Large-Aperture Lens Layout for Lightweight Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical systems face challenges in achieving weight reduction while effectively correcting various aberrations, particularly chromatic aberration, at a large aperture ratio, and often result in a heavy focusing lens group and increased total lens length.
Innovation Solution
The optical system is configured with a first lens group having negative refractive power, a second lens group that moves along the optical axis during focusing, and a last lens group with an aperture diaphragm between the second and last lens groups, utilizing specific lens arrangements and aspherical lenses to correct aberrations and reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the lens configuration before and after the aperture diaphragm is appropriately maintained during focusing, then high optical performance with bright wide angle of view is achieved, but the weight of the focusing lens group becomes heavy
Solution Approach 1:
The lens system is divided into three distinct lens groups (first lens group with negative refractive power, second lens group that moves during focusing, and last lens group with aperture diaphragm). This segmentation allows each group to be optimized independently for its specific function, enabling weight reduction in the focusing lens group while maintaining overall optical performance through coordinated design of the segments.
Solution Approach 2:
The second lens group is designed to move along the optical axis during focusing from infinity to short distance, while the first and last lens groups remain fixed. This dynamic configuration allows the focusing lens group to be positioned optimally for high optical performance at large aperture ratios while reducing its weight by removing unnecessary lens elements that would be required if the entire lens group moved.
2Weight of moving object
If the weight of the focusing lens group is suppressed at a large aperture ratio, then weight reduction is achieved, but the longitudinal chromatic aberration, lateral chromatic aberration, and sagittal coma flare are not sufficiently corrected
Solution Approach 1:
Each lens group is designed with specific local functions: the first lens group (negative refractive power) corrects certain aberrations, the second lens group (moving group) handles focusing and additional aberration correction, and the last lens group (with aperture diaphragm) optimizes optical performance. This local quality assignment allows adequate aberration correction with reduced weight by distributing correction functions across specialized groups rather than requiring high precision throughout the entire focusing lens group.
Solution Approach 2:
The patent employs different lens materials with specific refractive indices and Abbe numbers in each lens group to achieve aberration correction. By selecting appropriate material combinations for each group (e.g., using negative refractive power lens for the first group and specific materials for the moving group), the system corrects chromatic aberration and coma flare while maintaining weight reduction in the focusing lens group.
3Weight of moving object
If the weight of the focusing lens group is reduced by fixing the lens group from the object side to the aperture diaphragm, then weight reduction is achieved, but the total lens length becomes long and the overall length becomes large
Solution Approach 1:
The lens system is segmented into three groups with the aperture diaphragm positioned between the second and last lens groups. This segmentation allows the focusing lens group (second group) to be fixed in position during focusing operations, reducing its weight, while the overall lens length is controlled by the compact arrangement of the three segments rather than requiring a long continuous structure.
Solution Approach 2:
The patent arranges the lens groups in a specific spatial dimensionality with the aperture diaphragm positioned between the second and last lens groups. This dimensional arrangement allows the focusing lens group to be fixed while maintaining compact overall length, as the groups are distributed in space rather than requiring linear extension along the optical axis.
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 weight reduction while effectively correcting chromatic aberration and other optical aberrations, maintaining a compact size and ensuring high optical performance at a large aperture ratio.
Implementation Method 1
a first lens group G1 having a negative refractive power
Implementation Method 2
a second lens group G2 that moves along an optical axis during focusing from infinity to a short distance
Implementation Method 3
an aperture diaphragm S is provided between the second lens group G2 and the last lens group GL
Implementation Method 4
utilizing specific lens arrangements and aspherical lenses to correct aberrations
Data Source
AI summary
An optical system that achieves weight reduction while correcting various aberrations such as chromatic aberration at a large aperture ratio by arranging lens materials appropriately. An optical system includes, in order from an object side: a first lens group G1 having a negative refractive power; a second lens group G2 that moves along an optical axis during focusing from infinity to a short distance; and a last lens group GL that is disposed closest to the image surface side, in which an aperture diaphragm S is provided between the second lens group G2 and the last lens group GL.