Hybrid tag for radio frequency identification system

• US 10,090,889 B2
• Filed: 06/07/2017
• Issued: 10/02/2018
• Est. Priority Date: 03/31/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Friedman, Daniel J., Liu, Duixian, Sanduleanu, Mihai A.
• Primary Examiner(s): McNally, Kerri
• Assistant Examiner(s): Tran, Thang
• Application Number:
  US15/616,064
• Publication Number:
  US 20170272125A1
• Time in Patent Office: 482 Days
• Field of Search: 340 1034, 340101- 106, 3405721-5729
• 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: H04B 10/803 Free space interconnects, e.g. between circuit boards or chips
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

RFID (radio frequency identification) systems are provided in which tag and interrogator devices implement a hybrid framework for signaling including an optical transmitter/receiver system and an RF transmitter/receiver system. For instance, an RFID tag device includes: optical receiver circuitry configured to receive an optical signal having an embedded clock signal from an interrogator device, and convert the optical signal into an electrical signal comprising the embedded clock signal; clock extraction circuitry configured to extract the embedded clock signal from the electrical signal, and output the extracted clock signal as a clock signal for controlling clocking functions of the tag device; voltage regulator circuitry configured to generate a regulated supply voltage from the electrical signal, wherein the regulated supply voltage is utilized as a bias voltage for components of the tag device; and data transmitter circuitry configured to wirelessly transmit tag data to the interrogator device.

Claims

1. A tag device, comprising:

a substrate comprising a plurality of components integrally formed thereon, wherein the components comprise;

state machine control circuitry configured to control functions of the tag device;

a non-volatile memory configured to store tag data;

optical receiver circuitry configured to receive a pulsed optical signal having an embedded clock signal from an interrogator device, and convert the pulsed optical signal into an electrical signal which represents the embedded clock signal within the pulsed optical signal optically transmitted from the interrogator device;

clock extraction circuitry configured to extract the embedded clock signal from the electrical signal output from the optical receiver circuitry, and output the extracted clock signal as a clock signal for controlling clocking functions of the tag device; and

data transmitter circuitry;

wherein the clock signal is input to the state machine control circuitry to control a memory access operation of the non-volatile memory, wherein the memory access operation comprises reading out the stored tag data as a serial data bit stream that is serially clocked to the data transmitter circuitry using the clock signal;

wherein the data transmitter circuitry is configured to wirelessly transmit the tag data to the interrogator device;

wherein the data transmitter circuitry comprises;

a loop antenna; and

switching circuitry that is configured to change an impedance of the loop antenna in response to the serial data bit stream which comprises the tag data read out from the non-volatile memory.

2. The tag device of claim 1, wherein the optical receiver circuitry comprises one or more photodiodes that are configured to operate in a photovoltaic mode to convert photonic energy of the pulsed optical signal into a current.

3. The tag device of claim 2, wherein the one or more photodiodes are connected in a stacked configuration comprising a plurality of serially connected photodiode stages, wherein at least one photodiode stage comprises a plurality of parallel connected photodiodes.

4. The tag device of claim 1, wherein the loop antenna comprises a planar multi-loop antenna having a differential feed.

5. The tag device of claim 1, wherein one or more of the components of the tag device are disposed within an inner loop area of the loop antenna.

6. The tag device of claim 1, wherein the substrate comprises a flexible substrate.

7. The tag device of claim 1, wherein each of a length, width, and thickness dimension of the tag device is about 75 microns or less.

8. An interrogator device, comprising:

control circuitry configured to control functions of the interrogator device;

optical transmitter circuitry configured to generate and transmit a pulsed optical signal having an embedded clock signal to a tag device, wherein the embedded clock signal within the pulsed optical signal is recoverable by the tag device to control clocking functions of the tag device;

an antenna; and

receiver circuitry configured to (i) apply an unmodulated radio frequency (RF) carrier signal to the antenna of the interrogator device to couple RF power of the unmodulated RF carrier signal to an antenna of the tag device, (ii) detect changes in amplitude of an amplitude modulated backscattered RF carrier signal which is reflected from the antenna of the tag device and captured on the antenna of the interrogator device, and (iii) recover a serial data bit stream comprising tag data transmitted from the tag device, based on the detected changes in said amplitude of the amplitude modulated backscattered RF carrier signal captured on the antenna of the interrogator device, the amplitude modulated backscattered RF carrier signal being generated by modulating an impedance of the antenna of the tag device based on a logic level of data bits of the serial data bit stream.

