Patent Publication Number: US-2010122386-A1

Title: Driving apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a driving apparatus for driving a probe or the like in a uniaxial direction or biaxial directions so that the probe scans the surface or the like of a medium. 
     BACKGROUND ART 
     For example, the development of a probe memory has been advanced which records data onto a recording medium or which reproduces the data recorded on the recording medium by displacing a probe array including a plurality of probes along a recording surface of the recording medium. In such a probe memory, the location of the probe array with respect to the recording medium (in other words, a position relation between the probe array and the recording medium) is determined, for example, by displacing a stage provided with the probe array. In other words, the location of the probe array with respect to the recording medium is determined by the operations of a MEMS (Micro Electro Mechanical System) actuator which is provided with the stage and which can displace the stage. 
     As a specific structure for displacing the stage provided with the probe array, for example, a MEMS actuator disclosed in a non-patent document 1 is listed as one example. In such a MEMS actuator, the stage is displaced by applying a force to the stage such that the stage oscillates at a relatively low frequency (more specifically, at a frequency lower than the minimum resonance frequency of a spring-mass system including the stage). As described above, the reason why a force is applied to the stage to oscillate the stage at a frequency lower than the minimum resonance frequency is because it is considered that if the force is applied to the stage to oscillate the stage at a frequency near a resonance frequency, the gain of the oscillation (i.e. oscillation range) becomes too large, or it becomes harder to control a position at a frequency higher than the resonance frequency, resulting in unstable operations of the stage (i.e. operations of the MEMS actuator). By this, it is possible to stabilize the operations of the MEMS actuator. 
     Non-Patent document 1: Tatehiko Hasebe, Seiko Yamanaka, Takeshi Harada, Yasushi Mutou, “Development of wide lateral stroke electro-magnetic actuator driven by low voltage”, IEEJ Sensors and Micromachines Society Sogo-Kenkyukai/Micromachines and Sensor systems Kenkyu-kai, No. MSS-06-12 
     DISCLOSURE OF INVENTION 
     Subject to be Solved by the Invention 
     On the other hand, for the MEMS actuator, due to its small size, lower power consumption is desired. Moreover, in order to increase a recording capacity of the recording medium, it is aimed to increase its recording density to be extremely high and to reduce a recording pitch to be on the order of nanometers. When the data is recorded into such an ultramicro area by using the probes, performances are influenced by slight distortion in the driving position of the stage and position repeatability. Thus, it is desired to displace the stage more efficiently. 
     The above can be listed as one example of the subject to be solved by the invention. It is therefore an object of the present invention to provide, for example, a driving apparatus (i.e. MEMS actuator) which can realize the lower power consumption and which can realize the stabilization of a drive position by displacing a stage more efficiently. 
     The above object of the present invention can be achieved by a driving apparatus provided with: a base portion; a stage portion on which a driven object is mounted and which can be displaced; an elastic portion which connects the base portion and the stage portion and which has elasticity to displace the stage portion in one direction; and a first applying device for intermittently applying an excitation force for displacing the stage portion such that the stage portion is resonated in the one direction at a resonance frequency determined by the stage portion and the elastic portion, the excitation force being caused by a piezoelectric effect. 
     These operation and other advantages of the present invention will become more apparent from the embodiment explained below. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram conceptually showing the structure of a ferroelectric recording/reproducing apparatus in example. 
         FIG. 2  are a plan view and a cross sectional view conceptually showing one example of a recording medium used in the example. 
         FIG. 3  is a cross sectional view conceptually showing a data recording operation. 
         FIG. 4  is a cross sectional view conceptually showing a data reproduction operation. 
         FIG. 5  is a plan view conceptually showing the structure of a driving apparatus in a first example. 
         FIG. 6  is a plan view conceptually showing an aspect when a stage of the driving apparatus in the first example shown in  FIG. 5  is displaced. 
         FIG. 7  is a plan view conceptually showing the structure of a driving apparatus in which the stage is displaced by applying an excitation force caused by an electromagnetic force to a base. 
         FIG. 8  is a plan view conceptually showing the structure of a driving apparatus in which the stage is displaced by applying an excitation force caused by an electrostatic force to the base. 
         FIG. 9  is a plan view conceptually showing the structure of a driving apparatus in a second example. 
         FIG. 10  is a plan view conceptually showing the structure of a driving apparatus in which the stage is displaced by applying the excitation force caused by the electromagnetic force to two suspensions. 
         FIG. 11  is a plan view conceptually showing the structure of a driving apparatus in which the stage is displaced by applying the excitation force caused by the electrostatic force to the two suspensions. 
         FIG. 12  is a plan view conceptually showing the structure of a driving apparatus in a third example. 
         FIG. 13  is a plan view conceptually showing the structure of a driving apparatus in which the stage is displaced by applying the excitation force caused by the electromagnetic force to the stage. 
         FIG. 14  is a plan view conceptually showing the structure of a driving apparatus in which the stage is displaced by applying the excitation force caused by the electrostatic force to the stage. 
         FIG. 15  is a plan view conceptually showing the structure of a driving apparatus in a fourth example. 
         FIG. 16  is a plan view conceptually showing an aspect when the driving apparatus in the fourth example operates. 
         FIG. 17  is a plan view conceptually showing the structure of a driving apparatus in which the mass of the stage is adjusted. 
         FIG. 18  is a plan view conceptually showing a driving apparatus in a fifth example. 
         FIG. 19  is a plan view conceptually showing one aspect when a first stage of the driving apparatus in the fifth example shown in  FIG. 18  is displaced. 
         FIG. 20  is a plan view conceptually showing another aspect when the first stage of the driving apparatus in the fifth example shown in  FIG. 18  is displaced. 
         FIG. 21  is a plan view conceptually showing the structure of a driving apparatus in which a second stage is displaced in a Y-axis direction by applying the excitation force caused by the electromagnetic force to the first stage. 
         FIG. 22  is a plan view conceptually showing the structure of a driving apparatus in which the second stage is displaced in the Y-axis direction by applying the excitation force caused by the electrostatic force to the first stage. 
         FIG. 23  is a plan view conceptually showing the structure of a driving apparatus provided with two types of driving sources for displacing the second stage in the Y-axis direction. 
         FIG. 24  is a plan view conceptually showing the structure of a driving apparatus provided with a plurality of second stages on the first stage. 
         FIG. 25  is a plan view conceptually showing the structure of a driving apparatus in a sixth example. 
         FIG. 26  is a plan view conceptually showing another structure of the driving apparatus in the sixth example. 
         FIG. 27  is a plan view conceptually showing the structure of a driving apparatus provided with the plurality of second stages on the first stage. 
         FIG. 28  is a plan view conceptually showing the structure of a driving apparatus in a seventh example. 
         FIG. 29  is a plan view conceptually showing an aspect when the stage of the driving apparatus in the seven example shown in  FIG. 28  is displaced. 
         FIG. 30  is a plan view conceptually showing trajectories of the displacement of a plurality of probes realized by a driving apparatus in an eighth example. 
     
    
    
     DESCRIPTION OF REFERENCE CODES 
     
         
           1  ferroelectric recording/reproducing apparatus 
           12  probe 
           30  recording medium 
           100  driving apparatus 
           110  base 
           120  suspension 
           130  stage 
           141 ,  143  electrode 
           142  piezoelectric element 
           144  force transmission mechanism 
           151  coil 
           152  magnetic pole 
           161 ,  162  electrode 
           170  spring constant adjustment device 
           171  member 
           172  spring 
           173  stage mass adjustment device 
           180  driving source 
       
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, as the best mode for carrying out the present invention, an explanation will be given on embodiments of the driving apparatus of the present invention. 
     An embodiment of the driving apparatus of the present invention is by a driving apparatus provided with: a base portion; a stage portion on which a driven object is mounted and which can be displaced; an elastic portion which connects the base portion and the stage portion and which has elasticity to displace the stage portion in one direction; and a first applying device for intermittently applying an excitation force for displacing the stage portion such that the stage portion is resonated in the one direction at a resonance frequency determined by the stage portion and the elastic portion, the excitation force being caused by a piezoelectric effect. 
     According to the embodiment of the driving apparatus of the present invention, by the operation of the first applying device, the excitation force is applied that allows the stage portion connected to the base portion (i.e. the fixed base portion which is the foundation) through the elastic portion including various springs to be resonated in the one direction (e.g. Y-axis direction) at the resonance frequency determined by the stage portion and the elastic portion. In other words, due to the excitation force applied by the first applying device, the stage portion is displaced (in other words, movable) to be resonated at the resonation frequency. 
     In the embodiment, in particular, the excitation force applied by the first applying device is a force caused by a piezoelectric effect. More specifically, the first applying device is provided with, for example, a piezoelectric element and two electrodes disposed to hold the piezoelectric element therebetween. To at least one of the two electrodes, a desired voltage is applied. The application of the voltage to the electrode changes the shape of the piezoelectric element. In the embodiment, the change of the shape of the piezoelectric element is applied as the excitation force. 
     As described above, in the embodiment, when the stage portion is displaced, the characteristic of resonance is used. Here, the “resonance” is a phenomenon in which repetition or superposition of infinitesimal forces causes infinite displacement. Thus, even if the excitation force is reduced which is necessary to displace the stage portion, it is possible to increase the displacement range of the stage portion. In other words, it is possible to relatively reduce the excitation force necessary for the displacement of the stage. Thus, it is also possible to reduce electric energy which is necessary to apply the excitation force necessary for the displacement of the stage portion. Therefore, it is possible to displace the stage portion more efficiently, resulting in lower power consumption. 
     Incidentally, in the construction described in the aforementioned Background Art, the stage portion is displaced such that the stage portion oscillates at a lower frequency than the minimum resonance frequency. In the present invention, however, for the purpose of lower power consumption, the stage portion is displaced such that the stage portion oscillates at the resonance frequency. Such lower power consumption can be said to be particularly effective in a small apparatus such as a MEMS actuator. 
     In addition, in the driving apparatus in which the stage portion is displaced by applying a force having directionality, the position (balance) of the stage portion is possibly distorted depending on a direction and a location on which the force applied to the stage portion acts. In other words, if the force is not applied to the center of gravity of the stage portion, the position of the stage portion is possibly distorted. Alternatively, if the force applied to the stage portion includes a rotational component, the position of the stage portion is possibly distorted. This may result in a loss of repeatability with respect to aspects of the displacement of the stage portion. In the embodiment, however, the free or independent behavior of the oscillation system itself including the stage portion and the elastic portion, which is the resonance, is used to displace the stage portion, so that it is possible to preferably maintain the stability of the position of the stage portion. As a result, it is possible to preferably obtain the repeatability with respect to aspects of the displacement of the stage portion. 
     Then, if a probe array as the driven object is disposed on the stage portion and if the recording medium is disposed to face the probe array, each of the plurality of probes included in the probe array can be displaced at a desired position on the recording medium. As a result, it is possible to record data at the desired position on the recording medium or to reproduce the data recorded at the desired position on the recording medium. 
     Moreover, in the embodiment, the excitation force caused by the piezoelectric effect is applied. Thus, although the amount of change of the shape of the piezoelectric element is relatively small, it is possible to apply the excitation force which is relatively large. In other words, it is possible to apply the large excitation force, with hardly increasing the amount of change of the shape of the piezoelectric element. 
     Moreover, in the embodiment, the excitation force is intermittently applied. For example, if the resonance frequency is f0 as described later, the excitation force is applied once in every period of 1/f0 or in every period that is M times the period of 1/f0 (wherein M is an integer of 2 or more). Even in such construction, since the excitation force caused by the piezoelectric effect is relatively large, the stage portion can be preferably resonated. On the other hand, it is no longer necessary to apply the excitation force all the time. Thus, it is possible to further reduce the electric energy which is necessary to apply the excitation force. 
     In one aspect of the embodiment of the driving apparatus of the present invention, the first applying device applies the excitation force to the base portion. 
     According to this aspect, by applying the excitation force to the base portion, it is possible to displace the stage portion to be resonated at the resonance frequency. 
     In another aspect of the embodiment of the driving apparatus of the present invention, it is further provided with a second applying device for applying a driving force for displacing, in a stepwise manner or in a continuous manner, the stage portion or the driven object mounted on the stage portion in other direction which is substantially perpendicular to the one direction. 
     According to this aspect, by the operation of the second applying device, the driving force is applied to displace the stage portion itself or the driven object mounted on the stage portion in the other direction (e.g. X-axis direction), in the stepwise manner or in the continuous manner. By this, the stage portion or the driven object mounted on the stage portion is displaced to perform a tracking operation in the other direction. Here, as the structure for displacing the stage portion in the other direction, two structures are listed as one example: (i) a structure for displacing the entire resonance/oscillation system including the base portion, the stage portion, and the elastic portion, and (ii) a structure for further displacing only the driven object (e.g. another stage portion) mounted on the stage portion that is displaced to be resonated. 
     Thus, the stage portion can be displaced in the other direction, and the stage portion or the driven object mounted on the stage portion can be resonated in the other direction. By this, it is possible to resonate the stage portion or the driven object mounted on the stage portion in the one direction and to displace it in the other direction; namely, it is possible to biaxially drive the stage portion. Therefore, it is possible to record the data onto the substantially entire recording surface on the recording medium, or to reproduce the data recorded on the substantially entire recording surface on the recording medium. 
     In another aspect of the embodiment of the driving apparatus of the present invention, the first applying device applies the excitation force with a period according to the resonance frequency. 
     According to this aspect, for example, if the resonance frequency is f0, the excitation force is applied with a period of 1/f0 or with a period that is N times or 1/N times the period of 1/f0 (wherein N is an integer of 1 or more). In other words, the excitation force is applied once in every period of 1/f or in every period that is N times or 1/N times the period of 1/f0 (wherein N is an integer of 1 or more). As a result, the excitation force is applied in timing to increase or maintain the resonance in accordance with aspects of the resonance of the stage portion. By this, the stage portion is displaced to be resonated at the resonance frequency. Therefore, it is possible to preferably receive the aforementioned various effects. 
