U.S. patent application number 15/912291 was filed with the patent office on 2018-07-12 for insulated conductive strands with polymer cores.
The applicant listed for this patent is Apple Inc.. Invention is credited to Kathryn P. Crews, Yohji Hamada, John Arthur Maasberg, Kirk M. Mayer, Daniel A. Podhajny, Daniel D. Sunshine.
Application Number | 20180195210 15/912291 |
Document ID | / |
Family ID | 56134557 |
Filed Date | 2018-07-12 |
United States Patent
Application |
20180195210 |
Kind Code |
A1 |
Sunshine; Daniel D. ; et
al. |
July 12, 2018 |
Insulated Conductive Strands With Polymer Cores
Abstract
An item may include fabric or other materials formed from
intertwined strands of material. The item may include circuitry
that produces signals. The strands of material may include
non-conductive strands and conductive strands. The non-conductive
strands and conductive strands may be close in size. The conductive
strands may carry the signals produced by the circuitry. Each
conductive strand may have a strand core, a conductive coating on
the strand core, and an insulating coating on the conductive
coating. The strand cores may be strands formed from polymer. The
conductive coating may be formed from metal. The insulating coating
may have a relatively thin thickness and may be formed from a
polymer.
Inventors: |
Sunshine; Daniel D.;
(Sunnyvale, CA) ; Podhajny; Daniel A.; (San Jose,
CA) ; Maasberg; John Arthur; (Berkeley, CA) ;
Crews; Kathryn P.; (Menlo Park, CA) ; Mayer; Kirk
M.; (San Francisco, CA) ; Hamada; Yohji;
(Wakayama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Apple Inc. |
Cupertino |
CA |
US |
|
|
Family ID: |
56134557 |
Appl. No.: |
15/912291 |
Filed: |
March 5, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15578196 |
Nov 29, 2017 |
|
|
|
PCT/US2016/031646 |
May 10, 2016 |
|
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15912291 |
|
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62170630 |
Jun 3, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D10B 2401/16 20130101;
D02G 3/441 20130101; D03D 1/0088 20130101; D10B 2401/18
20130101 |
International
Class: |
D02G 3/44 20060101
D02G003/44; D03D 1/00 20060101 D03D001/00 |
Claims
1. Intertwined strands of material, comprising: non-conductive
strands; and conductive strands that are intertwined with the
non-conductive strands, wherein each conductive strand has a strand
core, a conductive coating on the strand core, and an insulating
coating on the conductive core.
2. The intertwined strands of material defined in claim 1 wherein
the strand core of each conductive strand comprises a dielectric
material.
3. The intertwined strands of material defined in claim 2 wherein
the strand core of each conductive strand comprises a polymer.
4. The intertwined strands of material defined in claim 3 wherein
the polymer is selected from the group consisting of: polyamide,
aromatic polyamide, polyimide, polyester, polyolefin, acrylic,
aromatic polyesters, polyethylene, cellulosic polymer, and
polyurethane.
5. The intertwined strands of material defined in claim 3 wherein
the polymer is a para-aramid.
6. The intertwined strands of material defined in claim 3 wherein
the polymer is an aromatic polyester.
7. The intertwined strands of material defined in claim 1 wherein
the conductive coating comprises metal and wherein the strand core
has a linear mass density of less than 100 denier.
8. The intertwined strands of material defined in claim 7 wherein
the conductive coating comprises silver.
9. The intertwined strands of material defined in claim 8 wherein
the insulating coating comprises a polymer coating having a
thickness of less than 5 microns.
10. The intertwined strands of material defined in claim 1 wherein
the insulating coating comprises a polymer material selected from
the group consisting of: polyvinyl formal, polyester-polyimide,
polyamide-polyimide, polyamide, polyimide, polyester,
polytetrafluoroethylene, and polyurethane.
11. The intertwined strands of material defined in claim 10 wherein
the conductive coating is a metal coating.
12. The intertwined strands of material defined in claim 11 wherein
the strand core comprises a material selected from the group
consisting of: para-aramid and polyester.
13. The intertwined strands of material defined in claim 12 wherein
the insulating coating has a thickness of less than 5 microns.
14. The intertwined strands of material defined in claim 13 wherein
the metal coating comprises silver.
15. The intertwined strands of material defined in claim 14 wherein
the non-conductive strands have a first diameter, wherein the
conductive strands have a second diameter, and wherein the second
diameter is within 30% of the first diameter.
16. The intertwined strands of material defined in claim 1 wherein
the non-conductive strands have a first diameter, wherein the
conductive strands have a second diameter, and wherein the second
diameter is within 50% of the first diameter.
17. The intertwined strands of material defined in claim 16 wherein
the strand core of each conductive strand is a polymer strand,
wherein the conductive coating of each conductive strand is a metal
coating, and wherein the insulating coating of each conductive
strand has a thickness of less than 3 microns.
