KR101778731B1 - 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 outputs a touch sensor driving pulse through each of output channels more than twice during a touch sensor driving period, The touch sensor driving circuit repeatedly supplies the touch sensor driving pulses to the touch sensors through the Rx lines connected to the touch sensors during the touch sensor driving period. A touch sensor docking circuit for outputting digital data at least two times from each of the touch sensors during the touch sensor driving period by converting the data into digital touch data using an analog-to-digital converter (ADC) Storing the digital touch data obtained at least two times from each of the touch sensors in a memory And performing an addition, subtraction and averaging operation on the digital touch data obtained from the same touch sensor to increase the difference between the effective touch value and the noise value in the digital touch data obtained from the touch sensors, And a touch controller that reduces components.

Description

TECHNICAL FIELD [0001] The present invention relates to a display device having a touch sensor,

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

User input means has been replaced by a touch sensor in a button-type switch in accordance with the trend of lightening and slimming of household appliances and portable information devices. A touch screen applied to a display device includes a plurality of touch sensors. The touch sensors can be embedded in the display panel in an in-cell type. Hereinafter, the display device in which the touch sensors are incorporated in the display panel will be referred to as a touch sensor built-in display device.

Capacitive touch sensors may be implemented in a mutual capacitance manner. The capacitive touch sensors include mutual capacitance Cm formed at intersections of signal wires Tx and Rx intersecting with each other as shown in FIG. 1A. When the finger approaches the mutual capacitance Cm of the touch sensor as shown in FIG. 1B, the electric field between the electrodes is cut off and the amount of the mutual capacitance Cm is reduced. Therefore, the capacitive touch sensors can recognize the touch by measuring the change in the charge amount of the mutual capacitance Cm before and after the touch.

As shown in FIGS. 2A and 2B, when the output RO of the touch sensor is compared with a predetermined reference value REF and is equal to or greater than the reference value REF, the output RO of the touch sensor is recognized as the output of the touched touch sensor. In the touch sensor built-in type display device, the output RO of the touch sensor can be influenced by the driving voltage of the display panel, the touch reference voltage, etc. through the parasitic capacitance in the display panel. For example, the ideal output RO of the touch sensor is the same as that of FIG. 2A, but the output RO of the touch sensor is affected by the signal voltage supplied through the wirings connected to the pixels, Output.

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

4 shows an example in which the output of the touch sensor fluctuates when the base low voltage (GND) of the drive circuits of the display panel fluctuates. In FIG. 4, reference numerals '23' and '24' denote outputs of untouched touch sensors. The third touch sensor output 23 can be recognized as the output of the touch sensor which is not actually touched when the base low voltage GND does not fluctuate, The voltage of the touch sensor is increased and it can be mistaken for the output of the touch sensor.

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

A display device of the present invention includes a touch sensor that outputs a touch sensor drive pulse through each of output channels during a touch sensor drive period and repeatedly supplies a touch sensor drive pulse to the Tx lines connected to the touch sensors two or more times, The driving circuit repeatedly samples and amplifies the output of each of the touch sensors via the Rx lines connected to the touch sensors during the touch sensor driving period and amplifies the digital touch data by using an analog-to-digital converter (ADC) A touch sensor readout circuit for outputting digital data at least two times from each of the touch sensors during the touch sensor driving period; and a touch sensor readout circuit for sensing the digital touch data obtained from each of the touch sensors, And stores the digital touch data obtained from the same touch sensor Subtracting and averaging operations on the digital touch data obtained from the touch sensors to increase the difference between the effective touch value and the noise value to reduce the noise component. The digital touch data obtained from the same touch sensor includes data read from the memory.

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The touch sensors are formed on a display panel. The display panel further includes data lines supplying data voltages to the pixels and gate lines supplying scan pulses to the pixels. The Tx lines and the Rx lines cross each other and mutual capacities are formed at the intersections.

The display device includes: a display data driving circuit for supplying an analog video data voltage to the data lines during a display period; A display scan driving circuit for sequentially supplying a scan pulse synchronized with the analog video data voltage to the gate lines during the display period; And one frame period is divided into the display period and the touch sensor driving period to control the operation timing of the display data driving circuit and the display scan driving circuit during the display period, And a timing controller for controlling the operation timing of the touch sensor readout 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 subtracts 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 touch controller averages 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 touch controller averages a plurality of digital touch data obtained from the same touch sensor. The touch controller removes digital touch data having the greatest difference from the averaging operation result and selects the largest value of digital touch data among the remaining digital touch data to remove the noise of the output signal obtained from the touch sensor.

