JP7370915B2 - sensing sensor - Google Patents

Description

The present invention relates to a sensing sensor equipped with a piezoelectric vibrator.

QCM (Quartz crystal microbalance) is sometimes used to sense substances contained in gas. Sensing by this QCM is performed based on changes in vibration frequency due to substances contained in the gas adhering to the electrodes of a crystal oscillator.A sensing sensor using this QCM includes a quartz crystal oscillator and its frequency It is configured so that the signal can be extracted.

Patent Document 1 discloses a gas measuring device including the sensing sensor. In the gas measuring device of Patent Document 1, a thin film that adsorbs a specific gas is formed on a crystal piece (crystal resonator) sandwiched between two electrodes. The crystal resonator is installed in a closed space, and the output vibration frequency is stored in the storage means over time. This gas measuring device is provided with a temperature sensor and a humidity sensor that respectively measure the temperature and humidity in the closed space, and it is shown that temporal changes in temperature and humidity are also stored in the storage means.

Further, as one type of QCM, TQCM (Thermoelectric QCM), which controls the temperature of a crystal resonator, is known. A sensing sensor using this TQCM may be configured to incorporate a thermoelectric element such as a Peltier element, and the crystal resonator is cooled and/or heated by the thermoelectric element.

By the way, molecular-sized foreign substances contained in gases become chemical contaminants, which can cause malfunctions in equipment used in environments containing such gases or deteriorate the quality of products manufactured in such environments. There is a risk that such problems may occur. For example, such problems can occur in clean rooms for manufacturing semiconductors and liquid crystal panels.Specific examples include deterioration of the voltage resistance of gate oxide films and damage to resist films formed on substrates. Possible causes include unevenness, variations in water repellency within the plane of the substrate, and exposure abnormalities due to fogging of the lens and mirror of the exposure machine. Against this background, there is a demand for increasing the sensitivity in sensing the above-mentioned foreign matter. Note that the foreign matter is, for example, what is called a non-volatile residue (NVR) that does not volatilize even when gas is heated and remains as a residue.

The lower the temperature of the crystal resonator, the higher the adhesion of NVR to the surface of the crystal resonator. Therefore, in order to configure the sensor to perform the TQCM described above and increase the sensitivity to NVR, One idea is to lower the temperature of the vibrator as much as possible. However, the above gas may contain substances that are not to be detected. For example, suppose that the gas is air, and moisture in the air is not to be sensed. Additionally, the temperature and humidity of the environment in which the NVR senses may vary. For example, suppose that NVR sensing is performed in the above-mentioned clean room. Although the temperature and humidity of the air in a clean room are controlled, they may become locally and/or temporarily high. For example, it is conceivable that the temperature and humidity may become higher due to the influence of materials brought into the clean room. Furthermore, it is conceivable that the humidity of the air in the clean room increases as the humidity of the air outside the clean room increases and that outside air is taken into the room.

Therefore, even if the temperature of the crystal resonator is adjusted by TQCM to a certain set temperature that does not cause condensation on the surface, taking into consideration the set temperature and humidity of the clean room, the condensation may occur. There is a risk of it getting lost. As dew condensation occurs, the surface of the electrodes of the crystal resonator becomes contaminated, making it impossible to sense the NVR. The device of Patent Document 1 described above cannot solve such problems. Note that the case where the above-mentioned dew condensation occurs will be explained in detail using a specific example in the embodiment of the invention.

Japanese Patent Application Publication No. 2011-106894

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to prevent dew condensation on the electrodes of the piezoelectric vibrator and set the temperature of the piezoelectric vibrator to a low level so as to sense a substance to be sensed with high sensitivity. The object of the present invention is to provide a sensing sensor that can perform the following steps.

