Abstract:
Disclosed herein is an exciting method for an elastic vibration member which may include arranging two support members each formed from an electromechanical energy transducer; supporting the elastic vibration member to the two support members at their front ends; and supplying drive signals having the same frequency and a phase difference to the two support members, circularly or elliptically vibrating the elastic vibration member.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority from Japanese Patent Application No. JP 2006-002111 filed in the Japanese Patent Office on Jan. 10, 2006, the entire content of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an exciting method for an elastic vibration member and a vibratory driving device.  
         [0004]     2. Description of the Related Art  
         [0005]     In the past proposed is an exciting method for an elastic vibration member in a vibratory driving device for linear or rotational motion.  
         [0006]     For example, a first technique in the related art mentioned below is proposed. This technique includes an elastic vibration member, a drive member having at least two electrodes and an electromechanical energy transducer for exciting the elastic vibration member by applying drive voltages having the same frequency and two phases to these two electrodes, and a driven member kept in contact with the elastic vibration member. The drive member forms a first bending vibration mode by the input of the drive voltages having the same phase, and also forms a second bending vibration mode by the input of the drive voltages having opposite phases. By the combination of these two bending vibration modes, a circular or elliptical motion is produced in the elastic vibration member (see Japanese Patent Laid-open No. 2004-320846 referred to as Patent Document 1).  
         [0007]     A second technique in the related art mentioned below is also proposed. This technique includes a square bar-shaped elastic base, a plurality of drive elements projecting from one side surface of the base at given positions, and an elastic vibration member connected to the base. By applying an alternating voltage to the base, bending resonance and longitudinal resonance are simultaneously produced in the base. By the combination of these bending and longitudinal vibration modes, a circular or elliptical motion is produced in the elastic vibration member (see Japanese Patent Publication No. 6-106028 referred to as Patent Document 2).  
         [0008]     However, according to Patent Document 1, two bending vibration modes are combined so as to excite the elastic vibration member in a circular or elliptical motion.  
         [0009]     Usually, the resonant frequencies in the two bending vibration modes are not equal to each other. Further, it is not ensured that the frequency ranges of these two bending vibration modes are adjacent to each other. To make the resonant frequencies in the two bending vibration modes equal to each other, adjustment (degeneration) of the size, shape, thickness, etc. of the elastic vibration member may be required, causing a limitation to the shape of the elastic vibration member and a difficulty of design.  
         [0010]     In Patent Document 2, the bending vibration mode and the longitudinal vibration mode are combined. Accordingly, the use of the longitudinal vibration mode (vertical vibration) generally causes an increase in resonant frequency, which is impractical. Further, when the longitudinal size of the elastic vibration member is reduced, a further increase in resonant frequency is undesirably invited.  
         [0011]     Moreover, both in Patent Document 1 and 2, a circular or elliptical motion as a driving force can be produced by combining the two vibration modes, or exciting the two vibration modes. Accordingly, precise control of the driving frequency and a limitation to the driving frequency are necessary. Further, a limitation to the shape and size of the elastic vibration member and a dimensional accuracy in working the elastic vibration member are necessary for the excitation of the two vibration modes at near frequencies, causing an increase in cost.  
       SUMMARY OF THE INVENTION  
       [0012]     The present invention provides a vibratory driving device which can be designed easily and flexibly at a low cost.  
         [0013]     In accordance with a first embodiment of the present invention, there is provided an exciting method for an elastic vibration member including the steps of arranging two support members each formed from an electromechanical energy transducer; supporting the elastic vibration member to the two support members at their front ends; and supplying drive signals having the same frequency and a phase difference to the two support members, thereby circularly or elliptically vibrating the elastic vibration member.  
         [0014]     In accordance with a second embodiment of the present invention, there is provided a vibratory driving device including a base; two support members supported to the base, each of the two support members being formed from an electromechanical energy transducer; an elastic vibration member supported to the two support members at their front ends; and control means for inputting drive signals having the same frequency and a phase difference to the two support members.  
         [0015]     In accordance with a third embodiment of the present invention, there is provided a vibratory driving device including a base; two support members supported to the base and extending in parallel to each other, each of the two support members being formed from an electro-mechanical energy transducer; an elastic vibration member supported to the two support members at their front ends; and control means for inputting drive signals having the same frequency and a phase difference to the two support members; the elastic vibration member being formed with a projecting portion at a position between the front ends of the two support members, the projecting portion projecting on one side of the elastic vibration member opposite to the other side where the two support members are arranged; a driven member being supported in opposed relationship to the projecting portion so as to be movable in a plane perpendicular to the longitudinal direction of the two support members; the vibratory driving device further including pressure applying means for bringing the driven member into, pressure contact with the Projecting portion.  
         [0016]     In accordance with a fourth embodiment of the present invention, there is provided a vibratory driving device movably supported between a driven member and a pressure rail extending in parallel to each other, including a base kept in slidable contact with the pressure rail; two support members supported to the base and extending in parallel to each other in a direction perpendicular to the longitudinal direction of the driven member and the pressure rail and being formed from an electromechanical energy transducer; an elastic vibration member supported to the two support members at their front ends; and control means for inputting drive signals having the same frequency and a phase difference to the two support members; the elastic vibration member being formed with a projecting portion at a position between the front ends of the two support members, the projecting portion projecting toward the driven member; the vibratory driving device further including pressure applying means for bringing the driven member into pressure contact with the projecting portion.  
         [0017]     According to an embodiment of the present invention, the drive signals having the same frequency and a phase difference are respectively supplied to the two support members to thereby excite the elastic vibration member, so that the elastic vibration member can be reliably vibrated circularly or elliptically.  
         [0018]     Accordingly, it is necessary to combine two vibration modes, but a stretch mode as a single vibration mode is used in the present invention, so that the vibratory driving device can be designed easily and flexibly, and it is possible to ensure the flexibility of choice of the shape, size, and material of the elastic vibration member.  
         [0019]     Further, since the shape and size of the elastic vibration member are less limited, a cost reduction can be expected.  
