KR20120111674A - Display having touch sensor and driving method thereof - Google Patents

Abstract

The present invention relates to a display device having a touch sensor and a driving method thereof, the display device comprising: touch sensors; A touch sensor driving circuit which outputs the touch sensor driving pulses two or more times through each of the output channels during the touch sensor driving period, and repeatedly supplies the touch sensor driving pulses to each of the Tx lines connected to the touch sensors two or more times; A touch sensor reading circuit for repeatedly sampling and amplifying the output of each of the touch sensors two or more times through Rx lines connected to the touch sensors during the touch sensor driving period and converting the amplified data into digital touch data; And storing, in memory, the digital touch data obtained from each of the touch sensors at least two times during the touch sensor driving period, and adding, subtracting, and averaging the digital touch data repeatedly output from each of the touch sensors. It includes a touch controller to implement.

Description

DISPLAY HAVING TOUCH SENSOR AND DRIVING METHOD THEREOF}

The present invention relates to a display device having a touch sensor and a driving method thereof.

With the trend toward lighter and slimmer home appliances and portable information devices, user input means are being replaced by touch sensors in button-type switches. The touch screen applied to the display device includes a plurality of touch sensors. The touch sensors may be embedded in an in-cell type in the display panel. Hereinafter, a display device in which touch sensors are embedded in the display panel will be referred to as a display device with a touch sensor.

The capacitive touch sensors may be implemented in a mutual capacitance method. The capacitive touch sensors include mutual capacitance Cm formed at the intersections of the signal lines Tx and Rx that cross each other as shown in FIG. 1A. When a finger approaches the mutual capacitance Cm of the touch sensor as shown in FIG. 1B, the electric field between the electrodes is blocked, thereby lowering the charge amount of the mutual capacitance Cm. Therefore, the capacitive touch sensors can recognize the touch by measuring a change in the charge amount of the mutual capacitance Cm before and after the touch.

As shown in FIGS. 2A and 2B, the output RO of the touch sensor is compared with a preset reference value REF and recognized as an output of the touch sensor approached by a finger when the reference value REF is greater than or equal to the reference value REF. In the display device with a built-in touch sensor, the output RO of the touch sensor may be affected by a driving voltage or a touch reference voltage of the display panel through parasitic capacitance in the display panel. For example, the ideal output RO of the touch sensor is shown in FIG. 2A, but the output RO of the touch sensor is unstable analog of FIG. 2B due to the influence of the signal voltage supplied through the wires connected to the pixels. Appear in the output.

3 illustrates an example in which the output of the touch sensor is changed when the common voltage Vcom or the touch reference voltage Vref supplied to the pixels of the display panel is changed. In FIG. 3, reference numerals '21' and '22' denote outputs of touch sensors actually touched. The first touch sensor output 21 may be recognized as the output of the touch sensor actually touched when the common voltage Vcom or the reference voltage Vref does not change, but the second touch sensor output 22 may be a common voltage ( Vcom) or the voltage is lowered by the change of the reference voltage (Vref) can be mistaken for the output of the touch sensor that is not touched.

4 illustrates an example in which the output of the touch sensor is changed when the ground voltage GND of the driving circuits of the display panel is changed. In FIG. 4, reference numerals 23 and 24 denote outputs of touch sensors that are not touched. The third touch sensor output 23 may be recognized as an output of a touch sensor that is not actually touched when the ground voltage GND does not change, whereas the fourth touch sensor output 24 changes in the ground voltage GND. Affected by the voltage, the voltage can be increased to be mistaken as the output of the touch sensor.

The present invention provides a display device having a touch sensor and a driving method thereof capable of increasing the sensitivity, touch recognition rate, and reliability of output data of the touch sensor.

The display device of the present invention is a touch sensor; A touch sensor driving circuit which outputs the touch sensor driving pulses two or more times through each of the output channels during the touch sensor driving period, and repeatedly supplies the touch sensor driving pulses to each of the Tx lines connected to the touch sensors two or more times; A touch sensor reading circuit for repeatedly sampling and amplifying the output of each of the touch sensors two or more times through Rx lines connected to the touch sensors during the touch sensor driving period and converting the amplified data into digital touch data; And storing, in memory, the digital touch data obtained from each of the touch sensors at least two times during the touch sensor driving period, and adding, subtracting, and averaging the digital touch data repeatedly output from each of the touch sensors. It includes a touch controller to implement.

