U.S. patent application number 17/684560 was filed with the patent office on 2022-09-29 for method for manufacturing electromagnetic shielding film.
The applicant listed for this patent is Avary Holding (Shenzhen) Co., Limited., QING DING PRECISION ELECTRONICS (HUAIAN) CO.,LTD. Invention is credited to MING-JAAN HO, HSIAO-TING HSU, FU-YUN SHEN.
Application Number | 20220312655 17/684560 |
Document ID | / |
Family ID | 1000006402979 |
Filed Date | 2022-09-29 |
United States Patent
Application |
20220312655 |
Kind Code |
A1 |
SHEN; FU-YUN ; et
al. |
September 29, 2022 |
METHOD FOR MANUFACTURING ELECTROMAGNETIC SHIELDING FILM
Abstract
A method for manufacturing an electromagnetic shielding film
comprising providing an insulating layer, wherein the insulating
layer is metallized to obtain a silver layer; and painting a
conductive adhesive on a surface of the silver layer to form a
conductive adhesive layer. The conductive adhesive layer comprises
bisphenol A diglycidyl ether with a mass percentage between 9.8%
and 10.5%, bisphenol S diglycidyl ether with a mass percentage
between 4.54% and 4.86%, bisphenol F diglycidyl ether with a mass
percentage between 2.27% and 2.43%, polyamide with a mass
percentage between 7.11% and 7.62%, silver copper powder with a
mass percentage between 48.6% and 68.3%, and silver strips with a
mass percentage between 6.44% and 25.9%.
Inventors: |
SHEN; FU-YUN; (Shenzhen,
CN) ; HO; MING-JAAN; (New Taipei, TW) ; HSU;
HSIAO-TING; (New Taipei, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QING DING PRECISION ELECTRONICS (HUAIAN) CO.,LTD
Avary Holding (Shenzhen) Co., Limited. |
Huai an
Shenzhen |
|
CN
CN |
|
|
Family ID: |
1000006402979 |
Appl. No.: |
17/684560 |
Filed: |
March 2, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16021308 |
Jun 28, 2018 |
11297748 |
|
|
17684560 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 27/281 20130101;
B32B 2255/10 20130101; C08L 2205/025 20130101; B32B 2307/212
20130101; H05K 2201/0154 20130101; C09J 9/02 20130101; C08K
2003/0806 20130101; H05K 9/0084 20130101; C08K 2003/085 20130101;
H05K 2201/0715 20130101; H05K 2201/035 20130101; C09J 163/00
20130101; H05K 1/0218 20130101; B32B 2255/205 20130101; B32B 7/12
20130101 |
International
Class: |
H05K 9/00 20060101
H05K009/00; B32B 27/28 20060101 B32B027/28; H05K 1/02 20060101
H05K001/02; C09J 9/02 20060101 C09J009/02; C09J 163/00 20060101
C09J163/00; B32B 7/12 20060101 B32B007/12 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 12, 2018 |
CN |
201810326497.4 |
Claims
1. A method of manufacturing an electromagnetic shielding film,
comprising: providing an insulating layer, wherein the insulating
layer is metallized to obtain a silver layer; painting a conductive
adhesive on a surface of the silver layer to form a conductive
adhesive layer; wherein the conductive adhesive layer comprises
bisphenol A diglycidyl ether with a mass percentage between 9.8%
and 10.5%, bisphenol S diglycidyl ether with a mass percentage
between 4.54% and 4.86%, bisphenol F diglycidyl ether with a mass
percentage between 2.27% and 2.43%, polyamide with a mass
percentage between 7.11% and 7.62%, silver copper powder with a
mass percentage between 48.6% and 68.3%, and silver strips with a
mass percentage between 6.44% and 25.9%; and wherein the sum of the
mass percentages is 100%.
2. The method of claim 1, further comprising: metallizing a copper
layer on the surface of the silver layer to form a metal thick
layer, after the step of forming the silver layer and before the
step of forming the conductive adhesive layer.
