JPH0377050A - Chemical material sensor - Google Patents

Abstract

PURPOSE:To accurately detect and determine a chemical material by irradiating a sensor film with the light emitted from a light emitting element and detecting the reflectivity thereof by a light receiving element. CONSTITUTION:This sensor has the sensor film 12 contg. both a dyestuff and a chemical material sensitive compd. on the surface of a base material 11. The light emitting element 21 and the light receiving element 22 are installed on the rear of the base body 11. These elements and body are integrally housed in a casing 30. A control means 4 for controlling light emission time, light emission intervals, light emission intensity, etc., is connected to the element 21 and a detecting means 5 for detecting and measuring the reflected light is connected to the element 22, respectively. The light emitted from the element 21 is made incident from the rear surface of the base body 11 and the specular reflection of the light by the sensor film 12 is detected by the element 22. The chemical material to be detected is detected and determined from a change in the reflectivity. The reflected light by a dyestuff film is detected if the sensor film 12 is laminated films.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a chemical substance sensor capable of detecting and quantifying chemical substances.

<Conventional technology> It selectively adsorbs or selectively reacts with specific chemical substances existing in the outside world, and the type and concentration of the chemical substance can be determined from the resulting changes in electrical signals such as resistivity and dielectric constant. Chemical sensors for detection are known.

Such chemical sensor materials include semiconductors, ceramics, polymers, etc., and are actually applied to the detection and quantification of water vapor, various gases, various ions, etc.

Additionally, sensors using cholesteric liquid crystals are known [JP-A-53-76094, JP-A-58-426].
No. 85, Tsukahara, Mechatronics Special Edition, Dan-J, 103
(1981), Sensor Technology, L Yuyue, 62 (198
7), Yueyu 1, 97 (1987) 7 (1,
2>, 87 (1987)].

This device utilizes the color change of liquid crystal.

On the other hand, with the recent development of office automation equipment, etc., there is a demand for various sensors that can operate stably and accurately even in environments with strong electric fields such as copying machines, so sensors that use optical detection and quantitative methods are advantageous. It is.

Among these, optical methods utilize the change in the amount of light absorption or fluorescence (fluorescence quenching) caused by the reaction of certain dyes or compounds with gas substances or the formation of charge transfer complexes. Detection and quantitative methods are known.

For example, those utilizing the discoloration caused by the reaction of N,N-dimethylaniline with 02 (JP-A-57-t OO337) Poly-2-bala(methacroylaminophenyl)-5-
A method that utilizes discoloration caused by the reaction of phenyl-1,3-oxazole with NH, or amines (Japanese Patent Application Laid-Open No. 60-2023)
No. 34) There is a method (Japanese Unexamined Patent Publication No. 178646/1983) that utilizes the change in fluorescence caused by the reaction of 02 with a tris(4,7-diphenyl-1,10-phenanthroline) Ru complex.

Furthermore, a method utilizing absorption change in bromothymol blue film due to NH (Nikkei Sangyo Shimbun, December 1988)
(Published on May 14th) Utilizing fluorescence change in LB film using squarylium dye and fatty acid as film-forming compounds by No. [Chemical Society of Japan Spring Annual Meeting Proceedings 3 II HO
7 (1988), Nikkei Sangyo Shimbun, June 1988 lO
Issued on a daily basis] are also examples.

Although there are few examples of devices that utilize light reflection, devices that use metal films or metal salts are being considered.

For example, one that utilizes the reaction between palladium potassium sulfite and CO (Japanese Patent Application Laid-open No. 79141/1983) Hg B
One that utilizes the reaction between r
No. 42645) This method utilizes the corrosion of a metal film by SF4 (Japanese Patent Application Laid-open No. 8066/1983).

In addition, humidity sensors that utilize changes in refractive index by providing an optical fiber or an optical fiber with a heat-absorbing material as a cladding (Japanese Patent Application Laid-open No. 61-217744,
2-9255, JP-A-62-204143, etc.) Those using inorganic compounds that change color due to moisture absorption (JP-A-54-80190, JP-A-61,-139478)
No.) Those that utilize changes in absorption coefficient, changes in scattering intensity, or color development due to hygroscopic resin etc. (Japanese Patent Laid-Open No. 56-67738)
No., JP-A-56-110039, JP-A-58-216
No. 936) Furthermore, a method utilizing a change in diffused reflection by using a transparent body with unevenness and a moisture absorbent (Japanese Unexamined Patent Publication No. 59-2
No. 04742) or one that utilizes the reflected light and transmitted light of a mirror consisting of two types of dielectric layers with different refractive indexes (No. 04742).
Japanese Unexamined Patent Publication No. 62-39744) has been proposed.

However, no proposals have been made for utilizing the reflection of pigmented light.

Sensors using semiconductors, ceramics, polymers, etc. as described above generally have a drawback that the film is thick and the response is slow due to the diffusion process of the gas to be detected. Also, there are many things that need refreshing. Furthermore, changes in resistance values are often detected, and since electrical means are used in this way, changes over time are large, for example, under strong electric fields.

In addition, many of the device manufacturing methods involve complicated processes.
Many of the detection circuits and the like are also complicated.

On the other hand, sensors using cholesteric liquid crystals utilize color changes due to changes in pitch, so the wavelength distribution of light reflection varies and is not constant, has low sensitivity, and is highly temperature dependent. There are drawbacks such as.

In addition, when utilizing changes in absorption or fluorescence using dyes, etc., there is a drawback that dyes are limited to dyes that can selectively bind or react with the analyte, such as a gas substance, to be detected or quantified. be. When manufacturing such devices, it is necessary to highly orient the dye molecules when applying the LB film, such as the one that utilizes the fluorescence change in the LB film mentioned above, or it is necessary to align the dye molecules to a high degree when applying the LB film. In many cases, advanced or complicated processes are required, such as those that utilize absorption changes, which require the provision of a reflective film.