18. A fabric-based item, comprising: circuitry; and intertwined
strands of material including conductive strands that carry signals
for the circuitry and non-conductive strands, wherein the
conductive strands each have a polymer strand core, a metal coating
on the polymer strand core, and an insulating coating on the metal
coating.
19. The fabric-based item defined in claim 18 wherein the
insulating coating has a thickness of less than 5 microns.
20. The fabric-based item defined in claim 19 wherein the
insulating coating comprises a material selected from the group
consisting of: polyvinyl formal, polyester-polyimide,
polyamide-polyimide, polyamide, polyimide, polyester,
polytetrafluoroethylene, and polyurethane.
21. The fabric-based item defined in claim 20 wherein the
conductive coating comprises metal and wherein the strand core has
a linear mass density of less than 100 denier.
22. A fabric-based item, comprising: electrical components that
produce signals; and fabric that includes non-conductive strands
and conductive strands, wherein the conductive strands carry the
signals and wherein each conductive strand has a polymer strand
core with a linear mass density of less than 100 denier, a metal
coating on the polymer strand core, and an insulating coating with
a thickness of less than 5 microns on the metal coating.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/578, 196, filed Nov. 29, 2017, which is a
371 of international patent application No. PCT/US2016/031646,
filed May 10, 2016, which claims priority to provisional patent
application No. 62/170,630, filed Jun. 3, 2015, which are hereby
incorporated by reference herein in their entireties.
BACKGROUND
[0002] This relates generally to items formed from strands of
material, and, more particularly, to items formed from strands of
material such as insulated conductive strands with dielectric
cores.
[0003] It may be desirable to form items such a bags, clothing, and
other items from intertwined strands of material. For example,
woven or knitted fabric or braided strands may be used in forming
portions of an item.
[0004] In some situations, may be desirable for some or all of a
strand of material in an item to be conductive. Conductive strands
may be used, for example, to carry signals between circuitry in
different portions of an item. Strands such as conductive strands
may serve both mechanical functions (e.g., by forming a part of a
fabric) and/or electrical functions (e.g., by conveying
signals).
[0005] Challenges may arise when forming items such as fabric-based
items with conductive strands. It is often desirable for conductive
strands to exhibit good mechanical properties, such as high
strength and flexibility. Because conductive strands may need to
carry electrical signals, the resistance of a conductive strand
should generally not be too high. Conductive strands should also be
compatible with the non-conductive strands in a fabric and should
not form undesired short circuits with surrounding structures. If
care is not taken, conductive strands in a fabric-based item may be
overly fragile, may exhibit poor signal carrying capabilities, may
be insufficiently isolated from surrounding structures, or may
adversely affect the appearance and feel of the item.
[0006] It would therefore be desirable to be able to provide
strand-based items that incorporate improved conductive
strands.
SUMMARY
[0007] An item may include fabric or other materials formed from
intertwined strands of material. The item may include circuitry
that produces signals. The strands of material may include
non-conductive strands and conductive strands. Strands may be
intertwined using weaving equipment, knitting equipment, braiding
equipment, or other equipment for intertwining strands of material.
If desired, the non-conductive strands and conductive strands may
be close in size (e.g., to minimize or eliminate perceptible
differences in the appearance and feel of the non-conductive and
conductive strands).
[0008] The conductive strands may carry the signals produced by the
circuitry. Each conductive strand may have a strand core, a
conductive coating on the strand core, and an insulating coating on
the conductive coating. The strand cores may be formed from
polymers such as para-aramids and aromatic polyesters (as
examples). The conductive coating may be formed from a metal such
as silver or other metals. The insulating coating may be a
relatively thin insulator such as an insulator with a thickness of
less than 5 microns or other suitable thickness. Examples of
materials that may be used for forming the insulator include
polyvinyl formal, polyester-polyimide, polyamide-polyimide,
polyamide, polyimide, polyester, polytetrafluoroethylene,
polyurethane, and other polymers.
[0009] Polymer strand cores may be formed by extrusion, spinning,
or other techniques. Metal coatings for the strand cores may be
formed by electrochemical deposition or other metal deposition
techniques. Insulating coatings may be formed by applying liquid
polymer in a thin layer to the exterior of a strand that has been
coated with metal and by applying heat or otherwise curing the
liquid polymer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic diagram of an illustrative
strand-based item in accordance with an embodiment.
[0011] FIG. 2 is a diagram of a portion of a fabric with conductive
strands in accordance with an embodiment.
[0012] FIG. 3 is a diagram of illustrative equipment of the type
that may be used in forming insulated conductive strands with
dielectric cores and strand-based items that include insulated
conductive strands with dielectric cores in accordance with an
embodiment.
