KR20130058512A - Apparatus and method for driving touch screen - Google Patents

Abstract

PURPOSE: A touch screen driving device and a method thereof are provided to reduce effect of noise inflowing from a display panel. CONSTITUTION: A Tx driving circuit(32) sequentially supplies a driving pulse to Tx lines and supplies driving pulses having reverse phase with each other to the neighboring Tx lines. An Rx driving circuit(34) samples voltage of a sensor node received through Rx lines coupled to the Tx lines and converts the sampled voltage into digital data. A touch controller(30) controls the Tx driving circuit and the Rx driving circuit, analyzes data due to the final touch with a predetermined touch recognition algorithm and estimates a coordinate of the touch input location.

Description

Touch screen driving device and method {APPARATUS AND METHOD FOR DRIVING TOUCH SCREEN}

The present invention relates to a touch screen driving device and method.

The user interface (UI) allows a user to easily and conveniently control various electric / electronic devices as desired. Representative examples of such a user interface include a keypad, a keyboard, a mouse, an on screen display (OSD), a remote controller having infrared communication or radio frequency (RF) communication function, and the like. User interface technology has been developed to enhance the user's sensibility and ease of operation. Recently, the user interface has evolved into a touch UI, a voice recognition UI, a 3D UI, and the like.

Touch UI is becoming a necessity for portable information devices and is being applied to household appliances. As an example of a touch screen for implementing a touch UI, a mutual capacitance touch screen may sense proximity as well as touch and recognize each touch position of a multi-touch (or proximity).

The mutual capacitive touch screen includes Tx lines, Rx lines intersecting the Tx lines, and sensor nodes formed at the intersection of the Tx lines and the Rx lines. Each of the sensor nodes has a mutual capacity. The touch screen driving device senses a change in the voltage charged in the sensor nodes before and after the touch (or proximity) to judge whether or not the conductive material is in contact (or proximity) and its position.

The touch screen may be adhered to or embedded in the display panel of the display device. The touch screen is susceptible to driving signals of the display panel due to electrical coupling with the display panel. Noise affecting the touch screen due to the driving signal of the display panel causes problems such as touch misrecognition and deterioration of touch sensitivity.

The present invention provides a touch screen driving apparatus and method that can reduce the influence on the noise flowing from the display panel.

The touch screen driving apparatus of the present invention includes a touch screen including Tx lines, Rx lines crossing the Tx lines, and sensor nodes formed at an intersection of the Tx lines and the Rx lines; A Tx driving circuit which sequentially supplies driving pulses to the Tx lines, and supplies driving pulses that are out of phase with each other to neighboring Tx lines; An Rx driving circuit sampling a voltage of a sensor node received through the Rx lines coupled with the Tx lines and converting the sampled voltage into digital data; Immediately after initialization of the touch screen, reference data including the digital data and preset dummy data obtained as a result of the scanning of the touch screen are stored in a memory, and the normal data generated after the touch input on the touch screen is stored in the memory. A data compensator for generating first compensation data by subtracting reference data, integrating the first compensation data, adding a compensation value, and generating final touch data; And a touch controller that controls the Tx driving circuit and the Rx driving circuit, and estimates coordinates of the touch input position by analyzing the final touch furnace data with a preset touch recognition algorithm.

The Tx driving circuit supplies a first driving pulse to the first Tx line and also supplies a second driving pulse that is in phase with respect to the first driving pulse to the second Tx line.

The integral operation of the data compensation unit calculates a difference between vertically neighboring first and second primary compensation data from the first compensation data arranged vertically along the y axis of the touch screen as a first integration result, The difference between neighboring primary compensation data is accumulated by subtracting the first integration result from the third primary compensation data to calculate a second integration result.

Each of the dummy data is set to '0'.

When the compensation value is added to the first compensation data, the minimum value of the first compensation data is changed to '0'.

The touch screen driving method of the present invention comprises sequentially supplying driving pulses to the Tx lines, and supplying driving pulses that are out of phase with each other to neighboring Tx lines; Sampling a voltage at a sensor node received over the Rx lines coupled with the Tx lines and converting the sampled voltage into digital data; Storing reference data in the memory immediately after initialization of the touch screen, the reference data including the digital data and preset dummy data obtained as a result of the scanning of the touch screen; Generating first compensation data by subtracting the reference data from normal data generated after a touch input on the touch screen; Integrating the first compensation data and adding a compensation value to generate final touch data; And estimating coordinates of the touch position by analyzing the final touch furnace data with a preset touch recognition algorithm.

The present invention can reduce the influence of noise introduced from the display panel on the touch screen by simultaneously applying antiphase driving pulses to neighboring Tx lines. Furthermore, the present invention can solve the problem of missing data that may occur when sensing the sensor nodes by applying the antiphase driving pulses to neighboring Tx lines at the same time through data compensation, thereby reducing the resolution loss of the touch screen. You can prevent it.

