JP5268963B2 - Pressure measuring system and pressure measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure measuring system capable of easily measuring a differential pressure. <P>SOLUTION: The pressure measuring system includes at least one phosphor 2 emitting fluorescence of a first wavelength band and fluorescence of a second wavelength band different from the first wavelength band; a first pressure receiving element 3 receiving a first pressure P<SB>O1</SB>and applying a first modulation to at least the fluorescence of the first wavelength band; a second pressure receiving element 4 receiving a second pressure P<SB>O2</SB>and applying a second modulation to at least the fluorescence of the second wavelength band; an attenuation characteristics measuring section 301 measuring attenuation characteristics of combined light of the fluorescence of the first wavelength band applied with the first modulation and the fluorescence of the second wavelength band applied with the second modulation; and a differential pressure calculating section 302 calculating the differential pressure &Delta;P between the first and second pressures on the basis of the attenuation characteristics. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a measurement technique, and relates to a pressure measurement system and a pressure measurement method.

  When controlling an oil plant or the like, it may be necessary to measure the differential pressure of the fluid at different locations within the oil plant. 2. Description of the Related Art Conventionally, a method has been proposed in which two Fabry-Perot interferometers are arranged at a differential pressure measurement position and a change in optical path difference in each of the two Fabry-Perot interferometers caused by pressure is detected (for example, a patent) References 1 and 2).

JP 2003-166890 A JP 2007-059443 A

  However, in order to read the change in the optical path difference, advanced signal processing may be required to identify the position of the interference fringes. Accordingly, an object of the present invention is to provide a pressure measurement system and a pressure measurement method that can easily measure a differential pressure.

  Aspects of the present invention include: (a) at least one phosphor that emits fluorescence in a first wavelength band and fluorescence in a second wavelength band different from the first wavelength band; and (b) receives a first pressure. A first pressure-receiving element that applies a first modulation to the fluorescence in at least the first wavelength band; and (c) a second pressure that receives the second pressure and applies the second modulation to the fluorescence in at least the second wavelength band. And (d) an attenuation characteristic for measuring the attenuation characteristics of the combined light of the fluorescence in the first wavelength band given the first modulation and the fluorescence in the second wavelength band given the second modulation. The gist of the present invention is a pressure measurement system including a measurement unit and (e) a differential pressure calculation unit that calculates a differential pressure between the first and second pressures based on a damping characteristic.

  Another aspect of the present invention includes (a) emitting fluorescence in a first wavelength band and fluorescence in a second wavelength band different from the first wavelength band, and (b) fluorescence in at least the first wavelength band. Providing a first modulation depending on the first pressure, (c) applying a second modulation depending on the second pressure to at least the second wavelength band of fluorescence, (d) Measuring the attenuation characteristics of the combined light of the fluorescence in the first wavelength band given the first modulation and the fluorescence in the second wavelength band given the second modulation; and (e) based on the attenuation characteristics Thus, the gist of the present invention is to calculate a differential pressure between the first and second pressures.

  Still another aspect of the present invention includes: (a) a light emitting element that emits light; (b) a first pressure receiving element that receives a first pressure and applies a first modulation to the light; and (c) a second A second pressure-receiving element that receives pressure and applies second modulation to the light; and (d) a first phosphor that emits fluorescence of at least the first wavelength band when irradiated with the light that has been given the first modulation. And (e) a second phosphor that is irradiated with light having a second modulation and emits fluorescence in at least a second wavelength band different from the first wavelength band, and (f) a first wavelength. An attenuation characteristic measurement unit that measures the attenuation characteristics of the combined light of the fluorescence in the band and the fluorescence in the second wavelength band; and (g) a differential pressure that calculates the differential pressure between the first and second pressures based on the attenuation characteristic. A gist of the invention is a pressure measurement system including a calculation unit.

  Still another aspect of the present invention provides: (a) emitting light; (b) providing light with a first modulation that depends on a first pressure; and (c) applying a second pressure to the light. A second modulation that depends on: (d) excitation of fluorescence of at least a first wavelength band by light provided with the first modulation; and (e) a second modulation. Excitation of at least a second wavelength band fluorescence different from the first wavelength band by the reflected light; and (f) attenuation characteristics of the combined light of the first wavelength band fluorescence and the second wavelength band fluorescence. And (g) calculating a differential pressure between the first and second pressures based on the damping characteristic.

  According to the present invention, it is possible to provide a pressure measuring system and a pressure measuring method capable of easily measuring a differential pressure.

1 is a schematic diagram of a pressure measurement system according to a first embodiment of the present invention. It is a one part expansion schematic diagram of the pressure measurement system which concerns on the 1st Embodiment of this invention. It is a top view of the 1st pressure receiving element concerning a 1st embodiment of the present invention. It is the 1st sectional view seen from the IV-IV direction of the 1st pressure sensing element concerning a 1st embodiment of the present invention. It is the 2nd sectional view seen from the IV-IV direction of the 1st pressure sensing element concerning a 1st embodiment of the present invention. It is the 3rd sectional view seen from the IV-IV direction of the 1st pressure sensing element concerning a 1st embodiment of the present invention. It is a 1st graph regarding the pressure-sensitive film which concerns on the 1st Embodiment of this invention. It is a 2nd graph regarding the pressure-sensitive film which concerns on the 1st Embodiment of this invention. It is a 1st graph of the spectrum of the fluorescence which concerns on the 1st Embodiment of this invention. It is a 2nd graph of the spectrum of the fluorescence which concerns on the 1st Embodiment of this invention. It is a 3rd graph of the spectrum of the fluorescence which concerns on the 1st Embodiment of this invention. It is a graph which shows the example of the time change of the fluorescence intensity which concerns on the 1st Embodiment of this invention. It is a flowchart of the pressure measuring method which concerns on the 1st Embodiment of this invention. It is a graph which shows the relationship between the fluorescence lifetime which concerns on the 1st modification of the 1st Embodiment of this invention, and a light quantity ratio. It is a schematic diagram of the pressure measurement system which concerns on the 2nd modification of the 1st Embodiment of this invention. It is a schematic diagram of the 1st pressure receiving element which concerns on the 2nd modification of the 1st Embodiment of this invention. It is a schematic diagram of the pressure measurement system which concerns on the 2nd Embodiment of this invention. It is a graph of the spectrum of excitation light and fluorescence according to the second embodiment of the present invention. It is a graph which shows the relationship between the excitation light given the modulation | alteration which concerns on the 2nd Embodiment of this invention, and a pressure. It is a schematic diagram of the pressure measurement system which concerns on the 3rd Embodiment of this invention. It is a graph which shows the example of the attenuation characteristic depending on the atmospheric temperature of the fluorescence intensity of the fluorescent substance concerning the 4th Embodiment of this invention. It is a schematic diagram of the pressure measurement system which concerns on the 4th Embodiment of this invention. It is a schematic diagram of the pressure measurement system which concerns on the 5th Embodiment of this invention. It is a flowchart of the pressure measuring method which concerns on the 5th Embodiment of this invention. It is a schematic diagram of the pressure measurement system which concerns on the 6th Embodiment of this invention. It is a flowchart of the pressure measuring method which concerns on the 6th Embodiment of this invention. It is a 1st schematic diagram of the pressure measurement system which concerns on the 7th Embodiment of this invention. It is a 2nd schematic diagram of the pressure measurement system which concerns on the 7th Embodiment of this invention. It is a schematic diagram of the pressure measurement system which concerns on the 8th Embodiment of this invention. It is a schematic diagram of the pressure measurement system which concerns on the 9th Embodiment of this invention. It is a graph which shows the example of the time change of the fluorescence intensity which concerns on other embodiment of this invention.

  Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions and the like should be determined in light of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(First embodiment)
As shown in FIG. 1, the optical pressure measurement system according to the first embodiment receives a fluorescent substance 2 that emits fluorescence and a first pressure P _O1 and applies a first modulation to the fluorescence. The pressure receiving element 3, the second pressure receiving element 4 that receives the second pressure P _O2 and applies the second modulation to the fluorescence, and the first that transmits the first wavelength band of the fluorescence given the first modulation. The second wavelength filter 6 that transmits the second wavelength band different from the first wavelength band of the fluorescence given the second modulation, and the first and second wavelength filters. An attenuation characteristic measurement unit 301 that measures the attenuation characteristic of the combined fluorescent light, a differential pressure calculation unit 302 that calculates a differential pressure ΔP between the first and second pressures P _O1 and P _O2 based on the attenuation characteristic, Is provided. Note that the first wavelength band and the second wavelength band are mutually different wavelength bands, but may be partially overlapped.

  The pressure measurement system further includes a light emitting element 1 that irradiates the phosphor 2 with excitation light. For the light emitting element 1, a semiconductor light emitting element such as a light emitting diode (LED) and a semiconductor laser (LD) can be used. More specifically, the light-emitting element 1 can be a four-element light-emitting element using AlGaInP as a chip material and a three-element light-emitting element using InGaN as a chip material. For example, an energization control unit 90 is connected to the light emitting element 1. The energization control unit 90 controls energization (ON / OFF) so as to blink the light emitting element 1, and intermittently emits excitation light of the phosphor 2 from the light emitting element 1.

The phosphor 2 is made of a fluorescent material or a fluorescent material doped with a transition metal. As the fluorescent material doped with the transition metal, Cr ³⁺ material such as ruby, Mn ²⁺ material, Mn ⁴⁺ material, and Fe ²⁺ material can be used. Alternatively, the phosphor 2 is composed of strontium aluminate (SrAl ₂ O ₄ series) doped with europium (Eu), Alexandrite (variant of BeAl ₂ O ₄ ), chromium-doped yttrium aluminum garnet (Cr ^4+). : YAG), titanium-doped sapphire (Ti: Sapphire), chromium-doped lithium fluoride / strontium / aluminum (Cr: LiSAF), or ytterbium-doped yttrium / aluminum (Yb: YAG). It is not limited. The phosphor 2 may be stored in a holding member or the like.

  Fluorescence including the first wavelength band and the second wavelength band emitted from the phosphor 2 is propagated to the first pressure receiving element 3 and the second pressure receiving element 4 via the optical waveguide 11 and the optical waveguide 21, respectively. The As shown in FIG. 2, the fluorescence emitted from the phosphor 2 is collected between the phosphor 2 and the ends of the optical waveguide 11 and the optical waveguide 21 at the ends of the optical waveguide 11 and the optical waveguide 21. A lens 31 that emits light may be disposed. As materials for the optical waveguides 11 and 21, plastics such as polymethyl methacrylate resin (PMMA: Poly (methymethacrylate)), quartz, and multicomponent glass can be used. The optical waveguides 11 and 21 may include an optical fiber including a core and a cladding, and a protective tube that covers the optical fiber. However, the optical waveguides 11 and 21 are not limited to these as long as light can propagate.

The fluorescence that has been subjected to the first modulation by the first pressure receiving element 3 shown in FIG. 1 is propagated to the first wavelength filter 5 by the optical waveguide 12. Further, the fluorescence that has been subjected to the second modulation by the second pressure receiving element 4 is propagated to the second wavelength filter 6 by the optical waveguide 22. Here, the first pressure receiving element 3 includes the optical waveguide 11 and the holder 60 into which the optical waveguide 12 is inserted, as shown in FIG. 3 and FIG. 4 which is a cross-sectional view from the IV-IV direction. The first pressure-receiving element 3 is further disposed on the pressure-sensitive film 50 that receives the first external pressure P _O1 , and on the surface of the pressure-sensitive film 50 that faces the ends of the optical waveguides 11 and 12. A reflection film 27 that reflects the fluorescence emitted from the end of the optical waveguide 11 and a housing 43 that defines the distance between the ends of the optical waveguides 11 and 12 and the reflection film 27. As the material of the reflective film 27, for example, gold (Au) or the like can be used.

The holder 60 is provided with a pressure-sensitive film 50, a housing 43, and a vent hole 160 for adjusting the internal pressure P _{I1 in} a region surrounded by the holder 60. The opening and closing of the vent hole 160 is controlled by the release valve 70. Further, a base portion 40 that defines the radius a shown in FIG. 3 of the pressure sensitive film 50 to be exposed is disposed outside the pressure sensitive film 50. The fluorescence emitted from the end of the optical waveguide 11 shown in FIG. 4 is reflected by the surface of the reflective film 27 and enters the optical waveguide 12.

Here, the pressure-sensitive film 50 of the first pressure receiving element 3 does not bend in the “steady state” in which the internal pressure P _I1 is equal to the first pressure P _O1 from the outside. However, as shown in FIG. 5, when the first external pressure P _O1 becomes larger than the internal pressure P _I1 , the pressure-sensitive film 50 bends inward. Since the pressure sensitive film 50 is disposed on the back surface of the reflective film 27, the reflective film 27 is also bent along with the pressure sensitive film 50. At this time, the distance between the end portions of the optical waveguides 11 and 12 and the reflective film 27 is narrower than in the steady state. Therefore, the light intensity of the fluorescence reflected by the surface of the reflective film 27 and entering the optical waveguide 12 becomes stronger than in the steady state.

Further, as shown in FIG. 6, when the first external pressure P _O1 becomes smaller than the internal pressure P _I1 , the pressure sensitive film 50 bends outward. At this time, the distance between the end portions of the optical waveguides 11 and 12 and the reflective film 27 is wider than in the steady state. Therefore, the light intensity of the fluorescence reflected by the surface of the reflection film 27 and entering the optical waveguide 12 becomes weaker than that in the steady state. Thus, the first pressure receiving element 3 has the fluorescence light intensity including the first wavelength band and the second wavelength band propagating from the optical waveguide 11 to the optical waveguide 12 in accordance with the first pressure P _O1. Modulate.

As shown in FIG. 5, the deflection w _{1 of the} pressure-sensitive film 50 when the first pressure P _O1 is applied from the outside is as follows when the pressure-sensitive film 50 has a radius a as shown in FIG. It is expressed by an expression.
w ₁ = (P _O1 -P _I1 ) × (a ² -r ² ) ² / (64 × Z) (1)
Here, r (r: 0 ≦ r ≦ a) is a distance from the center position M of the pressure sensitive film 50 to the measurement position. Z is given by the following equation (2).
Z = Y × t ³ / [12 × (1-υ ² )] (2)
In the equation (2), Y is the Young's modulus of the pressure-sensitive film 50, t is the thickness of the pressure-sensitive film 50, and υ is the Poisson's ratio of the pressure-sensitive film 50.

FIG. 7 is a graph plotting the relationship between the first external pressure P _O1 and the deflection w ₁ when the thickness t of the pressure-sensitive film 50 shown in FIGS. 4 to 6 is 50 μm. In FIG. 7, plots are made for the cases where the radius a of the pressure-sensitive film 50 illustrated in FIG. 3 is 0.01 mm, 0.10 mm, and 1.00 mm. FIG. 8 is a graph plotting the relationship between the first external pressure P _O1 and the deflection w ₁ when the thickness t of the pressure-sensitive film 50 is 1 μm. In FIG. 8, plots are made for each of cases where the radius a of the pressure-sensitive film 50 is 0.01 mm, 0.10 mm, and 1.00 mm. As shown in FIGS. 7 and 8, the pressure sensitivity of the first pressure-receiving element 3 with respect to the first pressure P _O1 from the outside is adjusted by appropriately selecting the radius a and the thickness t of the pressure-sensitive film 50. It is possible.

The second pressure receiving element 4 shown in FIG. 1 has the fluorescence light intensity including the first wavelength band and the second wavelength band propagating from the optical waveguide 21 to the optical waveguide 22 according to the second pressure P _O2. Modulate. The constituent elements of the second pressure receiving element 4 are the same as those of the first pressure receiving element 3 shown in FIGS.

