Wide-Angle Lens System Aberration Control
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Solution Overview
Problem
Conventional wide-angle lens systems face challenges with image distortion, particularly at high field of views like 140 degrees, requiring numerous lens elements that increase system length and weight, and existing compensation methods often result in blurred peripheral images, which are unsuitable for applications like monitors and vehicle rearview systems.
Innovation Solution
A wide-angle lens system comprising four lens elements, including two negative meniscus elements and two biconvex elements with aspheric surfaces, arranged to minimize aberrations, with specific focal length and curvature relations to prevent extreme distortion and maintain image sharpness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional spherical glass lens elements are used to compensate for negative distortion aberration in wide-angle lens systems, then image distortion is corrected, but the number of lens elements increases to 8-12 pieces, which increases system length and weight
Solution Approach 1:
The patent applies aspheric surfaces on all lens elements to replace conventional spherical surfaces. The aspheric surfaces are defined by equations containing higher-order terms (4th, 6th, 8th, 10th order) that enable precise control of light rays, allowing single lens elements to achieve distortion correction that previously required multiple spherical elements. This reduces the total number of lens elements from 8-12 to just 4 pieces while maintaining correction effectiveness.
2Adaptability or versatility
If the field of view is increased to 140 degrees for wider monitoring coverage, then the monitoring area is expanded, but extreme image distortion occurs at the periphery making images unrecognizable
Solution Approach 1:
The patent employs multiple parameter changes including: (1) using plastic material with specific refractive indices (1.5356, 1.6323, 1.7222) instead of conventional glass; (2) implementing aspheric surface equations with multiple coefficients (K, A, B, C, D terms up to 10th order) to precisely control light paths; (3) optimizing specific focal length ratios (f123/f between -8.0 to -15.0, f123/f4 between -3.0 to -6.5) to balance the optical system. These parameter optimizations enable the system to achieve 140-degree field of view while maintaining image sharpness and preventing extreme peripheral distortion.
3Loss of information
If image processing technology is used to compensate for distortion, then some distortion correction is achieved, but the peripheral image remains blurred and unrecognizable
Solution Approach 1:
The patent replaces post-capture image processing methods with optical correction at the lens level. By incorporating aspheric surfaces with precisely calculated coefficients into the physical lens structure, the system corrects distortion optically before image formation. This ensures that light rays from peripheral fields are properly focused and directed, producing sharp, recognizable images without relying on digital processing that cannot recover lost peripheral detail.
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 system effectively compensates for aberrations with the least number of lens elements, ensuring high sharpness and preventing extreme image distortion even at 140 degrees field of view, making it suitable for monitor and vehicle-related applications.
Implementation Method 1
The first and second lens elements are negative meniscus lens elements with an object-side convex surface, and both of the third and fourth lens elements are biconvex. At least four of the surfaces of the first, second and third lens elements are aspheric surfaces, and both surfaces of the fourth lens element are aspheric.
Data Source
AI summary
A wide-angle lens system comprises, sequentially from the object side to the image side: a first lens element, a second lens element, a third lens element, an aperture and a fourth lens element. If the field of view of the wide-angle lens system is as high as 140 degrees, the extreme distortion of the image edge can be prevented with only four lens elements, and the image has a high sharpness. Therefore, it is very suitable for use in the monitor and vehicle-related lens system.