JP7545904B2

JP7545904B2 - Detection sensor and detection device

Info

Publication number: JP7545904B2
Application number: JP2021011072A
Authority: JP
Inventors: 啓行茎田
Original assignee: Nihon Dempa Kogyo Co Ltd
Current assignee: Nihon Dempa Kogyo Co Ltd
Priority date: 2021-01-27
Filing date: 2021-01-27
Publication date: 2024-09-05
Anticipated expiration: 2041-01-27
Also published as: JP2022114684A

Description

本発明は、圧電振動子の周波数変化により被感知物質を感知する感知センサ、及び感知装置に関する。 The present invention relates to a sensor and a sensing device that detects a substance to be sensed by changes in the frequency of a piezoelectric vibrator.

ガス中に含まれる物質を感知する感知センサとして、水晶振動子を用いたＱＣＭ（Quartz crystal microbalance）が知られている。このようなＱＣＭを利用した感知手法の一つとして、水晶振動子に被感知物質の検出が行われるガスを吸着させた後、当該水晶振動子の温度を低温の状態から徐々に上げて、当該水晶振動子に吸着したガスを脱離させる手法が知られている。 Quartz crystal microbalance (QCM) using a quartz oscillator is known as a sensor for detecting substances contained in gas. One sensing method using such a QCM is to adsorb the gas for which the substance to be detected is to be detected onto the quartz oscillator, and then gradually increase the temperature of the quartz oscillator from a low temperature state to desorb the gas adsorbed onto the quartz oscillator.

当該手法においては、このガス脱離前後の周波数変化量を測定することでガスの吸着量が測定され、ガスが脱離する際の温度を検出することでガスの成分が特定される。上記の水晶振動子の温度変更を能動的に行うために熱電素子であるペルチェ素子を内蔵したものが知られている。ＱＣＭからガスを離脱させるための温度調節手段として、熱電素子を採用した感知装置は、ＴＱＣＭ（Thermoelectric QCM）とも呼ばれる。 In this method, the amount of gas adsorbed is measured by measuring the change in frequency before and after gas desorption, and the gas components are identified by detecting the temperature at the time of gas desorption. A device that incorporates a Peltier element, which is a thermoelectric element, to actively change the temperature of the above-mentioned quartz crystal oscillator is known. A sensing device that uses a thermoelectric element as a temperature adjustment means for desorbing gas from the QCM is also called a TQCM (Thermoelectric QCM).

このようなＴＱＣＭにおいて、近年では、測定感度の向上のため水晶振動子にガスを吸着させる励振電極である検出電極と、参照となる周波数を取得する励振電極である参照電極と、を設けた構成が知られている（例えば特許文献１）。このＴＱＣＭにおいては、被感知物質を吸着させた検出電極の発振周波数と、参照電極の発振周波数と、の周波数差分値を取得することで、被感知物質の吸着による質量変化以外の外来ノイズをキャンセルした周波数変化量を取得することができる。このようなＴＱＣＭにおいては、外来ノイズを確実にキャンセルし被感知物質の吸着による質量変化に基づく周波数変化量を、より正確に取得する要請がある。 In recent years, in order to improve measurement sensitivity, a configuration has been developed in which a detection electrode, which is an excitation electrode that adsorbs gas to a quartz crystal oscillator, and a reference electrode, which is an excitation electrode that acquires a reference frequency, are provided (see, for example, Patent Document 1). In this TQCM, by acquiring the frequency difference value between the oscillation frequency of the detection electrode that has adsorbed the substance to be sensed and the oscillation frequency of the reference electrode, it is possible to acquire a frequency change amount that cancels out external noise other than the mass change due to the adsorption of the substance to be sensed. In such TQCMs, there is a demand to reliably cancel external noise and more accurately acquire the frequency change amount based on the mass change due to the adsorption of the substance to be sensed.

なお特許文献２には、水中の油、ガス漏洩検知装置において、検知すべき物質をプリズムの検知面に収集するにあたって、検知孔を装置本体の外部から内部に向かってテーパー状に形成した構成が記載されている。しかしながら特許文献１は検出電極と参照電極とを備えた圧電振動子を用いて被感知物質を感知する技術の記載はなく、本発明の課題を解決する構成は開示されていない。 Patent document 2 describes a configuration for an underwater oil and gas leak detection device in which the detection hole is tapered from the outside to the inside of the device body in order to collect the substance to be detected on the detection surface of a prism. However, patent document 1 does not describe technology for detecting the substance to be detected using a piezoelectric vibrator equipped with a detection electrode and a reference electrode, and does not disclose a configuration that solves the problems of the present invention.

特開２０１９－１７４２６９号公報JP 2019-174269 A 特開平２－４９８８９号公報Japanese Patent Application Publication No. 2-49889

本発明は、このような事情に基づいてなされたものであり、被感知物質を検出用の励振電極に確実に吸着させると共に、圧電振動子を加熱したとき参照用の励振電極に加わる誤差の要因を抑制した感知センサを提供することにある。 The present invention was made based on these circumstances, and aims to provide a sensing sensor that reliably adsorbs the substance to be sensed to the detection excitation electrode and suppresses the cause of errors that occur in the reference excitation electrode when the piezoelectric vibrator is heated.

