KR20090005603A - Liquid crystal display device and method for driving thereof - Google Patents

Abstract

A liquid crystal display and a method for driving the same are provided to improve the reliability by preventing mis-operation of a touch sensing circuit. A plurality of pixels(42) is defined as the intersection of the data lines and gate lines. A plurality of touch sensor circuits senses generates light sensing signal after sensing the external light. A first high potential driving voltage supplying line supplies high potential driving voltage to touch sensing circuits which are formed on odd number pixel line. A second high potential driving voltage supplying line supplies high potential driving voltage to touch sensing circuits which are formed on the even number pixel line. The drive voltage supplier(50) applies the high potential driving voltage to each first and second high voltage driving electric pressure supply lines.

Description

Liquid Crystal Display Device And Method For Driving Thereof}

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 capable of increasing the reliability of the 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 corresponding to the video signal. The liquid crystal display is a flat panel display 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 having such a configuration is rapidly replacing a cathode ray tube (CRT) due to its thinness and low power consumption.

In particular, an active matrix type liquid crystal display device in which switching elements are formed in each liquid crystal cell is advantageous in implementing a moving image because active control of the switching element is possible.

As the switching element used in the active matrix liquid crystal display device, a thin film transistor (hereinafter referred to as TFT) is mainly used as shown in FIG. 1.

Referring to FIG. 1, an active matrix type liquid crystal display converts digital input data into an analog data voltage based on a gamma reference voltage and supplies it to the data line DL and simultaneously supplies scan pulses to the gate line GL. The liquid crystal cell Clc is charged. For this purpose, the gate electrode of the TFT is connected to the gate line GL, the source electrode 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. It is connected to one electrode. The common voltage Vcom is supplied to the common electrode of the liquid crystal cell Clc. The storage capacitor Cst1 charges a data voltage applied from the data line DL when the TFT is turned on to maintain a constant voltage of the liquid crystal cell Clc. When the 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 so that the voltage on the data line DL is applied to the pixel electrode of the liquid crystal cell Clc. Supply. At this time, the liquid crystal molecules of the liquid crystal cell Clc modulate the incident light by changing the arrangement by the electric field between the pixel electrode and the common electrode.

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 rear surface of the liquid crystal display panel.

On the other hand, the touch screen panel (Touch Screen Panel) is generally one of the user interface that detects the touch point by changing the electrical characteristics at the touch point that is attached to the display device in contact with the hand or pen, the application range of It is expanding into the field. The liquid crystal display device with a touch screen panel detects whether the user's finger or touch pen touches the screen and the contact position information, and implements various applications using the detection information. have.

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

In order to solve the above-mentioned problems, a technique of forming a touch sensor circuit including the sensor TFT as shown in FIG. 2 instead of the touch screen panel in the liquid crystal cell Clc of the liquid crystal display has been developed. The touch sensor circuit includes a sensor TFT that generates a photocurrent i differently according to a change in the amount of light incident from the outside, a storage capacitor Cst2 for storing charges by the photocurrent i, and a charge stored in the storage capacitor Cst2. And a switch TFT for outputting the light, and detecting a change in light by a user's finger or the like, and outputting the light detection signal to the outside. Here, the low potential bias voltage Vbias set to a voltage below its threshold voltage is supplied to the gate electrode of the sensor TFT. The liquid crystal display device can determine whether the user's finger or the like is contacted and / or contact position information based on the light detection signal of the touch sensor circuit.

However, for such a light sensing operation, the sensor TFT has a problem that it is easily deteriorated when driving for a long time because it must always be supplied with a high potential direct current driving voltage (Vdrv) through its drain electrode. When the sensor TFT is deteriorated, a large error may occur in the output detection signal because the output characteristic of the touch sensor circuit is changed. In other words, the touch sensor circuit may output a non-contact detection signal even when the user's finger or the like touches the liquid crystal cell in which the touch sensor circuit is formed. Is likely to output

Accordingly, an object of the present invention is to provide a liquid crystal display device and a method of driving the same, which can improve the reliability of a touch sensor circuit.

