Patent ID: 8896899
Filing Date: 2014-11-25
Classification: G02B,H01S

Abstract:
1. A laser beam marker for projecting a circular or elliptical pattern onto a receiving surface comprising: a housing having a frontmost optical window; a laser beam generating device mounted in said housing; a mirror having a reflective front face, and a back face; an electric motor mounted in said housing, said motor including a rotatable shaft; said mirror having its back face attached to an end of said motor shaft, the front face of said mirror being receptive of a laser beam outputted from said laser beam generating device, whereby the angle of incidence between the first face of said mirror and the laser beam determines an elliptical or circular pattern of said laser beam reflected from said mirror through said optical window of said housing upon rotation of said mirror; a DC source of voltage mounted in said housing; a motor drive circuit mounted in said housing; a switch mounted in said housing, said switch being electrically connected between said voltage source, and said motor and laser beam generating device, said switch being selectively operable for simultaneously connecting said voltage source thereto, or disconnecting it therefrom; and said motor drive circuit being responsive to the operation of said switch to connect said voltage source thereto, for initially applying a constant level of DC voltage to said motor to overcome inertia for rotating said motor shaft for a first period of time followed by applying a pulsed DC voltage to said motor for a second period of time to reduce the duty cycle of said motor, until operation of said switch to turn off said device by disconnecting said voltage source from said motor and laser beam generating device.