KR20090116223A - Liquid crystal display device and method for driving thereof - Google Patents

Abstract

PURPOSE: A liquid crystal display device and a driving method thereof are provided to improve reliability of touch recognition by including the information about a touch point in the touch position information by a finger without the influence of the external light. CONSTITUTION: A timing controller generates a first gate start pulse and a second gate start pulse corresponding to a first period and a second period. A readout integrated circuit converts a photo current from a touch sensor circuit into a photo sense data. A RGB scan storage(82) stores the photo sense data supplied from the readout integrated circuit for a first period synchronized with a first gate start pulse. A BD scan storage(84) stores the photo sense data supplied from the readout integrated circuit for a second period synchronized with a second gate start pulse. A difference extractor(86) extracts the difference of the compared data by comparing the photo sense data from the RGB scan storage and the BD scan storage one to one. The system performs a process for touch recognition by applying the touch position information to the touch recognition algorithm.

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 of a touch panel in cell type, and more particularly, to a liquid crystal display device and a method of driving the same, which simplify the algorithm of touch recognition and increase the reliability of touch recognition. .

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. 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 picture because active switching of the switching elements is possible.

As a switching element used in an 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 video 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 data voltage is charged in the liquid crystal cell Clc. 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.

On the other hand, the liquid crystal display device is a passive light emitting device, and adjusts the brightness of the screen by using the backlight generated from the backlight unit disposed on the rear surface of the liquid crystal display panel.

Recently, a technology for attaching a touch screen panel on such a liquid crystal display has been proposed. A touch screen panel generally refers to a user interface attached to a display device to detect a touch point by changing electrical characteristics at a touch point that contacts an opaque object such as a finger or a pen. When a user's finger or touch pen touches a screen, the liquid crystal display with a touch screen panel detects contact position information and implements various applications based on the detected information. have.

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

In order to solve the above-mentioned problems, in recent years, instead of the touch screen panel, a cell panel, a touch panel which forms a touch sensor circuit including the sensor TFT as shown in FIG. 2 inside the liquid crystal cell Clc of the liquid crystal display, has been proposed. . The touch sensor circuit has a sensor TFT that generates a photocurrent i differently according to a change in the amount of light incident from the outside, a sensor capacitor Cst2 for storing charges by the photocurrent i, and outputs of charges stored in the sensor capacitor Cst2. It includes a switch TFT for switching the. The bias voltage Vbias set to a voltage below its threshold voltage is supplied to the gate electrode of the sensor TFT. In the light sensor environment (indoor environment) that is darker than the backlight, the touch sensor circuit has a larger light current of the sensor TFT corresponding to the touched part than the light current of the sensor TFT corresponding to the non-touched part, whereas the light sensor environment (outdoor environment) is higher than that of the backlight. ), The photocurrent of the sensor TFT corresponding to the touched portion is smaller than the photocurrent of the sensor TFT corresponding to the non-touched portion, thereby generating different photodetection signals at the touched or untouched portion. The liquid crystal display device can detect contact position information of a user's finger or the like using a touch recognition algorithm operated based on the light sensing signal of the touch sensor circuit.

FIG. 3 illustrates a result of sensing a touched part in a conventional liquid crystal display device which is a touch panel. In FIG. 3, "A" represents a touch point by the finger, "B" represents a portion where external light is blocked by the finger, and "C" represents a portion exposed to the external light, respectively. Here, "A" has a data value brighter than "B" by reflection of backlight light due to touch.

However, such a touch panel, a cell-type liquid crystal display device, causes all of the touch recognition algorithms to be applied to the algorithm up to "C" in addition to "A" in order to extract the touched part. In addition, since the touch panel, a cell-type liquid crystal display device applies all algorithms up to "C" in addition to "A" in order to extract the touched part, the data values of "A" and "C" are similar, that is, " If the brightness of A "and" C "is similar, the reliability of touch recognition is deteriorated.

Accordingly, an object of the present invention is to provide a liquid crystal display device and a driving method thereof which simplify the algorithm of touch recognition and increase the reliability of touch recognition.

