Optical Sensor Copper Foil Layout for Stray Light Shielding
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Solution Overview
Problem
Existing methods for reducing stray light in optical sensors, such as covering the substrate surface with black resist or light-shielding coating, are inadequate when unevenness occurs, leading to light transmission and detection accuracy degradation.
Innovation Solution
The optical sensor design includes a housing with specific hole portions and copper foil patterns arranged apart from each other, with a light-shielding member or aperture to shield stray light, ensuring stable light-shielding properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the entire substrate surface is covered with black resist or light-shielding coating solution, then stray light is reduced, but detection accuracy degrades when the coating has unevenness
Solution Approach 1:
The patent divides the substrate surface into multiple regions: a first region with a first copper foil pattern, a second region with a second copper foil pattern, and a third region without copper foil pattern. This segmentation allows different areas to serve different functions - the copper foil patterns provide light shielding in critical areas while leaving other areas open for proper optical function, thus reducing stray light without compromising detection accuracy
Solution Approach 2:
The patent applies light-shielding copper foil patterns selectively in specific regions (first and second regions) rather than covering the entire substrate surface. The copper foil patterns are positioned to shield light in areas where stray light would interfere with detection, while maintaining optical transparency in the third region where detection occurs. This localized approach provides effective stray light reduction while preserving detection accuracy
2Object-affected harmful factors
If black resist or light-shielding coating solution is applied to shield stray light, then light shielding is achieved, but manufacturing complexity increases due to unevenness issues
Solution Approach 1:
The patent uses copper foil patterns that can be easily manufactured and applied to the substrate. These copper foil elements provide effective light shielding and can be replaced or adjusted if needed, offering a simple and cost-effective solution compared to complex coating processes that require precise control to avoid unevenness
Solution Approach 2:
The patent changes the approach from using coating materials (black resist or light-shielding coating solution) to using metallic copper foil patterns. This parameter change in material selection and structural configuration simplifies manufacturing by using rigid, easy-to-position copper foil elements rather than requiring precise coating application processes
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 design effectively reduces stray light, minimizing wrong detections and enhancing detection accuracy without additional shielding materials.
Implementation Method 1
a light shielding member that is arranged so as to contact the substrate and configured to shield light to the space arranged in at least one of the first region or the second region
Data Source
AI summary
In an optical sensor, a copper foil pattern is arranged on a straight line between a light emitting unit and a light receiving unit on a surface of a substrate, the copper foil pattern is arranged apart from a peripheral copper foil pattern by a space, the space is arranged in each of a first region and a second region, and light to the space arranged in at least one of the first region or the second region is shieled by a light shielding member that is arranged so as to contact the substrate.