JP6095490B2 - Ultrasonic motor - Google Patents

Description

  The present invention relates to an ultrasonic motor.

  Conventionally, a microscope is often used for observing a fine structure such as a semiconductor or a biological sample. When observing these specimens with a microscope, the specimens are placed on the stage. At this time, in order to align the specimen to be observed, a stage (XY stage) that can move in two directions orthogonal to each other in a plane is used.

  The XY stage mainly includes a manual type and an electric type, and an electromagnetic motor is generally used as an actuator for the electric type stage. In recent years, it has also been proposed to use an ultrasonic motor capable of highly accurate positioning as an actuator for an electric stage.

  The ultrasonic motor moves the movable body by forming elliptical vibration in the vibrator (or stator) and bringing the vibrator on which the elliptical vibration is formed into contact with the sliding portion of the movable body (or slider). It is. For this reason, wear occurs in the sliding portion of the ultrasonic motor, but various methods for reducing the friction have been proposed.

  For example, in Non-Patent Document 1, in a rotary ultrasonic motor, slipping on a sliding surface is reduced by reducing the speed difference between the vibration speed of the vibrator on the sliding surface and the rotational speed of the movable body as much as possible. Techniques have been disclosed for reducing wear and consequently wear.

  FIG. 20A is a schematic diagram showing a change in velocity vector of a moving direction component of a movable body accompanying elliptical vibration of a conventional ultrasonic motor. FIG. 20B is a graph showing temporal changes in the magnitude of the velocity vector shown in FIG. 20A. In FIG. 20A, the velocity vector is schematically shown as a horizontal arrow, and in FIG. 20B, the left vector in FIG. 20A is represented as a positive value, and the right vector is represented as a negative value.

  As shown in FIG. 20B, a curve V1 representing a temporal change in the velocity vector magnitude (hereinafter referred to as “vibration velocity”) of the moving direction component of the movable body at the peripheral velocity of the elliptical vibration of the conventional ultrasonic motor is a sign. Draw a curve. On the other hand, the speed of the movable body does not change in a sine wave shape like the curve V1 of the temporal change of the vibration speed, and is almost constant as shown by the dotted line V2 regardless of the time.

  Comparing both the temporal change V1 and the temporal change V2 shown in FIG. 20B, it can be seen that there is a speed difference except at the intersection. This means that slippage due to the speed difference occurs between the vibrator and the movable body. As a rule of thumb, it can be seen that wear of the contact portion increases when slipping occurs, so it is considered that if the occurrence of slipping can be reduced as much as possible, the wear can be reduced.

  FIG. 20C is a graph when the temporal change in the magnitude of the velocity vector shown in FIG. 20B is changed from a sine wave to a rectangular wave. In Non-Patent Document 1, as one method for reducing wear by reducing slippage, it is devised to change the temporal change in vibration speed from a sine wave to a rectangular wave as shown in FIG. 20C. . In FIG. 20C, the temporal change in the vibration speed converted into a rectangular wave is shown as V3.

ここで、ｖ（ｔ）は矩形波、ｖ_０は矩形波の振幅、ｎは整数である。 It is known that a rectangular wave is expressed as the following formula (1) when it is decomposed into a Fourier series.

Here, v (t) is a rectangular wave, _{v 0} is the amplitude of the square wave, n is an integer.

  From the above equation (1), in order to change the temporal change of the vibration speed into a rectangular wave as shown in FIG. 20C, the vibration speed has a frequency of (2n + 1) times and the vibration speed amplitude is 1 / It can be seen that it is sufficient to add vibrations that are (2n + 1) times larger. In Non-Patent Document 1, the vibrator is configured so that the torsional vibration of the third-order mode has a frequency three times that of the torsional vibration of the first-order mode and the amplitude of the vibration speed is 1/3 times.

  Also, for example, Patent Document 1 proposes a linear ultrasonic motor that forms elliptical vibration using longitudinal vibration (longitudinal vibration in primary mode) and bending vibration (flexural vibration in secondary mode). Yes. Similarly to the ultrasonic motor described in Non-Patent Document 1, for this ultrasonic motor, harmonics having an odd multiple of frequency are applied to vibration in the moving direction of the moving table, that is, longitudinal vibration in the primary mode. If the vibration velocity waveform is made closer to a rectangular wave, the effect of reducing wear should be expected.

JP 2008-136318 A

Takaaki ISHII, Hisanori TAKAHASHI, Kentaro NAKAMURA and Sadayuki UEHA, “A Low-Wear Driving Method of Ultrasonic Motors”, Jpn.J.Appl.Phys., Vol.38 (1999) pp.3338-3341 Part 1, No.5B , May 1999

  In order to bring the vibration velocity waveform closer to a rectangular wave as shown in FIG. 20C, the ratio of the resonance frequency between the first-order mode and the third-order mode in the longitudinal vibration needs to be 1: 3.

  In the ultrasonic motor described in Patent Document 1, as a result of calculation and measurement by FEM (Finite Element Method), the ratio of the resonance frequency between the primary mode and the tertiary mode in longitudinal vibration is approximately 1: The resonance frequency of the third-order mode of longitudinal vibration was slightly low. Further, regarding the ratio of the resonance frequency between the first-order mode and the fifth-order mode in the longitudinal vibration, when the same calculation and measurement were performed, the ratio was slightly different from 1: 5.

  Thus, in the ultrasonic motor described in Patent Document 1, the ratio of the resonance frequency between the first-order mode and the n-th mode (where n is an odd number of 3 or more) in longitudinal vibration is just 1: n. It is slightly shifted. Therefore, with the technique described in Patent Document 1, it is difficult to reduce the wear of the sliding surface by bringing the waveform of the vibration speed closer to a rectangular wave.

  This invention is made | formed in view of the above, Comprising: It aims at providing the ultrasonic motor which can reduce the abrasion of a sliding part.

  In order to solve the above-described problems and achieve the object, the ultrasonic motor according to the present invention includes a first and a second that excite either one of longitudinal vibration and bending vibration included in the ultrasonic elliptical vibration. An ultrasonic vibrator having a piezoelectric element electrode, a first frequency that matches a mechanical resonance frequency of the ultrasonic vibrator, and a second frequency having an odd multiple of 3 or more with respect to the first frequency A first frequency signal generating unit that generates a first frequency signal including a second frequency signal that generates a second frequency signal including a third frequency that matches the mechanical resonance frequency of the ultrasonic transducer A first electrical resonance circuit having a resonance frequency matching the second frequency is formed between the signal generation unit and the first piezoelectric element electrode and connected to the first piezoelectric element electrode. A first electrical resonance having a first inductance; Characterized in that it comprises a road forming unit.

  The ultrasonic motor according to the present invention is the ultrasonic motor according to the fourth aspect, wherein the second frequency signal generated by the second frequency signal generator has an odd multiple of 3 or more with respect to the third frequency. And a second electrical resonance circuit that is connected to the second piezoelectric element electrode and has a resonance frequency that coincides with the fourth frequency with the second piezoelectric element electrode. And a second electrical resonance circuit forming unit having a second inductance.

  The ultrasonic motor according to the present invention is the ultrasonic motor according to the present invention, wherein the ultrasonic elliptical vibration matches the mechanical resonance frequency of the longitudinal vibration of the ultrasonic vibrator with the mechanical resonance frequency of the bending vibration. It is formed by exciting at a frequency that matches the frequency and providing a phase difference between the longitudinal vibration and the bending vibration.

  The ultrasonic motor according to the present invention is the ultrasonic motor according to the present invention, wherein the first electrical resonance circuit forming unit includes the inductor having the first inductance connected in series to the first piezoelectric element electrode. It is characterized by.

  The ultrasonic motor according to the present invention is the ultrasonic motor according to the present invention, wherein the first electrical resonance circuit forming unit is connected in series to the first piezoelectric element electrode, and the inductor having the first inductance, And a capacitor connected in parallel or in series with the first piezoelectric element electrode.

  In the ultrasonic motor according to the present invention, in the above invention, the second electrical resonance circuit forming unit includes the inductor having the second inductance connected in series to the second piezoelectric element electrode. It is characterized by.

  The ultrasonic motor according to the present invention is the ultrasonic motor according to the above invention, wherein the second electrical resonance circuit forming unit is connected in series to the second piezoelectric element electrode, and the inductor having the second inductance, And a capacitor connected in parallel or in series with the second piezoelectric element electrode.

  The ultrasonic motor according to the present invention is characterized in that, in the above invention, the phase difference and amplitude ratio of the frequency component of the second frequency can be adjusted with respect to the frequency component of the first frequency.

