Contactless Touch Input Optics for Precise Low-Cost Gesture Sensing
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Solution Overview
Problem
Existing proximity sensors are either too costly and complex for large screen applications due to the need for high-resolution detection of absolute coordinates, or they lack the necessary precision for gesture detection in rugged environments, and there is a need for cost-effective, accurate contactless user interfaces for public and sterile environments.
Innovation Solution
A low-cost proximity sensor design using extruded plastic lenses for collimating light in one dimension and a Fresnel lens array for another, combined with a processor to identify gestures by synchronizing light emitters and detectors, allowing for the use of multiple small sensors to cover larger areas and tolerate systematic errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution proximity sensors are used for touchscreen applications, then detection precision is improved, but manufacturing cost and device complexity increase significantly
Solution Approach 1:
The patent divides the detection task into segments by using multiple low-resolution sensors instead of one high-resolution sensor. Each sensor covers a portion of the detection area, and the system processes signals from multiple sensors to achieve comprehensive gesture detection. This segmentation approach reduces the complexity and cost of individual sensors while maintaining overall system effectiveness.
Solution Approach 2:
The patent applies local quality by using different sensor resolutions for different applications. Instead of uniformly high resolution across the entire detection area, the system uses multiple lower-resolution sensors positioned to cover specific regions, optimizing resource allocation and reducing overall system complexity while maintaining adequate detection capability for gesture recognition.
2Ease of manufacture
If multiple small sensors are used to cover larger screen areas, then manufacturing cost is reduced, but detection precision and coverage area are compromised
Solution Approach 1:
The patent merges the functionality of multiple small sensors to achieve comprehensive coverage. By combining signals from multiple low-resolution sensors positioned across the detection area, the system reconstructs a complete picture of gestures, effectively merging their individual coverage areas to match or exceed that of a single high-resolution sensor while reducing manufacturing costs.
Solution Approach 2:
The patent transitions from a single-dimension approach (one high-resolution sensor) to a multi-dimensional approach (multiple low-resolution sensors arranged in space). By distributing sensors across different positions and processing their combined signals, the system achieves comprehensive coverage through spatial arrangement rather than relying on a single sensor's resolution, effectively adding a dimensional aspect to the detection architecture.
3Reliability
If contactless user interfaces are implemented for public terminals, then hygiene and reliability are improved, but system complexity and cost increase
Solution Approach 1:
The patent replaces mechanical contact-based interfaces with an optical detection system. Instead of requiring physical touch of buttons or screens, the system uses light-based proximity sensing to detect gestures in the air above the interface. This substitution eliminates the need for mechanical contact, improving hygiene and reliability for public terminals while using relatively simple optical components to achieve the contactless functionality.
4Ease of manufacture
If automated assembly equipment limitations are considered, then manufacturing simplicity is improved, but maximum sensor length and screen size coverage are reduced
Solution Approach 1:
The patent segments the overall sensor system into multiple smaller, standardized sensor modules that can be manufactured within the capabilities of existing automated assembly equipment. Each module has a manageable length suitable for current assembly technology, and multiple modules are combined to cover larger screen areas, thus respecting manufacturing limitations while achieving the required coverage through modular construction.
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 accurate and cost-effective gesture detection and contactless user interfaces, suitable for various applications including public terminals and sterile environments, while reducing manufacturing complexity and costs by using modular optics and standard components.
Implementation Method 1
employing an extruded plastic lens to collimate light in a first dimension
Implementation Method 2
a Fresnel lens array to collimate light in a second dimension
Implementation Method 3
a reflective object located in the projection plane above the at least one lens reflects light projected at the reflective object from an emitter to one or more of the detectors
Data Source
AI summary
A proximity sensor, including light emitters and light detectors mounted on a circuit board, two stacked lenses, positioned above the emitters and the detectors, including an extruded cylindrical lens and a Fresnel lens array, wherein each emitter projects light through the two lenses along a common projection plane, wherein a reflective object located in the projection plane reflects light from one or more emitters to one or more detectors, and wherein each emitter-detector pair, when synchronously activated, generates a greatest detection signal at the activated detector when the reflective object is located at a specific 2D location in the projection plane corresponding to the emitter-detector pair, and a processor sequentially activating the emitters and synchronously co-activating one or more detectors, and identifying a location of the object in the projection plane, based on amounts of light detected by the detector of each synchronously activated emitter-detector pair.