JPH0843365A - Ultrasonic measuring device - Google Patents

Abstract

PURPOSE:To obtain complex information of a reflection signal from a specimen in a wide frequency band while a high reliability is maintained. CONSTITUTION:An ultrasonic measuring device comprises burst wave generating means 2, 3 to generate a high frequency burst wave with variable frequency, ultrasonic signal transmitting/receiving means 4, 5, 10 which convert the burst wave into an ultrasonic wave and make it incident onto a specimen and also convert the reflected wave into a reception signal, and a phase shift means 14 which has a plurality of frequency characteristics with different frequency ranges and makes phase shift of the reference signal having the same frequency as the high frequency burst wave with any of the frequency characteristics. The arrangement further includes changeover means 13, 15 to generate by changeover the frequency characteristic to be used in phase shift of the reference signal in accordance with the frequency of the high frequency burst wave, a wave detection means to make phase detection of the reception signal with the phase shifted reference signal, a means 1 to store the phase detection output of the detection means, and a driving means 19 which changes in the Z-axis direction the relative distance between the transmitting/receiving means 4, 5, 10 and the specimen 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic measuring device for measuring elastic properties of a minute portion of a sample by using ultrasonic waves.

[0002]

2. Description of the Related Art An ultrasonic wave converged through an acoustic lens is incident on a sample and a necessary reflected wave component is extracted from the sample reflected wave to create an ultrasonic image, or V (Z) of the sample.
An ultrasonic microscope is known as a device that measures a curve to detect elastic properties of a minute portion of a sample.

Although the above-mentioned ultrasonic microscope measures only the intensity of the reflected wave from the sample, the ultrasonic wave for detecting the intensity and phase of the reflected wave in order to obtain more information about the elastic property of the sample. Measuring devices are being considered. An ultrasonic measuring device of this kind is disclosed in JP-A-5-26854.

FIG. 5 is a diagram showing an example of the configuration of an ultrasonic measuring device for detecting the intensity and phase of a sample reflected wave. In this ultrasonic measuring device, the reference signal oscillator 101 always outputs a continuous wave of a constant frequency, and the control unit 103, to which the transmission trigger is input from the computer 102, synchronizes with the transmission trigger to change the frequency of the reference signal oscillator 101. An ON / OFF signal corresponding to a time width of several tens of cycles is sent to the analog switch 104.
Output to.

The analog switch 104 is switched according to ON / OFF of the signal from the control unit 103, and when ON, the signal generated by the reference signal oscillator 101 is output to the circulator 105 to generate a transmission burst signal. This transmission burst signal passes through the circulator 105 and is applied to the transducer 106. The transmission burst wave is electroacoustic converted by the transducer 106 and converted into ultrasonic waves. This ultrasonic wave propagates through the acoustic lens 107 and is incident on the sample 109 placed on the sample stage 108. A space between the acoustic lens 107 and the sample 109 is filled with a coupler liquid 110 for propagating ultrasonic waves.

The reflected ultrasonic wave reflected by the sample 109 propagates again through the coupler liquid 110 and the acoustic lens 107, and is converted into an electric signal by the transducer 106. Hereinafter, this signal is referred to as a received signal. Received signal is circulator 1
It is amplified by the preamplifier 111 through 05 and input to the two multiplication units 112a and 112b.

On the other hand, the multiplication section 112a multiplies the continuous wave output from the reference signal oscillator 101 by the received signal to detect the in-phase component. The other multiplication unit 112b
Then, the continuous wave output from the reference signal oscillator 101
The signal having the 90 ° phase change in 13 is multiplied by the received signal to detect the quadrature phase component.

Here, the signal output from the reference signal oscillator 101 is defined as sin (ωt). Note that ω is frequency and t is time. Since the phase of the received signal is delayed with respect to the transmission due to the elastic properties of the sample, the time of propagation in the acoustic lens and the coupler liquid, and so on, if this phase delay is φ, then Bsi
It can be written as n (ωt−φ). Note that B is the strength of the received signal.

