Laser scanning system using laser beam sources for producing long and short wavelengths in combination with beam-waist extending optics to extend the depth of field thereof while resolving high resolution bar code symbols having minimum code element widths

• US 9,064,165 B2
• Filed: 03/28/2012
• Issued: 06/23/2015
• Est. Priority Date: 03/28/2012
• Status: Active Grant

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Havens, William, Kearney, Sean Philip
• Primary Examiner(s): Le, Thien M
• Assistant Examiner(s): Habib, Asifa
• Application Number:
  US13/432,197
• Publication Number:
  US 20130256418A1
• Time in Patent Office: 1,182 Days
• Field of Search: 235/383, 235/462.33, 235/454, 235/462.4, 348/234
• US Class Current: 1/1
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B
• 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 laser scanning bar code symbol reading system having a scanning window, from which blue/red beam-waist-extended laser scanning planes are projected and intersect within an extended depth of field (DOF) defined adjacent the scanning window. In the illustrative embodiment, the laser scanning bar code symbol reading system includes a laser scanning subsystem having: a dual laser sources for producing a laser beams having blue and red spectral components; a collimating lens for collimating the laser beams; an aperture stop for shaping the cross-sectional dimensions of the collimated the laser beams; and beam-waist extending optics (e.g. axicon-lens) for extending the waist of the laser beam having a red characteristic wavelength.

Claims

1. A bar code symbol reading system comprising:

a system housing having a scanning window;

a laser scanning subsystem disposed in said system housing, generating and projecting a laser scanning plane through said scanning window and into a scanning field, scanning one or more objects within said scanning field, and producing scan data signals for decode processing;

wherein said laser scanning plane has a full-field region within said scanning field, and a limited-field region within said scanning field; and

wherein said laser scanning subsystem includes

(i) a beam scanning mechanism for scanning first and second laser scanning beams across said laser scanning field to produce said laser scanning plane;

(ii) a first laser source generating said first laser beam having a beam waist extending over the full-field region of said laser scanning plane generated using said first laser source and said beam scanning mechanism, and beam-waist extending optics extending the beam waist of said first laser beam over the full-field region of said laser scanning plane during scanning operations, wherein said first laser beam comprises red spectral components; and

(iii) a second laser source generating said second laser beam having a beam waist extending over the limited-field region of said laser scanning plane generated using said second laser source and said beam scanning mechanism, wherein said second laser beam comprises blue spectral components; and

a scan data processor for processing said scan data signals produced by said laser scanning subsystem in effort to read a bar code symbol on said object passed through said scanning field and scanned by said laser scanning field, and generate symbol character data representative of said read bar code symbol; and

a system controller for controlling the operation of said laser scanning subsystem during said system operation.

2. The bar code symbol reading system of claim 1, wherein said first and second laser beams are generated and scanned simultaneously, to produce said laser scanning field.

3. The bar code symbol reading system of claim 1, wherein said first and second laser beams are generated and scanned alternatively, to produce said laser scanning field.

4. The bar code symbol reading system of claim 1, wherein said system housing is either counter-top mounted or hand-supportable.

5. The bar code symbol reading system of claim 1, wherein said first laser source further comprises beam-waist extending optics selected from the group consisting of:

a cubic phase mask;

a phase modulation plate;

an axicon lens or a rotationally symmetric prism;

a multi-focal lens;

a Mathieu or Mathieu-Gaussian filter;

an asymmetrical optical element;

an optical assembly using an apodization element and a negative bi-prism;

a conical lens; and

other functionally equivalent devices.

6. The bar code symbol reading system of claim 1, wherein said second laser beam has a smaller spot size within the limited-field region than said first laser beam for reading high-density bar codes.

