Variable Magnification Lens System Compact Focusing Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional variable magnification optical systems do not adequately consider weight reduction, leading to larger lens barrels and increased weight, which can result in slower and noisier focusing, as well as unsuppressed aberrations during magnification and focusing.
Innovation Solution
A variable magnification optical system comprising four lens groups with specific refractive powers, where the distances between these groups are varied to achieve optimal focal lengths and suppress aberrations, with the fourth lens group acting as a focusing lens to maintain compactness and reduce weight, while satisfying conditional expressions to control refractive power ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional variable magnification optical system is used, then optical function is achieved, but weight and lens barrel size are large
Solution Approach 1:
The optical system is divided into four distinct lens groups with specific refractive powers (positive, negative, positive, negative). Each group can be independently positioned and adjusted, allowing the system to achieve variable magnification while maintaining compact overall size and reduced weight compared to conventional monolithic designs.
Solution Approach 2:
The patent implements dynamic adjustment of distances between lens groups to achieve variable magnification. The fourth lens group is made movable for focusing, and the distances between groups can be varied to transition between wide angle and telephoto states, enabling adaptability without increasing weight.
2Speed
If larger lens barrel is used, then optical performance is maintained, but focusing speed decreases and noise increases
Solution Approach 1:
The fourth lens group is designed to be movable for focusing purposes, allowing the system to achieve focus adjustment within a compact space. This dynamic positioning enables fast focusing without requiring a long stationary lens barrel, thereby improving focusing speed while maintaining compact dimensions.
3Reliability
If conventional optical system is used, then basic focusing is achieved, but aberrations are not suppressed during magnification and focusing
Solution Approach 1:
The system uses four segmented lens groups with alternating positive and negative refractive powers. This segmentation allows for sophisticated aberration correction by distributing optical functions across multiple groups, achieving stable optical performance during magnification and focusing while managing complexity through modular design.
Solution Approach 2:
Each lens group is designed with specific refractive power characteristics tailored to its function in the optical path. The alternating positive-negative arrangement creates local optical zones that work together to suppress aberrations, with each group contributing specific correction capabilities to the overall system 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
The system achieves high-speed, quiet focusing with reduced lens barrel size and effectively suppresses aberrations across various magnification states and focusing distances, ensuring excellent optical performance.
Implementation Method 1
a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having negative refractive power
Data Source
AI summary
A variable magnification optical system comprises, in order from an object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power and a fourth lens group G4 having negative refractive power; upon varying a magnification, a distance between the first lens group G1 and the second lens group G2 being varied, a distance between the second lens group G2 and the third lens group G3 being varied, and a distance between the third lens group G3 and the fourth lens group G4 being varied; upon focusing, the fourth lens group G4 being moved; and a predetermined conditional expression being satisfied. With such a configuration, there is provided a variable magnification optical system whose focusing lens group is compact in size and reduced in weight, so high speed and quiet focusing can be effected without lens barrel being made large in size, and further by which variations in aberrations upon varying magnification from the wide angle end state to the telephoto end state as well as variations in aberrations upon focusing from the infinite distance object to the close distance object can be superbly suppressed.