     These operation and other advantages of the present invention will become more apparent from the examples explained below. 
     As explained above, according to the embodiment of the driving apparatus of the present invention, it is provided with the base portion, the stage portion, the elastic portion, and the first applying device. Therefore, by displacing the stage more efficiently and stably, it is possible to realize lower power consumption and position stabilization. 
     EXAMPLES 
     Hereinafter, examples of the driving apparatus of the present invention will be described with reference to the drawings. 
     (1) Information Recording/Reproducing Apparatus 
     Firstly, with reference to  FIG. 1  to  FIG. 4 , an explanation will be given on an information recording/reproducing apparatus provided with any of the examples of the driving apparatus of the present invention. Incidentally, here, an explanation will be given on a ferroelectric recording/reproducing apparatus which performs a recording operation or reproduction operation on a recording medium  30  in which a ferroelectric substance is used as a recording material. 
     (1-1) Structure 
     Firstly, the structure of a ferroelectric recording/reproducing apparatus in the example will be explained with reference to  FIG. 1 .  FIG. 1  is a block diagram conceptually showing the structure of a ferroelectric recording/reproducing apparatus in example. 
     As shown in  FIG. 1 , a ferroelectric recording/reproducing apparatus  1  is provided with a probe  12  which is close to or in contact with a recording medium  30  and which is provided for a driving apparatus (in other words, a MEMS actuator)  100 ; and the recording medium  30  which is disposed at a position facing to the probe  12 . Moreover, the ferroelectric recording/reproducing apparatus  1  is provided with a return electrode  11  for returning thereto a high-frequency signal for signal reproduction, applied from the probe  12 ; an inductor L which is disposed between the probe  12  and the return electrode  11 ; an oscillator  13  which oscillates at a resonance frequency determined by the inductor L and a capacitance Cs in a site that is polarized in accordance with record information and that is formed in an outer layer of or within a dielectric material  31  under the probe  12 ; an alternating current (AC) signal generator  16  for applying an alternating electric field which is to detect the state of polarization recorded in the dielectric material  31 ; a record signal generator  17  for recording the polarization state into the dielectric material  31 ; a switch  18  for changing the outputs of the AC signal generator  16  and the record signal generator  17 ; a HPF (High Pass Filter)  15 ; a demodulator  19  for demodulating a FM signal modulated by the capacitance corresponding to the polarization state owned by the dielectric material  31  under the probe  12 ; a signal detector  20  for detecting data from a demodulated signal; a tracking error detector  21  for detecting a tracking error signal from the demodulated signal; an actuator drive circuit  22  for controlling the operations of the driving apparatus  100 ; and the like. 
     The probe  12  is connected to the oscillator  13  through the HPF  15 , and it is connected to the AC signal generator  16  and the record signal generator  17  through the HPF  15  and the switch  18 . Moreover, the probe  12  functions as an electrode for applying an electric field to the dielectric material  31 . 
     Incidentally, the probe  12  is disposed on a stage  130  provided for the driving apparatus  100  described later, and the probe  12  can be planarly displaced along a recording surface of the recording medium  30 . The displacement operation of the probe  12  is performed under the control of the actuator drive circuit  22 . Incidentally, the displacement operation of the probe  12  (in other words, the structure and operations of the driving apparatus  100 ) will be detailed later. 
     The return electrode  11  is an electrode for returning thereto a high-frequency electric field applied to the dielectric material  31  from the probe  12  (i.e. a resonance electric field from the oscillator  13 ), and the return electrode  11  is disposed to surround the probe  12 . Incidentally, the shape and placement of the return electrode  11  can be arbitrarily set as long as the high-frequency electric field returns to the return electrode  11  without resistance. 
     Incidentally, in the examples, only one probe  12  is shown in  FIG. 1  for simplification of explanation; however, a plurality of probes  12  are preferably provided in order to improve a recording speed and a reproduction speed. In this case, a plurality of AC signal generators  16  are provided in association with the respective probes  12 . Moreover, a plurality of signal detectors  20  are provided in order to discriminate between reproduction signals corresponding to the AC signal generators  16  on the signal detectors  20 , and the signal detectors  20  obtain reference signals from the respective AC signal generators  16 , thereby outputting the corresponding reproduction signals. 
     The inductor L is disposed between the probe  12  and the return electrode  11 , and it is formed from, for example, a microstripline. A resonance circuit  14  is constructed including the inductor L and the capacitance Cs. The inductance of the inductor L is determined such that this resonance frequency is, for example, approximately 1 GHz. 
     The AC signal generator  16  applies an alternating electric field to a micro domain between the return electrode  11  and an electrode  32 . Moreover, the ferroelectric recording/reproducing apparatus which uses a plurality of probes  12  performs synchronization by using the frequencies of the alternating electric fields as reference signals, thereby discriminating signals detected on the probes  12 . The frequencies are centered on about 100 kHz. 
     The oscillator  13  is an oscillator which oscillates at the resonance frequency determined from the inductor L and the capacitance Cs. The oscillation frequency varies depending on the change of the capacitance Cs. Therefore, FM modulation is performed in association with the change, which is due to the alternating field, of the capacitance Cs determined by the polarization state corresponding to the recorded data. By demodulating this FM modulation, it is possible to read the data recorded on the recording medium  30 . 
     Incidentally, as described in detail later, the probe  12 , the return electrode  11 , the oscillator  13 , the inductor L, the HPF  15 , and the capacitance Cs in the dielectric material  31  constitute the resonance circuit  14 , and the FM signal amplified in the oscillator  13  is outputted to the demodulator  19 . 
     The record signal generator  17  generates a signal for recording and supplies it to the probe  12  at the time of recording. This signal is not limited to a digital signal and it may be an analog signal. The signal includes various signals, such as audio information, video information, and digital data for a computer. Moreover, the AC signal superimposed on the record signal is used to discriminate and reproduce the information on each probe, as the reference signal at the time of signal reproduction. 
     The switch  18  selects the output such that the signal from the AC signal generator  16  is supplied to the probe  12  at the time of reproduction and the signal from the record signal generator  17  is supplied to the probe  12  at the time of recording. For this apparatus, a mechanical relay and a semiconductor circuit are used. The switch  18  is preferably constructed from the relay in the case of the analog signal, and the semiconductor circuit in the case of the digital signal. 
     The HPF  15  includes an inductor and a condenser, and it is used to form a high pass filter for cutting off a signal system so that the signals from the AC signal generator  16  and the record signal generator  17  do not interfere with the oscillation of the oscillator  13 . The cutoff frequency is f=½π√ {LC}. Here, L is the inductance of the inductor included in the HPF  15 , and C is the capacitance of the condenser included in the HPF  15 . The frequency of the AC signal outputted from the AC signal generator  16  is about 100 KHz, and the oscillation frequency of the oscillator  13  is about 1 GHz. Thus, the separation is sufficiently performed on a first order LC filter. A higher-order filter may be used, but that increases the number of elements and possibly increases the apparatus size. 
     The demodulator  19  demodulates the FM signal and reconstructs a waveform corresponding to the polarization state of a site which is traced by the probe  12 . If the recorded data are digital data of “0” and “1”, there are two types of frequencies to be modulated. By judging the frequency, the data reproduction is easily performed. 
     The signal detector  20  reproduces the recorded data from the signal demodulated on the demodulator  19 . As the signal detector  19 , for example, a lock-in amplifier is used, and coherent detection or synchronized detection is performed on the basis of the frequency of the alternating electric field of the AC signal generator  16 , to thereby reproduce the data. Incidentally, it is obvious that another phase detection device may be used. 
     The tracking error detector  21  detects a tracking error signal for controlling the apparatus, from the signal demodulated on the demodulator  19 . The detected tracking error signal is inputted into a tracking mechanism, for the control. 
     Next, one example of the recording medium  30  using the dielectric material shown in  FIG. 1  will be explained with reference to  FIG. 2 .  FIG. 2  are a plan view and a cross sectional view conceptually showing one example of the recording medium  30  used in the example. 
     As shown in  FIG. 2(   a ), the recording medium  30  has, for example, a rectangular shape. By relatively displacing the aforementioned probe  12  on the recording surface of the recording medium  30 , the data is recorded onto the recording medium  30 , or the data recorded on the recording medium  30  is reproduced. 
     Moreover, as shown in  FIG. 2(   b ), the recording medium  30  is formed such that the electrode  32  is laminated on a substrate  33  and that the dielectric material  31  is laminated on the electrode  32 . 
     The substrate  33  is, for example, Si (silicon) which is a preferable material in its strength, chemical stability, workability, or the like. The electrode  32  is intended to generate an electric field between the probe  12  (or the return electrode  11 ) and the electrode  32 . By applying the electric field that is equal to or stronger than the coercive electric field of the dielectric material  31  to the dielectric material  31 , the polarization direction is determined. By determining the polarization direction in accordance with the data, the recording is performed. 
     The dielectric material  31  is formed by a known technology, such as spattering LiTaO 3  or the like which is a ferroelectric substance, onto the electrode  32 . Then, the recording is performed with respect to the Z surface of LiTaO 3  in which the plus and minus surfaces of the polarization have a 180-degree domain relation. It is obvious that another dielectric material may be used. In the dielectric material  31 , the small polarization is formed at high speed by a voltage for data recording, which is applied simultaneously with a direct current bias voltage. 
     (1-2) Operation Principle 
     Next, with reference to  FIG. 3  and  FIG. 4 , the operation principle of the ferroelectric recording/reproducing apparatus  1  in the example will be explained. Incidentally, in the explanation below, one portion of the constituent elements of the ferroelectric recording/reproducing apparatus  1  shown in  FIG. 1  is extracted and explained. 
     (1-2-1) Recording Operation 
     Firstly, with reference to  FIG. 3 , the recording operation of the ferroelectric recording/reproducing apparatus  1  in the example will be explained.  FIG. 3  is a cross sectional view conceptually showing the data recording operation. 
     As shown in  FIG. 3 , by applying an electric field which exceeds the coercive electric field of the dielectric material  31  between the probe  12  and the electrode  32 , the dielectric material  31  is polarized having a direction corresponding to the direction of the applied electric field. Then, by controlling an applied voltage to thereby change the polarization direction, it is possible to record the predetermined information. This uses such a characteristic that if an electric field which exceeds the coercive electric field of a dielectric substance is applied to the dielectric substance (particularly, a ferroelectric substance), the polarization direction is reversed, and that the polarization direction is maintained thereafter. 
     For example, it is assumed that the micro domain has downward polarization P when an electric field is applied which directs from the probe  12  to the electrode  32 , and that the micro domain has upward polarization P when an electric field is applied which directs from the electrode  32  to the probe  12 . This corresponds to the state that the data information is recorded. If the probe  12  is displaced in an arrow-pointing direction by the operation of the driving apparatus  100 , a detection voltage corresponds to the polarization P and is outputted as a rectangular wave which swings up and down. 
     (1-2-2) Reproduction Operation 
     Next, with reference to  FIG. 4 , the reproduction operation of the ferroelectric recording/reproducing apparatus  1  in the example will be explained.  FIG. 4  is a cross sectional view conceptually showing the data reproduction operation. 
     The nonlinear dielectric constant of a dielectric substance changes in accordance with the polarization direction of the dielectric substance. Moreover, the nonlinear dielectric constant of the dielectric substance can be detected as a difference of the capacitance of the dielectric substance or a difference of the capacitance change when an electric field is applied to the dielectric substance. Therefore, by applying an electric field to the dielectric material and by detecting a difference of the capacitance Cs or a difference of the change of the capacitance Cs in a certain micro domain of the dielectric material at that time, it is possible to read and reproduce the data recorded as the polarization direction of the dielectric material. 
     Specifically, firstly, as shown in  FIG. 4 , an alternating electric field from the not-illustrated AC signal generator  16  is applied between the electrode  32  and the probe  12 . The alternating electric field has an electric field strength which does not exceed the coercive electric field of the dielectric material  31 , and it has a frequency of, for example, approximately 100 kHz. The alternating electric field is generated mainly to discriminate the difference of the capacitance change corresponding to the polarization direction of the dielectric material  31 . Incidentally, instead of the alternating electric field, a direct current bias voltage may be applied to form an electric field in the dielectric material  31 . The application of the alternating electric field causes the generation of an electric field in the dielectric material  31  of the recording medium  30 . 
     Then, the probe  12  is brought closer to the recording surface until the distance between the tip of the probe  12  and the recording surface becomes extremely small on the order of nanometers. In this condition, the oscillator  13  is driven. Incidentally, in order to detect the capacitance Cs of the dielectric material  31  under the probe  12  highly accurately, it is preferable to bring the probe  12  in contact with the surface of the dielectric material  31 , i.e. the recording surface. However, even if the tip of the probe  12  is not brought in contact with the recording surface, for example, if the tip of the probe  12  is brought closer to the recording surface to the extent that it can be substantially regarded as the contact, the reproduction operation (and moreover, the aforementioned recording operation) can be performed. 
     Then, the oscillator  13  oscillates at the resonance frequency of the resonance circuit  14  which includes the capacitance Cs, which is associated with the dielectric material  31  under the probe  12 , and the inductor L as the constituent factors. The center frequency of the resonance frequency is set to approximately 1 GHz, as described above. 
     Here, the return electrode  11  and the probe  12  constitute one portion of the oscillation circuit  14  including the oscillator  13 . The high-frequency signal of approximately 1 GHz, which is applied to the dielectric material  31  from the probe  12 , passes through the dielectric material  31  and returns to the return electrode  11 , as shown by solid lines in  FIG. 4 . By disposing the return electrode  11  in the vicinity of the probe  12  and shortening a feedback route to the oscillation circuit  14  including the oscillator  13 , it is possible to reduce noise (e.g. a floating capacitance component) entering the oscillation circuit  14 . 
