Three-Element Aspheric Lens Assembly for Infrared Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional compact optical lens systems for electronic products face limitations in aberration correction, field of view, and manufacturing complexity, which affects image quality and suitability for infrared photography under low light conditions.
Innovation Solution
A photographing lens assembly comprising three lens elements with specific refractive powers and surface curvatures, including a first lens with positive refractive power, a second lens with positive refractive power, and a third lens with negative refractive power made of plastic, optimized for compact size, reduced aberration, and increased field of view, with aspheric surfaces and carefully controlled curvature radii and focal lengths to achieve high image quality and infrared capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a two-lens element structure is adopted to cut down manufacturing cost, then manufacturing cost is reduced, but aberration correction ability is limited and imaging quality does not satisfy higher imaging demands
Solution Approach 1:
The patent applies local quality by assigning different refractive powers and surface curvature characteristics to each lens element. The first lens element has positive refractive power with specific concave/convex surface configuration, the second lens element has negative refractive power, and the third lens element has positive refractive power. This localized optimization of optical properties at different positions enables effective aberration correction while maintaining a compact three-element structure that balances manufacturing feasibility with imaging quality requirements.
2Manufacturing precision
If a four-element lens structure is used to improve aberration correction, then aberration correction ability is improved, but compact size is limited and manufacturing cost rises
Solution Approach 1:
The patent employs parameter changes by precisely controlling the refractive powers and surface curvature radii of each lens element. The first lens element has object-side surface curvature radius R1 and image-side surface curvature radius R2 satisfying specific relationships with f-number Fno. The third lens element has aspheric surfaces with specific curvature radius relationships. These optimized parameters enable a three-element structure to achieve aberration correction performance comparable to four-element designs while maintaining compact size and reducing manufacturing complexity.
3Area of stationary object
If a three-element lens structure with positive-positive-positive refractive powers is used to increase field of view, then field of view is increased, but back focal length is increased and total track length becomes too long
Solution Approach 1:
The patent applies asymmetry by using an asymmetric three-element configuration with positive-negative-positive refractive powers instead of symmetric positive-positive-positive. The first lens element has positive refractive power with concave object-side and convex image-side surfaces, the second lens element has negative refractive power, and the third lens element has positive refractive power with aspheric surfaces. This asymmetric arrangement allows the system to achieve wide field of view while maintaining short back focal length and compact total track length suitable for electronic products.
4Ease of manufacture
If conventional optical lens systems are used, then manufacturing is simpler, but they cannot detect infrared rays at night under insufficient light source or capture dynamic images
Solution Approach 1:
The patent applies composite materials by selecting lens elements with specific material properties suitable for infrared photography. The lens elements are made from materials with appropriate refractive indices and transmission characteristics for infrared wavelengths. The combination of three lens elements with different refractive powers and the aspheric surfaces creates an optical system that maintains manufacturability while enabling infrared detection capability for night photography and dynamic imaging under low light conditions.
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 provides improved image quality, increased field of view, reduced aberration, and compact size, enabling effective infrared photography even under low light conditions, while also reducing manufacturing costs and complexity.
Implementation Method 1
a first lens element with positive 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
Data Source
AI summary
A photographing lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element and a third lens element. The first lens element with positive 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 second lens element has positive refractive power. The third lens element with negative refractive power made of plastic material, and has an image-side surface being concave at a paraxial region thereof and being convex at a peripheral region thereof, wherein an object-side surface and the image-side surface of the third lens element are aspheric.