In order to achieve the above object, a liquid crystal display according to an exemplary embodiment of the present invention includes a plurality of pixels including a touch sensor circuit that generates a photo current differently depending on whether a pixel circuit and a touch are formed at each intersection of gate lines and data lines. A liquid crystal display panel having normal, display normal data RGB for a first period, and display black data BD for a second period following the first period; A timing controller configured to generate first and second gate start pulses corresponding to the first and second periods, respectively; A readout integrated circuit for converting a photocurrent from the touch sensor circuit into photosensitive data; A touch for generating the touch location information in which the light sensing data is generated and separated during the first period and generated during the second period, and extracting a difference value of the separated and stored light sensing data to exclude the influence of external light. Position information detection circuit; And a system for performing a processor process for touch recognition by applying the touch location information to a touch recognition algorithm.

The touch position information detecting circuit may include: an RGB scan storage unit configured to store light sensing data supplied from the readout integrated circuit during the first period synchronized with the first gate start pulse; A BD scan storage unit for storing optical sensing data supplied from the readout integrated circuit during the second period synchronized with the second gate start pulse; And a difference value extraction unit for comparing the light sensing data from the RGB scan storage unit and the BD scan storage unit one-to-one, and extracting the difference value of the compared data as a result.

The first and second gate start pulses are sequentially generated by time division of one frame period.

According to another exemplary embodiment of the present invention, a liquid crystal display device includes: a liquid crystal display panel having a plurality of pixels including a touch sensor circuit that generates a photo current differently depending on whether a pixel circuit and a touch are formed at each intersection of gate lines and data lines; A backlight having a plurality of light sources sequentially illuminating the back of the liquid crystal display panel with light that is turned on for a first period and turned off for a second period following the first period; A timing controller generating a backlight control signal for sequentially blinking the light sources; A readout integrated circuit converting a photocurrent generated by the scan driving of the touch sensor circuit into photosensitive data; A touch for generating the touch location information in which the light sensing data is generated and separated during the first period and generated during the second period, and extracting a difference value of the separated and stored light sensing data to exclude the influence of external light. Position information detection circuit; And a system for performing a processor process for touch recognition by applying the touch location information to a touch recognition algorithm.

The backlight control signal includes a plurality of control signals for respectively controlling the blinking of the light sources; Each of the control signals includes a lighting control signal and a lighting control signal.

The touch position information detecting circuit may include a lighting scan storage unit configured to store light sensing data supplied from the readout integrated circuit during the first period synchronized with the lighting control signal; An unlit scan storage unit for storing optical sensing data supplied from the readout integrated circuit during the second period synchronized with the unlit control signal; And a difference value extraction unit for comparing the light sensing data from the lit scan storage unit and the unlit scan storage unit one-to-one, and extracting a difference value of the compared data as a result.

The control signals are sequentially generated with a constant phase shift value.

According to an exemplary embodiment of the present invention, a method of driving a liquid crystal display device having a liquid crystal display panel including a pixel circuit and a touch sensor circuit that generates a photo current differently depending on whether or not a touch is performed for each pixel is performed by time-dividing one frame period sequentially. Generating a first and a second gate start pulse; Displaying normal data RGB during a first period synchronized with the first gate start pulse and displaying black data BD on the liquid crystal display panel during a second period synchronized with the second gate start pulse; Converting a photocurrent from the touch sensor circuit into photosensitive data; Separately storing the photosensitive data generated during the first period and generated during the second period, and extracting a difference value of the separated and stored photosensitive data to generate touch location information without the influence of external light. ; And performing a processor process for touch recognition by applying the touch location information to a touch recognition algorithm.

According to another embodiment of the present invention, a liquid crystal display panel including a touch sensor circuit for generating a photo current differently according to whether a pixel circuit and a touch is performed for each pixel, and a plurality of light sources irradiating light to the rear surface of the liquid crystal display panel. A driving method of a liquid crystal display device having a backlight may include sequentially generating a backlight control signal including a lighting control signal and a lighting control signal with a constant phase shift value; Turning on the light sources for a first period synchronized with the lighting control signal and turning off the light sources for a second period synchronized with the extinction control signal; Converting a photocurrent from the touch sensor circuit into photosensitive data; Separately storing the photosensitive data generated during the first period and generated during the second period, and extracting a difference value of the separated and stored photosensitive data to generate touch location information without the influence of external light. ; And performing a processor process for touch recognition by applying the touch location information to a touch recognition algorithm.