         [0020]     Further, since the projecting portion and the driven member are kept in pressure contact with each other by the pressure applying means, the motion of the driven member due to the circular or elliptical vibration of the projecting portion can be reliably produced. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is a perspective view of a vibratory driving device according to a first preferred embodiment of the present invention;  
         [0022]      FIG. 2  is a schematic diagram illustrating first and second drive signals;  
         [0023]      FIGS. 3 and 4  are schematic diagrams illustrating the loci of elliptical motions of a projecting portion under different conditions;  
         [0024]      FIG. 5  is a partially sectional elevation of a vibratory driving device according to a second preferred embodiment of the present invention;  
         [0025]      FIG. 6  is a perspective view of a vibratory driving device according to a third preferred embodiment of the present invention;  
         [0026]      FIG. 7  is a perspective view of a vibratory driving device according to a fourth preferred embodiment of the present invention;  
         [0027]      FIG. 8  is an elevational view of a vibratory driving device according to a fifth preferred embodiment of the present invention;  
         [0028]      FIG. 9  is a perspective view showing a lens moving mechanism including a vibratory driving device according to a sixth preferred embodiment of the present invention;  
         [0029]      FIG. 10  is an enlarged perspective view of an essential part shown in  FIG. 9 ;  
         [0030]      FIG. 11  is a perspective view showing a lens moving mechanism including a vibratory driving device according to a seventh preferred embodiment of the present invention;  
         [0031]      FIG. 12  is an elevational view showing a shake correcting mechanism including a vibratory driving device according to an eighth preferred embodiment of the present invention; and  
         [0032]      FIG. 13  is a perspective view showing a diaphragm mechanism including a vibratory driving device according to a ninth preferred embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     First Preferred Embodiment  
       [0033]     Preferred embodiments of the present invention will now be described with reference to the attached drawings.  
         [0034]      FIG. 1  is a perspective view of a vibratory driving device  10  according to the first preferred embodiment.  
         [0035]     As shown in  FIG. 1 , the vibratory driving device  10  includes a base  12 , two support members  14 , an elastic vibration member  16 , and a drive circuit  18  (corresponding to the control section in the present invention).  
         [0036]     The base  12  is an elongated rectangular plate member and has an upper surface having an area enough to mount the lower ends of the two support members  14 .  
         [0037]     The base  12  is formed of a metal material such as brass.  
         [0038]     Each of the two support members  14  is a columnar member having a rectangular cross section and a height larger than the length of each side of the rectangular cross section. The sectional shape of each support member  14  is not limited to such a rectangular shape as in this preferred embodiment, but any other shapes such as a circular shape may be adopted in the present invention. Further, it is not necessary to set the height of each support member  14  larger than the length of each side of the rectangular cross section. However, it is advantageous that the columnar shape having such a larger height as in this preferred embodiment can increase the amplitude of vibration.  
         [0039]     The lower ends of the two support members  14  are fixed by an adhesive to the upper surface of the base  12  at its longitudinal opposite ends. The two support members  14  extend in parallel to each other in a direction perpendicular to the upper surface of the base  12 .  
         [0040]     Each support member  14  is formed from an electro-mechanical energy transducer expanding and contracting along the height according to an input drive signal. For example, a stacked piezoelectric element may be used as the electro-mechanical energy transducer.  
         [0041]     In this preferred embodiment, the two support members  14  have the same shape and size, and each support member  14  has a size of 1.65° mm for each side of the rectangular cross section and a height of 5 mm.  
         [0042]     For the convenience of illustration, one of the two support members  14  will be referred to as a first support member  14 A and the other will be referred to as a second support member  14 B.  
         [0043]     The elastic vibration member  16  has a body plate portion  20  and a projecting portion  22 .  
         [0044]     The body plate portion  20  is an elongated plate member having a thickness, a width larger than the thickness, and a length larger than the width.  
         [0045]     The body plate portion  20  is composed of a first thick-walled portion, a first thin-walled portion, a second thick-walled portion, a second thin-walled portion, and a third thick-walled portion arranged in this order in the longitudinal direction of the body plate portion  20 .  
         [0046]     More specifically, the lower surface of the body plate portion  20  is formed with two recesses  23  on the longitudinally opposite sides of a longitudinally central portion of the body plate portion  20 , thereby forming two thin-walled portions  24  (the first and second thin-walled portions mentioned above) respectively corresponding to the two recesses  23 . Each thin-walled portion  24  is lower in rigidity than the other portion of the body plate portion  20 .  
         [0047]     Further, as the result of the formation of the two recesses  23 , two first projections  26  (the first and third thick-walled portions mentioned above) are formed on the lower surface of the body plate portion  20  at the longitudinally opposite ends.  
         [0048]     Further, a second projection  28  (the second thick-walled portion mentioned above) higher than each first projection  26  is formed on the lower surface of the body plate portion  20  at the longitudinally central position between the two recesses  23 .  
         [0049]     The projecting portion  22  projects from the upper surface of the body plate portion  20  at the longitudinally central position.  
         [0050]     The projecting portion  22  has an upper end  22 A adapted to abut against a driven member to be moved by vibration of the projecting portion  22 .  
         [0051]     In this preferred embodiment, the projecting portion  22  has the same sectional shape as that of the second projection  28  and is aligned to the second projection  28 .  
         [0052]     The elastic vibration member  16  is mounted on the two support members  14  in the following manner.  
         [0053]     The second projection  28  is inserted between the upper end portions of the two support members  14 , so that the opposite side surfaces of the second projection  28  abut against the opposed side surfaces of the upper end portions of the two support members  14 , thereby positioning the elastic vibration member  16  with respect to the two support members  14  in the longitudinal direction of the base  12 .  
         [0054]     The lower surfaces of the first-projections  26  are bonded by an adhesive to the upper end surfaces of the two support members  14 .  
         [0055]     In this preferred embodiment, the elastic vibration member  16  is formed of brass. Further, the body plate portion  20  has a width of 1.7 mm and a length of 4.8 mm. The height from the lower surface of the second projection  28  to the upper end  22 A of the projecting portion  22  is set to 2 mm.  
         [0056]     The drive circuit  18  functions to supply a first drive signal SA and a second drive signal SB to the first support member  14 A and the second support member  14 B, respectively, and constitutes the control section in the present invention.  
         [0057]     In this preferred embodiment, alternating voltages are used as the first and second drive signals SA and SB.  
         [0058]     The operating principles of the vibratory driving device  10  will now be described.  
         [0059]     According to the computer analysis using a finite element method, the elastic vibration member  16  can be excited at a frequency of about 70 to 74 kHz in the case of vibrating the first and second support members  14 A and  14 B in a stretch mode.  
