US20060244600A1 - RFID tag - Google Patents

RFID tag Download PDF

Info

Publication number
US20060244600A1
US20060244600A1 US11/454,848 US45484806A US2006244600A1 US 20060244600 A1 US20060244600 A1 US 20060244600A1 US 45484806 A US45484806 A US 45484806A US 2006244600 A1 US2006244600 A1 US 2006244600A1
Authority
US
United States
Prior art keywords
circuit chip
antenna pattern
pad
rfid tag
end portion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US11/454,848
Inventor
Shunji Baba
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujitsu Ltd
Original Assignee
Fujitsu Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to JP2005081398A priority Critical patent/JP2006268090A/en
Priority to JP2005-081398 priority
Priority to US11/142,356 priority patent/US7298273B2/en
Application filed by Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to US11/454,848 priority patent/US20060244600A1/en
Assigned to FUJITSU LIMITED reassignment FUJITSU LIMITED ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BABA, SHUNJI
Publication of US20060244600A1 publication Critical patent/US20060244600A1/en
Application status is Abandoned legal-status Critical

Links

Images

Classifications

    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06KRECOGNITION OF DATA; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067Record 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
    • G06K19/07Record 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 with integrated circuit chips
    • G06K19/077Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06KRECOGNITION OF DATA; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067Record 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
    • G06K19/07Record 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 with integrated circuit chips
    • G06K19/077Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • G06K19/0775Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card arrangements for connecting the integrated circuit to the antenna
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00Details of, or arrangements associated with, antennas
    • H01Q1/12Supports; Mounting means
    • H01Q1/22Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/2208Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
    • H01Q1/2225Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10Bump connectors; Manufacturing methods related thereto
    • H01L2224/15Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10Bump connectors; Manufacturing methods related thereto
    • H01L2224/15Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
    • H01L2224/161Disposition
    • H01L2224/16151Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/16221Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/16225Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10Bump connectors; Manufacturing methods related thereto
    • H01L2224/15Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
    • H01L2224/161Disposition
    • H01L2224/16151Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/16221Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/16225Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • H01L2224/16227Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation the bump connector connecting to a bond pad of the item
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01055Cesium [Cs]
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/30Technical effects
    • H01L2924/301Electrical effects
    • H01L2924/3011Impedance
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/49002Electrical device making
    • Y10T29/49016Antenna or wave energy "plumbing" making
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/49002Electrical device making
    • Y10T29/49016Antenna or wave energy "plumbing" making
    • Y10T29/49018Antenna or wave energy "plumbing" making with other electrical component

Abstract

An RFID tag, including: a base; an antenna pattern that is provided on the base to form a communication antenna and has a tapered connection end portion which provides a connection terminal to the antenna; an electric conductor that is attached onto the connection end portion of the antenna pattern and is smaller than the connection end portion; and a circuit chip that is electrically connected to the antenna pattern via the electric conductor and performs radio communication by use of the antenna.

