WO2000030418A1 - Procede de formation d'un revetement de carbone pour la protection electromagnetique de cartes de circuits electroniques aux fins de compatibilite electromagnetique - Google Patents

Procede de formation d'un revetement de carbone pour la protection electromagnetique de cartes de circuits electroniques aux fins de compatibilite electromagnetique Download PDF

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Publication number
WO2000030418A1
WO2000030418A1 PCT/TR1999/000045 TR9900045W WO0030418A1 WO 2000030418 A1 WO2000030418 A1 WO 2000030418A1 TR 9900045 W TR9900045 W TR 9900045W WO 0030418 A1 WO0030418 A1 WO 0030418A1
Authority
WO
WIPO (PCT)
Prior art keywords
printed circuit
circuit board
electronic
high conductivity
layer containing
Prior art date
Application number
PCT/TR1999/000045
Other languages
English (en)
Inventor
Şefik ŞENYÜREK
Ahmet ÇELEBİ
Original Assignee
Beko Elektronik A.Ş.
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
Application filed by Beko Elektronik A.Ş. filed Critical Beko Elektronik A.Ş.
Priority to TR2001/01269T priority Critical patent/TR200101269T2/xx
Priority to AU15950/00A priority patent/AU1595000A/en
Publication of WO2000030418A1 publication Critical patent/WO2000030418A1/fr

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
    • H05K9/0073—Shielding materials
    • H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
    • H05K9/0092—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising electro-conductive pigments, e.g. paint, ink, tampon printing
    • 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
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0213—Electrical arrangements not otherwise provided for
    • H05K1/0216—Reduction of cross-talk, noise or electromagnetic interference
    • H05K1/0218—Reduction of cross-talk, noise or electromagnetic interference by printed shielding conductors, ground planes or power plane

Definitions

  • the present invention relates to a shielding method designed to prevent undesired effects of electromagnetic radiation created by electronic circuit boards.
  • metal screening One of the measures taken against electromagnetic interference in electronic devices is metal screening. Optimising the lengths and positioning of the lines and filtering are also two other important applications. These two last mentioned methods may be inefficient in keeping electromagnetic interference to the lowest level. Due to this fact, the coupling of electric, magnetic and electromagnetic fields present between two units within the same system is suppressed using metal screening method. A screen is located between two units to abate coupling.
  • Metal screen covers used in prior art were too costly. In addition to this the application of the screening on the chassis was not easy and these methods were difficult to apply because of the necessity to realise the grounding at certain points of grounding lines. Shielding with a conducting material was a frequently used method to establish a system without interference. This method is generally accomplished by using nonmagnetic materials such as copper, silver or aluminium. Iron and steel are rarely used instead of non-magnetic materials. The screen is grounded with conductor of low ohmage. Here the aim is to prevent the occurrence of undesirable secondary radiation of induced currents on the screen.
  • Another condition is to provide the shielding by covering the area with a shielding material.
  • the metal plate thus used in shielding is effective but it is difficult to predict undesired effect caused by uncalculated electric and magnetic fields. Therefore whole shielding region is covered by the said metal.
  • the object of hereby invention is to perform a shielding of electronic printed circuit boards using a method which requires few workmanship, simple ways of production and which brings ease in operation.
  • Figure 1 is the sectional view of the stages of carbon printing application to electronic printed circuit boards.
  • FIG 2 is the dispersed view of the stages of carbon printing application to electronic printed circuit boards.
  • the descriptions of the components numbered in the figures are as follows;
  • the hereby preferred method intends to solve the electromagnetic compatibility problem by covering electronic printed circuit board's (1) regions sensitive to electromagnetic interference with paint layer containing high conductivity carbon with appropriate parameters of density, thickness and conductivity.
  • the electrical ground connection is done directly to provide the effectiveness of the shielding.
  • a specific region of the electronic printed circuit board may be screened as well as the entire card surface. The method brings an advantage with regard to flexibility that it provides to production by enabling screening of surfaces of different size and shape.
  • Carbon screen layer weakens electromagnetic wave passing through, due to the ohrnic losses which are calculated approximately using the formula set down under:
  • Attenuation of undesired signal is changing with materials characteristics used in screening as well as with signal's frequency. Attenuation increases with root square of frequency. Attenuation of direct current in metals is zero and it depends on the following parameters:
  • Attenuation level desired to a specific frequency is adjusted by choosing a specific resistivity of materials to be used in shielding and a magnetic permeability thereof. Since the relative magnetic permeability of the materials varies with the frequency, this fact is taken in regard when using magnetic materials.
  • Paint layer containing high conductivity carbon reflects some portion of electromagnetic wave and causes attenuation of the signal passing through. Electromagnetic wave is reflected when passing from one environment to the other having different impedance characteristics. The magnitude of the reflection depends on the difference between the impedances of the environment and of the screen. Screen impedance is the surface impedance of the material used. It is then created an impedance incompatibility which will cause a reflection and therefore an attenuation with the paint layer containing high conductivity carbon. The losses created by the above incompatibility is calculated with the following formula;
  • Zr environmental impedance (to vary between 10 and 1000 )
  • the region to be shielded is prepared according to electronic printed circuit board film preparation techniques.
  • the silk printing film is prepared as a separate layer after having masked the electronic circuit board (1) two times with insulation mask or after having masked the region only one time and then having covered it with an insulation coat.
  • the silk printing film having paint layer containing high conductivity carbon on it is applied onto electronic printed circuit board (1) and dried and hardened after being heated in air-circulated furnace. The grounding is achieved by setting electrical contacts with copper surfaces during this hardening process.
  • a shielding method is achieved by means of a paint layer containing high conductivity carbon and resulting with a solution which is easy, simple and requiring less workmanship. With the help of this method it is possible to perform shielding; 1. between lines