The touch controller calculates a plurality of digital touch data obtained from the same touch sensor.

The touch sensors are formed on a display panel. The display panel further includes data lines for supplying a data voltage to the pixels and gate lines for supplying scan pulses to the pixels. The Tx lines and the Rx lines cross each other and mutual capacitances are formed at the intersection thereof.

The display device may further include a display data driving circuit configured to supply an analog video dayton voltage to the data lines during a display period; A display scan driving circuit for sequentially supplying scan pulses synchronized with the analog video data voltage to the gate lines during the display period; And time-dividing one frame period into the display period and the touch sensor driving period to control operation timings of the display data driving circuit and the display scan driving circuit during the display period, and the touch sensor driving circuit during the touch sensor driving period. And a timing controller controlling an operation timing of the touch sensor read circuit.

The touch controller removes noise of an output signal obtained from the touch sensor by adding a plurality of digital touch data obtained from the same touch sensor.

The touch controller removes noise of an output signal obtained from the touch sensor by subtracting a plurality of digital touch data obtained from the same touch sensor.

The touch controller removes noise of an output signal obtained from the touch sensor by averaging a plurality of digital touch data obtained from the same touch sensor.

The touch controller averages a plurality of digital touch data obtained from the same touch sensor. The touch controller removes noise of an output signal obtained from the touch sensor by excluding digital touch data having the largest difference from the average calculation result and selecting digital touch data having the largest value among the remaining digital touch data.

The driving method of the display device may include repeatedly supplying a touch sensor driving pulse to the Tx lines connected to the touch sensors two or more times during the touch sensor driving period; Repeatedly sampling and amplifying the output of each of the touch sensors two or more times via Rx lines connected to the touch sensors during the touch sensor driving period and converting the digital touch data into digital touch data; And storing, in memory, the digital touch data obtained from each of the touch sensors at least two times during the touch sensor driving period, and adding, subtracting, and averaging the digital touch data repeatedly output from each of the touch sensors. Performing the steps.

The present invention repeatedly samples the output of the touch sensors within one touch sensor driving period, and adds, subtracts or averages data obtained from the same touch sensor to remove noise components. As a result, the present invention can improve the sensitivity of the touch sensors, the touch recognition rate and the reliability of the output data of the touch sensor.

1A and 1B are diagrams illustrating operations before and after touch of capacitive touch sensors.
2A and 2B are waveform diagrams showing an output and a reference value of a touch sensor.
3 and 4 are waveform diagrams showing an example of misunderstanding of touch sensors.
5 is a block diagram illustrating a display device according to an exemplary embodiment of the present invention.
FIG. 6 is an equivalent circuit diagram illustrating a part of a pixel array and touch sensors included in the display panel of FIG. 5.
FIG. 7 is a plan view illustrating a part of a pixel array and touch sensors included in the display panel of FIG. 5.
8 is a waveform diagram illustrating a method of driving the display device illustrated in FIG. 5.
FIG. 9 is a circuit diagram showing in detail the touch sensor reading circuit shown in FIG. 5.
FIG. 10 is a waveform diagram illustrating a timing control signal of the touch sensor read circuit illustrated in FIG. 5.
FIG. 11 is a timing diagram illustrating display timing control signals generated in a display period and touch sensor timing signals generated in a touch sensor driving period.
12 is a flowchart illustrating step by step a control procedure of a method of driving the display device illustrated in FIG. 5.
13 is a waveform diagram illustrating a noise removing method according to a first embodiment of the present invention.
14 is a waveform diagram illustrating a noise removing method according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, when it is determined that a detailed description of known functions or configurations related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The display device of the present invention is a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an organic light emitting diode display (Organic Light Emitting Display) , OLED), electrophoretic display (EPD), and the like, and touch sensors embedded in an in-cell type in the display panel of the flat display device. In the following embodiments, as an example of a flat panel display element, a liquid crystal display element is described, but it should be noted that the display device of the present invention is not limited to the liquid crystal display element.

