Five-Lens Image Pickup Lens Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image pickup lenses with a five-lens configuration face challenges in achieving sufficient aberration correction and compactness, leading to performance deterioration and difficulty in accommodating larger pixel counts, while also being disadvantaged in downsizing due to insufficient spherical and comatic aberration correction.
Innovation Solution
The design incorporates a specific configuration of five lenses, including a first positive lens, a meniscus-shaped second negative lens, an aspheric third lens, a positive fourth lens, and a negative fifth lens, with aspheric surfaces and carefully controlled sag amounts, to achieve favorable aberration correction and telecentric characteristics, reducing the overall length while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a five-lens configuration is used to improve aberration correction, then image quality is improved, but the total length of the lens increases making it difficult to downsize
Solution Approach 1:
The patent applies parameter changes by optimizing the focal lengths, refractive indices, and curvature radii of the five lenses to achieve a balance between aberration correction and compact size. Specifically, the first lens has positive power with focal length f1, the second lens has negative power with focal length f2, and so on, with specific relationships between these parameters that enable both good aberration correction and reduced total length
Solution Approach 2:
The patent uses composite lens design combining different lens materials with specific refractive indices (nd) and Abbe numbers (νd). The first lens uses material with nd1 and νd1, the second lens uses material with nd2 and νd2, allowing optimization of both aberration correction and physical dimensions through material composition
2Length of moving object
If the total length of the lens is reduced for downsizing, then compactness is improved, but aberration correction becomes insufficient leading to performance deterioration
Solution Approach 1:
The patent segments the optical system into five distinct lens units with specific power distributions. The first lens (positive power) and second lens (negative power) form a telephoto-type front group, while the third, fourth, and fifth lenses form a rear group. This segmentation allows each lens to be optimized for specific aberration corrections while maintaining overall compactness
Solution Approach 2:
The patent employs aspheric surfaces on specific lens surfaces to correct spherical aberration and other monochromatic aberrations more effectively than spherical surfaces alone. The aspheric coefficients are optimized to achieve excellent aberration correction in the compact lens structure
3Ease of manufacture
If a spherical surface system is used for simplicity, then manufacturing is easier, but spherical aberration and comatic aberration cannot be corrected sufficiently
Solution Approach 1:
The patent introduces aspheric surfaces on the object-side surface of the first lens, image-side surface of the second lens, and image-side surface of the fifth lens. These aspheric surfaces are defined by specific mathematical equations with optimized coefficients that enable effective correction of spherical aberration and comatic aberration while remaining manufacturable with modern molding techniques
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
This configuration effectively corrects aberrations across the image plane, reduces the optical length, and enhances image quality, particularly on the periphery, while minimizing the impact of manufacturing errors and allowing for a more compact and lightweight image pickup apparatus.
Implementation Method 1
a third lens having an aspheric shape on the image side surface; and a fifth lens having a negative power and having a concave surface directed to the image side. Here, an image side surface of the fifth lens has an aspheric shape
Data Source
AI summary
An image pickup lens has a configuration of five lenses whose aberrations are corrected favorably despite its compactness compared to a conventional type.