CN109688781A - Electro-magnetic shielding cover and printed circuit board assembly - Google Patents
Electro-magnetic shielding cover and printed circuit board assembly Download PDFInfo
- Publication number
- CN109688781A CN109688781A CN201910093777.XA CN201910093777A CN109688781A CN 109688781 A CN109688781 A CN 109688781A CN 201910093777 A CN201910093777 A CN 201910093777A CN 109688781 A CN109688781 A CN 109688781A
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- CN
- China
- Prior art keywords
- waveguide
- shielding case
- electro
- shielding
- cover
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0007—Casings
- H05K9/002—Casings with localised screening
- H05K9/0022—Casings with localised screening of components mounted on printed circuit boards [PCB]
- H05K9/0024—Shield cases mounted on a PCB, e.g. cans or caps or conformal shields
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0007—Casings
- H05K9/002—Casings with localised screening
- H05K9/0022—Casings with localised screening of components mounted on printed circuit boards [PCB]
- H05K9/0024—Shield cases mounted on a PCB, e.g. cans or caps or conformal shields
- H05K9/0026—Shield cases mounted on a PCB, e.g. cans or caps or conformal shields integrally formed from metal sheet
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Abstract
The present invention provides a kind of electro-magnetic shielding cover and printed circuit board assemblies.Electro-magnetic shielding cover realizes the effect of electromagnetic shielding for accommodating electric element, the shielding case is made of an electrically conducting material, wherein, the cover of the shielding case is hollow out, each hollow out position forms a waveguide, the axial dimension of the waveguide is the radial dimension of three times of the waveguide or more, the tangential out of plumb of the cover of the shielding case at the axis of the waveguide and waveguide place.Electro-magnetic shielding cover according to the present invention, while realizing electromagnetic shielding using guide filter principle, the hollow structure of waveguide, which is utilized, realizes the function of heat dissipation.
Description
Technical field
The present invention relates to electronic technology fields, and the electromangnetic spectrum of in particular to electronic component, more particularly to use
In the electro-magnetic shielding cover of shielding electromagnetic radiation.
Background technique
By taking pcb board (printed circuit board, also known as printed circuit board) as an example, the part electronic component on pcb board is worked
Cheng Zhonghui fever and/or generation electromagnetic interference (referred to as EMI).The fever of electronic component is so that the raising of pcb board operating temperature, mistake
High temperature will lead to the part electronic component on PCB and can not work normally.Electromagnetic interference may be such that certain on the pcb board
A little electronic components or the other electron component around the pcb board can not work normally.
Therefore in order to guarantee that all electronic components can operate normally and reduce electromagnetic interference on pcb board, lead in the prior art
Can often radiating treatment and shielding processing be subject to the source for generating heat and/or EMI.In most cases, it generates heat on pcb board more
Element simultaneously be also the higher element of EMI intensity, it is therefore desirable to while to fever and electromagnetic interference control.
It is in the prior art usually that will radiate and be electromagnetically shielded the two technical problems to separate and by different technology hands
Section is independently solved.
For example, can integrally add shielding case to pcb board to improve Electro Magnetic Compatibility (EMC) and shield；It can also be with needle
Shielding case is arranged to the regional area of pcb board；But usually used shielding case be all it is closed, closed shielding case hinders member
The heat dissipation of part.In addition, for the shielding case of pcb board integrally closed, high production cost, and cover are usually had gap, seam
Electromagnetic leakage is easily caused at gap.
In another example to increase heat dissipation, common radiating mode includes using fan, installation heat-conducting plate etc..These heat dissipation sides
Formula needs to install additional component, does not only take up biggish space, and higher cost.
Summary of the invention
In view of the above-mentioned prior art state and make the present invention.The purpose of the present invention is to provide one kind to be provided simultaneously with electricity
The electro-magnetic shielding cover of magnetic screen and heat sinking function and printed circuit board assembly with the electro-magnetic shielding cover.
According to the first aspect of the invention, a kind of electro-magnetic shielding cover is provided, is used for accommodating electric element to realize electromagnetism
The effect of shielding, the shielding case are made of an electrically conducting material, wherein
The cover of the shielding case is hollow out, each hollow out position forms a waveguide, the axis of the waveguide
It is the radial dimension of three times of the waveguide or more to size,
The tangential out of plumb of the cover of the shielding case at where the axis of the waveguide and the waveguide.
In at least one embodiment, two adjacent waveguides share a tube wall.
In at least one embodiment, the shielding case is spliced to form by multiple barricades.
In at least one embodiment, the plate face of the axis of the waveguide and the barricade forms inclination angle δ, institute
Inclination angle δ is stated less than 45 degree.
In at least one embodiment, the cross section of the waveguide is in rectangle or hexagon or circle.
In at least one embodiment, the shielding case is made of metal.