Description

    CROSS-REFERENCE TO RELATED APPLICATIONS
  • This application is related to and is a Continuation-In-Part, claiming priority to U.S. patent application entitled RFID Tag, having Ser. No. 11/142,356, by Fujitsu Limited, Kawasaki, Japan, filed on Jun. 2, 2005 and incorporated by reference herein. This application also claims the benefit of Japanese Patent Application No. 2005-081398, filed on Mar. 22, 2005, the disclosure of which is incorporated by reference herein.
  • BACKGROUND OF THE INVENTION
  • 1. Field of the Invention
  • The present invention relates to an RFID (Radio Frequency Identification) tag that performs information exchange with external equipment in a noncontact manner. Incidentally, among those skilled in the art related to the technical field of the present application, the “RFID tag” used in the specification of the present application may sometimes be called an “inlay for RFID tag” by regarding the “RFID tag” as an internal component member (inlay) for “RFID tag.” Or alternatively, in some cases, this “RFID tag” may be referred to as “a radio IC tag.” Also, a noncontact type IC card is included in this “RFID tag.”
  • 2. Description of the Related Art
  • In recent years, there have been proposed various RFID tags that perform information exchange with external equipment represented by a reader/writer in a noncontact manner by use of radio waves (refer to U.S. Pat. No. 6,239,703B1, for example). As one kind of this RFID tag, there has been proposed an RFID tag in which an antenna pattern for radio communication and an IC chip are mounted on a base sheet made of plastics or paper. A conceived mode of using an RFID tag of this type is such that the RFID tag is stuck to an article and the like and performs the identification of the article by exchanging information on the article with external equipment.
  • In such an RFID tag, a circuit chip and an antenna pattern are electrically connected together by pinching a micro electric conductor called a bump between the circuit chip and an end portion of the antenna pattern. The circuit chip is fixed to the above-described base sheet and on this occasion, the area between the circuit chip and the end portion of the antenna pattern except the part occupied by the bump is filled with an adhesive. As a result, it follows that a micro capacitor is formed, with the circuit chip and the end portion of the antenna pattern serving as electrodes. The capacity of such a capacitor that is unnecessary in terms of design is called a parasitic capacity, and a parasitic capacity in an RFID tag has an adverse effect as described below.
  • There is a type of RFID tag that obtains operating power of an internal circuit chip from external equipment, and in this type of RFID tag the power from external equipment is supplied to the circuit chip via an antenna pattern. When at this time, a parasitic capacity exists between the mutually electrically connected circuit chip and end portion of the antenna pattern, the input of operating power from the antenna pattern to the circuit chip is interfered with. As a result, there is a possibility that troubles such as the deterioration of the communication distance of the RFID tag due to insufficient operating power might be caused.
  • Therefore, there have been proposed techniques which involve providing, on the antenna pattern side, an adjustment pattern capable of changing an impedance by working such as etching, and adjusting an impedance including the above-described parasitic capacity between the antenna pattern and the circuit chip by working this adjustment pattern (refer to U.S. Pat. No. 6,535,175B2, for example).
  • However, such adjustment work has the problem that productivity is lowered thereby.
  • Hence, measures against the above-described parasitic capacity in an RFID tag often involve predicting the parasitic capacity and providing, on the antenna pattern side, a pattern which generates an inductance which cancels out the parasitic capacity by a circuital resonance.
  • The above-described prediction of a parasitic capacity in an RFID tag is performed on the basis of the area of a portion in which the circuit chip and the end portion of the antenna pattern overlap each other, with the above-described bump pinched between the two, (an overlapping portion).
  • However, there are variations in the positional relationship between the above-described circuit chip and the antenna pattern during the manufacture of an RFID tag, and it is difficult to predict a parasitic capacity in a stable manner. Furthermore, even when a predicted parasitic capacity is determined beyond the limits of reason and an inductance is found on the basis of the parasitic capacity, in a case where an actual parasitic capacity should differ from the predicted parasitic capacity, it becomes impossible to ensure matching between the actual parasitic capacity and the impedance and the above-described resonance does not occur any more. As a result, the parasitic capacity is not canceled and it follows that the above-described problem of deterioration of the communication distance of the RFID tag or the like occurs.
  • SUMMARY OF THE INVENTION
  • The present invention has been made in view of the above circumstances and provides an RFID tag which can be manufactured with high productivity while avoiding the deterioration of communication distance.
  • An RFID tag of the present invention is provided with a base, an antenna pattern that is provided on the base to form a communication antenna and has a tapered connection end portion which provides a connection terminal to the antenna, an electric conductor that is attached onto the connection end portion of the antenna pattern and is smaller than the connection end portion, and a circuit chip that is electrically connected to the antenna pattern via the electric conductor and performs radio communication by use of the antenna.
  • In an RFID tag of the present invention, a form in which “the antenna pattern has an inductance generation portion that generates an inductance suited to a capacitance between the connection end portion and the circuit chip and prevents performance deterioration of the antenna due to the capacitance” is a typical form.
  • In an RFID tag of the present invention, the circuit chip overhangs the connection end part of the antenna pattern, with the electric conductor pinched. As a result, it follows that the circuit chip and the connection end portion of the antenna pattern overlap each other with a gap for the electric conductor. In the part of this portion where the two overlap each other (the overlapping portion) except the conductor, there is formed a capacitor which is unnecessary in terms of design, with the circuit chip and the connection end portion which are opposed each other serving as electrodes. The capacity of this capacitor (the parasitic capacity) is proportional to the area of the overlapping portion and inversely proportional to the gap between the circuit chip and the connection end portion of the antenna pattern in this overlapping portion.
  • Incidentally, in manufacturing an RFID tag of the present invention, it is a general practice to adopt a method by which the electric conductor is attached to the circuit chip and after that, the circuit chip is heated while the circuit chip is being pressed against the base to ensure that the electric conductor is attached to the connection end portion of the antenna pattern. When this method is adopted, the electric conductor, along with part of the connection end portion, sinks into the base.