Referring to FIG. 5, a display device according to an exemplary embodiment of the present invention may include a display panel 100, a display data driver circuit 202, a display scan driver circuit 204, a touch sensor driver circuit 302, and a touch sensor readout. A touch sensor read-out circuit 304, a touch controller 306, a timing controller 104, and the like.

In the display panel 100, a liquid crystal layer is formed between two glass substrates. The lower substrate of the display panel 100 includes a plurality of data lines D1 to Dm and m is a positive integer, and a plurality of gate lines G1 to Gn intersecting the data lines D1 to Dm are positive. ), A plurality of TFTs (Thin Film Transistor, TFT of FIG. 6) and liquid crystal cells (Clc of FIG. 6) formed at intersections of the data lines D1 to Dm and the gate lines G1 to Gn. ) Includes a plurality of pixel electrodes 11 for charging the data voltages, storage capacitors (Cst of FIG. 6), touch sensors, etc., connected to the pixel electrodes 11 to maintain the voltage of the liquid crystal cell. do.

6 and 7, the touch sensors intersect the Tx lines (T1 to Tj, j is a positive integer smaller than n) and the Tx lines (T1 to Tj) parallel to the gate lines G1 to Gn. Rx lines (R1 to Ri, i is a positive integer less than m) parallel to the data lines D1 to Dm, and at the intersection of the Tx lines T1 to Tj and Rx lines R1 to Ri Formed mutual capacitances (Cm) and the like.

The Tx lines T1 to Tj and the Rx lines R1 to Ri are connected to the common electrode 12 to apply a common voltage Vcom to the common electrode 12 during a preset display period (DIS in FIG. 8). Supply. During the preset touch sensor driving period (TS of FIG. 8), the touch sensor driving pulses for driving the touch sensor are supplied to the Tx lines T1 to Tj, and the touch reference voltages are supplied to the Rx lines R1 to Ri. Vref) is supplied.

The pixels of the display panel 100 are formed in a pixel area defined by the data lines D1 to Dm and the gate lines G1 to Gn, and are arranged in a matrix form. The liquid crystal cell of each pixel is driven by an electric field applied according to the voltage difference between the data voltage applied to the pixel electrode 11 and the common voltage Vcom applied to the common electrode 12 to adjust the amount of incident light transmitted. . The TFTs are turned on in response to the gate pulses from the gate lines G1 to Gn to supply the voltage from the data lines D1 to Dm to the pixel electrode 11 of the liquid crystal cell.

The upper substrate of the display panel 100 may include a black matrix, a color filter, and the like. The lower glass substrate of the display panel 100 may be implemented with a color filter on TFT (COT) structure. In this case, the black matrix and the color filter may be formed on the lower glass substrate of the display panel 100.

The common electrode 12 is formed on the upper glass substrate in a vertical electric field driving method such as twisted nematic (TN) mode and vertical alignment (VA) mode, and is similar to an in plane switching (IPS) mode and a fringe field switching (FFS) mode. In the horizontal electric field driving method, the pixel electrode 11 is formed on the lower substrate. The common voltage Vcom supplied to the common electrode 12 may be a DC voltage between 7V and 8V. The common electrode 12 is connected to at least one of the Tx lines T1 to Tj and the Rx lines R1 to Ri, and is common through the Tx lines T1 to Tj and the Rx lines R1 to Ri. The voltage Vcom can be supplied.

Polarizing plates are attached to each of the upper and lower substrates of the display panel 100, and an alignment layer for setting the pretilt angle of the liquid crystal is formed on an inner surface of the display panel 100 in contact with the liquid crystal. A column spacer may be formed between the upper substrate and the lower substrate of the display panel 100 to maintain a cell gap of the liquid crystal cell.

The display data driving circuit 202 includes a plurality of source drive integrated circuits (ICs). The source drive ICs latch the digital video data RGB input from the timing controller 104 during the display period DIS. The source drive ICs convert the digital video data RGB into analog positive / negative gamma compensation voltages during the display period DIS to output analog video data voltages. The analog video data voltage is supplied to the data lines D1 to Dm.

