RFID conveyor system

• US 7,592,915 B2
• Filed: 03/23/2006
• Issued: 09/22/2009
• Est. Priority Date: 03/29/2005
• Status: Active Grant

• Current Assignee: Datalogic USA, Inc.
• Original Assignee: Accu-Sort Systems Incorporated (Datalogic S.p.A.)
• Inventors: Liu, Zhong-Min
• Primary Examiner(s): Nguyen; Phung
• Application Number:
  US11/387,629
• Publication Number:
  US 20060232422A1
• Time in Patent Office: 1,279 Days
• Field of Search: 3405721-5729, 343/751, 343/866, 235/435
• US Class Current: 340/572.1
• CPC Class Codes: B07C 5/3412 according to a code applied to the object which indicates a property of the object, e.g. quality class, contents or incorrect indication sorting according to size measured by light-responsive means B07C5/10; sorting according to optical properties B07C5/342; for packages B65D79/02; for information carriers G06K7/00
• CPC Class Codes: B65G 2203/042 Sensors
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
• CPC Class Codes: G06K 2207/1012 Special detection of object
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: G06K 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: G06K 7/10346 the antenna being of the far field type, e.g. HF types or dipoles
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G06K 7/10435 the interrogation device being positioned close to a conveyor belt or the like on which moving record carriers are passing conveying in accordance with bodily destination marks, see B65G47/46, sorting of objects carrying identity markings, see B07C5/34
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 1/2241 used in or for vehicle tyres
• CPC Class Codes: H01Q 17/001 for modifying the directional characteristic of an aerial
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40
• CPC Class Codes: H01Q 9/0428 : radiating a circular polarised wave

Abstract

A conveyor system processes items on which radio frequency identification tags are disposed and includes a frame and a conveyor that is disposed moveably on the frame and that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon. An antenna is disposed on the frame with respect to the path of travel so that the antenna radiates radio frequency signals into a first area through which the items pass. The antenna comprises a substrate and a plurality of patch elements having respective generally planar surfaces and that are disposed on the substrate in respecting positions that are sequential with respect to a direction transverse to the path of travel. The generally planar surfaces of the patch elements are generally coplanar. The antenna includes a feed network that applies respective signals to each patch element that drive electric current at the patch elements to radiate the radio frequency signals. The respective signals applied by the feed network to at least two patch elements define a predetermined phase shift with respect to each other. A radio frequency transmitter drives the antenna to emit the radio frequency signals.

Claims

1. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:

a frame;

a conveyor that is disposed movably on the frame and that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon;

an antenna disposed on the frame with respect to the path of travel so that the antenna radiates radio frequency signals into a first area through which the items pass, wherein the antenna comprises a substrate and a plurality of patch elements having respective generally planar surfaces and that are disposed on the substrate in respective positions that are sequential with respect to a direction transverse to the path of travel,

wherein the generally planar surfaces of the patch elements are generally coplanar,

wherein the antenna includes a feed network that applies respective signals to each said patch element that drive electric current at the patch elements to radiate the radio frequency signals,

wherein the antenna is disposed with respect to the conveyor and the path of travel so that respective said radio frequency identification tags on said items are detected by a near field component of the radio frequency signal radiated by one of the patch elements without interference from the other patch elements, and

wherein the respective signals applied by the feed network to at least two said patch elements define a predetermined phase shift with respect to each other that is fixed so that respective electric current patterns on the at least two patch elements are out of phase with each other; and

a radio frequency transmitter that drives the antenna to emit the radio frequency signals into the first area.

2. The system as in claim 1, wherein the respective signals applied by the feed network to each pair of adjacent said patch elements define the predetermined phase shift with respect to each other.

3. The system as in claim 2, wherein the predetermined phase shift between each pair of said adjacent patch elements is the same.

4. The system as in claim 3, wherein the predetermined phase shift between each pair of said adjacent patch elements is approximately 90 degrees.

5. The system as in claim 1, wherein the feed network applies the respective signals from a common source, and wherein the predetermined phase shift is defined by lengths of traces in the feed network between the common source and respective said patch elements.

6. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:

a frame;

a generally planar belt that is disposed movably on the frame and that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon;

an antenna disposed on the frame beneath the belt and comprising a substrate and a plurality of patch elements having respective generally planar surfaces and that are disposed on the substrate in respective positions that are sequential with respect to a direction transverse to the path of travel, the antenna being oriented with respect to the belt so that the antenna radiates radio frequency signals into a first area that is proximate the belt and through which the items pass,

wherein the generally planar surfaces of the patch elements are generally coplanar,

wherein the antenna includes a feed network that applies respective signals to each said patch element that drive electric current at the patch elements to radiate the radio frequency signals,

wherein the antenna is disposed with respect to the belt and the path of travel so that respective said radio frequency identification tags on said items are detected by a near field component of the radio frequency signal radiated by one of the patch elements without interference from the other patch elements, and

wherein the respective signals applied by the feed network to at least two said patch elements define a predetermined phase shift with respect to each other that is fixed so that respective electric current patterns on the at least two patch elements are out of phase with each other; and

a radio frequency transmitter that drives the antenna to emit the radio frequency signals into the first area.

7. The system as in claim 6, wherein the respective signals applied by the feed network to each pair of adjacent said patch elements define the predetermined phase shift with respect to each other.

8. The system as in claim 7, wherein the predetermined phase shift between each pair of said adjacent patch elements is the same.

9. The system as in claim 8, wherein the predetermined phase shift between each pair of said adjacent patch elements is approximately 90 degrees.

10. The system as in claim 6, wherein the feed network applies the respective signals from a common source, and wherein the predetermined phase shift is defined by lengths of traces in the feed network between the common source and respective said patch elements.

11. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:

a frame;

a generally planar belt that is disposed movably on the frame and that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon;

an antenna disposed on the frame beneath the belt and comprising a substrate and a plurality of patch elements having generally planar surfaces and that are disposed on the substrate in tandem with respect to a direction transverse to the path of travel, the antenna being oriented with respect to the belt so that the antenna

radiates radio frequency signals into a first area that is proximate the belt and through which the items pass and

receives responses to the radio frequency signals from the respective radio frequency identification tags on the items on the belt,

wherein the generally planar surfaces of the patch elements are generally coplanar,

wherein the antenna includes a feed network that applies respective signals to each said patch element that drive electric current at the patch elements to radiate the radio frequency signals,

wherein the antenna is disposed with respect to the belt and the path of travel so that respective said radio frequency identification tags on said items are detected by a near field component of the radio frequency signal radiated by one of the patch elements without interference from the other patch elements, and

wherein the respective signals applied by the feed network to each pair of adjacent said patch elements define a predetermined phase shift with respect to each other that is fixed so that respective electric current patterns on the pair of adjacent patch elements are out of phase with each other;

a radio frequency transmitter that drives the antenna to emit the radio frequency signals into the first area; and

a radio frequency receiver that receives signals from the antenna corresponding to the responses received by the antenna from the respective radio frequency identification tags and outputs first signals corresponding to the responses.

12. The system as in claim 11, wherein the predetermined phase shift between each said pair of adjacent patch elements is the same.

13. The system as in claim 12, wherein the predetermined phase shift is approximately 90 degrees.

14. The system as in claim 11, wherein the feed network applies the respective signals from a common source, and wherein the predetermined phase shift is defined by lengths of traces in the feed network between the common source and respective said patch elements.

15. A method of processing items on which radio frequency identification tags are disposed, said method comprising the steps of:

providing a frame;

providing a conveyor disposed movably on the frame that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon;

providing an antenna on the frame with respect to the path of travel so that the antenna radiates radio frequency signals into a first area through which the items pass, wherein the antenna comprises a substrate and a plurality of patch elements having respective generally planar surfaces and that are disposed on the substrate in respective positions that are sequential with respect to a direction transverse to the path of travel,

wherein the generally planar surfaces of the patch elements are generally coplanar, and

wherein the antenna includes a feed network that applies respective signals to each said patch element that drive electric current at the patch elements to radiate the radio frequency signals;

applying the respective signals by the feed network to at least two said patch elements, wherein the respective signals define a predetermined phase shift with respect to each other that is fixed;

providing a radio frequency transmitter that drives the antenna to emit the radio frequency signals into the first area so that respective electric current patterns on the at least two patch elements are out of phase with each other; and

conveying items on the conveyor through the path of travel so that respective said radio frequency identification tags on said items are detected by a near field component of the radio frequency signals radiated by one of the patch elements without interference from the other patch elements.

16. The method as in claim 15, wherein the applying step comprises applying the respective signals by the feed network to each pair of adjacent said patch elements defining the predetermined phase shift with respect to each other.

17. The method as in claim 16, wherein the predetermined phase shift between each pair of said adjacent patch elements is the same.

18. The method as in claim 15, wherein the feed network applies the respective signals from a common source, and wherein the predetermined phase shift is defined by lengths of traces in the feed network between the common source and respective said patch elements.