JP3453565B2 - Micro vibration detection device and micro vibration control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly sensitive microvibration detection device and microvibration control device using a superconductor.

[0002]

2. Description of the Related Art In a conventional microvibration detecting apparatus, a cantilever beam is formed using a silicon substrate 131 as shown in FIG. 13, a weight 132 is attached to the tip of the cantilever beam, and an electrode ( A typical example is an acceleration sensor (not shown). When this acceleration sensor receives an acceleration α in the z direction, a force of F = mα is applied to the weight 132 (assuming the mass is m) at the tip of the cantilever, and the flexed portion 133 bends.

As a result, the flexure 133 is caused by the piezoresistive effect due to the stress T generated in the flexure 133.
Changes its resistance, and minute vibrations are detected by measuring this resistance change with an electrode (not shown) attached to the bending portion. The amount of change in the resistance is proportional to the stress T as expressed by the following equation.

| Δρ | = ρ | π || T | ρ: resistivity without strain Δρ: amount of change in resistivity due to stress π: piezoresistance coefficient A microvibration detecting device using such a semiconductor is Since semiconductor processing technology can be used, the sensitivity can be improved by improving the processing accuracy of the sensor, downsizing, or devising the shape of the flexure.

[0005]

The conventional microvibration detecting device described above has the following problems because it utilizes the deflection of the cantilever. For example, the sensitivity of small vibration detection,
In order to improve accuracy, reduce the thickness of the flexure,
It is sufficient to increase the mass of the weight, but in this case, the mechanical strength of the flexible portion is reduced. In addition, the bending portion may be deformed not only in the z direction, which is the acceleration measurement direction, but also in the y direction and the twist direction.

Therefore, the resistance generated from the deflection other than the z direction is also measured, and the z direction resolution of the acceleration is lowered. In the case of an acceleration sensor using a cantilever, it is possible to measure the velocity in the one-dimensional direction, but when measuring in the two-dimensional and three-dimensional directions, two or three sensors must be used, so each sensor It is necessary to correct the sensitivity of. In addition, there are non-linearity and aging of the piezoresistive effect.

It is an object of the present invention to provide a microvibration detecting device having high mechanical reliability, capable of distinguishing twist and deflection, that is, detecting three-dimensional behavior, excellent in linearity, and having little change with time. It is in.

[0008]

First of Related Reference Inventions
Of the microvibration detecting device, a superconductor, a magnetic circuit for generating a magnetic field for levitating the superconductor by the Meissner effect, an electromagnetic wave irradiation source, and a position change of the levitated superconductor. In a microvibration detecting device having a detector for detecting using electromagnetic waves, the detector for detecting the position change is a superconducting sensor using a Josephson junction, and the superconductor and the superconducting sensor are It is provided with a cooling device for cooling together, the position detection of the floating superconductor, by detecting the electromagnetic wave reflected or projected from the superconductor of the electromagnetic wave of the electromagnetic wave irradiation source by the superconducting sensor. It is characterized by being performed.

The superconducting sensor can be a one-dimensional or two-dimensional array of superconducting line sensors in which the Josephson junctions of the Josephson junction series array have different normal resistance values. .

The position of the levitated superconductor is detected because electromagnetic waves applied to the superconductor are applied from 1, 2 or 3 directions.
Two or three dimensional detection can be performed.

The superconductor may be, for example, a sphere, a plate, a rod, a processed body thereof, a structure in which the superconductor is dispersed, or a material obtained by processing the superconductor into a sphere, a plate, a rod, or the like. It is a structure with a superconductor attached to the surface or inside.

A second microvibration detecting apparatus of the related reference invention is a superconductor, a magnet levitated by the Meissner effect of the superconductor, an electromagnetic wave irradiation source, and a position change of the levitated magnet, which is irradiated by the electromagnetic wave. In a microvibration detecting device having a detector for detecting using electromagnetic waves of a source, the detector for detecting the position change is a superconducting sensor using Josephson junction, and the superconductor and the superconducting sensor. And a cooling device for cooling the same, and the position of the floating magnet is detected by detecting the electromagnetic wave reflected or projected from the magnet of the electromagnetic wave of the electromagnetic wave irradiation source by the superconducting sensor. It is characterized by

The superconducting sensor can be a one-dimensional or two-dimensional array of superconducting line sensors in which the Josephson junctions of the Josephson junction series array have different normal resistance values. .

The position of the levitated magnet is detected by electromagnetic waves applied to the magnet from one, two, or three directions, so that one-, two-, or three-dimensional detection is performed. be able to.

The first microvibration detecting device of the present invention has a superconductor and a magnetic circuit for generating a magnetic field for levitating the superconductor by the Meissner effect. In the micro vibration detection device that detects the position,
A light source that emits coherent and uniform wavelength light, a reflector provided on the superconductor, a reference reflector provided on the magnetic circuit, and light from the light source on the reflector and the reference reflector, respectively. And an optical system for effectively modulating the frequency of one of the reflected light from the reflector and the reference reflector in the spatial direction, and an interference pattern between the modulated light and the unmodulated light. Imaging means for imaging
Processing means for processing the output of the imaging means and converting it into a signal indicating the optical position of the superconductor.

A second microvibration detecting device of the present invention is a microvibration detecting device which has a superconductor and a magnet which is levitated by the Meissner effect of the superconductor, and which detects the optical position of the levitated magnet. A light source that emits coherent and uniform-wavelength light, a reflector provided on the magnet, a reference reflector provided on the superconductor, and light from the light source on the reflector and the reference reflector, respectively. And an optical system for effectively modulating the frequency of one of the reflected light from the reflector and the reference reflector in the spatial direction,
It is characterized by further comprising: imaging means for imaging the interference pattern of the modulated light and the unmodulated light; and processing means for processing the output of the imaging means and converting it into a signal indicating the optical position of the magnet. .