When the phosphor 2 shown in FIG. 1 is made of ruby or the like, the first wavelength filter 5 transmits the fluorescence given the first modulation in the first wavelength band of less than 700 nm, for example, as shown in FIG. Then, the fluorescence given the first modulation in the second wavelength band is shielded. In addition, the second wavelength filter 6 transmits the fluorescence given the second modulation in the second wavelength band of 700 nm or more, and shields the fluorescence given the second modulation in the first wavelength band. . For example, the center wavelength is different between the first wavelength band and the second wavelength band. Here, the “centroid wavelength” refers to a wavelength that becomes the center of gravity in the spectral region. Alternatively, the first wavelength band and the second wavelength band may be set so that the respective integrated light amounts are equal. In this case, the first wavelength band and the second wavelength band may have different bandwidths. The center-of-gravity wavelengths may be different from each other or the same. FIG. 9 shows a case where there is no differential pressure ΔP between the first pressure P _O1 and the second pressure P _O2 as shown in the following equation (3).
P _O1 = P _O2 (3)

Here, as shown in the following equation (4), when the second pressure P _O2 increases with respect to the first pressure P _O1 , the first pressure receiving element 3 is compared with the case where there is no differential pressure ΔP. The ratio of the amount of fluorescent light propagating from the second pressure-receiving element 4 to the optical waveguide 22 with respect to the amount of fluorescent light propagating in the optical waveguide 12 is increased. Therefore, as shown in FIG. 10, the light amount ratio of the light amount of the fluorescence transmitted through the second wavelength filter 6 to the light amount of the fluorescence transmitted through the first wavelength filter 5 is larger than the case where there is no differential pressure ΔP. Become.
P _O1 <P _O2 (4)

Further, as shown in the following formula (5), when the second pressure P _O2 becomes smaller than the first pressure P _O1 , light is transmitted from the first pressure receiving element 3 as compared with the case where there is no differential pressure ΔP. The ratio of the amount of fluorescent light propagating from the second pressure-receiving element 4 to the optical waveguide 22 with respect to the amount of fluorescent light propagating in the waveguide 12 is reduced. Therefore, as shown in FIG. 11, the light amount ratio of the light amount of the fluorescence transmitted through the second wavelength filter 6 to the light amount of the fluorescence transmitted through the first wavelength filter 5 is small as compared with the case where there is no differential pressure ΔP. Become.
P _O1 > P _O2 ... (5)
9 to 11 show an example in which the first wavelength band and the second wavelength band are separated at a wavelength of 700 nm, the wavelength that is the boundary between the first wavelength band and the second wavelength band is this. It is not limited to. For example, when the fluorescent substance constituting the phosphor 2 is other than ruby, a wavelength that becomes a boundary between the first wavelength band and the second wavelength band may be set according to the fluorescence spectrum.

  The fluorescence transmitted through the first wavelength filter 5 shown in FIG. 1 and the fluorescence transmitted through the second wavelength filter 6 are superimposed and received by the light receiving element 7 as coupled light. As the light receiving element 7, a photodiode or the like can be used. A processing unit 8 that amplifies the output signal of the light receiving element 7 is connected to the light receiving element 7. A central processing unit (CPU) 300 is connected to the processing unit 8. The attenuation characteristic measurement unit 301 is included in the CPU 300. The attenuation characteristic measuring unit 301 observes a temporal change in the fluorescence intensity of the fluorescence measured by the light receiving element 7 from the moment when the light emitting element 1 is extinguished or immediately after, and acquires a measured value of the fluorescence attenuation characteristic such as the fluorescence lifetime τ. . As shown in FIG. 12, the time required for the fluorescence intensity to drop to 1 / e as compared to the moment when the light emitting element 1 is extinguished or immediately after is turned off is defined as the fluorescence lifetime τ. Note that e is a natural logarithm.

Here, the fluorescence lifetime τ tends to be longer as the wavelength is shorter and shorter as the wavelength is longer. Therefore, when the ratio of the amount of fluorescent light transmitted through the second wavelength filter 6 to the amount of fluorescent light transmitted through the first wavelength filter 5 shown in FIG. 1 increases, the fluorescence lifetime τ of the combined light received by the light receiving element 7. Tend to be shorter. Therefore, when the fluorescence lifetime τ of the combined light received by the light receiving element 7 is shortened, the second pressure P _O2 is relatively relative to the first pressure P _{O1 as} compared to the case where there is no differential pressure ΔP. It is getting bigger.

Further, when the ratio of the amount of fluorescent light transmitted through the second wavelength filter 6 to the amount of fluorescent light transmitted through the first wavelength filter 5 decreases, the fluorescence lifetime τ of the combined light received by the light receiving element 7 tends to increase. It is in. Accordingly, when the fluorescence lifetime τ of the coupled light received by the light receiving element 7 is increased, the second pressure P _O2 is relatively set with respect to the first pressure P _{O1 as} compared with the case where there is no differential pressure ΔP. It is getting smaller.

As described above, the fluorescence decay characteristics such as the fluorescence lifetime τ and the differential pressure ΔP between the first and second pressures P _O1 and P _O2 have a correlation. The differential pressure calculation unit 302 calculates the first and second pressures P _O1 and P _O2 based on the correlation acquired in advance between the fluorescence attenuation characteristic and the differential pressure ΔP and the measured value of the fluorescence attenuation characteristic. A measured value of the differential pressure ΔP is calculated. A data storage device 400 including a relationship storage unit 401 is connected to the CPU 300. The relationship storage unit 401 obtains in advance the fluorescence attenuation characteristics such as the fluorescence lifetime τ and the differential pressure ΔP between the first and second pressures P _O1 and P _O2 , which are used by the differential pressure calculation unit 302. Save the correlation. The correlation may be expressed as a function or may be expressed in a table format.

An input device 321, an output device 322, a program storage device 323, and a temporary storage device 324 are further connected to the CPU 300. As the input device 321, a switch, a keyboard, and the like can be used. As the output device 322, an optical indicator, a digital indicator, a liquid crystal display device, or the like can be used. The output device 322 outputs the measured value of the differential pressure ΔP between the first pressure P _O1 calculated by the differential pressure calculation unit 302 and the second pressure P _O2 . The program storage device 323 stores a program for causing the CPU 300 to execute data transmission / reception between devices connected to the CPU 300. The temporary storage device 324 temporarily stores data in the calculation process of the CPU 300.

Next, the pressure measurement method according to the first embodiment will be described using the flowchart shown in FIG.
(A) In step S101, the light emitting element 1 is energized from the energization control unit 90 shown in FIG. 1, and the phosphor 2 is irradiated with excitation light from the light emitting element 1. The phosphor 2 irradiated with the excitation light emits fluorescence. In step S <b> 211, a part of the fluorescence emitted from the phosphor 2 is propagated to the first pressure receiving element 3 through the optical waveguide 11. In step S <b> 221, a part of the fluorescence emitted from the phosphor 2 is propagated to the second pressure receiving element 4 through the optical waveguide 21.

(B) In step S212, the first pressure receiving element 3 applies the first modulation to the light intensity of the fluorescence according to the first pressure P _O1 . In step S222, the second pressure receiving element 4 applies the second modulation to the light intensity of the fluorescence according to the second pressure _PO2 . Thereafter, in step S 213, the fluorescence given the first modulation is propagated to the first wavelength filter 5 through the optical waveguide 12 and passes through the first wavelength filter 5. In step S223, the fluorescence that has been subjected to the second modulation is propagated to the second wavelength filter 6 through the optical waveguide 22 and passes through the second wavelength filter 6.

