Patent Publication Number: US-11392205-B2

Title: Vibration actuator and vibration presenting apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is entitled to or claims the benefit of Japanese Patent Application No. 2019-207380, filed on Nov. 15, 2019, the disclosure of which including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to a vibration actuator that gives vibration depending on a pressing operation, and a vibration presenting apparatus including the vibration actuator. 
     BACKGROUND ART 
     Conventionally, at the time of operating a touch panel that is a sensing panel, there is known a configuration in which vibration is given by a vibration actuator as a touch operation feeling (a feeling of being operated by touching) to a finger pulp or the like of an operator who touches a display screen displayed on the touch panel (see PTL 1 and PTL 2). 
     PTL 1 discloses a portable terminal device in which a vibration actuator is mounted on a back surface of a touch panel via a vibration transmitting part. In this vibration actuator, a movable part is disposed inside a housing fixed to the vibration transmitting part to be reciprocally movable along a guide shaft disposed vertically with respect to the touch panel. This vibration actuator gives vibration to the finger pulp that is touching the touch panel via the vibration transmitting part by causing movable part to collide with the housing in response to operations to the touch panel. 
     Further, PTL 2 discloses a vibration presenting apparatus that gives vibration in response to operations to a touch panel. In this vibration presenting apparatus, a voice coil motor for generating vibration, a support part that is disposed with a vibration panel and compressed by a prescribed force, a damper that gives breaking work on the vibration of a vibration part, and a spring that gives a compression force to the support part and the damper are provided in parallel between the vibration panel that is the vibration part presenting vibration and a housing that supports the vibration panel. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Patent Application Laid-Open No. 2015-070729 
     PTL 2: Japanese Patent Application Laid-Open No. 2016-163854 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in such a vibration presenting apparatus, it is desired to express a vibration that provide a touch operation feeling corresponding to an application and a use situation of an operation device. 
     For example, in a case where a vibration is given in accordance with a pressing amount at the time of a pressing operation on a touch panel, it is conceivable that there is a configuration in which a strain body is provided in a portion that changes in accordance with an actual operation on the touch panel, a strain in the strain body is detected, and the vibration is given in accordance with detected amount of the strain. In this case, it is desirable that the strain body is disposed in a portion having a large amount of displacement. However, in the portion having a large amount of displacement, the strain body is also displaced in accordance with the displacement of the portion, and it is difficult to ensure a fatigue durability of the strain body. In addition, it is necessary to secure a mounting space for the strain body so as not to inhibit the displacement of a portion having a large displacement, and there is a problem that the thickness of the portion to which the strain body is mounted is increased. 
     The present invention has been made in view of these points, and an object of the present invention is to provide a vibration actuator and a vibration presenting apparatus that can stably and reliably express vibration corresponding to various touch operation feelings by a pressing operation, and achieve high reliability and compactness. 
     Solution to Problem 
     A vibration actuator of the present invention is a vibration actuator that gives vibration to a vibration presenting unit that presents vibration depending on a pressing operation, the vibration actuator comprising:
         a fixing part;   a movable part; and   an elastic support part that movably supports the movable part with respect to the fixing part;   wherein the movable part includes a support-part side fixing part fixed to the elastic support part and a presenting-unit side fixing part fixed to the vibration presenting unit,   a strain body that is strained in accordance with the pressing operation on the vibration presenting unit and a strain detection unit configured to detect strain of the strain body are provided between the support-part side fixing part and the presenting-unit side fixing part, and   the movable part is configured to vibrate by electromagnetic driving in accordance with the strain of the strain body.       

     A vibration presenting apparatus of the present invention, comprising:
         a touch panel as the vibration presenting unit; and   a vibration actuator having above configuration, that gives vibration to the touch panel.       

