JPH0727731A - Odor sensor and odor sensor unit - Google Patents

Abstract

PURPOSE:To provide an odor sensor which can be used without a complicate measuring system and is more superior in stability of sensing properties than a prior art. CONSTITUTION:A comb-like electrode 13 of a gold thick film is formed on an alumina ceramics substrate 11. An application liquid is prepared by dissolving, e.g. 1g dioctylphosphate as a sensing agent, 10g vinyl chloride as a supporting polymer, 20g dioctylphthalate as a plasticizer in 100g tetrahydrofuran as a solvent. The substrate 11 with the electrode 13 is dipped in the application liquid. The application liquid is dried after the substrate 11 is pulled out to obtain a sensitive film. The electrode may be built in the sensitive film without using a substrate. The sensitive film may be a laminate of a plurality of individual sensitive films of different sensitivities. If the sensitive film is a laminate- type, an upper and a lower electrodes may be formed on the upper and lower surfaces of the film. Moreover, an intermediate electrode may be provided between the sensitive films of the laminate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an odor sensor and an odor sensor unit suitable for use in, for example, a disaster prevention system, air environment measurement, food industry, process control, medical treatment, and health use. Is.

[0002]

2. Description of the Related Art The chemical sensation represented by the olfactory sense has a very high discriminating ability and sensitivity, and if it can be artificially realized, its field of application will be wide and its industrial utility will be high. Very expensive.

For example, in the field of disaster prevention systems, efforts have been made in the past for early detection of fires by combining various physical quantity sensors. That is, a plurality of sensors such as a gas sensor that detects an odorless inorganic gas such as CO and NO _x generated by a fire, a smoke sensor that detects smoke, an optical sensor that detects a flame, and a heat sensor that detects an increase in ambient temperature. An attempt has been made to construct a disaster prevention system that can detect the occurrence of fire without malfunction by making a comprehensive judgment by combining the above. On the other hand, in the early stages of a fire, especially in a smoldering state (still smoldering), a large amount of odorous gas is generated. Therefore, if the odor sensor for detecting these odor substances can be incorporated into the disaster prevention system together with the smoke, temperature, and inorganic gas sensors, the reliability of the disaster prevention system can be further improved.

As a conventional sensor that can be used as such an odor sensor or a method that is likely to be a hint for constructing it, there are, for example, the following sensors or methods (a) to (d).

(A) An odor sensor using an oxide semiconductor (for example, Japanese Patent Laid-Open No. 54-114296).

(B) An odor sensor equipped with a detecting portion in which an alkaline earth metal is carried on a tin oxide semiconductor (for example, Japanese Patent Laid-Open No. 1-259250).

(C): Using liquid crystal :: Ionizing air at high voltage to see changes in ionic current,
: Using an organic semiconductor such as β-carotene :: Measuring the membrane potential of dog olfactory cells: Recording human brain waves: Combined bilayer membrane and crystal oscillator: Plant For measuring the membrane potential of mesophyll cells,
: A combination of a thermistor and a film (to each of them, the prior art of JP-A-1-259250).

(D): A method for electrochemically detecting a change in membrane potential or membrane resistance of this bilayer membrane in an aqueous NaCl solution when a bitter or odorous substance is adsorbed on the bilayer membrane,
: A method for detecting a change in the frequency of a crystal resonator when an odor substance is adsorbed on a bilayer film cast on the crystal resonator (for example, JP-A-63-222248).

Among the above-exemplified sensors and methods, the one using an oxide semiconductor has a track record as an inorganic gas sensor such as CO or NO _x . However, of the above-exemplified sensors and methods, those using organic substances, for example, (c)
It is considered that some of them and those using a bilayer film as in (d) can be expected as sensors for odorous substances rather than those using an oxide semiconductor. Since odorants are mainly organic substances, and in general, similar organic substances have high affinity, it is considered that organic substances are suitable for odorants of organic substances, so organic substances were used. This is because it is considered that the sensor can be expected to have better sensitivity characteristics.

[0010]

However, the conventional sensors and methods using organic substances (for example, those in the above items (c) and (d)) are all complicated measurement for odor measurement. There are problems that the system cannot be manufactured at low cost because a device is required and that the characteristic of the sensitive film that senses the odor in the odor sensor is significantly deteriorated.

As a concrete example, in the method (d),
It is necessary to immerse the sensor in an aqueous solution of salt, it is necessary to blow air containing odorant into the aqueous solution of salt to dissolve the odorant in this aqueous solution, and an aqueous solution of salt is required. A complicated measurement system is required, such as the need for a counter electrode and a reference electrode. Further, the method (d) requires an expensive and highly accurate device for measuring the change in the frequency of the crystal unit. In addition, olfactory cells, bilayer membranes, mesophyll cells of plants, etc. are rapidly deteriorated.

This application has been made in view of the above-mentioned circumstances. Therefore, an object of the first invention of this application is to provide a novel odor sensor in which the structure of the sensor and the measurement system can be simplified compared with the conventional ones. is there. Another object of the second invention of the present application is to provide a sensor structure useful for various odor sensors using an organic thin film as an odor sensitive film. Another object of the third invention of this application is to provide a sensor unit useful for improving the sensing ability of various odor sensors (not limited to those using an organic thin film as a sensitive film).

[0013]

In order to achieve the object of the first invention, the inventor of the present application has completed the first invention based on the following findings.

Reference I (Fire and Materials (Fire
And Materials), vol. 10, pp. 21-
28 (1986), particularly page 25, Table 3. Has
It is disclosed that various organic gases are generated in the early stage of a wood fire. In detail, as an odor component, aldehydes (for example, acetaldehyde, benzaldehyde,
It is disclosed that a large amount of acrolein, etc.) and cyclopentadiene are generated, and a large amount of methane, ethylene, and propene are generated as odorless gas components.

On the other hand, the inventor of the present application continued diligent research in order to achieve the object of the first invention. As a result, a certain kind of organic substance (organic sensitizer) was fixed by a supporting polymer. It has been found that the electrical characteristics of the formed organic thin film change when the organic gas as the odor component as described above acts on it. And, I noticed that such a change in the electrical characteristics can be easily measured by providing an electrode in contact with the organic thin film by using this electrode and a simple measuring device, and furthermore, the odor can be sensed by the change in the electrical characteristic. .

Therefore, according to the odor sensor of the first invention of the present application, a sensitive film containing an organic sensitizer and a supporting polymer, the electrical properties of which change in response to an odor, and the electrical properties of the sensitive film are measured. It is characterized by including an electrode of. Incidentally, the electrical characteristics in the first invention and the second invention, the electrical conductivity represented by an electrical resistance value or a current value,
Alternatively, it may be a capacitance value, or impedance in the case of alternating current (including cases of multiple types of characteristics).

In carrying out the first aspect of the present invention, the sensitizer is not particularly limited and may be various ones that meet the purpose of the first aspect of the invention. For example, dioctyl phosphate, cholesterol, trioctylammonium chloride, oleylamine and triolein have been identified as potential sensitizers. Further, the supporting polymer is not particularly limited and may be various ones that meet the object of the present invention. For example, polyvinyl chloride, polyester,
Acrylic resin or the like can be used as the supporting polymer. Since polyvinyl chloride easily mixes with the plasticizer, it is suitable as a supporting polymer particularly when the plasticizer is used.

Further, in carrying out the first aspect of the present invention, it is preferable that the sensitive film contains a plasticizer. This is because the use of the plasticizer dissolves the odorous substance in the plasticizer and improves the odor-sensitive characteristics of the sensitive film. In addition,
The plasticizer is not particularly limited and may be various ones that meet the object of the first invention. For example, dioctyl phthalate can be mentioned.

Further, the second invention of this application has been made with respect to a specific structure of various odor sensors using an organic thin film as a sensitive film, including the odor sensor of the first invention.

That is, the second invention of this application is an odor sensor comprising a sensitive film composed of an organic thin film whose electrical characteristics change in response to an odor, and electrodes for measuring the electrical characteristics of the sensitive film. Each of the following configurations (a) to (e) is characterized.

(A). A configuration in which the first pole portion and the second pole portion of the electrode are provided side by side on a common insulating substrate, and the sensitive film is provided on the first pole portion and the second pole portion over both pole portions.

(B). A structure in which the electrodes are embedded in a sensitive film, and both surfaces of the sensitive film are in contact with the measurement atmosphere.