Therefore, the in-phase output u ₁ of the multiplication unit 112a and the quadrature phase output u ₂ of the multiplication unit 112b are as follows. u ₁ (t) = (B / 2) {cosφ-cosφcos (2ωt) -sinφsin (2ωt)} (1) u ₂ (t) = (B / 2) {sinφ + sinφcos (2ωt) -cosφsin (2ωt)} ( 2) Since φ is a constant, sin φ and cos φ are also constants. Therefore, u ₁ and u ₂ have a DC component and a frequency component of 2ω.
in, cos can be taken out.

The 2ω component of the in-phase output of the multiplication unit 112a and the quadrature phase output of the multiplication unit 112b are removed by the low-pass filters 114a and 114b, respectively, and only the DC components corresponding to sin φ and cos φ remain. The A / D converters 115a and 115b convert the detection outputs of the in-phase and quadrature phases into A / D
D conversion is performed, the phase detection output of the sample reflection is converted into a digital signal, and the digital signal is stored in the memory in the computer 102. In the computer 102, sin φ, c of the sample reflection stored
The phase and the reflection intensity are calculated from the osφ component.

The Z scanning unit 116 is the computer 1
A command from 02 changes the distance between the acoustic lens and the sample to adjust focusing and the like. Further, Japanese Patent Laid-Open No. 5-26855 proposes to use a delay unit that delays a reference signal for a certain period of time instead of the phase shift unit 113. If the delay time of the delay unit is Δt, the phase detection output is (B / 2) cosφ (3) (B / 2) cos (φ−ωΔt) (4). , Cos φ can be calculated.

Sin φ = {Bcos (φ−ωΔt) −cos (ωΔt) Bcosφ} / sin (ωΔt) (5) cosφ = {sin (ωΔt) Bcosφ} / sin (ωΔt) (6) Frequency ω and delay time Δt Is known, sin φ,
It means that cosφ can be calculated.

[0013]

However, the above-mentioned conventional ultrasonic measuring device has the following drawbacks.
That is, generally, the resolution of the ultrasonic measurement device increases in proportion to the reciprocal of the used frequency, and the absorption coefficient of the ultrasonic wave increases in proportion to the square of the used frequency. Therefore, it is necessary to select the frequency according to the purpose of use. For example, a high frequency is selected when measuring with high resolution, and a low frequency is selected when measuring the inside of a sample. In addition, it is required that the frequency be variable when measuring the characteristics of waves such as Lamb wave and Sezawa wave that exhibit frequency dispersion in the speed of sound.

However, in the device disclosed in Japanese Patent Laid-Open No. 5-26854, a wave whose phase is changed in the phase shift section is used as a reference wave for phase detection, but a 90 ° hybrid forming the phase shift section is used. The circuit has a limited frequency range that can be used, and is 100M used in general ultrasonic microscopes.
It has a drawback that it cannot fully support a wide band of Hz to several GHz.

Further, in the device disclosed in Japanese Patent Laid-Open No. 5-26855, if a general 50Ω cable is used for the delay section, the frequency band becomes wide, but it may be difficult to set the delay time. For example, if the delay time is such that the phase is delayed by 90 ° at 100 MHz, it becomes 180 ° at 200 MHz. In this case, the denominator of the equations (5) and (6) becomes 0, and the calculation cannot be performed. The same thing 4
00, 600, ... MHz. Also, 500M
The phase delay at Hz is 450 °, but since this is the same measured value as at 90 °, it cannot be determined whether it is 90 ° or 450 °. On the other hand, the phase delay is 90 ° at high frequencies such as 1 GHz.
If the delay time is set so that the above will not occur, the phase delay at 100 MHz becomes only 9 °, and the measured values (B / 2) cosφ and (B / 2) c
The difference from os (φ-Δt) becomes small, and it becomes easy to be affected by noise.

The present invention has been made in view of the above circumstances, and a plurality of phase shift sections or delay sections having different frequency characteristics can be switched and used according to the frequency of the high frequency burst wave, and can be used in a wide frequency range. An object of the present invention is to provide an ultrasonic measurement device capable of phase sensitive detection.

