Optical pressure sensor and method for manufacturing the same

Abstract

To sufficiently improve the measurement accuracy of an optical pressure sensor.SOLUTION: An optical pressure sensor comprises: a first member; a second member; and an optical transmission medium. The first member and the second member each have a plate-shaped portion. The first member has a lateral wall portion that extends from the plate-shaped portion of the first member and that is joined at a distal end surface to a surface of the plate-shaped portion of the second member. An airtight space is defined by two plate-shaped portions and the lateral wall portion. The optical transmission medium is attached to a surface of one of the two plate-shaped portions on a side opposite an airtight space-side surface. A first reflective film that reflects light transmitted by the optical transmission medium is formed on the surface of the plate-shaped portion of the first member facing the airtight space. The surface of the plate-shaped portion of the second member on the first member side includes a first region facing the airtight space, and a second region facing the distal end surface of the lateral wall portion of the first member. A second reflective film that reflects light transmitted by the optical transmission medium is formed across the entirety of the first region.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The technology disclosed in this specification relates to an optical pressure sensor and a method for manufacturing the same.

Background Art

[0002] For example, in order to measure the pressure of a coronary artery for the purpose of specifying the fractional flow reserve (FFR), a Fabry - Perot interferometric optical pressure sensor is used (see, for example, Patent Documents 1 and 2).

[0003] The Fabry - Perot interferometric optical pressure sensor includes an optical element which is a box body in which a sealed space called a cavity is formed inside, and an optical transmission medium attached to the optical element. The tip of the optical element constitutes a thin plate - shaped diaphragm portion that deforms (bends) according to an external pressure (for example, the pressure inside the coronary artery). Note that the optical element is composed of a member having a diaphragm portion and another member joined to the member.

[0004] In addition, two reflective films facing each other (directly facing) across the sealed space are formed inside the optical element. Specifically, one reflective film is formed on the surface of the diaphragm portion facing the sealed space, and the other reflective film is formed at a position facing the reflective film across the sealed space. The distance between the two reflective films (hereinafter referred to as the "cavity length") changes as the diaphragm portion deforms. That is, the cavity length changes according to the external pressure.

[0005] The light incident into the sealed space of the optical element through the optical transmission medium is multiply reflected between the two reflective films facing each other, and interference of light occurs during this multiple reflection. The interference peak wavelength in the multiple reflection changes according to the cavity length. That is, the interference peak wavelength in the multiple reflection changes according to the external pressure. The Fabry - Perot interferometric optical pressure sensor utilizes such characteristics to measure the external pressure based on the interference peak wavelength of the multiple reflection of light in the sealed space inside the optical element.

[0006] In a conventional Fabry - Perot interferometric optical pressure sensor, each reflective film is formed only in the central portion of the surface of the member on which each reflective film is formed and facing the sealed space, and is not formed in the peripheral portion. This is because, in order to avoid the occurrence of poor bonding due to the formation of the reflective film on the bonding surface when joining two members, the reflective film is formed only in a region with a margin of a predetermined size (for example, 20 μm to 30 μm) from the bonding surface.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] As described above, in a conventional Fabry - Perot interferometric optical pressure sensor, since each reflective film is formed only in the central portion of the surface of the member on which each reflective film is formed and facing the sealed space, the light reflection intensity by the reflective film in the cavity cannot be sufficiently improved. Also, in a conventional Fabry - Perot interferometric optical pressure sensor, a displacement in the formation position of the reflective film occurs on the surface of the member facing the sealed space where each reflective film is formed, and there is a possibility that the background of the interference waveform increases or decreases due to this displacement. As a result, there is a problem that the measurement accuracy of the optical pressure sensor cannot be sufficiently improved in a conventional Fabry - Perot interferometric optical pressure sensor.

[0009] This specification discloses a technology capable of solving the above - described problems.

Means for Solving the Problems

[0010] The technology disclosed in this specification can be realized, for example, in the following forms.

[0011] (1) The optical pressure sensor disclosed in this specification includes a first member, a second member, and an optical transmission medium. Each of the first member and the second member has a plate-like portion. The first member and the second member are joined to each other in a posture where the two plate-like portions face each other. The first member has a side wall portion extending from the plate-like portion of the first member and having a tip surface joined to the surface of the plate-like portion of the second member. A sealed space is defined by the two plate-like portions and the side wall portion. The optical transmission medium is attached to the surface of one of the two plate-like portions on the side opposite to the surface on the sealed space side. A first reflective film that reflects the light transmitted by the optical transmission medium is formed on the surface of the plate-like portion of the first member facing the sealed space. The surface of the plate-like portion of the second member on the first member side includes a first region facing the sealed space and a second region facing the tip surface of the side wall portion of the first member. A second reflective film that reflects the light transmitted by the optical transmission medium is formed over the entire first region.

[0012] Thus, in this optical pressure sensor, the second reflective film is formed over the entire first region of the surface of the plate-like portion of the second member on the first member side that faces the sealed space. Therefore, according to this optical pressure sensor, the reflection intensity of light by the second reflective film can be sufficiently improved, and the occurrence of displacement in the formation position of the second reflective film in the first region of the surface of the plate-like portion of the second member on the first member side can be avoided. Therefore, according to this optical pressure sensor, the measurement accuracy of the optical pressure sensor can be sufficiently improved.

[0013] (2) In the above optical pressure sensor, among the first reflection film and the second reflection film, the thickness of the reflection film farther from the optical transmission medium may be configured to be thicker than the thickness of the reflection film closer to the optical transmission medium. According to this optical pressure sensor, it is possible to suppress light that undergoes multiple reflections in the sealed space from passing through the reflection film farther from the optical transmission medium, and it is possible to suppress a decrease in the measurement accuracy of the optical pressure sensor due to such transmission. Further, according to this optical pressure sensor, since the thickness of the reflection film closer to the optical transmission medium can be made relatively thin, the amount of light passing through the reflection film and reaching the sealed space can be increased. As a result, the peak value of the interference wavelength of multiple reflections can be increased, and the measurement accuracy of the optical pressure sensor can be improved.

[0014] (3) In the above optical pressure sensor, among the first reflection film and the second reflection film, the thickness of the reflection film closer to the optical transmission medium may be configured to be thicker than the thickness of the reflection film farther from the optical transmission medium. According to this optical pressure sensor, the reflection film formed on the diaphragm portion, which is a very thin plate-like portion, can be made relatively thin, and the thermal stress caused by the difference in thermal expansion between the diaphragm portion and the reflection film can be reduced. As a result, it is possible to suppress a decrease (temperature drift) in the measurement accuracy of the optical pressure sensor due to such thermal stress.

[0015] (4) In the above optical pressure sensor, the first member and the second member may be formed of the same material. According to this optical pressure sensor, the difference in the coefficient of thermal expansion between the first member and the second member can be reduced, and it is possible to suppress a decrease in the measurement accuracy of the optical pressure sensor due to the difference in the coefficient of thermal expansion.

[0016] (5) In the above optical pressure sensor, the portion of the plate-shaped portion of the second member facing the sealed space may be configured to form a diaphragm portion that deforms under external pressure. According to this optical pressure sensor, a reflective film can be formed on the entire surface of the diaphragm portion facing the sealed space. Therefore, according to this optical pressure sensor, problems such as damage to the diaphragm portion, deterioration of the durability of the diaphragm portion, and deterioration of the measurement accuracy of the optical pressure sensor that occur when the reflective film is formed only on a part of the central portion of the surface of the diaphragm portion facing the sealed space can be suppressed.

[0017] (6) In the above optical pressure sensor, the second reflective film may be configured to be continuously formed from the first region to the second region on the surface of the plate-shaped portion of the second member on the first member side. According to this optical pressure sensor, problems such as damage to the diaphragm portion, deterioration of the durability of the diaphragm portion, and deterioration of the measurement accuracy of the optical pressure sensor that occur when the reflective film is formed only on a part of the central portion of the surface of the diaphragm portion facing the sealed space can be effectively suppressed.

[0018] (7) The manufacturing method of the optical pressure sensor disclosed in this specification is a manufacturing method of an optical pressure sensor including a first member and a second member. Each of the first member and the second member has a plate-shaped portion. The first member and the second member are joined to each other in a posture where the two plate-shaped portions face each other. The first member has a side wall portion extending from the plate-shaped portion of the first member and having a tip surface joined to the surface of the plate-shaped portion of the second member. A sealed space is defined by the two plate-shaped portions and the side wall portion. This manufacturing method of the optical pressure sensor includes a first step, a second step, a third step, and a fourth step. The first step is a step of preparing the first member and the second member. The second step is a step of forming a first reflective film that is formed of a specific metal and reflects light on a surface of the plate-shaped portion of the first member facing the plate-shaped portion of the second member and a first member side facing region of the tip surface of the side wall portion of the first member facing the plate-shaped portion of the second member under a vacuum of -10°C or higher, 200°C or lower, and less than standard atmospheric pressure. The third step is a step of forming a second reflective film that is formed of the specific metal and reflects light on a surface of the plate-shaped portion of the second member on the first member side, a second member side facing region facing the tip surface of the side wall portion of the first member, and the entire region surrounded by the second member side facing region under a vacuum of -10°C or higher, 200°C or lower, and less than standard atmospheric pressure. The fourth step is a step of joining the first member and the second member by bringing the first member side facing region of the first member on which the first reflective film is formed into contact with the second member side facing region of the second member on which the second reflective film is formed.

