WO2018161264A1

WO2018161264A1 - Touch-control chip, capacitive touch screen, capacitive active pen and bidirectional communication method for capacitive touch screen and capacitive active pen

Info

Publication number: WO2018161264A1
Application number: PCT/CN2017/075906
Authority: WO
Inventors: 陈小祥
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2017-03-07
Filing date: 2017-03-07
Publication date: 2018-09-13
Also published as: CN109074200A; CN109074200B

Abstract

A touch-control chip (260) connected to a capacitive touch screen (20), wherein the capacitive touch screen (20) comprises a plurality of driving electrode channels (Y), a plurality of sensing electrode channels (X) and a display module (220); and the touch-control chip (260) comprises a control unit (261), a driving circuit (262), a sensing circuit (263) and a multiplexing unit (264) which are electrically connected to one another. After the control unit (261) drives the sensing circuit (263) to detect an interference signal from the display module (220) and carries out spectral analysis on the interference signal so as to select the minimum intensity value of the interference signal or a frequency point, the difference between same and the minimum intensity value being less than a set threshold value, as a working frequency point, information about the working frequency point is sent to a capacitive active pen (10) applied to the capacitive touch screen (20), and the capacitive active pen (10) selects a driving frequency according to the working frequency point.

Description

Two-way communication method of touch chip, capacitive touch screen, capacitive active pen, capacitive touch screen and capacitive active pen

Technical field

The invention relates to a touch chip applied to a capacitive touch screen, in particular to a touch chip capable of two-way communication between a capacitive touch screen and a capacitive active pen and allowing the capacitive active pen to dynamically switch the output signal frequency.

Background technique

With the popularity of capacitive touch screens, the use of capacitive active pens and capacitive touch screens has become more widespread. As shown in FIG. 1 , a typical capacitive touch screen 2 with a display function has a touch screen sensing layer 21 , a display module 22 , a glass cover 23 , and a touch screen sensing layer 21 and a display module 22 respectively. And an optically clear adhesive layer (OCA) 24 and 25 interposed between the touch screen sensing layer 21 and the cover glass 23. The touch screen sensing layer 21 includes a driving electrode channel and a sensing electrode channel, and the display module 22 is, for example, a liquid crystal display (LCD) module.

When a capacitive active pen 1 is in contact with a capacitive touch screen 2 of a matching application, a coupling capacitor is formed between the tip electrode of the capacitive active pen 1 and each of the driving electrode channels or the sensing electrode channels of the touch panel sensing layer 21. The smaller the distance between the nib electrode and the driving electrode channel or the sensing electrode channel, the larger the coupling capacitance value. In addition, when the tip electrode of the capacitive active pen 1 outputs a signal, these signals are transmitted to the driving electrode channel and the sensing electrode channel through the coupling capacitor, and the detected signal intensity on these channels becomes smaller as the distance from the pen tip is smaller. Large, the two-dimensional coordinates of the position of the nib of the capacitive active pen 1 can be calculated by separately calculating the signal strengths of the coupling signals on the driving electrode channel and the sensing electrode channel.

In a common case, when the driving electrode channel and the sensing electrode channel in the touch screen sensing layer 21 receive the output signal of the pen tip electrode of the capacitive active pen 1, the driving chip of the display module 22 under the touch screen sensing layer 21 is also simultaneously output. Drive signal to the display unit to refresh the display screen, this drive The dynamic signal is also coupled to the touch screen sensing layer 21 such that the signal-to-noise ratio (SNR) of the output signal of the capacitive active pen 1 detected by the control chip connected to the touch screen sensing layer 21 is deteriorated. .

Such an object from the capacitive touch screen 2 and the capacitive active pen 1 , such as the display module 22 , and the coupling signal between the touch screen sensing layer 21 form an interference signal for the capacitive active pen 1 . The distance between the driving signal layer of the display module 22 or the display module 22 and the sensing electrode channel is smaller than the distance between the pen tip of the capacitive active pen 1 and the sensing electrode channel, so that the interference signal has a large When the signal intensity is generated, the coordinates of the capacitive active pen 1 may be shaken, and a point may affect the normal operation of the user.

Summary of the invention

In order to solve the foregoing problems, the present invention discloses a two-way communication method of a touch chip, a capacitive touch screen, a capacitive active pen, a capacitive touch screen and a capacitive active pen, which is intended to remove a capacitive touch screen and a capacitive active pen. The interference signal of the object affects the normal operation of the capacitive active pen on the capacitive touch screen, and improves the pen writing effect of the user.

In one embodiment, the present invention discloses a touch chip connected to a capacitive touch screen. The capacitive touch screen includes a plurality of driving electrode channels and a plurality of sensing electrode channels, and the touch chips include electrical connections with each other. A first control unit, a driving circuit, a sensing circuit and a multiplexing unit. The first control unit drives the multiplexing unit to electrically connect the sensing electrode channel and the sensing circuit, the driving circuit does not output any signal to the driving electrode channel, and the first control unit drives The sensing circuit detects a first signal from the object except the capacitive touch screen and is received by the sensing electrode channel, and performs spectrum analysis on the first signal to select a minimum intensity value of the first signal Or a frequency point that differs from the minimum intensity value by less than a set threshold as a working frequency point.