     Advantageous Effects of Invention 
     The present invention is capable of stably and reliably expressing vibration corresponding to various touch operation feelings by a pressing operation, and achieving high reliability and compactness. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a plan view of a vibration presenting apparatus having a vibration actuator according to Embodiment 1 of the present invention; 
         FIG. 2  is a rear perspective view of the same vibration presenting apparatus; 
         FIG. 3  is an enlarged plan view showing a stopper of the vibration presenting apparatus in  FIG. 1 ; 
         FIG. 4  is a front perspective view of the vibration actuator; 
         FIG. 5  is a rear perspective view of the same vibration actuator; 
         FIG. 6  is a front view of the same vibration actuator; 
         FIG. 7  is a front exploded perspective view of the vibration actuator; 
         FIG. 8  is a rear exploded perspective view of the same vibration actuator; 
         FIG. 9  is a front perspective view of an actuator main body of the same vibration actuator; 
         FIG. 10  is a rear perspective view of the same actuator main body; 
         FIG. 11  is a cross-sectional view taken along line B-B of  FIG. 9 ; 
         FIG. 12  is an exploded perspective view of the same actuator main body; 
         FIG. 13  is a view showing a magnetic circuit configuration of the same actuator main body; 
         FIG. 14A  is a view for explaining the operation of the same actuator main body; 
         FIG. 14B  is a view for explaining the operation of the same actuator main body; 
         FIG. 15  is a view for explaining a control unit of the same actuator main body; 
         FIG. 16  is a diagram showing wiring of a strain detector; 
         FIG. 17  is a diagram for explaining the operation of the vibration presenting apparatus having the vibration actuator according to Embodiment 1 of the present invention; 
         FIG. 18  is a rear perspective view of a vibration presenting apparatus having a vibration actuator according to Embodiment 2 of the present invention; 
         FIG. 19  is a plan view of the same vibration presenting apparatus; 
         FIG. 20  is an enlarged view showing a stopper of a vibration actuator in the same vibration presenting apparatus; 
         FIG. 21  is a front external perspective view of the same vibration actuator; 
         FIG. 22  is a rear external perspective view of the vibration actuator; 
         FIG. 23  is an exploded perspective view of the same vibration actuator; 
         FIG. 24  is a rear perspective view of the strain body; 
         FIG. 25  is a rear perspective view of the base; 
         FIG. 26  is a front perspective view of a vibration actuator according to Embodiment 3 of the present invention; 
         FIG. 27  is a rear perspective view of the same vibration actuator; 
         FIG. 28  is an exploded perspective view of the same vibration actuator. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 
     An orthogonal coordinate system (X, Y, Z) is used for explanation in the present embodiments. The same orthogonal coordinate system (X, Y, Z) is also used for showing in drawings described later. Hereinafter, the width, height, and length of vibration presenting apparatus  200  having vibration actuator  10  are lengths in X direction, Y direction, and Z direction, respectively. The width, height, and length of vibration actuator  10  are also lengths in X direction, Y direction, and Z direction, respectively. In addition, a plus side in Z direction is a direction to give vibration feedback to an operator, which is described as “front side”. A minus side in Z direction is a direction to be pressed when the operator operates, which is described as “rear side”. 
     (Basic Configuration of Vibration Presenting Apparatus  200  Having Vibration Actuator  10 ) 
     Vibration presenting apparatus  200  shown in  FIGS. 1 and 2  includes vibration actuator  10  and an operation device (touch panel  2  in the present embodiment) as a vibration presenting unit that is performed a touch operation by an operator. In vibration presenting apparatus  200 , vibration is given to the operation device in response to the touch operation to the operation device of the operator. That is, a touch operation feeling (also referred to as “haptic feeling”, “force sense”) is given to the operator who touches and operates the operation device via the operation device. 
     In the present embodiment, the operation device is touch panel  2  which displays a screen and is operated by touching the screen. Touch panel  2  is a touch panel such as an electrostatic type, a resistive film type, or an optical type. Note that, touch panel  2  detects a touch position of the operator and is controlled by the control unit  1  (see  FIG. 2 ). In the present embodiment, touch panel  2  is an electrostatic type touch panel. Control unit  1  can obtain information of the touch position of the user through a touch panel control unit which is not illustrated. Further, screen  2   a  of touch panel  2  may comprise a display unit such as a liquid crystal system, an organic EL system, an electronic paper system, a plasma system, or the like. Touch panel  2  may be controlled by the touch panel control unit. The touch panel control unit controls a display information which is not illustrated and presents image corresponding to the type of presentation vibration on the screen to the operator. 
     Vibration presenting apparatus  200  is used, for example, as an electronic device, as a touch panel device of a car navigation system. Vibration presenting apparatus  200  functions as a device that presents vibration to the operator who operates by touching screen  2   a  of touch panel  2 . At this time, any electronic device that gives the haptic feeling to the operator by presenting vibration to the operator who touches a vibration object may be used as vibration presenting apparatus  200 . For example, vibration presenting apparatus  200  may be an image device such as a smart phone, a tablet-type computer, a TV, or the like, a game machine with a touch panel, a game controller with a touch panel, or the like. 
     Specifically, in vibration presenting apparatus  200 , when screen  2   a  of touch panel  2  is operated by touching a pressing object such as the finger pulp or the like of the operator to screen  2   a  of touch panel  2 , vibration actuator  10  is driven to vibrate in response to the operation. This vibration gives the haptic feeling to the operator. 
     Vibration actuator  10  of the present embodiment gives various types of the haptic feelings corresponding to a display image operated by the operator. For example, vibration actuator  10  gives the haptic feelings as mechanical switches such as a haptic switch, alternate type switch, momentary switch, toggle switch, sliding switch, rolling switch, DIP switch and a rocker switch in accordance with an image to be touched and operated. Further, vibration actuator  10  may also give the haptic feeling of the switch with different degrees of push-in in a push type switch. 
     Note that, in vibration presenting apparatus  200 , an operation device, which does not have a display function and can be simply touched and operated by the operator, may be used instead of touch panel  2  as the operation device. 
     In vibration presenting apparatus  200  shown in  FIGS. 1 to 3 , vibration actuator  10  is disposed between touch panel  2  and base (not shown) disposed at the back surface side of touch panel  2 . Vibration actuator  10  is fixed to a base (not shown) by fixing part  30 . 
     Touch panel  2 , at the back side thereof, is fixed to strain generating member  9  of load detection module K provided in movable part  40  (see  FIG. 2 ) of actuator main body A in the vibration actuator  10 . Thus, vibration actuator  10  is disposed so as to connect each other between each of touch panel  2  and base (not shown). 
     Touch panel  2  itself can be driven integrally with movable part  40 . A direction in which the finger or the like of the operator touches and presses screen  2   a  of touch panel  2 , for example, a direction perpendicular to the screen of touch panel  2  (also referred to as a “surface perpendicular direction”) is included in the same direction as the Z direction which is the vibration direction of movable part  40  in vibration actuator  10 . In vibration actuator  10 , stoppers  400  regulate the movement of movable part  40  to the positive side in the Z direction with respect to touch panel  2 . 
     Thus, according to vibration presenting apparatus  200  in which control unit  1 , touch panel  2  and vibration actuator  10  are mounted, touch panel  2  can be directly vibrated because touch panel  2  can be directly operated, that is, touch panel  2  is driven together with movable part  40  in the same direction as a touching direction of the finger. 
     Therefore, when an image displayed on touch panel  2  is operated by touching, movable part  40  can be moved to give a vibration to be an operation feeling which corresponds to the image with respect to touch panel  2 . Note that the image may be an image of an object or the like that gives a haptic feeling to a finger or the like when touched, an image of an object that moves while giving a haptic feeling by a touch operation, or the like. 
     As a result, touch panel  2  can present vibration to the operator and express a comfortable operation. 
     Touch panel  2  of the present embodiment includes position detection unit  2   b  that detects, in a non-contact manner, a position of a finger (pressing object) of the operator who performs a pressing operation on screen  2   a  of touch panel  2 . Position detection unit  2   b  is a proximity sensor that electrically detects the presence of a pressing object in proximity. In the present embodiment, position detection unit  2   b  detects the position of the finger by detecting the capacitance with the finger of the operator. 
     A capacitive sensor used in an ordinary capacitive touch panel has a level of sensitivity that responds at a position of a finger in contact with a screen. On the other hand, position detection unit  2   b  of the present embodiment can detect the finger even in a state in which the finger is not in contact with screen  2   a  and is separated from screen  2   a  by a predetermined distance. This predetermined interval is set by setting the sensitivity of position detection unit  2   b  for detecting the capacitance to be higher than the sensitivity of a capacitance sensor used for detecting a pressing object coming into contact with a screen in an ordinary touch panel. Thus, position detection part  2   b  has detection sensitivity capable of detecting the position of the pressing object such as a finger or the like even in contact through a material whose capacitance cannot be detected. Movable part  40  of vibration actuator  10  is driven by the control unit  1 , which will be described later, based on the position of the finger detected by position detection unit  2   b.    
     &lt;Entire Configuration of Vibration Actuator  10 &gt; 
       FIGS. 4 to 8  are a front perspective view, a rear perspective view, a front view, a front exploded perspective view, and a rear exploded perspective view of vibration actuator  10 , respectively. 
     Vibration actuator  10  is a plate-shaped vibration actuator, and is disposed so as to face the back surface side of touch panel  2  in a thickness direction when the Z direction is the thickness direction. 
     Vibration actuator  10  includes control unit  1 , actuator main body A, and load detection module K. Control unit  1  may be provided in actuator main body A in the present embodiment. Load detection module K includes strain generating member  9  and strain detector  7  provided on strain generating member  9 . 