In order to achieve the above object, a liquid crystal display according to an embodiment of the present invention comprises a plurality of pixels defined by the intersection of the gate line and the data line; A plurality of touch sensor circuits driven by driving voltages to sense external light and to generate a light sensing signal; A first high potential drive voltage supply line commonly connected to odd pixel rows to supply a high potential drive voltage to touch sensor circuits formed in the odd pixel rows; A second high potential drive voltage supply line commonly connected to even pixel rows to supply the high potential drive voltage to touch sensor circuits formed in the even 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 one vertical period.

The driving voltage supply unit commonly supplies a low potential driving voltage to touch sensor circuits formed in 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 according to the exemplary embodiment of the present invention further includes a plurality of lead out lines for outputting the light sensing signal.

The touch sensor circuit may include a gate electrode connected to the low potential driving voltage supply line, a source electrode connected to any 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 to accumulate charge by the channel current; And a switching TFT which outputs the accumulated charge to the one of the lead-out lines as the light sensing signal.

The liquid crystal display according to the exemplary embodiment of the present invention further includes a readout integration unit connected to the readout lines to amplify the light sensing signals from the readout lines and output the amplified voltage.

The touch sensor circuits are formed at intervals of a length greater than that of the pixels.

According to another exemplary embodiment of the present invention, a liquid crystal display includes: a plurality of pixels defined by intersections of gate lines and data lines; A plurality of touch sensor circuits configured to sense external light by using high potential driving voltages formed in some of the pixels and respectively supplied to the first and second sensor TFTs connected in parallel; A first high potential drive voltage supply line supplying a high potential drive voltage to the first sensor TFT; A second high potential drive voltage supply line supplying the high potential drive 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.

According to an embodiment of the present invention, a plurality of pixels defined as intersections of gate lines and data lines, and a liquid crystal having a plurality of touch sensor circuits driven by driving voltages to detect external light and then generate a light sensing signal A method of driving a display device includes supplying a high potential driving voltage to touch sensor circuits formed in the odd pixel rows through a first high potential driving voltage supply line commonly connected to the odd pixel rows; And supplying the high potential drive voltage to touch sensor circuits formed in the even pixel rows through a second high potential drive voltage supply line commonly connected to the even pixel rows. The high potential driving voltage is intermittently 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.

According to another exemplary embodiment of the present invention, a plurality of pixels defined as intersections of gate lines and data lines, and a high potential driving are respectively supplied to first and second sensor TFTs formed in some of the pixels and connected in parallel. A driving method of a liquid crystal display device having a plurality of touch sensor circuits for sensing external light using voltages may include 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 drive voltage to the second sensor TFT through a second high potential drive 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 is alternately applied to the first and second high potential driving voltage supply lines.

The liquid crystal display and the driving method thereof according to the present invention can increase reliability by preventing malfunction of the touch sensor circuit by intermittently applying a high potential driving voltage supplied to the touch sensor circuit to prevent deterioration of the touch sensor circuit.

Other objects and advantages of the present invention in addition to the above object will be apparent from the description of the preferred embodiments of the present invention with reference to the accompanying drawings.

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

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

Referring to FIG. 3, the liquid crystal display according to the present invention crosses 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. And a liquid crystal display panel 40 having pixels 42 having a touch sensor circuit at the intersection thereof, a data driver 20 for supplying a data voltage to the data lines D1 to Dm, and gate lines. A gate driver 30 for supplying scan pulses to the G1 to Gn, a timing controller 10 for controlling driving timings of the data driver 20 and the gate driver 30, and driving voltage supply lines ( The driving voltage supply unit 50 for supplying driving voltages to the 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. On the rear surface of the lead-out integrated unit 60 and the liquid crystal display panel 40 connected in common 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.