[0013] FIG. 4 is a side view of illustrative equipment for forming
a dielectric core and coating the core with a conductive material
such as metal for a strand in accordance with an embodiment.
[0014] FIG. 5 is a side view of illustrative equipment for adding
an insulating coating to a conductive strand in accordance with an
embodiment.
[0015] FIG. 6 is a cross-sectional view of a dielectric strand core
in accordance with an embodiment.
[0016] FIG. 7 is a cross-sectional view of a strand having a
dielectric core and a conductive coating layer in accordance with
an embodiment.
[0017] FIG. 8 is a cross-sectional view of a strand having a
dielectric core, a conductive coating, and an insulating coating in
accordance with an embodiment.
[0018] FIG. 9 is a flow chart of illustrative steps involved in
forming conductive strands with dielectric cores and insulating
coatings and in forming strand-based items from such strands in
accordance with an embodiment.
DETAILED DESCRIPTION
[0019] Strands of material may be incorporated into strand-based
items such as strand-based item 10 of FIG. 1. Item 10 may be an
electronic device or an accessory for an electronic device such as
a laptop computer, a computer monitor containing an embedded
computer, a tablet computer, a cellular telephone, a media player,
or other handheld or portable electronic device, a smaller device
such as a wrist-watch device, a pendant device, a headphone or
earpiece device, a device embedded in eyeglasses or other equipment
worn on a user's head, or other wearable or miniature device, a
television, a computer display that does not contain an embedded
computer, a gaming device, a navigation device, an embedded system
such as a system in which fabric-based item 10 is mounted in a
kiosk, in an automobile, airplane, or other vehicle, other
electronic equipment, or equipment that implements the
functionality of two or more of these devices. If desired, item 10
may be a removable external case for electronic equipment, may be a
strap, may be a wrist band or head band, may be a removable cover
for a device, may be a case or bag that has straps or that has
other structures to receive and carry electronic equipment and
other items, may be a necklace or arm band, may be a wallet,
sleeve, pocket, or other structure into which electronic equipment
or other items may be inserted, may be part of a chair, sofa, or
other seating (e.g., cushions or other seating structures), may be
part of an item of clothing or other wearable item (e.g., a hat,
belt, wrist band, headband, etc.), or may be any other suitable
strand-based item.
[0020] Strands in strand-based item 10 may form all or part of a
housing wall for an electronic device, may form internal structures
in an electronic device, or may form other strand-based structures.
Strand-based item 10 may be soft (e.g., item 10 may have a fabric
surface that yields to a light touch), may have a rigid feel (e.g.,
the surface of item 10 may be formed from a stiff fabric), may be
coarse, may be smooth, may have ribs or other patterned textures,
and/or may be formed as part of a device that has portions formed
from non-fabric structures of plastic, metal, glass, crystalline
materials, ceramics, or other materials.
[0021] Item 10 may include intertwined strands 12. The strands may
be intertwined using strand intertwining equipment such as weaving
equipment, knitting equipment, braiding equipment, or equipment
that intertwines strands by entangling the strands with each other
in other ways (e.g., to form felt). Intertwined strands 12 may, for
example, form woven or knitted fabric or other fabric (i.e., item
10 may be a fabric-based item), a braided cord, etc.
[0022] Strands 12 may be single-filament strands or may be threads,
yarns, or other strands that have been formed by intertwining
multiple filaments of material together. Strands 12 may be formed
from polymer, metal, glass, graphite, ceramic, natural fibers such
as cotton, bamboo, wool, or other organic and/or inorganic
materials and combinations of these materials. Strands 12 may be
insulating or conductive.
[0023] Conductive coatings such as metal coatings may be formed on
non-conductive strands (e.g., plastic cores) to make them
conductive and strands such as these may be coated with insulation
or left bare. Reflective coatings such as metal coatings may be
applied to strands 12 to make them reflective. Strands 12 may also
be formed from single-filament metal wire, multifilament wire, or
combinations of different materials.
[0024] Strands 12 may be conductive along their entire length or
may have conductive segments (e.g., metal portions that are exposed
by locally removing insulation or that are formed by adding a
conductive layer to a portion of a non-conductive strand.). Threads
and other multifilament yarns that have been formed from
intertwined filaments may contain mixtures of conductive fibers and
insulating fibers (e.g., metal strands or metal coated strands with
or without exterior insulating layers may be used in combination
with solid plastic fibers or natural fibers that are
insulating).
[0025] Item 10 may include additional mechanical structures 14 such
as polymer binder to hold strands 12 together, support structures
such as frame members, housing structures (e.g., an electronic
device housing), and other mechanical structures.
