Electrical connectors – Electromagnetic or electrostatic shield – Multi-part shield body
Patent
1997-01-13
1999-10-05
Bradley, Paula
Electrical connectors
Electromagnetic or electrostatic shield
Multi-part shield body
439 63, H01R 13658
Patent
active
059613491
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an assembly comprising at least one connector and a board, each connector being connected to a predetermined side of said board and comprising at least one signal contact member fitted in a hole of the board, the connector comprising electrically conductive connector shielding means to shield each signal contact member.
Such an assembly is known from U.S. Pat. No. 4,874,319, which is assigned to the Applicant of the present patent application and describes a connector-board connection to reduce the adverse effects of electromagnetic radiation generated by signal contact members extending from the connector into the board. The known connector comprises a series of leaf-type spring ground contacts positioned on opposite sides of the signal contact members within the connector. A right-angle connection is present between the connector and the board. To establish this right-angle connection, the signal contact members and the leaf-type spring ground contacts each extend from the rear side of the connector and are bend over 90.degree.. However, the signal contact members extend, unshielded, through corresponding through-holes in the board and are not entirely shielded. When very high frequencies, e.g. within the frequency range from 50 MHz to 15 GHz, are used they still act as antennas radiating undesired electromagnetic radiation.
U.S. Pat. No. 4,697,858 discloses connections between a backplane and several printed circuit boards (pcb's) (FIG. 5). One side of the backplane carries several chip elements each having several terminals. For example as shown in FIG. 7, some of those chip terminals are connected to inner bus lines within the backplane through blind holes reaching as deep as the depth of the corresponding bus lines. Other chip terminals are connected to an inner ground plane through blind holes reaching as deep as the depth of that inner ground plane. Still other signal carrying chip terminals are connected to signal pins extending from the pcb's by means of signal contact members extending entirely through the backplane. These signal contact members extend from connectors accommodating the pcb's and being arranged at the side of the backplane opposite the side carrying the chip elements. None of said connectors is shielded and the signal contact members extend unshielded through said backplane. The bus line within the backplane is situated between two separate ground planes in order to establish a well defined impedance level. No EMC protective measures are provided for.
The present invention starts from the problem that in existing equipment signal contact members of a connector connected to a board, e.g. a pcb or a backplane, extend entirely through plated through-holes and generate electromagnetic radiation also at the opposite side of the board. This will be explained referring to FIG. 1. FIG. 1 shows a connection between a connector 42 and a board 41, e.g. a pcb or a backplane. One signal contact member 43 is schematically shown extending from the connector 42 through a plated through-hole 40. It is to be understood that "signal contact member" is to be conceived as referring to those contact members of the connector 42 that are intended to carry signals during operation, i.e. the not-ground members.
The connector 42 is provided with an electrically conductive layer 47 to shield contact member 43. Therefore, connector 42 is suited as coaxial connector.
In existing connector-board connections each signal contact member 43 extends from the through-hole 40 at the side of the board 41 opposite the connector 42 or at least reaches the other side of the board 41, as shown in FIG. 16 of International Patent Application WO-NL-94/00075 filed on Apr. 12, 1994, by the Applicant of the present patent application. Since the end part of the signal contact member 43 extending from the board 41 is not shielded it acts like an antenna and radiates electromagnetic radiation which might induce cross-talk or affect adjacent circuit elements.
The object of the present invention is t
REFERENCES:
patent: 3681744 (1972-08-01), Olsson
patent: 4506939 (1985-03-01), Faulkenberry et al.
patent: 4952896 (1990-08-01), Dawson, Jr.
patent: 5046966 (1991-09-01), Snyder et al.
patent: 5199879 (1993-04-01), Kohn et al.
Berg Technology Inc.
Bradley Paula
Long Daniel J.
Page M. Richard
Ta Tho Dac
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