JP2014021018A - Sensing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensing device that can sense a sensing object with high sensitivity, and can prevent increase in a physical size and a production cost.SOLUTION: A device is configured to comprise: a first oscillation circuit for outputting a first oscillation frequency by oscillating a piezoelectric oscillator in a first oscillation mode such that a first oscillatory displacement distribution is formed on the piezoelectric oscillator; a second oscillation circuit for outputting a second oscillation frequency by oscillating the piezoelectric oscillator in a second oscillation mode such that a second oscillatory displacement distribution in which only one part of a specific area is not oscillated is formed thereon; a temperature compensation part that estimates a temperature of the piezoelectric oscillator on the basis of the second oscillation frequency, and controls the first oscillation circuit such that a deviation of the first oscillation frequency based on a deviation of the estimated temperature to a reference temperature is compensated; and an absorption film provided in the specific area and for changing the first oscillation frequency by absorbing the sensing object contained in a specimen fluid.

Description

  The present invention relates to a sensing device that senses the sensing object by detecting a frequency that changes when the sensing object is adsorbed on an adsorption film formed on a piezoelectric vibrator.

  A very small amount of a sensing object is detected by a QCM (Quarts Crystal Microbalance). In this technique, an adsorption film that adsorbs and reacts with a sensing object is provided on an electrode of a crystal oscillator that is a piezoelectric vibrator, and is configured as a sensor for the sensing object. Then, the oscillation frequency of the crystal resonator decreases due to the mass addition effect caused by the adsorption reaction of the sensing object on the adsorption film. Using this change in oscillation frequency, the sensing object in the sample liquid supplied to the surface of the crystal unit is sensed.

  In this QCM, there is a case where the above-mentioned sensing is performed by using a crystal resonator formed of a crystal piece provided with a single electrode pair as a sensor, but in order to increase measurement accuracy, two electrode pairs are provided on one crystal piece. In some cases, a sensor is formed by forming two crystal resonators from the crystal piece. In that case, the adsorption film is formed on the electrodes constituting the electrode pair of one crystal resonator, and the one crystal resonator is configured to detect the sensing object. The electrode constituting the electrode pair of the other crystal unit is not provided with the adsorption film, and the crystal unit is configured as a reference crystal unit. Then, both the electrodes of each crystal resonator are exposed to the sample solution to detect the frequency difference of each crystal resonator, and this frequency difference is a crystal composed of only the adsorbed portion of the sensing object whose influence such as temperature has been canceled. The sensing device is configured to handle the frequency change amount of the vibrator. This sensing device senses a sensing object with high sensitivity.

  However, when two crystal resonators are formed on a common crystal piece as described above, it is necessary to prevent elastic coupling between the crystal resonators. For this purpose, each crystal resonator is configured so that the distance between the electrode pairs is sufficiently separated and a boundary layer such as a groove is formed between the electrode pairs of the crystal piece to suppress vibration propagation between the crystal resonators. Countermeasures are taken such as increasing the difference in output frequency from each crystal resonator by changing the thickness of the crystal piece or the film thickness of each electrode pair. However, if the distance between the electrode pairs is increased, the crystal resonator becomes larger. Further, when the boundary layer is provided or the thickness of the crystal piece and the electrode pair is changed between the crystal resonators, it takes a lot of man-hours to process the crystal resonator.

  Patent Document 1 describes a technique for separating the resonance frequency of the main vibration and the resonance frequency of the inharmonic mode in a crystal resonator. Patent Document 2 describes that a plurality of vibration modes are excited in a piezoelectric filter. However, the techniques of these Patent Documents cannot solve the above problems.

JP-A-11-205075 JP 2001-244790 A

  The present invention has been made under such circumstances, and an object of the present invention is to provide a sensing device capable of sensing a sensing object with high accuracy and simplifying the manufacturing process of a piezoelectric vibrator. Is to provide.

The sensing device of the present invention includes a piezoelectric piece having excitation electrodes formed on one side and the other side thereof, and a piezoelectric vibrator to which a sample fluid is supplied to the one side,
A first oscillation circuit for outputting the first oscillation frequency by vibrating the piezoelectric vibrator in a first vibration mode so that a first vibration displacement distribution is formed in the piezoelectric vibrator;
The piezoelectric vibrator is vibrated in the second vibration mode so that a second vibration displacement distribution is formed in which a region vibrated in the first vibration mode on one surface side of the piezoelectric piece becomes a node of vibration displacement. A second oscillation circuit for outputting a second oscillation frequency,
A switching unit that switches and connects the excitation electrode to the first oscillation circuit or the second oscillation circuit in order to switch and extract the first oscillation frequency and the second oscillation frequency.
A first adsorption film provided in the node of the vibration displacement for adsorbing a first sensing object contained in the sample fluid and changing the first oscillation frequency;
Measuring means for measuring the oscillation frequency of the first oscillation circuit and the oscillation frequency of the second oscillation circuit, and processing measurement data to detect the first sensing object based on the measurement result; Prepared,
The oscillating frequency of the second oscillating circuit is used for canceling a temperature variation included in the oscillating frequency of the first oscillating circuit.

Specific embodiments of the present invention are as follows, for example.
(A) The first vibration mode is the main vibration of the thickness shear vibration, and the second vibration mode is an inharmonic overtone.
(B) The first vibration mode and the second vibration mode are in-harmonic overtones of thickness shear vibration.
(C) The first adsorption film is provided at a position including a position where the vibration displacement in the first vibration mode is maximized.
(D) In the piezoelectric piece, a piezoelectric vibrator that is vibrated in a third vibration mode is formed outside a region that is vibrated in the first vibration mode and the second vibration mode.
A third oscillation circuit for outputting the third oscillation frequency by vibrating the piezoelectric vibrator in the third vibration mode;
A second adsorption film for adsorbing a second sensing object contained in the sample fluid and changing the third oscillation frequency,
The measurement means further includes means for measuring an oscillation frequency of a third oscillation circuit and processing measurement data to detect the second sensing object based on the measurement result. The second oscillation circuit This oscillation frequency is further used to cancel out a temperature fluctuation included in the oscillation frequency of the second oscillation circuit.
(E) The piezoelectric piece is an AT-cut crystal piece.

  In the sensing device of the present invention, the piezoelectric vibrator is switched to and connected to the first and second oscillation circuits to oscillate in the first and second vibration modes having different vibration distributions. An adsorption film for a sensing object is provided in a region that is vibrated in the second vibration mode and vibrated in the first vibration mode, and senses the sensing object based on a frequency change in the first vibration mode. The frequency of the second vibration mode is used to reduce the measurement error of the sensing object due to the temperature change of the frequency of the first vibration mode. Therefore, it is possible to measure a sensing object with high accuracy against temperature fluctuations. In addition, since there is no need to configure a plurality of piezoelectric vibrators on a common piezoelectric piece, a boundary layer such as a groove is provided on the piezoelectric vibrator, excitation electrodes of the piezoelectric vibrator are separated from each other, There is no need to adjust the thickness of the piezoelectric piece and the excitation electrode. Accordingly, it is possible to prevent the piezoelectric vibrator from being enlarged and to prevent an increase in man-hours required for processing the piezoelectric vibrator.

