CN111913610A

CN111913610A - Touch display panel and touch coordinate acquisition method

Info

Publication number: CN111913610A
Application number: CN202010783558.7A
Authority: CN
Inventors: 宋聚仁
Original assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; General Interface Solution Ltd
Current assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; General Interface Solution Ltd
Priority date: 2020-08-06
Filing date: 2020-08-06
Publication date: 2020-11-10
Anticipated expiration: 2040-08-06
Also published as: TWI737445B; CN111913610B; TW202206993A

Abstract

The invention provides a touch display panel, which is defined with a display area and a non-display area, wherein the non-display area surrounds and is adjacent to the edge of the display area; the touch display panel includes: the touch electrodes are arranged in the display area at intervals; a plurality of detection lines located in the non-display area; the controller is positioned in the non-display area and is electrically connected with the detection lines and the touch control electrodes; the controller is used for outputting detection signals to the detection lines to detect the conductivity of the internal circuit of the touch display panel, outputting touch driving signals to the detection lines and the touch electrodes, and receiving touch sensing signals returned by the detection lines and the touch electrodes according to the touch driving signals to acquire touch coordinates. The invention further provides a touch coordinate obtaining method.

Description

Touch display panel and touch coordinate acquisition method

Technical Field

The invention relates to the technical field of touch control, in particular to a touch control display panel and a touch control coordinate acquisition method applied to the touch control display panel.

Background

The display device is provided with the touch electrode to realize human-computer interaction. In the external display device, a display panel and a touch panel are independent from each other, the display panel has a display area, and the touch panel includes a touch electrode. The touch electrode in the touch panel can extend out of the display area of the display panel, so that the touch precision of the edge part of the display area is improved. However, in the display device, the touch electrode is embedded in the display panel and cannot extend to the outside of the display area, which results in a decrease in touch accuracy at the edge of the display area.

Disclosure of Invention

The invention provides a touch display panel, which is defined with a display area and a non-display area, wherein the non-display area surrounds and is adjacent to the edge of the display area; the touch display panel includes:

the touch electrodes are arranged in the display area at intervals;

a plurality of detection lines located in the non-display area; and

the controller is positioned in the non-display area and is electrically connected with the detection lines and the touch control electrodes;

the controller is used for outputting detection signals to the detection lines to detect the conductivity of the internal circuit of the touch display panel, outputting touch driving signals to the detection lines and the touch electrodes, and receiving touch sensing signals returned by the detection lines and the touch electrodes according to the touch driving signals to acquire touch coordinates.

The invention provides a touch coordinate acquisition method, which is applied to a touch display panel, wherein the touch display panel comprises a plurality of touch electrodes and a plurality of detection lines; the touch control method comprises the following steps:

acquiring first touch sensing signals on the touch electrodes, calculating a first coordinate according to the first touch sensing signals, and judging whether the first coordinate is an edge coordinate;

if the touch control coordinate is judged to be the touch control coordinate, second touch control induction signals on the detection lines are obtained, the first coordinate is corrected according to the second touch control induction signals to obtain a second coordinate, and the second coordinate is defined as the touch control coordinate;

if not, defining the first coordinate as a touch coordinate.

According to the touch display panel, the sensing capacitance between the detection line and the touch object (such as a finger and a touch pen) is used as the touch sensing signal, so that more accurate touch coordinates can be obtained, and the problem that the touch coordinate calculation is inaccurate when the touch position is at the edge of the touch display panel is solved; in addition, the touch display panel utilizes the originally existing detection lines, and no new element is added, so that the manufacturing cost of the touch display panel is well controlled on the basis of improving the accuracy of touch coordinates.

Drawings

Fig. 1 is a schematic cross-sectional view of a touch display panel according to an embodiment of the invention.

Fig. 2 is a schematic plane structure diagram of a thin film transistor array substrate according to an embodiment of the invention.

Fig. 3 is another schematic plan view of a tft array substrate according to an embodiment of the invention.

Fig. 4 is a flowchart illustrating a touch coordinate obtaining method according to an embodiment of the present invention.

Fig. 5 is a schematic diagram of a coordinate system on a tft array substrate according to an embodiment of the present invention.

