Waveguide Film Curing with Dynamic Gap and Light Control
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Solution Overview
Problem
Existing methods for producing optical polymer films often result in distortions due to internal stresses during the polymerization process, leading to variations in film thickness and quality, which affect the performance of optical imaging systems.
Innovation Solution
A system and method for producing polymer films by using actuable stages and mold structures to control the gap volume and apply controlled forces and light patterns during the curing process, regulating stress distribution and ensuring consistent thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the photocurable material is cured by exposing to light, then the material hardens and forms a solid film, but internal stresses build up causing the film to thin and become distorted
Solution Approach 1:
The patent applies preliminary action by pre-compression of the photocurable material before irradiation. The mold structures are positioned to apply a controlled compressive force to the material prior to curing, which counteracts the internal stresses that will develop during polymerization. This preliminary mechanical adjustment prevents the film from thinning and distorting during the curing process, maintaining consistent thickness while still achieving complete curing.
Solution Approach 2:
The patent changes the physical parameters of the curing process by varying the irradiation intensity over time rather than using constant intensity. The light source intensity is dynamically adjusted during the curing process to control the rate of polymerization, which regulates the buildup of internal stresses. This parameter change allows the material to cure completely while minimizing distortion and thickness variation.
2Stability of the object's composition
If the photocurable material polymerizes into longer chains, then the material hardens, but the material reduces in volume causing shrinkage and internal stresses
Solution Approach 1:
The patent applies the counterweight principle by introducing a compressive force from the mold structures to counteract the volumetric shrinkage that occurs during polymerization. As the photocurable material polymerizes and contracts, the pre-compression from the mold structures provides an opposing force that maintains the film's original shape and prevents distortion. This counterbalancing action ensures the final film maintains its intended geometry despite the inherent shrinkage of the polymerization process.
Solution Approach 2:
The patent changes the temporal parameters of the curing process by using time-varying irradiation intensity. The light intensity is adjusted during the curing process to control the rate and progression of polymerization, which regulates the shrinkage behavior. This parameter control ensures uniform curing across the material while minimizing abrupt volume changes that would cause stress and shape distortion.
3Manufacturing precision
If the relative separation between mold surfaces is adjusted, then the gap volume is controlled for consistent thickness, but the process complexity increases
Solution Approach 1:
The patent applies dynamics by making the mold structure separation adjustable rather than fixed. The relative separation between the first and second mold surfaces can be dynamically controlled during the curing process to maintain optimal gap volume. This dynamic adjustment capability allows the system to compensate for material shrinkage and maintain consistent film thickness, while the adjustability is integrated into the mold design to manage complexity.
Solution Approach 2:
The patent implements feedback control by monitoring the curing process and adjusting the mold separation accordingly. The system detects changes in the photocurable material's physical state during polymerization and responds by adjusting the relative separation between mold surfaces to maintain consistent gap volume. This feedback mechanism ensures uniform film thickness while the control algorithm manages the complexity of the adjustment process.
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 reduced wrinkles and uneven thickness, resulting in more predictable optical properties 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.