JPH05337140A - Measuring apparatus for degree of oscillation - Google Patents

Abstract

PURPOSE:To provide a measuring apparatus for the degree of oscillation of an artificial root which enables the reducing of the number of probes which are adapted to transmit vibrations in contact with the artificial root to detect the vibrations from the artificial root to one to improve operability while allowing the extracting of a specified frequency band accurately from the vibrations of the artificial root. CONSTITUTION:An ultrasonic vibrator 13 is kept in contact with an object to be measured (artificial root) through a probe 14. The ultrasonic vibrator 13 is supplied with a pulse voltage from a pulse voltage generator 12 and vibrations of the ultrasonic vibrator 13 vibrating according to the pulse voltage are transmitted to the object 15 to be measured. The ultrasonic vibrator 13 detects a vibration component of the object 15 to be measured as well and an electrical signal corresponding to the vibration component is supplied to a data processing section 18 as data processing means through an amplifier 16 and an A/D converter 17. The data processing section 18 performs a time base-frequency base conversion of the electrical signal supplied from the ultrasonic vibrator 13 to detect the degree of oscillation of the object 15 to be measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration degree measuring device suitable for use in measuring the vibration degree representing the fixed state of an artificial tooth root, for example.

[0002]

2. Description of the Related Art An artificial tooth root mobility measuring device is useful for the subsequent treatment by measuring the mobility between the artificial tooth root and the bone, and expressing it by a numerical value.

This measurement principle is to give a minute vibration to an artificial tooth root by a pulse wave passing through an ultrasonic vibrating element and examine what kind of vibration the artificial tooth root makes. For example, by utilizing the fact that there is a correlation between the specific frequency component of the response waveform when a small vibration is applied to the artificial tooth root and the vibration of the artificial tooth root, this specific frequency component is extracted with a filter. , The characteristic of this frequency component is displayed as a numerical value from 1 to 100.

An outline of such a conventional artificial tooth root mobility measuring device is described in Japanese Patent Laid-Open No. 60-190941.

FIG. 4 is a block diagram showing the configuration of an example of such an artificial tooth root movement measuring device. In the figure, a pulse voltage generator 1 supplies a pulsed electric signal to an ultrasonic oscillator 2, and the ultrasonic oscillator 2 is an object to be measured (that is, artificial tooth root) 1
It vibrates in the ultrasonic band including the resonance frequency of 1. The vibration of the ultrasonic oscillator 2 vibrates the DUT 11 via the probe 3. The vibration of the DUT 11 at this time is also transmitted to the ultrasonic probe 4 via the probe 3 and converted into an electric signal there. The detection signal which is the output from the ultrasonic probe 4 is amplified by the amplifier 5, and the bandpass filter (BPF) 6 extracts only a specific frequency region including the resonance frequency of the DUT 11. The signal that has passed through the BPF 6 is smoothed by the smoothing circuit 7, and then the A / D converter 8
Is converted into a digital signal and is given to the CPU 9.
The CPU 9 detects the presence or absence of the resonance phenomenon of the detection signal obtained from the ultrasonic probe 4 and performs the measurement for obtaining the fluctuation degree a suitable number of times, and numerically displays the fluctuation degree on the display unit 10.

[0006]

In the above-described conventional artificial tooth root dynamics measuring device, the operator uses the two probes 3 for vibration and detection to vertically and constant weight the surface of the artificial tooth root. It must be kept in contact for a predetermined time (for example, 1 second). However, it is very difficult to perform such a measurement operation accurately because the diameter of an artificial tooth root is small, about 4 mm to 7 mm, and it is slippery, as well as being dark and narrow in the oral cavity.

Further, since the frequency component useful for measurement and the frequency component not so close to each other are very close to each other, the frequency band to be extracted by the BPF 6 must be set strictly, but the BPF 6 is configured by an analog filter. In that case, the adjustment is extremely difficult, and the frequency characteristic also changes due to changes over time.

The present invention has been made in order to overcome such a conventional problem. A probe for contacting an object to be measured to transmit vibration and detecting the vibration from the object to be measured is provided.
An object of the present invention is to provide a vibration degree measuring device capable of improving operability by using a book and accurately extracting a specific frequency band of vibration of an object to be measured.