Fig. 6 is a schematic diagram illustrating capacitance variation of the touch electrode when the touch display panel is touched at a first position according to a comparative example.

Fig. 7 is a schematic diagram illustrating capacitance variation of the touch electrode when the touch display panel is touched at a second position according to a comparative example.

Description of the main elements

Touch display panels

10, 50

Color film substrate 20

Thin film transistor array substrate 30

Display areas

31, 51

Sub-pixels

311R, 311G, 311B

Non-display

areas

32, 53

Touch electrode

33, 52, 520

Detection lines

34R, 34G, 34B

Controller 35

First switch circuit 36

Second switch circuit 37

First switching element 38

Second switching element 39

Liquid crystal layer 40

Liquid crystal molecules 41

Line coordinates X, x₀

Column coordinates Y, Y₀

Finger 60

Touch control pen 70

The following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

Referring to fig. 1, a touch display panel 10 includes a color filter substrate 20, a thin film transistor array substrate 30 disposed opposite to the color filter substrate 20, and a liquid crystal layer 40 disposed between the color filter substrate 20 and the thin film transistor array substrate 30. The liquid crystal layer 40 includes liquid crystal molecules 41 densely arranged therein. When a voltage difference is formed between the color filter substrate 20 and the thin film transistor array substrate 30, the liquid crystal molecules 41 rotate. The difference in the voltage varies, and the rotation angle of the liquid crystal molecules 41 varies. The touch display panel 10 can be controlled to display different images by controlling the change of the voltage difference of each pixel region. One side of the touch display panel 10 displaying the image is the side of the color film substrate 20 away from the thin film transistor array substrate 30. The touch display panel 10 further includes other necessary components, and only some of the components are described in this embodiment.

Referring to fig. 1 and 2, the tft array substrate 30 defines a display area 31 (e.g., an area surrounded by an outermost dotted line in fig. 2) and a non-display area 32 (e.g., an area surrounded by an outermost solid line and an outermost dotted line in fig. 2) adjacent to each other, and the non-display area 32 surrounds an edge of the display area 31. The display area 31 is an area where the touch display panel 10 can display images during operation. The non-display area 32 is an area where the touch display panel 10 cannot display images during operation, and is generally used for disposing elements made of opaque materials (such as metal, plastic, etc.) in the touch display panel 10, such as various fan-out lines, etc. The frame is usually disposed to cover the non-display area 32 to improve the aesthetic property of the touch display panel.

The display area 31 defines a plurality of sub-pixels arranged in an array comprising a plurality of rows and a plurality of columns, of which only a 3 x 6 array is schematically shown in fig. 2 for clarity of illustration, although in particular embodiments the array of sub-pixels may comprise more rows and more columns. The plurality of sub-pixels include a plurality of sub-pixels 311R emitting red light, a plurality of sub-pixels 311G emitting green light, and a plurality of sub-pixels 311B emitting blue light. In this embodiment, the

sub-pixels

311R, 311G, 311B are alternately arranged in the row direction, and the sub-pixels in the same column are the sub-pixels emitting the same color light. In other embodiments, the arrangement of the sub-pixels may be different. A region of the thin film transistor array substrate 30 corresponding to each sub-pixel is provided with a thin film transistor, a pixel electrode, and the like (not shown) to display an image.

In this embodiment, the thin film transistor array substrate 30 has a substantially rectangular shape, and the display region 31 has a substantially rectangular shape. In other embodiments, the tft array substrate 30 and the display area 31 may have other shapes, such as a circle, an ellipse, or other irregular shapes.

The thin film transistor array substrate 30 further includes three sensing lines positioned in the non-display area 32, and a controller 35 positioned in the non-display area 32. The three detection lines are

detection lines

34R, 34G, and 34B, respectively. The detection lines 34R, 34G, and 34B are electrically connected to the controller 35, respectively. Detection line 34R is also electrically connected to elements (e.g., pixel electrodes, thin film transistors, etc.) in each sub-pixel 311R, detection line 34G is also electrically connected to elements in each sub-pixel 311G, and detection line 34B is also electrically connected to elements in each sub-pixel 311B.

