KR102242108B1 - Touch display device - Google Patents

Abstract

A touch display device capable of preventing a decrease in sensing sensitivity at an outer portion of a touch area is provided. The touch display device includes one or more dummy lines disposed between the outermost sensing line and the ground line.

Description

Touch display device

The present invention relates to a touch display device, and more particularly, to a touch display device capable of increasing touch sensing sensitivity by removing noise from an outermost sensing line in an in-cell type touch display device with a built-in touch panel.

Among various types of flat panel display devices, a liquid crystal display device is expanding its application field due to the merits of mass production technology, ease of driving means, high quality and large screen realization.

In recent years, as an input device of a liquid crystal display, a touch panel that allows a user to directly input information using a finger or a pen has been applied, replacing conventional input devices such as a mouse or keyboard.

In particular, in the case of a portable terminal such as a smartphone, when applying a touch panel to a liquid crystal display device, a touch panel-embedded liquid crystal display device in which a touch panel is built into the liquid crystal panel for slimming, that is, in-cell (In-cell) -Cell) type touch display device is being developed.

1 is a cross-sectional view illustrating a part of a conventional in-cell type touch display device, and FIG. 2 is a schematic plan view of FIG. 1.

1 and 2, a conventional in-cell type touch display device, that is, an in-cell touch display device 1 includes a lower substrate 10, an upper substrate 20, and a liquid crystal layer interposed between the two substrates ( 30).

A plurality of pixels P for detecting the presence or absence of a user's touch while driving the liquid crystal layer 30 are defined on the lower substrate 10. A pixel electrode 11 connected to a thin film transistor (not shown) is formed in each pixel P, and a common electrode 15 is formed on the pixel electrode 11 with an insulating layer 13 interposed therebetween. The pixel electrode 11 and the common electrode 15 are formed in the display area of the lower substrate 10, for example, the touch area TA. Here, the common electrode 15 is formed by being separated in block units within the touch area TA of the lower substrate 10.

On the upper substrate 20, a black matrix 21 is formed along the boundary of each pixel P of the lower substrate 10, and red, green, and blue colors are sequentially repeated in a region surrounded by the black matrix 21. A color filter 23 is formed. In addition, an overcoat layer 25 covering the black matrix 21 and the color filter 23 is formed.

In such a conventional in-cell touch display device 1, a common voltage Vcom is applied to the common electrode 15 during a display period in which an image is displayed, and in a non-display period in which an image is not displayed, the common electrode 15 is Used as an electrode for touch detection.

In other words, when the user touches the display area of the in-cell touch display device 1 with a finger, etc., the touch capacitance between the upper substrate 20 and the common electrode 15 or between the adjacent common electrode 15 Is formed. In this case, the touch control circuit 40 senses the touch capacitance through a plurality of touch wirings TL, and compares the sensed touch capacitance with the reference capacitance to detect the user's touch position.

Meanwhile, as shown in FIG. 2, in order to prevent electromagnetic interference (EMI) from being generated in the touch area TA by static electricity introduced from the outside, the conventional in-cell touch display device 1 The ground wiring GL is provided in an outer portion of TA), that is, in a non-display area surrounding the touch area TA.

However, in the conventional in-cell touch display device 1, the touch wiring TL formed at the outermost of the plurality of touch wirings TL is determined by the ground wiring GL surrounding the touch area TA. There is a problem that the sensing sensitivity to be sensed is deteriorated.

In other words, a parasitic capacitance is generated between the ground wiring GL and the outermost touch wiring TL adjacent thereto, and the parasitic capacitance increases as the ground wiring GL and the outermost touch wiring TL are adjacent. In addition, a capacitance variation is increased between the plurality of touch wiring lines TL due to the parasitic capacitance, and a noise component is increased by the capacitance variation. Sensing sensitivity of the outermost touch wiring TL is deteriorated by this noise component.

An object of the present invention is to provide a touch display device capable of increasing touch sensing sensitivity by removing noise from an outermost sensing line.

In order to achieve the above object, a touch display device according to an embodiment of the present invention includes a plurality of sensing lines provided in a touch area of a display panel, a ground line disposed adjacent to the outermost sensing line in a bezel area, and a sensing line and ground. It includes one or more dummy lines arranged between the lines.

In the touch display device according to the present invention, one or more dummy lines are added between the ground line surrounding the touch area and the outermost sensing line of the touch area, and the same signal as the sensing signal of the sensing line is supplied to the dummy line. As a result, it is possible to prevent parasitic capacitance and noise components from being generated in the outermost sensing line. Accordingly, it is possible to prevent a decrease in sensing sensitivity in the outer portion of the touch display device.

