JP2022118688A - Pressure sensor device and voltage receiving element - Google Patents

Abstract

To provide an optical sensor device that can detect pressure in a narrow part and can be manufactured at low cost.SOLUTION: A pressure sensor device 1 has: a light emitting unit 10 that emits incident light; an optical fiber 80 that is optically connected with the light emitting unit 10; a pressure sensor 50 that is arranged at a leading end of the optical fiber 80, and when the incident light is incident thereon through the optical fiber 80, emits return light according to the pressure applied thereto; and a detection signal generating unit 60 that is optically connected with the pressure sensor 50 through the optical fiber 80, and based on the return light, outputs a detection signal according to the pressure applied to the pressure sensor 50. The pressure sensor 50 has a magnetic substance 55, a magnetic field sensor element 52 that is arranged in proximity to the magnetic substance 55, and when the incident light is incident, emits return light according to the magnetic field, and a pressure receiving element 54 that holds the magnetic substance 55 so that the distance between the magnetic field sensor element 52 and the magnetic substance 55 is changed according to the application of pressure.SELECTED DRAWING: Figure 4

Description

The present invention relates to pressure sensor devices and pressure receiving elements.

A Fabry-Perot resonator formed by a half mirror placed at the tip of an optical fiber and a reflective layer formed on the inner surface of a diaphragm is used to measure the pressure in a narrow space such as a patient's blood vessel. Sensor devices are known (see, for example, US Pat. In the pressure sensor devices described in Patent Documents 1 and 2, a Fabry-Perot resonator is placed at the tip of an extremely thin optical fiber with a diameter of 125 μm to reduce the physical burden on the patient, Pressure, such as blood pressure, can be measured in a confined space inside a patient's body.

JP 2005-291945 A Japanese Patent No. 5558580

However, it is not easy to manufacture a Fabry-Perot resonator so that the gap length between the half mirror and the reflective layer is uniform. Manufacturing costs may increase.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical sensor device that can detect pressure in a narrow space and that can be manufactured at low cost.

A pressure sensor device according to the present invention includes a light emitting portion that emits incident light, an optical fiber that is optically connected to the light emitting portion, and a tip of the optical fiber that receives the incident light through the optical fiber. Sometimes, a pressure sensor that emits return light corresponding to the applied pressure is optically connected to the pressure sensor via an optical fiber, and based on the return light, the pressure applied to the pressure sensor is detected. and a detection signal generator for outputting a signal, wherein the pressure sensor includes a magnetic material, and is arranged in proximity to the magnetic material, and emits return light corresponding to the magnetic field when incident light is incident thereon. and a pressure-receiving element that holds the magnetic body such that the distance between the magnetic field sensor element and the magnetic body changes according to the application of pressure.

Further, in the pressure sensor device according to the present invention, the pressure-receiving element has a cylindrical shape and has a base with an opening formed on one side surface, and is arranged inside the base and holds the magnetic body. It is preferable to have a supporting part and a spiral elastic part arranged on the other side surface of the base and having one end connected to the base and the other end connected to the supporting part.

Furthermore, in the pressure sensor device according to the present invention, the pressure receiving element is preferably made of silicon.

Furthermore, in the pressure sensor device according to the present invention, the elastic portion preferably has a water-repellent film formed on at least one of a first surface facing the magnetic field sensor element and a second surface opposite to the first surface.

Furthermore, in the pressure sensor device according to the present invention, it is preferable that the width of the elastic portion becomes narrower from one end connected to the base toward the other end connected to the support portion.

Furthermore, in the pressure sensor device according to the present invention, the groove is preferably formed so as to extend along a logarithmic spiral whose origin is the center of the bottom surface of the support.

Further, in the pressure sensor device according to the present invention, the elastic portion is formed with the first groove and the second groove, and the ends of the first groove and the second groove on the base side are arranged 180 degrees apart. , ends of the first groove and the second groove on the side of the support portion are preferably spaced apart by 180 degrees.

Further, in the pressure sensor device according to the present invention, the elastic portion is formed with the first groove, the second groove and the third groove, and the ends of the first groove, the second groove and the third groove on the base side are It is preferable that they are spaced apart by 120 degrees, and the ends of the first groove, the second groove, and the third groove on the side of the support portion are spaced apart by 120 degrees.

Furthermore, in the pressure sensor device according to the present invention, it is preferable that the pressure sensor further includes a second pressure receiving element that holds an end opposite to the end of the magnetic material held by the pressure receiving element.

Further, the pressure receiving element according to the present invention includes a base having a cylindrical shape and having an opening formed on one side surface, a supporting portion arranged inside the base and holding a magnetic body, and a base. and an elastic part disposed on the other side of the platform, one end of which is connected to the base and the other end of which is connected to the supporting part, and in which one or more spiral grooves are formed.

The pressure sensor device according to the present invention can detect pressure in a narrow space and can be manufactured at low cost.

