US20160019855A1

US20160019855A1 - Touch display device and driving method thereof

Info

Publication number: US20160019855A1
Application number: US14/801,216
Authority: US
Inventors: Chi Kang Liu
Original assignee: MStar Semiconductor Inc Taiwan
Current assignee: MStar Semiconductor Inc Taiwan
Priority date: 2014-07-21
Filing date: 2015-07-16
Publication date: 2016-01-21
Also published as: CN105278730A; TW201604753A; US20160018927A1; TWI554916B; US10372273B2; CN105278730B; TWI529597B; CN105278779A; TWI560593B; TW201604734A; US10606420B2; TW201604738A; CN105302392A; US20160019854A1

Abstract

A touch display device includes a display panel and a transparent conductive pattern layer. The display panel has a display side and a back side opposite to each other, and includes a plurality of data lines extending along a first direction. The data lines transmit a plurality of touch signals and display signals. The transparent conductive pattern layer is disposed on the display side, and includes a plurality of sensing electrodes extending along a second direction. The sensing electrodes intersect and are electrically insulated from the data lines to form a touch sensing element.

Description

This application claims the benefit of U.S. Provisional Application Ser. No. 62/027,236, filed Jul. 21, 2014, the subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates in general to a touch display device and a driving method thereof, and more particularly, to a touch display device that utilizes data lines of a display panel and a transparent conductive pattern layer disposed on the display panel as a touch sensing element, and a driving method thereof.
2. Description of the Related Art
In the recent years, with extensive developments and applications of consumer electronic products, the number of application products employing touch display devices that integrate touch control and display functions also continues to expand. Some examples of these application products include mobile phones, GPS navigation systems, tablet computers, personal digital assistants (PDAs), and laptop computers. Recently, manufacturers are also dedicated in developing wearable devices having a touch function. A conventional touch display panel is formed by directly attaching a touch panel with a display panel. The overall thickness and weight of such panels are greater than those of one single display panel, resulting in a burden in user portability. Therefore, there is a need for a solution for reducing the thickness of a touch display device.

SUMMARY OF THE INVENTION

It is a primary object of the present invention to provide a touch display device for reducing the thickness of the touch display device.
To achieve the above object, the present invention provides a touch display device. The touch display device includes a display panel and a transparent conductive pattern layer. The display panel has a display side and a back side opposite to each other, and a plurality data lines. The data lines extending along a first direction, and transmit a plurality of touch signals and display signals. The transparent conductive pattern layer is disposed on the display side, and includes a plurality of sensing electrodes extending along a second direction. The sensing electrodes intersect and are insulated from the data lines to form a touch sensing element.
To achieve the above object, the present invention further provides a driving method of a touch display device. The touch display device includes a display panel, and a transparent conductive pattern layer disposed on a display side of the display panel. The display panel includes a plurality of data lines extending along a first direction. The transparent conductive pattern layer includes a plurality of sensing electrodes extending along a second direction. The sensing electrodes intersect and are insulated from the data lines. The driving method includes following steps. In a display period, a display signal is transmitted to at least one of the data lines. In a touch control period, a touch signal is transmitted to at least one of the data lines, and a sensing signal is received from at least one of the sensing electrodes corresponding to the data lines.
In the touch display device of the present invention, a touch sensing element is formed by the data lines and the transparent conductive pattern layer, and a touch electrode layer conventionally used for transmitting touch signals can be omitted, so as to effectively reduce the thickness and production costs of the touch display device. That is, the present invention realizes the touch function without needing to attach an additional touch electrode layer (e.g., an indium tin oxide (ITO) layer).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a section view of a touch display device according to a first embodiment of the present invention;

FIG. 2 is a top view of an array substrate according to the first embodiment of the present invention;

FIG. 3 is a top view of data lines and a transparent conductive pattern layer according to the first embodiment of the present invention;

FIG. 4 is a circuit diagram of a touch display device of the present invention;

FIG. 5 is a flowchart of a driving method of a touch display device of the present invention;