The liquid crystal display and the driving method thereof according to the present invention can simplify the touch recognition algorithm and can greatly increase the reliability of the touch recognition.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 4 to 12.

4 is a block diagram illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 4, in the liquid crystal display according to the exemplary embodiment of the present invention, 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 On the liquid crystal display panel 10 and the data lines D1 to Dm where VLn intersects, pixels P having touch sensor circuits are disposed at the intersections thereof, and the pulses are impulse driven by the black data BD insertion method. A data driving circuit 20 for supplying a data voltage, a gate driving circuit 30 for supplying scan pulses to the gate lines G1 to Gn, a data driving circuit 20 and a gate driving circuit 30 A timing controller 40 for controlling the driving timing of the driving circuit; a driving voltage supply circuit 50 for supplying driving voltages required for driving the touch sensor circuit to the driving voltage supply lines VL1 to VLn; Back light unit 6 for irradiating light to the back of 10 0), a readout integrated circuit 70 for converting the photocurrent from the touch sensor circuit into the light sensing data LSdata, and first and second gate start pulses generated from the timing controller 40 for impulse driving. A touch position information detection circuit 80 for generating touch position information XY in which the influence of external light is excluded by using the light sensing data LSdata from the GSP1 and GSP2 and the readout integrated circuit 70, and the touch position A system 90 is applied to apply information XY to a touch recognition algorithm to perform a processor process for touch recognition.

The liquid crystal display panel 10 includes an upper substrate including a color filter, a lower substrate on which pixels P 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. .

On the lower substrate of the liquid crystal display panel 10, a plurality of data lines D1 to Dm and a plurality of gate lines G0 to Gn are orthogonal to each other, and a plurality of parallel lines are parallel to the gate lines G0 to Gn. A plurality of readout lines ROL1 to ROLm orthogonal to the driving voltage supply lines VL1 to VLn, the gate lines G0 to Gn, and the driving voltage supply lines VL1 to VLn are formed. The pixel circuit P1 including the pixel TFT TFT1, the liquid crystal cells Clc, and the storage capacitor Cst1 as shown in FIG. 8 at the intersection of the data lines D1 to Dm and the gate lines G1 to Gn. ) Is formed, and at the intersection of the driving voltage supply lines VL1 to VLn and the lead-out lines ROL1 to ROLm, the sensor TFT S-TFT, the sensor capacitor Cst2 and the switch TFT ( The touch sensor circuit P2 including the TFT2 is formed. Each of the driving voltage supply lines VL1 to VLn includes a supply line for supplying a high potential driving voltage to the touch sensor circuit P2, and a supply line for supplying a bias voltage to the touch sensor circuit P2. The touch sensor circuit P2 generates a photo current differently depending on whether an opaque object (hereinafter referred to as a "finger") of a finger or the like is touched, and the photo current is generated through the readout integrated circuits ROL1 to ROLm. 70).

A black matrix is formed on the upper substrate of the liquid crystal display panel 10 to cover the boundary between the pixels P. 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 vertical electric field modes such as twisted nematc (TN) mode and vertical alignment (VA) mode, and in plane switching (IPS). In a horizontal electric field mode such as a mode and a fringe field switching (FFS) mode, the substrate is formed on the lower substrate.

The data driving circuit 20 receives the normal data RGB and the black data BD from the gamma reference voltage generator (not shown) in response to the data control signal DDC from the timing controller 40. The analog gamma compensation voltage is converted based on the GMA, and the analog gamma compensation voltage is supplied to the data lines D1 to Dm of the liquid crystal display panel 10 as a data voltage.

The gate driving circuit 30 generates a scan pulse in response to the gate control signal GDC from the timing controller 40, and sequentially supplies the scan pulses to the gate lines G1 to Gn to supply a data voltage. The horizontal line of the liquid crystal display panel 10 is selected.

The timing controller 40 generates black data BD for driving an impulse, and rearranges the black data BD and the normal data RGB from the system 90 to match the liquid crystal display panel 10. It supplies to the furnace 20. In addition, the timing controller 40 uses the timing control signals Vsync, Hsync, DCLK, and DE from the system 90 to control the data driving circuit 20 and the gate driving circuit. The gate control signal GDC for controlling the furnace 30 is generated.