  The ultrasonic motor according to the present invention is characterized in that, in the above invention, the phase difference and amplitude ratio of the frequency component of the fourth frequency can be adjusted with respect to the frequency component of the third frequency.

  ADVANTAGE OF THE INVENTION According to this invention, the ultrasonic motor which can reduce the abrasion of a sliding part can be provided.

FIG. 1 is a diagram schematically showing an overall configuration and an internal configuration of an inverted microscope according to Embodiment 1 of the present invention. FIG. 2 is a diagram showing an overall configuration of the electric stage according to the first embodiment of the present invention. FIG. 3 is a circuit diagram showing the configuration of the drive unit and the ultrasonic transducer according to the first embodiment of the present invention. FIG. 4A is a schematic diagram showing four types of plate-like piezoelectric bodies constituting the ultrasonic transducer. FIG. 4B is a schematic diagram showing four types of plate-like piezoelectric bodies constituting the ultrasonic transducer. FIG. 4C is a schematic diagram showing four types of plate-like piezoelectric bodies constituting the ultrasonic transducer. FIG. 4D is a schematic diagram showing four types of plate-like piezoelectric bodies constituting the ultrasonic transducer. FIG. 5 is a schematic diagram showing a lamination example of four types of plate-like piezoelectric bodies that constitute the ultrasonic transducer. FIG. 6 is a schematic diagram showing an example of electrical connection of the ultrasonic transducer shown in FIG. FIG. 7 is a diagram for explaining a frequency signal generated by the frequency signal generator according to the first embodiment of the present invention. FIG. 8 is a graph showing temporal changes in the vibration speed of the longitudinal vibration and the transverse vibration of the ultrasonic transducer according to the first embodiment of the present invention. FIG. 9 is a graph showing a temporal change in vibration speed when the longitudinal vibration and the lateral vibration shown in FIG. 8 are combined. FIG. 10A is a perspective view showing the shape of the ultrasonic transducer according to the second embodiment. FIG. 10B is a plan view for explaining steps of the ultrasonic transducer according to the second embodiment. FIG. 11 is a conceptual diagram illustrating the resonance vibration of the longitudinal first-order mode related to the length L1 and the resonance vibration of the longitudinal third-order mode related to the length L2 in the ultrasonic transducer according to the second embodiment. FIG. 12 is a circuit diagram showing the configuration of the drive unit and the ultrasonic transducer according to the second embodiment of the present invention. FIG. 13A is a graph showing an analog waveform of a signal recorded in the first waveform memory. FIG. 13B is a graph showing a signal obtained by synthesizing a plurality of signals shown in FIG. 13A. FIG. 14A is a graph showing an analog waveform of a signal recorded in the second waveform memory. FIG. 14B is a graph showing a signal obtained by synthesizing a plurality of signals shown in FIG. 14A. FIG. 15 is a graph showing temporal changes in the vibration speed of the ultrasonic transducer according to the second embodiment of the present invention. FIG. 16 is a circuit diagram showing the configuration of the drive unit and the ultrasonic transducer according to the third embodiment of the present invention. FIG. 17A is a graph for explaining a first pulse waveform generated by the PWM signal generator. FIG. 17B is a graph for explaining a first pulse waveform generated by the PWM signal generator. FIG. 17C is a graph for explaining a first pulse waveform generated by the PWM signal generator. FIG. 18A is a graph for explaining a second pulse waveform generated by the PWM signal generator. FIG. 18B is a graph for explaining a second pulse waveform generated by the PWM signal generator. FIG. 18C is a graph for explaining a second pulse waveform generated by the PWM signal generator. FIG. 19 is a circuit diagram showing a configuration of a drive unit and an ultrasonic transducer according to a modification of the third embodiment of the present invention. FIG. 20A is a schematic diagram showing a change in velocity vector of a moving direction component of a movable body accompanying elliptical vibration of a conventional ultrasonic motor. FIG. 20B is a graph showing temporal changes in the magnitude of the velocity vector shown in FIG. 20A. FIG. 20C is a graph when the temporal change in the magnitude of the velocity vector shown in FIG. 20B is changed from a sine wave to a rectangular wave.

  In the following description, an inverted microscope using a linear drive type ultrasonic actuator (ultrasonic motor) will be described as a mode for carrying out the present invention (hereinafter referred to as “embodiment”). Moreover, this invention is not limited by this embodiment. Furthermore, the same code | symbol is attached | subjected to the same part in description of drawing. Furthermore, the drawings are schematic, and it should be noted that the relationship between the thickness and width of each member, the ratio of each member, and the like are different from the actual ones. Moreover, the part from which a mutual dimension and ratio differ also in between drawings.

(Embodiment 1)
FIG. 1 is a diagram schematically showing an overall configuration and an internal configuration of an inverted microscope according to Embodiment 1 of the present invention. The inverted microscope 1 shown in FIG. 1 includes an electric stage 2 on which a specimen Sp is placed, a main body 3 that supports the electric stage 2, and a specimen Sp that is positioned above the main body 3 and placed on the electric stage 2. And a control device 5 that controls the electric stage 2.

  An objective lens 6 is attached to the main body 3 close to the lower side of the electric stage 2. In addition, a reflection mirror 7 that reflects light that has passed through the objective lens 6 and an imaging optical system 8 that forms an image of light reflected by the reflection mirror 7 are provided inside the main body 3. On the optical path of the imaging optical system 8, an eyepiece 9 that collects the light imaged by the imaging optical system 8 is attached to the lens barrel 10 of the main body 3.

  The transmitted illumination unit 4 includes an arm 12 extending from the upper end of the transmitted illumination support column 11 in a direction orthogonal to the direction in which the transmitted illumination support column 11 extends, and a light source provided on the opposite side of the upper end of the transmitted illumination support column 11 from the side on which the arm 12 extends. 13, a lamp house 14 that is attached near the upper end of the transmission illumination column 11 and accommodates the light source 13, and is positioned above the electric stage 2, and the illumination light emitted from the light source 13 is collected and connected to the sample Sp. It has a condenser lens 15 for imaging, and a condenser unit 16 that is attached to the central portion of the transmission illumination column 11 and holds the condenser lens 15. Further, inside the arm 12, a collector lens 17 that collects light emitted from the light source 13, a field stop 18 that can adjust the amount of light that has passed through the collector lens 17, and light that has passed through the field stop 18. And a reflection mirror 19 that is bent in the direction of the optical axis N1 of the condenser lens 15 (a direction orthogonal to the incident direction).

  FIG. 2 is a diagram showing an overall configuration of the electric stage according to the first embodiment of the present invention. In the drawing, the X direction (first direction) is an arbitrary direction in a plane parallel to the upper surface of the electric stage 2, and the Y direction (second direction) is X in a plane parallel to the upper surface of the electric stage 2. It is a direction orthogonal to the direction (first direction). In the first embodiment of the present invention, an electric movement mode for moving the electric stage 2 to an arbitrary position in the XY direction or stopping at an arbitrary position by electric driving, and an electric stage 2 to an arbitrary position in the XY direction manually. And a manual movement mode for movement.

  The electric stage 2 includes, for example, a moving part (stage) 22 composed of a first member (base part) 21, a second member (X direction moving part) 22x, and a third member (Y direction moving part) 22y, and an X direction moving part 22x. And guide rails 23x and 23y for guiding the movement of the Y-direction moving unit 22y, an ultrasonic actuator 24 (24x and 24y), an encoder (displacement sensor) 25 (25x and 25y), and a control device 5, respectively. . In addition, the opening 26 according to the optical axis N1 (FIG. 1) is formed in the base 21, X direction moving part 22x, and Y direction moving part 22y. In addition, in this specification, when describing with the moving part 22, it points out any one or both of the 2nd member (X direction moving part) 22x and the 3rd member (Y direction moving part) 22y.

  The base 21 is fixed to the inverted microscope 1 shown in FIG. 1, and, for example, a ball circulation type guide rail 23x is attached to the upper surface along the X direction. Further, on the base 21, an ultrasonic actuator 24x for moving the X-direction moving unit 22x and a displacement amount of the X-direction moving unit 22x (relative positional relationship between the base 21 and the X-direction moving unit 22x) are detected. An encoder 25x is fixed.

  The X-direction moving unit 22x is attached on the base 21 so as to be capable of reciprocating in the X direction (first direction) along the guide rail 23x. A sliding member 27x made of a hard material such as ceramics is provided on a side surface parallel to the X direction of the X direction moving portion 22x. As the material of the sliding member 27x, for example, alumina, zirconia, stabilized zirconia and the like are suitable.

  In addition, a scale 28x is provided on a side surface parallel to the X direction of the X direction moving unit 22x. In FIG. 2, one of the sliding member 27x and the scale 28x is provided on the opposite side surface, but may be provided on the same side surface.