On the lower substrate of the liquid crystal display panel 40, a plurality of data lines D1 to Dm and a plurality of gate lines G1 to Gn are orthogonal to each other and are parallel to the gate lines G1 to Gn. A plurality of readout lines ROL1 to ROLm 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 are formed. 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-out lines The touch sensor circuit P2 shown in FIG. 4 is formed at the intersection of ROL1 to ROLm. Each of the driving voltage supply lines VL1 to VLn has a high potential driving voltage supply lines VL1a to VLna for supplying a high potential driving voltage to the touch sensor circuit P2, and a low potential to the touch sensor circuit P2. Low potential driving voltage supply lines VL1b to VLnb for supplying a driving voltage are included. The touch sensor circuit P2 detects a change in external light input to the self, and generates a light detection signal, and supplies the light detection signal to the readout integration unit 60 through the leadout lines ROL1 to ROLm. . Meanwhile, the touch sensor circuit P2 may be disposed for each pixel 42, but may be formed at intervals of a length greater than that of the pixel to improve the aperture ratio.

A black matrix is formed on the upper substrate of the liquid crystal display panel 40 to cover the boundary between the color filters and the pixels. The common electrode supplied with the common voltage facing the pixel electrode with the liquid crystal layer interposed therebetween is formed on the upper substrate in TN (Twisted Nematc) mode, VA mode (Vertical Alignment) mode, and the like. In Plane Switching (IPS) mode and FFS mode It is formed on the lower substrate in the (Fringe Field Switching) mode.

In addition, the upper and lower substrates of the liquid crystal display panel 40 are formed with polarizers for selecting linear polarization and alignment films for determining pretilt of liquid crystal molecules.

The data driver 20 receives the digital video data R, G, and B from the gamma reference voltage generator (not shown) in response to the data control signal DDC from the timing controller 10. ) Is converted into an analog gamma compensation voltage, and the analog gamma compensation voltage is supplied 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 pulses to the gate lines G1 to Gn to supply a data voltage. The horizontal line of the display panel 40 is selected.

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

The driving voltage supply unit 50 has a phase opposite to that of the first high potential driving voltage Vdrv1 and the first high potential driving voltage Vdrv1 swinging between the high potential Vh and the low potential Vl as shown in FIG. 7. The second high potential driving voltage Vdrv2 and the low potential driving voltage Vbias are generated. In addition, the driving voltage supply unit 50 may supply the first high potential driving voltage Vdrv to the odd high potential driving voltage supply lines VL1a, VL3a,... VLn-1a that are commonly connected to the touch sensor circuits of the odd pixel rows. The second high potential driving voltage Vdrv2 is supplied to the even high potential driving voltage supply lines VL2a, VL4a,... VLna commonly connected to the touch sensor circuits of the even pixel rows. In addition, the driving voltage supply unit 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 integrated 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 may include the lead-out lines ROL1 to RLOm. Amplify the light detection signal to output the amplified voltage. The liquid crystal display according to the present invention can find out whether the user's finger or the like and / or contact position information based on the light detection signal from the lead-out integrated unit 60.

The backlight unit 70 includes a plurality of lamps disposed below the liquid crystal display panel 40 to overlap the liquid crystal display panel 116. The lamp used in the backlight unit 70 may be any one of a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and a heat cathode fluorescent lamp (HCFL). have. The lamps irradiate light onto the rear surface of the liquid crystal display panel 40 by driving an inverter (not shown). Meanwhile, the backlight unit 70 may include 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 having a touch sensor circuit according to a first embodiment of the present invention, and FIGS. 5A and 5B are waveform diagrams illustrating changes in first node voltage during a touch sensing operation.