It is a schematic block diagram of the sensing apparatus which concerns on this invention. It is explanatory drawing which shows distribution of the vibration displacement of S0 mode of a crystal oscillator. It is a wiring diagram which shows the connection of a crystal oscillator and an oscillation circuit. It is explanatory drawing which shows distribution of the vibration displacement of A0 mode of a crystal oscillator. It is a wiring diagram which shows the connection of a crystal oscillator and an oscillation circuit. It is a wiring diagram which shows the connection of a crystal oscillator and an oscillation circuit. It is a graph which shows the relationship between the admittance of each vibration mode of a crystal oscillator, and a frequency. It is a block diagram of the said sensing apparatus. It is a graph which shows the relationship between the temperature of a crystal oscillator, and an oscillation frequency. It is a graph which shows the relationship between the control voltage of an oscillation circuit, and an oscillation frequency. It is a graph which shows that an oscillation frequency changes by adsorption | suction of a sensing target object. It is a block diagram which shows the example of another sensing apparatus. It is a block diagram which shows the example of another sensing apparatus. It is explanatory drawing which shows the vibration distribution of the side surface of another crystal oscillator, and S0 mode. It is a wiring diagram which shows the connection of the said crystal oscillator and an oscillation circuit. It is a wiring diagram which shows the connection of the said crystal oscillator and an oscillation circuit. It is explanatory drawing which shows the vibration distribution of A0 mode of a crystal oscillator. It is a wiring diagram which shows the connection of the said crystal oscillator and an oscillation circuit. It is a wiring diagram which shows the connection of the said crystal oscillator and an oscillation circuit. It is a schematic block diagram of a sensing apparatus. It is a side view of the crystal oscillator used for the sensing device. It is a wiring diagram which shows the connection of the said crystal oscillator and an oscillation circuit. It is a top view of the compound crystal oscillator which consists of said each crystal oscillator. FIG. 3 is a side view of a crystal resonator constituting the composite crystal resonator. It is explanatory drawing which shows the reaction film corresponding to the vibration mode of each said quartz oscillator, and each vibration mode. It is explanatory drawing which shows the reaction film corresponding to the vibration mode of each said quartz oscillator, and each vibration mode. It is explanatory drawing which shows the reaction film corresponding to the vibration mode of each said quartz oscillator, and each vibration mode. It is a schematic block diagram of the sensing apparatus using the said composite crystal oscillator. It is explanatory drawing which shows the other structural example of the crystal oscillator used for the said composite crystal oscillator. FIG. 10 is a top view of another composite crystal resonator. It is a schematic block diagram of the further another sensing apparatus using the said composite crystal oscillator. It is explanatory drawing which shows a response | compatibility with the reaction film and each vibration mode of the crystal oscillator which comprises the said composite crystal oscillator. It is a side view which shows the other structural example of the crystal oscillator which comprises the said composite crystal oscillator. It is the perspective view which showed typically the crystal piece of the crystal oscillator. It is a schematic diagram which shows the state which the said crystal piece vibrates in S0 mode. It is a schematic diagram which shows the state which the said crystal piece vibrates in A0 mode. It is a schematic diagram which shows the state which the said crystal piece vibrates in A1 mode. It is a schematic diagram of the vertical side surface of the crystal piece at the time of vibration in A1 mode. It is a schematic diagram of the vertical side surface of the crystal piece at the time of vibration in A1 mode.

(First embodiment)
The sensing device 1 according to the present embodiment will be described. The sensing device 1 is supplied with a sample solution, and the sensing device 1 is intended to detect the presence or absence of a sensing object contained in the sample solution, for example, to about 10 ⁻⁶ to 10 ⁻⁹ g. The sensing object is determined according to the type of reaction film described later, but here, as an example, it is configured to detect influenza virus. FIG. 1 is a schematic explanatory diagram of the sensing device 1. As shown in FIG. 1, the sensing device 1 includes a sensor unit 2, an oscillation control unit 4, and a data processing unit 6.

  The sensor unit 2 includes a crystal resonator 3 and is a unit to which the sample solution is supplied. The oscillation control unit 4 is a unit that controls the oscillation of the crystal unit 3 and outputs the oscillation in the S0 mode described later to the subsequent stage. The data processing unit 6 is a unit for displaying the oscillation frequency output from the oscillation control unit 4 so that the user of the sensing device 1 can detect the virus.

  The sensor unit 2 will be described in detail. The sensor unit 2 includes the crystal resonator 3 having a rectangular shape in plan view, a substrate 22 that supports the crystal resonator 3, and a unit main body 23 that surrounds the substrate 22 and the crystal resonator 3. The unit main body 23 includes a unit upper part 23A and a unit lower part 23B. The unit lower part 23B is provided with a recess 24, and a step 25 is formed in the recess 24, and the recess 24 is formed narrower on the lower side than on the upper side. The peripheral portion of the substrate 22 is supported on the step portion 25. The substrate 22 is provided with a through hole 22A, and the peripheral portion of the crystal unit 3 is supported on the substrate 22 so as to close the through hole 22A.

  A flow path forming member 26 made of a plate-like elastic member is provided in the concave portion 24 so as to cover the upper part of the crystal resonator 3. The flow path forming member 26 includes a liquid circulation space 27 that forms a recess on the lower side thereof. The unit upper portion 23A is provided on the unit lower portion 23B so as to close the recess 24, and presses and fixes the peripheral portion of the crystal resonator 3 to the step portion 25 through the flow path forming member 26. Further, a sample liquid supply path forming member 28 and a waste liquid path forming member 29 are provided in the unit upper portion 23A. These forming members 28 and 29 are provided with a flow path for the sample solution communicating with the circulation space 27.

  Before supplying the sample liquid, the sensor unit 2 is supplied with a reference liquid in order to prevent fluctuations in the oscillation frequency of the crystal unit 3 due to the liquid pressure when the sample liquid is supplied. The reference liquid does not include a sensing object. A pump and a valve (not shown) are provided on the upstream side of the supply path forming member 28, and the reference liquid and the sample liquid are switched to each other and supplied to the circulation space 27 through the flow path of the supply path forming member 28. Thus, the surface of the crystal unit 3 can be circulated in the length direction. The liquid supplied to the distribution space 27 is pushed out into the flow path of the waste liquid path forming member 29 by the liquid supplied to the distribution space 27 later and is discharged.

  The oscillation control unit 4 is connected to the crystal resonator 3 that is a piezoelectric resonator. The oscillation control unit 4 includes a first oscillation circuit 401 and a second oscillation circuit 402 so that the crystal resonator 3 can be switched and oscillated in an S0 mode and an A0 mode, which will be described later. The first oscillation circuit 401 is configured to be able to oscillate in the S0 mode, and the second oscillation circuit 402 is configured to be able to oscillate in the A0 mode.

  FIG. 2 is a side view of the crystal unit 3. The crystal unit 3 includes an AT-cut crystal piece 31. In the AT-cut crystal piece 31, the main surface (YZ plane) is inclined 35 degrees 15 minutes from the Z axis to the Y axis with respect to the Y axis, which is the crystal axis of the crystal. In each figure, the width direction, the thickness direction, and the length direction of the crystal piece 31 cut in this way are shown as an X-axis direction, a Y′-axis direction, and a Z′-axis direction, respectively. That is, the Y ′ axis and the Z ′ axis are axes inclined by about 35 degrees with respect to the Y axis and the Z axis, respectively. Excitation electrodes 301 and 303 are provided on the surface (upper surface) of the crystal piece 31 so as to be separated from each other in the length direction, and the excitation electrodes 302 and 304 are provided on the back surface (lower surface) of the crystal piece 31. Provided. The electrodes 301 and 302 are formed so as to overlap each other, and the electrodes 303 and 304 are formed so as to overlap each other. In practice, a connection electrode is formed from the electrodes 301 to 304 toward the periphery of the crystal piece 31, and the connection electrode is connected to a conductive path provided on the substrate 21. The electrodes 301 to 304 are electrically connected to the oscillation control unit 4 through this conductive path.

  A reaction film 311 is formed between the electrodes 301 and 303 at the center in the length direction of the surface of the crystal piece 31. The reaction membrane 311 includes an antibody that uses the influenza virus, which is a sensing object, as an antigen, and forms an adsorption membrane that specifically adsorbs the virus by an antigen-antibody reaction. The crystal unit 3 is provided in the sensor unit 2 so that the electrodes 302 and 304 and the reaction film 311 face the circulation space 27. The electrodes 302 and 304 are configured to face the through hole 22 </ b> A of the substrate 22.

  By switching the wiring between the electrodes 301 to 304 of the crystal unit 3 and the oscillation circuits 401 and 402, the crystal unit 3 can oscillate in the S0 mode or the A0 mode. The S0 mode is the main vibration of the thickness shear vibration and is used for sensing the sensing object. FIG. 2 shows the distribution of vibration displacement in the crystal unit 3. This displacement distribution graph shows that the vibration displacement decreases as the distance from the central portion of the crystal unit 3 in the horizontal direction (Z′-axis direction) increases, and the center of the crystal unit in the horizontal direction (Z′-axis direction). It is shown that the vibration displacement increases (becomes a vibration antinode) as it approaches. When the vibration distribution of each other mode is shown later, it is shown in the same manner as this S0 mode.

