KR102009886B1 - Touch sensing display divice - Google Patents

Abstract

A touch sensing display device according to the present invention includes a display panel; A touch screen coupled to the display panel and having a plurality of sensor nodes formed by intersection of a plurality of Tx lines and a plurality of Rx lines; A Tx generator for generating an input Tx drive signal; A Tx compensation circuit configured to shift the input Tx drive signal based on a display control signal applied from the outside to generate a compensation Tx drive signal and to supply the Tx lines to the Tx lines; And an Rx driving circuit configured to receive and sample the voltages of the sensor nodes through the Rx lines, and to analog-digital convert the sampled sensor node voltages to generate touch raw data; The high section of the compensation Tx driving signal and the high section of the display control signal do not overlap each other.

Description

Touch Sensing Display {TOUCH SENSING DISPLAY DIVICE}

The present invention relates to a touch sensing display device, and more particularly, to a touch sensing display device capable of avoiding noise caused by an external signal.

In accordance with the trend toward lighter and slimmer home appliances and portable information devices, user input means are being replaced by touch screens from button switches. The touch screen refers to a screen that directly touches and inputs a screen without the need for another input device. The use of the touch screen is expanding its use in overall IT products, starting with the mobile phone market.

The touch screen applied to the display device includes a plurality of touch sensors. The touch sensors may be implemented in a resistive type, a capacitive type, an electro magnetic type, and the like, and among them, the touched part may be detected by detecting a location where a change in capacitance occurs. Capacitive sensing is widely used.

As shown in FIG. 1, the capacitive touch sensors included in the touch screen 1 include a plurality of sensor nodes. Sensor nodes are formed at the intersection of multiple Tx lines and multiple Rx lines to form a mutual capacitor. The touch screen driving circuit 2 of FIG. 1 includes a Tx driving circuit for applying the Tx driving signal 4 to the Tx lines, and an Rx sensing signal 5 by sampling the voltage of the sensor node to which the Tx driving signal 4 is applied. ) And an Rx driving circuit for converting the digital data into touch raw data. The touch driving circuit 2 transmits touch raw data to the touch controller 3. The touch controller 3 recognizes a touch point by calculating a change amount of touch raw data of each sensor node before and after the touch.

In implementing the touch sensing display device, the touch screen 1 is not used independently but is used together with the display panel. The touch screen 1 may be built in an in-cell type in the display panel, or may be coupled to the display panel in an on-cell type or an add-on cell type. . Signal lines for driving pixels are formed in the display panel, and the signal lines are driven by a panel driving circuit operated based on display control signals applied from the outside. The display control signals have a certain periodicity, which causes noise in touch sensing. Such noise is generated in a section in which the high section H of the display control signal and the high section H of the Tx driving signal overlap each other, as shown in FIG. 2. The generated noise is mixed with the integrated value of the Rx sensing signal to reduce the touch sensitivity.

Accordingly, an object of the present invention is to provide a touch sensing display device capable of improving touch sensitivity by avoiding noise caused by display control signals.

In order to achieve the above object, a touch sensing display device according to an embodiment of the present invention is a display panel; A touch screen coupled to the display panel and having a plurality of sensor nodes formed by intersection of a plurality of Tx lines and a plurality of Rx lines; A Tx generator for generating an input Tx drive signal; A Tx compensation circuit configured to shift the input Tx drive signal based on a display control signal applied from the outside to generate a compensation Tx drive signal and to supply the Tx lines to the Tx lines; And an Rx driving circuit configured to receive and sample the voltages of the sensor nodes through the Rx lines, and to analog-digital convert the sampled sensor node voltages to generate touch raw data; The high section of the compensation Tx driving signal and the high section of the display control signal do not overlap each other.

The touch sensing display device according to the present invention may improve the touch sensitivity by avoiding the noise introduced by the display control signals by adjusting the generation timing of the high period of the compensation Tx driving signal so as not to overlap the high period of the display control signal. .