The display scan driver circuit 204 includes one or more scan drive ICs. The scan drive IC sequentially supplies scan pulses (or gate pulses) synchronized with the analog video data voltages to the gate lines G1 to Gn under the control of the timing controller 104 during the display period DIS. The line of the display panel to be written is selected. The scan pulse is generated as a pulse swinging between the gate high voltage VGH and the gate low voltage VGL. The display scan driving circuit 204 continuously supplies the gate low voltage VGL to the gate lines G1 to Gn without generating a scan pulse during the touch sensor driving period TS. Accordingly, the gate lines G1 to Gn sequentially supply the gate pulses to the TFTs of the pixels during the display period to sequentially select the lines on which the data is to be written in the display panel 100, and the gate rows during the touch sensor driving period TS. Maintain the voltage VGL. The gate high voltage VGH may be a voltage of approximately 18V to 20V, and the gate low voltage VGL may be a voltage of approximately 0V to 15V.

The touch sensor driving circuit 302 supplies the common voltage Vcom to the Tx lines T1 to Tj during the display period DIS. The touch sensor driving circuit 302 sequentially outputs the touch sensor driving pulses through its output channels during the touch sensor driving period TS, and sequentially applies the touch sensor driving pulses to the Tx lines T1 to Tj to touch the touch sensors. Scan them, and output the touch sensor driving pulse by repeating the output channel two or more times. Accordingly, the touch sensor driving circuit 302 performs a touch sensor scanning operation of sequentially supplying touch sensor driving pulses to all the Tx lines T1 to Tj from the first Tx line T1 to the j th Tx line Tj. 1 Repeat twice or more within the touch sensor drive period TS. The touch sensor driving circuit 302 may be implemented as a scan drive IC having a circuit configuration substantially the same as that of the scan drive IC of the display scan driving circuit 204.

The touch sensor driving period TS may be allocated to the remaining time after subtracting the display period DIS within one frame period. Considering the one touch sensor driving period that can be allocated within one frame period and the sampling time of the touch sensor output, the touch sensor driving circuit 302 is assigned to each of its output channels within one touch sensor driving period TS. N (N is a positive integer of 2 to 10) can be repeated to output the touch sensor drive pulse.

The touch sensor read circuit 304 supplies the common voltage Vcom to the Rx lines R1 to Ri during the display period DIS, and supplies the Rx lines R1 to Ri during the touch sensor driving period TS. The touch reference voltage Vref is supplied. The touch reference voltage Vcom may be set to a DC voltage higher than 0V and lower than 3V. The touch sensor reading circuit 304 samples and amplifies the analog output (voltage of mutual capacitance) of the touch sensors input through the Rx lines R1 to Ri and converts the digital output data into digital touch data to the touch controller 306. send. Here, the touch sensor reading circuit 304 repeatedly samples the output of each of the touch sensors N times within one touch sensor driving period TS by N scanning operations of the touch sensor driving circuit 302.

The touch controller 306 stores digital touch data repeatedly input N times from the touch sensor reading circuit 304 in the memory 308 within one touch sensor driving section TS. The touch controller 306 reads digital touch data repeatedly output N times from the same touch sensor from the memory 308 and reduces noise components incorporated into the digital touch data based on a result of calculating the digital touch data. The touch controller 306 detects touch data equal to or greater than the reference value by comparing the digital touch data having reduced noise component with a preset reference value REF. The touch controller 306 analyzes touch data over a reference value using a preset touch recognition algorithm and calculates coordinate values of touched touch sensors. The coordinate value data of the touch position output from the touch controller 306 is transmitted as touch digital touch data in HID format to an external host system. The host system executes an application program associated with the coordinate value of the touch position.

The timing controller 104 receives timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal Data Enable, DE, and a main clock MCLK input from an external host system. Display timing control signals for controlling the operation timing of the display data driver circuit 202 and the display scan driver circuit 204 are generated. The timing control signal of the display scan driving circuit 204 includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal (Gate output enable, GOE), and a shift direction control. Signal DIR and the like. The timing control signal of the display data driving circuit 202 includes a source sampling clock (SSC), a polarity control signal (Polarity, POL), a source output enable signal (SOE), and the like.

