Monitoring light beam position in electro-optical readers and image projectors

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, and for generating a control signal when the intensity has changed from a reference intensity;
• and
• the controller being further operative for changing the intensity of the laser beam when the control signal is generated.

A method of controlling laser beam intensity, comprising the steps of:

• providing a screen;
• projecting an image on the screen, including emitting a laser beam of an intensity, sweeping the laser beam in mutually orthogonal directions in a pattern of scan lines each having a number of pixels, and illuminating selected pixels with the laser beam to form the image on the screen;
• sensing the intensity of the laser beam, and generating a control signal when the intensity has changed from a reference intensity;
• and
• changing the intensity of the laser beam when the control signal is generated.