The number of detection lines is the same as the number of types of sub-pixels, which emit light of different colors. Three types of sub-pixels are included in this embodiment: the sub-pixels 311R, 311G, 311B, therefore, include three detection lines in this embodiment. In other embodiments, the number of the sub-pixel types may be four, and compared to the embodiment, the sub-pixel emitting white light is further added, and the sub-pixel comprises four detection lines, and each detection line is electrically connected to one sub-pixel.

Referring to fig. 3, the tft array substrate 30 further includes a plurality of first switch lines 36 and second switch lines 37 in the non-display area 32. The first switch lines 36 are electrically connected to the elements in each row of sub-pixels, respectively. The second switch lines 37 are electrically connected to the elements in each column of sub-pixels, respectively.

In this embodiment, the controller 35 is located at one side of the display area 31, and the

detection lines

34R, 34G, and 34B, the first switch line 36, and the second switch line 37 surround the remaining three sides of the display area 31. As shown in fig. 2 and 3, the controller 35 is located in a lower frame region of the touch display panel 10 when the viewing surface faces the viewer.

In this embodiment, the touch display panel 10 further includes a plurality of first switch elements 38 and a plurality of second switch elements 39. The detection lines 34R, 34G, and 34B and the first switch line 36 are electrically connected to the elements in the sub-pixels via the plurality of first switch elements 38. The second switch line 37 electrically connects elements within the sub-pixels through the plurality of second switch elements 39. The first switching element 38 and the second switching element 39 are thin film transistors. The gate of each first switch element 38 is electrically connected to the first switch line 36, and the first switch line 36 is used for controlling whether the source and the drain of each first switch element 38 are conducted or not. One of the source and the drain of each first switching element 38 is electrically connected to an element in the sub-pixel, and the other is electrically connected to a detection line (34R, 34G, or 34B). The gate of each second switch element 39 is electrically connected to the first switch line 36, and the first switch line 36 is used for controlling whether the source and the drain of each second switch element 39 are conducted. One of the source and the drain of each second switching element 39 is electrically connected to the element in the sub-pixel, and the other is electrically connected to the second switching line 37.

The detection lines 34R, 34G, and 34B, the first switch line 36, and the second switch line 37 are mutually matched, and are used for testing the conductivity of the lines (e.g., data lines, gate lines, etc.) in the thin film transistor array substrate 30 during the manufacturing process of the touch display panel 10 (after the thin film transistor array substrate 30 and the color filter substrate 20 are assembled). The first switch line 36 inputs a voltage signal to control the first switch element 38 and the second switch element 39 to be turned on, the source and the drain of the first switch element 38 are turned on, the source and the drain of the second switch element 39 are turned on, and the controller 35 inputs a gate scan detection signal to the elements in each sub-pixel through the first switch line 36 and inputs an image detection signal to the elements in each sub-pixel through the second switch line 37. If the elements in each sub-pixel work normally, the circuit can be judged to have no fault; if the operation of the element in each sub-pixel is abnormal, the correction can be performed in time.

After the detection is completed, the first switch circuit 36 inputs a voltage signal to control the first switch element 38 and the second switch element 39 to keep off, so as to avoid affecting the display image of the touch display panel 10.

Referring to fig. 1 and 3, the tft array substrate 30 includes a plurality of touch electrodes 33. The touch electrodes 33 are disposed on the surface of the thin film transistor array substrate 30 close to the color filter substrate 20. The touch electrodes 33 are located in the display area 31. The touch display panel 10 adopts a self-contained touch manner, and the touch electrodes 33 are arranged at intervals in an array including a plurality of rows and a plurality of columns. The touch electrode 33 is made of a transparent conductive material, such as indium tin oxide.

The touch display panel 10 provided in this embodiment is an in-cell (in-cell) touch display panel, and the touch electrodes 33 are disposed in the display area 31. When an object (e.g., a finger) touches an edge of the display area 31 on the touch display panel 10, an area of the touch electrode 33 directly opposite to the finger (a projection area of the finger on the touch electrode 33) is small, and an error occurs in a touch sensing signal on the touch electrode 33 caused by the finger, which easily causes inaccuracy in a calculated touch coordinate.