1 is a view schematically showing a conventional touch sensing display device;
2 is a diagram illustrating that noise is mixed in an Rx sensing signal in a high section in which a conventional display control signal and a Tx driving signal overlap each other;
3 illustrates a touch sensing display device according to an exemplary embodiment of the present invention.
4 to 6 illustrate various embodiments in which a touch screen is coupled to a display panel.
7 illustrates an example of generating a compensated Tx drive signal by shifting an input Tx drive signal.
8 shows a schematic operation of a Tx compensation circuit;
9 shows a detailed configuration of a Tx compensation circuit.
10 is a diagram for specifically describing an operation of a Tx compensation circuit.
FIG. 11 is a diagram illustrating a detailed configuration of the signal calculator of FIG. 9. FIG.
12 illustrates in detail the arithmetic operations performed in the signal operator.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 3 to 12.

3 illustrates a touch sensing display device according to an embodiment of the present invention. 4 to 6 are diagrams illustrating various embodiments in which a touch screen is coupled to a display panel. 7 illustrates an example of generating a compensation Tx driving signal by shifting an input Tx driving signal such that the high section of the compensation Tx driving signal and the high section of the display control signal do not overlap each other.

Referring to FIG. 3, a touch sensing display device according to an exemplary embodiment of the present invention may include a display panel DIS, display driving circuits 22 and 24, a timing controller 40, a touch screen TSP, and a touch screen driving circuit ( 30, 34, touch controller 36, and the like.

The touch-sensing 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) It may be implemented based on a flat panel display device such as an Emitting Display (OLED), an electrophoretic display device (Electrophoresis, EPD). In the following embodiments, the touch sensing display device will be described based on the liquid crystal display device. However, it should be noted that the touch sensing display device of the present invention is not limited to the liquid crystal display device.

In the display panel DIS, a liquid crystal layer is formed between two substrates. The lower substrate of the display panel DIS includes a plurality of data lines D1 to Dm and m are natural numbers, a plurality of gate lines G1 to Gn and n are natural numbers intersecting the data lines D1 to Dm. A plurality of TFTs formed at intersections of the data lines D1 to Dm and the gate lines G1 to Gn, a plurality of pixel electrodes for charging data voltages to liquid crystal cells, and a pixel electrode And a storage capacitor to maintain the voltage of the liquid crystal cell.

The pixels of the display panel DIS are formed in a pixel area defined by the data lines D1 to Dm and the gate lines G1 to Gn, and are arranged in a matrix form. The liquid crystal cell constituting each of the pixels is driven according to the voltage difference between the data voltage applied to the pixel electrode and the common voltage applied to the common electrode to adjust the transmission amount of incident light. The TFTs are turned on in response to gate pulses from the gate lines G1 to Gn to supply voltages from the data lines D1 to Dm to the pixel electrodes of the liquid crystal cell.

The upper substrate of the display panel DIS may include a black matrix, a color filter, and the like. The lower substrate of the display panel DIS may be implemented 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.

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 backlight unit may be disposed on 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 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 display driving circuit includes a data driving circuit 22 and a scan driving circuit 24 to write the video data voltage of the input image to the pixels. The data driving circuit 22 converts the digital video data RGB input from the timing controller 40 into an analog positive / negative gamma compensation voltage and outputs a data voltage. The data voltage is supplied to the data lines D1 to Dm. The scan driving circuit 24 sequentially supplies gate pulses (or scan pulses) synchronized with the data voltages to the gate lines G1 to Gn to select horizontal pixel lines of the display panel DIS to which the data voltages are written. .

The timing controller 40 inputs a display control signal 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 an external host system. And generates a data control signal for controlling the operation timing of the data driving circuit 22 and a gate control signal for controlling the operation timing of the scan driving circuit 24. The gate control signal includes a gate start pulse (GSP), a gate shift clock, a gate output enable signal (GOE), and the like. The data 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 touch screen TSP may be bonded to the upper polarizer POL1 of the display panel DIS as shown in FIG. 4, or may be formed between the upper polarizer POL1 and the upper substrate GLS1 as shown in FIG. 5. In addition, the touch screen TSP may be formed on 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.