1 is a block diagram showing a display device according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a touch screen driving device in FIG. 1.
3 to 5 illustrate various embodiments of a touch screen and a display panel.
6 is a waveform diagram illustrating an antiphase driving pulse of a touch screen according to an exemplary embodiment of the present invention.
7 is a waveform diagram illustrating an example of an antiphase driving pulse.
8 is a waveform diagram showing another example of an antiphase driving pulse.
9 is a circuit diagram showing the Rx driving circuit in detail.
FIG. 10 is an equivalent circuit diagram of a sampling circuit when the switches S11 and S12 shown in FIG. 9 are turned on.
FIG. 11 is an equivalent circuit diagram of a sampling circuit when the switches S21 and S22 shown in FIG. 9 are turned on.
12 is a flowchart illustrating a touch-low data compensation method according to an embodiment of the present invention.
FIG. 13 is a diagram illustrating a case in which an upper sensor node is touched (CASE1) among sensor nodes connected to the Tx lines when simultaneously applying antiphase driving pulses to neighboring Tx lines.
FIG. 14 is a diagram illustrating normal data values obtained in the same case as in FIG. 13 (CASE1).
FIG. 15 is a diagram illustrating a case where a lower sensor node is touched (CASE2) among sensor nodes connected to the Tx lines when simultaneously applying antiphase driving pulses to neighboring Tx lines.
FIG. 16 is a diagram illustrating normal data values obtained in the same case as in FIG. 15 (CASE1).
FIG. 17 illustrates a case in which upper and lower sensor nodes connected to the Tx lines are simultaneously touched (CASE3) when the antiphase driving pulses are simultaneously applied to neighboring Tx lines.
FIG. 18 is a diagram showing normal data values obtained in the same case as in FIG. 17 (CASE3).
19 is a diagram illustrating an example of reference data.
20 is a diagram illustrating an example of normal data.
21 is a diagram illustrating an example of primary compensation data.
22 is a diagram showing the results of the integral calculation of the 1C order compensation data.
FIG. 23 is a diagram illustrating an example of final touch raw data obtained by adding a compensation value to an integration operation result.

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.

1 and 2, a display device according to an exemplary embodiment of the present invention includes a display panel DIS, a display driving circuit, a touch screen TSP, a touch screen driving circuit, and the like.

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), and electrophoretic display devices (Electrophoresis, EPD) can be implemented based on a flat panel display device. In the following embodiments, the liquid crystal display device is described as an example of the flat panel display device, but it should be noted that the display device of the present invention is not limited to the liquid crystal display device.

In the display panel DIS, a liquid crystal layer is formed between two substrates. The lower substrate of the display panel DIS includes a plurality of data lines D1 to Dm and m is a natural number, and a plurality of gate lines (or scan lines) G1 to Gn intersecting the data lines D1 to Dm. , n is a natural number), a plurality of TFTs (Thin Film Transistor) formed at the intersections of the data lines (D1 ~ Dm) and the gate lines (G1 ~ Gn), a plurality for charging the data voltage to the liquid crystal cells And a storage capacitor connected to the pixel electrode and the pixel electrode to maintain the voltage of the liquid crystal cell.

The pixels of the display panel DIS 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 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 and the common voltage applied to the common electrode to adjust the amount of incident light transmitted. The TFTs are turned on in response to gate pulses from the gate lines G1 to Gn to supply a voltage from the data lines D1 to Dm to the pixel electrodes of the liquid crystal cell.

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

A polarizing plate is attached to each of the upper substrate and the lower substrate of the display panel DIS, and an alignment layer for setting the pretilt angle of the liquid crystal is formed on an inner surface of the display panel DIS. A column spacer for maintaining a cell gap of the liquid crystal cell is formed between the upper substrate and the lower substrate of the display panel DIS.

The display panel DIS may be implemented in any known liquid crystal mode such as TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, IPS (In Plane Switching) mode and FFS (Fringe Field Switching) mode.

A backlight unit (not shown) may be disposed on the back of the display panel DIS. The backlight unit is implemented as an edge type or direct type backlight unit to emit light to the display panel DIS.

The display driving circuit includes the data driving circuit 12, the scan driving circuit 14, the timing controller 20, and the like, and writes the video data voltage of the input image to the pixels of the display panel DIS.

The data driving circuit 12 converts the digital video data RGB input from the timing controller 20 into an analog positive / negative gamma compensation voltage and outputs a data voltage. The data voltage is supplied to the data lines D1 to Dm. The scan driving circuit 14 sequentially supplies a gate pulse (or a scan pulse) synchronized with the data voltage to the gate lines G1 to Gn to select a line of the display panel DIS to which the data voltage is written.