  The encoder 25x on the base portion 21 detects a displacement amount of the X-direction moving portion 22x by detecting a pattern such as a scale provided on the scale 28x, and determines the relative position of the X-direction moving portion 22x with respect to the base portion 21. The represented coordinate position information is supplied to the detection unit 54 in the control device 5.

  The ultrasonic actuator 24 x is attached to the base 21 and includes an ultrasonic transducer 30 and a holding mechanism 29. The ultrasonic transducer 30 is provided with transducers 30a and 30b on the side surface facing the moving unit 22x. The vibrators 30a and 30b are in contact with and pressed by the sliding member 27x provided on the side surface of the moving part 22x. The vibrators 30a and 30b are made of, for example, a material containing a resin having a relatively small friction coefficient including reinforcing fibers as a base material. The ultrasonic actuator 24 x is driven by a drive signal (bending vibration signal, longitudinal vibration signal) supplied from the drive unit 53 in the control device 5, and moves the X-direction moving unit 22 x relative to the base 21.

  Further, for example, a ball circulation type guide rail 23y is attached to the upper surface of the X-direction moving unit 22x along the Y direction. Further, an ultrasonic actuator 24y for moving the Y-direction moving unit 22y on the X-direction moving unit 22x and a displacement amount of the Y-direction moving unit 22y (relative to the X-direction moving unit 22x and the Y-direction moving unit 22y). The encoder 25y for detecting the target positional relationship) is fixed.

  The Y-direction moving part 22y is mounted on the X-direction moving part 22x so as to be able to reciprocate in the Y direction (second direction) along the guide rail 23y. For example, a sliding member 27y made of a hard material such as ceramic is provided on a side surface parallel to the Y direction of the Y direction moving portion 22y. As the material of the sliding member 27y, for example, alumina, zirconia, stabilized zirconia, and the like are suitable.

  A scale 28y is provided on the side surface of the Y-direction moving unit 22y that is parallel to the Y direction. In FIG. 2, one of the sliding member 27y and the scale 28y is provided on the opposite side surface, but may be provided on the same side surface.

  The encoder 25y provided on the X-direction moving unit 22x detects the displacement of the Y-direction moving unit 22y by detecting the pattern of the scale 28y, and the Y-direction moving unit 22y is relative to the X-direction moving unit 22x. Position information representing the target position is supplied to the detection unit 54 in the control device 5.

  The ultrasonic actuator 24 y is attached to the X-direction moving unit 22 x and includes an ultrasonic transducer 30 and a holding mechanism 29. The ultrasonic transducer 30 is provided with transducers 30a and 30b on the side surface facing the moving portion 22y. The vibrators 30a and 30b are in contact with and pressed by a sliding member 27y provided on the side surface of the moving part 22y. The vibrators 30a and 30b are made of, for example, a material containing a resin having a relatively small friction coefficient including reinforcing fibers as a base material. The ultrasonic actuator 24y is driven by a drive signal (bending vibration signal, longitudinal vibration signal) supplied from the drive unit 53 in the control device 5, and moves the Y-direction moving unit 22y relative to the X-direction moving unit 22x. Move.

  As described above, the X direction moving unit 22x reciprocates in the first direction (X direction) with respect to the base 21, and the Y direction moving unit 22y reciprocates in the second direction (Y direction) with respect to the X direction moving unit 22x. It is mounted movably. Therefore, the Y-direction moving unit 22y can move to an arbitrary position on the XY plane with respect to the base unit 21.

  The control device 5 includes, for example, a control unit 51, an instruction unit 52, a drive unit 53, and a detection unit 54, and performs drive control of the electric stage 2. The instruction unit 52 is an input means for inputting start and stop of movement of the electric stage 2 and a moving direction. The user operates the instruction unit 52 to electrically move the electric stage 2 to an arbitrary position. In addition to the moving direction, a moving speed or the like may be designated. The instruction unit 52 includes, for example, a direction instruction switch and a joystick. As long as the instruction | indication part 52 can instruct | indicate the moving direction of the movement part 22 at least, what kind of thing may be sufficient as it. For example, a software switch displayed on a touch panel or a display screen may be used. Alternatively, a plurality of movement instructions may be recorded in advance as sequence data, and the recorded sequence data may be reproduced to automatically perform movement instructions. In the present embodiment, the end of movement is determined by interruption of input of the movement instruction. However, a switch or the like for instructing the end of movement may be provided separately.

  When a movement instruction is input from the instruction unit 52, the control unit 51 controls the drive unit 53 to output a drive signal corresponding to the movement instruction. For example, when the electric stage 2 is moved in a predetermined direction, the drive unit 53 is controlled so as to supply a drive signal (bending vibration signal, longitudinal vibration signal) to the ultrasonic actuator 24 (24x and 24y). . When the electric stage 2 is stationary, the drive unit 53 is controlled so as to stop the supply of drive signals (flexural vibration signal, longitudinal vibration signal).

  The detection unit 54 reads the positional information from the encoder 25 (25x and 25y), and determines the relative positional relationship between the base unit 21 and the X direction moving unit 22x, and the relative positional relationship between the X direction moving unit 22x and the Y direction moving unit 22y. The respective position coordinates of the X direction moving unit 22x and the Y direction moving unit 22y are detected. Information on the detected position coordinates is sent to the control unit 51. The detection unit 54 can also detect the movement speed, acceleration, and the like of the X-direction moving unit 22x and the Y-direction moving unit 22y. Moreover, you may provide the pressure sensor which detects the pressure applied to X direction moving part 22x and Y direction moving part 22y.

  FIG. 3 is a circuit diagram showing the configuration of the drive unit and the ultrasonic transducer according to the first embodiment of the present invention.

  The ultrasonic transducer 30 is, for example, a piezoelectric element having a laminated structure, a first piezoelectric element electrode 31 that excites longitudinal vibration (primary mode longitudinal vibration), and bending vibration (secondary mode bending vibration). And a second piezoelectric element electrode 32.

  The drive unit 53 includes circuits connected to the first piezoelectric element electrode 31 and the second piezoelectric element electrode 32, respectively.

  An inductor 33 whose inductance can be finely adjusted is connected in series to the first piezoelectric element electrode 31. The other end of the inductor 33 is connected to the output of the power amplifier 35. The outputs of the first frequency signal generator 41 and the second frequency signal generator 42 are connected in parallel to the input of the power amplifier 35 via resistors 37 and 38, respectively.

  An inductor 34 whose inductance can be finely adjusted is connected in series to the second piezoelectric element electrode 32. The other end of the inductor 34 is connected to the output of the power amplifier 36. The outputs of the third frequency signal generator 43 and the fourth frequency signal generator 44 are connected in parallel to the input of the power amplifier 36 via resistors 39 and 40, respectively.

  A first frequency signal generator 41, a second frequency signal generator 42, a third frequency signal generator 43, a fourth frequency signal generator 44, resistors 37, 38, 39 and 15; Functions as a frequency signal generating means.

  4A to 4D are schematic views showing four types of plate-like piezoelectric bodies constituting the ultrasonic transducer. In the figure, the symbols “+” (plus) and “−” (minus) indicate the polarization directions of the corresponding polarization parts, and the polarization directions are reversed between “+” and “−”. Show.

  The plate-like piezoelectric body 61 shown in FIG. 4A is an inert piezoelectric body, and no electrode is formed. The plate-like piezoelectric body 62 shown in FIG. 4B is provided with driving bending vibration electrodes 63a, 63b, 63c, and 63d and a longitudinal vibration detection electrode 64, which are electrically connected to the drive unit 53, respectively. Lead patterns 70a, 70b, 70c, and 70d for connection are provided. A lead pattern 71 is connected to the longitudinal vibration detection electrode 64. In the plate-like piezoelectric body 65 shown in FIG. 4C, driving bending vibration electrodes 66a, 66b, 66c, and 66d and a driving longitudinal vibration electrode 67 are formed. Lead patterns 72a, 72b, 72c, 72d and 73 for connection are provided. A plate-like piezoelectric body 68 shown in FIG. 4D is a piezoelectric body on which a GND (ground) electrode 69 is formed, and lead patterns 74 a and 74 b for electrical connection with the drive unit 53 are provided.

  FIG. 5 is a schematic diagram showing a lamination example of four types of plate-like piezoelectric bodies that constitute the ultrasonic transducer. As shown in FIG. 5, the ultrasonic transducer 30 is configured by laminating four types of plate-like piezoelectric bodies 61, 62, 65 and 68 in a predetermined order. In the example shown in FIG. 5, one plate-like piezoelectric body 61, two plate-like piezoelectric bodies 62, two plate-like piezoelectric bodies 65, and three plate-like piezoelectric bodies 68 are used. The bodies 62, 68, 65, 68, 65, 68, 62, 61 are laminated in this order. Lead patterns 70 a to 74 b are exposed on the side surfaces of the ultrasonic transducer 30.

