JP2015040793A - Gas sensor - Google Patents

Abstract

A gas sensor that does not require a separate adsorbing member is provided. A beam member having at least one end fixed to resonate and vibrate with a vibration source, a support portion that supports the beam member, and a vibration detection element that is fixed to the beam member and detects vibration of the beam member. In this gas sensor, the beam member is formed of a polymer material, and at least a part of the surface of the beam member is an adsorption region that adsorbs a volatile organic compound. The vibration source includes both the case where the gas sensor is provided and the case where the vibration source is provided separately from the gas sensor. [Selection] Figure 1

Description

  The present invention relates to a gas sensor.

  As a sensor for detecting volatile organic compounds, the vibrator is vibrated in a gas containing molecules of volatile organic compounds, and the mass change of the vibrator when the molecules are adsorbed on the surface of the vibrator is measured. Alternatively, a vibration type sensor that detects a change in resonance frequency is used.

  Vibration sensors are widely used because they are excellent in terms of low power consumption and miniaturization. As a material of the vibrator, a material having a high Young's modulus such as silicon or quartz is used. For example, a configuration disclosed in Patent Document 1 below is known as such a sensor. In this configuration, a vibrator that increases the amount of change in the resonance frequency with respect to the deformation of the beam member is used. The gas sensor includes a first beam member and a second beam member that are coupled to each other and driven to vibrate. The first beam member is provided with a gas sensitive film whose shape can be changed. The first beam member is deformed in a different manner from the second beam member due to the deformation of the gas sensitive film. In the configuration described in Patent Document 1, silicon is used as the material of the beam body of the first beam member and the second beam member (see, for example, paragraphs [0021]-[0022] of Patent Document 1).

JP 2012-83338 A

  In the said patent document 1, the silicon | silicone which does not adsorb | suck a volatile organic compound is used for a beam member. For this reason, an adsorbing member must be provided in addition to the beam member (silicon).

  The present invention has been made in view of the above, and an object of the present invention is to provide a gas sensor that does not require a separate adsorbing member.

  In order to solve the above-described problems and achieve the object, a gas sensor according to the present invention includes a beam member that is fixed at least at one end and resonates and vibrates with a vibration source, a support portion that supports the beam member, and a beam member. A gas sensor comprising a vibration detection element that is fixed to a beam and detects a vibration of a beam member, wherein the beam member is formed of a polymer material, and at least a part of the surface of the beam member is adsorbed to adsorb a volatile organic compound. It is a region.

  A gas sensor according to another aspect of the present invention includes a beam member having at least one end fixed thereto, a support unit that supports the beam member, a drive unit that applies vibration so that the beam member resonates, and a beam member. A gas sensor comprising a vibration detection element that is fixed and detects vibration of a beam member, wherein the beam member is formed of a polymer material, and at least a part of the surface of the beam member adsorbs a volatile organic compound It is characterized by.

  A gas sensor according to another aspect of the present invention includes a beam member having at least one end fixed, resonating and vibrating with an external vibration source, a support portion supporting the beam member, and a beam member fixed to the beam member. A gas sensor comprising a vibration detecting element for detecting vibration of a beam, wherein the beam member is formed of a polymer material, and at least a part of the surface of the beam member is an adsorption region that adsorbs a volatile organic compound. And

  The present invention has an effect of providing a gas sensor that does not require a separate adsorbing member.

It is a figure which shows the isometric view structure of the gas sensor which concerns on 1st Embodiment of this invention. It is a figure which shows the isometric view structure of the gas sensor which concerns on 2nd Embodiment of this invention. It is a figure which shows the isometric view structure of the gas sensor which concerns on 3rd Embodiment of this invention. It is a figure which shows the isometric view structure of the gas sensor which concerns on 4th Embodiment of this invention. It is a figure which shows the isometric view structure of the gas sensor which concerns on 5th Embodiment of this invention.

