JP4734657B2 - Transducer and measuring device provided with the transducer - Google Patents

Description

【Technical field】
[0001]
The present invention relates to a transducer used for measuring a physical property value such as an elastic constant in a minute sample, and a measuring apparatus including the transducer.
[Background]
[0002]
Conventionally, physical properties such as elastic constants and piezoelectric constants have been measured in advance for various materials such as sintered bodies such as metals, alloys and ceramics, or synthetic resin materials. It can be selected according to.
[0003]
However, when conducting various material research or physical property research in laboratories, etc., new materials with unknown physical property values have been generated or discovered, and measurement of physical property values is necessary to know the properties of this new material. Is required.
[0004]
When measuring an elastic constant or piezoelectric constant, which is one of such physical property values, a measuring device using a resonance method using a transducer is used.
[0005]
In other words, the transducer has a piezoelectric body that abuts against the sample to be measured, and this piezoelectric body inputs the required vibration to the sample and also detects the resonance caused by the vibration input to the sample with another transducer. In addition, an identification system has been proposed in which a desired physical property value is measured by analysis by an analysis means, and from the obtained physical property value to the specification of the type of sample can also be performed (for example, a patent) Reference 1).
[0006]
Here, a ceramic piezoelectric body is generally used as the piezoelectric body.
[Patent Document 1]
JP 2001-523332 A
DISCLOSURE OF THE INVENTION
[Problems to be solved by the invention]
[0007]
However, in conventional measurement devices, the use of a ceramic piezoelectric body as the piezoelectric body of the transducer limits the size of the sample capable of measuring physical properties, making it impossible to measure with a relatively small sample There was a problem of being.
[0008]
In other words, the resonance frequency in the measurement using the resonance method is inversely proportional to the size of the sample to be measured. Further, in the case of a ceramic piezoelectric body, the performance is degraded when the thickness is made smaller than a predetermined thickness. Since it occurs, the thickness cannot be made smaller than the predetermined thickness dimension, and the maximum frequency that can be output by the ceramic piezoelectric body is about 20 MHz from this thickness dimension condition. Therefore, the measurable sample is at least about 1 mm in size. There was a problem that was necessary.
[0009]
The present inventor has been studying ultra-high pressure phase minerals in the earth, and it is necessary to measure the physical properties of single crystals made of this ultra-high pressure phase mineral. Since only a sample having a size of about μm can be prepared, the conventional measuring device cannot accurately measure the physical property values.
[0010]
Therefore, the present inventor conducted research and development to make it possible to measure physical property values even with a sample having a size smaller than 1 mm, such as a single crystal of an ultra-high pressure phase mineral to be studied, and completed the present invention. It is a thing.
[Means for Solving the Problems]
[0011]
In the transducer of the present invention, A thin film electrode and the electrode was mounted on one end and electrically connected to the electrode A cylindrical casing; Ke Attach to the side of the electrode facing the inside of the casing Water Crystal, barium titanate, lead titanate, lead zirconate titanate, lead lanthanum zirconate titanate, lithium niobate, lead metaniobate, Rochelle salt, ethylenediamine tartrate, potassium tartrate, ammonium diphosphate, tungsten bronze -Based crystals, lithium tantalate, polyvinylidene fluoride, zinc oxide A thin film-like piezoelectric body, a conductive wire inserted into a casing and having its tip abutted against the side surface of the piezoelectric material, and an insulating material cured after filling the casing in which the conductive wire is inserted in a liquid state A transducer having a casing as a conductor and a coaxial cable connected to a piezoelectric body together with a conductor inserted into the casing. .
[0012]
further, The piezoelectric body has a thickness dimension of 0.02 mm or less, Conductor Is , A metal or alloy linear body having a Q value of 100 or less, 0.5 mm or less , electrode Is , Made of metal or alloy with Q value over 500 A thin film of The film thickness should be 0.01mm or less The casing has a diameter of 1.0mm or less .
[0013]
In the measuring device including the transducer of the present invention, Two transducers, a transmitter connected to one transducer, a lock-in amplifier connected to the other transducer and connected to the transmitter, and a control unit connected to the transmitter and the lock-in amplifier. Measure the resonance frequency of the object measured by the transducer It was.
