Moving-Focus Optical System for Compact Chromatic Aberration Correction
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Solution Overview
Problem
Existing optical systems face challenges in achieving both improved optical performance and reduced size and weight, particularly in telephoto lenses where chromatic aberrations and other aberrations are prevalent.
Innovation Solution
The optical system is configured with a front group having positive refractive power and a focusing group that moves along the optical axis, comprising specific lenses arranged to satisfy conditional expressions that optimize the distance and refractive power ratios, ensuring effective aberration correction and size reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the optical system uses conventional lens arrangements to achieve small size and light weight, then the size and weight are reduced, but the optical performance and aberration correction are insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the conditional expression 0.10 < D23/f1 < 0.40, where D23 is the distance between the second and third lenses and f1 is the focal length of the front group. This parameter optimization enables simultaneous achievement of compact size, reduced weight, and improved aberration correction performance.
Solution Approach 2:
The patent employs composite lens design combining multiple lens elements with different refractive powers and Abbe numbers. The front group includes a positive second lens and a negative third lens with specific material properties, creating a composite optical structure that corrects chromatic and other aberrations while maintaining compact dimensions.
2Length of moving object
If the optical system reduces the number of lens elements to decrease size, then the size is reduced, but the aberration correction capability deteriorates
Solution Approach 1:
The patent optimizes the distance parameter D23 between the second and third lenses relative to the focal length f1, establishing the conditional expression 0.10 < D23/f1 < 0.40. This parameter control enables effective aberration correction with a limited number of lens elements, achieving compact size without sacrificing optical performance.
Solution Approach 2:
The patent assigns specific local properties to each lens element: the second lens has positive refractive power with specific Abbe number constraints (40 < vL2 < 90), and the third lens has negative refractive power with specific Abbe number constraints (20 < vL3 < 60). This localized optimization of lens properties enables effective aberration correction in a compact configuration.
3Reliability
If the optical system increases lens elements to improve aberration correction, then the aberration correction is improved, but the weight and complexity increase
Solution Approach 1:
The patent establishes optimized parameter ranges including 0.10 < D23/f1 < 0.40, 40 < vL2 < 90, and 20 < vL3 < 60. These parameter constraints enable effective aberration correction using only three lens elements in the front group, avoiding the need for additional heavy elements while maintaining high optical performance.
Solution Approach 2:
The patent extracts and concentrates the aberration correction function into the front group with three specifically designed lens elements. By concentrating the correction function in this compact arrangement with optimized parameters, the patent eliminates the need for additional heavy lens elements elsewhere in the system.
4Reliability
If the optical system uses complex lens arrangements to correct chromatic aberrations, then the chromatic aberration correction is improved, but the device complexity increases
Solution Approach 1:
The patent optimizes the conditional expression 0.10 < D23/f1 < 0.40 and the Abbe number ranges for the second and third lenses. These parameter optimizations enable effective chromatic aberration correction through a simple three-element front group configuration, avoiding complex multi-element arrangements.
Solution Approach 2:
The patent uses composite lens design with the second lens (positive power, 40 < vL2 < 90) and third lens (negative power, 20 < vL3 < 60) forming a compact achromatic doublet structure. This composite arrangement corrects chromatic aberrations effectively while maintaining simple configuration and low complexity.
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 achieves favorable aberration correction, particularly in chromatic aberrations, while reducing the overall size and weight of the optical system, enhancing its imaging performance.
Implementation Method 1
a front group having positive refractive power; and a focusing group that performs focusing by moving in an optical axis direction
Data Source
AI summary
An optical system and an optical apparatus that have favorable imaging performance and a method for manufacturing the optical system are provided. An optical system OL includes, sequentially from an object side, a front group G1 having positive refractive power and a focusing group G2 that performs focusing by moving in an optical axis direction, the front group G1 includes, sequentially from the object side, a first lens L11, a second lens L12, and a third lens L13, and the optical system OL satisfies a condition expressed by an expression below,0.10<D23/f1<0.75in the expression,f1: focal length of the front group G1, andD23: distance on an optical axis between the second lens L12 and the third lens L13.