3D Printed Lens Smoothing via Photopolymer Membrane

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Solution Overview

Problem

Current methods for manufacturing ophthalmic lenses, such as grinding and polishing, are inefficient and wasteful, and molding becomes impractical due to the vast number of possible lens variations, necessitating a more efficient and sustainable additive process for producing customized lenses with arbitrary optical powers and distributions.

Innovation Solution

A post-processing method using a polymerizable liquid monomer and a partially elastic membrane to smooth stepped lens surfaces produced by additive manufacturing, where the monomer is applied between the lens and the membrane, cured under UV light, and then removed, resulting in a smooth, optical-quality surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If mechanical grinding and polishing is used to produce arbitrary lens surfaces, then manufacturing precision and adaptability are improved, but device complexity, energy consumption, and material waste increase

Engineering Contradiction:

Improvesurface smoothnessVSAvoidmaterial waste

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent replaces the mechanical grinding and polishing system with a photopolymerization-based smoothing system. A liquid monomer is applied to the stepped additive-manufactured lens surface, then cured using UV light to produce a smooth optical surface. This substitution eliminates the need for mechanical contact and material removal, thereby reducing material waste while achieving the required surface smoothness for optical applications.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

Engineering Contradiction:

Improvesurface smoothnessVSAvoidenergy consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces the energy-intensive mechanical grinding and polishing system with a photopolymerization-based smoothing system. The liquid monomer is cured using UV light to produce a smooth optical surface, eliminating the need for continuous mechanical operation and associated energy consumption. This substitution significantly reduces energy usage while achieving the required surface smoothness for optical applications.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If additive manufacturing is used to produce lenses with arbitrary optical powers, then adaptability and productivity are improved, but surface smoothness deteriorates due to stepped layer structure

Engineering Contradiction:

Improveoptical power customizationVSAvoidsurface smoothness

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent introduces a liquid monomer as an intermediary substance between the stepped additive-manufactured lens surface and the final smooth optical surface. The monomer fills the gaps and irregularities of the stepped structure, and when cured, creates a continuous smooth surface that maintains the underlying optical power distribution while eliminating surface roughness. This intermediary approach enables both customization and optical quality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes the phase transition of the liquid monomer from liquid to solid through photopolymerization. The liquid monomer is applied to conform to the stepped surface, then UV light initiates polymerization, transforming it into a solid smooth surface. This phase transition enables the surface smoothing function while preserving the customized optical power distribution of the additive-manufactured lens.

Inventive Principle:

Principle #36Phase transitions

4Productivity

If molding is used to produce lenses, then productivity is improved for high-volume production, but adaptability deteriorates due to the need for numerous different molds

Engineering Contradiction:

Improveproduction volumeVSAvoidlens variation capability

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent makes the additive manufacturing process universal by enabling it to produce any lens prescription and optical power distribution using the same basic equipment and material system. The liquid monomer and photopolymerization process can accommodate arbitrary lens designs, eliminating the need for specialized molds for each lens type. This universal approach maintains productivity while achieving full adaptability for customized lenses.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 method effectively smooths additive lens surfaces, reducing material waste and energy consumption, enabling on-demand lens production with improved optical performance and reduced production costs, while allowing for integration of advanced features like mirrors and diffraction gratings.

Implementation Method 1

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS10086575B2Smoothing of 3D printed lenses

Publication Date: 2018.10.02 INDIZEN OPTICAL TECHNOLOGIES OF AMERICA LLC

AI summary

Systems and methods for smoothing a lens are disclosed herein. A monomer used to make or augment the lens according to an additive method is deposited on the lens surface to be smoothed. A film or membrane with certain elastic properties is pressed against the layered (stepped) surface, with the monomer in between the lens and the membrane. The pressure of the membrane spreads the monomer over the surface of the lens, filling the spaces between the layered (stepped) surface and the membrane. A curing agent is applied to transition the monomer into a polymer coating matching the curve of the membrane. The membrane is removed, leaving a clean, smooth lens surface.