JP2001194304A - Element for measuring oxygen concentration, its manufacturing method, and sensor equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an element for measuring oxygen concentration, its manufacturing method, and an oxygen sensor equipped with the same, having high measurement sensitivity and accuracy, high resistance to a severe measurement environment such as various chemical solvents, and capable of performing stable measurement for a long period of time. SOLUTION: A fluorescent material having fluorescence intensity reduced by the existence of oxygen molecules and an oxygen-permeable liquid compound are mixed together to be uniformly dispersed in a porous filter and then staticized on a substrate glass, Its surface is covered by a fluorescence-reflection/ external-light cut-off layer for preventing fluorescence/excited light from leaking out of a fluorescence detection part to the exterior and cutting off external light, thus forming the element for measuring oxygen concentration. The oxygen sensor uses this element as a fluorescence detection part, and is adapted so that excited light emitted from an ultraviolet emitting diode is applied to a fluorescence generating layer via optical fiber, and that generated fluorescence is received by a photodiode via optical fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxygen concentration measuring element for measuring oxygen concentration, and more particularly to a so-called "fluorescence quenching reduction" in which the intensity of fluorescence emitted by photoexcitation is reduced according to the oxygen concentration to be measured. And a device for measuring oxygen concentration based on The invention further relates to a method for producing such an element for measuring oxygen concentration and to an oxygen concentration sensor comprising such an element for measuring oxygen concentration.

[0002]

2. Description of the Related Art Conventionally, sensors based on various principles have been actually used as sensors for measuring oxygen concentration. For example, utilizing the property of oxygen as an electron acceptor,
Detects current flowing during electrochemical reduction of oxygen using an electrode covered with an oxygen permeable membrane, or detects oxygen using oxygen ion conductivity based on the action of oxygen concentration cells in ceramics at high temperatures What is known is.
Furthermore, in recent years, there has been proposed a measurement of an oxygen concentration using a “fluorescence quenching phenomenon” in which the intensity of fluorescence emitted by photoexcitation is reduced according to the concentration of oxygen present. An oxygen sensor based on this phenomenon can measure 0 to 100% oxygen partial pressure in gas and liquid, and can measure continuously for a long period of time without using an electrolyte or an oxygen permeable membrane. It has many excellent properties, such as being less affected and being able to measure even in a stationary solution. For example,
Japanese Patent Application Laid-Open No. 6-180287 discloses a method for producing an oxygen sensor element as described above by mixing a fluorescent reagent in silicone oil, and then crosslinking and fixing the mixture. Further, JP-A-10-132742 discloses a method of mixing a fluorescent reagent as fine crystals.

[0003]

The oxygen quenching element of the above-described fluorescence quenching type oxygen concentration measuring sensor comprises a polycyclic aromatic molecule or a heterocyclic aromatic molecule such as decacyclene, perylene, tetracene or benzanthracene. , Silicon, polyethylene, polypropylene, polystyrene, Teflon and the like.
For this reason, various methods have been proposed, but it has been difficult to immobilize the amount of a fluorescent reagent such as decacyclene that generates sufficient fluorescence to enable measurement with practical accuracy and sensitivity. It has also been proposed to disperse decacyclene in silicone oil and then heat it to produce a gel-like fluorescent layer. However, in this case, the sensitivity is low and the dispersion of fluorescent molecules is not uniform. The variation in characteristics was large. Even with the method using dekacyclene as a fine crystal, variation in characteristics could not be sufficiently reduced.

Further, it is necessary to keep the thickness and the shape of the fluorescent layer and the light-shielding layer provided on the fluorescent layer constant.
It is extremely difficult to adjust these accurately with the conventional method, and the variation in characteristics due to the film pressure and shape is large.

Accordingly, it is an object of the present invention to provide an element for measuring oxygen concentration which has higher sensitivity and does not vary in characteristics, and a method for manufacturing the same. Another object of the present invention is to provide such an oxygen concentration measuring element, a fluorescence detection unit for receiving fluorescence, and a signal processing for processing an output signal from the fluorescence detection unit and outputting a signal indicating an oxygen concentration. It is an object of the present invention to provide an oxygen sensor which has a unit and can be used stably for a long period of time and has no variation in characteristics.