  • In a case where the circuit chip is mounted in such a manner as to be shifted toward the leading end side of the connection end portion, the area of the overlapping portion becomes narrow and a decrease proportional to this narrowing of the are occurs in the parasitic capacity. In this case, the position where the electric conductor is attached to the connection end portion is shifted toward the leading end side of the connection end portion. And because the connection end portion is tapered and its strength decreases toward the leading end, the electric conductor sinks deep into the base, with the result that the gap between the circuit chip and the connection end portion of the antenna pattern in the overlapping portion becomes narrow and that an increase inversely proportional to this narrowing of the gap occurs in the parasitic capacity. As a result, the above-described decrease and increase cancel each other out and, therefore, it follows that a change scarcely occurs in the parasitic capacity even when the mounting position of the circuit chip is shifted toward the leading end side of the connection end portion.
  • On the other hand, in a case where the circuit chip is mounted in such a manner as to be shifted toward the base side of the connection end portion, contrary to the above-described case, the area of the overlapping portion widens and the gap between the circuit chip and the connection end portion of the antenna pattern in the overlapping portion widens. As a result, an increase proportional to the widening of the area of the overlapping portion and a decrease inversely proportional to the widening of the gap between the circuit chip and the connection end portion occur in the parasitic capacity and the two cancel each other out and, therefore, it follows that a change scarcely occurs in the parasitic capacity even when the mounting position of the circuit chip is shifted toward the base side of the connection end portion.
  • As described above, in an RFID tag of the present invention, the parasitic capacity is stable for manufacturing reasons and, therefore, the parasitic capacity can be predicted in a stable manner. As a result of this, it is possible to take, as a measure related to a parasitic capacity, a measure capable of obtaining high productivity without imposing burden on manufacturing, for example, providing an antenna pattern having an inductance generation portion which causes an inductance determined on the basis of a predicted parasitic capacity to be generated. In other words, according to the present invention, it is possible to obtain an RFID tag capable of being manufactured with high productivity while avoiding the deterioration of communication distance.
  • As described above, according to the present invention, it is possible to provide an RFID tag capable of being manufactured with high productivity while avoiding the deterioration of communication distance.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • Preferred embodiments of the present invention will be described in detail based on the following figures, wherein:
  • FIGS. 1(A) and 1(B) are a front view and a side view, respectively, of the first embodiment of the present invention;
  • FIG. 2 is an enlarged view which shows the shape of a pad of the antenna pattern of FIG. 1;
  • FIGS. 3(A) and 3(B) are an enlarged front view and an enlarged side view, respectively, of the area near a pad in a case where a circuit chip is mounted in such a manner as to be shifted toward the leading end side of the triangular pad from a standard position;
  • FIGS. 4(A) and 4(B) are an enlarged front view and an enlarged side view, respectively, of the area near a pad in a case where a circuit chip is mounted in such a manner as to be shifted toward the base side of the triangular pad from a standard position;
  • FIG. 5 is an enlarged view which shows the shape of an antenna pattern in an RFID tag of the second embodiment of the present invention;
  • FIG. 6 is an enlarged view which shows the shape of an antenna pattern in an RFID tag of the third embodiment of the present invention; and
  • FIG. 7 is an enlarged view which shows the shape of an antenna pattern in an RFID tag of the fourth embodiment of the present invention.
  • DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • FIGS. 1(A) and 1(B) are a front view and a side view, respectively, of the first embodiment of the present invention. However, in the front view shown here, the internal structure is seen through from the front of an RFID tag and in the side view shown here, the internal structure is seen through from the side of an RFID tag.
  • An RFID tag 1 shown in FIGS. 1(A) and 1(B) is constituted by an antenna pattern 3 provided on a base sheet 2, a circuit chip 4 which is bonded onto the base sheet 2 with an epoxy adhesive 8 and is electrically connected to the antenna pattern via a bump 6, an inductance pattern 5 which is electrically connected to the antenna pattern 3 and generates an inductance, and a cover sheet 7 which covers these antenna pattern 3, circuit chip 4 and inductance pattern 5 and bonded to the base sheet 2. The cover sheet 7 is usually formed from a material selected from among PET materials, polyester materials, polyolefin materials, polycarbonate materials, acrylic materials, etc.
  • In this first embodiment, the above-described base sheet 2, circuit chip 4 and bump 6 correspond, respectively, to an example of the base, circuit chip and electric conductor according to the present invention. And a combination of the antenna pattern 3 and the inductance pattern 5 corresponds to an example of the antenna pattern according to the present invention, and inductance pattern 5 corresponds to an example of the inductance generation portion according to the present invention.
  • This RFID tag 1 receives the energy of an electromagnetic field released by a reader/writer as electric energy by use of the antenna pattern 3 and the circuit chip 4 is driven by the electric energy, whereby the communication action is realized.
  • This RFID tag 1 is made by performing the following procedure. First, the bump 6 is attached to the circuit chip 4. The end portion of the antenna pattern 3 on the circuit chip 4 side provides a pad 3 a to electrically connect this antenna pattern 3 to other parts. The circuit chip 4 to which the bump 6 is attached is pressed against the base sheet 2 to ensure that the bump 6 is attached to the pad 3 a and at the same time, the circuit chip 4 is fixed with an adhesive 8 and heated.
  • The end portion of the antenna pattern 3 on the circuit chip 4 side provides the pad 3 a to electrically connect this antenna pattern 3 to the circuit chip 4 via the bump 6, and this pad 3 a and the circuit chip 4 partially overlap each other in such a manner as to pinch the bump 6 between the two, with a gap for the bump 6. In the portion where the two overlap each other (the overlapping portion), the adhesive 8 is filled in the area except the bump 6, with the result that a capacitor which is unnecessary in terms of design is formed in the above-described overlapping portion, with the pad 3 a and the circuit chip 4 serving as electrodes. The capacity of this capacitor (the parasitic capacity) prevents the input of power from the antenna pattern 3 to the circuit chip 4, causing troubles such as the deterioration of the communication distance of the RFID tag 1. Therefore, the present embodiment is constituted in such a manner that by causing a resonance to occur between the inductance generated by the inductance pattern 5 provided on the antenna pattern 3 side and the above-described parasitic capacity, this parasitic capacity is canceled out.
