Abstract:
A tire and RFID tag combine as an assembly to include a tire and a tag package mounted to a tire tag mounting surface. The tag package includes a carrier substrate having a die receiving surface and one or more interconnection tabs mounted to the die receiving surface. The tag package further includes a dipole antenna or other antenna configuration formed by first and second antenna members having inward ends connected to respective first and second interconnection tabs on the die receiving surface and outer antenna segments extending outward from the carrier substrate. An integrated circuit die mounts to the die receiving surface and has electrical contact(s) in contacting engagement with the interconnection tab(s). A cap member or, alternatively, a cylindrical encapsulating member, may be utilized for enclosing the integrated circuit die, the carrier substrate, and the inward ends of the first and second antenna members; the outer antenna segments of the first and second antenna members extending outward from the cap member or encapsulating member in operable position against respective portions of the tire tag mounting surface.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to a highly durable RFID tag package and, more particularly, to a tire and RFID tag assembly incorporating a highly durable RFID tag package. 
     BACKGROUND OF THE INVENTION 
     Incorporation of an RFID tag into a tire can occur during tire construction and before vulcanization or in a post-cure procedure. Such tags have utility in transmitting tire-specific identification data to an external reader. UHF (ultra-high frequency) tags are typically small and utilize flexible antennas for the transmission of data. In commercially available RFID devices, the antennas are connected to solder leads of a circuit board onto which the device&#39;s integrated circuit board is mounted. When embedded into a tire, such as during within a tire sidewall during the tire construction, the device is subjected to the stress endemic to tire operation and performance. Such forces may act to cause failure of the RFID tag or failure in the mechanical and electrical connections between end of the antenna and the circuit board solder leads. Failure of the RFID tag in any form is undesirable and it is important that the RFID package be capable of ensuring the mechanical and electrical integrity of the tag antenna and the electronic circuit board throughout the tire life cycle. Accordingly, there remains a need for a UHF RFID tag package that is readily incorporated into a tire; provides the requisite durability to maintain antenna to circuit board integrity during the life of the tire and the service life of the tag. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the invention, a tire and RFID tag combine as an assembly including a tire having a tag mounting surface and a tag package mounted to the tag mounting surface. The tag package may include a carrier substrate having a die receiving surface and at least one interconnection tab mounted to the die receiving surface and composed of electrically conductive material. The tag package further includes an antenna having an end connected to the interconnection tab on the die receiving surface and an antenna segment extending outward from the carrier substrate. The tag package further includes an integrated circuit die mounted to the die receiving surface and having at least one electrical contact in contacting engagement with the interconnection tab. 
     Pursuant to another aspect of the invention, the antenna is a dipole antenna (but may be other known antenna configurations) formed by first and second antenna members having inward ends connected to respective first and second interconnection tabs on the die receiving surface and outer antenna segments extending outward from the carrier substrate. The integrated circuit die provides electrical contacts in contacting engagement with the first and second interconnection tabs. 
     In a further aspect of the invention, a cap member or, alternatively, a cylindrical encapsulating member, may be utilized for enclosing the integrated circuit die, the carrier substrate, and the inward ends of the first and second antenna members; the outer antenna segments of the first and second antenna members extending outward from the cap member or encapsulating member in operable position against respective portions of the tire tag mounting surface. 
     Definitions 
     “Aspect ratio” of the tire means the ratio of its section height (SH) to its section width (SW) multiplied by 100% for expression as a percentage. 
     “Asymmetric tread” means a tread that has a tread pattern not symmetrical about the center plane or equatorial plane EP of the tire. 
     “Axial” and “axially” means lines or directions that are parallel to the axis of rotation of the tire. 
     “Camber angle” means the angular tilt of the front wheels of a vehicle. Outwards at the top from perpendicular is positive camber; inwards at the top is negative camber. 
     “Circumferential” means lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction. 
     “Equatorial Centerplane (CP)” means the plane perpendicular to the tire&#39;s axis of rotation and passing through the center of the tread. 
     “Footprint” means the contact patch or area of contact of the tire tread with a flat surface at zero speed and under normal load and pressure. 
