Plastic Lens Peripheral Structure for Demolding and Assembly Accuracy

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Solution Overview

Problem

The challenge in the field of optical imaging modules for portable electronic devices is the need for higher quality plastic lens elements that enhance molding yield and reduce demolding resistance and assembling tolerance.

Innovation Solution

The plastic lens element design includes a peripheral region with features such as protrusive structures, indented shapes, and conical surfaces that provide controlled demolding resistance, reduce stress concentration, and enhance assembling accuracy, while maintaining a specific ratio of lens thickness to outer diameter for improved optical imaging quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the plastic lens element uses a conventional molding structure, then the manufacturing process is simple, but the molding yield is low due to high demolding resistance and stress concentration

Engineering Contradiction:
Improvemolding yieldVSAvoidmolding process complexity
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The lens peripheral region is divided into multiple functional zones: a first peripheral region with a draft angle for demolding, and a second peripheral region with reinforcement structures. This segmentation allows each region to perform its specific function optimally, reducing overall demolding resistance while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the lens are given different structural properties: the first peripheral region has a draft angle for easy demolding, while the second peripheral region has increased thickness and reinforcement structures for stress resistance. This local differentiation resolves the contradiction between ease of demolding and structural strength.

Inventive Principle:
Principle #3Local quality

2Length of moving object

If the lens peripheral region is thin-walled, then the lens is lightweight and compact, but the assembling tolerance increases and structural strength decreases

Engineering Contradiction:
Improvelens compactnessVSAvoidassembling tolerance
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The lens design implements local quality by maintaining thin walls in the optical region for compactness while providing localized reinforcement in the second peripheral region. This reinforcement zone with increased thickness and structural features improves assembling tolerance without compromising the overall compact design.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The draft angle in the first peripheral region performs preliminary action by facilitating easier ejection from the mold during manufacturing. This preliminary ease of removal prevents stress concentration that would otherwise affect the precision of the final assembled product.

Inventive Principle:
Principle #10Preliminary action

3Strength

If the lens has a large peripheral region, then the structural strength is high, but the light gathering ability decreases due to reduced optical effective region

Engineering Contradiction:
Improvelens structural strengthVSAvoidlight gathering ability
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The peripheral region is segmented into two distinct zones: the first peripheral region provides structural support with a draft angle, and the second peripheral region provides additional reinforcement. This segmentation allows the lens to achieve high structural strength without excessively enlarging the overall peripheral region, thereby preserving the optical effective region for light gathering.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Structural reinforcement is applied locally in the second peripheral region rather than uniformly across the entire periphery. This localized approach provides the necessary structural strength while minimizing the encroachment on the optical effective region, thus maintaining light gathering ability.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4417405B1Plastic lens element, optical imaging module and electronic device
Publication Date: 2025.10.01 LARGAN PRECISION
  • EP4417405B1 patent drawingFigure 1A
  • EP4417405B1 patent drawingFigure 1B
  • EP4417405B1 patent drawingFigure 1C

AI summary

A plastic lens element includes an optical effective region and a peripheral region. The peripheral region is circularly disposed on a periphery of the optical effective region, and the peripheral region includes a protrusive structure, an indented shape and a drafting part. The protrusive structure is disposed on an outer diameter surface and adjacent to an annular lateral surface. The indented shape is dented from the outer diameter surface towards the optical effective region. The drafting part is raised from a base surface towards the direction away from an optical axis, and the drafting part has a top surface and a bottom surface via the section, wherein the top surface and the bottom surface are arranged along an extending direction parallel to the optical axis, and a conical surface is located between the top surface and the bottom surface.