Holographic laser scanning system having multiple laser scanning stations for producing a 3-D scanning volume substantially free of spatially and temporally coincident scanning planes

• US 6,158,659 A
• Filed: 10/14/1997
• Issued: 12/12/2000
• 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: Knowles, C. Harry, Dickson, LeRoy, Check, Frank, Groot, John
• Primary Examiner(s): LE, THIEN MINH
• Application Number:
  US08/949,915
• Time in Patent Office: 1,155 Days
• Field of Search: 235/462.01, 235/462.21, 235/462.22, 235/462.23, 235/462.24, 235/462.25, 235/462.26, 235/462.34, 235/462.35, 235/462.36, 235/462.4 1, 356/356, 356/363, 356/351
• US Class Current: 235/462.01
• 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: G02B 5/32 Holograms used as optical elements
• 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 2207/1016 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: G06Q 10/087 : Inventory or stock management, e.g. order filling, procurement or balancing against orders
• 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 scanner of ultra-compact design capable of reading bar and other types of graphical indicia within a large scanning volume using holographic optical elements and visible laser diodes. The holographic optical elements are arranged on the scanning disc in such a manner so that none of the laser scanning planes generated within the 3-D scanning volume of the system are spatially and temporally coincident with any other laser scanning plane within the 3-D scanning volume. This novel feature of the present invention ensures that there is substantially zero cross-talk at the plurality of photodetectors provided within the system, significantly improving the performance of the system.

Claims

1. A holographic laser scanning system for producing a 3-D scanning volume substantially free of spatially and temporally coincident laser scanning planes, said holographic laser scanning system comprising:

a housing;

a plurality of laser sources disposed within said housing, for producing a plurality of laser beams;

holographic scanning disc disposed within said housing, rotating about an axis of rotation, and having a plurality of holographic optical elements for scanning said plurality of laser beams and producing within a 3-D scanning volume, a plurality of laser scanning planes for scanning a code symbol;

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

wherein said plurality of holographic optical elements are physically ordered about said holographic scanning disc so that substantially none of said laser scanning planes within said 3-D scanning volume are spatially and temporally coincident with any other laser scanning plane in order to ensure that there is substantially zero cross-talk at said plurality of photodetectors.

2. The holographic laser scanning system of claim 1, wherein each said laser scanning plane has predefined beam characteristics;

and

said plurality of laser scanning planes intersect within said 3-D scanning volume and said predefined beam characteristics of said scanning planes cooperate within said 3-D scanning volume so as to produce an omnidirectional laser scanning pattern within said 3-D scanning volume for omnidirectional scanning anywhere therewithin, code symbols having a predetermined bar/space resolution.

3. The holographic laser scanning system of claim 1, wherein said 3-D scanning volume has at least three focal zones, and a depth of field of at least 10 inches.

4. The holographic laser scanning system of claim 1, wherein said 3-D scanning volume is in the shape of a 3-D polygonal shaped object.

5. The holographic laser scanning system of claim 4, wherein said 3-D polygonal shaped object has at least four substantially rectangular shaped side surfaces.

6. The holographic laser scanning system of claim 1, wherein each said laser source comprises a laser diode for producing one said visible laser beam.

7. The holographic laser scanning system of claim 6, wherein said laser diodes are symmetrically arranged about said holographic scanning disc.

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

9. The holographic laser scanning system of claim 8, wherein each said volume hologram is a transmission-type volume hologram.

10. The holographic laser scanning system of claim 1, wherein said plurality of laser sources comprises at least three laser diodes, said plurality of holographic optical elements comprises at least sixteen volume transmission holograms, and said plurality of laser scanning planes comprises at least forty-eight laser scanning planes, none of which are spatially and temporally coincident with any other laser scanning plane, thereby ensuring that there is substantially zero cross-talk at said plurality of said photodetectors.