  The number of the plate-like piezoelectric bodies constituting the ultrasonic transducer 30 is not limited to this, and the plate-like piezoelectric bodies 62 or the plate-like piezoelectric bodies 65 and the plate-like piezoelectric bodies 68 are alternately stacked, and the outermost layer is formed. If the plate-like piezoelectric body 61 is used, the number of sheets can be arbitrarily changed as necessary. Further, the lowermost layer may be a plate-like piezoelectric body 61.

  FIG. 6 is a schematic diagram showing an example of electrical connection of the ultrasonic transducer shown in FIG. In this example, the lead patterns 70 a to 74 b of the plate-like piezoelectric bodies 62, 68 and 65 exposed from the side surface of the ultrasonic transducer 30 are electrically connected by electrode patterns 75 to 82, respectively.

  The electrode pattern 75 electrically connects the lead patterns 70b and 72b of all the plate-like piezoelectric bodies 62 and 65, and electrically connects all the driving bending vibration electrodes 63b and 66b.

  The electrode pattern 76 electrically connects the lead patterns 71 of all the plate-like piezoelectric bodies 62 and electrically connects all the longitudinal vibration detection electrodes 64.

  The electrode pattern 77 electrically connects the lead patterns 74 a of all the plate-like piezoelectric bodies 68. The electrode pattern 81 electrically connects the lead patterns 74b of all the plate-like piezoelectric bodies 68. Thereby, all the GND electrodes 69 are electrically connected.

  The electrode pattern 78 electrically connects the lead patterns 70c and 72c of all the plate-like piezoelectric bodies 62 and 65, and electrically connects all the driving bending vibration electrodes 63c and 66c.

  The electrode pattern 79 electrically connects the lead patterns 70a and 72a of all the plate-like piezoelectric bodies 62 and 65, and electrically connects all the driving bending vibration electrodes 63a and 66a.

  The electrode pattern 80 electrically connects the lead patterns 73 of all the plate-like piezoelectric bodies 65 and electrically connects all the driving longitudinal vibration electrodes 67.

  The electrode pattern 82 electrically connects the lead patterns 70d and 72d of all the plate-like piezoelectric bodies 62 and 65, and electrically connects all the driving bending vibration electrodes 63d and 66d.

  The electrode patterns 80, 77, and 81 function as the first piezoelectric element electrode 31 that excites longitudinal vibration (longitudinal vibration in the first mode), and the electrode patterns 75, 78, 79, 82, 77, and 81 are flexural vibrations. It functions as the second piezoelectric element electrode 32 that excites (second-order bending vibration). The electrode pattern 80 can be used for the purpose of detecting the longitudinal vibration of the ultrasonic transducer 30 and controlling the voltage waveform applied to the first piezoelectric element electrode 31 as necessary.

  The dimensions of the ultrasonic vibrator 30 are adjusted so that the mechanical resonance frequencies of the longitudinal vibration and the bending vibration are aligned, and the first piezoelectric element electrode 31 and the second piezoelectric element electrode 32 are aligned with the machine of the ultrasonic vibrator 30. A voltage having a frequency that matches the resonance frequency is applied, and the phase difference between the voltages of the first piezoelectric element electrode 31 and the second piezoelectric element electrode 32 is adjusted, so that there is a phase difference between the longitudinal vibration and the bending vibration. To form an elliptical vibration.

  FIG. 7 is a diagram for explaining a frequency signal generated by the frequency signal generator according to the first embodiment of the present invention. FIG. 8 is a graph showing temporal changes in the vibration speed of the longitudinal vibration and the transverse vibration of the ultrasonic transducer according to the first embodiment of the present invention. FIG. 9 is a graph showing a temporal change in vibration speed when the longitudinal vibration and the lateral vibration shown in FIG. 8 are combined. Hereinafter, the operation of the ultrasonic transducer 30 according to the first embodiment of the present invention will be described with reference to FIG. 3 and FIGS.

The frequency ω ₁ of the first frequency signal FS 1 generated by the first frequency signal generator 41 and the third frequency signal FS 3 generated by the third frequency signal generator 43 is the longitudinal vibration and bending of the ultrasonic transducer 30. The first frequency signal FS1 and the third frequency signal FS3 coincide with the resonance frequency of the vibration, and the phase difference between them can be changed.

The second frequency signal FS2 to the second frequency signal generator 42 generates a first frequency signal generator 41 first three times the frequency of the frequency omega ₁ of the frequency signal FS1 which occurs omega _{2 (omega 2} = 3ω ₁ ), and the amplitude and phase difference of the second frequency signal FS2 can be changed with respect to the first frequency signal FS1.

The fourth frequency signal FS4 generated by the fourth frequency signal generator 44 is a frequency ω ₂ (ω _{2) that} is three times the frequency ω ₁ of the third frequency signal FS3 generated by the third frequency signal generator 43. = 3ω ₁ ), and the amplitude and phase difference of the fourth frequency signal FS4 can be changed with respect to the third frequency signal FS3.

The first piezoelectric element electrode 31 has an electrostatic capacity (braking capacity) C _dA derived from the structure. The electrical resonant frequency due to the inductance _{L A} of the damping capacity _{C dA} and the inductor 33 is consistent with the frequency omega ₂ of the second frequency signal FS2. That is, the following expression (2) is satisfied. In this specification, “matching” includes not only the case where two frequencies completely match, but also the case where, for example, one frequency is within a range of ± 5% with respect to the other frequency.
L _A ≈1 / (ω ₂ ² · C _dA ) = 1 / {(3ω ₁ ) ² · C _dA } (2)

Similarly, the second piezoelectric element electrode 32 has a capacitance (braking capacity) C _dB derived from its structure. The electrical resonant frequency due to the inductance _{L B} of damping capacity _{C dB} and the inductor 34 is consistent with the frequency omega ₂ of the fourth frequency signal FS4. That is, the following expression (3) is satisfied.
L _B ≈1 / (ω ₂ ² · C _dB ) = 1 / {(3ω ₁ ) ² · C _dB } (3)

  A first electrical resonance circuit is formed between the first piezoelectric element electrode 31 and the inductor 33. The first electrical resonance circuit has a resonance frequency that matches the second frequency that is an odd multiple of 3 or more with respect to the first frequency that matches the mechanical resonance frequency of the longitudinal vibration of the ultrasonic transducer 30. A second electrical resonance circuit is formed between the second piezoelectric element electrode 32 and the inductor 34. The second electrical resonance circuit has a resonance frequency that matches the second frequency that is an odd multiple of 3 or more with respect to the first frequency that matches the mechanical resonance frequency of the bending vibration of the ultrasonic transducer 30.

The power amplifiers 35 and 11 amplify the power of the frequency signals having the frequencies ω ₁ and ω ₂ , and in addition to the analog amplifiers, digital amplifiers using PWM (pulse width modulation), PDM (pulse density modulation) Etc.

The first frequency signal generator 41 outputs a first frequency signal FS1 having a frequency ω ₁ that matches the mechanical resonance frequency of the longitudinal vibration of the ultrasonic transducer 30, and simultaneously the second frequency signal generator 42. is amplified to the power oscillation is obtained needed to output the second frequency signal FS2 of 3 times the frequency omega ₂ of the first frequency signal generator 41, driving the ultrasonic transducer 30 by the power amplifier 35 To do. In order to cope with the variation in the electrical resonance frequency due to variations in the production of the braking capacitance C _dA of the first piezoelectric element electrode 31, the inductor 33 has the capacitance C _dA of the first piezoelectric element electrode 31. as electrically resonant at the frequency omega _2, keep finely adjusted pre-inductance L _a.

The power of the frequency component (ω ₁ ) of the first frequency signal generator 41 is applied to the first piezoelectric element electrode 31, and matches the mechanical resonance frequency of the longitudinal vibration of the ultrasonic transducer 30 and mechanically. The ultrasonic vibrator 30 vibrates at a large vibration speed having the frequency ω ₁ . At this time, the power energy of ω _{1 having} a frequency lower than the frequency ω ₂ is not lost by the inductor 33.

The power of the frequency component (ω ₂ ) of the second frequency signal generator 42 matches the electrical resonance frequency due to the capacitance of the inductor 33 and the first piezoelectric element electrode 31, and electrical resonance occurs. a large voltage is applied to the first piezoelectric element electrode 31, the ultrasonic transducer 30 vibrates at a large vibration velocity of the frequency omega _2.

