US20010026440A1 - EMI reduction device and assembly - Google Patents

EMI reduction device and assembly Download PDF

Info

Publication number
US20010026440A1
US20010026440A1 US09/761,368 US76136801A US2001026440A1 US 20010026440 A1 US20010026440 A1 US 20010026440A1 US 76136801 A US76136801 A US 76136801A US 2001026440 A1 US2001026440 A1 US 2001026440A1
Authority
US
United States
Prior art keywords
electronic device
device
emi
circuit board
emi reduction
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.)
Granted
Application number
US09/761,368
Other versions
US6385048B2 (en
Inventor
Hans Mellberg
Bertram Cheong Chan
Susannah Gardner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hewlett Packard Development Co LP
Original Assignee
Mellberg Hans T.
Cheong Chan Bertram Kim
Susannah Gardner
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to US09/320,412 priority Critical patent/US6219239B1/en
Application filed by Mellberg Hans T., Cheong Chan Bertram Kim, Susannah Gardner filed Critical Mellberg Hans T.
Priority to US09/761,368 priority patent/US6385048B2/en
Publication of US20010026440A1 publication Critical patent/US20010026440A1/en
Application granted granted Critical
Publication of US6385048B2 publication Critical patent/US6385048B2/en
Assigned to HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P. reassignment HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HEWLETT-PACKARD COMPANY
Anticipated expiration legal-status Critical
Application status is Expired - Fee Related legal-status Critical

Links

Images

Classifications

    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K7/00Constructional details common to different types of electric apparatus
    • H05K7/14Mounting supporting structure in casing or on frame or rack
    • H05K7/1422Printed circuit boards receptacles, e.g. stacked structures, electronic circuit modules or box like frames
    • H05K7/1427Housings
    • H05K7/1429Housings for circuits carrying a CPU and adapted to receive expansion cards
    • H05K7/1431Retention mechanisms for CPU modules
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00Screening of apparatus or components against electric or magnetic fields
    • H05K9/0007Casings
    • H05K9/002Casings with localised screening

Abstract

An EMI reduction device coupled between to a printed circuit board (PCB) assembly and a heat sink is herein disclosed. The PCB assembly includes a processor core that is the source of unintentional electromagnetic interference (EMI). The EMI reduction device is attached to a heat sink which is positioned over the processor core such that it capacitively couples emissions from the processor core to a grounding plane resident in the PCB assembly, thereby reducing the unintentional EMI. Simultaneously, the EMI reduction device is able to maintain thermal contact with the heat sink.

