Four-Element Aspheric Lens Assembly for Compact Optical Systems
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Solution Overview
Problem
Conventional compact optical image lens assemblies for portable electronic products face challenges in achieving high image quality due to limitations in image quality, manufacturing complexity, and increased total optical track length, particularly with three-element and four-element lens structures.
Innovation Solution
An optical image lens assembly comprising a specific arrangement of four lens elements with aspheric surfaces, including a first lens with positive refractive power, a second with negative refractive power, a third with negative refractive power and aspheric surfaces, and a fourth with refractive power and inflection points, optimized to reduce total track length and enhance image quality through precise axial distances and focal length relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a three-element lens structure is used, then the lens assembly is compact, but the image quality is poor
Solution Approach 1:
The lens assembly is divided into four distinct lens elements instead of three, with each element having specific refractive power and surface characteristics. This segmentation allows for better correction of optical aberrations while maintaining a compact overall structure suitable for portable devices.
Solution Approach 2:
The patent employs aspheric surfaces on multiple lens elements (first, third, and fourth lens elements have aspheric object-side or image-side surfaces). This use of curved non-spherical surfaces enables more precise control over light paths, improving image quality by correcting spherical aberration and other optical defects while keeping the lens assembly compact.
2Manufacturing precision
If a four-element lens structure with glass spherical lenses is used, then chromatic aberration is eliminated, but the total optical track length increases and manufacturing becomes difficult
Solution Approach 1:
The patent changes the material parameter from glass to plastic for the lens elements, and changes the surface geometry parameter from spherical to aspheric. This allows for effective chromatic aberration correction and compact design using molded plastic lenses with aspheric surfaces, avoiding the need for complex glass lens attachment processes and reducing total optical track length.
Solution Approach 2:
Multiple lens elements feature aspheric surfaces instead of spherical surfaces. This enables more effective aberration correction with fewer elements and shorter optical track length, while the aspheric surfaces can be efficiently manufactured using plastic molding techniques rather than complex glass working and attachment processes.
3Manufacturing precision
If multiple spherical lenses are allocated, then chromatic aberration can be corrected, but the manufacturing process becomes difficult and complex
Solution Approach 1:
The patent changes the material from glass to plastic and the surface geometry from spherical to aspheric. This combination allows chromatic aberration correction to be achieved through single-molded plastic lens elements with aspheric surfaces, eliminating the need for complex multi-step glass lens attachment processes while maintaining manufacturing precision.
Solution Approach 2:
The use of molded plastic lens elements replaces expensive and complex glass lens assembly processes. The plastic lenses can be manufactured as complete aspheric elements in a single molding step, significantly simplifying the manufacturing process and reducing costs compared to attaching multiple glass spherical lenses.
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 total track length, improves image quality by correcting aberrations, and maintains the compact size of the lens assembly, making it suitable for lightweight and portable electronic products.
Implementation Method 1
The third lens element with negative refractive power has a convex object-side surface and a concave image-side surface. The object-side surface and the image-side surface of the third lens element are aspheric. The fourth lens element with refractive power has a concave image-side surface. The object-side surface and the image-side surface of the fourth lens element are aspheric.
Data Source
AI summary
An optical image lens assembly includes, in order from an object side to an image side, a first lens element with positive refractive power and having a convex object-side surface, a second lens element with negative refractive power, a third lens element with negative refractive power and having a convex object-side surface and a concave image-side surface, and a fourth lens element with refractive power and having a concave image-side surface.