KR101481660B1 - Liquid Crystal Display Device And Method For Driving Thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device capable of enhancing the reliability of a touch sensor circuit and a driving method thereof.

The liquid crystal display device includes a plurality of pixels defined as an intersection of gate lines and data lines; A plurality of touch sensor circuits driven by driving voltages to sense external light and generate a light sensing signal; A first high potential driving voltage supply line connected in common to the odd numbered pixel rows to supply a high potential driving voltage to the touch sensor circuits formed on the odd numbered pixel rows; A second high potential driving voltage supply line commonly connected to the excellent pixel rows to supply the high potential driving voltage to the touch sensor circuits formed on the excellent pixel rows; And intermittently applying the high potential driving voltage to each of the first and second high potential driving voltage supply lines and alternately applying the high potential driving voltage to the first and second high potential driving voltage supply lines And a driving voltage supply unit.

Description

[0001] The present invention relates to a liquid crystal display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a liquid crystal display device incorporating a touch sensor circuit, and more particularly, to a liquid crystal display device and a driving method thereof that can improve the reliability of a touch sensor circuit.

The liquid crystal display displays an image by controlling the light transmittance of the liquid crystal layer through an electric field applied to the liquid crystal layer in accordance with a video signal. Such a liquid crystal display device is a flat panel display device having advantages of small size, thinness and low power consumption, and is used as a portable computer such as a notebook PC, office automation equipment, audio / video equipment and the like. A liquid crystal display device having such a configuration is rapidly replacing a cathode ray tube (CRT) because of its thinness and low power consumption.

Particularly, an active matrix type liquid crystal display device in which a switching element is formed for each liquid crystal cell is capable of actively controlling a switching element, which is advantageous for a moving image.

A thin film transistor (hereinafter referred to as "TFT") is mainly used as a switching element used in such an active matrix type liquid crystal display device as shown in Fig.

1, an active matrix type liquid crystal display device converts digital input data into an analog data voltage on the basis of a gamma reference voltage and supplies the analog data voltage to a data line DL and simultaneously supplies a scan pulse to a gate line GL Thereby filling the liquid crystal cell Clc. To this end, the gate electrode of the TFT is connected to the gate line GL, the source electrode thereof is connected to the data line DL, and the drain electrode of the TFT is connected to the pixel electrode of the liquid crystal cell Clc and the storage capacitor Cst1 And is connected to one electrode. A common voltage Vcom is supplied to the common electrode of the liquid crystal cell Clc. The storage capacitor Cst1 functions to charge the data voltage applied from the data line DL when the TFT is turned on to maintain the voltage of the liquid crystal cell Clc constant. When a scan pulse is applied to the gate line GL, the TFT is turned on to form a channel between the source electrode and the drain electrode to apply a voltage on the data line DL to the pixel electrode of the liquid crystal cell Clc Supply. At this time, the liquid crystal molecules of the liquid crystal cell Clc are changed in arrangement by the electric field between the pixel electrode and the common electrode to modulate the incident light.

Such a liquid crystal display device is a passive light emitting device and adjusts the brightness of the screen by using a backlight unit disposed on the back surface of the liquid crystal display panel.

On the other hand, a touch screen panel (touch screen panel) is generally mounted on a display device, and is a user interface for sensing the touch point of a touch point that touches a hand or a pen. . A liquid crystal display device with a touch screen panel can find out whether a user's finger, touch pen, or the like has come into contact with a screen and contact position information, and can implement various applications using the detected information have.

However, such a liquid crystal display device causes problems such as a cost increase due to a touch screen panel, a reduction in yield due to a process of adhering a touch screen panel on a liquid crystal display panel, a decrease in luminance of a liquid crystal display panel, and an increase in thickness.

In order to solve the problems described above, a technique has been recently developed in which a touch sensor circuit including a sensor TFT as shown in Fig. 2 is formed inside a liquid crystal cell Clc of a liquid crystal display instead of a touch screen panel. The touch sensor circuit includes a sensor TFT that generates a photocurrent i differently according to a change in the quantity of light incident from the outside, a storage capacitor Cst2 that stores charges by the photocurrent i, and a charge storage capacitor Cst2 that is stored in the storage capacitor Cst2. And a switch TFT for outputting the light detection signal to the outside. Here, a low potential bias voltage Vbias set at a voltage equal to or lower than the threshold voltage of the sensor TFT is supplied to the gate electrode of the sensor TFT. The liquid crystal display device can determine the contact state and / or the contact position information of the user's finger based on the light sensing signal of the touch sensor circuit.

