STRUCTURES AND METHODS RELATED TO DETECTION, SENSING, AND/OR MITIGATING UNDESIRABLE STRUCTURES OR INTRUSION EVENTS ON STRUCTURES
A method and an apparatus for mitigating electrical failures caused by intrusive structures. Such structures can be tin whiskers forming on electrical circuits. In an illustrative embodiment, nano-capsules are filled with some type of insulative and adhesive fluid that is adapted to bind to and coat an intrusive structure, e.g., a whisker, making the whisker electrically inactive and thereby reducing the electrical faults that can be caused by the whisker. In another illustrative embodiment, randomly oriented nano-fibers having an elastic modulus higher than tin or any other whisker material is used to arrest a growth or movement of a whisker and further reduce a likelihood that a whisker can cause an electrical fault.
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The present application claims priority to U.S. Provisional Patent Application Ser. No. 61/810,929, filed Apr. 11, 2013, entitled “STRUCTURES AND METHODS RELATED TO DETECTION, SENSING, AND/OR MITIGATING UNDESIRABLE STRUCTURES OR INTRUSION EVENTS ON STRUCTURES,” the disclosure of which is expressly incorporated by reference herein.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTThe invention described herein was made in the performance of official duties by employees of the Department of the Navy and may be manufactured, used and licensed by or for the United States Government for any governmental purpose without payment of any royalties thereon. This invention (Navy Case 102,519) is assigned to the United States Government and is available for licensing for commercial purposes. Licensing and technical inquiries may be directed to the Technology Transfer Office, Naval Surface Warfare Center Crane, email: Cran_CTO@navy.mil.
BACKGROUND AND SUMMARY OF THE INVENTIONThe invention relates to the sensing or detection of undesirable structures or intrusion events, such as tin whiskers, a tampering event, or an attempt to create a counterfeit device through alteration or unauthorized use of an electronic device, using a variety of structures and processing techniques. Current types of conformal coatings as applied on circuit boards are not able to prevent undesirable structure growth, such as tin or other whisker growth, through them. Furthermore, the undesirable structures that grow from current conformal coatings are problematic since they can create many short circuits and failures by conducting undesired current through them. One aspect or embodiment of the invention addresses this issue by providing a nano-fiber textile matrix above the conformal coated circuit board or by providing a conformal coat possessing a material such as a nano-fiber textile. Another embodiment of this invention utilizes encapsulating structures such as micro- or nano-tubes or micro- or nano-capsules containing a chemical fluid, such that when the undesirable structure ruptures the encapsulating structures, the fluid coats the undesirable structure with an electrically insulative layer. Thus, if the whisker emerges from the coating surface, it will have an electrically insulating coating material on its surface, rendering it electrically inactive and preventing electrical conduction.
Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.
The detailed description of the drawings particularly refers to the accompanying figures in which:
The embodiments of the invention described herein are not intended to be exhaustive or to limit the invention to precise forms disclosed. Rather, the embodiments selected for description have been chosen to enable one skilled in the art to practice the invention.
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The third layer 51 comprising a randomly or non-randomly oriented nano-fiber composite textile with elastic modulus higher than tin or any other whisker material can also act as a kind of barrier to the whisker 57. The third layer 51 can cause the whisker 57 to be deformed, bent, redirected, or to cause the movement of the whisker 57 to be slowed or stopped. Thus, the third layer 51 can act as a physical impediment to the whisker 57 and is a form of mechanical mitigation preventing the whisker 57 from creating electrical faults. The second layer 53 and third layer 51 can work together to ensure the whisker 57 does not create electrical faults by both physically preventing the whisker 57 from being able to contact other conducting materials and by coating the whisker 57 with an insulating material that causes the whisker 57 to be electrically inactive. In another embodiment of the invention, the third layer 51 can be between the first layer 52 and the second layer 53.
