Moldless PDMS Lens Fabrication via Gravity

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Solution Overview

Problem

Existing lens fabrication methods are inefficient, leading to material waste and mold-related defects, limiting the production of lenses with varying focal lengths.

Innovation Solution

A moldless lens fabrication technique using polydimethylsiloxane (PDMS) droplets deposited and cured on a horizontal slide, with the slide inverted to utilize gravitational force, allowing for layer-by-layer shaping and focal length adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional lens fabrication methods (soft lithography, chemical processing, injection molding) are used, then lenses can be produced with consistent shape, but significant raw material waste occurs and mold imperfections cause defects

Engineering Contradiction:
Improvelens shape consistencyVSAvoidraw material waste
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The lens fabrication process is divided into discrete sequential steps: forming a support layer, then repeatedly depositing and curing additional PDMS layers. Each layer is added independently and cured in place, eliminating the need for bulk material processing and reducing waste associated with traditional molding methods.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The PDMS material exhibits self-leveling properties when deposited on the curved support layer. The material naturally flows and distributes itself to form uniform layers without requiring additional shaping tools or molds, thereby eliminating mold-related defects and reducing material waste from excessive use.

Inventive Principle:
Principle #25Self-service

2Shape

If molds are used to shape lenses, then lens shape can be controlled, but mold imperfections cause defects and lens shape cannot be altered during manufacturing

Engineering Contradiction:
Improvelens shape controlVSAvoidlens defect rate
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The invention extracts and eliminates the mold component from the lens fabrication process entirely. Instead of using molds to shape lenses, the method uses a curved support layer combined with gravitational force and material self-leveling to form lenses directly, removing the source of mold-related defects.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The lens shape becomes dynamic and adjustable during manufacturing. By controlling the deposition parameters and number of layers added to the support layer, the lens curvature and focal length can be modified in real-time during the fabrication process, allowing optimization without retooling.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If fixed模具 are used for lens production, then manufacturing process is simple, but only lenses of certain focal length can be produced

Engineering Contradiction:
Improvefabrication process simplicityVSAvoidfocal length variation
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The curved support layer serves multiple functions: it provides structural support, defines the initial lens curvature, and enables variation of lens parameters. By adjusting the support layer curvature and deposition conditions, the same fabrication system can produce lenses with different focal lengths and shapes, making the process versatile while remaining simple.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Manufacturing precision

If multiple fabrication steps are used (high temperature injection molding, lapping), then lenses can be produced with precise dimensions, but manufacturing time and complexity increase

Engineering Contradiction:
Improvelens dimensional precisionVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention merges multiple traditional fabrication steps into a single integrated process. The support layer formation and subsequent lens layer deposition are combined in one continuous operation on the same substrate, eliminating separate molding and finishing steps while maintaining dimensional precision through gravitational self-leveling.

Inventive Principle:
Principle #5Merging (Combining)

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 minimizes material waste, reduces defects, and enables the production of lenses with a wide range of focal lengths, improving optical magnification and resolving power.

Implementation Method 1

the slide is then inverted to allow gravitational force to pull the uncured, further PDMS droplet down

Methodology Applied
Scientific EffectGravitational force: Gravitation

Implementation Method 2

The further, inverted PDMS droplet is then cured

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Data Source

PatentEP3100100B1Fabricating lenses using gravity
Publication Date: 2019.06.26 AUSTRALIEN NAT UNIV
  • EP3100100B1 patent drawingFigure 1
  • EP3100100B1 patent drawingFigure 2A~2E
  • EP3100100B1 patent drawingFigure 3A~3D

AI summary

Disclosed is a lens fabrication method (100) which uses a droplet of polydimethylsiloxane (PDMS) solution (210) cured on a slide (214) to form a PDMS support layer (211 ) having a curved surface (211 a). Further PDMS droplet (210) is then deposited on the curved surface (211 a) of the PDMS support layer (211 ); the slide (214) is then inverted to allow gravitational force to pull the uncured, further PDMS solution (210) down. The further PDMS solution (210) on the inverted slide is then cured. Each repetition of depositing, slide-inverting, and curing of the further PDMS droplet (210) adds an additional layer of PDMS, altering the shape and focal-length of the lens.