The method of driving the display device includes repeatedly supplying a touch sensor drive pulse to each of the Tx lines connected to the touch sensors during the touch sensor driving period at least two times. The Rx lines connected to the touch sensors during the touch sensor driving period The output of each of the touch sensors is repeatedly sampled and amplified at least two times, and converted into digital touch data using an analog-to-digital converter (ADC) And storing the digital touch data obtained at least twice from each of the touch sensors during the touch sensor driving period in a memory and adding, subtracting, and averaging the digital touch data obtained from the same touch sensor And the touch sensors < RTI ID = 0.0 > And increasing the difference between the valid touch value and the noise value to reduce the noise component. The digital touch data obtained from the same touch sensor includes data read from the memory.

In the present invention, the output of the touch sensors is repeatedly sampled within one touch sensor driving period, and the noise components are removed by adding, subtracting, or averaging the data obtained from the same touch sensor. As a result, the present invention can increase the sensitivity of the touch sensors, the recognition rate of the touch, and the reliability of the output data of the touch sensor.

FIGS. 1A and 1B are diagrams showing the operation before and after the touch of the capacitive touch sensors.
2A and 2B are waveform diagrams showing an output of the touch sensor and a reference value.
3 and 4 are waveform diagrams showing an example of a false sense of touch sensors.
5 is a block diagram showing a display device according to an embodiment of the present invention.
6 is an equivalent circuit diagram showing a part of the pixel array and the touch sensors built in the display panel shown in Fig.
7 is a plan view showing a part of the pixel array and the touch sensors built in the display panel shown in Fig.
8 is a waveform diagram showing a driving method of the display device shown in FIG.
FIG. 9 is a circuit diagram showing the touch sensor detour circuit shown in FIG. 5 in detail.
10 is a waveform diagram showing a timing control signal of the touch sensor readout path shown in FIG.
11 is a timing diagram showing display timing control signals generated during a display period and touch sensor timing signals generated during a touch sensor driving period.
FIG. 12 is a flowchart showing the control procedure of the driving method of the display device shown in FIG. 5 step by step.
13 is a waveform diagram showing a noise removing method according to the first embodiment of the present invention.
14 is a waveform diagram illustrating a noise removing method according to the 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, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The display device of the present invention can be applied to a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an organic light emitting display , OLED, electrophoresis (EPD), and the like, and touch sensors embedded in the display panel of the flat panel display device as an insulator type. Note that in the following embodiments, a liquid crystal display element is described as an example of a flat display element, but the display device of the present invention is not limited to a liquid crystal display element.

5, a display device according to an exemplary embodiment of the present invention includes a display panel 100, a display data driving circuit 202, a display scan driving circuit 204, a touch sensor driving circuit 302, 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. A plurality of gate lines G1 to Gn, n, which intersect the data lines D1 to Dm and a plurality of data lines D1 to Dm, m are positive integers, are connected to the lower substrate of the display panel 100, A plurality of TFTs (TFT of FIG. 6) formed at the intersections of the data lines D1 to Dm and the gate lines G1 to Gn, liquid crystal cells (Clc A storage capacitor (Cst in FIG. 6), a touch sensor, etc., connected to the pixel electrode 11 to maintain the voltage of the liquid crystal cell, and the like do.

The touch sensors cross the Tx lines (T1 to Tj, j is a positive integer smaller than n) and the Tx lines (T1 to Tj) side by side with the gate lines G1 to Gn as shown in Figs. 6 and 7 The data lines D1 to Dm are connected to the intersections of the Rx lines (R1 to Ri, i is a positive integer smaller than m) and the Tx lines (T1 to Tj) and the Rx lines (R1 to Ri) A mutual capacitance Cm formed, and the like.