According to the present invention, a phase shifter or delayer to be used from a plurality of phase shifters or delayers having different frequency characteristics can be switched at high speed by a semiconductor switch, and ultrasonic measurement capable of high-speed frequency switching. The purpose is to provide a device. An object of the present invention is to provide an ultrasonic measuring device that can perform phase detection in a wide frequency band with high accuracy and is inexpensive.

[0018]

The present invention has taken the following means in order to achieve the above object. The present invention corresponding to claim 1 is to generate a high frequency burst wave and to change the frequency of the high frequency burst wave, and to convert the high frequency burst wave generated by the burst wave generation means into ultrasonic waves. The ultrasonic high-frequency burst wave having a plurality of frequency characteristics different in frequency range from each other, the ultrasonic wave transmitting / receiving means for converting the reflected wave from the sample into an electric reception signal after being converged on a minute spot and incident on the sample. And a phase shift means for changing the phase of a reference signal having the same frequency as any one of the frequency characteristics, and a switching for switching the frequency characteristics to be used for the phase change of the reference signal in the phase shift means according to the frequency of the high frequency burst wave. Means and a received signal output from the ultrasonic wave transmission / reception means, which is provided with a reference signal whose reference signal is phase-shifted by the phase shifting means. A detection means for detecting the phase with the reference wave,
It comprises a means for storing the phase detection output of the detection means, and a drive means for changing the relative distance between the ultrasonic wave transmission / reception means and the sample in the Z-axis direction with the incident direction of the ultrasonic wave as the Z axis. .

According to a second aspect of the present invention, in the ultrasonic measuring device having the above structure, the burst wave generating means is
The phase shifter includes at least one oscillator that generates a high-frequency continuous wave and whose oscillation frequency is variable, and burst wave conversion means that cuts out the high-frequency continuous wave generated by the oscillator and converts it into a high-frequency burst wave. Is characterized in that a high frequency continuous wave generated by the oscillator is inputted as the reference signal.

According to a third aspect of the present invention, in the ultrasonic measuring device having the above-mentioned configuration, the phase shifting means is provided with a plurality of 90 ° hybrid circuits for changing the reference signal by 90 °.

According to a fourth aspect of the present invention, in the ultrasonic measuring device having the above-mentioned configuration, the phase shift means is constructed by providing a plurality of delay elements for delaying the reference signal for a predetermined time.

According to a fifth aspect of the present invention, in the ultrasonic measuring device having the above structure, the delay element is composed of a cable having an impedance of 50Ω. According to a sixth aspect of the present invention, in the ultrasonic measuring device having the above configuration, the switching means is provided between the input stages of a plurality of 90 ° hybrid circuits or delay elements provided side by side and the burst wave generating means. The input changeover switch, and an output changeover switch provided between the output stages of a plurality of 90 ° hybrid circuits or delay elements provided side by side and the detection means, the output changeover switch interlocking with the input changeover switch. The switch and the output selector switch are semiconductor switches.

[0023]

The present invention has the following effects by taking the above measures. According to the present invention corresponding to claim 1, the frequency characteristic in the phase shifting means is selected from a plurality of frequency characteristics according to the frequency of the high frequency burst wave generated by the burst wave generating means.

When the high frequency burst wave generated by the burst wave generation means is converted into ultrasonic waves by the ultrasonic wave transmission / reception means and transmitted to the sample, the reflected wave is converted into an electrical reception signal by the ultrasonic wave transmission / reception means. Input to the detection means.

On the other hand, the reference signal having the same frequency as the high frequency burst wave generated by the burst wave generating means is input to the phase shifting means through the switching means. This reference signal is phase-shifted by the selected frequency characteristic and is input as a reference wave to the detection means via the switching means.

The detector detects the phase of the received signal using the reference wave, and stores the complex information of the sample reflected wave, which is the phase detection output. The V (Z) curve of the sample is measured by changing the relative distance in the Z direction between the sample and the ultrasonic wave transmitting / receiving means by the driving means and performing phase detection at each position in the Z direction.

According to the present invention corresponding to claim 2, the high frequency continuous wave generated by the oscillator is cut out by the burst wave converting means to create a high frequency burst wave. Further, the high frequency continuous wave generated by the oscillator is input to the phase shifting means as a reference signal.