Description

    FIELD OF THE INVENTION
  • The present invention relates generally to electronic systems. More particularly, the invention relates to an electromagnetic interference (EMI) reduction device. [0001]
  • BACKGROUND OF THE INVENTION
  • A trend in the electronics industry is to generate smaller and faster electronic devices. As a result, these devices consume more power and hence, produce more heat. Excessive heat can cause significant damage to an electronic device thereby reducing its life. For this reason, various techniques are employed to eliminate or dissipate the heat generated from the electronic device. A heat sink is one such technique. A heat sink is thermally coupled to the electronic device and as such, allows the heat to flow from the electronic device through the heat sink to the surrounding open space. [0002]
  • In addition, the operation of these electronic devices is accompanied by the generation of electromagnetic radiation or energy. The emissions of the electromagnetic radiation can cause significant electronic interference or noise with other surrounding electronic circuitry. To reduce such disturbances, the source of these emissions is usually suppressed. However, the EMI suppression problem is further complicated when the electronic device is coupled to a heat sink. The heat sink acts as an antenna for the EMI energy thereby amplifying the EMI energy. [0003]
  • A common solution for suppressing EMI energy is to ground the heat sink. FIG. 1 illustrates an exemplary grounded heat sink. There is shown a heat sink [0004] 100 coupled to a grounded electronic device 102 that is mounted onto a printed circuit board (PCB) 104. In this example, the grounded electronic device 102 is a processor core having a silicon logic die 106. A thermal compound 108, such as a dielectric material, is placed between the heat sink 100 and the grounded electronic device 102 so that thermal contact is maintained and the heat generated by the device 102 is transferred to the heat sink 100.
  • Mounting fences [0005] 110 are positioned on four opposite sides of the PCB 104 in order to ground the heat sink 100. The mounting fences 110 are attached to the heat sink 100 and the PCB 104, which acts in this case as a ground plane. The mounting fences 110 provide a Faraday shield around the device 102 in order to shield the EMI energy generated from the clock circuitry internal to the processor 102 from damaging adjacent components and from releasing EMI energy outside of the heat sink 100.
  • Additional EMI suppression is provided by four sets of grounding pads [0006] 112 a-112 d on the PCB 104 that surround the processor 102, as shown in FIG. 2. The grounding pads 112 minimize or ground EMI noise generated by the switching of all the component pins under maximum capacitive load. Thus, the combination of the grounding pads and the grounded heat sink dissipates the heat from the processor core and grounds the EMI energy generated by the processor core.
  • As the internal clock speed of processors increase, these processors will require more extensive EMI reduction or grounding. In some cases, the grounded heat sink approach may not be suitable to effectively eliminate the EMI emissions since this approach has a longer grounding path. As such, grounding may need to be performed closer to the silicon logic die in order to create a shorter grounding path that effectively shields the EMI energy emanating from the processor core. [0007]
  • Accordingly, there is a need for an EMI reduction technique that can minimize or eliminate EMI energy generated from a processor core closer to the source of the emissions and in such a manner that is cost efficient and easy to manufacture. [0008]
  • SUMMARY OF THE INVENTION
  • The present invention pertains to an EMI reduction device that is coupled between a printed circuit board (PCB) assembly and a heat sink. The PCB assembly includes a processor core that is the source of a large amount of electromagnetic interference. In a first embodiment, the EMI reduction device is fastened to a heat sink which is positioned over the processor core such that it capacitively couples the emissions from the processor while maintaining thermal contact with the heat sink. [0009]
  • In a first embodiment, the EMI reduction device has a electrically-conductive rectangular frame that includes a die aperture positioned in the center of the device, four mounting clip tabs, and four spring contact fingers. The die aperture allows the processor logic die to be in direct physical contact with the bottom surface of the heat sink thereby maintaining thermal contact between the processor logic die and the heat sink. The four mounting clip tabs are positioned on the outer periphery of the reduction device and are used to clip the EMI reduction device to the heat sink. [0010]
  • The spring contact fingers are located on each of the four sides of the processor. The spring contact fingers are the only portion of the EMI reduction device that maintains physical contact with the PCB assembly. This is to ensure that the EMI reduction device does not protrude directly onto the PCB assembly yet remains in close proximity to the processor. As such, the EMI reduction device is not in direct electrical contact with the PCB assembly. The EMI reduction device grounds the processor emissions by capacitively coupling them to the ground plane present in the PCB assembly. [0011]
  • A pair of heat sink retention clips is used to secure the heat sink to the PCB assembly. The heat sink retention clips are inserted through mounting holes on the heat sink in a downward direction through the mounting holes of the EMI clip and on the PCB assembly. [0012]
  • The placement of the EMI clip in close proximity with the processor is beneficial since it creates a shorter grounding path thereby effectively reducing the EMI energy emanating from the processor directly at the source. In addition, the EMI clip is able to accomplish this while maintaining thermal contact with the heat sink. Furthermore, performing the EMI reduction at the processor is more economical than incorporating an EMI reduction technique into a chassis assembly that houses the PCB assembly.[0013]
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • For a better understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which: [0014]
  • FIG. 1 is a schematic view of a prior art grounded heat sink assembly for a printed circuit board; [0015]
  • FIG. 2 is a top plan view of the printed circuit board used in the grounded heat sink assembly shown in FIG. 1; [0016]
  • FIG. 3 is a perspective view of a processor module in accordance with a first embodiment of the present invention; [0017]
  • FIG. 4 is an exploded view of the components of the processor module shown in FIG. 3; [0018]
  • FIG. 5 illustrates the processor module positioned on a printed circuit board as part of computer system in accordance with the embodiments of the present invention; [0019]
  • FIG. 6 is a front perspective view of the printed circuit board assembly shown in FIGS. 3 and 4; [0020]
  • FIG. 7 is a top plan view of the printed circuit board shown in FIG. 6; [0021]
  • FIG. 8 is a perspective view of the bottom side of the EMI clip shown in FIGS. 3 and 4; [0022]
  • FIG. 9 is a top plan view of the EMI clip positioned onto the printed circuit board assembly in accordance with a first embodiment of the present invention; [0023]
