Dual laser scanning code symbol reading system employing automatic object presence detector for automatic laser source selection

• US 8,459,557 B2
• Filed: 03/10/2011
• Issued: 06/11/2013
• Est. Priority Date: 03/10/2011
• Status: Active Grant

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Havens, William H., Colavito, Stephen, Allen, Christopher, Blake, Robert
• Primary Examiner(s): Le, Thien M
• Assistant Examiner(s): LY, TOAN C
• Application Number:
  US13/044,897
• Publication Number:
  US 20120228382A1
• Time in Patent Office: 824 Days
• Field of Search: 235/462.1, 23546222-46223, 2354623-46231
• US Class Current: 235/462.31
• CPC Class Codes: G06K 7/10554 Moving beam scanning
• CPC Class Codes: G06K 7/10792 Special measures in relation to the object to be scanned

Abstract

Method of and system for reading code symbols a dual-laser scanning bar code symbol reading system having the capacity to automatically select in a user-transparent manner, and activate either a near-field source of laser illumination, or a far-field source of laser illumination, using an automatic object presence detection subsystem in the near-field portion of the laser scanning field.

Claims

1. A laser scanning code symbol reading system for reading code symbols comprising:

a housing with a light transmission window;

a laser scanning module, disposed in said housing, for scanning a laser beam across a laser scanning field having a near portion and a far portion defined external to said light transmission window,

wherein said laser scanning module is responsive to one or more control signals generated by a system controller and comprises;

(i) a laser drive module for driving a near-field laser source to produce a near-field laser beam focused within the near portion of said laser scanning field in response to receiving said one or more control signals from said system controller, and for driving a far-field laser source to produce a far-field laser beam in response to receiving said one or more control signals from said system controller, and

(ii) a laser scanning mechanism for scanning said near-field laser beam across said laser scanning field, and a code symbol on an object in said laser scanning field, or scanning said far-field laser beam across said laser scanning field and a code symbol on an object in said laser scanning field;

an automatic object detector disposed in said housing for automatically detecting when said object is present in only the near portion of said laser scanning field, and only generating an object detection event when said object is present in the near portion of said laser scanning field, said automatic object detector being the only object detector in the laser scanning code symbol reading system;

light collection optics, disposed in said housing, for collecting light reflected/scattered from scanned object in said laser scanning field;

a photo-detector, disposed in said housing, for detecting the intensity of collected light from said code symbols, and generating an analog scan data signal corresponding to said detected light intensity during laser scanning operations;

an analog scan data signal processor, disposed in said housing, for processing said analog scan data signals and converting the processed analog scan data signals into digitized data signals;

a programmed decode processor, disposed in said housing, for decode processing said digitized data signals, and generating symbol character data representative of each code symbol scanned by said near-field or far-field laser beam; and

an input/output (I/O) communication interface, disposed in said housing, for interfacing with a host system and transmitting symbol character data to said host system, via a communication link, supported by said laser scanning code symbol reading system and said host system;

said system controller, responsive to the generation of said object detection event, for controlling operations within said laser scanning bar code symbol reading system;

wherein when said system controller detects the generation of said object detection event, said system controller generates said one or more control signals causing said near-field laser source to generate said near-field laser beam and said laser scanning mechanism scans said near-field laser beam across a code symbol on an object in said laser scanning field during laser scanning operations, so as to generate an analog scan data signal which is processed and converted into a digitized data signal, which is then decoded processed in effort to read said code symbol on said object.

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

3. The laser scanning code symbol system of claim 2, which further comprises a trigger switch integrated with said hand-supportable housing, for generating a triggering event in response to the manually pulling of said trigger switch, and wherein said system controller responds to said triggering event.

4. The laser scanning code symbol reading system of claim 1, wherein said automatic object detector is an object presence detection subsystem having a light transmitter for transmitting a light beam into said near field portion of said laser scanning field, and a light receiver for receiving said light beam after being reflected off an object in said near portion of said laser scanning field, and generating said object detection event in response thereto.

5. The laser scanning code symbol reading system of claim 4, wherein said light transmitter and said light receiver are mounted adjacent said light transmission window so as to provide an unobstructed view of an object within said laser scanning field.

6. The laser scanning code symbol reading system of claim 4, wherein said light beam has a continuous low-intensity output level, or has pulsed higher-intensity output level.

7. The laser scanning code symbol reading system of claim 1, wherein said code symbols are symbols selected from the group consisting of 1D bar code symbols, 2D stacked linear bar code symbols and 2D matrix code symbols.

8. The laser scanning code symbol system of claim 1, wherein said communication link is either a wired or wireless communication link.

9. The laser scanning code symbol reading system of claim 1, wherein, in the event that said code symbol is not read after a predetermined number of scanning and decode processing attempts, then said system controller generates said one or more control signals causing said far-field laser source to generate said far-field laser beam and said laser scanning mechanism scans said far-field laser beam across a code symbol on the object located in said laser scanning field during laser scanning operations so as to generate an analog scan data signal which is processed and converted into a digitized data signal, which is then decode processed in effort to read said code symbol on said object.

10. The laser scanning code symbol reading system of claim 9, wherein, in the event that said code symbol is not read after a predetermined number of scanning and decode processing attempts, then said system controller returns to detecting or re-detecting an object in said laser scanning field.

