JPS5819556A - Soundwave probe for ultrasonic microscope - Google Patents

Abstract

PURPOSE:To eliminate need for the readjustment of the focus when the soundwave transmission medium is changed by constructing at least two accoustic lenses each made out of an electricity soundwave conversion member so as to normally share the same focal length and focal point. CONSTITUTION:Four electricity-soundwave conversion members 10a-10d are integrated in symmetry with respect to the center axis to construct a diagonal irradiation type soundwave probe 9. When a high frequency signal is applied to a wave transmitting transducers 15a and 15c and converted into ultrasonic waves. The ultrasonic waves are propagated as plane wave through a soundwave propagation elements 19a and 19c and projected into a soundwave transmission medium 21 through accoustic lenses 20a and 20c for wave transmission at the bottom thereof so as to be focused on the focal point F. Those ultrasonic waves focused on accoustic lenses 20b and 20d are propagated as plane wave through wave receiving elements 19b and 19d, converted into high frequency signals with wave receiving transducers 15b and 15d and transmitted to a signal processing section. The soundwave probe is moved relative to the surface of the sample to scan it and electrical signals are processed to obtain a two- dimensional image of the surface of the sample.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sonic probe that is applied to an ultrasonic microscope and transmits and receives ultrasonic waves.

Ultrasonic microscopes include reflection types and transmission disks, etc. Among the reflection types, there are those that use one sonic probe to send and receive ultrasonic waves to scan the sample, and those that scan the sample using two sonic probes on the surface to be observed of the sample. Some probes are arranged at a predetermined angle and the sample is scanned by receiving ultrasonic waves emitted from one probe with the other probe. An example of a sonic probe used in the 11iv111 ultrasonic microscope with such a configuration is the JP-A-Sho U-J? Visit o
There is one shown in Publication No. As shown in Figure 7, the two sonic probes /&, /b on the transmitting side and the receiving side are tilted at a predetermined angle to each other, and the acoustic waves of the sonic probes /&, /b are measured. Both lenses JIL and Cob have the same focus!・Sound wave probe/JL.

/b is the transmission propagation element Ja, the delivery propagation element Jb, respectively.
,.

At one end, a transducer a for transmitting waves that converts electrical signals into ultrasonic waves, and an F transducer a for transmitting waves that converts vowel waves into electrical signals, are provided at one end, and at the other end, transducers a for transmitting waves that convert electrical signals into ultrasonic waves, respectively, and an F transducer a for transmitting waves that converts vowel waves into electrical signals. A sample t to be observed is placed at the confocal point 1 of the two sonic probes via an ultrasound transmission medium j (for example, a liquid). The operation of a sonic probe with such a configuration is based on 11gII applied to the transmitting transuser a.
The signal is converted into an ultrasonic wave by the transmission trandue 'a, and this ultrasonic wave propagates inside the wave transmission propagation element Ja,
Ultrasonic transmission medium emitted by the transmitting acoustic lens 2a!
is focused on the focal point F via the . focus! The ultrasonic waves reflected by the sample B are collected by the delivery acoustic lens 2b provided so as to share the focal point t.

The sample ≦ is moved relative to the probe by a scanning device (not shown). This ultrasonic wave propagates within the receiving propagation element 3b and reaches the delivery transducer b, where it is converted from the ultrasonic wave to an electrical signal. Ru. By processing this signal, an image of the sample surface can be obtained.

However, with such a sonic probe configuration, the two sonic probes must be placed close to each other at a predetermined angle, and the dimensions of the sonic probes, including the focal length of the acoustic lens, must be limited. In addition, the two acoustic probes must be arranged so as to share an unclear focal position, making the adjustment very cumbersome. In particular, even if the adjustment is made once, if the ultrasound transmission medium between the sonic probe and the sample is replaced with a different type, the focal position will shift and re-adjust due to the difference in sound speed in the ultrasound transmission medium. Needs adjustment. This positioning to the focal position is the same for the sample, making adjustment a matter of course. In addition, since a complicated adjustment mechanism is required to adjust the two sonic probes so that they are confocal with each other, it is not possible to scan the sample by driving the sonic probe when obtaining an image of the sample. Since it is internal, scanning vibration can only be generated on the sample side. For this reason, the sample has the drawback of being limited in size, weight, etc. in order to withstand the vibrations.