However, since the sensor TFT must always be supplied with the direct-current driving voltage Vdrv at a high potential through its drain electrode for such light sensing operation, it is easily deteriorated during long-term driving. When the sensor TFT deteriorates, a large error may occur in the output detection signal because the output characteristic of the touch sensor circuit changes. In other words, the touch sensor circuit may output a non-contact sensing signal even if a user's finger touches the liquid crystal cell formed with the touch sensor circuit. In contrast, even if the user's finger or the like does not touch the liquid crystal cell, May be output.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a liquid crystal display device and a method of driving the same that can enhance the reliability of a touch sensor circuit.

According to an aspect of the present invention, there is provided a liquid crystal display comprising: a plurality of pixels defined as intersections of gate lines and data lines; A plurality of touch sensor circuits driven by driving voltages to sense external light and generate a light sensing signal; A first high potential driving voltage supply line connected in common to the odd numbered pixel rows to supply a high potential driving voltage to the touch sensor circuits formed on the odd numbered pixel rows; A second high potential driving voltage supply line commonly connected to the excellent pixel rows to supply the high potential driving voltage to the touch sensor circuits formed on the excellent pixel rows; And intermittently applying the high potential driving voltage to each of the first and second high potential driving voltage supply lines and alternately applying the high potential driving voltage to the first and second high potential driving voltage supply lines And a driving voltage supply unit.

The period in which the high potential driving voltage is intermittently applied is a vertical period.

The driving voltage supply unit commonly supplies a low potential driving voltage to touch sensor circuits formed on the odd and even pixel rows through a low potential driving voltage supply line commonly connected to the odd and even pixel rows.

The liquid crystal display device according to an embodiment of the present invention further includes a plurality of lead-out lines for outputting the light sensing signal.

The touch sensor circuit includes a gate electrode connected to the low potential driving voltage supply line, a source electrode connected to one of the first and second high potential driving voltage supply lines, and a drain electrode connected to the first node, A sensor TFT having a source-drain channel current flowing by the external light when the high-potential driving voltage is applied; A storage capacitor connected between the low potential driving voltage supply line and the first node and storing charges due to the channel current; And a switching TFT for outputting the accumulated charge as one of the lead-out lines as the photo-sensing signal.

The liquid crystal display device according to an embodiment of the present invention further includes a lead-out integration unit connected to the lead-out lines, for amplifying the photo-sensing signal from the lead-out lines and outputting the amplified voltage.

The touch sensor circuit is formed at intervals of a length larger than the pixels.

According to another aspect of the present invention, there is provided a liquid crystal display comprising: a plurality of pixels defined as intersections of gate lines and data lines; A plurality of touch sensor circuits for sensing external light using high potential driving voltages supplied to the first and second sensor TFTs formed in a part of the pixels and connected in parallel; A first high potential driving voltage supply line for supplying a high potential driving voltage to the first sensor TFT; A second high-potential driving voltage supply line for supplying the high-potential driving voltage to the second sensor TFT; And intermittently applying the high potential driving voltage to each of the first and second high potential driving voltage supply lines and alternately applying the high potential driving voltage to the first and second high potential driving voltage supply lines And a driving voltage supply unit.

A plurality of pixels defined by the intersection of the gate lines and the data lines according to an embodiment of the present invention, a liquid crystal driving circuit having a plurality of touch sensor circuits driven by driving voltages to generate external light, A method of driving a display device includes: supplying a high potential driving voltage to touch sensor circuits formed on the odd number pixel rows through a first high potential driving voltage supply line commonly connected to odd numbered pixel rows; And supplying the high potential driving voltage to the touch sensor circuits formed on the fine pixel rows through a second high potential driving voltage supply line commonly connected to the fine pixel lines; The high potential driving voltage is intermittently applied to each of the first and second high potential driving voltage supply lines and alternately applied to the first and second high potential driving voltage supply lines.