7. A method of operating a bar code symbol reading system comprising the steps of:

(a) providing a bar code symbol reading system, including;

a system housing having a scanning window, and a laser scanning subsystem disposed in said system housing, generating and projecting a laser scanning plane through said scanning window and into a scanning field,

wherein said laser scanning plane has a full-field region within said scanning field, and a limited-field region within said scanning field; and

wherein said laser scanning subsystem includes

(i) a beam scanning mechanism scanning one or more laser scanning beams across said laser scanning field to produce said laser scanning plane;

(ii) a first laser source generating a first laser beam having a beam waist extending over the full-field region of said laser scanning plane generated using said first laser source and said beam scanning mechanism, and beam-waist extending optics extending the beam waist of said first laser beam over the full-field region of said laser scanning plane during scanning operations, wherein said first laser beam comprises red spectral components;

(iii) a second laser source generating a second laser beam having a beam waist extending over the limited-field region of said laser scanning plane generated using said second laser source and said beam scanning mechanism, wherein said second laser beam comprises blue spectral components;

(iv) a scanning element scanning said first and second laser beams so as to generate said laser scanning plane within said scanning field; and

(v) a scan data processor for processing said scan data signals produced by said laser scanning subsystem in effort to read a bar code symbol on each object passed through said scanning field, and generate symbol character data representative of each said read bar code symbol;

(b) generating and projecting said laser scanning planes through said scanning window, and into said scanning field, for scanning one or more objects within said scanning field and producing scan data for decode processing; and

(c) processing said scan data produced by said laser scanning subsystem in effort to read a bar code symbol on said object passed through said scanning field, and generating symbol character data representative of said read bar code symbol.

8. The method of claim 7, wherein said system housing is either counter-top mounted or hand-supportable.

9. A bar code symbol reading system comprising:

a system housing having a scanning window;

a laser scanning subsystem disposed in said system housing, generating and projecting a plurality of laser scanning planes through said scanning window, which intersect within a 3D scanning volume defined adjacent said scanning window and provide a laser scanning pattern within said 3D scanning volume, scanning one or more objects within said 3D scanning volume and producing scan data for decode processing;

wherein said each said laser scanning plane has a full-field region within said 3D scanning volume, and a limited-field region within said 3D scanning volume; and

wherein said laser scanning subsystem includes

(i) a first laser source generating a first laser beam having a first wavelength comprising red spectral components and a beam waist extending over the full-field region of each laser scanning plane generated from said first laser beam, and beam-waist extending optics extending the beam waist of said first laser beam over the full-field region of the laser scanning plane generated from said first laser beam; and

(ii) a second laser source generating a second laser beam having a second wavelength comprising blue spectral components and a beam waist extending over the limited-field region of each laser scanning plane generated from said second laser beam;

a scan data processor for processing said scan data produced by said laser scanning subsystem in effort to read a bar code symbol on said object passed through said 3D scanning volume, and generate symbol character data representative of said read bar code symbol; and

a system controller for controlling the operation of said laser scanning subsystem during said system operation.

10. The bar code symbol reading system of claim 9, wherein said laser scanning pattern is an omni-directional laser scanning pattern within said 3D scanning volume.

11. The bar code symbol reading system of claim 9, wherein said first laser source further comprises beam-waist extending optics selected from the group consisting of:

a cubic phase mask;

a phase modulation plate or phase;

an axicon lens or a rotationally symmetric prism;

a multi-focal lens;

a Mathieu or Mathieu-Gaussian filter;

an asymmetrical optical element;

an optical assembly using an apodization element and a negative bi-prism;

a conical lens; and

other functionally equivalent devices.

12. The bar code symbol reading system of claim 9, wherein said system housing is either counter-top mounted or hand-supportable.

13. The bar code symbol reading system of claim 9 realized as a bioptical laser scanning system, wherein said system housing has a horizontal housing section provided with a horizontal scanning window, and a vertical housing section provided with a vertical scanning window;

wherein one said laser scanning subsystem is installed in said horizontal scanning window to generate a first plurality of laser scanning planes through said horizontal scanning window, and one said laser scanning subsystem is installed in said vertical scanning window to generate a second plurality of laser scanning planes through said vertical scanning window;

wherein said first and second plurality of laser scanning planes intersect within a 3D scanning volume defined adjacent said horizontal and vertical scanning windows and provide a laser scanning pattern within said 3D scanning volume, for scanning one or more objects within said 3D scanning volume and producing scan data for decode processing; and

wherein said each said laser scanning plane has a full-field region within said 3D scanning volume, and a limited-field region within said 3D scanning volume.