JPH05127682A - Driving noise elimination device for tuning fork, and scanning type microscope - Google Patents

Abstract

PURPOSE:To eliminate the driving noise of the tuning fork by the small-sized driving device consisting of the tuning fork and an exciting means which resonates the tuning fork by making a force varying in strength periodically operate on the tuning fork. CONSTITUTION:The sound generated by the tuning fork 30 arranged in a case 67 is collected by microphones 60a and 60b to obtain a digital sound signal S2, which is inputted to a DSP(digital signal processor) 63. This DSP 63 generates an opposite-phase sound signal S3 which carries a sound wave having the opposite phase from the sound wave of the sound signal S2. Speakers 66a and 66b arranged in the case 67 are driven according to the signal S3 to generate sound waves which are opposite in phase from the sound wave generated by the vibration of the tuning fork 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for resonating a tuning fork by vibrating means, and a device for silencing the sound generated by the vibration of the tuning fork.

The present invention also relates to a scanning microscope in which an optical system for irradiating a sample with illumination light or a sample stage is held by a tuning fork, and the tuning fork is vibrated so that the illumination light is scanned on the sample. is there.

[0003]

2. Description of the Related Art Conventionally, illumination light is converged on a minute light spot, and the light spot is two-dimensionally scanned on a sample, and at that time, light transmitted through the sample or light reflected there, and further a sample An optical scanning microscope is known in which the fluorescence generated from the above is detected by a photodetector to obtain an electric signal carrying an enlarged image of the sample. JP-A-62-217218
The publication discloses an example of this scanning microscope.

In the conventional optical scanning microscope, as the scanning mechanism, the illumination light beam is reflected by an optical deflector.
Many-dimensionally deflecting mechanisms have been used.

However, this mechanism has a drawback that an expensive optical deflector such as a galvanometer mirror or an AOD (acousto-optic optical deflector) is required. Further, in this mechanism, since the illumination light beam is swung by the optical deflector, this light beam is incident on the objective lens of the light-sending optical system at different angles every moment, and the aberrations caused thereby are corrected. Therefore, the problem that the design of the objective lens becomes difficult is also recognized. In particular, when the AOD is used, a special correction lens is required because an astigmatism occurs in the light beam emitted from the AOD in addition to the objective lens, which makes the optical system more complicated.

In view of the above points, conventionally, it has been considered that the illumination light beam is not deflected but the sample stage is moved two-dimensionally to scan the illumination light light spot. Furthermore, as shown in Japanese Patent Application No. 1-246946 by the present applicant, a light-transmitting optical system and a light-receiving optical system are mounted on a common movable table, and the movable table is moved with respect to the sample table. It is also considered that the scanning of the light spot of the illumination light is performed by doing so.

When the optical system and the sample stage are moved relative to each other to scan the illumination light spot as described above, the optical system or the sample stage is moved at high speed in order to shorten the time required for imaging. Is required. As a drive device satisfying such requirements, as shown in Japanese Patent Application No. 3-110234 by the present applicant, a tuning fork and a force whose size periodically changes are applied to the tuning fork. , A vibrating means for resonating the tuning fork has been proposed.

When the tuning fork is made of a magnetic material, the vibrating means is composed of an electromagnet for applying a magnetic field whose strength changes periodically to the tuning fork, and a drive circuit for driving the electromagnet. Can be preferably used. The electromagnet may be formed as a completely separate body from the tuning fork, or may be formed by winding an exciting coil around the tuning fork.

Further, the tuning fork may be formed of a non-magnetic material and the magnetic material may be fixed to the tuning fork.
The magnetic material may be composed of an electromagnet that applies a magnetic field whose strength changes periodically, and a drive circuit that drives the electromagnet.

