Apple Inc.
Resonant scanning mirror with both magnetic and mechanical torsion springs

Abstract:

Optical apparatus includes a shaft, which is configured to rotate about an axis of the shaft relative to a base. A mirror is fixed to the shaft so that the mirror rotates about the axis. A rotor including a permanent magnet is fixed to rotate with the shaft. A stator is configured to generate a magnetic field having a DC component in a vicinity of the rotor. A torsion spring, extending along the axis, has a first end that is attached to rotate with the shaft and a second end attached to the base.