[0019] Thus, in the manufacturing method of this optical pressure sensor, since the first member and the second member can be joined at a temperature that is not excessively high, i.e., -10°C or higher and 200°C or lower, it is possible to suppress the generation of thermal strain in each member during the manufacture of the optical pressure sensor. Also, since no melt or adhesive is used when joining the first member and the second member, it is possible to suppress a deterioration in the quality of the optical pressure sensor caused by the outflow of the melt or adhesive. Furthermore, since the first reflective film and the second reflective film can function as a joining material for joining the first member and the second member, it is possible to realize an improvement in manufacturing efficiency as compared with a manufacturing method in which the formation of the reflective film and the formation of the joining material are carried out as separate processes. Also, since there is no need to use an acid-based chemical when forming the first reflective film and the second reflective film, it is possible to suppress joining defects and a decrease in light transmittance caused by roughening of the surfaces of the first member and the second member due to the acid-based chemical.

[0020] (8) In the manufacturing method of the optical pressure sensor described above, further, before the second step, a fifth step of polishing the first member side facing region, and before the third step, a sixth step of polishing the second member side facing region may be provided. According to the manufacturing method of this optical pressure sensor, it is possible to improve the joining strength between the first member and the first reflective film, and the joining strength between the second member and the second reflective film. As a result, it is possible to improve the joining strength between the first member and the second member.

[0021] (9) In the manufacturing method of the optical pressure sensor described above, the fifth step may be a step of polishing the first member side facing region so that the surface roughness Sa is less than 50 nm, and the sixth step may be a step of polishing the second member side facing region so that the surface roughness Sa is less than 50 nm. According to the manufacturing method of this optical pressure sensor, it is possible to effectively improve the joining strength between the first member and the first reflective film, and the joining strength between the second member and the second reflective film. As a result, it is possible to effectively improve the joining strength between the first member and the second member.

[0022] (10) In the method for manufacturing the optical pressure sensor, further, after the fourth step, a seventh step of attaching an optical transmission medium to a surface of one of the plate-like portions of the first member and the plate-like portion of the second member, which is opposite to the surface on the sealed space side, is provided. The second step and the third step may be configured to be executed such that, among the first reflective film and the second reflective film, the thickness of the reflective film farther from the optical transmission medium in the state after the seventh step is greater than the thickness of the reflective film closer to the optical transmission medium. According to the method for manufacturing the optical pressure sensor, in the manufactured optical pressure sensor, it is possible to suppress light that undergoes multiple reflections in the sealed space from passing through the reflective film farther from the optical transmission medium, and it is possible to suppress a decrease in the measurement accuracy of the optical pressure sensor due to such transmission. Further, according to the method for manufacturing the optical pressure sensor, in the manufactured optical pressure sensor, since the thickness of the reflective film closer to the optical transmission medium can be made relatively thin, the amount of light passing through the reflective film and reaching the sealed space can be increased. As a result, the peak value of the interference wavelength of multiple reflections can be increased, and the measurement accuracy of the optical pressure sensor can be improved.

[0023] (11) In the method for manufacturing the optical pressure sensor, further, after the fourth step, a seventh step of attaching an optical transmission medium to a surface of one of the plate-like portions of the first member and the plate-like portion of the second member, which is opposite to the surface on the sealed space side, is provided. The second step and the third step may be configured to be executed such that, among the first reflective film and the second reflective film, the thickness of the reflective film closer to the optical transmission medium in the state after the seventh step is greater than the thickness of the reflective film farther from the optical transmission medium. According to the method for manufacturing the optical pressure sensor, in the manufactured optical pressure sensor, the reflective film formed on the diaphragm portion, which is a very thin plate-like portion, can be made relatively thin, and the thermal stress caused by the difference in thermal expansion between the diaphragm portion and the reflective film can be reduced. As a result, it is possible to suppress a decrease (temperature drift) in the measurement accuracy of the optical pressure sensor due to such thermal stress.

[0024] (12) In the method for manufacturing the optical pressure sensor, the specific metal may be configured to include at least one of Si, SiC, Al, Cu, Cr, Ni, and Ti. According to the method for manufacturing the optical pressure sensor, the first member and the second member can be more reliably joined at a temperature that is not excessively high, such as -10°C or higher and 200°C or lower.

[0025] (13) In the method for manufacturing the optical pressure sensor, the first member and the second member may be configured to be formed of the same material. According to the method for manufacturing the optical pressure sensor, in the manufactured optical pressure sensor, the difference in the coefficient of thermal expansion between the first member and the second member can be reduced, and it is possible to suppress a decrease in the measurement accuracy of the optical pressure sensor due to the difference in the coefficient of thermal expansion.

[0026] Note that the technology disclosed in this specification can be realized in various forms. For example, it can be realized in the form of an optical pressure sensor, a medical device including the optical pressure sensor, a method for manufacturing them, and the like.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Modes for Carrying Out the Invention

[0028] A. Embodiment: A-1. Configuration of the guide wire 10 with a pressure sensor: FIG. 1 is an explanatory drawing schematically showing the configuration of the guide wire 10 with a pressure sensor in the present embodiment. FIG. 1 shows the configuration of the longitudinal section (YZ section) of the guide wire 10 with a pressure sensor. In FIG. 1, the positive Z-axis direction side is the tip side (distal side) inserted into the body, and the negative Z-axis direction side is the base end side (proximal side) operated by a technician such as a doctor. In FIG. 1, illustration of a part of the guide wire 10 with a pressure sensor is omitted. Also, in FIG. 1, the central axis AX of the guide wire 10 with a pressure sensor is shown as a straight line parallel to the Z-axis direction, but the guide wire 10 with a pressure sensor has flexibility to the extent that it can be curved. These points are the same in the following figures. In this specification, for the guide wire 10 with a pressure sensor and its constituent members, the end on the tip side is referred to as the "tip", the tip and its vicinity are referred to as the "tip portion", the end on the base end side is referred to as the "base end", and the base end and its vicinity are referred to as the "base end portion".

[0029] The guide wire 10 with a pressure sensor is a medical device that is inserted into a patient's body to measure pressure. For example, the guide wire 10 with a pressure sensor is used to measure the pressure in the coronary artery for the purpose of specifying the fractional flow reserve (FFR). Note that the guide wire 10 with a pressure sensor can also be used to measure the pressure at other locations in the body (for example, the pressure in the blood vessels of the brain or the pressure in organs such as the bile duct). The total length of the guide wire 10 with a pressure sensor is, for example, about 1500 mm to 2000 mm, and the outer diameter of the guide wire 10 with a pressure sensor is, for example, about 0.2 mm to 1 mm.

[0030] The guide wire 10 with a pressure sensor includes an optical pressure sensor 12, a proximal core shaft 13, a distal core shaft 15, a coil body 16, and a distal joint portion 17.

[0031] The proximal core shaft 13 is an elongated member that extends along the central axis AX. The outer diameter of the proximal core shaft 13 is substantially constant from the proximal end to the distal end. A through hole 18 that penetrates from the distal end to the proximal end is formed in the proximal core shaft 13, and an optical transmission medium 200 of the optical pressure sensor 12 described later is accommodated in the through hole 18. Further, a recess 19 that communicates with the through hole 18 is formed at the distal end of the proximal core shaft 13, and an optical element 100 of the optical pressure sensor 12 described later is accommodated in the space (housing) formed by the recess 19. A window portion (not shown) that communicates with the recess 19 is provided on the side surface of the distal end portion of the proximal core shaft 13, and the optical pressure sensor 12 measures the pressure by the blood flowing from the window portion into the recess 19. Note that the window portion is provided, for example, at two locations on the upper surface and the lower surface of the distal end portion of the proximal core shaft 13. The shape of the cross section (XY cross section) at each position of the proximal core shaft 13 can take any shape, but is, for example, circular or rectangular.

[0032] The distal end core shaft 15 is an elongated member extending along the central axis AX. The distal end core shaft 15 includes a tapered portion 15P whose outer shape gradually becomes smaller from the proximal end toward the distal end, a small-diameter portion 15D extending from the distal end of the tapered portion 15P toward the distal end with a substantially constant outer diameter, and a flange portion 15F provided on the proximal end side of the tapered portion 15P. The shape of the cross section (XY cross section) at each position of the distal end core shaft 15 can be any shape, for example, circular or rectangular. The flange portion 15F constituting the proximal end portion of the distal end core shaft 15 is joined to the distal end portion of the proximal end core shaft 13 by, for example, brazing or laser welding.

[0033] As materials for forming the proximal end core shaft 13 and the distal end core shaft 15, for example, stainless steel, Ni-Ti alloy, piano wire, etc. are used.

[0034] The coil body 16 is a hollow cylindrical coil-shaped member in which one or a plurality of wires are wound around the outer periphery of the distal end core shaft 15. Each wire constituting the coil body 16 may be composed of a single wire element or a stranded wire in which a plurality of wire elements are twisted together. The outer diameter of the coil body 16 is substantially constant from the proximal end to the distal end. The proximal end portion of the coil body 16 is joined to the flange portion 15F constituting the proximal end portion of the distal end core shaft 15 by, for example, brazing or laser welding. Also, the distal end portion of the coil body 16 is joined to the distal end portion of the distal end core shaft 15 via a distal end side joint portion 17. Note that the distal end side joint portion 17 constitutes the foremost end portion of the pressure sensor-equipped guide wire 10, and its outer peripheral surface is a smooth surface (for example, a substantially hemispherical surface).

[0035] As materials for forming the coil body 16, for example, radiation-transmissive materials such as stainless steel, Ni-Ti alloy, and piano wire, or radiation-opaque materials such as platinum, gold, tungsten, or their alloys are used. Further, as materials for forming the tip-side joint portion 17, for example, metal solders (Au-Sn alloy, Sn-Ag alloy, Sn-Pb alloy, Pb-Ag alloy, etc.), brazing materials (aluminum alloy brazing, silver brazing, gold brazing, etc.), adhesives (epoxy-based adhesives, etc.), etc. are used.