3. The method of claim 1, wherein a silverized reagent of the
silver layer is silver nanocrystals, and a main catalyst is
nanosilver.
4. The method of claim 3, wherein the silverized reagent is silver
ion, and the main catalyst comprises AgNO.sub.3,
Ag(NH.sub.3).sub.2NO.sub.3, AgClO.sub.4, and AgOAc.
Description
[0001] This application is a divisional application of a
commonly-assigned application entitled "ELECTROMAGNETIC SHIELDING
FILM", filed on Jun. 28, 2018 with U.S. application Ser. No.
16/021308. The disclosure of the above-identified application is
incorporated herein by reference.
FIELD
[0002] The subject matter relates to electromagnetic shielding.
BACKGROUND
[0003] Electromagnetic interference may arise from external
devices, but shielding may prevent electronic components from being
affected or interfered with. This is an indicator of product
quality. As network communication speeds continue to increase,
portable terminal devices such as smart phones require better and
better shielding against ultrahigh frequency (UHF) signals (1 Ghz
to 50 Ghz). Such shielding is usually through the use of
electromagnetic shielding films installed in electronic devices. In
general, an electromagnetic shielding film comprises a metal layer,
a glue layer, and a protective layer. The protective layer is made
of thermoplastic polyurethane.
[0004] With the miniaturization of electronic components and the
diversification of functions, the size of flexible circuit boards
has been continuously reduced, and the number of layers of the
circuits has been continuously increasing. There is a demand for
the application of electromagnetic shielding films in high-level
environments. However, in a highly stacked flexible circuit board
(greater than 50 microns), the electromagnetic shielding film can
include ruptures or bubbles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Implementations of the present disclosure will now be
described, by way of example only, with reference to the attached
figures.
[0006] FIG. 1 is a flowchart showing a method for manufacturing an
electromagnetic shielding film in accordance with an embodiment of
the present disclosure.
[0007] FIG. 2 is a cross sectional view of an insulating layer of
an embodiment of the present disclosure.
[0008] FIG. 3 a cross sectional view of a metallized insulating
layer (silver) of an embodiment of the present disclosure.
[0009] FIG. 4 is a top view of a conductive layer formed on the
metallized layer of FIG. 3.
[0010] FIG. 5 is a cross sectional view of an electromagnetic
shielding film overlaid on a circuit board.
DETAILED DESCRIPTION
[0011] It will be appreciated that for simplicity and clarity of
illustration, where appropriate, reference numerals have been
repeated among the different figures to indicate corresponding or
analogous elements. In addition, numerous specific details are set
forth in order to provide a thorough understanding of the
embodiments described herein. However, it will be understood by
those of ordinary skill in the art that the embodiments described
herein can be practiced without these specific details.
[0012] In other instances, methods, procedures, and components have
not been described in detail so as not to obscure the related
relevant feature being described. Also, the description is not to
be considered as limiting the scope of the embodiments described
herein. The drawings are not necessarily to scale and the
proportions of certain parts may be exaggerated to better
illustrate details and features of the present disclosure.
[0013] One definition that applies throughout this disclosure will
now be presented.
[0014] The term "substantially" is defined to be essentially
conforming to the particular dimension, shape, or other feature
that the term modifies, such that the component need not be exact.
For example, "substantially rectangular" means that the object
resembles a rectangle, but can have one or more deviations from a
true rectangle.
[0015] The term "comprising," when utilized, means "including, but
not necessarily limited to"; it specifically indicates open-ended
inclusion or membership in the so-described combination, assembly,
series, and the like.
[0016] Referring to the FIG. 1, a method for manufacturing an
electromagnetic shielding film 100 (shown in FIG. 4) is
illustrated. The method is provided by way of example, as there are
a variety of ways to carry out the method. Each block shown in the
figure represents one or more processes, methods, or subroutines,
carried out in the method. Furthermore, the illustrated order of
blocks is by example only, and the order of the blocks can change.
Additional blocks may be added or fewer blocks may be utilized,
without departing from this disclosure. The method can begin at
block 101.
[0017] At block 101, referring to the FIG. 2, an insulating layer
10 is provided.