[0014]
According to invention of Claim 1, Connected to the piezoelectric body as a coaxial cable with the conductor inserted in the casing as a conductor As a result, the influence of resonance by the casing can be suppressed, and excitation or detection of vibration with high accuracy can be achieved.
[0015]
Moreover, in the transducer according to claim 1, the piezoelectric body is made of quartz, barium titanate, lead titanate, lead zirconate titanate, lead lanthanum zirconate titanate, lithium niobate, lead metaniobate, Rochelle salt, ethylene tartrate. By using one of diamine, potassium tartrate, dibasic ammonium phosphate, tungsten bronze crystals, lithium tantalate, polyvinylidene fluoride, and zinc oxide, the piezoelectric body can be made thinner, so sample measurement with the piezoelectric body itself It can suppress the occurrence of resonance in the frequency band. Ru .
[0016]
According to invention of Claim 2, in the transducer of Claim 1, The piezoelectric body can excite or detect vibrations at higher frequencies with accuracy by making the thickness dimension 0.02 mm or less, Conductor Is A linear body made of metal or alloy having a Q value of 100 or less Because , Diameter dimensions 0.5 mm or less The electrode is a metal or alloy thin film having a Q value of 500 or more, the film thickness is 0.01 mm or less, and the casing is 1.0 mm or less in diameter. It is possible to suppress the occurrence of resonance in the conducting wire and to inhibit the conducting wire from inhibiting the vibration of the piezoelectric body, thereby enabling more accurate excitation or detection of the vibration.
[0017]
According to invention of Claim 3, Two transducers according to claim 1 or claim 2, a transmitter connected to one transducer, a lock-in amplifier connected to the other transducer and connected to the transmitter, and connected to the transmitter and the lock-in amplifier And a control device that measures the resonance frequency of the object to be measured sandwiched between two transducers, so that the transducer can accurately excite or detect vibration while suppressing the influence of resonance other than the sample. Providing measurement equipment that can measure physical properties such as elastic constants and piezoelectric constants of specimens of 1 mm or less it can.
[Brief description of the drawings]
[0019]
FIG. 1 is a schematic configuration diagram of a measuring apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a transducer according to an embodiment of the present invention.
[FIG. 3] It is explanatory drawing of the semi-rigid coaxial cable used for measurement of the load added to the to-be-measured body.
Explanation of symbols
[0020]
S DUT
11 Oscillator
12 Excitation side transducer
13 Detection transducer
14 Lock-in amplifier
15 Control unit
21 Piezoelectric material
22 conductor
23 electrodes
24 casing
25 Insulation material
BEST MODE FOR CARRYING OUT THE INVENTION
[0021]
In the transducer according to the present invention and the measuring device including the transducer, the transducer is formed in a cylindrical casing having a thin film electrode attached to one end thereof, and a thin film attached to the side of the electrode facing the inside of the casing. The piezoelectric body, a conductive wire coaxially inserted into the casing and connected to the piezoelectric body, and an insulating material filled in the casing.
[0022]
In this way, by arranging the casing and the conductor coaxially and connecting the conductor to the piezoelectric body provided at one end portion of the casing, the influence of resonance by the casing can be suppressed, and accurate vibration can be prevented. Excitation or detection may be possible.
[0023]
Furthermore, the piezoelectric material is quartz (SiO ₂ ), Barium titanate (BaTiO), lead titanate (PbTiO) _Three ), Lead zirconate titanate (Pb (Zr, Ti) O) _Three ), Lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O) _Three ), Lithium niobate (LiNbO _Three ), Lead metaniobate (PbNb ₂ O ₆ ), Rochelle salt (NaKC _Four H _Four O ₆ ・ 4H ₂ O), ethylenediamine tartrate (C ₆ H ₁₄ N ₂ O ₆ ), Potassium tartrate (2 (K ₂ C _Four H _Four O ₆ ) ・ H ₂ O), dibasic ammonium phosphate (NH _Four H ₂ PO _Four ), Tungsten bronze crystals (Na _x WO _Three ), Lithium tantalate (LiTaO) _Three ), Polyvinylidene fluoride (PVDF), or zinc oxide (ZnO) can be used to reduce the thickness of the piezoelectric body, thereby suppressing the occurrence of resonance in the sample measurement frequency band due to the piezoelectric body itself. By making the thickness dimension of 0.1 mm or less, high-frequency vibrations can be excited or detected, and physical properties such as elastic constants and piezoelectric constants of samples of 1 mm or less can be measured.
