KR102043850B1 - Bidirectional touch sensing system - Google Patents

Abstract

The present invention relates to a bidirectional touch sensing system, comprising: first and second touch screens separately disposed with a cathode of a display panel interposed therebetween, a display panel driver for writing image data on the display panel, and the first and second And a touch screen driver for supplying a driving signal to the touch screen and sensing a touch input based on a change in capacitance of the touch sensors sensed by each of the first and second touch screens.

Description

Bidirectional Touch Sensing System {BIDIRECTIONAL TOUCH SENSING SYSTEM}

The present invention relates to a two-way touch sensing system.

A user interface (UI) enables communication between a person (user) and various electric and electronic devices, so that the user can easily control the device as desired. Representative examples of the 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. User interface technology continues to evolve in the direction of increasing user sensitivity and ease of operation. In recent years, user interfaces have evolved into touch UIs, voice recognition UIs, 3D UIs, and the like.

Touch UI is being adopted to portable information devices, and it is being applied to home appliances. The capacitive touch sensing system has the advantages that the touch screen structure has higher durability and clarity than the conventional resistive method, and can be applied to various applications because multi-touch recognition and proximity touch recognition are possible.

Various methods for incorporating a touch screen into an organic light emitting display device, which is drawing attention as a next-generation display device following the liquid crystal display, have been introduced. The pixels of the organic light emitting diode display include an organic light emitting diode (hereinafter referred to as "OLED") that is a self-luminous element. The organic light emitting diode display has advantages such as a faster response speed and no backlight than the liquid crystal display, and thus may be more power efficient and thinner. Such organic light emitting display devices are expected to be applied to mobile devices and soon to be used as display devices of televisions.

OLED displays are also being developed as transparent displays or flexible displays. In the transparent display, since the transparent image is simultaneously viewed from the front and rear of the display panel, the interactive touch UI is effective when implementing the touch UI. However, since the organic light emitting display device (hereinafter, referred to as “transparent organic light emitting display device”) implemented as a transparent display cannot implement a two-way touch UI due to its structural problem, when implementing a two-way touch UI when implemented as a transparent display. Is not easy.

1 is a view schematically illustrating a touch screen formed on a display panel of a transparent organic light emitting display device. The cathode 101 and the anode of the OLED are formed in the display panel 100 of the transparent organic light emitting display device. The cathode 101 is formed as one film in the entire pixel array, and is connected to the ground voltage source to supply the ground voltage GND. The touch screen 200 may be implemented as capacitive touch sensors. Such a touch screen determines that touch sensors with large capacity change before and after touch are touch sensors in which a touch input is generated. When viewing the touch screen 200 from the rear of the display panel 100, the cathode 101 of the display panel 100 forms a ground surface in front of the touch screen 100. Due to this ground surface, a touch of a finger or other conductor behind the display panel 100 may not cause a change in capacitance of the touch sensors. Therefore, the transparent organic light emitting display device as shown in FIG. 1 cannot implement a two-way touch UI because it is impossible to recognize a touch input input from the rear side of the display panel 100.

The present invention provides a bidirectional touch sensing system capable of implementing a bidirectional touch UI in a transparent organic light emitting diode display.

The bidirectional touch sensing system of the present invention comprises: a display panel in which an organic light emitting diode (OLED) having an anode and a cathode is disposed in pixels; First and second touch screens disposed separately with a cathode of the display panel interposed therebetween; A display panel driver for writing image data on the display panel; And a touch screen driver for supplying a driving signal to the first and second touch screens and detecting a touch input based on a change in capacitance of the touch sensors sensed by each of the first and second touch screens.

In accordance with another aspect of the present invention, a bidirectional touch sensing system includes: first and second display panels disposed with their rear surfaces facing each other; A first touch screen disposed on the first display panel; A second touch screen disposed on the second display panel; The background image of the first display panel captured by the second camera is combined with the first image data to be written on the first display panel, and the background image of the second display panel captured by the first camera is second. A display panel driver which writes to the second display panel in combination with image data; And a touch screen driver for supplying a driving signal to the first and second touch screens and detecting a touch input based on a change in capacitance of the touch sensors sensed by each of the first and second touch screens. Each of the first and second display panels includes pixels in which an organic light emitting diode OLED having an anode and a cathode is disposed. The first touch screen is disposed on the front substrate of the first display panel or between the front substrate of the first display panel and the cathode of the first display panel. The second touch screen is formed on the front substrate of the second display panel or disposed between the front substrate of the second display panel and the cathode of the second display panel.

