Zoom Lens with Negative Focus Unit Between Positive Units
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Solution Overview
Problem
Conventional zoom lenses face challenges in achieving fast focusing while minimizing aberration variation during focusing, as increasing the refractive power of the focus lens unit leads to increased residual aberration and aberration variation, and decreasing it results in excessive movement and space constraints for the zooming lens unit, making it difficult to miniaturize the lens while maintaining high optical performance.
Innovation Solution
A zoom lens configuration with a focus lens unit having negative refractive power sandwiched between positive refractive power lens units, allowing for controlled movement and refractive power distribution to reduce aberration variation and enable miniaturization, while maintaining high optical performance across zoom and focus ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the refractive power of the focus lens unit is increased, then the amount of movement during focusing is reduced, but residual aberration and aberration variation increase
Solution Approach 1:
The lens system is divided into multiple lens units with different functions. The focus lens unit is separated from the zoom lens units, allowing independent optimization of focusing and zooming functions. This segmentation enables the focus lens unit to have high refractive power for reduced movement while aberrations are corrected by other lens units in the system.
Solution Approach 2:
Positive lens units are introduced as intermediary elements adjacent to the focus lens unit. These intermediary lens units help correct the aberrations generated by the high-power focus lens unit, allowing the focus lens unit to maintain high refractive power without excessive aberration variation.
2Manufacturing precision
If the refractive power of the focus lens unit is decreased, then residual aberration is reduced, but the amount of movement during focusing increases requiring more space
Solution Approach 1:
The lens system is divided into multiple lens units with different functions. The focus lens unit is separated from the zoom lens units, allowing independent optimization of focusing and zooming functions. This segmentation enables the focus lens unit to have high refractive power for reduced movement while aberrations are corrected by other lens units in the system.
3Speed
If the focus lens unit is made small and lightweight, then automatic focus speed is improved, but aberration control becomes more difficult
Solution Approach 1:
The lens system is divided into multiple lens units with different functions. The focus lens unit is separated from the zoom lens units, allowing independent optimization of focusing and zooming functions. This segmentation enables the focus lens unit to have high refractive power for reduced movement while aberrations are corrected by other lens units in the system.
Solution Approach 2:
The patent optimizes specific parameters of the lens units including refractive indices, focal lengths, and spacing relationships. By carefully controlling parameters such as the ratio of focal lengths and distances between lens units, the system achieves both fast focusing and aberration control.
4Volume of moving object
If the zoom lens is miniaturized, then overall size is reduced, but space for focus lens unit movement is constrained
Solution Approach 1:
The lens system is divided into multiple lens units with different functions. The focus lens unit is separated from the zoom lens units, allowing independent optimization of focusing and zooming functions. This segmentation enables the focus lens unit to have high refractive power for reduced movement while aberrations are corrected by other lens units in the system.
Solution Approach 2:
The patent optimizes specific parameters of the lens units including refractive indices, focal lengths, and spacing relationships. By carefully controlling parameters such as the ratio of focal lengths and distances between lens units, the system achieves both fast focusing and aberration control.
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 effectively decreases focusing movement, reduces aberration variation, and allows for the miniaturization of the zoom lens while maintaining excellent optical performance over full zoom and focus ranges, enabling a wide viewing angle and efficient zooming mechanism.
Implementation Method 1
a zoom lens includes a lens unit Ln having negative refractive power, a lens unit Lp1 having positive refractive power, and a lens unit Lp2 having positive refractive power
Data Source
AI summary
A zoom lens includes a lens unit Ln having negative refractive power including two or less lenses moving during focusing and zooming, a lens unit Lp1 having positive refractive power disposed adjacent to an object side thereof, and a lens unit Lp2 having positive refractive power disposed adjacent to an image side thereof. The lens units Lp1 and Lp2 move during zooming. A distance Tlw between a lens surface nearest to the object side in the entire zoom lens and an image plane at a wide-angle end, a distance Dnw between the lens surface nearest to the image side of the lens unit Ln and the image plane at the wide-angle end, a back focus bfw at the wide-angle end, and a maximum amount of movement Mnz during focusing of the lens unit Ln at a telephoto end are appropriately set.