         [0060]     The projecting portion  22  is located in the vicinity of a position where a crest or trough is formed during vibration in the stretch mode. Accordingly, the projecting portion  22  can be displaced at the maximum in the stretching direction.  
         [0061]     When the drive signal SA having a frequency near the resonant frequency in the stretch mode is applied to the first support member  14 A, and the drive signal SB having the same frequency and phase as those of the drive signal SA is applied to the second support member  14 B, the first and second support members  14 A and  14 B are excited simultaneously in the stretch mode.  
         [0062]     In this case, the projecting portion  22  simply vibrates in the vertical direction.  
         [0063]     In the case that the drive signals SA and SB to be applied to the first and second support members  14 A and  14 B have a phase angle (phase difference), the operation of the vibratory driving device  10  is as follows:  
         [0064]      FIG. 2  illustrates the first and second drive signals SA and SB, and  FIGS. 3 and 4  illustrate the loci of elliptical motions of the projecting portion  22  under different conditions.  
         [0065]     As shown in  FIG. 2 , the second drive signal SB having the same frequency and amplitude as those of the first drive signal SA is supplied to the second support member  14 B so that the phase angle between the first and second drive signals SA and SB becomes about π/2 (90 degrees) or about −π/2 (−90 degrees) by the drive circuit  18 . In this case, the projecting portion  22  of the elastic vibration member  16  is circularly or elliptically vibrated by the stretch displacement (expansion and contraction) of the first and second support members  14 A and  14 B as shown in  FIG. 3 .  
         [0066]      FIG. 3  shows the case that the frequency of the drive signals SA and SB is different from the resonant frequency in the stretch mode. In this case, the projecting portion  22  is elliptically vibrated so as to describe a flattened ellipse having a major axis perpendicular to the vertical direction (Z direction) and parallel to the horizontal direction (X direction) along which the first and second support members  14 A and  14 B are arranged.  
         [0067]     In this case, the vibrational component in the vertical direction (Z direction) along which the projecting portion  22  pushes the driven member is insufficient, so that a driving force may not be ensured.  
         [0068]     To cope with this problem, the frequency of the drive signals SA and SB to be applied to the first and second support members  14 A and  14 B is set substantially equal to the resonant frequency in the stretch mode. As a result, the stretch mode is excited in the elastic vibration member  16 , so that the vibrational moment in the vertical direction (z direction) is increased as shown in  FIG. 4 , thereby producing a stable driving force.  
         [0069]     Further, by setting the phase angle of the drive signal SB to be applied to the second support member  14 B to about π/2 or about −π/2, the rotational direction of the circular or elliptical vibration can be set clockwise for the phase angle of about π/2 or anticlockwise for the phase angle of about −π/2.  
         [0070]     Further, by bringing the driven member into pressure contact with the projecting portion  22  of the elastic vibration member  16  through any pressure applying section, the moving direction of the driven member can be inverted.  
         [0071]     Accordingly, the driving and inverting operations of the vibratory driving device  10  can be performed by using only one vibration mode (stretch mode).  
         [0072]     The amplitudes of the drive signals SA and SB to be applied to the first and second support members  14 A and  14 B are not necessarily set equal to each other, depending on the use mode of the vibratory driving device  10 .  
         [0073]     The resonant frequency in the stretch mode excited in the support members  14  will now be described.  
         [0074]     In the case that the thickness of each thin-walled portion  24  formed between the projecting portion  22  of the elastic vibration member  16  and each support member  14  is set to 0.3 mm, the resonant frequency in the stretch mode is 71.7 kHz according to the computer analysis.  
         [0075]     When the thickness of each thin-walled portion  24  is changed to 0.2 mm, the resonant frequency in the stretch mode can be reduced to 54.8 kHz according to the computer analysis.  
         [0076]     When the material of the elastic vibration member  16  is changed from brass to stainless steel and the thickness of each thin-walled portion  24  is changed to 0.195 mm, the resonant frequency in the stretch mode can be made substantially equal to 71.7 kHz according to the computer analysis.  
         [0077]     In this manner, the resonant frequency in the stretch mode can be adjusted by changing the shape and/or material of the elastic vibration member  16 .  
         [0078]     The thin-walled portions  24  of the elastic vibration member  16  are not essential. However, the formation of the thin-walled portions  24  in the elastic vibration member  16  can reduce the rigidity at the thin-walled portions  24 , thereby attaining easy excitation of the elastic vibration member  16 .  
         [0079]     According to this preferred embodiment, the elastic vibration member  16  is excited by respectively supplying the drive signals SA and SB to the two support members  14 A and  14 B and thereby vibrating these support members  14 A and  14 B in the stretch mode. Accordingly, circular or elliptical vibration can be reliably produced in the elastic vibration member  16 .  
         [0080]     Accordingly, unlike the related art, it is not necessary to combine two vibration modes, but only the stretch mode as a single vibration mode is used, thereby facilitating the design with ease and ensuring the flexibility of design. Further, the flexibility of choice of the shape, size, and material of the elastic vibration member  16  can be ensured.  
         [0081]     Since only the stretch mode as a single vibration mode is used, the flexibility of setting of the resonant frequency can be ensured. Accordingly, by reducing the resonant frequency, the frequency of the drive signals to be supplied to the support members  14  can be reduced to thereby reduce a power consumption.  
         [0082]     Further, since the shape and size of the elastic vibration member  16  is less limited, a cost reduction can be expected.  
         [0083]     Further, by changing the polarity of the phase difference between the two drive signals to be supplied to the two support members  14  (i.e., by inverting the advance or retard of the phase of the drive signal SB with respect to the drive signal SA), the rotational direction of the circular or elliptical vibration can be inverted in spite of the use of only one vibration mode (stretch mode), so that the flexibility of design can be further ensured.  
       Second Preferred Embodiment  
       [0084]     A second preferred embodiment of the present invention will now be described with reference to  FIG. 5 .  
         [0085]     In the second preferred embodiment, the vibratory driving device  10  is applied to a driven member  30 , thereby constructing a mechanism for linearly reciprocating the driven member  30 .  
         [0086]      FIG. 5  is a partially sectional elevation of the vibratory driving device  10  and its associated parts constituting the above mechanism according to the second preferred embodiment. In  FIG. 5 , substantially the same parts or members as those of the first preferred embodiment are denoted by the same reference numerals.  
         [0087]     As shown in  FIG. 5 , the driven member  30  is a flat elongated plate member supported so as to be reciprocatable in its longitudinal direction.  
