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

• US 9,654,883 B2
• Filed: 09/03/2014
• Issued: 05/16/2017
• 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
• Primary Examiner(s): Patel, Harshad R
• Assistant Examiner(s): HOPKINS, BRANDI N
• Application Number:
  US14/476,200
• Publication Number:
  US 20150082901A1
• Time in Patent Office: 986 Days
• Field of Search: 73779, 7386269, 73725, 73754, 73726
• 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: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 2201/06 Bio-MEMS
• CPC Class Codes: B81B 3/0078 Constitution or structural means for improving mechanical properties not provided for in B81B3/007 - B81B3/0075
• 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 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 2201/003 Mems transducers or their use of the electrostatic type H04R19/005
• CPC Class Codes: H04R 23/00 Transducers other than those covered by groups H04R9/00 - H04R21/00 diaphragms for transducers of the distributed-mode type H04R7/045
• CPC Class Codes: H04R 23/006 using solid state devices solid state devices per se H01L
• CPC Class Codes: H04R 2410/03 Reduction of intrinsic noise in microphones
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones
• CPC Class Codes: H04R 31/006 Interconnection of transducer parts of diaphragm and outer suspension by moulding H04R31/003

Abstract

According to one embodiment, a strain sensing element provided on a deformable substrate includes: a first magnetic layer; a second magnetic layer; a spacer layer; and a bias layer. Magnetization of the second magnetic layer changes according to deformation of the substrate. The spacer layer is provided between the first magnetic layer and the second magnetic layer. The second magnetic layer is provided between the spacer layer and the bias layer. The bias layer is configured to apply a bias to the second magnetic layer.

Claims

1. A strain sensing element provided on a deformable substrate, comprising:

a first layer having a first magnetization;

a second layer having a second magnetization to change according to a deformation of the substrate;

an intermediate layer provided between the first layer and the second layer; and

a third layer,

the second layer being provided between the intermediate layer and the third layer,

the third layer including at least one of a first material or a second material,

the first material including at least one selected from the group consisting of Ir—

Mn, Pt—

Mn, Pd—

Pt—

Mn, and Ru—

Rh—

Mn, and

the second material including at least one selected from the group consisting of CoPt (a ratio of Co being not less than 50 at. % and not more than 85 at. %), (Co_xPt_100-x)_100-yCr_y (x being not less than 50 at. % and not more than 85 at. %, and y being not less than 0 at. % and not more than 40 at. %), and FePt (a ratio of Pt being not less than 40 at. % and not more than 60 at. %).

2. The element according to claim 1, wherein the first magnetization is pinned.

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

a fourth layer provided between the third layer and the second layer, the fourth layer being magnetic; and

a fifth layer provided between the fourth layer and the second layer, the fifth layer being non-magnetic.

4. The element according to claim 3, wherein

the fourth layer includes at least one selected from the group consisting of Co, Fe, and Ni, and

the fifth layer includes at least one selected from the group consisting of Cu, Ru, Rh, Ir, V, Cr, Nb, Mo, Ta, W, Rr, Au, Ag, Pt, Pd, Ti, Zr, and Hf.

5. The element according to claim 3, further comprising:

a sixth layer provided between the third layer and the fourth layer;

a seventh layer provided between the sixth layer and the fourth layer; and

a relative angle between a magnetization of the fourth layer and a magnetization of the sixth layer is 180°

.

6. The element according to claim 3, wherein the fifth layer includes at least one selected from the group consisting of copper (Cu), gold (Au), silver (Ag), chrome (Cr), ruthenium (Ru), and iridium (Ir).

7. The element according to claim 1, wherein the third layer applies a magnetic bias to the second layer, and a relative angle between a direction of the magnetic bias in the second layer and the first magnetization is 180°

.

8. The element according to claim 1, wherein the third layer applies a magnetic bias to the second layer, and a relative angle between a direction of the magnetic bias in the second layer and the first magnetization is not less than 90°

and not more than 270°

.

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

10. The element according to claim 1, wherein at least one of at least a part of the first layer or at least a part of the second layer is amorphous.

11. The element according to claim 1, wherein at least one of the first layer or the second layer includes boron.

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

an eighth layer,

the first layer being provided between the eighth layer and the intermediate layer,

the first magnetization being configured to change according to a deformation,

the eight layer including at least one of a third material or a fourth material,

the third material including at least one selected from the group consisting of Ir—

Mn, Pt—

Mn, Pd—

Pt—

Mn, and Ru—

Rh—

Mn, and

the fourth material including at least one selected from the group consisting CoPt (a ratio of Co being not less than 50 at. % and not more than 85 at. %), (Co_xPt_100-x)_100-yCr_y (x being not less than 50 at. % and not more than 85 at. %, and y being not less than 0 at. % and not more than 40 at. %), and FePt (a ratio of Pt being not less than 40 at. % and not more than 60 at. %).

13. The element according to claim 12, further comprising:

a ninth layer provided between the eighth layer and the first layer, the ninth layer being magnetic; and

a tenth layer provided between the ninth layer and the first layer, the tenth layer being non-magnetic.