The timing controller 104 generates touch sensor timing control signals Ctx and Crx for controlling the operation timing of the touch sensor driving circuit 302 and the touch sensor reading circuit 304. The timing control signal of the touch sensor driving circuit 302 includes a start pulse (SGSG in FIG. 11), a shift clock (SGSG in FIG. 11), an output enable signal (SGOE in FIG. 11), and the like. The timing control signal of the touch sensor read circuit 304 may include a reset pulse (RST in FIGS. 9 to 11), first and second sample and hold pulses (S0 and SH1 in FIGS. 9 and 11). And gate-on pulses (tG in FIGS. 9 to 10), data transfer start pulses (FST), ADC clocks (FSR), and the like.

The timing controller 104 time-divisions one frame period into the display period DIS and the touch sensor driving period TS as shown in FIG. 8. The timing controller 104 may allocate a predetermined initialization period DP during which the display operation and the touch sensor operation are temporarily stopped for a predetermined period between the display period DIS and the touch sensor driving period TS. The touch sensor read circuit 304 supplies the touch reference voltage Vref to the Rx lines R1 to Ri under the control of the timing controller 104 during the initialization period DP. The initialization period DP is set to a time required until the voltages of the Rx lines R1 to Ri are stabilized to the touch reference voltage Vref.

The timing controller 104 enables the outputs of the display data driver circuit 202 and the display scan driver circuit 204 to display the video data on the pixels during the display period DIS. The timing controller 104 enables the output of the touch sensor driving circuit 302 and enables the touch signal sampling of the touch sensor reading circuit 304 during the touch sensor driving period TS. The display period and the touch sensor driving period may be appropriately adjusted in consideration of panel characteristics according to the type of display panel 100.

FIG. 6 is an equivalent circuit diagram illustrating a part of a pixel array and touch sensors embedded in the display panel 100. 6, "D1, Dk (k is a positive integer less than m), Dk + 1" are data lines, and "Gx" is a gate line.

7 is a plan view illustrating a part of a pixel array and touch sensors embedded in the display panel 100.

Referring to FIG. 7, the Tx lines T1 to Tj include transparent conductive block patterns T11 to T23 and link patterns L11 to L22. In Fig. 7, "D1 to D3 ..." are data lines, and "G1 to G3 ..." are gate lines.

The size of each of the transparent conductive block patterns T11 to T23 is patterned larger than that of each of the pixels. Each of the transparent conductive block patterns T11 to T23 overlaps the pixels with an insulating layer interposed therebetween, and may be patterned with a transparent conductive material such as indium tin oxide (ITO). The link patterns L11 to L22 electrically connect the neighboring transparent conductive block patterns T11 to T23 in the lateral direction (or the horizontal direction) across the Rx lines R1 and R2. The link patterns L11 to L22 overlap the Rx lines R1 and R2 with an insulating layer interposed therebetween. The link patterns L11 to L22 are patterned with metals such as metal aluminum (Al), aluminum neodium (AlNd), molybdenum (Mo), chromium (Cr), copper (Cu), and silver (Ag), which have high electrical conductivity. It may be patterned with a transparent conductive material.

The first Tx line includes a plurality of transparent conductive block patterns T11 to T13 connected along the transverse direction via the link patterns L11 and L12. The second Tx line includes a plurality of transparent conductive block patterns T21 to T23 connected along the transverse direction via the link patterns L21 and L22.

The Rx lines R1 and R2 are long patterned along the longitudinal direction (or vertical direction) between the transparent conductive block patterns T11 to T23 neighboring in the lateral direction. The Rx lines R1 and R2 may be formed of a transparent conductive material such as ITO. Each of the Rx lines R1 and R2 may overlap with a plurality of pixels not shown.

8 is a waveform diagram illustrating a method of driving a display device according to an exemplary embodiment of the present invention.

Referring to FIG. 8, the display scan driving circuit 204 sequentially supplies gate pulses synchronized with the analog video data voltage to the gate lines G1 to Gn under the control of the timing controller 104 during the display period DIS. do.

The touch sensor driving circuit 302 repeats the touch sensor scanning operation N times to sequentially apply the touch sensor driving pulses to all the Tx lines T1 to Tj during the touch sensor driving period TS. For example, the touch sensor driving period TS may be time-divided into first to Nth touch sensor scanning periods SS1 to SSN. In the touch sensor driving period TS, the touch sensor driving pulses are sequentially applied to all the Tx lines T1 to Tj for each of the touch sensor scanning periods SS1 to SSN.