In one embodiment, the first control unit drives the multiplexing unit to electrically connect the driving circuit with the driving power and the channel.

In one embodiment, the object except the capacitive touch screen further includes a display module, the display module is disposed at a distance from the sensing electrode channel, and the first signal further includes the display module coupling a signal to the sensing electrode channel.

In one embodiment, the touch chip further includes a minimum interference frequency selection unit electrically connected to the first control unit, and the first control unit drives the minimum interference frequency selection unit to After the first signal is subjected to spectrum analysis, the working frequency point is selected.

In one embodiment, the capacitive touch screen is further touched by a capacitive active pen, and the first control unit drives the multiplexing unit to be electrically connected to the sensing electrode channel and the driving circuit. And driving the driving circuit to send a second signal loaded with the working frequency point information to the driving electrode channel and the sensing electrode channel and coupled to the capacitive active pen.

Optionally, the transmitting of at least two of the second signals includes the transmission of one data bit.

Optionally, the touch chip further includes a modulation unit electrically connected to the first control unit, the first control unit driving the modulation unit to load the working frequency point information to In the second signal.

Optionally, the first control unit detects a third signal sent by the capacitive active pen, and the detected current frequency of the third signal is different from the frequency of the working frequency point but Before the frequency of the working frequency point has not been switched, the frequency of the third signal in the current period and the next period is alternately detected.

In one embodiment, the capacitive active pen includes a control chip, and the pen control chip includes a second control unit electrically connected to each other, a tip electrode and a frequency point switching unit, and the second control The unit sequentially drives the nib electrode to send a third signal to the capacitive touch screen, driving the nib electrode to detect and receive the second signal, and decomposing the working frequency information from the second signal, And driving the frequency point switching unit to switch the frequency point of the third signal sent in the next period from the current periodic frequency point to the working frequency point.

In an embodiment, the pen control chip further includes a demodulation unit electrically connected to the second control unit, and the second control unit drives the demodulation unit to transmit the working frequency information from the Decomposed in the second signal.

In an embodiment, the pen control chip further includes a check unit electrically connected to the second control unit, the second control unit driving the check unit to verify the decomposition from the second signal The correctness of the working frequency information.

In an embodiment, the first control unit drives the multiplexing unit to change both the driving electrode channel and the sensing electrode channel when the third signal is sent to the capacitive touch screen. Electrically connecting to the sensing circuit and driving the sensing circuit to detect the third signal, comparing The current periodic frequency point of the third signal and the working frequency point.

Optionally, the first control unit drives the sensing circuit to detect that the detection frequency value of the third signal is equal to a transmission frequency value that the second control unit drives the nib electrode to transmit the third signal. Optionally, the time required for the second control unit to drive the nib electrode to detect the second signal once is equal to the time required for the first control unit to drive the driving circuit to send the second signal once.

Optionally, the second control unit drives the nib electrode to detect the time required for each of the second signals to be 100 us.

In one embodiment, the present invention discloses a capacitive touch screen that is coupled to the touch chip of one of the previous embodiments.

In one embodiment, the present invention discloses a capacitive active pen that communicates bidirectionally with a capacitive touch screen to which the touch chip of one of the preceding embodiments is coupled.

In another embodiment, the present invention discloses a two-way communication method between a capacitive touch screen and a capacitive active pen. The method includes the following steps in each communication cycle: the capacitive touch screen detects the capacitive touch screen and the capacitor a first signal of the object except the active pen, and performing spectrum analysis on the first signal, and selecting a minimum intensity value of the first signal or a frequency point different from the minimum intensity value by less than a set threshold As the working frequency point, when the capacitive active pen touches the capacitive touch screen, the capacitive touch screen loads the working frequency point information in a second signal; and the capacitive active pen touches the In the capacitive touch screen, the capacitive touch screen detects a third signal sent by the capacitive active pen; when the capacitive active pen touches the capacitive touch screen, the capacitive touch screen determines the When the current periodic frequency of the third signal is different from the working frequency, the capacitive touch screen sends the second signal to the capacitive active pen; When the capacitive active pen touches the capacitive touch screen, the capacitive active pen detects and receives the second signal, and decomposes the working frequency point information from the second signal; and at the capacitor When the active pen touches the capacitive touch screen, the capacitive active pen determines that the current periodic frequency of the third signal is different from the working frequency, and the capacitive active pen transmits the next cycle. The frequency of the third signal is switched from the current periodic frequency point to the working frequency point.

In an embodiment, the method for bidirectional communication between the capacitive touch screen and the capacitive active pen further includes the following steps: when the capacitive active pen touches the capacitive touch screen, the capacitive touch screen determines the third signal The capacitive touch screen continues when the current periodic frequency is the same as the working frequency Detecting a current periodic frequency of the third signal.

In an embodiment, the method for bidirectional communication between the capacitive touch screen and the capacitive active pen further includes the following steps: when the capacitive active pen touches the capacitive touch screen, the capacitive touch screen determines the third signal When the frequency point has not been switched from the current periodic frequency point to the working frequency point, the capacitive touch screen detects the current periodic frequency point of the third signal in a current period and detects the third time in a next period The new frequency of the signal.