  • In the present embodiment, the inductance is found using Eq. (1) below on the basis of a parasitic capacity (standard capacity) which is considered to be generated in the overlapping portion of the circuit chip 4 and the pad 3 a on the assumption that the circuit chip 4 is mounted in a standard position determined in performing designing. In Eq. (1), “L” is an inductance, “C” is the standard capacity, and “f” is resonance frequency.
    (2πf)2=1/(L×C)  (1)
  • On the assumption that the circuit chip 4 is mounted in the standard position, the standard capacity C is found using Eq. (2) below, where the area of the overlapping portion of the circuit chip 4 and of the pad 3 a (the standard area) is denoted by “S,” the gap between the circuit chip 4 and the pad 3 a (the standard gap) is denoted by “D,” and the dielectric constant of the adhesive 8 is denoted by “ε.”
    C=ε×S/D  (2)
  • Variations ascribed to the accuracy of manufacture etc. exist in the mounting position of the circuit chip 4, and hence it follows that the area of an actual overlapping portion of the circuit chip 4 and of the pad 3 a has some error with respect to the above-described standard area S. If the area of an actual overlapping portion differs from the standard area S, also a parasitic capacity which actually occurs in an RFID tag 1 differs from the standard capacity C. Therefore, even when the inductance pattern 5 which generates an inductance L is found on the basis of the standard capacity C, it becomes impossible to ensure the matching given by Eq. (1) between an actual parasitic capacity and the inductance L and hence there is a possibility that the parasitic capacity may not be canceled out. In the present embodiment, therefore, even when variations occur in the mounting position of the circuit chip 4, in order to ensure that an actual parasitic capacity is substantially equally to the standard capacity C, that is, the parasitic capacity is stabilized at the standard capacity C for manufacturing reasons, the shape of the pad 3 a of the antenna pattern 3 is contrived as described below.
  • FIG. 2 is an enlarged view which shows the shape of a pad of the antenna pattern of FIG. 1.
  • In FIG. 2 is shown an enlarged view of the area near the pad 3 a of the antenna pattern 3 in the RFID tag 1 in the present embodiment. As shown in FIG. 2, that the pad 3 a has the shape of a triangle the leading end of which faces the circuit chip 4. Part 3 a-1 of this pad 3 a overlaps the circuit chip 4. The above-described parasitic capacity is generated in this overlapping portion. This triangular shape of the pad 3 a corresponds to an example of the “tapered shape” according to the present invention.
  • Even in a case where variations occur in the mounting position of the circuit chip 4, the triangular pad 3 a shown in FIG. 2 is provided as a contrivance to stabilize the parasitic capacity at the standard capacity C, and the effect obtained from this pad 3 a will be described below.
  • FIGS. 3(A) and 3(B) are an enlarged front view and an enlarged side view, respectively, of the area near a pad in a case where a circuit chip is mounted in such a manner as to be shifted toward the leading end side of the triangular pad from a standard position. In this enlarged side view, the internal structure near the pad in an RFID tag 1 is seen through from the side. In the present specification, all drawings called enlarged side views are similar ones.
  • In the case where a circuit chip 4 is mounted in such a manner as to be shifted toward the leading end side of the triangular pad 3 a from a standard position P, as shown in the enlarged front view of FIG. 3(A), the area of an overlapping portion of the circuit chip 4 and of the pad 3 a is narrower than the area of an overlapping portion in a case where the circuit chip 4 is disposed in the standard position P, i.e., the above-described standard area S.
  • As described above, the circuit chip 4 is pressed against a base sheet 2, with a bump 6 pinched between the two. As a result, the bump 6 receives a depressing force from the circuit chip 4, and as shown in the enlarged side view of FIG. 3(B), the bump 6, along with part of the pad 3 a, sinks into the base sheet 2.
  • Also, the bump 6 is first attached to the circuit chip 4. For this reason, when the circuit chip 4 is mounted in such a manner as to be shifted toward the leading end side of the triangular pad 3 a from a standard position P, as in the example of FIGS. 3(A) and 3(B), the bump 6 is attached to the part near the leading end on the pad 3 a compared to the case where the circuit chip 4 is disposed in the standard position P. Because at this time the pad 3 a is in the shape of a triangle, the width W1 of the pad 3 a in a part where the bump is disposed, becomes narrower than the width W of the pad 3 a in a part where the bump is disposed when the circuit chip 4 is disposed in the standard position P. As a result of this, the strength of the part of the pad 3 a which supports the bump 6 becomes weaker than the strength obtained when the circuit chip 4 is disposed in the standard position P, and the bump 6 sinks into the base sheet 2 deeper than in the case where the circuit chip 4 is disposed in the standard position P. As a result, the gap D1 between the circuit chip 4 and the pad 3 a in the overlapping portion of the circuit chip 4 and of the pad 3 a becomes narrower than the gap between the circuit chip 4 and the pad 3 a when the circuit chip 4 is disposed in the standard position P, that is, the gap D.
  • When the circuit chip 4 is mounted in such a manner as to be shifted toward the leading end side of the triangular pad 3 a from the standard position P, as in the example of FIGS. 3(A) and 3(B), as described above, the area of the overlapping portion becomes narrower than the standard area S. As is apparent from Eq. (2) above, the parasitic capacity of the overlapping portion is proportional to the area of the overlapping portion and, therefore, the above-described narrowing of the overlapping portion reduces the parasitic capacity to a level lower than the standard capacity C. On the other hand, as is apparent from Eq. (2), the parasitic capacity is inversely proportional to the gap between the circuit chip 4 and the pad 3 a and, therefore, the shortening of the gap between the circuit chip 4 and the pad 3 a increases the parasitic capacity to a level higher than the standard capacity C. Eventually, a decrease in the parasitic capacity due to the narrowing of the area of the overlapping portion is compensated for by an increase in the parasitic capacity due to the shortening of the gap between the circuit chip 4 and the pad 3 a. That is, even when the circuit chip 4 is mounted in such a manner as to be shifted toward the leading end side of the triangular pad 3 a from the standard position P, as in the example of FIGS. 3(A) and 3(B), the parasitic capacity in the overlapping portion becomes almost equal to the standard capacity C.
  • Next, a description will be given of a case where, contrary to the example of FIGS. 3(A) and 3(B), a circuit chip 4 is mounted in such a manner as to be shifted toward the base side of a triangular pad 3 a.
  • FIGS. 4(A) and 4(B) are an enlarged front view and an enlarged side view, respectively, of the area near a pad in a case where a circuit chip is mounted in such a manner as to be shifted toward the base side of the triangular pad from a standard position.
