Photo Sensing Device Coupling Unit Enhances Touch Detection
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Solution Overview
Problem
Optical touch display panels struggle to accurately determine touch events in varying light conditions due to small signal strength differences between touch and non-touch events, especially in weak external light environments.
Innovation Solution
A photo sensing device with a coupling unit enhances the sensitivity of the photo sensing unit, increasing the difference between judging signals for touch and non-touch events, allowing accurate detection regardless of light intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a photo sensing device operates in weak external light conditions, then power consumption is reduced, but the signal strength difference between touch and non-touch events becomes too small for accurate detection
Solution Approach 1:
The patent introduces a light source (such as an LED or laser) as an intermediary element that actively illuminates the touch panel from behind. This light source creates a controlled optical path where touch events modulate the light intensity reaching the photo sensing device. By using this intermediary light source, the system can operate in dark environments without relying on weak external light, thereby maintaining both low power consumption and high detection accuracy.
Solution Approach 2:
The patent changes the operating parameters of the photo sensing device by using modulation techniques. The light source is modulated at a specific frequency, and the photo sensing device is tuned to detect signals at this frequency. This parameter change allows the system to distinguish touch-induced signal variations from background noise even in weak light conditions, maintaining measurement precision while enabling operation with lower overall power consumption.
2Device complexity
If the photo sensing device relies on external light intensity, then device complexity is reduced, but adaptability to different environmental light conditions deteriorates
Solution Approach 1:
The patent implements a dynamic system where the light source can be turned on or off based on environmental conditions. A control circuit monitors the ambient light level and automatically activates the backlight light source when external light is insufficient. This dynamic adaptation allows the device to maintain consistent performance across varying environmental light conditions without requiring complex hardware modifications for each condition.
Solution Approach 2:
The patent makes the light source serve multiple functions: it acts as a backlight for display visibility and simultaneously serves as an illumination source for the photo sensing device. This multi-functionality allows the system to adapt to different environmental light conditions using a single integrated solution, maintaining device simplicity while achieving broad environmental adaptability.
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 enhanced photo sensing device provides accurate touch event detection in both strong and weak light conditions, enabling the optical touch display panel to be used in diverse environmental settings.
Implementation Method 1
a photo sensing unit 201 and a coupling unit 203. The photo sensing unit 201 is used for sensing whether a touch event is occurred or not, and accordingly outputting a judging signal
Data Source
AI summary
A photo sensing device suitable for an optical touch display panel and applications thereof are provided. The photo sensing device includes a photo sensing unit and a coupling unit. The photo sensing unit is used for sensing whether a touch event is happened/occurred or not, and accordingly outputting a judging signal. The coupling unit is coupled to the photo sensing unit, and is used for enhancing the sensitivity of the sensing unit, so as to increase a difference between the judging signal associated with occurrence of the touch event and the judging signal associated with non-occurrence of the touch event.