第一の発明の感知センサは、気体である被感知物質を圧電振動子に吸着させ、当該圧電振動子の温度を変化させて被感知物質を脱離させ、圧電振動子の発振周波数の変化と前記温度との関係に基づいて、被感知物質を感知するための感知センサにおいて、
共通の圧電片を挟んで、その一面側及び他面側に対向するように形成された２組の励振電極を互いに離間して設けてなる第１の振動領域及び第２の振動領域を備えると共にセンサ基板に保持された前記圧電振動子と、
前記センサ基板側からの伝熱により前記圧電振動子の温度を調節する温調機構と、
前記圧電振動子を前記一面側から覆うカバー部材と、を備え、
前記カバー部材は、前記圧電振動子の一面から離間して対向するように配置された対向面と、前記第１の振動領域を構成する前記一面側の励振電極が外部に向けて露出するように前記対向面に開口すると共に、前記一面から遠ざかるに従い開口径が次第に拡大する環状のテーパー面が形成されたガイドを有する開口部と、を備えることと、
前記カバー部材の前記対向面には、前記第２の振動領域を構成する前記一面側の励振電極と対向する領域に、黒色加工された黒体面が形成されていることと、
前記ガイドのテーパー面の上端と下端とを結んだ直線と、前記圧電振動子の一面と直交する軸線とのなす角度が４０°以上であることと、を特徴とする。
第二の発明の感知センサは、気体である被感知物質を圧電振動子に吸着させ、当該圧電振動子の温度を変化させて被感知物質を脱離させ、圧電振動子の発振周波数の変化と前記温度との関係に基づいて、被感知物質を感知するための感知センサにおいて、
共通の圧電片を挟んで、その一面側及び他面側に対向するように形成された２組の励振電極を互いに離間して設けてなる第１の振動領域及び第２の振動領域を備える前記圧電振動子と、
前記圧電振動子の温度を調節する温調機構と、
前記圧電振動子を前記一面側から覆うカバー部材と、を備え、
前記カバー部材は、前記圧電振動子の一面から離間して対向するように配置された対向面と、前記第１の振動領域を構成する前記一面側の励振電極が外部に向けて露出するように前記対向面に開口すると共に、前記一面から遠ざかるに従い開口径が次第に拡大する環状のテーパー面が形成されたガイドを有する開口部と、を備えることと、
前記カバー部材の前記対向面には、前記第２の振動領域を構成する前記一面側の励振電極と対向する領域に、黒色加工された黒体面が形成されていることと、
前記ガイドのテーパー面の上端と下端とを結んだ直線と、前記圧電振動子の一面と直交する軸線とのなす角度が４０°以上であることと、
前記黒体面が形成されている領域の周縁部から、前記第２の振動領域を構成する励振電極を囲み、前記圧電振動子の一面に近接する高さ位置へ向けて下方側に突出して形成された筒状の壁部が設けられていることと、を特徴とする。
第三の発明の感知センサは、気体である被感知物質を圧電振動子に吸着させ、当該圧電振動子の温度を変化させて被感知物質を脱離させ、圧電振動子の発振周波数の変化と前記温度との関係に基づいて、被感知物質を感知するための感知センサにおいて、
共通の圧電片を挟んで、その一面側及び他面側に対向するように形成された２組の励振電極を互いに離間して設けてなる第１の振動領域及び第２の振動領域を備える前記圧電振動子と、
前記圧電振動子の温度を調節する温調機構と、
前記圧電振動子を前記一面側から覆うカバー部材と、を備え、
前記カバー部材は、前記圧電振動子の一面から離間して対向するように配置された対向面と、前記第１の振動領域を構成する前記一面側の励振電極が外部に向けて露出するように前記対向面に開口すると共に、前記一面から遠ざかるに従い開口径が次第に拡大する環状のテーパー面が形成されたガイドを有する開口部と、を備えることと、
前記カバー部材の前記対向面には、前記第２の振動領域を構成する前記一面側の励振電極と対向する領域に、黒色加工された黒体面が形成されていることと、
前記ガイドのテーパー面の上端と下端とを結んだ直線と、前記圧電振動子の一面と直交する軸線とのなす角度が４０°以上であることと、
前記黒体面が形成された領域の前記対向面は、前記黒体面が形成されていない領域の前記対向面よりも前記圧電振動子の一面からの離間距離が大きいことと、を特徴とする。
A first aspect of the present invention is a sensing sensor for detecting a substance to be sensed, which is a gas, by adsorbing a substance to be sensed onto a piezoelectric vibrator, changing the temperature of the piezoelectric vibrator to cause the substance to be sensed to be desorbed, and detecting the substance to be sensed based on a relationship between a change in an oscillation frequency of the piezoelectric vibrator and the temperature, comprising:
a piezoelectric vibrator including a first vibration region and a second vibration region, the first vibration region and the second vibration region being spaced apart from each other and formed so as to face each other on one side and the other side of a common piezoelectric piece, the piezoelectric vibrator being supported by a sensor substrate ;
a temperature control mechanism for controlling the temperature of the piezoelectric vibrator by heat transfer from the sensor substrate ;
a cover member that covers the piezoelectric vibrator from the one surface side,
the cover member has an opposing surface disposed so as to face the one surface of the piezoelectric vibrator at a distance from the one surface, and an opening that opens on the opposing surface so that the excitation electrodes on the one surface side constituting the first vibration region are exposed to the outside, and has a guide formed with an annular tapered surface whose opening diameter gradually increases with increasing distance from the one surface;
A black body surface that is blackened is formed on the facing surface of the cover member in an area facing the excitation electrode on the one surface side that constitutes the second vibration area;
The angle between a straight line connecting the upper and lower ends of the tapered surface of the guide and an axis perpendicular to one surface of the piezoelectric vibrator is 40° or more.
A second aspect of the present invention is a sensing sensor for detecting a substance to be sensed, which is a gas, by adsorbing the substance to be sensed onto a piezoelectric vibrator, changing the temperature of the piezoelectric vibrator to cause the substance to be sensed to be desorbed, and detecting the substance to be sensed based on a relationship between a change in the oscillation frequency of the piezoelectric vibrator and the temperature, comprising:
The piezoelectric vibrator includes a first vibration region and a second vibration region, each of which is formed by sandwiching a common piezoelectric piece and providing two sets of excitation electrodes on one surface side and the other surface side of the common piezoelectric piece so as to face each other, the first vibration region and the second vibration region being spaced apart from each other;
A temperature control mechanism for controlling the temperature of the piezoelectric vibrator;
a cover member that covers the piezoelectric vibrator from the one surface side,
the cover member has an opposing surface disposed so as to face the one surface of the piezoelectric vibrator at a distance from the one surface, and an opening that opens on the opposing surface so that the excitation electrodes on the one surface side constituting the first vibration region are exposed to the outside, and has a guide formed with an annular tapered surface whose opening diameter gradually increases with increasing distance from the one surface;
A black body surface that is blackened is formed on the facing surface of the cover member in an area facing the excitation electrode on the one surface side that constitutes the second vibration area;
the angle between a straight line connecting the upper end and the lower end of the tapered surface of the guide and an axis perpendicular to one surface of the piezoelectric vibrator is 40° or more;
The piezoelectric vibrator is characterized in that a cylindrical wall portion is provided which surrounds the excitation electrode constituting the second vibration region from the peripheral portion of the region in which the blackbody surface is formed and protrudes downward toward a height position close to one surface of the piezoelectric vibrator.
A third aspect of the present invention is a sensing sensor for detecting a substance to be sensed, which is a gas, by adsorbing a substance to be sensed onto a piezoelectric vibrator, changing the temperature of the piezoelectric vibrator to cause the substance to be sensed to be desorbed, and detecting the substance to be sensed based on a relationship between a change in an oscillation frequency of the piezoelectric vibrator and the temperature, comprising:
The piezoelectric vibrator includes a first vibration region and a second vibration region, each of which is formed by sandwiching a common piezoelectric piece and providing two sets of excitation electrodes on one surface side and the other surface side of the common piezoelectric piece so as to face each other, the first vibration region and the second vibration region being spaced apart from each other;
A temperature control mechanism for controlling the temperature of the piezoelectric vibrator;
a cover member that covers the piezoelectric vibrator from the one surface side,
the cover member has an opposing surface disposed so as to face the one surface of the piezoelectric vibrator at a distance from the one surface, and an opening that opens on the opposing surface so that the excitation electrodes on the one surface side constituting the first vibration region are exposed to the outside, and has a guide formed with an annular tapered surface whose opening diameter gradually increases with increasing distance from the one surface;
A black body surface that is blackened is formed on the facing surface of the cover member in an area facing the excitation electrode on the one surface side that constitutes the second vibration area;
the angle between a straight line connecting the upper end and the lower end of the tapered surface of the guide and an axis perpendicular to one surface of the piezoelectric vibrator is 40° or more;
The opposing surface in the region where the blackbody surface is formed is spaced from one surface of the piezoelectric vibrator by a greater distance than the opposing surface in the region where the blackbody surface is not formed.

