JP2011005058A - Mechanical characteristic measuring device and method for using mechanical characteristic measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical characteristics measuring device with high measuring accuracy and low power consumption.SOLUTION: The mechanical characteristics measuring device 10 is characterized in that it comprises: an oscillation sensor 12 including a piezoelectric oscillator 12a to be brought into contact with an object to be measured; a constant voltage oscillating circuit 11 to supply the piezoelectric vibrator 12a with electric energy; an oscillating current measuring part 13 to measure the oscillating current generated in the piezoelectric oscillator 12a; a first switching means 14 switching ON/OFF; and a second switching means 14 switching ON/OFF, and the constant voltage oscillating circuit 11 is electrically connected with the oscillation sensor 12 through the first switching means 14 and the oscillation sensor 12 is electrically connected with the oscillating current measuring part 13 through the second switching means 14.

Description

  The present invention relates to a mechanical property measuring device and a method for using the mechanical property measuring device.

  With the advancement of IT and network technology supported by digitalization, the information handled is increasing, and the information accumulated along with this has been increasing. Information obtained by input devices using sensors, etc., is analyzed and judged accurately, and processed into easy-to-understand information, and notifying people is important for realizing social safety, security, comfort, and environmental conservation. It is. An example of an input device that acquires information is an input device that uses a piezoelectric vibrator as a sensor. As an input device using a piezoelectric vibrator, for example, an oscillating degree measuring device for determining a fixed state of an object (for example, see Patent Document 1), an ultrasonic transducer system for use in ultrasonic diagnosis (for example, see Patent Document 2). Etc.

  Along with the maturity of society, aging has progressed and various problems have arisen. People want health and anti-aging. In such a situation, for example, there is a demand for a health sensor that can measure and indicate a skin condition that is significantly affected by changes in the health condition and aging, regardless of location, at a low cost, simply and accurately. Yes. Today, electronic devices have become smaller and lighter due to the miniaturization of electronic components, and portable electronic devices such as mobile phones using wireless communication or notebook personal computers have become widespread. There is a great expectation that such a portable electronic device will be equipped with the above-described health sensor to accumulate acquired information and receive services based on the information. In order to realize this, the above-mentioned health sensor needs to overcome the technical problem of, for example, high measurement accuracy so that accurate information can be acquired, small size, and low power consumption that can be driven by a battery. There is.

  In order to evaluate the mechanical characteristics of elastic bodies such as human skin, devices using piezoelectric vibrators have been proposed (see Patent Documents 3 to 5). As shown in FIG. 10A, an elastic characteristic measuring apparatus 1000 described in Patent Document 3 includes a constant voltage driving circuit 1001 for applying a constant voltage to a three-terminal piezoelectric vibrator 1002, and a harmonic component. Is provided with a filter amplifier circuit 1006 and a virtual ground current detection circuit 1003. In this device, the above-described constituent members are connected in a loop shape to constitute a feedback self-excited oscillation circuit. When the measurement object is brought into contact with the piezoelectric vibrator in the driving state of this apparatus, an equivalent electrical impedance of the measurement object is loaded. For this reason, as shown in FIG. 10B, the frequency and current value of the self-excited oscillation circuit are not in contact with the measurement object (solid waveform 1008) and in contact with the measurement object ( It changes with a dashed waveform 1009). As an apparatus using such a change, for example, a skin elasticity sensor described in Patent Document 4 can be cited. As shown in FIG. 11, the skin elasticity sensor 1100 includes a piezoelectric vibrator in which a rod-shaped piezoelectric ceramic cylinder 1102 to which a hemispherical contactor 1103 is attached is supported on an exterior housing 1107 by a spring 1104 for pressurization. And an electric circuit. The piezoelectric vibrator is driven by longitudinal vibration in the length direction. Moreover, as an application of the above-described elastic property measuring apparatus, for example, a skin age calculating apparatus described in Patent Document 5 can be cited. FIG. 12A shows a system block diagram of this apparatus, and FIG. 12B shows an external view. Similar to the device described in Patent Document 4, this device 1200 is a device that calculates skin age from a change in resonance frequency or natural period due to contact of a piezoelectric vibrator to which a hemispherical contact 1203 is attached. A display unit 1208 is provided on the surface of the device 1200. Of the exterior casing 1207 of the device 1200, the portion in the vicinity of the contact 1203 serves as a skin support so as to obtain a constant pressure against the piezoelectric vibrator. By obtaining a stable pressure, Measurement malfunction can be prevented.

Japanese Patent Laid-Open No. 3-148032 JP 2001-258879 A JP 2003-270219 A JP-A-2005-52212 JP 2001-212087 A

  In the devices described in Patent Documents 3 to 5, the change in the resonance frequency and the change in the current value are used for the measurement as described above. The change in the resonance frequency occurs when the piezoelectric vibrator is continuously driven and a measurement object such as skin is brought into contact as a mechanical load. The change in the current value occurs in response to a change in the electrical equivalent circuit of the piezoelectric vibrator due to a change in pressing pressure caused by the contact and vibration suppression.

However, these devices have three problems related to measurement accuracy. Specifically, there are the following problems.
The first problem is the relationship between the difference between the mechanical characteristics of the piezoelectric vibrator and the mechanical characteristics of the measurement object and the accuracy of the resonance frequency measurement caused by the self-excited oscillation circuit. If the difference is large, the change in the resonance frequency becomes large, so that the self-excited oscillation circuit cannot follow the change and may cause a malfunction. On the other hand, if the difference is small, the change in the resonance frequency is small, so that accurate measurement becomes difficult. Also, the measurable range of these devices is very narrow. For this reason, for example, in order to accurately measure each part of a person's cheek, chin, arm, foot, etc. with different thickness and density and different mechanical properties as a measurement object, a piezoelectric vibrator optimized for each part Must be prepared.
The second problem is a problem of a decrease in accuracy of repeated measurement of a measurement object in which a change occurs in the resonance frequency and the oscillating current due to a change in the pressing pressure during measurement. For example, when these devices are used for measuring human skin, the user presses the contact attached to the tip of the piezoelectric vibrator against the skin until the measurement is completed. At this time, it is necessary to maintain a constant pressing pressure. When the pressing pressure changes, a response due to the time constant of the feedback circuit occurs. This response causes a change in the resonance frequency or natural period and a change in the oscillating current amplitude, resulting in a large error in measurement.
The third problem is a problem of a decrease in measurement accuracy due to heat generation of the piezoelectric vibrator because it is necessary to continuously drive until the measurement is completed. Due to the heat generated by the energy loss of the piezoelectric vibrator, the mechanical characteristics of the piezoelectric vibrator change during the measurement. As a result, a change occurs in the resonance frequency, and accurate measurement becomes difficult.
In addition to the above three problems, these devices have a problem of power consumption because they need to be continuously driven until the measurement is completed. For example, when these devices are mounted on a portable electronic device such as a notebook computer or a cellular phone so that the portable device can be carried, the battery is consumed very much and it is difficult to carry the device.

