Holographic laser scanning system and process and apparatus and methods for designing and constructing the same

• US 6,062,479 A
• Filed: 10/03/1997
• Issued: 05/16/2000
• Est. Priority Date: 08/17/1994
• Status: Expired due to Fees

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Dickson, LeRoy, Amundsen, Thomas, Knowles, Carl Harry, Groot, John
• Primary Examiner(s): Le, Thien Minh
• Application Number:
  US08/943,536
• Time in Patent Office: 956 Days
• Field of Search: 235/462, 235/467, 235/469, 235/470, 235/472, 235/462.01, 235/162.09, 235/462.1, 235/462.11, 235/462.24, 235/462.25, 235/462.41, 235/472.01
• US Class Current: 235/472.02
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 26/106 having diffraction gratings as scanning elements, e.g. holographic scanners holographic optical elements G02B5/32, holography G03H
• CPC Class Codes: G06K 17/0022 arrangements or provisious for transferring data to distant stations, e.g. from a sensing device "transfer between computer elements G06F13/00 "; data-transmission H04L
• CPC Class Codes: G06K 2207/1012 Special detection of object
• CPC Class Codes: G06K 2207/1013 Multi-focal
• CPC Class Codes: G06K 2207/1016 Motor control or optical moving unit control
• CPC Class Codes: G06K 2207/1017 Programmable
• CPC Class Codes: G06K 2207/1018 Source control
• CPC Class Codes: G06K 7/10 by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
• CPC Class Codes: G06K 7/10564 Light sources
• CPC Class Codes: G06K 7/10584 Source control
• CPC Class Codes: G06K 7/10594 Beam path
• CPC Class Codes: G06K 7/10603 Basic scanning using moving elements
• CPC Class Codes: G06K 7/10663 using hologram
• CPC Class Codes: G06K 7/10673 Parallel lines
• CPC Class Codes: G06K 7/10693 for omnidirectional scanning
• CPC Class Codes: G06K 7/10702 Particularities of propagating elements, e.g. lenses, mirrors G06K7/10831 takes precedence
• CPC Class Codes: G06K 7/10792 Special measures in relation to the object to be scanned
• CPC Class Codes: G06K 7/10801 Multidistance reading
• CPC Class Codes: G06K 7/10811 : Focalisation
• CPC Class Codes: G06K 7/10851 : Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06K 7/10861 : sensing of data fields affixed to objects or articles, e.g. coded labels postal sorting B07C3/14, conveying articles B65G47/48
• CPC Class Codes: G06K 7/10871 : randomly oriented data-fields, code-marks therefore, e.g. concentric circles-code
• CPC Class Codes: G06K 7/10881 : constructional details of hand-held scanners
• CPC Class Codes: G06K 7/10891 : the scanner to be worn on a finger or on a wrist
• CPC Class Codes: G06K 7/109 : adaptations to make the hand-held scanner useable as a fixed scanner
• CPC Class Codes: G06K 7/14 : using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G07F 9/002 : Vending machines being part of a centrally controlled network of vending machines
• CPC Class Codes: G07G 1/0045 : with a code reader for reading of an identifying code of the article to be registered, e.g. barcode reader or radio-frequency identity [RFID] reader
• CPC Class Codes: G07G 1/0054 : with control of supplementary check-parameters, e.g. weight or number of articles

Abstract

A holographic laser scanning system comprising a support disc rotatable about an axis of rotation, and having an inner perimeter, an outer perimeter, and an available light collecting region defined between the inner perimeter and the outer perimeter. A laser light source produce a laser beam having first and second components characterized by first and second polarization states, respectively. A plurality of holographic optical elements are supported on the support disc between the inner and outer perimeters, for scanning the laser beam and producing a laser scanning pattern for scanning a code symbol. Each holographic optical element has a beam steering portion disposed adjacent the outer perimeter for scanning the laser beam, and a light collecting portion disposed between the inner and outer perimeters for collecting laser light reflected off a code symbol scanned by the laser beam. The beam steering portion of each holographic optical element has a light diffraction efficiency that is optimized for the first polarization state of the laser beam incident thereon, and the light collecting portion of each holographic optical element has a light diffraction efficiency optimized for the second polarization state of laser light reflected off the scanned code symbol. A photodetector is provided for detecting laser light reflected off the scanned code symbol. A polarization-selective filter is disposed before photodetector for transmitting collected laser light having second polarization state and blocking collected laser light having the first polarization state, thereby reducing the effects of glare produced when the laser beam scans bar code symbols on glossy substrates.