[0024]
The piezoelectric body is not limited to the above-described material, and may be any single crystal, polycrystalline, or amorphous piezoelectric body that can be used as a substitute for the above material.
[0025]
In addition, when the conducting wire is made of a metal or alloy linear body having a Q value of 100 or less, it is possible to suppress resonance in the conducting wire, and when the diameter of the conducting wire is 1.0 mm or less. Can reduce the contact surface of the lead wire connected to the piezoelectric body with the piezoelectric body, thereby suppressing the lead wire from inhibiting the vibration of the piezoelectric body, and improving the accuracy of excitation of vibration by the transducer or the accuracy of detection of vibration. Further improvement can be achieved.
[0026]
Also, when the electrode is made of a metal or alloy thin film having a Q value of 500 or more and the film thickness dimension is 0.01 mm or less, the vibration generated by the piezoelectric body or the vibration transmitted to the piezoelectric body is attenuated by the electrode. Therefore, the performance of the transducer can be improved.
[0027]
Here, the Q value is an index indicating the degree of energy absorption of the elastic wave by the medium in the propagation of the elastic wave, and if the Q value is large, the energy absorption of the elastic wave is small and the elastic wave is propagated with a small loss. If the Q value is small, the energy absorption of the elastic wave is large, and the elastic wave can be greatly attenuated by propagation over a relatively short distance.
[0028]
In the following, embodiments of the present invention will be described in more detail based on the drawings. FIG. 1 is a schematic configuration diagram of a measuring apparatus according to the present embodiment.
[0029]
The measurement apparatus of the present embodiment includes an oscillator 11 that outputs an electrical signal having a required frequency, an excitation-side transducer 12 to which the electrical signal output from the oscillator 11 is input, and the excitation-side transducer 12 that is opposed to the excitation-side transducer 12. A detection-side transducer 13 that detects the vibration that is disposed and passes through the measurement object S, and a lock-in amplifier 14 that receives the electrical signal output from the detection-side transducer 13 and the electrical signal output from the oscillator 11; The control unit 15 analyzes the signal amplified in the lock-in amplifier 14.
[0030]
In the present embodiment, the control unit 15 also performs output control of the oscillator 11, and enables automatic detection of the resonance frequency by performing measurement while sequentially changing the frequency of the electrical signal output from the oscillator 11.
[0031]
The lock-in amplifier 14 is used to increase the detection accuracy of the vibration having the desired frequency, amplifies and outputs only the electric signal of the vibration having the desired frequency, and outputs the output signal to the control unit. Analyzed by 15.
[0032]
The control unit 15 is constituted by a personal computer in the present embodiment, the measurement program is stored in the hard disk of the personal computer, and the oscillator 11 is controlled based on the measurement program by starting the measurement program. At the same time, the output signal of the lock-in amplifier 14 is analyzed to calculate physical properties such as elastic constants and piezoelectric constants.
[0033]
The excitation side transducer 12 and the detection side transducer 13 are configured as follows. That is, as shown in FIG. 2, each transducer 12, 13 is mounted on a cylindrical casing 24 having a thin film electrode 23 mounted on one end thereof, and on a side surface of the electrode 23 facing the inside of the casing 24. The thin film piezoelectric body 21, the conductor 22 inserted coaxially into the casing 24 and connected to the piezoelectric body 21, and the insulating material 25 filled in the casing 24 are configured.
[0034]
In particular, the electrode 23 is attached to one end portion of the casing 24 to close an opening provided at the end portion of the casing 24, and the casing 24 has a bottomed cylindrical shape with the electrode 23.
[0035]
In this embodiment, the piezoelectric body 21 is a thin film lithium niobate (LiNbO) having a thickness dimension of 0.1 mm or less. _Three ). In the following, this thin film lithium niobate is simply referred to as “LiNbO”. _Three ". This LiNbO _Three Is a plate-like LiNbO with a predetermined thickness _Three Is polished to a thickness dimension of 0.1 mm or less, preferably 0.05 mm or less, and particularly 0.02 mm in this embodiment. LiNbO like this _Three By making the thickness as thin as possible, the occurrence of resonance of the piezoelectric body 21 itself can be suppressed, and excitation or detection of vibration with high accuracy can be made possible.
