KR101992853B1 - Touch sensing system - Google Patents

Abstract

The present invention relates to a touch sensing system, comprising: a ROIC for driving a touch sensor to sense a change in voltage of the touch sensors to sense a touch input; And an MCU analyzing the touch raw data received from the ROIC and calculating coordinates of each of the touch inputs. The ROIC may include a sensing unit which senses a voltage change of the touch sensor and outputs touch raw data; A buffer memory in which the touch raw data is stored; A data transmitter for transmitting the touch raw data to the MCU; And a memory controller storing the touch raw data input from the sensing unit in the buffer memory and simultaneously reading previous touch raw data from the buffer memory and supplying the touch raw data to the data transmitter.

Description

Touch Sensing System {TOUCH SENSING SYSTEM}

The present invention relates to a touch sensing system.

A user interface (UI) allows a person (user) to easily control various electronic devices as desired. Representative examples of the user interface include a keypad, a keyboard, a mouse, an on screen display (OSD), a remote controller having an infrared communication or a high frequency (RF) communication function. User interface technology continues to evolve in the direction of increasing user sensitivity and ease of operation. In recent years, user interfaces have evolved into touch UIs, voice recognition UIs, 3D UIs, and the like.

Touch UI is essential for portable information devices. The touch UI is implemented by a method of forming a touch screen on a screen of a display device.

The mutual capacitive touch screen includes Tx lines, Rx lines orthogonal to the Tx lines, and touch sensors formed between the Tx lines and the Rx lines. The sensing circuit supplies a drive signal to the Tx line and at the same time senses the change in voltage of the touch sensor via the Rx line. The sensing circuit detects a change in the touch sensor voltage before and after the touch and determines whether and where the conductive material touches the touch screen. This sensing circuit is integrated in an integrated circuit called a readout integrated circuit (ROIC) and connected to a touch screen.

In general, one ROIC is connected to one touch screen. As the size and resolution of the touch screen increases, the number of Tx channels and Rx channels of the touch screen also increases. Therefore, according to the prior art, when the size and resolution of the touch screen increases, the ROIC needs to be newly developed for the touch screen.

In order to increase a user's touch sensitivity in a touch sensing system, a touch report rate should be increased. The touch report rate refers to a speed or frequency (Hz) of transmitting coordinate information of touch data obtained by sensing touch sensors in a touch screen to an external host system. Increasing the touch report rate reduces the time delay between the touch input and the response speed of the system, increasing the user's sensitivity.

In general, the touch sensing system transmits coordinate data of a touch input position obtained through a sensing period, a touch raw data transmission period, and a coordinate calculation period as shown in FIG. 1. During the sensing period, a driving signal is applied to the touch sensors of the touch screen TSP and the voltage of the touch sensor is sensed in synchronization with the driving signal. During the sensing period, the voltage of the touch sensor is converted into digital data through an analog to digital converter (hereinafter, referred to as "ADC"). When touch raw data (TData) is obtained through this process, the touch raw data is transmitted to the microcontroller unit (MCU) during the touch raw data transmission period. The MCU executes a preset touch recognition algorithm during the coordinate calculation period, analyzes the received touch raw data to detect the touch input position, calculates the coordinates of the touch input position, and transmits the coordinate data to the host system. . In this way, the coordinate data of the touch input position is transmitted to the host system once during one touch screen frame period (hereinafter, referred to as a "frame period") that combines a sensing period, a touch raw data transmission period, and a coordinate calculation period. Therefore, the touch report rate is equal to one frame rate of the touch screen TSP. In FIG. 1, FN is an Nth frame period and F (N + 1) is an N + 1th frame period.

The present invention provides a touch sensing system that can increase the touch report rate.

The touch sensing system of the present invention includes a ROIC for driving a touch sensor to sense a change in touch voltage to sense a touch input; And an MCU analyzing the touch raw data received from the ROIC and calculating coordinates of each of the touch inputs.
The ROIC may include a sensing unit which senses a voltage change of the touch sensor and outputs touch raw data; A buffer memory in which the touch raw data is stored; A data transmitter for transmitting the touch raw data to the MCU; And a memory controller for storing the touch raw data input from the sensing unit in the buffer memory and simultaneously reading previous touch raw data from the buffer memory and supplying the touch raw data to the data transmitter.

