KR20170079524A - In-cell touch type liquid crystal display device - Google Patents

Abstract

The present invention has a problem of providing a scheme for compensating a common voltage by implementing a structure capable of feeding back a signal variation of a common voltage in an in-cell touch system.
To this end, according to the present invention, in a liquid crystal panel of an in-cell touch system, the data wiring and the non-display region are arranged so as to overlap each other to constitute a feedback wiring forming a capacitance.
Accordingly, it is possible to supply the compensation common voltage for canceling the common voltage ripple component to the touch block of the liquid crystal panel, thereby implementing a structure capable of feeding back the common voltage signal variation in the in-cell touch scheme, thereby compensating for the common voltage .

Description

[0001] The present invention relates to an in-cell touch type liquid crystal display (LCD)

The present invention relates to an in-cell touch-type liquid crystal display device, and more particularly, to an in-cell touch-type liquid crystal display device capable of compensating for a common voltage by implementing a structure capable of feeding back a signal variation of a common voltage in an in- .

2. Description of the Related Art [0002] As an information society develops, there has been a growing demand for display devices for displaying images. Recently, liquid crystal display devices (LCDs), plasma display panels (PDPs) Various flat display devices such as an organic light emitting diode (OLED) have been utilized.

Of these flat panel display devices, liquid crystal display devices are widely used because they have advantages of miniaturization, weight reduction, thinness, and low power driving.

In recent years, a touch function has been added to a liquid crystal display device due to the spread of a smart phone or a tablet. In particular, in order to reduce the size of a liquid crystal display device, in-cell touch method.

In a liquid crystal panel of such an in-line touch type liquid crystal display device, a touch block arranged in a matrix form in a display area is defined, a self-cap type touch electrode is arranged in a unit of a touch block, The corresponding sensing wiring is connected.

As described above, the touch electrodes constituted by touch block units are electrically insulated from each other, and a common voltage is applied to the display region through the corresponding sensing wiring.

As described above, in the liquid crystal panel of the in-cell touch method, the touch electrodes in the mutually insulated state are configured to receive the common voltage individually, and there is a structural limitation in implementing feedback on the common voltage signal in the liquid crystal panel .

This makes it impossible to compensate the ripple component even if ripple occurs in the common voltage due to the fluctuation of the data voltage. As a result, image quality deterioration such as horizontal crosstalk (C / T) and smear due to the common voltage ripple can be suppressed It can not be improved.

The present invention has a problem of providing a scheme for compensating a common voltage by implementing a structure capable of feeding back a signal variation of a common voltage in an in-cell touch system.

According to an aspect of the present invention, there is provided a liquid crystal display device including: a sensing wiring connected to a touch electrode formed in each of touch blocks disposed in a display region of a liquid crystal panel and transmitting a common voltage to a display region; And a compensating circuit for outputting a compensating common voltage in accordance with a feedback signal input from the feedback wiring, wherein the compensating circuit includes a data line extending to the non-display region, A touch-type liquid crystal display device is provided.

Here, the feedback wiring may have a state of being electrically insulated from the touch electrode in the liquid crystal panel.

The compensation circuit includes an operational amplifier having a capacitor receiving a feedback signal, a first resistor connected to the capacitor, an inverting input terminal connected to the first resistor, and a non-inverting input terminal receiving a reference common voltage, And a second resistor connected between the output terminal and the inverting input terminal.

The display device may further include a gate wiring intersecting with the data wiring and disposed in the same layer as the feedback wiring, and a pixel electrode disposed in the pixel region in the touch block, with the touch electrode and the insulating film interposed therebetween have.

In the present invention, in a liquid crystal panel of an in-cell touch system, a feedback wiring is formed so as to overlap in a data wiring and a non-display area to form a capacitance.