Further, the vibrating means is formed of a piezoelectric element attached to the tuning fork and a drive circuit for applying a voltage whose magnitude changes periodically to the piezoelectric element to give a cyclically repeated distortion. You can also

When the tuning fork is resonated as described above, a larger amplitude can be obtained as compared with the case where the optical system or the sample stage is directly vibrated by the piezo element or the ultrasonic transducer. Therefore, in this scanning microscope, the relative movement width between the optical system and the sample stage, that is, the illumination light scanning width can be made large.

[0012]

The driving device composed of the tuning fork and the vibrating means can be applied not only to the scanning microscope but also to the advantage that it can vibrate at high speed with a large amplitude. However, on the other hand, it has a drawback that a large noise is generated from the tuning fork when driving.

In order to muffle the driving sound of such a tuning fork, it is conceivable to use a conventionally known sound absorbing material, a side branch or the like. However, the conventional muffler is likely to increase in size or 500 Hz. The following sounds were difficult to mute.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a device that can be formed in a small size and that can satisfactorily muff the drive sound of a tuning fork regardless of its frequency. It is what

Further, according to the present invention, the scanning mechanism for illuminating the light spot of the illumination light is constructed by the tuning fork and the vibrating means, and the driving sound of the tuning fork can be satisfactorily silenced regardless of its frequency. It is intended to provide.

[0016]

According to a first aspect of the present invention, there is provided a drive sound muffling apparatus for a tuning fork, which comprises a tuning fork and a force whose size periodically changes with respect to the tuning fork. In a driving device configured to include a vibrating unit that causes the tuning fork to resonate, a microphone that collects a sound generated by the resonating tuning fork, a speaker that is arranged to emit a sound wave toward the tuning fork, and An amplifier for driving the speaker, a tuning fork and the speaker are housed, and a case where the sound wave emitted from the tuning fork and the wave front of the sound wave emitted from the speaker are aligned, and a sound wave indicated by the signal received by the microphone is received. Signal processing means for inputting a signal for generating a sound wave of opposite phase from the speaker to the amplifier is provided.

Further, according to a second aspect of the present invention, there is provided a drive sound muffling device for a tuning fork, wherein in the drive device including the same tuning fork and vibrating means as described above, a sound wave is directed toward the tuning fork. A speaker arranged to emit sound, an amplifier for driving the speaker, a tuning fork and the speaker are housed, and a case in which the wave fronts of the sound wave emitted from the tuning fork and the sound wave emitted from the speaker are aligned, and the vibrating means are provided. Phase shift means is provided for receiving a frequency signal for driving, phase-shifting the signal by a predetermined amount, inputting it to the amplifier, and making the sound wave emitted by the speaker have a phase opposite to that of the sound wave emitted by the tuning fork. It will be.

According to a third aspect of the present invention, there is provided a driving sound deadening device for a tuning fork according to the present invention.
The polarity of the output signal changes depending on the strength of the two sound waves from the tuning fork and the speaker, and the output signal of this microphone is added to the signal input to the amplifier to detect the sound wave emitted from the speaker. It is characterized in that a signal adding means for converging the amplitude to a magnitude equal to the amplitude of the sound wave emitted by the tuning fork is provided.

On the other hand, the first scanning microscope according to the present invention is
As described above, by moving the sample table on which the sample is placed and the optical system that irradiates the sample with the illumination light, the illumination light is scanned on the sample and the illumination light scanning is performed. In a scanning microscope that photoelectrically detects light from a sample portion to capture a sample image, the moving mechanism that moves the sample table or the optical system to scan the illumination light spot is a sample table or the optical system. And a vibrating means for resonating the tuning fork by causing a force whose size changes periodically to act on the tuning fork, and the first fork having the above-described configuration. The present invention is characterized in that a driving sound muffling device for the tuning fork is provided.