(C). A configuration in which a first pole portion and a second pole portion of the electrode are provided so as to face each other with the sensitive film interposed therebetween. In this configuration, it is preferable that at least one of the first pole portion and the second pole portion has gas permeability. This makes it easier for the gas in the measurement target atmosphere to come into contact with the sensitive film. Here, the electrode having gas permeability may have various configurations as long as it is permeable to the gas in the measurement atmosphere. For example, when the electrode is composed of a film, it is formed so that the film itself is in a porous state, or in the first place, the electrode itself is actively patterned in a comb shape or a mesh shape, or a large number of pores are formed in the electrode. Means such as patterning the electrode to form

(D). A configuration in which the sensitive film is composed of a laminated body of a plurality of (any number of two or more) individual sensitive films having different sensitivities. In this configuration, it is preferable that at least one of the first pole portion and the second pole portion has gas permeability. The reason is the same as the above item (c). Here, the electrode having gas permeability is the above (c).
It can be the one described in section.

(E). The sensitive membrane comprises a plurality of (any number of two or more) individual sensitive membranes showing different sensitivities,
The electrodes include a lower electrode, an intermediate electrode, and an upper electrode, and the plurality of individual sensitive films are sequentially laminated with the intermediate electrode interposed, and the lower electrode is provided on the lower surface of the lowermost individual sensitive film. And the upper electrode is provided on the upper surface of the uppermost individual sensitive film. In this configuration, at least one of the upper electrode and the lower electrode preferably has gas permeability. The reason is the same as the above item (c). Here, the electrode having gas permeability can be the one described in the above item (c). Further, in this structure, it is preferable that each individual sensitive film is shaped so as to expose a part of the other individual sensitive film immediately below it.

Further, the third invention of this application favorably uses various odor sensors including the odor sensor of the first invention (any of which does not have a sensitive film made of an organic thin film). It is intended to provide a possible sensor unit. That is, the following (I) to (IV)
Each of the configurations shown in is characterized.

(I). A configuration comprising an odor sensor, a container for housing the odor sensor, and ventilation holes provided in a wall portion on the upper end side and a wall portion on the lower end side of the container.

(II). In addition to the configuration of (I) above, a configuration is further provided which is provided in the container and includes heating means for increasing the atmospheric temperature in the container in order to promote the movement of the gas of the measurement target atmosphere in the container.

(III). A configuration comprising an odor sensor and a net provided at a position that is upstream of the flow of the gas to be measured with respect to the odor sensor.

(IV). A configuration in which the odor sensor unit according to (I) or (II) is provided with the net according to (III).

[0031]

According to the constitution of the first invention of this application, when the atmosphere containing the odor substance touches the sensitive film, the odor substance diffuses into the sensitive film and the electric characteristics of the sensitive film are changed. This change in the electrical characteristics can be taken out by the electrodes provided in the sensor, so that the odor can be detected. Also,
Since an organic sensitizer is used, it is considered that the sensitivities to odorous substances composed of organic substances are higher than those when it is not. Therefore, it is possible to detect the odor concentration in the order of ppm. Further, the specificity for the odorant can be controlled by selecting the sensitizer.

Further, according to the second invention of this application, there is provided an odor sensor comprising a sensitive film composed of an organic thin film whose electrical characteristics change in response to an odor, and an electrode for measuring the electrical characteristics of the sensitive film. Various types of odor sensors are available, depending on the application and desired characteristics. Specifically, with the configuration described in (a) above, a sensor having one surface as an odor detection surface can be obtained. In the configuration described in (b) above, that is, in the configuration in which the electrodes are embedded in the sensitive film and both sides of the sensitive film are in contact with the measurement atmosphere, the area in contact with the measurement target gas can be made wider than in the case where it is not. , Improvement in sensitivity can be expected.
In the configuration of (c) above, the distance between the sensitive films interposed between the first pole portion and the second pole portion of the electrode is about the film thickness of the sensitive film, so the resistance value between the electrodes is, for example, from the configuration of (a) above. Since it can be made small, changes in electrical characteristics can be measured with an electronic circuit such as a normal tester. Further, the sensitivity can be improved. The structure described in the above (d), that is, the first and second pole portions of the electrode are provided so as to face each other with the sensitive film sandwiched therebetween, and the sensitive film is a laminated body of a plurality of individual sensitive films having different sensitivities. In the configuration,
Since the individual sensitive film acts as a filter of the individual sensitive film below it, the selectivity of the lower individual sensitive film to the odor substance to which it is specifically sensitive is increased. In the configuration of (e) above, that is, the configuration in which the upper, middle (a plurality of) and lower electrodes are provided and the individual sensitive films are provided between the electrodes, the electrode pairs whose electrical characteristics are measured can be arbitrarily set as necessary. A plurality of sets can be selected to monitor changes in the electrical characteristics of the sensitive film, so that a large amount of information regarding odor can be obtained. Further, in the configuration of (e), when each individual sensitive film has a shape that exposes a part of another individual sensitive film immediately below it, information unique to each individual sensitive film is also obtained.

Further, in each of the configurations (I) to (IV) of the third invention, the following action is obtained.

First, in the configuration of (I), the flow of gas between the inside and the outside of the container of the sensor unit is promoted, and odor sensing is facilitated. In the configuration (II), the flow of gas between the inside and outside of the container is further promoted and the odor sensing is easier than in the configuration (I) in which the heating means is provided. In the configuration of (III), a substance that interferes with the sensing of the odor in the measurement atmosphere, such as smoke particles, is trapped by the net. (I
In the constitution of V), both the actions (I) and (II) and the action (III) can be obtained.

[0035]

Embodiments of the odor sensor of the first and second inventions and an odor sensor unit of the third invention of the present application will be described below with reference to the drawings. It should be noted that the drawings used in the description merely schematically show the dimensions, shapes, and arrangement relationships of the respective constituent components to the extent that these inventions can be understood. Further, in each drawing, the same components are denoted by the same reference numerals, and duplicate description thereof will be omitted in some cases. Also, the materials described in the examples below,
Numerical values indicating film forming conditions, film thickness, size, etc. are merely examples within the scope of the present invention.

1. Description of first invention and second invention 1-1. Description of First Embodiment of First Invention and Second Invention FIG. 1 is a plan view showing the odor sensor 10 of the first embodiment of the first invention and the second invention as seen from above the sensitive film 15 and this plane. It is sectional drawing in the II line of a figure.

The odor sensor 10 of the first embodiment has an insulating substrate 11 and electrodes (electrode pairs) 13 provided on the insulating substrate 11 and composed of a first pole portion 13a and a second pole portion 13b. On the electrode 13,
And a sensitive film 15 provided so as to extend between 13b.

Here, the substrate 11 has a vertical dimension of about 20.
mm, a lateral dimension of about 10 mm, and a thickness of about 1 mm are used for the alumina ceramic plate. Further, as the electrode 13, a comb-shaped electrode 13 composed of a first pole portion 13a and a second pole portion 13b is used. In this case, the comb-shaped electrode 13 has a comb tooth width of 200 μm and a distance between the teeth of 200 μm.
m. The comb-shaped electrode 13 is composed of a gold thick film electrode formed by a screen printing method.
The sensitive film 15 is an organic thin film whose electric characteristics change in response to an odor, and is composed of an organic thin film containing a sensitizer and a supporting polymer. In this embodiment, the organic thin film (sensitive film) is the insulating substrate 11 on which the electrodes 13 have been formed.
It is formed by applying a coating solution for forming a sensitive film (described later) on the above by a dipping method and drying this. In this example, as a coating liquid for forming a sensitive film, 6 shown in Table 1 below is used.
The coating liquids for forming the sensitive film of the examples are used, and for comparison, one type of the coating liquid for forming the sensitive film (only the supporting polymer and the solvent) is used for comparison. The sample of N0.6 in Table 1 described later has a sensitizer content of 0, but the dioctyl phthalate used as the plasticizer is considered to be a sensitizer depending on the viewpoint, so it is included in the examples. Explaining. Each of the sensitizers used was manufactured by Tokyo Kasei Co., Ltd., and the vinyl chloride used as the supporting polymer was referred to as a high molecular weight product manufactured by Sigma. In addition, as for the compounding ratio of each material in Table 1 below, the usage fee (gram number) of each material is described as it is.

Using each of these sensitive film-forming coating solutions, six types of odor sensors of Examples and one type of odor sensor of Comparative Example are produced as described above. In any of the odor sensors, the thickness of the sensitive film 15 is about 20 μm in terms of the dry film thickness of the coating solution for forming the sensitive film.

