Abstract:
An ultrasonic motor comprises first piezoelectric oscillators alternately arranged with first polarized regions having a first direction of polarization and second polarized regions having a second direction of polarization opposite to the first direction of polarization. The first piezoelectric oscillators undergo bending vibration in a first direction upon input of drive signals having a same phase to the first polarized regions and the second polarized regions to thereby excite the first and second polarized regions. Second piezoelectric oscillators are laminated to the first piezoelectric oscillators in a second direction generally perpendicular to the first direction for undergoing elongation and contraction vibration in the first direction. When a driving signal is applied to the first and second piezoelectric oscillators a drive force is generated by a combination of the bending vibration of the first piezoelectric oscillators and the elongation and contraction vibration of the second piezoelectric oscillators.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to ultrasonic motors used in a timepiece, a camera, a printer, a storage apparatus and so on, and more particularly to an ultrasonic motor with a magnified drive force. 
     2. Description of the Related Art 
     In recent times, in the field of micromechanics attention is attracted to a ultrasonic motor utilizing as power, an elliptical motion as synthesized vibration of elongation and contraction vibration and bending vibration produced in a piezoelectric element applied with a drive signal of alternating current voltage or the like. 
     Here, an explanation will be given of an ultrasonic motor  4  and an ultrasonic motor  5  as conventional ultrasonic motors in reference to FIGS. 13 a  and  13   b.    
     As shown by FIG. 13 a,  the ultrasonic motor  4  is provided with the structure installed with a projection  41  for taking out an output for moving a moving body (illustration is omitted) by being brought into press contact with the moving body at one end face of a piezoelectric element  40  in a shape of a rectangular parallelepiped. 
     In this case, the piezoelectric element  40  is provided with four of a polarized region  40   a,  a polarized region  40   b,  a polarized region  40   c  and a polarized region  40   d  which are polarized in the same polarities in the thickness direction and arranged in two rows each comprising two pieces thereof. Further, the polarized regions  40   a,    40   b,    40   c  and  40   d  are respectively provided with electrodes. Further, the electrode on the polarized region  40   a  and the electrode on the polarized region  40   d  which are diagonally opposedly positioned, are shortcircuited by using a lead wire. Similarly, the electrode on the polarized region  40   b  and the electrode on the polarized region  40   c  are shortcircuited by using a lead wire. 
     The ultrasonic motor  4  moves the moving body in a positive direction by inputting drive signals to the polarized regions  40   a  and  40   d  and moves the moving body in a reverse direction by inputting drive signals to the polarized regions  40   b  and  40   c.    
     The ultrasonic motor  5  is provided with a piezoelectric element  50  shown by FIG. 13 b  as a power source. The piezoelectric element  50  is provided with four of a polarized region  50   a,  a polarized region  50   b,  a polarized region  50   c  and a polarized region  50   d  which are polarized in the same polarities in the thickness direction and arranged in two rows each constituting two pieces thereof similar to the piezoelectric element  40 . The polarized regions  50   a,    50   b,    50   c  and  50   d  are respectively provided with electrodes insulated from each other. 
     The ultrasonic motor  5  moves a moving body, not illustrated, in the positive direction by inputting drive signals X having the same phase to the polarized regions  50   a  and  50   d  and inputting drive signals having a phase advanced from that of the drive signal X by 90 degree to the polarized regions  50   b  and  50   c.  Further, the ultrasonic motor  5  moves the moving body, not illustrated, in the reverse direction by inputting drive signals having a phase retarded from that of the drive signal X by 90 degree to the polarized regions  50   b  and  50   c.    
     However, the ultrasonic motor  4  utilizes only a half of the polarized regions of the piezoelectric element  40  as the power source and therefore, large output is not provided. 
     Further, although the ultrasonic motor  5  utilizes all of the polarized regions of the piezoelectric element  50  as a power source, there is needed a circuit for shifting the phase of the input signal by 90 degree. Particularly, when there is carried out self-excited oscillation for driving the ultrasonic motor by utilizing the self-excited oscillation, two input signals having different phases are used and therefore, the constitution of a self-excited oscillation drive circuit becomes complicated and is difficult to realize. 
     Further, the ultrasonic motor  4  utilizes the piezoelectric element  40  and the ultrasonic motor  5  utilizes the piezoelectric element  50  as both a source of elongation and contraction vibration and a source of bending vibration and accordingly, large elongation and contraction vibration or bending vibration cannot be provided. That is, sufficient output cannot be provided by the conventional ultrasonic motors  4  and  5 . Therefore, in order to provide large output by using the ultrasonic motor  4  or  5 , as shown by FIG. 14, for example, a plurality of the ultrasonic motors  4  must be arranged in parallel by using an exclusive jig, which hampers downsizing thereof. Also in this case, vibration escapes from the exclusive jig and, therefore, the output of the ultrasonic motor is reduced. 
     Further, the elongation and contraction vibration and the bending vibration cannot be controlled independently from each other and accordingly, a moving speed and a drive force of the moving body cannot be controlled widely. 
     SUMMARY OF THE INVENTION 
     Hence, it is an object of the present invention to provide an ultrasonic motor in which all of polarized regions of piezoelectric elements are simultaneously utilized and are driven by only input signals having the same phase or an inverted phase and both of large elongation and contraction vibration and bending vibration can separately be controlled and which is provided with large output at low voltage and can be downsized. 
     In order to resolve the above-described problem, according to an aspect of the invention, there is provided an ultrasonic motor comprising first piezoelectric oscillators totally having a plurality of polarized regions alternately arranged with first polarized regions polarized in same polarities and second polarized regions polarized reversely to the first polarized regions and producing a bending vibration by inputting drive signals having a same phase to the first polarized regions and the second polarized regions to thereby excite the first polarized regions. Second the polarized regions and second piezoelectric oscillators laminated integrally to the first piezoelectric oscillators and produce an elongation and contraction vibration by exciting polarized regions polarized in same polarities. A drive force is provided by an elliptic vibration synthesized with the bending vibration produced in the first piezoelectric oscillators and the elongation and contraction vibration produced in the second piezoelectric oscillators. 
     In this case, for example, barium titanate, lead titanate, lithium niobate, lithium tantalate or the like is used for the piezoelectric oscillator. Further, as the signal having the same phase, for example, a sine wave is used. 
     According to the invention, the first piezoelectric oscillators are totally and alternately provided with the first polarized regions polarized in the same polarities and the second polarized regions polarized reverse to the first polarized regions and the drive signals having the same phase are inputted to the plurality of polarized regions and accordingly, large bending vibration is produced. Further, the second piezoelectric oscillators constituting the elongation and contraction vibration source which are installed separately from the first piezoelectric oscillators, produce large elongation and contraction vibration. Further, the first piezoelectric oscillators and the second piezoelectric oscillators are integrally formed and accordingly, the bending vibration and the elongation and contraction vibration are synthesized without leakage. Accordingly, the ultrasonic motor having large output can be fabricated. 
     Therefore, in the case of providing an output the same as that of the conventional motor, the ultrasonic motor can be downsized. 
     Further, by separately controlling the first piezoelectric oscillators and the second piezoelectric oscillators, the elongation and contraction vibration and the bending vibration can separately be controlled. 
     Further, according to another aspect of the invention, there is provided the ultrasonic motor wherein the plurality of polarized regions of the first piezoelectric oscillator are arranged in two rows along one direction. 
     According to the invention, other than achieving operation similar to that in the above-described aspect of the invention, the ultrasonic motor for taking out output from a face in parallel with a laminating direction can be fabricated. 
     Further, according to another aspect of the invention, there is provided the ultrasonic motor wherein the plurality of polarized regions of the first piezoelectric oscillator are arranged in one row along one direction. 
     According to the invention, other than achieving operation similar to those in the above-described aspects of the invention, the ultrasonic motor for taking out output from a face orthogonal to the laminating direction can be fabricated and accordingly, an apparatus mounted with the ultrasonic motor can be thinned. 
     Further, according to another aspect of the invention, there is provided the ultrasonic motor wherein respective pluralities of the first piezoelectric oscillators and the second piezoelectric oscillators are integrally laminated. 
     In this case, for example, the first piezoelectric oscillators and the second piezoelectric oscillators are alternately laminated. Further, numbers thereof are, for example, four sheets, respectively. 
     According to the invention, other than achieving operation similar to those in the above-described aspects of the invention, respective pluralities of the first piezoelectric oscillators and the second piezoelectric oscillators are used and accordingly, the output is further magnified. Further, by changing a ratio of numbers of sheets of the first piezoelectric oscillators and the second piezoelectric oscillators, a ratio of magnitudes of the elongation and contraction vibration and the bending vibration can be changed. 
     Further, according to another aspect of the invention, there is provided the ultrasonic motor wherein the plurality of polarized regions of the first piezoelectric oscillators and the polarized regions of the second piezoelectric oscillators are inputted with drive signals having a same phase from a same signal source. 
     In this case, an alternating current power source is used as the signal source. 