The data control signal DDC includes a source sampling clock (SSC) and a data driving circuit for instructing a latch operation of data in the data driving circuit 20 based on a rising or falling edge. A source output enable signal SOE indicating the output of the signal 20 and a polarity control signal POL indicating the polarity of the data voltage to be supplied to the liquid crystal cells Clc of the liquid crystal display panel 10. .

The gate control signal GDC is input to a gate start pulse (GSP) and a shift register in the gate driving circuit 30 indicating a start horizontal line at which a scan is started during one frame period in which one screen is displayed, A gate shift clock signal (GSC) generated by a pulse width corresponding to an ON period of the pixel TFT as a timing control signal for sequentially shifting the start pulse GSP, and the gate driving circuit 30. A gate output enable signal (GOE) indicating the output of the signal. As shown in FIG. 5, the gate start pulse GSP includes the first gate start pulse GSP1 indicating the scan start horizontal line of the normal data RGB in one frame period, and the black data BD. And a second gate start pulse GSP2 indicating a scan start horizontal line.

The driving voltage supply circuit 50 generates a high potential driving voltage and a bias voltage necessary for driving the touch sensor circuit P2 and supplies them to the driving voltage supply lines VL1 to VLn.

The backlight unit 60 includes a plurality of lamps installed to overlap the liquid crystal display panel 116 on the rear surface of the liquid crystal display panel 10. The lamp used in the backlight unit 60 may be any one of a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and a heat cathode fluorescent lamp (HCFL). Can be. The lamps irradiate light onto the rear surface of the liquid crystal display panel 10 by driving an inverter (not shown). Meanwhile, the backlight unit 60 may include a plurality of light emitting diodes instead of or with the lamps.

The lead-out integrated circuit 70 includes a plurality of circuits connected to the lead-out lines ROL1 to RLOm of the liquid crystal display panel 10, respectively. The light is converted into the photosensitive sensing data LSdata and supplied to the touch position information detecting circuit 80.

The touch position information detection circuit 80 may include the first and second gate start pulses GSP1 and GSP2 generated from the timing controller 40 and the optical sensing data LSdata from the readout integrated circuit 70 for impulse driving. Using to generate the touch position information (XY) is excluded the influence of the external light. To this end, the touch position information detecting circuit 80 includes an RGB scan storage 82, a BD scan storage 84, and a difference value extraction section 86 as shown in FIG.

The RGB scan storage unit 82 stores the light sensing data LSdata supplied from the readout integrated circuit 70 during the first period T1 synchronized with the first gate start pulse GSP1 as shown in FIG. 5. . Information stored in the RGB scan storage 82 is as shown in FIG. 7A. In FIG. 7A, "A" indicates information about a touch point by a finger, "B" indicates information about a part where external light is blocked by a finger, and "C" indicates information about a part exposed to external light. Represent each.

The BD scan storage unit 84 stores the light sensing data LSdata supplied from the readout integrated circuit 70 during the second period T2 synchronized with the second gate start pulse GSP2 as shown in FIG. 5. . The information stored in the BD scan storage 84 is shown in FIG. 7B. In Fig. 7B, "B" represents information on the portion where external light is blocked by the finger, and "C" represents information on the portion exposed to the external light.

The difference value extraction unit 86 compares the light sensing data from the RGB scan storage unit 82 and the BD scan storage unit one-to-one, and as a result, extracts the difference value of the compared data, thereby removing the influence of external light. Generate position information XY. The extracted difference value information includes only information A about a touch point by a finger as shown in FIG. 7C.

Meanwhile, in the touch location information detecting circuit 80, two memories 82 and 84 may be integrated into one memory to cope with the reduction in the number of memories. Using this integrated memory, the touch position information detecting circuit 80 first stores the light sensing data LSdata supplied from the readout integrated circuit 70 during the first period T1, and then stores the stored light sensing data LSdata. The optical sensing data LSdata supplied from the readout integrated circuit 70 is subtracted from the data LSdata for the second period T2, and the difference value is added to the optical sensing data LSdata stored for the first period T1. You can overwrite it.

The system 90 converts analog image data from an external source supplied through an interface circuit (not shown) into digital normal data RGB and supplies the same to the timing controller 40. The system 90 extracts the composite video signal using the image data from the interface circuit, and uses the extracted composite video signal to match the resolution of the liquid crystal display panel 10 (HV sync) and the data enable signal. DE and the dot clock DCLK are generated and supplied to the timing controller 40.

