JP5533378B2 - Frequency measuring device, odor sensor and electronic device equipped with the same - Google Patents

Description

  One embodiment of the present invention relates to a vibrator including an adsorption film, a frequency measurement device including an oscillation circuit connected to the vibrator, and the like.

  When a substance contained in the peripheral medium adheres to the surface of the crystal resonator in a resonance state, there is a phenomenon that the resonance frequency changes according to the attached substance. A technique using this phenomenon is called QCM (Quarts Crystal Microbalance), which is used as a sensor for detecting the presence and amount of molecules contained in a peripheral medium. As an application example of QCM, there is an odor sensor in which an adsorption film that selectively adsorbs specific molecules is formed on the surface of a vibrator. Applications are also being studied as biosensors and gas sensors using DNA hybridization. In the following description, an odor sensor will be mainly described as an example.

  In general, an AT-cut type crystal resonator is used for a QCM device. The AT cut is a substrate cut in a specific orientation with respect to the crystal crystal axis, and since the temperature coefficient change is minimized near the room temperature and excellent in temperature stability, it is widely used not only in the QCM device.

The AT-cut quartz resonator operates in a so-called thickness shear vibration mode in which a front surface and a back surface slide alternately when a voltage is applied between excitation electrodes formed on the front and back surfaces of the substrate. The resonance frequency f0 is inversely proportional to the thickness of the quartz plate sandwiched between the front and back electrodes and generally has the following relationship.
f0 (MHz) = 1670 / crystal plate thickness (μm)

  It is known that the relationship between the adsorbed substance amount ΔM and the frequency change amount Δf of the QCM device using this AT-cut crystal resonator is expressed by the following Sauerbrey equation.

ここで、ｆ０：振動子の共振周波数、ρ：水晶の密度、μ：水晶のせん断弾性定数、Ａ:有効振動面積（略電極面積）である。上式より、水晶振動子の共振周波数ｆ０を高めることにより、感度すなわち吸着物質量ΔＭあたりの周波数変化量Δｆを高められることがわかる。

Here, f0: resonance frequency of the vibrator, ρ: density of crystal, μ: shear elastic constant of crystal, and A: effective vibration area (substantially electrode area). From the above equation, it can be seen that the sensitivity, that is, the frequency change amount Δf per adsorbed substance amount ΔM can be increased by increasing the resonance frequency f0 of the crystal resonator.

  Incidentally, an odor sensor using a QCM device is disclosed in, for example, Japanese Patent Laid-Open No. 63-222248 (Patent Document 1). In the technique disclosed in Example 6 of Patent Document 1, an element in which a bimolecular film made of a dialkylammonium salt and polystyrenesulfonic acid is formed as an adsorption film on the electrode 2 of the AT-cut quartz crystal resonator 1 (FIG. 6). Is used to detect the presence of an odorous substance β-ionone saturated in air as a change in frequency (frequency) (FIG. 9).

  However, in practice, it is impossible to selectively adsorb only the target substance on the adsorption film, and a plurality of substances are adsorbed on the adsorption film. In order to solve this problem, for example, in the technique described in Japanese Patent Application Laid-Open No. 1-244335 (Patent Document 2), the frequency change of a plurality of crystal resonators each having a different type of adsorption film is simultaneously measured to A so-called multi-array method is adopted in which the odor type is identified by pattern analysis of the frequency change ratio between the children.

Japanese Unexamined Patent Publication No. 63-222248 JP-A-1-244335

  In order to increase the odor identification accuracy, it is effective to increase the types of vibrators provided with the adsorption film to be used. It is considered that there are 400,000 types of odorous substances to be detected, and it is not possible to identify such an enormous variety of odorous substances with several (several types) vibrators (QCM) as in the above-described conventional technology. Is possible. The method of identifying the odor type by pattern analysis of the frequency change ratio using a plurality of vibrators provided with different types of adsorption films imitates a living body. There are olfactory cells that react to odors in the nose of living organisms, and it is known that there are about 350 types of olfactory cells in humans and about 1000 types in dogs. Therefore, in order to provide odor discrimination accuracy comparable to that of humans and dogs, it is necessary to provide an odor sensor including hundreds of adsorption films and vibrators. However, an odor sensor having hundreds of adsorption films and vibrators is not practical from the viewpoint of mounting and cost.

  Therefore, in one embodiment of the present invention, an odor sensor capable of reducing the number of adsorption films and vibrators to be mounted while maintaining the odor identification accuracy, and frequency measurement usable for such an odor sensor. An object is to provide a device or the like.

