Variable Magnification Lens Groups for Compact Aberration Correction
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Solution Overview
Problem
Existing variable magnification optical systems in lens exchangeable type cameras are not compact enough and do not provide sufficient optical performance.
Innovation Solution
A variable magnification optical system comprising a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group, where the intervals between neighboring lens groups are varied upon magnification change, and the first and second lens groups are moved along the optical axis, with specific conditional expressions to ensure proper focal length ratios and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional variable magnification optical systems are used in lens exchangeable type cameras, then optical performance can be maintained, but the system size cannot be sufficiently reduced
Solution Approach 1:
The patent applies dynamics by making the intervals between lens groups variable rather than fixed. The first, second, and third lens groups can adjust their relative positions dynamically during magnification variation, allowing the optical system to adapt its configuration for different focal lengths while maintaining compact overall size. This dynamic adjustment enables the system to achieve both compactness and optical performance.
2Adaptability or versatility
If the first and second lens groups are moved along the optical axis for focusing, then focusing capability is achieved, but the mechanical complexity increases
Solution Approach 1:
The patent merges the focusing function into the existing magnification variation mechanism. The same drive mechanism that varies magnification by adjusting intervals between lens groups also performs focusing by moving the first and second lens groups along the optical axis. This combination reduces mechanical complexity compared to having separate mechanisms for magnification and focusing.
3Reliability
If the ratio of focal lengths between the first and second lens groups is optimized, then aberration correction is improved, but the design constraints increase
Solution Approach 1:
The patent applies parameter changes by optimizing the ratio of focal lengths between the first and second lens groups within a specific range (0.3 < |f1/f2| < 0.7). This parameter optimization enables effective aberration correction while keeping the lens group configurations relatively simple. The conditional expression provides a quantitative guideline that balances performance with design simplicity.
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 achieves compactness and superior optical performance by effectively correcting spherical aberration, coma aberration, and other aberrations while maintaining a wide angle of view and high-quality imaging in various lighting conditions.
Implementation Method 1
a first lens group having negative refractive power, a second lens group having positive refractive power
Data Source
AI summary
A variable magnification optical system which comprises, in order from an object side, a first lens group having negative refractive power, a second lens group having positive refractive power and a third lens group; upon varying magnification, distances between the neighboring respective lens groups being varied; upon focusing, the first lens group and the second lens group being moved along the optical axis; and predetermined conditional expression(s) being satisfied, whereby the variable magnification optical system is made in small in size, and can correct superbly various aberrations.