Zoom Lens with Single-Element Third Unit for Compact High-Ratio Design
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving a high zoom ratio, wide angle of view, and high optical performance while being downsized, with difficulties in optimizing lens configuration and movement conditions to minimize system size and maintain performance across the zoom range.
Innovation Solution
A zoom lens configuration with specific refractive powers and movement patterns, including a first lens unit with negative power, a second lens unit moving towards the object side, a third lens unit consisting of a single optical element, and a fourth lens unit with multiple lenses, where the intervals between lens units change during zooming, and the third lens unit moves along a convex locus to reduce variations in optical performance and incident angles of off-axial rays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a negative-lead type zoom lens configuration is used to downsize the system, then the overall lens size is reduced, but it becomes difficult to maintain high optical performance across the entire zoom range
Solution Approach 1:
The zoom lens is divided into four distinct lens units with alternating refractive powers (negative, positive, negative, positive), where each unit has specific movement characteristics during zooming. This segmentation allows independent optimization of each unit's function while maintaining compact overall size, resolving the contradiction between downsizing and optical performance consistency.
Solution Approach 2:
The lens units are designed with dynamic movement characteristics during zooming, where the second lens unit moves toward the object side, the third lens unit moves along a convex locus, and intervals between adjacent lens units change systematically. This dynamic configuration enables the lens to maintain high optical performance across the entire zoom range while keeping the overall system compact.
2Adaptability or versatility
If lens units are configured to move during zooming to achieve high zoom ratio and wide angle of view, then optical performance is improved, but the complexity of lens configuration and movement control increases
Solution Approach 1:
The zoom lens is divided into four distinct lens units with alternating refractive powers (negative, positive, negative, positive), where each unit has specific movement characteristics during zooming. This segmentation allows independent optimization of each unit's function while maintaining compact overall size, resolving the contradiction between downsizing and optical performance consistency.
Solution Approach 2:
The lens units are designed with dynamic movement characteristics during zooming, where the second lens unit moves toward the object side, the third lens unit moves along a convex locus, and intervals between adjacent lens units change systematically. This dynamic configuration enables the lens to maintain high optical performance across the entire zoom range while keeping the overall system compact.
3Ease of manufacture
If the third lens unit consists of a single optical element and the fourth lens unit includes multiple lenses at intervals, then manufacturing is simplified and size is reduced, but optical performance optimization becomes more challenging
Solution Approach 1:
Different lens units are designed with different structural characteristics tailored to their specific functions: the third lens unit uses a single optical element optimized for its specific role in the optical path, while the fourth lens unit employs multiple lenses arranged at intervals to achieve its specific optical function. This localized optimization allows each unit to be manufactured with appropriate complexity for its function while contributing to overall 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 a zoom lens with a high zoom ratio and wide angle of view, maintaining high optical performance across the zoom range while effectively downsizing the system, by optimizing lens unit movements and refractive powers, thus addressing the limitations of existing technologies.
Implementation Method 1
a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, and a fourth lens unit having a positive refractive power
Data Source
AI summary
A zoom lens includes, in order from object side, a negative first unit, a positive second unit, a negative third unit, and a positive fourth unit, wherein, for zooming to telephoto end, the second unit moves toward object side, the third unit moves and an interval between each pair of adjacent units is changed, wherein, at telephoto end as compared to wide angle end, the interval between the first and second units is smaller, the interval between the second and third units is larger, the interval between the third and fourth units is larger, and the fourth unit is positioned closer to image side, wherein the third unit consists of a single optical element, wherein the fourth unit includes plural lenses arranged at intervals, and wherein focal lengths of the third and fourth units and the interval between the third and fourth units at telephoto end are appropriately set.