     Vibration actuator  10  detects the strain of strain generating member  9  by strain detector  7  when touch panel  2  is operated and pressed, and vibration actuator  10  vibrates in accordance with the detection result of strain detector  7  to give vibration to touch panel  2 . First, actuator main body A will be described. 
     &lt;Actuator Main Body a&gt; 
       FIG. 9  is a front perspective view of actuator main body A of the vibration actuator according to the embodiment of the present invention, and  FIG. 10  is a rear perspective view of actuator main body A.  FIG. 11  is a sectional view taken along line B-B of  FIG. 9 , and  FIG. 12  is an exploded perspective view of actuator main body A. 
     In the present embodiment, actuator main body A shown in  FIGS. 9 to 12  is mounted on vibration presenting apparatus (electronic apparatus)  200  together with control unit  1 , and functions as a vibration generating source of touch panel  2  (see  FIG. 1 ) which is an example of an operation device. 
     Actuator main body A drives movable part  40  in one direction to move movable part  40  in the direction opposite to the one direction by an urging force of the members (plate-shaped elastic parts  50 ) for generating the urging force. This allows actuator main body A to function as an electromagnetically driven electromagnetic actuator to move movable part  40  in a linear reciprocating motion (vibration). 
     It allows the operator who touches touch panel  2  to perform intuitive operations by transmitting vibrations to the operator to feel bodily sensations in response to touch operations by the operator on screen  2   a  of touch panel  2 . For example, touch panel  2  includes a touch position output part that receives a touch operation of the operator on touch panel  2  and outputs the touch position thereof. In this case, control unit  1  outputs an actuator drive signal and supplies a drive current to actuator main body A so that vibrations corresponding to the touch operations are generated based on a touch position information output by the touch position output part and a drive timing. 
     Actuator main body A that receives the driving current from control unit  1  generates vibrations corresponding to the touch positions output from touch panel  2  and transmits the vibrations to touch panel  2  to directly vibrate touch panel  2 . In this way, the operation of the operator received by touch panel  2  is received, and actuator main body A is driven correspondingly thereto. 
     By being input the actuator drive signal via control unit  1 , actuator main body A moves movable part  40  in one direction against the urging force, for example, the minus side in Z direction. Further, by being stopped the input of the actuator drive signal to actuator main body A, actuator main body A releases the urging force, and moves movable part  40  in the other direction (the plus side in Z direction) by the urging force. Actuator main body A vibrates movable part  40  and the operation device by inputting and stopping the actuator drive signal. Actuator main body A drives movable part  40  without using a magnet, and vibrates the operation device. 
     Note that, in the present embodiment, the actuator drive signal corresponds to a plurality of driving current pulses (also referred to as “current pulse”) supplied to coil  22  as a driving current for driving movable part  40  and the operation device. In actuator main body A, movable part  40  moves in one direction when the current pulse is supplied to coil  22 . By repeating this, movable part  40  vibrates. 
     Actuator main body A includes fixing part  30  having base part  32  and core assembly  20  formed by winding coil  22  around core  24 ; movable part  40  having yoke  41  of the magnetic material; and plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) as elastic support parts. Plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) elastically support movable part  40  to be movable in the vibrating direction with respect to fixing part  30 . Note that, although plate-shaped elastic parts  50  are used as the elastic support parts, the elastic support parts may not be plate-shaped as long as the elastic support parts elastically support movable part  40  movably in the vibration direction with respect to fixing part  30 . 
     Actuator main body A drives movable part  40  which is movably supported by plate-shaped elastic parts  50  so as to move in one direction with respect to fixing part  30 . Further, the movement of movable part  40  in the direction opposite to the one direction is performed by the urging force of plate-shaped elastic parts  50 . 
     Specifically, actuator main body A vibrates yoke  41  of movable part  40  by core assembly  20 . Specifically, movable part  40  is vibrated with the attraction force of energized coil  22  and excited core  24  by energized coil  22  as well as the urging force by plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ). 
     Actuator main body A is formed in a flat shape having the Z direction as the thickness direction. Actuator main body A vibrates movable part  40  in the Z direction, i.e., the thickness direction as the vibrating direction with respect to fixing part  30 , thereby bringing closer or away one of front and back surfaces spaced apart from each other in the thickness direction of actuator main body A itself with respect to the other surface in the Z direction. 
     In the present embodiment, actuator main body A moves movable part  40  to the minus side in Z direction as the one direction by the attraction force of core  24 , and moves movable part  40  to the plus side in Z direction by the urging force of plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ). 
     In actuator main body A of the present embodiment, movable part  40  is elastically supported by a plurality of plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) that is disposed along the direction orthogonal to the Z direction at point symmetrical positions with respect to the moving center of movable part  40 . However, the configuration is not limited thereto. 
     Plate-shaped elastic parts  50  are fixed between movable part  40  and fixing part  30 , includes an elastically deformable meander-shaped part, and elastically supports movable part  40  with respect to fixing part  30  to be movable in the direction opposing to at least one end of both ends (magnetic pole parts  242 ,  244 ) of core  24 . As long as plate-shaped elastic parts  50  have such a configuration, plate-shaped elastic parts  50  may be provided in any way. For example, plate-shaped elastic parts  50  may elastically support movable part  40  with respect to fixing part  30  (core assembly  20 ) to be movable in the direction opposing to one end (magnetic pole part  242  or magnetic pole part  244 ) of core  24 . Further, plate-shaped elastic parts  50 - 1 ,  50 - 2  may be disposed line symmetrically with respect to the center (the moving center) of movable part  40 , and two or more plate-shaped elastic parts  50  may be used. Each of plate-shaped elastic parts  50 - 1  and  50 - 2  are fixed to fixing part  30  at one end side and fixed to movable part  40  at the other end side to movably support movable part  40  with respect to fixing part  30  in the vibrating direction (Z direction, and it is up-and-down direction herein). 
     In the present embodiment, actuator main body A detects the displacement of touch panel  2  subjected to the pressing operation as the strain of strain generating member  9  by strain detection sensors  70 - 1  to  70 - 4  as the strain detection units. Actuator main body A moves and vibrates movable part  40  in accordance with the detected strain. 
     &lt;Fixing Part  30 &gt; 
     As shown in  FIGS. 9 to 12 , fixing part  30  includes core assembly  20  having coil  22  and core  24 , and base part  32 . 
     Core assembly  20  is fixed to base part  32 . Base part  32  is connected to movable part  40  via plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ), and supports movable part  40  to be movable in the vibrating direction. Base part  32  is a flat-shape member, and forms the bottom surface of actuator main body A, in other words, the bottom surface of vibration actuator  10 . 
     Base part  32  includes attaching parts  32   a  to which one end of each of plate-shaped elastic parts ( 50 - 1 ,  50 - 2 ) are fixed so as to sandwich core assembly  20 . Each of attaching parts  32   a  is disposed with a same space provided from core assembly  20 . Note that the space is a space to be a deforming area of plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ). 
     As shown in  FIGS. 10 and 12 , attaching parts  32   a  include fixing holes  321  for fixing plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) and fixing holes  322  for fixing base part  32  to the base side (not shown). 
     Fixing holes  322  are provided at both ends of attaching parts  32   a  so as to sandwich fixing holes  321 , and communicate with cylindrical fixing legs  324  provided to protrude from the back surface side of attaching parts  32   a . Thereby, base part  32  is entirely and stably fixed to the base (not shown) via fastening members which fits into fixing holes  322  via fixing leg portion  324 . 
     In the present embodiment, base part  32  is formed by processing a sheet metal and configured such that one side part and the other side part as attaching parts  32   a  are spaced apart from each other in the width direction (X direction) with bottom surface part  32   b  interposed therebetween. A recessed part having bottom surface part  32   b  shorter in depth than that of attaching parts  32   a  is provided between attaching parts  32   a . Inside the recessed part, that is, the space on the top surface side of bottom surface part  32   b  is for securing the elastic deforming area of plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ), and for securing a movable area of movable part  40  supported by plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ). 
     Bottom surface part  32   b  is a rectangular shape, opening part  36  is formed in the center thereof, and core assembly  20  is located inside opening part  36 . 
     Opening part  36  is a shape corresponding to the shape of core assembly  20 . Opening part  36  is formed in a square shape in the present embodiment. Thereby, entire actuator main body A can be shaped substantially into a square shape on a plan view by disposing core assembly  20  and movable part  40  in the center of actuator main body A. Note that opening part  36  may be a rectangular shape (including a square shape). 
     Split body  26   b  of bobbins  26  on the lower side of core assembly  20  and a lower-side part of coil  22  are inserted inside opening part  36 , and fixed such that core  24  is located on bottom surface part  32   b  on a side view. Thereby, length (thickness) in the Z direction becomes decreased as compared with a configuration where core assembly  20  is attached on bottom surface part  32   b . Further, core assembly  20  is fixed by screws  62  as the fastening members in a state in which a part of core assembly  20 , here, a part of the bottom surface side of core assembly  20  is fitted into opening parts  36 . Thereby, core assembly  20  is firmly fixed to bottom surface part  32   b  in a state in which core assembly  10  is not easily detached from the bottom surface part  32   b.    
     Core assembly  20  is configured by winding coil  22  around circumference of core  24  via bobbins  26 . 
     Core assembly  20  vibrates (linearly reciprocates in the Z direction) yoke  41  of movable part  40  in cooperation with plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) when coil  22  is energized. 
     In the present embodiment, core assembly  20  is formed in a rectangular plate-shaped. Magnetic pole parts  242  and  244  are disposed in both side portions of the rectangular plate-shaped spaced from each other in the longitudinal direction. 
