TWI847192B - Touch display device and driving method thereof - Google Patents

Abstract

A touch display device and driving method thereof are provided. The touch display device includes a display panel, a touch element array and a conductor film layer. The touch element array is configured to perform a touch detection action. The conductor film layer is arranged on the touch element array and the display panel. During at least one display period, the conductor film layer receives a first reference voltage, and during at least one touch period of non-display period, the conductor film layer is in a floating state.

Description

Touch display device and driving method thereof

The present invention relates to a display device, and in particular to a touch display device and a driving method thereof.

In conventional touch display devices, electrostatic discharge (ESD) testing is usually performed on related circuits. However, under the circuit architecture of conventional touch display devices, the ESD current generated by the ESD test is often unable to be effectively discharged, thereby affecting the quality of the display screen.

Therefore, how to effectively enhance the ESD current discharge capability of touch display devices to improve the quality of display images will be an important topic for relevant technical personnel in this field.

The present invention provides a touch display device and a driving method thereof, which can effectively enhance the ability to discharge ESD current, thereby improving the quality of the display screen.

The touch display device of the present invention comprises a display panel, a touch element array and a conductive film layer. The touch element array is used to perform a touch detection action. The conductive film layer is arranged on the touch element array and the display panel. During at least one display period, the conductive film layer receives a first reference voltage, and during at least one touch period of the non-display period, the conductive film layer is in a floating state.

The driving method of the touch display device of the present invention includes: providing a display panel; providing a touch element array and a conductive film layer, so that the touch element array performs a touch detection action, wherein the conductive film layer is arranged on the touch element array and the display panel; in at least one display period, the conductive film layer receives a first reference voltage; in at least one touch period of the non-display period, the conductive film layer is in a floating state.

Based on the above, the touch display device and the driving method thereof described in the embodiments of the present invention can switch the timing through the controller, so that the electrostatic discharge current generated by the conductive film layer under the ESD test can be discharged to the reference ground terminal through the leakage path during the display stage, thereby enhancing the electrostatic dissipation capability and improving the quality of the display screen.

The term "coupled (or connected)" used throughout the specification of this case (including the scope of the patent application) may refer to any direct or indirect means of connection. For example, if the text describes a first device coupled (or connected) to a second device, it should be interpreted that the first device can be directly connected to the second device, or the first device can be indirectly connected to the second device through other devices or some connection means. In addition, wherever possible, elements/components/steps with the same number in the drawings and embodiments represent the same or similar parts. Elements/components/steps with the same number or the same terminology in different embodiments can refer to each other's related descriptions.

Please refer to FIG1 , which is a schematic diagram of a touch display device according to an embodiment of the present invention. The touch display device 100 includes a display panel 110 , a touch element array 120 , and a conductive film layer 130 . The touch element array 120 may be embedded in the display panel 110 .

In this embodiment, the touch element array 120 may include a plurality of touch elements TP and a plurality of touch electrode layers TEL. These touch electrode layers TEL may utilize self-capacitance, mutual capacitance or other various sensing methods to enable these touch elements TP to complete touch sensing operations. For example, when a user touches or presses the display panel 110 through a touch medium (such as a finger), the touch element array 120 may perform a touch detection action through these touch elements TP and these touch electrode layers TEL.

It is worth mentioning that, under some design requirements (in some embodiments), the touch display device 100 may be provided with a color filter on the display panel 110, and the conductive film layer 130 may be provided on the color filter. Under other design requirements (in other embodiments), the touch display device 100 may be provided with a cover glass on the display panel 110, and the conductive film layer 130 may be provided on the cover glass. In addition, under other design requirements (in other embodiments), the touch display device 100 may also be provided with an optical film on the display panel 110, and the conductive film layer 130 may be provided on the optical film. Thereby, when performing an ESD test, the touch display device 100 can perform a test operation on the conductive film layer 130.

For example, in the present embodiment, the conductive film layer 130 may be, for example, indium tin oxide (ITO), indium doped zinc oxide (IZO), indium tin zinc oxide (ITZO), polydiethylene dioxythiophene (PEDOT), carbon nanotube (CNT), and metal materials (such as aluminum (Al), molybdenum (Mo), and copper (Cu)), but the present invention is not particularly limited.