FIG. 6 is a timing diagram of a gate signal transmitted by a gate line, a touch signal and a display signal transmitted by a data line, and a sensing signal sensed by a sensing electrode of the present invention;

FIG. 7 is a top view of a sensing electrode according to a second embodiment of the present invention;

FIG. 8 is a section view of a touch display device according to a third embodiment of the present invention; and

FIG. 9 is a section view of a touch display device according to a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The above and other aspects of the invention will become better understood with regard to the following detailed description of the preferred but non-limiting preferred embodiments. The following description is made with reference to the accompanying drawings.
FIG. 1 shows a section view of a touch display device according to a first embodiment of the present invention. As shown in FIG. 1, a touch display device 100 includes a display panel 102 and a transparent conductive pattern layer 104. The display panel 102 has a display side 102 a and a back side 102 b opposite each other. The transparent conductive pattern layer 104 is disposed on the display side 102 a. In the embodiment, the display panel 102 is a liquid crystal panel (LCD), e.g., a twisted nematic (TN) LCD, a vertically aligned LCD, or an organic light emitting diode (OLED) display panel. In the embodiment, the display panel 102 includes an array substrate 106, a color filter substrate 108 and a liquid crystal layer 110. The array substrate 106 and the color filter substrate 108 are disposed opposite to each other, and the liquid crystal layer 110 is disposed between the array substrate 106 and the color filter substrate 108. In the embodiment, the array substrate 106 is located on the color filter substrate 108, and so an outer surface of the array substrate 106 is the display side 102 a and an outer surface of the color filter substrate 108 is the back side 102 b.
More specifically, refer to FIG. 2 and FIG. 3 as well as FIG. 1. FIG. 2 shows a top view of an array substrate according to the first embodiment of the present invention. FIG. 3 shows a top view of data lines and a transparent conductive pattern layer according to the first embodiment of the present invention. As shown from FIG. 1 to FIG. 3, the array substrate 106 includes a first substrate 112 and a plurality of data lines 114. The first substrate 112 has a first inner surface 112 and the display side 102 a opposite to each other. The data lines 114 are disposed between the first inner surface 112 a of the first substrate 112 and the liquid crystal layer 110, and extend along a first direction 116. The transparent conductive pattern layer 104 includes a plurality of sensing electrodes 118 extending along a second direction 120 different from the first direction 116. As such, the sensing electrodes 118 may intersect the data lines 114, and are electrically insulated from the data lines 114 via the first substrate 112. In the embodiment, for example, the transparent conductive layer 104 may include indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide, or aluminum tin oxide. It should be noted that, the sensing electrodes 118 and the data lines 114 may couple to each other so as to generate sensing capacitors C between the sensing electrodes 118 and the data lines 114, such that the sensing electrodes 118 and the data lines 114 may form a touch sensing element. In the embodiment, the data lines 114 may be used to transmit touch signals and display signals. Thus, not only that the display panel 102 is allowed to display an image, but also the touch sensing element may detect a position of touch object, e.g., a finger or a stylus, touching or approaching the touch display device 100 through sensing signals from the sensing electrodes 118.
The array substrate 106 may further include a plurality of gate lines 122, a plurality of thin-film transistors (TFTs) 124 and a plurality of pixel electrodes 126 disposed between the liquid crystal layer 110 and the first inner surface 112 a. The gate lines 122 extend along the second direction 120, and intersect the data lines 114. Each of the TFTs 124 is disposed in a region surrounded by two adjacent gate lines 118 and two adjacent data lines 114, and includes a gate 128, a gate insulation layer 130, a semiconductor island 132, a source 134 and a drain 136. Each gate 128 is connected to one corresponding gate line 122, i.e., the gates 128 of the TFTs 124 arranged at the same row are electrically connected to the same gate line 122. In the embodiment, the gates 128 and the gate lines 122 are formed by a first metal pattern layer M1. The gate insulation layer 130 covers the first metal pattern layer M1 and the first inner surface 112 a. The semiconductor island 132 is disposed on the gate