In addition, the touch display device of the present invention can reduce the distance between the outermost sensing line and the ground line by the dummy line, thereby reducing the width of the bezel area compared to the conventional touch display device.

1 is a cross-sectional view showing a part of a conventional in-cell type touch display device.
FIG. 2 is a schematic plan view of FIG. 1.
3 is a diagram illustrating an in-cell touch display device according to an exemplary embodiment of the present invention.
4 is a diagram illustrating in detail a connection between the display panel and the touch control unit shown in FIG. 3.
5A and 5B are diagrams showing cross-sections of a touch display device of the prior art and the present invention in area A of FIG. 4.
6A and 6B are cross-sectional views illustrating other embodiments of portion A of FIG. 4.
7 is a diagram illustrating signal waveforms of a sensing line and a dummy line of FIG. 4.

Hereinafter, a touch display device according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a diagram illustrating an in-cell touch display device according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the in-cell touch display device 100 of the present embodiment may include a display panel 110 in which a touch panel is embedded and a driving circuit unit for driving the same.

The display panel 110 may be a liquid crystal panel composed of a lower substrate (not shown), an upper substrate (not shown), and a liquid crystal layer (not shown) interposed between the two substrates. However, the present invention is not limited thereto, and the display panel 110 may be an organic light-emitting panel composed of an organic light-emitting diode.

The display panel 110 may include a touch area T/A and a bezel area B/A surrounding the touch area T/A. The touch area T/A may be a display area in which an image is displayed, and the bezel area B/A may be a non-display area in which no image is displayed. A plurality of pixels P may be arranged in a matrix form in the touch area T/A.

The plurality of pixels P may be formed on the lower substrate of the display panel 110. A thin film transistor (not shown) and a pixel electrode (not shown) may be formed in each of the plurality of pixels P. The thin film transistor may be connected to a gate line (not shown) and a data line (not shown).

A color filter (not shown) and a black matrix (not shown) corresponding to each pixel P of the lower substrate may be formed on the upper substrate of the display panel 110.

Meanwhile, when the display panel 110 is operated in a horizontal electric field mode, a common electrode (not shown) may be formed on the lower substrate. Also, when the display panel 110 is operated in the vertical electric field mode, the common electrode may be formed on the upper substrate.

The pixel electrode and the common electrode of the display panel 110 may be used as a touch electrode for detecting a user's touch position in addition to displaying an image in the touch area T/A. For example, one frame operation period of the display panel 110 may be divided into a display period and a non-display period, and a pixel voltage and a common voltage may be respectively applied to the pixel electrode and the common electrode during the display period. In the non-display period, a driving signal for detecting a touch may be supplied to the common electrode, and a change in capacitance formed between the pixel electrode and the common electrode may be sensed by a user's touch to detect the presence or absence of a touch.

To this end, the common electrode may be formed for each pixel P of the lower substrate, or may be formed by being blocked in units of a predetermined number of pixels. In addition, such a common electrode may be connected to a predetermined line, for example, a driving line (not shown) or a sensing line (not shown).

The driving circuit unit may include a timing control unit 140, a gate driving unit 120, a data driving unit 130, and a touch control unit 150. The driving circuit unit may be configured on a separate circuit board (not shown) and connected to the display panel 110 through a connection member, for example, a flexible printed circuit board (FPCB, not shown). In addition, some or all of the driving circuit units may be formed on the display panel 110.

The timing control unit 140 may convert the image signals R, G, and B into image data RGB using a timing signal such as a vertical synchronization signal, a horizontal synchronization signal, and a clock signal input from an external source. have. The image data RGB may be arranged in a frame unit and output to the data driver 130.

In addition, the timing control unit 140 may generate a gate control signal GCS, a data control signal DCS, and a touch control signal TCS according to a timing signal input from the outside. The gate control signal GCS may include a gate start pulse GSP, a gate shift clock GSC, a gate output enable GOE, and the like, and may be output to the gate driver 120. The data control signal DCS may include a source start pulse (SSP), a source sampling clock (SSC), a source output enable (SOE), a polarity control signal (POL), etc., and may be output to the data driver 130. I can. The touch control signal TCS may be output to the touch control unit 150.

The gate driver 120 may generate a plurality of gate signals according to the gate control signal GCS. The plurality of gate signals are sequentially output to the plurality of gate lines of the display panel 110 to operate the thin film transistors of each pixel P.

The data driver 130 may convert the image data RGB into a data voltage according to the data control signal DCS. The data voltage may be output to a plurality of data lines of the display panel 110 when the thin film transistor of each pixel P is turned on by the gate signal.