  The effect by the structure of the gas sensor of this embodiment is demonstrated. In addition, this invention is not limited by this embodiment. That is, in describing the embodiment, a lot of specific details are included for the purpose of illustration, but various variations and modifications may be added to these details without exceeding the scope of the present invention. Accordingly, the exemplary embodiments of the present invention described below are set forth without loss of generality or limitation to the claimed invention.

(First embodiment)
FIG. 1 is a diagram illustrating a perspective configuration of a gas sensor 100 according to the first embodiment. First, the configuration will be described.
The gas sensor 100 according to the present embodiment includes at least one end fixed, a beam member 11 that resonates and vibrates with a vibration source, a support portion 13 that supports the beam member 11, and a beam member 11 that is fixed to the beam member 11. A gas sensor 100 including a vibration detection element 12 for detecting vibration, in which a beam member 11 is formed of a polymer material, and at least a part of the surface of the beam member 11 is adsorbed with an adsorption region 10 that adsorbs a volatile organic compound. It is the structure to do.

  Further, the configuration will be specifically described. One end of the beam member 11 is supported by the support portion 13. A vibration detection element 12 is provided across the beam member 11 and the support portion 13. The vibration detection element 12 is provided on the upper surface of the beam member 11 by laminating a piezoelectric material such as PZT or polyvinylidene fluoride (PVDF).

  One end of the beam member 11 made of a polymer material that adsorbs a volatile organic compound is fixed to the support portion 13 as described above. The support unit 13 is connected to the drive unit 14. Therefore, the gas sensor 100 of the present embodiment is configured such that the beam member 11 vibrates in resonance with the vibration applied by the driving unit 14.

  Furthermore, since the vibration detection element 12 is laminated on the beam member 11 in the gas sensor 100 of the present embodiment, the vibration detection element 12 detects the vibration of the beam member 11. Although not shown, wiring for detecting an electrical signal from the vibration detection element 12 is electrically connected to the signal processing unit.

  Next, the driving method of this embodiment will be described. As shown in FIG. 1, one end of the beam member 11 is fixed to the support portion 13. The support unit 13 is connected to the drive unit 14. When the drive unit 14 vibrates, the beam member 11 vibrates at a resonance frequency.

  When the beam member 11 is exposed to the volatile organic compound, the volatile organic compound is adsorbed to a part of the beam member 11. For this reason, the mass of the beam member 11 increases. Therefore, the resonance frequency of the beam member 11 decreases due to the influence of the mass of the volatile organic compound adsorbed on the beam member 11.

  Further, as shown in FIG. 1, a vibration detection element 12 is formed on the upper surface of the beam member 11. When the beam member 11 vibrates, stress is transmitted to the vibration detecting element 12. Since the vibration detecting element 12 is a material having piezoelectricity, a voltage is generated by an applied stress. Therefore, the resonance frequency of the beam member 11 can be detected by measuring the voltage of the vibration detection element 12.

  For example, the length of the beam member 11 is 1000 μm to 2500 μm, the width is 200 μm to 500 μm, and the height is 20 μm to 250 μm.

  Next, the operation of this embodiment will be described. The beam member 11 of the gas sensor 100 of this embodiment vibrates in resonance with the vibration applied by the drive unit 14. The vibration detection element 12 detects the vibration of the beam member 11. When the beam member 11 adsorbs a volatile organic compound while the driving unit 14 vibrates the beam member 11 at the resonance frequency, the mass of the beam member 11 increases. For this reason, the resonant frequency of the beam member 11 falls. By detecting the change in the resonance frequency by the vibration detecting element 12, the concentration of the volatile organic compound can be measured.

Further, the beam member 11 of the gas sensor 100 of the present embodiment is formed of a polymer material having a low Young's modulus. In the present embodiment, preferably, the Young's modulus of the polymer material is 1 GPa or more and 10 GPa or less. In general, in a gas sensor that detects a volatile organic compound, the sensitivity and the resonance frequency are in a proportional relationship. The resonance frequency of the beam member 11 is proportional to the square root of the Young's modulus and inversely proportional to the square of the length of the beam member 11.
The Young's modulus of the polymer material is lower than the Young's modulus of the conventional silicon. For this reason, in this embodiment, by setting in the range of the above-mentioned Young's modulus, it can reduce in size compared with the beam member of the same resonance frequency.