         [0088]     A sliding surface member  31  is formed on the upper surface of the driven member  30 . The sliding surface member  31  is formed of a material having a low coefficient of friction, such as a resin material.  
         [0089]     A holding stay  32  is provided in the vicinity of the driven member  30 .  
         [0090]     The holding stay  32  has a bottom wall  3202  located below the driven member  30 , a vertical wall  3204  standing from the bottom wall  3202 , and a top wall  3206  projecting from the vertical wall  3204  and located above the driven member  30 .  
         [0091]     The vibratory driving device  10  shown in  FIG. 5  is held by the holding stay  32  in such a manner that the base  12  is mounted on the upper surface of the bottom wall  3202  and the upper end  22 A of the projecting portion  22  abuts against the lower surface  3002  of the driven member  30  in the condition where the first and second support members  14 A and  14 B extend in a direction perpendicular to the lower surface  3002  of the driven member  30  and are arranged in the longitudinal direction of the driven member  30  (the direction of reciprocating motion of the driven member  30 ).  
         [0092]     A cylindrical external threaded portion  3207  projects from the lower surface of the top wall  3206  at a position directly above the projecting portion  22 , and a through hole  3208  is formed through the top wall  3206  and the external threaded portion  3207 .  
         [0093]     A pressure nut  34  is threadedly engaged with the external threaded portion  3207 .  
         [0094]     A pressure shaft  36  is inserted at its shaft portion  3601  through the through hole  3208 , and a circular plate portion  3602  larger in diameter than the shaft portion  3601  of the pressure shaft  36  is formed at the lower end of the shaft portion  3601 .  
         [0095]     A coil spring  38  is mounted so as to surround the shaft portion  3601  at a position below the pressure nut  34  in such a manner as to be held between the circular plate portion  3602  and the pressure nut  34  under compression.  
         [0096]     The circular plate portion  3602  is biased toward the projecting portion  22  by a biasing force of the coil spring  38 , so that the lower surface of the circular plate portion  3602  as a contact surface  3604  is kept in elastic contact with the sliding surface member  31 , thereby bringing the driven member  30  into pressure contact with the upper end  22 A of the projecting portion  22 .  
         [0097]     By rotating the pressure nut  34 , the biasing force of the coil spring  38  applied to the circular plate portion  3602  can be adjusted to thereby adjust the pressure applied from the driven member  30  to the projecting portion  22 .  
         [0098]     In the second preferred embodiment, the coil spring  38  and the pressure shaft  36  constitute pressure applying section configured to bring the driven member  30  into pressure contact with the projecting portion  22 .  
         [0099]     As in the first preferred embodiment, the drive signals SA and SB are respectively supplied to the support members  14 A and  14 B of the vibratory driving device  10 , thereby circularly or elliptically vibrating the projecting portion  22 , so that the driven member  30  can be linearly reciprocated in the direction shown by the double-headed arrow in  FIG. 5 .  
         [0100]     According to the second preferred embodiment, effects similar to those of the first preferred embodiment can be exhibited. Moreover, the projecting portion  22  and the driven member  30  are kept in pressure contact with each other by the pressure applying section, so that the reciprocating motion of the driven member  30  due to the circular or elliptical vibration of the projecting portion  22  can be reliably produced.  
         [0101]     Even in the condition that the drive signals are not supplied to the support members  14 , the projecting portion  22  and the driven member  30  are kept in pressure contact with each other by the pressure applying section, thereby holding the driven member  30  in position. Accordingly, a power consumption can be reduced.  
         [0102]     Thus, the projecting portion  22  and the driven member  30  are kept in pressure contact with each other by the pressure applying section. Accordingly, the motion of the driven member  30  is started simultaneously with starting of the circular or elliptical vibration of the projecting portion  22 . That is, no backlash is present and the responsiveness of the motion of the driven member  30  can therefore be improved.  
         [0103]     The contact surface  3604  of the pressure shaft  36  is kept in pressure contact with the sliding surface member  31  to press the driven member  30  against the projecting portion  22 . Accordingly, a frictional force between the contact surface  3604  and the driven member  30  can be reduced by the sliding surface member  31 , thereby increasing the efficiency of the motion of the driven member  30 .  
         [0104]     While the coil spring  38  is used as a component of the pressure applying section in the second preferred embodiment, a leaf spring, magnetic spring, and elastic member and the like may be used.  
         [0105]     Further, a lubricant may be applied for the purpose of further reduction in frictional load between the contact surface  3604  and the sliding surface member  31 .  
         [0106]     As a modification, a cross roller guide (linear rolling bearing) or the like may be provided at the lower end of the pressure shaft  36  in place of the sliding surface member  31 , thereby further reducing the frictional resistance due to the pressure applied to the driven member  30 .  
       Third Preferred Embodiment  
       [0107]     A third preferred embodiment of the present invention will now be described with reference to  FIG. 6 .  
         [0108]     The third preferred embodiment is different from the second preferred embodiment in the point that the driven member  30  is not linearly moved, but is rotationally moved.  
         [0109]      FIG. 6  is a perspective view of the vibratory driving device  10  and the driven member  30  according to the third preferred embodiment.  
         [0110]     As shown in  FIG. 6 , the driven member  30  is a flattened annular member having an axial end surface  3010  as the lower surface of the driven member  30 , and the driven member  30  is supported so as to be rotatable about an axis L 1 .  
         [0111]     The vibratory driving device  10  shown in  FIG. 6  is held in such a manner that the upper end  22 A of the projecting portion  22  abuts against the axial end surface  3010  of the driven member  30  at a position near the outer circumference thereof in the condition where the first and second support members  14 A and  14 B extend in a direction perpendicular to the axial end surface  3010  of the driven member  30  and are arranged in a direction tangential to the outer circumference Of the driven member  30 .  
         [0112]     Although not shown, pressure applying section similar to that in the second preferred embodiment is provided. The description of the pressure applying section in the third preferred embodiment will be omitted herein because of similarity in configuration.  
         [0113]     As in the first preferred embodiment, the drive signals SA and SB are respectively supplied to the support members  14 A and  14 B of the vibratory driving device  10 , thereby circularly or elliptically vibrating the projecting portion  22 , so that the driven member  30  can be rotationally moved about the axis L 1  as shown by the double-headed arrow in  FIG. 6 .  