In an embodiment, the method for bidirectional communication between the capacitive touch screen and the capacitive active pen further includes the following steps: when the capacitive active pen touches the capacitive touch screen, the capacitive active pen is verified from the first The correctness of the working frequency point information decomposed by the two signals.

In the disclosure of the present invention, the touch sensor connected to the capacitive touch screen detects the interference of the capacitive touch screen and the capacitive active pen, including the interference signal generated by the display module, and performs spectrum analysis on the interference signal, and selects one. The minimum intensity value of the interference signal or the frequency point that differs from the minimum intensity value by less than a set threshold is used as an optimal working frequency point, and the optimal working frequency point is sent to the capacitive active pen through the touch chip. At the same time, the pen control chip connected by the capacitive active pen can receive the optimal working frequency point information, and select the driving frequency according to the optimal working frequency point, so as to avoid the interference signal generated by the display module, so that The use of the capacitive active pen will not be affected by the interference signal of high intensity, and the jitter or the point will be shaken, and the touch glitch which may be caused by the interference signal with less intensity is avoided, and the normal operation of the capacitive active pen is ensured by the user. In addition, the use of the threshold setting avoids frequent switching between several frequency points where the interference signal strengths differ very little.

DRAWINGS

FIG. 1 is a schematic view showing a known capacitive touch screen structure with display function and a matched capacitive active pen.

2 is a schematic diagram showing two-way communication between a capacitive touch screen and a matched capacitive active pen according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing the signal output and input of the touch chip in the finger detection mode of the capacitive touch screen according to an embodiment of the invention.

4 is a schematic diagram showing signal input of a touch chip in a pen signal detection mode of a capacitive touch screen according to an embodiment of the invention.

FIG. 5 is a schematic diagram showing signal input of a touch chip in a pen signal detection mode of a capacitive touch screen according to an embodiment of the invention.

FIG. 6 is a block diagram showing the connection relationship between the touch chip and the pen control chip according to an embodiment of the present invention.

FIG. 7 is a schematic diagram showing signal detection timings of a capacitive touch screen and a capacitive active pen in a two-way communication according to an embodiment of the present invention.

FIG. 8 is a flow chart showing the signal processing process of the touch screen end in the two-way communication method of the capacitive touch screen and the capacitive active pen according to an embodiment of the invention.

FIG. 9 is a flow chart showing the signal processing process of the pen end in the two-way communication method of the capacitive touch screen and the capacitive active pen according to an embodiment of the present invention.

The implementation, functional features, and advantages of the present invention will be further described in conjunction with the accompanying drawings.

detailed description

The invention discloses a two-way communication method of a touch chip, a capacitive touch screen, a capacitive active pen, a capacitive touch screen and a capacitive active pen to avoid signal interference of the display unit. The basic fabrication principles and methods of the capacitive touch screen and the capacitive active pen are known to those of ordinary skill in the art, and therefore, the description below will not be fully described. It is understood that the specific embodiments described below are merely illustrative of the invention and are not intended to limit the invention. The related description of the chip involved in the present invention may be a single chip or a combination of multiple chips, or may refer to a collection of multiple circuits, and is not limited to a specific combination or package. The circuits, units, and modules included therein may be a distributed circuit structure or an integrated circuit in the form of a chip.

Referring to FIG. 2, the present invention discloses a capacitive touch screen. In one embodiment, the capacitive touch screen 20 can optionally have a display function, and thus has at least one touch screen sensing layer 210 and one display module 220. In one embodiment, the display module 220 is disposed under the touch screen sensing layer 210 to form an OUT-CELL structure, and optionally has a glass cover 230, optically transparent between the touch screen sensing layer 210 and the display module 220. An adhesive (OCA) layer 240 and an optically clear adhesive (OCA) layer 250 between the touch screen sensing layer 210 and the cover glass 230. The display module 220 is disposed at a distance from the touch screen sensing layer 210. In another embodiment, the touch screen sensing layer 210 can also be disposed inside the display module 220 to form an IN-CELL structure. At this time, the driving signal layer of the display module 220 is disposed at a distance from the touch screen sensing layer 210. Figure 3 As shown in FIG. 5, in the embodiment, the touch screen sensing layer 210 of the capacitive touch screen 20 includes a driving electrode channel Y and a sensing electrode channel X, and sends a signal to the driving electrode through an electrically connected touch screen controller 260. Channel Y, and receives signals from drive electrode channel Y and/or sense electrode channel X.

With continued reference to FIG. 2, in one embodiment, the capacitive touch screen 20 is in two-way communication with a capacitive active pen 10 (shown by

arrows

52 and 53 in the figure), and the capacitive touch screen 20 is not only capacitive. The active pen 10 receives a signal (hereinafter referred to as a third signal) 53 and also transmits a signal (hereinafter referred to as a second signal) 52 to the capacitive active pen 10. In this process, the driving electrode channel Y and the sensing electrode channel X of the touch screen sensing layer 210 are both used as the transmitting electrodes (or transmitting electrodes) of the second signal 52 except for the receiving electrodes of the third signal 53. The display module 220 belongs to an object other than the capacitive touch screen 20 and the capacitive active pen 10. Since the interference signal from the display module 220 is shielded by the electrodes in the touch screen sensing layer 210 when it is transmitted upward, the transmission of the second signal 52 is not affected. Therefore, the frequency of the second signal 52 transmitted by the capacitive touch screen 20 to the capacitive active pen 10 can be fixed.