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

The pixels of the display panel 100 are formed in a pixel region defined by the data lines D1 to Dm and the gate lines G1 to Gn and arranged in a matrix form. The liquid crystal cells of each of the pixels are driven by an electric field applied in accordance with the difference between the data voltage applied to the pixel electrode 11 and the common voltage Vcom applied to the common electrode 12 to control the amount of incident light . The TFTs are turned on in response to the gate pulse 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. On the other hand, the lower glass substrate of the display panel 100 may be implemented as a COT (Color Filter On TFT) 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 TN (Twisted Nematic) mode and VA (Vertical Alignment) mode. And is formed on the lower substrate together with the pixel electrode 11 in the horizontal electric field driving system. 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 connected to the common electrode 12 via the Tx lines T1 to Tj and the Rx lines R1 to Ri The voltage Vcom can be supplied.

On the upper substrate and the lower substrate of the display panel 100, a polarizing plate is attached and an alignment film for forming a pre-tilt angle of the liquid crystal is formed on the inner surface in contact with the liquid crystal. A column spacer for maintaining a cell gap of the liquid crystal cell may be formed between the upper substrate and the lower substrate of the display panel 100.

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

The display scan drive circuit 204 includes one or more scan drive ICs. The scan driver IC sequentially supplies a scan pulse (or gate pulse) 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, And selects the line of the display panel to be written. The scan pulse is generated as a pulse swinging between the gate high voltage (VGH) and the gate low voltage (VGL). The display scan driver circuit 204 continuously supplies the gate line voltage VGL to the gate lines G1 to Gn without generating the scan pulse during the touch sensor drive period TS. Accordingly, the gate lines G1 to Gn sequentially supply the gate pulse to the TFTs of the pixels during the display period to sequentially select the line to which the data is to be written in the display panel 100, And maintains the voltage VGL. The gate high voltage VGH may be a voltage between approximately 18V and 20V, and the gate low voltage VGL may be a voltage between approximately 0V and -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 touch sensor driving pulses through its output channels during the touch sensor driving period TS to sequentially apply touch sensor driving pulses to the Tx lines T1 to Tj, And outputs a touch sensor drive pulse by repeating the operation twice or more on each of the output channels. Accordingly, the touch sensor driving circuit 302 performs a touch sensor scanning operation for sequentially supplying touch sensor driving pulses to all the Tx lines Tl through Tj from the first Tx line T1 to the jth Tx line Tj 1 It is repeated twice or more within the touch sensor driving period (TS). The touch sensor driver circuit 302 may be implemented as a scan driver IC having substantially the same circuit configuration as the scan driver IC of the display scan driver circuit 204.

The touch sensor driving period TS may be allocated within a frame period with the remaining time minus the display period DIS. Considering one touch sensor driving period and the sampling time of the touch sensor output that can be allocated within one frame period, the touch sensor driving circuit 302 outputs a signal to each of its output channels within one touch sensor driving period TS N (N is a positive integer equal to or greater than 2 and equal to or less than 10) times to output a touch sensor drive pulse.

The touch sensor readout circuit 304 supplies the common voltage Vcom to the Rx lines R1 to Ri during the display period DIS and outputs the common voltage Vcom to the Rx lines R1 to Ri during the touch sensor driving period TS And supplies the touch reference voltage Vref. The touch reference voltage Vcom can be set to a direct current voltage higher than 0 V and 3 V or lower. The touch sensor readout circuit 304 samples and amplifies the analog output (voltage of mutual capacitance) of the touch sensors input through the Rx lines R1 to Ri, converts the analog output into digital touch data, and outputs the digital touch data to the touch controller 306 send. Here, the touch sensor readout circuit 304 repeatedly samples the output of each of the touch sensors N times in one touch sensor driving period TS by the N times scanning operation of the touch sensor driving circuit 302.

The touch controller 306 stores the digital touch data repeatedly inputted N times from the touch sensor docking circuit 304 in the touch sensor driving section TS in the memory 308. [ The touch controller 306 reads the digital touch data repeatedly output N times from the same touch sensor from the memory 308 and reduces the noise components mixed in the digital touch data based on the calculation result of the digital touch data. The touch controller 306 compares the digital touch data with reduced noise components with a predetermined reference value REF to detect touch data equal to or greater than a reference value. The touch controller 306 analyzes the touch data of a reference value or more by a preset touch recognition algorithm and calculates coordinate values of the touch sensors. The coordinate value data of the touch position output from the touch controller 306 is transmitted to an external host system as touch digital touch data in the HID format. The host system executes the application program associated with the coordinate value of the touch location.