[0006]

An oxygen concentration measuring element according to the present invention is provided on a substrate through which excitation light and fluorescence are transmitted, and provided on the substrate. A polycyclic aromatic or heterocyclic aromatic fluorescent substance exhibiting a decrease is uniformly dispersed and fixed in a porous filter, and a fluorescent generating layer is provided on the fluorescent generating layer. It is characterized by comprising a coating layer that reflects emitted fluorescence, blocks external light, transmits oxygen, and protects the fluorescence generating layer. In the present invention,
The above-mentioned coating layer may be configured as a single layer having all the functions described above, or may be a single layer having the respective functions.
Fluorescent reflection / external light blocking layer, which consists of two independent layers laminated or reflects fluorescence emitted from the fluorescence generating layer, blocks external light and transmits oxygen, and protection with a protective function It can be constituted by laminating layers. In addition, the above-described porous filter needs to have a uniform thickness, a uniform oxygen permeability, and a uniform porosity.
In such a filter, the fluorescent material enters many fine holes in the filter, and is dispersed very uniformly and stably exists.

Further, the method for manufacturing an oxygen concentration measuring element according to the present invention is directed to a method for producing a polycyclic aromatic or heterocyclic aromatic fluorescent substance which shows a decrease in fluorescence intensity in response to oxygen concentration under excitation light. The powder is treated and refined, and the dispersion of the treated and refined fluorescent substance powder dispersed in an oxygen-permeable liquid polymer is applied to a porous filter, allowed to penetrate, and then heated to cause the fluorescent substance to pass through the filter. To form a fluorescent light-generating layer, and fix this fluorescent light-emitting layer on a substrate, reflect the fluorescent light emitted from the fluorescent light-emitting layer, block external light, transmit oxygen, and It is characterized by providing a coating layer for protecting the generation layer. This coating layer
It can be formed as a single layer, or can be formed by laminating two or three layers.

Further, an oxygen sensor according to the present invention comprises a light source for emitting excitation light, a substrate for transmitting the excitation light from the light source, and a substrate provided on the substrate. A polycyclic aromatic or heterocyclic aromatic fluorescent substance exhibiting a decrease in fluorescence intensity is uniformly dispersed and fixed in a porous filter, and a fluorescent generation layer is provided on the fluorescent generation layer. An oxygen measurement element comprising a coating layer that reflects fluorescence emitted from the generation layer, blocks external light, transmits oxygen, and protects the fluorescence generation layer, and emits the fluorescence emitted from the fluorescence generation layer. It is characterized by comprising a fluorescence detection unit that receives light via the substrate, and a signal processing unit that processes an output signal from the fluorescence detection unit and outputs a signal indicating an oxygen concentration.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a representative example of a method for manufacturing an element for measuring oxygen concentration according to the present invention will be described. First, the fluorescent substance is treated and purified as follows. 5g of dekacyclene and 3
Put 00 cc of aniline into a triangular flask and mix and mix well. The decacyclene-aniline mixture is heated and mixed at a temperature of 60 ° C. for 2 hours. Perchloric acid is added to the decacyclene-aniline mixture to adjust the pH to 3.0. Let stand for 8 hours to allow insoluble material to settle. The supernatant of the decacyclene-aniline mixture is filtered through a 500 mesh stainless steel filter net. The filtrate is centrifuged, for example, at 2,000 rpm for 2 hours or more, and at 5,000 rpm for 30 hours.
Separate for 10 minutes or more at 10,000 rpm for more than 10 minutes. The supernatant of the centrifuged liquid is discarded, the remaining precipitate and acetone are mixed and stirred, and the mixture is centrifuged again to separate. Further, such centrifugation is repeated twice.
The substance precipitated by the centrifuge is dried at 60 ° C. for 5 hours to obtain a treated and purified fluorescent substance.

Next, an element for oxygen measurement is manufactured using the fluorescent substance treated and purified as described above. First, a fluorescence generating layer is prepared. A fine powder of the processed and purified fluorescent substance is added to a solution of “CYTOP (registered trademark of Asahi Glass)” which is a liquid oxygen-permeable polymer, and mixed and stirred. As shown in FIG. 1, two drops of the above-mentioned fluorescent substance-oxygen permeable compound mixture liquid were dropped on a substrate glass (ground glass surface) 1 and the oxygen permeable compound having a thickness of 20-100 μm and a mesh 10
A -100 nm fluorine-based compound is placed on the fluorine-based compound, and the liquid is impregnated into the fluorine-based compound, and the air between the substrate glass and the fluorine-based compound is expelled and adhered. In this state, air dry naturally for 12 hours, and then use a dryer at 100 ° C for 2 hours.
After drying for a time, the fluorescence generating layer 2 is obtained.