     According to the invention, the ultrasonic motor is driven by a single one of an input signal and accordingly, a self-excited oscillation circuit is simplified, therefore, self-excited oscillation drive is easily realized. 
     Further, the same signal source is used as a signal source of the same phase and accordingly, a peripheral circuit of the ultrasonic motor is simplified. 
     Further, according to another aspect of the invention, there is provided the ultrasonic motor wherein either of the first piezoelectric oscillators and the second piezoelectric oscillators is connected to a signal source via switching means for inverting the phase of the drive signals. 
     In this case, for example, switches are used as the switching means. 
     According to the invention, either of the first piezoelectric oscillators and the second piezoelectric oscillators is connected to the signal source via the switching means for inverting a phase of a signal. 
     Therefore, by simply switching the switching means, an input signal to either of the first piezoelectric oscillators and the second piezoelectric oscillators is provided with an inverted phase. That is, the drive direction of the ultrasonic motor is reversed. 
     Further, according to another aspect of the invention, there is provided an electronic apparatus having a ultrasonic motor, the electronic apparatus comprising the ultrasonic motor, described above. 
     In this case, as the electronic apparatus, there is pointed out, for example, an electronic timepiece, a measuring instrument, a camera, a printer, a printing machine, a machine tool, a robot, a moving apparatus, a storage apparatus or the like. 
     According to the invention, there is used the ultrasonic motor, described above, having an output larger than that of the conventional ultrasonic motor and therefore, the size of the ultrasonic motor and its peripheral circuit can be downsized whereby the electronic apparatus having the ultrasonic motor can be downsized. 
     Further, as a drive method of the ultrasonic motor, particularly, self-excited oscillation drive is easily applicable and therefore, the peripheral circuit can further be downsized. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1 a  and  1   b  and  1   c  are views showing a constitution of anultrasonic motor  1  according to a first embodiment of the invention; 
     FIG. 2 is a view showing a constitution of a piezoelectric element  10  used in the ultrasonic motor  1 ; 
     FIGS. 3 a,    3   b,    3   c,    3   d,    3   e  and  3   f  are views showing structures of a piezoelectric oscillator  11 , a piezoelectric oscillator  12  and electrodes  16   a,    16   b,    16   c,    16   d,    16   e,    16   f  and  16   g  used in the piezoelectric element  10 ; 
     FIGS. 4 a ,  4   b,    4   c  and  4   d  are views showing operation of the ultrasonic motor  1 ; 
     FIGS. 5 a ,  5   b,    5   c  and  5   d  are views showing the operation of the ultrasonic motor  1 ; 
     FIG. 6 is a view showing a constitution of an ultrasonic motor  2  according to a second embodiment of the invention; 
     FIGS. 7 a,    7   b,    7   c,    7   d,    7   e  and  7   f  are views showing structures of a piezoelectric oscillator  21 , a piezoelectric oscillator  22  and electrodes  26   a,    26   b,    26   c,    26   d,    26   e,    26   f  and  26   g  used in a piezoelectric element  20  of the ultrasonic motor  2 ; 
     FIGS. 8 a ,  8   b,    8   c  and  8   d  are views showing operation of the ultrasonic motor  2 ; 
     FIGS. 9 a,    9   b,    9   c  and  9   d  are views showing the operation of the ultrasonic motor  2 ; 
     FIGS. 10 a ,  10   b,    10   c,    10   d,    10   e  and  10   f  are views showing structures of a piezoelectric oscillator  31 , a piezoelectric oscillator  32  and electrodes  36   a,    36   b,    36   c,    36   d,    36   e  and  36   f  used in a piezoelectric element  30 ; 
     FIG. 11 is a diagram showing operation of a ultrasonic motor  3  according to a third embodiment of the invention; 
     FIG. 12 is a block diagram showing a constitution of an electronic apparatus  6  having a ultrasonic motor according to a forth embodiment of the invention; 
     FIGS. 13 a  and  13   b  are views showing constitutions of an ultrasonic motor  4  and a ultrasonic motor  5  as conventional examples; and 
     FIG. 14 is a view showing a method of using a plurality of the ultrasonic motors  4  or the ultrasonic motors  5  in parallel with each other as a conventional example. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A detailed explanation will be given of embodiments to which the invention is applied in reference to FIGS. 1 a  through FIG. 12 as follows. 
     FIG. 1 a  through FIG. 5 d  are views for explaining an ultrasonic motor  1  according to a first embodiment, FIG.  6  through FIG. 9 d  are views for explaining a ultrasonic motor  2  according to a second embodiment and FIG. 10 a  through FIG. 11 are views showing a third embodiment. 
     FIG. 12 is a diagram for explaining an electronic apparatus utilizing an ultrasonic motor according to a fourth embodiment. 
     First Embodiment 
     FIGS. 1 a  and  1   b  are views showing a total of a constitution of an ultrasonic motor  1 . 
     As shown by a top view of FIG. 1 a  and a front view of FIG. 1 b,  the ultrasonic motor  1  is constituted by a piezoelectric element  10 , a supporting member  13  for supporting the piezoelectric element  10  and an object portion  14  having a moving body  14   a  which is brought into contact with an end face of the piezoelectric element  10  and is moved by the piezoelectric element  10 . That is, the ultrasonic motor  1  is a ultrasonic motor for moving the moving body  14   a  in a direction in parallel with the end face of the piezoelectric element  10 . 
     As shown by FIG. 2, the piezoelectric element  10  is constituted by a structure in which, for example, four sheets of piezoelectric oscillators  11  (first piezoelectric oscillators) are integrally laminated as a source of bending vibration, on top thereof, for example, four sheets of piezoelectric oscillators  12  (second piezoelectric oscillators) are integrally laminated as a source of elongation and contraction vibration via a piezoelectric oscillator  18  constituting an insulating member. Further, the piezoelectric element  10  is provided with electrodes (illustration is omitted in FIG.  2 ), mentioned later. 
     Further, there may be installed a projection for driving the moving body  14   a  by being brought into contact therewith at substantially a central portion of the end face. 
     Here, an explanation will be given of polarized states of the piezoelectric oscillator  11  and the piezoelectric oscillator  12  as well as the structure of electrodes of the piezoelectric element  10  in reference to FIGS. 3 a,    3   b,    3   c,    3   d,    3   e  and  3   f.    
     FIG. 3 a  is a view showing a side face  10   a  (refer to FIG. 2) of the piezoelectric element  10  and FIG. 3 f  is a view showing a side face  10   b  (refer to FIG. 2) thereof. FIG. 3 b  is a top view of odd number ones of the piezoelectric oscillators  11  and a bottom view of even number ones thereof and FIG. 3 c  is a bottom view of odd number ones of the piezoelectric oscillators  11  and a top view of even number ones thereof. Further, FIG. 3 d  is a top view of odd number ones of the piezoelectric oscillators  12  and a bottom view of even number ones thereof and FIG. 3 e  is a bottom view of odd number ones of the piezoelectric oscillators  12  and a top view of even number ones thereof. That is, coupling faces of the respective piezoelectric oscillators constitute common electrodes. 
     First, an explanation will be given of polarized states of the piezoelectric oscillator  11  and the piezoelectric oscillator  12 . 
     As shown by FIG. 3 b  and FIG. 3 c,  the piezoelectric oscillator  11  is constituted by a structure in which four of a polarized region  11   a,  a polarized region  11   b,  a polarized region  11   c  and a polarized region  11   d  formed by dividing the piezoelectric oscillator  11  in two in the vertical direction and dividing the piezoelectric oscillator  11  in two also in the horizontal direction, are polarized reversely alternately in a laminating direction. That is, the polarized region  11   a  and the polarized region  11   d  are brought into a state, for example, top faces thereof become plus and the polarized region  11   b  and the polarized region  11   c  are brought into a state in which, for example, top faces thereof become minus. 
     Further, as shown by FIG. 3 d  and FIG. 3 e,  substantially an entire face of the piezoelectric oscillator  12  constitutes a single one of a polarized region and the piezoelectric oscillator  12  is polarized such that, for example, a top face thereof becomes plus in the laminating direction. 
     Next, an explanation will be given of the structure of the electrodes of the piezoelectric element  10  in reference to FIGS. 3 a,    3   b,    3   c,    3   d  and  3   e  and  3   f.    
     The piezoelectric element  10  is provided with an electrode  16   a,  an electrode  16   b,  an electrode  16   c,  an electrode  16   d,  an electrode  16   e,  an electrode  16   f  and an electrode  16   g.    
     Among them, the electrodes  16   a,    16   b,    16   c,    16   d  and  16   e  are electrodes for inputting signals to the piezoelectric oscillator  11  and the electrodes  16   f  and  16   g  are electrodes for inputting signals to the piezoelectric oscillator  12 . 
     The electrode  16   a  substantially covers one face of the polarized region  11   a  of the piezoelectric oscillator  11  and a portion thereof is drawn to the side face  10   a.  That is, all of top faces of the polarized regions  11   a  of four sheets of the piezoelectric oscillators  11  are brought into the same potential by the electrode  16   a  continuous thereto via portions thereof drawn to the side face  10   a.    