     In addition, the change of the capacitance Cs corresponding to the nonlinear dielectric constant of the dielectric material  31  is extremely small, and it is necessary to adopt a detection method having high detection accuracy in order to detect this change. In a detection method using FM modulation, the high detection accuracy can be generally obtained; however, it is necessary to further improve the detection accuracy in order to make it possible to detect the small capacitance change corresponding to the nonlinear dielectric constant of the dielectric material  31 . Thus, in the ferroelectric recording/reproducing apparatus  1  in the example (i.e. a recording/reproducing apparatus which uses the SNDM principle), the return electrode  11  is located in the vicinity of the probe  12  to shorten the feedback route to the oscillation circuit  14  as much as possible. By this, it is possible to obtain extremely high detection accuracy, thereby detecting the small capacitance change corresponding to the nonlinear dielectric constant of the dielectric substance. 
     After the oscillator  13  is driven, the probe  12  is displaced in parallel with the recording surface on the dielectric recording medium  30 . Since the polarization state of the domain of the dielectric material  31  under the probe  12  varies depending on the recorded signal, the nonlinear component of the dielectric constant changes under the probe  12 . If the nonlinear component of the dielectric constant changes, the phase of the resonance frequency, i.e. the oscillation frequency of the oscillator  13 , changes with respect to the alternating electric field. As a result, the oscillator  13  outputs a signal which is FM-modulated on the basis of the polarization state, i.e. the recorded data. 
     This FM signal is frequency-voltage-converted by the demodulator  19 . As a result, the change of the capacitance Cs is converted to the extent of the voltage. The change of the capacitance Cs corresponds to the nonlinear dielectric constant of the dielectric material  31 , and the nonlinear dielectric constant corresponds to the polarization direction of the dielectric material  31 , and the polarization direction corresponds to the data recorded in the dielectric material  31 . Therefore, the signal obtained from the demodulator  19  is such a signal that the voltage changes in accordance with the data recorded on the recording medium  30 . Moreover, the signal obtained from the demodulator  19  is supplied to the signal detector  20  and, for example, coherent detection or synchronized detection is performed to extract the data recorded on the recording medium  30 . 
     At this time, on the signal detector  20 , the AC signal generated by the AC signal generator  16  is used as the reference signal. By this, for example, even if the signal obtained from the demodulator  19  includes many noises or even if the data to be extracted is weak, the data can be extracted highly accurately by performing the synchronization with the reference signal, as described later. 
     (2) Driving Apparatus 
     Next, with reference to  FIG. 5  to  FIG. 30 , an explanation will be given on the driving apparatus  100  for driving the plurality of probes  12  provided for the ferroelectric recording/reproducing apparatus  1  in the examples. 
     (2-1) Driving Apparatus Adopting Uniaxial Driving Method 
     Firstly, with reference to  FIG. 5  to  FIG. 17 , of the driving apparatus  100  in the examples, driving apparatuses adopting a uniaxial driving method (specifically, a driving apparatus in a first example to a driving apparatus in a fourth example described later) will be described. Incidentally, the driving apparatus adopting the uniaxial driving method is a driving apparatus that can displace the probes  12  along one axis (e.g. Y axis). In other words, the driving apparatus adopting the uniaxial driving method is a driving apparatus that can realize the one-dimension displacement of the probes  12 . 
     (2-1-1) First Example of Driving Apparatus 
     Firstly, with reference to  FIG. 5  and  FIG. 6 , a driving apparatus  100   a  in a first example will be explained.  FIG. 5  is a plan view conceptually showing the structure of the driving apparatus  100   a  in the first example.  FIG. 6  is a plan view conceptually showing an aspect when a stage  130  of the driving apparatus  100   a  in the first example shown in  FIG. 5  is displaced. 
     As shown in  FIG. 5 , the driving apparatus  100   a  in the first example is provided with a base  110 , two suspensions  120 , a stage  130 , an electrode  141 , a piezoelectric element  142 , and an electrode  143 . 
     To the base  110  which is fixed (in other words, which is fixed within a system as being the driving apparatus  100   a ), the two suspensions  120  which extend in a longitudinal direction are fixed at their one edges. Each of the two suspensions  120  constitutes one specific example of the “elastic portion” of the present invention, and it is a member having elasticity such as a spring made of, for example, silicon, copper alloys, iron-type alloys, other metal, resins, and the like. The two suspensions  120  are fixed to the stage  130  at the other edges. In other words, the stage  130  is supported (or hung) by the two suspensions  120 . The stage  130  can be displaced in a Y-axis direction due to the elasticity of the two suspensions  120 ; namely, the stage  130  is displaced in the Y-axis direction by the two suspensions  120 , as shown in  FIG. 6 . Moreover, the aforementioned probes  12  (here, the plurality of proves  12 ) are disposed on the stage  130 . Moreover, the electrode  141  is disposed to hold the piezoelectric element  142  between the electrode  141  and the electrode  143  which is fixed to the base  110  and which is grounded. 
     Incidentally, on the base  110 , the aforementioned recording medium  30  is preferably held. In other words, since the plurality of probes  12  are displaced by disposing the plurality of probes  12  on the stage  130 , the recording medium  30  is preferably constructed to be fixed to the base  110  (i.e. not to displace the recording medium  30 ). 
     Moreover, the base  110  may be constructed as a box-type case which is provided with the two suspensions  120  and the stage  130  in its inner space. In this case, various constituents of the ferroelectric recording/reproducing apparatus  1  explained with reference to  FIG. 1  (excluding at least the probes  12 ) may be disposed within and on the base  110  which is the box-type case. In other words, the ferroelectric recording/reproducing apparatus  1  in the example may be constructed as a card-type memory or the like having the base  110  as the case. Furthermore, it may be also constructed such that the base  110  is a movable body supported or hung by the two suspensions  120 . 
     Here, an explanation will be given on the operations of the driving apparatus  100   a  in the first example having the aforementioned structure. A desired voltage is applied to the electrode  141  in desired timing from the actuator drive circuit  22 . Due to the application of the voltage to the electrode  141 , the piezoelectric element  142  changes its shape. Here, since the electrode  143  is fixed to the base  110 , the change of the shape of the piezoelectric element  142  is added as a force to the base  110  through the electrode  143 . In other words, in the first example, a force caused by the change of the shape of the piezoelectric element  142  due to the application of the voltage (i.e. a piezoelectric effect) is applied to the base  110 . 
     Here, since the base  110  is semifixed and the force is applied at the resonance frequency of the movable body (the two suspensions  120  and the stage  130  in the first example) as described later, the base  110  rarely moves or slightly oscillates even if the force is applied by the piezoelectric element  142  to the base  110 . Moreover, even if the base  110  slightly oscillates, its frequency is sufficiently higher than the frequency of the oscillation of the stage  130  (i.e. the resonance frequency described later). In other words, the amplitude of the oscillation of the base  110  is sufficiently smaller than that of the stage  130 . 
     On the other hand, the two suspensions  120  which are fixed to the base  110  at the one edges start to oscillate in accordance with the force applied by the piezoelectric element  142  to the base  110 . As a result, the stage  130  which is fixed to the other edges of the two suspensions  120  oscillates (i.e. is displaced) in the Y-axis direction as shown in  FIG. 6 . 
     Incidentally, in the explanation below, the force applied to the base  110  to displace the stage  130  (particularly, to oscillate the stage  130  at the resonance frequency) will be referred to as an “excitation force”. 
     In the first example, in particular, the actuator drive circuit  22  applies a desired voltage to the electrode  141  in desired timing so as to apply the excitation force for oscillating (i.e. resonating) the stage  130  at the resonance frequency determined by the two suspensions  120  and the stage  130 . For example, if the mass of the stage  130  is m and a spring constant is k when the two suspensions  120  is regarded as one spring, the actuator drive circuit  22  applies the desired voltage to the electrode  141  in the desired timing so as to apply the excitation force for resonating the stage  130  at a frequency of √ (k/m) (or at a frequency 1/N times the frequency of √ (k/m) (wherein N is an integer of 1 or more). In this case, the actuator drive circuit  22  preferably applies the desired voltage to the electrode  141  so as to apply the excitation force to the base  110  in timing synchronized with the resonance frequency. In other words, if the resonance frequency is f0, the actuator drive circuit  22  preferably applies the desired voltage to the electrode  141  such that the excitation force is applied to the base  110  with a period of 1/f0 or with a period that is M times the period of 1/f0 (wherein M is an integer of 1 or more). Moreover, the actuator drive circuit  22  preferably applies the desired voltage to the electrode  141  so as to apply the excitation force that can maintain the displacement of the stage  130  (i.e. the excitation force that can apply a force acting in the same direction as the displacement direction of the stage  130 ). Of course, if it is desired that the displacement of the stage  130  is stopped (or if it is desired that a range of the displacement of the stage  130  is reduced or attenuated), obviously, it is preferable to apply the excitation force that can stop the displacement of the stage  130  (i.e. the excitation force that can apply to the stage  130  a force applying in the opposite direction of the displacement direction of the stage  130  or the excitation force that can apply to the stage  130  a force applying in the same direction as the displacement direction of the stage  130  in timing in which phases are shifted by 180 degrees). 
     As described above, in the first example, the excitation force is applied to the base  110  in timing according to the resonance frequency determined by the two suspensions  120  and the stage  130 . As a result, the driving apparatus  100   a  in the first example can resonate the stage  130  at the resonance frequency determined by the two suspensions  120  and the stage  130 . In other words, the stage  130  performs self-resonance. 
     Here, the “resonance” is a phenomenon in which repetition or superposition of infinitesimal forces causes infinite displacement. Thus, even if the excitation force is reduced which is applied to the base  110  to displace the stage  130 , it is possible to increase the displacement range of the stage  130 . In other words, it is possible to relatively reduce the excitation force necessary for the displacement of the stage  130 . Thus, it is also possible to reduce electric energy which is necessary to apply the excitation force necessary for the displacement of the stage  130  to the base  110 . Therefore, it is possible to displace the stage  130  more efficiently, resulting in the lower power consumption of the driving apparatus  100   a.    
     In addition, in the driving apparatus in which the stage  130  is displaced by applying to the stage  130  a force having directionality, the position (balance) of the stage  130  is possibly distorted depending on a direction and a location on which the force applied to the stage  130  (specifically, the force applied to the stage  130  in accordance with the excitation force) acts. For example, if the force is not applied to the center of gravity of the stage  130 , the position of the stage  130  is possibly distorted. Alternatively, if the force applied to the stage  130  includes a rotational component, the position of the stage  130  is possibly distorted. This may result in a loss of repeatability with respect to aspects of the displacement of the stage  130 . However, the driving apparatus  100   a  in the first example adopts such a method that the behavior of the oscillation system including the stage  130  and the two suspensions  120 , which is the resonance, is used to displace the stage  130  and to apply the excitation force to the base  110 , so that it is possible to preferably maintain the stability of the position of the stage  130 . As a result, it is possible to preferably obtain the repeatability with respect to aspects of the displacement of the stage  130 . 
     Moreover, as opposed to using a phenomenon in which the oscillation has a high gain when the stage is oscillated at the resonance frequency, in the first example, it is possible to reduce the magnitude of the excitation force at each time by using the phenomenon in which the resonance is the superposition of infinitesimal forces. Thus, it is possible to control the position of the stage  130  to be more stable. 
     Moreover, if the plurality of probes  12  are provided for the stage  130  and if the recording medium  30  is disposed to face the plurality of probes  12 , each of the plurality of probes  12  can be displaced to a desired position on the recording medium  30 . As a result, it is possible to record the data at the desired position on the recording medium  30  or to reproduce the data recorded at the desired position on the recording medium  30 . 
     In addition, in the first example, the excitation force is applied to the base  110 . In other words, a driving source for applying the excitation force (i.e. the electrode  141 , the piezoelectric element  142 , and the electrode  143 ) is fixed to the base  110 . Therefore, it is unnecessary to provide a driving source fixed to the movable portion including the two suspensions  120  and the stage  130 . This can relatively limit or control the generation of a heat caused by the driving source in the movable portion including the two suspensions  120  and the stage  130 . As a result, it is possible to preferably limit or control an adverse effect of the heat on the movable portion including the two suspensions  120  and the stage  130 . 
     Moreover, since the excitation force is applied to the base  110 , it is unnecessary to provide the driving source for the movable portion including the two suspensions  120  and the stage  130 . Thus, it is possible to apply the excitation force without increasing the mass of the movable portion including the two suspensions  120  and the stage  130 . Therefore, it is possible to increase sensitivity related to the displacement of the stage  130 . 
     Moreover, in the first example, the excitation force caused by the piezoelectric effect is applied. Thus, it is possible to apply the relatively large excitation force while the amount of change of the shape of the piezoelectric element  142  (i.e. the amount of displacement of the piezoelectric element  142 ) is relatively small. In other words, it is possible to apply the large excitation force without excessively increasing the amount of change of the shape of the piezoelectric element  142  (i.e. the amount of displacement of the piezoelectric element  142 ). 
     Incidentally, if the excitation force caused by the piezoelectric effect is applied, the excitation force may be applied intermittently. For example, as described above, if the resonance frequency is f0, the excitation force may be applied once in every period of 1/f or in every period that is M times the period of 1/f0 (wherein M is an integer of 2 or more). Even in such construction, it is possible to preferably resonate the stage  130  since the excitation force caused by the piezoelectric effect is relatively large. On the other hand, the excitation force is not necessarily applied all the time, so that it is possible to further reduce the electric energy necessary for the application of the excitation force. However, it is obvious that the excitation force may be applied with a period other than the aforementioned examples or all the time as long as the stage  130  can be resonated. Moreover, even if an excitation force caused by an electromagnetic force or an electrostatic force is applied, the excitation force may be applied intermittently, or the excitation force may be applied all the time. Even in such construction, it is possible to properly receive the same effects as in the case where the excitation force caused by the piezoelectric effect is applied intermittently. This holds true in a second example and the like explained below. 
     Incidentally, in the first example, since the stage  130  is resonated, the displacement velocity of the stage  130  varies sinusoidally. In other words, at the limit of the displacement range of the stage  130  (i.e. at the position of the maximum displacement of the stage  130 ), the displacement direction of the stage  130  changes from a positive direction to a negative direction (e.g. an upward direction in  FIG. 5  to a downward direction in  FIG. 5 ), or from the negative direction to the positive direction (e.g. the downward direction in  FIG. 5  to the upward direction in  FIG. 5 ). Thus, from the viewpoint of performing the stable recording operation and reproduction operation, it is preferable not to perform the recording operation and reproduction operation using the probes  12  near the limit of the displacement range of the stage  130 . This holds true in the second example and the like explained below. 
