Holographic-based bar code symbol position detection system for producing bar code symbol position data specifying the position of a detected bar code symbol within a 3-D scanning volume above a conveyor belt structure

• US 6,290,132 B1
• Filed: 02/17/1999
• Issued: 09/18/2001
• 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:
  US09/251,675
• Time in Patent Office: 944 Days
• Field of Search: 235/462.01, 235/472.01, 235/462.07, 235/462.08, 235/462.09, 235/462.1, 235/462.11, 235/462.22, 235/462.23, 235/462.32, 235/462.34, 235/462.35
• US Class Current: 235/462.39
• 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 provisions 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 laser scanning system capable of producing information specifying the subregion of space within a 3-D scanning volume within which a bar code symbol is detected by a laser scanning pattern. The system comprises a laser scanning pattern generator, a scan data processor, a bar code symbol position data generator and a system controller. In the illustrative embodiment, the laser scanning pattern generator employs a holographic scanning disc to generate an omnidirectional laser scanning pattern within the 3-D scanning volume for scanning a bar code symbol presented therein, and in response thereto, automatically produces scan data indicative of the scanned bar code symbol. The scan data processor automatically processes the produced scan data so as to detect the scanned bar code symbol within the 3-D scanning volume. The bar code symbol position data generator automatically determines a subregion of space within the 3-D scanning volume wherewithin the detected bar code symbol is scanned by the laser scanning pattern, and automatically produces bar code symbol position data indicative of this subregion of space. By virtue of the present invention, it is now possible to generate, on a real-time basis, information specifying the position of a detected bar code symbol anywhere within the prefined 3-D scanning volume of a laser scanning system.

Claims

1. A holographic-based bar code symbol position detection system capable of producing bar code symbol position data specifying the position of a detected bar code symbol within a 3-D scanning volume disposed above a conveyor belt structure, said holographic-based bar code symbol position detection system comprising:

a housing having a light transmission aperture, and supportable above a conveyor belt structure along which objects bearing bar code symbols are transported; and

a holographic-based laser scanning mechanism disposed within said housing, and including

a holographic scanning disc rotatable about an axis of rotation,

a plurality of laser beam sources for producing a plurality of laser beams and directing said plurality of laser beams at an angle of incidence to said holographic scanning disc,

said holographic scanning disc having a plurality of holographic optical elements disposed thereon for scanning said plurality of laser beams and producing an omnidirectional laser scanning pattern for scanning a bar code symbol on an object transported along said conveyor belt structure, and collecting light rays reflected off said scanned bar code symbol for subsequent focusing and detection,

a plurality of light reflective surfaces disposed beneath said holographic scanning disc, and each said light reflective surface focusing the reflected light rays collected by each said holographic optical element, towards a focal point,

a plurality of photodetectors, each said photodetector being disposed at one said focal point, for detecting the intensity of collected light rays focused by said one light reflective surface and transmitted through said holographic optical elements to said photodetector for detection and generation of a scan data signal, and

a scan data processor for automatically processing said scan data signal produced from said holographic-based laser scanning mechanism so as to detect each said scanned bar code symbol within said 3-D scanning volume, and produce bar code symbol position data specifying the position of said detected bar code symbol within said 3-D scanning volume.

2. The holographic-based bar code symbol position detection system of claim 1, wherein said 3-D scanning volume has multiple focal zones and a depth of field of at least 24 inches.

3. The holographic-based bar code symbol position detection system of claim 1, wherein said scan data processor further comprises a bar code symbol decoder for automatically processing said produced scan data so as to decode said detected bar code symbol within said 3-D scanning volume.

4. The holographic-based bar code symbol position detection system of claim 1, wherein said holographic-based laser scanning mechanism further comprises a mechanism for determining which of said plurality of holographic optical elements produced the laser beam that scanned said bar code symbol and produced said scan data therefrom, and wherein said scan data processor automatically produces said bar code symbol position data based on said holographic optical element determined by said mechanism.