Abstract:
An electronic packaging system includes an electronic device. The electronic packaging system also includes a flexible material located adjacent a plurality of sides of the electronic device. The electronic device is located in a cavity in the flexible material. The flexible material has a first height and a first width. The electronic device has a second height. The first height is greater than the second height and the first width is greater than the first height so the flexible material protects the electronic device from loading.

Description:
RELATED APPLICATIONS 
   This patent application claims the benefit of Provisional Patent Applications 60/818,567, filed Jul. 5, 2006 and 60/819,159, filed Jul. 7, 2006, both entitled “RFID Tag Packaging System,” and both incorporated herein by reference. 
   This provisional patent application is related to commonly assigned U.S. Pat. No. 6,529,127, “System for Remote Powering,” issued Mar. 4, 2003, incorporated herein by reference. 
   This application is also related to the following commonly assigned U.S. Patent Applications, all of which are incorporated herein by reference: 
   Data collection and Storage Device, U.S. patent application Ser. No. 09/731,066, filed Dec. 6, 2000. 
   Energy Harvesting for Wireless Sensor Operation and Data Transmission, U.S. patent application Ser. No. 10/379,223, filed Mar. 5, 2003. 
   Shaft Mounted Energy Harvesting for Wireless Sensor Operation and Data Transmission, U.S. patent application Ser. No. 10/769,642, filed Jan. 31, 2004. 
   Robotic system for powering and interrogating sensors, U.S. patent application Ser. No. 10/379,224, filed Mar. 5, 2003. 
   Structural damage detection and analysis system, U.S. Provisional Patent Application No. 60/729,166, filed Oct. 21, 2005. 
   Wireless Vibrating Strain Gauge for Smart Civil Structures, U.S. patent application Ser. No. 11/431,194, filed May 10, 2006. 
   High Speed Energy Harvesting Data Acquisition System, U.S. Provisional Patent Application No. 60/715,987, Sep. 9, 2005. 
   Sensor Powered Event Logger, U.S. Provisional Patent Application No. 60/753,481, Dec. 21, 2005. 
   Method for Integrating an energy harvesting circuit into a PZ element&#39;s electrodes, U.S. Provisional Patent Application No. 60/753,679, Dec. 21, 2005. 
   Method for Integrating an energy harvesting circuit into a PZ element&#39;s electrodes, U.S. Provisional Patent Application No. 60/762,632, Jan. 26, 2006. 

   BACKGROUND 
   RFID tags and other electronic devices, such as those for stimulating or sensing, may be located on substrates, such as pipes, girders, I-beams, vehicles, bridges, buildings, machinery, and other structures, to provide identification or to check for cracks, delamination, corrosion, or other degradation or damage. 
   No satisfactory scheme has been implemented to provide adequate protection for the electronic devices when mounted on structures subject to mechanical stress, such as from the load experienced when pipes bang together on the electronic device. Hard surfaced packages can be crushed or sheared off the pipe. Adding to expense, different hard surfaced packages may be needed for mounting to pipes or other surfaces that have different curvatures. Without adequate protection, RFID tags and other electronic devices can be damaged and rendered inoperable while attached to the structure. Thus a better scheme is needed to reduce or eliminate the loading on electronic devices, while providing sufficient flexibility for mounting to surfaces of different shape, and this scheme is provided by this patent application. 
   SUMMARY 
   One aspect of the present patent application is an electronic packaging system that includes an electronic device and an array of surface elements surrounding the electronic device. A plurality of the surface elements of the array have a first height. The electronic device has a second height. The first height is greater than the second height so the array of surface elements protects the electronic device from loading. 
   Another aspect of the present patent application is a protective system, comprising a hard cap and a gel. The gel is within the hard cap. The hard cap has an opening for allowing the gel to leave when pressure is applied to the hard cap. 
   Another aspect of the present patent application is an electronic packaging system that includes an electronic device, a first flexible backing, a second flexible backing, and an array of surface elements. A first portion of the array surrounds the electronic device and is mounted to the first backing. A second portion of the array surrounds the electronic device and is mounted to the second backing. The first portion of the array is interlocked with the second portion of the array. 
