U.S. patent application number 15/863668 was filed with the patent office on 2019-07-11 for plastic film/sheet as replacement for typical conformal coatings.
This patent application is currently assigned to Hamilton Sundstrand Corporation. The applicant listed for this patent is Hamilton Sundstrand Corporation. Invention is credited to Robert C. Cooney, John Huss, Mark W. Metzler, Debabrata Pal, Kandy Elaine Spahr, Deron J. Staas.
Application Number | 20190215968 15/863668 |
Document ID | / |
Family ID | 67106651 |
Filed Date | 2019-07-11 |
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United States Patent
Application |
20190215968 |
Kind Code |
A1 |
Cooney; Robert C. ; et
al. |
July 11, 2019 |
PLASTIC FILM/SHEET AS REPLACEMENT FOR TYPICAL CONFORMAL
COATINGS
Abstract
A system for protecting electronics includes a printed wiring
assembly (PWA) having a surface with at least one electronic
component. The system also includes a water resistant film
configured to be used as a conformal coating on the PWA and further
configured to be placed on the surface of the PWA and to shrink
about the at least one electronic component.
Inventors: |
Cooney; Robert C.;
(Janesville, WI) ; Huss; John; (Roscoe, IL)
; Spahr; Kandy Elaine; (Roscoe, IL) ; Staas; Deron
J.; (Rockford, IL) ; Metzler; Mark W.; (Davis,
IL) ; Pal; Debabrata; (Hoffman Estates, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hamilton Sundstrand Corporation |
Charlotte |
NC |
US |
|
|
Assignee: |
Hamilton Sundstrand
Corporation
Charlotte
NC
|
Family ID: |
67106651 |
Appl. No.: |
15/863668 |
Filed: |
January 5, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05K 2201/0125 20130101;
H05K 2203/1333 20130101; H05K 2201/0108 20130101; H05K 3/285
20130101; H05K 3/281 20130101; H05K 2201/0129 20130101; H05K 3/0044
20130101; H05K 1/181 20130101; H05K 3/284 20130101 |
International
Class: |
H05K 3/28 20060101
H05K003/28; H05K 1/18 20060101 H05K001/18; H05K 3/00 20060101
H05K003/00 |
Claims
1. A system for protecting electronics, comprising: a printed
wiring assembly (PWA) having a surface with at least one electronic
component; and a water resistant film separate from the PWA, being
cut to a desired shape to contact the PWA at locations in which a
conformal coating is desired and to avoid contacting the PWA at
other locations, providing the conformal coating on the PWA,
located on the surface of the PWA, and shrunk about the at least
one electronic component and the PWA to couple the water resistant
film to the at least one electronic component and the PWA.
2. The system of claim 1 wherein the film is capable of holding an
electric charge to facilitate a static cling of the film to the PWA
to resist movement of the film relative to the PWA prior to
shrinking.
3. The system of claim 1, further comprising an adhesive positioned
between the film and the PWA to resist movement of the film
relative to the PWA prior to shrinking of the film.
4. The system of claim 3, wherein the adhesive includes at least
one of acrylic or polyamide.
5. The system of claim 1, wherein the film is provided as multiple
strips configured to be positioned adjacent to each other on the
PWA prior to shrinking.
6. The system of claim 1, wherein the film is transparent or
semi-transparent to facilitate viewing of the at least one
electronic component in response to the film being coupled to the
PWA.
7. The system of claim 1, wherein the film operates as an
electrical insulator.
8. The system of claim 1, wherein the film is sufficiently flexible
to surround and contact all exposed surfaces of the at least one
electronic component in response to the film being shrunk.
9. The system of claim 1, wherein the film is shrunk by being
heated to or above a selected temperature.
10. The system of claim 1, wherein the film has a thickness between
1 thousandth of an inch (0.025 millimeters) and 10 thousandths of
an inch (0.25 millimeters).
11. (canceled)
12. The system of claim 1, wherein the film includes a
thermoplastic.
13. The system of claim 1, wherein the film is provided as a single
sheet sufficiently large to contact the PWA at all locations in
which the conformal coating is desired.