     Moreover, in the explanation of the driving apparatus  100   a  in the first example described above, the stage  130  is displaced by applying the excitation force caused by the piezoelectric effect to the base  110 . However, in addition to or instead of the excitation force caused by the piezoelectric effect, the excitation force caused by the electromagnetic force or the excitation force caused by the electrostatic force may be applied to the base  110 . Here, with reference to  FIG. 7  and  FIG. 8 , an explanation will be given on the structures of a driving apparatus  100   b  in which the stage  130  is displaced by applying the excitation force caused by the electromagnetic force to the base  110  and a driving apparatus  100   c  in which the stage  130  is displaced by applying the excitation force caused by the electrostatic force to the base  110 .  FIG. 7  is a plan view conceptually showing the structure of the driving apparatus  100   b  in which the stage  130  is displaced by applying the excitation force caused by the electromagnetic force to the base  100 .  FIG. 8  is a plan view conceptually showing the structure of the driving apparatus  100   c  in which the stage  130  is displaced by applying the excitation force caused by the electrostatic force to the base  110 . 
     As shown in  FIG. 7 , the driving apparatus  100   b  is provided with the base  110 , the two suspensions  120 , and the stage  130 , as in the driving apparatus  100   a . The driving apparatus  100   b  is provided particularly with a coil  151  and a magnetic pole  152  at least one of which is fixed to the base  110 , instead of the electrode  141 , the piezoelectric element  142 , and the electrode  143  provided for the driving apparatus  100   a . To the coil  151 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . The application of the voltage to the coil  151  causes electromagnetic interaction between the coil  151  and the magnetic pole  152 . As a result, an electromagnetic force by the electromagnetic interaction is generated. Here, since at least one of the coil  151  and the magnetic pole  152  is fixed to the base  110 , a force caused by the electromagnetic force is applied to the base  110 . In other words, in the driving apparatus  100   b , the force caused by the electromagnetic force is applied to the base  110  as the excitation force. As a result, the stage  130  oscillates (i.e. is displaced) in the Y-axis direction. 
     Even in such a driving apparatus  100   b , it is possible to receive substantially the same effects as those received by the driving apparatus  100   a  in which the aforementioned excitation force caused by the piezoelectric effect is applied to the base  110 . 
     As shown in  FIG. 8 , the driving apparatus  100   c  is provided with the base  110 , the two suspensions  120 , and the stage  130 , as in the driving apparatus  100   a . The driving apparatus  100   c  is provided particularly with an electrode  161  and an electrode  162  which is fixed to the base  110  and which is grounded, instead of the electrode  141 , the piezoelectric element  142 , and the electrode  143  provided for the driving apparatus  100   a . The electrode  161  and the electrode  162  are disposed with a predetermined distance therebetween. To the electrode  161 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . Here, due to a potential difference between the electrode  161  and the electrode  162 , an electrostatic force (in other words, Coulomb force) is generated between the electrode  161  and the electrode  162 . Here, since the electrode  162  is fixed to the base  110 , a force caused by the electrostatic force is applied to the base  110 . In other words, in the driving apparatus  100   c , the force caused by the electrostatic force is applied to the base  110  as the excitation force. As a result, the stage  130  oscillates (i.e. is displaced) in the Y-axis direction. 
     Even in such a driving apparatus  100   c , it is possible to receive substantially the same effects as those received by the driving apparatus  100   a  in which the aforementioned excitation force caused by the piezoelectric effect is applied to the base  110 . 
     Incidentally, considering that the base  110  rarely oscillates, the structure for applying the excitation force to the base  110  does not require such a large force as the excitation force. Moreover, in comparison to the excitation force caused by the piezoelectric effect and the excitation force caused by the electromagnetic force, the excitation force caused by the electrostatic force is generally small. Thus, the structure for applying the excitation force to the base  110  preferably applies the excitation force caused by the electrostatic force. 
     Incidentally, a combination of the actuator drive circuit  22 , the electrode  141 , the piezoelectric element  142 , and the electrode  143  constitutes one specific example of the “applying device” of the present invention. Moreover, a combination of the actuator drive circuit  22 , the coil  151 , and the magnetic pole  152  constitutes one specific example of the “applying device” of the present invention. Moreover, a combination of the actuator drive circuit  22 , the electrode  161 , and the electrode  162  constitutes one specific example of the “applying device” of the present invention. 
     (2-1-2) Second Example of Driving Apparatus 
     Next, with reference to  FIG. 9 , a driving apparatus  100   d  in a second example will be explained.  FIG. 9  is a plan view conceptually showing the structure of the driving apparatus  100   d  in a second example. Incidentally, the same constituents as those of the driving apparatus  100   a  in the first example described above (and moreover, the driving apparatus  100   b  and the driving apparatus  100   c ) will carry the same referential numerals, and the detailed explanation thereof will be omitted. 
     As shown in  FIG. 9 , the driving apparatus  100   d  in the second example is provided with the base  110 , the two suspensions  120 , the stage  130 , and two pairs of electrodes  141 , piezoelectric elements  142 , and electrodes  143 , which correspond to the two suspensions, as in the driving apparatus  100   a  in the first example. 
     In the driving apparatus  100   d  in the second example, in particular, the excitation force caused by the change of the shape of the piezoelectric element  142  due to the application of the voltage (i.e. the piezoelectric element) is applied to the two suspensions  120  instead of the base  110 . Moreover, the driving apparatus  100   d  is provided with two pairs of force transmission mechanisms  144  for amplifying the amount of displacement by the excitation force. The force transmission mechanism  144  uses the principle of leverage and is adapted to amplify the amount of displacement by the excitation force to several times to several ten times. Moreover, even in the driving apparatus  100   d  in the second example, as in the driving apparatus  100   a  in the first example, the excitation force that can displace the stage  130  is applied in timing according to the resonance frequency determined by the two suspensions  120  and the stage  130 . By this, the two suspensions  120  to which the excitation force is applied start to oscillate. As a result, the stage  130  which is fixed to the other edges of the two suspensions  120  is resonated (i.e. is displaced) in the Y-axis direction. 
     By this, even in the driving apparatus  100   d  in the second example, it is possible to receive the same effects as those received by the driving apparatus  100   a  in the first example. In other words, it is possible to reduce the electric energy which is necessary to apply the excitation force necessary for the displacement of the stage  130  to the two suspensions  120 . Therefore, it is possible to displace the stage  130  more efficiently, resulting in the lower power consumption of the driving apparatus  100   d . Moreover, since the behavior of the oscillation system including the stage  130  and the two suspensions  120 , which is the resonance, is used to displace the stage  130 , it is possible to preferably maintain the stability of the position of the stage  130 . As a result, it is possible to preferably obtain the repeatability with respect to aspects of the displacement of the stage  130 . As a result, it is possible to record the data at a desired position on the recording medium  30 , or to reproduce the data recorded at the desired position on the recording medium  30 . 
     In addition, in the driving apparatus  100   d  in the second example, the excitation force is applied to the two suspensions  120 . Here, if points of the two suspensions  120  to which the excitation force is applied are regarded as points of effort, if points of the two suspensions  120  to which the base  110  is fixed are regarded as the fulcrums, and if points of the two suspensions  120  to which the stage  130  is fixed are regarded as points of load, it can be seen that the stage  130  is resonated by using the principle of leverage. In other words, in the driving apparatus  100   d  in the second example, the two suspensions  120  are used as levers. By this, by virtue of the excitation force that realizes the amount of displacement that is relatively small, it is possible to displace the stage  130  relatively greatly. 
     Considering that the two suspensions  120  are used as levers, as described above, a distance between the points to which the excitation force is applied and the points at which the two suspensions  120  and the stage  130  are fixed is preferably greater than a distance between the points to which the excitation force is applied and the points at which the two suspensions  120  and the base  110  are fixed. In other words, the points to which the excitation force is applied are preferably close to the points at which the two suspensions  120  and the base  110  are fixed. As the points to which the excitation force is applied are closer to the points at which the two suspensions  120  and the base  110  are fixed, it is possible to displace the stage  130  relatively greatly by the excitation force that realizes the smaller amount of displacement. 
     Incidentally, from the viewpoint that the excitation force is simply applied, the driving apparatus  100   d  in the second example is not necessarily provided with the force transmission mechanisms  144 . However, considering that the amount of change of the shape of the piezoelectric element  142  due to the application of the voltage is relatively small and that it is necessary to actually oscillate (i.e. displace) the two suspensions  120  by the excitation force, it is preferable to amplify the amount of change of the shape of the piezoelectric element  142  by using the force transmission mechanisms  144  and to apply the excitation force caused by the amplified amount of change to the two suspensions  120 . 
     Incidentally, in the second example, the stage  130  is displaced by applying the excitation force caused by the piezoelectric effect to the two suspensions  120 . However, even in the second example, as in the first example, in addition to or instead of the excitation force caused by the piezoelectric effect, the excitation force caused by the electromagnetic force and the excitation force caused by the electrostatic force may be applied to the two suspensions  120 . Here, with reference to  FIG. 10  and  FIG. 11 , an explanation will be given on a driving apparatus  100   e  in which the stage  130  is displaced by applying the excitation force caused by the electromagnetic force to the two suspensions  120  and a driving apparatus  100   f  in which the stage  130  is displaced by applying the excitation force caused by the electrostatic force to the two suspensions  120 .  FIG. 10  is a plan view conceptually showing the structure of the driving apparatus  100   e  in which the stage  130  is displaced by applying the excitation force caused by the electromagnetic force to two suspensions  120 .  FIG. 11  is a plan view conceptually showing the structure of the driving apparatus  100   f  in which the stage  130  is displaced by applying the excitation force caused by the electrostatic force to the two suspensions  120 . 
     As shown in  FIG. 10 , the driving apparatus  100   e  is provided with two pairs of coils  151  and magnetic poles  152  at least one of which is fixed to the corresponding suspension  120  of the two suspensions  120 , instead of the two pairs of electrodes  141 , piezoelectric elements  142 , electrodes  143 , and force transmission mechanisms  144  which are provided for the driving apparatus  100   d , as in the aforementioned driving apparatus  100   b . In this case, the other of the coil  151  and the magnetic pole  152  that are not fixed to the corresponding suspension  120  may be fixed to the base  110 . To each of the coils  151 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . By this, in the driving apparatus  100   e , a force caused by the electromagnetic force is applied to the two suspensions  120  as the excitation force. As a result, the stage  130  oscillates (i.e. is displaced) in the Y-axis direction. Even in such a driving apparatus  100   e , it is possible to receive substantially the same effects as those received by the driving apparatus  100   d  in which the aforementioned excitation force caused by the piezoelectric effect is applied to the two suspensions  120 . 
     As shown in  FIG. 11 , the driving apparatus  100   f  is provided with a plurality of electrodes  161  each of which is fixed to the base  110  and a plurality of electrodes  162  each of which is fixed to the corresponding suspension  120  of the two suspensions  120  and each of which is grounded, instead of the two pairs of electrodes  141 , piezoelectric elements  142 , electrodes  143 , and force transmission mechanisms  144  which are provided for the driving apparatus  100   d , as in the aforementioned driving apparatus  100   c . In particular, one of the plurality of electrodes  162  arranged in a comblike manner is disposed between two of the plurality of electrodes  161  arranged in a comblike manner. To each of the plurality of electrodes  161 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . By this, in the driving apparatus  100   f , a force caused by the electrostatic force is applied to the two suspensions  120  as the excitation force. As a result, the stage  130  oscillates (i.e. is displaced) in the Y-axis direction. Even in such a driving apparatus  100   f , it is possible to receive substantially the same effects as those received by the driving apparatus  100   d  in which the aforementioned excitation force caused by the piezoelectric effect is applied to the two suspensions  120 . 
     (2-1-3) Third Example 
     Next, with reference to  FIG. 12 , a driving apparatus  100   g  in a third example will be explained.  FIG. 12  is a plan view conceptually showing the structure of the driving apparatus  100   g  in the third example. Incidentally, the same constituents as those of the driving apparatus  100   a  in the first example described above (and moreover, the driving apparatus  100   b  and the driving apparatus  100   c ) and the driving apparatus  100   d  in the second example (and moreover, the driving apparatus  100   e  and the driving apparatus  100   f ) will carry the same referential numerals, and the detailed explanation thereof will be omitted. 
     As shown in  FIG. 12 , the driving apparatus  100   d  in the third example is provided with the base  110 , the two suspensions  120 , the stage  130 , and the two pairs of electrodes  141 , piezoelectric elements  142 , electrodes  143 , and force transmission mechanisms  144 , as in the driving apparatus  100   d  in the second example. 
     In the driving apparatus  100   g  in the third example, in particular, the excitation force caused by the change of the shape of the piezoelectric element  142  due to the application of the voltage (i.e. the piezoelectric element) is applied directly to the stage  130  instead of the base  110  and the two suspensions  120 . Moreover, even in the driving apparatus  100   g  in the third example, the excitation force is applied that can resonate the stage  130  at the resonance frequency determined by the two suspensions  120  and the stage  130 , as in the driving apparatus  100   a  in the first example and the driving apparatus  100   d  in the second example. By this, the stage  130  to which the excitation force is applied is resonated (i.e. is displaced) in the Y-axis direction. 
     By this, even in the driving apparatus  100   g  in the third example, it is possible to receive the same effects as those received by the driving apparatus  100   a  in the first example. In other words, it is possible to reduce the electric energy which is necessary to apply the excitation force, which is necessary for the displacement of the stage  130 , to the stage  130 . Therefore, it is possible to displace the stage  130  more efficiently, resulting in the lower power consumption of the driving apparatus  100   g . Moreover, since the behavior of the oscillation system including the stage  130  and the two suspensions  120 , which is the resonance, is used to displace the stage  130 , it is possible to preferably maintain the stability of the position of the stage  130 . As a result, it is possible to preferably obtain the repeatability with respect to aspects of the displacement of the stage  130 . As a result, it is possible to record the data at a desired position on the recording medium  30 , or to reproduce the data recorded at the desired position on the recording medium  30 . 
