Plastic Lens Holder With Non-Uniform Bite For Molding Accuracy

Solution Overview

Problem

The existing methods for manufacturing plastic lenses with holders, such as those used in digital single lens reflex cameras, face challenges in achieving stable surface accuracy and quality due to deformation of the holder under pressure and heat during the molding process, leading to inconsistent product accuracy and increased costs from adhesive bonding processes.

Innovation Solution

The method involves forming a plastic lens with a holder where the holder bites into the side surface, with a gate trace, and the bite amount closest to the gate is smaller than the average bite amount, allowing the lens to be molded without adhesives and maintaining high accuracy by controlling the holder's protrusion into the mold cavity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the holder is inserted into the mold with a uniform protrusion amount, then the lens can be molded with adequate fixing, but the holder deforms under pressure and heat causing unstable surface accuracy

Engineering Contradiction:

Improvesurface accuracy of the lensVSAvoidshape stability of the holder

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The holder is designed with non-uniform protrusion amounts at different locations. Specifically, the protrusion amount at the gate side is smaller than the average protrusion amount, creating local variation in the holder's geometry. This local quality difference allows the gate side to resist deformation better during molding while maintaining adequate fixing elsewhere.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The holder design preemptively counteracts the deformation caused by pressure and heat by creating a smaller protrusion amount at the gate side before molding begins. This preliminary structural adjustment prevents the gate side from deforming under molding conditions, thereby stabilizing the lens surface accuracy.

Inventive Principle:

Principle #9Preliminary anti-action

2Strength

If adhesive bonding is used to fix the lens in the holder, then the lens can be securely integrated, but the manufacturing cost increases

Engineering Contradiction:

Improvebonding strength between lens and holderVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates the adhesive bonding process from the manufacturing sequence. By designing the holder with a specific undercut shape and non-uniform protrusion, the lens is fixed directly through mechanical interference during injection molding, removing the need for separate adhesive application steps and reducing manufacturing cost.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The fixing function and the molding process are merged into a single operation. The holder's undercut shape and protrusion design enable the lens to be fixed to the holder automatically during the injection molding process itself, combining the fixing and molding operations into one step, thereby eliminating the need for separate adhesive bonding.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of manufacture

If an undercut shape is formed in the holder for fixing the lens, then adhesive bonding can be eliminated, but the holder deforms under pressure and heat during molding

Engineering Contradiction:

Improveelimination of adhesive bonding processVSAvoidaccuracy of the molded product

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The holder is designed with non-uniform protrusion amounts at different locations. Specifically, the protrusion amount at the gate side is smaller than the average protrusion amount, creating local variation in the holder's geometry. This local quality difference allows the gate side to resist deformation better during molding while maintaining adequate fixing elsewhere.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The holder design preemptively counteracts the deformation caused by pressure and heat by creating a smaller protrusion amount at the gate side before molding begins. This preliminary structural adjustment prevents the gate side from deforming under molding conditions, thereby stabilizing the lens surface accuracy.

Inventive Principle:

Principle #9Preliminary anti-action

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 approach enables the integration of a holder and lens at a low cost with high accuracy, reducing deformation and variations in the molded product, resulting in improved surface accuracy and quality.

Implementation Method 1

injecting molten resin from a gate into a cavity; and molding a lens

Methodology Applied

Scientific EffectPhase change (molten resin to solid lens): Phase Change

Implementation Method 2

the plastic lens is fixed by the holder biting into the side surface

Methodology Applied

Scientific EffectMechanical interference (biting): Mechanical Force

Data Source

PatentUS10527813B2Optical part and method for manufacturing optical part

Publication Date: 2020.01.07 CANON KK

AI summary

A plastic lens is fixed by a holder biting into the plastic lens, a side surface of the plastic lens has a gate trace, and a bite amount into the plastic lens of the holder closest to the gate trace is smaller than an average bite amount into the plastic lens of the holder.