KR20170049668A - Display with touch screen and driving circuit - Google Patents

Abstract

The present invention relates to a display device having a touch screen and a driving circuit thereof. The display device having a touch screen comprises: a plurality of integrated circuits (IC)s which amplify and integrate signals of touch sensors, convert the signals into digital data, and output touch raw data; and a micro-control unit (MCU) which is connected to the ICs through a serial peripheral interface (SPI), analyzes the touch raw data from the ICs, and outputs coordinate information of each touch input. When a signal of a master input slave output (MISO) channel among the SPI channels is toggled in an SPI standby condition, the micro-control unit transmits a command and dummy data through a master output slave input (MOSI) channel in synchronization with a clock and, subsequently, receives the touch raw data from the ICs through the MISO channel. Accordingly, GPIO wiring can be removed by implementing SPI communications between the MCU and a plurality of the ICs (an ROIC or an SRIC) with only an SPI communications channel without a GPIO channel.

Description

DISPLAY WITH TOUCH SCREEN AND DRIVING CIRCUIT [0002]

The present invention relates to a display device having a touch screen in which touch sensors are embedded in a pixel array and a driving circuit thereof.

A user interface (UI) enables a user (a user) to communicate with various electric or electronic devices, allowing the user to easily control the device as desired. Representative examples of the 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 functions. 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.

The touch UI implements a touch screen on the display panel to sense the touch input and transmit the user input to the electronic device. Touch UI is essential for portable information devices such as smart phones, and is being applied to notebook computers, computer monitors, and home appliances.

Recently, a method of implementing a touch screen using a technique of incorporating touch sensors in a pixel array of a display panel (hereinafter referred to as "In-cell touch sensor") has been applied. The touch sensors can be implemented as a capacitive type touch sensor that senses a touch based on a change in capacitance before and after the touch.

Incelel touch sensor technology can install touch sensors on the display panel without increasing the thickness of the display panel. The in-line touch sensor technology can utilize the electrodes connected to the pixels of the display panel as the touch sensor electrodes C1 to C4. 1, a common electrode for supplying a common voltage Vcom to the pixels of the liquid crystal display device may be divided into the touch sensor electrodes C1 to C4. The sensor wirings SL are connected to the touch sensor electrodes C1 to C4. Since the touch sensors Cs are embedded in the pixel array of the display panel 100, the touch sensors Cs are coupled to the pixels through the parasitic capacitance. In order to reduce the mutual influence due to the coupling of the pixels and the touch sensors Cs, the in-cell touch sensor technique time-divides one frame period into a display period and a touch sensing period. The in-line touch sensor technology supplies a common voltage Vcom, which is a reference voltage of a pixel, to the touch sensor electrodes C1 to C4 during a display period, and senses the touch input by driving the touch sensor during a touch sensing period.

The display device includes a data driver for supplying a data voltage to the data lines of the display panel, a gate driver (or a scan driver) for supplying a gate pulse (or a scan pulse) to the gate lines of the display panel, And a touch sensing unit for sensing the touch sensing unit.

The touch sensing unit may include a touch ROIC (read out integrated circuit) and a micro control unit (MCU). The ROIC detects the capacitance change of the touch sensor based on the signal change of the sensor wiring and converts it into digital data. The ROIC transmits the digital data to the MCU as touch data (Touch Raw Data). The MCU includes an arithmetic logic circuit for analyzing the touch data. The MCU compares the data with a preset threshold value by touching and judges the data exceeding the threshold value as the touch input. The MCU outputs a touch report including an identification code (ID) for distinguishing coordinate information of each touch input position and each touch input.