In particular, the system 90 includes the touch algorithm processing unit 92 to apply the touch position information XY supplied from the touch position information detection circuit 80 to the touch recognition algorithm, thereby performing a processor process for touch recognition. The result is reflected on the liquid crystal display panel 10 again. As described above, since the touch position information XY includes only information on the touch point by the finger, the touch recognition algorithm embedded in the touch algorithm processing unit 92 may be greatly simplified as compared with the related art. In addition, since only the information on the touch point by the finger is included in the touch position information XY, the reliability of the touch recognition may be greatly improved.

FIG. 8 is an equivalent circuit diagram of the pixel P shown in FIG. 4.

Referring to FIG. 8, the pixel P includes the pixel circuit P1 formed at the intersection of the j-th gate line Gj and the j-th data line Dj, the j-th first supply line VLja, and j. The touch sensor circuit P2 is formed at an intersection of the second second supply line VLjb and the jth lead-out 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. 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 storage capacitor Cst1 is connected between the drain electrode of the pixel TFT TFT1 and the second supply line VLjb.

The touch sensor circuit P2 is a sensor TFT (S-TFT) that generates a photocurrent i differently depending on whether it corresponds to a touch point during a period in which a driving voltage is supplied, and a sensor that stores charges by the photocurrent i. A capacitor Cst2 and a switch TFT TFT2 for switching the charges stored in the sensor capacitor Cst2 to the readout line ROLj.

The gate electrode of the sensor TFT (S-TFT) is connected to the second supply line VLjb, the source electrode is connected to the first supply line VLja, and the drain electrode is connected to the first node N1. The bias voltage Vbias set to a voltage below its threshold voltage is supplied to the gate electrode of the sensor TFT (S-TFT), and the driving voltage is supplied to the source electrode of the sensor TFT (S-TFT). 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 photocurrent during the period in which the driving voltage is supplied in response to light incident from the outside is applied. i), but a photocurrent i of a different size is generated depending on whether the touch point is present. In other words, the sensor TFT (S-TFT) generates a large photocurrent i when corresponding to the touch point in the illumination environment (indoor environment) that is darker than the backlight, whereas it produces a brighter illumination environment than the backlight. In the (outdoor environment), a small photocurrent i is generated when corresponding to the touch point compared to when not corresponding to the touch point.

Charges by the photocurrent i are stored in the sensor capacitor Cst2 connected between the first node N1 and the second supply line VLjb. The voltage VN1 of the first node is gradually increased by the charges stored in the sensor capacitor Cst2 until the switch TFT TFT2 is turned on. The voltage VN1 of the first node has a different size depending on whether it corresponds to the touch point during the period in which the driving voltage is supplied. In other words, the voltage VN1 of the first node has a larger value when corresponding to the touch point than when not corresponding to the touch point in an illuminance environment (indoor environment) that is darker than the backlight, and is brighter than the backlight (outdoor environment). ) Has a smaller value when corresponding to a touch point than when not corresponding to a touch point.

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 lead out line ROLj. 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, so that the first node voltage VN1 is used as the light sensing signal. )

9 is a block diagram illustrating a liquid crystal display according to another exemplary embodiment of the present invention.

9, a liquid crystal display according to another exemplary embodiment of the present invention includes a plurality of gate lines G0 through Gn, a plurality of data lines D1 through Dm, and a plurality of driving voltage supply lines VL1 through. The liquid crystal display panel 110 in which the pixels P having the touch sensor circuit are disposed at the intersections of the VLn and the data driving circuit 120 for supplying the data voltage to the data lines D1 to Dm. And a gate driving circuit 130 for supplying scan pulses to the gate lines G1 to Gn, and a timing controller 140 for controlling driving timings of the data driving circuit 120 and the gate driving circuit 130. And a driving voltage supply circuit 150 for supplying a driving voltage required for driving the touch sensor circuit to the driving voltage supply lines VL1 to VLn, and light flashing sequentially on the rear surface of the liquid crystal display panel 110. Backlight unit 160 and a touch sensor circuit A readout integrated circuit 170 for converting the photocurrent from the photosensitive data into the light sensing data LSdata, and a photodetection signal from the backlight control signal SBL and the readout integrated circuit 170 from the timing controller 140 for impulse driving. Touch location information detection circuit 180 for generating touch location information XY without influence of external light using data LSdata and touch location information XY for a touch recognition algorithm. A system 190 for performing a processor process is provided.