Claims

1. A holographic laser scanning system, comprising:

a support disc rotatable about an axis of rotation, and having an inner perimeter, an outer perimeter, and an available light collecting region defined between said inner perimeter and said outer perimeter;

a laser light source for producing a laser beam having first and second components characterized by first and second polarization states, respectively, said first polarization state being orthogonal to said second polarization state;

a plurality of holographic optical elements supported on said support disc between said inner and outer perimeters, for scanning said laser beam and producing a laser scanning pattern for scanning a code symbol,

each said holographic optical element having a beam steering portion disposed adjacent said outer perimeter for scanning said laser beam, and a light collecting portion disposed between said inner and outer perimeters for collecting laser light reflected off a code symbol scanned by said laser beam,

wherein said beam steering portion of each said holographic optical element has a light diffraction efficiency that is optimized for said first polarization state of said laser beam incident thereon, and said light collecting portion of each holographic optical element has a light diffraction efficiency optimized for said second polarization state of laser light reflected off said scanned code symbol;

a photodetector for detecting laser light reflected off said scanned code symbol; and

a polarization-selective filter disposed before said photodetector for transmitting collected laser light having said second polarization state and blocking collected laser light having said first polarization state.

2. The holographic laser scanning system of claim 1, wherein said laser light source is a laser diode for producing a visible laser beam.

3. The holographic laser scanning system of claim 1, wherein said photodetector is disposed above said support disc.

4. The holographic laser scanning system of claim 1, wherein said polarization-selective filter operates to reduce the effects of glare produced when said laser beam is scanned across said code symbol.

5. The holographic laser scanning system of claim 1, wherein each said holographic optical element is a volume hologram.

6. The holographic laser scanning system of claim 5, wherein each said volume hologram is a transmission-type volume hologram.

7. A holographic laser scanning system, comprising:

a support disc rotatable about an axis of rotation, and having an inner perimeter, an outer perimeter, and an available light collecting region defined between said inner perimeter and said outer perimeter;

a plurality of laser light sources for producing a plurality of laser beams, each said laser beam having first and second components characterized by first and second polarization states, respectively, said first polarization state being orthogonal to said second polarization state;

a plurality of holographic optical elements supported on said support disc, between said inner and outer perimeters, for scanning said plurality of laser beams and producing a laser scanning pattern for scanning a code symbol,

each said holographic optical element having a beam steering portion disposed adjacent said outer perimeter for scanning each said laser beam, and a light collecting portion disposed between said inner and outer perimeters for light collecting laser light reflected off a code symbol scanned by at least one said laser beam,

wherein said beam steering portion of each said holographic optical element has a light diffraction efficiency that is optimized for said first polarization state of said laser beam incident thereon, and said light collecting portion of each holographic optical element has a light diffraction efficiency optimized for said second polarization state of laser light reflected off said scanned code symbol;

a plurality of photodetectors, each said photodetector being associated with one said laser light source and being capable of detecting laser light reflected off a code symbol scanned by the laser beam produced by said associated laser light source; and

a plurality of polarization-selective filters, each being disposed before one said photodetector for transmitting collected laser light having said second polarization state and blocking collected laser light having said first polarization state.

8. The holographic laser scanning system of claim 7, wherein each said laser light source is a laser diode for producing a visible laser beam.

9. The holographic laser scanning system of claim 7, wherein each said photodetector is disposed above said holographic scanning disc.

10. The holographic laser scanning system of claim 7, wherein each said polarization-selective filter operates to reduce the effects of glare produced when said laser beam is scanned across said code symbol.

11. The holographic laser scanning system of claim 7, wherein each said holographic optical element is a volume hologram.

12. The holographic laser scanning system of claim 11, wherein each said volume hologram is a transmission-type volume hologram.