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The touch sensing system of the present invention may include: first and second ROICs configured to sense the touch input by sensing the voltage change of the touch sensors by dividing the touch sensors; And an MCU that analyzes touch raw data received from the first and second ROICs and calculates coordinates of each of the touch input positions.
Each of the first and second ROICs includes the sensing unit, the buffer memory, the data transmitter, and the memory controller.
The ROICs receive a voltage of the touch sensors by alternately supplying a driving signal to the touch sensors in charge while transmitting and receiving a synchronization signal through one pin.

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The present invention can increase the touch report rate by processing touch screen sensing and coordinate calculation in parallel. Furthermore, the present invention divides and drives a large touch screen by synchronizing a plurality of ROICs. As a result, the present invention can improve the touch report rate by parallel processing of touch screen sensing and coordinate calculation when driving a large touch screen with a multi-chip composed of multiple ROICs.

1 is a diagram illustrating an operation of a touch sensing system.
2 is a block diagram illustrating a touch sensing system according to an embodiment of the present invention.
3 is an enlarged plan view of a portion of the touch screen illustrated in FIG. 1.
4 to 6 illustrate various combinations of a touch screen and a display panel.
FIG. 7 illustrates an example of parallel processing of sensing a touch screen, transmitting touch raw data, receiving touch raw data, and executing a touch recognition algorithm in the touch sensing system according to an exemplary embodiment of the present invention.
FIG. 8 is a diagram illustrating a split driving method of a touch screen using a multi-chip in a touch sensing system according to an exemplary embodiment of the present invention.
9 and 10 are diagrams illustrating an operation sequence of the ROICs illustrated in FIG. 8.
FIG. 11 is a diagram illustrating an example of applying one of the ROICs illustrated in FIG. 8 to a small touch screen.
12 is a block diagram showing ROICs in detail.

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 display device will be described mainly as a liquid crystal display device as an example of a flat panel display device, but the display device of the present invention is not limited to the liquid crystal display device.

The touch sensing system of the present invention may be implemented as a capacitive touch screen that senses a touch input through a plurality of capacitive sensors. The capacitive touch screen includes a plurality of touch sensors. Each of the touch sensors includes a capacitance when viewed in equivalent circuitry. The capacitance can be divided into self capacitance or mutual capacitance. The self capacitance is formed along a single layer of conductor wiring formed in one direction. Mutual capacitance is formed between two orthogonal conductor wires. In the following embodiments, although a mutual capacitive touch screen is illustrated, it should be noted that the touch sensing system of the present invention is not limited to the mutual capacitive touch screen.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like numbers refer to like elements throughout. 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.

2 to 6, the touch sensing system of the present invention includes a touch screen (TSP), a ROIC 30, an MCU 40, and the like. The touch screen TSP is bonded on the upper polarizing plate POL1 of the display panel DIS as shown in FIG. 4, or is formed between the upper polarizing plate POL1 and the upper substrate GLS1 of the display panel DIS as shown in FIG. 5. Can be. In addition, the touch sensors Cts of the touch screen TSP may be embedded in the lower substrate in an in-cell type together with the pixel array in the display panel DIS as shown in FIG. 6. 4 to 6, "PIX" means a pixel electrode of a liquid crystal cell, "GLS2" means a lower substrate, and "POL2" means a lower polarizing plate, respectively.

In the display panel DIS, a liquid crystal layer is formed between two substrates. The pixel array of the display panel DIS includes pixels formed in the pixel area defined by the data lines D1 to Dm, where m is a positive integer, and the gate lines G1 to Gn, where n is a positive integer. . Each of the pixels is connected to TFTs formed at intersections of the data lines D1 to Dm and the gate lines G1 to Gn, a pixel electrode to charge a data voltage, and a pixel electrode. Storage capacitors (Cst) for maintaining the voltage and the like.