insulation layer 130 corresponding to gates 128, and may be formed by a non-silicon, doped non-silicon, polysilicon or metal oxide semiconductor, for example. The sources 134 and the drains 136 are disposed on the semiconductor island 132 and the gate insulation layer 130, and are disposed correspondingly at two sides of the gates 128. Each source 134 is electrically connected to one corresponding data line 114, i.e., the drains 134 of the TFTs 124 arranged at the same column are electrically connected to the same data line 114. For example, the sources 134, the drains 136 and the data lines 114 are formed by a second metal pattern layer M2. The type of TFTs in the present invention is not limited to the above example, and may be other types, e.g., top-gate TFTs. In the embodiment, the pixel electrodes 126 are disposed on the drains 136 and the gate insulation layer 130, and are electrically connected to the drains 136. Each of the pixel electrodes 126 extends to overlap with the corresponding gate line 122 to form a storage capacitor Cst. The storage capacitor in the present invention is not limited to be formed by a pixel electrode and a gate line. In another embodiment, the array substrate may further include common lines, and the storage capacitors are formed by the pixel electrodes that mutually couple with the common lines.
The color filter substrate 108 may include a second substrate 138, a black matrix layer 140, a color filter layer 142 and a common electrode layer 144. The second substrate 138 has a second inner surface 138 a and a back side 102 b opposite to each other. The liquid crystal layer 110 is disposed between the first inner surface 112 a of the first substrate 112 and the second inner surface 138 of the liquid crystal layer 110. The color filter layer 142 is disposed between the liquid crystal layer 110 and the second inner surface 138 a, and is disposed correspondingly to the pixel electrodes 126. The common electrode layer 144 is disposed between the black matrix layer 140 and the liquid crystal layer 110 as well as between the color filter layer 142 and the liquid crystal layer 110. The common electrode layer 144, the pixel electrodes 126 and the liquid crystal layer 110 form a liquid crystal capacitor Clc. For example, to flatten the common electrode layer 144, a flat layer 146 may be further disposed between the color filter layer 142 and the black matrix layer 140. Thus, the common electrode layer 144 may provide the liquid crystal layer 110 with an even electric field. In the embodiment, for example, the first substrate 112 and the second substrate 138 may be formed by transparent substrates, e.g., glass, acrylic, quartz, sapphire or plastic. In another embodiment, the array substrate and the color filter substrate may further include an alignment film for determining alignment directions of liquid crystal particles.
In the embodiment, as the display panel 102 is a liquid crystal panel, the display touch device 100 may further include a backlight module 148, for example. The backlight module 148 is disposed facing the back side 102 b, and provides light for image display. The touch display device 100 may further include a first polarization film 150 and a second polarization film 152 respectively disposed on the display side 102 a and the back side 102 b, and the transparent conductive pattern layer 104 is disposed between the first polarization film 150 and the display panel 102. The polarization direction of the first polarization film 150 and the polarization direction of the second polarization film 152 may be determined according to the alignment directions of the alignment film and operation principles of the display panel 102. For example, when the alignment directions of the alignment film are perpendicular to each other and the display panel 102 is a normally black type, the polarization direction of the first polarization film 150 is perpendicular to the polarization direction of the second polarization film 152. It should be noted that the present invention is not limited to the above example.
FIG. 4 shows a circuit diagram of a touch display device of the present invention. As shown in FIG. 4, in the embodiment, the data line 114 and the sensing electrodes 118 may be electrically connected to a control element 154. The control element 154 provides touch signals and display signals to the data lines 114 and receive sensing signals from the sensing electrodes 118.
A driving method of a touch display device according to an embodiment of the present invention, and how image display and touch sensing functions are simultaneously provided are described in detail below. FIG. 5 shows a flowchart of a driving method of a touch display device of the present invention. As shown in FIG. 5, the driving method of the touch display device 100 includes following steps.