The second scanning microscope according to the present invention comprises:
As described above, by moving the sample table on which the sample is placed and the optical system that irradiates the sample with the illumination light, the illumination light is scanned on the sample and the illumination light scanning is performed. In a scanning microscope that photoelectrically detects light from a sample portion to capture a sample image, a moving mechanism that moves a sample table or an optical system to scan an illumination light spot is a first scanning type. The present invention is characterized by being provided with a second tuning fork driving sound muffling device having the same structure as described above, while being composed of a tuning fork and a vibration means similar to those in a microscope.

[0021]

In each of the muffling devices having the above-described structure, the sound wave emitted from the tuning fork has a phase opposite to that of the sound wave emitted from the speaker, and their wave fronts are aligned by the action of the case, so that they cancel each other out. , The sound from the tuning fork is muted.

And, in particular, the silencer according to the second aspect uses a frequency signal for driving the vibrating means,
Since the signal for generating the anti-phase sound wave is created, the signal processing means for performing the high-level arithmetic processing required by the muffling device according to the first aspect is not required, and it can be formed relatively inexpensively.

The reason why the frequency signal for driving the vibrating means can be used will be described below. When the vibrating means vibrates based on this frequency signal, the tuning fork resonates at that frequency (resonance frequency). At this time, the tuning fork also produces a harmonic sound in addition to the main sound, that is, the sound of the resonance frequency. on the other hand,
A signal obtained by phase-shifting the frequency signal can basically mute only a sound having the same frequency as that of the frequency signal, that is, the main tone. However, in the case of a tuning fork, the intensity of the overtone is about 1/100 to 1/1000 of the intensity of the tonic, and the wave fronts of the sound waves emitted from it are also perfectly aligned, so if the tonic can be silenced, the tuning fork produces almost no noise. Disappear.

The muffler according to claim 2 differs from the muffler according to claim 1 in that it does not generate an antiphase sound wave based on the sound wave actually emitted from the tuning fork. There is a possibility that the amplitude of the sound wave is smaller than the amplitude of the sound wave from the tuning fork and the silencing effect is insufficient, or in the opposite situation, the sound emitted from the speaker becomes new noise.

In order to eliminate such inconvenience, the gain of the amplifier for driving the speaker may be properly set based on the experiment and the experience, or the amplifier may be provided with a volume control according to the mute state. You may operate it.

On the other hand, in the silencer according to the third aspect, the amplitude of the sound wave emitted from the speaker is automatically converged to the amplitude of the sound wave generated from the tuning fork by the action of the microphone and the signal adding means as described above. However, the above problems do not occur.

Since each of the silencers described above is constructed by only an electric circuit and a speaker, or by simply providing a microphone in addition to them, as a whole, as compared with the above-mentioned one using a side branch or the like. It can be made small.

On the other hand, the first scanning microscope according to the present invention is
Since the first muffling device having the muffling effect as described above is provided, it is possible to prevent the tuning fork from emitting a large amount of noise during use, and it is highly quiet and easy to handle. This point is the same in the second scanning microscope provided with the second silencer.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the embodiments shown in the drawings.

FIG. 2 shows a monofocal confocal scanning microscope equipped with a tuning fork driving sound muffling apparatus according to the first embodiment of the present invention, and FIG. 1 shows its scanning mechanism and muffling. The plane shape of the apparatus is shown in detail. Figure 2
As shown in, the monochromatic laser 10 emits the illumination light 11 of a single wavelength. This linearly polarized illumination light 11 is
The light enters the film surface 25a of the polarization beam splitter 25 in a polarized state and transmits therethrough. The illumination light 11 that has passed through the polarization beam splitter 25 passes through a λ / 2 plate 12 for polarization plane adjustment, is condensed by an incident lens 13, and is polarized plane-maintaining optical fiber 14
It is made incident inside.

As the polarization-maintaining optical fiber 14,
As shown in the cross-sectional shape of FIG.
b is arranged, and stress applying portions 14c, 14 are provided on both sides of the core 14b.
A so-called PANDA type in which c is formed is used. And the linearly polarized illumination light 11 is λ / 2
By appropriately rotating the plate 12, the direction of the plane of polarization is aligned with the direction in which the stress applying portions 14c, 14c are arranged or the direction orthogonal thereto (in this example, the latter direction, that is, the arrow U direction in FIG. 3). , Is made to enter the optical fiber 14.