Black matrices, color filters, and the like are formed on the upper substrate of the display panel DIS. The lower substrate of the display panel DIS may be implemented as a color filter on TFT (COT) structure. In this case, the black matrix and the color filter may be formed on the lower substrate of the display panel DIS. The common electrode supplied with the common voltage may be formed on the upper substrate or the lower substrate of the display panel DIS. A polarizing plate is attached to each of the upper and lower substrates 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 is formed between the upper substrate and the lower substrate of the display panel DIS to maintain a cell gap of the liquid crystal cell.

The liquid crystal mode of the display panel DIS may be implemented in any known liquid crystal mode, such as twisted nematic (TN) mode, vertical alignment (VA) mode, in plane switching (IPS) mode, or fringe field switching (FFS) mode. . The backlight unit may be disposed under the rear surface 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, and the timing controller 20 to write 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 output from the data driver circuit 12 is supplied to the data lines D1 to Dm. The scan driving circuit 14 sequentially supplies gate pulses (or scan pulses) synchronized with the data voltages to the gate lines G1 to Gn to select a line of the display panel DIS to which the data voltages are written.

The timing controller 20 inputs timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal Data Enable, DE, and a main clock MCLK input from the host system 50. In response, the operation timings of the data driver circuit 12 and the scan driver circuit 14 are synchronized. 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, POL), a source output enable signal (Source Output Enable, SOE), and the like.

The host system 50 may be implemented as 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 50 includes a system on chip (SoC) having a built-in scaler to convert digital video data RGB of an input image into a format suitable for displaying on the display panel DIS. The host system 50 transmits timing signals Vsync, Hsync, DE, and MCLK together with the digital video data to the timing controller 20. In addition, the host system 50 executes an application program associated with the coordinate information XY of the touch data input from the MCU 40.

The touch screen TSP includes Tx lines (Tx1 to TxN, N is a positive integer less than n), and Rx lines (Rx1 to RxM, M is a small amount of m), which intersects the Tx lines (Tx1 to TxN). Integer), and M × N touch sensors Cts formed at intersections of the Tx lines Tx1 to TxN and the Rx lines Rx1 to RxM. Each of the touch sensors Cts includes mutual capacitance.

The ROIC 30 includes a driver 32, a sensing unit 34, and a touch timing generator 36. The ROIC 30 applies a driving signal to the touch sensors Cts through the Tx lines Tx1 to TxN and receives voltages of the touch sensors through the Rx lines Rx1 to RxM in synchronization with the driving signal. do. The ROIC 30 converts the received touch sensor voltage into touch raw data, which is digital data, using an ADC, and transmits the converted touch sensor voltage to the MCU 40. The driving signal may be generated in various forms such as a pulse, a sinusoidal wave, and a triangular wave. When the size of the touch screen TSP is increased, the touch screen TSP cannot be driven by one ROIC 30. When the size of the touch screen TSP is increased, the touch sensing system of the present invention drives the touch screen TSP with two or more ROICs 30A and 30B which are synchronized while transmitting and receiving a synchronization signal as shown in FIGS. 8 to 10.

The ROIC 30 stores the touch raw data TData obtained by sensing the touch screen TSP using the DMA in the buffer memory, and reads the previous touch raw data from the buffer memory and transmits it to the MCU 40. Accordingly, the ROIC 30 processes touch screen sensing and coordinate calculation in parallel as shown in FIG. 7. As a result, the ROIC 30 performs touch screen sensing and coordinate calculation at the same time, thereby greatly improving the touch report rate by significantly reducing one frame period required from sensing of the touch screen to coordinate calculation. While touch screen sensing and coordinate calculation are parallelized, the transmission and reception of touch raw data is also parallelized.

The driver 32 selects a Tx channel to output a drive signal under the control of the touch timing generator 36, and applies a drive signal to Tx lines Tx1 to TxN connected to the selected Tx channel. The Tx lines Tx1 to TxN are charged during the high potential period of the driving signal to supply electric charges to the touch sensors Cts and are discharged in the low potential period of the driving signal. The driving signal is applied to each of the Tx lines Tx1 to TxN through the Rx lines Rx1 to RxM so that the voltages of the touch sensors Cts are accumulated in the capacitor of the integrator built in the sensing unit 34. Can be supplied continuously.

