TW201704974A - Control method in touch display apparatus - Google Patents

Abstract

An exemplary embodiment of the present disclosure illustrates a control method in a touch display apparatus, wherein the touch display apparatus includes several pixel electrodes for displaying an image, and steps of the control method are described as follows. According to the image, a gain compensation value corresponding to N pixel electrodes of the pixel electrodes is obtained, wherein N is a positive integer larger than 0. Then, N pixel voltages are applied to the N pixel electrodes, and a capacitance variation of the N pixel electrodes is detected, wherein the N pixel voltages are generated according to the image. Next, the capacitance variation is compensated according to the gain compensation value, so as to obtain a capacitance sensing value, wherein touch information is calculated according to the capacitance sensing value.

Description

Control method of touch display device

The present invention relates to a touch display device, and more particularly to a touch display device for obtaining touch information using a pixel electrode of a general display device as an electrode unit without using an additional electrode unit, and a control method for using the same.

The existing touch display device has a touch display panel, and the touch display panel can be classified into an on-cell touch display panel or an in-cell touch display panel. The external touch display panel is formed by a display panel and a touch panel that are attached to each other, and the in-cell touch display panel uses a semiconductor process to integrate the display panel and the touch panel into a single panel.

The display panel has a plurality of pixel electrodes, and the plurality of pixel electrodes are respectively applied with a plurality of pixel voltages according to the image to be displayed currently, thereby displaying the image. The touch panel is configured with a plurality of electrode units to sense the amount of signals, and the controller connected to the touch display device can acquire touch information according to the amount of signals sensed by the electrode unit. Whether it is an external touch display panel or an in-cell touch display panel, it is necessary to set an additional electrode unit to sense the signal amount.

The embodiment of the invention provides a method for controlling a touch display device, wherein the touch display device includes a plurality of pixel electrodes to display images, and the steps of the control method are as follows. Obtaining corresponding to N pixel electrodes of the plurality of pixel electrodes according to the image Gain compensation value, where N is a positive integer greater than or equal to one. Then, N pixel voltages are applied to the N pixel electrodes, and the capacitance variation of the N pixel electrodes is detected, wherein the N pixel voltages are generated according to the image. Then, the capacitance variation amount is compensated according to the gain compensation value to obtain a capacitance sensing value, wherein the capacitance sensing value is used to calculate the touch information.

The embodiment of the invention further provides a touch display device, which comprises a plurality of pixel electrodes and a control unit, wherein the control unit is configured to execute the above control method.

In summary, the control display device can use the display panel as the touch display panel, that is, the electrode unit is not additionally added for touch detection, thereby reducing the thickness and manufacturing cost of the touch display device.

For a fuller understanding of the features and technical aspects of the present invention, the invention will be understood by The invention is not intended to limit the scope of the invention.

1, 1', 1", 1'''‧‧‧ touch display device

11‧‧‧Source drive circuit

12‧‧‧ gate drive circuit

13‧‧‧Self-sensing circuit

131‧‧‧Compensation unit

132‧‧‧Transition unit

14‧‧‧Touch display panel

15, 15', 15", 15'''‧‧‧ Gain Compensation Value Generator

16‧‧‧Display circuit

151‧‧‧Correction unit

152‧‧‧ averaging unit

153‧‧‧ Gain compensation value generating unit

2‧‧‧pixel unit

ADC‧‧‧ Analog Digital Converter

AMP‧‧Amplifier

BM‧‧‧Light shielding layer

CF‧‧ color filter

C _I ‧‧‧Induction Capacitance

COM‧‧‧Common electrode

DP‧‧‧ display substrate

FG‧‧ fingers

_{G 1 ~ G 5, G i} ‧‧‧ gate line

GL‧‧‧glass substrate

LC‧‧‧Liquid layer

PE _1,1 , PE _1,2 , PE _1,3 , PE _1,4 , PE _i,j ‧‧‧pixel electrode

S ₁ ~S ₄ , S _j ‧‧‧ data line

S41~S43‧‧‧Step procedure

TFT‧‧‧thin film transistor

FIG. 1A is a schematic circuit diagram of a touch display device according to an embodiment of the invention.

FIG. 1B is a schematic circuit diagram of a touch display device according to another embodiment of the present invention.