  As a reference, the Young's modulus of silicon is approximately 70 GPa to 170 GPa although it varies depending on the crystal orientation.

To explain further, in the cantilever beam, the resonance frequency increases as the vibration mode becomes higher. Further, it is known that in a vibration type gas sensor, the detection sensitivity is higher when the resonance frequency is higher, that is, the sensitivity is proportional to the resonance frequency.
Therefore, in order to obtain high sensor performance in a cantilever vibration type gas sensor, sensing corresponding to a higher-order vibration mode is desirable.

  In this embodiment, it is desirable to use, for example, polyethylene terephthalate (PET), polycarbonate, or polymethyl methacrylate resin (PMMA) as the polymer material.

  As described above, the gas sensor 100 of the present embodiment uses a polymer material instead of silicon as the material of the beam member 11 in the vibrator. The beam member 11 made of a polymer material adsorbs volatile organic compounds. For this reason, compared with the conventional structure which needs to provide an adsorption member separately, the beam member 11 can be utilized effectively. As a result, there is an extraordinary effect that the detection function of the gas sensor 100 can be further improved.

  Further, by using a material having a low Young's modulus for the beam member 11, the gas sensor 100 can be reduced in size.

  Next, a modified example will be described. As shown in FIG. 1, in the present embodiment, the support portion 13 is connected to the drive portion 14. However, the present invention is not limited to this, and may be configured to be attached to a vibrating device such as a mechanical device. This configuration will be described later. A plurality of fine holes may be formed in a partial region of the beam member 11. Or you may form a fine unevenness | corrugation in the one part area | region of a beam member.

(Second Embodiment)
Next, the gas sensor of 2nd Embodiment is demonstrated.
FIG. 2 is a perspective view showing the gas sensor 200 of the present embodiment. As shown in FIG. 2, an adsorbing member 25 that is fixed to a part of the beam member 21 and adsorbs a volatile organic compound is provided. More specifically, the gas sensor 200 includes a beam member 21, a vibration detection element 22, a support portion 23, and an adsorption member 25. The vibration detection element 22 is provided on the upper surface of the beam member 21 by laminating a piezoelectric material such as PZT or PVDF.

  The adsorbing member 25 that adsorbs a volatile organic compound is provided on the upper surface of the beam member 21 by forming a film that adsorbs a volatile organic compound such as polybutadiene (PBD), titanium oxide, or zinc oxide. The adsorption member 25 and the beam member 21 are formed of different materials. One end of the beam member 21 made of a polymer material that adsorbs a volatile organic compound is fixed to the support portion 23.

  The support part 23 is connected to the drive part 24. Accordingly, the gas sensor 200 is configured to vibrate in resonance with the vibration applied by the drive unit 24 of the beam member 21 on which the adsorption member 25 is formed. Furthermore, in the gas sensor 200 of the present embodiment, the vibration detection element 22 is laminated on the beam member 21. Therefore, the vibration of the beam member 21 is detected by the vibration detection element 22. Although not shown, wiring for detecting an electrical signal from the vibration detection element 22 is electrically connected to the signal processing unit.

Next, the driving method of this embodiment will be described.
As shown in FIG. 2, one end of the beam member 21 is fixed to the support portion 23. The support part 23 is connected to the drive part 24. When the drive unit 24 vibrates, the beam member 21 vibrates at a resonance frequency. When the beam member 21 is exposed to the volatile organic compound, the volatile organic compound is adsorbed to a part of the beam member 21. For this reason, the mass of the beam member 21 increases.

  Further, when the adsorbing member 25 is exposed to the volatile organic compound, the volatile organic compound is adsorbed to a part of the adsorbing member 25. Thereby, the mass of the beam member 21 increases. As a result, the resonance frequency of the beam member 21 decreases due to the mass of the volatile organic compound adsorbed on the beam member 21 or the adsorption member 25.

