Optical Proximity Sensor Directivity Layout for Compact Ranging
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Solution Overview
Problem
Existing optical proximity sensors require a large space due to the need for light emitting elements to be disposed on both sides of the light receiving element, making it difficult to reduce their size.
Innovation Solution
The optical proximity sensor incorporates a first optical functional portion for light emission and a second optical functional portion for light reception, each with distinct directivity characteristics, allowing them to operate with different angles and share a common axis, enabling distance measurement based on the ratio of light reception levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light emitting elements are disposed on both sides of the light receiving element, then distance measurement capability is improved, but sensor size increases
Solution Approach 1:
The patent combines light emitting and light receiving functions into integrated optical functional portions, where each portion contains both emission and reception capabilities. This merging eliminates the need for separate light emitting elements to be disposed on both sides of the light receiving element, thereby reducing the overall sensor size while maintaining distance measurement capability through the interaction between the two integrated portions.
Solution Approach 2:
The patent utilizes directivity characteristics with specific inclination angles (about 15 degrees) to optimize light paths in three-dimensional space. By controlling the angular distribution of light emission and reception sensitivity, the system achieves effective distance measurement without requiring a large physical footprint, thus resolving the contradiction between measurement capability and sensor size.
2Adaptability or versatility
If light emitting elements are disposed on both sides of the light receiving element, then ranging functionality is achieved, but device complexity increases
Solution Approach 1:
Each optical functional portion is designed to perform multiple functions: light emission, light reception, and distance measurement. The first and second optical functional portions can operate with different directivity characteristics to enable ranging, while also being capable of detecting target objects. This multi-functionality reduces the need for separate dedicated components, thereby reducing device complexity while maintaining ranging functionality.
3Area of stationary object
If optical functional portions are positioned to share a common axis, then sensor size is reduced, but measurement accuracy may be affected by target inclination
Solution Approach 1:
The patent introduces different directivity characteristics to the first and second optical functional portions, where each portion has optimized light emission and reception patterns tailored to its specific positioning. The first portion has a directivity characteristic with a specific inclination angle, while the second portion has a different directivity characteristic. This local optimization compensates for the effects of target inclination and maintains measurement accuracy despite the compact configuration.
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 configuration allows for a reduction in sensor size while maintaining accurate distance measurement, simplifying the ranging algorithm, and reducing the impact of target object inclination on measurement accuracy.
Implementation Method 1
detects, by a light receiving element, light that is radiated from a light emitting element and is reflected by a target object
Data Source
AI summary
An optical proximity sensor includes first and second optical functional portions. The first optical functional portion has a directivity characteristic in which an inclination angle when illuminance or light receiving sensitivity in a direction inclined from a reference direction that provides maximum illuminance or maximum light receiving sensitivity becomes about ½ of the illuminance or the light receiving sensitivity in the reference direction is equal to or smaller than about 15°. The second optical functional portion is operable with each of different two directivity characteristics. The first and second optical functional portions are positioned to enable one of the first and second optical functional portions to receive a portion of light emitted from another of the first and second optical functional portions and that is reflected by a target object located in the reference direction.