FIG. 1C is a schematic circuit diagram of a touch display device according to another embodiment of the present invention.

FIG. 1D is a schematic circuit diagram of a touch display device according to another embodiment of the present invention.

2 is a schematic diagram showing the layout of a pixel unit of the touch display device according to the embodiment of the invention.

3 is a cross-sectional view of a touch display panel of a touch display device according to an embodiment of the invention.

4 is a schematic flow chart of a control method for a touch display device according to an embodiment of the present invention.

Embodiments of the present invention provide a touch display device and a control method used by the touch display device. Through the control method, the touch display device can apply N pixel voltages to display image images at N pixel electrodes, and simultaneously sense capacitance variation of N pixel electrodes, where N is a positive integer greater than or equal to 1. That is, during the period when the gate line is enabled, a plurality of pixel electrodes on the gate line are applied with a plurality of pixel voltages, and each of the N pixel electrodes is selected as an electrode unit to sense The amount of capacitance change of each electrode unit was measured. Since the resolution of the touch display device is high and the distance between the electrodes of the pixels is small, if the object such as a finger or a stylus is to be detected when used for the purpose of the touch detection, N can correspond to The object size is selected to be greater than or equal to 2, that is, two or more pixel electrodes are selected as one electrode unit; if the fingerprint is to be identified, N can be selected as a smaller number such as 1 or 2 for fingerprint identification. the use of.

Since the plurality of pixel electrodes are respectively applied with different pixel voltages according to the images, it is necessary to calculate the gain compensation values of the N pixel electrodes in the same electrode unit according to the images in advance, after sensing the capacitance variation amount per N pixel electrodes. And sensing the capacitance change amount according to the corresponding gain compensation value, thereby obtaining a capacitance sensing value of each electrode unit, wherein the capacitance sensing value can be used to calculate touch information, wherein the touch information can be used for finger touch Touch detection or fingerprint recognition.

Since the touch display device applies N pixel voltages to display images in N pixel electrodes, and simultaneously senses the capacitance change amount of the N pixel electrodes, the touch display device does not need to be additionally disposed. The electrode unit of the touch information is obtained, and the touch display device can be implemented by using a general display device.

1A is a schematic circuit diagram of a touch display device according to an embodiment of the invention. The touch display device 1A includes a control unit and a touch display panel 14 . The control unit includes a source driving circuit 11, a gate driving circuit 12, a self-capacitance sensing circuit 13, a gain compensation value generator 15, and a display circuit 16. The display circuit 16 is electrically connected to the source driving circuit 11, the gate driving circuit 12, and the gain compensation value generator 15. The gate driving circuit 12 is electrically connected to the touch display panel 14 through the plurality of gate lines G ₁ to G ₅ , and the source driving circuit 11 and the self-capacitance sensing circuit 13 are electrically connected to the plurality of data lines S ₁ to S ₄ . The touch display panel 14 is connected.

The touch display panel 14 includes a plurality of pixel units and a common electrode COM, wherein the plurality of gate lines G ₁ G G _{5 are} electrically insulated from the plurality of data lines S ₁ -S ₄ . Each of the pixel units includes a thin film transistor TFT and a pixel electrode PE _i,j , and a drain of the thin film transistor TFT of each pixel unit is electrically connected to the pixel electrode PE _i,j . The gates of the pixel pads of the pixel units of the same column are electrically connected to the same gate line G _i , and the source of the thin film pad transistor TFT of the pixel unit of the same row is electrically connected to the same data line S _j , wherein i is, for example, an integer of 1 to 4, and j is, for example, an integer of 1 to 5. The touch display panel 14 is not additionally provided with an electrode unit for touch detection, but is a general display panel.

The display circuit 16 is configured to provide pixel data of the image to the source driving circuit 11, the gate driving circuit 12, and the gain compensation value generator 15, so that the source driving circuit 11, the gate driving circuit 12, and the gain compensation value generator 15 are based on the image. The pixel data implements the corresponding function.

The source driving circuit 11 receives the pixel data of the image, and generates a pixel voltage corresponding to the pixel electrode PE _i,j according to the image, so that the pixel electrode PE _i,j can display the pixel of the i-th column and the jth row of the image. In general, the source driver circuit 11 performs gamma correction on the pixel data to generate a corresponding plurality of pixel voltages. The gate driving circuit 12 is configured to enable the gate line G _i to select the pixel electrodes PE _i,1 -PE _i,4 of the pixel unit electrically connected to the gate line G _i .

