Asymmetric Imaging Lens Aberration Correction
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Solution Overview
Problem
Existing imaging lenses, such as double-Gauss type lenses, inadequately correct spherical and comatic aberrations, particularly off-axis comatic aberration, due to insufficient lens configurations between the image side and aperture stop.
Innovation Solution
An imaging lens configuration with a first lens group and a second lens group, where the second lens group is composed of at least two negative lenses and three positive lenses, with a specific focal length ratio and including aspherical lenses, to adjust refractive powers and correct various aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional large-aperture standard lens configuration (one negative lens and three positive lenses between image side and aperture stop) is used, then the device complexity is reduced, but the correction of spherical aberration and comatic aberration is insufficient
Solution Approach 1:
The patent changes the lens configuration parameters by increasing the number of lenses from 4 to 5 in the second lens group, specifically adding another positive lens. This parameter change enables better correction of spherical and comatic aberrations while maintaining the overall system structure.
Solution Approach 2:
The patent divides the lens system into two distinct lens groups: a first lens group with positive refractive power and a second lens group with positive refractive power containing at least two negative lenses and three positive lenses. This segmentation allows independent optimization of each group for aberration correction.
2Reliability
If the number of lenses in the second lens group is increased to improve aberration correction, then the imaging performance is improved, but the manufacturing cost and assembly complexity increase
Solution Approach 1:
By dividing the lens system into two functional groups with distinct roles, the patent enables modular manufacturing and assembly. The first lens group handles primary focusing while the second lens group specializes in aberration correction, simplifying the manufacturing process despite the increased number of elements.
Solution Approach 2:
The patent optimizes the distribution of lens elements by specifying that the second lens group contains at least two negative lenses and three positive lenses, creating a balanced configuration that improves imaging performance while managing manufacturing complexity through systematic arrangement.
3Illumination intensity
If a symmetric double-Gauss lens configuration is used, then the aperture is enlarged, but the correction of off-axis comatic aberration remains insufficient
Solution Approach 1:
The patent breaks the symmetric double-Gauss configuration by creating an asymmetric second lens group with a specific arrangement of at least two negative lenses and three positive lenses. This asymmetric design effectively corrects off-axis comatic aberration while preserving the large aperture capability of the original double-Gauss structure.
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 proposed configuration effectively corrects comatic aberration, spherical aberration, and field curvature, ensuring favorable imaging performance at infinity with reduced sensitivity and simplified assembly.
Implementation Method 1
at least one aspherical lens is included in the second lens group
Implementation Method 2
effective correction of comatic aberration, spherical aberration, and field curvature
Implementation Method 3
effective correction of comatic aberration, spherical aberration, and field curvature
Data Source
AI summary
An imaging lens satisfies the following conditional expression (1) and is configured by disposing a first lens group that has a positive refractive power, an aperture stop, and a second lens group that has a positive refractive power in order from an object side to an image side. The first and second lens groups are moved from the image side to the object side in a state in which a gap between the lens groups is constant on an optical axis when a subject distance changes from infinity to approach, and the second lens group is configured by at least two negative lenses and at least three positive lenses.0.01<f2/f1<0.23 (1)where,f1: focal length of the first lens group when focused on an object at infinityf2: focal length of the second lens group when focused on an object at infinity.