  Further, as shown in FIG. 2, a vibration detection element 22 is formed on the upper surface of the beam member 21. When the beam member 21 vibrates, stress is transmitted to the vibration detecting element 22. Since the vibration detecting element 22 is a material having piezoelectricity, a voltage is generated by an applied stress. Therefore, the resonance frequency of the beam member 21 can be detected by measuring the voltage of the vibration detection element 22.

  Next, the operation of this embodiment will be described. The beam member 21 of the gas sensor 200 of this embodiment vibrates in resonance with the vibration applied by the drive unit 24. The vibration detection element 22 detects the vibration of the beam member 21. When at least one of the beam member 21 and the adsorbing member 25 adsorbs the volatile organic compound when the driving unit 24 vibrates the beam member 21 at the resonance frequency, the mass of the beam member 21 increases. Thereby, the resonant frequency of the beam member 21 falls. By detecting the change in the resonance frequency with the vibration detection element 22, the concentration of the volatile organic compound can be measured.

  Further, the beam member 21 of the gas sensor 200 of the present embodiment is formed of a polymer material having a low Young's modulus. In general, in a gas sensor that detects a volatile organic compound, the sensitivity and the resonance frequency are in a proportional relationship. The resonance frequency of the beam member 21 is proportional to the square root of the Young's modulus and inversely proportional to the square of the length of the beam member. The Young's modulus of the polymer material is lower than that of the conventional silicon. Thereby, the beam member of the same resonance frequency can be reduced in size.

  As described above, the gas sensor 200 of the present embodiment uses a polymer material instead of silicon as the material of the beam member 21 in the vibrator. The beam member 21 made of a polymer material adsorbs volatile organic compounds. The adsorbing member 25 fixed to the beam member 21 adsorbs a volatile organic compound different from that of the beam member 21. Thereby, there exists an effect that two types of volatile organic compounds can be detected with one sensor.

Further, by setting the material of the beam member 21 to a material having a low Young's modulus, for example, 1 GPa or more and 10 GPa or less, the gas sensor 200 can be reduced in size.
As shown in FIG. 2, in the present embodiment, the support portion 23 is connected to the drive portion 24. However, the present invention is not limited to this, and may be configured to be attached to a vibrating device such as a mechanical device, as will be described later.

(Third embodiment)
Next, the gas sensor 300 of 3rd Embodiment is demonstrated. FIG. 3 is a perspective view of the gas sensor 300. As shown in FIG. 3, the gas sensor 300 includes at least two adsorbing members that are fixed to a part of the beam member 31 and adsorb volatile organic compounds. More specifically, the gas sensor 300 includes a beam member 31, a vibration detection element 32, a support portion 33, a first adsorption member 35, and a second adsorption member 36.

  The vibration detection element 32 is provided on the upper surface of the beam member 31 by laminating a piezoelectric material such as PZT or PVDF. The first adsorbing member 35 and the second adsorbing member 36 that adsorb volatile organic compounds are formed by depositing a material that adsorbs volatile organic compounds such as polybutadiene (PBD) on the upper surface of the beam member 31. Is provided.

  The first suction member 35, the second suction member 36, and the beam member 31 are formed of different materials. One end of the beam member 31 made of a polymer material that adsorbs a volatile organic compound is fixed to the support portion 33. The support part 33 is connected to the drive part 34. Thereby, the gas sensor 300 is configured such that the beam member 31 on which the first adsorption member 35 and the second adsorption member 36 are formed resonates with the vibration applied by the drive unit 34 and vibrates. Yes.

  Further, in the gas sensor 300, the vibration detection element 32 is laminated on the beam member 31. Thereby, the vibration of the beam member 31 is detected by the vibration detection element 32. Although not shown, wiring for detecting an electrical signal from the vibration detection element 32 is electrically connected to the signal processing unit.

