JP2005037314A - Optical interference pressure sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical interference pressure sensor for solving problems that a mirror fluctuating with a diaphragm moved by pressure fluctuation causes a distortion in the mirror since the mirror is directly disposed on the diaphragm, that an excessive pressure breaks mirrors by bringing them into contact with each other, and the like. <P>SOLUTION: This optical interference pressure sensor comprises a pressure-fluctuated movable elastic body formed integral with or firm fixed to a fixed ring, a mirror mechanism A disposed on and firm fixed to the elastic body via a fixed seat, a fluid introduction tool for forming a fluid pressure chamber by sealing/firm-fixing or unifying the fixed ring and the elastic body, a fixed backboard firm fixed to the fixed ring on an opposite surface to the introduction tool, and a mirror mechanism B disposed on the fixed backboard side and parallel confronting the mirror mechanism A. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The optical interference pressure sensor according to the present invention relates to a pressure sensor that detects a positive pressure or a negative pressure of a fluid as optical interference light.

  Conventionally, mechanical pressure gauges using Bourdon tubes, bellows, diaphragms, etc., electronic pressure gauges using silicon diaphragms, ceramic diaphragms, semiconductor strain gauges, etc., optical interference pressure gauges using optical interference Many have been proposed.

Japanese Patent No. 3393370 describes a pressure sensor in which a half mirror is formed at the tip of an optical fiber and a reflective movable diaphragm unit is further fixed. Japanese Patent Application Laid-Open No. 2000-241270 describes an optical interference type diaphragm type pressure sensor using an optical fiber capable of detecting positive pressure and / or negative pressure.

  Conventional optical interference type pressure sensors have a mirror placed on a diaphragm that changes according to fluid pressure fluctuations, a half mirror placed on the opposite fixed part, and the projected light is reflected and transmitted by the surface of the half mirror. The reflected light is reflected by the diaphragm mirror, passes through the half mirror, and interferes with the first reflected light. In this conventional optical interference pressure sensor, the mirror is arranged directly on the diaphragm, and the diaphragm fluctuates together with the diaphragm that changes according to the pressure fluctuation, causing the mirror to be distorted. There is a problem that the mirror is brought into contact with the mirror due to excessive pressure and broken, or that the diaphragm is broken due to mechanical contact because the diaphragm is directly exposed. The present invention is to provide an optical interference type pressure sensor that solves these problems.

  A movable elastic body that is integrally formed with or fixed to a fixed ring and fluctuates in pressure, a mirror mechanism A that is arranged and fixed to the movable elastic body via a fixed base, and a fluid that is fixed or integrated with the fixed ring and the movable elastic body. A fluid introducing device forming a pressure chamber, a fixed back plate fixed to the fixing ring on the opposite surface of the fluid introducing device, and a mirror mechanism arranged on the side of the fixed back plate and facing the mirror mechanism A in parallel B is an optical interference type pressure sensor composed of B, since the mirror mechanism A is arranged via the fixed base, the mirror mechanism A is hardly distorted, and the movable elastic body as a diaphragm is protected by the fluid introduction tool. In addition, it is not destroyed by mechanical contact. Further, the optical interference type pressure sensor, wherein the mirror chamber surrounded by the movable elastic body, the fixed ring and the fixed back plate is hermetically sealed with a specific pressure (negative pressure, atmospheric pressure, positive pressure), or It is an optical interference type pressure sensor in which a mirror chamber surrounded by the movable elastic body, the fixed ring and the fixed back plate and an open path that opens to the outside are formed. The optical interference type pressure sensor has an optical fiber fixed to the fixed back plate. The mirror mechanism A is a total reflection type, the mirror mechanism B is a semi-reflection type, and is an optical interference type pressure sensor facing in parallel with a gap. The mirror mechanism B is an optical interference type pressure sensor in which a thin film is formed at the tip of an optical fiber. Further, the optical interference type pressure sensor has a mirror protection dam formed in the mirror chamber, and the mirror and the mirror can be prevented from being damaged due to excessive pressure.

