Negative-lead Zoom Lens Aberration Control via Parameter Optimization
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Solution Overview
Problem
Negative-lead zoom lenses face challenges in achieving a high zoom ratio and large field angle while maintaining optical performance across the entire zooming range, as increasing refractive power leads to aberration variations and difficulty in correcting chromatic aberrations.
Innovation Solution
A zoom lens system with a first lens unit having a negative optical power and a second lens unit with a positive optical power, where the distance between these units changes during zooming, and specific conditions are met for the Abbe numbers and focal lengths of the lens elements to minimize aberrations, including the use of suitably selected materials and aspherical surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the refractive power of each lens unit is increased to reduce the overall size of the negative-lead zoom lens, then the overall size is reduced, but aberrations largely vary during zooming and it becomes difficult to obtain high optical performance
Solution Approach 1:
The patent applies parameter changes by carefully selecting the Abbe numbers and refractive indices of the lens materials, and by setting the focal length of the first lens unit within a specific range. These parameter optimizations allow the lens system to maintain high optical performance across the zoom range while keeping the overall size compact, resolving the contradiction between size reduction and aberration control
Solution Approach 2:
The patent uses composite material principles by combining lens elements with different Abbe numbers (v1p for positive lens and v1n for negative lens) and refractive indices. This composite approach allows for chromatic aberration correction while maintaining the compact size and high zoom ratio, enabling the system to achieve both small volume and high optical performance
2Adaptability or versatility
If the field angle and zoom ratio are increased to enhance functionality, then the versatility is improved, but aberration variations during zooming are increased and it becomes difficult to obtain high optical performance
Solution Approach 1:
The patent achieves high field angle and zoom ratio while maintaining optical performance by optimizing key parameters: setting the focal length of the first lens unit (f1) within a specific range relative to the wide-angle focal length (fw), and selecting lens materials with appropriate Abbe numbers. These parameter changes enable the lens to correct aberrations effectively across the entire zoom range
Solution Approach 2:
The patent employs dynamic design in the movement characteristics of the lens units during zooming. The first and second lens units move in a coordinated manner with specific distance relationships maintained at different zoom positions, allowing the system to adapt to varying field angles and zoom ratios while maintaining optimal optical performance throughout the range
3Reliability
If an adequate lens structure is used in the first lens unit to reduce aberration variations, then the optical performance is improved, but the device complexity increases
Solution Approach 1:
The patent achieves high optical performance with a relatively simple lens structure by optimizing parameters rather than adding complexity. Specifically, the focal length of the first lens unit is set within a specific range (0.08fw to 0.15fw), and lens materials are selected based on Abbe number requirements. This parameter-based approach corrects chromatic aberration and reduces aberration variations without requiring complex multi-element designs
Solution Approach 2:
The patent extracts and focuses the chromatic aberration correction function primarily on the first lens unit by selecting materials with appropriate Abbe numbers. This concentration of the correction function in a simple two-element first lens unit avoids the need for complex aberration correction mechanisms throughout the entire lens system, thereby maintaining simplicity while achieving high optical performance
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 allows for a compact zoom lens system with a high zoom ratio and large field angle, effectively correcting aberrations over the entire zooming range without increasing the overall size, ensuring high optical performance.
Implementation Method 1
The first lens unit includes a positive lens element and a negative lens element made of suitably selected materials... a focal length of the first lens unit is adequately set, so that the following conditions are satisfied: v1p and v1n are Abbe numbers of materials of the positive and negative lens elements, respectively
Data Source
AI summary
A zoom lens system includes a first lens unit having a negative optical power and a second lens unit having a positive optical power in order from the object side to the image side. In a zooming operation, the distance between the first lens unit and the second lens unit at the telephoto end is smaller than that at the wide angle end. The first lens unit includes a single negative lens element and a single positive lens element, and materials of the lens elements are adequately set.