JPH0136583B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic microscope, and more particularly to improvements in its scanning device.

As a conventional ultrasonic microscope, there is one shown in FIG. 1, for example. A sample 3 is held by a sample holding frame 4 at the focal position of an acoustic lens 2 of an acoustic lens system 1 connected to a transducer that is an ultrasonic transmitting/receiving element. Acoustic lens system 1 is fixed. Scanning of the sample 3 is performed by fixing the acoustic lens system 1 and moving the sample holding frame 4 in the x and y directions. For this purpose, the sample holding frame 4 is connected via an arm 6 to the center of a loudspeaker 7, which is a drive in the x direction. The entire loudspeaker 7 is fixed to its support 8. A rail 9 is provided on the side surface of the support 8 so that the entire support 8 can be moved in the y direction by a y direction drive mechanism comprising a DC motor 10, a micrometer 11, etc. According to such an ultrasound microscope, ultrasonic waves from the transducer are transmitted and received between the sample 3 and the transducer via the acoustic lens 2, while the sample holding frame 4
The sample 3 held by the sample 3 is reciprocated at high speed in the x direction by the loudspeaker 7, and moved at low speed in the y direction by the rotation of the micrometer, thereby performing two-dimensional scanning in the x and y directions. However, in this method of moving the sample by the movement of the sample holding frame, the sample must be large enough and heavy enough to be placed on the sample stage, and the high-speed reciprocating motion of the sample stage also prevents vibration and deformation. It must be something that does not cause
Furthermore, it must be attached to the sample stand so that it can withstand movement of the sample stand.

To solve this problem, there is a method in which the focused ultrasonic transmitting/receiving element side is moved back and forth at high speed.

As shown in FIG. 2, an ultrasonic transmitting/receiving element 21 consisting of a transducer and an acoustic lens is arranged above the sample 20, and connected via a drive shaft 22 to an x-direction drive device 23 consisting of the same mechanism as the loudspeaker. , the ultrasonic transmitting/receiving element 21 is caused to reciprocate at high speed in the x direction. Further, the sample holding table 24 that holds the sample is moved at low speed in the y direction by a not shown y direction moving mechanism (for example, a mechanism using a lead screw, etc.) to perform two-dimensional scanning using ultrasonic waves.

However, with an ultrasound microscope configured like this,
The ultrasonic transmitting/receiving element 21 is arranged so that its tip is located above the lower end of the x-direction drive device 23 when viewed in the horizontal direction, so when the sample area is large, the x-direction drive Since the sample must be placed so as not to come into contact with the device 23, there is a drawback that only the peripheral part of the sample can be observed. In addition, this type of x-direction drive device is large in shape,
Furthermore, since it is heavy, it becomes difficult to design the ultrasonic microscope, and there are also drawbacks in that it places significant restrictions on the configuration of the ultrasonic microscope itself.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and provide an appropriately constructed ultrasonic microscope capable of observing even large samples with a wide area.

The present invention provides an ultrasonic microscope in which a sample holding table that holds a sample is moved in a first direction, and an ultrasonic transmitting/receiving element is reciprocated in a second direction perpendicular to this to observe a sample by two-dimensional scanning. , an excitation means having a holding member that holds the ultrasonic transmitting/receiving element movably in the second direction, and a reciprocating drive mechanism that generates an electromagnetic force that moves the ultrasonic transmitting/receiving element in the second direction. The ultrasonic transmitting/receiving element is arranged so that its tip is located below the lower end of the vibration excitation means when viewed in the horizontal direction. Further, in the holding member, each surface of the pair of leaf springs is arranged parallel to the surface containing the ultrasonic beam, and one end of each leaf spring is connected to the ultrasonic transmitting/receiving element with an end surface that substantially coincides with the direction of the ultrasonic beam. do.

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

FIG. 3 is a perspective view of essential parts showing the configuration of an example of a scanning device for an ultrasound microscope according to the present invention. x, y,
Set the z direction as shown by the arrow. The ultrasonic transmitting/receiving element 26 composed of an acoustic lens and a piezoelectric transducer is attached to the holder 27 with the acoustic lens side partially protruding downward in the z direction. The cable of the piezoelectric transducer is made to extend outside through a hole provided in the upper part of the holder 27. A pair of protrusions 28 and 29 are provided on both sides of the holder 27, and rod-shaped permanent magnets 30 and 31 are fitted into the protrusions, respectively, passing through the interior in the x direction. These permanent magnets 30 and 31 are arranged so that their polarities are opposite. One end of a pair of leaf springs 32 and 33 is fixed to both side surfaces of such a holder 27, and the other end is fixed to support the holder 27. Protrusions 34 and 35 are formed on this leaf spring by bending its intermediate portion, so that the holder 27 can easily reciprocate in the x direction. Further, the relative positions of the leaf springs 32, 33 and the holder 27 are set such that the axial center lines of the pair of leaf springs 32, 33 and the holder 27 are included in the same plane, and the protrusions 34, 35 are Make it symmetrical about the same plane. A leaf spring 3 is placed opposite both end portions of a pair of permanent magnets 30 and 31.
Iron cores 36 and 37 are arranged on both sides of the iron cores 2 and 33, respectively, and coils 38 and 39 are respectively wound in opposite directions around these iron cores. In the present invention, the ultrasonic transmitting/receiving element 26 includes permanent magnets 30 and 31 and a leaf spring 3 when viewed in the horizontal direction.
2, 33, iron cores 36, 37, and coils 38, 39, and is attached to the holder 27 so that its lower end is located lower than the lower end of the x-direction driving device.
The operation of the scanning device having such a configuration will be explained using FIGS. 4a and 4b.

