JPS59104549A - Ultrasonic microscope - Google Patents

Abstract

PURPOSE:To adjust automatically a scan plane and a sample surface in parallel, by providing a piezoelectric transducer for position detection so as to surround a piezoelectric transducer and detecting the time difference of sample reflected waves and displacing a sample placing face on a basis of this time difference. CONSTITUTION:An ultrahigh-frequency burst wave electric signal is supplied to a piezoelectric transducer 22 for information detection of an ultrasonic transmitting and receiving part from a high frequency pulse generator 2 through a cir culator 3 under the control of a control part 1, and a sample placed on a sample table 31 is scanned with an ultrasonic spot, and reflected waves are processed to display an ultrasonic image on a display part 13. The burst wave signal from the high frequency pulse generator 2 is supplied to piezoelectric transducers 22a-23d for position detection through a circulator to project ultrasonic waves to the sample, and the difference of reception time of sample reflected waves among transducers 23a, 23b, 23c, and 23d is detected, and X and Y-direction adjusting motors 33 and 34 of a goniometer 32 are driven to displace the sample table 31, thereby adjusting the scan plane and the sample surface in parallel automatically.

Description

[Detailed description of the invention] The present invention relates to an ultrasound microscope.

Various types of ultrasonic microscopes have been proposed in the past. 1st
The figure shows the basic configuration of a reflection-type ultrasound microscope, in which a controller 1 controls a high-frequency wave generator 2 to generate ultra-high frequency burst wave electrical signals, which are transmitted via a circulator 8. and supply it to the piezoelectric transducer 4,
The electric signal is converted into an ultrasonic wave G and is projected in the form of a spot onto a sample 8 placed on a sample stage 7 via an acoustic lens (ultrasonic converging lens) 5 and a liquid 6. The acoustic lens 5 and the sample stage 7 are operated by an X-direction scanning section 9 under the control of the control section 1 in order to two-dimensionally scan the sample 8 with an ultrasonic spot.
and the Y-direction scanning unit 10, it is configured to be relatively (two-dimensionally movable).On the other hand, the reflected wave from the sample 8 is
The acoustic lens 5 collects the sound, the piezoelectric transducer 4 converts it into an electrical signal, and the signal is sent to the receiver 11 via the circulator 3.
Here, under the control of the control unit 1, only the signal corresponding to the reflected wave from the sample 8 is extracted, amplified and detected, and this detected signal is used as a luminance signal to be After being recorded in the scan converter 12 together with the position G signal from the Y-direction scanning section 9 and 10, it is displayed as an image on the display section j3.

In such an ultrasonic microscope, the sample 8 needs to be placed at a position where the ultrasonic beam is minimized. That is, it is necessary that the plane created by the scanning of the minimum spot of the ultrasonic beam and the surface of the sample 8 coincide with or be parallel to each other. Therefore, in general, the sample stage 7 is installed on a goniometer that can adjust the parallelism of the surface in two directions, and the surface of the sample 8 is adjusted so that it is parallel to the plane created by scanning the ultrasonic spot. However, in the past, the sample 8 was repeatedly scanned two-dimensionally with an ultrasonic beam, and while observing the image formed on the display section 13, the goniometer was manually adjusted to reduce interference fringes appearing in the image. Because of this, there was an adjustment workbench.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide an ultrasonic microscope suitably configured to automatically and quickly make the plane created by scanning an ultrasonic spot parallel to the sample surface using a simple configuration. It is something to do.

In the present invention, a sample stage on which a sample is placed, a piezoelectric transducer and an acoustic lens provided integrally are moved relative to each other in two dimensions, and ultrasonic waves are spotted from the piezoelectric transducer to the sample via the acoustic lens. In an ultrasonic microscope configured to scan a sample by projecting an ultrasonic beam onto the sample, an ultrasonic transducer is arranged separately from the pressure transducer to surround it, and transmits ultrasonic waves to the sample and receives reflected waves thereof. at least three piezoelectric transducers for position detection; means for detecting a time difference between sample reflected waves detected by each of these piezoelectric transducers for position detection; A plane formed by scanning an ultrasonic spot projected through the acoustic lens and the sample surface are automatically aligned in parallel for one week (f It is characterized by being configured so that

The present invention will be described in detail below with reference to the drawings.