     Similarly, the electrode  16   b  substantially covers one face of the polarized region  11   b  of the piezoelectric oscillator  11  and a portion thereof is drawn to the side face  10   a.  That is, all of top faces of the polarized regions  11   b  of four sheets of the piezoelectric oscillators  11  are brought into the same potential by the electrode  16   b  continuous thereto via portions thereof drawn to the side face  10   a.    
     Further, the electrode  16   c  substantially covers one face of the polarized region  11   c  of the piezoelectric oscillator  11  and a portion thereof is drawn to the side face  10   b.  That is, all of faces on one side of the polarized regions  11   c  of four sheets of the piezoelectric oscillators  11  are brought into the same potential by the electrode  16   c  continuous thereto via portions thereof drawn to the side face  10   b.    
     Similarly, the electrode  16   d  substantially covers one face of the polarized region  11   d  of the piezoelectric oscillator  11  and a portion thereof is drawn to the side face  10   b.  That is, all of faces on one side of the polarized regions  11   d  of four sheets of the piezoelectric oscillators  11  are brought into the same potential by the electrode  16   d  continuous thereto via portions thereof drawn to the side face  10   b.    
     Further, the electrode  16   e  covers all of other faces of four of the polarized regions  11   a,    11   b,    11   c  and  11   d  of the piezoelectric oscillator  11  and portions thereof are drawn to the side face  10   a.  That is, all of the other faces of the four polarized regions of four sheets of the piezoelectric oscillators  11  are brought in the same potential by the electrode  16   d  continuous thereto via portions thereof drawn to the side face  10   a.    
     Further, in the case in which in the piezoelectric oscillator  11 , with the electrode  16   e  as a reference electrode, the same drive signal is inputted to the electrodes  16   a,    16   b,    16   c  and  16   d,  when the polarized regions  11   a  and  11   d  are elongated, the polarized regions  11   b  and  11   c  are contracted, further, when the polarized regions  11   a  and  11   d  are conversely contracted, the polarized regions  11   b  and  11   c  are elongated. Further, strains to which four of the piezoelectric oscillators contribute are the same since four of them are laminated in a direction orthogonal to a displacement direction. Accordingly, the piezoelectric oscillator  11  carries out bending vibration in the horizontal direction. 
     That is, all of four of the piezoelectric oscillators  11  carry out bending oscillation in the same direction since the same drive signals are inputted to the same polarized regions. Therefore, large bending vibration is produced in the piezoelectric element  10 . Further, only the bending vibration is excited in the piezoelectric oscillator  11  different from the conventional examples shown by FIG. 13 a  and  13   b.    
     Further, the electrode  16   f  substantially covers the top face of the polarized region  12   a  of the piezoelectric oscillator  12  and a portion thereof is drawn to the side face  10   b.  That is, all of top faces of the polarized regions  12   a  of four sheets of the piezoelectric oscillators  12  are brought into the same potential by the electrode  16   f  continuous thereto via portions thereof drawn to the side face  10   b.    
     Similarly, the electrode  16   g  substantially covers other face of the polarized region  12   a  of the piezoelectric oscillator  12  and a portion thereof is drawn to the side face  10   a.  That is, other faces of the polarized regions  12   a  of the four sheets of the piezoelectric oscillators  12  are brought into the same potential by the electrode  16   g  continuous thereto via portions thereof drawn to the side face  10   a.    
     Further, when in the piezoelectric oscillator  12 , with the electrode  16   g  as a reference, a drive signal is inputted to the electrode  16   f,  the polarized region  12   a  is elongated or contracted and accordingly, the piezoelectric oscillator  12  carries out elongation and contraction movement in the longitudinal direction. 
     That is, four sheets of the piezoelectric oscillators  12  carry out the same elongation and contraction vibration since the same drive signals are inputted to the same polarized regions. Accordingly, large elongation and contraction vibration is produced in the piezoelectric element  10 . 
     Next, an explanation will be given of an example of fabrication procedure of the piezoelectric element  10 . 
     First, a piezoelectric ceramics powder mixed with predetermined materials by predetermined rates, is kneaded by mixing an organic solvent or the like as necessary and is formed to be a predetermined shape and calcined. The condition of calcination is substantially the same as that in fabricating normal piezoelectric ceramics. 
     Next, one face of the calcined piezoelectric ceramics is coated with conductive paste for electrode by dividing it to correspond to the respective polarized regions. That is, a first one of a piece of the piezoelectric ceramics for constituting the piezoelectric oscillator  11  or  18  is coated therewith in four divisions, a second one thereof is coated therewith substantially over an entire face except a peripheral portion thereof, thereafter, a third one thereof, a fourth one thereof . . . are coated with electrodes which are alternately different from each other. A first one, a second one ... each of one face of a piece of the piezoelectric ceramics for constituting the piezoelectric oscillator  12 , are alternately coated with the electrodes  16   f  and  16   g.    
     Next, a total of five sheets of pieces of the piezoelectric ceramics for constituting the piezoelectric oscillators  11  and  13  and coated with the conductive paste for electrode, are laminated, on top thereof, four sheets of pieces of the piezoelectric ceramics for constituting the piezoelectric oscillators  12  and coated with the conductive paste for electrode, are laminated and thereafter, regular burning is carried out in respect thereof. The condition of the regular burning is substantially the same as that in fabricating normal piezoelectric ceramics. By the regular burning, the piezoelectric oscillators  11 , the piezoelectric oscillator  18  and the piezoelectric oscillators  12  are integrally formed. 
     Next, by coating and drying paste for electrode at predetermined positions of side faces of the pieces of the piezoelectric ceramics which have been regularly burnt, the electrodes  16   a,    16   b,    16   c,    16   d,    16   e,    16   f  and  16   g  are formed in a predetermined structure. Therefore, the coupling faces of the respective piezoelectric oscillators constitute common electrodes. 
     Next, by applying predetermined voltages on the electrodes  16   a,    16   b,    16   c  and  16   d  with the electrode  16   e  as a reference and on the electrode  16   f  with the electrode  16   g  as a reference, the polarized regions  11   a ,  11   b ,  11   c,    11   d,  lie,  12   a  and  12   b  are polarized in predetermined directions to thereby finish the piezoelectric element  10 . At this occasion, the intermediary piezoelectric oscillator  18  is not applied with voltage and therefore, the polarizing treatment is not carried out. Further, the piezoelectric oscillator  18  serves as an insulating member between the piezoelectric oscillators  11  and  12 . Incidentally, the insulating member  18  may use other material regardless of the piezoelectric oscillator. 
     An explanation will be given of operation of the ultrasonic motor  1  having the above-described structure in reference to FIGS. 4 a,    4   b,    4   c  and  4   d  and FIGS. 5 a,    5   b,    5   c  and  5   d.    
     FIG. 4 b  and FIG. 5 b  are view showing a connecting structure of the ultrasonic motor  1  and an alternating current power source (signal source)  6 . 
     That is, in the ultrasonic motor  1 , the electrode  16   e  and the electrodes  16   a,    16   b,    16   c  and  16   d  of the piezoelectric oscillator  11  are respectively connected to the alternating current power source  6  via switches  17   a  and  17   b  (switching means). Further, the electrode  16   f  of the piezoelectric oscillator  12  is directly connected to the output side of the alternating current power source  6  and the electrode  16   g  thereof is directly connected to the reference potential side, respectively. 
     Therefore, connecting directions of the electrodes  16   a,    16   b,    16   c,    16   d  and  16   e,  that is, whether these electrodes are connected to the output side of the alternating current power source  6  or to the ground potential side thereof, is switched by the switch  17   a  and the switch  17   b.    
     Further, in FIGS. 4 a,    4   b,    4   c  and  4   d  and FIGS. 5 a,    5   b ,  5   c  and  5   d,  constituent elements of the ultrasonic motor  1  other than the piezoelectric element  10 , are omitted for convenience of explanation, further, in these drawings, for convenience of explanation, the piezoelectric element  10  is provided with a structure in which one sheet of the piezoelectric oscillator  11  and the one sheet of the piezoelectric oscillator  12  are integrally laminated by interposing the insulating member  18 . 
     First, an explanation will be given of operation of the ultrasonic motor  1  when the electrodes  16   a ,  16   b ,  16   c  and  16   d  are connected to the output side and the electrode  16   e  is connected to the ground potential side via the switch  17   a  and the switch  17   b  as shown by FIG. 4 b,  in reference to FIGS. 4 a,    4   c  and  4   d.    
     FIG. 4 a  shows a behavior of elongation and contraction vibration of the piezoelectric oscillator  12 , FIG. 4 c  shows a behavior of bending vibration of the piezoelectric oscillator  11 , respectively, by top views and FIG. 4 d  shows a drive state of the ultrasonic motor  1  when viewed from above. 
     When output potential of the alternating current power source  6  becomes higher than the reference potential, the polarized region  11   a  and the polarized region  11   d  of the piezoelectric oscillator  11  are elongated in the longitudinal direction and the polarized region  11   b  and the polarized region  11   c  are contracted in the longitudinal direction. Accordingly, the piezoelectric oscillator  11  is bent as shown by void portions of FIG. 4 c  and the end face is inclined in a direction designated by an arrow mark Y. 