  Next, the driving principle of the gas sensor 300 will be described. As shown in FIG. 3, one end of the beam member 31 is fixed to the support portion 33. The support part 33 is connected to the drive part 34. When the drive unit 34 vibrates, the beam member 31 vibrates at the resonance frequency.

  When the beam member 31 is exposed to the volatile organic compound, the volatile organic compound is adsorbed to a part of the beam member 31. Thereby, the mass of the beam member 31 increases. Further, when the first adsorbing member 35 is exposed to the volatile organic compound, the volatile organic compound is adsorbed on a part of the first adsorbing member 35. Thereby, the mass of the beam member 31 increases.

  Further, when the second adsorbing member 36 is exposed to the volatile organic compound, the volatile organic compound is adsorbed on a part of the second adsorbing member 36. Thereby, the mass of the beam member 31 increases. As a result, the resonance frequency of the beam member 31 is reduced by the mass of the volatile organic compound adsorbed on at least one of the beam member 31, the first adsorption member 35, and the second adsorption member 36.

  As shown in FIG. 3, a vibration detection element 32 is formed on the upper surface of the beam member 31. When the beam member 31 vibrates, stress is transmitted to the vibration detecting element 32. The vibration detection element 32 is a piezoelectric material. For this reason, the vibration detection element 32 generates a voltage by the applied stress. As a result, the resonance frequency of the beam member 31 is detected by measuring the voltage of the vibration detection element 32.

  Next, the operation of this embodiment will be described. The beam member 31 of the gas sensor 300 vibrates in resonance with the vibration applied by the drive unit 34. The vibration detection element 32 detects the vibration of the beam member 31. When at least one of the beam member 31, the first adsorbing member 35, and the second adsorbing member 36 adsorbs the volatile organic compound when the drive unit 34 vibrates the beam member 31 at the resonance frequency, the beam member 31. The mass of increases. Thereby, the resonant frequency of the beam member 31 falls. A change in resonance frequency is detected by the vibration detection element 32. As a result, the concentration of the volatile organic compound can be measured.

  Further, the beam member 31 of the gas sensor 300 of the present embodiment is formed of a polymer material having a low Young's modulus. Generally, in a gas sensor that detects a volatile organic compound, as described above, the sensitivity and the resonance frequency are in a proportional relationship. The resonance frequency of the beam member 31 is proportional to the square root of the Young's modulus and inversely proportional to the square of the length of the beam member. The Young's modulus of the polymer material of the beam member 31 of this embodiment, for example, 1 GPa or more and 10 GPa or less is lower than the Young's modulus of silicon of the conventional example. Thereby, the beam member of the same resonance frequency can be reduced in size.

  As described above, the sensor of this embodiment uses a polymer material instead of silicon as the material of the beam member 31 in the vibrator. The beam member 31 of the polymer material adsorbs a volatile organic compound. The first adsorbing member 35 fixed to the beam member 31 adsorbs a volatile organic compound different from that of the beam member 31.

The second adsorbing member 36 adsorbs a volatile organic compound different from that of the beam member 31 and the first adsorbing member 35. Thereby, there exists an effect that three types of volatile organic compounds can be detected with one gas sensor.
Further, by making the material of the beam member 31 a material having a low Young's modulus (for example, 1 GPa or more and preferably 10 GPa or less), the gas sensor can be reduced in size.
As shown in FIG. 3, in the present embodiment, the support portion 33 is connected to the drive portion 34. However, as will be described later, the support portion 33 may be attached to a vibrating device such as a mechanical device. .

(Fourth embodiment)
Next, the gas sensor 400 of 4th Embodiment is demonstrated. FIG. 4 is a perspective view showing the gas sensor 400. As shown in FIG. 4, the gas sensor 400 includes a first sensor unit 410 having a first beam member 411 and a first vibration detection element 412, a second beam member 421, and a second vibration detection element 422. A second sensor unit 420 including: an output signal of the first vibration detection element 412 from the first sensor unit 410; and an output signal of the second vibration detection element 422 from the second sensor unit 420. The first resonance frequency of the first sensor unit 410 of the first beam member 411 and the second beam member 421 oscillating in resonance with the applied vibration and the second of the second sensor unit 420. The signal processing unit 47 extracts two resonance frequencies and calculates a difference between the first resonance frequency and the second resonance frequency.

