JPS6347652A - Sonic sensor for ultrasonic microscope - Google Patents

Abstract

PURPOSE:To reduce a multiple reflection sonic wave, by forming a notch part to a propagation route. CONSTITUTION:The ultrasonic wave transmitted from a piezoelectric element 2 straightly advances through a sensor main body 1 as shown by a dotted line to reach a lens 3 and converged to be transmitted toward an observation material. A part of the ultrasonic wave reaching the lens 3 is reflected by each part of the lens 3 to propagate to each part of the sensor main body 1. Notch parts 4, 5, 6, 7 are provided to the intermediate part of the main body 1 so that the arrangement positions in the longitudinal direction of the main body 1 are shifted and the arrangement angles thereof are shifted even in the circumferential direction thereof. Whereupon, the propagation route of the ultrasonic wave is blocked as shown by a solid line arrow and the reflection thereof is repeated in the main body 1 and, finally, a propagation distance becomes long to allow the ultrasonic wave to extinct. by forming the notch parts, the incident of a multiple reflection sonic wave to the piezoelectric element can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a sonic sensor for an ultrasonic microscope, and particularly to a sonic sensor for an ultrasonic microscope that is suitable for having a lens portion.

[Conventional technology]

Conventionally, in an ultrasonic microscope, an ultrasonic wave emitted from a piezoelectric element of a sonic sensor is reflected by a lens section located at an opposite position, and multiple reflected acoustic waves that are further reflected from the side of the sonic sensor are reflected from an observation sample. Since the reflected ultrasonic waves overlap each other and are received by the piezoelectric element, there is a problem in that the multiple reflected ultrasonic waves become noise and a clear observation image cannot be obtained.

Therefore, as a countermeasure against these noises, it is known to apply a sound absorbing material to the outer periphery of the sonic sensor or to make the outer periphery rough so as to easily absorb sound. (Unexamined Japanese Patent Publication No. 58-
(No. 96248, Japanese Utility Model Publication No. 58-31200) [Problems to be Solved by the Invention] However, in the configurations for reducing the multiple reflected sound waves as described above, all of the configurations that reduce the multiple reflected sound waves directly absorb the multiple reflected sound waves. Rather, the multiple reflected sound waves were received by the piezoelectric element, and particularly when the reflected sound waves from the observation sample were at a low level, the noise affected the piezoelectric element, making it impossible to obtain a good image.

An object of the present invention is to provide a sonic sensor for an ultrasonic microscope having a structure in which the multiple reflected sound waves do not enter a piezoelectric element.

[Means for solving problems]

The above purpose is to leave only the ultrasonic propagation path necessary for observation of the sonic sensor and cut the other parts into the propagation path so that the propagation path of the multiple reflected sound waves of the sonic sensor is not configured. Creation of the cutout is accomplished by removing the acoustic wave propagating material.

[For production]

In an ultrasonic sensor, an ultrasonic wave emitted from a piezoelectric element propagates within the main body of the ultrasonic sensor, that is, a sound wave propagating substance, and reaches a lens portion. The ultrasonic waves are focused by the lens section and irradiated onto the observation sample, and the reflected ultrasonic waves from the observation sample are received by the piezoelectric element as plane waves at the lens section.

However, some of the ultrasonic waves emitted from the piezoelectric element are reflected by the lens portion, and are further reflected multiple times within the sound wave propagation material, and then enter the piezoelectric element.

Therefore, as mentioned above, by removing the sound wave propagating material from a portion of the sound wave propagating material other than the necessary propagation path of the ultrasonic wave, that is, by providing a notch, the ultrasonic wave is reflected by the lens part and the sound wave propagates. Multiple reflected sound waves that are multiple reflected within a substance and incident on the piezoelectric element are blocked. That is, by providing the notch, the propagation path of the multiple reflected sound waves is blocked, so the multiple reflected sound waves incident on the piezoelectric element are significantly reduced, and the influence of the multiple reflected sound waves, that is, noise can be prevented. .

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. 1 is a sensor body made of a sound wave propagation material, and 2 is a piezoelectric element installed on a flat surface of one end of the sensor body 1. Reference numeral 3 denotes a lens formed at the apex position of a conical portion at the other end of the sensor body l. Note that the piezoelectric element 2 and the lens 3 are installed in corresponding positions. Reference numerals 4, 5, and 6.7 designate notches provided in the intermediate portion of the sensor main body 1 at different installation positions in the longitudinal direction and at different installation angles in the circumferential direction. Note that the depth of the notches 4 to 7 is such that it does not reach the path through which ultrasonic waves propagate from the piezoelectric element 2 to the lens 3. Further, the installation angles of the notches 4 to 7 in the circumferential direction are all shifted by 90 degrees in the first embodiment.

