Cemented Lens Flange Projection Centering

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Solution Overview

Problem

In lens units, the adhesive layer of cemented lenses peels easily due to misalignment and expansion, leading to poor optical performance and resolution, as existing techniques struggle to precisely center lenses with a clearance that inhibits peeling while maintaining high resolution.

Innovation Solution

A lens unit design featuring a cemented lens with a convex and concave lens surface connected by an adhesive layer, where a smaller gap between the projection and opposed portion (Gb) is maintained, allowing precise centering and preventing peeling, while an annular adhesive reservoir ensures even adhesive distribution and prevents leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a clearance (adhesive layer) with a certain length or more is provided between connection surfaces to inhibit peeling, then adhesive peeling is inhibited, but lens centering becomes difficult and coma aberration is not completely corrected

Engineering Contradiction:

Improveadhesive layer stabilityVSAvoidlens centering precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The invention divides the flange structure into multiple functional segments: a projection protruding from one flange and an opposed portion on the other flange. This segmentation creates a dedicated centering mechanism (projection-opposed portion interface) that is separate from the adhesive bonding function, allowing precise lens alignment while maintaining adequate adhesive clearance for peeling inhibition.

Inventive Principle:

Principle #1Segmentation

2Reliability

If lenses are connected with an adhesive layer to correct chromatic aberration of magnification, then optical performance is improved, but adhesive peeling occurs due to misalignment and expansion

Engineering Contradiction:

Improveoptical performanceVSAvoidadhesive layer integrity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The projection and opposed portion structure performs preliminary centering action before adhesive bonding. By pre-aligning the lenses through the projection fitting into the opposed portion, the adhesive layer is applied in the correct position, preventing misalignment-induced peeling while maintaining the cemented lens structure needed for chromatic aberration correction.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The projection-opposed portion structure acts as an intermediary mechanism between the two flanges. It provides a mechanical interface that ensures proper alignment and distribution of stress, preventing direct transmission of expansion forces to the adhesive layer and thereby inhibiting peeling while maintaining optical performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Temperature

If one lens element contacts the lens barrel to prevent expansion, then thermal expansion is controlled, but dislocation occurs and adhesive peeling is highly likely

Engineering Contradiction:

Improvethermal expansion controlVSAvoidadhesive layer stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The invention applies local quality by providing thermal expansion control at specific locations through the projection-opposed portion interface, rather than through uniform contact with the lens barrel. The projection fits into the opposed portion with a controlled gap, allowing localized stress management that prevents dislocation and adhesive peeling while still controlling thermal expansion where needed.

Inventive Principle:

Principle #3Local quality

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 inhibits adhesive peeling, allows precise lens centering, and enhances optical performance by maintaining high resolution and preventing issues like diffuse reflection and damage.

Implementation Method 1

a first cemented lens element (20a) and a second cemented lens element (20b) which are connected to the first cemented lens element (20a) via an adhesive layer (29)

Methodology Applied

Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

In a case where environmental temperature rises and the cemented lens elements are expanded, one of the cemented lens elements is in contact with the inner circumferential surface of the lens barrel; therefore, expansion is prevented by the lens barrel. Consequently, expansion and distortion occur.

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS11630286B2Lens unit and cemented lens

Publication Date: 2023.04.18 SANKYO SEIKI MFG CO LTD

AI summary

A cemented lens may include a first lens and a second lens connected via an adhesive layer. The first lens may include a convex surface facing toward the second lens, and a first flange surrounding an outer circumference of the convex surface. The second lens may include a concave surface connected to the convex surface, and a second flange surrounding an outer circumference of the concave surface. One of the first and second flange may include a projection protruding toward an other of the first and second flange. The other of the first and second flange may include an opposed portion opposed to a side surface of the projection Ga is a distance between the convex surface and the concave surface, and Gb is a distance between the side surface and the opposed portion, and the following expression: Gb<Ga may be satisfied.