     “Groove” means an elongated void area in a tread that may extend circumferentially or laterally about the tread in a straight, curved, or zigzag manner. Circumferentially and laterally extending grooves sometimes have common portions. The “groove width” is equal to tread surface area occupied by a groove or groove portion, the width of which is in question, divided by the length of such groove or groove portion; thus, the groove width is its average width over its length. Grooves may be of varying depths in a tire. The depth of a groove may vary around the circumference of the tread, or the depth of one groove may be constant but vary from the depth of another groove in the tire. If such narrow or wide grooves are substantially reduced depth as compared to wide circumferential grooves which the interconnect, they are regarded as forming “tie bars” tending to maintain a rib-like character in tread region involved. 
     “Inboard side” means the side of the tire nearest the vehicle when the tire is mounted on a wheel and the wheel is mounted on the vehicle. 
     “Lateral” means an axial direction. 
     “Lateral edges” means a line tangent to the axially outermost tread contact patch or footprint as measured under normal load and tire inflation, the lines being parallel to the equatorial centerplane. 
     “Net contact area” means the total area of ground contacting tread elements between the lateral edges around the entire circumference of the tread divided by the gross area of the entire tread between the lateral edges. 
     “Non-directional tread” means a tread that has no preferred direction of forward travel and is not required to be positioned on a vehicle in a specific wheel position or positions to ensure that the tread pattern is aligned with the preferred direction of travel. Conversely, a directional tread pattern has a preferred direction of travel requiring specific wheel positioning. 
     “Outboard side” means the side of the tire farthest away from the vehicle when the tire is mounted on a wheel and the wheel is mounted on the vehicle. 
     “Radial” and “radially” means directions radially toward or away from the axis of rotation of the tire. 
     “Rib” means a circumferentially extending strip of rubber on the tread which is defined by at least one circumferential groove and either a second such groove or a lateral edge, the strip being laterally undivided by full-depth grooves. 
     “Sipe” means small slots molded into the tread elements of the tire that subdivide the tread surface and improve traction, sipes are generally narrow in width and close in the tires footprint as opposed to grooves that remain open in the tire&#39;s footprint. 
     “Slip angle” means the angle of deviation between the plane of rotation and the direction of travel of a tire. 
     “Tread element” or “traction element” means a rib or a block element defined by having a shape adjacent grooves. 
     “Tread Arc Width” means the arc length of the tread as measured between the lateral edges of the tread. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described by way of example and with reference to the accompanying drawings in which: 
         FIG. 1  is a break-away view of a tire with a RFID tag mounted or embedded onto the tire inner sidewall. 
         FIG. 2A  is an exploded assembly view of a RFID tag. 
         FIG. 2B  is an assembled view of the RFID tag package of  FIG. 2A  shown prior to application of an outer coating. 
         FIG. 2C  is an assembled view of the finished RFID cylindrical tag package. 
         FIGS. 3A ,  3 B,  3 C, and  3 D are sequential perspective views of a first assembly sequence of the RFID tag package. 
         FIG. 3E  is an tubular packaged tag. 
         FIGS. 4A ,  4 B,  4 C, and  4 D are sequential perspective views of a second assembly sequence of the RFID tag package. 
         FIGS. 5A ,  5 B,  5 C, and  5 D show an alternative through bore connection between a tag and antenna elements. 
         FIGS. 6A ,  6 B,  6 C, and  6 D show alternative connection schemes between a tag and antenna elements. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring first to  FIGS. 1 ,  2 A-C, an electronic tire tag  16  is of a conventional commercially configured type and includes an antenna formed by a pair of coiled antenna segments  40 ,  42 . An integrated circuit package (IC)  6  is mounted to a carrier substrate  22  and includes interconnection leads  38  extending from opposite IC package sides respectively. The antenna  40 ,  42  is electrically connected to the IC leads  38  and is suitably tuned to a predetermined radio frequency “f” for receiving RF signals, referred to herein as interrogation signals, from an external transceiver (not shown). 
     Operatively, the interrogation signal is received by the antenna  40 ,  42  from a remote transponder (not shown) and transmitted to the integrated circuitry within the package  36 . The integrated circuit within the package  36  processes the RF interrogation signal into a power signal for powering a logic circuit that includes conventional ROM, RAM, or other known types of memory storage devices and circuitry. Data transmission from the storage devices is thereby enabled and stored data is transmitted by the antenna  40 ,  42  back to an external reader or transponder (not shown). The tag  16  may be incorporated within various products and utilized to communicate stored data relating to such products to the remote reading device. 
     The electronic tire tag  16  is preferably wrapped with a suitable green rubber material (not shown) to form a green rubber patch (not shown) that is vulcanized and fixedly secured to a tire (not shown). Alternatively, the tag  16  may be incorporated within the green tire prior to tire cure. 
