U.S. patent application number 16/839625 was filed with the patent office on 2021-10-07 for air duct with emi suppression.
The applicant listed for this patent is QUANTA COMPUTER INC.. Invention is credited to Ching-Jen CHEN, Cheng-Hsien LEE.
Application Number | 20210315136 16/839625 |
Document ID | / |
Family ID | 1000004777479 |
Filed Date | 2021-10-07 |
United States Patent
Application |
20210315136 |
Kind Code |
A1 |
CHEN; Ching-Jen ; et
al. |
October 7, 2021 |
AIR DUCT WITH EMI SUPPRESSION
Abstract
An air duct formed from an electromagnetic wave absorber in the
form of a sheet is disclosed. The sheet can be bent into a duct or
scored, and folded at the score lines to bring the ends of the
sheet into proximity. The ends can then be joined by adhesive,
welding, or mechanical fasters. The air ducts disclosed herein
provide dual functions of providing ventilation for electronic
components in an electronic module, while at the same time,
reducing electromagnetic interference (EMI). One or more air ducts,
of the same or different dimensions, shapes, volumes can be
combined with electronic modules, such as a server, to provide both
ventilation and EMI suppression to various components within the
electronic module.
Inventors: |
CHEN; Ching-Jen; (Taoyuan
City, TW) ; LEE; Cheng-Hsien; (Taoyuan City,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUANTA COMPUTER INC. |
Taoyuan City |
|
TW |
|
|
Family ID: |
1000004777479 |
Appl. No.: |
16/839625 |
Filed: |
April 3, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05K 7/1487 20130101;
H05K 7/20709 20130101; H05K 7/20009 20130101; H01Q 17/008 20130101;
H05K 9/0041 20130101; H01Q 17/004 20130101 |
International
Class: |
H05K 9/00 20060101
H05K009/00; H01Q 17/00 20060101 H01Q017/00; H05K 7/20 20060101
H05K007/20; H05K 7/14 20060101 H05K007/14 |
Claims
1. An air duct capable of both ventilating an electronic device and
reducing electromagnetic interference (EMI) to the electronic
device; the air duct comprising at least one wall consisting of an
electromagnetic interference (EMI) wave absorber sheet; the sheet
comprising a soft ferrite having its surface treated with a silane
with no functional group, magnetite and silicone, and the sheet
configured to absorb radio frequency waves so as to reduce
electromagnetic interference (EMI); wherein the electromagnetic
interference (EMI) wave absorber has a permeability (.mu.') where
.mu.'=150 (at 1 MHz); and wherein the at least one wall consisting
of the electromagnetic interference (EMI) sheet is configured as
part of a conduit to convey ventilating air to the electronic
device.
2. (canceled)
3. The air duct of claim 1, further comprising a plurality of walls
formed of the electromagnetic wave absorber.
4. The air duct of claim 1, wherein the at least one wall can
absorb over a radio frequency range of 50 MHz to 10 GHz.
5. The air duct of claim 1, wherein the at least one wall comprises
a thickness in the range of 0.10 mm to 0.50 mm.
6. A combination of the air duct of claim 1, and an electronic
module, wherein the electronic module comprises at least a central
processing unit (CPU).
7. The combination of claim 6, comprising at least one other
electronic component.
8. The air duct of claim 1, wherein the at least one wall of the
air duct is formed of an electromagnetic interference (EMI) sheet
absorber further comprising flat, soft magnetic powder.
9. The air duct of claim 8, where the air duct comprises a single
wall wherein the electromagnetic interference (EMI) wave absorber
sheet has two ends which are brought into proximity and joined.
10. The air duct of claim 8, wherein the electromagnetic
interference (EMI) absorber sheet comprises a plurality of score
lines, and the sheet is folded at the score lines to form the air
duct.
11. The air duct of claim 9, wherein the two ends are joined by at
least one selected from the group consisting of an adhesive,
welding, and mechanical fasteners.
12. The air duct of claim 1, wherein the at least one wall is a
non-linear shape.
13. The air duct of claim 1, wherein the at least one wall is
assembled from a plurality of different pieces of an
electromagnetic wave absorber whose pieces are joined together to
form the air duct.
14. (canceled)
15. A combination of the air duct of claim 1, and an electronic
module comprising at least a central processing unit (CPU).
16. The combination of claim 15, comprising at least one other
electronic component other than the central processing unit
(CPU).
17. The combination of claim 16, comprising multiple air ducts.
18. The combination of claim 17, wherein at least one air duct of
the multiple air ducts, differs in at least one category selected
from the group consisting of size, shape, and volumetric flow, from
at least one other air duct of the multiple air ducts.
