U.S. patent application number 11/010559 was filed with the patent office on 2005-09-15 for method and device for coating a substrate.
This patent application is currently assigned to Wavezero, Inc.. Invention is credited to Arnold, Rocky R..
Application Number | 20050202174 11/010559 |
Document ID | / |
Family ID | 26886569 |
Filed Date | 2005-09-15 |
United States Patent
Application |
20050202174 |
Kind Code |
A1 |
Arnold, Rocky R. |
September 15, 2005 |
Method and device for coating a substrate
Abstract
Apparatus and methods for coating a substrate. In an exemplary
embodiment, the apparatus are used to create a metallized substrate
for use as an EMI/RFI shield. The apparatus typically includes a
movable processing apparatus that is movable orthogonal to the
substrate to treat the substrate. The processing apparatus can
include a surface preparation assembly, a heating assembly, a
thermoforming assembly, a metallizing assembly, a cutting assembly,
or the like.
Inventors: |
Arnold, Rocky R.; (San
Carlos, CA) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER
EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
Wavezero, Inc.
Sunnyvale
CA
Shielding for Electronics, Inc.
Sunnyvale
CA
|
Family ID: |
26886569 |
Appl. No.: |
11/010559 |
Filed: |
December 13, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11010559 |
Dec 13, 2004 |
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09812075 |
Mar 19, 2001 |
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6833031 |
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60198777 |
Apr 21, 2000 |
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60190920 |
Mar 21, 2000 |
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Current U.S.
Class: |
427/250 ; 118/44;
118/50; 118/718; 427/289 |
Current CPC
Class: |
C23C 14/56 20130101 |
Class at
Publication: |
427/250 ;
427/289; 118/718; 118/044; 118/050 |
International
Class: |
C23C 014/00; C23C
016/00; B05C 011/00 |
Claims
1.-31. (canceled)
32. A method of manufacturing a EMI shield, the method comprising:
positioning a substrate on a support; moving a processing apparatus
adjacent to the substrate; depositing a metal layer on the
substrate; and moving the processing apparatus away from the
substrate.
33. The method of claim 32 further comprising creating a vacuum
around at least a portion of the substrate.
34. The method of claim 32 further comprising moving the substrate
along the support.
35. The method of claim 32 further comprising shaping the substrate
before depositing the metal layer.
36. The method of claim 35 wherein depositing requires rotating a
processing apparatus to rotate a shaping module away from the
substrate and a metal depositing module toward the substrate.
37. The method of claim 35 comprising cutting the shaped substrate
after depositing the metal layer.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] The present application claims benefit, under 37 C.F.R.
.sctn. 1.78, of provisional patent application Ser. No. 60/190,920,
filed Mar. 21, 2000 and provisional patent application Ser. No.
60/198,777, filed Apr. 21, 2000, the complete disclosures of which
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to methods and
systems for coating a substrate. More particularly, the present
invention relates to methods and devices for depositing a metal
layer onto a thermoform that is of a sufficient thickness for
shielding of electromagnetic interference ("EMI") and
radiofrequency interference ("RFI").
[0003] U.S. Pat. No. 5,811,050 to Gabower, which is incorporated
herein by reference, has proposed depositing a thin layer of metal
onto a thermoform to create a protective barrier for EMI and RFI.
One method for depositing the metal layer onto the thermoform is a
batch mode process. A first step of the method includes
thermoforming (i.e. shaping) the thermoform substrate. The shaped
thermoforms are then placed into the vacuum chamber and a vacuum
source is used to create a vacuum in the chamber. A source of metal
is vaporized and deposited onto the thermoform substrate.
[0004] Unfortunately, the batch processes is slow, time consuming,
and impurities can be introduced into the metallized object during
transport into and out of the vacuum chamber. For example, one
specific problem with the batch process is the creation of the
vacuum environment in the deposition chamber. Because the vacuum
chamber usually has a large volume (typically about 300,000
in.sup.3), the creation of the vacuum environment takes a long
period of time to create. Another problem of batch processing is
that the thermoform must be separately shaped and cut from the
thermoform sheet and it is often necessary to manually handle the
thermoformed substrate, both prior and subsequent to the coating
process. Care must be taken in such handling steps to avoid
contamination or introduction of impurities which may lead to
imperfections in the metal layer and leakage in the EMI/RFI
shield.
