Electricity: conductors and insulators – Anti-inductive structures – Conductor transposition
Reexamination Certificate
2000-06-05
2002-03-12
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Anti-inductive structures
Conductor transposition
C174S034000, C277S920000
Reexamination Certificate
active
06355878
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application entitled Clip Type Conductive Gasket earlier filed in the Korean Industrial Property Office on Dec. 24, 1999, and there duly assigned Ser. No. 99-29499 by that Office.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a conductive gasket, and more particularly, a clip type conductive gasket in which a liquid phase conductive elastic body is provided and cured on a metal finger gasket.
2. Description of the Background Art
Electromagnetic Interference (EMI) concerns an undesirable electrical or electronic interference that is induced or radiated from an electric or electronic apparatus. Radio Frequency Interference (RFI) typically means an electromagnetic wave interference, particularly, the electromagnetic wave interference in a radio frequency band of 10 kHz~10 GHz.
In order to solve the problem of the electromagnetic wave interference in the electric or electronic apparatus, there are many proposed technical methods. Mainly, a method of blocking EMI/RFI is used. In order to block the EMI/RFI, a conductive gasket which absorbs or reflects the EMI/RFI energy and reduces the energy level is provided between the EMI/RFI generating sources or inserted into a place where the EMI/RFI should be blocked. Thus, the conductive gasket forms a conductive barrier between the EMI/RFI generating sources so as to block the EMI/RFI energy, or forms a conductive passage so as to exhaust the EMI/RFI energy by a grounding. This conductive gasket is employed in various fields, for example, a personal communication system.
The conventional embodiments have some problems. First, in case of the conductive elastic gasket, there is a problem that the conductive elastic gasket is easily separated from a conductive rib formed on an electrical apparatus. Particularly, in case that the surface of the conductive rib is so smooth, the interfacial adhesive force between the surface of the conductive rib and the conductive elastic gasket is lowered. Therefore, the conductive elastic gasket is easily separated from the conductive rib. Further, conductive particles distributed in the conductive elastic body are unequally contacted with the surface of the conductive rib, thus an electrical contact resistance therebetween is increased or an electrical conductivity therebetween is decreased. In addition, if a place, to which the conductive elastic gasket is applied, has a small surface, the precise dispenser attached to a three-axis CNC (Computer Numerical Control) robot is needed for dispensing the conductive elastic gasket. Thus, another problem is that the manufacturing cost is increased.
Meanwhile, in a case of a conductive metal finger gasket, since the finger gasket is electrically connected with the conductive member only by the contact of the elastic protrusion of the finger gasket, the contact area is therefore so small that there is a problem of an increased electrical contact resistance. Further, the number of the elastic protrusions is restrained due to the limited size of the finger gasket. Since the conductive member is electrically and mechanically connected with the only elastic protrusion of the finger gasket, when the conductive member is closely contacted with the finger gasket, the EMI/RFI energy is leaked from a portion between the conductive member and the finger gasket, in which the elastic protrusion is not provided.
Exemplars of the background art U.S. Pat. No. 4,659,869 for Clip-On Strip for RFI/EMI Shielding issued to Busby, U.S. Pat. No. 4,820,885 for Magnetic Gasket for Shielding Against Electromagnetic Radiation issued to Lindsay, U.S. Pat. No. 5,977,480 for Grounding and RFI isolation for Control Station issued to Timieski, U.S. Pat. No. 5,028,739 for EMl/RFI Gasket issued to Keyser et al., U.S. Pat. No. 5,539,149 for Radio Frequency Interference Gasket issued to Gatti, U.S. Pat. No. 5,524,908 for Multi-Layer EMI/RFI Gasket Shield issued to Reis, U.S. Pat. No. 4,525,904 for RF Gasket Retainer Clip issued to Petri disclose gaskets for reducing electromagnetic interference and particularly radio frequency interference.
I have found that the background art does not show a single piece clip type gasket that reduces electromagnetic interference and particularly radio frequency interference while reducing the contact resistance and lowering the cost of manufacture.
SUMMARY OF THE INVENTION
The present invention has been made to overcome the above described problems of the background art, and accordingly, it is therefore an object of the present invention to provide a conductive gasket in which a physical binding force is increased.
It is another object to provide a conductive gasket in which an electrical conductivity is equal and the contact area is increased so that the contact resistance is lowered.
It is a further object to provide a conductive gasket that lowers the manufacturing cost.
It is yet another object to provide a conductive gasket that reduces electromagnetic interference and particularly radio frequency interference.
To achieve the above objects and other advantages, there is provided a clip type conductive gasket that is applied to an electric or electronic apparatus to be electrically connected or electrically block EMI/RFI having a conductive metal finger strip that is fitted to a part of the apparatus; and a conductive elastic body that is dispensed on an upper portion of the conductive metal finger strip.
It is preferable that the conductive metal finger strip has a desired length and forms a square pillar which is opened at one side of the square pillar, and the conductive metal finger strip is formed with a bent portion at each side of the conductive metal finger strip. Further, it is preferable that the conductive metal finger strip is an elastic metal and the conductive elastic body contains conductive particles.
REFERENCES:
patent: 4525904 (1985-07-01), Petri
patent: 4659869 (1987-04-01), Busby
patent: 4820885 (1989-04-01), Lindsay
patent: 4937128 (1990-06-01), Quiles
patent: 5028739 (1991-07-01), Keyser et al.
patent: 5068493 (1991-11-01), Benn, Sr. et al.
patent: 5107070 (1992-04-01), Benn, Sr. et al.
patent: 5205751 (1993-04-01), Schwartz et al.
patent: 5250751 (1993-10-01), Yamaguchi
patent: 5524908 (1996-06-01), Reis
patent: 5539149 (1996-07-01), Gatti
patent: 5977480 (1999-11-01), Timieski
patent: 6096413 (2000-08-01), Kalinoski et al.
patent: 6188014 (2001-02-01), Richard et al.
Bushnell , Esq. Robert E.
Expan Electronics Co., Ltd.
Oliva Carmelo
Reichard Dean A.
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