     At this occasion, as mentioned above, substantially an entire face of the piezoelectric oscillator  12  is polarized in a direction the same as that of the polarized region  11   a  and accordingly, as shown by void portions of FIG. 4 a,  the piezoelectric oscillator  12  is elongated in the longitudinal direction and the end face is elongated in a direction designated by an arrow mark X. 
     Further, when the output potential of the alternating current power source  6  becomes lower than the reference potential, the end face of the piezoelectric oscillator  11  is inclined in a direction of an arrow mark Y′ contrary to the arrow mark Y, further, the end face of the piezoelectric oscillator  12  is contracted in a direction reverse to the arrow mark X by 180 degree. 
     That is, the bending vibration produced in the piezoelectric oscillator  11  and the elongation and contraction vibration produced at the piezoelectric oscillator  12  are synthesized, as a result, the end face of the piezoelectric element  10  carries out an elliptic motion in a direction shown by an arrow mark Z of FIG. 4 d , therefore, the ultrasonic motor  1  moves a moving body (illustrated is omitted) which is brought into press contact with the end face in the direction designated by the arrow mark Z. 
     Next, an explanation will be given of the operation of the ultrasonic motor  1  when contrary to FIG. 4, the electrodes  16   a ,  16   b ,  16   c  and  16   d  are connected to the reference potential side and the electrode  16   e  is connected to the output side as shown by FIG. 5 b,  in reference to FIG. 5 a,    5   c  and  5   d.    
     FIG. 5 a  shows the behavior of the elongation and contraction vibration of the piezoelectric oscillator  12  and FIG. 5 c  shows the behavior of the bending vibration of the piezoelectric oscillator  11 , respectively by using top views and FIG. 5 d  shows the drive state of the ultrasonic motor  1  when viewed from above. 
     When the output potential of the alternating current power source  6  becomes higher than the reference potential, the polarized region  11   a  and the polarized region  11   d  of the piezoelectric oscillator  11  are contracted in the longitudinal direction and the polarized region  11   b  and the polarized region  11   c  are elongated in the longitudinal direction. Accordingly, the piezoelectric oscillator  11  is bent as shown by void portions of FIG. 5 c  and the end face is inclined in a direction designated by an arrow mark Y′. 
     At this occasion, as mentioned above, substantially the entire face of the piezoelectric oscillator  12  is polarized in the direction the same as that of the polarized region  11   a  and accordingly, the piezoelectric oscillator  12  is elongated in the longitudinal direction as shown by void portions of FIG. 5 a  and the end face is elongated in the direction designated by the arrow mark X. 
     Further, when the output potential of the alternating current power source  6  becomes lower than the reference potential, the end face of the piezoelectric oscillator  11  is inclined in the direction of the arrow mark Y contrary to the arrow mark Y′, further, the end face of the piezoelectric oscillator  12  is contracted in the direction reverse to the arrow mark X by 180 degree. 
     Therefore, the end face of the piezoelectric oscillator  10  carries out the elliptic motion in a direction designated by an arrow mark Z′ of FIG. 5 d,  accordingly, the ultrasonic motor  1  moves a moving body (illustration is omitted) which is brought into press contact with the end face in the direction designated by the arrow mark Z′, that is, in a direction reverse to the arrow mark Z of FIG. 4 d.    
     That is, the electrode  16   e  of the piezoelectric oscillator  11  of the ultrasonic motor  1  is connected to the alternating current power source  6  via the switch  17   a,  further, the electrodes  16   a ,  16   b ,  16   c  and  16   d  are connected thereto via the switch  17   b,  respectively, and therefore, by only switching both of the switches  17   a  and  17   b,  the direction in which the ultrasonic motor  1  moves the moving body  14   a  can be reversed. 
     In this way, according to the ultrasonic motor  1  of the first embodiment of the invention, the piezoelectric oscillators  12  as the elongation and contraction vibration source are integrally laminated on the piezoelectric oscillators  11  as the bending vibration source and therefore, for example, by separately setting and changing the reference potential of the piezoelectric oscillators  11  and the reference potential of the piezoelectric oscillators  12 , the elongation and contraction vibration and the bending vibration can separately be controlled. 
     Further, the bending vibration is carried out by inputting drive signals from the alternating current power source  6  to all of the polarized regions  11   a,    11   b,    11   c  and  11   d  of the piezoelectric oscillators  11  and accordingly, only the bending vibration is excited and further, the drive force is large and the output of the ultrasonic motor  1  is larger than that of the conventional ultrasonic motor. 
     Further, pluralities of the piezoelectric oscillators  11  and the piezoelectric oscillators  12  are respectively used and accordingly, the output is further magnified. 
     Further, the ultrasonic motor  1  is driven by a single one of the input signal and accordingly, the constitution of the self-excited oscillation circuit is simplified and the self-excited oscillation control is facilitated. 
     Further, when the electrode  16   e  of the piezoelectric oscillator  11  is connected to the alternating current power source  6  via the switch  17   a  and the electrodes  16   a ,  16   b ,  16   c  and  16   d  are connected thereto via the switch  17   b,  respectively, by only switching both of the switches  17   a  and  17   b,  the ultrasonic motor  1  moves the moving body  14   a  in the reverse direction. 
     It goes without saying that the ultrasonic motor  1  can be driven even when the piezoelectric oscillators  11  and  12  are applied with signals having different phases, for example, signals of 90 degree or −90 degree. 
     Further, although according to the embodiment, in the piezoelectric element  10 , four sheets of the piezoelectric oscillators  11  are integrally laminated, on top thereof, four sheets of the piezoelectric oscillators  12  are integrally laminated, the invention is not limited thereto but there may be constructed a structure in which the piezoelectric oscillators  11  and the piezoelectric oscillators  12  are laminated alternately and integrally. Further, numbers of sheets of the piezoelectric oscillators  11  and  12  may naturally be set arbitrarily and both need not to be the same. Particularly, by making the numbers different from each other, the two vibration forces can be controlled independently from each other and therefore, a ratio of the numbers of sheets is determined in accordance with the required specification of the motor. 
     Further, the electrodes  16   a ,  16   b ,  16   c  and  16   d  need not to be separate but even when they are shortcircuited as single ones of the electrodes, the ultrasonic motor  1  is operated with no problem. 
     Further, although the electrode  16   e  of the piezoelectric oscillator  11  is connected to the alternating current power source  6  via the switch  17   a  and the electrodes  16   a ,  16   b ,  16   c  and  16   d  are connected thereto via the switch  17   b,  the invention is not limited thereto but contrary to the embodiment, the electrodes  16   a ,  16   b ,  16   c  and  16   d  of the piezoelectric oscillator  11  may directly be connected to one side of the alternating current power source  6  and the electrode  16   e  may directly be connected thereto respectively without interposing switches, further, the electrode  16   f  and the electrode  16   g  of the piezoelectric oscillator  12  may be connected to the alternating current power source  6  via the switch  17   a  and the switch  17   b.    
     Second Embodiment 
     An explanation will be given of an ultrasonic motor  2  according to a second embodiment of the invention. 
     As shown by a front view of FIG. 6, the ultrasonic motor  2  is constituted by a piezoelectric element  20 , a supporting member  23  for supporting the piezoelectric element  20  and an object portion  24  including a moving body  24   a  which is brought into contact with an end face of the piezoelectric element  20  and moved by the piezoelectric element  20 . That is, the ultrasonic motor  2  is a ultrasonic motor which moves the moving body  24   a  in a direction in parallel with the laminated layer faces of the piezoelectric element  20 . 
     Further, the piezoelectric element  20  is pressed to the moving body  24   a  by a force from a pressing mechanism (illustration is omitted) having, for example, an elastic member of the like via the supporting member  23 . 
     The piezoelectric element  20  is constructed by a structure in which, for example, respective four sheets of piezoelectric oscillators  21  (first piezoelectric oscillators) as a bending oscillation source and piezoelectric oscillators  22  (second piezoelectric oscillators) as an elongation and contraction vibration source overlap each other, further, the both are overlapped to laminate integrally, further, a lower face thereof is installed with projections  25  for driving the moving body  24   a  by being brought into contact therewith. 
     Further, the piezoelectric element  20  is provided with electrodes (illustration is omitted in FIG.  6 ), mentioned later. Further, according to the piezoelectric oscillators  21  and  22 , for example, by interposing insulating members  28  (illustration is omitted), insulation among contiguous piezoelectric oscillators or electrodes is ensured. 
     Further, the projections  25  are respectively installed at portions in correspondence with antinodes of the bending vibration produced in the piezoelectric oscillator  21 . 
     Here, an explanation will be given of polarized states of the piezoelectric oscillators  21  and the piezoelectric oscillators  22  and the structure of the electrodes of the piezoelectric element  20  in reference to FIGS. 7 a ,  7   b ,  7   c ,  7   d,    7   e  and  7   f.    
