Lens Driving Device with Isosceles Trapezoid Magnets for Shaking Correction
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Solution Overview
Problem
Existing lens driving devices with shaking correction functions face challenges in maintaining a compact size and high precision position detection without increasing the number of components, which leads to higher costs and reduced driving force during swinging.
Innovation Solution
The lens driving device incorporates isosceles trapezoid-shaped magnets at the corners of a square magnet support, eliminating the need for additional position detection magnets and using Hall elements mounted behind the magnets for precise detection, while maintaining the driving force through uncut correction coils and a swing supporting mechanism with linear spring members or rotating members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional position detection magnets are added to achieve high precision position detection, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The magnets (55A, 55B) serve dual functions: generating magnetic fields for driving the focus coil and correction coils, and simultaneously serving as position detection targets for Hall elements. This eliminates the need for separate position detection magnets, reducing component count while maintaining high position detection precision through the magnetic field interactions.
Solution Approach 2:
The patent combines the driving magnet function and position detection target function into a single integrated magnetic field system. The same magnets that generate driving force also enable position detection when used with Hall elements, merging two separate functional systems into one unified structure.
2Volume of moving object
If magnets are placed at corners of magnet support to reduce device size, then volume is reduced, but position detection precision may be compromised
Solution Approach 1:
The patent employs isosceles trapezoid-shaped magnets with asymmetric geometry, where the longer base faces the center of the magnet support and the shorter base faces outward. This asymmetric configuration optimizes both the magnetic field distribution for compact positioning and the position detection precision, allowing corner placement without sacrificing measurement accuracy.
3Device complexity
If correction coils are cut to accommodate magnet placement, then device complexity is reduced, but driving force is reduced
Solution Approach 1:
The patent resolves the spatial conflict between correction coils and magnets by changing the dimensional arrangement: correction coils are wound around axes parallel to the Z-axis (optical axis) and positioned at intervals along the Z-axis direction, rather than in the same radial plane as the magnets. This three-dimensional arrangement allows full-length coils to generate sufficient driving force while accommodating corner-placed magnets.
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 results in a compact, low-cost lens driving device with high precision position detection and stable swinging force, avoiding the complexity and cost increase associated with additional position detection magnets.
Implementation Method 1
When the focus coil 54A of the focusing unit 51 is electrified, Lorentz force in the Z-axis direction is generated, and the lens support 53 moves in the Z-axis direction based on the Lorentz force.
Implementation Method 2
when the P side correction coils 59AP of the hand shake correcting unit 52 are electrified, the P side correction coils 59AP generate the Lorentz force in the P-axis direction, and the magnets 55A generate counteracting force, so that the focusing unit 51 swings in the P-axis direction.
Implementation Method 3
Hall elements 61 for position detection
Data Source
AI summary
The present invention provides a lens driving device with a shaking correction function, which does not need magnets for position detection and also cannot reduce driving force during swinging. The lens driving device is configured as follows: a square frame shaped magnet support, each magnet is a cylinder in an isosceles trapezoid shape and is mounted in a corresponding corner in a manner that its long base faces the center of the magnet support, one or two X-direction magnetic force detection mechanisms have detection sensitivity for X-axis direction components of magnetic induction intensity and are mounted on the outer side of the corresponding magnets in a Y-axis direction, and one or two Y-direction magnetic force detection mechanisms have detection sensitivity for Y-axis direction components of magnetic induction intensity and are mounted on the outer side of the corresponding magnets in an X-axis direction.