When the source driving circuit 11 receives the pixel data of the image, the gain compensation value generator 15 also receives the pixel data of the image, and generates N pixel electrodes PE _i,j ~PE _i,j+N selected as the electrode unit. The gain compensation value corresponding to _-1 . Therefore, when the self-capacitance sensing circuit 13 senses the capacitance change amount of the N pixel electrodes PE _i,j ~PE _i,j+N-1 , the capacitance variation amount is compensated according to the gain compensation value, and A capacitance sensing value of the N pixel electrodes PE _i,j ~PE _{i,j+N-1 is} generated, wherein the capacitance sensing value can be used to calculate the touch information.

In this embodiment, N may be 2, and the two pixel electrodes PE _i,1 , PE _i,2 located on the gate line G _i and corresponding to the data lines S ₁ and S ₂ respectively may be selected as one electrode unit ( Hereinafter, the first electrode unit is referred to as the first electrode unit, and the two pixel electrodes PE _{i, 3} , PE _{i, 4} located on the gate line G _i and corresponding to the data lines S ₃ and S ₄ respectively may be selected as the other electrode unit (hereinafter referred to as Referred to as the second electrode unit). The gain compensation value generator 15 calculates the gain compensation values corresponding to the above two electrode units, respectively.

When the gate line G _i is enabled, the pixel electrodes PE _i,1 -PE _i,4 corresponding to the data lines S ₁ -S ₄ on the gate line G _i are respectively applied with corresponding four pixel voltages, The amount of change in capacitance of the pixel electrodes PE _i,1 , PE _{i,2 and} the amount of change in capacitance of the pixel electrodes PE _i,3 , PE _i,4 are sensed. Then, the self-capacitance sensing circuit 13 compensates the capacitance variation of the pixel electrodes PE _i,1 , PE _{i,2 and} the capacitance variation of the pixel electrodes PE _i,3 ,PE _i,4 according to the two calculated gain compensations, respectively. The values are compensated to thereby obtain capacitance sensing values of the first and second electrode units.

One of the implementations of the self-capacitance sensing circuit 13 is further described below. However, the implementation of the self-capacitance sensing circuit 13 is not intended to limit the present invention. In this embodiment, the self-capacitance sensing circuit 13 includes a compensation unit 131 and a conversion unit 132, wherein the compensation unit 13 is electrically connected to all of the data lines S ₁ to S ₄ , the gain compensation value generator 15 and the conversion unit 132 .

The compensation unit 131 includes a plurality of amplifiers AMP, wherein each of the amplifiers AMP is configured to receive a capacitance change amount of the corresponding pixel electrode PE _i,j and compensate the received capacitance change amount according to the received gain compensation value. The converting unit 132 includes a plurality of analog-to-digital converter ADCs, wherein each of the analog-to-digital converters ADC is electrically connected to the corresponding amplifier AMP for analog-to-digital conversion of the compensated capacitance change amount.

In addition, the self-capacitance sensing circuit 13 further includes an arithmetic circuit (not shown in FIG. 1A) for converting the capacitance change amount of the digital pixel electrode PE _i,j , PE _i,j+N-1 into a capacitance sensing value. As the touch information corresponding to the first electrode unit. Then, the touch circuit (not shown in FIG. 1A ) in the self-capacitance sensing circuit 13 performs a corresponding touch function according to the capacitance sensing value.

One of the implementations of the gain compensation value generator 15 is further described below, however, the implementation of the gain compensation value generator 15 is not intended to limit the invention. In this embodiment, the gain compensation value generator 15 includes a correction unit 151, an averaging unit 152 and a gain compensation value generation unit 153, wherein the correction unit 151 is electrically connected to the averaging unit 152, and the gain compensation value generation unit 153 is electrically connected to the average The unit 152 and the compensation unit 131 of the self-capacitance sensing circuit 13.

Incidentally, in this embodiment, the gain compensation value generator 15 is independent of the self-capacitance sensing circuit 13 and the display circuit 16. However, the invention is not limited thereto. In other embodiments, the gain compensation value generator 15 may be included in the self-capacitance sensing circuit 13 or the display circuit 16.