Description
FIELD OF THE INVENTION
[0001] This disclosure relates to air ducts for ventilating
electronic devices, where the air ducts have dual functioning
properties. Air ducts are commonly used for ventilating electronic
devices, such as electronic components in a chassis. The present
disclosure provides for ventilating electronic devices, while at
the same time, suppressing electromagnetic interference ("EMI") in
a wide frequency range.
BACKGROUND
[0002] U.S. published application 20030202326 A1, entitled
"Electromagnetic interference reduction air duct" describes an air
duct for ventilating an electronic device having a processor. The
air duct comprises one or more walls that have an irregular surface
and that further have a layer of conductive material applied to the
irregular surface. Further embodiments of this disclosure include
electronic device enclosures and electronic devices having an air
duct featuring an irregular interior surface, and having conductive
material applied to the irregular surface. In other words, a
conductive paint converts the air duct into a parallel wave-guide.
The air duct generally has a "cut-off frequency," where
electromagnetic waves with a frequency that is lower than the
cut-off frequency will not propagate at all. Thus, the wave with a
frequency lower than the cut-off frequency will cause exponential
attenuation (electromagnetic interference reduction) that is
dependent upon the length of the guide.
[0003] The drawback of this previous approach is that the cut-off
frequency depends upon the size of the air duct. Thus, this
waveguide is only used for microwave frequencies. For lower
frequencies, the size of the air duct is not within normal
dimensions to function as a ventilating device for electronic
components.
[0004] Recently introduced electromagnetic absorbing products can
provide a relatively easy solution for reducing unwanted radio
frequency ("RF") noise. These sheet-type absorbing products are a
composite material with magnetic particles embedded in a polymer.
They have good noise attenuation properties from hundreds of MHz to
several GHz. These materials have unique electromagnetic and
physical properties.
[0005] JP-A-2002-329995 discloses a laminated electromagnetic wave
absorber composed of an electromagnetic wave reflection layer
coated, at least on one side, with an electromagnetic wave
absorption layer. The reflection layer comprises an
electroconductive filler dispersed in a silicone resin, and the
absorption layer comprises an electromagnetic wave absorbing filler
dispersed in a silicone resin. It is claimed to have high
electromagnetic wave absorbing and shielding capacities, and at the
same time, high moldability and flexibility. Weather resistance and
heat resistance are attributable to the silicone resin itself.
JP-A-11-335472 discloses a sheet of electromagnetic wave absorbing,
thermoconductive, silicone gel composition containing magnetic
particles of metal oxide (e.g., ferrite), and a thermoconductive
filler (of metal oxide or the like).
[0006] JP-A-2000-342615 discloses a method for producing a
composite magnetic film of flat, soft magnetic powder slurried with
a binder and solvent. However, it is difficult for this method to
have a film of high, flat, soft magnetic powder content. Therefore,
this film cannot be expected to have a high permeability at a high
frequency of 1 GHz or more. JP-A-2001-294752 and JP-A-2001-119189
disclose a curable silicone composition which allows a soft,
magnetic material to be well formed even when it contains a soft,
magnetic powder at a high content to have excellent electromagnetic
wave absorption characteristics. These compositions, however,
involve problems of insufficient soft, magnetic particle content
and moldability. JP-A-2002-15905 discloses a composite magnetic
material for absorbing electromagnetic waves. The composite
magnetic material contains a flat, soft magnetic powder having an
aspect ratio of 20 or more, ferrite powder having a particle size
of 100 .mu.m or less and resin binder, where the magnetic powder
has a well-balanced complex permeability and complex dielectric
constant to realize efficient conversion of noise into heat energy
at a high frequency.
[0007] U.S. published application 2070196671 A1 discloses several
embodiments of wave absorbers. In one embodiment, the wave absorber
comprises: (a) soft ferrite having its surface treated with a
silane compound having no functional group, (b) flat, soft magnetic
metal powder, (c) magnetite, and (d) silicone. In another
embodiment, it omits (b) the flat, soft magnetic powder and
comprises only (a) soft ferrite having its surface treated with a
silane compound having no functional group, (c) magnetite and (d)
silicone. In either embodiment, the electromagnetic wave absorbers
are said to excel in electromagnetic wave absorption, heat
conduction and flame resistance, exhibiting less temperature
dependence, and which electromagnetic wave absorber is soft,
excelling in adhesion strength and further excelling in high
resistance, high insulation properties and in energy conversion
efficiency being stable in MHz to 10 GHz broadband frequency. Each
of the foregoing prior art disclosures is herein incorporated by
reference in their entirety.