The timing controller 20 receives timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal Data Enable, and a main clock MCLK input from an external host system. A scan timing control signal and a data timing control signal for controlling the operation timing of the data driver circuit 12 and the scan driver circuit 14 are generated. The scan timing control signal includes a gate start pulse (GSP), a gate shift clock, a gate output enable signal (GOE), and the like. The data timing control signal includes a source sampling clock (SSC), a polarity control signal (Polarity), a source output enable signal (SOE), and the like.

The touch screen TSP may be bonded to the upper polarizing plate POL1 of the display panel DIS as shown in FIG. 3, or may be formed between the upper polarizing plate POL1 and the upper substrate GLS1 as shown in FIG. 4. In addition, the sensor nodes TSCAP of the touch screen TSP may be formed on the lower substrate in an in-cell type together with a pixel array in the display panel DIS as shown in FIG. 5. In Fig. 3 to Fig. 5, "PIX" means a pixel electrode of a liquid crystal cell, "GLS2" means a lower substrate, and "POL2" means a lower polarizer.

The touch screen TSP includes Tx lines (T1 to Tj, j is a positive integer smaller than n), and Rx lines R1 to Ri and i intersect the Tx lines T1 to Tj, respectively. Integer), and i × j sensor nodes TSCAP formed at intersections of the Tx lines T1 to Tj and the Rx lines R1 to Ri.

The touch screen driving circuit includes a Tx driving circuit 32, an Rx driving circuit 34, a touch controller 30, and the like. The touch screen driving circuit supplies the driving pulses as shown in FIGS. 6 to 8 to the Tx lines T1 to Tj and samples the voltages of the sensor nodes received through the Rx lines R1 to Ri. The touch screen driving circuit converts the sampled voltage of the sensor node into digital data through an analog-to-digital converter (ADC) to output touch raw data. The Tx driving circuit 32 and the Rx driving circuit 34 may be integrated in one read-out IC (ROIC).

The Tx driving circuit 32 sets Tx channels for simultaneously outputting antiphase driving pulses in response to the Tx setup signal SUTx input from the touch controller 30. The Tx driving circuit 32 simultaneously supplies the antiphase driving pulses A and B to the neighboring Tx lines T1 and T2 through the Tx channels as shown in FIG. 6.

If j sensor nodes TSCAP are connected to one Tx line, the driving pulses A and B are supplied to the Tx line j consecutively, and then the driving pulses are continuously supplied to the next Tx line in the same manner. Can be. In another embodiment, if j sensor nodes TSCAP are connected to one Tx line, driving pulses A and B may be continuously supplied to the Tx line (j / SUN +1) times. Here, SUN (Sensing Unit Number) means the number of sensor nodes that are simultaneously received through N (N is a natural number less than or equal to 2) Rx lines. The SUN is set by the Rx setup signal SURx generated from the touch controller 30, and the Rx driving circuit 34 simultaneously sets N Rx channels in response to the Rx setup signal SURx and the Rx channels. It receives the voltage of the sensor nodes through the connected N Rx lines. 1 in “(j / SUN +1)” means that drive pulses A and B are supplied to the Tx line once more to receive sensor nodes on the remaining Rx channels when the remainder of j / SUN is not zero. .

In order to accumulate the voltage of the sensor node TSCAP in the sampling capacitor (Cc of FIG. 9) of the Rx driving circuit 34 more than two times to increase the charge amount of the sampling capacitor Cc, the driving pulse is the Tx lines T1. Tj) may be repeatedly supplied two or more times.

The Rx driving circuit 34 sets the Rx channel in response to the Rx setup signal SURx input from the touch controller 30 and receives the sensor node voltage through the Rx lines R1 to Ri connected to the set Rx channel. . The Rx line through which the sensor node voltage is received is an Rx line electrically coupled with the Tx line to which a driving pulse is applied. The Rx driving circuit 34 charges the sensor node voltage received for each driving pulse to the sampling capacitor Cc in response to the Rx sampling clock SRx of the touch controller 30 to sample the sensor node voltage. The Rx driving circuit 34 converts the sampled sensor node voltage into digital data through the ADC and transmits the digital data to the touch controller 30.

The touch controller 30 is connected to the Tx driving circuit 32 and the Rx driving circuit 34 through an interface such as an I 2 C bus, a serial peripheral interface (SPI), a system bus, or the like. The touch controller 30 supplies the setup signals SUTx and SURx to the Tx driving circuit 32 and the Rx driving circuit 34 to set the Tx channel to which the driving pulse is output and to set the Rx channel to receive the sensor node voltage. do. The touch controller 30 supplies an Rx sampling clock SRx for controlling the switches of the sampling circuit built in the Rx driving circuit 34 to the Rx driving circuit 34 to provide sampling timing of the sensor node voltage and operation of the ADC. Control the timing.