     Moreover, since the excitation force is applied to the stage  130 , if the excitation force is applied in timing according to the displacement of the stage  130 , i.e. intermittently, it is possible to resonate the stage  130 . Specifically, although the distance between the force transmission mechanisms  144  and the stage  130  varies depending on the displacement of the stage  130 , if the excitation force is applied when the force transmission mechanisms  144  and the stage  130  are in contact, it is possible to resonate the stage  130 . Thus, it is no longer necessary to apply the excitation force all the time, so that it is possible to further reduce the electric energy which is necessary to apply the excitation force. 
     Incidentally, in the third example, the stage  130  is displaced by applying the excitation force caused by the piezoelectric effect to the stage  130 . However, even in the third example, in addition to or instead of the excitation force caused by the piezoelectric effect as in the first and second examples, the excitation force caused by the electromagnetic force and the excitation force caused by the electrostatic force may be applied to the stage  130 . Here, with reference to  FIG. 13  and  FIG. 14 , an explanation will be given on a driving apparatus  100   h  in which the stage  130  is displaced by applying the excitation force caused by the electromagnetic force to the stage  130  and a driving apparatus  100   i  in which the stage  130  is displaced by applying the excitation force caused by the electrostatic force to the stage  130 .  FIG. 13  is a plan view conceptually showing the structure of the driving apparatus  100   h  in which the stage  130  is displaced by applying the excitation force caused by the electromagnetic force to the stage  130 .  FIG. 14  is a plan view conceptually showing the structure of the driving apparatus  100   i  in which the stage  130  is displaced by applying the excitation force caused by the electrostatic force to the stage  130 . 
     As shown in  FIG. 13 , the driving apparatus  100   h  is provided with two pairs of coils  151  and magnetic poles  152  at least ones of which are fixed to the stage  130 , instead of the two pairs of electrodes  141 , piezoelectric elements  142 , electrodes  143 , and force transmission mechanisms  144  which are provided for the driving apparatus  100   g , as in the driving apparatus  100   b  and the driving apparatus  100   e  described above. In this case, the others of the coil  151  and the magnetic pole  152  that are not fixed to the stage  130  may be fixed to the base  110 . To each of the coils  151 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . By this, in the driving apparatus  100   h , a force caused by the electromagnetic force is applied to the stage  130  as the excitation force. As a result, the stage  130  oscillates (i.e. is displaced) in the Y-axis direction. Even in such a driving apparatus  100   h , it is possible to receive substantially the same effects as those received by the driving apparatus  100   g  in which the aforementioned excitation force caused by the piezoelectric effect is applied to the stage  130 . 
     As shown in  FIG. 14 , the driving apparatus  100   i  is provided with a plurality of electrodes  161  each of which is fixed to the base  110  and a plurality of electrodes  162  each of which is fixed to the stage  130  and each of which is grounded, instead of the two pairs of electrodes  141 , piezoelectric elements  142 , electrodes  143 , and force transmission mechanisms  144  which are provided for the driving apparatus  100   g , as in the driving apparatus  100   c  and the driving apparatus  100   f  described above. In particular, one of the plurality of electrodes  162  arranged in a comblike manner is disposed between two of the plurality of electrodes  161  arranged in a comblike manner. To each of the electrodes  161 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . By this, in the driving apparatus  100   i , a force caused by the electrostatic force is applied to the stage  130  as the excitation force. Even in such a driving apparatus  100   i , it is possible to receive substantially the same effects as those received by the driving apparatus  100   g  in which the aforementioned excitation force caused by the piezoelectric effect is applied to the stage  130 . 
     (2-1-4) Fourth Example 
     Next, with reference to  FIG. 15  and  FIG. 16 , a driving apparatus  100   j  in a fourth example will be explained.  FIG. 15  is a plan view conceptually showing the structure of the driving apparatus  100   j  in the fourth example.  FIG. 16  is a plan view conceptually showing an aspect when the driving apparatus  100   j  in the fourth example operates. Incidentally, the same constituents as those of the driving apparatus  100   a  in the first example described above (and moreover, the driving apparatus  100   b  and the driving apparatus  100   c ), the driving apparatus  100   d  in the second example (and moreover, the driving apparatus  100   e  and the driving apparatus  100   f ), and the driving apparatus  100   g  in the third example (and moreover, the driving apparatus  100   h  and the driving apparatus  100   i ) will carry the same referential numerals, and the detailed explanation thereof will be omitted. 
     As shown in  FIG. 15 , the driving apparatus  100   j  in the fourth example is provided with the base  110 , the two suspensions  120 , the stage  130 , the plurality of electrodes  161  each of which is fixed to the base  110 , and the plurality of electrodes  162  each of which is fixed to the stage  130  and each of which is grounded, as in the driving apparatus  100   i  in the third example (refer to  FIG. 14 ). 
     Particularly, the driving apparatus  100   j  in the fourth example is provided with two spring constant adjustment devices  170  corresponding to the two suspensions  120 . Each of the two spring constant adjustment devices  170  is provided with a predetermined member  171  which can be freely attached to and detached from the corresponding suspension  120  of the two suspensions  120  and a spring  172  for applying a force to attach the member  171  to the corresponding suspension  120  or to detach the member  171  from the corresponding suspension  120 . 
     The spring  172  extends in response to a control signal outputted from the actuator drive circuit  22 . As a result, the member  171  is attached to the corresponding suspension  120 . In other words, as shown in  FIG. 16 , the member  171  and the corresponding suspension  120  are unified. This results in a change of the spring constant of each of the two suspensions  120 . On the other hand, the spring  172  contracts in response to the control signal outputted from the actuator drive circuit  22 . As a result, the member  171  is detached from the corresponding suspension  120 . In other words, the member  171  and the corresponding suspension  120  which are unified are detached. This results in a change of the spring constant of each of the two suspensions  120 . 
     This changes the resonance frequency determined by the two suspensions  120  and the stage  130 , so that it is possible to resonate the stage  130  at a desired frequency. 
     Incidentally, in addition to or instead of changing the resonance frequency by adjusting the spring constant of the two suspensions  120 , the mass of the stage  130  may be adjusted to change the resonance frequency. Here, the structure of a driving apparatus  100   k  in which the mass of the stage  130  is adjusted will be explained with reference to  FIG. 17 .  FIG. 17  is a plan view conceptually showing the structure of the driving apparatus  100   k  in which the mass of the stage  130  is adjusted. 
     As shown in  FIG. 17 , the driving apparatus  100   k  is provided with the base  110 , the two suspensions  120 , the stage  130 , the plurality of electrodes  161  each of which is fixed to the base  110 , the plurality of electrodes  162  each of which is fixed to the stage  130  and each of which is grounded, as in the aforementioned driving apparatus  100   j , and a stage mass adjustment device  173 . The stage mass adjustment device  173  is provided with a predetermined member  171  which can be freely attached to and detached from the stage  130  and a spring  172  for applying a force to attach the member  171  to the stage  130  or to detach the member  171  from the stage  130 . 
     The spring  172  extends in response to a control signal outputted from the actuator drive circuit  22 . As a result, the member  171  is attached to the stage  130 . In other words, the member  171  and the stage  130  are unified. This results in a change of the mass of the stage  130 . On the other hand, the spring  172  contracts in response to the control signal outputted from the actuator drive circuit  22 . As a result, the member  171  is detached from the stage  130 . In other words, the member  171  and the stage  130  which are unified are detached. This results in a change of the mass of the stage  130 . 
     This changes the resonance frequency determined by the two suspensions  120  and the stage  130 , so that it is possible to resonate the stage  130  at a desired frequency. 
     Incidentally, in the fourth example, the spring  172  is presented as a driving force generation member for applying, to the member  171 , the force for attaching and detaching the member  171  with respect to the stage  130  or the corresponding suspension  120 . Instead of the spring  172 , however, a driving force generation member which uses the electrostatic force, the electromagnetic force, and the like may be adopted. 
     Incidentally, the aforementioned explanation describes the structure that is realized by combining the constituents for adjusting the resonance frequency with respect to the driving apparatus  100   i  in the third example. However, it is obvious that the constituents for adjusting the resonance frequency may be combined with respect to the other driving apparatus  100   g  or driving apparatus  100   h  in the third example. In the same manner, it is obvious that the constituents for adjusting the resonance frequency may be combined with respect to the other driving apparatuses  100   a  to  100   c  in the first example or the driving apparatuses  100   d  to  100   f  in the second example. 
     (2-2) Driving Apparatus Adopting Biaxial Driving Method 
     Next, with reference to  FIG. 18  to  FIG. 30 , of the driving apparatus  100  in the examples, driving apparatuses adopting a biaxial driving method (specifically, driving apparatuses in a fifth example to an eighth example, described later) will be described. Incidentally, the driving apparatus adopting the biaxial driving method is a driving apparatus that can displace the probes  12  along two axes (e.g. X axis and Y axis). In other words, the driving apparatus adopting the biaxial driving method is a driving apparatus that can realize the two-dimension displacement of the probes  12 . 
     Incidentally, the same constituents as those of the driving apparatus  100   a  in the first example (an moreover, the driving apparatus  100   b  and the driving apparatus  100   c ), the driving apparatus  100   d  in the second example (an moreover, the driving apparatus  100   e  and the driving apparatus  1000 , the driving apparatus  100   g  in the third example (an moreover, the driving apparatus  100   h  and the driving apparatus  1000 , and the driving apparatus  100   j  in the fourth example (an moreover, the driving apparatus  100   k ) described above will carry the same numerical references, and the detailed explanation thereof will be omitted. 
     (2-2-1) Fifth Example of Driving Apparatus 
     Firstly, with reference to  FIG. 18  to  FIG. 20 , a driving apparatus  100   l  in a fifth example will be explained.  FIG. 18  is a plan view conceptually showing the structure of the driving apparatus  100   l  in the fifth example.  FIG. 19  is a plan view conceptually showing an aspect when a first stage  130 - 1  of the driving apparatus  100   l  in the fifth example shown in  FIG. 18  is displaced.  FIG. 20  is a plan view conceptually showing another aspect when a second stage  130 - 2  of the driving apparatus  100   l  in the fifth example shown in  FIG. 18  is displaced. 
     As shown in  FIG. 18 , the driving apparatus  100   l  in the fifth example is provided with first bases  110 - 1 , first suspensions  120 - 1  which are fixed to the first bases  110 - 1  at their one edges and which can extend and contract in an X-axis direction, a first stage  130 - 1  to which the other edges of the first suspensions  120 - 1  are fixed, second suspensions  120 - 2  which are fixed to the first stage  130 - 1  at their one edges and which can expand and contract in a Y-axis direction, and a second stage  130 - 2  to which the other edges of the second suspensions  120 - 2  are fixed and which is provided with the plurality of probes  12 . As described above, in the driving apparatus  100   l  in the fifth example, the first stage  130 - 1  is supported by the two first suspensions  120 - 1 , and the second stage  130 - 2  is supported by the two second suspensions  120 - 2 . Moreover, the driving apparatus  100   l  in the fifth example is provided with the plurality of electrodes  161  each of which is fixed to respective one of the first bases  110 - 1  and the plurality of electrodes  162  each of which is fixed to the first stage  130 - 1  and each of which is grounded. Moreover, the driving apparatus  100   l  in the fifth example is provided with the electrode  141 , the electrode  143  which is fixed to the first stage  130 - 1  and which is grounded, and the piezoelectric element  142  which is disposed between the electrode  141  and the electrode  143 . Incidentally, the first base  110 - 1 , the first suspension  120 - 1 , the plurality of electrodes  161 , and the plurality of electrodes  162  are disposed on each of the left and right sides of the first stage  130 - 1 . Moreover, the second suspension  120 - 2  is disposed on each of the upper and lower sides of the second stage  130 - 2 . In other words, the driving apparatus  100   l  in the fifth example is provided with two pairs of the first bases  110 - 1 , two pairs of the first suspensions  120 - 1 , two pairs of the plurality of electrodes  161 , and two pairs of the plurality of electrodes  162 . In the same manner, the driving apparatus  100   l  in the fifth example is provided with two pairs of the second suspensions  120 - 2 . 
     Here, an explanation will be given on the operations of the driving apparatus  100   l  in the fifth example having the aforementioned structure. Firstly, to each of the plurality of electrodes  161 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . By this, a force caused by the electrostatic force is applied to the first stage  130 - 1  as the excitation force. As a result, the first stage  130 - 1  oscillates (i.e. is displaced) in the X-axis direction by using the elasticity of the first suspensions  120 - 1 , as shown in  FIG. 19 . 
     At this time, the actuator drive circuit  22  applies the desired voltage to each of the plurality of electrodes  161  in the desired timing such that the force for displacing the first stage  130 - 1  is applied in a stepwise manner or in a continuous manner by a predetermined amount. 
     Incidentally, in the explanation below, the force applied to the base  110  (or the suspensions  120  or the stage  130  as described later) for displacing the stage  130  in the stepwise manner or in the continuous manner by the predetermined amount (in other words, for displacing the stage  130  in an aspect other than the aspect of oscillating the stage  130  at the resonance frequency) is referred to as a “driving force”. 
     More specifically, the actuator drive circuit  22  applies the desired voltage to each of the plurality of electrodes  161  in the desired timing such that the driving force for realizing a tracking operation on the recording surface of the recording medium  30  by the displacement of the first stage  130 - 1  is applied. For example, if the pitch of the data (i.e. track pitch) recorded on the recording medium  30  is t, the desired voltage is applied to each of the plurality of electrodes  161  in the desired timing so as to apply the driving force for displacing the first stage  130 - 1  by the distance t or distance Lt (wherein L is an integer of 1 or more). As a result, the first stage  130 - 1  is displaced in the stepwise manner or in the continuous manner by the predetermined amount. 