Abstract

On assure la compatibilité électromagnétique d'une carte de circuits imprimés électroniques (1) en recouvrant les régions sensibles de ladite carte (1) avec une couche de peinture contenant du carbone (4) à haute conductivité. Le revêtement constitué de la couche de peinture contenant du carbone (4) à haute conductivité est formé selon un procédé d'impression sur soie permettant de déposer la couche de peinture contenant le carbone à haute conductivité (4) sur la carte de circuit imprimé électronique (1) recouverte soit deux fois avec le masque d'isolement (3) soit une fois avec le masque d'isolement (3) puis avec une couche d'isolement. On sèche ensuite le produit ainsi obtenu dans un four à circulation d'air.
PCT/TR1999/000045 1998-11-13 1999-11-15 Procede de formation d'un revetement de carbone pour la protection electromagnetique de cartes de circuits electroniques aux fins de compatibilite electromagnetique WO2000030418A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
TR2001/01269T TR200101269T2 (tr) 1998-11-13 1999-11-15 Elektronik devre kartlarının elektromanyetik uygunluk sağlanması amacıyla elektromanyetik ekranlanması için karbon ile kaplama yöntemi
AU15950/00A AU1595000A (en) 1998-11-13 1999-11-15 Carbon coating method for electromagnetic shielding of electronic circuit boardsto provide electromagnetic compatibility

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
TR9802320 1998-11-13
TR9802320 1998-11-13

Publications (1)

Publication Number Publication Date
WO2000030418A1 true WO2000030418A1 (fr) 2000-05-25

Family

ID=21621714

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/TR1999/000045 WO2000030418A1 (fr) 1998-11-13 1999-11-15 Procede de formation d'un revetement de carbone pour la protection electromagnetique de cartes de circuits electroniques aux fins de compatibilite electromagnetique

Country Status (3)

Country Link
AU (1) AU1595000A (fr)
TR (1) TR200101269T2 (fr)
WO (1) WO2000030418A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2161974A1 (fr) 2008-09-09 2010-03-10 Hegutechnik v. Gutwald KG Revêtement EMV bi-fonctionnel
EP2519092A1 (fr) * 2009-12-22 2012-10-31 Huawei Device Co., Ltd. Procede pour blinder une carte de circuit imprime et carte de circuit imprime associee

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4490282A (en) * 1983-02-18 1984-12-25 Corboy Thomas A Conductive paint composition
US5112648A (en) * 1990-07-18 1992-05-12 Nippon Cmk Corp. Method of manufacturing a printed circuit board
US5220135A (en) * 1989-03-15 1993-06-15 Nippon Cmk Corp. Printed wiring board having shielding layer

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4490282A (en) * 1983-02-18 1984-12-25 Corboy Thomas A Conductive paint composition
US5220135A (en) * 1989-03-15 1993-06-15 Nippon Cmk Corp. Printed wiring board having shielding layer
US5112648A (en) * 1990-07-18 1992-05-12 Nippon Cmk Corp. Method of manufacturing a printed circuit board

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2161974A1 (fr) 2008-09-09 2010-03-10 Hegutechnik v. Gutwald KG Revêtement EMV bi-fonctionnel
EP2519092A1 (fr) * 2009-12-22 2012-10-31 Huawei Device Co., Ltd. Procede pour blinder une carte de circuit imprime et carte de circuit imprime associee
EP2519092A4 (fr) * 2009-12-22 2012-12-26 Huawei Device Co Ltd Procede pour blinder une carte de circuit imprime et carte de circuit imprime associee

Also Published As

Publication number Publication date
TR200101269T2 (tr) 2002-01-21
AU1595000A (en) 2000-06-05

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