In this way, longitudinal vibration having frequency components of both frequencies ω ₁ and ω ₂ is excited in the ultrasonic transducer 30. Incidentally, it is not always necessary here oscillation frequency omega ₂ components of the vibration of the ultrasonic vibrator 30 of the is a mechanical resonance of the ultrasonic transducer 30.

  By adjusting the amplitude and phase difference between the first frequency signal FS1 generated by the first frequency signal generator 41 and the second frequency signal FS2 generated by the second frequency signal generator 42 at this time, The longitudinal vibration of the sound wave vibrator 30 is a vibration close to a rectangular wave having a vibration speed as shown in FIG.

The third frequency signal generator 43 outputs a third frequency signal FS3 having a frequency ω ₁ that matches the mechanical resonance frequency of the bending vibration of the ultrasonic transducer 30, and at the same time, a fourth frequency signal generator 44. It is amplified to the power oscillation is achieved required for driving the third frequency signal generator 43 outputs a fourth frequency signal FS4 three times the frequency omega ₂ of the ultrasonic transducer 30 by the power amplifier 36 To do. In order to cope with variations in the electrical resonance frequency due to variations in the production of the capacitance C _dB of the second piezoelectric element electrode 32, the inductor 34 has a capacitance C _dB of the second piezoelectric element electrode 32. The inductance L _B is finely adjusted in advance so as to electrically resonate at the frequency ω ₂ .

The power of the frequency component (ω ₁ ) of the third frequency signal generator 43 is applied to the second piezoelectric element electrode 32, and matches the mechanical resonance frequency of the bending vibration of the ultrasonic transducer 30 and mechanically. The ultrasonic vibrator 30 vibrates at a large vibration speed having the frequency ω ₁ . At this time, the power energy of the frequency ω _{1 having} a frequency lower than the frequency ω ₂ is not lost by the inductor 34.

The power of the frequency component (ω ₂ ) of the fourth frequency signal generator 44 matches the electrical resonance frequency due to the capacitance C _dB of the inductor 34 and the second piezoelectric element electrode 32, and the electrical resonance occurs. occur, a large voltage is applied to the piezoelectric element electrodes 32, the ultrasonic vibrator 30 vibrates at a large vibration velocity of the frequency omega _2.

Incidentally, it is not always necessary here oscillation frequency omega ₂ components of the vibration of the ultrasonic vibrator 30 of the is a mechanical resonance of the ultrasonic transducer 30. In this way, bending vibration having frequency components of both frequencies ω ₁ and ω ₂ is excited in the ultrasonic transducer 30.

  By adjusting the amplitude and phase difference of the third frequency signal FS3 generated by the third frequency signal generator 43 and the fourth frequency signal FS4 generated by the fourth frequency signal generator 44 at this time, The bending vibration of the sound wave vibrator 30 is a vibration close to a rectangular wave having a vibration speed as shown in FIG.

  By adjusting the phase difference between the first frequency signal FS1 generated by the first frequency signal generator 41 and the third frequency signal FS3 generated by the third frequency signal generator 43, a Lissajous as shown in FIG. The ultrasonic vibration having the locus of the vibration speed close to the rectangle as compared with the elliptical vibration can be generated.

  As described above, according to the first embodiment, for the longitudinal vibration (longitudinal vibration in the first-order mode) of the ultrasonic transducer 30, vibration having a vibration speed with a frequency ratio of 1: 3 can be generated at the same time, and the phase difference is obtained. By adjusting, the vibration velocity waveform can be approximated to a rectangular wave. As for the bending vibration of the ultrasonic vibrator 30 (second-order bending vibration), vibration having a vibration speed with a frequency ratio of 1: 3 can be generated simultaneously, and the vibration speed waveform can be obtained by adjusting the phase difference. Can be close to a square wave. By bringing the vibration velocity waveform close to a rectangular wave in this way, slippage on the sliding surface (the sliding surface of the sliding member 27 and the vibrators 30a and 30b) is reduced, and as a result, wear on the sliding surface is reduced. Can do.

Incidentally, in addition to the second frequency signal generator 42 and a fourth frequency signal generator 44 for generating a frequency three times higher than omega ₂ of the frequency omega _1, further generates a frequency omega ₁ of 5 times or more the frequency omega A frequency signal generator may be added and connected to the first frequency signal generator 41 and the third frequency signal generator 43 in parallel.

  The first embodiment of the present invention is not limited to the structure of the ultrasonic transducer 30 described above. For example, the ultrasonic transducer described in Japanese Patent Publication No. 1-17353 and Japanese Patent Application Laid-Open No. 2010-22181 The present invention can be applied to ultrasonic vibrators having various structures.

(Embodiment 2)
The inverted microscope according to the second embodiment has a waveform memory 139, instead of the driving unit 53 according to the first embodiment using the first to fourth frequency signal generators 41, 42, 43, 44 as frequency signal generating means. A drive unit 53a using 140 as frequency signal generating means is provided. Further, an ultrasonic transducer 130 is provided instead of the ultrasonic transducer 30. Other structures are the same as those of the first embodiment shown in FIGS. In the description of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 10A is a perspective view showing the shape of the ultrasonic transducer according to the second embodiment. FIG. 10B is a plan view for explaining steps of the ultrasonic transducer according to the second embodiment.

  The ultrasonic vibrator 130 is, for example, a piezoelectric element having a laminated structure, a first piezoelectric element electrode 31 that excites longitudinal vibration (primary mode longitudinal vibration), and bending vibration (secondary mode bending vibration). And a second piezoelectric element electrode 32.

  As shown in FIG. 10A, the ultrasonic transducer 130 has a shape in which a convex portion is formed on a part of a rectangular parallelepiped. That is, as shown in FIG. 10B, the ultrasonic vibrator 130 has two different lengths L1, L2 (L1) as the length in the vibration direction of the longitudinal vibration (the length in the left-right direction of the ultrasonic vibrator 130). Steps are provided on the left and right side surfaces to have> L2).

FIG. 11 is a conceptual diagram illustrating the resonance vibration of the longitudinal first-order mode related to the length L1 and the resonance vibration of the longitudinal third-order mode related to the length L2 in the ultrasonic transducer according to the second embodiment. As shown in FIG. 11, when the longitudinal resonance mode mechanical resonance occurs at the length L1 of the ultrasonic transducer 130 and the longitudinal tertiary mode occurs at the length L2, the longitudinal vibration associated with the length L2. The lengths L1 and L2 are set so that the resonance frequency ω ₃ of the tertiary mode is exactly three times the resonance frequency ω ₄ of the longitudinal primary mode related to the length L1. The resonance frequency of the bending secondary mode is matched with the resonance frequency ω ₃ of the longitudinal primary mode.

  FIG. 12 is a circuit diagram showing the configuration of the drive unit and the ultrasonic transducer according to the second embodiment of the present invention.

  The ultrasonic vibrator 130 is, for example, a piezoelectric element having a laminated structure, a first piezoelectric element electrode 131 that excites longitudinal vibration (primary mode longitudinal vibration), and bending vibration (secondary mode bending vibration). And a second piezoelectric element electrode 132 that excites. The ultrasonic vibrator 130 has a laminated structure similar to that of the ultrasonic vibrator 30 according to the first embodiment although the outer shape is different.

  The drive unit 53a includes inductors 133 and 134 capable of finely adjusting the inductance, power amplifiers 135 and 136, a clock generator 143, counters 141 and 142, a first waveform memory 139, and a second waveform memory 140. , D / A converters 137 and 138.

  An inductor 133 capable of finely adjusting the inductance is connected in series to the first piezoelectric element electrode 131 and connected to the output of the power amplifier 135. The counter 141 counts the clock output from the clock generator 143, and the count value is input as the address of the first waveform memory 139. The first waveform memory 139 outputs digital data having a waveform corresponding to the input address to the D / A converter 137, and synchronizes with the clock output from the clock generator 143 by the D / A converter 137. The D / A converted analog waveform is input to the power amplifier 135. Digital data (waveform data) corresponding to the waveform shown in FIG. 13B described later is recorded in the first waveform memory 139. Every time the counter 141 counts the clock of the clock generator 143, the output data of the waveform memory 139 is recorded. Are updated, and these are repeated, whereby the output of the D / A converter 137 becomes a frequency signal.

