Piezo-electric tag

• US 6,894,616 B1
• Filed: 07/31/2000
• Issued: 05/17/2005
• Est. Priority Date: 07/29/1999
• Status: Expired

• Current Assignee: Liberty Patents LLC
• Original Assignee: Mineral Lassen LLC (Intellectual Ventures LLC)
• Inventors: Forster, Ian J
• Primary Examiner(s): Tweel, Jr., John
• Assistant Examiner(s): Savoy, D
• Application Number:
  US10/048,108
• Time in Patent Office: 1,751 Days
• Field of Search: 340/572.1, 340/10.34, 330/79, 330/165, 330/166, 330/167, 330/168, 330/169, 330/170, 330/171, 330/188, 330/190, 330/195, 342/30, 235/491, 235/492, 310/310, 310/311, 310/313.R
• US Class Current: 340/572.1
• CPC Class Codes: G06K 19/067 Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
• CPC Class Codes: G06K 19/0675 the resonating marks being of the surface acoustic wave [SAW] kind SAW devices per se H03H9/64
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: H10N 30/40 with electrical input and electrical output, e.g. functioning as transformers
• CPC Class Codes: H10N 30/804 for piezoelectric transformers

Abstract

A piezo-electric tag in the form of a card has a first dipole antenna, a first rectification circuit, a piezo-electric transformer, a second rectification circuit, and a transponder circuit. In operation, the antenna receives incoming radiation and generates a corresponding signal which propagates to the first circuit which demodulates and filters it to generate a signal which is applied to the transformer to excite it. The transformer increases the voltage amplitude of the signal by generating a relatively higher voltage amplitude signal which is used in the tag to generate a signal for supplying power to the transponder. The transformer provides voltage magnitude enhancement to generate potentials suitable for operating active electronic circuits incorporated into the tag. The tag can be personnel wearable and even adapted for permanent inclusion into biological systems.

Claims

1. A piezo-electric tag, comprising:

a) receiving means for receiving input radiation and generating a corresponding received signal;

b) piezo-electric vibrating means for increasing voltage magnitude of the received signal to generate a supply potential; and

c) electronic circuit means powerable by the supply potential.

2. The tag according to claim 1, wherein the vibrating means comprises a piezo-electric transformer incorporating mutually vibrationally coupled primary and secondary regions, the transformer being operable to be excited into vibration by the received signal at the primary region and to generate a corresponding output signal at the secondary region for use in generating the supply potential.

3. A tag according to claim 1, wherein the vibrating means comprises a piezo-electric bi-morph operable to be excited into vibration by the received signal and to generate a corresponding output signal for use in generating the supply potential.

4. The tag according to claim 1, wherein the vibrating means comprises a silicon micromachined device comprising an array of resonant elements, each element incorporating an associated piezo-electric transducer operable to generate an element signal in response to vibration of its associated element, the transducers being connected in series to add their element signals to provide an overall output from which the supply potential is generated, and driving means operable to be driven by the received signal for stimulating the elements into vibration and thereby generating the supply potential.

5. The tag according to claim 4, wherein the resonant elements are operable at resonance to generate the supply potential.

6. The tag according to claim 4, wherein the resonant elements are housed in an evacuated environment for increasing their resonance Q factor.

7. The tag according to claim 1 wherein the receiving means incorporates demodulating means for demodulating modulation components present in the received radiation to generate the received signal.

8. The tag according to claim 7, wherein the demodulating means incorporates zero-bias Schottky diodes for demodulating the received radiation to generate the received signal.

9. The tag according to claim 7, wherein the demodulating means incorporates transistors operable as synchronous demodulators for demodulating the received radiation to generate the received signal.

10. The tag according to claim 1, wherein the circuit means is operable to function in a class C mode for reducing tag power consumption.

11. The tag according to claim 1, wherein the receiving means incorporates first and second antennas for generating the received signal for exciting the vibrating means, the first antenna being adapted to respond to microwave radiation, and the second antenna being adapted to respond to radiation having a carrier frequency corresponding to a resonant frequency of the vibrating means.

12. The tag according to claim 1, wherein the receiving means incorporates at least one of a metallic film dipole antenna, a loop antenna and a patch antenna for at least one of receiving and emitting radiation.

13. The tag according to claim 1, wherein the circuit means comprises responding means for emitting output radiation from the tag, the responding means being powerable by the supply potential.

14. The tag according to claim 13, wherein the vibrating means is operable to recover a clock component of Manchester bi-phase encoded radiation received at the tag, and wherein the responding means is operable to use the clock component to demodulate the encoded radiation to generate corresponding demodulated data for use in the tag.

15. The tag according to claim 13, wherein the tag incorporates two antennas, one antenna for use in generating the received signal, and the other antenna incorporated into the responding means for at least one of emitting and receiving radiation.

16. The tag according to claim 13, wherein the antennas are conductive metallic film dipole antennas.

17. The tag according to claim 1, the tag having a form of a block.

18. The tag according to claim 1, the tag having a form of a planar card.

19. The tag according to claim 18, wherein the card incorporates recesses for accommodating the receiving means, the vibrating means and the responding means.

20. The tag according to claim 13, wherein the responding means is a transponder operable to receive input radiation to the tag and emit output radiation in response from the tag.

21. The tag according to claim 20, wherein the transponder is operable to modulate the output radiation with a signature code by which the tag is individually identified.

22. The tag according to claim 20, wherein the transponder incorporates a reflection amplifier for amplifying the input radiation to generate the output radiation.

23. The tag according to claim 20, wherein the transponder is operable in a pseudo-continuous mode and incorporates a delay line for delaying the output radiation relative to the input radiation, thereby counteracting spontaneous oscillation from arising within the transponder from feedback therein.

24. The tag according to claim 1, and a metallic earthing plane for providing a common signal earth for the tag.

25. The tag according to claim 1, and means for implantation into a biological system and operable for at least one of monitoring and stimulating the biological system.