本感知センサは、被感知物質を吸着させる励振電極を有する第１の振動領域が外部に向けて露出するように開口する開口部を備えたカバー部材を用いて圧電振動子を覆う。この開口部は、電振動子の一面と直交する軸線とのなす角度が４０°以上のテーパー面が形成されたガイドを有しているので、外部環境の広い範囲からより確実に被感知物質を第１の振動領域に吸着させることができる。また参照用の励振電極を有する第２の振動領域と対向するカバー部材の対向面には、黒色加工された黒体面が形成されている。このように構成することで、カバー部材からの熱放射に伴う第２の振動領域の温度上昇を抑制し、安定した参照用の周波数信号を得ることができる。 This sensing sensor covers the piezoelectric vibrator with a cover member having an opening that exposes the first vibration region having an excitation electrode that adsorbs the substance to be sensed to the outside. This opening has a guide with a tapered surface that forms an angle of 40° or more with one surface of the piezoelectric vibrator and an axis perpendicular to the surface, so that the substance to be sensed can be more reliably adsorbed to the first vibration region from a wide range of external environments. In addition, a black body surface that has been blackened is formed on the opposing surface of the cover member that faces the second vibration region having the reference excitation electrode. This configuration makes it possible to suppress the temperature rise of the second vibration region due to heat radiation from the cover member, and to obtain a stable reference frequency signal.

本発明の実施形態に係る感知装置の縦断側面図である。1 is a longitudinal sectional side view of a sensing device according to an embodiment of the present invention. 前記感知装置の一部を拡大した縦断側面図である。FIG. 2 is an enlarged longitudinal sectional side view of a portion of the sensing device. 水晶振動子の平面図である。FIG. 感知センサを本体部に接続した感知装置を示すブロック図である。FIG. 2 is a block diagram showing a sensing device in which a sensing sensor is connected to a main body. 前記感知装置を用いてガス中の被感知物質を検出する実験装置の縦断側面図である。1 is a vertical cross-sectional side view of an experimental apparatus for detecting a substance to be sensed in a gas using the sensing device. 実施例及び比較例における昇温温度に対する周波数差分値の変化を示すグラフである。11 is a graph showing changes in frequency difference value with respect to heating temperature in an example and a comparative example.

本発明の一実施形態であるＴＱＣＭを利用した感知センサ１について、図１の縦断側面図を参照して説明する。感知センサ１は、ベース部２の上方に、回路収納部３、スペーサ６１、ペルチェ素子部６が積層され、ペルチェ素子部６の上方に水晶振動子４を支持するセンサ基板５が設けられている。以下明細書中では、ベース部２側を下方側、センサ基板５側を上方側として説明する。ただしこの方向については説明の便宜上設定したものであり、ここで示す方向となるように使用時の感知センサ１の配置方向が限定されるものでは無い。そしてこれら回路収納部３、スペーサ６１及びペルチェ素子部６、センサ基板５の上方を覆うようにカバー部材（以下、単に「カバー」という）１０が設けられている。 The detection sensor 1 using TQCM, which is one embodiment of the present invention, will be described with reference to the vertical cross-sectional side view of FIG. 1. The detection sensor 1 has a circuit storage section 3, a spacer 61, and a Peltier element section 6 stacked above a base section 2, and a sensor board 5 supporting a quartz crystal oscillator 4 is provided above the Peltier element section 6. In the following description, the base section 2 side will be described as the lower side, and the sensor board 5 side as the upper side. However, this direction is set for the convenience of explanation, and the arrangement direction of the detection sensor 1 during use is not limited to the direction shown here. A cover member (hereinafter simply referred to as "cover") 10 is provided to cover the circuit storage section 3, the spacer 61, the Peltier element section 6, and the upper part of the sensor board 5.

この感知センサ１は、ペルチェ素子部６によって、水晶振動子４の温度を例えば－８０℃～＋１２５℃の範囲内で変更できるように構成されている。ペルチェ素子部６は、温調機構に相当する。回路収納部３は水晶振動子４の発振周波数を感知センサ１の外部の装置へ取り出すための後述の発振回路９１、９２が収容される。またベース部２は、ペルチェ素子部６から放出される熱を外部へ排熱するための冷却部７１に接続できるように構成されている。 This detection sensor 1 is configured so that the temperature of the quartz oscillator 4 can be changed within a range of, for example, -80°C to +125°C by the Peltier element section 6. The Peltier element section 6 corresponds to a temperature adjustment mechanism. The circuit housing section 3 houses oscillation circuits 91, 92 (described below) for outputting the oscillation frequency of the quartz oscillator 4 to an external device of the detection sensor 1. The base section 2 is also configured so that it can be connected to a cooling section 71 for dissipating heat emitted from the Peltier element section 6 to the outside.

ベース部２は、例えばニッケル鍍金がされた銅により構成されている。ベース部２は平面視円形なブロックとして構成されており、高い伝熱性が得られるように成形されている。
回路収納部３は、ベース部２の上方にＦＰＧＡ（Field-Programmable Gate Array）などからなる集積回路３１を収納する密閉された収納空間３０形成する。集積回路３１はシリコン製の半導体素子によって構成されており、水晶振動子４に接続されて当該水晶振動子４を発振させる発振回路を含む。 The base portion 2 is made of, for example, nickel-plated copper, and is configured as a block having a circular shape in a plan view, and is shaped so as to obtain high thermal conductivity.
The circuit housing 3 forms a sealed housing space 30 above the base 2 for housing an integrated circuit 31 such as an FPGA (Field-Programmable Gate Array). The integrated circuit 31 is made of a silicon semiconductor element, and includes an oscillation circuit that is connected to the crystal unit 4 and causes the crystal unit 4 to oscillate.

ペルチェ素子部６は、その上面及び下面のうちの一方の面が放熱面（加熱面）、他方の面が冷却面となる。本例においては、ペルチェ素子部６へ供給される電流の方向が切り替えられることによって放熱面と冷却面とが互いに切り替えられて、水晶振動子４の冷却と加熱とを行うことができる。水晶振動子４を冷却する際にはペルチェ素子部６の上面が冷却面となり、その下面が放熱面となる。水晶振動子４を加熱する際にはペルチェ素子部６の上面が放熱面となり、その下面が冷却面となる。 One of the upper and lower surfaces of the Peltier element unit 6 serves as a heat dissipation surface (heating surface), and the other surface serves as a cooling surface. In this example, the direction of the current supplied to the Peltier element unit 6 is switched to switch between the heat dissipation surface and the cooling surface, thereby allowing the crystal oscillator 4 to be cooled and heated. When cooling the crystal oscillator 4, the upper surface of the Peltier element unit 6 serves as the cooling surface, and its lower surface serves as the heat dissipation surface. When heating the crystal oscillator 4, the upper surface of the Peltier element unit 6 serves as the heat dissipation surface, and its lower surface serves as the cooling surface.

