Mechanical sensor having a U-shaped planar coil and a magnetic layer

• US 5,450,755 A
• Filed: 10/19/1993
• Issued: 09/19/1995
• Est. Priority Date: 10/21/1992
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Saito, Shinji, Hase, Hiroyuki
• Primary Examiner(s): CHILCOT, RICHARD E
• Assistant Examiner(s): Olsen, James M.
• Application Number:
  US08/138,744
• Time in Patent Office: 700 Days
• Field of Search: 73/763, 73/760, 73/781, 73/855, 73/777, 73/779, 328/1
• US Class Current: 73/763
• CPC Class Codes: G01L 1/125 by using magnetostrictive means magnetostrictive sensors H10N35/101
• CPC Class Codes: G01L 1/127 by using inductive means G01L1/122, G01L1/125 take precedence
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01F 2017/0073 with a special conductive pattern, e.g. flat spiral

Abstract

A mechanical sensor is provided, which includes: a magnetic layer having permeability which is changed in accordance with stress generated therein; a coil having at least two terminals, allowing an electric current to flow therebetween to generate a magnetic flux, thereby magnetizing the magnetic layer; and a substrate integrally supporting the magnetic layer and the coil, wherein the coil is a planar coil including at least one winding, each winding having a U-shaped portion formed of a first conductive line portion, a second conductive line portion, and a connecting portion connecting the first and second conductive line portions, the first and second conductive line portions extending in a first direction, and impedance between the terminals is changed in accordance with a change of inductance caused by a change of the permeability of the magnetic layer.

Claims

1. A mechanical sensor comprising:

a magnetic layer having permeability which is changed in accordance with stress generated therein,

a coil having at least two terminals, allowing an electric current to flow therebetween to generate a magnetic flux, thereby magnetizing the magnetic layer; and

a substrate integrally supporting the magnetic layer and the coil,

wherein the coil is a planar coil including at least one winding, each winding having a U-shaped portion formed of a first conductive line portion, a second conductive line portion, and a connecting portion connecting the first and second conductive line portions, the first and second conductive line portions extending in a first direction and magnetizing the magnetic layer in a direction which is substantially perpendicular to the first direction and is parallel to a surface of said magnetic layer, and an impedance between the terminals is changed in accordance with a change of inductance caused by a change of the permeability of the magnetic layer.

2. A mechanical sensor according to claim 1, wherein the coil is a planar coil including at least two windings, and a distance between conductive line portions in which an electric current flows in the same direction is smaller than a distance between conductive line portions in which an electric current flows in the opposite directions to each other.

3. A mechanical sensor according to claim 1, wherein the coil is formed on an insulator layer supported by the substrate.

4. A mechanical sensor according to claim 3, wherein the magnetic layer is formed between the insulator layer and the substrate.

5. A mechanical sensor according to claim 3, wherein the magnetic layer is formed on the coil with another insulator layer formed therebetween.

6. A mechanical sensor according to claim 1, wherein the magnetic layer has a two-layered structure and sandwiches the coil.

7. A mechanical sensor comprising:

a magnetic layer having permeability which is changed in accordance with stress generated therein,

a coil having at least two terminals, allowing an electric current to flow therebetween to generate a magnetic flux, thereby magnetizing the magnetic layer; and

a substrate integrally supporting the magnetic layer and the coil,

wherein the coil is a planar coil including at least one winding, each winding having a first U-shaped portion formed of a first conductive line portion, a second conductive line portion, and a connecting portion connecting the first and second conductive line portions, and having a second U-shaped portion formed of a third conductive line portion, a fourth conductive line portion, and a connecting portion connecting the third and fourth conductive line portions, the first, second, third, and fourth conductive line portions extending in a first direction and magnetizing the magnetic layer in a direction which is substantially perpendicular to the first direction and is parallel to a surface of said magnetic layer; and

wherein the first and second U-shaped portions are connected in series between the terminals, and an impedance between the terminals is changed in accordance with a change of inductance caused by a change of the permeability of the magnetic layer.

8. A mechanical sensor according to claim 7, wherein the coil is a planar coil including at least two windings, and a distance between conductive line portions in which an electric current flows in the same direction is smaller than a distance between conductive line portions in which an electric current flows in the opposite directions to each other.

9. A mechanical sensor according to claim 7, wherein the coil is formed on an insulator layer supported by the substrate.

10. A mechanical sensor according to claim 9, wherein the magnetic layer is formed between the insulator layer and the substrate.

11. A mechanical sensor according to claim 9, wherein the magnetic layer is formed on the coil with another insulator layer formed therebetween.

12. A mechanical sensor according to claim 7, wherein the magnetic layer has a two-layered structure and sandwiches the coil.

13. A mechanical sensor comprising:

a magnetic layer having permeability which is changed in accordance with stress generated therein,

a coil having at least two terminals, allowing an electric current to flow therebetween to generate a magnetic flux, thereby magnetizing the magnetic layer; and

a substrate integrally supporting the magnetic layer and the coil,

wherein the coil is a planar coil including at least one winding, each winding having a U-shaped portion formed of a first conductive line portion, a second conductive line portion, and a connecting portion connecting the first and second conductive line portions, the first and second conductive line portions extending in a first direction and magnetizing the magnetic layer in a direction which is substantially perpendicular to the first direction and is parallel to a surface of said magnetic layer, and an impedance between the terminals is changed in accordance with a change of inductance caused by a change of the permeability of the magnetic layer,

and wherein said magnetic layer does not extend into said connecting portion regions.