Imaging Lens Vibration Reduction via Third Lens Group Shift
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Solution Overview
Problem
Compact cameras face challenges in reducing size while maintaining high-quality imaging and effective vibration reduction, as existing lens systems struggle to efficiently integrate vibration reduction mechanisms without increasing weight or compromising optical performance.
Innovation Solution
The proposed imaging lens configuration includes a first lens group with positive refractive power, a stop, a second lens group with positive refractive power, and a third lens group with negative refractive power, where the second lens group moves along the optical axis during focusing and the third lens group remains stationary, allowing for vibration reduction by moving only the third lens group in a direction intersecting the optical axis, thus avoiding the need to move the aperture stop during vibration reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the lens group including the lens closest to the object side is moved during both focusing and vibration reduction, then both functions can be achieved, but it becomes difficult to control the tilt of the lens group within the allowable error range
Solution Approach 1:
The patent divides the lens system into multiple independent lens groups (first, second, and third lens groups) with different functions. The second lens group is dedicated to focusing operations, while the third lens group is dedicated to vibration reduction. This segmentation allows each group to be controlled independently, preventing tilt control issues that would arise from moving a single lens group for both functions.
2Adaptability or versatility
If a lens group including the aperture stop is moved during vibration reduction, then vibration reduction function is achieved, but the weight increases making it difficult to reduce apparatus size
Solution Approach 1:
The patent extracts the aperture stop from the vibration reduction lens group, placing it in a fixed position between the first and second lens groups. Only the third lens group (without the stop) is moved for vibration reduction, significantly reducing the weight of the moving component while maintaining the vibration reduction function.
3Adaptability or versatility
If the third lens group remains stationary during focusing, then vibration reduction by moving the third lens group becomes possible, but the focusing mechanism becomes more complex
Solution Approach 1:
The patent segments the focusing and vibration reduction functions into different lens groups. The second lens group handles focusing by moving along the optical axis, while the third lens group remains stationary during focusing and is dedicated to vibration reduction. This functional segmentation simplifies the overall control logic despite having multiple moving 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
This configuration achieves a reduction in apparatus size while maintaining high-precision vibration reduction and good optical performance, minimizing weight and aberration fluctuations, and allowing for effective correction of various aberrations.
Implementation Method 1
a second lens group G2 having a positive refractive power... the second lens group moves along an optical axis, and the third lens group remains stationary with respect to an image plane, during focusing from an object at infinity to a closest object
Implementation Method 2
image blur correction is performed by moving only the entire third lens group G3 or only a part of the third lens group G3 as a vibration reduction lens group in a direction intersecting the optical axis
Data Source
AI summary
The imaging lens consists of, in order from an object side, a first lens group, a stop, a positive second lens group, and a negative third lens group. The second lens group includes a negative lens and a positive lens. During focusing, the second lens group moves, and the third lens group does not move. Image blur correction is performed by moving the entire third lens group or a part of the third lens group in the direction intersecting the optical axis.