Laminated Diffractive Optical Element for Stress-Stable Chromatic Correction
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Solution Overview
Problem
Existing optical systems suffer from chromatic aberrations and diffraction efficiency due to residual stress and refractive index variations in the diffraction grating shape, resulting in de-focusing state, ring variations in the diffraction grating shape, and the concentration of the optical element 100 are reduced.
Innovation Solution
A lamination type optical element is designed with a first optical layer and a second optical layer, where the refractive index of the second optical layer is higher than the first, and the Abbe number of the second is also higher, with the second layer having a modulus of elasticity between 0.1 GPa and 3.0 GPa, reducing refractive index variations and phase differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-refractive-index and low-dispersion material with inorganic fine particles is used to reduce chromatic aberration, then chromatic aberration is improved, but residual stress increases due to high modulus of elasticity causing refractive index variations
Solution Approach 1:
The patent changes the modulus of elasticity parameter of the second optical layer to a specific range (0.1-3.0 GPa) to reduce residual stress while maintaining chromatic aberration correction. This parameter optimization resolves the contradiction by finding the optimal elasticity value that balances stress reduction with optical performance.
Solution Approach 2:
The patent uses composite materials in both optical layers - the first layer contains inorganic fine particles (such as zirconia or ITO) dispersed in organic resin, and the second layer uses resin compositions with controlled elasticity. These composite structures enable simultaneous achievement of chromatic aberration correction and stress reduction.
2Power
If the surface has a diffraction grating shape to improve diffraction efficiency, then diffraction efficiency is improved, but non-uniform film thickness generates gaps and residual stress
Solution Approach 1:
The patent optimizes the modulus of elasticity parameter of the second optical layer to compensate for the non-uniform film thickness caused by the diffraction grating structure. By controlling the elasticity within 0.1-3.0 GPa, the material can better accommodate thickness variations without generating excessive residual stress.
Solution Approach 2:
The patent applies different material properties to different regions - the first optical layer has high refractive index and low dispersion for chromatic aberration correction, while the second optical layer has controlled elasticity to handle stress from the diffraction grating structure. This local differentiation resolves the contradiction between diffraction efficiency and thickness uniformity.
3Quantity of substance
If inorganic fine particles are dispersed in organic resin to achieve high refractive index, then refractive index is improved, but modulus of elasticity increases causing excessive residual stress
Solution Approach 1:
The patent changes the modulus of elasticity parameter to a specific range (0.1-3.0 GPa) to reduce residual stress while maintaining high refractive index through inorganic particle dispersion. This parameter optimization allows the system to achieve high refractive index without excessive stress.
Solution Approach 2:
The patent uses composite materials where inorganic fine particles (zirconia, ITO) are dispersed in organic resin to achieve high refractive index, and combines this with a second layer of resin composition having controlled elasticity. This composite approach enables simultaneous achievement of high refractive index and low residual stress.
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 solution effectively reduces residual stress and refractive index variations, enhancing the diffraction efficiency and reducing phase differences, leading to improved optical performance.
Implementation Method 1
the second optical layer is composed of a second resin having a modulus of elasticity of 0.1 GPa or more and 3.0 GPa or less at 22° C. or higher and 24° C. or lower
Implementation Method 2
a diffraction grating being disposed at the interface between the first optical layer and the second optical layer
Implementation Method 3
the refractive index of the d-line of the second optical layer is higher than the refractive index of the d-line of the first optical layer, the Abbe number of the second optical layer is higher than the Abbe number of the first optical layer
Data Source
AI summary
An optical element including a first optical layer, a second optical layer, and a transparent base material, the first optical layer being disposed between the second optical layer and the transparent base material and a diffraction grating being disposed at the interface between the first optical layer and the second optical layer, wherein the refractive index of the d-line of the second optical layer is higher than the refractive index of the d-line of the first optical layer, the Abbe number of the second optical layer is higher than the Abbe number of the first optical layer, the first optical layer is composed of a first resin and inorganic particles dispersed in the first optical layer, and the second optical layer is composed of a second resin having a modulus of elasticity of 0.1 GPa or more and 3.0 GPa or less at 22° C. or higher and 24° C. or lower.