Details regarding the optical interference type pressure sensor according to the present invention will be described below. In addition, the optical interference type pressure sensor according to the present invention is not limited to the following description, and the drawing shows the concept and does not limit the size, scale, position, etc. Detailed descriptions of general matters in the technical field may be omitted.

  An optical interference type pressure sensor according to the present invention includes a movable elastic body that is integrally formed or fixed to a fixed ring and fluctuates in pressure, a mirror mechanism A that is disposed and fixed to the movable elastic body through a fixed base, the fixed ring, and the fixed ring. A fluid introduction device that forms a fluid pressure chamber by fixing or integrating a movable elastic body with a seal, a fixed back plate fixed to the fixing ring on a surface opposite to the fluid introduction device, and disposed on the side of the fixed back plate It is an optical interference type pressure sensor comprising a mirror mechanism B facing the mirror mechanism A in parallel, and a specific pressure (negative pressure) is applied to the mirror chamber surrounded by the movable elastic body, the fixing ring and the fixed back plate. , Atmospheric pressure, positive pressure), or an optical interference type pressure sensor that forms a mirror chamber surrounded by the movable elastic body, the fixed ring, and the fixed back plate and an open path that opens to the outside. And also before An optical interference type pressure sensor in which an optical fiber is fixed to a fixed back plate, and the optical interference type pressure sensor in which the mirror mechanism A is a total reflection type and the mirror mechanism B is a semi-reflection type and faces each other in parallel with a gap. Further, the mirror mechanism B is an optical interference type pressure sensor in which a thin film is formed at the tip of an optical fiber, and an optical interference type pressure sensor in which a mirror protection dam is formed in the mirror chamber.

  The movable elastic bodies 206 and 306 are not particularly limited in material, size, shape, and the like. Any material may be used as long as it has elasticity, and is a single crystal, metal, ceramic, resin, or the like of a metal or oxide or composite oxide having a certain elasticity in repetition of external pressure, preferably a silicon single crystal, Metal and ceramic are preferable, and silicon single crystal or metal is more preferable. Silicon single crystals and metals can be precisely and finely processed by machining, photolithography, and the like. The shape and size may be circular, square, or polygonal, and the size is preferably 1 mm or more. The thickness of the movable elastic body is determined by the working pressure and material of the environment used as the pressure sensor and is not particularly limited. The pressure sensor for weak pressure is extremely thin in micron units, and the pressure sensor for high pressure is thick. The movable elastic body may be integral with the fixing rings 211 and 321, and may be fixed to the gas tightness by an adhesive, seamless welding, EB welding, laser welding, or the like. The movable elastic body integrated with or fixed to the fixing ring is regularly changed by the external pressure (positive pressure / negative pressure of the gas), and the hysteresis is restored with little hysteresis by removing the external pressure. Fixed pedestals 210 and 307 are provided at substantially the center of the movable elastic body, and a mirror mechanism A212 is formed on the upper surface of the fixed pedestal.

  The mirror mechanism A212 is preferably composed of a totally reflecting mirror. For example, by forming a thin film layer of gold, silver, aluminum, nickel, chromium, etc. on the mirror surface of the fixed base, and covering with a nickel + gold thin film to protect it from environmental changes, etc. is there. When a gold thin film is directly formed on a metal, it is preferable to form a nickel thin film on the base. A glass mirror may be fixed.

