Reader arrangement for an electronic identification system having a plurality of reader heads for energizing transponders

• US 6,367,697 B1
• Filed: 08/28/1998
• Issued: 04/09/2002
• Est. Priority Date: 08/28/1997
• Status: Expired due to Term

• Current Assignee: Zebra Technologies Corporation
• Original Assignee: Supersensor Limited
• Inventors: Turner, Christopher Gordon Gervase, Kruger, Johan Dawid, Proctor, David Edwin
• Primary Examiner(s): Lee, Michael G.
• Assistant Examiner(s): LEE, DIANE I
• Application Number:
  US09/143,711
• Time in Patent Office: 1,320 Days
• Field of Search: 235/440, 235/436, 235/435, 340/10.1, 340/10.2, 340/10.3, 340/10.4, 340/10.5, 340/10.6
• US Class Current: 235/440
• 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 7/10039 interrogator driven, i.e. synchronous
• 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 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas

Abstract

A reader arrangement 22 for an electronic identification system includes a plurality of reader heads 22.1 to 22.4 for energizing transponders 28.1 to 28.n to be read, and a controller 29 therefor. The controller 29 switches activation of the reader heads in a multi-phase sequential pattern including a first phase for activating a first set 22.1 and 22.3 of the reader heads and at least one further phase for activating a further set 22.2 and 22.4 of the reader heads. The switching is such that a complete cycle plus at least the first phase of a subsequent cycle is completed within a time period not longer than a reset period of the transponders. The reset period is the period between removal of an energizing signal from a transponder and the transponder re-entering a normal operational mode.

Claims

1. A reader arrangement for an electronic identification system, the reader arrangement comprising a plurality of reader heads for energizing transponders to be read;

and control means for time multiplexing activation of the reader heads, the activation being multiplexed by switching activation of the reader heads in a multi-phase sequential pattern including a first phase for activating a first set of the reader heads and at least one further phase for activating at least one further set of said reader heads, so that a complete cycle plus at least the first phase of a subsequent cycle is completed within a time period not longer than a reset period of the transponders, the reset period being the period between removal of an energizing signal from a transponder and the transponder re-entering a normal operational mode.

2. A reader arrangement as claimed in claim 1 wherein the reader heads are arranged in an array.

3. A reader arrangement as claimed in claim 2 including a plurality of arrays of reader heads, the controller further being arranged to activate heads on either side of an interface between adjacent arrays in alternative phases of a cycle.

4. A reader arrangement as claimed in claim 1 wherein the reader heads in the first set and the reader heads in the at least one further set are arranged in alternating relationship.

5. A reader arrangement as claimed in claim 1 which is stationary.

6. A reader arrangement as claimed in claim 1 in which at least the reader heads are moveable past a volume including transponders to be read.

7. A reader arrangement as claimed in claim 1 including a central reader and wherein the control means includes fast switching means for connecting the reader heads to the reader.

8. A reader arrangement as claimed in claim 1 including at least one additional energizing means for energizing transponders, to prevent them from resetting to a normal operational mode of the transponder.

9. A reader arrangement as claimed in claim 1 wherein at least some of the heads are arranged such that central axes of radiation patterns associated with the heads extend transversely relative to one another.

10. A reader arrangement as claimed in claim 9 wherein the axes extend substantially perpendicular relative to one another.

11. A reader arrangement as claimed in claim 1 wherein each head includes an antenna adapted to transmit or receive signals the polarization of which is not limited to one plane.