According to another embodiment of the present invention, there is provided a liquid crystal display device comprising a plurality of pixels defined by intersections of gate lines and data lines, a plurality of pixels arranged in a part of the pixels and supplied with first and second sensor TFTs connected in parallel, A method of driving a liquid crystal display having a plurality of touch sensor circuits for sensing external light using voltages includes supplying a high potential driving voltage to the first sensor TFT through a first high potential driving voltage supply line; And supplying the high potential driving voltage to the second sensor TFT through a second high potential driving voltage supply line; The high potential driving voltage is intermittently applied to each of the first and second high potential driving voltage supply lines and alternately applied to the first and second high potential driving voltage supply lines.

The liquid crystal display device and the driving method thereof according to the present invention can intermittently apply a high potential driving voltage supplied to the touch sensor circuit to prevent deterioration of the touch sensor circuit, thereby preventing erroneous operation of the touch sensor circuit and improving reliability.

Other objects and advantages of the present invention will become apparent from the following description of preferred embodiments of the present invention with reference to the accompanying drawings.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 3 to 10. FIG.

3 is a block diagram showing a liquid crystal display device according to the present invention.

3, the liquid crystal display according to the present invention includes a plurality of gate lines G0 to Gn, a plurality of data lines D1 to Dm, and a plurality of driving voltage supply lines VL1 to VLn, A liquid crystal display panel 40 in which pixels 42 having a touch sensor circuit are arranged at intersections thereof, a data driver 20 for supplying a data voltage to the data lines D1 to Dm, A gate driver 30 for supplying a scan pulse to the scan electrodes G1 to Gn, a timing controller 10 for controlling the driving timing of the data driver 20 and the gate driver 30, VL1 to VLn to drive the touch sensor circuit in the pixel 42 and the read out lines ROL1 to RLOm of the liquid crystal display panel 152, A lead-out integration section 60 connected in common to the back surface of the liquid crystal display panel 40, And a backlight unit 70 for irradiating.

The liquid crystal display panel 40 includes an upper substrate including a color filter, a lower substrate on which pixels 42 including a pixel circuit and a touch sensor circuit are formed, and a liquid crystal layer interposed between the upper substrate and the lower substrate do.

A plurality of data lines D1 to Dm and a plurality of gate lines G1 to Gn are orthogonal to one another and a plurality of gate lines G1 to Gn parallel to the gate lines G1 to Gn are formed on a lower substrate of the liquid crystal display panel 40. [ A plurality of lead-out lines ROL1 to ROLm are formed which are orthogonal to the driving voltage supply lines VL1 to VLn, the gate lines G1 to Gn and the driving voltage supply lines VL1 to VLn. The pixel circuit P1 as shown in FIG. 4 is formed at the intersection of the data lines D1 to Dm and the gate lines G1 to Gn and the driving voltage supply lines VL1 to VLn and the lead- ROL1 to ROLm) are formed at the intersections of the touch sensor circuits P2 as shown in Fig. Each of the drive voltage supply lines VL1 to VLn includes high potential drive voltage supply lines VL1a to VLna for supplying a high potential drive voltage to the touch sensor circuit P2, And low-potential driving voltage supply lines (VL1b to VLnb) for supplying a driving voltage. The touch sensor circuit P2 detects a change in external light input thereto and generates a light sensing signal and supplies the light sensing signal to the lead-out integration unit 60 through the lead-out lines ROL1 to ROLm . On the other hand, the touch sensor circuit P2 may be arranged for each pixel 42, but it may be formed at a larger interval than the pixel for improving the aperture ratio.

On the upper substrate of the liquid crystal display panel 40, a black matrix is formed to cover the color filters and the pixel boundary. A common electrode to which a common voltage is supplied in opposition to the pixel electrode with the liquid crystal layer interposed therebetween is formed on the upper substrate in a TN (Twisted Nematc) mode or a VA mode (Vertical Alignment) mode, (Fringe Field Switching) mode or the like.

