Asymmetric Replication Tool for Optical Structures
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Solution Overview
Problem
In micro-optics, there is a challenge in manufacturing optical elements under strong space restrictions, requiring miniaturization and high process stability for efficient mass production, especially when optical elements need to be produced close to each other with asymmetric spatial constraints.
Innovation Solution
A replication tool with different steepnesses in various directions is used to create an optical structure with a strongly asymmetric footprint, ensuring good flow control of replication material and process stability, allowing for high yield production even under limited vertical structuring constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If optical elements are produced close to each other under asymmetric space restrictions, then space utilization is improved, but manufacturing precision deteriorates due to limited space for replication material flow
Solution Approach 1:
The patent applies asymmetry by designing the replication tool with different steepness values in different azimuthal ranges. The first compensation surface has a first steepness in a first azimuthal range, while the second compensation surface has a second steepness in a second azimuthal range. This asymmetric design allows the optical structure to have a tailored footprint that minimizes space in directions where other components are located, while maintaining sufficient space in other directions for proper replication material flow and manufacturing precision.
Solution Approach 2:
The patent implements local quality by varying the steepness of compensation surfaces in different azimuthal ranges. Instead of using a uniform steepness throughout, the replication tool has direction-dependent steepness values that are optimized for local requirements. This allows different regions of the optical structure to have different geometric properties suited to their specific functional and spatial requirements.
2Area of stationary object
If the footprint of optical structure is minimized in one direction, then space restrictions are satisfied, but void formation risk increases due to insufficient replication material
Solution Approach 1:
The patent resolves this contradiction through asymmetric compensation surfaces with direction-dependent steepness. In azimuthal ranges where the footprint is minimized, the compensation surfaces are designed with appropriate steepness values that still ensure sufficient replication material presence. The asymmetry allows the structure to be compact in directions where space is constrained while maintaining adequate material flow paths in directions where void formation is a risk.
Solution Approach 2:
The patent changes geometric parameters (steepness values of compensation surfaces) based on azimuthal direction to balance footprint minimization with void prevention. By adjusting the steepness parameter locally in different azimuthal ranges, the replication process can achieve compact footprints while maintaining sufficient material flow and pressure distribution to prevent void formation.
3Manufacturing precision
If replication material is dispensed with limited precision, then excess replication material is used to compensate, but this increases the footprint of the optical structure
Solution Approach 1:
The patent uses asymmetric compensation surfaces to efficiently manage excess replication material. The different steepness values in different azimuthal ranges guide the excess material to specific regions where it can be accommodated without significantly increasing the overall footprint. This asymmetric geometry optimizes the distribution and containment of excess material that results from limited dispensing precision.
Solution Approach 2:
The patent converts the harmful effect of excess replication material (caused by limited dispensing precision) into a beneficial outcome. By designing compensation surfaces with specific asymmetric steepness values, the excess material is directed to form part of the surrounding portion that laterally surrounds the optical element, rather than causing defects or requiring additional processing steps.
4Ease of manufacture
If conventional replication tools with uniform steepness are used, then manufacturing is simpler, but asymmetric footprint control is not achieved
Solution Approach 1:
The patent deliberately introduces asymmetry into the replication tool design by providing compensation surfaces with different steepness values in different azimuthal ranges. This asymmetric design enables precise control over the footprint shape of the produced optical structures, allowing them to be tailored to specific asymmetric space restrictions while maintaining manufacturability through a systematic approach.
Solution Approach 2:
The patent implements local quality by varying the steepness of compensation surfaces in different azimuthal ranges around the central axis. This allows different angular regions of the replication tool to have optimized geometric properties that collectively produce the desired asymmetric footprint while maintaining overall manufacturing feasibility.
Data Source
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AI summary
A replication tool (10) for producing an optical structure comprising an optical element, is described. It comprises - a central section (c) having the shape defining a negative of a portion of the optical structure and a vertically aligned central axis (A); - a surrounding section (s) laterally surrounding the central section (c); and - one or more contact standoffs (15) defining a plane referred to as contact plane (5a). In a first azimuthal range, the surrounding portion provides a first compensation surface (f1) facing away from the central axis (A), and in a second azimuthal range, the surrounding portion provides a second compensation surface (f1) facing away from the central axis (A). In any cross-section containing the central axis (A) in the second azimuthal range, a steepness of the second compensation surface (f2) is higher than a steepness of the first compensation surface (f1) in any cross-section containing the central axis (A) in the first azimuthal range. Corresponding optical devices and also a corresponding method for manufacturing an optical structure using the replication tool20 (10) are described, too. The invention can be used for achieving a locally reduced footprint of the optical structure on a substrate (5) in wafer-level mass production.