  An object of the present invention is to provide a mechanical property measuring apparatus with high measurement accuracy and low power consumption.

In order to achieve the above object, the mechanical property measuring apparatus of the present invention comprises
A vibration sensor including a piezoelectric vibrator brought into contact with an object to be measured; a constant voltage oscillation circuit that supplies electric energy to the piezoelectric vibrator; a vibration current measuring unit that measures a vibration current generated in the piezoelectric vibrator; A first switching means that can be switched off and a second switching means that can be switched on / off;
The constant voltage oscillation circuit is electrically connected to the vibration sensor via the first switching means;
The vibration sensor is electrically connected to the vibration current measuring unit via the second switching means.

  According to the present invention, it is possible to provide a mechanical property measuring apparatus with high measurement accuracy and low power consumption.

It is a circuit block diagram which shows the structure of an example in Embodiment 1 of the mechanical characteristic measuring apparatus of this invention. It is a perspective view which shows the example of the vibration sensor in the said example. It is a figure explaining the usage method of the said example. It is a figure which shows the example of the waveform of the constant voltage applied to a piezoelectric vibrator in the example usage method. It is a figure which shows the example of accumulation | storage of the vibration energy in the usage method of the said example. (A) And (b) is a figure which shows the example of the oscillating current which attenuate | damps in the usage method of the said example. (C) is a figure which shows an example of the analysis in the usage method of the said example. It is a circuit block diagram which shows the structure of the other example in Embodiment 1 of the mechanical characteristic measuring apparatus of this invention. (B) is a perspective view which shows the example of the vibration sensor in the said other example. It is a figure explaining the usage method of the said other example. It is a circuit block diagram which shows the structure of an example in Embodiment 2 of the mechanical property measuring apparatus of this invention. (A) is a circuit block diagram which shows the structure of an example of the conventional elastic characteristic measuring apparatus. (B) is an oscillating current waveform measured by the apparatus. It is a schematic diagram which shows the structure of an example of the conventional skin elasticity sensor. (A) is a system block diagram which shows the structure of an example of the conventional skin age calculation apparatus. (B) It is an external view of the example.

  Hereinafter, the mechanical property measuring device and the method of using the mechanical property measuring device of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

(Embodiment 1)
FIG. 1 shows a configuration of an example of a mechanical property measuring apparatus according to the present embodiment. As shown in the figure, the mechanical characteristic measuring apparatus 10 includes a constant voltage oscillation circuit 11, a vibration sensor 12 to which a piezoelectric vibrator 12a is attached, an oscillating current measurement circuit 13, and a changeover switch 14. The oscillating current measurement circuit 13 includes an electric filter 16 and an analysis unit 17. The piezoelectric vibrator 12a is a two-terminal piezoelectric vibrator. The constant voltage oscillation circuit 11 is electrically connected to the vibration sensor 12 via the changeover switch 14. The vibration sensor 12 is electrically connected to the electric filter 16 via the changeover switch 14. The analysis unit 17 is provided with an electrical terminal for connection to a subsequent circuit or the like. The change-over switch 14 is a switch that can be switched (on / off switchable) between connection and disconnection between the above-described components. In the mechanical property measuring apparatus of this embodiment, the first switching means and the second switching means are changeover switches having the functions of both, but the present invention is not limited to this example.

  The constant voltage oscillation circuit, for example, generates an alternating voltage having a preset amplitude and period, and supplies electric energy to the piezoelectric vibrator. The waveform of the AC voltage may be, for example, a sine wave having a period similar to the natural period of the piezoelectric vibrator, a sine wave having a period different from the natural period of the piezoelectric vibrator, or a rectangular wave. A triangular wave may be used. Details will be described later.

  FIG. 2A shows an example of the vibration sensor used in the mechanical property measuring apparatus of this embodiment. In this figure, the same parts as those in FIG. As shown in FIG. 2A, in the vibration sensor 12, the piezoelectric vibrator 12a is mounted in an outer casing 127 having an opening. As described above, the piezoelectric vibrator 12a is a two-terminal piezoelectric vibrator. The piezoelectric vibrator 12a is a piezoelectric ceramic vibrator including a rod-shaped piezoelectric ceramic element 122a, a contact 123a, and a pressure spring 124a. The contact 123a is provided at one end in the length direction of the piezoelectric ceramic element 122a, and the pressure spring 124a is provided at the other end in the length direction of the piezoelectric ceramic element 122a. The piezoelectric ceramic element 122a is supported by the exterior casing 127 via the pressure spring 124a. An electrode 125a is formed on one surface of the piezoelectric ceramic element 122a in the length direction, and an electrode 125b is formed on the surface facing the one surface. An electrical terminal 126a is joined to the electrode 125a, and an electrical terminal 126b is joined to the electrode 125b. In this state, a polarization treatment was performed in the same direction as the constant voltage application direction to obtain a two-terminal piezoelectric ceramic vibrator that vibrates due to the piezoelectric transverse effect length longitudinal vibration. In the vibration sensor 12, the piezoelectric ceramic element 122 a is biased toward the opening of the outer casing 127 by the extension of the pressure spring 124 a, and a part of the contact 123 a is part of the outer casing. Projecting from the body 127. In the mechanical property measuring apparatus of the present embodiment, the sensitivity of the piezoelectric vibrator is good, and the current value of the oscillating current to be measured can be increased. As a result, it is possible to measure with high accuracy. Examples of the piezoelectric ceramic element include lead zirconate titanate-based piezoelectric ceramics (PZT) and barium titanate-based piezoelectric ceramics. The piezoelectric vibrator of this embodiment is not limited to the above-described piezoelectric ceramic vibrator, and a conventionally known piezoelectric vibrator can be used.

  For example, the vibration sensor used in the mechanical property measuring apparatus of the present embodiment may have the form shown in FIG. In this figure, the same parts as those in FIG. As shown in FIG. 2B, this vibration sensor is different from the vibration sensor shown in FIG. 2A in that the piezoelectric vibrator includes a plate-like piezoelectric ceramic element 122b. That is, the piezoelectric vibrator 12a is a piezoelectric ceramic vibrator including a plate-like piezoelectric ceramic element 122b, a contact 123b, and a pressure spring 124b. The contactor 123b and the pressurizing spring 124b have shapes that match the shape of the plate-like piezoelectric ceramic element 122b. Except these, it has the same configuration as the vibration sensor shown in FIG.

