KR20140072313A - Touch sensing system - Google Patents

Abstract

The present invention relates to a touch sensing system. The touch sensing system includes: a driving unit which supplies a driving signal to a touchscreen; and a sensing unit which is synchronized with the driving signal to receive electric charges from touch sensors of the touchscreen. The electric charges are received from the touch sensors through Rx lines connected to a first sensing block and a third sensing block as the first and third sensing blocks are driven sequentially. Rx lines connected to a second sensing block arranged between the first and third sensing blocks are discharged while the first and third sensing blocks are being driven.

Description

Touch sensing system {TOUCH SENSING SYSTEM}

The present invention relates to a touch sensing system.

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

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

The mutual capacitive touch screen includes Tx lines, Rx lines that are orthogonal to Tx lines, and touch sensors formed between Tx lines and Rx lines. The sensing circuit supplies a driving signal to the Tx line and at the same time senses the voltage change of the touch sensor through the Rx line. The sensing circuit senses a change in the charge amount of the touch sensor before and after the touch, and determines whether or not the conductive material touches the touch screen and its position. This sensing circuit is integrated in an integrated circuit called ROIC (Readout Integrated Circuit) and connected to the touch screen.

When receiving the charge of the touch sensor through the Rx lines by supplying the driving signal to the Tx lines of the touch screen, the charge of the touch sensor can be received through the Rx lines in the state where the residual charge is not discharged to the Rx lines. In this case, due to the residual charge of the Rx lines, the current of the received signal becomes abnormal (Abnormal), which may lower the sensitivity of the touch screen and cause malfunction.

The present invention provides a touch sensing system capable of sensing a 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 driver for supplying a driving signal to a touch screen; And a sensing unit for receiving charge from the touch sensors of the touch screen in synchronization with the driving signal.

The sensing unit includes sensing blocks for simultaneously receiving charges of the touch sensor through I (I is a positive integer equal to or greater than 2) Rx lines.

The first sensing block and the third sensing block are sequentially driven to receive charges from the touch sensors through the Rx lines connected to the first and third sensing blocks.

While the first and third sensing blocks are driven, the 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, the present invention can prevent a peak current received at the sensing unit due to the residual charge of the Rx lines, thereby enhancing the sensitivity of the touch input and preventing malfunction of the touch screen.

1 is a block diagram illustrating a touch sensing system according to an embodiment of the present invention.
FIG. 2 is an enlarged plan view of a part of the touch screen shown in FIG. 1. FIG.
3 to 5 are views showing various combinations of the touch screen and the display panel.
6 is a diagram illustrating the configuration of the sensing unit shown in FIG.
7 is a diagram illustrating an example in which an abnormal peak current flows into the sensing blocks when the charge of the touch sensor is continuously sensed through neighboring sensing blocks.
8 to 14 are block diagrams illustrating 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 can be applied to a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an organic light emitting display , OLEDs, and electrophoresis (EPD) devices. In the following embodiments, a display device is described 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 a liquid crystal display device.

The touch sensing system of the present invention can 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 in terms of an equivalent circuit. Capacitance can be divided into Self Capacitance or 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. In the following embodiments, a mutual capacitance type touch screen is exemplified, but it should be noted that the touch sensing system of the present invention is not limited to the mutual capacitance type touch screen.

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.

1 to 5, 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 may be bonded onto the upper polarizer POL1 of the display panel DIS as shown in FIG. 3 or may be formed between the upper polarizer POL1 of the display panel DIS and the upper substrate GLS1 as shown in FIG. . 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. In Fig. 3 to Fig. 5, "PIX" means a pixel electrode of a liquid crystal cell, "GLS2" means a lower substrate, and "POL2" means a lower polarizer.

The display panel (DIS) has a liquid crystal layer formed between two substrates. The pixel array of the display panel DIS includes pixels formed in the pixel region defined by the data lines (D1 to Dm, m is a positive integer) and the gate lines (G1 to Gn, n is a positive integer) . Each of the pixels is connected to TFTs (Thin Film Transistors) formed at intersections of the data lines D1 to Dm and the gate lines G1 to Gn, a pixel electrode for charging a data voltage, A storage capacitor (Cst) for maintaining the voltage, and the like.