  In order to solve such a problem, the frequency measurement device according to one aspect of the present invention is configured to have a vibrator provided with an adsorption film, a chamber in which the vibrator is disposed, and a gas to flow into the chamber. A first inflow path and a second inflow path. Further, the first inflow path and the second inflow path are configured so that the gas selectively flows through one of the first inflow path and the gas flowing into the chamber through the first inflow path. And the gas flowing through the second inflow path so that the concentration of the substance contained in the gas differs between the gas flowing through the second inflow path and flowing into the chamber It comprises an adsorption / desorption part that adsorbs and / or desorbs a part of the substance contained in

  According to this configuration, the resonance frequency of the vibrator provided with the adsorption film for the gas flowing through the first inflow passage without the adsorption / desorption portion and the gas flowing through the second inflow passage including the adsorption / desorption portion. By measuring the fluctuations of the above, it is possible to obtain information more than the number of vibrators provided for the same gas. Thereby, more frequency information can be obtained without increasing the number of vibrators provided with the adsorption film. As a result, it is possible to increase the identification accuracy of odors and the like in an odor sensor or the like configured with this frequency measuring device without increasing the number of vibrators provided with the adsorption film.

  Moreover, it is preferable that the said adsorption / desorption part is comprised including a cellulose.

  The adsorption / desorption part having such a configuration effectively adsorbs and / or desorbs a substance contained in the gas. Thereby, in the frequency measuring device including such an adsorption / desorption portion, the concentration of the substance contained in the gas flowing through the first inflow passage and the gas flowing through the second inflow passage is appropriately changed and provided. It is possible to provide a frequency measurement device capable of obtaining more preferable information that is equal to or more than the number of vibrators including the adsorption film.

  Further, the adsorption / desorption part is a surface of a fiber mesh material, a cotton-like material in which fibers are intertwined with a gap, a sponge-like material, a bead-like material, or a material having a large number of fins. It may include those coated with a molecular adsorption / desorption liquid, polymer, or inorganic substance.

  The detection device according to one aspect of the present invention further includes the oscillation circuit that is connected to the vibrator and outputs an oscillation signal, and the frequency measurement device configured to be able to measure the frequency of the oscillation signal. And the frequency measured by the frequency measuring device for the gas flowing through the first inflow passage and the frequency measured by the frequency measuring device for the gas flowing through the second inflow passage. And a detection unit configured to be able to detect the substance contained in the gas.

  According to the detection device having such a configuration, the vibrator is targeted for the gas that has passed through the first inflow passage without the adsorption / desorption portion and the gas that has passed through the second inflow passage including the adsorption / desorption portion as described above. By measuring the variation in the frequency of the oscillation signal output from the oscillation circuit connected to, it is possible to obtain more information than the number of transducers provided for the same gas. And it becomes possible to raise the detection accuracy of a substance by detecting the substance contained in gas based on these frequency variation information.

  Moreover, the odor sensor of 1 aspect of this invention is provided with the said frequency measurement apparatus or the said detection apparatus.

  An electronic device of one embodiment of the present invention includes the frequency measurement device or the detection device.

  According to the odor sensor or electronic device having such a configuration, it is possible to provide an odor sensor or electronic device having high odor identification accuracy even with a small number of vibrators.

  The detection method of one embodiment of the present invention includes a step of flowing a gas into a chamber in which a vibrator provided with an adsorption film is circulated through the first inflow path, and the gas is connected to the vibrator. Measuring the frequency of the first oscillation signal output from the generated oscillation circuit, flowing the gas into the chamber through a second inflow path, and outputting the gas from the oscillation circuit Measuring the frequency of the second oscillation signal, and detecting the substance contained in the gas based on the frequency of the first oscillation signal and the frequency of the second oscillation signal. An object contained in the gas between the gas flowing into the chamber through the first inflow path and the gas flowing into the chamber through the second inflow path So that the density varies, wherein the second inflow channel, adsorption and desorption unit for adsorbing and / or desorbing portion of the substance contained in the gas flowing is located.

  According to this method, the gas flowing through the first inflow path without the adsorption / desorption part and the gas flowing through the second inflow path including the adsorption / desorption part are connected to the vibrator having the adsorption film. By measuring the variation in the frequency of the oscillation signal output from the oscillation circuit, it is possible to obtain information more than the number of transducers provided for the same gas. Thereby, more frequency information can be obtained without increasing the number of transducers. As a result, the identification accuracy when odors and the like are identified using this method can be increased without increasing the number of vibrators provided with the adsorption film.