The third microvibration detecting device of the present invention has a superconductor and a magnetic circuit for generating a magnetic field for levitating the superconductor by the Meissner effect. In the micro vibration detection device that detects the position,
A light source that emits coherent and uniform wavelength light, a reflector provided on the superconductor, a reference reflector provided on the magnetic circuit, and an optical system that modulates the frequency of the light from the light source, An optical system for irradiating the reflection plate and the reference reflection plate with modulated light and unmodulated light, respectively, first and second light intensity sensing means for detecting the intensity of incident light, and the modulated light. An optical system that causes unmodulated light to enter the first light intensity sensing means and interferes with these lights, and second reflected light from the reflector and the reference reflector
Signal for changing the position of the superconductor by changing the output of the first and second light intensity sensing means into the light intensity distribution and the optical system for making these light beams interfere with each other. And a processing unit for converting into.

A fourth microvibration detecting device of the present invention is a microvibration detecting device which has a superconductor and a magnet levitated by the Meissner effect of the superconductor, and which detects the optical position of the levitated magnet. A light source that emits coherent and uniform wavelength light, a reflector provided on the magnet, a reference reflector provided on the superconductor, and an optical system that modulates the frequency of the light from the light source, An optical system for irradiating the reflection plate and the reference reflection plate with modulated light and unmodulated light, respectively, first and second light intensity sensing means for detecting the intensity of incident light, and the modulated light. An optical system that causes unmodulated light to enter the first light intensity sensing means and interferes with these lights, and reflected light from the reflector and the reference reflector enter the second light intensity sensing means and these Light that interferes with the light of And the system, the outputs of the first and second light intensity sensing means to change the intensity distribution of the light, and having a processing means for converting a signal indicating the position change of the superconductor.

A first microvibration control device of the present invention has a superconductor and a magnetic circuit capable of electrically controlling magnetic force for generating a magnetic field for levitating the superconductor by the Meissner effect. In a microvibration control device that controls microvibration of a floating superconductor, a light source that emits coherent and uniform-wavelength light, and a reflector provided on the superconductor,
A reference reflector provided in the magnetic circuit, an optical system for irradiating the reflector and the reference reflector with light from the light source, respectively, and one frequency of light reflected from the reflector and the reference reflector. An optical system that effectively modulates light in the spatial direction, an imaging unit that images the interference pattern between the modulated light and the unmodulated light, and the output of the imaging unit is processed to indicate the position of the superconductor. It is characterized by comprising processing means for converting into a signal and control means for controlling the magnetic force of the magnetic circuit based on the output of the processing means.

A second microvibration control device of the present invention has a superconductor and a magnetic circuit capable of electrically controlling magnetic force for generating a magnetic field for levitating the superconductor by the Meissner effect. In a microvibration control device that detects the optical position of a floating superconductor, a light source that emits coherent and uniform-wavelength light, and a reflector provided on the superconductor,
A reference reflector provided in the magnetic circuit, an optical system for modulating the frequency of light from the light source, and an optical system for irradiating the reflector and the reference reflector with modulated light and unmodulated light, respectively. First to detect the intensity of incident light
And a second light intensity sensing means, an optical system that causes the modulated light and the unmodulated light to enter the first light intensity sensing means, and interferes these lights, and the reflector and the reference reflector. An optical system that causes the reflected light of the above to enter the second light intensity receiving means and interferes with these lights, and the outputs of the first and second light intensity receiving means are changed to the light intensity distribution, and the superconductor And a control means for controlling the magnetic force of the magnetic circuit based on the output of the processing means.

(Operation) First and Second Related Reference Inventions
In the microvibration detection device of, when relative vibration occurs between the magnetic circuit (or superconductor) and the superconductor (or magnet) that is a levitation body, the Meissner effect causes the centerline of the magnetic circuit or superconductor to move. Levitating body and magnetic circuit
The relative position with (or superconductor) changes due to microvibration. This change in relative position is detected by a superconducting sensor as a detector.

Further, by arranging the electromagnetic wave generation source and the detector in the two-dimensional or three-dimensional direction, it is possible to detect the two-dimensional or three-dimensional displacement. further,
In the first and second minute vibration detection devices of the present invention, not only is the electromagnetic wave from the electromagnetic wave generation source applied to the levitating body that is levitated by the Meissner effect and the position change is detected by the projected wave, but the electromagnetic wave is also detected. Change the arrangement of the detector to detect,
The position change can also be detected by the reflected wave.

As described above, the first and second minute vibration detecting devices of the related reference invention utilize the superconductor and its Meissner effect instead of the conventional mechanical strain of the semiconductor. This is to enable accurate detection of minute vibrations from three dimensions to three dimensions.

Further, in both the present invention and the related invention, since the Meissner effect of the superconductor is utilized, it is necessary to cool a part or the whole of the device to a temperature below the critical temperature of the superconductor. The critical temperature of superconductors is about
130K, and even with this material, the detector part for electromagnetic waves (eg visible light) is often lower than about 80K. If a normal optical sensor is used in this temperature range, problems such as sensitivity decrease and operation speed decrease may occur depending on the sensor, so the detector part and the floating superconductor part are thermally separated. There is a need.

In the first and second microvibration detecting devices of the related invention, in order to detect microvibration with high precision without performing such thermal separation, the detector also uses a superconductor sensor. It is a thing. By arranging such superconducting sensors one-dimensionally or two-dimensionally and measuring the output from each superconducting sensor, the moving direction and size of the floating body can be known.

On the other hand, in the first to fourth microvibration detecting devices of the present invention, the optical position of the superconductor (or magnetic circuit), which is a levitation body, is utilized with the accuracy of not more than the wavelength of light by utilizing the interference of light. Can be detected. And the first of the present invention
The second minute vibration control device controls the minute vibration of the levitation body by controlling the magnetic force of the magnetic circuit based on the detected optical position.