  Furthermore, the explanation will be continued specifically. The gas sensor 400 includes a first sensor unit 410, a second sensor unit 420, and a signal processing unit 47. The first sensor unit 410 includes a first beam member 411, a first vibration detection element 412, a support unit 43, and an adsorption member 45. The first vibration detection element 412 is provided by laminating a piezoelectric material such as PZT or PVDF on the upper surface of the first beam member 411.

  The adsorbing member 45 that adsorbs a volatile organic compound is provided by forming a film that adsorbs a volatile organic compound such as polybutadiene (PBD) on the upper surface of the first beam member 411. The adsorption member 45 and the first beam member 411 are formed of different materials.

  One end of the first beam member 411 made of a polymer material that adsorbs a volatile organic compound is fixed to the support portion 43. The support part 43 is connected to the drive part 44. Thereby, the first sensor unit 410 of the present embodiment vibrates in resonance with the vibration applied by the driving unit 44 to the first beam member 411 on which the adsorption member 45 is formed.

  Further, in the first sensor unit 410 of the present embodiment, the first vibration detection element 412 is laminated on the first beam member 411. Thereby, the vibration of the first beam member 411 is detected by the first vibration detection element 412.

  On the other hand, the second sensor unit 420 includes a second beam member 421, a second vibration detection element 422, and a support unit 43. The second beam member 421 and the first beam member 411 are formed of the same material. The second vibration detecting element 422 is provided on the upper surface of the second beam member 421 by laminating a piezoelectric material such as PZT or PVDF.

  One end of the second beam member 421 made of a polymer material that adsorbs a volatile organic compound is fixed to the support portion 43. The support part 43 is connected to the drive part 44. Thus, the second sensor unit 420 of the present embodiment is configured to vibrate in resonance with the vibration applied by the drive unit 44 of the second beam member 421.

  Further, in the second sensor unit 420, the second vibration detection element 422 is laminated on the second beam member 421. Thereby, the vibration of the second beam member 421 is detected by the second vibration detection element 422. In the present embodiment, the distance between the first sensor unit 410 and the second sensor unit 420 is about 500 μm or more.

  The signal processing unit 47 is connected to the first vibration detection element 412 of the first sensor unit 410 and the second vibration detection element 422 of the second sensor unit 420. Thereby, the vibration of the first beam member 411 detected by the first vibration detection element 412 and the vibration of the second beam member 421 detected by the second vibration detection element 422 are transmitted to the signal processing unit 47. Entered.

  Next, the driving principle will be described. As shown in FIG. 4, one end of the first beam member 411 of the first sensor unit 410 is fixed to the support unit 43. The support part 43 is connected to the drive part 44. When the drive unit 44 vibrates, the first beam member 411 vibrates at the resonance frequency.

  When the first beam member 411 is exposed to the volatile organic compound, the volatile organic compound is adsorbed on a part of the first beam member 411. Thereby, the mass of the 1st beam member 411 increases. Further, when the adsorbing member 45 is exposed to the volatile organic compound, the volatile organic compound is adsorbed to a part of the adsorbing member 45. Thereby, the mass of the 1st beam member 411 increases.

  As a result, the first resonance frequency of the first beam member 411 decreases due to the mass of the volatile organic compound adsorbed on the first beam member 411 or the adsorption member 45. Further, as shown in FIG. 4, a first vibration detection element 412 is formed on the upper surface of the first beam member 411. When the first beam member 411 vibrates, stress is transmitted to the first vibration detection element 412. Since the first vibration detection element 412 is a material having piezoelectricity, a voltage is generated by an applied stress.

