KR102404391B1 - Display Device Having The Touch Sensor - Google Patents

Abstract

A touch sensor-embedded display device according to the present invention includes a display panel, a power supply unit, and a driving signal output unit. The display panel includes a pixel array coupled to touch sensors. The power supply unit generates a pixel driving voltage and a touch driving voltage. The driving signal output unit receives the pixel driving voltage and the touch driving voltage, and provides the pixel driving voltage to the pixel array during the display driving period, and provides the touch driving voltage to the touch sensors during the touch sensing period. The driving signal output unit includes a touch buffer and a touch buffer control unit. The touch buffer is driven by receiving the power supply voltage, and outputs the touch driving voltage input to the first input terminal to the output terminal. The touch buffer control unit is connected to the power supply voltage supply terminal and the touch buffer, and is turned off by an enable signal input during the display driving period.

Description

Display Device Having The Touch Sensor

The present invention relates to a touch sensor embedded display device.

A user interface (UI) enables communication between a person (user) and various electrical and electronic devices, so that the user can easily control the device as he or she wants. Representative examples of the user interface include a keypad, a keyboard, a mouse, an on-screen display (OSD), and a remote controller having an infrared communication or radio frequency (RF) communication function. User interface technology is developing in the direction of increasing user sensitivity and ease of operation. Recently, a user interface is evolving into a touch UI, a voice recognition UI, a 3D UI, and the like.

Touch UI is essential for portable information devices such as smart phones, and is being applied to notebook computers, computer monitors, and home appliances. Recently, a technology for embedding touch sensors in a pixel array of a display panel (hereinafter, referred to as an “in-cell touch sensor”) has been proposed. The in-cell touch sensor technology can install touch sensors on the display panel without increasing the thickness of the display panel. These touch sensors are connected to pixels through parasitic capacitance and signal wires (hereinafter referred to as “pixel signal wires”). The driving method includes a period for driving the pixels (hereinafter referred to as a “display driving period”) and a period for driving the touch sensors (hereinafter referred to as “touch The sensing period") is time-divided.

During the display driving period, the pixels are supplied with a pixel driving voltage, and during the touch sensing period, the touch sensors are supplied with the touch driving voltage. That is, the pixel driving voltage is used only during the image display period, and the touch driving voltage is used only during the touch sensing period. However, the buffer for outputting the pixel driving voltage is driven even during the touch sensing period, and the buffer for outputting the touch driving voltage is driven even during the display driving period, so unnecessary current consumption is wasted.

An object of the present invention is to provide a display device with a built-in touch sensor capable of reducing current consumption.

In order to achieve the above object, a display device with a built-in touch sensor according to the present invention includes a display panel, a power supply unit, and a driving signal output unit. The display panel includes a pixel array coupled to touch sensors. The power supply unit generates a pixel driving voltage and a touch driving voltage. The driving signal output unit receives the pixel driving voltage and the touch driving voltage, and provides the pixel driving voltage to the pixel array during the display driving period, and provides the touch driving voltage to the touch sensors during the touch sensing period. The driving signal output unit includes a touch buffer and a touch buffer control unit. The touch buffer is driven by receiving the power supply voltage, and outputs the touch driving voltage input to the first input terminal to the output terminal. The touch buffer control unit is connected to the power supply voltage supply terminal and the touch buffer, and is turned off by an enable signal input during the display driving period.

The touch sensor-embedded display device according to the present invention stops the operation of the touch buffers outputting the touch driving signal during the display driving period and stops the operation of the buffers outputting the pixel driving voltage during the touch sensing period, thereby unnecessarily driving the buffer. This can be prevented to reduce current consumption.

1 is a view showing a touch sensor built-in display device according to the present invention.
FIG. 2 is a view showing a pixel array of the display panel shown in FIG. 1;
FIG. 3 is a diagram illustrating input and output of the touch driving unit shown in FIG. 1 ;
4 is a diagram illustrating a configuration of a touch driving unit;
5 is a diagram illustrating a common voltage output buffer;
6 is a diagram illustrating an enable signal generator;
7 and 8 are views showing a driving voltage output unit according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of the present invention will be described. Like reference numerals refer to substantially identical elements throughout. In the following description, if it is determined that a detailed description of a known technology or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, the component names used in the following description may be selected in consideration of ease of writing the specification, and may be different from the component names of the actual product.