The present embodiment utilizes the

detection lines

34R, 34G and 34B to solve the problem of inaccurate touch coordinates. Specifically, the

detection lines

34R, 34G, and 34B are also conductive structures, and when a conductive object such as a finger touches the positions of the

detection lines

34R, 34G, and 34B, touch sensing signals can be generated on the

detection lines

34R, 34G, and 34B, in this embodiment, the

detection lines

34R, 34G, and 34B are also used as touch electrodes to read the touch sensing signals thereon for calculating touch coordinates. This corresponds to adding touch electrodes (

detection lines

34R, 34G, and 34B) in the non-display area 32 of the touch display panel 10. The areas corresponding to the touch electrodes 31 in the display area 31 can be defined as the initial touch sensing areas of the display panel, and the areas corresponding to the

detection lines

34R, 34G, and 34B in the non-display area 32 can be defined as the extended touch sensing areas. In this embodiment, the extended touch sensing area is added on the basis of the initial touch sensing area, and since the extended touch sensing area is located in the non-display area 32 and the non-display area 32 is disposed around the periphery of the display area 31, the touch sensing accuracy at the edge of the display area 31 is improved.

The present embodiment provides a touch coordinate obtaining method, which is applied to the touch display panel 10, and the touch coordinate obtaining method (i.e. the working process of the touch display panel 10 when implementing the touch function) is explained below.

Referring to fig. 4, in step S1, first touch sensing signals on the touch electrodes are obtained, and a first coordinate is calculated according to the first touch sensing signals.

Step S2, determining whether the first coordinate is an edge coordinate.

If yes, step S3 is executed to obtain a second touch sensing signal on the detection lines, modify the first coordinate according to the second touch sensing signal to obtain a second coordinate, and define the second coordinate as a touch coordinate.

If not, go to step S4 to define the first coordinate as a touch coordinate.

Referring to fig. 3 and 4, in step S1, the controller 35 outputs touch driving signals to each touch electrode 33 and each

detection line

34R, 34G, and 34B. Each touch electrode 33 generates a touch sensing signal according to the touch driving signal. In this embodiment, the touch display panel 10 adopts a self-capacitance touch method, and each touch electrode 33 has an initial capacitance (a capacitance when the touch display panel 10 is not touched). When there is an object (finger, stylus, etc.) touching, the capacitance value on the touch electrode 33 at the position where the object touches changes, and the change amount of the capacitance is the first touch sense signal. The touch electrode 33 can transmit the touch sensing signal back to the controller 35.

Further, whether the first touch sensing signal is larger than a first threshold value is judged. As described above, when an object touches the touch display panel 10, the capacitance of the touch electrode 33 at the touch position changes. However, the capacitance value of the touch electrode 33 is not necessarily changed by the object touch. The noise generated by the environment or the erroneous touch will also cause the capacitance value on the touch electrode 33 to change, but in this case, the change of the capacitance value is smaller. Therefore, a first threshold is set, the controller 35 determines whether the acquired first touch sensing signal is greater than the first threshold, and if so, the controller determines that the touch sensing signal is caused by object touch, and then performs a subsequent coordinate calculation step; if not, the touch control signal is considered as noise, and subsequent calculation is not carried out according to the first touch control induction signal.

Still further, a first coordinate is calculated according to the first touch sensing signal: establishing a plane coordinate system on a plane where the touch electrodes 33 are located, wherein each touch electrode 33 has a unique coordinate; the coordinates of the touch electrodes 33 are weighted and averaged according to the variation of the capacitance value of each touch electrode 33, and the calculated coordinates are defined as the first coordinates. The above-mentioned method for calculating the first coordinate according to the first touch sensing signal may adopt a conventional touch coordinate calculation method of a self-contained touch device.

Referring to fig. 5 (for clarity, parts of the elements are omitted in fig. 5, and the distances between the detection lines and the touch electrodes are exaggerated), the touch electrodes 33 are arranged in an array including rows and columns. The number of the touch electrodes 33 in each row is equal, and the number of the touch electrodes 33 in each column is equal. Each touch electrode 33 is represented by coordinates (X, Y). X represents a row coordinate and Y represents a column coordinate. In this example, (+ -x)₀，±y₀) The inner coordinates (coordinates within the smaller dashed box in fig. 5) are defined as non-edge coordinates, and the remaining coordinates are defined as edge coordinates.

