Optical Unit Magnetic Spring for Shake Correction
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Solution Overview
Problem
Optical units with shake correction functions face issues due to magnetic spring size and optical axis deviation caused by unbalanced magnetic attraction forces, particularly when the magnetic member is not well-balanced with respect to the swing center of the movable body.
Innovation Solution
The optical unit design includes a magnetic spring with a home position returning magnet and an attracted member disposed on the optical axis, where the attracted member and home position returning magnet face each other in the optical axis direction, allowing for a reduced magnetic spring size and avoiding optical axis deviation, using a single-pole magnet for cost-effectiveness and optimizing the planar shape of the magnetic spring based on swing loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the magnetic member is disposed at only one position for reducing the size of the optical unit, then the size of the optical unit is reduced, but the movable body is attracted in a direction where the magnetic member is disposed and thus the optical axis of the optical element and the swing center of the movable body are deviated from each other
Solution Approach 1:
The magnetic spring is segmented into two separate components: a magnetic member disposed on the movable body and a magnet disposed on the fixed body. This segmentation allows the magnetic attraction force to be generated while maintaining proper balance and avoiding optical axis deviation, as the magnet on the fixed body can be positioned to provide balanced attraction without causing the movable body to shift laterally.
Solution Approach 2:
The magnet on the fixed body acts as an intermediary element that provides the magnetic attraction force to return the movable body to the home position. By placing the magnet on the fixed body rather than the movable body, the system achieves balanced magnetic spring characteristics while maintaining optical axis alignment, as the magnet serves as a stable reference point for the attraction force.
2Volume of moving object
If the magnetic member is not disposed in a well-balanced manner with respect to the swing center of the movable body, then the size of the optical unit can be reduced, but characteristics of the optical unit are deteriorated due to unbalanced magnetic attraction force
Solution Approach 1:
Dividing the magnetic spring into separate components on the movable body and fixed body allows for optimized positioning of each component. The magnetic member on the movable body can be positioned for compactness while the magnet on the fixed body is positioned to provide balanced attraction force, achieving both size reduction and reliable shake correction characteristics.
Solution Approach 2:
Different parts of the magnetic spring system have different functions: the magnetic member on the movable body provides compact integration while the magnet on the fixed body provides balanced attraction. This local differentiation of quality and function allows the system to achieve both compact size and reliable performance.
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 reduces the size and weight of the magnetic spring, prevents optical axis deviation, and allows for the use of an inexpensive magnet, enhancing the performance and cost-effectiveness of the optical unit's shake correction functionality.
Implementation Method 1
a magnetic attraction force acts between the attracted member and the home position returning magnet
Implementation Method 2
The magnetic drive mechanism includes a coil fixed to the movable body and a magnet which is fixed to the fixed body and faces the coil
Data Source
AI summary
An optical unit with a shake correction function includes a fixed body, a movable body having an optical element, a swing support mechanism swingably supporting the movable body, a magnetic drive mechanism structured to swing the movable body, and a magnetic spring structured to return the movable body to a home position where a predetermined axial line and an optical axis of the optical element are coincided with each other. The magnetic spring includes a home position returning magnet disposed in one of the movable body and the fixed body, and an attracted member disposed in the other of the movable body and the fixed body so that a magnetic attraction force acts between the attracted member and the home position returning magnet. The attracted member and the home position returning magnet are disposed on the optical axis and face each other in a direction of the optical axis.