  (C) In step S301, the first wavelength band fluorescence transmitted through the first wavelength filter 5 and the second wavelength band fluorescence transmitted through the second wavelength filter 6 are combined, and the combined light is Light is received by the light receiving element 7. The fluorescence intensity of the combined light received by the light receiving element 7 is transmitted to the attenuation characteristic measuring unit 301 of the CPU 300 through the processing unit 8. In step S302, the energization from the energization control unit 90 to the light emitting element 1 is cut off, and the light emitting element 1 is turned off. The attenuation characteristic measurement unit 301 observes a temporal change in the fluorescence intensity of the combined light from the moment when the light emitting element 1 is turned off or immediately after, and acquires a measurement value of the attenuation characteristic such as the fluorescence lifetime τ of the combined light. The attenuation characteristic measurement unit 301 transmits the acquired measurement value of the attenuation characteristic to the differential pressure calculation unit 302.

(D) In step S303, the differential pressure calculation unit 302 obtains, in advance, the correlation obtained from the relationship storage unit 401 between the fluorescence attenuation characteristics and the differential pressures ΔP of the first and second pressures P _O1 and P _O2. Read relationship. Further, the differential pressure calculation unit 302 calculates a measured value of the differential pressure ΔP between the first pressure P _O1 and the second pressure P _O2 based on the read correlation and the measured value of the attenuation characteristic. To do. Thereafter, the differential pressure calculation unit 302 displays the calculated measurement value of the differential pressure ΔP on the output device 322, and ends the pressure measurement method according to the first embodiment.

According to the pressure measurement system and the pressure measurement method according to the first embodiment described above, the first pressure P _O1 , the second pressure P _O2, and the like based on the fluorescence decay characteristics such as the fluorescence lifetime τ. The differential pressure ΔP can be calculated easily and accurately.

(First modification of the first embodiment)
FIG. 14 shows the attenuation characteristics of fluorescence received by the light receiving element 7 and the ratio of the amount of fluorescent light transmitted through the second wavelength filter 6 to the amount of fluorescent light transmitted through the first wavelength filter 5 as shown in FIG. Have a correlation. In the first embodiment, the differential pressure calculation unit 302 uses the first and second values based on the previously acquired correlation between the fluorescence attenuation characteristic and the differential pressure ΔP and the measured value of the fluorescence attenuation characteristic. An example is shown in which the measured value of the differential pressure ΔP between the pressures P _O1 and P _O2 is calculated. On the other hand, the differential pressure calculation unit 302 transmits the fluorescence transmitted through the first wavelength filter 5 based on the correlation acquired in advance between the fluorescence attenuation characteristic and the light amount ratio and the measured value of the fluorescence attenuation characteristic. A measured value of the light amount ratio of the light amount of the fluorescence transmitted through the second wavelength filter 6 to the light amount of may be calculated.

In this case, since the light quantity ratio and the differential pressure ΔP have a correlation, the differential pressure calculation unit 302 is based on the correlation acquired in advance between the light quantity ratio and the differential pressure ΔP and the measured value of the light quantity ratio. Thus, a measured value of the differential pressure ΔP between the first and second pressures P _O1 and P _O2 is calculated. In FIG. 14, the attenuation characteristic of the fluorescence received by the light receiving element 7, the ratio of the amount of fluorescence transmitted through the second wavelength filter 6 to the amount of fluorescence transmitted through the first wavelength filter 5, and The correlation was shown. On the other hand, the attenuation characteristic of the fluorescence received by the light receiving element 7 is also correlated with the light quantity ratio of the fluorescence light quantity transmitted through the first wavelength filter 5 to the fluorescence light quantity transmitted through the second wavelength filter 6. Have Therefore, in the present disclosure, the “light quantity ratio” means the ratio of the quantity of fluorescent light transmitted through the second wavelength filter 6 to the quantity of fluorescent light transmitted through the first wavelength filter 5 and the second wavelength filter 6. The ratio may be any of the ratio of the amount of fluorescent light transmitted through the first wavelength filter 5 to the amount of transmitted fluorescent light.

(Second modification of the first embodiment)
In FIG. 1, a light reflection type first pressure receiving element 3 and a second pressure receiving element 4 are shown. On the other hand, as shown in FIG. 15, a light transmission type first pressure receiving element 83 and a second pressure receiving element 84 may be used. For example, as shown in FIG. 16, the light transmission type first pressure receiving element 83 includes a diffractive element 127 inserted between the optical waveguide 11 and the optical waveguide 12, a housing 143 for holding the diffractive element 127, and an external device. And a pressure-sensitive film 150 that receives the first pressure P _O1 .

The diffraction element 127 is a fiber Bragg grating having a periodic structure in which first and second refractive index portions having different refractive indexes are alternately arranged. Only a specific wavelength component of the fluorescence incident on the diffraction element 127 is selectively attenuated by the periodic structure of the first refractive index portion and the second refractive index portion. Here, when the average refractive index in the periodic structure of the first refractive index part and the second refractive index part is n _D and the interval of the periodic structure is Λ _m1 , the Bragg wavelength λ _B represented by the following equation (6) is obtained. The attenuated fluorescence propagates to the optical waveguide 12.
λ _B = 2 × n _D × Λ _m1 (6)

Here, when the first pressure P _O1 is applied to the pressure-sensitive film 150 from the outside, the diffraction element 127 is also bent, so that the interval Λ _{m1 of the} periodic structure is increased. Therefore, the Bragg wavelength λ _B is also shifted to the long wavelength side. As described above, in the light transmission type first pressure receiving element 83, the spectral spectrum of the fluorescence propagating to the optical waveguide 12 is modulated according to the first pressure P _O1 . The components of the light transmissive second pressure receiving element 84 shown in FIG. 15 are the same as the components of the light transmissive first pressure receiving element 83 shown in FIG. The light transmission type second pressure receiving element 84 modulates the spectral spectrum of the fluorescence propagating to the optical waveguide 22 in accordance with the second pressure P _O2 .

(Second Embodiment)
In the pressure measurement system according to the second embodiment, for example, a fluorescent material having a conversion efficiency of less than 100% is used as the material of the phosphor 2 shown in FIG. Therefore, part of the excitation light emitted from the light emitting element 1 is also propagated to the first pressure receiving element 3 through the optical waveguide 11. In the first pressure receiving element 3, the excitation light is also given the first modulation in the same manner as fluorescence. The fluorescence given the first modulation is propagated to the first wavelength filter 15 through the optical waveguide 12. In the second embodiment, the first wavelength filter 15 transmits the excitation light together with the wavelength component of less than 700 nm of fluorescence, as shown in FIG.

As shown in FIG. 12, immediately after or immediately after the light emitting element 1 starts irradiating the excitation light, the phosphor 2 shown in FIG. 17 does not emit fluorescence yet. The light intensity measurement unit 303 included in the CPU 300 displays the measured value of the light intensity of the excitation light given the first modulation measured by the light receiving element 7 immediately or immediately after the light emitting element 1 starts the irradiation of the excitation light. get. Here, as shown in FIG. 19, the light intensity of the excitation light subjected to the first modulation has a correlation with the first pressure P _O1 .

The pressure calculation unit 304 illustrated in FIG. 17 includes the correlation between the light intensity of the excitation light given the first modulation and the first pressure P _O1 acquired in advance, and the excitation light given the first modulation. Based on the measured value of the light intensity, the measured value of the first pressure P _O1 is calculated. Furthermore, the pressure calculation unit 304 calculates the measurement value of the second pressure P _O2 based on the calculated measurement value of the first pressure P _{O1 and} the measurement value of the differential pressure ΔP calculated by the differential pressure calculation unit 302. calculate.

In the second embodiment, the relationship storage unit 401 uses the light intensity of the excitation light subjected to the first modulation as shown in FIG. 19 and the first pressure P _O1 used by the pressure calculation unit 304. And the previously obtained correlation is stored. The correlation may be expressed as a function or may be expressed in a table format. Since the other components of the pressure measurement system shown in FIG. 17 according to the second embodiment are the same as those of the first embodiment, description thereof will be omitted. According to the pressure measurement system according to the second embodiment, it is possible to obtain respective measured values of the first pressure P _O1 , the second pressure P _O2 , and the differential pressure ΔP.

