CN100524445C - Driving method for liquid crystal display device assembly - Google Patents

Abstract

Disclosed is a driving method for a liquid crystal display device assembly, which includes: a transmissive liquid crystal display device, a planar light source device including P*Q planar light source units, and a driving circuit for driving the two devices. The driving method includes the step of, in the case where the value of the input signal input into the driving circuit is represented by x, in each display area unit, when the value x of the input signal for any pixel is greater than or equal to a predetermined value , where this value is denoted by x _U-max , the luminance of the planar light source unit corresponding to the display area unit is controlled, so that it can be obtained that a control signal corresponding to an input signal having a value greater than x _U-max is provided to Pixel luminance in the case of a pixel.

Description

Driving method for liquid crystal display device assembly

References to related applications

The present invention contains subject matter related to Japanese Patent Application No. JP2005-343320 filed with the Japan Patent Office on November 29, 2005 and Japanese Patent Application No. JP2006-244330 filed with the Japan Patent Office on September 8, 2006, the entire contents of which are adopted by References are included here.

technical field

The invention relates to a method for driving a liquid crystal display assembly including a liquid crystal device and a planar light source device.

Background technique

In a liquid crystal display device, the liquid crystal material itself does not emit light. Instead, a direct emission type planar light source device (backlight) is provided at the rear surface of the liquid crystal display device for emitting light. In a color liquid crystal display device, one pixel is constituted by three sub-pixels such as a sub-pixel emitting red (R) light, a sub-pixel emitting green (G) light, and a sub-pixel emitting blue (B) light. Then, by operating the liquid crystal cell constituting one pixel or sub-pixel as a type of optical shutter (light valve), that is, by controlling the light transmittance (aperture ratio) of each pixel or each sub-pixel, it is possible to control the The amount (ratio) of illuminating light (eg, white light) emitted by a device through that pixel or subpixel to display an image. As the size of liquid crystal display devices has increased in recent years, the size of planar light source devices has also increased.

The known planar light source device illuminates the entire display area of the liquid crystal display device with uniform and constant brightness. Another type of planar light source device is also known from, for example, Japanese Unexamined Patent Application Publications Nos. 2004-212503 and 2004-246117. The planar light source devices disclosed in these gazettes include a plurality of planar light source units corresponding to a plurality of display area units constituting the entire display area of a liquid crystal display device, and control the lighting conditions of the planar light source units to change the distribution of illumination in the display area units .

Basically, the above-mentioned planar light source device is controlled according to the following method. It should be noted that a signal is externally input to the drive circuit, and based on this input signal, a control signal for controlling the light transmittance of the pixel is generated for each pixel and supplied to the pixel from the drive circuit. Assuming now that the maximum luminance of each planar light source unit constituting the planar light source device is indicated by _Ymax , the maximum light transmittance (aperture ratio) (more specifically, for example, 100%) of the pixels constituting each display area unit is indicated by Lt _max indicates that the light transmittance (aperture ratio) of each pixel is used to obtain the luminance of the display area (hereinafter may be referred to as "display luminance y") when each planar light source unit exhibits the maximum luminance Y _max Indicated by Lt. In this specification, the display luminance y obtained from the light source luminance Y and the light transmittance Lt can be expressed by the following formula (A) using the operator **.

y=Y**Lt (A)

In this case, the light source luminance Y of each planar light source unit constituting the planar light source device should be controlled to satisfy the following formula.

Y**Lt _max ＝Y _max **Lt

The concept of the control method described above is shown in Figs. 28A and 28B. In this case, the light source luminance Y of the planar light source unit is changed for each frame (referred to as "image display frame") for displaying an image on the liquid crystal display device.

Contents of the invention

The contrast ratio in a color liquid crystal display device (the illuminance ratio of a completely white display portion to a completely black display portion on the screen surface of a color liquid crystal display device not including reflection of external light) is the ratio of the maximum light transmittance per pixel to the minimum Ratio of light transmittance. Currently, a color liquid crystal display device that can achieve a contrast ratio of about 1000:1 is considered to be a high-performance liquid crystal display device. In order to further improve the contrast ratio, it is necessary to increase the illuminance of the all-white display portion. One of the ways to achieve this is to increase the illumination of a planar light source arrangement, as shown schematically in FIG. 29 . However, in this method, the luminance of a completely black display portion is also increased, and a so-called "black graying" phenomenon occurs, which makes the display state on the screen unnatural compared with other types of display devices. In contrast, in a cathode ray tube (CRT), automatic brightness limiting (ABL) control may be performed to increase the luminance of only a white display portion, so that the luminance of white unique to the CRT can be obtained. More specifically, the luminance of the white display portion is 500 cd/m ² , and the luminance of the other portions is 300 cd/m ² . However, in the color liquid crystal display device, as far as the present inventors have investigated, there is no specific method for increasing the luminance of the white display portion to a level higher than that of other display portions. In addition, none of the above-mentioned publications, ie, Japanese Unexamined Patent Application Nos. 2004-212503 and 2004-246117, discloses or proposes a specific method for further enhancing the contrast ratio or increasing the luminance level of the white display portion.

It is therefore desired to provide a driving method for a liquid crystal display device assembly capable of increasing the luminance of a specific display portion to a level higher than that of other display portions. There is also a need to provide a driving method for a liquid crystal display device assembly that can further increase the contrast ratio and increase the luminance level.

According to one embodiment of the present invention, a first driving method for a liquid crystal display device assembly is provided, the liquid crystal display device assembly comprising: (A) a transmissive liquid crystal display device including a display area in which pixels are arranged in a two-dimensional matrix, ( B) A planar light source device comprising P×Q planar light source units corresponding to virtual P×Q display area units, assuming that the display area of the transmissive liquid crystal display device is divided into virtual P×Q display area units, the planar light source The device illuminates the display area unit corresponding to the planar light source unit from the rear surface of the display area unit, and (C) a drive circuit that drives the planar light source device and the transmissive liquid crystal display device, the drive circuit provides each pixel with a Control signal for the light transmittance of the pixel. Assume now that the value of the input signal for driving the pixel input to the drive circuit is denoted by x, and the maximum value of the input signal for driving the pixel input to the drive circuit is indicated by x _max .

Each coefficient to be described below is set to be in the following range.

k ₀ : 0.06≤k ₀ ≤0.3

k ₁ : 0.94≤k ₁ ≤0.99

k ₂ : 0.35≤k ₂ ≤0.5

α ₀ : 0.95≤α ₀ ≤1.0

α ₁ : 0.3≤α ₁ ≤0.8

α ₂ : 0.01≤α ₂ ≤0.2

In the above-mentioned first driving method for a liquid crystal display device assembly, in each display area unit, when the value x of the input signal for any pixel constituting the display area unit is greater than or equal to a predetermined value, wherein the value x of the input signal When the value is indicated by x _U-max , the luminance of the planar light source unit corresponding to the display area unit is controlled by the drive circuit, so that it can be obtained that the control signal corresponding to the input signal with a value greater than x _U-max is provided to the pixel The pixel luminance in the case of . In this case, the light transmittance of each pixel constituting the display area unit can also be controlled if necessary.

In the first driving method described above, in the case where the predetermined value is indicated by k ₁ ·x _max , in each display area unit, when the value x of the input signal for any pixel constituting the display area unit is greater than or equal to k ₁ x _max , that is, x≥k ₁ x _max (1), where the value of the input signal is indicated by x _U-max , the drive circuit can control the luminance of the planar light source unit corresponding to the display area unit , so that the pixel luminance under the assumption that the value of the control signal corresponding to the input signal is equal to x _U-max +k ₀ ·x _max (2) can be obtained. In this case, the light transmittance of each pixel constituting the display area unit is also controlled as necessary.

In the above-mentioned first driving method, each pixel may include a group of three sub-pixels, which are sub-pixels emitting R light, sub-pixels emitting G light, and sub-pixels emitting B light. Assume now that the values of the input signals input into the driving circuit for driving the R light-emitting sub-pixels, the G light-emitting sub-pixels and the B light-emitting diodes are denoted by _xR , _xG and _xB , respectively. In the case where the predetermined value is represented by k ₁ ·x _max , in each display area unit, when all values x _R , x _G , and x _B used for any pixel constituting the display area unit are greater than or equal to k ₁ x _max , that is, x _R ≥k ₁ x _max (1-1), x _G ≥k ₁ x _max (1-2) and x _B ≥k ₁ x _max (1-3), where the input When the values of the signals are respectively represented by x _U-max (R), x _U-max (G) and x _U-max (B), the drive circuit can control the luminance of the plane light source unit corresponding to the display area unit, thereby A control corresponding to an input signal assumed to have a value equal to (x _U-max(R) +x _U-max(G) +x _U-max(B) )/3+k ₀ ·x _max (2') can be obtained The signal is supplied to the R-emitting sub-pixel, the G-emitting sub-pixel, and the B-emitting sub-pixel luminance in the case of the R-emitting sub-pixel, the G-emitting sub-pixel, and the B-emitting sub-pixel. In this case, the light transmittance of each pixel constituting the display area unit is also controlled as necessary.

According to another embodiment of the present invention, a second driving method for a liquid crystal display device assembly is provided. The driving method includes the following steps: when the value x of the input signal for any pixel constituting the display area unit is greater than or equal to a predetermined value, wherein the value of the input signal is represented by x _U-max , the drive circuit controls and displays The luminance of the planar light source unit corresponding to the area unit, so that the pixel luminance under the assumption that a control signal corresponding to an input signal having a value greater than x _U-max is supplied to the pixel can be obtained; and in each display area unit , if the value x of the input signals for all the pixels constituting the display area unit is smaller than the predetermined value, the maximum value of the input signals for driving all the pixels constituting the display area unit input to the driving circuit is represented by x' In the case of _U-max , the luminance of the planar light source unit corresponding to the display area unit is controlled by the drive circuit, so that the control signal corresponding to the input signal whose value is equal to the maximum value x' _U-max can be obtained. The pixel luminance if supplied to the pixel. In this case, the light transmittance of each pixel constituting the display area unit is also controlled as necessary. With this configuration, although the image quality may change because the gamma (γ) characteristic slightly deviates from the ideal characteristic, this change will be negligible.

In the above-mentioned second driving method, in each display area unit, when the value x of the input signal for any pixel constituting the display area unit is greater than or equal to k ₁ ·x _max , that is, x≥k ₁ · x _max (1), when the value of the input signal is represented by x _U-max , the luminance of the plane light source corresponding to the display area unit can be controlled by the drive circuit, so that it can be obtained under the assumption that the value is equal to x _U-max +k The pixel luminance when the control signal corresponding to the input signal of ₀ x _max (2) is supplied to the pixel. In each display area unit, when the value x of the input signal used for any pixel constituting the display area unit is less than k ₁ ·x _max , and when the value x input to the drive circuit for driving the display area unit When the maximum value of the input signals of all pixels is represented by x' _U-max , the luminance of the planar light source unit corresponding to this display area unit can be controlled by the drive circuit, so that it can be obtained under the assumption that the value is equal to the maximum value x' _{U -max} is the pixel luminance in the case where the input signal corresponding to the control signal is supplied to the pixel. In this case, the light transmittance of each pixel constituting the display area unit is also controlled as necessary.

In the second driving method described above, each pixel may include a group of three sub-pixels, which are an R-emitting sub-pixel, a G-emitting sub-pixel, and a B-emitting sub-pixel. Assume now that the input signals input into the driving circuit for driving the R light-emitting sub-pixels, the G light-emitting sub-pixels and the B light-emitting diodes are denoted by _xR , _xG and _xB , respectively. In the case where the predetermined value is represented by k ₁ ·x _max , in each display area unit, when all the values x _R , x _G , and x _B for any pixel constituting the display area unit are greater than or equal to k ₁ x _max , that is, x _R ≥k ₁ x _max (1-1), x _G ≥k ₁ x _max (1-2) and x _B ≥k ₁ x _max (1-3), where the input When the signal values are respectively represented by _xU-max(R) , _xU-max(G) and _xU-max(B) , the luminance of the plane light source unit corresponding to the display area unit can be controlled by the driving circuit, so that A control corresponding to an input signal assumed to have a value equal to (x _U-max(R) +x _U-max(G) +x _U-max(B) )/3+k ₀ ·x _max (2') can be obtained The signal is supplied to the luminance of the R-light emitting sub-pixel, the G-light-emitting sub-pixel, and the B-light-emitting sub-pixel in the case of the R-light-emitting sub-pixel, the G-light-emitting sub-pixel, and the B-light-emitting sub-pixel. In each display area unit, when any value x _R , x _G , and x _B of all the pixels constituting the display area unit is smaller than k ₁ ·x _max , and when the input to the driving circuit is used to drive the When the maximum value of the input signals for the R light-emitting sub-pixel, the G light-emitting sub-pixel and the B light-emitting sub-pixel of all pixels in the display area unit is represented by x' _U-max , the plane corresponding to the display area unit can be controlled by the driving circuit The luminance of the light source unit, so that it can be obtained under the assumption that a control signal corresponding to an input signal having a value equal to the maximum value x' _U-max is supplied to the R-emitting sub-pixel, the G-emitting sub-pixel and the B-emitting sub-pixel The pixel luminance of the R light-emitting sub-pixel, the G light-emitting sub-pixel, and the B light-emitting sub-pixel. In this case, the light transmittance of each pixel constituting the display area unit is also controlled as necessary.