  • In the case of FIGS. 4(A) and 4(B), as shown in the enlarged front view of FIG. 4(A), the area of the overlapping portion of the circuit chip 4 and of the pad 3 a becomes wider than the area of the overlapping portion when the circuit chip 4 is disposed in the standard position P, i.e., the above-described area standard area S. On the other hand, in this case, the width W2 of the part where the bump 6 is disposed, becomes wider than the width W of the part where the bump 6 is disposed when the circuit chip 4 is disposed in the standard position P. As a result of this, the strength of the part of the pad 3 a which supports the bump 6 becomes stronger than the strength obtained when the circuit chip 4 is disposed in the standard position P, and the bump 6 sinks into the base sheet 2 less deep than in the case where the circuit chip 4 is disposed in the standard position P. As a result, the gap D2 between the circuit chip 4 and the pad 3 a in the overlapping portion of the circuit chip 4 and of the pad 3 a becomes wider than the above-described standard gap D. The widening of the area of the overlapping portion increases the parasitic capacity to a level higher than the standard capacity C, and the widening of the gap between the circuit chip 4 and the pad 3 a reduces the parasitic capacity to a level lower than the standard capacity C. Eventually, an increase in the parasitic capacity due to the widening of the area of the overlapping portion is canceled out by a decrease in the parasitic capacity due to the widening of the gap between the circuit chip 4 and the pad 3 a. That is, even when the circuit chip 4 is mounted in such a manner as to be shifted toward the base side of the triangular pad 3 a from the standard position P, as in the example of FIGS. 4(A) and 4(B), the parasitic capacity becomes almost equal to the standard capacity C.
  • As described above by referring to FIGS. 3(A) and 3(B) and FIGS. 4(A) and 4(B), in an RFID tag 1 of the present embodiment, even when the mounting position of the circuit chip 4 is shifted from the above-described standard position P toward the lead end side or the base side of the triangular pad 3 a, the parasitic capacity becomes almost equal to the standard capacity C. That is, in an RFID tag of the present embodiment, the parasitic capacity is stable at the standard capacity C for manufacturing reasons and, therefore, the inductance L found on the basis of the standard capacity C works effectively. In this manner, in an RFID tag 1 of the present embodiment, it is possible to find an effective inductance L in the design stage and hence during manufacturing, troublesome work such as the adjustment of inductance is unnecessary and it is necessary only that an inductance pattern as designed be made. Therefore, it is possible to manufacture an RFID tag 1 of the present embodiment with high productivity while avoiding the deterioration of communication distance ascribed to the parasitic capacity.
  • Incidentally, the “tapered shape” in the present invention is not limited to the triangular shape in the above-described first embodiment and may be shapes as described below.
  • In the following, four examples in which the shape of the pad is different from that of the first embodiment will be described as the second embodiment, the third embodiment and the fourth embodiment. However, these embodiments differ from the first embodiment only in the shape of the pad, and hence in the following, descriptions will be made by paying attention to the differences from the first embodiment.
  • FIG. 5 is an enlarged view which shows the shape of an antenna pattern in an RFID tag of the second embodiment of the present invention. Incidentally, in FIG. 5, like reference numerals refer to elements similar to the component elements of the above-described first embodiment.
  • In an RFID tag 9 shown in FIG. 5, a pad 10 a of an antenna pattern 10 on which a bump 6 has a tapered shape with a rounded leading end. In the present embodiment, this shape of the pad 10 a produces the same effect as the triangular shape of the pad 3 a of the first embodiment, and variations in the parasitic capacity ascribed to variations in the mounting position of the circuit chip 4 are suppressed, with the result that this parasitic capacity becomes stable for manufacturing reasons.
  • FIG. 6 is an enlarged view which shows the shape of an antenna pattern in an RFID tag of the third embodiment of the present invention. Also in FIG. 6, like reference numerals refer to elements similar to the component elements of the above-described first embodiment.
  • In an RFID tag 11 shown in FIG. 6, a pad 12 a of an antenna pattern 12 on which a bump 6 is mounted has a tapered shape the width of which becomes narrower by stages toward the circuit chip 4 side. In the present embodiment, this shape of the pad 12 a produces the same effect as the triangular shape of the pad 3 a of the first embodiment and the tapered shape of the pad 10 a of the second embodiment with a rounded leading end and variations in the parasitic capacity ascribed to variations in the mounting position of the circuit chip 4 are suppressed, with the result that this parasitic capacity becomes stable for manufacturing reasons.
  • FIG. 7 is an enlarged view which shows the shape of an antenna pattern in an RFID tag of the fourth embodiment of the present invention. Also, in FIG. 7, like reference numerals refer to elements similar to the component elements of the above-described first embodiment.
  • In an RFID tag 13 shown in FIG. 7, a pad 14 a of an antenna pattern 14 on which a bump 6 is mounted has a semicircular shape. In the present embodiment, this shape of the pad 14 a produces the same effect as the triangular shape of the pad 3 a of the first embodiment, the tapered shape of the pad 10 a with a rounded leading end of the second embodiment, and the tapered shape, the width of which becomes narrower by stages of the pad 12 a, of the third embodiment. Again, variations in the parasitic capacity ascribed to variations in the mounting position of the circuit chip 4 are suppressed, with the result that this parasitic capacity becomes stable for manufacturing reasons.
  • As described above, according to the RFID tags of the first to fourth embodiments, the parasitic capacity is stable regardless of variations in the mounting of the circuit chip, and hence an inductance effective for canceling out the parasitic capacity is found in the design stage. As a result of this, unnecessary troublesome work such as the adjustment of inductance during manufacturing can be saved and high-productivity manufacturing becomes possible. That is, it is possible to manufacture the RFID tags of the first to fourth embodiments with high productivity while avoiding the deterioration of communication distance ascribed to the parasitic capacity.
  • In the foregoing, as examples of the antenna pattern according to the present invention, the descriptions were given of four examples of the antenna pattern 3 having the triangular pad 3 a, the antenna pattern 10 having the tapered pad 10 a with a rounded leading end, the antenna pattern 12 having the tapered pad 12 a in which the width decreases by stages toward the circuit chip side, and the antenna pattern 14 having the pad 14 a whose shape is semicircular. However, the present invention is not limited to them. As an antenna pattern of the present invention, any antenna pattern having a pad which becomes narrow toward the leading end can be used regardless of the shape of the pad.