[0009]

SUMMARY OF THE INVENTION The motion measuring apparatus of the present invention applies a shock to a measured object (artificial tooth root) 15 by ultrasonic excitation and detects the vibration of the measured object 15.
Ultrasonic transducer 13 as a conversion means for converting into an electric signal
And a data processing unit 18 as data processing means for converting the time axis of the signal output from the ultrasonic transducer 13 into a frequency axis.

[0010]

In the vibration measuring device having the above structure, the ultrasonic transducer 13 is brought into contact with the object to be measured (artificial tooth root) 15 via the probe 14. The ultrasonic oscillator 13 is supplied with the pulse voltage from the pulse voltage generator 12, and the vibration of the ultrasonic oscillator 13 that vibrates according to the pulse voltage is transmitted to the DUT 15. The ultrasonic transducer 13 is the DUT 1
Since the vibration component of No. 5 is detected and exchanged for an electric signal, the electric signal according to this vibration component is supplied to the data processing unit 18. The data processing unit 18 converts the time axis of the electric signal supplied from the ultrasonic transducer 13 into a frequency axis and detects the degree of vibration of the DUT 15.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the artificial tooth root vibration measuring device of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the artificial tooth root mobility measuring device of the present invention. For example, an ultrasonic transducer 13 is brought into contact with a measured object 15 made of an artificial tooth root via a probe 14. And
A high-frequency pulse voltage is supplied from the pulse voltage generator 12 to the ultrasonic transducer 13. When the ultrasonic transducer 13 vibrates the DUT 15, the DUT 15 vibrates accordingly, but the vibration of the DUT 15 is fed back to the ultrasonic transducer 13 at the same time. The ultrasonic transducer 13 converts the fed back vibration of the DUT 15 into an electric signal to generate a detection signal, and the detection signal is amplified by the amplifier 16.

The detection signal amplified by the amplifier 16 is A
Is supplied to the / D converter 17 and converted into a digital signal,
Further, the digitized detection signal is supplied to the data processing unit 18. The data processing unit 18 includes, for example, fast Fourier transform (FFT) means, and the digitized detection signal is converted from the time axis to the frequency axis in the data processing unit 18. Further, the data processing unit 18 measures the vibration degree of the DUT 15 by performing numerical processing on the data of the frequency band including the resonance frequency of the DUT 15 from the frequency spectrum of the detection signal converted into the frequency data, The display unit 1 which is composed of an LCD or the like for the measured fluctuation degree.
Display on 9. The measurement of the degree of vibration by the data processing unit 18 is preferably performed a plurality of times in order to suppress an error due to camera shake or the like.

The control unit 20 controls the peak value, width, generation timing, etc. of the pulse voltage to be generated by the pulse voltage generator 12, and only the response vibration of the ultrasonic transducer 13 from the DUT 15 is data. The timing is controlled so that it is supplied to the processing unit 18.

According to the above construction, since the ultrasonic transducer 13 is used both for exciting the measured object 15 and for detecting the response vibration, only one probe 14 is used for measuring the measured object 15, That is, since it is only necessary to bring the probe into contact with the artificial tooth root, the operability is improved as compared with the conventional case where two probes are brought into contact.

FIG. 2 is a block diagram showing the configuration of an embodiment for explaining the artificial tooth root movement degree measuring device of the present invention in more detail. The same parts as those of the embodiment of FIG. Is added and the description thereof is omitted as appropriate. Also, in FIG.
3 is a timing chart showing output waveforms in each circuit of FIG. 2.

In FIG. 2, the pulse voltage generator 12 is
Under the timing control by the CPU 21, a rectangular pulse voltage having a pulse width of 10 μsec and an amplitude of 5 V as shown in FIG. 3A is repeatedly generated every 10 msec. A memory 24 and a display unit 19 are connected to the CPU 21. The pulse voltage from the pulse voltage generator 12 is applied to the ultrasonic transducer 13
Is converted into a mechanical vibration by means of which the object to be measured 15 is excited via the probe 14. As the ultrasonic transducer 13, for example, a piezoelectric element having a diameter of 3 mm and a stainless rod probe 14 having a diameter of 3 mm and a length of 10 mm adhered thereto is used.