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

The pixel circuit P1 is formed at the intersection of the liquid crystal cell Clc, the gate line Gj and the data line Dj, and the pixel TFT TFT1 for driving the liquid crystal cell Clc, and the liquid crystal cell Clc. A first storage capacitor Cst1 for maintaining a charging voltage of

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. For this purpose, the gate electrode of the pixel TFT TFT1 is connected to the gate line GLj, the source electrode is connected to the data line DLj, and the drain electrode is connected to the pixel electrode of the liquid crystal cell Clc. The liquid crystal cell Clc is charged with a 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 the potential difference to control the amount of light transmitted or to 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 may include a sensor TFT S-TFT that generates a photocurrent i differently according to a change in the amount 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 readout 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 N1. Connected. The low potential driving voltage Vbias set to a voltage below its threshold voltage is supplied to the gate electrode of the sensor TFT (S-TFT), and the high potential Vh is provided to the source electrode of the sensor TFT (S-TFT) as shown in FIG. 7. ) And one of the first and second high potential driving voltages Vdrv1 and Vdrv2 swinging between the low potential V1 and the phases opposite to each other. The sensor TFT (S-TFT) performs the light sensing operation during the 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 light sensing operation during the period in which the high-potential driving voltage supplied to the low potential (Vl) is maintained, so that the sensor TFT (S-TFT) Solve the degradation problem. This will be described in detail with reference to FIGS. 6 and 7. Since the sensor TFT (S-TFT) is not covered by the black matrix of the upper substrate, unlike the pixel TFT (TFT1) and the switch TFT (TFT2), the sensor TFT (S-TFT) is supplied from the outside during the period in which the high potential driving voltage is maintained at the high potential Vh. It is possible to detect a change in the amount of incident light. In other words, when an opaque material such as a pen or a user's finger is touched at its upper position and reflects light from the backlight unit to itself, the sensor TFT (S-TFT) responds to the reflected light in response to the photocurrent i. Will occur). Charges by the photocurrent i are stored in the second storage capacitor Cst2 connected between the first node N1 and the low potential driving voltage supply line VLjb.

Due to the charges stored in the second storage capacitor Cst2, the voltage VN1 of the first node gradually increases until the switch TFT TFT2 is turned on as shown in FIG. 5A. Meanwhile, even when the high potential driving voltage is maintained at the high potential Vh, if the opaque material is not touched by the sensor TFT (S-TFT), the voltage VN1 of the first node is kept constant at an initial value as shown in FIG. 5B. do.

The switch TFT TFT2 switches the charges stored in the second storage capacitor Cst2 to the readout line ROLj and outputs a light 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 is connected to the first node N1, and the drain electrode is connected to the readout line ROLj. Connected. As shown in FIGS. 5A and 5B, the switch TFT TFT2 is turned on in response to the scan pulse SPj-1 supplied to the j−1th gate line Gj−1 so that the first switch TFT TFT2 is turned on for the first frame period 1V. The node voltage VN1 is output to the readout line ROLj as a light detection signal.

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

6 and 7, the touch sensor circuits P2 (odd) formed in the odd pixel rows are connected to the odd high potential driving voltage supply lines VL1a, VL3a, ... VLn-1a, respectively. As a result, the first high potential driving voltage Vdrv1 generated by the driving voltage supply unit 50 is commonly supplied. The first high potential driving voltage Vdrv1 is swinged between the high potential Vh and the low potential Vl, and its potential level is inverted every one frame period 1v. The touch sensor circuits P2 (odd) formed in the odd pixel rows perform a touch sensing operation in response to the first high potential driving voltage Vdrv1 supplied to the high potential Vh, and low potential Vl. The touch sensing operation is stopped in response to the first high potential driving voltage Vdrv1 supplied to.

The touch sensor circuits P2 (even) formed in the even pixel rows are connected to the even high potential driving voltage supply lines VL2a, VL4a,... VLna, respectively, and are generated by the driving voltage supply unit 50. 2 High potential drive voltage Vdrv2 is commonly supplied. The second high potential driving voltage Vdrv2 has a phase opposite to that of the first high potential driving voltage Vdrv1 and is swinged between the high potential Vh and the low potential Vl, and the second high potential driving voltage Vdrv2 has a period of one frame period 1v. The potential level is reversed. The touch sensor circuits P2 (even) formed in the even pixel rows perform a touch sensing operation in response to the second high potential driving voltage Vdrv2 supplied to the high potential Vh, and the low potential Vl. The touch sensing operation is stopped in response to the second high potential driving voltage Vdrv2.

