Emi shielding having flexible conductive envelope
First Claim
1. A shielding enclosure comprising:
- an electrically insulating flexible sheet;
a sheet of conductive fibers embedded in the flexible sheet and spaced from at least one side of the flexible sheet so as to present an insulating face at least on said at least one side;
wherein the flexible sheet and the embedded fibers are formed into a loose and flexible bag enclosure sized to substantially surround at least one electrical circuit, with the insulating face oriented inwardly toward the electrical circuit, the flexible sheet following the contour of the electrical circuit and the embedded fibers forming a substantially continuous shielding barrier around the enclosure; and
,means for coupling the conductive fibers to a circuit ground of the electrical circuit.
3 Assignments
0 Petitions
Accused Products
Abstract
An electronic device such as a portable computer is shielded against electromagnetic interference using a flexible envelope that surrounds a circuit card within the housing of the device. The flexible envelope forms a shielding enclosure and has an electrically insulating flexible sheet, for example of polyethylene, and a sheet of conductive fibers embedded in the flexible sheet so as to leave a nonconductive face oriented toward the circuit card. The conductive fibers can be metallized nylon and are sufficiently dense to obtain a resistivity of 10-1 to 10-2 Ω/□. The enclosure forms a hollow envelope with the conductive fibers coupled electrically across a seam, for example by cutting the flexible sheet and embedded fibers using heat. For use with a portable computer having a pivoting screen, a neck extension of the enclosure carries conductors through the area of the pivot. For access to circuit board elements, for example for changing or adding chips, an access opening is provided with a conductive extension that is movable to overlap the opening or to expose the opening. The flexible envelope can be joined to a circuit ground by clamping conductive fibers on an exposed face to a metal connector panel of the device.
106 Citations
22 Claims
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1. A shielding enclosure comprising:
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an electrically insulating flexible sheet; a sheet of conductive fibers embedded in the flexible sheet and spaced from at least one side of the flexible sheet so as to present an insulating face at least on said at least one side; wherein the flexible sheet and the embedded fibers are formed into a loose and flexible bag enclosure sized to substantially surround at least one electrical circuit, with the insulating face oriented inwardly toward the electrical circuit, the flexible sheet following the contour of the electrical circuit and the embedded fibers forming a substantially continuous shielding barrier around the enclosure; and
,means for coupling the conductive fibers to a circuit ground of the electrical circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A shielding enclosure comprising:
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an electrically insulating flexible sheet; a sheet of conductive fibers embedded in the flexible sheet, the conductive fibers being sufficiently dense to obtain a resistivity of 10-1 to 10-2 Ω
/□
, the fibers being spaced from at least one side of the flexible sheet forming an insulating face;wherein the flexible sheet and the embedded fibers are formed into a loose and flexible bag enclosure sized to substantially surround at least one electrical circuit, with the insulating face oriented inwardly toward the electrical circuit, the flexible sheet being non-molded and following the contour of the electrical circuit and the embedded fibers forming a substantially continuous shielding barrier around the enclosure; and
,means for coupling the conductive fibers to a circuit ground of the electrical circuit; and
,wherein the enclosure is formed into a hollow envelope by at least one seam, and further comprising means for electrically coupling the conductive fibers across the seam. - View Dependent Claims (9, 10)
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11. A shielding enclosure comprising:
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an electrically insulating flexible sheet; a sheet of conductive fibers embedded in the flexible sheet, the conductive fibers being sufficiently dense to obtain a resistivity of 10-1 to 10-2 Ω
/□
, the fibers being spaced from at least one side of the flexible sheet forming an insulating face;wherein the flexible sheet and the embedded fibers are formed into a loose and flexible bag enclosure sized to substantially surround at least one electrical circuit, with the insulating face oriented inwardly toward the electrical circuit, the flexible sheet conforming loosely to the electrical circuit and the embedded fibers forming a substantially continuous shielding barrier around the enclosure; and
,means for coupling the conductive fibers to a circuit ground of the electrical circuit; at least one neck extension of the enclosure, dimensioned for passage of at least one conductor; and
,wherein the electrically insulating flexible sheet comprises a thermoplastic material with the conductive fibers embedded therein, having layers arranged to define at least one seam bordering at least one of the enclosure and the neck extension, and wherein the seam comprises a melted and reformed line along the thermoplastic material at which the conductive fibers are in electrical contact across the seam.
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12. A shielding enclosure comprising:
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an electrically insulating flexible sheet; a sheet of conductive fibers embedded in the flexible sheet, the conductive fibers being sufficiently dense to obtain a resistivity of 10-1 to 10-2 Ω
/□
, the fibers being spaced from at least one side of the flexible sheet forming an insulating face;wherein the flexible sheet and the embedded fibers are formed into a loose and flexible bag enclosure sized to substantially surround at least one electrical circuit, with the insulating face oriented inwardly toward the electrical circuit, the flexible sheet being non-molded and following the contour of the electrical circuit and the embedded fibers forming a substantially continuous shielding barrier around the enclosure; and
,means for coupling the conductive fibers to a circuit ground of the electrical circuit; and
,wherein the enclosure defines at least one access opening, and further comprising an extension of the enclosure adjacent the access opening and dimensioned to cover the access opening, conductive fibers of the extension being electrically coupled to the conductive fibers of the sheet of conductive fibers such that the extension continues the shielding barrier across the access opening.
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13. A shielding enclosure comprising:
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an electrically insulating flexible sheet; a sheet of conductive fibers embedded in the flexible sheet, the conductive fibers being sufficiently dense to obtain a resistivity of 10-1 to 10-2 Ω
/□
, the fibers being spaced from at least one side of the flexible sheet forming an insulating face;wherein the flexible sheet and the embedded fibers are formed into a loose and flexible bag enclosure sized to substantially surround at least one electrical circuit, with the insulating face oriented inwardly toward the electrical circuit, the flexible sheet being non-molded and following the contour of the electrical circuit and the embedded fibers forming a substantially continuous shielding barrier around the enclosure; and
,means for coupling the conductive fibers to a circuit ground of the electrical circuit; wherein the conductive fibers comprise a nonwoven sheet of metallized thermoplastic fibers including nylon, the electrically insulating flexible sheet comprises a thermoplastic material including polyethylene; and
,wherein the enclosure is formed with at least one seam at which the electrically insulating flexible sheet is melted and reformed so as to join the conductive fibers electrically across the seam, the seam defining at least one of a neck extension of the enclosure, dimensioned for passage of at least one conductor, and an access flap at which a portion of the enclosure is displaceable to obtain access to an inside of the enclosure.
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14. A shielding electronic device, comprising:
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at least one electrical circuit carrying circuit element; a substantially rigid housing for enclosing the electrical circuit; a flexible shielding enclosure disposed around the electrical circuit and inside the housing, the shielding enclosure including an electrically insulating flexible sheet with a sheet of conductive fibers embedded in the flexible sheet so as to be spaced from at least one surface of the flexible sheet forming an insulating face oriented inwardly toward the electrical circuit, the flexible sheet forming a loose and flexible bag enclosure conforming to the electrical circuit and the embedded fibers forming a substantially continuous shielding barrier around the enclosure, the conductive fibers being sufficiently dense to obtain a resistivity of 10-1 to 10-2 Ω
/□
, the flexible shielding enclosure having at least one seam at which adjacent portions of the conductive sheet are arranged to continue a shielding barrier formed by the conductive fibers across the adjacent portions; and
,means for coupling the conductive fibers to a circuit ground of the electrical circuit. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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Specification