The vibration generated in the object to be measured 15 is simultaneously converted into an electric signal by the ultrasonic vibrator 13. The vibration converted here is separated into a self-excited vibration portion and a response vibration signal portion by the analog switch 22 in order to eliminate the influence of the pulse voltage for the self-excited vibration of the ultrasonic transducer 13, and only the response vibration signal is generated. Is processed as a detection signal in the subsequent stage. Therefore, the analog switch 22 is controlled by the CPU 21, is closed at the timing when the pulse voltage generated by the pulse voltage generator 12 is applied to the ultrasonic transducer 13, and is opened after the application of the pulse voltage is completed. It
Since the detection signal (FIG. 3B) obtained here is weak, it is amplified 1000 times by the amplifier 16, for example.

The amplified detection signal is supplied to the anti-aliasing filter (AAF) 23, and the frequency component of 1/2 or less of the sampling frequency of the A / D converter 17 is cut. For example, when the sampling cycle of the A / D converter 17 is 5 μsec, the AAF 23 is a low pass filter having a cutoff frequency of 100 kHz or less. Then, the detection signal is supplied to the A / D converter 17 and converted into a digital signal. As shown in FIG. 3C, this conversion is performed so that 128 samplings are performed at intervals of 5 μsec, for example.

The sampled value is converted to A / D by the A / D converter 17.
The data that has been D-converted and A / D-converted is the data processing unit 1.
8, the time axis is converted into a frequency axis, and a frequency spectrum is obtained. The calculation for the time axis-frequency axis conversion may be performed by the CPU 21, or may be performed there by using a digital signal processor (DSP) as the data processing unit 18.

For this calculation, a Fourier transform within an appropriate window is used. For example, in the case of the sampling timing as shown in FIG.
By performing FT, frequency data (frequency spectrum) in the range of approximately 1 kHz to 100 kHz can be obtained. At this time, information such as the sensitivity and frequency characteristics of the ultrasonic vibration element 13 is stored in the memory 24, and the frequency spectrum is corrected using this information. Memory 24
The adjustment work can be facilitated by using a non-volatile memory such as an EEPROM.

In the thus obtained frequency spectrum, a certain specific frequency region (for example, 10 to 20 k)
(Hz) component, and the degree of fluctuation is calculated from it. This fluctuation degree is set to be "1" when the best model (measurement object) is measured and "100" when the worst model is measured.

In order to eliminate the influence of camera shake or the like at the time of measurement, after performing this measurement a plurality of times, the average and standard deviation are obtained, and when the measurement is stable, the display unit 19 displays the degree of vibration.

The case where the present invention is used in the artificial tooth root mobility measuring device has been described above as an example, but the present invention can also be applied to the case where the object other than the artificial tooth root is measured for its mobility. ..

[0024]

As described above, according to the vibration degree measuring device of the present invention, the conversion means is used both for exciting and detecting the object to be measured, and the time of the detection signal corresponding to the vibration of the object to be measured. Since the axis is converted into the frequency axis, conventionally, it is necessary to bring two probes into contact with the object to be measured, but only one probe needs to be brought into contact with the object to be measured, which improves operability.
Further, since the change on the time axis is detected, it becomes easy to separate the signal component in the predetermined frequency band, the configuration for that becomes simple, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a shaking degree measuring device of the present invention.

FIG. 2 is a block diagram showing the configuration of another embodiment of the shaking degree measuring device of the present invention.

FIG. 3 is a timing chart explaining the operation of the embodiment of FIG.

FIG. 4 is a block diagram showing a configuration of an example of a conventional artificial tooth root mobility measuring device.

[Explanation of Codes] 12 Pulse Voltage Generator 13 Ultrasonic Transducer (Conversion Means) 14 Probe 15 Object to be Measured 16 Amplifier 17 A / D Converter 18 Data Processing Section (Data Processing Means) 19 Display Section 20 Control Section 21 CPU 22 analog switch 23 anti-aliasing filter

Claims (1)

[Claims] 1. A converter for applying a shock to an object to be measured by ultrasonic excitation, detecting the vibration of the object to be measured, and converting the electric signal into an electric signal, and a time axis of a signal output from the converter. A fluctuation measuring device, comprising: a data processing means for converting the frequency axis.