[0036] A-2. Configuration of the optical pressure sensor 12: Next, the configuration of the optical pressure sensor 12 provided in the guide wire 10 with a pressure sensor will be described. FIG. 2 is an explanatory diagram showing the configuration of the optical pressure sensor 12. FIG. 2 shows the configuration of the longitudinal section (YZ section) of the tip portion of the optical pressure sensor 12.

[0037] The optical pressure sensor 12 of the present embodiment is a Fabry-Perot interference type pressure sensor. As shown in FIGS. 1 and 2, the optical pressure sensor 12 includes an optical element 100 and an optical transmission medium 200 attached to the optical element 100.

[0038] As shown in FIG. 2, the optical element 100 is a substantially cylindrical box body in which a sealed space 108 called a cavity is formed inside. More specifically, the optical element 100 is composed of a base-end side member 110 and a tip-end side member 120. The base-end side member 110 is a bottomed cylindrical member. That is, the base-end side member 110 has a substantially disc-shaped plate portion 111 that is substantially orthogonal to the central axis AX, and a side wall portion 116 that extends a predetermined length from the peripheral edge of the plate portion 111 toward the tip end side. The side wall portion 116 is continuously formed over the entire circumference of the peripheral edge of the plate portion 111. Further, the tip-end side member 120 is a substantially disc-shaped member that is substantially orthogonal to the central axis AX. In the present embodiment, the outer diameter of the base-end side member 110 and the outer diameter of the tip-end side member 120 are substantially the same. In the present embodiment, the base-end side member 110 is an example of the first member in the claims, the tip-end side member 120 is an example of the second member in the claims, and the entire tip-end side member 120 is an example of the plate portion of the second member in the claims.

[0039] The peripheral region (hereinafter referred to as "sidewall facing region 122P") on the proximal end surface of the distal end side member 120 (the surface on the proximal end side member 110 side, hereinafter referred to as "proximal end surface 122") and the entire distal end surface 117 of the sidewall portion 116 of the proximal end side member 110 face each other in the Z-axis direction and are joined to each other via a later-described proximal end side reflective film 101 and a distal end side reflective film 102 that function as a bonding material. Thereby, the proximal end side member 110 and the distal end side member 120 are joined to each other. Inside the optical element 100 constituted by the joined proximal end side member 110 and distal end side member 120, a substantially cylindrical sealed space 108 defined by the plate-like portion 111 and the sidewall portion 116 of the proximal end side member 110 and the distal end side member 120 is formed. The inside of the sealed space 108 is a vacuum. In the present embodiment, the entire distal end surface 117 of the sidewall portion 116 of the proximal end side member 110 is an example of the first member side facing region in the claims, and the sidewall facing region 122P of the proximal end surface 122 of the distal end side member 120 is an example of the second member side facing region in the claims.

[0040] The distal end side member 120 is a very thin (for example, about 0.5 μm to 10 μm thick) plate-like member. Therefore, a portion of the distal end side member 120 that is not joined to the distal end surface 117 of the sidewall portion 116 of the proximal end side member 110 (that is, the portion facing the sealed space 108) constitutes a diaphragm portion 128 that deforms (buckles) due to external pressure.

[0041] As the materials for forming the base end side member 110 and the tip end side member 120, for example, silicon, quartz glass, borosilicate glass, etc. can be used. The base end side member 110 and the tip end side member 120 may each be entirely formed of the same material, or may be formed of different materials for each part. Also, the material for forming the base end side member 110 and the material for forming the tip end side member 120 may be the same material, or may be different materials from each other. Note that the materials for forming the base end side member 110 and the tip end side member 120 are preferably materials with a low coefficient of thermal expansion and a low elastic modulus from the viewpoint of suppressing the temperature drift of the optical pressure sensor 12. Also, the material for forming the base end side member 110 is preferably a material with high light transmittance. Also, the material for forming the base end side member 110 and the material for forming the tip end side member 120 preferably have similar coefficients of thermal expansion. From the above viewpoints, the materials for forming the base end side member 110 and the tip end side member 120 are preferably the same material as each other, and for example, preferably both are quartz glass.

[0042] In the optical element 100, two reflection films facing each other (directly facing) with the sealed space 108 interposed therebetween are formed. More specifically, a base end side reflection film 101 is formed on the surface of the plate-like portion 111 of the base end side member 110 facing the sealed space 108 (hereinafter referred to as the "bottom surface 114"). The base end side reflection film 101 is configured to reflect a part of the light transmitted by the light transmission medium 200 and transmit the remaining part. In the present embodiment, the base end side reflection film 101 is formed over the entire bottom surface 114 of the plate-like portion 111 of the base end side member 110. Also, in the present embodiment, the base end side reflection film 101 is formed not only on the bottom surface 114 but also on the inner peripheral surface of the side wall portion 116. In the present embodiment, the base end side reflection film 101 is an example of the first reflection film in the claims.

[0043] Further, on the region of the base end side surface 122 of the distal end side member 120 that faces the sealed space 108 (the region surrounded by the above-described side wall facing region 122P, hereinafter referred to as the "space facing region 122C"), a distal end side reflective film 102 is formed. The distal end side reflective film 102 is configured to reflect at least a part of the light transmitted by the optical transmission medium 200. In the present embodiment, the distal end side reflective film 102 is formed over the entire space facing region 122C on the base end side surface 122 of the distal end side member 120. Note that the space facing region 122C on the base end side surface 122 of the distal end side member 120 is, in other words, the surface of the diaphragm portion 128 that faces the sealed space 108. Therefore, it can be said that the distal end side reflective film 102 is formed over the entire surface of the diaphragm portion 128 that faces the sealed space 108. Further, in the present embodiment, the distal end side reflective film 102 is continuously formed from the space facing region 122C on the base end side surface 122 of the distal end side member 120 over the entire side wall facing region 122P. That is, in the present embodiment, the distal end side reflective film 102 is formed over the entire base end side surface 122 of the distal end side member 120. In the present embodiment, the distal end side reflective film 102 is an example of the second reflective film in the claims, the space facing region 122C on the base end side surface 122 of the distal end side member 120 is an example of the first region in the claims, and the side wall facing region 122P on the base end side surface 122 of the distal end side member 120 is an example of the second region in the claims.

[0044] The base end side reflective film 101 and the distal end side reflective film 102 are formed in a film shape that is substantially orthogonal to the central axis AX and face each other (face directly) with the sealed space 108 therebetween. Hereinafter, the distance between the base end side reflective film 101 and the distal end side reflective film 102 (that is, the height of the sealed space 108 along the central axis AX) is referred to as the cavity length Lc.

[0045] The thickness T1 of the base-end side reflective film 101 and the thickness T2 of the tip-end side reflective film 102 are, for example, about 1 nm to 50 nm. However, in the present embodiment, among the base-end side reflective film 101 and the tip-end side reflective film 102, the thickness T2 of the tip-end side reflective film 102, which is the reflective film farther from the optical transmission medium 200, is thicker than the thickness T1 of the base-end side reflective film 101, which is the reflective film closer to the optical transmission medium 200. Note that in this specification, the thickness T1 of the base-end side reflective film 101 and the thickness T2 of the tip-end side reflective film 102 mean the respective thicknesses at locations other than the joint surface between the base-end side member 110 and the tip-end side member 120.

[0046] The forming materials of the base-end side reflective film 101 and the tip-end side reflective film 102 are metals. As such metals, for example, metals containing at least one of Si, SiC, Al, Cu, Cr, Ni, Ti, and Au can be used. In the present embodiment, the base-end side reflective film 101 and the tip-end side reflective film 102 are formed of the same material. Note that the forming materials of the base-end side reflective film 101 and the tip-end side reflective film 102 are preferably materials having a low coefficient of thermal expansion and a low elastic modulus from the viewpoint of suppressing the temperature drift of the optical pressure sensor 12, and are preferably materials having a high reflectance from the viewpoint of enhancing the reflection intensity. The forming materials and thicknesses of the base-end side reflective film 101 and the tip-end side reflective film 102 are selected according to the optical characteristics required for the optical pressure sensor 12.

[0047] The optical transmission medium 200 is a long member for transmitting light, and in the present embodiment, it is constituted by an optical fiber. The tip of the optical transmission medium 200 is attached to the surface (hereinafter referred to as the "back surface 113") of the plate-like portion 111 of the base-end side member 110 of the optical element 100, which is opposite to the bottom surface 114. Further, as shown in FIG. 1, the base end of the optical transmission medium 200 reaches the base end of the base-end side core shaft 13.

[0048] As shown in Fig. 1, a light source 21, a spectroscope 22, and a console 23 are connected to an optical transmission medium 200. The light source 21 is a device that emits light toward the optical transmission medium 200. The spectroscope 22 is a device that splits the light incident from the optical transmission medium 200 and measures the intensity of each wavelength. The console 23 is a device that controls the light source 21 and the spectroscope 22 and converts the intensity signal of each wavelength input from the spectroscope 22 into an external pressure value.

[0049] A-3. Operation of the optical pressure sensor 12: Next, the operation of the optical pressure sensor 12 will be described. Fig. 3 is an explanatory diagram showing the operation of the optical pressure sensor 12. Fig. 3 shows the configuration of the longitudinal section (YZ section) of the tip of the optical pressure sensor 12 in a state where the diaphragm portion 128 is deformed.

[0050] As shown in Figs. 2 and 3, the diaphragm portion 128 of the optical pressure sensor 12 deforms (bends) in response to an external pressure P. When the diaphragm portion 128 deforms, the distance (cavity length Lc) between the base-end side reflective film 101 and the tip-end side reflective film 102 provided on the optical element 100 changes. More specifically, the higher the external pressure P, the greater the deformation of the diaphragm portion 128 and the smaller the value of the cavity length Lc.