The odor sensor 10 of the first embodiment and the odor sensor of the comparative example thus produced are evaluated as described below. The measuring system used was as follows. 2A and 2B are explanatory views of the system. However, FIG. 2B shows an example of a second embodiment described later. Of course, these systems are just examples.

In this case, a glass chamber 21 having a volume of 10 liters is used as a container for containing and evaluating the odor sensor to be evaluated (the odor sensor of the first embodiment or the comparative example). This glass chamber 21 is
A part of the wall is provided with an openable / closable window 21a for introducing an odor substance, and an agitation fan 21b is provided inside. The electrode of the odor sensor 10 is connected to the measuring device outside the chamber 21 via the lead wire 10a. In this embodiment, since the resistance value of the sensitive film 15 is monitored as the electric characteristic of the sensitive film 15, an insulation resistance meter (HP-432 manufactured by Yokogawa Hewlett-Packard Co., Ltd.) is used as the measuring device 23.
9A) is used. In addition, this glass chamber 21
Put filter paper 25 inside. The filter paper 25 is used to store various odor substances. Further, in this case, the chamber 21
An odor substance 29 is supplied to the inner filter paper 25 using a microsyringe 27.

Next, the responses of the six types of odor sensors 10 of the examples and the odor sensor of the comparative example to the four types of odor substances and the water vapor which becomes a factor that interferes with the sensing when the odor sensor is actually used. Check the response and the procedure described below. As four kinds of odor substances, here, 3
-Methyl 2-cyclopenten-1-one, 2-methylethyl acetate, benzaldehyde and triethylamine are used respectively.

It is assumed that a DC voltage of 10 V is applied between the first pole portion 13a and the second pole portion 13b of the electrode 13 of the odor sensor 10. The resistance value (initial resistance value) of the sensitive film of each of the odor sensor 10 of each example and the odor sensor of the comparative example before the odor substance is put into the chamber 21 is measured by a measuring device (insulation resistance meter) 23. The initial resistance value of each sample is shown in the column of Sensitizer in Table 2 below. Next, the odorous substance 29 is supplied into each chamber 21 so that the concentration in the chamber becomes a predetermined concentration. The resistance value of the sensitive film after 5 minutes from the time when the odor substance was supplied into the chamber is measured for each of the samples of the comparative example and each example. This process is performed for each odor substance. In addition, steam is also used. In this case, the water vapor was supplied by introducing moisture-containing air into the chamber 21 from another chamber (not shown) containing hot water of a predetermined temperature by a blower (not shown). Table 2 below shows the change in resistance value of each sample when the concentration of the odorous substance was set to 10 ppm in the chamber 21 and the change in resistance value of each sample when water vapor was supplied into the chamber 21. . In Table 2, the numerical value shows the rate of change in resistance value given by [resistance value of sensitive film 2 minutes after supplying odor substance] / [initial resistance value of sensitive film], and a minus sign is shown in this numerical value column. Indicates that the resistance value of the sensitive film has decreased due to the supply of the odor substance, and that only the numerical value indicates that the resistance value of the sensitive film has increased due to the supply of the odor substance, and the letter N indicates the resistance value. No change was observed (the same applies to Tables 3 and 4 below).

From Table 2 below, it can be seen that the comparative sample (No. 7) containing only the supporting polymer did not respond to water vapor and each odorous substance. On the other hand, it can be seen that the six types of samples of the examples show different responses depending on the type of odor substance. From this, it can be understood that the odor sensor of the first invention responds to the odor substance in a sufficiently specific manner. Also, the effect of water vapor is no. It can be seen that it is not observed except for the sample of 4 (using oleylamine as a sensitizer). From these, it can be understood that the target odor can be easily detected without using any special measuring device by using the odor sensors of the examples alone or in combination of two or more.

The shape of the electrode 13 formed on the substrate in the first embodiment is not limited to the comb-shaped electrode, but may be any shape according to the design.

1-2. Description of the second embodiment of the first invention and the second invention In the above-described first embodiment, one surface of the sensitive film 15 is in contact with the insulating substrate 11, so that the surface that can be in contact with the measurement atmosphere is the sensitive film 15. It is limited to one side of. In the odor sensor, various advantages (for example, improvement in sensitivity and response speed) can be obtained if the surface area of the sensitive film 15 that can be used for odor detection can be increased. The second embodiment is an example suitable for expanding the surface area that can be used for odor detection.
FIG. 3 (A) is a diagram used for the description, and is a plan view showing an odor sensor 30 of a second embodiment of the first invention and the second invention, and a cross-sectional view taken along line I-I of this plan view.

In the odor sensor 30 of the second embodiment, an electrode (electrode pair) 31 composed of a first pole portion 31a and a second pole portion 31b is embedded in the sensitive film 15, and the sensitive film 1
Both surfaces of No. 5 can contact the measurement atmosphere. Further, in this case, in order to secure the mechanical strength of the odor sensor 30, appropriate positions of the first pole portion 31a and the second pole portion 31b of the electrode 31 are insulated from each other by an insulating support 33.
Supported by. As the electrode 31, the first pole portion 31
The comb-shaped electrode 31 composed of a and the second pole portion 31b is used. In this case, the comb-shaped electrode 31 has a comb tooth width of 4
The distance between the teeth is 400 μm. The support 33 is made of a polymer material such as polystyrene in this case. Further, the sensitive film 15 is formed by using the coating liquid for forming various sensitive films used in the first embodiment (see Table 1 below).

In this case, the odor sensor 30 of the second embodiment was manufactured by the procedure described below. 4 to 6 are process diagrams used for the description.

First, the vertical dimension is about 30 mm and the horizontal dimension is about 1.
A predetermined resist pattern is formed (not shown) by a photolithography method on a stainless steel thin plate having a thickness of 0 mm and a thickness of about 0.1 mm, and then the stainless steel plate is selectively etched with an iron chloride-based etching solution. As a result, an electrode forming plate 31x having a portion which will be the comb-shaped electrode 31 in the future as shown in FIG. 4 is obtained. This figure shows an example of an electrode forming plate 31x capable of taking two electrodes 31. A part of the electrode forming plate 31x (a part other than the part which will be the comb-shaped electrode 31 in the future) is later removed by, for example, a press machine. This electrode forming plate 31x is shown in FIG.
In the figure, a portion 31y that will be a comb-shaped electrode in the future and a portion 31z that will be removed by a press machine (a portion that will be unnecessary in the future) 31z are shown.

The electrode forming plate 31x is dipped in a coating solution for forming a sensitive film to a predetermined position, then withdrawn from the solution, and then the sample is dried. As a result, as shown in FIG. 6, the sensitive film 15 is formed on the electrode forming plate 31x in a state of covering the main part of the portion which will be the comb-shaped electrode 31 in the future. The support 33 is formed by the electrode forming plate 31x.
May be performed before or after being dipped in the coating liquid for forming a sensitive film or before being processed by a press machine.

Electrode forming plate 31x on which the sensitive film has been formed
The unnecessary portion in is removed by a press machine (not shown). As a result, the second operation already described with reference to FIG.
The odor sensor 30 of the embodiment is obtained.

According to the above manufacturing procedure, six kinds of odor sensors of the second embodiment are manufactured using the six kinds of coating liquids for forming the sensitive film described in the first embodiment (see Table 1 below). . The thickness of the sensitive film 15 at this time is about 20 μm in terms of the dry film thickness of the coating liquid for preparing the sensitive film.

On the other hand, as a comparative example of the second embodiment, the odor sensor 10 of the first embodiment (a sensor in which only one surface of the sensitive film 15 can come into contact with the measurement atmosphere) and the shape and size of the electrode 13 are An odor sensor matched with that of the second embodiment is manufactured by the procedure described in the first embodiment. Hereinafter, the odor sensor of this comparative example is referred to as “Comparative example of the second embodiment (first example
(Corresponding to the embodiment) odor sensor 10x ". In this case as well, the coating liquid for preparing the sensitive film of the six examples (see Table 1)
Six types of odor sensors of Comparative Example (corresponding to the first embodiment) of the second embodiment are manufactured by using. FIG. 3B is a plan view and a sectional view of an odor sensor 10x of a comparative example (corresponding to the first embodiment) of the second embodiment.

Next, the odor sensor 30 of the second embodiment and the odor sensor 10 of the comparative example (corresponding to the first embodiment) of the second embodiment.
The response of each x to various odorants and the response to water vapor are examined by the same procedure as that described in the first embodiment. The results are the same as in Table 2 below for each odor sensor 20 of the second example, and in Table 4 below for each odor sensor 10x of the comparative example (corresponding to the first example). The notation is shown.