1 is a block diagram showing a pressure sensor device according to an embodiment; FIG. FIG. 2 is an enlarged cross-sectional view of a portion indicated by a broken line A in FIG. 1; (a) is a perspective view (Part 1) of the pressure receiving element shown in FIG. 2, (b) is a perspective view (Part 2) of the pressure receiving element shown in FIG. 2, and (c) is a B- 4 is a perspective cross-sectional view of the pressure receiving element taken along line B; FIG. (a) is a diagram showing the pressure sensor in a state where pressure is not applied, and (b) is a diagram showing the pressure sensor in a state where pressure is applied. 3 is a diagram showing the relationship between the distance between the Faraday rotator and the magnetic material shown in FIG. 2 and the magnetic field applied to the Faraday rotator; FIG. (a) is a perspective view (part 1) of a pressure receiving element according to a first modification, (b) is a perspective view (part 2) of a pressure receiving element according to a first modification, and (c) is a first It is a front view of the pressure-receiving element which concerns on a modification. (a) is a perspective view (part 1) of a pressure receiving element according to a second modification, (b) is a perspective view (part 2) of a pressure receiving element according to a second modification, and (c) is a second It is a front view of the pressure-receiving element which concerns on a modification. (a) is a perspective view (part 1) of a pressure receiving element according to a third modification; (b) is a perspective view (part 2) of a pressure receiving element according to a third modification; It is a front view of the pressure-receiving element which concerns on a modification. (a) is a diagram showing the pressure sensor in a state where pressure is not applied, and (b) is a diagram showing the pressure sensor in a state where pressure is applied. 9A and 9B show the results of stress simulation of the pressure receiving element shown in FIG. von Mises stress generated in the elastic part. FIG. 11 is a partially enlarged cross-sectional view of a pressure sensor device according to a fourth modified example; FIG. 12 is a partially enlarged exploded sectional view of the pressure sensor device shown in FIG. 11; 12A is a plan view of the first pressure receiving element shown in FIG. 11, and FIG. 12B is a plan view of the second pressure receiving element shown in FIG. 11; FIG. 12A is a diagram showing the pressure sensor shown in FIG. 11 with no pressure applied; FIG. 12B is a diagram showing the pressure sensor shown in FIG. 11 with pressure applied; FIG. FIG. 11 is a plan view of a second pressure receiving element according to a modified example;

A pressure sensor device and a pressure receiving element according to the present invention will be described below with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to those embodiments, but extends to the invention described in the claims and equivalents thereof.

(Configuration and function of pressure sensor device according to embodiment)
FIG. 1 is a block diagram showing the pressure sensor device according to the embodiment.

The pressure sensor device 1 has a light emitting section 10 , a circulator 20 , a first optical element 30 , an optical path section 40 , a pressure sensor 50 and a detection signal generating section 60 . An optical path between the light emitting section 10 , the circulator 20 , the first optical element 30 , the optical path section 40 , the pressure sensor 50 and the detection signal generating section 60 is formed by a PANDA (Polarization-maintaining AND Absorption-reducing) fiber 80 . The outer diameter of the PAND fiber 80 is 125 μm in one example. The optical path between the first optical element 30, the optical path section 40, the pressure sensor 50, and the detection signal generating section 60 is a polarization maintaining type light beam such as a bow-tie fiber and an elliptical jacket fiber. It may be formed by fibers.

The light emitting section 10 has a light emitting element 11 , an isolator 12 and a polarizer 13 . The light emitting element 11 is, for example, a semiconductor laser or a light emitting diode. Specifically, a Fabry-Perot laser, a superluminescence diode, or the like can be preferably used as the light emitting element 11 .

The isolator 12 protects the light emitting element 11 by transmitting the light incident from the light emitting element 11 to the circulator 20 side and not transmitting the light incident from the circulator 20 to the light emitting element 11 side. The isolator 12 is, for example, a polarization dependent optical isolator, and may be a polarization independent optical isolator.

The polarizer 13 is an optical element for converting the light emitted by the light emitting element 11 into linearly polarized light, and its type is not particularly limited. The first linearly polarized light obtained by the polarizer 13 is incident on the first optical element 30 via the circulator 20 .

The circulator 20 transmits the first linearly polarized light emitted from the light emitting section 10 to the first optical element 30, and branches the second linearly polarized light emitted from the first optical element 30 to the detection signal generating section 60. It is an optical branching part. The circulator 20 is formed by, for example, a Faraday rotator, a half-wave plate, a polarizing beam splitter and a reflecting mirror.

The first optical element 30 is, for example, a half-wave plate arranged so as to have an azimuth angle of 22.5 degrees with respect to the plane of polarization of the first linearly polarized light incident from the circulator 20 . The first optical element 30 rotates the plane of polarization of the first linearly polarized light incident from the circulator 20 by 45 degrees and outputs the first linearly polarized light to the optical path section 40 . The first linearly polarized light whose plane of polarization is rotated 45 degrees by the first optical element 30 is divided into a first linearly polarized light CW1 that is P-polarized light and a second linearly polarized light CCW1 that is S-polarized light orthogonal to the first linearly polarized light CW1. have.

Also, the first optical element 30 rotates the polarization plane of the second linearly polarized light, which is the linearly polarized light incident from the optical path section 40 , by 45 degrees, and outputs the second linearly polarized light to the circulator 20 .

The optical path section 40 has a first beam splitter 41 , a second beam splitter 42 , a first optical path 43 , a second optical path 44 and a second optical element 45 .

