Plastic Aspheric Imaging Lens for 180-Degree Field of View
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Solution Overview
Problem
Conventional imaging lenses for compact image pickup devices, such as in-vehicle cameras and home appliances, face challenges in achieving a wide field of view with high optical performance while being compact and cost-effective, as they often require multiple lenses and materials that are difficult to manufacture, leading to high production costs and aberration issues.
Innovation Solution
A compact imaging lens configuration with four lenses, where the first and second lenses are made of plastic with specific aspheric surfaces to minimize aberrations, and the third and fourth lenses, also made of plastic, correct various optical errors, ensuring a wide field of view and high optical performance within a compact form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple glass lenses and cemented lenses are used to achieve high optical performance and wide field of view, then imaging quality is improved, but manufacturing cost increases and device complexity increases
Solution Approach 1:
The patent changes the material parameter from glass to plastic for the first and second lenses, and modifies the surface shape parameter by introducing aspheric surfaces. This allows achieving wide field of view and high optical performance with only four lenses, reducing device complexity while maintaining imaging quality
Solution Approach 2:
The patent uses composite material strategy by combining plastic material with aspheric surface design for the first and second lenses, and plastic material with spherical or aspheric surfaces for the third and fourth lenses. This composite approach enables compact structure with high optical performance
2Reliability
If multiple glass lenses and cemented lenses are used to achieve high optical performance, then imaging quality is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the material parameter from glass to plastic for the first and second lenses, which are easier and cheaper to manufacture. The aspheric surface design is implemented through plastic molding processes, significantly reducing manufacturing cost while maintaining high optical performance
Solution Approach 2:
The patent replaces expensive glass lenses with cheaper plastic lenses that can be manufactured at lower cost through injection molding processes, making the overall lens system more cost-effective
3Device complexity
If a compact lens structure is used to reduce device size, then device complexity is reduced, but achieving wide field of view and high optical performance becomes difficult
Solution Approach 1:
The patent applies aspheric surfaces to the first and second lenses, which have curved non-spherical shapes. This allows the compact four-lens structure to correct optical aberrations effectively and achieve wide field of view with high imaging performance
Solution Approach 2:
The patent modifies the surface shape parameter by introducing aspheric surfaces and optimizes the focal length ratios, enabling a compact four-lens structure to achieve wide field of view and high optical performance that would normally require more lenses
4Ease of manufacture
If plastic material is used for the first lens to reduce manufacturing cost, then ease of manufacture is improved, but manufacturing precision becomes difficult to achieve
Solution Approach 1:
The patent employs aspheric surfaces for the first and second lenses made of plastic material. The aspheric design, when combined with precision injection molding techniques, enables manufacturing of complex curved surfaces with high accuracy, resolving the trade-off between ease of manufacture and manufacturing precision
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 configuration achieves a wide field of view of about 180 degrees with high optical performance and compactness, reducing manufacturing costs and aberrations, making it suitable for low-priced imaging applications in various devices.
Implementation Method 1
a first lens with negative refractive power having a convex surface on the object side and an aspheric surface on the image side; a second lens with negative refractive power as a double-sided aspheric lens having a concave surface on the image side
Data Source
AI summary
A compact low-priced imaging lens which offers a field of view of about 180 degrees and high optical performance. The imaging lens for a solid-state image sensor includes, in order from an object side to an image side, a first lens with negative refractive power having a convex object-side surface and an aspheric image-side surface; a second lens with negative refractive power as a double-sided aspheric lens having a concave surface on the image side; a third lens with positive refractive power; an aperture stop; and a fourth lens with positive refractive power. The first and second lenses are made of plastic material. The imaging lens satisfies conditional expressions (1) and (2) below:−65.0<f1/f<−17.0 (1)0.04<f2/f1<0.14 (2)wheref: focal length of the overall optical system of the imaging lensf1: focal length of the first lensf2: focal length of the second lens.