Further, polarizers for selecting linearly polarized light and alignment films for determining the pretilt of liquid crystal molecules are formed on the upper and lower substrates of the liquid crystal display panel 40, respectively.

The data driver 20 supplies the digital video data R, G and B to the gamma reference voltages GMA (not shown) from the gamma reference voltage generator (not shown) in response to the data control signal DDC from the timing controller 10. [ , And supplies the analog gamma compensation voltage to the data lines D1 to Dm of the liquid crystal display panel 40 as a data voltage.

The gate driver 30 generates a scan pulse in response to the gate control signal GDC from the timing controller 10 and sequentially supplies the scan pulse to the gate lines G1 to Gn, The horizontal line of the display panel 40 is selected.

The timing controller 10 rearranges the digital video data R, G and B from the system (not shown) in accordance with the liquid crystal display panel 40 and supplies the same to the data driver 20 and supplies the timing control signals Vsync and Hsync DCLK and DE to generate a data control signal DDC for controlling the data driver 20 and a gate control signal GDC for controlling the gate driver 30. [ The data control signal (DDCS) includes a source start pulse (SSP), a source shift clock (SSC), a source output enable (SOE) and a polarity (POL) And the gate control signal DDC includes a gate start pulse GSP, a gate shift clock GSC and a gate output enable signal GOE.

The driving voltage supply unit 50 has the first high potential driving voltage Vdrv1 swung between the high potential Vh and the low potential Vl and the first high potential driving voltage Vdrv1 having the opposite phase to the first high potential driving voltage Vdrv1, The second high potential driving voltage Vdrv2, and the low potential driving voltage Vbias. The driving voltage supplying unit 50 applies a first high potential driving voltage Vdrv (Vdr) to the odd high potential driving voltage supply lines VL1a, VL3a, ... VLn-1a connected in common to the touch sensor circuits of the odd numbered pixel rows, And supplies the second high potential driving voltage Vdrv2 to the high high potential driving voltage supply lines VL2a, VL4a, ... VLna commonly connected to the touch sensor circuits of the excellent pixel rows. In addition, the driving voltage supplier 50 supplies the low-potential driving voltage Vbias to the low-potential driving voltage supply lines VL1b to VLnb commonly connected to the touch sensor circuits of all the pixel rows.

The lead-out integrating unit 60 includes a plurality of circuits respectively connected to the lead-out lines ROL1 to RLOm of the liquid crystal display panel 40 as shown in FIG. 8, and the lead-out lines ROL1 to RLOm Amplifies the light sensing signal and outputs the amplified voltage. The liquid crystal display device according to the present invention can detect contact and / or contact position information of the user's finger based on the light sensing signal from the lead-out integration unit 60. [

The backlight unit 70 includes a plurality of lamps which are installed in a lower portion of the liquid crystal display panel 40 so as to overlap with the liquid crystal display panel 116. The lamp used in the backlight unit 70 can be any one of cold cathode fluorescent lamp (CCFL), external electrode fluorescent lamp (EEFL), and heat cathode fluorescent lamp (HCFL) have. The lamps irradiate light to the back surface of the liquid crystal display panel 40 by driving an inverter (not shown). Meanwhile, the backlight unit 70 may have a plurality of light emitting diodes instead of or in combination with the lamps.

FIG. 4 is an equivalent circuit diagram of a pixel 42 in which a touch sensor circuit according to the first embodiment of the present invention is formed, and FIGS. 5A and 5B are waveform diagrams showing a change in a first node voltage during a touch sensing operation.

4, a pixel 42 includes a pixel circuit P1 formed at an intersection of a j-th gate line Gj and a j-th data line Dj, a j-th high potential driving voltage supply line VLja, And a touch sensor circuit P2 formed at the intersection of the j-th low potential driving voltage supply line (VLjb) and the j-th lead-out line (ROLj).

The pixel circuit P1 includes a liquid crystal cell Clc and a pixel TFT TFT1 formed in a crossing region of the gate line Gj and the data line Dj for driving the liquid crystal cell Clc, And a first storage capacitor Cst1 for maintaining the charging voltage of the first storage capacitor Cst1 for one frame.