  In the mechanical property measuring apparatus of the present embodiment, an oscillating current measuring circuit is used as the oscillating current measuring unit, but the present invention is not limited to this example. Moreover, although the said oscillating current measurement circuit is provided with the said electrical filter and the said analysis part, this invention is not limited to this example. Details of the electric filter and the analysis unit will be described later.

  In the mechanical property measuring apparatus of the present embodiment, as described above, the changeover switch having both functions is used as the first switching means and the first switching means. That is, the changeover switch can switch the constant voltage oscillation circuit and the vibration sensor on / off, and can switch the vibration sensor and the vibration current measuring unit on / off. Examples of the changeover switch include an electromagnetic relay type, an electrostatic relay type, and a semiconductor type. For example, a switch control circuit that controls on / off switching of the changeover switch may be electrically connected to the changeover switch.

  Examples of a measurement object for measuring mechanical properties using the mechanical property measuring apparatus of the present embodiment include human skin, animal and plant epidermis, and the like.

  Next, a method of using the mechanical property measuring apparatus of this embodiment will be described based on FIGS. In the method of using the mechanical property measuring apparatus according to the present embodiment, the case where the vibration sensor shown in FIG. 2A is used as the vibration sensor will be described as an example. The method for using the mechanical property measuring apparatus of the present embodiment includes a contact process, an electrical energy supply process, an electrical energy supply stop process, and an oscillating current measurement process. 3 (a) shows the contact process, FIG. 3 (b) shows the electrical energy supply process, FIG. 3 (c) shows the electrical energy supply stop process, and FIG. The oscillating current measuring step will be described. 3 (a) to 3 (d), the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.

[Contact process]
First, the contact process will be described. As shown in FIG. 3A, the contact 123 a protruding from the opening of the outer casing 127 is pressed against the measurement object 31 and brought into contact therewith. The pressing spring 124 a contracts due to the pressing force generated at this time, and the portion of the contactor 123 a that protrudes from the opening of the outer casing 127 is pushed toward the inside of the outer casing 127. The measurement object 31 is as described above. In FIG. 3A, for simplification of illustration, the reference numerals shown in FIG. 2A are omitted except for the reference numerals used in the description of the contact step.

[Electric energy supply process]
Next, the electric energy supply process will be described. With the measured object 31 in contact with the piezoelectric vibrator 12a, the changeover switch 14 is switched to the constant voltage oscillation circuit 11 side as shown in FIG. Are electrically connected to the vibration sensor 12. By doing so, for example, a constant voltage having a preset amplitude and period is applied to the piezoelectric vibrator 12a, and electric energy is supplied to the piezoelectric vibrator 12a. The waveform of the voltage applied to the piezoelectric vibrator 12a is, for example, a sine wave having a period similar to the natural period of the piezoelectric vibrator shown in FIG. However, the present invention is not limited to this example. Examples of the waveform include a sine wave having a period different from the natural period shown in FIG. 4B, a rectangular wave shown in FIG. 4C, and FIG. Are not limited to a specific waveform. FIG. 4 shows a case where a constant voltage is applied to the piezoelectric vibrator 12a for a predetermined time (t1). In FIG. 3B, for the sake of simplification of illustration, the measurement object 31 brought into contact with the piezoelectric vibrator 12a is not shown. The same applies to FIGS. 3C and 3D. The on / off switching of the changeover switch may be performed manually, for example, or may be automatically performed using the control circuit when the switch control circuit is provided.

  The supplied electric energy is converted into vibration energy by the piezoelectric effect of the piezoelectric vibrator 12a. Due to this vibration energy, the piezoelectric vibrator 12a and the measurement object 31 vibrate. When the constant voltage having the waveform shown in FIG. 4A is applied, for example, as shown in FIG. 5A, the amount of vibration energy is temporally changed during the predetermined time (t1). Amplified and accumulated in the piezoelectric vibrator 12 a and the measurement object 31. FIG. 5A shows a waveform obtained by measuring the amount of vibration energy as a vibration current proportional to the vibration energy. Also, when applying the constant voltage having the waveform shown in FIGS. 4B to 4D, as shown in FIGS. 5B to 5D, the predetermined time (t1) is applied. Meanwhile, the amount of vibration energy is amplified in time and accumulated in the piezoelectric vibrator and the measurement object. The setting of the predetermined time (t1) may be performed manually or automatically, for example. In the case of performing automatically, for example, a time set at the time of past use may be stored, and the time may be used repeatedly.

[Electric energy supply stop process]
Next, the electric energy supply stop process will be described. After the elapse of the predetermined time (t1), the constant voltage oscillation is performed by switching the changeover switch 14 as shown in FIG. 3C in a state where the measurement object 31 is in contact with the piezoelectric vibrator 12a. The electrical connection between the circuit 11 and the vibration sensor 12 is disconnected. In this way, the supply of the electric energy is stopped. The accumulated vibration energy is attenuated according to the elapsed time due to the internal friction of the measurement object 31 from the time when the supply of the electric energy is stopped.

[Vibration current measurement process]
Next, the oscillating current measurement process will be described. After the supply of the electric energy is stopped, the changeover switch 14 is switched to the electric filter 16 side to electrically connect the vibration sensor 12 and the electric filter 16 as shown in FIG. By doing so, the accumulated vibration energy is converted into electric energy by the piezoelectric effect of the piezoelectric vibrator. This electric energy is measured by the oscillating current measuring circuit 13 as an oscillating current that attenuates in accordance with the elapsed time (time damped oscillating current) according to the combined mechanical characteristics of the piezoelectric vibrator and the measurement object. . The waveform of the time-damped oscillating current indicates a waveform of a composite wave including a fundamental wave component and a harmonic component having a plurality of natural periods. The waveform of the time-damped oscillating current can be observed with, for example, an oscilloscope.

  In the mechanical property measuring apparatus of the present embodiment, first, the synthesized wave is separated into each waveform component using the electric filter 16. Next, the separated waveform components are analyzed using the analysis unit 17. The analysis is performed by, for example, a digital central processing circuit. As the electric filter 16, for example, a digital filter having a steep cutoff characteristic is used. FIG. 6A shows the waveform of the fundamental component (solid waveform) among the waveforms separated by the electric filter 16. In FIG. 6A, in order to make it easy to understand that the oscillating current is attenuated, a waveform (dashed waveform) indicating the accumulation of the oscillating current in the electric energy supply process is also shown. FIG. 6B shows a second harmonic component (solid waveform) among the waveforms separated by the electric filter 16. Except this, it is the same as FIG. In the mechanical characteristic measuring apparatus of the present embodiment, the waveform components (fundamental wave component, second harmonic component, etc.) separated using the electric filter are analyzed, but the present invention is not limited to this. For example, if the synthesized wave can be analyzed, the electric filter may not be provided. Also, the time-damped oscillating current having the same waveform as in FIG. 6A is generated by the accumulated vibration energy shown in FIGS. 5B to 5D, for example.