  On the other hand, one end of the second beam member 421 of the second sensor unit 420 is fixed to the support unit 43. The support part 43 is connected to the drive part 44. When the drive unit 44 vibrates, the second beam member 421 vibrates at the resonance frequency. When the second beam member 421 is exposed to the volatile organic compound, the volatile organic compound is adsorbed on a part of the second beam member 421.

  Accordingly, the mass of the second beam member 421 increases. As a result, the second resonance frequency of the second beam member 421 decreases due to the mass of the volatile organic compound adsorbed on the second beam member 421. Further, as shown in FIG. 4, a second vibration detection element 422 is formed on the upper surface of the second beam member 421. When the second beam member 421 vibrates, stress is transmitted to the second vibration detecting element 422. Since the second vibration detecting element 422 is a material having piezoelectricity, a voltage is generated by an applied stress.

  Further, the signal processing unit 47 detects the vibrations of the first beam member 411 and the second beam member 421 that resonate with the vibration applied by the driving unit 44, and the first vibration detection element 412 and the second beam member 421. Extracted as the output voltage of the vibration detection element 422. Further, the signal processing unit 47 outputs the output voltages of the first vibration detection element 412 and the second vibration detection element 422 to the first resonance frequency of the first beam member 411 and the second resonance of the second beam member 421. Convert to frequency. Further, the signal processing unit 47 calculates a difference between the first resonance frequency and the second resonance frequency.

  The gas sensor 400 calculates the difference by extracting the first resonance frequency of the first beam member 411 and the second resonance frequency of the second beam member 421. Thereby, the difference in the amount of change between the first resonance frequency of the first sensor unit 410 and the second resonance frequency of the second sensor unit 420 can be measured.

  Next, the operation of this embodiment will be described. The first beam member 411 of the first sensor unit 410 and the second beam member 421 of the second sensor unit 420 vibrate in resonance with the vibration applied by the drive unit 44. The first vibration detection element 412 detects the vibration of the first beam member 411. The second vibration detection element 422 detects the vibration of the second beam member 421. The first beam member 411 and the suction member 45 are formed of different materials.

  The first beam member 411 and the second beam member 421 are made of the same polymer material. Volatile organic compounds differ in adsorption species and adsorption amount depending on the material. For example, when the drive unit 44 vibrates the first beam member 411 and the second beam member 421 at the resonance frequency in an atmosphere of a volatile organic compound adsorbed only by the adsorption member 45, the first sensor Since the mass of the first beam member 411 of the first sensor unit 410 increases when the adsorption member 45 of the unit 410 adsorbs the volatile organic compound, the resonance frequency of the first beam member 411 of the first sensor unit 410 is increased. Decreases. On the other hand, since the second beam member 421 of the second sensor unit 420 does not adsorb a volatile organic compound, the resonance frequency of the second beam member 421 of the second sensor unit 420 does not change.

  Further, if the first beam member 411 and the second beam member 421 are formed of the same polymer material, it is possible to cancel the fluctuation of the resonance frequency due to the temperature change of the same member.

  In the gas sensor 400 of this embodiment, a beam member formed of a polymer material of the first sensor unit 410 and the second sensor unit 420 adsorbs a volatile organic compound. Further, the adsorbing member 45 fixed to the first beam member 411 of the first sensor unit 410 adsorbs a volatile organic compound different from the first beam member 411.

  The signal processing unit 47 calculates the difference by extracting the resonance frequencies of the first sensor unit 410 and the second sensor unit 420 that have different volatile organic compounds to be adsorbed. Thereby, there exists an effect that the kind of volatile organic compound can be specified by utilizing the 1st beam member 411 and the 2nd beam member 421 effectively.

  In addition, as shown in FIG. 4, the beam member of the 1st sensor part 410 and the 2nd sensor part 420 may be the same material. Alternatively, by using different materials for the beam members of the first sensor unit 410 and the second sensor unit 420, there is no need to separately form a suction member. Furthermore, a third sensor unit and a fourth sensor unit may be added. As shown in FIG. 4, in the present embodiment, the support unit is connected to the drive unit. However, as will be described later, the support unit may be attached to a vibrating device such as a mechanical device.

