Leakage radiation preventing element

• US 5,783,772 A
• Filed: 10/07/1996
• Issued: 07/21/1998
• Est. Priority Date: 04/09/1996
• Status: Expired due to Fees

• Current Assignee: URO Denshi Kogyo Kabushiki Kaisha
• Original Assignee: URO Denshi Kogyo Kabushiki Kaisha
• Inventors: Komine, Hitoshi, Ichikawa, Yuji, Takahashi, Michiharu
• Primary Examiner(s): Kincaid, Kristine L.
• Assistant Examiner(s): Ngo, Hung V.
• Application Number:
  US08/726,493
• Time in Patent Office: 652 Days
• Field of Search: 361/307, 361/816, 361/818, 174/152 R, 174/152 GM, 174/143, 174/35 R, 333/182, 333/183, 333/12, 336/84 R, 336/84 C, 336/84 M
• US Class Current: 174/360
• CPC Class Codes: H05K 9/0018 with provisions to reduce aperture leakages in walls, e.g. terminals, connectors, cables

Abstract

A novel leakage radiation preventing element effectively prevents radio waves from being radiated from an electronic appliance, without depending upon a capacitor or a choke coil. The leaked current I_os and I_or generated from a hole or a gap formed in a casing or a chassis is introduced into a wave guide path and then attenuated by radio wave absorption function of a magnetic substance disposed therein. A coaxial conductor (2) is passed through a hole (107) formed in a chassis (3). The wave guide path (104) is formed between the chassis and a conductive disk (101) electrically floated from the chassis. A radially outward end of the wave guide path (i.e., the outer circumferential end of the conductive disk) is shorted to the chassis at high frequency, and further the inside of the wave guide path is filled with a ferrite ring (102). Therefore, when being propagated along the wave guide path, the high frequency current leaked from the hole or gap of the chassis is absorbed by the ferrite ring, without being radiated to the outside.

Claims

1. A leakage radiation preventing element, comprising:

a coaxial conductor composed of an inner conductor and an outer conductor and disposed so as to pass through a chassis of an electronic appliance electrically insulated from the chassis;

a conductive disk connected to the outer conductor of said coaxial conductor and extending roughly in parallel to the chassis so as to form a space between said conductive disk and the chassis by surrounding said coaxial conductor concentrically; and

a magnetic substance formed of ferrite and inserted in the space so as to surround said coaxial conductor concentrically.

2. The leakage radiation preventing element of claim 1, wherein a gap or a dielectric substance is inserted between the chassis and said conductive disk and further between the chassis and said magnetic substance.

3. The leakage radiation preventing element of claim 1, wherein an electric capacitance is additionally disposed between said conductive disk and the chassis.

4. A leakage radiation preventing element disposed between a cable television subscriber terminal and a lead-in wire so as to be used as a protector, which comprises:

a conductive disk attached concentrically to an outer conductor of a coaxial connector electrically insulated from a chassis or a casing of the protector; and

a magnetic substance interposed between said conductive disk and the chassis or the casing.

5. The leakage radiation preventing element of claim 4, wherein a gap or a dielectric substance is inserted between the chassis or the casing and said conductive disk and further between the chassis or the casing and said magnetic substance.

6. The leakage radiation preventing element of claim 4, wherein an electric capacitance is additionally disposed between said conductive disk and the chassis or the casing.

7. A leakage radiation preventing element, which comprises:

a ring-shaped magnetic substance formed with at least one slit extending in thickness direction or in radial direction thereof, the slit being filled with a conductive plate, and a wire led out of a casing of an electronic appliance to an outside of the casing being passed through a roughly central portion of said magnetic substance; and

a conductive disk arranged concentrically with said magnetic substance and connected to the conductive plate.

8. The leakage radiation preventing element of claim 7, wherein said magnetic substance is formed by arranging a plurality of magnetic substances having a different axial thickness, respectively at a multi-stage in a radial direction thereof.

9. A leakage radiation preventing element, comprising:

a conductor disposed to pass through a chassis of an electronic appliance, said conductor being electrically insulated from the chassis;

a conductive disk connected to said conductor and extending roughly in parallel to the chassis so as to form a space between said conductive disk and the chassis by surrounding said conductor concentrically; and

a magnetic substance formed of ferrite and inserted in the space so as to surround said conductor concentrically.

10. A leakage radiation preventing element of claim 9, wherein a gap or a dielectric substance is inserted between the chassis and said conductive disk and further between the chassis and said magnetic substance.

11. The leakage radiation preventing element of claim 9, wherein a capacitor is additionally disposed between said conductive disk and the chassis.