図１に示すようにセンサ基板５は、凹部５１を備え、後述する水晶振動子４の第１及び第２の振動領域４５、４６の下面側が凹部５１に臨むように、水晶振動子４の周縁部を下面側から支え、且つ水平姿勢で保持できるように構成されている。またセンサ基板５は、その下面側中央がペルチェ素子部６の一面と接触した状態で保持されている。 As shown in FIG. 1, the sensor substrate 5 has a recess 51 and is configured to support the peripheral portion of the quartz oscillator 4 from below and hold it in a horizontal position so that the undersides of the first and second vibration regions 45, 46 of the quartz oscillator 4 (described later) face the recess 51. The sensor substrate 5 is held with the center of its underside in contact with one surface of the Peltier element portion 6.

図１に示すように、水晶振動子４は、例えばＡＴカットの圧電片である円形の水晶片４０を備えている。この水晶片４０の一面側（上面側）及び他面側（下面側）には、夫々例えば金（Ａｕ）などからなり、各々円形に形成された一対の第１の励振電極（検出電極）４１、４３と、一対の第２の励振電極（参照電極）４２、４４とが互いに離間して配置されている。水晶振動子４における第１の励振電極４１、４３に挟まれた領域は、第１の振動領域４５を構成し、第２の励振電極４２、４４に挟まれた領域は第２の振動領域４６を構成する。なお第１及び第２の励振電極４１～４４は、水晶片４０と比較して極めて薄い膜厚であるが、図１、図２では膜厚を誇張して記載している。従って水晶振動子４における水晶片４０の上面の高さ位置と、上面側の第１の励振電極４１、第２の励振電極４２の一面の高さ位置とは実際にはほぼ面一となっている。 As shown in FIG. 1, the quartz crystal unit 4 includes a circular quartz crystal piece 40, which is, for example, an AT-cut piezoelectric piece. On one side (top side) and the other side (bottom side) of the quartz crystal piece 40, a pair of first excitation electrodes (detection electrodes) 41, 43 and a pair of second excitation electrodes (reference electrodes) 42, 44, each of which is made of, for example, gold (Au) and formed into a circle, are arranged at a distance from each other. The area of the quartz crystal unit 4 sandwiched between the first excitation electrodes 41, 43 constitutes a first vibration area 45, and the area of the quartz crystal unit 4 sandwiched between the second excitation electrodes 42, 44 constitutes a second vibration area 46. The first and second excitation electrodes 41 to 44 are extremely thin compared to the quartz crystal piece 40, but the thicknesses are exaggerated in FIG. 1 and FIG. 2. Therefore, the height position of the top surface of the quartz crystal piece 40 in the quartz crystal resonator 4 and the height positions of one surface of the first excitation electrode 41 and the second excitation electrode 42 on the top side are actually almost flush with each other.

続いてカバー１０について、図２、図３も参照して説明する。カバー１０は例えば銅やアルミニウムで構成され、天板１０ａによって上面が覆われた円筒として構成されている。当該カバー１０の下面は開口しており、既述の回路収納部３からセンサ基板５に至る積層体を収容した状態で、ベース部２上に配置される。このときカバー１０の天板１０ａは水平に配置され、センサ基板５に支持された水晶振動子４の一面（上面）と、当該一面に対向する天板１０ａの下面（対向面）とが隙間を開けて離間して配置される。 Next, the cover 10 will be described with reference to Figs. 2 and 3. The cover 10 is made of, for example, copper or aluminum, and is configured as a cylinder whose upper surface is covered by a top plate 10a. The bottom surface of the cover 10 is open, and it is placed on the base portion 2 with the laminated body from the circuit storage portion 3 to the sensor board 5 housed therein. At this time, the top plate 10a of the cover 10 is placed horizontally, and one surface (top surface) of the quartz crystal oscillator 4 supported by the sensor board 5 and the bottom surface (opposing surface) of the top plate 10a that faces the one surface are placed apart with a gap between them.

そして、カバー１０の天板１０ａには、水晶振動子４の上面側に設けられた検出電極である第１の励振電極４１が外部へ向けて露出するように、円形の開口部１１開口している。さらに開口部１１には、上記の水晶振動子４の上面側の第１の振動領域４５を構成する第１の励振電極４１に被感知物質であるガスを第１の振動領域４５の一面に案内するための、ガイド１２が形成されている。ガイド１２の上面側には、カバー９の上面から下方へと延伸されると共に、水晶片４０の上面から遠ざかるに従い開口径が次第に拡大する環状のテーパー面１２ｂが形成されている。ガイド１２の下端は、水晶振動子４の上面からわずかに離間し（例えば離間間隔が０．５ｍｍ）、第１の振動領域４５の周縁を囲むように配置されている。 The top plate 10a of the cover 10 has a circular opening 11 so that the first excitation electrode 41, which is a detection electrode provided on the upper surface side of the quartz crystal oscillator 4, is exposed to the outside. Furthermore, a guide 12 is formed in the opening 11 to guide the gas, which is the substance to be sensed, to one side of the first vibration region 45 of the first excitation electrode 41 that constitutes the first vibration region 45 on the upper surface side of the quartz crystal oscillator 4. On the upper surface side of the guide 12, an annular tapered surface 12b is formed, which extends downward from the upper surface of the cover 9 and whose opening diameter gradually increases as it moves away from the upper surface of the quartz crystal piece 40. The lower end of the guide 12 is slightly spaced from the upper surface of the quartz crystal oscillator 4 (for example, the distance is 0.5 mm) and is arranged to surround the periphery of the first vibration region 45.

また水晶振動子４の上面に対して鉛直に伸びる軸線Ｌとの間に形成される角度に着目したとき、ガイド１２には、既述のテーパー面１２ｂの下端部に、当該テーパー面１２ｂよりも傾きが大きい急傾斜面１２ａが接続されている。
この例では軸線Ｌに対して急傾斜面１２ａのなす角度は、２０°、テーパー面１２ｂのなす角度が６０°に設定されている。 Furthermore, when attention is paid to the angle formed between the upper surface of the quartz crystal oscillator 4 and the axis L extending vertically, a steeply inclined surface 12a, which has a greater inclination than the tapered surface 12b, is connected to the lower end of the tapered surface 12b described above.
In this example, the angle of the steeply inclined surface 12a with respect to the axis L is set to 20°, and the angle of the tapered surface 12b is set to 60°.

また図２、図３に示すように、カバー１０の天板１０ａの下面には、筒状の壁部１３が設けられている。壁部１３は、天板１０ａの下面、即ち、水晶振動子４の上面と対向する対向面から、水晶振動子４の上面に近接する高さ位置へ向けて下方側に突出して形成されている。壁部１３の下端は、水晶振動子４の上面からわずかに離間し（例えば離間間隔が０．５ｍｍ）、参照電極側の第２の励振電極４２の周縁を囲むように配置されている。 As shown in Figs. 2 and 3, a cylindrical wall portion 13 is provided on the lower surface of the top plate 10a of the cover 10. The wall portion 13 is formed so as to protrude downward from the lower surface of the top plate 10a, i.e., the surface facing the upper surface of the quartz crystal oscillator 4, to a height position close to the upper surface of the quartz crystal oscillator 4. The lower end of the wall portion 13 is slightly spaced from the upper surface of the quartz crystal oscillator 4 (e.g., a spacing of 0.5 mm) and is disposed so as to surround the periphery of the second excitation electrode 42 on the reference electrode side.

