Zoom Lens Group Layout for Aberration Control Across Focus Range
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Solution Overview
Problem
Existing imaging optical systems struggle to compensate for various types of aberrations effectively across the entire zoom range, leading to suboptimal image quality.
Innovation Solution
An imaging optical system comprising a specific arrangement of lens groups with varying powers and movements, including a fifth lens group composed of two negative meniscus lenses, which compensates for aberrations by adjusting the intervals between lens groups and focusing the fifth lens group towards the image plane during zooming and focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional zoom lens system with multiple lens groups is used, then the zoom range is achieved, but the ability to compensate for various types of aberrations over the entire zoom range is insufficient
Solution Approach 1:
The zoom lens system is divided into seven distinct lens groups (G1-G7) with alternating positive and negative powers, arranged in sequence from the object side to the image plane side. This segmentation allows each lens group to independently contribute to aberration compensation while maintaining the overall zoom functionality across the entire zoom range.
Solution Approach 2:
Each lens group is specifically designed with particular optical characteristics (positive or negative power) to address specific aberration types at different positions in the optical path. The fifth lens group (G5) with negative power and the seventh lens group (G7) with positive power are strategically positioned to compensate for residual aberrations, ensuring high image quality throughout the zoom range.
2Ease of operation
If the fifth lens group moves during focusing, then the transition from infinity to close-object focus is achieved, but the interval between lens groups must be precisely controlled
Solution Approach 1:
The fifth lens group (G5) is designed to move along the optical axis during focusing operations, enabling dynamic adjustment of the focal plane from infinity to close-object distances. This dynamic movement is coordinated with the zooming action of other lens groups to maintain precise interval control and aberration compensation throughout the focusing range.
Solution Approach 2:
The fifth lens group serves multiple functions: it contributes to the overall zooming capability of the system while simultaneously providing focusing adjustment. This multi-functionality reduces the need for separate focusing mechanisms and simplifies the overall system design while maintaining precise control over the optical path intervals.
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 provides effective compensation for aberrations throughout the zoom range, enhancing image quality from wide-angle to telephoto ends and maintaining sharp focus from infinity to close-object distances.
Implementation Method 1
a first lens group having positive power; a second lens group having negative power; an aperture stop; a third lens group having positive power; a fourth lens group having positive power; a fifth lens group having negative power
Data Source
AI summary
An imaging optical system consists of: a first lens group having positive power; a second lens group having negative power; an aperture stop; a third lens group having positive power; a fourth lens group having positive power; a fifth lens group having negative power; and a rear lens group including at least one lens groups having power, where the first lens group is closest to an object. An interval between adjacent lens groups changes while the optical system is zooming from a wide-angle end toward a telephoto end. The fifth lens group consists of two negative meniscus lenses with convex surfaces facing the object and the image plane, respectively. The fifth lens group moves from the object toward the image plane while the optical system is focusing to make a transition from an infinity in-focus state toward a close-object in-focus state.