The timing controller 104 receives a timing signal such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE and a main clock MCLK from an external host system And generates display timing control signals for controlling the operation timings of the display data driving circuit 202 and the display scan driving circuit 204. [ 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 GOE, 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 POL and a source output enable signal SOE.

The timing controller 104 generates touch sensor timing control signals Ctx and Crx for controlling the operation timings 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 (SGSP in FIG. 11), a shift clock (SGSC in FIG. 11), an output enable signal (SGOE in FIG. 9 to 11), the first and second sample and hold pulses (SH0 and SH1 in Figs. 9 to 11), and the second and third sample and hold pulses A gate-on pulse (tG in Figs. 9 to 10), a data transfer start pulse (FST), an ADC clock (FSR), and the like.

The timing controller 104 divides one frame period into a display period (DIS) and a touch sensor driving period (TS) as shown in FIG. The timing controller 104 may allocate a predetermined initialization period DP in 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 readout 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 voltage of the Rx lines R1 to Ri is stabilized to the touch reference voltage Vref.

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

6 is an equivalent circuit diagram showing a part of the pixel array and the touch sensors built in the display panel 100. As shown in Fig. In Fig. 6, "D1, Dk (k is a positive integer smaller than m), Dk + 1" are data lines, and "Gx" is a gate line.

7 is a plan view showing a part of the pixel array and the touch sensors built in the display panel 100. FIG.

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 ..." represent gate lines.

The size of each of the transparent conductive block patterns T11 to T23 is larger than the size of each of the pixels. Each of the transparent conductive block patterns T11 to T23 overlaps the pixels with the insulating layer therebetween, and can be patterned with a transparent conductive material such as ITO (Indium Tin Oxide). The link patterns L11 to L22 electrically connect neighboring transparent conductive block patterns T11 to T23 in the lateral direction (or horizontal direction) across the Rx lines R1 and R2. The link patterns L11 to L22 overlap the Rx lines R1 and R2 with the insulating layer sandwiched therebetween. The link patterns L11 to L22 may be patterned with metal such as metallic aluminum (Al), aluminum neodymium (AlNd), molybdenum (Mo), chrome (Cr), copper (Cu) , And may be patterned with a transparent conductive material.

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

The Rx lines R1 and R2 are patterned along the longitudinal direction (or vertical direction) between the transversely adjacent transparent conductive block patterns T11 to T23. 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 embodiment of the present invention.

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 for sequentially applying the touch sensor driving pulse to all the Tx lines T1 to Tj N times 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. The touch sensor driving period TS sequentially applies touch sensor driving pulses to all the Tx lines Tl through Tj for each of the touch sensor scanning periods SS1 through SSN.

The touch sensor readout circuit 304 samples the voltage of the Rx lines R1 to Ri after the touch sensor drive pulse as shown in FIGS. 3 and 4 during the touch sensor drive period TS to sample the analog output of the touch sensor Amplifies and converts the data into digital touch data. The touch controller 306 reads the digital touch data repeatedly output N times from the same touch sensor from the memory 308 and reduces the noise components mixed in the digital touch data based on the calculation result of the digital touch data.

9 is a circuit diagram showing the touch sensor readout circuit 304 in detail. 10 is a waveform diagram showing a timing control signal of the touch sensor readout circuit 304. In FIG.

9 and 10, the touch sensor readout circuit 304 includes a gate switch Tsw, an operation amplifier (OP amp), a reset switch SWR, a capacitor C1, 2 sampling switches SW0 and SW1, an output buffer 42, an analogue to digital converter (ADC) 44, and the like.

A reset switch (SWR) and a capacitor (C1) are connected between the non-inverting input terminal and the output terminal of the operational amplifier. A touch reference voltage Vref is supplied to the inverting terminal of the operational amplifier OPamp. The operational amplifier 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 initialize by discharging 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. The gate switch Tsw may be omitted because the voltage of the mutual capacitance Cm is supplied to the capacitor C1 by the touch sensor drive pulse supplied to the Tx lines T1 to Tj.

The first sampling switch element SWO is turned on in response to the first sample and hold pulse SH0 and supplies the touch reference voltage Vref of the Rx line to the output buffer 42 by supplying the touch reference voltage Vref of the Rx line to the output buffer 42, Lt; / RTI > The second sampling switch element 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, The voltage variation amount is sampled.

