RFID READER WITH AUTOMATIC NEAR/FAR FIELD INTERROGATION MODE SWITCHING, AND RELATED OPERATING METHODS

• US 20100127828A1
• Filed: 11/21/2008
• Published: 05/27/2010
• Est. Priority Date: 11/21/2008
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Duron, Mark, Connolly, Sean
• Granted Patent: US 8,305,192 B2
• Time in Patent Office: Days
• US Class Current: 340/10.100
• 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 7/10237 the reader and the record carrier being capable of selectively switching between reader and record carrier appearance, e.g. in near field communication [NFC] devices where the NFC device may function as an RFID reader or as an RFID tag
• CPC Class Codes: G06K 7/10386 the interrogation device being of the portable or hand-handheld type, e.g. incorporated in ubiquitous hand-held devices such as PDA or mobile phone, or in the form of a portable dedicated RFID reader

Abstract

A dual-mode RFID reader is capable of automatically switching from a far-field interrogation mode to a near-field interrogation mode upon the detection of certain operating or handling conditions. The RFID reader includes an RFID radio module configured to support a far-field interrogation mode and a near-field interrogation mode, an antenna arrangement coupled to the RFID radio module, and a mode-switch sensor architecture coupled to the RFID radio module. The mode-switch sensor architecture is configured to detect conditions indicative of near-field interrogation, and the RFID radio module automatically configures itself for operation in the near-field interrogation mode upon detection of such conditions.

Claims

1. A method of operating an RFID reader that can operate in a far-field interrogation mode and in a near-field interrogation mode, the method comprising:

processing a user-initiated interrogation trigger;

automatically configuring the RFID reader for operation in the near-field interrogation mode in response to the user-initiated interrogation trigger; and

interrogating an RFID tag while the RFID reader is in the near-field interrogation mode.

2. The method of claim 1, further comprising automatically configuring the RFID reader for operation in the far-field interrogation mode after interrogating the RFID tag.

3. The method of claim 1, further comprising:

receiving tag data from the RFID tag in response to the interrogating step; and

automatically configuring the RFID reader for operation in the far-field interrogation mode after receiving the tag data.

4. The method of claim 1, further comprising automatically configuring the RFID reader for operation in the far-field interrogation mode, after a predetermined time period measured from the user-initiated interrogation trigger.

5. The method of claim 1, further comprising automatically configuring the RFID reader for operation in the far-field interrogation mode, after a predetermined time period measured from the step of automatically configuring the RFID reader for operation in the near-field interrogation mode.

6. The method of claim 1, wherein the processing step processes user manipulation of a human-machine interface element.

7. The method of claim 6, wherein the processing step processes user manipulation of a human-machine interface element that is selected from a group consisting of a trigger mechanism, a switch, a button, a lever, a voice command processor, a touch screen, a touchpad, a keyboard, an optical sensor, a graphical pointing device, a VSWR sensor, and a motion sensor.

8. The method of claim 1, wherein:

the RFID reader has an interrogation range; and

automatically configuring the RFID reader for operation in the near-field interrogation mode comprises reducing the interrogation range to less than six inches.

9. A dual-mode RFID reader comprising:

an RFID radio module configured to support a far-field interrogation mode and a near-field interrogation mode;

an antenna arrangement coupled to the RFID radio module and configured to support the far-field interrogation mode and the near-field interrogation mode; and

a mode-switch sensor architecture coupled to the RFID radio module and configured to detect conditions indicative of near-field interrogation, wherein the RFID radio module automatically configures itself for operation in the near-field interrogation mode upon detection of the conditions.

10. The dual-mode RFID reader of claim 9, wherein the mode-switch sensor architecture comprises an RF signal analyzer associated with the RFID radio module, the RF signal analyzer being configured to analyze RF characteristics of signals received by the dual-mode RFID reader.

11. The dual-mode RFID reader of claim 10, wherein:

the RF signal analyzer analyzes standing wave ratio (SWR) measurements of signals received by the dual-mode RFID reader; and

the RFID radio module automatically configures itself for operation in the near-field interrogation mode in response to a VSWR measurement that exceeds a threshold value.

12. The dual-mode RFID reader of claim 9, wherein the mode-switch sensor architecture comprises an accelerometer configured to detect physical contact between a component of the dual-mode RFID reader and an RFID tag.

13. The dual-mode RFID reader of claim 12, wherein:

the antenna arrangement comprises an antenna element; and

the component is the antenna element.

14. The dual-mode RFID reader of claim 9, wherein:

the mode-switch sensor architecture comprises;

an optical sensor configured to capture image data within an interrogation field of the dual-mode RFID reader; and

an image processor that analyzes the image data; and

the RFID radio module automatically configures itself for operation in the near-field interrogation mode when the image processor detects an object in the interrogation field that is within close proximity to the dual-mode RFID reader.

15. The dual-mode RFID reader of claim 14, wherein the RFID radio module automatically configures itself for operation in the near-field interrogation mode when the image processor detects an object in the interrogation field that is out of focus.

16. A method of operating a mobile RFID reader that can operate in a far-field mode for concurrently interrogating a plurality of RFID tags and in a near-field mode for individually interrogating one RFID tag at a time, the method comprising:

detecting a condition that is indicative of a need to perform near-field interrogation;

automatically configuring the mobile RFID reader for operation in the near-field mode in response to detecting the condition; and

thereafter, interrogating an RFID tag while the mobile RFID reader is in the near-field mode.

17. The method of claim 16, further comprising automatically configuring the mobile RFID reader for operation in the far-field mode after successfully interrogating the RFID tag.

18. The method of claim 16, wherein the detecting step comprises:

measuring RF characteristics of signals received by the mobile RFID reader; and

indicating presence of the condition when the RF characteristics satisfy predetermined criteria.

19. The method of claim 16, wherein the detecting step comprises sensing physical contact between a component of the mobile RFID reader and an item associated with the RFID tag.

20. The method of claim 16, wherein the detecting step comprises:

capturing image data within an interrogation field of the mobile RFID reader;

processing the image data; and

indicating presence of the condition when the image data conveys an object in the interrogation field that is within close proximity to the mobile RFID reader.