Circular Mirror Drive Coil for Efficient Lorentz Force Generation
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Solution Overview
Problem
Conventional mirror drive devices face challenges in achieving efficient driving force due to their rectangular shape, which results in high moment of inertia and inefficient interaction between the electromagnetic coil and the magnetic field, leading to suboptimal Lorentz force generation.
Innovation Solution
A mirror drive device with a circularly shaped movable portion and a 2n-sided polygon-shaped drive coil, where n is a finite integer of three or more, is designed. The drive coil is arranged below the mirror and inside it when viewed orthogonally, ensuring at least one side is orthogonal to the magnetic field, optimizing the Lorentz force generation. Additionally, the magnetic field is angled to intersect with the electric current direction, enhancing driving force efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the mirror portion is made rectangular to match conventional designs, then the structure is simple and easy to manufacture, but the moment of inertia increases due to wasted corner regions not irradiated by the laser beam
Solution Approach 1:
The mirror portion is designed with a circular shape instead of a rectangular shape. This curvature eliminates the corner regions that would not be irradiated by the laser beam, thereby reducing the mass and moment of inertia of the moving object while maintaining ease of manufacture through standard circular fabrication processes
2Device complexity
If the coil is formed along the shape of the mirror portion, then the structure is compact and integrated, but the sides cannot be orthogonal to the magnetic field, resulting in inefficient driving force generation
Solution Approach 1:
The coil is designed with a circular shape that allows its sides to be orthogonal to the magnetic field lines. This circular configuration, combined with the circular mirror portion, maintains structural integration and compactness while enabling efficient Lorentz force generation through proper orientation with the magnetic field
Solution Approach 2:
The magnetic field is oriented at a specific angle (45 degrees) relative to the swing axis, which optimizes the interaction between the circular coil and the magnetic field. This parameter change in field orientation ensures that the coil sides can be orthogonal to the magnetic field direction, maximizing the driving force efficiency
3Weight of moving object
If the movable portion is made circular to reduce moment of inertia, then the driving force efficiency improves, but the manufacturing precision requirements increase for maintaining circular geometry and coil orientation
Solution Approach 1:
The circular shape of the movable portion and coil is designed with standard geometric parameters that can be manufactured using conventional precision machining and fabrication techniques. The circular geometry provides natural symmetry that simplifies alignment and orientation requirements during manufacturing and assembly
4Speed
If the drive coil is positioned inside the mirror when viewed orthogonally, then the air resistance and moment of inertia are reduced, but the space for coil windings is limited
Solution Approach 1:
The drive coil is positioned in the plane of the mirror (when viewed orthogonally) rather than being stacked above or below it. This planar arrangement utilizes the two-dimensional space efficiently, allowing sufficient coil winding space while maintaining a compact profile that minimizes air resistance and moment of inertia, thereby improving response speed
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 air resistance and moment of inertia, allowing for more efficient driving force generation, as demonstrated by increased optical deflection angles and reduced air resistance compared to conventional designs.
Implementation Method 1
the direction of the magnetic field orthogonal to a direction of an electric current flowing through the drive coil, so that the Lorentz force can be effectively generated
Data Source
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AI summary
A mirror drive device is provided as one capable of efficiently gaining a driving force. The mirror drive device 1 has a fixed frame 5; a movable portion 7 supported so as to be swingable relative to the fixed frame 5, through torsion bars 10a, 10b extending on an identical straight line, and being of a circular shape; a mirror 9 arranged on a principal surface 7a of the movable portion 7; and a permanent magnet 3 forming a magnetic field around the movable portion 7; the movable portion 7 has a drive coil 12 arranged below the mirror 9; the drive coil 12 is of a 2n-sided polygon shape (where n is an integer of 3 or more) when viewed from a direction orthogonal to the principal surface 7a, at least one side of which is orthogonal to a direction of the magnetic field F.