  In the mechanical characteristic measuring apparatus of the present embodiment, the natural period and the amplitude value attenuation change are analyzed from the harmonic components such as the fundamental wave component and the second harmonic component, for example, using the analysis unit 17. . FIG. 6C shows an example of analyzing the natural period of the fundamental wave component and the amount of attenuation of the oscillating current amplitude value. As shown in the figure, the analysis of the fundamental wave component is started after a predetermined time (t2) after the time-damped oscillation current is generated. Here, the first waveform 61 that appears first after the start of analysis is the first waveform 61, the second waveform that appears second is the second waveform 62, and the third waveform that appears third is the third waveform. Waveform 63 and the fourth positive waveform appearing as fourth waveform 64. The same applies to the positive waveform (fifth waveform) after the fifth waveform, although not shown. For these waveforms, the maximum value of the current amplitude value and the elapsed time indicating the maximum value are measured. By this measurement, for example, the maximum value of the current amplitude value of the first waveform 61 is I (1), and the elapsed time indicating the maximum value is T (1). Similarly, the maximum value of the current amplitude value of the second waveform 62 is I (2), and the elapsed time indicating the maximum value is T (2). The maximum value of the current amplitude value of the third waveform 63 is I (3), and the elapsed time indicating the maximum value is T (3). The maximum value of the current amplitude value of the fourth waveform 64 is I (4), and the elapsed time indicating the maximum value is T (4). The same applies to the fifth and subsequent waveforms. In FIG. 6C, the maximum value of the current amplitude value after the second waveform 62 is not shown for simplification of illustration.

  The natural period (ΔT) of the time-damped oscillating current can be calculated from, for example, T (2) −T (1). The natural period calculated in this way is assumed to be ΔT (1). Similarly, ΔT (2) is calculated from T (3) −T (2), and ΔT (3) is calculated from T (4) −T (3). The same calculation is performed for the fifth and subsequent waveforms. By taking the addition average of ΔT (1), ΔT (2), ΔT (3), etc., for example, ΔT can be obtained with high accuracy even if sudden external noise is mixed.

  The amplitude value attenuation change (ΔI) of the time-damping oscillating current can be calculated from, for example, I (2) −I (1). The amplitude value attenuation change calculated in this way is defined as ΔI (1). Similarly, ΔI (2) is calculated from I (3) −I (2), and ΔI (3) is calculated from I (4) −I (3). The same calculation is performed for the fifth and subsequent waveforms. As described above, the time-damped oscillating current is an oscillating current obtained according to the combined mechanical characteristics of the piezoelectric vibrator and the measurement object. Since the piezoelectric vibrator has a predetermined mechanical characteristic, measuring the time-damped oscillating current directly measures the mechanical characteristic of the measurement object. Therefore, it is possible to measure the mechanical characteristics of the measured object by calculating the natural period and the amplitude value attenuation change of the time-damped oscillating current using the mechanical characteristic measuring apparatus of the present embodiment.

Further, if a time interval in which the I (1) becomes 1/2 (1 / 2I (1)) is ΔT ⁵⁰ , the mechanical properties of the measurement object are expressed by ΔT and ΔT ⁵⁰ , for example. Can do. ΔT and ΔT ⁵⁰ of the piezoelectric vibrator in a state where it is not in contact with the object to be measured are referred to as ΔT1 and ΔT1 ⁵⁰ , respectively. From the aforementioned ΔT and ΔT ⁵⁰ and ΔT1 and ΔT1 ⁵⁰ , for example, using the digital central processing circuit, ΔT / ΔT1 and ΔT ⁵⁰ / ΔT1 ⁵⁰ are calculated and set as standard values. In the mechanical property measuring apparatus of the present embodiment, for example, the mechanical property of the measurement object can be evaluated using this standard value.

Thus, the effect exhibited by the mechanical property measuring apparatus of the present embodiment for measuring the mechanical property of the measurement object is as follows.
First, the amplitude value attenuation change used for the measurement is due to the internal friction of the measurement object, as described above. This amplitude value attenuation change does not depend on the shape of the measurement object. Therefore, when the natural period of the piezoelectric vibrator itself and the natural period according to the combined mechanical characteristics of the piezoelectric vibrator and the measurement object are close to each other, or the mechanical characteristics of the piezoelectric vibrator and the measurement Even when the difference from the mechanical properties of the object is large, it is possible to measure the amplitude value attenuation change. Thereby, for example, it is not necessary to prepare a plurality of optimized piezoelectric vibrators in order to accurately measure each part such as a person's cheek, chin, arm, and foot that have different mechanical characteristics as a measurement object.
Secondly, the natural period of the time-damped oscillating current depends on the shape, density, elastic modulus and the like of the measurement object as described above. As described above, when the pressing pressure of the user's piezoelectric vibrator changes, this change causes a change in the current amplitude width value. However, the natural period of the time-damped oscillating current is affected by the pressing pressure. Absent.
Thirdly, the mechanical characteristic measuring apparatus according to the present embodiment does not need a self-excited oscillation circuit and does not need to be continuously driven until the measurement is completed. For this reason, it is possible to suppress a change in mechanical characteristics of the piezoelectric vibrator due to heat generated by the piezoelectric vibrator. Moreover, since the mechanical characteristic measuring apparatus of this embodiment does not require a self-excited oscillation circuit, the measurement time delay due to feedback does not occur. For this reason, the measurement error due to the delay does not occur.
Further, in the use of the mechanical property measuring apparatus of the present embodiment, if the second harmonic component shown in FIG. 6B is used for the analysis, the resolution is improved because of the short wavelength. For this reason, for example, when measuring the mechanical properties of human skin, it is particularly effective for measuring minute changes in mechanical properties such as changes in human skin tissue due to adhesion and absorption of oil.
The mechanical property measuring apparatus of the present embodiment that exhibits these effects can measure the mechanical properties of the measurement object with high accuracy. Moreover, the mechanical property measuring apparatus of this embodiment is highly convenient due to the first effect.

  In addition, as described above, the mechanical property measurement apparatus of the present embodiment does not require a self-excited oscillation circuit, and does not need to be continuously driven until the measurement is completed. For this reason, the mechanical characteristic measuring apparatus of this embodiment has low power consumption. Further, since a self-excited oscillation circuit is not required, the size can be reduced, and for example, it can be mounted on a portable electronic device such as a mobile phone or a notebook computer. Accordingly, the mechanical property measuring device of the present embodiment can be a battery-driven and portable device, for example.

