Optical Lens Assembly Aberration Correction via Aspheric Curvature
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Solution Overview
Problem
Conventional image-taking lens assemblies in mobile devices face challenges in miniaturization, image quality, and manufacturing complexity due to the use of multiple spherical lenses, which lead to increased optical length and unnecessary light reflections, affecting image quality.
Innovation Solution
An optical lens assembly comprising a front lens group with a negative refractive power and a rear lens group with specific refractive powers and aspheric surfaces, optimized by conditions such as R1/R2, f/f3, and SL/TTL ratios, to reduce optical length and correct aberrations while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple spherical lenses are used in the photographing lens assembly, then chromatic aberration can be corrected, but the total optical length becomes difficult to shorten and manufacturing complexity increases
Solution Approach 1:
The patent applies aspheric surfaces instead of traditional spherical surfaces for the lens elements. Specifically, the first lens element has an aspheric object-side surface and the second lens element has an aspheric image-side surface. This aspheric design allows for better control of optical paths and aberrations while enabling a more compact lens structure, directly resolving the contradiction between aberration correction and optical length reduction.
Solution Approach 2:
The patent changes the refractive index parameters and curvature parameters of the lens elements to optimize the optical system. By carefully selecting the refractive indices (n1, n2, n3, n4) and curvatures (R1, R2, R3, R4, R5, R6) of the four lens elements, the design achieves effective chromatic aberration correction in a compact configuration, addressing both the reliability and length constraints.
2Reliability
If multiple spherical lenses are bonded together, then chromatic aberration can be corrected, but manufacturing complexity and bonding difficulty increase
Solution Approach 1:
The patent divides the lens system into four separate lens elements (first lens element, second lens element, third lens element, and fourth lens element) with specific functions. Each lens element can be manufactured independently and then assembled, which simplifies the manufacturing process compared to bonding multiple spherical lenses together. The segmentation allows for easier quality control and assembly.
3Volume of moving object
If the lens assembly is miniaturized to fit in mobile devices, then compactness is achieved, but unnecessary light reflections occur in the lens barrel affecting image quality
Solution Approach 1:
The patent addresses the light reflection problem by strategically positioning the aperture stop and designing the lens elements to control light paths. The aspheric surfaces and specific curvature ratios (R1/R2, R3/R4) are optimized to minimize stray light reflections while maintaining compact size. This converts the potential harm of reflections into a controlled optical design that enhances image quality.
4Volume of moving object
If the lens assembly is miniaturized, then compactness is achieved, but image quality deteriorates due to light reflections and aberrations
Solution Approach 1:
The patent uses aspheric surfaces with specific curvature ratios (R1/R2 between -0.6 to -1.5, R3/R4 between 0.4 to 1.2) to control optical aberrations in the miniaturized lens assembly. This aspheric design effectively corrects spherical aberration, astigmatism, and other optical defects while maintaining a compact form factor, thus resolving the contradiction between size and image quality.
Solution Approach 2:
The patent optimizes multiple parameters including refractive indices, curvatures, and spacing between lens elements to achieve a balance between compactness and image quality. The specific parameter ranges (f/f3 between 0.5 to 2.0, SL/TTL between 0.3 to 1.5) are tuned to minimize aberrations and light reflections while maintaining a miniaturized structure.
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 effectively corrects spherical, astigmatic, and high-order aberrations, achieving improved image quality and compactness by balancing refractive power and reducing optical length, while allowing for the use of glass or plastic materials to optimize manufacturing and cost considerations.
Implementation Method 1
a first lens element with negative refractive power having a concave object-side surface, a second lens element with positive refractive power having a concave object-side surface and a convex image-side surface
Implementation Method 2
At least one of the object-side surface and the image-side surface of the forth lens element is aspheric
Data Source
AI summary
An optical lens assembly comprises, in order from an object side to an image side, a front lens group, a stop, and a rear lens group. The front lens group comprises a first lens element with negative refractive power having a concave object-side surface. The rear lens group comprises a second lens element with positive refractive power having a concave object-side surface and a convex image-side surface, a third lens element with positive refractive power, a fourth lens element with negative refractive power having a concave object-side surface and a convex image-side surface. At least one of two surfaces of the fourth lens element is aspheric. By adjusting the curvature radii of the object-side and the image-side surfaces of the first lens element and the focal lengths of the third lens element and the optical lens assembly, the length of the optical lens assembly is reduced, the aberration is corrected.