Compact Imaging Lens Aberration Correction via Aspheric Design
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Solution Overview
Problem
Existing imaging lenses for compact devices face challenges in achieving a balance of low-profileness, wide field of view, and low F-value while effectively correcting aberrations, particularly in the peripheral area, leading to suboptimal optical performance.
Innovation Solution
The imaging lens configuration includes a first lens with strong positive refractive power, a second lens for correcting spherical and chromatic aberrations, a third double-sided aspheric lens for chromatic aberration correction, a fourth meniscus lens for field curvature correction, a fifth double-sided aspheric lens for distortion and field curvature control, and a sixth lens with an aspheric surface changing from convex to concave, ensuring proper aberration correction and maintaining low-profileness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional 6-lens imaging lens structure is used to achieve low-profileness and wide field of view, then the total track length is reduced and field of view is increased, but aberration correction in the peripheral area deteriorates
Solution Approach 1:
The patent applies local quality by using aspheric surfaces specifically on the third and sixth lenses where they are most needed for peripheral aberration correction. The aspheric surfaces are positioned at strategic locations in the optical path to address local aberration problems in the peripheral field of view while maintaining the overall compact structure.
Solution Approach 2:
The patent employs aspheric surfaces (non-spherical curvature) on specific lens surfaces to correct aberrations. The aspheric shapes allow for better control of light rays in the peripheral areas compared to traditional spherical surfaces, enabling improved aberration correction within the constrained total track length.
2Length of moving object
If the first lens is configured with stronger positive refractive power to ensure low-profileness and wide field of view, then the total track length is reduced and field of view is increased, but spherical aberration and chromatic aberration increase
Solution Approach 1:
The second lens acts as an intermediary element that corrects the spherical and chromatic aberrations generated by the first lens. By positioning the second lens with negative refractive power immediately after the first lens, it serves as a mediator to compensate for the aberrations introduced by the strong positive power of the first lens.
Solution Approach 2:
The patent uses composite lens design combining different materials with different Abbe numbers (dispersion properties). The third lens and fifth lens are made of materials with different Abbe numbers to correct chromatic aberrations while maintaining the strong positive refractive power needed for compact design.
3Manufacturing precision
If multiple aspheric lenses are used to correct aberrations, then aberration correction is improved, but the manufacturing complexity increases
Solution Approach 1:
Instead of making all six lenses aspheric, the patent applies aspheric surfaces only to the third and sixth lenses where they provide the most benefit for peripheral aberration correction. This selective application reduces manufacturing complexity while maintaining effective aberration correction.
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 balanced low-profileness, wide field of view, and low F-value, effectively correcting various aberrations and ensuring proper light ray control, thereby enhancing the optical performance of compact imaging devices.
Implementation Method 1
a third lens as a double-sided aspheric lens, a fourth lens having a meniscus shape with a concave surface facing the object side near an optical axis, a fifth lens as a double-sided aspheric lens, and a sixth lens having the concave surface facing the image side near an optical axis. The image-side surface of the sixth lens is an aspheric surface which changes to the convex surface at a peripheral portion
Implementation Method 2
20≤νd3/νd5 (where νd3: abbe number at d-ray of the third lens, νd5: abbe number at d-ray of the fifth lens)
Data Source
AI summary
There is provided an imaging lens with high-resolution which realizes the low-profileness, wide field of view and low F-value well balance. An imaging lens comprising in order from an object side to an image side, a first lens having positive refractive power, a second lens having negative refractive power, a third lens being a double-sided aspheric lens, a fourth lens having a meniscus shape with a concave surface facing the object side near an optical axis, a fifth lens being a double-sided aspheric lens, and a sixth lens having the concave surface facing the image side near the optical axis, wherein the image-side surface of said sixth lens is an aspheric surface which changes to the convex surface at a peripheral portion, and a total track length is 6.0 mm or less and below conditional expressions (2) and (3) are satisfied:20<νd3<32 (2)20<νd5<32 (3)whereνd3: abbe number at d-ray of the third lensνd5: abbe number at d-ray of the fifth lens.