RFID tag packaging system

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.

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.

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 device20was mounted on first 3M Dual Lock Reclosable Fastener SJ3541 (“dual lock material”)22a, available from 3M company, St. Paul, Minn., as shown inFIGS. 1a,1b,1c. Electronic device20can be an RFID chip, a sensor, an actuator, or any other electronic device. In one experiment antennas24were soldered to RFID chip20which was then placed on planar backing25aof first dual lock material22awith antennas24extending between mushroom stems26of first dual lock material22a, as shown inFIGS. 1a,1b. Chip20can be protected with UV cureable encapsulant27.

A line drawing of a photograph of dual lock material22a,22binFIG. 1dshows interlocking mushroom stems26a,26bof first and second dual lock materials22a,22bpressed against opposite planar backings25a,25b. So pushed together, interlocking mushroom stems26a,26bresist further compression.

Mushroom stems26aof first dual lock material22ahad previously been cut off in region28aof first dual lock material22a, as shown inFIG. 1bso top surface30of RFID chip20was substantially below top surface32aof mushroom stems26a. The cutting was accomplished with a razor blade but mushroom stems26acan also be removed in selected regions with a machine tool, such as an end mill.

Antennas24were 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. Antennas24can 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 material22bcan also have its mushroom stems cut off in region28bof electronic device20, as shown inFIG. 1c, and second dual lock material22bcan be pressed on to first dual lock material22ato form cavity38around electronic device20and to form protective package40for electronic device20. In protective package40the array of interlocking mushroom stems26a,26bsurrounding electronic device20substantially prevents transfer of impact force to electronic device20.

Any small electronic device could be used in the place of electronic device20. In an experiment, a very sensitive pressure sensor was used in place of electronic device20. 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 materials22a,22bwhich was adhesively connected to a first pipe, protective package40was 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 package40was 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 package40successfully protected it from the blows.

In another embodiment, electronic device20is mounted on a sheet of insulating carrier54a, such as polyimide that may have antennas56previously patterned thereon, as shown inFIG. 2a. Insulating carrier54acan be mounted on pad58to provide additional spacing for antenna56from a metal substrate, such as a pipe, to which pad58is mounted. Pad58can simply be an adhesive or it can include another layer of polyimide with layers of adhesive on either side.

Hole60ais cut in dual lock material22a, removing both mushroom stems26aand planar backing25aof first dual lock material22ain hole60a, as shown inFIG. 2b. Hole60ais sized to allow electronic device20mounted on sheet of insulating carrier54ato be inserted there through while sheet of insulating carrier54ais adhesively attached to back surface62aof planar backing25aof first dual lock material22a, as shown inFIG. 2c. Adhesive available on back surface62aof planar backing25afirst dual lock material22acan be used for this purpose.

Protective wax or butyl rubber64can be provided on electronic device20to protect electronic device20from moisture that the structure to which the package is mounted may experience, as also shown inFIG. 2c. A second layer of polyurethane material66or another such material can be used for additional shock protection.

Second dual lock material22b, with mushroom stems26bcut off or with its own hole60bis then pressed on to first dual lock material22ato form cavity68around electronic device20and to form protective package70for electronic device20, as shown inFIG. 2d. In protective package70the array of interlocking mushroom stems26a,26bsurrounding electronic device20substantially prevents transfer of impact force to electronic device20.

Protective package70is mounted to pipe72, as shown inFIG. 2e. Layer of adhesive74aprovided on back surface76aof insulating carrier54ais pressed against pipe72with driver78. Adhesive74acan be a pressure sensitive adhesive. An epoxy can also be used. Driver78includes hard layer80and soft rubber pad82to provide the force on flexible protective package70to adhere it to curved pipe72. Spray on sealant layer84, such as urethane, can then be applied, as shown inFIG. 2f.