The present invention can implement a two-way touch UI in a transparent organic light emitting diode display by separating the first and second touch screens with the cathode of the display panel interposed therebetween.

1 is a diagram schematically illustrating a touch screen formed on a display panel of an organic light emitting display device.
2 illustrates a two-way touch sensing system according to an embodiment of the present invention.
3 is a cross-sectional view illustrating an example of a cross-sectional structure of the display panel illustrated in FIG. 2.
FIG. 4 is a diagram illustrating driving parts of the display panel and the touch screen of FIG. 2.
5 is a diagram illustrating a bidirectional touch sensing system according to another embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like numbers refer to like elements throughout. In the following description, when it is determined that a detailed description of known functions or configurations related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

2 and 3, the bidirectional touch sensing system of the present invention includes first and second touch screens TSP1 and TSP2 disposed separately with the display panel DPNL interposed therebetween.

The display panel DPNL is a bidirectional transparent display panel that emits light of an image displayed on the pixel array to the front and the rear. The display panel DPNL includes data lines, scan lines (or gate lines) intersecting the data lines, and a pixel array in which pixels are arranged in a matrix. The pixels include an OLED, a driving device for adjusting a current flowing through the OLED according to a data voltage, a pixel driving circuit for controlling the driving device, and the like. In OLEDs, a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL) and an electron injection layer are formed between the cathode and the anode. Organic compound layers, such as (Electron Injection layer, EIL), are laminated. The pixel driving circuit includes one or more switch TFTs and a capacitor, and may be implemented by any known circuit. A color filter may be formed in the display panel DPNL to implement color.

The first touch screen TSP1 senses a touch input generated on the front surface of the display panel DPNL, and the second touch screen TSP2 senses a touch input generated on the rear surface of the display panel DPNL. The touch screens TSP1 and TSP2 include a plurality of touch sensors and wires for applying a driving signal to the touch sensors. The touch sensors can include capacitance. The touch screens TSP1 and TSP2 may be implemented as a touch screen of a self capacitance or mutual capacitance type.

The cathode of the OLED is disposed between the first and second touch screens TSP1 and TSP2. The first touch screen TSP1 may be formed on the front substrate 11 of the display panel DPNL or embedded in the display panel DPNL between the front substrate 11 and the cathode 13. The second touch screen TSP2 may be formed on the rear substrate 19 of the display panel DPNL or embedded in the display panel DPNL between the rear substrate 19 and the cathode 13. The front substrate 11 and the rear substrate 19 of the display panel DPNL may be made of a transparent glass substrate or a transparent film. The transparent film may be made of a polyethylene terephthlate (PET) film.

3 illustrates an example in which a first touch screen TSP1 is formed on the front substrate 11 and a second touch screen TSP2 is embedded in the display panel DPNL between the cathode 13 and the rear substrate 19. Although shown, the bidirectional touch screen structure of the present invention is not limited to FIG. For example, the first touch screen TSP1 may be embedded in the display panel DPNL between the front substrate 11 and the cathode 13, and the second touch screen TSP2 may be formed on the rear substrate 19. It may be. However, the cathode 13 should be disposed between the first and second touch screens TSP1 and TSP2 so that the bidirectional touch input is not blocked by the cathode 13.

In FIG. 3, a first transparent insulating film 18 is formed on the rear substrate 19, and a second touch screen TSP2 is formed thereon. The second transparent insulating layer 17 is formed on the second touch screen TSP2, and the TFT array 16 is formed thereon. The first and second transparent insulating layers 17 and 18 may be formed of an organic transparent insulating material or an inorganic transparent insulating material. For example, the first and second transparent insulating layers 17 and 18 may be formed of polyimide. The TFT array 16 includes data lines, scan lines, driving elements of pixels, and pixel driving circuits. An anode 15, an OLED 14, and a cathode 13 are stacked on the TFT array 16, and a transparent passivation 12 is formed on the cathode 13. The anode 15 and the cathode 13 may be formed of a transparent conductive material such as indium tin oxide (ITO) or a semi-transmissive metal film formed of a thin metal film to transmit light. The transparent protective film is formed of an organic insulating material or an inorganic insulating material. The front substrate 11 is formed on the transparent protective film 12, and the first touch screen TSP1 is bonded thereto.