(Third embodiment)
As shown in FIG. 20, the pressure measurement system according to the third embodiment corrects fluctuations in the light intensity of the detected excitation light and the light emission detector 91 that detects the excitation light emitted by the light emitting element 1. And a light emission intensity correction unit 92 which is a device. A photodiode or the like can be used for the light emission detector 91. The light emission detector 91 transmits the light intensity measurement value Im of the detected excitation light to the light emission intensity correction unit 92. The light emission intensity correction unit 92 calculates the light intensity variation ΔI by taking the difference between the predetermined value Ic of the light intensity of the excitation light and the measured value Im. Further, the light emission intensity correction unit 92 causes the energization control unit 90 to control the energization amount to the light emitting element 1 so that the fluctuation amount ΔI of the light intensity of the excitation light becomes zero.

The fluctuation of the light intensity of the excitation light emitted from the light emitting element 1 is caused by the measured values of the first pressure P _O1 , the second pressure P _O2 , and the differential pressure ΔP calculated by the pressure calculation unit 304 and the differential pressure calculation unit 302. May have an impact. On the other hand, the pressure measurement system according to the third embodiment suppresses the fluctuation amount ΔI of the light intensity of the excitation light by feedback control, so that the first pressure P _O1 , the second pressure P _O2 , and It becomes possible to accurately measure the differential pressure ΔP.

(Fourth embodiment)
FIG. 21 shows an example of the fluorescence intensity of the phosphor 2 after excitation light quenching when the ambient temperature T of the phosphor 2 is changed. The ambient temperature T of the phosphor 2 is, for example, the temperature of the gas in contact with the phosphor 2 or a heat conductive holding member that stores the phosphor 2. Here, under the first temperature condition, the ambient temperature T of the phosphor 2 is the lowest, and under the second to fifth temperature conditions, the ambient temperature T of the phosphor 2 is sequentially increased. As shown in FIG. 21, the fluorescence lifetime τ of the phosphor 2 tends to become shorter as the ambient temperature T of the phosphor 2 increases.

  Therefore, when the atmospheric temperature T of the phosphor 2 shown in FIGS. 1, 17, and 20 varies, it may be difficult to accurately measure the differential pressure ΔP. On the other hand, the pressure measurement system according to the fourth embodiment includes a temperature controller 101 that keeps the ambient temperature T of the phosphor 2 constant as shown in FIG. The other components of the pressure measurement system according to the fourth embodiment are the same as those of the pressure measurement system according to the third embodiment shown in FIG.

  In the pressure measurement system according to the fourth embodiment shown in FIG. 22, since the temperature controller 101 keeps the ambient temperature T of the phosphor 2 constant, the variation in the fluorescence attenuation characteristic based on the variation in the ambient temperature T is suppressed. Is done. Therefore, the pressure measurement system according to the fourth embodiment makes it possible to obtain a measured value of the differential pressure ΔP more accurately.

(Fifth embodiment)
As shown in FIG. 23, the pressure measurement system according to the fifth embodiment includes a thermometer 102 that measures a measured value Tm of the ambient temperature T of the phosphor 2, and first and second pressure receiving elements 3 and 4. And an attenuation characteristic correction unit 305 that corrects fluctuations due to fluctuations in the atmospheric temperature T of the attenuation characteristics such as the fluorescence lifetime τ of the fluorescence before being modulated by. For the thermometer 102, for example, a thermistor, a platinum temperature sensor, or the like can be used.

Here, the ambient temperature T of the phosphor 2 when the correlation between the fluorescence lifetime τ stored in the relationship storage unit 401 and the differential pressure ΔP between the first and second pressures P _O1 and P _O2 is acquired. Is a reference temperature Ts. The pressure measurement system according to the fifth embodiment includes a variation amount ΔT of the ambient temperature from the reference temperature Ts and a variation amount of the fluorescence lifetime of the fluorescence before being modulated by the first and second pressure receiving elements 3 and 4. A correction information storage unit 402 is further provided for storing a previously acquired relationship between Δτ and Δτ.

As shown in the following equation (7), the relationship between the variation amount ΔT of the ambient temperature and the variation amount Δτ of the fluorescence lifetime has the variation amount ΔT of the ambient temperature as an independent variable and the variation amount Δτ of the fluorescence lifetime as a dependent variable. It may be expressed by a function.
Δτ = f (ΔT) (7)
The attenuation characteristic correction unit 305 calculates a value ΔTc of the variation amount of the ambient temperature by taking the difference between the measured value Tm of the ambient temperature of the phosphor 2 and the reference temperature Ts according to the following equation (8).
ΔTc = Tm-Ts (8)

In addition, the attenuation characteristic correction unit 305 substitutes the calculated value ΔTc of the variation amount of the ambient temperature into the variable ΔT of the variation amount of the ambient temperature in the equation (7), and calculates the variation amount Δτc ₁ of the fluorescence lifetime. Further, the attenuation characteristic correction unit 305 takes the difference between the measured value τm of the fluorescence lifetime acquired by the attenuation characteristic measurement unit 301 and the calculated value Δτc ₁ of the fluctuation amount of the fluorescence lifetime according to the following equation (9), and calculates the fluorescence lifetime. The correction value τc ₁ is calculated. Thereby, the fluorescence lifetime τm at the measured ambient temperature Tm is converted into the fluorescence lifetime τc ₁ at the reference temperature Ts.
τc ₁ = τm-Δτc ₁ ... (9)

In the fifth embodiment, the differential pressure calculation unit 302 correlates the fluorescence lifetime correction value τc calculated by the attenuation characteristic correction unit 305 with the fluorescence lifetime τ and the differential pressure ΔP stored in the relationship storage unit 401. Then, the measured value of the differential pressure ΔP between the first and second pressures P _O1 and P _O2 is calculated.

Next, a pressure measuring method according to the fifth embodiment will be described using the flowchart shown in FIG.
(A) First, steps S101 to S301 are performed in the same manner as the pressure measurement method according to the first embodiment shown in FIG. Next, in step S302 of FIG. 24, the attenuation characteristic measurement unit 301 shown in FIG. 23 observes the temporal change in the fluorescence intensity of the combined light from the moment when the light emitting element 1 is turned off or immediately after that, and the fluorescence lifetime of the combined light is measured. Obtain the measured value τm. The attenuation characteristic measurement unit 301 transmits the acquired measurement value τm of the attenuation characteristic to the attenuation characteristic correction unit 305.

  (B) In step S401, the thermometer 102 measures the measured value Tm of the ambient temperature of the phosphor 2. Furthermore, the thermometer 102 transmits the measured value Tm of the ambient temperature of the phosphor 2 to the attenuation characteristic correction unit 305. Note that step S401 may be performed in parallel with step S101 or step S302.

(C) In step S402, the attenuation characteristic correction unit 305 calculates a variation value ΔTc of the ambient temperature that is the difference between the measured value Tm of the ambient temperature of the phosphor 2 and the reference temperature Ts. In addition, the attenuation characteristic correction unit 305 reads the relationship between the variation amount ΔT of the ambient temperature and the variation amount Δτ of the fluorescence lifetime from the correction information storage unit 402. After that, the attenuation characteristic correcting unit 305 calculates the calculated value Δτc of the fluorescence lifetime variation based on the calculated value ΔTc of the ambient temperature variation and the relationship between the ambient temperature variation ΔT and the fluorescence lifetime variation Δτ. ₁ is calculated.