Since the liquid crystal display panel 110 and the driving voltage supply circuit 150 are substantially the same as the liquid crystal display panel 10 and the driving voltage supply circuit 50 shown in FIG. 4, detailed description thereof will be omitted. .

The data driving circuit 120 based on the gamma reference voltages GMA from the gamma reference voltage generator (not shown) in response to the data control signal DDC from the timing controller 140. The analog gamma compensation voltage is converted to the 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 110 as a data voltage.

The gate driving circuit 130 generates a scan pulse in response to the gate control signal GDC from the timing controller 140, and sequentially supplies the scan pulses to the gate lines G1 to Gn to supply a data voltage. The horizontal line of the liquid crystal display panel 110 is selected.

The timing controller 140 realigns the digital video data RGB input from the system 190 to the liquid crystal display panel 110 and supplies the digital video data RGB to the data driving circuit 120. In addition, the timing controller 140 uses the timing control signals Vsync, Hsync, DCLK, and DE from the system 190 to control the data driving circuit 120 and the gate driving circuit. A gate control signal GDC for controlling the furnace 130 and a backlight control signal SBL for controlling the backlight are generated.

The data control signal DDC includes a source sampling clock (SSC) and a data driving circuit for instructing a latch operation of data in the data driving circuit 120 based on a rising or falling edge. A source output enable signal SOE indicating the output of the 120 and a polarity control signal POL indicating the polarity of the data voltage to be supplied to the liquid crystal cells Clc of the liquid crystal display panel 110. .

The gate control signal GDC is input to a gate start pulse (GSP) and a shift register in the gate driving circuit 130 indicating a start horizontal line at which a scan starts in one frame period during which one screen is displayed, and the gate A gate shift clock signal (GSC) generated by a pulse width corresponding to an ON period of the pixel TFT as a timing control signal for sequentially shifting the start pulse GSP, and the gate driving circuit 130. A gate output enable signal (GOE) indicating the output of the signal.

The backlight control signal SBL includes a plurality of control signals SBL1 to SBLk corresponding to the plurality of lamps L1 to Lk as shown in FIGS. 10 and 11. Each of the control signals SBL1 to SBLk corresponds to a lighting control signal BLon generated at a high logic level in response to the first period T1 during which the lamp is turned on, and to a second period T2 at which the lamp is turned off. And an unlit control signal BLoff generated at a low logic level. These control signals SBL1 to SBLk are sequentially generated with a constant phase shift value and then supplied to a plurality of inverters I1 to Ik connected to the lamps L1 to Lk one-to-one to implement impulse driving.

The backlight unit 160 includes a plurality of lamps installed to overlap the liquid crystal display panel 116 on the rear surface of the liquid crystal display panel 110. The lamp used for the backlight unit 160 may be any one of a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and a heat cathode fluorescent lamp (HCFL). . The lamps irradiate the back of the liquid crystal display panel 110 with light that is sequentially blinking in response to the backlight control signal SBL from the timing controller 140. Meanwhile, the backlight unit 160 may include a plurality of light emitting diodes instead of or in combination with the lamps.

The lead-out integrated circuit 170 includes a plurality of circuits connected to the lead-out lines ROL1 to RLOm of the liquid crystal display panel 110, respectively. The image data is converted into the photosensitive sensing data LSdata and supplied to the touch position information detecting circuit 180.

The touch position information detecting circuit 180 eliminates the influence of external light by using the backlight control signal SBL from the timing controller 140 and the light sensing data LSdata from the readout integrated circuit 170 to drive the impulse. Generated touch position information XY. To this end, the touch position information detecting circuit 180 includes a lit scan storage unit 182, an unlit scan storage unit 184, and a difference value extraction unit 186 as shown in FIG. 12.

The lighting scan storage unit 182 stores the light sensing data LSdata supplied from the readout integrated circuit 170 during the first period T1 synchronized with the lighting control signal BLon of FIG. 11. Information stored in the lighting scan storage unit 182 is as shown in FIG. 7A. In FIG. 7A, "A" indicates information about a touch point by a finger, "B" indicates information about a part where external light is blocked by a finger, and "C" indicates information about a part exposed to external light. Represent each.