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

The touch screen driving circuit supplies touch driving pulses to the Tx lines T1 to Tj and senses the voltage of the sensor node through the Rx lines R1 to Ri to convert the data into digital data. To this end, the touch screen driving circuit includes a Tx driving circuit 30 and an Rx driving circuit 34. The Tx driving circuit 30 and the Rx driving circuit 34 may be integrated in one read-out IC (ROIC).

The Tx driving circuit 30 shifts the pulse by shifting the input Tx driving signal Tx so as not to overlap the display control signal applied from the Tx generating circuit 31 which generates the input Tx driving signal Tx in the form of a pulse. And a Tx compensation circuit 32 for generating a compensation Tx driving signal Tx '. The display control signal is a timing control signal generated every one horizontal period, and may be selected from one of a horizontal synchronization signal Hsync and a data enable signal DE. The Tx compensation circuit 32 generates timings of the compensation Tx driving signal Tx 'such that the high section H of the compensation Tx driving signal Tx' does not overlap with the high section H of the display control signal as shown in FIG. 7. Adjust it.

The Tx driving circuit 30 sets a Tx channel to output the compensation Tx driving signal Tx 'in response to the setup signal input from the touch controller 36. The Tx driving circuit 30 supplies the compensation Tx driving signal Tx 'to the Tx lines T1 to Tj connected to the Tx channel set according to the setup signal every sensing time.

The Rx driver circuit 34 sets an Rx channel to receive the sensor node voltage in response to a setup signal input from the touch controller 36. The Rx driving circuit 34 receives the voltage of the sensor node through the Rx lines R1 to Ri connected to the Rx channel set according to the setup signal, and samples the voltage of the sensor node to generate the Rx sensing signal. The Rx driving circuit 34 converts the Rx sensing signal into touch raw data, which is digital data, during the analog-to-digital conversion time, and transmits it to the touch controller 36.

The touch controller 36 is connected to the Tx driving circuit 30 and the Rx driving circuit 34 through an interface such as an I 2 C bus, a serial peripheral interface (SPI), a system bus, or the like. The touch controller 36 supplies a setup signal to the Tx driving circuit 30 and the Rx driving circuit 34 to set the Tx channel to which the touch driving pulse is output and select the Rx channel to which the voltage of the sensor node is read. The touch controller 36 supplies a switch control signal for controlling the sampling timing of the sampling circuit built in the Rx driving circuit 34 to the Rx driving circuit 34 to control the sampling timing of the sensor node voltage. The touch controller 36 supplies an ADC clock to an analog-to-digital converter embedded in the Rx driving circuit 34 to control the digital conversion timing with respect to the sensor node voltage. The touch controller 36 receives touch raw data from the Rx driver circuit 34, binarizes the touch raw data, and executes a preset coordinate value extraction algorithm to calculate the touch coordinate value. The touch controller 36 compensates the calculated touch coordinate value according to the resolution of the display panel DIS, and transmits the compensated coordinate value P (x, y) to the external host system as digital touch data in HID format. do. The host system executes an application program associated with the coordinate values P (x, y) of the touch data input from the touch controller 36.

8 shows a schematic operation of the Tx compensating circuit 32.

Referring to FIG. 8, the Tx compensation circuit 32 detects a rising edge and a falling edge of a display control signal applied from the outside. The Tx compensation circuit 32 obtains the width Y of the row section L of the display control signal based on the rising edge and the falling edge of the display control signal. The Tx compensating circuit 32 detects the rising edge and the falling edge of the input Tx driving signal Tx applied from the Tx generating circuit 31 and based on the rising edge H of the high period H of the input Tx driving signal Tx. Find the width X. The Tx compensation circuit 32 shifts the Tx driving signal Tx appropriately so that the high section of the compensation Tx driving signal overlaps the width Y of the low section L of the display control signal. The Tx compensation circuit 32 determines Y / X to determine the number of high periods of the compensation Tx driving signal that overlap each row period L of the display control signal. Although not shown, the high period of the compensation Tx driving signal may correspond to the low period L of each display control signal.