   Another aspect of the present patent application is an electronic packaging system, comprising an electronic device and a first flexible member. The first flexible member includes a first portion of an array of surface elements and a first flexible backing. The first portion of the array of surface elements is integral with the first flexible backing and surrounds the electronic device. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing will be apparent from the following detailed description, as illustrated in the accompanying drawings, in which: 
       FIG. 1   a  is a three dimensional view of a first layer of a flexible protective package for an electronic device; 
       FIG. 1   b  is a top view of the flexible protective package of  FIG. 1 ; 
       FIG. 1   c  is a three dimensional view of two layers of a flexible protective package for an electronic device; 
       FIG. 1   d  is a side view of a drawing of a photograph of two layers of the interlocking flexible material used for the protective package of  FIG. 1   c;    
       FIG. 2   a  is a three dimensional view of an electronic device mounted on a sheet of insulating carrier that has antennas  56  previously patterned thereon and that is mounted on a pad to provide additional spacing for the antennas from a metal substrate; 
       FIG. 2   b  is a top view of the flexible protective package with a hole cut in the interlocking flexible material; 
       FIG. 2   c  is a cross sectional view of the flexible protective package with a protected electronic device mounted on a sheet of insulating carrier extending through the hole cut in the interlocking flexible material of  FIG. 2   b;    
       FIG. 2   d  is a cross sectional view of the flexible protective package of  FIG. 2   c  with the second layer of interlocking flexible material attached; 
       FIG. 2   e  is a cross sectional view of the double layer flexible protective package of  FIG. 2   d  being pressed for adhesion to a pipe; 
       FIG. 2   f  is a cross sectional view of the double layer flexible protective package of  FIG. 2   e  after adhesive attachment to the pipe and after a sealant layer has been applied; 
       FIG. 2   g  is a cross sectional view of the double layer flexible protective package of  FIG. 2   e  but with the electronic device located on the layer away from the pipe; 
       FIG. 2   h  is a cross sectional view of the double layer flexible protective package of  FIG. 2   g  after adhesive attachment to the pipe and after a sealant layer has been applied; 
       FIGS. 2   d ′,  2   e ′,  2   f ′,  2   g ′, and  2   h ′ correspond to  FIGS. 2   d ,  2   e ,  2   f ,  2   g , and  2   h  except that the first and second dual lock materials are shown pushed fully together so mushroom stems contact front surfaces of corresponding insulating carriers; 
       FIG. 3  is a three dimensional view of several connected electronic devices mounted in separate cavities in the flexible protective package of the present patent application and mounted on a pipe; 
       FIG. 4  is a cross sectional view of a single dual lock material  22   a  used to provide protection for electronic device  20  with adhesive provided on each mushroom stem to adhesively connect each mushroom stem  26   a  to a substrate; 
       FIG. 5   a  is a three dimensional view of a one layer structure with ribs for providing flexible packaging for an electronic device that may be mounted on a substrate having a one dimensional curvature; 
       FIG. 5   b  is a cross sectional view of the one layer structure of  FIG. 5   a;    
       FIG. 6   a  is a cross sectional view of a two layer structure with alternating interlocking ribs for providing flexible packaging for an electronic device that may be mounted on a substrate having a one dimensional curvature; 
       FIG. 6   b  is a cross sectional view of a two layer structure with alternating interlocking ribs for providing flexible packaging for an electronic device on an insulating carrier connected to the bottom layer that is connected to an antenna located on the top layer; 
       FIG. 7  is a cross sectional view of a two layer structure with interlocking extensions and receptacles that include latches; 
       FIG. 8   a  is a cross sectional view of the double layer flexible protective package of  FIG. 2   e  but with the electronic device protected by a hard cap; 
       FIG. 8   b  is a cross sectional view of one embodiment of the hard cap of  FIG. 8   a , with openings along its surface so gel provided under the hard cap has room to leave when pressure is applied to the hard cap; and 
       FIG. 8   a ′ is a cross sectional view of the double layer flexible protective package of  FIG. 8   a  but the first and second dual lock materials are shown pushed fully together so mushroom stems contact front surfaces of corresponding insulating carriers. 
   

   DETAILED DESCRIPTION 
   The present patent application provides a flexible packaging system that vastly reduces or eliminates loading that can otherwise cause damage to electronic devices mounted to pipes, girders, I-beams, vehicles, bridges, buildings, machinery, and other structures. The electronic devices can include RFID tags, sensors, and/or actuators. It can include a microprocessor and memory for storing programs or data. It can be passive or active. The active device can be a wireless communications device, such as an RF transmitter, receiver, or transceiver. Alternatively the active device can include an optical transmitter or an acoustic transmitter. Various other electronic components can also be included, such as an A/D converter, an amplifier, a filter, a power supply, and a voltage regulator, as shown in the above mentioned commonly assigned patent applications incorporated herein by reference. 