  In the mechanical property measuring apparatus according to the present embodiment, for example, the piezoelectric vibrator may be a three-terminal piezoelectric vibrator. FIG. 7A shows the configuration of an example of this mechanical property measuring apparatus. In this figure, the same parts as those in FIG. As shown in FIG. 7A, the mechanical property measuring apparatus 70 includes a first electrical switch 74 and a second electrical switch 75 instead of the above-described changeover switch. The constant voltage oscillation circuit 11 is electrically connected to the vibration sensor 72 via the first electric switch 74. The vibration sensor 72 is electrically connected to the electric filter 16 via the second electric switch 75. The piezoelectric vibrator 72a is a three-terminal piezoelectric vibrator. Except for these points, the mechanical property measuring device 70 has the same configuration as the mechanical property measuring device 10 described above. The first electrical switch 74 and the second electrical switch 75 are switches that can be switched (on / off switched) between connection and disconnection between the above-described components. In this mechanical property measuring apparatus, the first electric switch and the second electric switch are external switches, but the present invention is not limited to this example. For example, the first electrical switch may be disposed in the constant voltage oscillation circuit, and the second electrical switch may be disposed in the oscillating current measurement circuit, as long as the above-described function is provided. It may be.

  FIG. 7B shows an example of the vibration sensor used in this mechanical property measuring apparatus. In the figure, the same parts as those in FIG. As shown in FIG. 7B, in the vibration sensor 72, the piezoelectric vibrator 72a is mounted in an exterior housing 727 having an opening. As described above, the piezoelectric vibrator 72a is a three-terminal piezoelectric vibrator. The piezoelectric vibrator 72 a is a piezoelectric ceramic vibrator including a rod-shaped piezoelectric ceramic element 722, a contact 723, and a pressure spring 724. The contact 723 is provided at one end in the length direction of the piezoelectric ceramic element 722, and the pressure spring 724 is provided at the other end in the length direction of the piezoelectric ceramic element 722. The piezoelectric ceramic element 722 is supported on the exterior casing 727 via the pressure spring 724. An electrode 725a is formed on one surface of the piezoelectric ceramic element 722 in the length direction, and an electrode 725b and an electrode 725c are formed on the surface facing the one surface. An electrical terminal 726a is joined to the electrode 725a, an electrical terminal 726b is joined to the electrode 725b, and an electrical terminal 726c is joined to the electrode 725c. In this state, a polarization treatment was performed in the same direction as the application direction of the constant voltage, and the piezoelectric lateral effect length was made to be a three-terminal piezoelectric ceramic vibrator that vibrates by longitudinal vibration. In the vibration sensor 72, the piezoelectric ceramic element 722 is biased in the direction of the opening of the outer casing 727 by the extension of the pressure spring 724, and a part of the contact 723 is part of the outer casing. Projecting from the body 727. The piezoelectric ceramic element is the same as, for example, the above-described two-terminal piezoelectric vibrator.

  In this mechanical property measuring apparatus, the first electrical switch is used as the first switching means, but the present invention is not limited to this example. As described above, the first electrical switch may be any switch as long as the constant voltage oscillation circuit and the vibration sensor can be switched on and off, and a conventionally known electrical switch can be used. Examples of the first electric switch include an electromagnetic relay type, an electrostatic relay type, and a semiconductor type.

  In this mechanical property measuring apparatus, the second electrical switch is used as the second switching means, but the present invention is not limited to this example. As described above, the second electric switch may be any switch as long as the vibration sensor and the vibration current measuring unit can be switched on and off, and a conventionally known electric switch can be used. As the second electrical switch, for example, the same one as the first electrical switch can be used. The first electrical switch and the second electrical switch may be the same or different. The first electric switch and the second electric switch may be electrically connected to, for example, a switch control circuit that controls on / off switching of the both electric switches.

This mechanical property measuring apparatus can be used, for example, as shown in FIG. That is, first, with the object to be measured in contact with the piezoelectric vibrator 72a, as shown in FIG. 8A, the first electric switch 74 is turned on and the second electric switch 75 is turned off. Thus, the constant voltage oscillation circuit 11 and the vibration sensor 72 are electrically connected. By doing in this way, the above-mentioned electric energy supply process is implemented.
Next, with the measurement object in contact with the piezoelectric vibrator 72a, as shown in FIG. 8B, the first electrical switch 74 is turned off, and the constant voltage oscillation circuit 11 and the vibration sensor are turned on. The electrical connection with 72 is cut off. By doing in this way, the above-mentioned electrical energy supply stop process is implemented. In this step, the second electric switch 75 remains off.
Next, as shown in FIG. 8C, the second electrical switch 75 is turned on to electrically connect the vibration sensor 72 and the electrical filter 16. By doing in this way, the above-mentioned oscillating current measurement process is carried out. Other than these, it can be used similarly to the above-described mechanical property measuring apparatus 10. In the mechanical property measuring apparatus, detailed description of the contact process described above is omitted. Further, on / off switching of the first electrical switch and the second electrical switch may be performed manually, for example, and when the switch control circuit described above is provided, the control circuit is used. It may be done automatically. The on / off switching of the both electrical switches may be performed in conjunction with the switch control circuit, for example.

  Also in this mechanical property measuring device, the mechanical property of the measurement object can be measured with high accuracy, as in the above-described mechanical property measuring device 10. As described above, since the above-described mechanical property measuring apparatus 10 uses a two-terminal piezoelectric vibrator as the piezoelectric vibrator, the sensitivity of the piezoelectric vibrator is better, and the current value of the vibration current to be measured is It is more preferable because it can be further increased.

(Embodiment 2)
FIG. 9 shows a configuration of an example of the mechanical property measuring apparatus of the present embodiment. In this figure, the same parts as those in FIG. As shown in FIG. 9, the mechanical property measuring device 90 has the same configuration as the mechanical property measuring device 10 described above except that it further includes a calculation unit 91 and a reference data storage device 92. That is, the mechanical characteristic measuring apparatus 90 includes a constant voltage oscillation circuit 11, a vibration sensor 12 equipped with a piezoelectric vibrator 12a, a vibration current measurement circuit 13, a changeover switch 14, a calculation unit 91, and a reference data storage. Device 92. The oscillating current measurement circuit 13 includes an electric filter 16 and an analysis unit 17. The analysis unit 17 and the reference data storage device 92 are electrically connected to the calculation unit 91. The reference data storage device 92 stores reference data. In the mechanical property measuring apparatus according to the present embodiment, the calculation unit and the reference data storage device are independent components, but the present invention is not limited to this example. The calculation unit and the reference data storage device may be mounted in the oscillating current measurement circuit, for example.

