Zoom Lens Compact Design via Segmented Optics
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Solution Overview
Problem
Existing zoom lenses face challenges in reducing size and weight while maintaining optical performance, particularly in correcting aberrations during focusing and zooming.
Innovation Solution
A zoom lens configuration that includes a first lens unit with positive refractive power, a second and third lens unit, and a rear group with a focus lens unit having negative refractive power, where the distance between adjacent lens units changes during zooming, and the focus lens unit moves towards the object side during focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If high refractive power lens units are used to reduce zoom lens size, then the lens size is reduced, but aberration fluctuations increase during zooming
Solution Approach 1:
The zoom lens is divided into multiple lens units (first lens unit L1, second lens unit L2, third lens unit L3, and rear group LR) with different functions. The first lens unit with positive refractive power handles zooming, while the rear group containing the focus lens unit handles focusing, allowing each segment to be optimized independently for size and aberration control
Solution Approach 2:
The distances between adjacent lens units are made variable during zooming operations. Specifically, the distance between L1 and L2 increases, the distance between L2 and L3 increases, and the distance between L3 and the rear group increases during zooming from wide-angle to telephoto end, enabling dynamic aberration compensation while maintaining compact size
2Weight of moving object
If the first lens unit is configured for weight reduction, then the lens weight is reduced, but the effective diameter increases
Solution Approach 1:
The first lens unit L1 is designed with specific local optical properties (positive refractive power and particular focal length relationship) that allow it to achieve weight reduction through optimized material distribution and structural design while maintaining the necessary effective diameter for its zooming function
3Reliability
If the focus lens unit is arranged to suppress fluctuations during focusing, then optical performance stability is improved, but the moving amount increases
Solution Approach 1:
The third lens unit L3 acts as an intermediary element between the zooming mechanism (L1) and the focusing mechanism (rear group LR). By positioning L3 between these functional groups and adjusting its distance relationships, the patent mediates the mechanical movements to reduce the actual moving distance required by the focus lens unit while maintaining optical performance stability
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 configuration achieves a reduced size and weight of the zoom lens with minimal fluctuations in optical performance during focusing, allowing for efficient zooming and focusing operations.
Implementation Method 1
a first lens unit L1 having positive refractive power
Implementation Method 2
a rear group LR including a focus lens unit having negative refractive power. The focus lens unit moves toward the object side during focusing from an object at infinity to an object at a close distance
Data Source
AI summary
A zoom lens includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit, a third lens unit, and a rear group including a plurality of lens units. A distance between adjacent lens units changes during zooming. During zooming from a wide-angle end to a telephoto end, the first lens unit moves toward the object side, a distance between the first lens unit and the second lens unit increases, a distance between the second lens unit and the third lens unit increases, and a distance between the third lens unit and the rear group increases. The rear group includes a focus lens unit having negative refractive power. The focus lens unit moves toward the object side during focusing from an object at infinity to an object at a close distance.