Flexible inductor

Patent metadata

Field	Value
Publication number	US-11424062-B2
Application number	US-201815863546-A
Country	US
Kind code	B2
Filing date	Jan 5, 2018
Priority date	Jul 24, 2015
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

A flexible inductor mounted on a flexible substrate can be deformed while following deflection of the flexible substrate over time, and has high resistance to drop impact. The flexible inductor includes a coil substrate having a spiral conductor on at least one of upper and lower surfaces, and first and second magnetic sheets laminated on the upper and lower surfaces, respectively. First and second outer electrodes are provided in a peripheral edge portion of the lower surface. The first and second electrodes make direct contact with the lower surface, and are electrically connected to outermost and innermost end portions, respectively, of the spiral conductor. The second magnetic sheet is laminated on the lower surface other than portions corresponding to the first and second outer electrodes. Thicknesses of the first and second outer electrodes are equal to or larger than a thickness of the second magnetic sheet.

First claim

What is claimed is:

1. A flexible inductor comprising:
a coil substrate having a spiral conductor on at least one of an upper surface and a lower surface; and
a first magnetic sheet laminated on the upper surface of the coil substrate and a second magnetic sheet laminated on the lower surface of the coil substrate,
a first outer electrode that makes direct contact with the lower surface of the coil substrate and is electrically connected to an outermost end portion of the spiral conductor, and a second outer electrode that makes direct contact with the lower surface of the coil substrate and is electrically connected to an innermost end portion of the spiral conductor, are provided in a peripheral edge portion of the lower surface of the coil substrate and the second magnetic sheet is laminated on the lower surface of the coil substrate other than portions corresponding to the first outer electrode and the second outer electrode, the first outer electrode and the second outer electrode each including a plurality of columnar conductors and a hat-like conductor formed on a top of each columnar conductor to connect each respective plurality of columnar conductors,
thicknesses of the first outer electrode and the second outer electrode are equal to a thickness of the second magnetic sheet or are larger than the thickness of the second magnetic sheet, and
in the coil substrate, a center portion of a flexible board is removed to form a cavity, and
the first magnetic sheet and the second magnetic sheet are bonded to each other in the cavity via at least one adhesive sheet.

2. The flexible inductor according to claim 1 , wherein
the coil substrate has one or a plurality of cutout portions in the vicinity of at least one of the first outer electrode and the second outer electrode.

3. The flexible inductor according to claim 1 , wherein:
the coil substrate has a square lower surface, the first outer electrode, the second outer electrode, a third outer electrode that makes direct contact with the lower surface of the coil substrate and is not connected to the spiral conductor, and a fourth outer electrode that makes direct contact with the lower surface of the coil substrate and is not connected to the spiral conductor are provided at four corners of the lower surface of the coil substrate;
the second magnetic sheet is laminated on the lower surface of the coil substrate other than portions corresponding to the first outer electrode, the second outer electrode, the third outer electrode, and the fourth outer electrode; and
thicknesses of the first outer electrode, the second outer electrode, the third outer electrode, and the fourth outer electrode are equal to the thickness of the second magnetic sheet or are larger than the thickness of the second magnetic sheet.

4. The flexible inductor according to claim 3 , wherein
the coil substrate has one or a plurality of cutout portions in the vicinity of at least one of the third outer electrode and the fourth outer electrode.

5. The flexible inductor according to claim 2 , wherein:
the coil substrate has a square lower surface, the first outer electrode, the second outer electrode, a third outer electrode that makes direct contact with the lower surface of the coil substrate and is not connected to the spiral conductor, and a fourth outer electrode that makes direct contact with the lower surface of the coil substrate and is not connected to the spiral conductor are provided at four corners of the lower surface of the coil substrate;
the second magnetic sheet is laminated on the lower surface of the coil substrate other than portions corresponding to the first outer electrode, the second outer electrode, the third outer electrode, and the fourth outer electrode; and
thicknesses of the first outer electrode, the second outer electrode, the third outer electrode, and the fourth outer electrode are equal to the thickness of the second magnetic sheet or are larger than the thickness of the second magnetic sheet.

6. A method for manufacturing a flexible inductor which includes a coil substrate having a spiral conductor on at least one of an upper surface and a lower surface, and a first magnetic sheet laminated on the upper surface of the coil substrate and a second magnetic sheet laminated on the lower surface of the coil substrate, the method comprising:
forming a first outer electrode that makes direct contact with the lower surface of the coil substrate and is electrically connected to an outermost end portion of the spiral conductor and a second outer electrode that makes direct contact with the lower surface of the coil substrate and is electrically connected to an innermost end portion of the spiral conductor in a peripheral edge portion of the lower surface of the coil substrate, the first outer electrode and the second outer electrode each including a plurality of columnar conductors and a hat-like conductor formed on a top of each columnar conductor to connect each respective plurality of columnar conductors; and
laminating the second magnetic sheet on the lower surface of the coil substrate other than portions corresponding to the first outer electrode and the second outer electrode so as to have a thickness that is equal to thicknesses of the first outer electrode and the second outer electrode or is smaller than the thicknesses of the first outer electrode and the second outer electrode, wherein
in the coil substrate, a center portion of a flexible board is removed to form a cavity, and
the first magnetic sheet and the second magnetic sheet are bonded to each other in the cavity via at least one adhesive sheet.

7. A flexible inductor comprising:
a coil substrate having a spiral conductor on at least one of an upper surface and a lower surface; and
a first magnetic sheet laminated on the upper surface of the coil substrate and a second magnetic sheet laminated on the lower surface of the coil substrate, wherein
a first outer electrode that makes direct contact with the lower surface of the coil substrate and is electrically connected to an outermost end portion of the spiral conductor, and a second outer electrode that makes direct contact with the lower surface of the coil substrate and is electrically connected to an innermost end portion of the spiral conductor, are provided in a peripheral edge portion of the lower surface of the coil substrate and the second magnetic sheet is laminated on the lower surface of the coil substrate other than portions corresponding to the first outer electrode and the second outer electrode, the first outer electrode and the second outer electrode each including a plurality of columnar conductors and a hat-like conductor formed on a top of each columnar conductor to connect each respective plurality of columnar conductors,
thicknesses of the first outer electrode and the second outer electrode are equal to a thickness of the second magnetic sheet or are larger than the thickness of the second magnetic sheet,
in the coil substrate, a center portion of a flexible board is removed to form a cavity, and
the first magnetic sheet and the second magnetic sheet are directly bonded to each other in the cavity.

8. A method for manufacturing a flexible inductor which includes a coil substrate having a spiral conductor on at least one of an upper surface and a lower surface, and a first magnetic sheet laminated on the upper surface of the coil substrate and a second magnetic sheet laminated on the lower surface of the coil substrate, the method comprising:
forming a first outer electrode that makes direct contact with the lower surface of the coil substrate and is electrically connected to an outermost end portion of the spiral conductor and a second outer electrode that mak

Assignees

• Murata Manufacturing Co

Inventors

• Yamaguchi Koichi

Classifications

• H01F27/245 Primary

  made from sheets, e.g. grain-oriented (H01F27/26 takes precedence) · CPC title

• H01F17/0013

  with stacked layers · CPC title

• H01F2017/006

  flexible printed inductors · CPC title

• H01F41/10

  Connecting leads to windings (making electric connections in general H01R43/00) · CPC title

• H01F27/292

  Surface mounted devices · CPC title