Imaging Lens Unit Conical Fitting Slopes Water Absorption
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Solution Overview
Problem
The use of plastic lenses with different water absorption rates in imaging lens units can lead to a decrease in optical performance due to internal stress and changes in lens surface distance or shape.
Innovation Solution
The imaging lens unit incorporates a lens barrel made of a resin material with a higher water absorption rate than the plastic lenses, and the plastic lenses have conical fitting slopes centered on the optical axis, formed outside the optical effective portions, to match optical axes and reduce stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If plastic lenses with different water absorption rates are combined in the fitting structure, then weight reduction and cost reduction are achieved, but internal stress occurs due to water absorption differences causing optical performance degradation
Solution Approach 1:
The patent applies local quality by creating an asymmetric fitting slope configuration where only the low-water-absorption lens has a fitting slope, while the high-water-absorption lens has a flat surface. This localized structural differentiation addresses the water absorption difference between adjacent lenses, preventing internal stress concentration at the fitting interface while maintaining the weight reduction benefits of plastic lenses.
2Ease of manufacture
If plastic lenses with different water absorption rates are combined in the fitting structure, then manufacturing flexibility is improved, but internal stress causes lens surface distance or shape changes
Solution Approach 1:
The patent implements local quality by assigning different surface structures to different lenses based on their water absorption characteristics. The low-water-absorption lens has a fitting slope for precise positioning, while the high-water-absorption lens has a flat surface that avoids constraining stress. This localized differentiation maintains manufacturing precision for lens surface distance and shape while preserving the ease of manufacturing plastic lens assemblies.
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 effectively suppresses the reduction in optical performance even when plastic lenses absorb water, by minimizing internal stress and maintaining the lens surface distance and shape.
Implementation Method 1
The lens barrel is formed of a resin material... At least two adjacent plastic lenses of the plastic lenses have different water absorption rates... the resin material has a higher water absorption rate than the plastic lenses
Data Source
AI summary
Provided is an imaging lens unit that is able to suppress a reduction in optical performance even if plastic lenses absorb water. The imaging lens unit includes a lens barrel formed of a resin material and first to seventh plastic lenses housed in the lens barrel. Among the first to seventh plastic lenses, at least two adjacent plastic lenses have different water absorption rates and have conical fitting slopes that are centered on an optical axis, are formed outside optical effective portions of the adjacent plastic lenses, and are fittable to each other. The fitting slope of a high-water-absorption plastic lens that has a high water absorption rate is formed outside the fitting slope of a low-water-absorption plastic lens that has a low water absorption rate.