Optical Touch Pad Waveguide Light Redirection for Position Encoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current optical touch-sensitive devices are costly to manufacture and lack efficient methods for accurately determining the position and position change of an object contacting the surface.
Innovation Solution
A touch-sensitive device comprising a light source, a touch-sensitive waveguide, a detector array, and a first light redirecting member, where the light source emits light that is guided through the waveguide to a touch-sensitive surface, and the detector array detects changes in light intensity caused by an object contacting the surface, with the light redirecting member redirecting light to prevent it from reaching specific points on the detector array, allowing for precise position encoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional optical touch-sensitive devices are used, then position detection functionality is provided, but manufacturing cost is high
Solution Approach 1:
The device segments the light detection function by using a waveguide that guides light from multiple light sources to a single detector array. This segmentation allows the system to achieve accurate position detection through spatial encoding of light paths while using fewer expensive components, thereby reducing manufacturing cost without sacrificing precision
Solution Approach 2:
The waveguide acts as an intermediary element that transfers and encodes light information from multiple sources to the detector array. This intermediary structure enables cost-effective position detection by spatially encoding the contact position through the guided light paths, eliminating the need for expensive direct detection at multiple points
2Measurement precision
If light is allowed to propagate directly to the detector array, then simple light path is achieved, but position encoding precision is insufficient
Solution Approach 1:
The waveguide pre-encodes the spatial information of light sources before detection by guiding light along specific paths determined by the contact position. This preliminary spatial encoding action enables precise position detection when the light reaches the detector array, achieving high precision without requiring complex post-processing or additional optical elements
Solution Approach 2:
The system uses the waveguide to add a spatial dimension to light propagation, where light travels through the waveguide at angles determined by the contact position. This dimensional encoding of light paths allows the single detector array to resolve two-dimensional contact positions, achieving precise position encoding without requiring multiple detectors at each position
3Area of stationary object
If multiple light sources are used for comprehensive coverage, then detection coverage is improved, but determining the specific light source responsible for disturbed light becomes difficult
Solution Approach 1:
The waveguide provides locally differentiated light paths for each light source, where the spatial encoding of light propagation is unique to each source's position and angle. This local quality differentiation in the guided light paths allows the system to easily identify which specific light source's light was disturbed at the contact point, even with multiple light sources providing comprehensive coverage
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
Enables the accurate determination of an object's position and position change on the touch-sensitive surface at a low manufacturing cost, providing effective position encoding and allowing for the detection of contact points with high precision.
Implementation Method 1
a touch-sensitive waveguide configured for guiding light from the light source towards a touch-sensitive surface of the touch-sensitive waveguide
Implementation Method 2
a first light redirecting member configured for redirecting light having propagated from the light source through the touch-sensitive waveguide and to the first light redirecting member towards the detector array
Implementation Method 3
a detector array configured for detecting intensity distribution of light having propagated from the light source through the touch-sensitive waveguide for position encoding the contact point
Data Source
AI summary
The present invention relates to an optical touch-sensitive device and a method of determining a position and determining a position change of an object contacting an optical touch sensitive device. In particular, the present invention relates to an optical touch pad and a method of determining a position and determining a position change of an object contacting an optical touch pad. A touch-sensitive device, according to the present invention may comprise a light source, a touch-sensitive waveguide, a detector array, and a first light redirecting member, wherein at least a part of the light propagating towards a specific point of the detector array is prevented from being incident upon the specific point of the detector array when an object contacts a touch-sensitive surface of the touch-sensitive waveguide at a corresponding specific contact point.