[0051] As shown by the white arrows in Figs. 2 and 3, at least a part of the light 40 emitted from the light source 21 (Fig. 1) toward the optical transmission medium 200 passes through the plate-like portion 111 and the base-end side reflective film 101 of the base-end side member 110 of the optical element 100 and enters the sealed space 108. The light 40 that has entered the sealed space 108 undergoes multiple reflections between the base-end side reflective film 101 and the tip-end side reflective film 102. During this multiple reflection, light interference occurs. The interference peak wavelength at this time changes according to the cavity length Lc, that is, the external pressure P. The correspondence between the interference peak wavelength and the external pressure P is preset and stored in the console 23.

[0052] At least a part of the light 40 that has undergone multiple reflections in the sealed space 108 of the optical element 100 passes through the base-end side reflective film 101 and the plate-like portion 111 of the base-end side member 110, returns again into the optical transmission medium 200, and is input into the spectroscope 22 via the optical transmission medium 200. In the spectroscope 22, the interference peak wavelength of the input light is measured, and in the console 23, the external pressure P is measured based on the interference peak wavelength. The measured value of the external pressure P is displayed, for example, on a display unit provided in the console 23.

[0053] A-4. Manufacturing method of the optical pressure sensor 12: Next, the manufacturing method of the optical pressure sensor 12 will be described. FIG. 4 is a flowchart showing the manufacturing method of the optical pressure sensor 12, and FIG. 5 is an explanatory diagram schematically showing the manufacturing method of the optical pressure sensor 12.

[0054] First, the base-end side member 110 and the tip-end side member 120 are prepared (S110, refer to column A of FIG. 5, hereinafter referred to as the "preparation step"). Note that the base-end side member 110 can be manufactured, for example, by performing anisotropic etching on a substantially columnar member to form a recess 118 for forming the sealed space 108. The step of S110 (preparation step) is an example of the first step in the claims.

[0055] Next, the surfaces of the base-end side member 110 and the tip-end side member 120 are polished (S120, hereinafter referred to as the "polishing step"). The polishing step is performed, for example, by chemical mechanical polishing (CMP). Further, the polishing step is performed at least on the joint surface between the base-end side member 110 and the tip-end side member 120. That is, the polishing step is performed at least on the tip surface 117 of the side wall portion 116 of the base-end side member 110 and the side wall facing region 122P of the base-end side surface 122 of the tip-end side member 120. Note that the polishing step may be performed on other surface regions. Further, the polishing step is performed so that the surface roughness Sa of the surface to be polished becomes less than 50 nm. Note that it is more preferable that the polishing step is performed so that the surface roughness Sa becomes less than 10 nm, and it is even more preferable that the polishing step is performed so that the surface roughness Sa becomes less than 1 nm. The surface roughness Sa referred to here is the arithmetic mean height represented by the following formula (1). In the following formula (1), Z(x, y) is the height at the coordinates (x, y), and A is the area in the xy plane. Among the steps of S120 (polishing step), the step of polishing the tip surface 117 of the side wall portion 116 of the base-end side member 110 is an example of the fifth step in the claims, and the step of polishing the side wall facing region 122P of the base-end side surface 122 of the tip-end side member 120 is an example of the sixth step in the claims.

Number

[0056] Next, a base-end side reflective film 101 is formed on the surface of the base-end side member 110 and a tip-end side reflective film 102 is formed on the surface of the tip-end side member 120 under a vacuum condition where the temperature is not lower than -10°C and not higher than 200°C and the pressure is lower than the standard atmospheric pressure (S130, see column B of FIG. 5, hereinafter referred to as the "film forming step"). The base-end side reflective film 101 and the tip-end side reflective film 102 are formed, for example, by electron beam evaporation. The formation range of the base-end side reflective film 101 on the base-end side member 110 includes at least the entire bottom surface 114 of the plate-like portion 111 and the entire front end surface 117 of the side wall portion 116. In the present embodiment, the base-end side reflective film 101 is also formed on the inner peripheral surface of the side wall portion 116. On the other hand, the formation range of the tip-end side reflective film 102 on the tip-end side member 120 is the entire side wall facing region 122P and the entire space facing region 122C which is the region surrounded by the side wall facing region 122P on the base-end side surface 122 of the tip-end side member 120. That is, in the present embodiment, the formation range of the tip-end side reflective film 102 on the tip-end side member 120 is the entire base-end side surface 122. Among the steps of S130 (film forming step), the step of forming the base-end side reflective film 101 is an example of the second step in the claims, and the step of forming the tip-end side reflective film 102 is an example of the third step in the claims.

[0057] The materials for forming the base-end side reflective film 101 and the tip-end side reflective film 102 are metals, preferably metals containing at least one of Si, SiC, Al, Cu, Cr, Ni, Ti, and Au. Also, in the present embodiment, the material for forming the base-end side reflective film 101 and the material for forming the tip-end side reflective film 102 are the same as each other. Further, the formation of the base-end side reflective film 101 and the formation of the tip-end side reflective film 102 are both carried out under a vacuum condition where the temperature is not lower than -10°C and not higher than 200°C and the pressure is lower than the standard atmospheric pressure. However, the formation of each reflective film may be carried out in one chamber, or may be carried out independently in individual chambers. The formation environment of the base-end side reflective film 101 and the tip-end side reflective film 102 is more preferably a vacuum of 10 -1 PA or less, and 10 -3It is more preferable that the vacuum is below PA. Note that the lower limit of the pressure in the formation environment of the base-end side reflective film 101 and the tip-end side reflective film 102 is a value determined by the device limit. Further, the formation environment of the base-end side reflective film 101 and the tip-end side reflective film 102 is more preferably 0°C or higher and 100°C or lower, and even more preferably 10°C or higher and 30°C or lower. Also, it is preferable that no heating is performed during the formation of the base-end side reflective film 101 and the tip-end side reflective film 102. The film thicknesses of the base-end side reflective film 101 and the tip-end side reflective film 102 are, for example, about 1 nm to 50 nm. However, in the present embodiment, the thickness T2 of the tip-end side reflective film 102 is thicker than the thickness T1 of the base-end side reflective film 101.

[0058] Next, in a vacuum of -10°C or higher, 200°C or lower, and less than standard atmospheric pressure, the tip surface 117 of the side wall portion 116 of the base-end side member 110 on which the base-end side reflective film 101 is formed and the side wall opposing region 122P of the base-end side surface 122 of the tip-end side member 120 on which the tip-end side reflective film 102 is formed are brought into contact with each other, and the base-end side member 110 and the tip-end side member 120 are joined to obtain the optical element 100 (S140, see column C of FIG. 5, hereinafter referred to as the "joining step"). Thus, in the present embodiment, the joining of the base-end side member 110 and the tip-end side member 120 is realized by atomic diffusion bonding. Atomic diffusion bonding is a bonding method in which a bonding thin film is formed under vacuum and two members are bonded by utilizing its surface energy and atomic rearrangement phenomenon. In atomic diffusion bonding, members formed of any material (homogeneous material members or heterogeneous material members) can be bonded at a relatively low temperature. In the present embodiment, the base-end side reflective film 101 and the tip-end side reflective film 102 are also used as the bonding thin films in atomic diffusion bonding. That is, among the base-end side reflective film 101, the portion formed on the tip surface 117 of the side wall portion 116 of the base-end side member 110, and among the tip-end side reflective film 102, the portion formed on the side wall opposing region 122P of the base-end side surface 122 of the tip-end side member 120 do not function as a reflective film (mirror), but function as a bonding thin film for joining the base-end side member 110 and the tip-end side member 120. The step of S140 (joining step) is an example of the fourth step in the claims.

[0059] Note that the bonding process is carried out under a vacuum of not less than -10°C, not more than 200°C, and less than standard atmospheric pressure. However, it may be carried out in the same chamber following the film formation of the base-end side reflective film 101 and / or the tip-end side reflective film 102, or it may be carried out in the chamber again after being once taken out of the chamber after the film formation of the reflective film. Also, the environment of the bonding process is preferably a vacuum of 10 -1 PA or less. Further, the environment of the bonding process is more preferably from 0°C to 100°C, and even more preferably from 10°C to 30°C. Also, in the bonding process, after overlapping the base-end side member 110 and the tip-end side member 120, a predetermined load (for example, a load of about 1 t) may be applied to the laminate of the base-end side member 110 and the tip-end side member 120.

[0060] Finally, an optical transmission medium 200 is attached to the optical element 100 (S150, hereinafter referred to as the "attachment process"). More specifically, the optical transmission medium 200 is attached to the back surface 113 of the plate-like portion 111 of the base-end side member 110. The attachment of the optical transmission medium 200 is performed, for example, by an optical adhesive or fusion splicing. The process of S150 (attachment process) is an example of the seventh process in the claims. Mainly by the above processes, the optical pressure sensor 12 of the present embodiment can be manufactured.

[0061] Note that the manufacturing method of one optical pressure sensor 12 has been described above, but a plurality of optical pressure sensors 12 can also be manufactured simultaneously. FIG. 6 is an explanatory diagram schematically showing a method of manufacturing a plurality of optical pressure sensors 12 simultaneously. FIG. 6 schematically shows a method of manufacturing six optical pressure sensors 12 simultaneously. Hereinafter, the method of manufacturing a plurality of optical pressure sensors 12 simultaneously will be briefly described centering on the points different from the method of manufacturing one optical pressure sensor 12 described above.

[0062] First, as shown in column A of FIG. 6, a tip-side member material 120Z, which is the material of the tip-side member 120, is prepared, and a protective substrate 60 is bonded to the tip-side member material 120Z for protecting the tip-side member 120 during processing. The tip-side member material 120Z is, for example, a flat plate of quartz glass, and the protective substrate 60 is, for example, a flat plate of silicon. The bonding between the tip-side member material 120Z and the protective substrate 60 can be performed, for example, by atomic diffusion bonding.