According to the present invention corresponding to claim 3, by making the frequency characteristics of the individual 90 ° hybrid circuits arranged side by side different, even if the frequency range of one 90 ° hybrid circuit is narrow, the overall frequency range is wide. Can be covered.

According to the present invention corresponding to claim 4, by making the frequency characteristics of the delay elements provided side by side different, it is possible to narrow the frequency range of one delay element and obtain an appropriate phase shift change. , Can cover a wide frequency range as a whole.

According to the present invention corresponding to claim 5, since the delay element constituting the phase shifting means is realized by the cable having the impedance of 50Ω, the phase shifting means can be constructed at a low cost.

According to the present invention corresponding to claim 6, since the input changeover switch and the output changeover switch forming the changeover means are formed of semiconductor switches, the frequency changeover can be performed at an extremely high speed as compared with a mechanical switch. It will be possible.

[0032]

Embodiments of the present invention will be described below. FIG. 1 is a configuration diagram of an ultrasonic measurement device according to a first embodiment of the present invention. In the ultrasonic measurement apparatus of this embodiment, the oscillator 2 generates a continuous wave having a frequency designated by the computer 1,
The semiconductor switch 3 cuts off a part of the continuous wave generated in the oscillator 2 according to the gate width of the burst gate signal. The transmission burst signal cut out by the semiconductor switch 3 is converted into ultrasonic waves by the transducer 4. The transducer 4 is attached to one end surface of the acoustic lens 5.
The acoustic lens 5 transmits the ultrasonic waves converted by the transducer 4 from the concave surface formed on the other end surface and converges the ultrasonic waves on a minute spot. A sample 6 is placed in a water tank 8 on a sample table 7 near the focal point of the acoustic lens 5. The aquarium 8 is filled with coupler liquid 9 for the propagation of ultrasonic waves. The transmission burst signal is input to the transducer 4 via the semiconductor switch 10 for switching between transmission and reception. Further, the reception signal of the sample reflected wave received by the acoustic lens 5 is output to the preamplifier 11 via the semiconductor switch 10. That is, the semiconductor switch 10 switches the input / output of the transducer 4 between the oscillator 2 and the preamplifier 11 based on the transmission / reception switching signal.

The preamplifier 11 has two multiplication units 12a,
12b is connected. In one of the multiplication sections 12a, one of the continuous waves output from the oscillation section 2 is divided into the first
It is input as a reference signal. In the other multiplication unit 12b,
The other of the two continuous waves divided as described above is input as the second reference signal with a 90 ° phase delay.

Here, the continuous wave output from the oscillator 2 is divided into two, and the other is divided into two via the input changeover switch 13, and the 90 ° phase shifter 14 is composed of a 90 ° hybrid.
It is input to one of a, 14b, 14c ... The 90 ° phase shifters 14a, 14b, 14c ... Have different frequency characteristics. The signal that has passed through any of the 90 ° phase shift units 14 passes through the output changeover switch 15 that is interlocked with the input changeover switch 13 and serves as the second reference signal.
You are typing in 2b.

Low-pass filters 16a and 16b are connected to the outputs of the multipliers 12a and 12b, respectively, so as to remove high-frequency components of the input signal. The characteristics of the low-pass filters 16a and 16b are
It is selected so that at least twice the frequency of the continuous wave output by the oscillator 2 can be removed. A / D converters 17a and 17b are provided in the low-pass filters 16a and 16b.
Are connected, and the respective converted outputs are input to the computer 1.

The computer 1 is connected to a control unit 18 for controlling the overall timing, a Z scanning unit 19 for changing the distance between the sample 6 and the acoustic lens 4, and a Z distance measuring unit 20 for measuring the moving distance. The control unit 18 controlled by the computer 1 generates the burst gate signal, the transmission / reception switching signal, and the sampling signals of the A / D conversion units 17a and 17b.

Next, the operation of this embodiment configured as described above will be described. FIG. 2 is a time chart of this embodiment. When the value of the frequency to be generated by the oscillating unit 2 is input to the computer 1, the computer 1 instructs the oscillating unit 2 about the oscillating frequency, and the phase shifting unit 14a having a frequency characteristic corresponding to the oscillating frequency is supplied to 14b, 1
4c ..., and switches 13 and 15 so that the continuous wave passes through the selected phase shift section.

