Zoom Lens Segmented Groups for High Magnification Compact Size
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Solution Overview
Problem
There is a demand for a zoom lens that is reduced in size and has high magnification while maintaining favorable optical performance, particularly for applications in imaging apparatuses such as broadcast cameras and digital cameras.
Innovation Solution
A zoom lens configuration comprising a first lens group with positive refractive power, a middle group with multiple lens groups that move during zooming, and a final lens group that remains stationary, with an image side movable lens group having negative refractive power, adhering to specific conditional expressions to achieve both high magnification and reduced size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a zoom lens is designed for high magnification, then the magnification capability is improved, but the lens size increases
Solution Approach 1:
The zoom lens is divided into multiple lens groups (first lens group with positive refractive power, middle group with multiple movable lens groups, and final lens group with positive refractive power). This segmentation allows each group to contribute differently to the overall magnification, enabling high magnification capability while keeping individual group sizes manageable and the overall lens compact.
Solution Approach 2:
The patent employs movable lens groups within the middle group that change spacing during zooming operations. The image side movable lens group specifically has negative refractive power and its lateral magnification varies dynamically between wide angle end (βnW) and telephoto end (βnT) to achieve high magnification ratio while maintaining a compact form factor.
2Measurement precision
If lens groups are moved during zooming to achieve high magnification, then the magnification ratio is improved, but the complexity of the lens structure increases
Solution Approach 1:
The middle group is segmented into multiple lens groups with different functions: some lens groups move to change focal length, while the image side movable lens group moves to adjust magnification. This functional segmentation allows complex zooming behavior to be achieved through coordinated movement of simpler subsystems rather than a single complex mechanism.
Solution Approach 2:
The patent defines specific dynamic behavior for the image side movable lens group, where its lateral magnification at telephoto end (βnT) and wide angle end (βnW) must satisfy Conditional Expression (1). This dynamic constraint ensures high magnification ratio is achieved while the movement patterns remain systematic and controllable, preventing excessive structural complexity.
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 proposed zoom lens design achieves high magnification and reduced size while effectively correcting various aberrations, ensuring favorable optical performance across different zooming states.
Implementation Method 1
a first lens group that has a positive refractive power; a middle group that includes a plurality of lens groups each moving by changing a spacing with an adjacent lens group during zooming; and a final lens group that remains stationary with respect to an image plane during zooming and has a positive refractive power
Data Source
AI summary
The zoom lens consists of, in order from an object side: a first lens group that has a positive refractive power, a middle group that includes a plurality of lens groups each moving by changing a spacing with an adjacent lens group during zooming; and a final lens group that remains stationary during zooming and has a positive refractive power. Among the plurality of lens groups that move during zooming in the middle group, an image side movable lens group, which is a lens group disposed closest to the image side, has a negative refractive power.