[0063] Next, as shown in column B of FIG. 6, a base-side member material 110Z, which is the material of the base-side member 110, is prepared, and, for example, by etching, recesses 118 (six in number) corresponding to the number of optical pressure sensors 12 to be fabricated are formed. The base-side member material 110Z is, for example, a flat plate of quartz glass. Next, a base-side reflective film 101 is formed on the surface of the base-side member material 110Z and the bottom surfaces 114 (see column A of FIG. 5) of the respective recesses 118, a tip-side reflective film 102 is formed on the surface of the tip-side member material 120Z, and the base-side member material 110Z and the tip-side member material 120Z are overlapped. As a result, as shown in column C of FIG. 6, the base-side member material 110Z and the tip-side member material 120Z are bonded by atomic diffusion bonding, and a laminate of the base-side member material 110Z, the tip-side member material 120Z, and the protective substrate 60 is obtained.

[0064] Next, by performing a cutting process on the laminate of the base-end side member material 110Z, the tip-end side member material 120Z, and the protective substrate 60, a laminate of a predetermined number (six) of optical elements 100 composed of the base-end side member 110 and the tip-end side member 120 and the protective substrate 60 is obtained (see column D of FIG. 6). Next, the protective substrate 60 is removed from each of the obtained laminates to obtain the optical elements 100 (see column E of FIG. 6). Finally, the optical transmission medium 200 is attached to the optical elements 100 (see column F of FIG. 6). Through the above steps, a plurality (six) of optical pressure sensors 12 can be manufactured simultaneously. Note that the removal of the protective substrate 60 may be performed after the optical transmission medium 200 is attached to the laminate (the optical element 100 with the protective substrate 60). Also, when silicon is used as the material for forming the protective substrate 60, if silicon is used as the material for forming the base-end side reflective film 101 and the tip-end side reflective film 102, the base-end side reflective film 101 and the tip-end side reflective film 102 may be removed when the protective substrate 60 is removed. In this case, Ti or Al may be used as the material for forming the base-end side reflective film 101 and the tip-end side reflective film 102.

[0065] A-5. Effects of this Embodiment: As described above, the optical pressure sensor 12 that constitutes the guide wire 10 with a pressure sensor of the present embodiment includes a base end side member 110 and a tip end side member 120 that constitute the optical element 100, and an optical transmission medium 200. The base end side member 110 has a plate-shaped portion 111. Further, the tip end side member 120 functions as a plate-shaped portion as a whole. The base end side member 110 and the tip end side member 120 are joined to each other in a posture where the tip end side member 120 and the plate-shaped portion 111 of the base end side member 110 face each other. The base end side member 110 has a side wall portion 116 that extends from the plate-shaped portion 111 and whose tip surface is joined to the surface of the tip end side member 120. A sealed space 108 is defined by the plate-shaped portion 111 and the side wall portion 116 of the base end side member 110 and the tip end side member 120. Further, the optical transmission medium 200 is attached to the surface (back surface 113) of the plate-shaped portion 111 of the base end side member 110 on the side opposite to the surface (bottom surface 114) on the sealed space 108 side. A base end side reflection film 101 that reflects the light transmitted by the optical transmission medium 200 is formed on the bottom surface 114, which is the surface of the plate-shaped portion 111 of the base end side member 110 facing the sealed space 108. The base end side surface 122, which is the surface of the tip end side member 120 on the base end side member 110 side, includes a space facing region 122C facing the sealed space 108 and a side wall facing region 122P facing the tip surface 117 of the side wall portion 116 of the base end side member 110. A tip end side reflection film 102 that reflects the light transmitted by the optical transmission medium 200 is formed on the entire space facing region 122C.

[0066] Thus, in the optical pressure sensor 12 of the present embodiment, the tip end side reflection film 102 is formed on the entire space facing region 122C of the base end side surface 122 of the tip end side member 120. Therefore, according to the optical pressure sensor 12 of the present embodiment, as described below, the measurement accuracy of the optical pressure sensor can be sufficiently improved.

[0067] FIG. 7 is an explanatory diagram showing the configuration of the optical pressure sensor 12X of the comparative example. In the optical pressure sensor 12X of the comparative example, the tip-side reflective film 102 is formed not on the entire space-facing region 122C on the proximal-end surface 122 of the tip-side member 120 but only on a part of the central portion, and the tip-side reflective film 102 is not formed on the peripheral portion of the space-facing region 122C. This is because, when manufacturing the optical pressure sensor 12X of the comparative example, after forming the tip-side reflective film 102 on the tip-side member 120 by, for example, vapor deposition or sputtering, the tip-side member 120 and the proximal-end side member 110 are joined using, for example, a method by melting or a method by Au—Sn soldering. That is, in this comparative example, in order to prevent a joining defect from occurring due to the formation of the tip-side reflective film 102 on the joining surface between the tip-side member 120 and the proximal-end side member 110, the formation of the tip-side reflective film 102 on the peripheral portion of the space-facing region 122C is avoided, and the tip-side reflective film 102 is formed only on the central portion of the space-facing region 122C. Note that, in the optical pressure sensor 12X of the comparative example, similarly, the proximal-end side reflective film 101 is formed not on the entire bottom surface 114 of the plate-shaped portion 111 of the proximal-end side member 110 but only on a part of the central portion, and the proximal-end side reflective film 101 is not formed on the peripheral portion of the bottom surface 114.

[0068] As described above, in the optical pressure sensor 12X of the comparative example, the tip-side reflective film 102 is formed not on the entire space-facing region 122C on the proximal-end surface 122 of the tip-side member 120 but only on a part of the central portion. Therefore, in the optical pressure sensor 12X of the comparative example, the light reflection intensity by the tip-side reflective film 102 in the sealed space 108 cannot be sufficiently improved. Further, in the optical pressure sensor 12X of the comparative example, a displacement in the formation position of the tip-side reflective film 102 occurs in the space-facing region 122C of the proximal-end surface 122, and there is a possibility that the background of the interference waveform increases or decreases due to the displacement. As a result, in the optical pressure sensor 12X of the comparative example, the measurement accuracy of the optical pressure sensor 12X cannot be sufficiently improved.

[0069] In contrast, as shown in FIGS. 2 and 3, in the optical pressure sensor 12 of the present embodiment, the tip-side reflective film 102 is formed over the entire space-facing region 122C on the proximal-end surface 122 of the tip-side member 120. Therefore, the light reflection intensity by the tip-side reflective film 102 can be sufficiently improved, and the occurrence of displacement in the formation position of the tip-side reflective film 102 in the space-facing region 122C of the proximal-end surface 122 can be avoided. Therefore, according to the optical pressure sensor 12 of the present embodiment, the measurement accuracy of the optical pressure sensor 12 can be sufficiently improved.

[0070] Further, in the optical pressure sensor 12 of the present embodiment, among the proximal-end side reflective film 101 and the tip-side reflective film 102, the thickness T2 of the tip-side reflective film 102, which is the reflective film farther from the light transmission medium 200, is thicker than the thickness T1 of the proximal-end side reflective film 101, which is the reflective film closer to the light transmission medium 200. Therefore, it is possible to suppress the light that undergoes multiple reflections in the sealed space 108 from passing through the tip-side reflective film 102. If the light that undergoes multiple reflections in the sealed space 108 passes through the tip-side reflective film 102, the light reaches the tip surface of the tip-side member 120 through the inside of the tip-side member 120, is reflected by the tip surface, and returns to the sealed space 108 again. The light thus returned affects the peak value of the interference wavelength of the multiple reflections in the sealed space 108, and as a result, the measurement accuracy of the optical pressure sensor 12 may decrease. According to the optical pressure sensor 12 of the present embodiment, since it is possible to suppress the light that undergoes multiple reflections in the sealed space 108 from passing through the tip-side reflective film 102, it is possible to suppress a decrease in the measurement accuracy of the optical pressure sensor 12. Further, in the optical pressure sensor 12 of the present embodiment, since the thickness T1 of the proximal-end side reflective film 101 can be made relatively thin, the amount of light passing through the proximal-end side reflective film 101 and reaching the inside of the sealed space 108 can be increased. As a result, the peak value of the interference wavelength of the multiple reflections can be increased, and the measurement accuracy of the optical pressure sensor 12 can be improved.

[0071] In the optical pressure sensor 12 of the present embodiment, it is preferable that the base end side member 110 and the tip end side member 120 are formed of the same material. By doing so, the difference in the coefficient of thermal expansion between the base end side member 110 and the tip end side member 120 can be reduced, and it is possible to suppress a decrease in the measurement accuracy of the optical pressure sensor 12 due to the difference in the coefficient of thermal expansion.

[0072] Further, in the optical pressure sensor 12 of the present embodiment, the portion of the tip end side member 120 facing the sealed space 108 constitutes a diaphragm portion 128 that deforms by an external pressure. Therefore, in the optical pressure sensor 12 of the present embodiment, the tip end side reflection film 102 is formed on the entire surface of the diaphragm portion 128 facing the sealed space 108. Therefore, as will be described below, it is possible to suppress the diaphragm portion 128 from being damaged or the durability of the diaphragm portion 128 from decreasing, and it is possible to suppress a decrease in the measurement accuracy of the optical pressure sensor 12.

