Six-Element Plastic Lens Assembly for Compact Imaging
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Solution Overview
Problem
Conventional compact imaging lens systems with five lens elements fail to meet the increasing demands for higher pixel size and image quality in advanced portable electronic devices, particularly in smartphones and PDAs, while also requiring a more compact and high-performance design.
Innovation Solution
The proposed image capturing lens assembly consists of six lens elements, including a first lens with positive refractive power, a second with negative refractive power, a third, a fourth with aspheric surfaces, a fifth with positive refractive power and an inflection point, and a sixth with negative refractive power and aspheric surfaces, optimized to reduce total track length and correct aberrations, using plastic materials to enhance design flexibility and reduce production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If five lens elements are used in a compact imaging lens system, then the device can be made more compact, but the image quality and pixel size requirements cannot be met
Solution Approach 1:
The imaging lens system is divided into six distinct lens elements with specific refractive power assignments (positive, negative, positive, positive, negative, negative). This segmentation allows each element to contribute differently to the overall optical performance, enabling better image quality correction while maintaining a compact total track length that exceeds the conventional five-element design only by a minimal margin.
Solution Approach 2:
Different lens elements are assigned specific local optical properties: the first lens element has positive refractive power with a convex object-side surface, the second has negative refractive power, the fourth has aspheric surfaces, the fifth has positive refractive power with a convex image-side surface, and the sixth has negative refractive power with a concave image-side surface. This local differentiation of optical properties enables precise correction of aberrations and achievement of high image quality while keeping the overall system compact.
2Manufacturing precision
If more lens elements are added to improve image quality, then image resolution improves, but the total track length increases
Solution Approach 1:
The patent specifies precise parameter relationships to control the total track length: |R10/R11| < 0.5, where R10 is the radius of curvature of the image-side surface of the fifth lens element and R11 is the radius of curvature of the object-side surface of the six lens element. Additionally, the focal length relationship (|f5|+|f6|)/(|f3|+|f4|) < 0.5 is enforced. These parameter constraints ensure that while six lens elements are used for high image quality, the total track length remains compact and suitable for portable devices.
3Manufacturing precision
If aspheric surfaces are used on multiple lens elements, then aberration correction improves, but manufacturing complexity increases
Solution Approach 1:
Aspheric surfaces are applied selectively to only four out of six lens elements (the second, fourth, fifth, and sixth elements), rather than all elements. This partial application provides sufficient aberration correction to achieve high image quality while avoiding the excessive manufacturing complexity that would result from making all six elements aspheric. The aspheric surfaces on these specific elements effectively correct spherical aberration, coma, and other off-axis aberrations.
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
This configuration achieves improved image resolution, reduced aberrations, and a compact form factor suitable for high-performance portable devices by effectively managing refractive power and surface curvature, while maintaining a moderate total track length and enhancing photosensitivity.
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; a fourth lens element having at least one of an object-side surface and an image-side surface thereof being aspheric; a fifth lens element with positive refractive power having a convex image-side surface, and at least one of an object-side surface and the image-side surface thereof being aspheric; and a sixth lens element with negative refractive power having a concave image-side surface, and at least one inflection point is formed on at least one of an object-side surface and the image-side surface thereof
Data Source
AI summary
This invention provides an image capturing lens assembly, in order from an object side to an image side comprising: a first lens element with positive refractive power having a convex object-side surface; a second lens element; a third lens element; a fourth lens element having at least one of an object-side surface and an image-side surface thereof being aspheric; a fifth lens element with positive refractive power having a convex image-side surface, at least one of an object-side surface and the image-side surface thereof being aspheric, and the fifth lens element is made of plastic; and a sixth lens element with negative refractive power having a concave image-side surface, at least one of an object-side surface and the image-side surface thereof being aspheric, and the sixth lens element is made of plastic. By such arrangement, the photo-sensitivity and the total track length of the image capturing lens assembly can be reduced. Furthermore, the aberration and astigmatism of the assembly can be effectively corrected for obtaining higher image resolution.