Wide-Angle Zoom Lens Layout With Split Stabilization Subunit
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Solution Overview
Problem
Existing wide-angle zoom lenses with image stabilization face challenges in achieving both compact size and high optical performance due to the increased size of actuators required for multiple moving lens units, particularly when the entire second lens unit serves as an image stabilization unit.
Innovation Solution
A zoom lens configuration with a first lens unit that does not move during zooming, a second lens unit that moves for image stabilization, and a rear lens group that includes a focus lens unit, where the second lens unit is divided into subunits with specific refractive power distributions and movements, and the rear lens group includes aspherical lenses to maintain compactness and high optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple lenses are moved for image stabilization, then image stabilization performance is improved, but the actuator size increases and the overall lens size cannot be downsized
Solution Approach 1:
The second lens unit is divided into two subunits (L2a and L2b), where only the subunit L2a with positive refractive power serves as the image stabilization unit. This segmentation allows image stabilization to be achieved with a smaller subset of lenses rather than moving the entire second lens unit, thereby reducing actuator size while maintaining stabilization performance.
Solution Approach 2:
The patent applies local quality by assigning different functions to different parts of the second lens unit. Specifically, subunit L2a is designated for image stabilization with specific curvature radius constraints (0.3 < (R1+R2)/(R1-R2)(-f1)/f2 < 0.7), while subunit L2b handles other optical functions. This localized functional assignment enables compact actuator design focused only on the essential stabilization component.
2Reliability
If the second lens unit is used entirely for image stabilization, then image stabilization is achieved, but the zoom lens cannot be downsized
Solution Approach 1:
By segmenting the second lens unit into L2a and L2b, the patent enables image stabilization to be performed by only subunit L2a. This reduces the moving mass and dimensional requirements compared to using the entire second lens unit, allowing for a more compact overall zoom lens design while preserving the image stabilization function.
Solution Approach 2:
The patent applies partial action by using only a portion (subunit L2a) of the second lens unit for image stabilization rather than the entire unit. This partial utilization of optical components achieves the necessary stabilization effect with reduced mechanical movement requirements, enabling lens downsizing.
3Volume of moving object
If lens units are optimized for compact size, then zoom lens downsizing is achieved, but optical performance and aberration control may deteriorate
Solution Approach 1:
The patent employs parameter changes by imposing specific constraints on the curvature radii of subunit L2a through the inequality 0.3 < (R1+R2)/(R1-R2)(-f1)/f2 < 0.7. This parameter optimization ensures that even with the reduced size of the image stabilization unit, the optical performance and aberration control are maintained at high levels, resolving the trade-off between compactness and optical quality.
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 small-sized zoom lens with a wide angle of view and high optical performance by minimizing the number of moving lens units and optimizing their movements, reducing the size and weight of the actuator, and effectively correcting aberrations.
Implementation Method 1
a first lens unit L1 having a negative refractive power, a second lens unit L2 having a positive refractive power, and a rear lens group including one or more lens units
Data Source
AI summary
A zoom lens includes a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a rear lens group including one or more lens units, which are disposed in this order from an object side to an image side, wherein a distance between adjacent lens units changes in zooming, wherein the first lens unit does not move and the second lens unit moves in zooming, wherein the second lens unit includes subunits L2a and L2b having a positive refractive power, which are disposed in this order from the object side, wherein the subunit L2a moves to include a component in a direction perpendicular to an optical axis in image stabilization, wherein the rear lens group includes a focus lens unit that moves in focusing, and wherein the zoom lens satisfies predetermined inequalities.