The correcting unit 151 is configured to receive the pixel data of the image to correct the pixel data of the image, wherein the correction corresponds to the correction performed by the source driving circuit 11 on the pixel data of the image. For example, the source driving circuit 11 performs gamma correction on the pixel data of the image, so the correcting unit 151 also needs to perform gamma correction on the pixel data of the image to generate the pixel electrodes PE _i,j , PE _i,j+ The pixel voltage of _N-1 . Then, average unit 152 will be the pixel electrode _{PE i, j, PE i,} j + _N-1 of the pixel voltage for general or weighted average calculation to obtain the pixel electrode _{PE i, j, PE i,} j + N-1 of Average voltage value.

Thereafter, the gain compensation value generating unit 153 receives the pixel electrode _{PE i, j, PE i,} j + N-1 average voltage value to generate a corresponding pixel electrode _{PE i, j, PE i,} j + N-1 gain The compensation value, wherein the higher the pixel voltage of the pixel electrode PE _i,j , PE _i,j+N-1 , the lower the corresponding gain compensation value, and conversely, the pixel electrode PE _i,j ,PE _i,j+N The lower the pixel voltage of _-1 , the higher the corresponding gain compensation value. For example, the gain compensation value generating unit 153 may be, for example, a reciprocal calculation unit for calculating the reciprocal of the average voltage value of the pixel electrodes PE _i,j , PE _i,j+N-1 as the electrode unit Corresponding gain compensation value. However, the present invention is not limited to the implementation of the gain compensation value generating unit 153.

With the above example of N being 2, the averaging unit 152 calculates the average voltage value of the pixel voltages of the pixel electrodes PE _i,1 , PE _i,2 , and calculates the average of the pixel voltages of the pixel electrodes PE _i,3 , PE _i,4 . Voltage value. Then, the gain compensation value generating unit 153 calculates the reciprocal of the average voltage value of the pixel voltages of the pixel electrodes PE _i,1 , PE _i,2 , and calculates the average voltage of the pixel voltages of the pixel electrodes PE _i,3 , PE _i,4 . The reciprocal of the values to thereby generate gain compensation values for the first and second electrode units.

1B, FIG. 1B is a schematic circuit diagram of a touch display device according to another embodiment of the present invention. Compared with the touch display device 1 of FIG. 1A, the gain compensation value generator 15' in the touch display device 1' of FIG. 1B does not have an averaging unit. The embodiment of FIG. 1B is only used when N is 1, that is, each electrode unit contains only one pixel electrode PE _i,j , and the gain compensation value generating unit 153 calculates the reciprocal of the pixel voltage of the pixel electrode PE _i,j . To generate a gain compensation value corresponding to the electrode unit.

1C, FIG. 1C is a schematic circuit diagram of a touch display device according to another embodiment of the present invention. Compared with the touch display device 1 of FIG. 1A , the gain compensation value generator 15 ′ in the touch display device 1 ′ of FIG. 1C does not receive the pixel data of the image, but separately acquires each pixel electrode from the source driving circuit 11 . The pixel voltage of PE _i,j , and thus the gain compensation value generator 15" does not have a correction unit.

Moreover, please refer to FIG. 1D. FIG. 1D is a schematic circuit diagram of a touch display device according to another embodiment of the present invention. Compared with the touch display device 1" of FIG. 1C, the gain compensation value generator 15"' in the touch display device 1"' of FIG. 1D does not have an averaging unit. The embodiment of FIG. 1D is only used for N 1, each electrode unit is only one pixel electrode PE _{i, j,} and the gain is a compensation value generating unit 153 calculates the pixel electrode PE _{i, j is} the reciprocal of the pixel voltage, to produce a corresponding pixel electrode PE _{i, j} Gain compensation value.

Please note that the touch display panel 14 of FIGS. 1A-1D may be a lateral electric field effect (IPS) display panel, that is, the touch display device 1 is a lateral electric field effect display device, wherein the layout of each pixel unit is as follows: . However, the present invention is not limited to the type of the touch display panel 14 of the touch display device 1.

