Zoom Lens Fourth Unit Perpendicular Shift Image Stabilization
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Solution Overview
Problem
Existing zoom lenses face challenges in maintaining high optical performance while reducing size and weight, particularly at the telephoto end, due to limitations in image stabilization which often result in eccentric aberrations and increased size from the need for large torque for driving the compensation lens unit.
Innovation Solution
A zoom lens configuration with a specific arrangement of lens units, including a fourth lens unit that moves perpendicular to the optical axis for image stabilization, and conditional expressions to optimize the refractive powers and focal lengths of these units, allowing for effective image blur correction without significant size or weight increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the moving distance of the compensation lens unit is increased to increase the image stabilizing correction angle at the telephoto end, then the image blur correction capability is improved, but significant eccentric aberrations occur causing degradation of image quality
Solution Approach 1:
The compensation lens unit is divided into multiple lens elements (including a negative lens and a positive lens) that can move independently or in coordinated fashion. This segmentation allows the system to achieve the required image blur correction angle while distributing the optical correction across multiple elements, thereby reducing individual element displacement and minimizing eccentric aberrations.
Solution Approach 2:
The patent optimizes specific parameters of the compensation lens unit including the focal length ratio between the negative and positive lenses, the distance from the compensation lens unit to the image plane, and the movement characteristics. By carefully controlling these parameters, the system achieves effective image stabilization while maintaining high optical performance even at large correction angles.
2Manufacturing precision
If the number of lenses in the compensation lens unit is increased to decrease eccentric aberrations, then the image quality is improved, but the weight increases requiring larger driving torque and increasing the overall system size
Solution Approach 1:
Instead of uniformly increasing the number of lenses throughout the compensation unit, the patent applies quality enhancement locally by optimizing the specific lens elements that have the greatest impact on reducing eccentric aberrations. The configuration includes a negative lens and a positive lens with specifically optimized focal lengths and positions, providing effective aberration correction without unnecessary weight addition.
Solution Approach 2:
The compensation lens unit employs composite optical design combining different lens materials and structures (negative and positive lenses with specific refractive properties) to achieve superior optical performance. This composite approach allows effective correction of eccentric aberrations while maintaining a compact and lightweight structure compared to using a single large lens or multiple identical lenses.
3Volume of moving object
If the size of the zoom lens system is reduced to make it compact, then the portability is improved, but the optical performance during image stabilization deteriorates
Solution Approach 1:
The compensation lens unit is integrated within the existing zoom lens structure in a nested configuration, where the compensation lenses are positioned within the space already defined by the other lens units. This nesting approach allows the image stabilization function to be added without significantly increasing the overall system size, while the optimized design ensures high optical performance is maintained.
Solution Approach 2:
The patent employs a dynamic image stabilization mechanism where the compensation lens unit moves perpendicular to the optical axis in response to detected image blur. The movement distance and speed are dynamically adjusted based on the magnitude of the blur correction needed, allowing effective stabilization performance in a compact design that doesn't require oversized mechanical components.
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
Enables easy image blur correction with a compact and lightweight compensation lens unit, effectively correcting large image blur angles at the telephoto end while maintaining high optical performance and reducing the overall size of the lens system.
Implementation Method 1
the fourth lens unit includes a positive lens and a negative lens and is configured to move in a direction having a component perpendicular to the optical axis so as to move an imaging position in the direction perpendicular to the optical axis
Implementation Method 2
a first lens unit having positive refractive power; a second lens unit having negative refractive power; a third lens unit having positive refractive power; a fourth lens unit having negative refractive power; and a fifth lens unit having positive refractive power
Data Source
AI summary
A zoom lens includes first to fifth lens units having positive, negative, positive, negative, and positive refractive powers. During zooming, the fourth lens unit having a positive lens and a negative lens does not move, and the second, third, and fifth lens units move. The fourth lens unit moves to have a component perpendicular to the optical axis. The focal length of the entire system at the telephoto end, the focal length of the fourth lens unit, the focal length and the material of the positive lens of the fourth lens unit, the maximum moving distance, at the telephoto end, of the fourth lens unit, the lateral magnification of the fourth lens unit at the telephoto end, and the lateral magnification, at the telephoto end, of a lens system disposed at the image plane side with respect to the fourth lens unit are appropriately set.