In step S10, in a display period DT, a display signal F is transmitted to at least one of the data lines 114, and a gate signal is transmitted to at least one of the gate lines.
In step S12, in a touch control period TT, a touch signal T is transmitted to at least one of the data lines 114, and a sensing signal Rx is received from at least one of the sensing electrodes 118 corresponding to the at least one data line 114.
FIG. 6 shows a timing diagram of a gate signal transmitted by a gate line, a touch signal and a display signal transmitted by a data line, and a sensing signal received from a sensing electrode. As shown in FIG. 6, in the embodiment, a driving period of the touch display device 100 may include a display period DT and a touch control period TT, which do not overlap with each other.
Referring to FIG. 4 to FIG. 6, in step S10, the display signal F may be transmitted to the data line 114 via the control element 154. Further, gate signals G1 to Gn corresponding to the display signal F transmitted by the data line 114 may be transmitted to the corresponding gate lines 112 via a gate driving circuit or another control element to turn on the corresponding TFT 124, so as to further provide the pixel electrodes 126 with a desired pixel voltage. Further, a common voltage is applied to the common electrode layer 144. At this point, the touch display device 100 is allowed to display an image.
In step S12, since the touch control period TT and the display period DT do not overlap, the control element 154 may transmit the touch signal T different from the display signal F to the data line 114, and receive the sensing signals Rx from the sensing electrodes 118 corresponding to the data line 114 at the same time. As such, the control element 154 may detect the position of an object touching or approaching the touch display device 100. It should be noted that, in the touch control period TT, the gate lines 122 do not transmit gate signals to avoid from turning on the TFTs 124, so as to further prevent the touch signal T from affecting the voltage difference between the pixel voltage and the common voltage. Thus, the image displayed by the touch display device 100 is free from interference of touch sensing.
In the embodiment, the display period DT is the time that the display panel displays one frame. Therefore, the touch display device 100 may transmit the touch signal T to the data line and receive the sensing signal Rx between display periods DT of displaying different frames. In another embodiment, the display period may be divided into two periods, which respectively correspond to different gate signals of the same frame. The touch control period may be located between the periods of any two adjacent display signals to prevent the displayed image from interference of the touch signal.
It should be noted that, in the touch display device of the present invention, as the display signal F and the touch signal T may be integrated into the touch signal and the display signals D1 to Dn, the data lines not only serve as conducting lines that the display panel uses for transmitting the pixel voltage, but also form a touch sensing element with the transparent conductive pattern layer. As such, while omitting the touch electrode layer for transmitting touch signals, the touch display device of the present invention is capable of realizing touch sensing to further effectively reduce the thickness and costs of the touch display device.
The touch display device of the present invention is not limited to the above embodiment. Other embodiments are further disclosed below. For the sake of simplicity and to emphasize differences between the embodiments and variations, the same elements are represented by the same denotations, and associated description is omitted.
FIG. 7 shows a top view of a sensing electrode according to a second embodiment of the present invention. Referring to FIG. 7, compared to the first embodiment, a sensing electrode 202 of the embodiment includes a plurality of strip-like electrodes 204 and a comb pattern. More specifically, each sensing electrode 202 includes a plurality of strip-like electrodes 204 and a connecting electrode 206. The strip-like electrodes 204 extend along the second direction 120, and the connecting electrode 206 connects end points of the strip-like electrodes 204.
FIG. 8 shows a section view of a touch display device according to a third embodiment of the present invention. As shown in FIG. 8, compared to the first embodiment, a display panel 302 of a touch display device 300 of the embodiment may be an in-plane switching (IPS) LCD panel, and outer surfaces of an array substrate 304 and a color filter substrate 306 are respectively the back side 102 b and the display side 102 a. Thus, the transparent conductive pattern layer 104 is disposed on the outer surface of the color filter substrate 306.