Light generated by the emission of the OLED 14 is transmitted through the cathode 13, the transparent protective layer 12, the front substrate 11, and the first touch screen TSP1 to be emitted toward the front of the display panel DPNL. At the same time, the light generated by the emission of the OLED 14 is transmitted through the anode 15, the transparent insulating layer 17, the second touch screen TSP2, the transparent insulating layer 18, and the back substrate 19 to display the display panel DPNL. Is emitted to the rear of the frame. Accordingly, the display panel DPNL and the bidirectional touch screen of the present invention can implement a bidirectional transparent organic light emitting display device. The user may touch input the finger or the conductive material to the touch screens TSP1 and TSP2 disposed in front and rear of the display panel DPNL in both directions of the display panel DPNL.

FIG. 4 is a diagram illustrating driving units of the display panel DPNL and the touch screens TSP1 and TSP2 illustrated in FIG. 2.

Referring to FIG. 4, the display panel driver includes a timing controller 120 and a panel driving circuit 130. The panel driving circuit 130 writes input image data to the display panel DPNL including a data driving circuit, a scan driving circuit, and the like.

The data driving circuit converts the digital video data of the input image input from the timing controller 120 into an analog positive / negative gamma compensation voltage and outputs a data voltage. The data voltage output from the data driving circuit is supplied to the pixels through the data lines of the display panel DPNL. The scan driving circuit sequentially supplies a gate signal to the gate lines to select a line of the display panel DPNL to which a data voltage is written. The gate signal may include a scan signal synchronized with a data voltage, an emission control signal for controlling the emission timing of the OLED, an initialization signal for initializing pixels, and the like, but is not limited thereto.

The timing controller 120 rearranges the digital video data of the input image input from the host system 110 according to the pixel arrangement of the display panel DPNL and transmits the digital video data to the data driving circuit. The timing controller 120 receives timing signals such as a vertical synchronizing signal, a horizontal synchronizing signal, a data enable signal, a main clock, and the like input from the host system 110 to control the operation timing of the data driving circuit and the scan driving circuit.

The host system 110 transmits timing signals to the timing controller 120 together with the digital video data of the input image. The host system 110 executes an application program associated with the coordinate information XY of the touch input input from the algorithm execution unit 220.

The touch screen driver includes a sensing circuit 210 and an algorithm execution unit 220. The sensing circuit 210 senses a voltage change of the touch sensors by simultaneously supplying driving signals to the first and second touch screens TSP1 and TSP2 and transmits coordinate information of the touch input position to the algorithm execution unit 220. . The sensing circuit 210 converts the voltage of the touch sensor received from the first and second touch screens TSP1 and TSP2 into an analog-to-digital converter (ADC) in synchronization with the driving signal. It converts into digital data and outputs touch raw data. When the voltage change of the touch sensor is seen before and after the touch, when the touch sensor is touched, the capacitance value C of the touch sensor decreases at Q (charge) = C (capacity) x V (voltage). Accordingly, since the charge change amount of the touch sensor in which the touch input is generated is larger than that of the touch sensor without the touch input, the presence or absence of the touch input may be determined based on the difference in the charge change amount. The sensing circuit 210 may be integrated into a read-out integrated circuit (ROIC).

The algorithm execution unit 220 compares the touch raw data received from the sensing circuit 210 with a preset threshold by executing a preset touch recognition algorithm. Any known algorithm may be used as the touch recognition algorithm. The touch recognition algorithm detects touch raw data above a threshold. The touch raw data above the threshold is determined as touch data obtained from touch sensors in which a touch input is generated. The algorithm executing unit 220 executes a touch recognition algorithm to determine each touch data having a threshold value or more as a touch input, assigns an identification number to the touch inputs, and calculates coordinates. The algorithm execution unit 220 transmits a touch screen identification code indicating which touch screen is touched, and identification numbers and coordinate information of each of the touch inputs having a threshold value or more, to the host system 110. The algorithm execution unit 220 may be implemented as a micro controller unit (MCU).

5 is a diagram illustrating a bidirectional touch sensing system according to another embodiment of the present invention.

Referring to FIG. 5, the bidirectional touch sensing system according to the present invention may include the first and second display panels DPNL1 and DPNL2 and the first touch screen TSP1 formed on the front surface of the first display panel DPNL1. And a second touch screen TSP2 formed on the front surface of the second display panel DPNL2.