In the first and second driving methods described above, the planar light source unit may include light emitting diodes, and in this case, it is possible to increase or decrease the pulse width modulation (PWM) used in the control of the light emitting diodes constituting the planar light source unit. Increase or decrease the luminance of the planar light source unit according to the duty ratio. A duty ratio D 0 of pixel luminance can be obtained assuming that a control signal corresponding to an input signal having a value equal to (1+k ₀ )x _max is supplied to the pixel can _{be obtained by D 0 =} α ₀ ·D _max (4) Indicates that D _max represents the maximum load ratio. For convenience, increasing or decreasing the luminance of the planar light source by increasing or decreasing the duty ratio used in the PWM control of the light emitting diodes constituting the planar light source unit is referred to as "duty ratio based increase/decrease control for Illumination control method for planar light source unit". In the second driving method for an assembly of a liquid crystal display device, when the above-described illumination control method is employed, it is possible to obtain a pixel under the assumption that a control signal corresponding to an input signal having a value equal to k ₁ ·x _max is supplied to the pixel The duty ratio D ₁ of luminance can be expressed by D ₁ =α ₁ ·D _max (5), where D _max represents the maximum duty ratio.

In the second driving method for the liquid crystal display device assembly, in the case where the maximum value x' _U-max is expressed by x' _U-max ≤ k ₂ ·x _max (3), the display area can be controlled by the control circuit The luminance of the planar light source unit corresponding to the unit, so that the input signal can be obtained under the assumption that the value is equal to x' _U-max /k ₂ (or x' _U-max /{(k ₂ ·x _max )/x _max }) The pixel luminance where the corresponding control signal is supplied to the pixel. With this configuration, ideal gamma characteristics can be maintained, and the contrast ratio can be increased without changing image quality. The relationship between k ₁ and k ₂ can be represented by, for example, 0.35≦k ₂ /k ₁ ≦0.53. In this case, the planar light source unit may include light emitting diodes, and the brightness of the planar light source may be increased or decreased by increasing or decreasing a duty ratio used in pulse width modulation control of the light emitting diodes constituting the planar light source unit. Spend. The duty ratio D ₀ of pixel luminance under the assumption that a control signal corresponding to an input signal having a value equal to (1+k ₀ )x _max is supplied to the pixel can be obtained by D ₀ =α ₀ ·D _max (4) Indicates that D _max represents the maximum load ratio. When the illumination control method for a planar light source unit based on duty ratio increase/decrease control is employed, it is possible to obtain the brightness of a pixel under the assumption that a control signal corresponding to an input signal having a value equal to k ₁ ·x _max is supplied to the pixel. The degree of duty ratio D ₁ can be expressed by D ₁ =α ₁ ·D _max (5), where D _max represents the maximum duty ratio. The duty ratio D 2 that can obtain the pixel luminance under the assumption that a control signal corresponding to an input signal having a value equal to k ₂ ·x _max is supplied to the pixel can be expressed by _{D 2 =} α ₂ ·D _max (6), where D _max represents the maximum duty ratio. If the contrast ratio of the liquid crystal display device is 10 ³ :1, the contrast ratio increases to 5×10 ³ :1 when α ₂ =0.2, and increases to 10 ⁵ :1 when α ₂ =0.01.

In the first and second driving methods described above, x' _U-max ranges from 0 to x _max . Values obtained by multiplying the value x of the input signal and the value X of the control signal by the respective coefficients should be rounded. Accordingly, rounding errors occurring in the respective calculations should be dealt with, for example, by ideal calculation algorithms.

The number of pixels satisfying formula (1) (or formulas (1-1), (1-2) and (1-3)) in the planar light source unit is not particularly limited. For example, the number of pixels may be one, or may be in the range from 1% to 25% of the number of pixels constituting one display area unit. If the number of pixels is in the range from 1% to 25%, the mean value of the input signals of a plurality of pixels satisfying equation (1) can be used as the first term in equation (2), or satisfying equation (1-1 ), (1-2) and (1-3) the average value of the input signal of multiple pixels [(x _U-max(R) +x _U-max(G) +x _U-max(B) )/3 ] can be used as the first term in equation (2'). Alternatively, the maximum value of input signals of a plurality of pixels satisfying equation (1) may be used as the first term in equation (2), or satisfying equations (1-1), (1-2) and (1-3 ) The mean value of the input signal of multiple pixels [(x _U-max(R) +x _U-max(G) +x _U-max(B) )/3] can be used as the First item.

It is used to obtain the input signal that can take on various values of x (or the sub-pixels that emit R light, the sub-pixels that emit G light, and the sub-pixels that emit B light can take values x _R , x _G and x _B (x _R =x _G =x _B ) The luminance and duty ratio of the planar light source unit of the pixel luminance when the input signal) is supplied to the pixel are predetermined through various tests. Various data based on the determined luminance are preferably stored in the drive circuit. And various coefficients and parameters such as x _max , k ₀ , k ₁ , k ₂ , α ₀ , α ₁ , α ₂ , D _max , D ₀ , D ₁ and D ₂ are also preferably stored in the driving circuit.

In each of the planar light source units constituting the planar light source device, light sources other than light-emitting diodes, such as cold cathode ray fluorescent lamps, electroluminescence (EL) devices, cold cathode field electron emission devices (FED), plasma displays, etc., can be used. devices, or conventional lamps, etc. If a light-emitting diode is used as a light source, an R-color light-emitting diode whose emission wavelength is, for example, 640 nm, a G-color light-emitting diode whose emission wavelength is, for example, 530 nm, and a light-emitting diode whose emission wavelength is, for example, B light of 450 nm can be used. A group of LEDs consisting of B LEDs can be used to obtain white light, or LEDs emitting white light (eg, a combination of UV or blue LEDs and fluorescent particles) can be used. In addition, light emitting diodes emitting fourth colors, fifth colors, etc. other than R, G, and B colors may also be provided.

The planar light source units constituting the planar light source device may be separated using a fence. In this case, a planar light source unit is surrounded by four bars, or three bars and one side of the housing (discussed below), or two bars and two sides of the housing. Assume now that the planar light source unit consists of a light-emitting diode unit that emits white light by mixing all colors (it is a combination of one R-emitting diode, one G-emitting diode, and one B-emitting diode, one R-emitting diode, two G-emitting diodes A combination of a light emitting diode and a B light emitting diode, or a combination of two R light emitting diodes, two G light emitting diodes and a B light emitting diode). In this case, a planar light source unit is provided with at least one light emitting diode or at least one white light emitting diode.

A lens such as a Lambertian lens exhibiting high light intensity in a vertical direction, or a two-dimensional emission structure emitting light mainly in a horizontal direction may be attached to the light emitting part of the light emitting diode.

The light emitting diode may have a so-called "face-up structure" or a "flip-chip structure". That is, the light-emitting diode is composed of a substrate and a light-emitting layer formed on the substrate, and light emitted from the light-emitting layer may be output to the outside of the diode, or light emitted from the light-emitting layer may pass through the substrate and be output to the outside of the diode. . More specifically, the light emitting diode has a stacked structure including a first composite layer formed of a first conductivity type (for example, n-type) compound semiconductor layer formed on a substrate, an active layer formed on the first composite layer, and a second composite layer composed of a composite semiconductor layer of a second conductivity type (eg, p-type) formed on the active layer. The LED is provided with a first electrode electrically connected to the first composite layer and a second electrode electrically connected to the second composite layer. The individual layers forming the light-emitting diode can be composed of known compound semiconductor materials taking into account the emission wavelength.

The planar light source device may include a diffusion plate, a reflection sheet, and an optical function sheet group including a diffusion sheet, a prism sheet and a polarization conversion sheet.

The transmissive liquid crystal display device includes a front panel with a first transparent electrode, a rear panel with a second transparent electrode, and a liquid crystal material disposed between the front panel and the rear panel.

More specifically, the front panel includes a first substrate made of, for example, a glass substrate or a silicon substrate, a so-called "common electrode" made of, for example, indium tin compound (ITO) provided on the lower surface of the first substrate. The first transparent electrode and the polarizing film arranged on the upper surface of the first substrate. In the transmissive type color liquid crystal display device, a color filter covered with a protective film layer made of acrylic resin or epoxy resin is provided on the lower surface of the first substrate. The layout pattern of color filters can be triangular, strip, diagonal or rectangular pattern. A first transparent electrode is formed on the protective film layer. An alignment film is also formed on the first transparent electrode. The rear panel includes a second substrate made of, for example, a glass substrate or a silicon substrate, a switching element formed on the upper surface of the second substrate, a second transparent electrode (also referred to as a "pixel electrode") electrically connected to the switching element. electrode" made of, for example, ITO), and a polarizing film provided on the lower surface of the second substrate. An alignment film is formed on the entire surface of the switching element and the second transparent electrode. Known components and materials can be used for liquid crystal display devices including transmissive color liquid crystal display devices. As the switching element, a three-terminal element such as a MOS field effect transistor (FET) or a thin film transistor (TFT) formed on a single crystal silicon semiconductor substrate, or a metal-insulator-metal (MIM) element, a varistor element, etc. , or two-terminal devices such as diodes.

A region of the liquid crystal cell including the overlap of the first transparent electrode and the second transparent electrode corresponds to one pixel or one sub-pixel. In a transmissive color liquid crystal display device, the above region and the R color filter emitting R light constitute the R light emitting sub-pixel (R sub-pixel) of each pixel; the above region and the G color filter emitting G light constitute the G photon emission of each pixel Pixel (G sub-pixel); the above region and the B color filter that emits B light constitute a B-light-emitting sub-pixel (B sub-pixel) of each pixel. The arrangement mode of the R sub-pixels, the G sub-pixels and the B sub-pixels is consistent with the arrangement mode of the above-mentioned color filters. In addition to R, G, and B sub-pixels, pixels can also be composed of sub-pixels that emit white light to increase luminance, sub-pixels that emit complementary color light to increase the color reproduction range, yellow light that Yellow and cyan lights are composed of sub-pixels that expand the range of color reproduction. In this case, sub-pixels other than the R, G, and B sub-pixels can also be subjected to similar control to that performed on the R, G, and B sub-pixels.

In the case where the number of pixels set in a two-dimensional matrix is represented by M ₀ ×N ₀ (M ₀ , N ₀ ), the specific value of (M ₀ , N ₀ ) can be distinguished by displaying several images as shown in Table 1 Degree representation, such as VGA (640, 480), S-VGA (800, 600), XGA (1024, 768), APRC (1152, 900), S-XGA (1280, 1024), U-XGA (1600, 1200 ), HD-TV (1920, 1080), Q-XGA (2048, 1536), (1920, 1035), (720, 480), (1280, 960), etc. may be indicated. However, the number of pixels is not limited to those resolutions. The relationship between (M ₀ , N ₀ ) and (P, Q) (P×Q is the number of display area units) is not limited, but may be as shown in Table 1. The number of pixels constituting one display area unit may range from 20×20 to 320×240, and more preferably range from 50×50 to 200×200. Depending on the display area unit, the number of pixels constituting one display area unit may be the same or different.

Table 1

P Q VGA (640, 480) 2～32 2～24 S-VGA (800, 600) 3～40 2～30 XGA (1024, 768) 4～50 3～39 APRC (1152, 900) 4～58 3～45 S-XGA (1280, 1024) 4～64 4～51 U-XGA (1600, 1200) 6～80 4～60 HD-TV (1920, 1080) 6～86 4～54 Q-XGA (2048, 1536) 7～102 5～77 (1920, 1035) 7～64 4～52 (720, 480) 3～34 2～24 (1280, 960) 4～64 3～48

A driving circuit for driving a liquid crystal display device and a planar light source device includes a planar light source device control circuit having an LED drive circuit, a calculation circuit, a storage unit (memory), etc., and a liquid crystal display device having a known circuit such as a timing controller Drive circuit. The luminance of a display area (display luminance) corresponding to a pixel or a sub-pixel or the luminance of a planar light source unit (light source luminance) is controlled for each image display frame. The number of image information items sent to the drive circuit as electrical signals per second is the frame frequency (frame rate), and the inverse of the frame frequency is the frame time (second).

Light transmittance (also referred to as "aperture ratio") Lt of a pixel or sub-pixel, luminance (display luminance) y of a display area corresponding to a pixel or sub-pixel, and luminance (light source luminance) Y of a planar light source unit It is defined as follows. The maximum value x _max of the input signal input to the driving circuit for driving the pixels is a maximum value designed for the input signal. The value of the control signal corresponding to an input signal of value x is denoted by X, and the coefficients for the control signal corresponding to the coefficients k ₀ , k ₁ , k ₂ for the input signal are denoted by K ₀ , K ₁ , K , respectively. ₂ said.