It can be seen from Tables 3 and 4 that the odor sensor of the second embodiment has the same specificity for various odor substances as the odor sensor of the first embodiment (see from the arrangement of N letters). Clear.). However, it can be seen that the odor sensor of the second embodiment generally has a larger resistance change rate than the odor sensor of the comparative example (corresponding to the first embodiment) of the second embodiment. From this, it can be said that the second embodiment has higher sensitivity than the first embodiment. Next, in order to compare the response speeds of the odor sensor 30 of the second embodiment and the odor sensors 10x of the comparative example (corresponding to the first embodiment) of the second embodiment with respect to the odor substance, here, in the second embodiment, Of the odor sensors of Examples and Comparative Examples (corresponding to the first example), those using trioctyl ammonium chloride as a sensitizer, those using oleylamine as a sensitizer, and those using benzaldehyde as a sensitizer, respectively. The response speed of benzaldehyde to benzaldehyde is investigated as follows.

The resistance value of the sensitive film of each odor sensor before supplying benzaldehyde is set to 0. Then, the concentration of benzaldehyde in the chamber 21 of FIG.
To be supplied. The resistance change amount when the resistance value of the sensitive film becomes almost constant after supplying benzaldehyde (here, 10 minutes after the odorant is supplied) is 100.
Then, the amount of change in resistance of the sensitive film after 1 minute and 5 minutes after supplying benzaldehyde is standardized. The results are shown in Table 5 below. From Table 5, the resistance change amount of the odor sensor of the second embodiment approaches 100 faster than that of the odor sensor of the comparative example (corresponding to the first embodiment) of the second embodiment (from 2 times to 1.5). It's twice as fast). From this, it can be seen that the odor sensor of the second embodiment has a faster response speed than the odor sensor of the comparative example (corresponding to the first embodiment) of the second embodiment. It is considered that this is because the sensor of the second embodiment has both sides of the sensitive film as the odor detection surface.

After performing the response speed experiment, fresh air is sent into the chamber 21. Then, the response speed when the odor substance is desorbed from the sensitive film of the odor sensor is measured by monitoring the resistance change amount of the sensitive film of each odor sensor. At this time, the resistance value of the sensitive film when sending fresh air into the chamber is 100,
When the resistance value returns to the original value and becomes almost constant (in this case, 20 minutes have passed since the air was sent into the chamber), the value was set to 0, and 5 minutes after the air was sent into the chamber, 10 After each minute, the amount of resistance change is standardized. The results are shown in Table 6 below. From Table 6, the resistance value of the odor sensor of the second embodiment returns to 0 faster than that of the odor sensor of the comparative example (corresponding to the first embodiment) of the second embodiment (2 to 1.5 times). It's early. From this, it can be seen that the odor sensor of the second embodiment has a faster regeneration speed of the sensitive film than the odor sensor of the comparative example (corresponding to the first embodiment) of the second embodiment.

Further, instead of the comb-shaped electrode 31, FIG.
The spiral first pole portion 35a and the second pole portion 3 as shown in FIG.
The sensitive electrode 15 is made up of a spiral electrode (electrode pair) 35 composed of 5b.
An odor sensor according to another aspect of the second embodiment was manufactured by embedding the odor sensor in the device, and its characteristics were measured. Also in this case, it was found that a sensor in which both sides of the sensitive film can be used as an odor detection surface, and an odor sensor having a good response speed and good reproduction speed can be obtained. In FIG. 7A, 37 is a connection terminal. Also in the odor sensor using the spiral electrode 35, the electrode plate 35x (see FIG. 7B) in which the first electrode portion 35a and the second electrode portion 35b are initially integrated is applied for forming a sensitive film. The first pole portion 35a and the second pole portion 3 are formed by immersing in a liquid, pulling it up, and then drying, and then punching out the central portion (punching area P) of the electrode plate 35x with a press machine.
It is better to form 5b.

In the second embodiment, the shape of the electrode embedded in the sensitive film is not limited to the comb shape or the spiral shape, but may be any shape. Further, the sensitive film may be formed by sequentially laminating a plurality of individual sensitive films having different sensitivities (an example in which the idea of the fourth embodiment described later is applied to the second embodiment).

1-3. Description of a third embodiment of the first invention and the second invention Next, as a third embodiment, the sensitive film is sandwiched between the first pole portion and the second pole portion 13 of the electrode for measuring the electrical characteristics of the sensitive membrane. An example in which they are provided facing each other in a state will be described. FIG. 8 is a diagram provided for the explanation. A plan view showing the odor sensor 40 of the third embodiment as seen from above the sensitive film 15 and I of this plan view.
It is sectional drawing in the -I line.

The odor sensor 40 of the third embodiment has a solid electrode made of a thick gold film as the first pole portion 41a of the electrode 41 on the insulative substrate 11, and this is arranged on the first pole portion 41a. A sensitive film 15 is provided so as to cover, and a comb-teeth-shaped electrode made of a vapor-deposited film of aluminum is provided on the sensitive film 15 as the second pole portion 41b of the electrode 41. By making the second pole portion 41b comb-shaped, the sensitive film 15 can be brought into contact with the measurement atmosphere, so that the contact of the odor substance with the sensitive film can be secured. As the substrate 11, in this case, the vertical dimension is about 40.
mm, a lateral dimension of about 20 mm, and a thickness of about 1 mm are used for the alumina ceramic plate. The first pole portion 41a is formed by using the screen printing method. Sensitive membrane 15
Is formed by the same coating method as described in the first embodiment. However, the coating solution for forming the sensitive film is 1 gram of triolein (manufactured by Tokyo Kasei) as a sensitizer, 10 grams of vinyl chloride resin (manufactured by Sigma) as a supporting polymer, and dioctyl phthalate (manufactured by Tokyo Kasei) as a plasticizer.
And 20 g of tetrahydrofuran and 100 g of tetrahydrofuran (manufactured by Tokyo Kasei) as a solvent are used. The thickness of the sensitive film 15 is 20 μm in terms of the film thickness after drying. The second pole portion 41b, which is a comb-teeth-shaped electrode, is formed by a vacuum evaporation method using a stainless-steel evaporation mask having a comb-teeth-shaped opening at the time of evaporation and has a comb-teeth width of 500 μm. And the distance between the teeth is 500 μm
It is supposed to be.

On the other hand, as a comparative example of the third embodiment, the odor sensor 10 of the first embodiment described with reference to FIG. 1 (the first pole portion 13a and the second pole portion 13b are arranged side by side on the substrate 11). Some are manufactured according to the procedure of the first embodiment. However, the coating liquid for forming the sensitive film had the composition used in the third embodiment, that is, 1 gram of triolein (manufactured by Tokyo Kasei) as the sensitizer and 10 g of vinyl chloride resin (manufactured by Sigma) as the supporting polymer. Gram, 20 grams of dioctyl phthalate (manufactured by Tokyo Kasei) as a plasticizer, and 100 grams of tetrahydrofuran (manufactured by Tokyo Kasei) as a solvent are used. Hereinafter, the odor sensor of this comparative example will be referred to as the “odor sensor of the comparative example of the third embodiment (corresponding to the first embodiment)”.

Next, the odor sensor 40 of the third embodiment and the odor sensor of the comparative example (corresponding to the first embodiment) of the third embodiment are evaluated as follows.

First, the odor sensor 40 of the third embodiment and the odor sensor of the comparative example (corresponding to the first embodiment) of the third embodiment when the chamber 21 of FIG. 2 is filled with fresh air filtered by activated carbon. The resistance value of the sensitive film is measured for each. The resistance value of the odor sensor of the comparative example (corresponding to the first embodiment) of the third embodiment was 4 × 10 ⁸ Ω. On the other hand, the resistance value of the odor sensor of the third embodiment was 1 × 10 ⁶ Ω, and it could be measured sufficiently in the DC resistance measuring mode of the tester. In the odor sensor 40 of the third embodiment, since the first pole portion 41a and the second pole portion 41b of the electrode 41 face each other by the thickness of the sensitive film 15 (about 20 μm in this example), the resistance of the sensitive film is reduced. The value is reduced.

Next, the resistance value of the sensitive film of each odor sensor is measured when the chamber 21 of FIG. 2 is set to a 10 ppm concentration atmosphere of benzaldehyde as an odor substance. When this resistance value is converted into a change rate when the resistance value when the chamber is fresh air is set to 1, it is 0.2 in the case of the odor sensor of the third embodiment. Therefore, a comparative example of the third embodiment (corresponding to the first embodiment)
In case of the odor sensor, the resistance change rate is 0.5,
It was found that the example was 2.5 times more sensitive.