Claims (3)

1. An RFID tag, comprising:
a base;
an antenna pattern that is provided on the base to form a communication antenna and has a semicircular connection end portion which provides a connection terminal to the antenna;
an electric conductor that is attached onto the connection end portion of the antenna pattern and is smaller than the connection end portion; and
a circuit chip that is electrically connected to the antenna pattern via the electric conductor and performs radio communication by use of the antenna.
2. The RFID tag according to claim 1, wherein the antenna pattern has an inductance generation portion that generates an inductance suited to a capacitance between the connection end portion and the circuit chip and prevents performance deterioration of the antenna due to the capacitance.
3. The RFID tag according to claim 1, wherein a parasitic capacity, which occurs in an overlapping portion where the circuit chip and the connection end portion of the antenna pattern overlap each other, is proportional to the area of the overlapping portion and inversely proportional to a gap between the circuit chip and the connection end portion of the antenna pattern.
US11/454,848 2005-03-22 2006-06-19 RFID tag Abandoned US20060244600A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP2005081398A JP2006268090A (en) 2005-03-22 2005-03-22 Rfid tag
JP2005-081398 2005-03-22
US11/142,356 US7298273B2 (en) 2005-03-22 2005-06-02 RFID tag
US11/454,848 US20060244600A1 (en) 2005-03-22 2006-06-19 RFID tag

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US11/454,848 US20060244600A1 (en) 2005-03-22 2006-06-19 RFID tag

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US11/142,356 Continuation-In-Part US7298273B2 (en) 2005-03-22 2005-06-02 RFID tag

Publications (1)

Publication Number Publication Date
US20060244600A1 true US20060244600A1 (en) 2006-11-02

Family

ID=36763249

Family Applications (3)

Application Number Title Priority Date Filing Date
US11/142,356 Expired - Fee Related US7298273B2 (en) 2005-03-22 2005-06-02 RFID tag
US11/454,848 Abandoned US20060244600A1 (en) 2005-03-22 2006-06-19 RFID tag
US11/907,289 Abandoned US20080040913A1 (en) 2005-03-22 2007-10-10 RFID tag

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US11/142,356 Expired - Fee Related US7298273B2 (en) 2005-03-22 2005-06-02 RFID tag

Family Applications After (1)

Application Number Title Priority Date Filing Date
US11/907,289 Abandoned US20080040913A1 (en) 2005-03-22 2007-10-10 RFID tag

Country Status (6)

Country Link
US (3) US7298273B2 (en)
EP (1) EP1708127A3 (en)
JP (1) JP2006268090A (en)
KR (1) KR100642617B1 (en)
CN (1) CN100412898C (en)
TW (1) TWI301244B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100108770A1 (en) * 2008-11-04 2010-05-06 Fujitsu Limited Radio frequency identification tag and antenna
US8973832B2 (en) 2012-07-23 2015-03-10 Fujitsu Limited RFID tag and RFID system