The sensing sensor of the present invention is a sensing sensor for sensing a substance to be sensed that is contained in a gas atmosphere around the piezoelectric vibrator and is attached to the piezoelectric vibrator, based on a change in the oscillation frequency of the piezoelectric vibrator.
an oscillation circuit that oscillates the piezoelectric vibrator;
a gas detection unit that detects the temperature and humidity of the gas atmosphere;
a memory that stores data on the correspondence between the temperature and humidity detected by the gas detection unit and the temperature corresponding to the temperature of the piezoelectric vibrator;
a temperature detection section for a vibrator provided in the piezoelectric vibrator separately from the detection section for gas in order to detect the temperature of the piezoelectric vibrator;
temperature change of changing the temperature of the piezoelectric vibrator based on the data of the correspondence relationship, the temperature and humidity detected by the gas detection section , and the temperature detected by the vibrator temperature detection section; Department and
a case surrounding the piezoelectric vibrator, the gas detection section, and the vibrator temperature detection section;
a first vibration area including a first excitation electrode and a second vibration area including a second excitation electrode, each provided on the piezoelectric vibrator;
a cover that covers the second excitation electrode to suppress adhesion of a substance to be sensed to the second excitation electrode and also covers the temperature detection section for the vibrator;
It is characterized by having the following.

According to the sensing sensor of the present invention, data on the correspondence between the temperature and humidity of the gas atmosphere around the piezoelectric vibrator detected by the gas detection unit and the temperature corresponding to the temperature of the piezoelectric vibrator is stored. A memory is provided, and the temperature of the piezoelectric vibrator is changed based on the data and the temperature and humidity of the gas atmosphere. Therefore, while preventing dew condensation on the electrodes of the piezoelectric vibrator, the temperature of the piezoelectric vibrator is set low to promote adhesion of the substance to be sensed to the electrodes, and the substance to be sensed can be sensed with high sensitivity. be able to.

FIG. 1 is a block diagram of a sensing sensor according to an embodiment of the present invention. FIG. 3 is a schematic diagram of a table included in a memory constituting the sensing sensor. It is a chart figure showing the flow of sensing by the above-mentioned sensing sensor.

A sensing sensor 1, which is an embodiment of the present invention, will be described with reference to the block diagram of FIG. The sensing sensor 1 is installed, for example, in a clean room 11A in which semiconductor products and liquid crystal panels are manufactured. The sensing sensor 1 is configured to sense the NVR in the air in the clean room 11A using TQCM. Therefore, the NVR is the substance to be sensed, and the NVR is an unspecified substance other than water (water vapor) contained in the air. Note that in FIG. 1, signals transmitted and received at each part of the sensing sensor 1 are indicated by dotted arrows.

The sensing sensor 1 includes a cell 2, a first oscillation circuit 25A, a second oscillation circuit 25B, a controller 4, an AC adapter 45, an antenna 46, and a housing 11. The cell 2 is a case, in which a crystal resonator 3 which is a piezoelectric resonator, a Peltier element 23, a platinum sensor 21, a temperature/humidity sensor 22, and a support 36 are provided. The temperature of the crystal resonator 3 is set to a relatively low temperature to promote the adhesion of NVR. As described in the background art section, the temperature and/or humidity of the air in the clean room 11A may increase. When the dew point temperature of the air approaches the temperature of the crystal resonator 3 due to this increase in temperature and/or humidity, the temperature of the crystal resonator 3 is changed to prevent dew condensation on the surface of the electrodes of the crystal resonator 3. , the sensing sensor 1 is configured.

The configuration of the sensing sensor 1 will be described in detail below. The housing 11 includes side walls facing each other. One of the opposing side walls is provided with an inlet 12 that forms an air inlet, and the other of the opposing side walls is provided with an outlet 13 that forms an outlet that discharges air from outside the casing 11. It is provided.

The cell 2 described above is provided within the casing 11. Further, a gas flow path 14 connecting the inlet of the cell 2 and the inlet 12, and a gas flow path 15 connecting the outlet of the cell 2 and the outlet 13 are provided. A flow rate sensor 16 and a pump 17 are sequentially provided in the gas flow path 15 toward the downstream side. As the pump 17 operates, air outside the housing 11 is drawn through the inlet 12, passes through the cell 2, and is discharged from the outlet 13. The flow rate sensor 16 transmits a detection signal corresponding to the flow rate of air flowing through the gas flow path 15 to the controller 4. Based on the detection signal, the above control signal is sent to the pump 17, and the operation of the pump 17 is controlled so that air is supplied into the cell 2 at a desired flow rate.