     On the other hand, to the electrode  141 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . By this, a force caused by a change of the shape of the piezoelectric element  142  (i.e. the piezoelectric effect) is applied to the first stage  130 - 1  as the excitation force. By this, the two suspensions  120 - 2  which are fixed to the first stage  130 - 1  at their one edges start to oscillate. As a result, the second stage  130 - 2  which is fixed to the other edges of the two second suspensions  120 - 2  oscillates (i.e. is displaced) in the Y-axis direction by using the elasticity of the second suspensions  120 - 2 , as shown in  FIG. 20 . 
     At this time, the actuator drive circuit  22  applies the desired voltage to the electrode  141  in the desired timing so as to apply the excitation force for oscillating (i.e. resonating) the second stage  130 - 2  at the resonance frequency determined by the two second suspensions  120 - 2  and the second stage  130 - 2 . In particular, the actuator drive circuit  22  applies the desired voltage to the electrode  141  in the desired timing so as to apply the excitation force for resonating the second stage  130 - 2 , with the first stage  130 - 1  as a reference position. As a result, the second stage  130 - 2  is resonated at the resonance frequency determined by the two second suspensions  120 - 2  and the second stage  130 - 2 , if it is viewed as a relative position to the first stage  130 - 1 . 
     As described above, in the driving apparatus  100   l  in the fifth example, it is possible to displace the second stage  130 - 2  in the X-axis direction while resonating it in the Y-axis direction, by displacing the first stage  130 - 1  in the X-axis direction and by resonating the second stage  130 - 2  disposed on the first stage  130 - 1  in the Y-axis direction. In other words, it is possible to biaxially drive the second stage  130 - 2  (i.e. the plurality of probes  12  disposed on the second stage  130 - 2 ). Thus, it is possible to record the data onto the substantially entire recording surface on the recording medium  30  having a rectangular shape, or to reproduce the data recorded on the substantially entire recording surface on the recording medium  30 , by using the plurality of probes  12 . 
     Moreover, even in the driving apparatus  100   l  in the fifth example, the second stage  130 - 2  is displaced in the Y-axis direction by using the resonance as in the aforementioned driving apparatus  100   a  in the first example and the like, so that it is possible to receive the same effects as those received by the driving apparatus  100   a  in the first example. In other words, it is possible to reduce the electric energy which is necessary to apply the excitation force necessary for the displacement of the second stage  130 - 2  to the first stage  130 - 1 . Therefore, it is possible to displace the second stage  130 - 2  more efficiently, resulting in the lower power consumption of the driving apparatus  100   l . Moreover, since the behavior of the oscillation system including the second stage  130 - 2  and the two second suspensions  120 - 2 , which is the resonance, is used to displace the second stage  130 - 2 , it is possible to preferably maintain the stability of the position of the second stage  130 - 2 . As a result, it is possible to preferably obtain the repeatability with respect to aspects of the displacement of the second stage  130 - 2 . As a result, it is possible to record the data at a desired position on the recording medium  30 , or to reproduce the data recorded at the desired position on the recording medium  30 . 
     Incidentally, in the driving apparatus  100   l  in the fifth example, if one of the first bases  110 - 1 , one of the first suspensions  120 - 1 , and the first stage  130 - 1  are regarded as one driving apparatus, it is possible to read, from the explanations and corresponding drawings described above, that the one driving apparatus including the one first base  110 - 1 , the one first suspension  120 - 1 , and the first stage  130 - 1  has substantially the same structure as the aforementioned driving apparatus adopting the uniaxial driving method (in particular, the driving apparatus  100   i  in the third example). Moreover, if the first stage  130 - 1 , one of the second suspensions  120 - 2 , and the second stage  130 - 2  are regarded as one driving apparatus, it is possible to read, from the explanations and corresponding drawings described above, that the driving apparatus including the first stage  130 - 1 , the one second suspension  120 - 2 , and the second stage  130 - 2  has substantially the same structure as the aforementioned driving apparatus adopting the uniaxial driving method (in particular, the driving apparatus  100   a  in the first example). In other words, the first stage  130 - 1  functions as the aforementioned stage  130  in the driving system including the first stage  130 - 1 , the first suspension  120 - 1 , and the first stage  130 - 1 , whereas the first stage  130 - 1  functions as the aforementioned base  110  in the driving system including the first stage  130 - 1 , the second suspension  120 - 2 , and the second stage  130 - 2 . 
     However, a second base  110 - 2  may be further disposed on the first stage  130 - 1 , and the second suspensions  120 - 2  and the second stage  130 - 2  may be further disposed on the second base  110 - 2 . Even in such construction, obviously, it is possible to preferably receive the aforementioned various effects. 
     Moreover, in the explanation about the driving apparatus  100   l  in the fifth example described, the second stage  130 - 2  is displaced in the Y-axis direction by applying the excitation force caused by the piezoelectric effect to the first stage  130 - 1 . However, in addition to or instead of the excitation force caused by the piezoelectric effect, the excitation force caused by the electromagnetic force and the excitation force caused by the electrostatic force may be applied to the first stage  130 - 1 . Here, with reference to  FIG. 21  and  FIG. 22 , an explanation will be given on a driving apparatus  100   m  in which the second stage  130 - 2  is displaced in the Y-axis direction by applying the excitation force caused by the electromagnetic force to the first stage  130 - 1  and a driving apparatus  100   n  in which the second stage  130 - 2  is displaced in the Y-axis direction by applying the excitation force caused by the electrostatic force to the first stage  130 - 1 .  FIG. 21  is a plan view conceptually showing the structure of the driving apparatus  100   m  in which the second stage  130 - 2  is displaced in the Y-axis direction by applying the excitation force caused by the electromagnetic force to the first stage  130 - 1 .  FIG. 22  is a plan view conceptually showing the structure of the driving apparatus  100   n  in which the second stage  130 - 2  is displaced in the Y-axis direction by applying the excitation force caused by the electrostatic force to the first stage  130 - 1 . Incidentally, here, the structure for applying the “excitation force” is explained; however, it is obvious that the structure for applying the “driving force” may also use the piezoelectric effect, the electromagnetic force, and the electrostatic force. 
     As shown in  FIG. 21 , the driving apparatus  100   m  is provided with the coil  151  and the magnetic pole  152  at least one of which is fixed to the first stage  130 - 1 , instead of the electrode  141 , the piezoelectric element  142 , and the electrode  143  provided for the driving apparatus  100   l , as in the driving apparatus  100   b , the driving apparatus  100   e , and the driving apparatus  100   h  described above. To the coil  151 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . By this, in the driving apparatus  100   m , a force caused by the electromagnetic force is applied to the first stage  130 - 1  as the excitation force. As a result, the second stage  130 - 2  oscillates (i.e. is displaced) in the Y-axis direction. Even in such a driving apparatus  100   m , it is possible to receive substantially the same effects as those received by the driving apparatus  100   l  in which the aforementioned excitation force caused by the piezoelectric effect is applied to the first stage  130 - 1 . 
     As shown in  FIG. 22 , the driving apparatus  100   n  is provided with the electrode  161  and the electrode  162  which is fixed to the first stage  130 - 1  and which is grounded, instead of the electrode  141 , the piezoelectric element  142 , and the electrode  143  provided for the driving apparatus  100   l , as in the driving apparatus  100   c , the driving apparatus  100   f , and the driving apparatus  100   i  described above. To the electrode  161 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . By this, in the driving apparatus  100   n , a force caused by the electrostatic force is applied to the first stage  130 - 1  as the excitation force. As a result, the second stage  130 - 2  oscillates (i.e. is displaced) in the Y-axis direction. Even in such a driving apparatus  100   n , it is possible to receive substantially the same effects as those received by the driving apparatus  100   l  in which the aforementioned excitation force caused by the piezoelectric effect is applied to the first stage  130 - 1 . 
     Incidentally, considering that the excitation force caused by the electrostatic force is relatively small, the structure for applying the excitation force caused by the electrostatic force to the first stage  130 - 1  as shown in  FIG. 22  may be provided with two types of driving sources for displacing the second stage  130 - 2  in the Y-axis direction. The structure will be explained with reference to  FIG. 23 .  FIG. 23  is a plan view conceptually showing the structure of a driving apparatus  100   o  provided with the two types of driving sources for displacing the second stage  130 - 2  in the Y-axis direction. 
     As shown in  FIG. 23 , the driving apparatus  100   o  has the same structure as the above described driving apparatus  100   n . Particularly, the driving apparatus  100   o  is provided with two pairs of coils  151  and magnetic poles  152  at least ones of which are fixed to the second stage  130 - 2 . In this case, the others of the coil  151  and the magnetic pole  152  that are not fixed to the second stage  130 - 2  may be fixed to the first stage  130 - 1 . To each of the coils  151 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . By this, in the driving apparatus  100   o , a force caused by the electromagnetic force can be applied to the second stage  130 - 2  as the excitation force. In other words, in the driving apparatus  100   o , each of the excitation force caused by the electrostatic force and the excitation force caused by the electromagnetic force can be applied to the second stage  130 - 2 . 
     Here, in the driving apparatus  100   o , at an initial stage at which the second stage  130 - 2  starts to be resonated (i.e. in a predetermined period from the start of the resonance of the second stage  130 - 2 ), the excitation force caused by the electromagnetic force is applied to the second stage  130 - 2 . Then, after the initial stage, the excitation force caused by the electromagnetic forced is applied to the second stage  130 - 2 , as the excitation force to maintain the resonance of the second stage  130 - 2 . 
     By this, it is possible to start to resonate the second stage  130 - 2  by using the relatively large excitation force caused by the electromagnetic force, and if the behavior of the second stage  130 - 2  is stabilized, it is also possible to maintain the resonance of the second stage  130 - 2  by using the relatively small excitation force caused by the electrostatic force. Thus, it is possible to resonate the second stage  130 - 2  more efficiently. 
     Moreover, it is possible to minimize the application of the voltage to the coils  151  which are heat sources for the second stage  130 - 2 . In other words, it is possible to relatively limit or control heat generation caused by the coils  151  as the driving sources, in the movable portion including the two second suspensions  120 - 2  and the second stage  130 - 2 . As a result, it is possible to preferably limit or control an adverse effect of the heat on the movable portion including the two second suspensions  120 - 2  and the second stage  130 - 2 . 
     Incidentally, not only in the structure for applying the excitation force caused by the electrostatic force to the first stage  130 - 1  but also in the structure for applying the excitation force caused by the piezoelectric effect to the first stage  130 - 1  or the structure for applying the excitation force caused by the electromagnetic force to the first stage  130 - 1 , there may be provided with the two types of driving sources for displacing the second stage  130 - 2  in the Y-axis direction. 
     Moreover, the aforementioned driving apparatus  100   l  in the fifth example is provided with one second stage  130 - 2  on the first stage  130 - 1 ; however, it may be provided with a plurality of second stages  130 - 2  on the first stage  130 - 1 . In other words, the second stage  130 - 2  shown in  FIG. 18  may be divided. The structure will be explained with reference to  FIG. 24 .  FIG. 24  is a plan view conceptually showing the structure of a driving apparatus  100   p  provided with the plurality of second stages  130 - 2  on the first stage  130 - 1 . 
     As shown in  FIG. 24 , the driving apparatus  100   p  is provided with two pairs of first bases  110 - 1  and first suspensions  120 - 1 , the first stage  130 - 1 , the plurality of electrodes  161 , the plurality of electrodes  162 , the electrode  141 , the electrode  143 , and the piezoelectric element  142 , as in the aforementioned driving apparatus  100   l.    
     Particularly, the driving apparatus  100   p  is provided with four second stages  130 - 2  each of which has a relatively small size (specifically, each of which has a smaller size than the second stage  130 - 2  in the driving apparatus  100   l ), on the first stage  130 - 1 . To each of the four second stages  130 - 2 , the corresponding second suspension  120 - 2  is fixed at its other edge. To the first stage  130 - 1 , each of the four second suspension  120 - 2  is fixed at its one edge. 
     In the driving apparatus  100   p , the actuator drive circuit  22  applies a desired voltage to the electrode  141  in desired timing so as to apply the excitation force for oscillating (i.e. resonating) each of the second stages  130 - 2  at the resonance frequency determined by the corresponding second suspension  120 - 2  and each of the second stages  130 - 2 . As a result, each of the four second stages  130 - 2  is resonated at the resonance frequency determined by the corresponding second suspension  120 - 2  and each of the second stages  130 - 2 . 
     By this, even in the driving apparatus  100   p , it is possible to receive the same effects as those received by the driving apparatus  100   l  described above. 
     Moreover, since the size of each of the second stages  130 - 2  can be relatively reduced, it is possible to relatively reduce the mass of each of the second stages  130 - 2 . Thus, even if the size of the second suspension  120 - 2  for supporting each of the second stages  130 - 2  is reduced (e.g. even if its thickness or its width is reduced), it is possible to preferably support each of the second stages  130 - 2 . Therefore, it is possible to lighten or miniaturize the driving apparatus  100   p.    
     Incidentally, in the aforementioned driving apparatus  100   l  in the fifth example (and moreover, the driving apparatus  100   m  to the driving apparatus  100   p ), the driving system in which the second stage  130 - 2  is resonated adopts a structure for applying the excitation force to the first stage  130 - 2  (i.e. the same structure as in the first example for applying the excitation force to the base  110  described above). However, as in the aforementioned driving apparatus  100   d  in the second example (and moreover, the driving apparatus  100   e  and the driving apparatus  1000 , it is obvious that the excitation force may be applied to the second suspension  120 - 2 . In the same manner, as in the driving apparatus  100   g  in the third example (and moreover, the driving apparatus  100   e  and the driving apparatus  1000 , it is obvious that the excitation force may be applied to the second stage  130 - 2 . 
     Moreover, with respect to the aforementioned driving apparatus  100   l  in the fifth example (and moreover, the driving apparatus  100   m  to the driving apparatus  100   p ), obviously, the various structures explained in the first example to the fourth example described above may be applied, as occasion demands. In particular, it is effective to adjust the deviation of the amplitude, the resonance frequency, or the like of the plurality of stages  130  for more efficient adjustment of oscillation and amplitude, by incorporating the mechanism for adjusting the resonance frequency explained in the fourth example. 