     FIG. 7 a  is a view showing a side face  20   a  of the piezoelectric element  20  and FIG. 7 f  is a view showing a side face  20   b  disposed on a side opposed to the side face  20   a.  FIG. 7 b  is a view showing one face of the piezoelectric oscillator  21  and FIG. 7 c  is a view showing other face of the piezoelectric oscillator  21 . Further, FIG. 7 d  is a view showing one face of the piezoelectric oscillator  22  and FIG. 7 e  is a view showing other face of the piezoelectric oscillator  22 . Further, in the drawings, illustration of the projections  25  is omitted. 
     First, an explanation will be given of polarized states of the piezoelectric oscillator  21  and the piezoelectric oscillator  22 . 
     The piezoelectric oscillator  21  is constructed by a structure in which as shown by FIG. 7 b  and FIG. 7 c , four of a polarized region  21   a,  a polarized region  21   b,  a polarized region  21   c  and a polarized region  21   d  which are formed by being divided in four in the vertical direction, are polarized in a laminating direction, alternately reversely. That is, the polarized region  21   a  and the polarized region  21   c  are brought into a state in which, for example, upper faces thereof become plus and the polarized region  21   b  and the polarized region  21   d  are brought into a state in which, for example, upper faces thereof become minus. 
     Further, as shown by FIG. 7 d  and FIG. 7 e,  the piezoelectric oscillator  22  is polarized such that substantially an entire face thereof constitutes a single one of a polarized region and in the laminating direction, for example, an upper face thereof becomes plus. 
     Next, an explanation will be given of the structure of the electrodes of the piezoelectric element  20 . 
     As shown by FIGS. 7 a ,  7   b ,  7   c ,  7   d,    7   e  and  7   f,  the piezoelectric element  20  is provided with an electrode  26   a , an electrode  26   b , an electrode  26   c , and electrode  26   d,  an electrode  26   e,  an electrode  26   f  and an electrode  26   g.    
     Among them the electrodes  26   a ,  26   b,    26   c,    26   d  and  26   e  are electrodes for inputting signals to the piezoelectric oscillator  21  and the electrodes  26   f  and  26   g  are electrodes for inputting signals to the piezoelectric oscillator  22 . 
     The electrode  26   a  substantially covers an upper face of the polarized region  21   a  of the piezoelectric oscillator  21  and a portion thereof is drawn to the side face  20   a . That is, all of faces on one side of the polarized regions  21   a  of the four sheets of the piezoelectric oscillators  21  become the same potential by the electrode  26   a  continuous thereto via portions drawn to the side face  20   a.    
     Similarly, the electrode  26   b  substantially covers one face of the polarized region  21   b  of the piezoelectric oscillator  21  and a portion thereof is drawn to the side face  20   b.  That is, all of faces on one side of the polarized regions  21   b  of four sheets of the piezoelectric oscillators  21  become the same potential by the electrode  26   b  continuous thereto via portions thereof drawn to the side face  20   b.    
     Further, the electrode  26   c  substantially covers one face of the polarized region  21   c  of the piezoelectric oscillator  21  and a portion thereof is drawn to the side face  20   b.  That is, all of faces on one side of the polarized regions  21   c  of four sheets of the piezoelectric oscillators  21  become the same potential by the electrode  26   c  continuous thereto via portions thereof drawn to the side face  20   b.    
     Similarly, the electrode  26   d  substantially covers one face of the polarized region  21   d  of the piezoelectric oscillator  21  and a portion thereof is drawn to the side face  20   a.  That is, all of faces on one side of the polarized regions  21   d  of four sheets of the piezoelectric oscillators  21  become the same potential by the electrode  26   d  continuous thereto via portions thereof drawn to the side face  20   a.    
     Further, the electrode  26   e  covers all of lower faces of four of the polarized regions  21   a,    21   b,    21   c  and  21   d  of the piezoelectric oscillator  21  and a portion thereof is drawn to the side face  20   a.  That is, all of other faces of four of the polarized regions of four sheets of the piezoelectric oscillators  21  become the same potential by the electrode  26   e  continuous thereto via portions thereof drawn to the side face  20   a.    
     Therefore, according to the piezoelectric oscillator  21 , in the case in which the same drive signal is inputted to the electrodes  26   a ,  26   b ,  26   c  and  26   d  with the electrode  26   e  as the reference electrode, when the polarized regions  21   a  and  21   c  are elongated, the polarized regions  21   b  and  21   d  are contracted, further, when the polarized regions  21   a  and  21   d  are conversely contracted, the polarized regions  21   b  and  21   c  are elongated. Accordingly, the piezoelectric oscillator  21  carries out bending vibration in the thickness direction. 
     That is, the same drive signals are inputted to the same polarized regions and accordingly, all of four of the piezoelectric oscillators  21  carry out the bending vibration in the same direction. Accordingly, large bending vibration is produced in the piezoelectric element  20 . 
     Further, the electrode  26   f  substantially covers one face of a polarized region  22   a  of the piezoelectric oscillator  22  and a portion thereof is drawn to the side face  20   b.  That is, all of faces on one side of the polarized regions  22   a  of four sheets of the piezoelectric oscillators  22  become the same potential by the electrode  26   f  continuous thereto via portions thereof drawn to the side face  20   b.    
     Similarly, the electrode  26   g  substantially covers other face of the polarized region  22   a  of the piezoelectric oscillator  22  and a portion thereof is drawn to the side face  20   a.  That is, all of lower faces of the polarized region  22   a  of four sheets of the piezoelectric oscillators  22  become the same potential by the electrode  26   g  continuous thereto via portions thereof drawn to the side face  20   a.    
     Therefore, according to the piezoelectric oscillator  22 , when the drive signal is inputted to the electrode  26   f  with the electrode  26   g  as a reference, the polarized region  22   a  is elongated or contracted. Therefore, the piezoelectric oscillator  22  carries out elongation and contraction movement in the longitudinal direction. Accordingly, large elongation and contraction vibration is produced in the piezoelectric element  20 . 
     That is, the same drive signals are inputted to the same polarized regions and accordingly, four sheets of the piezoelectric oscillators  22  carry out the same elongation and contraction vibration. 
     Further, fabrication procedure of the ultrasonic motor  2  is the same as the fabrication procedure of the ultrasonic motor  1 . 
     An explanation will be given of operation of the ultrasonic motor  2  having the above-described structure in reference to FIGS. 8 a,    8   b,    8   c  and  8   d  and FIGS. 9 a,    9   b,    9   c  and  9   d.    
     FIG. 8 c  and FIG. 9 c  are views showing a connecting structure of the ultrasonic motor  2  and the alternating current power source  6 . 
     That is, according to the ultrasonic motor  2 , the electrode  26   e  and the electrodes  26   a ,  26   b ,  26   c  and  26   d  of the piezoelectric oscillator  21  are respectively connected to the alternating current power source  6  via switches  27   a  and  27   b  (switching means). Further, the electrode  26   f  of the piezoelectric oscillator  22  is directly connected to the output side of the alternating current power source  6  and the electrode  26   g  thereof is directly connected to the reference potential side, respectively. 
     Therefore, the directions for connecting the electrodes  26   a ,  26   b ,  26   c ,  26   d  and  26   e,  that is, whether these electrodes are connected to the output side of the alternating current power source  6  or to the ground potential side, is switched by the switch  27   a  and the switch  27   b.    
     Further, in FIGS. 8 a,    8   b,    8   c  and  8   d  and FIGS. 9 a,    9   b,    9   c  and  9   d,  constituent elements of the ultrasonic motor  2  other than the piezoelectric element  20  are omitted for convenience of explanation, further, the piezoelectric element  20  is constructed by a structure in which one sheet of the piezoelectric oscillator  21  and one sheet of the piezoelectric oscillator  22  are integrally laminated by interposing an insulating member  28 . 
     First, an explanation will be given of operation of the ultrasonic motor  2  when the electrodes  26   a ,  26   b ,  26   c  and  26   d  are connected to the ground potential side and the electrode  26   e  is connected to the output side via the switch  27   a  and the switch  27   b  as shown by FIG. 8 c,  in reference to FIGS. 8 a  and  8   b.    
     FIG. 8 a  shows a behavior of elongation and contraction vibration of the piezoelectric oscillator  22  and FIG. 8 b  shows a behavior of bending vibration of the piezoelectric oscillator  21  respectively by using sectional views and FIG. 8 d  shows a drive state of the ultrasonic motor  2  when viewed from a transverse direction. 
     When output potential of the alternating current power source  6  becomes higher than reference voltage, the polarized region  21   a  and the polarized region  21   c  of the piezoelectric oscillator  21  are elongated in the longitudinal direction and the polarized region  21   b  and the polarized region  21   d  are contracted in the longitudinal direction. Accordingly, the piezoelectric oscillator  21  is bent as shown by a hatched portion of FIG. 8 b  and predetermined portions of a lower face thereof are bent in directions designated by arrow marks Y. 