  The vibration distribution in the S0 mode will be described. When the crystal piece 31 is viewed from the lateral direction, the central portion between the electrodes has a relatively large vibration, and the vibration decreases from the central portion toward each electrode. In other words, the reaction film 311 in the crystal piece 31 is provided at a portion where the vibration displacement becomes maximum, that is, a so-called vibration antinode. As a result, the oscillation frequency in the S0 mode changes relatively largely due to the mass addition effect caused by the adsorption of the sensing object to the reaction film 311, so that high detection sensitivity can be obtained.

  FIG. 3 shows wiring for oscillating the crystal unit 3 in the S0 mode. As shown in FIG. 3, the electrodes 301 and 303 on the upper side of the crystal piece 31 are connected to each other, and these electrodes 301 and 303 are connected in series to one of the input side and the output side of the first oscillation circuit 401. It is connected. The lower electrodes 302 and 304 of the crystal piece 31 are connected to each other, and these electrodes 302 and 304 are connected in series to the other of the input side and the output side of the first oscillation circuit 401.

  Next, the A0 mode will be described. This A0 mode is an inharmonic overtone of thickness-shear vibration and is used to detect the temperature of the crystal unit 3. FIG. 4 shows the distribution of vibration displacement in the A0 mode in the crystal unit 3. As shown in FIG. 4, this vibration displacement is observed when the crystal piece 31 is viewed from the lateral direction, and a central portion between the electrodes 301 and 302 is a node of vibration displacement, and as the crystal piece 31 moves toward the electrode 301 side and the 303 side. The vibration displacement gradually increases. The electrodes 301 and 303 vibrate in opposite directions in the X-axis direction of the crystal piece 31 (direction perpendicular to the paper surface in FIG. 4). The vibration displacement becomes maximum on the electrodes 301 and 303, and gradually decreases as the crystal piece 31 is moved outward. That is, the central part of the crystal piece 31 provided with the reaction film 311 becomes a node of vibration displacement, and vibration does not occur. Due to this vibration displacement distribution, the crystal unit 3 oscillates in the A0 mode without being affected by the adsorption between the reaction film 311 and the sensing object.

  By connecting the crystal unit 3 to the second oscillation circuit 402 as shown in FIG. 5 or FIG. 6, the crystal unit 3 can be oscillated in the A0 mode. In the example shown in FIG. 5, the electrodes 301 and 304 are connected to each other, and the electrodes 301 and 304 are connected in series to one of the input side and the output side of the second oscillation circuit 402. The electrodes 303 and 302 are connected to each other, and the electrodes 303 and 302 are connected in series to the other of the input side and the output side of the second oscillation circuit 402. In the example shown in FIG. 6, the electrodes 302 and 304 are connected to each other, and the electrodes 301 and 303 are connected in series to the input side and the output side of the second oscillation circuit 402, respectively. Although not shown, in each figure, for example, the upper electrodes 301 and 303 of the crystal piece 31 are grounded.

  The S0 mode and the A0 mode will be further described with reference to FIG. FIG. 7 is a graph of each mode in which frequency is set on the horizontal axis and admittance is set on the vertical axis. The A0 mode is excited at a frequency near the S0 mode, and the resonance frequency and antiresonance frequency of the A0 mode are higher than the resonance frequency and antiresonance frequency of the S0 mode. Note that the S1 mode not used in the first embodiment is also shown in FIG. 7, but this S1 mode will be described later.

  Subsequently, the description of the sensing device 1 will be continued with reference to FIG. 8 showing the configurations of the oscillation control unit 4 and the data processing unit 6 in detail. The oscillation control unit 4 includes the oscillation circuits 401 and 402, the connection switching unit 41, the frequency measurement units 411 and 412, the temperature estimation unit 43, the temperature compensation voltage calculation unit 44, and the addition unit 45. Yes. The first oscillation circuit 401 and the second oscillation circuit 402 are provided in the subsequent stage of the connection switching unit 41. The temperature estimation unit 43, the temperature compensation voltage calculation unit 44, and the addition unit 45 constitute a temperature compensation unit.

In order to explain the role of the oscillation control unit 4, the frequency temperature characteristics of an AT-cut crystal resonator will be described as an example with reference to FIG. In FIG. 9, the vertical axis of the graph represents a target frequency (f ₀ ) to be set when the sensing object is not adsorbed on the reaction film 311 (desired to oscillate), a frequency f actually obtained at the temperature T, (Δf / f ₀ , Δf = f−f ₀ ), and the horizontal axis represents the temperature T of the crystal unit 3. T ₀ is a reference temperature, for example, 29 ° C., and the control voltage of the first oscillation circuit 401 is set so that the set frequency f ₀ is obtained at this temperature T ₀ . When oscillation is performed using the AT-cut crystal piece 31, the frequency deviation Δf / f ₀ is approximated by the equation (1) that is a cubic function of the temperature T.
Δf / f ₀ = α (T−T ₀ ) ³ + β (T−T ₀ ) + γ (1)
In the equation (1), α, β, and γ are constants obtained individually for each crystal resonator.

As described above, since the oscillation frequency of the S0 mode changes depending on the temperature of the crystal piece 31, the frequency of the S0 mode changes depending on both the adsorption to the reaction film 311 and the temperature change of the crystal unit 3. Although not shown, the oscillation frequency also changes in accordance with the temperature of the crystal unit 3 in the A0 mode. Therefore, the oscillation control unit 4 detects the temperature from the oscillation frequency of the A0 mode, and a frequency deviation Δf from the set frequency f ₀ due to the deviation between the reference temperature T ₀ and the temperature is determined according to the detected temperature. as compensation, it controls the control voltage V _c supplied to the first oscillator circuit 401. The oscillation frequency f of the first oscillation circuit 401 is proportional to the control voltage V _c as shown in FIG. 10. That is, the oscillation frequency in the A0 mode is used for reference with respect to temperature, and the oscillation frequency in the S0 mode is used for detection of a sensing object using the oscillation frequency in the A0 mode.

  Returning to the description of FIG. In the connection switching unit 41, the electrodes 301 to 304 and the first oscillation circuit 401 are connected as shown in FIG. 3, and the electrodes 301 to 304 and the second oscillation circuit 402 are connected as shown in FIG. Are switched to each other. As a result, the oscillation frequencies of the S0 mode and the A0 mode are alternately extracted in time division from the first oscillation circuit 401 and the second oscillation circuit 402, respectively. Each connection state is switched at a high speed, so that these oscillation frequencies are output substantially simultaneously. In order to take out the oscillation output of the A0 mode, the connection switching unit 41 may be configured so that the wiring is formed as shown in FIG. 6 instead of the wiring as shown in FIG.

Incidentally, 51 in FIG. 8 is a reference voltage supply terminal of the first oscillation circuit 401. It represents a reference voltage as V ₀ in FIG. Reference voltage V ₀ is input to the adder 45, the control voltage V _c is calculated on the basis of the reference voltage V _0. The first oscillation circuit 401 is connected varicap diode 52 is grounded, the control voltage V _c via the varicap diode 52 is applied to the first oscillator circuit 401, the oscillation frequency is controlled. The addition unit 45 will be further described. The temperature compensation voltage ΔV calculated based on the output of the second oscillation circuit 402 is subtracted from the reference voltage V ₀ as shown in the following equation (2) (the sign of ΔV is taken). by said to addition) by person, and is configured so that the control voltage V _c is generated.
V _c = V ₀ −ΔV (2)

The reference voltage V ₀ is a control voltage when the set frequency f ₀ is output from the first oscillation circuit 401 at a reference temperature T _0, for example, 29 ° C. Incidentally, the oscillation frequency f of the first oscillation circuit 401 as described above is proportional to the control voltage V _c. Since it is in such a proportional relationship, the temperature compensation voltage ΔV is expressed as in equation (3), and since equation (4) holds, ΔV is expressed as in equation (5). Incidentally, T is the temperature detected in the temperature estimating unit 43, a Δf = _{f-f 0.}
ΔV = V ₀ (Δf / f ₀ ) (3)
Δf / f ₀ = α ₁ (T−T ₀ ) ³ + β ₁ (T−T ₀ ) + γ ₁ (4)
ΔV = V ₀ {α ₁ (T−T ₀ ) ³ + β ₁ (T−T ₀ ) + γ ₁ } (5)
α ₁ , β ₁ and γ ₁ are constants inherent to the first oscillation circuit 401. The frequency measurement unit 411 is provided at the subsequent stage of the first oscillation circuit 401. The frequency measuring unit 411 includes a frequency counter, measures the oscillation frequency f of the first oscillation circuit 401, and outputs data of the measured value to the data processing unit 6.

