Zoom Lens Aberration Control via Segmented Image Stabilization
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Solution Overview
Problem
Existing zoom lenses with wide angles of view face challenges in correcting aberrations, particularly decentering aberration, during image stabilization and focusing, leading to difficulties in achieving high optical performance across the entire zoom range and all object distances.
Innovation Solution
A zoom lens configuration with a first negative refractive power unit, a second positive refractive power unit, a third negative refractive power unit, and a fourth positive refractive power unit, where the third unit assists in focusing and the fourth unit, divided into multiple lenses, performs image stabilization by moving in a direction perpendicular to the optical axis, effectively reducing aberrations and maintaining high optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wide angle of view (about 100°) is achieved in a negative lead type zoom lens, then the lens can encompass a wider range in one image, but it becomes very difficult to correct various aberrations and generates large decentering aberration during image stabilization
Solution Approach 1:
The fourth lens unit is divided into a plurality of lenses, with specific lenses (positive and negative lenses) configured to move independently in a direction including a component perpendicular to the optical axis for image stabilization. This segmentation allows different lenses within the same unit to have different movement characteristics, enabling effective aberration correction while maintaining wide angle capability
Solution Approach 2:
Different lenses within the fourth lens unit are assigned different functions: some lenses move for image stabilization while others remain relatively fixed or move differently. This local differentiation of function within the lens unit allows optimized performance for both wide angle viewing and aberration control during stabilization
2Reliability
If the entire third lens unit is configured to move perpendicular to the optical axis for image stabilization, then image stabilization function is achieved, but large decentering aberration is generated
Solution Approach 1:
Instead of moving the entire third lens unit, only specific lenses within the fourth lens unit are configured to move for image stabilization. This segmented approach allows the stabilization function to be achieved while minimizing the generation of decentering aberration by limiting the movement to only necessary components
Solution Approach 2:
The patent inverts the conventional approach by performing image stabilization using lenses within the fourth lens unit rather than the third lens unit. This inversion allows for more effective aberration control while achieving the same image stabilization objective
3Manufacturing precision
If lens units are moved for focusing and image stabilization, then high optical performance is achieved, but variations in aberration occur during focusing
Solution Approach 1:
The lens configuration employs dynamic movement of specific lenses within the fourth lens unit for both focusing and image stabilization. By making certain lenses movable while keeping others relatively fixed, the system can adaptively correct aberrations during focusing operations, minimizing variation and maintaining high optical performance across different object distances
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 minimizes variations in aberrations across different object distances and enables effective image stabilization, ensuring high optical performance and small decentering aberration, even at wide angles, by optimizing the movement and refractive power distribution of lens units.
Implementation Method 1
at least a part of the fourth lens unit is a lens system IS, which is configured to move in a direction including a component of a direction perpendicular to an optical axis for image stabilization
Implementation Method 2
at least the third lens unit is configured to move for focusing
Implementation Method 3
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
Provided is a zoom lens including, in order from an object side to an image side: 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; a fourth lens unit having a positive refractive power; and a rear lens group including at least one lens unit, the first lens unit, the second lens unit, the third lens unit, the fourth lens unit, and the rear lens group having an interval between each pair of adjacent lens units changed for zooming. The third lens unit is configured to move for focusing, and at least a part of the fourth lens unit forms a lens system IS, which is configured to move in a direction including a component of a direction perpendicular to an optical axis for image stabilization.