   A large number of electronic devices can be provided on one or more substrates. For example one electronic device can be located on each pipe section of a large number of pipe sections stored for use in oil drilling or in an oil pipeline. The present patent application provides a flexible packaging technique for an RFID tag or other electronic device to be mounted on each pipe section and for those devices to survive intact while the pipe sections are roughly handled and harshly banged against each other or banged against other equipment. The technique provides a flexible package so the same package can be used regardless of the diameter of the pipe. 
   In this application “on” a substrate means on a surface of the substrate. “On” a substrate also means embedded within the substrate. Thus, a module mounted on a surface of a pipeline is mounted on the pipeline. A module located embedded within concrete is still considered to be mounted on the concrete. 
   In one embodiment electronic device  20  was mounted on first 3M Dual Lock Reclosable Fastener SJ3541 (“dual lock material”)  22   a , available from 3M company, St. Paul, Minn., as shown in  FIGS. 1   a ,  1   b ,  1   c . Electronic device  20  can be an RFID chip, a sensor, an actuator, or any other electronic device. In one experiment antennas  24  were soldered to RFID chip  20  which was then placed on planar backing  25   a  of first dual lock material  22   a  with antennas  24  extending between mushroom stems  26  of first dual lock material  22   a , as shown in  FIGS. 1   a ,  1   b . Chip  20  can be protected with UV cureable encapsulant  27 . 
   A line drawing of a photograph of dual lock material  22   a ,  22   b  in  FIG. 1   d  shows interlocking mushroom stems  26   a ,  26   b  of first and second dual lock materials  22   a ,  22   b  pressed against opposite planar backings  25   a ,  25   b . So pushed together, interlocking mushroom stems  26   a ,  26   b  resist further compression. 
   Mushroom stems  26   a  of first dual lock material  22   a  had previously been cut off in region  28   a  of first dual lock material  22   a , as shown in  FIG. 1   b  so top surface  30  of RFID chip  20  was substantially below top surface  32   a  of mushroom stems  26   a . The cutting was accomplished with a razor blade but mushroom stems  26   a  can also be removed in selected regions with a machine tool, such as an end mill. 
   Antennas  24  were fabricated of copper wire but they could be fabricated of a flexible conductor that does not easily corrode, such as tin, tinned copper, aluminum, gold, beryllium copper, NiTi, silver, conductive epoxy, conductive elastomer, and conductive ink. NiTi is a superelastic material. Antennas  24  can also be fabricated of a conductive tape or be formed using standard flex printed circuit fabrication techniques of a conductive copper on an insulating flex material, such as polyimide. 
   In this embodiment, second dual lock material  22   b  can also have its mushroom stems cut off in region  28   b  of electronic device  20 , as shown in  FIG. 1   c , and second dual lock material  22   b  can be pressed on to first dual lock material  22   a  to form cavity  38  around electronic device  20  and to form protective package  40  for electronic device  20 . In protective package  40  the array of interlocking mushroom stems  26   a ,  26   b  surrounding electronic device  20  substantially prevents transfer of impact force to electronic device  20 . 
   Any small electronic device could be used in the place of electronic device  20 . In an experiment, a very sensitive pressure sensor was used in place of electronic device  20 . The pressure sensor was wirelessly connected to an oscilloscope to display the force. The pressure sensor was first shown to be sensitive to tiny forces exerted by slight finger pressure, on the order of grams of force. With the pressure sensor in place in interlocking first and second dual lock materials  22   a ,  22   b  which was adhesively connected to a first pipe, protective package  40  was subjected to repeated blows from a second pipe. The oscilloscope showed that the pressure sensor experienced no measurable pressure from any of the blows of one pipe slamming into the other. Only when a sharp edge of one pipe was jammed onto the region of the pressure sensor was a pressure detected. When protective package  40  was later disassembled the pressure sensor continued to be sensitive to slight pressure from a finger, demonstrating that it continued to function normally and that protective package  40  successfully protected it from the blows. 
