Patent ID: 6794794
Filing Date: 2004-09-21
Classification: G02B

Abstract:
A scanning apparatus comprising:a light source for providing a beam of light; a reflector disposed in the path of the beam of light to produce a reflected beam of light; a mount for supporting the reflector, the mount including a torsion spring mechanism for holding the reflector for oscillation on the torsion spring mechanism, the reflector and the torsion spring mechanism having a resonant frequency of oscillation; an oscillator for oscillating the reflector on the torsion spring mechanism at a frequency close to or at the resonant frequency of the reflector; the oscillation of the reflector producing a scanning reflected light beam scanning along a scan path; at least one sensor disposed in the scan path of the scanning reflected light beam for producing a sensor signal when the scanning reflected light beam illuminates the sensor; and a control and drive system for receiving the sensor signal and thereby monitoring the oscillation of the reflector, for producing a drive signal based on the oscillation of the reflector, said drive signal having a drive amplitude, a drive frequency close to or at the resonant frequency, and a drive offset, the drive signal being provided to the oscillator to drive the oscillator causing mechanical oscillation at the drive frequency and at a desired mechanical amplitude and offset.