Five-Lens Optical System with Aspheric Surfaces
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Solution Overview
Problem
Conventional compact optical lens systems, such as those with four-element and five-element lens structures, fail to meet the increasing demands for higher image quality and reduced size in portable electronic devices like smartphones and PDAs, due to limitations in refractive power distribution and aberration correction.
Innovation Solution
An optical image system comprising a specific arrangement of lens elements with aspheric surfaces and refractive powers, including a first lens with positive refractive power, a second with negative power, a third with aspheric surfaces, a fourth with balanced refractive power for spherical aberration correction, and a fifth with inflection points for reduced total track length and aberration correction, along with a flat element to enhance compactness and image quality.
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 refractive power distribution cannot satisfy high-end requirements
Solution Approach 1:
The lens system is divided into five distinct lens elements, each with specific refractive power assignments. The first lens has positive refractive power for converging light, the second has negative refractive power for divergence control, and the third through fifth lenses have balanced refractive powers for aberration correction. This segmentation allows optimized optical performance while maintaining manageable complexity.
Solution Approach 2:
Each lens element is designed with specific local characteristics - aspheric surfaces on the third and fourth lenses for aberration correction, inflection points on the fifth lens for compactness, and specific curvature radii optimized for their individual functions. This local optimization of quality attributes resolves the contradiction between simplicity and image quality.
2Manufacturing precision
If a conventional five-element lens structure with flat element is used, then the image quality is improved, but the total track length cannot be significantly reduced
Solution Approach 1:
The patent employs aspheric surfaces on the third and fourth lens elements instead of conventional spherical or flat surfaces. These aspheric surfaces provide better aberration correction and enable more compact optical paths. The fifth lens element includes inflection points that further reduce the total track length while maintaining image quality, directly addressing the contradiction between length and optical performance.
Solution Approach 2:
The patent optimizes specific parameters including curvature radii (R10 for the fifth lens), inflection point positions, and axial distances (Td between first and fifth lenses). By carefully controlling these parameters within specific ranges, the system achieves compact total track length while maintaining high image quality through precise optical parameter management.
3Measurement precision
If the pixel size of sensors is reduced to achieve higher megapixels, then the resolution is improved, but the optical lens system becomes more difficult to miniaturize
Solution Approach 1:
The five-lens structure is arranged in a compact nested configuration where each lens element is positioned to optimize space utilization. The aspheric surfaces and inflection points enable tighter spacing between elements, creating a miniaturized optical system that fits within small sensor packages while maintaining high resolution capability.
Solution Approach 2:
The lens elements can be manufactured from composite materials or single-piece molded optics with aspheric surfaces. This allows integration of multiple optical functions into single elements or compact assemblies, reducing the overall size of the optical system while maintaining the performance required for high-megapixel sensors.
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 described optical image system achieves improved image quality, reduced size, and corrected aberrations by optimizing the refractive powers and surface curvatures of the lens elements, while allowing for flexible material choices like glass or plastic, thereby addressing the limitations of conventional systems.
Implementation Method 1
a first lens element with positive refractive power, a second lens element with negative refractive power, a third lens element with refractive power, a fourth lens element with refractive power, and a fifth lens element with refractive power
Data Source
AI summary
An optical image system 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 a convex object-side surface. The second lens element has negative refractive power. The third lens element has refractive power, wherein two surfaces of the third lens element are aspheric. The fourth lens element with refractive power has a convex image-side surface, wherein two surfaces of the fourth lens element are aspheric. The fifth lens element with refractive power has a concave image-side surface, wherein two surfaces of the fifth lens element are aspheric, and the fifth lens element has an inflection point on the image-side surface thereof.