The touch sensor readout circuit 304 samples the analog output of the touch sensor by sampling the voltages of the Rx lines R1 to Ri after the touch sensor drive pulse as shown in FIGS. 3 and 4 during the touch sensor driving period TS. And amplify and convert the digital touch data. The touch controller 306 reads digital touch data repeatedly output N times from the same touch sensor from the memory 308 and reduces noise components incorporated into the digital touch data based on a result of calculating the digital touch data.

9 is a circuit diagram showing the touch sensor read circuit 304 in detail. 10 is a waveform diagram illustrating a timing control signal of the touch sensor read circuit 304.

9 and 10, the touch sensor readout circuit 304 may include a gate switch Tsw, an operation amplifier (OP), a reset switch (SWR), a capacitor (C1), first and first electrodes. Two sampling switches SW0, SW1, an output buffer 42, an analog to digital converter (hereinafter referred to as " ADC ") 44, and the like.

The reset switch SWR and the capacitor C1 are connected between the non-inverting input terminal and the output terminal of the operational amplifier. The touch reference voltage Vref is supplied to the inverting terminal of the operational amplifier OPamp. The op amp amplifies the voltage on the Rx line. The capacitor C1 stores the voltage difference between the non-inverting input terminal and the output terminal of the operational amplifier to sample the voltage of the Rx line. The reset switch SWR short-circuits the non-inverting input terminal and the output terminal of the operational amplifier in response to the reset pulse RST to discharge and initialize the voltage of the capacitor C1.

The gate switch Tsw is turned on in response to the gate-on pulse tG to supply the voltage of the Rx line to the capacitor C1 connected to the non-inverting input terminal of the operational amplifier. Since the voltage of the mutual capacitance Cm is supplied to the capacitor C1 by the touch sensor driving pulses supplied to the Tx lines T1 to Tj, the gate switch Tsw may be omitted.

The first sampling switch element SWO is turned on in response to the first sample-and-hold pulse SH0 to supply the touch reference voltage Vref of the Rx line to the output buffer 42 so as to supply the touch reference voltage Vref of the Rx line. Sample the. The second sampling switch device SW1 is turned on in response to the second sample and hold pulse SH1 to supply the output buffer 42 with the voltage of the Rx line changed from the touch reference voltage Vref after the touch to the output buffer 42. Sample the voltage change.

The output buffer 42 transmits voltages input through the first and second sampling switches SW0 and SW1 in response to the data transfer start pulse FST to the ADC 44 in response to the data transfer start pulse FST. Supply. The ADC 44 converts the analog output voltage of the touch sensor input from the output buffer 42 into digital touch data and supplies it to the touch controller 306.

FIG. 11 is a timing diagram illustrating display timing control signals generated in the display period DIS and touch sensor timing signals generated in the touch sensor driving period TS.

Referring to FIG. 11, the display data driving circuit 202 and the display scan driving circuit 204 generate an output in a display period in response to display timing control signals GSP, GOE, SOE, GSC, and the like. Write video data in the. The display data driving circuit 202 maintains the previous data voltage or outputs the base voltage GND during the touch sensor driving period TS. The display scan driving circuit 204 maintains the gate low voltage VGL during the touch sensor driving period TS. The pixels maintain the data voltage charged in the display period DIS due to the storage capacitor Cst during the touch sensor driving period TS.

The touch sensor driving circuit 302 and the touch sensor reading circuit 304 are disabled during the display period. The touch sensor driving circuit 302 and the touch sensor reading circuit 304 output in response to touch sensor timing control signals (SGSP, SGOE, RST, SH0, SH1, SGSC, FST, FSR, etc.) during the touch sensor driving period. Enable Start pulse (SGSP) occurs N times. The touch sensor driving circuit 302 starts to output the touch sensor driving pulse to the first Tx line whenever the start pulse SGSP is generated, and shifts the start pulse SGSP every shift clock SGSC to drive the touch sensor. The pulse is repeatedly output N times to the Tx lines T1 to Tj.

12 is a flowchart illustrating a control procedure of a method of driving a display device according to an exemplary embodiment of the present invention step by step.