ROIC and MUC can communicate data through SPI (Serial Peripheral Interface) as shown in FIG. 2, the SPI master element is the MCU 11, and the SPI slave elements are the ROICs 21 and 22. SPI is a synchronous communication using four wires in series. The SPI is used for communication between the MCU 11 and a peripheral device such as a sensor or a memory. The SPI uses the Master / Slave configuration. The communication channel of the SPI includes SCLK (Serial Clock), MOSI (Master Output Slave Input), MISO (Master Input Slave Output) and CS (Slave Select or Chip Enable). In Fig. 1, MISO is dedicated data input of the master device and dedicated data output of the slave device in SPI communication. MOSI is a dedicated data input channel of the master device and a slave device for SPI communication. CS is a channel for selecting a slave device in SPI communication. The master device selects a slave device to receive data using CS. SCLK is a serial clock that is synchronized with the data.

A general purpose input-output (GPIO) channel is connected between the MCU 11 and the ROICs 21 and 22. The ROICs 21 and 22 transmit to the MCU through the GPIO channel to inform the MCU 11 that the ROICs are ready to transmit touch data.

The MCU 11 receives a signal indicating that the touch data is ready to be transmitted from the ROICs 21 and 22, and receives the touch data from the ROICs 21 and 22 through the MISO channel according to the SPI communication procedure.

In the SPI communication, the master device and the slave device operate in the same manner as a shift register and transmit data. According to the SCLK, when dummy data is transmitted on the MOSI channel by one bit per clock timing of the SCLK from the master device to the slave device, the slave device synchronizes the data with the MISO channel by one bit for every SCLK clock timing, Lt; / RTI >

For the SPI communication between the MCU 11 and the ROICs 21 and 22, in addition to the SPIC communication channels, a further number of GPIO channels is required as the number of ROICs. This makes it difficult to reduce the number of wires between the MCU 11 and the ROICs 21 and 22, and the waiting time before the SPI communication becomes long.

The present invention provides a display device having a touch screen capable of simplifying a communication interface of touch data and a driving circuit thereof.

A display device of the present invention includes a display panel having a plurality of touch sensors connected to data lines and gate lines, the display panel having a plurality of touch sensors connected to the pixels, A plurality of display drivers for amplifying and integrating the signals of the touch sensors during the touch sensing period allocated during the display periods within the one frame period, converting the signals into digital data, And a microcontroller unit (MCU) connected to the integrated circuits through the SPI and analyzing data by a touch from the integrated circuits to output coordinate information of each of the touch inputs.

When the micro control unit toggles a signal of a MISO channel among the SPI channels in an SPI standby state, it transmits commands and dummy data through a MOS (Master Output Slave Input) channel in synchronization with a clock, And receives data from the integrated circuits through the channel via the touch.

The driving circuit of the display device includes a plurality of slave devices for amplifying and integrating the signals of the touch sensors and converting the signals into digital data to output data by touching; And a master device connected to the slave devices through the SPI to analyze coordinate data received from the slave devices and output coordinate information of each of the touch inputs.

When the signal of the MISO channel is toggled among the SPI channels in the SPI standby state, the master device transmits command and dummy data through the MOSI channel in synchronization with the clock to transmit data from the slave devices through the MISO channel .

The GPIO wiring can be removed by implementing the SPI communication between the MCU of the present invention and a plurality of ICs (ROIC or SRIC) with only a SPI communication channel without a GPIO channel. Accordingly, the present invention can simplify the communication interface of the touch data by efficiently implementing the SPI communication procedure by optimizing the SPI communication channel by reducing the wiring required for the SPI communication between the MCU and the ICs.

1 is a plan view showing a touch electrode pattern of a touch sensor and a touch sensing unit.
2 is a diagram illustrating an example in which an MCU and a plurality of ROICs are connected to each other via an SPI interface.
3 is a diagram illustrating an interface between a plurality of ROICs according to an embodiment of the present invention.
4 is a waveform diagram showing a communication method of the SPI interface shown in FIG.
5 is a diagram showing an SPI processing unit of the MCU.
6 is a waveform diagram showing a start signal of the MCU and corresponding SPI data input / output.
7 and 8 are block diagrams showing a display device according to an embodiment of the present invention.
9 is a plan view showing SRICs having a touch sensing unit and a data driver.
10 is a view showing a plane arrangement of the in-cell type touch sensors and a circuit configuration of the touch sensing unit.
11 is a waveform diagram showing a driving signal of a display device according to an embodiment of the present invention.
12 to 14 are diagrams showing examples of a touch data transmission method using SPI in various insole touch sensing methods.

