Imaging Lens System Aberration Control via Segmentation
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Solution Overview
Problem
Existing imaging lens systems for on-board and surveillance cameras lack performance in the near-infrared region, have high costs due to complex structures, and are prone to strong ghost images, especially in varying weather conditions and low illumination.
Innovation Solution
A compact and cost-effective imaging lens system with a negative meniscus lens and cemented lenses, optimized for a wide wavelength range with a long back focal length and small F number, featuring specific curvature and Abbe number conditions to minimize aberrations and ghost images, and incorporating a stop configuration to disperse reflected rays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a medium telephoto lens system with multiple lenses (7-8 lenses) is used, then aberration correction in the visible region is improved, but the lens system becomes large and high cost
Solution Approach 1:
The lens system is divided into only three lens groups (negative first lens, cemented lens, and stop), dramatically reducing the number of components from 7-8 lenses to just 3 groups while maintaining aberration correction capability through optimized design of each group
Solution Approach 2:
The cemented lens combines multiple lens elements into a single integrated component, reducing the total number of separate lenses and simplifying the overall system structure while maintaining optical performance
2Ease of manufacture
If a slow optical system with F number of about 4 is used, then manufacturing cost is reduced, but the lens is inappropriate for nighttime use
Solution Approach 1:
The F number is changed from the conventional value of about 4 to a smaller value, creating a fast optical system that can gather more light for nighttime use while maintaining manufacturability through the simplified three-group structure
3Measurement precision
If an aspheric surface lens is used, then optical performance is improved, but required precision at cutting and assembly becomes higher and cost increases
Solution Approach 1:
Aspheric surfaces are applied only to specific critical surfaces where they provide the most benefit, rather than to all lens surfaces, thereby maintaining optical performance while reducing manufacturing complexity and cost
4Volume of moving object
If a compact lens system is used, then device size is reduced, but back focal length becomes short
Solution Approach 1:
The optical design utilizes strategic positioning of the stop and curvature relationships in the cardinal points to achieve a long back focal length in a compact overall structure, effectively decoupling these two parameters through clever geometric arrangement
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 provides a high-performance optical system with reduced ghost image intensity and lower production costs, maintaining excellent performance across visible and near-infrared regions, suitable for diverse weather conditions and low-light scenarios.
Implementation Method 1
a negative first lens L1, a cemented lens LC... The negative first lens is disposed on a most object side, has a concave surface directed toward the object side and has a meniscus shape
Implementation Method 2
The cemented lens is disposed on a most image side. A most object side surface of the cemented lens is a convex surface
Implementation Method 3
The stop is disposed just in front of the object side of the cemented lens... incorporating a stop configuration to disperse reflected rays
Data Source
AI summary
The imaging lens system includes a negative first lens disposed on a most object side, having a concave surface directed toward the object side and having a meniscus shape, a cemented lens LC disposed on a most image side and having a convex surface on its most object side, and an aperture diaphragm disposed just in front of the object side of the cemented lens. The system satisfies the following conditional expressions:0.05<(R2−R1)/(R1+R2)<0.25vd1 −vd2 >15whereR1 and R2 denote radius of curvatures of object side and image side surfaces of the first lens, respectively, andvd1 and vd2 denote Abbe numbers of lenses, which are located on the most object side and on the most image side among lenses constituting the cemented lens, at the d-line, respectively.