The pixel TFT TFT1 supplies a data voltage supplied through the data line DLj to the pixel electrode of the liquid crystal cell Clc in response to a scan pulse from the gate line GLj. To this end, the gate electrode of the pixel TFT (TFT1) is connected to the gate line GLj, the source electrode thereof is connected to the data line DLj, and the drain electrode thereof is connected to the pixel electrode of the liquid crystal cell Clc. The liquid crystal cell Clc is charged with the potential difference between the data voltage and the common voltage Vcom, and the arrangement of the liquid crystal molecules is changed by the electric field formed by this potential difference to adjust the light amount of the transmitted light or block the light. The first storage capacitor Cst1 is connected between the drain electrode of the pixel TFT (TFT1) and the low potential driving voltage supply line (VLjb).

 The touch sensor circuit P2 includes a sensor TFT (S-TFT) which generates a photocurrent i differently according to a change in the quantity of light incident from the outside, a second storage capacitor Cst2 that stores charges by the photocurrent i, And a switch TFT (TFT2) for switching the charges stored in the second storage capacitor (Cst2) to the lead-out line (ROLj).

The gate electrode of the sensor TFT (S-TFT) is connected to the low potential driving voltage supply line (VLjb), the source electrode is connected to the high potential driving voltage supply line (VLja), and the drain electrode is connected to the first node Respectively. A low potential driving voltage Vbias set to a voltage equal to or lower than the threshold voltage of the sensor TFT (S-TFT) is supplied to the gate electrode of the sensor TFT (S-TFT) And the first and second high potential driving voltages Vdrv1 and Vdrv2, which are swung between the low potential V1 and the low potential V1 and have phases opposite to each other. The sensor TFT (S-TFT) performs an optical sensing operation during a period in which the high-potential driving voltage supplied thereto is maintained at the high potential (Vh). On the other hand, the sensor TFT (S-TFT) stops the optical sensing operation during a period in which the high-potential driving voltage supplied to the sensor TFT (S-TFT) is maintained at the low potential (V1) Solves the degradation problem. This will be described in detail with reference to FIG. 6 and FIG. Unlike the pixel TFT (TFT1) and the switch TFT (TFT2), this sensor TFT (S-TFT) is not covered by the black matrix of the upper substrate. It is possible to detect a change in incident light amount. In other words, when an opaque material such as a pen or a user's finger is touched at its upper position to reflect light from the backlight unit to itself, the sensor TFT (S-TFT) responds to the reflected light to generate a photocurrent i ). Charges by the photocurrent i are stored in a second storage capacitor Cst2 connected between the first node N1 and the low potential drive voltage supply line VLjb.

The voltage VN1 of the first node is gradually increased by the charges stored in the second storage capacitor Cst2 until the switch TFT TFT2 is turned on as shown in Fig. On the other hand, if the opaque material is not touched by the sensor TFT (S-TFT) even if the high-potential driving voltage is maintained at the high potential Vh, the voltage VN1 of the first node is kept constant at the initial value do.

The switch TFT (TFT2) switches the charges stored in the second storage capacitor (Cst2) to the lead-out line (ROLj) and outputs a photo-sensing signal. To this end, the gate electrode of the switch TFT (TFT2) is connected to the (j-1) th gate line Gj-1, the source electrode thereof is connected to the first node N1 and the drain electrode thereof is connected to the lead out line ROLj Respectively. The switch TFT TFT2 is turned on in response to the scan pulse SPj-1 supplied to the (j-1) th gate line Gj-1 as shown in Figs. 5A and 5B, And outputs the node voltage VN1 as a light sensing signal to the lead-out line ROLj.

FIG. 6 is a view for explaining a connection structure of touch sensor circuits for cross driving in odd / even line units, and FIG. 7 is a waveform diagram of first and second high potential driving voltages supplied in the cross driving.