Y _max : Maximum light source luminance (contrast) in the planar light source unit

Y _std : Light source luminance (constant) of a known planar light source device that illuminates the entire display area of a liquid crystal device with uniform and constant luminance, Y _std <Y _max

Lt _max : light transmittance (aperture ratio) of a pixel (sub-pixel) of a display area unit under the assumption that a control signal corresponding to an input signal having a maximum value Y _max is supplied to a pixel (or sub-pixel)

y _max : Assuming that a control signal corresponding to an input signal having a value (for example, x _U-max +k ₀ ·x _max ) greater than the value x _U-max of the input signal is supplied to the pixel, when the light source luminance is The display brightness of the pixel at Y _max

y' _max : Assuming that a control signal corresponding to an input signal of value x' _U-max is supplied to the pixel, the display luminance of the pixel when the light source luminance is Y _std

y" _max : Under the assumption that a control signal corresponding to an input signal having a value of k ₂ x _max is supplied to the pixel, the display luminance of the pixel when the light source luminance is Y _std

Lt[X/X _MAX ]: Normalized light transmittance (aperture Ratio), where X _MAX takes X _max or (1+K ₀ )X _max according to X

Y _Mdfy : the luminance of the planar light source unit controlled by the drive circuit

Y”: the luminance of the light source when the display luminance y” _max is obtained by Lt[K ₂ ·X _max /X _max ]

Now assume that the amount of light input to the pickup tube is denoted by _yin , and as an output signal from the pickup tube, for example, an input signal output from a broadcasting station and input into a driving circuit to control the light transmittance of a pixel is denoted by x, and assuming When the control signal X corresponding to the input signal is supplied to the pixel, the display luminance of the pixel is represented by y. In this case, the input signal value x can be expressed by the 0.45 power of the input light amount y _in , that is, a function of y _in ^0.45 , and the control signal value X or display luminance y can be expressed by the 2.2 power of the input signal x, that is, x ^2.2 function representation. The relationship between the function showing the luminance y and the input signal x is called the gamma (γ) characteristic, and the γ characteristic can be expressed as:

y=x ^2.2 ＝(y _in ^0.45 ) ^2.2 ＝y _in

In this way, a system from a broadcasting station to a television receiver or from a video playback device to a television receiver is constructed so that the image captured by the camera tube can be accurately reconstructed. Depending on the control of the light source luminance of the planar light source unit, correction of the light transmittance of the pixels constituting the associated display area unit may be necessary.

In the following description, for convenience, a display area unit having pixels satisfying expression (1) or simultaneously satisfying expressions (1-1), (1-2) and (1-3) is referred to as "realizing improved luminance display lighting unit", and a planar light source unit corresponding to such a display area unit is referred to as a "planar light source unit realizing improved luminance". In contrast, a display area unit that does not have any pixels satisfying Equation (1) or has pixels satisfying only parts of Equations (1-1), (1-2), and (1-3) is referred to as "unrealized improved A display area unit with luminance", and a planar light source unit corresponding to such a display area unit is called a "planar light source unit that does not realize enhanced luminance".

If y _max , y′ _max and y” _max are expressed based on the above-mentioned formula (A), the following formulas are true.

y _max ＝Y _max **Lt[(X _U-max +K ₀ ·X _max )/{(1+K ₀ )X _max }

y' _max ＝Y _std **Lt[X' _U-max /X _max ]

y” _max = Y _std **Lt[K ₂ ·X _max )/X _max )]

According to the first or second driving method for the liquid crystal display device assembly, in each display area unit, when the value x of the input signal for any pixel constituting the display area unit is greater than or equal to a predetermined value (for example, k ₁ ·x _max ), wherein when the value of the input signal is represented by x _U-max , the luminance of the planar light source unit corresponding to the display area unit to achieve improved luminance can be controlled by the drive circuit, so that it can be obtained between assumptions and values ( For example, x _U-max +k ₀ ·x _max ) is greater than the pixel luminance in case the control signal corresponding to the input signal having a value x _U-max is supplied to the pixel. In this case, any one of the following three control modes can be used.

Control Mode 1A

In the control mode 1A, regardless of the input signal value x _U-max , the light source luminance of the planar light source unit realizing increased luminance is set to, for example, Y _max . Then, the light transmittance (aperture ratio) Lt _Mdfy of the pixel exhibiting the maximum luminance (pixel (A)) to which the control signal corresponding to the input signal value x _U-max is supplied is set to obtain the display luminance y _max value. More specifically, although the original light transmittance (aperture ratio) of the pixel is Lt[X/X _MAX ] when the input signal value is x, in control mode 1A, a frame is displayed for each image under the control of the driving circuit Correct this transmittance to Lt _Mdfy . More specifically, when the input signal value is x _U-max , the light transmittance of the pixel is set as:

Lt[(x _U-max +K ₀ ·X _max )/(1+K ₀₎ X _max ] (11)

Control Mode 1B

In the control mode 1B, the luminance of the planar light source unit achieving increased luminance is increased according to the increase of the input signal value x _U-max . More specifically, under the control of the drive circuit, for each image display frame, the light source luminance Y _Mdfy is set to a value that can obtain the display luminance y _max when the light transmittance is Lt[X _U-max /X _max ] (see formula (12)).

Y _Mdfy **Lt[X _U-max /X _max ]

=Y _max **Lt[(X _U-max +K ₀ ·X _max )/(1+K ₀ )X _max ] (12)

In the control mode 1B, although the light source luminance Y _Mdfy of the planar light source unit realizing increased luminance is controlled, the light transmittance (aperture ratio) of the pixels constituting the display area unit is not changed or corrected. That is, when the input signal value is x, the light transmittance of the pixel is Lt[X/X _max ]

Control Mode 1C

In control mode 1C, the light transmittance (aperture ratio) of the pixel exhibiting the maximum luminance (pixel A) constituting the display area unit realizing enhanced luminance is set constant regardless of the input signal value x _U-max Lt _max , and the planar light source unit realizing increased luminance is controlled so that desired display luminance can be obtained. More specifically, in this case, under the control of the drive circuit, for each image display frame, the light source luminance Y _Mdfy is set to a value that can obtain the display luminance y _max when the light transmittance is Lt _max (see Eq. (13)).

Y _Mdfy **Lt _max

=Y _max **Lt[(X _U-max +K ₀ ·X _max )/(1+K ₀ )X _max ] (13)

In the control mode 1C, the light source luminance Y _Mdfy of the planar light source unit realizing increased luminance is controlled, and the light transmittance (aperture ratio) of pixels constituting the display area unit realizing increased luminance is also corrected.

In the first driving method for a liquid crystal display device, in each display area unit, if the input signal value x for all pixels constituting the display area unit does not satisfy the formula x≥k ₁ ·x _max (1) , then the luminances of all planar light source units corresponding to such display area units that do not achieve enhanced luminance are set to be constant. That is, if there are a plurality of display area units that do not achieve enhanced luminance, the luminances of the planar light source units corresponding to these display area units are set to be the same. When controlling the luminance of a planar light source unit corresponding to a display area unit that does not realize enhanced luminance, the following control mode may be employed.

Control Mode 2A

In the control mode 2A, as in the related art, the light source luminance of the planar light source unit that does not achieve enhanced luminance is set to, for example, Y _std for each image display frame. In the control mode 2A, the light transmittance itself of the pixels constituting the display area unit is not changed or corrected in response to the control of the light source luminance Y _std of the planar light source unit that does not achieve enhanced luminance. The light source luminance Y _std is constant regardless of the value of the input signal.

In the second driving method for a liquid crystal display device, in each display area unit, if the input signal value x for all pixels constituting the display area unit does not satisfy the formula x≥k ₁ ·x _max (1), Then the luminance of the planar light source unit corresponding to the display area unit is controlled by the drive circuit, so as to obtain the maximum value of the input signal input to the drive circuit for driving all the pixels constituting the display area unit, that is, x _{U -max} is the pixel luminance in the case where the input signal corresponding to the control signal is supplied to the pixel. In this case, the following control modes are available.

Control Mode 2B

In the control mode 2B, the light transmittance (aperture ratio) of the pixel exhibiting the maximum luminance (pixel B) constituting the display area unit not realizing the enhanced luminance is set regardless of the input signal value x′ _U-max is the constant value Lt _max . The planar light source units that do not achieve enhanced luminance are controlled so that desired display luminance can be obtained in the associated display area unit. More specifically, under the control of the drive circuit, the light source luminance Y _Mdfy is set to a value such that the display luminance y' _max can be obtained when the light transmittance is Lt _max for each image display frame (see formula (14)) .

Y _Mdfy **Lt _max

=Y _Std **Lt[(X' _U-max /X _max ] (14)

In the control mode 2B, the light source luminance Y _Mdfy of the planar light source unit not realizing enhanced luminance is controlled, and the light transmittance (aperture ratio) of the pixels constituting the associated display area unit is also corrected.

In the second driving method for the liquid crystal display device, if x′ _U-max ≦k ₂ ·x _max (3) is true, the following control modes can be employed.

Control Mode 2C

In the control mode 2C, regardless of the input signal value x' _U-max of the input signal satisfying the formula (3), the light source of the planar light source unit corresponding to the display area unit satisfying the formula (3) does not realize improved luminance The luminances are all set to a constant value Y". In this case, the light transmittance Lt _Mdfy of the pixel exhibiting the maximum luminance (pixel B) constituting the display area unit is set to a value at which the display luminance y" _max can be obtained. value. More specifically, when the input signal value is x, the original light transmittance (aperture ratio) of the pixel is Lt[X/X _max ]. However, in the control mode 2C, the light transmittance of the pixel is corrected to Lt _Mdfy for each image display frame under the control of the drive circuit. More specifically, when the input signal value is x' _U-max , the light transmittance of the pixel is set as:

Lt[X' _U-max /{(K ₂ ·X _max )/X _max }] (15)

Combinations of control modes usable in the first and second driving methods are as follows.

first drive method

Control Mode 1A and Control Mode 2A

Control Mode 1B and Control Mode 2A

Control Mode 1C and Control Mode 2A

Second drive method

Control Mode 1A and Control Mode 2B

Control Mode 1A, Control Mode 2B and Control Mode 2C

Control Mode 1B and Control Mode 2B

Control Mode 1B, Control Mode 2B and Control Mode 2C

Control Mode 1C and Control Mode 2B

Control Mode 1C, Control Mode 2B and Control Mode 2C

In the first driving method according to an embodiment of the present invention, in order to control the light transmittance of each pixel constituting each display area unit, when the input signal value x input to the driving circuit is greater than or equal to When the upper limit threshold value k ₁ ·x _max obtained by multiplying the maximum value x _max by k ₁ (k ₁ <1), the luminance of the planar light source unit corresponding to the display area unit that realizes the increased luminance is controlled (increased) by the drive circuit. luminance of a pixel when it is assumed that a control signal corresponding to an input signal whose value is obtained by adding the offset k ₀ ·x _max to the input signal value x _U-max is supplied to the pixel. Thereby, the luminance of a display area unit including a display section (also referred to as a "white display section") including a control signal supplied with an input signal greater than or equal to an upper threshold value can be raised higher than that of other display areas. The level of the luminance of the units (the pixel values X constituting these display area units all exceed the upper threshold). Thereby, a white brightness similar to that obtained with a CRT can be achieved.

In the second driving method according to another embodiment of the present invention, white brightness similar to that obtained by a CRT can also be achieved. Furthermore, in each planar light source unit, if the input signal value x for all pixels does not exceed the upper limit threshold, the luminance of the planar light source unit corresponding to the display area unit that does not realize the enhanced luminance is raised or lowered by the driving circuit. degree, so that it is possible to obtain a control signal corresponding to an input signal whose value is equal to the maximum value x' _U-max of the input signals input to the driving circuit for controlling all the pixels constituting the display area unit that does not realize the enhanced luminance, assuming that it can be obtained The pixel luminance if supplied to the pixel. Thereby, the contrast ratio can be further improved.

