RFID tag temperature adaptation

An RFID system and tag, and a method for identifying objects using an RFID system are disclosed. In an embodiment, an RFID tag comprises a microchip for storing an identification sequence, a tag antenna coupled with the microchip for receiving and transmitting the RF signal; and a ferrous metal portion disposed near the IC and the tag antenna. The ferrous metal portion is sensitive to, and heats up when subjected to, magnetic induction. The heat of the ferrous metal is propagated to the RFID tag such that the tag reaches its operating temperature more quickly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of European Patent Application No. 11306387.9 filed 26 Oct. 2011, which is hereby incorporated herein.

BACKGROUND OF THE INVENTION

The disclosure relates generally to identification of biological samples, and more particularly, to the use of a radio frequency identification system for identifying containers which may contain biological samples therein.

Radio frequency identification, or RFID, is a generic term for technologies that use radio waves to identify objects, such as, e.g., containers for biological samples. RFID tags may store a series number or other identifier that identifies the container or the contents thereof, on a microchip attached to an antenna. Collectively, the microchip and antenna are referred to as an RFID tag or RFID transponder.

RFID tags can be categorized as active, semi-passive, and passive RFID tags, which can be distinguished from one another on the basis of power supply. Passive RFID tags are battery-free, and react to a specific, reader-produced inductively coupled or radiated electromagnetic field by delivering a data modulated RF response. Passive RFID tags draw power from the reader, which emits electromagnetic waves that induce a current in the antenna of the RFID tag. The voltage generated may be stored in a capacitor in the RFID tag. The RFID tag then transmits data stored in the RFID tag microchip back to the RFID tag reader, e.g., by switching low resistance across the antenna coil, and the capacitor discharges. The change in voltage across the RFID tag antenna generates an RF signal referred to as backscattering. When the signal is received at the RFID tag reader, the reader removes or demodulates the carrier RF signal, and the resulting digital signal can be decoded.

Active RFID tags, in contrast, include a transmitter for sending information to the reader rather than merely reflecting a signal from the reader as the passive RFID tag does. In order to provide power for the signal transmission, active RFID tags include a power source, such as a long-life battery, which provides power to the circuit of the microchip and to the antenna to broadcast a signal to a reader. Semi-passive RFID tags are a hybrid of the two. They include batteries, but they communicate using the same backscatter technique as passive RFID tags, using battery power only to run the circuitry of the microchip, and in some cases an onboard sensor. Semi-passive RFID tags have a longer read range than passive RFID tags because all of the energy gathered from the reader can be reflected back to the reader. Active and semi-passive RFID tags are typically used to track high value goods that need to be scanned over long ranges, and are typically more expensive to produce than passive RFID tags. Passive RFID tags, in contrast, may use ultra-high frequency RF waves, and may have a shorter range such as, e.g., less than 20 feet.

Biological samples are typically stored in containers or vials, and may be kept at conservation temperatures of about −170° C. (−274° F.). These vials may be equipped with RFID tags affixed to the vials using an adhesive for identifying the samples. In many cases, passive RFID tags are used in such applications. Before selecting a sample for use or testing, the RFID tag must be read in order to identify the requested sample. Before they can be read, however, conventional RFID tags must be warmed to a temperature of about −80° C. (−112° F.), which may take upwards of 20 minutes. This may cause the tagged biological sample to reach and sustain higher temperatures than may be desirable to maintain the sample's integrity.

Examples of biological samples which may be stored in this manner may include, for example, samples collected during clinical trials of pharmaceuticals, research samples in labs, samples archived in hospitals, forensic samples from crimes or disasters, samples maintained at the Center for Disease Control (CDC), and samples used for in vitro fertilization.

BRIEF DESCRIPTION OF THE INVENTION

A first aspect of the disclosure provides an RFID tag or transponder comprising: a microchip for storing an identification sequence; a tag antenna coupled with the microchip for receiving and transmitting an RF signal; and a ferrous metal portion disposed about the tag antenna, wherein the ferrous metal portion is sensitive to magnetic induction.

A second aspect of the disclosure provides an RFID system comprising an RFID tag reader and an RFID tag. The RFID tag reader includes a transceiver for generating an RF signal; a reader antenna coupled to the transceiver for transmitting the RF signal; and a magnetic field generator. The RFID tag includes a microchip for storing an identification sequence; a tag antenna coupled with the microchip for receiving and transmitting the RF signal; and a ferrous metal portion disposed about the tag antenna, wherein the ferrous metal portion is sensitive to magnetic induction.

A third aspect of the disclosure provides a method for identifying an object. The method includes, using an RFID tag reader, generating a magnetic field, generating an RF signal, and transmitting the RF signal; exposing an RFID tag to the RF signal and the magnetic field. The RFID tag includes a ferrous metal portion. The method further includes, with the magnetic field, inducing a current in the ferrous metal portion, raising a temperature of the ferrous metal portion; and on the RFID tag, converting the RF signal to a current, and transmitting data stored on a microchip on the RFID tag to the RFID tag reader.