     (2-2-2) Sixth Example 
     Next, with reference to  FIG. 25 , a driving apparatus  100   q  in a sixth example will be explained.  FIG. 25  is a plan view conceptually showing the structure of the driving apparatus  100   q  in the sixth example. 
     As shown in  FIG. 25 , the driving apparatus  100   q  in the sixth example is provided with the first base  110 - 1 , the first suspensions  120 - 1  which are fixed to the first base  110 - 1  at their one edges and which can expand and contract in the Y-axis direction, the first stage  130 - 1  to which the other edges of the first suspensions  120 - 1  are fixed, the second suspensions  120 - 2  which are fixed to the first stage  130 - 1  at their one edges and which can expand and contract in the X-axis direction, and the second stage  130 - 2  to which the other edges of the second suspensions  120 - 2  are fixed and which is provided with the plurality of probes  12 . As described above, in the driving apparatus  100   q  in the sixth example, the first stage  130 - 1  is supported by the two first suspensions  120 - 1 , and the second stage  130 - 2  is supported by the two second suspensions  120 - 2 . Moreover, the driving apparatus  100   q  in the sixth example is provided with coils  151 - 1  and magnetic poles  152 - 1  at least ones of which are fixed to the first stage  130 - 1 . In this case, the others of the coils  151 - 1  and the magnetic poles  152 - 1  that are not fixed to the first stage  130 - 1  may be fixed to the first base  110 - 1 . Moreover, the driving apparatus  100   q  in the sixth example is provided with coils  151 - 2  and magnetic poles  152 - 2  at least ones of which are fixed to the second stage  130 - 2 . In this case, the others of the coils  151 - 2  and the magnetic poles  152 - 2  that are not fixed to the second stage  130 - 2  are fixed to the first stage  130 - 1 . Incidentally, the first suspension  120 - 1  is disposed on each of the upper and lower sides of the first stage  130 - 1 . Moreover, the coils  151 - 1  and the magnetic poles  152 - 1  are disposed at symmetrical positions on the left and right sides of the first stage  130 - 1 . Moreover, the second suspension  120 - 2  is disposed on each of the left and right sides of the second stage  130 - 2 . Moreover, the coils  151 - 2  and the magnetic poles  152 - 2  are disposed at symmetrical positions on the upper and lower sides of the second stage  130 - 2 . 
     Here, an explanation will be given on the operation of the driving apparatus  100   q  in the sixth example having the aforementioned structure. Firstly, to each of the two coils  151 - 1 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . By this, a force caused by the electromagnetic force is applied to the first stage  130 - 1  as the excitation force. As a result, the first stage  130 - 1  oscillates (i.e. is displaced) in the Y-axis direction, by using the elasticity of the first suspension  120 - 1 . 
     At this time, the actuator drive circuit  22  applies the desired voltage to each of the two coils  151 - 1  in the desired timing so as to apply the excitation force for oscillating (i.e. resonating) the first stage  130 - 1  at the resonance frequency determined by the two first suspensions  120 - 1  and the first stage  130 - 1 . As a result, the first stage  130 - 1  is resonated at the resonance frequency determined by the two first suspensions  120 - 1  and the first stage  130 - 1 . 
     On the other hand, to each of the two coils  151 - 2 , a desired voltage is applied in desired timing from the actuator drive circuit  22 . By this, a force caused by the electromagnetic force is applied to the second stage  130 - 2  as the excitation force. As a result, the second stage  130 - 2  is driven (i.e. is displaced) in the X-axis direction, by using the elasticity of the second suspensions  120 - 2 . 
     At this time, the actuator drive circuit  22  applies the desired voltage to each of the two coils  151 - 2  in the desired timing so as to apply the driving force for displacing the second stage  130 - 2  in the stepwise manner or in the continuous manner by a predetermined amount. More specifically, the actuator drive circuit  22  applies the desired voltage to each of the two coils  151 - 2  in the desired timing such that the driving force for realizing a tracking operation on the recording surface of the recording medium  30  by the displacement of the second stage  130 - 2  is applied. As a result, the second stage  130 - 2  is displaced in the stepwise manner or in the continuous manner by the predetermined amount. 
     As described above, in the driving apparatus  100   q  in the sixth example, the second stage  130 - 2  can be displaced in the X-axis direction while resonating it in the Y-axis direction, as in the aforementioned driving apparatus  100   l  in the fifth example, by resonating the first stage  130 - 1  in the Y-axis direction and by displacing the second stage  130 - 2  disposed on the first stage  130 - 1  in the X-axis direction. In other words, it is possible to biaxially drive the second stage  130 - 2  (i.e. the plurality of probes  12  disposed on the second stage  130 - 2 ). Thus, it is possible to record the data onto the substantially entire recording surface on the recording medium  30  having a rectangular shape, or to reproduce the data recorded on the substantially entire recording surface on the recording medium  30 , by using the plurality of probes  12 . 
     Moreover, even in the driving apparatus  100   q  in the sixth example, the second stage  130 - 2  is displaced in the Y-axis direction by using the resonance as in the aforementioned driving apparatus  100   a  in the first example or the like, so that it is possible to receive the same effects as those received by the driving apparatus  100   a  in the first example. In other words, it is possible to reduce the electric energy which is necessary to apply the excitation force necessary for the displacement of the second stage  130 - 2  to the first stage  130 - 1 . Therefore, it is possible to displace the second stage  130 - 2  more efficiently, resulting in the lower power consumption of the driving apparatus  100   q . Moreover, since the behavior of the oscillation system including the first stage  130 - 1  provided with the second stage  130 - 2  and the two first suspensions  120 - 1 , which is the resonance, is used to displace the first stage  130 - 1 , it is possible to preferably maintain the stability of the position of the first stage  130 - 1  (i.e. the second stage  130 - 2  disposed on the first stage  130 - 1 ). As a result, it is possible to preferably obtain the repeatability with respect to aspects of the displacement of the second stage  130 - 2 . As a result, it is possible to record the data at a desired position on the recording medium  30 , or to reproduce the data recorded at the desired position on the recording medium  30 . 
     Incidentally, in the driving apparatus  100   q  in the sixth example, if the first base  110 - 1 , one of the first suspensions  120 - 1 , and the first stage  130 - 1  are regarded as one driving apparatus, it is possible to read, from the explanations and corresponding drawings described above, that the one driving apparatus including the first base  110 - 1 , the one first suspension  120 - 1 , and the first stage  130 - 1  has substantially the same structure as the aforementioned driving apparatus adopting the uniaxial driving method (in particular, the driving apparatus  100   i  in the third example). Moreover, if the first stage  130 - 1 , one of the second suspensions  120 - 2 , and the second stage  130 - 2  are regarded as one driving apparatus, it is possible to read, from the explanations and corresponding drawings described above, that the driving apparatus including the first stage  130 - 1 , the one second suspension  120 - 2 , and the second stage  130 - 2  has substantially the same structure as the aforementioned driving apparatus adopting the uniaxial driving method (in particular, the driving apparatus  100   i  in the third example). In other words, the first stage  130 - 1  functions as the aforementioned stage  130  in the driving system including the first stage  130 - 1 , the first suspension  120 - 1 , and the first stage  130 - 1 , whereas the first stage  130 - 1  functions as the aforementioned base  110  in the driving system including the first stage  130 - 1 , the second suspension  120 - 2 , and ht second stage  130 - 2 . 
     However, the second base  110 - 2  may be disposed on the first stage  130 - 1 , and the second suspensions  120 - 2  and the second stage  130 - 2  may be disposed on the second base  110 - 2 . Even in such construction, obviously, it is possible to preferably receive the aforementioned various effects. 
     In addition, in the driving apparatus  100   q , the coils  151 - 1  and the magnetic poles  152 - 1  which are the driving sources for displacing the first stage  130 - 1  are disposed at symmetrical positions on the left and right sides of the first stage  130 - 1 . By this, it is possible to control the position of the first stage  130 - 1  by using the two pairs of coils  151 - 1  and magnetic poles  152 - 1 . By adjusting the voltage (e.g. its magnitude, phase, or the like) applied to each of the two pairs of coils  151 - 1  and magnetic poles  152 - 1 , it is possible to preferably prevent a disadvantage of inclination or rotation of the first stage  130 - 1 . 
     Moreover, the driving apparatus  100   q  uses the electromagnetic force by the electromagnetic interaction between ones of the coils  151 - 2  and the magnetic poles  152 - 2  that are fixed to the second stage  130 - 2  and the others of the coils  151 - 2  and the magnetic poles  152 - 2  that are fixed to the first stage  130 - 1 , as the excitation force. In other words, the excitation force is applied to the second stage  130 - 2  as a relative force from the resonating first stage  130 - 1  (i.e. the first stage  130 - 1  as a self-resonator). Thus, the second stage  130 - 2 , and the coils  151 - 2  and the magnetic poles  152 - 2  which are the driving sources for displacing the second stage  130 - 2  are disposed on the common first stage  130 - 1 . By this, even if the first stage  130 - 1  is resonated, the second stage  130 - 2 , and the coils  151 - 2  and the magnetic poles  152 - 2  which are the driving sources for displacing the second stage  130 - 2  are displaced in substantially the same aspect. Therefore, the driving apparatus  100   q  can be constructed without considering an influence of the bias in the Y-axis direction caused by the resonance of the first stage  130 - 1 . By this, it is possible to simplify the structures of the second stage  130 - 2 , and the coils  151 - 2  and the magnetic poles  152 - 2  which are the driving sources for displacing the second stage  130 - 2 . Specifically, it is possible to miniaturize the magnetic pole  152 - 2 . 
     Incidentally, instead of the structure for applying the excitation force caused by the electromagnetic force to the second stage  130 - 2 , even if the structure for applying the excitation force caused by the electrostatic force to the second stage  130 - 2  is adopted, it is possible to preferably form the plurality of comblike electrodes explained by using  FIG. 10  and the like by applying the excitation force as the relative force from the first stage  130 - 1  to the second stage  130 - 2 . Moreover, instead of the structure for applying the excitation force caused by the electromagnetic force to the second stage  130 - 2 , even if the structure for applying the excitation force caused by the piezoelectric effect to the second stage  130 - 2  is adopted, it is possible to preferably form the electrode  141 , the piezoelectric element  142 , and the electrode  143  by applying the excitation force as the relative force from the first stage  130 - 1  to the second stage  130 - 2 . 
     However, in addition to or instead of applying the excitation force as the relative force from the first stage  130 - 1  to the second stage  130 - 2 , the excitation force as the relative force from the first base  110 - 1  may be applied to the second stage  130 - 2 . This structure will be explained with reference to  FIG. 26 .  FIG. 26  is a plan view conceptually showing another structure of the driving apparatus  100   r  in the sixth example. 
     As shown in  FIG. 26 , the driving apparatus  100   r  has substantially the same structure as the aforementioned driving apparatus  100   q . In the driving apparatus  100   r , in particular, the others of the coils  151 - 2  and the magnetic poles  152 - 2  that are not fixed to the second stage  130 - 2  (the coils  151 - 2  in  FIG. 26 ) are fixed to the first base  110 - 1 , instead of the first stage  130 - 1 . Therefore, the driving apparatus  100   r  uses the electromagnetic force by the electromagnetic interaction between ones of the coils  151 - 2  and the magnetic poles  152 - 2  that are fixed to the second stage  130 - 2  and the others of the coils  151 - 2  and the magnetic poles  152 - 2  that are fixed to the first base  110 - 1 , as the excitation force. In other words, the excitation force is applied to the second stage  130 - 2  as the relative force from the fixed first base  110 - 1 . 
     In the driving apparatus  100   r  having the aforementioned structure, if the first stage  130 - 1  is resonated, the location of the second stage  130 - 2  varies with respect to the other of the coils  151 - 2  and the magnetic poles  152 - 2  which are the driving sources for displacing the second stage  130 - 2 . Therefore, in the driving apparatus  100   r , since there is no more influence of the unexpected bias in the X-axis direction, if the displacement of the plurality of probes  12  is focused on, the accuracy of the displacement increases. 
     Incidentally, the aforementioned driving apparatus  100   q  in the sixth example is provided with one second stage  130 - 2  on the first stage  130 - 1 ; however, it may be provided with a plurality of second stages  130 - 2  on the first stage  130 - 1 . In other words, the second stage  130 - 2  shown in  FIG. 25  may be divided. This structure will be explained with reference to  FIG. 27 .  FIG. 27  is a plan view conceptually showing the structure of a driving apparatus  100   s  provided with the plurality of second stages  130 - 2  on the first stage  130 - 1 . 
     As shown in  FIG. 27 , the driving apparatus  100   s  is provided with the first base  110 - 1 , the two first suspensions  120 - 1 , the coils  151 - 1 , and the magnetic poles  152 - 1 , as in the aforementioned driving apparatus  100   q . Particularly, the driving apparatus  100   s  is provided with the two second stages  130 - 2  each of which has a relatively small size (specifically, each of which has a smaller size than the second stage  130 - 2  in the driving apparatus  100   q ). The two second stages  130 - 2  are arranged in line in the X-axis direction (in other words, the displacement direction by the tracking operation). In other words, the two second stages  130 - 2  in the driving apparatus  100   s  are obtained by dividing the second stage  130 - 2  in the driving apparatus  100   q  along a direction substantially perpendicular to the X-axis. To each of the two second stages  130 - 2 , the other edge of the corresponding second suspension  120 - 2  is connected. Each of the two second suspensions  120 - 2  is connected to the first stage  130 - 1  at its one edge. Moreover, the driving apparatus  100   s  is provided with the two pairs of coils  151 - 2  and magnetic poles  152 - 2 , each pair of which are the driving sources for displacing one second stage  130 - 2 , for each second stage  130 - 2  independently. 
     In the driving apparatus  100   s , the actuator drive circuit  22  applies a desired voltage to each coil  151 - 2  in desired timing so as to apply the excitation force for displacing each of the second stages  130 - 2 . As a result, each of the two second stages  130 - 2  oscillates (i.e. is displaced) in the X-axis direction. 