In this regard, please refer to FIG. 1 and FIG. 2A to FIG. 2B simultaneously. FIG. 2A and FIG. 2B are schematic diagrams showing the conductive film layer of FIG. 1 being disposed on the display panel. In this embodiment, the display panel 110 has a plurality of sub-pixels R, G and B with different display wavelengths (for example, sub-pixels that display the three primary colors of red, green and blue, respectively).

Specifically, the conductive film layer 130 may be partially disposed on the display panel 110. For example, in this embodiment, the overlapping area of the conductive film layer 130 disposed on the display panel 110 may be less than half of the area of the plurality of sub-pixels R, G, and B of the display panel 110. Furthermore, the conductive film layer 130 disposed (or overlapped) on the display panel 110 may be any pattern (e.g., a rectangle as shown in FIG. 2A or a circle as shown in FIG. 2B), but the present invention is not particularly limited thereto.

In other words, since the conductive film layer 130 is only partially disposed on the display panel 110, it means that part of the touch elements TP and the touch electrode layer TEL are not disposed by (or overlapped with) the conductive film layer 130. Therefore, when the touch display device 100 is subjected to an ESD test, the touch display device 100 can prevent the touch elements TP and the touch electrode layer TEL in the touch element array 120 from being shielded by the conductive film layer 130.

Regarding the operation of the touch display device 100, in this embodiment, when the touch display device 100 operates in a touch period of a frame cycle, the touch display device 100 can make the touch element TP and the touch electrode layer TEL in the touch element array 120 perform a touch detection action, and make the conductive film layer 130 in a floating state. Then, when the touch display device 100 operates in a display period of the frame cycle, the touch display device 100 can make the display panel 110 display a picture, and make the conductive film layer 130 receive the first reference voltage VGND through the leakage path CTL.

In this way, the touch display device 100 can discharge the electrostatic discharge current IESD to the reference ground terminal through the leakage path CTL during the display period, thereby enhancing the electrostatic dissipation capability and improving the quality of the display image.

FIG3 is a schematic diagram of a touch display device according to another embodiment of the present invention. Referring to FIG3 , the touch display device 300 includes a display panel 310, a clock generator 311, a controller 312, a touch element array 320, a conductive film layer 330, a circuit board 340, a switch T1, and a diode D1. The display panel 310, the touch element array 320, and the conductive film layer 330 shown in FIG3 can be deduced by referring to the relevant description of the display panel 110, the touch element array 120, and the conductive film layer 130 mentioned in FIG1 and FIG2A to FIG2B, so it is not repeated.

In the embodiment shown in FIG. 3 , a clock generator 311 may be disposed in a display panel 310 . The clock generator 311 may generate a clock signal CLK according to a preset timing state. A controller 312 is coupled to a plurality of touch elements TP in a touch element array 320 and the clock generator 311 . A switch T1 is coupled to the controller 312 and a conductive film layer 330 .

The controller 312 may generate a driving signal DS1 to the switch T1 according to the clock signal CLK, and the controller 312 may generate a pulse signal PS to the plurality of touch elements TP in the touch element array 320 according to the clock signal CLK.

In this embodiment, the controller 312 can be, for example, a central processing unit (CPU), a microprocessor, or other programmable processing unit (Microprocessor), a digital signal processor (Digital Signal Processor, DSP), a programmable controller, an application specific integrated circuit (Application Specific Integrated Circuits, ASIC), a programmable logic device (Programmable Logic Device, PLD) or other similar devices.

The circuit board 340 includes a diode D1. The anode terminal of the diode D1 is coupled to the first reference voltage VGND, and the cathode terminal of the diode D1 is coupled to the switch T1. In the present embodiment, the circuit board 340 may be, for example, a printed circuit board or a flexible circuit board, but the present invention is not particularly limited thereto. The circuit board 340 may provide a power supply voltage VDD to the clock generator 311 and the controller 312 as an operating voltage of the clock generator 311 and the controller 312.

For implementation details of the touch display device 300, please refer to FIG. 3 and FIG. 4, FIG. 4 is a timing diagram of the touch display device according to FIG. 3. In this embodiment, the clock generator 311 can divide a frame period FP of the touch display device 300 into a plurality of touch periods TD11-TD1N and a plurality of display periods TD21-TD2N according to a preset timing state, and correspondingly generate a clock signal CLK to the controller 312. Among them, these touch periods TD11-TD1N and these display periods TD21-TD2N occur alternately in the frame period FP.