     At this occasion, as mentioned above, substantially an entire face of the piezoelectric oscillator  22  is polarized in a direction the same as that of the polarized region  21   a  and accordingly, the piezoelectric oscillator  22  is elongated in the longitudinal direction as shown by a hatched portion of FIG. 8 a  and a lower face thereof is elongated in directions designated by arrow marks X. 
     Further, when the output potential of the alternating current power source  6  becomes lower than the reference potential, predetermined portions of the lower face of the piezoelectric oscillator  21  are bent in directions of arrow marks Y′ reverse to the arrow mark Y, further, the lower face of the piezoelectric oscillator  22  is contracted in directions 180 degree reverse to the arrow marks X. 
     Accordingly, the predetermined portions of the lower face of the piezoelectric oscillator  20  carry out an elliptic motion in directions designated by arrow marks Z of FIG. 8 d , therefore, the ultrasonic motor  2  moves a moving body (illustration is omitted) which is brought into press contact with the end face in directions designated by the arrow marks Z. 
     Next, an explanation will be given of the operation of the ultrasonic motor  2  when as shown by FIG. 9 c , contrary to FIG. 8, the electrodes  26   a ,  26   b ,  26   c  and  26   d  are connected to the output side and the electrode  26   e  is connected to the reference potential side in reference to FIGS. 9 a,    9   b  and  9   d.    
     FIG. 9 a  shows a behavior of elongation and contraction vibration of the piezoelectric oscillator  22  and FIG. 9 c  shows a behavior of bending vibration of the piezoelectric oscillator  21  respectively by using sectional views, further, FIG. 9 d  shows a drive state of the ultrasonic motor  2  when viewed from a transverse direction. 
     When the output potential of the alternating current power source  6  becomes higher than the reference potential, the polarized region  21   a  and the polarized region  21   d  of the piezoelectric oscillator  21  are contracted in the longitudinal direction and the polarized region  21   b  and the polarized region  21   c  are elongated in the longitudinal direction. Accordingly, the piezoelectric oscillator  21  is bent as shown by a hatched portion of FIG. 9 b  and predetermined portions of the lower face are bent in directions shown by arrow marks Y′. 
     At this occasion, as mentioned above, substantially an entire face of the piezoelectric oscillator  22  is polarized in a direction the same as that of the polarized region  21   a  and accordingly, as shown by a hatched portion of FIG. 9 a , the piezoelectric oscillator  22  is elongated in the longitudinal direction and the end face is elongated in directions shown by arrow marks X. 
     Further, when the output potential of the alternating current power source  6  becomes lower than the reference potential, the predetermined portions of the lower face of the piezoelectric oscillator  21  are bent in a direction of arrow marks Y reverse to the arrow marks Y′, further, the lower face of the piezoelectric oscillator  22  is contracted in directions 180 degree reverse to the arrow marks X. 
     Accordingly, the predetermined portions of the lower face of the piezoelectric element  20  carry out an elliptic motion in a direction shown by arrow marks Z′ of FIG. 9 d,  and therefore, the ultrasonic motor  2  moves a moving member (illustration is omitted) which is brought into press contact with the end face in the direction shown by the arrow mark Z′, that is, in the direction reverse to the arrow mark Z of FIG. 8 d.    
     That is, according to the ultrasonic motor  2 , the electrode  26   e  of the piezoelectric oscillator  21  is connected to the alternating current power source  6  via the switch  27   a , the electrodes  26   a ,  26   b ,  26   c  and  26   d  are connected thereto via the switch  27   b , respectively, and accordingly, the moving direction of the moving body  24   a  can be reversed simply by switching both of the switches  27   a  and  27   b  without providing a phase circuit for changing a phase of a signal. 
     In this way, according to the ultrasonic motor  2  of the second embodiment of the invention, the piezoelectric oscillators  22  as an elongation and contraction vibration source are integrally laminated on the piezoelectric oscillators  21  as a bending vibration source and therefore, for example, by separately setting and changing reference potential of the piezoelectric oscillator  21  and the reference potential of the piezoelectric oscillator  22 , the elongation and contraction vibration and the bending vibration can separately be controlled. 
     Further, the bending vibration is carried out by inputting drive signals to all of the polarized regions  21   a,    21   b,    21   c  and  21   d  of the piezoelectric oscillator  21  and accordingly, output of the ultrasonic motor  2  is larger than that of the conventional ultrasonic motor. 
     Further, respective pluralities of the piezoelectric oscillators  21  and the piezoelectric oscillators  22  having thin thicknesses are used and accordingly, the piezoelectric oscillators can be driven by low voltage and the output is further magnified. 
     Further, the ultrasonic motor  2  is driven by a single one of an input signal and accordingly, a self-excited oscillation circuit can easily be constituted. 
     Further, when the electrode  26   e  of the piezoelectric oscillator  21  is connected to the alternating current power source  6  via the switch  27   a  and the electrodes  26   a ,  26   b ,  26   c  and  26   d  are connected thereto via the switch  27   b , respectively, the ultrasonic motor  2  moves the moving body  24   a  in the reverse direction simply by switching both of the switches  27   a  and  27   b.    
     Even when the piezoelectric oscillators  21  and  22  are applied with signals having different phases, the piezoelectric oscillators can naturally be driven. 
     Further, according to the piezoelectric element  20  of the embodiment, numbers of sheets of the piezoelectric oscillators  21  and  22  may arbitrarily be set and both need not to be the same. 
     Further, the electrodes  26   a ,  26   b ,  26   c  and  26   d  need not to be separate but even when the electrodes are shortcircuited into one constituent, the ultrasonic motor  2  is operated with no problem. 
     Further, although the electrode  26   e  of the piezoelectric oscillator  21  is connected to the alternating current power source  6  via the switch  27   a  and the electrodes  26   a ,  26   b ,  26   c  and  26   d  are connected thereto via the switch  27   b , respectively, the invention is not limited thereto but, contrary to the embodiment, the electrodes  26   a ,  26   b ,  26   c  and  26   d  of the piezoelectric oscillator  21  may directly be connected to one side of the alternating current power source  6  and the electrode  26   e  may directly be connected to other side thereof respectively without interposing switches, further, the electrode  26   f  and the electrode  26   g  of the piezoelectric oscillator  22  may be connected to the alternating current power source  6  via the switch  27   a  and the switch  27   b.    
     Third Embodiment 
     An explanation will be given of a third embodiment of the invention in reference to FIG. 10 a  through FIG. 11 as follows. 
     The third embodiment of the invention is basically the same as the first embodiment and the second embodiment and comprises piezoelectric oscillators  31  (first piezoelectric oscillators) as a bending vibration source and piezoelectric oscillators  32  (second piezoelectric oscillators) as an elongation and contraction vibration source. A point of difference therebetween resides in that the piezoelectric oscillator  18  constituting an insulating member is not provided and the piezoelectric oscillators  31  and the piezoelectric oscillators  32  are provided with common electrodes  36   e.    
     An explanation will be given of polarized states and electrode structures based on a modified example of the first embodiment as follows. 
     FIG. 10 a  is a view showing a side face  30   a  of a piezoelectric element  30  and FIG. 10 f  is a view showing a side face  30   b  thereof. FIG. 10 b  is a top view of odd number ones of the piezoelectric oscillators  31  and a bottom view of even number ones thereof and FIG. 10 c  is a bottom view of the odd number ones of the piezoelectric oscillators  31  and a top view of even number ones thereof. Further, FIG. 10 d  is a top view of odd number ones of the piezoelectric oscillators  32  and a bottom view of even number ones thereof and FIG. 10 e  is a bottom view of the odd number ones of the piezoelectric oscillators  32  and a top view of even number ones thereof. That is, coupling faces of the respective piezoelectric oscillators constitute common electrodes. 
     First, an explanation will be given of polarized states of the piezoelectric oscillator  31  and the piezoelectric oscillator  32 . 
     As shown by FIG. 10 b  and FIG. 10 c,  the piezoelectric oscillator  31  is constituted by a structure in which four of a polarized region  31   a,  a polarized region  31   b,  a polarized region  31   c  and a polarized region  31   d  produced by dividing the piezoelectric oscillator  31  in two in the longitudinal direction and dividing the piezoelectric oscillator  31  in two also in the transverse direction, are polarized alternately reversely in a laminating direction. That is, the polarized region  31   a  and the polarized region  31   d  are brought into a state in which, for example, upper faces thereof become plus and the polarized region  31   b  and the polarized region  31   c  are brought into a state in which, for example, upper face thereof become minus. 
     Further, as shown by FIG. 10 d  and FIG. 10 e , substantially an entire face of the piezoelectric oscillator  32  constitutes a single one of the polarized region and the piezoelectric oscillator  32  is polarized in the laminating direction such that, for example, an upper face thereof becomes plus. 
     Next, an explanation will be given of the structures of electrodes of the piezoelectric element  30  in reference to FIGS. 10 a ,  10   b,    10   c ,  10   d ,  10   e  and  10   f  as follows. 
     The piezoelectric element  30  is provided with an electrode  36   a , an electrode  36   b , an electrode  36   c , an electrode  36   d , an electrode  36   e  and an electrode  36   f.    