Referring to FIG. 12, the display device of the present invention scans the touch sensors of the touch screen during the touch sensor driving period TS to read analog outputs of the touch sensors and converts the analog outputs into digital touch data. S3) The display device of the present invention stores the digital touch data in the memory 308. (S4) 1 Steps S1 to S4 until the output of each of the touch sensors is read N times within the touch sensor driving period TS. Is repeated (S5).

The display device of the present invention adds, subtracts or averages digital touch data obtained from the same touch sensor within one touch sensor driving period TS, and removes noise components included in the output of the touch sensor using the result. (S6) The touch sensor-embedded display device of the present invention writes data in the pixels during the display period DIS.

13 is a waveform diagram illustrating a noise removing method according to a first embodiment of the present invention. This noise removing method is executed by the touch controller 306.

Referring to FIG. 13, the touch controller 306 adds N digital touch data obtained from the same touch sensor. This method is performed on digital touch data obtained from all touch sensors.

The driving voltage of the display panel or the driving voltage of the driving circuit IC, for example, as described above, is affected by the variation of the common voltage Vcom, the touch reference voltage Vref, and the ground voltage GND. Time-dependent noise components can be added to the outputs of the same touch sensor obtained in the < RTI ID = 0.0 > Therefore, the digital touch data obtained within one touch sensor driving period TS from the same touch sensor should be the same value, but may be different from each other by the noise component.

Adding digital touch data obtained from the same touch sensor also adds noise components but results in a larger effective touch value with a relatively large value. Therefore, when the digital touch data obtained from the same touch sensor is added, the difference between the effective touch value and the noise component is increased, thereby obtaining an effect of removing the noise component.

14 is a waveform diagram illustrating a noise removing method according to a second embodiment of the present invention. This noise removing method is executed by the touch controller 306.

Referring to FIG. 14, the touch controller 306 subtracts N digital touch data obtained from the same touch sensor. This method is performed on digital touch data obtained from all touch sensors.

Time-dependent noise components may be added to outputs of the same touch sensor obtained within one touch sensor driving period TS under the influence of the driving voltage of the display panel or the driving voltage of the driving circuit IC. Therefore, the digital touch data obtained within one touch sensor driving period TS from the same touch sensor should be the same value, but may be different from each other by the noise component.

Subtracting digital touch data obtained from the same touch sensor also reduces the effective touch value, but almost eliminates noise components having a small value. Therefore, by subtracting the digital touch data obtained from the same touch sensor, the difference between the effective touch value and the noise component is greater, thereby obtaining the effect of removing the noise component.

The noise removing method according to the third exemplary embodiment of the present invention calculates an average value of digital touch data obtained within one touch sensor driving period TS from the same touch sensor. For example, if the digital data obtained three times consecutively from the Nth touch sensor in one touch sensor driving period TS is "1st RO data (n), 2nd RO data (n), 3rd RO data (n)". The average may be obtained as {1st RO data (n) + 2nd RO data (n) + 3rd RO data (n)} / 3. The calculated average value may be selected as the final output of the n th touch sensor. In the average calculation method, since the effective touch value is larger than the noise component, a noise removing effect can be obtained.

The noise removing method according to the fourth exemplary embodiment of the present invention calculates an average value of digital touch data obtained within one touch sensor driving period TS from the same touch sensor. For example, if the digital data obtained three times consecutively from the Nth touch sensor in one touch sensor driving period TS is "1st RO data (n), 2nd RO data (n), 3rd RO data (n)". The average may be obtained as {1st RO data (n) + 2nd RO data (n) + 3rd RO data (n)} / 3.

The noise removing method according to the fourth exemplary embodiment of the present invention compares the average value with a predetermined threshold to exclude digital touch data having the largest difference from the average value, and selects a larger value among the remaining values as the final output of the n-th touch sensor. do. For example, in "{1st RO data (n) + 2nd RO data (n) + 3rd RO data (n)} / 3", "2nd RO data (n)" is the noise component (Δ) and 2nd RO is added. 2nd RO data (n) + Δ is excluded if data (n) + Δ and its value is the largest difference from the average value. Excluding the excluded data, "1st RO data (n)" and "" 3rd RO data (n)} / 3 "remain, the larger of which is selected as the final output of the nth touch sensor. Since the data added with the noise component is removed and the data having the largest effective touch value is selected, the noise removing effect can be obtained.