  • FIG. 10 is a perspective view of the heat sink shown in FIGS. 3 and 4 in accordance with the embodiments of the present invention; [0024]
  • FIG. 11 is cross-sectional view of the processor module taken along plane AA shown in FIG. 3; [0025]
  • FIG. 12 is a rear perspective view of the heat sink with the EMI clip attached thereto in accordance with the first embodiment of the present invention; [0026]
  • FIG. 13 is an isometric view of a printed circuit board having spring fingers mounted onto the PCB assembly in accordance with a second embodiment of the present invention; and [0027]
  • FIG. 14 is an isometric view of a printed circuit board having spring washers in accordance with a third embodiment of the present invention.[0028]
  • Like reference numerals refer to corresponding parts throughout the several views of the drawings. [0029]
  • DETAILED DESCRIPTION OF THE INVENTION
  • FIGS. 3 and 4 depict a processor module [0030] 120 having a PCB assembly 122, an EMI clip or reduction device 124, a heat sink 126, and a pair of heat sink retention clips 128 a-128 b. The PCB assembly 122 includes a processor core 130. The EMI clip 124 is positioned onto the PCB assembly 122 surrounding the processor core 130 and is used to efficiently shield the EMI emissions generated from the processor core 130. The EMI clip 124 is removably mounted to the heat sink 126. The heat sink 126 is thermally coupled to the PCB assembly 122 and is used to transfer the heat from the electronic components to the heat sink 126. A pair of heat sink retention clips 128 is used to fasten the heat sink 126 to the PCB assembly 122.
  • The processor module [0031] 120 can be removably mounted onto a motherboard or other type of circuit board. For example, as shown in FIG. 5, the processor module 120 is positioned onto a motherboard 127 through a processor retention assembly 129. The motherboard 127 can be part of a computer system, subsystem, or the like.
  • Preferably, the PCB assembly [0032] 122 is a Single Edge Contact Cartridge 2 (SECC2) manufactured by the Intel Corporation. The SECC2 supports “slot” type processors. A slot is a connector that is resident on a motherboard and which supports the Intel P6 microprocessor bus. Previously, microprocessors were mounted onto a motherboard through a socket. In a slot-type processor, the processor is placed on a PCB known as a single edge contact (SEC). The SEC has pins on an edge of the card which is inserted into a 242-pin slot on the motherboard . This pin construction is otherwise known as an edge finger connection.
  • A more detailed discussion of the SECC2 can be found in Intel Corporation, Single Edge Contact Connector 2 (S.E.C.C.2) Thermal Interface Material Functional Requirements, Order No: 244458-001, November 1998; Intel Corporation, Single Edge Contact Cartridge 2 (S.E.C.C.2) Heat Sink Attachment and Heat Sink Functional Requirements Order Number: 244456-001, Nov. 23, 1998; and Intel Corporation, S.E.C.C.2 Heat Sink Installation and Removal Process, Order Number 244454-001, December 1998 which are hereby incorporated by reference as background information. [0033]
  • FIG. 6 illustrates the SECC2 [0034] 122. There is shown a printed circuit board 132 and a cover 134. The PCB 132 is preferably a substrate constructed of a multilayer plastic laminate, such as a plastic land grid array or organic land grid array processor core substrates. The substrate 132 has an edge finger connection. In addition, the substrate 132 includes a ground plane. The cover 134 is used to protect the PCB 132 and is removably mounted to the cover 134 through a set of snaps 136. However, it should be noted that the technology of the present invention is not constrained to the SECC2, to any particular circuit board, or to any particular circuit board layout.
  • FIG. 7 illustrates the PCB [0035] 132 in further detail. There is a processor core 130 that includes a silicon logic die 138. The PCB 132 includes four attachment holes 140 a-140 d through which the heat sink retention clips 128 are fit so that the heat sink can be attached to the PCB assembly 122. In addition, surrounding the logic die 138, there are other electronic components, such as but not limited to cache memory, resistors, capacitors, and the like. However, in this embodiment of the PCB 132, there are no grounding pads.
  • FIG. 8 illustrates the EMI clip [0036] 124. The EMI clip 124 has rectangular-shaped frame including a die aperture 150, four mounting clip tabs 152 a-152 d, four attachment holes 154 a-154 d, and four spring contact fingers 156 a-156 d. The die aperture 150 is of a rectangular shape and is located in the center of the EMI clip 124. The EMI clip 124 is positioned over the logic die 138 so that the die aperture 150 allows the logic die 138 to be in direct physical contact with the surface of the heat sink 126.
  • The four mounting clip tabs [0037] 152 a-152 d are used to attach the EMI clip 124 to the heat sink 126. The mounting clip tabs 152 a-152 d are located on the outer periphery of the EMI clip 124 and are situated in each corner of the top side of the EMI clip 124.
  • The mounting holes [0038] 154 a-154 d are located on the surface of the top side of the EMI clip 124 and each mounting hole 154 is located at a particular corner of the EMI clip 124. Each of the four mounting holes 154 a-154 d are aligned with a respective mounting hole 140 on the PCB 132 and with a respective mounting hole on the heat sink. The retention clips 128 are inserted through the mounting holes 166 on the heat sink 126 in a downward direction through the mounting holes 154 on the EMI clip 124 through the mounting holes 140 on the PCB 132.
  • The four spring contact fingers [0039] 156 a-156 d are situated on the bottom side of the EMI clip 124 and allow the EMI clip 124 to maintain physical contact on four sides of the processor core 130. The contact fingers 156 are the only portion of the EMI clip 124 that is in physical contact with the PCB 132. The spring fingers 156 ensure that the frame of the EMI clip 124 does not protrude directly onto any of the components of the PCB 132. Direct contact with the processor substrate 132 would damage the electronic components positioned under the EMI clip 124. As such, each of the spring contact fingers 156 is positioned on the PCB 132 in an area where there are no electronic components.
  • The shape, size and dimension of the EMI clip [0040] 124 is tailored for the particular processor substrate 132 to which the clip 124 is coupled. FIG. 9 illustrates the placement of the EMI clip 124 onto a SECC2 122. For this embodiment, the EMI clip 124 is approximately 48.97 mm by 54.35 mm. The die aperture 150 is 19 mm by 18 mm and is constructed such that there is a 6 mm distance between the outer edge of the processor aperture to the outer edge of the processor logic die. It should be noted that the present invention is not constrained to an EMI clip 124 having the particular shape, size and dimensions described herein and one skilled in the art can easily modify the design of the EMI clip 124 to suit other PCBs or the like.
