Retro-reflective scanner with return path free of collection optics

• US 5,272,353 A
• Filed: 06/19/1992
• Issued: 12/21/1993
• Est. Priority Date: 06/19/1992
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Barkan, Edward, Shepard, Howard M.
• Primary Examiner(s): Nelms, David C.
• Application Number:
  US07/901,305
• Time in Patent Office: 550 Days
• Field of Search: 250/234, 250/235, 250/236, 250/566, 250/568, 235/467, 235/472, 359/213, 359/214
• US Class Current: 250/566
• CPC Class Codes: G06K 7/10554 Moving beam scanning
• CPC Class Codes: G06K 7/10594 Beam path

Abstract

Collection optics are eliminated in the return path of a retro-reflective scanner for reading bar code symbols.

Claims

1. A retro-reflective electro-optical scanner for reading indicia having parts of different light reflectivity, comprising:

(a) means for generating and directing a light beam along an outgoing path;

(b) a reflector mounted in the outgoing path for reflecting the light beam toward the indicia for reflection therefrom;

(c) detector means for detecting light reflected off the indicia over a field of view in a return path free of any means for optically focusing and optically limiting said field of view, and for generating an electrical signal representative of the indicia;

(d) said reflector also being mounted in the return path for directly receiving the reflected light from the indicia and for directly reflecting the reflected light to the detector means; and

(e) means for moving the reflector to simultaneously scan the light beam and the field of view.

2. The retro-reflective scanner according to claim 1, wherein the light beam generating means includes a laser diode having an outlet facing the reflector means, and wherein the detector means includes a photodetector having an inlet facing the reflector means.

4. The retro-reflective scanner according to claim 1, wherein the moving means reciprocally oscillates the reflector.

5. The retro-reflective scanner according to claim 1, wherein the outgoing and return paths intersect adjacent to the reflector.

3. The retro-reflective scanner according to claim l, wherein the reflector includes a generally planar mirror extending across the outgoing and return paths.

6. A method of electro-optically reading indicia having parts of different light reflectivity, comprising the steps of:

(a) generating and directing a light beam along an outgoing path;

(b) reflecting the light beam toward the indicia for reflection therefrom by mounting a reflector in the outgoing path;

(c) detecting light reflected off the indicia by a photodetector over a field of view in a return path free of any means for optically focusing and optically limiting said field of view, and for generating an electrical signal representative of the indicia;

(d) said reflector also being mounted in the return path for directly receiving the reflected light from the indicia, and for directly reflecting the reflected light to the detector means; and

(e) means for moving the reflector to simultaneously scan the light beam and the field of view.

7. The method according to claim 6, wherein the directing step is performed by pointing a laser diode at the reflector, and wherein the detecting step is performed by pointing the photodetector at the reflector.

8. The method according to claim 6, wherein the moving step is performed by reciprocally oscillating the reflector.

9. A retro-reflective electro-optical multi-component scanner for reading indicia having parts of different light reflectivity, comprising:

(a) a laser in the scanner for emitting a laser beam along an outgoing path;

(b) a generally planar reflector mounted in the outgoing path for directly receiving and reflecting the laser beam outwardly of the scanner toward the indicia for reflection therefrom;

(c) a detector in the scanner for detecting laser light reflected off the indicia over a field of view in a return path free of any means for optically focusing and optically limiting said field of view, and for generating an electrical signal representative of the indicia;

(d) said generally planar reflector also being mounted int he return path for directly receiving the reflected laser light from the indicia, and for directly reflecting the reflected laser light to the detector; and

(e) means for moving the generally planar reflector to simultaneously scan the laser beam and the field of view, said generally planar reflector being the sole movable component int he scanner.