Protective package70can be mounted to pipe72upside down, as shown inFIG. 2g. Layer of adhesive74bis provided on back surface62bof planar backing25bof second dual lock material22b. Alternatively, if insulating layer54bis provided on back surface62bof planar backing25b, layer of adhesive74bis provided on back surface76bof insulating layer54b. Spray on sealant layer84can be applied, as shown inFIG. 2h.

FIGS. 2d′,2e′,2f′,2g′, and2h′ correspond toFIGS. 2d,2e,2f,2g, and2hexcept that first and second dual lock materials22a,22bare shown pushed fully together so mushroom stems26a,26bcontact front surfaces86a,86bof corresponding planar backing25a,25bof first and second dual lock materials22a,22b. In this position mushroom stems26a,26bstrongly resist further compression of dual lock materials22a,22b, providing excellent protection to electronic device20in cavity68.

Several electronic components can be mounted using this technique. For example, active RF transceiver96, fractal antenna98, and battery100are each mounted in their own cavity102a,102b,102cwithin first and second dual lock materials22a,22bmounted on pipe72, as shown inFIG. 3. Although a single cavity can be used, the presence of interlocking mushroom stems26a,26b(seeFIGS. 2f,2h,2f′, and2h′) between each component96,98,100provides additional strength and resistance to compressive force as compared to providing all components in a single cavity.

A single dual lock material22acan also be used to provide excellent protection for electronic device20. In this embodiment, adhesive106is provided on each mushroom stem26ato adhesively connect each mushroom stem26ato pipe72, as shown inFIG. 4. While advantage from interlocking stems is not obtained, mushroom stems26astill provide substantial resistance to compressive forces, and protective package108is somewhat thinner than protective package40,40′ ofFIG. 1c,1d,FIG. 2d-2h, andFIG. 2d′-2h′ with their interlocking mushroom stems.

Dual lock material22a,22bhas 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 ribs120can be used for providing flexible packaging for a substrate with a one dimensional curvature, such as a pipe, as shown inFIG. 5a,5b.

Alternatively a two layer structure with alternating interlocking ribs122a,122bcan be used, as shown inFIG. 6a. In this embodiment, alternating interlocking ribs122a,122ballow layers124aand124bto be identical to each other. For interconnecting, layer124bmay just be displaced one row of ribs to provide mating alignment. Alternatively, two different layers can be provided, one with extensions like126aon all its ribs, the other with receptacles like126bon all its ribs.

While electronic device20is provided on insulating carrier54connected to bottom layer124bthat will be bonded to pipe72, antennas130a,130bcan be formed on second insulating carrier132that is connected to top layer124a, as shown inFIG. 6b. Pads134a,134bof conductive elastomer are provided on pads136a136bon insulating carrier54to electrically connect antennas130a,130bto electronic device20.

Other designs for surface elements can be used that still provide a flexible material. For example round extensions126aand round receptacles126b, with cross sections similar to those shown for interlocking ribs122, can replace mushroom heads on layers of flexible material, as also shown inFIG. 6a,6b, except in this caseFIG. 6a,6bare 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 latches138a,138b, as shown inFIG. 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 cap140can be provided over electronic device20to provide additional protection from blows, as shown inFIG. 8a. Hard cap140can be fabricated of a material, such as epoxy or plastic. Hard cap140′ can have openings142along its surface so gel144provided under hard cap140′ has room to leave when pressure is applied to hard cap140′ so a reduced force is transmitted to electronic device20, as shown inFIG. 8b. Gel144can 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.

InFIG. 8a′ first and second dual lock materials22a,22bare shown pushed together so mushroom stems26a,26bcontact front surfaces86a,86bof corresponding planar backing25a,25bof first and second dual lock materials22a,22b. In this position mushroom stems26a,26bstrongly resist further compression of first and second dual lock materials22a,22b, providing excellent protection to electronic device20in cavity68.

In normal use, first and second dual lock materials22a,22bmay 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 stems26a,26bcan hold dual lock materials22a,22bin one such position, such as the one shown inFIG. 1d.

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.