One end of the optical fiber 14 is fixed to the probe 15, and the illumination light propagated in the optical fiber 14
11 is emitted from this end. At this time, one end of the optical fiber 14 emits the illumination light 11 like a point light source. A light sending optical system (also serving as a light receiving optical system) 18 including a collimator lens 16 and an objective lens 17 is fixed to the probe 15. A λ / 4 plate 19 is arranged between the collimator lens 16 and the objective lens 17.

The illumination light 11 is collimated by the collimator lens 16, passes through the λ / 4 plate 19 to be circularly polarized light, is then condensed by the objective lens 17, and is placed on the sample table 22. An image is formed on a minute light spot P on the sample 23 (on the surface or inside). The reflected light 11 ″ reflected by the sample 23 becomes circularly polarized light having a revolving direction in the opposite direction, passes through the λ / 4 plate 19, and is made into linearly polarized light whose polarization plane direction is orthogonal to that of the illumination light 11. The light beam of the light 11 ″ is condensed by the collimator lens 16 and is incident on the polarization-maintaining optical fiber 14. The direction of the plane of polarization of the reflected light 11 ″ at this time is in the direction of the arrow V in FIG. 3. The reflected light 11 ″ propagating through the optical fiber 14 is emitted from one end thereof and is collimated by the lens 13.

This reflected light 11 "passes through the λ / 2 plate 12 and then S
The light enters the film surface 25a of the polarization beam splitter 25 in a polarized state and reflects there. This reflected light 11 "is collected by the condenser lens 26.
Light is collected at the photodetector through the aperture pinhole 27.
Detected by 28. The photodetector 28 is composed of, for example, a photomultiplier (photomultiplier tube), and the like, from which a signal S indicating the brightness of the illumination light irradiation section of the sample 23 is output.

As described above, by providing the optical isolator composed of the λ / 4 plate 19 and the polarization beam splitter 25, the reflected light 11 "is prevented from returning to the laser 10 side, and a larger amount of light is reflected. The light 11 ″ will be guided to the photodetector 28. Further, the illumination light 11 reflected by the entrance lens 13 and the end face of the optical fiber 14 is prevented from entering the photodetector 28, and the signal S with high S / N can be obtained.

Next, the two-dimensional scanning of the light spot P of the illumination light 11 will be described with reference to FIG. The probe 15 is fixed to one end of the horizontally arranged iron tuning fork 30 with the optical axis of the optical system 18 being vertical. The tuning fork 30 has a base portion 30a fixed to a pedestal 32 and can vibrate at a predetermined natural frequency (this point will be described in detail later). An electromagnet 31 is arranged inside the tuning fork 30 at a slight distance from both ends thereof. The electromagnet 31 is fixed to a pedestal 32 via a mounting member 34.

The electromagnet 31 is connected to the tuning fork from the drive circuit 33.
A rectangular pulse current E having a frequency equal to the natural frequency of 30 is applied. In this way, the magnetic field acts intermittently on both ends of the tuning fork 30, so that the tuning fork 30 vibrates at its natural frequency. Therefore, the probe 15 fixed to this tuning fork 30
Moves reciprocally at high speed in the X direction (horizontal direction) in FIGS. 1 and 2, and main scanning of the light spot P is performed.

Further, the sample table 22 moves back and forth with respect to the frame 32 in the Z direction (optical axis direction of the optical system 18) and the Z moving stage 24Z, and in the Y direction perpendicular to both the X and Z directions. It is attached via a possible Y movement stage 24Y. Therefore, when the main scanning of the light spot P is performed as described above, when the Y moving stage 24Y is simultaneously driven to reciprocate, the light spot P is sub-scanned.