  • The electromagnetic bandwidth of the processor core can extend to include multiple times the advertised processor clock speed. In the case of an Intel Pentium II processor with an internal clock speed of 500 MHz, the EMI bandwidth can extend to 2500 MHz or more. The EMI clip [0041] 124 reduces portions of that bandwidth with varying shielding effectiveness and can vary depending on the mechanical dimensions of the EMI clip 124. Another modifier to EMI reduction is the mechanical pressure that exits both on the heat sink 126 and on the processor core 130. The higher the pressure the more effective the capacitive coupling becomes and hence the EMI reduction.
  • Preferably, the EMI clip [0042] 124 is constructed of thin steel sheet metal. However, the present invention is not constrained to any particular type of metal and can be constructed of any material, such as but not limited to stainless steel, beryllium copper, phospher bronze, hardened steel, spring steel, and the like.
  • Referring to FIG. 12, the bottom side of the heat sink [0043] 126, that side which touches the PCB 132, is coated with a dielectric layer that ensures that the EMI clip 124 does not short the electronic components mounted on the surface of the PCB 132. An example of such a dielectric coating is powder paint, in particular, the epoxy power coatings based on epoxy resins.
  • The placement of the EMI clip [0044] 124 over the processor core 130 and in the manner described above is effective in reducing the EMI emissions from the processor core 130. Although, the EMI clip 124 is not in direct electrical contact with the processor core 130, its close proximity to the processor core 130 capacitively couples these emissions to the ground plane of the substrate 132 and through a shorter grounding path. As a result, the emissions are minimized or eliminated directly at the processor core 130.
  • FIGS. 10 and 11 illustrates the heat sink [0045] 126. The heat sink 126 has a number of fins 160, a base portion 162, and two skirts 164 a-164 b. The fins 160 project outwardly and upwardly from the base portion 162. The base portion 162 extends over and covers the processor core 130 thereby providing the maximum amount of thermal contact area between the processor core 130 and the heat sink 126. The two skirts 164 a-164 b extend laterally and downwardly from the base portion 162 and extends over and covers opposite sides of the PCB assembly 122.
  • The fins [0046] 160 are eliminated where the heat sink retention clips 128 are positioned (see FIGS. 3 and 4) into two groves situated on the top surface of the base portion of the heat sink 126. The groves include mounting holes 166 that enable the heat sink retention clips 128 to fit through the top surface of the base portion 162. The retention clips 128 are inserted through the mounting holes 166 on the heat sink 126 in a downward direction through the mounting holes 154 on the EMI clip 124 through the mounting holes 140 on the PCB 132.
  • The heat sink retention clips [0047] 128 are made from a flexible material that is non-electrically conductive, such as plastic. The heat sink retention clips 128 are secured at one end in any appropriate manner, and in the present example by barbed ties. Preferably, the heat sink retention clips 128 are those heat sink retention clips designed for the SECC2 and which are manufactured by ITW Fastex.
  • FIG. 12 illustrates the bottom side of the base portion [0048] 162 of the heat sink 126. There is shown the EMI clip 124 mounted to the base portion 162 of the heat sink 126. Each mounting clip 152 is fitted over onto a corresponding groove 170 on the base portion of the heat sink 126.
  • The heat sink [0049] 126 is made of aluminum that is chromate conversion coated and is electrically conductive. A thermal compound 168, such as a dielectric layer, is placed on the bottom side of the base portion 162 of the heat sink 126. This dielectric layer is used to provide high dielectric capacity and to provide a high thermal conductivity between the processor logic die 138 and the heat sink 126. An example of such a compound is MCM-STRATE® manufactured by Power Devices, Inc. However, the present invention is not constrained to any particular type of material and other materials having the same properties can also be used.
  • The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. In other instances, well known circuits and devices are shown in order to avoid unnecessary distraction from the underlying invention. Thus, the foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents. [0050]
  • In particular, one skilled in the art can alter the EMI clip described above to include additional spring fingers in order to provide more capacitive contacts between the EMI clip and the substrate. In another alternate embodiment, the EMI clip can be used in conjunction with grounding pads that are positioned on the substrate. In yet another embodiment, the EMI clip can be made an integral part of the heat sink and not a separate device. Furthermore, the EMI clip can be made without the dielectric coating on the bottom surface thereby making electrical contact with the PCB. Alternatively, the EMI clip can be applied to a processor that is mounted directly onto a motherboard and is not constrained to edge finger connection devices. [0051]
  • FIG. 13 illustrates a second embodiment of the present invention. In this embodiment, there is no EMI clip [0052] 124 rather spring fingers 180 a-180 d mounted directly onto the printed circuit board 132′. Preferably, a spring finger 180 is mounted on each side surrounding the processor core 130′. As shown in FIG. 13, there are four spring fingers 180 a-180 d mounted directly onto the circuit board 132′. However, the number of spring fingers 180 and their position of the circuit board 132 is not a limitation of this embodiment.
  • A heat sink is mounted directly over the circuit board [0053] 132′ and coupled with retention clips in the manner described above. The bottom surface of the heat sink will be in direct physical contact with the processor die 138′ and the top surface of the spring fingers 180. As such, the emissions from the processor die 138′ are capacitively coupled to the ground plane in the circuit board 132′ and suppressed directly at the source of the emissions.
  • FIG. 14 illustrates a third embodiment of the present invention. In this embodiment, the ground plane of the circuit board [0054] 132″ is extended to and through the mounting holes 140 a″-140 d″ on the circuit board 132″. A spring washer 182 a-182 d is mounted in each mounting hole 140 a″-140 d″. A heat sink is mounted over the top surface of the circuit board 132″.
  • The spring washers [0055] 182 are formed of an electrically conductive material, such as but not limited to thin sheet steel metal and are shaped as a compression coil. The spring washers 182 serve to ground the emissions from the processor core 130″ while ensuring that the placement of the heat sink on top of the circuit board 132″ does not damage the processor core 130″ and the electronic components mounted thereon.
  • Each spring washer [0056] 182 has a hollow core that is wide enough to allow a retention clip to fit through it thereby allowing the heat sink to be fastened to the circuit board 132″ in the manner described above. When the heat sink is fastened to the circuit board 132″, the spring washers 182 are compressed by the weight of the heat sink and the bottom surface of the heat sink is in direct physical contact with the processor die 138″ and the top surface of the spring washers 182. As such, the emissions from the processor die 138″ are grounded to the ground plane in the circuit board 132″ and suppressed directly at the source of the emissions.