As a result, the touch sensor circuits P2 (even) formed in the even pixel rows are touch sensed during the period in which the touch sensor circuits P2 (odd) formed in the odd pixel rows perform the touch sensing operation. On the contrary, the touch sensor circuits P2 (even) formed in the even pixel rows are touched while the touch sensor circuits P2 (odd) formed in the odd pixel rows stop the touch sensing operation. Perform the 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 to perform an odd run / excellent run. The degradation of the touch sensor circuits P2 is prevented.

FIG. 8 is an equivalent circuit diagram of a part of the readout integrated unit, and FIG. 9 is a waveform diagram illustrating the operation of FIG. 8. 9, Sreset, S1, and S2 are switch control signals generated by the timing controller, and SPj-1 is a scan pulse supplied to the j-1 th gate line.

8 and 9, the lead-out integrated unit has an op amp having a reverse terminal (−) connected to the j-th lead-out line ROLj and a non-inverting terminal (+) connected to a reset voltage Vreset supply line. And the capacitor Cfb connected between the inverting input node Ni of the op amp 62 and the output node No, and the inverting input node Ni and the output node No of the op amp 62. The reset switch (Sreset) connected in parallel with the capacitor (Cfb) between the first, the first switch (S1) and the output node (No) connected between the output node (No) and the first output line (Lo1) A second switch S2 is connected between the second output line Lo2.

During the period A during which the reset switch control signal remains in a high logic state, the operational amplifier 62 acts as a buffer to output the reset voltage Vreset supplied to the non-inverting terminal (+) to the output node No. do. The reset voltage Vreset is stored in the capacitor Cfb for the period B and then output to the first output voltage Vo1 through the first output line Lo1 during the period C where the first switch S1 is turned on. Here, the magnitude of the reset voltage Vreset is preferably set equal to the initial value as shown in FIG. 5B. Subsequently, the first node voltage VN1 of the touch sensor circuit is stored in the capacitor Cfb via the readout line ROLj and the input node Ni in synchronization with the supply of the scan pulse SPj-1 during the D period. do. The first node voltage VN1 is output to the second output voltage Vo2 through the second output line Lo2 during the E period in which the second switch S2 is turned on. The second output voltage Vo2 is a value that depends on the first node voltage VN1 and varies depending on whether the opaque material is touched on the touch sensor circuit and the potential level of the driving voltage supplied to the touch sensor circuit. That is, even when the driving voltage is supplied at a low potential or the driving voltage is supplied at a high potential, the second output voltage Vo2 is output at the same value as the first output voltage Vo1 when the opaque material is not touched on the touch sensor circuit. do. On the other hand, when the opaque material is touched on the touch sensor circuit during the period in which the driving voltage is supplied at the high potential, the value of the second output voltage Vo2 is output to be 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 includes the digital signal and the touch sensor circuit. By using the position information of the pixel to be detected the exact position of the point being touched can be applied to a variety of 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 and S-TFT2 in one touch sensor circuit.

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-TFT2. The drain electrodes of the first node N1 are commonly connected. A second storage capacitor Cst2 is connected between the first node N1 and the gate electrodes of the sensor TFTs. A switch that outputs the first node voltage VN1 to the readout line ROL as a light sensing signal in response to the scan pulse SP from the front gate line between the first node N1 and the readout line ROL. 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-TFT2. Supplied.

The first high potential driving voltage Vdrv1 is swinged between the high potential Vh and the low potential V1 as shown in FIG. 7, but its potential level is inverted every one frame period 1v. As shown in FIG. 7, the second high potential driving voltage Vdrv2 has a phase opposite to that of the first high potential driving voltage Vdrv1 and is swinged between the high potential Vh and the low potential Vl, and thus, one frame period 1v. The potential level is reversed by the cycle. Accordingly, the first sensor TFT S-TFT1 performs a touch sensing operation in response to the first high potential driving voltage Vdrv1 supplied to the high potential Vh, and the first high potential supplied to the low potential Vl. 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 the second high potential driving voltage Vdrv2 supplied to the high potential Vh, and the second high potential drive supplied to the low potential Vl. The touch sensing operation is stopped in response to the voltage Vdrv2.