Description of drawings

Fig. 1 schematically shows the relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the pixel and the display luminance y in the first embodiment;

Fig. 2 shows the relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the pixel and the display luminance y in the second embodiment;

Fig. 3 shows the relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the pixel and the display luminance y in the third embodiment;

Fig. 4 shows the relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the pixel and the display luminance y in the fourth embodiment;

Fig. 5 shows the relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the pixel and the display luminance y in the fifth embodiment;

Fig. 6 shows the relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the pixel and the display luminance y in the sixth embodiment;

Fig. 7 shows the relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the pixel and the display luminance y in the seventh embodiment;

Fig. 8 shows the relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the pixel and the display luminance y in the eighth embodiment;

Fig. 9 shows the relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the pixel and the display luminance y in the ninth embodiment;

10 shows the concept of the relationship among the light source luminance of the planar light source device, the light transmittance (aperture ratio) of the pixel, and the display luminance of the display area in the control mode 1A;

11A and 11B show the concept of the relationship among the light source luminance of the planar light source device, the light transmittance (aperture ratio) of the pixel and the display luminance of the display area in the control mode 1B;

12A and 12B show the concept of the relationship among the light source luminance of the planar light source device, the light transmittance (aperture ratio) of the pixel and the display luminance of the display area in the control mode 1C;

13A and 13B show the concept of the relationship among the light source luminance of the planar light source device, the light transmittance (aperture ratio) of the pixel and the display luminance of the display area in the control mode 2B;

14 shows the concept of the relationship among the light source luminance of the planar light source device, the light transmittance (aperture ratio) of the pixel and the display luminance of the display area in the control mode 2C;

15 is a flowchart illustrating a driving method for a liquid crystal display device assembly according to the first embodiment;

16 is a flowchart illustrating a driving method for a liquid crystal display device assembly according to a second embodiment;

17 is a flowchart illustrating a driving method for a liquid crystal display device assembly according to a third embodiment;

18 is a flowchart illustrating a driving method for a liquid crystal display device assembly according to a fourth embodiment;

19 is a flowchart illustrating a driving method for a liquid crystal display device assembly according to a fifth embodiment;

20 is a flowchart illustrating a driving method for a liquid crystal display device assembly according to the sixth embodiment;

21 is a flowchart illustrating a driving method for a liquid crystal display device assembly according to a seventh embodiment;

22 is a flowchart illustrating a driving method for a liquid crystal display device assembly according to the eighth embodiment;

23 is a flowchart showing a driving method for a liquid crystal display device assembly according to the ninth embodiment;

Fig. 24 shows the concept of a color liquid crystal display device assembly including a color liquid crystal display device and a planar light source device suitable for use in various embodiments;

Figure 25 shows a partial concept of a driver circuit suitable for use in various embodiments;

Figure 26A shows the arrangement of light emitting diodes in a planar light source device;

26B is a partial cross-sectional view showing a color liquid crystal display device assembly including a color liquid crystal display device and a planar light source device;

27 is a partial sectional view showing a color liquid crystal display device;

28A and 28B show the concept of the relationship between the light source luminance of the planar light source device in the known color liquid crystal display device assembly, the light transmittance (aperture ratio) of the pixel and the display luminance of the display area; and

FIG. 29 is a graph showing the relationship between control signal levels and display luminance, ie, pixel luminance, in a known color liquid crystal display device module.

Detailed ways

Before describing the present invention by description of preferred embodiments with reference to the accompanying drawings, an overview of a transmissive type color liquid crystal display device, a planar light source device, and a driving circuit suitable for use in each embodiment will be discussed with reference to FIGS. 24 to 27.

FIG. 24 shows the concept of the color liquid crystal display device 10 used in each embodiment. The color liquid crystal display device 10 includes a display area 11 with M ₀ pixels extending in the first direction and N ₀ pixels extending in the second direction, that is, a total of M ₀ ×N ₀ pixels are two-dimensionally set as a matrix. More specifically, these pixels exhibit an image display resolution satisfying the high-definition television (HD-TV) standard, and the numbers M ₀ and N ₀ of pixels are, for example, 1920 and 1080, respectively. A display area 11 including M ₀ ×N ₀ pixels indicated by a one-dot chain line is divided into P×Q virtual display area units 12 whose boundaries are indicated by dotted lines. The numbers P and Q are eg 19 and 12. However, for the sake of simplicity in FIG. 24 , the number of display area units 12 shown in FIG. 24 (that is, the number of planar light source units 42 described below) is different from 19×12. Each display area unit 12 is composed of a plurality of pixels (M×N), for example, 10,000 pixels. Each pixel is made up of multiple sub-pixels that emit different colors. More specifically, each pixel is composed of three sub-pixels, namely, a red-emitting sub-pixel (R sub-pixel), a green-emitting sub-pixel (G sub-pixel), and a blue-emitting sub-pixel (B sub-pixel). The transmissive color liquid crystal display device 10 is driven line-sequentially. More specifically, the color liquid crystal display device 10 includes scan electrodes (extending in a first direction) and data electrodes (extending in a second direction) intersecting each other in a matrix. The color liquid crystal display device 10 inputs scan signals into scan electrodes to select scan electrodes and scan pixels, and then displays images based on data signals (corresponding to control signals) input into data electrodes, thereby forming one frame.

As shown in the partial cross-sectional view in FIG. 27 , the color liquid crystal display device 10 includes a front panel 20 provided with a first transparent electrode 24, a rear panel 30 provided with a second transparent electrode 34, and 30 between 13 and 13 liquid crystal materials.

The front panel 20 includes a first substrate 21 composed of, for example, a glass substrate, and a polarizing film 26 provided on the upper surface of the first substrate 21 . A color filter 22 covered with a pellicle layer 23 made of, for example, acrylic resin or epoxy resin is provided on the lower surface of the first substrate 21 . A first transparent electrode (common electrode) 24 made of, for example, indium tin oxide (ITO) is formed under the protective film layer 23 , and an alignment film 25 is formed under the first transparent electrode 24 . The rear panel 30 includes a second substrate 31 made of, for example, a glass substrate, a switching element (more specifically, a thin film transistor (TFT)) 32 formed on the upper surface of the second substrate 31, the electrical connection of which is provided by the switching element 32 controls a second transparent electrode (also referred to as “pixel electrode”, made of, for example, ITO) 34 , and a polarizing film 36 disposed on the lower surface of the second electrode 31 . The alignment film 35 is formed on the entire surface of the switching element 32 and the second transparent electrode 34 . The front panel 20 and the rear panel 30 are bonded to each other at their outer edges with a sealing material (not shown) in between. The switching element 32 is not limited to a TFT, but may be a metal-insulator-metal (MIM) element. An insulating layer 37 is also formed between the switching elements 32 to insulate them from each other.

Known components and materials can be used to construct this transmissive color liquid crystal display device 10, and thus a detailed description thereof will be omitted here.

The direct light-emitting type planar light source device (backlight) 40 includes P×Q planar light source units 42 corresponding to P×Q virtual display area units 12, and each planar light source unit 42 is related to the planar light source unit 42 for illuminating from the rear surface. Linked display area unit 12. The light sources provided for the planar light source unit 42 are individually controlled. In FIG. 24 , the color liquid crystal display device 10 and the planar light source device 40 are shown separately, that is, the planar light source device 40 is disposed below the color liquid crystal display device 10 . Fig. 26A shows the arrangement of light emitting diodes 41 containing R light emitting diodes 41R, G light emitting diodes 41G and B light emitting diodes 41B in the planar light source device 40, and Fig. 26B shows the planar light source device 40 and liquid crystal A partial cross-sectional view of the color liquid crystal display device components of the display device 10 . The light source includes light emitting diodes 41 driven according to a pulse width modulation (PWM) control method. The luminance of the planar light source unit 42 is raised or lowered by raising or lowering the duty ratio in PWM control performed for the light emitting diodes 41 used in the planar light source unit 42 .

As shown in a partial sectional view in FIG. 26B , the planar light source device 40 is constituted by a housing 51 including an outer frame 53 and an inner frame 54 . The ends of the color liquid crystal display device 10 are fixed by an outer frame 53 and an inner frame 54 so that it is sandwiched between the outer frame 53 and the inner frame 54 with spacers 55A and 55B in between. The positioning member 56 is provided between the outer frame 53 and the inner frame 54 so that the color liquid crystal display device 10 sandwiched between the outer frame 53 and the inner frame 54 will not be displaced. Inside the case 51 , and towards the top of the case 51 , the diffuser plate 61 is fixed to the inner frame 54 with the gasket 55C and the holder 57 in between. An optical functional sheet group having a diffusion sheet 62 , a prism sheet 63 and a polarization conversion sheet 64 is laminated on the diffusion plate 61 .

The reflection sheet 65 is disposed inside the casing 51 and faces the bottom of the casing 51 . The reflective sheet 65 is disposed with its reflective surface facing the diffusion plate 61, and is fixed to the lower surface 52A of the housing 51 with a fixing member (not shown). The reflective sheet 65 is composed of, for example, a silver reflection enhancement film having a structure in which a silver reflective film, a low-refractive-index film, and a high-refractive-index film are sequentially laminated on a sheet substrate. The reflection sheet 65 reflects light emitted from the plurality of light emitting diodes 41, or light reflected by the side surface 52B of the case 51 or by the fence 44 shown in FIG. 26A. In this way, R light, G light, and B light respectively emitted from the R light-emitting diode 41R, G light-emitting diode 41G, and B light-emitting diode 41B are mixed, so that white light with high color purity can be obtained as illumination light. The illumination light passes through the diffusion plate 61 and the optical function sheet group including the diffusion sheet 62 , the prism sheet 63 and the polarization conversion sheet 64 , and illuminates the color liquid crystal display device 10 from the rear surface.

Photodiodes 43R, 43G, and 43B as optical sensors are provided near the lower surface 52A of the housing 51 . The photodiode 43R is a photodiode provided with an R color filter to measure the light intensity of the R light; the photodiode 43G is a photodiode provided with a G color filter to measure the light intensity of the G light; the photodiode 43B is provided with a B filter to measure the B light The light intensity of the photodiode. A group of optical sensors (photodiodes 43R, 43G, and 43B) are provided in one planar light source unit 42 .

The arrangement of the light emitting diodes 41R, 41G and 41B is such that a plurality of light emitting diode units are arranged in the horizontal direction and the vertical direction, and each unit includes an R light emitting diode 41R emitting R light with a wavelength of, for example, 640 nm, a light emitting diode with an emission wavelength of, for example, 530 nm. The G light-emitting diode 41G emits G light, and the B light-emitting diode 41B emits B light having a wavelength of, for example, 450 nm.

The planar light source unit 42 may be separated from the planar light source device 40 by a barrier 44 that shields illumination light emitted from the planar light source unit 42 (more specifically, light emitted from the light emitting diode 41 ). The luminance of each planar light source unit 42 is not affected by adjacent planar light source units 42 .

As shown in FIGS. 24 and 25, the drive circuit for driving the planar light source device 40 and the color liquid crystal display device 10 on the basis of an input signal from an external source (display circuit) includes a planar light source device control circuit 70, a planar light source unit drive circuit 80, and a liquid crystal display device driving circuit 90. The planar light source device control circuit 70 and the planar light source unit drive circuit 80 perform on/off control of the R light emitting diode 41R, the G light emitting diode 41G, and the B light emitting diode 41B according to the PWM control method. The planar light source device control circuit 70 includes a calculation circuit 71 and a storage unit (memory) 72 . The planar light source unit driving circuit 80 includes a computing circuit 81, a storage unit (memory) 82, a light emitting diode (LED) driving circuit 83, a photoelectric control circuit 84, switching elements 85R, 85G, and 85B of field effect transistors (FETs), and a light emitting diode (LED) Drive power supply (constant current source) 86 . Known circuits can be used as the circuits constituting the planar light source device control circuit 70 and the planar light source unit drive circuit 80 . The liquid crystal display device drive circuit 90 for driving the color liquid crystal display device 10 includes a known circuit such as a timing controller 91 . The color liquid crystal display device 10 is provided with a gate driver and a source driver (both not shown) for driving the switching elements 32 of the TFTs constituting the liquid crystal cell. To control the light emitting conditions of the light emitting diodes 41R, 41G and 41B, the following feedback mechanism is constructed. The light emitting states of the light emitting diodes 41R, 41G and 41B in a specific image display frame are measured by the photodiodes 43R, 43G and 43B, respectively, and the outputs of the photodiodes 43R, 43G and 43B are input into the photo control circuit 84 . The photodiode control circuit 84 and calculation circuit 81 then convert the outputs of the photodiodes 43R, 43G, and 43B into data (signals) indicating the luminance and chromaticity of the light emitting diodes 41R, 41G, and 41B. This data is then transmitted to the LED driving circuit 83, and the LED driving circuit 83 controls the lighting conditions of the light emitting diodes 41R, 41G, and 41B in subsequent image display frames. Current detection resistors r _R , r _G , and r _B are inserted in series with the light-emitting diodes 41R, 41G, and 41B downstream of the light-emitting diodes 41R, 41G, and 41B, respectively. The operation of the light emitting diode driving power supply 86 is controlled by the LED driving circuit 83 to convert the current flowing into the current detecting resistors r _R , r _G and r _B into voltages so that the currents in the current detecting resistors r _R , r _G and r _B The voltage drop may be a predetermined value. Although only one LED driving power source (constant current source) 86 is shown in FIG. 25, a plurality of LED driving power sources 86 for driving the LEDs 41R, 41G, and 41B are provided.