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006268090A (en) * 2005-03-22 2006-10-05 Fujitsu Ltd Rfid tag
DE102005042444B4 (en) * 2005-09-06 2007-10-11 Ksw Microtec Ag Assembly for an RFID - Transponder - antenna
CN101385202A (en) * 2005-12-14 2009-03-11 堪萨斯州立大学 Microstrip antenna for rfid device
US20080024305A1 (en) * 2006-07-28 2008-01-31 Deavours Daniel D Planar microstrip antenna integrated into container
JP4957285B2 (en) 2007-02-22 2012-06-20 富士通株式会社 Rfid tag manufacturing method of the protective member, and the protective member
US8614506B1 (en) * 2007-10-03 2013-12-24 Impinj, Inc. RFID tags with bumped substrate, and apparatuses and methods for making
JP5103127B2 (en) 2007-10-05 2012-12-19 株式会社日立製作所 Rfid tag
US8653975B2 (en) * 2008-12-03 2014-02-18 The University Of Kansas Radio-frequency identification device with foam substrate
JP5172752B2 (en) * 2009-03-23 2013-03-27 株式会社日立製作所 Rf tag reader circuit
US8564439B2 (en) 2010-05-27 2013-10-22 The University Of Kansas Microstrip antenna for RFID device
KR101687025B1 (en) * 2010-09-07 2016-12-16 삼성전자주식회사 Injection molding case having antenna pattern and manufacturing method thereof
US8947236B2 (en) * 2011-01-18 2015-02-03 Avery Dennison Corporation Sensing properties of a material loading a UHF RFID tag by analysis of the complex reflection backscatter at different frequencies and power levels
TWI453677B (en) * 2011-12-01 2014-09-21 Mutual Pak Technology Co Ltd Radio frequency identification tag and cloth having the same
WO2013082665A1 (en) * 2011-12-07 2013-06-13 Monash University Rfid and apparatus and methods therefor

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5407669A (en) * 1990-03-05 1995-04-18 Lindstrom; Richard L. Method and apparatus of a defined serumfree medical solution
US5446447A (en) * 1994-02-16 1995-08-29 Motorola, Inc. RF tagging system including RF tags with variable frequency resonant circuits
US5604485A (en) * 1993-04-21 1997-02-18 Motorola Inc. RF identification tag configurations and assemblies
US6094138A (en) * 1998-02-27 2000-07-25 Motorola, Inc. Integrated circuit assembly and method of assembly
US6239703B1 (en) * 1998-01-02 2001-05-29 Intermec Ip Corp Communication pad structure for semiconductor devices
US6265977B1 (en) * 1998-09-11 2001-07-24 Motorola, Inc. Radio frequency identification tag apparatus and related method
US20020003496A1 (en) * 2000-06-01 2002-01-10 Brady Michael John Adjustable length antenna system for RF transponders
US6407669B1 (en) * 2001-02-02 2002-06-18 3M Innovative Properties Company RFID tag device and method of manufacturing
US20040201522A1 (en) * 2003-04-10 2004-10-14 Housing Technology, Inc. RFID tag using a surface insensitive antenna structure
US6853087B2 (en) * 2000-09-19 2005-02-08 Nanopierce Technologies, Inc. Component and antennae assembly in radio frequency identification devices
US6985122B2 (en) * 2003-10-22 2006-01-10 Nathan Cohen Antenna system for radio frequency identification
US7158033B2 (en) * 2004-09-01 2007-01-02 Avery Dennison Corporation RFID device with combined reactive coupler

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5563616A (en) * 1994-03-18 1996-10-08 California Microwave Antenna design using a high index, low loss material
US6107920A (en) * 1998-06-09 2000-08-22 Motorola, Inc. Radio frequency identification tag having an article integrated antenna
US6248201B1 (en) * 1999-05-14 2001-06-19 Lucent Technologies, Inc. Apparatus and method for chip processing
US6147662A (en) * 1999-09-10 2000-11-14 Moore North America, Inc. Radio frequency identification tags and labels
US6342866B1 (en) * 2000-03-17 2002-01-29 The United States Of America As Represented By The Secretary Of The Navy Wideband antenna system
JP4480840B2 (en) * 2000-03-23 2010-06-16 パナソニック株式会社 Component mounting apparatus, and a component mounting method
WO2002099764A1 (en) * 2001-06-05 2002-12-12 Motorola, Inc. Capacitively powered data communication system with tag and circuit carrier apparatus for use therein
JP4128540B2 (en) * 2003-06-05 2008-07-30 株式会社新川 Bonding apparatus
AU2005217971B2 (en) * 2004-02-23 2010-02-18 Checkpoint Systems, Inc. Security tag and system for fabricating a tag
US7126439B2 (en) * 2004-03-10 2006-10-24 Research In Motion Limited Bow tie coupler
DE602005010708D1 (en) * 2004-07-20 2008-12-11 Nxp Bv Configuring a multi-purpose antenna for a contactless data carrier
US7353598B2 (en) * 2004-11-08 2008-04-08 Alien Technology Corporation Assembly comprising functional devices and method of making same
JP2006268090A (en) * 2005-03-22 2006-10-05 Fujitsu Ltd Rfid tag
JP2007173801A (en) * 2005-12-22 2007-07-05 Unaxis Internatl Trading Ltd Method of fitting flip chip to substrate