FIG. 3 is a diagram illustrating a configuration example of a measurement device according to the first embodiment. The graph which shows the time change of the frequency of an oscillation signal when targeting the gas containing the orange fragrance | flavor which distribute | circulated the 1st inflow path. The graph which shows the time change of the frequency of an oscillation signal when the gas containing the lavender fragrance which distribute | circulated the 1st inflow path is made into object. The graph which shows the time change of the frequency of an oscillation signal when targeting the gas containing the marjoram fragrance | flavor which distribute | circulated the 1st inflow path. The graph which shows the time change of the frequency of an oscillation signal when targeting the gas containing the orange fragrance | flavor which distribute | circulated the 2nd inflow path. The graph which shows the time change of the frequency of an oscillation signal when the gas containing the lavender fragrance which distribute | circulated the 2nd inflow path is made into object. The graph which shows the time change of the frequency of an oscillation signal when targeting the gas containing the marjoram fragrance which distribute | circulated the 2nd inflow channel. The graph which plotted the peak ratio obtained by twice measurement. FIG. 6 is a diagram illustrating a configuration example of a measurement device according to a second embodiment.

An embodiment according to the present invention will be specifically described according to the following configuration with reference to the drawings. However, the embodiment described below is merely an example of the present invention, and does not limit the technical scope of the present invention. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and the description may be abbreviate | omitted.
1. Definition 2. Embodiment 1
(1) Configuration of detection device (2) Operation of detection device Embodiment 2
4). 4. Features of the present invention Supplement

<1. Definition>
First, terms used in this specification are defined as follows.

  “XX circuit” (XX is an arbitrary word): including, but not limited to, an electric circuit, a physical means for performing the function of the circuit, or a functional means realized by software Is also included. Further, the function of one circuit may be realized by two or more physical or functional means, or the function of two or more circuits may be realized by one physical or functional means.

<2. Embodiment 1>
The configuration and operation of the detection apparatus according to Embodiment 1 of the present invention will be described with reference to FIG.

<(1) Configuration of Detection Device>
FIG. 1 is a diagram illustrating a configuration of a detection device according to the first embodiment. As shown in FIG. 1, the detection device includes an intake pipe 100, a switching valve 110, a first inflow path pipe 120, a second inflow path pipe 130, a chamber 140, an exhaust pump 150, and an exhaust pipe 160. In the chamber 140, crystal resonators 141a and 141b each having an adsorption film are disposed. The detection device further includes oscillation circuits 142a and 142b, frequency counters 143a and 143b, and a detection unit 144. Note that the configuration excluding the detection unit 144 in the detection device is referred to as a frequency measurement device 200.

(Intake pipe 100)
The intake pipe 100 functions as an inflow path for the odor detection target gas, and the gas flowing in from the intake port is supplied to the chamber 140 via the switching valve 110 and the first inflow path pipe 120 or the second inflow path pipe 130. Configured to flow. The amount of gas flowing in from the intake pipe 100 is controlled by an exhaust pump 150 described later.

(Switching valve 110)
The switching valve 110 is configured to selectively send the gas flowing in from the intake pipe 100 to one of the first inflow path pipe 120 and the second inflow path pipe 130. Whether the gas is sent to the first inflow path piping 120 or the second inflow path piping 130 is controlled by a flow path control unit (not shown).

(First inflow passage piping 120)
The first inflow passage piping 120 is configured to allow the gas to flow into the chamber 140 when the gas flows in through the switching valve 110.

(Second inlet pipe 130)
The second inflow passage pipe 130 is configured to cause the gas to flow into the chamber 140 when the gas flows through the switching valve 110. An adsorption / desorption portion 131 is formed in the second inflow passage pipe 130.

(Adsorption / desorption part 131)
The adsorption / desorption portion 131 is configured to be able to adsorb and / or desorb a part of the substance contained in the gas flowing through the second inflow passage pipe 130. For example, the adsorption / desorption part 131 is a material that allows gas to pass easily when installed in a gas flow path and has a large surface area in contact with the gas, and the material itself exhibits molecular adsorption / desorption characteristics. Consists of materials such as cellulose. In place of the above materials, the surface of a fiber mesh material, a material such as cotton in which fibers are intertwined with a gap, a sponge-like material, a bead-like material, or a surface of a material having many fins, You may use what was coated with the molecule | numerator adsorption / desorption liquid, a polymer, or an inorganic substance. Examples of the fiber mesh material include metals such as stainless steel, plastics, and natural fibers such as cellulose. Examples of the above coating materials include polyethylene glycol, nitroterephthalic acid modified polyethylene glycol for molecular adsorption / desorption liquids, or bonded divinylbenzene / ethylene glycol dimethaneacrylate, polydimethylsiloxane, phenylarylene polymer, polydiphenyl / dimethylsiloxane for polymers. , Porous divinylbenzene homopolymer, cyanomethylalkylsiloxane, cyanopropylphenyldimethyl-polysiloxane, cyanopropylphenylmethyl-polysiloxane, cyanopropylmethylallyl-polysiloxane, trifluoropropylmethyl-polysiloxane, trifluoropropylmethyl- Examples thereof include polysiloxane, cyanopropylmethyl-polysiloxane, and inorganic materials such as alumina.