[0036]
In this embodiment, LiNbO _Three Is single crystal LiNbO _Three Y-10 ° cut plate-like crystal is polished to a predetermined thickness. By using a Y-10 ° cut crystal, high-frequency longitudinal and transverse vibrations can be simultaneously generated. Since it can be excited or detected, a high-performance transducer can be obtained. LiNbO _Three Is not limited to the case of forming by polishing, and may be formed by vapor deposition, for example.
[0037]
Moreover, as the piezoelectric body 21, LiNbO _Three As well as quartz (SiO ₂ ), Barium titanate (BaTiO), lead titanate (PbTiO) _Three ), Lead zirconate titanate (Pb (Zr, Ti) O) _Three ), Lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O) _Three ), Lead metaniobate (PbNb) ₂ O ₆ ), Rochelle salt (NaKC _Four H _Four O ₆ ・ 4H ₂ O), ethylenediamine tartrate (C ₆ H ₁₄ N ₂ O ₆ ), Potassium tartrate (2 (K ₂ C _Four H _Four O ₆ ) ・ H ₂ O), dibasic ammonium phosphate (NH _Four H ₂ PO _Four ), Tungsten bronze crystals (Na _x WO _Three ), Lithium tantalate (LiTaO) _Three ), Polyvinylidene fluoride (PVDF), or zinc oxide (ZnO) may be used as a thin film having a thickness of 0.1 mm or less, and piezoelectric materials other than these may be used.
[0038]
It is desirable to use a wire rod that is less likely to cause resonance, such as a metal or alloy having a Q value of 100 or less, and the conductor wire 22 is a wire rod having a diameter dimension of 1.0 mm or less, and the diameter dimension may be as small as possible. desirable. In this way, by using the lead wire 22 having a small Q value and a small diameter, it is possible to suppress the occurrence of resonance based on the natural vibration of the lead wire 22 itself, and the piezoelectric member 21 of the lead wire 22 connected to the piezoelectric member 21. It is possible to prevent the piezoelectric element 21 from being obstructed by the conductive wire 22 by reducing the contact area with the conductor 22.
[0039]
The lead wire 22 is connected to the piezoelectric body 21 by connecting the tip of the lead wire 22 to the LiNbO that is the piezoelectric body 21 _Three The insulating material 25 is injected into the inside of the casing 24 having a bottomed cylindrical shape, and the insulating material 25 is cured to connect the conductive wire 22 to the piezoelectric body 21. This is done by maintaining the state.
[0040]
In the present embodiment, a lead wire having a diameter of 0.5 mm is used for the conductive wire 22, and it is desirable to further reduce the diameter if possible.
[0041]
The electrode 23 is composed of a metal or alloy thin film having a Q value of 500 or more. In particular, the electrode 23 has little sound attenuation in a high frequency region of about 100 MHz, and resonance based on the natural vibration of the electrode 23 itself. It is desirable to use a material in which the occurrence of the above is suppressed. Further, the electrode 23 is a thin film having a film thickness dimension of 0.01 mm or less, and the occurrence of resonance in the electrode 23 is suppressed by making the film thickness dimension as small as possible.
[0042]
The electrode 23 and the piezoelectric body 21 are joined by crimping the piezoelectric body 21 to the electrode 23. After the piezoelectric body 21 is crimped to the electrode 23, the electrode 23 is attached to one end portion of the casing 24. ing.
[0043]
The electrode 23 is also attached to the casing 24 by pressure bonding. After the pressure bonding to the casing 24, by injecting a liquid state insulating material 25 into the bottomed cylindrical casing 24, the insulating material 25 The electrode 23 is held at the end of the casing 24. When the electrode 23 is mounted on the casing 24, the piezoelectric body 21 that is pressure-bonded to the electrode 23 is mounted so as to be positioned inside the casing 24.