[0005] Therefore, what is needed are vapor deposition processes and
apparatuses for coating objects with a coating material that have
improved process speed and improved process control
characteristics.
DESCRIPTION OF BACKGROUND ART
[0006] U.S. Pat. No. 5,908,506 provides a continuous vapor
deposition apparatus that appears to have stationary process
chambers. U.S. Pat. No. 5,811,050 describes an apparatus for vacuum
depositing a metallic coating on thermoformed blanks that are
placed on a carrier that revolves around a stationary tungsten
filament. U.S. Pat. No. 5,076,203 recites passing a web over spools
past a stationary source of metal and an electron beam heater. U.S.
Pat. No. 4,261,808 describes a vertical vacuum coating apparatus
that deposits a metal layer onto a moving substrate with a fixed
cathode system.
SUMMARY OF THE INVENTION
[0007] The present invention provides improved methods and systems
for depositing a coating material onto a substrate. In exemplary
embodiments, the methods and systems are used for vacuum
metallizing a thermoform or other substrate for creating an EMI RFI
shield.
[0008] The systems of the present invention generally have at least
one processing apparatus that is movable orthogonal to a plane of
the substrate. The processing apparatus can be moved adjacent the
substrate or to contact the substrate, a platform, and/or a second
processing apparatus to process the substrate. In some embodiments,
the processing apparatuses have a small volume cavity in which a
vacuum can be created for the delivery of a vaporized metal or
other coating material. The small vacuum cavities of the processing
apparatuses of the present invention allow a vacuum source to
create a vacuum environment in a shorter amount of time than
conventional vacuum chambers, thus improving the speed of
manufacturing of the substrates. The cavities of the processing
apparatuses can house a shaping assembly, a pre-treatment assembly
(e.g. glow discharge), a metallizing assembly (e.g. vacuum
metallization, arc plasma deposition, ion deposition), heating
elements, a cutting assembly or the like.
[0009] In some configurations, the systems of the present invention
are configured as in-line system that has a plurality of movable
processing apparatuses. Advantageously, the in-line systems of the
present invention allow for the processing of spools or rolls of a
substrate, such as a thermoform, such that no manual handling of
the thermoform is required in intermediate steps. The processing
apparatuses can be configured to thermoform, pre-treat the
substrate, metallize and/or cut the thermoform using the single
in-line system.
[0010] The substrate may enter into the processing area either as a
structural form which has been subject to prior processing
(referred to as thermoforming) or the substrate may enter the
processing area as a flat substrate and be subject to thermoforming
followed by metallization, or alternatively vacuum metallization
followed by thermoforming. For example, in some exemplary
embodiments, the systems of the present invention include a series
of movable processing apparatuses on one or both sides of the
substrate. The assemblies can all be adapted to perform the same
function (e.g. metallize) or each of the processing apparatuses can
perform different functions (e.g., thermoform, metallize and cut).
For example, for one exemplary in-line system, the substrate can be
moved to a first processing apparatus for shaping (e.g.,
thermoforming) of the substrate. The shaped substrate can be then
be moved to a second processing apparatus which can deposit a metal
layer onto the shaped substrate (e.g., vacuum metallization).
Finally, the shaped and metallized substrate can be transported to
a third processing apparatus that can cut the shaped and metallized
form out of the substrate. It should be appreciated that additional
processing apparatuses can also be incorporated into the previous
example, such as surface treatment apparatuses, heating
apparatuses, or the like.
[0011] In some exemplary configurations, the processing apparatuses
of the present invention can include one or more modular units for
providing multiple interfaces for processing the substrate. Such
processing apparatuses will be movable orthogonal to the plane of
the substrate and rotatable so that a desired processing interface
of the modular units can be moved into position to process the
substrate. Such a configuration allows for a multitude of processes
to be accomplished either on a single sheet of material or as a
part of a continuous inline process in which a polymer or flexible
film is unrolled and processed from beginning to end.