1-4. Description of Fourth Embodiment of First and Second Inventions Next, as a fourth embodiment, an example in which the sensitive film is composed of a laminate of a plurality of individual sensitive films having different sensitivities will be described. FIG. 9 is a diagram for explaining one of the modes. It is the top view which showed the odor sensor 50a of the 1st aspect of 4th Example seen from the sensitive film | membrane 15x, and the sectional view in the II line of this top view.

The odor sensor 50a according to the first aspect of the fourth embodiment has the same structure as that of the third embodiment except that the electrode 4 is formed on the insulating substrate 11.
1 has a solid electrode made of a thick gold film as the first pole portion 41a, and a laminated body 1 of the first individual sensitive film 15a and the second individual sensitive film 15b so as to cover the first pole portion 41a.
5x, and a comb-shaped electrode made of a vapor-deposited film of aluminum is provided on the sensitive film 15x as the second pole portion 41b of the electrode 41 as in the third embodiment. By forming the second pole portion 41b in a comb shape, the sensitive film 15x can be brought into contact with the measurement atmosphere, so that the contact of the odor substance with the sensitive film can be ensured. In this case, the substrate 11 has a vertical dimension of about 40 m.
m, the lateral dimension is about 20 mm, and the thickness is about 1 mm. The first pole portion 41a is formed by using the screen printing method. Sensitive membrane 15x
Is formed by sequentially laminating the first and second individual sensitive films 15a and 15b by repeating the same coating method as described in the first embodiment twice. However, the first individual sensitive film-forming coating liquid is 1 gram of triolein (manufactured by Tokyo Kasei) as a sensitizer, 10 g of vinyl chloride resin (manufactured by Sigma) as a supporting polymer, and dioctyl phthalate (Tokyo Kasei) as a plasticizer. Manufactured by Tokyo Chemical Co., Ltd. and 20 g of
The one composed of 50 grams is used. The second individual sensitive film-forming coating liquid was 1 gram of trioctyl ammonium chloride (manufactured by Tokyo Kasei) as a sensitizer, and 10 grams of vinyl chloride resin (manufactured by Sigma) as a supporting polymer.
Dioctyl phthalate (Tokyo Kasei) 2 as a plasticizer
0 g and a solvent composed of 150 g of tetrahydrofuran (manufactured by Tokyo Kasei) are used. The thickness of each of the first and second individual sensitive films 15a and 15b is 15 μm in terms of the film thickness after drying. Further, the second pole portion 41b is formed by the vacuum vapor deposition method using a comb tooth-shaped vapor deposition mask made of stainless steel at the time of vapor deposition, and the width of the comb tooth is 500 μm. The distance between the teeth is 500 μm.

As a second aspect of the fourth embodiment, an odor sensor 50b having the structure described below is manufactured. FIG. 10 is a diagram provided for the explanation. It is the top view which showed the odor sensor 50b of the 2nd aspect of 4th Example from the sensitive film | membrane 15x upper side, and the sectional view in the II line of this top view.

The odor sensor 50b of the second aspect of the fourth embodiment is the first odor sensor 50b described with reference to FIG. 1 on the insulating substrate 11.
Similarly to the embodiment, the electrode 13 includes a comb-shaped electrode 13 composed of a first pole portion 13a and a second pole portion 13b, and the first individual sensitive film 15a and the second individual sensitive film 15a and the second pole film 15a are provided on the electrode 15 so as to cover it. It comprises a laminate 15x of individual sensitive membranes 15b.
In this case, as the substrate 11, an alumina ceramic plate having a longitudinal dimension of about 20 mm, a lateral dimension of about 10 mm and a thickness of about 1 mm is used. The electrode 13 is composed of a gold thick film electrode formed by the screen printing method as in the first embodiment.
The width of the comb teeth of the electrode 13 is 200 μm, and the distance between the teeth is 200 μm. The first and second individual sensitive films 15a and 15b are the same as those in the first aspect.

On the other hand, as a comparative example of the fourth embodiment, the sensitive film is the first and second individual sensitive films 15 in the fourth embodiment.
The following two types of odor sensors constructed by either a or 15b are manufactured. That is, as the first aspect of the comparative example of the fourth embodiment, the odor sensor of the first embodiment (see FIG. 1)
In the sensitive film 15, 1 gram of triolein (manufactured by Tokyo Kasei) as a sensitizer, 10 g of vinyl chloride resin (manufactured by Sigma) as a supporting polymer, and 20 g of dioctyl phthalate (manufactured by Tokyo Kasei) as a plasticizer. And a solvent formed by using a coating liquid for forming a sensitive film composed of 100 g of tetrahydrofuran (manufactured by Tokyo Kasei) as a solvent. As a second aspect of the comparative example of the fourth example, the first
The odor sensor (see FIG. 1) of the embodiment, which is a sensitive film 15
1 g of trioctyl ammonium (Tokyo Kasei) as a sensitizer, 10 g of vinyl chloride resin (Sigma) as a supporting polymer, 20 g of dioctyl phthalate (Tokyo Kasei) as a plasticizer, and tetrahydrofuran as a solvent. (Manufactured by Tokyo Kasei) Formed by a coating method using a coating solution for forming a sensitive film composed of 100 grams.
In each of the comparative examples, the film thickness of the sensitive film 15 is 20 μm in terms of the film thickness after drying.

Next, two kinds of odor sensors of the first and second aspects of the fourth embodiment and two kinds of odor sensors of the first and second aspects of the comparative example of the fourth embodiment, a total of four. The response characteristics of three kinds of odor sensors to the odor substances of 3-methylcyclopenten-1-one and benzaldehyde are measured according to the procedure of the first embodiment. That is, the resistance value of the sensitive film of the odor sensor is measured when the chamber 21 in FIG. 2 is set to a fresh air atmosphere filtered with activated carbon and the odor substance is set to a concentration atmosphere of 10 ppm. The concentration of the odorous substance is 10 p when the resistance value when the chamber is fresh air is set to 1
The change rate of the resistance value in the case of pm is calculated. The results are shown in Table 7. In addition, in Table 7, the odor sensors of the fourth example and the comparative example were compared with each other for benzaldehyde.
The selectivity of -methylcyclopenten-1-one is shown by the ratio of the resistance change rates to each odor substance.

As is clear from Table 7, the odor substance 3
Regarding -methylcyclopenten-1-one, the resistance conversion ratios of the examples are smaller than those of the comparative examples, and thus the odor sensor of the examples has higher sensitivity than the comparative examples. I understand. Further, regarding the selectivity of 3-methylcyclopenten-1-one for benzaldehyde, it is found that the examples have selectivity of 8 times and 4.5 times. On the other hand, in the comparative example, it is 1 times, and it can be seen that there is no selectivity. From this, it is understood that the odor substance selectivity of the odor sensor can be improved by selecting the individual sensitive film.

In the fourth embodiment, the number of stacked individual sensitive films and the sensitivity of the stacked individual sensitive films can be arbitrarily set according to the design of the odor sensor.

1-5. Description of Fifth Embodiment of First and Second Inventions Next, as a fifth embodiment, an electrode which comprises a sensitive film made of a plurality of individual sensitive films having different sensitivities and which measures electric characteristics of the sensitive film. And a lower electrode, an intermediate electrode, and an upper electrode. Further, the plurality of individual sensitive films are sequentially laminated with the intermediate electrode interposed, and the lower electrode is provided on the lower surface of the lowermost individual sensitive film. An example of the odor sensor in which the upper electrode is provided on the upper surface of the uppermost individual sensitive film will be described. FIG. 11 and FIG. 12 are diagrams provided for explaining one aspect thereof. In particular, FIG. 11 is a plan view showing the odor sensor 60a according to the first aspect of the fifth embodiment as seen from above and a cross-sectional view taken along the line I-I of this plan view, and FIG. It is explanatory drawing of an example of the planar shape of an electrode.

