Method and apparatus for testing RFID devices

• US 7,522,055 B2
• Filed: 10/30/2007
• Issued: 04/21/2009
• Est. Priority Date: 05/11/2005
• Status: Expired due to Fees

• Current Assignee: RUIZHANG TECHNOLOGY LIMITED COMPANY
• Original Assignee: Alien Technology Corporation
• Inventors: Carrender, Curtis Lee, Hadley, Mark A.
• Primary Examiner(s): PHAM, TOAN NGOC
• Application Number:
  US11/929,632
• Publication Number:
  US 20080117051A1
• Time in Patent Office: 539 Days
• Field of Search: 340/572.1, 340/572.4, 340/572.7, 235/438, 235/437, 235/492
• US Class Current: 340/572.1
• CPC Class Codes: G01R 31/2822 of microwave or radiofrequency circuits of attenuation, gain, e.g. using network analyzers G01R27/28
• CPC Class Codes: G01R 31/31905 Interface with the device under test [DUT], e.g. arrangements between the test head and the DUT, mechanical aspects, fixture
• CPC Class Codes: G01R 31/31926 Routing signals to or from the device under test [DUT], e.g. switch matrix, pin multiplexing
• CPC Class Codes: G06K 7/0095 Testing the sensing arrangement, e.g. testing if a magnetic card reader, bar code reader, RFID interrogator or smart card reader functions properly testing of electrical circuits G01R31/28
• CPC Class Codes: H01L 2924/15153 the die mounting substrate comprising a recess for hosting the device

Abstract

A method and apparatus for testing RFID straps. Arrays of RFID straps in a roll-to-roll process are coupled to an array of test elements. RF programming and interrogation signals are frequency and time multiplexed to the RFID array. Return signals are detected to determine sensitivity and programmability parameters of the RFID straps.

Claims

1. A method for testing a column of radio frequency identification (RFID) straps,

wherein an RFID strap in the column of RFID straps comprises:

an RFID chip on a continuous web material; and

a pair of electrical contacts on the continuous web material coupled to the RFID chip,

the method comprising;

transmitting a test signal from an RFID tester to the electrical contacts of at least one strap of the column of straps on the continuous web material, the column being oriented parallel to a transport direction of the continuous web material and having at least 35 straps;

detecting for a return signal from the at least one strap, the return signal having less power than the test signal; and

if the detecting for the return signal indicates the at least one strap is defective, then marking with a mark on an electrical contact of the at least one strap, wherein a frequency of the test signal is between 902 MHz and 928 MHz.

2. The method of claim 1 wherein the RFID tester is capacitively coupled to the electrical contacts of the at least one strap.

3. The method of claim 1 wherein the RFID tester directly contacts the at least one strap during the transmitting.

4. The method of claim 1 wherein the electrical contact is configured for attachment to an antenna.

5. The method of claim 4 wherein the electrical contact is screen printed and comprises silver.

6. The method of claim 4 wherein the electrical contact comprises copper.

7. The method of claim 1 wherein the at least one strap further comprises:

a tape layer between the electrical contact and an RFID chip; and

a conductive material through at least one hole in the tape layer to electrically connect the electrical contact and the RFID chip.

8. The method of claim 1 wherein the mark is formed by a laser.

9. A method for testing a column of radio frequency identification (RFID) straps,

wherein an RFID strap in the column of RFID straps comprises:

an RFID chip on a web material; and

a pair of electrical contacts on the web material coupled to the RFID chip,

the method comprising;

transmitting by a transmitting means a test signal from an RFID tester to at least one strap of the column of straps on the web material, the column being oriented parallel to a transport direction of the web material and having at least 35 straps;

detecting by a detecting means a return signal from the at least one strap, the return signal having less power than the test signal; and

if the detecting for the return signal indicates the at least one strap is defective, then marking with a mark on an electrical contact of the at least one strap by a marking means.

10. The method of claim 9 wherein the RFID tester is capacitively coupled to the electrical contacts of the at least one strap.

11. The method of claim 9 wherein the RFID tester directly contacts the at least one strap during the transmitting.

12. The method of claim 9 wherein the electrical contact is configured for attachment to an antenna.

13. The method of claim 12 wherein the electrical contact is screen printed and comprises silver.

14. A method for testing radio frequency identification (RFID) straps,

wherein an RFID strap comprises:

an RFID chip on a web material; and

a pair of electrical contacts on the web material coupled to the RFID chip,

the method comprising;

transmitting a test signal from an RFID tester to at least one strap of the column of straps on the web material, the column being oriented parallel to a transport direction of the web material and having at least 35 straps;

detecting for a return signal from the at least one strap, the return signal having less power than the test signal; and

if the detecting for the return signal indicates the at least one strap is defective, then electronically storing the location of the at least one strap,

wherein a frequency of the test signal is between 902 MHz and 928 MHz.

15. The method of claim 14 wherein the electronically storing writes the location into a database.

16. The method of claim 14 wherein the electronically storing writes the location into non-volatile memory.

17. The method of claim 14 wherein the RFID tester is capacitively coupled to the at least one strap.

18. The method of claim 14 wherein the RFID tester directly contacts the at least one strap during the transmitting.

19. The method of claim 14 wherein the electrical contact is configured for attachment to an antenna.

20. The method of claim 19 wherein the electrical contact is screen printed and comprises silver.

21. An apparatus configured to test for defective RFID devices in a column of RFID devices on a continuous web material, each of the RFID devices including one integrated circuit attached to a substrate, the apparatus comprising:

a transmitter configured to transmit a test signal to at least one of the RFID devices in the column of RFID devices, the column being oriented parallel to a transport direction of the continuous web material and having at least 35 RFID devices in the column and wherein a frequency of the test signal is between 902 MHz and 928 MHz;

a receiver configured to receive a return signal from the at least one of the RFID devices, the return signal having less power than the test signal;

a processor, coupled to the receiver, the processor being configured to determine if the at least one of the RFID devices is defective; and

a marking device, coupled to the processor, the marking device being configured to place a mark on an electrical contact of each of the plurality of RFID devices that is determined to be defective.

22. The apparatus as in claim 21 wherein each of the RFID devices comprises an RFID strap and wherein the substrate is disposed in a roll.

23. The apparatus as in claim 22 wherein the substrate is a flexible plastic substrate.

24. The apparatus as in claim 23 wherein the electrical contact is configured for attachment to an antenna.

25. The apparatus as in claim 24 wherein the electrical contact is larger in area than a contact on the integrated circuit.