Accordingly, it is possible to supply the compensation common voltage for canceling the common voltage ripple component to the touch block of the liquid crystal panel, thereby implementing a structure capable of feeding back the common voltage signal variation in the in-cell touch scheme, thereby compensating for the common voltage .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view illustrating an in-cell touch-type liquid crystal display device according to an embodiment of the present invention; FIG.
2 is a diagram illustrating an example of a compensation circuit of a liquid crystal display device according to an embodiment of the present invention.
3 is a plan view showing a pixel region in a touch block of an array substrate of a liquid crystal panel according to an embodiment of the present invention.
4 is a cross-sectional view along line IV-IV in Fig. 3;
5 is a view schematically showing a non-display region portion where a data line and a feedback line overlap in an array substrate of a liquid crystal panel according to an embodiment of the present invention;
6 is a cross-sectional view taken along line VI-VI of Fig. 5;

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view illustrating an in-cell touch-type liquid crystal display according to an embodiment of the present invention.

Referring to FIG. 1, the liquid crystal display 100 according to the present embodiment may include a liquid crystal panel 110 for displaying an image and a driving circuit 200 for driving the liquid crystal panel 110.

The liquid crystal panel 110 is an in-cell touch type liquid crystal panel in which a touch electrode 171 serving as a self-cap type touch element is formed in the liquid crystal panel 110. Such a liquid crystal panel 110 may include, for example, a color filter substrate, a liquid crystal layer positioned between the array substrate and the color filter substrate as an opposing substrate facing the array substrate and the array substrate.

In this case, the touch electrode 171, that is, the common electrode 171 is formed on the array substrate together with the pixel electrode, and during the display period for displaying the image, Layer can be driven. The liquid crystal panel 110 having the touch electrode 171 may be formed by using, for example, an IPS (In-Plane Switching) method or an AH-IPS (Advanced High Performance In-Plane Switching) . In this embodiment, for the sake of convenience of description, a case will be exemplified in which an AH-IPS type liquid crystal panel 110 generating a fringe field is used.

In the liquid crystal panel 110, a display area AA for displaying an image and a non-display area NA around the display area AA are defined. For convenience of explanation, the upper, lower, left, and right portions of the non-display area NA with respect to the display area AA are referred to as first, second, third, and fourth non-display areas NA1, NA2, NA3, NA4).

In the display area AA, pixel regions (see P in Fig. 3) are arranged in a matrix form along the row direction and the column direction. Here, the pixel region is defined by a data line DL and a gate line (see GL in FIG. 3) intersecting with each other. The gate line is formed to cross the display region AA along the row direction in the first direction And the data line DL may be formed to cross the display area AA along the column direction which is the second direction. At this time, the data line DL may be configured such that one end extends into the first non-display area NA1 and the other end extends into the second non-display area NA2.

On the other hand, in the display area AA, a plurality of touch blocks TB may be arranged in a matrix form along the row direction and the column direction. At this time, each touch block TB is composed of a plurality of pixel regions neighboring in the row direction and the column direction as a unit group.

A touch electrode 171 is formed on an array substrate of the liquid crystal panel 110 in units of a touch block (TB). The touch electrode 171 formed on each touch block TB is patterned in a form separated from the touch electrode 171 of the neighboring touch block TB. That is, the touch electrodes 171 formed in the neighboring touch block TB are electrically disconnected from each other to be insulated.

A sensing wiring SL connected to each of the touch blocks TB is formed on the array substrate of the liquid crystal panel 110 along one direction. For example, the sensing wiring SL can be formed along the column direction which is the extending direction of the data line DL. The sensing wiring SL is connected to the touch electrode 171 of the corresponding touch block TB through the touch contact hole CH to transmit a driving signal.

In this regard, a common voltage is applied to the sensing wiring SL and transmitted to the corresponding touch electrode 171 during each frame as a display period. Accordingly, an electric field is generated between the pixel electrode and the touch electrode 171 in each pixel region of the corresponding touch block TB to drive the liquid crystal, thereby displaying an image.

