Method and apparatus using photoresistive materials as switchable EMI barriers and shielding
First Claim
1. A method of protecting an object against electromagnetic radiation, which comprises the steps of:
- providing an object to be protected from electromagnetic radiation;
placing a barrier sheet adjacent to said object, said sheet including a layer of a photoresistive material which is opaque to said radiation when exposed to visible light;
directing said light against said sheet when a barrier to said radiation is desired; and
extinguishing said light when passage of said radiation through said sheet is desired.
2 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for providing a switchable electromagnetic interference (EMI) barrier. The method protects an object against electromagnetic radiation, through the steps of: providing an object to be protected from electromagnetic radiation; placing a barrier sheet adjacent to the object, the sheet being opaque to radiation when exposed to light; directing the light against the sheet when a barrier to the radiation is desired; and extinguishing the light when passage of the radiation through the sheet is desired. One embodiment is a switchable electromagnetic radiation barrier system that includes a photoresistive sheet interposed between a source of electromagnetic radiation and an object to be protected from the radiation. This sheet is opaque to the radiation when exposed to light of a selected visible intensity range. A light source adjacent to this sheet directs the light against the sheet. A second embodiment is an apparatus for protecting an EMI-sensitive device in an air vehicle from external electromagnetic radiation (EMR). The apparatus includes: a cavity in an air vehicle; an EMI-sensitive device in the cavity; and a barrier window covering the cavity. The window includes a support sheet having a layer of photoresistive material. This material transmits EMR when exposed to light and does not transmit EMR when unlighted. A light source is provided to selectively illuminate the layer. Another embodiment is an antenna element of layered sandwich construction, including a polyimide film layer. Switchable means are used in the embodiments to turn the light source off and on.
41 Citations
18 Claims
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1. A method of protecting an object against electromagnetic radiation, which comprises the steps of:
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providing an object to be protected from electromagnetic radiation; placing a barrier sheet adjacent to said object, said sheet including a layer of a photoresistive material which is opaque to said radiation when exposed to visible light; directing said light against said sheet when a barrier to said radiation is desired; and extinguishing said light when passage of said radiation through said sheet is desired.
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2. A switchable electromagnetic radiation barrier system, which comprises:
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a photoresistive sheet interposed between a source of electromagnetic radiation and an object to be protected from said radiation; said sheet including a layer of a photoresistive material which is transparent to said radiation in the absence of light and opaque to said radiation when exposed to visible light; a light source in approximate vicinity to said sheet adapted to direct said light against said sheet; and means for turning said light source off and on. - View Dependent Claims (3, 4, 5, 6, 7, 8)
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9. Apparatus for protecting an electromagnetic interference (EMI) sensitive device in an air vehicle from external electromagnetic radiation (EMR) which comprises:
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a cavity in an air vehicle; an EMI-sensitive device in said cavity; a barrier window covering said cavity; said window comprising a support sheet having a photoresistive material coating thereon; said material coating transmitting EMR when exposed to light and not transmitting EMR when unlighted; a light source adapted to selectively illuminate said coating; and
switchable means to turn said light off and on. - View Dependent Claims (10, 11, 12, 13)
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14. An antenna of layered sandwich construction, which comprises:
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a thin film electro-illuminescent solid state lamp and antenna ground plane layer; a transparent dielectric sandwich layer; a polyimide film layer with a photoresistive material coating; a polyurethane topcoat layer; and a protective SiO2 coating layer. - View Dependent Claims (15, 16, 17, 18)
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Specification