Next, the crystal resonator 3 will be explained. The crystal resonator 3 includes a crystal piece 30. Excitation electrodes 31 and 32 are provided spaced apart from each other on the upper surface side of the crystal piece 30, and excitation electrodes 33 and 34 are provided spaced apart from each other on the lower surface side of the crystal piece 30. Excitation electrodes (referred to as first excitation electrodes) 31 and 33 form a pair and overlap each other with the crystal piece 20 in between. The excitation electrodes 32 and 34 (referred to as a second excitation electrode) form a pair and overlap each other with the crystal piece 30 in between. In the crystal blank 30, the region where the first excitation electrodes 31 and 33 are formed is referred to as a first vibration region 30A. In the crystal blank 30, the region where the second excitation electrodes 32 and 34 are formed is defined as a second vibration region 30B.

The support body 36 has a thick plate shape, and the peripheral edge of the crystal resonator 3 is supported at the opening edge of the recess 35 formed on the upper surface of the support body 36 . Therefore, the crystal resonator 3 closes the recess 35, and the first excitation electrode 33 and the second excitation electrode 34 are provided within the recess 35. Further, a cover 37 that covers the surface of the crystal resonator 3 is provided on the upper surface side of the support body 36. An opening 38 facing the first excitation electrode 31 is formed in the cover 37 . Therefore, the first excitation electrode 31 comes into contact with the air that has flowed into the cell 2 through the opening 38, but the cover 37 suppresses contact between the second excitation electrode 32 and the air.

A platinum sensor 21 is provided at the edge of the upper surface of the crystal resonator 3, for example inside the cover 37. This platinum sensor 21 is a temperature sensor for detecting the temperature of the crystal resonator 3, and sends a detection signal regarding the temperature of the crystal resonator 3 to a conductive path (not shown) provided on the support 36 and a radiator 24 (described later). The data is sent to the controller 4 via the . The temperature of the crystal oscillator 3 is controlled based on a detection signal from a platinum sensor 21, which is a temperature detection section for this oscillator.

A temperature and humidity sensor 22 is provided outside the support 36 to detect the temperature and humidity of the air taken into the cell 2. The temperature and humidity sensor 22, which is a gas detection section, transmits detection signals regarding the temperature and humidity to the controller 4 via a conductive path (not shown) provided in the radiator 24.

A Peltier element 23 serving as a temperature changing section is provided on the lower surface of the support 36 , and the Peltier element 23 is provided on a heat radiator 24 forming the bottom of the cell 2 . The Peltier element 23 can adjust the temperature of the crystal resonator 3 to a temperature lower than the set temperature of the air supplied into the cell 2 via the support 36 described above. The heat generated in the Peltier element 23 by this temperature adjustment is conducted to the heat radiator 24 and radiated to the outside of the cell 2 from the heat radiator 24 . In other words, the inside of the cell 2 is configured so as not to be affected by the heat generated by the Peltier element 23. The heat radiator 24 is configured, for example, by a heat sink with relatively high thermal conductivity, but may have any configuration. For example, fins may be provided that protrude toward the outside of the cell 2 in order to improve heat dissipation efficiency.

To further explain the Peltier element 23, power is supplied to the Peltier element 23 from an unillustrated power supply section, and the temperature of the contact surface that contacts the support body 36 decreases in accordance with the supplied power. This power supply is controlled by a control signal output from the controller 4, and the controller 4 outputs the control signal based on the detection signal output from the platinum sensor 21 described above. By controlling the temperature of the Peltier element 23 in this way, the temperature of the crystal oscillator 3 can be adjusted to a set temperature of an arbitrary value, and as described later, the temperature can be adjusted according to the dew point temperature. The temperature of the crystal resonator 3 can be changed so that .

A first oscillation circuit 25A and a second oscillation circuit 25B are provided outside the cell 2. The first oscillation circuit 25A and the second oscillation circuit 25B are connected to the first excitation electrode 31, the first excitation electrode 33, and the second are connected to the excitation electrode 32 and the second excitation electrode 34, respectively. Therefore, the first oscillation circuit 25A causes the first vibration region 30A of the crystal resonator 3 to oscillate, and the second oscillation circuit 25B causes the second vibration region 30B of the crystal resonator 3 to oscillate. The first oscillation circuit 25A and the second oscillation circuit 25B are connected to the controller 4, and each outputs a frequency signal to the controller 4. The frequency output from the first oscillation circuit 25A is f1, and the frequency output from the second oscillation circuit 25B is f2.