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In another exemplary embodiment, micro-tubes, micro-structures, or micro-capsules can be used instead of nano-tubes, nano-structures, or nano-capsules to encapsulate the insulative liquid, perform functions such as those described herein, or produce effects such as described associated with nano-scale structures described herein.
In another exemplary embodiment, the encapsulating structures, e.g., nano-capsules or nano-tubes, are provided with scribe lines or structural elements that result in a predetermined rupture or fracture in the encapsulating structure, allowing the insulative liquid contained therein to be transferred to specific locations or orientations relative to the encapsulating structure. For example, a selected portion of a wall of the encapsulating structure can be etched to form a weaker area of the encapsulating structure that is more susceptible to rupture or fracture, and thus ensure liquid is expelled in a particular direction or towards a specific location to which an intrusive structure poses a greater danger.
In another exemplary embodiment, the conformal coating comprises a tin finish or a solder coating and the layers and matrix material described above is adapted to adhere to a tin finish or solder coating.
Another exemplary embodiment can add or include a step of coating with or applying to the structures described herein (e.g., micro- or nano-tubes or micro- or nano-capsules containing insulative and adhesive liquid) some type of adhesive substance adapted to bind the structures to the conformal coating on the PCB.
An exemplary embodiment could also include use of a chemical or liquid in the tubes that can be injected into the tubes or containment structure under pressure to facilitate coating action of the chemical on the intrusive or undesirable structure. Note that a variety of embodiments of the invention can be created including alternative structures which contain the a suitable liquid or chemical which are in a structure besides a tube (e.g., box or laminate encapsulating structure), but perform the same or similar functions and provide similar multiple effects as a tube described herein e.g., multi-intrusion vector diversion, selective action, capture effects, insulator coating, capture effect, accelerant effect, etc. to name some of such effects For example, an exemplary liquid or chemical in accordance with one embodiment of the invention can also be formed within laminated or multi-walled containment structures, e.g., tubes, which have additional chemical or liquids which facilitate coating of the intrusive structures such as a material which accelerates drying or persistent coating of such intrusive structures e.g., tin whiskers.
Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the spirit and scope of the invention as described and defined in the following claims.
Claims
1. An intrusive structure mitigation system comprising:
- a plurality of first structures formed to encapsulate a liquid with insulative and adhesive properties which is formed or adapted to rupture or fracture upon a first pressure or intrusion event by a second structure and thereby enable said liquid to exit said rupture or fracture of at least one of said first structures upon occurrence of said first pressure or intrusion event; and
- a first matrix material adapted to position and bond the plurality of first structures substantially distributed through or in relation to the first matrix material;
- wherein said liquid is adapted to form an insulated coating on said second structure which intrudes or ruptures any one of said first structures thereby making at least a portion of the second structure electrically insulated from at least a portion of said second structure's environment or components said second structure comes in physical contact with or proximity with;
- wherein said first matrix material is configured to bond to a conformal coating of a third structure comprising electrical components or conductors.
2. An intrusive structure mitigation system as in claim 1, wherein said plurality of first structures comprises a plurality of capsules or a plurality of tubes that are configured to encapsulate said liquid with insulative and adhesive properties.
3. An intrusive structure mitigation system as in claim 1, further comprising a second matrix material that comprises a plurality of randomly oriented fibers adapted to have an elastic modulus higher than said second structure material so as to divert or arrest movement of said second structure so as to reduce or eliminate an electrical contact with said third structure.
4. An intrusive structure mitigation system as in claim 3, wherein the second structure comprises a tin whisker.
5. An intrusive structure mitigation system as in claim 1, wherein said plurality of first structures comprises a plurality of nano- or micro-capsules or a plurality of nano- or micro-tubes that are configured to encapsulate said liquid with insulative and adhesive properties.
6. An intrusive structure mitigation system as in claim 3, wherein the second matrix material is configured to bond to the first matrix material on a side of the first matrix material that has not bonded to the conformal coating of said third structure.
