Asymmetric Optical Proximity Sensing Beyond Surface Reflectivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optoelectronic proximity sensors struggle to accurately measure proximity independent of object surface reflectivity, particularly for objects like fingers, hands, or ears, due to varying skin pigmentation affecting light reflectivity.
Innovation Solution
The implementation of optoelectronic devices with an asymmetric field overlap, utilizing multiple light-emitting and light-sensitive assemblies with distinct pitches and angles, allows for proximity measurements independent of object surface reflectivity by normalizing signal ratios associated with threshold proximity values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single light-emitting assembly and single light-sensitive assembly are used, then the device complexity is low, but the measurement precision is affected by object surface reflectivity
Solution Approach 1:
The patent employs asymmetric field overlap by configuring multiple light-emitting assemblies with different pitch distances to the light-sensitive assembly. Specifically, a first light-emitting assembly is positioned at a first pitch and a second light-emitting assembly at a second pitch, creating asymmetric illumination fields that overlap with the light-sensitive assembly's field of view. This asymmetry enables the system to generate multiple signals with different dependencies on object surface reflectivity, which can then be combined or ratioed to eliminate reflectivity effects and achieve accurate proximity measurements independent of skin pigmentation or surface properties.
2Adaptability or versatility
If multiple light-emitting assemblies with different pitches are used, then proximity measurement becomes independent of surface reflectivity, but the device complexity increases
Solution Approach 1:
The patent makes the light-sensitive assembly serve multiple functions by receiving light from multiple light-emitting assemblies positioned at different pitches. The single light-sensitive assembly processes multiple illumination fields simultaneously, generating multiple signals that encode different geometric relationships with the object. This multi-functionality allows the system to achieve independence from surface reflectivity without proportionally increasing the number of light-sensitive components, thereby managing device complexity while achieving the desired adaptability.
3Measurement precision
If asymmetric field overlap is implemented, then proximity measurement accuracy improves, but the difficulty of detecting and measuring increases
Solution Approach 1:
The patent implements a feedback-based signal processing approach where the processor receives multiple signals from the light-sensitive assembly and iteratively determines object proximity by analyzing signal ratios. The system compares the ratio of signals from different light-emitting assemblies against expected geometric relationships to infer object distance. This feedback mechanism allows the system to handle the complexity of asymmetric field overlap measurements by continuously adjusting and refining proximity estimates based on the observed signal patterns, thereby achieving high measurement precision despite the increased detection complexity.
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 approach enables precise proximity measurement regardless of object surface reflectivity, using the asymmetric field overlap to determine object position based on signal ratios, thus overcoming the limitations of existing sensors.
Implementation Method 1
The first light-sensitive assembly is operable to convert light emitted by the first light-emitting assembly reflected from the object into a first signal. Moreover, the light-sensitive assembly is operable to convert light emitted by the second light-emitting assembly reflected from the object into a second signal.
Implementation Method 2
The light-sensitive assembly is operable to convert light emitted by the first light-emitting assembly reflected from the object into a first signal. Moreover, the light-sensitive assembly is operable to convert light emitted by the second light-emitting assembly reflected from the object into a second signal.
Data Source
AI summary
An optoelectronic device has an asymmetric field overlap and is operable to measure proximity independently of object surface reflectivity. In some instances, the optoelectronic device includes a plurality of light-emitting assemblies and a light-sensitive assembly. In some instances, the optoelectronic devices include a plurality of light-sensitive assemblies and a light-emitting assembly. An asymmetric field overlap is attained in various implementations via various field-of-view axis, field-of-view angle, field-of-illumination axis, field-of-illumination angle, optical element and/or pitch configurations.