JPH063438B2 - Ultrasonic microscope - Google Patents

Description

The present invention relates to an ultrasonic microscope, and more particularly to a mechanical scanning ultrasonic microscope.

[Conventional technology]

In an ultrasonic microscope, in order to image a sample to be observed, it is necessary to move the sample and the acoustic lens relatively, that is, to scan. The focal point position of the sonic lens with respect to the sample is a position apart from the sample surface by several tens of μ to several mm, although it depends on the frequency of the ultrasonic wave used for observation. When the sonic lens is arranged at the in-focus position with respect to the sample, the fact that the reflected echo becomes maximum when the sonic lens is located at the in-focus position is used to adjust the distance between the sonic lens and the sample. Was there. However, when the medium for performing sound wave propagation between the sonic lens and the sample, such as water, contains bubbles, or the reflected echo from the sample is small, the maximum point of the reflected echo can be obtained. This could not be done, and there was a risk that the sonic lens and the sample would come into contact with each other at the time of adjusting the interval and damage both of them. Also, if the scanning surface of the sonic lens or the material does not match the sample surface and the sample surface has an inclination, it is necessary to adjust the relative inclination between the sample surface and the scanning surface. There was a high possibility that the sample would come into contact with the sample. Therefore, when the contact occurs during the relative two-dimensional scanning between the sonic lens and the sample, the sonic lens is destroyed and the sample is also scratched,
It becomes unobservable. In order to prevent this contact or collision, the distance between the lens and the sample is measured by ultrasonic waves and a warning is issued when the distance is approached (JP-A-57-182644).
A tool that prevents the lens from hitting the sample is provided on the peripheral edge of the lens so that it does not hit the sample.
Means such as one for detecting contact between the lens and the sample (Japanese Patent Laid-Open No. 60-97258) have been proposed.

[Problems to be solved by the invention]

However, the distance between the lens and the sample is very small,
In addition, since the movement distance of the distance adjustment is even smaller, the work distance is limited unless the measurement accuracy is extremely high in the above method of measuring the distance between the lens and the sample.
Further, if the precision is increased, the device becomes expensive. Moreover, the lens provided with the above-mentioned hit preventive tool can protect the lens, but cannot prevent damage to the sample. Furthermore, if there is no means for quickly separating after detecting the contact,
Similarly, it is impossible to prevent damage to the sample and lens.

[Means for solving problems]

It has been proposed that an air bearing be used for a scanning device of an ultrasonic microscope to perform high-speed non-contact scanning while positioning the lens and the sample with high accuracy (Japanese Patent Laid-Open No. 57-1).
04856), which has been put to practical use. The present invention utilizes this air bearing to detect contact sensitively, and utilizes the gap of the support surface of this air bearing to evacuate at high speed.

[Work]

That is, in the air bearing that performs relative scanning between the sonic lens and the sample, pressure means for detecting the air pressure in the air bearing is provided, and contact with the sample is detected by the pressure detecting means as fluctuation of the air bearing, and The above-mentioned object can be achieved by controlling the pressure balance on both sides of the air bearing by this detection so that the distance corresponding to the gap between the air bearings is rapidly withdrawn.

〔Example〕

An embodiment of the ultrasonic microscope according to the present invention will be described below with reference to the drawings. In the figure, reference numeral 1 is a vibrating plate that supports a sound wave lens 3 via a lens holder 2, and its end portion is X in the figure.
It is connected to a vibration exciter 5 which is a drive source for performing directional vibration. The vibrating plate 1 is supported by a gas bearing, that is, an air bearing 7 whose cross section is shown on the right side in the figure, so that the vibrating operation can be performed. That is, the vibrating plate 1 is provided in the central part of the both by providing the air outlet 7a on the side farther from the sample and the air outlet 7c on the side closer to the sample with the vibrating plate 1 sandwiched therebetween, and by blowing out pressure air from both sides. Supported. In addition, the air outlet 7b is arranged on the side end surface, and both ends of the vibrating plate 1 are moved by the pressure air blown out from both the air outlet (not shown) similarly arranged on the opposite end surface of the vibrating plate 1. It is supported without touching the bearing. b is the air outlet 7a sandwiching the vibrating plate 1
Alternatively, it is a pressure detector that detects a change in the supply air pressure on one side (7c side in the figure) of 7c. Reference numeral 4 denotes a hit preventive attached to the lens holder 2 along with the sonic lens 3, and is installed so as to slightly project from the tip end portion of the sonic lens 3 where the hemispherical hole is formed. A sample 9 is arranged so as to face the acoustic wave lens 3, and is supported by a sample table 8 so as to be scannable in the Y direction in the figure, that is, in the direction orthogonal to the X direction. Reference numeral 10 denotes a scanning controller for synchronizing the X-direction scanning of the vibration exciter 5 and the Y-direction scanning of the sample stage 8 to perform two-dimensional scanning. Reference numeral 11 denotes an abnormality detector connected to the pressure detector 6, which outputs a control signal in response to an input from the pressure detector 6 when the supply pressure in the air bearing 7 changes more than a certain value. is there.
Reference numeral 12 is an air source for supplying compressed air to the air bearing 7, and 13 is a switching valve provided in the middle of a pipe connecting the air source 12 and the air outlets 7a, 7b of the air bearing 7. The switching valve 13 is scanned by the control signal of the abnormality detector 11, and when the pressure detector 6 detects that the supply air pressure to the air bearing 7 has changed, the abnormality detector 11 The air outlet 7a, 7 of the air bearing 7 is activated by the control signal.
The supply of compressed air to b is stopped. The switching valve 13
By this operation, the compressed air is not supplied to the outlets 7a and 7b. Therefore, only the air outlet 7c of the air bearing 7 blows compressed air,
The vibrator 1 is blown closer to the outlet 7a side than the normal support position. 14 is a connector for supplying electric power to the piezoelectric film provided on the sonic lens 2, and 15 is the connector
It is a cable connected to 14.

