Seven-element optical imaging lens with aspheric surfaces and Abbe number constraints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge is to design an optical imaging lens that maintains good image quality and a large aperture stop while having a shortened length, which is difficult to achieve by simply scaling down existing lenses, as it requires balancing optical performance, field of view, and manufacturing considerations, including spherical aberration, field curvature, and distortion.
Innovation Solution
The optical imaging lens is composed of seven elements arranged along the optical axis, with specific refracting powers and surface shapes, including aspheric surfaces, to optimize image quality and field of view, and the Abbe numbers of these elements are constrained to ensure effective chromatic aberration correction, allowing for a compact design with a large aperture stop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the length of optical imaging lens is shortened, then the compact design requirement is met, but the optical performance and image quality deteriorate
Solution Approach 1:
The optical imaging lens is divided into seven separate lens elements with different refracting powers and surface shapes. Each lens element contributes to correcting specific optical aberrations, allowing the system to maintain high optical performance in a compact form. The segmentation enables distributed correction of spherical aberration, field curvature, and distortion across multiple elements rather than requiring a single long lens.
Solution Approach 2:
The patent employs aspheric surfaces on multiple lens elements (fifth, sixth, and seventh elements) to correct optical aberrations more effectively than spherical surfaces. The aspheric surfaces allow for better control of light rays, improving image quality while maintaining a shorter overall lens length. This curvature variation is critical for achieving compact design without sacrificing optical performance.
2Manufacturing precision
If seven lens elements are used to improve spherical aberration, field curvature, and distortion, then image quality improves, but color distortion on the periphery increases and device complexity increases
Solution Approach 1:
Different lens elements are assigned specific local functions to correct particular types of aberrations. The first four elements with positive refracting power address spherical aberration and field curvature in specific regions, while the fifth element with negative refracting power and aspheric surfaces targets peripheral distortion and color correction. This localized approach to aberration correction allows the system to improve overall image quality while minimizing color distortion through targeted design of each element's surface shape and material properties.
Solution Approach 2:
The patent carefully selects and controls the Abbe numbers of the lens elements (V4+V5+V6+V7≤175.00) to manage chromatic aberration and color distortion. By changing the optical parameters of each element, particularly using materials with different dispersion properties, the system corrects color distortion on the periphery while maintaining the benefits of seven-element design for overall image quality.
3Illumination intensity
If the aperture stop is enlarged, then the field of view and light gathering ability improve, but the lens length and manufacturing difficulty increase
Solution Approach 1:
The optical design incorporates dynamic optimization of the aperture stop position and size relative to the seven lens elements. The arrangement allows the aperture stop to be effectively enlarged for better light gathering and field of view while the distributed lens elements manage the increased complexity. The fifth element with negative refracting power and aspheric surfaces helps control the light paths from the enlarged aperture, maintaining compact length despite the larger aperture requirement.
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 results in an optical imaging lens with improved image quality, a broadened field of view, and a reduced length, while maintaining good optical performance and ease of production, addressing the limitations of existing lens designs.
Implementation Method 1
at least one of the object-side surface and the image-side surface of the fifth lens element is an aspheric surface; the object-side surface and the image-side surface of the seventh lens element are both aspheric surfaces
Implementation Method 2
V4+V5+V6+V7≤175.00, wherein V4 is an Abbe number of the fourth lens element; V5 is an Abbe number of the fifth lens element; V6 is an Abbe number of the sixth lens element; and V7 is an Abbe number of the seventh lens element
Data Source
AI summary
An optical imaging lens includes a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element arranged in order from an object side to an image side along an optical axis. Each lens element has an object-side surface and an image-side surface. The optical imaging lens satisfies: V4+V5+V6+V7≤175.00, wherein V4 is an Abbe number of the fourth lens element, V5 is an Abbe number of the fifth lens element, V6 is an Abbe number of the sixth lens element, and V7 is an Abbe number of the seventh lens element.