The odor sensor 60a according to the first embodiment of the fifth embodiment has the thickness of gold, which is the lower electrode 61a as a part of the electrode 61 for measuring the electrical characteristics of the sensitive film, on the insulating substrate 11. A solid electrode made of a film is provided, a first individual sensitive film 15a is provided on the lower electrode 61a so as to cover the lower electrode 61a, and an intermediate electrode 61b as a part of the electrode 61 is provided on the first individual sensitive film 15a. A comb-teeth-shaped electrode made of a vapor-deposited film of aluminum is provided, a second individual sensitive film 15b is provided on the intermediate electrode 61b so as to cover it, and a part of the electrode 61 is provided on the second individual sensitive film 15b. Electrode 61 as
The electrode is a comb-tooth-shaped electrode made of a vapor-deposited film of aluminum which is c. By making each of the upper electrode 61c and the intermediate electrode 61b into a comb-teeth shape, the sensitive film 15x can be brought into contact with the measurement atmosphere, so that the contact of the odor substance with the sensitive film can be secured. The planar shapes of the upper, middle and lower electrodes 61c, 61b, 61a in the case of this embodiment are shown in FIG.
These are shown in (A) to (C), respectively. Here, as the substrate 11, in this case, the vertical dimension is approximately 40 mm and the horizontal dimension is approximately 20 mm.
An alumina ceramic plate having a thickness of 1 mm and a thickness of about 1 mm is used. The lower electrode 61a is formed by using the screen printing method. The first sensitive film 15a comprises 1 g of oleylamine (manufactured by Tokyo Kasei) as a sensitizer, 10 g of vinyl chloride resin (manufactured by Sigma) as a supporting polymer, and dioctyl phthalate (manufactured by Tokyo Kasei) as a plasticizer.
And 20 g of tetrahydrofuran and 150 g of tetrahydrofuran (manufactured by Tokyo Chemical Industry Co., Ltd.) as a solvent, are used to form a sensitive film. Intermediate electrode 61b
Is formed by vacuum vapor deposition using a comb-shaped deposition mask made of stainless at the time of vapor deposition, and the width of the comb teeth is 500 μm and the distance between the teeth is 500 μm. The second individual sensitive film 15b is 1 gram of trioctyl ammonium chloride (manufactured by Tokyo Kasei) as a sensitizer, 10 g of vinyl chloride resin (manufactured by Sigma) as a supporting polymer, and dioctyl phthalate (manufactured by Tokyo Kasei) as a plasticizer. And 20 g of tetrahydrofuran and 150 g of tetrahydrofuran (manufactured by Tokyo Chemical Industry Co., Ltd.) as a solvent, are used to form a sensitive film. The upper electrode 61c was formed in the same procedure as the intermediate electrode 61b. The odor sensor 60a according to the first aspect of the fourth embodiment.
As shown in FIG. 11, three types of signals can be obtained by using three terminal pairs of a negative terminal, a negative terminal, and a negative terminal.

As a second aspect of the fifth embodiment, an odor sensor 60b having the structure described below is manufactured. 13 and 14 are diagrams provided for the description. In particular, FIG. 13 shows the odor sensor 60b of the second aspect of the fifth embodiment.
Of the plan view from above and I- of this plan view
FIG. 12 is a cross-sectional view taken along the line I, and FIG. 12 is an explanatory view of an example of the planar shape of each electrode provided in this odor sensor.

The odor sensor 60b of the second mode of the fourth embodiment is an example using three individual sensitive films of the first to third individual sensitive films 15a to 15c, and Each individual sensitive film is shaped so as to expose a part of the other individual sensitive film directly below it. In this example, in the first to third individual sensitive films 15a to 15c, the lower layers are exposed by reducing the plane area of the upper layers. In the region I where only the first sensitive film 15a is provided as the sensitive film, the electrodes are the lower electrode 61a and the first upper electrode 61.
In the region II, which includes the first and second sensitive films 15a and 15b as sensitive films, the electrodes are the lower electrode 61a, the first intermediate electrode 61ba, and the second upper electrode 61cb.
In the region III having the first, second and third sensitive films 15a, 15b and 15c as sensitive films, the electrodes are the lower electrode 61a, the second intermediate electrode 61bb and the third intermediate electrode 61bc. The third upper electrode 61cc. Each lower electrode 61a, each intermediate electrode 61ba-61b
14A to 14D show examples of the planar shapes of c and the respective upper electrodes 61ca to 61cc. The odor sensor 60b according to the second aspect of the fifth embodiment can be manufactured by a procedure similar to the procedure for manufacturing the odor sensor 60a according to the first aspect, and therefore the description thereof will be omitted.

The odor sensor 6 according to the second aspect of the fifth embodiment.
0b, as shown in FIG.
Terminal, -terminal, -terminal, -terminal,
Nine types of signals can be obtained by using a total of nine terminal pairs of the negative terminal, the negative terminal, the negative terminal, and the negative terminal. At each of the three terminal pairs of the negative terminal, the negative terminal, and the negative terminal, the signals of the first to third individual sensitive films alone are obtained, and the two terminal pairs of the negative terminal and the negative terminal, respectively. Gives the signal of a single-layer sensitive film with different sensitive films on top, and the signal of a single-layer sensitive film with two different types of sensitive films on top of the negative terminal pair. Obtained, and-terminal,
2 for each of the three pairs of terminals
The signal of the sensitive film in the state where the types of individual sensitive films are stacked is obtained, and the signal of the sensitive film in the state where the three types of individual sensitive films are stacked is obtained for the negative terminal pair.

In the odor sensor of the fifth embodiment, various information can be obtained by combining various sensitive films. By processing a large number of these pieces of information by, for example, neuronet or fuzzy, it becomes possible to perform odor information processing that is closer to that of living things.

2. Description of Third Invention In the above, the respective embodiments of the first and second inventions have been described. When using the conventional odor sensor not related to the first and second inventions for odor measurement including the odor sensor of the first and second inventions, a sensor unit capable of effectively performing odor detection is desired. . This third invention relates to such an odor sensor unit. A description will be given below with reference to some embodiments.

2-1. Description of the first embodiment of the third invention This first embodiment is intended to ensure that a gas containing an odor substance makes good contact with the odor sensor. FIG. 15 (A) is a diagram for explaining the one mode thereof, and the container 7 having the odor sensor unit 70 of the first mode of the first embodiment.
FIG. 3 is a diagram showing the inside of the device 3 as seen through.

The odor sensor unit 70 of the first embodiment of the third invention comprises an odor sensor 71, a container 73 for accommodating the odor sensor 71, and an upper passage provided on the upper wall of the container 73. It has a pore 75a and a lower vent hole 75b provided in the wall portion on the lower end side of the container 73. Note that FIG.
In (A), 79a is a smoke detection photodiode, and 79b is a smoke detection light source (for example, a light emitting diode).

The odor sensor 71 is not particularly limited,
The odor sensor, which is composed of an organic thin film whose electrical characteristics change in response to odors, has excellent odor selectivity.
This is preferable because the measurement system can be easily simplified. For example,
Each odor sensor described in the embodiments of the first and second inventions is suitable. In this embodiment, the odor sensor of the first embodiment of the first and second inventions (see FIG. 1) is used, in which 1 g of oleylamine (manufactured by Tokyo Kasei) as a sensitizer and vinyl chloride resin (manufactured by Sigma) as a supporting polymer. ) 10 g, dioctyl phthalate (Tokyo Kasei) 20 g as a plasticizer, and tetrahydrofuran (Tokyo Kasei) as a solvent
An odor sensor having a sensitive film formed by using a coating liquid composed of 100 grams is used. Further, the material, shape, etc. of the container 73 are not particularly limited and may be arbitrary according to the design of the odor sensor unit. The container 73 of this embodiment
Is composed of an iron cylindrical container having a diameter of 80 mm and a height of 140 mm. Upper ventilation hole 75a and lower ventilation hole 75b
The number, size and shape of the odor sensor units can be arbitrarily set according to the design of the odor sensor unit. In this case, the upper vent 75
Both a and the lower ventilation hole 75b have a diameter of 8 mm. Further, in this case, six upper vent holes 75a and six lower vent holes 75b are provided along the circumference of each of the upper end portion and the lower end portion of the container 73.

As a second aspect of the second embodiment, in addition to the structure of the odor sensor unit of the first aspect, in order to promote the movement of gas in the atmosphere to be measured in the vessel 73, An odor sensor unit 70b (see FIG. 15B) including a heating means 77 for raising the ambient temperature in 73 is produced. The heating means 77 is not particularly limited and can be composed of various known heaters. Further, the heating means 77 may include a temperature control mechanism. Each odor sensor unit 70 of the first and second aspects
In a and 70b, the lower ventilation hole 75b functions as an introduction hole for the gas to be measured, and the upper ventilation hole 75a functions as an outlet for the gas to be measured.

On the other hand, as the odor sensor unit of the comparative example, as shown in FIG. 17, the upper vent hole 75a and the heating means 77 are removed from the odor sensor units 70a and 70b of the first embodiment (the sensor of the first embodiment). In the unit, an odor sensor unit having a configuration (excluding the upper vent hole 75a) is manufactured.

