Optical Touch Device Diagonal Sensor Arrangement
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Solution Overview
Problem
Conventional optical touch devices struggle to accurately determine the number of touch points, especially when multiple fingers are used, leading to mis-identification and interference.
Innovation Solution
The optical touch device employs a configuration with four image sensing units arranged diagonally on opposite edges of an indication plane, where the processing unit calculates touch points by analyzing images from pairs of sensing units to determine the number of touch points within specific angles, ensuring accurate identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two image sensing units are used for sensing touch points, then the device structure is simple, but the accuracy of determining multiple touch points deteriorates
Solution Approach 1:
The patent divides the touch sensing function into multiple independent image sensing units (first, second, third, and fourth units) positioned at different edges of the indication plane. Each unit independently captures images of touch points from its specific viewpoint, allowing the system to segment the complex task of detecting multiple touch points into simpler sub-tasks that can be processed independently and then combined for accurate determination of all touch points.
2Measurement precision
If multiple image sensing units are arranged to improve touch point detection accuracy, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent positions the four image sensing units at different spatial locations around the indication plane (first and second units on one edge, third and fourth units on the opposite edge), creating a multi-dimensional sensing arrangement. This spatial distribution allows each sensor to capture touch information from different angles and perspectives, enabling accurate determination of multiple touch points through geometric relationships without requiring an overly complex centralized sensing system.
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
This configuration enhances the accuracy of determining touch points, preventing mis-identification and enabling precise execution of touch functions, even with multiple fingers.
Implementation Method 1
When a touch gesture is performed on the central touch area, the first image sensing unit senses a first image, the second image sensing unit senses a second image, the third image sensing unit senses a third image and the fourth image sensing unit senses a fourth image
Data Source
AI summary
An optical touch device utilizes two images sensed by two image sensing units, which are diagonal to each other, to determine whether a number of touch points located at a central touch area is equal to 1. When the number of touch points are larger than 1, the optical touch device further utilizes another two images sensed by another two image sensing units, which are also diagonal to each other, to assist in determining the number of touch points located at the central touch area, so as to improve the accuracy of determination.