Five-Lens Optical Assembly with Aspheric Surfaces for Compact Imaging
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Solution Overview
Problem
Conventional optical lens assemblies for compact electronic devices, such as web cameras and mobile phones, face challenges in achieving a compact design with good aberration correction and high resolution while maintaining cost-effectiveness for mass production, as they often require complex lens combinations that increase manufacturing costs and total length.
Innovation Solution
A five-lens optical lens assembly with specific refractive power combinations and surface shapes, including aspheric surfaces and inflection points, is designed to reduce the total length and manufacturing costs, featuring a first lens with positive refractive power, a second lens with negative power, a third lens made of plastic with aspheric surfaces, a fourth lens with positive power and concave surfaces, and a fifth lens with negative power and aspheric surfaces, optimized by relations such as TD, SD/TD, and focal length ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a five-lens design is used to improve image quality and aberration correction, then the manufacturing cost and total length increase
Solution Approach 1:
The patent employs aspheric surfaces on multiple lens elements (first, third, fourth, and fifth lens elements) to correct spherical aberration and other optical imperfections. The aspheric surfaces allow for better aberration correction with fewer lens elements compared to traditional spherical surfaces, thereby reducing the total length while maintaining high image quality
Solution Approach 2:
The patent optimizes specific parameter relationships including the ratio of focal lengths (0.3 < |f5/f4| < 0.7), the ratio of axial distances (0.1 < SD/TD < 0.5), and the curvature radii relationships to achieve compact design. By carefully controlling these parameters, the system achieves excellent aberration correction and telecentricity with a reduced total length of 1.0 < TTL/f < 2.0
2Manufacturing precision
If the fourth lens element has a convex object-side surface and concave image-side surface to compensate aberration, then the surface shapes must be precisely matched which is unfavorable for mass production
Solution Approach 1:
The patent uses aspheric surfaces with standardized profiles on the fourth and fifth lens elements. The aspheric coefficients are optimized to work together as a pair, where the fourth lens element has a convex object-side surface and concave image-side surface, and the fifth lens element has a convex object-side surface and concave image-side surface. This standardized aspheric design allows for precise aberration compensation while maintaining ease of mass production through consistent manufacturing processes
3Adaptability or versatility
If a first lens element with convex object-side surface is used to decrease refractive angle, then the view angle increases but aberration correction becomes more difficult
Solution Approach 1:
The first lens element features an aspheric object-side surface with a convex shape that decreases the refractive angle of incident light, enabling a wider view angle (2ω ≥ 60°). The aspheric profile is specifically designed to maintain excellent aberration correction across the wide field of view, resolving the trade-off between view angle and aberration control
Solution Approach 2:
The patent optimizes the curvature radius relationships and aspheric coefficients of the first lens element to achieve the desired balance. The object-side surface curvature is designed to broaden the view angle while the aspheric terms are optimized to correct the introduced aberrations, achieving both wide angle (2ω ≥ 60°) 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
This design achieves good aberration correction, improved modulation transfer function, and a compact form factor while reducing production costs, allowing for a shorter optical system with enhanced image quality and a larger effective pixel range within the same total length.
Implementation Method 1
a first lens element, the second lens element, the third lens element, a fourth lens element and a fifth lens element... the first lens element with positive refractive power... the second lens element with negative refractive power
Data Source
AI summary
An optical lens assembly for imaging pickup, sequentially arranged from an object side to an image side, comprising: a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element. The first lens element with positive refractive power has a convex object-side surface. The second lens element has negative refractive power. The third lens element with refractive power has bi-aspheric surfaces. The fourth lens element with positive refractive power has a concave object-side surface and a convex image-side surface and both being aspheric. The fifth lens element with negative refractive power has a concave image-side surface, bi-aspheric surfaces and at least one inflection point. Therefore, the optical lens assembly for imaging pickup satisfies conditions related to shorten the total length and to reduce the sensitivity for use in compact cameras and mobile phones with camera functionalities.