Five-Unit Zoom Lens Compact High Ratio Design
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving a compact form with high zoom ratios while maintaining high optical performance across the entire zoom range, particularly in setting refractive powers and movement loci of lens units.
Innovation Solution
A five-unit zoom lens configuration with specific refractive powers and movement patterns, where the second and third lens units move during zooming, and the first and fifth lens units remain stationary, with conditional expressions governing the focal lengths and movement ratios to optimize compactness and optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a five-unit zoom lens configuration is used to achieve high zoom ratio and compact size, then the zoom ratio and compactness are improved, but the optical performance across the entire zoom range deteriorates unless the refractive powers and movement loci are precisely optimized
Solution Approach 1:
The patent applies parameter changes by precisely optimizing the refractive powers of each lens unit (f1, f2, f3, f4, f5) and their movement amounts (M1, M2, M3, M4) during zooming. Specific conditional expressions define the relationships between these parameters, such as -1.52 ≤ f3/f4 ≤ -1.25 and 3.0 ≤ |M2/M3| ≤ 6.0, ensuring high optical performance is maintained across the entire zoom range while achieving compact size and high zoom ratio.
2Volume of moving object
If the second and third lens units are configured to move during zooming to achieve compact design, then the compactness is improved, but the complexity of determining movement loci and amounts increases
Solution Approach 1:
The patent applies segmentation by dividing the zoom lens into five independent lens units with distinct functions. The second lens unit (negative refractive power) and third lens unit (positive refractive power) are configured to move during zooming, while the first, fourth, and fifth units have different movement characteristics. This segmentation allows each unit to be optimized independently, simplifying the overall design complexity while achieving compact size.
Solution Approach 2:
The patent applies dynamics by configuring the second and third lens units to move during zooming operations. The movement amounts M2 and M3 are specifically optimized to satisfy conditional expressions, enabling dynamic adjustment of the optical system to maintain high optical performance across the zoom range while achieving compact design.
3Reliability
If the refractive powers of lens units are optimized to achieve high optical performance, then the optical performance is improved, but the difficulty of setting appropriate refractive powers and movement amounts increases
Solution Approach 1:
The patent provides specific parameter ranges and conditional expressions that guide the optimization process. For example, the refractive powers must satisfy -1.52 ≤ f3/f4 ≤ -1.25, and movement amounts must satisfy 3.0 ≤ |M2/M3| ≤ 6.0. These predefined parameter relationships simplify the design process by providing clear optimization targets, making it easier to manufacture while ensuring 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 enables the creation of a compact zoom lens with a high zoom ratio and high optical performance throughout the zoom range, effectively addressing the challenges of refractive power and movement unit settings.
Implementation Method 1
a second lens unit L2 having a negative refractive power, a third lens unit L3 having a positive refractive power
Data Source
AI summary
A zoom lens including, in order from an object side: a first positive lens unit; a second negative lens unit; a third positive lens unit; a fourth negative lens unit; and a fifth positive lens unit, wherein during zooming from a wide angle end, intervals between the adjacent lens units are changed in such a way that the second lens unit is configured to move from the object side to the image side and the third lens unit and the fourth lens unit are configured to move, and a focal length of the third lens unit, a focal length of the fourth lens unit, a movement amount of the second lens unit during zooming from the wide angle end to the telephoto end, and a movement amount of the third lens unit during zooming from the wide angle end to the telephoto end are appropriately set.