  The fluid introduction tools 300 and 322 do not particularly limit materials, shapes, dimensions, and the like. The fluid introduction tool is for guiding a positive pressure / negative pressure of gas to the movable elastic bodies 206 and 306, and a fluid pressure chamber 301 is formed by the fluid introduction tool and the movable elastic body. Since the inner diameter of the introduction pipe of the fluid introduction tool is narrow and the fluid pressure chamber has a large volume, it is possible to prevent the movable elastic body from being destroyed due to sudden fluctuations in the fluid pressure (wave pressure). Since positive / negative pressure is applied to the fluid pressure chamber, the fluid introduction tool and the portion to which the movable elastic body is fixed are hermetically sealed and fixed so that there is no gas leakage. The shape is preferably matched to the movable elastic body, and the material is metal, glass, ceramic, resin, or the like, and can be fixed to the movable elastic body in an airtight manner. Alternatively, the fixed elastic base, the movable elastic body, the fixed ring, and the fluid introduction tool are processed into an integrated structure to form a fluid pressure chamber, and the mirror mechanism A is formed on the fixed base, so that the movable elastic body and the fluid are manufactured by the manufacturing method. It can be set as the structure which an introduction tool adheres to airtightness.

  The fixed back plates 310 and 320 are not particularly limited in material, size, shape, and the like. The fixed back plate is fixed to the fixed ring to which the movable elastic body is fixed, and forms a mirror chamber 215 in the space therebetween. The shape and size are preferably similar to those of the movable elastic body, and the material is metal, glass, ceramic, resin, or the like. A mirror mechanism B311 is formed with a gap at the position of the fixed back plate facing the mirror mechanism A. The mirror mechanism B may form a thin mirror on a transparent glass to form a half mirror, or may make a hole in the fixed back plate and fix the half mirror glass in that portion. It is also possible to insert an optical fiber 312 having a half mirror treatment at the tip.

  The mirror chamber may be hermetically sealed with a specific pressure, and a positive / negative pressure relative to the specific pressure may be detected by a movable elastic body. An open path 213 that opens the mirror chamber to the outside may be provided. Alternatively, the positive pressure / negative pressure may be detected by a movable elastic body while the pressure in the mirror chamber is always maintained at atmospheric pressure. By making the specific pressure a vacuum, a pressure sensor for absolute pressure can be obtained. The open path 213 is a path for bringing the mirror chamber 215 and the outside into a gas conduction state, and is formed in the fixed back plate and / or the fixed ring. For example, it is formed in the vicinity of the fixed back plate of the fixed ring, formed on the fixed back plate, and the like.

  An optical fiber 312 made of glass or plastic is fixed to the fixed back plates 310 and 320 at a position corresponding to the mirror mechanism B. The optical fiber may be embedded and fixed in the fixed back plate. Further, the optical fiber 312 having the tip portion mirror-polished and forming the mirror mechanism B with a thin film of chromium, gold, or the like is inserted into the hole of the fixed back plate so as to face the mirror mechanism A and keep the gap between the optical fiber and The fixed back plate may be fixed. Moreover, it may be fixed between a fixed back plate and an optical fiber with a glass tube, a glass capillary, or the like generally used for fiber connection via a lens. As a method for adjusting the gap between the mirror mechanism A and the mirror mechanism B, for example, light having a specific wavelength is sent to the optical fiber 312 that has been subjected to half mirror processing as the mirror mechanism B at the tip of the optical fiber, and the light reflected by the mirror mechanism B Interference light that is transmitted and reflected by the return light reflected by the mirror mechanism A212 is detected by a light receiving element (photodiode, photomultiplier tube, etc.), and the maximum value of the detected electromotive force is detected and measured. While observing the gap with a microscope, the optical fiber is inserted and pulled out to obtain a predetermined gap that is the maximum value of the detected electromotive force without contact between the mirror mechanism B and the mirror mechanism A at the tip. This utilizes the property that the light that interferes with a gap that is an integral multiple of a half wavelength increases the intensity. For the light source, light receiving element, half mirror optical system equipment, arrangement, etc., a normal optical system may be used and detailed description is omitted. The optical interference type pressure sensor according to the present invention does not set the size of the gap between the mirror mechanism A and the mirror mechanism B to any number of microns, but the size of the gap between the mirror mechanism A and the mirror mechanism B is uniform in each product. It is preferable.

  By forming the mirror protection dam 214 on the movable elastic body or / and the fixed back plate on the mirror chamber 215 side, the contact / breakage of the mirror mechanism A and the mirror mechanism B can be prevented.