6 and 7, touch sensor circuits P2 (odd) formed on odd numbered pixel rows are connected to odd high potential driving voltage supply lines VL1a, VL3a, ... VLn-1a, respectively. And is commonly supplied with the first high potential driving voltage Vdrv1 generated in the driving voltage supply unit 50. [ The first high potential driving voltage Vdrv1 is swung between the high potential Vh and the low potential V1 and the potential level is inverted in one frame period 1v. The touch sensor circuits P2 (odd) formed on the odd numbered pixel rows perform a touch sensing operation in response to the first high potential driving voltage Vdrv1 supplied at the high potential Vh, The touch sensing operation is stopped in response to the first high potential driving voltage Vdrv1.

The touch sensor circuits P2 (even) formed on the excellent pixel rows are connected to the high-potential driving voltage supply lines VL2a, VL4a, ... VLna, respectively, 2 high potential driving voltage (Vdrv2). The second high potential driving voltage Vdrv2 has a phase opposite to the first high potential driving voltage Vdrv1 and is swung between the high potential Vh and the low potential Vl. The potential level is inverted. The touch sensor circuits P2 (even) formed on the excellent pixel rows perform a touch sensing operation in response to a second high potential driving voltage Vdrv2 supplied at a high potential Vh, And stops the touch sensing operation in response to the second high potential driving voltage Vdrv2.

As a result, the touch sensor circuits P2 (even) formed on the excellent pixel rows during the period in which the touch sensor circuits P2 (odd) formed on the odd number pixel rows perform the touch sensing operation, The touch sensor circuits P2 (even) formed on the excellent pixel rows during the period in which the touch sensor circuits P2 (odd) formed on the odd number pixel rows stop the touch sensing operation, And performs a sensing operation. As described above, in the liquid crystal display device having the touch sensor circuit according to the first embodiment of the present invention, the touch sensor circuits P2 formed on the lower substrate of the liquid crystal display panel are alternately driven Thereby preventing deterioration of the touch sensor circuits P2.

FIG. 8 is an equivalent circuit diagram for a part of the lead-out integration section, and FIG. 9 is a waveform diagram for explaining the operation of FIG. 9, Sreset, S1 and S2 are switch control signals generated by the timing control unit, and SPj-1 is a scan pulse supplied to the (j-1) th gate line.

8 and 9, the lead-out integration section includes an operational amplifier (not shown) having an inverting terminal (-) connected to the j-th lead-out line ROLj and a non-inverting terminal (+) connected to the reset voltage A capacitor Cfb connected between the inverting input node Ni and the output node No of the operational amplifier 62 and a capacitor Cfb connected between the inverting input node Ni of the operational amplifier 62 and the output node No A reset switch Sreset connected in parallel with the capacitor Cfb between the output node No and the first output line Lo1, a first switch S1 connected between the output node No and the first output line Lo1, And a second switch S2 connected between the second output line Lo2.

During the period A during which the reset signal Sreset control signal is kept in the high logic state, the operational amplifier 62 functions as a buffer and outputs the reset voltage Vreset supplied to the non-inverting terminal (+) to the output node No do. The reset voltage Vreset is output to the first output voltage Vo1 through the first output line Lo1 during the period C during which the first switch S1 is turned on after being stored in the capacitor Cfb for the B period. Here, the magnitude of the reset voltage Vreset is preferably set to be equal to the initial value as shown in FIG. 5B. The first node voltage VN1 of the touch sensor circuit is stored in the capacitor Cfb via the lead-out line ROLj and the input node Ni in synchronization with the supply of the scan pulse SPj- do. The first node voltage VN1 is output as the second output voltage Vo2 through the second output line Lo2 during the period E in which the second switch S2 is turned on. The second output voltage Vo2 is a value depending on the first node voltage VN1. The second output voltage Vo2 varies depending on whether the opaque material is touched or not and the potential level of the driving voltage supplied to the touch sensor circuit. That is, if the opaque material is not touched on the upper part of the touch sensor circuit even if the driving voltage is supplied to the low potential or the driving voltage is supplied to the high potential, the second output voltage Vo2 is outputted as the same value as the first output voltage Vo1 do. On the other hand, when the opaque material is touched on the upper part of the touch sensor circuit during the period when the driving voltage is supplied to the high potential, the value of the second output voltage Vo2 is outputted as a value different from the first output voltage Vo1. The liquid crystal display according to the present invention processes the difference between the first and second output voltages Vo1 and Vo2 into a digital signal through an analog-to-digital converter (not shown), and then the digital signal and the touch sensor circuit are included The position of the currently touched point can be grasped and applied to various applications.