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.

100: display panel 104: timing controller
202: display data driver circuit 204: display scan driver circuit
302: touch sensor driving circuit 304: touch sensor reading circuit
306: touch controller 308: memory

Claims (13)

Touch sensors;
A touch sensor driving circuit which outputs the touch sensor driving pulses two or more times through each of the output channels during the touch sensor driving period and repeatedly supplies the touch sensor driving pulses to each of the Tx lines connected to the touch sensors at least twice;
A touch sensor reading circuit for repeatedly sampling and amplifying the output of each of the touch sensors two or more times through Rx lines connected to the touch sensors during the touch sensor driving period and converting the amplified data into digital touch data; And
During operation of the touch sensor, the digital touch data obtained from each of the touch sensors at least two times is stored in a memory and the digital touch data repeatedly output from each of the touch sensors is added, subtracted, and averaged. Including a touch controller to
And the touch controller calculates a plurality of digital touch data obtained from the same touch sensor.
The method of claim 1,
The touch sensors are formed on a display panel,
The display panel further includes data lines for supplying a data voltage to pixels and gate lines for supplying scan pulses to the pixels.
And the Tx lines and the Rx lines intersect with each other and mutual capacitances are formed at an intersection thereof.
The method of claim 2,
A display data driver circuit for supplying an analog video dayton voltage to the data lines during a display period;
A display scan driving circuit for sequentially supplying scan pulses synchronized with the analog video data voltage to the gate lines during the display period; And
Time-dividing one frame period into the display period and the touch sensor driving period to control operation timings of the display data driving circuit and the display scan driving circuit during the display period, and the touch sensor driving circuit during the touch sensor driving period. And a timing controller for controlling an operation timing of the touch sensor reading circuit.
The method of claim 1,
The touch controller,
And a plurality of digital touch data obtained from the same touch sensor to remove noise of an output signal obtained from the touch sensor.
The method of claim 1,
The touch controller,
And a noise of an output signal obtained from the touch sensor by subtracting a plurality of digital touch data obtained from the same touch sensor.
The method of claim 1,
The touch controller,
And averaging a plurality of digital touch data obtained from the same touch sensor to remove noise of an output signal obtained from the touch sensor.
The method of claim 1,
The touch controller,
Averaging a plurality of digital touch data obtained from the same touch sensor,
Touch sensor, characterized in that to remove the noise of the output signal obtained from the touch sensor by excluding the digital touch data having the largest difference from the average operation result and selecting the digital touch data of the largest value among the remaining digital touch data Display device.
Repeatedly supplying a touch sensor driving pulse to each of the Tx lines connected to the touch sensors during the touch sensor driving period two or more times;
Repeatedly sampling and amplifying the output of each of the touch sensors two or more times via Rx lines connected to the touch sensors during the touch sensor driving period and converting the digital touch data into digital touch data; And
During operation of the touch sensor, the digital touch data obtained from each of the touch sensors at least two times is stored in a memory and the digital touch data repeatedly output from each of the touch sensors is added, subtracted, and averaged. Including the steps of:
The operation of driving the display device having a touch sensor, characterized in that for calculating a plurality of digital touch data obtained from the same touch sensor.
The method of claim 8,
Time-dividing one frame period into a display period and the touch sensor driving period to write video data to the pixels of the display panel during the display period, and to drive the touch sensors during the touch sensor driving period. Method of driving a display device having a.
The method of claim 8,
The step of performing the operation,
And removing noise of an output signal obtained from the touch sensor by adding a plurality of digital touch data obtained from the same touch sensor.
The method of claim 8,
The step of performing the operation,
And subtracting a plurality of digital touch data obtained from the same touch sensor to remove noise of an output signal obtained from the touch sensor.
The method of claim 8,
The step of performing the operation,
And averaging a plurality of digital touch data obtained from the same touch sensor to remove noise of an output signal obtained from the touch sensor.
The method of claim 8,
The step of performing the operation,
Averaging a plurality of digital touch data obtained from the same touch sensor; And
And removing the noise of the output signal obtained from the touch sensor by excluding the digital touch data having the largest difference from the average calculation result and selecting the digital touch data having the largest value among the remaining digital touch data. A method of driving a display device having a touch sensor.

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