U.S. patent application number 15/389748 was filed with the patent office on 2017-04-13 for aluminum emi / rf shield.
This patent application is currently assigned to A.K. Stamping Company, Inc.. The applicant listed for this patent is A.K. Stamping Company, Inc.. Invention is credited to Bret Barry, Arthur Kurz, Michael Schneider.
Application Number | 20170105322 15/389748 |
Document ID | / |
Family ID | 51686652 |
Filed Date | 2017-04-13 |
United States Patent
Application |
20170105322 |
Kind Code |
A1 |
Kurz; Arthur ; et
al. |
April 13, 2017 |
Aluminum EMI / RF Shield
Abstract
A shield made from aluminum (AL) or an aluminum-based alloy
coated with a solderable plating such as nickel or tin provides
thermal improvement over existing shielding materials. The shield
for circuitry on a circuit board comprising an aluminum material
plated with a solderable material, the shield providing
electromagnetic interference and radio frequency interference
shielding and heat transfer when positioned over a circuit.
Inventors: |
Kurz; Arthur; (New Vernon,
NJ) ; Schneider; Michael; (Montgomery, NJ) ;
Barry; Bret; (Fincastle, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
A.K. Stamping Company, Inc. |
Mountainside |
NJ |
US |
|
|
Assignee: |
A.K. Stamping Company, Inc.
Mountainside
NJ
|
Family ID: |
51686652 |
Appl. No.: |
15/389748 |
Filed: |
December 23, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14210561 |
Mar 14, 2014 |
9538693 |
|
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15389748 |
|
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61788151 |
Mar 15, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 23/3672 20130101;
H05K 7/2039 20130101; H01L 2924/0002 20130101; H05K 9/0026
20130101; H05K 9/0081 20130101; H01L 23/552 20130101; H05K 9/0032
20130101; H01L 2924/00 20130101; H01L 2924/0002 20130101 |
International
Class: |
H05K 9/00 20060101
H05K009/00; H01L 23/367 20060101 H01L023/367; H01L 23/552 20060101
H01L023/552; H05K 7/20 20060101 H05K007/20 |
Claims
1. A shield attached to a circuit board for providing
electromagnetic interference and radio frequency interference
shielding and heat transfer when positioned over a circuit, the
shield comprising: aluminum plated with a solderable material.
2. The shield of claim 1, wherein the aluminum comprises an
aluminum based alloy.
3. The shield of claim 1, wherein the solderable material comprises
at least one of nickel or tin.
4. The shield of claim 1, wherein the shield comprises a top wall
and one or more side walls.
5. The shield of claim 4, further comprising heat dissipating fins
attached to the top wall of the shield.
6. The shield of claim 1, wherein the shield is a one piece
shield.
7. The shield of claim 1, wherein the shield is a two piece shield
comprising a fence and a lid attached to the fence.
8. The shield of claim 1, wherein the shield is peelable.
9. The shield of claim 1, wherein the shield is non-peelable.
10. A circuit shield assembly comprising: a circuit board including
circuitry thereon; a shield containing aluminum plated with a
solderable material, the shield attached to the circuit board
enclosing at least a portion of the circuitry, the shield
transferring heat generated by the circuitry from a top surface of
the shield to the circuit board, the shield providing
electromagnetic interference and radio frequency interference
shielding.
11. The shield of claim 10, wherein the aluminum comprises an
aluminum based alloy.
12. The shield of claim 10, wherein the solderable material
comprises at least one of nickel or tin.
13. The shield of claim 10, wherein the shield comprises a top wall
and one or more side walls.
14. The shield of claim 13, wherein the shield further comprises
heat dissipating fins attached to the top wall.
15. The shield assembly of claim 13, wherein heat is transferred
from the top wall of the shield down side walls of the shield.
16. The shield of claim 10, wherein the shield is a one piece
shield.
17. The shield of claim 10, wherein the shield is a two piece
shield comprising a fence and a lid attached to the fence.
18. The shield assembly of claim 17, wherein the fence is attached
the circuit board and surrounds at least a portion of the
circuitry.
19. The shield of claim 10, wherein the shield is peelable.
20. The shield of claim 10, wherein the shield is non-peelable.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of, and claims the
benefit of priority to, U.S. patent application Ser. No. 14/210,561
filed on Mar. 14, 2014, now U.S. Pat. No. 9,538,693, which claims
priority to U.S. Provisional Patent Application No. 61/788,151
filed on Mar. 15, 2013, the entire disclosures of which is
expressly incorporated herein by reference.
BACKGROUND
[0002] Field
[0003] The present disclosure relates to an EMI/RF shield for
circuitry on a circuit board and more particularly an EMI/RF shield
comprised of aluminum or an aluminum-based alloy and plated with a
solderable material.