[0044]
Note that after the piezoelectric body 21 is pressure-bonded to the electrode 23, the piezoelectric body 21 or the electrode 23 may be polished to further reduce the thickness of the piezoelectric body 21 or further reduce the thickness of the electrode 23. In particular, the piezoelectric body 21 is attached to the electrode 23 and polished to facilitate the polishing operation. Alternatively, the piezoelectric body 21 may be formed by directly depositing necessary atoms or molecules on the electrode 23.
[0045]
In this embodiment, the electrode 23 uses a titanium foil having a thickness of 0.005 mm, and it is desirable to further reduce the film thickness if possible.
[0046]
The electrode 23 is not limited to the titanium foil, but may be a thin film made of aluminum, duralumin, tungsten carbide or the like, but in this embodiment, the titanium foil is selected from the viewpoint of durability and availability. ing.
[0047]
The casing 24 is preferably made of a material having a relatively large sound wave attenuation to suppress the occurrence of resonance. In this embodiment, the casing 24 is made of stainless steel. In particular, if the casing 24 is made of stainless steel, it can be electrically connected to the electrode 23 attached to one end of the casing 24, and the casing 24 itself can be used as a conducting wire connected to the electrode 23.
[0048]
In the cylindrical casing 24, the size of the sample, which is the measurement object S, is smaller than 1 mm. Therefore, the measurement object S can be securely connected by the excitation side transducer 12 and the detection side transducer 13 by making the diameter dimension as small as possible. Since it can be clamped, in this embodiment, the diameter of the casing 24 is φ1.0 mm.
[0049]
In particular, the casing 24 can reduce the area of the electrode 23 mounted on the tip by making the diameter dimension as small as possible, so that coherent vibration can be input to the measurement object S, and the measurement accuracy can be improved. Can be improved.
[0050]
As the insulating material 25 filled in the casing 24, it is desirable to suppress the occurrence of resonance by using a material having a relatively large sound wave attenuation. In this embodiment, epoxy is used. The insulating material 25 is not limited to epoxy, and may be any insulating material that has a relatively large sound attenuation.
[0051]
By configuring the transducers 12 and 13 in the form of coaxial cables in this way, in the propagation of high-frequency electrical signals in the conducting wire 22, the attenuation of the electrical signal is suppressed, and the electrode 23, the casing 24, and the conducting wire 22 that are external noises. It is possible to easily suppress the influence of resonance vibration.
[0052]
In particular, in each of the transducers 12 and 13, the S / N ratio can be improved by providing an impedance converter in the vicinity of the piezoelectric body 21, and the measurement capability can be improved.
[0053]
Each of the transducers 12 and 13 configured as described above is connected to the oscillator 11 and the lock-in amplifier 14 via connectors (not shown).
[0054]
In addition, as shown in FIG. 1, in this embodiment, the excitation side transducer 12 is arranged below the measurement object S, and the measurement object S is supported by the excitation side transducer 12, and the detection side transducer 13 is It arrange | positions to the to-be-measured body S above.
[0055]
Further, the detection-side transducer 13 is mounted on an XYZ stage (not shown) so as to be movable in any of the X-axis direction, the Y-axis direction, and the Z-axis direction, and the detection-side transducer 13 is lowered to the excitation-side transducer 12 side to be measured. S can be held between the detection-side transducer 13 and the excitation-side transducer 12.
[0056]
A measurement method using the measurement apparatus configured as described above will be briefly described. First, in the measurement device, the detection side transducer 13 is raised by the XYZ stage, and the excitation side transducer 12 and the detection side transducer 13 are separated from each other by a predetermined interval, and the control unit 15 controls the oscillator 11 to obtain a required frequency. The electrical signals are sequentially output to detect the background. The detected background information is stored in the control unit 15.
[0057]
Next, in the measuring apparatus, the measurement object S is placed on the electrode 23 on the excitation side transducer 12 arranged with the electrode 23 facing upward, and the detection side transducer 13 is lowered on the XYZ stage to detect the excitation side transducer 12. The measurement object S is sandwiched and fixed by the side transducer 13.
[0058]
At this time, a semi-rigid coaxial cable 30 is particularly connected to the detection-side transducer 13 as shown in FIG. 3, and the excitation-side transducer 12 and the detection-side transducer 13 are measured from the measurement of the distortion amount in the semi-rigid coaxial cable 30 as will be described later. Thus, it is possible to measure the load applied to the measured object S when the measured object S is sandwiched.
