Four-Group Zoom Optics With Fixed Front Group and Aberration Control
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Solution Overview
Problem
Existing zoom optical systems face challenges in achieving both excellent optical performance and size reduction.
Innovation Solution
A zoom optical system comprising a specific configuration of lens groups with fixed first lens group and varying distances between adjacent groups, adhering to conditional expressions for focal length ratios, and incorporating a vibration-proof lens group to correct aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional zoom optical system configurations are used, then optical performance can be maintained, but the system size cannot be reduced
Solution Approach 1:
The patent applies parameter changes by establishing specific conditional expressions for focal length ratios (0.45 < |f1/f3| < 0.65 and 0.80 < |f2/f3| < 1.10) and optimizing the movement amounts of lens groups during zooming. These parameter optimizations enable compact design while maintaining aberration correction performance, resolving the contradiction between size reduction and optical performance.
2Device complexity
If the first lens group is fixed during zooming, then the optical system can be simplified, but aberration correction becomes more difficult
Solution Approach 1:
The patent optimizes the focal length parameters of the movable lens groups (second and third lens groups) to satisfy specific conditional expressions. This parameter optimization compensates for the simplified structure, enabling effective aberration correction even with the first lens group fixed during zooming.
Solution Approach 2:
The patent implements dynamic aberration correction by allowing the second and third lens groups to move during zooming operations. This dynamic configuration enables the system to maintain optimal optical performance across different focal lengths while keeping the first lens group fixed, balancing structural simplicity with correction effectiveness.
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 optical performance with reduced size and improved aberration correction, enabling compact optical devices with enhanced imaging capabilities.
Implementation Method 1
a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power
Data Source
AI summary
A zoom optical system (ZL) comprises, in order from an object side along an optical axis, a first lens group (G1) having a negative refractive power, a second lens group (G2) having a positive refractive power, a third lens group (G3) having a negative refractive power, and a fourth lens group (G4) having a positive refractive power, and upon zooming, the first lens group (G1) is fixed relative to an image surface, and a distance between adjacent lens groups is varied, and the following conditional expressions are satisfied:0.7<(-f1)/f2<1.30.55<f2/(-f3)<1.2where f1: a focal length of the first lens group,f2: a focal length of the second lens group, andf3: a focal length of the third lens group.