また壁部１３で囲まれた領域は、壁部１３の外側の領域と比較して天板１０ａが薄くなっている。従って、図２に示すように、壁部１３の内側における天板１０ａの下面は、壁部１３の外側の領域における天板１０ａの下面と比較して、水晶振動子４の上面からの離間距離が大きくなっている。ここでは壁部１３の内側における離間距離ｈ１は、４ｍｍ、外側における離間距離ｈ２は２ｍｍとする場合を例示できる。
そしてカバー９の内面には、全面に亘って黒色メッキ１４の層を形成することにより黒色加工が成されている。 Furthermore, the top plate 10a is thinner in the region surrounded by the wall portion 13 than in the region outside the wall portion 13. Therefore, as shown in Fig. 2, the lower surface of the top plate 10a inside the wall portion 13 is spaced farther from the upper surface of the quartz crystal resonator 4 than the lower surface of the top plate 10a in the region outside the wall portion 13. Here, the case can be illustrated in which the distance h1 inside the wall portion 13 is 4 mm, and the distance h2 outside the wall portion 13 is 2 mm.
The inner surface of the cover 9 is blackened by forming a layer of black plating 14 over the entire surface.

図４は、感知センサ１を感知装置の本体部１００に接続したときに形成される電気的構成を示している。感知センサ１の第１及び第２の励振電極４１～４４は、集積回路３１に設けられた第１及び第２の発振回路９１、９２に接続されている。そして感知センサ１を感知装置の本体部１００に接続すると第１及び第２の発振回路９１、９２は、スイッチ９０を介して周波数取得部であるデータ処理部９３に接続される。データ処理部９３は、第１及び第２の発振回路９１、９２から入力された周波数信号の周波数データのディジタル値を取得する。この結果、経時的出力される周波数信号につき、第１の発振回路９１より出力される第１の発振周波数「Ｆ１」の時系列データと、第２の発振回路９２より出力される第２の発振周波数「Ｆ２」の時系列データとが得られる。 Figure 4 shows the electrical configuration formed when the sensing sensor 1 is connected to the main body 100 of the sensing device. The first and second excitation electrodes 41-44 of the sensing sensor 1 are connected to the first and second oscillation circuits 91, 92 provided in the integrated circuit 31. When the sensing sensor 1 is connected to the main body 100 of the sensing device, the first and second oscillation circuits 91, 92 are connected to the data processing unit 93, which is a frequency acquisition unit, via the switch 90. The data processing unit 93 acquires digital values of the frequency data of the frequency signals input from the first and second oscillation circuits 91, 92. As a result, for the frequency signals output over time, time series data of the first oscillation frequency "F1" output from the first oscillation circuit 91 and time series data of the second oscillation frequency "F2" output from the second oscillation circuit 92 are obtained.

本例の感知装置では、スイッチ９０により、第１の発振回路９１とデータ処理部９３とを接続するチャンネル１と、第２の発振回路９２とデータ処理部９３とを接続するチャンネル２とを交互に切り替えた間欠発振を行う。この手法により、感知センサ１の検出電極である第１の励振電極４１、４３と、参照電極である第２の励振電極４２、４４と、間の干渉を避け、安定した周波数信号を取得できるようにしている。そしてこれらの周波数信号は、例えば時分割されて、データ処理部９３に取り込まれる。データ処理部９３では、周ディジタル値の時分割データに基づいて、演算処理を行い、第１の発振回路９１の発振周波数と、第２の発振回路９２の発振周波数との周波数差分値を取得する。 In the sensing device of this example, intermittent oscillation is performed by alternately switching between channel 1, which connects the first oscillation circuit 91 and the data processing unit 93, and channel 2, which connects the second oscillation circuit 92 and the data processing unit 93, using a switch 90. This method avoids interference between the first excitation electrodes 41 and 43, which are the detection electrodes of the sensing sensor 1, and the second excitation electrodes 42 and 44, which are the reference electrodes, making it possible to obtain stable frequency signals. These frequency signals are then, for example, time-shared and input to the data processing unit 93. The data processing unit 93 performs arithmetic processing based on the time-shared data of the frequency digital value, and obtains the frequency difference value between the oscillation frequency of the first oscillation circuit 91 and the oscillation frequency of the second oscillation circuit 92.

図５は、上述の感知センサ１を備えた感知装置を用いて、ガス中の被感知物質を検出する実験装置の一例を示している。実験装置は、真空容器７０を備え、この真空容器７０の一面（図５に示す例では側面）は、感知センサ１を冷却するための冷却部７１として構成されている。そして図５に示す例において、感知センサ１は、冷却部７１にベース部２が固定され、開口部１１が側方を向くように取り付けられる。冷却部７１は例えば冷媒が流通する流路７１ａを備えたチラーにより構成され、ベース部２を冷却できるように構成されている。これにより感知センサ１は、ベース部２を介して、その全体が冷却される。これを言い替えると、感知センサ１内のペルチェ素子部６から放出された熱は、ベース部２に排出される。反対に、ペルチェ素子部６が、水晶振動子４を冷却部７１よりも低温に冷却している場合には、冷却部７１からペルチェ素子部６へ向けて給熱が行われる。 Figure 5 shows an example of an experimental apparatus for detecting a substance to be detected in a gas using a sensing device equipped with the above-mentioned sensing sensor 1. The experimental apparatus includes a vacuum container 70, and one surface of the vacuum container 70 (the side surface in the example shown in Figure 5) is configured as a cooling unit 71 for cooling the sensing sensor 1. In the example shown in Figure 5, the sensing sensor 1 is attached such that the base unit 2 is fixed to the cooling unit 71 and the opening 11 faces to the side. The cooling unit 71 is configured, for example, as a chiller equipped with a flow path 71a through which a refrigerant flows, and is configured to be able to cool the base unit 2. As a result, the sensing sensor 1 is cooled as a whole through the base unit 2. In other words, the heat released from the Peltier element unit 6 in the sensing sensor 1 is discharged to the base unit 2. Conversely, when the Peltier element unit 6 cools the quartz oscillator 4 to a temperature lower than that of the cooling unit 71, heat is supplied from the cooling unit 71 to the Peltier element unit 6.