  In this embodiment, as an example, a filter-like member made of cellulose fiber is used. Sufficient air gaps are provided between the fibers constituting the cellulose fiber, and gas can easily pass therethrough. Cellulose fibers have a fiber density and volume comparable to the effective cross-sectional area to the extent that molecules contained in the gas collide with the fibers at least once.

(Chamber 140)
The chamber 140 is configured such that gas flows from the first inflow passage piping 120 and the second inflow passage piping 130. In the chamber 140, crystal resonators 141a and 141b are arranged. In addition, an exhaust pump 150 described later is disposed at the rear stage of the chamber 140, and the gas flowing in from the first inflow passage pipe 120 and the second inflow passage pipe 130 is exhausted to the exhaust pump 150 side.

(Exhaust pump 150 and exhaust pipe 160)
The exhaust pump 150 is configured to be able to control the flow rate of the gas flowing through the detection device by adjusting the amount of gas sucked from the intake port of the detection device. The gas flowing into the exhaust pump 150 is discharged from the exhaust pipe 160.

(Quartz Crystals 141a and 141b)
The crystal resonators 141a and 141b disposed in the chamber 140 are configured to include an adsorption film on the surface. The adsorption film is configured to adsorb a predetermined substance contained in the peripheral medium (gas). In the first embodiment, the adsorption film is configured to adsorb a substance (odorous substance) contained in the gas flowing through the chamber 140. Has been. The resonance frequencies of the crystal resonators 141a and 141b vary depending on the substance attached to the adsorption film, and the frequencies of the oscillation signals output from the oscillation circuits 142a and 142b connected to the crystal resonators 141a and 141b, respectively, are adsorbed. It varies depending on the substance attached to the film. In the first embodiment, a polystyrene resin film is formed on the surface of the crystal resonator 141a and a polymethacrylate resin film is formed on the surface of the crystal resonator 141b as an adsorption film. These polystyrene-based resin films and polymethacrylate-based resin films have characteristics of adsorbing different substances. In addition, the crystal resonators 141a and 141b include a terminal pair, and are connected to the oscillation circuits 142a and 142b through the terminal pair, respectively.

(Oscillation circuits 142a and 142b)
The oscillation circuits 142a and 142b are configured to be connected to the crystal resonators 141a and 141b, respectively. The oscillation circuits 142a and 142b are configured by a Colpitts oscillation circuit, for example, but are not limited thereto. The oscillation circuits 142a and 142b are configured to output oscillation signals to the frequency counters 143a and 143b, respectively. The frequency of these oscillation signals varies depending on the substance attached to the crystal resonators 141a and 141b.

(Frequency counters 143a and 143b)
The frequency counters 143a and 143b are connected to the oscillation circuits 142a and 142b, respectively, and configured to be able to measure the frequencies of the oscillation signals output from the oscillation circuits 142a and 142b, respectively. Specifically, the number of changes in the oscillation signal included in a predetermined time is counted, and the frequency of the oscillation signal is derived based on this count value. For example, the number of changes in the oscillation signal is counted by counting at least one of a rising edge and a falling edge of the signal. However, the frequency counters 143a and 143b do not necessarily need to measure the frequency itself, and an embodiment in which the frequency counter is indirectly measured is also included in the present invention. That is, the frequency counters 143a and 143b may have a function of measuring the signal period of the oscillation signal.

(Detector 144)
The detection unit 144 is configured to be able to detect a substance contained in the gas based on the frequencies measured by the frequency counters 143a and 143b. Specifically, a change in frequency between the frequency of the oscillation signal output from the oscillation circuit 142a and the frequency of the oscillation signal output from the oscillation circuit 142b is measured. In comparison, for example, pattern recognition or the like is performed to detect odorous substances contained in the gas. The database records the type of odor and the like, and the change in frequency corresponding to the odor and the like.

<(2) Operation of Detection Device>
Next, an operation example of the detection apparatus according to the first embodiment will be described with reference to FIGS. 2 to 7, the arrows in the drawings indicate the time when the odor source is brought closer to the intake port of the intake pipe 100.

(Measurement 1)
First, the flow path control unit (not shown) places the switching valve 110 in a state in which the intake pipe 100 and the first inflow path pipe 120 are connected. In this state, the exhaust pump 150 is operated with the odor source away from the intake port, and a gas containing no odorous substance (odorant molecule) is caused to flow into the chamber 140. This stabilizes the frequency measured by the frequency counters 143a and 143b.