The first beam splitter 41 emits the first linearly polarized light CW<b>1 to the first optical path 43 and the second linearly polarized light CCW<b>1 to the second optical path 44 . The first beam splitter 41 receives the third linearly polarized light CW2 from the second optical path 44 and the fourth linearly polarized light CCW2 from the first optical path 43 . The third linearly polarized light CW2 and the fourth linearly polarized light CW2 are polarization components of the second linearly polarized light emitted to the first optical element 30 that are orthogonal to each other.

The second beam splitter 42 receives the first linearly polarized light CW<b>1 from the first optical path 43 and the second linearly polarized light CCW<b>1 from the second optical path 44 . The second beam splitter 42 also emits the third linearly polarized light CW2 to the second optical path 44 and the fourth linearly polarized light CCW2 to the first optical path 43 .

The first beam splitter 41 and the second beam splitter 42 split incident light into a P-polarized component and an S-polarized component, and synthesize and emit the P-polarized component and the S-polarized component. The first beam splitter 41 and the second beam splitter 42 are, for example, prism beam splitters, but they may be planar beam splitters or wedge beam splitters.

The first optical path 43 guides the first linearly polarized light CW1 introduced from the first beam splitter 41 to the second beam splitter 42, and directs the fourth linearly polarized light CCW2 introduced from the second beam splitter 42 to the first beam splitter 43. 41. The second optical path 44 guides the second linearly polarized light CCW2 introduced from the first beam splitter 41 to the second beam splitter 42, and directs the third linearly polarized light CW2 introduced from the second beam splitter 42 to the first beam splitter. 41.

The first optical path 43 is a PANDA fiber with one end optically connected to the first beam splitter 41 and the other end optically connected to the second beam splitter 42 . The second optical path 44 is a PANDA fiber with one end optically connected to the first beam splitter 41 and the other end optically connected to the second beam splitter 42 . The first optical path 43 and the second optical path 44 may be polarization-maintaining fibers such as bow-tie fibers and elliptical jacket fibers. A second optical element 45 is arranged in the second optical path 44 .

The second optical element 45 has a first (quarter) wave plate 46 , a second (quarter) wave plate 47 and a 45 degree Faraday rotator 48 .

The first (quarter) wave plate 46 is a quarter wave plate arranged with its optical axis inclined by 45 degrees with respect to the slow axis and fast axis of the PANDA fiber forming the second optical path 44. . The first (quarter) wave plate 46 converts linearly polarized light into circularly polarized light and circularly polarized light into linearly polarized light.

The second (1/4) wavelength plate 47 is a quarter wavelength plate having an optical axis inclined by -45 degrees with respect to the slow axis and the fast axis of the PANDA fiber forming the second optical path 44. be. A second (quarter) wave plate 47 converts the circularly polarized light from the 45 degree Faraday rotator 48 into linearly polarized light and converts the linearly polarized light into circularly polarized light.

The 45-degree Faraday rotator 48 is a Faraday rotator that changes the phase of circularly polarized light incident from each of the first (1/4) wavelength plate 46 and the second (1/4) wavelength plate 47 .

The 45-degree Faraday rotator 48 converts the phase of the second linearly polarized light CCW1 emitted from the second (1/4) wavelength plate 47 into the second linearly polarized light incident on the first (1/4) wavelength plate 46 . The phase of the circularly polarized light incident from the first (quarter) wave plate 46 is changed so as to be 45° shifted from the phase of the linearly polarized light CCW1. The 45-degree Faraday rotator 48 converts the phase of the third linearly polarized light CW2 emitted from the first (1/4) wavelength plate 46 into the third linearly polarized light incident on the second (1/4) wavelength plate 47. The phase of the circularly polarized light is changed so that it is -45 shifted from the phase of CW2.

The pressure sensor 50 is placed at the tip of the PANDA fiber 80, optically connected to the second beam splitter 42 via the PANDA fiber 80, and inserted into a relatively narrow location such as a patient's blood vessel. The pressure sensor 50 receives the linearly polarized light emitted from the light emitting unit 10 as incident light, and when the incident light is incident via the optical fiber 80, the pressure sensor 50 emits return light corresponding to the applied pressure. .

The detection signal generator 60 has a third beam splitter 61, a first light receiving element 62, a second light receiving element 63, and a signal processing circuit 70, and receives the second linearly polarized light split by the circulator 20. do. The detection signal generation unit 60 separates the second linearly polarized light into an S-polarized component and a P-polarized component, receives the S-polarized component and the P-polarized component, converts them into electrical signals, and differentially amplifies them, thereby generating pressure sensor signals. A detection signal Ed corresponding to the pressure applied to 50 is output. The third beam splitter 61 is a polarizing beam splitter (PBS) of prism type, planar type, wedge substrate type, optical waveguide type, or the like. The component 65 is separated.

Each of the first light receiving element 62 and the second light receiving element 63 is, for example, a PIN photodiode. The first light receiving element 62 receives the S polarized light component 64 and the second light receiving element 63 receives the P polarized light component 65 . Each of the first light-receiving element 62 and the second light-receiving element 63 photoelectrically converts the received light and outputs an electrical signal corresponding to the amount of received light. The signal processing circuit 70 differentially amplifies the electrical signal representing the S-polarized component and the electrical signal representing the P-polarized component, thereby outputting a detection signal Ed corresponding to the pressure applied to the pressure sensor 50 .