The output buffer 42 outputs voltages input through the first and second sampling switches SW0 and SW1 to the ADC 44 in response to the data transfer start pulse FST 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 the digital touch data to the touch controller 306.

11 is a timing chart showing display timing control signals generated in the display period DIS and touch sensor timing signals generated in the touch sensor driving period TS.

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, etc.) As shown in Fig. The display data driving circuit 202 maintains the previous data voltage or outputs the ground 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 docking circuit 304 are disabled during the display period. The touch sensor driver circuit 302 and the touch sensor readout circuit 304 respond to the touch sensor timing control signals SGSP, SGOE, RST, SH0, SH1, SGSC, FST, FSR, Lt; / RTI > The start pulse SGSP occurs N times. Each time the start pulse SGSP is generated, the touch sensor driving circuit 302 starts to output the touch sensor driving pulse to the first Tx line and shifts the start pulse SGSP every time the shift clock SGSC, The pulse is repeatedly output to the Tx lines (T1 to Tj) N times.

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

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), reads the analog outputs of the touch sensors, and converts the analog output into digital touch data. S3) The display device of the present invention stores the digital touch data in the memory 308. (S4) Until the output of each of the touch sensors is read out N times within one touch sensor driving period TS, (S5)

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

13 is a waveform diagram showing a noise removing method according to the 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 for digital touch data obtained from all the touch sensors.

The driving voltage of the display panel and the driving voltage of the driving circuit IC are affected by the variations of the common voltage Vcom, the touch reference voltage Vref and the ground voltage GND as described above, A noise component that varies with time may be added to the outputs of the same touch sensor obtained in the same manner. Accordingly, the digital touch data obtained within one touch sensor driving period (TS) from the same touch sensor should have the same value, but may differ from each other depending on the noise component.

When the digital touch data obtained from the same touch sensor is added, the noise components are also added, but the effective touch value having a relatively large value becomes larger. 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 becomes larger, so that the noise component is removed.

14 is a waveform diagram illustrating a noise removing method according to the 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 for digital touch data obtained from all the touch sensors.

A noise component that varies with time may be added to the outputs of the same touch sensor obtained within one touch sensor driving period TS due to the influence of the driving voltage of the display panel and the driving voltage of the driving circuit IC. Accordingly, the digital touch data obtained within one touch sensor driving period (TS) from the same touch sensor should have the same value, but may differ from each other depending on the noise component.

When the digital touch data obtained from the same touch sensor is subtracted, the effective touch value is also reduced, but noise components having a small value are almost eliminated. Therefore, when the digital touch data obtained from the same touch sensor is subtracted, the difference between the effective touch value and the noise component becomes larger, and thus the noise component is removed.

The noise removing method according to the third embodiment of the present invention calculates the average value of the digital touch data obtained in one touch sensor driving period (TS) from the same touch sensor. For example, if the digital data obtained three times in succession from the Nth touch sensor within one touch sensor driving period TS are "1st RO data (n), 2nd RO data (n), 3rd RO data The average can 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, the noise reduction effect can be obtained.

The noise removing method according to the fourth 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 in succession from the Nth touch sensor within one touch sensor driving period TS are "1st RO data (n), 2nd RO data (n), 3rd RO data The average can be obtained as {1st RO data (n) + 2nd RO data (n) + 3rd RO data (n)} / 3.

In the noise reduction method according to the fourth embodiment of the present invention, the average value is compared with a predetermined threshold to eliminate the digital touch data having the greatest difference from the average value, and a large value among the remaining values is selected as the final output of the n-th touch sensor do. For example, in the case of "1st RO data (n) + 2nd RO data (n) + 3rd RO data (n)} / 3" If data (n) + Δ and the difference from the mean value is greatest, 2nd RO data (n) + Δ is excluded. (N) is selected as the final output of the n-th touch sensor, the larger value is selected as the final output of the n-th touch sensor. The noise added data can be removed and the data with the largest effective touch value can be selected.

