Image Sensor Light Guide Partition Wall Leak Light Control
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Solution Overview
Problem
The existing image sensor units face issues with non-uniform light distribution due to leak light from the light guide, leading to inconsistent output when the illuminated object is displaced, particularly when the size and width of the frame are reduced and the distance between the light guide and light condenser is close.
Innovation Solution
The image sensor unit design includes a light guide with a diffusing surface and an abutment surface, where the incident angle of light directly reaching the abutment surface is controlled to be below the critical angle, and the light condenser and partition wall are bonded with adhesive, preventing leak light and ensuring uniform output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If notches are formed on the partition wall for filling adhesive, then the light condenser can be bonded to the image sensor unit, but leak light passes through the notches and reaches the illuminated object causing non-uniform light distribution
Solution Approach 1:
The patent extracts the harmful function (light transmission) from the partition wall by making it light-blocking, while retaining the useful function (adhesive bonding) through separate bonding structures. The partition wall is designed to block light completely, and adhesive bonding is achieved through other means such as bonding surfaces on the light guide or light condenser that do not compromise light blocking.
Solution Approach 2:
The patent introduces an intermediary light-blocking layer or coating on the partition wall surface where adhesive is applied. This intermediary layer prevents light from passing through while allowing the adhesive to bond effectively. The intermediary substance serves as a bridge between the light-blocking requirement and the bonding requirement.
2Volume of moving object
If the frame size and width are reduced to make the image sensor unit more compact, then the distance between light guide and light condenser decreases, but leak light more easily reaches the illuminated object causing output non-uniformity
Solution Approach 1:
The patent converts the potentially harmful leak light into a beneficial controlled light distribution by designing the light guide's abutment surface with specific incident angle characteristics. Light that would otherwise leak harmful stray light is redirected at angles that prevent it from reaching the illuminated object, while still maintaining compact dimensions. The harmful effect of close proximity is transformed into a controlled optical path design.
Solution Approach 2:
The patent changes the optical parameters of the light guide by controlling the incident angles of light at the abutment surface. By ensuring that incident angles are below the critical angle for total internal reflection, the light distribution is controlled to prevent leak light while maintaining compact size. This parameter control (incident angle) allows the system to achieve both compactness and uniformity.
3Ease of manufacture
If the abutment surface of the light guide is exposed without partition wall coverage, then assembly is simpler, but leak light occurs when incident angle is below critical angle causing reduced output similarity
Solution Approach 1:
The patent applies local quality by making the partition wall selectively cover only the critical regions where leak light would occur. Instead of covering the entire abutment surface, the partition wall is positioned to cover specific areas where incident light angles are below the critical angle and would cause harmful leak light. This localized coverage maintains assembly simplicity while ensuring output similarity in the critical regions.
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 suppresses leak light, maintains uniform light distribution, and ensures consistent output even when the illuminated object is displaced, preventing the breakdown of output similarity.
Implementation Method 1
a light diffusing surface that diffuses the light entered from the light incident surface
Implementation Method 2
a light condenser that condenses the light from the illuminated object
Implementation Method 3
the light condenser and the partition wall are bonded by an adhesive
Data Source
AI summary
An image sensor unit includes: a light source; a rod-shaped light guide; a light condenser that condenses light from an illuminated object; and a frame. The frame includes: a light guide housing chamber that houses the light guide; a light condenser housing chamber that houses the light condenser; and a partition wall provided between the light guide housing chamber and the light condenser housing chamber. The light guide includes: a light incident surface that receives light emitted by the light source; a light diffusing surface that diffuses the light entered from the light incident surface; and an abutment surface abutted to one side of the partition wall, which covers at least a part of the abutment surface of the light guide, where an incident angle to the abutment surface of the light directly reaching the abutment surface from the light diffusing surface is smaller than a critical angle.