FIG. 2 is an enlarged cross-sectional view of the portion indicated by broken line A in FIG.

The pressure sensor 50 has a quarter wave plate 51 , a Faraday rotator 52 , a mirror element 53 , a pressure receiving element 54 and a magnetic body 55 . The pressure sensor 50 is arranged at the tip of the PANDA fiber 80 , and emits return light according to the pressure applied to the pressure receiving element 54 when incident light is incident through the optical path section 40 and the PANDA fiber 80 .

The quarter-wave plate 51 is disposed with its optical axis inclined by 45 degrees with respect to the slow axis and fast axis of the PANDA fiber 80 optically connecting the second beam splitter 42 to the second beam splitter 42 . wave plate. The quarter-wave plate 51 converts the polarization state of linearly polarized incident light into circularly polarized light, and converts the polarized state of return light incident as circularly polarized light from the Faraday rotator 52 into linearly polarized light.

The Faraday rotator 52 is a granular film having a dielectric and nano-order magnetic particles dispersed in the dielectric while being stably phase-separated from the dielectric. The Faraday rotator 52 is a magnetic field sensor element arranged on the end surface of the quarter-wave plate 51 and detecting a magnetic field. The magnetic particles may have an oxide formed in a small portion such as the outermost layer, but in the entire Faraday rotator 52, the magnetic particles are Dispersed singly in the thin film. The distribution of the magnetic particles in the Faraday rotator 52 may not be completely uniform, and may be slightly biased. If a highly transparent dielectric is used, the Faraday rotator 52 has optical transparency due to the presence of magnetic particles in the dielectric with a size smaller than the wavelength of light.

The Faraday rotator 52 is not limited to a single layer, and may be a multilayer film in which granular films and dielectric films are alternately laminated. By forming the Faraday rotator 52 by forming a multilayer film of granular films, a larger Faraday rotation angle can be obtained by multiple reflection within the granular film.

The dielectric of the Faraday rotator 52 is preferably a fluoride (metal fluoride) such as magnesium fluoride (MgF ₂ ), aluminum fluoride (AlF ₃ ) or yttrium fluoride (YF ₃ ). Dielectrics include tantalum oxide (Ta ₂ O ₅ ), silicon dioxide (SiO ₂ ), titanium dioxide (TiO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), zirconium dioxide (ZrO ₂ ), hafnium dioxide ( HfO ₂ ), and oxides such as aluminum trioxide (Al ₂ O ₃ ). Fluorides are preferable to oxides for good phase separation between the dielectric and the magnetic particles, and magnesium fluoride, which has a high transmittance, is particularly preferable.

The material of the magnetic particles is not particularly limited as long as it produces the Faraday effect. Examples of the material of the magnetic particles include ferromagnetic metals such as iron (Fe), cobalt (Co) and nickel (Ni). These alloys are mentioned. Examples of alloys of Fe, Co and Ni include FeNi alloys, FeCo alloys, FeNiCo alloys, and NiCo alloys. The Faraday rotation angles per unit length of Fe, Co and Ni are two to three orders of magnitude larger than those of magnetic garnets applied to conventional Faraday rotators.

The mirror element 53 is formed on the Faraday rotator 52 and reflects the light transmitted through the Faraday rotator 52 toward the Faraday rotator 52 . As the mirror element 53, for example, a silver (Ag) film, a gold (Au) film, an aluminum (Al) film, a dielectric multilayer mirror, or the like can be used. In particular, an Ag film with a high reflectance and an Au film with a high corrosion resistance are preferable because they are easy to form. The thickness of the mirror element 53 may be any size that ensures a sufficient reflectance of 98% or more. By reciprocating light in the Faraday rotator 52 using the mirror element 53, the Faraday rotation angle can be increased.

3(a) is a perspective view (part 1) of the pressure receiving element 54, FIG. 3(b) is a perspective view (part 2) of the pressure receiving element 54, and FIG. 3(c) is a perspective view of FIG. 3 is a perspective cross-sectional view of the pressure receiving element 54 taken along line BB. FIG.

The pressure receiving element 54 has a base 56, a support portion 57, and an elastic portion 58, and is formed by cutting silicon, which can be finely processed with high accuracy, by laser processing, etching processing, or the like.

The base 56 has a cylindrical shape with an outer diameter that is the same as the outer diameter of the PAND fiber 80 . An opening 59 in which the magnetic body 55 is arranged is formed on one side surface of the base 56, and an elastic portion 58 is arranged on the other side surface.

The support portion 57 has a columnar shape, one end of which is connected to the central portion of the elastic portion 58 , and is arranged inside the base 56 . A magnetic body 55 is arranged at the tip of the support portion 57 . The magnetic body 55 is arranged at the tip of the cylindrical support portion, so that it is arranged close to the Faraday rotator 52, which is the magnetic field sensor element.

The elastic part 58 has a spiral or helical shape, is arranged on the other side surface of the base 56, and has a water-repellent film formed of a hydrophobic material such as a fluorine-based substance arranged on its outer surface. Between the elastic portions 58, a single groove 58a is formed that curves and extends spirally. The grooves formed between the elastic portions 58 are formed to extend along the Archimedean spiral with the origin at the center of the bottom surface of the support portion 57 . The grooves formed between the elastic portions 58 are formed so as to extend along the Archimedean spiral, so that the elastic portions 58 have a uniform width.

