JPS6110765A - Ultrasonic microscope - Google Patents

Abstract

PURPOSE:To enable accurate measurement of dimensions and position in a sample while correctly determining changes inside the sample, by providing a transmitter which is capable of applying a high frequency current to a piezo- electric thin film of a lens, a receiver for receiving an electrical signal or the like. CONSTITUTION:A transmitter 7 is provided with switches (SW)20a and 20c connectable to a planar sound wave lens 1 or a spherical sound wave lens 2 while a receiver 8 is provided with switches 20b and 20d in such a manner as to be allowed to receive a signal from either of the lenses 1 and 2. To detect an internal hollow or a flaw of a sample 6, the switches SW 20a and 20c are connected to a transmitter 7 so as to set the lens 2 to the transmitting position while the lens 1 is connected to a receiver 8 by changing over the switches 20b and 20c to turn the lens 1 to the receiving position. Then, a hollow or a defect in a sample 6 is detected accurately. On the other hand, to find the defect and the positional relationship, the connection sequence is reversed. By so doing, the size and the position of the defect can be measured accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an ultrasound microscope, and particularly to a transmission-type ultrasound microscope that obtains an observation image using ultrasound transmitted through a sample.

[Background of the invention]

Ultrasonic microscopes of various configurations have been proposed in the past, but these can be broadly divided into reflection types, which take images using ultrasound waves reflected from a sample, and transmission types, which take images using ultrasound waves transmitted through the sample.

There is a type. Examples of the transmission type include Japanese Utility Model Application No. 54-92794 and Japanese Patent Application Publication No. 56-51659. This transmission type ultrasound microscope will be explained with reference to FIG.

In the figure, 1 is a planar acoustic lens that transmits ultrasonic waves, and 2 is a spherical acoustic lens that receives ultrasonic waves. The sonic lenses 1 and 2 are made of a material made of cylindrical fused silica, etc., which has one surface optically polished, and a piezoelectric thin film (for example, made of 6ZnO, etc.) sandwiched between upper and lower electrodes 3 on that surface.
4 is attached, and the other end is an optically polished flat surface in the case of the planar acoustic lens 1, and a hemispherical hole of a concave body with an aperture of about 01 tm -1,0 w x φ in the case of the spherical acoustic lens 2. ing. 6 is the plane acoustic lens l
and the spherical acoustic lens 2, and the space between the sample 6 and the plane acoustic lens 1 or the spherical acoustic lens 2 is filled with a medium (for example, water) 5 that is a sound wave propagation medium. . Reference numeral 7 denotes an oscillator that generates a high frequency current, and the oscillator 7 is connected to the electrode 3 of the planar acoustic lens 1 so as to be able to apply the high frequency current. Reference numeral 8 is connected to the electrode 3 of the spherical acoustic lens 2, and the spherical acoustic lens 2 receives the ultrasonic wave that has passed through the sample 6, converts it into an electric signal with the piezoelectric thin film 4, and receives the electric signal and also performs diode detection. It is a receiver for Reference numeral 9 denotes an echo processing section connected to the receiver 8 and converting the electrical signal into an A/D converter. Reference numeral 11 controls the scanning of the sample 6 in the X-Y direction, and also controls the scanning of the sample 6 of the plane acoustic lens l and the spherical acoustic lens 2.
This is a scanning control device that controls movement in two directions. Reference numeral 10 denotes a digital image memory that synchronizes the scanning information from the scanning control device 11 and the signal from the echo processing section 9 and stores them as image data.

A cathode ray tube (hereinafter simply referred to as CRT) displays image data stored in the digital image memory O.

In such a configuration, if the ultrasonic transmitting side is a plane acoustic lens L as described in 1.
Since the ultrasonic wave is applied to the entire surface and has no focal point, the transmitted power of the ultrasonic wave is relatively small compared to when a spherical acoustic wave lens is used. However, regarding the transmitted ultrasound,
Since no convergence is performed, the resolution is ``wavelength λ.'' On the other hand, when a spherical acoustic lens is used on the ultrasonic transmitting side to transmit a sample with a certain thickness, the transmission output is thick (although the medium In order to reduce the reflection between
D: lens aperture diameter) becomes thicker, and accordingly, the resolution (Δγ=F·λ) becomes thicker by several times the wavelength λ, as shown in the above equation.

Therefore, there is a drawback that actual dimensions cannot be measured from the image created by the obtained image data.

