Imaging Lens Abbe Number Control for Chromatic Aberration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing imaging lenses for in-vehicle and monitoring cameras have limitations in achieving a wide angle of view, small size, low manufacturing cost, and high optical performance, particularly requiring a small F number and weather resistance across varying temperatures.
Innovation Solution
The design of an imaging lens with a specific configuration of six lenses, including a negative power first lens, positive power second lens, biconcave fourth lens, and positive power fifth and sixth lenses, optimized by controlling curvature radii and Abbe numbers to achieve a wide angle of view, small size, and low manufacturing cost, while minimizing chromatic aberration and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an aspheric lens is used to reduce F number, then optical performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the optical parameters by selecting specific Abbe numbers for lens materials (ν2 ≥ 45 for positive lenses, ν4 ≤ 30 for negative lenses) and controlling curvature radii ratios to achieve the desired F number and angle of view without requiring aspheric surfaces, thus maintaining spherical lens manufacturability while optimizing optical performance
Solution Approach 2:
The patent uses composite lens structures with different material properties, combining positive and negative power lenses with specific Abbe number combinations to correct chromatic aberration and achieve the target F number through material selection rather than complex surface shaping
2Illumination intensity
If the F number is reduced for night use, then light gathering capability is improved, but chromatic aberration increases
Solution Approach 1:
The patent changes material parameters by selecting lenses with specific Abbe numbers (ν2 ≥ 45, ν4 ≤ 30) to control dispersion characteristics, enabling the system to achieve low F number while maintaining chromatic aberration correction through appropriate material combinations
Solution Approach 2:
The patent introduces intermediate lenses (positive second lens and negative fourth lens) that act as mediators to correct chromatic aberration generated by the overall optical system, with the fourth lens specifically designed to counteract chromatic effects while the positive lenses provide the necessary converging power for low F number
3Adaptability or versatility
If the angle of view is increased for monitoring coverage, then field of view is improved, but distortion increases
Solution Approach 1:
The patent controls the ratio of curvature radii (|R3|/R4 between 0.3-1.5 and |R6|/R7 between 0.3-1.5) to optimize the balance between angle of view and distortion, allowing wide monitoring coverage while maintaining image geometric accuracy through precise surface curvature relationships
Solution Approach 2:
The patent segments the optical system into multiple functional lens groups (first negative lens for field curvature control, second positive lens for chromatic aberration correction, fourth negative lens for distortion correction) that work together to achieve wide angle of view with minimized distortion
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 a wide angle of view, small size, low manufacturing cost, and high optical performance, effectively correcting chromatic aberration and distortion, suitable for use in in-vehicle and monitoring cameras across a wide temperature range.
Implementation Method 1
an imaging lens includes: a first lens L1 that has a negative power and includes a concave surface facing an image side, a second lens L2 having a positive power, a third lens L3 having a positive power, an aperture diaphragm St, a fourth lens L4 that is a biconcave lens having a negative power, a fifth lens L5 that has a positive power and includes a convex surface facing the image side, and a sixth lens L6 that has a positive power and includes a convex surface facing an object side
Data Source
AI summary
An imaging lens includes a first lens having a negative power and including a concave surface facing an image side, a second lens having a positive power, a third lens having a positive power, an aperture diaphragm, a fourth lens, which is a biconvex lens having a negative power, a fifth lens having a positive power and including a convex surface facing the image side, and a sixth lens having a positive power and including a convex surface facing an object side, which are arranged in this order from the object side. The Abbe number of a material forming the fourth lens with respect to the d-line is 30 or less. When the focal length of the entire lens system is f and a composite focal length from the fourth lens to the sixth lens is f456, the imaging lens satisfies following conditional expression:1.00<f456/f<1.88.