Diffraction Optical Element Alignment Using Center Marker
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Solution Overview
Problem
Diffraction optical elements exhibit reduced diffraction efficiency for wavelengths other than the specific wavelength they are designed for, limiting their application in optical systems using white light, and existing alignment methods are prone to recognition errors due to curvature-dependent reflection changes.
Innovation Solution
A method for producing a diffraction optical element involving a substrate with a diffraction grating configuration and an optical adjusting layer formed using a mold with a marker, where the center alignment is achieved by matching the marker with the diffraction grating's center, allowing for precise positioning and formation of the optical adjusting layer, which reduces wavelength dependence and decentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diffraction optical element is designed to have optimum diffraction efficiency for light of a specific wavelength, then the diffraction efficiency is improved for that wavelength, but the diffraction efficiency is decreased for light of other wavelengths
Solution Approach 1:
The patent uses a composite structure consisting of a glass substrate with a diffraction grating and an ultraviolet-curable resin layer. This composite material approach allows the system to achieve high diffraction efficiency at the design wavelength while maintaining acceptable performance across other wavelengths, thereby reducing wavelength dependence and improving adaptability.
Solution Approach 2:
The patent adjusts the thickness of the ultraviolet-curable resin layer (set to 10 μm or less) to optimize the optical characteristics. By controlling this parameter, the patent achieves a balance between diffraction efficiency at the design wavelength and performance across other wavelengths, reducing the wavelength dependence issue.
2Adaptability or versatility
If the second optical material is caused to cover and adhere to the first optical material, then the wavelength dependence of diffraction efficiency is decreased, but the production complexity and alignment precision requirements increase
Solution Approach 1:
The patent incorporates a marker on the glass substrate before applying the ultraviolet-curable resin layer. This preliminary action enables precise positioning and alignment during the molding process, simplifying the overall production complexity while maintaining the wavelength independence benefit.
Solution Approach 2:
The marker acts as an intermediary element that facilitates precise alignment between the glass substrate and the molding process. This intermediary feature simplifies the alignment process and reduces the complexity of ensuring precise coverage of the diffraction grating by the resin layer.
3Manufacturing precision
If the thickness of the second optical material is increased to cover the diffraction grating, then the alignment precision is improved, but the optical characteristics are significantly changed by small positional deviations
Solution Approach 1:
The marker is positioned in advance on the glass substrate to guide precise alignment during the molding process. This preliminary positioning action ensures accurate alignment without requiring excessive thickness of the resin layer, thereby maintaining optical characteristics stability while achieving sufficient alignment precision.
4Manufacturing precision
If a marker is formed at the center of the lens substrate for position alignment, then the alignment precision is improved, but recognition errors occur due to curvature-dependent reflection changes
Solution Approach 1:
The marker serves as an intermediary reference feature that is independently positioned on the glass substrate. This intermediary marker provides a stable reference for alignment that is not affected by the curvature-dependent reflection changes, thereby maintaining both alignment precision and recognition accuracy.
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 provides high-precision alignment and optical characteristics, enabling diffraction optical elements with improved performance across various wavelengths and reducing production complexity.
Implementation Method 1
A diffraction optical element has a grating configuration with a great number of grooves formed at a surface of a substrate
Implementation Method 2
as opposed to refraction, diffraction of light is expressed to a higher degree as the light has a longer wavelength
Data Source
AI summary
According to a method for producing a diffraction optical element, the center of a molding face and the center of a substrate are positionally aligned to each other based on a marker of a prescribed shape which is formed at the center of the molding face of a mold and the shape of a diffraction grating of the substrate. A nanocomposite material is located between the molding face and the diffraction grating, and the material is pressed by the mold and the substrate to form an optical adjusting layer on the diffraction grating.