In general, another example of a sonic probe used in an ultrasonic microscope is shown in Japanese Patent Application Laid-Open No. 116011/1998. The sonic probe of this specification is shown in FIG. In the figure, the same parts as in FIG. 1 are given the same reference numerals, and descriptions of the similar configurations and operations will be omitted. In the integral transmitting/receiving propagation element 1 in the shape of a buried prism, transducers a and *b for transmitting and transmitting waves are provided so as to form an angle of 900 degrees with respect to each other. @/Similar to the figure, the respective tone scales a and λb formed corresponding to these transducers a and da b have the same focal point! are shared.・
In a sonic probe with such a configuration, the propagation elements on the transmitting side and the receiving side are integrated, so it is relatively easy to move the probe side and scan. Restrictions on size, weight, etc. that can be used are removed. However, in addition to the above-mentioned drawbacks of the conventional example shown in FIG. It has the disadvantage of being ugly.

SUMMARY OF THE INVENTION The object of the present invention is to provide a sonic probe for an ultrasound microscope that is appropriately configured to eliminate the above-mentioned drawbacks and to simplify the position adjustment of a plurality of electro-sonic converting members. The present invention provides at least two electro-acoustic transducers having an electro-acoustic transducer provided at one end of a sound wave propagation element and an acoustic lens formed of a curved surface of the same curvature at the other end, symmetrically about a central axis and Each acoustic lens is integrally coupled to each other via a sound wave separator so that each acoustic lens has the same focal point on the central axis, and with respect to the central axis, one converting member is on the wave transmitting side and the other converting member is on the receiving side. They are characterized in that they can be used independently.

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

FIG. 3 is a perspective view showing the external appearance of an example of the configuration of a sonic probe for an ultrasound microscope according to the present invention. The oblique irradiation type sonic probe has three electrical-sonic converting members la and symmetrical about the central axis.
, 10b, /Do, /σd are integrally formed into a buried cylindrical shape. Each sonic probe toa-toc
l is the electrical-sonic transducer member IO & on the transmitting side about the central axis.
, 106 are provided with receiving-side electro-sonic wave converting members/(Ib, 10ei), respectively.

Figure (6), Φ) and trunk) are the top view, bottom view and s! of the oblique irradiation type acoustic wave probe in Figure 3, respectively. It is a sectional view taken along the line A-m. s (As shown in ~), lower electrodes of gold titanium, aluminum, aluminum, etc. are provided on the upper surfaces of the three electric-sonic transducer members 70a-10a, respectively.
/l, /20. /Jd t 8 and 41113 respectively near the center above these lower electrodes 721-/Jd.
'a A thin film-like piezoelectric material such as zinc oxide in the shape of a circle lJ&
,/Jb.

/10,1361g provided, rough IC contact piezoelectric material /J
Above IL-/Jd are circular upper electrodes 1, 1, 0 and 0, respectively. / reference d is provided. The upper and lower electrodes sandwiching the piezoelectric body each constitute a transducer. That is, transducers /3&, /10 for transmitting waves are placed above the electro-sonic transducers 10&, /Do on the wave sending side, respectively, and transducers /3&, /10 are placed above the electro-sonic transducers 10b, IOa on the receiving side, respectively. Transducer for /! b, /jc1 are formed as %l1II'@Kameki\Fuka conversion part floor~''%%N%%.The three electric-sonic wave converting members 10&-/Da independently without interfering with each other. The sonic separator n is sandwiched like a crop and formed into one piece.The sonic separator n is made of a polymeric material or a material that greatly improves the acoustic properties of the sound wave propagation element of the sonic probe. As shown in (0) and (0), the bottom surfaces of the three electro-sonic transducer members 10a to 10d are equipped with sound wave propagation elements such as 7-ears, respectively. 9b.

