Optical Touch Display Using Image Map for High-Speed Sensing
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Solution Overview
Problem
Existing touch screen technologies, such as infrared and in-cell capacitive types, face challenges in manufacturing complexity, cost, and performance due to increased parasitic capacitance and size limitations, which hinder high-speed and multi-touch sensing capabilities.
Innovation Solution
An optical touch display device utilizes an image map, where source image data is corrected and alternately displayed with the image map, allowing an optical touch pen with a built-in camera to sense touch positions using position information mapped onto the image data, eliminating the need for physical touch electrodes and reducing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an infrared camera is used for touch sensing, then touch sensing capability is achieved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent uses a color map image that is a visual copy or representation of coordinate information, replacing the need for complex infrared camera hardware. The color map encodes position data in a visual format that can be captured by standard imaging components, thereby achieving touch sensing with simpler devices.
Solution Approach 2:
The patent replaces the mechanical/optical infrared sensing system with an image processing-based system. Instead of using infrared cameras to detect touch positions directly, the system uses color-coded coordinate maps that can be processed through image analysis, substituting a complex optical detection system with a simpler image processing approach.
2Ease of operation
If touch electrodes are formed in display panel cells, then in-cell touch design is achieved, but parasitic capacitance increases and sensing performance deteriorates
Solution Approach 1:
The patent replaces the electrical capacitive sensing mechanism with an optical/image processing mechanism. Instead of relying on capacitive changes detected by electrodes, the system uses color-coded coordinate information captured through imaging, thereby eliminating parasitic capacitance issues while maintaining sensing functionality.
Solution Approach 2:
The patent extracts the coordinate sensing function from the electrical domain (touch electrodes and capacitive sensing) and transfers it to the optical/image processing domain. By taking out the sensing function from the electrical system and implementing it through image analysis of color maps, the patent eliminates the harmful parasitic capacitance while preserving touch detection capability.
3Reliability
If drive and reception electrode lines are formed to cross, then touch signal transmission is achieved, but manufacturing processes and complexity increase
Solution Approach 1:
The patent replaces the electrical signal transmission system with an optical/image-based system. Instead of using drive and reception electrode lines to transmit touch signals, the system uses color-coded coordinate maps that encode position information visually, eliminating the need for complex electrode line routing and reducing manufacturing complexity.
4Area of stationary object
If screen size is increased, then display area is improved, but parasitic capacitance increases and sensing performance decreases
Solution Approach 1:
The patent replaces the electrical capacitive sensing system with an optical/image processing system that is not subject to parasitic capacitance limitations. By using color-coded coordinate maps that can be captured and processed optically, the system maintains sensing performance across large display areas without the performance degradation caused by increased parasitic capacitance in electrical systems.
Data Source
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AI summary
An optical touch display device which is advantageous in high-speed driving, large-area touch sensing, and multi-touch sensing because of use of an image map and which can improve touch sensing performance and a driving method thereof are provided. The optical touch display device includes a display device configured to display a display image based on input source image data and an image map for touch sensing, an optical touch pen configured to detect map information of the image map displayed on the display device, and a position detector configured to detect position information (coordinate information) on a screen based on the map information.