[0012] Typically, each processing apparatus includes at least three
modular units, and preferably between three and six modular units.
Each modular unit of each processing apparatus can have the same or
different functions. For example, in some processing apparatuses
each of the modular units will have the same modular unit, for
example a metallization unit. The metallization unit will be used
deposit a metal layer onto the substrate. Once the metal source has
been depleted in the metallization unit, the processing apparatus
can be rotated and a metallization unit having a full metal source
can be used. Once the depleted metal source has been rotated away,
the metal source can be manually or mechanically replaced. Such a
configuration limits the "down time" of the system and improves the
output and production of the system.
[0013] Alternatively, each of the modular units of the processing
apparatus can have a different functional modular unit. For
example, a first modular unit can be used to heat the thermoform.
The first modular unit can be rotated away and a second shaping
modular unit can process and shape the substrate. Thereafter, the
next modular units, such as a surface treatment assembly,
metallization assembly, and cutting assembly modular unit can be
rotated towards the substrate to process the substrate.
Advantageously, if desired the rotatable, modular processing
apparatuses allow for multiple or complete processing of the
substrate while maintaining the position of a substrate in a single
position. Such systems can reduce the footprint of the system on
the manufacturing floor.
[0014] In exemplary embodiments, the present invention can create
EMI/RFI shields that can be used within electronic devices and
products to reduce the amount of electromagnetic radiation that is
emitted from and enters the electronic device. In an exemplary
embodiment, the EMI/RFI shields enabled by the equipment described
above are based upon the application of a relatively stable and
uniform layer of aluminum on a polymer substrate. The present
invention can apply any number of different metal layers (e.g.,
silver, copper, gold, nickel, or the like) to any number of
substrate materials (e.g., polycarbonate, ABS, PVC, or the like)
through a variety of metallization processes.
[0015] In one aspect, the present invention provides an apparatus
for coating a substrate. The apparatus comprises a support that
supports the substrate and at least one movable processing
apparatus that can deposit a metal layer onto the substrate. The
processing apparatus is movable between a first position adjacent
the substrate and a second position apart from the substrate.
[0016] In another aspect, the present invention provides an
apparatus for metallizing a substrate. The apparatus comprises a
support that can maintain at least a portion of the substrate along
a first plane and at least one rotatable processing apparatus that
is movable substantially orthogonal to the orientation of the
substrate. The processing apparatus comprises a plurality of
modular units that includes at least one of a thermoform assembly,
a heating assembly, a metallizing assembly, or a cutting
assembly.
[0017] In another aspect, the present invention provides an in-line
apparatus for creating an EMI shield, the apparatus comprises a
conveyor assembly that moves a substrate from a first position to a
second position and a movable shaping chamber disposed at the first
position to shape the substrate. A metallization chamber can create
a seal around the shaped substrate and can deposit a metal layer
onto the shaped substrate, and a cutting assembly disposed at the
second position to cut the shaped substrate, the cutting assembly
being movable relative to the shaped substrate.
[0018] In yet another aspect, the present invention provides a
method of manufacturing an EMI shield. The method comprises
positioning a substrate on a support. A processing apparatus is
moved adjacent to the substrate, a metal layer is deposited on the
substrate and the processing apparatus is moved away from the
substrate.
[0019] For a further understanding of the nature and advantages of
the invention, reference should be made to the following
description taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a simplified cross sectional view of a processing
apparatus of the present invention;
[0021] FIG. 2 is a cross sectional view of a simplified exemplary
processing apparatus of the present invention;
[0022] FIG. 3 is a simplified view of a system comprising a
plurality of processing apparatuses in which the processing
apparatuses are disposed on both sides of a substrate;
[0023] FIG. 4 is a partial cross sectional view of a first and
second processing apparatus;
[0024] FIG. 5 is a simplified top view of a system of the present
invention;
[0025] FIG. 6 is an end view of an upper and lower processing
apparatus;
[0026] FIGS. 7A and 7B are end views of a single removable, modular
unit of the processing apparatus;
[0027] FIG. 8A is a top view illustrating the cavity of the modular
unit of FIGS. 7A and 7B;
[0028] FIG. 8B is a cross sectional view along line A-A of FIG.
