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

• US 9,342,179 B2
• Filed: 08/28/2014
• Issued: 05/17/2016
• 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, Nagata, Tomohiko, Hori, Akio, Higashi, Yoshihiro
• Primary Examiner(s): Noori, Max
• Application Number:
  US14/471,226
• Publication Number:
  US 20150082917A1
• Time in Patent Office: 628 Days
• Field of Search: 738/626.9, 737/79
• US Class Current: 1/1
• 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
• CPC Class Codes: G06F 3/04144 using an array of force sensing means position sensing using the local deformation of sensor cells G06F3/0447
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 31/00 Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor manufacture of microstructural arrangements of deformable or non-deformable structures in general B81C1/00182

Abstract

According to one embodiment, a strain sensing element includes a film unit, and a sensing unit. The film unit has a film surface and is capable of being deformed. The sensing unit includes a first sensing element and a second sensing element. The first sensing element is provided between a part of the film unit and the second sensing element. The first sensing element includes a first magnetic layer having a changeable magnetization with a deformation of the film unit, a second magnetic layer provided apart from the first magnetic layer, and a first spacer layer provided between the first and second magnetic layers. The second sensing element includes a third magnetic layer having a changeable magnetization with the deformation of the film unit, a fourth magnetic layer provided apart from the third magnetic layer, and a second spacer layer provided between the third and fourth magnetic layers.

Claims

1. A strain sensing element comprising:

a film unit having a film surface and being deformable; and

a sensing unit including a first sensing element and a second sensing element,

the first sensing element being provided between a part of the film unit and the second sensing element,

the first sensing element including a first magnetic layer, a second magnetic layer provided apart from the first magnetic layer in a first direction crossing the film surface, and a first spacer layer provided between the first magnetic layer and the second magnetic layer, a magnetization of the first magnetic layer being configured to change in accordance with a deformation of the film unit,

the second sensing element including a third magnetic layer, a fourth magnetic layer provided apart from the third magnetic layer in the first direction, and a second spacer layer provided between the third magnetic layer and the fourth magnetic layer, a magnetization of the third magnetic layer being configured to change in accordance with the deformation of the film unit,

wherein

a magnetization of the second magnetic layer and a magnetization of the fourth magnetic layer are fixed,

the fourth magnetic layer is disposed between the third magnetic layer and the film unit, and

the second magnetic layer is disposed between the first magnetic layer and the film unit.

2. The element according to claim 1, further comprising:

a first electrode; and

a second electrode,

the sensing unit being provided between the first electrode and the second electrode,

a current flowing between the first electrode and the second electrode being configured to flow between the first magnetic layer and the second magnetic layer, and

the current being configured to flow between the third magnetic layer and the fourth magnetic layer.

3. A pressure sensor comprising:

the strain sensing element according to claim 1; and

a support supporting the film unit.

5. A microphone comprising the pressure sensor according to claim 3.

7. The element according to claim 1, wherein

the third magnetic layer is disposed between the fourth magnetic layer and the film unit, and

the second magnetic layer is disposed between the first magnetic layer and the film unit.

8. The element according to claim 1, wherein a distance between the first magnetic layer and the third magnetic layer is not more than ⅕

of a thickness along the first direction of the film unit.

9. The element according to claim 1, wherein the sensing unit further includes a first hard bias layer arranged with the first sensing element in a second direction crossing the first direction.

10. The element according to claim 1, wherein the sensing unit further includes a first shield layer arranged with the first sensing element in a second direction crossing the first direction.

11. The element according to claim 1, wherein the sensing unit further includes a second shield layer provided between the first sensing element and the second sensing element.

12. The element according to claim 1, wherein the sensing unit further includes an interposition layer provided between the first sensing element and the second sensing element.

13. The element according to claim 1, wherein

the sensing unit is provided in a plurality,

the plurality of sensing units are provided on the film unit, and

the sensing units are apart from each other in a direction crossing the first direction.

14. The element according to claim 13, wherein the sensing units are electrically connected in series.

15. The element according to claim 13, wherein the sensing units are electrically connected in parallel.

16. The element according to claim 13, wherein

the sensing units are electrically connected to one another and

a number of the sensing units electrically connected is not less than 7 and not more than 200.

17. A blood pressure sensor comprising the pressure sensor according to claim 3.

18. A touch panel comprising the pressure sensor according to claim 3.

4. A strain sensing element comprising:

a film unit having a film surface and being deformable; and

a sensing unit including a first sensing element and a second sensing element,

the first sensing element being provided between a part of the film unit and the second sensing element,

the first sensing element including a first magnetic layer, a second magnetic layer provided apart from the first magnetic layer in a first direction crossing the film surface, and a first spacer layer provided between the first magnetic layer and the second magnetic layer, a magnetization of the first magnetic layer being configured to change in accordance with a deformation of the film unit,

the second sensing element including a third magnetic layer, a fourth magnetic layer provided apart from the third magnetic layer in the first direction, and a second spacer layer provided between the third magnetic layer and the fourth magnetic layer, a magnetization of the third magnetic layer being configured to change in accordance with the deformation of the film unit,

wherein

a magnetization of the second magnetic layer and a magnetization of the fourth magnetic layer are fixed,

the third magnetic layer is disposed between the fourth magnetic layer and the film unit, and

the first magnetic layer is disposed between the second magnetic layer and the film unit.

6. A strain sensing element comprising:

a film unit having a film surface and being deformable; and

a sensing unit including a first sensing element and a second sensing element,

the first sensing element being provided between a part of the film unit and the second sensing element,

the first sensing element including a first magnetic layer, a second magnetic layer provided apart from the first magnetic layer in a first direction crossing the film surface, and a first spacer layer provided between the first magnetic layer and the second magnetic layer, a magnetization of the first magnetic layer being configured to change in accordance with a deformation of the film unit,

the second sensing element including a third magnetic layer, a fourth magnetic layer provided apart from the third magnetic layer in the first direction, and a second spacer layer provided between the third magnetic layer and the fourth magnetic layer, a magnetization of the third magnetic layer being configured to change in accordance with the deformation of the film unit,

wherein

a magnetization of the second magnetic layer and a magnetization of the fourth magnetic layer are fixed,

the fourth magnetic layer is disposed between the third magnetic layer and the film unit, and

the first magnetic layer is disposed between the second magnetic layer and the film unit.