Zoom Lens Design for Compact High-Ratio Imaging
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Solution Overview
Problem
Conventional zoom lenses with high zoom ratios tend to be large and heavy, leading to image blur issues due to camera shake, and achieving high optical performance across the zoom range while downsizing the system is challenging.
Innovation Solution
A zoom lens configuration comprising a first lens unit with positive refractive power, a second lens unit with negative refractive power, and a rear unit with multiple positive refractive power lens units, where the second lens unit moves towards the object side and intervals between lens units are adjusted during zooming, satisfying specific conditional expressions to optimize focal lengths and movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a zoom lens with high zoom ratio is designed, then the magnification-varying ratio is improved, but the total length and weight of the zoom lens increase
Solution Approach 1:
The zoom lens is divided into multiple lens units (first lens unit with positive refractive power, second lens unit with negative refractive power, and subsequent lens units) that can move independently relative to each other. This segmentation allows each unit to contribute differently to the zoom function, enabling high zoom ratio while controlling overall size and weight.
Solution Approach 2:
The zoom lens employs dynamic movement of lens units during zooming operation. The first lens unit moves toward the object side, the second lens unit moves toward the image side, and intervals between lens units are changed. This dynamic configuration enables the lens to achieve high magnification-varying ratio while maintaining a compact form factor.
2Reliability
If the zoom lens size and weight are increased, then the optical performance can be improved, but the image stabilizing capability deteriorates due to camera shake and vibration
Solution Approach 1:
The invention optimizes specific parameter ranges including the focal length of the first lens unit (f1), focal length of the second lens unit (f2), and the distance from the rear lens surface to the image plane (dLP). By constraining these parameters within specific ranges, the lens achieves high optical performance while maintaining a compact size that reduces susceptibility to vibration-induced image blur.
3Length of moving object
If the entire system of the zoom lens is downsized, then the compactness is improved, but it becomes difficult to obtain high optical performance over the entire zoom range
Solution Approach 1:
Different lens units are assigned specific functions and optical characteristics. The first lens unit (positive refractive power) and second lens unit (negative refractive power) have different movement patterns and focal length characteristics. This local differentiation of optical quality and function allows the compact system to maintain high optical performance across the entire zoom range by optimizing each unit's contribution.
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 compact, lightweight zoom lens with improved optical performance across the zoom range, effectively reducing image blur and maintaining high optical quality while allowing for image stabilization.
Implementation Method 1
a first lens unit having a positive refractive power, a second lens unit having a negative refractive power... in order to obtain high optical performance over the entire zoom range at a high zoom ratio while downsizing the entire system of the zoom lens, it is important to appropriately set, for example, a refractive power and a lens configuration of each of the first lens unit and the second lens unit
Data Source
AI summary
The zoom lens according to the present invention consists of, in order from an object side to an image side, a positive first lens unit, a negative second lens unit, and a positive rear unit including at least four lens units. The second lens unit moves toward the object side during zooming from a wide angle end to a telephoto end, and an interval between each pair of adjacent lens units is changed during zooming. The rear unit includes a positive lens unit LP, which is arranged closest to the image side. Focal lengths of the zoom lens at the wide angle end and at the telephoto end, focal lengths of the first lens unit and the second lens unit, and a distance from the lens surface of the lens unit LP on the image side to an image plane at the telephoto end are each set appropriately.