真空容器７０の内部には、感知センサ１の開口部１１と対向する位置に試料７７を支持するための台部７３が設けられている。この台部７３は、加熱機構７４により試料７７を所定の温度に加熱できるようになっている。真空容器７０は、排気路７５を介して真空排気機構７６に接続され、所定の真空度に真空排気されるように構成されている。そしてまた感知センサ１を冷却部７１に取り付けたときに、集積回路３１と本体部１００とが互いに接続され、水晶振動子４の発振周波数を取得できるように構成されている。 Inside the vacuum vessel 70, a stand 73 for supporting a sample 77 is provided at a position facing the opening 11 of the detection sensor 1. This stand 73 is designed so that the sample 77 can be heated to a predetermined temperature by a heating mechanism 74. The vacuum vessel 70 is connected to a vacuum exhaust mechanism 76 via an exhaust path 75, and is configured so that it can be evacuated to a predetermined degree of vacuum. When the detection sensor 1 is attached to the cooling section 71, the integrated circuit 31 and the main body section 100 are connected to each other, and the oscillation frequency of the quartz crystal oscillator 4 can be obtained.

この実験装置においては、台部７３に試料７７を支持させた後、真空容器７０を閉じ、真空容器７０内を所定の真空度に真空排気すると共に、台部７３を加熱機構７４により例えば１２５℃に加熱する。これにより、試料７７に含まれる被感知物質であるガスが昇華し、真空容器７０内に放出される。一方、冷却部７１に冷却媒体を供給すると共に、ペルチェ素子部６により温度を調整し、水晶振動子４を、例えば－８０℃に冷却する。これにより、試料７７の加熱により発生したガスが開口部１１を介して感知センサ１内に進入し一面側の第１の励振電極４１に吸着する。これにより質量負荷効果により、第１の振動領域４５側の発振周波数が変化する。 In this experimental device, after the sample 77 is supported on the base 73, the vacuum container 70 is closed, the inside of the vacuum container 70 is evacuated to a predetermined vacuum level, and the base 73 is heated to, for example, 125°C by the heating mechanism 74. As a result, the gas to be sensed contained in the sample 77 sublimes and is released into the vacuum container 70. Meanwhile, a cooling medium is supplied to the cooling unit 71, and the temperature is adjusted by the Peltier element unit 6 to cool the quartz crystal oscillator 4 to, for example, -80°C. As a result, the gas generated by heating the sample 77 enters the sensing sensor 1 through the opening 11 and is adsorbed to the first excitation electrode 41 on one side. As a result, the oscillation frequency on the first vibration region 45 side changes due to the mass load effect.

このように、第１の振動領域４５においては、ガスが吸着して発振周波数が変化する一方で、第２の振動領域４６においては、ガスは吸着しない。このことから第１の振動領域４５と第２の振動領域４６との間で発振周波数の差が発生する。そこでこれらの発振周波数の差分値を得ることにより、温度変化などの外来ノイズをキャンセルし、ガスの吸着量の差に基づく発振周波数の変化量を取得することができる。 In this way, in the first vibration region 45, gas is adsorbed and the oscillation frequency changes, whereas in the second vibration region 46, gas is not adsorbed. This causes a difference in oscillation frequency between the first vibration region 45 and the second vibration region 46. Therefore, by obtaining the difference between these oscillation frequencies, it is possible to cancel external noise such as temperature changes and obtain the amount of change in oscillation frequency based on the difference in the amount of gas adsorbed.

次いで、周波数差分値の取得を行いながらペルチェ素子部６により温度を調節し、水晶振動子４を例えば１℃／分の速度で昇温させる。この昇温により、第１の振動領域４５に吸着した被感知物質が次第に昇華して脱離していく。この結果、第１、第２の振動領域４５、４６間の周波数差分値が小さくなる。圧力を一定にした条件下（本例では真空雰囲気）では、各物質の昇華温度が相違するので、水晶振動子４の温度と、周波数差分値の変化との対応関係から、被感知物質の特定し、各被感知物質の吸着量を求めることができる。 Next, while acquiring the frequency difference value, the temperature is adjusted by the Peltier element unit 6, and the crystal oscillator 4 is heated at a rate of, for example, 1°C/min. This temperature increase causes the sensed substance adsorbed to the first vibration region 45 to gradually sublime and desorb. As a result, the frequency difference value between the first and second vibration regions 45, 46 becomes smaller. Under conditions of constant pressure (vacuum atmosphere in this example), the sublimation temperatures of each substance differ, so the sensed substance can be identified and the adsorption amount of each sensed substance can be obtained from the correspondence between the temperature of the crystal oscillator 4 and the change in the frequency difference value.

図５に示す実験装置において、感知センサ１の開口部１１のガイド１２のテーパー面１２ｂの角度を大きくすると開口径が大きくなり被感知物質が開口部１１に進入しやすくなる。この結果、第１の振動領域４５に被感知物質を確実に吸着させることができる。 In the experimental device shown in FIG. 5, increasing the angle of the tapered surface 12b of the guide 12 of the opening 11 of the sensing sensor 1 increases the opening diameter, making it easier for the substance to be sensed to enter the opening 11. As a result, the substance to be sensed can be reliably adsorbed to the first vibration area 45.

しかしながら、テーパー面１２ｂの角度を大きくしていくと、水晶振動子４に対してカバー１０の天板１０ａが近づく。
このように天板１０ａと水晶振動子４との距離が近くなると、例えば加熱されている水晶振動子４から放射された熱が、天板１０ａの下面にて反射し、水晶振動子４に到達し、水晶振動子４の温度制御に影響を及ぼしやすくなるおそれが生じる。 However, when the angle of the tapered surface 12 b is increased, the top plate 10 a of the cover 10 approaches the crystal unit 4 .
When the distance between the top plate 10a and the quartz oscillator 4 becomes short in this manner, for example, heat radiated from the heated quartz oscillator 4 may be reflected on the underside of the top plate 10a, reach the quartz oscillator 4, and potentially affect the temperature control of the quartz oscillator 4.

一方、第１の振動領域４５は、開口部１１に臨むように配置され、天板１０ａとは対向していないため、既述の熱反射の影響を受けにくい。
そのため共通の水晶片４０に形成された第２の振動領域４６の温度が第１の振動領域４５の温度よりも高くなることがある。このように第１の振動領域４５と第２の振動領域４６との間で温度差が生じると、温度差の影響をキャンセルすることができず、被感知物質の吸着に基づく周波数差分値を正確に取得できなくなり、検出精度が低下してしまうおそれが生じる。 On the other hand, the first vibrating region 45 is disposed so as to face the opening 11 and does not face the top plate 10a, and is therefore less susceptible to the above-mentioned heat reflection.
Therefore, the temperature of the second vibration region 46 formed on the common quartz crystal piece 40 may become higher than the temperature of the first vibration region 45. When a temperature difference occurs between the first vibration region 45 and the second vibration region 46 in this way, the effect of the temperature difference cannot be canceled, and the frequency difference value based on the adsorption of the sensed substance cannot be accurately obtained, which may result in a decrease in detection accuracy.