  An inductor 134 whose inductance can be finely adjusted is connected in series to the second piezoelectric element electrode 132, and is connected to the output of the power amplifier 136. The counter 142 counts the clock output from the clock generator 143, and the count value is input as the address of the second waveform memory 140. The second waveform memory 140 outputs digital data having a waveform corresponding to the input address to the D / A converter 138, and synchronizes with the clock output from the clock generator 143 by the D / A converter 138. The D / A converted analog waveform is input to the power amplifier 136. Digital data (waveform data) corresponding to the waveform shown in FIG. 14B described later is recorded in the second waveform memory 140, and output data of the waveform memory 140 is counted every time the counter 142 counts the clock of the clock generator 143. Is updated, and these are repeated, whereby the output of the D / A converter 138 becomes a frequency signal.

The first piezoelectric element electrode 131 has an electrostatic capacity (braking capacity) C _d3 derived from the structure. The first piezoelectric element electrode 131 causes electrical resonance with the inductance L _{C of the} inductor 133, and the resonance frequency ω ₅ has the resonance frequency ω ₃ of the longitudinal primary mode related to the length L 1 of the ultrasonic transducer 130. setting the inductance L _C just to be five times. That is, the inductance L _C satisfies the following formula (4).
L _C ≈ 1 / (ω ₅ ² · C _d3 ) = 1 / {(5ω ₃ ) ² · C _d3 } (4)

The second piezoelectric element electrode 132 has an electrostatic capacity (braking capacity) C _d4 derived from the structure. The second piezoelectric element electrodes 132, resulting inductance L _D and electrical resonance of the inductor 134, the resonance frequency omega ₄ is exactly three times the resonant frequency omega ₃ of the secondary flexional mode of the ultrasonic transducer 130 to set the inductance _{L D} so. That is, the inductance _{L D} shall satisfy the following equation (5).
L _D ≈1 / (ω ₄ ² · C _d4 ) = 1 / {(3ω ₃ ) ² · C _d4 } (5)

  Also in the second embodiment, as in the first embodiment, a first electrical resonance circuit is formed between the first piezoelectric element electrode 131 and the inductor 133. The first electrical resonance circuit has a resonance frequency that matches the second frequency that is an odd multiple of 3 or more with respect to the first frequency that matches the mechanical resonance frequency of the longitudinal vibration of the ultrasonic transducer 130. In addition, a second electrical resonance circuit is formed between the second piezoelectric element electrode 132 and the inductor 134. The second electrical resonance circuit has a resonance frequency that matches the second frequency that is an odd multiple of 3 or more with respect to the first frequency that matches the mechanical resonance frequency of the bending vibration of the ultrasonic transducer 130.

FIG. 13A is a graph showing an analog waveform of a signal recorded in the first waveform memory. FIG. 13B is a graph showing a signal obtained by synthesizing a plurality of signals shown in FIG. 13A. The first waveform memory 139 has a fifth frequency signal FS5 as shown in FIG. 13A, a sixth frequency signal FS6 of three times the frequency, and a frequency five times that of the fifth frequency signal FS5. Digital data corresponding to the waveform shown in FIG. 13B obtained by appropriately adjusting and adding the amplitude and phase difference to the seventh frequency signal FS7 is recorded. Fifth frequency signal FS5 is configured so that its frequency is omega ₃ when it is output from the D / A converter 137.

FIG. 14A is a graph showing an analog waveform of a signal recorded in the second waveform memory. FIG. 14B is a graph showing a signal obtained by synthesizing a plurality of signals shown in FIG. 14A. In the second waveform memory 140, an eighth frequency signal FS 8 as shown in FIG. 14A and a ninth frequency signal FS 9 having a frequency three times that of the eighth frequency signal FS 8 are added with the amplitude and phase difference adjusted appropriately. Digital data corresponding to the waveform is recorded. Frequency signal FS8 eighth configured so that its frequency is omega ₃ when it is output from the D / A converter 138.

  Hereinafter, the operation of the ultrasonic transducer 130 according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 15 is a graph showing temporal changes in the vibration speed of the ultrasonic transducer according to the second embodiment of the present invention.

In order to cope with the variation in the electrical resonance frequency due to variations in the production of the capacitance C _d3 of the first piezoelectric element electrode 131, the inductor 133 has the capacitance C _d3 of the first piezoelectric element electrode 131. The inductance is finely adjusted in advance so as to electrically resonate at a frequency five times the frequency ω ₃ .

In order to cope with variations in the electrical resonance frequency due to variations in the production of the capacitance C _d4 of the second piezoelectric element electrode 132, the inductor 134 has a capacitance C _d4 of the second piezoelectric element electrode 132. The inductance is finely adjusted in advance so as to electrically resonate at a frequency three times the frequency ω ₃ .

  The count value of the counter 141 changes in synchronization with the clock of the clock generator 143, and data in the first waveform memory 139 with this count value as an address is output to the D / A converter 137. The analog waveform as shown in FIG. 13B which has been D / A converted is amplified to power necessary for driving the ultrasonic transducer 130 by the power amplifier 135.

The power output from the power amplifier 135 includes the longitudinal primary mode vibration related to the length L1 of the ultrasonic transducer 130 at the frequency ω ₃ of the ultrasonic transducer 130 and the length of the ultrasonic transducer 130 at the frequency ω _4. Since the vibration of the longitudinal tertiary mode related to the length L2 matches the resonance frequency, mechanical resonance occurs and the vibration vibrates with a large vibration amplitude. At this time, the magnitude of the power energy of the frequencies ω ₃ and ω _{4 having} a frequency lower than the frequency ω ₅ is not affected by the inductor 133.

The electric power having the frequency component ω ₅ output from the D / A converter 137 matches the electric resonance frequency of the inductor 133 and the electrostatic capacitance C _d3 of the first piezoelectric element electrode 131, and the electric power resonance occurs, a large voltage is applied to the first piezoelectric element electrode 131, the ultrasonic transducer 130 is vibrated with a large vibration amplitude of the frequency omega _5. Incidentally, it is not always necessary here oscillation frequency omega ₅ component of the vibration of the ultrasonic vibrator 130 at is mechanical resonance of the ultrasonic transducer 130. Thus frequency omega ₄ and omega vibration having a frequency component of ₅ is superimposed ultrasonic transducer 130 to the longitudinal vibration frequency omega ₃ and are longitudinal vibration.

  At this time, if the amplitude and phase difference of the fifth frequency signal FS5, the sixth frequency signal FS6, and the seventh frequency signal FS7 of the waveform data recorded in the first waveform memory 139 are appropriately adjusted. The longitudinal vibration of the ultrasonic transducer 130 is a vibration having a vibration speed as shown in FIG.

  The count value of the counter 142 changes in synchronization with the clock of the clock generator 143, and the data of the second waveform memory 140 having this count value as an address is output to the D / A converter 138. The analog waveform as shown in FIG. 14B that has been D / A converted is amplified by the power amplifier 136 to the power required to drive the ultrasonic transducer 130.

The power output from the power amplifier 136 matches the resonance frequency of the vibration of the bending secondary mode having the frequency ω ₃ of the ultrasonic transducer 130, so that mechanical resonance occurs and the vibration vibrates with a large bending amplitude. At this time, the magnitude of the power energy of the frequency ω _{3 having} a frequency lower than the frequency ω ₄ is not affected by the inductor 134.

The power of the frequency component ω ₄ output from the D / A converter matches the electrical resonance frequency of the inductor 134 and the capacitance C _d4 of the second piezoelectric element electrode 132, and is electrically resonant. occurs, a large voltage is applied to the second piezoelectric element electrode 132, the ultrasonic transducer 130 bends and vibrates in a large vibration amplitude of the frequency omega _4. Incidentally, it is not always necessary here oscillation frequency omega ₄ components of the vibration of the ultrasonic vibrator 130 at is mechanical resonance of the ultrasonic transducer 130. Thus vibration having a frequency component of the frequency omega ₄ to the bending vibration frequency omega ₃ and is superimposed ultrasonic vibrator 130 is vibrated bent.

  At this time, if the amplitude and phase difference of the eighth frequency signal FS8 and the ninth frequency signal FS9 of the waveform data recorded in the second waveform memory 140 are appropriately adjusted, the ultrasonic transducer 130 is used. The bending vibration of FIG. 15 becomes a vibration having a vibration speed as shown in FIG.

  As described above, according to the second embodiment of the present invention, the longitudinal vibration of the ultrasonic transducer 130 can be generated simultaneously in the longitudinal primary mode and the longitudinal tertiary mode with a frequency ratio of 1: 3, and the phase difference is obtained. By adjusting, the vibration velocity waveform can be made closer to a rectangular wave, and furthermore, vibration with a vibration velocity five times that of the longitudinal primary mode can be added, so that it can be made closer to a rectangular wave. As for the bending secondary mode vibration of the ultrasonic vibrator 130, vibration having a frequency ratio of 1: 3 can be generated at the same time, and the vibration velocity waveform can be made close to a rectangular wave by adjusting the phase. By bringing the vibration velocity waveform close to a rectangular wave in this way, slippage on the sliding surface (the sliding surface of the sliding member 27 and the vibrators 30a and 30b) is reduced, and as a result, wear on the sliding surface is reduced. Can do.