Furthermore, in the case of using a metal film or a metal salt, all reactions are irreversible, and even in this case, the combinations of the sensor material and the test substance such as a gaseous substance are limited.

Under these circumstances, the present inventor has previously proposed a chemical sensor having a sensor film containing a chemical sensitive compound and a dye (Japanese Patent Application No. 63-219434, No. 63-219434).
(No. 3-219921, No. 63-263506) The chemical sensor shown in these proposals detects and measures the change in light reflectance of the sensor film caused by the combination of a chemical substance-sensitive compound with a test chemical substance. It is.

<Problems to be Solved by the Invention> The chemical substance sensor proposed above has a simple structure, high precision and quick response, and is also highly durable.

However, when sensing is performed continuously, the temperature of the sensor film increases due to continuous light irradiation, and the degree of binding of the test chemical to the sensor film may change.

For example, when applied to humidity sensors, ammonia sensors, etc., such changes become noticeable.

An object of the present invention is to provide a chemical substance sensor that can detect and quantify chemical substances continuously with high precision, has a fast response, has a simple element configuration, has excellent durability, and is advantageous in terms of cost. .

Means for Solving the Problems> Such objects are achieved by the following inventions (1) to (4).

(1) It has a base, a sensor film formed on the base, a light emitting element, and a light receiving element, the sensor film contains a dye and a chemical substance sensitive compound, and the chemical substance sensitive compound is coated. The light reflectance of the sensor film is configured to change when combined with a test chemical substance, and the light emitted from the light emitting element is irradiated onto the sensor film, and the reflectance is detected by the light receiving element. 1. A chemical substance sensor configured to detect and quantify a test chemical substance by: a chemical substance sensor configured to detect and quantify a test chemical substance, characterized in that the irradiation with the light is performed intermittently.

(2) The chemical substance sensor according to (1) above, wherein the sensor film contains a dye and a chemical substance-sensitive compound in a mixed, compatible or combined manner.

(3) The chemical sensor according to (1) above, wherein the sensor film is a laminated film of a dye film containing a dye and a chemical sensitive film containing a chemical sensitive compound.

(4) The chemical substance sensor according to (3) above, wherein in the laminated film, the dye film is present on the substrate side.

Effect> The chemical sensor of the present invention has a sensor film containing a chemically sensitive compound and a dye, and the physical properties of the film change due to the combination of the chemically sensitive compound and the test chemical. Reflectance changes.

In the present invention, in the chemical substance sensor having such a configuration, the sensor film is irradiated with light intermittently, so that a rise in temperature of the sensor film can be suppressed.

Therefore, even when continuous measurements are performed, the bonding ratio between the chemical substance-sensitive compound and the test chemical substance is stable, and continuous measurements can be performed with high accuracy.

<Specific configuration> Hereinafter, the configuration of the present invention will be explained in detail.

The chemical substance sensor of the present invention has a sensor film containing a dye and a chemical substance-sensitive compound on a substrate.

In the present invention, the sensor film may contain a dye and a chemical substance-sensitive compound in a mixed, compatible or bonded manner; It may also be a laminated film with a chemical substance sensitive film.

In the former case, as shown in FIG. 1, a sensor film 12 containing both a dye and a chemical substance-sensitive compound is provided on the surface of the substrate 11, and a light emitting element 21 and a light receiving element 22 are provided on the back side of the substrate 11. are installed, and these are the casing 3
It is stored integrally within 0.

In the latter case, as shown in FIG. This is similar to the chemical substance sensor shown in Figure 1.

In this case, as shown in FIG. 2, it is preferable that the dye film 122 exists on the substrate 11 side. By forming in this way, detection can be performed from the back side of the substrate.

In the chemical substance sensor shown in FIGS. 1 and 2, the light emitting element 21 has a control means 4 for controlling the light emitting time, the light emitting interval, the light emitting intensity, etc., and the light receiving element 22 has a control means 4 for detecting and measuring reflected light. Detection means 5 for detecting the detection means 5 are respectively connected.

In these sensors, light emitted from a light emitting element 21 is incident on the back surface of the base 11, the specular reflection of the light by the sensor film is captured by a light receiving element 22, and the test chemical substance is detected and quantified from the change in reflectance. . Note that when the sensor film is a laminated film, reflected light from the dye film is detected.

More specifically, in the chemical sensor shown in FIG. 1, the sensor membrane 12 containing a chemical-sensitive compound changes its physical properties when it comes into contact with a test fluid containing a test chemical.

Specifically, the refractive index, film thickness, etc. change due to the chemical substance-sensitive compound and the test chemical substance bonding together.

Since light reflection by the sensor film is due to multiple reflections within the film, the reflectance changes due to changes in the physical properties of the film as described above.

Further, as shown in FIG. 2, when the sensor film 12 is a laminated film, multiple reflections within the dye film 122 are strongly influenced by the interface between the dye film and the chemical substance sensitive film. Therefore, when the chemical substance-sensitive film comes into contact with a test chemical and its physical properties change, the dye film reflectance changes.

Such an action makes it possible to detect and quantify a test chemical substance.

Note that when the sensor film is a laminated film, the film responsible for light reflection may be a multi-reflection film. Therefore, it is not limited to pigment membranes;
Laminated dielectric films can also be used. However, when a metal film is used instead of a dye film, the reflectance on the film surface is high and the multiple reflection effect is small, which is not preferable.

