Seven-Lens Optical Imaging Set Aberration Control
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Solution Overview
Problem
Conventional optical imaging lens sets for portable devices face challenges in achieving good imaging quality and reduced size due to significant spherical aberration and aberration issues, making it difficult to minimize lens length while maintaining performance, especially under dim light conditions.
Innovation Solution
A seven-lens element optical imaging lens set with specific refractive powers and surface shapes is designed, including a first lens with positive refractive power, a third lens with negative refractive power, and a sixth lens with a concave object-side surface and a convex image-side surface, along with optimized air gaps and thickness ratios to minimize total length and enhance image definition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the optical imaging lens set uses conventional design with seven lens elements, then the imaging quality can be maintained, but the total length from the object-side surface of the first lens element to the image plane becomes longer
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive indices, Abbe numbers, and curvature radii of the seven lens elements. Specifically, it sets the refractive index of the first lens element between 1.50-1.70, the second between 1.45-1.65, and controls the Abbe number of the sixth lens element to be 50 or higher. These parameter optimizations enable shorter focal lengths and reduced total length while maintaining imaging quality.
Solution Approach 2:
The patent uses composite material principles by selecting lens elements with different material properties. It combines lens elements with varying refractive indices and Abbe numbers, including the sixth lens element with high Abbe number (≥50) and the seventh with low Abbe number (≤30), to achieve chromatic aberration correction and improved imaging performance in a compact configuration.
2Length of stationary object
If the optical imaging lens set reduces the total length, then the device size is minimized, but the spherical aberration and aberration increase
Solution Approach 1:
The patent applies local quality by assigning specific surface shapes to specific lens elements. The sixth lens element has a concave object-side surface and convex image-side surface, while the seventh lens element has convex-convex surfaces. The aperture stop is positioned between the third and fourth lens elements to locally control ray bundles and reduce spherical aberration in the compact design.
Solution Approach 2:
The patent uses the aperture stop as an intermediary element positioned between the third and fourth lens elements. This aperture stop mediates the control of light rays, helping to reduce spherical aberration and other aberrations while allowing the overall lens length to be minimized through optimized spacing and curvature.
3Length of stationary object
If the optical imaging lens set minimizes the lens size, then the portable device becomes thinner, but the image definition deteriorates
Solution Approach 1:
The patent applies spheroidality by using aspherical surfaces on multiple lens elements. The first, second, third, fourth, fifth, sixth, and seventh lens elements all incorporate aspherical surfaces with specific curvature profiles. This allows for better control of off-axis rays and improved image definition across the field of view while maintaining a compact lens size suitable for portable devices.
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 a shorter lens length with improved imaging quality and reduced aberrations, ensuring better performance under various lighting conditions and facilitating easier fabrication.
Implementation Method 1
The first lens element has positive refractive power, the second lens element has positive refractive power, the third lens element has negative refractive power
Data Source
AI summary
An optical lens set includes: a first, second, third, fourth, fifth, sixth and seventh lens element, said first lens element has positive refractive power, said second lens element has positive refractive power, said third lens element has negative refractive power, said sixth lens element has an object-side surface with a concave part in a vicinity of the optical axis, and said seventh lens element has an image-side surface with a concave part in a vicinity of the optical axis. The optical lens set does not include any lens element with refractive power other than said first, second, third, fourth, fifth, sixth and seventh lens elements. In addition, υ6 is the Abbe number of the sixth lens element, and the optical lens set satisfies the relationship: υ6≥50.