Referring to FIGS. 3 to 5, in one embodiment, the touch chip 260 electrically connected to the driving electrode channel Y and the sensing electrode channel X has a control unit 261, a driving circuit 262, a sensing circuit 263, and a multiplex circuit electrically connected to each other. With the unit 264, the multiplexing unit 264 has a channel switching function, and the driving electrode channel Y and the sensing electrode channel X can be selectively connected to one of the driving circuit 262 and the sensing circuit 263 by the operation of the multiplexing unit 264. The signal from the driving circuit 262 can be sent to the driving electrode channel Y, and the sensing circuit 263 can also receive signals from the driving electrode channel Y and/or the sensing electrode channel X. Referring to FIG. 6, the touch chip 260 further has a minimum interference frequency selection unit 265 and a modulation unit 266 electrically connected to the control unit 261 for respectively causing interference to the components other than the capacitive touch screen 20 and the capacitive active pen 10. The signal, referred to as the first signal 51, performs spectral analysis to find the frequency of the minimum intensity value (ie, the frequency with the least interference), and selects the frequency of the minimum intensity value or differs from the minimum intensity value by less than a set threshold. The frequency point is used as the working frequency point, and the working frequency point information is loaded into the second signal 52. The spectrum analysis here specifically refers to sampling the first signal 51, and converting the sampled time domain signal into a frequency domain signal by a Fast Fourier Transform (FFT) module. Signal). On the other hand, the capacitive active pen 10 has a control chip 11 including a control unit 111, a frequency switching unit 112, a demodulation unit 113 and a verification unit 114 electrically connected to each other for controlling transmission to the capacitive type. The frequency of the third signal 53 of the touch screen 20, the frequency of the third signal 53 is dynamically switched, the operating frequency information of the received second signal 52 is decomposed, and the correctness of the information is verified. During the two-way communication between the capacitive touch screen 20 and the capacitive active pen 10, the touch chip 260 controls the second signal 52 in addition to the third signal 53 by the control unit 261. Another On the other hand, the pen control chip 11 controls the second signal 53 and switches the frequency in addition to the second signal 52 detected by the control unit 111.

Referring to FIG. 7, in an embodiment, the touch chip 260 of the capacitive touch screen 20 can alternately perform the following four modes in the detection timing in each cycle: (1) Finger touch detection mode: mutual capacitance detection mode detection can be adopted. The multi-finger touch is as shown in FIG. 3. In this mode, the control unit 261 drives the multiplexing unit 264 to perform channel switching, and the driving electrode channel Y is connected to the driving circuit 262 through the multiplexing unit 264, and the sensing electrode channel X The multiplexer unit 264 is connected to the sensing circuit 263, the finger 3 touches the capacitive touch screen 20, and the driving circuit 262 of the touch chip 260 outputs a driving signal to the driving electrode channel Y, and drives the electrode channel Y and the sensing electrode channel X. The coupling capacitance is coupled to the sensing electrode channel X and detected by the sensing circuit 263. The current touch position of the finger 3 can be calculated by the detected amount of change in the coupled signal on the sensing electrode channel X. (2) Noise detection mode: a detection mode of a signal generated by an object other than the capacitive touch screen 20 and the capacitive active pen 10, such a signal forming an operation of the capacitive active pen on the capacitive touch screen The interference includes signals from display module 220 and signals from the charger. In this mode, the control unit 261 drives the multiplexing unit 264 to perform channel switching, the driving electrode channel Y is connected to the driving circuit 262 through the multiplexing unit 264, and the sensing electrode channel X is connected to the sensing through the multiplexing unit 264. The circuit 263, the driving circuit 262 of the touch chip 260 does not output any signal to the driving electrode channel Y, that is, the driving circuit 262 does not output a driving signal to the driving electrode channel Y, and only the sensing circuit 263 detects that the sensing electrode channel X is received. signal of. At this time, a coupling signal from the display module 220 coupled to the sensing electrode channel X is detected. These detected signals will be spectrally analyzed by control unit 261 to find the frequency of the signal with the smallest intensity value (i.e., the frequency with the least interference). Here, the spectrum analysis, specifically, samples the signals generated by the capacitive touch screen 20 and the objects other than the capacitive active pen 10, and passes the sampled time domain signal through Fast Fourier Transform (Fast Fourier Transform). The FFT) module is converted to a frequency domain signal. This noise detecting mode can be performed regardless of whether there is a finger 3 or a touch of the capacitive active pen 10 on the capacitive touch screen 20. In the case where the finger 3 is touched on the capacitive touch panel 20, the noise detecting mode can be performed as long as the driving circuit 262 does not output a signal to the driving electrode channel Y or the driving circuit 262 is disconnected from the driving electrode channel Y. In the case where the capacitive touch pen 20 is touched by the capacitive touch pen 20, the noise detecting mode can be performed as long as the pen tip of the capacitive active pen 10 has not yet transmitted a signal. (3) Pen signal detection mode: that is, the third signal 53 emitted by the pen tip of the capacitive active pen 10 shown in FIG. 2 is detected, thereby obtaining the position of the pen point coordinate of the capacitive active pen 10. As shown in FIG. 4, in this mode, the control unit 261 drives the multiplexing unit 264 to perform channel switching, which is controlled by the control unit 261. The driving circuit 262 does not work, that is, does not output a driving signal, and the driving electrode channel Y and the sensing electrode channel X are connected to the sensing circuit 263 through the multiplexing unit 264, and the capacitive active pen 10 contacts the capacitive touch screen 20, The sensing circuit 263 sequentially detects the signal amount of the coupling signal coupled to the driving electrode channel Y and the sensing electrode channel X by the third signal 53 for synchronizing the detection frequency of the third signal 53 by the touch chip 260 and the third signal 53. The transmission frequency, the position of the tip coordinate of the capacitive active pen 10, and the code of the button or pressure of the pen end are received. (4) Frequency hopping coding mode: that is, outputting or transmitting the second signal 52 shown in FIG. 2 in the coding format, and notifying the frequency point of the minimum intensity value found by the capacitive active pen 10 in the noise detection mode (ie, the interference is minimal). Frequency point) or a frequency point that differs from the intensity minimum by less than a set threshold. As shown in FIG. 5, in this mode, the control unit 261 drives the multiplexing unit 264 to perform channel switching. Through the control of the control unit 261, the driving electrode channel Y and the sensing electrode channel X pass through the multiplexing unit 264. Connected to the driver circuit 262, the capacitive active pen 10 contacts the capacitive touch screen 20, and the second signal 52 is output or transmitted by the driver circuit 262 and coupled to the tip electrode of the capacitive active pen 10. By detecting and comparing the intensity of the second signal 52 with the threshold value, the pen control chip 11 of the capacitive active pen 10 can confirm whether or not the capacitive touch panel 20 outputs a valid signal at the current time.