Further, when the sensor film is a laminated film, unlike the case where a chemical substance-sensitive compound and a dye are contained in the same film, there is no need to consider the compatibility between the chemical substance-sensitive compound and the dye. Therefore, since the content of the dye in the dye film can be increased, a sufficient change in reflectance can be obtained, and high sensitivity can be obtained. Furthermore, since chemical substance-sensitive compounds can be selected from a wide range without considering compatibility with dyes, the range of test chemical substances to be tested is expanded. A desired sensitivity can be obtained by controlling the thickness of the dye film.

In the present invention, it is preferable that the light emitting element 21 and the light receiving element 22 are installed close to each other.

That is, by measuring the reflection due to specular reflection at an incident angle of 20" or less, the sensitivity can be increased and the device can be made more compact. Furthermore, the light emitting device 2
By integrally providing the light receiving element 1 and the light receiving element 22 on the back surface of the base 11, the element can be made more compact and its robustness can be improved.

There are no particular limitations on the dye used in the present invention, but the light emitting element 21
So-called bronze, which exhibits specular reflection at least at a single wavelength within the wavelength range of light emitted from the light, e.g. at an incident angle of 20" or less, particularly at an angle of about 5°, of 10% or more, more preferably 20% or more. A pigment with luster is preferred.

This is because when the reflectance is less than 10%, it becomes difficult to detect the test chemical substance as a change in reflectance.

In the present invention, the wavelength of light emitted by the light emitting element is any wavelength in the visible to infrared range.

Furthermore, the dye used in the present invention preferably has an absorption rate of 70% or less, preferably 50% or less at the wavelength used when formed into a dye film, and the maximum wavelength of reflection in the dye film (e.g. Rma
x) is preferably different from the absorption maximum wavelength (λAmax), and in particular, λRmax-k Amax≧
The thickness is preferably 50 nm.

By using such dyes, substantially sufficient sensitivity can be obtained.

Such dyes have a reflectance of 10 at the above wavelengths.
There is no particular restriction as long as it is % or more, but cyanine dyes, azulenium dyes, biryllium dyes, squarylium dyes, croconium dyes, quinone/naphthoquinone dyes,
Specific examples include metal complex dyes, phthalocyanine dyes, naphthalocyanine dyes, and the like.

Furthermore, when using a polymethine dye such as a cyanine dye, a -principal oxygen quencher may be used, and the quencher in this case may be a metal complex, especially a Ni complex, such as a dithiol type (especially a bisphenyldithiol type). ) are preferably Ni complexes or amine compounds.

In the present invention, the chemical-sensitive compound contained in the sensor membrane or the chemical-sensitive membrane is a compound that binds reversibly or irreversibly to a specific chemical substance, and may be selected depending on the chemical substance to be tested.

More specifically, chemically sensitive compounds have various bonding states between their molecules and the target chemical substance to be tested, and these bonds include various reactions, covalent bonds, ionic bonds, etc. In addition to various bonds such as , coordinate bonds, adsorption, absorption, etc. are included.

The binding and desorption between the chemical substance-sensitive compound and the test chemical substance is preferably reversible, but may be irreversible.

When the present invention is applied to a humidity sensor, that is, when the test chemical substance is water, the chemically sensitive compounds include:
Use hydrophilic compounds.

As a hydrophilic compound, the solubility parameter (solubH
ity para@eter SP value δ” (CE p
)l/ICED, cohesive energy density cohesi
veenergy density) is 17 (MJ/
m”)”” or more, especially 17 to 40 (MJ/m”)””
More preferably 18 to 40 (MJ/+”) ””
More preferably 20 to 3° (MJ/m”)
Preferably.

The solubility parameters are calculated according to the following or from actual measurements.

A. Calculated from heat of vaporization δ'' (EV/y) +zt Ev: Calculated from molar evaporation energy (J/a+ol), V: Calculated from molar volume (m''/mol).

However, in the case of polymers, they do not vaporize, so follow B and C below.

B. Actual measurements based on compatibility (1) Swelling degree In particular, cross-linked three-dimensional polymers are insoluble in solvents, so observe the degree of swelling and determine the S of the solvent with the greatest swelling effect.
Let the P value be the SP value of the polymer (D, Mangara
J, Macromol, chew, 65.2
9 (1963)) (2) Viscosity In a solvent with good compatibility, the polymer chains are spread, so the viscosity becomes high. The intrinsic viscosity η is measured in various solvents, plotted against the SP value of the solvent used, and the SP value showing the maximum is taken as the SP value of the polymer (D, Mangaraj
, S., Patra and S., B., Rath, Ma.
klomol, cheap, 67.84 (196
3).

65.39 (1963), G. M. Bistow an
d W, F. Watson.

Trans, Faraday, Soc, 54.1
742 (1958)).

(3) Turbid point titration method The polymer's prize solvent is added dropwise to the polymer solution, and the amount of the polymer's S
Determine the P value (K, W, 5uhand D, H,
C1arke, J., Polyo+, Sci., 5.
1671 (1967), K., W., Suh and J.
, M., Corbett, J., Appl.

Polym, Sci., 12.2359 (1968)
) Calculation from C0 chemical structure Small's method (P, Sa+aIL, J, AI)p
1, Chem, 3°71 (1953)), and preferably the Fedors method (R,F,
Po1ya+, Eng, Sci, 14147 (1
974)), it may be calculated from the evaporation energy Δei and molar volume Δvi of atoms and atomic groups.

In the present invention, one or more of the above hydrophilic compounds A,
The sp value calculated from either B or C is 17 (MJ
/m")"" or more is sufficient.

Further, it is preferable that one or more of the hydrophilic compounds used has a contact angle with water of 70@ or less, particularly 10 to 70' when formed into a single layer.

Next, among such chemical substance-sensitive compounds, specific examples of hydrophilic compounds include the following.