In at least one embodiment, the surface of the shielding case is covered with conductive coating.
According to the second aspect of the invention, a kind of printed circuit board assembly is provided comprising printed circuit board and according to this
The invention electro-magnetic shielding cover, the Shielding Case grounding setting,
The shielding case links together with the printed circuit board, and the shielding case will be installed on the printed circuit board
Target electronic components be housed in the inner cavity of the shielding case.
In at least one embodiment, the connector between the shielding case and the printed circuit board forms annular.
In at least one embodiment,
The connector is the pad being made of scolding tin, or
The connector is conducting resinl, or
The connector is conducting foam.
Wave is utilized while realizing electromagnetic shielding using guide filter principle in electro-magnetic shielding cover according to the present invention
The hollow property of conduit realizes the function of heat dissipation simultaneously.
Detailed description of the invention
Fig. 1 is the schematic diagram of shielding case according to embodiment of the present invention.
Fig. 2 is the schematic diagram of a barricade of the shielding case in Fig. 1.
Fig. 3 is the cross-sectional view of the barricade of Fig. 2.
Fig. 4 is the schematic diagram of printed circuit board assembly according to embodiment of the present invention.
Fig. 5 is the schematic diagram of the printed circuit board in Fig. 4.
Description of symbols
10 shielding cases；11 barricades；110 waveguides；12 mounting surfaces；
20PCB plate；21 electric component groups；
30 pads；
A axis；A axial dimension；R radial dimension；The inclination angle δ.
Specific embodiment
Exemplary embodiments of the present invention are described with reference to the accompanying drawings.It should be appreciated that these specific descriptions are only used for
How teaching those skilled in the art implement the present invention, rather than all feasible modes that exhaustion is of the invention, without in
It limits the scope of the invention.
According to guide filter principle, metal tube can be used as high-pass filter, and such metal tube is referred to as waveguide.Wave
Conduit is able to achieve the electromagnetic shielding within the scope of required wave frequency, and frequency passes through lower than the electromagnetic wave of waveguide cutoff frequency to be connect
It will be filtered when the waveguide on ground.Cutoff frequency is related to the shape and size of waveguide, for example, being rectangle for cross section
The relationship of waveguide aperture, cutoff frequency f and rectangle length of long sides b are f (Ghz)=150/b (mm).
The present invention utilizes the above-mentioned characteristic of waveguide, makes electro-magnetic shielding cover (also abbreviation shielding case below).
Referring to Fig.1, the shielding case 10 of present embodiment is in rectangular shape.Five faces in six faces of cuboid are by shielding
Shield plate 11 is constituted, another face is open mounting surface 12, to form housing shape.Mounting surface 12 is used to cooperate with pcb board, peace
The electronic component be electromagnetically shielded loaded on pcb board can be housed in the inner cavity of shielding case 10.
Barricade 11 is made of an electrically conducting material, for example, barricade 11 is made of metal material；Or for example, in insulator
Conductive coating is coated outside manufactured shielding framework to constitute barricade 11.
Referring to Fig. 2 and Fig. 3, the specific structure of barricade 11 is introduced.Barricade 11 is made of multiple waveguides 110.At this
In embodiment, multiple waveguides 110 are arranged together closely to each other, each waveguide 110 is rectangle in cross section
Tubulose, two waveguides 110 adjacent to each other share a tube wall, so that barricade 11 forms reticular structure.
To realize good shield effectiveness, it usually needs the axial length of waveguide is greater than three times of waveguide aperture.For
Save space, it is undesirable to which the thickness of barricade 11 is excessive, therefore in the present embodiment, the axis and barricade of waveguide 110
11 plate face out of plumb, also abbreviation waveguide 110 is obliquely arranged below.
Fig. 3 is the sectional view for the barricade 11 for splitting barricade 11 along the direction perpendicular with the plate face of barricade 11.
The axis A of waveguide 110 shown in figure and the plate face of barricade 11 form inclination angle δ.
The set-up mode vertical compared to the plate face of the axis of waveguide 110 and barricade 11, for the screen of same thickness
The waveguide 110 of shield plate 11, present embodiment being obliquely arranged has bigger axial dimension.In the present embodiment, incline
The axial dimension a for the waveguide 110 being tiltedly arranged is at least three times of the radial dimension r of waveguide 110.Preferably, inclination angle δ
Less than 45 degree, so that the thickness for the barricade 11 that the waveguide 110 for meeting shielding requirements is constituted is small as far as possible.
The benefit that waveguide 110 is obliquely arranged also resides in, and waveguide 110 has bigger surface area, this to shield
Cover 10 has better heat dissipation effect.This is because usually there is good heating conduction by metal waveguide 110, because
This, other than the thermal convection facilitated inside and outside progress shielding case 10 because waveguide 110 is hollow, waveguide 110 itself can pass through
Heat radiation effect is by the heat absorption in shielding case 10 and is dispersed into outside shielding case 10.
