EP0883978A1 - Shielding device for ventilation panels of electronic instruments and method for manufacture thereof - Google Patents
Shielding device for ventilation panels of electronic instruments and method for manufacture thereofInfo
- Publication number
- EP0883978A1 EP0883978A1 EP97906734A EP97906734A EP0883978A1 EP 0883978 A1 EP0883978 A1 EP 0883978A1 EP 97906734 A EP97906734 A EP 97906734A EP 97906734 A EP97906734 A EP 97906734A EP 0883978 A1 EP0883978 A1 EP 0883978A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- honeycomb
- shielding device
- electromagnetic shielding
- frame
- recited
- 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.)
- Withdrawn
Links
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
- H05K9/0041—Ventilation panels having provisions for screening
Definitions
- Braised or welded honeycombs must be made from brass or steel and are expensive to manufacture.
- Glued honeycombs may be made of the less expensive aluminum strips, but the glue in prior art is insulating and provides sufficient conductivity in one direction only.
- Glued honeycomb joints do not conduct electricity in a direction perpendicular to the strip of foil and can result in electromagnetic leakage.
- Omnidirectional conductivity provides optimum performance rendering glued joints less desirable than the welded or braised joints. There is a need, therefore for a less expensive electromagnetic interference and emission shielding device for air flow vents.
- U.S. Patent #5,032,689 discloses conventional EM1/RFI shielding vent filter media including honeycomb structures, woven screen panels and expanded or perforated metal. All structures disclosed are believed to be metal in order to provide the necessary conductive feature. Expanded metal is disclosed as the preferred media. Disadvantageously, it is difficult to easily control the cell sizes and cell depth of the media in expanded metal and woven screen. Cell size and cell depth together determine air flow volume, cut-off frequency, and attenuation at the cutoff frequency. There is a need, therefore, for a filter media capable of cost effective manufacture wherein the cutoff frequency and attenuation may be reliably controlled.
- a method of manufacturing an electromagnetic shielding device comprises the steps of forming a plastic honeycomb and applying a conductive coating thereto.
- a method of fabricating an electromagnetic shielding device comprises the steps of forming a plastic honeycomb, cutting the honeycomb to a desired dimension, disposing a frame around a perimeter of the honeycomb and applying a conductive coating to the honeycomb and frame.
- Figure 1 is a perspective view of a honeycomb comprising an array of polycarbonate tubes according to the teachings of the present invention.
- Figure 2 is a cross section of the array pictured in Figure 1 of the drawings.
- Figure 3 is a perspective view of a iTra e and honeycomb for use with an electromagnetic shielding device according to the teachings of the present invention.
- Figure 4 is a cross sectional view of the frame and honeycomb pictured in Figure 3.
- the honeycomb (1) comprises an array of polycarbonate tubes (2) as shown in Figure 1, each tube (2) creating a cell of the honeycomb.
- the tubes (2) are stacked in staggered lines so that each single tube (2) internal to the array has a joint (3) in common with each of six adjacent tubes (2) .
- the array is formed by cutting polycarbonate tubes (2) to a uniform and appropriate length.
- the tubeb (2) are vibrated against a planar member. The vibration results in a configuration comprising staggered lines (4) of tubes (2) stacked on top of each other.
- the center of each tube (2) is collinear with the center of adjacent tubes (2) in a single direction to form the line (4) .
- the planar member acts as an alignment guide to create a planar face for the honeycomb (1) .
- the stacked array of loose tubes (2) is captivated to retain alignment and is immersed in a dissolving solution sufficient to partially dissolve the tubes (2) .
- the array of partially dissolved tubes (2) is removed from the solution and permitted to cure. Curing of the partially dissolved tubes (2) creates the joint (3) at each point on the tube (2) that touches an adjacent tube (2) .
- the array (1) of tubes resolidifies in fixed relation to each other to create the honeycomb (1) .
- An embodiment of the honeycomb (l) for use in a preferred embodiment of an electromagnetic shielding device according to the teachings of the present invention is available from
- honeycomb core Plascore under the name PC Polycarbonate Honeycomb core.
- the resulting honeycomb (1) can be cut to appropriate dimensions for mounting over an air flow vent in an electronic instrument.
- the appropriately dimensioned honeycomb (1) fits into a frame (5) that enables mounting of the shielding device over an air flow vent of an electronic instrument for fixed attachment thereto.
- the frame (5) is substantially rectangular and has mounting holes (6) around the perimeter of the frame (5) .
- Each side of the frame (5) comprises a length of polycarbonate material extruded to form a C-shaped cross section as illustrated in Figure 4 of the drawings. Distal ends (7) of the C of the cross section are separated by a distance larger than the thickness of the honeycomb (1) .
- Frame (5) further comprises compression stop (10) and integral gasket (11) .
- Each of four lengths comprising the sides of the frame (5) are disposed over the honeycomb (1) to complete the structure of the framed shielding device.
- the honeycomb (1) and frame (5) are then plated with a conductive coating.
- the honeycomb (1) and frame (5) are preferably plated with a first layer of copper to provide electrical conductivity.
- the copper plated honeycomb (1) and frame (5) are then plated with a second layer of nickel to resist corrosion.
- the copper plating provides conductivity in the X and Y directions simultaneously.
- the coated frame (5) and honeycomb (1) are mounted over an air flow vent using threaded screws (8) in mounting holes (6) .
- the integral gasket (11) with the conductive coating is interposed between the frame (5) and the chassis of the electronic instrument.
- integral gasket (11) faces the air flow vent of the electronic instrument and contacts a perimeter of the vent opening. Due to its cantilevered configuration, the gasket (11) is cammed toward the electronic instrument as the mounting screws (8) are tightened.
