JPS6295460A - Acoustic wave probe - Google Patents

Abstract

PURPOSE:To eliminate trouble due to the reflection of an ultrasonic wave in an acoustic lens and to prevent the ultrasonic wave from attenuating in the acoustic wave lens by forming the whole acoustic lens body conically. CONSTITUTION:The acoustic lens 1 is composed of an acoustic wave propagation body formed conically on the whole. An ultrasonic wave 7 which is oscillated by a piezoelectric element 2 into the lens 1 and reaches its spherical surface part 8 is reflected by a sample 9 and transmitted as a video signal 13 to a display body 14. An ultrasonic wave 7 which reaches a position off the spherical surface part 8 is reflected by the curved surface part of the acoustic lens 1 to the peripheral part of the plane part. Consequently, the possibility of the reflected ultrasonic wave 7 reaches the piezoelectric element 2 is decreased greatly and the adverse influence of the reflected ultrasonic wave 7 is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a sonic probe, and particularly to a sonic probe jar used in an ultrasound microscope.

[Background of the invention]

The sonic probes, or sonic lenses, used in ultrasound microscopes often have a flat tip. The ultrasonic waves leak into the sound propagation medium, such as water, and are radiated, so that the signal of the focused ultrasonic beam cannot be used effectively, resulting in a deterioration of the effective ultrasonic wave-to-noise ratio (hereinafter simply referred to as S/N). Therefore, in order to prevent this 8/N deterioration, it has been devised to attach a sound absorbing material to the edge of the spherical part of the acoustic lens (for example, Japanese Utility Model Publication No. 58-31200).
However, in reality, in the case of a sound wave lens with a high frequency and a short focal length, if a sound absorbing material is installed near the spherical part of the tip to attenuate the leaked ultrasonic waves, the sound absorbing material will be removed during observation. There was a risk of contact with the sample, and there were problems such as inconvenience in setting up a working distance. Furthermore, since reflection of ultrasonic waves always occurs within the sonic lens, it is difficult to completely eliminate unnecessary radiation. Furthermore, there is a problem in that attenuation of ultrasonic waves propagating inside the acoustic lens increases significantly when the frequency is high in the vicinity of the GHz unit.

[Purpose of the invention]

The object of the present invention is to prevent problems caused by the reflection of ultrasonic waves within the i-wave lens, and to prevent the attenuation of ultrasonic waves within the sonic lens to create an efficient sonic lens. Our objective is to provide a sonic probe.

[Summary of the invention]

The present invention reduces ultrasonic waves that are reflected within a sonic probe, which is a sonic wave propagating body, so-called a sonic lens, and reaches a piezoelectric element.
Further, in order to prevent ultrasonic waves from attenuating within the sonic lens, the entire sonic lens is formed into a conical shape.

[Embodiments of the invention]

An embodiment according to the present invention will be explained below with reference to FIGS. 1 and 2. In the figure, reference numeral 1 denotes a sonic lens consisting of a sound wave propagating body having a conical shape as a whole, and 2 a piezoelectric filter mounted on the flat surface of the sonic lens 1 sandwiched between an upper electrode 3 and a lower electrode 4. (For example, ZnO, etc.)
It is. Reference numeral 5 denotes a pulse oscillator that generates pulses 6 to be applied to the piezoelectric element 2. The pulse 6 is transmitted through the piezoelectric element 2
, the ultrasonic wave 7 is oscillated from the piezoelectric element 2 into the sonic lens 1 . 8 is an aperture formed at the tip of the sonic lens 1 with a diameter of 0.1 mflu to 8.0 II! I
It is a spherical part with a concave surface of about If. Reference numeral 9 denotes a sample, and a sound wave propagation medium (for example, water) is provided between the sample and the spherical part 8 of the sound wave lens 1.
10 is standing tall. The twist is to generate a high frequency signal (
This is a receiver that receives an RF multiplied signal (hereinafter referred to as an RF signal) 11, performs diode detection, and converts it into a video signal 131. Reference numeral 14 denotes a display device that synchronizes the video signal 13 from the receiver with scanning information from the sample stage driving means 15 for scanning the sample 9, converts it into an image, and displays the image. Note that 16 is the sound wave lens 1
The edge of the spherical portion 8 is formed at an acute angle.

In such a configuration, a pulse signal 6 oscillated from a pulse oscillator 5 is applied to the piezoelectric element 2 to generate an ultrasonic wave 7. The ultrasonic waves 7 are focused and irradiated onto the surface of the sample 9 by the refraction effect that occurs at the spherical portion 8 due to the difference in sound speed between the sound wave propagating body forming the sound wave lens 1 and the sound wave propagating medium 10 .

The ultrasonic wave irradiated in this way is reflected by the sample 9 and collected by the spherical part 8 of the sonic lens 1 with a phase adjustment n.
It becomes a plane wave and reaches the piezoelectric element 2. The ultrasonic wave 7 is converted into an RF signal 11 by the piezoelectric element 2 and sent to the receiver n, and is diode-detected by the receiver and converted to a video signal 13, which is then sent to the display 14 (which is sent to the receiver n). According to this configuration, among the ultrasonic waves 7 emitted from the piezoelectric element 2 inside the sonic lens 1, those that reach the spherical part 8 reach the sample 9 and are reflected to the display 14 as described above. It is transmitted as a video signal 13.

On the other hand, the ultrasonic waves 7 that reach a position outside the spherical surface 8 are reflected by the curved surface of the sonic lens 1 to the peripheral portion of the flat surface. Therefore, the reflected ultrasonic waves 7 rarely reach the piezoelectric element 2, and the adverse effects of the reflected ultrasonic waves 7 can be prevented. In addition, in the case of a conventional sound wave lens in which a conical part is formed at the tip of the cylinder, the light is further reflected by one cylinder part.
In many cases, the ultrasonic waves reflected from the piezoelectric element reach the piezoelectric element, and compared to this structure, the above structure can significantly prevent the adverse effects of the reflected ultrasonic waves.

Further, according to the above configuration, since the distance from the piezoelectric element 2 to the spherical surface portion 8 can be shortened, even ultrasonic waves having a very high frequency on the GHz scale can be prevented from being attenuated within the sonic range 1.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to prevent problems caused by reflection of ultrasonic waves within the sonic lens, and also to prevent attenuation of ultrasonic waves directly within the sonic lens.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an outline of an ultrasound microscope using an embodiment of the sonic probe according to the present invention, and FIG. 2 is a sectional view showing the sonic probe of FIG. 1.

Claims (1)

[Claims] 1. A sonic probe that is placed facing a sample, transmits and receives ultrasonic waves to and from the sample, and performs relative scanning to observe the sample; What is claimed is: 1. A sonic probe characterized in that a spherical surface is formed at the tip of the probe, and a piezoelectric element is provided on the flat surface. 2. The sonic probe according to claim 1, wherein the tip angle of the conical shape is set at an angle such that reflected ultrasound waves from the curved surface do not reach the piezoelectric element.