Then, each time the light spot P is two-dimensionally scanned, the Z moving stage 24Z is moved so that even if the surface of the sample 23 has fine irregularities, the sample 23
It is possible to obtain a signal S carrying an image in which all surfaces are in focus within the range in which is moved in the Z direction.

As described above, in this scanning microscope, the tuning fork 30 is made to resonate, and this oscillation having a large amplitude is used to perform the main scanning of the illumination light optical point P.
A large main scanning width is secured, and a wide area of the sample 23 can be imaged. In this example, as shown in FIG. 1, a dummy probe 15 'having the same structure as the probe 15 is attached to the other end of the tuning fork 30. This makes it possible to maintain a good mechanical balance at one end and the other end of the tuning fork 30, and to form a resonance system close to an ideal one.

Further, in this example, the electromagnet 31 is arranged inside the tuning fork 30 so that the magnetic fields act on both ends of the tuning fork 30, respectively. Therefore, the electromagnet is provided only outside one end of the tuning fork 30. The magnetic flux density acting on the tuning fork 30, that is, the acting force can be made larger than that in the case of arranging them.

Next, with reference to FIG. 4, the electrical configuration of this scanning microscope will be described. The signal S output from the photodetector 28 described above is amplified by the amplifier 40 and then input to the A / D converter 41, where it is converted into a digital image signal Sd. The image signal Sd is subjected to image processing such as gradation processing in the image processing device 42 and then input to the image reproducing device 43 such as a CRT display device. In the image reproducing device 43, the image carried by the image signal Sd, that is, the microscope image of the sample 23 is reproduced.

A computer 44 such as a personal computer is connected to the image reproducing device 43, and an image processing command and a basic operation command of the scanning microscope, that is, a command for picking up a field-of-view image and an image for observation are provided. Imaging commands, etc.
All are given using the input operation unit such as the keyboard of the computer 44.

The Y moving stage 24Y described above is provided with an oscillator 45.
Is driven so as to reciprocate at the frequency by a driver 46 which receives a signal of a predetermined frequency. The Z moving stage 24Z outputs the Z-axis control signal Fs output from the image processing device 42 and converted into an analog signal by the D / A converter 47.
Is driven by the driver 48 so as to come on a predetermined Z position. The oscillator 45 and the D / A converter 47 are respectively provided with a vertical synchronizing signal Vs, which is issued from the image processing device 42.
The operation is controlled based on the focus direction signal Fs, and the movements of the stages 24Y and 24Z are synchronized.

On the other hand, the electromagnet drive circuit 33 is a pulse generator.
It is composed of 49 and a driver 50 in the subsequent stage. The driver 50 is composed of an open collector buffer 51, a photocoupler 52, a power MOS-FET 53, a diode 54, a capacitor 55, etc., and generates a rectangular pulse current E having the same frequency as the frequency signal Sf input from the pulse generator 49 by the electromagnet 31. Apply to. The pulse generator 49 is an image processing device.
The operation is controlled based on the horizontal synchronizing signal Hs issued from 42, and the movement of the stages 24Y and 24Z and the reciprocating movement of the probe 15 are synchronized.

Next, with reference to FIG. 1, a drive sound muffling device for a tuning fork according to the present invention will be described. Speakers 66a and 66b are arranged above and below the tuning fork 30, respectively. The tuning fork 30 and the speakers 66a and 66b are the case
It is stored in 67. The height of this case 67 is L
Let h be the width, Lw be the distance from the center of the speakers 66a and 66b to the left and right side walls, and let the wavelength of the sound emitted by the tuning fork 30 be λ, then Ls> λ / 2 Lh, Lw <λ / 2 It is formed to meet. Case 67
An openable / closable lid portion 68 is provided for the replacement of the sample 23 and the like.

