Zoom Lens Layout With Fixed Front Group and Air Lens Aberration Control
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving a compact and lightweight design with high optical performance, large aperture ratio, and high-speed zoom operation while maintaining high image quality, due to issues with lens diameter and aberration correction.
Innovation Solution
The zoom lens design includes a first lens unit fixed relative to the image plane during zooming, with a specific configuration of lens units and air gaps to reduce front lens diameter, and a rear group with moving lens units to correct aberrations, adhering to specific inequalities for lens radii and focal lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the F-number is reduced to achieve a large aperture ratio, then the light gathering ability is improved, but the lens diameter increases making the system larger and heavier
Solution Approach 1:
The lens system is divided into multiple lens units with different refractive powers arranged in specific groups. The first lens unit has positive refractive power, the second has negative refractive power, and the third has positive refractive power. This segmentation allows the system to achieve large aperture ratio while controlling overall lens diameter and weight through optimized power distribution across segments.
Solution Approach 2:
The patent optimizes specific parameters including the refractive indices and curvatures of lens surfaces. The inequalities provided constrain the radii of curvature (r111, r112) and focal lengths (f1, f2) to achieve the desired balance between aperture ratio, lens diameter, and weight. By carefully adjusting these parameters within the specified ranges, the system achieves high performance without excessive size or weight.
2Area of stationary object
If the refractive power of the second lens unit is increased to reduce front lens diameter, then the lens size is reduced, but high image quality becomes difficult to achieve
Solution Approach 1:
The lens is segmented into multiple units with specific refractive power assignments. The second lens unit has negative refractive power and is positioned between the first and third lens units. This segmentation allows the system to achieve compact diameter while distributing aberration correction across multiple units, maintaining high image quality.
Solution Approach 2:
The patent employs a composite lens structure combining multiple lens materials with different refractive indices and dispersion characteristics. The specific configuration of lens units with alternating positive and negative powers creates a composite optical system that corrects various aberrations while maintaining compact size and high image quality.
3Manufacturing precision
If multiple lens units are added to correct aberrations, then optical performance is improved, but device complexity increases
Solution Approach 1:
The lens system is divided into three main lens units with specific refractive power assignments, plus a rear group. This segmentation provides a systematic approach to aberration correction where each unit handles specific optical functions. The modular structure makes the complex system more manageable and easier to manufacture.
Solution Approach 2:
Each lens unit is designed to perform multiple functions: the first lens unit provides positive refractive power and helps control coma, the second lens unit provides negative refractive power and corrects distortion, and the third lens unit provides positive refractive power and contributes to spherical aberration correction. This multi-functionality reduces the need for additional specialized elements.
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 achieves a compact, lightweight zoom lens with high image quality, large aperture ratio, and high-speed zoom operation by effectively correcting various aberrations and reducing lens diameter.
Implementation Method 1
An air lens is formed by an air gap between the single lens and a lens adjacent to and disposed on the image side of the single lens
Data Source
AI summary
A zoom lens includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, and a rear group. A distance between adjacent lens units changes during zooming from a wide-angle end to a telephoto end. The first lens unit is fixed relative to an image plane during zooming from the wide-angle end to the telephoto end. The first lens unit includes single lens having negative refractive power closest to an object, and a plurality of lenses having positive refractive powers disposed on the image side of the single lens. An air lens is formed by an air gap between the single lens and a lens adjacent to and disposed on the image side of the single lens. A predetermined inequality is satisfied.