FIGS. 2A and 2B are a plan view and a sectional view showing the configuration of an example of an ultrasonic transmitting/receiving section used in the ultrasonic microscope of the present invention. In this example, the sapphire rod 2 is used as the ultrasonic propagation medium]
A piezoelectric transducer 22 for detecting information is provided at the center of one end surface, and two piezoelectric transducers for detecting iδ are placed in the X and Y directions perpendicular to each other so as to surround the piezoelectric transducer 22. transducer 2
3a; 23b, 23Ci23d are set. The other end surface of the sapphire rod 21 has a central portion facing the piezoelectric transducer 22, and the ultrasonic waves projected from the piezoelectric transducer 22 through the sapphire rod 21 are spot-shaped onto the sample placed on the sample stage G. An acoustic lens 24 is formed which converges two waves and collects the waves reflected from the sample, and at the periphery, ultrasonic waves are projected onto the sample from piezoelectric transducers 23a to 23d through the sapphire rods 21, and the reflected waves are collected. 1. An ultrasonic wave transmitting/receiving section 25 for steam detection is formed.

With this sapphire rod 21 held in the lens holder 26 and opposed to the sample 27 via the liquid 28 as shown in FIG. 3, the piezoelectric transducers 23a to 23a ( In the drawing, the piezoelectric transducer 23a is in the X direction.

When an electric signal is simultaneously supplied to the sapphire rod 21 and the liquid 28 (only 23 'D shown) and ultrasonic waves are projected onto the sample 27, each ultrasonic wave causes the sample 27
The time during which the reflected waves from the sapphire rods 23 and 23 pass through the liquid 28 and the nanofiber 7o7)-21 and are received by the corresponding piezoelectric transducers is determined by
If the lengths between a to 23a and the ultrasonic transducer 25 are made equal, the distance between the ultrasonic transceiver z5 and the sample 27 determines the distance between the piezoelectric transducers 2 that form a pair.
3ai23b, 23c; 23d, there will be a difference in reception time between the two depending on the difference in distance.

For example, as shown in FIG. 3, the sample 27 is tilted in the X direction, and the distances between the transmitting/receiving section 25 and the sample 27 on the piezoelectric transducer 23a and 28b sides become do and d2 (<d), respectively. - Then, the speed of sound in the liquid 28 is 01 Sapphire Rod 21
If the speed of sound within the piezoelectric transducer 23a is ignored, the piezoelectric transducer 23a
In the piezoelectric transuser 23b, the time from the output to the input of the ultrasonic wave is ta = 2d1/c as shown in FIG. 4B, and in the piezoelectric transuser 23b, as shown in FIG.
b = 2d2/C, and a time difference of (1a-tb) corresponding to the distance difference (d knee d2) is generated between them. Therefore, in the X and Y directions, each pair of piezoelectric transducers 23 a i 2
8 b, 23 c; 23 (i) If the difference in reception time in the two directions is detected, the sample 27 in each direction is
The amount of inclination and its direction (polarity) can be known.

FIG. 5 is a perspective view showing the configuration of an example of a sample stage used in the ultrasonic microscope of the present invention. In this example, the sample stage 31 is provided on a goniometer 32, and the goniometer 32 is independently rotated in the X and Y directions via an X-direction adjustment motor 33 and a Y-direction adjustment motor 34, which are rotatable in forward and reverse directions. The sample stage 31 is thereby automatically displaced in the X direction and the Y direction.

In one embodiment of the present invention, in place of the piezoelectric transducer 4 and acoustic lens 5 in the ultrasonic microscope shown in FIG. 1, an ultrasonic transmitting and receiving section shown in FIGS. 7, the configuration shown in FIG. 5 is used. The ultrasonic transmitting/receiving section and the goniometer 32 are relatively two-dimensionally moved by an X-direction scanning section 9 and a Y-direction scanning section 10 under the control of a control section 1 in FIG. Further, under the control of the control unit 1, an ultrahigh frequency burst wave electrical signal is supplied from the high frequency pulse generator 2 via the circulator 3 to the piezoelectric transducer 22 for information detection in the ultrasonic transmitting/receiving unit. Listed i;
The sample to be scanned is scanned by the ultrasonic spot G, and the sample reflected waves are processed in the same manner as in FIG. 1 to display an ultrasonic image on the display section 13.