Next, the controller 4 will be explained. The controller 4 includes a CPU 41, a power supply circuit 42, a communication interface 43, and a memory 44. The CPU 41 receives each of the detection signals described above, outputs a control signal based on each detection signal, and transmits data to be described later, and executes each step of the flow described below. The power supply circuit 42 is connected to an AC adapter 45 provided outside the housing 11. The AC adapter 45 is connected to a power supply (not shown), and power is supplied to each circuit of the sensing sensor 1 via the power supply circuit 42. The communication interface 43 is provided to transmit the acquired data to, for example, a measuring device 50 provided outside the clean room 11A. This transmission is performed, for example, wirelessly, and an antenna 46 for performing the wireless transmission is connected to the communication interface 43, and the communication interface 43 and the antenna 46 constitute a wireless transmitter. The data wirelessly transmitted from the antenna 46 is, for example, data regarding frequencies f1 and f2 and the temperature detected by the platinum sensor 21 (temperature of the crystal resonator 3).

Next, the memory 44 will be explained with reference to FIG. The memory 44 stores a table showing the relationship between air temperature, air humidity (relative humidity), and dew point temperature. In the example shown in FIG. 2, the temperature is stored as an integer value in 1°C increments, and the humidity is stored as an integer value that is a multiple of 5 and in 5% increments, and the dew point temperature corresponding to each temperature and humidity is stored. is memorized.

In order to explain the role of the memory 44, the relationship among the temperature of the crystal resonator 3, the temperature of the air, the humidity of the air, and the dew point temperature will be specifically explained. Assume that in the clean room 11A, the air temperature is set to 25±1° C., and the air humidity (relative humidity) is set to 50±5%. From FIG. 2, in this temperature and humidity range, the dew point temperature of the air is the highest at 16.3° C. when the temperature is 26° C. and the humidity is 55%. That is, when the temperature of the crystal resonator 3 becomes 16.3° C. or lower, dew condensation occurs. That is, when the temperature and humidity are within the set range, no condensation occurs if the temperature of the crystal resonator 3 exceeds 16.3°C.

Therefore, in order to promote the adhesion of the NVR to the first excitation electrode 31, it is assumed that the temperature of the crystal resonator 3 is set as low as possible, for example, 18°C. At this time, it is assumed that the humidity of the air is within the above setting range of 50±5%. Looking at the dew point temperature within this humidity setting range in Figure 2, if the humidity is 55% and the air temperature is 28°C, the dew point temperature is 18.1°C, that is, the temperature of the crystal resonator 3. The value exceeds this value. That is, if the temperature of the air deviates from the above-mentioned setting range and reaches 28° C. or higher, dew condensation will occur on the surface of the crystal resonator 3.

Similarly, it is assumed that the temperature of the crystal resonator 3 is set to 18°C and the temperature of the air is within the set range of 25±1°C. Looking at the dew point temperature within this temperature setting range in Figure 2, if the temperature is 25°C and the humidity is 65%, the dew point temperature will be 18.0°C, which is the same as the set temperature of the crystal oscillator 3. . That is, if the humidity of the air deviates from the set range and reaches 65% or more, dew condensation will occur on the surface of the crystal resonator 3. In addition, although we have illustrated the range in which condensation occurs when one of the air temperature and humidity is within the set range, the dew point temperature is affected by both temperature and humidity. Therefore, if both the temperature and humidity are out of the set range, condensation will occur in a temperature or humidity range different from the illustrated range.

In the sensing sensor 1, in order to prevent dew condensation on the crystal oscillator 3, the temperature of the crystal oscillator 3 is changed when at least one of the air temperature and humidity is out of the set range as described above. This temperature change is performed based on data in a table stored in memory 44. Specifically, the temperature and humidity detected by the temperature/humidity sensor 22 are taken as the temperature and humidity of the clean room 11A, and the dew point temperature corresponding to the temperature and humidity is read out from the memory 44. Then, the threshold value corresponding to the read dew point temperature is compared with the temperature detected by the platinum sensor 21 (the temperature of the crystal resonator 3), and if the detected temperature is smaller, the crystal resonator 3 is Regardless of the set temperature, the temperature of the crystal resonator 3 is adjusted to reach the threshold value. This threshold value is, for example, the dew point temperature + a preset tolerance range, and the tolerance range is, for example, 3°C. In other words, the temperature of the crystal resonator 3 is controlled so as to ensure a difference of at least 3° C. with respect to the dew point temperature.