SUMMARY
[0008] The term "embodiment" and like terms used herein are
intended to refer broadly to all the subject matter of this
disclosure and the claims below. Statements containing these terms
should be understood not to limit the subject matter described
herein or to limit the meaning or scope of the claims below.
Embodiments of the present disclosure covered herein are defined by
the claims below, not this summary. This summary is a high-level
overview of various aspects of the disclosure and introduces some
of the concepts that are further described in the Detailed
Description section below. This summary is not intended to identify
key or essential features of the claimed subject matter; nor is it
intended to be used in isolation to determine the scope of the
claimed subject matter. The subject matter should be understood by
reference to appropriate portions of the specification of this
disclosure, any or all drawings, and each claim.
[0009] Because of the varied and emerging requirements for air
ducts for electronic modules, we contemplate that our disclosure
can provide the following: [0010] In one embodiment, we provide an
air duct capable of the dual purposes of ventilating an electronic
device and reducing electromagnetic interference (EMI). The air
duct comprises at least one wall formed of an electromagnetic wave
absorber. [0011] In another embodiment, the at least one wall
further comprises a flat, soft magnetic powder. [0012] In a still
further embodiment, the air duct comprising multiple walls formed
of an electromagnetic wave absorber comprising a soft ferrite
treated with a silane having no functional group, magnetite, and
silicon. [0013] In another embodiment, the at least one wall can
absorb over a broad frequency range of 50 MHz to 10 GHz. [0014] In
another embodiment, the at least one wall comprises a thickness in
the range of 0.10 mm to 0.50 mm.
[0015] It is a still further embodiment to provide a plurality of
electronic devices within a single module, such as a server or
chassis, where the ventilation of the electronic devices is
provided by one or more air ducts having the 2-in-1 functional
properties as described above. [0016] In one embodiment, we
describe a combination of the air duct of described in paragraph
[0010] above, and an electronic module, wherein the electronic
module comprises at least a central processing unit (CPU). [0017]
In another embodiment, the electronic module comprises at least a
central processing unit (CPU) and at least one other electronic
component. [0018] In a still further embodiment, the electronic
module comprises at least a central processing unit (CPU), wherein
a plurality of air ducts as described in paragraph [0010] above are
provided. [0019] In a still further embodiment, at least one of the
air ducts in the plurality of air ducts differs from another air
duct in at least one of size, shape, and volumetric flow.
[0020] It is a further embodiment of this disclosure to utilize an
EMI absorber sheet to make an air duct, where the performance
advantage comes from dual (2-in-1) functional properties of
ventilating an electronic device and EMI suppression in a wide
frequency range, and further, where the size of the air duct is
flexible to meet thermal dissipation requirements of different
electronic devices.
[0021] The above summary is not intended to represent every
embodiment or every aspect of the present disclosure. Rather, the
foregoing summary merely provides examples of some of the novel
aspects and features set forth herein. The above features and
advantages, and other features and advantages of the present
disclosure will be readily apparent from the following detailed
description of representative embodiments and modes for carrying
out the present invention, when taken in connection with the
accompanying drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The disclosure, and its advantages and drawings, will be
better understood from the following description of exemplary
embodiment, and are therefore not to be considered as limitations
on the scope of the various embodiments or claims.
[0023] FIG. 1 is a schematic representation of an EMI absorber
sheet blank.
[0024] FIG. 2 is a schematic representation of the EMI absorber
sheet blank of FIG. 1 with score lines to facilitate folding of the
blank into a quadrilateral shaped air duct.
[0025] FIG. 3 is a schematic representation of an air duct formed
by folding along the score lines of FIG. 2.
[0026] FIG. 4 is a graphical representation of permeability, where
.mu.=150 (at 1 MHz) as the ordinate plotted against frequency as
the abscissa.
[0027] FIG. 5 is a graphic representation of typical power loss
change as the ordinate plotted against frequency (GHz) for various
thicknesses.
[0028] FIG. 6 is a schematic, perspective view of an air duct,
according to one embodiment of the disclosure in combination with
at least one electronic device for use in a single chassis (not
shown).
[0029] The present disclosure is susceptible to various
modifications and alternative forms. Some representative
embodiments have been shown by way of example herein. It should be
understood however, that the disclosure is not intended to be
limited to the particular forms illustrated. Rather, the disclosure
is to cover all modifications, equivalents, and alternatives
falling within the spirit and scope of the invention as defined by
the appended claims.