Please refer to FIG. 2. FIG. 2 is a schematic diagram showing the layout of a pixel unit of the touch display device according to the embodiment of the present invention. 2 in the pixel unit, the gate line G _i and the data line S _j located at different layers, and not electrically connected to each other. The pixel electrodes PE _{i,j are} located in the same layer as the data lines S _j but are in different layers from the common electrode COM and are not electrically connected to each other, and can form a transverse electric field when there is a voltage difference between each other. The gate, the source and the drain of the thin film transistor TFT are electrically connected to the gate line G _i , the data line S _j and the pixel electrode PE _{i,j , respectively} .

Note here that FIG. 2 is only one arrangement of a pixel unit of Embodiment 2, and the present invention is not limited pixel layout means 2, i.e., does not limit the pixel electrode PE _{i, j} S _j and the data line in the same layer, The pixel electrode PE _i,j is not limited to be in a different layer from the common electrode COM, and other pixel arrangements in which the pixel electrode PE _i,j can cause a capacitive coupling effect with the object in contact can be applied to the present invention.

Since the above embodiment selects at least one pixel electrode PE _i,j as at least one electrode unit for performing touch detection, the pixel electrode PE _i,j itself needs to be capable of capacitive coupling effect with the object being touched. . The pixel electrode PE _i,j in the lateral field effect display panel is not shielded by itself, and the object that can be touched can generate a capacitive coupling effect, so that it can be used to implement the touch display device of the embodiment of the invention. However, the present invention does not limit the touch display panel 14 of the touch display device to be only a lateral electric field effect display panel, and the other pixel electrodes PE _{i,j are} not shielded and can display capacitive coupling effects with the adjacent objects. The touch display panel 14 can be implemented.

Next, the stack structure of the lateral electric field effect display panel is further explained. Please refer to FIG. 3. FIG. 3 is a cross-sectional view of a touch display panel of a touch display device according to an embodiment of the invention. In FIG. 3 , the touch display panel 14 is a lateral electric field effect display panel, and includes a display substrate DP, a liquid crystal layer LC, a color filter CF, a light shielding layer BM, and a glass substrate GL. The liquid crystal layer LC is located between the display substrate DP and the color filter CF, and the glass substrate GL is located above the color filter. A non-visible area is defined around the glass substrate GL, and a light shielding layer BM is disposed between the non-visible area and the color filter CF.

The display substrate DP has a gate line (not shown in FIG. 3), a data line S _j , a pixel electrode PE _{i, j} and a common electrode COM. The gate line, the data line S _j and the common electrode COM are located at different layers of the display panel DP and are not electrically connected to each other. The pixel electrode PE _i,j and the data line S _{j are} located on the same layer of the display panel DP, but are not electrically connected to each other. When the pixel electrode PE _i,j is applied with the pixel voltage, the pixel electrode PE _i,j and the common electrode COM generate a lateral electric field to affect the deflection of the liquid crystal in the liquid crystal layer LC, thereby displaying the corresponding image.

Please note that the pixel electrode PE _i,j is not obscured by other conductors. Therefore, when an object (for example, a finger FG) approaches the touch display panel 14, the finger FG can generate a capacitance field with the pixel electrode PE _i,j. The coupling effect, and a sensing capacitor C _I is derived between each other. Therefore, the pixel electrode PE _i,j can be selected as the electrode unit to sense the signal amount representing the change of the capacitance, and the touch display device can obtain the touch information of the finger FG through the signal amount.

Next, please refer to FIG. 4. FIG. 4 is a schematic flow chart of a control method for a touch display device according to an embodiment of the present invention. The control method may be implemented in the control unit of the touch display device of the embodiment of FIG. 1A to FIG. 1D, and the invention is not limited thereto.

First, in step S41, the gain compensation value generator obtains a gain compensation value corresponding to the N pixel electrodes according to the image, where N is a positive integer greater than or equal to 1. In step S41, the gain compensation value generator can directly obtain the pixel voltages of the N pixel electrodes generated by the source driving circuit; or the gain compensation value generator receives the pixel data of the image, and performs gamma correction on the pixel data to obtain The pixel voltage of the N pixel electrodes. Then, if N is equal to 1, the reciprocal of the pixel voltage is directly calculated to obtain a gain compensation value; if N is greater than 1, the average voltage of the pixel voltages of the N pixel electrodes is calculated first, and then the reciprocal of the average electric voltage is calculated. Get the gain compensation value.

