Lens Barrel Yoke Layout for Stable Voice Coil Lens Motion
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Solution Overview
Problem
Existing lens barrels employing voice coil motors face challenges in achieving improved driving force and stability due to non-optimal arrangement of yokes and magnets, leading to uneven magnetic fields and potential collisions during lens movement.
Innovation Solution
The lens barrel design includes a first and second yoke with a center yoke disposed between them, where the first and second side yokes are arranged non-parallel to each other, with magnets positioned to create a uniform magnetic field distribution, allowing for efficient and stable lens movement by a voice coil motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the yokes and magnets are arranged in a conventional parallel configuration, then the structure is simple and easy to manufacture, but the magnetic field distribution becomes uneven and the driving force is insufficient
Solution Approach 1:
The patent applies asymmetry by arranging the first and second side yokes non-parallel to each other, forming an angled configuration rather than a conventional parallel arrangement. This asymmetric positioning of the yokes and magnets creates a more uniform magnetic field distribution across the coil, thereby enhancing the driving force of the voice coil motor while accepting increased structural complexity
2Force
If the yokes are arranged to improve magnetic field uniformity, then the driving force increases, but the lens movement stability decreases due to potential collisions
Solution Approach 1:
The patent applies local quality by positioning the first and second side yokes at different angles and locations relative to the central yoke and magnets. This localized variation in yoke positioning optimizes the magnetic field distribution in different regions, improving overall driving force while the careful design ensures that the lens movement path remains clear of obstructions, maintaining stability
3Speed
If the voice coil motor is designed with higher driving force, then the lens movement speed increases, but the impact sounds increase due to unstable movement
Solution Approach 1:
The asymmetric arrangement of side yokes improves magnetic field uniformity, which enables smoother lens movement at higher speeds by reducing magnetic field fluctuations. This smoother operation minimizes vibrations and impact sounds that would otherwise occur during high-speed lens movement, allowing the system to achieve faster speeds without generating harmful impact noises
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 enhances the driving force and stability of the voice coil motor, ensuring stable lens movement and reduced impact sounds, while allowing for a more compact design within the lens barrel.
Implementation Method 1
a coil that is penetrated by the third yoke and is movable in the optical axis direction by magnetic forces of the first magnet and the second magnet
Data Source
AI summary
A lens barrel includes first and second yokes each having a length in an optical axis direction, a third yoke that has a length in the optical axis direction and is disposed between the first and second yokes, first and second magnets disposed on the first and second yokes, respectively, a coil that is penetrated by the third yoke and is movable in the optical axis direction by magnetic forces of the first and second magnets, and a lens holding frame that holds a lens and is movable together with the coil in the optical axis direction, wherein a first plane including a first side surface, which is farther from the third yoke, of the first yoke intersects with a second plane including a second side surface, which is farther from the third yoke, of the second yoke.