     Referring initially to  FIGS. 1 ,  2 A-C collectively, a tag and tire assembly  10  is shown. A conventionally configured tire  12  includes an inner lining  14  to which a RFID tag assembly  16  is incorporated. In the embodiment shown, without any intent to limit the invention, the RFID tag assembly  16  is attached to the inner lining  14  (but may also be embedded in any layer of the sidewall) by a suitable commercial grade adhesive  20 . Other locations or tire components may be utilized if desired without departing from the invention. The tire  12  with the tag assembly  16  incorporated therein is mounted conventionally to a rim  18 . 
     The RFID assembly  16  includes a carrier substrate  22  having a top support surface  24  on which a pair of spaced apart conductive contact pads  26 ,  28  are mounted. In general, the support surface  24  includes spaced apart contact pad receiving locations  30 ,  34  separated by a medial RFID device receiving location  32  between locations  30 ,  34 . An RFID electronic package  36  encased within a cover  37  is mounted to the support surface  24  at the medial location  32  as shown in  FIG. 2A . Attachment may be by any suitable means such as adhesive. The package  36  includes an array of contact legs  38  along opposite sides. In its intended location at location  32 , the contact legs  38  will establish electrical and mechanical contact with the contact pads  26 ,  28  on support surface  24 . 
     The RFID tag assembly  16  further includes a dipole antenna (but can be other antenna types) comprised of coiled antenna segments  40 ,  42 . The antenna segments  40 ,  42  have a respective inward end  44 ,  46  that is coupled to the contact pads  44 ,  46  by suitable means such as solder. While the ends  44 ,  46  are shown as straightened portions of the coiled segments  40 ,  42 , the ends may be in a coiled configuration if so desired. The tag assembly  16  of  FIG. 2B  may be incorporated into a tire as shown in  FIG. 1  by adhesive application  20  or other suitable means. So located, the antenna segments  40 ,  42 , and the substrate  22  will be supported by mounting surface portions of the tire inner liner  14 . Stresses introduced into the tire and acting upon the assembly  16  will be accommodated by flexure of the segments  40 ,  42  that extend from the substrate  22 . The tag assembly  16  is thus durable and capable of withstanding the highly stressed environment of a tire cavity. 
     In order to make the assembly  16  even more durable, an encapsulating casing  48  may be secured to encase the substrate, the RFID package  36  and the inward ends  44 ,  46  of the antenna segments  40 ,  42  as shown in  FIG. 2C . The casing  48  may be formed of plastics or other suitable material. The casing  48  is preferably of tubular form as shown. The tubular form of the casing  48  will protect the electronic components and connections therein from potentially damaging contact with foreign objects and the stresses acting on the assembly  16  from the tire and tire operation, as well as in shipping and handling of the assembly  16  prior to and during incorporation into a tire. 
     In  FIGS. 3A-3D  an opened or already opened IC package is shown. The connections made to the leads of the package were made to the antenna instead. The RFID die  54  is removed from an IC package and replaced. The die connections are made directly to the antenna segment ends  44 ,  46 . The die  44  is mounted directly to the substrate support surface  24 . The die  54  includes an integrated circuit  56  and peripheral contacts  58 . A contact pad  60  of conductive material is applied to the substrate surface  24 . Placement of the die  44  on the contact pad  60  establishes electrical contact between the die contacts  58  and the substrate pad  60 . The die  44  is held in place on substrate surface  24  by suitable means such as adhesive. 
     The coiled ends  62 ,  64  of the antenna segments  40 ,  42  are attached to the substrate pad  60  by suitable means such as adhesive or solder, whereby electrically connecting the antenna through pad  60  to the IC on the die  44 . The cover  37  may be affixed as shown in  FIG. 3C  by adhesive or other means to complete the assembly as shown in  FIG. 3D . The coiled antenna segments  40  are directly coupled at the coiled inner ends  62 ,  64  to the pad  60  and extend free of the sealed compartment formed by the cover  37  and the substrate  22 . Placement of the completed assembly into a tire is achieved by affixing the substrate to a tire mounting surface such as the inner liner by suitable means such as adhesive. The antenna segments  40 ,  42  rest against the tire mounting surface but preferably extend adhesive free from containment of cover  37  and substrate  22 . Accordingly, as with the embodiment of  FIGS. 2A-D , the RFID tag assembly  16  is sealed, durable, and capable of withstanding the use-induced stresses of the tire.  FIG. 3E  shows a tubular casing surrounding the RFID package of  FIG. 3C  as an alternative packaging configuration. The tubular casing  66  provides a protective enclosure of the RFID electronics package during shipment, handling, installation, and tire use. 