/90. /9 (1 appears. These sound wave propagation elements /9
Acoustic lenses 21a are placed at predetermined positions on the bottom of a to /9a, respectively.
xb.

Jo, form xd. The table of these acoustic lenses -a, Jd and the sound wave separator 17 [1ft shape is a spherical surface centered at one point on its central axis. Therefore, these three acoustic lenses M&-:llCl are +7 on its central axis. )
Confocal structure m' with one point as the same focal point and the same focal length as one! -Have.

FIG. 3 is an enlarged sectional view of FIG. 3 (0).

Acoustic lens JJJ on the bottom of sound wave propagation element /9&, /9b
171), when observing with the sonic probes located below the upper electrodes 1* &I#b, respectively in the axial direction, the acoustic lens of the sonic probe and the sample to be observed are Fill the gap with liquid sound wave transmission medium J and observe! I am a child. The distance 1 between the upper surface of the acoustic wave propagation element and the extreme end of the acoustic wave separator on the central axis is, for example, ρ2 where the Fresnel focal length is l. Define it like a wavelength.

The operation of the oblique irradiation type sonic probe having such a configuration will be explained. A high-frequency electric signal is applied to the transducer Ij&, /30 for wave transmission and converted into an ultrasonic wave. This ultrasonic wave propagates as a plane wave in the sound wave propagation elements /9tL and /TS0 for wave transmission, and is ejected into the sound wave transmission medium such as the acoustic lenses for wave transmission, VA, and xa, respectively, and is focused at a focal point F. . Ultrasonic waves are absorbed and scattered and reflected on the sample surface, and others are incident at a critical angle with respect to the normal to the sample surface and are re-radiated in the process of propagating locally on the sample surface. . Among these ultrasonic waves, those collected by the receiving acoustic lens ° propagate as plane waves in the delivery propagation elements /9b and /9a, and are transmitted to the receiving transducers /jb and /j (1) as high-frequency waves. It is converted into an electrical signal and sent to the signal processing section.The sonic probe on the transmitting side and the sonic probe on the receiving side are arranged at right angles to each other, so the sample surface and the sonic probe can be moved relative to each other. A two-dimensional image of the sample surface can be obtained by scanning and processing this electrical signal. If the sound wave transmission medium J filled between each acoustic lens and the sample is replaced with a different one, the sound wave transmission The focal length of an acoustic lens changes depending on the difference in the speed of sound in the medium, but the changed focal position is still confocal for each acoustic lens, and the emission of ultrasonic waves, reflection on the sample surface, There is no change in the collection of reflected waves.

Figure 4 is a diagram for explaining how to use an example of the oblique irradiation type sonic probe shown in Figure 81J.
A sample n is placed under the acoustic wave conversion members 10&, 100 and the electric-sonic wave conversion members 10b, 10 (1) on the delivery side.
, 2s. Display devices M and B display images of the slope based on electrical signals generated from the sound wave transducing members 10b and 2s, respectively. With a device configured like this,
When two-dimensional scanning of the sample B is performed, if the reflection state of the sound wave changes depending on the scanning direction due to the characteristics of the sample, for example, if the sample is a crystal with directionality, the display device 21. If there are clear directions and unfocused directions in the H image, it is known that the sample has directionality.

In addition, in such a case, the electricity-sound wave 1+ on the two delivery sides
By combining the signals of the cross member and displaying it on one display device, a clearer image of the sample surface can be obtained regardless of the orientation of the sample. 2 orthogonal with the same output of the wave side electric-acoustic conversion member
By performing signal processing by superimposing the output signals of the electric-acoustic transducer on the delivery side, which is distributed in two strike directions, it is possible to eliminate changes in one image obtained regardless of the rotation of the sample surface. 1 is a perspective view diagrammatically showing the configuration of an example of a pond of a sonic probe for an ultrasound microscope according to the present invention.