11. A method of reading code symbols comprising the sequence of steps of:

(a) bringing a laser scanning code symbol reading system in proximity with an object bearing one or more code symbols, wherein said laser scanning code symbol reading system comprises;

(i) a housing with a light transmission window;

(ii) a laser scanning module, disposed in said housing, for scanning a laser beam across a laser scanning field having a near portion and a far portion defined external to said light transmission window, wherein said laser scanning module is responsive to one or more control signals generated by a system controller and comprises;

(1) a laser drive module for driving a near-field laser source to produce a near-field laser beam focused within the near portion of said laser scanning field in response to receiving said one or more control signals from said system controller, or driving a far-field laser source to produce a far-field laser beam in response to receiving said one or more control signals from said system controller, and

(2) a laser scanning mechanism for scanning said near-field laser beam across said laser scanning field, and a code symbol on an object in said laser scanning field, or scanning said far-field laser beam across said laser scanning field and a code symbol on an object in said laser scanning field;

(3) an automatic object detector disposed in said housing for automatically detecting when said object is present in only the near portion of said laser scanning field, and only generating an object detection event when said object is present in the near portion of said laser scanning field, said automatic object detector being the only object detector in the laser scanning code symbol reading system;

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

(iii) an analog scan data signal processor, disposed in said housing, for processing said analog scan data signals and converting the processed analog scan data signals into digitized data signals;

(iv) a programmed decode processor, disposed in said housing, for decode processing said digitized data signals, and generating symbol character data representative of each code symbol scanned by said near field laser beam and said far-field laser beam; and

(v) an I/O communication interface for transmitting symbol character data to a host system;

(b) detecting an object in the near portion of said laser scanning field and generating an object detection event;

(c) in response to the generation of said object detection event, said near-field visible laser source generating said near field laser beam, said laser scanning mechanism repeatedly scanning said near field laser beam across any code symbol on the object in the near portion of said laser scanning field, said light collection optics collecting light reflected/scattered from said scanned visible code symbol in said laser scanning field, said photo-detector automatically detecting the intensity of collected light and generating an analog scan data signal corresponding to the light intensity detected during scanning operations, said analog scan data processor processing said analog scan data signal and converting the processed analog scan data signal into a first digitized data signal;

(d) said decode processor processing said first digitized data signal in effort to read a code symbol scanned during step (c); and

(e) in the event that said decode processor reads said code symbol during step (d), then said decode processor producing symbol character data representative of said code symbol, and said I/O communication interface transmitting said symbol character data to a host system.

12. The method of claim 11, wherein step (b) comprises generating said object detection event by automatically detecting said object in said near portion of said laser scanning field using an automatic object detector disposed in said housing.

13. The method of claim 11, wherein said housing comprises a hand-supportable housing.

14. The method of claim 13, wherein said automatic object detector is an object presence detection subsystem having a light transmitter for transmitting a light beam into said near field portion of said laser scanning field, and a light receiver for receiving said light beam after being reflected off an object in said near portion of said laser scanning field, and generating said object detection event in response thereto.

15. The method of claim 14, wherein said light transmitter and said light receiver are mounted adjacent said light transmission window so as to provide an unobstructed view of an object within said laser scanning field.

16. The method of claim 14, wherein said light beam has a continuous low-intensity output level, or has pulsed higher-intensity output level.

17. The method of claim 11, wherein said code symbols are symbols selected from the group consisting of 1D bar code symbols, 2D stacked linear bar code symbols and 2D matrix code symbols.

18. The method of claim 11, wherein said communication link is either a wired or wireless communication link.

19. The method of claim 11, wherein step (b) comprises using a trigger switch integrated with said housing, for generating a triggering event in response to the manually pulling of said trigger switch, and wherein said system controller responds to said triggering event.

20. The method of claim 11, comprising:

(f) in the event that said decode processor cannot read a code symbol during step (d) after one or more attempts at doing so, then said far-field laser source generating said far-field laser beam, said laser scanning mechanism repeatedly scanning said far field laser beam across any code symbol on the object in said laser scanning field, said light collection optics collecting light reflected/scattered from said scanned code symbol in said laser scanning field, said photo-detector automatically detecting the intensity of collected light and generating an analog scan data signal corresponding to the light intensity detected during scanning operations, said analog scan data processor processing said analog scan data signal and converting the processed analog scan data signal into a second digitized data signal;

(g) said decode processor processing said second digitized data signal in effort to read a code symbol scanned during step (f); and

(h) in the event that said decode processor reads a code symbol during step (g), then said decode processor producing symbol character data representative of said code symbol, and said I/O subsystem transmitting said symbol character data to said host system.

21. The method of claim 20, which further comprises:

(i) in the event that said decoder processor cannot read a code symbol during step (g) after one or more attempts at doing so, then said system controller returns control to step (b) and resumes object detection operations.

22. A symbol reading system having a laser scanning field, comprising:

a near-field source of laser illumination for scanning an object in a near portion of said laser scanning field;

a far-field source of laser illumination for scanning an object in a far portion of said laser scanning field;

an automatic object presence detection subsystem for automatically detecting an object only in the near portion of said laser scanning field, and only generating an object detection event when an object is present in the near portion of said laser scanning field, said automatic object presence detection subsystem being the only object presence detection subsystem in the symbol reading system; and

a system controller, responsive to said automatic object presence detection subsystem, for automatically selecting and activating said near-field source of laser illumination when an object is automatically detected in said near portion of said laser scanning field.

23. The symbol reading system of claim 22, comprising:

a decode processor for decode processing signals corresponding to the intensity of light reflected from an object in said laser scanning field and generating data representative of a symbol on an object in said laser scanning field;

wherein, in the event that a symbol is not read after a predetermined number of scanning and decode processing attempts, then said system controller returns to detecting or re-detecting an object in said laser scanning field.

24. The symbol reading system of claim 22, wherein said automatic object presence detection subsystem comprises:

a light transmitter for transmitting a light beam into said near field portion of said laser scanning field; and

a light receiver for receiving said light beam after said light beam is reflected off an object in said near portion of said laser scanning field.