Claims (15)

In the claims:
1. An electronic assembly apparatus, comprising:
a circuit board having a top surface and a bottom surface, the circuit board including an electronic device emanating electromagnetic emissions;
an EMI reduction device that is coupled to the circuit board, the EMI reduction device is positioned around the outer periphery of the electronic device, the EMI reduction device touches the circuit board at contact points that surround the electronic device, the EMI reduction device has no physical contact with the electronic device; and
a thermal dissipation device that is coupled to the EMI reduction device and the circuit board, the thermal dissipation device is positioned over the top surface of the circuit board;
wherein the thermal dissipation device dissipates heat generated from the circuit board;
wherein the EMI reduction device reduces electromagnetic emissions generated from the electronic device.
2. The apparatus of
claim 1
,
the EMI reduction device including at least one mounting clip for attaching the EMI reduction device to the thermal dissipation device.
3. The apparatus of
claim 1
,
the EMI reduction device including a plurality of spring fingers that surround the electronic device and maintain physical contact with the circuit board.
4. The apparatus of
claim 1
,
the EMI reduction device including an aperture that is positioned over the electronic device;
wherein the aperture enables the electronic device to maintain thermal contact with the thermal dissipation device.
5. The apparatus of
claim 1
,
the thermal dissipation device having a top surface and a bottom surface, the bottom surface including a thermal compound;
wherein the thermal compound is coupled to the electronic device.
6. The apparatus of
claim 1
,
the EMI reduction device having a top surface and a bottom surface, the bottom surface having a dielectric layer.
7. An EMI reduction device for use with an electronic device mounted on a circuit board, comprising:
a frame that is coupled to the circuit board, the frame surrounds peripheral portions of the electronic device, the frame is not in physical contact with the electronic device, the frame having a top surface and a bottom surface; and
a plurality of spring fingers that are coupled to the circuit board, the spring fingers are positioned onto the circuit board at points that surround the electronic device.
8. The apparatus of
claim 7
, comprising:
an aperture that surrounds the electronic device;
wherein the aperture enables the electronic device to maintain thermal contact with a thermal dissipation device.
9. The apparatus of
claim 7
, comprising:
a fastener that is coupled to a thermal dissipation device;
wherein the fastener enables the EMI reduction device to be detachably mounted to a thermal dissipation device.
10. The apparatus of
claim 7
,
wherein the electronic device is a processor.
11. The apparatus of
claim 7
,
wherein the bottom surface of the frame is non-electrically conductive.
12. The apparatus of
claim 7
,
wherein the top surface of the frame is electrically conductive.
13. A method for reducing EMI emissions emanating from an electronic device having a ground plane, said method comprising the steps of:
surrounding the outer periphery of the electronic device with a frame that has no direct physical contact with the electronic device;
contacting the frame to the ground plane at contact points that surround the electronic device; and
capacitively coupling the EMI emissions from the electronic device to the ground plane.
14. The method of
claim 13
, comprising the steps of:
placing a thermal dissipation device over the electronic device; and
dissipating heat generated from the electronic device through the thermal dissipation device.
15. The method of
claim 14
, comprising the step of:
attaching the frame to the thermal dissipation device.
US09/761,368 1999-05-26 2001-01-16 EMI reduction device and assembly Expired - Fee Related US6385048B2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US09/320,412 US6219239B1 (en) 1999-05-26 1999-05-26 EMI reduction device and assembly
US09/761,368 US6385048B2 (en) 1999-05-26 2001-01-16 EMI reduction device and assembly

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US09/761,368 US6385048B2 (en) 1999-05-26 2001-01-16 EMI reduction device and assembly

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US09/320,412 Continuation US6219239B1 (en) 1999-05-26 1999-05-26 EMI reduction device and assembly

Publications (2)

Publication Number Publication Date
US20010026440A1 true US20010026440A1 (en) 2001-10-04
US6385048B2 US6385048B2 (en) 2002-05-07

Family

ID=23246312

Family Applications (2)

Application Number Title Priority Date Filing Date
US09/320,412 Expired - Lifetime US6219239B1 (en) 1999-05-26 1999-05-26 EMI reduction device and assembly
US09/761,368 Expired - Fee Related US6385048B2 (en) 1999-05-26 2001-01-16 EMI reduction device and assembly

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US09/320,412 Expired - Lifetime US6219239B1 (en) 1999-05-26 1999-05-26 EMI reduction device and assembly

Country Status (1)

Country Link
US (2) US6219239B1 (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030151906A1 (en) * 2000-11-21 2003-08-14 Schaffer Michael J. Electromagnetic noise suppression device
US20100091462A1 (en) * 2007-02-15 2010-04-15 Nec Corporation Electronic device-mounted apparatus and noise suppression method for same
US20130294092A1 (en) * 2012-04-13 2013-11-07 Cree, Inc. Led lamp
US9651240B2 (en) 2013-11-14 2017-05-16 Cree, Inc. LED lamp
US20170251549A1 (en) * 2014-10-17 2017-08-31 3M Innovative Properties Company Electronic circuit board assembly including emi shielding structure and thermal pad
WO2017176521A1 (en) * 2016-04-04 2017-10-12 Commscope Technologies Llc Systems and methods for thermal management for high power density emi shielded electronic devices
US9810379B2 (en) 2012-04-13 2017-11-07 Cree, Inc. LED lamp
US9951909B2 (en) 2012-04-13 2018-04-24 Cree, Inc. LED lamp

