KR102143945B1 - Touch sensing system - Google Patents

Abstract

The present invention relates to a touch sensing system, comprising: a driving unit for supplying a driving signal to a touch screen; And a sensing unit receiving electric charges from touch sensors of the touch screen in synchronization with the driving signal. The first sensing block and the third sensing block are sequentially driven to receive electric charges from the touch sensors through Rx lines connected to the first and third sensing blocks. While the first and third sensing blocks are being driven, Rx lines connected to the second sensing block disposed between the first and third sensing blocks are discharged.

Description

Touch sensing system {TOUCH SENSING SYSTEM}

The present invention relates to a touch sensing system.

The user interface (UI) allows a person (user) to easily control various 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 an infrared or radio frequency (RF) communication function. User interface technology is constantly evolving in the direction of enhancing user sensitivity and operational convenience. Recently, user interfaces are evolving into touch UIs, voice recognition UIs, and 3D UIs.

Touch UI is essentially adopted in portable information devices. The touch UI is implemented by forming a touch screen on the 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 driving signal to the Tx line and at the same time detects a voltage change of the touch sensor through the Rx line. The sensing circuit detects a change in the amount of electric charge of the touch sensor before and after the touch, and determines whether or not the conductive material touches the touch screen and its location. This sensing circuit is integrated in an integrated circuit called a ROIC (Readout Integrated Circuit) and connected to the touch screen.

When a driving signal is supplied to the Tx lines of the touch screen to receive the charge from the touch sensor through the Rx lines, the charge from the touch sensor may be received through the Rx lines while the residual charge is not discharged from the Rx lines. In this case, due to the residual charge of the Rx lines, the current of the received signal is abnormally increased, which lowers the sensitivity of the touch screen and may cause a malfunction.

The present invention provides a touch sensing system capable of sensing charge of a touch sensor by securing a residual charge discharge time of an Rx line.

The touch sensing system of the present invention includes a driving unit for supplying a driving signal to a touch screen; And a sensing unit receiving electric charges from touch sensors of the touch screen in synchronization with the driving signal.
The sensing unit includes three or more sensing blocks.
Each of the sensing blocks includes first, second, and third sensing blocks connected to I (I is a positive integer greater than or equal to 2) Rx lines.
The first sensing block simultaneously receives and samples electric charges from the touch sensor through I neighboring Rx lines in the first Rx group, and sequentially outputs the sampled voltage. The second sensing block simultaneously receives and samples charges from the touch sensor through I adjacent Rx lines in the second Rx group, and sequentially outputs the sampled voltage. The third sensing block simultaneously receives and samples charges from the touch sensor through I adjacent Rx lines in the third Rx group, and sequentially outputs the sampled voltage.
The first sensing block and the third sensing block are sequentially driven to receive electric charges from touch sensors through Rx lines connected to the first and third sensing blocks.

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While the first and third sensing blocks are being driven, Rx lines connected to the second sensing block disposed between the first and third sensing blocks are discharged.

According to the present invention, the charge of the touch sensor can be sensed by securing the residual charge discharge time of the Rx line without lowering the sensing speed by using the interlace sensing method. As a result, according to the present invention, it is possible to increase the sensitivity of a touch input and prevent malfunction of the touch screen by preventing a peak current received by the sensing unit due to residual charge of the Rx lines.

1 is a block diagram showing a touch sensing system according to an embodiment of the present invention.
2 is an enlarged plan view of a part of the touch screen shown in FIG. 1.
3 to 5 are diagrams showing various combinations of a touch screen and a display panel.
6 is a diagram showing a configuration of a sensing unit shown in FIG. 1.
FIG. 7 is a diagram illustrating an example in which an abnormal peak current flows into sensing blocks when electric charges of a touch sensor are continuously sensed through neighboring sensing blocks.
8 to 14 are block diagrams showing examples of interlace sensing methods of a touch sensing system according to an embodiment of the present invention.

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 electrophoresis display devices (Electrophoresis, EPD). In the following embodiments, a display device as an example of a flat panel display device is described with a focus on a liquid crystal display device, but the display device of the present invention is not limited to a 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 capacitance when viewed as an equivalent circuit. Capacitance may be divided into self-capacitance or mutual capacitance. The self-capacitance is formed along single-layer conductor wiring formed in one direction. Mutual capacitance is formed between two orthogonal conductor wires. In the following embodiments, a mutual capacitive touch screen is illustrated, but it should be noted that the touch sensing system of the present invention is not limited to a mutual capacitive touch screen.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals throughout the specification mean substantially the same elements. In the following description, when it is determined that a detailed description of a known function or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

Referring to FIGS. 1 to 5, the touch sensing system of the present invention includes a touch screen (TSP), ROIC 30, 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. 3 or formed between the upper polarizing plate POL1 and the upper substrate GLS1 of the display panel DIS as shown in FIG. 4. Can be. Also, the touch sensors Cts of the touch screen TSP may be embedded in the lower substrate in an in-cell type together with a pixel array in the display panel DIS as shown in FIG. 5. 3 to 5, "PIX" refers to a pixel electrode of a liquid crystal cell, "GLS2" refers to a lower substrate, and "POL2" refers to a lower polarizing plate.