DETAILED DESCRIPTION
[0030] The present inventions can be embodied in many different
forms. Representative embodiments are shown in the drawings, and
will herein be described in detail. These embodiments are examples
or illustrations of the principles of the disclosure but are not
intended to limit its broad aspects. To that extent, elements and
limitations that are disclosed, for example, in the Abstract,
Summary and Detailed Description sections, but not explicitly set
forth in the claims, should not be incorporated into the claims,
singly or collectively, by implication, inference, or otherwise.
For purposes of the present detailed description, unless otherwise
specifically disclaimed, the singular includes the plural and vice
versa, and the word "including" means "including without
limitation." Moreover, words of approximation, such as "about,"
"almost," "substantially," "approximately," and the like, can be
used herein to mean "at," "near," or "nearly at," or "within 3-5%
of," or "within acceptable manufacturing tolerances," or any
logical combination thereof. Like elements in various views of the
drawings are given the same numerical identifier.
[0031] An EMI absorber sheet 10 before being shaped into an air
duct is illustrated schematically in FIG. 1. The EMI absorber sheet
10 can be formed in various ways, or even purchased commercially.
In one embodiment, the EMI absorber sheet 10 comprises a soft
ferrite having its surface treated with a silane compound having no
functional group, magnetite, and silicone. In another embodiment,
the EMI absorber sheet 10 can comprise a soft ferrite having its
surface treated with a silane compound having no functional group,
flat, soft magnetic powder, magnetite, and silicone. For example,
the EMI absorber sheet 10 may be curved about itself, and fastened
at its adjacent edges to form a tubular air duct having a singular
wall, such as an air duct of tubular cross-section. In such an
embodiment, the air duct can be said to comprise only a single
wall. However, in preferred embodiments, the EMI absorber sheet 10
can be formed into a conduit shape comprising a plurality of
walls.
[0032] As shown in FIG. 2, the EMI absorber sheet 10 can be formed
into an air duct by providing a series of score lines 14, 18 to
assist in converting the EMI absorber sheet 10 into a pre-folded,
scored EMI absorber sheet 12. The scored EMI absorber sheet 12 is
formed into sections 11, 13 and 17, as defined by the score lines
14, 18. These sections 11, 13 and 17 will then define the shape of
the air duct.
[0033] The scored EMI absorber sheet 12 can then be folded in the
direction of arrow 20 to form an air duct 30, as shown in FIG. 3.
Section 13 form the top wall of air duct 30, while sections 17 and
11 form the left and right side walls of air duct 30. The adjacent
edges of sections 17 and 11 can be joined at their intersection 32
by gluing, welding, mechanical fasteners, or other means known in
the art. Also, as shown in FIG. 3, the number, size and shape of
the sections will determine the number of walls and ultimate shape
of air duct 30. In this example, there are three rectangular
sections 11, 13 and 17 that form three linear walls for the air
duct 30. The walls of the air duct formed by the EMI absorber sheet
blank 10 may also be a non-linear shape (e.g., curvilinear), such
as a single wall forming a pipe-like structure. In other
embodiments of this disclosure, the EMI absorber sheet 10 (in FIG.
1) can be scored in two, three, four, five, six seven, eight, nine,
or more times to form a multi-walled shape. Examples of the
cross-sectional shapes of air ducts so formed upon folding on the
score lines include a triangle, a quadrilateral, a pentagon, a
hexagon, a heptagon, an octagon, a nonagon, a decagon, etc. The
quadrilaterals can include square, rectangular, parallelogram,
trapezoid, isosceles trapezoid, kite and rhombus cross sections,
among others. It should be understood however, that all the
foregoing embodiments are exemplary and not limiting of the shape
of air duct 30. By the use of curved score lines, or by combining
straight and curved score lines, various non-linear air duct shapes
may be achieved, including those with only two walls.
[0034] Alternatively, the air duct may be formed from individual
pieces of an EMI absorber sheet similar to the EMI absorber sheet
10 in FIG. 1, where individual pieces are fastened together to form
the air duct. Fastening can be achieved in various manners, such as
by gluing, welding, stapling, clipping, and other manners of
joining the pieces together. When utilizing individual pieces,
rather than folded blanks, the shape, size and interior volumes of
air ducts can be freely designed to accommodate the ventilating
requirements of the air duct. Even the fitting of the air duct
within the confines of an electronic device or module, such as a
server, can be accommodated.
[0035] The present disclosure also contemplates the formation of
multiple air ducts within a single electronic device, such as a
server. Because electronic devices may vary in the cooling
requirements, air flow volumes and other characteristics unique to
electronic apparatus construction and or configuration, the
multiple air ducts may or may not be of the same shape, size, air
flow capacity, etc.
