Zoom Lens Image Stabilization via Segmented Second Unit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing zoom lenses face challenges in minimizing image blur caused by shaking, particularly in reducing decentering aberrations and achieving a high decentering sensitivity while maintaining a compact and lightweight design for image stabilization, which affects the optical quality and size of the imaging system.
Innovation Solution
A zoom lens design featuring a refractive power arrangement with a first lens unit having a positive refractive power, a second lens unit with negative power acting as the image stabilizing unit, and a third lens unit with positive power, where the intervals between these units change during zooming, allowing the second lens unit to move perpendicular to the optical axis for image stabilization, thereby correcting image blur and maintaining optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the image stabilizing lens unit is decentered to correct image blur, then the blur correction amount increases, but decentering aberrations (coma, astigmatism, chromatic aberration, field curvature) increase causing image quality deterioration
Solution Approach 1:
The second lens unit is divided into multiple lens groups (negative lens group, positive lens group, and additional negative lens group). This segmentation allows each group to contribute differently to the overall optical function, enabling better control of decentering aberrations while maintaining effective blur correction capability.
Solution Approach 2:
Different lens groups within the second lens unit have different refractive powers and positions assigned to them. The negative lens groups and positive lens group are strategically positioned to create local optical characteristics that collectively reduce decentering aberrations while maintaining the required image stabilization performance.
2Length of stationary object
If the decentering sensitivity is increased to reduce the movement amount of the image stabilizing lens unit, then the apparatus size can be reduced, but the decentering aberrations become more pronounced
Solution Approach 1:
By segmenting the second lens unit into multiple lens groups with different refractive powers, the patent achieves high decentering sensitivity with a compact structure. The segmented design allows the lens unit to be positioned closer to the image plane while maintaining effective blur correction, thereby reducing apparatus size without excessive decentering aberrations.
3Weight of moving object
If the image stabilizing lens unit is made smaller and lighter to downsize the apparatus, then the apparatus size and weight are reduced, but the blur correction capability may be compromised
Solution Approach 1:
The second lens unit is segmented into multiple lens groups that can be optimized individually for weight and performance. This allows the overall unit to be made smaller and lighter while maintaining the required blur correction capability through the coordinated action of the segmented lens groups.
Solution Approach 2:
The patent optimizes parameters such as refractive indices, curvature radii, and thicknesses of individual lens groups within the second lens unit. By carefully adjusting these parameters, the lens unit achieves maximum blur correction capability with minimized weight and size.
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 effectively reduces decentering aberrations, enhances decentering sensitivity, and achieves a compact, lightweight image stabilizing lens unit with improved optical performance, maintaining image quality across the zoom range while minimizing the size and weight of the apparatus.
Implementation Method 1
a second lens unit with negative power acting as the image stabilizing unit, and a third lens unit with positive power, where the intervals between these units change during zooming, allowing the second lens unit to move perpendicular to the optical axis for image stabilization
Implementation Method 2
a first lens unit having a positive refractive power, a second lens unit with negative power acting as the image stabilizing unit, and a third lens unit with positive power
Data Source
Figure 1
Figure 2A~2B
Figure 3
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; and a third lens unit having a positive refractive power, in which: an interval between the first lens unit and the second lens unit is increased, and an interval between the second lens unit and the third lens unit is decreased during zooming from a wide angle end to a telephoto end; one of a whole and a part of the second lens unit is an image stabilizing lens unit which moves to have a component in a direction perpendicular to an optical axis so as to move an imaging position in the direction perpendicular to the optical axis; and a focal length (fw) of an entire system at the wide angle end, a focal length (f1) of the first lens unit, and a movement amount (ΔL1) of the first lens unit during zooming from the wide angle end to the telephoto end are each set appropriately.