10 is an equivalent circuit diagram of a touch sensor circuit according to a second embodiment of the present invention.

Referring to Fig. 10, the touch sensor circuit according to the second embodiment of the present invention includes two sensor TFTs (S-TFT1, S-TFT2) in one touch sensor circuit.

The low-potential driving voltage Vbias is commonly applied to the gate electrodes of the first and second sensor TFTs S-TFT1 and S-TFT2, and the first and second sensor TFTs S-TFT1 and S- Are commonly connected to the first node N1. A second storage capacitor Cst2 is connected between the first node N1 and the gate electrodes of the sensor TFTs. A switch for outputting the first node voltage VN1 as a light sense signal to the lead out line ROL in response to the scan pulse SP from the previous gate line is provided between the first node N1 and the lead out line ROL. And a TFT (TFT2) is connected.

The first high potential driving voltage Vdrv1 is supplied to the source electrode of the first sensor TFT S-TFT1 while the second high potential driving voltage Vdrv2 is supplied to the source electrode of the second sensor TFT S- .

The first high potential driving voltage Vdrv1 is swung between the high potential Vh and the low potential Vl as shown in FIG. 7, and the potential level is inverted in one frame period 1v. The second high potential driving voltage Vdrv2 has a phase opposite to the first high potential driving voltage Vdrv1 and swings between the high potential Vh and the low potential Vl as shown in FIG. ), The potential level is inverted. Therefore, the first sensor TFT (S-TFT1) performs a touch sensing operation in response to the first high potential driving voltage (Vdrv1) supplied at a high potential (Vh) The touch sensing operation is stopped in response to the above driving voltage Vdrv1. The second sensor TFT (S-TFT2) performs a touch sensing operation in response to a second high potential driving voltage (Vdrv2) supplied at a high potential (Vh), and a second high potential driving And stops the touch sensing operation in response to the voltage Vdrv2.

As a result, during the period in which all the first sensor TFTs (S-TFT1) perform a touch sensing operation in all the touch sensor circuits, the second sensor TFTs (S-TFT2) of all the touch sensor circuits stop the touch sensing operation . On the other hand, during the period in which all the second sensor TFTs (S-TFT2) perform a touch sensing operation in common to all the touch sensor circuits, the first sensor TFTs (S-TFT1) of all the touch sensor circuits stop the touch sensing operation . As described above, in the liquid crystal display device having the touch sensor circuit according to the second embodiment of the present invention, two sensor TFTs are disposed in each of the touch sensor circuits, and the sensor TFTs are cross-driven to prevent deterioration of the touch sensor circuit .

As described above, in the liquid crystal display device and the driving method thereof according to the present invention, the touch sensor circuits formed on the lower substrate of the liquid crystal display panel are alternately driven by the priming / right priming to prevent deterioration of the touch sensor circuits Malfunction of the touch sensor circuits can be prevented and reliability can be improved.

Further, in the liquid crystal display device and the driving method thereof according to the present invention, two sensor TFTs are disposed in each of the touch sensor circuits, and the sensor TFTs are cross-driven to prevent deterioration of the touch sensor circuit, thereby preventing malfunction of the touch sensor circuits So that the reliability can be enhanced.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

1 is an equivalent circuit diagram of a liquid crystal display device of an active matrix type.

2 is a diagram for explaining the operation of the touch sensor circuit;

FIG. 3 is a block diagram showing a liquid crystal display device according to the present invention. FIG.

FIG. 4 is an equivalent circuit diagram of a pixel in which a touch sensor circuit according to a first embodiment of the present invention is formed; FIG.

5A and 5B are waveform diagrams showing changes in the first node voltage during the touch sensing operation;

6 is a diagram for explaining a connection structure of touch sensor circuits for cross driving in odd / even line units;

7 is a waveform diagram of first and second high potential driving voltages supplied during the cross driving;

Figure 8 is an equivalent circuit diagram for a portion of the lead-out integration section.

FIG. 9 is a waveform diagram for explaining the operation of FIG. 8; FIG.

