JPS59188551A - Ultrasonic microscope - Google Patents

Abstract

PURPOSE:To impress voltages to an upper and a lower electrode securely from the outside of a case by providing a terminal part which has the outer circumferential part made of insulating material and the center part made of conductive material, a ring made of conductive material provided to the circumference of a sound wave propagation medium, etc. CONSTITUTION:An ultrasonic microscope has the terminal part which has the outer circumference made of the insulator 18 and the conductive material 20 fitted only in the center part while a bellows 19 is fitted to the conductive material 20, and this terminal part is inserted into the case 16. The sound wave propagation medium is provided with a spherical lens (sound wave lens); its outer circumference is conductive and has the metallic ring 19 with large rigidity pressed in and the end surface is fixed in level with the top surface of the spherical lens 1. Consequently, voltages are impressed to the upper and lower electrodes securely from the outside of the case to improve the reliability of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an ultrasonic microscope, and particularly to the structure of a piezoelectric thin film portion of an ultrasonic microscope.

[Background of the invention]

In recent years, it has become possible to generate and detect ultra-high frequency sound waves up to IGH2, making it possible to achieve sound wavelengths of approximately 1 μm underwater, and as a result, it has become possible to obtain high-resolution sonic imaging devices. became. That is, a concave lens is used to create a focused sound wave beam, achieving a high resolution of 1 μm. By inserting a sample into this beam and detecting all of the reflected ultrasonic waves from the sample, the elastic properties of minute regions of the sample are elucidated. In addition, the sample can be mechanically
By displaying the intensity of this signal as a brightness signal on a CRT display while scanning in different dimensions, it is possible to enlarge and observe the fine structure of the sample.

FIG. 1 is a diagram showing the main parts of a conventional ultrasound microscope.

The focusing, transmission and reception of ultrasonic waves is performed by a spherical lens 1, whose structure is made by optically polishing one side of a material made of cylindrical fused silica, etc., and piezoelectric thin film (ZnO) 2 is placed on top and bottom of each electrode. 3 to make a sandwich structure. A pulse 5 generated from a pulse oscillator 4 is applied to this piezoelectric thin film 2 to generate an ultrasonic wave 6. In addition, spherical lens 1
A concave hemispherical hole with a diameter of about 0.1 ranφ to 1.0 mmφ is formed at the other end, and a hole for propagating the ultrasonic waves 6 to the sample 7 is provided between the hemispherical hole and the sample 7. Medium (
For example, water) 8 is satisfied. The ultrasonic waves 6 generated by the piezoelectric thin film 2 propagate in the cylinder as plane waves. When this plane wave reaches the hemispherical hole, quartz (sound velocity 6 ooo)
A refraction effect occurs due to the difference in sound speed between water (sound speed: 1500 m/s) and water (sound speed: 1500 m/s), and focused ultrasonic waves 6 can be irradiated onto the surface of the sample 7. Conversely, the ultrasonic wave reflected from the sample 7 is collected and phased by the spherical lens 1, becomes a plane wave, and reaches the piezoelectric thin film 2, where it is converted into a high frequency (F) signal 9.
is converted to This high frequency signal 9 is received by a receiver 10, where it is diode-detected and converted into a video signal 11.
This becomes an input signal for the CRT display 12.

In the apparatus configured in this way, when the sample 7 is scanned two-dimensionally within the X-Y plane by the sample drive power source 13,
The intensity of reflection from the sample surface as the sample 7 is scanned is displayed two-dimensionally on the CRT display surface 12.

In general, some ultrasound waves are reflected by the surface of an object, but a significant portion of the ultrasound waves enters the object, regardless of whether the object is optically transparent or not. ,
It returns as an echo reflecting differences in viscosity, defects, etc. The ultrasonic microscope utilizes this property to detect the internal aspects of the sample 7.

Next, the piezoelectric thin film portion of the ultrasonic microscope will be explained in detail with reference to FIG. FIG. 2(a) is a longitudinal section of a piezoelectric thin film portion of the prior art, and FIG. 2(b) is a plan view of FIG. 2(a) viewed from the direction of the arrow.

A lead wire 14 is attached to a lower electrode 3' formed on the spherical lens 1 and connected to a case 16. Furthermore, this case 16 is grounded. A piezoelectric thin film (ZnO) 2 is sputtered to a predetermined thickness on the upper surface of this lower electrode 3', and an upper electrode 3'' is further deposited on the upper surface.The outer periphery is made of an insulating material 18, and the center The terminal part where the conductive material 20 is arranged only in the case 16
The conductive material 20 of the terminal part and the upper electrode 3"
and is connected by a lead wire 15.

This lead wire 15 and the lead wire 14 provided on the lower electrode
When a pulse voltage is applied between them, the piezoelectric thin film 2 sandwiched between them generates ultrasonic waves and functions as an ultrasonic microscope.

However, in the conventional structure described above, the lead wires 14 are connected to the lower electrode 3' and the upper electrode 3'', respectively.
．． 15 is essential, but the lead wires 14.15 are attached to the spherical lens 1° case 16. Since the lead wire 14 is attached to the closed space formed by the
．． 15 is very difficult to securely attach, and the device has the drawback of lacking reliability.