The elastic portion 58 bends toward the inside of the base 56 when pressed from the outside. When the elastic portion 58 bends toward the inside of the base 56 , the support portion 57 arranged in the central portion of the elastic portion 58 moves toward the opening portion 59 . When the support portion 57 moves toward the opening 59 , the magnetic body 55 arranged at the tip of the support portion 57 moves toward the Faraday rotator 52 .

The magnetic body 55 is a thin-film permanent magnet having a circular planar shape having the same shape as the diameter of the support portion 57 . The magnetic body 55 is, for example, an iron-platinum (Fe--Pt) magnet. The magnetic body 55 may be a permanent magnet other than an iron-platinum magnet such as a neodymium-iron-boron (Nd--Fe--B) magnet and a samarium-cobalt (Sm--Co) magnet. However, when the pressure sensor 50 is inserted into the human body, the magnetic body 55 is preferably an iron-platinum magnet that has little effect on the human body.

4A shows the pressure sensor 50 with no pressure applied, and FIG. 4B shows the pressure sensor 50 with pressure applied. FIG. 5 is a diagram showing the relationship between the distance between the Faraday rotator 52 and the magnetic body 55 and the magnetic field applied to the Faraday rotator 52. As shown in FIG.

In the pressure sensor 50 , when pressure is applied from the outside of the elastic portion 58 , the elastic portion 58 bends toward the inside of the base 56 . The magnetic body 55 moves toward the Faraday rotator 52 in accordance with the bending of the elastic portion 58 toward the inside of the base 56 .

As the magnetic body 55 moves toward the Faraday rotator 52, the magnetic field H applied to the Faraday rotator 52 increases. The magnetic field H applied to the Faraday rotator 52 increases linearly as the distance D between the Faraday rotator 52 and the magnetic body 55 decreases.

The circularly polarized light incident on the Faraday rotator 52 from the quarter-wave plate 51 is transmitted through the Faraday rotator 52, reflected by the mirror element 53, transmitted through the Faraday rotator 52 again, and becomes return light. The return light that has passed through the Faraday rotator 52 is again incident on the quarter-wave plate 51 .

The circularly polarized light incident on the Faraday rotator 52 from the quarter-wave plate 51 changes its phase according to the magnetic field applied to the Faraday rotator 52 . Moreover, the circularly polarized light reflected by the mirror element 53 further changes its phase according to the magnetic field applied to the Faraday rotator 52 .

(Action and effect of the pressure sensor device according to the embodiment)
The pressure sensor device 1 detects a magnetic field applied to the Faraday rotator 52 that changes according to the distance between the Faraday rotator 52 and the magnetic body 55 without using a Fabry-Perot resonator. The pressure applied to sensor 50 is detected. Since the magnetic field applied to the Faraday rotator 52 changes according to the distance between the Faraday rotator 52 and the magnetic body 55, the distance between the Faraday rotator 52 and the magnetic body 55 is made uniform. They do not have to be manufactured together. Since the pressure sensor device 1 does not have to be manufactured with the distance between the Faraday rotator 52 and the magnetic body 55 uniform, it is easier to manufacture than the pressure sensor device using a Fabry-Perot resonator. and the manufacturing cost can be reduced.

Further, since the magnetic field applied to the Faraday rotator 52 changes according to the distance between the Faraday rotator 52 and the magnetic body 55, changes linearly with Since the pressure sensor device 1 detects pressure using a magnetic field that linearly changes according to a change in the distance between the Faraday rotator 52 and the magnetic body 55, it uses the resonance wavelength of the Fabry-Perot resonator. The pressure can be detected with higher precision than the pressure sensor device that detects the pressure by using a pressure sensor.

In addition, in the pressure sensor device 1, the pressure receiving element 54 is made of silicon that can be microfabricated with high accuracy, so that it can be easily miniaturized.

In addition, in the pressure sensor device 1, since a water-repellent film is formed on the outer surface of the spiral elastic portion 58, liquid such as blood is less likely to enter the inside of the base 56 through the gaps of the elastic portion 58. There is little possibility that the measurement accuracy will deteriorate due to the intrusion of the liquid into the base 56 .

(Modification of the pressure sensor device according to the embodiment)
In the pressure sensor device 1, the pressure receiving element 54 is formed by cutting silicon. It may be formed by processing to

Further, in the pressure sensor device 1, the magnetic body 55 is arranged at the tip of the columnar support portion 57 arranged in the central portion of the elastic portion 58, but in the pressure sensor device according to the embodiment, the magnetic body is It may have a cylindrical shape and be arranged in the center of the elastic portion 58 .

In the pressure sensor device 1, the elastic portion 58 has a water-repellent film formed on its outer surface. A water-repellent film may be formed on both the inner surface and the inner surface. Also, the elastic portion may not have a water-repellent film formed on either the outer surface or the inner surface.