It should be appreciated that it is rectangular shape that waveguide 110, which is not limited to cross section, cross section is also possible to round, six sides
Shape or other shapes.In view of the shape of cross section can be a variety of and can be abnormity, in this case,
When calculating the radial dimension of waveguide 110, can approximatively on the cross section of waveguide 110 between any two points it is maximum away from
(side length of rectangle is defined as the waveguide 110 that cross section is rectangle shown in Fig. 3 from the radial dimension for being defined as waveguide 110
Radial dimension, be also a kind of approximate calculation method).
It should be appreciated that the cross section of multiple waveguides 110 on barricade 11 can be different shape, multiple waveguides
The inclined direction and tilt angle of 110 axis are also possible to inconsistent.
It is arranged with being closely close to it should be appreciated that may not be between multiple waveguides 110, adjacent waveguide 110 can
Not share tube wall.
It should be appreciated that shielding case 10 according to the present invention may not be rectangular shape, such as can be by multiple barricades
11 form pyramid or almost spherical etc..Barricade 11 may not be it is planar, but it is curved, when barricade 11 is in song
When face, the axis of waveguide 110 and the section of the barricade 11 where the waveguide 110 are obliquely arranged.
Next, introducing the printed circuit board assembly according to the present invention equipped with shielding case 10 with reference to Fig. 4 and Fig. 5.
The electric component group 21 for carrying out electromagnetic shielding processing is equipped on pcb board 20, in 21 housing of electric component group
If shielding case 10.In the present embodiment, shielding case 10 is connected to pcb board 20 by welding.The ground connection of shielding case 10 sets
It sets.
Since the pad 30 that scolding tin is constituted is conductive, shielding case 10 can be realized to be electrically connected with pcb board 20.
Preferably, pad 30 forms complete annular on pcb board 20, to prevent between shielding case 10 and pcb board 20
There is the gap of possible leakage electromagnetic wave.
It should be appreciated that the connection type of shielding case 10 and pcb board 20 is not limited to weld, the two can also be by having conduction
The material of property links together, for example, shielding case 10 and pcb board 20 are linked together by conducting resinl or conducting foam.
The part beneficial effect of above embodiment of the invention is briefly described below.
(i) multiple waveguides 110 are arranged together the webbed shielding case 10 of shape, shielding according to the present invention by the present invention
Cover 10 can realize the effect of electromagnetic shielding and heat dissipation simultaneously.
(ii) shielding case 10 and pcb board 20 are directly connected to by printed circuit board assembly according to the present invention, can prevent from shielding
It covers space and the gap of leakage electromagnetic wave occurs.10 one side of shielding case will be produced by the electric component group 21 as electromagnetic interference source
Blocking electromagnetic waves, i.e., prevent electromagnetic interference to propagate outward from source, efficiently and accurately reduce electric component group 21
To extraneous electromagnetic interference；On the other hand, extraneous electromagnetic interference shield can be made electric component group 21 not by outer by shielding case 10
The interference of boundary's electromagnetic wave and can work normally.
(iii) axis of waveguide 110 is obliquely arranged the present invention relative to the plate face of barricade 11, is not increasing screen
The axial length of waveguide 110 is increased under the premise of the thickness of shield plate 11, both ensure that the good shielding effect of shielding case 10
Fruit has saved space again.
(iii) shielding case 10 being made of waveguide 110 has good air permeability, volume can not be arranged for pcb board 20
Outer heat dissipation element.And shielding case 10 made of metal also has good thermal conductivity, the heat in shielding case 10 can shift
To shielding case 10 itself, it is dispersed into external environment again later.The waveguide 110 being obliquely installed further increases shielding case 10
Area, to more improve the heat dissipation effect of shielding case 10.Understand from the heat sinking function of the ground level of pcb board, shields
Cover 10 is seamlessly connect with the ground level of pcb board, the area equivalent to increase pcb board ground level；And consider shielding case 10
It is hollow out, and waveguide 110 is obliquely installed, the area of pcb board ground level is further increased, the heat dissipation of pcb board
Effect is good.
(iv) when pcb board 20 is applied to a certain product, traditional way is that shell is arranged for product, which both needed
Having waterproof and dampproof function, has the function of electromagnetic shielding again, this proposes very high requirement to the manufacture craft of shell,
Cost of manufacture is high.Using printed circuit board assembly according to the present invention, since the shielding case 10 of printed circuit board assembly has electricity
The function of magnetic screen, therefore the shell of product only needs general waterproof and dampproof function, the manufacture craft of shell is simple, makes
Make at low cost.
