Optical Polymer Film Casting with Dynamic Mold Gap Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In the production of optical polymer films, existing methods often result in distortions such as wrinkles and uneven thickness due to expansion or contraction of photocurable materials within molds during curing, and misalignment of molds, which can lead to suboptimal performance in variation-sensitive applications like optical imaging systems.

Innovation Solution

A system is developed where molds are precisely controlled to maintain parallelism and adjust for physical changes during curing, using sensors and an actuable stage to ensure consistent gap spacing and orientation, and a pre-wetting process is employed to reduce trapped air and bubbles, ensuring the molds are parallel before curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photocurable material is cured between molds, then polymer film is produced, but the material expands or contracts causing wrinkles and uneven thickness

Engineering Contradiction:
Improvefilm thickness uniformityVSAvoidmaterial volume stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The system dynamically adjusts the gap between molds during the curing process using an actuable stage. The gap is modified in real-time to compensate for material expansion or contraction, ensuring uniform film thickness despite volume changes in the photocurable material.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Sensors continuously monitor the gap between molds and provide feedback to the control system. Based on this feedback, the actuable stage adjusts the mold positioning to maintain optimal spacing throughout curing, preventing wrinkles and thickness variations caused by material volume instability.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If molds are positioned closely for precise film thickness, then manufacturing precision improves, but misalignment causes distortion

Engineering Contradiction:
Improvefilm thickness controlVSAvoidfilm flatness
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The system replaces manual mechanical alignment with an automated actuable stage controlled by sensors and feedback mechanisms. This substitution enables precise positioning and parallelism maintenance that is difficult to achieve through mechanical means alone, reducing distortion while maintaining tight thickness control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If air is trapped between molds during curing, then curing speed is maintained, but bubbles and distortions occur in the film

Engineering Contradiction:
Improvecuring speedVSAvoidfilm quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system performs preliminary actions before curing by using the actuable stage to position molds optimally and ensure proper material distribution. This preliminary positioning prevents air entrapment while maintaining curing speed, as the molds are already correctly positioned when curing begins.

Inventive Principle:
Principle #10Preliminary 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 production of polymer films with reduced distortions and improved consistency, leading to more predictable physical and optical properties, suitable for high-resolution optical imaging applications.

Implementation Method 1

enclosing a photocurable material (e.g., a photopolymer or light-activated resin that hardens when exposed to light) between two molds, and curing the material (e.g., by exposing the material to light)

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3595864B1Optical polymer films and methods for casting the same
Publication Date: 2022.07.27 MOLECULAR IMPRINTS INC
  • EP3595864B1 patent drawingFigure 1
  • EP3595864B1 patent drawingFigure 2A
  • EP3595864B1 patent drawingFigure 2B

AI summary

An example system is configured to photocure a photocurable material to form a polymer film. The system includes a first chuck configured to support a first substantially planar mold, a second chuck configured to support a second substantially planar mold, and an actuable stage coupled to the first chuck and/or the second chuck. The actuable stage is configured to position the first chuck and/or the second chuck so that the first and second molds are separated by a gap. The system also includes a sensor arrangement for obtaining measurement information indicative of a distance between the first and second molds and/or a pressure between the first and second chucks at each of at least three locations. The system also includes a control module configured control the gap between the first and second molds based on the measurement information.