For example, a frequency of 100 MHz is applied to the oscillator 2.
When set to, the frequency characteristic of the phase shifter 14a is 100 to
200 MHz, the frequency characteristic of the phase shifter 14b is 200 to 4
00 MHz, the phase shifter 14c has frequency characteristics of 400 to 80
At 0 MHz, the computer 1 uses the switch 15 so that the switch 13 connects the oscillator 2 and the phase shifter 14a.
Is switched so that the phase shifter 14a and the multiplier 12b are connected.

The oscillating unit 2 always outputs a continuous wave having a constant frequency as shown in FIG. 2A at the frequency set by the computer 1. As shown in FIG. 2B, when a transmission trigger is input from the computer 1 to the control unit 15, the control unit 15 synchronizes with the transmission trigger and the time for several tens of cycles of the frequency of the oscillator 2 shown in FIG. A width ON / OFF signal is transmitted to the analog switch 3, and a switching signal shown in FIG. 2D that is turned on earlier and turned off later than this signal is output to the analog switch 10.

The analog switch 3 turns on / off the signal.
The signal generated by the oscillator 2 is output to the analog switch 10 when the switching is ON corresponding to the FF. The analog switch 10 shown in FIG.
When the burst gate signal shown in (1) is turned on, it is switched to the analog switch 3 side, and when it is turned off, it is switched to the amplifier 11 side. In this way, the transmission burst signal shown in FIG. The transmit bust signal is applied to the transducer 4 through the analog switch 10. The transmission burst signal is electroacoustic converted by the transducer 4 and converted into ultrasonic waves. This ultrasonic wave propagates through the acoustic lens 5, is converged, passes through the coupler liquid 9, and enters the sample 6. The incident ultrasonic wave is reflected by the sample 6, propagates through the coupler liquid 9 and the acoustic lens 5 again, and is converted into a reception signal by the transducer 4.

The received signal passes through the analog switch 10 already switched to the preamplifier 11 side and the preamplifier 1
It is amplified by 1 and input to the multiplication units 12a and 12b. The multiplication unit 12a multiplies the received signal by using the continuous wave output from the oscillator 2 as a reference signal and outputs the result. On the other hand, the continuous wave output from the oscillator 2 is phase-shifted by the phase shift unit 14a selected by the switch 13. Becomes a signal delayed by 90 °, becomes a second reference signal through the switch 15, and becomes a multiplication unit 12b.
The received signal is multiplied by and the result is output.

The frequency transmitted by the oscillator 2 is ω, and the phase delay of the reflected wave is φ. Output of the multiplier 12a and multiplier 12
The outputs of b are low-pass filters 16a and 16b, respectively.
The 2ω component is removed at, and only the DC components corresponding to cos φ and sin φ remain.

The received signal before detection is shown in FIG. 2 (f), the detection output of the low pass filter 16a is shown in FIG. 2 (g), and the output of the low pass filter 16b is shown in FIG. 2 (h). Before detection, the actual received signal includes transmission leakage, lens first reflection, lens second reflection, etc. in addition to sample reflection as shown in FIG. 2F, and is not a continuous wave but a burst wave. The phase detection output is a rectangular wave corresponding to each reflection as shown in FIGS. 2 (g) and 2 (h).

To extract the sample reflection from the above, FIG.
The control unit 18 generates an A / D conversion trigger signal at a timing delayed by a time Td with respect to the transmission trigger as shown in (i), and samples each detection output as a trigger signal of the A / D conversion units 17a and 17b. A / D conversion is performed, the phase detection output of the sample reflected wave is converted into a digital signal, and the digital signal is stored in the memory in the computer 1.

The time delay amount Td of the transmission and A / D conversion trigger signal can be set from the computer 1 to the control unit 18. The Z scanning unit 19 is the computer 1
The distance between the acoustic lens 5 and the sample 6 is changed in response to a command from to adjust focusing and the like.

