Five-Element Aspheric Lens Assembly for Compact Mobile Imaging
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Solution Overview
Problem
Conventional compact photographing lens assemblies for portable electronic devices fail to meet the increasing demands for higher image quality and reduced total track length, which are essential for modern high-performance and compact mobile electronics.
Innovation Solution
A photographing optical lens assembly comprising five elements with specific refractive powers and aspheric surfaces, including a first lens with positive refractive power, a second lens with negative refractive power and aspheric surfaces, a third lens with a concave image-side surface, a fourth lens with positive refractive power and aspheric surfaces, and a fifth lens with negative refractive power and inflection points, optimized to correct aberrations and reduce the total track length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional four-element lens structure is used, then the device complexity is reduced, but the image quality and imaging performance cannot satisfy high-pixel requirements
Solution Approach 1:
The patent divides the lens assembly into five distinct lens elements with specific refractive power distributions (first element: positive, second element: negative, third element: positive, fourth element: negative, fifth element: positive). This segmentation allows each element to be optimized for specific aberration corrections, achieving superior image quality that cannot be obtained with a conventional four-element structure.
Solution Approach 2:
The patent applies aspheric surfaces to specific lens elements (first, second, and fourth elements have aspheric object-side surfaces) rather than uniformly across all surfaces. This local application of aspheric design targets specific aberration problems in critical regions of the optical path, improving image quality where it matters most while controlling manufacturing complexity.
2Length of moving object
If the total track length is reduced for compact size, then the portability is improved, but the aberration correction capability deteriorates
Solution Approach 1:
The patent employs a dynamic combination of positive and negative refractive powers across five lens elements, with specific focal length ratios (f3/f1 between 0.3-0.7, f4/f1 between -0.5 and -0.8). This dynamic refractive power distribution allows the compact lens assembly to maintain adequate aberration correction capability despite the reduced total track length.
Solution Approach 2:
The patent optimizes specific parameter relationships including the focal length ratios (f3/f1, f4/f1, f5/f1), curvature radius ratios (R1/R2, R3/R4), and thickness ratios (d1/f1, d2/f1). These parameter changes enable the compact design to achieve proper aberration correction by carefully balancing optical parameters within the constrained total track length.
3Manufacturing precision
If aspheric surfaces are added to correct aberrations, then the image quality is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies aspheric surfaces selectively to only three lens elements (first, second, and fourth elements) rather than all five elements. This local application provides sufficient aberration correction while reducing the total number of aspheric surfaces that require complex manufacturing, thereby balancing image quality improvement with manufacturing feasibility.
Solution Approach 2:
The patent controls the aspheric surface parameters within specific ranges (conic constants k1, k2, k4 between -6 to -10; higher-order coefficients A4-A16 within defined ranges). By constraining these parameters to practical ranges, the patent achieves effective aberration correction while keeping the manufacturing precision requirements within achievable limits for modern lens fabrication processes.
4Length of moving object
If the focal length is shortened for compact design, then the total track length is reduced, but the light gathering capability decreases
Solution Approach 1:
The patent uses five lens elements with alternating positive and negative refractive powers to create a telecentric optical design. This segmentation allows the system to achieve a short total track length while maintaining adequate light gathering capability through the coordinated action of multiple elements that preserve chief ray angles and improve illumination uniformity across the image plane.
Solution Approach 2:
The patent optimizes the focal length ratios (f3/f1 between 0.3-0.7, f4/f1 between -0.5 and -0.8, f5/f1 between 0.2 and 0.5) and aperture considerations to maintain adequate light gathering capability despite the shortened focal length. The specific parameter relationships ensure that the compact design does not excessively compromise the f-number and light transmission.
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 lens assembly achieves improved image quality and a reduced total track length, maintaining compact size and performance suitable for lightweight portable electronic devices by effectively correcting aberrations and enhancing focal length relationships.
Implementation Method 1
a first lens element (110), a second lens element (120), a third lens element (130), a fourth lens element (140) and a fifth lens element (150)... The first lens element with positive refractive power, the second lens element with negative refractive power
Data Source
AI summary
A photographing optical lens assembly includes, in order from an object side to an image side: a first lens element with positive refractive power, a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface, a third lens element having a concave image-side surface, wherein at least one of the object-side surface and the image-side surface of the third lens element is aspheric, a fourth lens element with positive refractive power having a convex image-side surface, wherein at least one of the object-side surface and the image-side surface of the fourth lens element is aspheric, and a fifth lens element with negative refractive power having a concave image-side surface, wherein at least one of the object-side surface and the image-side surface of the fifth lens element is aspheric.