Then, in step S42, the source driving circuit applies N pixel voltages to the N pixel electrodes, and the self-capacitance sensing circuit detects the capacitance change amount of the N pixel electrodes, wherein the N pixel voltages are generated according to the image. Furthermore, in step S43, the self-capacitance sensing circuit changes the capacitance of the N pixel electrodes according to the gain compensation value. Compensation is performed to obtain a capacitance sensing value, wherein the capacitance sensing value is used to calculate touch information.

In summary, the control display device and the control method of the control display device according to the embodiments of the present invention sense and compensate the capacitance change of the pixel electrode when the pixel electrode is applied with the pixel voltage to display the image. The capacitance sensing value is obtained, and the capacitive sensing value is used to obtain the touch information. The touch display device can use the display panel as the touch display panel, that is, the electrode unit is not additionally added for touch detection, thereby reducing the thickness and manufacturing cost of the touch display device.

The above is only the embodiment of the present invention, and is not intended to limit the scope of the present invention. The present invention has been disclosed by the embodiments, but is not intended to limit the invention, and any one of ordinary skill in the art, In the scope of the technical solutions of the present invention, equivalent modifications may be made to the equivalents of the embodiments of the present invention without departing from the technical scope of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments are still within the scope of the technical solutions of the present invention.

S41~S43‧‧‧Steps

Claims (13)

A touch display device includes a plurality of pixel electrodes for displaying an image. The control method includes: Step a: obtaining N pixel electrodes of the pixel electrodes according to the image Corresponding a gain compensation value, wherein N is a positive integer greater than or equal to 1; step b: applying N pixel voltages to the N pixel electrodes, and detecting a capacitance change amount of the N pixel electrodes, wherein the N pixels The voltage is generated according to the image; and step c: compensating the capacitance variation according to the gain compensation value to obtain a capacitance sensing value, wherein the capacitance sensing value is used to calculate a touch information. The control method of the touch display device according to claim 1, wherein the N pixel electrodes are connected to the same gate line, and the step b is performed to enable the gate lines connected to the N pixel electrodes to be enabled. During the period. The control method of the touch display device of claim 1, wherein in the step a, the gain compensation value is calculated according to the N pixel voltages, wherein the higher the pixel voltage, the gain compensation value The lower the pixel voltage is, the higher the gain compensation value is. The method for controlling a touch display device according to claim 3, wherein the N pixel voltages are obtained by using a gamma correction according to a pixel data of the image. The method for controlling a touch display device according to claim 4, wherein in the step a, an average voltage value of the N pixel voltages is calculated, and the gain compensation value is calculated according to the average voltage value. The method of controlling a touch display device according to claim 1, wherein the touch display device is a lateral electric field effect (IPS) display device. A touch display device includes: a plurality of pixel electrodes for displaying an image; and a control unit for performing: step a: obtaining N pixels of the pixel electrodes according to the image a gain compensation value corresponding to the pole, wherein N is a positive integer greater than or equal to 1; step b: applying N pixel voltages to the N pixel electrodes, and detecting a capacitance change amount of the N pixel electrodes, wherein the N The pixel voltage is generated according to the image; and step c: compensating the capacitance variation according to the gain compensation value to obtain a capacitance sensing value, which is used to calculate a touch information. The touch display device of claim 7, wherein the N pixel electrodes are connected to the same gate line, and the step b is performed during a period in which the gate lines of the N pixel electrode connections are activated. The touch display device of claim 7, wherein in the step a, the gain compensation value is calculated according to the N pixel voltages, wherein the higher the pixel voltage, the lower the gain compensation value is. And the lower the pixel voltage, the higher the gain compensation value. The touch display device of claim 9, further comprising a gain compensation value generator, wherein in the step a, the gain compensation value generator obtains a pixel data of the image by using a gamma correction The N pixel voltages. The touch display device of claim 10, wherein in the step a, an average voltage value of the N pixel voltages is calculated by the gain compensation value generator, and the gain is calculated according to the average voltage value Compensation value. The touch display device of claim 9, further comprising a source driving circuit, wherein in the step b, the source driving circuit uses a gamma correction to obtain the N according to the pixel data of the image. Pixel voltage. The touch display device of claim 7, wherein the touch display device is a lateral electric field effect display device.