[0073] That is, in the optical pressure sensor 12X of the comparative example, since the tip end side reflection film 102 is formed only on a part of the central portion of the surface (space facing region 122C) of the diaphragm portion 128 facing the sealed space 108, the edge E of the tip end side reflection film 102 is located on the diaphragm portion 128. Therefore, when the diaphragm portion 128 deforms, stress concentrates at the position of the edge E of the tip end side reflection film 102, and the diaphragm portion 128 may be damaged. In addition, residual stress generated during the formation of the reflection film often occurs in the tip end side reflection film 102 of the diaphragm portion 128, and since the residual stress concentrates at the position of the edge E of the tip end side reflection film 102, the durability of the diaphragm portion 128 may decrease. Furthermore, when the external temperature changes, thermal stress caused by the difference in thermal expansion between the diaphragm portion 128 and the tip end side reflection film 102 concentrates at the position of the edge E of the tip end side reflection film 102, so that the diaphragm portion 128 is likely to deform, and as a result, there is a possibility that the measurement accuracy (temperature drift) of the optical pressure sensor 12 decreases.

[0074] In contrast, in the optical pressure sensor 12 of the present embodiment, since the tip-side reflective film 102 is formed on the entire surface of the diaphragm portion 128 facing the sealed space 108, the edge E of the tip-side reflective film 102 does not lie on the diaphragm portion 128. Therefore, according to the optical pressure sensor 12 of the present embodiment, it is possible to suppress stress from concentrating at the position of the edge E of the tip-side reflective film 102 when the diaphragm portion 128 is deformed, and it is possible to suppress the diaphragm portion 128 from being damaged. Further, even if residual stress concentrates at the position of the edge E of the tip-side reflective film 102, it is possible to suppress a decrease in the durability of the diaphragm portion 128. Furthermore, even when the external temperature changes and thermal stress due to the difference in thermal expansion between the diaphragm portion 128 and the tip-side reflective film 102 concentrates at the position of the edge E of the tip-side reflective film 102, it is possible to avoid the diaphragm portion 128 from being easily deformed, and it is possible to suppress a decrease in the measurement accuracy (temperature drift) of the optical pressure sensor 12 from occurring.

[0075] Also, in the optical pressure sensor 12 of the present embodiment, the tip-side reflective film 102 is formed continuously from the space-facing region 122C of the base-end surface 122 in the tip-side member 120 to the side-wall facing region 122P. In other words, the tip-side reflective film 102 is formed continuously from the surface facing the sealed space 108 in the diaphragm portion 128 to the joint surface with the base-end member 110 in the tip-side member 120. Therefore, the edge E of the tip-side reflective film 102 is not located on the outer peripheral edge of the diaphragm portion 128, but is located on the outer peripheral side of the outer peripheral edge of the diaphragm portion 128. Accordingly, according to the optical pressure sensor 12 of the present embodiment, when the diaphragm portion 128 is deformed, it is possible to effectively suppress the concentration of stress at the position of the edge E of the tip-side reflective film 102, and it is possible to effectively suppress the breakage of the diaphragm portion 128. Further, even if residual stress is concentrated at the position of the edge E of the tip-side reflective film 102, it is possible to effectively suppress the reduction in the durability of the diaphragm portion 128. Furthermore, when the external temperature changes, even if thermal stress caused by the difference in thermal expansion between the diaphragm portion 128 and the tip-side reflective film 102 is concentrated at the position of the edge E of the tip-side reflective film 102, it is possible to effectively avoid the diaphragm portion 128 from being easily deformed, and it is possible to effectively suppress the occurrence of a decrease in the measurement accuracy (temperature drift) of the optical pressure sensor 12.

[0076] In addition, the manufacturing method of the optical pressure sensor 12 of the present embodiment includes a preparation step (S110), a film forming step (S130), and a bonding step (S140). The preparation step (S110) is a step of preparing a base end side member 110 and a tip end side member 120. The film forming step (S130) is performed under a vacuum of -10°C or higher, 200°C or lower, and less than standard atmospheric pressure. On the bottom surface 114, which is the surface of the plate-like portion 111 of the base end side member 110 facing the tip end side member 120, and on the region (the entire tip end surface 117) of the tip end surface 117 of the side wall portion 116 of the base end side member 110 that faces the tip end side member 120, a base end side reflective film 101 that is formed of a specific metal and reflects light is formed. Further, the film forming step (S130) is performed under a vacuum of -10°C or higher, 200°C or lower, and less than standard atmospheric pressure. On the side wall facing region 122P of the base end side surface 122 of the tip end side member 120 that faces the tip end surface 117 of the side wall portion 116 of the base end side member 110, and on the entire space facing region 122C surrounded by the side wall facing region 122P, a tip end side reflective film 102 that is formed of the above specific metal and reflects light is formed. The bonding step (S140) is a step of bonding the base end side member 110 and the tip end side member 120 by bringing the tip end surface 117 of the side wall portion 116 of the base end side member 110 on which the base end side reflective film 101 is formed into contact with the side wall facing region 122P of the base end side surface 122 of the tip end side member 120 on which the tip end side reflective film 102 is formed under a vacuum of -10°C or higher, 200°C or lower, and less than standard atmospheric pressure.

[0077] Thus, in the manufacturing method of the optical pressure sensor 12 of the present embodiment, since the base-end side member 110 and the tip-end side member 120 can be joined at a temperature that is not excessively high, i.e., -10°C or higher and 200°C or lower, it is possible to suppress the generation of thermal strain in each member during the manufacture of the optical pressure sensor 12. Further, since no melt or adhesive is used when joining the base-end side member 110 and the tip-end side member 120, it is possible to suppress a deterioration in the quality of the optical pressure sensor 12 caused by the outflow of the melt or adhesive. Furthermore, since the base-end side reflective film 101 and the tip-end side reflective film 102 can function as a joining material for joining the base-end side member 110 and the tip-end side member 120, it is possible to realize an improvement in manufacturing efficiency as compared with a manufacturing method in which the formation of the reflective film and the formation of the joining material are carried out as separate steps. Also, since there is no need to use an acid-based chemical when forming the base-end side reflective film 101 and the tip-end side reflective film 102, it is possible to suppress joining failure and a decrease in light transmissivity caused by roughening of the surfaces of the base-end side member 110 and the tip-end side member 120 due to the acid-based chemical.

[0078] In addition, the manufacturing method of the optical pressure sensor 12 of the present embodiment further includes a polishing step (S120). The polishing step (S120) includes a step of polishing the tip surface 117 of the side wall portion 116 of the base end side member 110 before the film forming step (S130). The polishing step (S120) also includes a step of polishing the side wall facing region 122P of the base end side surface 122 of the tip end side member 120 before the film forming step (S130). Therefore, according to the manufacturing method of the optical pressure sensor 12 of the present embodiment, the bonding strength between the tip surface 117 of the side wall portion 116 of the base end side member 110 and the base end side reflective film 101, and the bonding strength between the side wall facing region 122P of the base end side surface 122 of the tip end side member 120 and the tip end side reflective film 102 can be improved. As a result, the bonding strength between the base end side member 110 and the tip end side member 120 can be improved. Note that the polishing step (S120) is a step of polishing the tip surface 117 of the side wall portion 116 of the base end side member 110 and the side wall facing region 122P of the base end side surface 122 of the tip end side member 120 so that the surface roughness Sa is less than 50 nm. Therefore, according to the manufacturing method of the optical pressure sensor 12 of the present embodiment, the bonding strength between the tip surface 117 of the side wall portion 116 of the base end side member 110 and the base end side reflective film 101, and the bonding strength between the side wall facing region 122P of the base end side surface 122 of the tip end side member 120 and the tip end side reflective film 102 can be effectively improved. As a result, the bonding strength between the base end side member 110 and the tip end side member 120 can be effectively improved.

[0079] Further, the manufacturing method of the optical pressure sensor 12 of the present embodiment further includes an attachment step (S150) of attaching an optical transmission medium 200 to the back surface 113, which is the surface on the side opposite to the surface on the sealed space 108 side in the proximal end side member 110, after the bonding step (S140). Further, the film forming step (S130) is performed such that the thickness T2 of the distal end side reflective film 102, which is the reflective film farther from the optical transmission medium 200 in the state after the attachment step (S150) among the proximal end side reflective film 101 and the distal end side reflective film 102, is thicker than the thickness T1 of the proximal end side reflective film 101, which is the reflective film closer to the optical transmission medium 200. Therefore, according to the manufacturing method of the optical pressure sensor 12 of the present embodiment, in the manufactured optical pressure sensor 12, it is possible to suppress the light that undergoes multiple reflections in the sealed space 108 from passing through the distal end side reflective film 102, and it is possible to suppress a decrease in the measurement accuracy of the optical pressure sensor 12. Further, according to the manufacturing method of the optical pressure sensor 12 of the present embodiment, since the thickness T1 of the proximal end side reflective film 101 can be made relatively thin, the amount of light that passes through the proximal end side reflective film 101 and reaches the inside of the sealed space 108 can be increased. As a result, the peak value of the interference wavelength of multiple reflections can be increased, and the measurement accuracy of the optical pressure sensor 12 can be improved.

[0080] Further, for the specific metal, which is the forming material of the proximal end side reflective film 101 and the distal end side reflective film 102 formed in the film forming step (S130) of the manufacturing method of the optical pressure sensor 12 of the present embodiment, it is preferable to contain at least one of Si, SiC, Al, Cu, Cr, Ni, Ti, and Au. By doing so, the proximal end side member 110 and the distal end side member 120 can be more reliably joined at a temperature that is not excessively high, such as -10°C or higher and 200°C or lower.

[0081] Further, in the manufacturing method of the optical pressure sensor 12 of the present embodiment, it is preferable that the base-end side member 110 and the tip-end side member 120 are formed of the same material. By doing so, in the manufactured optical pressure sensor 12, the difference in the coefficient of thermal expansion between the base-end side member 110 and the tip-end side member 120 can be reduced, and it is possible to suppress a decrease in the measurement accuracy of the optical pressure sensor 12 due to the difference in the coefficient of thermal expansion.

