Three-Group Zoom Lens with Fixed Aperture Stop
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Solution Overview
Problem
Conventional zoom lenses using two or more lens groups often sacrifice resolution at certain focal lengths, while those with four or more groups require complex and costly mechanisms, failing to maintain optimal image quality across all focal lengths.
Innovation Solution
A zoom lens design featuring three lens groups with a fixed aperture stop between the first and second groups, allowing the first lens group to move while the aperture stop remains stationary, optimizing image quality at telephoto, wide-angle, and middle positions while reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a zoom lens uses two groups of lens set, then the device complexity is reduced, but the image quality (resolution) cannot be optimized simultaneously at all focal lengths
Solution Approach 1:
The zoom lens is divided into three distinct lens groups (first, second, and third lens groups) with different optical powers. This segmentation allows each group to contribute differently to the overall optical performance, enabling good image quality across wide-angle, middle, and telephoto focal lengths while keeping the total number of groups manageable.
Solution Approach 2:
Each lens group is assigned specific local optical characteristics: the first lens group has positive optical power, the second has negative optical power, and the third has positive optical power. This local differentiation of optical properties allows the system to optimize image quality at different focal lengths without requiring all lens groups to be identical or overly complex.
2Manufacturing precision
If a zoom lens uses four or more groups of lens set, then the image quality is improved, but the manufacturing cost increases due to complex driving mechanism
Solution Approach 1:
The zoom lens is divided into three distinct lens groups (first, second, and third lens groups) with different optical powers. This segmentation allows each group to contribute differently to the overall optical performance, enabling good image quality across wide-angle, middle, and telephoto focal lengths while keeping the total number of groups manageable.
Solution Approach 2:
The patent specifies particular parameter ranges for the lens groups, including optical power relationships (0.3 < |f2/f1| < 1.0 and 0.3 < |f2/f3| < 1.0) and focal length ratios (0.65 < |f3/f1| < 1.30). By optimizing these parameters within specific ranges, the system achieves high image quality with only three lens groups, avoiding the need for four or more groups and their associated complex driving mechanisms.
3Manufacturing precision
If the aperture stop moves during zooming, then the optical performance may be improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The aperture stop is merged with a fixed structural component of the lens system rather than being implemented as a separate movable element. By positioning the aperture stop at a fixed location between the first and second lens groups, its function is integrated into the static structure, eliminating the need for additional driving mechanisms while maintaining optimal optical performance across all focal lengths.
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 three-group lens design improves image quality across all focal lengths and reduces manufacturing costs compared to conventional four-group designs, while incorporating lenses with high Abbe numbers and aspheric lenses to enhance performance and correct aberrations.
Implementation Method 1
a first lens group having positive optical power, a second lens group having negative optical power, and a third lens group having positive optical power
Data Source
AI summary
A zoom lens is provided. The zoom lens includes a first lens group, a second lens group, a third lens group and an aperture stop. The second lens group is disposed between the first lens group and the third lens group. The aperture stop is disposed between the first lens group and the second lens group. When the zoom lens zooms, the aperture stop is fixed without moving and the first lens group correspondingly moves.