8A;
[0029] FIG. 9 is an end view of two attached modular units of the
processing apparatus;
[0030] FIG. 10A is a top view of a modular unit comprising heating
elements;
[0031] FIG. 10B is a cross-sectional end view of a modular unit
comprising heating elements;
[0032] FIG. 11A is a top view of a modular unit comprising a
conditioning assembly;
[0033] FIG. 11B is a cross sectional end view of a modular unit
comprising a conditioning assembly;
[0034] FIG. 12A is a top view of a modular assembly comprising a
plurality of filaments and canes;
[0035] FIG. 12B is a cross-sectional end view of a modular unit
comprising a plurality of filaments and canes;
[0036] FIG. 13 is a close-up view of a metal cane and a
filament;
[0037] FIG. 14 is a close-up view of another embodiment of a metal
cane and a filament;
[0038] FIG. 15 is a top view of a shaped substrate within the
processing zone of the modular unit;
[0039] FIG. 16 is a cross-sectional end view illustrating a modular
unit comprising a steel-rule die; and
[0040] FIG. 17 is a schematic view of a processing system of the
present invention.
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
[0041] The present invention provides improved systems and methods
for depositing a metal layer onto a shaped polymer substrate. In
exemplary embodiment, the systems of the present invention rely on
the use of at least one movable processing apparatus to treat a
substrate. Treatments can include surface treatment, preheating,
shaping, depositing a metal layer, cutting, or the like.
[0042] In a specific use, the methods and systems of the present
invention are for use in producing EMI/RFI shields for electronic
devices. In particular, the final EMI/RFI shields are composed of a
metallized thermoform that are manufactured with the processes and
systems of the present invention. In most embodiments, the systems
of the present invention include at least one movable processing
apparatus, and typically a first processing apparatus disposed on a
first side of the substrate and a second processing apparatus
disposed on a second side of the substrate. Such a configuration
helps in the efficient treatment of both sides of the substrate.
For example, in the embodiments in which the processing apparatus
shapes the substrate, the first processing apparatus can include a
mold while the second side can include a corresponding mold to
shape the substrate. Moreover, if the processing apparatus is used
to deposit a metal layer onto the substrate, both the first and
second processing apparatus can be used so as to metallize both
sides of the substrate.
[0043] While the remaining discussion will focus on an in-line
process for thermoforming, metallizing, and cutting a polymer
substrate to create an EMI/RFI shield, it should be appreciated
that the apparatuses of the present invention can be adapted to
perform only a single process of the processing of the substrate.
For example, the apparatuses of the present invention can be used
to only metallize flat substrates. Alternatively, the apparatuses
of the present invention can be used to only shape (e.g.,
thermoform) the substrate. Additionally, the apparatus does not
have to be an in-line process, but instead the processing apparatus
can be a stand alone device that allows a user to manually position
the substrate in a processing position. Finally, it should also be
appreciated that the methods and systems of the present invention
can also extend to depositing a coating on any type of
substrate.
[0044] Referring now to FIG. 1, one exemplary system 10 of the
present invention includes a housing 11 having a support 12 that
can position a substrate 14 adjacent at least one processing
apparatus 16. The processing apparatus is movable relative to the
substrate 14 and will typically be movable orthogonal from the
substrate 14 when the substrate is positioned on the support 12
(i.e. up/down in the case of a vertical application or forward/back
in the case of a horizontal application.).