         [0114]     According to the third preferred embodiment, effects similar to those of the second preferred embodiment can be exhibited.  
         [0115]     For example, the driven member  30  to be rotationally driven by the vibratory driving device  10  may be applied to a cam cylinder adapted to be rotated to linearly drive a movable lens frame and a linear guide cylinder along an optical axis in a lens barrel of an imaging device, or may be applied to an arrow wheel for use with an iris diaphragm.  
       Fourth Preferred Embodiment  
       [0116]     A fourth preferred embodiment of the present invention will now be described with reference to  FIG. 7 .  
         [0117]     The fourth preferred embodiment is a modification of the third preferred embodiment.  
         [0118]      FIG. 7  is a perspective view of the vibratory driving device  10  according to the fourth preferred embodiment.  
         [0119]     As shown in  FIG. 7 , the fourth preferred embodiment is different from the third preferred embodiment in the point that the projecting portion  22  of the vibratory driving device  10  abuts against the outer circumferential surface  3012  of the driven member  30  in the radial direction thereof. The other configuration is similar to that of the third preferred embodiment.  
         [0120]     The vibratory driving device  10  is held in such a manner that the upper end  22 A of the projecting portion  22  abuts against the outer circumferential surface  3012  of the driven member  30  in the condition where the first and second support members  14 A and  14 B extend in a direction perpendicular to a direction tangential to the outer circumferential surface  3012  of the driven member  30  and are arranged in this tangential direction.  
         [0121]     Although not shown, pressure applying section similar to that in the second preferred embodiment is provided. The description of the pressure applying section in the fourth preferred embodiment will be omitted herein because of similarity in configuration.  
         [0122]     As in the first preferred embodiment, the drive signals SA and SB are respectively supplied to the support members  14 A and  14 B of the vibratory driving device  10 , thereby circularly or elliptically vibrating the projecting portion  22 , so that the driven member  30  can be rotationally moved about the axis L 1  as shown by the double-headed arrow in  FIG. 7 .  
         [0123]     According to the fourth preferred embodiment, effects similar to those of the second preferred embodiment can be exhibited.  
         [0124]     As a modification, the projecting portion  22  of the vibratory driving device  10  may be so arranged as to abut against the inner circumferential surface  3014  of the driven member  30  rather than the outer circumferential surface  3012 .  
       Fifth Preferred Embodiment  
       [0125]     A fifth preferred embodiment of the present invention will now be described with reference to  FIG. 8 .  
         [0126]     The fifth preferred embodiment is different from the second to fourth preferred embodiments in the point that a driven member  40  is not moved by the vibratory driving device  10 , but the vibratory driving device  10  itself moves.  
         [0127]      FIG. 8  is an elevational view of the vibratory driving device  10  and its associated parts according to the fifth preferred embodiment.  
         [0128]     As shown in  FIG. 8 , the driven member  40  and a pressure rail  42  are flat plate members, and extend in parallel to each other at a given interval. The driven member  40  has an inner surface  4002  opposed to the pressure rail  42 .  
         [0129]     Two coil springs  46  are provided under extension at the opposite ends of the driven member  40  and the opposite ends of the pressure rail  42  so as to bias the driven member  40  and the pressure rail  42  toward each other.  
         [0130]     A sliding surface member  44  is formed on the lower surface of the base  12  of the vibratory driving device  10 . The sliding surface member  44  is formed of a material having a low coefficient of friction, such as a resin material.  
         [0131]     The vibratory driving device  10  is movably interposed between the driven member  40  and the pressure rail  42  in such a manner that the upper end  22 A of the projecting portion  22  abuts against the inner surface  4002  of the driven member  40  and the sliding surface member  44  abuts against the pressure rail  42  in the condition where the first and second support members  14 A and  14 B extend in a direction perpendicular to the driven member  40  and the pressure rail  42  and are arranged in the longitudinal direction of the driven member  40  and the pressure rail  42 .  
         [0132]     As in the first preferred embodiment, the drive signals SA and SB are respectively supplied to the support members  14 A and  14 B of the vibratory driving device  10 , thereby circularly or elliptically vibrating the projecting portion  22 , so that the vibratory driving device  10  can be linearly moved along the driven member  40  so as to be guided between the driven member  40  and the pressure rail  42  as shown by the double-headed arrow in  FIG. 8 .  
         [0133]     In the fifth preferred embodiment, the coil springs  46  and the pressure rail  42  constitute pressure applying section configured to bring the driven member  40  into pressure contact with the projecting portion  22 .  
         [0134]     According to the fifth preferred embodiment, effects similar to those of the first preferred embodiment can be exhibited. Moreover, the vibratory driving device  10  itself can move, so that the flexibility of layout of the vibratory driving device  10  and the driven member  40  can be ensured.  
         [0135]     Further, the projecting portion  22  and the driven member  40  are kept in pressure contact with each other by the pressure applying section, so that the motion of the vibratory driving device  10  due to the circular or elliptical vibration of the projecting portion  22  can be reliably produced.  
         [0136]     Even in the condition that the drive signals are not supplied to the support members  14 , the projecting portion  22  and the driven member  40  are kept in pressure contact with each other by the pressure applying section, thereby holding the vibratory driving device  10  in position. Accordingly, a power consumption can be reduced.  
         [0137]     Thus, the projecting portion  22  and the driven member  40  are kept in pressure contact with each other by the pressure applying section. Accordingly, the motion of the vibratory driving device  10  is started simultaneously with starting of the circular or elliptical vibration of the projecting portion  22 . That is no backlash is present and the responsiveness of the motion of the vibratory driving device  10  can therefore be improved.  
         [0138]     Further, the pressure rail  42  is kept in pressure contact with the sliding surface member  44  to press the projecting portion  22  of the vibratory driving device  10  against the driven member  40 . Accordingly, a frictional force between the pressure rail  42  can be reduced by the sliding surface member  44 , thereby increasing the efficiency of the motion of the vibratory driving device  10 .  
         [0139]     While the coil springs  46  are used as a component of the pressure applying section in the fifth preferred embodiment, a leaf spring, magnetic spring, and elastic member and the like may be used.  
         [0140]     Further, a cross roller guide (linear rolling bearing) or the like may be provided between the base  12  and the pressure rail  42  in place of the sliding surface member  44 , thereby further reducing the frictional resistance due to the pressure applied to the vibratory driving device  10 .  
