JPS6395349A - Scanner of ultrasonic spectroscope - Google Patents

Abstract

PURPOSE:To enable highly accurate fast scanning, by employing a bimorph diaphragm comprising a ceramic piezoelectric body as actuator. CONSTITUTION:A vibrator is made up of a bimorph diaphragm 10 comprising a ceramic piezoelectric body, a mounting base 12 for fixing both ends of the diaphragm 10 and an AC power source 16 connected to electrodes provided on both sides of the diaphragm 10, which is connected to a transducer with a support arm 14. Here, as displacement of a thickness mode of the diaphragm 10 is directly proportional to an applied voltage, an actuator is obtained which facilitates the control of the displacement depending on voltage. Then, when a voltage is applied to the diaphragm 10, the diaphragm 10 vibrates in the direction of the arrow, which enables horizontal reciprocation of a transducer unit fixed at the other end of the arm 14, by connecting one end of the arm 14 to the diaphragm 10. Thus, this enables highly accurate fast scanning.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an ultrasound microscope, particularly to a scanning device for a mechanical scanning ultrasound microscope.

[Prior Art] Ultrasonic microscopes transmit and receive ultrasonic beams to and from a sample using a transducer unit, and obtain information on minute areas of the sample by reflecting or transmitting the beams. Mechanical scanning is generally used as a scanning method. It is true.

The mechanical scan is applied to either the sample or the transducer, and a vibrator is connected to the sample stage or the transducer unit, and xy two-dimensional scanning is performed by various combinations of multiple scans to achieve the desired magnification. I'm getting a statue.

In particular, a moving coil actuator is suitable for the exciter of the scanning device when high-speed scanning is required.

An example of the configuration of a conventional scanning device will be explained with reference to FIG. FIG. 3 shows an X-direction scanning device consisting of a transducer unit 36, a vibrator 38, and a support arm 14 that connects the two, and a pulse motor stage that scans a sample stage 24 on which a sample 32 is placed in the Y direction. Consists of 22.

The transducer unit 36 is composed of a piezoelectric transducer 26 including an ultrasonic transducer, and an acoustic lens 28 whose upper end is flat and whose lower end is concave for focusing an ultrasonic beam. electrically connected to.

The ultrasonic waves transmitted from the piezoelectric transducer 26 are focused by the acoustic lens 28 and transmitted to the sample 32 by the transmission medium 30.
The transducer unit 36 receives the reflected wave due to its acoustic characteristics, thereby obtaining information on the minute area.

FIG. 4 shows a configuration example of a conventional moving coil actuator, in which a hollow moving coil 52 is supported in a permanent magnet 50 forming a magnetic circuit, and the moving coil 52 has a transducer unit at the other end. 36 is fixed to one end of the support arm 14.

When a current is passed through the moving coil 52, this current cuts the magnetic flux generated from the permanent magnet 50, so the moving coil 52 reciprocates in the direction of the arrow in the figure, and is connected to the moving coil 52. The transducer unit 36 can be horizontally reciprocated.

Therefore, the transducer unit 36 is scanned at high speed in the X direction by the moving coil actuator, and the sample stage 24 is scanned at low speed in the y direction by the pulse motor stage 22, thereby making it possible to obtain an enlarged image of a minute region of the sample 32. .

[Problems to be Solved by the Invention] However, in conventional scanning devices, the ultrasonic beam is scanned by mechanical vibrations caused by a moving coil, so there is a problem in that it is difficult to perform highly accurate scanning that requires minute vibrations. be.

In other words, since the amplitude of the moving coil is determined by the magnetic flux from the permanent magnet and the current flowing through the moving coil, the movement of the transducer unit can be controlled with an accuracy of a few tenths to a few hundredths of a micron. It is simply impossible to do so.

Therefore, with conventional scanning devices, it is impossible to increase the scanning density and obtain information in finer areas.

Furthermore, since the exciter of the conventional scanning device is composed of a permanent magnet and a moving coil, the exciter is large and heavy, making it difficult to make the scanning device smaller and lighter.

In order to solve the above-mentioned problems, an object of the present invention is to provide a small and lightweight scanning device for an ultrasound microscope that is capable of highly accurate scanning.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a transducer unit of an ultrasonic microscope or an exciter of a scanning device for moving a sample stage, with both ends made of a ceramic piezoelectric material. The vibration exciter includes a fixed bimorph diaphragm.

[Example] Hereinafter, a preferred example of the present invention will be described based on FIGS. 1 to 3.