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 implemented as a flat panel display device such as a liquid crystal display (LCD), an organic light emitting display (OLED) display, or the like. In the following embodiments, a liquid crystal display device will be described as an example of a flat panel display device, but the present invention is not limited thereto. For example, the display device of the present invention may be any display device to which the in-line touch sensor technology is applicable.

The touch sensor of the present invention can be implemented by a capacitive type touch sensor that can be embedded in a pixel array, for example, a mutual capacitance sensor or a self capacitance sensor. Hereinafter, the touch sensor will be described with reference to the magnetic sensor, but the present invention is not limited thereto.

3 is a diagram illustrating an interface between the MCU 50 and a plurality of ROICs 61 and 62 according to an embodiment of the present invention. 4 is a waveform diagram showing a communication method of the SPI interface shown in FIG. In FIG. 3, the ROICs 61 and 62 are illustrated as two, but are not limited thereto. For example, the MCU 50 is connected to N (N is a positive integer equal to or greater than two) ROICs 61 and 62 via the SPI.

3 and 4, the MCU 50 is connected to a plurality of ROICs 61 and 62 via SPI communication channels. The MCU 50 operates as an SPI master. The ROICs 61 and 62 operate as SPI slaves. The communication channels of the SPI include SCLK, MOSI, MISO, and CS. The CS channel may be set to a number equal to the number of ROICs in order to select each of the IC chips.

The ROICs 61 and 62 toggle the MISO channel signal when the preparation for transmission of the touch data is completed. When the MISO channel signal is toggled to 1 (or a high level) in the standby state of the SPI, the MCU 11 detects the toggle of the MISO channel signal and starts transmitting the instructions and dummy data synchronized with the clock timing with the SCLK to the MOSI channel through MOSI do. When the dummy data is received through the MOSI channel, the ROICs 61 and 62 output the touch data for a predetermined amount of data through the MISO channel to start transmitting the touch data. Here, the predetermined amount of data is equal to the amount of dummy data. The MCU 50 receives touch data from the ROICs 61 and 62 via the MISO channel.

When CS = 1 (or high level), the SPI is in the standby state. Since the SCLK and MOSI channel data are not generated in the waiting state, the ROICs 61 and 62 can not transmit the touch data in the standby state. In the example of FIG. 4, the instruction may include a memory address instruction, a memory read instruction, and the like. The dummy data is not any meaningful data including information but an arbitrary bit string for deriving the touch data transmission of the ROICs 61 and 62.

Since the MCU 50 and ROICs 61 and 62 of the present invention perform SPI communication without a GPIO channel, a GPIO channel is not required between them. Therefore, the present invention can efficiently implement the SPI communication procedure by optimizing the SPI communication channel by reducing the wiring required for the SPI communication between the MCU 50 and the ROICs 61 and 62.

The MCU 50 of the present invention includes a start signal generator 503 as shown in FIG. 5 in order to generate an SPI start command when the MISO is toggled in the standby state.

5 is a diagram showing an SPI processing unit of the MCU 50. As shown in FIG. 6 is a waveform diagram showing a start signal of the MCU and corresponding SPI data input / output.

5 and 6, the SPI processing unit of the MCU 50 includes an SPI control unit 501, an SPI memory 502, and a start signal generation unit 503.

The start signal generation unit 503 generates a start signal when the MISO channel signal is 1 in the standby state where CS = 1. Therefore, the start signal is generated when the MISO is toggled to 1 (= high level) in the standby state. The start signal generator 503 may be implemented as a multiplexer (MUX) that selects a MISO channel signal according to the CS signal and transmits the selected MISO channel signal to the SPI controller 501.

