Elastomeric Molding for Microstructures on Curved Optical Surfaces
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Solution Overview
Problem
Current methods for producing microstructures on curved surfaces of optical components are complex and inefficient, particularly for three-dimensional macro optics, as they require special adaptations of manufacturing systems and cannot achieve the necessary precision and surface quality for optical applications, especially for anti-reflective structures and sub-micrometer scale features.
Innovation Solution
A method involving an elastic carrier film with a removable reinforcing film, where a model object with sub-microstructures is used to create a structured impression film, which is then transferred to an optical workpiece using a curable transfer film, allowing for precise molding and curing of micro-optical structures on curved surfaces without the need for conventional anti-reflective coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lithographic processes are used to produce embossed structures on curved surfaces, then sharp contour transitions and rigid flanks can be achieved, but smooth uniform contour transitions required for certain optical applications cannot be produced
Solution Approach 1:
The patent changes the fundamental parameter of the structuring approach from lithographic (which creates sharp transitions) to molding/embossing with elastomeric stamps (which can create smooth transitions). The elastomeric material properties allow for continuous contour transitions by conforming to the curved substrate surface while maintaining the desired smooth profile.
Solution Approach 2:
The patent uses a master template with the desired smooth contour profile that is copied onto the curved substrate through contact molding. The elastomeric stamp captures the smooth contour from the master and transfers it to the substrate, enabling reproduction of smooth transitions that cannot be achieved through direct lithographic writing.
2Adaptability or versatility
If existing manufacturing facilities are adapted for microstructuring non-planar surfaces, then three-dimensional optical components can be structured, but the process becomes extremely complex and requires novel manufacturing strategies
Solution Approach 1:
The patent introduces an elastomeric stamp as an intermediary element between the master template and the curved substrate. This stamp acts as a flexible mediator that can conform to complex three-dimensional surfaces while carrying the microstructure pattern, thereby simplifying the manufacturing process compared to direct structuring methods.
Solution Approach 2:
The patent employs thin elastomeric films as the stamping medium, which provides the flexibility needed to conform to curved and three-dimensional surfaces. This flexible thin film approach enables structuring of non-planar substrates without requiring complex adapted manufacturing facilities.
3Manufacturing precision
If direct structuring methods such as laser, ion, or electron beam lithography are used on curved surfaces, then microstructures can be produced, but the surface quality and precision required for optical applications are not achieved
Solution Approach 1:
The patent performs preliminary action by creating a master template with the exact desired microstructure profile before transferring it to the substrate. This pre-prepared master ensures that the transferred structures have the required precision and surface quality, while the stamping process itself is efficient and can be performed in a single step without iterative adjustments.
4Manufacturing precision
If conventional manufacturing methods are used for anti-reflective structures, then existing processes can be maintained, but the required smooth contour transitions cannot be produced
Solution Approach 1:
The patent changes the manufacturing parameter from lithographic patterning (which inherently creates sharp edges) to elastomeric molding (which naturally produces smooth transitions). This parameter change enables the production of anti-reflective structures with the required smooth contour transitions while maintaining process simplicity through a single-step molding operation.
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 enables the production of optical components with high precision and consistent quality, achieving true-to-form microstructures on both micrometer and nanometer scales on curved surfaces, suitable for complex optical components like lenses, without the need for additional coatings, facilitating cost-effective and rapid prototyping.
Implementation Method 1
pressing at least one surface section of an optical workpiece to be structured onto the structured molding film coated with the transfer film on the front side of the carrier film to form a structured transfer film; curing the structured transfer film adhering to the at least one surface section of the optical workpiece to form an optical component structured with (sub-)microstructures
Data Source
Figure 1
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Figure 7~7d
AI summary
The invention relates to a method for producing (sub-)microstructures on curved surfaces of an optical component, comprising the following process steps: - providing an elastic carrier film (10) with a removable reinforcing film (15); - providing a model object (30) with a (sub-)microstructure (35); - applying a molding film (20) to the front (11) of the carrier film (10); - molding the (sub-)microstructure (35) of the model object (30) to form a structured molding film (25); - clamping the carrier film (10) coated with the structured molding film (25), together with the reinforcing film (15), in a holding frame (45); - applying a transfer film (50) to the structured molding film (25); - removing the reinforcing film (15) from the back (12) of the carrier film (10);- Pressing an optical workpiece (70) to be structured onto the structured impression film (25) coated with the transfer film (50) to form a structured transfer film (55); - Curing of the structured transfer film (55) adhering to the workpiece (70) to form an optical component (75) structured with (sub-)microstructures (35); - Removing the structured optical component (75) from the impression film (25).;