[0018] The insulating layer 10 comprises a first surface and a
second surface. Typically, the first surface is an upper surface 12
and the second surface is a lower surface 14. The upper surface 12
and the lower surface 14 are the opposite sides of the insulating
layer 10. A thickness of the insulating layer 10 is between 5 and
35 microns. In the embodiment, the insulating layer 10 is made of
polyimide (PI).
[0019] At block 102, referring to the FIG. 3, the insulating layer
10 is metallized to obtain a metal layer 20. A thickness of the
metal layer 20 ranges from 0.1 to 0.5 microns. In the embodiment,
the metal layer 20 is a silver layer. The metallization process
uses silver.
[0020] The upper surface 12 is first subjected to a surface
treatment to form a metallized surface. The surface treatment
comprises any combination of physical oxidation, chemical
oxidation, chemical grafting, electrical grafting, photochemical
grafting, and silanization modification. The metallization
treatment may be any one of electrostatic adsorption or electroless
plating.
[0021] When the electrostatic adsorption is used, the reactants
added are silver nanocrystals (AgNPs), and main component of the
catalyst is nano silver single substance. The upper surface 12
adsorbs AgNPs by charge modification to form the metal layer
20.
[0022] When an ion reaction is used, the added reactant is silver
ion, and the main components of the catalyst are AgNO.sub.3,
Ag(NH.sub.3).sub.2NO.sub.3, AgClO.sub.4, AgOAc. The upper surface
12 adsorbs silver ions by way of charge modification and forms a
metal layer 20 on the upper surface 12 through a series of
reduction reactions.
[0023] In other embodiments, when the ion reaction is used, the
added reactants are silver ions and copper ions. The main
components of the catalyst are AgNO.sub.3 and CuCl.sub.2, and the
upper surface 12 adsorbs silver ions and copper ions through charge
modification, and then a copper-silver alloy is formed on the upper
surface 12 through a series of reduction reactions, to form the
metal layer 20.
[0024] In other embodiments, a copper layer may be further applied
on the metal layer 20 to form a thicker metal layer (not
shown).
[0025] At block 103, referring to the FIG. 4, a conductive adhesive
is applied on the surface of the metal layer 20 to form a
conductive adhesive layer 30, thereby forming an electromagnetic
shielding film 100.
[0026] A thickness of the conductive adhesive layer 30 ranges from
8 to 40 microns. In the embodiment, the conductive adhesive layer
30 comprises bisphenol A diglycidyl ether with a mass percentage
between 9.8% and 10.5%, bisphenol S diglycidyl ether with a mass
percentage between 4.54% and 4.86%, bisphenol F diglycidyl ether
with a mass percentage between 2.27% and 2.43%, polyamide with a
mass percentage between 7.11% and 7.62%, silver copper powder with
a mass percentage between 48.6% and 68.3%, and strips with a mass
percentage between 6.44 and 25.9%. The strips are made of
silver.
[0027] Among the above, the bisphenol A diglycidyl ether is
configured to increase the connectivity, flexibility, and chemical
resistance of the conductive adhesive layer 30. The bisphenol S
diglycidyl ether is configured to increase the connectivity and
heat resistance of the conductive adhesive layer 30. The bisphenol
F diglycidyl ether acts as a bifunctional diluent. The polyamide is
configured as a curing agent. In other embodiments, dicyandiamide
may also be selected as a curing agent. The silver copper powder
and the silver strips all play a role in conducting electricity.
The higher the content of the silver copper powder and the silver
strips, the lower the resistivity of the conductive adhesive layer
30. However, an excessive amount of the powder may cause
unsatisfactory dispersion of the conductive adhesive layer 30, and
poor printing operation performance. Therefore, the content of the
silver copper powder is suggested to be maintained between 48.6%
and 68.3%, and the silver strips content is between 6.44% and
25.9%.
[0028] The following table shows three examples of the conductive
adhesive layer 30 that have been tested to meet the goals described
above.
