Aspheric Plastic Lens Assembly for Compact Mobile Camera
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional high-resolution camera lenses are difficult to manufacture due to the complexity of bonding glass lens elements and are heavy and costly, making them unsuitable for miniaturization and integration into mobile electronic devices.
Innovation Solution
An optical imaging lens assembly comprising a sequence of lens elements with specific refractive powers and aspheric surfaces, including a first positive lens element, a second negative lens element, a third positive lens element with a convex image-side surface, and a fourth negative lens element with a concave image-side surface, optimized to correct aberrations and reduce the overall size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional glass spherical lens elements are bonded to form a doublet lens element for correcting chromatic aberration, then chromatic aberration correction is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the chromatic aberration correction function from the complex glass doublet bonding process and implements it through a simpler alternative: using a plastic lens element with specific dispersion properties (Abbe number between 20 and 50) combined with aspheric surface design. This eliminates the need for precision glass bonding while maintaining optical performance.
Solution Approach 2:
The patent changes the material parameter from glass to plastic with specific refractive index (1.5-1.7) and Abbe number (20-50) ranges, and combines this with aspheric surface parameters (higher-order coefficients) to achieve chromatic aberration correction without complex manufacturing processes.
2Reliability
If conventional high resolution camera lens uses glass spherical lens elements, then image quality is improved, but weight and manufacturing cost increase
Solution Approach 1:
The patent replaces expensive, heavy glass lens elements with more affordable plastic lens elements that can be molded directly. While plastic may have different durability characteristics, it achieves the required optical performance for mobile devices at reduced weight and cost, with aspheric surfaces providing enhanced image quality.
Solution Approach 2:
The patent uses composite optical design combining plastic material properties (refractive index 1.5-1.7, Abbe number 20-50) with aspheric surface geometry (defined by conic constant and higher-order coefficients) to create a lens system that achieves glass-level image quality with plastic material benefits of reduced weight and cost.
3Reliability
If conventional high resolution camera lens uses glass spherical lens elements, then image quality is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces the mechanical precision bonding process required for glass doublet lenses with a direct plastic molding process that integrates chromatic aberration correction into the single lens element design through aspheric surfaces and material selection, eliminating complex assembly steps and reducing manufacturing cost.
Solution Approach 2:
The patent changes the manufacturing approach by specifying plastic material parameters (refractive index 1.5-1.7, Abbe number 20-50) and aspheric surface parameters that can be directly molded, replacing the multi-step glass bonding process with a single molding operation that reduces cost while maintaining image quality.
4Reliability
If conventional camera lens is designed for high resolution, then image quality is improved, but overall size increases
Solution Approach 1:
The patent applies aspheric surface geometry (defined by conic constant and higher-order coefficients A4-A20) to the lens elements, particularly the fourth lens element, to correct spherical aberration and other optical imperfections. This allows for a more compact lens design with reduced total optical length while maintaining high image quality, eliminating the need for additional correction elements that would increase size.
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 lens assembly effectively corrects chromatic and spherical aberrations, reduces the total optical length, and is compact, suitable for integration into mobile devices while minimizing manufacturing costs.
Implementation Method 1
at least one of an object-side surface and an image-side surface of the fourth lens element is aspheric
Implementation Method 2
a first lens element with positive refractive power, a second lens element with negative refractive power, a third lens element with positive refractive power, and a fourth lens element with negative refractive power
Data Source
AI summary
An optical imaging lens assembly includes, in order from an object side to an image side, a first lens element with positive refractive power, a second lens element with negative refractive power, a third lens element with positive refractive power, and a fourth lens element with negative refractive power. The third lens element includes a convex image-side surface. The fourth lens element includes a concave image-side surface, and at least one of two surfaces of the fourth lens element is aspheric. Additionally, the optical imaging lens assembly also includes an aperture stop and an image sensor disposed at an image plane. By adjusting the relationship among the above-mentioned lens elements, the aperture stop, the image sensor and the image plane, the optical imaging lens assembly can effectively reduce the total optical length and correct the aberration as well as the chromatism to obtain superior imaging quality.