(D) In step S403, the attenuation characteristic correction unit 305 calculates the measured value τm in fluorescence lifetime, the calculated value Derutataushi ₁ of the variation amount of the fluorescence lifetime, taking the difference, a correction value .tau.c ₁ fluorescence lifetime. Thereafter, the attenuation characteristic correction unit 305 transmits the calculated fluorescence lifetime correction value τc ₁ to the differential pressure calculation unit 302. In step S <b> 404, the differential pressure calculation unit 302 reads a correlation acquired in advance between the fluorescence lifetime τ and the differential pressure ΔP between the first and second pressures P _O1 and P _O2 from the relationship storage unit 401. Next, the differential pressure calculation unit 302 calculates the first pressure P _O1 and the second pressure P _O2 based on the correlation between the fluorescence lifetime τ and the differential pressure ΔP and the fluorescence lifetime correction value τc _1. The differential pressure ΔP is calculated.

The pressure measurement system according to the fifth embodiment described above can correct variations in attenuation characteristics such as fluorescence lifetime τ due to variations in the ambient temperature T of the phosphor 2. Therefore, the pressure measurement system according to the fifth embodiment makes it possible to obtain the measured values of the first pressure P _O1 , the second pressure P _O2 , and the differential pressure ΔP more accurately.

(Sixth embodiment)
As shown in FIG. 25, the pressure measurement system according to the sixth embodiment measures the measurement value τ nm of the unmodulated fluorescence lifetime of the fluorescence before being modulated by the first and second pressure receiving elements 3 and 4. An unmodulated fluorescence lifetime measuring device 103 is further provided. The unmodulated fluorescence lifetime measuring device 103 includes, for example, a photodiode and an amplifier. Here, when the ambient temperature T of the phosphor 2 is the reference temperature Ts, the fluorescence fluorescence lifetime τ before being modulated by the first and second pressure receiving elements 3 and 4 is defined as the reference fluorescence lifetime τns.

In the sixth embodiment, the attenuation characteristic correction unit 305 corrects the fluorescence lifetime by calculating the difference between the measured value τnm of the unmodulated fluorescence lifetime and the reference fluorescence lifetime τns, as shown in the following equation (10). The quantity Δτc ₂ is calculated.
Δτc ₂ = τnm-τns (10)
Further, the attenuation characteristic correction unit 305 takes the difference between the fluorescence lifetime measurement value τm acquired by the attenuation characteristic measurement unit 301 and the fluorescence lifetime correction amount Δτc ₂ according to the following equation (11), and corrects the fluorescence lifetime correction value. τc ₂ is calculated.
τc ₂ = τm-Δτc ₂ ... (11)

In the sixth embodiment, the differential pressure calculation unit 302 correlates the fluorescence lifetime correction value τc ₂ calculated by the attenuation characteristic correction unit 305 with the fluorescence lifetime τ and the differential pressure ΔP stored in the relationship storage unit 401. Based on the relationship, a measured value of the differential pressure ΔP between the first and second pressures P _O1 and P _O2 is calculated.

Next, a pressure measuring method according to the sixth embodiment will be described using the flowchart shown in FIG.
(A) First, steps S101 to S302 are performed in the same manner as the pressure measurement method according to the fifth embodiment shown in FIG. In parallel with step S302, in step S501 of FIG. 26, the unmodulated fluorescence lifetime measuring instrument 103 shown in FIG. 25 is unmodulated before being modulated by the first and second pressure receiving elements 3 and 4. The fluorescence lifetime measurement value τ nm is measured. Further, the unmodulated fluorescence lifetime measuring device 103 transmits the measurement value τnm of the unmodulated fluorescence lifetime to the attenuation characteristic correcting unit 305.

(B) In step S502, the attenuation characteristic correction unit 305 calculates a fluorescence lifetime correction amount Δτc ₂ that is the difference between the measured value τnm of the unmodulated fluorescence lifetime and the reference fluorescence lifetime τns. In step S503, the attenuation characteristic correction unit 305 calculates the measured value τm of fluorescence lifetime, and the correction amount Derutataushi ₂ fluorescence lifetime, taking the difference, a correction value .tau.c ₂ fluorescence lifetime. Thereafter, the attenuation characteristic correction unit 305 transmits the calculated fluorescence lifetime correction value τc ₂ to the differential pressure calculation unit 302. In step S504, the differential pressure calculation unit 302 reads a correlation acquired in advance between the fluorescence lifetime τ and the differential pressure ΔP between the first and second pressures P _O1 and P _O2 from the relationship storage unit 401. Next, the differential pressure calculation unit 302 calculates the first pressure P _O1 and the second pressure P _O2 based on the correlation between the fluorescence lifetime τ and the differential pressure ΔP and the correction value τc ₂ of the fluorescence lifetime. The differential pressure ΔP is calculated.

The pressure measurement system according to the sixth embodiment described above can also correct variations in attenuation characteristics such as the fluorescence lifetime τ due to variations in the ambient temperature T of the phosphor 2. Therefore, the pressure measurement system according to the sixth embodiment makes it possible to obtain the measured values of the first pressure P _O1 , the second pressure P _O2 , and the differential pressure ΔP more accurately.

(Seventh embodiment)
Unlike the pressure measurement system according to the first embodiment illustrated in FIG. 1, the pressure measurement system according to the seventh embodiment illustrated in FIG. 27 includes a phosphor 42 that emits fluorescence in the first wavelength band, And a phosphor 52 that emits fluorescence in the second wavelength band. In this case, for example, an ultraviolet light emitting diode can be used for the light emitting element 1. Further, a blue phosphor can be used as the phosphor 42, and a green or red phosphor can be used as the phosphor 52. The fluorescence in the first wavelength band emitted from the phosphor 42 is given a first modulation depending on the first pressure P _O1 by the first pressure receiving element 3. Further, the second wavelength band fluorescence emitted from the phosphor 52 is given a second modulation depending on the second pressure P _O2 by the second pressure receiving element 4.

  The fluorescence of the first wavelength band given the first modulation is emitted from the end of the optical waveguide 12. The fluorescence of the second wavelength band given the second modulation is emitted from the end of the optical waveguide 22. Here, the fluorescence in the first wavelength band given the first modulation and the fluorescence in the second wavelength band given the second modulation are superimposed and received by the light receiving element 7 as coupled light. Is done. Other components of the pressure measurement system according to the seventh embodiment are the same as those in the first embodiment.

As shown in FIG. 28, the first wavelength filter 5 and the second wavelength filter 6 may be disposed at the respective end portions of the optical waveguide 12 and the optical waveguide 22. Similarly to the second embodiment, not only the differential pressure ΔP but also the first pressure P _O1 and the second pressure P _O2 may be measured in the seventh embodiment. Further, similarly to the third embodiment, in the seventh embodiment, the fluctuation of the light emission intensity of the light emitting element 1 may be corrected. Furthermore, similarly to the fourth to sixth embodiments, in the seventh embodiment, the variation in the ambient temperature T of the phosphors 52 and 62 may be corrected.

(Eighth embodiment)
The pressure measurement system according to the eighth embodiment shown in FIG. 29 is different from the pressure measurement system according to the first embodiment shown in FIG. 1 in that the excitation light emitted from the light emitting element 1 is not converted into fluorescence. Then, the light is propagated to the first pressure receiving element 3 and the second pressure receiving element 4 through the optical waveguide 11 and the optical waveguide 21, respectively. The first pressure receiving element 3 modulates the light intensity of the excitation light propagating to the optical waveguide 12 according to the first pressure P _O1 . The second pressure receiving element 4 modulates the light intensity of the excitation light propagating to the optical waveguide 22 according to the second pressure P _O2 .

  In the eighth embodiment, the first phosphor 62 and the second phosphor 72 are arranged at the respective end portions of the optical waveguide 12 and the optical waveguide 22. The first phosphor 62 and the second phosphor 72 may be made of the same phosphor that emits fluorescence including the first and second wavelength bands. Alternatively, the first phosphor 62 may be made of a fluorescent material that emits fluorescence in the first wavelength band, and the second phosphor 72 may be made of a fluorescent material that emits fluorescence in the second wavelength band. Moreover, the 1st fluorescent substance 62 and the 2nd fluorescent substance 72 may be integrated.