Families Citing this family (97)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7049761B2 (en) 2000-02-11 2006-05-23 Altair Engineering, Inc. Light tube and power supply circuit
AT361656T (en) * 2000-03-03 2007-05-15 Sony Computer Entertainment Inc Electrical equipment and shade
US6346672B1 (en) * 2000-07-03 2002-02-12 Chin Fu Horng Structure for preventing electromagnetic interference of central processing unit
US6501655B1 (en) * 2000-11-20 2002-12-31 Intel Corporation High performance fin configuration for air cooled heat sinks
MXPA03004441A (en) * 2000-11-20 2005-01-25 Intel Corp High performance heat sink configurations for use in high density packaging applications.
US6633484B1 (en) 2000-11-20 2003-10-14 Intel Corporation Heat-dissipating devices, systems, and methods with small footprint
US6396697B1 (en) * 2000-12-07 2002-05-28 Foxconn Precision Components Co., Ltd. Heat dissipation assembly
US6501018B2 (en) * 2001-01-31 2002-12-31 Hewlett-Packard Company EMI gasket having enhanced z-axis compliance
US6479895B1 (en) 2001-05-18 2002-11-12 Intel Corporation High performance air cooled heat sinks used in high density packaging applications
US6803652B2 (en) * 2001-05-30 2004-10-12 Intel Corporation Heat dissipation device having a load centering mechanism
DE10129788B4 (en) * 2001-06-20 2005-11-10 Siemens Ag Plastic frame for mounting an electronic power control unit
US6477058B1 (en) 2001-06-28 2002-11-05 Hewlett-Packard Company Integrated circuit device package including multiple stacked components
TW511450B (en) * 2001-08-16 2002-11-21 Orient Semiconductor Elect Ltd Heat dissipation plate with inlay pin and its assembly components
US6705144B2 (en) 2001-09-10 2004-03-16 Intel Corporation Manufacturing process for a radial fin heat sink
US6671172B2 (en) * 2001-09-10 2003-12-30 Intel Corporation Electronic assemblies with high capacity curved fin heat sinks
US6831844B1 (en) * 2001-11-13 2004-12-14 Nortel Networks Limited Electronic circuit unit providing EMI shielding
JP3094311U (en) * 2001-12-28 2003-06-13 榮益科技有限公司 Flat spring used for connection to the circuit board
US6683796B2 (en) 2002-01-09 2004-01-27 Sun Microsystems, Inc. Apparatus for containing electromagnetic interference
US6661663B1 (en) 2002-02-05 2003-12-09 Calix Networks, Inc. Fiber guide connected to a heatsink fastener
US6728103B1 (en) * 2002-02-05 2004-04-27 Calix Networks, Inc. Heat sink with a cutout
US6618271B1 (en) 2002-04-01 2003-09-09 Gateway, Inc. EMI shield
US6747870B2 (en) 2002-04-25 2004-06-08 Gateway, Inc. Electromagnetic interference reduction air duct
US6639800B1 (en) 2002-04-30 2003-10-28 Advanced Micro Devices, Inc. Heat sink subassembly
US20030227759A1 (en) * 2002-06-10 2003-12-11 Haworth Stephen Paul Electromagnetic interference gasket
US6698060B1 (en) * 2002-06-10 2004-03-02 Hando Industrial Co., Ltd. Caster structure
GB2389710B (en) * 2002-06-10 2006-02-08 Sun Microsystems Inc Electronics module
US6944025B2 (en) * 2002-08-20 2005-09-13 Sun Microsystems, Inc. EMI shielding apparatus
US7115817B2 (en) * 2002-09-18 2006-10-03 Sun Microsystems, Inc. Heat sink and electromagnetic interference reduction device
TW549530U (en) * 2002-11-29 2003-08-21 Hon Hai Prec Ind Co Ltd Case for portable storage peripheral
US6943436B2 (en) * 2003-01-15 2005-09-13 Sun Microsystems, Inc. EMI heatspreader/lid for integrated circuit packages
US6992894B1 (en) * 2003-03-17 2006-01-31 Unisys Corporation Method and apparatus for EMI shielding
US7480143B2 (en) * 2003-04-21 2009-01-20 Hewlett-Packard Development Company, L.P. Variable-gap thermal-interface device
US6798663B1 (en) * 2003-04-21 2004-09-28 Hewlett Packard Development Company, L.P. Heat sink hold-down with fan-module attach location
US20040226688A1 (en) * 2003-04-30 2004-11-18 Arthur Fong Application specific apparatus for dissipating heat from multiple electronic components
US6872880B2 (en) 2003-06-17 2005-03-29 Delphi Technologies, Inc. Two-piece solderless EMC/EMI shield
US7035107B2 (en) * 2003-07-11 2006-04-25 Intel Corporation High serviceability heatsink retainer method and apparatus
US7151669B2 (en) * 2003-07-18 2006-12-19 Kechuan K Liu Configurable heat sink with matrix clipping system
KR100522696B1 (en) 2003-09-20 2005-10-19 삼성에스디아이 주식회사 Filter holder and display apparatus comprising the same
US7186924B2 (en) * 2003-10-21 2007-03-06 International Business Machines Corporation Dielectric structure for printed circuit board traces
US6909043B1 (en) 2003-11-12 2005-06-21 Sun Microsystems, Inc. EMI seal for system chassis
US6950310B2 (en) * 2003-12-31 2005-09-27 Texas Instruments Incorporated System and method for self-leveling heat sink for multiple height devices
US7164587B1 (en) 2004-01-14 2007-01-16 Sun Microsystems, Inc. Integral heatsink grounding arrangement
US7239507B1 (en) 2004-03-24 2007-07-03 Sun Microsystems, Inc. Slot frame with guide tabs for reducing EMI gaps
US7239516B2 (en) * 2004-09-10 2007-07-03 International Business Machines Corporation Flexure plate for maintaining contact between a cooling plate/heat sink and a microchip
US7212408B2 (en) * 2004-12-28 2007-05-01 Intel Corporation Multi-slot socket for mounting integrated circuits on circuit board
US7321492B2 (en) * 2005-02-15 2008-01-22 Inventec Corporation Heat sink module for an electronic device
US7327577B2 (en) * 2005-11-03 2008-02-05 International Business Machines Corporation Method and apparatus for grounding a heat sink in thermal contact with an electronic component using a grounding spring having multiple-jointed spring fingers
US7355857B2 (en) * 2006-02-07 2008-04-08 Methode Electronics, Inc. Heat sink gasket
US8169789B1 (en) * 2007-04-10 2012-05-01 Nvidia Corporation Graphics processing unit stiffening frame
TWM332216U (en) * 2007-10-09 2008-05-11 Wistron Corp Auxiliary mechanism
US8118447B2 (en) 2007-12-20 2012-02-21 Altair Engineering, Inc. LED lighting apparatus with swivel connection
US7712918B2 (en) 2007-12-21 2010-05-11 Altair Engineering , Inc. Light distribution using a light emitting diode assembly
US8360599B2 (en) 2008-05-23 2013-01-29 Ilumisys, Inc. Electric shock resistant L.E.D. based light
US7976196B2 (en) 2008-07-09 2011-07-12 Altair Engineering, Inc. Method of forming LED-based light and resulting LED-based light
US7946729B2 (en) 2008-07-31 2011-05-24 Altair Engineering, Inc. Fluorescent tube replacement having longitudinally oriented LEDs
US8674626B2 (en) 2008-09-02 2014-03-18 Ilumisys, Inc. LED lamp failure alerting system
US8256924B2 (en) 2008-09-15 2012-09-04 Ilumisys, Inc. LED-based light having rapidly oscillating LEDs
US8901823B2 (en) 2008-10-24 2014-12-02 Ilumisys, Inc. Light and light sensor
US8444292B2 (en) 2008-10-24 2013-05-21 Ilumisys, Inc. End cap substitute for LED-based tube replacement light
US8324817B2 (en) 2008-10-24 2012-12-04 Ilumisys, Inc. Light and light sensor
US7938562B2 (en) 2008-10-24 2011-05-10 Altair Engineering, Inc. Lighting including integral communication apparatus
US8653984B2 (en) 2008-10-24 2014-02-18 Ilumisys, Inc. Integration of LED lighting control with emergency notification systems
US8214084B2 (en) 2008-10-24 2012-07-03 Ilumisys, Inc. Integration of LED lighting with building controls
US8556452B2 (en) 2009-01-15 2013-10-15 Ilumisys, Inc. LED lens
US8362710B2 (en) 2009-01-21 2013-01-29 Ilumisys, Inc. Direct AC-to-DC converter for passive component minimization and universal operation of LED arrays
US8664880B2 (en) 2009-01-21 2014-03-04 Ilumisys, Inc. Ballast/line detection circuit for fluorescent replacement lamps
US8330381B2 (en) 2009-05-14 2012-12-11 Ilumisys, Inc. Electronic circuit for DC conversion of fluorescent lighting ballast
CN101902892A (en) * 2009-05-26 2010-12-01 鸿富锦精密工业(深圳)有限公司;鸿海精密工业股份有限公司 Heat radiator fixing device
US8299695B2 (en) 2009-06-02 2012-10-30 Ilumisys, Inc. Screw-in LED bulb comprising a base having outwardly projecting nodes
US8421366B2 (en) 2009-06-23 2013-04-16 Ilumisys, Inc. Illumination device including LEDs and a switching power control system
CA2794512A1 (en) 2010-03-26 2011-09-29 David L. Simon Led light tube with dual sided light distribution
CA2794541C (en) 2010-03-26 2018-05-01 David L. Simon Inside-out led bulb
CA2792940A1 (en) * 2010-03-26 2011-09-19 Ilumisys, Inc. Led light with thermoelectric generator
US8454193B2 (en) 2010-07-08 2013-06-04 Ilumisys, Inc. Independent modules for LED fluorescent light tube replacement
JP2013531350A (en) 2010-07-12 2013-08-01 イルミシス,インコーポレイテッドiLumisys,Inc. Circuit board mount for LED arc tube
EP2633227B1 (en) 2010-10-29 2018-08-29 iLumisys, Inc. Mechanisms for reducing risk of shock during installation of light tube
US8870415B2 (en) 2010-12-09 2014-10-28 Ilumisys, Inc. LED fluorescent tube replacement light with reduced shock hazard
CN102740665A (en) * 2011-04-08 2012-10-17 鸿富锦精密工业(深圳)有限公司 Anti-electromagnetic interference elastic sheet and electronic apparatus adopting same
US9072171B2 (en) 2011-08-24 2015-06-30 Ilumisys, Inc. Circuit board mount for LED light
WO2013131002A1 (en) 2012-03-02 2013-09-06 Ilumisys, Inc. Electrical connector header for an led-based light
WO2014008463A1 (en) 2012-07-06 2014-01-09 Ilumisys, Inc. Power supply assembly for led-based light tube
US9271367B2 (en) 2012-07-09 2016-02-23 Ilumisys, Inc. System and method for controlling operation of an LED-based light
US9285084B2 (en) 2013-03-14 2016-03-15 Ilumisys, Inc. Diffusers for LED-based lights
US9538693B2 (en) * 2013-03-15 2017-01-03 A.K. Stamping Company, Inc. Aluminum EMI / RF shield
US9047060B2 (en) * 2013-08-16 2015-06-02 Adlink Technology Inc. Heating element and circuit module stack structure
US9267650B2 (en) 2013-10-09 2016-02-23 Ilumisys, Inc. Lens for an LED-based light
KR20160093744A (en) * 2013-12-06 2016-08-09 마르세시 메탈 테크놀로지 (수조우) 컴퍼니 리미티드 A heat dissipating enclosure with integrated cooling fins
KR20160111975A (en) 2014-01-22 2016-09-27 일루미시스, 인크. Led-based light with addressed leds
US10104758B2 (en) * 2014-02-21 2018-10-16 Ati Technologies Ulc Heat sink with configurable grounding
EP3120673B1 (en) * 2014-03-21 2018-04-18 Robert Bosch GmbH Common mode noise suppression of switch-mode power converters by capacitive shield with damping network
EP2933833A1 (en) * 2014-04-16 2015-10-21 Thomson Licensing Electromagnetic shielding device
US9510400B2 (en) 2014-05-13 2016-11-29 Ilumisys, Inc. User input systems for an LED-based light
CN105849897B (en) * 2014-10-17 2019-09-27 华为技术有限公司 Radiate shielding construction and communication products
US10161568B2 (en) 2015-06-01 2018-12-25 Ilumisys, Inc. LED-based light with canted outer walls
US20170347490A1 (en) * 2016-05-24 2017-11-30 Texas Instruments Incorporated High-frequency antenna structure with high thermal conductivity and high surface area
US10236232B2 (en) 2017-01-19 2019-03-19 Advanced Micro Devices, Inc. Dual-use thermal management device
US10237965B2 (en) * 2017-02-23 2019-03-19 iS5 Communications Inc. Symmetrical and orthogonal component design