The sensing unit 34 sets the Rx channel under the control of the touch timing generator 36, and adjusts the voltage of the touch sensor through the Rx lines Rx (i) and Rx (i + 1) connected to the Rx channel. Receive. The sensing unit 34 converts the received voltage of the touch sensor into digital data through the ADC and outputs touch raw data.

The touch timing generator 36 controls the Tx channel and the Rx channel settings and synchronizes the driver 32 and the sensing unit 34.

The MCU 40 executes a preset touch recognition algorithm. Any known algorithm may be used as the touch recognition algorithm. The touch recognition algorithm compares the touch raw data input from the sensing unit 34 with a predetermined threshold, and determines the touch raw data having the threshold value or more as touch input data obtained from the touch sensors at the touch input position. The touch recognition algorithm assigns an identification code to each of the touch input data above the threshold and calculates coordinates of each of the touch input positions. The MCU 40 transmits an identification code and coordinate information XY of each of the touch input data to the host system 50.

FIG. 7 illustrates an example of parallel processing of sensing a touch screen, transmitting touch raw data, receiving touch raw data, and executing a touch recognition algorithm in the touch sensing system according to an exemplary embodiment of the present invention.

Referring to FIG. 7, the touch sensing system of the present invention performs parallel processing of sensing a touch screen, transmitting touch raw data, receiving touch raw data, and executing a touch recognition algorithm. The touch sensing system of the present invention can improve the touch report rate by performing such parallel processing.

During the Nth frame period FN, the ROIC 30 applies a driving signal to the Tx lines Tx1 to TxN of the touch screen TSP to receive a touch sensor voltage and sense the touch screen TSP. Then, the touch raw data (TData) obtained as a result of sensing in the N-1th frame period F (N-1) is transmitted to the MCU 40. The MCU 40 analyzes the touch raw data TData of the N-1th frame period F (N-1) received from the ROIC 30 during the Nth frame period FN by a touch recognition algorithm, and then touches it. Determine input data and calculate coordinates of each of the touch input data.

Subsequently, during the N + 1th frame period F (N + 1), the ROIC 30 receives a touch sensor voltage by applying a driving signal to the Tx lines Tx1 to TxN of the touch screen TSP and touches the touch signal. At the same time as sensing the screen TSP, the touch raw data TData obtained as a result of sensing in the Nth frame period FN is transmitted to the MCU 40. The MCU 40 analyzes the touch raw data TData of the Nth frame period FN received from the ROIC 30 during the N + 1th frame period F (N + 1) by using a touch recognition algorithm, and then touches it. Determine input data and calculate coordinates of each of the touch input data.

Such parallel processing may be implemented using direct memory access (“DMA”) of the ROIC 30. The DMA of the ROIC 30 stores the touch raw data in the buffer memory and simultaneously reads the previous touch raw data from the buffer memory and transmits it to the MCU 40 to enable parallel processing as shown in FIG. 7. To this end, the ROIC 30 further includes a DMA controller, a buffer memory, and the like.

FIG. 8 is a diagram illustrating a split driving method of a touch screen using a multi-chip in a touch sensing system according to an exemplary embodiment of the present invention.

Referring to FIG. 8, the touch sensing system of the present invention includes two or more ROICs 30A and 30B for driving the touch screen TSP. 8 to 10, "IC # 1" refers to the first ROIC 30A, and "IC # 2" refers to the second ROIC 30B. In the following embodiment, the sensing circuit is illustrated as two ROICs 30A and 30B. However, when the size of the touch screen TSP is larger, the number of ROICs may be increased.