[0045] As illustrated in FIG. 2, each of the processing apparatus
16 typically includes a body 18 that defines a cavity 20. The body
typically has at least one conduit 22 for delivering a gas,
creating a vacuum, delivering electrical energy to the cavity, or
the like. As the processing apparatus 16 moves adjacent the
substrate 14, some processing apparatuses can contact the support
12, the substrate 14 and/or a platform 24 (FIG. 1) to provide a
seal around the target portion of the substrate 14. Thereafter, if
desired, a vacuum can be created around the target portion of the
substrate 14 prior to a delivery of a metal onto the substrate. The
cavity 20 typically will have a volume between approximately 16,000
in.sup.3 and ______ in.sup.3. In contrast, standard vacuum chambers
will have a total volume of almost 300,000 in.sup.3. Because the
cavity has a smaller volume than conventional vacuum chambers, a
vacuum can be created quicker and the processing of the substrate
can be completed faster. It should be appreciated however, that the
size of the body 18 and cavity 20 can be varied to allow for
different sized substrates and different processing speeds.
Additionally, not all processes of the present invention require a
creation of a vacuum. For example, if the processing apparatus 16
is used to shape the substrate the body 18, the processing
apparatus may not have a cavity and a vacuum may not be created
around the substrate.
[0046] FIG. 3 illustrates another embodiment of the system of the
present invention. The system 10 can includes a plurality of
stations for treating the substrate 14. In the illustrated
embodiment, the system 10 can include a shaping station 26, a
metallization station 28, and a cutting station 30. Optionally, a
conveyor support 32 can be incorporated into the system to
transport the substrate 14 from station to station. It should be
appreciated however, that any number of stations can be provided,
and the stations can be positioned in any order desired. For
example, instead of having each station perform a different
function, each of the stations can be configured to deposit a metal
layer onto the substrate 14. Because each of the vacuum cavities
has a smaller volume than conventional vacuum chambers, a vacuum
can be created around the substrate quicker than conventional
vacuum chambers and the entire substrate can be metallized in a
shorter period of time.
[0047] As shown in FIG. 4, exemplary stations include a first unit
16 positioned on a first side 32 of the substrate and a second unit
16' positioned on a second side 34 of the substrate. The units 16,
16' will work in tandem to process the substrate so that when the
units are moved adjacent the substrate, each of the units can
simultaneously process both sides of the substrate. For example,
while not shown, the first unit 16 and second unit 16' can have
complimentary sides of a mold for shaping the substrate. The first
and second units will press the substrate to shape the substrate.
The first and second units can employ a heating element, a vacuum
and/or air pressure to facilitate forming of the substrate (not
shown). The next station can be used to deposit the metal layer
onto the shaped substrate 14. The first and second units can
contact the body 18, the substrate 14, and/or each other with
contact points 35 to create a vacuum around the shaped substrate.
The contact points can include aligned protrusions and detents to
create additional pressure on the substrate to prevent the leakage
of air into the chamber. Thereafter, a vacuum source (not shown)
can create a vacuum in the cavity 20 and the metal layer can be
deposited on one or two sides of the shaped substrate. Next, the
shaped and metallized substrate can be transported to the third
station where the shaped substrate will be at least partially cut
away from the remaining portion of the substrate with the first and
second units. The first and second units can include a cutting
assembly (not shown) that contacts the substrate to cut the shaped
portion of the substrate off of the remainder of the substrate.
[0048] FIG. 5 illustrates one representative system 10 of the
present invention. The substrate 14 is shown as a film roll moving
from left to right and between the first and second units 16. The
first and second units are connectable to a movable end unit 36
that provides an interface with fixed equipment. The end unit 36
can be connected to a source of electrical power 40, a gas unit 42
which houses various types of gases used in processing of the
substrate, a vacuum unit 44 which contains various types of pumps,
blowers, valves, or the like, necessary to effect and release
vacuum and sources 46 of other types of processing materials like
liquids or gases used to create positive pressure for some
thermoforming operations. The connections between the various units
are accomplished with suitably designed and conventional mechanical
quick connect/disconnect fittings and movable hoses and cables. The
systems of the present invention generally include a computer
control system (not shown) to control the movement of the
processing apparatuses, the end unit, the substrates, and the
like.