[0082] B. Second Embodiment: FIG. 8 is an explanatory diagram schematically showing the configuration of the optical pressure sensor 12a in the second embodiment. Hereinafter, among the configurations of the optical pressure sensor 12a in the second embodiment, the same configurations as those of the optical pressure sensor 12 in the first embodiment described above will be denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0083] In the optical pressure sensor 12a in the second embodiment, the magnitude relationship between the thicknesses of the base-end side reflective film 101 and the tip-end side reflective film 102 is different from that of the optical pressure sensor 12 in the first embodiment. Specifically, in the optical pressure sensor 12a in the second embodiment, among the base-end side reflective film 101 and the tip-end side reflective film 102, the thickness T1 of the base-end side reflective film 101, which is the reflective film closer to the optical transmission medium 200, is thicker than the thickness T2 of the tip-end side reflective film 102, which is the reflective film farther from the optical transmission medium 200.

[0084] Thus, in the optical pressure sensor 12a of the second embodiment, among the base-end side reflective film 101 and the tip-end side reflective film 102, the thickness T1 of the base-end side reflective film 101, which is the reflective film closer to the optical transmission medium 200, is thicker than the thickness T2 of the tip-end side reflective film 102, which is the reflective film farther from the optical transmission medium 200. Therefore, the tip-end side reflective film 102 formed on the diaphragm portion 128, which is a very thin plate-like portion, can be made relatively thin, and the thermal stress caused by the difference in thermal expansion between the diaphragm portion 128 and the tip-end side reflective film 102 can be reduced. As a result, it is possible to suppress the occurrence of a decrease in the measurement accuracy (temperature drift) of the optical pressure sensor 12a due to the thermal stress.

[0085] C. Third Embodiment: FIG. 9 is an explanatory diagram schematically showing the configuration of the optical pressure sensor 12b in the third embodiment. Hereinafter, among the configurations of the optical pressure sensor 12b in the third embodiment, the same configurations as those of the optical pressure sensor 12 in the above-described first embodiment will be denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0086] In the optical pressure sensor 12b in the third embodiment, the configuration of the base-end side member 110 and the tip-end side member 120 constituting the optical element 100 is different from that of the optical pressure sensor 12 in the first embodiment. That is, in the optical pressure sensor 12b in the third embodiment, contrary to the above-described first embodiment, the base-end side member 110 is a substantially disc-shaped member, and the tip-end side member 120 is a bottomed cylindrical member.

[0087] More specifically, the tip-end side member 120 has a substantially disc-shaped plate portion 121 that is substantially orthogonal to the central axis AX, and a side wall portion 126 that extends from the peripheral edge portion of the plate portion 121 toward the base end side by a predetermined length. The side wall portion 126 is continuously formed over the entire circumference of the peripheral edge portion of the plate portion 121. The base-end side member 110 is a substantially disc-shaped member that is substantially orthogonal to the central axis AX. In the present embodiment, the tip-end side member 120 is an example of the first member in the claims, the base-end side member 110 is an example of the second member in the claims, and the entire base-end side member 110 is an example of the plate portion of the second member in the claims.

[0088] The region of the peripheral edge on the tip-side surface of the base-end side member 110 (the surface on the tip-side member 120 side, hereinafter referred to as the "tip-side surface 112") (hereinafter referred to as the "sidewall facing region 112P") and the entire tip surface 127 of the sidewall portion 126 of the tip-side member 120 face each other in the Z-axis direction and are joined to each other via the base-end side reflective film 101 and the tip-side reflective film 102 that function as a bonding material. Thereby, the base-end side member 110 and the tip-side member 120 are joined to each other. Inside the optical element 100 constituted by the base-end side member 110 and the tip-side member 120 joined to each other, a sealed space 108 defined by the plate-like portion 121 and the sidewall portion 126 of the tip-side member 120 and the base-end side member 110 is formed. The entire tip surface 127 of the sidewall portion 126 of the tip-side member 120 is an example of the first member-side facing region in the claims, and the sidewall facing region 112P of the tip-side surface 112 of the base-end side member 110 is an example of the second member-side facing region in the claims.

[0089] The central portion (the portion facing the sealed space 108) of the plate-like portion 121 of the tip-side member 120 constitutes a diaphragm portion 128 that is a very thin plate-like portion and deforms (deflects) due to external pressure.

[0090] Inside the optical element 100, two reflecting films facing each other (facing directly) with a sealed space 108 interposed therebetween are formed. More specifically, in the region of the tip-side surface 112 of the base-end-side member 110 facing the sealed space 108 (the region surrounded by the above-described side-wall facing region 112P, hereinafter referred to as "space facing region 112C"), a base-end-side reflecting film 101 is formed. The base-end-side reflecting film 101 is configured to reflect a part of the light transmitted by the optical transmission medium 200 and transmit the remaining part. In the present embodiment, the base-end-side reflecting film 101 is formed over the entire space facing region 112C on the tip-side surface 112 of the base-end-side member 110. Further, in the present embodiment, the base-end-side reflecting film 101 is continuously formed over the entire side-wall facing region 112P from the space facing region 112C on the tip-side surface 112 of the base-end-side member 110. That is, in the present embodiment, the base-end-side reflecting film 101 is formed over the entire tip-side surface 112 of the base-end-side member 110. The base-end-side reflecting film 101 is an example of the second reflecting film in the claims, the space facing region 112C on the tip-side surface 112 of the base-end-side member 110 is an example of the first region in the claims, and the side-wall facing region 112P on the tip-side surface 112 of the base-end-side member 110 is an example of the second region in the claims.

[0091] Also, on the surface of the plate-like portion 121 of the tip-side member 120 facing the sealed space 108 (hereinafter referred to as "bottom surface 124"), a tip-side reflecting film 102 is formed. The tip-side reflecting film 102 is configured to reflect at least a part of the light transmitted by the optical transmission medium 200. In the present embodiment, the tip-side reflecting film 102 is formed over the entire bottom surface 124 of the plate-like portion 121 of the tip-side member 120. Note that the bottom surface 124 of the plate-like portion 121 of the tip-side member 120 is, in other words, the surface of the diaphragm portion 128 facing the sealed space 108. Therefore, it can be said that the tip-side reflecting film 102 is formed over the entire surface of the diaphragm portion 128 facing the sealed space 108. Further, in the present embodiment, the tip-side reflecting film 102 is formed not only on the bottom surface 124 but also on the inner peripheral surface of the side-wall portion 126. The tip-side reflecting film 102 is an example of the first reflecting film in the claims.

[0092] The thickness T1 of the base-end side reflective film 101 and the thickness T2 of the tip-end side reflective film 102 are, for example, about 1 nm to 50 nm. However, in the present embodiment, among the base-end side reflective film 101 and the tip-end side reflective film 102, the thickness T2 of the tip-end side reflective film 102, which is the reflective film farther from the optical transmission medium 200, is thicker than the thickness T1 of the base-end side reflective film 101, which is the reflective film closer to the optical transmission medium 200.

[0093] The optical pressure sensor 12b in the third embodiment can be manufactured by the same method (see FIGS. 4 and 5) as the manufacturing method of the optical pressure sensor 12 in the first embodiment described above. However, as described above, in the optical pressure sensor 12b in the third embodiment, since the base-end side member 110 is a substantially disc-shaped member and the tip-end side member 120 is a bottomed cylindrical member, the manufacturing method is different in that regard.

[0094] Since the optical pressure sensor 12b in the third embodiment has the same configuration as the optical pressure sensor 12 in the first embodiment described above, similar to the optical pressure sensor 12 in the first embodiment, the maximum reflection intensity by the base-end side reflective film 101 can be obtained, and the occurrence of displacement of the formation position of the base-end side reflective film 101 in the space facing region 112C of the tip-end side surface 112 can be avoided, and the measurement accuracy of the optical pressure sensor 12b can be sufficiently improved.

[0095] Also, since the manufacturing method of the optical pressure sensor 12b in the third embodiment is the same method as the manufacturing method of the optical pressure sensor 12 in the first embodiment described above, it is possible to suppress the occurrence of thermal strain in each member during the manufacture of the optical pressure sensor 12b, suppress the deterioration of the quality of the optical pressure sensor 12b due to the outflow of the melt or the adhesive, and further realize the efficiency improvement in the manufacture of the optical pressure sensor 12b.

[0096] D. Modification example: The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified into various forms without departing from the gist thereof. For example, the following modifications are also possible.

[0097] The configuration of the guide wire 10 with the pressure sensor and the optical pressure sensor 12 constituting the same in the above-described embodiment is merely an example, and can be variously modified. FIG. 10 is an explanatory diagram schematically showing the configuration of the optical pressure sensor 12c of the first modification example. In the optical pressure sensor 12c of the first modification example shown in FIG. 10, the proximal end side reflective film 101 is formed on the entire bottom surface 114 of the plate-like portion 111 of the proximal end side member 110, but is not formed on the inner peripheral surface of the side wall portion 116. Thus, the proximal end side reflective film 101 does not necessarily have to be formed on the inner peripheral surface of the side wall portion 116 of the proximal end side member 110.

[0098] FIG. 11 is an explanatory diagram schematically showing the configuration of the optical pressure sensor 12d of the second modification example. In the optical pressure sensor 12d of the second modification example shown in FIG. 11, the inner peripheral surface of the side wall portion 116 of the proximal end side member 110 is inclined with respect to the central axis AX, and as a result, the diameter of the sealed space 108 becomes larger toward the distal end side. Such a configuration can be realized, for example, by performing isotropic etching on a substantially columnar member that is the forming material of the proximal end side member 110, and forming a concave portion having a smaller diameter closer to the side wall portion 116 as a concave portion for constituting the sealed space 108. Thus, the side wall portion 116 of the proximal end side member 110 does not necessarily have to be in the form of a wall parallel to the central axis AX, and any shape can be adopted as long as it is a wall extending from the plate-like portion 111 of the proximal end side member 110 toward the distal end side.