Then, when the temperature and humidity of the air fall within the set range, the temperature of the crystal resonator 3 is controlled to reach the set temperature. Therefore, the temperature of the crystal resonator 3 that deviates from the set temperature is temporary. Note that since the temperature of the crystal resonator 3 is determined according to the dew point temperature as described above,
The dew point temperature is a temperature corresponding to the temperature of the crystal resonator 3, and the table in the memory 44 corresponds to the correspondence between the temperature and humidity of the air and the temperature corresponding to the temperature of the crystal resonator 3.

As mentioned above, the dew point temperature is read out from the memory 44 based on the detected temperature and the detected humidity, but as mentioned above, the table stored in the memory 44 is divided into 1°C increments for temperature and 5% increments for humidity. It is data. Therefore, when the detected temperature does not match the temperature in the memory 44, for example, a dew point temperature corresponding to a temperature higher than the detected temperature and closest to the detected temperature is read out. Therefore, when the detected temperature is, for example, 26.5°C, the dew point temperature corresponding to 27°C is read. If the detected humidity does not match the humidity in the memory 44, for example, a dew point temperature corresponding to a humidity higher than the detected humidity and closest to the detected humidity is read out. Therefore, when the detected humidity is, for example, 56%, the dew point temperature corresponding to 60% is read out. Note that a table with finer increments regarding temperature and/or humidity may be stored in the memory 44. Note that the temperature of the crystal resonator 3 may be stored in the table instead of the dew point temperature. Further, instead of storing a table regarding temperature and humidity, a function using temperature and humidity as parameters is stored in the memory 44, and the temperature of the crystal resonator 3 is calculated from the detected temperature, the detected humidity, and the function. You can do it like this.

Next, the operation of the sensing sensor 1 will be explained with reference to the flowchart of FIG. First, temperature setting of the crystal resonator 3 (=temperature setting of the platinum sensor 21) for sensing is performed (step S1). This set temperature is a temperature at which dew condensation does not occur when the temperature and humidity of the air are each within the above set ranges.

After setting the temperature, the sensor 1 is operated, and the pump 17 supplies air from the clean room 11A into the cell 2 and discharges air from the cell 2. On the other hand, the temperature of the crystal resonator 3 is adjusted by the Peltier element 23 so that the temperature reaches the set temperature. A temperature detection signal is output from the platinum sensor 21 to the controller 4 and monitored (step S2). Furthermore, temperature and humidity detection signals are output from the temperature and humidity sensor 22 to the controller 4 and monitored (step S3).

The controller 4 determines from time to time whether the air temperature and humidity are within the set range based on the detection signal output from the temperature/humidity sensor 22, and if it is determined that the air temperature and humidity are within the set range, the controller 4 sets the temperature and humidity in step S1. The temperature of the crystal resonator 3 is controlled so as to reach the set temperature. If at least one of the temperature and humidity falls outside the set range, the controller 4 reads out the dew point temperature corresponding to the temperature and humidity detected by the temperature and humidity sensor 22 from the memory 44. Then, the controller 4 determines whether the temperature detected by the platinum sensor 21 acquired in step S2 (temperature of the crystal resonator 3)>threshold value (dew point temperature+permissible width) (step S4).

If it is determined in step S4 that the detected temperature does not exceed the threshold, the temperature of the Peltier element 23 is increased so that the detected temperature (that is, the temperature of the crystal resonator 3) becomes the threshold (step S5 ). That is, as described above, the temperature of the crystal resonator 3 is increased so that a 3° C. difference with respect to the dew point temperature is ensured. After that, each step S after step S2 is executed.

If it is determined in step S4 that the detected temperature is greater than the threshold, it is determined whether the detected temperature by the platinum sensor 21 acquired in step S2 is equal to or lower than the set temperature set in step S1. (Step S6). If it is determined in step S6 that the detected temperature is not lower than the set temperature, the temperature of the crystal resonator 3 is lowered by the Peltier element 23 (step S7). That is, since the temperature of the crystal oscillator 3 is higher than the set temperature, the temperature of the Peltier element 23 is lowered to adjust the temperature of the crystal oscillator 3 to the set temperature, and the crystal oscillator 3 is cooled.