     Magnetic pole parts  242  and  244  are disposed so as to be able to oppose to attracted surface parts  46  and  47  of movable part  40  with gap G provided therebetween in the Z direction. In the present embodiment, counter surfaces (counter surface parts)  20   a ,  20   b  as the upper surfaces are diagonally adjacent to the back surfaces of attracted surface parts  46 ,  47  of yoke  41  in the vibrating direction (Z direction) of movable part  40 . 
     As shown in  FIGS. 9 to 11 , core assembly  20  is fixed to base part  32  with a winding axis of coil  22  aligned toward the opposing direction (X direction perpendicular to the vibrating direction) of spaced attaching parts  32   a  in base part  32 . In the present embodiment, core assembly  20  is disposed in the center of base part  32 , specifically in the center of bottom surface part  32   b.    
     As shown in  FIGS. 10 to 12 , core assembly  20  is fixed to bottom surface part  32   b  such that core  24  is located on the bottom surface over opening part  36  while being in parallel to bottom surface part  32   b . Core assembly  20  is fixed in a state where coil  22  and the part (core main body  241 ) to which coil  22  is wound are located within opening part  36  of base part  32 . 
     Specifically, core assembly  20  is fixed to bottom surface part  32   b  by fastening screws  68  as fastening members through fixing holes  28  and fastening holes  33  (see  FIGS. 10 to 12 ) of bottom surface part  32   b  in a state where coil  22  is disposed in opening part  36 . Core assembly  20  and bottom surface part  32   b  sandwich coil  22 , and are joined by screws  68  as fastening members at both side parts of opening part  36  spaced from each other in the Y direction and magnetic pole parts  242 ,  244 . Fastening points of screws  68  are at two points on the axial center of coil  22 . 
     Coil  22  functions as a solenoid that is energized and generates a magnetic field at the time of driving actuator main body A. Coil  22  together with core  24  and movable part  40  forms a magnetic circuit (magnetic path) that attracts and moves movable part  40 . Note that power is supplied to coil  22  from an external power source via control unit  1 . For example, the power is supplied to coil  22  to drive actuator main body A by supplying a driving current from control unit  1  to actuator main body A. 
     Core  24  includes core main body  241  around which coil  22  is wound, and magnetic pole parts  242 ,  244  provided at both ends of core main body  241  and excited by energizing coil  22 . Core  24  may be in any types of configuration as long as it is a configuration having the length with which the both ends can function as magnetic pole parts  242 ,  244  when coil  22  is energized. For example, while it is possible to employ a straight-type (I-type) flat plate shape, core  24  of the present embodiment is formed in an H-type flat plate shape on a plan view. 
     In the case of the I-type core, in the both ends (magnetic pole parts) of the I-type core, the area of surfaces (air gap side surfaces) of attracted surface parts  46 ,  47  side, facing each other with the gap (air gap) G, become narrower. Thereby, magnetic resistance in the magnetic circuit may be increased, so that the conversion efficiency may be deteriorated. Further, when bobbins  26  are attached to core  24 , protruding parts that are positioned so that the bobbin in the longitudinal direction of core  24  does not come off from the longitudinal direction disappears or becomes smaller, so that it is necessary to provide the protruding parts separately. In the meantime, because core  24  is the H-type, the gap side surface in the both ends of core main body  241  can be expanded in the front-and-rear directions (Y directions) longer than the width of core main body  241  around which coil  22  is wound, thereby making it possible to decrease the magnetic resistance and improve the efficiency of the magnetic circuit. Further, positioning of coil  22  can be performed by simply fitting bobbins  26  between portions of magnetic pole parts  242 ,  244  extended out from core main body  241 , so that it is unnecessary to separately provide a positioning member of bobbins  26  for core  24 . 
     In core  24 , magnetic pole parts  242  and  244  are provided at each of the both ends of plate-shaped core main body  241  around which coil  22  is wound by being projected toward the direction orthogonal to the winding axis of coil  22 . 
     Core  24  is of a magnetic material made of a soft magnetic material or the like, and formed from, for example, a silicon steel sheet, permalloy, ferrite or the like. Further, core  24  may also be made of electromagnetic stainless steel, a sintered material, an MIM (metal injection mold) material, a laminated steel sheet, an electrogalvanized steel sheet (SECC), or the like. 
     Magnetic pole parts  242  and  244  are excited by energizing coil  22 , attract and move yoke  41  of movable part  40  spaced in the vibrating direction (Z direction). Specifically, magnetic pole parts  242  and  244  attract, by a magnetic flux to be generated, attracted surface parts  46  and  47  of movable part  40  oppositely disposed via gap G. 
     In the present embodiment, magnetic pole parts  242  and  244  are plate-shaped bodies extended in the Y direction that is the vertical direction with respect to core main body  241  extended in the X direction. Magnetic pole parts  242  and  244  are lengthy in the Y direction, so that the area of counter surfaces  20   a  and  20   b  opposing to yoke  41  are wider than the configuration formed in the both ends of core main body  241 . 
     Bobbins  26  are disposed to surround core main body  241  of core  24  in the direction orthogonal to the vibrating direction. Bobbins  26  are formed from a resin material, for example. This makes it possible to secure electrical insulation with other metallic members (for example, core  24 ), so that reliability as the electric circuit can be improved. By using a resin of high fluidity for the resin material, formability can be improved so that the thickness can be decreased while securing the strength of bobbins  26 . Note that split bodies  26   a  and  26   b  are mounted so as to sandwich core main body  241 , so that bobbins  26  are formed in a cylindrical shape that covers the periphery of core main body  241 . In bobbins  26 , a flange is provided to the both ends of the cylindrical body so that coil  22  is defined so as to be located on the outer circumference of core main body  241 . 
     &lt;Movable Part  40 &gt; 
     Movable part  40  is disposed to oppose to core assembly  20  with gap provided therebetween in the direction orthogonal to the vibrating direction (Z direction). Movable part  40  is provided to be able to reciprocally vibrate in the vibrating direction with respect to core assembly  20 . 
     Movable part  40  includes yoke  41 , and includes movable-part side fixing parts  54  of plate-shaped elastic parts  50 - 1  and  50 - 2  fixed to yoke  41 . 
     Movable part  40  is disposed in a state (standard normal position) being hanged while being spaced substantially in parallel and to be movable in the approaching/leaving directions (Z directions) with respect to bottom surface part  32   b  via plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ). 
     Yoke  41  is a magnetic path of the magnetic flux generated when coil  22  is energized, and is a plate-shaped body made of a magnetic material such as electromagnetic stainless steel, a sintered material, an MIM (metal injection mold) material, a laminated steel sheet, an electrogalvanized steel sheet (SECC), or the like. In the present embodiment, yoke  41  is formed by processing an SECC sheet. 
     Yoke  41  is hanged to oppose to core assembly  20  with gap G (see  FIG. 11 ) provided therebetween in the vibrating direction (Z direction) by plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) respectively fixed to attracted surface parts  46  and  47  spaced from each other in the X direction. 
     Yoke  41  includes surface-part fixing parts  44  fixed to strain generating member  9 , and attracted surface parts  46  and  47  oppositely disposed to magnetic pole parts  242  and  244 , in order to be attached to the operation device (see touch panel  2  shown in  FIG. 1 ). Yoke  41  is formed in a rectangular frame shape having opening part  48  in the center thereof, by surface-part fixing parts  44  and attracted surface parts  46 ,  47 . 
     Opening part  48  opposes to coil  22 . In the present embodiment, opening part  48  is located right above coil  22 , and the opening shape of opening part  48  is a shape to which coil  22  part of core assembly  20  can be inserted when yoke  41  moves to bottom surface part  32   b  side. 
     By configuring yoke  41  to have opening part  48 , the thickness of actuator main body A, and hence entire vibration actuator  10 , can be decreased as compared to a case having no opening part  48 . 
     Further, core assembly  20  is located within opening part  48 , so that yoke  41  is not disposed in the vicinity of coil  22 . Therefore, it is possible to suppress deterioration in the conversion efficiency due to the magnetic flux leakage leaked from coil  22 , so that high output can be achieved. 
     Surface-part fixing part  44  includes fixing surfaces  44   a  fixed to body frame parts  95   a  of strain generating member  9 . Surface-part fixing part  44  has a plate shape. In the present embodiment, surface-part fixing part  44  is disposed to face touch panel  2  at a portion surrounding the center of the operation surface of touch panel  2 , and is fixed to touch panel  2  via strain generating member  9 . 
     Specifically, the edge part of fixing surface  44   a  of surface-part fixing part  44  is fixed in surface contact with the long side part of body frame parts  95   a  of strain generating member  9 . In the present embodiment, fixing surface  44   a  has a trapezoidal shape in a plan view, and is fixed to strain generating member  9  via fastening members such as screws  69  (see  FIGS. 4 to 6 ) inserted into surface-part fixing holes  42 . 
     By joining surface-part fixing parts  44  to touch panel  2  via strain generating member  9 , the center extending in the vibration direction (Z direction) of movable part  40  is preferably disposed so as to be positioned on the same line as the center of the operation surface of touch panel  2 . Thus, the entire front surface of movable part  40  can receive the displacement of touch panel  2  via strain generating member  9 . 
     In the present embodiment, in a front view of movable part  40 , surface-part fixing holes  42  are provided at or near part which is the outside around core assembly  20  and on a diagonal line. 
     Attracted surface parts  46  and  47  are attracted to magnetic pole parts  242  and  244  magnetized in core assembly  20 , and plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) are fixed thereto. 
     Movable-part side fixing parts  54  of plate-shaped elastic parts  50 - 1  and  50 - 2  are fixed by being laminated, respectively, on attracted surface parts  46  and  47 . Attracted surface parts  46  and  47  are provided with cutouts  49  escaping from the heads of screws  68  of core assembly  20  when moved to bottom surface part  32   b  side. 
     Thereby, even when movable part  40  moves to bottom surface part  32   b  side and attracted surface parts  46 ,  47  approach magnetic pole parts  242 ,  244 , attracted surface parts  46 ,  47  are not to be in contact with screws  68  that fix magnetic pole parts  242 ,  244  to bottom surface part  32   b , so that a movable area of yoke  41  in the Z direction can be secured for that. 
     &lt;Plate-Shaped Elastic Part  50  ( 50 - 1 ,  50 - 2 )&gt; 
     Plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) movably support movable part  40  with respect to fixing part  30 . Plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) support the upper surface of movable part  40  so as to be parallel to each other at the same depth as the upper surface of fixing part  30 , or at the lower surface side of the upper surface of fixing part  30  (the upper surface of core assembly  20  in this embodiment). Plate-shaped elastic parts  50 - 1  and  50 - 2  have a symmetrical shape with respect to the center of movable part  40 , and are members formed in the same manner in the present embodiment. 
     Plate-shaped elastic parts  50  are arranged yoke  41  substantially in parallel so as to face to magnetic pole parts  242  and  244  of core  24  of fixing part  30  with a gap G. Plate-shaped elastic parts  50  movably support the lower surface of movable part  40  in the vibrating direction at the position of bottom surface part  32   b  side of the substantially same depth level as the depth level of the upper surface of core assembly  20 . 
     Plate-shaped elastic part  50  is a plate spring (spring plate member), and includes fixing-part side fixing part  52 , movable-part side fixing part  54 , and meander-shaped elastic arm parts  56  that communicate fixing-part side fixing part  52  with movable-part side fixing part  54 . 
     Plate-shaped elastic part  50  attaches fixing-part side fixing part  52  to the surface of attaching parts  32   a , attaches movable-part side fixing parts  54  to the surfaces of the attracted surface parts  46  and  47  of yoke  41 , and attaches movable part  40  with meander-shaped elastic arm parts  56  parallel to bottom surface part  32   b.    
     Fixing-part side fixing parts  52  are joined and fixed by screws  62  in surface contact with attaching parts  32   a , and movable-part side fixing parts  54  are joined and fixed by screws  64  in surface contact with the attracted surface parts  46  and  47 . 
     Meander-shaped elastic arm part  56  is an arm part having a meander-shaped part. Since meander-shaped elastic arm part  56  is the arm part having the meander-shaped part, meander-shaped elastic arm part  56  secures a length that allows deformation necessary for vibration of movable part  40  between fixing-part side fixing part  52  and movable-part side fixing part  54  and in a plane (a plane formed in the X direction and the Y direction) orthogonal to the vibration direction. 
     Meander-shaped elastic arm part  56  in the present embodiment has a shape which extends in the opposing direction of fixing-part side fixing parts  52  and movable-part side fixing parts  54  and folds back. In meander-shaped elastic arm part  56 , ends respectively joined to fixing-part side fixing parts  52  and movable-part side fixing parts  54  are formed at positions shifted in the Y direction. Meander-shaped elastic arm parts  56  are disposed in a position of point symmetry or line symmetry with respect to the center of movable part  40 . 
     Thereby, movable part  40  is supported from both sides by meander-shaped elastic arm parts  56  having meander-shaped springs, so that it is possible to disperse the stress at the time of elastic deformation. That is, plate-shaped elastic parts  50  can move movable part  40  in the vibrating direction (Z direction) without tilting with respect to core assembly  20 , thereby making it possible to improve reliability of the vibrating state. 
     Each of plate-shaped elastic parts  50  includes at least two or more meander-shaped elastic arm parts  56 . Thereby, compared to a case where each of plate-shaped elastic parts  50  includes only one meander-shaped elastic arm part, plate-shaped elastic parts  50  make it possible to improve the reliability by dispersing the stress at the time of elastic deformation and to improve the stability by balancing the support for movable part  40  better. 
     Plate-shaped elastic parts  50  in the present embodiment are formed from a magnetic material. Further, movable-part side fixing parts  54  of plate-shaped elastic parts  50  are disposed at positions opposing to both ends (magnetic pole parts  242 ,  244 ) of core  24  in a coil winding axis direction or on the upper side thereof and function as a magnetic path. In the present embodiment, movable-part side fixing parts  54  are fixed by being laminated on the upper side of the attracted surface parts  46  and  47 . This makes it possible to increase thickness (Z direction, the length of the vibrating direction) H (see  FIG. 11 ) of the attracted surface parts  46  and  47  opposing to the magnetic pole parts  242 ,  244  of core assembly as the thickness of the magnetic material. 
     In the present embodiment, the thickness of plate-shaped elastic parts  50  and the thickness of yoke  41  are the same, so that the cross sectional area of the magnetic material portion opposing to magnetic pole parts  242 ,  244  can be doubled. Thereby, compared to a case where the plate spring is nonmagnetic, it is possible to ease the degradation of properties due to magnetic saturation in magnetic circuits and to improve the output, by expanding the magnetic circuit. 
       FIG. 13  is a diagram showing a magnetic circuit of vibration actuator  10 . Note that  FIG. 13  is a perspective view of actuator main body A, showing the portion cut by the line B-B in  FIG. 9 . The portion of the magnetic circuit not shown has the same magnetic flux flow M as the portion of the magnetic circuit shown. Further,  FIGS. 14A and 14B  are a cross-sectional views schematically showing the movement of movable part  40  by the magnetic circuit. In particular,  FIG. 14A  is a diagram showing a state in which movable part  40  is held at a position separated from core assembly  20  by the plate-shaped elastic parts  50 .  FIG. 14B  shows a movable part  40  which is moved is attracted to core assembly  20  side by the magnetomotive force by the magnetic circuit. 
     Specifically, when coil  22  is energized, core  24  is excited and a magnetic field is generated, thereby forming magnetic poles in both ends of core  24 . For example, in  FIG. 13 , magnetic pole part  242  is the N-pole, and magnetic pole part  244  is the S-pole in core  24 . Thereby, the magnetic circuit indicated by magnetic flux flow M is formed between core assembly  20  and yoke  41 . Magnetic flux flow M in the magnetic circuit flows to attracted surface part  46  of opposing yoke  41  from magnetic pole part  242 , passes through surface-part fixing parts  44  of yoke  41 , and reaches magnetic pole part  244  opposing to attracted surface part  47  from attracted surface part  47 . In the present embodiment, plate-shaped elastic parts  50  are also of magnetic materials. Thereby, the magnetic flux (illustrated as magnetic flux flow M) flown to attracted surface part  46  passes through attracted surface part  46  of yoke  41  and movable-part side fixing parts  54 , reaching attracted surface part  46  and both ends of movable-part side fixing parts  54  of plate-shaped elastic part  50 - 2  via surface-part fixing parts  44  from both ends of attracted surface part  47 . 
     Thereby, according to the principle of electromagnetic solenoid, magnetic pole parts  242 ,  244  of core assembly  20  generate attraction force F for attracting attracted surface parts  46 ,  47  of yoke  41 . Thereupon, attracted surface parts  46 ,  47  of yoke  41  are attracted to both of magnetic pole parts  242 ,  244  of core assembly  20 . Thereby, coil  22  is inserted into opening part  48  of yoke  41 , and movable part  40  including yoke  41  moves in F-direction against the urging force of plate-shaped elastic parts  50  (see  FIG. 14A  and  FIG. 14B ). 
     In the meantime, when energization to coil  22  is stopped, the magnetic field disappears, attraction force F of core assembly  20  for movable part  40  is lost, and movable part  40  is moved back to the original position (moved to F-direction minus side) by the urging force of plate-shaped elastic parts  50 . 
     By repeating such action described above, in actuator main body A, movable part  40  reciprocally moves in a linear manner and generates vibration in the vibrating direction (Z direction). 
     By reciprocating movable part  40  in a linear manner, touch panel  2  as the operation device to which movable part  40  is fixed, is also displaced in the Z direction following movable part  40 . In the present embodiment, the displacement of movable part  40  due to driving, that is, the displacement of touch panel  2  ranges from 0.03 mm to 0.3 mm. 
     The range of this displacement is a range in which vibration corresponding to the display pressed by the operator can be applied on screen  2   a  of touch panel  2  as the operation device. For example, when the display to be pressed by the operator on screen  2   a  is a mechanical button or various switches, the range of amplitude is such that the same haptic feeling can be given as when the mechanical button or various switches are actually pressed. This range is set based on the fact that a small displacement of the amplitude of movable part  40  results in inadequate haptic feeling, and a large displacement of the amplitude of movable part  40  results in discomfort. 
     In actuator main body A, it is possible to increase the efficiency of the magnetic circuit and achieve high output by disposing attracted surface parts  46 ,  47  of yoke  41  adjacent to magnetic pole parts  242 ,  244  of core assembly  20 . Further, actuator main body A uses no magnet, so that a low-cost configuration can be achieved. 
     Meander-shaped springs that are plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) enable dispersion of the stress, so that the reliability can be improved. Especially, because movable part  40  is supported by a plurality of plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ), more effective dispersion of the stress is possible. Thus, actuator main body A is capable of providing a more direct sense of touch by driving up-and-down direction thereto to the operator who touches screen  2   a  in up-and-down direction. 
     Core assembly  20  having core  24  around which coil  22  is wound is fixed to fixing part  30 . This core assembly  20  is disposed in opening part  48  of yoke  41  of movable part  40  which is movably supported in Z direction by plate-shaped elastic parts  50  with respect to fixing part  30 . Thereby, it becomes unnecessary to stack members provided for each of the fixing part and movable part in Z direction (e.g., place the coil and magnet opposite each other in Z direction) in order to generate magnetism to drive the movable part in Z direction, so that the thickness in Z direction can be reduced in actuator main body A as the electromagnetic actuator. Further, by reciprocating linear movement of movable part  40 , the operation device can give the vibration as the haptic feeling without using a magnet. Thus, the design becomes simple because the support structure is simple, it is possible to save space, it is possible to reduce the thickness of actuator main body A. Further, because it is not an actuator using a magnet, it is possible to reduce the cost as compared with the configuration using a magnet. 
     Hereinafter, the driving principle of actuator main body A will simply be described. Actuator main body A, that is, vibration actuator  10  can be driven by generating a resonance phenomenon with a pulse by using following motion expression and circuit expression. Note that the actions are not resonance driven but for expressing operational feeling of mechanical switches displayed on the touch panel. In the present embodiment, the actions are driven by inputting a plurality of current pulses through control unit  1 . 
     Note that movable part  40  in actuator main body A performs reciprocating motion based on Expressions (1) and (2). 
     