TABLE-US-00001 EXAMPLE EXAMPLE EXAMPLE Range of EXAMPLE I II III
Ratio DGEBA(Bisphenol 6.5 g 6.5 g 6.5 g 10.0 .+-. 0.3 wt % A
diglycidyl ether) DGEBS (Bisphenol 3.0 g 3.0 g 3.0 g 4.7 .+-. 0.13
wt % S diglycidyl ether) BEF-170(Bisphenol 1.5 g 1.5 g 1.5 g 2.3
.+-. 0.13 wt % F diglycidyl ether) Polyamide 4.7 g 4.7 g 4.7 g 7.4
.+-. 0.3 wt % Silver copper powder 42.4 g 42.4 g 30.0 g 53.3 .+-.
15.0 wt % Silver strip 4.0 g 8.0 g 16 g 16.0 .+-. 10.0 wt % Total
62.1 g 66.1 g 61.7 g 100%
[0029] The bisphenol A diglycidyl ether, bisphenol S diglycidyl
ether, bisphenol F diglycidyl ether, polyamide, silver copper
powder, and silver tablets are mixed and dissolved in a solvent to
form the conductive adhesive layer 30.
[0030] To satisfy the range of the proportions of each component,
the parameter weight of the example can be adjusted, and is not
limited thereto.
[0031] Referring to FIG. 4, the electromagnetic shielding film 100
comprises the insulating layer 10, the metal layer 20, and the
conductive adhesive layer 30. The insulating layer 10 is made of
polyimide. The metal layer 20 is formed on the surface of the
insulating layer 10. The chemical composition of the metal layer 20
is silver. The conductive adhesive layer 30 is coated on the
surface of the metal layer 20. A thickness of the electromagnetic
shielding film 100 is maintained between 13 and 75 microns. The
transverse tensile strength of the electromagnetic shielding film
100 is greater than 160 MPa, and the longitudinal tensile strength
is greater than 130 MPa. The electromagnetic shielding film 100 can
be extended between 60 and 120%. The peeling strength of the
electromagnetic shielding film 100 is greater than 0.6 kg/cm. The
bending limit of the electromagnetic shielding film 100 is more
than 10,000 times.
[0032] Referring to FIG. 5, the electromagnetic shielding film 100
is applied to a circuit board 200 having a high drop. The circuit
board 200 has a height difference, the distance is greater than 0.8
mm, and the height d is in the range of 0-100 microns. The
electromagnetic shielding film 100 is attached to the circuit board
200 and covers the height difference. At this time, the conductive
adhesive layer 30 is attached to the surface of the circuit board
200, and the insulating layer 10 faces away from the circuit board
200. After the electromagnetic shielding film 100 is laid on the
circuit board 200, the thickness of the insulating layer is
maintained between 5 and 35 microns, and the thickness of the metal
layer is maintained between 0.1 and 0.5 microns. The thickness of
the conductive adhesive layer is maintained between 8 and 40
microns.
[0033] The electromagnetic shielding film 100 is manufactured by
metallizing silver and copper on the insulating layer 10
(polyimide) after applying the coating of conductive adhesive. The
electromagnetic shielding film 100 uses the insulating layer 10 as
an outer protective layer, the film 100 has good peel strength,
softness, and low rebound force, so it will not crack or generate
bubbles in a product component. In addition, since the elongation
rate of polyimide is between 70 and 90%. High tear strength of
polyimide makes it less prone to breaking during tear-off of
release papers. Furthermore, PI has lower water absorption
(0.3-0.4%).
[0034] The embodiments shown and described above are only examples.
Many other details are often found in the art. Therefore, many such
details are neither shown nor described. Even though numerous
characteristics and advantages of the present disclosure have been
set forth in the foregoing description, together with details of
the structure and function of the present disclosure, the
disclosure is illustrative only, and changes may be made in the
detail, especially in matters of shape, size, and arrangement of
the parts within the principles of the present disclosure, up to
and including the full extent established by the broad general
meaning of the terms used in the claims. It will therefore be
appreciated that the embodiments described above may be modified
within the scope of the claims.
* * * * *