Optical Sensor Land Overlap Shielding for Stray Light Control
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Solution Overview
Problem
Existing optical sensors face issues with stray light entering the light receiving element due to gaps in substrate coverage by black resist or light shielding coatings, leading to reduced detection accuracy and potential mounting defects.
Innovation Solution
The optical sensor design includes a light shielding region formed by overlapping electrically conductive patterns and a light shielding layer, such as a black silk print, to effectively block stray light while maintaining component mountability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the substrate surface is covered with a black resist or light shielding coating, then stray light prevention is improved, but manufacturing precision deteriorates due to gaps near lands
Solution Approach 1:
The patent combines the light shielding function with the electrically conductive pattern (land) by forming a light shielding layer that overlaps with the land in the normal direction. This merging allows the land to serve dual purposes: electrical connection and stray light shielding, eliminating gaps in coverage while maintaining manufacturing precision.
Solution Approach 2:
The patent creates a composite structure by stacking multiple layers (substrate, electrically conductive pattern, resist, and light shielding layer) to achieve both electrical functionality and optical shielding. The overlapping configuration of the light shielding layer with the land creates a composite region that provides enhanced stray light prevention without compromising manufacturing precision.
2Object-affected harmful factors
If the substrate surface is covered with patterns to reduce stray light, then stray light prevention is improved, but mounting reliability deteriorates due to heat escape
Solution Approach 1:
The patent applies light shielding selectively in specific regions where needed. The light shielding layer overlaps with the land in the normal direction, creating a localized light shielding region that prevents stray light without requiring comprehensive pattern coverage that would interfere with heat dissipation during mounting.
Solution Approach 2:
By merging the light shielding function with the existing land structure through overlapping, the patent avoids creating separate pattern structures that would interfere with thermal management during mounting processes, thereby maintaining mounting reliability.
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 significantly reduces stray light entry, enhancing detection accuracy and preventing mounting defects, thereby improving the overall performance of the optical sensor.
Implementation Method 1
a light shielding layer provided as a layer above the resist; and a light shielding region formed by a portion of the land and a portion of the light shielding layer overlapping in the direction of the normal of a mounting surface of the substrate, thereby the light shielding region configured to shield stray light directed towards the substrate from the light emitting unit
Data Source
AI summary
An optical sensor includes a light emitting unit configured to emit and output light, a light receiving unit configured to receive light, a substrate on which the light emitting unit and the light receiving unit are mounted, an electrically conductive pattern including a land to be electrically connected to an electrode of the light emitting unit, a resist arranged as a layer above the electrically conductive pattern or the substrate, a light shielding layer provided as a layer above the resist, and a light shielding region formed by a portion of the land and a portion of the light shielding layer overlapping in the direction of the normal of a mounting surface of the substrate, to shield stray light directed towards the substrate from the light emitting unit.