(Embodiment 3)
The inverted microscope according to the third embodiment replaces the drive unit 53 according to the first embodiment using the first to fourth frequency signal generators 41, 42, 43, and 44 as frequency signal generating means, and uses PWM (pulse width). (Modulation) The signal generator 241 and the MOS-FETs 237, 238, 239, and 240 are provided as a drive unit 53b using frequency signal generating means. Trimmer capacitors 235 and 236 are also provided. In the description of the third embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 16 is a circuit diagram showing the configuration of the drive unit and the ultrasonic transducer according to the third embodiment of the present invention.

  The ultrasonic transducer 230 is, for example, a piezoelectric element having a laminated structure, and a first piezoelectric element electrode 231 that excites longitudinal vibration (primary mode longitudinal vibration) and bending vibration (secondary mode bending vibration). And a second piezoelectric element electrode 232 that excites. The ultrasonic transducer 230 has the same structure as the ultrasonic transducer 30 according to the first embodiment.

  The drive unit 53b according to the third embodiment of the present invention includes inductors 233 and 234, trimmer capacitors 235 and 236 whose capacitance can be adjusted, MOS-FETs 237, 238, 239, and 240, a PWM signal generator 241, and the like. .

The input of the first piezoelectric element electrode 231 is connected in parallel to a trimmer capacitor 235 whose capacitance can be adjusted, and is connected in series to the output of the inductor 233. The input of the inductor 233 is connected to the drains of the MOS-FETs 237 and 238. MOS-FET 237 has a source connected to a DC voltage source _{E o,} MOS-FET238 source is connected to ground. The gates of the MOS-FETs 237 and 238 are connected to the PWM signal generator 241 and receive a signal from the PWM signal generator 241 to perform a switching operation.

The input of the second piezoelectric element electrode 232 is connected in parallel to a trimmer capacitor 236 whose capacitance can be adjusted, and is connected in series to the output of the inductor 234. The input of the inductor 234 is connected to the drains of the MOS-FETs 239 and 240. MOS-FET239 has a source connected to a DC voltage source _{E o,} MOS-FET240 source is connected to ground. The gates of the MOS-FETs 239 and 240 are connected to the PWM signal generator 241 and receive a signal from the PWM signal generator 241 to perform a switching operation.

The first piezoelectric element electrode 231 has a capacitance (braking capacity) _Cd5 derived from the structure. The first piezoelectric element electrodes 231, cause electrical resonance between the inductance L _E of the trimmer capacitor 235 and the inductor 233, the resonance frequency omega ₇ the resonance frequency omega ₆ of the longitudinal primary mode of the ultrasonic transducer 230 to set the inductance L _E just to be three-fold. That is, when the capacitance of the trimmer capacitor 235 and C _T5, the inductance L _E is set as in equation (6) below is established.
_{L E ≒ 1 / {ω 7} 2 · (C d5 + C T5)} = 1 / {(3ω 6) 2 · (C d5 + C T5)} ... (6)

The second piezoelectric element electrode 232 has a capacitance (braking capacity) Cd6 derived from the structure. The second piezoelectric element electrodes 232, cause electrical resonance between the inductance L _F of the trimmer capacitor 236 and the inductor 234, the resonance frequency omega ₇ the resonance frequency omega ₆ of the bending second-order mode of the ultrasonic transducer 230 setting the inductance L _F just to be tripled. That is, when the capacitance of the trimmer capacitor 236 and C _T6, the inductance L _F is set such that the following formula is valid (7).
L _F ≈ 1 / {ω ₇ ² · (C _d6 + C _T6 )} = 1 / {(3ω ₆ ) ² · (C _d6 + C _T6 )} (7)

  In the third embodiment, a first electrical resonance circuit is formed between the first piezoelectric element electrode 231, the trimmer capacitor 235 and the inductor 233. The first electrical resonance circuit has a resonance frequency that matches the second frequency that is an odd multiple of 3 or more with respect to the first frequency that matches the mechanical resonance frequency of the longitudinal vibration of the ultrasonic transducer 130. A second electrical resonance circuit is formed between the second piezoelectric element electrode 232, the trimmer capacitor 236, and the inductor 234. The second electrical resonance circuit has a resonance frequency that matches the second frequency that is an odd multiple of 3 or more with respect to the first frequency that matches the mechanical resonance frequency of the bending vibration of the ultrasonic transducer 130.

  17A to 17C are graphs for explaining the first pulse waveform generated by the PWM signal generator. When the tenth frequency signal FS10 shown in FIG. 17A and the eleventh frequency signal FS11 having a frequency three times that of the tenth frequency signal FS10 are added, an analog waveform as shown in FIG. 17B is obtained. When the analog waveform shown in FIG. 17B is PWM (pulse width modulation), a first pulse waveform as shown in FIG. 17C is obtained. The first pulse waveform shown in FIG. 17C is applied to the gates of the MOS-FETs 237 and 238. Note that the MOS-FETs 237 and 238 are set so as not to be turned on simultaneously.

  18A to 18C are graphs for explaining a second pulse waveform generated by the PWM signal generator. When the twelfth frequency signal FS12 shown in FIG. 18A and the thirteenth frequency signal FS13 having a frequency three times that of the twelfth frequency signal FS12 are added, an analog waveform as shown in FIG. 18B is obtained. When the analog waveform shown in FIG. 18B is PWM (pulse width modulation), a second pulse waveform as shown in FIG. 18C is obtained. The second pulse waveform shown in FIG. 18C is applied to the gates of the MOS-FETs 239 and 240. The MOS-FETs 239 and 240 are set so as not to be turned on at the same time.

  Hereinafter, the operation of the ultrasonic transducer 230 according to the third embodiment of the present invention will be described with reference to FIGS.

In order to deal with the fact that the electrical resonance frequency varies due to variations due to manufacturing reasons of the capacitance C _d5 of the first piezoelectric element electrode 231, the capacitance C of the inductor 233 and the first piezoelectric element electrode 231. and _d5, so that the capacitance _{C T5} of the trimmer capacitor 235 is electrically resonant at the frequency omega _7, keep fine-tune the capacitance _{C T5} in advance the trimmer capacitor 235.

  With the first pulse waveform shown in FIG. 17C output from the PWM signal generator 241, the MOS-FETs 237 and 238 are switched and amplified to the power necessary to drive the ultrasonic transducer 230.

Since the power output from the drains of the MOS-FETs 237 and 238 matches the mechanical resonance frequency of the longitudinal first mode vibration of the frequency ω ₆ of the ultrasonic transducer 230, mechanical resonance occurs and a large bending occurs. Vibrates with amplitude. At this time, the magnitude of the power energy of the frequency ω _{6 having} a frequency lower than the frequency ω ₇ is not affected by the inductor 233.

The power of the frequency component ω ₇ output from the drains of the MOS-FETs 237 and 238 is the inductor 233, the capacitance C _{d5 of} the first piezoelectric element electrode 231 and the capacitance C _T5 of the trimmer capacitor 235. occurs electric resonance consistent with electrical resonant frequency by a large voltage is applied to the first piezoelectric element electrode 231, the ultrasonic transducer 230 is vibrated with a large vibration amplitude of the frequency omega _7. Incidentally, it is not always necessary here oscillation frequency omega ₇ component of the vibration of the ultrasonic vibrator 230 in a mechanical resonance of the ultrasonic transducer 230. In this way, the vibration having the frequency component of ω ₇ is superimposed on the longitudinal vibration of the frequency ω ₆ , and the ultrasonic transducer 230 vibrates longitudinally.

The power whose frequency component output from the drains of the MOS-FETs 237 and 238 is higher than the frequency ω ₇ is composed of the inductor 233, the capacitance of the first piezoelectric element electrode 231, and the capacitance of the trimmer capacitor 235. Therefore, it does not contribute to the vibration of the ultrasonic transducer 230.

In order to deal with the fact that the electrical resonance frequency varies due to variations due to manufacturing reasons of the capacitance C _d6 of the second piezoelectric element electrode 232, the capacitance C of the inductor 234 and the second piezoelectric element electrode 232 and _d6, so that the capacitance _{C T6} of the trimmer capacitor 236 is electrically resonant at the frequency omega _7, keep fine-tune the capacitance _{C T6} in advance the trimmer capacitor 236.

  With the second pulse waveform shown in FIG. 18C output from the PWM signal generator 241, the MOS-FETs 239 and 240 are switched and amplified to power necessary for driving the ultrasonic transducer 230.

