Wide-Angle Imaging Lens Design for Onboard Cameras
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wide-angle imaging lenses for onboard and surveillance cameras are either too expensive due to high refractive index glass materials, insufficiently wide-angle, or have poor optical performance, and lack weather resistance across a wide temperature range.
Innovation Solution
A compact, five-grouped six-lens imaging lens configuration using a negative first lens, a negative second lens, a biconvex third lens, a stop, a positive fourth lens, and a cemented lens with specific refractive index and Abbe number conditions to achieve a wide angle, balanced chromatic aberration, and weather resistance, while minimizing size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high refractive index glass materials (N>1.9) are used to achieve a bright lens with F number of 2, then the lens becomes expensive, but cost reduction is needed
Solution Approach 1:
The patent changes the optical parameters by using glass materials with refractive indices within specific ranges (1.50<N1≤1.85, 1.50<N2≤1.85, 1.60<N3≤1.90, 1.60<N4≤1.90) rather than requiring high refractive index materials (N>1.9). This parameter optimization allows achieving F number of 2.0 or smaller while using cost-effective glass materials, resolving the contradiction between brightness and manufacturing cost
Solution Approach 2:
The patent employs a composite lens structure with five lens groups (six lenses total) where each lens is made of different glass materials with specifically controlled refractive indices and Abbe numbers. The cemented lens structure combines lenses with complementary optical properties to achieve the desired F number and chromatic aberration correction without requiring expensive high-refractive-index materials throughout the entire system
2Ease of manufacture
If a simple five-grouped six-lens configuration is used to reduce cost, then optical performance and aberration correction become insufficient, but high performance is needed
Solution Approach 1:
The patent applies local quality by assigning specific optical properties to specific lens positions within the five-grouped six-lens configuration. Each lens group has deliberately chosen refractive indices and Abbe numbers tailored to its position and function: the first and second lens groups use materials with N>1.50 for wide-angle correction, the third lens group uses N>1.60 for chromatic aberration control near the stop, and the fourth and fifth lens groups use materials optimized for their specific aberration correction needs. This localized optimization enables a simple six-lens structure to achieve superior optical performance
3Volume of moving object
If glass materials with high refractive index are used to achieve compact size, then the lens becomes expensive, but miniaturization is sought
Solution Approach 1:
The patent achieves miniaturization without high costs by optimizing the parameters of standard glass materials rather than using exotic high-refractive-index materials. The conditional expressions for refractive indices (1.50<N1≤1.85, 1.50<N2≤1.85, 1.60<N3≤1.90, 1.60<N4≤1.90) and Abbe numbers are carefully selected to maximize the optical power per unit thickness, enabling a compact form factor with conventional, cost-effective glass materials
4Adaptability or versatility
If a wide-angle design is implemented to meet surveillance requirements, then chromatic aberration and other aberrations increase, but optical quality must be maintained
Solution Approach 1:
The patent controls chromatic and other aberrations in the wide-angle design by precisely controlling the refractive index and Abbe number parameters of each lens material. The conditional expressions ensure that the third lens group (with 1.60<N3≤1.90 and ν3≥30) and fourth lens group (with 1.60<N4≤1.90 and ν4≥30) provide sufficient chromatic aberration correction, while the first and second lens groups (with N>1.50) handle the wide-angle field curvature and distortion. This parameter-based approach maintains optical quality across the wide 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 provides a compact, bright, inexpensive, and high-performance wide-angle imaging lens suitable for various environmental conditions, with improved optical performance and reduced chromatic aberration, suitable for applications like onboard cameras.
Implementation Method 1
a third biconvex lens; a stop; a fourth lens whose surface having a smaller absolute value of radius of curvature is directed toward the image side, the fourth lens having a positive refractive power
Implementation Method 2
a cemented lens having a positive refractive power, the cemented lens including a fifth lens and a sixth lens, the fifth lens having a positive refractive power and having a biconvex shape, the sixth lens having a negative refractive power and having a meniscus shape
Implementation Method 3
Balanced chromatic aberration is achieved by arranging, on the image surface side, the cemented lens consisting of the negative lens and the positive lens
Data Source
AI summary
The imaging lens is provided and includes: in order from the object side, a negative first lens whose concave surface is directed toward the image side; a second lens of a planoconcave lens whose flat surface is directed toward the object side or a biconcave lens whose surface having a larger absolute value of radius of curvature is directed toward the object side; a third biconvex lens; a stop; a positive fourth lens whose surface having a smaller absolute value of radius of curvature is directed toward the image side; and a cemented lens of a positive fifth lens of biconvex shape and a negative sixth lens of meniscus shape, the cemented lens having a positive refractive power, and an Abbe number ν3 at d-line of the third lens satisfies a conditional expression (1) ν3<43.