14. The element according to claim 13, wherein

the ninth layer includes at least one selected from the group consisting of Co, Fe, and Ni, and

the tenth layer includes at least one selected from the group consisting of Cu, Ru, Rh, Ir, V, Cr, Nb, Mo, Ta, W, Rr, Au, Ag, Pt, Pd, Ti, Zr, and Hf.

15. The element according to claim 13, further comprising:

an eleventh layer provided between the eighth layer and the ninth layer;

a twelfth layer provided between the eleventh layer and the eighth layer; and

a relative angle between a magnetization of the ninth layer and a magnetization of the eleventh layer is 180°

.

16. The element according to claim 15, further comprising:

a lower first magnetic coupling layer provided between the lower first bias magnetic layer and the lower second bias magnetic layer and configured to cause anti-ferromagnetic coupling to occur between the lower first bias magnetic layer and the lower second bias magnetic layer,

wherein the third layer applies a first magnetic bias to the second layer,

the eighth layer applies a second magnetic bias to the first layer, and

a relative angle between a direction of the first magnetic bias in the second layer and a direction of the second magnetic bias in the first layer is 180°

.

17. The element according to claim 13, wherein

the tenth layer includes at least one selected from the group consisting of copper (Cu), gold (Au), silver (Ag), chrome (Cr), ruthenium (Ru), and iridium (Ir).

18. The element according to claim 12, wherein

the third layer applies a first magnetic bias to the second layer,

the eight layer applies a second magnetic bias to the first layer, and

a relative angle between a direction of the first magnetic bias in the second layer and a direction of the second magnetic bias in the first layer is 180°

.

19. The element according to claim 12, wherein

a coercivity of the first layer is not more than 10 Oe, and

a coercivity of the second layer is not more than 10 Oe.

20. The element according to claim 12, wherein

at least one of at least a part of the first layer or at least a part of the second layer is amorphous.

21. The element according to claim 12, wherein

at least one of the first layer or the second layer includes boron.

22. A pressure sensor comprising:

a support unit;

a substrate supported by the support unit, the substrate being deformable; and

a strain sensing element provided on the substrate, the strain sensing element including

a first layer having a first magnetization,

a second layer having a second magnetization to change according to a deformation of the substrate,

an intermediate layer provided between the first layer and the second layer, and

a third layer,

the second layer being provided between the intermediate layer and the third layer,

the third layer including at least one of a first material or a second material,

the first material including at least one selected from the group consisting of Ir—

Mn, Pt—

Mn, Pd—

Pt—

Mn, and Ru—

Rh—

Mn, and

the second material including at least one selected from the group consisting CoPt (a ratio of Co being not less than 50 at. % and not more than 85 at. %), (Co_xPt_100-x)_100-xCr_y (x being not less than 50 at. % and not more than 85 at. %, and y being not less than 0 at. % and not more than 40 at. %), and FePt (a ratio of Pt being not less than 40 at. % and not more than 60 at %).

23. The sensor according to claim 22, wherein the strain sensing element further includes:

a fourth layer provided between the third layer and the second layer, the fourth layer being magnetic, and

a fifth layer provided between the fourth layer and the second layer, the fifth layer being non-magnetic, and

a first angle formed by a magnetization of the fourth layer and a first straight line is in a first range or a second range,

the first range is not less than 0° and

not more than 15°

,

the second range is not less than 75° and

not more than 105°

, and

the first straight line connects an outer edge of the substrate and a centroid of the strain sensing element in shortest distance.

24. The sensor according to claim 22, wherein the strain sensing element further includes:

a fourth layer provided between the third layer and the second layer, the fourth layer being magnetic, and

a fifth layer provided between the fourth layer and the second layer, the fifth layer being non-magnetic, and

a second angle formed by a magnetization of the fourth layer and a second straight line is in a first range or a second range,

the first range is not less than 0° and

not more than 15°

,

the second range is not less than 75° and

not more than 105°

, and

the second straight line connects a centroid of the substrate and a centroid of the strain sensing element in shortest distance.

25. The sensor according to claim 22, wherein a plurality of strain sensing elements are provided on the substrate.

26. The sensor according to claim 25, wherein at least two of the plurality of strain sensing elements are electrically connected in series.

27. The sensor according to claim 26, wherein a voltage applied between terminals of the plurality of strain sensing elements that are electrically connected in series is not less than 1 V and not more than 10 V.

28. The sensor according to claim 26, wherein the number of the plurality of strain sensing elements that are electrically connected in series is not less than 6 and not more than 200.

29. A microphone, comprising:

a cover; and

the pressure sensor according to claim 22, the pressure sensor being provided in the cover.

30. A blood pressure sensor including the pressure sensor according to claim 22.

31. A touch panel, comprising:

a first interconnect;

a second interconnect; and

the pressure sensor according to claim 22,

the pressure sensor being provided at an intersection between the first interconnect and the second interconnect.