The SPI control unit 501 is enabled when the start signal is inverted to a high level to activate the SPI communication channel. In response to the start signal, the SPI control unit 501 inverts the CS channel to 0 (= low level) to select the ROIC, generates the SCLK, and controls the SPI memory 502 to transmit the instruction and dummy data . The SPI memory 501 outputs the dummy data through the MOSI channel in synchronization with the clock timing of the SCLK under the control of the SPI controller 501, and simultaneously receives the touch data through the MISO channel. The SPI memory 502 performs parallel input serial output (PISO) on the MOSI channel. The SPI memory 502 then performs serial input parallel output (SIPO) on the MISO channel.

7 and 8 are block diagrams showing a display device according to an embodiment of the present invention.

7 and 8, the display apparatus of the present invention includes a display panel 100, a display driving circuit, a touch sensing unit 110, and the like.

One frame period of the display panel 100 may be time-divided into one or more display periods and one or more touch sensing periods. The screen (pixel array) of the display panel 100 is time-divisionally driven to two or more blocks B1 to BM. The blocks B1 and B2 need not be physically divided. FIG. 7 shows an example in which the screen of the display panel 100 is divided into two blocks B1 and B2. FIG. 3 shows an example in which the screen of the display panel 100 is divided into blocks M (M is a positive integer of 3 or more) (B1 to BM). The blocks of the display panel 100 are time-divided through the touch sensing period. For example, during the first display period, after the pixels 11 of the first block B are driven and the current frame data is written to the pixels 11, the touch input is sensed during the first touch sensing period . Following the first touch sensing period, during the second display period, the pixels 11 of the second block B are driven and the current frame data is written to the pixels 11 thereof.

The screen of the display panel 100 includes a pixel array in which an input image is reproduced. The pixel array includes m 占 n (n = 1 to n) pixels formed in a pixel region defined by m (m is a positive integer) data lines S1 to Sm and n (n is a positive integer) gate lines And includes pixels 11. Each of the pixels 11 is connected to TFTs (Thin Film Transistors) formed at intersections of the data lines S1 to Sm and the gate lines G1 to Gn, a pixel electrode for charging a data voltage, A storage capacitor (Cst) for holding a data voltage, and the like. The structure of the pixels 11 may be changed according to the driving characteristics of the flat panel display.

The pixel array of the display panel 100 further includes touch sensors Cs and sensor wirings L1 through Li connected to the touch sensor electrodes C1 through C4 where i is a positive integer smaller than m and n do. The touch sensor electrodes C1 to C4 may be implemented by a method of dividing a common electrode connected to a plurality of pixels. One touch sensor electrode (C1 to C4) is commonly connected to the plurality of pixels (11) and forms one touch sensor (Cs). Accordingly, the touch sensors supply the common voltage Vcom of the same potential to the pixels 11 during the display period, and are driven by the touch sensing unit 110 during the touch sensing period to sense the touch input.

The touch sensors built in the pixel array can be implemented with capacitive type touch sensors. The capacitance type can be divided into self capacitance and mutual capacitance. The self-capacitance is formed along a conductor wiring of a single layer formed in one direction. The mutual capacitance is formed between two orthogonal conductor wirings. FIG. 9 shows a self-capacitance type touch sensor, but the touch sensors are not limited thereto.

A black matrix, a color filter, or the like may be formed on the upper substrate of the display panel 100.

The display driver circuit includes a data driver 102, a gate driver 104 and a timing controller 106 and writes the data of the input image to the pixels 11 of the display panel 100 during the time-divided display period. The data driver 102 converts digital video data of an input image input from the timing controller 106 during a display period into a gamma compensation voltage and outputs a data voltage through output channels. The data voltage output from the data driver 102 is supplied to the data lines S1 to Sm during the display period. The output channels of the data driver 102 may be separated from the data lines S1 to Sm during the touch sensing period to maintain a high impedance state. The voltage of the pixels 11 is maintained as the data voltage by the storage capacitor since the TFTs are not turned on during the touch sensing period.

