Abstract: A unitary hand-held bar code scanner and reader produces an elliptical beam, oriented with its major axis along the direction of the bars, utilizing optics employing far field diffraction effects to shape the beam and maintain its elliptical aspect (length to width ratio) constant over a distance in front of the scanner were bar codes may be located. The optics eliminates parallax even though the photodetector and light source (preferably a laser diode) are located offset from each other on a board on which the optics are mounted. A housing assembly has channels which mount the board therein without shock absorbing devices. A digital microcomputer controller and peripheral devices regulate the optical power output from the laser diode and prevents catastrophic failure, if the electrical current through the laser diode exceeds safe limits.

Abstract: An optical scanner unit has a window which transmits light from inside the scanner to a target, for example, a bar code, and receives light from a target into the scanner. The window is tilted at Brewster's angle to permit light from inside the scanner to exit the scanner without "exit reflection" of light off the interior of the window. The window also permits light returned from the scanned target to enter the scanner and be sensed by a photodetector therein. The same window may be used for light transmitted to the photodetector and from the light source. The window is disposed at Brewster's angle relative to the scanning beam at the center of scan, and is close to Brewster's angle over the entire scan.