Zoom Lens Layout With Fixed Front Group and Moving Intermediate Units
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving a balance between high magnification variation, optical performance, and compact size while minimizing the weight and moving amounts of lens units during zooming, particularly in variator systems.
Innovation Solution
A zoom lens configuration with a stationary first lens unit and moving intermediate lens units, featuring positive and negative refractive powers, that adheres to specific inequalities to optimize focal lengths, moving amounts, and optical distances, reducing the size and weight of movable lens units and enhancing aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the zoom lens uses a conventional variator system with moving lens units to achieve high magnification variation, then the focal length range is improved, but the size and weight of movable lens units increase
Solution Approach 1:
The zoom lens is divided into multiple lens units with different functions: a first lens unit with negative refractive power that remains stationary during zooming, and subsequent lens units that move to achieve magnification variation. This segmentation allows the heavy first lens unit to be fixed while lighter subsequent units perform the zooming function, resolving the contradiction between magnification variation and movable weight
Solution Approach 2:
Conventionally, the first lens unit in a zoom lens moves during zooming. This invention inverts the approach by making the first lens unit stationary and having subsequent lens units move instead. This inversion reduces the weight of movable components while maintaining the ability to achieve high magnification variation
2Reliability
If the zoom lens increases the number of lenses in the first lens unit to improve aberration correction, then the optical performance is improved, but the complexity of the lens structure increases
Solution Approach 1:
The lens system is segmented into multiple functional units: the first lens unit with negative refractive power for aberration correction and focusing, and subsequent lens units for magnification variation. This functional segmentation allows each unit to be optimized independently, achieving high optical performance without excessive overall complexity
Solution Approach 2:
Different regions of the lens system are assigned different optical properties: the first lens unit uses negative refractive power specifically for correcting aberrations and enabling close-distance focusing, while subsequent units have positive refractive power for magnification control. This local optimization of optical properties achieves high performance without uniform complexity throughout the system
3Speed
If the zoom lens reduces the moving amount of intermediate lens units to achieve fast and quiet zooming, then the zooming speed is improved, but the ability to correct aberrations during zooming is worsened
Solution Approach 1:
The zooming function is segmented across multiple lens units with different moving amounts. The first intermediate lens unit moves by a smaller amount (|mp1|) while the second intermediate lens unit moves by a larger amount (|mp2|), where 0.3 ≤ |mp2/mp1| ≤ 0.8. This segmented approach allows fast zooming (reduced total moving distance) while maintaining aberration correction capability through the coordinated movement of multiple units
Solution Approach 2:
The invention optimizes the ratio of moving amounts between intermediate lens units as a key parameter. By setting 0.3 ≤ |mp2/mp1| ≤ 0.8, the system achieves an optimal balance where the first intermediate lens unit moves enough to contribute to aberration correction while the second unit provides additional correction and magnification variation, enabling fast zooming without sacrificing optical 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 solution enables fast, quiet, and high-performance zooming with reduced lens unit sizes and weights, effectively correcting aberrations and image blur, while maintaining optical integrity across the zoom range.
Implementation Method 1
a first lens unit with negative refractive power
Implementation Method 2
an intermediate group with positive refractive power as a whole. The intermediate group includes a first intermediate lens unit with positive refractive power, and a second intermediate lens unit with positive refractive power
Data Source
AI summary
A zoom lens includes, in order from an object side to an image side, a first lens unit with negative refractive power, an intermediate group with positive refractive power as a whole, and a subsequent group with negative refractive power as a whole. The intermediate group includes a first intermediate lens unit with positive refractive power, and a second intermediate lens unit with positive refractive power adjacent to and disposed on the image side of the first intermediate lens unit. During zooming, the first lens unit is stationary, and the first intermediate lens unit and the second intermediate lens unit move, and each distance between adjacent lens units changes. The first lens unit includes two or more lenses. Predetermined inequalities are satisfied.