As described above, the display area 11 including two-dimensionally arranged pixels is divided into P×Q display area units 12 . If the display state is expressed using rows and columns, the display area 11 is divided into display area units 12 of Q rows×P columns. Each display area unit 12 includes M×N pixels. If the display state is expressed using rows and columns, the display area unit 12 is divided into N rows×M columns of pixels. The R light-emitting sub-pixel (R sub-pixel), the G light-emitting sub-pixel (G sub-pixel), and the B light-emitting sub-pixel (B sub-pixel) may be collectively referred to as "R, G, and B sub-pixels." The R-emitting sub-pixel control signal, the G-emitting sub-pixel control signal, and the B-emitting sub-pixel control signal for controlling the operations of the R, G, and B sub-pixels (more specifically, controlling light transmittance (aperture ratio)) may be collectively referred to as are "R, G, and B control signals", and are externally input to the driving circuit to respectively drive the R light-emitting sub-pixel input signal, the G light-emitting sub-pixel input signal, and the light-emitting sub-pixel input signal of the R, G, and B sub-pixels constituting the display area unit 12. The B photo sub-pixel input signals may be collectively referred to as "R, G and B input signals". As a transmission method of an input signal, a low voltage differential signaling (LVDS) method may be used. In the LVDS method, parallel signals are converted into low-voltage differential serial signals, and then the converted serial signals are transmitted. In this way, noise and extraneous emissions can be reduced, and the number of transmission lines can also be reduced. However, the signal transmission method is not limited to the LVDS method, and other methods such as a low-voltage transistor-transistor logic (LVTTL) method may also be employed.

A group of R, G, and B sub-pixels constitutes one pixel. In the following description of the respective embodiments, luminance control (gradation control) for each R, G, and B sub-pixel is performed in 2 ⁸ (0 to 255) steps by 8-bit control. Thus, each of the R, G and B input signals x R , x G and _x B input to the liquid crystal display driving circuit 90 to respectively drive the _R , _G and B sub-pixels constituting each pixel also takes 2 ⁸ (0 to 255) level. Each of the PWM output signals S _R , S _G and S _B for respectively controlling the emission times of the R light-emitting diode 41R, the G light-emitting diode 41G and the B light-emitting diode 41B also takes 2 ⁸ (0 to 255) levels. However, the control method is not limited to 8-bit control, but may be 10-bit control in 2 ¹⁰ (0 to 1023) stages, and in this case, the 8-bit value can be increased by 4 times.

A control signal for controlling the light transmittance Lt of each pixel is supplied from the driving circuit to the corresponding pixel. More specifically, R, G, and B control signals for controlling the light transmittance Lt of the R, G, and B sub-pixels are supplied from the liquid crystal display device drive circuit 90 to the R, G, and B sub-pixels, respectively. That is, the liquid crystal display device drive circuit 90 generates R, G, and B control signals from the R, G, and B input signals, respectively, and supplies (outputs) the generated R, G, and B control signals to the R, G, and B signals, respectively. sub-pixel. If necessary, the light source luminance Y of the planar light source unit 42 is changed for each image display frame. Thus, the R, G, and B control signals are equal to the R, G, and B input signals x R , x G , and x B respectively by correcting the R, G, and B input signals x _R , x _G , and x _B to the power of 2.2 on the basis of changes in the luminance Y of the light source (i.e., x _R ^2.2 , x _G ^2.2 and x _B ^2.2 ) obtained X _R-corr , X _G-corr and X _B-corr . Then, the R, G, and B control signals are output from the timing controller 91 constituting the liquid crystal display device driving circuit 90 to the gate driver and the source driver of the color liquid crystal display driver 10 according to a known method, and then drive the switching elements constituting each sub-pixel 32. Thus, a desired voltage is applied to the first transparent electrode 24 and the second transparent electrode 34 constituting the liquid crystal cell, so that the light transmittance (aperture ratio) Lt of each sub-pixel can be controlled. In this case, since the values X _R-corr , X _G-corr , and X _B-corr of the R, G, and B control signals are larger, the light transmittance Lt of the R, G, and B sub-pixels becomes higher, And the luminance (display luminance y) of the display portion corresponding to the R, G, and B sub-pixels becomes higher. That is, the image (usually dot-like) formed by light passing through the R, G, B sub-pixels is brighter.

Control of display luminance y and light source luminance Y is performed for each image display frame in image display of the color liquid crystal display device 10 , each display area unit 12 , or each planar light source unit 42 . The operation of the color liquid crystal display device 10 and the operation of the planar light source device 40 in one image display frame can be synchronized.

first embodiment

In the first embodiment, a driving method for a liquid crystal display device module is described. Specific values of the respective parameters used in the first to ninth embodiments are defined as follows.

x _max = 256

k ₀ =0.125

k ₁ =0.9375

k ₁ ·x _max =240

k ₀ ·x _max =32

k ₂ =0.485

α ₀ =1.00

α ₁ =0.7

α ₂ =0.1

D _max = A duty ratio of 714cd/ ^m2 can be obtained in the display area unit of the color liquid crystal display device

D ₀ =D _max

D ₁ = A duty ratio of 500 cd/m ² can be obtained in the display area unit in a color liquid crystal display device

D ₂ = A duty ratio of 71cd/m ² can be obtained in the display area unit of a color liquid crystal display device

1 to 9 show the relationship between the value X of the control signal provided to the pixel and the brightness Y of the light source and the light transmittance (aperture ratio) Lt of the sub-pixel and the display brightness y in the first to ninth embodiments. . In FIGS. 1 to 9, the solid line represents the operation of the display area unit 12 and the planar light source unit 42 that realize the increased luminance; the dashed line represents the operation of the display area unit 12 and the planar light source unit 42 that do not realize the increased luminance ; while the single dotted line represents the shared operation of the display area unit 12 and the planar light source unit 42 realizing the enhanced luminance and the display area unit 12 and the planar light source unit 42 not realizing the enhanced luminance.

In the first embodiment, the control mode 1A and the control mode 2A are employed. A description will now be given of a driving method for a liquid crystal display device assembly according to a first embodiment with reference to FIGS. 10 and 15 . 10 shows the concept of the relationship among the light source luminance Y, the light transmittance (aperture ratio) and the display luminance y of each pixel of the planar light source device 40 in the control mode 1A. FIG. 15 is a flowchart illustrating a driving method for a liquid crystal display device assembly.

Firstly, step S100 is executed as follows. Input signals (R, G, and B input signals ( _xR , _xG , and _xB )) for one image display frame sent from a known display circuit such as a scan converter and a control signal CLK are first input to the planar light source In the device control circuit 70 and the liquid crystal display device drive circuit 90 (see FIG. 24 ). Alternatively, the input signal and the control signal are first input into the planar light source driving control circuit 70 and then output to the liquid crystal display device driving circuit 90 . These input signals are also referred to as "video signals". The R, G, and B input signals x _R , x _G , and x _B input into the planar light source device control circuit 70 are temporarily stored in a storage unit (memory) 72 . The R, G, and B input signals x _R , x _G , and x _B input into the liquid crystal display device driving circuit 90 are also temporarily stored in a storage unit (not shown) provided for the liquid crystal display device driving circuit 90 . The R, G, and B input signals are output from a photopickup tube to which an amount such as _{yin is} input, for example, from a broadcasting station, and are input into the planar light source device driving circuit 70 and the liquid crystal display device driving circuit 90 to A signal that controls the light transmittance of the corresponding pixel. The input signal can be represented by a function of the input light quantity y _in raised to the power of 0.45, that is, y _in ^0.45 .

Then, steps S110A and S110B are performed as follows. In the planar light source device drive circuit 70 , the calculation circuit 71 reads the input signal value x stored in the storage unit (memory) 72 . Then, in each display area unit 12, if the input signal value x for any pixel constituting the display area unit 12 is greater than or equal to a predetermined value (in the first embodiment, k·x _max ), then with The luminance of the planar light source unit 42 associated with the display _area unit 12 is controlled by the planar light source device control circuit 70 and the planar light source unit device circuit 80, so as to obtain an input signal ( More specifically, it is the pixel luminance in the case where a control signal corresponding to a value equal to x _U-max + k ₀ ·x _max ) is supplied to the pixel in the first embodiment.

More specifically, firstly, it is checked whether the input signal value x of any pixel constituting the p-th column and q-th row (first p=1 and q=1) display area unit 12 satisfies x≥k ₁ ·x _max (1 ) to express the conditions. More specifically, it is checked whether all the input signal values x _R , x G and x _B for the R, _G and B sub-pixels of any pixel constituting the display area unit 12 are greater than or equal to the upper limit threshold k ₁ ·x _max , namely , whether the input signal value k ₁ ·x _max satisfies the following conditions respectively:

x _R ≥k ₁ x _max (1-1)

x _G ≥k ₁ x _max (1-2)

x _B ≥ k ₁ ·x _max (1-3).

Step S110B (m=1, 2, . . . , M, and n=1, 2, .

Then, steps S120A and S120B are performed as follows. If the condition expressed by x≧k ₁ ·x _max (1) is satisfied, the input signal value is set to x _U-max . More specifically, if the conditions x _R ≥ k ₁ x _max (1-1), x _G ≥ k ₁ x _max (1-2) and x _B ≥ k ₁ x _max (1-3) are simultaneously satisfied, The corresponding input values are then respectively set to x _U-max(R) , x _U-max(G) and x _U-max(B) . Then, the luminance of the planar light source unit 42 associated with the display area unit 12 _that realizes the increased luminance is controlled by the planar light source device control circuit 70 and the planar light source unit drive circuit 80, so that it is possible to obtain The pixel luminance when the control signal corresponding to the input signal of _max +k ₀ ·x _max (2) is supplied to the pixel. More specifically, the luminance of the planar light source unit 42 associated with the display area unit 12 that realizes the enhanced luminance is controlled by the planar light source device control circuit 70 and the planar light source drive circuit 80, so that it can be obtained assuming a value equal to (x _U-max(R) +x _U-max(G) +x _U-max(B) )/3+k ₀ ·x _max (2') corresponding R, G and B input signals of R, G and B R, G, and B subpixel luminances in the case where control signals are supplied to the R, G, and B subpixels. That is, the luminance of the planar light source unit 42 is improved. It should be noted that the first term on the right side in Expression (2') is an integer, and if the value obtained by dividing the first term by 3 is not an integer, the first decimal place is rounded. It should also be noted that the second term on the right side in expression (2') is an integer, thus the coefficient k0 should be chosen such that k ₀ ·x _max is an integer.

That is, since the control mode 1A is adopted in the first embodiment, the light source luminance of the planar light source unit 42 is set to Y _max regardless of the input signal value x _U-max . Thus, the light transmittance (aperture ratio) of the pixel including the R, G, and B sub-pixels exhibiting the maximum luminance to which the control signal corresponding to the input signal value x _U-max is supplied is set so that the display luminance can be obtained. The value of degree y _max . More specifically, in the first embodiment, although the original light transmittance (aperture ratio) of the pixel is Lt[X/X _max ] when the input signal value is x, under the control of the drive circuit, for each image The display frame is corrected for light transmission to Lt _Mdfy . More specifically, when the input signal value is x _U-max , the light transmittance of the pixel is set as:

Lt[(x _U-max +K ₀ ·X _max )/(1+K ₀ )X _max ] (11).

More specifically, if x _U-max(R) =240, x _U-max(G) =255 and x _U-max(B) =250, then calculate (x _U-max(R) +x _U-max(G) +x _U-max(B) ). that is,

_xU-max =(240+255+250)/3+32=248+32=280.

Thus, the luminance of the planar light source unit 42 associated with the display area unit 12 is controlled by the planar light source device control circuit 70 and the planar light source unit drive circuit 80, so that _R The pixel luminance in the case where the R, G and B control signals corresponding to the , G and B input signals are provided to the R, G and B sub-pixels, respectively.

Now suppose Y _max is 1.125 and Y _std is 1.000. In this case, the R, G, and B control signals corresponding to the R, G, and B input signals having a value equal to x _U-max = 280 are provided to the R, G, and B subpixels respectively. G and B sub-pixel luminance y ₂₈₀ can be expressed according to formula (11):

y ₂₈₀ =Y _max **Lt[280/288]

The luminance y of the R, G and B subpixels assuming that R, G and B control signals corresponding to R, G and B input signals of value equal to x=248 are supplied to the R, G and B subpixels ₂₄₈ can be expressed by the following formula:

y ₂₄₈ =Y _Std **Lt[248/256]

Therefore, y ₂₈₀ /y ₂₄₈ =1.129.

A pixel can be obtained under the assumption that R, G and B control signals corresponding to R, G and B input signals having a value equal to (1+k ₀ )x _max =288 are provided to the R, G and B sub-pixels, respectively The luminance load ratio D ₀ can be expressed by the following formula:

D ₀ =α ₀ ·D _max (4)

More specifically, the calculation circuit 71 of the planar light source device control circuit 70 determines the PWM output signal S for obtaining the luminance Y _max (the PWM output signal S R for controlling the light emitting time of the R light emitting diode 41R, the PWM output signal S _R for controlling the light emitting diode 41R, The PWM output signal S _G for the light-emitting time of the G light-emitting diode 41G, and the PWM output signal S _B for controlling the light-emitting time of the B light-emitting diode 41B).