(2) Hydrophilic polymer compound A hydrophilic polymer compound having a polar group is preferable because it has a particularly preferable SP value or contact angle with water.

Examples of polar group-containing polymer compounds include oxygen-containing polymer compounds such as carbonyl groups and ether groups, and NH group-containing polymer compounds, as well as polymer compounds containing cyano groups, halogens, etc. There is something.

a) Water-absorbing polymeric anion salt (particularly a salt that reversibly absorbs water) For example, sodium alginate, sodium polyacrylate, sodium polymethacrylate, sodium poly(4-styrenesulfonate), sodium polyvinyl phosphate, polyvinyl Ammonium phosphate, sodium polyglutamate, etc.

b) Polyelectrolytes such as polyethyleneimine hydrochloride, polyethyleneimine/polystyrene sulfonic acid, polyN-methylpyridinium chloride, etc.

C) Thermosetting resins phenolic resins, furan resins, alkyd resins, epoxy resins, melamine resins, unsaturated polyester resins, etc.

d) Thermoplastic resin polyvinyl acetate, polyacrylate, polymethacrylate, polyvinyl chloride, polyacrylonitrile, polyvinyl alcohol, polyether, polyamide, polyester, polyurethane, polyvinyl ketone, polyvinylidene chloride, polyvinylpyrrolidone (pvp), polyalkylene ( ethylene) glycol, polyacrylamide, PV
A-ethylene copolymer, etc.

e) Cellulose-based acetylcellulose, triacetylcellulose, nitrocellulose, acetylbutylcellulose, propionylcellulose, ethylcellulose, carboxymethylcellulose, etc.

f) Natural polymers and their derivatives casein, amylose, polyglycine, modified starch (
grafted starch) etc.

g) These blends or copolymers may be crosslinked to have a three-dimensional structure.

These polymer compounds are preferably used because they have good film properties and high water resistance.

(2) Hydrophilic low-molecular organic compound (h) Water-absorbing organic metal salt (particularly a salt that absorbs water reversibly) For example, sodium acetate, sodium potassium tartrate,
such as sodium lactate.

(2) Hydrophilic inorganic compounds 1) Water-absorbing inorganic metal salts (especially salts that absorb water reversibly) For example, L i Cl2z , CaC42g , CoCJ
Metal halides such as 2s.

j) Hydrophilic gels, such as colloidal silica or silicates such as silicon alkoxides, hydrolysates of titanates, aluminates, zirconates, etc.

One or more of these compounds may be used, and a humidity sensor that detects water vapor can be obtained.

In addition, when using ammonia as the test chemical substance, bromothymol blue, thymol blue, acridine 1/1
poly-2-bala (methacroylaminophenyl)
-5-phenyl-1,3-oxazole or the like is used.

Furthermore, crown ether is used when the chemical substance to be tested is alkali metal or alkaline earth metal ions such as Na'', )('', etc., or various metal ions such as Ag'').

As a crown ether, benzo-15-crown 5
(Test chemical substance; N a ”) *Dibenzoviridino 18-crown-6 (test chemical substance; various metal ions), Cryptofix 222CC (manufactured by Merck) (test chemical substance; 0), long chain Introduced azacrown ether (test chemical substance; Ag'') (for example, etc.) can be used.

In addition, cholesteric liquid crystal is compatible with various gases, pyrene is compatible with 02 as a test chemical substance,
N,N-dimethylaniline, tris(4,7-diphenyl-1,10-phenanthroline) Ru complex, (CAC
H.

CH,), S or (CβCH* CH*)i N H
Examples of chemical substances to be tested include triphenylmethine neutral red.

Changes in the physical properties of a film containing a chemical substance-sensitive compound as described above are thought to occur in the following manner.

For example, in water-absorbing salts, hydrophilic polymers, hydrophilic gels, etc., the physical properties of the membrane change due to hydration caused by water vapor, or adsorption or absorption of water.

Furthermore, in the case of bromothymol blue and the like, it is thought that some kind of interaction with ammonia, ultimately the formation of a charge transfer complex, etc. occurs, and the physical properties of the film change.

In the case of crown ethers, this is thought to be due to inclusion of ions such as alkali metals and alkaline earth metals.

The bond between the chemical substance-sensitive compound and the test chemical substance may be one that changes the light reflectance of the film, and may be reversible or irreversible. However, from the point of view of repeated use of the sensor, it is preferable that the sensor be reversible.

Further, in the present invention, although only a change in light reflectance may be used as described above, a change in light transmittance may also be used depending on the case.

In addition to changes in reflectance and transmittance using monochromatic light, it is also possible to provide a range of measurement wavelengths and detect changes in the amount of reflected light or transmitted light. In this case, it is preferable that an LED can be used as the light source, and that the amount of light can vary greatly.

In such a case, as described above, it is preferable to use specular reflection.

In the sensor film of a chemical substance sensor as shown in FIG. 1, the dye and the chemical substance sensitive compound may be used in a compatible manner or as a mixture. Further, a part of the chemical substance-sensitive compound may be bound to a dye.

It is preferable for the sensor film to be composed only of dyes and chemical substance-sensitive compounds, but other materials are
A binder such as a self-oxidizing resin such as nitrocellulose, or a thermoplastic resin such as polystyrene or nylon may be included.

The mixing ratio of chemically sensitive compounds to dyes is 0.0
The content is preferably 1 to 40 wt%, preferably 0.1 to 10 wt%.

By setting such a ratio, the bond between the test chemical substance and the chemical substance-sensitive compound can be sufficiently reflected in the change in the physical properties of the film.

