Portable laser diode scanning head

Claim 1

In a laser scanning system for reading symbols, a laser scanning head comprising: (a) means including an actuatable laser light source mounted in the head and operative, when actuated, for generating an incident laser beam; (b) optic means mounted in the head for optically forming and directing said incident laser beam along a first optical path toward a reference plane located exteriorly of the head, and to a symbol located in a working distance range in the vicinity of the reference plane, thereby reflecting off the symbol reflected laser light, at least a returning portion of which travels along a second optical path away from the symbol back toward the head, said optic means including a focusing lens and an aperture stop located in the first optical path in the immediate vicinity of the focusing means between the laser light source and the symbol and operative for focusing the incident laser beam to have a beam cross-section of a predetermined size within the working distance range, said aperture stop having a cross-section which is smaller than the beam cross-section at the aperture stop to permit a portion of the incident light beam to pass through the aperture stop en route to the symbol, said cross-section of the aperture stop directly determining said predetermined size of the beam cross-section, said aperture stop being bounded by a blocking wall for obstructing the remaining portion of the incident light beam from passing through the aperture stop en route to the symbol; (c) scanning means mounted in the head for scanning the symbol in a scan across the symbol, said returning portion of said reflected laser light having a variable intensity over the scan; (d) sensor means mounted in the head for detecting the variable intensity of said returning portion of said reflected laser light over a field of view, and for generating an electrical analog signal indicative of the detected variable light intensity; (e) said scanning means being operative for scanning at least one of said incident laser beam and the field of view; (f) signal processing means mounted in the head for processing the analog electrical signal, and for generating a processed signal indicative of the symbol; and (g) manually-actuatable trigger means on the head and operatively connected to, and operative for actuating, the laser beam generating means, scanning means, sensor means and signal processing means to initiate a reading of the symbol upon manual actuation of the trigger means by the user, said trigger means being actuatable for each symbol to be read, each symbol in its respective turn.