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5136120A (en) 1989-12-20 1992-08-04 At&T Bell Laboratories Technique for reducing electromagnetic interference
US5053924A (en) * 1990-03-30 1991-10-01 Motorola, Inc. Electromagnetic shield for electrical circuit
US5278351A (en) 1991-04-02 1994-01-11 Zeos International, Inc. Personal computer cabinet cover with EMI clips
CA2114325C (en) 1991-08-09 1997-01-28 Randall J. Diaz Electronic assembly with improved grounding and emi shielding
US5357404A (en) 1991-11-18 1994-10-18 The Whitaker Corporation EMI shield, and assembly using same
US5241453A (en) * 1991-11-18 1993-08-31 The Whitaker Corporation EMI shielding device
US5428508A (en) * 1994-04-29 1995-06-27 Motorola, Inc. Method for providing electromagnetic shielding of an electrical circuit
US5566052A (en) * 1995-06-08 1996-10-15 Northern Telecom Limited Electronic devices with electromagnetic radiation interference shields and heat sinks
US5740013A (en) * 1996-07-03 1998-04-14 Hewlett-Packard Company Electronic device enclosure having electromagnetic energy containment and heat removal characteristics
US5880930A (en) 1997-06-18 1999-03-09 Silicon Graphics, Inc. Electromagnetic interference shielding enclosure and heat sink with compression coupling mechanism
US6053771A (en) * 1997-08-20 2000-04-25 Dell Usa L.P. Electromagnetic shield connector
US6043983A (en) * 1998-06-17 2000-03-28 Intel Corporation EMI containment for microprocessor core mounted on a card using surface mounted clips
US6188577B1 (en) * 1999-11-18 2001-02-13 Yen-Wen Liu Protective device for central processing unit
US6205026B1 (en) * 2000-01-31 2001-03-20 Intel Corporation Heat sink retention components and system