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5407669A (en) * 1990-03-05 1995-04-18 Lindstrom; Richard L. Method and apparatus of a defined serumfree medical solution
US5604485A (en) * 1993-04-21 1997-02-18 Motorola Inc. RF identification tag configurations and assemblies
US5446447A (en) * 1994-02-16 1995-08-29 Motorola, Inc. RF tagging system including RF tags with variable frequency resonant circuits
US6239703B1 (en) * 1998-01-02 2001-05-29 Intermec Ip Corp Communication pad structure for semiconductor devices
US6094138A (en) * 1998-02-27 2000-07-25 Motorola, Inc. Integrated circuit assembly and method of assembly
US6265977B1 (en) * 1998-09-11 2001-07-24 Motorola, Inc. Radio frequency identification tag apparatus and related method
US20020003496A1 (en) * 2000-06-01 2002-01-10 Brady Michael John Adjustable length antenna system for RF transponders
US6535175B2 (en) * 2000-06-01 2003-03-18 Intermec Ip Corp. Adjustable length antenna system for RF transponders
US6853087B2 (en) * 2000-09-19 2005-02-08 Nanopierce Technologies, Inc. Component and antennae assembly in radio frequency identification devices
US6407669B1 (en) * 2001-02-02 2002-06-18 3M Innovative Properties Company RFID tag device and method of manufacturing
US20040201522A1 (en) * 2003-04-10 2004-10-14 Housing Technology, Inc. RFID tag using a surface insensitive antenna structure
US6914562B2 (en) * 2003-04-10 2005-07-05 Avery Dennison Corporation RFID tag using a surface insensitive antenna structure
US6985122B2 (en) * 2003-10-22 2006-01-10 Nathan Cohen Antenna system for radio frequency identification
US7158033B2 (en) * 2004-09-01 2007-01-02 Avery Dennison Corporation RFID device with combined reactive coupler

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100108770A1 (en) * 2008-11-04 2010-05-06 Fujitsu Limited Radio frequency identification tag and antenna
US8276825B2 (en) 2008-11-04 2012-10-02 Fujitsu Limited Radio frequency identification tag and antenna
US8973832B2 (en) 2012-07-23 2015-03-10 Fujitsu Limited RFID tag and RFID system

Also Published As

Publication number Publication date
US20080040913A1 (en) 2008-02-21
TW200634645A (en) 2006-10-01
EP1708127A2 (en) 2006-10-04
JP2006268090A (en) 2006-10-05
CN1838157A (en) 2006-09-27
EP1708127A3 (en) 2007-05-30
KR100642617B1 (en) 2006-11-13
KR20060102460A (en) 2006-09-27
US7298273B2 (en) 2007-11-20
TWI301244B (en) 2008-09-21
US20060214793A1 (en) 2006-09-28
CN100412898C (en) 2008-08-20

Similar Documents

Publication Publication Date Title
US8668151B2 (en) Wireless IC device
JP6414606B2 (en) Electronics
AU742212B2 (en) Card mounted with circuit chip and circuit chip module
JP4854362B2 (en) Rfid tag and a method of manufacturing the same
KR100799140B1 (en) Radio frequency identificationrfid tag and manufacturing method thereof
EP2166490B1 (en) Wireless ic device and electronic apparatus
US8991712B2 (en) Coupling in and to RFID smart cards
KR100371816B1 (en) Card mounted with circuit chip and circuit chip module
US8360325B2 (en) Wireless IC device, electronic apparatus, and method for adjusting resonant frequency of wireless IC device
EP2330684A1 (en) Rfid tag, rfid tag set and rfid system
US9558440B2 (en) Wireless IC device
EP1596326A2 (en) IC card module
US20060001138A1 (en) IC-tag-bearing wiring board and method of fabricating the same
JP4075919B2 (en) Antenna unit and the non-contact ic tag
KR101899517B1 (en) Nfc card for handheld device
US8704716B2 (en) Antenna device and mobile communication terminal
EP2284949B1 (en) Wireless ic device
US7764928B2 (en) Wireless IC device and component for wireless IC device
EP1826866A1 (en) Antenna and noncontact tag
JP4885093B2 (en) Booster antenna coil
JP4393228B2 (en) Small antenna and a radio tag with it
JP4885092B2 (en) Booster antenna coil
EP1689028A1 (en) Information processing device having non-contact reader and/or writer and coil antenna for magnetic connection
US7508347B2 (en) Radio frequency integrated circuit tag and method of using the RFIC tag
US7292148B2 (en) Method of variable position strap mounting for RFID transponder

Legal Events

Date Code Title Description
AS Assignment

Owner name: FUJITSU LIMITED, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BABA, SHUNJI;REEL/FRAME:017995/0406

Effective date: 20060526