In such a configuration, as shown in FIG. 2, the ultrasonic waves emitted from the piezoelectric element 2 propagate through the sensor main body IP'3 as shown by the dotted line in the figure, go straight, and reach the lens 3. The ultrasonic waves propagated in this manner are focused by the lens 3 and transmitted toward the observation sample. On the other hand, the lens 3
A portion of the ultrasonic waves that have reached the lens 3 are reflected by each part of the lens 3 and propagate as reflected sound waves to various parts of the lens body 1 as indicated by dotted line arrows in the figure. Of these reflected sound waves, the arrival time of those that directly reach the piezoelectric element 2 can be predicted in advance based on their propagation speed and the length l of the sensor body l, so they can be removed by applying a gate in the signal processing system and are harmful. It's not noise. On the other hand, among the reflected sound waves, the so-called multiple reflected sound waves that are multiple-reflected from the surrounding surfaces of the sensor body l enter the piezoelectric element 2 at the same time as the reflected sound waves from the observation sample necessary for observation, so they are considered harmful noise. Become. However, the propagation path of the multiple reflected sound waves is blocked by the notches 4 and 7, as shown by the solid line arrows in the figure, and is reflected at these parts. And the sensor itself! The light will be reflected repeatedly within the body, and eventually the propagation distance will increase and it will disappear. Incidentally, the propagation path of the multiple reflected sound waves shown in FIG. 2 is shown as an example for convenience of explanation, and if FIG. 2 is viewed geometrically, the path to reach the piezoelectric element 2 can be easily found. The above route will be further explained with reference to FIG.

In FIG. 3, the notches 4 to 7 are formed as shown by hatching, and the multiple reflected waves are reflected from the sensor body 1.
Since the cutouts 4 to 4 are located opposite each other,
It is considered that the signal propagates through a gap of 7, that is, a portion having a width of hth2+h3+h4. In addition, the h1 to h
The dimension of 4 is determined by the diameter of the lens 3, but it is approximately 1 of the diameter of the sensor body l. Therefore, hl+h2+b3+h4=D15
Since the total circumference of the sensor body l is πD, the ratio of both is 1/X5 in 14π. That is, when the cutouts 4 to 7 are provided, the number of multiple reflected sound waves reaching the piezoelectric element 2 is 1/15 of the total.

According to such a configuration, the multiple reflected sound waves that are reflected within the sensor body 1 and reach the piezoelectric element 2 can be reduced to about 1/15 of the conventional value. If the amount of noise can be reduced to this extent, the amount of noise will not cause any practical problems. Therefore, the amount of noise that is received by the piezoelectric element 2 at the same time as the reflected sound waves from the observation sample can be significantly reduced, and a clear observation image can be obtained.

By the way, if the reflected sound waves from the observation sample are extremely weak, even the above-described configuration is expected to be insufficient. However, for convenience of explanation, the embodiments described above have the notches 4 to 7.
Needless to say, if the number of installed devices is increased, the amount of noise can be further reduced.

Therefore, the present invention is not limited to the above embodiments.

In addition, in the above embodiment, by providing the notch in the sensor body as described above, the strength of the sensor body may be reduced and it may be easily damaged. This problem can be solved by filling the material.

〔Effect of the invention〕

As described above, according to the present invention, by providing a notch in the sensor body, it is possible to significantly reduce the incidence of multiple reflected sound waves, that is, noise, on the piezoelectric element, and to perform good observation.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the sonic sensor according to the present invention, FIG. 2 is a sectional view corresponding to the a-a position in FIG. 3, and FIG. 3 is a plan view of the sonic sensor shown in FIG. 1. Figure 4 is the third
It is a sectional view corresponding to the bb section position in the figure. 1...Sensor body, 2...Piezoelectric element,
3...Sini-Ol prisoner 93 figures 2 figures 4 figures

Claims (1)

[Claims] 1. Made of sound wave propagation material, with a piezoelectric element installed at one end,
A sonic sensor for an ultrasonic microscope having a lens at the other end, characterized in that a notch is formed at a position equivalent to the propagation path of the ultrasonic waves reflected by the lens to the piezoelectric element. .