Further, in the pressure sensor device 1, the elastic portion 58 of the pressure receiving element 54 has a uniform width, but in the pressure sensor device according to the embodiment, the width of the elastic portion may not be uniform. In the pressure-receiving element 54, the elastic portion 58 has a uniform width. Therefore, when pressure is applied, stress is concentrated on the outer side of the elastic portion 58 near the base 56, and the displacement amount of the outer side of the elastic portion 58 is reduced. It becomes larger than the amount of displacement inside the elastic portion 58 . In the pressure-receiving element 54, the amount of displacement of the outer side of the elastic portion 58 is large. There is a risk of intrusion from

FIG. 6A is a perspective view (Part 1) of the pressure receiving element according to the first modification, and FIG. 6B is a perspective view (Part 2) of the pressure receiving element according to the first modification. (c) is a front view of a pressure receiving element according to a first modified example.

The pressure receiving element 154 differs from the pressure receiving element 54 in that it has a base 156 and an elastic portion 158 instead of the base 56 and the elastic portion 58 . The configuration and function of the constituent elements of the pressure receiving element 154 other than the base 156 and the elastic portion 158 are the same as the configuration and function of the constituent elements of the pressure receiving element 54 denoted by the same reference numerals, so detailed description thereof will be omitted here. The base 156 differs from the base 56 in that its length is longer than that of the base 56 . Since the base 156 is longer than the base 56, it can be arranged so as to cover the quarter-wave plate 51, the Faraday rotator 52 and the mirror element 53, and a larger magnetic body 55 can be installed. be able to.

The elastic portion 158 is formed so that the width becomes narrower from one end connected to the base 156 toward the other end connected to the support portion 57 . Specifically, the elastic portions 158 are formed such that grooves 158a formed between the elastic portions 158 extend along a logarithmic spiral with the center of the bottom surface of the support portion 57 as the origin. The groove 158a may be formed to extend along an algebraic spiral other than a logarithmic spiral such as a hyperbolic spiral and a litius spiral.

The pressure-receiving element 154 is formed such that the width of the elastic portion 158 becomes narrower from one end connected to the base 156 toward the other end connected to the support portion 57 , so that the pressure-receiving element 154 is formed so that the width of the elastic portion 158 decreases toward the other end connected to the support 57 . The amount of displacement of the outer side of the elastic portion 58 does not increase due to concentration of stress. Since the displacement of the pressure receiving element 154 outside the elastic portion 58 is not large, there is little possibility that liquid will enter the groove 58a outside the elastic portion 58 from the outside groove 58a.

Further, in the pressure sensor device 1, the elastic portion 58 of the pressure receiving element 54 is formed with a single groove, but in the pressure sensor device according to the embodiment, the elastic portion may be formed with a plurality of grooves. In the pressure-receiving element 54, the elastic portion 58 is formed with a single groove. The portion 57 may tilt. In the pressure sensor device 1, the inclination of the supporting portion 57 that supports the magnetic body 55 may reduce the detection accuracy when detecting the change in the magnetic field according to the pressure.

FIG. 7A is a perspective view (Part 1) of the pressure receiving element according to the second modification, and FIG. 7B is a perspective view (Part 2) of the pressure receiving element according to the second modification. (c) is a front view of a pressure receiving element according to a second modification.

The pressure receiving element 254 differs from the pressure receiving element 154 in having an elastic portion 258 instead of the elastic portion 158 . The configuration and function of the constituent elements of the pressure receiving element 254 other than the elastic portion 258 are the same as the configuration and function of the constituent elements of the pressure receiving element 154 denoted by the same reference numerals, so detailed description thereof will be omitted here.

The elastic portion 258 differs from the elastic portion 158 in that two grooves, a first groove 258a and a second groove 258b, are formed. The first groove 258a and the second groove 258b are formed to extend along a logarithmic spiral with the center of the bottom surface of the support portion 57 as the origin. The ends of the first groove 258a and the second groove 258b on the side of the base 156 are arranged around the support portion 57 with an interval of 180 degrees. Also, the ends of the first groove 258a and the second groove 258b on the side of the support portion 57 are arranged around the support portion 57 with an interval of 180 degrees.

Since the first groove 258a and the second groove 258b are formed in the elastic portion 258 of the pressure receiving element 254, the inclination of the support portion 57 that supports the magnetic body 55 makes it difficult to detect changes in the magnetic field according to the pressure. There is little possibility that the detection accuracy will decrease. The pressure receiving element 254 has two grooves, that is, the ends of the first groove 258a and the second groove 258b are arranged 180 degrees apart, and is symmetrical with respect to the center of the bottom surface of the support portion 57. , the possibility that the support portion 57 is tilted is further reduced.

8A is a perspective view (part 1) of the pressure receiving element according to the third modification, and FIG. 8B is a perspective view (part 2) of the pressure receiving element according to the third modification. (c) is a front view of a pressure receiving element according to a third modified example.

The pressure receiving element 354 differs from the pressure receiving element 154 in having an elastic portion 358 instead of the elastic portion 158 . The configuration and function of the constituent elements of the pressure receiving element 354 other than the elastic portion 358 are the same as the configuration and function of the constituent elements of the pressure receiving element 154 to which the same reference numerals are assigned, so detailed description thereof will be omitted here.