1 is a view showing a display device with a built-in touch sensor according to the present invention. 2 is a diagram illustrating pixels included in a touch sensor, and FIG. 3 is a diagram illustrating a touch driver. In FIGS. 1 and 2 , each of the touch sensors and the sensing lines are individually denoted by reference numerals, but in the detailed description, they are referred to as a touch sensor (TC) and a sensing line (TW) when collectively referred to as a position of each component in the detailed description. to explain

1 to 3 , the touch sensor embedded display device according to the present invention includes a display panel 100 , a host system 105 , a timing controller 110 , a data driver 120 , a gate driver 130 , and a touch screen. It includes a driving unit 400 .

In the display panel 100 , pixels P and touch sensors TC are disposed. The display panel 100 includes an upper substrate and a lower substrate facing each other with a liquid crystal layer LC interposed therebetween. The pixel array of the display panel 100 includes data lines DL, gate lines GL, thin film transistors TFT formed at intersections of data lines DL and gate lines GL, thin film transistors ( a pixel electrode 5 connected to the TFT), and a storage capacitor (Cst) connected to the pixel electrode 5 . The thin film transistor TFT is turned on in response to a gate pulse from the gate line GL to supply a data voltage applied through the data line DL to the pixel electrode 5 . The liquid crystal layer LC is driven by a voltage difference between the data voltage charged in the pixel electrode 5 and the common voltage Vcom applied to the touch common electrode VEL, thereby controlling the amount of light transmitted.

The touch sensor TC is connected to a plurality of pixels and is implemented as a capacitance type to sense a touch input. A plurality of pixels P are coupled to each touch sensor TC. FIG. 2 illustrates a case in which nine pixels P arranged in a 3x3 matrix manner are allocated to one touch sensor TC.

The common electrode VEL is divided into units of the touch sensor TC, and the area occupied by the common electrode VEL may be referred to as the touch sensor TC. Each of the touch sensors TC is connected by being assigned one sensing line TW. For example, the sensing line (TW[1,1]) of row 1, column 1 is connected to the touch sensor (TC[1,1]) of row 1, column 1, and the touch sensor of row 1, column 2 (TC[1,2]) ) is connected to the sensing lines TW[1,2] in row 1 and column 2.

As shown in FIG. 3 , the common electrode VEL receives the common voltage Vcom, which is the reference voltage of the pixels during the display driving period Td, and supplies the first touch driving signal Tdrv1 during the touch sensing period Tt. receive The first touch driving signal Tdrv1 swings between the first high voltage VCOM_H and the first low voltage VCOM_L.

The gate line GL receives the gate low voltage VGL during the display driving period Td and receives the second touch driving signal Tdrv2 during the touch sensing period Tt. The second touch driving signal Tdrv2 swings between the second high voltage VGL_H and the second low voltage VGL_L.

The timing controller 110 inputs timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE, and a main clock MCLK input from the host system 105 . The operation timings of the data driver included in the SRIC and the gate driver 130 are synchronized. The gate timing control signal includes a gate start pulse (GSP), a gate shift clock (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) and a source output enable signal (SOE).

The host system 105 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 105 includes a system on chip (SoC) having a built-in scaler and converts digital video data RGB of an input image into a format suitable for display on the display panel DIS. The host system 105 transmits the timing signals Vsync, Hsync, DE, and MCLK together with digital video data to the timing controller 110 . In addition, the host system 105 executes an application program associated with the coordinate information Txy of the touch data input from the touch driving circuit 400 .

The data driver 120 receives image data from the timing controller, converts it into positive/negative gamma compensation voltages, and outputs positive/negative data voltages. The data voltage is supplied to the data lines DL.