In the figure, reference numeral 53 denotes a terminal for supplying the control voltage V ₁₀ to the second oscillation circuit 402. A grounded varicap diode 54 is connected to the second oscillation circuit 402, and the control voltage V ₁₀ is supplied from the voltage supply terminal 53 to the second oscillation circuit 402 via the varicap diode 54. . In addition, the frequency measurement unit 412, the temperature estimation unit 43, and the temperature compensation voltage calculation unit 44 are connected to the second oscillation circuit 402 in this order.

  The frequency measuring unit 412 is constituted by a frequency counter, for example, and outputs the measured frequency to the temperature estimating unit 43. The temperature estimation unit 43 stores a correspondence relationship (temperature characteristic) between the frequency measured by the frequency measurement unit 412 and the temperature of the crystal unit 3 in advance. Based on the temperature characteristics and the oscillation frequency output from the frequency measuring unit 412, the temperature estimating unit 43 estimates the temperature T of the crystal unit 3, and a signal corresponding to the temperature T is output to the subsequent stage. Further, the compensation voltage calculation unit 44 obtains the temperature compensation voltage ΔV based on the above-described equation (5) and the temperature T, and this ΔV is output to the above-described addition unit 45.

The oscillation frequency f of the first oscillation circuit 401 is proportional to the control voltage V _c as described above. Accordingly, when the temperature is changed from T ₀ to T ₁ , the temperature compensation voltage calculation unit 44 compensates for Δf, which is the difference between the frequency f ₁ and the set frequency f ₀ , by the compensation voltage ΔV corresponding to Δf. It is controlled so as to increase the control voltage V _c. Temperature compensation voltage ΔV can be obtained by substituting the temperature T ₁ of the temperature T of the equation (5). As a result, the oscillation frequency f of the first oscillation circuit 401 tends to be increased by Δf due to the influence of temperature, and the action of decreasing the oscillation frequency f by Δf due to the temperature T ₁ is canceled. When sensing target to the reaction membrane 311 thereby it is not adsorbed would oscillation frequency f is maintained at the set frequency f _0.

  Next, the data processing unit 6 that is a computer will be described. In FIG. 8, reference numeral 61 denotes a bus to which the frequency measuring unit 411 is connected. The bus 61 is connected to a CPU 62, a frequency storage unit 63, and a display unit 64. The frequency storage unit 63 stores the frequency data output from the frequency measurement unit 411 in time series. The display unit 64 displays the change of the frequency over time based on the data stored in the frequency storage unit 63. A display example will be described later. In the figure, reference numeral 65 denotes a program, and the program 65 and the CPU 62 control the operation of the data processing unit 6 such as the storage operation and the display operation.

  Next, the operation of the above-described sensing device 1 will be described. FIG. 11 is a graph showing how the frequency f output from the first oscillation circuit 401 changes, and will be described with reference to this graph. The vertical axis of this graph represents frequency, and the horizontal axis represents time. Such a graph is displayed on the display unit 64 so that the user of the apparatus can grasp the change in frequency. The power supply (not shown) of the apparatus is turned on, and the crystal unit 3 is alternately connected to the first oscillation circuit 401 and the second oscillation circuit 402 by the switching unit 41, and the S0 mode and the A0 mode are switched to each other. Is output.

The temperature estimation unit 43 estimates the temperature of the crystal unit 3 from the oscillation frequency in the A0 mode, and the temperature compensation voltage calculation unit 44 outputs the compensation voltage ΔV so as to obtain the oscillation frequency f ₀ of the reference temperature T _0. V _c = V ₀ −ΔV is output to the first oscillation circuit 401, and the oscillation frequency of the S0 mode is maintained at f ₀ . Subsequently, a reference liquid made of pure water, for example, is supplied from the supply path forming member 28 of the sensor unit 2 to the circulation space 27. As described above, the reference solution does not contain the influenza virus that is the sensing object. The oscillation frequency of the first oscillation circuit 401 decreases due to the mass impossibility of the reference liquid (time t1 in FIG. 11). The oscillation frequency thus reduced is indicated by f0 ′ in the graph. The reference liquid flows from the circulation space 27 into the waste liquid path forming member 29 and is drained.

  Subsequently, the flow path is switched on the upstream side of the supply path forming member 28 to supply the sample liquid to the supply path forming member 28 (time t2 in FIG. 11), and the sample liquid enters the flow space 27 following the reference liquid. Then, the inside of the circulation space 27 is replaced with the sample solution from the reference solution. The case where the virus is included in the sample solution will be described. When the sample solution passes through the circulation space 27, the virus is adsorbed to the reaction film 311 and the oscillation frequency of the S0 mode is lowered due to the mass addition effect. . As described above, since the reaction film 311 is provided in the central portion between the electrodes 301 and 303 having large vibrations, the adsorption causes a relatively large decrease in oscillation frequency from f0 ′.

  The central portion where the reaction film 311 is provided as described above does not vibrate due to the A0 mode, and the oscillation frequency of the A0 mode does not change due to the adsorption. Accordingly, by continuing to output the oscillation frequency of the A0 mode corresponding to the temperature of the crystal unit 3 with high accuracy, the first oscillation circuit 401 with high accuracy according to the temperature change from the reference temperature of the crystal unit 3. The deviation of the temperature change of the oscillation frequency from is compensated. Thereby, the amount of adsorbed virus corresponds to the amount of decrease from the oscillation frequency f0 'with high accuracy. In the graph, a stable frequency that has decreased from f0 'after time t2 is shown as f1.

  When the influenza virus is not contained in the sample solution, the frequency f0 'hardly changes after time t2. That is, the frequency f1 after time t2 is substantially equal to f0 '. The user reads the difference between the frequencies f0 ′ and f1 from the graph, and if the difference is greater than or equal to a preset reference value, influenza virus is contained in the sample solution, and if the difference is smaller than the reference value, influenza virus is contained in the sample solution. It is determined that it is not included. By the way, a correspondence relationship between the difference value between the frequencies f0 'and f1 and the mass of the virus may be obtained in advance by experiments, and the mass of the virus may be obtained from the difference value read from the graph as described above. That is, the sensing device 1 can sense and quantify the sensing object.

