Five-Element Imaging Lens Aberration Correction via Aspheric Curvature
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Solution Overview
Problem
Conventional imaging lenses with fewer elements, such as four lenses, struggle to correct aberrations effectively for high-pixel demands, while five-lens systems with large diameters and high performance have a high telephoto ratio and increased manufacturing costs.
Innovation Solution
A five-element imaging lens configuration with specific refractive power arrangements and aspheric surfaces, including a first lens with positive refractive power, a second lens with negative refractive power, a third lens with convex surfaces, a fourth lens with convex surfaces, and an aberration correction optical element with flat and aspheric surfaces, optimized to reduce total track length and correct aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a five-lens system is used to correct aberrations for high-pixel demands, then aberration correction performance is improved, but the telephoto ratio becomes too large and manufacturing cost increases
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive powers and curvature radii of the five optical elements to achieve a balanced configuration. Specifically, the first optical element has positive refractive power with curvature radius ratio r1/r2 between 0.05 and 0.30, the second has negative refractive power with r3/r4 between 0.60 and 1.50, and the fourth has positive refractive power with r7/r8 between 0.20 and 1.00. These parameter optimizations enable effective aberration correction while maintaining a reduced telephoto ratio compared to conventional five-lens systems
Solution Approach 2:
The patent utilizes aspheric surfaces on multiple optical elements to correct aberrations more effectively. The first, second, third, and fourth optical elements all incorporate aspheric surfaces with specific curvature characteristics. This application of curved surface geometry enables superior aberration correction performance while allowing for a more compact overall lens configuration, thereby reducing the telephoto ratio
2Manufacturing precision
If a five-lens system is used to correct aberrations for high-pixel demands, then aberration correction performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent optimizes manufacturing parameters by specifying precise curvature radius ratios and refractive power relationships that balance performance and manufacturability. The curvature radius ratios (r1/r2: 0.05-0.30, r3/r4: 0.60-1.50, r7/r8: 0.20-1.00) and spacing relationships (d1/d2: 0.30-1.50, d3/d4: 0.20-0.80, d5/d6: 0.10-0.50) are designed to be achievable through standard manufacturing processes while delivering high aberration correction performance for mass production
Solution Approach 2:
The patent divides the optical system into five distinct optical elements, each with specific functions and characteristics. This segmentation allows for optimized correction of different types of aberrations (spherical, coma, astigmatism, field curvature, distortion) while enabling modular manufacturing and assembly, thereby controlling manufacturing costs through standardized production of individual elements
3Device complexity
If fewer lenses (four lenses) are used, then device complexity is reduced, but aberration correction capability becomes insufficient for high-pixel demands
Solution Approach 1:
The patent employs aspheric surfaces on all five optical elements to maximize aberration correction capability. The aspheric surface parameters are optimized to correct spherical aberration, coma, and other higher-order aberrations that cannot be adequately corrected by spherical surfaces alone. This enables the lens system to achieve the required performance for high-pixel sensors while maintaining a relatively simple five-element configuration
Solution Approach 2:
The patent utilizes sophisticated parameter optimization including refractive indices (1.50<Nd<1.70 for first element, 1.40<Nd<1.60 for second element), curvature radius ratios, and spacing relationships to achieve superior aberration correction. These parameter changes enable the five-element system to outperform conventional four-element systems in correcting chromatic and monochromatic aberrations
4Length of moving object
If the total track length is reduced for compact size, then device profile is improved, but aberration correction becomes more difficult
Solution Approach 1:
The patent uses aspheric surfaces on multiple optical elements to achieve effective aberration correction within a compact total track length. The aspheric surface parameters are specifically optimized to correct aberrations that would normally require longer optical paths, enabling high-quality image formation in a shortened lens configuration suitable for mobile devices
Solution Approach 2:
The patent optimizes the spacing between optical elements (d1/d2: 0.30-1.50, d3/d4: 0.20-0.80, d5/d6: 0.10-0.50) and the curvature radii relationships to achieve compact dimensions while maintaining aberration correction quality. The refractive power distribution and curvature parameter optimization enable the system to achieve both compact size and high image quality
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 configuration achieves a compact size with high resolution and proper aberration correction, reducing the telephoto ratio and maintaining low-profileness while facilitating mass production at lower costs.
Implementation Method 1
a first lens as a first optical element having positive refractive power
Implementation Method 2
a second lens as a second optical element having negative refractive power
Implementation Method 3
an aberration correction optical element as a fifth optical element having flat and aspheric surfaces facing both sides near the optical axis
Data Source
AI summary
An imaging lens comprises five optical elements, in order from an object side to an image side, comprising, a first lens as a first optical element having positive refractive power, a second lens as a second optical element having negative refractive power and a convex surface facing the object side near an optical axis, a third lens as a third optical element having the refractive power, and a fourth lens as a fourth optical element having refractive power and the convex surface facing the object surface near the optical axis, wherein and an aberration correction optical element as a fifth optical element are arranged between said third lens and said fourth lens, said aberration correction optical element has both flat surfaces near the optical axis and aspheric surfaces.