14. A system for protecting electronics, comprising: a printed
wiring assembly (PWA) having a surface with at least one electronic
component; and a water resistant film separate from the PWA, being
cut to a desired shape to contact the PWA at locations in which a
conformal coating is desired and to avoid contacting the PWA at
other locations, providing the conformal coating for the PWA, and
coupled to the surface of the PWA via heat-shrinking the film about
the PWA to reduce a likelihood of water damage to the PWA.
15. The system of claim 14, wherein the film is transparent or
semi-transparent to facilitate viewing of the at least one
electronic component in response to the film being coupled to the
PWA and operates as an electrical insulator.
16. A method for protecting electronics, comprising: placing a
water resistant film over at least one electronic component on a
surface of a printed wiring assembly (PWA); cutting the film to a
desired shape before placing the film over the surface of the PWA
such that the film contacts the PWA at locations in which conformal
coating is desired and avoids contacting the PWA at other
locations; and shrinking the film about the PWA to couple the film
to the at least one electronic component.
17. (canceled)
18. The method of claim 16, further comprising fastening the film
to the surface via an adhesive, wherein shrinking the film about
the PWA includes heating the film.
19. The method of claim 16, wherein the film includes at least one
of polyvinylidene fluoride, flexible crosslinked polyolefin,
flexible fluoroelastomer, or polyether ether ketone (PEEK).
20. The method of claim 16, wherein the film is sufficiently
flexible to surround and contact all exposed surfaces of the at
least one electronic component in response to the film being
coupled to the PWA.
Description
FIELD
[0001] The present disclosure is directed to systems and methods
for protecting electronics by covering at least a portion of a
printed wiring assembly with a film that functions as a conformal
coating.
BACKGROUND
[0002] Printed wiring assemblies (PWAs) may include multiple
electronic components positioned on a surface thereof. A PWA may
further include wire traces or other conductors that couple the
multiple electronic components together. The PWA may also include
solder joints at locations in which the electronic components are
coupled to the conductors.
[0003] Some PWAs may be used in locations in which they may be
exposed to moisture. Many electronics and conductors may be damaged
by moisture, so it may be desirable to protect the PWA and
associated components from being exposed to such moisture.
SUMMARY
[0004] Described herein is a system for protecting electronics. The
system includes a printed wiring assembly (PWA) having a surface
with at least one electronic component. The system also includes a
water resistant film configured to be used as a conformal coating
on the PWA and further configured to be placed on the surface of
the PWA and to shrink about the at least one electronic
component.
[0005] In any of the foregoing embodiments, the film may be capable
of holding an electric charge (such as a very low level electric
charge) to facilitate a static cling of the film to the PWA to
resist movement of the film relative to the PWA prior to
shrinking.
[0006] Any of the foregoing embodiments may also include an
adhesive configured to be positioned between the film and the PWA
to resist movement of the film relative to the PWA prior to
shrinking.
[0007] In any of the foregoing embodiments, the adhesive includes
at least one of acrylic or polyamide.
[0008] In any of the foregoing embodiments, the film is provided as
multiple strips configured to be positioned adjacent to each other
on the PWA prior to shrinking.
[0009] In any of the foregoing embodiments, the film is transparent
or semi-transparent to facilitate viewing of the at least one
electronic component in response to the film being coupled to the
PWA.
[0010] In any of the foregoing embodiments, the film operates as an
electrical insulator.
[0011] In any of the foregoing embodiments, the film is
sufficiently flexible to surround and contact all exposed surfaces
of the at least one electronic component in response to the film
being coupled to the PWA.
[0012] In any of the foregoing embodiments, the film is configured
to shrink in response to being heated to or above a selected
temperature.
[0013] In any of the foregoing embodiments, the film has a
thickness between 1 thousandth of an inch (0.025 millimeters) and
10 thousandths of an inch (0.25 millimeters). It is desirable to
minimize the thickness of the film in order to reduce thermal
resistance between the PWA and any ambient cooling fluid.