[0059]
It is known that the resonance frequency measured by the measuring device changes depending on the load applied to the measurement object S, and the measurement accuracy of the measuring device can be improved by measuring the load.
[0060]
After fixing the object to be measured S by the excitation side transducer 12 and the detection side transducer 13, the measuring device sequentially outputs an electrical signal having a required frequency from the oscillator 11 to measure the resonance frequency, and the obtained result is obtained. Based on this, the required physical property values are calculated.
[0061]
In the measurement apparatus of this embodiment, the detection accuracy of the resonance frequency is improved by providing the lock-in amplifier 14, and the performance of each transducer 12, 13 is improved, so that the measurement object S Even if the size is smaller than 0.2 mm, the physical property value can be measured.
[0062]
The measuring device configured in this way enables not only measurement of physical property values of single crystals and sintered bodies of ultrahigh-pressure phase minerals described above, but also measurement of physical property values of space samples such as meteorites and fine samples such as powder ceramics. can do.
[0063]
In addition, since the measuring device of the present embodiment measures the resonance frequency of the measured object S, it can also detect the presence or absence of internal defects in the known measured object S, and a bearing ball or solder of 1.0 mm or less It can also be used as a sphere inspection device.
[0064]
Alternatively, when the deviation of the resonance frequency is used in the measurement of the mass of the minute substance in the electronic balance, it is possible to provide a more compact mass measurement sensor for the minute sample by using the measurement apparatus of the present embodiment. Can do.
[0065]
Alternatively, when using a material whose resonance frequency is known to change with temperature and humidity, the temperature and humidity can be measured by measuring the resonance frequency of this material, and the measuring device can be made compact. Therefore, it is possible to provide a compact temperature sensor or humidity sensor.
[0066]
Alternatively, when the transducer of the present invention is used as an acoustic emission sensor, it can be an acoustic emission sensor capable of measuring higher frequencies. For example, in a rock destruction experiment for earthquake research in the earth science field, Detection is possible, and high-precision research can be made possible.
[0067]
Finally, a load measuring method for measuring the load applied to the measurement object S by the excitation side transducer 12 and the detection side transducer 13 from the measurement of the strain amount in the semi-rigid coaxial cable 30 described above will be described.
[0068]
As shown in FIG. 3, the detection-side transducer 13 is connected to the semi-rigid coaxial cable 30 via a connector 35 for connecting to the semi-rigid coaxial cable 30.
[0069]
The semi-rigid coaxial cable 30 is provided with a horizontal region 36 in which a distal end side to which a connector 35 is connected is directed vertically downward and is curved approximately 90 ° at a predetermined midway portion to be in a substantially horizontal state. The detection-side transducer 13 is attached to the tip of the semi-rigid coaxial cable 30 via the connector 35 in a suspended state. In FIG. 3, reference numeral 37 denotes an impedance converter in which the base end of the semi-rigid coaxial cable 30 is connected.
[0070]
In the horizontal region 36 of the semi-rigid coaxial cable 30, the first strain gauge 31 and the second strain gauge 32 are disposed in contact with the lower surface of the semi-rigid coaxial cable 30, and the first rigid gauge cable 30 is sandwiched between the first rigid gauge cable 30 and the first strain gauge 31. A third strain gauge 33 is placed in contact with the upper surface of the semi-rigid coaxial cable 30 so as to face the strain gauge 31, and a fourth strain gauge 34 is placed facing the second strain gauge 32 across the semi-rigid coaxial cable 30. The semi-rigid coaxial cable 30 is disposed in contact with the upper surface.
[0071]
The first strain gauge 31 and the second strain gauge 32 are provided at a predetermined interval along the longitudinal direction of the horizontal region 36 of the semi-rigid coaxial cable 30, and the third strain gauge 33 and the fourth strain gauge 34 are semi-rigid. A predetermined distance is provided along the longitudinal direction of the horizontal region 36 of the coaxial cable 30.
