Thermoset Lens Casting With Injection-Molded Surface Microstructures

Solution Overview

Problem

The high cost and technical infeasibility of creating glass or nickel molds with precise microlenses for casting thermoset lenses, which are necessary to slow myopia progression, hinder widespread accessibility of these lenses.

Innovation Solution

Using thermoplastic injection molding to create molds with integrated microstructures, followed by thermoset casting to replicate these structures onto lenses, allowing for cost-effective production of thermoset lenses with surface microlenses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If glass or nickel molds with precise microlenses are used for casting thermoset lenses, then the lens manufacturing precision is improved, but the device complexity and manufacturing cost increase significantly

Engineering Contradiction:

Improvemicrolens precisionVSAvoidmold complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses a master mold with microlenses to create a replication mold. The master mold is first created with precise microlenses, then used to cast a replication mold that copies the microlens pattern. This replication mold can be used multiple times without requiring the original master mold to be reused, thereby reducing the complexity of maintaining precise master molds while achieving the required lens manufacturing precision.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent employs disposable plastic molds instead of expensive, durable glass or nickel molds. These plastic molds are sufficiently precise for the application and can be discarded after use, eliminating the need for costly maintenance, cleaning, and preservation of complex glass or nickel mold structures. This approach reduces device complexity while maintaining adequate manufacturing precision.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If glass or nickel molds with precise microlenses are used for casting thermoset lenses, then the lens manufacturing precision is improved, but the manufacturing cost increases significantly

Engineering Contradiction:

Improvemicrolens precisionVSAvoidmold manufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent uses a master mold with microlenses to create a replication mold. The master mold is first created with precise microlenses, then used to cast a replication mold that copies the microlens pattern. This replication mold can be used multiple times without requiring the original master mold to be reused, thereby reducing the complexity of maintaining precise master molds while achieving the required lens manufacturing precision.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent employs disposable plastic molds instead of expensive, durable glass or nickel molds. These plastic molds are sufficiently precise for the application and can be discarded after use, eliminating the need for costly maintenance, cleaning, and preservation of complex glass or nickel mold structures. This approach reduces device complexity while maintaining adequate manufacturing precision.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Manufacturing precision

If traditional glass or nickel molds are used for casting thermoset lenses with microlenses, then the lens quality is improved, but the productivity decreases due to higher production costs and complexity

Engineering Contradiction:

Improvelens qualityVSAvoidproduction efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent employs disposable plastic molds instead of expensive, durable glass or nickel molds. These plastic molds are sufficiently precise for the application and can be discarded after use, eliminating the need for costly maintenance, cleaning, and preservation of complex glass or nickel mold structures. This approach reduces device complexity while maintaining adequate manufacturing precision.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the material parameter of the mold from traditional glass or nickel to thermoplastic material. This material change enables the use of injection molding techniques to create molds with integrated microlens structures, significantly improving production efficiency and scalability while maintaining the required lens quality through precise mold design.

Inventive Principle:

Principle #35Parameter changes

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

Enables mass production of thermoset lenses with surface microstructures at a lower cost than traditional methods, making them more accessible and effective in managing myopia progression.

Implementation Method 1

fabricating a thermoplastic mold element by thermoplastic injection molding

Methodology Applied

Scientific EffectInjection molding:

Implementation Method 2

casting a lens by a thermoset casting technique

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS20250276501A1Casting a lens with surface microstructures

Publication Date: 2025.09.04 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)

AI summary

A mold element (350) is fabricated (305, 310, 315) using a first mold (5) with which microstructures (323) are integrally formed in relief on the mold element (350). A lens (340) is cast (320, 325, 330, 335) using a second mold (7) that includes the mold element (350) such that the microstructures (337) are integrally formed on the lens (340).