Six-element lens assembly with aspheric inflection points
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Solution Overview
Problem
Conventional compact image capturing lens assemblies for portable electronic devices, such as smartphones, fail to meet the increasing demands for higher image quality and reduced total track length due to their four-element lens structure, which cannot effectively correct aberrations and maintain compact size.
Innovation Solution
An image capturing lens assembly comprising a sequence of lens elements with specific refractive powers and surface curvatures, including a first positive refractive power lens, a second negative refractive power lens, a third positive refractive power lens with convex surfaces, a fourth negative refractive power lens made of plastic with aspheric surfaces and inflection points, and a sixth negative refractive power lens with aspheric surfaces and inflection points, optimized to reduce total track length and correct aberrations.
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 deteriorates and total track length cannot be sufficiently reduced
Solution Approach 1:
The lens assembly is divided into six distinct lens elements with specific refractive powers and surface curvatures. Each element is optimized for specific aberration correction functions, allowing comprehensive correction of multiple aberration types simultaneously while maintaining a compact overall structure suitable for portable devices.
Solution Approach 2:
The patent employs aspheric surfaces on multiple lens elements, including the fourth and sixth lens elements which feature inflection points. These curved surfaces enable more effective correction of spherical aberration and other monochromatic aberrations compared to conventional spherical surfaces, improving image quality without increasing total track length.
2Manufacturing precision
If the number of lens elements is increased to improve image quality, then aberration correction is enhanced, but the total track length increases
Solution Approach 1:
The patent specifies precise parameter relationships between lens elements, including focal length ratios (0.25<f3/f1<0.45), curvature radius relationships ((R3-R4)/(R3+R4)=0.05-0.30), and axial distance constraints (0.05<T12/f<0.20). These parameter optimizations enable effective aberration correction with a compact total track length suitable for portable devices.
Solution Approach 2:
Each lens element is designed to perform multiple functions: the first positive element provides overall focusing power, the second negative element corrects spherical aberration, the third positive element with convex surfaces addresses coma and astigmatism, while the fourth and sixth elements with aspheric surfaces and inflection points provide comprehensive higher-order aberration correction. This multi-functionality reduces the need for additional elements.
3Manufacturing precision
If aspheric surfaces with inflection points are used, then aberration correction is improved, but manufacturing precision requirements increase
Solution Approach 1:
The fourth and sixth lens elements incorporate aspheric surfaces with inflection points strategically positioned to correct higher-order spherical aberration and other complex aberrations. The aspheric profiles are defined with specific mathematical parameters that enable effective aberration control while being manufacturable using precision molding techniques for plastic lenses or precision grinding for glass lenses.
Solution Approach 2:
The patent allows different material compositions for different lens elements, including plastic and glass materials with specific refractive indices and Abbe numbers. This material selection flexibility enables optimization of both optical performance and manufacturability, as plastic aspheric lenses can be cost-effectively produced via injection molding while glass elements offer superior precision for critical aberration correction.
4Length of stationary object
If the total track length is reduced for compact devices, then portability is improved, but aberration correction capability deteriorates
Solution Approach 1:
The patent establishes specific parameter constraints that enable compact design: the ratio of axial distance between first and second elements to focal length (0.05<T12/f<0.20), the focal length ratio of third to first element (0.25<f3/f1<0.45), and curvature radius relationships ((R3-R4)/(R3+R4)=0.05-0.30). These parameter optimizations allow effective aberration correction within a reduced total track length suitable for smartphones and portable devices.
Solution Approach 2:
The patent utilizes the radial dimension through aspheric surfaces and inflection points to achieve aberration correction that would otherwise require additional axial length. The aspheric profiles vary the surface curvature in the radial direction, enabling compact correction of spherical and coma aberrations without increasing the total track length along the optical axis.
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 achieves improved image quality, reduced total track length, and compact size by effectively correcting aberrations and maintaining high image quality while allowing for digital zoom and image cropping, suitable for lightweight and portable electronic devices.
Implementation Method 1
a first lens element (110), a second lens element (120), a third lens element (130), a fourth lens element (140), a fifth lens element (150) and a sixth lens element (160)... The first lens element is with positive refractive power. The second lens element is with refractive power.
Implementation Method 2
The fourth lens element with refractive power is made of plastic material, wherein at least one surface of the fourth lens element is aspheric... the sixth lens element has at least one inflection point formed on at least one of the object-side surface and the image-side surface thereof.
Data Source
AI summary
An image capturing lens assembly includes, in order from an object side to an image side: the first lens element with positive refractive power, the second lens element with refractive power, the third lens element with positive refractive power, the fourth lens element with refractive power, the fifth lens element with refractive power, and the sixth lens element with refractive power, at least one surface of the sixth lens element thereof being aspheric and having at least one inflection point. By such arrangement, total track length and the photosensitivity of the image capturing lens assembly can also be effectively reduced while retaining high image quality.