In the embodiments described above, an oblique irradiation type sonic probe that performs two-dimensional scanning is shown, but here, a conventional oblique irradiation type sonic probe that performs one-dimensional scanning is shown. The same parts as those of the oblique, irradiation type acoustic wave probe shown in FIG. In this example, 1
The electro-sonic transducer members 10& on the transmission side and the electro-sonic transducer member 10b on the delivery side are integrally formed via the acoustic wave separator 77'f, and are symmetrical about the central axis.

Although the oblique irradiation type acoustic wave probe according to the present invention has a cylindrical outer shape, the outer shape is not limited to this and may be a prismatic shape.

As is clear from the above description, according to the oblique irradiation type acoustic probe according to the present invention, the acoustic lenses of three or two electro-sonic transducer members always have the same focal length, and Since the structure is configured so that the sound waves are shared, there is no need to adjust the individual sound wave probes so that they have the same focal position during observation, and various sound wave transmission media with different sound velocities can be used interchangeably. However, since each electro-acoustic lens still has a confocal feature, there is no need to adjust the focus again as in the conventional method.In addition, since multiple electro-acoustic transducers are integrated, there is no need to adjust the focus again. By saving the space between each conversion member, the device can be made smaller, and the scanning to obtain the sample image can be performed by moving the sonic probe 1irt, allowing the sample to be scanned over a large distance. , weight etc. 5e
It has the effect of not adding at.

Since the focus of each electric-sonic transducer is the same, the sonic probe can be easily focused on the observation position of the sample to be observed.The sample surface is scanned two-dimensionally. It is possible to determine whether or not the sample has directionality based on the information on the sample surface based on this set of information, and by performing signal processing by combining or superimposing these two sets of transfer signals, it is possible to determine the directionality of the sample compared to one-dimensional scanning. This has the advantage that one stable image can be obtained despite the rotation, making it possible to observe the sample accurately.

[Brief explanation of the drawing]

Figure 1 is a flii diagram showing the configuration of an example of a sonic probe applied to a conventional ultrasound microscope, and Figure 2v4 is a flii diagram showing the configuration of an example of a sonic probe applied to a conventional ultrasound microscope.
Fig. 3 is a perspective view showing the external appearance of an example of the structure of a sonic probe for an ultrasound microscope according to the present invention; (~, Φ) and (0) are the plan @ 1 view, bottom view, and cross section W1 of the sonic probe shown in Fig. 97, respectively, and Fig. 5 is the 1st
114 is a line diagram for explaining the oblique irradiation type sonic probe shown in FIG. It is a perspective view diagrammatically showing the structure of another example of a cetacean. 9... Oblique irradiation - sonic probe, 10&-10a...
Electricity-/21~/2a-・Lower electrode, /1&~11
6-Piezoelectric body, i-tei a~t9a-...upper electrode, /j
5L ~/3ei-? Lance deaster, 17...Sound wave separator, /9&-/9(1...Sound wave propagation element, 275
L-rd...acoustic lens. Patent issuer: Olympus Optical Industry Co., Ltd. Figure 5 Figure 6 Figure 7r? :I

Claims (1)

[Claims] L. An electro-acoustic transducer rte is installed at one end of the sound wave propagation element, and at least λ electro-acoustic transducers, each having an acoustic lens formed of a curved surface with the same curvature formed at the other end, are arranged symmetrically about the central axis and The lenses are integrally coupled to each other via a sound wave separator so that the lenses have the same focal point [-H on the central axis, and one conversion member is on the wave transmission side and the other conversion member is on the reception side with respect to the central axis. A sonic probe for an ultrasonic microscope, characterized in that it can be used independently as a sonic probe.