[0026] Circuitry 16 may be included in item 10. Circuitry 16 may
include components that are coupled to strands 12, components that
are housed within an enclosure formed by strands 12, components
that are attached to strands 12 using welds, solder joints,
adhesive bonds (e.g., conductive adhesive bonds), crimped
connections, or other electrical and/or mechanical bonds. Circuitry
16 may include metal structures for carrying current, integrated
circuits, discrete electrical components such as resistors,
capacitors, and inductors, switches, connectors, light-emitting
components such as light-emitting diodes, audio components such as
microphones and speakers, vibrators, solenoids, piezoelectric
devices, and other electromechanical devices, connectors,
microelectromechanical systems (MEMs) devices, pressure sensors,
light detectors, proximity sensors, force sensors, moisture
sensors, temperature sensors, accelerometers, gyroscopes,
compasses, magnetic sensors, touch sensors, and other sensors,
components that form displays, touch sensors arrays (e.g., arrays
of capacitive touch sensor electrodes to form a touch sensor that
detects touch events in two dimensions), and other input-output
devices. Circuitry 16 may also include control circuitry such as
non-volatile and volatile memory, microprocessors,
application-specific integrated circuits, system-on-chip devices,
baseband processors, wired and wireless communications circuitry,
and other integrated circuits.
[0027] Item 10 may interact with electronic equipment or other
additional items 18. Items 18 may be attached to item 10 or item 10
and item 18 may be separate items that are configured to operate
with each other (e.g., when one item is a case and the other is a
device that fits within the case, etc.). Circuitry 16 may include
antennas and other structures for supporting wireless
communications with item 18. Item 18 may also interact with
strand-based item 10 using a wired communications link or other
connection that allows information to be exchanged.
[0028] In some situations, item 18 may be an electronic device such
as a cellular telephone, computer, or other portable electronic
device and strand-based item 10 may form a case or other structure
that receives the electronic device in a pocket, an interior
cavity, or other portion of item 10. In other situations, item 18
may be a wrist-watch device or other electronic device and item 10
may be a strap or other strand-based item that is attached to item
18. In still other situations, item 10 may be an electronic device,
strands 12 may be used in forming the electronic device, and
additional items 18 may include accessories or other devices that
interact with item 10.
[0029] If desired, magnets and other structures in items 10 and/or
18 may allow items 10 and 18 to interact wirelessly. One item may,
for example, include a magnet that produces a magnetic field and
the other item may include a magnetic switch or magnetic sensor
that responds in the presence of the magnetic field. Items 10 and
18 may also interact with themselves or each other using
pressure-sensitive switches, pressure sensors, force sensors,
proximity sensors, light-based sensors, interlocking electrical
connectors, etc.
[0030] The strands that make up item 10 may be intertwined using
any suitable strand intertwining equipment. For example, strands 12
may be woven together to form a fabric. The fabric may have a plain
weave, a satin weave, a twill weave, or variations of these weaves,
may be a three-dimensional woven fabric, or may be other suitable
woven fabric. If desired, the strands that make up item 10 may be
intertwined using knitting equipment, braiding equipment, or other
strand intertwining equipment. Item 10 may also incorporate more
than one type of fabric or intertwined strand-based material (e.g.,
item 10 may include both woven and knitted portions).
[0031] The strands that make up item 10 may be intertwined to form
a fabric such as illustrative fabric 20 of FIG. 2. Fabric 20 may
include strands 12. Strands 12 may be formed from conductive and/or
insulating materials. As an example, fabric may be formed from
insulating strands 28 interspersed with conductive strands 22. In
the illustrative configuration of FIG. 2, a first conductive strand
22 extends vertically and electrically connects node A with
junction 24 and a second conductive strand 22 extends horizontally
(i.e., perpendicular to the first conductive strand) and
electrically connects node B with junction 24. At the intersection
of the first and second conductive strands at junction 24, the
first and second strands may be electrically connected using
mechanical contact, solder, welds, conductive adhesive, a crimped
metal connection or other metal connector, or other electrical
connection structure. Using this type of technique, desired signal
paths such as illustrative signal path 26 between nodes A and B may
be formed within fabric 20 (e.g., to form signal busses, to form
electrodes or other parts of sensors, to form other conductive
structures, etc.).
[0032] Conductive strands such as conductive strands 22 in
illustrative fabric 20 for item 10 may be formed from one or more
layered materials. For example, conductive strand 22 may have a
core (e.g., an elongated member such as a monofilament), a
conductive inner coating, and an outer insulating coating.
[0033] The different portions of the conductive strand may be
formed from different materials or, if desired, two or more of the
portions of the conductive strand may be formed from the same
material. As an example, a conductive strand may have a core and an
outer coating that are formed from a common dielectric and that are
separated by an intermediate layer formed from a conductive
material. Configurations may also be used in which a conductive
strand has a core formed from a first dielectric and an outer layer
formed from a second dielectric and in which the first and second
dielectrics are separated from each other by an intervening
conductive layer such as a metal layer.