It is preferable that the sensor film is a thin film, and a thin film provides a faster response when used as a sensor. The film thickness in this case is 300 to 2.0 OOA, especially 500 to 1.0 OOA.
It is preferable to use OOA.

As shown in FIG. 2, when the sensor film is a laminated film, if the chemical substance sensitive film can be formed only from the chemical substance sensitive compound, it may be formed only from the chemical substance sensitive compound, which is a preferred embodiment.

Specifically, in the case of a humidity sensor, in particular, the above example -
Among them, C) a water-absorbing polymeric anion salt, d>polymer electrolyte, e>hydrophilic polymer, f) hydrophilic gel, etc., yield a coating film with good film properties.

Furthermore, a) sensitivity can be improved by adding a water-absorbing inorganic metal salt.

Further, when ammonia is used as the chemical substance to be tested, poly-2-bala(methacroylaminophenyl)-5-phenyl-1,3-oxazole and the like are also applicable.

Note that other compounds may be formed into films by coating or vapor deposition.

It is also possible to create a sensor film by using chemically sensitive compounds that are the same as the target chemical substance to be tested.

In this case, for example, a polymer chemical-sensitive compound may have a binder function.

Furthermore, binders such as various polymers that do not inhibit the function as a chemical substance-sensitive compound may be used in combination.

The content of the chemically sensitive compound in the chemically sensitive film is preferably 50 to 100 wt%, particularly SO=100 wt%.

With such a content, the physical properties of the sensor film can be sufficiently changed.

The chemical substance sensitive membrane is preferably a thin film in order to speed up the response, and its thickness is 0.05 to 100μ,
In particular, it is preferably 0.1 to 5-.

Further, the pigment film may be composed only of pigment,
A binder such as a self-oxidizing resin such as nitrocellulose, or a thermoplastic resin such as polystyrene or nylon may be included. The pigment content in the pigment film is 60 to 100
It is preferable to set it as wt%, especially 90-100 wt%.

With such a content, changes in film physical properties can be sufficiently reflected in the light reflectance.

Further, the thickness of the dye film may be selected depending on the desired sensitivity, etc., but is usually about 400 to 200 OA.

The material of the base 11 in the present invention is not particularly limited, but it is preferably substantially transparent to the light emitted by the light emitting element 21. This is because detection can be performed from the base 11 side as shown in the figure.

Specifically, glass, hard vinyl chloride, polyethylene terephthalate (PET) polyolefin, polymethyl methacrylate (PMMA), acrylic resin, epoxy resin, polycarbonate resin, polysulfone resin,
Examples include various resins such as polyether sulfone, methylpentene polymer, and bisphenol A-terephthalic acid copolymer.

The base 11 according to the present invention is in the form of a normal plate or film, and its size may be matched to the light-emitting element or the light-receiving element.
Then, a sensor film is formed on at least one surface thereof, usually one main surface thereof.

At this time, if the sensor film is formed on the base and then punched or cut into desired dimensions, it can be easily mass-produced.

Note that a reflective layer may be provided on the side surfaces of the base 11 other than the surface on the light incident side. Such a reflective layer may be formed of aluminum, gold, or the like.

By providing such a reflective layer, detection sensitivity can be increased.

The light emitting element 21 used in the present invention is not particularly limited, but includes light emitting diodes (LEDs), laser diodes (L
D) etc. are preferred.

The light receiving element 22 is also not particularly limited, but is preferably a photodiode, a phototransistor, or the like.

In the present invention, the sensor film is irradiated with light emitted from the light emitting element 21 intermittently.

By performing the irradiation intermittently, the temperature rise of the sensor film can be suppressed. Therefore, the bond between the chemical substance to be tested and the chemical substance-sensitive compound in the sensor film is less likely to be affected by heat, and the measurement accuracy is significantly improved, especially during continuous measurement.

There is no particular restriction on the irradiation time when the irradiation is performed intermittently, but it is preferably set as short as possible within the range in which the reflectance can be measured, for example, about 0.01 to 100 m5ec.

Further, although there is no particular restriction on the irradiation interval, in order to avoid a rise in the temperature of the sensor film, it is preferable to set the irradiation interval as long as possible within a range that satisfies the required measurement interval.

For example, when used as a normal humidity sensor, the irradiation interval is about 0.1 to 10 m5ec.

Note that the effects of the present invention can be achieved if the irradiation is performed intermittently, so there is no particular restriction on the means for performing the intermittent irradiation.

For example, the emitted light may be directly controlled by intermittently energizing the light emitting element.

Intermittent irradiation can also be performed by indirect control such as irradiating continuous emitted light onto the sensor film via a chopper plate or the like.

Furthermore, in any of these methods, the pattern is not limited to alternately repeating irradiation and pauses, and control may be performed to vary the irradiation light intensity. Such cases are also included in the present invention. That is, the reason for performing intermittent irradiation in the present invention is to suppress the temperature rise of the sensor film, so the effects of the present invention can be achieved even in such a case.

Further, in the present invention, it is preferable that the control means 4 including the light emitting power source section and the detection means 5 are provided apart from the sensor film 12. With this configuration, the sensor film 12
temperature rise is further suppressed. Although the distance between the control means or the detection means and the sensor membrane varies depending on the amount of heat generated by each means, it is usually preferably about 0.1 mm or more, and specifically, it may be determined experimentally.

In the embodiments shown in FIGS. 1 and 2, a change in reflectance is detected by a light receiving element 22 provided on the back surface of the base body in close proximity to a light emitting element 21. In this case,
Although the advantages described above are produced, the present invention is not necessarily limited to this embodiment.

For example, the embodiment shown in FIG. 3 may be used. That is, the light emitted by the light emitting element 21 may be obliquely incident on one of the four sides of the base 11, and the light reflectance at this time may be captured by the light receiving element 22. In this case, reflective layers may be provided on three sides of the base 11 excluding the light incident side.