The ROICs 30A and 30B alternately supply driving signals to Tx lines of the touch screen (TSP) in charge of oneself while transmitting and receiving synchronization signals through one pin, and synchronize the driving signals with the driving signals. The touch sensor voltage is received through the Rx lines of the touch screen TSP. The ROICs 30A and 30B may drive the touch screen TSP in four divisions as shown in FIG. 8. In this case, the first ROIC 30A supplies driving signals to the Tx lines Tx1 to Tx15 formed in the upper half blocks A and C of the touch screen TSP and the left half of the touch screen TSP. The voltages of the touch sensors Cts are received through the Rx lines Rx1 to Rx27 formed in the blocks A and B. The second ROIC 30B supplies driving signals to the Tx lines Tx16 to Tx31 formed in the lower half blocks B and D of the touch screen TSP, and the right half blocks C of the touch screen TSP. The voltages of the touch sensors Cts are received through the Rx lines Rx28 to Rx54 formed at D).

In FIG. 8, "SENSE_READY_OUT" is one of the output pins of the ROIC, and a signal indicating that the setting required for the sensing operation is completed is output to the ROICs 30A and 30B. "SENSE_READY_IN" is an input pin of the ROICs 30A and 30B through which the SENSE_READY_OUT signal is received. The ROICs 30A and 30B receiving the SENSE_READY_OUT signal generate a synchronization signal SYNC to synchronize the sensing operation timing with another ROIC. SPI_1 is a Serial Peripheral Interface (SPI) interface in which touch raw data is transmitted between the first ROIC 30A and the MCU 40. SPI_2 is an SPI interface through which touch raw data is transmitted between the second ROIC 30B and the MCU 40. The SPI interface can be replaced with another serial interface, such as an I ² C interface or a universal serial bus (USB). RDR_1 is a signal that informs the MCU 40 of the start timing of the transmission of the touch raw data of the first ROIC 30A. RDR_2 is a signal that informs the MCU 40 of the start timing of the transmission of the touch raw data of the second ROIC 30B. The ROICs 30A and 30B simultaneously transmit the sorted touch raw data following the RDR_1 and RDR_2 to the MCU 40. NMI_1 and NM2 are the next sensing start timing signals fed back from the MCU 40 to the ROICs 30A and 30B. When the MCU 40 receives the touch raw data of the first ROIC 30A, the MCU 40 transmits NMI_1 to the first ROIC 30A to control the next sensing start timing of the first ROIC 30A. When the MCU 40 receives the touch raw data of the second ROIC 30B, the MCU 40 transmits NMI_2 to the second ROIC 30B to control the next start timing of the second ROIC 30B.

9 and 10 are diagrams showing an operation sequence of the ROICs 30A and 30B shown in FIG. 8.

9 and 10, the ROICs 30A and 30B alternately supply a driving signal to the Tx channels in charge of the driving signal by exchanging and receiving a synchronization signal SYNC through one pin, and then supplying the driving signal to the driving signal. In synchronization, it receives the touch sensor voltage through its own Rx channels.

During the first sensing time Ts1, the first ROIC 30A operates as a master device to transmit the synchronization signal SYNC to the second ROIC 30B and outputs a driving signal to synchronize with the second ROIC 30B. Sensing the touch sensor voltage. The second ROIC 30B operates as a slave device that receives the touch sensor voltage in response to the synchronization signal SYNC received from the first ROIC 30A during the first sensing period Ts1. At the beginning of the first sensing time Ts1, the first and second ROICs 30A and 30B set the synchronization signal mode in a software setting method. The touch timing generation unit 36a of the first ROIC 30A changes the synchronization signal setting to the output attribute # 1 SYNC MODE OUT, and is set to the transmission standby state of the synchronization signal SYNC. At the same time, the touch timing generation unit 36b of the second ROIC 30B changes the synchronization signal setting to the input attribute # 2 SYNC MODE IN and is set to the reception wait state of the synchronization signal SYNC.

Subsequently, the first ROIC 30A sets Tx channels and Rx channels based on Tx and Rx setup information stored in a register (not illustrated) (# 1 Touch Start Setting). At the same time, the second ROIC 30B sets the Rx channels based on the Rx setup information stored in the register (# 2 Touch Start Setting). When the first ROIC 30A receives the # 2 SENSE READY OUT SET from the second ROIC 30B after the # 1 Touch Start Setting, the first ROIC 30A starts to generate the synchronization signal SYNC (# 1 SYNC OUT) to start the sensing operation. (# 1 Sensing start), the second ROIC (30B) may start the sensing operation (# 1 Sensing start) when the synchronization signal (SYNC) is received.