The touch controller 30 analyzes the touch furnace data input from the Rx driver circuit 34 by using a known touch recognition algorithm, and estimates coordinate values of the touch furnace data whose changes before and after touch are larger than a predetermined reference value. The touch coordinate data HIDxy including the coordinate value is output. Touch row data whose changes before and after the touch are greater than a predetermined reference value are estimated as touch (or proximity) inputs. The touch coordinate data HIDxy output from the touch controller 30 is transmitted to an external host system. The touch controller 30 may be implemented as a micro controller unit (MCU).

The host system may be connected to an external video source device such as a navigation system, a set top box, a DVD player, a Blu-ray player, a personal computer (PC), a home theater system, a broadcast receiver, a phone system, Video data can be input from the device. The host system includes a system on chip (SoC) incorporating a scaler to convert input image data from an external video source device into a format suitable for display on the display panel DIS. In addition, the host system executes an application program associated with the coordinate value of the touch data input from the touch controller 30.

FIG. 7 is a waveform diagram illustrating an example of anti-phase driving pulses A and B shown in FIG. 6. 8 is a waveform diagram illustrating another example of the antiphase driving pulses A and B shown in FIG. 6.

Referring to FIG. 7, the Tx driving circuit 32 supplies a driving pulse A to the first Tx line T1 under the control of the touch controller 30, and has a phase difference of 180 ° with respect to the driving pulse A. The driving pulse B is supplied to the second Tx line T2. Therefore, whenever the touch screen TSP is scanned, antiphase driving pulses A and B are simultaneously supplied to the neighboring first and second Tx lines T1 and T2.

The driving pulses A and B may be generated as pulses swinging between 0 V and the positive voltage Vh as shown in FIG. 7. Also, although not shown, the driving pulses A and B may be generated as pulses swinging between a negative voltage lower than 0V and a positive voltage higher than 0V.

The Rx driving circuit 34 sets an Rx channel to receive the sensor node voltage in synchronization with at least one of the antiphase driving pulses A and B supplied to the first and second Tx lines T1 and T2. The Rx driving circuit 34 simultaneously receives voltages of sensor nodes connected to two neighboring Tx lines on the touch screen TSP through the Rx line connected to the configured Rx channel. The voltage Vout of the sensor nodes received at the Rx driving circuit 34 is equal to two sensor nodes (equivalently) as can be seen in the definitions of FIGS. 9, 13, 15, 17, and Equation 1. , At a relative rate distributed to the capacitors). The Rx driving circuit 34 samples the received sensor node voltage and converts it into digital data.

The Tx driving circuit 32 supplies the driving pulse A to the second Tx line T2 under the control of the touch controller 30 and simultaneously supplies the driving pulse B having a phase difference of 180 ° with respect to the driving pulse A. Supply to Tx line T3. The driving pulse A is supplied to the second Tx line T2 immediately after the driving pulse B is supplied. Accordingly, the driving pulses A and B in phases with each other are simultaneously supplied to the second and third Tx lines T2 and T3. The Rx driving circuit 34 sets an Rx channel to receive the sensor node voltage in synchronization with at least one of the antiphase driving pulses A and B supplied to the second and third Tx lines T2 and T3. The Rx driver circuit 34 simultaneously receives a voltage Vout of sensor nodes connected to neighboring Tx lines on a touch screen TSP through an Rx line connected to a set Rx channel, samples the received sensor node voltage, and digitally. Convert to data.

The driving pulse A is supplied to the second to j-1 Tx lines T2 to Tj-1 immediately after the driving pulse B is supplied. Only the driving pulse B is supplied to the j th Tx lines Tj. The Tx driving circuit 32 supplies the driving pulse A to the j-1 th Tx line Tj-1 under the control of the touch controller 30, and has a phase difference of 180 degrees with respect to the driving pulse A. B is supplied to the j th Tx line Tj. Accordingly, the driving pulses A and B of antiphase are simultaneously supplied to the j-th and j-th Tx lines Tj-1 and Tj. The Rx driving circuit 34 receives the sensor node voltage in synchronization with at least one of the antiphase driving pulses A and B supplied to the j-1 and j th Tx lines Tj-1 and Tj. Set. The Rx driver circuit 34 simultaneously receives a voltage Vout of sensor nodes connected to neighboring Tx lines on a touch screen TSP through an Rx line connected to a set Rx channel, samples the received sensor node voltage, and digitally. Convert to data.