Continuing to refer to FIG. 7, the timing of the pen signal detection mode and the frequency hopping coding mode can be represented by the T1 time period and the T2 time period, respectively. In the pen signal detection mode, that is, the T1 time period, the pen tip of the capacitive active pen 10 transmits the third signal 53, and the time required to transmit the third signal 53 once may be 100 us or 1 ms, and the touch chip of the capacitive touch screen 20 The 260 is coupled to the signal quantity of the coupled signal on the driving electrode channel Y and the sensing electrode channel X by the detected third signal 53 to complete the timing synchronization of the pen and the screen, the coordinate calculation of the pen tip position, and the transmission of the code of the button and the pressure of the pen end. (S indicates transmission and R indicates reception). In the frequency hopping coding mode, that is, the T2 time period, the tip electrode of the capacitive active pen 10 is controlled by the pen control chip 11, in particular, driven by the control unit 111, and is switched from the transmission signal mode to the reception signal mode to receive the capacitive touch screen 20. The transmitted second signal 52 (in the figure, S indicates transmission, and R indicates reception). The frequency of the second signal 52 transmitted by the capacitive touch screen 20 to the capacitive active pen 10 is fixed, but the output may or may not be output to transmit data each time the second signal 52 is transmitted. For example, the time required for the capacitive touch screen 20 to transmit the second signal 52 once is 100 us, and one data bit (Bit) can be transmitted every time the second signal 52 is transmitted two or more times. For example, if a data bit is sent within the time required to send the second signal 52 twice, if the data bit "1" needs to be transmitted, the signal may be output within the time required to send the first second signal, and the second signal is transmitted. The signal is not output for the time required for the second second signal; if the data bit "0" needs to be transmitted, the signal is not output for the time required to transmit the first and second second signals. In one embodiment, the pen control chip 11 of the capacitive active pen 10 detects the time required for each second signal 52 and can transmit the second time each time. The time required for the signal 52 is the same, for example 100us. By detecting the amount of data of the two adjacent second signals 52, the data bits transmitted by the capacitive touch screen 20 can be identified, for example, during the T2 time period, 6 can be detected. Second secondary signal 52. In the example of FIG. 7, in order to accommodate the synchronization error between the pen end and the screen end, only three data bits are transmitted in the time required to transmit the second signal 52 six times.

Referring to FIG. 6 and FIG. 7 , in an embodiment, when the touch chip 260 of the capacitive touch screen 20 performs the noise detection mode, the minimum interference frequency selection unit 265 electrically connected thereto is driven by the control unit 261 to capacitively. After the interference signal of the object other than the touch screen 20 and the capacitive active pen 10 or the first signal 51 is subjected to spectrum analysis, the frequency of the interference signal or the first signal 51 having the smallest intensity value (ie, the frequency with the least interference) is selected. Or a frequency point that differs from the minimum intensity value by less than a set threshold as the operating frequency point.