Then, the PWM output signals _SR , _SG , and _SB determined in the calculation circuit 71 are output to the storage unit 82 of the planar light source unit driving circuit 80 provided for the planar light source unit 42, and are stored in the storage unit 82 . The clock signal CLK is also output to the planar light source unit driving circuit 80 (see FIG. 25 ).

Then, steps S120C and S120D are performed as follows. According to the control mode 2A in the first embodiment, if the calculation circuit 71 determines that the expression (1) is not satisfied in the display area unit 12 (or the expressions (1-1), (1-2) and (1-3) are satisfied simultaneously ), the light source luminance of the planar light source unit 42 that does not achieve improved luminance is set to Y _Std for each image display frame as in the related art. The light transmittance (aperture ratio) of the pixel is not changed or corrected. The light source luminance Y _Std is constant regardless of the value of the input signal. More specifically, the PWM output signal S for obtaining the light source luminance Y _Std of the planar light source unit 42 for each image display frame (the PWM output signal S _R for controlling the lighting time of the R light emitting diode 41R, for controlling The PWM output signal S _G of the light emitting time of the G light emitting diode 41G and the PWM output signal S _B for controlling the light emitting time of the B light emitting diode 41B are output to the planar light source unit drive circuit 80 provided for the planar light source unit 42 storage unit 82 (see FIG. 25 ), and are stored in the storage unit 82.

Steps S110A to S120D are repeated from p=1 to p=P and from q=1 to q=Q. An image display frame can then be displayed.

Then, step S130A is executed. Calculation circuit 81 determines the turn-on time t _R-ON and turn-off time t R-OFF of R light-emitting diode 41R and the turn-on time t _R-OFF of G light-emitting diode 41G on the basis of PWM output signals S _R , S _G and S _B respectively. _G-ON and turn-off time t _G-OFF , turn-on time t _B-ON and turn-off time t _B-OFF of the B light emitting diode 41B. The relationship between the turn-on time and the turn-off time of the light emitting diodes 41R, 41G, and 41B can be expressed by the following equation:

t _R-ON +t _R-OFF ＝t _G-ON +t _G-OFF ＝t _B-ON +t _B-OFF

= constant value t _Const .

The duty ratio in PWM driving for the light emitting diodes 41R, 41G, and 41B can be expressed by the following equation:

t _ON /(t _ON +t _OFF )＝t _ON /t _Const

Then, step S130B is performed as follows. The turn-on times t _{R-ON , t G-ON} and t _{B- ON} of the R light-emitting diode 41R, the G light-emitting diode 41G and the B light-emitting diode 41B respectively are sent to the LED driving circuit 83 . Then, based on signals indicative of on-times t _R-ON , t _G-ON and t _B-ON , switching elements 85R, 85G and 85B are turned on respectively for on-times t _R-ON , t _G-ON and t _B-ON , and the LED driving current is output from the LED driving power supply 86 and flows into the LEDs 41R, 41G, and 41B. Accordingly, in one image display frame, the LEDs 41R, 41G, and 41B emit light for a time period equal to the on-times t _R-ON , t _G-ON , and t _{B-ON ,} respectively. As a result, the display area unit 12 in the pth column and qth row is illuminated with a predetermined luminance, so that one image display frame can be displayed. In one image display frame, the operation of the liquid crystal device 10 and the operation of the planar light source device 40 are synchronized.

Steps S140A to S140D are then performed as follows. The R, G, and B input signals _xR , _xG , and _xB input to the liquid crystal display circuit 90 are sent to the timing controller 91, and the timing controller 91 outputs the signals corresponding to R, G, and R to the R, G, and B subpixels, respectively. R, G, and B control signals corresponding to the B input signal. The relationship between the R, G and B control signals x _R , x _G and x _B generated in the timing controller 91 and provided to the R, G and B sub-pixels respectively and the R, G and B input signals respectively can be given by the formula (21-1), (21-2) and (21-3) expression:

X _R ＝ f _R (b _{1_R} x _R ^2.2 +b _{0_R} )(21-1)

X _G ＝f _G (b _{1_G} x _G ^2.2 +b _{0_G} )(21-2)

X _B ＝f _B (b _{1_B} x _B ^2.2 +b _{0_B} )(21-1)

Among them, b _{1_R} , b _{0_R} , b _{1_G} , b _{0_G} , b _{1_B} and b _{0_B} are constants, while f _R , f _G and f _B are used for correction based on the control of the luminance of the light source if necessary R. The G and B control signals x _R , x _G and x _B are predetermined functions.

The resulting operation of the display area unit 12 and the planar light source unit 42 is indicated by the solid and dashed lines in FIG. 1 . It should be noted that, as described above, the control signal X in FIGS. 1 to 9 is obtained by correcting the value x ^2.2 (x≡x ^2.2 ) of the input signal x input to the liquid crystal display device driving circuit 90 to drive each sub-pixel .

The coefficient k ₀ in k ₀ x _max in the second term on the right side of formula (2) or (2') can be the linear function F _{_k0} (x _Ave ) or the average value [(x _{U- max(R)} +x _U-max(G) +x _U-max(B) )/3=x _Ave ] is a function F _{_k0} (x _Ave ) expressed by a high-order polynomial. For example, the function F _{_k0} (x _Ave ) can be expressed by the formula F _{_k0} (x _Ave )=k ₀ ·x _ave /{(1-k ₁ )·x _max }-k ₀ ·k ₁ /(1-k ₁ ) A linear function of x _ave expressed. The function F _{_k0} (x _Ave ) is a linear function indicating 0 when x _Ave =k ₁ ·x _max and indicating k ₀ when x _Ave =x _max . It applies to subsequent examples. The relationship between the control signal value X supplied to the pixel, the light transmittance (aperture ratio) Lt, and the display luminance y of the sub-pixel is shown by the dotted line in FIG. 1 .

second embodiment

In the second embodiment which is a modification of the first embodiment, the control mode 1B and the control mode 2A are employed. That is, in steps S220A and S220B similar to steps S120A and S120B in the first embodiment, the control mode 1B is employed. In the second embodiment, the relationship between the control signal value X and the luminance Y of the light source, the light transmittance Lt of the sub-pixel and the display luminance y is shown in FIG. 2 . A description will now be given of a driving method for a liquid crystal display device assembly according to a second embodiment with reference to FIGS. 11A and 11B and 16 . 11A and 11B show the concept of the relationship among the light source luminance, light transmittance (aperture ratio), and display luminance of pixels of the planar light source device 40 in the control mode 1B. FIG. 16 is a flowchart illustrating a driving method for a liquid crystal display device assembly.

In step S200, step S100 in the first embodiment is executed. Then, in steps S210A and S210B, steps S110A and S110B are performed.

In the second embodiment, in steps S220A and S220B, the luminance of the planar light source unit 42 realizing increased luminance is increased according to an increase in the input signal value xU _-max . More specifically, in the second embodiment, the light source luminance Y _Mdfy is set under the control of the planar light source device control circuit 70 and the planar light source unit drive circuit 80 when the light transmittance is Lt[X _U-max /X _max ], the value of display luminance y _max can be obtained for each image display frame. (see formula (12)).

Y _Mdfy **Lt[X _U-max /X _max ]

=Y _max **Lt[(X _U-max +K ₀ ·X _max )/(1+K ₀ )X _max ] (12)

In the second embodiment, although the light source luminance Y _Mdfy of the display area unit 12 is controlled, the light transmittance (aperture ratio) of the pixels constituting the display area unit 12 is not changed or corrected. That is, when the input signal value is x, the light transmittance of the pixel is Lt[X/X _max ].

If the calculation circuit 71 determines that there is no pixel satisfying the expression (1) (or simultaneously satisfying the expressions (1-1), (1-2) and (1-3)) in the display area unit 12, then the processing in the first embodiment is performed. Steps S120C and S120D as steps S220C and S220D.

Then, steps S130A and S130B in the first embodiment are executed as steps S230A and S230B.

Then, steps S140A, S140C, and S140D are performed as steps S240A, S240C, and S240D. In the second embodiment, step S240B is to control the luminance of the light source based on the value x ^2.2 (x≡x ^2.2 ) of the input signal x input to the liquid crystal display device driving circuit 90 to drive each sub-pixel Correction is unnecessary.

The configuration and structure of the liquid crystal display device assembly in the second embodiment are similar to those in the first embodiment, and thus description thereof will be omitted.

third embodiment

In the third embodiment also as a modification to the first embodiment, the control mode 1C and the control mode 2A are employed. That is, in steps S320A and S320B similar to steps S120A and S120B in the first embodiment, control mode 1C is adopted. In the third embodiment, the relationship between the control signal value X and the luminance Y of the light source, the light transmittance Lt of the sub-pixel and the display luminance y is shown in FIG. 3 . A description will now be given of a driving method for a liquid crystal display device assembly according to a third embodiment with reference to FIGS. 12A and 12B and 17. FIG. 12A and 12B show the light source luminance of the planar light source device 40 of the pixel in the control mode 1C, and the relationship between the light transmittance (aperture ratio) of the pixel and the display luminance y. FIG. 17 is a flowchart showing a driving method for a liquid crystal display device assembly.

In step S300, step S100 in the first embodiment is executed. Then, in steps S310A and S310B, steps S110A and S110B are executed.

In the third embodiment, in steps S320A and S320B, regardless of the input signal value _xU-max , the light transmittance of the pixel exhibiting the maximum luminance (pixel A) constituting the display area unit 12 realizing the enhanced luminance (aperture ratio) are all set to a constant value Lt _max , and the planar light source unit 42 is controlled to obtain a desired display luminance. More specifically, in the third embodiment, the light source luminance Y _Mdfy is set under the control of the planar light source device control circuit 70 and the planar light source unit drive circuit 80 so that it can be displayed for each image when the light transmittance is Lt _max . The frame gets the value of display luminance y _max (see equation (13)).

Y _Mdfy **Lt _max

=Y _max **Lt[(X _U-max +K ₀ ·X _max )/(1+K ₀ )X _max ] (13)

In the third embodiment, the light source luminance Y _Mdfy of the planar light source unit 42 is controlled, and the light transmittance (aperture ratio) of the pixels constituting the display area unit 12 is also corrected.

If the calculation circuit 71 determines that there is no pixel satisfying the expression (1) (or simultaneously satisfying the expressions (1-1), (1-2) and (1-3)) in the display area unit 12, then the processing in the first embodiment is performed. Steps S120C and S120D as steps S320C and S320D.

Then, steps S130A and S130B in the first embodiment are executed as steps S330A and S330B.

Then, steps S140A to S140D are performed as steps S340A to S340D.

The configuration and structure of the liquid crystal display device assembly in the third embodiment are similar to those in the first embodiment, and thus description thereof will be omitted.

Fourth embodiment

In the fourth embodiment, another driving method for a liquid crystal display device module will be described below. More specifically, in the fourth embodiment, the control mode 1A and the control mode 2B are employed. The relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the pixel and the display luminance y in the fourth embodiment is shown in FIG. 4 . A description will now be given of a driving method for a liquid crystal display device assembly according to a fourth embodiment with reference to FIGS. 13A and 13B and 18. FIG. 13A and 13B show the relationship between the light source luminance of the planar light source device 40 and the light transmittance (aperture ratio) of the pixel and the display luminance in the control mode 2B. FIG. 18 is a flowchart illustrating a driving method for a liquid crystal display device assembly.

In step S400, step S100 in the first embodiment is executed. Then in steps S410A and S410B, steps S110A and S110B are executed. Then, in steps S420A and S420B, steps S120A and S120B are performed.

Steps S420C and S420D are different from steps S120C and S120D in the first embodiment. If the calculation circuit 71 determines that there is no pixel satisfying the expression (1) (or simultaneously satisfying the expressions (1-1), (1-2), and (1-3)) in the display area unit 12, then the luminance of the improvement is not achieved. The luminance of the display area unit 12 corresponding to the planar light source unit 42 is controlled by the planar light source device control circuit 70 and the planar light source unit drive circuit 80, so that the display area unit can be driven under the assumption that it has an indication input into the drive circuit. 12 The maximum value x' of the maximum value of the input signals of all pixels is the pixel luminance in the case where the input signal corresponding to _U-max is supplied to the pixel.

More specifically, when any of the input signal values x _R , x _G , and x _B for all pixels constituting a display area unit 12 is smaller than a predetermined value k ₁ ·x _max , the planar light source unit corresponding to the display area unit 12 The luminance of 42 is controlled by the planar light source device control circuit 70 and the planar light source unit drive circuit 80, so that it is assumed that the control signal corresponding to the input signal having the maximum value x' _U-max is provided to the R, G and B sub-units. R, G, and B subpixel intensities in the case of a pixel.

