Aspheric Lens System Aberration Correction
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Solution Overview
Problem
Conventional miniaturized optical lens systems for mobile phone cameras face challenges in reducing volume and correcting aberrations due to limited space and material constraints, particularly when the lens assembly is less than 3 mm in length, leading to poor image quality and uniformity issues.
Innovation Solution
An optical lens system comprising two aspheric lens elements with specific refractive indices and focal lengths, where the first lens element provides most of the positive refractive power and the second lens element corrects aberrations, allowing for a telecentric design and reduced total track length, effectively utilizing plastic materials for cost-effectiveness and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If three lens elements are used to correct aberrations, then image quality is improved, but the lens assembly length increases and volume increases
Solution Approach 1:
The patent merges the functions of multiple lens elements into a two-element design by strategically positioning the aperture stop between the first and second lens elements. This configuration allows the first lens element to provide positive refractive power while the second lens element corrects aberrations, achieving effective aberration correction with fewer elements and reduced length.
Solution Approach 2:
The patent introduces a new design dimension by placing the aperture stop in a specific position between the two lens elements, rather than at the traditional locations. This dimensional repositioning enables better control over light paths and aberration correction, allowing high image quality in a compact form factor.
2Volume of stationary object
If lens elements are made thinner to reduce volume, then miniaturization is achieved, but uniformity and manufacturing quality deteriorate
Solution Approach 1:
The patent optimizes key parameters including the refractive indices of the lens elements (N1 and N2 satisfying specific relationships), the position of the aperture stop, and the focal length ratios. These parameter optimizations enable the lens elements to maintain adequate thickness for manufacturing uniformity while achieving miniaturization through efficient optical design.
3Ease of manufacture
If plastic material is used for lens elements to reduce cost, then manufacturing cost decreases, but achieving high precision becomes more difficult
Solution Approach 1:
The patent specifies precise parameter relationships for plastic lens elements, including refractive index ranges (N1 and N2 satisfying specific inequalities), aspheric surface coefficients, and focal length ratios. These controlled parameter variations enable plastic injection molding to achieve high precision lens elements with consistent quality across production batches.
Solution Approach 2:
The patent employs aspheric surfaces on both the object-side and image-side of each lens element. The aspheric coefficients are carefully optimized to correct spherical aberration and other optical imperfections, enabling plastic lens elements to achieve glass-level precision through injection molding.
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 proposed optical lens system improves image quality, reduces volume, and corrects aberrations, achieving a balanced refractive power distribution while maintaining miniaturization and cost-effectiveness, enhancing the performance of mobile phone camera lenses.
Implementation Method 1
a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface
Implementation Method 2
the object-side and the image-side surfaces of the first lens element being aspheric; and a second lens element with positive refractive power having a convex object-side surface and a concave image-side surface, the object-side and the image-side surfaces of the second lens element being aspheric
Data Source
AI summary
An optical lens system for taking image comprises, in order from an object side to an image side: a first lens element with positive refractive power having an aspheric convex object-side surface and an aspheric concave image-side surface; a second lens element with positive refractive power having an aspheric convex object-side surface and an aspheric concave image-side surface. Radii of curvature of the object-side surface of the first lens element, the object-side and image-side surfaces of the second lens element are R1, R3 and R4 respectively, focal lengths of the optical lens system for taking image, the first and second lens elements are f, f1, f2 respectively, an on-axis distance between the first and second lens elements is T12, a center thickness of the second lens element is CT2, they satisfy the relations: 0.76 mm−1<1/R1<2.0 mm−1; 0.4<R3/R4<1.15; 0.35<(f/f1)−(f/f2)<0.72; T12/CT2>1.0.