Claims
- 1. A case having an electromagnetic wave shielding structure, comprising:
- a conductive film disposed on an inner surface of said case; and
- a magnetically lossy layer disposed on said conductive film, said conductive film being disposed between said magnetically lossy layer and said inner surface of said case,
- said magnetically lossy layer containing ferrite particles, having a thickness (d) of 80 to 300 .mu.m and a loss term (.mu.") of relative magnetic permeability of not less than 1.9 and satisfying the following inequality:
- .mu.".gtoreq.145/(f.times.d)
- where f is a frequency given in GHz of an incident electro-magnetic wave and d is given in .mu.m, wherein said ferrite particles have an average diameter of 1 to 20 .mu.m.
- 2. An electromagnetic wave shielding structure according to claim 1, wherein said ferrite particles are Mn--Mg--Zn group soft ferrite particles.
- 3. An electromagnetic wave shielding structure according to claim 1, wherein said conductive film has a thickness of about 40-70 .mu.m.
- 4. An electromagnetic wave shielding structure according to claim 1, wherein said conductive film comprises a resin selected from a Cu-Ag/acryl resin group.
- 5. An electromagnetic wave shielding structure according to claim 4, wherein said conductive film has a thickness of about 40-70 .mu.m.
- 6. An electromagnetic wave shielding structure comprising:
- a conductive film disposed on an inner surface of said case; and
- a magnetically lossy layer disposed on said conductive film, said conductive film being disposed between said magnetically lossy layer and said inner surface of said case,
- said magnetically lossy layer containing ferrite particles, having a thickness (d) of 80 to 300 .mu.m and a loss term (.mu.") of relative magnetic permeability of not less 1.9 and satisfying the following inequality:
- .mu.".gtoreq.145/(f.times.d)
- where f is a frequency given in GHz of an incident electro-magnetic wave and d is given in .mu.m, wherein said ferrite particles comprise 70-90% by weight of said magnetically lossy layer.
- 7. An electromagnetic wave shielding structure according to claim 6, wherein said ferrite particles are Mn--Mg--Zn group soft ferrite particles.
- 8. An electromagnetic wave shielding structure according to claim 6, wherein said conductive film has a thickness of about 40-70 .mu.m.
- 9. An electromagnetic wave shielding structure according to claim 6, wherein said conductive film comprises a resin selected from a Cu-Ag/acryl resin group.
- 10. An electromagnetic wave shielding structure according to claim 9, wherein said conductive film has a thickness of about 40-70 .mu.m.
Priority Claims (1)
Number |
Date |
Country |
Kind |
4-243654 |
Sep 1992 |
JPX |
|
Parent Case Info
This application is a continuation-in-part of application Ser. No. 08/117,756, filed Sep. 8, 1993.
US Referenced Citations (7)
Foreign Referenced Citations (4)
Number |
Date |
Country |
0398672A1 |
Nov 1990 |
EPX |
2855134 |
Jun 1979 |
DEX |
0271599 |
Nov 1990 |
JPX |
0302098 |
Dec 1990 |
JPX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
117756 |
Sep 1993 |
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