Five-Unit Zoom Lens Design for High Magnification and Weight Reduction
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Solution Overview
Problem
Current zoom lenses for broadcasting, cinema, and digital cameras face challenges in achieving high magnification while minimizing size and weight, while maintaining good optical performance, especially with the requirement for a wide angle of view and high zooming ratio.
Innovation Solution
A five-unit zoom lens design is implemented, comprising a first lens unit with positive refractive power that does not move, a second and third lens unit with negative and positive refractive power that move during zooming, and a fourth and fifth lens unit with negative and positive refractive power that do not move, respectively, with specific conditional expressions governing the intervals and focal lengths to optimize magnification and weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a five-unit zoom lens with moving lens units is used to achieve high magnification and wide angle of view, then the zooming ratio and angle of view are improved, but the size and weight of the lens increase
Solution Approach 1:
The zoom lens is divided into five distinct lens units (first through fifth lens units) with different refractive powers, where only the second, third, and fourth lens units move during zooming. This segmentation allows high magnification to be achieved through coordinated movement of specific units rather than moving the entire lens assembly, thereby reducing overall weight while maintaining zooming capability.
Solution Approach 2:
The patent implements dynamic zooming by moving only the second, third, and fourth lens units along the optical axis while keeping the first and fifth lens units fixed. This dynamic configuration allows the lens to achieve high zooming ratios without requiring all components to be movable, thus reducing weight while maintaining adaptability across different focal lengths.
2Reliability
If more lens units are added to achieve high magnification and correct aberrations, then optical performance is improved, but device complexity increases
Solution Approach 1:
The five-unit zoom lens divides the optical system into distinct functional segments: the first lens unit (positive refractive power) for initial focusing, the second lens unit (negative refractive power) for zooming assistance, the third lens unit (positive refractive power) for image formation, the fourth lens unit (negative refractive power) for aberration correction, and the fifth lens unit (positive refractive power) for final focusing. This segmentation enables effective aberration correction while maintaining manageable structural complexity through clear functional separation.
3Volume of moving object
If the interval between lens units is reduced to decrease lens size, then compactness is improved, but aberration correction capability deteriorates
Solution Approach 1:
The patent employs dynamic interval adjustment between lens units during zooming operations. The second, third, and fourth lens units move along the optical axis with precisely controlled intervals that vary according to the zoom position. This dynamic spacing allows the lens to maintain compact size at each focal length while preserving sufficient separation between lens units to correct optical aberrations effectively at all zoom positions.
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 design achieves high magnification, reduces size and weight, and maintains good optical performance by carefully controlling the movement and positioning of lens units to correct aberrations and maintain image quality across the zoom range.
Implementation Method 1
a five-unit zoom lens including five lens units as a whole, in which a lens unit having a positive refractive power is arranged at the end on an object side
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3~4A
AI summary
A zoom lens, including, in order from object side, a positive first unit, a negative second unit, a positive third unit, a negative fourth unit, and a positive fifth unit. The first unit includes, in order from object side, a negative first sub unit which does not move for focusing, a positive second sub unit which moves during focusing, and a positive third sub unit which does not move for focusing and includes a negative lens. 1.6<L2tm/L2t<1000.0; L2w/L3w<1.0; and -0.5<f2/f3<-0.05 are satisfied, where L2t represents an second-third unit interval at a telephoto end, L2tm represents second-third unit interval at a zoom position at which an interval between the third and fourth units is minimum, L2w represents second-third unit interval at a wide-angle end, L3w represents third-fourth unit interval at the wide-angle end, and f2 and f3 represent focal lengths of the second and third units, respectively.