9 shows a detailed configuration of the Tx compensating circuit 32. 10 is a diagram for explaining the operation of the Tx compensating circuit 32. FIG. 11 shows a detailed configuration of the signal calculator 329 of FIG.

Referring to FIG. 9, the Tx compensation circuit 32 may include a first rising edge detector 321, a first falling edge detector 322, a second rising edge detector 323, a second falling edge detector 324, and a first rising edge detector 321. One to fourth counters 325, 326, 327, 328, and a signal operator 329.

Referring to FIG. 10, the first rising edge detector 321 detects a rising edge Pds of a display control signal and supplies the rising edge Pds to the first and second counters 325 and 326. The first falling edge detector 322 detects the falling edge Fds of the display control signal and supplies the falling edge Fds to the second counter 326. The second rising edge detector 323 detects the rising edge Ptx of the input Tx driving signal Tx and supplies the rising edge Ptx to the third and fourth counters 327 and 328. The second falling edge detector 324 detects the falling edge Ftx of the input Tx driving signal Tx and supplies it to the fourth counter 328.

Referring to FIG. 10, the first counter 325 counts between neighboring rising edges Pds of the display control signal to determine a first counting value reg1 corresponding to one period width Tds of the display control signal. Create The second counter 326 counts between the neighboring rising edges Pds and the falling edge Fds of the display control signal to generate a second counting value reg2 corresponding to the high section H width Ths of the display control signal. ) The third counter 327 counts between neighboring rising edges Ptx of the input Tx driving signal to generate a third counting value reg3 corresponding to one period width Ttx of the input Tx driving signal. The fourth counter 328 counts between the neighboring rising edge Ptx and the falling edge Ftx of the input Tx driving signal to form a fourth counting value corresponding to the high section H width Thtx of the input Tx driving signal. Create (reg4).

The signal operator 329 is non-overlapping with the high section H of the display control signal based on the first to fourth counting values reg1, reg2, reg3, and reg4 input from the first to fourth counters 325, 326, 327, and 328. A compensation Tx driving signal Tx 'is generated. To this end, the signal calculator 329 includes first to fourth registers REG1 to REG4, a calculator 329A, and a Tx ′ generator 329B.

The first to fourth registers REG1 to REG4 store the first to fourth counting values reg1, reg2, reg3, and reg4 input from the first to fourth counters 325 to 328, respectively. The calculation unit 329A repeatedly counts the k (k is a natural number) of the display control signal from the kth falling edge (Fds) to the k + 1th rising edge (Pds) (that is, the row section L of the display control signal). The operation counter is built in, and the rising point and the falling point of the compensation Tx driving signal Tx 'that do not overlap the high section H of the display control signal are calculated and supplied to the Tx' generation unit 329B. The Tx 'generation unit 329B generates a compensation Tx driving signal Tx' that is non-overlapping with the high section H of the display control signal based on the rising point and the falling point applied from the calculating unit 329A.

12 shows in detail the computational operations performed in signal operator 329.

Referring to FIG. 12, the signal calculator 329 resets the operation count value corresponding to the width of the row section L of the display control signal to 0, and applies 1 to n multiplied by the fourth counting value reg4. Then, the compensation Tx driving signal Tx 'is generated high (S1).

The signal calculator 329 operates the operation counter to advance the count until the operation count value is equal to the fourth counting value reg4. (S2)

When the operation count value is equal to the fourth counting value reg4, the signal calculator 329 generates the compensation Tx driving signal Tx 'low.