The second ROIC 30B transmits a signal indicating that the sensing preparation is completed immediately after the # 2 Touch Start Setting process to the first ROIC 30A (# 2 SENSE READY OUT SET). When the first ROIC 30A receives the # 2 SENSE READY OUT SET signal, the first ROIC 30A transmits the sync signal SYNC to the second ROIC 30B (# 1 SYNC OUT), and transmits the sync signal SYNC to the touch timing generator. Feedback is input to 36a to synchronize the sensing operation of the internal circuit and the second ROIC 30B. The first ROIC 30A supplies the driving signal to all Tx lines Tx1 to Tx15 in charge of the driving signal immediately after outputting the synchronization signal SYNC, and in synchronization with the driving signal, # 1 Sensing Start. In the process, the voltages of the touch sensors existing in the left half of the touch screen TSP are received through the Rx lines Rx1 to Rx27 and converted into touch raw data. Tx lines Tx1 to Tx15 are formed at upper half portions A and C of the touch screen TSP. Rx lines Rx1 to Rx27 are formed at the left halves A and B of the touch screen TSP. Since the second ROIC 30B does not output the driving signal while the driving signal is output from the first ROIC 30A, power consumption can be reduced. The second ROIC 30B is located in the right half of the touch screen TSP through the Rx lines Rx28 to Rx54 during the # 2 Sensing Start process in synchronization with the driving signal output from the first ROIC 30A. After receiving the voltages of the two signals and converting them into touch raw data, all the touch screen partitions in charge of their own are sensed and transmitted to the first ROIC (30A) that the sensing is completed and reset (# 2 SENSE READY OUT RESET) . Rx lines Rx28 to Rx54 are formed on the right half portions C and D of the touch screen TSP.

During the second sensing time Ts2, the second ROIC 30B operates as a master device to transmit the synchronization signal SYNC to the first ROIC 30A, and outputs a driving signal to synchronize with the first ROIC 30A. Sensing the touch sensor voltage. The first ROIC 30A operates as a slave device that receives the touch sensor voltage in response to the synchronization signal SYNC received from the second ROIC 30B during the second sensing period Ts2. At the beginning of the second sensing time Ts2, the first and second ROICs 30A and 30B set the synchronization signal mode in a software setting method. The touch timing generation unit 36b of the second ROIC 30B changes the synchronization signal setting to the output attribute # 2 SYNC MODE OUT, and is set to the transmission standby state of the synchronization signal SYNC. At the same time, the touch timing generation unit 36a of the first ROIC 30A changes the synchronization signal setting to the input attribute # 1 SYNC MODE IN and is set to a reception wait state of the synchronization signal SYNC.

Subsequently, the second ROIC 30B sets Tx channels and Rx channels based on the Tx and Rx setup information stored in the register (# 2 Touch Start Setting). At the same time, the first ROIC 30A sets Rx channels based on the Rx setup information stored in the register (# 1 Touch Start Setting). When the # 1 SENSE READY OUT SET is received from the first ROIC 30A after the # 2 Touch Start Setting, the second ROIC 30B may generate a synchronization signal SYNC (# 2 SYNC OUT) to start sensing operation. The first ROIC 30A may start a sensing operation when the synchronization signal SYNC is received after the # 1 Touch Start Setting process.