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 a pixel area defined by data lines (D1 to Dm, m is a positive integer) and gate lines (G1 to Gn, n is a positive integer). . Each of the pixels is connected to TFTs (Thin Film Transistor) formed at the intersections of the data lines D1 to Dm and the gate lines G1 to Gn, a pixel electrode charging the data voltage, and a pixel electrode. It includes a storage capacitor (Cst) to maintain the voltage.

A black matrix, a color filter, 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 in 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 to which the common voltage is supplied may be formed on the upper or 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 a pretilt angle of the liquid crystal is formed on an inner surface in contact with the liquid crystal. 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 a twisted nematic (TN) mode, a vertical alignment (VA) mode, an in plane switching (IPS) mode, and a fringe field switching (FFS) mode. . A 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 and irradiates light to the display panel DIS.

The display driving circuit includes a data driving circuit 12, a scan driving circuit 14, and a timing controller 20 to write a video data voltage of an input image to pixels of the display panel DIS. The data driving circuit 12 converts 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 driving circuit 12 is supplied to the data lines D1 to Dm. The scan driving circuit 14 sequentially supplies a gate pulse (or scan pulse) synchronized with the data voltage to the gate lines G1 to Gn to select a line of the display panel DIS on which the data voltage is 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. Receive and synchronize the operation timing of the data driving circuit 12 and the scan driving circuit 14. The scan timing control signal includes a gate start pulse (GSP), a gate shift clock, a gate output enable signal (Gate Output Enable, 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 converts the digital video data RGB of the input image into a format suitable for display on the display panel DIS, including a system on chip (SoC) with a built-in scaler. The host system 50 transmits timing signals Vsync, Hsync, DE, and MCLK together with digital video data to the timing controller 20. In addition, the host system 50 executes an application program linked with coordinate information (XY) of touch data input from the MCU 40.

Tx lines (Tx1 to TxN, N is a positive integer smaller than n), and Rx lines (Rx1 to RxM, M are m) intersecting 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 a mutual capacitance.

The ROIC 30 includes a driving unit 32, a sensing unit 34, a touch timing generator 38, and the like. The ROIC 30 applies a driving signal to the touch sensors Cts through the Tx lines (Tx1 to TxN), and receives the voltage of the touch sensors through the Rx lines (Rx1 to RxM) in synchronization with the driving signal. do. In addition, the ROIC 30 converts the change in the amount of charge of the received touch sensor into touch raw data, which is digital data, using an analog to digital converter (hereinafter referred to as “ADC”), 40). The driving signal may be generated in various forms such as pulses, sinusoids, and triangle waves.

The driver 32 selects a Tx channel to output a driving signal under the control of the touch timing generator 38 and applies a driving signal to the 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, supply electric charges to the touch sensors Cts, and discharged in the low potential period of the driving signal. The driving signal is each of the Tx lines Tx1 to TxN so that the voltage of the touch sensors Cts can be accumulated in the capacitor of the integrator built into the sensing unit 34 through the Rx lines Rx1 to RxM. Can be supplied continuously.

The sensing unit 34 sets the Rx channel under the control of the touch timing generator 38, and controls the voltage of the touch sensor through the Rx lines (Rx(i), 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 an ADC and outputs touch raw data.

The sensing unit 34 may simultaneously receive electric charges from the touch sensor through a plurality of Rx channels in units of sensing blocks as shown in FIGS. 6 to 14. One sensing block is connected to I (I is a positive integer of 2 or more and M/2 or less) Rx lines, and simultaneously receives electric charges from the touch sensor through I Rx lines in synchronization with a driving signal. In the following embodiment, an example in which six Rx lines are connected to one sensing block will be described, but the present invention is not limited thereto. As shown in FIG. 2, the sensing unit 34 determines the time during which residual charges accumulated in the Rx lines Rx1 to RxM can be discharged due to the parasitic capacitance (FIG. 2, C12 to C45) between the Rx lines Rx1 to RxM In order to secure it, the electric charge of the touch sensor is sensed by the interlace sensing method as shown in FIGS. 8 to 14.

The touch timing generator 38 controls Tx channel and Rx channel settings and synchronizes the driving unit 32 and the sensing unit 34.

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

6 is a diagram showing a configuration of a sensing unit shown in FIG. 1.

Referring to FIG. 6, the sensing unit 34 includes a plurality of sensing blocks SU1 to SU7 and a plurality of ADCs ADC1 to ADC7.