  When the frequency measured by the frequency counters 143a and 143b is stabilized, an odor source is brought close to the intake port, and a gas containing an odor substance is caused to flow into the chamber 140. Then, the odorous substance contained in this gas adheres to the adsorption film of the crystal oscillators 141a and 141b, and the frequency measured by the frequency counters 143a and 143b decreases. The frequency measured by the frequency counters 143a and 143b decreases until the odorant concentration between the gas in the chamber 140 and the adsorption film reaches an equilibrium state, and then stabilizes.

  Thereafter, when the odor source is quickly moved away from the intake port, the gas not containing the odor substance is sucked and the odor substance concentration of the gas in the chamber 140 is lowered. Then, since the odorant concentration of the adsorption film becomes higher than the odorant concentration of the surrounding gas, the odorant substance of the adsorption film starts to desorb from the adsorption film. Thereby, the frequency measured by the frequency counters 143a and 143b increases.

  FIGS. 2 to 4 show the time variation of the frequency measured by the frequency counters 143a and 143b when the orange flavor, the lavender flavor, and the marjoram flavor are used as the odor source and the odor source is actually inhaled in the above procedure. It is a graph which shows. In these graphs, the graph described in the upper row shows the frequency of the oscillation signal of the oscillation circuit 142a connected to the quartz crystal resonator 141a having the polystyrene resin membrane, and the graph shown in the lower row shows the polymethacrylate resin membrane. Each time change of the frequency of the oscillation signal of the oscillation circuit 142b connected to the crystal oscillator 141b provided is shown. The vertical axis of the graph indicates the frequency, but this does not indicate the absolute value of the frequency but indicates the fluctuation of the frequency. The frequency shown in the upper part and the frequency shown in the lower part are in a steady state. It shows almost the same frequency. Since the odor source is moved away before the adsorption of the odorous substance on the adsorption film reaches an equilibrium state, the measured frequency has a peak shape as shown in FIGS.

  In the case of the configuration using two crystal resonators as in the first embodiment, the ratio (peak ratio) of the response peak values, which are the peak values of the frequency change between the crystal resonators 141a and 141b, is the kind of odorous substance. It becomes an index to identify. This peak ratio is determined by (frequency of oscillation signal of oscillation circuit 142a) / (frequency of oscillation signal of oscillation circuit 142b). For example, when two odor sources are identified, if the peak ratios measured by the odor substances contained in these odor sources are significantly different from each other, they are less affected by noise and can detect odor substances with high accuracy. It becomes. However, in the measurement results shown in FIGS. 2 to 4, the respective peak ratios are 1.11 for the gas containing the orange fragrance, 0.90 for the gas containing the lavender fragrance, and 1.21 for the gas containing the marjoram fragrance. , Are close to each other. Therefore, it cannot be said that the detection accuracy of an odorous substance is high.

  In addition, since each fragrance | flavor used here contains the some odorous substance, the mixed gas containing several types of odorous substances is exposed to the quartz oscillator provided with an adsorption film.

(Measurement 2)
Next, the flow path control unit (not shown) places the switching valve 110 in a state of connecting the intake pipe 100 and the second inflow path pipe 130. In this state, the exhaust pump 150 is operated in a state where the odor source is away from the intake port, and a gas containing no odor substance is caused to flow into the chamber 140. This stabilizes the frequency measured by the frequency counters 143a and 143b.

  When the frequency measured by the frequency counters 143a and 143b is stabilized, an odor source is brought close to the intake port, and a gas containing an odor substance is caused to flow into the chamber 140. Here, since the second inflow passage pipe 130 is provided with the adsorption / desorption portion 131, a part of the substance contained in the gas flowing in from the intake port is adsorbed and / or desorbed by the adsorption / desorption portion 131. After that, it flows into the chamber 140. The odorous substance contained in the gas that has passed through the adsorption / desorption portion 131 adheres to the adsorption films of the crystal resonators 141a and 141b, and the frequency measured by the frequency counters 143a and 143b decreases. The frequency measured by the frequency counters 143a and 143b decreases until the odorant concentration between the gas in the chamber 140 and the adsorption film reaches an equilibrium state, and then stabilizes.

  Thereafter, when the odor source is quickly moved away from the intake port, the gas not containing the odor substance is sucked and the odor substance concentration of the gas in the chamber 140 is lowered. Then, since the odorant concentration of the adsorption film becomes higher than the odorant concentration of the surrounding gas, the odorant substance of the adsorption film starts to desorb from the adsorption film. Thereby, the frequency measured by the frequency counters 143a and 143b increases.

