Bi-aspherical Plastic Imaging Lens for Vehicle Cameras
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Solution Overview
Problem
Existing imaging lenses for vehicles and surveillance cameras are insufficient in miniaturization, cost-effectiveness, and brightness, with high refractive index glass lenses being costly and F-number lenses being too dark for adequate brightness in low-light environments.
Innovation Solution
An imaging lens configuration comprising a negative meniscus first lens, a positive aspherical second lens, and a positive aspherical third lens with an aperture diaphragm between the second and third lenses, optimized by specific focal length and Abbe number ratios to achieve miniaturization, wide field angles, and improved image quality, while using bi-aspherical plastic lenses to reduce weight and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-refractive index glass is used for the first lens, then excellent optical performance is achieved, but the cost increases significantly
Solution Approach 1:
The patent changes the material parameter from high-refractive index glass to plastic with refractive index 1.50869 or higher, and modifies the surface shape parameter by introducing aspherical surfaces. This combination allows achieving the required optical performance while significantly reducing manufacturing cost and enabling mass production through injection molding techniques.
Solution Approach 2:
The patent replaces expensive glass lenses with cheaper plastic lenses that can be manufactured through injection molding. While plastic may have different durability characteristics, it provides cost-effective solution for applications where mass production is required, such as vehicle cameras and surveillance systems.
2Ease of manufacture
If the F-number is increased to 3.8 or more, then manufacturing is simplified, but the image becomes dark and unsuitable for low-light environments
Solution Approach 1:
The patent optimizes the F-number parameter to be 2.6 or higher but less than 3.8, finding the optimal balance between manufacturing feasibility and image brightness. This parameter range allows adequate light transmission for low-light performance while maintaining reasonable manufacturing complexity through standard injection molding processes.
3Reliability
If existing imaging lens configurations are used, then optical performance is maintained, but miniaturization is insufficient
Solution Approach 1:
The patent divides the imaging lens into three distinct lens units with specific focal length relationships (|f2/f3| between 0.2-0.6 and |f1/f23| between 0.1-0.4). This segmentation allows each lens to be optimized for its specific function while maintaining compact overall dimensions, achieving miniaturization without sacrificing optical performance.
Solution Approach 2:
The patent introduces aspherical surfaces on one or both sides of the first lens and on the second lens to correct aberrations more effectively than spherical surfaces. This allows for shorter focal lengths and more compact lens designs while maintaining high image quality across the field of view.
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 an imaging lens with an F-number of 2.8, sufficient curvature correction, and a wide diagonal field angle of 90 degrees or more, suitable for vehicle and surveillance cameras, while maintaining reduced size and high performance.
Implementation Method 1
a second lens having at least one aspherical surface; and a third lens of a positive lens having a convex surface on the image side and having at least one aspherical surface
Implementation Method 2
An aperture diaphragm is disposed between the second lens and the third lens
Data Source
AI summary
An imaging lens is configured sequentially from the object side by: a first lens having a meniscus shape where a convex surface is directed to the object side; a second lens; and a positive third lens in which an image-side surface is a convex surface. The first lens, the second lens, and the third lens are configured by a bi-aspherical plastic lens. The second lens is configured by a bi-convex lens in which the absolute value of the radius of curvature of the object-side surface is smaller than that of the image-side surface. The third lens is a positive lens and a meniscus lens in which a concave surface is directed to the object side, and a convex surface is directed to the image side.