Two microphones 60a and 60b are provided at the corners of the side wall of the case 67 near the tip of the tuning fork, and their respective output signals S are narrow band filters described later.
It is input to the amplifier 61 through 69. The amplifier 61 synthesizes and amplifies these signals S, and the amplified signal S1 is A / D.
It is input to the converter 62 and digitized. The digital audio signal S2 thus obtained is input to a DSP (digital signal processor) 63.

The DSP 63, based on a predetermined program,
An antiphase audio signal S3 carrying an acoustic wave having an opposite phase to the acoustic wave indicated by the digital audio signal S2 is generated. The digital antiphase audio signal S3 is input to the D / A converter 64 and converted into an analog antiphase audio signal S4. The antiphase audio signal S4 is amplified by the amplifier 65, and the amplified signal S5 is input to the two speakers 66a and 66b. These speakers 66a and 66b are arranged so that the wave front of the sound emitted therefrom is substantially perpendicular to the tuning fork 30.

Two speakers 66a arranged in this way
When the signal S5 is input to the terminals 66 and 66b, the speakers 66a and 66b generate sound waves having a phase opposite to that of the sound waves generated by the vibration of the tuning fork 30. Then, the sound waves emitted from the tuning fork 30 and the sound waves emitted from the speakers 66a and 66b are aligned with each other by the action of the case 67 having the above-described shape. As a result, these two sound waves cancel each other out, and the tuning fork 30 does not emit a loud sound.

The silencer of the first embodiment is a DSP.
There is an advantage that even if the frequency of the sound generated by the tuning fork 30 changes, it can be dealt with by changing the coefficient for calculating the antiphase of 63.

Further, in the muffler of this embodiment, each output signal S of the microphones 60a and 60b is passed through the narrow band filter 69 which passes only the signal component of the single tone generated by the tuning fork 30 and its overtone. , It is possible to minimize the influence of external noise other than the tuning fork 30. The narrow band filter 69 may be composed of a known comb filter or the like.

Next, a second embodiment of the present invention will be described with reference to FIGS. The tuning fork 30, which is silenced by the device of the second embodiment, is also an electromagnet connected to the electromagnet drive circuit 33.
It is excited by 31. This electromagnet drive circuit
Since 33 is the same as the one shown in FIG. 4, a description thereof will be omitted. Also, in FIGS. 5 and 6, the same elements as those already described are given the same reference numerals,
The duplicated description thereof will be omitted.

In this embodiment, the frequency signal Sf output from the pulse generator 49 of the electromagnet driving circuit 33 which constitutes the vibrating means is input to the phase shifter 70. The phase shifter 70 phase-shifts (delays) the frequency signal Sf by a predetermined amount and outputs it as an audio signal S6. Note that this phase shift amount is λ where the wavelength of the sound wave emitted by the tuning fork 30 is λ, and the left and right side walls from the center of the speakers 66a and 66b (the wave surface of the sound wave emitted from the tuning fork 30 and the wave surface of the sound wave emitted from the speakers 66a and 66b are aligned. Is Ls, tuning fork 30
Let Lt be the distance from the center of thickness to the left and right sidewalls, and set to −2π (Ls−Lt) / λ + π.

The voice signal S6 is a signal adder described later.
The signal S7 is sent through 71, and this signal S7 is a speaker.
It is input to the amplifier 65 that drives 66a and 66b. tuning fork
30 vibrates at a frequency (resonance frequency) equal to the frequency based on the frequency signal Sf. On the other hand, when the speakers 66a and 66b are driven based on the signal S7 obtained by phase-shifting the frequency signal Sf by the above amount,
From these speakers 66a and 66b, a sound wave having a phase opposite to the vibration of the tuning fork 30, that is, a sound wave having a phase opposite to the sound wave generated by the vibration is emitted. This prevents the tuning fork 30 from producing a loud sound even in this device.