[0049] Exemplary rotatable processing apparatuses of the present
invention are illustrated in FIG. 6 to FIG. 19. The processing
apparatuses 16 can include a plurality of modular units 50 such
that rotation of the processing apparatuses 16 allows a different
modular unit to be moved adjacent or into contact with the
substrate. Such an assembly allows the processing apparatus to
perform a different process (or the same process) to the substrate
14 using only a single processing apparatus.
[0050] As illustrated in FIG. 6, the substrate 14 can be positioned
between the first and second apparatuses 16, 16' in a direction
substantially parallel to both a first unit centerline 52 and
second unit centerline 54. The substrate 14 is typically composed
of a nominally planar layer of material such as a metal, polymer,
ceramic, or the like. The first and second unit 16, 16' can rotate
clockwise or counterclockwise independently of one another and can
also move in a direction that is orthogonal to the substrate plane.
Movement of the first and second processing units towards the
substrate by the first and second units 16, 16' leads to contact
with the substrate and the creation of an isolated area on the
substrate where various processes can be performed on the
substrate.
[0051] Each of the first and second processing apparatuses 16, 16'
can include a plurality of nominally independent modular units 50.
FIGS. 7A and 7B show one specific embodiment of the present
invention in which each modular unit 50 is a detachable unit having
a triangular cross section. Each modular unit 50 can be coupled to
the remaining assembled modular units so as to form a complete
processing unit 16. The most extreme surface from a center of
rotation 58 is a processing plane 60. The processing plan can
contain an opening to the interior cavity 20 of the single modular
unit for purposes of performing various types of mechanical,
electrical, and thermal processing, as will be explained in more
detail below. In some configurations, the triangular modular units
50 can be coupled to a frame (not shown) of the processing unit
16.
[0052] FIGS. 8A and 8B show one embodiment of an individual modular
unit that contains a processing cavity 20. The body 18 surrounding
the cavity is of size, strength, and thickness as required to
perform a particular process. The surface 60 of the modular unit
typically comes in contact with the substrate 14. The surface is
typically used to form a seal with substrate 14. The seal may only
establish nominal contact so as to hold the substrate mechanically
or the seal may be have a tighter contact, for example with a
detent and protrusion (not shown) so as to enable the creation of a
vacuum between the substrate 14 and the cavity 20. In some
embodiments, the surface 60 can contact the support 12, a platform
24 or another surface of a second processing apparatus.
[0053] FIG. 9 shows a side view of two single modular units 50, 50'
that are attached via simple mechanical means, in this case, a cap
head bolt 62 positioned and size in such a manner so as to not
impose itself on an adjacent single modular units. The sides of the
modular units 50 may also contain grooves or other mechanical means
to achieve a tight and structural attachment of adjacent modular
units to form a process assembly 16.
[0054] As illustrated in FIGS. 10A to 13B, the modular units 50 of
the present invention can include a variety of treatment
assemblies. For example, as shown in FIGS. 10A and 10B the modular
unit can include a thermal assembly 64. The thermal assembly is
used to create and deliver heat via convection to one or both sides
of the substrate. The thermal assembly 64 can deliver heat through
cavity or chamber 20 with one or more heating elements 66 (such as
a resistive metal filament) that are connected to an electrical
circuit and energy source via a conduit 68. While resistive
filaments are illustrated, it should be appreciated that various
other conventional or proprietary heating assemblies can be used in
the modular units of the present invention. For example, in some
processes, by creating a vacuum, heat may be applied purely through
radiation.
[0055] FIGS. 11A and 11B illustrate a pre-conditioning assembly 70
that can be used with the modular unit 50 to create a more
favorable environment for a subsequent treatments of the substrate.
For clarity, a glow discharge process is depicted in which a gas
dispersal mechanism 72 is placed within the cavity 20 and a source
of gas (nitrogen, argon, etc.) is provided via an access hole and
conduit 74 that is connected to the source of gas (not shown). It
should be appreciated however, that this is but one example of a
pre-conditioning assembly that precedes a vacuum metallization
process and other pre-conditioning processes can be incorporated
into the modular units 50. Some examples include heating, gas
treatment, pre-forming to create a shape that has a desirable
pre-stress condition, and the like.