Referring to FIG. 8, the Tx driving circuit 32 supplies a driving pulse A to the first Tx line T1 under the control of the touch controller 30, and has a phase difference of 180 ° with respect to the driving pulse A. The driving pulse B is supplied to the second Tx line T2. Accordingly, the driving pulses A and B in phase out of each other are simultaneously supplied to the neighboring first and second Tx lines T1 and T2. The Rx driving circuit 34 simultaneously receives the voltage Vout of the sensor nodes connected to the first and second Tx lines, samples the received sensor node voltage, and converts the received sensor node voltage into digital data.

The driving pulse A may be generated as a pulse swinging between 0 V and the positive voltage Vh, and the driving pulse B may be generated as a pulse swinging between 0 V and the negative voltage Vl. In FIG. 8, since the voltage difference between the positive voltage Vh and the negative voltage Vl is larger than the driving pulse voltage difference in FIG. 7, the positive voltage Vh in FIG. 8 can be sufficiently lowered.

The Tx driving circuit 32 supplies the driving pulse A to the second Tx line T2 under the control of the touch controller 30 and simultaneously supplies the driving pulse B having a phase difference of 180 ° with respect to the driving pulse A. Supply to Tx line T3. The driving pulse A is supplied to the second Tx line T2 immediately after the driving pulse B is supplied. Therefore, the driving pulses A and B in phase out of each other are simultaneously supplied to the neighboring second and third Tx lines T2 and T3. The Rx driving circuit 34 simultaneously receives the voltage Vout of the sensor nodes connected to the second and third Tx lines, samples the received sensor node voltage, and converts the received sensor node voltage into digital data.

The driving pulse A is supplied to the second to j-1 Tx lines T2 to Tj-1 immediately after the driving pulse B is supplied. Only the driving pulse B is supplied to the j th Tx line Tj. The Tx driving circuit 32 supplies the driving pulse A to the j-1 th Tx line Tj-1 under the control of the touch controller 30, and has a phase difference of 180 degrees with respect to the driving pulse A. B is supplied to the j th Tx line Tj. Therefore, the driving pulses A and B in phase out of each other are simultaneously supplied to the neighboring j-1 and jth Tx lines Tj-1 and Tj. The Rx driving circuit 34 simultaneously receives the voltage Vout of the sensor nodes connected to the j-th and j-th Tx lines, samples the received sensor node voltage, and converts the received sensor node voltage into digital data.

9 to 11 are diagrams showing the sampling circuit of the Rx driver circuit 34 and its operation in detail.

9 to 11, the sampling circuit of the Rx driving circuit 34 includes the first to fourth switches S11 to S22, the sensing capacitor CS, the sampling capacitor Cc, and an operation amplifier. OP) and the like. The sensing capacitor CS is connected between the first node n1 and the second node n2. The sampling capacitor Cc is connected between the third node n3 and the output terminal of the operational amplifier OP. The third node n3 is connected to the inverting input terminal of the operational amplifier OP. The non-inverting input terminal of the operational amplifier OP is connected to the ground voltage source GND, and the output terminal of the operational amplifier OP is connected to the input terminal of the ADC.

Vertically neighboring sensor nodes C1 and C2 are connected to an input terminal of the first switch S11 through an Rx line R (p), where p is a natural number less than or equal to i. The output terminal of the first switch S11 is connected to the first node n1. The first switch S11 is turned on at a time t1 in response to the first Rx sampling clock S1 (t1). The first Rx sampling clock S1 (t1) is synchronized with the high logic voltage of the drive pulse A supplied to the qth (q is a positive integer less than or equal to j-1) Tx line T (q). The second switch S12 is connected between the second node n2 and the ground voltage source GND. The second switch S12 is turned on at a time t1 in response to the first Rx sampling clock S1 (t1).

The first and second switches S11 and S12 are turned on every t1 time in synchronization with the high logic voltage of the driving pulse A shown in FIGS. 6 to 9, and the sensor node voltage is applied to the sensing capacitor CS as shown in FIG. 10. Charge (Vout). On the other hand, the first and second switches S11 and S12 are turned off every t2 times in synchronization with the low logic voltage of the driving pulse A shown in FIGS. 6 to 9, and Rx as shown in FIG. 11. The current path between the input terminal of the driving circuit 34 and the first node n1 is opened, and the current path between the second node n2 and the ground voltage source GND is opened.

The third switch S21 is connected between the first node n1 and the ground voltage source GND. The third switch S21 is turned on every t2 time in response to the second Rx sampling clock S2 (t2). The second Rx sampling clock S2 (t2) is synchronized with the low logic voltage of the driving pulse A supplied to the qth Tx line T (q). The fourth switch S22 is connected between the second node n2 and the third node n3. The fourth switch S22 is turned on in response to the second Rx sampling clock S2 (t2).