The unlit scan storage unit 184 stores the light sensing data LSdata supplied from the readout integrated circuit 170 during the second period T2 synchronized with the unlit control signal BLoff as shown in FIG. 11. The information stored in the light-off scan storage unit 184 is as shown in FIG. 7B. In Fig. 7B, "B" represents information on the portion where external light is blocked by the finger, and "C" represents information on the portion exposed to the external light.

The difference value extraction unit 186 compares the light sensing data from the lit scan storage unit 182 and the unlit scan storage unit 184 one-to-one, and extracts the difference value of the compared data as a result, thereby removing the influence of external light. Generate position information XY. The extracted difference value information includes only information A about a touch point by a finger as shown in FIG. 7C.

Meanwhile, in the touch location information detecting circuit 180, two memories 182 and 184 may be integrated into one memory in order to reduce the number of memories. Using this integrated memory, the touch position information detecting circuit 180 first stores the light sensing data LSdata supplied from the readout integrated circuit 170 for the first period T1 and then stores the stored light sensing data LSdata. The light sensing data LSdata supplied from the readout integrated circuit 170 is subtracted from the data LSdata for the second period T2, and the difference value is stored in the light sensing data LSdata stored for the first period T1. You can overwrite it.

The system 190 converts analog image data from an external source supplied through an interface circuit (not shown) into digital normal data RGB and supplies the same to the timing controller 140. The system 190 extracts the composite video signal using the image data from the interface circuit, and uses the extracted composite video signal to synchronize the HV sync and the data enable signal according to the resolution of the liquid crystal display panel 110. DE and the dot clock DCLK are generated and supplied to the timing controller 140.

In particular, the system 190 includes the touch algorithm processing unit 192 to apply the touch position information XY supplied from the touch position information detecting circuit 180 to the touch recognition algorithm, thereby performing a processor process for touch recognition. The result is reflected on the liquid crystal display panel 110 again. As described above, since the touch position information XY includes only information on a touch point by a finger from which the influence of external light is excluded, the touch recognition algorithm embedded in the touch algorithm processing unit 192 can be greatly simplified as compared with the related art. have. In addition, since the touch position information XY includes only information on the touch point by the finger from which the influence of external light is excluded, the reliability of the touch recognition may be greatly improved.

As described above, the LCD and the driving method thereof according to the present invention can simplify the algorithm of the touch recognition and can greatly increase the reliability of the touch recognition.

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.

FIG. 3 is a view illustrating a result of sensing a touched portion in a conventional touch panel, a cell type liquid crystal display device; FIG.

4 is a block diagram illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

5 is a timing diagram of first and second gate start pulses for implementing impulse driving through black data insertion.

FIG. 6 is a detailed configuration diagram of the touch position information detection circuit shown in FIG. 4.

FIG. 7A illustrates information stored in the RGB scan storage of FIG. 6 or the lit scan storage of FIG. 12.

FIG. 7B illustrates information stored in the BD scan storage of FIG. 6 or the unlit scan storage of FIG. 12.

FIG. 7C is a diagram illustrating information stored in a difference value extraction unit of FIG. 6 or FIG. 12. FIG.

8 is an equivalent circuit diagram of the pixel shown in FIG. 4;

9 is a block diagram illustrating a liquid crystal display according to another exemplary embodiment of the present invention.

10 is a detailed block diagram of the backlight unit of FIG. 9;

11 is a timing diagram of a plurality of control signals included in a backlight control signal.

12 is a detailed configuration diagram of the touch position information detection circuit shown in FIG. 9;

<Description of Symbols for Main Parts of Drawings>

10,110 liquid crystal display panel 20,120 data driving circuit

30,130: Gate driving circuit 40,140: Timing controller

50,150: driving voltage supply circuit 60,160: backlight unit

70,170: readout integrated circuit 80,180: touch location information detection circuit

82: RGB scan storage 84: BD scan storage

86,186: difference value extraction unit 182: lit scan storage unit

184: light off scan storage 90,190: system

92,192: Touch algorithm processing unit

Claims (9)