The touch control unit 150 may output a touch sensing signal for detecting a user's touch to a plurality of touch electrodes of the display panel 110 according to the touch control signal TCS. Here, as the touch electrode, a common electrode formed on the display panel 110 may be used as described above.

When the common electrode is used as a touch electrode, a common voltage Vcom for displaying an image may be applied to the common electrode during the display period of one frame period of the display panel 110. Thereafter, in the non-display period, a touch sensing signal for detecting a touch is applied to the common electrode, so that the common electrode may be driven as the touch electrode. In addition, the touch controller 150 may detect the presence or absence of a user's touch and a touch position by comparing the capacitance formed on the touch electrode with the reference capacitance. The presence or absence of a user's touch and a touch position may be performed during a blank signal period for dividing the previous frame and the next frame of the display panel 110.

4 is a diagram illustrating in detail a connection between the display panel and the touch control unit shown in FIG. 3.

3 and 4, a plurality of touch electrodes S1 and S2 formed by a plurality of common electrodes may constitute a touch area T/A on the display panel 110. The touch electrodes S1 and S2 may include a plurality of first touch electrodes S1 and a plurality of second touch electrodes S2.

The plurality of first touch electrodes S1 may be arranged in a first direction on the display panel 110 to constitute a plurality of driving channels Tx1 to Txn. Each of the plurality of first touch electrodes S1 arranged in the first direction may be connected to each other through the bridge electrode BE.

The plurality of second touch electrodes S2 may be arranged in the second direction on the display panel 110 to constitute a plurality of sensing channels Rx1 to Rxm. The plurality of sensing channels Rx1 to Rxm arranged in the second direction may be connected to each other through a plurality of sensing lines RL overlapping with the sensing channels Rx1 to Rxm.

Each of the plurality of first and second touch electrodes S1 and S2 may be formed in a rhombus shape, but may be formed in various shapes such as a triangle, a square, a polygon, and a circle.

A bezel region B/A of the display panel 110, that is, a bezel region B/A surrounding the touch region T/A, includes a plurality of driving channels Tx1 to Txn of the touch region T/A. And a plurality of wires connecting the plurality of sensing channels Rx1 to Rxm with the touch control unit 150 may be formed.

In other words, a plurality of driving lines (not shown) extending from each of the plurality of driving channels Tx1 to Txn of the touch area T/A to the touch control unit 150 may be formed in the bezel area B/A. have. In addition, a plurality of sensing lines RL extending from each of the plurality of sensing channels Rx1 to Rxm of the touch region T/A to the touch control unit 150 may be formed in the bezel region B/A.

As described above, the plurality of driving lines and the plurality of sensing lines RL may extend to the touch control unit 150 through a connection member, that is, a flexible printed circuit board. The plurality of driving lines supply driving signals applied from the touch control unit 150 to the plurality of driving channels Tx1 to Txn of the display panel 110, and the plurality of sensing lines RL are A sensing signal applied from the sensing channels Rx1 to Rxm of may be supplied to the touch controller 150.

In addition, a ground line GRL for blocking static electricity introduced from the outside may be formed in the bezel area B/A. The ground line GRL may be formed in the form of a closed loop or an open loop surrounding the touch area T/A. The ground line GRL may extend to the touch control unit 150 together with a plurality of driving lines and sensing lines RL, and may be connected to the ground GND of the touch control unit 150.

Meanwhile, the outermost sensing line RL overlapping the outermost sensing channels Rx1 and Rxm of the touch area T/A may be adjacent to the ground line GRL. At this time, parasitic capacitance due to a voltage difference may be generated between the outermost sensing line RL and the ground line GRL. This parasitic capacitance changes the size of the sensing signal of the outermost sensing line RL, and thus touch sensing sensitivity of the outermost sensing channels Rx1 and Rxm is deteriorated.

Accordingly, in the display panel 110 of the present exemplary embodiment, a dummy line DRL may be provided between the outermost sensing line RL and the ground line GRL. The dummy line DRL may be formed in the bezel area B/A of the display panel 110 and may be formed parallel to the ground line GRL or the outermost sensing line RL.

One or more dummy lines DRL may be formed between the outermost sensing line RL and the ground line GRL, and may be formed to have the same width as the outermost sensing line RL, or the outermost sensing line RL It can be formed in a larger width.

In addition, the dummy line DRL may extend to the touch control unit 150 together with the outermost sensing line RL, and a predetermined signal from the touch control unit 150, for example, a sensing signal of the outermost sensing line RL and Signals of the same size can be applied.