[0034] In some configurations, conductive strand 22 may contain
polymer. For example, conductive strand 22 may contain a polymer
core to provide strand 22 with strength and flexibility. Polymer
may also be used in forming insulating outer coating layers.
Examples of polymers that may be used in forming a core and/or an
outer insulating coating for conductive strand 22 include polyamide
(nylon--e.g., nylon6, nylon6,6, nylon 11), aromatic polyamide
(i.e., para-aramids such as Kevlar.RTM. or other aramids),
polyimide, polyester, polyolefin, acrylic, aromatic polyesters such
as Vectran.RTM., polyethylene, extruded cellulosic polymers such as
rayon and Tencel.RTM., polyvinyl formal, polyester-polyimide,
polyamide-polyimide, polytetrafluoroethylene, and polyurethane.
Other polymers or mixtures of these polymers may be used, if
desired. Inorganic materials may also be used in forming dielectric
strand cores and insulating layers. Illustrative configurations in
which these strand structures are formed from polymers are
sometimes described herein as an example.
[0035] The polymer materials of strand 22 may be formed from
conductive organic material, from insulating polymeric materials
(e.g., materials to form a dielectric core and/or outer coating),
from polymer that includes conductive filler such as particles of
metal, particles of carbon nanotube material, graphene particles,
fibrous carbon material, or other conductive particles. Conductive
filler may be incorporated into the polymer in a concentration that
renders a portion of strand 22 conductive or may be incorporated
into the polymer in a lower concentration (e.g., to promote
adhesion or otherwise enhance compatibility with other portions of
strand 22 without necessarily increasing the conductivity of the
polymer to a level that allows the material to serve as a
conductive signal path in fabric 20).
[0036] In some situations, monofilaments may be formed of metal or
polymer (i.e., polymer with conductive filler or without conductive
filter). These monofilaments may be intertwined to form strands 22
or portions of strands 22. In general, strands 22 may have one or
more materials, two or more materials, three or more materials,
four or more materials, or five or more materials. The structures
of strands 22 may incorporate conductive materials such as metal,
insulating materials such as polymer, conductive organic materials
such as conductive polymer, polymer filled with metal particles and
other conductive filler, other materials, and/or combinations of
these materials.
[0037] FIG. 3 is a diagram showing different types of equipment 60
that may be used in processing strands 12 (e.g., non-conductive
strands 28 and conductive strands 22) and/or that may be used in
processing strand-based item 10. As shown in FIG. 3, equipment 60
may include strand core formation equipment 68. Equipment 68 may
include, for example, equipment for extruding and/or otherwise
forming polymer cores for strands 12. Conductive coating
application tool 62 may be used to apply one or more conductive
coatings. For example, tool 62 may be used to apply a metal coating
to a polymer strand core to form a conductive strand 22. Dielectric
coating application tool 66 may be used to apply a polymer layer or
other insulating coating. For example, tool 66 may be used to apply
a thin polymer coating to the exposed metal coating on a polymer
strand core, thereby forming an insulated conductive strand 22.
[0038] Equipment 64 may be used in processing strands 12. Equipment
64 may include a heat source (e.g., a flame, a heated metal
structure or other heated structure, a lamp that produces heat, an
oven, etc.). Equipment 64 may also include a laser, light-emitting
diode, or other light source (e.g., an infrared laser or infrared
light-emitting diode, a visible laser or visible light-emitting
diode, and/or an ultraviolet laser or light-emitting diode). By
applying heat or light or other energy to strands 12 or by using
equipment 64 to mechanically or chemically remove material from
strands 12, coatings can be selectively removed, liquid polymers
and other coating materials may be cured, the texture of strand 12
may be altered, or other strand modifications can be made.
[0039] Equipment 64 may be used in attaching electrical components
such as electrical components in circuitry 16 of FIG. 1 to strands
such as conductive strands 22. For example, equipment 64 may be
used to attach electrical components to strands 22 using solder
joints, crimped metal connections, welds, conductive adhesive, or
other conductive attachment structures. The electrical components
that are attached to strands in this way may include light-emitting
components, integrated circuits, light-emitting diodes,
light-emitting diodes that are packaged with transistor-based
circuitry such as communications circuitry and/or light-emitting
diode driver circuitry that allows each component to operate as a
pixel in a display, discrete components such as resistors,
capacitors, and inductors, audio components such as microphones
and/or speakers, sensors such as touch sensors (with or without
co-located touch sensor processing circuitry), accelerometers,
temperature sensors, force sensors, microelectromechanical systems
(MEMS) devices, transducers, solenoids, electromagnets, pressure
sensors, light-sensors, proximity sensors, buttons, switches,
two-terminal devices, three-terminal devices, devices with four or
more contacts, etc. Electrical connections for attaching electrical
components to strands 12 using equipment 64 may be formed using
solder, conductive adhesive, welds, molded package parts,
mechanical fasteners, wrapped strand connections, press-fit
connections, crimped connections (e.g., bend metal prong
connections), and other mechanical connections, portions of liquid
coatings (e.g., metallic paint, conductive adhesive, etc.) that are
selectively applied to strands 12 using equipment 100, or using any
other suitable arrangement for forming an electrical short between
conductive structures.