A multiplexer (not shown) may be disposed between the data driver 102 and the data lines S1 to Sm. This multiplexer may be formed on the substrate of the display panel 100 or may be integrated in the drive IC together with the data driver 102. The multiplexer distributes the data voltage input from the data driver 102 to the data lines S1 to Sm under the control of the timing controller 106. [ In the case of the 1: 2 multiplexer, the multiplexer time-divides the data voltages input through one output channel of the data driver 102 and supplies the data voltages to the two data lines S1 and S2 in a time-division manner. Therefore, when the 1: 2 multiplexer is used, the number of channels of the drive IC can be reduced to 1/2. The data driver 102 may be directly bonded onto the substrate of the display panel 100 by a COG (Chip on Glass) process.

The gate driver 104 includes a shift register that sequentially outputs gate pulses to the gate lines G1 to Gn of the display panel 100 in response. The gate driver 104 sequentially supplies gate pulses (or scan pulses) synchronized with the data voltages to the gate lines G1 to Gm using the shift register during the display period to sequentially apply the data voltages to the display panel 100, ≪ / RTI > During the touch sensing period, the shift clock is not input to the gate driver 104. [ As a result, the gate driver 104 does not output the gate pulse during the touch sensing period. The gate driver 104 may be implemented as a GIP (Gate In Panel) circuit formed together with the pixel array on the lower substrate of the display panel 100, and may be glued to a separate IC.

The timing controller 106 transmits the digital video data of the input image received from the host system (not shown) to the data driver 12. The timing controller 106 outputs 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 received in synchronization with the input video data And outputs a data timing control signal for controlling the operation timing of the data driver 102 and a gate timing control signal for controlling the operation timing of the gate driver 104. The gate 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. Since the polarity of the data voltage is not inverted, the polarity control signal (POL) for inverting the polarity of the data voltage is not required in an organic light emitting diode (OLED) display.

The host system may be implemented in any one of a television system, a set-top box, a navigation system, a DVD player, a Blu-ray player, a personal computer (PC), a home theater system, and a phone system. The host system includes a system on chip (SoC) with a built-in scaler to convert the digital video data of the input image into a format suitable for display on the display panel 100. The host system transmits timing signals (Vsync, Hsync, DE, MCLK) to the timing controller 106 together with the digital video data of the input video. In addition, the host system executes an application program associated with the coordinate information of the touch input received from the touch sensing unit 110. [

The touch sensing unit 110 drives the touch sensors during the touch sensing period in response to the synchronization signal Tsync input from the timing controller 106 or the host system. The touch sensing unit 110 supplies a touch driving signal to the sensor wirings L1 to Li during the touch sensing period to sense the touch input. The touch sensing unit 110 determines the touch input by analyzing the charge variation of the touch sensor depending on the presence or absence of the touch input, and calculates coordinates of the touch input position. The coordinate information of the touch input position is transmitted to the host system. The touch sensing unit 110 may be implemented as a plurality of ROICs 61 and 62 and may be connected to the MCU 50 through an SPI interface in the same manner as shown in FIG.

At least a part of the touch sensing unit 110 may be integrated with the data driver 102 in one IC. Hereinafter, an IC including the touch sensing unit 110 and the data driver 102 is referred to as an SRIC.

9 shows SRICs in which the touch sensing unit 100 and the data driver 102 are incorporated. In FIG. 9, the MCU is mounted on a printed circuit board (PCB) 200 electrically connected to the display panel 100. The SRICs are directly bonded to the substrate of the display panel 100 by a COG process. MCUs and SRICs are connected via SPI without a GPIO channel as shown in FIG. 3 and FIG.

10 is a view showing a plane arrangement of the in-cell type touch sensors and a circuit configuration of the touch sensing unit.

Referring to FIG. 10, each of the touch sensor electrodes COM1 through COM4 may be formed as a divided pattern of a common electrode connected to a plurality of pixels.