[0056] FIGS. 12A and 12B illustrates a metallization assembly 76
used for depositing a metal layer onto the substrate. It should be
appreciated that the preconditioning assembly 70 of FIG. 11A and
11B would be contained in the view of FIGS. 12A and 12B, but are
omitted for clarity. In a vacuum metallization process, tungsten
filaments 78 in various shapes but often of the form of a
spring-like spiral with an interior opening sufficient for the
placement of L-shaped "canes" 80 are placed around and within the
cavity. The tungsten filaments are connected to a source of
electrical energy via a conduit 82. A vacuum is created within the
cavity using a number of ports 81 that are connected to vacuum
source (not shown) having an external array of pumps, blowers, and
various other mechanical means for creating a vacuum. The filaments
78 and canes 80 can either be manually placed into the cavity or
automated equipment can be used to place the filaments 78 and canes
80 in the metallization assembly 76.
[0057] Two specific arrangements of the canes 80 and filaments 78
are illustrated in FIGS. 13 and 14. In the case of a vacuum
metallization process, the assembly of a metal canes 80 and a
tungsten filament 78 are placed into the electrical and mechanical
interface 82 much like pushing or screwing a light bulb into its
socket (FIG. 13). The electrical and mechanical interface 82
includes a conductive interior designed with sufficient mechanical
tolerances to allow the tungsten filament 78 to snugly fit and
remain in place while at the same time establishing an electrical
connection to the power source. The assembly of tungsten filament
and metal cane can be placed by hand from time to time as required
or it may be placed by any number of automated methods.
Alternatively, a long "bar" (not shown) may be pre-assembled in
which at regular distances the filament/cane combination is
attached to an electrically conductive bar which is, in turn, is
mechanical/electrically attached to certain points of the modular
unit 50 so as to establish a path for electricity to charge the
bar.
[0058] As shown in FIG. 14, combination of filament 78 and cane 80
can take any number of geometric configurations in order to
properly vaporize and distribute the metal cane. For example, in on
alternative configuration, the tungsten filament 78 may be a hollow
cylinder 84 that is connected to the mechanical/electrical
interface 82 by simply pushing it into a slightly larger
cylindrical opening in the modular unit. The cane can be in the
shape of a cylinder 86 that is simply pushed into the cylindrical
tungsten insert 84. The tungsten insert 84 or any other tungsten
filament configuration may be replaced with any suitable material
that provides for the rapid generation of heat (via resistance)
while retaining mechanical properties necessary for vacuum
metallization.
[0059] FIG. 15 is a top view of a process surface 60 and a shaped
substrate 14 located within a process zone and containing an area
intended to be cut out (AKA the "part" 88). For a polymer
substrate, as shown in FIG. 16, the process can use a mechanical
cutting element 90 (e.g., a steel ruled die, or the like) that
comes in contact with the substrate 14 and is designed to penetrate
the polymer substrate. The cutting element 90 can be attached to
the sides of the modular unit 50 via various mechanical means 92.
The cutting edge 94, in this case, would exceed the plane 60 of the
substrate by an amount necessary to achieve cutting. A
corresponding modular unit of the other first or second unit 16'
can provide a bearing surface for the cutting edge 94 or an
additional cutting element 90 to improve the cutting process.
[0060] Each of the modular units 50 will include a number of
conduits and ports for coupling the assemblies 64, 72, 76, 90 to
their respective sources (e.g. power source, gas source, vacuum
source, or the like). FIG. 17 shows a modular unit 50 that has an
internal conduits 96 for drawing vacuum, transporting electrical
energy, transporting gas, or the like. These internal conduits
connect the cavity 20 of the individual modular units 50 to a
movable end unit 36 which has corresponding conduits 97 that are
connectable to connectors, power supplies, pumps and blowers, etc.