In the fourth embodiment, since the control mode 2B is employed, regardless of the input signal value x′ _U-max , the light constituting the pixel exhibiting the maximum luminance (pixel B) of the display area unit 12 that does not realize enhanced luminance The transmittance (aperture ratio) is set to a constant value Lt _max , and the planar light source unit 42 is controlled so that a desired display luminance can be obtained. More specifically, in the fourth embodiment, the light source luminance Y _Mdfy under the control of the planar light source drive control circuit 70 and the planar light source unit drive circuit 80 is set to be able to display for each image when the light transmittance is Lt _max The frame obtains the value of display luminance _y'max (see formula (14)).

Y _Mdfy **Lt _max

=Y _Std **Lt[(X' _U-max /X _max ] (14)

In the fourth embodiment, the light source luminance Y _Mdfy of the planar light source unit 42 that does not realize enhanced luminance is controlled, and the light transmittance (aperture ratio) of the pixels constituting the display area unit 12 that does not realize enhanced luminance is also corrected.

More specifically, the PWM output signal S for obtaining the light source luminance Y _Mdfy of the planar light source unit 42 for each image display frame (the PWM output signal S _R for controlling the lighting time of the R light emitting diode 41R, for controlling The PWM output signal S _G of the light emitting time of the G light emitting diode 41G, the PWM output signal S _B for controlling the light emitting time of the B light emitting diode 41B) are sent to the planar light source unit driving circuit 80 provided for the planar light source unit 42 storage unit 82 and is stored in storage unit 82 . The clock signal CLk is also output to the planar light source unit driving circuit 80 (see FIG. 25 ).

For example, when x _R =110, x _G =150, and x _B =50, x' _U-max =150. Correspondingly, the light source luminance Y _Mdfy of the planar light source unit 42 corresponding to the display area unit 12 that does not realize the enhanced luminance is controlled by the planar light source device control circuit 70 and the planar light source drive circuit 80, so that it can be obtained under assumptions R, G In the case where the light transmittance of the and B subpixels is set to Lt _max and control signals corresponding to the R, G and B input signals having a value equal to x' _U-max = 150 are supplied to the R, G and B subpixels The R, G, and B subpixels display luminance y' _max .

In the fourth embodiment, it can be obtained that under the assumption that the R, G and B control signals corresponding to the R, G and B input signals having a value equal to k ₁ ·x _max are supplied to the R, G and B sub-pixels respectively The duty ratio _D1 of pixel luminance is expressed by the following formula:

D ₁ =α ₁ ·D _max (5)

where D _max represents the maximum load ratio.

Then, steps S130A and S130B in the first embodiment are executed as steps S430A and S430B.

Then, steps S140A to S140D are executed as steps S440A to S440D.

The configuration and structure of the liquid crystal display device assembly in the fourth embodiment are similar to those in the first embodiment, and thus description thereof will be omitted.

fifth embodiment

In the fifth embodiment which is a modification of the fourth embodiment, control mode 1A, control mode 2B, and control mode 2C are employed. That is, in steps S520C and S520D similar to steps S420C and S420D, the control mode 2B and the control mode 2C are adopted. The relationship between the control signal value X and the light source luminance Y, and the light transmittance Lt of the pixel and the display luminance y in the fifth embodiment is shown in FIG. 5 . A description will now be given of a driving method for a liquid crystal display device assembly according to a fifth embodiment with reference to FIGS. 14 and 19 . FIG. 14 shows the concept of the relationship between the light source luminance of the planar light source device 40 and the light transmittance (aperture ratio) of the pixel and the display luminance in the control mode 2C. FIG. 19 is a flowchart showing a driving method for a liquid crystal display device assembly.

In step S500, step S100 in the first embodiment is executed. Then, in steps S510A and S510B, steps S110A and S110B are performed. Then, in steps S520A and S520B, steps S120A and S120B are performed.

Steps S520C and S520D are different from steps S420C and S420D in the fourth embodiment. If the calculation circuit 71 determines that there is no pixel satisfying the formula (1) (or satisfying the formulas (1-1), (1-2) and (1-3) simultaneously) in the display area unit 12, then the luminance that does not satisfy the increased The luminance of the planar light source unit 42 corresponding to the display area unit 12 is controlled by the planar light source device control circuit 70 and the planar light source unit control circuit 80, so that it can be obtained under the assumption that there is an instruction input into the drive circuit to drive the configuration without realizing improvement. The luminance of the display area unit 12 is the maximum value x' of the maximum value of the input signals of all pixels of the pixel _U-max when the control signal corresponding to the input signal is supplied to the pixel.

However, in the fifth embodiment, it is determined in step S520E whether the value x′ _U-max is smaller than or equal to k ₂ ·x _max (ie, x′ _U-max ≤ _{k 2} ·x _max (3)). If formula (3) is satisfied, the luminance of the planar light source unit 42 corresponding to the display area unit 12 that does not realize the enhanced luminance is controlled by the planar light source device control circuit 70 and the planar light source unit drive circuit 80, thereby obtaining Pixel luminance in case a control signal corresponding to an input signal having a value equal to x' _U-max /k ₂ (or x' _U-max /{(k ₂ x _max )/x _max }) is supplied to the pixel .

In the fifth embodiment, regardless of the input signal value x' _U-max of the input signal satisfying the expression (3), the planar light source corresponding to the display area unit 12 that does not realize the enhanced luminance and satisfies the expression (3) The light source luminances of the cells 42 are all set to a constant value Y". In this case, the light transmittance Lt _Mdfy of the pixel (pixel B) constituting the display area unit 12 exhibiting the maximum luminance is set so that the display luminance can be obtained. Degree y" _max value. More specifically, when the input signal value is x, the original light transmittance (aperture ratio) of the pixel is Lt[X/X _max ]. However, in the fifth embodiment, under the control of the planar light source device control circuit 70 and the planar light source unit control circuit 80, the light transmittance of the pixel is corrected to Lt _Mdfy for each image display frame. More specifically, when the input signal value is x' _U-max , the light transmittance of the pixel is set as:

Lt[X' _U-max /{(K ₂ ·X _max )/X _max }] (15)

In the fifth embodiment, the light source luminance of the planar light source unit 42 that does not realize enhanced luminance is controlled to be Y", and the light transmittance (aperture ratio) of the pixels constituting the display area unit 12 that does not realize enhanced luminance ) is also corrected.

More specifically, the PWM output signal S for obtaining the light source luminance Y" of the planar light source unit 42 for each image display frame (the PWM output signal S _R for controlling the lighting time of the R light emitting diode 41R, for controlling The PWM output signal S _G of the light emitting time of the G light emitting diode 41G, the PWM output signal S _B for controlling the light emitting time of the B light emitting diode 41B) are sent to the planar light source unit driving circuit 80 provided for the planar light source unit 42 The storage unit 82 is stored in the storage unit 82. The clock signal CLK is also output to the planar light source unit driving circuit 80 (see FIG. 25 ).

For example, when x _R =10, x _G =15, and x _B =5, x' _U-max =15. Accordingly, the luminance of the planar light source unit 42 that does not achieve improved luminance is set to Y", and the light transmittance of the R, G, and B sub-pixels is corrected to Lt[15/(0.2×256)/256] .

A duty ratio D of pixel luminance can be obtained assuming that R, G, and B control signals corresponding to R, G, and B input signals having a value equal to k ₂ ·x _max are supplied to R, G, and B subpixels ₂ is expressed by the following formula:

D ₂ =α ₂ ·D _max (6)

where D _max represents the maximum load ratio.

Then, steps S130A and S130B in the first embodiment are executed as steps S530A and S530B.

Then, steps S140A to S140D are performed as steps S540A to S540D.

The configuration and structure of the liquid crystal display device assembly in the fifth embodiment are similar to those in the first embodiment, and thus description thereof will be omitted.

Sixth embodiment

In the sixth embodiment which is a modification of the fourth and second embodiments, the control mode 1B and the control mode 2B are employed. That is, in steps S620A and S620B similar to steps S120A and S120B in the first embodiment, the control mode 1B is adopted. The relationship between the control signal value X and the luminance Y of the light source, the light transmittance Lt of the sub-pixel and the display luminance y in the sixth embodiment is shown in FIG. 6 . A description will now be given of a driving method for a liquid crystal display device assembly according to a sixth embodiment with reference to FIG. 20 .

In step S600, step S100 in the first implementation is executed. Then, in steps S610A and S610B, steps S110A and S110B in the first embodiment are executed. Then, in steps S720A and S720B, steps S220A and S220B in the second embodiment are executed.

If the calculation circuit 71 determines that there is no pixel satisfying the expression (1) (or simultaneously satisfying the expressions (1-1), (1-2) and (1-3)) in the display area unit 12, the Steps S420C and S420D serve as steps S620C and S620D.

Then, steps S130A and S130B in the first embodiment are executed as steps S630A and S630B.

Then, steps S140A to S140D in the first embodiment are executed as steps S640A to S640D.

The configuration and structure of the liquid crystal display device assembly in the sixth embodiment are similar to those in the first embodiment, and thus description thereof will be omitted.

Seventh embodiment

In the seventh embodiment which is a modification of the sixth embodiment, control mode 1B, control mode 2B, and control mode 2C are employed. That is, in steps S720C and S720D similar to steps S420C and S420D in the fourth embodiment, the control mode 2B and the control mode 2C are adopted. The relationship between the control signal value X and the luminance Y of the light source, the light transmittance Lt of the sub-pixel and the display luminance y in the seventh embodiment is shown in FIG. 7 . A description will now be given of a driving method for a liquid crystal display device assembly according to a seventh embodiment with reference to FIG. 21. FIG.

In step S700, step S100 in the first embodiment is executed. Then, in steps S710A and S710B, steps S110A and S110B in the first embodiment are executed. Then, in steps S720A and S720B, steps S220A and S220B in the second embodiment are executed.

If the calculation circuit 71 determines that there is no pixel satisfying the expression (1) (or simultaneously satisfying the expressions (1-1), (1-2) and (1-3)) in the display area unit 12, then the Steps S520C to S520G are taken as steps S720C to S720G.

Then, steps S130A and S130B in the first embodiment are executed as steps S730A and S730B.

Then, steps S140A to S140D are executed as steps S740A to S740D.

The configuration and structure of the liquid crystal display device assembly in the seventh embodiment are similar to those in the first embodiment, and thus description thereof will be omitted.

Eighth embodiment

In the eighth embodiment which is a modification of the fourth and third embodiments, the control mode 1C and the control mode 2B are employed. That is, in steps S820A and S820B similar to steps S120A and S120B in the first embodiment, control mode 1C is employed. The relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the sub-pixel and the display luminance y in the eighth embodiment is shown in FIG. 8 . A description will now be given of a driving method for a liquid crystal display device assembly according to an eighth embodiment with reference to FIG. 22 .

In step S800, step S100 in the first embodiment is executed. Then, in steps S810A and S810B, steps S110A and S110B are performed. Then, in steps S820A and S820B, steps S320A and S320B in the third embodiment are executed.

If the calculation circuit 71 determines that there is no pixel satisfying the expression (1) (or simultaneously satisfying the expressions (1-1), (1-2) and (1-3)) in the display area unit 12, then the calculation in the fourth embodiment is performed. Steps S420C and S420D as steps S820C and S820D.

Then, steps S130A and S130B in the first embodiment are executed as steps S830A and S830B.

Then, steps S140A to S140D in the first embodiment are executed as steps S840A to S840D.

The configuration and structure of the liquid crystal display device assembly in the eighth embodiment are similar to those in the first embodiment, and thus description thereof will be omitted.

Ninth embodiment

In the ninth embodiment which is a modification of the eighth embodiment, control mode 1C, control mode 2B, and control mode 2C are employed. That is, in steps S920C and S920D similar to steps S420C and S420D in the fourth embodiment, the control mode 2B and the control mode 2C are adopted. The relationship between the control signal value X and the luminance Y of the light source and the light transmittance Lt of the sub-pixel and the display luminance y in the ninth embodiment is shown in FIG. 9 . A description will now be given of a driving method for a liquid crystal display device assembly according to a ninth embodiment with reference to FIG. 23 .

In step S900, step S100 in the first embodiment is executed. Then, in steps S910A and S910B, steps S110A and S110B in the first embodiment are executed. Then, in steps S920A and S920B, steps S320A and S320B in the third embodiment are executed.

If the calculation circuit 71 determines that there is no pixel satisfying the expression (1) (or simultaneously satisfying the expressions (1-1), (1-2) and (1-3)) in the display area unit 12, then the Steps S520C to S520G of the present invention serve as steps S920C to S920G of the ninth embodiment.

Then, steps S130A and S130B in the first embodiment are executed as steps S930A and S930B.

Then, steps S140A to S140D in the first embodiment are executed as steps S940A to S940D.

The configuration and structure of the liquid crystal display device assembly in the ninth embodiment are similar to those in the first embodiment, and thus description thereof will be omitted.