When current is passed through the coils 38 and 39 in the directions shown in FIG. 4a, the holder is 27 is iron core 3
It is repelled by the 6 side and is attracted to the iron core 37 side, so it receives a rightward force. Therefore, the holder 27 has a leaf spring 32,
Move to the right against 33. Also, the coil 38,
39 in the direction shown in Fig. 4b,
The holder 27 is attracted to the iron core 36 side due to the polarity generated at the tips of the iron cores 36 and 37, and the polarity generated at the tips of the permanent magnets 30 and 31, respectively.
Since it repulses with the iron core 37 side, it receives a force from the left side.
Therefore, the holder 27 moves to the left against the leaf springs 32 and 33. Therefore, if the coils 38 and 39 are connected in series and an alternating current of an appropriate frequency and amplitude is applied, the holder 27 can be vibrated at the same frequency as the alternating current, and the ultrasonic transmitting/receiving element 26 can scan in the x direction. Become.

FIG. 5 is a diagrammatic perspective view showing, with a portion cut away, the structure of an example of a part of the ultrasound microscope according to the present invention. Components similar to those in FIGS. 3 and 4 are denoted by the same reference numerals, and descriptions of similar structures and operations will be omitted. The ultrasonic transmitting/receiving element 26 and its scanning device shown in FIG. 3 are installed in the storage portion 41 at the tip of the support 40 to perform scanning in the x direction. A displacement detector 42 is installed at one end of the holder 27 in the x-direction vibration direction.
Place. An opening 43 is provided below the storage portion 41 so that ultrasonic waves can be transmitted and received through this opening. The support body 40 is formed into an arch shape as shown in the figure, so that there are no obstacles such as the support body below the storage section 41. A sample holding table 45 for holding a sample 44 is arranged in the lower part of this storage section 41. The sample holding table 45 can be moved at low speed in the y direction by a moving mechanism such as a DC motor or a lead screw (not shown). According to the ultrasonic microscope having such a configuration, the ultrasonic transmitting/receiving element 26 is reciprocated at high speed in the x direction, and the sample 44 is moved at low speed in the y direction via the sample holder 45 by a moving mechanism (not shown). 44 can be two-dimensionally scanned by ultrasound. The displacement detector 42 captures the vibration of the ultrasonic transmitting and receiving element that performs high-speed reciprocating motion in the x direction.
Detect and control its amplitude.

As is clear from the above description, according to the ultrasonic microscope according to the present invention, a scanning device is placed next to the sample holding table, and the ultrasonic transmitting/receiving element is scanned upward from the sample through the drive shaft. Since the ultrasonic transmitting/receiving elements and their scanning devices are arranged sequentially, even a large sample with a wide area can be observed in its entirety by using a sufficiently deep support for the scanning device.

Furthermore, since the scanning device becomes smaller, the ultrasonic microscope has the advantage of being easier to design and also being easier to combine with an optical microscope. Further, the ultrasonic transmitting/receiving element is supported by leaf springs from both sides in a direction perpendicular to the vibration direction, and the ultrasonic transmitting/receiving element and one end of each leaf spring are connected by an end surface that substantially coincides with the direction of the ultrasonic beam. Therefore, it is possible to prevent vibrations in directions other than the vibration direction of the ultrasonic transmitting/receiving element, particularly in the direction of the ultrasonic beam, and to avoid harmful effects on ultrasonic images due to unnecessary vibrations.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of an example of a conventional ultrasound microscope, FIG. 2 is a perspective view diagrammatically showing the configuration of another example of a conventional ultrasound microscope, and FIG. FIG. 4 is a perspective view of a main part showing the configuration of an example of a scanning device of an ultrasound microscope, FIG. 4 is a line diagram for explaining the operation of the scanning device of an ultrasound microscope shown in FIG. 1 is a diagrammatic perspective view showing, with a portion cut away, the configuration of a part of an example of an ultrasound microscope according to the invention; FIG. 26... Ultrasonic transmitting/receiving element, 27... Holder, 3
0,31...Permanent magnet, 32,33...Plate spring,
36, 37... Iron core, 38, 39... Coil, 4
0... Support body, 41... Storage section, 42... Opening, 44... Sample, 45... Sample holding stand.

Claims (1)

[Claims] 1. In an ultrasonic microscope that observes a sample by two-dimensional scanning by moving a sample holding table that holds a sample in a first direction and reciprocating an ultrasonic transmitting/receiving element in a second direction perpendicular to the first direction, an excitation means having a holding member that holds the ultrasonic transmitting/receiving element movably in the second direction; and a reciprocating drive mechanism that generates an electromagnetic force that moves the ultrasonic transmitting/receiving element in the second direction. An ultrasonic microscope, characterized in that the ultrasonic transmitting/receiving element is arranged so that its tip is positioned below the lower end of the excitation means when viewed in a horizontal direction.