Next, the fluorescent reflection layer 3 is formed. The titanium oxide powder is added to the CYTOP solution and mixed and stirred. A mixture of titanium oxide and CYTOP is applied to the surface of the fluorescence generating layer 2 formed on the substrate glass 1 with a fine brush or the like, air-dried, applied again, air-dried for 6 hours or more, and then dried by a dryer. After drying at 150 ° C. for 2 hours, the fluorescent reflection layer 3 is formed. 700 kg / c pressure to drive out air
The hydraulic press is performed under the conditions of m ² , 6 minutes or more.

Next, an external light blocking layer 4 is formed. Add the metal titanium powder to the CYTOP solution and mix and stir. To a fluorine-based compound that is easy to peel off the coating film, apply a mixture of metal titanium and CYTOP twice with a fine brush and let it dry naturally.
Peel off the coating. A CYTOP solution is applied to the surface of the fluorescence reflection layer 3 formed on the fluorescence generation layer 2 formed on the surface of the substrate glass 1 and dried for about 30 minutes to make it a semi-dry state. The coating film peeled off as described above is put thereon and adhered, and is naturally dried for 12 hours. Then, in the dryer, 2
After drying for an hour, the external light blocking layer 4 is obtained. In order to drive out the air in the gap, a hydraulic press is performed under the conditions of a pressure of 700 kg / cm ² and at least 6 minutes.

Thus, the element for measuring oxygen concentration shown in FIG. 1 is obtained. This oxygen concentration measuring element has a thickness of 20 in order from the outside (the side in contact with the oxygen to be measured).
μm protective layer 5, external light blocking layer 4 having a thickness of 5 μm,
It is composed of a fluorescent reflection layer 3 having a thickness of 20 μm, a fluorescence generation layer 2 having a thickness of 20 μm, and a substrate glass 1 having a thickness of 2 mm. Hereinafter, each layer will be described.

The protective layer 5 is formed by impregnating a fluorine-based compound solution with a fluorine-based compound, heat-treating the resultant, and press-compressing it. This allows water, steam, oil, alcohol, etc.
Completely prevent liquid infiltration. This is because even if the liquid infiltrates even a little, the transfer of oxygen gas becomes worse, or the optical characteristics change, resulting in extremely poor response characteristics and sensitivity.

The external light blocking layer 4 is obtained by mixing fine metal titanium powder and a fluorine compound solution, applying the mixed solution, and drying the mixture. The light intensity of the fluorescent light is very weak, and if light enters from the outside, it causes disturbance noise and measurement error occurs, making the measurement unstable. Therefore, it is necessary to block external light with this layer.

The fluorescent reflection layer 3 is obtained by mixing a fine powder of titanium oxide and a solution of a fluorine-based compound, applying the mixture, and drying the mixture. Even if the internal excitation light or fluorescence leaks to the outside, a measurement error occurs, but this layer needs to prevent light leakage from the inside. By increasing the light collection efficiency by reflecting the excitation light and the fluorescent light with this white layer, the sensitivity can be made three times or more higher than when no sensitivity is applied.

The fluorescent layer 2 is made of a fluorescent material having an outer diameter of 13 mm.
It is uniformly dispersed and immobilized with a liquid fluorine compound in a fluorine compound having a thickness of 20 μm and a mesh of 40 nm.

The substrate glass 1 has an outer diameter of 10 mm and a thickness of 2 mm, and can be stably measured using quartz glass, heat-resistant glass, sapphire glass or the like.

FIG. 2 shows the structure of an oxygen sensor of the oxygen sensor according to the present invention, in which the above-described oxygen concentration measuring element 10 is incorporated. The upper part of FIG. 2 is the part that comes into contact with the oxygen to be measured. The oxygen concentration measurement element 10 composed of the substrate glass 1, the fluorescence generation layer 2, the fluorescence reflection layer 3, the external light blocking layer 4, and the protection layer 5 is made of stainless steel (SUS31
6) and is fixed to the tip of the probe holder 12.

