Method of and apparatus for multiplying raster scanning lines by modulating a multi-cavity laser diode

• US 8,678,285 B2
• Filed: 09/20/2011
• Issued: 03/25/2014
• 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
• Primary Examiner(s): WALSH, DANIEL I
• Application Number:
  US13/236,984
• Publication Number:
  US 20130068840A1
• Time in Patent Office: 917 Days
• Field of Search: 235/462.01, 235/462.1, 235/462.06, 235/462.11, 235/462.38, 235/462.39, 235/462.4, 235/462.41
• US Class Current: 235/462.01
• 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 operable to scan and read 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 to produce multiple laser beams; and

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

wherein each of said laser beams produced by each cavity of said multi-cavity VLD is spaced apart along an optical axis, and directed towards said rotating scanning element to generate multiple sets of parallel raster 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 scanning lines, and said system reads the bar code symbol.

2. The laser scanning bar code symbol reading system of claim 1, wherein said rotating 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 a first signal corresponding to said detected light intensity during scanning operations;

a signal processor for processing the first signal and converting the processed first signal into a second signal; and

a programmed decode processor for decode processing the second signal and generating symbol character data representative of each bar code symbol scanned by one or more of said multiple sets of raster scanning lines.

6. The laser scanning bar code symbol reading system of claim 5, comprising:

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, comprising a trigger switch associated with said housing.

11. A method of scanning and reading a bar code symbol using a laser scanner, the method comprising the steps of:

(a) in a housing, sequentially activating and driving a plurality of laser cavities of a multi-cavity laser diode to generate, along an optical axis, multiple laser beams, each laser beam being generated from a different laser cavity of said multi-cavity laser diode;

(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 to generate multiple sets of parallel raster scanning lines within said housing;

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

(e) presenting a bar code symbol within said scanning field for scanning by one or more of said multiple sets of parallel raster 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 to generate, along an optical axis, multiple laser beams, each laser beam being generated from a different laser cavity of said multi-cavity laser diode 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 to generate, along an optical axis, multiple laser beams, each laser beam being generated from a different laser cavity of said multi-cavity laser diode during the same laser scanning cycle.

14. The method of claim 11, comprising:

collecting light reflected from a bar code symbol in said scanning field, detecting the intensity of said collected light, and generating a first signal corresponding to said detected light intensity during scanning operations;

processing the first signal and converting the processed first signal into a second signal; and

decode processing the second signal and generating symbol character data representative of each bar code symbol scanned by said parallel raster scanning lines.

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.