Optical Touch System Floating Detection
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Solution Overview
Problem
Capacitive touch screens face challenges with sensitivity and intuition, particularly when detecting objects at a distance, leading to errors and requiring specialized stylus pens for accurate operation.
Innovation Solution
An optical touch system utilizing a light source module, image detecting modules, and a processing unit to determine object position and action based on light obstruction, allowing for intuitive and sensitive floating touch detection without the need for stylus pens, using a light source beside the base plane, reflecting units, and triangulation methods to calculate two-dimensional coordinates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive touch sensing is used to detect floating objects, then touch-sensing performance is improved, but sensitivity and intuition deteriorate when objects are at a distance
Solution Approach 1:
The patent replaces the capacitive sensing mechanism with an optical sensing mechanism. A light source emits light that passes through the touch screen, and when an object approaches or touches the screen, it obstructs the light path. This optical obstruction is detected by sensors, converting mechanical/optical interaction into an electrical signal for touch detection. This substitution resolves the sensitivity issue at distances because optical obstruction remains detectable even when capacitive coupling becomes too weak.
Solution Approach 2:
The patent introduces light as an intermediary medium between the touch object and the detection system. Instead of directly measuring capacitive changes from the object, the system uses light transmission and obstruction as an intermediate physical phenomenon to indirectly detect the object's presence and position. This intermediary approach maintains high sensitivity across varying distances.
2Adaptability or versatility
If capacitive touch sensing is used, then touch detection capability is improved, but the need for specialized stylus pens increases
Solution Approach 1:
The optical sensing system is designed to detect various types of objects universally - fingers, stylus pens, or any other objects that can obstruct light. The detection mechanism does not depend on the electrical properties of the object (as capacitive sensing does), but rather on its physical presence blocking the light path. This universality eliminates the need for specialized capacitive stylus pens while maintaining broad touch detection capability.
Solution Approach 2:
By substituting capacitive sensing with optical sensing, the system becomes insensitive to the electrical characteristics of the touching object. This allows any object that can physically block light to interact with the touch interface, greatly enhancing ease of operation and intuitiveness without requiring users to learn specialized stylus usage.
3Ease of operation
If floating touch sensing is implemented, then user convenience is improved, but detection accuracy deteriorates when objects are slightly distant
Solution Approach 1:
The patent replaces capacitive field detection with direct optical path detection. In capacitive systems, the electric field strength diminishes rapidly with distance, causing detection accuracy to drop. In contrast, the optical system detects light obstruction, which remains detectable over longer distances and provides more consistent measurement precision across the full range of floating touch distances, thereby maintaining both convenience and accuracy.
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 user convenience and intuitiveness by accurately detecting object proximity and action, reducing errors and the need for specialized tools, while maintaining high sensitivity across varying distances and sizes.
Implementation Method 1
The light source module is disposed beside the base plane, and provides a detecting light in which the detecting light is transmitted in front of the base plane. The image detecting module is disposed beside the base plane, and detects an intensity variation of the detecting light.
Implementation Method 2
at least a portion of the detecting light is obstructed by the object when the object approaches or touches the base plane
Data Source
AI summary
An optical touch system includes a light source module, at least one image detecting module and a processing unit. The light source module provides a detecting light. The detecting light is transmitted in front of the base plane. The image detecting module detects an intensity variation of the detecting light. The image detecting module generates a detecting signal corresponding to the detecting light. When an object approaches or touches the base plane, at least a portion of the detecting light is obstructed by the object. The processing unit determines a position of the object with respect to the base plane according to the detecting signal, and determines that the object approaches or touches the base plane according to an intensity of a portion of the detecting signal corresponding to an obstruction position of the object. A method of touch detection and a computer program product are also provided.