Optical Touch System Using Light Guide Plate for Thin Frame Design
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Solution Overview
Problem
Current optical touch systems are complex, costly, and prone to interference, with capacitive touch systems being unstable due to temperature and humidity variations, and optical touch systems requiring complex camera setups that are inconvenient for users.
Innovation Solution
An optical touch system comprising an optical unit and an image acquisition unit on a physical plane, where the optical unit produces a first optical effect and the image acquisition unit captures a second optical effect after a touch operation, using light sources and optical components like light guide plates or optical fibers to determine the touch range with reduced frame thickness and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a camera is arranged above the screen to capture finger movements, then touch positioning can be achieved, but the structure becomes complex and the cost increases
Solution Approach 1:
The patent combines the light source and optical components directly into the screen frame structure, eliminating the need for a separate camera above the screen. The light guide plate is integrated into the frame, and the imaging is performed by capturing light patterns directly at the screen plane, merging multiple components into a unified structure that reduces complexity while maintaining positioning accuracy
Solution Approach 2:
The patent extracts the camera from the traditional overhead position and replaces it with light guide plates and optical components integrated into the screen frame. This extraction simplifies the overall structure by removing the need for a separate imaging device positioned above the screen, while still achieving the required touch detection functionality
2Area of stationary object
If the camera is positioned away from the touch area to capture the whole touch area, then complete touch detection is achieved, but the apparatus becomes more complex and less convenient for users
Solution Approach 1:
The patent transitions from a vertical arrangement (camera above the screen) to a planar integration (optical components within the screen frame). By positioning light guide plates and optical components in the same plane as the touch screen, the system achieves full touch area coverage while maintaining a compact, user-friendly design that does not protrude or require additional space above the display
3Adaptability or versatility
If transparent conductive material is attached onto the screen for capacitive touch, then touch functionality is achieved, but the cost increases and stability decreases due to temperature and humidity variations
Solution Approach 1:
The patent replaces the capacitive touch mechanism (which relies on electrical properties of transparent conductive materials) with an optical touch mechanism using light guide plates and light pattern recognition. This substitution eliminates the dependency on materials whose properties vary with temperature and humidity, providing more stable and reliable touch detection across different environmental conditions
4Reliability
If a protective layer is added on top of the light source, then the light source is protected, but the frame thickness increases
Solution Approach 1:
The patent nests the protective layer within the existing frame structure by positioning it between the light guide plate and the front surface of the screen. This nested arrangement allows the protective function to be integrated without adding external thickness, as the protective layer is embedded within the existing structural boundaries rather than adding to them
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system reduces ambient interference, improves touch operation accuracy, simplifies the structure, and lowers costs by using a single optical component with a protective layer, and reduces frame thickness when using two optical components, making it suitable for lightweight and thin products like keyboards and laptops.
Implementation Method 1
a light guide plate set on the physical plane, the light guide plate having an end face facing the point light source and configured to scatter light from the point light source onto the physical plane
Implementation Method 2
an optical fiber set on the physical plane, the optical fiber having an end face facing the point light source and configured to receive light from the point light source and scatter the light from the point light source through a side face of the optical fiber
Implementation Method 3
a reflective film located on one side of a main body portion of the light guide plate and configured to reflect the light propagated within the light guide plate
Implementation Method 4
a scattering film located on the other side of the main body portion of the light guide plate and configured to scatter the light reflected by the reflective film onto the physical plane
Data Source
AI summary
The present invention provides an optical touch system, applied to an electronic apparatus having at least a physical plane. It comprises: an optical unit set on the physical plane and configured to produce a first optical effect; an image acquisition unit set on the physical plane, at least a part of the optical unit being within an acquisition range of the image acquisition unit, a touch operation area being formed by the image acquisition unit and the optical unit; the image acquisition unit configured to capture an image having a second optical effect which is formed on the first optical effect after an operation body for operating the electronic apparatus enters the touch operation area; a processing unit being connected with the image acquisition unit and configured to determine the range of the operation body in the touch operation area according to the image having the second optical effect. The present invention also provides an optical touch input display apparatus and optical touch input positioning method. The touch system of the present invention is low-cost and highly reliable.