Zoom Lens First Unit Segmentation for Weight Reduction
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Solution Overview
Problem
Existing zoom lenses with high zoom ratios face challenges in achieving a small and lightweight design while maintaining high optical quality across the entire zoom range, often resulting in increased size and weight due to the large first lens unit and significant aberrations at the telephoto end.
Innovation Solution
A zoom lens configuration comprising a first positive lens unit and a meniscus negative lens unit, with specific refractive power arrangements and interval changes between lens units during zooming, to minimize the size and weight of the first lens unit and correct aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the first lens unit is made large to achieve high zoom ratio, then the zoom ratio is improved, but the size and weight of the lens increase
Solution Approach 1:
The first lens unit is divided into two separate lenses: a positive lens and a negative lens. This segmentation allows for more flexible optical design that achieves high zoom ratio without requiring a single large lens unit, thereby reducing overall weight while maintaining adaptability.
Solution Approach 2:
The patent changes the refractive power parameters of the first lens unit by using a positive lens with specific refractive power range (-5.0 < f11/fw < -2.0) combined with a negative lens. This parameter optimization enables high zoom ratio achievement without increasing the physical size or weight of the lens unit.
2Adaptability or versatility
If the first lens unit is made large to achieve high zoom ratio, then the zoom ratio is improved, but the size of the lens increases
Solution Approach 1:
By segmenting the first lens unit into separate positive and negative lenses, the patent achieves compact arrangement that reduces the overall length of the lens unit while maintaining the optical capabilities needed for high zoom ratio.
Solution Approach 2:
The patent optimizes the focal length parameters and refractive power distribution between the two lenses to achieve high zoom ratio within a compact length constraint, avoiding the need for a single large lens unit.
3Adaptability or versatility
If the first lens unit is made large for high zoom ratio, then the zoom ratio is improved, but optical characteristics deteriorate due to aberrations
Solution Approach 1:
The first lens unit is segmented into a positive lens and a negative lens working together. This segmentation enables better control over optical paths and aberration correction, maintaining high optical characteristics across the entire zoom range including telephoto side where aberrations would otherwise be significant.
Solution Approach 2:
The patent carefully controls the refractive power parameters of both lenses (positive lens: -5.0 < f11/fw < -2.0, negative lens: -0.5 < f12/fw < 2.0) to optimize optical characteristics while achieving high zoom ratio, preventing aberration generation.
4Device complexity
If a single lens structure is used for the first lens unit, then the structure is simple, but optical characteristics and aberration correction are insufficient
Solution Approach 1:
The first lens unit is divided into two lenses with different refractive powers. This segmentation provides sufficient degrees of freedom for aberration correction while maintaining relatively simple structure, achieving high optical characteristics without excessive complexity.
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 compact, lightweight zoom lens with improved optical characteristics across the entire zoom range by effectively managing aberrations and reducing the size of the first lens unit, thereby achieving a high zoom ratio with satisfactory optical performance.
Implementation Method 1
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; a fourth lens unit having a positive refractive power; a fifth lens unit having a negative refractive power; and a sixth lens unit having a positive refractive power
Data Source
AI summary
Provided is a zoom lens, including, in order from an object side to an image side: 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; a fourth lens unit having a positive refractive power; a fifth lens unit having a negative refractive power; and a sixth lens unit having a positive refractive power, in which an interval between the first lens unit and the second lens unit is increased during zooming from a wide angle end to a telephoto end, an interval between adjacent lens units is changed during zooming, and the lens shapes of lenses included in the first lens unit are appropriately set.