Read-write processing apparatus and method for RFID tag

• US 7,421,249 B2
• Filed: 01/21/2005
• Issued: 09/02/2008
• Est. Priority Date: 01/27/2004
• Status: Active Grant

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Ozaki, Koyo, Ariyoshi, Tomonori, Sakacho, Koji
• Primary Examiner(s): Le; Lana N.
• Assistant Examiner(s): DAGLAWI, AMAR A
• Application Number:
  US11/040,619
• Publication Number:
  US 20050170784A1
• Time in Patent Office: 1,320 Days
• Field of Search: 455/67.13, 455/67.14, 455/67.7, 342/500, 340/10.1, 340/10.2, 340/10.3, 340/10.4, 340/10.5, 340/10.6, 340/500
• US Class Current: 455/67.13
• 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: H01Q 1/362 for broadside radiating helical antennas
• CPC Class Codes: H01Q 11/08 Helical antennas
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H04B 5/00 Near-field transmission systems, e.g. inductive or capacitive transmission systems
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A read-write processing apparatus communicates with an RFID tag provided with a semiconductor memory to exchange commands and responses through antenna coils. A condition under which only a carrier wave is transmitted is set prior to a communication with the RFID tag and a level from a reception signal obtained under this condition is extracted as noise level. The extracted noise level is displayed or outputted to an output host apparatus.

Claims

1. An apparatus for communicating with an RFID tag provided with a semiconductor memory to read and write data from and into said semiconductor memory, said apparatus comprising:

signal extracting means for comparing, while known data are being transmitted from said RFID tag in a communication process with said RFID tag, said known data and a base signal being received and thereby extracting a known data signal level corresponding to a period during which said RFID tag switches impedance periodically and another base signal level corresponding to another period during which impedance is not switched periodically;

calculating means for calculating the ratio or the difference between the levels of said known data signal and said base signal; and

reporting means for displaying or outputting result of calculation by said calculating means.

2. The apparatus of claim 1 further comprising communication control means for comparing a numerical value obtained by said calculating means with a specified threshold value and stopping said communication process when said numerical value changes so as to cross said threshold value.

3. The apparatus of claim 1 further comprising:

history data memory that stores history data on processes of each time; and

storing means for storing the result of calculation by said calculating means in said history data memory in correlation with data that indicate success and failure of communication with said RFID tag.

4. The apparatus of claim 2 further comprising:

history data memory that stores history data on processes of each time; and

storing means for storing the result of calculation by said calculating means in said history data memory in correlation with data that indicate success and failure of communication with said RFID tag.

5. A method of communicating with an RFID tag provided with a semiconductor memory to read and write data from and into said semiconductor memory, said method comprising the steps of:

comparing, while known data are being transmitted from said RFID tag in a communication process with said RFID tag, said known data and a base signal being received and thereby extracting a known data signal level corresponding to a period during which said RFID tag switches impedance periodically and another signal level corresponding to another base period during which impedance is not switched periodically;

calculating the ratio or the difference between the levels of said known data signal and said base signal; and

displaying or outputting result of calculation by said calculating means.