[0014] In any of the foregoing embodiments, the film is cut to a
desired shape to contact the PWA at locations in which the
conformal coating is desired and to avoid contacting the PWA at
other locations.
[0015] In any of the foregoing embodiments, the film includes a
thermoplastic.
[0016] In any of the foregoing embodiments, the film is provided as
a single sheet sufficiently large to contact the PWA at all
locations in which the conformal coating is desired.
[0017] Also disclosed is a system for protecting electronics. The
system includes a printed wiring assembly (PWA) having a surface
with at least one electronic component. The system also includes a
water resistant film for use as a conformal coating for the PWA and
coupled to the surface of the PWA via heat-shrinking the film about
the PWA to reduce a likelihood of water damage to the PWA.
[0018] In any of the foregoing embodiments, the film is transparent
or semi-transparent to facilitate viewing of the at least one
electronic component in response to the film being coupled to the
PWA and operates as an electrical insulator.
[0019] In any of the foregoing embodiments, the film has a
thickness between 1 thousandth of an inch (0.025 millimeters) and
10 thousandths of an inch (0.25 millimeters).
[0020] Also disclosed is a method for protecting electronics. The
method includes placing a water resistant film over at least one
electronic component on a surface of a printed wiring assembly
(PWA). The method also includes shrinking the film about the PWA to
couple the film to the at least one electronic component
[0021] Any of the foregoing embodiments may also include cutting
the film to a desired shape before placing the film over the
surface of the PWA such that the film contacts the PWA at locations
in which conformal coating is desired and avoids contacting the PWA
at other locations.
[0022] Any of the foregoing embodiments may also include fastening
the film to the surface via an adhesive, wherein shrinking the film
about the PWA includes heating the film.
[0023] In any of the foregoing embodiments, the film includes at
least one of polyvinylidene fluoride, flexible crosslinked
polyolefin, flexible fluoroelastomer, or polyether ether ketone
(PEEK).
[0024] In any of the foregoing embodiments, the film is
sufficiently flexible to surround and contact all exposed surfaces
of the at least one electronic component in response to the film
being coupled to the PWA. It is desirable for the coefficient of
thermal expansion of the film to match that of the PWA over
operational range of temperatures, such as between negative 40
degrees C. and 110 degrees C.
[0025] The forgoing features and elements may be combined in
various combinations without exclusivity, unless expressly
indicated herein otherwise. These features and elements as well as
the operation of the disclosed embodiments will become more
apparent in light of the following description and accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The subject matter of the present disclosure is particularly
pointed out and distinctly claimed in the concluding portion of the
specification. A more complete understanding of the present
disclosures, however, may best be obtained by referring to the
detailed description and claims when considered in connection with
the drawing figures, wherein like numerals denote like
elements.
[0027] FIG. 1A illustrates a top-down view of a printed wiring
assembly (PWA), in accordance with various embodiments of the
present disclosure;
[0028] FIG. 1B illustrates a side view of the PWA of FIG. 1A, in
accordance with various embodiments of the present disclosure;
[0029] FIG. 2A illustrates a top-down view of a system for
protecting the PWA of FIG. 1 including a film to be coupled to the
PWA, in accordance with various embodiments of the present
disclosure,
[0030] FIG. 2B illustrates a side view of the system of FIG. 2A, in
accordance with various embodiments of the present disclosure;
[0031] FIG. 3A illustrates an electronic component and the film of
FIGS. 2A and 2B prior to coupling the film to the electronic
component, in accordance with various embodiments of the present
disclosure;
[0032] FIG. 3B illustrates the electronic component and the film of
FIG. 3A after heating the film to cause the film to shrink about
the electronic component, in accordance with various embodiments of
the present disclosure;
[0033] FIG. 4 illustrates a system for protecting an electronic
component and includes a PWA, a film, and an adhesive used to
couple the film to the PWA, in accordance with various embodiments
of the present disclosure; and
[0034] FIG. 5 illustrates a film for use in protecting a PWA that
includes multiple strips, in accordance with various embodiments of
the present disclosure.