When performing V (z) measurement, first look at the sample reflection position on the received signal with A /
The D conversion timing Td is adjusted. The Z scanning unit 19 changes the distance between the acoustic lens 5 and the sample 6 and the Z distance measuring unit 20 measures the amount of movement to repeat the above-mentioned processing, and the complex information cos φ and sin φ of the sample reflection are calculated by the computer together with the amount of movement of Z. Take in 1. The timing of A / D conversion changes depending on the distance between the acoustic lens 5 and the sample 6. The amount of Z movement from the measurement start position is Δz, and the timing shift is Δ
Assuming that Td and the speed of sound of the coupler are v, the computer 1 calculates the timing of A / D conversion from the following equation and changes the timing.

ΔTd = 2Δz / v (7) As described above, according to the present invention, the phase shift section can be automatically switched according to the frequency of the high frequency burst signal, and the ultrasonic wave is reflected from the sample over a wide frequency range. Can measure complex information of.

Next, an ultrasonic measuring device according to the second embodiment of the present invention will be described. FIG. 3 is a diagram showing a configuration of a main part of the second embodiment. The present embodiment is an example in which the configuration of the changeover switch of the phase shift unit in the first embodiment described above is modified, and other configurations are the same as those in the first embodiment except the processing contents of the computer 1. Here, only the configuration and operation of the changeover switch of the phase shift unit will be described.

In this embodiment, the phase shifters 14a, 14b, 1
4c includes semiconductor switches 301a and 301b instead of the input changeover switch 13 and semiconductor switches 302a and 302b instead of the output changeover switch 15. Generally, a semiconductor switch used in an ultrasonic microscope for switching frequencies of 100 MHz or higher has 1 input and 2
Since the output is the opposite (depending on the connection state), when switching the three phase shift units as shown in FIG.

That is, one input side semiconductor switch 3
01a has its input terminal connected to the oscillator 2 and its first output terminal connected to the phase shifter 14a. The other input-side semiconductor switch 301b has its input terminal connected to the second output terminal of the input-side semiconductor switch 301a, its first output terminal connected to the phase shifter 14b, and its second output terminal It is connected to the phase shift unit 14c.

Also, one output side semiconductor switch 302
The output terminal of a is connected to the multiplication unit 12, and the first input terminal is connected to the phase shift unit 14a. The other output side semiconductor switch 302b has an output terminal connected to the second input terminal of the output side semiconductor switch 302a, a first input terminal connected to the phase shifter 14b, and a second input terminal connected to the phase shifter. 14c is connected.

Next, the operation of this embodiment will be described. Similar to the first embodiment, the frequency characteristics of the phase shifters 14a, 14b and 14c are 100 to 200 MHz and 200 to 40, respectively.
0 MHz and 400 to 800 MHz.

When 300 MHz is instructed to the computer 1 as the oscillation frequency of the oscillator 2, the computer 1 sets the frequency of 300 MHz in the oscillator 2, and at the same time, the computer 1 outputs the output of the oscillator 2 to the phase shifter 14b. Semiconductor switches 301a, 301 to be input
b, and the semiconductor switch 302a, so that the output of the phase shifter 14b is input as the reference signal of the multiplier 12b.
Switch 302b. After that, by operating in the same manner as in the first embodiment, the complex information of the ultrasonic sample reflection at the frequency of 300 MHz can be obtained.

Next, a frequency of 500 MHz is set from the computer 1 to the oscillator 2, and at the same time, the computer 1 switches the semiconductor switches 301a and 301b so that the oscillator signal is input to the phase shifter 14c.
The semiconductor switches 302a and 302b are switched so that the output of 4c becomes the reference signal of the multiplication unit 12b. After that, the same operation as in the first embodiment is performed, and the complex information of the ultrasonic sample reflection having the frequency of 500 MHz is obtained.

In the above operation, the frequency is alternately switched while the distance between the acoustic lens 5 and the sample 6 is changed by the Z scanning section 19. Switching time of semiconductor switch is several [nsec]
The mechanical switch is several tens [mse
It is very fast as compared with the switching time of c].
Therefore, if there is time to switch the phase shift part with a mechanical switch and measure the complex V (z) curve of one frequency, the complex V (z) curve can be measured at two frequencies or more at one V (z) measurement. A V (z) curve is obtained.

