Variable-Magnification Optics with Fixed Aberration Correction Group
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing variable-magnification observation optical systems face challenges in reducing weight and complexity due to multiple lenses in moving groups, and struggle to simultaneously correct aberrations at the center and periphery.
Innovation Solution
A variable-magnification observation optical system with a configuration that includes an objective system, an erecting system, and an eyepiece system, where the objective system has positive, positive, and negative power groups, and the eyepiece system has positive power groups, with the erecting system between the first and second groups, and the fifth group featuring a negative meniscus lens and a positive lens with an air gap, allowing for opposite movement of the third and fourth groups along the optical axis to achieve zooming, and incorporating aspheric surfaces for aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple lenses are included in moving groups to correct aberration variation during zooming, then aberration correction is improved, but the weight and mechanical structure complexity increase
Solution Approach 1:
The invention extracts the aberration correction function from the moving groups by introducing a dedicated fixed group (fourth group) with negative power. This separates the zooming function (performed by moving groups) from the aberration correction function (performed by the fixed fourth group), allowing each to be optimized independently without compromising the other.
Solution Approach 2:
The fourth group with negative power serves multiple functions: it corrects aberration variation during zooming, contributes to the overall optical power balance, and maintains compact system length. This multi-functional design eliminates the need for additional lenses in moving groups that would otherwise be required for aberration correction.
2Reliability
If multiple lenses are included in moving groups to correct aberration variation during zooming, then aberration correction is improved, but the mechanical structure complexity increases
Solution Approach 1:
The invention extracts the aberration correction function from the moving groups by introducing a dedicated fixed group (fourth group) with negative power. This separates the zooming function (performed by moving groups) from the aberration correction function (performed by the fixed fourth group), allowing each to be optimized independently without compromising the other.
Solution Approach 2:
The optical system is segmented into distinct functional groups: objective system (first, second, third groups), erecting system, and eyepiece system (fourth, fifth groups). The fourth group with negative power is specifically assigned the function of correcting aberration variation, while moving groups handle only zooming. This functional segmentation simplifies the mechanical structure by reducing the number of components that require coordinated movement.
3Device complexity
If only a pair of doublet lenses are used in the group closest to the pupil, then the structure is simplified, but it becomes difficult to simultaneously correct aberrations at the center and periphery
Solution Approach 1:
The fourth group introduces a negative power lens with specific local optical properties that complement the positive power doublet lenses. This creates a distributed aberration correction strategy where different regions of the eyepiece system (center and periphery) are corrected by different lens elements, allowing simultaneous optimization of both central and peripheral aberrations.
Solution Approach 2:
The eyepiece system uses a composite lens configuration combining positive power doublet lenses and a negative power lens. This composite structure leverages the complementary optical properties of different lens types to correct various aberrations simultaneously, achieving better overall performance than a single lens type could provide.
4Volume of moving object
If the optical system is downsized for compactness, then portability is improved, but aberration correction becomes more difficult
Solution Approach 1:
The invention uses parameter optimization within the fourth group (negative power lens) and fifth group (positive power lenses) to achieve effective aberration correction in a compact form. By carefully selecting focal lengths, spacing, and lens curvatures, the system maintains excellent aberration correction performance while minimizing overall size. The conditional expressions provided in the patent define optimal parameter ranges that balance compactness with optical 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 results in a light, compact optical system that effectively corrects various aberrations across the field from center to periphery, reducing weight and size while maintaining high optical performance.
Implementation Method 1
the fifth group includes in order from the object side a negative meniscus lens and a positive lens with an air gap therebetween, the negative meniscus lens having a concave surface facing the object
Implementation Method 2
the fifth group has at least one aspheric surface
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A variable-magnification observation optical system includes an objective system, an erecting system, and an eyepiece system. The objective system includes a positive first group, a positive second group, and a negative third group in order from the object side. The eyepiece system includes a positive fourth group and a positive fifth group in order from the object side. The erecting system is located between the first group and the second group. The fifth group includes in order from the object side a negative meniscus lens and a positive lens with an air gap therebetween wherein the negative meniscus lens has a concave surface facing the object. The fifth group has at least one aspheric surface.