Optical System Aberration Correction via Lens Parameter Optimization
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Solution Overview
Problem
Existing image pickup optical systems with large aperture ratios face challenges in achieving high image quality and good blur quality due to uncorrected aberrations such as chromatic aberration, spherical aberration, and astigmatism, while also requiring a larger system size, which is difficult to downsize effectively.
Innovation Solution
An optical system configuration comprising a front lens group with at least one positive lens and one negative lens, where specific focal length and distance ratios are maintained to optimize refractive powers and reduce aberrations, allowing for a large aperture ratio while minimizing system size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the aperture ratio is increased to achieve high image quality, then the image quality is improved, but the system size becomes larger
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive powers of positive and negative lenses, their focal lengths, and their distances from the aperture stop. By optimizing parameters such as the focal length of the positive lens (fLp), the distance from the positive lens to the aperture stop (Dps), and the focal length of the negative lens (fLn), the system achieves large aperture ratio while maintaining compact size through mathematical relationships defined in conditional expressions.
Solution Approach 2:
The patent implements local quality by assigning specific optical properties to different lens elements. The positive lens closest to the object side and the negative lens closest to the image side are given specific refractive powers and focal lengths that differ from other lenses in the system. This localized optimization of lens properties allows the system to control aberrations and reduce size while maintaining large aperture ratio.
2Volume of moving object
If the refractive powers of positive lenses are increased to reduce the aperture stop diameter, then the system size is reduced, but spherical aberration and other aberrations increase
Solution Approach 1:
The patent applies segmentation by dividing the optical system into distinct positive and negative lens groups with specific functions. The positive lens (Lp) and negative lens (Ln) are separated and assigned different refractive powers and positions relative to the aperture stop. This segmentation allows each lens group to address specific aberration types while working together to reduce overall system size, preventing the spherical aberration that would result from simply increasing positive lens power alone.
Solution Approach 2:
The patent converts the potentially harmful effect of high refractive power (which causes spherical aberration) into a benefit by using a combination of positive and negative lenses. The negative lens compensates for the spherical aberration introduced by the positive lens, while both lenses work together to reduce the aperture stop diameter. This transforms the harmful aberration-generating property into a useful size-reduction mechanism when properly balanced.
3Manufacturing precision
If various aberrations are corrected to achieve good blur quality, then the blur quality is improved, but the device complexity increases
Solution Approach 1:
The patent uses parameter changes to correct aberrations by optimizing specific lens parameters rather than adding complex optical elements. By adjusting the focal lengths, refractive powers, and positions of the positive and negative lenses according to defined conditional expressions, the system achieves excellent aberration correction including spherical aberration, coma, and astigmatism, while maintaining relatively simple 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
The solution effectively corrects spherical aberration and other aberrations, achieving high optical performance while downsizing the entire lens system, even with a large aperture ratio, by optimizing the refractive powers and distances within the optical system.
Implementation Method 1
a positive lens Lp arranged closest to the object side among the at least one positive lens
Implementation Method 2
a negative lens Ln arranged closest to the image side among the at least one negative lens
Data Source
AI summary
Provided is an optical system consisting of, in order from an object side to an image side, a front lens group (FLG), an aperture stop and a rear lens group (RLG), in which FLG includes at least one positive lens and at least one negative lens. A focal length of a positive lens Lp arranged closest to object side among the at least one positive lens, a focal length of a negative lens Ln arranged closest to image side among the at least one negative lens, a distance on an optical axis from an object-side lens surface of positive lens Lp to aperture stop, a distance on optical axis from an object-side lens surface of negative lens Ln to aperture stop, and a distance on optical axis from aperture stop to a lens surface closest to image side in RLG when focused at infinity are appropriately set.