Sloped Optical Touch Panel Light Path Geometry
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Solution Overview
Problem
Conventional optical touch panel inputting devices face issues with misdetecting foreign materials as touch inputs and poor responsiveness, especially when users touch the screen with their fingertips, due to the parallel scanning light path plane configuration which fails to accurately detect light blocking areas at varying touch locations and angles.
Innovation Solution
A touch panel inputting device with a scanning light path plane that slopes at a prescribed angle from one end to the other end of the operation surface, featuring multiple scanning light paths to improve light blocking area detection and responsiveness by adjusting the distance between the scanning light path planes and the operation surface, allowing for better detection of fingertip touches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the scanning light path plane is configured parallel to the operation surface, then the structure is simple and easy to manufacture, but the light blocking area detection accuracy deteriorates when users touch with fingertips at varying angles
Solution Approach 1:
The patent applies asymmetry by changing the scanning light path plane from a parallel configuration to a sloped configuration relative to the operation surface. This asymmetric arrangement allows the light paths to intersect the operation surface at an angle, creating a larger effective detection area for fingertip touches while maintaining structural feasibility through the defined slope angle configuration
2Volume of moving object
If the scanning light path plane is close to the operation surface, then the device structure is compact, but the responsiveness to fingertip touches deteriorates due to insufficient light blocking area
Solution Approach 1:
The sloped configuration creates asymmetric light path geometry where the effective detection area is expanded in the horizontal direction while maintaining vertical compactness. This allows the device to remain compact while achieving larger light blocking areas for fingertip detection through the angular intersection of light paths with the operation surface
3Measurement precision
If the scanning light path plane is configured to detect small light blocking areas, then foreign material detection accuracy improves, but fingertip touch detection reliability deteriorates
Solution Approach 1:
The sloped scanning light path configuration creates local quality variations in the detection sensitivity across different regions of the operation surface. The angle of incidence varies across the surface, creating zones with different light blocking characteristics that can be optimized to distinguish between fingertip touches and foreign materials based on their different spatial signatures
4Area of stationary object
If the scanning light paths are arranged in a grid pattern, then the detection coverage is complete, but the complexity of the device increases
Solution Approach 1:
The patent segments the scanning light paths into two distinct sets: first scanning light paths extending in one direction and second scanning light paths extending in another direction. This segmentation allows the complex grid-like coverage to be achieved through modular, directional light path arrangements rather than a monolithic complex structure, simplifying the overall configuration
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
Enhances operational responsiveness and consistency by increasing the light blocking area margin for fingertip touches, reducing false detection of foreign materials and improving touch detection accuracy across the operation surface.
Implementation Method 1
The light emitting elements array is configured with a plurality of LEDs (Light Emitting Diodes)
Implementation Method 2
The light reception elements array is configured with a plurality of PDs (Photodiodes). The optical touch panel inputting device receives light emitted from each of LEDs at each of PDs to scan operation surface CP. The optical touch panel inputting device determines the touched position, based on the location of the PD at which the light receiving amount is reduced
Data Source
AI summary
The touch panel inputting device which is installed on a flat operation surface for receiving an operation performed by a operation body, detects a contact location of the operation body on the operation surface, based on light blocking of a flat scanning light path plane. The touch panel inputting device comprises: a first scanning light paths forming unit for forming first scanning light paths which are linear; and a second scanning light paths forming unit for forming second scanning light paths which are linear and intersect with the first scanning light paths. The first and the second scanning light paths form the scanning light path plane, and the scanning light path plane slopes with respect to the operation surface.