  The arithmetic unit includes, for example, a digital central processing circuit.

  In the mechanical property measuring apparatus of this embodiment, the reference data storage unit is a reference data storage device. As the reference data storage device, a conventionally known recording device can be used. Examples of the reference data storage device include a semiconductor memory, a magnetic storage device, and an optical storage device.

Examples of the reference data include data obtained by measuring the piezoelectric vibrator used for measurement, data obtained by measuring an object that can be measured (for example, human skin), mechanical properties of human skin, and human health. For example, data indicating a correlation with the state. Examples of the measurement data of the object that can be measured include the natural period (ΔT), the amplitude value attenuation change (ΔI), and the time interval (ΔT ⁵⁰ ) in which the maximum value of the amplitude is halved. . Examples of the measurement data of the piezoelectric vibrator used for the measurement include the above-described natural period (ΔT1), the time interval (ΔT1 ⁵⁰ ) in which the maximum value of the amplitude is ½, and the like. These data may be stored in advance in the reference data recording device at the time of manufacturing the mechanical property measuring apparatus of the present embodiment, or may be stored in the reference data recording device by a user downloading from the Internet or the like. May be.

  Next, a method for using the mechanical property measuring apparatus of the present embodiment will be described. The method for using the mechanical property measurement apparatus of the present embodiment includes a contact process, an electrical energy supply process, an electrical energy supply stop process, an oscillating current measurement process, and a data comparison process. The contact step, the electric energy supply step, the electric energy supply stop step, and the oscillating current measurement step can be performed, for example, in the same manner as the mechanical property measuring apparatus 10 described above.

[Data comparison process]
After measuring the mechanical properties of the measured object using the mechanical property measuring device of the present embodiment in the same manner as the mechanical property measuring device 10 described above, in this step, the data obtained by the measurement and the reference data storage are stored. The calculation unit compares and evaluates the reference data stored in the apparatus. The comparison and evaluation are performed by the digital central processing circuit, for example. Specifically, for example, at least one of ΔT, ΔI, and ΔT ⁵⁰ of human skin measured by using the mechanical property measuring apparatus of the present embodiment and a plurality of known ΔT, ΔI, and ΔT included in the reference data. Compare and evaluate at least one of ⁵⁰ . In this way, for example, the health condition of the skin can be evaluated. You may display this evaluation result by providing a display part in the mechanical characteristic measuring apparatus of this embodiment. The reference data storage device may store measurement data such as ΔT, ΔI, and ΔT ⁵⁰ measured as described above. By storing and accumulating measurement data in this way, it is possible to measure mechanical characteristics with higher accuracy.

  As described above, the mechanical property measuring apparatus of the present invention has high measurement accuracy and low power consumption. Accordingly, examples of the use of the mechanical property measurement apparatus of the present invention include a skin age calculation apparatus and a skin health condition determination apparatus. However, its use is not limited and can be applied to a wide range of fields.

  Next, examples of the present invention will be described together with comparative examples. The present invention is not limited or restricted by the following examples and comparative examples.

[Example 1]
A mechanical property measuring apparatus 10 shown in FIG. 1 was produced. Below, the structure of the mechanical characteristic measuring apparatus 10 used in Example 1 is demonstrated.

[Production of mechanical property measuring device]
(1) Production of Vibration Sensor A vibration sensor shown in FIG. A rod-shaped lead zirconate titanate-based piezoelectric ceramic (PZT, length 5 mm × width 5 mm × height 30 mm) was used as the piezoelectric ceramic element 122a. Ag electrodes 125a and 125b (thickness: 5 μm) were formed on two opposing surfaces of the piezoelectric ceramic element 122a in the height direction. An electrical terminal 126a is joined to the electrode 125a, and an electrical terminal 126b is joined to the electrode 125b. In this state, a polarization treatment was applied in the same direction as the constant voltage application direction, and the piezoelectric lateral effect length was made to be a two-terminal piezoelectric ceramic vibrator 12a that vibrates due to longitudinal vibration. A hemispherical contactor 123a (material: aluminum) was attached to one end in the height direction of the two-terminal piezoelectric ceramic vibrator 12a. A pressure spring 124a (material: hard steel wire) was attached to the end opposite to the one end. The piezoelectric ceramic vibrator 12a was attached in the exterior casing 127 via the pressure spring 124a. In this way, the vibration sensor 12 was produced.

(2) Connection of each component The electromagnetic relay switch as the changeover switch 14 was connected to the electrical terminal 126b of the vibration sensor 12. The constant voltage oscillation circuit 11 and the vibration sensor 12 can be connected via the changeover switch 14. Further, the vibration sensor 12 and the Butterworth type digital filter (electric filter 16) can be connected via the changeover switch 14. The electric filter 16 and the analysis unit 17 were electrically connected. An oscilloscope was connected to the oscillating current measuring unit 13 for oscillating current measurement (not shown). In this way, the mechanical property measuring apparatus 10 of this example was produced.

[Measurement of mechanical properties of piezoelectric ceramic vibrator]
The mechanical properties of the piezoelectric ceramic vibrator 12a of the mechanical property measuring apparatus 10 were measured in advance. First, as shown in FIG. 3B, the changeover switch 14 is switched to the constant voltage oscillation circuit 11 side in a state where it is not in contact with the measurement object, and the constant voltage oscillation circuit 11 and the vibration sensor 12 are switched. And were electrically connected. In this state, a constant voltage (waveform: sine wave, frequency: 50 kHz, voltage value: 1 V) was applied to the piezoelectric ceramic vibrator 12a for 0.1 second. After the application, as shown in FIG. 3C, the changeover switch 14 was switched to disconnect the electrical connection between the constant voltage oscillation circuit 11 and the vibration sensor 12. Next, as shown in FIG. 3D, the changeover switch 14 is switched to the electric filter 16 side to electrically connect the vibration sensor 12 and the electric filter 16. The generated time-damped oscillating current was separated into oscillating currents having respective natural periods by the electric filter (Butterworth type digital filter) 16. In this example, three oscillating currents were extracted in order from the longest natural period among the separated oscillating currents. These three oscillating currents were defined as a first harmonic oscillating current, a second harmonic oscillating current, and a third harmonic oscillating current, respectively. The measurement was started 20 milliseconds after the connection between the vibration sensor 82 and the electric filter 16, and the measurement was continued until the maximum value of the current amplitude value that appeared first was ½. At this time, ΔT1 ⁵⁰ and an average value (ΔT1) of the natural periods ΔT1 (1), ΔT1 (2), ΔT1 (3)... Were measured. This measurement was repeated 100 times.