The first ROIC 32 transmits a signal indicating that the sensing preparation is completed immediately after the # 1 Touch Start Setting process to the second ROIC 30B (# 1 SENSE READY OUT SET). When the second ROIC 30B receives the # 1 SENSE READY OUT SET signal, the second ROIC 30B transmits the synchronization signal SYNC to the first ROIC 30A, and feeds the synchronization signal SYNC to the touch timing generator 36b. By synchronizing the sensing operation of the internal circuit and the first ROIC (30A) (# 2 SYNC OUT). The second ROIC 30B supplies the driving signal to all the Tx lines Tx16 to Tx31 in charge of the driving signal immediately after the synchronization signal SYNC is output, and in synchronization with the driving signal, the Rx lines ( Rx28 to Rx54 receive the voltages of the touch sensors existing in the right half of the touch screen TSP and convert the voltages into touch raw data (# 2 Sensing Start). Tx lines Tx16 to Tx31 are formed at lower half portions B and D of the touch screen TSP. Rx lines Rx28 to Rx54 are formed on the right half portions C and D of the touch screen TSP. Since the first ROIC 30A does not output the driving signal while the driving signal is output from the second ROIC 30B, power consumption can be reduced. The first ROIC 30A is configured to display touch sensors existing in the left half portions A and C of the touch screen TSP through the Rx lines Rx1 to Rx27 in synchronization with the driving signal output from the second ROIC 30B. After receiving the voltage and converting it into the touch raw data (# 1 Sensing Start), after all the touch screen partitions in charge are sensed, the sensing is completed and transmitted to the second ROIC 30B and reset (# 1 SENSE READY). OUT RESET).

The first and second ROICs 30A when the sensing is completed for the entire sensing area of the touch screen TSP by scanning of all touch sensors of the touch screen TSP over the first and second sensing times Ts1 and Ts2. , 30B) sorts the touch raw data by a constant alignment method and transmits the touch raw data to the MCU 40.

ROICs 30A and 30B may be used alone. For example, in the case of the small touch screen TSP as shown in FIG. 11, if the number of Tx lines and Rx lines of the touch screen TSP is less than or equal to the number of Tx and Rx channels of the first or second ROIC, the touch is performed. The screen TSP may be driven by only one of the first or second ROICs 30A and 30B. In this case, the synchronization signal pin of the ROIC is in a floating state so that no external input signal is applied or the output signal of the timing controller 20 is applied to synchronize the display panel DIS. Therefore, since the present invention can drive touch screens (TSPs) having various sizes and resolutions using the same ROIC, the ROIC can be commonly used in various sizes of touch screens.

In the multi-chip driving method of the touch screen as shown in FIGS. 8 to 10, since the sensing operations of the touch screens are alternately processed in the ROICs 30A and 30B, the sensing time is longer when sensing the touch screen (TSP) with one ROIC. Can be long. Therefore, the multi-chip driving method as shown in FIGS. 8 to 10 reduces the touch report rate by controlling the ROICs 30A and 30B by the parallel processing method as shown in FIG. 7. The DMAs of the ROICs 30A and 30B store the touch raw data in the buffer memory and simultaneously read previous touch raw data from the buffer memory and transmit the same to the MCU 40 to enable parallel processing as shown in FIG. 7.

12 is a block diagram showing ROICs 30A and 30B in detail.

Referring to FIG. 12, each of the ROICs 30A and 30B includes the driving units 32a and 32b, the sensing units 34a and 34b, the touch timing generating units 36a and 36b, the DMA controllers 72a and 72b, and the buffer memory. 74a, 74b, data transmitters 76a, 76b, and the like.

The drivers 32a and 32b set a Tx channel to which a drive signal is supplied under the control of the touch timing generators 36a and 36b, and supply a drive signal to Tx lines connected to the set Tx channel. The sensing units 34a and 34b set an Rx channel to receive the touch sensor voltage under the control of the touch timing generators 36a and 36b and receive the voltage of the touch sensor through the Rx lines connected to the set Rx channel. The sensing units 34a and 34b convert the voltage of the received touch sensor into touch raw data TData1 and TData2 which are digital data.

When the NMIs (NMI_1, NMI_2) are received from the MCU 40, the touch timing generators 36a and 36b generate Tx setup and Rx setup signals SUTx and SURx to output driving signals and touch sensor voltages. Set the Rx channel to receive. The Tx switch array St connects the Tx channels and the Tx lines of the drivers 32a and 32b in response to the Tx setup signal SUTx. The Rx switch array Sr connects the Tx channels and the Tx lines of the drivers 32a and 32b in response to the Tx setup signal SUTx. The touch timing generators 36a and 36b transmit the touch raw data TData1 and TData2 output from the sensing units 34a and 34b to the DMA controllers 72a and 72b.