It should be appreciated that above embodiment is merely exemplary, it is not used in the limitation present invention.Those skilled in the art can be with
Various modifications and changes are made to above embodiment under the teachings of the present invention, without departing from the scope of the present invention.
Claims (10)
1. a kind of electro-magnetic shielding cover (10) is used for accommodating electric element to realize the effect of electromagnetic shielding, the shielding case
(10) it is made of an electrically conducting material, wherein
The cover of the shielding case (10) is hollow out, each hollow out position forms a waveguide (110), the waveguide
(110) axial dimension (a) is the three times of the radial dimension (r) of the waveguide (110) or more,
The axis (A) of the waveguide (110) is cut with the cover of the shielding case (10) at the waveguide (110) place
To out of plumb.
2. electro-magnetic shielding cover (10) according to claim 1, which is characterized in that the waveguide (110) of adjacent two
Share a tube wall.
3. electro-magnetic shielding cover (10) according to claim 1, which is characterized in that the shielding case (10) is by multiple barricades
(11) it is spliced to form.
4. electro-magnetic shielding cover (10) according to claim 3, which is characterized in that the axis (A) of the waveguide (110) with
The plate face of the barricade (11) forms inclination angle δ, and the inclination angle δ is less than 45 degree.
5. electro-magnetic shielding cover (10) according to claim 1, which is characterized in that the cross section of the waveguide (110) is in
Rectangle or hexagon or circle.
6. electro-magnetic shielding cover (10) according to claim 1, which is characterized in that the shielding case (10) is made of metal.
7. electro-magnetic shielding cover (10) according to claim 1, which is characterized in that the surface of the shielding case (10) is covered with
Conductive coating.
8. a kind of printed circuit board assembly, which is characterized in that it includes printed circuit board (20) and according to claim 1 in 7
Described in any item electro-magnetic shielding covers (10), shielding case (10) the ground connection setting,
The shielding case (10) links together with the printed circuit board (20), and the shielding case (10) will be installed on the print
The target electronic components of circuit board (20) processed are housed in the inner cavity of the shielding case (10).
9. printed circuit board assembly according to claim 8, which is characterized in that the shielding case (10) and printing electricity
Connector between road plate (20) forms annular.
10. printed circuit board assembly according to claim 9, which is characterized in that
The connector is the pad (30) being made of scolding tin, or
The connector is conducting resinl, or
The connector is conducting foam.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910093777.XA CN109688781A (en) | 2019-01-30 | 2019-01-30 | Electro-magnetic shielding cover and printed circuit board assembly |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910093777.XA CN109688781A (en) | 2019-01-30 | 2019-01-30 | Electro-magnetic shielding cover and printed circuit board assembly |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109688781A true CN109688781A (en) | 2019-04-26 |
Family
ID=66195265
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910093777.XA Pending CN109688781A (en) | 2019-01-30 | 2019-01-30 | Electro-magnetic shielding cover and printed circuit board assembly |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109688781A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112087938A (en) * | 2020-09-07 | 2020-12-15 | 深圳市智仁科技有限公司 | Method, circuit and system for resisting electromagnetic interference of computer mainboard |
| CN114025601A (en) * | 2021-11-15 | 2022-02-08 | 珠海格力电器股份有限公司 | Shielding device and electric appliance |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203691840U (en) * | 2013-12-07 | 2014-07-02 | 武汉南华工业设备工程股份有限公司 | Anti-electromagnetic heat radiation plate |
| CN206380252U (en) * | 2017-01-20 | 2017-08-04 | 河南农业职业学院 | Electronic device shields heat dissipating housing |
| US20180027705A1 (en) * | 2010-02-03 | 2018-01-25 | Djm Electronics, Inc. | Methods, devices, and systems for filtering electromagnetic interference |
-
2019
- 2019-01-30 CN CN201910093777.XA patent/CN109688781A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20180027705A1 (en) * | 2010-02-03 | 2018-01-25 | Djm Electronics, Inc. | Methods, devices, and systems for filtering electromagnetic interference |
| CN203691840U (en) * | 2013-12-07 | 2014-07-02 | 武汉南华工业设备工程股份有限公司 | Anti-electromagnetic heat radiation plate |
| CN206380252U (en) * | 2017-01-20 | 2017-08-04 | 河南农业职业学院 | Electronic device shields heat dissipating housing |
Non-Patent Citations (1)
| Title |
|---|
| 陈穷等: "《电磁兼容性工程设计手册》", 31 October 1993, 国防工业出版社 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112087938A (en) * | 2020-09-07 | 2020-12-15 | 深圳市智仁科技有限公司 | Method, circuit and system for resisting electromagnetic interference of computer mainboard |
| CN114025601A (en) * | 2021-11-15 | 2022-02-08 | 珠海格力电器股份有限公司 | Shielding device and electric appliance |
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| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
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| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20190426 |