The elastic portion 358 differs from the elastic portion 158 in that three grooves, ie, a first groove 358a, a second groove 358b and a third groove 358c are formed. The first groove 358a, the second groove 358b, and the third groove 358c are formed to extend along a logarithmic spiral with the center of the bottom surface of the support portion 57 as the origin. The first groove 358a, the second groove 358b, and the third groove 358c are formed, for example, so as to extend along a logarithmic spiral whose origin is the center of the bottom surface of the support portion 57 represented by the following formula.
Xt＝(0.092*exp(-0.06*t))*cos(t)
Yt=(0.092*exp (-0.06*t))*sin(t)
Here, t is a numerical value greater than or equal to 0*π and less than or equal to 5*π.

The ends of the first groove 358a, the second groove 358b, and the third groove 358c on the side of the base 156 are arranged around the support portion 57 at intervals of 120 degrees. Also, the ends of the first groove 358a, the second groove 358b and the third groove 358c on the side of the support portion 57 are arranged at intervals of 120 degrees around the support portion 57. As shown in FIG.

FIG. 9(a) is a diagram showing the pressure sensor with no pressure applied, and FIG. 9(b) is a diagram showing the pressure sensor with pressure applied. A pressure sensor 50 a shown in FIGS. 9( a ) and 9 ( b ) differs from the pressure sensor 50 in that a pressure receiving element 354 is arranged instead of the pressure receiving element 54 . Further, the pressure sensor 50a is different from the pressure sensor 50 in that a magnetic body 55a is arranged instead of the magnetic body 55. As shown in FIG. The magnetic body 55a has the same configuration and function as the magnetic body 55 except that the magnetic body 55a is larger than the magnetic body 55, so detailed description thereof will be omitted here.

In the pressure receiving element 354, since the first groove 358a, the second groove 358b and the third groove 358c are formed in the elastic portion 358, the inclination of the support portion 57 supporting the magnetic body 55 causes the change of the magnetic field according to the pressure. There is little risk of deterioration in detection accuracy when detecting . The pressure-receiving element 254 has three grooves, that is, a first groove 358a, a second groove 358b, and a third groove 358c. , so that the support portion 57 is less likely to incline.

FIG. 10 is a diagram showing the results of stress simulation of the pressure receiving element 354. FIG. FIG. 10(a) shows the amount of displacement of the elastic portion 358 according to the application of pressure, and FIG. 10(b) shows the von Mises stress generated in the elastic portion 358 according to the application of pressure. 10A is a cross-sectional view of the pressure receiving element 354 and the magnetic body 55a, and FIG. 10B is a plan view of the pressure receiving element 354. FIG.

As shown in FIG. 10A, in the pressure receiving element 354, the elastic portion 358 causes the magnetic body 55a to move parallel to the pressure application direction without tilting the support portion 57 when pressure is applied. Moving.

Further, as shown in FIG. 10A, in the pressure receiving element 354, the von Mises stress is applied to the elastic portion 358 substantially uniformly from the central portion near the support portion 57 to the outer edge portion near the base 156. , the phenomenon of stress concentration on the outside of the elastic portion 358 does not occur.

Also, in the pressure sensor device 1, a single pressure receiving element 54 is arranged, but in the pressure sensor device according to the embodiment, a plurality of pressure receiving elements may be arranged.

11 is a partially enlarged cross-sectional view of a pressure sensor device according to a fourth modification, FIG. 12 is a partially enlarged exploded cross-sectional view of the pressure sensor device shown in FIG. 11, and FIG. 13(b) is a plan view of the second pressure receiving element shown in FIG. 11. FIG.

The pressure sensor 50b differs from the pressure sensor 50a in that it has a first pressure receiving element 454 and a second pressure receiving element 554 instead of the pressure receiving element 354 . Further, the pressure sensor 50b differs from the pressure sensor 50a in having a yoke 55b. The configuration and function of the components of the pressure sensor 50b other than the first pressure receiving element 454, the second pressure receiving element 554, and the yoke 55b are the same as the configuration and function of the components of the pressure sensor 50a denoted by the same reference numerals. Detailed description is omitted.

The first pressure receiving element 454 differs from the pressure receiving element 354 in that it has a base 456 and an elastic portion 158 instead of the base 156 and the elastic portion 358 . The configuration and function of the first pressure receiving element 454 other than the base 456 and the elastic portion 158 are the same as the configuration and function of the pressure receiving element 354, so detailed description thereof will be omitted here. Also, since the configuration and function of the elastic portion 158 have been described with reference to FIG. 6 and the like, detailed description thereof will be omitted here.

The second pressure receiving element 554 differs from the pressure receiving element 354 in that it has a base 556 and an elastic portion 558 instead of the base 156 and the elastic portion 358 . Further, the second pressure receiving element 554 differs from the pressure receiving element 354 in that it does not have the support portion 57 . The configuration and function of the second pressure receiving element 554 other than the base 556 and the elastic portion 558 are the same as the configuration and function of the pressure receiving element 354, so detailed description thereof will be omitted here. The elastic portion 558 differs from the elastic portion 158 in that a yoke receiving hole 557 is formed in the center.

The yoke 557 is made of a magnetic material such as permalloy and has a substantially truncated cone shape. The lower base of the yoke 557 is connected to the end surface of the magnetic body 55a, and the upper base of the yoke 55b is engaged with the yoke receiving hole 557 of the elastic portion 558. As shown in FIG.

FIG. 14(a) shows the pressure sensor 50b with no pressure applied, and FIG. 14(b) shows the pressure sensor 50b with pressure applied.

