Five-Element Plastic Lens System Aberration Correction
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Solution Overview
Problem
Conventional image capturing lens systems for portable electronic devices, such as smartphones and PDAs, face challenges in achieving high image quality and compactness due to their excessive total track length and inability to correct aberrations effectively.
Innovation Solution
An image capturing optical lens system comprising five lens elements with specific refractive powers and surface curvatures, including a first lens with positive refractive power, a second with negative refractive power, a third with negative refractive power, a fourth with positive refractive power, and a fifth with negative refractive power, all made of plastic, arranged to satisfy specific relations for curvature radii and focal lengths to reduce total track length and correct aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional five-lens element lens system is used to improve image quality, then image quality is improved, but total track length becomes excessively long
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive powers, focal lengths, and curvature radii of the five lens elements to satisfy specific mathematical relations. This allows the system to achieve high image quality with a compact total track length by precisely controlling optical parameters rather than simply reducing the number of elements.
Solution Approach 2:
The patent utilizes aspheric surfaces on multiple lens elements (third, fourth, and fifth lens elements have aspheric object-side or image-side surfaces) to correct aberrations more effectively. This curvature variation allows for better image quality while maintaining a compact structure compared to conventional spherical lens designs.
2Length of stationary object
If the number of lens elements is reduced to shorten total track length, then total track length is reduced, but aberration correction capability deteriorates
Solution Approach 1:
The patent employs aspheric surfaces on the third, fourth, and fifth lens elements to enhance aberration correction capability. These aspheric surfaces provide additional degrees of freedom for correcting spherical aberration, coma, and other off-axis aberrations, compensating for the limited number of lens elements while maintaining a compact total track length.
Solution Approach 2:
The patent optimizes specific parameter relations including the focal lengths of individual elements (f1, f2, f3, f4, f5), curvature radii (R1 through R10), and their ratios to achieve effective aberration correction. By precisely controlling these parameters, the system achieves good aberration correction with only five elements, avoiding the need for more elements that would increase total track length.
3Manufacturing precision
If cemented doublet lens elements are used to correct aberrations, then aberration correction is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent divides the optical system into five separate lens elements with air gaps between them, rather than using cemented doublet structures. This segmentation simplifies manufacturing and assembly by eliminating the need for precise cementing operations, while still achieving effective aberration correction through the optimized individual element designs and aspheric surfaces.
Solution Approach 2:
The patent uses aspheric surfaces on multiple lens elements to provide the necessary aberration correction without requiring cemented doublet structures. The aspheric profiles on the third, fourth, and fifth lens elements enable effective correction of spherical aberration and other aberrations through shape control alone, avoiding the complexity of cemented assemblies.
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 system achieves reduced total track length, improved image resolution, and effective correction of aberrations and astigmatism, making it suitable for high-image-quality, compact portable electronic devices.
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 negative refractive power
Implementation Method 2
a third lens element with negative refractive power having at least one of the object-side and image-side surfaces thereof being aspheric; a fourth lens element having at least one of the object-side and image-side surfaces thereof being aspheric
Data Source
AI summary
This invention provides an image capturing optical lens system 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 with negative refractive power; a third lens element with negative refractive power having at least one of the object-side and image-side surfaces thereof being aspheric; a fourth lens element having at least one of the object-side and image-side surfaces thereof being aspheric; a fifth lens element having a concave image-side surface, both the object-side and image-side surfaces thereof being aspheric, at least one inflection point is formed on at least one of the object-side surface and the image-side surface thereof, and the fifth lens element is made of plastic. By such arrangement, photosensitivity and total track length of the system can be reduced, and the aberration and astigmatism of the system can be effectively corrected. Moreover, high image resolution can be obtained.