In FIG. 3, detection is performed by one reflection, but as shown in FIG. Sensitivity is improved.

In this case, the number of repetitions is 2 to 8 times, preferably 3 to 5 times.
It should be times.

Further, as shown in FIG. 5, a tapered portion having an angle corresponding to the incident angle and the output angle is formed on the back surface of the base 11,
The light emitting element 21 and the light receiving element 22 may be integrated with the base body 11 in these tapered portions. With this configuration, the device can be made more compact and its robustness can be improved.

Also in this embodiment, the sensor film 12 can be formed on both sides.

Further, as shown in FIG. 6, sensor films 12 are formed on both sides of the base 11, and the wavelengths of the light emitted by the light emitting elements 21 and 23 are made different, and the light reflectance of each wavelength is measured by the light receiving element. It may be configured to detect at 22.24.

With this configuration, detection accuracy can be improved.

In this embodiment, it is also possible to improve the detection accuracy by using one of the films formed on both sides of the substrate 11 as a reference film that does not contain chemical substance-sensitive compounds.

In addition, each sensor membrane 12.12 is a film of a different chemical substance sensitive compound, and two types of test chemicals are detected independently, and when two types of test chemicals are mixed, each substance is detected separately. It is also possible to determine the type from the ratio.

Further, as shown in FIG. 7, a light-emitting light-receiving section 2 is provided, in which a half mirror such as a prism 28, a light-emitting element 21, and a light-receiving element 22 are integrated on the back surface of the base 11 on which the sensor film 12 is formed.
It may be configured to fix 0 and detect reflected light.
This imaging allows the sensor to be made more compact and robust. As described above, in the present invention, it is preferable that the light-emitting element and the light-receiving element are incorporated into one element, and in this case, the -layer can be made more compact.

Further, the base body 11 may not be plate-like or film-like, but may be cylindrical, columnar, etc. For example, as shown in FIG. It is also possible to have a configuration that forms a. In this case, the test fluid containing the test chemical substance may pass through the hollow part. Then, in the same manner as described above, the light emitting/receiving section 20, which is an integrated structure of the light emitting element 21, the light receiving element 22, the prism 28, etc., is fixed to the outer peripheral side surface of the base.

In this case, there are no particular restrictions on the dimensions of the sensor, but it is preferable that the outer diameter of the cylinder is about 1 to 10 mm, the length is about 3 to 20 mm, and the diameter of the hollow part is about 0.5 to 8 mm.

Further, in addition to the illustrated example, a configuration may also be adopted in which a glass fiber is used as the base and a sensor film is formed on the end face of the glass fiber. Furthermore, a plurality of these materials may be bundled together for use. Alternatively, the fibers may be bundled and hardened with resin or the like, and after polishing the end faces, a sensor film may be formed on the end faces.

In these, a light emitting element and a light receiving element are arranged on the end face facing the sensor film.

In addition, as long as the sensor film of the present invention is used, various other embodiments can be adopted.

In the present invention, a breathable protection plate may be provided on the side of the sensor membrane that comes into contact with the test fluid. In this case, an air sandwich structure may be used, or the breathable protection plate may be provided in contact with the membrane surface. .

Further, a filter through which a specific chemical substance can pass may be provided on the membrane surface.

In each of these cases, it is preferable that the light-emitting element and the light-receiving element be arranged and imaged so that they do not come into contact with the test fluid. That is, only the sensor membrane may be exposed to the fluid to be tested, and the light emitting element and the light receiving element may be housed together with the base in a casing or molded.

In order to form a sensor film in the chemical substance sensor of the present invention, a coating liquid containing a dye, a chemical substance sensitive compound, etc. may be prepared according to the configuration of the sensor film, and a coating film may be formed on the substrate.

The coating film may be formed by spin cording, dipping, spraying, or the like.

The solvent is not particularly limited as long as the dye, chemical substance sensitive compound, etc. to be used are soluble therein.

Specifically, keto alcohols (aliphatic keto alcohols, especially diacetone alcohol, acetol, acetoin, acetoethyl alcohol, etc.), R, O-R, -OH[
Here, R is a lower alkyl group (especially having 1 to 5 carbon atoms)
R2 represents a lower alkylene group (particularly having 2 to 5 carbon atoms). ], ketone systems such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, ester systems such as butyl acetate, ethyl acetate, carpitol acetate, butyl carpitol acetate,
Examples include ether systems such as methyl cellosolve and ethyl cellosolve, aromatic systems such as toluene and xylene, halogenated alkyl systems such as cycloethane, water, and alcohol.

In the case of a sensor film having a single layer structure as shown in FIG. 1, when the sensor film contains a dye and a metal halide,
It is also possible to produce it as follows.

That is, the dye has anionic groups (-S01 group, -COO-
If it is a soluble salt having a positive counter ion such as -NH4 to Na, which forms a pair with this anionic group, it can be prepared as described above. After forming the coating film, the metal halide may be introduced into the film at the same time as salt-exchanging the positive counter ions.

This method is suitable for use when the target dye salt is poorly soluble in the coating solvent, and specifically, it is used when the chemical substance-sensitive compound is a metal halide or the like.

Therefore, it is necessary that metal halides such as CaCβ2 exist in this form in the coating film, and it can be used by immersing it in a salt exchange solution and then drying it as is, or after exchanging it, washing it with water or a purified solvent, and then salting it again. It may also be immersed in another salt solution of similar composition to the exchange solution.

Moreover, it is preferable to partially perform salt exchange.

The solution such as C a CQ z used for salt exchange is 1~10w
t%, preferably 2 to 5 wt%.