The fluorescence emitted by the first phosphor 62 passes through the first wavelength filter 5, and the fluorescence emitted by the second phosphor 72 passes through the second wavelength filter 6. The fluorescence transmitted through the first wavelength filter 5 and the fluorescence transmitted through the second wavelength filter 6 are overlapped and received by the light receiving element 7 as coupled light. Other components of the pressure measurement system according to the eighth embodiment are the same as those in the first embodiment. Similarly to the second embodiment, the first pressure P _O1 and the second pressure P _O2 may also be measured in the eighth embodiment. Further, similarly to the third embodiment, in the eighth embodiment, the fluctuation of the light emission intensity of the light emitting element 1 may be corrected. Furthermore, similarly to the fourth to sixth embodiments, in the eighth embodiment, the variation in the ambient temperature T of the first and second phosphors 62 and 72 may be corrected.

(Ninth embodiment)
In the pressure measurement system according to the ninth embodiment, as shown in FIG. 30, the first pressure receiving element 3 and the second pressure receiving element 4 are provided in the flow path 500. Further, the pressure measurement system according to the ninth embodiment is configured so that the CPU 300 applies the first and second pressures ΔP to the CPU 300 based on the differential pressure ΔP between the first and second pressures. A flow rate calculation unit 306 that calculates the flow rate Q is further provided.

For example, the flow rate Q of the fluid flowing between the first pressure receiving element 3 and the second pressure receiving element 4 in which the differential pressure ΔP is generated is given by the following equation (12).
Q = C × ΔP ^1/2 ... (12)
C represents a constant obtained in advance by density calibration or the like. The flow rate calculation unit 306 determines the first pressure receiving element 3 and the second pressure receiving element 4 based on the measured value of the differential pressure ΔP calculated by the differential pressure calculation unit 302 and the relationship between the differential pressure ΔP and the flow rate Q. A measured value of the flow rate Q of the fluid flowing between them is calculated.

According to the pressure measurement system according to the ninth embodiment, the fluid flowing between the first pressure receiving element 3 and the second pressure receiving element 4 based on the fluorescence attenuation characteristics such as the fluorescence lifetime τ. The flow rate Q can be calculated easily and accurately. Similarly to the second embodiment, also in the ninth embodiment, the first pressure P _O1 and the second pressure P _O2 may be measured. Further, similarly to the third embodiment, in the ninth embodiment, the fluctuation of the light emission intensity of the light emitting element 1 may be corrected. Furthermore, similarly to the fourth to sixth embodiments, in the ninth embodiment, the variation in the ambient temperature T of the phosphor 2 may be corrected.

(Other embodiments)
As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques should be apparent to those skilled in the art. For example, in the light receiving element 7 shown in FIG. 17 or the like, a response delay (a phenomenon in which an output does not immediately disappear even when input light such as excitation light disappears) may occur. Therefore, as shown in FIG. 31, compared with the fluorescence intensity measured immediately after the light emitting element 1 that emits the excitation light is turned off, after a time longer than the previously measured response delay time (of the entire sensor). The time required to decrease to 1 / e or a predetermined ratio of fluorescence intensity may be defined as the fluorescence lifetime τ of the phosphor 2. Further, when measuring the fluorescence intensity, an offset generated by signal amplification in the processing unit 8 shown in FIGS. 1 and 17 may be corrected. Further, the phosphor 2 may be stored in a thermostatic bath in order to suppress fluctuations in the ambient temperature T of the phosphor 2. Thus, it should be understood that the present invention includes various embodiments and the like not described herein.

DESCRIPTION OF SYMBOLS 1 Light emitting element 2,42,52,62,72 Phosphor 3,83 1st pressure receiving element 4,84 2nd pressure receiving element 5,15 1st wavelength filter 6 2nd wavelength filter 7 Light receiving element 8 Processing part DESCRIPTION OF SYMBOLS 11, 12, 21, 22 Optical waveguide 27 Reflective film 31 Lens 40 Base part 43,143 Case 50,150 Pressure sensitive film 60 Holder 70 Opening valve 90 Current supply control part 91 Light emission detector 92 Light emission intensity correction part 101 Temperature controller 102 Thermometer 103 Unmodulated fluorescence lifetime measuring device 127 Diffraction element 160 Ventilation hole 301 Attenuation characteristic measuring unit 302 Differential pressure calculating unit 303 Light intensity measuring unit 304 Pressure calculating unit 305 Attenuating characteristic correcting unit 306 Flow rate calculating unit 321 Input device 322 Output device 323 Program storage device 324 Temporary storage device 400 Data storage device 401 Relation storage unit 402 Correction information storage unit 500 Channel

Claims (55)