[0004] Related Art
[0005] Traditional EMI/RF shielding materials include but are not
limited to nickel silver, tin plated cold rolled steel or SPTE,
stainless steel, brass, or phosphor bronze materials which are good
for formability and EMI/RF shielding but are poor from a thermal
performance perspective or cost prohibitive for a shielding
application.
[0006] One piece shields are typically used on thin devices where
the height is a concern and replaceable lids cannot be used due to
height restrictions. One piece shields are also used for cost
saving solutions when compared to two piece shields. Two piece
shielding solutions are generally used for reworkability and
testing, and are typically higher cost.
SUMMARY
[0007] A shield made from aluminum (AL) or an aluminum-based alloy
coated with a solderable plating such as nickel or tin provides
thermal improvement over existing shielding materials. Plated
aluminum offers enhanced thermal performance while also offering a
significant weight reduction when compared to commonly used
shielding materials. Aluminum in its raw form is not a solderable
material but can be pre-processed and/or post-processed with a
solderable plating allowing the shield to be soldered directly to a
circuit board. The aluminum-based shield helps spread heat
generated from a device (IC) across the top surface of the EMI lid
flattening out "hot spots." Due to the higher thermal conductivity
of aluminum and the ability to solder the shield directly to the
board, the shield will also transfer heat from the top surface down
the shield side walls and "dump" the heat into the circuit board.
Circuit boards constructed using layers of copper traces will
transfer heat away from the device offering a lower operating
temperature improving device life and reliability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The foregoing features will be apparent from the following
Detailed Description, taken in connection with the accompanying
drawings, in which:
[0009] FIG. 1 is a side view of a two-piece EMI/RF shield
consisting of a fence and lid;
[0010] FIG. 2 is a perspective view showing two two-piece EMI/RF
shields each with a lid attached to a fence around circuitry on a
board;
[0011] FIG. 3 is a perspective view showing a one piece reworkable
shield that can be attached directly to a circuit board;
[0012] FIG. 4 is a side view of another EMI/RF shield with heat
dissipating fins attached to the shield;
[0013] FIG. 5 is a perspective view of the shield shown in FIG.
4;
[0014] FIG. 6 is a perspective view of an EMI/RF shield with heat
fins thereon; and
[0015] FIG. 7 is a perspective view of a EMI/RF shield with heat
fins thereon.
DETAILED DESCRIPTION
[0016] An EMI/RF shield is made of aluminum or an aluminum-based
alloy to take advantage of the thermal performance of aluminum. To
allow for soldering, the aluminum material is plated with a
solderable material such as nickel or tin.
[0017] FIG. 1 is a side view of a heat shield made of aluminum or
an aluminum-based alloy, generally indicated at 10. The shield lid
10 is attached to a fence 9 which is attached to a circuit board
and surrounds circuitry. Other ways of attachment of the shield 10
to a circuit board circuitry are considered to be written within
the scope of this disclosure. The shield 10 includes an upper
surface 20 and may include one or more side walls 30, forming a lid
that can be positioned over a circuit to provide for
electromagnetic interference and radio frequency shielding. For
example, the shield could have four walls and a top wall to form a
five-sided lid. A benefit of using aluminum or an aluminum-based
alloy is the enhanced thermal performance and weight reduction as
compared to other shielding materials. Because of the thermal
conductivity of the aluminum, the shield transfers heat from the
top surface down the side walls of the shield and can dump the heat
into the circuit board where it is dissipated.
[0018] FIG. 2 is a perspective view showing two fences 9 on a
circuit board 8 with shields lids 10 attached to the fences 9. All
of the shields discussed herein could be one or two piece shields
that could be attached to circuit boards by attachment to fences or
in other ways known in the art. The shield can be attached to the
fencing in any way known in the art, such as by soldering. The
attachment can be snap down or as otherwise know in the art. The
shields 10 include top wall 20 and side walls 30. The shields lids
10 are made of an aluminum or aluminum-based alloy plated with a
solderable material such as nickel or tin. The fence 9 can be made
of aluminum or an aluminum-based alloy plated with a solderable
material such as nickel or tin to permit soldering of the shield.
The aluminum containing shields disclosed herein can be
manufactured in accordance with what is known in the art in
connection with manufacturing shields of conventional shielding
materials. The aluminum material can be plated with nickel, tin or
another solderable material before or after being formed into a lid
configuration.
[0019] FIG. 3 is a perspective view showing a one piece reworkable
shield 10A that could be made of aluminum or an aluminum-based
alloy that can be attached directly to a circuit board. The shield
10A includes top wall 20A and side walls 30A. The shield 10A is
made of aluminum or an aluminum-based alloy plated with a
solderable material such as nickel or tin to permit soldering of
the shield directly to the circuit board. The fence 9 are made of
aluminum or an aluminum-based alloy plated with a solderable
material such as nickel or tin to permit soldering of the shield.