In step S2, it is determined that the first coordinate is (± x)₀，±y₀) When the first coordinate is not the edge coordinate, judging that the first coordinate is not the edge coordinate; determining that the first coordinate is not (± x)₀，±y₀) And when the first coordinate is inside, judging that the first coordinate is an edge coordinate. x is the number of₀And y₀The specific value of (b) is preset and written in the judgment program of the controller 35.

As described above, when the touch position is at the edge position, the calculated touch coordinate is often deviated. Therefore, when the first coordinate is determined as the edge coordinate in step S2, it is necessary to further acquire the second touch sensing signals on the

detection lines

34R, 34G, and 34B in step S3 to correct the first coordinate. The detection lines 34R, 34G, and 34B are conductors (which may be metal or transparent conductive material) and may form an inductive capacitance with the touch object, where the inductive capacitance is the second touch sensing signal.

Setting a second threshold, in step S3, the controller 35 determines whether the acquired second touch sensing signal is greater than the second threshold, and if so, determines that the second touch sensing signal is caused by object touch, and performs a subsequent coordinate calculation step; if not, the second touch sensing signal on the detection line is considered as noise, and if not, the first coordinate is not corrected according to the second touch sensing signal, and the first coordinate is directly defined as a touch coordinate.

Further, the manner of correcting the first coordinate according to the second touch sensing signal is as follows: the correction parameter of the first coordinate is corrected according to the magnitude of the capacitance value variation on each

detection line

34R, 34G, and 34B.

In this embodiment, the touch display panel 10 includes three detection lines, and each detection line can respectively return a second touch sensing signal to the controller 35. The second touch sensing signal comprises capacitance variation on each detection line. According to the magnitude of the capacitance value variation on the three detection lines, which detection line the touch position is closer to can be deduced, so that the value of the correction parameter is determined. Each detection line corresponds to a value of a correction parameter. The product of the correction parameter and the first coordinate is the second coordinate.

For example, if it is determined that the capacitance variation in the detection line 34R is the largest in the

detection lines

34R, 34G, and 34B according to the second touch sensing signal, it can be estimated that the touch position is closer to the detection line 34R, the first coordinate is multiplied by the value of the correction parameter corresponding to the detection line 34R, and the calculated second coordinate is defined as the touch coordinate.

If the determination in step S2 is no, that is, the first coordinate is not an edge coordinate, the calculated first coordinate is considered to be relatively accurate, and the first coordinate is directly defined as the current touch coordinate without correcting the first coordinate.

Referring to fig. 6, in a comparative example, the touch display panel 50 has a plurality of touch electrodes 52 arranged in an array in a display area 51. At one time, the finger 60 touches the right edge (in the orientation shown in fig. 6). Although the area of the touch display panel 50 touched by the finger 60 is larger than the area of the one touch electrode 52, at this time, the finger 60 touches the right edge of the display area 51, a part of the area of the finger 60 touches the area corresponding to the touch electrode 520, and another part of the area touches the non-display area 53. Since there is no touch electrode in the non-display area 53, the touch of the finger 60 can only cause the capacitance change on the touch electrode 520 located in the display area 51, for example, the capacitance change on the touch electrode 520 is 90.

Referring to FIG. 7, at another time, the stylus 70 touches the right edge (based on the orientation shown in FIG. 7). The position where the stylus pen 70 touches the touch display panel 50 only causes a capacitance change on the touch electrode 520 located in the display area 51, for example, the capacitance change on the touch electrode 520 is 90.

As can be seen from the above description, the touch position of the finger 60 in fig. 6 is closer to the edge of the display area 51 than the touch position of the stylus 70 in fig. 7, that is, the touch position of the finger 60 in fig. 6 is different from the touch position of the stylus 70 in fig. 7, but the capacitance changes caused by the finger 60 and the stylus 70 are the same, so that when the touch object touches the edge, although the touch position is different, the capacitance changes caused by the finger 60 and the stylus 70 are the same, the calculated touch coordinates are also the same. Resulting in inaccurate touch coordinates at the edges.

