Zoom Lens Stabilizes Image Plane During Focal Length Adjustment
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Solution Overview
Problem
Existing optical systems for wide-angle imaging suffer from unstable image planes during zoom procedures, requiring refocusing and experiencing aberrations due to the movement of lens groups, which complicates focal length adjustments.
Innovation Solution
The optical system comprises a sequence of lens units with specific refractive powers and movable designs, where the second and third lens units have multiple lens groups that move along the optical axis to adjust focal length while maintaining a stable image plane, and the first and fourth units remain fixed, allowing for continuous focal length adjustment without shifting the image plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lens groups are moved to adjust focal length in existing optical systems, then focal length can be varied, but the image plane becomes unstable and refocusing is required
Solution Approach 1:
The optical system is divided into four distinct lens units with specific refractive power configurations. The second and third lens units are further segmented into multiple lens groups (first, second, and third lens groups) that can be independently moved. This segmentation allows selective movement of specific lens groups to adjust focal length while other units remain fixed to maintain image plane stability.
Solution Approach 2:
Instead of moving all lens groups to adjust focal length (conventional approach), this invention inverts the approach by keeping the first and fourth lens units fixed and only moving specific lens groups within the second and third lens units. This inversion of the conventional zoom mechanism resolves the contradiction by decoupling focal length adjustment from image plane displacement.
2Adaptability or versatility
If multiple lens groups are moved during zooming, then focal length range is extended, but aberrations increase due to complex lens movements
Solution Approach 1:
Different lens units are assigned different refractive power characteristics and movement properties. The second lens unit contains lens groups with specific refractive powers that move to adjust focal length, while the third lens unit contains lens groups that move to compensate for aberrations. This local differentiation of quality and function allows the system to extend focal length range while controlling aberrations through specialized design of each unit.
3Stability of the object's composition
If lens units are fixed during zooming, then image plane stability is maintained, but focal length adjustment capability is limited
Solution Approach 1:
The system implements a dynamic zoom mechanism where the second and third lens units are designed to move relative to each other along the optical axis during focal length adjustment. This dynamic configuration allows the optical system to maintain image plane stability (by keeping first and fourth units fixed) while achieving continuous focal length variation through the coordinated movement of intermediate lens units.
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 stabilizes the image plane during zooming, reduces aberrations, and allows for precise control of focal length adjustments, enhancing imaging quality by ensuring that the image plane remains fixed while varying the focal length.
Implementation Method 1
a second lens unit consisting of a first lens group and a second lens group, wherein both lens groups have positive refractive power, a third lens unit consisting of a lens group with negative refractive power
Data Source
AI summary
An optical system for imaging an object on an image acquisition unit. The optical system, from the object, comprises a first lens unit, a second lens unit, a third lens unit and a fourth lens unit in the direction of the image acquisition unit. The first lens unit comprises at least one lens group with negative refractive power. The second lens unit comprises at least one lens group with positive refractive power and the third lens unit comprises at least one lens group with negative refractive power. The second lens unit and the third lens unit overall comprise at least three lens groups. From the first lens unit in the direction of an image acquisition unit, the first lens group, the second lens group and then the third lens group are arranged. The three lens groups have a movable design for adjusting the focal length of the optical system.