Optical Resonance Scanner Stationary Magnetic Driver
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Solution Overview
Problem
Conventional optical resonance scanners with magnetic drivers face limitations such as high inertia torque, wobbling motion due to transverse and vertical forces, and non-constant oscillation amplitudes across temperature variations, restricting operation above 16 kHz and with large mirrors.
Innovation Solution
The scanner employs a torsional resonance oscillator design with stationary coils and magnets, featuring a symmetrical magnetic flux arrangement and additional drive coils to minimize eddy currents and enhance driver efficiency, allowing operation at higher frequencies with constant oscillation amplitudes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If moving magnets or plungers are used in the electromagnetic driver, then the driving force is sufficient, but the bending element experiences high inertia torque and cannot operate above 16 kHz
Solution Approach 1:
The patent replaces the mechanical driver system (moving magnets or plungers) with a magnetic field-based driver system. The electromagnetic driver uses stationary magnets and coils to generate oscillating magnetic forces on the bending element without mechanical contact, eliminating the inertia torque that limited frequency to below 16 kHz and enabling operation above 16 kHz
Solution Approach 2:
The invention extracts and removes the moving parts (magnets or plungers) from the electromagnetic driver system, retaining only the stationary components (coils and magnets). This extraction eliminates the source of inertia torque while preserving the driving function through magnetic field interaction
2Force
If permanent magnets are arranged to generate flux through the bending element, then driving force is achieved, but transverse and vertical forces cause wobbling motion and imaging errors
Solution Approach 1:
The patent introduces asymmetry in the magnetic circuit design by positioning the permanent magnet offset from the center of the bending element. This asymmetric arrangement creates a preferred oscillation plane and stabilizes the oscillation by preventing wobbling motion, while the magnetic flux still effectively drives the bending element
Solution Approach 2:
The invention uses a magnetic circuit configuration where flux paths are carefully designed to replicate symmetric force distribution in the oscillation plane while eliminating out-of-plane forces. The magnetic circuit copies the beneficial driving force while filtering out the harmful transverse and vertical components that cause wobbling
3Reliability
If the magnetic flux path is long, then the magnetic circuit is complete, but eddy currents increase and driver efficiency decreases
Solution Approach 1:
The patent segments the magnetic flux path into distinct regions: a short air gap region for force generation and a longer return path through the bending element. The bending element itself is segmented with slots or air gaps that interrupt eddy current paths while maintaining magnetic flux continuity, reducing eddy current losses while preserving the complete magnetic circuit
Solution Approach 2:
The invention introduces the bending element as an intermediary magnetic component with specific geometric features (slots, air gaps, or laminated structure) that mediate between the need for a complete magnetic flux path and the need to minimize eddy currents. These features allow flux to pass while blocking eddy current circulation
4Area of moving object
If large mirrors with large diameter and thickness are used, then the scanning device can handle high power applications, but the oscillation frequency cannot exceed 16 kHz
Solution Approach 1:
The patent replaces the mechanical driver system with a magnetic field-based driver that can generate sufficient force on large, thick mirrors without the inertia limitations. This substitution enables large mirrors (with large diameter and thickness for high power applications) to oscillate at frequencies above 16 kHz by eliminating the mechanical coupling that caused high inertia torque
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 design significantly reduces eddy currents, increases driver efficiency, and maintains constant oscillation amplitudes across temperature variations, enabling operation above 16 kHz with large mirrors and scan angles.
Implementation Method 1
at least one stationary drive coil, wherein the drive coil is wound around a pole shoe, which is magnetically coupled to a magnet
Implementation Method 2
as the magnet-induced and coil-induced magnetic fluxes are superimposed, a first magnetic circuit is formed through the magnet and a first half of the pole shoe
Implementation Method 3
a spring-elastic bending element, which can be excited to effect oscillations, more particularly to effect rotational oscillations
Implementation Method 4
significantly reduces eddy currents, increases driver efficiency
Data Source
AI summary
An optical resonance scanner has a spring-elastic bending element (10) excitable to effect rotational oscillations about a longitudinal axis (A-A) using a stationary magnet (9) and a stationary drive coil (5) that is wound around a pole shoe (20). The pole shoe (20) is magnetically coupled to the magnet (9) and has two mutually opposite free ends (21, 22) between which the bending element (10) is arranged symmetrically so that a magnetic flux can be transferred substantially perpendicularly to the longitudinal axis (A-A). In superimposition of the magnet- and coil-induced magnetic fluxes the magnet (9) and a first half (23) of the pole shoe (20) form a first magnetic circuit (30), and the magnet (9) and a second half (24) of the pole shoe (20) form a second magnetic circuit (31), which run in opposite senses with respect to one another in a plane perpendicularly to the longitudinal axis (A-A) through a magnetizable section (6) of the bending element (10).