# US 2001/0026440 A1 · EMI reduction device and assembly

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2001/0026440 A1
- Document ID: US20010026440A1
- Status: Published application
- Kind: A1
- Application number: 09/761,368
- Filed: 2001-01-16
- Published: 2001-10-04
- Earliest claimed: 1999-05-26
- Assignees: Hewlett-Packard Company
- Inventors: Hans T. Mellberg; Bertram Kim Cheong Chan; Susannah Gardner
- Web page: https://patentgrep.com/patent/US20010026440A1

## CPC

- H05K 7/1431: {Retention mechanisms for CPU modules}
- H05K 9/002: {with localised screening}
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 1)

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.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 1)

The apparatus of claim 1,
the EMI reduction device having a top surface and a bottom surface, the bottom surface having a dielectric layer.

### Claim 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.

### Claim 8 (depends on 7)

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.

### Claim 9 (depends on 7)

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.

### Claim 10 (depends on 7)

The apparatus of claim 7,
wherein the electronic device is a processor.

### Claim 11 (depends on 7)

The apparatus of claim 7,
wherein the bottom surface of the frame is non-electrically conductive.

### Claim 12 (depends on 7)

The apparatus of claim 7,
wherein the top surface of the frame is electrically conductive.

### Claim 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.

### Claim 14 (depends on 13)

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.

### Claim 15 (depends on 14)

The method of claim 14, comprising the step of:
attaching the frame to the thermal dissipation device.