According to this sensing device 1, the common crystal unit 3 is alternately connected to the first oscillation circuit 401 and the second oscillation circuit 402 by the connection switching unit 41 so that the crystal unit 3 is in the S0 mode and the A0 mode. And the reaction film 311 is placed at the node of the vibration of the A0 mode, and the oscillation by the S0 mode is used for detection of an object to be detected on the reaction film 311 of the crystal unit 3, and the oscillation by the A0 mode is performed. Is used for detecting a change in temperature of the crystal unit 3 and correcting the output frequency in the S0 mode. As a result, the S0 mode oscillates so as not to be affected by the temperature. Therefore, the amount of decrease in the oscillation frequency corresponds to the amount of adsorption of the sensing object with high accuracy. Can be done. Further, the crystal resonators are formed in different regions of the crystal piece 31 described in the section of the background art, and only one of the crystal resonators is provided with an adsorption film, based on the difference in the oscillation frequency of each crystal resonator. Therefore, it is not necessary to prevent the elastic coupling of each crystal resonator as compared with the case where the sensing object is detected. Accordingly, it is not necessary to form a boundary layer such as a groove in the crystal piece 31 or to greatly separate the electrode pair, so that the crystal unit 3 can be reduced in size, so that the sensing device 1 is increased in size. Can be prevented. In addition, it is not necessary to form a boundary layer on the crystal piece 31 as described above, or to perform processing so that the thickness of the crystal piece and the thickness of the electrode are different for each crystal resonator. Therefore, the manufacturing cost of the sensing device 1 can be suppressed.
In the above example, the frequency measurement units 411 and 412 are used for the oscillation circuits 401 and 402, respectively. However, the frequency measurement unit is shared (one frequency measurement unit is used), and the oscillation circuits 401 and 402 are switched by a switch. The oscillation frequency may be alternately taken into the frequency measuring unit.
In the above description, the oscillation frequency of the second oscillation circuit 402 is used to cancel out the temperature variation included in the oscillation frequency of the first oscillation circuit 401. As one aspect, In the embodiment, the oscillation frequency of the A0 mode (the oscillation frequency of the second oscillation circuit 402) is handled as a temperature detection value, and a compensation value for the set value of the control voltage of the first oscillation circuit 401 is obtained based on this temperature detection value. ing.
However, the oscillation frequency of the A0 mode is not limited to this method as a usage for canceling the temperature variation included in the oscillation frequency of the S0 mode. For example, a difference between the oscillation frequency of the S0 mode and the oscillation frequency of the A0 mode may be obtained, and the sensing object may be sensed based on the difference frequency. In this case, the sensing object is adsorbed by the adsorption film, so that the oscillation frequency of the S0 mode is lowered, but the oscillation frequency of the A0 mode is not lowered. Therefore, the difference frequency changes when the sensing object is adsorbed on the adsorption film, and the amount of adsorption of the sensing object can be obtained based on the change. When the oscillation frequency of the S0 mode changes due to a temperature change, the oscillation frequency of the A0 mode also fluctuates with the same tendency. Therefore, by taking the difference between the two, the influence of the temperature change on the measurement result can be suppressed. Even in the case where the difference between the two oscillation frequencies is measured and the sensing object is sensed based on the difference frequency as in this case, in this specification, “the oscillation frequency of the first oscillation circuit 401 and the second oscillation frequency” It corresponds to the step “measure the oscillation frequency of the oscillation circuit 402 and based on the measurement result”.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. In the second embodiment, the wiring from the crystal unit 3 to the oscillation circuits 401 and 402 is different from that in the first embodiment. The connection between the oscillation circuits 401 and 402 is switched by switches 71 and 72 that form a connection switching unit. Further, this wiring will be described. The electrodes 302 and 304 are connected to each other, and the electrode 301 is short-circuited to the electrodes 302 and 304 without being grounded. These electrodes 301, 302, and 304 are connected in series to one of the oscillation circuits 401 and 402 by switching the switch 71. Further, the electrode 303 is connected in series to either one of the oscillation circuits 401 and 402 by switching the switch 72. The switches 71 and 72 are switched in synchronization, and the electrodes 301 to 304 are simultaneously connected to the oscillation circuit 401 or 402.

As in the first embodiment, when each electrode is connected to the first oscillation circuit 401, it oscillates in the S0 mode, and when each electrode is connected to the second oscillation circuit 402, it oscillates in the A0 mode. That is, the wiring from the switches 71 and 72 to the electrodes is shared during each S0 mode oscillation and A0 mode oscillation. In the second embodiment, in addition to obtaining the same effect as that of the first embodiment, the wiring can be simplified and the manufacturing cost of the device can be further reduced.

(Third embodiment)
FIG. 13 shows a third embodiment configured substantially the same as the second embodiment. In the third embodiment, one non-divided electrode 305 is provided so as to face the electrodes 302 and 304 instead of the electrodes 301 and 303. The electrode 305 is grounded. On the electrode 305, the reaction film 311 is provided at the center between the electrodes 302 and 304. Although the oscillation control unit 4 is shown with some components omitted in the figure, it is configured in the same manner as in the second embodiment, and the crystal unit 3 is connected to the oscillation circuit 401 or 402 via the switches 71 and 72. Connected to.

  Even if the crystal resonator is configured as described above, the vibration distributions in the S0 mode and the A0 mode are the same as those in the first and second embodiments. Therefore, the same effect as the first embodiment can be obtained. In addition, as in the second embodiment, the wiring from the electrodes 305, 302, 304 to the switches 71, 72 is shared in the S0 mode and the A0 mode, so that there is an advantage that the configuration of the apparatus is simplified. Further, in the crystal unit 3, if the electrodes 301 and 303 are separated from each other on the upper side of the crystal piece 31 if they are electrically separated from each other, the electrode 305 is provided on the lower side so as to face these electrodes, The electrodes 301 and 303 may not be grounded, and the electrode 305 may be grounded. The reaction film is provided between the electrodes 301 and 303 as in the first embodiment.

(Fourth embodiment)
In the fourth embodiment, a crystal resonator 300 is used instead of the crystal resonator 3. As shown in FIG. 14, the crystal resonator 300 includes three pairs of excitation electrodes formed apart from each other in the length direction of the crystal piece 31. The electrodes constituting each electrode pair are opposed to each other on the front and back of the crystal piece 31, and three electrodes 321, 323, and 325 are sequentially arranged in the length direction on the surface side of the crystal piece 31. And the electrode of the back side is shown as 322, 324, 326 along the same length direction. An electrode 323 is provided at the center between the electrodes 321 and 325, and an electrode 324 is provided at the center between the electrodes 322 and 326. The front electrodes 321, 323, and 325 are each grounded. As described above, even when three electrode pairs are formed on the crystal piece 31, oscillation can be performed in the S0 mode or the A0 mode as in the above-described embodiments.

  FIG. 14 shows the vibration distribution of the S0 mode in the crystal unit 300. This vibration distribution is the same as the vibration distribution of the quartz crystal resonator 3, and the reaction film 321 is provided on the electrode 323 where the vibration in the S0 mode is maximized. FIG. 15 shows wiring between the crystal resonator 300 and the first oscillation circuit 401 for vibrating in the S0 mode. As shown in this figure, the electrodes 321, 323, and 325 are connected to each other and these electrodes are connected in series to the first oscillation circuit 401. In addition, the electrodes 322, 324, and 326 are connected to each other and these electrodes are connected in series to the first oscillation circuit 401. FIG. 16 shows wiring different from the example shown in FIG. 15 for oscillating in the S0 mode. In the example shown in FIG. 16, only the electrodes 323 and 324 are connected to the input side and the output side of the first oscillation circuit 401, respectively.

  FIG. 17 shows the vibration displacement distribution in the A0 mode. This vibration displacement distribution is the same as the vibration displacement distribution of the quartz crystal resonator 3 and becomes a node of vibration displacement at the center between the electrodes 321 and 325 where the reaction film 311 is provided. 18 and 19 show wiring between the crystal resonator 300 and the second oscillation circuit 402 for vibrating in the A0 mode. In the example shown in FIG. 18, the electrodes 321 and 326 are connected to each other, and these electrodes 321 and 326 are connected to the second oscillation circuit 402 in series. The electrodes 322 and 325 are connected to each other, and these electrodes 322 and 325 are connected in series to the second oscillation circuit 402. In the example shown in FIG. 19, the electrodes 322 and 326 are connected to each other, and the electrodes 321 and 325 are respectively connected to the second oscillation circuit 402 in series.

  This crystal resonator 300 can be applied to the sensing device 1 of the first embodiment. In that case, in order to allow the crystal unit 300 to oscillate alternately in the S0 mode and the A0 mode, either one of the connection states of FIGS. 15 and 16 and any of FIGS. The connection switching unit 41 is configured so that one connection state is switched to each other. Thereby, measurement can be performed in the same manner as in the first embodiment.