These three types of odor sensor units are shown in FIG.
Evaluation is carried out as described below according to the evaluation method described in the first embodiment of the first and second inventions using the measurement system shown in FIG. However, benzaldehyde is used as the odor substance in this case. Further, the evaluation chamber 21 is replaced with a chamber having a volume of 80 liters in order to accommodate the sensor unit. In the evaluation using the odor sensor unit (having the heating means 77) according to the second aspect of the embodiment, the heating means 77 is used so that the temperature inside the container 73 is higher than the outside temperature by 5 degrees. The inside of the container 73 is heated. As shown in FIG. 16, the sensor unit to be evaluated is placed in the chamber 21, and benzaldehyde is introduced into the chamber 21 at a concentration of 10 ppm from when the chamber 21 was fresh air filtered by activated carbon. The resistance value until the resistance value stabilizes is monitored by each of the above three types of odor sensor units. The results are shown in FIG. 18 with the vertical axis indicating sensitivity and the horizontal axis indicating time. Here, the sensitivity on the vertical axis is
It is a value obtained by dividing the resistance value after the inside of the chamber was made a benzaldehyde atmosphere having a concentration of 10 ppm by the resistance value of the odor sensor when the inside of the chamber was fresh air (a resistance value change rate similar to the above-described examples). It can be seen from FIG. 18 that in the odor sensor unit 70a according to the first embodiment of the present embodiment, the time required for the resistance value to stabilize after the benzaldehyde atmosphere having a concentration of 10 ppm is about 2.5 minutes. It can be seen that the odor sensor unit 70b of the second aspect of the example (which has the upper and lower ventilation holes and the heating means) takes about 1.5 minutes, and the comparative example takes 5 minutes or more. Therefore, it can be seen that the odor sensor unit of the example has a response speed 4 to 2 times faster than that of the comparative example.

2-2. Description of the second embodiment of the third invention In practical use of the odor sensor, the gas to be measured often contains something which is not preferable for the odor sensor. For example, in the case of detecting a scent in a smoldering state (still smoldering state) at the time of fire, the atmosphere of the measurement target contains smoke particles. The smoke particles impair the response characteristics of the odor sensor. Therefore, when the gas to be measured contains a substance that is not preferable for the odor sensor, it is desired to be able to easily remove this. The second embodiment of the third invention is that example. 19 to 21
Is a diagram used for the explanation. In particular, FIG. 19 is a diagram for explaining the odor sensor unit 80 of the second embodiment of the third invention, FIG. 20 (A) is a diagram for explaining an evaluation method of the odor sensor unit, and FIG. 20 (B) is a comparison. FIG. 21 is a diagram for explaining the odor sensor unit 90 of the example, and FIG. 21 is a characteristic diagram showing evaluation results of the example and the comparative example. 19 and 20B show a state in which the inside of the container 83 provided in the odor sensor unit is seen through.

The odor sensor unit 80 of the second embodiment of the third invention comprises an odor sensor 81 and the odor sensor 81.
And a net 85 provided at a position of the case 83 that is located upstream of the odor sensor 81 in the flow of the gas to be measured.

The odor sensor 81 is not particularly limited,
An odor sensor having a sensitive film made of an organic thin film whose electric characteristics change in response to an odor is preferable because it has excellent odor selectivity and is easy to measure. For example, the odor sensors described in the embodiments of the first and second inventions are suitable. In this embodiment, the odor sensor of the first embodiment of the first and second inventions (see FIG. 1) is used, in which 1 g of oleylamine (manufactured by Tokyo Kasei) as a sensitizer and vinyl chloride resin (manufactured by Sigma) as a supporting polymer. ) 10 g, 20 g of dioctyl phthalate (manufactured by Tokyo Kasei) as a plasticizer,
And tetrahydrofuran (manufactured by Tokyo Kasei) 10 as a solvent
An odor sensor having a sensitive film formed by using a coating solution of 0 gram is used. The material and shape of the container 83 are not particularly limited, and may be arbitrary according to the design of the odor sensor unit. The container 83 of this embodiment is a cylindrical container whose upper and lower ends are open.
The material of the net 85, the shape of the eyes, the density of the eyes, and the like can be arbitrary according to the design of the odor sensor unit. In this embodiment, a screen-printing stainless wire net (made by Mesh Kogyo Co., Ltd., having a hole diameter of 20 μm and 500 mesh) is used as the net 85. The number of nets 85 to be used can be arbitrary according to the design of the odor sensor unit, but in this embodiment, two types of odor sensor units are produced, one using the stainless steel wire net and one using the stainless steel wire net. In the configuration using two nets, both nets are provided 5 cm apart.

On the other hand, as shown in FIG. 20B, a odor sensor unit 90 of a comparative example having a structure in which the net 85 is removed from the structure of the odor sensor unit 80 of the embodiment is manufactured.

FIG. 1 shows these three types of odor sensor units.
Evaluation is performed according to the evaluation method described in the first embodiment of the first and second inventions using the measurement system shown in FIG. However, in this measurement system, a heater 101 (nichrome wire in this case) is provided in the chamber 21, and the filter paper 103 is placed on the filter paper 101. This is because the electric power is applied to the heater 101 to heat it, so that the filter paper 103 is in a smoldering state. As a result, the odorous substance is dropped on the filter paper 25 to generate the atmosphere of the odorous substance in the chamber 21 by the evaluation method so far, and the smoke generation state can be generated in the chamber 21. As shown in FIG. 20 (A), the chamber 21
Put the sensor unit to be evaluated in the
Fill 1 with fresh air filtered through activated carbon. Then, the resistance value (initial resistance value) of the odor sensor at this time is measured. Next, the atmosphere in the chamber 21 is changed from the following (a) to
Various states among the states of (d) are sequentially changed (here, changed as shown in the horizontal axis of FIG. 21), and the resistance value of the odor sensor in each state is measured. Then, the value obtained by normalizing these resistance values with the above-mentioned initial resistance value (resistance change rate so far) is taken as the sensitivity. The results are shown in FIG. 21 in which the horizontal axis represents the changed state in the chamber and the vertical axis represents the above sensitivity.

(A). When the inside of the chamber 21 is fresh air filtered with activated carbon.

(B). When the inside of the chamber is an atmosphere of benzaldehyde with a concentration of 10 ppm.

(C). When the filter paper 103 is heated by the heater 101 to generate smoke and a burning odor.

(D). When the above (b) and (c) coexist.

As is clear from comparison of the characteristics of the embodiment and the comparative example of FIG. 21, the odor sensor unit of the embodiment detects the odor with good reproducibility each time the state inside the chamber 21 is changed. . This is because, in the odor sensor unit of the embodiment, it is possible to effectively prevent smoke particles from reaching the odor sensor by the net. In addition, also in the example, it was found that the one having two nets had a slightly smaller response, but the reproducibility in repeated odor detection was excellent.

In the third aspect of the invention, a more useful odor sensor unit can be obtained by using the odor sensor unit having both the structure of the first embodiment and the structure of the second embodiment.

In the embodiment of the first invention described above, the coating solution for forming the sensitive film had a specific composition, but this is merely an example within the scope of the invention. It is obvious that the mixing ratio of the sensitizer to the supporting polymer and the mixing ratio of the plasticizer can be changed in consideration of the kind of the sensitizer used, the specifications required for the odor sensor, and the like.

[0099]

[Table 1]

[0100]

[Table 2]

[0101]

[Table 3]

[0102]

[Table 4]

[0103]

[Table 5]

[0104]

[Table 6]

[0105]

[Table 7]

[0106]

As is apparent from the above description, according to the odor sensor of the first invention of the present application, a sensitive film containing an organic sensitizer and a supporting polymer, the electrical characteristics of which are changed in response to the odor, It is equipped with electrodes for measuring the electrical properties of the sensitive membrane. Therefore, when an atmosphere containing an odor substance touches the sensitive film and the electrical property of the sensitive film changes, the change in the electrical property can be taken out to the outside by the electrode, and the odor can be detected. Therefore, the odor can be detected with a simple configuration in which the conductance such as the electric resistance value is measured. In addition, since an organic sensitizer is used, it is considered that the sensitivities to odorous substances composed of organic substances are higher than in the case where it is not. Therefore, it is possible to detect the odor concentration in the order of ppm. Further, the specificity for the odorant can be controlled by selecting the sensitizer.

