Four-Element Aspheric Lens Assembly for Compact Mobile Imaging
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Solution Overview
Problem
Conventional image-capturing lens assemblies for mobile phone cameras are inadequate due to increased demand for compact, high-resolution lenses with better image quality, as they often require complex manufacturing processes and cannot easily reduce total track length.
Innovation Solution
A compact image-capturing lens assembly comprising four lens elements with specific refractive powers and surface configurations, including a first lens element with positive refractive power, a second with negative refractive power, a third with positive refractive power and a concave object-side surface, and a fourth with negative refractive power and an inflection point, along with a stop placement that reduces total track length and corrects aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional triplet lens assembly is used, then the structure is simple, but the image quality is insufficient for high-resolution sensors
Solution Approach 1:
The lens assembly is divided into four distinct lens elements with specific refractive powers and surface configurations. Each element is optimized for particular aberration correction functions, allowing high-resolution imaging performance that exceeds conventional triplet designs while maintaining a manageable structural complexity
Solution Approach 2:
Different surfaces of the lens elements are assigned different aspheric coefficients and refractive powers tailored to their specific optical functions. For example, the third lens element has a concave object-side surface with specific aspheric characteristics optimized for correcting certain aberrations, while the fourth element has an inflection point on its image-side surface for correcting other aberrations, achieving superior local optical quality
2Manufacturing precision
If spherical glass lenses are used with chromatic aberration correction, then the chromatic aberration is corrected, but the total track length cannot be reduced easily
Solution Approach 1:
The patent employs aspheric surfaces with specifically optimized aspheric coefficients for each lens element. This parameter change from spherical to aspheric surfaces allows for more flexible aberration correction and enables compact total track length while maintaining excellent chromatic aberration correction performance through optimized refractive index selections and surface curvatures
Solution Approach 2:
The lens assembly uses multiple lens elements with different refractive indices and Abbe numbers, creating a composite optical system. This composite structure enables effective chromatic aberration correction through the combined dispersive properties of different materials while maintaining a compact overall length
3Manufacturing precision
If the number of lens elements is increased to improve image quality, then the image quality improves, but the manufacturing process becomes complicated
Solution Approach 1:
The optical system is segmented into four lens elements, each with specific refractive powers and aspheric surface configurations. This segmentation allows for optimized correction of various aberrations (spherical, coma, astigmatism, field curvature) while keeping each individual element relatively simple to manufacture with standard aspheric molding techniques
Solution Approach 2:
The patent utilizes aspheric surfaces on multiple lens elements with specifically optimized aspheric coefficients. These controlled curvature variations enable effective aberration correction while being compatible with modern injection molding and glass molding processes, making the manufacturing feasible despite the increased number of elements
4Length of moving object
If a compact lens assembly is designed, then the size is reduced, but the sensitivity of the optical system increases
Solution Approach 1:
The patent achieves compact total track length through optimized parameter selection including aspheric coefficients, refractive indices, and surface curvatures. The specific aspheric profiles and refractive power distributions are designed to maintain stable optical performance and reduced sensitivity to manufacturing tolerances and environmental variations, despite the compact form factor
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 reduces the size and sensitivity of the lens assembly, improves resolution, and simplifies the manufacturing process while maintaining a compact form, enabling better image quality and reduced aberrations.
Implementation Method 1
a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element with positive refractive power having a concave object-side surface and a convex image-side surface
Data Source
AI summary
This invention provides an image-capturing lens assembly comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element with positive refractive power having a concave object-side surface and a convex image-side surface, the object-side and image-side surfaces thereof being aspheric; a fourth lens element with negative refractive power having a concave image-side surface on which at least one inflection point is formed, the object-side and image-side surfaces thereof being aspheric; and a stop disposed between an imaged object and the first lens element; wherein there are four lens elements with refractive power. Such an arrangement of optical elements can effectively reduce the size of the lens assembly, mitigate the sensitivity of the optical system and enable the lens assembly to obtain a higher resolution.