  FIG. 20 shows an application example of the crystal unit 300 to the sensing device 1. In this example, switches 73 and 73 are interposed between the first oscillation circuit 401 and the electrodes 323 and 324, and switches 74 and 74 are interposed between the electrodes 321 and 325. Each switch 73 and 74 switches the connection between the state shown in FIG. 16 and the state shown in FIG. That is, the switches 73 and 74 correspond to the connection switching unit 41. Since the electrodes connected to the oscillation circuits 401 and 402 in the crystal resonator 300 are different from each other, the number of necessary switches can be suppressed, and the device configuration can be simplified.

(Fifth embodiment)
The crystal unit 300 can oscillate in the S1 mode. This S1 mode is an inharmonic overtone of thickness shear vibration, and its resonance frequency and antiresonance frequency are larger than each resonance frequency and antiresonance frequency of the S0 mode and A0 mode as shown in the graph of FIG. . FIG. 21 shows the vibration distribution in the S1 mode. As shown in FIG. 21, the vibration distribution in the S1 mode is maximized on the electrode 323, and thus the frequency greatly changes due to the adsorption of the sensing object to the reaction film 311 provided on the electrode 323. That is, as in the S0 mode, the central portion between the electrodes 321 and 325 provided with the reaction film 311 is an antinode of vibration. Further, the crystal displacement of the crystal piece 31 from the electrode 323 toward the electrodes 321 and 325 decreases accordingly, and when the crystal piece 31 reaches the electrodes 321 and 325, it becomes a node of vibration displacement, and further, the crystal piece 31 vibrates when going outward. The direction is opposite to that on the electrode 323. The fifth embodiment differs from the fourth embodiment in that the crystal unit 300 is oscillated in the S1 mode instead of the S0 mode.

FIG. 22 shows wiring for causing the crystal unit 300 to oscillate in the S1 mode. In order to perform oscillation in the S1 mode, the crystal resonator 300 is connected to the third oscillation circuit 403. This connection will be described. The electrodes 321, 325, and 324 are connected to each other, and these electrodes are connected in series to one of the input side and the output side of the third oscillation circuit 403. The electrodes 322, 323, and 326 are connected to each other, and these electrodes are connected in series to the other of the input side and the output side of the third oscillation circuit 403. When the crystal resonator 300 according to the fifth embodiment is applied to the sensing device 1 according to the first embodiment, the connection switching unit 41 is configured to connect the crystal resonator 300 to the oscillation circuit 401 or 403 for switching. The That is, the connection state of FIG. 15 and the connection state of FIG. 18 or FIG. 19 are configured to be switched to each other.
Also in the embodiments described so far, as described in the last part of the first embodiment, the difference between the oscillation frequency of the S0 mode and the oscillation frequency of the A0 mode is obtained and sensing is performed based on the difference frequency. An object may be detected.

(Sixth embodiment)
In the sixth embodiment, the crystal unit 3 and the crystal unit 300 are combined to use a resonator formed on a common crystal piece 31. The crystal units 3 and 300 are collectively referred to as a composite crystal unit 7. FIG. 23 shows the surface (upper surface) of the composite crystal resonator 7. X in the figure indicates the X-axis direction of the crystal of the crystal piece 31, and the crystal resonators 3 and 300 are arranged in the X-axis direction. In the figure, Z ′ indicates an orientation inclined by about 35 degrees from the Z axis of the crystal. The crystal resonators 3 and 300 in the figure oscillate individually.

  In the sixth embodiment, the crystal resonator 300 is oscillated in the S0 mode, the A0 mode, and the S1 mode as described above, and the crystal resonator 3 is oscillated in the S0 mode and the A0 mode as described above. Since they are formed on the common crystal piece 31, the crystal resonators 3 and 300 have the same temperature. Therefore, in the sensing device 1 to which the composite crystal resonator 7 is applied, the temperature of the crystal resonators 3 and 300 is estimated based on the A0 mode of the crystal resonator 3 as described in the first embodiment, Based on the temperature, the oscillation frequency of the A0 mode of the crystal unit 3 and the oscillation frequency of each of the three oscillation modes of the crystal unit 300 are controlled so that the deviation due to the temperature change from the reference temperature is compensated. Then, four types of sensing objects in the sample liquid are detected by monitoring changes in the oscillation frequency in which variations due to temperature changes are compensated. That is, the crystal resonator 300 is formed outside the region where the crystal resonator 3 is formed in the crystal piece 31, and the output of the A0 mode of the crystal resonator 3 is controlled in addition to the S0 mode oscillation control of the crystal resonator 3. Also used for oscillation control in each mode of the crystal unit 300. Each oscillation circuit that oscillates the crystal resonator 300 in each mode corresponds to a third oscillation circuit.

  In order to perform detection as described above, four types of reaction films 311, 312, 313, and 314 that adsorb different sensing objects are provided on the surface of the composite crystal resonator 7. FIG. 24 is a side view of the composite crystal resonator 7 as viewed from the crystal resonator 300 side. The reaction film 311 is provided on the electrode 323 described in the above-described embodiment. The reaction film 312 is provided between the electrodes 321 and 323 and between the electrodes 323 and 325. The reaction film 313 is provided on the electrodes 323 and 325. The reaction film 314 is provided instead of the reaction film 311 between the electrodes 301 and 303 in the crystal resonator 3 where the reaction film 311 is provided in the first embodiment.

  A method for detecting each sensing object corresponding to the reaction films 311 to 313 will be described with reference to FIGS. These figures show a reaction film on which a sensing object is adsorbed and a vibration mode in which the frequency is largely changed by the adsorption. When the sensing object is adsorbed to the reaction film 311 as shown in FIG. 25, the antinodes of vibrations in the S0 mode and the S1 mode have electrodes 321 and 325 provided with the reaction film 311 as described in each embodiment. Therefore, the oscillation frequency in the S0 mode and the S1 mode is greatly reduced. However, since the portion where the reaction film 311 is provided is a node of vibration of the A0 mode of the crystal resonator 300, the oscillation frequency of the A0 mode does not decrease.

  As shown in FIG. 26, when the sensing object is adsorbed to the reaction film 312, the reaction film 312 is provided near the antinode of the vibration of the S0 mode, so that the oscillation frequency of the S0 mode is relatively reduced. . However, since the reaction film 312 is provided near the vibration nodes of the A0 mode and the S1 mode, the oscillation frequencies of the A0 mode and the S1 mode are only slightly reduced.

  As shown in FIG. 27, when the sensing object is adsorbed to the reaction film 313, the reaction film 313 is provided near the antinodes of vibrations in the A0 mode and the S1 mode. Is relatively large. However, since this reaction film 313 is provided at a position away from the antinode of the S0 mode, the oscillation frequency of the S0 mode is only slightly reduced.

  As described above, in the crystal unit 300, each vibration mode shows different frequency changes depending on which reaction film the sensing object is adsorbed to, so that the sensing object in the sample liquid is detected based on this frequency change. Can do. Further, when the sensing object is adsorbed to the reaction film 314 of the crystal unit 3, as described in the first embodiment, the oscillation frequency of the same crystal unit 3 in the A0 mode is not changed and S0 is not changed. Mode oscillation frequency decreases.

  By the way, when a substance that reacts with only one of the reaction films 311 to 313 is included in the sample liquid, detection can be performed based on the frequency change in each mode as described above. Considering the case where the sensing object is adsorbed to each of the reaction films 311 and 312, both the frequencies of the S0 mode and the S1 mode decrease, and the frequency of the A0 mode hardly changes. As described above, the frequency of the S0 mode and the S1 mode also decreases when the sensing object is adsorbed only on the reaction film 311, but when the sensing object is adsorbed on both of the reaction films 311 and 312, Since the frequency is affected by the adsorption of both of the reaction films 311 and 312, the decrease in the frequency of the S0 mode is larger than when the sensing object is adsorbed only on the reaction film 311. Accordingly, it is possible to identify whether only the sensing object to be adsorbed on the reaction film 311 is included or whether a plurality of sensing objects to be adsorbed on the reaction films 311 and 312 are included. However, when the sensing objects are adsorbed on the reaction films 311 and 313 and when the sensing objects are adsorbed on the reaction films 312 and 313, the oscillation frequencies of the S0 mode, A0 mode, and S1 mode are all Since it falls, it becomes difficult to detect the sensing object contained in the sample liquid. Based on this, each reaction film in the crystal unit 300 is selected.

