Zoom Lens System Aberration Control Miniaturization
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Solution Overview
Problem
Miniaturized zoom lenses for electronic imaging devices, such as surveillance cameras, face challenges in achieving a wide view angle with low aberration while maintaining miniaturization and high pixel image capabilities, particularly in dark environments where optical aberration compensation is crucial.
Innovation Solution
A zoom lens system comprising a first lens group with negative refractive power and a second lens group with positive refractive power, where the lens groups move relative to each other during zooming, with specific refractive index and Abbe number conditions met to minimize aberrations, and including aspheric surfaces to enhance resolution and compensate for chromatic and spherical aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the zoom lens is miniaturized to reduce size, then the lens size is reduced, but the ability to achieve wide view angle with low aberration deteriorates
Solution Approach 1:
The zoom lens is divided into multiple lens groups (first lens group with negative refractive power, second lens group with positive refractive power, and additional lens groups) that can move independently relative to each other. This segmentation allows each group to be optimized for specific functions (wide angle performance, aberration correction) while enabling compact overall design through coordinated movement of smaller modular units.
Solution Approach 2:
The patent employs aspheric surfaces on lens elements, which introduce a dimensional change from traditional spherical surfaces. This allows for more efficient control of light paths and aberrations in a compact configuration, enabling wide view angles and low distortion without increasing lens size.
2Illumination intensity
If the lens is designed for wide angle with low F-number, then the view angle and brightness are improved, but optical aberration increases
Solution Approach 1:
Different lens groups are assigned specific refractive powers and material properties tailored to their local functions. The first lens group has negative refractive power optimized for wide angle control, while the second lens group has positive refractive power for focusing. Specific lens elements use materials with particular Abbe numbers to correct chromatic aberration locally, allowing the overall system to achieve low F-number with controlled aberrations.
Solution Approach 2:
The patent specifies precise parameter ranges for refractive indices (e.g., 1.58 < nd21) and Abbe numbers (e.g., vd22 ≥ 20, v(G2+) > 50) of lens materials. By carefully selecting and controlling these optical parameters, the design achieves the desired brightness (low F-number) while maintaining aberration correction through material property optimization.
3Manufacturing precision
If more lens elements are added to improve resolution, then the image quality is improved, but the lens size and complexity increase
Solution Approach 1:
The patent incorporates aspheric surfaces on specific lens elements, which replace traditional spherical surfaces. This allows for more efficient correction of spherical aberration and other monochromatic aberrations, achieving high resolution with fewer lens elements compared to conventional spherical designs, thereby reducing overall complexity.
Solution Approach 2:
The patent replaces some mechanical lens elements with optical equivalents through the use of aspheric surfaces and carefully selected material properties. This substitution reduces the number of discrete moving parts and simplifies the mechanical structure while maintaining or improving image resolution through enhanced optical design.
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 provides a bright zoom lens system with a wide view angle, effective aberration compensation, and high resolution, enabling clear imaging in dark and wide areas, suitable for surveillance applications.
Implementation Method 1
a first lens group having negative refractive power; and a second lens group having positive refractive power
Implementation Method 2
The second lens group may include at least one aspheric surface
Data Source
AI summary
A zoom lens system including, in an order from an object to an image: a first lens group having negative refractive power; and a second lens group having positive refractive power, wherein the zoom lens system satisfies equations: i) 1.2≦̸Fnow≦̸2.2; ii) 2.5<ft/fw≦̸3; and iii) BFL≧6 mm, where Fnow denotes an F-number at a wide angle position, ft and fw respectively denotes overall focal lengths at a telephoto position and the wide angle position, and BFL denotes a back focal length.