Scanning apparatus for a scanning microscope

A scanning apparatus for scanning which is used in a scanning microscope having an observation apparatus for observing a sample wherein the sample is secured in order to obtain an image of the same. The scanning apparatus includes a moving apparatus for moving at least either the sample or the observation apparatus in order to scan the sample, and a vibration attenuating element structurally provided for the moving apparatus for attenuating relative vibration between the sample and the observation.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a scanning apparatus for a scanning 
microscope, and particularly relates to a lens scanning apparatus for an 
ultrasonic microscope. 
2. Related Art Statement 
In recent years, an ultrasonic microscope has been put to practical use in 
which a sample to be observed is two-dimensionally scanned with an 
ultrasonic beam and reflected waves or transmitted waves from the sample 
are received to form an ultrasonic image of the sample. In the ultrasonic 
microscope, a sample should be scanned through relatively two-dimensional 
moving a lens and a sample. As such a scanning method, there are various 
methods including a method of scanning a lens in the X direction and 
scanning a sample in the Y direction, a method of scanning a lens and a 
sample in the X-Y direction and so on. Also, although there are various 
means for scanning a lens or a sample in the X-Y direction, one of such 
means is the X-Y scanner used for a low temperature ultrasonic microscope, 
shown on pages 17 and 18 in Acoustical Imaging, Vol. 12. 
In this X-Y scanner, for example, a lens supporting stand for supporting a 
lens is fitted to a scanner supporting stand through a spring(tube). A 
coil is fitted to this lens supporting stand, but on the other hand, a 
magnet is fitted to the scanner supporting stand. By these coil and 
magnet, the lens supporting stand can be moved in the X-Y direction. 
The above mentioned scanner has superior features in several points, but on 
the other hand, if the above mentioned spring is made to be inelastic so 
as to be able to drive the electric power as small as possible, the 
scanner is easily vibrated by a variation coming from the outside, by 
noise of a driving signal, by relative harmonic contents and so on. Such a 
variation becomes a deflection of the picture image and will remarkably 
reduces the quality of a picture. Therefore, an electrical counterplan 
such as a servomechanism, has been usually considered; however, the 
counterplan is not enough, especially for above mentioned several noises 
of a frequency near the resonance point. 
OBJECT AND SUMMARY OF THE INVENTION 
An object of the present invention is to provide a scanning apparatus for a 
scanning microscope wherein vibration can be reduced. 
The scanning apparatus for the scanning microscope of the present invention 
is used in a scanning microscope having an observation device for 
observing a sample wherein the sample is scanned in order to obtain an 
image of the sample, and comprises a moving device for moving at least 
either the sample or the observation device in order to scan the sample 
and a vibration attenuating device structurally provided for the moving 
device for attenuating relative vibration between the sample and the 
observation device. 
The other features and advantages of the present invention will become 
apparent in the following explanation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The first embodiment of the present invention is shown in FIGS. 1 and 2. 
As shown in FIG. 2, the low temperature ultrasonic microscope applied to 
this embodiment has a base 1 below which a low temperature tank 2 as an 
adiabatic container is sealed and fitted. Liquid nitrogen 3 which is an 
ultrasonic wave transferring medium is contained in this low temperature 
tank 2 which is a double vacuum structure of triple containers 2a, 2b and 
2c and within which an annular tank 4 is provided. A pipe 5 is led into 
the annular tank 4 through the outside container 2a so that liquid 
nitrogen may be enclosed through this pipe 5. The temperature elevating 
action from the outside is to be prevented by the annular tank 4 enclosing 
this liquid nitrogen. The respective side walls of the containers 2a, 2b 
and 2c of the above mentioned low temperature tank 2 are provided 
respectively with peep holes 6a, 6b and 6c through which the distance 
between the acoustic lens and sample can be confirmed from the outside. 
The above mentioned base 1 has an opening 1a in the central part. Four 
scanner supports 7 are provided to project downward on the lower surface 
of the base 1 around this opening 1a. Only two scanner supports 7 are 
shown in FIG. 2. A scanner supporting stand 30 is fitted to the lower ends 
of these scanner supports 7. A X-Y scanner 31 is fitted to the scanner 
supporting stand 30 to which an acoustic lens 32 is fitted. This acoustic 
lens 32 is to be two-dimensional driven in an XY plane intersecting at 
right angles with a paper surface by the above mentioned X-Y scanner 31. 
