Waveguide Film Curing with Dynamic Mold Gap Control
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Solution Overview
Problem
Existing methods for producing optical polymer films suffer from distortions due to internal stresses during the polymerization process, leading to inconsistent film thickness and quality, which affects the performance of optical imaging systems.
Innovation Solution
A method involving the controlled variation of mold separation and radiation intensity during the curing process to regulate stress distribution in photocurable materials, using closed-loop and open-loop control systems, and oscillatory movements to maintain consistent film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If photocurable material is cured by exposing to light and/or heat, then the material hardens and forms a solid film, but internal stresses build up causing film distortion and thickness variation
Solution Approach 1:
The mold structure is designed to dynamically adjust its configuration during the curing process. The mold includes a first portion and a second portion that can move relative to each other, allowing the system to adapt to volume changes in the photocurable material as it cures, thereby preventing stress buildup and maintaining film thickness consistency.
Solution Approach 2:
The system changes physical parameters during the curing process by controlling the separation distance between mold portions and adjusting irradiation intensity. These parameter changes allow the mold to compensate for material shrinkage and stress development, ensuring uniform film thickness while maintaining structural integrity.
2Strength
If monomers polymerize into longer chains during curing, then the material hardens, but the material reduces in volume causing shrinkage and internal stresses
Solution Approach 1:
The mold structure dynamically adjusts the separation between its portions during curing to accommodate volume reduction. As the photocurable material polymerizes and shrinks, the mold portions move closer together, preventing the formation of voids and maintaining uniform film thickness despite the volume change.
Solution Approach 2:
The mold is pre-configured with adjustable portions that can respond to volume changes before final film formation. This preliminary design allows the system to anticipate and compensate for shrinkage, ensuring the final film has the desired volume and thickness without internal stresses.
3Strength
If the photocurable material is enclosed between two molds and cured, then a solid film is formed, but the film becomes distorted due to stress release upon extraction
Solution Approach 1:
The mold portions are designed to move dynamically during and after curing. The ability to adjust the separation between mold portions allows the system to manage stress release gradually, preventing sudden deformation when the film is extracted while maintaining its solid structure.
Solution Approach 2:
The adjustable mold structure provides a cushioning mechanism that absorbs and distributes stress during the extraction process. By controlling the separation and movement of mold portions, the system prevents stress concentration that would otherwise cause film distortion, ensuring the film maintains its intended shape and dimensions.
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
The method produces polymer films with predictable physical and optical properties, reducing wrinkles and uneven thicknesses, resulting in sharper and higher resolution images for optical imaging systems.
Implementation Method 1
irradiating the photocurable material in the space with radiation suitable for photocuring the photocurable material
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
In an example method of forming a waveguide film, a photocurable material is dispensed into a space between a first mold portion and a second mold portion opposite the first mold portion. Further, a relative separation between a surface of the first mold portion with respect to a surface of the second mold portion opposing the surface of the first mold portion is adjusted. The photocurable material in the space is irradiated with radiation suitable for photocuring the photocurable material to form a cured waveguide film. Concurrent to irradiating the photocurable material, the relative separation between the surface of the first mold portion and the surface of the second mold portion is varied and/or an intensity of the radiation irradiating the photocurable material is varied.