In order to fix the oxygen concentration measuring element 10 of the fluorescence detecting section to the tip of the sensor cap 11, an epoxy-based adhesive is prepared by mixing a base material and a curing agent, placing the mixture in a vacuum bell jar, and sucking it for 15 minutes with a vacuum pump. Perform degassing. The defoamed adhesive is applied to the inner surface of the sensor cap 11, and the substrate glass 1 and the sensor cap 11 are adhered. 50 in the dryer
Reference numeral 12 indicates an adhesive layer formed by drying at 5 ° C. for 5 hours or more. In this manner, the sensor cap 11 having the oxygen concentration measuring element fixed to the tip is fitted to the probe holder 12.
At this time, an O-ring 13 is inserted between the back surface of the substrate glass 1 and the tip end surface of the probe holder 12.

FIG. 3 shows the overall configuration of the oxygen sensor according to the present invention. As described above, inside the probe holder 12 having the oxygen concentration measuring element fixed to the tip,
A light guide rod LGR having one end in contact with the back surface of the glass substrate 1 is arranged, and a pair of optical fibers 14 and 15 are extended so that one end is in contact with the other end, respectively, and the other end of one optical fiber 14 ( The light-emitting diode (light-incident side) is opposed to a light-emitting diode 17 that generates ultraviolet light via a blue filter 16. The other end (outgoing side) of the other optical fiber 15 is opposed to the photodiode 19 via the green filter 18.

On the emission side of the blue filter 16, a photodiode 20 for compensating excitation light is provided at a position off the optical axis, and its output is fed back to an arithmetic and control circuit 21 for driving the light emitting diode 17. This operation
A reference signal is supplied to a control circuit 21 from a central processing unit (CPU) 22, and the reference signal and the photodiode 2
The driving current of the light emitting diode 17 is controlled based on the deviation from the signal from 0, so that the excitation light having a constant brightness is always emitted.

In accordance with the concentration of oxygen to be measured, the surface of the oxygen concentration measuring element 10 enters the fluorescence generating layer 2 through the protective layer 5 having oxygen permeability, the external light blocking layer 4 and the fluorescent reflecting layer 3, respectively. Oxygen enters. This fluorescence generating layer 2 includes
Ultraviolet light emitted from the light emitting diode 17 is irradiated through the optical fiber 14 so that fluorescence is generated. However, the amount of fluorescence decreases in inverse proportion to the oxygen concentration due to the fluorescence quenching phenomenon due to the entered oxygen. This fluorescent light is passed through the optical fiber 15 attached to the lower part of the substrate glass 1 and the photodiode 19
To receive light. The wavelength of the excitation light emitted from the light emitting diode 17 is 385 nm, the bandwidth is 20 nm, and the wavelength of the fluorescence quenched by oxygen is 510 nm, and the bandwidth is 20 nm.

After the output signal of the photodiode 19 is amplified by the preamplifier 23, the sample / hold circuit 24
, And obtains the obtained sample value by the operational amplifier 2.
5 and further amplified by the amplifier 26 on the instrument body side,
The signal is converted into a digital signal by the A / D converter 27 and
Feed to 2. The CPU 22 can calculate the oxygen concentration by processing the output signal of the photodiode 19 thus supplied.

A temperature sensor 31 is also provided at the tip of the probe holder 12, and its output signal is amplified by an amplifier 32 and sent to the main body of the instrument, converted into a digital signal by an A / D converter 33, and then supplied to the CPU 22. I do. The correlation between the oxygen concentration and the temperature is obtained in advance, and when the CPU 22 calculates the oxygen concentration by calculation, the correction based on the temperature detected by the temperature sensor 31 can be performed to improve the measurement accuracy.

The signal representing the oxygen concentration obtained as described above is displayed on the liquid crystal display 41 connected to the CPU 22, converted into an analog signal by the D / A converter 42 and output, and output from the RS-232C interface. The signal is output as a digital signal via 43.

