METHOD OF AND APPARATUS FOR MULTIPLYING RASTER SCANNING LINES BY MODULATING A MULTI-CAVITY LASER DIODE

• US 20130068840A1
• Filed: 09/20/2011
• Published: 03/21/2013
• Est. Priority Date: 09/20/2011
• Status: Active Grant

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Kearney, Sean Philip
• Granted Patent: US 8,678,285 B2
• Time in Patent Office: Days
• US Class Current: 235/462.1
• CPC Class Codes: G06K 7/10564 Light sources
• CPC Class Codes: G06K 7/10574 Multiple sources
• CPC Class Codes: G06K 7/10613 by rotation, e.g. polygon
• CPC Class Codes: G06K 7/10673 Parallel lines
• CPC Class Codes: G06K 7/1091 means to wake up the scanner from a sleep mode, e.g. using an acceleration sensor indicating that the scanner is being picked up by a user
• CPC Class Codes: G06K 7/1096 the scanner having more than one scanning window, e.g. two substantially orthogonally placed scanning windows for integration into a check-out counter of a super-market

Abstract

A method of and apparatus for generating a multiple raster-type scanning pattern by modulating a multi-cavity laser diode in such a way that it sequentially generates different laser beams synchronously during different laser scanning cycles, while the output laser beams are directed incident upon a rotating polygonal laser scanning element. The system does not require additional moving parts beyond the rotating polygon scanning element so as to reduce complexity and simplify construction of the laser scanning mechanism.

Claims

1. A laser scanning bar code symbol reading system for scanning and reading bar code symbols, said laser scanning bar code symbol reading system having a working range and comprising:

a housing having a light transmission window;

a multi-cavity visible laser diode (VLD) having multiple laser cavities that are sequentially activated and driven so as to produce multiple laser beams; and

a laser scanning mechanism including a rotating polygonal scanning element, having multiple reflective facets, for scanning said multiple laser beams as said rotating polygon element rotates about its axis of rotation;

wherein each said laser beam produced by said multi-cavity visible laser beam is spaced apart along an optical axis, and directed towards said rotating laser scanning element so as to generate multiple sets of raster-type laser scanning lines which are projected through said light transmission window and into a scanning field defined external to said light transmission window, and

wherein when a bar code symbol is presented within said scanning field, the bar code symbol is scanned by one or more of said multiple sets of raster-type laser scanning lines.

2. The laser scanning bar code symbol reading system of claim 1, wherein said rotating laser scanning element is a polygonal scanning element.

3. The laser scanning bar code symbol reading system of claim 1, wherein each said laser beam produced by said multi-cavity visible laser beam is generated during a different laser scanning cycle.

4. The laser scanning bar code symbol reading system of claim 1, wherein each said laser beam produced by said multi-cavity visible laser beam is generated during the same laser scanning cycle.

5. The laser scanning bar code symbol reading system of claim 1, which further comprises:

light collection optics for collecting light reflected/scattered from scanned object in said scanning field, and a photo-detector for detecting the intensity of collected light and generating an analog scan data signal corresponding to said detected light intensity during scanning operations;

an analog scan data signal processor/digitizer for processing the analog scan data signals and converting the processed analog scan data signals into digital scan data signals, which are then converted into digital words representative of the relative width of the bars and spaces in the scanned bar code symbol; and

programmed decode processor for decode processing digitized data signals, and generating symbol character data representative of each bar code symbol scanned by one or more of said multiple sets of raster-type laser scanning lines.

6. The laser scanning bar code symbol reading system of claim 5, which further

an input/output (I/O) communication interface module for interfacing with a host communication system and transmitting symbol character data thereto via wired or wireless communication links that are supported by the symbol reading system and host system;

and

a system controller for generating the necessary control signals for controlling operations within said laser scanning bar code symbol reading system.

7. The laser scanning bar code symbol reading system of claim 1, wherein said housing comprises a hand-supportable housing.

8. The laser scanning bar code symbol reading system of claim 1, wherein said housing comprises a countertop-based housing.

9. The laser scanning bar code symbol reading system of claim 1, wherein said bar code symbol is a code symbol selected from the group consisting of 1D bar code symbols, and 2D stacked bar code symbols.

10. The laser scanning bar code symbol reading system of claim 1, wherein sad laser scanner is activated by manually pulling a trigger switch associated with said housing.

11. A method of scanning a laser scanning a bar code symbol comprising the steps:

(a) in a housing, sequentially activating and driving the laser cavities of a multi-cavity laser diode so as to generate, along an optical axis, multiple laser beams from said multi-cavity laser diode, such that a different laser beam is generated from one of said laser cavities;

(b) within said housing, rotating a polygonal scanning element, with multiple reflective facets, about an axis of rotation;

(c) directing said multiple laser beams towards said rotating polygonal scanning element so as to generate multiple sets of raster-type laser scanning lines within said housing;

(d) projecting said multiple sets of raster-type laser scanning lines through said light transmission window within a scanning field defined external to said light transmission window; and

(d) presenting a bar code symbol within said scanning field for scanning by one or more of said multiple sets of raster-type laser scanning lines.

12. The method of claim 11, wherein step (a) comprises sequentially activating and driving the laser cavities of said multi-cavity laser diode so as to generate, along an optical axis, multiple laser beams from said multi-cavity laser diode, such that each said different laser beam is generated from one of said laser cavities during a different laser scanning cycle.

13. The method of claim 11, wherein step (a) comprises sequentially activating and driving the laser cavities of said multi-cavity laser diode so as to generate, along an optical axis, multiple laser beams from said multi-cavity laser diode, such that each said different laser beam is generated from one of said laser cavities during the same laser scanning cycle.

14. The method of claim 11, which further comprises the following steps performed within said housing:

(c) collecting light reflected/scattered from scanned bar code symbol in said scanning field, and detecting the intensity of said collected light and generating an analog scan data signal corresponding to said detected light intensity during scanning operations;

(d) processing said analog scan data signals and converting the processed analog scan data signals into digital scan data signals, and then converted said digital scan data signals into digital words representative of the relative width of the bars and spaces in the scanned bar code symbol; and

(e) decode processing digitized scan data signals, and generating symbol character data representative of each bar code symbol scanned by said laser scanning beam.

15. The method of claim 11, wherein said bar code symbol is a code symbol selected from the group consisting of 1D bar code symbols, and 2D stacked bar code symbols.