9. The interrogator device of claim 8, wherein the optical transmitter circuitry comprises:

a laser-emitting device; and

driver circuitry configured to control modulation of the laser emitting laser-emitting device and cause the laser emitting device to generate and output the pulsed optical laser signal having the embedded clock signal.

10. The interrogator device of claim 9, wherein the pulsed optical laser signal comprises a duty cycle of approximately 50%.

11. The interrogator device of claim 9, wherein the laser-emitting device comprises a vertical-cavity surface-emitting laser diode.

12. A system, comprising:

a tag device; and

an interrogator device;

wherein the interrogator device comprises;

control circuitry configured to control functions of the interrogator device;

optical transmitter circuitry configured to generate and transmit a pulsed optical signal having an embedded clock signal to the tag device;

an antenna; and

receiver circuitry configured to (i) apply an unmodulated radio frequency (RF) carrier signal to the antenna of the interrogator device to couple RF power of the unmodulated RF carrier signal to the loop antenna of the tag device, (ii) detect changes in amplitude of an amplitude modulated backscattered RF carrier signal which is reflected from the loop antenna of the tag device and captured on the antenna of the interrogator device, and (iii) recover a serial data bit stream comprising tag data transmitted from the tag device, based on the detected changes in said amplitude of the amplitude modulated backscattered RF carrier signal captured on the antenna of the interrogator device, the amplitude modulated backscattered RF carrier signal being generated by changing an impedance of the loop antenna of the tag device based on a logic level of data bits of the serial data bit stream; and

wherein the tag device comprises;

a substrate comprising a plurality of components integrally formed thereon, wherein the components comprise;

state machine control circuitry configured to control functions of the tag device;

a non-volatile memory configured to store the tag data;

optical receiver circuitry configured to receive the pulsed optical signal having the embedded clock signal from the interrogator device, and convert the pulsed optical signal into an electrical signal which represents the embedded clock signal within the pulsed optical signal;

clock extraction circuitry configured to extract the embedded clock signal from the electrical signal output from the optical receiver circuitry, and output the extracted clock signal as a clock signal for controlling clocking functions of the tag device;

data transmitter circuitry configured to wirelessly transmit tag data to the interrogator device;

wherein the clock signal is input to the state machine control circuitry to control a memory access operation of the non-volatile memory, wherein the memory access operation comprises reading out the stored tag data as the serial data bit stream that is serially clocked to the data transmitter circuitry using the clock signal; and

wherein the data transmitter circuitry comprises switching circuitry that is configured to change the impedance of the loop antenna of the tag device in response to the serial data bit stream;

wherein changing the impedance of the loop antenna modulates RF power on the loop antenna and causes modulated RF power encoded with the serial data bit stream to be reflected back to the antenna of the interrogator device.

13. The system of claim 12, wherein the pulsed optical laser signal comprises a duty cycle of approximately 50%.

14. The system of claim 12, wherein the loop antenna of the tag device comprises a planar multi-loop antenna having a differential feed.

15. The system of claim 12, wherein one or more of the components of the tag device are disposed within an inner loop area of the loop antenna.

16. The system of claim 12, wherein the substrate of the tag device comprises a flexible substrate.

17. The system of claim 12, wherein each of a length, width, and thickness dimension of the tag device is about 75 microns or less.

18. The system of claim 12, wherein the optical receiver circuitry of the tag device comprises one or more photodiodes that are configured to operate in a photovoltaic mode to convert photonic energy of the pulsed optical signal into a current, and wherein the one or more photodiodes are connected in a stacked configuration comprising a plurality of serially connected photodiode stages, wherein at least one photodiode stage comprises a plurality of parallel connected photodiodes.