Five-Element Imaging Lens Compact System Length
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Solution Overview
Problem
Conventional imaging lenses with four or five elements fail to meet the requirements of miniaturization while maintaining high image quality and a large field of view, as they either have a limited half field-of-view or an excessively long system length.
Innovation Solution
A five-element imaging lens configuration with specific surface profiles and materials, including a first lens element with negative refractive power, a second and third lens element with positive refractive power, a fourth lens element with positive refractive power, and a fifth lens element made of plastic, arranged to optimize optical performance and reduce system length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of lens elements is increased to improve image quality and field of view, then optical performance is improved, but system length increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive powers, curvature radii, and thicknesses of each lens element. Specific parameters such as the ratio of focal length to effective diameter, and the curvature radii of object-side and image-side surfaces are optimized to achieve compact dimensions while maintaining optical performance. The fifth lens element's specific refractive power range and surface curvature parameters are critical in reducing system length without sacrificing image quality
Solution Approach 2:
The patent employs composite material strategy by combining different lens materials with specific refractive indices and Abbe numbers. The first through fourth lens elements use materials with different optical properties to correct chromatic and spherical aberrations, while the fifth lens element uses plastic material. This composite approach allows achieving high optical performance with a compact five-element configuration
2Length of moving object
If the system length is reduced to achieve miniaturization, then device dimensions are reduced, but optical performance deteriorates
Solution Approach 1:
The patent applies local quality by giving each lens element specific local characteristics tailored to its position in the optical system. The first lens element has negative refractive power with specific surface curvatures to control light convergence, while subsequent elements have positive refractive power with varying surface profiles. The aperture stop is positioned between the second and third lens elements to locally control light paths and reduce aberrations in compact configuration
Solution Approach 2:
The patent extensively uses curved surfaces with specific curvature radii to optimize light paths in the compact system. Each lens element has object-side and image-side surfaces with precisely defined curvature radii that are critical for correcting spherical and chromatic aberrations. The convex portions on object-side surfaces and corresponding concave portions on image-side surfaces create optimized light convergence patterns that maintain high optical performance despite reduced system length
3Adaptability or versatility
If conventional five-element lens designs are used to achieve large field of view, then HFOV is improved, but system length becomes excessively long
Solution Approach 1:
The patent applies dynamics by creating a flexible optical system where the aperture stop can be positioned between the second and third lens elements to dynamically control light paths. This dynamic positioning allows the system to achieve large half field-of-view (greater than 40 degrees) while maintaining compact dimensions through optimized light convergence angles and reduced optical path lengths
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 reduced system length while maintaining good optical performance, including low spherical and chromatic aberrations, and distortion, enabling the development of thinner, cost-effective portable electronic devices with improved imaging capabilities.
Implementation Method 1
The first lens element has a negative refractive power
Implementation Method 2
The object-side surface of the second lens element has a convex portion in a vicinity of the optical axis. The image-side surface of the third lens element has a convex portion in a vicinity of the optical axis. The image-side surface of the fourth lens element has a convex portion in a vicinity of the optical axis.
Data Source
AI summary
An imaging lens includes a first lens element, a second lens element, an aperture stop, a third lens element, a fourth lens element, and a fifth lens elements arranged from an object side to an image side in the given order. Through designs of surfaces of the lens elements and relevant optical parameters, a short system length of the imaging lens may be achieved while maintaining good optical performance.