[0036] In one embodiment, using CA150-030 absorber sheet to make an
air duct, the absorber thickness is 0.30 mm, permeability .mu.'=150
(at 1 MHz) as is shown in FIG. 4. The permeability is complex and
is generally written as .mu.=.mu.'-j.mu.''. The real (.mu.') and
imaginary parts (.mu.'') represent magnetic storage and magnetic
losses, respectively. Performance advantages come from the dual (2
in 1) functional properties when absorber sheet 10 is used for
ventilating an electronic device, as well as for EMI suppression.
FIG. 4 is a graphical representation of permeability of a CA150-030
sheet used to make an air duct. The effect of frequency can be seen
in the graphical representation of FIG. 4 where the frequency (MHz)
on the abscissa is plotted against the permeability (on the
ordinate) of the graph.
[0037] The EMI absorber sheet 10 can be of various thicknesses. For
example, the EMI absorber sheet 10 can have a thickness in the
range of 0.10 mm to 0.50 mm, in varying 0.10 mm increments. For
example, the EMI absorber sheet 10 can have a thickness selected
from 0.10 mm, 0.20 mm, 0.30 mm, 0.40 mm and 0.50 mm. In FIG. 5,
typical power loss change is plotted versus frequency for various
thicknesses of absorbers. EMI absorbing performance over a broad
range of frequency range of 50 MHz to 10 GHz, and more, is
possible. For example, CA150-030 is an absorber having a thickness
0.30 mm, and CA150-050 is an absorber having a thickness of 0.50
mm, respectively. Power loss changes with thickness of absorber
sheet, as well as the frequency. Graphical results are shown in
FIG. 5 for a range of frequencies of 50 MHz to 10 GHz, for various
absorbers, such as CA150-010, CA150-020, CA150-030, CA150-040 and
CA150-050.
[0038] The graphical representations of power loss are seen in FIG.
5, where the frequency range (50 MHz to 10 GHZ) is plotted on the
abscissa for absorber sheets of varying thicknesses of 0.10 mm,
0.20 mm, 0.30 mm, 0.40 mm and 0.50 mm, respectively. The
permeability and power loss changes can be modified by changing the
amount, and/or, relative proportions of the various constituents
used in EMI absorber sheet 10.
[0039] FIG. 6 shows an environment where the dual (2 in 1) function
of air ducts made according to the present disclosure can be
utilized. FIG. 6 shows an electronic module 40, comprising a
printed circuit board ("PCB") 41 in combination with one or more
electronic devices 44, 46. Devices 44, 46, may be independently
chosen from a central control unit ("CPU"), a power supply, a
graphics card, and other electronic components typically found in
servers. The devices 44, 46 are carried by a chassis 48. In the
embodiment of FIG. 6, two air ducts 50, 52 are utilized to
supplying ventilation, such as cooling air, to the various
electronic components within electronic module 40. These air ducts
50, 52 can be the (2 in 1) function air ducts 30 previously
described as providing both ventilation and EMI suppression to the
components within the electronic module 40. Because the design of
electronic modules is in a constant state of flux, applicant has
only exemplified a single current form of electronic module 40.
However, processing speeds and requirements are rapidly improving
for such electronic modules. The present disclosure is designed to
meet both current and future needs for ventilating such electronic
modules. Higher processing speeds generally result in higher power
requirements and greater need for ventilation. Because not all
electronic components within a single electronic module require the
same amount, or degree, of ventilation, it is envisioned that
multiple air ducts of various shapes, sizes, air flow and EMI
suppression specifications will likely exist within a single
electronic module. The present disclosure contemplates the
provision of air ducts to meet all such requirements.
[0040] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art. Furthermore, terms,
such as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art, and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
[0041] Although the invention has been illustrated and described
with respect to one or more implementations, equivalents,
alterations and modifications will occur or be known to others
skilled in the art upon the reading and understanding of this
specification and the annexed drawings. In addition, while a
particular feature of the invention may have been disclosed with
respect to only one of several implementations, such feature may be
combined with one or more other features of the other
implementations as may be desired and advantageous for any given or
particular application.
[0042] The previous description of the disclosure is provided to
enable any person skilled in the art to make or use the disclosure.
Various modifications to the disclosure will be readily apparent to
those skilled in the art, and the generic principles defined herein
can be applied to other variations without departing from the scope
of the disclosure. Thus, the disclosure is not intended to be
limited to the examples and designs described herein, but is to be
accorded the widest scope consistent with the principles and novel
features disclosed herein.
* * * * *