本例の感知センサ１は、既述の軸線Ｌに対してガイド１２のテーパー面１２ｂがなす角度を６０°に設定している（図２の角度ｂ）。このようにガイド１２の角度を比較的大きくすることで、被感知物質を確実に第１の振動領域４５に吸着させることができる。一方で、感知センサ１のカバー１０の内面に黒色メッキ１４の層を設ける黒色加工を行っている。この結果、水晶振動子４に対向する天板１０ａの下面（対向面）が黒体面となり、熱の反射を抑えることができる。そのため、水晶振動子４の加熱に伴う第１、第２の振動領域４５、４６間の温度差の発生を抑制し、被感知物質の検出精度の低下を抑えることができる。 In the present embodiment, the angle of the tapered surface 12b of the guide 12 with respect to the axis L is set to 60° (angle b in FIG. 2). By making the angle of the guide 12 relatively large in this way, the substance to be sensed can be reliably adsorbed to the first vibration region 45. On the other hand, the cover 10 of the sensor 1 is blackened by providing a layer of black plating 14 on the inner surface. As a result, the underside (opposing surface) of the top plate 10a facing the quartz oscillator 4 becomes a black body surface, which can suppress heat reflection. Therefore, the occurrence of a temperature difference between the first and second vibration regions 45, 46 due to heating of the quartz oscillator 4 can be suppressed, and the deterioration of the detection accuracy of the substance to be sensed can be suppressed.

特に第２の振動領域４６に対向する領域に黒色メッキ１４の層を設けることで、第２の振動領域４６の温度の上昇を効果的に抑制し、検出精度の低下を抑えることができる。
さらに本例の感知センサ１は、第２の振動領域４６の周囲を囲むようにカバー１０の内面に壁部１３を設けている。この構成により、開口部１１から侵入した被感知物質を含むガスが第２の振動領域４６に表面に流れ込むことを抑制することができる。またこの壁部１３にも黒色メッキ１４の層を設けることでも第２の振動領域４６に対する熱反射の影響を抑えることができる。 In particular, by providing the layer of black plating 14 in the area facing the second vibrating area 46, the increase in temperature of the second vibrating area 46 can be effectively suppressed, and the deterioration of detection accuracy can be suppressed.
Furthermore, in the present embodiment, the sensor 1 is provided with a wall 13 on the inner surface of the cover 10 so as to surround the periphery of the second vibration region 46. This configuration can prevent gas containing the substance to be sensed, which has entered through the opening 11, from flowing onto the surface of the second vibration region 46. Also, by providing a layer of black plating 14 on the wall 13, the effect of heat reflection on the second vibration region 46 can be suppressed.

ここでカバー１０の内部に壁部１３を設けた構成の場合、黒色メッキ１４の層は、少なくとも壁部１３の内周面を含む、壁部１３で囲まれた領域に設ければよい。
また一般に、ガイド１２のテーパー面１２ｂ開口角度が大きくなると、天板１０ａと水晶振動子４が近くなり反射した熱の影響を受けやすくなる。この点、軸線Ｌに対し、テーパー面１２ｂの上端と下端とを結んだ直線がなす角度が４０°以上の場合には、天板１０ａの下面に黒色メッキ１４の層を設けるなどの黒色加工を行うことが好ましい。なお、黒色加工の手法は、黒色メッキ１４に限定されず、黒色塗装であってもよい。 Here, in the case where the cover 10 has a structure in which the wall portion 13 is provided inside the cover 10 , the layer of black plating 14 may be provided in the area surrounded by the wall portion 13 , including at least the inner peripheral surface of the wall portion 13 .
Generally, when the opening angle of the tapered surface 12b of the guide 12 becomes larger, the top plate 10a and the crystal unit 4 become closer, and are more susceptible to the effects of reflected heat. In this regard, when the angle between the axis L and the straight line connecting the upper and lower ends of the tapered surface 12b is 40° or more, it is preferable to perform a black processing such as providing a layer of black plating 14 on the lower surface of the top plate 10a. The method of black processing is not limited to the black plating 14, and black painting may also be used.

一方で、本例のガイド１２においては、テーパー面１２ｂの下端部に、軸線Ｌとのなす角度が４０°以下の急傾斜面１２ａを接続している。このように構成することでガイド１２の上端の開口径が大きくなりすぎることを抑制している。また、急傾斜面１２ａを設けることにより、ガイド１２の上端から下端までの高さ寸法（軸線Ｌに沿った方向の寸法）を大きくすることができ、天板１０ａと水晶振動子４との離間距離が小さくなりすぎることを抑えることができる。 On the other hand, in the guide 12 of this example, a steeply inclined surface 12a, which forms an angle of 40° or less with the axis L, is connected to the lower end of the tapered surface 12b. This configuration prevents the opening diameter at the upper end of the guide 12 from becoming too large. In addition, by providing the steeply inclined surface 12a, the height dimension from the upper end to the lower end of the guide 12 (the dimension in the direction along the axis L) can be increased, and the distance between the top plate 10a and the quartz crystal oscillator 4 can be prevented from becoming too small.

また図２を用いて説明したように、壁部１３で囲まれた領域における第２の振動領域４６と天板１０ａの下面との離間距離ｈ１が、その外部の領域における離間距離ｈ２よりも大きくなるように構成してもよい。この構成により天板１０ａの下面にて入射し、反射する熱エネルギーの減衰量を大きくすることができる。この構成によっても、水晶振動子４の加熱に伴う第１、第２の振動領域４５、４６間の温度差の発生を抑制することができる。
さらにここで、第１及び第２の発振回路９１、９２は、感知センサ１内に設けられていることは必須の要件ではない。例えば感知装置の本体部１００にこれらの発振回路９１、９２を設けてもよい。 2, the distance h1 between the second vibration region 46 and the bottom surface of the tabletop 10a in the region surrounded by the wall 13 may be greater than the distance h2 in the outer region. This configuration can increase the attenuation of the thermal energy that is incident on and reflected by the bottom surface of the tabletop 10a. This configuration can also suppress the occurrence of a temperature difference between the first and second vibration regions 45, 46 due to heating of the quartz crystal unit 4.
Furthermore, it is not essential that the first and second oscillator circuits 91, 92 are provided within the sensing sensor 1. For example, these oscillator circuits 91, 92 may be provided in the main body 100 of the sensing device.

［実施例］
天板１０ａの下面を黒色加工する効果を検証するため以下の試験を行った。
［実施例］
図１～図５を用いて説明した実施の形態に係る感知センサ１を用い実験を行った例を実施例とした。
［比較例］
カバー１０の内面に黒色メッキ１４の層を設けないことを除いて実施例１と同様に構成した感知センサを用いて実験を行った例を比較例とした。
［参照例］
またガイド１２の斜面部分を軸線Ｌに対して２０°の角度に設定したことを除いて比較例と同様に構成した感知センサを用いて実験を行った例を参照例とした。 [Example]
The following test was carried out to verify the effect of blackening the underside of the top plate 10a.
[Example]
Examples were given as examples in which experiments were conducted using the sensing sensor 1 according to the embodiment described with reference to FIGS.
[Comparative Example]
As a comparative example, an experiment was conducted using a sensor having the same structure as in Example 1, except that the black plating layer 14 was not provided on the inner surface of the cover 10.
[Reference example]
Also, as a reference example, an experiment was conducted using a detection sensor configured similarly to the comparative example, except that the inclined surface portion of the guide 12 was set at an angle of 20° with respect to the axis L.