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 with a color filter on TFT (COT) structure. In this case, the black matrix and the color filter can 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 substrate or the lower substrate of the display panel DIS. On the upper substrate and the lower substrate of the display panel DIS, a polarizing plate is attached, and an alignment film for forming a pre-tilt angle of the liquid crystal on the inner surface in contact with the liquid crystal is formed. A column spacer for maintaining a cell gap of the liquid crystal cell is formed between the upper substrate and the lower substrate of the display panel DIS.

The liquid crystal mode of the display panel DIS can be realized by any known liquid crystal mode such as TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, IPS (In Plane Switching) mode and FFS . A backlight unit may be disposed below the rear surface of the display panel DIS. The backlight unit is implemented as an edge type or direct type backlight unit, and irradiates the display panel (DIS) with light.

The display driving circuit includes a data driving circuit 12, a scan driving circuit 14, and a timing controller 20, and writes the video data voltage of the input image to the pixels of the display panel DIS. The data driving circuit 12 converts the digital video data RGB input from the timing controller 20 into an analog positive / negative gamma compensation voltage to output 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 a scan pulse) synchronized with the data voltage to the gate lines G1 to Gn to select a line of the display panel DIS to which the data voltage is written.

The timing controller 20 inputs a timing signal such as a vertical synchronizing signal Vsync, a horizontal synchronizing signal Hsync, a data enable signal DE and a main clock MCLK input from the host system 50 And synchronizes the operation timings of the data driving circuit 12 and the scan driving circuit 14 with each other. The scan timing control signal includes a gate start pulse (GSP), a gate shift clock, a gate output enable signal (GOE), and the like. The data timing control signal includes a source sampling clock (SSC), a polarity control signal (Polarity), a source output enable signal (SOE), and the like.

The 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) with a built-in scaler to convert the digital video data RGB of the input image into a format suitable for display on the display panel DIS. The host system 50 transmits timing signals (Vsync, Hsync, DE, MCLK) to the timing controller 20 together with the digital video data. Further, 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 smaller than n), Rx lines Rx1 to RxM, M intersecting the Tx lines Tx1 to TxN, And MxN 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 capacities.

The ROIC 30 includes a driving unit 32, a sensing unit 34, a touch timing generating unit 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 voltages of the touch sensors through the Rx lines Rx1 to RxM in synchronization with the driving signals do. The ROIC 30 converts the received charge amount change of the touch sensor to touch raw data, which is digital data, using an analog-to-digital converter (ADC) 40). The driving signal can be generated in various forms such as a pulse, a sinusoidal wave, and a triangular wave.

The driving unit 32 selects a Tx channel to output a driving signal under the control of the touch timing generating unit 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 section of the driving signal to supply charge to the touch sensors Cts and are discharged in the low potential section of the driving signal. The driving signal is supplied to the Tx lines Tx1 to TxN so that the voltage of the touch sensors Cts can be accumulated in the capacitors of the integrator built in the sensing unit 34 through the Rx lines Rx1 to RxM As shown in Fig.

The sensing unit 34 sets the Rx channel under the control of the touch timing generator 38 and outputs the voltage of the touch sensor through the Rx lines Rx (i) and Rx (i + 1) connected to the Rx channel . The sensing unit 34 converts the voltage of the received touch sensor into digital data through the ADC to output touch raw data.

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

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

The MCU 40 executes a preset touch recognition algorithm. Any known algorithm for the touch recognition algorithm is possible. The touch recognition algorithm compares the touch primitive data input from the sensing unit 34 with a predetermined threshold value, and determines that the touch primitive data exceeding the threshold value is the 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 of a threshold value or more and calculates coordinates of each of the touch input positions. The MCU 40 transmits the identification code and the coordinate information XY of each of the touch input data to the host system 50. [

6 is a diagram illustrating the configuration of the sensing unit shown in FIG.

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 supplies the sampled voltage to the sixth Rx line Rx1, (Rx6) are sequentially supplied to the first ADC (ADC1). The first ADC ADC1 sequentially converts the charges of the first through 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 the twelfth Rx lines Rx7 to Rx12 in synchronization with the driving signal, (Rx12) are sequentially supplied to the second ADC (ADC2). The second ADC (ADC2) sequentially converts the 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 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 the charge of 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 (Rx7) increases. This is because of parasitic capacitance between the sixth and seventh Rx lines Rx6 and Rx7. Accordingly, immediately after the charge of the touch sensor is received through the first sensing block SU1, the second sensing block SU2 is driven to charge the touch sensor through the seventh to twelfth Rx lines Rx7 to Rx12 The residual charge is added to the charge of the touch sensor received through the seventh Rx line as shown in FIG. 7, and a peak current appears. The present invention drives the sensing blocks SU1 to SU7 by the interlace sensing method as shown in FIGS. 8 to 14 to receive the charge of the touch sensor after the residual charge of the Rx lines Rx1 to Rx42 is discharged. The interlace sensing method can sequentially drive the sensing blocks spaced apart by one or more sensing blocks without deteriorating the sensing speed, thereby securing the discharging time of the Rx lines connected to the sensing block therebetween. The driving sequence of the sensing blocks SU1 to SU7 is controlled by the touch timing generator 38. [