7. An intrusive structure mitigation system as in claim 3, wherein the second matrix material is configured to bond to the conformal coating of said third structure creating a physical impediment to the formation and movement of a whisker thereby reducing the likelihood that a whisker causes an electrical fault.
8. An intrusive structure mitigation system as in claim 3, wherein a third matrix material configured to receive a plurality of fourth structures formed to encapsulate said liquid with insulative and adhesive properties.
9. An intrusive structure mitigation system as in claim 8, wherein said liquid with insulative and adhesive properties is configured to rapidly bond with said second structure after an enclosing fourth structure associated with at least one of said plurality of first structures has been punctured due to interaction with a material that causes said liquid to rapidly bond with said second structure.
10. An intrusive structure mitigation system as in claim 8, wherein the third matrix material is configured to bond to the second matrix material thereby creating at least three layers of impediments or barriers to a growth or movement of said second structure and further reducing a probability that said second structure can cause an electrical fault in said third structure.
11. An intrusive structure mitigation system as in claim 1, wherein said first matrix material contains randomly oriented fiber composite textile configured or formed to have an elastic modulus higher than said second structure, wherein said second structure includes a group comprising tin or any other whisker material, wherein said first matrix material is configured to be a physical impediment to said second structure.
12. An intrusive structure mitigation structure comprising:
- a plurality of first structures comprising a wall structure completely surrounding a liquid, wherein said liquid is configured to be an electrically insulating chemical capable of forming a physical barrier to electrical conduction upon exit from said first structures and further configured to have adhesive properties; and
- a second structure comprising a first matrix material that comprises a plurality of randomly oriented fibers;
- wherein said liquid is adapted to bond to at least a third structure and thus create an insulative layer on said third structure, wherein said wall structure adapted to be frangible or rupturable such that said wall structure may be broken or fractured by said third structure when said third structure comes in contact with said wall structure and applies at least a first force to said wall structure;
- wherein said first matrix material is further adapted to have an elastic modulus higher than said third structure material so that movement of said third structure is diverted or arrested as said third structure moves into contact or within said first matrix material.
13. An intrusive structure mitigation structure as in claim 12, wherein said liquid is configured to not chemically interact or bond with the wall structure.
14. An intrusive structure mitigation structure as in claim 12, wherein said liquid is comprised of any insulative epoxy, silicone, polyurethane, polysulfide, or cyanoacrylates.
15. An intrusive structure mitigation structure as in claim 12, wherein said liquid contains two-ethylhexanoic acid adapted to bond with a tin oxide film on a whisker.
16. A method of manufacture of an intrusive structure mitigation system comprising the steps of:
- providing a plurality of first structures formed to encapsulate a liquid with insulative and adhesive properties, wherein said first structures are formed to rupture or fracture and thereby enable said liquid to exit said rupture or fracture of said first structures upon application of at least a first force to at least one of said structures;
- filling said plurality of first structure with a liquid, wherein said liquid has both electrically insulative and adhesive properties adapted to bind to a second structure thereby making the second structure electrically inactive or forming an insulative barrier on at least a portion of said second structure coming in contact with said liquid;
- dispersing the plurality of first structures into a first matrix material such that the plurality of first structures are distributed substantially evenly throughout the first matrix material;
- coating the first matrix material with some type of adhesive substance adapted to bind the first matrix material to a conformal coating of a third structure comprising at least one electrical component or section; and
- applying the first matrix material to a conformal coating of said third structure such that the first matrix material and the conformal coating adhere to one another.
17. A method of manufacture of an intrusive structure mitigation system as in claim 16 further comprising the steps of:
- providing a second matrix material made up of randomly oriented fiber composite textile having an elastic modulus higher than at least said second structure, wherein said second structure comprises at least one other material comprising tin whiskers;
- coating the second matrix material with some type of adhesive substance adapted to bind the second matrix material to the first matrix material; and
- applying the second matrix material to the first matrix material such that the two matrix materials adhere to one another.