The gate driver 130 sequentially supplies gate pulses to the gate lines GL under the control of the timing controller. The gate pulse output from the gate driver is synchronized with the data voltage. The gate driver may be formed on the lower substrate of the display panel 100 together with the pixel array through a gate in panel (GIP) process.

4 is a diagram illustrating a configuration of a touch driving unit.

Referring to FIG. 4 , the touch driving unit 400 includes an MCU 430 , a power supply unit 410 , and a TPIC 420 .

The power supply unit 410 generates a power voltage VDD, a common voltage Vcom, and a second low voltage VGL_L, and provides the generated voltages to the TPIC 420 . The power supply voltage VDD is a voltage for driving various buffers of the TPIC 420 . The common voltage Vcom is a voltage applied to the common electrode VEL during the display driving period Td. The gate low voltage VGL is a low level voltage of the gate pulse.

The power supply unit 410 outputs the common voltage Vcom using the common voltage output buffer VCOM_BUF shown in FIG. 5 . The common voltage output buffer VCOM_BUF operates using the power supply voltage VDD. The common voltage output control unit Tvcom determines a section to which the power supply voltage VDD is supplied. The common voltage output controller Tvcom is turned on when the touch synchronization signal Tsync is at a high level, and supplies the power voltage VDD to the common voltage output buffer VCOM_BUF. As a result, the common voltage output buffer VCOM_BUF is driven by receiving the power supply voltage VDD only during the display driving period Td. That is, since the common voltage output buffer VCOM_BUF does not operate during the touch sensing period Tt in which the common voltage Vcom is not required, unnecessary power consumption may be improved.

The MCU 430 transfers the touch synchronization signal Tsync and the pulse width control signal PWM_tx provided from the timing controller 110 to the TPIC 420 . The MCU 430 compares touch data input from the ROIC (not shown) with a predetermined threshold, and determines touch raw data equal to or greater than the threshold 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 equal to or greater than a threshold value and calculates the coordinates of each of the touch input positions. The MCU 430 transmits an identification code of each of the touch input data and the touch coordinate information Txy to the host system 105 .

The ROIC (not shown) stores the touch raw data Tdata obtained by driving the touch sensor TC in the buffer memory, and provides the touch raw data Tdata stored in the buffer memory to the MCU 430 at regular intervals.

The TPIC 420 generates a first high voltage VCOM_H, a first low voltage VCOM_L, a second high voltage VGL_H, and a second low voltage VGL_L by using the voltages provided from the power supply unit 410 . do. The first high voltage VCOM_H and the first low voltage VCOM_L are the high level voltage and the low level voltage of the first touch driving signal Tdrv1, respectively. The second high voltage VGL_H and the second low voltage VGL_L are the high level voltage and the low level voltage of the second touch driving signal Tdrv2, respectively. The TPIC 420 generates a first touch driving signal Tdrv1 using a first high voltage VCOM_H and a first low voltage VCOM_L, and a second high voltage VGL_H and a second low voltage VGL_L. to generate the second touch driving signal Tdrv2. To this end, the TPIC 420 includes an enable signal generating unit 421 , a first driving signal output unit 423 generating a first touch driving signal Tdrv1 , and a first driving signal generating unit generating a second touch driving signal Tdrv2 . 2 includes a driving signal output unit 425 .

As shown in FIG. 6 , the enable signal generator 421 receives the touch synchronization signal Tsync and generates the enable signal EN. The enable signal generator 421 inverts the voltage level of the touch synchronization signal Tsync using the first inverter INV1 to generate the enable signal EN. In addition, the enable signal generator 421 may use a signal passing through the first and second inverters INV1 and INV2 as the enable signal EN.

The first driving signal output unit 423 outputs the first touch driving signal Tdrv1 during the touch sensing period Tt and the common voltage Vcom during the display driving period Td. The second driving signal output unit 425 outputs the second touch driving signal Tdrv2 during the touch sensing period Tt and outputs the gate low voltage VGL during the display driving period Td.

7 is a view showing a first driving signal output unit according to the first embodiment, and FIG. 8 is a view showing a second driving signal output unit according to the first embodiment.

