Optical Gesture Sensor Layout for Low-Cost Large Touch Surfaces
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Solution Overview
Problem
Existing proximity sensors face challenges in cost and manufacturing efficiency, particularly for large screen sizes and rugged environments, where high-resolution detection is not always necessary, and there is a need for contactless user interfaces to prevent contamination and improve usability.
Innovation Solution
The development of a low-cost proximity sensor using an extruded plastic lens for collimating light in one dimension and a Fresnel lens array for the second dimension, allowing for accurate gesture detection with tolerance for systematic errors, and enabling the use of multiple small sensors for larger screen sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution proximity sensors are used for touch detection, then detection precision is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent divides the detection task into multiple lower-resolution sensors working together rather than using a single high-resolution sensor. Multiple sensors scan different regions and combine their data to achieve accurate touch detection, reducing individual sensor complexity while maintaining overall system precision.
Solution Approach 2:
The system uses multiple sensors that collectively cover the detection area with overlapping fields of view. Each sensor provides partial detection coverage, and through coordinated scanning and data fusion, the system achieves complete and accurate touch detection without requiring each individual sensor to be highly complex.
2Area of stationary object
If sensors are extended along the entire edge of the screen for large screens, then detection coverage is improved, but manufacturing cost increases due to automation limitations
Solution Approach 1:
Instead of using a single long sensor extending along the entire screen edge, the patent employs multiple shorter sensors positioned at different locations. Each sensor covers a specific region, and together they provide complete edge coverage. This segmentation allows standard automated assembly equipment to handle each shorter sensor individually, reducing manufacturing cost while maintaining full detection coverage.
3Ease of operation
If contactless user interfaces are implemented, then hygiene and usability are improved, but system complexity increases
Solution Approach 1:
The patent replaces direct mechanical contact (touchscreen interaction) with optical sensing. Light emitters and detectors create detection zones above the screen surface, allowing users to interact through gestures in the air without physical contact. This substitution enables contactless operation while using relatively simple optical components and processing logic.
4Ease of manufacture
If rudimentary parking sensors are used for door supervision, then cost is reduced, but detection resolution is insufficient for preventing collisions
Solution Approach 1:
The system uses multiple sensors positioned along the door edge, each providing partial detection coverage of the external environment. By coordinating these sensors and combining their detection data, the system achieves higher effective resolution for detecting objects like curbs and parked cars, enabling reliable collision prevention while keeping individual sensor requirements modest.
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 solution provides a cost-effective and efficient manufacturing process for proximity sensors, enabling accurate gesture detection and contactless user interfaces, which are essential for rugged environments and public terminals, while preventing contamination and improving user experience.
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
each emitter operable when activated to project light beams through the at least one lens along a common projection plane
Implementation Method 4
each detector operable when activated to detect amounts of light arriving through the at least one lens at the detector
Implementation Method 5
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 a structure suspending at least one lens above a circuit board, light emitters operable to project light beams through the lens along a common projection plane, light detectors operable to detect amounts of light arriving through the lens at the detector, wherein an object in the projection plane reflects light from an emitter to one or more of the detectors, and wherein each emitter-detector pair, including one of the emitters and one of the detectors, when synchronously activated, is expected to generate a greater detection signal at the activated detector than the other detectors, were they to be synchronously activated with any of the emitters, when the object is located at a specific 2D location in the projection plane corresponding to the emitter-detector pair, and a processor identifying gestures performed by the object based on amounts of light detected by the detector of each emitter-detector pair.