  FIG. 28 shows a schematic configuration of the sensing device 1 using the composite crystal resonator 7 described above. In FIG. 28, the crystal resonators 3 and 300 are shown apart from each other for convenience, but these crystal resonators are constituted by one crystal piece as described above. The crystal resonator 300 is switched to one of the first oscillation circuit 401, the second oscillation circuit 402, and the third oscillation circuit 403 by switches 82 and 83. Thereby, the crystal unit 300 is configured to oscillate in a time division manner according to the vibration modes of S0, A0, and S1, as described above. The connection of the crystal resonator 3 is switched so that it is connected to either the fourth oscillation circuit 404 or the fifth oscillation circuit 405 by the switches 84 and 85. As a result, it is configured to oscillate in a time-sharing manner according to the S0 and A0 vibration modes as described above. The fourth oscillation circuit 404 and the fifth oscillation circuit 405 correspond to the first oscillation circuit 401 and the second oscillation circuit 402 in the first embodiment.

  The wiring between the crystal unit 300 and the oscillation circuits 401 to 403 shown in FIG. 28 will be described. Three electrodes 322, 324, and 326 on the lower side of the crystal piece 31 and the upper center of the crystal piece 31 in the figure. The electrode 323 and the upper left electrode 321 of the crystal piece 31 in the figure are connected to each other, and these connected electrodes are connected to one of the input side and the output side of the oscillation circuits 401 to 403 by the switch 83. . The electrode 325 is connected to the other of the input side and the output side of the oscillation circuits 401 to 403 by the switch 82. This wiring is the same as the connection for frequency adjustment of 3 pole MCF. Further, in the configuration in which the electrode 325 is connected to another electrode instead of the electrode 321 before each switch 82 and 83, and the electrode 321 is connected to each oscillation circuit via the switch 82 instead of the electrode 325. Good. The crystal resonator 3 is disconnected and connected to one of the oscillation circuits 404 and 405 via the switches 84 and 85, as in FIG. 12 described as the second embodiment. The switches 84 and 85 correspond to the switches 71 and 72 of the second embodiment.

  As described above, in this embodiment, the temperatures of the crystal resonators 3 and 300 are estimated based on the A0 mode oscillation of the crystal resonator 3 output from the fifth oscillation circuit 405. And based on the temperature, the control voltage of the oscillation circuits 401-404 is controlled, and the change by the temperature of the frequency output from each oscillation circuit is compensated. Outputs of the oscillation circuits 401 to 404 are transmitted to a frequency measurement unit (not shown) connected to the respective oscillation circuits 401 to 404, and the frequency measured by each frequency measurement unit is taken into the data processing unit 6. Details of the configuration for estimating the temperature and the configuration for controlling the control voltage of the oscillation circuit have been described in the above-described embodiment, and thus detailed description thereof is omitted here, but in the first embodiment. As described above, each oscillation circuit is connected to an individual adder 45, temperature compensation voltage calculator 44, and reference voltage control terminal 51, and a control voltage is supplied based on the temperature estimated by the temperature estimator 43. Shall be. The adding unit 45 and the temperature compensation voltage calculation unit 44 connected to the oscillation circuits 401 to 403 constitute a temperature compensation unit for the third oscillation circuit.

  Then, the data processing unit 6 individually stores the oscillation frequencies from the oscillation circuits 401 to 404 in the frequency storage unit 63 and displays the graphs on the display unit 64 as described in the first embodiment. The user can read the oscillation frequencies of the oscillation circuits 401 to 404 from the displayed graph, and detect each substance that reacts with the reaction films 311 to 314 in the sample solution.

The sixth embodiment has the same effect as each of the embodiments described above, and can detect a plurality of sensing objects with one crystal resonator 300, thereby reducing the operation cost of the apparatus. it can. By the way, in the sixth embodiment and other embodiments, the sensing object may be sensed by the user based on the display of the display unit 64 as described above, or at the frequency stored in the storage unit. The program 65 may be automatically executed based on the series data, and the display unit 64 may display whether or not the sensing object is adsorbed on the reaction film.
As in the sixth embodiment, when a sensing object is determined by combining changes in the frequency of three vibration modes or more vibration modes, the A0 mode is used as a temperature compensation frequency. You don't have to.
Further, as a method of using the oscillation frequency of the A0 mode to cancel out the temperature variation included in the oscillation frequency of the S0 mode or the S1 mode, the same concept as described at the end of the first embodiment is used. The difference frequency between the oscillation frequency of the mode and the oscillation frequency of the A0 mode, and the difference frequency between the oscillation frequency of the S1 mode and the oscillation frequency of the A0 mode may be obtained. When the sensing object is adsorbed on the adsorption film, the oscillation frequency in the S0 mode or the S1 mode is lowered, but the oscillation frequency in the A0 mode is not lowered. Therefore, the difference frequency changes when the sensing object is adsorbed on the adsorption film, and the amount of adsorption of the sensing object can be obtained based on the change.

  In the crystal resonator 300 according to the sixth embodiment, instead of the grounded electrodes 321, 322, and 325, one grounded electrode 327 is opposed to the electrodes 322, 323, and 326 as shown in FIG. May be provided. Reactive films 311, 312, and 313 are provided on the electrode 327. The reaction film 311 is provided at a position facing the electrode 324, the reaction film 312 is provided at a position facing between the electrodes 322 and 324 and between the electrodes 324 and 326, and the reaction film 313 is disposed at the electrodes 322 and 325, respectively. It is provided at an opposing position. If they are electrically separated from each other, the divided electrodes 321, 323, and 325 are arranged on the upper side of the crystal piece 31, and the electrode 327 is provided on the lower side so as to face these upper electrodes. The electrode 327 may be grounded. Further, in the crystal resonator 3, as described in the third embodiment, the upper or lower electrode of the crystal piece 31 may be configured as one electrode that is not divided from each other. In addition, in order to vibrate the crystal resonators 3 and 300 in the composite crystal resonator 8 in each vibration mode in this way, in addition to the wiring as shown in FIGS. Wiring can be used.

(Seventh embodiment)
In the seventh embodiment, similar to the sixth embodiment, a plurality of sensing objects are detected using the composite crystal resonator 8 in which a plurality of crystal resonators are formed on one crystal piece 31. . FIG. 30 is a top view of the composite crystal resonator 8 in which two crystal resonators 3 are arranged in the X-axis direction. For convenience of explanation, one crystal resonator 3 is 331 and the other crystal resonator 3 is 332. Reaction films 311 and 312 are provided on the crystal resonator 331, and a reaction film 313 is provided on the crystal resonator 332. FIG. 31 is a schematic view of the sensing device 1 to which the composite crystal resonator 8 is applied, and shows side surfaces of the crystal resonators 331 and 332. As shown in FIG. 31, in the crystal resonator 331, the reaction film 311 is provided between the electrodes 301 and 303 as in the first embodiment, and the reaction film 312 is provided on the electrodes 301 and 303. In the crystal resonator 332, the reaction film 313 is provided between the electrodes 301 and 303 similarly to the reaction film 311.

  In the sensing device 1 of the seventh embodiment, a first oscillation circuit 401 and a second oscillation circuit 402 (referred to as 421 and 422 in the drawing for convenience) corresponding to the crystal resonator 331 are provided. As in the second embodiment, the connection of the crystal resonator 331 is switched between the first oscillation circuit 421 and the second oscillation circuit 422 by the switches 71 and 72. In addition, a first oscillation circuit 401 and a second oscillation circuit 402 (referred to as 423 and 424 in the drawing for convenience) corresponding to the crystal resonator 332 are provided. As in the second embodiment, the connection of the crystal resonator 332 is switched between the first oscillation circuit 423 and the second oscillation circuit 424 by the switches 71 and 72. As a result, the crystal resonators 331 and 332 oscillate in the S0 mode and the A0 mode, respectively, as described in the above embodiments. Except for such differences, the sensing device 1 of the seventh embodiment is configured in the same manner as the sensing device 1 of the sixth embodiment.