  FIGS. 5 to 7 show the time change of the frequency measured by the frequency counters 143a and 143b when the orange flavor, the lavender flavor, and the marjoram flavor are used as the odor source and the odor source is actually inhaled in the above procedure. It is a graph which shows. In these graphs, the graph described in the upper row shows the frequency of the oscillation signal of the oscillation circuit 142a connected to the quartz crystal resonator 141a having the polystyrene resin membrane, and the graph shown in the lower row shows the polymethacrylate resin membrane. Each time change of the frequency of the oscillation signal of the oscillation circuit 142b connected to the crystal oscillator 141b provided is shown. 2 to 4, the vertical axis of the graphs shown in FIGS. 5 to 7 indicates the frequency, but this does not indicate the absolute value of the frequency but indicates the fluctuation of the frequency. The frequency shown and the frequency shown in the lower part show substantially the same frequency in the steady state. Since the odor source is moved away before the adsorption of the odorous substance to the adsorption film reaches an equilibrium state, the measured frequency has a peak shape as shown in FIGS.

  Here, the peak ratio in the above measurement is 2.50 for the gas containing the orange fragrance, 1.23 for the gas containing the lavender fragrance, and 2.10 for the gas containing the marjoram fragrance. It can be seen that these peak ratios are completely different from those in the case of the gas flowing through the first inflow passage pipe 120 shown in FIGS.

(Identification based on measurement)
As described above, even when substances contained in a gas containing the same fragrance are measured using a crystal resonator having the same adsorption film, different peak ratios can be obtained depending on the presence / absence of the adsorption / desorption part 131. FIG. 8 is a graph showing the peak ratio in the measurement 1 on the horizontal axis and the peak ratio in the measurement 2 on the vertical axis, assuming that each has a measurement variation of ± 0.1. In FIG. 8, the measurement results in the gas containing the orange flavor, the lavender flavor, and the marjoram flavor are shown as 300, 310, and 320, respectively. As shown in FIG. 8, only the measurement 1 has a portion where the peak ratios of the measurement results of the gas (300) containing the orange fragrance and the gas (320) containing the marjoram fragrance overlap. From the above data, it can be seen that the peak ratio in the measurement result of the gas (300) containing the orange flavor and the gas (320) containing the marjoram flavor does not overlap. That is, it can be said that the identification accuracy of the substance contained in the gas is improved.

  In order to improve the identification accuracy, it is necessary that the data ranges (clusters) of each other are well separated without overlapping. Increasing the number of data dimensions is effective in separating clusters while allowing variation. In the odor sensor, the number of dimensions is increased by increasing the number of crystal resonators. However, in the detection device of the first embodiment, the number of data dimensions can be increased without increasing the number of crystal resonators. It becomes.

<(3) Features of Embodiment 1>
It can be said that the detection apparatus shown in the first embodiment has the following characteristics.

  In the frequency measuring device included in the detection device according to the first embodiment, gas is selectively circulated through one of the first inflow passage pipe 120 and the second inflow passage pipe 130, and the second inflow passage is provided. An adsorption / desorption portion 131 that adsorbs and / or desorbs part of a substance contained in the flowing gas is disposed in the pipe 130. As a result, the concentration of the substance contained in the gas between the gas flowing through the first inlet channel 120 and flowing into the chamber 140 and the gas flowing through the second inlet channel 130 and flowing into the chamber 140 is reduced. Come different.

  According to the frequency measuring device having such a configuration, the gas flowing through the first inflow passage pipe 120 having no adsorption / desorption portion and the gas flowing through the second inflow passage piping 130 including the adsorption / desorption portion 131 are targeted. By measuring fluctuations in the resonance frequency of the crystal resonators 141a and 141b including the adsorption film, it is possible to obtain information more than the number of crystal resonators provided for the same gas. Thereby, more frequency information can be obtained without increasing the number of crystal units. As a result, the identification accuracy of odors and the like in an odor sensor or the like configured with this frequency measuring device can be increased without increasing the number of crystal units.

  Moreover, it is preferable that the adsorption / desorption part 131 is comprised including a cellulose.

  The adsorption / desorption part 131 configured to contain cellulose effectively adsorbs and / or desorbs a substance contained in a gas. Thereby, in the frequency measurement device including the adsorption / desorption portion 131, the concentration of the substance contained in the gas flowing through the first inflow passage piping 120 and the gas flowing through the second inflow passage piping 130 is appropriately changed, It is possible to provide a frequency measurement device capable of obtaining more preferable information that is equal to or more than the number of quartz resonators provided with the provided adsorption films.

