Camera Optical Lens Free-Form Surface Aberration Correction
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Solution Overview
Problem
Conventional camera lenses for handheld devices, such as smartphones and digital cameras, face challenges in achieving a large aperture, wide angle, and ultra-thinness while maintaining excellent optical performance due to insufficient refractive power distribution, lens spacing, and lens shape settings, particularly in correcting aberrations for wide-angle and ultra-wide-angle lenses.
Innovation Solution
A camera optical lens design incorporating free-form surfaces for at least one of its lenses, with specific focal length and curvature radius ratios, and on-axis thickness relationships, to optimize refractive power distribution and aberration correction, ensuring a large aperture, wide angle, and ultra-thinness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rotationally symmetric aspherical surface is used, then the lens structure is simple and easy to manufacture, but the aberration correction is insufficient for wide-angle applications
Solution Approach 1:
The patent applies asymmetry by transitioning from a rotationally symmetric aspherical surface to a free-form surface that is not rotationally symmetric. This allows the lens to correct aberrations more effectively in wide-angle applications while maintaining manufacturability through established free-form surface processing techniques.
Solution Approach 2:
The patent employs parameter changes by introducing specific focal length ratios (f2/f6 and f1/f) and curvature radius ratios (R1/R2, R3/R4, etc.) as design parameters. These parameter optimizations enable the lens to achieve both wide-angle coverage and effective aberration correction while controlling the overall optical length.
2Length of moving object
If the lens is made ultra-thin, then the device compactness is improved, but the optical performance and aberration correction deteriorate
Solution Approach 1:
The patent applies segmentation by dividing the optical system into eight separate lens elements with specific refractive power distributions. This segmentation allows each lens to be optimized for its specific function while achieving the overall ultra-thin requirement, with the sum of all lens thicknesses and spacing controlled to meet the ultra-thin criterion.
Solution Approach 2:
The patent employs dimensionality change by optimizing the lens spacing in the optical axis dimension while maintaining ultra-thin overall length. The specific spacing requirements (d5/d6 ratio and individual spacing values) ensure that light paths are properly managed within the constrained thickness, achieving both compactness and optical performance.
3Illumination intensity
If the aperture is enlarged, then the light gathering capability is improved, but the aberration and distortion increase
Solution Approach 1:
The patent applies local quality by assigning different refractive powers to different lens elements based on their specific positions and functions. Each lens element has optimized local characteristics (curvature radii and thicknesses) that contribute to correcting aberrations while maintaining a large aperture, with the first lens having specific curvature radius ratios R1/R2 to control aberration distribution.
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 design achieves good optical performance with a large aperture, wide angle, and ultra-thinness, effectively correcting on-axis and off-axis color aberrations, making it suitable for high-pixel CCD and CMOS camera lenses.
Implementation Method 1
a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens... at least one of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, or the eighth lens has a free-form surface
Data Source
AI summary
A camera optical lens includes, from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. At least one of the first lens to the eighth lens has a free-form surface, and the camera optical lens satisfies: −7.50≤f2/f6≤−1.50; and −6.00≤R1/R2≤−0.18, where f2 denotes a focal length of the second lens, f6 denotes a focal length of the sixth lens, R1 denotes a curvature radius of an object-side surface of the first lens, and R2 denotes a curvature radius of an image-side surface of the first lens. The camera optical lens has good optical performance, as well as a large aperture, ultra-thinness and a wide angle.