The signal operator 329 operates the operation counter to count until the operation count value is equal to the fourth counting value reg4 * 2. (S4) The driving duty of the compensation Tx drive signal Tx 'is 50. %, The fourth counting value reg4 * 2 corresponds to one period width of the compensation Tx driving signal Tx '.

When the operation count value is equal to the fourth counting value reg4 * 2, the signal calculator 329 compares the operation count value with the 'first counting value reg1-the third counting value reg3' (S5). )

If the result of the comparison of S5 is less than or equal to the first counting value reg1 and the third counting value reg3, the signal calculator 329 generates the compensating Tx driving signal Tx high, 2 is applied to n to perform the operation again from step S2 (S6 and S7).

As a result of the comparison of S5, when the operation count value is greater than the first counting value reg1 and the third counting value reg3, the signal calculator 329 counts until the operation count value becomes the first counting value reg1. In operation S8 and S9, when the operation count value reaches the first counting value reg1, the signal calculator 329 performs the operation again from step S1.

As described above, the touch sensing display device according to the present invention adjusts the timing of occurrence of the high period of the compensation Tx driving signal so as not to overlap with the high period of the display control signal, thereby avoiding noise introduced by the display control signals, thereby preventing touch sensitivity. Can improve.

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
22: data driving circuit 24: scan driving circuit
30: Tx driving circuit 31: Tx generating circuit
32: Tx compensating circuit 34: Rx driving circuit
36: touch controller 40: timing controller
321,323: Rising edge detector 322,324: Falling edge detector
325,326,327,328 Counter 329 Signal operator
329A: calculator 329B: Tx 'generator

Claims (6)

Display panel;
A touch screen coupled to the display panel and having a plurality of sensor nodes formed by intersection of a plurality of Tx lines and a plurality of Rx lines;
A Tx generator for generating an input Tx drive signal;
A Tx compensation circuit configured to shift the input Tx drive signal based on a display control signal applied from the outside to generate a compensation Tx drive signal and to supply the Tx lines to the Tx lines; And
An Rx driving circuit configured to receive and sample the voltages of the sensor nodes through the Rx lines, and to analog-digital convert the sampled sensor node voltages to generate touch raw data;
The high section of the compensation Tx driving signal and the high section of the display control signal are non-overlapping with each other,
The Tx compensation circuit,
A first counter that counts between neighboring rising edges of the display control signal to generate a first counting value corresponding to one period width of the display control signal;
A second counter counting between a neighboring rising edge and a falling edge of the display control signal to generate a second counting value corresponding to a high section width of the display control signal;
A third counter for counting between neighboring rising edges of the input Tx driving signal to generate a third counting value corresponding to one period width of the input Tx driving signal;
A fourth counter counting between a neighboring rising edge and a falling edge of the input Tx driving signal to generate a fourth counting value corresponding to a high section width of the input Tx driving signal; And
And a signal calculator configured to generate the compensation Tx driving signal non-overlapping with the high period of the display control signal based on the first to fourth counting values. The method of claim 1,
And the display control signal is a timing control signal generated at a predetermined cycle. The method of claim 1,
And the display control signal is selected from one of a horizontal synchronization signal and a data enable signal. The method of claim 1,
The Tx compensation circuit,
A first rising edge detector for detecting a rising edge of the display control signal;
A first falling edge detector detecting a falling edge of the display control signal;
A second rising edge detector for detecting a rising edge of the input Tx driving signal; And
And a second falling edge detector for detecting a falling edge of the input Tx driving signal. The method of claim 1,
The signal calculator,
First to fourth registers respectively storing the first to fourth counting values;
An operation unit configured to calculate a rising point and a falling point of the compensation Tx driving signal by embedding an operation counter that repeatedly counts the row periods of the display control signal; And
And a Tx 'generation unit configured to generate the compensation Tx driving signal non-overlapping with the high period of the display control signal based on the rising point and the falling point. The method of claim 1,
And at least one high section of the compensation Tx driving signal corresponds to a low section of each display control signal.

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