   In another embodiment, electronic device  20  is mounted on a sheet of insulating carrier  54   a , such as polyimide that may have antennas  56  previously patterned thereon, as shown in  FIG. 2   a . Insulating carrier  54   a  can be mounted on pad  58  to provide additional spacing for antenna  56  from a metal substrate, such as a pipe, to which pad  58  is mounted. Pad  58  can simply be an adhesive or it can include another layer of polyimide with layers of adhesive on either side. 
   Hole  60   a  is cut in dual lock material  22   a , removing both mushroom stems  26   a  and planar backing  25   a  of first dual lock material  22   a  in hole  60   a , as shown in  FIG. 2   b . Hole  60   a  is sized to allow electronic device  20  mounted on sheet of insulating carrier  54   a  to be inserted there through while sheet of insulating carrier  54   a  is adhesively attached to back surface  62   a  of planar backing  25   a  of first dual lock material  22   a , as shown in  FIG. 2   c . Adhesive available on back surface  62   a  of planar backing  25   a  first dual lock material  22   a  can be used for this purpose. 
   Protective wax or butyl rubber  64  can be provided on electronic device  20  to protect electronic device  20  from moisture that the structure to which the package is mounted may experience, as also shown in  FIG. 2   c . A second layer of polyurethane material  66  or another such material can be used for additional shock protection. 
   Second dual lock material  22   b , with mushroom stems  26   b  cut off or with its own hole  60   b  is then pressed on to first dual lock material  22   a  to form cavity  68  around electronic device  20  and to form protective package  70  for electronic device  20 , as shown in  FIG. 2   d . In protective package  70  the array of interlocking mushroom stems  26   a ,  26   b  surrounding electronic device  20  substantially prevents transfer of impact force to electronic device  20 . 
   Protective package  70  is mounted to pipe  72 , as shown in  FIG. 2   e . Layer of adhesive  74   a  provided on back surface  76   a  of insulating carrier  54   a  is pressed against pipe  72  with driver  78 . Adhesive  74   a  can be a pressure sensitive adhesive. An epoxy can also be used. Driver  78  includes hard layer  80  and soft rubber pad  82  to provide the force on flexible protective package  70  to adhere it to curved pipe  72 . Spray on sealant layer  84 , such as urethane, can then be applied, as shown in  FIG. 2   f.    
   Protective package  70  can be mounted to pipe  72  upside down, as shown in  FIG. 2   g . Layer of adhesive  74   b  is provided on back surface  62   b  of planar backing  25   b  of second dual lock material  22   b . Alternatively, if insulating layer  54   b  is provided on back surface  62   b  of planar backing  25   b , layer of adhesive  74   b  is provided on back surface  76   b  of insulating layer  54   b . Spray on sealant layer  84  can be applied, as shown in  FIG. 2   h.    
     FIGS. 2   d ′,  2   e ′,  2   f ′,  2   g ′, and  2   h ′ correspond to  FIGS. 2   d ,  2   e ,  2   f ,  2   g , and  2   h  except that first and second dual lock materials  22   a ,  22   b  are shown pushed fully together so mushroom stems  26   a ,  26   b  contact front surfaces  86   a ,  86   b  of corresponding planar backing  25   a ,  25   b  of first and second dual lock materials  22   a ,  22   b . In this position mushroom stems  26   a ,  26   b  strongly resist further compression of dual lock materials  22   a ,  22   b , providing excellent protection to electronic device  20  in cavity  68 . 
   Several electronic components can be mounted using this technique. For example, active RF transceiver  96 , fractal antenna  98 , and battery  100  are each mounted in their own cavity  102   a ,  102   b ,  102   c  within first and second dual lock materials  22   a ,  22   b  mounted on pipe  72 , as shown in  FIG. 3 . Although a single cavity can be used, the presence of interlocking mushroom stems  26   a ,  26   b  (see  FIGS. 2   f ,  2   h ,  2   f ′, and  2   h ′) between each component  96 ,  98 ,  100  provides additional strength and resistance to compressive force as compared to providing all components in a single cavity. 
   A single dual lock material  22   a  can also be used to provide excellent protection for electronic device  20 . In this embodiment, adhesive  106  is provided on each mushroom stem  26   a  to adhesively connect each mushroom stem  26   a  to pipe  72 , as shown in  FIG. 4 . While advantage from interlocking stems is not obtained, mushroom stems  26   a  still provide substantial resistance to compressive forces, and protective package  108  is somewhat thinner than protective package  40 ,  40 ′ of  FIG. 1   c ,  1   d ,  FIG. 2   d - 2   h , and  FIG. 2   d ′- 2   h ′ with their interlocking mushroom stems. 