If it is determined in step S6 that the detected temperature is below the set temperature, the temperature of the crystal resonator 3 is raised by the Peltier element 23, or the temperature is maintained as it is (step S8). In other words, since the temperature of the crystal resonator 3 is the same as the set temperature or lower than the set temperature, if it is lower than the set temperature, the temperature of the Peltier element 23 increases to match the set temperature, and the crystal resonator 3 is heated. When the detected temperature and the set temperature are equal, the temperature of the Peltier element 23 is maintained as it is. In this way, even if the temperature and/or humidity of the air deviates from the set range, as long as the temperature of the crystal resonator 3 does not approach the dew point, the temperature of the crystal resonator 3 is controlled to reach the set temperature. After performing steps S7 and S8, steps after step S2 are performed.

While the temperature of the crystal resonator 3 is controlled as described above, the frequencies f1 and f2 and the temperature detected by the platinum sensor 21 (the temperature of the crystal resonator 3) continue to be wirelessly transmitted from the antenna 46 to the measuring device 50. . NVR in the air passing through the cell 2 adheres to the surface of the first excitation electrode 31 of the crystal resonator 3, and the frequency f1 decreases according to the total mass of the attached NVR. On the other hand, since the cover 37 prevents NVR from adhering to the second excitation electrode 32, the decrease in frequency f2 is suppressed.

The user of the sensing sensor 1 can acquire NVR information from the difference value between the frequency f1 and the frequency f2 that are wirelessly transmitted as described above. Specifically, for example, the amount of NVR present in the clean room 11A, that is, the state of contamination can be estimated. Furthermore, it can be confirmed from the temperature of the crystal resonator 3 that is wirelessly transmitted that no dew condensation has occurred on the crystal resonator 3.

According to such a sensing sensor 1, the set temperature of the crystal oscillator 3 is made relatively low to promote adhesion of the NVR to the first excitation electrode 31, and the NVR can be sensed with high sensitivity. Therefore, dew condensation on the first excitation electrode 31 and the second excitation electrode 32 of the crystal resonator 3 can be prevented. Further, since the sensing sensor 1 acquires the changes in the frequencies f1 and f2 over time as described above, it is possible to grasp the change in the contamination status of the clean room 11A. In addition to the data on the frequencies f1 and f2, other information such as what was brought into the room and the time it took to bring it in can be used to identify the source of the contaminant.

By the way, in order to understand the state of contamination caused by NVR, a sample to which NVR is attached is placed in clean room 11A, exposed to indoor air, and then transported outside to undergo infrared spectroscopy and gas chromatography mass spectrometry. It is conceivable to perform various analyzes such as: However, transporting the sample is time-consuming, and depending on the type of analysis, it is necessary to perform pretreatment such as washing and heating the sample before using an analytical instrument. In other words, according to the sensing sensor 1, there is no need to carry such a sample outside the room or perform pretreatment, so there is an advantage that information about the NVR can be easily acquired.

Although the sensing sensor 1 has been described using as an example the case where it is used for sensing an NVR in the clean room 11A, it is not limited to being used for sensing foreign objects in such a place. For example, the sensing sensor 1 may be installed in a house whose room temperature is controlled by an air conditioner and used to sense house dust as the sensing substance. Furthermore, the sensing sensor 1 is not limited to being used in an environment containing air. The sensing sensor 1 may be used in an environment where nitrogen gas containing water vapor or the like is supplied instead of air to perform sensing so that the water vapor does not liquefy.

By the way, although the sensing sensor 1 has a configuration in which the frequencies f1 and f2 are transmitted wirelessly to the outside of the sensing sensor 1, a configuration in which the frequencies f1 and f2 are transmitted by wire may also be used. Further, the frequencies f1 and f2 are measured in advance at a place away from the environment where sensing is performed, and then the sensing sensor 1 is installed in the environment where sensing is performed. Then, after some time has elapsed, the sensing sensor 1 may be collected from the environment, and the frequencies f1 and f2 may be measured again to see the changes in the frequencies f1 and f2 during the previous measurement. In other words, it is not necessary to configure the frequency f1 and f2 to be transmitted to the outside of the sensing sensor 1. However, as described above, it is advantageous to be able to grasp changes in the frequencies f1 and f2 over time, so it is preferable to have a configuration in which the frequencies f1 and f2 can be transmitted to the outside. Moreover, although the configuration is such that the frequencies f1 and f2 can be acquired in order to further increase the sensing accuracy, the configuration may be such that the second vibration region 30B is not provided and only the frequency f1 is acquired.