The third and fourth switches S21 and S22 are turned off at the time t1, and the current path between the first node n1 and the base voltage source GND, the second node n2 and the third node as shown in FIG. Open the current path between nodes n3. On the other hand, the third and fourth switches S21 and S22 are turned on every t2 time to connect the sensing capacitor CS to the sampling capacitor Cc and to the sampling capacitor CS as the voltage of the sensing capacitor CS as shown in FIG. 11. Charge (Cc).

The ADC converts the voltage of the sampling capacitor Cc into digital data.

In the prior art, the sensor node voltage Vout received through the Rx line R (p) was the voltage of the first sensor node C1 connected to the qth Tx line T (q). In the related art, when the voltage of the first sensor node C1 is referred to as V1, the noise α caused by the influence of the driving signal of the display panel is added to the V1, thereby sensing the V1 to α.

In contrast, in the present invention, since the sensor node voltage Vout received through the Rx line Ri is distributed to vertically neighboring sensor nodes C1 and C2 as shown in FIG. When there is no α, it can be expressed as Equation 1.

Here, Vin is the voltage of the drive pulse A.

로 표현될 수 있다. 따라서, 표시패널의 구동 신호 영향으로 인하여 센서 노드 전압에 노이즈가 혼입되면, 본 발명의 터치 스크린은 노이즈의 영향을 β/(α+β) 만큼 줄일 수 있다. 일반적으로, α와 β는 위상이 거의 동일하고 크기가 거의 같은 노이즈 성분이다. 이를 고려할 때 본 발명의 터치 스크린(TSP)은 표시패널의 구동 신호 영향으로 인한 노이즈 영향을 종래 기술에 비하여 대략 1/2 정도 줄일 수 있다.Due to the influence of the display panel, when noise is mixed in the first and second sensor nodes C1, the noise component is added to the denominator in Equation 1, thereby reducing the noise component as compared with the prior art. For example, when the noise added to C1 is α and the noise added to C2 is β in Equation 1, when C1 of the vertically neighboring sensor nodes is touched.

It can be expressed as. Therefore, when noise is mixed into the sensor node voltage due to the influence of the driving signal of the display panel, the touch screen of the present invention can reduce the influence of noise by β / (α + β). In general, alpha and beta are noise components that are nearly equal in phase and approximately equal in magnitude. In consideration of this, the touch screen (TSP) of the present invention can reduce the noise effect due to the driving signal influence of the display panel by about 1/2 compared to the prior art.

Meanwhile, as described above, when the sensor node is sensed by applying anti-phase driving pulses to the sensor nodes C1 and C2 that are vertically neighboring, the total number of lines of the touch screen TSP is j-1. Sensor nodes may be sensed in four lines. Hereinafter, a touch furnace data compensation method for obtaining data on touch nodes of sensor nodes in j lines based on the sensing results of j-1 lines will be described.

In FIG. 9, reference numeral 100 denotes a data compensator. The data compensator 100 performs the data compensation method as shown in FIGS. 12 to 23 to apply the anti-phase driving pulses A and B to neighboring Tx lines to generate the data missing when generating the sensor nodes. Generate based on the integral operation on the data. The data (TDATA) with the final touch outputted from the data compensating unit (100) is analyzed by the touch recognition algorithm.

12 is a flowchart illustrating a touch-low data compensation method according to an embodiment of the present invention.

Referring to FIG. 12, in the touch raw data compensation method, the inverse driving pulses A and B are sequentially performed on the Tx lines T1 to Tj of the touch screen by initializing the touch screen TSP and the touch screen driving circuit. And the sensor node voltage is received through the Rx lines R1 to Ri to scan the touch screen TSP. As a result of scanning this touch screen TSP, touch raw data when no touch (or proximity) input is obtained from i x (j-1) sensor nodes of the touch screen. (S1 and S2) Hereinafter, The touch furnace data obtained in the steps S1 and S2 is defined as "reference data".

The digital value of the reference data may be “2000” as shown in FIG. 19. Here, "2000" is assumed to be a digital value of the voltage received from the sensor nodes in the case of normal without noise for convenience of understanding. Since reference data obtained from the touch screen TSP is i × (j−1) pieces, the reference data is insufficient by one line of reference data compared to the number of sensor nodes of the touch screen. In the following, it is assumed that i = 43 and j = 27. The touch raw data compensation method adds one line of dummy data to the reference data. The dummy data are not obtained from the touch screen TSP and are given a value '0' stored in advance in the internal memory of the Rx driving circuit 34 or the ROIC (Read-out IC). The dummy data is defined as reference data of the first uppermost line of the touch screen TSC. 43 × 27 reference data RDATA including dummy data as shown in FIG. 19 are stored in a memory. The memory may be an internal memory of the Rx driving circuit 34 or a read-out IC (ROIC).