FIG. 1 is a configuration example of a vibrator according to the present invention, and FIG. 2 is an explanatory diagram of a bimorph diaphragm. The same members as those in the conventional example are given the same reference numerals, and their explanations will be omitted.

In FIG. 1, a vibrator 38 according to the present invention includes a bimorph diaphragm 10, a mounting base 12 for fixing both ends of the bimorph diaphragm 10, and an AC power supply connected to electrodes provided on both sides of the bimorph diaphragm 10. 16, and the bimorph diaphragm 10 is connected to the transducer unit 36 by the support arm 14.

FIG. 2 shows an example of the structure of the bimorph diaphragm 10. In this embodiment, cords 18 (piezoelectric elements) made of ceramic piezoelectric material are provided on both sides of the elastic reinforcing plate 20 so that the polar directions are different. Both ends of the plate 10 are fixed, and each piezoelectric element 18 is provided with an electrode.

When a voltage is applied to the bimorph diaphragm 10 as shown in Figure 2, an electrostatic force acts between the positive and negative charges inside the ceramic and the external charges in proportion to the applied voltage, causing the ceramic to expand and contract. When one piezoelectric element 18 expands, the other piezoelectric element 18 contracts and bends in the vertical direction, causing thickness mode displacement in the bimorph diaphragm 10 as shown by the broken line.

Since the amount of displacement in the thickness mode of the bimorph diaphragm 10 at this time is directly proportional to the applied voltage, an actuator whose displacement amount can be easily controlled by voltage can be obtained.

When the bimorph diaphragm 10 having the configuration shown in FIG. 2 is arranged as shown in FIG. 1 and a voltage is applied, the bimorph diaphragm 10 vibrates in the direction of the arrow, causing one end of the support arm 14 to Transducer unit 3 fixed to the other end of support arm 14 by connecting
6, horizontal reciprocation as shown by the arrow in FIG. 3 is possible.

In the embodiment, the vibrator 38 and the transducer unit 36 are connected to move the transducer unit 36, but the vibrator 38 and the sample stage 24 are connected and the sample stage 24 is moved. A similar effect can be obtained by using a scanning device that moves.

A characteristic feature of the present invention is that by using an exciter including a bimorph diaphragm made of a ceramic piezoelectric material as an actuator of a scanning device, highly accurate high-speed scanning of a transducer unit or a sample stage can be easily performed. That's true.

That is, in the present invention, since the bimorph diaphragm is excited by applying a voltage, the amplitude can be easily controlled and minute vibrations with a small amount of displacement can be obtained.

Therefore, according to the present invention, it is possible to move the transducer unit or the sample stage with high precision, and a scanning device with high scanning density is possible.

Furthermore, a feature of the present invention is that by using a bimorph diaphragm as an actuator, a lightweight and compact scanning device can be obtained.

That is, unlike the conventional scanning device, a magnetic field is not required, so a magnet is unnecessary, and since it is not dependent on mechanical vibration, a lightweight, compact, durable, and low power consumption scanning device can be achieved.

In addition, in the embodiment, the bimorph diaphragm 10 has a rectangular shape, but it is also possible to use a circular plate with its periphery fixed as an exciting exciter, and the element material of the bimorph diaphragm 10 may be made of other materials. It is also possible to use a piezoelectric material.

As described above, according to the present invention, it is possible to obtain a scanning device that is capable of highly accurate high-speed scanning, is lightweight, compact, and has low power consumption.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a lightweight and compact scanning device capable of high-accuracy, high-density, and high-speed scanning.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a vibrator according to the present invention, Fig. 2 is an explanatory diagram of a bimorph diaphragm, Fig. 3 is a configuration diagram of a scanning device, and Fig. 4 is an explanatory diagram of a conventional vibrator. . 10... Bimorph diaphragm 12... Mounting base 14... Support arm 18... Piezoelectric element 20... Elastic reinforcing plate 24... Sample stage 32... Sample 36... Transducer Unit 38...
Vibrator.

Claims (2)

[Claims] (1) In a scanning device that moves the transducer unit or sample stage of an ultrasound microscope that magnifies and displays minute areas by transmitting and receiving ultrasonic waves to and from the sample, an exciter that moves the transducer unit or sample stage back and forth, and a transducer unit or sample a support arm that connects the stand and the vibrator, the vibrator includes a bimorph diaphragm connected to one end of the support arm, and a mounting base that fixes both ends of the bimorph diaphragm; A scanning device for an ultrasound microscope, characterized in that it enables high-speed scanning of a transducer unit or a sample stage by exciting a plate. (2) A scanning device for an ultrasonic microscope according to claim (1), wherein the bimorph diaphragm is made of a ceramic piezoelectric material.