Referring to FIG. 7 , the first driving signal output unit 423 includes first touch buffers HB1 and LB1 , first touch buffer controllers SW1 and SW2 , and a first multiplexer MUX1 .

The first high buffer HB1 is driven by receiving the power voltage VDD from the power supply unit 410 through the power voltage input terminal In1 . The first high buffer HB1 receives the first high voltage VCOM_H through the first input terminal (+), and receives the feedback voltage of the output terminal Nout1 through the second input terminal (-).

The first buffer control unit SW1 controls the timing at which the power voltage VDD is applied to the first high buffer HB1 to determine the operation period of the first high buffer HB1 . That is, the first buffer control unit SW1 is turned on by the enable signal EN and outputs the first high voltage VCOM_H during the touch sensing period Tt. In addition, the first buffer control unit SW1 blocks the supply of the power voltage VDD to the first high buffer HB1 during the display driving period Td in which the enable signal EN is not input, so that the first high buffer Controls (HB1) not to operate.

The first low buffer LB1 is driven by receiving the power voltage VDD from the power supply unit 410 through the power voltage input terminal In2 . The first low buffer LB1 receives the first low voltage VCOM_L through the first input terminal (+), and receives the feedback voltage of the output terminal Nout2 through the second input terminal (-).

The second buffer control unit SW2 controls the timing at which the power voltage VDD is applied to the first low buffer LB1 to determine the operation period of the first low buffer LB1 . That is, the second buffer control unit SW2 is turned on by the enable signal EN and outputs the first low voltage VCOM_L during the touch sensing period Tt. In addition, the second buffer control unit SW2 blocks the supply of the power voltage VDD to the first low buffer LB1 during the display driving period Td in which the enable signal EN is not input to the first low buffer Controls (LB1) not to operate.

The first multiplexer MUX1 includes first to third switches M1 to M3.

The first switch M1 is positioned between the output terminal Nout1 of the first high buffer HB1 and the first mux output terminal Mout1. The first switch M1 outputs the first high voltage output from the first high buffer HB1 to the first mux output terminal Mout1 in response to the high level voltage of the pulse width control signal PWM_tx.

The second switch M2 is positioned between the output terminal Nout2 of the first low buffer LB1 and the first mux output terminal Mout1. The second switch M2 outputs the first low voltage output from the first low buffer LB1 to the first mux output terminal Mout1 in response to the low level voltage of the pulse width control signal PWM_tx.

As a result, during the touch sensing period Tt, the first mux output terminal Mout1 receives the first touch driving signal Tdrv1 in the form of an AC signal swinging between the first high voltage VCOM_H and the first low voltage VCOM_L. print out

The third switch M3 is positioned between the common voltage output terminal VCOM_out and the first mux output terminal Mout1. The third switch M3 outputs a common voltage to the first mux output terminal Mout1 in response to the low level voltage of the touch synchronization signal Tsync.

Referring to FIG. 8 , the second driving signal output unit 425 according to the first embodiment includes the second touch buffers HB2 and LB2, the second touch buffer controllers SW3 and SW4, and the second multiplexer MUX2. include

The second high buffer HB2 is driven by receiving the power voltage VDD from the power supply unit 410 through the power voltage input terminal In3 . The second high buffer HB2 receives the first high voltage through the first input terminal (+), and receives the feedback voltage of the output terminal Nout3 through the second input terminal (-).

The third buffer controller SW3 controls the timing at which the power voltage VDD is applied to the second high buffer HB2 to determine the operation period of the second high buffer HB2 . That is, the third buffer controller SW3 is turned on by the enable signal EN and outputs the second high voltage VGL_H during the touch sensing period Tt. In addition, the third buffer control unit SW3 blocks the supply of the power voltage VDD to the second high buffer HB2 during the display driving period Td in which the enable signal EN is not input to the second high buffer Controls (HB2) not to operate.

The second low buffer LB2 is driven by receiving the power voltage VDD from the power supply unit 410 through the power voltage input terminal In4 . The second low buffer LB2 receives the second low voltage input through the first input terminal (+), and receives the feedback voltage of the output terminal Nout4 through the second input terminal (−).