DETAILED DESCRIPTION
[0035] The detailed description of exemplary embodiments herein
makes reference to the accompanying drawings, which show exemplary
embodiments by way of illustration and their best mode. While these
exemplary embodiments are described in sufficient detail to enable
those skilled in the art to practice the disclosure, it should be
understood that other embodiments may be realized and that logical,
chemical, and mechanical changes may be made without departing from
the spirit and scope of the disclosure. Thus, the detailed
description herein is presented for purposes of illustration only
and not of limitation. For example, the steps recited in any of the
method or process descriptions may be executed in any order and are
not necessarily limited to the order presented. Furthermore, any
reference to singular includes plural embodiments, and any
reference to more than one component or step may include a singular
embodiment or step. Also, any reference to attached, fixed,
connected or the like may include permanent, removable, temporary,
partial, full and/or any other possible attachment option.
Additionally, any reference to without contact (or similar phrases)
may also include reduced contact or minimal contact.
[0036] Referring to FIGS. 1A and 1B, a printed wiring assembly
(PWA) 100 includes a surface 102 with at least one exposed
electronic component 104 positioned thereon. For example, the PWA
100 may include a power component 106, a first connector 108, and a
second connector 110. The second connector 110 may include a first
portion 112 and a second portion 114. The PWA 100 may further
include a first guide rail 116 and a second guide rail 118. The PWA
100 may include printed traces or other conductors that connect one
or more of the electronic components together, along with solder
joints that connect the electronic components 104 to the printed
traces or other conductors. In various embodiments, the printed
traces may be located on the surface 102.
[0037] Because the PWA 100 includes electronic devices and
electronic connectors (i.e., traces and solder joints), it may be
desirable to protect the surface 102 of the PWA 100, along with a
portion of the at least one exposed electronic component 104, from
water exposure. In that regard and referring to FIGS. 2A and 2B, a
system 250 for protecting electronics includes the PWA 100 and a
film 200 designed to be coupled to the PWA 100. In particular, the
film 200 may be positioned on the surface 102 and may cover a
portion of or all the at least one exposed electronic component
104.
[0038] The film 200 may include water resistant properties such
that the film 200 reduces the likelihood of water contacting the
portions of the PWA 100 that are covered by the film 200 in
response to the film 200 being coupled to the PWA 100. In that
regard, the film 200 may function as a conformal coating to form a
barrier to reduce the likelihood of ingress of moisture to the
electronic components 104, the traces, and the solder joints of the
PWA 100.
[0039] It may be desirable for the PWA 100 to be relatively dry
prior to being coupled to the film 200. This is because moisture on
the surface 102 of the PWA 100 may become trapped between the PWA
100 and the film 200. In that regard, it may be desirable for the
PWA 100 to be at least one of stored in a dry box, subjected to a
vacuum, or subjected to purging of moisture from the PWA 100, such
as via purging with dry nitrogen prior to the film 200 being
coupled thereto.
[0040] In various embodiments, the film 200 may include a
thermoplastic. For example, the film 200 may include at least one
of polyvinylidene fluoride, flexible crosslinked polyolefin,
flexible fluoroelastomer, or polyether ether ketone (PEEK).
[0041] In various embodiments, it may be desirable for the film 200
to be sufficiently flexible to surround and contact all exposed
surfaces of the electronic components 104 in response to the film
200 being coupled to the PWA 100. It may also be desirable for the
coefficient of thermal expansion of the film to match that of the
PWA over operational range of temperatures, such as between
negative 40 degrees C. and 110 degrees C.
[0042] The film 200 may have a thickness 204. In various
embodiments, the thickness 204 may be between 0.1 thousandths of an
inch (0.1 mils, 0.0025 millimeters (0.0025 mm)) and 50 mils (1.27
mm), between 0.5 mils (0.13 mm) and 25 mils (0.64 mm), or between 1
mil (0.025 mm) and 10 mils (0.25 mm). It is desirable to minimize
the thickness 204 of the film in order to reduce thermal resistance
between the PWA 100 and any ambient cooling fluid.