[0040] Strand intertwining equipment 70 (e.g., weaving equipment,
knitting equipment, braiding equipment, or other strand
intertwining equipment) may be used in intertwining strands 12 to
form fabric and other structures for strand-based item 10.
Equipment 60 may be used to process strands 12 before, during, or
after processing of strands 12 with equipment 70 to form item
10.
[0041] FIG. 4 is a diagram of illustrative equipment for forming a
polymer strand core that is coated with a metal coating. As shown
in FIG. 4, polymer strand core 80 may be produced by polymer strand
formation tool 68 (e.g., an extrusion tool, a polymer fiber
spinning tool, etc.). Tool 68 may dispense core 80 in direction 84.
Tool 68 may include polymer source 86. The polymer for core 80 may
be a thermoplastic that is melted to form a liquid polymer material
or may be a polymer material that is dissolved in a solvent to form
a liquid polymer material. Tool 68 may have a cavity and extrusion
head (shown as portion 88) to receive polymer from source 86 and to
hold the polymer in liquid form. Portion 88 of tool 68 may dispense
the liquid polymer in the form of strand core 80. Strand core 80
may be formed using extrusion or other suitable techniques. If
desired, spinning techniques may be used to produce spun strands.
Other techniques may also be used in forming core 80. An optional
pulley system or other equipment may be used to stretch core 80 to
decrease the diameter of core 80. The core formation equipment of
FIG. 4 is merely illustrative.
[0042] Following formation of polymer core 80, coating tool 62 may
be used to apply coating 90 to core 80. Tool 62 may, as an example,
apply a metal coating to core 80 using electrochemical deposition
(e.g., electroless plating or electroplating using an applied
current). Coating 90 may also be deposited by physical vapor
deposition, chemical vapor deposition, dipping and curing (e.g.,
when coating core 90 with a conductive liquid layer coating layer
such as a conductive polymer or a polymer with a conductive
filler), application from a brush, needle, liquid-infused pad, or
other dispenser, or other coating technique. After coating core 80
with conductive coating 90 to form coated strand 96, strand 96 may
be wound onto drum 92 or provided directly to downstream processing
equipment.
[0043] FIG. 5 is a diagram of illustrative equipment 66 for forming
a polymer coating or other dielectric coating on the exterior of
strand 96 (i.e., on coating 90 on strand core 80). As shown in FIG.
5, drum 92' (which may be the same drum as drum 92 of FIG. 4 or
another strand dispensing structure) may provide strand 96 (i.e.,
core 80 that has been coated with coating 90 using equipment of the
type shown in FIG. 4) to coating equipment 100. Coating equipment
100 may include a source of liquid polymer precursor material such
as liquid polymer reservoir 102. Liquid-impregnated pad 104 may be
formed from a porous material such as open-cell foam, felt, or
other material and may be used to apply liquid polymer coating 110
to the exterior of strand 96. If desired, liquid polymer materials
may be dispensed by passing strand 96 through a pool of liquid
polymer, by spraying, dripping, dipping, or other dispensing
techniques. Curing equipment 112 may apply materials (e.g.,
catalyst) and/or energy (e.g., light such as ultraviolet light or
heat) to coating 110, as indicated schematically by lines 114.
Curing equipment 112 may, for example, be an oven or heat lamp for
thermally curing liquid polymer precursor material to form an
insulating polymer coating. Curing equipment 112 may also be based
on a visible or ultraviolet light source, equipment for spraying or
otherwise dispensing liquid catalyst, etc.
[0044] The curing of coating 110 to form a polymer insulating
coating on the exterior surface of strand metal layer 90 forms
conductive strand 22. Drum 120 or other equipment may be used to
receive completed conductive strands such as strand 22. Strand 22
may then be provided with other strands (e.g., non-conductive
strands 28) to strand intertwining equipment 70 to use in
constructing item 10.