  A case where a silicon single crystal substrate is used as an example of forming a fixed ring, a movable elastic body, a fixed base, and a mirror mechanism A and forming an optical interference pressure sensor will be described in detail in Example 1. The case where a metal is used as another example will be described in detail in Example 2. The optical interference type pressure sensor according to the present invention is not limited to the structure of the embodiment and the embodiment.

  In the optical interference type pressure sensor according to the present invention, a part of the light guided to an optical fiber is reflected by the mirror mechanism B, which is a half mirror, and returned, and a part of the light is transmitted and reflected by the mirror mechanism A. Then, the light reflected and reflected by the mirror mechanism B (multi-reflected at the gap between the mirror mechanism A and the mirror mechanism B) is transmitted through the mirror mechanism B and interferes with the previous return light, and becomes an interference light. Etc. The movable elastic body is pushed / pulled by the positive pressure / negative pressure of the fluid, and the mirror mechanism A moves together to change the distance between the mirror mechanism A and the mirror mechanism B (which is fixed and does not move). The interference light is changed, and the positive / negative pressure of the fluid can be detected by detecting and analyzing the change of the interference light. For example, by guiding an LED having a wavelength = 525 nm and a half-width = 40 nm to an optical fiber as a light source and projecting the light, a gap of 10 μm at normal pressure changes depending on positive pressure / negative pressure applied to the movable elastic body, and the distance of the gap As a result of the change, the intensity of the light that is multiple-reflected between the mirrors and returns to the multiple reflection optical path 313 as interference light is changed by positive / negative pressure, and the light intensity of the interference light corresponding to the pressure is obtained. As a method of detecting the change in the light intensity of the interference light, it is useful to detect using a light interference detector. Electrostatic drive type interference detectors by the inventors are particularly useful. It is preferable in terms of compatibility with the interference detector that is a detection device that the gap between the mirror mechanism A and the mirror mechanism B of the optical interference pressure sensor described above is uniform in each product. A description of the optical theory of interference by mirrors is omitted.

  In the optical interference type pressure sensor according to the present invention, a fixed base is formed on the movable elastic body, and the mirror mechanism A is formed via the fixed base, so that the mirror is distorted even if the movable elastic body is operated or fluctuated. Since the movable elastic body, which is a diaphragm, is protected by the fluid introduction tool, it is not mechanically contacted and destroyed.

Examples of the optical interference type pressure sensor according to the present invention will be described below. The optical interference type pressure sensor according to the present invention is not limited to the following examples. Moreover, the figure used for description represents a structural concept and does not represent dimensions or scales.

(Example 1) An example of an optical interference type pressure sensor according to the present invention will be described with reference to FIG. 1, FIG. 2, and FIG. In the manufacturing process, as in the semiconductor manufacturing process, manufacturing is performed in a multi-piece arrangement, but here, explanation will be given focusing on one unit. The process will be described using a p-type single crystal silicon wafer (single crystal silicon substrate) having a plane orientation (100). A silicon substrate 200 having a plane orientation (100) shown in FIG. 1A is thermally oxidized (wet oxidation in which a substrate is placed in a quartz tube furnace and heated to introduce water vapor in addition to oxygen gas). A silicon oxide film of about 0.6 μm is formed on the surface, a resist pattern is formed by photolithography (resist application, pre-baking, exposure, development, rinsing, post-baking, etc.), and the remaining resist is used as a mask to oxidize silicon The film is etched with an HF-based etchant, the resist is stripped and removed with a mixed solution of sulfuric acid and hydrogen peroxide, and the remaining silicon oxide film is used as a mask to etch silicon with an etchant TMAH aqueous solution as shown in FIG. Silicon stage A202 was formed.

  A silicon stage B203 as shown in FIG. 5C was formed by a thermal oxidation process, a photolithography method, an etching process, a peeling process, a cleaning process, and the like. The silicon oxide film was entirely removed, a silicon oxide film 204 was formed on the entire surface, and a pattern in which the silicon oxide film 204 was partially removed as shown in FIG.