[0043] In particular and referring to FIGS. 1A, 1B, 2A, and 2B, it
may be desirable to cover the entire power component 106, the
entire first connector 108, and the second portion 114 of the
second connector 110 with the film 200. It may be desirable to
leave the first portion 112 of the second connector 110 exposed,
along with the first guide rail 116 and the second guide rail 118.
In that regard, the film 200 may be cut to a desired shape in order
to contact or cover the PWA 100 at locations in which a conformal
coating is desired, and to avoid contacting the PWA 100 at other
locations. In particular, the film 200 may be cut in such a way as
to cover the power component 106, the desirable portion of the
surface 102, and the second portion 114 of the second connector
110. Additionally, a second piece of film 201 may be cut in such a
way as to cover the first connector 108.
[0044] The film 200 may be designed to shrink around the PWA 100 in
order to couple the film 200 to the PWA 100. For example and
referring to FIG. 3A, the film 201 may be provided in a size that
is greater than the surface area of the first connector 108 prior
to heating the film 201. After being positioned about the first
connector 108, the film 201 may be heated. Turning to FIG. 3B and
as the film 201 is heated, the film 201 may shrink to match the
surface area of the first connector 108. In response to the film
201 being shrunk about the first connector 108, the film 201 may be
coupled to the first connector 108.
[0045] In various embodiments, it may be desirable for the material
of the film 201 to be bondable to the PWA 100. For example, it may
be desirable for the material of the film 201 to facilitate bonding
of the film 201 to the PWA 100, such as in response to heat being
applied to the film 201, an adhesive being applied between the film
201 and the PWA 100, or the like.
[0046] In various embodiments, the film 201 may be designed to
shrink in response to being heated to or above a predetermined or
selected temperature. In various embodiments, the predetermined or
selected temperature may be between 150 degrees Fahrenheit (150
degrees F., 65.6 degrees Celsius (65.6 degrees C.)) and 700 degrees
F. (371 degrees C.), between 150 degrees F. (65.6 degrees C.) and
500 degrees C. (260 degrees C.), or between 200 degrees F. (93
degrees C.) and 400 degrees F. (204 degrees C.).
[0047] In various embodiments and returning reference to FIGS. 2A
and 2B, it may be desirable for a user to view the components of
the PWA 100 after the film 200 has been coupled to the PWA 100. In
that regard, the film 200 may be transparent or semi-transparent
(such as translucent) to facilitate viewing of the components of
the PWA 100.
[0048] In various embodiments, one or more of the exposed
electronic components 104 of the PWA 100 may occasionally fail. For
example and referring to FIGS. 1A, 1B, 2A, and 2B, the power
component 106 may fail after significant use. A user of the PWA 100
may view the power component 106 through the transparent or
semi-transparent film 200 to identify that the power component 106
has failed. The user may then cut out a portion 206 of the film 200
to replace the power component 106. The user may then couple a new
piece of film to the area of the PWA 100 exposed by removal of the
portion 206 to cover the replacement power component 106. The new
piece of film may be coupled to the area of the PWA 100 via heat
shrinking, an adhesive, or the like. In various embodiments, a
liquid conformal coating may be used to patch the area of the PWA
100 that is exposed by removal of the portion 206 instead of, or in
addition to, coupling the new piece of film to the area exposed by
removal of the portion 206.
[0049] Because the film 200 may contact more than one electronic
component 104, it may be desirable for the film 200 to be
nonconductive. In that regard, the material of the film 200 may
function or operate as an electrical insulator and may thus be
nonconductive.
[0050] In various embodiments, one or more of the exposed
electronic components 104 may extend away from the surface 102. In
that regard, the film 200 may have sufficient flexibility to
surround and contact all exposed surfaces of the exposed electronic
components 104 that are to be covered with the film 200.
[0051] In various embodiments, it may be desirable to cause the
film 200 to remain in place relative to the PWA 100 prior to
shrinking the film 200 about the PWA 100. In that regard, the film
200 may be capable of holding an electric charge to facilitate a
static cling of the film 200 to the PWA 100. A user may place the
film 200 with a static charge in the desirable location on the
surface 102. The static charge of the film 200 may cause the film
200 to remain in place relative to the PWA 100 during any transport
of the system 250 and prior to or during heating of the film
200.