  Furthermore, in the detection apparatus of the first embodiment, the gas is determined based on the frequency measured for the gas flowing through the first inflow passage piping 120 and the frequency measured for the gas flowing through the second inflow passage piping 130. The detection part 144 comprised so that detection of the contained substance was possible is provided.

  According to the detection device having such a configuration, the gas that has passed through the first inflow passage pipe 120 having no adsorption / desorption portion as described above and the gas that has circulated through the second inflow passage piping 130 including the adsorption / desorption portion 131 are targeted. By measuring the fluctuation of the frequency of the oscillation signal by the frequency counters 143a and 143b, it is possible to obtain information more than the number of vibrators provided for the same gas. And it becomes possible to raise the detection accuracy of a substance by detecting the substance contained in gas based on these frequency variation information.

  In addition, the frequency measurement device or the detection device of the first embodiment can be applied to an odor sensor or an electronic device.

  According to the odor sensor or electronic device having such a configuration, it is possible to provide an odor sensor or electronic device having high odor discrimination accuracy despite a small number of vibrators.

  In the first embodiment, a detection method including the following steps is shown. That is, (1) a step of flowing a gas into the chamber 140 in which the crystal resonators 141a and 141b provided with the adsorption film are circulated through the first inflow passage pipe 120, and (2) the crystal resonator with respect to this gas Measuring the frequency of the first oscillation signal output from the oscillation circuits 142a and 142b connected to 141a and 141b. Further, (3) a step of flowing gas into the chamber 140 through the second inflow passage pipe 130, and (4) measuring the frequency of the second oscillation signal output from the oscillation circuits 142a and 142b for this gas. Including the step of. And (5) detecting a substance contained in the gas based on the frequency of the first oscillation signal and the frequency of the second oscillation signal. At this time, the substance contained in the gas between the gas flowing into the chamber 140 through the first inlet pipe 120 and the gas flowing into the chamber 140 through the second inlet pipe 130. An adsorption / desorption portion 131 is arranged in the second inflow passage pipe 130 so that the concentrations of the two are different.

  According to this method, the quartz crystal resonator including the adsorption film for the gas flowing through the first inflow passage pipe 120 having no adsorption / desorption portion and the gas flowing through the second inflow passage piping 130 including the adsorption / desorption portion. By measuring fluctuations in the frequency of the oscillation signals output from the oscillation circuits 142a and 142b connected to the 141a and 141b, it is possible to obtain information more than the number of transducers provided for the same gas. Thereby, more frequency information can be obtained without increasing the number of crystal resonators. As a result, it is possible to increase the identification accuracy when identifying odors and the like using this method without increasing the number of crystal units.

  In the above detection method, the steps (1) and (2) may be interchanged with the steps (3) and (4).

<3. Second Embodiment>
Next, the configuration of the detection apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. In addition, since the detection apparatus of this Embodiment 2 is equipped with the structure similar to the detection apparatus of Embodiment 1 in many points, only the structure peculiar to this Embodiment 2 is demonstrated concretely in the following description. The operation of the detection apparatus is the same as that of the first embodiment, and a description thereof is omitted.

  FIG. 9 is a diagram illustrating a configuration of the detection device according to the second embodiment. As shown in FIG. 9, the detection device includes a first inflow passage pipe 120, a second inflow passage pipe 130, a chamber 140, an exhaust pump 150, and an exhaust pipe 160. In the chamber 140, crystal resonators 141a and 141b each having an adsorption film are disposed. The detection device includes oscillation circuits 142a and 142b, frequency counters 143a and 143b, and a detection unit 144. Further, the detection device includes a flow control valve 180 in the first inflow passage pipe 120, a flow control valve 181 in the second inflow passage pipe 130, and a flow control unit 170 that controls these flow control valves 180 and 181. Prepare. The second embodiment is different from the first embodiment in that the flow control valves 180 and 181 and the flow control unit 170 are provided.

  In the detection device of the second embodiment, the flow control unit 170 and the flow control valves 180 and 181 function as the switching valve 110 in the first embodiment. That is, the flow control unit 170 and the flow control valves 180 and 181 are configured so that gas can be selectively circulated through one of the first inflow passage piping 120 and the second inflow passage piping 130.

  The detection apparatus of the second embodiment has the same effect as that of the first embodiment. However, the detection device of the second embodiment includes flow control valves 180 and 181 having a simple mechanical structure as compared with the switching valve 110 shown in the first embodiment, and the flow control valves 180 and 181 are flow controlled. Controlled by the unit 170. Therefore, it is possible to provide a detection device that is less prone to mechanical problems.

<5. Supplement>
In the frequency measurement device of each of the above embodiments, the crystal resonators 141a and 141b are used, but a resonator other than the crystal resonator may be used.