The aluminum containing shields disclosed herein can be
manufactured in accordance with what is known in the art in
connection with manufacturing shields of conventional shielding
materials. The aluminum material can be plated with nickel, tin or
another solderable material before or after being formed into a
configuration with side walls. The shield could be peelable or
non-peel. If it is a peel shield and if it is re-worked and the lid
is removed, the fence is left behind attached to the board
requiring a replacement lid that snaps on the existing fence.
[0020] FIG. 4 shows a shield generally indicated at 110 attached to
a fence 9. The shield has a top wall 120 and may have one or more
side walls 130. The shield includes heat dissipating fins generally
indicated at 140 attached to the top wall. The fins 140 can be
soldered to the top wall 120 of the shield 110. The fins can be
made of the same material as the shield, e.g. aluminum or an
aluminum-based alloy that can be plated with nickel, tin or other
solderable material. Of course the fins can be made of an entirely
different material than the shield, such as a conventional
non-aluminum material, if desired. The fins can be shaped as
desired in accordance with what is known in the art. The fins could
be plated with a solderable material before or after the fins are
shaped into final form. As shown in FIG. 4, fins 140 can have a
series of valleys 142 for contact to and solderable connection with
the top wall 120 of shield 110. The fins 140 can have a plurality
of upstanding walls 144 and tops 146 connected between upstanding
walls. Upstanding walls 144 can have further heat dissipating
features such as further fins 148 to provide greater surface area
for increased heat dissipation.
[0021] FIG. 5 is a perspective view of the shield with fins shown
in FIG. 4. As discussed with respect to FIG. 3, the shield 110
includes a top 120 and may include side walls 130. The shield 110
is attached to fence 9 on a circuit board. Fins 140 include a
series of valleys 142 wherein the fins 140 can be soldered to the
top wall 120, a plurality of upstanding walls 144 and a plurality
of top surfaces 146 which interconnect adjacent upstanding walls
144. Further, upstanding walls 144 may include further heat
dissipation features such as additional fins 148.
[0022] FIG. 6 is a perspective view of another aluminum or
aluminum-based shield with fins. The shields 210 includes a top
wall 220 and may include side walls 230. The shields 210 are
attached to fences 9 on a circuit board 8. Fins 240 include a
series of valleys 242 that can be soldered to the top wall 220, a
plurality of upstanding walls 244 and a plurality of top surfaces
246 which interconnect adjacent upstanding walls 244. As shown, the
upstanding walls 244 can be configured to extend at right angles
with respect to the top wall 220.
[0023] FIG. 7 is a perspective view of another aluminum or
aluminum-based shield with fins. The shield 310 includes a top wall
320 and may include side walls 330. The shield 310 is attached to
fence 9 on a circuit board. Fins 340 include a series of valleys
342 wherein the fins 340 can be soldered to the top wall 320, a
plurality of upstanding walls 344 and a plurality of top surfaces
346 which interconnect adjacent upstanding walls 344. As shown, the
upstanding walls 344 of fins 340 can be configured to extend from
the top wall at an angle other than a right angle from the top wall
320. Further, upstanding walls 344 may include further heat
dissipation features such as additional fins 348.
[0024] The shields disclosed herein can be: single piece shields
that are non-peelable or non-reworkable; single piece shields that
are peelable/reworkable; two piece shields including a fence and
lid both made using plated aluminum; two piece shields including a
fence and lid, one component of which is plated aluminum (typically
the lid) (the fence could use nickel silver, cold rolled steel or
plated stainless steel); and two piece shields with soldered pre-
or post-plated aluminum or copper (not limited to material
selection) fin stock soldered to plated lid surface.
[0025] Low profile/low power devices such as mobile handsets,
tablets, thin laptops may use either a one or two piece shield
solution without soldered fin stock to the lid offering a thermal
advantage over commonly used nickel silver and cold rolled
shields.
[0026] High power applications such as RF modules, processor
modules which typically are found in larger case structures (e.g.
server chassis, wireless modems, set top boxes or cable boxes)
which are typically force convection cooled. These devices can use
plated fin stock to offer additional thermal improvement when used
with the base plated aluminum fence and lid. Fin stock (formed,
folded, stamped, etc.) is soldered to the top surface of the EMI/RF
shield lid increasing thermal performance.
[0027] Having thus described the disclosure in detail, it is to be
understood that the foregoing description is not intended to limit
the spirit or scope thereof. It will be understood that the
embodiments of the present disclosure described herein are merely
exemplary and that a person skilled in the art may make any
variations and modification without departing from the spirit and
scope of the disclosure. All such variations and modifications,
including those discussed above, are intended to be included within
the scope of the disclosure. What is desired to be protected is set
forth in the following claims.
* * * * *