In this example, a high-frequency burst wave electrical signal generated from a high-frequency pulse generator 2 is supplied to piezoelectric transducers 23a-23(i) for position detection through respective circulators, and ultrasonic waves are projected onto the sample. Piezoelectric transducers 23ai23b form a pair in the X and Y directions of the sample reflected wave.

The difference in reception time at 23Ci23d is detected, and based on the time difference, the X and Y direction adjustment motors 33 and 34 of the goniometer 32 are driven to adjust the sample stage 31.
By displacing the information detection piezoelectric transducer 22711, a plane in which an ultrasonic spot is projected onto the sample through the acoustic lens 24 is formed by scanning;
Automatically adjust the test surface to be parallel to the test surface.

In other words, as shown in FIG. 6 showing the configuration of the adjustment circuit in the X direction, the control pulse shown in FIG. Wave electrical signals are supplied to piezoelectric transducers 23a and 23b for position detection forming a pair in the X direction through circulators 41a and 41b, respectively, to project ultrasonic waves onto the sample.These piezoelectric transducers 2
The sample reflected wave signals received by 3a and 23b are supplied to amplification/detection sections 4.1a and 442b via circulators 4.1a and 4.1b, respectively, and are then supplied to amplification/detection sections 4.1a and 442b, respectively.
and a reflected signal as shown in C is obtained. As explained in Fig. 3 and Fig. 4, these reflected signals are generated at times ta and tb after the ultrasonic wave is emitted, depending on the distance to the sample, and there is a difference between the two. If there is a difference in the ridges, that is, if the sample is tilted in the X direction, a difference will occur in the generation time.
and 43b, respectively.1. This is the standard value V. 7th F2 D and E, and these signals are sent to the sample and hold circuit 4, respectively.
'4a and 441b.

On the other hand, the control pulse shown in FIG. 7A from the control section 1 is also supplied to the integrator 45, which generates a sawtooth waveform voltage as shown in FIG. 7F in synchronization with the control pulse. This sawtooth voltage is applied to the sample and hold circuit 44 & 44k)
The pulse signals (71st JD and E) from the ratios 1i43a and 4ab are sampled and held, and as shown in FIG. 7, G and H, the voltage ( Val Vb)
get the signal. The outputs of these sample and hold circuits 44.a and 44b are supplied to a differential amplifier 47 via a gate circuit 46 at the gate pulse timing synchronized with the control pulse shown in FIG. 7, and the difference between them is detected. The voltage difference detected by the differential amplifier 47 corresponds to the difference in reception time of the sample reflected waves at the piezoelectric transducers 23a and 28b, and its value corresponds to the distance difference to the sample, and its polarity corresponds to the direction of the sample inclination. corresponds to The output of the differential amplifier 47 is supplied to the motor drive section /l18, which drives the goniometer 3.
Drive the X-direction adjustment motor 33 of No. 2 to move the sample stage 31 in the X direction.
Correct the tilt of the sample by displacing it in the direction.

This correction ends when the output of the differential amplifier 47 becomes zero, thereby making it possible to make the plane formed by scanning the ultrasonic spot parallel to the sample surface in the X direction.

The adjustment in the X direction has been explained above, but if the same circuit configuration is used to simultaneously adjust the Y direction, the plane formed by the ultrasonic spot by scanning in the X and Y directions and the sample surface can be automatically and Can be quickly parallelized.

Note that the present invention is not limited to the above-mentioned example, and can be modified or changed in many ways.

For example, there may be three piezoelectric transducers for position detection, and these may be attached separately from the ultrasonic propagation medium to which the piezoelectric transducers for information detection are attached. Further, the present invention is not limited to the above-mentioned reflection type ultrasonic microscope, but can also be effectively applied to a transmission type ultrasonic microscope.