A sample rod 11 is inserted into the above mentioned low temperature tank 2 
through the opening 1a of the above mentioned base 1 and is arranged in 
the Z direction upward of the above mentioned acoustic lens 32. A sample 
stand 12 is fitted to the lower end of this sample rod 11 and is to be 
fitted with a sample to be observed. The high frequency electric power 
generated from a transmitter (which is not shown in the figures) is 
converted to ultrasonic waves by a piezoelectric transducer bonded to the 
acoustic lens 32 through a circulator, which is also not shown in the 
figures. These ultrasonic waves are converged by the above mentioned 
acoustic lens 32 and the ultrasonic beam emitted from this acoustic lens 
32 reaches the sampled through the liquid nitrogen 3 which is a 
transferring medium. Therefore, the sample will be two-dimensionally 
scanned by the ultrasonic beam. The reflected waves from the sample are 
concentrated by the above mentioned acoustic lens 32, are converted to an 
electric signal by the above mentioned piezoelectric transducer and this 
electric signal is converted to a picture signal by the above mentioned 
piezoelectric transducer and this electric signal is converted into a 
picture signal by a signal processing circuit through the above mentioned 
circulator and a signal processing circuit, which is not shown in figures. 
This picture signal is input into a monitor (which is not shown in the 
figures) in which an ultrasonic image is to be displayed. 
The above mentioned sample rod 11 is formed of a hollow pipe, for example, 
of stainless steel. If the above mentioned sample rod 11 is formed of a 
material of the same thermal expansion coefficient of the scanner support 
7, even if the liquid level of the liquid nitrogen 3 varies, the sample 
will be able to be prevented from being displayed in the Z direction with 
respect to the acoustic lens 32. An annular adiabatic member 14 is 
arranged near the opening of the above mentioned low temperature tank 2 to 
attain the adiabatic effect on the opening side. 
On the other hand, an X-Y-Z stage 21 for moving the above mentioned sample 
rod 11 in X, Y and Z directions is fitted on the above mentioned base 1 
and a bellows 22, through which the above mentioned sample rod 11 is 
inserted, is fitted on the upper surface of the base 1 around the opening 
1a of the above mentioned base 1. A movable table 23 of the above 
mentioned X-Y-Z stage 21, in which the above mentioned sample rod 11 is 
inserted, is fitted on the upper end of this bellows 22. When the sample 
is observed, the sample rod 11 is moved in the directions of X, Y and Z by 
the X-Y-Z stage 21 so as to select observation parts and to adjust focus. 
A sliding seal 25 is fitted on the upper surface of the above mentioned 
movable table 23 so as to airtightly seal the low temperature tank 2 and 
the outside, and to fix the above mentioned sample rod 11. 
The X-Y scanner 31 of this embodiment is formed as shown in FIG. 1. 
An opening is provided in the central part of the above mentioned scanner 
supporting stand 30 and a cylindrical body 33 in which the bottom is 
blocked is provided below the opening. On the upper surface of the bottom 
of this body 33, for example, a metallic supporting pipe 35, which 
functions as a spring facing upward, is provided. The upper part of this 
pipe 35 projects over the above mentioned scanner supporting stand 30 and 
a lens supporting stand 36 is provided on the upper end of the pipe 35. 
The above mentioned acoustic lens 32 is fitted on the lens supporting 
stand 36. On the upper surface of the outer circumference of the above 
mentioned lens supporting stand 36, a coil 37 is fitted. On the upper 
surface of the above mentioned scanner supporting stand 30, a yoke 38 is 
fitted as if the above mentioned coil 37 is put between the yoke 38 from 
the upper and lower sides. A magnet 40, which is opposing to the above 
mentioned coil 37 at a predetermined interval from the upper and lower 
sides, is fitted to the inside of the yoke 38. By applying an electric 
current to the above mentioned coil 37, the above mentioned lens 
supporting stand 36 moves in the X-Y direction by the power derived from 
the magnetic field based on the electric current of the coil 37 and the 
above mentioned magnet 40 so that the above mentioned acoustic lens 32 may 
scan the above mentioned sample 12 in the X-Y direction. 
In this embodiment, gum 41 which is a damper material is affixed as a 
structural vibration attenuating means to the outer circumference of the 
above mentioned pipe 35 which functions as a spring for the above 
mentioned X-Y scanner 31 in order to reduce a Q value of resonance. 
