Lens Holding Ring Segmentation for Insertion Force Reduction
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Solution Overview
Problem
The assemblability of lenses in lens units is compromised due to variations in the inner diameter of lens holding rings during molding, leading to increased force requirements and potential deterioration in lens positioning and optical resolution.
Innovation Solution
A lens unit design featuring a lens holding ring with multiple lens receiving portions at different circumferential positions, a polygonal inner peripheral wall, and a thermal expansion coefficient optimized for the optical axis direction, made from resin containing inorganic fibers, which reduces distortion and improves assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lens is press-fitted to the lens holding ring through complete circumferential contact, then the lens is securely held in position, but the insertion force increases and assemblability deteriorates due to molding variations
Solution Approach 1:
The lens holding ring is designed with multiple lens receiving portions (three or more) formed on its inner peripheral wall at different circumferential positions. These receiving portions segment the contact interface between the lens and lens holding ring, allowing the lens to be held securely at multiple discrete points rather than requiring complete circumferential contact, thereby reducing insertion force while maintaining positioning stability
Solution Approach 2:
The lens receiving portions are formed with specific local geometric features on the inner peripheral wall of the lens holding ring. These localized structures provide precise contact points that accommodate molding variations while ensuring reliable lens positioning, concentrating the holding function at specific locations rather than distributing it uniformly across the entire circumference
2Ease of manufacture
If the lens holding ring is made with standard resin material, then manufacturing is simple, but thermal expansion causes distortion and deteriorates optical resolution in high-temperature environments
Solution Approach 1:
The lens holding ring is made from a composite material comprising resin and inorganic fibers. This composite structure combines the ease of resin manufacturing with the dimensional stability of inorganic fibers, reducing thermal expansion-induced distortion while maintaining manufacturing simplicity and preserving optical resolution in high-temperature environments
Solution Approach 2:
The material composition of the lens holding ring is modified by adding inorganic fibers to the resin matrix. This parameter change in material composition alters the thermal expansion characteristics of the lens holding ring, reducing distortion under temperature variations while maintaining the benefits of resin-based manufacturing
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
The design enhances lens assembly by reducing the contact area and insertion force, maintaining optical resolution, and providing improved mechanical strength and thermal stability, suitable for high-temperature applications like in-vehicle or monitoring lenses.
Implementation Method 1
a thermal expansion coefficient optimized for the optical axis direction, made from resin containing inorganic fibers
Data Source
AI summary
A lens unit 10 includes: a second lens 14 that is received in a lens barrel 18; and a lens holding ring 20 that is formed in a shape of a ring, is fitted into the lens barrel 18, includes lens receiving portions 24AS formed on an inner peripheral surface 24A thereof at three or more different positions in a circumferential direction, and allows the second lens 14 to be fitted into the lens holding ring while the second lens 14 is received by the lens receiving portions 24AS.