- the resulting force of the biased gasket (11) provides a positive contact when the shielding device is mounted to the instrument.
- the compression stop (10) provides for a positive stop to prevent overstressing the integral gasket (11) .
- the biased conductive gasket assures conductivity from the honeycomb (1) through the frame and to chassis which is important for effective shielding.
- a forward facing side (9) of the frame (5) flares outwardly slightly to create a lead-in for the honeycomb (1) .
- the honeycomb (1) As the honeycomb (1) is forced into the opening of the frame's (5) cross section, the honeycomb (1) enters an area wherein the thickness of the honeycomb is slightly greater than the opening of the C and is compressed. This compression provides a frictional retention between the honeycomb and the frame.
- the inner diameter of each cell of the honeycomb (1) determines the cut off frequency for which the shielding device may be used.
- the most desirable inner diameter dimension for the tubes of a shielding device according to the teachings of the present invention is selected based upon the wave length of a desired cut off frequency and the desired attenuation for the cut off frequency.
- a high cutoff frequency suggests a small inner diameter for each cell.
- a large volume of air flow necessary to maintain a stable operating temperature suggests a large inner diameter for each cell.
- a 40dB attenuation at 90 GHz is achieved using a 1/16 inch inner diameter and 2 inch depth for each cell.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Abstract
Description
Claims
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US60834196A | 1996-02-28 | 1996-02-28 | |
US60833896A | 1996-02-28 | 1996-02-28 | |
US608338 | 1996-02-28 | ||
US608341 | 1996-02-28 | ||
PCT/US1997/002782 WO1997032459A1 (en) | 1996-02-28 | 1997-02-26 | Shielding device for ventilation panels of electronic instruments and method for manufacture thereof |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0883978A1 true EP0883978A1 (en) | 1998-12-16 |
Family
ID=27085735
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97906734A Withdrawn EP0883978A1 (en) | 1996-02-28 | 1997-02-26 | Shielding device for ventilation panels of electronic instruments and method for manufacture thereof |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0883978A1 (en) |
JP (1) | JP2001503915A (en) |
WO (1) | WO1997032459A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
USRE41594E1 (en) | 2001-12-04 | 2010-08-31 | Laird Technologies, Inc. | Methods and apparatus for EMI shielding |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6018125A (en) * | 1996-11-15 | 2000-01-25 | Collins; Pat Eliot | High frequency EMI shield with air flow for electronic device enclosure |
CA2318433A1 (en) * | 1998-02-17 | 1999-08-19 | Parker-Hannifin Corporation | Emi shielded vent panel and method |
US6360621B1 (en) * | 1999-06-25 | 2002-03-26 | Venturedyne, Ltd. | Environmental testing chamber |
AU6355400A (en) * | 1999-08-17 | 2001-03-13 | Parker-Hannifin Corporation | Emi shielding vent panel |
CA2428848A1 (en) | 2002-05-16 | 2003-11-16 | Parker-Hannifin Corporation | Emi shielding vent panel |
US9345182B2 (en) | 2013-08-27 | 2016-05-17 | Parker-Hannifin Corporation | EMI shielding vent panel frame |
US9370132B2 (en) | 2013-08-27 | 2016-06-14 | Parker-Hannifin Corporation | Homogeneous EMI vent panel and method for preparation thereof |
JP2016171138A (en) * | 2015-03-11 | 2016-09-23 | 株式会社国際電気通信基礎技術研究所 | Shield structure |
WO2017048745A1 (en) * | 2015-09-15 | 2017-03-23 | Parker-Hannifin Corporation | Smart emi vent |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3231663A (en) * | 1962-11-01 | 1966-01-25 | Schwartz Edward | Electromagnetic shield having multiple electroconductive passages |
AT364441B (en) * | 1980-06-13 | 1981-10-27 | Siemens Ag Oesterreich | ELECTROMAGNETIC SHIELDING FOR THROUGHOUT OPENINGS |
NL8401200A (en) * | 1984-04-13 | 1985-11-01 | Fokker Bv | Ventilation panel for electromagnetically screened rooms - is solid metal casting drilled to form matrix of air channels with flange for electrical connection |
US5032689A (en) * | 1989-08-15 | 1991-07-16 | Halligan Brian S | EMI/RFI shielding vent and method of use |
-
1997
- 1997-02-26 EP EP97906734A patent/EP0883978A1/en not_active Withdrawn
- 1997-02-26 WO PCT/US1997/002782 patent/WO1997032459A1/en not_active Application Discontinuation
- 1997-02-26 JP JP53103497A patent/JP2001503915A/en active Pending
Non-Patent Citations (1)
Title |
---|
See references of WO9732459A1 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
USRE41594E1 (en) | 2001-12-04 | 2010-08-31 | Laird Technologies, Inc. | Methods and apparatus for EMI shielding |
USRE42512E1 (en) | 2001-12-04 | 2011-07-05 | Laird Technologies, Inc. | Methods and apparatus for EMI shielding |
Also Published As
Publication number | Publication date |
---|---|
JP2001503915A (en) | 2001-03-21 |
WO1997032459A1 (en) | 1997-09-04 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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GRAG | Despatch of communication of intention to grant |
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17P | Request for examination filed |
Effective date: 19980831 |
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AK | Designated contracting states |
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17Q | First examination report despatched |
Effective date: 19981217 |
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GRAH | Despatch of communication of intention to grant a patent |
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GRAG | Despatch of communication of intention to grant |
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GRAH | Despatch of communication of intention to grant a patent |
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RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: SPECTRUM CONTROL, INC. |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 20000830 |