Wide-Angle Optical System Aberration Control via Lens Curvature Ratios
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wide-angle optical systems face challenges in achieving a large angle of view while maintaining low aberrations, particularly astigmatism, coma, and spherical aberration, due to limitations in lens design and refractive power distribution.
Innovation Solution
The proposed wide-angle optical system consists of a specific arrangement of lenses with negative and positive refractive powers, including a first lens with a convex object-side surface, an aperture stop, and conditional expressions that optimize the radii of curvature and distances between lens elements to suppress aberrations and enhance the angle of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a wide angle of view is achieved using conventional lens arrangements, then the angle of view increases, but off-axis aberrations (astigmatism, coma, spherical aberration) increase
Solution Approach 1:
The optical system is divided into five distinct lens units with specific refractive powers arranged in a particular sequence. The front unit (L1-L3) and rear unit (L4-L5) are segmented to independently address different aberration types, allowing the wide angle of view to be achieved while maintaining aberration control through coordinated design of each segment.
Solution Approach 2:
Each lens element is designed with specific local properties: L1 has a convex object-side surface with controlled curvature ratio, L2 and L5 have negative refractive powers positioned at specific locations, and L3 and L4 have positive refractive powers. These localized quality variations enable different regions of the optical system to correct different types of off-axis aberrations while maintaining the wide angle of view.
2Illumination intensity
If the F-number is reduced to improve light gathering capability, then illumination intensity increases, but aberrations become more difficult to control
Solution Approach 1:
The optical system employs specific parameter ranges for lens curvatures and spacing to achieve both low F-number and aberration control. The conditional expressions define optimal parameter ranges: the curvature ratio of L1's object-side surface (1.0≤(R1L+R1R)/(R1L−R1R)≤2.0), the spacing ratio between L3 and L4 (1.7≤D34/FL≤7.0), and the curvature ratios of L3 and L5 ensure that light gathering capability is maximized while aberrations remain controlled even at small F-numbers.
3Volume of moving object
If lens curvatures are increased to achieve wider angle of view, then the angle of view increases, but spherical aberration and coma increase
Solution Approach 1:
The optical system uses asymmetric lens designs where the object-side surface of L1 is convex with a controlled curvature ratio that differs from other lens surfaces. The alternating pattern of negative and positive refractive powers in the lens sequence (L1: negative, L2: negative, L3: positive, L4: positive, L5: negative) creates an asymmetric power distribution that effectively corrects spherical aberration and coma while maintaining the wide angle of view.
4Manufacturing precision
If multiple lens elements are added to correct aberrations, then aberration control improves, but device complexity increases
Solution Approach 1:
Each lens element in the five-element system serves multiple functions simultaneously. For example, L2 with negative refractive power not only corrects spherical aberration but also contributes to coma correction and maintains the wide angle of view. The aperture stop positioned between L3 and L4 serves both as an aberration control element and a definition of the entrance pupil. This multi-functionality reduces the need for additional dedicated correction elements, maintaining relatively simple device complexity while achieving effective aberration control.
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 allows for a wide angle of view of up to 220° with a small F-number, effectively suppressing off-axis aberrations and maintaining high image resolution, suitable for applications like capsule endoscopes and car-mounted cameras.
Implementation Method 1
a first lens having a negative refractive power, an object-side surface of which is convex toward the object side
Implementation Method 2
a second lens having a negative refractive power, a third lens having a positive refractive power, a fourth lens having a positive refractive power, and a fifth lens having a negative refractive power
Data Source
AI summary
A wide-angle optical system includes in order from an object side to an image side, a first lens having a negative refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, an aperture stop, a fourth lens having a positive refractive power, and a fifth lens. An object-side surface of the first lens is convex toward the object side, and the following conditional expression (1) is satisfied.1.0<(R1L+R1R)/(R1L−R1R)≤2.0 (1)where,R1L denotes a paraxial radius of curvature of the object-side surface of the first lens, andR1R denotes a paraxial radius of curvature of an image-side surface of the first lens.