[0045] FIG. 6 is a cross-sectional side view of an illustrative
strand core. Core 80 of FIG. 6 has a circular cross-sectional
shape, but core 80 may have other shapes if desired. Core 80 may be
formed from para-aramid fiber (e.g., Kevlar.RTM.), spun aromatic
polyester fiber (e.g., Vectran.RTM.), or other polymer fiber. Core
80 is preferably thermally stable (e.g., core 80 is preferably able
to withstand exposure to elevated temperatures without incurring
damage). The elevated temperatures may be, for example,
temperatures of 200-300.degree. C., more than 150.degree. C., more
than 250.degree. C., more than 350.degree. C., less than
250.degree. C., 210-220.degree. C., or other suitable temperatures.
Core 80 also preferably has a high elastic modulus (Young's
modulus), such as a modulus of 50-250 GPa, 50-150 GPa, 100-200 GPa,
more than 50 GPa, less than 250 GPa, etc. If desired, core 80 may
have other advantageous physical attributes such as being
insensitive to degradation due to exposure to light, having a good
abrasion resistance, being highly flexible, exhibiting a high
strength-to-weight ratio, forming a good electrical insulator,
etc.
[0046] To form fabrics and other intertwined strands with desired
properties, it may be desirable for the diameter of core 80 to be
relatively small. As an example, diameter D of core 80 may be 50-70
microns, 25-100 microns, less than 100 microns, less than 150
microns, more than 10 microns, 10-200 microns, 10-500 microns,
150-250 microns, more than 50 microns, less than 400 microns, or
other suitable diameter. The linear mass density of core 80 may be
220 denier, 130 denier, 55 denier, 28 denier, less than 100 denier,
less than 75 denier, 75-20 denier, 75-25 denier, less than 60
denier, 60-25 denier, more than 10 denier, more than 20 denier, or
other suitable linear mass density.
[0047] FIG. 7 is a cross-sectional side view of strand 96 (i.e.,
core 80 after coating with conductive coating layer 90). The
thickness T1 of coating 90 may be 25 microns, more than 1 micron,
more than 5 microns, less than 25 microns, less than 10 microns,
less than 100 microns, 10-50 microns, 20-70 microns, more than 15
microns, more than 20 microns, less than 35 microns, less than 50
microns, less than 5 microns, or other suitable thickness. Coating
90 may be a metal (e.g., an elemental metal such as silver and/or a
metal alloy) that has been deposited by electrochemical deposition,
physical vapor deposition, etc. or may be any other suitable
conductive layer.
[0048] FIG. 8 is a cross-sectional side view of conductive fiber
22. As shown in FIG. 8, conductive fiber 22 may have core 80,
conductive coating 90, and insulating coating 110. Coating 110 may
have a thickness T2 of 1-2 microns, more than 0.5 microns, less
than 3 microns, less than 4 microns, 0.4-5 microns, less than 5
microns, less than 10 microns, less than 15 microns, less than 20
microns, 0.2-10 microns, more than 0.7 microns, or other suitable
thickness. Coating 110 may include one or more dielectric sublayers
(e.g., one layer, two layers, three layers, four layers, or more
than four layers). To ensure that strand 22 can withstand elevated
temperatures, coating 110 is preferably able to withstand elevated
temperatures (e.g., temperatures of 200-300.degree. C., more than
150.degree. C., more than 250.degree. C., more than 350.degree. C.,
less than 250.degree. C., 210-220.degree. C., or other suitable
temperatures). Examples of insulating coating materials that may be
used for coating 110 include polyvinyl formal, polyester-polyimide,
polyamide-polyimide, polyamide, polyimide, polyester,
polytetrafluoroethylene, and polyurethane. Other polymers or
mixtures of these polymers may be used, if desired. In
configurations in which coating layer 110 is formed from multiple
sublayers, each sublayer may be formed from the same material or
some or all of the sublayers may be formed from different
materials.
[0049] Illustrative steps involved in forming strands and items
such as strands 12 and item 10 are shown in FIG. 9.
[0050] At step 200, a strand core for conductive strands such as
strand 22 may be formed using equipment 68 (e.g., by extrusion of
liquid polymer, by spinning of liquid polymer, etc.). The size of
the strand core may, if desired, be relatively small (e.g., having
a linear mass density of less than 100 denier) or may be any other
suitable size.
[0051] At step 202, a metal coating or other conductive coating 90
may be formed using equipment 62 (e.g., electrochemical deposition
equipment, physical vapor deposition equipment, etc.). The
thickness of the metal coating may be relatively thin (e.g., less
than 20 microns or other suitable thickness).
[0052] At step 204, dielectric coating equipment 66 may be used to
form dielectric outer coating 110 on layer 90, thereby forming
conductive strand 22. If desired, multiple strands may be braided
together (e.g., 5-10 strands, more than 3 strands, fewer than 12
strands, etc.) to form a thread or other strand that contains
multiple smaller strands. These smaller strands may be insulating
and/or conductive strands. Insulating coating 110 may be formed by
applying a liquid polymer coating to a relatively thin thickness
and curing the applied coating using heat or light to produce cured
coating 110 (e.g., a coating having a thickness of less than 5
microns or other suitable thickness).