       Sixth Preferred Embodiment  
       [0141]     A sixth preferred embodiment of the present invention will now be described with reference to  FIG. 9 .  
         [0142]     In the sixth preferred embodiment, the vibratory driving device  10  is applied to a lens moving mechanism moving a lens along the optical axis thereof in a lens barrel of an imaging device, for example.  
         [0143]      FIG. 9  is a perspective view showing such a lens moving mechanism including the vibratory driving device  10  according to the sixth preferred embodiment, and  FIG. 10  is an enlarged perspective view of an essential part shown in  FIG. 9 .  
         [0144]     As shown in  FIG. 9 , the lens barrel contains a movable lens frame  50 , a main guide shaft  54 A, a subguide shaft  54 B, and the vibratory driving device  10 .  
         [0145]     A lens  52  is held in the movable lens frame  50 .  
         [0146]     The movable lens frame  50  has a bearing portion  56  through which the main guide shaft  54 A is inserted and an engaging portion  58  engaging with the subguide shaft  54 B to thereby prevent the rotation of the movable lens frame  50  about the main guide shaft  54 A.  
         [0147]     The movable lens frame  50  is supported so as to be movable along the optical axis of the lens  52  in such a manner that the bearing portion  56  and the engaging portion  58  are respectively guided along the main guide shaft  54 A and the subguide shaft  54 B.  
         [0148]     As shown in  FIG. 10 , a driven member  60  is mounted through a leaf spring  62  to the bearing portion  56 .  
         [0149]     The driven member  60  is a rectangular plate member having a thickness, a width larger than the thickness, and a length larger than the width.  
         [0150]     The leaf spring  62  has two first lugs  6202  extending in a first direction and two second lugs  6204  extending in a second direction perpendicular to the first direction.  
         [0151]     The first lugs  6202  are fixedly engaged with the bearing portion  56 , and the driven member  60  is held at its longitudinally opposite ends to the second lugs  6204 . The longitudinal direction of the driven member  60  is parallel to the axial direction of the main guide shaft  54 A.  
         [0152]     The driven member  60  has an upper surface opposed to the bearing portion  56  and a lower surface formed as a contact surface  6002  adapted to make contact with the projecting portion  22  of the vibratory driving device  10 .  
         [0153]     The vibratory driving device  10  shown in  FIGS. 9 and 10  is held in such a manner the upper end  22 A of the projecting portion  22  abuts against the contact surface  6002  of the driven member  60  in the condition where the first and second support members  14 A and  14 B extend in a direction perpendicular to the contact surface  6002  of the driven member  60  and are arranged in the longitudinal direction of the driven member  60  (the axial direction of the main guide shaft  54 A).  
         [0154]     The driven member  60  is biased toward the projecting portion  22  by a biasing force of the leaf spring  62 , so that the contact surface  6002  of the driven member  60  is kept in elastic contact with the upper end  22 A of the projecting portion  22 , thereby bringing the driven member  60  into pressure contact with the upper end  22 A of the projecting portion  22 .  
         [0155]     In the sixth preferred embodiment, the leaf spring  62  constitutes pressure applying section configured to bring the driven member  60  into pressure contact with the projecting portion  22 .  
         [0156]     As in the first preferred embodiment, the drive signals SA and SB are respectively supplied to the support members  14 A and  14 B of the vibratory driving device  10 , thereby circularly or elliptically vibrating the projecting portion  22 , so that the driven member  60  can be linearly reciprocated in the direction shown by the double-headed arrow in  FIG. 10  to thereby move the movable lens frame  50  and the lens  52  along the optical axis thereof.  
         [0157]     According to the sixth preferred embodiment, effects similar to those of the first preferred embodiment can be exhibited. Moreover, the projecting portion  22  and the driven member  60  are kept in pressure contact with each other by the pressure applying section, so that the motion of the driven member  60  due to the circular or elliptical vibration of the projecting portion  22  can be reliably produced.  
         [0158]     Even in the condition that the drive signals are not supplied to the support members  14 , the projecting portion  22  and the driven member  60  are kept in pressure contact with each other by the pressure applying section, thereby holding the movable lens frame  50  in position. Accordingly, a power consumption can be reduced.  
         [0159]     Thus, the projecting portion  22  and the driven member  60  are kept in pressure contact with each other by the pressure applying section. Accordingly, the motion of the driven member  60  is started simultaneously with starting of the circular or elliptical vibration of the projecting portion  22 . That is, no backlash is present and the responsiveness of the motion of the movable lens frame  50  can therefore be improved.  
         [0160]     While the driven member  60  is biased toward the projecting portion  22  by the pressure applying section in the sixth preferred embodiment, the projecting portion  22  may be biased toward the driven member  60  by the pressure applying section.  
         [0161]     Further, while the leaf spring  62  is used as the pressure applying section in the sixth preferred embodiment, a coil spring, magnetic spring, and elastic member and the like may be used.  
       Seventh Preferred Embodiment  
       [0162]     A seventh preferred embodiment of the present invention will now be described with reference to  FIG. 11 .  
         [0163]     The seventh preferred embodiment is a modification of the sixth preferred embodiment.  
         [0164]      FIG. 11  is a perspective view showing a lens moving mechanism including the vibratory driving device  10  according to the seventh preferred embodiment.  
         [0165]     As shown in  FIG. 11 , the seventh preferred embodiment is different from the sixth preferred embodiment in the point that all of the vibratory driving device  10 , the driven member  60 , and the leaf spring  62  are located at a different rotational position about the axis of the main guide shaft  54 A (e.g., a rotational position obtained by 90° C. clockwise rotating the position shown in  FIG. 9 ). The other configuration is similar to that of the sixth preferred embodiment.  
         [0166]     Also in the seventh preferred embodiment, effects similar to those of the sixth preferred embodiment can be exhibited.  
       Eighth Preferred Embodiment  
       [0167]     An eighth preferred embodiment of the present invention will now be described with reference to  FIG. 12 .  
         [0168]     In the eighth preferred embodiment, the vibratory driving device  10  is applied to a shake correcting mechanism moving a lens in a lens barrel of an imaging device, for example, in directions perpendicular to the optical axis of the lens.  
         [0169]      FIG. 12  is an elevational view showing such a shake correcting mechanism including the vibratory driving device  10  according to the eighth preferred embodiment.  
