Imaging Lens Aspheric Aberration Correction
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Solution Overview
Problem
Existing imaging lenses struggle to achieve a balance between wide field of view, low-profileness, and low F-number while effectively correcting aberrations, especially in peripheral areas.
Innovation Solution
The imaging lens configuration includes a first lens with a convex surface, a second lens, a third lens with negative refractive power, and subsequent lenses, with the eighth lens having a concave surface and an aspheric surface with pole points off the optical axis, to properly correct spherical aberration, astigmatism, and chromatic aberration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional lens configurations are used to achieve wide field of view, low-profileness and low F-number, then compactness and high performance are improved, but aberration correction in peripheral areas deteriorates
Solution Approach 1:
The patent applies aspheric surfaces to multiple lens elements (first, fourth, fifth, and eighth lenses) to correct aberrations in peripheral areas while maintaining wide field of view. The aspheric coefficients are specifically optimized to control spherical aberration, coma, and distortion, resolving the contradiction between wide field of view and aberration correction capability.
Solution Approach 2:
The patent uses composite lens structures with different refractive indices and Abbe numbers (e.g., first lens with Nd=1.5445, νd=55.86; third lens with Nd=1.6711, νd=9.48) to correct chromatic aberration and other optical imperfections. This composite approach enables simultaneous achievement of wide field of view and excellent aberration correction.
2Length of stationary object
If conventional lens configurations are used to achieve low-profileness, then compactness is improved, but peripheral aberration correction deteriorates
Solution Approach 1:
The patent employs aspheric surfaces on multiple lens elements to correct peripheral aberrations within a compact total track length. The aspheric coefficients are optimized to maintain image quality while minimizing the overall lens length, achieving both low-profileness and excellent aberration correction.
Solution Approach 2:
The patent applies different aspheric coefficients to different lens elements based on their specific positions and functions. For example, the first lens has aspheric coefficients A4=-0.00328, A6=0.0309, while the fourth lens has A4=-0.0596, A6=0.542, tailoring the local optical properties to correct aberrations at specific locations while maintaining compact overall dimensions.
3Use of energy by moving object
If conventional lens configurations are used to achieve low F-number, then light gathering capability is improved, but aberration correction deteriorates
Solution Approach 1:
The patent uses aspheric surfaces on multiple lens elements to correct spherical aberration and coma that become more pronounced at low F-numbers. The aspheric coefficients are specifically optimized to maintain excellent aberration correction while achieving low F-number for enhanced light gathering capability.
Solution Approach 2:
The patent employs composite lens structures with carefully selected refractive indices and Abbe numbers to correct chromatic aberration and other optical imperfections at low F-number. This enables simultaneous achievement of high light gathering capability and excellent aberration correction across the entire field of view.
4Manufacturing precision
If more lens elements are added to improve aberration correction, then optical performance is improved, but device complexity increases
Solution Approach 1:
The patent uses aspheric surfaces on strategically selected lens elements (first, fourth, fifth, and eighth lenses) to achieve excellent aberration correction without adding excessive complexity. This targeted application of aspheric surfaces provides high-resolution performance while maintaining a manageable lens configuration.
Solution Approach 2:
The patent optimizes specific parameters of existing lens elements, such as refractive indices, Abbe numbers, and aspheric coefficients, to achieve superior aberration correction. By carefully controlling parameters like the ratio of focal lengths and Abbe numbers between adjacent lenses, the patent achieves high performance without significantly increasing device complexity.
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 achieves high-resolution imaging with a wide field of view, low-profileness, and low F-number, while effectively correcting aberrations across the entire image field.
Implementation Method 1
The image-side surface of the eighth lens is formed as an aspheric surface having at least one pole point in a position off the optical axis. When the image-side surface of the eighth lens is formed as the aspheric surface, the field curvature and the distortion can be properly corrected and a light ray incident angle to an image sensor can be properly controlled.
Data Source
AI summary
There is provided an imaging lens with high-resolution which satisfies demand of the wide field of view, the low-profileness and the low F-number, and excellently corrects aberrations. An imaging lens comprises in order from an object side to an image side, a first lens having a convex surface facing the object side near an optical axis, a second lens, a third lens having negative refractive power near the optical axis, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens having a concave surface facing the image side and the negative refractive power near the optical axis, wherein an image-side surface of said eighth lens is formed as an aspheric surface having at least one pole point in a position off the optical axis, said sixth lens has positive refractive power near the optical axis, an object-side surface of said seventh lens is a convex surface facing the object side near the optical axis, and a below conditional expression (1) is satisfied:0.15<νd7/νd8<0.55whereνd7: an abbe number at d-ray of the seventh lens,νd8: an abbe number at d-ray of the eighth lens.