The first and second display panels DPNL1 and DPNL2 are display panels of the organic light emitting display device. The rear substrates of the first and second display panels DPNL1 and DPNL2 may be applied as opaque substrates or high reflectivity substrates. The front substrates of the first and second display panels DPNL1 and DPNL2 may be made of a transparent glass substrate or a transparent film. Light from the first display panel DPNL1 is transmitted through the first touch screen TSP1 to the front of the first display panel DPNL1. Light from the second display panel DPNL2 is transmitted through the second touch screen TSP2 to the front of the second display panel DPNL2. The first and second display panels DPNL1 and DPNL2 display background images captured by the cameras CAM1 and CAM2. Accordingly, the first and second display panels DPNL1 and DPNL2 and the first and second touch screens TSP1 and TSP2 implement a bidirectional transparent organic light emitting display device.

The first touch screen TSP1 senses a touch input generated on the front surface of the first display panel DPNL1, and the second touch screen TSP2 detects touch input generated on the front surface of the second display panel DPNL2. do. The touch screens TSP1 and TSP2 include a plurality of touch sensors and wires for applying a driving signal to the touch sensors. Touch sensors can include capacitance.

The first touch screen TSP1 may be formed on the front substrate of the first display panel DPNL1 or embedded in the first display panel DPNL1 between the front substrate and the cathode. The second touch screen TSP2 may be formed on the front substrate of the second display panel DPNL2 or embedded in the second display panel DPNL2 between the front substrate and the cathode.

The display panel driver includes first and second timing controllers 121 and 122 and first and second panel driver circuits 131 and 132. Each of the panel driving circuits 131 and 132 includes a data driving circuit, a scan driving circuit, and the like. The first panel driving circuit 131 writes first image data to the first display panel DPNL1 under the control of the first timing controller 121. The second panel driving circuit 132 writes second image data to the second display panel DPNL2 under the control of the second timing controller 122.

The first timing controller 121 rearranges the digital video data of the first image input from the host system 111 according to the pixel arrangement of the display panel DPNL and transmits the digital video data to the data driving circuit. The first timing controller 121 receives timing signals such as a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, a main clock, and the like, input from the host system 111, and the data driving circuit of the first panel driver circuit 131. And the operation timing of the scan driving circuit. The second timing controller 122 rearranges the digital video data of the second image input from the host system 111 according to the pixel arrangement of the display panel DPNL and transmits the digital video data to the data driving circuit. The second timing controller 122 receives timing signals such as a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, a main clock, and the like, input from the host system 111, and the data driving circuit of the second panel driver circuit 132. And the operation timing of the scan driving circuit.

The host system 111 outputs first and second image data capable of obtaining a transparent effect by combining the background image data captured by the cameras CAM1 and CAM2 with the first and second input image data. The host system 111 transmits timing signals synchronized with the image data to the first timing controller 121 together with the first image data. The host system 111 transmits timing signals synchronized with the image data to the second timing controller 122 together with the second image data. The host system 111 synchronizes the first and second timing controllers 121 and 122. In addition, the host system 111 executes an application program associated with the coordinate information XY of the touch input input from the coordinate conversion unit 231 of the touch screen driver.

The first camera CAM1 captures a front image of the first display panel DPNL1, that is, a rear background image of the second display panel DPNL2. The host system 111 transmits the background image received from the first camera CAM1 to the second timing controller 122 in combination with the second image data. Therefore, since the second display panel DPNL2 displays the background image obtained by the first camera CAM1, the second display panel DPNL2 can display an image such as a transparent display panel.

The second camera CAM2 captures a front image of the second display panel DPNL2, that is, a rear background image of the first display panel DPNL1. The host system 111 transmits the background image received from the second camera CAM2 to the first timing controller 121 in combination with the first image data. Therefore, since the first display panel DPNL1 displays the background image obtained by the second camera CAM2, the first display panel DPNL1 can display an image such as a transparent display panel.

The touch screen driver includes a sensing circuit 211, an algorithm execution unit 221, and a coordinate converter 231. The sensing circuit 211 simultaneously supplies driving signals to the first and second touch screens TSP1 and TSP2 to sense voltage changes of the touch sensors and transmits coordinate information of the touch input position to the algorithm execution unit 221. . The sensing circuit 211 outputs touch raw data by converting the voltages of the touch sensors received from the first and second touch screens TSP1 and TSP2 into digital data through an ADC in synchronization with the driving signal.