At least one phosphor that emits fluorescence in a first wavelength band and fluorescence in a second wavelength band different from the first wavelength band;
A first pressure-receiving element that receives a first pressure and applies a first modulation to at least the fluorescence in the first wavelength band;
A second pressure-receiving element that receives a second pressure and applies a second modulation to at least the fluorescence in the second wavelength band;
An attenuation characteristic measuring unit that measures an attenuation characteristic of the combined light of the fluorescence in the first wavelength band given the first modulation and the fluorescence in the second wavelength band given the second modulation;
A differential pressure calculation unit that calculates a differential pressure between the first and second pressures based on the damping characteristics;
Pressure measuring system.   The pressure measurement system according to claim 1, further comprising a relationship storage unit that stores a previously acquired relationship between the damping characteristic and the differential pressure. The differential pressure calculation unit
Based on the attenuation characteristics, the amount of fluorescence in the first wavelength band given the first modulation and the amount of fluorescence in the second wavelength band given the second modulation, Calculate the light intensity ratio,
Calculating a differential pressure between the first and second pressures based on the light amount ratio;
The pressure measurement system according to claim 1.   The pressure measurement system according to claim 3, further comprising a relationship storage unit that stores a previously acquired relationship between the light amount ratio and the differential pressure. A first wavelength filter that transmits fluorescence in the first wavelength band given the first modulation and shields fluorescence in the second wavelength band given the first modulation;
A second wavelength filter that transmits fluorescence in the second wavelength band given the second modulation and shields fluorescence in the first wavelength band given the second modulation;
The pressure measurement system according to any one of claims 1 to 4, further comprising:   The pressure measurement system according to any one of claims 1 to 5, wherein the first wavelength band and the second wavelength band have different centroid wavelengths.   The pressure measurement system according to any one of claims 1 to 6, wherein the first wavelength band and the second wavelength band have different bandwidths.   The pressure measurement system according to any one of claims 1 to 7, further comprising an attenuation characteristic correction unit that corrects a variation in the attenuation characteristic based on a variation in an ambient temperature of the at least one phosphor.   The pressure measurement system according to any one of claims 1 to 7, further comprising a temperature controller configured to make an ambient temperature of the at least one phosphor constant.   The pressure measurement system according to any one of claims 1 to 7, further comprising a thermostatic chamber for storing the at least one phosphor. A light emitting element that emits light;
The first pressure-receiving element receives the first pressure and applies a first modulation to the light;
11. The pressure measurement system according to claim 1, further comprising a pressure calculation unit configured to calculate the first pressure based on a light intensity of the light subjected to the first modulation.   The pressure measurement system according to claim 11, further comprising a relationship storage unit that stores a previously acquired relationship between a light intensity of the light subjected to the first modulation and the first pressure.   The pressure measurement system according to claim 11, further comprising a light emission intensity correction unit that corrects a variation in light intensity of the light.   The flow rate calculation part which calculates the flow volume of the fluid which gave the said 1st and 2nd pressure based on the differential pressure of the said 1st and 2nd pressure is further provided in any one of Claims 1 thru | or 13. Pressure measurement system. Emitting fluorescence of a first wavelength band and fluorescence of a second wavelength band different from the first wavelength band;
Applying at least a first modulation dependent on a first pressure to the fluorescence in the first wavelength band;
Providing at least a second modulation dependent on a second pressure on the fluorescence in the second wavelength band;
Measuring the attenuation characteristics of the combined light of the fluorescence in the first wavelength band given the first modulation and the fluorescence in the second wavelength band given the second modulation;
Calculating a differential pressure between the first and second pressures based on the damping characteristic;
A pressure measuring method including:   The pressure measurement method according to claim 15, further comprising preparing a previously acquired relationship between the damping characteristic and the differential pressure. Calculating the differential pressure is based on the attenuation characteristics, and the amount of fluorescence in the first wavelength band given the first modulation, and the second quantity given the second modulation. Calculating the ratio of the amount of fluorescence in the wavelength band and the amount of fluorescence,
The pressure measurement method according to claim 15, wherein the differential pressure is calculated based on the light amount ratio.   The pressure measurement method according to claim 17, further comprising preparing a previously acquired relationship between the light amount ratio and the differential pressure. Transmitting fluorescence in the first wavelength band given the first modulation and shielding the fluorescence in the second wavelength band given the first modulation;
Transmitting fluorescence of the second wavelength band given the second modulation and shielding the fluorescence of the first wavelength band given the second modulation;
The pressure measurement method according to claim 15, further comprising:   The pressure measuring method according to any one of claims 15 to 19, wherein the first wavelength band and the second wavelength band have different centroid wavelengths.   The pressure measurement method according to any one of claims 15 to 20, wherein the first wavelength band and the second wavelength band have different bandwidths.   The pressure measurement method according to any one of claims 15 to 21, further comprising correcting a variation in the attenuation characteristic based on a variation in an ambient temperature of the at least one phosphor.   The pressure measurement method according to any one of claims 15 to 21, further comprising making an atmospheric temperature of the at least one phosphor constant. Emitting light,
Providing the light with the first modulation;
Calculating the first pressure based on the light intensity of the light provided with the first modulation;
The pressure measurement method according to claim 15, further comprising:   25. The pressure measurement method according to claim 24, further comprising preparing a previously acquired relationship between light intensity of the light subjected to the first modulation and the first pressure.   The pressure measurement method according to claim 24, further comprising correcting a variation in light intensity of the light.   27. The pressure according to any one of claims 15 to 26, further comprising calculating a flow rate of a fluid that has applied the first and second pressures based on a differential pressure between the first and second pressures. Measuring method. A light emitting element that emits light;
A first pressure-receiving element that receives a first pressure and applies a first modulation to the light;
A second pressure receiving element that receives a second pressure and applies a second modulation to the light;
A first phosphor that is irradiated with light having the first modulation and emits fluorescence of at least a first wavelength band;
A second phosphor that is irradiated with light having the second modulation and emits fluorescence of at least a second wavelength band different from the first wavelength band;
An attenuation characteristic measurement unit that measures attenuation characteristics of the combined light of the fluorescence in the first wavelength band and the fluorescence in the second wavelength band;
A differential pressure calculation unit that calculates a differential pressure between the first and second pressures based on the damping characteristics;
Pressure measuring system.   29. The pressure measurement system according to claim 28, further comprising a relationship storage unit that stores a previously acquired relationship between the damping characteristic and the differential pressure. The differential pressure calculation unit
Based on the attenuation characteristics, a light amount ratio between the amount of fluorescence in the first wavelength band and the amount of fluorescence in the second wavelength band is calculated,
Calculating a differential pressure between the first and second pressures based on the light amount ratio;
The pressure measurement system according to claim 28.   The pressure measurement system according to claim 30, further comprising a relationship storage unit that stores a previously acquired relationship between the light amount ratio and the differential pressure. A first wavelength filter that transmits fluorescence in the first wavelength band derived from the first phosphor and shields fluorescence in the second wavelength band derived from the first phosphor;
A second wavelength filter that transmits fluorescence of the second wavelength band derived from the second phosphor and shields fluorescence of the first wavelength band derived from the second phosphor;
The pressure measurement system according to any one of claims 28 to 31, further comprising:   The pressure measurement system according to any one of claims 28 to 32, wherein the first wavelength band and the second wavelength band have different centroid wavelengths.   The pressure measurement system according to any one of claims 28 to 33, wherein the first wavelength band and the second wavelength band have different bandwidths.   35. The pressure measurement system according to any one of claims 28 to 34, further comprising an attenuation characteristic correction unit that corrects a variation in the attenuation characteristic based on a variation in the ambient temperature of the first and second phosphors.   35. The pressure measurement system according to any one of claims 28 to 34, further comprising a temperature controller that makes the ambient temperature of the first and second phosphors constant.   The pressure measurement system according to any one of claims 28 to 34, further comprising a thermostatic chamber for storing the first and second phosphors.   38. The pressure measurement system according to any one of claims 28 to 37, further comprising a pressure calculation unit that calculates the first pressure based on light intensity of the light subjected to the first modulation.   39. The pressure measurement system according to claim 38, further comprising a relationship storage unit that stores a previously acquired relationship between light intensity of the light subjected to the first modulation and the first pressure.   40. The pressure measurement system according to claim 38 or 39, further comprising a light emission intensity correction unit that corrects a variation in light intensity of the light.   41. The pressure measurement system according to any one of claims 28 to 40, wherein the first and second phosphors are integrated.   42. The flow rate calculation unit according to any one of claims 28 to 41, further comprising a flow rate calculation unit configured to calculate a flow rate of the fluid to which the first and second pressures are applied based on a differential pressure between the first and second pressures. Pressure measurement system. Emitting light,
Providing the light with a first modulation that depends on a first pressure;
Providing the light with a second modulation that depends on a second pressure;
Exciting the fluorescence of at least the first wavelength band with the light subjected to the first modulation;
Exciting the fluorescence of at least a second wavelength band different from the first wavelength band with the light subjected to the second modulation;
Measuring the attenuation characteristics of the combined light of the fluorescence in the first wavelength band and the fluorescence in the second wavelength band;
Calculating a differential pressure between the first and second pressures based on the damping characteristic;
A pressure measuring method including:   44. The pressure measurement method according to claim 43, further comprising preparing a previously acquired relationship between the attenuation characteristic and the differential pressure. Calculating the differential pressure includes calculating a light amount ratio between the amount of fluorescent light in the first wavelength band and the amount of fluorescent light in the second wavelength band based on the attenuation characteristics;
44. The pressure measurement method according to claim 43, wherein the differential pressure is calculated based on the light amount ratio.   46. The pressure measurement method according to claim 45, further comprising preparing a previously acquired relationship between the light amount ratio and the differential pressure. Transmitting fluorescence of the first wavelength band derived from the first phosphor and shielding fluorescence of the second wavelength band derived from the first phosphor;
Transmitting the fluorescence of the second wavelength band derived from the second phosphor and shielding the fluorescence of the first wavelength band derived from the second phosphor;
The pressure measurement method according to any one of claims 43 to 46, further comprising:   The pressure measurement method according to any one of claims 43 to 47, wherein the first wavelength band and the second wavelength band have different centroid wavelengths.   49. The pressure measurement method according to any one of claims 43 to 48, wherein the first wavelength band and the second wavelength band have different bandwidths.   The pressure measurement method according to any one of claims 43 to 49, further comprising correcting a variation in the attenuation characteristic based on a variation in the ambient temperature of the first and second phosphors.   The pressure measurement method according to any one of claims 43 to 49, further comprising making the ambient temperature of the first and second phosphors constant.   52. The pressure measurement method according to any one of claims 43 to 51, further comprising calculating the first pressure based on a light intensity of the light given the first modulation.   53. The pressure measurement method according to claim 52, further comprising preparing a previously acquired relationship between light intensity of the light subjected to the first modulation and the first pressure.   54. The pressure measurement method according to any one of claims 43 to 53, further comprising correcting a variation in light intensity of the light.   55. The pressure according to any one of claims 43 to 54, further comprising calculating a flow rate of a fluid that has applied the first and second pressures based on a differential pressure between the first and second pressures. Measuring method.

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