[0027]

Embodiments of the present invention and reference examples of related inventions will now be described with reference to the drawings.

FIG. 1 shows the first embodiment of the microvibration detecting device of the related invention.
FIG. 2 is a schematic diagram of a reference example, and FIG. 2 is a schematic explanatory view showing a superconducting sensor of the present reference example.

In FIG. 1, the magnetic circuit 11 is Sm-Co.
The magnet is processed into a ring shape with an outer diameter of 2 cm and an inner diameter of 0.6 cm, and it is fixedly installed on a stand or the like (not shown).
The superconductor 12 is an oxide superconductor (Y ₁ Ba ₂ Cu ₃ O _7-x superconductor) processed into a sphere having a diameter of 0.4 cm, and its critical temperature is about 90K. The superconductor 12 floats in the air where the magnetic field of the magnetic circuit 11 is formed by the Meissner effect in a non-contact state, and blocks the emitted light.

The light source 13 used as a source of electromagnetic waves (light) is composed of a laser diode. The cylindrical lens 14 corrects the shape of the light from the light source 13 from a circular shape to a linear shape, and irradiates the floating superconductor 12 with light by the Meissner effect. The superconducting sensor 15 is a detector for detecting light not blocked by the superconductor 12, and has Josephson junctions arranged at intervals of 10 μm.

The magnetic circuit 11, the superconductor 12 and the superconductor sensor 15 are cooled to a temperature below the critical temperature of the superconductor 12 as a cooling portion 16 by a cooling device (not shown). The magnetic circuit 11, the light source 13, the cylindrical lens, and the superconducting sensor 15 are fixed by the same structure so that their relative positions do not change.

The superconducting sensor 15 used in this reference example is shown below. That is, this superconducting sensor 15 is a superconducting line sensor in which Josephson junctions are connected in series and arranged one-dimensionally or two-dimensionally (x direction in FIG. 1 in this embodiment). The normal resistance values of the parts have different values.

In FIG. 2, the superconducting sensor 15 includes a Josephson junction 21 to 25, a load resistor R, and a DC voltage source E.
Of the 5 Josephson junctions is shown here to simplify the description. At this time, the normal resistance value of each Josephson junction 21 to 25 is r, 2r,
Set to 4r, 8r, 16r (Ω).

When no electromagnetic wave is incident, each of the Josephson junctions 21 to 25 has no resistance, but when an electromagnetic wave is incident, for example, if incident on the portion of the Josephson junction 21, rΩ, Josephson junction If the light enters the two parts 23 and 24, a resistance of 4r + 8r = 12r (Ω) will be generated.
By utilizing this, it is possible to uniquely determine which Josephson junction portion in the array the electromagnetic wave is incident on by measuring the voltage across the Josephson junction array.

That is, when electromagnetic waves are incident on the Josephson junctions 21 and 24, V = E (r + 8r) / (R + (r + 8R)) = (E · 9r) / (R + 9r), and R >> r If set, V = 9rE / R.
Since the coefficient "9" does not exist except for the combination of Josephson junctions 21 and 24, Josephson junctions 21 and 24
It can be seen that an electromagnetic wave is incident on.

A superconducting sensor generally has high sensitivity at a short wavelength. Further, as a means for setting the normal resistance value of the Josephson junction to a different value, for example, when a weak coupling type Josephson junction is adopted, a method of changing the width of the weak coupling portion, or a gate is provided in the weak coupling portion is used. There are a method of applying a voltage to this gate, a method of injecting quasi-particles into the gate portion, and the like. In any case, it can be realized by accurately forming the shape of the weakly coupled portion, but this may be performed by a normal patterning technique such as photolithography. Furthermore, in the case of the sensor of the present reference example, a point contact or a tunnel junction may be used although the process of the sensor of the present reference example is usually simpler when the sensor is manufactured.

Next, the operation of this reference example will be described with reference to FIG.

When the cooling portion 16 is cooled to about 77 K or less, the superconductor 12 floats as shown in FIG. 1 due to the Meissner effect. The light from the light source 13 to this superconductor 12 1
7 is linearly deformed by a cylindrical lens 14 and irradiated downward in the drawing.

In the absence of vibration, part of the light 17 is reflected by the superconductor 12 and does not reach the superconducting sensor 15, but the unreflected light 17 is detected by the superconducting sensor 15. The superconducting sensor 15 has an optical sensor consisting of multiple Josephson junctions arranged in the x direction.
When the superconductor 12 moves in the direction, the movement can be detected by the light 17 not reflected by the superconductor 12.

When vibration occurs, the magnetic circuit 11 is displaced by the vibration, but the superconductor 12 does not change its position immediately after the vibration due to inertia. This means that the relative positions of the superconductor 12 and the magnetic circuit 11 change due to vibration, so that the light 1 detected by the superconducting sensor 15
Vibration can be detected by changing the position of 7. The amplitude of vibration that can be detected is determined by the distance between the Josephson junctions arranged in the superconducting sensor 15. In this reference example, a line sensor with Josephson junctions arranged at intervals of 10 μm was used. Can be detected.

Next, a second reference example of the related invention will be described.

In FIG. 1, a light source 13 is a halogen lamp, and an optical system using a glass lens instead of the cylindrical lens 4 collimates the light from the halogen lamp into parallel rays. Furthermore, the superconducting sensor 15 is two-dimensional (x, y direction)
To array. With such a configuration, it is possible to detect minute vibrations in the two-dimensional directions, that is, the xy directions. Also,
Instead of the halogen lamp and the optical system, a gun oscillator capable of emitting parallel millimeter waves with a wavelength of about 0.5 mm may be used.

Next, a first embodiment of the present invention will be described.

