Zoom Optical System Aberration Control via Fixed Lens Group
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Solution Overview
Problem
Conventional zoom optical systems experience significant variation in aberrations during zooming, affecting optical performance.
Innovation Solution
A zoom optical system comprising a specific configuration of lens groups with positive and negative refractive powers, where the second lens group is fixed upon zooming, and at least a portion of the fifth lens group is movable along the optical axis, with conditional expressions defining optimal focal length ratios and movements to minimize aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional zoom optical system is used, then the system can achieve zooming function, but variation in aberrations upon zooming is large
Solution Approach 1:
The optical system is divided into five lens groups with specific refractive power distributions. The first lens group has positive refractive power, the second has negative refractive power, the third has positive refractive power, the fourth has positive refractive power, and the fifth has negative refractive power. This segmentation allows each group to contribute to correcting specific aberrations at different zoom positions.
Solution Approach 2:
The second lens group is designed to be fixed during zooming from wide-angle to telephoto end state, while the fifth lens group is made movable along the optical axis for focusing. This dynamic configuration allows the system to maintain optimal aberration correction across different focal lengths while enabling focusing functionality.
2Manufacturing precision
If the second lens group is fixed upon zooming, then aberration variation is reduced, but device complexity increases
Solution Approach 1:
The fixed second lens group serves multiple functions: it acts as a reference frame for zooming, contributes to aberration correction, and maintains optical alignment. By making this single group fixed, the system achieves stable aberration control without requiring multiple fixed groups, thus limiting the increase in device complexity.
3Ease of operation
If the fifth lens group is movable along optical axis, then focusing is enabled, but aberration control becomes more difficult
Solution Approach 1:
The fifth lens group is specifically designed with negative refractive power and is positioned to be movable only for focusing operations. This localized mobility allows focusing functionality without affecting the aberration correction provided by the fixed second lens group and the other movable lens groups, thus maintaining aberration control while enabling focusing.
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 significantly reduces aberration variations, enabling excellent optical performance across zooming states by maintaining compactness and correcting spherical and chromatic aberrations.
Implementation Method 1
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, a fourth lens group G4 having positive refractive power, and a fifth lens group G5 having negative refractive power
Data Source
AI summary
Composing a zoom optical system ZL, 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, a fourth lens group G4 having positive refractive power, and a fifth lens group G5 having negative refractive power; and disposing each lens group with satisfying a given conditional expression (1); thereby providing a zoom optical system ZL capable of suppressing variation in aberrations upon zooming and carrying out excellent vibration reduction, an optical apparatus equipped therewith, and a method for manufacturing the zoom optical system.