The fourth buffer control unit SW4 controls the timing at which the power voltage VDD is applied to the second low buffer LB2 to determine the operation period of the second low buffer LB2 . That is, the fourth buffer control unit SW4 is turned on by the enable signal EN and outputs the second low voltage VGL_L during the touch sensing period Tt. In addition, the fourth buffer control unit SW4 blocks the supply of the power voltage VDD to the second low buffer LB2 during the display driving period Td in which the enable signal EN is not input to the second low buffer Controls (LB2) not to operate.

The second multiplexer MUX2 includes fourth to sixth switches M54 to M66.

The fourth switch M44 is positioned between the output terminal Nout4 of the second high buffer HB2 and the second mux output terminal Mout2. The fourth switch M4 outputs the second high voltage output from the second high buffer HB2 to the second mux output terminal Mout2 in response to the high level voltage of the pulse width control signal PWM_tx.

The fifth switch M5 is positioned between the output terminal Nout4 of the second low buffer LB2 and the second mux output terminal Mout2. The fifth switch M5 outputs the second low voltage VGL_L output from the second low buffer LB2 to the second mux output terminal Mout2 in response to the low level voltage of the pulse width control signal PWM_tx. .

As a result, during the touch sensing period Tt, the second mux output terminal Mout2 receives the second touch driving signal Tdrv2 in the form of an AC signal swinging between the second high voltage VGL_H and the second low voltage VGL_L. print out

The sixth switch M6 is positioned between the gate low voltage output terminal VGL_OUT of the power supply unit 410 and the second mux output terminal Mout2. The sixth switch M6 outputs the gate low voltage VGL to the second mux output terminal Mout2 in response to the low level voltage of the touch synchronization signal Tsync.

As described above, since the TPIC 420 of the present invention cuts off the power voltage VDD supplied to the touch buffers HP1, LB1, HP2, LB2 during the display driving period Td, during the display driving period Td The touch buffers HP1, LB1, HP2, and LB2 do not operate.

Conventionally, even during the display driving period Td in which the outputs of the touch buffers HP1 , LB1 , HP2 , and LB2 are not applied to the display panel 100 , the touch buffers HP1 , LB1 , HP2 , LB2 are supplied with the power supply voltage VDD. was input and operated. Accordingly, current consumption was wasted due to unnecessary driving of the touch buffers HP1, LB1, HP2, and LB2.

In contrast, in the present invention, the operation of the touch buffers HP1, LB1, HP2, LB2 during the display driving period Td in which the output of the touch buffers HP1, LB1, HP2, LB2 is blocked by the multiplexers MUX1 and MUX2 , it is possible to reduce the current consumed by the touch buffers HP1, LB1, HP2, and LB2 during the display driving period Td.

In the first embodiment, the first to fourth buffer controllers SW1 to SW4 are implemented as n-type transistors and are turned on by the high-level voltage of the enable signal EN. The first to fourth buffer controllers SW1 and SW4 may be implemented as p-type transistors to be operated by receiving the touch synchronization signal Tsync as an occupational input.

Those skilled in the art from the above description will be able to see that various changes and modifications can be made without departing from the technical spirit of the present invention. Accordingly, the present invention should not be limited to the contents described in the detailed description, but should be defined by the claims.

5: Pixel electrode 7: Common electrode
TC: Touch sensor TW: Sensing line
105: host 110: timing controller
120: data driver 130: gate driver
400: touch driver 410: power supply
420: TPIC 421: enable signal generator
423: first driving signal generating unit 425: second driving signal generating unit