On the other hand, a touch driving signal of a pulse waveform is applied to the sensing wiring SL and transmitted to the touch electrode 171 during a blank interval between neighboring frames as a touch sensing interval between display periods. In addition, a sensing signal corresponding to the amount of change in the touch capacitance of each touch block TB according to the touch is detected through the touch electrode 171 and applied to the corresponding sensing wiring SL. Thus, it is possible to determine whether or not the user touches the sensing signal.

The touch electrode 171 formed on the touch block TB functions as a common electrode 171 for generating an electric field and an electrode for sensing a user touch, . ≪ / RTI >

Particularly, according to this embodiment, the feedback wiring FL for feeding back the signal variation of the common voltage is formed in the non-display area NA.

As described above, the feedback line FL is formed in the non-display area NA, so that the feedback line FL is electrically insulated from the touch electrodes 171 disposed in the display area AA in the liquid crystal panel 110. [ Accordingly, a feedback structure can be effectively implemented in the in-cell touch method. To this end, the feedback wiring line FL is electrically connected to the data line DL (DL) through the insulating film in the non-display area NA And overlap each other.

In other words, in the first non-display area NA where one end of the data line DL extending along the column direction is located, the feedback line FL extends in the row direction along the side of the display area AA So as to overlap the entire data lines DL in the liquid crystal panel 110. Here, for convenience of explanation, the portion of the feedback wiring FL which intersects with the data line DL and is overlapped is referred to as a detection portion FL1.

As described above, the detecting portion FL1 overlaps the data line DL, so that a capacitance Cd is formed therebetween. As described above, the variation amount of the data voltage applied to the data line DL can be detected by the capacitance Cd generated between the detecting portion FL1 and the data line DL.

The variation of the data voltage corresponds to a factor of generating a ripple of a common voltage applied to the touch electrodes 171, i.e., the common electrodes 171 of the liquid crystal panel 110. Therefore, when the variation of the data voltage is detected, the ripple component of the common voltage in the liquid crystal panel 110 can be detected, and the common voltage compensation applied to the liquid crystal panel 110 through the feedback of the ripple component .

Thus, in this embodiment, the feedback wiring FL is overlapped with the data wiring DL so that the capacitance Cd is formed therebetween, so that the ripple component of the common voltage due to the data voltage fluctuation is transmitted through the feedback wiring FL So that it can be detected effectively.

The feedback wiring FL may include a transfer portion FL2 for transferring the feedback signal FS detected through the detection portion FL1 to the compensation circuit CC of the drive circuit portion 200. [

The transmission part FL2 extends from at least one end of the detection part FL1 and extends along at least one of the third and fourth non-display areas NA3 and NA4 so as to be electrically connected to the compensation circuit CC. Lt; / RTI > In this embodiment, for convenience of explanation, the case where the transmitting portion FL2 is connected to both ends of the detecting portion FL1 and is disposed in each of the third and fourth non-display areas NA3 and NA4 is shown as an example. On the other hand, when the driving circuit unit 200 is located on the second non-display area NA2 side and a signal output from the driving circuit unit 200 is input to the liquid crystal panel 110 through this part, Display area NA2 and is connected to the driving circuit unit 200. The driving circuit unit 200 is connected to the first non-display area NA2.

The driving circuit unit 200 for generating and outputting a driving signal for driving the liquid crystal panel 110 includes a compensation circuit CC for compensating for a common voltage, (TC). ≪ / RTI > Furthermore, although not specifically shown, the driving circuit portion 200 may include a data driving circuit for outputting a data voltage to the data line DL and a gate driving circuit for outputting a gate voltage to the gate wiring.

The compensation circuit CC receives the feedback signal FS, which is a signal detected from the feedback wiring FL, at the input terminal and outputs the compensation common voltage Vcomc, whose polarity is inverted on the basis of the reference common voltage Vref, at the output terminal do. That is, the compensation circuit CC outputs the common voltage of the form in which the ripple component of the feedback signal FS is inverted as the compensation common voltage Vcomc.