Each of the sensing blocks SU1 to SU7 is connected to six Rx lines, and is connected to one ADC (ADC1 to ADC7). The first sensing block SU1 simultaneously receives and samples the voltage of the touch sensor through the first to sixth Rx lines Rx1 to Rx6 in synchronization with the driving signal, and the first Rx line Rx1 to the sixth Rx line The voltages sampled in the order of (Rx6) are sequentially supplied to the first ADC (ADC1). The first ADC ADC1 sequentially converts charges of the first to sixth touch sensors supplied from the first sensing block SU1 into digital data and outputs touch raw data. The second sensing block SU2 simultaneously receives and samples the voltage of the touch sensor through the seventh to twelfth Rx lines Rx7 to Rx12 in synchronization with the driving signal, and the seventh Rx line Rx7 to the 12th Rx line The voltages sampled in the order of (Rx12) are sequentially supplied to the second ADC (ADC2). The second ADC (ADC2) sequentially converts charges of the seventh to twelfth touch sensors supplied from the second sensing block (SU2) into digital data and outputs touch raw data. In this way, each of the sensing blocks SU1 to SU7 simultaneously senses the electric charge of the touch sensor through a plurality of Rx lines.

When neighboring sensing blocks are continuously driven as shown in FIG. 7, an abnormal current may flow into the sensing blocks. For example, when the first sensing block SU1 receives charge from the touch sensor through the first to sixth Rx lines Rx1 to Rx6 in synchronization with the driving signal, the seventh Rx line adjacent to the sixth Rx line The residual charge of (Rx7) increases. This is due to the parasitic capacitance between the sixth and seventh Rx lines Rx6 and Rx7. Accordingly, immediately after receiving the charge from the touch sensor through the first sensing block SU1, the second sensing block SU2 is driven and the charge of the touch sensor through the seventh to twelfth Rx lines Rx7 to Rx12 Upon reception, as shown in FIG. 7, residual charge is added to the charge of the touch sensor received through the seventh Rx line, resulting in a peak current. According to an exemplary embodiment of the present invention, the sensing blocks SU1 to SU7 are driven by the interlace sensing method as shown in FIGS. 8 to 14 to receive the charge of the touch sensor after the residual charges of the Rx lines Rx1 to Rx42 are discharged. In the interlace sensing method, without deteriorating the sensing speed, the sensing blocks spaced apart with one or more sensing blocks interposed therebetween may be sequentially driven to secure discharge time of Rx lines connected to the sensing blocks therebetween. The driving order of the sensing blocks SU1 to SU7 is controlled by the touch timing generator 38.

8 to 14 are block diagrams showing examples of interlace sensing methods of a touch sensing system according to an embodiment of the present invention.

The interlace sensing method of the present invention includes odd-numbered sensing blocks in the order of a seventh sensing block SU7, a fifth sensing block SU5, a third sensing block SU3, and a first sensing block SU1, as shown in FIG. 8. After sequentially driving (SU1, SU3, SU5, SU7), the even-th sensing blocks SU2, in the order of the sixth sensing block SU6, the fourth sensing block SU4, and the second sensing block SU2, SU4, SU6) can be driven sequentially. While the odd-numbered sensing blocks SU1, SU3, SU5, and SU7 are driven, the residual charges of the Rx lines connected to the even-numbered sensing blocks are discharged, while the even-numbered sensing blocks SU2, SU4, and SU6 are driven. The residual charge of the Rx lines connected to the odd-numbered sensing blocks is discharged.

The interlace sensing method of the present invention includes odd-numbered sensing blocks in the order of a first sensing block SU1, a third sensing block SU3, a fifth sensing block SU5, and a seventh sensing block SU7, as shown in FIG. 9. After sequentially driving (SU1, SU3, SU5, SU7), the second sensing block SU2, the fourth sensing block SU4, and the sixth sensing block SU6 in the order of the even-th sensing blocks SU2, SU4, SU6) can be driven sequentially. In the interlace sensing method of the present invention, as shown in FIG. 10, the second sensing block SU2, the fourth sensing block SU4, and the sixth sensing block SU6 are in the order of the eventh sensing blocks SU2, SU4, and SU6. After sequentially driving, the odd-numbered sensing blocks SU1 and SU3, in the order of the first sensing block SU1, the third sensing block SU3, the fifth sensing block SU5, and the seventh sensing block SU7, SU5, SU7) can be driven sequentially.