[0053] At step 206, intertwining equipment 70 may be used to
intertwine strands 12 and other equipment may be used in assembling
strand-based materials into desired strand-based items such as item
10. To ensure that the physical properties of fabric and other
items formed from intertwined strands 12 are satisfactory, it may
be desirable to form conductive strands 22 with a size (e.g.,
diameter and/or denier) that is close (e.g., within 50%, within
25%, or within 10%) of the size (e.g., diameter and/or denier) of
non-conducting strands 28. When these strands are woven, knitted,
or otherwise combined to form fabric or other intertwined strand
materials, the closeness of the size and other properties of
strands 22 and 28 may help avoid undesired discontinuities in the
appearance and feel of the fabric or other materials. Ensuring that
the conductive and non-conductive strands in item 10 are similar in
size may also help form electrical connections between overlapping
strands (e.g., junctions such as junction 24 of FIG. 2 may be
formed reliably).
[0054] In accordance with an embodiment. intertwined strands of
material are provided that include non-conductive strands, and
conductive strands that are intertwined with the non-conductive
strands, each conductive strand has a strand core, a conductive
coating on the strand core, and an insulating coating on the
conductive core.
[0055] In accordance with another embodiment, the strand core of
each conductive strand includes a dielectric material.
[0056] In accordance with another embodiment, the strand core of
each conductive strand includes a polymer.
[0057] In accordance with another embodiment, the polymer is
selected from the group consisting of polyamide, aromatic
polyamide, polyimide, polyester, polyolefin, acrylic, aromatic
polyesters, polyethylene, cellulosic polymer, and polyurethane.
[0058] In accordance with another embodiment, the polymer is a
para-aramid.
[0059] In accordance with another embodiment, the polymer is an
aromatic polyester.
[0060] In accordance with another embodiment, the conductive
coating includes metal and the strand core has a linear mass
density of less than 100 denier.
[0061] In accordance with another embodiment, the conductive
coating includes silver.
[0062] In accordance with another embodiment, the insulating
coating includes a polymer coating having a thickness of less than
5 microns.
[0063] In accordance with another embodiment, the insulating
coating includes a polymer material selected from the group
consisting of polyvinyl formal, polyester-polyimide,
polyamide-polyimide, polyamide, polyimide, polyester,
polytetrafluoroethylene, and polyurethane.
[0064] In accordance with another embodiment, the conductive
coating is a metal coating.
[0065] In accordance with another embodiment, the strand core
includes a material selected from the group consisting of
para-aramid and polyester.
[0066] In accordance with another embodiment, the insulating
coating has a thickness of less than 5 microns.
[0067] In accordance with another embodiment, the metal coating
includes silver.
[0068] In accordance with another embodiment, the non-conductive
strands have a first diameter, the conductive strands have a second
diameter, and the second diameter is within 30% of the first
diameter.
[0069] In accordance with another embodiment, the non-conductive
strands have a first diameter, the conductive strands have a second
diameter, and the second diameter is within 50% of the first
diameter.
[0070] In accordance with another embodiment, the strand core of
each conductive strand is a polymer strand, the conductive coating
of each conductive strand is a metal coating, and the insulating
coating of each conductive strand has a thickness of less than 3
microns.
[0071] In accordance with an embodiment, a fabric-based item is
provided that includes circuitry, and intertwined strands of
material including conductive strands that carry signals for the
circuitry and non-conductive strands, the conductive strands each
have a polymer strand core, a metal coating on the polymer strand
core, and an insulating coating on the metal coating.
[0072] In accordance with another embodiment, the insulating
coating has a thickness of less than 5 microns.
[0073] In accordance with another embodiment, the insulating
coating includes a material selected from the group consisting of
polyvinyl formal, polyester-polyimide, polyamide-polyimide,
polyamide, polyimide, polyester, polytetrafluoroethylene, and
polyurethane.
[0074] In accordance with another embodiment, the conductive
coating includes metal and the strand core has a linear mass
density of less than 100 denier.
[0075] In accordance with an embodiment, a fabric-based item is
provided that includes electrical components that produce signals,
and fabric that includes non-conductive strands and conductive
strands, the conductive strands carry the signals and each
conductive strand has a polymer strand core with a linear mass
density of less than 100 denier, a metal coating on the polymer
strand core, and an insulating coating with a thickness of less
than 5 microns on the metal coating.
[0076] The foregoing is merely illustrative and various
modifications can be made by those skilled in the art without
departing from the scope and spirit of the described embodiments.
The foregoing embodiments may be implemented individually or in any
combination.
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