Retrofocus Imaging Lens with Segmented Aberration Correction
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Solution Overview
Problem
Conventional wide-angle lenses with negative refractive power in the front lens group fail to achieve a balance between a wide angle of view and a large aperture, resulting in suboptimal optical performance.
Innovation Solution
A retrofocus-type imaging lens configuration with a first lens group including a negative meniscus lens and a double concave lens, combined with a second lens group having positive refractive power, and featuring at least six lens components, where the focal length and combined focal length of specific lens components satisfy specific conditional expressions to optimize power distribution and correct aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional retrofocus-type wide-angle lens configuration is used, then a wide angle of view is achieved, but the aperture cannot be made large enough and optical performance deteriorates
Solution Approach 1:
The lens is divided into multiple lens components (at least six) with different functions: negative meniscus lenses for wide angle of view, double concave lenses for aperture control, and positive meniscus lenses for focusing. This segmentation allows each component to be optimized for its specific function, enabling large aperture while maintaining optical performance.
Solution Approach 2:
Different lens components are positioned at specific locations with specific optical properties: the negative meniscus lens with convex surface facing object side is placed at the front to expand the angle of view, while positive meniscus lenses are positioned toward the image side for focusing. Each component has locally optimized characteristics that contribute to overall system performance.
2Reliability
If more lens components are added to improve optical performance, then aberration correction improves, but device complexity increases
Solution Approach 1:
The lens system is segmented into at least six functional components with specific arrangements: negative meniscus lenses (convex surface facing object side), double concave lenses, and positive meniscus lenses. This segmentation provides enough degrees of freedom to correct multiple types of aberrations while maintaining a manageable structure.
Solution Approach 2:
The patent specifies precise parameter ranges for each lens component including focal lengths (f1, f2, f3), curvature radii (r1, r2, r3), and spacing distances (d1, d2, d3). By controlling these parameters within defined ranges, the system achieves effective aberration correction without requiring excessive complexity.
3Illumination intensity
If the lens configuration is optimized for large aperture, then illumination intensity improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for lens components including focal lengths, curvature radii, and spacing distances. These parameter specifications provide clear manufacturing targets and tolerances, making it easier to achieve the required precision for large aperture designs without excessive 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
The configuration enables a fast, large-aperture, single-focal-length wide-angle lens with excellent optical performance, effectively correcting aberrations and maintaining optical precision while allowing for a downsized design.
Implementation Method 1
an aspherical surface formed by means of glass molding
Data Source
AI summary
An imaging lens SL installed in a single-lens reflex digital camera includes, in order from an object side, a first lens group G1, and a second lens group G2 having positive refractive power. The first lens group G1 includes, in order from the object side, a first lens component L11 having a negative meniscus shape with a convex surface facing the object side, a second lens component L12 having a negative meniscus shape with a convex surface facing the object side, and a third lens component L13. The third lens component L13 includes a double concave lens to the most object side. The imaging lens SL includes at least six lens components or more, thereby providing a sufficiently fast imaging lens having excellent optical performance, which is a large aperture, single-focal-length, wide-angle lens having an aspherical surface.