[0099] FIG. 12 is an explanatory diagram schematically showing the configuration of the optical pressure sensor 12e according to the third modification. In the optical pressure sensor 12e according to the third modification shown in FIG. 12, a convex portion 129 protruding toward the proximal end side is formed at the center of the proximal end side surface 122 of the distal end side member 120. As a result, the thickness of the central portion of the diaphragm portion 128 is increased. According to the optical pressure sensor 12e of the third modification shown in FIG. 12, even when the diaphragm portion 128 is deformed according to an external pressure, the central portion of the diaphragm portion 128 can maintain a state orthogonal to the central axis AX. Therefore, the surface of the distal end side reflective film 102 formed at the central portion of the diaphragm portion 128 can maintain a state orthogonal to the central axis AX. As a result, the reflection direction of light by the distal end side reflective film 102 can be maintained in a direction parallel to the central axis AX, and the measurement accuracy of the external pressure based on the interference peak wavelength of multiple reflections of light in the sealed space 108 can be improved.

[0100] In the above embodiment, the proximal end side member 110 is composed of the plate-like portion 111 and the side wall portion 116, but the proximal end side member 110 may have other portions in addition to the plate-like portion 111 and the side wall portion 116. Further, although the entire front end surface 117 of the side wall portion 116 of the proximal end side member 110 is joined to the distal end side member 120, only a partial region of the front end surface 117 of the side wall portion 116 of the proximal end side member 110 may be joined to the distal end side member 120. Further, in the above embodiment, the distal end side member 120 constitutes a plate-like portion as a whole, but the distal end side member 120 may have other portions in addition to the plate-like portion. Further, although the entire peripheral edge portion of the proximal end side surface 122 of the distal end side member 120 is joined to the proximal end side member 110, only a partial region of the peripheral edge portion of the proximal end side surface 122 of the distal end side member 120 may be joined to the proximal end side member 110.

[0101] In the above-described embodiment, the magnitude relationship between the thickness T1 of the proximal-side reflective film 101 and the thickness T2 of the distal-side reflective film 102 can be arbitrarily changed. For example, the thickness T1 of the proximal-side reflective film 101 and the thickness T2 of the distal-side reflective film 102 may be the same. Further, the proximal-side reflective film 101 and / or the distal-side reflective film 102 may have a multilayer structure. For example, the proximal-side reflective film 101 may be a two-layer structure of an Si layer and an Au layer, and the distal-side reflective film 102 may be a single Si layer. In this case, the side of the proximal-side reflective film 101 that contacts the distal-side reflective film 102 may be an Si layer so that the proximal-side reflective film 101 and the distal-side reflective film 102 function as bonding thin films for atomic diffusion bonding.

[0102] The manufacturing method of the optical pressure sensor 12 in the above-described embodiment is merely an example and can be variously modified. For example, in the manufacturing method of the optical pressure sensor 12 of the above-described embodiment, the polishing step (S120) is performed, but this polishing step may be omitted.

[0103] In the above-described embodiment, the pressure sensor-equipped guide wire 10 including the optical pressure sensor 12 has been described as an example. However, the optical pressure sensor 12 disclosed in this specification can be mounted not only on a guide wire but also on other types of medical devices and devices other than medical devices.

Explanation of Reference Numerals

[0104] 10: Guide wire with pressure sensor 12: Optical pressure sensor 13: Base-end side core shaft 15: Tip-end side core shaft 15D: Small-diameter part 15P: Taper part 15F: Flange part 16: Coil body 17: Tip-end side joint part 18: Through hole 19: Recess 21: Light source 22: Spectrometer 23: Console 60: Protection substrate 100: Optical element 101: Base-end side reflection film 102: Tip-end side reflection film 108: Sealed space 110: Base-end side member 110Z: Base-end side member material 111: Plate-like part 112: Tip-end side surface 112C: Space facing region 112P: Side wall facing region 113: Back surface 114: Bottom surface 116: Side wall part 117: Tip-end surface 118: Recess 120: Tip-end side member 120Z: Tip-end side member material 121: Plate-like part 122: Base-end side surface 122C: Space facing region 122P: Side wall facing region 124: Bottom surface 126: Side wall part 127: Tip-end surface 128: Diaphragm part 129: Protrusion 200: Optical transmission medium AX: Central axis E: Edge Lc: Cavity length

Claims

1. An optical pressure sensor, comprising a first member and a second member each having a plate-like portion, wherein the first member and the second member are joined to each other in a posture in which the two plate-like portions face each other, the first member has a side wall portion extending from the plate-like portion of the first member and having a tip surface joined to the surface of the plate-like portion of the second member, and a sealed space is defined by the two plate-like portions and the side wall portion, and a portion of the plate-like portion of the second member facing the sealed space constitutes a diaphragm portion that deforms by an external pressure, the first member and the second member; an optical transmission medium attached to a surface of one of the two plate-like portions on a side opposite to the surface on the sealed space side; and comprising: a first reflection film that reflects light transmitted by the optical transmission medium is formed on a surface of the plate-like portion of the first member facing the sealed space; the surface of the plate-like portion of the second member on the first member side includes a first region facing the sealed space and a second region facing the tip surface of the side wall portion of the first member, and a second reflection film that reflects light transmitted by the optical transmission medium is formed on the entire first region and is also formed continuously from the first region to the second region; an optical pressure sensor.

2. The optical pressure sensor according to claim 1, wherein, among the first reflection film and the second reflection film, the thickness of the reflection film farther from the optical transmission medium is thicker than the thickness of the reflection film closer to the optical transmission medium. an optical pressure sensor.

3. The optical pressure sensor according to claim 1, wherein, among the first reflection film and the second reflection film, the thickness of the reflection film closer to the optical transmission medium is thicker than the thickness of the reflection film farther from the optical transmission medium. an optical pressure sensor.

4. The optical pressure sensor according to any one of claims 1 to 3, wherein the first member and the second member are formed of the same material. an optical pressure sensor.

5. A first member and a second member each having a plate-like portion, wherein the first member and the second member are joined to each other with the two plate-like portions facing each other, and the first member has a side wall portion extending from the plate-like portion of the first member and having a tip surface joined to the surface of the plate-like portion of the second member, and a sealed space is defined by the two plate-like portions and the side wall portion, and a method for manufacturing an optical pressure sensor including the first member and the second member, A first step of preparing the first member and the second member; A second step of forming a first reflective film that is formed of a specific metal and reflects light on a surface of the plate-like portion of the first member facing the plate-like portion of the second member and a first member-side facing region of the tip surface of the side wall portion of the first member facing the plate-like portion of the second member under a vacuum of -10°C or higher, 200°C or lower, and less than standard atmospheric pressure; A third step of forming a second reflective film that is formed of the specific metal and reflects light on a second member-side facing region of the surface of the plate-like portion of the second member on the first member side facing the tip surface of the side wall portion of the first member and the entire region surrounded by the second member-side facing region under a vacuum of -10°C or higher, 200°C or lower, and less than standard atmospheric pressure; A fourth step of joining the first member and the second member by bringing the first member-side facing region of the first member on which the first reflective film is formed into contact with the second member-side facing region of the second member on which the second reflective film is formed under a vacuum of -10°C or higher, 200°C or lower, and less than standard atmospheric pressure; Comprising; A method for manufacturing an optical pressure sensor.

6. The method for manufacturing an optical pressure sensor according to claim 5, further comprising: A fifth step of polishing the first member-side facing region before the second step; A sixth step of polishing the second member-side facing region before the third step; Comprising; A method for manufacturing an optical pressure sensor.

7. The method for manufacturing an optical pressure sensor according to claim 6, wherein The fifth step is a step of polishing the first member-side facing region so that the surface roughness Sa is less than 50 nm; The sixth step is a step of polishing the second member-side facing region so that the surface roughness Sa is less than 50 nm. A method for manufacturing an optical pressure sensor.

8. A method for manufacturing an optical pressure sensor according to any one of claims 5 to 7, further comprising: a seventh step of attaching an optical transmission medium to a surface of one of the plate-like portions of the first member and the plate-like portion of the second member, which is opposite to the surface on the sealed space side, after the fourth step; the second step and the third step are performed such that the thickness of the reflection film, which is farther from the optical transmission medium in the state after the seventh step, among the first reflection film and the second reflection film, is thicker than the thickness of the reflection film, which is closer to the optical transmission medium; A method for manufacturing an optical pressure sensor.

9. A method for manufacturing an optical pressure sensor according to any one of claims 5 to 7, further comprising: a seventh step of attaching an optical transmission medium to a surface of one of the plate-like portions of the first member and the plate-like portion of the second member, which is opposite to the surface on the sealed space side, after the fourth step; the second step and the third step are performed such that the thickness of the reflection film, which is closer to the optical transmission medium in the state after the seventh step, among the first reflection film and the second reflection film, is thicker than the thickness of the reflection film, which is farther from the optical transmission medium; A method for manufacturing an optical pressure sensor.

10. A method for manufacturing an optical pressure sensor according to any one of claims 5 to 9, wherein the specific metal contains at least one of Si, SiC, Al, Cu, Cr, Ni, Ti, and Au; A method for manufacturing an optical pressure sensor.

11. A method for manufacturing an optical pressure sensor according to any one of claims 7 to 10, wherein the first member and the second member are formed of the same material; A method for manufacturing an optical pressure sensor.

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