Specifically, when the touch display device 300 operates in the touch period TD11, the controller 312 can generate a driving signal DS1 having a gate low voltage VGL to the switch T1 according to the clock signal CLK, so that the switch T1 is in an off state. In this case, the conductive film layer 330 can be in a floating state (for example, a voltage VFloating) during the touch period TD11.

On the other hand, the controller 312 can generate a pulse signal PS having a pulse height between the second reference voltage VCOM and the preset voltage VTX (e.g., 0V to 4V) to the touch element array 320 according to the clock signal CLK to activate a plurality of touch elements TP in the touch element array 320. Furthermore, these touch elements TP can perform a touch detection action during the touch period TD11.

Next, when the touch display device 300 operates in the display period TD21 after the touch period TD11, the controller 312 can generate a driving signal DS1 having a gate high voltage VGH to the switch T1 according to the clock signal CLK, so that the switch T1 is in a conducting state. In this case, the touch display device 300 can discharge the electrostatic discharge current IESD to the reference ground terminal of the circuit board 340 through the leakage path CTL1, and the conductive film layer 330 can receive the first reference voltage VGND during the display period TD21.

On the other hand, the controller 312 can maintain the pulse signal PS at the voltage level of the second reference voltage VCOM according to the clock signal CLK, so that the display panel 310 can display images according to the pulse signal PS.

It is worth mentioning that the operation details of the touch display device 300 in the remaining touch periods TD12 to TD1N and the display period TD2N can be deduced by referring to the relevant descriptions of the operation in the touch period TD11 and the display period TD21, and thus will not be elaborated again.

Fig. 5 is a schematic diagram of a touch display device according to another embodiment of the present invention. Referring to Fig. 5 , the touch display device 500 includes a display panel 510, a clock generator 541, a controller 512, a touch element array 520, a conductive film layer 530, a circuit board 540, a switch T1, and a diode D1. The display panel 510, clock generator 541, controller 512, touch element array 520, conductive film layer 530, circuit board 540, switch T1 and diode D1 shown in FIG5 can be inferred by referring to the relevant descriptions of the display panel 310, clock generator 311, controller 312, touch element array 320, conductive film layer 330, circuit board 340, switch T1 and diode D1 mentioned in FIGS. 2A to 2B and FIG3 , and thus will not be elaborated again.

Different from the embodiment of FIG. 3 , in this embodiment, the clock generator 541 may be disposed in the circuit board 540 . The implementation details of the touch display device 500 operating in a plurality of touch periods TD11 to TD1N and a plurality of display periods TD21 to TD2N may be deduced from the relevant descriptions of FIG. 1 , FIG. 2A to FIG. 2B , FIG. 3 and FIG. 4 , and thus will not be described in detail.

Fig. 6 is a schematic diagram of a touch display device according to another embodiment of the present invention. Referring to Fig. 6, the touch display device 600 includes a display panel 610, a clock generator 611, a controller 612, a touch element array 620, a conductive film layer 630, a circuit board 640, a switch T1, a switch T2, and a diode D1. The display panel 610, clock generator 611, controller 612, touch element array 620, conductive film layer 630, circuit board 640, switch T1 and diode D1 shown in FIG. 6 can be inferred by referring to the relevant descriptions of the display panel 310, clock generator 311, controller 312, touch element array 320, conductive film layer 330, circuit board 340, switch T1 and diode D1 mentioned in FIGS. 2A to 2B and FIG. 3 , and thus will not be elaborated again.

Different from the embodiment of FIG. 3 , in this embodiment, the display panel 610 further includes a switch T2. The switch T2 is coupled to the controller 612 and the conductive film layer 630. The switches T1 and T2 of this embodiment can be implemented by NMOS transistors, for example, but the present invention is not particularly limited thereto.

For details of the implementation of the touch display device 600, please refer to FIG. 4 and FIG. 6. In this embodiment, when the touch display device 600 operates in the touch period TD11, the controller 612 can generate drive signals DS1 and DS2 with a gate low voltage VGL to switches T1 and T2 respectively according to the clock signal CLK, so that switches T1 and T2 are in an open state. In this case, the conductive film layer 330 can be in a floating state (for example, a voltage VFloating) during the touch period TD11.

On the other hand, the controller 612 can generate a pulse signal PS having a pulse height between the second reference voltage VCOM and the preset voltage VTX (e.g., 0V to 4V) to the touch element array 620 according to the clock signal CLK to activate a plurality of touch elements TP in the touch element array 620. Furthermore, these touch elements TP can perform a touch detection action during the touch period TD11.