  Boron was diffused using the silicon oxide film as a mask (e) to form a boron-diffused silicon layer (later to be a movable elastic body) 206 having a thickness of 6 μm as shown in FIG. (The thickness of the boron nucleic acid silicon layer is determined by the pressure to be measured by the pressure sensor.) The resist is peeled off, the oxide film is removed, cleaned, etc., and the oxide film is formed again on the entire surface. (F) The remaining pattern of the oxide film as shown in FIG.

  Using the remaining oxide film as a mask, the silicon crystal is etched by EPW of an anisotropic etching method, and the silicon oxide film is removed by etching. (G) Boron diffusion silicon film 206, fixed base 210, mirror protection dam as shown in FIG. 214, a mirror chamber 215, and a fixing ring 211 are formed. Further, a thin film layer was formed by sputtering chromium, and the mirror mechanism A212 was selectively formed on at least the upper surface of the fixed base 210 by a photolithography method. The mirror mechanism A is a total reflection type mirror and may be a gold thin film layer, and there is no problem even if a thin film layer is formed not only on the upper surface of the fixed base but also on other portions.

  The surface of Pyrex (trademark) glass (fixed back plate) 310 having holes in the open path 213 was polished, cleaned, and metal chromium was selectively vacuum-deposited to form a mirror mechanism B311 as a half mirror. Further, a Pyrex (trademark) glass (fluid introduction channel) 300 having a hole whose central portion is a positive / negative pressure channel was formed. The optical interference type pressure sensor as shown in FIG. 1 was manufactured by anodically bonding the silicon structure in a sandwich state with the fixed back plate 310 and the fluid introduction path 300 of both glasses. [It is a wafer shape in which a large number of units are formed. In order to protect the inner surface from contamination, a film is attached to both sides, cut with a dicing saw, washed after cutting, and the film is peeled off to form individual units. A sensor was used. The optical interference type pressure sensor manufactured in this way is a 1.7 mm square, the inner mirror mechanism is a 0.5 mm square, and the gap between the parallel mirror mechanism A 212 and the mirror mechanism B 311 is about 10 μm. The gap between the mirror protection dam 214 and the fixed back plate 310 is about 6 μm. When an abnormal pressure is applied, the mirror protection dam functions to prevent the mirror mechanism A from contacting the mirror mechanism B by touching the fixed back plate.

  An optical fiber 312 is disposed on the fixed back plate 310 side of the optical interference type pressure sensor thus manufactured (a condensing lens may be inserted between the fixed back plate and the optical fiber). Light up. The projected light is partly reflected by the mirror mechanism B to become reflected light, partly transmitted and reflected by the mirror mechanism A to return light, and the reflected light and return light interfere to form interference light. It can be derived from the optical fiber. The movable elastic body 206 is pushed / pulled and fluctuated by the positive / negative pressure of the fluid applied from the fluid introduction tool 300 to the fluid pressure chamber 301, whereby the mirror mechanism A formed on the fixed base fluctuates in conjunction. Due to this change, the gap between the mirror mechanism A and the mirror mechanism B changes. When the gap changes, the interference light changes and is guided to the optical fiber. That is, the interference light changes according to the pressure fluctuation of the fluid and is guided to the optical fiber.

  Since the optical interference type pressure sensor manufactured in this way has the mirror mechanism A formed on the fixed base 210, the mirror mechanism A is not distorted by fluctuations in the operating elastic body due to pressure fluctuations. Since the mirror protection dam 214 is formed, the movable elastic body 206 and the mirror mechanism are protected from damage from excessive pressure fluctuations. Since the movable elastic body is protected by the fluid introduction tool, it is protected from damage due to mechanical contact.