As described above, according to the present embodiment, since a plurality of phase shifters having different frequency characteristics are switched by the semiconductor switch, the frequency can be switched at a high speed, and V ( The z) measurement yields V (z) curves at multiple frequencies.

In this embodiment, the case where the number of phase shift units is three has been described, but the present invention is not limited to this. Any number of semiconductor switches and phase shifters may be added depending on the frequency band to be measured. Further, although there is a case where the switching of the frequency is not fast depending on the oscillating unit, in such a case, it may be considered that a plurality of oscillating units having different oscillating frequencies are switched by the semiconductor switch.

Next, an ultrasonic measuring device according to the third embodiment of the present invention will be described. FIG. 4 is a diagram showing a configuration of a main part of the third embodiment. The present embodiment is an example in which the configuration of the phase shift section in the first embodiment described above is modified, and the other configurations are the same as those in the first embodiment.

In this embodiment, the phase shifter 14 of the first embodiment is used.
Instead of a, 14b, 14c ... Delay units 401a, 401b, 401c ...
・ You are using.

The changeover switch 13 has delay units 401a, 401b, 401c for delaying different times.
.. are connected, and the changeover switch 15 is connected to each output. For example, assuming that the delay unit 401a is used at 100 to 200 MHz, the respective delay amounts are set so that the delay unit 401a delays the phase by 90 ° at 150 MHz. At this time, the phase delay of 100 MHz is 60 ° and 120 ° at 200 MHz. Similarly, if the delay unit 401b is used at 200 to 400 MHz,
The delay unit 401b is set so that the phase is delayed by 90 ° at 300 MHz, 60 ° at 200 MHz, and 1 ° at 400 MHz.
There is a phase delay of 20 °. The delay unit 401c is 400 to 8
When used at a frequency of 00 MHz, the delay unit 401c is set so that the phase is delayed by 90 ° at 600 MHz.
The phase is delayed by 60 ° at 00 MHz and 120 ° at 800 MHz. If each delay unit is composed of a cable of 50Ω, for example, 33.3 cm, 16.7 cm, and 8.3, respectively.
It will be 3 cm long. The respective time delays at this time are 1.66667 [nsec] and 0.833333 [ns.
ec] and 0.4166666 [nsec]. The other structure is the same as that of the first embodiment.

Next, the operation of this embodiment will be described. At the same time that the frequency is set from the computer 1 to the oscillation unit 2, the computer 1 switches the switch 13 so that the continuous wave of the oscillator 2 is input to the delay unit used in the frequency band, and the output of the selected delay unit is multiplied. The switch 15 is switched so as to be the reference signal of the section 12b.

For example, when the frequency is 120 MHz, the switch 13 is switched so that the continuous wave of the oscillator 2 is input to the delay unit 401a, and the switch 15 is switched so that the output of the delay unit 401a of the multiplication unit 12b is input.

The information of the phase detection obtained under such a setting is expressed by equations (3) and (4), where Δt is the delay time of the delay section and ω is the frequency of the oscillation section 2. From the equations (5) and (6), the complex information sin φ, co
It is possible to obtain sφ.

As described above, according to the present embodiment, not only the phase delay function can be provided at a relatively low cost by using the delay section instead of the phase shift section for changing the phase, but also
By switching the delay unit according to the frequency, the phase that changes as in the past is too small and the S / N ratio is bad and the accuracy drops, and the phase change does not exceed 360 ° because the phase change is too large and it is highly accurate. This enables highly reliable measurement.

The present invention is not limited to the above embodiments. In each of the embodiments, the phase detection is performed by using the oscillator signal and the signal obtained by changing the phase thereof as the reference signals. However, as in JP-A-5-26854, three or more reference signals having different phase changes are used. It is also possible to use it for phase detection.

Further, the phase and intensity of the reflected wave are calculated from the phase detection output. The reflected intensity is detected by peak detection,
It is also possible to detect only the phase from the phase detection output. It is also possible to measure the intensity and phase of the two-dimensional reflected wave by repeating the measurement while the two-dimensional scanning is performed with the XY scanning unit. The present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention.

