Telephoto Optical System Aberration Correction via Lens Parameter Control
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Solution Overview
Problem
Telephoto-type optical systems with long focal lengths face challenges in achieving both accurate aberration correction and weight reduction, as the configuration that effectively corrects chromatic aberration often results in a larger and heavier optical system due to the arrangement of multiple lenses with large effective diameters.
Innovation Solution
The optical system is designed with specific conditions for the placement and Abbe numbers of positive lenses, including a positive lens G1 and G2, to optimize the distance and refractive power distribution, ensuring LD/f < 1, 0.200 < D12/LD < 0.600, and appropriate Abbe numbers for the lenses, which allows for effective aberration correction while reducing the overall weight by minimizing lens diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple positive lenses are arranged on the object side with the widest gap in the first lens unit to correct chromatic aberration, then chromatic aberration correction is improved, but the effective diameter of each lens becomes relatively large and the weight of the optical system increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Abbe numbers of the positive lenses (νdG1 ≥ 73.00 and νdG2 ≥ 73.00) and the normalized distance between them (0.200 < D12/LD < 0.600). These parameter specifications enable effective chromatic aberration correction while avoiding the need for large effective diameters, thus resolving the contradiction between correction accuracy and weight reduction.
2Length of moving object
If the total length of the optical system is shortened to reduce size, then compactness is improved, but the distance between lenses must be reduced which may affect aberration correction performance
Solution Approach 1:
The patent resolves this contradiction by establishing a specific parameter range for the normalized distance between positive lenses (0.200 < D12/LD < 0.600). This parameter control ensures that even in a compact optical system with shortened total length, the distance between lenses is optimized to maintain effective aberration correction performance.
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 configuration enables accurate correction of various aberrations, including chromatic aberration, while significantly reducing the weight of the optical system, making it suitable for lightweight imaging applications.
Implementation Method 1
a positive lens G1 arranged closest to an object side and a positive lens G2 arranged closest to the object side among a plurality of positive lenses at an image side of the positive lens G1
Data Source
AI summary
An optical system includes a positive lens G1 arranged closest to the object side and a positive lens G2 arranged closest to the object side among positive lenses at the image side of the positive lens G1. The optical system satisfies a predetermined condition.