The touch sensing unit 110 includes a multiplexer 111 and a sensing circuit 112.

The multiplexer 111 sequentially selects sensor wirings L1 to L3 connected to the sensing circuit 112 under the control of the MCU 113 in a predetermined order. The multiplexer 111 can supply the common voltage Vcom under the control of the MCU 113. [ Each of the multiplexers 111 reduces the number of channels of the sensing circuit 112 by sequentially arranging N sensor wirings L1 to L3 on the channels of the sensing circuit 112. [

The sensing circuit 112 amplifies and integrates the charge amount of the sensor wiring signal received through the multiplexer 111 and converts it into digital data. The sensing circuit 112 includes an amplifier for amplifying the received touch sensor signal, an integrator for accumulating the output voltage of the amplifier, an analog-to-digital converter (ADC) for converting the voltage of the integrator into digital data, Quot;). The digital data output from the ADC is transmitted to the MCU 113 as touch data. Each of the touch sensing units 111 is integrated into an IC (ROIC or SRIC).

The MCU 113 is connected to the ICs including the touch sensing unit 110 through the SPI as shown in FIGS. The MCU 113 controls the multiplexer 111 to connect the sensor wirings 115 to the sensing circuit 112. The MCU 113 compares the touch data received from the sensing circuit 112 with a predetermined threshold value to determine a touch input. The MCU 113 executes a preset touch sensing algorithm to calculate coordinates for each touch input position to generate touch coordinate data XY and to generate touch coordinate data XY, And transmits a touch report to the host system 108.

11 is a waveform diagram showing a driving signal of a display device according to an embodiment of the present invention. In Fig. 11, Gate is the voltage of the gate lines G1 to Gn, and Data is the voltage of the data lines S1 to Sm. Vcom is the voltage of the touch sensor electrode.

Referring to FIG. 11, one frame period may be time-divided into a plurality of display periods Td1 and Td2 and a plurality of touch sensing periods Tt1 and Tt2. The display drive circuits 102, 104 and 106 write the current frame data to the pixels of the first block B1 during the first display period Td1 to output the image reproduced in the first block B1 as the current frame data Update.

During the first display period Td1, the block B2 excluding the first block B1 retains the previous frame data, and the touch sensor driver 110 does not drive the touch sensors. Then, the touch sensor driver 110 drives all the touch sensors sequentially during the first touch sensing period Tt1 to sense the touch input, and generates a touch report including coordinate information and identification information (ID) for each touch input To the host system. The touch sensing unit 110 supplies a touch sensor driving signal to the touch sensor through the sensor wirings L1 to Li during the touch sensing period Tt1 to detect the amount of charge of the touch sensor before and after the touch input, And judges the touch input by comparison.

Subsequently, the display driving circuits 102, 104, and 106 write the current frame data to the pixels of the second block B2 during the second display period Td2 to output the image reproduced in the second block B2 to the current frame Update with data. During the second display period Td2, the first block B1 maintains the previous frame data, and the touch sensor driver 110 does not drive the touch sensors. Then, the touch sensor driver 110 sequentially drives all the touch sensors during the second touch sensing period Tt2 to sense the touch input, and generates a touch report including coordinate information and identification information (ID) for each touch input To the host system.

The touch sensing unit 110 supplies a touch sensor driving signal to the touch sensor through the sensor wirings L1 to Li during the touch sensing periods Tt1 and Tt2 to detect the amount of charge of the touch sensor before and after the touch input, The touch input is compared with the voltage.

The touch sensing unit 110 may transmit the touch report to the host system at a touch report rate higher than the frame rate. For example, when the frame rate is 60 Hz, the touch report rate may be 120 Hz or more. The frame rate is the frame frequency at which one frame image is written to the pixel array. The touch report rate is the rate at which the coordinate information of the touch input is generated. The higher the touch report rate is, the faster the coordinate recognition speed of the touch input becomes, thereby improving the touch sensitivity.