FIG. 10 is an equivalent circuit diagram of a touch sensor circuit according to a second embodiment of the present invention; FIG.

Claims (10)

A plurality of pixels defined as an intersection of gate lines and data lines; A plurality of touch sensor circuits driven by driving voltages to sense external light and generate a light sensing signal; A plurality of lead-out lines for outputting the photo-sensing signal; A first high potential driving voltage supply line connected in common to the odd numbered pixel rows to supply a high potential driving voltage to the touch sensor circuits formed on the odd numbered pixel rows; A second high potential driving voltage supply line commonly connected to the excellent pixel rows to supply the high potential driving voltage to the touch sensor circuits formed on the excellent pixel rows; And Intermittently applying the high potential driving voltage to each of the first and second high potential driving voltage supply lines and alternately applying the high potential driving voltage to the first and second high potential driving voltage supply lines And a driving voltage supply unit. The method according to claim 1, Wherein the period during which the high-potential driving voltage is intermittently applied is a one vertical period. The method according to claim 1, The driving voltage supply unit includes: And supplies a low potential driving voltage commonly to the touch sensor circuits formed on the odd and even pixel rows through a low potential driving voltage supply line commonly connected to the odd and even pixel rows. delete The method according to claim 1, The touch sensor circuit includes: A gate electrode connected to the low potential driving voltage supply line commonly connected to the odd and even pixel rows, a source electrode connected to any one of the first and second high potential driving voltage supply lines, A sensor TFT having a drain electrode to which a source-drain channel current flows by the external light when the high-potential driving voltage is applied; A storage capacitor connected between the low potential driving voltage supply line and the first node and storing charges due to the channel current; And And a switching TFT for outputting the accumulated charge as one of the lead-out lines as the photo-sensing signal. 6. The method of claim 5, And a lead-out integration unit connected to the lead-out lines for amplifying the photo-sensing signal from the lead-out lines and outputting the amplified voltage. The method according to claim 1, Wherein the touch sensor circuit is formed at an interval of a length larger than the pixel. A plurality of pixels defined as an intersection of gate lines and data lines; A plurality of touch sensor circuits for sensing external light and generating a photo sensing signal using high potential driving voltages respectively supplied to first and second sensor TFTs formed in a part of the pixels and connected in parallel; A plurality of lead-out lines for outputting the photo-sensing signal; A first high potential driving voltage supply line for supplying a high potential driving voltage to the first sensor TFT; A second high-potential driving voltage supply line for supplying the high-potential driving voltage to the second sensor TFT; And Intermittently applying the high potential driving voltage to each of the first and second high potential driving voltage supply lines and alternately applying the high potential driving voltage to the first and second high potential driving voltage supply lines And a driving voltage supply unit. A plurality of pixels defined by the intersection of the gate lines and the data lines, a plurality of touch sensor circuits driven by the driving voltages to sense external light and generate a light sensing signal, A method of driving a liquid crystal display having a plurality of lead-out lines, Supplying a high potential driving voltage to the touch sensor circuits formed on the odd number pixel rows through a first high potential driving voltage supply line commonly connected to the odd number pixel rows; And Supplying the high potential driving voltage to the touch sensor circuits formed on the fine pixel rows through a second high potential driving voltage supply line commonly connected to the fine pixel lines; The high-potential driving voltage is applied to each of the first and second high-potential driving voltage supply lines, and is alternately applied to the first and second high-potential driving voltage supply lines. . A plurality of pixels defined as intersections of the gate lines and the data lines, a plurality of pixels connected to the first and second sensor TFTs formed in a part of the pixels and connected in parallel, A method of driving a liquid crystal display having a plurality of touch sensor circuits for generating a backlight sensing signal and a plurality of leadout lines for outputting the sensing signal, Supplying a high potential driving voltage to the first sensor TFT through a first high potential driving voltage supply line; And And supplying the high potential driving voltage to the second sensor TFT through a second high potential driving voltage supply line; The high-potential driving voltage is applied to each of the first and second high-potential driving voltage supply lines, and is alternately applied to the first and second high-potential driving voltage supply lines. .

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