FIG. 3 is a block diagram of the first embodiment of the microvibration detecting apparatus of the present invention. In this embodiment, the superconductor 32 is fixedly installed on a table or the like (not shown), and the magnet 31 floats. magnet
No. 31 is an Sm-Co magnet with an outer diameter of 10 mm and a thickness of 1 mm, which is machined into a ring shape with a 0.5 mm cylindrical hole at the center. The superconductor 32 is the superconductor of the first embodiment.
12 is an oxide superconductor made of the same material as 12 and has an outer diameter of 15 mm
The inner diameter was 5 mm and the thickness was 1 mm.

The superconductor 32 and the superconducting sensor 35 are cooled by a cooling device (not shown). The cooling temperature may be lower than the critical temperature of about 90 K of the superconductor 32 and the superconducting sensor 35, but it is preferably lowered to about 70 K.

The superconducting sensor 35 is a two-dimensional array of Josephson junction arrays having a size of 2 × 2 mm. The distance between the Josephson junctions is about 1 μm. It is emitted from the light source 133 through the lens 34,
From the movement of the light 37 passing through the center hole of the magnet 31 on the superconducting sensor 35, a minute change can be detected as in the second reference example of the related invention.

Next, a second embodiment of the present invention will be described.

FIG. 4 is a block diagram of the second embodiment of the microvibration detecting apparatus of the present invention.

In FIG. 4, the magnetic circuit 41 is equivalent to the magnetic circuit 11 of FIG. Superconductor 42 has a diameter of 3 m
m, 1 mm thick disc-shaped material made of the same material as the superconductor 12 of the first embodiment, except that a 0.1 mm thick Al thin plate is attached to the upper surface as a light reflecting plate. .

The superconducting sensor 45 is a two-dimensional optical sensor. In addition, a light source 43 and a cylindrical lens 44
And on each upper side (z direction side) of the superconducting sensor 45, a light source 43a, a cylindrical lens 44a and a superconducting sensor 45a, which are optical systems equivalent to these, are connected to the superconductor 4
It is arranged so that it faces one point on the upper surface of 2.

Although not shown in FIG. 4, the light source 43, the cylindrical lens 44 and the superconducting sensor are omitted.
The same optical system as the 45 is also arranged perpendicular to the paper surface. By cooling the superconductor 42 and the superconducting sensors 45, 45a in the same manner as in the first reference example of the related invention,
The superconductor 42 rises due to the Meissner effect.

Light source 43, cylindrical lens 44
And the superconducting sensor 45 detects displacements in the z and y directions, the optics arranged perpendicular to the paper indicate the z and x directions, and the light source 43a, the cylindrical lens 44a, and the superconducting sensor 45a detect the displacement. Conductor 4
The inclination of 2 from the horizontal direction (xy plane) is detected. By comprehensively analyzing the detection data from each optical system,
It is possible to detect minute vibrations in the dimensional direction at the same time.

Next, a third embodiment of the present invention will be described.

FIG. 5 is a block diagram of the third embodiment of the microvibration detecting device of the present invention.

In this embodiment, the superconductor 52 levitated by the magnetic circuit 51 is a rectangular parallelepiped of 1.2 × 1.2 × 1.0 mm,
A 100 μm pore is opened in the center of each surface. The pores may be processed by any method, but for example, they can be created by a method such as ion milling in which an argon ion laser beam is incident from the opposite surface to perform processing.

Each of the three light sources 53 and the cylindrical lenses 54 (only two of which are shown in FIG. 5) are x, y and z.
The superconductor 53 is irradiated with the light 57 from the three directions, and the corresponding three superconducting sensors 55 (only two are shown in FIG. 5).
Thus, the minute vibration in the three-dimensional direction can be measured as in the second embodiment. In FIG. 5, the optical system perpendicular to the paper surface is omitted.

In the present embodiment, since the pores through which light passes are not a perfect columnar shape but a conical shape, the stray light reflected by the conical surface blurs the optical image on the superconducting sensor 55. there is a possibility. Therefore, the transmitted light is corrected into parallel rays by the optical system 54b. Moreover, since the beam can be expanded 100 times by this optical system 54b, the resolution of the vibration amplitude is improved compared to the resolution of the superconducting sensor 55, which is 2 μm, and a minute vibration of 0.02 μm can be detected.

In the first and second reference examples of the related invention and the first to third embodiments of the present invention, Y ₁ Ba ₂ Cu ₃ O _7-x was used as the superconductor. The present invention is not limited to this, but includes metals such as Nb, alloy superconductors such as Nb ₃ Ti, Bi-Sr-Ca-Cu-O, and Tl-Sr-Ca-.
Any material that exhibits superconductivity, such as a Cu—O-based oxide superconductor, may be used. The shape and the number of superconductors used can be changed as required. That is, these are determined by the relative relationship with the magnet (magnetic circuit), and may be arranged so that the superconductor or the magnet is most easily floated by the Meissner effect.

Further, although the magnetic circuit has a ring shape in each of the embodiments, the shape and the number thereof are not particularly limited, and these may be determined in consideration of the gradient of the magnetic field. The magnetic circuit is not particularly limited as long as it can float a superconductor such as a permanent magnet, an electromagnet, or a superconducting magnet. Further, it goes without saying that the magnets are not limited to permanent magnets such as Sm-Co, and electromagnets and superconducting magnets can be used.

Any type of light (electromagnetic wave) generation source may be used as long as it has a straight traveling property. Since a superconducting sensor using Josephson junction is used, a millimeter-wave range transmission source such as a Gunn diode is also used. It is available. That is, the wavelength of the electromagnetic wave is not particularly limited as long as it is shorter than the long wavelength limit determined by the critical temperature of the superconductor line sensor, and for example, microwave or X-ray can be used. Also,
The electromagnetic waves need not be coherent waves, but are preferably as parallel as possible. Furthermore, the size of the superconducting sensor can be reduced by applying semiconductor processing technology, and its limit is the same as the microfabrication limit of semiconductors (note that the magnetic circuit, superconductor, and light source are specially limited. (See Kaihei 4-131716 publication).