(Example 2)
An embodiment of an optical interference type pressure sensor according to the present invention will be described with reference to FIG. As shown in FIG. 1A, a disk-shaped SUS material having an outer diameter of φ10 mm and a thickness of 0.5 mm is used. End milled to 0.2 mm. (It is important that the thickness of the SUS of the portion that becomes the movable elastic body is 0.3 mm. In this embodiment, the thickness is 0.3 mm, but of course, it is thicker due to the working pressure as the pressure sensor. It may be thinner or thinner.) Further, both sides are polished. The end milled and polished SUS disk was fitted into a fluid introducing tool 322 made of SUS material, and the surroundings were welded in a gas-tight manner by electron beam welding. The fluid introduction tool forms a fluid pressure chamber 301 therein. Further, the upper surface of the fixed base 307 of the SUS disk was polished to a mirror surface state to obtain a mirror mechanism A212.

  In addition, as shown in FIG. 2C, another shape is formed by integrating the fixing ring 321 and the fluid introduction tool 322 using SUS material. It has a cylindrical shape with an outer diameter of φ10 mm and a length of 16 mm, and a counterbore hole serving as a fluid pressure chamber 301 is processed from one side to φ6 mm and a depth of 15 mm. On the opposite side, it is counterbored so that the thickness of the part that becomes the movable elastic body 306 is 0.3 mm, and the outer diameter is 0.5 mm as the fixed base 307 at the center and 6 mm as the inner diameter of the fixing ring 321. A fixing ring 321 is formed. Polishing was performed until the height of the fixed pedestal on the side of the fixed pedestal became approximately 0.3 mm, and a mirror-polishing finish was performed.

  (A) (c) common outer diameter of φ10mm, thickness of 5mm, φ0.15mm hole in the center, φ2mm, depth of 0.2mm counterbored hole (mirror mechanism A will not hit) Sufficient diameter and depth), a fixed back plate 320 made of SUS material having a hole of φ0.5 mm as an open path was prepared. An optical fiber 312 was prepared, the coating was peeled off, the tip of the fiber was polished, a gold thin film layer was provided at the tip, and the mirror mechanism B was formed. The glass portion of the optical fiber 312 was inserted into the hole of the fixed back plate 320, and the optical fiber was temporarily fixed to the fixed back plate at a position retracted by about 20 μm from the surface of the fixed back plate on the counterbore hole side. Thereafter, the fixed back plate on which the optical fiber was temporarily fixed was bonded and fixed to the fixing ring using an adhesive. The mirror mechanism A and the mirror mechanism B face each other in parallel with a gap of about 20 μm.

  Monochromatic parallel light is projected to the other end of the optical fiber through a half mirror, and interference light reflected by the mirror mechanism A and mirror mechanism B is transmitted through the half mirror, and the light intensity is increased by the photodetector. A measuring system (not shown) for detection is arranged. The measuring system is arranged, and while measuring the light intensity, the optical fiber 312 is gently pushed and pulled out carefully so that the mirror mechanism A and the mirror mechanism B do not come into contact with each other. Stop at the position where the light intensity shows the maximum value. (In this embodiment, the gap between the mirror mechanism A and the mirror mechanism B is adjusted to approximately 10 μm.) The optical fiber 312 and the fixed back plate 320 are bonded and fixed with an adhesive. This gap adjustment method is an application of the fact that interference light is intensified and the light intensity can be detected as a maximum value when the gap is an integral multiple of half the wavelength of monochromatic projection light, and detailed description thereof is omitted.

  The optical interference type pressure sensor thus manufactured is made uniform because the gap is adjusted after assembly. Since the mirror mechanism is formed on the fixed base, the mirror mechanism is not distorted even if the movable elastic body fluctuates due to the pressure of the fluid. Since the open path 213 is always open to atmospheric pressure, interference light can be extracted as a gauge pressure. Further, by sealing the open path with another specific pressure in the mirror chamber, the pressure in the mirror chamber is maintained as a specific pressure, and interference light can be taken out as a pressure based on the specific pressure. .