Next, various characteristics of the above-described embodiment will be described, and differences in characteristics from the comparative example will be described. First, the sensitivity characteristics will be described. Sample 1 is a sensor chip having a thickness of 0.02 mm formed according to the present embodiment. As sample No. 2, a solution of decacyclene in aniline as a sensor chip was removed by a method of mixing fluorescent reagents as fine crystals disclosed in JP-A-10-132742, and the precipitate was removed. A sensor chip that has crystallized, washed and purified with acetone and ethanol, mixed in a liquid silicone polymer, dissolved, polymerized and cured to a predetermined shape to create a 0.10 mm-thick fluorescent-emitting layer. Got ready. As a sample No. 3, a sensor chip prepared by dispersing decacyclene powder in a silicone polymer as it is was prepared. As a sample No. 4, a fluorescent material obtained by recrystallizing a precipitate generated when decacyclene was dissolved in aniline was used. A sensor chip that was mixed, dissolved, and cured in a liquid silicone polymer was prepared. The thickness of the fluorescence generating layers of these samples No. 3 and No. 4
It was 0.10 mm. The difference between the signal intensity measured after 2 hours or more in a nitrogen atmosphere (oxygen concentration 0%) at 25 ° C. and the signal intensity measured in air (oxygen concentration 20.9%) was determined. It is shown in Table 1.

[0028]

[Table 1] From Table 1, it can be seen that the sensitivity of Sample No. 1 according to the present invention is more than twice as high as Sample No. 2 and more than 50 times higher than Sample No. 3. Considering that Sample No. 1 has a thickness of 0.02 mm and only 20% of other samples, the sensitivity of Sample No. 1 per film thickness is No. 2
More than 10 times higher than that of sample No. 4 and 2 times higher than sample No. 4.
It turns out that it is 50 times or more higher.

Next, results of a test for long-term stability are shown. As the measurement conditions, the above-mentioned sample Nos. 1 to
No. 4 was maintained at a temperature of 20 ° C. in the air, and the time-dependent change of the signal intensity, that is, the drift rate was measured. Table 2 shows the results.

[0030]

[Table 2]

From this graph, in sample No. 1 which is an embodiment according to the present invention, the fluctuation in sensitivity is extremely small over a long period of time, and the drift rate after 2000 hours is 0.0%. Sample No. 2 had a drift rate of 0.1% at 179 hours, while Sample No. 1 according to the present invention had a drift rate of 0.0% even at 2000 hours, which is 10 times or more the time, and Sample No. 1 Has remarkably excellent stability. Furthermore, as can be seen from Table 1, Sample No. 4 has a large sensitivity itself, but shows a large drift rate and lacks stability.

Embodiment 2 In the embodiment 1 shown in FIG. 1, the structure of the fluorescent reflection layer 3 and the external light blocking layer 4 is employed. However, as shown in FIG. 53 can also be formed. That is, the fluorescence reflection layer has a function of mainly reflecting the fluorescence emitted from the fluorescence generation layer on the side of the fluorescence generation layer, but also has a function of blocking external light on the side of the test substance. Therefore, in the first embodiment, the fluorescent reflection layer 3
FIG. 4 shows a structure in which the light shielding layer 4 and the external light blocking layer 4 are laminated.
As shown in (1), it is of course possible to form a single layer as the fluorescence reflection / external light blocking layer 53 so as to fulfill the function of reflecting fluorescence emitted from the fluorescence generating layer 52 and the function of blocking external light. .

Embodiment 3 In Embodiment 1 shown in FIG. 1, the structure includes the fluorescent reflection layer 3, the external light blocking layer 4, and the protective layer 5, but as shown in FIG.
This can be integrally formed as the coating layer 63. That is, a substance having a function of reflecting fluorescence and blocking external light is applied to the fluorine-based compound filter used as the protective layer 5 in Example 1, and the coating layer 63 is integrally formed. Specifically, a metal titanium-cytop mixture is applied twice to a fluorine-based compound filter having a thickness of 70 to 80 μm with a thin brush or the like, and air-dried. The CYTOP solution is applied on the fluorescence generating layer 62 formed on the surface of the substrate glass 61, and dried for about 30 minutes to make it a semi-dry state. Then, the above-mentioned filter is put thereon and adhered, and air-dried for 12 hours. After that, the coating layer 63 is obtained by drying with a dryer for 2 hours. In order to drive out the air gap,
A hydraulic press is performed under the conditions of a pressure of 700 kg / cm ² and 6 minutes or more. The coating layer 63 finally becomes about 20 to 30 μm by the hydraulic press. As shown in FIG.
A thin titanium metal-cytop layer 64 is formed on the upper part of the substrate (test substance side).