In order to prevent the above-mentioned muffling effect from becoming insufficient, or conversely, the problem that the sounds emitted from the speakers 66a and 66b become new noise, the gain of the amplifier 65 should be set appropriately as described above. Setting is also one method. However, in this embodiment, the amplitudes of the sound waves emitted from the speakers 66a and 66b are automatically converged to a magnitude equal to the amplitude of the sound waves generated by the tuning fork 30. Hereinafter, that point will be described.

Microphones 60a and 60b are provided on the side wall portions on both sides of the tuning fork 30 so as to vertically receive the wave front of the sound generated by the tuning fork vibration. The output signals S of the microphones 60a and 60b are input to the amplifier 61. The amplifier 61 combines and amplifies these signals S, and the amplified signal S1 is input to the phase shifter 72. The phase shifter 72 phase shifts (delays) this signal S1 by a predetermined amount.
Then, the correction signal S8 is output. The phase shift amount is set to −2π (Ls−Lt) / λ + π, similarly to the phase shift of the frequency signal Sf described above.

The above-mentioned correction signal S8 is input to the signal adder 71, where it is added to the audio signal S6 to form a signal S7. When the microphones 60a and 60b are arranged in the above-described direction, the polarity of the signal S, that is, the correction signal S
The polarity of 8 is reversed when the amplitude of the sound waves emitted from the speakers 66a and 66b is smaller than the amplitude of the sound waves generated by the tuning fork 30 and vice versa. That is, assuming that the correction signal S8 has the waveform shown in (2) of FIG. 7 in the former case, the waveform of the correction signal S8 in the latter case is
It becomes what is shown in (2) of FIG.

In the former case, the correction signal S8 is the audio signal S6.
, The signal S7 after addition has a larger amplitude than the audio signal S6 (see (1) and (3) in FIG. 7).
By inputting such a signal S7 to the amplifier 65, the amplitudes of the sound waves emitted from the speakers 66a and 66b gradually increase and finally become equal to the amplitudes of the sound waves generated by the tuning fork 30. On the other hand, in the latter case, when the correction signal S8 is added to the audio signal S6, the added signal S7 becomes the audio signal S6.
The amplitude is lower than that (see (1) and (3) in FIG. 8). By inputting such a signal S7 to the amplifier 65, the amplitudes of the sound waves emitted from the speakers 66a and 66b gradually decrease and finally become equal to the amplitudes of the sound waves generated by the tuning fork 30. As described above, in the device of this embodiment, the amplitude of the sound waves emitted from the speakers 66a and 66b automatically becomes equal to the amplitude of the sound waves generated by the tuning fork 30.

Depending on the directions of the microphones 60a and 60b and the structure thereof, the waveform of the correction signal S8 is contrary to the above, and the amplitudes of the sound waves emitted from the speakers 66a and 66b are
If the amplitude of the sound wave generated by the tuning fork 30 is smaller than that shown in FIG. 8 (2), the opposite case can be obtained as shown in FIG. 7 (2). In such a case, the polarity of the correction signal S8 may be inverted and added (that is, subtracted) to the audio signal S6.

Although the scanning microscope described above is of a monochrome reflection type, the present invention is not limited to this, and a scanning microscope for picking up a color image, a transmission scanning microscope, a scanning fluorescence microscope, etc. It is also applicable to. Also,
The tuning fork driving sound muffling device according to the present invention is applicable not only to a driving device that reciprocates the optical system of the scanning microscope and the sample stage, but also to any driving device that reciprocates other moving bodies by the vibration of the tuning fork. Is.

Further, the present invention is not limited to the vibrating means formed by the electromagnet and the drive circuit thereof, and also for the apparatus using the vibrating means formed of, for example, the piezoelectric element and the drive circuit thereof. It is applicable as well.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a first embodiment device of the present invention.

FIG. 2 is a partially cutaway front view showing a scanning microscope to which the apparatus of the first embodiment is applied.

FIG. 3 is a sectional view of a polarization-maintaining optical fiber used in the scanning microscope.

FIG. 4 is an electric circuit diagram of the scanning microscope.