The DMA controllers 72a and 72b write the touch raw data TData1 and TData2 input from the sensing units 34a and 34b to the buffer memories 74a and 74a to sort the data TData1 and TData2. At the same time, the DMA controllers 72a and 72b read the previous touch raw data TData1 and TData2 from the buffer memories 74a and 74b and transfer them to the data transmitters 76a and 76b to perform parallel processing as shown in FIG. Implement The data transmitters 76a and 76b transmit the touch raw data TData1 and TData2 to the MCU 40 through standard serial interfaces such as SPI, I2C, and USB.

The MCU 40 includes first and second data receivers 82a and 82b, first and second DMA controllers 84a and 84b, a buffer memory 86, a microprocessor 88, and the like.

The first data receiver 82a transmits the touch raw data TData1 received from the first ROIC 30A to the first DMA controller 84a. The second data receiver 82b transmits the touch raw data TData2 received from the second ROIC 30B to the second DMA controller 84b. The first DMA controller 84a stores the touch raw data TData1 in the buffer memory 86, reads the touch raw data TData1 from the buffer memory 86, and transmits the touch raw data TData1 to the microprocessor 88. The second DMA controller 84b stores the touch raw data TData2 in the buffer memory 86, reads the touch raw data TData2 from the buffer memory 86, and transmits the touch raw data TData2 to the microprocessor 88. The first and second DMA controllers 84a and 84b read coordinate information XY of the touch input data from the buffer memory 86 and transmit the coordinate information XY to the host system 50 through a data transmitter not shown. The microprocessor 88 executes a preset touch recognition algorithm.

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
30, 30A, 30B: ROIC 40: MCU

Claims (4)

A ROIC configured to sense touch inputs by driving touch sensors to sense voltage changes of the touch sensors; And
And analyzing the touch raw data received from the ROIC and calculating a coordinate of each touch input,
The ROIC is,
A sensing unit which senses a voltage change of the touch sensor and outputs touch raw data;
A buffer memory in which the touch raw data is stored;
A data transmitter for transmitting the touch raw data to the MCU; And
And a memory controller for storing the touch raw data input from the sensing unit in the buffer memory and simultaneously reading previous touch raw data from the buffer memory and supplying the touch raw data to the data transmitter. Touch sensing system. The method of claim 1,
During the Nth frame period, the ROIC receives the voltages of the touch sensors and simultaneously transmits the touch raw data obtained as a result of sensing in the N-1th frame period to the MCU.
And the MCU calculates coordinates of the touch input by analyzing touch raw data received from the ROIC using a preset touch recognition algorithm during the Nth frame period. First and second ROICs which drive the touch sensors to sense voltage changes of the touch sensors to sense a touch input; And
An MCU which analyzes touch raw data received from the first and second ROICs and calculates coordinates of each of the touch input positions;
Each of the first and second ROICs,
A sensing unit which senses a voltage change of the touch sensor and outputs touch raw data;
A buffer memory in which the touch raw data is stored;
A data transmitter for transmitting the touch raw data to the MCU; And
And a memory controller for storing the touch raw data input from the sensing unit in the buffer memory and simultaneously reading previous touch raw data from the buffer memory and supplying the touch raw data to the data transmitter.
And the first and second ROICs receive a voltage of the touch sensors by alternately supplying a driving signal to the touch sensors in charge thereof while transmitting and receiving a synchronization signal through one pin. The method of claim 3, wherein
Each of the first and second ROICs receives the voltage of the touch sensors during the Nth frame period, and simultaneously transmits the touch raw data obtained as a result of sensing in the N-1th frame period to the MCU.
And the MCU calculates coordinates of the touch input by analyzing touch raw data received from the first and second ROICs using a preset touch recognition algorithm during the Nth frame period.

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