Aspherical Fixed-Focus Lens Aberration Correction
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Solution Overview
Problem
Existing fixed-focus lens systems struggle to provide a balance between correcting various aberrations and maintaining a compact, cost-effective design with high image brightness, especially at wide angles of view, while also being challenging to manufacture due to complex optical configurations.
Innovation Solution
A fixed-focus lens system comprising a specific arrangement of meniscus and biconvex lens elements with aspherical surfaces, including a first lens with a convex surface having an inflection point off-axis, and a configuration that satisfies specific conditions for the shape factor and focal length ratios of the lens elements to correct aberrations and maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a complex optical configuration is used to correct various aberrations, then aberration correction performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies aspherical surfaces to the lens elements, particularly the first lens element which has an aspherical object-side surface. This curvature modification allows for effective correction of spherical aberration and other monochromatic aberrations without requiring additional lens elements, thereby maintaining manufacturing feasibility while improving optical performance
Solution Approach 2:
The patent optimizes specific parameter ranges for the lens system including the half angle of view (50 degrees or more), the focal lengths of individual lens elements, and the shape factors of lens surfaces. By carefully controlling these parameters within specified ranges, the system achieves good aberration correction with a manageable number of lens elements
2Area of moving object
If the angle of view is increased to 50 degrees or more, then field of view is improved, but aberration correction becomes more difficult
Solution Approach 1:
The patent divides the optical system into five distinct lens elements with alternating positive and negative powers. This segmentation allows each element to be optimized for specific aberration correction tasks while collectively handling the wide field of view requirements, making the overall system more manageable despite the 50-degree or greater half angle of view
Solution Approach 2:
The aspherical surface on the first lens element is particularly important for wide-angle performance. The aspherical curvature helps control off-axis rays and correct for distortion and astigmatism that become more pronounced at wider angles of view, enabling the system to maintain good image quality across the expanded field
3Manufacturing precision
If multiple lens elements are used to correct aberrations, then image quality is improved, but manufacturing cost increases
Solution Approach 1:
The patent uses exactly five lens elements, which is sufficient to achieve good aberration correction for a wide-angle fixed-focus system without being excessive. This partial action approach provides adequate correction for the primary aberrations (spherical, coma, astigmatism) while avoiding the need for more complex multi-element designs that would significantly increase manufacturing cost
Solution Approach 2:
The patent specifies particular parameter ranges for the lens elements including focal length ratios, shape factors, and material properties. By optimizing these parameters, the system achieves good image quality with a compact five-element design rather than requiring more elements, thereby reducing manufacturing complexity and cost while maintaining performance
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 lens system effectively corrects astigmatism and spherical aberrations across the imaging region, providing high image brightness and improved resolution performance while maintaining a compact size and reducing manufacturing complexity.
Implementation Method 1
a first lens element having negative power, the first lens element having a convex surface opposite to an object... A half angle of view of the fixed-focus lens system is 50 degrees or more, and a shape of the convex surface on the object side of the first lens element has at least one inflection point at a part except for an optical axis
Implementation Method 2
a fixed-focus lens system includes, in order from an object side to an image side, a first lens element having negative power... and a fifth lens element having positive power
Data Source
AI summary
A fixed-focus lens system includes, in order from an object side to an image side, a first lens element having negative power, the first lens element having a convex surface opposite to an object, a second lens element having positive power, the second lens element having a concave surface opposite to the object, a third lens element having positive power, a fourth lens element having negative power, and a fifth lens element having positive power. A half angle of view of the fixed-focus lens system is 50 degrees or more, and a shape of the convex surface on the object side of the first lens element has at least one inflection point at a part except for the optical axis. With this configuration, a fixed-focus lens system capable of favorably correcting various aberrations can be provided.