[Use of mechanical property measuring equipment]
As shown in FIG. 3 (a), the contact 123a of the piezoelectric ceramic vibrator 12a is brought into contact with the cheek (measurement object) of a female subject in their 40s, and the same measurement as described above is repeated 100 times. It was. A natural period obtained, and the time interval until the maximum value of the current amplitude value becomes a value of 1/2, was [Delta] T and [Delta] T ^50. These measured data were quantified as ΔT / ΔT1 and ΔT ⁵⁰ / ΔT1 ⁵⁰ as performance evaluation values of the mechanical property measuring apparatus of this example. Table 1 shows the maximum and minimum values of 100 ΔT / ΔT1 and ΔT ⁵⁰ / ΔT1 ⁵⁰ , respectively.

  The measurement was performed in the same manner except that the waveform was a rectangular wave and the frequency was 40 kHz. The results are shown in Table 2.

  The measurement was performed in the same manner except that a commercially available moisturizing solution was applied to the cheek of the subject and measurement was performed after 5 minutes. The results are shown in Table 3.

[Comparative Example 1]
An elastic characteristic measuring apparatus 1000 shown in FIG. 10 was produced. Below, the structure of the elastic characteristic measuring apparatus 1000 used in the comparative example 1 is demonstrated.

[Production of elastic characteristic measuring device]
(1) Production of Vibration Sensor A vibration sensor shown in FIG. 7B was produced. A rod-shaped lead zirconate titanate-based piezoelectric ceramic (PZT, length 5 mm × width 5 mm × height 30 mm) was used as the piezoelectric ceramic element 722. Ag electrodes 725a and 725b (thickness: 5 μm) were formed on two opposing surfaces of the piezoelectric ceramic element 722 in the height direction. An electrode 725c (5 mm × 7 mm) for measuring an oscillating current was formed on the surface on which the electrode 725b was formed. An electrical terminal 726a is joined to the electrode 725a, an electrical terminal 726b is joined to the electrode 725b, and an electrical terminal 726c is joined to the electrode 725c. In this state, a polarization treatment was performed in the same direction as the constant voltage application direction, and the piezoelectric lateral effect length was made to be a three-terminal piezoelectric ceramic vibrator 72a that vibrates by longitudinal vibration. A hemispherical contact 723 (material: aluminum) was attached to one end of the three-terminal piezoelectric ceramic vibrator 72a in the height direction. A pressure spring 724 (material: hard steel wire) was attached to the end opposite to the one end. The piezoelectric ceramic vibrator 72 a was attached in the exterior casing 727 via the pressure spring 724. In this way, a vibration sensor 1002 was produced.

(2) Connection of components The filter amplifier circuit (electric filter) 1006 is electrically connected to the electrical terminal 726b, and the virtual ground type current detection circuit (vibration current measuring circuit) 1003 is electrically connected to the electrical terminal 726c. Connected. The oscillating current measuring circuit 1003 and a constant voltage driving circuit (constant voltage oscillation circuit) 1001 were electrically connected. The constant voltage oscillation circuit 1001 and the electric filter 1006 were electrically connected. In this way, the mechanical property measuring apparatus 1000 of this comparative example in which the above-described constituent members are connected in a loop shape to constitute a feedback self-excited oscillation circuit was manufactured.

[Measurement of mechanical properties of piezoelectric ceramic vibrator]
The natural period of the oscillating current generated in the electrical terminals 726c and T ^2, except that the maximum value of the amplitude value of the vibration current was I ^2, in the same manner as in Example 1, measuring the mechanical properties of the piezoelectric ceramic oscillator did. Note that in the mechanical property measuring apparatus of this comparative example, the oscillating current is not separated by the electric filter, so in this comparative example, only one wavelength component is the measurement target.

[Use of mechanical property measuring equipment]
As shown in FIG. 10B, the natural period of the oscillating current is T, the maximum amplitude value of the oscillating current is I, and these measurement data are T / T ² and I / I ² for this comparison. Example 1 was performed except that it was quantified as the performance evaluation value of the mechanical property measuring apparatus of the example. Table 4 shows the maximum and minimum values of 100 T / T ² and I / I ² , respectively. Further, in the same manner as in Example 1, a commercially available moisturizing solution was applied to the cheek of the subject, and measurement was performed in the same manner as described above after 5 minutes. The results are shown in Table 5.

(Table 1)
Example 1 (sine wave, no moisturizing liquid)
ΔT / ΔT1 ΔT ⁵⁰ / ΔT1 ⁵⁰
1st harmonic maximum 5.0 × 10 ⁻⁷ 0.13
Minimum value 4.2 × 10 ⁻⁷ 0.11
Second harmonic maximum value 4.8 × 10 ⁻⁷ 0.12
Minimum value 4.4 × 10 ⁻⁷ 0.11
Third harmonic maximum value 4.7 × 10 ⁻⁷ 0.11
Minimum value 4.6 × 10 ⁻⁷ 0.11

(Table 2)
Example 1 (rectangular wave, no moisturizing liquid)
ΔT / ΔT1 ΔT ⁵⁰ / ΔT1 ⁵⁰
First harmonic maximum value 5.1 × 10 ⁻⁷ 0.14
Minimum value 4.4 × 10 ⁻⁷ 0.11
Second harmonic maximum value 4.9 × 10 ⁻⁷ 0.13
Minimum value 4.5 × 10 ⁻⁷ 0.11
Third harmonic maximum value 4.8 × 10 ⁻⁷ 0.11
Minimum value 4.7 × 10 ⁻⁷ 0.10

(Table 3)
Example 1 (with sine wave and moisturizing liquid)
ΔT / ΔT1 ΔT ⁵⁰ / ΔT1 ⁵⁰
First harmonic maximum 7.0 × 10 ⁻⁷ 0.26
Minimum value 6.2 × 10 ⁻⁷ 0.20
Second harmonic maximum value 6.8 × 10 ⁻⁷ 0.24
Minimum value 6.6 × 10 ⁻⁷ 0.22
Third harmonic maximum value 6.7 × 10 ⁻⁷ 0.23
Minimum value 6.7 × 10 ⁻⁷ 0.23

(Table 4)
Comparative Example 1 (sine wave, no moisturizing liquid)
T / T ² I / I ²
Maximum value 6.2 × 10 ⁻⁷ 0.75
Minimum value 8.7 × 10 ⁻⁸ 0.20

(Table 5)
Comparative Example 1 (with sine wave and moisturizing liquid)
T / T ² I / I ²
Maximum value 9.0 × 10 ⁻⁷ 0.85
Minimum value 1.0 × 10 ⁻⁸ 0.25

