Wearable Authentication Device

Abstract

Conventional Near Field Communication (NFC) authentication devices sometimes waste their users' time by requiring users to repeatedly reorient the devices to an NFC reader to complete authentication. To reduce the need for this reorientation, the present inventors, devised, among other things, an authentication assembly including two or more antennas configured for connection to a single NFC-tag circuit. In some embodiments, the assembly is built into an adjustable ring that can authenticate a user to an NFC-equipped electronic device, for example a smart phone, associated with the ring. In this configuration, each of the antennas generate a magnetic field generally perpendicular to an outer surface of the ring when excited with an appropriate signal, providing the ring with multiple options for establishing an inductive coupling to an NFC sensor in the electronic device without requiring the user to reorient the ring.

What is claimed is: 
     
         1 . An assembly for a wearable authentication device, the assembly comprising:
 a substrate having a substrate surface;   first and second contact nodes for connection to an NFC tag component; and   an antenna conductor having first and second terminal nodes coupled to the first and second contact nodes, the antenna conductor including at least first and second inductive coils coupled between the first and second terminal nodes and supported by a corresponding portion of the surface, each coil configured to generate a magnetic field generally transverse to its corresponding portion of the surface in response to a compatible NFC excitation signal.   
     
     
         2 . The assembly of  claim 1 , wherein each of the inductive coils is configured as a planar coil. 
     
     
         3 . The assembly of  claim 1 , wherein the first and second inductive coils are coupled in series between the first and second contact nodes. 
     
     
         4 . The assembly of  claim 1 , wherein each coil is configured to generate a magnetic field generally perpendicular to its corresponding portion of the surface in response to a compatible NFC excitation signal. 
     
     
         5 . The assembly of  claim 1 , further comprising an NFC tag circuit coupled to the first and second contact nodes. 
     
     
         6 . The assembly of  claim 5 , wherein the NFC tag circuit is a passive NFC tag circuit. 
     
     
         7 . The assembly of  claim 1 , wherein the substrate comprises:
 an insulative layer containing the antenna conductor;   a base layer for contacting the skin of a user; and   a ferrite layer between the insulative layer and the base layer.   
     
     
         8 . The assembly of  claim 1 , wherein the substrate is configured as a ring-like structure. 
     
     
         9 . The assembly of  claim 8 , wherein the ring-like structure includes a gap defined by first and second ends of the substrate, with the gap being adjustable to change an effective circumference of the ring-like structure. 
     
     
         10 . A system comprising:
 an electronic device having an NFC sensor, with the NFC sensor having a memory storing a representation of an authentication code; and   a wearable authentication device including:
 an NFC tag circuit including a memory storing a representation of the authentication code, and first and second contact nodes; and 
 an assembly including: 
 a substrate having a substrate surface; 
 first and second contact nodes for connection to an NFC tag component; and 
 an antenna conductor having first and second terminal nodes coupled to the first and second contact nodes, the antenna conductor including at least first and second inductive coils coupled between the first and second terminal nodes and supported by a corresponding portion of the surface, each coil configured to generate a magnetic field generally transverse to its corresponding portion of the surface in response to a compatible NFC excitation signal. 
   
     
     
         11 . The system of  claim 10 , wherein each of the inductive coils is configured as a planar coil and coupled in series between the first and second contact nodes. 
     
     
         12 . The system of  claim 10 , wherein each coil is configured to generate a magnetic field generally perpendicular to its corresponding portion of the surface in response to the NFC excitation signal. 
     
     
         13 . The system of  claim 10 , wherein the NFC tag circuit is a passive NFC tag circuit. 
     
     
         14 . The system of  claim 10 , wherein the substrate comprises:
 an insulative layer containing the antenna conductor;   a base layer for contacting the skin of a user; and   a ferrite layer between the insulative layer and the base layer.   
     
     
         15 . The system of  claim 14 , wherein the substrate is configured as a ring-like structure. 
     
     
         16 . The system of  claim 8 , wherein the ring-like structure includes a gap defined by first and second ends of the substrate, with the gap being adjustable to change an effective circumference of the ring-like structure. 
     
     
         17 . A wearable authentication device comprising:
 an integrated NFC tag circuit having first and second contact nodes; and   first and second planar coil antennas electrically coupled to the first and second contact pads, with each coil antenna configured to generate, in response to an excitation signal from the tag circuit, a magnetic field generally transverse to a plane defined by the coil antenna.   
     
     
         18 . The device of  claim 17 , wherein the magnetic field is substantially perpendicular to the plane defined by the coil antenna. 
     
     
         19 . The device of  claim 17 , wherein the first and second coil antennas are coupled in series between the first and second contact nodes. 
     
     
         20 . The device of  claim 23 , further comprising a substrate configured as a ring-like structure, with the first and second coil antennas attached to the substrate, opposite each other. 
     
     
         21 . A method comprising:
 exciting a first NFC antenna element with an interrogation signal; and   driving, in response to the interrogation signal, the first NFC antenna element and a second NFC antenna to provide respective first and second responsive magnetic fields, with the first and second NFC antenna elements coupled to an NFC driver circuit.   
     
     
         22 . The method of  claim 21 , wherein the first and second antenna elements are coupled in series between first and second contact nodes of an NFC tag circuit. 
     
     
         23 . The method of  claim 21 , wherein the first and second antenna elements are configured as respective first and second flat spirals and supported by a common substrate. 
     
     
         24 . A kit comprising:
 an electronic device having an NFC sensor, with the NFC sensor having a first memory storing for a representation of an authentication code; and   a wearable authentication device including:
 an NFC tag circuit including a second memory for storing a representation of the authentication code, and first and second contact nodes; and 
 an assembly including: 
 a substrate having a substrate surface; 
 first and second contact nodes coupled to the NFC tag circuit; and 
 an antenna conductor having first and second terminal nodes coupled to the first and second contact nodes of the NFC tag circuit, the antenna conductor including at least first and second inductive coils coupled between the first and second terminal nodes and supported by a corresponding portion of the surface, each coil configured to generate a magnetic field generally perpendicular to its corresponding portion of the surface in response to an NFC excitation signal generated by the electronic device. 
   
     
     
         25 . The kit of  claim 24 , wherein each of the inductive coils is configured as a planar coil and coupled in series between the first and second contact nodes. 
     
     
         26 . The kit of  claim 24 , wherein the substrate is configured as a ring-like structure having an adjustable effective circumference and comprising:
 an insulative layer containing the antenna conductor;   a base layer for contacting the skin of a user; and   a ferrite layer between the insulative layer and the base layer.   
     
     
         27 . The kit of  claim 24 , wherein the electronic device includes means for programming the first memory and the second memory to include matching authentication codes.