[0072]
The first to fourth strain gauges 31, 32, 33, and 34 are connected to each other by a Wheatstone bridge, and an output signal from the Wheatstone bridge connection is input to the control unit 15, and the control unit 15 performs load conversion. ing.
[0073]
When performing load calculation, the measuring device is a semi-rigid coaxial cable in which the detection-side transducer 13 is first attached to the tip and the first to fourth strain gauges 31, 32, 33, 34 are attached to the horizontal region 36. 30 is lowered to bring the detection-side transducer 13 into contact with the measurement object S.
[0074]
As the detection-side transducer 13 comes into contact with the measured object S, the measuring device stops the lowering of the semi-rigid coaxial cable 30 but detects that the detection-side transducer 13 comes into contact with the measured object S. As a result, the semi-rigid coaxial cable 30 descends by a predetermined amount and stops immediately after the detection-side transducer 13 comes into contact with the object S to be measured.
[0075]
A predetermined amount of load acts on the measured object S due to the descending of the semi-rigid coaxial cable 30 immediately after the detection-side transducer 13 contacts the measured object S. At this time, the semi-rigid coaxial cable 30 is connected to the measured object S. The detection-side transducer 13 cannot be lowered by the excitation-side transducer 12 that supports S and the measured object S, and the tip side in the horizontal region 36 of the semi-rigid coaxial cable 30 is warped up.
[0076]
As the semi-rigid coaxial cable 30 in the horizontal region 36 warps, tensile stress acts on the first strain gauge 31 and the second strain gauge 32, and compression occurs on the third strain gauge 33 and the fourth strain gauge 34. Stress acts to generate an electromotive force corresponding to the tensile stress and the compressive stress, and an output signal is obtained. The control unit 15 analyzes the output signal and performs load conversion to measure the load. The control unit 15 stores in advance a conversion formula between the power value of the output signal and the load applied to the measurement object S, and the control unit 15 calculates the load based on the conversion formula.
[0077]
By providing a means for measuring the load acting on the measurement object S in this way, it is possible to perform measurement taking into account the load applied to the measurement object S, as well as the excitation-side transducer 12 and the detection side. It can also be detected that the measured object S can be accurately held by the transducer 13.
[Industrial applicability]
[0078]
It is possible to provide a measuring apparatus capable of measuring a physical property value even with a sample having a size smaller than 1 mm. Also, since vibrations of minute objects can be accurately detected, a defect detection device for bearing balls and solder balls of 1.0 mm or less, a device for measuring the mass of minute objects using resonance frequency deviation, and a resonance frequency deviation A measuring device or an acoustic emission sensor can be configured for the temperature and humidity used.

Claims (3)

A thin film electrode;
The electrode is mounted on one end, and a cylindrical casing electrically connected to the electrode ;
Water crystal was mounted on a side surface of the electrode facing the inside of the casing, barium titanate, lead titanate, lead zirconate titanate, lead lanthanum zirconate titanate, lithium niobate, lead metaniobate, Rochelle salt, A thin-film piezoelectric body comprising any one of ethylenediamine tartrate, potassium tartrate, dibasic ammonium phosphate, tungsten bronze crystal, lithium tantalate, polyvinylidene fluoride, and zinc oxide ;
A conducting wire inserted into the casing and having its tip abutted against the side surface of the piezoelectric body;
An insulating material hardened after filling in a liquid state in the casing into which the conducting wire is inserted;
A transducer comprising:
A transducer in which the casing is used as a conducting wire and connected to the piezoelectric body in the form of a coaxial cable together with the conducting wire . The piezoelectric body has a thickness dimension of 0.02 mm or less,
The conducting wire is a metal or alloy linear body having a Q value of 100 or less, and has a diameter of 0.5 mm or less ,
The electrode is a metal or alloy thin film having a Q value of 500 or more, and the film thickness dimension is 0.01 mm or less.
The transducer according to claim 1 , wherein the casing has a diameter of 1.0 mm or less . Two transducers according to claim 1 or claim 2;
A transmitter connected to one of the transducers;
A lock-in amplifier connected to the other transducer and connected to the transmitter;
A control unit connected to the transmitter and the lock-in amplifier;
With
A measuring apparatus comprising a transducer for measuring a resonance frequency of a measurement object sandwiched between two transducers .

Images