In the touch furnace data compensation method, anti-phase driving pulses A and B are sequentially applied to the Tx channels T1 to Tj to scan the touch screen TSP. The touch raw data compensation method may be performed by calculating touch raw data (hereinafter referred to as "normal data (NData)") obtained when a touch (or proximity) input of a scanning result of the touch screen (TSP) is detected and prestored reference data. The first compensation data CDATA is calculated by performing a difference operation as shown in Equation 2 (S3 and S4).

The normal data NData has a lower value or higher value than the reference data according to the position of the touch screen TSP. This will be described in detail with reference to FIGS. 13 to 18.

CASE1

13 and 14, when a finger (or conductive material) touches the first sensor node C1 connected to the qth Tx line T (q), the capacitance value of the first sensor node C1 is increased due to the finger. Lowers. Here, it is assumed that the sensor node change amount before and after the touch is "1000" as the digital value. As a result, if C1 is reduced by "1000" in Equation 1, the normal data obtained from the touched sensor node is lower than the reference data RData as shown in FIG.

CASE1 includes sensor nodes connected to the first Tx line T1 when anti-phase driving pulses A and B are applied to the first Tx line T1 and the second Tx line T2, as shown in IN1 and IN3 of FIG. 20. When the sensor nodes connected to the 26th Tx line T26 are touched when the antiphase driving pulses A and B are applied to the 26th Tx line T26 and the 27th Tx line T27. Is generated.

In FIG. 20, normal data NData of IN1 or IN3 is a sensor node received from a third Rx line R3 when antiphase driving pulses A and B are applied to the first and second Tx lines T1 and T2. It is a digital value calculated by the amount of change in voltage. The normal data (NData) for IN1 or IN3 is RData-1000 = 1000.

CASE2

15 and 16, when a finger (or conductive material) is touched on the second sensor node C2 connected to the q + 1 Tx line T (q + 1), the second sensor node C2 is caused by the finger. The capacity value of is lowered. It is assumed that the sensor node change amount before and after the touch is "1000" as the digital value. As a result, if C2 is decreased by "1000" in Equation 1, normal data obtained from the touched sensor node is higher than reference data RData as shown in FIG.

CASE2 corresponds to IN2 in FIG. 20, and normal data NData for IN2 is RData + 1000 = 3000. When the antiphase driving pulses A and B are applied to the 26th Tx line T26 and the 27th Tx line T27, the normal data generated from the sensor nodes connected to the 27th Tx line T27 is only CASE 2. Obtained. This is because there is no Tx line below the twenty-seventh Tx line T27.

CASE3

CASE3 is a first sensor node C1 connected to the qth Tx line T (q) and a second sensor node connected to the q + 1 Tx line T (q + 1) as shown in FIGS. 17 and 18. This is a case where a finger (or a conductive material) is touched at the same time as C2. CASE 3 is the qth Tx line T (q) when antiphase driving pulses A and B are applied to the q-1 Tx line T (q-1) and the qth Tx line T (q). Inverse to the normal data value (CASE2), the q + 1 Tx line (T (q + 1)) and the q + 2 Tx line (T (q + 2)) generated when the sensor nodes connected to Normal data having their median value between the normal data values CASE2 generated when the sensor nodes connected to the q + 1 Tx line T (q + 1) are touched when the phase driving pulses A and B are applied. Is generated. The median value is similar to the reference data RDATA.

Referring to FIG. 12, the touch furnace data compensation method of the present invention integrates primary compensation data CDATA obtained through steps S1 to S4 along the Y-axis direction (or Rx line direction) to generate final touch furnace data. (S5) The integral calculation method begins to accumulate the difference between the uppermost data and the neighboring data along the Y axis of the touch screen TSP and accumulates the difference value of the neighboring data from the lowermost data. For example, after the first integration result (I2 in FIG. 22) is calculated as N 2 -N 1 = −1000 in the first compensation data as illustrated in FIG. 21, the second integration result (N in FIG. 22 is shown in FIG. 22). I3) is calculated. In the same way, after the 24th integral result (I25 in FIG. 22) is calculated with N25-I24 = 0, the 25th integral result (I26 in FIG. 22) is calculated with N26-I25 = 0, and then N27-I26 = At -1000, the 26th integration result (I27 of FIG. 22) is calculated.

The touch raw data compensation method compensates the y-axis normal data of the touch screen TSP by adding a compensation value to the integration results obtained in step S5. (S6) Here, the y-axis normal data is the y-axis of the touch screen TSP. Normal data of sensor nodes connected to the Rx line formed along the direction. The compensation value is automatically set so that the minimum value is '0' among the integration results arranged along the Rx line and is independently determined for each Rx line. The compensation value to be added to the integration results arranged in the Rx line direction is the same. The compensation value to be added to the integration results arranged in the x-axis direction may vary. For example, the first compensation value added to the integration results arranged along the first Rx line R1 and the second compensation value added to the integration results arranged along the second Rx line R2 are each Rx line. Since the minimum value of the first Rx line R1 and the minimum value of the second Rx line R2 are different from each other, the result is determined according to the integration result of the minimum value.