       
         
           
             
               
                 
                   
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             m: Mass [kg] 
             x(t): Displacement [m] 
             K f : Thrust constant [N/A] 
             i(t): Current [A] 
             K sp : Spring constant [N/m] 
             D: Attenuation coefficient [N/(m/s)] 
           
         
       
    
     
       
         
           
             
               
                 
                   
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             e(t): Voltage [V] 
             R: Resistance [Ω] 
             L: Inductance [H] 
             K e : Counter electromotive force constant [V/(rad/s)] 
           
         
       
    
     That is, mass “m” [kg], displacement “x(t)” [m], thrust constant “K f ” [N/A], current “i(t)” [A], spring constant “K sp ” [N/m], and attenuation coefficient “D” [N/(m/s)] in actuator main body A can be changed as appropriate within the range satisfying Expression (1). Also, voltage “e(t)” [V], resistance “R” [Ω], inductance “L” [H], and counter electromotive force constant “K e ” [V/(rad/s)] can be changed as appropriate within the range satisfying Expression (2). 
     Thus, actuator main body A is determined based on mass “m” of movable part  40 , and spring constant K sp  of metal springs (elastic bodies; plate springs in the present embodiment) as plate-shaped elastic parts  50 . 
     Further, in actuator main body A, screws  62  and  64  as fastening members are used for fixing base part  32  and plate-shaped elastic parts  50  and for fixing plate-shaped elastic parts  50  and movable part  40 . Thereby, plate-shaped elastic parts  50  required to be firmly fixed to fixing part  30  and movable part  40  for allowing movable part  40  to drive can be firmly fixed mechanically in a state capable of reworking. 
     According to actuator main body A, it includes fixing part  30  having coil  22  and core  24  around which coil  22  is wound and whose both ends protrude from coil  22 . Further, vibration actuator  10  includes movable part  40  which is disposed close to counter surfaces  20   a  and  20   b  of magnetic pole parts  242  and  244 , which are both end portions of core  24 , with a gap G therebetween in a direction intersecting the winding shaft of coil  22 , includes yoke  41  made of a magnetic body, and can be fixed to an operation touch surface portion operated by touch. 
     Actuator main body A is fixed between movable part  40  and fixing part  30 , and elastically supports movable part  40  with respect to fixing part  30  so as to be movable in a direction facing magnetic pole parts  242  and  244 , by plate-shaped elastic part  50  having meander-shaped elastic arm parts  56  to be elastically deformed. Thus, even in a case where actuator main body A is attached to the touch panel which is the operation touch surface portion, it is possible to provide the user with a suitable operation feeling at the time of operating the touch panel while achieving a reduction in thickness and cost. 
     &lt;Control Unit  1 &gt; 
     Control unit  1  controls actuator main body A, and hence vibration actuator  10  that drives the operation device (touch panel  2  in  FIG. 1 ) supported elastically to vibrate in one direction in the vibrating direction. 
     Control unit  1  supplies a driving current to vibration actuator  10  in response to the touch operation of the operation device to generate a magnetic field, and moves elastically vibratable movable part  40  in one direction with respect to fixing part  30 , here in Z direction minus side. Thus, when the operator touches the operation device, control unit  1  gives vibrations as the haptic feeling. In the present embodiment, the touch operation is a signal detected by strain detection sensors  70 , but in addition to this, the touch operation may be detected by using a signal detected by sensor  80 . Alternatively, for example, the touch operation may be a signal indicating a touch condition input from touch panel  2 . 
     In the present embodiment, control unit  1  supplies a single current pulse or a plurality of current pulses to coil  22  as an actuator drive signal for driving vibration actuator  10 . In the present embodiment, the actuator drive signal is constituted by a train of a plurality of current pulses. 
     By supplying the current pulse to coil  22  by control unit  1 , movable part  40  is displaced by the magnetic attraction force against the urging force of plate-shaped elastic parts  50 , by being drawn back to coil  22  side, that is, to Z direction minus side. Following this, touch panel  2  also moves to Z direction minus side with respect to base (not shown) which fixing part  30  is fixed to. 
     Further, by stopping the supply of the driving current to coil  22 , the urging force is released, a holding state of movable part  40  at a position in Z direction minus side relative to a standard position is released. Thereby, movable part  40  is urged to move from its maximum displacement position in Z direction minus side to the direction (Z direction plus side) opposite to the drawn direction (Z direction minus side) due to the urging force of the plate-shaped elastic parts  50 , thus feeding back the vibration. 
     Control unit  1  is capable of generating various types of vibration shapes by the amplitude of each pulse in a single current pulse or a train of a plurality of current pulses, each wavelength, each supply timing, and the like, and supplying the vibration shapes to actuator main body A as actuator drive signals. Thus, the vibration of the actuator main body A is given to the operator as a feeling. 
     Control unit  1  includes, for example, a current pulse supply unit, a voltage pulse application unit. 
     The current pulse supply unit supplies a plurality of drive current pulses to coil  22  of vibration actuator  10  as a drive current for driving the operation device in response to a touch operation of the operation device (touch panel  2 ). 
     The voltage pulse application unit intermittently applies a plurality of control voltage pulses each generating a single current pulse or a train of a plurality of current pulses constituting the actuator drive signals to the current pulse supply unit. 
       FIG. 15  is a view for explaining the control unit of the actuator main body and showing an example of a drive circuit for driving the vibration actuator. 
     In control unit  1  shown in  FIG. 15 , switching element  12  as a current pulse supply unit configured by a MOSFET (metal-oxide-semiconductor field-effect transistor), signal generating unit (Signal generation)  14  as a voltage pulse application unit, resistors R 1 , R 2 , and SBD (Schottky Barrier Diodes) are provided. 
     In control unit  1 , signal generating unit  14  connected to a power supply voltage Vcc is connected to a gate of switching element  12 . Switching element  12  is a discharge changeover switch. Switching element  12  is connected to vibration actuator  10  and SBD, and connected to vibration actuator  10 , specifically, the actuator main body A (shown by [Actuator] in  FIG. 15 ) to which a voltage is supplied from the power supply unit Vact. 
     Note that, although not shown, control unit  1  may include a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like for control operation of the components of the vibration presenting device. The CPU reads a program corresponding to processing content from the ROM, develops the program in the RAM, and cooperates with the developed program to control operation of the components of the vibration presenting device including vibration actuator  10 . At this time, various data including various vibrations attenuation periods pattern stored in a storage unit (not shown) are referenced. The storage unit (not shown) may be configured by, for example, a nonvolatile semiconductor memory (so-called flash memory) or the like. For example, pulse waveform data of various plural patterns of a plurality of pulse trains is stored in the storage unit, ROM, RAM, or the like. The ROM stores various programs for control the vibration presenting device including a vibration presenting program for presenting vibration by driving actuator main body A. The vibration presentation program includes, for example, a program for reading pulse waveform data to generate an actuator drive signal that generates vibration corresponding to the touch information when information indicating a touch condition is input from strain detection sensors  70 . Further, the vibration presentation program includes, for example, a program for generating an actuator drive signal corresponding to the touch information by combining the read data, and a program for supplying the generated actuator drive signal to the coil. The actuator drive signal is applied to coil  22  via a driver that drives actuator main body A as a combination of a plurality of current pulses. The CPU may use these programs and data to control the operation of the components of the vibration presenting device, and may control the current pulse supply unit and the voltage pulse application unit. For example, the signals from strain detection sensors  70 - 1  to  70 - 4  are amplified by the amplification unit, analog-to-digital converted by the conversion unit, and output to the CPU to vibrate vibration actuator  10  by the drive circuit shown in  FIG. 15 . 