Next, a fourth embodiment of the present invention will be described.

FIG. 6 is a schematic view of the essential portions of a fourth embodiment of the microvibration detecting device of the present invention, FIG. 7 is a perspective view showing the superconductor 61 and the magnetic circuit 62 of FIG. 6, and FIG. 8 is another magnetic circuit. FIG. 9 is a perspective view showing the magnetic circuit 82 of the embodiment, FIG. 9 is an explanatory diagram regarding an optical signal obtained by the fourth embodiment, and FIGS. 10 (a) and 10 (b) are explanatory diagrams regarding an electric signal obtained by the sixth embodiment. Is.

As shown in FIGS. 6 and 7, the superconductor 6
1 includes a plurality of reflecting plates 63 that are sufficiently flatly polished at predetermined positions on the upper surface thereof, and float in the air without contact due to the Meissner effect. The magnetic circuit 62 includes a plurality of reference reflectors 64 that are sufficiently flatly polished at predetermined positions on the upper surface of the magnetic circuit 62, and is an electrically controllable electromagnet that generates a magnetic force to levitate the superconductor 61.

The magnetic circuit 62 may be a permanent magnet that generates a strong magnetic field. However, since the magnetic circuit 62 serves as a reference for microvibration, it is fixed on a stable ground or floor without sufficient vibration. Must be present and must not change over time. Control circuit 75
Controls the electric power of the magnetic circuit 62.

The laser light source 65 generates a light beam having a coherent wavelength and a uniform wavelength. In this embodiment, a horizontally installed helium neon laser is used. A half mirror 66 tilted downward by 45 ° is installed in front of the laser light source 65 (light emitting direction) and above the reference reflector 64.

Further in front of the half mirror 66, a reflecting plate
Above 63 is a mirror that is also tilted 45 ° downwards.
70 are installed. Between the half mirror 66 and the reference reflector 64, a half mirror 67 tilted downward by 45 ° is installed like the half mirror 66. Between the mirror 70 and the reflector 63, a half mirror 71 tilted downward at an angle different from the 45 ° by a minute angle α is installed. Half mirrors 67 and 71 are installed at almost the same height.

An image forming lens 68 and an image pickup device 69 are provided on the right side of the half mirror 67 in the drawing (the traveling direction of light reflected from the half mirror 67 from below). The image pickup device 69 is connected to the signal processing device 73 via the preprocessing device 72, and the signal processing device 73 is connected to the arithmetic device 74. The arithmetic unit 74 is connected to the control unit 75.

The pre-processing device 72 performs image integration of the signal output from the image pickup device 69, controls the level so that the average value thereof becomes a set value, and removes unnecessary portions (edges) of the image. Perform preprocessing such as cutting and removing noise. The signal processing device 73 has a phase difference φ between the signals preprocessed by the preprocessing device 72 (see FIGS. 10 (a) and 10 (b)).
And outputs a signal indicating the position change of the reflector 63, that is, the superconductor 61 to the arithmetic unit 74. Arithmetic device 74
Converts the signal input from the signal processing device 73 into an appropriate physical quantity, such as the amplitude of vibration and the frequency.

The superconductor 61 has undergone rough alignment in advance with an accuracy of approximately one-half the wavelength of the light of the laser light source 65, and the relative position of the superconductor 61 and the magnetic circuit 62 has the above accuracy. Laser light source
Suppose there are no oscillations with amplitudes greater than half the wavelength of 65 light. For oscillations with an amplitude greater than one-half the wavelength of the light of the laser source 65, such a situation is sufficiently general, by using other means.

Next, vibration detection according to the fourth embodiment will be described.

The light beam emitted from the laser light source 65 is
It is split into two lights by the half mirror 66. The light beam 66a whose direction is changed by the half mirror 66 is reflected after being incident on the reference reflection plate 64 mounted on the magnetic circuit 62. The direction of the reflected light is changed by the half mirror 67, and after passing through the imaging lens 68, the imaging device 69
Image on. On the other hand, the rays that have passed through the half mirror 66
70a is a superconductor 61 after changing direction with mirror 70.
It is reflected by the reflection plate 63 of and enters the half mirror 71.

The half mirror 71 is 45 °, that is, 2
The light rays 66a and 70a of the book are inclined by a small angle α with respect to the angle at which the wavefronts of the light rays are parallel. Therefore, the wavefronts of the rays 66a and 70a intersect at a small angle α. Half mirror in this way
The light beam reflected by 71 passes through the imaging lens 68 and enters the imaging device 69.

Two light rays due to the inclination of the minute angle α
Since the spatial frequencies of 66a and 70a are effectively different, an interference pattern (striped pattern) is formed on the surface of the image pickup device 69 as shown in FIG. When the optical position of the superconductor 61 changes, this striped pattern moves in the direction of the arrow in FIG. 9 or in the opposite direction.

The optical signal thus obtained by the image pickup device 69 is transmitted to the signal processing device 73 as an electric signal through the preprocessing device 72. The obtained electric signal has a spatial distribution as shown in FIG. 10 (a). The wavelength λ of this spatial distribution is determined by the minute angle α. The phase difference φ in Fig. 10 (a) is the reference reflector 64 provided on the magnetic circuit 62 and the superconductor.
It is the difference in the optical position when viewed by the method of 2π from the reflection plate 63 provided on the surface of 61.

The signal processing device 73 calculates this phase difference φ as a time series at any time. That is, as shown in FIG. 10 (b), the time change of the phase difference φ is observed as a time change of the superconductor 61, that is, a minute vibration. Signal processor
The information on the minute vibration obtained at 73 is transmitted to the arithmetic unit 74, and the time series of the phase difference φ is converted into an appropriate physical quantity.