Next, when the touch display device 600 operates in the display period TD21 after the touch period TD11, the controller 612 can generate a driving signal DS1 having a gate high voltage VGH to the switch T1 according to the clock signal CLK, so that the switch T1 is in a conducting state. In this case, the touch display device 600 can discharge the electrostatic discharge current IESD to the reference ground terminal of the circuit board 640 through the leakage path CTL1, and the conductive film layer 630 can receive the first reference voltage VGND during the display period TD21.

In addition, during the display period TD21, the controller 612 can generate a driving signal DS2 having a gate high voltage VGH to the switch T2 according to the clock signal CLK, so that the switch T2 is in a conducting state. In this case, the controller 612 can provide a ground signal DSD to the conductive film layer 630 through the leakage path CTL2 to further enhance the discharge capability of the touch display device 600 for the electrostatic discharge current IESD.

On the other hand, the controller 612 can maintain the pulse signal PS at the voltage level of the second reference voltage VCOM according to the clock signal CLK, so that the display panel 610 can display images according to the pulse signal PS.

It is worth mentioning that the operation details of the touch display device 600 in the remaining touch periods TD12 to TD1N and the display period TD2N can be deduced by referring to the relevant descriptions of the operation in the touch period TD11 and the display period TD21, and thus will not be elaborated again.

According to the description of the above embodiments, the controller of the touch display device can switch the timing so that the electrostatic discharge current IESD generated by the conductive film layer under the ESD test can be discharged to the reference ground through the leakage path during the display phase, thereby enhancing the electrostatic dissipation capability and improving the quality of the display image.

FIG7 is a flow chart of a method for driving a touch display device according to an embodiment of the present invention. Please refer to FIG1 and FIG7 simultaneously. In step S710, the touch display device may provide a display panel. In step S720, the touch display device may provide a touch element array and a conductive film layer, so that the touch element array performs a touch detection operation, wherein the conductive film layer is disposed on the touch element array and the display panel.

In step S730, the touch display device can make the conductive film layer receive the first reference voltage during at least one display period. In step S740, the touch display device can make the conductive film layer in a floating state during at least one touch period of the non-display period.

The implementation details of each step are fully described in the aforementioned embodiments and implementation methods, and will not be elaborated here.

In summary, the touch display device and the driving method thereof described in the embodiments of the present invention can switch the timing through the controller, so that the electrostatic discharge current generated by the conductive film layer under the ESD test can be discharged to the reference ground terminal through the leakage path during the display stage, thereby enhancing the electrostatic dissipation capability and improving the quality of the display image.

100, 300, 500, 600: touch display device 110, 310, 510, 610: display panel 120, 320, 520, 620: touch element array 130, 330, 530, 630: conductor film layer 311, 541, 611: clock generator 312, 512, 612: controller 340, 540, 640: circuit board CTL, CTL1, CTL2: leakage path CLK: clock signal D1: diode DS1, DS2: drive signal DSD: ground signal FP: frame period IESD: electrostatic discharge current PS: pulse signal R, G, B: sub-pixels S710~S740: steps T1, T2: switches TP: touch components TD11~TD1N: touch period TD21~TD2N: display period TEL: touch electrode layer VGND: first reference voltage VCOM: second reference voltage VDD: power supply voltage VFloating: voltage VTX: default voltage

FIG. 1 is a schematic diagram of a touch display device according to an embodiment of the present invention. FIG. 2A and FIG. 2B are schematic diagrams of a conductive film layer arranged on a display panel according to FIG. 1 . FIG. 3 is a schematic diagram of a touch display device according to another embodiment of the present invention. FIG. 4 is a timing diagram of a touch display device according to FIG. 3 . FIG. 5 is a schematic diagram of a touch display device according to another embodiment of the present invention. FIG. 6 is a schematic diagram of a touch display device according to another embodiment of the present invention. FIG. 7 is a flow chart of a method for driving a touch display device according to an embodiment of the present invention.