In the pressure sensor 50b, one end face of the magnetic body 55a is supported by the support portion 57, and the other end face of the magnetic body 55a is engaged with the second pressure receiving element 554 via the yoke 55b. Since it moves, it is unlikely that the accuracy of detecting changes in the magnetic field will be degraded.

Moreover, since the pressure sensor 50b has the yoke 55b arranged between the Faraday rotator 52 and the magnetic body 55a, the magnetic field can be efficiently guided from the magnetic body 55a to the Faraday rotator 52. FIG. Although the pressure sensor 50b has the yoke 55b, the pressure sensor according to the embodiment may not have the yoke. Also, in the pressure sensors 50 and 50a, no yoke is arranged, but in the pressure sensors 50 and 50a, a yoke may be additionally arranged.

In addition, the pressure sensor 50b has the first pressure receiving element 454 and the second pressure receiving element 554 each having an elastic portion in which a groove extending spirally curved is formed. The shape of the elastic portion of the element and the second pressure receiving element is not limited.

FIG. 15 is a plan view of a second pressure receiving element according to a modification.

The second pressure receiving element 654 differs from the second pressure receiving element 554 in having an elastic portion 658 instead of the elastic portion 558 . The configuration and function of the second pressure receiving element 654 other than the elastic portion 658 are the same as the configuration and function of the pressure receiving element 354, so detailed description thereof will be omitted here.

The elastic portion 658 has a first elastic member 658a, a second elastic member 658b, a third elastic member 658c, and a yoke support member 658d. The first elastic member 658a, the second elastic member 658b, and the third elastic member 658c are elastic members such as springs, and are arranged at intervals of 120 degrees. One ends of the first elastic member 658a, the second elastic member 658b, and the third elastic member 658c are connected to the yoke support portion 658d, and the other ends of the first elastic member 658a, the second elastic member 658b, and the third elastic member 658c are connected to the base. It is connected to platform 554 . The yoke support member 658d has a ring-shaped planar shape, and is formed with a yoke receiving hole 658e with which the upper base of the yoke 557 is engaged.

1 Pressure Sensor Device 10 Light Emitting Part 20 Circulator (Optical Branching Part)
30 first optical element 40 optical path section 50, 50a, 50b pressure sensor 51 quarter wave plate 52 Faraday rotator (magnetic field sensor element)
53 mirror element 54, 154, 254, 354 pressure receiving element 55, 55a magnetic body 56, 156 base 57 support portion 58, 158, 258, 358 elastic portion 59 opening 60 detection signal generating portion

Claims (10)

a light emitting unit that emits incident light;
an optical fiber optically connected to the light emitting unit;
a pressure sensor disposed at the tip of the optical fiber and configured to emit return light corresponding to the applied pressure when the incident light is incident through the optical fiber;
a detection signal generator optically connected to the pressure sensor via the optical fiber and outputting a detection signal corresponding to the pressure applied to the pressure sensor based on the returned light; pressure sensor
a magnetic body;
a magnetic field sensor element that is arranged in proximity to the magnetic body and that emits return light according to the magnetic field when the incident light is incident;
a pressure-receiving element that holds the magnetic body such that the distance between the magnetic field sensor element and the magnetic body changes according to the application of pressure;
A pressure sensor device comprising: The pressure receiving element is
a base having a cylindrical shape and having an opening formed on one side;
a support portion disposed inside the base and holding the magnetic body;
an elastic part disposed on the other side of the base, having one end connected to the base and the other end connected to the support, and having one or more spiral grooves formed thereon;
2. The pressure sensor device of claim 1, comprising: 3. The pressure sensor device according to claim 2, wherein said pressure receiving element is made of silicon. 4. The pressure sensor device according to claim 3, wherein the elastic portion has a water-repellent film formed on at least one of a first surface facing the magnetic field sensor element and a second surface opposite to the first surface. The pressure sensor according to any one of claims 2 to 4, wherein the width of the elastic portion becomes narrower from the one end connected to the base toward the other end connected to the support portion. Device. 6. The pressure sensor device according to claim 5, wherein said groove is formed so as to extend along a logarithmic spiral whose origin is the center of the bottom surface of said support. the elastic portion has a first groove and a second groove;
The ends of the first groove and the second groove on the base side are arranged 180 degrees apart,
The pressure sensor device according to any one of claims 2 to 6, wherein the end portions of the first groove and the second groove on the side of the support portion are separated by 180 degrees. The elastic portion has a first groove, a second groove and a third groove,
The ends of the first groove, the second groove, and the third groove on the base side are arranged at intervals of 120 degrees,
The pressure sensor device according to any one of claims 2 to 6, wherein ends of the first groove, the second groove, and the third groove on the side of the support portion are spaced apart by 120 degrees. . The pressure sensor device according to any one of claims 1 to 8, wherein said pressure sensor further comprises a second pressure receiving element holding an end opposite to the end of said magnetic material held by said pressure receiving element. . a base having a cylindrical shape and having an opening formed on one side;
a support portion disposed inside the base and holding the magnetic body;
an elastic part disposed on the other side of the base, having one end connected to the base and the other end connected to the support, and having one or more spiral grooves formed thereon;
A pressure receiving element characterized by comprising:

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