JP2002162354A - Optical sensor of oxygen and pressure having for very fast responding function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pressure-sensitive coating with high levels of function which has a high sensitivity of oxygen to rapidly respond and not to be affected by a temperature variation, and allow easily forming an oxygen sensing film. SOLUTION: A sensor having functions for sensing oxygen and pressure, has a self-organizing function on a surface of a substrate and comprises a thin film formed from a luminous coloring matter by an excited light. The coloring matter having the functions for sensing oxygen and pressure, which has the self-organizing function, has a carboxyl group or a sulfone group. The substrate uses a metal oxide film, e.g. an aluminum oxide, a titanium oxide, an iron oxide, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical oxygen sensor using an oxygen-sensitive dye, and more particularly to an optical oxygen sensor having high stability and excellent high-speed response.

[0002]

2. Description of the Related Art Conventionally, an oxygen-sensitive paint known as an oxygen sensor has been obtained by dissolving a photoexcitable substance having an oxygen quenching property in an oxygen-permeable resin such as vinyl chloride and polystyrene. This paint is applied to a base material to form an oxygen sensor, but in a sensor using this paint, the contact between the photoexcitable substance and oxygen depends on the diffusion phenomenon of oxygen in the resin, so the oxygen sensitivity depends on the temperature. And poor time response to pressure fluctuations. Also, at low temperatures, the oxygen permeability of the resin decreases, resulting in extremely low sensitivity, detection of trace amounts of oxygen in the upper atmosphere, measurement of minute pressure on the surface of the object, and pressure distribution on the surface of the specimen in the low-temperature wind tunnel. It could not be used for measurement.

[0003] For this reason, the present inventor formed a porous film on the surface of a sensor base material in order to directly contact oxygen with the photoexcited substance instead of dispersing the photoexcited substance in the resin. Proposed a method of directly adsorbing and holding a photoexcited substance on a substrate, and a sensor prepared by using this method (Japanese Patent No. 31131).
01671). The sensor by this method has high sensitivity and is extremely excellent with little decrease in sensitivity at low temperature, but the sensor base material suitable for forming the porous film is limited, and the photoexcitation of the porous film is limited. There still remains a problem that the operation of adsorbing a substance is not easy in any specimen.

[0004]

SUMMARY OF THE INVENTION The present invention provides a high-performance pressure-sensitive paint which can form an oxygen-sensitive film easily while having a fast time response and a high oxygen sensitivity which is not affected by temperature changes. It is to try.

[0005]

An optical oxygen and pressure sensor according to the present invention has a self-organizing function on a substrate surface.
In addition, it is characterized by comprising a thin film formed of oxygen and a dye having a pressure-sensitive function. The oxygen-sensitive dye having a self-organizing function and the dye having a pressure-sensitive function emit light by excitation light and have a carboxyl group or a sulfone group in a molecule, and the substrate is a metal oxide layer. Features, aluminum oxide, titanium oxide,
Iron oxide or the like is used.

[0006]

More specifically, an example in which tetrakis (4-carboxyphenyl) porphyrin (TCPP) is used as a dye for forming the self-organizing film and aluminum oxide is used as an object substrate will be described. By immersing an aluminum substrate having an oxide layer on the surface as a sample substrate in an ethanol or methanol solution in which the TCPP is dissolved, a self-assembled film is formed on the surface. When the solution concentration is 10 ⁻³ mol / l, the formation is completed in about 10 seconds of immersion. The substrate on which TCPP has formed a self-assembled film on its surface is washed with alcohol,
Oxygen and pressure sensors can be made by cleaning with an ultrasonic cleaner.

FIG. 1 is a schematic view showing the structure of the sensor thus produced. As shown, the carboxyl group binds to the surface of the metal oxide, and a self-assembled film having an oxygen-sensitive dye arranged on the surface of the film is formed on the surface of the substrate. In this way, a self-assembled thin film in which the oxygen-sensitive dye is densely arranged on the surface is formed on the substrate, so that a sensor that strongly binds to the substrate and has high stability can be produced extremely easily. In addition, since the oxygen-sensitive dyes densely arranged on the surface come into direct contact with oxygen gas, high-speed response can be obtained. Since the film is self-assembled, it is characterized in that it is uniformly formed on a complicated substrate surface.

The measurement results of the response speed are shown below. The pressure chamber in which the above-mentioned sensor was disposed was adjusted to 1 kPa by a reference pressure generator, and in that state, the solenoid valve was opened to open to atmospheric pressure, thereby creating a stepwise pressure change. The pressure chamber is as small as about 1.5 CC. In addition, by applying a high voltage of about 160 V to the solenoid valve, the pressure in the chamber (P-Pmin) / (Pmax-Pmi
n) The change from 10% to 90% was caused in a short time of 0.639 msec.

A xenon lamp was used as the excitation light source for measurement, and the light emission of the sensor corresponding to the pressure change was detected by a photomultiplier tube and output as a voltage value to an oscilloscope via a frequency filter. 340 to 44 for excitation light
An interference filter of 0 nm was used, and an interference filter suitable for the dye was used for light emission detection of the sensor. A Peltier device was used to control the temperature of the sensor substrate in order to observe changes in the light emission state due to temperature. The substrate temperature was monitored by a thermocouple attached to the holder near the sensor. Further, a silicon diaphragm type electronic pressure sensor having a resonance frequency up to 500 kHz was used as a pressure transducer serving as a reference for comparison.

FIG. 2 shows the measurement results when the temperature of the TCPP film is 20 ° C., together with the measurement results of the electronic pressure sensor.
In addition, the measurement was also performed at a TCPP film temperature of 30 ° C., 40 ° C., and 50 ° C., but the measurement results overlapped with the measurement results of the case of 20 ° C., and no change due to the temperature was observed. Thus, it can be seen that the measurement result of the TCPP film almost coincides with the measurement value of the electronic pressure sensor irrespective of the temperature, and that the pressure fluctuation of about 3 ms period is faithfully detected.

[0011]

As described above, the optical oxygen and pressure sensor having an ultra-high-speed response function of the present invention uses an oxygen-sensitive dye which forms a self-assembled film on a substrate.
A stable optical oxygen and pressure sensor could easily be made, and the sensor could obtain an unprecedented sensor with a high-speed response comparable to an electronic pressure sensor.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the structure of an optical oxygen and pressure sensor having a high-speed response function according to the present invention.

FIG. 2 is a graph showing a result of a pressure / temperature sensitivity test showing a high-speed response function of the optical oxygen and pressure sensor of the present invention.

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Claims (3)

[Claims] 1. An optical oxygen and pressure sensor having an ultra-fast response function, comprising a thin film formed on a substrate surface with a dye having a self-organizing function and an oxygen-sensitive function. 2. The dye according to claim 1, wherein the dye having an oxygen-sensitive function and the pressure-sensitive function having a self-organizing function emits light by excitation light and has a carboxyl group or a sulfone group in a molecule. Oxygen and pressure sensor with ultra-fast response function 3. The optical oxygen and pressure sensor having an ultra-fast response function according to claim 1, wherein said substrate is a metal oxide layer.