Zoom Lens Design with Segmented First Unit for Large Aperture
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving a high optical performance over the entire zoom range while maintaining a large aperture diameter and minimizing size and weight, especially when dealing with large sensor formats like Super 35 and full frame formats.
Innovation Solution
The zoom lens design incorporates a first lens unit with a positive refractive power that remains fixed during zooming, accompanied by movable lens units with negative refractive power, and a final lens unit with positive refractive power, optimizing the focal lengths and lateral magnifications to reduce the thickness and diameter of the first lens unit, thereby achieving a larger aperture diameter and high optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the first lens unit is made thicker to increase aperture diameter, then the aperture diameter increases, but the overall zoom lens size increases
Solution Approach 1:
The first lens unit is divided into multiple subunits (first subunit with negative refractive power, second subunit with negative refractive power, and third subunit with positive refractive power) that can move independently during focusing. This segmentation allows each subunit to be optimized for its specific function, enabling the first lens unit to achieve the required aperture diameter while reducing overall thickness through coordinated movement of the subunits.
Solution Approach 2:
The patent implements a dynamic focusing mechanism where the first, second, and third subunits move along the optical axis in a coordinated manner during focusing. The first subunit moves in the first direction, the second subunit moves in the second direction, and the third subunit moves in the third direction. This dynamic arrangement allows the lens unit to maintain optimal optical characteristics across different focus distances while minimizing the maximum thickness required.
2Illumination intensity
If the first lens unit is made thicker to increase aperture diameter, then the aperture diameter increases, but the weight increases
Solution Approach 1:
By segmenting the first lens unit into multiple subunits with different refractive powers, the patent distributes the optical function across smaller, lighter components rather than requiring a single thick lens element. This segmentation reduces the total weight while maintaining the required aperture diameter.
Solution Approach 2:
The dynamic movement of subunits during focusing allows the lens to achieve the required aperture diameter at the widest point without maintaining that thickness throughout the entire lens structure. The subunits move to optimize the effective aperture at different focus distances, reducing the average weight compared to a static thick lens design.
3Illumination intensity
If the first lens unit is made thicker to increase aperture diameter, then the aperture diameter increases, but the optical performance deteriorates due to increased aberrations
Solution Approach 1:
The first lens unit is segmented into multiple subunits with different refractive powers (negative, negative, and positive) that can move independently. This segmentation allows for better control and correction of optical aberrations by distributing the refractive function across multiple elements, each contributing to the overall optical performance while maintaining a large effective aperture diameter.
Solution Approach 2:
The patent utilizes the movement of subunits along the optical axis to dynamically change the optical parameters of the lens system during focusing. By adjusting the positions of the first, second, and third subunits, the lens maintains optimal focus and minimizes aberrations across different object distances while preserving the large aperture diameter capability.
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 results in a small, lightweight zoom lens with a large aperture diameter and high optical performance across the entire zoom range, effectively addressing the size and weight constraints while maintaining high image quality.
Implementation Method 1
a first lens unit L1 having a positive refractive power; a plurality of zooming lens units having a negative refractive power configured to move along the optical axis during zooming
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3A~3B
AI summary
A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a plurality of zooming lens units configured to move along an optical axis in zooming and including a lens unit having a negative refractive power, and a final lens unit having a positive refractive power. A distance between each pair of adjacent lens units changes in zooming. The first lens unit includes, in order from the object side to the image side, a first subunit having a negative refractive power, a second subunit having a negative refractive power, and at least one subsequent subunit, a distance between each pair of adjacent subunits changing for focusing. The second subunit is configured to move along the optical axis for focusing. A predetermined condition is satisfied.