[Purpose of the invention]

SUMMARY OF THE INVENTION In order to solve such problems, an object of the present invention is to provide an ultrasonic microscope that can reliably apply voltage from outside the case to upper and lower electrodes formed inside the case.

[Summary of the invention]

In order to achieve the above object, the ultrasonic microscope of the present invention includes a piezoelectric thin film sandwiched between a lower electrode and an upper electrode, formed on a sonic lens; In a piezoelectric thin film part of an ultrasonic microscope having a structure in which a terminal part formed of a conductive material and a case made of a conductive material are assembled, a ring made of a conductive material is placed around the sonic lens, and a ring made of a conductive material is placed at the center of the terminal part. A pulse voltage can be applied between the lower electrode and the upper electrode by providing bellows between the lower electrode and the upper electrode, and forming the lower electrode so as to be connected to the ring. It is characterized by

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a diagram for explaining a piezoelectric thin film section according to an embodiment of the present invention.

The outer periphery of the spherical lens 1 processed into a predetermined shape is marked with
As shown in a), a conductive and highly rigid ring 17 made of metal, for example, is press-fitted, and its end surface is shaped like the spherical lens 1.
It is fixed so that it is flush with the top surface of. When the lower electrode 3' is deposited on the entire upper surface of the spherical lens 1 in this state,
As shown in FIG. 3(b), the material of the lower electrode 3' is also deposited on the upper surface of the ring 17, and the two are securely connected. Further, on this upper surface, a piezoelectric thin film (ZnO) 2 is formed by sputtering to a predetermined thickness only within the diameter dl. The diameter dl of the piezoelectric thin film (ZnO) 2 is made larger than the diameter of the hemispherical hole of the spherical lens 1 for propagating sound waves.

On the piezoelectric thin film (ZnO) 2, there is an upper electrode 3'' with a diameter d.
It is deposited with dimensions of 2. The diameter d2 of the upper electrode 3'' is made equal to the diameter of the hemispherical hole for sound wave propagation so that the sound wave is transmitted only to the hemispherical hole for sound wave propagation.

FIG. 4 is a diagram showing an embodiment of the present invention.

The piezoelectric thin film part shown in FIG. 3(C) is assembled into the case 16, and when it is assembled,
7 protects the lower electrode 3', which has low rigidity, so that the lower electrode 3' is reliably connected to the case 16. Since the case 16 is made of metal and grounded, when the piezoelectric thin film portion is assembled in the case 16, the lower electrode 3', the ring 17, and the case 16 are electrically connected, and the lower electrode 3' can be easily grounded. Furthermore, the step of vapor depositing the lower electrode 3' mentioned above is an essential step in the prior art, and in this embodiment, the lower electrode 3' can be reliably grounded simply by expanding the vapor deposition range. It can also reduce man-hours.

The outer periphery is made of an insulator 18, a conductive material 20 is fitted only in the center, and a terminal portion with a bellows 19 attached to the conductive material 20 is inserted into the case 16. In this embodiment, Bakelite was used as the insulator 18 and stainless steel was used as the conductive material 20. The tip of the bellows 19 is in contact with the upper electrode 3''. This contact pressure can be set arbitrarily.
0 can be electrically connected reliably.

Furthermore, the work of assembling the terminal part into the case 16 is easy, and this simple work makes it possible to realize a configuration in which a pulse voltage can be applied to the upper electrode 3''. (see FIG. 2(a)) can be omitted.

In the piezoelectric thin film portion having such a structure, when a high voltage pulse is applied between the conductive material 20 and the case 16, the piezoelectric thin film (
ZnO)2 can perform thickness vibration favorably.

〔Effect of the invention〕

As described above, according to the present invention, voltage can be reliably applied from outside the case to the upper and lower electrodes formed inside the case, and the reliability of the device can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an outline of the configuration of an ultrasound microscope, FIG. 2 is a diagram showing a piezoelectric thin film section of a conventional ultrasound microscope, and FIG. 3 is a diagram showing a piezoelectric thin film section according to an embodiment of the present invention. FIG. 4 is a diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Spherical lens, 2... Piezoelectric thin film, 3'... Lower electrode, 3''... Upper electrode, 16... Case, 17
... Ring, 18 ... Insulating material, 19 ... Bellows, 2o ... Conductive material. Figure 1 ('$2 Figure (ku) Figure 3 tθ)

Claims (1)

[Claims] (2) A piezoelectric body on which an upper electrode and a lower electrode are formed is provided at one end, and a sound wave propagation medium is provided at the other end with a sound wave lens having a predetermined focal point, and a An ultrasonic microscope that images the sample using a disturbance sound wave emitted from the sample, consisting of a terminal portion whose outer periphery is made of an insulating material and whose center portion is made of a conductive material, and a conductive material provided around the sound wave propagation medium. An ultrasonic microscope comprising a ring and a bellows provided between the conductive material and an upper electrode, the lower electrode being connected to the ring.