  Based on the oscillation frequency of the quartz oscillator 332 in the A0 mode, the temperatures of the quartz oscillators 331 and 332 are detected. Based on the detected temperature, the oscillation output of the quartz oscillator 332 in the S0 mode, each A0 mode of the quartz oscillator 331, The oscillation output in the S0 mode is controlled. When the sensing object is adsorbed on the reaction film 311, the oscillation frequency of the quartz resonator 331 in the S0 mode is lowered without changing the oscillation frequency of the quartz resonator 331 in the A0 mode as described above. When the sensing object is adsorbed on the reaction film 313, the oscillation frequency in the S0 mode of the crystal unit 332 is lowered without changing the oscillation frequency in the A0 mode of the crystal unit 332 as described above.

  FIG. 32 shows the relationship between the positions of the reaction films 311 and 312 of the crystal resonator 331 and the vibration mode. The reaction film 312 is provided at a position close to the antinode of vibration in the A0 mode, and is provided at a position relatively distant from the antinode of vibration in the S0 mode. When the sensing object is adsorbed on the reaction film 312, the oscillation frequency of the quartz resonator 331 in the A0 mode is relatively greatly reduced, but the decrease in the oscillation frequency of the quartz resonator 331 in the S0 mode is only a small amount. Since the frequency of the S0 mode and A0 mode of the crystal resonator 331 and the frequency of the S0 mode of the crystal resonator 331 change as described above, each of the adsorbed by the reaction films 311, 312, and 313 in the sample solution It can be determined whether or not a sensing object is included.

  Further, as the configuration of the crystal resonators 331 and 332 and the wiring to the oscillation circuit, it is only necessary to take out the output of the S0 mode and the A0 mode. Therefore, in addition to the example shown in FIG. Can do. For example, as described in the third embodiment, one of the upper side and the lower side of the crystal piece 31 can be configured as one electrode 305. When the upper side is the electrode 305, in the crystal resonator 331, as shown in FIG. 33, reaction films 312 are provided at positions facing the electrodes 302 and 304, respectively.

  By the way, the crystal piece 31 of each of the above-described embodiments is not limited to the AT-cut one, and a crystal piece cut in another form can also be used. The above-mentioned 29 ° C. is an example of the reference temperature, and the value can be set individually according to the crystal resonator. For example, the control voltage connected to each crystal resonator 3, 300 can be controlled based on the amount of temperature deviation from the reference temperature set individually for the crystal resonators 3, 300.

  FIGS. 34 to 37 are shown in order to more clearly explain the relationship between the vibration in each mode of the crystal piece 31 and the position where the reaction films 311 and 312 are provided. 34 to 37 are perspective views schematically showing the crystal piece 31. The crystal piece 31 in FIG. 34 shows a stationary state that does not vibrate. The crystal piece 31 in FIG. 35 shows a state of vibrating in the S0 mode. 36 shows a state in which the crystal piece 31 is vibrating in the A0 mode, and the crystal piece 31 in FIG. 37 shows a state in which the crystal piece 31 is vibrated in the S1 mode. Since the crystal piece 31 vibrates in the thickness-shear vibration mode, it vibrates in the X-axis direction as illustrated.

  The arrows in the crystal piece 31 in FIGS. 35 to 37 indicate the displacement direction on the upper surface side of the crystal piece 31 with respect to the stationary state in FIG. 34. Regarding the displacement on the upper surface side, in the S0 mode, as described above, the vibration displacement at the central portion in the Z′-axis direction of the crystal piece 31 is larger than the vibration displacement at the peripheral portion in the Z′-axis direction. In the A0 mode, the direction of vibration displacement is reversed toward the Z′-axis direction as described above. In the S1 mode, as in the A0 mode, the vibration displacement at the central portion in the Z′-axis direction is larger than the vibration displacement at the peripheral portion in the Z′-axis direction, and the vibration displacement is reversed from the central portion toward the peripheral portion. Become a direction.

  FIGS. 38 and 39 are cross-sectional views of the crystal piece 31 during vibration in the S1 mode of FIG. FIG. 38 shows the AA arrow cross section and the CC arrow cross section of the both ends in the Z ′ direction of the crystal piece 31, and FIG. 39 shows the center portion of the crystal piece 31 in the Z ′ direction of the crystal piece 31. BB cross-section is shown. Each cross-sectional view is a cross-sectional view of the crystal piece 31 cut in the X direction as viewed from the Z ′ direction. As shown in these cross-sectional views, the crystal piece 31 is displaced in the opposite direction between the upper surface side and the lower surface side with the center in the thickness direction of the crystal piece 31 (node of vibration in the thickness direction) as a boundary. Although not shown, the same applies to each vibration in the A0 mode and the S0 mode. The crystal piece 31 vibrates by changing so that the displacement direction about the X axis of the crystal piece 31 is repeatedly reversed on the upper surface side and the lower surface side. A point P in FIG. 36 is a vibration displacement node that does not displace when vibrating in the A0 mode on the upper surface of the crystal piece 31, and the reaction film 311 shown in FIG. A point Q in FIG. 37 is a vibration displacement node that does not displace when vibrating in the S1 mode on the upper surface of the crystal piece 31, and the reaction film 312 shown in FIG. It is provided so that it can be done.

DESCRIPTION OF SYMBOLS 1 Sensing apparatus 2 Sensor unit 27 Distribution space 3, 300 Crystal oscillator 31 Crystal piece 301-304, 321-326 Electrode 311 Reaction film | membrane 401, 402 Oscillation circuit 4 Oscillation control part 6 Data processing part

Claims (6)

A piezoelectric vibrator having a piezoelectric piece on which excitation electrodes are formed on the one surface side and the other surface side, and a sample fluid supplied to the one surface side;
A first oscillation circuit for outputting the first oscillation frequency by vibrating the piezoelectric vibrator in a first vibration mode so that a first vibration displacement distribution is formed in the piezoelectric vibrator;
The piezoelectric vibrator is vibrated in the second vibration mode so that a second vibration displacement distribution is formed in which a region vibrated in the first vibration mode on one surface side of the piezoelectric piece becomes a node of vibration displacement. A second oscillation circuit for outputting a second oscillation frequency,
A switching unit that switches and connects the excitation electrode to the first oscillation circuit or the second oscillation circuit in order to switch and extract the first oscillation frequency and the second oscillation frequency.
A first adsorption film provided in the node of the vibration displacement for adsorbing a first sensing object contained in the sample fluid and changing the first oscillation frequency;
Measuring means for measuring the oscillation frequency of the first oscillation circuit and the oscillation frequency of the second oscillation circuit, and processing measurement data to detect the first sensing object based on the measurement result; Prepared,
The sensing device according to claim 1, wherein the oscillation frequency of the second oscillation circuit is used to cancel out a temperature variation included in the oscillation frequency of the first oscillation circuit.   The sensing device according to claim 1, wherein the first vibration mode is a main vibration of the thickness shear vibration, and the second vibration mode is an inharmonic overtone.   The sensing device according to claim 1, wherein the first vibration mode and the second vibration mode are in-harmonic overtones of thickness shear vibration.   4. The sensing device according to claim 2, wherein the first adsorption film is provided at a position including a position where the vibration displacement in the first vibration mode is maximized. In the piezoelectric piece, a piezoelectric vibrator that is vibrated in a third vibration mode is formed outside a region that is vibrated in the first vibration mode and the second vibration mode,
A third oscillation circuit for outputting the third oscillation frequency by vibrating the piezoelectric vibrator in the third vibration mode;
A second adsorption film for adsorbing a second sensing object contained in the sample fluid and changing the third oscillation frequency,
The measurement means further includes means for measuring an oscillation frequency of a third oscillation circuit and processing measurement data to detect the second sensing object based on the measurement result. The second oscillation circuit 5. The sensing according to claim 1, wherein the oscillation frequency is used for canceling out a temperature fluctuation included in the oscillation frequency of the second oscillation circuit. 6. apparatus.   6. The sensing device according to claim 1, wherein the piezoelectric piece is an AT-cut crystal piece.

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