Noise rejection device and cellular phone including the noise rejection device

• US 7,358,843 B2
• Filed: 09/29/2005
• Issued: 04/15/2008
• Est. Priority Date: 09/30/2004
• Status: Expired due to Fees

• Current Assignee: Taiyo Yuden Company Limited (Taiyo Yuden Co), Wakayama Taiyo Yuden Co., Ltd. (Taiyo Yuden Co)
• Original Assignee: Taiyo Yuden Company Limited (Taiyo Yuden Co)
• Inventors: Kakiuchi, Ikuo, Tosaka, Shoichi, Shiga, Takashige, Maeda, Masaru, Takayama, Manabu
• Primary Examiner(s): Nguyen; Tuyen T.
• Application Number:
  US11/240,015
• Publication Number:
  US 20060125569A1
• Time in Patent Office: 929 Days
• Field of Search: 336/65, 336/83, 336/84.R, 336/84.C, 336/192, 336/200, 336/232
• US Class Current: 336/200
• CPC Class Codes: H04B 15/02 Reducing interference from electric apparatus by means located at or near the interfering apparatus

Abstract

A device includes: a pillar-shaped core consisting of a first magnetic insulating material that has two quadric prism segments at both ends thereof symmetrically and has a cylindrical segment, which has an external shape smaller than that of the quadric prism segments, coaxially between the two quadric prism segments; a resistance film that is formed in a substantially uniform thickness so as to cover an outer circumferential face of the pillar-shaped core; a spiral line segment having a predetermined number of circumferences that is formed in a portion present on the cylindrical segment of the resistance film by subjecting a spiral sulcus to laser trimming; an oxide film that is formed to cover at least a surface of a shoulder portion extending from a side to an upper surface of lines constituting the spiral line segment; an armor consisting of a second magnetic insulating material that is formed to cover a surface of the portion present on the cylindrical segment of the resistance film and such that an external shape the armor is a quadric prism shape; and a pair of external electrodes that are formed in a substantially equal thickness so as to cover surfaces of portions present on an end face and four sides of the respective quadric prism segments of the resistance film.

Claims

1. A noise rejection device comprising:

a core comprising a first magnetic insulating material having a resonant frequency of permeability equal to or higher than 100 MHz;

a resistance film formed on an outer peripheral face of the core from one end to the other end in an axial direction of the outer peripheral face;

a spiral line segment and a corresponding spiral sulcus, each having a predetermined number of circumferences formed in the resistance film in an axial direction of the resistance film;

an oxide film formed over a surface of at least a shoulder portion extending from a side to an upper surface of lines constituting the spiral line segment;

an armor comprising a second magnetic insulating material having a dielectric constant smaller than that of the first magnetic insulating material, filling the spiral sulcus in the central part in the axial direction of the resistance film and covering a surface of the lines constituting the spiral line segment; and

a pair of external electrodes formed in portions at both ends in the axial direction of the resistance film so as to sandwich the armor.

2. A noise rejection device according to claim 1, wherein a resistivity of the resistance film is in a range of 7 to 1000×

10<sup>−

8</sup> Ω

m.

3. A noise rejection device according to claim 1, wherein

the oxide film comprises molten scatters at the time of laser trimming, wherein the molten scatters contain a first magnetic insulating material element.

4. A noise rejection device according to claim 1, wherein the armor comprises magnetic powder containing plastics comprising 30 to 90 wt % of at least one of Ni—

Zn spinel ferrite powder, Mn—

Zn spinel ferrite powder, hexagonal ferrite powder, and metallic magnetism powder.

5. A noise rejection device according to claim 1, wherein the core is pillar-shaped.

6. A noise rejection device according to claim 1, wherein the first magnetic insulating material comprises at least one of Ni—

Zn spinel ferrite, Y type hexagonal ferrite, and Z type hexagonal ferrite.

7. A noise rejection device according to claim 1, wherein

the first magnetic insulating material comprises Ni—

Zn spinel ferrite, and

an Fe ratio is between about 46 mol % and about 49.5 mol % as Fe₂O₃.

8. A noise rejection device according to claim 1, wherein

the first magnetic insulating material comprises Ni—

Zn spinel ferrite, and

an Ni/Zn ratio is equal to or higher than about 1.

9. A noise rejection device according to claim 1, wherein

the first magnetic insulating material comprises Ni—

Zn spinel ferrite, and

an Ni/Zn ratio is equal to or higher than about 4.

10. A noise rejection device according to claim 1, wherein the resistance film comprises a film formed of metal comprising at least one of NiCu, NiCuP, NiP and NiCr.

11. A cellular phone including a noise rejection device according to claim 1.