     Control unit  1  supplies the current pulse to coil  22  to drive movable part  40  in one direction of vibration. By supplying the current pulse to coil  22 , movable part  40  is displaced in one direction of the vibrating direction against the urging force of plate-shaped elastic parts  50 . During the supply of the current pulse, the displacement in one direction of the vibrating direction of movable part  40  is continued. By stopping the supply of the current pulse, that is, turning off the input of the current pulse to coil  22 , the force to displace in one direction of the vibration direction of movable part  40  (Z direction) is released. Turning off the input of the current pulse means that the timing in which the voltage generating the current pulse is turned off. At the moment the voltage is switched off, the current pulses are not completely switched off but attenuated. 
     Movable part  40  is displaced to move to the other direction (Z direction plus side) of the vibrating direction by the urging force of plate-shaped elastic parts  50  accumulated at the maximum displaceable position in the drawn direction (Z direction minus side). Strong vibration is propagated to the operation device through movable part  40  which has moved to the other direction side which is the operation device side, and the haptic feeling is given to the operator. 
     Control unit  1  supplies one or more current pulses to coil  22  in response to touching screen  2   a  by the operator based on the information from strain detection sensors  70 . In the vibration of movable part  40 , by supplying the first pulse, and further supplying the pulse after supplying the first pulse, control unit  1  adjusts the vibration or the like that remains and continues after stopping the supply of the first pulse. 
     &lt;Load Detection Module K&gt; 
     Returning to  FIGS. 4 to 8 , the load detection module K will be described. 
     Load detection module K is interposed between movable part  40  of actuator main body A and touch panel  2 , and is fixed to movable part  40  and touch panel  2 . 
     Load detection module K detects strain generated in strain generating member  9  by strain detection body  7  in accordance with pressing operation of touch panel  2 . The detected strain is output to control unit  1 , and control unit  1  drives actuator main body A in accordance with the strain to generate vibration. 
     &lt;Strain Generating Member  9 &gt; 
     Strain generating member  9  includes movable-part side fixing parts (support-part side fixing parts)  92  fixed to surface-part fixing parts  44  of movable part  40 , and presenting-unit side fixing parts  94  fixed to touch panel  2  as a vibration presenting unit. 
     Strain generating member  9  functions as a strain body that generates strain when an external force is applied by a pressing operation to touch panel  2 . In the present embodiment, strain generating member  9  is formed in a rectangular frame-like plate shape by processing a sheet metal. This shape is a shape that a portion subjected to the pressing operation in touch panel  2  is surrounded at the back surface side of touch panel  2  when strain generating member  9  is fixed to planar touch panel  2 . In the present embodiment, strain generating member  9  is formed of a sheet metal harder than plate-shaped elastic part  50  of movable part  40 . 
     In strain generating member  9 , connecting-arm parts  95   b  are provided so as to extend in the longitudinal direction from four corners of body frame parts  95   a  having a flat rectangular frame shape. Strain generating member  9  includes movable-part side fixing parts  92  provided at each part of body frame parts  95   a  to which the base end parts of connecting-arm parts  95   b  are connected. Strain generating member  9  is fixed to surface-part fixing parts  44  via movable-part side fixing parts  92 . In strain generating member  9  of the present embodiment, body frame parts  95   a  are fixed to surface-part fixing parts  44  of movable part  40 , and thus the function as a strain generating body is mainly exhibited by connecting-arm parts  95   b . Strain generating member  9  includes presenting-unit side fixing parts  94  at each tip part of connecting-arm parts  95   b , and is fixed to touch panel  2  by presenting-unit side fixing parts  94 . 
     Strain generating member  9  includes ribs  95   c  provided vertically to body frame parts  95   a  along an outer edge part separated in the longitudinal direction of body frame parts  95   a . Body frame parts  95   a  are in a state being reinforced by ribs  95   c.    
     Strain generating member  9  is joined and fixed to touch panel  2  at presenting-unit side fixing parts  94 , so that presenting-unit side fixing parts  94  are joined to touch panel  2  at a portion surrounding the center of the operation surface of touch panel  2 . Further, strain generating member  9  is fixed to movable part  40  via movable-part side fixing parts  92  in an inner region surrounded by presenting-unit side fixing parts  94 . 
     &lt;Strain Detector  7 &gt; 
     Strain detector  7  is provided integrally with strain generating member  9 , and has a strain detection part for detecting strain generated by a load applied to strain generating member  9  as the strain body in order to drive actuator main body A. 
     Strain detector  7  is, for example, a flexible printed circuit board (hereinafter, also referred to as “FPC”)  72  on which a plurality of strain detection sensors  70  ( 70 - 1  to  70 - 4 ) as strain detection units is mounted. 
     Strain detection sensor  70  detects, as the pressing amount of touch panel  2 , the pressing amount of strain generating member  9  that is displaced together with movable part  40  when touch panel  2  to which surface-part fixing parts  44  are fixed via strain generating member  9  is operated. 
     Strain detection sensors  70  ( 70 - 1  to  70 - 4 ) detect strain of strain generating member  9  due to deformation of plate-shaped elastic part  50  when the strain detection sensor is pushed into bottom surface part  32   b  side together with surface-part fixing parts  44 . The detected strain is output to a control device or the like, and coil  22  is energized to move yoke  41  by attraction so that the moving amount of movable part  40  corresponds to the strain. 
     In the present embodiment, control unit  1  determines the moving amount of touch panel  2  by using the strain detected by strain detection sensors  70  to realize vibration feedback for the touch, but the present invention is not limited thereto. In addition, control unit  1  may be configured to detect the pressing amount against plate-shaped elastic part  50  by a moving amount corresponding to the actual moving amount of the operation device by using a sensor that detects touch of the operator with the operation device, and to realize expression of a more natural feeling by using the detection result. 
     Further, the vibration cycle of movable part  40  (which may include touch panel  2  as the operation device) when the drive current pulse is supplied by the current pulse supply unit of control unit  1  may be adjusted based on the detection result of the sensor that detects the touch operation of the operator, that is, the pressing amount of movable part  40 , by using strain detection sensors  70 . In addition to strain detection sensors  70 , an operation signal indicating an operation state may be output to control unit  1  so that vibration corresponding to the display form is generated in conjunction with the display form of the touch position of the operator detected on touch panel  2 , and control unit  1  may perform control in accordance with the operation signal. 
     Strain detector  7  mainly uses connecting-arm parts  95   b  of strain generating member  9  as a strain generating body, detects the strain, and outputs the detected strain to control unit  1 . 
     Specifically, strain detector  7  includes FPC  72  disposed so as to extend over four corners of body frame parts  95   a  on body frame parts  95   a  of strain generating member  9 , and formed in a staple-shaped (U-shaped). That is, FPC  72  is provided such that short parts  72   b  extend in the height direction perpendicularly to long parts  72   a  from both sides of long parts  72   a  extending in the width direction, and is formed in a U shape by long parts  72   a  and short parts  72   b.    
     In strain detector  7 , strain detection sensors  70 - 1  to  70 - 4  are disposed between movable-part side fixing parts  92  and presenting-unit side fixing parts  94 , respectively. Specifically, strain detection sensors  70 - 1  to  70 - 4  are mounted on connecting-arm parts  95   b  functioning as the strain body, and detect strain in connecting-arm parts  95   b  of strain generating member  9 , respectively. 
     Strain detection sensors  70 - 1  to  70 - 4  may be provided at one position in load detection module K, but are preferably provided at a plurality of positions. When vibration actuator  10  is attached to the vibration presenting unit (touch panel  2 ), it is preferable that strain detection sensors are provided at least three or more positions so as to radially surround the center of the operation surface of the vibration presenting unit at equal intervals. Thus, vibration actuator  10  can receive the displacement of touch panel  2  to be pressed by the surface and accurately detect the displacement. 