The interlace sensing method of the present invention comprises odd-numbered sensing blocks SU3, SU5, and SU7 in the order of a third sensing block SU3, a fifth sensing block SU5, and a seventh sensing block SU7, as shown in FIG. After sequentially driving, the second sensing block SU2, the fourth sensing block SU4, and the sixth sensing block SU6 are sequentially driven in order of the even-th sensing blocks SU2, SU4, and SU6. , Finally, the first sensing block SU1 may be driven. In the interlace sensing method of the present invention, after sequentially driving the even-th sensing blocks SU4 and SU6 in the order of the fourth sensing block SU4 and the sixth sensing block SU6 as shown in FIG. 12, the first sensing block The odd-numbered sensing blocks SU1, SU3, SU5, and SU7 are sequentially driven in the order of (SU1), the third sensing block (SU3), the fifth sensing block (SU5), and the seventh sensing block (SU7). , Finally, the second sensing block SU2 may be driven.

In the interlace sensing method of the present invention, after sequentially driving the odd-numbered sensing blocks SU5 and SU7 in the order of the fifth sensing block SU5 and the seventh sensing block SU7, as shown in FIG. 13, the second sensing block (SU2), the fourth sensing block (SU4), the sixth sensing block (SU6) sequentially drives the even-th sensing blocks (SU2, SU4, SU6), and finally, the first and third sensing blocks (SU1, SU3) can be driven. In the interlace sensing method of the present invention, after driving the sixth sensing block SU6 as shown in FIG. 14, the first sensing block SU1, the third sensing block SU3, the fifth sensing block SU5, and the seventh sensing The odd-numbered sensing blocks SU1, SU3, SU5, and SU7 may be sequentially driven in the order of the block SU7, and then the second and fourth sensing blocks SU2 and SU4 may be finally driven.

It will be appreciated by those skilled in the art through the above description that various changes and modifications can be made without departing from the technical idea of the present invention. Therefore, the technical scope of the present invention should not be limited to the content described in the detailed description of the specification, but should be determined by the claims.

DIS: Display panel TSP: Touch screen
12: data driving circuit 14: scan driving circuit
30: ROIC 40: MCU
SU1~SU7: sensing block

Claims (4)

A touch screen including Tx lines and Rx lines intersecting each other;
A driver supplying a driving signal to the Tx lines; And
A sensing unit for receiving electric charges from touch sensors of the touch screen through the Rx lines in synchronization with the driving signal,
The sensing unit includes three or more sensing blocks,
Each of the sensing blocks includes first, second, third and fourth sensing blocks connected to I (I is a positive integer of 2 or more) Rx lines,
The first sensing block simultaneously receives and samples the charge of the touch sensor through I adjacent Rx lines in the first Rx group, and sequentially outputs the sampled voltage,
The second sensing block simultaneously receives and samples the charge of the touch sensor through I adjacent Rx lines in the second Rx group, and sequentially outputs the sampled voltage,
The third sensing block simultaneously receives and samples the charge of the touch sensor through I adjacent Rx lines in the third Rx group, and sequentially outputs the sampled voltage,
The fourth sensing block simultaneously receives and samples the charge of the touch sensor through I adjacent Rx lines in the fourth Rx group, and sequentially outputs the sampled voltage,
The first sensing block and the third sensing block are sequentially driven to receive electric charges from touch sensors through Rx lines connected to the first and third sensing blocks,
Rx lines connected to the second sensing block between the first and third sensing blocks are discharged while the first and third sensing blocks are being driven,
The second sensing block and the fourth sensing block are sequentially driven to receive electric charge from touch sensors through Rx lines connected to the second and fourth sensing blocks,
The touch sensing system, wherein Rx lines connected to the third sensing block between the second and fourth sensing blocks are discharged while the second and fourth sensing blocks are being driven. The method of claim 1,
The sensing blocks,
After the odd-numbered sensing blocks are sequentially driven, the even-numbered sensing blocks are sequentially driven,
While the odd-numbered sensing blocks are sequentially driven, Rx lines connected to the even-numbered sensing blocks are discharged,
While the even-numbered sensing blocks are sequentially driven, Rx lines connected to the odd-numbered sensing blocks are discharged. The method of claim 1,
The sensing blocks,
After the even-numbered sensing blocks are sequentially driven, the odd-numbered sensing blocks are sequentially driven,
While the even-numbered sensing blocks are sequentially driven, Rx lines connected to the odd-numbered sensing blocks are discharged,
While the odd-numbered sensing blocks are sequentially driven, Rx lines connected to the even-numbered sensing blocks are discharged. The method of claim 1,
Further comprising a plurality of analog-to-digital converters (ADCs) arranged one per block in the sensing unit,
The analog-to-digital converter,
A first analog-to-digital converter sequentially converting the I touch sensor voltages supplied from the first sensing block into digital data;
A second analog-to-digital converter sequentially converting the I touch sensor voltages supplied from the second sensing block into digital data; And
A touch sensing system comprising a third analog-to-digital converter that sequentially converts the I touch sensor voltages supplied from the third sensing block into digital data.

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