     Among them, the electrodes  36   a ,  36   b ,  36   c ,  36   d  and  36   e  are electrodes for inputting signals to the piezoelectric oscillator  31  and the electrodes  36   e  and  36   f  are electrodes for inputting signals to the piezoelectric oscillator  32 . Accordingly, the electrode  36   e  constitutes an electrically common portion of the piezoelectric oscillators  31  and the piezoelectric oscillators  32 . 
     The electrode  36   a  substantially covers one face of the polarized region  31   a  of the piezoelectric oscillator  31  and a portion thereof is drawn to the side face  30   a.  That is, all of upper faces of the polarized regions  31   a  of four sheets of the piezoelectric oscillators  31  become the same potential by the electrode  36   a  continuous thereto via portions thereof drawn to the side face  30   a.    
     Similarly, the electrode  36   b  substantially covers one face of the polarized region  31   b  of the piezoelectric oscillator  31  and a portion thereof is drawn to the side face  30   a.  That is, all of upper faces of the polarized regions  31   b  of four sheets of the piezoelectric oscillators  31  become the same potential by the electrode  36   b  continuous thereto via portions thereof drawn to the side face  30   a.    
     Further, the electrode  36   c  substantially covers one face of the polarized region  31   c  of the piezoelectric oscillator  31  and a portion thereof is drawn to the side face  30   b.  That is, all of faces on one side of the polarized regions  31   c  of four sheets of the piezoelectric oscillators  31  become the same potential by the electrode  36   c  continuous thereto via portions thereof drawn to the side face  30   b.    
     Similarly, the electrode  36   d  substantially covers one face of the polarized region  31   d  of the piezoelectric oscillator  31  and a portion thereof is drawn to the side face  30   b.  That is, all of faces on one side of the polarized regions  31   d  of four sheets of the piezoelectric oscillators  31  become the same potential by the electrode  36   d  continuous thereto via portions thereof drawn to the side face  30   b.    
     Further, the electrode  36   e  covers other faces of four of the polarized regions  31   a,    31   b,    31   c  and  31   d  of the piezoelectric oscillator  31  and other face of a polarized region  32   a  of the piezoelectric oscillator  32  and portions thereof are drawn to the side face  30   a.  That is, all of the other faces of four of the polarized regions of four sheets of the piezoelectric oscillators  31  and faces on one side of four sheets of the piezoelectric oscillators  32  become the same potential by the electrode  36   e  continuous thereto via portions thereof drawn to the side face  30   a.    
     Further, according to the piezoelectric oscillator  31 , in the case in which the same drive signal is inputted to the electrodes  36   a ,  36   b ,  36   c  and  36   d  with the electrode  36   e  as a reference electrode, when the polarized regions  31   a  and  31   d  are elongated, the polarized regions  31   b  and  31   c  are contracted, further, when the polarized regions  31   a  and  31   d  are conversely contracted, the polarized regions  31   b  and  31   c  are elongated. Accordingly, the piezoelectric oscillator  31  carries out bending vibration in the transverse direction. 
     That is, the same drive signals are inputted to the same polarized regions and accordingly, all of four of the piezoelectric oscillators  31  carry out the bending vibration in the same direction. Further, the piezoelectric oscillators  31  are laminated in a direction orthogonal to a displacement direction and therefore, strains to which four of the piezoelectric oscillators contribute are the same. Accordingly, the large bending oscillation is produced in the piezoelectric element  30 . Further, only bending vibration is excited in the piezoelectric oscillator  31  different from the conventional examples shown by FIGS. 13 a  and  13   b.    
     Further, the electrode  36   f  substantially covers an upper face of the polarized region  32   a  of the piezoelectric oscillator  32  and a portion thereof is drawn to the side face  30   b.  That is, all of upper faces of the polarized regions  32   a  of four sheets of the piezoelectric oscillators  32  become the same potential by the electrode  36   f  continuous thereto via portions thereof drawn to the side face  30   b.    
     Further, according to the piezoelectric oscillator  32 , when a drive signal is inputted to the electrode  36   f  with the electrode  36   e  as a reference, the polarized region  32   a  is elongated or contracted and accordingly, the piezoelectric oscillator  32  carries out elongation and contraction movement in the longitudinal direction. 
     That is, the same drive signals are inputted to the same polarized regions and accordingly, four sheets of the piezoelectric oscillators  32  carry out the same elongation and contraction vibration. Therefore, large elongation and contraction vibration is produced in the piezoelectric element  30 . 
     An explanation will be given of operation of the ultrasonic motor  3  having the above-described structure in reference to FIG.  11 . 
     FIG. 11 is a view showing a connecting structure of the ultrasonic motor  3  and the alternating current power source (signal source)  6 . 
     That is, according to the ultrasonic motor  3 , the electrodes  36   a ,  36   b ,  36   c  and  36   d  of the piezoelectric oscillator  31  are respectively connected to the alternating current power source  6  via a phase inverter circuit  19 . Further, the electrode  36   f  of the piezoelectric oscillator  32  is directly connected to the output side of the alternating current power source  6  and the electrode  36   e  is directly connected to a reference potential side thereof, respectively. Therefore, a phase of a signal inputted to the electrodes  36   a ,  36   b ,  36   c  and  36   d  is changed by the phase inverter circuit  19  relative to the electrode  36   f.    
     Further, in FIG. 11, constituent elements of the ultrasonic motor  3  other than the piezoelectric element  30  are omitted for convenience of explanation, further, in this case, for convenience of explanation, the piezoelectric element  30  is constructed by a structure in which one sheet of the piezoelectric oscillator  31  and one sheet of the piezoelectric oscillator  32  are integrally laminated. 
     When the phase of the signal from the alternating current power source  6  is not inverted by the phase inverter circuit  19 , the ultrasonic motor  3  shows a drive state similar to that in FIGS. 4 a,    4   b,    4   c  and  4   d.    
     That is, when the output potential of the alternating current power source  6  becomes higher than the reference potential, the polarized region  31   a  and the polarized region  31   d  of the piezoelectric oscillator  31  are elongated in the longitudinal direction and the polarized region  31   b  and the polarized region  31   c  are contracted in the longitudinal direction. Accordingly, the piezoelectric oscillator  31  is bent as shown by the void portions of FIG. 4 c  and the end face is inclined in the direction designated by the arrow mark Y. 
     At this occasion, as mentioned above, almost entire face of the piezoelectric oscillator  32  is polarized in the direction the same as that of the polarized region  31   a  and accordingly, the piezoelectric oscillator  32  is elongated in the longitudinal direction as shown by the void portions of FIG. 4 a  and the end face is elongated in the direction shown by the arrow mark X. 
     Further, when the output potential of the alternating current power source  6  becomes lower than the reference potential, the end face of the piezoelectric oscillator  31  is inclined in the direction of the arrow mark Y′ reverse to the arrow mark Y, further, the end face of the piezoelectric oscillator  32  is contracted in the direction 180 degree reverse to the arrow mark X. 
     That is, the bending vibration produced in the piezoelectric oscillator  31  and the elongation and contraction vibration produced in the piezoelectric oscillator  32  are synthesized, as a result, the end face of the piezoelectric element  30  carries out the elliptic motion in the direction shown by the arrow mark Z of FIG. 4 d,  accordingly, the ultrasonic motor  3  moves a moving body (illustration is omitted) which is brought into press contact with the end face in the direction designated by the arrow mark Z. 
     Next, when the phase of the signal from the alternating current power source  6  is inverted by 180 degree by the phase inverter circuit  19 , there is brought about a drive state similar to that in FIG. 5 b.    
     When the output potential of the alternating current power source  6  becomes higher than the reference potential, the polarized region  31   a  and the polarized region  31   d  of the piezoelectric oscillator  31  are contracted in the longitudinal direction and the polarized region  31   b  and the polarized region  31   c  are elongated in the longitudinal direction. Accordingly, the piezoelectric oscillator  31  is bent as shown by the void portions of FIG. 5 c  and the end face is inclined in the direction designated by the arrow mark Y′. 
     At this occasion, as mentioned above, substantially an entire face of the piezoelectric oscillator  32  is polarized in the direction the same as that of the polarized region  31   a  and therefore, the piezoelectric oscillator  32  is elongated in the longitudinal direction as shown by the void portions of FIG. 5 a  and the end face is elongated in the direction designated by the arrow mark X. 
     Further, when the output potential of the alternating current power source  6  becomes lower than the reference potential, the end face of the piezoelectric oscillator  31  is inclined in the direction of the arrow mark Y reverse to the arrow mark Y′, further, the end face of the piezoelectric oscillator  32  is contracted in the direction 180 degree reverse to the arrow mark X. 
     Therefore, the end face of the piezoelectric element  30  carries out the elliptic motion in the direction shown by the arrow mark Z, of FIG. 5 d,  accordingly, the ultrasonic motor  3  moves the moving body (illustration is omitted) which is brought into press contact with the end face in the direction designated by the arrow mark Z′, that is, the direction reverse to the arrow mark Z of FIG. 4 d.    
