Four-Unit Zoom Lens Layout for Compact Aberration Control
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving high optical performance while being compact and lightweight, with significant aberration fluctuations due to increased refractive powers in lens units, making it difficult to correct various aberrations with a small number of lenses.
Innovation Solution
A zoom lens configuration with a first positive lens unit, a fixed second negative lens unit, and moving third and fourth positive lens units, where distances between units change during zooming, including aspherical surfaces to suppress aberrations, and a focus lens unit with reduced weight and simplified mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the refractive power of each lens unit is increased to make the zoom lens compact, then the size of the zoom lens is reduced, but fluctuations of various aberrations become significant and it becomes difficult to correct aberrations
Solution Approach 1:
The zoom lens is divided into multiple lens units (first through fourth lens units) with different refractive powers. By segmenting the optical system and assigning specific functions to each unit (positive, negative, positive, positive arrangement), the patent achieves compact size while distributing aberration correction responsibilities across multiple specialized components rather than requiring excessive refractive power in single elements.
Solution Approach 2:
Each lens unit is designed with specific local optical properties - the first lens unit has positive refractive power for overall focusing, the second has negative power for zooming control, and the third and fourth have positive power with specific aberration correction functions. This local optimization of optical qualities allows compact design without sacrificing aberration correction performance.
2Device complexity
If a small number of lenses are used to reduce weight and complexity, then the zoom lens becomes lighter and simpler, but it becomes difficult to correct various aberrations associated with zooming
Solution Approach 1:
The patent divides the optical system into four functional lens units with a positive-negative-positive-positive power arrangement. This segmentation allows each unit to be optimized for specific functions (focusing, zooming, aberration correction) while maintaining a relatively small total lens count, achieving both simplicity and effective aberration control.
Solution Approach 2:
The lens units are designed to perform multiple functions simultaneously. For example, the first lens unit with positive refractive power contributes to overall focusing while also helping correct certain aberrations. The second lens unit with negative power enables zooming while participating in aberration balance. This multi-functionality reduces the need for additional dedicated correction lenses.
3Volume of moving object
If the distances between lens units are adjusted during zooming to achieve compact size, then the zoom lens becomes smaller, but the movement mechanisms become more complex
Solution Approach 1:
The patent employs dynamic adjustment of distances between lens units during zooming operations. The first lens unit moves to enable focusing, while distances between subsequent units are adjusted to achieve zooming functionality. This dynamic configuration allows the lens to maintain compact size across different focal lengths while using relatively simple movement mechanisms compared to fixed compact designs.
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 configuration achieves a compact, lightweight zoom lens with high optical performance across the entire zoom range, minimizing aberrations and enabling quick zooming and image stabilization.
Implementation Method 1
The first lens unit includes a positive lens and a negative lens... aspherical surfaces to suppress aberrations
Data Source
AI summary
A zoom lens includes, in order from an object side to an image side, a first lens unit with a positive refractive power, a second lens unit with a negative refractive power, a third lens unit with a positive refractive power, and a fourth lens unit with a positive refractive power. During zooming from a wide-angle end to a telephoto end, the first lens unit moves, the second lens unit is fixed, a distance between the first lens unit and the second lens unit is widened, a distance between the second lens unit and the third lens unit is narrowed, and a distance between the third lens unit and the fourth lens unit is narrowed. The first lens unit includes a positive lens and a negative lens. Each of the second, third, and fourth lens units consists of two lenses or less.