For example, in FIG. 22, the minimum value among the integration results arranged along the third Rx line R3 is −1000. The compensation value to be added to the integration results of the third Rx line R3 is automatically determined as a value such that the minimum value -1000 can be zero, that is, -1000 + y = 0 to y = 1000 so that the third Rx line Rx Is added to all integration results arranged along the y-axis. As a result, the final touch row data TDATA generated by the touch furnace data compensation method is generated in the same number as the number of sensor nodes formed in all lines of the touch screen as shown in FIG. 23.

The touch recognition algorithm estimates the coordinate value of the touch (or proximity) input position by analyzing the final touch data obtained in step S6.

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.

DIS: Display panel TSP: Touch screen
12: data driving circuit 14: scan driving circuit
20: timing controller 30: touch controller
32: Tx driving circuit 34: Rx driving circuit

Claims (9)

A touch screen including Tx lines, Rx lines intersecting the Tx lines, and sensor nodes formed at an intersection of the Tx lines and the Rx lines;
A Tx driving circuit which sequentially supplies driving pulses to the Tx lines, and supplies driving pulses that are out of phase with each other to neighboring Tx lines;
An Rx driving circuit sampling a voltage of a sensor node received through the Rx lines coupled with the Tx lines and converting the sampled voltage into digital data;
Immediately after initialization of the touch screen, reference data including the digital data and preset dummy data obtained as a result of the scanning of the touch screen are stored in a memory, and the normal data generated after the touch input on the touch screen is stored in the memory. A data compensator for generating first compensation data by subtracting reference data, integrating the first compensation data, adding a compensation value, and generating final touch data; And
And a touch controller which controls the Tx driving circuit and the Rx driving circuit, and estimates coordinates of the touch input position by analyzing the final touch furnace data with a preset touch recognition algorithm. The method of claim 1,
The Tx drive circuit,
And a first driving pulse supplied to the first Tx line, and a second driving pulse which is in phase with respect to the first driving pulse to the second Tx line. The method of claim 1,
The integral operation of the data compensation unit is
In the first compensation data arranged vertically along the y axis of the touch screen, a difference between the first and second first compensation data that are vertically neighboring is calculated as a first integration result, and in the third first compensation data. And calculating a second integration result by subtracting the first integration result to accumulate the difference between neighboring primary compensation data. The method of claim 1,
And each of the dummy data is set to '0'. The method according to claim 1 or 3,
The compensation value is
Independently determined for each Rx line,
The i < th > compensation value to be added to the i < th > (i is natural number) integral results arranged along the Rx line is added equally to the integral results arranged along the ith Rx line,
When the i th compensation value is added to the integration results arranged along the i th Rx line, the minimum value of the integration results arranged along the i th Rx line is changed to '0'. . A method of driving a touch screen including a touch screen including Tx lines, Rx lines crossing the Tx lines, and sensor nodes formed at an intersection of the Tx lines and the Rx lines,
Supplying driving pulses sequentially to the Tx lines, and supplying driving pulses that are out of phase to neighboring Tx lines;
Sampling a voltage at a sensor node received over the Rx lines coupled with the Tx lines and converting the sampled voltage into digital data;
Storing reference data including the digital data and preset dummy data obtained as a result of scanning the touch screen in a memory immediately after initialization of the touch screen;
Generating first compensation data by subtracting the reference data from normal data generated after a touch input on the touch screen;
Integrating the first compensation data and adding a compensation value to generate final touch data; And
And estimating coordinates of a touch position by analyzing the final touch data using a preset touch recognition algorithm. The method according to claim 6,
Integrating the first compensation data and adding the compensation value to generate the final touch data,
In the first compensation data arranged vertically along the y axis of the touch screen, a difference between the first and second first compensation data that are vertically neighboring is calculated as a first integration result, and in the third first compensation data. And calculating a second integration result by subtracting the first integration result to accumulate the difference between neighboring primary compensation data. The method according to claim 6,
And each of the dummy data is set to '0'. The method according to claim 6 or 7,
The compensation value is
Independently determined for each Rx line,
The i < th > compensation value to be added to the i < th > (i is natural number) integral results arranged along the Rx line is added equally to the integral results arranged along the ith Rx line,
When the i th compensation value is added to the integration results arranged along the i th Rx line, the minimum value of the integration results arranged along the i th Rx line is changed to '0'. .

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