Six-Element Aspheric Lens Assembly for Compact Image Capture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical systems are large in size due to spherical lens surfaces, making them unsuitable for compact portable devices and unable to meet current technology trends for miniaturized, high-quality image capture.
Innovation Solution
A photographing optical lens assembly comprising six lens elements with specific refractive powers and surface curvatures, including a second lens element with positive refractive power, a third lens element with negative refractive power, and a sixth lens element with a concave image-side surface having an inflection point, optimized to reduce size and improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spherical lens surfaces are used in conventional optical systems, then the optical system can be manufactured with standard spherical lenses, but the size of the optical system becomes large and unsuitable for compact portable devices
Solution Approach 1:
The patent applies aspheric surfaces to lens elements instead of traditional spherical surfaces. Specifically, the first lens element has an aspheric object-side surface, the fourth lens element has an aspheric image-side surface, and the sixth lens element has an aspheric image-side surface. This curvature modification allows for compact optical system design while maintaining manufacturing feasibility through standard aspheric lens fabrication processes.
2Volume of moving object
If the optical system is reduced in size for compact devices, then portability is improved, but image quality deteriorates due to increased aberrations
Solution Approach 1:
Aspheric surfaces on multiple lens elements (first, fourth, and sixth elements) correct optical aberrations more effectively than spherical surfaces, enabling compact design without sacrificing image quality. The aspheric profiles allow precise control of light rays throughout the compact optical path.
Solution Approach 2:
The patent employs specific refractive index parameters and Abbe numbers for each lens element to optimize performance. The sixth lens element has an Abbe number between 20 and 50, and specific focal length ratios are maintained (e.g., f/f6 between -0.60 and -0.20) to balance compactness and image quality.
3Device complexity
If conventional spherical lens elements are used, then the optical design is simpler, but the back focal length becomes too long for compact device integration
Solution Approach 1:
The aspheric surfaces on the first, fourth, and sixth lens elements enable shorter back focal length by more efficiently controlling light convergence. The sixth lens element's aspheric image-side surface specifically helps reduce the distance from the last lens element to the image plane.
Solution Approach 2:
The patent specifies particular parameter ranges to achieve compact back focal length: the sixth lens element has negative refractive power with focal length ratio f/f6 between -0.60 and -0.20, and the curvature radius ratios are controlled (R1/R6 between -0.50 and 0.50, R7/R12 between -0.50 and 0.50) to optimize the optical path length.
4Manufacturing precision
If more lens elements are added to correct aberrations, then image quality improves, but the optical system size and complexity increase
Solution Approach 1:
Each lens element in the six-element system performs multiple functions: the first element provides initial light convergence with aspheric correction, the second and third elements contribute to focal length and aberration control, the fourth element provides additional aspheric correction, the fifth element fine-tunes the optical path, and the sixth element with its aspheric surface and inflection point provides final aberration correction and compact back focal length. This multi-functional design achieves high image quality without excessive size increase.
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 optical lens assembly achieves a compact design while maintaining high image quality by correcting aberrations and reducing the back focal length, enabling its use in compact devices.
Implementation Method 1
The second lens element has positive refractive power. The third lens element has negative refractive power. The sixth lens element with negative refractive power has an image-side surface being concave in a paraxial region thereof
Data Source
AI summary
A photographing optical lens assembly includes six lens elements which are, 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, a fifth lens element and a sixth lens element. The second lens element has positive refractive power. The third lens element has negative refractive power. The sixth lens element with negative refractive power has an image-side surface being concave in a paraxial region thereof, wherein the image-side surface of the sixth lens element has at least one inflection point.