The touch coordinate acquiring method provided by the present embodiment is applied to the touch display panel 10, and adds an extended touch sensing area on the basis of the initial touch sensing area, when a touch object (e.g., a finger, a stylus pen) touches the edge of the display area 31, it may cause a capacitance change on not only the touch electrode 22, but also the

detection lines

34R, 34G, and 34B in the extended touch sensing area, and the induced capacitance between the

detection lines

34R, 34G, and 34B and the touch object is used as the second touch sensing signal, when a touch object such as a finger touches the edge of the display area 31 (or the edge of the initial touch sensing area), the first coordinate obtained by calculation is corrected so as to be beneficial to obtaining more accurate touch coordinates, and the problem that the touch coordinates are not accurately calculated when the touch position is at the edge of the touch display panel is solved. In addition, the method and the device utilize the originally existing

detection lines

34R, 34G and 34B, and no new element is added, so that the manufacturing cost of the touch display panel 10 is well controlled on the basis of improving the accuracy of the touch coordinate.

In another embodiment, the touch display panel 10 is an on-cell (on-cell) touch display panel, and the touch electrodes 22 are disposed in the color film substrate 20. Specifically, the color filter substrate includes a color filter layer and a polarizer layer (not shown) stacked together, where the color filter layer is closer to the tft array substrate 30 than the polarizer layer, and the touch electrodes 22 are located between the color filter layer and the polarizer layer. In this embodiment, the touch electrodes 22 can still be disposed only in the display area 31, and the technical problem of inaccurate calculated touch coordinates exists at the edge of the display area 31. In this embodiment, the technical problem of inaccurate touch coordinates is solved by the same method as the in-cell touch display panel, and details are not repeated here.

It will be appreciated by those skilled in the art that the above embodiments are illustrative only and not intended to be limiting, and that suitable modifications and variations may be made to the above embodiments without departing from the true spirit and scope of the invention.

Claims

1. A touch display panel is defined with a display area and a non-display area, wherein the non-display area surrounds and is adjacent to the edge of the display area; wherein the touch display panel comprises:

the touch electrodes are arranged in the display area at intervals;

a plurality of detection lines located in the non-display area; and

2. The touch display panel of claim 1, wherein the detection lines surround the display area.

3. The touch display panel of claim 1, wherein the touch display panel is a self-contained touch display panel.

4. The touch display panel of claim 1, wherein the touch display panel is an in-cell touch display panel or an out-cell touch display panel.

5. The touch display panel of claim 1, wherein a plurality of sub-pixels are defined in the display area, each sub-pixel emitting light of one color;

the number of detection lines is the same as the number of colors of light emitted by the plurality of sub-pixels.

6. A touch coordinate acquisition method is applied to a touch display panel, wherein the touch display panel comprises a plurality of touch electrodes and a plurality of detection lines; the touch method is characterized by comprising the following steps:

acquiring first touch sensing signals on the touch electrodes, and calculating a first coordinate according to the first touch sensing signals;

judging whether the first coordinate is an edge coordinate;

if not, defining the first coordinate as a touch coordinate.

7. The method for acquiring touch coordinates according to claim 6, wherein the step of calculating the first coordinates according to the first touch sensing signal specifically comprises:

and judging whether the first touch sensing signal is larger than a first threshold value or not, and if so, calculating a first coordinate according to the first touch sensing signal.

8. The method for obtaining touch coordinates according to claim 6, wherein the step of correcting the first coordinates according to the second touch sensing signal to obtain second coordinates specifically comprises:

judging whether the second touch sensing signal is larger than a second threshold value or not;

if the first coordinate is judged to be the first coordinate, correcting the first coordinate according to the second touch sensing signal to obtain a second coordinate;

if not, defining the first coordinate as a touch coordinate.

9. The method for obtaining touch coordinates according to claim 6, wherein the step of correcting the first coordinates according to the second touch sensing signal to obtain second coordinates specifically comprises:

and determining a correction parameter for correcting the first coordinate according to the magnitude of the capacitance value variation on the detection lines.

10. The method as claimed in claim 9, wherein the touch display panel includes a plurality of detection lines, each detection line corresponding to a different correction parameter.

11. The method for acquiring touch coordinates according to claim 9, wherein the second coordinate is a product of the first coordinate and the correction parameter.

12. The touch coordinate acquisition method of claim 6, further comprising:

and outputting detection signals to the detection lines to detect the conductivity of the internal circuit of the touch display panel.