[0052] In various embodiments and referring to FIG. 4, a system 400
for protecting electronics may include a PWA 402 having one or more
electronic component 404. The system 400 may further include a film
406. Unlike the film 200 of FIGS. 2A and 2B, the film 406 may fail
to include a static charge. In that regard, an adhesive 408 may be
located between the film 406 and the PWA 402. The adhesive 408 may
resist movement of the film 406 relative to the PWA 402 prior to
shrinking of the film 406. In various embodiments, the adhesive 408
may include at least one of acrylic or polyamide.
[0053] In various embodiments and referring to FIGS. 1A and 5, a
film 500 may be provided as multiple strips 501. Each of the
multiple strips 501 may be placed adjacent to each other on the
surface 102 of the PWA 100. For example, a first strip 502 may be
positioned on a first portion 120 of the surface 102, a second
strip 504 may be positioned on a second portion 122 of the surface
102, and a third strip 506 may be positioned on a third portion 124
of the surface 102.
[0054] In various embodiments, one or more of the multiple strips
501 may have a width that corresponds to a width of an electronic
component on which the film 500 will be positioned. For example,
the first strip 502 may have a width 508. The width 508 may be
similar to, or the same as, a width 126 of the power component 106.
In that regard, use of the multiple strips 501 may increase the
ease of positioning the film 500 around outer surfaces of the
exposed electronic components 104.
[0055] Benefits, other advantages, and solutions to problems have
been described herein with regard to specific embodiments.
Furthermore, the connecting lines shown in the various figures
contained herein are intended to represent exemplary functional
relationships and/or physical couplings between the various
elements. It should be noted that many alternative or additional
functional relationships or physical connections may be present in
a practical system. However, the benefits, advantages, solutions to
problems, and any elements that may cause any benefit, advantage,
or solution to occur or become more pronounced are not to be
construed as critical, required, or essential features or elements
of the disclosure. The scope of the disclosure is accordingly to be
limited by nothing other than the appended claims, in which
reference to an element in the singular is not intended to mean
"one and only one" unless explicitly so stated, but rather "one or
more." Moreover, where a phrase similar to "at least one of A, B,
or C" is used in the claims, it is intended that the phrase be
interpreted to mean that A alone may be present in an embodiment, B
alone may be present in an embodiment, C alone may be present in an
embodiment, or that any combination of the elements A, B and C may
be present in a single embodiment; for example, A and B, A and C, B
and C, or A and B and C. Different cross-hatching is used
throughout the figures to denote different parts but not
necessarily to denote the same or different materials.
[0056] Systems, methods and apparatus are provided herein. In the
detailed description herein, references to "one embodiment", "an
embodiment", "an example embodiment", etc., indicate that the
embodiment described may include a particular feature, structure,
or characteristic, but every embodiment may not necessarily include
the particular feature, structure, or characteristic. Moreover,
such phrases are not necessarily referring to the same embodiment.
Further, when a particular feature, structure, or characteristic is
described in connection with an embodiment, it is submitted that it
is within the knowledge of one skilled in the art to affect such
feature, structure, or characteristic in connection with other
embodiments whether or not explicitly described. After reading the
description, it will be apparent to one skilled in the relevant
art(s) how to implement the disclosure in alternative
embodiments.
[0057] Furthermore, no element, component, or method step in the
present disclosure is intended to be dedicated to the public
regardless of whether the element, component, or method step is
explicitly recited in the claims. No claim element herein is to be
construed under the provisions of 35 U.S.C. 112(f) unless the
element is expressly recited using the phrase "means for." As used
herein, the terms "comprises", "comprising", or any other variation
thereof, are intended to cover a non-exclusive inclusion, such that
a process, method, article, or apparatus that comprises a list of
elements does not include only those elements but may include other
elements not expressly listed or inherent to such process, method,
article, or apparatus.
* * * * *