Thus, in the embodiment, since the structural vibration attenuating means 
through the gum 41 is provided in the X-Y scanner 31, the vibration coming 
from the outside, the vibration caused by the noise of the driving signal 
and the vibration caused by the higher harmonics contents of the driving 
signal and so on can be reduced. Accordingly, deflection of the picture 
image through the vibration can be prevented and it will become possible 
that the spring(pipe 35) is made to be inelastic so as to be able to drive 
by electric power as small as possible. 
Furthermore, since it is not always necessary that the vibration 
attenuating means affixed to the pipe 35 should be gum, such as soft resin 
is suitable. 
The second embodiment of the present invention is shown in FIG. 3. 
In this embodiment, liquid 51, which is stable and has appropriate 
viscosity, a low steam pressure (for example, oil for a rotary pump) and 
low melting pint, is contained in the body 33 in which the pipe 35 
functions as a spring of the X-Y scanner 31 is installed. The motion of 
the pipe 35 is applied damping by hydrodynamic friction(viscous drag) 
between the liquid 51 and the pipe 35 so that the vibration of the pipe 35 
is attenuated by viscous damping. 
It i not always necessary that the X-Y scanner 31 is used to turn the 
acoustic lens 32 upward as shown in the figures, and in some cases, the 
acoustic lens 32 is turned over upside down, and there are many cases that 
it is convenient to use the acoustic lens 32 so as to turn the lens 
downward. In this case, it is necessary to put on a lid of small 
resistance so that the liquid 51 may not flow out and the movement of the 
pipe 35 may not be disturbed. Then, in this embodiment, a ring magnet 52 
is fitted to the inner circumference of the opening of the body 33, and 
magnetic fluid 53 is fitted between the inner circumference of the ring 
magnet 52 and the above mentioned pipe 35 so that the inner circumference 
is closed by the magnetic fluid 53. 
The others are of the same formation, operations and effects as in the 
first embodiment. 
The third embodiment of the present invention is shown in FIG. 4. 
In the first embodiment, the gum 41 is affixed as a damper material to the 
supporting pipe 35 which fills the role of a spring for the X-Y scanner 
31; however, in this embodiment, a plurality of wings(or fins) 61 are 
fitted to the above mentioned supporting pipe 35 in place of the gum 41, 
and the wings 61 are projecting in the cooling liquid(liquid nitrogen 3) 
around the supporting pipe 35. 
In this embodiment, the motion of the pipe 35 fitted with the above 
mentioned wings 61 is applied damping by the viscous drag for the wings 61 
in the above mentioned cooling liquid so that the vibration of the pipe 35 
is attenuated by the viscous damping. 
The others are of the same formation, operations and effects as in the 
first embodiment. 
The fourth embodiment of the present invention is shown in FIG. 5. 
In this embodiment, a supporting pipe 65 composed of a nonresonance 
alloy(such as the product name of SILENTALLOY of Toshiba, Inc.) as a 
material is provided instead of the supporting pipe 35 on which the gum 41 
is affixed in the first embodiment. That is to say, this embodiment 
supplies the supporting pipe 65 with a damping effect by the material 
itself. 
The others are of the same formation, operations and effects as in the 
first embodiment. 
Further, the present invention is not restricted by the above each 
embodiment. For example, the scanning apparatus may also scan by moving a 
sample and without moving a lens. The present invention can be also 
applied to a transmission type ultrasonic microscope in which ultrasonic 
waves have passed through the sample during the waves are dispersing and 
attenuating and are converted into picture images. 
Also, the present invention can be applied not only to an ultrasonic 
microscope but also to a scanning apparatus of a microscope wherein 
scanning is needed. Furthermore, besides microscopes, the present 
invention can be applied to a mechanical scanning apparatus such as an 
ultrasonic diagnostic apparatus and an ultrasonic endoscope. 
As explained above, according to the present invention, there are effects 
that a vibration can be attenuated because a structural vibration 
attenuating means is provided in a scanning apparatus for the scanning 
microscope. 
It is apparent that, in this invention, working modes different in a wide 
range can be formed on the basis of this invention without departing from 
the spirit and scope of the invention. This invention is not restricted by 
its specific working modes except being limited by the appended claims.