Multilayer inductor

• US 6,535,094 B2
• Filed: 03/15/2001
• Issued: 03/18/2003
• Est. Priority Date: 03/15/2000
• Status: Expired due to Fees

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Murata, Satoshi, Tamada, Minoru, Mihara, Hideyuki, Yamamoto, Etsuji, Nishinaga, Yoshihiro
• Primary Examiner(s): Enad, Elvin
• Assistant Examiner(s): Nguyen, Tuyen T.
• Application Number:
  US09/808,668
• Publication Number:
  US 20010033218A1
• Time in Patent Office: 733 Days
• Field of Search: 331/65, 331/83, 331/198, 331/192, 331/200, 331/208, 331/207, 331/206, 331/232, 296/021, 296/05, 296/06
• US Class Current: 336/83
• CPC Class Codes: H01F 17/0033 with the coil helically wound around a magnetic core

Abstract

Three thin-film coils having insulating layers therebetween are laminated on the coil winding portion of the core member. A terminal electrode is electrically connected to the end portion of the third thin-film coil. A terminal electrode is electrically connected to the end portion of the first thin-film coil through the lead-out opening portions and separated areas. In this way, the thin-film coils are electrically connected in series between the terminal electrodes. Then, in the thin-film coils, the winding directions of the neighboring coils having an insulating layer therebetween are opposite to each other.

Claims

1. A multilayer inductor comprising:

a core member;

a plurality of thin-film coils laminated on the surface of the core member and having a spirally wound arrangement, each of said plurality of thin film coils being defined by a layer;

insulating layers provided between each of said plurality of thin-film coils; and

terminal electrodes provided at end portions of the core member;

wherein the winding directions of the adjacent thin-film coils having said insulating layers therebetween are opposite to each other;

the plurality of the thin-film coils are electrically connected in series; and

at least one of the layers defining said plurality of thin-film coils includes a separated area which is separated from the respective thin-film coil by a separating groove.

2. A multilayer inductor as claimed in claim 1, further comprising first separating portions for electrically connecting the thin-film coils in series, said first separating portions arranged between an area where the thin-film coils are provided and the areas where the terminal electrodes are provided to surround the periphery of the core member,

wherein the adjacent thin-film coils having the insulating layers therebetween are electrically connected in series through an opening portion in the insulating layers for connecting the thin-film coils provided.

3. A multilayer inductor as claimed in claim 2, wherein at least one of the beginning and the end of a coil including the plurality of thin-film coils electrically connected in series is electrically connected to the terminal electrode through lead-out opening portions provided in the insulating layers.

4. A multilayer inductor as claimed in claim 2, further comprising second separating portions to form separated areas electrically disconnected from the thin-film coils below the terminal electrodes, said second separating portions arranged between the area where the thin-film coils are provided and the areas where the terminal electrodes are provided to surround the periphery of the core member.

5. A multilayer inductor as claimed in claim 4, wherein at least one of the beginning and the end of a coil including the plurality of thin-film coils electrically connected in series is electrically connected to the terminal electrode through lead-out opening portions provided in the insulating layers.

6. A multilayer inductor as claimed in claim 1, wherein the core member is dumbbell-shaped.

7. A multilayer inductor as claimed in claim 1, wherein an identification portion for identifying the direction of the core member is provided on at least one of an end face and a side face of the core member.

8. A multilayer inductor as claimed in claim 1, wherein said plurality of thin-film coils includes three thin-film coils.

9. A multilayer inductor as claimed in claim 3, wherein said lead-out opening portions provided in the insulating layers are defined by single straight lines.

10. A multilayer inductor as claimed in claim 1, wherein said core is made of Ni—

Zn—

Cu ferrite.