As the solvent used for the salt exchange solution, the same ones as the coating solvent can be mentioned. However, it is necessary that the dye and the substrate obtained by salt exchange are poorly soluble and can dissolve the salt of the counter ion to be subjected to salt exchange.

Salt exchange may be carried out at a temperature of 0 to 60°C for about 1 to 60 minutes.

The film thickness in this case is 0.05 to 0.1μ, but Ca
It can be appropriately selected depending on the amount of CI2z, etc.

Specifically, the dye used in such a method may be one obtained by forming a salt form of a polymethine dye such as a cyanine dye, an azulenium dye, a biryllium dye, or a thiapyrylium dye.

Among polymethine dyes, cyanine dyes, especially
A cyanine dye having an indolenine ring is preferred.

For details of preferred dyes in this case, see JP-A-58
-194595, 59-202892, 59-
No. 55794, No. 59-55795, No. 59-811
It is described in No. 94, No. 59-83695, etc.

Note that the poorly soluble salt after salt exchange is itself extremely stable against moisture of the test chemical substance.

Further, in the case of forming a laminated sensor membrane as shown in FIG. 2, when a water-absorbing polymeric anion salt is used as the chemical-sensitive compound, the chemical-sensitive membrane can be prepared by the following method.

That is, the chemical substance sensitive compound has an anionic group,
In the case of a soluble salt having a positive counter ion such as Na, NH, etc. that pairs with this anion group, after forming a coating film as described above, the positive counter ion is exchanged with the salt and at the same time the metal It is possible to introduce a halide into the film.

By making such a soluble salt insoluble through salt exchange, the stability of the coating film is improved, such as being extremely stable against moisture of the test chemical substance. Further, by leaving an excess amount of metal halide such as CaCl2z in the coating film, the function as a chemical substance sensitive film can be improved.

Therefore, CaCl2. It is necessary that metal halides such as halides exist in this form, and they can be used either by being immersed in the salt exchange solution and dried as is, or after the exchange and washing with water or a purified solvent, they can be reused in a separate form with the same composition as the salt exchange solution. It may be immersed in a salt solution.

The solution of Ca, CJ2z, etc. used for salt exchange is 1 to 1
It may be 0 wt%, preferably 2 to 5 wt%.

As the solvent used for the salt exchange solution, the same ones as the coating solvent can be mentioned. However, it is necessary that the polymeric anion salt and the substrate obtained by salt exchange are hardly soluble and can dissolve the salt of the counter ion to be subjected to salt exchange.

Salt exchange may be carried out at a temperature of 0 to 60°C for about 1 to 60 minutes.

The film thickness in this case is 0.05 to 0.1-, but CaC
It can be appropriately selected depending on the amount of β3, etc.

In the present invention, the sensor film may be formed by vapor deposition.

That is, it may be carried out according to a known method using a dye and/or a chemical substance-sensitive compound as a vapor deposition source.

Examples of dyes that can be applied at this time include phthalocyanine dyes, naphthalocyanine dyes, squarylium dyes, and croconium dyes.

Further, the installation of the light emitting element and the light receiving element in the present invention may be carried out in accordance with known methods.

In the chemical substance sensor of the present invention, it is possible to control the film thickness of the sensor membrane and the chemical substance sensitive membrane, and by contacting the test fluid containing the test chemical substance, the test chemical substance can be detected depending on the film thickness. can be measured in the range of ppb to 100%.

<Effects of the Invention> The chemical substance sensor of the present invention is used to detect and quantify chemical substances in a test fluid.

In the present invention, the sensor film is intermittently irradiated with light. Therefore, the temperature rise of the sensor film is suppressed, and continuous measurements can be performed with high accuracy.

Furthermore, in the present invention, since the light reflectance is detected using a dye, measurement can be performed from the back surface of the substrate. Since the test chemical substance selectively binds to the chemical-sensitive compound, the dye used has no selectivity. Furthermore, since it can be made into a thin film, the response is fast. Furthermore, the measurable concentration range is wide and the linearity is good.

The element configuration is simple and can be made compact, and its manufacture is also easy.

That is, steps such as sintering and molding are not necessary, and electrodes and the like are also not required, which is advantageous in terms of cost.

Furthermore, since there is no electrical action such as receiving or receiving electrons or applying voltage to the chemically sensitive membrane, there is little deterioration and it can withstand continuous use.

Furthermore, since the chemical substance to be tested and the signal detection element such as a light emitting element or a light receiving element can be made non-contact, durability is also good from this point of view.

The present inventor conducted various experiments to confirm these effects. An example is shown below.

Experimental example 1 A sensor of the embodiment shown in FIG. 1 was assembled.

The chemical substance sensitive membrane at this time was obtained as follows.

On the base PET film (0.1 mm thick), A thin film of 800A was obtained by applying a methanol solution of .

This thin film was immersed in a 5 wt % Ca CA * aqueous solution for 40 seconds for salt exchange. After pulling this up, it was directly dried on a spinner, and further dried at 70° C. for 1 hour.

As a result, a dye film containing the Ca salt of the dye was formed.

On this pigment film, acetylcellulose CSP value 23 (
MJ/m')"", contact angle 70' or less), these two
A wt% cyclohexanone solution was applied to form a sensor film with a thickness of 0.1 μm.

This was then punched out into a disk with a diameter of 7 mm.

An LED that emits light with a wavelength of 950 nm was used as the light emitting element, and a PIN diode was used as the light receiving element, and these were integrated on the back surface of the disk and housed in the casing so that the sensor film was exposed.

When this sensor was used to measure humidity, the R
It was possible to measure water vapor up to the concentration of H. An example of the relationship between the relative humidity and the output voltage of the sensor in this case is shown in Section 9.
As shown in the figure.

