Blazed Concave Grating Segmentation for Groove Profile Precision
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Solution Overview
Problem
The existing replication methods for blazed concave gratings face challenges in precisely controlling the groove profile, leading to reduced diffraction efficiency and limited application due to the geometric constraints of concave substrates, which affects the quality of optical spectrum instruments.
Innovation Solution
The method involves dividing a whole replication grating blank into two identical blocks, replicating them separately, and then splicing them to form a concave grating, using a convex blazed master grating formed through sensitization, holographic exposure, and ion beam etching, with a segmentation sheet made of polyethylene, and ensuring precise alignment and spacing to maintain diffraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a blazed concave grating is pulled along the vertical direction after replication by a convex master grating, then the groove profile can be obtained, but the diffraction efficiency is greatly affected
Solution Approach 1:
The concave grating blank is divided into two separate blocks that are replicated independently from the convex master grating. Each block is then pulled separately along the vertical direction to form the concave groove profile. This segmentation allows each block to be processed independently, avoiding the distortion that occurs when the entire grating is pulled as a single unit, thereby maintaining diffraction efficiency while achieving the required groove profile precision.
2Manufacturing precision
If ion beam etching is used to directly etch a concave grating, then the groove profile can be controlled, but the geometric shape restriction of the concave substrate makes it difficult or impossible
Solution Approach 1:
Instead of directly etching the concave grating substrate (which is difficult due to geometric constraints), the invention uses a convex master grating as a template and replicates the concave grating profile through contact molding. The convex master grating is first fabricated with precise groove profiles using ion beam etching on a flat substrate, then this convex master is used to create the concave grating blanks through replication. This inverted approach (creating convex first, then replicating concave) overcomes the substrate geometric constraint while maintaining groove profile precision.
3Ease of manufacture
If a convex master grating is used to replicate a concave grating, then the manufacturing process is simplified, but the blazed angle causes the diffraction efficiency to be greatly affected
Solution Approach 1:
The concave grating blank is divided into two separate blocks that are replicated independently from the convex master grating. Each block is then pulled separately along the vertical direction to form the concave groove profile. This segmentation allows each block to be processed independently, avoiding the distortion that occurs when the entire grating is pulled as a single unit, thereby maintaining diffraction efficiency while achieving the required groove profile precision.
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 avoids the impact on diffraction efficiency caused by traditional replication methods, allowing for improved precision and quality of blazed concave gratings, enhancing their application in optical spectrum instruments.
Implementation Method 1
the convex blazed master grating substrate is first subjected to holographic exposure, to obtain a convex photoresist mask grating
Implementation Method 2
ion beam etching is conducted on the developed photoresist master grating to obtain the convex blazed master grating
Implementation Method 3
the convex blazed master grating after evaporation is placed on a platform in a drying oven, epoxy resin is poured onto the convex blazed master grating, and the concave grating substrate is pressed thereon
Implementation Method 4
after leveling and bubble removal, the drying oven is heated to a suitable curing temperature, and after the epoxy resin is cured, the master grating is taken out from the drying oven
Data Source
AI summary
A manufacture method for a blazed concave grating is provided, including: replicating a blazed concave grating by means of a replication process, after the replication is completed, conducting heat preservation and cooling, then separating two gratings (G1, G2) by using different pulling manners respectively, and finally splicing the replicated and separated concave grating blanks, to obtain a required blazed concave grating. This manufacture method can solve the problem of a big error in an existing replication method for a blazed concave grating.