Referring to FIG. 6 and FIG. 7 , in an embodiment, when the touch chip 260 of the capacitive touch screen 20 performs the pen signal detection mode, the third signal 53 is detected by the control unit 261 . In the state where the interference is constant, the transmission frequency value of the third signal 53 should be the same as the detection frequency value of the touch-tip 260 detecting the tip coordinate of the capacitive active pen 10, otherwise the pen will be in an unusable state. For example, the frequency of the third signal 53 currently issued by the tip of the capacitive active pen 10 is 500 Khz, and the control unit 261 of the touch chip 260 is also detecting the signal of 500 Khz to calculate the position of the tip coordinate of the capacitive active pen 10, and the pen can be normal. If the frequency of the third signal 53 currently issued by the pen tip is 500Hhz, and the control unit 261 detects the position of the pen point coordinate by detecting the signal of 300Khz, the control unit 261 will not detect the valid signal, and always think that there is no pen currently. Signal, the pen is in an unusable state. Therefore, when the touch chip 260 of the capacitive touch screen 20 performs the pen signal detection mode, it is necessary to ensure that the frequency of the pen end and the screen end correspond.

Referring to FIG. 6 and FIG. 7 , in an embodiment, when the capacitive touch screen 20 performs the frequency hopping coding mode, the modulation unit 266 is driven by the control unit 261 to select the frequency of the selected minimum intensity value (ie, interference). The minimum frequency point) or the sequence number corresponding to the frequency point whose difference from the intensity minimum value is less than a set threshold value is modulated by the data bit representation or coded information and the check bit information (hereinafter collectively referred to as interference minimum frequency point information). It is loaded into the second signal 52 and detected by the pen control chip 11. For example, when there are 8 different frequency points selectable, the noise detection mode will analyze which of the 8 frequency points has the least interference, and select the frequency point corresponding to the frequency point with the least interference frequency. The information represented by or encoded by 3 data bits (Bit) and the information of the check bits are mixed into the second signal 52. Only when the capacitive touch screen 20 performs the frequency hopping coding mode, the pen control chip 11 drives the frequency point switching unit 112, the demodulation unit 113, and the verification unit 114 to operate through the control unit 111, and the received second signal 52 Performing demodulation to obtain data including information such as an encoding of the frequency point of the interference minimum frequency point or the intensity minimum value less than a set threshold value, and a parity bit, and further utilizing the information correctness of the parity check data and The third signal to be output in the next cycle 53 The frequency point is switched to a frequency point where the interference minimum frequency point or the intensity minimum value differs by less than a set threshold.

Referring to FIG. 6 and FIG. 8 , in an embodiment of the present invention, when the capacitive touch screen 20 and the capacitive active pen 10 are in two-way communication with the pen control chip 11 through the touch chip 260, the touch chip 260 executes the following step.

Step 711: Spectrum analysis. In the noise detection mode, the control unit 261 of the touch chip 260 performs spectrum analysis on the received interference signal or the first signal 51, and converts the time domain signal of the sampled first signal 51 into a frequency through a fast Fourier transform module. Domain signal.

Step 712: Select the frequency point with the least interference. In the noise detection mode, the minimum interference frequency selection unit 265 is driven by the control unit 261 to perform the spectrum analysis on the first signal 51 to select an interference signal or a frequency point with a minimum intensity value in the first signal 51 (ie, interference). The smallest frequency point) or a frequency point that differs from the minimum intensity value by less than a set threshold as the operating frequency point.

Step 713: Determine whether the current frequency point is a working frequency point. In the pen signal detection mode, the control unit 261 compares the frequency of use of the current cycle output or transmission of the third signal 53 by the capacitive active pen 10 with the operating frequency selected in step 712, and determines the current periodic frequency of the third signal 53. Whether the point is the selected working frequency point. Otherwise, it enters the frequency hopping state and performs step 714. If yes, go to step 715.

Step 714: Determine whether the pen end frequency hopping is completed. In the pen signal detection mode, the control unit 261 determines whether the frequency of the current period output third signal 53 has been switched to the operating frequency point, that is, the frequency hopping is completed. If the frequency hopping is completed, step 715 is performed. If the frequency hopping is not completed, step 716 is performed.

Step 715: Detect the current frequency point. In the pen signal detection mode, the control unit 261 continues to detect the current cycle frequency of the third cycle 53 of the current cycle of the capacitive active pen 10, and then performs step 717.

Step 716: alternately detecting new and old frequency points. In the pen signal detection mode, the control unit 261 detects the frequency point of the current output third signal 53 in the current cycle, and detects the new frequency point of the output third signal 53 in the next cycle until the frequency of the third signal 53 is detected. Has been switched to the working frequency point. In this case, it can be ensured that after entering the frequency hopping state, the control unit 261 can still detect that the pen control chip 11 has not successfully received the working frequency point notified by the touch chip 260 or the frequency of the third signal 53 has not been switched to the working frequency point. To the operation of the capacitive active pen 10, although the reporting rate will be reduced by half. When the frequency of the third signal 53 has been switched to the operating frequency point, step 717 is performed.

Step 717: Send a second signal. In the frequency hopping encoding mode, control unit 261 drives drive circuit 262 to transmit second signal 52. Regardless of whether the third signal 53 has been switched to the operating frequency point, the touch chip 260 sends a second signal 52 every cycle to notify the frequency point that the capacitive active pen 10 should currently use. The capacitive touch screen 20 is prevented from corresponding to the communication frequency of the capacitive active pen 10. In this way, even if the capacitive active pen 10 used is a new pen or a newly replaced battery, the capacitive active pen 10 can ensure that the second signal 52 is received.