These and other aspects, advantages and salient features of the invention will become apparent from the following detailed description, which, when taken in conjunction with the annexed drawings, where like parts are designated by like reference characters throughout the drawings, disclose embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, aspects of the invention provide an RFID system including an RFID tag, and an RFID reader, as well as a method for identifying an object using the RFID tag and RFID reader.

FIGS. 1-3show aspects of an RFID tag100in accordance with an embodiment of the invention.FIG. 1shows an RFID tag100including a microchip102including an integrated circuit (IC), which serves to modulate and de-modulate a radio-frequency (RF) signal, and a tag antenna104coupled with the microchip102for receiving and transmitting the RF signal. RFID tag100may further include packaging106which may cover or provide structural support for RFID tag100, and may be used to affix RFID tag100to container112, discussed further below. Packaging106may be, in some embodiments, plastic. A ferrous metal portion108, shown inFIG. 2, may further be affixed to RFID tag100as shown inFIG. 3, resulting in an RFID tag110that includes a ferrous metal portion108. Ferrous metal portion108is sensitive to magnetic induction, and may be a ferrous metal sheet in some embodiments. Ferrous metal portion108may be Fe in some embodiments. Ferrous metal portion may be disposed directly adjacent to microchip102and tag antenna104, or may be separated from microchip102and tag antenna104by a portion of packaging106.

As shown inFIG. 4, RFID tag110may be adhered to a container112for use in identifying container112or the contents thereof. Container112may be, e.g., a vial, or other type of container. In one embodiment, container112may contain a biological sample. Container112, and the biological sample contained therein, may be stored in a cryogenic, low temperature environment, and may be stored at a temperature of about −170° C.

As further shown inFIG. 4, RFID system10further includes an RFID tag reader200. RFID tag reader200may include transceiver204for generating an RF signal, as well as reader antenna206coupled to transceiver204for transmitting RF signal202. RFID tag reader200further includes a magnetic field generator208for generating magnetic induction field including waves210. When RFID tag110is passed within range of magnetic induction waves210, magnetic induction waves210induce an eddy current in ferrous metal portion108. Resistance to these eddy currents causes the temperature of ferrous metal portion108to rise. Because ferrous metal portion108is disposed either directly adjacent or near microchip102and tag antenna104, when ferrous metal portion108is warmed, the heat of ferrous metal portion108is propagated to RFID tag110such that RFID tag110including tag antenna104reaches its operating temperature quickly. This keeps the contents of container112, e.g., a biological sample, at a lower temperature, thereby minimizing the cold chain impact. Due to the relatively small size of RFID tag110and ferrous metal portion108, the temperature of the sample contained in container112is not changed appreciably. Thus, RFID tag110can be warmed to allow for reading by RFID tag reader200without significantly raising the temperature of the sample contained in container112or meaningfully impacting its integrity. In some embodiments, when subjected to magnetic induction, ferrous metal portion108may cause RFID tag110to be warmed to a temperature of about −80° C. to about −70° C., a temperature at which RFID tag reader200may read RFID tag110. When RFID tag110reaches a temperature at which it can be read, i.e., tag antenna104(FIG. 3) begins responding or reflecting212the signal transmitted by reader antenna206back to RFID tag reader200, magnetic field generator208ceases generating magnetic induction waves210. This avoids ferrous metal portion108becoming any warmer than necessary to allow reading of RFID tag110.

As shown inFIG. 5, a method is also provided for identifying an object, which in some embodiments may be a container112having a biological sample therein. In step S1, using RFID tag reader200, which includes magnetic field generator208, a magnetic field210is generated. In step S2, using transceiver204, RF signal202is generated, and using reader antenna206, RF signal202is transmitted from RFID tag reader200. In step S3, RFID tag110is exposed to RF signal202and magnetic field210. RFID tag110includes a ferrous metal portion108as described above. In step S4, magnetic field210induces a current in ferrous metal portion108, and causes the temperature of RFID tag110to rise. In step S5, RFID tag may start to respond to the RFID signal generated and transmitted in step S2. If it does not respond, steps S3and S4are repeated until RFID tag110begins to respond. A response from RFID tag110typically includes a transmission from tag antenna104that reflects RF signal202back to reader antenna206and contains the identification information stored in microchip102. In some embodiments, in step S6, once RFID tag110begins responding, RFID tag reader ceases generating magnetic induction waves210to avoid further warming RFID tag110and possibly container112. In step S7, RFID tag reader200reads or interprets the signal received from RFID tag110, including removing or demodulating the carrier RF signal, and the resulting digital signal can be decoded. In further embodiments, ferrous metal portion108may be used affixed to any other type of electronic device not limited to RFID tag110, such as, e.g., a probe, which needs to be warmed up quickly in order to become operational.

As used herein, the terms “first,” “second,” and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., includes the degree of error associated with measurement of the particular quantity). The suffix “(s)” as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including one or more of that term (e.g., the metal(s) includes one or more metals). Ranges disclosed herein are inclusive and independently combinable (e.g., ranges of “up to about −70° C., or, more specifically, about −80° C. to about −70° C.,” is inclusive of the endpoints and all intermediate values of the ranges of “about −80° C. to about −70° C.,” etc.).