As shown in FIGS. 7 and 8, the superconductor 61,
By setting the same device at four points of the magnetic circuit 62 and performing the same measurement, the change in the inclination of the superconductor 61 can be known. For the sake of simplicity of explanation, those duplicated devices are not shown in FIG. 6, but their settings and the like can be easily guessed. In this case, the computing device 74
Comprehensively monitors the position information of each of the four points, and calculates information such as inclination.

Instead of the magnetic circuit 62 shown in FIG. 7, as shown in FIG. 8, a coil (not shown) is divided into some parts in the space direction, and each of them can be controlled independently.
If 82 is used, the superconductor 61 can be controlled by controlling its electric power.
Feedback can be applied to keep the super-horizontal. That is, as shown in FIG. 8, the magnetic circuit 82 is divided and controlled, and the magnetic intensity generated by each of the magnetic circuits 82 is controlled on the basis of the information on the detected microvibration to cause or attenuate the vibration. It can be controlled to In this case, the minute vibration can be freely controlled by feeding back to the control device 75 based on the physical quantity obtained by the arithmetic device 74 and changing each current value of the magnetic circuit 82 by the control device 75.

The microvibration in this embodiment can be applied to vibration having a very high frequency. That is,
The sufficiently high limit of the frequency of minute vibration is substantially the same as the state where there is no vibration, in other words, it corresponds to minute position detection or minute alignment.

Next, a fifth embodiment of the present invention will be described.

FIG. 11 shows the fifth embodiment of the microvibration detecting device of the present invention.
12 (a) and 12 (b) are schematic diagrams of the essential parts of the embodiment, and are explanatory diagrams relating to the electric signals obtained in the fifth embodiment.

The fifth embodiment is formed according to the heterodyne interferometry well known in the field of interferometric optical measurement (Mitsuo Takeda, Optics, Vol. 13, No. 1, pp. 55-65, Japan Optical Society (Applied Physics). Academic Society), published in February 1984). As shown in FIG. 11, the superconductor 111 is provided with a plurality of sufficiently flat polished reflectors 113 at predetermined positions on the upper surface thereof, and floats in the air without contact due to the Meissner effect.

The magnetic circuit 112 is provided with a plurality of reference reflectors 114 that are sufficiently flat and polished at predetermined positions on the upper surface thereof.
It is an electrically controllable electromagnet that generates a magnetic force that levitates the superconductor 111. The magnetic circuit 111 may be a permanent magnet that generates a strong magnetic field, but since the magnetic circuit 112 serves as a reference for microvibration, it may be fixed on a stable ground or floor without sufficient vibration. It is necessary that the change with time is sufficiently small. The superconductor 111 and the magnetic circuit 112 are the same as the superconductor 61 and the magnetic circuit 62 in FIG. 7. The control circuit 131 controls the electric power of the magnetic circuit 112.

The laser light source 115 emits a light beam having a coherent wavelength and a uniform wavelength. In this embodiment, a horizontally installed helium neon laser is used. In front of the laser light source 115 (direction of light emission)
A half mirror 116 tilted downward by 45 ° is installed above the reference reflector 114.

Further ahead of the half mirror 116 and above the reflecting plate 113, a mirror 126 which is also inclined downward by 45 ° is installed. Between the half mirror 116 and the reference reflector 114, as with the half mirror 116, 4
A half mirror 119 tilted downward by 5 ° is installed. Between the half mirror 116 and the half mirror 119, a half mirror 117 tilted upward by 45 ° is installed, which is opposite to the half mirror 119.

Between the mirror 126 and the reflector 113,
As with the mirror 126, a half mirror 124 tilted 45 ° downward is installed. Between the mirror 126 and the half mirror 124, a half mirror 123 tilted upward by 45 ° is installed, which is opposite to the half mirror 124.

Further, the mirror 126 and the half mirror 123
A frequency minute change device 122 is provided between them.
As the frequency minute change device 122, an ultrasonic Bragg cell method, a Zeeman effect method, or the like can be used (Mitsuo Takeda, Optics, Vol. 13, No. 1, pp. 55-65,
See Japan Optical Society (Japan Society of Applied Physics), published in February 1984).

The half mirror 117 is installed at a height slightly higher than that of the half mirror 123. Half mirror 119
Is installed slightly lower than the half mirror 124. Right side of the half mirrors 117 and 123 in the figure (direction of light reflected from the half mirrors 117 and 123 from above)
Is provided with a lens 125 and a light intensity sensing element 118. A lens 120 and a light intensity sensing element 121 are provided on the right side of the half mirrors 119 and 124 in the drawing (the traveling direction of light reflected from the half mirrors 119 and 124 from below).

The light intensity sensing elements 118 and 121 do not have to be image pickup elements, but may be any elements that can detect the intensity of light on the light receiving surface, such as photodiodes. The light intensity sensing elements 118 and 121 are connected to a signal processing device 129 via preprocessing devices 127 and 128, respectively, and the signal processing device 129 is connected to a computing device 130.

The arithmetic unit 130 is connected to the control unit 131. The pre-processing devices 127 and 128 are the light intensity sensing elements 11
Level control is performed so that the average value of the signals output from 8 and 121 becomes the set value, and preprocessing such as noise removal is performed. The signal processor 129 is a preprocessor 12
Phase difference φ of the signal preprocessed by 7 and 128 (Fig. 1
2 (a), (b)) and calculate the reflector 113 or superconductor.
The signal indicating the position change of 111 is output to the arithmetic unit 130. The arithmetic unit 130 converts the signal input from the signal processing unit 129 into an appropriate physical quantity, for example, amplitude of vibration, frequency, or the like.

The superconductor 111 has been rough-aligned in advance with an accuracy of about ½ of the wavelength of the light of the laser light source 115, and the relative position of the superconductor 111 and the magnetic circuit 112 has the above accuracy. Assuming that the range is fixed, it is assumed that there is no oscillation having an amplitude equal to or more than half the wavelength of the light of the laser light source 115. Such a situation is quite general, by using other means, for oscillations having an amplitude greater than one-half the wavelength of the light of the laser source 115.