  The optical interference type pressure sensor manufactured in this way is projected onto an optical fiber from an LED light source having a wavelength of 525 nm and a half-value width of 40 nm. Reflected by mechanism A, transmitted / reflected by mirror mechanism B, and the reflected light is multiple-reflected with mirror mechanism A, transmitted through mirror mechanism B, and interfered with the previous return light to be interfered light from the optical fiber. It can be taken out.

  An optical interference type pressure sensor according to the present invention includes a movable elastic body that is integrally formed or fixed to a fixed ring and fluctuates in pressure, a mirror mechanism A that is disposed and fixed to the movable elastic body through a fixed base, the fixed ring, and the fixed ring. A fluid introduction device that forms a fluid pressure chamber by fixing or integrating a movable elastic body with a seal, a fixed back plate fixed to the fixing ring on a surface opposite to the fluid introduction device, and disposed on the side of the fixed back plate The movable mechanism is composed of a mirror mechanism B facing the mirror mechanism A in parallel. The mirror mechanism A is disposed via a fixed pedestal so that the mirror mechanism A is hardly distorted, and is a diaphragm that is a diaphragm by a fluid introduction tool. Because the body is protected, it is not destroyed by mechanical contact.

It is sectional drawing (a) by one embodiment of the optical interference type pressure sensor which concerns on this invention. (B) is a cross-sectional view taken along line K-K ′ in FIG. (A), and (c) is a cross-sectional view taken along line J-J ′ in FIG. FIG. 2 is a partial cross-sectional perspective view in which an optical fiber is disposed in FIG. 1 according to an embodiment of the optical interference pressure sensor according to the present invention. FIGS. 2A to 2G are process diagrams (a) to (g) of the structure of FIG. 1 according to an embodiment of an optical interference pressure sensor according to the present invention. It is sectional drawing (a) (c) by another embodiment of the optical interference type pressure sensor based on this invention, and a perspective view (b).

Explanation of symbols

200 Silicon substrate 202 Silicon stage A
203 Silicon stage B
204 Silicon oxide film 205 Photoresist 206 306 Movable elastic body 210 307 Fixed base 211 321 Fixed ring 212 Mirror mechanism A
213 Opening path 214 Mirror protection dam 215 Mirror chamber 300 322 Fluid introduction tool 301 Fluid pressure chamber 310 320 Fixed back plate 311 Mirror mechanism B
312 Optical fiber 313 Multiple reflection optical path 314 Fiber fixing material 315 Positive / negative pressure

Claims (7)

In a light interference type pressure sensor in which a movable mirror and a fixed mirror are opposed to each other by pressure fluctuation, a movable elastic body that is integrally formed or fixed to a fixed ring and fluctuates in pressure, and is fixed to the movable elastic body via a fixed base. The fixed mirror plate A, the fixed ring and the movable elastic body fixed or integrated with each other to form a fluid pressure chamber, and the fixed back plate fixed to the fixed ring on the surface opposite to the fluid inlet An optical interference type pressure sensor comprising a mirror mechanism B disposed on the side of the fixed back plate and facing the mirror mechanism A in parallel. The light according to claim 1, wherein the mirror chamber surrounded by the movable elastic body, the fixed ring, and the fixed back plate is hermetically sealed with a specific pressure (negative pressure, atmospheric pressure, positive pressure). Interference type pressure sensor. The optical interference type pressure sensor according to claim 1, wherein an open path that opens to the outside from a mirror chamber surrounded by the movable elastic body, the fixed ring, and the fixed back plate is formed. The optical interference pressure sensor according to claim 1, wherein an optical fiber is fixed to the fixed back plate. 5. The optical interference type pressure sensor according to claim 1, wherein the mirror mechanism A is a total reflection type and the mirror mechanism B is a semi-reflection type and faces each other in parallel with a gap. 6. The optical interference pressure sensor according to claim 5, wherein the mirror mechanism B is formed as a thin film at the tip of an optical fiber. The optical interference type pressure sensor according to claim 1, wherein a mirror protection dam is formed in the mirror chamber.

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