Zoom Lens Variable Stop Aberration Control
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Solution Overview
Problem
Conventional zoom lenses with constant minimum f-number during zooming experience significant spherical aberration variations, particularly at the telephoto end, due to large aperture diameter changes, which affect optical performance.
Innovation Solution
A zoom lens with a variable stop whose aperture diameter changes both during zooming and focusing, specifically increasing from the wide end to the telephoto end and decreasing from infinity to the minimum object distance, to maintain a constant minimum f-number and reduce spherical aberration variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the aperture diameter of the variable stop is increased to achieve a constant minimum f-number at the telephoto end, then the minimum f-number is maintained, but spherical aberration variation increases
Solution Approach 1:
The patent applies the dynamics principle by making the aperture stop diameter variable during focusing operations. The aperture stop diameter is dynamically adjusted based on the focus position (object distance) to compensate for spherical aberration variations. Specifically, the aperture stop diameter is reduced when focusing from infinity to the minimum object distance at the telephoto end, thereby reducing spherical aberration variation while maintaining the constant minimum f-number capability during zooming.
Solution Approach 2:
The patent applies the parameter changes principle by varying the aperture stop diameter as a controllable parameter during focusing. The diameter of the aperture stop is changed according to the focus position to optimize optical performance. This parameter adjustment allows the system to maintain a constant minimum f-number during zooming while reducing spherical aberration variation during focusing by appropriately controlling the aperture stop diameter.
2Illumination intensity
If the aperture diameter is kept large at the telephoto end for constant minimum f-number, then exposure is maintained, but aberration variations increase
Solution Approach 1:
The patent applies the dynamics principle by dynamically adjusting the aperture stop diameter based on both zoom position and focus position. During zooming, the aperture stop diameter is adjusted to maintain constant minimum f-number and proper exposure. During focusing at the telephoto end, the aperture stop diameter is reduced to minimize aberration variations. This dynamic control allows the system to balance exposure requirements with aberration control.
Solution Approach 2:
The patent applies the parameter changes principle by treating the aperture stop diameter as a variable parameter that is optimized for different operating conditions. The diameter is changed according to the combination of zoom position and focus position, allowing the system to maintain appropriate exposure levels while reducing aberration variations when necessary.
3Reliability
If a variable stop is used to maintain constant minimum f-number during zooming, then exposure consistency is improved, but device complexity increases
Solution Approach 1:
The patent applies the universality principle by designing the variable stop mechanism to perform multiple functions: maintaining constant minimum f-number during zooming and reducing spherical aberration variation during focusing. By making the aperture stop diameter controllable in both zooming and focusing operations, a single component achieves multiple optical optimization goals, thereby justifying the added complexity through enhanced functionality.
Solution Approach 2:
The patent applies the parameter changes principle by using a variable stop whose diameter can be adjusted according to different operational requirements. The diameter parameter is changed during zooming to maintain constant minimum f-number and during focusing to reduce spherical aberration variation. This parameter control capability allows the variable stop to address multiple optical performance issues with a single mechanism.
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 achieves a zoom lens with small aberration variations across the entire zoom and focus range, ensuring high optical performance by dynamically adjusting the aperture diameter based on zoom and focus positions.
Implementation Method 1
a variable stop whose aperture diameter is variable in zooming, the variable stop is a stop which determines a minimum f-number of the zoom lens
Data Source
AI summary
A zoom lens of the present invention is a zoom lens including a variable stop whose aperture diameter is variable in zooming, the variable stop is a stop which determines a minimum f-number of the zoom lens at least at one of zoom positions in an entire zoom range, and the aperture diameter of the variable stop is variable in focusing at least at a telephoto end in the entire zoom range.