     By this, even in the driving apparatus  100   s , it is possible to receive the same effects as those received by the driving apparatus  100   o  described above. 
     Moreover, since the size of each of the second stages  130 - 2  can be reduced, it is possible to relatively reduce the mass of each of the second stages  130 - 2 . Thus, even if the size of the second suspension  120 - 2  for supporting each of the second stages  130 - 2  is reduced (e.g. even if its thickness or its width is reduced), it is possible to preferably support each of the second stages  130 - 2 . Therefore, it is possible to lighten or miniaturize the driving apparatus  100   s.    
     In addition, in the driving apparatus  100   s , the plurality of second stages  130 - 2  are arranged to be in line in the displacement direction by the tracking operation. Here, in the recording medium  30  having a rectangular shape, there may be variations between thermal expansion in one area on the recording surface of the recording medium  30  and thermal expansion in another area distant from the one area. Thus, there may be such a disadvantage that the pitch of data in the one area does not match the pitch of data in the other area. Here, if using a driving apparatus provided with a single second stage  130 - 2 , the tracking operation is performed on all the probes  12  by a common distance. Therefore, the probes  12  provided in vicinity of one edge of the second stage  130 - 2  can perform data recording and reproduction in a desired area portion (e.g. an area portion to record the data, an area portion to reproduce the data) in the one area on the recording surface of the recording medium  30 , whereas the probes  12  provided in vicinity of the other edge of the second stage  130 - 2  cannot perform the data recording and reproduction in a desired area portion in the other area on the recording surfaced of the recording medium  30 , which may be disadvantageous. According to the driving apparatus  100   s , however, the two second stages  130 - 2  are provided, and each of the two second stages  130 - 2  is displaced by the corresponding driving source of the two independent driving sources. Therefore, even if there are variations between the thermal expansion in the one area on the recording surface of the recording medium  30  and the thermal expansion in the other area, the displacement of the probes  12  in each of the one area and the other area can be independently performed, so that it is possible to preferably perform the data recording operation and reproduction operation with respect to each of the one area and the other area. 
     Incidentally, with respect to the aforementioned driving apparatus  100   q  in the sixth example (and moreover, the driving apparatus  100   r  to the driving apparatus  100   s ), obviously, the various structures explained in the first example to the fifth example described above may be applied, as occasion demands. 
     (2-2-3) Seventh Example 
     Next, with reference to  FIG. 28  and  FIG. 29 , a driving apparatus  100   t  in a seventh example will be explained.  FIG. 28  is a plan view conceptually showing the structure of the driving apparatus  100   t  in the seventh example.  FIG. 29  is a plan view conceptually showing an aspect when the stage of the driving apparatus  100   t  in the seven example shown in  FIG. 28  is displaced. 
     As shown in  FIG. 28 , the driving apparatus  100   t  in the seventh example is provided with the stage  130  provided with the plurality of probes  12 . On each of the left and right sides of the stage  130 , there are provided the two first suspensions  120 - 1  each of which extends in a longitudinal direction and each of which is fixed to the stage  130  at its one edge. Incidentally, in the explanation below, for simplification of explanation, the structure of the right side of the stage  130  will be described; however, the left side of the stage  130  obviously has the same structure. 
     The two first suspensions  120 - 1  are arranged to match the longitudinal direction and the X-axis direction and to be adjacent in a lateral direction (i.e. Y-axis direction). The other edges of the two first suspensions  120 - 1  are fixed to one edges of two driving sources  180 . The driving sources  180  are arranged in the Y-axis direction and each of them is provided with an excitation force application device  181  for applying the excitation force to displace the stage  130  in the Y-axis direction; and a driving force application device  182  for applying the driving force to displace the stage  130  in the X-axis direction. To the other edges of the driving sources  180 , the two second suspensions  120 - 2  are fixed which extend in the longitudinal direction. The two second suspension  120 - 2  are arranged to match the longitudinal direction and the X-axis direction and to be adjacent in the lateral direction (i.e. Y-axis direction). The other edges of the two second suspensions  120 - 2  are fixed to one edge of a third suspension  120 - 3  which can extend and contract in the X-axis direction. The other edge of the third suspension  120 - 3  is fixed to the base  110 . Moreover, the stage  130  is connected to a tracking circuit  190  for performing the tracking operation of the stage  130  in the X-axis direction in a narrower range than the tracking operation by the driving force application device  182 . 
     Incidentally, the stage  130 , the two first suspension  120 - 1 , the two driving sources  180 , the two second suspensions  120 - 2 , the third suspension  120 - 3 , and the base  110  are arranged in line in the X-axis direction. 
     The stage  130  is displaced in the Y-axis direction, as shown in  FIG. 29 , by using the elasticity of the two first suspensions  120 - 1  and the two second suspensions  120 - 2 . In this case, the two first suspensions  120 - 1  actually oscillate, whereas the two second suspensions  120 - 2  do not oscillate or rarely oscillate. Thus, the second suspensions  120 - 2  may be omitted so that the driving sources  180  and the third suspension  120 - 3  are connected. Alternatively, the second suspensions  120 - 2  and the third suspension  120 - 3  may be unified. 
     Moreover, the stage  130  is displaced in the X-axis direction, as shown in  FIG. 29 , by using the elasticity of the third suspension  120 - 3 . The excitation force and the driving force for displacing the stage  130  as described above are applied by applying a desired voltage in desired timing from the actuator drive circuit  22  to the excitation force application device  181  and the driving force application device  182  provided for the driving source  180 . Incidentally, the excitation force application device  181  and the driving force application device  182  may have the structure for applying the driving force and the excitation force caused by the piezoelectric element (specifically, the electrode  141 , the piezoelectric element  142 , and the electrode  143 ), or the structure for applying the driving force and the excitation force caused by the electromagnetic force (specifically, the coil  151  and the magnetic pole  152 ), or the structure for applying the driving force and the excitation force caused by the electrostatic force (specifically, the electrode  161  and the electrode  162 ). 
     Moreover, the actuator drive circuit  22  applies the desired voltage in the desired timing to the excitation force application device  181  so as to apply the excitation force for oscillating (i.e. resonating) the stage  130  at the resonance frequency determined by the stage  130  and the two first suspensions  120 - 1  on each side, i.e. four in total. As a result, the stage  130  is resonated at the resonance frequency determined by the stage  130  and the two first suspensions  120 - 1  on each side, i.e. four in total. 
     On the other hand, the actuator drive circuit  22  applies the desired voltage in the desired timing to the driving force application device  182  so as to apply the driving force for displacing the stage  130  in the stepwise manner or in the continuous manner by a predetermined amount. As a result, the stage  130  is displaced in the X-axis direction in the stepwise manner or in the continuous manner by the predetermined amount. 
     In addition, the tracking circuit  190  displaces the stage  130  in the stepwise manner or in the continuous manner by a predetermined amount and by a finer unit than the tracking operation by the driving force application device  182 . As a result, the tracking operation is highly accurately performed on the stage  130  in the X-axis direction. 
     Thus, the driving apparatus  100   t  in the seventh example can resonate the stage  130  in the Y-axis direction and displace the stage  130  in the X-axis direction. In other words, it is possible to biaxially drive the stage  130  (i.e. the plurality of probes  12  disposed on the stage  130 ). Thus, it is possible to record the data onto the substantially entire recording surface on the recording medium  30  having a rectangular shape, or to reproduce the data recorded on the substantially entire recording surface on the recording medium  30 , by using the plurality of probes  12 . 
     Moreover, even in the driving apparatus  100   t  in the seventh example, since the stage  130  is displaced in the Y-axis direction by using the resonance as in the aforementioned driving apparatus  100   a  in the first example or the like, it is possible to receive the same effects as those received by the driving apparatus  100   a  in the first example. In other words, it is possible to reduce the electric energy which is necessary to apply the excitation force necessary for the displacement of the stage  130 . Therefore, it is possible to displace the stage  130  more efficiently, resulting in the lower power consumption of the driving apparatus  100   t . Moreover, since the behavior of the oscillation system including the stage  130  and the two suspensions  120 - 1 , which is the resonance, is used to displace the stage  130 , it is possible to preferably maintain the stability of the position of the stage  130 . As a result, it is possible to preferably obtain the repeatability with respect to aspects of the displacement of the stage  130 . As a result, it is possible to record the data at a desired position on the recording medium  30 , or to reproduce the data recorded at the desired position on the recording medium  30 . 
     Incidentally, in the driving apparatus  100   t  in the seventh example, the phase (or direction) of the excitation force applied by the upper driving source  180  of the two driving sources  180  arranged in the Y-axis direction may be shifted from the phase (or direction) of the excitation force applied by the lower driving source  180  of the two driving sources  180  arranged in the Y-axis direction. By shifting the phases of the excitation forces applied by the two driving sources  180  arranged in the Y-axis direction (i.e. the direction of the resonance) as described above, the amplitude of the resonance of the stage  130  (i.e. the displacement range in the Y-axis direction of the stage  130 ) can be adjusted. For example, if the upper driving source  180  applies the excitation force for displacing the stage  130  to the upper side, and if the lower driving source  180  applies the excitation force for displacing the stage  130  to the lower side (i.e. on the opposite side of the direction in which the excitation force applied by the upper driving source  180  displaces the stage  130 ), it is possible to attenuate the amplitude of the resonance of the stage  130 . In the same manner, if the upper driving source  180  applies the excitation force for displacing the stage  130  to the upper side, and if the lower driving source  180  applies the excitation force for displacing the stage  130  to the lower side (i.e. on the same side as the direction in which the excitation force applied by the upper driving source  180  displaces the stage  130 ), it is possible to amplify the amplitude of the resonance of the stage  130 . 
     The aforementioned examples shows that the phases of the two driving sources are shifted by 180 degrees; however, the phases may be shifted not only by 180 degrees but also by 45 degrees, by 90 degrees, by other numeral values, or the phases may be changed continuously. In this case, slight amplitude adjustment is possible. 
     Incidentally, with respect to the aforementioned driving apparatus  100   t  in the seventh example, obviously, the various structures explained in the first example to the sixth example described above may be applied, as occasion demands. 
     (2-2-4) Eighth Example 
     Next, with reference to  FIG. 30 , a driving apparatus  100   u  in an eighth example will be explained.  FIG. 30  is a plan view conceptually showing trajectories of the displacement of the plurality of probes  12  realized by the driving apparatus  100   u  in the eighth example. 
     The driving apparatus  100   l  in the fifth example (and moreover, the driving apparatus  100   m  to the driving apparatus  100   p ), the driving apparatus  100   q  in the sixth example (and moreover, the driving apparatus  100   r  and the driving apparatus  100   s ), and the driving apparatus  100   t  in the seventh example described above operate so as to realize such a state that the second stage  130 - 2  is resonated only in the Y-axis direction. In other words, the second stage  130 - 2  is not resonated in the X-axis direction. The driving apparatus  100   u  in the eighth example, however, operates so as to realize such a state that the second stage  130 - 2  is resonated in each of the Y-axis direction and the X-axis direction, while having the same structure as those of the driving apparatus  100   l  in the fifth example (and moreover, the driving apparatus  100   m  to the driving apparatus  100   p ), the driving apparatus  100   q  in the sixth example (and moreover, the driving apparatus  100   r  and the driving apparatus  100   s ), and the driving apparatus  100   t  in the seventh example described above. 
     At this time, in the driving apparatus  100   u  in the eighth example, the phase of the resonance in the X-axis direction of the second stage  130 - 2  and the phase of the resonance in the Y-axis direction of the second stage  130 - 2  are shifted by approximately 90 degrees. In other words, a desired voltage is applied in desired timing from the actuator drive circuit  22  so as to apply the excitation force by which the phase of the resonance of the second stage  130 - 2  in the X-axis direction and the phase of the resonance of the second stage  130 - 2  in the Y-axis direction can be shifted by approximately 90 degrees. As a result, the trajectories of the plurality of probes  12  are circular orbits as shown in  FIG. 30 . 
     In this case, the radius of the circular orbit may be changed depending on the number of the probes  12  disposed on the second stage  130 - 2 . For example, if the number of the probes  12  is relatively small, it is preferable to increase the radius of the circular orbit because the area portion in which the data recording and reproduction are performed by one probe  12  becomes relatively large. On the other hand, if the number of the probes  12  is relatively large, it is preferable to reduce the radius of the circular orbit due to the area portion in which the data recording and reproduction are performed by one probe  12  becomes relatively small. 
     Even in such a driving apparatus  100   u , it is possible to properly receive the aforementioned various effects. 
     Incidentally, with respect to the aforementioned driving apparatus  100   u  in the eighth example, obviously, the various structures explained in the first example to the seventh example described above may be applied, as occasion demands. 
     Incidentally, the aforementioned explanation describes the example that the plurality of probes  12  are disposed on the stage  130  of the driving apparatus  100 ; however, instead of the plurality of probes  12 , the recording medium  30  may be disposed on the stage  130  of the driving apparatus  100 . 
     Moreover, the aforementioned explanation describes the example that the driving apparatus  100  is applied to the ferroelectric recording/reproducing apparatus  1 ; however, obviously, the driving apparatus  100  may be applied not only to the ferroelectric recording/reproducing apparatus  1  but also to various information recording/reproducing apparatuses including various probe memories. Moreover, the driving apparatus  100  may be applied not only to the information recording/reproducing apparatuses but also to a structure using the probe (e.g. AFM (Atomic Force Microscopy)). Moreover, the driving apparatus  100  may be applied to various apparatuses for displacing the stage in the two axes: the X-axis and the Y-axis. 
     Moreover, in the present invention, various changes may be made, if desired, without departing from the essence or spirit of the invention which can be read from the claims and the entire specification. A driving apparatus which involves such changes is also intended to be within the technical scope of the present invention. 
     INDUSTRIAL APPLICABILITY 
     The driving apparatus of the present invention can be applied to a driving apparatus for driving a medium or the like in a uniaxial direction or biaxial directions so that the probe scans the surface or the like of the medium.