Optical Proximity Sensing With Ambient and Interference Light Compensation
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Solution Overview
Problem
Optical proximity sensors face interference from ambient light and specular reflections, which reduce their capability to detect object proximity and motion, and conventional solutions like opaque light barriers increase complexity and cost while being imperfect.
Innovation Solution
The optical sensor employs a system with separate analog-to-digital converters for ambient light, interference light, and proximity detection, using different drive levels for the light source and compensation mechanisms to subtract out interference, allowing for improved detection range and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an opaque light barrier is used to optically isolate the light source from the light detector, then light leakage is reduced, but device complexity, cost and size increase
Solution Approach 1:
The patent extracts and removes the opaque light barrier from the optical sensor design. Instead of using a physical barrier to block light leakage, the invention relies on temporal separation of light source activation and detection, combined with ambient light compensation algorithms, to eliminate the need for the barrier structure entirely.
Solution Approach 2:
The patent replaces the mechanical/optical light barrier structure with an electronic/software-based solution. The system uses controlled timing sequences and digital signal processing to compensate for ambient light and prevent light leakage effects, substituting physical isolation with electronic compensation methods.
2Object-affected harmful factors
If an opaque light barrier is used to optically isolate the light source from the light detector, then light leakage is reduced, but manufacturing cost increases
Solution Approach 1:
The patent extracts and removes the opaque light barrier from the optical sensor design. Instead of using a physical barrier to block light leakage, the invention relies on temporal separation of light source activation and detection, combined with ambient light compensation algorithms, to eliminate the need for the barrier structure entirely.
Solution Approach 2:
The patent replaces expensive opaque light barrier components with cheaper electronic control and processing elements. The solution uses standard LED drivers, timing controllers, and digital signal processing that are more cost-effective than precision optical barriers, particularly in mass-produced consumer electronics.
3Measurement precision
If ambient light compensation is implemented, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements preliminary measurement of ambient light conditions before the actual proximity detection takes place. The system performs ambient light compensation measurements in advance and uses these readings to correct the subsequent detection signals, improving accuracy without requiring complex real-time processing during the critical detection moment.
Solution Approach 2:
The patent uses periodic measurement cycles where the light source is activated in controlled intervals to separately measure ambient light levels and reflected light from objects. By alternating between ambient light measurement modes and object detection modes, the system achieves accurate compensation while maintaining manageable device complexity through time-division multiplexing.
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 enhances the detection range and accuracy of optical sensors by effectively compensating for ambient light and interference, potentially eliminating the need for opaque light barriers and reducing the adverse effects of specular reflections.
Implementation Method 1
the magnitude of light originating from the light source that is reflected from an object and detected by the light detector
Implementation Method 2
a light detector and are typically for use with a light source
Data Source
AI summary
Certain embodiments described herein relate to optical sensors including a light detector and including and/or for use with a light source, and methods for use with such optical sensors. Certain embodiments involve detecting an amount of ambient light that is incident on the light detector and producing ambient light detection data indicative thereof. Additionally, such embodiments involve detecting interference light and producing interference light detection data indicative thereof. Further, such embodiments can involve producing an ambient light compensation signal based on the ambient light detection data, producing an interference light compensation signal based on the interference light detection data, and detecting light of interest that is incident on the light detector and outputting proximity detection data indicative thereof. The light of interest is caused by light that reflects off an object that is external to the optical sensor and is within a sense region of the optical sensor.