Cemented Lens Layout for Thermal-Stable Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image pickup apparatuses face challenges in maintaining high imaging performance and preventing lens separation or damage due to large temperature changes, especially in cemented lenses with significant differences in refractive index and dispersion, leading to stress and potential cracking.
Innovation Solution
The optical system employs cemented lenses with specific refractive index ranges and focal length relationships to balance chromatic aberration and field curvature correction while minimizing linear expansion differences, using materials with high refractive indexes to prevent separation and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a cemented lens uses materials with large difference in refractive index and dispersion to correct chromatic aberration and field curvature, then imaging performance is improved, but linear expansion difference increases causing lens separation and cracking under temperature changes
Solution Approach 1:
The patent changes the material parameters by selecting glass types with high refractive indexes (Np1>1.70, Np2>1.70, Nn1>1.70, Nn2>1.70) and controlling the ratio of refractive index difference to dispersion difference (Np1-Nn1)/(νp1-νn1) and (Np2-Nn2)/(νp2-νn2) to be greater than 0.003. This parameter optimization allows achieving both high imaging performance and thermal stability simultaneously
Solution Approach 2:
The patent uses composite material design by combining multiple glass types with specific properties in the cemented lens structure. The first cemented lens combines positive and negative lenses made of different glass materials, and the second cemented lens similarly combines different glass types, creating a multi-material system that balances optical performance and thermal expansion compatibility
2Measurement precision
If materials with high refractive indexes are used in cemented lenses, then chromatic aberration correction is improved, but manufacturing precision requirements increase due to tighter material selection constraints
Solution Approach 1:
The patent defines specific parameter ranges for glass materials (refractive indexes greater than 1.70, specific dispersion values, and controlled ratios of refractive index difference to dispersion difference). These parameter specifications provide clear manufacturing guidelines that balance performance requirements with manufacturability, making the design both high-performance and manufacturable
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 system achieves high imaging performance by correcting chromatic aberration and field curvature while preventing lens separation and cracking, even under large temperature changes.
Implementation Method 1
corrects chromatic aberration and field curvature by using a refractive index difference or a dispersion difference between a positive lens and a negative lens of a cemented lens
Implementation Method 2
corrects chromatic aberration and field curvature by using a refractive index difference or a dispersion difference between a positive lens and a negative lens of a cemented lens
Implementation Method 3
a difference between linear expansion coefficients (linear expansion difference) of the positive lens and the negative lens are likely to be large. In a case where the linear expansion difference of the positive lens and the negative lens is large, if a large temperature change occurs, a large stress is caused by an expansion difference and/or a contraction difference of cemented surfaces
Data Source
AI summary
A system includes an aperture diaphragm, a first lens configured to be disposed next to the aperture diaphragm on an object side, and to include one or more positive lenses and one or more negative lenses, and a second lens configured to be disposed next to the aperture diaphragm on an image side, and to include one or more positive lenses and one or more negative lenses. Predetermined conditions are satisfied.