Imaging Lens Aberration Correction via Negative Lens Parameter Control
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Solution Overview
Problem
Existing imaging lenses face challenges in simultaneously correcting chromatic aberration, field curvature, and defocusing due to temperature changes, particularly when using materials with high abnormal dispersibility, as they require a trade-off between refractive index and temperature stability.
Innovation Solution
The design combines negative and positive lenses with specific refractive index, Abbe number, and partial dispersion ratios to optimize chromatic aberration correction while maintaining temperature stability, using Conditional Expressions to ensure effective aberration correction across various temperature ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a material having large abnormal dispersibility is used in a positive lens to correct secondary spectrum of chromatic aberration, then chromatic aberration correction is improved, but defocusing occurs during temperature rise due to large change in refractive index
Solution Approach 1:
The invention changes the material parameters by selecting a negative lens material with specific refractive index (1.65-1.75), Abbe number (45-55), and temperature coefficient (0-1×10^-6/°C). This parameter selection enables the negative lens to compensate for the positive lens's temperature sensitivity while maintaining chromatic aberration correction through the specified abnormal dispersibility relationship.
2Reliability
If a negative lens having large abnormal dispersibility is used to correct defocusing with temperature change, then temperature correction is improved, but field curvature correction becomes insufficient due to use of low refractive index material
Solution Approach 1:
The invention resolves this contradiction by precisely controlling the negative lens material parameters: refractive index (1.65-1.75) ensures adequate field curvature correction capability, Abbe number (45-55) maintains chromatic aberration correction, and temperature coefficient (0-1×10^-6/°C) provides temperature stability. The combination of these parameters achieves all three correction goals simultaneously.
3Measurement precision
If materials with high abnormal dispersibility are used to achieve high-definition imaging, then chromatic aberration correction is improved, but temperature sensitivity increases causing focus position drift
Solution Approach 1:
The invention uses a composite lens system combining a positive lens with high abnormal dispersibility (for chromatic aberration correction) and a negative lens with specific material properties (for temperature stability). The composite structure enables the system to achieve high-definition imaging while the negative lens compensates for temperature-induced focus drift through its controlled refractive index change characteristics.
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 enables comprehensive correction of chromatic aberration and field curvature while effectively addressing defocusing issues caused by temperature changes, ensuring high-definition imaging performance across different conditions.
Implementation Method 1
a material having large abnormal dispersibility is effective in correcting a secondary spectrum of chromatic aberration
Implementation Method 2
a material having large abnormal dispersibility has a large change in refractive index with respect to a change in temperature, and that the use of this material in a positive lens causes a focus position to extend during a rise in temperature
Implementation Method 3
a material having large abnormal dispersibility is effective in correcting a secondary spectrum of chromatic aberration
Data Source
AI summary
The imaging lens includes at least one negative lens that satisfies predetermined Conditional Expressions (1) to (3) indicating conditions in which dispersion is relatively low and refractive index is high while having a negative rate of change of the refractive index. A positive lens having a largest Abbe number at the d line among positive lenses included in the imaging lens satisfies predetermined Conditional Expressions (4) and (5).