Five-Element Lens Assembly Aberration Correction
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Solution Overview
Problem
Conventional compact optical lens systems, such as those with four-element or five-element structures, fail to meet the increasing demands for high resolution and image quality in portable electronic products due to issues like excessive spherical aberration, unbalanced refractive power distribution, and difficulty in reducing back focal length.
Innovation Solution
An image capturing lens assembly comprising five lens elements with specific refractive powers and surface curvatures, including a first lens with positive refractive power, a second lens with negative refractive power, a third lens with positive refractive power, a fourth lens with negative refractive power, and a fifth lens with negative refractive power, where the focal lengths and axial distances between the elements are optimized to reduce spherical aberration and maintain a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional four-element lens structure is used, then the device complexity is reduced, but the image quality and resolution cannot satisfy high-end requirements
Solution Approach 1:
The patent divides the optical system into five distinct lens elements with specific refractive power distributions (positive, negative, positive, negative, negative). This segmentation allows each element to contribute differently to aberration correction, enabling high image quality while maintaining reasonable structural complexity. The fifth element with negative refractive power is particularly added to address spherical aberration that cannot be corrected with conventional four-element designs.
2Device complexity
If the third lens element does not have positive refractive power, then the device complexity is reduced, but spherical aberration becomes excessive due to unbalanced refractive power distribution
Solution Approach 1:
The patent specifies precise refractive power parameters for each lens element, particularly requiring the third element to have positive refractive power and the fifth element to have negative refractive power. These parameter changes create a balanced distribution of optical power that effectively corrects spherical aberration. The specific focal length ratios (e.g., f3/f1, f5/f4) are optimized to achieve the desired aberration correction while maintaining compact dimensions.
3Device complexity
If the fourth and fifth lens elements do not both have negative refractive power, then the device complexity is reduced, but the back focal length cannot be reduced efficiently
Solution Approach 1:
The patent applies local quality by assigning negative refractive power specifically to the fourth and fifth lens elements, creating a localized region of negative optical power near the image plane. This local configuration of negative power elements effectively shortens the back focal length, allowing the lens assembly to be more compact while maintaining proper focus. The specific surface curvatures (concave-convex for fourth element, convex-concave for fifth element) are optimized to achieve this compact back focal length.
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 solution effectively corrects aberrations, reduces the total track length, and maintains a compact size, enhancing image quality and resolution while allowing for efficient manufacturing and application in portable electronic devices.
Implementation Method 1
The first lens element with positive refractive power, the second lens element with refractive power, the third lens element with positive refractive power, the fourth lens element with negative refractive power, and the fifth lens element with negative refractive power
Data Source
AI summary
An image capturing lens assembly includes, in order from an object side to an image side, 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 an object-side surface being convex at a paraxial region thereof. The second lens element with refractive power has an object-side surface being convex at a paraxial region thereof. The third lens element has positive refractive power. The fourth lens element with negative refractive power has an object-side surface being concave at a paraxial region thereof and an image-side surface being convex at a paraxial region thereof. The fifth lens element with negative refractive power has an image-side surface being concave at a paraxial region thereof and being convex at a peripheral region thereof, wherein the surfaces of the fifth lens element are aspheric.