       FIGS. 4A-D  show another alternative embodiment of an RFID Assembly  68 . The cover  70  is removed (or an already opened package is used) in  FIG. 4B  to illustrate placement of the die  54  on the support surface  24  of the substrate  22 . The conductive pad  60  is secured to the surface  24  as with the embodiment of  FIGS. 3A-D  discussed previously. A series of depending support legs  72  are secured to opposite sides of the substrate  22  and each leg  72  includes a bend  71  transitioning into a support foot  73  that is generally coplanar with the underside of the substrate  22 . A medial portion of each side of the substrate is support leg-free to allow access to the contact pad  60  by the coiled ends  62 ,  64  of antenna segments  40 ,  42  as will be appreciated in  FIGS. 4C and 4D . The cover  70  is attached over the substrate  22  and sealed by suitable means such as adhesive compound. The completed assembly  16  of  FIG. 4D  is attached to a tire surface such as the inner liner by adhesive applied to the underside of the substrate  22  as well as the undersides of the feet  73  of the support legs. The resultant tag  16  is durable and the legs  72  aid in attachment of the unit  16  to the tire by increased anchoring provided by adhesive connection of the feet  73  to the tire surface. 
       FIGS. 5A-C  show an alternative configuration for the RFID tag assembly  16 . Contact pads  74 ,  76 ,  78 ,  80  are secured to top and bottom surfaces of the substrate  22 . An IC die  56  is mounted to a top surface of the substrate and includes contacts  58  along opposite die sides. Alternately, the contacts could also be inductively coupled using a ferrous material. Plated through holes  82  extend through the substrate  22  and are positioned to electrically connect the contact pads  74 ,  78  on one substrate side with the pads  76 ,  80  on the opposite substrate side (not shown). The coiled ends  64 ,  66  of the antenna segments  40 ,  42  are secured to the pads  76 ,  80  and electrically connect with the die contacts  58  through the plated through holes  82 ,  84 . Free segments  50 ,  52  of the antenna segments  40 ,  42 , respectively, project free from the substrate  22  as with the embodiments shown and discussed previously. It will be appreciated that the assembly of  FIG. 5C  may be incorporated into a tire by adhesive attachment of the substrate  22  to a tire surface as described previously. Preferably, however, the electronic die and substrate with the ends  64 ,  66  of the antenna segments  40 ,  42  will be encased within a tubular casing  86  as shown in  FIG. 5D  to better protect the electronic tag during shipping, attachment to a tire, and tire use. 
       FIGS. 6A-6D  show other alternative embodiments for the RFID tag assembly  16 . In  FIG. 6A , the RFID package  36  provides edge contacts that are directly coupled to the ends  62 ,  64  of the antenna segments  40 ,  42  by suitable means such as solder. The electronics package  36  may then be encased into a tubular package as shown in  FIG. 6B .  FIG. 6C  shows a die configured having dependent contact legs  38  that are attached directly to the coiled antenna segment ends  62 ,  64 .  FIG. 6D  shows encasement of the package of  FIG. 5C  within a tubular casing  88  for added protection and durability as described previously. 
     From the foregoing, it will be understood that the subject invention satisfies a need for a UHF RFID tag package that is readily incorporated into a tire; provides the requisite durability to maintain antenna to circuit board integrity during the life of the tire and the service life of the tag. The tag assemblies described readily integrate 0.8 and 1.4 pitch coil antennas directly into a plastic IC package either by opening the IC package and keeping the die intact ( FIGS. 2A-2D ) or by opening the IC package and removing the die ( FIGS. 3A-D ). In the first approach, the connections made to the leads are made directly to the antenna instead. The possibility of failure of a lead to IC connection is thereby eliminated. A portion (inward coiled end) of the antenna is embedded in the IC when it is re-sealed to further secure the integrity of the antenna to IC attachment. 
     In the latter approach of  FIGS. 3A-3D , the die is replaced on the carrier substrate and the die connections are made to the antennas. Likewise, inward coiled ends of the antenna segments are embedded in the IC when it is re-sealed. 
     Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.