Optical Touch System with Segmented Light Compensation
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Solution Overview
Problem
Conventional optical touch systems face challenges in accurately determining the number of touch objects and their precise positions due to 'face to face' issues between optical modules, leading to confusion and incorrect recognition of touch inputs, especially when additional modules are added for multi-touch sensing.
Innovation Solution
The optical touch system employs a configuration where sensing modules are divided into two groups, with one group emitting sensing light and the other emitting compensation light to address low-brightness areas caused by gaps in the reflection structure, ensuring accurate touch input detection by compensating for dark points and maintaining high sensing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If more optical modules are added to sense multiple touch positions, then the touch sensing capability is improved, but the 'face to face' problem occurs causing incorrect recognition
Solution Approach 1:
The optical modules are divided into two groups: first group modules emit sensing light toward the second section, while second group modules emit compensation light toward the first section. This segmentation resolves the face-to-face problem by ensuring each group's light is reflected by reflection frames not occupied by the other group's modules, maintaining reliable touch recognition.
Solution Approach 2:
The reflection structure acts as an intermediary that reflects sensing light from the first group and compensation light from the second group to the sensing units. This intermediary mechanism enables multi-touch sensing while preventing direct face-to-face interference between opposite optical modules.
2Area of stationary object
If optical modules are disposed at positions without reflection frame to enable multi-touch sensing, then the sensing coverage is improved, but dark points are created causing false touch detection
Solution Approach 1:
Different regions of the periphery are assigned different functions: first section modules emit sensing light, second section modules emit compensation light. The reflection structure is configured with reflection frames at specific positions to reflect light appropriately. This local differentiation ensures that modules at positions without reflection frames still function correctly by receiving compensated light, eliminating dark points while maintaining sensing coverage.
Solution Approach 2:
The second group modules create a copy of the sensing function by emitting compensation light in response to the sensing light from the first group. This copying mechanism ensures that positions without reflection frames still receive sufficient light intensity, preventing false dark point detections while expanding sensing coverage.
3Measurement precision
If compensation light is emitted by second group modules, then the low-brightness area is compensated improving sensing accuracy, but the device complexity increases
Solution Approach 1:
Both first group and second group modules serve dual functions: they can emit sensing light or compensation light depending on the operational mode. The sensing units in both groups can detect both sensing light and compensation light. This multi-functionality reduces the need for separate dedicated components, managing device complexity while maintaining high sensing accuracy through compensation.
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 enables precise determination of touch objects and their positions, enhancing multi-touch sensing capabilities while maintaining low manufacturing costs, thus overcoming the limitations of conventional systems.
Implementation Method 1
each of the light-emitting units is adapted to emit a sensing light
Implementation Method 2
the sensing light is reflected by the reflection structure
Implementation Method 3
each of the sensing units is adapted to sense a brightness value distribution of the sensing light
Data Source
AI summary
An optical touch system including a touch surface, a reflection structure and light source modules is provided. The reflection structure and the light source modules are disposed at a periphery of the touch surface. Each light source module has a light-emitting unit and a sensing unit. The sensing unit obtains a brightness value distribution of a sensing light emitted by the light-emitting unit after the sensing light is reflected by the reflection structure, so as to sense touch input. The periphery of the touch surface includes first and second sections. When the light-emitting unit located on the first section emits the sensing light, the sensing light is not reflected by the reflection structure at the light source modules located on the second section so that low-brightness areas are formed, and the light-emitting units of the second group emit compensation lights correspondingly. In addition, a touch sensing method is also provided.