Each pixel has a plurality of pixels including a touch sensor circuit that generates a photo current differently depending on whether a pixel circuit and a touch are present at each intersection of the gate lines and the data lines, and displays normal data RGB during a first period, and displays the first period. A liquid crystal display panel displaying black data BD for a second period following the second period; A timing controller configured to generate first and second gate start pulses corresponding to the first and second periods, respectively; A readout integrated circuit for converting a photocurrent from the touch sensor circuit into photosensitive data; A touch for generating the touch location information in which the light sensing data is generated and separated during the first period and generated during the second period, and extracting a difference value of the separated and stored light sensing data to exclude the influence of external light. Position information detection circuit; And And a system for performing a processor process for touch recognition by applying the touch position information to a touch recognition algorithm. The method of claim 1, The touch position information detection circuit, An RGB scan storage unit for storing optical sensing data supplied from the readout integrated circuit during the first period synchronized with the first gate start pulse; A BD scan storage unit for storing optical sensing data supplied from the readout integrated circuit during the second period synchronized with the second gate start pulse; And And a difference value extraction unit for comparing the light sensing data from the RGB scan storage unit and the BD scan storage unit one-to-one, and extracting the difference value of the compared data as a result. The method of claim 1, And the first and second gate start pulses are sequentially generated by time division of one frame period. A liquid crystal display panel having a plurality of pixels including a touch sensor circuit that generates a photo current differently depending on whether a pixel circuit and a touch are formed at each crossing region of the gate lines and the data lines; A backlight having a plurality of light sources sequentially illuminating the back of the liquid crystal display panel with light that is turned on for a first period and turned off for a second period following the first period; A timing controller generating a backlight control signal for sequentially blinking the light sources; A readout integrated circuit converting a photocurrent generated by the scan driving of the touch sensor circuit into photosensitive data; A touch for generating the touch location information in which the light sensing data is generated and separated during the first period and generated during the second period, and extracting a difference value of the separated and stored light sensing data to exclude the influence of external light. Position information detection circuit; And And a system for performing a processor process for touch recognition by applying the touch position information to a touch recognition algorithm. The method of claim 4, wherein The backlight control signal includes a plurality of control signals for respectively controlling the blinking of the light sources; And each of the control signals includes a lighting control signal and a lighting control signal. The method of claim 5, wherein The touch position information detection circuit, A lighting scan storage unit for storing the light sensing data supplied from the readout integrated circuit during the first period synchronized with the lighting control signal; An unlit scan storage unit for storing optical sensing data supplied from the readout integrated circuit during the second period synchronized with the unlit control signal; And And a difference value extraction unit for comparing light-sensing data from the lit scan storage unit and the unlit scan storage unit one-to-one, and extracting a difference value of the compared data as a result. The method of claim 5, wherein And the control signals are sequentially generated with a constant phase shift value. In the driving method of a liquid crystal display device having a liquid crystal display panel including a touch sensor circuit for generating a photo current differently depending on whether the pixel circuit and the touch for each pixel, Time-dividing one frame period to sequentially generate first and second gate start pulses; Displaying normal data RGB during a first period synchronized with the first gate start pulse and displaying black data BD on the liquid crystal display panel during a second period synchronized with the second gate start pulse; Converting a photocurrent from the touch sensor circuit into photosensitive data; Separately storing the photosensitive data generated during the first period and generated during the second period, and extracting a difference value of the separated and stored photosensitive data to generate touch location information without the influence of external light. ; And And performing a processor process for touch recognition by applying the touch position information to a touch recognition algorithm. Driving of a liquid crystal display having a liquid crystal display panel including a pixel circuit and a touch sensor circuit for generating a photo current differently depending on whether the pixel is touched for each pixel, and a backlight including a plurality of light sources irradiating light to the rear surface of the liquid crystal display panel. In the method, Sequentially generating a backlight control signal including a lighting control signal and a lighting control signal with a constant phase shift value; Turning on the light sources for a first period synchronized with the lighting control signal and turning off the light sources for a second period synchronized with the extinction control signal; Converting a photocurrent from the touch sensor circuit into photosensitive data; Separately storing the photosensitive data generated during the first period and generated during the second period, and extracting a difference value of the separated and stored photosensitive data to generate touch location information without the influence of external light. ; And And performing a processor process for touch recognition by applying the touch position information to a touch recognition algorithm.

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