  Moreover, although the example provided with two crystal resonators was demonstrated in the frequency measuring device of each said embodiment, you may arrange | position more crystal resonators.

  Further, the adsorption / desorption portion 131 is not limited to a filter-like configuration made of cellulose fiber. For example, a filter-like structure using another material may be used, and the filter-like structure may not be used. As a material other than the filter configuration, for example, a material that adsorbs and / or desorbs a predetermined substance may be disposed on the inner side surface of the second inflow passage pipe 130.

  Moreover, in each said embodiment, although two inflow path piping, the 1st flow path piping 120 and the 2nd inflow path piping 130, was arrange | positioned, it is good also as a structure provided with an additional inflow path piping. In this case, it is preferable that the third inflow path pipe is provided with an adsorption / desorption part having adsorption and / or desorption characteristics different from the adsorption / desorption part 131 provided in the second inflow path pipe 130.

  Moreover, it is good also as a structure provided with an adsorption / desorption part in both the 1st inflow path piping 120 and the 2nd inflow path piping 130. FIG. In this case, similarly to the above, it is preferable that the adsorption and / or desorption characteristics of the two adsorption / desorption portions are different.

  Further, in the embodiment, the quartz crystal having an adsorption film for the gas flowing through the first inflow passage pipe 120 having no adsorption / desorption portion and the gas flowing through the second inflow passage piping 130 including the adsorption / desorption portion 131 are targeted. Variations in the resonance frequency of the vibrators 141a and 141b are measured, and a substance is detected based on both of these frequency variations. However, the present invention is not necessarily limited to this form. For example, in the above two measurement results, a method of selectively using a measurement result more suitable for detection of a substance contained in a gas can be considered, and this method is also included in the present invention. Is.

DESCRIPTION OF SYMBOLS 100 ... Intake piping, 110 ... Switching valve, 120 ... 1st inflow passage piping, 130 ... 2nd inflow passage piping, 131 ... Adsorption / desorption part, 140 ... Chamber, 141a, 141b ... Quartz crystal oscillator 142a, 142b, oscillation circuit, 143a, frequency counter, 144, detection unit, 150, exhaust pump, 160, exhaust pipe, 170, flow control unit, 180, 181, flow control valve, 200 ...... Frequency measuring device

Claims (7)

An oscillator with an adsorption film;
A chamber in which the vibrator is disposed;
A first inflow path and a second inflow path configured to allow gas to flow into the chamber;
The first inflow path and the second inflow path are configured so that the gas is selectively circulated through one of them,
The concentration of the substance contained in the gas between the gas flowing into the chamber through the first inflow path and the gas flowing into the chamber through the second inflow path The second inflow path is configured to include an adsorption / desorption portion that adsorbs and / or desorbs a part of the substance contained in the flowing gas.
Frequency measuring device. The adsorption / desorption part is configured to contain cellulose.
The frequency measuring device according to claim 1.   The adsorption / desorption part absorbs the surface of a fiber mesh-like material, a cotton-like material in which fibers are entangled with a gap, a sponge-like material, a bead-like material, or a material having a large number of fins. The frequency measuring device according to claim 1, comprising a coating with a desorption liquid, a polymer, or an inorganic substance. An oscillation circuit connected to the vibrator and outputting an oscillation signal;
A frequency measuring device according to any one of claims 1 to 3, further comprising a frequency measuring device configured to be able to measure the frequency of the oscillation signal.
Based on the frequency measured by the frequency measuring device for the gas flowing through the first inflow passage and the frequency measured by the frequency measuring device for the gas flowing through the second inflow passage, A detector configured to detect a substance contained in the gas;
A detection device comprising:   An odor sensor comprising the frequency measurement device according to any one of claims 1 to 3 or the detection device according to claim 4.   An electronic apparatus comprising the frequency measurement device according to any one of claims 1 to 3 or the detection device according to claim 4. Flowing the gas into the chamber in which the vibrator having the adsorption film is disposed by circulating the first inflow path;
Measuring the frequency of a first oscillation signal output from an oscillation circuit connected to the vibrator for the gas;
Flowing the second inflow path to flow the gas into the chamber;
Measuring the frequency of the second oscillation signal output from the oscillation circuit for the gas;
Detecting a substance contained in the gas based on the frequency of the first oscillation signal and the frequency of the second oscillation signal,
The concentration of the substance contained in the gas between the gas flowing into the chamber through the first inflow path and the gas flowing into the chamber through the second inflow path Are different from each other, an adsorption / desorption part that adsorbs and / or desorbs a part of the substance contained in the flowing gas is arranged in the second inflow path,
Detection method.

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