[0034]

According to the oxygen concentration measuring element of the present invention, a fluorescent substance is uniformly dispersed in a porous filter and fixed stably, so that sensitivity and accuracy are high and stable over a long period of time. It works. In addition, the thickness and shape of the fluorescence generation layer, the coating layer, and the fluorescence reflection / external light blocking layer are highly reproducible, and variations in characteristics can be extremely reduced. In addition, an oxygen sensor including an oxygen concentration measuring element having such excellent characteristics has high sensitivity and can perform stable measurement continuously for a long period of time.
Furthermore, according to the method of the present invention for producing such an element for measuring oxygen concentration, an element having excellent characteristics can be produced with extremely high reproducibility.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an element for measuring oxygen concentration of Example 1 according to the present invention.

FIG. 2 is a cross-sectional view showing a bonded state between an oxygen concentration measuring element and a sensor cap.

FIG. 3 is a diagram showing an overall configuration of an oxygen sensor according to the present invention.

FIG. 4 is a sectional view showing a configuration of an element for measuring oxygen concentration according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of an oxygen concentration measuring element according to a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate glass, 2 Fluorescence generation layer, 3 Fluorescence reflection layer, 4 External light blocking layer, 5 Protective layer, 10 Element for oxygen concentration measurement, 11 Sensor cap, 12 Probe holder, 13 Adhesive layer, 14, 15 Optical fiber,
16 blue filter, 17 light emitting diode,
18 green filter, 19 photodiode,
Reference Signs List 20 photodiode for excitation light compensation, 21 operation / control circuit, 22 CPU, 23 preamplifier,
24 S-H amplifier, 25 F amplifier, 26 amplifier, 27, 33 A / D converter, 41 liquid crystal display, 42 D / A converter, 43 RS-232C interface, 51 substrate glass, 52 fluorescence generation layer, 53 fluorescence reflection / External light blocking layer, 54 protective layer,
61 substrate glass, 62 fluorescence generating layer, 63 coating layer

Continuation of the front page (72) Inventor Kozo Inoue 1-10-5 Iwamotocho, Chiyoda-ku, Tokyo F-term in the Automatic System Research Co., Ltd. (Reference) 2G043 AA01 BA09 CA01 EA01 FA03 GA08 GB01 GB16 GB21 HA05 JA03 KA02 KA03 LA01 MA01 2G059 AA01 BB01 CC07 EE02 EE07 GG02 HH03 JJ02 JJ17 JJ21 KK01 MM01 MM10 MM14 NN02 PP04

Claims (16)