100: Touch display device

110: Display panel

120: Touch component array

130: Conductive film layer

CTL: leakage path

IESD: Electrostatic Discharge Current

TP: Touch panel

TEL: Touch electrode layer

VGND: First reference voltage

Claims (20)

A touch display device includes: a display panel; a touch element array for performing a touch detection action; and a conductive film layer disposed on the touch element array and the display panel, wherein during at least one display period, the conductive film layer receives a first reference voltage, and during at least one touch period other than the display period, the conductive film layer is in a floating state, wherein the touch element array is embedded in the display panel, and the conductive film layer is disposed on the touch element array and the display panel. A touch display device as described in claim 1, wherein the at least one display period and the at least one touch period occur alternately in a frame cycle. A touch display device as described in claim 1, wherein the conductive film layer is partially disposed on the display panel, and an overlapping area of the conductive film layer disposed on the display panel is less than half of the area of the plurality of sub-pixels of the display panel. The touch display device as described in claim 1 further includes: a first switch coupled to the conductive film layer; a clock generator for generating a clock signal; a controller coupled to the clock generator, the first switch and the touch element array for generating a drive signal to the first switch according to the clock signal; and a circuit board having a diode, wherein the anode end of the diode is coupled to the first reference voltage, and the cathode end of the diode is coupled to the first switch. A touch display device as described in claim 4, wherein during the at least one touch period, the controller generates the drive signal having a low gate voltage to the first switch according to the clock signal, and during the at least one display period, the controller generates the drive signal having a high gate voltage to the first switch according to the clock signal. A touch display device as described in claim 4, wherein during the at least one touch period, the controller generates a pulse signal having a pulse height between a second reference voltage and a preset voltage to the touch element array according to the clock signal, and during the at least one display period, the controller maintains the pulse signal at a voltage level of the second reference voltage. The touch display device as described in claim 4 further includes: a second switch coupled to the controller and the conductive film layer, wherein during the at least one touch period, the second switch is disconnected according to the drive signal, and during the at least one display period, the second switch is turned on according to the drive signal, and the controller generates a ground signal to the second switch according to the clock signal. The touch display device as described in claim 1 further includes: a color filter disposed on the display panel, and the conductive film layer is disposed on the color filter. The touch display device as described in claim 1 further includes: a cover glass disposed on the display panel, and the conductive film layer is disposed on the cover glass. The touch display device as described in claim 1 further includes: An optical film disposed on the display panel, and the conductive film layer is disposed on the optical film. A method for driving a touch display device includes: providing a display panel; providing a touch element array and a conductive film layer, so that the touch element array performs a touch detection action, wherein the conductive film layer is disposed on the touch element array and the display panel; in at least one display period, the conductive film layer receives a first reference voltage; and in at least one touch period other than the display period, the conductive film layer is in a floating state, wherein the touch element array is embedded in the display panel, and the conductive film layer is disposed on the touch element array and the display panel. A driving method as described in claim 11, wherein the at least one display period and the at least one touch period occur alternately in a frame cycle. A driving method as described in claim 11, wherein the conductive film layer is partially disposed on the display panel, and an overlapping area of the conductive film layer disposed on the display panel is less than half of the area of the plurality of sub-pixels of the display panel. The driving method as described in claim 11 further includes: providing a first switch, and making the first switch disconnected during the at least one touch period and turned on during the at least one display period; providing a clock generator, and making the clock generator generate a clock signal; providing a controller, and making the controller generate a driving signal to the first switch according to the clock signal; and providing a circuit board, and making the circuit board provide a power voltage to the clock generator. The driving method as described in claim 14, wherein during the at least one touch period, the controller generates the driving signal having a low gate voltage to the first switch according to the clock signal, and during the at least one display period, the controller generates the driving signal having a high gate voltage to the first switch according to the clock signal. The driving method as described in claim 14, wherein during the at least one touch period, the controller generates a pulse signal having a pulse height between a second reference voltage and a preset voltage to the touch element array according to the clock signal, and during the at least one display period, the controller maintains the pulse signal at a voltage level of the second reference voltage. The driving method as described in claim 14 further includes: providing a second switch; during the at least one touch period, the second switch is disconnected according to the driving signal; during the at least one display period, the second switch is turned on according to the driving signal, and the controller generates a ground signal to the second switch according to the clock signal. The driving method as described in claim 11 further includes: Providing a color filter, placing the color filter on the display panel, and placing the conductive film on the color filter. The driving method as described in claim 11 further includes: providing a cover glass, placing the cover glass on the display panel, and placing the conductive film layer on the cover glass. The driving method as described in claim 11 further includes: providing an optical film, placing the optical film on the display panel, and placing the conductive film layer on the optical film.

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