The data driver 102 may supply the AC signal LFD having the same phase as the touch sensor driving signal during the touch sensing periods Tt1 and Tt2 in order to reduce the parasitic capacitance between the pixels 11 and the touch sensors have. Similarly, in order to reduce the parasitic capacitance between the pixels 11 and the touch sensors, the gate driver 102 applies an AC signal LFD having the same phase as the touch sensor driving signal during the touch sensing periods Tt1 and Tt2 Can supply. The touch sensing unit 110 supplies the AC signal LFD to the sensor wirings other than the sensor wirings connected to the touch sensors that currently sense the touch input, thereby preventing the parasitic capacitance between the neighboring touch sensors.

In Insel touch sensor technology, a common electrode connected to pixels of the display panel 100 is divided into touch sensor units and utilized as electrodes of the touch sensors Cs. For example, as described above, in the case of a liquid crystal display device, the in-line touch sensor technology divides the common electrode 12 and divides the divided common electrode patterns into capacitance type touch sensors Cs ). Since these touch sensors are coupled with the pixels, the parasitic capacitance between the touch sensors and the pixels becomes large. Since the touch sensors and the pixels are coupled through the parasitic capacitance, the pixels and the touch sensors are time-division driven as shown in FIG. 4 because they may adversely affect each other electrically. Even in the time division driving method, the touch sensitivity of the touch sensors and the touch recognition accuracy may be deteriorated due to the parasitic capacitance of the display panel 100.

The data lines S1 to Sm and the gate lines G1 to Gm of the display panel 100 during the touch sensing periods Tt1 and Tt2 and the alternating current When the signal LFD is supplied, the amount of charge of the parasitic capacitance of the display panel 100 can be reduced. This is because the voltage difference across the parasitic capacitance can be minimized to minimize the amount of parasitic capacitance charged. Reducing the parasitic capacitance of the touch sensor improves the signal to noise ratio (SNR) of the touch sensor signal, thereby widening the operation margin of the touch sensing part and improving the touch input and the touch sensitivity .

12 to 14 are diagrams showing examples of a touch data transmission method using SPI in various insole touch sensing methods. 12 and 13 are views showing an example of a touch sensing method using LHB (Long Horizontal Blank).

Referring to FIGS. 12 and 13, an in-cell touch sensing method divides one frame period into a plurality of display periods and a plurality of touch sensing periods. Each of the touch sensing periods may be longer than one horizontal period and shorter than a half frame period. In Fig. 12, " Tsync " is a synchronous signal defining a display period (high level) and a touch sensing period (low level) as different logical values. Each of the ICs (ROIC or SRIC) in which the touch sensing unit 110 is integrated senses the touch input in response to the synchronization signal Tsync and is synchronized with the display driving circuits 102, 104, and 106. 12 and 14, the GSP is a gate start pulse. The gate start pulse (GSP) may be generated once at the start timing of one frame period within one frame period.

In FIGS. 12 and 13, the 84.times.48 touch sensors are divided into eight touch sensor groups and driven in a divided manner. The first touch sensor group including 14 x 6 touch sensors Cs per IC is driven in the first touch sensing period (1st Tsync Low interval). The eighth touch sensor group including 14 x 6 touch sensors Cs per IC is driven in the eighth touch sensing period (8th Tsync Low section). During the first to eighth touch sensing periods, the touch input is sensed to the touch sensors of the entire touch screen to obtain the first touch report. The first touch sensor group is driven again in the ninth touch sensing period (9th Tsync Low interval). And the eighth touch sensor group is driven in the 16th touch sensing period (16th Tsync Low interval). During the ninth through sixteenth touch sensing periods, the touch input is sensed with respect to all the touch sensors of the touch screen to obtain a second touch report.