This result shows that the measurement concentration range is wide and the linearity is also good.

Next, the light emitting element was operated with a light emission time of 0.1 m5 ec and a light emission interval of 0.9 m5 ec, and continuous measurement was performed for 10 minutes in an atmosphere of 33% RH.

For comparison, humidity was measured in the same manner as above except that the light emitting element was allowed to emit light continuously.

The results are shown in FIG. Note that in FIG. 10, the vertical axis represents the relative value of the output voltage.

As shown in FIG. 10, the change in the sensor output voltage in the case of intermittent irradiation was less than 2%, but in the case of continuous irradiation, the sensor output voltage decreased by 30%.

From this experiment, the effect of the present invention is clear.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views showing embodiments of the chemical substance sensor of the present invention, respectively. FIG. 3, FIG. 4, FIG. 5, FIG. 6, and FIG. 7 are schematic diagrams showing examples of the chemical substance sensor of the present invention, respectively. FIG. 8 is a perspective view showing an embodiment of the chemical substance sensor of the present invention. FIG. 9 is a graph showing the relationship between relative humidity and output voltage when the chemical substance sensor of the present invention is applied to a humidity sensor. FIG. 10 is a graph showing the relationship between irradiation time and output voltage during intermittent irradiation and continuous irradiation. 20... Light emitting/light receiving section 21.23... Light emitting element 22.24... Light receiving element 28... Prism 30... Case 4... Control means 5... Detecting means Applicant T.D. -K Co., Ltd. Representative Patent Attorney Yo Ishii = Patent Attorney Masu 1) Explanation of Tatsuya code 11...Substrate 12...Sensor membrane 121...Chemical substance sensitive membrane 122...Pigment membrane FIG , 1 FIG, 2 FIG, 3 12 FIG, 4 1F I G, 5 E G. Relative degree / % FIG, 6 FIG, 7 2 FIG, 8 1 FIG, 10 Uma (intermediary) Procedure'PFfl official document (spontaneous) November 14, 1990 1, Indication of case 1999 patent application No. 214563 No. 2, Name of the invention Chemical substance sensor 3, Relationship with the case of the person making the amendment Patent applicant name TDT-K Co., Ltd. 4 Agent address: Tenjin Yasaka Kosan, 3-23-1 Yushima, Bunkyo-ku, Tokyo 113 Building 3rd floor R839-0367Fax, 839-0327 "Claims" and 7. Contents of amendment (1) The "Claims" column of the specification will be corrected as shown in the attached sheet. (2) r on page 10, line 2 of the specification (4) r for J
(5) Correct to J. (3) On page 10, lines 6 to 9, "The sensor film contains a dye and a chemical substance-sensitive compound, and the chemical substance-sensitive compound binds to the test chemical substance to cause the sensor film to configured so that the light reflectance changes,
is corrected to "the sensor film is configured such that its light reflectance changes when it combines with a test chemical substance." (4) Insert the following statement between lines 16 and 17 on page 10. (2) The sensor film is configured to contain a dye and a chemical substance-sensitive compound, and the light reflectance of the sensor film changes when the chemical substance-sensitive compound combines with the test chemical substance. The chemical substance sensor described in (1) above.'' (5) r in page 10, line 17 of the same (2) J for r
(3) Correct to J. (6) r(1)J on page 10, line 19 of the same page as r(2)
Correct to J. (7) r (,3) J in the first line of page 11
(4) Correct to J. (8) r (1) J in the 3rd line of page 11 (2)
Correct to J. (9) r in the 5th line of page 1 I (4) J to r(5
) Correct to J. (10) r (3) J in the 6th line of page 11
) Correct to J. (11) Insert "preferably" between "sensor" and "chemical substance" in line 9 of page 11. (12) Insert "preferably" between "on the substrate" and "dye" in the sixth line of page 12. 2. Claims (1) It has a base, a sensor film formed on the base, a light-emitting element, and a light-receiving element, and the sensor film U is activated by combining with an analyte chemical substance. The sensor film is configured so that the reflectance changes, and the test chemical substance is detected and quantified by irradiating the sensor film with light emitted from the light emitting element and detecting the reflectance by the light receiving element. A chemical substance sensor characterized in that the irradiation with the light is performed intermittently. The chemical substance sensor according to claim Z, wherein the sensor film contains a dye and a chemical substance-sensitive compound in a mixed, compatible or combined manner. (1) The chemical sensor according to claim 2, wherein the sensor film is a laminated film of a dye film containing a dye and a chemical sensitive film containing a chemical sensitive compound. (5L) The chemical substance sensor according to claim Δ, wherein in the laminated film, the dye film is present on the substrate side.

Claims (4)

[Claims] (1) It has a base, a sensor film formed on the base, a light emitting element, and a light receiving element, the sensor film contains a dye and a chemical substance sensitive compound, and the chemical substance sensitive compound is coated. The light reflectance of the sensor film is configured to change when combined with a test chemical substance, and the light emitted from the light emitting element is irradiated onto the sensor film, and the reflectance is detected by the light receiving element. 1. A chemical substance sensor configured to detect and quantify a test chemical substance by: a chemical substance sensor configured to detect and quantify a test chemical substance, characterized in that the irradiation with the light is performed intermittently. (2) The chemical substance sensor according to claim 1, wherein the sensor film contains a dye and a chemical substance-sensitive compound in a mixed, compatible or combined manner. (3) The chemical sensor according to claim 1, wherein the sensor film is a laminated film of a dye film containing a dye and a chemical sensitive film containing a chemical sensitive compound. (4) The chemical substance sensor according to claim 3, wherein in the laminated film, the dye film is present on the substrate side.