The compensating common voltage Vcomc is transmitted to the touch driving circuit TC and the touch driving circuit TC outputs the compensating common voltage Vcomc to each sensing wiring SL in the display period, To the respective touch blocks (TB)

Accordingly, when a common voltage ripple is generated in the liquid crystal panel 110, a compensation common voltage Vcomc having a waveform canceling the ripple component can be generated and applied to the inside of the liquid crystal panel 110. Thus, the common voltage ripple is removed by the compensation common voltage Vcomc, so that the image quality deterioration due to the common voltage ripple can be improved.

The compensation circuit CC for generating the compensation common voltage Vcomc as described above may be constructed using an operational amplifier OP as shown in FIG. 2, but the present invention is not limited thereto.

2, the compensation circuit CC includes a capacitor C receiving the feedback signal FS, and a capacitor C connected in series with the capacitor C. The compensation circuit CC includes a capacitor C, 1 operational amplifier OP whose first resistor R1 is connected to the inverting input terminal (-) and the reference common voltage Vref is input to the non-inverting input terminal (+), have. Furthermore, the compensation circuit CC may include a second resistor R2, which is a gain resistor connected between the output terminal of the operational amplifier OP and the inverting input terminal (-).

At this time, the amplification ratio of the operational amplifier OP is determined by the ratio (R2 / R1) of the first and second resistances R1 and R2, and the amplification ratio is adjusted to match the characteristics of the liquid crystal panel 110. [

The compensation circuit CC configured as described above inverts the feedback signal FS inputted through the capacitor C with reference to the reference common voltage Vref to output the compensation common voltage Vcomc.

Accordingly, when the ripple component is included in the feedback signal FS, the compensation common voltage Vcomc of the waveform in which the ripple component is inverted and amplified is generated and applied to the liquid crystal panel 110, The common voltage ripple can be canceled and removed.

Hereinafter, the structure of the array substrate of the liquid crystal panel 110 constructed as above will be described in more detail.

FIG. 3 is a plan view showing a pixel region in a touch block of an array substrate of a liquid crystal panel according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along a line IV-IV in FIG. 5 is a view schematically showing a non-display region portion where a data line and a feedback line are overlapped in an array substrate of a liquid crystal panel according to an embodiment of the present invention, and Fig. 6 is a cross- Fig.

First, the structure of the pixel region P in the touch block TB will be described with reference to FIGS. 3 and 4. FIG.

In the display area AA of the array substrate of the liquid crystal panel 110, a plurality of gate lines GL extending in the row direction are formed on the substrate 111 in the first direction. On the gate line GL, a plurality of data lines DL extending along the column direction, which is a second direction intersecting the first direction, with the gate insulating film 130 interposed therebetween is formed.

As described above, a plurality of pixel regions P arranged in a matrix form are defined by gate lines and data lines GL and DL crossing each other.

In each pixel region P, a thin film transistor T connected to a gate wiring and data lines GL and DL is formed.

The thin film transistor T includes a gate electrode 121 connected to the gate wiring GL, a semiconductor layer 131 located on the gate insulating film 130 on the gate electrode 121, And source and drain electrodes 141 and 143 spaced apart from each other. Here, the source electrode 141 is connected to the data line DL.

A pixel electrode 151 connected to the drain electrode 143 of the thin film transistor T is formed in each pixel region P. In this case, the pixel electrode 151 may be connected to the drain electrode 143 through the drain contact hole. In this case, the pixel electrode 151 may include a drain contact hole for exposing the drain electrode 143, .

The touch electrode 171 or the common electrode 171 is formed in units of touch blocks TB and includes at least one insulating layer such as first and second protective layers 161 and 162 on the pixel electrode 151 To form a fringe field. The common electrode 171 includes a plurality of electrode patterns 175 each having a bar shape facing the pixel electrode 151 corresponding to each pixel region P and an opening 176 May be formed.

Here, the plurality of electrode patterns 175 may be formed to extend along the extending direction of the data lines DL. The plurality of electrode patterns 175 includes a first electrode pattern 175a positioned nearest to the data line DL and located at the outermost side of the pixel region P and a second electrode pattern 175b located inside the first electrode pattern 175a And the second electrode pattern 175b.