Further, according to the second invention of this application, there is provided an odor sensor comprising a sensitive film composed of an organic thin film whose electrical characteristics change in response to an odor, and electrodes for measuring the electrical characteristics of the sensitive film. Various types of odor sensors are available, depending on the application and desired characteristics. For example, in the structure in which the electrodes are embedded in the sensitive film and both surfaces of the sensitive film are in contact with the measurement atmosphere, the area in contact with the gas to be measured can be widened as compared with the case where it is not so that improvement in sensitivity can be expected.
Further, in the configuration in which the sensitive film is a laminated body of a plurality of individual sensitive films having different sensitivities, the individual sensitive film serves as a filter of the individual sensitive film in the lower layer, so that the lower individual sensitive film is specific. The selectivity for odorants sensitive to is increased. Also, in the configuration with upper, middle (or more than one) and lower electrodes and individual sensitive films between the electrodes, it is possible to select multiple pairs of electrodes for measuring electrical characteristics, if necessary. Since changes in the electrical properties of the membrane can be monitored, a great deal of information about odors can be obtained. Therefore, odor detection closer to that of living things can be expected. Furthermore, in this configuration, when each individual sensitive film has a shape that exposes a part of the other individual sensitive film immediately below it, information unique to each individual sensitive film is also obtained.

Further, in the odor sensor unit of the third aspect of the present invention, in the structure provided with the upper and lower vents or further the heating means, the flow of gas between the inside and outside of the container of the sensor unit is promoted so that the odor can be easily sensed. You get units. Further, in the configuration in which the net is provided, the object that interferes with the sensing of the odor in the measurement atmosphere, for example, smoke particles, is trapped by the net, so that the reproducibility of the odor detection can be further enhanced. Further, in the configuration in which the upper and lower ventilation holes and / or the heating means is further provided with a net, more stable odor detection can be performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of the first and second inventions.

2A and 2B are explanatory views of a first embodiment or a second embodiment of the first invention and the second invention, and an illustration of an odor sensor evaluation method.

3A and 3B are explanatory views of a second embodiment of the first and second inventions.

FIG. 4 is an explanatory view of the second embodiment of the first and second inventions following FIG.

FIG. 5 is an explanatory view of the second embodiment of the first and second inventions following FIG.

FIG. 6 is an explanatory view of the second embodiment of the first and second inventions, following FIG.

7 (A) and 7 (B) are explanatory views of the second embodiment of the first and second inventions following FIG. 6.

FIG. 8 is an explanatory diagram of a third embodiment of the first and second inventions.

FIG. 9 is an explanatory diagram of a fourth embodiment of the first and second inventions.

FIG. 10 is an explanatory view of the fourth embodiment of the first and second inventions, following FIG.

FIG. 11 is an explanatory diagram of a fifth embodiment of the first and second inventions.

12A to 12C are explanatory views of the fifth embodiment of the first and second inventions following FIG.

FIG. 13 is an explanatory view of the fifth embodiment of the first and second inventions, following FIG.

14A to 14D are explanatory views of the fifth embodiment of the first and second inventions following FIG.

15A and 15B are explanatory views of a first embodiment of the third invention.

FIG. 16 is an explanatory diagram of an evaluation method of an odor sensor unit.

FIG. 17 is an explanatory diagram of an odor sensor unit of a comparative example.

FIG. 18 is a diagram showing evaluation results of the odor sensor unit of the first example.

FIG. 19 is an explanatory diagram of the second embodiment of the third invention.

20A and 20B are diagrams for explaining a second embodiment of the third invention, FIG. 20A is an explanatory diagram of an evaluation method of an odor sensor unit, and FIG. 20B is an odor of a comparative example. It is explanatory drawing of a sensor unit.

FIG. 21 is a characteristic explanatory view of the odor sensor unit of the second embodiment of the third invention.

[Explanation of symbols]

 10: Odor sensor of the first embodiment 10a: Lead wire 11: Insulating substrate 13: Electrode for measuring electric characteristics of sensitive film 13a: First pole portion 13b: Second pole portion 15: Sensitive agent and supporting polymer Sensitive film 15a: First individual sensitive film 15b: Second individual sensitive film 15x: Sensitive film in the fourth example (laminate of individual sensitive films) 30: Odor sensor of the second example 31: Sensitive Electrodes embedded in the film 31a: first pole portion 31b: second pole portion 33: support 40: odor sensor of the third embodiment 41: electrode of the third embodiment 41a: first pole portion 41b: first Bipolar part 50a: odor sensor of the first aspect of the fourth embodiment 50b: odor sensor of the second aspect of the fourth embodiment 60a: odor sensor of the first aspect of the fifth embodiment 60b: fifth odor sensor of the fifth embodiment Two-mode odor sensor 61a: lower electrode 61b: intermediate electrode 61c: Upper electrode 70a: Odor sensor unit of the first aspect of the first embodiment 70b: Odor sensor unit of the second aspect of the first embodiment 80: Odor sensor unit of the second embodiment

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Saito 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (18)

[Claims] 1. An odor characterized by comprising a sensitive film containing an organic sensitizer and a supporting polymer, the electrical properties of which are changed in response to an odor, and an electrode for measuring the electrical properties of the sensitive film. Sensor. 2. The odor sensor according to claim 1, wherein the sensitizer is at least one selected from dioctyl phthalate, dioctyl phosphate, cholesterol, trioctyl ammonium chloride, oleylamine and triolein. Characteristic odor sensor. 3. The odor sensor according to claim 1, wherein the supporting polymer is polyvinyl chloride. 4. The odor sensor according to claim 1, wherein the sensitive film further contains a plasticizer. 5. The odor sensor according to claim 4, wherein the plasticizer is dioctyl phthalate. 6. An odor sensor comprising a sensitive film composed of an organic thin film whose electrical properties change in response to an odor, and an electrode for measuring the electrical properties of the sensitive film, wherein the first pole part of the electrode And the second pole portions are provided side by side on a common insulating substrate, and the sensitive film is provided on both the first pole portion and the second pole portion over both pole portions. . 7. An odor sensor comprising a sensitive film composed of an organic thin film whose electrical characteristics change in response to an odor, and an electrode for measuring the electrical property of the sensitive film, wherein the electrode is provided in the sensitive film. An odor sensor, which is embedded and has a structure in which both sides of the sensitive film are in contact with a measurement atmosphere. 8. An odor sensor comprising a sensitive film composed of an organic thin film whose electrical properties change in response to an odor, and an electrode for measuring the electrical property of the sensitive film, wherein the first pole part of the electrode And a second pole portion facing each other with the sensitive film sandwiched therebetween. 9. An odor sensor comprising a sensitive film composed of an organic thin film whose electrical characteristics change in response to an odor, and electrodes for measuring the electrical properties of the sensitive film, wherein the sensitive films have different sensitivities. The odor sensor is characterized by comprising a laminate of a plurality of individual sensitive films shown in FIG. 10. The odor sensor according to claim 8, wherein at least one of the first pole portion and the second pole portion of the electrode has gas permeability. Sensor. 11. An odor sensor comprising a sensitive film composed of an organic thin film whose electrical characteristics change in response to an odor, and an electrode for measuring the electrical characteristics of the sensitive film, wherein different sensitive layers are used as the sensitive film. A plurality of individual sensitive films exhibiting a property, a lower electrode, an intermediate electrode and an upper electrode are provided as the electrodes, and the plurality of individual sensitive films are sequentially laminated with the intermediate electrode interposed, An odor sensor characterized in that the lower electrode is provided on the lower surface of the individual sensitive film, and the upper electrode is provided on the upper surface of the uppermost individual sensitive film. 12. The odor sensor according to claim 11, wherein at least one of the upper electrode and the lower electrode has gas permeability. 13. The odor sensor according to claim 11, wherein each individual sensitive film is shaped so as to expose a part of another individual sensitive film immediately below it. 14. An odor sensor, comprising: an odor sensor, a container for housing the odor sensor, and ventilation holes provided in a wall portion on an upper end side and a wall portion on a lower end side of the container. unit. 15. The odor sensor unit according to claim 14, further comprising: increasing the atmospheric temperature in the container in order to promote the movement of the gas of the measurement target atmosphere in the container. An odor sensor unit comprising a heating means for 16. An odor sensor unit, comprising: an odor sensor; and a net provided at a position corresponding to an upstream side of a flow of a gas to be measured with respect to the odor sensor. 17. An odor sensor unit comprising the odor sensor unit according to claim 14 or 15 equipped with the net according to claim 16. 18. The odor sensor unit according to any one of claims 14 to 17, wherein the odor sensor according to any one of claims 1 to 13 is used as the odor sensor. unit.