Claims (10)

a display panel including a pixel array coupled to touch sensors;
a power supply for generating a pixel driving voltage and a touch driving voltage; and
a driving signal output unit receiving the pixel driving voltage and the touch driving voltage, providing the pixel driving voltage to the pixel array during a display driving period, and providing the touch driving voltage to the touch sensors during a touch sensing period; ,
The driving signal output unit
a touch buffer driven by receiving a power supply voltage and outputting the touch driving voltage input to a first input terminal to an output terminal;
a touch buffer control unit connected to a power supply voltage supply terminal and the touch buffer and turned off by an enable signal input during the display driving period;
the touch buffer control unit is connected between the power supply voltage input terminal of the touch buffer and the output terminal of the touch buffer, and is turned off by the enable signal to float the output terminal of the touch buffer;
Display with built-in touch sensor. The method of claim 1,
The pixel driving voltage includes a common voltage, and the touch driving voltage includes a first high voltage and a first low voltage,
The driving signal output unit
providing the common voltage to the touch sensor during the display driving period;
A touch sensor-embedded display device that provides a first touch driving signal swinging between the first high voltage and the first low voltage to the touch sensor during the touch sensing period. 3. The method of claim 2,
the touch buffer
a first high buffer driven using the power supply voltage and configured to output a first high voltage input to a first input terminal through a first output terminal; and
a first low buffer driven using the power supply voltage and outputting a first low voltage input to a first input terminal through a second output terminal;
The driving signal output unit
Receives a pulse width control signal swinging between a high level voltage and a low level voltage,
a first mux switch connecting a first output terminal of the first high buffer and a first mux output terminal and outputting the first high voltage to the first mux output terminal in response to the high level voltage of the pulse width control signal; and
a second mux switch connecting a second output terminal of the first low buffer and a first mux output terminal and outputting the first low voltage to the first mux output terminal in response to the low level voltage of the pulse width control signal; A touch sensor built-in display. 4. The method of claim 3,
The driving signal output unit
receiving a touch synchronization signal that maintains a high level voltage during the display driving period and maintains a low level voltage during the touch sensing period;
A third mux switch connected to the common voltage output terminal and the first mux output terminal of the power supply unit and configured to output the common voltage from the common voltage output terminal through the first mux output terminal in response to the high level voltage of the touch synchronization signal A touch sensor built-in display device further comprising a. 4. The method of claim 3,
The touch buffer controller
a first buffer control unit connected to the power supply voltage supply terminal and the first high buffer and turned on by the enable signal; and
and a second buffer controller connected to the power supply voltage supply terminal and the first low buffer and turned on by the enable signal. 3. The method of claim 2,
The power supply unit
a common voltage output buffer for outputting the common voltage; and
and a common voltage output buffer controller connected to a power supply voltage input terminal and a power supply voltage input terminal of the common voltage output buffer and turned on in response to a touch synchronization signal input during the touch sensing period. The method of claim 1,
The pixel driving voltage includes a gate low voltage, and the touch driving voltage includes a second high voltage and a second low voltage,
The driving signal output unit
providing the gate-low voltage to a gate line disposed in the pixel array during the display driving period;
and a second touch driving signal swinging between the second high voltage and the second low voltage to the gate line during the touch sensing period. 8. The method of claim 7,
the touch buffer
a second high buffer driven using the power supply voltage and configured to output a second high voltage input to a first input terminal through a third output terminal; and
a second low buffer driven using the power supply voltage and outputting a second low voltage input to a first input terminal through a fourth output terminal;
The driving signal output unit
Receives a pulse width control signal swinging between a high level voltage and a low level voltage,
a fourth mux switch connecting a third output terminal of the second high buffer and a second mux output terminal and outputting the second high voltage to the second mux output terminal in response to the high level voltage of the pulse width control signal; and
a fifth mux switch connecting the fourth output terminal of the second low buffer and the second mux output terminal and outputting the second low voltage to the second mux output terminal in response to the low level voltage of the pulse width control signal; Including touch sensor embedded display. 9. The method of claim 8,
The driving signal output unit
receiving a touch synchronization signal that maintains a high level voltage during the display driving period and maintains a low level voltage during the touch sensing period;
a second mux output terminal connected to the gate low voltage output terminal and the second mux output terminal of the power supply and outputting the gate low voltage from the gate low voltage output terminal through the second mux output terminal in response to the high level voltage of the touch synchronization signal 6 A display device with a built-in touch sensor that further includes a mux switch. delete

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