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

The interlaced sensing method of the present invention is a method of sensing interlaced 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, (SU2, SU4, SU5, and SU7) sequentially in the order of the sixth sensing block SU6, the fourth sensing block SU4, and the second sensing block SU2, SU4, and SU6) can be sequentially driven. While the odd-numbered sensing blocks SU1, SU3, SU5, and SU7 are driven, the residual charges of the Rx lines connected to the odd-numbered sensing blocks are discharged, while the odd-numbered sensing blocks SU2, SU4, and SU6 are driven Residual charges of the Rx lines connected to the odd-numbered sensing blocks are discharged.

As shown in FIG. 9, the interlace sensing method of the present invention includes a first sensing block SU1, a third sensing block SU3, a fifth sensing block SU5, and a seventh sensing block SU7, (SU2, SU4, SU5, and SU7) sequentially in the order of the second sensing block SU2, the fourth sensing block SU4, and the sixth sensing block SU6, SU4, and SU6) can be sequentially driven. The interlaced sensing method of the present invention is a method of sensing interlaced sensing blocks SU2, SU4, and SU6 in the order of a second sensing block SU2, a fourth sensing block SU4, and a sixth sensing block SU6, SU3 and SU7 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 after sequentially driving the odd sensing blocks SU1, SU5, and SU7) can be sequentially driven.

The interlace sensing method of the present invention is a method of sensing the odd numbered sensing blocks SU3, SU5, and SU7 in the order of the third sensing block SU3, the fifth sensing block SU5, and the seventh sensing block SU7, Sequentially drives the odd sensing blocks SU2, SU4 and SU6 in the order of the second sensing block SU2, the fourth sensing block SU4 and the sixth sensing block SU6 , And finally drives the first sensing block SU1. The interlaced sensing method of the present invention sequentially drives the odd 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, (SU1, SU3, SU5, and SU7) sequentially 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 , And finally the second sensing block SU2.

The interlaced sensing method of the present invention sequentially drives odd-numbered sensing blocks SU5 and SU7 in the order of a fifth sensing block SU5 and a seventh sensing block SU7 as shown in FIG. 13, SU2, SU4 and SU6 sequentially in the order of the first sensing block SU2, the fourth sensing block SU4 and the sixth sensing block SU6, (SU1, SU3). 14, after driving the sixth sensing block SU6, the first sensing block SU1, the third sensing block SU3, the fifth sensing block SU5, the seventh sensing block SU5, 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 driven last.

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.

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

Claims (3)

A driving unit for supplying driving signals to the touch screen; And
And a sensing unit for receiving charge from the touch sensors of the touch screen in synchronization with the driving signal,
Wherein the sensing unit includes sensing blocks for simultaneously receiving charges of a touch sensor through I (I is a positive integer equal to or greater than 2) Rx lines,
The first sensing block and the third sensing block are sequentially driven to receive charges from the touch sensors through Rx lines connected to the first and third sensing blocks,
And Rx lines connected to the second sensing block disposed between the first and third sensing blocks are discharged while the first and third sensing blocks are driven. The method according to claim 1,
The sensing blocks,
After the odd-numbered sensing blocks are sequentially driven, the odd-numbered sensing blocks are sequentially driven,
While the odd-numbered sensing blocks are sequentially driven, Rx lines connected to the odd-numbered sensing blocks are discharged,
And the Rx lines connected to the odd-numbered sensing blocks are discharged while the odd-numbered sensing blocks are sequentially driven. The method according to claim 1,
The sensing blocks,
After the odd-numbered sensing blocks are sequentially driven, the odd-numbered sensing blocks are sequentially driven,
While the odd-numbered sensing blocks are sequentially driven, Rx lines connected to the odd-numbered sensing blocks are discharged,
And the Rx lines connected to the odd-numbered sensing blocks are discharged while the odd-numbered sensing blocks are sequentially driven.

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