Four-Lens Image Pickup System with Aspherical Elements for Wide-Angle Aberration Control
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Solution Overview
Problem
Conventional image pickup lenses for vehicle and surveillance cameras face challenges in achieving a wide angle of view exceeding 180° while maintaining high optical performance, compactness, and cost-effectiveness, with existing lens systems often suffering from increased distortion and aberrations at wider angles.
Innovation Solution
A four-lens system comprising a meniscus lens with negative power, aspherical lenses with specific power and surface shapes, and strategically placed apertures, satisfying conditional expressions for focal lengths and surface curvatures to achieve a total angle of view greater than 200° with improved optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional lens systems are used to achieve a wide angle of view over 180°, then the angle of view requirement is met, but distortion and aberrations increase rapidly and significantly
Solution Approach 1:
The lens system is divided into four distinct lens elements with specific power distributions (first lens: negative power, second lens: negative power, third lens: positive power, fourth lens: positive power). This segmentation allows each lens to contribute to correcting specific aberrations while collectively achieving the wide angle of view over 180° with controlled distortion
Solution Approach 2:
The patent employs aspherical surfaces on the second, third, and fourth lenses to correct aberrations that spherical surfaces cannot address. The aspherical surfaces enable precise control of light rays at wide angles, reducing distortion and maintaining image quality across the entire imaging area while achieving the required angle of view
2Ease of manufacture
If the number of lenses is reduced to lower manufacturing cost, then cost-effectiveness is improved, but optical performance and aberration correction deteriorate
Solution Approach 1:
The patent optimizes specific parameter relationships between lens elements, expressed through conditional expressions (e.g., focal length ratios, curvature relationships). By precisely controlling these parameters within defined ranges, the four-lens system achieves high optical performance comparable to systems with more lenses, while maintaining cost-effectiveness through the reduced lens count
3Measurement precision
If image sensors are downsized with increased pixel counts to improve resolution, then imaging resolution is improved, but the requirement for wider angle of view and high optical performance becomes more difficult to satisfy
Solution Approach 1:
The aspherical surfaces on the second, third, and fourth lenses provide superior aberration correction compared to spherical surfaces, enabling the lens system to deliver high optical performance that matches the increased resolution capability of high-pixel-count image sensors. This allows compact sensor design without compromising overall system 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 solution enables a compact, inexpensive image pickup lens system with a wide angle of view and high optical performance, effectively correcting various aberrations and maintaining image quality across a wide range, suitable for applications requiring high-resolution imaging.
Implementation Method 1
a second lens having an aspherical surface on each of the object and image sides and a negative power adjacent to an optical axis
Implementation Method 2
a first lens which is a meniscus lens having a negative power and a concave surface on an image side
Data Source
AI summary
An image pickup lens having the following disposed from an object side in the order listed below: a first lens having a negative meniscus shape with a concave surface on an image side, a second lens having a negative meniscus shape with a concave surface on the object side adjacent to an optical axis, a third positive lens having a convex surface on the image side adjacent to the optical axis, an aperture, and a fourth lens having a bi-convex shape adjacent to the optical axis. Each of the second, third, and fourth lenses has an aspherical surface on each side.