Next, vibration detection according to the fifth embodiment will be described.

The light beam emitted from the laser light source 115 is split into two light beams by the half mirror 116. The light beam whose direction has been changed by the half mirror 116 is further divided into two by the half mirror 117, one of which passes through the half mirror 117 and the magnetic circuit 112 as it is.
The light is incident on the reference reflection plate 114 mounted on the other side, and the other light passes through the lens 125 as the reference light and passes through the light intensity sensing element 118.
Incident on.

The light incident on the reference reflection plate 114 mounted on the magnetic circuit 112 is reflected vertically by the reference reflection plate 114, the direction is changed by the half mirror 119, and the direction is changed minutely again by the lens 120. After that, the light enters the light intensity sensing element 121.

On the other hand, the frequency of the light beam transmitted through the half mirror 116 is finely changed by the frequency finely changing device 112 after the direction is changed by the mirror 126.
The light beam whose frequency is slightly changed by the frequency minute change device 112 is divided into two by the half mirror 123, and the light beam whose direction is changed by the half mirror 123 enters the light intensity sensing element 118 through the lens 125 as the reference light. To do.

The surface of the light intensity sensing element 118 interferes with the light beam whose direction is changed by the half mirror 117 and changes its interference fringes with time (becomes brighter or darker). The phase of this change is used as the reference phase. The light intensity sensing element 118 outputs a beat signal of cycle T.

On the other hand, the light beam that has passed through the half mirror 123 enters the reflecting plate 113 attached to the superconductor 111, is reflected there, is changed in direction by the half mirror 124, and is again changed in direction by the lens 120. It is incident on the light intensity sensing element 121 after being slightly changed. On the surface of the light intensity sensing element 101, the light from the half mirror 119 interferes with the light from the half mirror 124, and changes over time (becomes brighter or darker). Information on the optical position between the reference reflection plate 114 provided on the magnetic circuit 112 and the reflection plate 113 provided on the surface of the superconductor 111 is woven into the phase component of the temporal change.

The optical signals obtained by the light intensity sensing elements 118 and 121 in this manner are transmitted to the signal processing device 129 as electric signals through the preprocessing devices 127 and 128. In the obtained electric signal, as shown in FIG. 12 (a), the phase difference φ changes with time. This phase difference φ is a difference in optical position between the reference reflection plate 114 provided on the magnetic circuit 112 and the reflection plate 113 provided on the surface of the superconductor 111 when viewed by the 2π method.

The signal processing device 129 calculates the phase difference φ as a time series at any time. That is, as shown in FIG. 12 (b), the superconductor 111 changes with the time change of the phase difference φ.
Observed as a time change, that is, a minute vibration. The information on the microvibration obtained by the signal processing device 129 is calculated by the arithmetic device.
It is transmitted to 130 and the time series of phase difference φ is converted into an appropriate physical quantity.

In the present embodiment, the resolution of vibration is defined by the cycle T of the beat signal of the light intensity sensing element 118 serving as a reference. Therefore, in this embodiment, signals having a resolution lower than this resolution cannot be detected. However, because of the high spatial resolution that is a feature of the heterodyne method, highly sensitive measurement can be performed for vibration components that are sufficiently gentle with respect to the period T.

In the present embodiment, similar to the fourth embodiment, the same devices are set at the four points of the superconductor 111 and the magnetic circuit 112, and the same measurement is performed to perform the same measurement.
It is possible to know the change in the inclination of. In addition, if the coil is divided into some parts in the spatial direction and each is configured to be controlled independently, feedback can be applied to keep the superconductor 111 super-horizontal by controlling its electric power. The same can be applied to the fourth embodiment.

[0101]

As described above, according to the present invention, by utilizing the Meissner effect of a superconductor,
It has become possible to detect microscopic vibrations of two dimensions at the same time.
Further, in the present invention, since the superconductor or the magnet levitated by the Meissner effect does not come into contact with other parts constituting the detector, there is no performance deterioration due to mechanical fatigue.

Furthermore, in order to detect vibration optically, x,
The detection resolution in the y and z directions is also extremely excellent. For example, by inserting a light expansion mechanism between the superconductor and the detector, minute relative changes can be easily detected. In addition, since the present invention does not require a non-linear element such as a piezo element, it has excellent linearity.

Further, according to the present invention, minute vibrations can be detected with an accuracy of not more than the wavelength of light. It has become possible to detect the direction of microvibration. Therefore, it becomes possible to control a minute vibration, which is impossible with the conventional technology.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first reference example of a microvibration detection device of a related invention.

FIG. 2 is a schematic explanatory view showing a superconducting sensor of this embodiment.

FIG. 3 is a configuration diagram of a first embodiment of a microvibration detecting device of the present invention.

FIG. 4 is a configuration diagram of a second embodiment of the microvibration detecting device of the present invention.

FIG. 5 is a configuration diagram of a third embodiment of the microvibration detecting device of the present invention.

FIG. 6 is a schematic view of the essential portions of a fourth embodiment of the microvibration detection device of the present invention.

7 is a perspective view showing a superconductor 61 and a magnetic circuit 62 of FIG.

FIG. 8 is a perspective view showing a magnetic circuit 82 which is another mode of the magnetic circuit.

FIG. 9 is an explanatory diagram regarding an optical signal obtained by the fourth embodiment.

10 (a) and 10 (b) are explanatory diagrams regarding electric signals obtained in the fourth embodiment.

FIG. 11 is a schematic view of the essential portions of a fifth embodiment of the microvibration detection device of the present invention.

12 (a) and 12 (b) are explanatory diagrams regarding electric signals obtained in the fifth embodiment.

FIG. 13 is a perspective view showing a conventional example of a microvibration detection device.