Alternatively, the correspondence between the power supplied to the Peltier element 23 and the crystal resonator 3 may be obtained in advance, and the temperature of the crystal resonator 3 may be adjusted to a desired temperature according to the correspondence. In other words, the temperature of the crystal resonator 3 is controlled to a desired temperature by acquiring the temperature of the crystal resonator 3 with the platinum sensor 21, but the temperature of the crystal resonator 3 is not acquired and the temperature of the crystal resonator 3 is not acquired. A configuration may be adopted in which the temperature of the vibrator 3 is controlled. However, in order to more reliably prevent condensation on the crystal oscillator 3, the temperature of the crystal oscillator 3 is acquired using the platinum sensor 21, and the temperature of the crystal oscillator 3 is controlled based on the acquired temperature. It is preferable to use the configuration described above.

Furthermore, the temperature of the surface of the crystal resonator 3 is adjusted to be lower than the temperature of the air surrounding the crystal resonator 3, and the device is capable of promoting adhesion of the NVR to the first excitation electrode 31. The temperature adjustment may be performed, for example, the temperature of the crystal resonator 3 may be adjusted using a chiller. In other words, the temperature adjustment is not limited to using the Peltier element 23. However, in order to perform temperature adjustment with a simple configuration of the sensing sensor, it is preferable to use the Peltier element 23.

Note that the embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The embodiments described above may be omitted, replaced, modified, and combined in various forms without departing from the scope and spirit of the appended claims.

1 Sensing sensor 21 Platinum sensor 22 Temperature/humidity sensor 23 Peltier element 25A First oscillation circuit 3 Crystal resonator 44 Memory

Claims (7)

A sensing sensor for sensing a substance to be sensed contained in a gas atmosphere around the piezoelectric vibrator and attached to the piezoelectric vibrator based on a change in the oscillation frequency of the piezoelectric vibrator,
an oscillation circuit that oscillates the piezoelectric vibrator;
a gas detection unit that detects the temperature and humidity of the gas atmosphere;
a memory that stores data on the correspondence between the temperature and humidity detected by the gas detection unit and the temperature corresponding to the temperature of the piezoelectric vibrator;
a temperature detection section for a vibrator provided in the piezoelectric vibrator separately from the detection section for gas in order to detect the temperature of the piezoelectric vibrator;
temperature change of changing the temperature of the piezoelectric vibrator based on the data of the correspondence relationship, the temperature and humidity detected by the gas detection section , and the temperature detected by the vibrator temperature detection section; Department and
a case surrounding the piezoelectric vibrator, the gas detection section, and the vibrator temperature detection section;
a first vibration area including a first excitation electrode and a second vibration area including a second excitation electrode, each provided on the piezoelectric vibrator;
a cover that covers the second excitation electrode to suppress adhesion of a substance to be sensed to the second excitation electrode and also covers the temperature detection section for the vibrator;
A sensing sensor comprising: 2. The sensing sensor according to claim 1 , wherein the temperature changing section is configured to be able to cool the piezoelectric vibrator to a temperature lower than the temperature of the gas atmosphere. The sensing sensor according to claim 2 , wherein the temperature changing section includes a Peltier element provided within the case . The sensing sensor according to any one of claims 1 to 3 , further comprising a wireless transmitter that wirelessly transmits data regarding the output frequency of the oscillation circuit. the gas atmosphere is an air atmosphere;
5. The sensing sensor according to claim 1, wherein the temperature corresponding to the temperature of the piezoelectric vibrator in the memory is the dew point temperature of air. The sensing sensor according to any one of claims 1 to 5 , further comprising a pump for introducing the gas atmosphere outside the case into the case. 7. The oscillation circuit according to claim 1, wherein the oscillation circuit includes a first oscillation circuit that vibrates the first vibration region and the second vibration region, respectively, and a second oscillation circuit. Sensing sensor described.

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