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

As described above, the liquid crystal display device and the driving method thereof according to the present invention prevents deterioration of the touch sensor circuits by alternately driving the touch sensor circuits formed on the lower substrate of the liquid crystal display panel into odd rows / excellent rows. The malfunction of the touch sensor circuits can be prevented to increase reliability.

Furthermore, the liquid crystal display device and the driving method thereof according to the present invention prevent the malfunction of the touch sensor circuits by arranging two sensor TFTs in the touch sensor circuits and cross-driving the sensor TFTs to prevent deterioration of the touch sensor circuit. To increase the reliability.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present 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 an active matrix liquid crystal display device.

2 is a view for explaining the operation of the touch sensor circuit.

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

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.

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

6 is a view for explaining a connection structure of touch sensor circuits for cross driving in odd / excellent line units.

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

8 is an equivalent circuit diagram of a portion of the lead-out integrated unit.

9 is a waveform diagram illustrating the operation of FIG. 8.

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

Claims (10)

A plurality of pixels defined by the intersection of the gate lines and the data lines; A plurality of touch sensor circuits driven by driving voltages to sense external light and to generate a light sensing signal; A first high potential drive voltage supply line commonly connected to odd pixel rows to supply a high potential drive voltage to touch sensor circuits formed in the odd pixel rows; A second high potential drive voltage supply line commonly connected to even pixel rows to supply the high potential drive voltage to touch sensor circuits formed in the even 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 of claim 1, And a period in which the high potential driving voltage is intermittently applied is one vertical period. The method of claim 1, The driving voltage supply unit, And a low potential driving voltage in common to touch sensor circuits formed in the odd and even pixel rows through a low potential driving voltage supply line commonly connected to the odd and even pixel rows. The method of claim 3, wherein And a plurality of lead-out lines for outputting the light sensing signal. The method of claim 4, wherein The touch sensor circuit, The high potential having a gate electrode connected to the low potential driving voltage supply line, a source electrode connected to any one of the first and second high potential driving voltage supply lines, and a drain electrode connected to a first node; A sensor TFT through which a source-drain channel current flows by the external light when a driving voltage is applied; A storage capacitor connected between the low potential driving voltage supply line and the first node to accumulate charge by the channel current; And And a switching TFT which outputs the accumulated charge to the one of the lead-out lines as the light sensing signal. The method of claim 5, wherein And a lead-out integrated unit connected to the lead-out lines to amplify the light sensing signals from the lead-out lines and output an amplified voltage. The method of claim 1, And the touch sensor circuit is formed at intervals of a length greater than that of the pixel. A plurality of pixels defined by the intersection of the gate lines and the data lines; A plurality of touch sensor circuits configured to sense external light by using high potential driving voltages formed in some of the pixels and respectively supplied to the first and second sensor TFTs connected in parallel; A first high potential drive voltage supply line supplying a high potential drive voltage to the first sensor TFT; A second high potential drive voltage supply line supplying the high potential drive 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 driving method of a liquid crystal display device having a plurality of pixels defined by intersections of gate lines and data lines, and a plurality of touch sensor circuits driven by driving voltages to sense external light and generating a light sensing signal. Supplying a high potential drive voltage to touch sensor circuits formed in the odd pixel rows through a first high potential drive voltage supply line commonly connected to odd pixel rows; And Supplying the high potential drive voltage to touch sensor circuits formed in the even pixel rows through a second high potential drive voltage supply line commonly connected to the even pixel rows; The high potential driving voltage is intermittently 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. Driving method. Detecting external light using a plurality of pixels defined by intersections of gate lines and data lines, and high potential driving voltages respectively provided to first and second sensor TFTs formed in some of the pixels and connected in parallel; In the driving method of a liquid crystal display device having a plurality of touch sensor circuits, 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 drive voltage to the second sensor TFT through a second high potential drive 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 is alternately applied to the first and second high potential driving voltage supply lines. Driving method.

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