More specifically, in the array substrate 304 of the embodiment, the first substrate 112 has the back side 102 b, and the second substrate 138 has the display side 102 a. The transparent conductive pattern layer 104 is disposed between the display side 102 a and the first polarization film 150. Further, TFTs 308 of the embodiments are top-gate TFTs, and so gates 310 are disposed between sources 312 and the liquid crystal layer 110 and between drains 314 and the liquid crystal layer 110. A pixel electrode pattern 316 and the common electrode pattern 318 of the array substrate 304 are disposed between the liquid crystal layer 110 and the first inner surface 112 a, and are patterned electrodes. Thus, the voltage difference between the pixel electrode pattern 316 and the common electrode pattern 318 may provide the liquid crystal layer 110 with a horizontal electric field to achieve a wide viewing angle. For example, the array substrate 304 may further including a light shielding layer 320 and an insulation layer 322. The light shielding layer 320 is disposed on the first inner surface 112 a, and the insulation layer 322 covers the light shielding layer 320 and the first inner surface 112 a. The light shielding layer 320 may be formed by the first metal pattern layer M1. A semiconductor island 324 is disposed on the insulation layer 322, and the light shielding layer 320 is disposed between the semiconductor island 324 and the first inner surface 112 a, such that the light shielding layer 320 may shield against light generated by the backlight module 148 disposed at the back side 102 b to prevent the light from illuminating the part of the semiconductor island 324 that serves as a passage. The sources 312 and the drains 314 formed by the second metal pattern layer M2 are disposed on the semiconductor island 324. A gate insulation layer 326 covers the second metal pattern layer M2 and the semiconductor island 324. The gates 310 are disposed on the gate insulation layer 326, and are disposed correspondingly to the semiconductor island 324. The gates 310 may be formed by a third metal pattern layer M3. The array substrate 304 further includes a dielectric layer 328, the pixel electrode pattern 316 and the common electrode pattern 318. The dielectric layer 328 covers the gates 310 and the gate insulation layer 326, and the gate insulation layer 326 and the dielectric layer 328 have a plurality of through holes TH that reveal the drains 314. Thus, the pixel electrode pattern 316 may electrically connect to the drains 314 via the through holes TH. The pixel electrode pattern 316 and the common electrode pattern 318 are disposed on the dielectric layer 328. In the embodiment, the pixel electrode pattern 316 and the common electrode pattern 318 may be formed by the same transparent conductive pattern layer, for example. Further, as the display panel 302 of the embodiment is an IPS LCD panel, the color filter substrate 306 need not be provided with a common electrode layer. Thus, the sensing capacitors C formed by the transparent conductive pattern layer 104 and the data lines 114 do not become inoperable when shielded by the common electrode layer. In another embodiment, the TFTs may be bottom-gate TFTs, and the array substrate may accordingly exclude the shielding layer and the insulation layer.
FIG. 9 shows a section view of a touch display device according to a fourth embodiment of the present invention. As shown in FIG. 9, the display panel 302 of a touch display device 400 of the embodiment is also an IPS LCD panel. However, compared to the third embodiment, the outer surface of the array substrate 304 of the embodiment is a display side 402 a, and the outer surface of the color filter substrate 306 is a back side 402 b. Thus, the transparent conductive pattern layer 104 is disposed on the outer surface of the array substrate 304, and the backlight module 148 is disposed facing the outer surface of the color filter substrate 306. The array substrate 304 and the color filter substrate 306 of the embodiment are identical to those of the third embodiment, and associated description shall be omitted herein.
In conclusion, in the touch display device of the present invention, the data lines may be used to transmit touch signals containing touch signals and image data signals as well as display signals. Thus, the data lines can not only serve as conducting wires that the display panel uses for transmitting the pixel voltage, but also form a touch sensing element with the transparent conductive pattern layer. Therefore, the touch display device of the present invention eliminates a touch electrode layer for transmitting touch signals to effectively reduce the thickness and costs of the touch display device.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.