In this configuration, when observing the sample 9, the vibration controller 5 and the sample table 8 are operated by the command of the scanning controller 10 and the scanning in the X and Y directions is synchronized. That is, the vibrating plate 1 is vibrated in the X direction by the vibrating device 5, and the sample stage 8 is moved in the Y direction by a stepping motor (not shown) or the like in synchronization with the vibrating, so that the sonic lens 3 and the sample 9 The ultrasonic image of the sample 9 is captured by performing a two-dimensional scan relative to the sample 9. Next, it is necessary to set the distance between the sonic lens 3 and the sample 9, that is, to adjust the in-focus position. At this time, if the sonic lens 3 and the sample 9 are brought too close to each other, the hit prevention tool 4 first contacts the surface of the sample 9. An external force is applied to the vibrating plate 1 by this contact, so that the distance between the air bearing 7 and the vibrating plate 1 changes. A change in this interval causes a change in the supply pressure of the outlets 7a and 7c, and the change is detected by the pressure detector 6. And
The abnormality detector 11 outputs the control signal to the switching valve 3 to stop the supply of compressed air to the outlets 7a and 7b. Therefore, in the air bearing 7, the outlet 7
Since the compressed air is supplied only to c, the vibrating plate 1 is separated from the air outlet 7c by the gap between the vibrating plate 1 and the air bearing 7. With this, when the hit preventing tool 4 contacts the sample 9, the vibrating plate 1 can be instantly separated from the sample 9, so that the surface damage of the sample 9 can be minimized. If the hit preventive tool 4 is provided for the sonic lens 3 as well, the hit preventive tool 4 protrudes toward the sample 9 side, so that the hit preventive tool 4 necessarily contacts the sample 9 first. The sonic lens 3 is not damaged.

Further, by outputting the control signal of the abnormality detector 11 to the scan controller 10, the scan controller 10 can also stop the two-dimensional scanning. Therefore, it is possible to prevent the damage of the scanning drive system and the damage of the hit preventive tool 4 and the sample 9 caused by the contact between the hit preventive tool 4 and the sample 9.

According to such a configuration, the sonic lens 3 and the sample 9 do not come into contact with each other, and damage to both can be prevented. In addition, since the vibrating plate 1 is immediately separated from the sample when the hit prevention tool 4 and the sample 9 are in contact with each other, damage to the sample 9 can be suppressed to a minimum. Therefore, the operation of replacing the sonic lens 3 or refinishing the surface of the sample 9 can be eliminated or can be largely eliminated, so that the sample 9 can be efficiently observed.

In addition, in the above-mentioned one embodiment, the embodiment in which the sonic lens is supported by the gas bearing has been described, but the present invention is not limited to this, and also in the ultrasonic microscope of the method of supporting the sample by the gas bearing. It has a similar effect.

〔The invention's effect〕

As described above, according to the present invention, it is possible to immediately detect the contact between the sonic lens and the sample and quickly disconnect the contact.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an ultrasonic microscope according to the present invention. 1 ... Excitation plate, 3 ... Sonic lens, 4 ... Hit prevention device,
5 ... Vibrator, 6 ... Pressure detector, 7 ... Air bearing, 8 ...
… Sample stand, 9 …… Sample, 10 …… Scan controller, 11 …… Abnormality detector.

Claims (3)

[Claims] 1. A sonic lens opposite to a sample, and means for adjusting a distance between the sample and the sonic lens, wherein at least one of a member for supporting the sonic lens and a member for mounting the sample is sonic wave with the sample. The sonic lens is supported along the surface of the sample by being supported by an air bearing in the direction of the interval with the lens, and the member supporting the sonic lens and the member on which the sample is mounted are relatively moved in a direction perpendicular to the interval direction. In the scanning ultrasonic microscope, a pressure detector that detects a pressure change of at least one of the pressure air supplied to the bearing surfaces on both sides of the air bearing, and at least one of the pressure air supplied to the bearing surface is controlled. When the member, which is provided with the means and is supported by the air bearing, is displaced by an external force in the direction of expanding the distance between the sample and the sonic lens, the supply pressure generated by this displacement Ultrasonic microscope by a signal output of the pressure change when the pressure detector detects, characterized in that as the pressure difference is generated on both sides of the air bearing in a direction away and the said sample with sound waves lens. 2. A means for controlling at least one of the compressed air supplied to the bearing surface so that a differential pressure is generated on both sides of the air bearing in a direction in which the sample and the sonic lens are separated from each other, according to claim 1. The ultrasonic microscope, which is a means for stopping the supply of compressed air to the bearing surface that is distant from between the sample and the acoustic lens. 3. The ultrasonic microscope according to claim 1, wherein the sonic lens is a sonic lens provided with a hitting prevention member protruding from a front end of the lens surface on a peripheral portion.