     That is, the electrodes  36   a ,  36   b ,  36   c  and  36   d  of the piezoelectric oscillator  31  of the ultrasonic motor  3  are connected to the alternating current power source  6  via the phase inverter circuit  19  and accordingly, the direction in which the ultrasonic motor  3  moves the moving body  34   a  can be reversed simply by selecting whether the phase of the signal from the alternating current power source  6  is inverted. 
     In this way, according to the ultrasonic motor  3  of the third embodiment of the invention, the piezoelectric oscillators  32  as the elongation and contraction vibration source are integrally laminated on the piezoelectric oscillators  31  as the bending vibration source and accordingly, the elongation and contraction vibration and the bending vibration can separately be controlled by, for example, separately setting and changing the input signal to the piezoelectric oscillators  31  and the input signal to the piezoelectric oscillators  32 . 
     Further, the bending vibration is carried out by inputting the drive signal from the alternating current power source  6  to all of the polarized regions  31   a,    31   b,    31   c  and  31   d  of the piezoelectric oscillator  31  and accordingly, only the bending vibration is excited and further, a drive force thereof is large and output of the ultrasonic motor  3  is larger than that of the conventional ultrasonic motor. 
     Further, respective pluralities of the piezoelectric oscillators  31  and the piezoelectric oscillators  32  are used and accordingly, the output is further magnified. 
     Further, the ultrasonic motor  3  is driven by a single one of an input signal and accordingly, the constitution of the self-excited oscillation circuit is simplified and therefore, self-excited oscillation control is facilitated. 
     Further, the ultrasonic motor  3  can switch the moving direction of the moving body  14   a  simply by selecting whether a phase of a signal is inverted by the phase inverter circuit  19 . 
     The piezoelectric oscillators  31  and  32  can naturally be driven even when the piezoelectric oscillators  31  and  32  are applied with signals having different phases, for example, signals of 90 degree or −90 degree. 
     Further, although according to the piezoelectric element  30  of the embodiment, four sheets of the piezoelectric oscillators  31  are integrally laminated, on top thereof, four sheets of the piezoelectric oscillators  32  are integrally laminated, the invention is not limited thereto but the piezoelectric element  30  may be constructed by a structure in which the piezoelectric oscillators  31  and the piezoelectric oscillators  32  are laminated alternately integrally. Further, numbers of sheets of the piezoelectric oscillators  31  and  32  may naturally be set arbitrarily and both need not to be the same. Particularly, by making the both different from each other, two of vibrational forces can independently be controlled and accordingly, a ratio of numbers of sheets is set in accordance with required specification of a motor. 
     Further, the electrodes  36   a ,  36   b ,  36   c  and  36   d  need not to be separate and even when the electrodes are shortcircuited into one electrode, the ultrasonic motor  3  is operated with no problem. 
     Further, although the electrodes  36   a ,  36   b ,  36   c  and  36   d  of the piezoelectric oscillator  31  are connected to the alternating current power source  6  via the phase inverter circuit  19 , the invention is not limited thereto but contrary to the embodiment, the electrodes  36   a ,  36   b ,  36   c  and  36   d  of the piezoelectric oscillator  31  may directly be connected to one side of the alternating current power source  6  without interposing the phase inverter circuit  19 , further, the electrode  36   f  of the piezoelectric oscillator  32  may be connected to the alternating current power source  6  via the phase inverter circuit  19 . 
     Although a drive circuit of the embodiment becomes more complicated than those of the first embodiment and the second embodiment by an amount of adding the phase inverter circuit  19 , the piezoelectric oscillators  31  and  32  contributing to drive operation can be installed at a space the same as that of the piezoelectric oscillator  18  constituting the insulating member and therefore, further downsizing and high output formation can be achieved. 
     Further, in comparison with the case in which a signal the phase of which is shifted by 90 degree or −90 degree is produced as shown by the conventional example, the signal is simply inverted and accordingly, the circuit constitution is simplified and the self-excited oscillation circuit is also easy to constitute. 
     Fourth Embodiment 
     FIG. 12 is a block diagram of an electronic apparatus  6  having an ultrasonic motor in which the ultrasonic motor according to the invention is applied to the electronic apparatus. 
     The electronic apparatus  6  having a ultrasonic motor is realized by providing a piezoelectric element  31  subjected to predetermined polarizing treatment, an oscillator  32  coupled to the piezoelectric element  31 , a moving member  33  moved by the oscillator  32 , a pressing mechanism  34  for pressing the oscillator  32  and the moving body  33 , a transmission mechanism  35  moved in cooperation with the moving body  33  and an output mechanism  36  moved based on the operation of the transmission mechanism  35 . 
     In this case, as the piezoelectric oscillator  31 , the piezoelectric element  10  or the piezoelectric element  20  is used. Further, the switches  17   a  and  17   b  or the switches  27   a  and  27   b  are installed pertinently between the piezoelectric element and an alternating current power source (illustration is omitted). 
     Further, as the transmission mechanism  35 , for example, a transmission wheel of a gear, a friction wheel or the like is used. As the output mechanism  36 , for example, there is used a shutter drive mechanism or a lens drive mechanism in a camera, an indicating hand drive mechanism or a calendar drive mechanism in an electronic timepiece, when used in a storage apparatus, a head drive mechanism for driving a head reading and writing information to and from a storage medium in the information storage apparatus, a tool feed mechanism or a working member feed mechanism in a machine tool or the like. 
     Further, as the electronic apparatus  6  having a ultrasonic motor, for example, there is pointed out an electronic timepiece, a measuring instrument, a camera, a printer, a printing machine, a machine tool, a robot, a moving apparatus, a storage apparatus or the like. 
     The electronic apparatus  6  having a ultrasonic motor uses a ultrasonic motor which is smaller than the conventional ultrasonic motor and is provided with larger output than the conventional ultrasonic motor and in which self-excited oscillation drive having simple circuit constitution is used in driving operation and accordingly, the size of the ultrasonic motor and its peripheral circuit are downsized and therefore, the electronic apparatus  6  having the ultrasonic motor is more downsized than the conventional electronic apparatus. 
     Further, by constituting to laminate a plurality of piezoelectric oscillators each having a thin thickness, the electronic apparatus  6  having the ultrasonic motor can be driven by low voltage and can directly be driven by a battery power source. 
     Further, by constructing a constitution in which an output shaft is attached to the moving body  3  and a power transmission mechanism for transmitting torque from the output shaft is installed, the drive mechanism is constituted by a single member of a ultrasonic motor. 
     According to the invention, in respect of the first piezoelectric oscillators, the first polarized regions polarized in the same polarities and the second polarized regions polarized in polarities reverse to those of the first polarized regions, are arranged alternately substantially over entire face thereof and drive signals having the same phase are inputted to the plurality of polarized regions and accordingly, large bending vibration is produced. Further, in the second piezoelectric oscillators as the elongation and contraction vibration source installed separately from the first piezoelectric oscillators, large elongation and contraction vibration is produced. Further, the first piezoelectric oscillators and the second piezoelectric oscillators are integrally formed and accordingly, the bending vibration and the elongation and contraction vibration are synthesized without leakage. Accordingly, an ultrasonic motor having large output can be fabricated. 
     Further, in the case of a ultrasonic motor having an output the same as that of a conventional ultrasonic motor, the ultrasonic motor is downsized. 
     Further, by separately controlling the first piezoelectric oscillators and the second piezoelectric oscillators, elongation and contraction vibration and bending vibration can separately be controlled. 
     Further, the ultrasonic motor is driven by a single one of an input signal and accordingly, the self-excited oscillation circuit is simplified, therefore, self-excited oscillation control is facilitated. 
     Further, according to the invention, other than achieving an effect similar to that in the above-described aspect of the invention, respective pluralities of the first piezoelectric oscillators and the second piezoelectric oscillators are used and accordingly, the output is further magnified. 
     Further, according to the invention, the same signal source is used as the signal source having the same phase and accordingly, a peripheral circuit of the ultrasonic motor is simplified. 
     Further, according to the invention, either of the first piezoelectric oscillators and the second piezoelectric oscillators is connected to the signal source via switching means for inverting a phase of a signal and accordingly, by only switching the switching means, an input signal to either of the first piezoelectric oscillators and the second piezoelectric oscillators is inverted and accordingly, the drive direction of the ultrasonic motor is reversed. 
     Further, according to the invention, the drive direction of the ultrasonic motor can directly be controlled by using switching elements and accordingly, the constitution of the drive circuit is simplified. 
     Further, according to the invention, the above-described ultrasonic motor having an output larger than that of the conventional ultrasonic motor is used and accordingly, the size of the ultrasonic motor and its peripheral circuit are downsized, therefore, the electronic apparatus having the ultrasonic motor is downsized. 
     Further, when self-excited oscillation control is used as the control method of the ultrasonic motor, a positioning accuracy of a movable portion of the electronic apparatus having the ultrasonic motor is promoted, further, downsizing of the electronic apparatus can be realized.