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 driving circuit 204: Display scan driving circuit
302: touch sensor driving circuit 304: touch sensor docking circuit
306: Touch controller 308: Memory

Claims (15)

A touch sensor driving circuit that outputs a touch sensor driving pulse through each of the output channels during the touch sensor driving period twice or more to repeatedly supply a touch sensor driving pulse to the Tx lines connected to the touch sensors at least twice;
The output of each of the touch sensors is repeatedly sampled and amplified twice or more through the Rx lines connected to the touch sensors during the touch sensor driving period and converted into digital touch data using an analog-to-digital converter (ADC) A touch sensor docking circuit for outputting digital data from each of the touch sensors at least two times during a touch sensor driving period; And
The digital touch data obtained from each of the touch sensors at least twice during the touch sensor driving period is stored in a memory and any one of addition, subtraction and averaging is performed on the digital touch data obtained from the same touch sensor And a touch controller for reducing a noise component by increasing a difference between a valid touch value and a noise value in digital touch data obtained from the touch sensors,
Wherein the digital touch data obtained from the same touch sensor includes data read from the memory.
The method according to claim 1,
The touch sensors are formed on a display panel,
Wherein the display panel further comprises data lines for supplying a data voltage to the pixels and gate lines for supplying a scan pulse to the pixels,
Wherein the Tx lines and the Rx lines cross each other and mutual capacities are formed at the intersections.
3. The method of claim 2,
A display data driving circuit for supplying an analog video data voltage to the data lines during a display period;
A display scan driving circuit for sequentially supplying a scan pulse synchronized with the analog video data voltage to the gate lines during the display period; And
Wherein the control circuit controls the operation timing of the display data driving circuit and the display scan driving circuit during the display period by time-sharing the one frame period between the display period and the touch sensor driving period, Further comprising a timing controller for controlling an operation timing of the touch sensor readout circuit.
The method according to claim 1,
The touch controller includes:
And adding a plurality of digital touch data obtained from the same touch sensor.
The method according to claim 1,
The touch controller includes:
And subtracts a plurality of digital touch data obtained from the same touch sensor.
The method according to claim 1,
The touch controller includes:
And averaging operation of a plurality of digital touch data obtained from the same touch sensor.
The method according to claim 1,
The touch controller includes:
A plurality of digital touch data obtained from the same touch sensor are averaged, digital touch data having the greatest difference from the average calculation result is excluded, and the digital touch data having the largest value among the remaining digital touch data is selected, And the noise of the obtained output signal is removed.
Repeatedly supplying a touch sensor drive pulse to each of the Tx lines connected to the touch sensors during the touch sensor driving period twice or more;
The output of each of the touch sensors is repeatedly sampled and amplified twice or more through the Rx lines connected to the touch sensors during the touch sensor driving period and converted into digital touch data using an analog-to-digital converter (ADC) Generating digital data from each of the touch sensors two or more times during a touch sensor driving period; And
The digital touch data obtained from each of the touch sensors at least twice during the touch sensor driving period is stored in a memory and any one of addition, subtraction and averaging is performed on the digital touch data obtained from the same touch sensor And reducing a noise component by increasing a difference between a valid touch value and a noise value in digital touch data obtained from the touch sensors,
Wherein the digital touch data obtained from the same touch sensor includes data read from the memory.
[Claim 9 is abandoned upon payment of registration fee.] 9. The method of claim 8,
One frame period is divided into a display period and a touch sensor driving period to write video data to pixels of the display panel during the display period and to drive the touch sensors during the touch sensor driving period. The driving method of the display device.
[Claim 10 is abandoned upon payment of the registration fee.] 9. The method of claim 8,
Wherein performing the operation further comprises:
And adding a plurality of digital touch data obtained from the same touch sensor to remove noise of an output signal obtained from the touch sensor.
[Claim 11 is abandoned upon payment of the registration fee.] 9. The method of claim 8,
Wherein performing the operation further comprises:
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.
[12] has been abandoned due to the registration fee. 9. The method of claim 8,
Wherein performing the operation further comprises:
Wherein a noise of an output signal obtained from the touch sensor is removed by averaging a plurality of digital touch data obtained from the same touch sensor.
[13] has been abandoned due to the registration fee. 9. The method of claim 8,
Wherein performing the operation further comprises:
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, The method comprising the steps of: [14] has been abandoned due to the registration fee. The method of claim 3,
A predetermined initialization period is allocated between the display period and the touch sensor driving period,
Wherein the initialization period is set to a time at which the voltage of the Rx lines is stabilized to a preset touch reference voltage.
[Claim 15 is abandoned upon payment of registration fee] The method according to claim 1,
Wherein the touch controller compares the digital touch data with reduced noise components with a preset reference value to detect touch data of the reference value or more and calculate coordinates.

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