Referring to FIG. 6 and FIG. 9 , in an embodiment of the present invention, when the capacitive touch screen 20 and the capacitive active pen 10 are in two-way communication with the pen control chip 11 through the touch chip 260, the capacitive active pen 10 therein The pen control chip 11 performs the following steps in each cycle.

Step 811: Send a third signal. When the touch chip 260 performs the pen signal detection mode, the pen control chip 11 first transmits the third signal 53 to the capacitive touch panel 20 with the currently used frequency value. After detecting the third signal 53, the touch chip 260 calculates the current position coordinates, the pen end button and the pressure value of the pen tip of the capacitive active pen 10 by the detected signal amount.

Step 812: Receive a second signal. After the control unit 111 of the pen control chip 11 drives the pen tip electrode to transmit the third signal 53, the transmission signal mode is switched to the reception signal mode, and the second signal 52 sent by the touch chip 260 is detected, and the second signal is received after the detection. 52. The touch chip 260 at this time should perform the frequency hopping coding mode.

Step 813: Verify the second signal. The pen control chip 11 further demodulates the received second signal 52 by using the demodulation unit 113 to acquire the information of the working frequency point carried in the second signal 52, and verify the demodulated information. To confirm that the information received is correct.

Step 814: Determine whether the verification of step 813 is passed. If the verification is in error, no processing is performed, and the pen control chip 11 continues to operate using the original frequency point and waits for the start of the new cycle, that is, step 817 is performed. If the verification is correct, that is, the received information is confirmed to be correct, step 815 is performed.

Step 815: Determine whether the current periodic frequency point is different from the new frequency point. The pen control chip 11 compares the operating frequency point included in the verified data with the frequency point used by the current period of the third signal 53, and determines whether the frequency point used in the current cycle is different from the new frequency point, that is, the working frequency point. If they are the same, no processing is performed, and the pen control chip 11 continues to work with the original frequency point and waits for the start of the new cycle, that is, step 817 is performed. If they are different, step 816 is performed.

Step 816: Switch to the new frequency point. The pen control chip 11 switches the frequency point used by the third period of the third signal 53 to the new frequency point, that is, the operating frequency point.

Step 817: The new cycle begins. Restarting a new cycle, the foregoing steps 811 to 816 are sequentially performed. When the third signal 53 is transmitted in a new cycle, the frequency value of the third signal 53 will switch to the operating frequency point.

Capacitive touch screen and capacitive active pen are detected by a touch chip connected to a capacitive touch screen The external object includes a display module, and the interference signal generated by the entire capacitive touch screen is subjected to spectrum analysis, and the frequency of the minimum intensity value of the interference signal is selected or less than one of the minimum intensity values. Set the frequency of the threshold as the optimal working frequency, and send the optimal working frequency to the capacitive active pen through the touch chip, and let the pen control chip connected by the capacitive active pen receive the optimal Working frequency information, and selecting the driving frequency according to the optimal operating frequency point, so as to avoid the interference signal generated by the display module, so that the use of the capacitive active pen is not affected by the strong interference signal. The occurrence of jitter or spurt also avoids the touch glitch that may be caused by the interference signal with less intensity, and ensures the normal operation of the capacitive active pen by the user. In addition, the use of the threshold setting avoids frequent switching between several frequency points where the interference signal strengths differ very little.

The above description is only an optional embodiment of the present invention, and the scope of the claims of the present invention is not limited thereto; any equivalent structure or equivalent process transformation made by using the description of the present invention and the contents of the drawings, or directly or indirectly applied to other related The technical field, or equivalent changes or modifications made without departing from the spirit of the invention, are intended to be included within the scope of the appended claims.