[0067]

As described above in detail, according to the present invention, the phase shift part for changing the phase of the reference wave of the phase detection is switched depending on the frequency of use of the ultrasonic wave. It is possible to obtain the complex information of the reflection signal of.

According to the invention, the switching means is a high-speed semiconductor switch, so that the V-switching can be performed once in a short time.
It is possible to obtain complex V (z) curves at a plurality of frequencies by (z) measurement and obtain a complex ultrasonic image at a plurality of frequencies by performing one two-dimensional XY scan.

Further, according to the invention, the reference wave is used as the reference wave for phase detection by delaying the reference wave for a certain time, and the delay sections having different delay times are switched according to the frequency. Therefore, the phase is very inexpensive. Not only can you make changes,
This is to obtain highly accurate complex information of ultrasonic waves over a wide range of frequencies, which has been impossible with this configuration.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an ultrasonic measurement device according to a first embodiment of the present invention.

FIG. 2 is a time chart showing the operation of the ultrasonic measurement device shown in FIG.

FIG. 3 is a configuration diagram of a main part of an ultrasonic measurement device according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a main part of an ultrasonic measurement device according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of a conventional ultrasonic measurement device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Computer, 2 ... Oscillation part, 4 ... Transducer, 5 ... Acoustic lens, 12a, 12b ... Multiplication part, 13 ...
Input selector switch, 14a to 14c ... Phase shifter, 15
... Output changeover switch, 18 ... Control section, 31a, 31
b ... Input side semiconductor switches, 32a, 32b ... Output side semiconductor switches, 41a-41b ... Delay section.

Claims (6)

[Claims] 1. A burst wave generation means capable of generating a high frequency burst wave and changing the frequency of the high frequency burst wave; and a high frequency burst wave generated by said burst wave generation means converted into ultrasonic waves and converged into a minute spot. An ultrasonic wave transmitting / receiving means for converting the reflected wave from the sample into an electric reception signal and having a plurality of frequency characteristics different in frequency range from each other, and having the same frequency as the high frequency burst wave. Phase shifting means for changing the phase of any of the frequency characteristics of the signal; switching means for switching the frequency characteristics to be used for the phase change of the reference signal in the phase shifting means according to the frequency of the high frequency burst wave; The reference signal whose phase is changed by the phase means is given as a reference wave, and the received signal output from the ultrasonic wave transmitting / receiving means is referred to as the reference signal. Detecting means for phase-detecting using, means for storing the phase-detected output of the detecting means, and Z-axis as the incident direction of ultrasonic waves, and changing the relative distance between the ultrasonic transmitting / receiving means and the sample in the Z-axis direction. An ultrasonic measuring device comprising: a driving unit. 2. The burst wave generating means generates at least one high frequency continuous wave and has an oscillation frequency variable, and a burst for cutting out the high frequency continuous wave generated by the oscillator and converting the high frequency continuous wave into a high frequency burst wave. The ultrasonic measuring device according to claim 1, wherein the ultrasonic wave measuring device comprises a wave converting device, and the high frequency continuous wave generated by the oscillator is input as the reference signal to the phase shifting device. 3. The phase shift means sets the reference signal at 90 °.
The ultrasonic measuring device according to claim 1, wherein a plurality of 90 ° hybrid circuits for changing are provided side by side. 4. The ultrasonic measurement device according to claim 1, wherein the phase shift means is provided with a plurality of delay elements for delaying the reference signal for a predetermined time. 5. The ultrasonic measurement device according to claim 4, wherein the delay element is a cable having an impedance of 50Ω. 6. The switching means comprises a plurality of adjacent 9
Between an input changeover switch provided between an input stage of a 0 ° hybrid circuit or delay element and the burst wave generating means, and between an output stage of a plurality of 90 ° hybrid circuits or delay elements provided side by side and the detection means. 2. The ultrasonic measuring device according to claim 1, further comprising an output changeover switch provided in the same position as the input changeover switch, wherein the input changeover switch and the output changeover switch are semiconductor switches.