Imaging Lens Aspheric Design for Compact Low F-Value Aberration Correction
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Solution Overview
Problem
Existing imaging lenses for compact mobile devices face challenges in achieving low-profile and low F-value designs while maintaining high optical performance, particularly in aberration correction and image quality, due to the miniaturization of pixel size and increased demand for high pixelation.
Innovation Solution
The design incorporates a specific arrangement of lenses with aspheric surfaces, including a first lens with positive refractive power, multiple lenses with at least one aspheric surface, and an eighth lens with a concave surface and pole points off the optical axis, optimized by conditional expressions to achieve compactness, aberration correction, and high resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel size of the image sensor is reduced to achieve compactness and high pixelation, then the number of pixels increases and resolution improves, but the received luminous quantity per pixel decreases and noise increases
Solution Approach 1:
The patent changes the optical parameters of the lens system by reducing the F-value to F1.8 or less, which increases the aperture size relative to the focal length. This allows more light to reach each pixel, compensating for the reduced luminous quantity caused by smaller pixel sizes while maintaining high pixelation
2Illumination intensity
If the F-value is reduced to increase brightness and received luminous quantity, then illumination intensity improves, but the lens diameter increases and compactness deteriorates
Solution Approach 1:
The patent employs aspheric surfaces on multiple lens elements (second through seventh lenses have at least one aspheric surface, and the eighth lens has a double-sided aspheric structure). These curved surfaces enable more efficient light gathering and focusing, achieving high brightness with a compact lens diameter that would be impossible with traditional spherical surfaces
3Length of stationary object
If the lens is designed to be low-profile and compact, then the total track length is reduced and compactness improves, but aberration correction in the peripheral area becomes difficult and optical performance deteriorates
Solution Approach 1:
The patent divides the optical system into eight distinct lens groups with different functions and characteristics. The first lens has positive refractive power, the second through seventh lenses have varying powers with aspheric surfaces for specific aberration corrections, and the eighth lens has negative refractive power with a double-sided aspheric structure. This segmentation allows each group to address specific optical issues while maintaining overall compactness
Solution Approach 2:
Different lens elements are designed with specific local characteristics: the eighth lens has pole points positioned off the optical axis to correct peripheral aberrations, while other lenses have aspheric surfaces optimized for their specific positions in the optical path. This localized optimization ensures high optical performance across the entire field of view despite the compact form factor
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 enables a compact and low-profile imaging lens with a low F-value of F1.8 or less, effectively correcting aberrations and maintaining high optical performance, suitable for modern mobile devices with camera functions.
Implementation Method 1
a first lens L1 having positive refractive power and a convex surface on an object side near an optical axis, second lens L2, third lens L3, fourth lens L4, fifth lens L5, sixth lens L6, seventh lens L7 and eighth lens L8 having a concave surface on an image side near the optical axis as double-sided aspheric lens
Data Source
AI summary
A compact imaging lens which addresses low-profile and low F value, and corrects aberrations. An imaging lens includes a first lens having positive refractive power and a convex surface on an object side near an optical axis, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and a eighth lens having a concave surface on an image side near the optical axis as double-sided aspheric lens, wherein the second to seventh lenses each have at least one aspheric surface, and the eighth lens has pole points off an optical axis on the aspheric image-side surface.