Comparing Table 1 and Table 4, the difference between the maximum value and the minimum value of ΔT / ΔT1 of Example 1 in Table 1 is 20% or less, and the maximum value and the minimum value of ΔT ⁵⁰ / ΔT1 ⁵⁰ The difference from the value is also 20% or less. On the other hand, the difference between the maximum value and the minimum value of T / T ² in Comparative Example 1 in Table 4 is about 7 times, and the difference between the maximum value and the minimum value of I / I ² is about 4 times. is there. From this, it can be seen that the mechanical property measuring apparatus of Example 1 has high measurement accuracy. It can also be seen that the accuracy is further improved as the order of the harmonic components increases.
Comparing Table 3 and Table 5, in Example 1 in Table 3, changes in the mechanical properties of the subject's skin due to the moisturizing liquid are noticeable. On the other hand, in Comparative Example 1 in Table 5, the change in the mechanical properties of the subject's skin due to the moisturizing liquid is buried in the measurement variation (error), and the change cannot be captured.
When Table 1 and Table 2 are compared, the measurement result when the constant voltage waveform is a sine wave and the measurement result when the constant voltage waveform is a rectangular wave are the first of the oscillating current. There is almost no difference in any of the harmonic, the second harmonic, and the third harmonic. That is, it can be seen that the waveform of the constant voltage applied to the piezoelectric vibrator does not affect the measurement accuracy.

10, 70, 90 Mechanical property measuring device 11 Constant voltage oscillation circuit 12, 72 Vibration sensor 12a Two-terminal piezoelectric vibrator (two-terminal piezoelectric ceramic vibrator)
13 Vibration current measurement circuit (vibration current measurement unit)
14 changeover switch (first switching means and second switching means)
16 Electrical Filter 17 Analyzing Unit 31 Measured Object 61 First Waveform 62 Second Waveform 63 Third Waveform 64 Fourth Waveform 72a Three-Terminal Piezoelectric Vibrator (Three-Terminal Piezoelectric Ceramic Vibrator)
74 1st electric switch (1st switching means)
75 Second electrical switch (second switching means)
91 Calculation unit 92 Reference data storage device 122a, 722 Bar-shaped piezoelectric ceramic element 122b Plate-shaped piezoelectric ceramic elements 123a, 123b, 723 Contacts 124a, 124b, 724 Pressure springs 125a, 125b, 725a, 725b, 725c Electrodes 126a, 126b, 726a, 726b, 726c Electrical terminals 127, 727 Exterior casing 1000 Conventional elastic characteristic measuring device 1001 Constant voltage drive circuit 1002 Three-terminal piezoelectric vibrator 1003 Virtual ground current detection circuit 1006 Filter amplification circuit 1008 Contact with measurement object Waveform 1009 when not touched Waveform 1100 when touched with measurement object Conventional skin elasticity sensor 1102 Piezoelectric ceramic cylinders 1103 and 1203 Contact 1104 Spring for pressurization 1107 and 1207 Exterior casing 1200 Skin age Calculation device 1208 Display unit

Claims (13)

A vibration sensor including a piezoelectric vibrator brought into contact with an object to be measured; a constant voltage oscillation circuit that supplies electric energy to the piezoelectric vibrator; a vibration current measuring unit that measures a vibration current generated in the piezoelectric vibrator; A first switching means that can be switched off and a second switching means that can be switched on / off;
The constant voltage oscillation circuit is electrically connected to the vibration sensor via the first switching means;
The mechanical characteristic measuring apparatus, wherein the vibration sensor is electrically connected to the oscillating current measuring unit via the second switching means.   The mechanical characteristic measuring apparatus according to claim 1, wherein the oscillating current measuring unit includes an electrical filter that separates the oscillating current into natural period components. Furthermore, a reference data storage unit storing reference data, and a calculation unit,
3. The mechanical property measuring apparatus according to claim 1, wherein the oscillating current measuring unit and the reference data storage unit are electrically connected to the arithmetic unit.   4. The mechanical property measuring apparatus according to claim 3, wherein the reference data includes measurement data of the piezoelectric vibrator.   5. The mechanical property measuring apparatus according to claim 1, wherein the piezoelectric vibrator is a two-terminal piezoelectric vibrator. The vibration sensor further includes an exterior housing,
The piezoelectric vibrator is a piezoelectric ceramic vibrator including a piezoelectric ceramic element, a contact and a pressure spring,
The piezoelectric ceramic vibrator is disposed in the exterior casing;
The contact is disposed at one end of the piezoelectric ceramic element;
6. The mechanical property measuring apparatus according to claim 1, wherein the pressure spring is disposed at the other end of the piezoelectric ceramic element. Using the mechanical property measuring device according to any one of claims 1 to 6,
Contacting the measurement object with the piezoelectric vibrator;
After the contact, with the first switching means turned on and the second switching means turned off, electric energy is supplied to the piezoelectric vibrator from the constant voltage oscillation circuit, and the piezoelectric vibrator And an electric energy supply step for accumulating vibration energy in the measurement object,
After the accumulation, the supply of the electric energy to the piezoelectric vibrator is stopped by turning off the first switching means and disconnecting the electrical connection between the constant voltage oscillation circuit and the vibration sensor. Electric energy supply stoppage process;
After the stop, by turning on the second switching means and electrically connecting the vibration sensor and the vibration current measuring unit, the vibration current attenuated according to the elapsed time caused by the connection, A method for using a mechanical property measuring apparatus, comprising: an oscillating current measuring step that is measured by the oscillating current measuring unit. The mechanical property measuring device is the mechanical property measuring device according to any one of claims 2 to 6,
8. The method of using a mechanical property measuring apparatus according to claim 7, wherein in the oscillating current measuring step, the oscillating current separated into the natural period components is measured. The mechanical property measuring device is the mechanical property measuring device according to any one of claims 3 to 6,
The method for using the mechanical property measuring apparatus according to claim 7 or 8, further comprising a data comparison step of comparing data obtained by measuring the oscillating current and the reference data.   10. The method of using a mechanical property measuring apparatus according to claim 9, wherein in the data comparison step, natural period data is calculated from the natural period component, and the natural period data is compared with the reference data.   11. The method of using a mechanical characteristic measuring apparatus according to claim 9, wherein, in the data comparison step, amplitude attenuation data is calculated from the natural period component, and the amplitude attenuation data is compared with the reference data.   12. The method of using a mechanical property measuring apparatus according to claim 11, wherein time data indicating a predetermined amplitude attenuation ratio is calculated using the amplitude attenuation data, and the time data is compared with the reference data. The mechanical property measuring device is the mechanical property measuring device according to any one of claims 4 to 6,
13. The method according to claim 9, further comprising an evaluation step of evaluating the measurement object by comparing the measurement data of the oscillating current and the measurement data of the piezoelectric vibrator. How to use the mechanical property measuring device.

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