Claims

A touch panel is connected to a capacitive touch screen, the capacitive touch screen includes a plurality of driving electrode channels and a plurality of sensing electrode channels, wherein the touch chip includes a first control electrically connected to each other a unit, a driving circuit, a sensing circuit and a multiplexing unit, the first control unit driving the multiplexing unit to electrically connect the sensing circuit and the sensing electrode channel, the driving circuit is not Outputting any signal to the drive electrode channel, the first control unit driving the sensing circuit to detect a first signal from an object other than the capacitive touch screen and received by the sensing electrode channel, and to the first signal A signal is subjected to spectrum analysis to select a minimum intensity value of the first signal or a frequency point that differs from the minimum intensity value by less than a set threshold as a working frequency point.
The touch control chip according to claim 1, wherein the first control unit drives the multiplexing unit to electrically connect the driving circuit and the driving electrode channel, but the driving circuit does not output driving. A signal is sent to the drive electrode channel.
The touch control chip of claim 1 , wherein the object other than the capacitive touch screen further comprises a display module disposed at a distance from the sensing electrode channel, wherein the first signal further comprises A signal coupled to the sensing electrode channel by the display module.
The touch control chip according to claim 1, further comprising a minimum interference frequency selection unit electrically connected to the first control unit, wherein the first control unit drives the minimum interference frequency After the selection unit performs spectrum analysis on the first signal, the working frequency point is selected.
The touch control chip of claim 1 , wherein the capacitive touch screen is further touched by a capacitive active pen, and the first control unit drives the multiplexing unit to be electrically connected. The sensing electrode channel and the driving circuit, and driving the driving circuit to send a second signal loaded with the working frequency point information to the driving electrode channel and the sensing electrode channel and coupled to the capacitive active pen.
The touch control chip according to claim 5, wherein the transmission of one data bit is performed every time the second signal is transmitted at least twice.
The touch control chip according to claim 5, further comprising a modulation unit electrically connected to the first control unit, the first control unit driving the modulation unit to perform the work The frequency point information is loaded into the second signal.
The touch control chip according to claim 5, wherein the first control unit detects a third signal sent by the capacitive active pen, and detects a current periodic frequency of the third signal. The frequency of the third signal in the current period and the next period is alternately detected before the operating frequency point is different but the switching to the working frequency point.
The touch control chip according to claim 5, wherein the capacitive active pen comprises a control chip, the pen control chip comprises a second control unit electrically connected to each other, a tip electrode and a frequency a point switching unit, the second control unit sequentially driving the nib electrode to send a third signal to the capacitive touch screen, driving the nib electrode to detect and receive the second signal, and from the second signal Decomposing the working frequency point information, and driving the frequency point switching unit to switch a frequency point of the third signal sent in a next period from a current periodic frequency point to the working frequency point.
The touch control chip according to claim 9, wherein the pen control chip further comprises a demodulation unit electrically connected to the second control unit, and the second control unit drives the demodulation The unit decomposes the working frequency point information from the second signal.
The touch control chip according to claim 10, wherein the pen control chip further comprises a check unit electrically connected to the second control unit, and the second control unit drives the check The unit verifies the correctness of the working frequency point information decomposed from the second signal.
The touch control chip according to claim 9, wherein the first control unit drives the multiplexing unit to change the third signal when the third signal is sent to the capacitive touch screen The driving electrode channel and the sensing electrode channel are electrically connected to the sensing circuit, and driving the sensing circuit to detect the third signal, comparing the current periodic frequency point of the third signal with the working Frequency.
The touch control chip according to claim 12, wherein the first control unit drives the sensing circuit to detect that the detection frequency value of the third signal is equal to the second control unit to drive the nib electrode transmission station The transmission frequency value of the third signal.
The touch control chip according to claim 9, wherein the second control unit drives the nib electrode to detect the second signal once for a time equal to the first control unit to drive the driving circuit to transmit The time required for the second signal once.
The touch control chip according to claim 14, wherein the second control unit drives the nib electrode to detect the time required for each of the second signals to be 100 us.
A capacitive touch screen, comprising the touch chip according to any one of claims 1 to 15.
A capacitive active pen is characterized in that the capacitive active pen is in two-way communication with the capacitive touch screen according to claim 16.
A two-way communication method of a capacitive touch screen and a capacitive active pen, characterized in that the method comprises the following steps in each communication cycle:

The capacitive touch screen detects a first signal from the capacitive touch screen and the object except the capacitive active pen, and performs spectrum analysis on the first signal to select a minimum of the first signal An intensity value or a frequency point that differs from the minimum intensity value by less than a set threshold as a working frequency point;

When the capacitive active pen touches the capacitive touch screen, the capacitive touch screen loads the working frequency point information in a second signal;

When the capacitive active pen touches the capacitive touch screen, the capacitive touch screen detects a third signal sent by the capacitive active pen;

When the capacitive touch screen touches the capacitive touch screen, the capacitive touch screen determines that the current periodic frequency of the third signal is different from the working frequency, the capacitive touch screen sends the a second signal to the capacitive active pen;

When the capacitive active pen touches the capacitive touch screen, the capacitive active pen detects and receives the second signal, and decomposes the working frequency point information from the second signal;

When the capacitive active pen touches the capacitive touch screen, when the capacitive active pen determines that the current periodic frequency of the third signal is different from the working frequency, the capacitive active pen will be under The frequency of the third signal transmitted in one cycle is switched from the current periodic frequency point to the working frequency point.
The method of bidirectional communication between a capacitive touch screen and a capacitive active pen according to claim 18, wherein the method further comprises the following steps:

When the capacitive touch screen touches the capacitive touch screen, the capacitive touch screen determines that the current periodic frequency of the third signal is the same as the working frequency point, the capacitive touch screen continues to detect the The current periodic frequency of the third signal.
The method of bidirectional communication between a capacitive touch screen and a capacitive active pen according to claim 18, wherein the method further comprises the following steps:

When the capacitive touch screen touches the capacitive touch screen, the capacitive touch screen determines that the frequency of the third signal has not been switched from the current periodic frequency point to the working frequency point, the capacitance The touch screen detects the current periodic frequency point of the third signal in a current cycle, and detects a new frequency point of the third signal in a next cycle.
The method of bidirectional communication between a capacitive touch screen and a capacitive active pen according to claim 18, wherein the method further comprises the following steps:

When the capacitive active pen touches the capacitive touch screen, the capacitive active pen verifies the correctness of the working frequency point information decomposed from the second signal.