Imaging Lens Segmentation for High-Speed Focusing
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Solution Overview
Problem
Existing imaging lenses with wide photographing fields and low F numbers face challenges in miniaturization and high-speed focusing due to heavy lens groups and large actuators required for rapid movement during video recording, leading to increased lens tube size.
Innovation Solution
The proposed imaging lens configuration includes a fixed first lens group with negative refractive power, a second lens group with positive refractive power, a stop, a third cemented lens group, a fourth positive lens group, a fifth focus group with a single negative lens, and a sixth positive lens group, where specific surface curvatures and aspheric surfaces are used to minimize aberrations and reduce the weight of the focus group, allowing for high-speed focusing while maintaining miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the entire lens system or a heavy lens group is moved at high speed to photograph moving images, then focusing speed is improved, but lens tube size increases due to heavy weight and large actuator
Solution Approach 1:
The lens system is divided into multiple lens groups with different refractive powers. The focusing function is assigned to a specific lens group (the second lens group with positive refractive power) that can be moved independently, rather than moving the entire lens system. This segmentation allows for a lighter focusing component while maintaining the ability to achieve high-speed focusing.
Solution Approach 2:
Different lens groups are assigned different functions: the first lens group (negative refractive power) handles aberration correction, the second lens group (positive refractive power) handles focusing, and subsequent groups handle additional aberration correction and image quality optimization. This local functional assignment allows the focusing component to be optimized for speed while other groups optimize for quality.
2Reliability
If a lens group with heavy weight is used for focusing, then focusing capability is improved, but device complexity increases due to larger actuator requirements
Solution Approach 1:
The lens system is segmented into functional modules where the second lens group is specifically designated for focusing. This allows the actuator to only need to move this specific group rather than supporting the entire lens system, thereby reducing actuator size and device complexity while maintaining reliable focusing capability.
Solution Approach 2:
The refractive power parameters of different lens groups are optimized to achieve the required focusing performance. By assigning positive refractive power to the movable second lens group and negative refractive power to the first group, the system achieves effective focusing with reduced mechanical complexity.
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 effectively suppresses spherical aberration and miniaturizes the lens tube by reducing the weight of the focus group, enabling high-speed and precise focusing while maintaining excellent image quality and reducing the overall optical length.
Implementation Method 1
a third lens group including a cemented lens... a chromatic aberration is corrected by the cemented lens of the third lens group
Implementation Method 2
at least one surface of the positive lens of the fourth lens group may be aspheric... a spherical aberration is corrected by the aspheric surface of the positive lens
Implementation Method 3
an imaging lens which includes a first lens group having a negative refractive power and a second lens group having a positive refractive power... arranged sequentially from an object side to an image side
Data Source
AI summary
Provided is an imaging lens including a fixed first lens group having a negative refractive power, a second lens group having a positive refractive power, a stop, a third lens group including a cemented lens, a fourth lens group including a positive lens, a fifth lens group serving as a focus group and including a negative lens, and a sixth lens group including a positive lens that are arranged sequentially from an object side to an image side.