Optical System Diffractive Element Crystalline Glass Aberration Control
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Solution Overview
Problem
Existing optical systems, particularly those utilizing diffractive optical elements, face challenges in achieving improved optical performance, including excessive correction of axial and lateral second-order chromatic aberrations, curvature of field, and coma aberrations, which affect imaging quality.
Innovation Solution
The optical system incorporates a diffractive optical element and at least one lens made of crystalline glass, with specific configurations and conditional expressions to optimize the partial dispersion ratio, refractive index, and Abbe number of the glass material, ensuring satisfactory correction of spherical and chromatic aberrations, and includes a vibration-proof lens for image stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a diffractive optical element is used to downsize the optical system, then the optical system size is reduced, but axial and lateral second-order chromatic aberrations are excessively corrected
Solution Approach 1:
The patent changes the material parameter (using crystalline glass with specific partial dispersion ratio and Abbe number) to adjust the chromatic aberration correction. By selecting crystalline glass with a partial dispersion ratio θgF within 0.640-0.680 and Abbe number νd within 65.0-75.0, the excessive correction of second-order chromatic aberration is controlled while maintaining the downsized structure with diffractive optical element.
2Volume of moving object
If a diffractive optical element is used to downsize the optical system, then the optical system size is reduced, but curvature of field and coma aberrations are excessively corrected
Solution Approach 1:
The patent changes the material parameter (using crystalline glass with specific partial dispersion ratio and Abbe number) to adjust the chromatic aberration correction. By selecting crystalline glass with a partial dispersion ratio θgF within 0.640-0.680 and Abbe number νd within 65.0-75.0, the excessive correction of second-order chromatic aberration is controlled while maintaining the downsized structure with diffractive optical element.
3Manufacturing precision
If lenses with specific glass materials are used to correct aberrations, then optical performance is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by selecting specific crystalline glass materials for particular lenses (positive lenses with specific focal lengths) rather than uniform material selection. The first positive lens has a partial dispersion ratio θgF1 and Abbe number νd1 within specific ranges, while the second positive lens has θgF2 and νd2 within different ranges, optimizing aberration correction locally in each lens position.
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 proposed optical system effectively corrects a range of aberrations, enhancing imaging performance and stability, particularly in camera applications, by using crystalline glass lenses and diffractive optical elements to achieve optimal optical performance and vibration compensation.
Implementation Method 1
an optical system OL includes a diffractive optical element GD
Implementation Method 2
at least one lens made of crystalline glass
Data Source
AI summary
[Problem to be Solved]There are provided an optical system having good imaging performance, an optical apparatus, and a method for manufacturing the optical system.[Solution]An optical system OL used in an optical apparatus, such as a camera 1, includes a diffractive optical element GD and at least one specific lens Lp, which is a lens made of crystalline glass. The specific lens Lp satisfies the condition expressed by the following expression: θgFp+0.0017×νdp<0.730, where θgFp represents partial dispersion ratio of a medium of the specific lens Lp, and νdp represents the Abbe number of the medium of the specific lens Lp at a d line.