Patent ID: 7367510
Filing Date: 2008-05-06
Classification: G06K

Abstract:
1. An arrangement for controlling laser beam intensity, comprising: a screen; a projector for projecting an image on the screen, including a laser for emitting a laser beam of an intensity, a scanner for sweeping the laser beam in mutually orthogonal directions in a pattern of scan lines each having a number of pixels, and a controller for illuminating selected pixels with the laser beam to form the image on the screen; a detector for sensing the intensity of the laser beam during a calibration mode and during a projection mode, and for generating a control signal when the intensity has changed from a reference intensity during the projection mode; and the controller being further operative for storing the intensity of the laser beam reflected from the screen as the reference intensity during the calibration mode, and for changing the intensity of the laser beam by reducing electrical power to the laser when the control signal is generated during the projection mode.