Here, the first electrode pattern 175a may be formed to have a width wider than the data line DL and substantially obscure the lower data line DL, but the present invention is not limited thereto. The first electrode pattern 175a may have a width larger than that of the sensing line SL overlapping the data line DL so as to substantially cover the sensing line SL corresponding to the lower portion of the sensing line SL. But is not limited to.

When the first electrode pattern 175a is formed in this manner, the first electrode pattern 175a functions as a shielding electrode between the data line DL and the pixel electrode 151 to prevent electrical interference therebetween. Similarly, the first electrode pattern 175a functions as a shielding electrode between the sensing wiring line SL and the pixel electrode 151, thereby preventing electrical interference therebetween.

The second electrode pattern 175b may be formed to have a smaller width than the first electrode pattern 175a, but the present invention is not limited thereto.

As another example, a plate-shaped common electrode 171 may be formed on each of the touch blocks TB, and a common electrode 171 may be formed on the common electrode 171 A pixel electrode 151 composed of a plurality of electrode patterns can be formed with an insulating film interposed therebetween.

As another example, the common electrode 171 and the pixel electrode 151 may be formed so as to have an electrode pattern, and they may be disposed on the same layer or disposed with an insulating film interposed therebetween.

The common electrode 171 and the pixel electrode 151 are formed of a transparent conductive material such as ITO, IZO, or ITZO.

On the other hand, the sensing wiring SL may extend along the extending direction of the data line DL and be configured to overlap with the data line DL. If the sensing wiring SL is disposed so as to overlap with the data wiring DL as the non-display element, the opening ratio can be prevented from being lowered by the sensing wiring SL and the width of the sensing wiring SL can be maximized The resistance can be reduced. The sensing line SL and the data line DL may be disposed with at least one insulating layer, for example, the first protective layer 161 interposed therebetween.

The sensing wiring SL may be disposed between the common electrode 171 and an insulating film such as a second protective film 162. These electrodes may be formed in the touch contact hole CH formed in the second protective film 162, As shown in FIG.

Next, the structure of the non-display area NA where the data line DL and the feedback line FL are overlapped will be described with reference to FIGS. 5 and 6. FIG.

The feedback wiring FL for feeding back the signal variation of the common voltage is formed in the non-display area NA in the non-display area NA of the array substrate of the liquid crystal panel 110, that is, the first non-display area NA1. At this time, the feedback interconnection line FL may be formed in the same process as the gate interconnection line GL and may be located on the same layer with the same material, but the present invention is not limited thereto. At this time, the gate line GL is formed of a low-resistance material, and it is preferable that the feedback line FL is formed of the same material as the gate line GL in terms of signal transmission.

As described above, the feedback line FL is formed in the non-display area NA, so that the feedback line FL is electrically insulated from the touch electrodes 171 disposed in the display area AA in the liquid crystal panel 110. [ Accordingly, the feedback structure can be effectively implemented in the in-cell touch method. To this end, the feedback wiring FL is formed in the first non-display area NA, which is the non-display area NA, 130 overlap each other with the data line DL interposed therebetween.

That is, in the first non-display area NA1, the detection part FL1 of the feedback line FL extending in the row direction along the side of the display area AA substantially covers all of the data lines DL .

As described above, the detecting portion FL1 overlaps the data line DL, so that a capacitance Cd is formed therebetween. As described above, the variation amount of the data voltage applied to the data line DL can be detected by the capacitance Cd generated between the detecting portion FL1 and the data line DL.

The common voltage ripple applied to the liquid crystal panel 110 is generated by the data voltage variation. Accordingly, by detecting the variation amount of the data voltage, it is possible to detect the ripple component of the common voltage in the liquid crystal panel 110, and the common voltage applied to the liquid crystal panel 110 through the feedback of the ripple component Compensation becomes possible.