In other words, at least one dummy line DRL is formed between the outermost sensing line RL and the ground line GRL, and a signal having the same size as the sensing signal of the outermost sensing line RL on the dummy line DRL Can be applied. Accordingly, a parasitic capacitance is generated between the dummy line DRL and the ground line GRL, and the magnitude of the signal applied to the dummy line DRL is reduced by the parasitic capacitance.

For example, as shown in FIG. 7, when the sensing signal of the outermost sensing line RL is the first level (ΔV1), the signal of the dummy line DRL is smaller than the first level (ΔV1). It may be a second level (ΔV2) having. Here, the first level ΔV1 may be approximately 1.6 to 1.7V, and the second level ΔV2 may be approximately 0.6 to 0.7V.

That is, the display panel 110 of the present exemplary embodiment comprises at least one dummy line DRL between the outermost sensing line RL and the ground line GRL, and between the dummy line DRL and the ground line GRL. By allowing the parasitic capacitance to be generated, it is possible to prevent the parasitic capacitance from being generated in the outermost sensing line RL by the ground line GRL. Accordingly, the touch display device 100 of the present invention can prevent a decrease in the sensing sensitivity of the outermost part of the touch area T/A of the display panel 110, that is, the outermost sensing channels Rx1 and Rxm. have.

The touch control unit 150 sequentially supplies driving signals to a plurality of driving channels Tx1 to Txn of the touch area T/A through a plurality of driving lines, and a first touch electrode S1 and a second touch electrode When the touch capacitance formed by the horizontal electric field (S2) changes, it may be sensed.

To this end, the touch control unit 150 compares the sensing signals output through the sensing line RL from two adjacent sensing channels Rx1 to Rxm among the plurality of sensing channels Rx1 to Rxm, and compares the sensing data SD1 to Rxm. SDm) may include a comparison unit 151 outputting. The comparison unit 151 may compare changes in capacitance of the sensing signals output from the two sensing channels Rx1 to Rxm, and then generate and output sensing data SD1 to SDm according thereto. The sensing data SD1 to SDm may include the presence or absence of a user's touch and a location, and may be output to the timing control unit 140.

In addition, the touch control unit 150 may further include one or more buffers 155 for buffering the sensing signal of the outermost sensing line RL and applying it to the dummy line DRL. A signal output from the buffer 155 to the dummy line DRL may have a size smaller than the original sensing signal due to a parasitic capacitance between the dummy line DRL and the ground line GRL.

5A and 5B are diagrams showing cross-sections of a touch display device of the prior art and the present invention in area A of FIG. 4.

Referring to FIG. 5A, in a conventional touch display device, a plurality of sensing lines RL1 and RL2 of a touch area T/A are spaced apart by a first interval d1. However, between the outermost sensing line RL1 and the ground line GRL among the plurality of sensing lines RL1 and RL2, the second interval d2 is greater than the first interval d1 in order to prevent the occurrence of parasitic capacitance. Spaced apart. Accordingly, in the conventional touch display device, the area of the bezel area B/A is increased by the second distance d2 between the outermost sensing line RL1 and the ground line GRL.

Referring to FIG. 5B, in the touch display device 100 of the present invention, a plurality of sensing lines RL1 and RL2 of the touch area T/A are spaced apart by a first interval d1. In addition, one or more dummy lines DRL may be disposed between the outermost sensing line RL1 and the ground line GRL among the plurality of sensing lines RL1 and RL2. In this case, the dummy line DRL may be spaced apart from the outermost sensing line RL1 by a first interval d1, and may be spaced apart from the ground line GRL by a first interval d1.

Accordingly, the outermost sensing line RL1 and the ground line GRL may be spaced apart by a third interval d3 having a size smaller than the second interval d2 of the conventional touch display device. The area of the bezel area B/A of the touch display device 100 may be reduced compared to a conventional touch display device.

Here, the first interval d1 may be approximately 30 μm, and the second interval d2 may be approximately 700 μm. In addition, the third interval d3 may be 100 μm or less.

6A and 6B are cross-sectional views illustrating other embodiments of portion A of FIG. 4.

Referring to FIG. 6A, a plurality of dummy is formed between a plurality of sensing lines RL1 and RL2 formed in the touch area T/A of the display panel 110 and a ground line GRL formed in the bezel area B/A. Lines, for example, a first dummy line DRL1 and a second dummy line DRL2 may be formed.

The first dummy line DRL1 and the second dummy line DRL2 may be disposed at the same interval as the plurality of sensing lines RL1 and RL2. In other words, the first dummy line DRL1 may be spaced apart from the outermost sensing line RL1 and the second dummy line DRL2 by a first interval, respectively. Further, the second dummy line DRL2 may be spaced apart from the first dummy line DRL1 and the ground line GRL by a first interval, respectively.