The power output from the drains of the MOS-FETs 239 and 240 matches the mechanical resonance frequency of the bending secondary mode vibration at the frequency ω ₆ of the ultrasonic transducer 230, so that mechanical resonance occurs and large bending occurs. Vibrates with amplitude. At this time, the magnitude of the power energy of the frequency ω _{6 having} a frequency lower than the frequency ω ₇ is not affected by the inductor 234.

The power of the frequency component ω ₇ output from the drains of the MOS-FETs 239 and 240 is the inductor 234, the capacitance C _{d6 of} the second piezoelectric element electrode 232, and the capacitance C _T6 of the trimmer capacitor 236. In accordance with the electrical resonance frequency of, electrical resonance occurs, a large voltage is applied to the second piezoelectric element electrode 232, and the ultrasonic transducer 230 vibrates with a large vibration amplitude of the frequency ω7. Incidentally, it is not always necessary here oscillation frequency omega ₇ component of the vibration of the ultrasonic vibrator 230 in a mechanical resonance of the ultrasonic transducer 230. In this way, the vibration having the frequency component of ω ₇ is superimposed on the bending vibration of frequency ω ₆ , and the ultrasonic transducer 230 bends and vibrates.

The power whose frequency component output from the drains of the MOS-FETs 239 and 240 is higher than the frequency ω ₇ is obtained by a low-pass filter constituted by the inductor 234, the capacitance of the second piezoelectric element electrode 232, and the trimmer capacitor 236. Since it is blocked, it does not contribute to the vibration of the ultrasonic transducer 230.

  According to the third embodiment of the present invention, vibrations having a vibration speed with a frequency ratio of 1: 3 can be generated at the same time with respect to the longitudinal vibrations (primary mode longitudinal vibrations) of the ultrasonic transducer 230, and the phase difference is obtained. By adjusting, the vibration velocity waveform can be approximated to a rectangular wave. As for the bending vibration (second-order bending vibration) of the ultrasonic vibrator 230, vibration having a vibration speed with a frequency ratio of 1: 3 can be generated at the same time, and by adjusting the phase difference, a vibration speed waveform can be obtained. Can be close to a square wave. By bringing the vibration velocity waveform close to a rectangular wave in this way, slippage on the sliding surface (the sliding surface of the sliding member 27 and the vibrators 30a and 30b) is reduced, and as a result, wear on the sliding surface is reduced. Can do.

(Modification of Embodiment 3)
FIG. 19 is a circuit diagram showing a configuration of a drive unit and an ultrasonic transducer according to a modification of the third embodiment of the present invention.

  In the modification of the third embodiment, the trimmer capacitors 235 and 236 for adjusting the electrical resonance frequency are connected in series to the first piezoelectric element electrode 231 and the second piezoelectric element electrode 232, respectively. Unlike the third embodiment, the other configurations are the same.

The trimmer capacitor 235 and 236, each of the first piezoelectric element electrodes 231, when connected in series to the second piezoelectric element electrodes 232, formula showing the inductance _{L E} of the inductor 233 shown in the third embodiment (6), The following equation (8) is obtained.
L _E ≈ 1 / [ω ₇ ² · {C _d5 · C _T5 / (C _d5 + C _T5 )}]
= 1 / [(3ω ₆ ) ² · {C _d5 · C _T5 / (C _d5 + C _T5 )}] (8)

Similarly, equation showing the inductance _{L F} of the inductor 234 (7), the following equation (9).
L _F ≈ 1 / [ω ₇ ² · {C _d6 · C _T6 / (C _d6 + C _T6 )}]
= 1 / [(3ω ₆ ) ² · {C _d6 · C _T6 / (C _d6 + C _T6 )}] (9)

In the above formulas (8) and (9), if C _d <C _T , the same effect as in the third embodiment can be obtained in this modified example.

  In the first to third embodiments and the modifications described above, a first electrical resonance circuit is formed for the first piezoelectric element electrode that excites longitudinal vibration (longitudinal vibration of the primary mode). The second electrical resonance circuit is formed with respect to the second piezoelectric element electrode that excites bending vibration (second-order mode bending vibration). You may make it form an electrical resonance circuit only in any one of a 1st piezoelectric element electrode and a 2nd piezoelectric element electrode.

DESCRIPTION OF SYMBOLS 1 Inverted microscope 2 Electric stage 3 Main body part 4 Transmission illumination part 5 Control apparatus 6 Objective lens 7 Reflection mirror 8 Imaging optical system 9 Eyepiece 10 Lens tube 11 Transmission illumination support | pillar 12 Arm 13 Light source 14 Lamp house 15 Condenser lens 16 Condenser unit 17 Collector lens 18 Field stop 19 Reflecting mirror 21 Base 23 Guide rail 22 Moving part (stage)
27 Sliding member (sliding part)
24 Ultrasonic Actuator 28 Scale 25 Encoder 26 Opening 29 Holding Mechanism 30, 130, 230 Ultrasonic Vibrator 30a, 30b Vibrator 31, 32, 131, 132, 231, 232 Piezoelectric Element Electrode 33, 34, 133, 134, 233 , 234 Inductor 35, 36, 135, 136 Power amplifier 37, 38, 39, 40 Resistor 41, 42, 43, 44 Frequency signal generator 51 Control unit 53, 53a, 53b Drive unit 52 Instruction unit 54 Detection unit 61, 62, 65, 68 Plate-shaped piezoelectric body 63, 66 Driving bending vibration electrode 64 Longitudinal vibration detecting electrode 67 Driving longitudinal vibration electrode 69 GND electrode 70, 71, 72, 73, 74 Lead pattern 75, 76, 77, 78 79, 80, 81, 82 Electrode pattern 137, 138 D / A converter 139, 1 0 waveform memory 141 the counter 143 clock generator 235, 236 trimmer capacitor 237,238,239,240 MOS-FET
241 PWM signal generator

Claims (9)

An ultrasonic transducer having first and second piezoelectric element electrodes, each of which excites one of longitudinal vibration and bending vibration included in the ultrasonic elliptical vibration;
A first frequency signal is generated that includes a first frequency that matches the mechanical resonance frequency of the ultrasonic transducer and a second frequency that has an odd multiple of 3 or more with respect to the first frequency. 1 frequency signal generator,
A second frequency signal generator that generates a second frequency signal including a third frequency that matches a mechanical resonance frequency of the ultrasonic transducer;
A first inductance which is connected to the first piezoelectric element electrode and forms a first electrical resonance circuit having a resonance frequency matching the second frequency with the first piezoelectric element electrode; A first electrical resonance circuit forming unit having:
An ultrasonic motor comprising: The second frequency signal generated by the second frequency signal generator further includes a fourth frequency having an odd multiple of 3 or more with respect to the third frequency,
A second inductance which is connected to the second piezoelectric element electrode and forms a second electrical resonance circuit having a resonance frequency matching the fourth frequency with the second piezoelectric element electrode; The ultrasonic motor according to claim 1, further comprising: a second electrical resonance circuit forming unit having the same.   The ultrasonic elliptical vibration matches the mechanical resonance frequency of the longitudinal vibration of the ultrasonic vibrator with the mechanical resonance frequency of the bending vibration, and is excited at a frequency that matches the resonance frequency. The ultrasonic motor according to claim 1, wherein the ultrasonic motor is formed by giving a phase difference to the bending vibration.   The said 1st electrical resonance circuit formation part is provided with the inductor which has the said 1st inductance connected in series with the said 1st piezoelectric element electrode, The any one of Claims 1-3 characterized by the above-mentioned. The ultrasonic motor according to item.   The first electrical resonance circuit forming unit is connected in series or in series to the first piezoelectric element electrode and an inductor having the first inductance connected in series to the first piezoelectric element electrode. The ultrasonic motor according to claim 1, further comprising a capacitor.   The said 2nd electrical resonance circuit formation part is provided with the inductor which has the said 2nd inductance connected in series with the said 2nd piezoelectric element electrode, The any one of Claims 2-5 characterized by the above-mentioned. The ultrasonic motor according to item.   The second electrical resonance circuit forming unit is connected in series or in series to the second piezoelectric element electrode and an inductor having the second inductance connected in series to the second piezoelectric element electrode. The ultrasonic motor according to claim 2, further comprising a capacitor.   The ultrasonic motor according to claim 1, wherein a phase difference and an amplitude ratio of the frequency component of the second frequency can be adjusted with respect to the frequency component of the first frequency.   The ultrasonic motor according to claim 1, wherein a phase difference and an amplitude ratio of the frequency component of the fourth frequency can be adjusted with respect to the frequency component of the third frequency.

Images