needed to provide electricity provide vacuum capabilities, and
provide various gases for processing. Various types of connectors
considered standard in the mechanical equipment industry provide
the connection between the end unit 36 and modular process units
50. As shown by the arrows, the end unit 36 is typically moved
laterally with respect to the processing apparatus 16 in order to
effect a connection (or disengage a connection) with the conduit 96
of the modular unit 50. This movement is computer controlled to be
coordinated with the rotational and linear movement of the
processing apparatus 16 such that at the start of a sequence the
conduits of the processing apparatuses 16, 16' are aligned the end
unit 36. If the processing apparatuses are to be rotated, the end
unit 36 can move away from the processing apparatus 16 and
disengage its various connections. The upper/lower apparatuses are
then raised away from the substrate a sufficient distance to allow
the rotation of the processing apparatus to position the new
processing unit to become oriented directly above or below the
substrate. The substrate can then be moved if a part of an inline
continuous process, removed in the case of a sheet process or
allowed to stay in place for the next process. The first and second
units 16, 16' are then lowered and raised to come in contact with
the substrate. The end unit 36 can then be re-engaged with the
first and second units 16, 16' to connect the conduit 96 to the
desired source.
[0061] An exemplary method of the present invention will now be
described in relation to the manufacturing of an EMI/RFI shield
that is composed of a metallized polymer substrate. In particular,
the following method will be in relation to an in-line process of
metallizing a thermoform. The thermoform can be automatically or
manually roll-fed or sheet-fed into the processing apparatuses of
the present invention. A first station is typically a shaping or
thermoforming station. Thermoforming is the heating and molding of
plastic substrate into a shaped product. The shaped product can
take a variety of forms to create an EMI shield. Various EMI
shields are described and illustrated in U.S. Pat. No. 5,811,050
and patent application Ser. No. 09/788,263, filed Feb. 16, 2001,
entitled "EMI and RFI Shielding for Printed Circuit Boards"
(Attorney Docket No. 020843-000200US) and Ser. No. 09/785,975 filed
Feb. 16, 2001, entitled "Electromagnetic Interference Shielding of
Electrical Cables and Connectors" (Attorney Docket No.
020843-000100US), and PCT Application No. 00/27610, filed Oct. 6,
2000, entitled "EMI Containment Apparatus" (Attorney Docket No.
020843-000300PC), the complete disclosures of which are
incorporated herein by reference.
[0062] The shaping processing apparatus 26 (for example FIG. 3) can
use either a vacuum to pull the polymer sheet into the shape of the
mold and/or air pressure to force the polymer sheet into the shape
of the mold. The present invention can use matched male/female
molds (with or without the vacuum and air pressure) to facilitate
the molding of the polymer. The thermoforming assemblies 16 can use
a variety of heating elements to soften the substrate 14, such as
ceramic, quartz tubes, lamps, coils, or the like. In use, the
thermoforming assembly 26 is moved to contact the polymer substrate
14. The substrate can be heated to the desired softness or "sag"
and can then be formed in the mold on the first and second units.
As noted above, if desired, a vacuum can be coupled to one of the
first and second modules and a pressure source can be coupled to
the other of the first and second modules.
[0063] The shaped substrate can then be transported either manually
or with a conveyor system 32 to the metallization assembly 28. The
metallization assembly 28 can create a vacuum around the desired
portion of the substrate and the metal layer can be deposited onto
the shaped substrate. Thereafter, the metallized substrate can be
moved to the cutting assembly 30 for final processing of the
substrate (FIGS. 15 and 16). While not shown, it should be
appreciated that a variety of pre-conditioning assemblies 64 and
other finishing assemblies can be used to prep and finish the
resulting EMI shield.
[0064] While all the above is a complete description of the
preferred embodiments of the inventions, various alternatives,
modifications, and equivalents may be used. For example, while the
systems of the present invention are illustrated with the
processing unit and substrate in a horizontal position, it should
be appreciated that the substrate can be moved in a vertical
direction, if desired As will be appreciated by those of ordinary
skill in the art, the foregoing description is intended to be
illustrative, but not limiting, of the scope of the invention which
is set forth in the following claims.
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