Variable Magnification Optics for Compact Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing variable magnification optical systems face challenges in effectively correcting aberrations such as spherical, chromatic, and coma aberrations while maintaining a compact size and efficient operation across varying magnification ranges.
Innovation Solution
A variable magnification optical system is designed with a first negative lens group fixed relative to the image plane, varying spacings between lens groups, and strategically positioned aperture stops and negative lens groups to satisfy specific conditional expressions, ensuring appropriate aberration correction and system compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the first negative lens group is fixed relative to the image plane and spacings between lens groups are varied, then the system achieves compact size and efficient operation, but aberrations such as spherical, chromatic, and coma aberrations become difficult to correct
Solution Approach 1:
The optical system is divided into multiple lens groups (first negative lens group, second negative lens group, and other lens groups) with specific refractive powers. Each lens group can be positioned independently, allowing the first negative lens group to remain fixed while varying spacings between groups. This segmentation enables compact system design while maintaining aberration correction capability through strategic positioning of each segment.
Solution Approach 2:
The patent applies local quality by assigning specific refractive powers and positions to different lens groups. The first negative lens group has negative refractive power and is positioned at a specific location relative to the image plane, while the second negative lens group has a focal length satisfying a specific conditional expression. This localized optimization of optical properties at different positions enables effective aberration correction throughout the variable magnification range.
2Reliability
If aperture stop is disposed closer to the image plane side than the first negative lens group, then the system achieves better aberration correction, but the system complexity increases
Solution Approach 1:
The aperture stop serves multiple functions: it controls the amount of light entering the system, defines the entrance pupil position, and contributes to aberration correction by being positioned at a specific location. By placing the aperture stop closer to the image plane side than the first negative lens group, the system achieves effective aberration correction while the aperture stop simultaneously performs its light control function, avoiding the need for additional dedicated correction elements.
3Reliability
If the second negative lens group is disposed adjacent to the image plane side of the aperture stop and satisfies the conditional expression 0.00 < fA/fCα < 0.30, then chromatic and spherical aberrations are effectively corrected, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a conditional expression for the ratio of focal lengths (0.00 < fA/fCα < 0.30) rather than fixed values, allowing flexibility in manufacturing. This parameter range optimization enables effective aberration correction while accommodating normal manufacturing tolerances. The conditional expression defines an optimal range that balances performance with manufacturability, avoiding overly stringent precision requirements.
4Productivity
If multiple lens groups with varying spacings are used to achieve variable magnification, then the system achieves efficient operation across magnification ranges, but coma aberration correction becomes challenging
Solution Approach 1:
The optical system is designed with dynamic spacing between lens groups to enable variable magnification operation. The first negative lens group remains fixed while the spacings between adjacent lens groups can be varied, allowing the system to efficiently operate across different magnification ranges. This dynamic positioning, combined with the specific configuration of negative lens groups, maintains coma aberration correction effectiveness throughout the magnification range.
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 effectively corrects aberrations including spherical, chromatic, and coma aberrations across varying magnification ranges, while minimizing system size and weight, by adhering to specific focal length and movement ratio constraints.
Implementation Method 1
a first negative lens group having negative refractive power and a rear group including a plurality of lens groups
Data Source
AI summary
A variable magnification optical system including, in order from the object side, a first negative lens group having negative refractive power and a rear group including a plurality of lens groups is configured so that at varying magnification, the first negative lens group being fixed with respect to the image plane and the spacings between adjacent lens groups being varied, an aperture stop being disposed closer to the image plane side than the first negative lens group, a second negative lens group disposed adjacent to the image plane side of the aperture stop among the plurality of lens groups included in the rear group having negative refractive power, and that the following conditional expression is satisfied:0.00<fA/fCα<0.30where fA is the focal length of the first negative lens group, and fCα is the focal length of the second negative lens group.