[Explanation of symbols]

11, 41, 51, 62, 112: Magnetic circuit 12, 32, 42, 52, 61, 111: Superconductor 13, 33, 43, 53: Light source 14,44: Cylindrical lens 15, 35, 45, 55: Superconducting sensor 31: Magnet 34: Lens 65, 115: Laser light source 66, 67, 71, 116, 117, 119, 123, 124: Half mirror 70, 126: Mirror 68: Imaging lens 69: Imaging device 72, 127, 128: Pretreatment equipment 73, 129: Signal processing device 74, 130: arithmetic unit 75, 131: Control device

Continuation of front page (56) Reference JP-A-61-239164 (JP, A) JP-A-1-134266 (JP, A) JP-A-2-61509 (JP, A) JP-A-3-245580 (JP , A) JP-A-4-131716 (JP, A) JP-B-62-31281 (JP, B2) Patent 3217514 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01H 9 / 00

Claims (6)

(57) [Claims] 1. A microvibration detecting device having a superconductor and a magnetic circuit for generating a magnetic field for levitating the superconductor by the Meissner effect, and detecting the optical position of the levitated superconductor. A light source that emits coherent and uniform wavelength light, a reflector provided on the superconductor, a reference reflector provided on the magnetic circuit, and light from the light source on the reflector and the reference reflector, respectively. And an optical system that effectively modulates the frequency of one of the reflected light from the reflector and the reference reflector in the spatial direction, and an interference pattern between the modulated light and the unmodulated light. A microvibration detecting device, comprising: an image pickup means for picking up an image of the object; and a processing means for processing an output of the image pickup means and converting it into a signal indicating an optical position of the superconductor. 2. A microvibration detecting device having a superconductor and a magnet levitated by the Meissner effect of the superconductor and detecting the optical position of the levitated magnet, emits coherent and uniform-wavelength light. A light source, a reflector provided on the magnet, a reference reflector provided on the superconductor, an optical system for irradiating the reflector and the reference reflector with light from the light source, and the reflector And an optical system that effectively modulates one of the frequencies of the reflected light from the reference reflector in the spatial direction, an imaging unit that images the interference pattern between the modulated light and the unmodulated light, and the imaging unit. Processing means for processing the output of the above and converting it into a signal indicating the optical position of the magnet. 3. A microvibration detecting device having a superconductor and a magnetic circuit for generating a magnetic field for levitating the superconductor by the Meissner effect, and detecting the optical position of the levitated superconductor, A light source that emits coherent and uniform wavelength light, a reflector provided on the superconductor, a reference reflector provided on the magnetic circuit, and an optical system that modulates the frequency of light from the light source, An optical system for irradiating the reflection plate and the reference reflection plate with modulated light and non-modulated light, first and second light intensity sensing means for detecting the intensity of incident light, and the modulated light An optical system that causes unmodulated light to be incident on the first light intensity sensing unit and interferes with these lights, and reflected light from the reflector and the reference reflector is incident on the second light intensity sensing unit. Interfere with the light And a processing means for converting the outputs of the first and second light intensity sensing means into a light intensity distribution and converting the output to a signal indicating a position change of the superconductor. Vibration detector. 4. A microvibration detecting device having a superconductor and a magnet that levitates due to the Meissner effect of the superconductor, and emits coherent and uniform-wavelength light in a microvibration detecting device that detects the optical position of the levitated magnet. A light source, a reflector provided on the magnet, a reference reflector provided on the superconductor, an optical system for modulating the frequency of the light from the light source, and the reference plate and the reference reflector, respectively. System for irradiating the modulated light and the unmodulated light, first and second light intensity sensing means for detecting the intensity of the incident light, and the modulated light and the unmodulated light for the first light intensity An optical system for making these light beams interfere with each other by making them enter the sensing unit; and an optical system for making the light beams reflected by the reflector and the reference reflector plate enter the second light intensity receiving unit to interfere with these lights. 1st and 2nd light intensity Change the output of the sensing means to the intensity distribution of the light, the micro-vibration detecting apparatus characterized by having processing means for converting a signal indicating the position change of the superconductor. 5. A superconductor and a magnetic circuit capable of electrically controlling magnetic force for generating a magnetic field for levitating the superconductor by the Meissner effect, and controlling minute vibration of the levitated superconductor. In the microvibration control device, a light source that emits coherent light having a uniform wavelength, a reflector provided on the superconductor, a reference reflector provided on the magnetic circuit, the reflector and the reference reflector are provided. An optical system for irradiating light from the light source respectively, an optical system for effectively modulating the frequency of one of the reflected light from the reflector and the reference reflector in the spatial direction, and the modulated light An image pickup means for picking up an interference pattern with unmodulated light, a processing means for processing the output of the image pickup means and converting it into a signal indicating the position of the superconductor, and the magnetic field based on the output of the processing means. The magnetic force of the circuit Micro vibration control apparatus characterized by having a Gosuru control means. 6. A superconductor and a magnetic circuit capable of electrically controlling magnetic force for generating a magnetic field for levitating the superconductor by the Meissner effect, and detecting the optical position of the levitated superconductor. In the microvibration control device, a light source that emits coherent and uniform wavelength light, a reflector provided on the superconductor, a reference reflector provided on the magnetic circuit, and a frequency of light from the light source. An optical system for modulating light, an optical system for irradiating the reflecting plate and the reference reflecting plate with modulated light and unmodulated light, respectively, and first and second light intensity sensing means for detecting the intensity of incident light. An optical system that causes the modulated light and the unmodulated light to enter the first light intensity sensing means and causes the lights to interfere with each other; and the reflected light from the reflector and the reference reflector to the second light intensity. Incident on the sensing means An optical system for interfering these lights with each other, processing means for changing the outputs of the first and second light intensity sensing means into a light intensity distribution, and converting the output into a signal indicating a position change of the superconductor, A microvibration control device comprising: control means for controlling the magnetic force of the magnetic circuit based on the output of the processing means.