Claims

What is claimed is:

1. A touch display device, comprising:

a display panel, having a display side and back side opposite to each other, comprising a plurality of data lines extending along a first direction, the data lines configured to transmit a plurality of touch signals and display signals; and

a transparent conductive pattern layer, disposed on the display side, comprising a plurality of sensing electrodes extending along a second direction, the sensing electrodes intersecting and being electrically insulated from the data lines to form a touch sensing element.

2. The touch display device according to claim 1, wherein the display panel further comprises:

a first substrate, having a first inner side and the display side opposite to each other;

a second substrate, disposed opposite the first substrate, having a second inner surface and the back side opposite to each other; and

a liquid crystal layer, disposed between the first inner surface of the first substrate and the second inner surface of the second substrate;

wherein, the data lines are disposed between the first inner surface and the liquid crystal layer.

3. The touch display device according to claim 2, wherein the display panel further comprises:

a plurality of gate lines, disposed between the liquid crystal layer and the first inner surface, interesting and being insulated from the data lines;

a plurality of thin-film transistors (TFTs), disposed between the liquid crystal layer and the first inner surface, each of the TFTs comprising a gate, a source and a drain, each of the gates electrically connecting to one of the corresponding gate lines, each of the sources electrically connecting to one of the corresponding data lines;

a plurality of pixel electrodes, disposed between the liquid crystal layer and the first inner surface, electrically connecting to the drains;

a black matrix layer, disposed between the liquid crystal layer and the second inner surface;

a color filter layer, disposed between the liquid crystal layer and the second inner surface; and

a common electrode layer, disposed between the liquid crystal layer and the color filter layer.

4. The touch display device according to claim 2, wherein the display panel further comprises:

a plurality of gate lines, disposed between the liquid crystal layer and the first inner surface, intersecting and being insulated from the data lines;

a plurality TFTs, disposed between the liquid crystal layer and the first inner surface, each of the TFTs comprising a gate, a source and a drain, each of the gates electrically connecting to one of the corresponding gate lines, each of the sources electrically connecting to one of the corresponding data lines;

a plurality of pixel electrode patterns, disposed between the liquid crystal layer and the first inner surface, electrically connecting to the drains;

a common electrode pattern, disposed between the liquid crystal layer and the first inner surface;

a black matrix layer, disposed between the liquid crystal layer and the second inner surface; and

a color filter layer, disposed between the liquid crystal layer and the second inner surface.

5. The touch display device according to claim 1, wherein the display panel further comprises:

a first substrate, having a first inner side and the back side opposite to each other;

a second substrate, disposed opposite to the first substrate, having a second inner surface and the display side; and

6. The touch display device according to claim 5, wherein the display panel further comprises:

a plurality of TFTs, disposed between the liquid crystal layer and the first inner surface, each of the TFTs comprising a gate, a semiconductor island, a source and a drain, each of the gates electrically connecting to one of the corresponding gate lines, each of the sources electrically connecting to one of the corresponding data lines;

7. The touch display device according to claim 6, wherein the gates are disposed between the sources and the liquid crystal layer and between the drains and the liquid crystal layer, and the display panel further comprises a light shielding layer disposed between the semiconductor islands and the first inner surface.

8. The touch display device according to claim 1, wherein each of the sensing electrodes has a comb-like pattern and comprises a plurality of strip-like electrodes and a connecting electrode, the strip-like electrodes extend along the second direction, and the connecting electrode connects end points of the strip-like electrodes.

9. The touch display device according to claim 1, wherein the data lines and the sensing electrodes electrically connect to a control element, and the control element provides the touch signals and the display signals.

10. The touch display device according to claim 1, further comprising a backlight module disposed facing the back side.

11. The touch display device according to claim 1, further comprising a first polarization film and a second polarization film respectively disposed on the display side and the back side, wherein the transparent conductive pattern layer is disposed between the first polarization film and the display panel.

12. A driving method of a touch display device, the touch display device comprising a display panel and a transparent conductive pattern layer disposed on a display side of the display panel, the display panel comprising a plurality of data lines extending along a first direction, the transparent conductive pattern layer comprising a plurality of sensing electrodes extending along a second direction, the sensing electrodes intersecting and being electrically insulated from the data lines; the driving method comprising:

in a display period, transmitting a display signal to at least one of the data lines; and

in a touch control period, transmitting a touch signal to at least one of the data lines, and receiving a sensing signal from at least one of the sensing electrodes corresponding to the data lines.

13. The driving method according to claim 12, wherein the display panel further comprises a plurality of gate lines; and the gate lines intersect and are electrically insulated from the data lines, and transmit a gate signal to at least one of the gate lines in the display period.

14. The driving method according to claim 12, wherein display period does not overlap with the touch control period.