Optical Proximity Sensor Two-Dimensional Tracking Accuracy
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Solution Overview
Problem
One-dimensional arrays of proximity sensors are not accurate enough to determine the two-dimensional location of a pointer within a two-dimensional plane.
Innovation Solution
A calibration tool and method for calibrating parameters of a proximity-sensor strip using a reflective object and processor to incrementally move and activate emitter-detector pairs, measuring detections, and calibrating target positions based on maximum detection distances, allowing for accurate calculation of object location in the detection plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a one-dimensional array of proximity sensors is used, then the device complexity is reduced, but the measurement precision of two-dimensional location deteriorates
Solution Approach 1:
The patent applies dimensionality change by using multiple emitter-detector pairs arranged in a one-dimensional array to detect light from different angles and distances. Each pair provides measurement data from a specific spatial orientation, and by combining measurements from multiple pairs, the system reconstructs two-dimensional location information. This transforms a one-dimensional sensor array into a two-dimensional detection capability through angular and distance differentiation.
2Measurement precision
If multiple emitter-detector pairs are activated to improve location accuracy, then the measurement precision improves, but the use of energy increases
Solution Approach 1:
The patent implements periodic action by sequentially activating different emitter-detector pairs rather than keeping all pairs continuously active. The controller activates specific pairs in a time-multiplexed manner, where each pair is activated for a predetermined time period. This periodic activation reduces overall energy consumption while still achieving accurate two-dimensional location determination through the sequential collection of measurement data from multiple pairs.
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 solution significantly improves the accuracy of detecting object locations across a touchscreen, reducing detection errors and enhancing the precision of two-dimensional tracking.
Implementation Method 1
when an object is located at a target position p(E, D) in the detection plane, corresponding to the pair (E, D), then the light emitted by emitter E is scattered by the object and is expected to be maximally detected by detector D
Data Source
AI summary
A proximity sensor including a housing, light emitters mounted in the housing for projecting light out of the housing along a detection plane, light detectors mounted in the housing for detecting amounts of light entering the housing along the detection plane, whereby for each emitter-detector pair (E, D), when an object is located at a target position p(E, D) in the detection plane, corresponding to the pair (E, D), then the light emitted by emitter E is scattered by the object and is expected to be maximally detected by detector D, and a processor to synchronously activate emitter-detector pairs, to read the detected amounts of light from the detectors, and to calculate a location of the object in the detection plane from the detected amounts of light, in accordance with a detection-location relationship that relates detections from emitter-detector pairs to object locations between neighboring target positions in the detection plane.