18. A method of manufacture of an intrusive structure mitigation system as in claim 17, wherein said second matrix material is made up of orderly oriented fiber composite textile having an elastic modulus higher than at least said second structure, wherein said second structure comprises at least one other material comprising tin whiskers.
19. A method of manufacture of an intrusive structure mitigation system as in claim 16 further comprising the steps of:
- providing a second matrix material;
- mixing the second matrix material with randomly oriented fiber composite textile having an elastic modulus higher than any whisker material;
- coating the second matrix material with some type of adhesive substance adapted to bind the second matrix material to the first matrix material; and
- applying the second matrix material to the first matrix material such that the two matrix materials adhere to one another.
20. A method of manufacture of an intrusive structure mitigation system as in claim 18 further comprising the steps of:
- filling a plurality of third structures with a liquid that is electrically insulative and has adhesive properties adapted to bind to a whisker thereby making the whisker electrically inactive;
- dispersing the plurality of third structures into a matrix material such that the plurality of third structures are distributed substantially evenly throughout a third matrix material;
- coating the third matrix material with some type of adhesive substance adapted to bind the third matrix material to the second matrix material; and
- applying the third matrix material to the second matrix material such that the third matrix material and the second matrix material adhere to one another.
21. A method of manufacture of an intrusive structure mitigation system comprising the steps of:
- providing a matrix material made up of randomly oriented fiber composite textile having an elastic modulus higher than any whisker material;
- filling a plurality of first structures with a liquid that is electrically insulative and has adhesive properties adapted to bind to a whisker thereby making the whisker electrically inactive;
- dispersing said plurality of first structures into said matrix material such that said plurality of first structures are distributed substantially evenly throughout said matrix material;
- coating said matrix material with some type of adhesive substance adapted to bind said matrix material to a conformal coating of a printed circuit board (PCB); and
- applying said matrix material to said conformal coating of a PCB such that said matrix material and said conformal coating adhere to one another.
22. An intrusive structure mitigation system as in claim 1, wherein said liquid comprises silicone oils and several adhesive sealants adapted to bond to a material and render said material electrical inactive.
23. An intrusive structure mitigation system as in claim 3, wherein said second matrix material comprises orderly oriented fiber adapted to have an elastic modulus higher than said second structure material.
24. An intrusive structure mitigation structure as in claim 12, wherein said liquid is adapted to be detected by a sensor instrument such that the presence of puncturing structures can be detected.
25. An intrusive structure mitigation structure as in claim 24, wherein said liquid is further adapted with a colorant or another material such that the presence of a puncturing structure is detectable by detecting the presence of said colorant or said another material which produces a detectable predetermined electromagnetic radiation signature.
26. An intrusive structure mitigation structure as in claim 1, wherein said liquid is further adapted to comprise a material which produces a detectable electromagnetic or visual indication after said liquid exits from at least one said first structure.
27. An intrusive structure mitigation system as in claim 1, wherein said conformal coating is a coating of a printed circuit board comprising a tin finish or a solder finish.
28. An intrusive structure mitigation system as in claim 1, wherein said first matrix material comprises a plurality of randomly oriented fibers adapted to have an elastic modulus higher than said second structure material so as to divert or arrest movement of said second structure so as to reduce or eliminate an electrical contact with said third structure.
29. A method of manufacture of an intrusive structure mitigation system as in claim 16, wherein said first matrix material is made up of randomly oriented fiber composite textile having an elastic modulus higher than at least said second structure, wherein said second structure comprises at least one other material comprising tin whiskers.
Type: Application
Filed: Mar 21, 2014
Publication Date: Nov 20, 2014
Applicant: United States of America as represented by the Secretary of the Navy (Crane, IN)
Inventors: Nishkamraj U. Deshpande (Novi, MI), H. Fred Barsun (Bloomington, IN), Ron Shoultz (Crane, IN)
Application Number: 14/221,833
International Classification: H05K 1/02 (20060101); H05K 3/30 (20060101);