Zoom Lens Refractive Power Distribution for Wide Angle and Compact Size
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving a high zoom ratio and wide angle of view while maintaining small size and high optical performance, due to limitations in the distribution of refractive powers among lens units and their movements during zooming.
Innovation Solution
A zoom lens configuration with a first positive refractive power unit, a second negative refractive power unit, a third positive refractive power unit, and a fourth positive refractive power unit, where the second unit includes two or more negative lenses, and the third unit moves monotonously towards the object side during zooming, with specific conditional expressions defining the focal length ratios to optimize refractive powers and minimize aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a conventional zoom lens configuration with positive, negative, positive, positive lens units is used, then the angle of view is widened, but the zoom ratio and optical performance are insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the focal length ratios between lens units through specific conditional expressions. The first conditional expression -1.05 < f2/f3 < -0.30 and the second conditional expression 2.10 < f2/fw < 3.50 define precise parameter ranges that enable achieving both wide angle of view and high optical performance with a zoom ratio of 6.0 or more.
2Device complexity
If the magnification varying burdens of the second, third, and fourth lens units are kept small, then the lens structure is simplified, but high zoom ratio and wide angle of view cannot be achieved
Solution Approach 1:
The patent changes the parameter distribution of magnification varying burdens among lens units. Specifically, it sets the third conditional expression 0.25 < M3/M2 < 0.75 and the fourth conditional expression 0.15 < M4/M2 < 0.60 to optimize the ratio relationships, enabling high zoom ratio and wide angle of view while maintaining manageable structural complexity.
Solution Approach 2:
The patent applies dynamics by defining specific movement trajectories for each lens unit during zooming. The second lens unit moves toward the image side then toward the object side, while the third lens unit moves monotonously toward the object side, creating dynamic optical path adjustments that achieve high zoom ratio with controlled complexity.
3Adaptability or versatility
If the zoom lens is designed for high zoom ratio and wide angle of view, then the functional requirements are met, but the lens size increases
Solution Approach 1:
The patent uses parameter changes to compact the lens design by optimizing focal length ratios and magnification varying burden ratios through conditional expressions, achieving high zoom ratio and wide angle of view while controlling the overall lens volume.
Solution Approach 2:
The patent applies nesting by arranging the positive, negative, positive, positive lens units in a compact configuration where inner lens units are positioned within the structural envelope of outer units, enabling high zoom ratio in a reduced overall lens size.
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 enables a zoom lens with a high zoom ratio and wide angle of view, maintaining a compact size and high optical performance by efficiently distributing refractive powers and correcting aberrations, thus addressing the limitations of previous designs.
Implementation Method 1
a zoom lens includes a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, a third lens unit L3 having a positive refractive power, and a fourth lens unit L4 having a positive refractive power that are arranged in order from an object side to an image side
Data Source
AI summary
In a zoom lens including a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a positive refractive power that are arranged in order from an object side to an image side, a movement locus of each of the lens units when zooming, a configuration of the second lens unit, a focal length of the second lens unit, a focal length of the third lens unit, and a focal length of the zoom lens at the wide angle end are set as appropriate.