   Dual lock material  22   a ,  22   b  has advantage in that it is flexible in all directions, so it can be attached to a surface curving in more than one direction, such as a sphere, a vehicle surface, or a body part, such as a foot, a knee, or a hip. 
   Different structures can be used instead of mushroom stems. For example, a one layer structure with ribs  120  can be used for providing flexible packaging for a substrate with a one dimensional curvature, such as a pipe, as shown in  FIG. 5   a ,  5   b.    
   Alternatively a two layer structure with alternating interlocking ribs  122   a ,  122   b  can be used, as shown in  FIG. 6   a . In this embodiment, alternating interlocking ribs  122   a ,  122   b  allow layers  124   a  and  124   b  to be identical to each other. For interconnecting, layer  124   b  may just be displaced one row of ribs to provide mating alignment. Alternatively, two different layers can be provided, one with extensions like  126   a  on all its ribs, the other with receptacles like  126   b  on all its ribs. 
   While electronic device  20  is provided on insulating carrier  54  connected to bottom layer  124   b  that will be bonded to pipe  72 , antennas  130   a ,  130   b  can be formed on second insulating carrier  132  that is connected to top layer  124   a , as shown in  FIG. 6   b . Pads  134   a ,  134   b  of conductive elastomer are provided on pads  136   a    136   b  on insulating carrier  54  to electrically connect antennas  130   a ,  130   b  to electronic device  20 . 
   Other designs for surface elements can be used that still provide a flexible material. For example round extensions  126   a  and round receptacles  126   b , with cross sections similar to those shown for interlocking ribs  122 , can replace mushroom heads on layers of flexible material, as also shown in  FIG. 6   a ,  6   b , except in this case  FIG. 6   a ,  6   b  are understood as cross sections through a two dimensional array of stems instead of through rows of ribs. This would better constrain the mushroom heads and provide improved resistance to impact loads and better control of the height of the layered assembly. 
   Such extensions and receptacles can be designed with latches  138   a ,  138   b , as shown in  FIG. 7 , and/or adhesive can be provided between dual layers so that once snapped together the two layers could not be taken apart without destroying it. Tags would then be permanently packaged and mounted and one could detect whether the tag had been tampered with, discouraging theft and counterfeiting attempts. 
   In another embodiment, a dome shaped hard cap  140  can be provided over electronic device  20  to provide additional protection from blows, as shown in  FIG. 8   a . Hard cap  140  can be fabricated of a material, such as epoxy or plastic. Hard cap  140 ′ can have openings  142  along its surface so gel  144  provided under hard cap  140 ′ has room to leave when pressure is applied to hard cap  140 ′ so a reduced force is transmitted to electronic device  20 , as shown in  FIG. 8   b . Gel  144  can be fabricated of a material such as room temperature vulcanized rubber, also known as RTV. It can also be “Hi-TAC” polyurethane material from Av-DEC Aviation Devices and Electronic Components, L.L.C., Fort Worth, Tex. A colored gel can be used to make an impact highly detectable. 
   In  FIG. 8   a ′ first and second dual lock materials  22   a ,  22   b  are shown pushed together so mushroom stems  26   a ,  26   b  contact front surfaces  86   a ,  86   b  of corresponding planar backing  25   a ,  25   b  of first and second dual lock materials  22   a ,  22   b . In this position mushroom stems  26   a ,  26   b  strongly resist further compression of first and second dual lock materials  22   a ,  22   b , providing excellent protection to electronic device  20  in cavity  68 . 
   In normal use, first and second dual lock materials  22   a ,  22   b  may shift apart and together within the constraints of the latches provided by the mushroom caps and the front surfaces of the insulating carriers. 
   A material, such as polyimide, polyurethane, or silicone rubber provided in the spaces between mushroom stems  26   a ,  26   b  can hold dual lock materials  22   a ,  22   b  in one such position, such as the one shown in  FIG. 1   d.    
   Damaging blows to the package could be detected by inclusion of a sensor, such as a pressure sensor, along with electronic components for receiving and transmitting the data, as described in the commonly assigned U.S. patent applications listed herein above incorporated herein by reference. 
   While the disclosed methods and systems have been shown and described in connection with illustrated embodiments, various changes may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.