[Claims] 1. A substrate through which excitation light and fluorescence are transmitted, and a polycyclic aromatic or heterocyclic aromatic provided on the substrate and exhibiting a decrease in fluorescence intensity according to oxygen concentration under the excitation light. The fluorescent substance is uniformly dispersed and fixed in the porous filter, and a fluorescent generating layer, which is provided on the fluorescent generating layer, reflects the fluorescence emitted from the fluorescent generating layer, blocks external light,
A coating layer that transmits oxygen and protects the fluorescence generating layer,
An element for oxygen measurement, comprising: 2. The coating layer according to claim 1, wherein the coating layer reflects fluorescence emitted from the fluorescence generation layer and transmits oxygen, a fluorescence reflection layer that blocks external light and transmits oxygen.
The element for oxygen measurement according to claim 1, further comprising a protective layer permeable to oxygen. 3. The coating layer includes a fluorescence reflection / external light blocking layer that reflects fluorescence emitted from the fluorescence generating layer, blocks external light, and transmits oxygen, and a protective layer that transmits oxygen. The element for oxygen measurement according to claim 1, wherein: 4. The element according to claim 1, wherein the filter is formed of an oxygen-permeable compound. 5. The filter according to claim 1, wherein the filter is formed of a fluorine compound or a silicon compound.
The element for measuring oxygen according to claim 1. 6. The coating layer, the protective layer, the fluorescence reflection / external light blocking layer, the fluorescence reflection layer, or the external light blocking layer is formed of an oxygen-permeable fluorine-based compound or a silicon-based compound. The oxygen measuring element according to claim 1, wherein 7. The method according to claim 1, wherein the substrate is quartz glass, heat-resistant glass,
The element for oxygen measurement according to any one of claims 1 to 6, wherein the element is made of sapphire glass. 8. The coating layer, the fluorescence reflection / external light blocking layer, the fluorescence reflection layer, or the external light blocking layer is selected from the group consisting of carbon, iron oxide, titanium and a compound thereof, and a mixture thereof. The oxygen measuring element according to claim 1, comprising a powder of a selected material. 9. A process for purifying a polycyclic aromatic or heteroaromatic fluorescent substance powder exhibiting a decrease in fluorescence intensity in accordance with oxygen concentration under excitation light, and purifying the processed and purified fluorescent substance. A dispersion in which the powder is dispersed in an oxygen-permeable liquid polymer is applied to a porous filter, penetrated, and a fluorescent substance is fixed in the filter to form a fluorescent generating layer. A method for manufacturing an element for oxygen measurement, comprising: fixing the device on the upper surface; and forming a coating layer or a fluorescence reflection / external light blocking layer thereon. 10. A polycyclic aromatic or heteroaromatic fluorescent substance powder exhibiting a decrease in fluorescence intensity in accordance with oxygen concentration under excitation light is treated and purified. A dispersion in which the powder is dispersed in an oxygen-permeable liquid polymer is applied to a porous filter, penetrated, and a fluorescent substance is fixed in the filter to form a fluorescent generating layer. A method for manufacturing an element for oxygen measurement, comprising fixing a fluorescent reflection layer and an external light blocking layer in this order on an upper surface. 11. The oxygen according to claim 9, wherein the treatment and purification of the fluorescent substance are performed using a solution of aniline, perchloric acid, acetone, ethanol, hydrogen sulfide, sulfuric acid, or a sulfur compound. Manufacturing method of measuring element. 12. The oxygen-permeable silicon-based compound and / or fluorine-based compound in which the coating layer is formed by dispersing a powder of a material selected from the group consisting of carbon, iron oxide, titanium and a compound thereof, and a mixture thereof. The method for producing an element for oxygen measurement according to claim 9, wherein the solution of (1) is applied to a fluorine-based compound filter or a silicon-based compound filter and then fixed. 13. The fluorescence reflection / external light blocking layer, or
Each of the fluorescent reflection layer and the external light blocking layer, an oxygen-permeable silicon-based compound in which powder of a material selected from the group consisting of carbon, iron oxide, titanium and a compound thereof, and a mixture thereof, and The method for producing an oxygen measuring element according to claim 9, wherein the method is formed by applying a solution of a fluorine-based compound and then fixing the solution. 14. A light source that emits excitation light, a substrate that transmits the excitation light from the light source, and a substrate provided on the substrate.
Under the excitation light, a polycyclic aromatic or heterocyclic aromatic fluorescent substance exhibiting a decrease in fluorescence intensity in accordance with the oxygen concentration is uniformly dispersed and fixed in the porous filter, and a fluorescence generating layer,
A coating layer that is provided on the fluorescence generating layer, reflects fluorescence emitted from the fluorescence generation layer, blocks external light, transmits oxygen, and protects the fluorescence generation layer, or is emitted from the fluorescence generation layer. An oxygen measurement element comprising a fluorescence reflection / external light blocking layer that reflects external fluorescent light, blocks external light, and transmits oxygen, and fluorescent light that receives the fluorescent light emitted from the fluorescent light generating layer via the substrate. An oxygen sensor, comprising: a detection unit; and a signal processing unit that processes an output signal from the fluorescence detection unit and outputs a signal indicating an oxygen concentration. 15. The oxygen sensor according to claim 14, wherein the light source includes an LED that emits blue light and ultraviolet light for excitation. 16. A band-pass filter having a pass band centered on the wavelength of the excitation light of the fluorescent substance, a photodiode for receiving the excitation light transmitted through the band-pass filter, and receiving an output of the photodiode. 15. The oxygen sensor according to claim 14, further comprising: a light source driving amplifier for maintaining a constant excitation light intensity.