That is, as described above, the CRT 1
If the actual dimensions cannot be measured from the image displayed in 2, it is difficult to understand the size and position of internal cavities or defects in the sample, and it is difficult to align them when observing the same area at different magnifications. However, there were disadvantages such as making the work complicated.

[Purpose of the invention]

It is an object of the present invention to provide a transmission type ultrasound microscope equipped with a planar acoustic lens and a spherical acoustic lens that are arranged opposite to each other with the sample in between, and to be able to accurately grasp changes inside a sample. The object of the present invention is to provide an ultrasonic microscope that can accurately measure dimensions or position R of the sample.

[S Essentials of Invention]

The present invention provides an ultrasonic microscope in which a planar acoustic lens and a spherical acoustic lens are arranged opposite to each other with a sample in between, and an oscillator capable of applying a high-frequency current to the piezoelectric thin film of each acoustic lens;
A receiver that can receive the electric signal received by each sonic lens and converted into an electric signal, and an A/D that outputs the receiver.
a scanning control means for performing relative scanning between the echo processing section for conversion and each sonic lens of the sample; a digital image memory for synchronizing the respective outputs of the echo processing section and the scanning control means and storing image data; It is characterized by comprising a display means for displaying the image data stored in the digital image memory, and a switching means for switching the connection between the planar sonic lens and the spherical sonic lens, the transmitter, and the receiver. .

[Embodiments of the invention]

Hereinafter, one embodiment of an ultrasonic microscope according to the present invention will be described with reference to FIG. In the figure, the same reference numerals as in the conventional example indicate the same members. This embodiment differs from the conventional example in that it includes a changeover switch 20 a that allows the transmitter 7 to be connected to the plane acoustic lens or the spherical acoustic lens 2 as required.

20c, and the receiver 8 is connected to the plane acoustic lens l.
Alternatively, a selector switch 2 can receive any received ultrasonic conversion electrical signal from the spherical acoustic lens 2 as required.
0b and 20d are the digit points.

In such a configuration, when searching for internal cavities or defects in the sample 6, the switching elements 20a and 20c are switched so that the spherical acoustic wave lens 2, which has a large ultrasonic wave sending and receiving force, is on the transmitting side. The spherical acoustic wave lens 2 and the transmitter 7 are connected, and the changeover switches 20b, 20. d to connect the plane acoustic lens 1 and receiver 8. By connecting in this manner, cavities or defects inside the sample 6 can be reliably searched. When determining the size or positional relationship of a cavity or defect inside the sample 6 found by the imaging operation, the changeover switch 20a is set so that the planar acoustic lens 1 is on the transmitting side, contrary to the connection state. 2
0c to connect the planar acoustic lens l and the transmitter 7, and switch the changeover switches 20b and 20d to connect the spherical acoustic lens 2 and receiver 8 so that the spherical acoustic lens 2 is on the receiving side. By connecting in this way, the transmission output of the ultrasonic wave is small. With this configuration, it is possible to easily identify a cavity or defect inside the sample 6, and also to determine the size of the cavity or defect. Or positional relationships can be measured accurately.

〔Effect of the invention〕

As explained above, according to the present invention, changes inside a sample can be accurately grasped, and dimensions or positions of the sample can be accurately measured.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an ultrasound microscope according to the present invention, and FIG. 2 is a block diagram showing a conventional ultrasound microscope. l... Planar acoustic lens, 2... Spherical acoustic lens, 3... Upper and lower electrodes, 4... Piezoelectric thin film, 5... Medium, 6... Sample, 7.
...Transmitter, 8...Receiver, 9...Agent Patent attorney Akira Ko Yoko Fusai 2 diagrams

Claims (1)

[Claims] 1. In an ultrasonic microscope in which a plane acoustic lens and a spherical acoustic lens are arranged facing each other on both sides of a sample, a transmitter capable of applying a high frequency current to the piezoelectric thin film of each acoustic lens, and an electric signal received by each acoustic lens A receiver that can receive the converted electrical signal, and an A/
an echo processing unit that performs D conversion; a scan control unit that performs relative scanning between the sample and each of the sonic lenses; and a digital image memory that synchronizes each output of the echo processing unit and the scan control unit and stores image data. , an ultrasonic microscope comprising display means for displaying image data stored in the digital image memory, and switching means for switching connections between the planar acoustic lens and the spherical acoustic lens, the transmitter, and the receiver. .