The touch screen may be implemented as 84 x 48 touch sensors built in the pixel array of the display panel 100 as shown in Fig. Numeral 84 denotes the number of touch sensors disposed along the column direction and numeral 48 denotes the number of touch sensors disposed along the row direction. In order to drive the touch sensors Cs of the touch screen, two touch sensing units RO and R1 may be incorporated per IC. When two touch sensing units RO and R1 are embedded in one IC (ROIC or SRIC), six ICs are required to drive the touch sensors as shown in FIG. Each of the touch sensing units R0 and R1 receives and simultaneously amplifies and integrates the signals of 14 x 3 touch sensors during one touch sensing period and sequentially inputs the signals to the ADC to output touch data, Receives signals of three touch sensors at the same time, amplifies and integrates them, sequentially inputs the signals to the ADC, and outputs touch data. 14 x 3, "14" is the number of touch sensors arranged along the column direction, and "3" is the number of touch sensors arranged along the row direction.

FIG. 14 is a diagram illustrating an example of a touch sensing method using VB (Vertical Horizontal Blank).

Referring to FIG. 14, one frame period is divided into a display period (Td) and a touch sensing period (Tt). The touch sensing period Tt is assigned to a vertical blank period. The timing controller 106 can expand the vertical blank period by compressing the display period Td within one frame period to sufficiently ensure the touch sensing period Tt.

The two touch sensing units R0 and R1 in the ICs (ROIC or SRIC) simultaneously connect the sensor wirings L1 to Li to the sensing circuit 112 during the touch sensing period Tt. The ICs (ROIC or SRIC) time-divisionally drive the touch sensors of the entire touch screen during the touch sensing period (Tt) to output touch data. The MCU analyzes the touch data received from the ICs (ROIC or SRIC) received via the SPI and generates a touch report once for each frame period.

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.

11: pixel electrode 12: touch sensor electrode
100: display panel 102: data driver
104: scan driver 106: timing controller
110: Touch sensing unit

Claims (5)

A display panel having a plurality of touch sensors connected to the data lines and the gate lines and connected to the pixels;
A display driving circuit for writing data of an input image to the pixels in a plurality of display periods divided within one frame period;
A plurality of integrated circuits (ICs) for amplifying and integrating the signals of the touch sensors in a touch sensing period allocated during the display periods within the one frame period and converting the signals into digital data to output data by touching; And
And a microcontroller (MCU) connected to the integrated circuits through an SPI (Serial Peripheral Interface), analyzing data by touching from the integrated circuits, and outputting coordinates information of each of the touch inputs,
When the micro control unit toggles a signal of a MISO channel among the SPI channels in an SPI standby state, it transmits commands and dummy data through a MOS (Master Output Slave Input) channel in synchronization with a clock, And a touch screen for receiving data from the integrated circuits through the channel via the touch. The method according to claim 1,
Wherein the integrated circuits are configured to toggle a signal of the MISO channel when the preparation for transferring data by the touch is completed and to output the data through the MISO channel with the touch by the amount of data received when the dummy data is received . The method according to claim 1,
The micro-
A start signal generator for generating a start signal when the signal of the MISO channel is 1 (= high level) in a standby state in which a signal of a CS (Slave Select or Chip Enable) channel is 1 (= high level);
And an SPI control unit for activating a communication channel of the SPI in response to the start signal to start SPI communication. The method according to claim 1,
Wherein the microcontroller unit and the integrated circuits have a touch screen connected via the CS channel, the MISO channel, the MOSI channel, and a SCLK (Serial Clock) channel through which the clock is transmitted without a general purpose input-output (GPIO) Display device. A plurality of slave elements for amplifying and integrating the signals of the touch sensors and converting the signals into digital data to output data by touch; And
And a master device connected to the slave devices through SPI (Serial Peripheral Interface) to analyze coordinate data received from the slave devices and output coordinate information of each of the touch inputs,
When the master device toggles a signal of a master input slave output (MISO) channel among the SPI channels in an SPI standby state, it transmits commands and dummy data through a master output slave input (MOSI) And a touch screen for receiving data from the slave devices through the touch via the touch panel.

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