发明名称 |
ELECTRO-MAGNETIC SHIELD AND METHOD FOR MAKING THE SAME |
摘要 |
An enclosure for an electronic device forms a barrier to electro-magnetic radiation. A typical cross-section of the enclosure comprises three parallel layers. The outer and inner surface layers are of a polymeric base material in which is suspended an electrically conductive fill material, giving the surface layers relatively high electrical conductivity. The middle layer is of a polymeric base material, in which is suspended fill material having high magnetic permeability, giving the middle layer relatively high magnetic permeability. In the preferred embodiment, the enclosure is constructed using a co-injection molding process. Nickel-coated graphite (high conductivity) in a polymeric base is injected into a mold from the outer co-injection nozzle, while carbonyl iron powder (high permeability) in a polymeric base is injected into the mold from the inner co-injection nozzle. The resultant molded structure contains the three layers described above, yet can be made inexpensively in a single co-injection molding operation. The enclosure may comprise multiple co-injection molded pieces, which are attached together by any of various conventional means. |
申请公布号 |
CA2080177(C) |
申请公布日期 |
1997.02.25 |
申请号 |
CA19922080177 |
申请日期 |
1992.10.08 |
申请人 |
INTERNATIONAL BUSINESS MACHINES CORPORATION |
发明人 |
HIGHUM, EDWARD ALLAN;MUELLER, ALFRED WILHELM;NASH, THOMAS WILLIAM;STADLER, EWALD EMIL GOTTLOB;THORVILSON, SCOTT MARVIN |
分类号 |
B29C45/00;B29C45/16;B29C70/88;B32B5/00;B32B7/02;B32B27/18;H05K9/00;(IPC1-7):H05K9/00 |
主分类号 |
B29C45/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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