FIG. 5 is a schematic plan view showing a second embodiment device of the present invention.

FIG. 6 is a partially cutaway front view showing a scanning microscope to which the apparatus of the second embodiment is applied.

FIG. 7 is a graph showing a signal waveform in the second embodiment device.

FIG. 8 is a graph showing a signal waveform in another case in the device of the second embodiment.

[Explanation of symbols]

 10 Monochromatic laser 11 Illumination light 11 ”Reflected light 14 Polarization-maintaining optical fiber 15 Probe 16 Collimator lens 17 Objective lens 18 Transmitting optical system 22 Sample stage 23 Sample 26 Focusing lens 27 Aperture pinhole 28 Photodetector 30 Tuning fork 31 Electromagnet 32 Frame 33 Electromagnet drive circuit 46, 48, 50 Driver 49 Pulse generator 60a, 60b Microphone 61, 65 Amplifier 62 A / D converter 63 Digital signal processor 64 D / A converter 66a, 66b Speaker 67 Case 69 Narrow band filter 70, 72 Phase shifter 71 Signal adder

Claims (5)

[Claims] 1. A drive device comprising a tuning fork and a vibrating means for causing the tuning fork to resonate by applying a force whose magnitude changes periodically to the tuning fork. A microphone for collecting sound, a speaker arranged to emit a sound wave toward the tuning fork, an amplifier for driving the speaker, the tuning fork and the speaker are housed, and the sound wave emitted from the tuning fork and the sound emitted from the speaker A case for aligning the wavefronts of the generated sound waves, and a signal processing unit for receiving a signal output from the microphone and inputting a signal for generating a sound wave having a phase opposite to that of the sound wave from the speaker from the speaker to the amplifier. Naru tuning fork drive sound muffling device. 2. A drive device comprising a tuning fork and a vibrating means for causing the tuning fork to resonate by causing a force whose size changes periodically to act on the tuning fork. A speaker arranged to emit the sound, an amplifier for driving the speaker, the tuning fork and the speaker housed, and a case in which the wave fronts of the sound wave emitted from the tuning fork and the sound wave emitted from the speaker are aligned, Phase shift means for receiving a frequency signal for driving the means, phase-shifting the signal by a predetermined amount and inputting it to the amplifier, and making the sound wave emitted by the speaker have a phase opposite to that of the sound wave emitted by the tuning fork. Drive sound muffling device for tuning forks. 3. A microphone is arranged such that the polarity of the output signal changes depending on the strength of two sound waves generated by the tuning fork and the speaker, and the output signal of the microphone is added to the signal input to the amplifier. 3. The drive sound muffling device for a tuning fork according to claim 2, further comprising signal adding means for converging the amplitude of the sound wave emitted by the speaker to a magnitude equal to the amplitude of the sound wave emitted by the tuning fork. 4. A sample table on which a sample is placed and an optical system for irradiating the sample with illumination light are relatively moved to scan the illumination light on the sample, and the illumination light is scanned. In a scanning microscope that photoelectrically detects light from a received sample portion to capture a sample image, a moving mechanism that moves the sample stage or the optical system, and a tuning fork holding the sample stage or the optical system, The driving sound muffling device for a tuning fork according to claim 1, wherein the tuning fork comprises a vibrating unit that resonates the tuning fork by applying a force of which the magnitude changes periodically. A scanning microscope. 5. A sample table on which a sample is placed and an optical system for irradiating the sample with illumination light are relatively moved to scan the illumination light on the sample, and the illumination light scanning is performed. In a scanning microscope that photoelectrically detects light from a received sample portion to capture a sample image, a moving mechanism that moves the sample stage or the optical system, and a tuning fork holding the sample stage or the optical system, The driving sound muffling device for a tuning fork according to claim 2, wherein the tuning fork comprises a vibrating means for causing a force of which the magnitude changes periodically to cause the tuning fork to resonate. A scanning microscope.