         [0170]     As shown in  FIG. 12 , the lens barrel contains a fixed base  70 , a movable base  72 , a lens frame  76  for holding a lens  74 , two first guide shafts  78 A and  78 B, two second guide shafts  80 A and  80 B, and first and second vibratory driving devices  10 A and  10 B.  
         [0171]     For the convenience of illustration, two phantom axes orthogonal to each other in a plane perpendicular to the optical axis of the lens  74  will be referred to as an X axis and a Y axis.  
         [0172]     The fixed base  70  is fixed to the lens barrel and the movable base  72  is movably connected through the first guide shafts  78 A and  78 B to the fixed base  70  so as to be linearly reciprocatable in the direction of the axis.  
         [0173]     The lens frame  76  is movably connected through the second guide shafts  80 A and  80 B to the movable base  72  so as to be linearly reciprocatable in the direction of the Y axis.  
         [0174]     Accordingly, the lens  74  held in the lens frame  76  is movable in an X-Y plane containing both the X axis and the Y axis.  
         [0175]     A rectangular platelike driven member  82 A extending in the direction of the X axis is supported through a leaf spring  84 A to the movable base  72 . The driven member  82 A has a first surface opposed to the leaf spring  84 A and a second surface formed opposite to the first surface as a contact surface  8202  adapted to make contact with the projecting portion  22  of the first vibratory driving device  10 A.  
         [0176]     The first vibratory driving device  10 A is held to the fixed base  70  in such a manner that the upper end  22 A of the projecting portion  22  of the first vibratory driving device  10 A abuts against the contact surface  8202  of the driven member  82 A in the condition where the first and second support members  14 A and  14 B of the first vibratory driving device  10 A extend in a direction perpendicular to the contact surface  8202  of the driven member  82 A and are arranged in the longitudinal direction of the driven member  82 A (the direction of the X axis).  
         [0177]     The driven member  82 A is biased toward the projecting portion  22  of the first vibratory driving device  10 A by a biasing force of the leaf spring  84 A, so that the contact surface  8202  of the driven member  82 A is kept in elastic contact with the upper end  22 A of the projecting portion  22 , thereby bringing the driven member  82 A into pressure contact with the upper end  22 A of the projecting portion  22 .  
         [0178]     Similarly, a rectangular platelike driven member  82 B extending in the direction of the Y axis is supported through a leaf spring  84 B to the movable lens frame  76 . The driven member  82 B has a first surface opposed to the leaf spring  84 B and a second surface formed opposite to the first surface as a contact surface  8202  adapted to make contact with the projecting portion  22  of the second vibratory driving device  10 B.  
         [0179]     The second vibratory driving device  10 B is held to the movable base  72  in such a manner that the upper end  22 A of the projecting portion  22  of the second vibratory driving device  10 B abuts against the contact surface  8202  of the driven member  82 B in the condition where the first and second support members  14 A and  14 B of the second vibratory driving device  10 B extend in a direction perpendicular to the contact surface  8202  of the driven member  82 B and are arranged in the longitudinal direction of the driven member  82 B (the direction of the Y axis).  
         [0180]     The driven member  82 B is biased toward the projecting portion  22  of the second vibratory driving device  10 B by a biasing force of the leaf spring  84 B, so that the contact surface  8202  of the driven member  82 B is kept in elastic contact with the upper end  22 A of the projecting portion  22 , thereby bringing the driven member  82 B into pressure contact with the upper end  22 A of the projecting portion  22 .  
         [0181]     In the eighth preferred embodiment, the leaf springs  84 A and  84 B constitute pressure applying section configured to bring the driven members  82 A and  82 B into pressure contact with the projecting portions  22  of the first and second vibratory driving devices  10 A and  10 B, respectively.  
         [0182]     As in the first preferred embodiment, the drive signals SA and SB are respectively supplied to the support members  14 A and  14 B of each of the first and second vibratory driving devices  10 A and  10 B, thereby circularly or elliptically vibrating the respective projecting portions  22 , so that the driven members  82 A and  82 B can be linearly reciprocated in the directions shown by the double headed arrows in  FIG. 12  to thereby move the lens frame  76  and the lens  74  in the plane perpendicular to the optical axis.  
         [0183]     According to the eighth preferred embodiment, effects similar to those of the first preferred embodiment can be exhibited. Moreover, the projecting portions  22  of the first and second vibratory driving devices  10 A and  10 B and the driven members  82 A and  82 B are respectively kept in pressure contact with each, other by the pressure applying section, so that the motions of the driven members  82 A and  82 B due to the circular or elliptical vibrations of the respective projecting portions  22  can be reliably produced.  
         [0184]     Even in the condition that the drive signals are not supplied to the support members  14 , the respective projecting portions  22  and the driven members  82 A and  82 B are kept in pressure contact with each other by the pressure applying section, thereby holding the lens frame  76  in position. Accordingly, a power consumption can be reduced.  
         [0185]     Thus, the respective projecting portions  22  and the driven members  82 A and  82 B are kept in pressure contact with each other by the pressure applying section. Accordingly, the motions of the driven members  82 A and  82 B are started simultaneously with starting of the circular or elliptical vibrations of the respective projecting portions  22 . That is, no backlash is present and the responsiveness of the motion of the lens frame  76  can therefore be improved.  
         [0186]     While the driven members  82 A and  82 B are biased toward the respective projecting portions  22  by the pressure applying section in the eighth preferred embodiment, the respective projecting portions  22  may be biased toward the driven members  82 A and  82 B by the pressure applying section.  
         [0187]     Further, while the leaf springs  84 A and  84 B are used as the pressure applying section in the eighth preferred embodiment, a coil spring, magnetic spring, and elastic member and the like may be used.  
         [0188]     Further, all of the first vibratory driving device  10 A, the driven member  82 A, and the leaf spring  84 A may be located at a different rotational position about the axis of the first guide shaft  78 A. Similarly, all of the second vibratory driving device  10 B, the driven member  82 B, and the leaf spring  84 B may be located at a different rotational position about the axis of the second guide shaft  80 A.  
         [0189]     Further, while the lens frame  76  is moved in the directions of the X and Y axes in the eighth preferred embodiment, an imaging element may be moved in the directions of the X and Y axes by using a similar configuration. Also in this case, similar effects can be exhibited.  
       Ninth Preferred Embodiment  
       [0190]     A ninth preferred embodiment of the present invention will now be described with reference to  FIG. 13 .  
