Strain sensing element, pressure sensor, microphone, blood pressure sensor, and touch panel

• US 9,872,624 B2
• Filed: 08/28/2014
• Issued: 01/23/2018
• Est. Priority Date: 09/20/2013
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Fuji, Yoshihiko, Fukuzawa, Hideaki, Kaji, Shiori, Hori, Akio, Nagata, Tomohiko, Hara, Michiko, Higashi, Yoshihiro, Yuzawa, Akiko
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): Kidanu, Gedeon M
• Application Number:
  US14/471,694
• Publication Number:
  US 20150082918A1
• Time in Patent Office: 1,244 Days
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/02141 Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits A61B5/02233, A61B5/0235 take precedence
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: G01L 1/125 by using magnetostrictive means magnetostrictive sensors H10N35/101
• CPC Class Codes: G01L 9/0041 Transmitting or indicating the displacement of flexible diaphragms
• CPC Class Codes: G01L 9/16 by making use of variations in the magnetic properties of material resulting from the application of stress

Abstract

According to one embodiment, a strain sensing element is provided on a film unit configured to be deformed. The strain sensing element includes a functional layer, a first magnetic layer, a second magnetic layer, and a spacer layer. The functional layer includes at least one of an oxide and a nitride. The second magnetic layer is provided between the functional layer and the first magnetic layer. A magnetization of the second magnetic layer is variable in accordance with a deformation of the film unit. The spacer layer is provided between the first magnetic layer and the second magnetic layer. At least a part of the second magnetic layer is amorphous and includes boron.

Claims

1. A strain sensing element provided on a film being deformable, the strain sensing element comprising:

a non-magnetic layer;

a first magnetic layer;

a functional layer provided between the non-magnetic layer and the first magnetic layer, the functional layer contacting the non-magnetic layer, the functional layer including at least one selected from the group consisting of an oxide and a nitride;

a second magnetic layer provided between the functional layer and the first magnetic layer, a magnetization of the second magnetic layer being variable in accordance with a deformation of the film; and

a spacer layer provided between the first magnetic layer and the second magnetic layer,

at least a part of the second magnetic layer being amorphous and including boron.

2. The element according to claim 1, wherein

the oxide includes an oxide of at least one selected from the group consisting of magnesium, aluminum, silicon, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, hafnium, tantalum, tungsten, tin, cadmium, and gallium, and

the nitride includes a nitride of at least one selected from the group consisting of magnesium, aluminum, silicon, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, hafnium, tantalum, tungsten, tin, cadmium, and gallium.

3. The element according to claim 1, wherein the functional layer includes an oxide of at least one selected from the group consisting of magnesium, titanium, vanadium, zinc, tin, cadmium, and gallium.

4. The element according to claim 1, wherein the functional layer includes magnesium oxide.

5. The element according to claim 1, wherein a thickness of the functional layer is not more than one nanometer.

6. The element according to claim 1, wherein a concentration of boron included in the functional layer is not less than 5 atomic percent and not more than 35 atomic percent.

7. The element according to claim 1, wherein

the second magnetic layer includes a first portion and a second portion,

the first portion is provided between the second portion and the spacer layer, and

a concentration of boron in the first portion is lower than a concentration of boron in the second portion.

8. The element according to claim 1, wherein

the second magnetic layer includes a first portion and a second portion,

the first portion is provided between the second portion and the spacer layer, and

the first portion has crystallinity.

9. The element according to claim 1, wherein a magnetostriction constant of the second magnetic layer is not less than 1×

10<sup>−

5</sup>.

10. The element according to claim 1, wherein a coercivity of the second magnetic layer is not more than 5 oersteds.

11. The element according to claim 1, wherein a sheet resistivity of the functional layer is lower than a sheet resistivity of the spacer layer.

12. A pressure sensor comprising:

a film being deformable; and

a strain sensing element provided on the film, the strain sensing element including;

a non-magnetic layer;

a first magnetic layer;

a functional layer provided between the non-magnetic layer and the first magnetic layer, the functional layer contacting the non-magnetic layer, the functional layer including at least one selected from the group consisting of an oxide and a nitride;

a second magnetic layer provided between the functional layer and the first magnetic layer, a magnetization of the second magnetic layer being variable in accordance with a deformation of the film; and

a spacer layer provided between the first magnetic layer and the second magnetic layer,

at least a part of the second magnetic layer being amorphous and including boron.

13. The sensor according to claim 12, wherein the strain sensing element is provided in a plurality.

14. The sensor according to claim 12, wherein at least two of the plurality of strain sensing elements are electrically connected in series.

15. The sensor according to claim 14, wherein a voltage of not less than 1 V and not more than 10 V is applied between terminals of the strain sensing elements electrically connected in series.

16. The sensor according to claim 14, wherein a number of strain sensing elements electrically connected in series is not less than 6 and not more than 200.

17. A strain sensing element provided on a film being deformable, the strain sensing element comprising:

a non-magnetic layer;

a first magnetic layer;

a functional layer provided between the non-magnetic layer and the first magnetic layer, the functional layer contacting the non-magnetic layer, the functional layer including at least one element selected from the group consisting of magnesium, silicon, and aluminum;

a second magnetic layer provided between the functional layer and the first magnetic layer, a magnetization of the second magnetic layer being variable in accordance with a deformation of the film; and

a spacer layer provided between the first magnetic layer and the second magnetic layer,

at least a part of the second magnetic layer being amorphous and including boron.

18. A microphone comprising:

a pressure sensor, the pressure sensor including;

a film being deformable; and

a strain sensing element provided on the film, the strain sensing element including;

a non-magnetic layer;

a first magnetic layer;

a functional layer provided between the non-magnetic layer and the first magnetic layer, the functional layer contacting the non-magnetic layer, the functional layer including at least one selected from the group consisting of an oxide and a nitride;

a second magnetic layer provided between the functional layer and the first magnetic layer, a magnetization of the second magnetic layer being variable in accordance with a deformation of the film; and

a spacer layer provided between the first magnetic layer and the second magnetic layer,

at least a part of the second magnetic layer being amorphous and including boron.

19. A blood pressure sensor comprising:

a pressure sensor, the pressure sensor including;

a film being deformable; and

a strain sensing element provided on the film, the strain sensing element including;

a non-magnetic layer;

a first magnetic layer;

a functional layer provided between the non-magnetic layer and the first magnetic layer, the functional layer contacting the non-magnetic layer, the functional layer including at least one selected from the group consisting of an oxide and a nitride;

a second magnetic layer provided between the functional layer and the first magnetic layer, a magnetization of the second magnetic layer being variable in accordance with a deformation of the film; and

a spacer layer provided between the first magnetic layer and the second magnetic layer,

at least a part of the second magnetic layer being amorphous and including boron.

20. A touch panel comprising:

a pressure sensor, the pressure sensor including;

a film being deformable; and

a strain sensing element provided on the film, the strain sensing element including;

a non-magnetic layer;

a first magnetic layer;

a functional layer provided between the non-magnetic layer and the first magnetic layer, the functional layer contacting the non-magnetic layer, the functional layer including at least one selected from the group consisting of an oxide and a nitride;

a second magnetic layer provided between the functional layer and the first magnetic layer, a magnetization of the second magnetic layer being variable in accordance with a deformation of the film; and

a spacer layer provided between the first magnetic layer and the second magnetic layer,

at least a part of the second magnetic layer being amorphous and including boron.