The algorithm execution unit 221 executes a preset touch recognition algorithm and compares the touch raw data received from the sensing circuit 211 with a preset threshold. Any known algorithm may be used as the touch recognition algorithm. The touch recognition algorithm detects touch raw data above a threshold. The touch raw data above the threshold is determined as touch data obtained from touch sensors in which a touch input is generated. The algorithm execution unit 221 executes a touch recognition algorithm to determine each touch data having a threshold value or more as a touch input, assigns an identification number to the touch inputs, and calculates coordinates. The algorithm execution unit 221 transmits a touch screen identification code indicating which touch screen is touched, identification numbers and coordinate information of each of the touch inputs having a threshold value or more, to the coordinate conversion unit 231.

In the state where the first and second display panels DPNL1 and DPNL2 face back, their display surfaces face each other in opposite directions. Therefore, when one of the first and second touch screens TSP1 and TSP2 is touched, the coordinates of the touch input position are reflected on the opposite layer touch screen as it is, and the virtual touch input position opposite to the actual touch input position is different. This requires a coordinate transformation process. The coordinate conversion unit 231 converts the coordinates of the actual touch input into the coordinates of the opposite touch screen so that the touch input position obtained when one touch screen is touched can be seen as the same position on another touch screen. Create For example, when the coordinate of the actual touch input generated in the first touch screen TSP1 is F (x, y) in FIG. 1 is different from the actual touch input position of the touch screen TSP1. The coordinate converting unit 231 converts the x coordinate from the coordinate F (x, y) of the actual touch input and matches the virtual touch input coordinate B (x ', y') corresponding to the actual touch input coordinate F (x, y). Occurs. The host system 111 executes an application program in which the actual touch input, the coordinate information, and the virtual touch input are associated with the coordinate information.

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.

DPNL, DPNL1, DPNL2: Display Panel TSP1, TSP2: Touch Screen
120 ~ 122: Timing controller 130 ~ 132: Panel driving circuit
210, 211: sensing circuit 220, 221: algorithm execution unit
231: coordinate conversion unit

Claims (6)

A display panel in which an organic light emitting diode having an anode and a cathode is disposed in pixels;
First and second touch screens disposed separately with a cathode of the display panel interposed therebetween;
A display panel driver for writing image data on the display panel; And
And a touch screen driver for supplying a driving signal to the first and second touch screens and sensing a touch input based on a change in capacitance of the touch sensors sensed by each of the first and second touch screens. Two-way touch sensing system. The method of claim 1,
The first touch screen is formed on the front substrate of the display panel or embedded in the display panel between the front substrate and the cathode,
And the second touch screen is formed on a rear substrate of the display panel or embedded in the display panel between the rear substrate and the cathode. First and second display panels disposed to face each other;
A first touch screen disposed on the first display panel;
A second touch screen disposed on the second display panel;
The background image of the first display panel captured by the second camera is combined with the first image data to be written on the first display panel, and the background image of the second display panel captured by the first camera is second. A display panel driver which writes to the second display panel in combination with image data; And
A touch screen driver for supplying a driving signal to the first and second touch screens and detecting a touch input based on a change in capacitance of the touch sensors sensed by each of the first and second touch screens,
Each of the first and second display panels includes pixels in which an organic light emitting diode having an anode and a cathode is disposed,
The first touch screen is disposed on the front substrate of the first display panel, or disposed between the front substrate of the first display panel and the cathode of the first display panel,
And the second touch screen is formed on the front substrate of the second display panel or disposed between the front substrate of the second display panel and the cathode of the second display panel. delete The method of claim 3, wherein
The rear substrate of each of the first and second display panels includes an opaque substrate or a high reflectivity substrate.
The front substrate of each of the first and second display panels includes a transparent substrate,
Light from the first display panel is transmitted through the first touch screen and the front substrate of the first display panel and emitted to the front of the first display panel.
And the light from the second display panel is transmitted through the second touch screen and the front substrate of the second display panel to the front of the second display panel. The method of claim 3, wherein
The touch screen driver,
The coordinates of the touch input are converted into the coordinates of the opposite touch screen so that the position of the touch input obtained when one of the first and second touch screens is touched can be seen as the same position on another touch screen. Bidirectional touch sensing system including a coordinate transformation unit for generating the coordinates.

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