The present invention has been discussed by way of illustration of preferred embodiments, but the invention is not limited to the disclosed embodiments. The configurations and structures of the color liquid crystal display device assembly, the transmissive type color liquid crystal display device, and the planar light source device are only examples, and the components and materials constituting these devices are also only examples and can be appropriately changed. For example, luminance correction or temperature control for a planar light source unit can be performed as follows. The light-emitting condition of the planar light source device is monitored by the optical sensor, and the temperature of the light-emitting diode is monitored by the temperature sensor, and then the monitoring result is fed back to the LED driving circuit 83 .

In addition, if (x _U-max(R) +x _U-max(G) +x _U-max(B) )/3≥k ₁ x _max (1”) is satisfied to replace formula (1-1), (1-2) and (1-3), then the luminance of the planar light source unit 42 corresponding to the display area unit 12 can be controlled by the drive circuit, so as to obtain a value equal to (x _U-max(R) +x The control signal corresponding to the input signal of _U-max(G) +x _U-max(B) )/3+k ₀ x _max (k ₀ is a coefficient in the range expressed by 0.06≤k ₀ ≤0.03) is The R, G, and B subpixel luminances provided to the R, G, and B subpixels.

It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and changes may occur depending on design needs and other factors, but they still fall within the scope of the appended claims and their equivalent technical solutions.

Claims (19)

1. A driving method for a liquid crystal display device assembly, said liquid crystal display device assembly comprising: (A) a transmissive liquid crystal display device comprising a display area where pixels are arranged in a two-dimensional matrix, (B) comprising a virtual P For a planar light source device with P×Q planar light source units corresponding to ×Q display area units, when the display area of the transmissive liquid crystal display device is divided into the virtual P×Q display area units, the a planar light source device illuminating the display area unit corresponding to the planar light source unit from the rear surface of the display area unit, and (C) a driving circuit for driving the planar light source device and the transmissive liquid crystal display device, the The driving circuit provides each pixel with a control signal for controlling the light transmittance of the pixel, and the driving method includes the following steps: In the case where the value of the input signal input to the driving circuit for driving the pixel is represented by x, in each of the display area units, when any pixel constituting the display area unit The value x of the input signal is greater than or equal to a predetermined value, wherein when the value of the input signal is represented by x _U-max , the luminance of the planar light source unit corresponding to the display area unit is controlled by the drive circuit, so that The luminance of a pixel can be obtained if a control signal corresponding to an input signal having a value greater than xU _-max is supplied to the pixel. 2. The driving method according to claim 1, wherein the maximum value of the input signal used to drive the pixel in the driving circuit is represented by x _max , and the predetermined value is represented by k ₁ x _max represents, where k ₁ is a coefficient in the range 0.94 ≤ k ₁ ≤ 0.99, in each said display area unit, when the input for any pixel constituting said display area unit The value x of the signal is greater than or equal to k ₁ ·x _max , wherein when the value of the input signal is represented by x _U-max , the luminance of the planar light source unit corresponding to the display area unit is controlled by the drive circuit , thus obtaining the case where a control signal corresponding to an input signal having a value equal to x _U-max +k ₀ ·x _max is supplied to the pixel, where k ₀ is a coefficient in the range 0.06≤k ₀ ≤0.3 The brightness of the pixel below. 3. The driving method according to claim 1, wherein each pixel comprises a group of three sub-pixels, the three sub-pixels are red light emitting sub-pixels, green light emitting sub-pixels and blue light emitting sub-pixels, and The values of the input signals for driving the red light-emitting sub-pixel, the green light-emitting sub-pixel and the blue light-emitting diode in the driving circuit are represented by x _R , x _G and x _B respectively, and in The maximum value of the input signal input into the driving circuit to drive the pixel is denoted by x _max , and the predetermined value is denoted by k ₁ ·x _max , where k ₁ is in the range of 0.94≤k ₁ ≤0.99 In the case of coefficients of , in each of said display area units, when all values x _R , x _G , and x _B used for any pixel constituting said display area unit are greater than or equal to k ₁ ·x _max , When the values of the input signals are represented by _xU-max(R) , _xU-max(G) and _xU-max(B) respectively, the planar light source unit corresponding to the display area unit is controlled by the drive circuit , so that a control signal corresponding to an input signal having a value equal to (x _U-max(R) +x _U-max(G) +x _U-max(B) )/3+k0 x _max are provided to red-emitting sub-pixels, green-emitting sub-pixels and blue-emitting sub-pixels, where k ₀ is a coefficient in the range of 0.06 ≤ k ₀ ≤ 0.3. Subpixel luminance. 4. The driving method according to claim 1, wherein the planar light source unit comprises a light emitting diode. 5. The driving method according to claim 4, wherein the luminance of the planar light source unit is used in the pulse width modulation control of the light emitting diodes constituting the planar light source unit by increasing or decreasing The load ratio is increased or decreased. 6. The driving method as claimed in claim 5, characterized in that, in the case where the maximum value of the input signal for driving the pixel inputted into the driving circuit is represented by _xmax , the AND value can be obtained A control signal corresponding to an input signal equal to (1+k ₀ )x _max is supplied to the pixel, where k ₀ is the duty ratio D of the pixel luminance for a coefficient in the range 0.06≤k ₀ ≤0-3 ₀ is expressed by D ₀ =α ₀ ·D _max , where α ₀ is a coefficient in the range of 0.95≦α ₀ ≦1.0, and D _max represents the maximum duty ratio. 7. The driving method according to claim 1, further comprising the steps of: In each of the display area units, if the value x of the input signal for all the pixels constituting the display area unit is smaller than the predetermined value, the input signal used to drive the display area unit for driving the display area unit In the case where the maximum value of the input signals of all the pixels of the area unit is represented by x' _U-max , the luminance of the planar light source unit corresponding to the display area unit is controlled by the drive circuit, so as to obtain The pixel luminance in case a control signal corresponding to an input signal having a value equal to this maximum value x' _U-max is supplied to said pixel. 8. The driving method according to claim 7, wherein the maximum value of the input signal for driving the pixel inputted into the driving circuit is represented by x _max , and the predetermined value is represented by k ₁ ·x _max means, where k ₁ is a coefficient in the range of 0.94 ≤ k ₁ ≤ 0.99, in each of the display area units, when the value of the input signal for any pixel constituting the display area unit x is greater than or equal to k ₁ ·x _max , wherein when the value of the input signal is represented by x _U-max , the luminance of the planar light source unit corresponding to the display area unit is controlled by the drive circuit, so that Obtaining the pixel luminance in case a control signal corresponding to an input signal of value equal to x _U-max +k ₀ ·x _max is supplied to the pixel, where k ₀ is a coefficient in the range 0.06≤k ₀ ≤0.3 ,and In each of the display area units, the value x of the input signal for constituting any pixel of the display area unit is smaller than k ₁ ·x _max , and the input signal to the driving circuit for driving all the pixels constituting the display area unit In the case where the maximum value of the input signals of all pixels of the display area unit is represented by x' _U-max , the luminance of the planar light source unit corresponding to the display area unit is controlled by the drive circuit, so that The pixel luminance in case a control signal corresponding to an input signal having a value equal to said maximum value x' _U-max is supplied to the pixel. 9. The driving method according to claim 7, wherein each pixel comprises a group of three sub-pixels, the three sub-pixels are red light emitting sub-pixels, green light emitting sub-pixels and blue light emitting sub-pixels, and The values of the input signals used to drive the red light-emitting sub-pixels, green light-emitting sub-pixels and blue light-emitting diodes in the driving circuit are represented by x _R , x _G and x _B respectively, and are input to the The maximum value of the input signal for driving the pixel in the driving circuit is denoted by x _max , and the predetermined value is denoted by k ₁ ·x _max , where k ₁ is in the range of 0.94 ≤ k ₁ ≤ 0.99 In the case of coefficients, in each of said display area units, when all values x _R , x _G and x _B for any pixel constituting said display area unit are greater than or equal to k ₁ ·x _max , where When the values of the input signals are respectively represented by x _U-max(R) , x _U-max(G) and x _U-max(B) , the drive circuit controls the The luminance of the planar light source unit can be obtained at an input signal with a value equal to (x _U-max(R) +x _U-max(G) +x _U-max(B) )/3+k ₀ x _max Corresponding control signals are provided to the red light-emitting sub-pixel, the green light-emitting sub-pixel and the blue light-emitting sub-pixel, where k ₀ is the light emitting R in the case of a coefficient in the range of 0.06≤k ₀ ≤0.3 the luminance of the photo sub-pixel, the G-emitting sub-pixel and the B-emitting sub-pixel, and In each of the display area units, when any value x _R , x _G , and x _B for all the pixels constituting the display area unit is smaller than k ₁ ·x _max , and the value input to the driving circuit is When the maximum value of the input signals for the red light-emitting sub-pixel, the green light-emitting sub-pixel and the blue light-emitting sub-pixel for driving all the pixels constituting the display area unit is represented by x' _U-max , given by The drive circuit controls the luminance of the planar light source unit corresponding to the display area unit so that it is obtained when a control signal corresponding to an input signal having a value equal to the maximum value x' _U-max is supplied to the In the case of the red light-emitting sub-pixel, the green light-emitting sub-pixel and the blue light-emitting sub-pixel, the luminance of the red light-emitting sub-pixel, the green light-emitting sub-pixel and the blue light-emitting sub-pixel. 10. The driving method according to claim 7, wherein the planar light source unit comprises a light emitting diode. 11. The driving method according to claim 10, wherein the luminance of the planar light source unit is used in the pulse width modulation control of the light emitting diodes constituting the planar light source unit by increasing or decreasing The load ratio is increased or decreased. 12. The driving method according to claim 11, characterized in that, in the case where the maximum value of the input signal for driving the pixel inputted into the driving circuit is represented by _xmax , it can be obtained in the AND value A control signal corresponding to an input signal equal to (1+k ₀ )x _max is supplied to the pixel, where k ₀ is the duty ratio D ₀ of the pixel luminance for the case of a coefficient in the range 0.06≤k ₀ ≤0.3 given by D ₀ =α ₀ ·D _max expression, where α ₀ is a coefficient in the range of 0.95≦α ₀ ≦1.0, and D _max represents the maximum duty ratio. 13. The driving method according to claim 11, characterized in that, in the case where the maximum value of the input signal for driving the pixel inputted into the driving circuit is represented by _xmax , it can be obtained in the AND value A control signal corresponding to an input signal equal to k ₁ ·x _max is supplied to the pixel, where k ₁ is the duty ratio D ₁ of the pixel luminance in the case of a coefficient in the range 0.94≤k ₁ ≤0.99 by D ₁ = α ₁ ·D _max represents, where α ₁ is a coefficient in the range of 0.3≤α ₁ ≤0.8, and D _max represents the maximum duty ratio. 14. The driving method according to claim 7, wherein the maximum value of the input signal used to drive the pixel in the driving circuit is represented by x _max , and the maximum value x' _{U -max} is expressed by x' _U-max ≤ _{k 2} ·x _max , where k ₂ is a coefficient in the range of 0.35 ≤ k ₂ ≤ 0.5, all the corresponding to the display area unit are controlled by the drive circuit The luminance of the planar light source unit can be obtained so that the luminance of the pixel in the case where the control signal corresponding to the input signal having a value equal to x' _U-max /k ₂ is supplied to the pixel can be obtained. 15. The driving method according to claim 14, wherein the planar light source unit comprises a light emitting diode. 16. The driving method according to claim 15, wherein the luminance of the planar light source unit is used in the pulse width modulation control of the light emitting diodes constituting the planar light source unit by increasing or decreasing The load ratio is increased or decreased. 17. The driving method according to claim 16, wherein a control signal corresponding to an input signal having a value equal to (1+k ₀ )x _max is provided to the pixel when available, where k ₀ is at 0.06≤ The duty ratio D ₀ of pixel luminance in the case of a coefficient in the range of k ₀ ≤ 0.3 is represented by D ₀ =α ₀ ·D _max , where α ₀ is a coefficient in the range of 0.95 ≤ α ₀ ≤1.0, and D _max represents the maximum duty ratio. 18. The driving method according to claim 16, characterized in that a control signal corresponding to an input signal having a value equal to k ₁ x _max is provided to the pixel, wherein k ₁ is in the range 0.94≤k ₀ ≤0.99 The load ratio D ₁ of pixel luminance in the case of a coefficient in the range of is expressed by D ₁ =α ₁ ·D _max , where α ₁ is a coefficient in the range of 0.3≤α ₀ ≤0.8, and D _max represents the maximum load ratio. 19. The driving method according to claim 16, characterized in that it is possible to obtain a duty ratio _D2 of pixel luminance in a case where a control signal corresponding to an input signal having a value equal to _k2 · _xmax is supplied to the pixel It is expressed by D ₂ =α ₂ ·D _max , where α ₂ is a coefficient in the range of 0.01≦α0≦0.2, and D _max represents the maximum duty ratio.

Images