In this way, the feedback wiring FL is overlapped with the data wiring DL so that the capacitance Cd is formed therebetween, so that the ripple component of the common voltage due to the data voltage variation can be effectively detected through the feedback wiring FL .

On the other hand, the feedback line FL is provided with a transmission portion FL2 for transmitting the feedback signal FS detected through the detection portion FL1 to the compensation circuit (see CC in Fig. 1) of the drive circuit portion (see 200 in Fig. 1) .

The transmission part FL2 extends from at least one end of the detection part FL1 and extends along at least one of the third and fourth non-display areas NA3 and NA4 so as to be electrically connected to the compensation circuit CC. Lt; / RTI >

In this way, the feedback signal FS detected through the feedback wiring line FL is transmitted to the compensation circuit. In response to this, the compensation circuit compensates the compensated common voltage Vref by inverting the feedback signal FS based on the reference common voltage Vref Vcomc) is generated and output.

Accordingly, the compensation common voltage Vcomc is transmitted to the touch driving circuit (see TC in FIG. 1), applied to the sensing wiring SL, and transmitted to each touch block TB inside the liquid crystal panel 110.

Thus, the ripple component of the common voltage in the liquid crystal panel 110 is canceled by the compensated common voltage Vcomc, so that the deterioration of image quality due to the common voltage ripple can be improved.

As described above, according to the embodiment of the present invention, in the liquid crystal panel of the in-cell touch method, the data wiring and the non-display region are arranged so as to overlap each other to constitute the feedback wiring forming the capacitance.

Accordingly, it is possible to supply the compensation common voltage for canceling the common voltage ripple component to the touch block of the liquid crystal panel, thereby implementing a structure capable of feeding back the common voltage signal variation in the in-cell touch scheme, thereby compensating for the common voltage .

The embodiment of the present invention described above is an example of the present invention, and variations are possible within the spirit of the present invention. Accordingly, the invention includes modifications of the invention within the scope of the appended claims and equivalents thereof.

100: liquid crystal display device 110: liquid crystal panel
111: substrate 121: gate electrode
130: gate insulating film 131: semiconductor layer
141: source electrode 143: drain electrode
151: pixel electrode 161: first protective film
162: Second protective film
171: Touch electrode (common electrode)
175, 175a, 175b: electrode pattern, first electrode pattern, second electrode pattern
176: aperture 200: drive circuit part
GL: gate wiring
DL: Data wiring
T: thin film transistor
SL: sensing wiring
FL, FL1, FL2: feedback wiring, detection section,
Cd: capacitance
TB: a touch block, a first touch block, a second touch block
CH: Touch contact hole
AA, NA: display area, non-display area
P: pixel area
CC: compensation circuit
C: Capacitor
R1, R2: 1st and 2nd resistors
OP: Op Amp
TC: Touch driving circuit

Claims (4)

A touch electrode formed on each of the touch blocks disposed in the display region of the liquid crystal panel;
A sensing wiring connected to the touch electrode and transmitting a common voltage to the display section;
A data line extending to the non-display region across the display region;
A feedback wiring overlapping the data wiring with the insulating film interposed therebetween in the non-display region;
A compensation circuit for outputting a compensation common voltage according to a feedback signal input from the feedback wiring;
And a liquid crystal display panel.
The method according to claim 1,
Wherein the feedback wiring is electrically insulated from the touch electrode in the liquid crystal panel
Insel touch type liquid crystal display device.
The method according to claim 1,
Wherein the compensation circuit comprises:
A capacitor receiving the feedback signal;
A first resistor coupled to the capacitor;
An operational amplifier having an inverting input terminal to which the first resistor is connected and a non-inverting input terminal to which a reference common voltage is input;
And a second resistor connected between the output terminal of the operational amplifier and the inverting input terminal
Insel touch type liquid crystal display device.
The method according to claim 1,
A gate wiring crossing the data wiring and disposed in the same layer as the feedback wiring;
A plurality of pixel electrodes disposed in the pixel regions in the touch block,
The liquid crystal display device further comprising:

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