A signal having the same magnitude as the sensing signal of the outermost sensing line RL1 may be applied to the first dummy line DRL1 and the second dummy line DRL2, respectively. In this case, in the second dummy line DRL2 closest to the ground line GRL, the magnitude of the applied signal may be reduced due to the parasitic capacitance with the ground line GRL. In addition, in the first dummy line DRL1 adjacent to the second dummy line DRL2, the magnitude of the applied signal may be reduced due to the parasitic capacitance with the second dummy line DRL2.

Here, the signal of the first dummy line DRL1 may be reduced to a size smaller than that of the second dummy line DRL2. Accordingly, generation of parasitic capacitance between the first dummy line DRL1 and the outermost sensing line RL1 can be prevented.

That is, in the display panel 110 of the present embodiment, by forming a plurality of dummy lines DRL1 and DRL2 between the plurality of sensing lines RL1 and RL2 and the ground line GRL, The size of the parasitic capacitance can be reduced to a minimum, and accordingly, it is possible to prevent the size of the sensing signal from being changed by the parasitic capacitance in the outermost sensing line RL1.

Referring to FIG. 6B, one dummy is formed between the plurality of sensing lines RL1 and RL2 formed in the touch area T/A of the display panel 110 and the ground line GRL formed in the bezel area B/A. A line DRL may be formed. The dummy line DRL may be spaced apart from the outermost sensing line RL1 and the ground line GRL by a first interval, respectively.

Here, the dummy line DRL may be formed to have a larger width than the sensing lines RL1 and RL2. For example, the dummy line DRL may be formed to have substantially the same width as the ground line GRL. Further, a signal having the same size as the sensing signal of the outermost sensing line RL1 may be applied to the dummy line DRL.

As described above, in the display panel 110 of the present embodiment, one dummy line DRL is formed between the plurality of sensing lines RL1 and RL2 and the ground line GRL, but the width of the dummy line DRL is increased. By forming, it is possible to reduce the size of the parasitic capacitance generated by the ground line GRL. Accordingly, it is possible to prevent the size of the sensing signal from changing due to the parasitic capacitance in the outermost sensing line RL1.

As described above, the touch display device 100 of the present invention includes a plurality of sensing lines RL1 and RL2 formed in the touch area T/A of the display panel 110 and the ground formed in the bezel area B/A. By forming one or more dummy lines DRL between the lines GRL, it is possible to prevent parasitic capacitance from being generated in the outermost sensing line RL1 by the ground line GRL. Accordingly, it is possible to prevent a decrease in sensing sensitivity due to a change in the size of the sensing signal at the outer portion of the touch area T/A of the display panel 110.

Although many items are specifically described in the above description, this should be construed as an example of a preferred embodiment rather than limiting the scope of the invention. Therefore, the invention should not be determined by the described embodiments, but should be determined by the claims and equivalents to the claims.

100: touch display device 110: display panel
120: gate driving unit 130: data driving unit
140: timing control unit 150: touch control unit
GRL: Ground line DRL: Dummy line

Claims (8)

A plurality of sensing lines provided in the touch area of the display panel;
A ground line disposed adjacent to an outermost sensing line among the plurality of sensing lines in a bezel region of the display panel; And
At least one dummy line disposed between the outermost sensing line and the ground line in the bezel area,
The dummy line has a larger width than the outermost sensing line. The method of claim 1,
The dummy line is disposed in parallel with the outermost sensing line. The method of claim 1,
The dummy line is spaced apart from the outermost sensing line and the ground line at equal intervals, respectively. delete The method of claim 1,
The touch display device to which the same signal as the sensing signal of the outermost sensing line is applied to the dummy line. The method of claim 1,
Further comprising a touch control unit connected to the display panel to drive the touch area,
The ground line extends from the display panel to the touch control unit and is connected to the ground. The method of claim 6,
The touch control unit,
A comparison unit for generating sensing data by comparing sensing signals of two adjacent sensing lines among the plurality of sensing lines; And
A touch display device comprising a buffer for buffering a sensing signal of the outermost sensing line and outputting the buffered signal to the dummy line. A plurality of sensing lines provided in the touch area of the display panel;
A ground line disposed adjacent to an outermost sensing line among the plurality of sensing lines in a bezel region of the display panel; And
A first dummy line and a second dummy line disposed between the outermost sensing line and the ground line in the bezel region,
The first dummy line is spaced apart from the outermost sensing line and the second dummy line at a first interval, and the second dummy line is spaced apart from the first dummy line and the ground line at the first interval, respectively. Touch display device.

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