Optical Touch Screen Using Perpendicular Mirror for Uniform Light Distribution
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Solution Overview
Problem
Conventional optical touch structures require multiple light source assemblies and image sensors, leading to higher costs, increased weight, and energy consumption, while also resulting in non-uniform light distribution that affects sensing accuracy.
Innovation Solution
The optical touch device employs a light guide element, a light source, and an image sensor, with a reflecting mirror positioned perpendicularly to the light guide element, ensuring that the light emitted is distributed uniformly across the sensing area, using fewer components and optimizing light path lengths to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple light source assemblies and image sensors are used, then the touch sensing coverage is improved, but the device complexity, cost, and energy consumption increase
Solution Approach 1:
The patent combines multiple light sources into a single light source assembly that emits light in multiple directions simultaneously. It also merges multiple image sensors into a single image sensor with a large sensing area, thereby reducing the total number of components while maintaining comprehensive touch sensing coverage across the entire display surface
Solution Approach 2:
The single image sensor is designed to perform multiple functions by detecting touch points at different positions and angles simultaneously through its large sensing area and optical system, replacing what would traditionally require multiple specialized sensors positioned at different locations
2Area of stationary object
If multiple light source assemblies are used, then the touch sensing coverage is improved, but the weight and energy consumption increase
Solution Approach 1:
The patent consolidates multiple light emitting elements into a single light source assembly that can illuminate the entire touch sensing area simultaneously, reducing the total energy consumption while maintaining comprehensive coverage through optimized optical path design
3Measurement precision
If multiple image sensors are used, then the touch detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent integrates multiple detection functions into a single image sensor by designing an optical system that directs light from different angles and positions to the same sensor, enabling accurate touch detection across the entire display surface without requiring multiple separate sensors
Solution Approach 2:
The patent introduces optical dimensionality by using mirrors and light guides to redirect light paths, allowing a single image sensor to receive information from multiple spatial dimensions and angles, thereby achieving high detection accuracy without increasing the number of sensors
4Length of stationary object
If light is emitted directly without reflection, then the light path is shortened, but the light distribution uniformity deteriorates
Solution Approach 1:
The patent introduces mirrors as intermediary elements that redirect light paths to reach different regions of the display surface. These mirrors act as mediators that extend the effective light path length while distributing light uniformly across the entire sensing area, solving the contradiction between short path length and uniform distribution
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 reduces the number of light sources and image sensors, lowering costs and energy consumption while maintaining or improving sensing accuracy by ensuring uniform light distribution and precise calculation of touch points.
Implementation Method 1
The light guide element guides the light provided by the light source to the light-emitting surface
Implementation Method 2
a second direction light transmitted towards the image sensor through the reflecting mirror
Data Source
AI summary
An optical touch structure including a light guide element, a light source, a reflecting mirror, and an image sensor is provided. The light guide element has a light-emitting surface. The light guide element guides the light provided by the light source to the light-emitting surface. The extending direction of the reflecting mirror is substantially perpendicular to the light-emitting surface. The intersection of the reflecting mirror and the light guide element is defined as a first position. The light guide element and the reflecting mirror define a touch range. The image sensor is disposed on a second position opposite to the first position. The sensing area of the image sensor at least covers the touch range. When the proceeding path of the first direction light is shorter than that of the second direction light, the strength of the second direction light is larger than that of the first direction light.