As described above, according to the present invention, the plane formed by scanning the ultrasonic spot and the sample surface can be automatically and quickly adjusted to be parallel to each other. Adjustment work can be omitted.

, 1/If of Figure 1;j Simple explanation Figure 1 shows the basic configuration of a reflection ultrasound microscope. i
! JN Figures 2A and 2B are a plan view and ii5'i[
Fig. n1, Fig. 8, and Fig. 4 A-C are diagrams for explaining its operation; Fig. 5 is a perspective view showing the configuration of an example of a sample stage used in the ultrasonic wave microscope of the present invention; Fig. 6; 7 is a block diagram showing the circuit configuration of a main part of an example of the ultrasonic microscope of the present invention, and FIGS. 7A to 7A are signal waveform charts illustrating its operation.

1... Control unit 2... Local frequency pulse generator 3... Circulator 4... Piezoelectric transducer 5... Acoustic lens 6... Liquid 7.
...Sample stand 8...Sample 9...X-direction scanning unit lO...Y-direction scanning unit 11...Receiver'M
NS 12...Scan converter 1
3...Display section 21...Sapphire rod 22...Piezoelectric transducer for information detection 23a-z
sd... Piezoelectric transducer for position detection 24...
Acoustic lens 25... Ultrasonic transmitter/receiver for position detection 26... Lens holder 27... Sample 28...
Liquid 31... Sample stage 32... Goniometer 38... X direction adjustment motor 34... Y
Direction le' (board motor 41a, 41b...circulator, 1.2a, 42b...amplification/detection section 43a
, 43b... comparator i, 4. a, 44・b・
...Sample hold circuit 45...Integrator
46...Gate circuit 47...Differential amplifier 4+
8...Motor drive part Fig. 2 Fig. 3 Procedure Sleeve Book November 1, 1058 S Day 1: +J display Showa! 1957 q, Teshi''Writ No. 2.111.38
No. 5 No. 2, Name of the invention Ultrasonic microscope 3, Person making the correction + 1 Relationship with the H matter q.
581) No. 2'241 (Representative) 5゜6 Target of amendment Myotsumugi 111, "A, '1.
(As per attached sheet) 1. The scope of claims on page 1, line 3 to page 2, line 2 of the specification are amended as follows.

2. Claim L A sample stage on which a sample is placed, and a piezoelectric transducer and an acoustic lens provided integrally are moved relative to each other in two dimensions. Ultrasonic waves are transmitted from the piezoelectric transducer to the sample via the acoustic lens. In an ultrasonic microscope that scans the sample by projecting it in the form of a spot, this 3
At least three piezoelectric transducers for position detection that transmit ultrasonic waves to the sample and receive their reflected waves, and these position detection pressures
p) Means for detecting a time difference between the reflected waves detected by the tun transducers, and means for displacing the sample mounting surface of the sample stage based on the output of the time difference detecting means, 1. An ultrasonic microscope characterized in that the plane cloth formed into a shape 1 by scanning a projected ultrasonic spot and the sample surface can be automatically adjusted to line F. , 2 Specification @ Section] Page 2, No. 16 to] Line 8, ``The present invention can also be modified from one to one.'' is deleted.

Claims (1)

[Claims] L A sample table on which a sample is placed, a piezoelectric transducer and an acoustic lens provided integrally are moved relative to each other in two dimensions, and ultrasonic waves are transmitted from the piezoelectric transducer to the sample via the acoustic lens. In an ultrasonic microscope that scans the sample by projecting a spot-like beam, the transducer is arranged separately from the piezoelectric transducer to surround the piezoelectric transducer, and transmits ultrasonic waves to the sample and receives the reflected waves thereof. at least three piezoelectric transducers for position detection; means for detecting a time difference between sample reflected waves detected by each of these piezoelectric transducers for position detection; and means for displacing the placement surface, and configured to automatically adjust the plane formed by scanning the ultrasonic spot projected through the acoustic lens to be parallel to the sample surface. ultrasound microscope.