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030151906A1 (en) * 2000-11-21 2003-08-14 Schaffer Michael J. Electromagnetic noise suppression device
US6819572B2 (en) * 2000-11-21 2004-11-16 Intel Corporation Electromagnetic noise suppression device
US20100091462A1 (en) * 2007-02-15 2010-04-15 Nec Corporation Electronic device-mounted apparatus and noise suppression method for same
US20130294092A1 (en) * 2012-04-13 2013-11-07 Cree, Inc. Led lamp
US9395074B2 (en) * 2012-04-13 2016-07-19 Cree, Inc. LED lamp with LED assembly on a heat sink tower
US9810379B2 (en) 2012-04-13 2017-11-07 Cree, Inc. LED lamp
US9951909B2 (en) 2012-04-13 2018-04-24 Cree, Inc. LED lamp
US9651240B2 (en) 2013-11-14 2017-05-16 Cree, Inc. LED lamp
US20170251549A1 (en) * 2014-10-17 2017-08-31 3M Innovative Properties Company Electronic circuit board assembly including emi shielding structure and thermal pad
US10104763B2 (en) * 2014-10-17 2018-10-16 3M Innovative Properties Company Electronic circuit board assembly including EMI shielding structure and thermal pad
WO2017176521A1 (en) * 2016-04-04 2017-10-12 Commscope Technologies Llc Systems and methods for thermal management for high power density emi shielded electronic devices

Also Published As

Publication number Publication date
US6219239B1 (en) 2001-04-17
US6385048B2 (en) 2002-05-07

Similar Documents

Publication Publication Date Title
US5390078A (en) Apparatus for using an active circuit board as a heat sink
US7327577B2 (en) Method and apparatus for grounding a heat sink in thermal contact with an electronic component using a grounding spring having multiple-jointed spring fingers
US5166864A (en) Protected circuit card assembly and process
US5500789A (en) Printed circuit board EMI shielding apparatus and associated methods
CN1264256C (en) Integrated circuit receptacle with integrated shield component
US5586011A (en) Side plated electromagnetic interference shield strip for a printed circuit board
US5653596A (en) Grounding system for PC cards
JP4469563B2 (en) Electronic equipment, electromagnetic wave radiation suppression member
US6930891B1 (en) Electromagnetic shielding plate, electromagnetic shielding structure, and entertainment system
US6577504B1 (en) Integrated heat sink for different size components with EMI suppression features
US7692927B2 (en) Shielding and heat dissipation device
EP0682322B1 (en) An IC card
US8929078B2 (en) Electronic control device
US7235880B2 (en) IC package with power and signal lines on opposing sides
US6958732B2 (en) Small-sized and high-gained antenna-integrated module
US6310773B1 (en) Heat sink system
US5726864A (en) Cage system
EP1493314B1 (en) Board-level emi shield with enhanced thermal dissipation
US6734045B2 (en) Lossy RF shield for integrated circuits
JP3294785B2 (en) Heat radiation structure of the circuit elements
US6670559B2 (en) Electromagnetic shield for printed circuit boards
US6515870B1 (en) Package integrated faraday cage to reduce electromagnetic emissions from an integrated circuit
US6456504B1 (en) Surface mounted grounding clip for shielded enclosures
US6800805B2 (en) Noise suppressing structure for shielded cable
US6683796B2 (en) Apparatus for containing electromagnetic interference

Legal Events

Date Code Title Description
CC Certificate of correction
FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

AS Assignment

Owner name: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P., TEXAS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HEWLETT-PACKARD COMPANY;REEL/FRAME:026945/0699

Effective date: 20030131

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Expired due to failure to pay maintenance fee

Effective date: 20140507