         [0191]     In the ninth preferred embodiment, the vibratory driving device  10  is applied to a diaphragm mechanism limiting a light quantity in a lens barrel of an imaging device, for example.  
         [0192]      FIG. 13  is a perspective view showing such a diaphragm mechanism  90  including the vibratory driving device  10  according to the ninth preferred embodiment.  
         [0193]     As shown in  FIG. 13 , the diaphragm mechanism  90  includes a platelike base  92 , first and second diaphragm members  94 A and  94 B, first and second leaf springs  96 A and  96 B, and first and second vibratory driving devices  10 A and  10 B.  
         [0194]     The base  92  extends in a direction perpendicular to an optical axis in the lens barrel. The base  92  is formed with an opening  9202 . A plurality of guide pins  9204  project from the upper surface of the base  92 . Each of the first and second diaphragm members  94 A and  94 B is formed with a guide slot  9402  through which the guide pins  9204  are inserted. The guide slots  9402  of the first and second diaphragm members  94 A and  94 B are guided by the guide pins  9204  of the base  92 , so that the first and second diaphragm members  94 A and  94 B are movably supported on the upper surface of the base  92  so as to be reciprocatable in the direction perpendicular to the optical axis.  
         [0195]     Each of the first and second diaphragm members  94 A and  94 B is formed with a recess  9404  at a position above the opening  9202 . The recesses  9404  of the first and second diaphragm members  94 A and  94 B are opposed to each other.  
         [0196]     By moving the first and second diaphragm members  94 A and  94 B in the opposite directions so as to come away from or toward each other, the area of an aperture defined by the opposed recesses  9404  can be increased or decreased.  
         [0197]     In the ninth preferred embodiment, the first and second diaphragm members  94 A and  94 B constitute first and second driven members  98 A and  98 B, respectively, and the lower surfaces of the first and second diaphragm members  94 A and  94 B opposed to the upper surface of the base  92  constitute contact surfaces  9802  of the first and second driven members  98 A and  98 B, respectively.  
         [0198]     The first vibratory driving device  10 A is provided in a recess  9206  formed on the lower side of the base  92 .  
         [0199]     The first vibratory driving device  10 A is held to the bottom of the recess  9206  of the base  92  in such a manner that the upper end  22 A of the projecting portion  22  abuts against the contact surface  9802  of the first driven member  98 A in the condition where the first and second support members  14 A and  14 B extend in a direction perpendicular to the contact surface  9802  of the first driven member  98 A and are arranged in the longitudinal direction of the first driven member  98 A (the direction of reciprocating motion of the first driven member  98 A). In the ninth preferred embodiment, the bottom of the recess  9206  serves also as the base  12  of the first vibratory driving device  10 A.  
         [0200]     The first leaf spring  96 A is mounted on the base  92  so as to bias the first driven member  98 A at a portion opposed to the projecting portion  22  toward the projecting portion  22 . Accordingly, the first driven member  98 A is biased toward the projecting portion  22  of the first vibratory driving device  10 A by a biasing force of the first leaf spring  96 A, so that the contact surface  9802  of the first driven member  98 A is kept in elastic contact with the upper end  22 A of the projecting portion  22 , thereby bringing the first driven member  98 A into pressure contact with the upper end  22 A of the projecting portion  22 .  
         [0201]     Like the first vibratory driving device  10 A, the second vibratory driving device  10 B is provided so as to be opposed to the second diaphragm member  94 B as the second driven member  98 B.  
         [0202]     In the ninth preferred embodiment, the first and second leaf springs  96 A and  96 B constitute pressure applying section configured to bring the first and second driven members  98 A and  98 B into pressure contact with the projecting portions  22  of the first and second vibratory driving devices  10 A and  10 B, respectively.  
         [0203]     As in the first preferred embodiment, the drive signals SA and SB are respectively supplied to the support, members  14 A and  14 B of each of the first and second vibratory driving devices  10 A and  10 B, thereby circularly or elliptically vibrating the respective projecting portions  22 , so that the first and second driven members  98 A and  98 B can be linearly reciprocated in the directions shown by the double-headed arrows in  FIG. 13  to thereby move the first and second diaphragm members  94 A and  94 B away from or toward each other and accordingly increase or decrease the area of the diaphragm.  
         [0204]     According to the ninth preferred embodiment, effects similar to those of the first preferred embodiment can be exhibited. Moreover, the projecting portions  22  of the first and second vibratory driving devices  10 A and  10 B and the first and second driven members  98 A and  98 B are respectively kept in pressure contact with each other by the pressure applying section, so that the motions of the first and second driven members  98 A and  98 B due to the circular or elliptical vibrations of the respective projecting portions  22  can be reliably produced.  
         [0205]     Even in the condition that the drive signals are not supplied to the support members  14 , the respective projecting portions  22  and the first and second driven members  98 A and  98 B are kept in pressure contact with each other by the pressure applying section, thereby holding the first and second diaphragm members  94 A and  94 B in position. Accordingly, a power consumption can be reduced.  
         [0206]     Thus, the respective projecting portions  22  and the first and second driven members  98 A and  98 B are kept in pressure contact with each other by the pressure applying section. Accordingly, the motions of the first and second driven members  98 A and  98 B are started simultaneously with starting of the circular or elliptical vibrations of the respective projecting portions  22 . That is, no backlash is present and the responsiveness of the motions of the first and second diaphragm members  94 A and  94 B can therefore be improved.  
         [0207]     While the first and second driven members  98 A and  98 B are biased toward the respective projecting portions  22  by the pressure applying section in the ninth preferred embodiment, the respective projecting portions  22  may be biased toward the first and second driven members  98 A and  98 B by the pressure applying section.  
         [0208]     Further, while the first and second leaf springs  96 A and  96 B are used as the pressure applying section in the ninth preferred embodiment, a coil spring, magnetic spring, and elastic member and the like may be used.  
         [0209]     Further, while the first and second diaphragm members  94 A and  94 B are linearly reciprocated to thereby open or close the diaphragm in the ninth preferred embodiment, a driven member on which an optical filter is mounted may be linearly reciprocated in a direction perpendicular to an optical axis like the first and second diaphragm members  94 A and  94 B to thereby construct a mechanism for loading and unloading the optical filter.  
         [0210]     While the invention has been described with reference to specific embodiments, the description is illustrative and is not to be construed as limiting the scope of the invention. Various modifications and changes may occur to those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.