  The first to fourth embodiments described above have the drive units 14, 24, 34, 44. That is, a beam member having at least one end fixed thereto, a support unit that supports the beam member, a drive unit that applies vibration so that the beam member resonates, and a vibration of the beam member that is fixed to the beam member is detected. In the gas sensor including the vibration detection element, the beam member is formed of a polymer material, and at least a part of the surface thereof is an adsorption region that adsorbs a volatile organic compound.

(Fifth embodiment)
The structure of the gas sensor of 1st Embodiment-4th Embodiment is not restricted to this. As described above, a drive unit (vibration source) may exist outside.

  FIG. 5 is a diagram illustrating a perspective configuration of a gas sensor 500 according to the fifth embodiment. Since the beam member 511, the vibration detection element 512, and the support part 513 are the same structures as 1st Embodiment, the overlapping description is abbreviate | omitted, for example.

  The gas sensor 500 of this embodiment has a beam member 511 that is fixed at least at one end and resonates and vibrates with an external drive unit (vibration source) 514 (indicated by a dotted line in the figure), and a support that supports the beam member 511. A gas sensor including a portion 513 and a vibration detecting element 512 that is fixed to the beam member 511 and detects the vibration of the beam member 511, wherein the beam member 511 is formed of a polymer material, and at least one of the surfaces of the beam member 511 The gas sensor may be an adsorption region 510 that adsorbs a volatile organic compound. As the external drive unit (vibration source) 514, for example, a vibration source in a factory or a vibration source in an automobile can be used. It is desirable that the beam member 511 has a shape that resonates with its vibration source.

  As described above, the present embodiment can take various modifications without departing from the spirit of the present embodiment.

  As described above, the gas sensor according to the present invention is suitable for a small sensor.

DESCRIPTION OF SYMBOLS 100 Gas sensor 10 Adsorption area | region 11 Beam member 12 Vibration detection element 13 Support part 14 Drive part

Claims (6)

A beam member having at least one end fixed and resonating with a vibration source to vibrate;
A support portion for supporting the beam member;
A gas sensor comprising a vibration detecting element fixed to the beam member and detecting the vibration of the beam member;
The beam member is formed of a polymer material;
A gas sensor, wherein at least a part of a surface of the beam member is an adsorption region that adsorbs a volatile organic compound.   The gas sensor according to claim 1, further comprising an adsorbing member fixed to a part of the beam member and adsorbing a volatile organic compound.   The gas sensor according to claim 1, further comprising at least two adsorbing members that are fixed to a part of the beam member and adsorb a volatile organic compound. A first sensor unit having the first beam member and the first vibration detection element;
A second sensor unit having the second beam member and the second vibration detection element;
The output signal of the first vibration detection element from the first sensor unit and the output signal of the second vibration detection element from the second sensor unit are input and resonate with the applied vibration. Extracting the first resonance frequency of the first sensor portion and the second resonance frequency of the second sensor portion of the first beam member and the second beam member that vibrate in response to the second beam member; The gas sensor according to claim 1, further comprising a signal processing unit that calculates a difference between the resonance frequency of 1 and the second resonance frequency. A beam member having at least one end fixed thereto;
A support portion for supporting the beam member;
A drive unit that applies vibration so that the beam member resonates;
A gas sensor comprising a vibration detecting element fixed to the beam member and detecting the vibration of the beam member;
The beam member is formed of a polymer material;
A gas sensor, wherein at least a part of a surface of the beam member is an adsorption region that adsorbs a volatile organic compound. A beam member having at least one end fixed and resonating with an external vibration source;
A support portion for supporting the beam member;
A gas sensor comprising a vibration detecting element fixed to the beam member and detecting the vibration of the beam member;
The beam member is formed of a polymer material;
A gas sensor, wherein at least a part of a surface of the beam member is an adsorption region that adsorbs a volatile organic compound.

Images