実施例、比較例、及び参照例について各々基準温度から温度を昇温させたときの周波数差分値を測定した。図６は実施例、比較例、及び参照例の感知センサ１を用いて測定を行ったときに水晶振動子４の基準温度（－８０℃）から昇温した温度ごとに検出された周波数差分値を示す。 The frequency difference value was measured when the temperature was raised from the reference temperature for each of the working example, comparative example, and reference example. Figure 6 shows the frequency difference value detected for each temperature raised from the reference temperature (-80°C) of the quartz crystal oscillator 4 when measurements were performed using the sensing sensor 1 of the working example, comparative example, and reference example.

図６に示すように温度を５０℃上昇させたときに比較例と参照例の間で周波数差分値に差が生じ、８０℃上昇させたときに１．３ｐｐｍ程度の差が生じていた。これに対して実施例１にて取得された周波数差分値は、参照例とほぼ値が得られていた。
この結果によれば開口部１１に設置するガイド１２の開口角度を大きくすることで周波数差分値の誤差が出やすくなるが、カバー１０の内面に黒色メッキ１４の層を設けることで周波数差分値の誤差を抑制できると言える。 6, a difference occurred in the frequency difference value between the comparative example and the reference example when the temperature was increased by 50° C., and a difference of about 1.3 ppm occurred when the temperature was increased by 80° C. In contrast, the frequency difference value obtained in Example 1 was almost the same as that of the reference example.
According to these results, increasing the opening angle of the guide 12 installed in the opening 11 makes it easier for errors in the frequency difference value to occur, but it can be said that the error in the frequency difference value can be suppressed by providing a layer of black plating 14 on the inner surface of the cover 10.

１感知センサ
６ペルチェ素子部
１０カバー
１１開口部
１２ガイド
１４黒色メッキ
４５第１の振動領域
４６第２の振動領域
４０水晶片 REFERENCE SIGNS LIST 1: Sensor 6: Peltier element section 10: Cover 11: Opening 12: Guide 14: Black plating 45: First vibration area 46: Second vibration area 40: Quartz crystal piece

Claims

A sensing sensor for sensing a gaseous substance to be sensed on the basis of a relationship between a change in oscillation frequency of the piezoelectric vibrator and the temperature, comprising:
a piezoelectric vibrator including a first vibration region and a second vibration region, the first vibration region and the second vibration region being spaced apart from each other and formed so as to face each other on one side and the other side of a common piezoelectric piece, the piezoelectric vibrator being supported by a sensor substrate ;
a temperature control mechanism for controlling the temperature of the piezoelectric vibrator by heat transfer from the sensor substrate ;
a cover member that covers the piezoelectric vibrator from the one surface side,
the cover member has an opposing surface disposed so as to face the one surface of the piezoelectric vibrator at a distance from the one surface, and an opening that opens on the opposing surface so that the excitation electrodes on the one surface side constituting the first vibration region are exposed to the outside, and has a guide formed with an annular tapered surface whose opening diameter gradually increases with increasing distance from the one surface;
A black body surface that is blackened is formed on the facing surface of the cover member in an area facing the excitation electrode on the one surface side that constitutes the second vibration area;
A sensing sensor characterized in that an angle between a straight line connecting the upper and lower ends of the tapered surface of the guide and an axis perpendicular to one surface of the piezoelectric vibrator is 40° or more.

A sensing sensor for sensing a gaseous substance to be sensed on the basis of a relationship between a change in oscillation frequency of the piezoelectric vibrator and the temperature, comprising:
The piezoelectric vibrator includes a first vibration region and a second vibration region, each of which is formed by sandwiching a common piezoelectric piece and providing two sets of excitation electrodes on one surface side and the other surface side of the common piezoelectric piece so as to face each other, the first vibration region and the second vibration region being spaced apart from each other;
A temperature control mechanism for controlling the temperature of the piezoelectric vibrator;
a cover member that covers the piezoelectric vibrator from the one surface side,
the cover member has an opposing surface disposed so as to face the one surface of the piezoelectric vibrator at a distance from the one surface, and an opening that opens on the opposing surface so that the excitation electrodes on the one surface side constituting the first vibration region are exposed to the outside, and has a guide formed with an annular tapered surface whose opening diameter gradually increases with increasing distance from the one surface;
A black body surface that is blackened is formed on the facing surface of the cover member in an area facing the excitation electrode on the one surface side that constitutes the second vibration area;
the angle between a straight line connecting the upper end and the lower end of the tapered surface of the guide and an axis perpendicular to one surface of the piezoelectric vibrator is 40° or more;
a cylindrical wall portion is provided that surrounds an excitation electrode that constitutes the second vibration region from the peripheral portion of the region in which the blackbody surface is formed, and protrudes downward toward a height position close to one surface of the piezoelectric vibrator .

The sensing sensor according to claim 2, characterized in that the inner circumferential surface of the wall is a black body surface that has been blackened.

A sensing sensor for sensing a gaseous substance to be sensed on the basis of a relationship between a change in oscillation frequency of the piezoelectric vibrator and the temperature, comprising:
The piezoelectric vibrator includes a first vibration region and a second vibration region, each of which is formed by sandwiching a common piezoelectric piece and providing two sets of excitation electrodes on one surface side and the other surface side of the common piezoelectric piece so as to face each other, the first vibration region and the second vibration region being spaced apart from each other;
A temperature control mechanism for controlling the temperature of the piezoelectric vibrator;
a cover member that covers the piezoelectric vibrator from the one surface side,
the cover member has an opposing surface disposed so as to face the one surface of the piezoelectric vibrator at a distance from the one surface, and an opening that opens on the opposing surface so that the excitation electrodes on the one surface side constituting the first vibration region are exposed to the outside, and has a guide formed with an annular tapered surface whose opening diameter gradually increases with increasing distance from the one surface;
A black body surface that is blackened is formed on the facing surface of the cover member in an area facing the excitation electrode on the one surface side that constitutes the second vibration area;
the angle between a straight line connecting the upper end and the lower end of the tapered surface of the guide and an axis perpendicular to one surface of the piezoelectric vibrator is 40° or more;
A sensing sensor characterized in that the opposing surface in an area where the blackbody surface is formed is spaced farther from one surface of the piezoelectric vibrator than the opposing surface in an area where the blackbody surface is not formed .

The sensor according to any one of claims 1 to 4, characterized in that the guide is connected to the lower end of the tapered surface, has an annular steeply inclined surface with a steeper inclination than the tapered surface, and the angle between the axis and a straight line connecting the upper and lower ends of the steeply inclined surface is 40° or less.

A sensing sensor according to any one of claims 1 to 5;
an oscillation circuit that oscillates the first vibration area and the second vibration area;
A sensing device comprising: a frequency acquisition unit that acquires an oscillation frequency of the oscillation circuit.