     In the present embodiment, strain detection sensors  70 - 1  to  70 - 4  are provided at  4  positions in the vicinity of presenting-unit side fixing parts  94  which is a fixing position to touch panel  2 , and detect strain of a frame-shaped corner portion surrounding the center of the pressing operation region of touch panel  2 . Therefore, when a rectangular touch panel display is used as the vibration presenting unit as in touch panel  2 , actuator main body A can be attached to the display in a well-balanced manner via load detection module K. Thus, the strain direction of strain generating member  9  can be stably matched with the direction perpendicular to the surface. 
       FIG. 16  is a diagram showing wiring of strain detector  7 . 
     Strain detection sensors  70 - 1  to  70 - 4  mounted on FPC  72  are disposed on strain generating member  9  and are located on the same plane. 
     Each of strain detection sensors  70 - 1  to  70 - 4  includes a plurality of strain gauge units (R-A 1  to R-A 4 , R-B 1  to R-B 4 , R-C 1  to R-C 4 , and R-D 1  to R-D 4 ), and is a full-bridge connection type strain detection sensor. 
     In FPC  72 , strain detection sensors  70 - 1  to  70 - 4  are connected in parallel to the power supply voltages Vcc and GND, are connected in parallel to each other, and are connected so as to output a change amount of an electrical resistance value that changes due to application of a load. Thus, the outputs from strain detection sensors  70 - 1  to  70 - 4  are averaged, and stable behavior is obtained. Further, the output values are substantially equalized in temperature for each of strain detection sensors  70 - 1  to  70 - 4 , and the temperature stability can be improved. 
     &lt;Effect of Vibration Actuator  10 &gt; 
     Effect 1 
     Strain detection sensors  70  are provided on connecting-arm parts  95   b  as the strain body whose strain is detected by strain detection sensors  70 . That is, strain detection sensors  70  and the strain body are disposed between touch panel  2  as the vibration presenting unit and movable part  40 , in other words, between movable-part side fixing parts  92  and presenting-unit side fixing parts  94 . 
     Thus, strain detection sensors  70  are not disposed in actuator main body A, and the strain body is separated from plate-shaped elastic part  50 , so that the strain detection object does not receive the mass of movable part  40  and the vibration specification of plate-shaped elastic part  50  is not affected. Thus, the design of actuator main body A does not become difficult, and various specifications of actuator main body A can be realized. 
     Further, in movable part  40 , strain detection sensors  70  and the strain body are disposed between a fixing portion to plate-shaped elastic part  50  (corresponding to movable-part side fixing parts  92 ) and a fixing portion to the vibration presenting unit (corresponding to presenting-unit side fixing parts  94 ). Thus, strain detection sensors  70  and the strain body can be integrated with actuator main body A, and a product of the vibration actuator with complete haptic feeling expression can be realized. 
     Effect 2 
     Actuator main body A is fixed to touch panel  2 , which is the vibration presenting unit, via load detection module K in which strain detection sensors  70  and strain generating member  9  are integrated. Thus, vibration actuator  10  can be assembled after load detection module K and actuator main body A are separately assembled. Thus, compared to a configuration in which strain detection sensors  70  and the strain body are a part of movable part of the actuator main body, it is not necessary to assemble the actuator after strain detection sensors  70  are assembled, or to perform reverse process, and therefore it is possible to improve assemblability. 
     Further, since strain generating member  9  can be changed in accordance with the shape of the vibration presenting unit, the degree of freedom in design can be improved. 
     Effect 3 
     Movable part  40  of actuator main body A is driven in a direction perpendicular to the surface of touch panel  2  to be the vibration presenting unit. Specifically, unlike a case where touch panel  2  as the vibration presenting unit is moved in a direction parallel to the screen (touch surface), touch panel  2  and movable part  40  are bent in the direction perpendicular to the surface by the load of the vibration actuator. Thus, for example, when the behavior of the switch is expressed, the deflection can also be expressed, and a realistic haptic expression close to the actual operation of the switch or the like can be realized. 
     Effect 4 
     Strain generating member  9  is a plate-shaped spring plate member. Thus, even when vibration is repeatedly given, metal fatigue can be mitigated and reliability can be improved. 
     Further, in vibration actuator  10 , strain generating member  9  is formed of an integral spring plate member. Thus, it is possible to increase the positional accuracy of the arrangement positions of strain detection sensors  70 - 1  to  70 - 4  on connecting-arm parts  95   b  of strain generating member  9 , and it is possible to improve the accuracy at the time of assembly. That is, unlike the case where connecting-arm parts  95   b  as the strain bodies to be the detection target portions in strain generating member  9  are configured to be separated into a plurality of parts, no variation occurs at the time of assembly, and the assemblability can be improved. 
     Stoppers  400  prevent touch panel  2  to which movable part  40  is fixed via load detection module K and fixing part  30  connected to movable part  40  via plate-shaped elastic part from being separated from each other by a predetermined interval or more. The predetermined interval is a length at which plate-shaped elastic part  50  and strain generating member  9  are not plastically deformed. Thus, stoppers  400  function when an external impact is applied to vibration actuator  10  to prevent a load from being applied to strain generating member  9 , thereby capable of suppressing the plastic deformation of strain generating member  9 , preventing strain generating member  9  and strain detection sensors  70  from being damaged, and improving reliability. 
     Effect 5 
     The present embodiment includes position detection unit  2   b  (see  FIGS. 1 and 2 ) that detects the position of the finger of the operator who performs the pressing operation on screen  2   a  of touch panel  2  in a non-contact manner, specifically, by the capacitance with the finger of the operator. Position detection unit  2   b  has sensitivity of capacitance detection that reacts even when there is a distance between the finger and touch panel  2 . That is, vibration presenting apparatus  200  can detect the position of the finger by position detection unit  2   b  even when the finger is in a floating state. 
     For example, as shown in  FIG. 17 , when vibration presenting apparatus  200  is operated by a finger U wearing a glove T, the finger U is in a floating state (hover state). 
     In a general structure in which a position of a finger operating a touch panel is detected using a capacitance sensor, a glove other than a glove dedicated to a finger on which the glove is worn does not respond to capacitance, and thus a distance between the finger and the touch panel is substantially long. This distance corresponds to distance H 2  in  FIG. 17 . 
     In contrast, according to the present embodiment, position detection unit  2   b  detects the position of finger U even in a state in which finger U touches touch panel  2  via glove T (actually, a state in which finger U is pressed by the glove), that is, even in a state in which finger U is in a hover state. That is, vibration presenting apparatus  200  can detect the position of the operating finger by touch panel  2  which is the vibration presenting unit even in the case of an operation in a situation in which capacitance detection is impossible, such as an operation through glove T or the like. 
     In addition, vibration presenting apparatus  200  (which may be vibration actuator  10 ) detects the operation by the pressing operation with finger U wearing glove T, that is, detects that finger U is being pressed with the pressing load by strain detection sensors  70 . 
     Thus, according to the present embodiment, it is possible to detect the position of finger U even in a state in which finger U is separated from screen  2   a , accurately detect that finger U is pressed, and apply vibration feedback to touch panel  2  by the vibration of vibration actuator  10 . Vibration presenting apparatus  200  can more effectively increase the operation feeling even in an operation with gloves. Further, by having a function of reacting even when there is a distance between finger U and touch panel  2  and a function of detecting that finger U is pressed by the detection of strain detection sensors  70 , it is possible to suppress erroneous reaction and erroneous operation in the detection of the pressing operation. 
     Thus, vibration presenting apparatus  200  according to the present embodiment realizes a realistic haptic feeling expression such as the haptic feeling of a switch by a realistic haptic feeling expression based on load detection. 
     Embodiment 2 
       FIG. 18  is a rear perspective view of vibration presenting apparatus  200 A having a vibration actuator according to Embodiment 2 of the present invention, and  FIG. 19  is a plan view of vibration presenting apparatus  200 A. Further,  FIG. 20  is an enlarged view showing a stopper of vibration actuator  10 A in vibration presenting apparatus  200 A. Further,  FIGS. 21 to 23  are a front external perspective view, a rear external perspective view, and an exploded perspective view of vibration actuator  10 A, respectively. Note that, in vibration actuator  10 A shown in  FIG. 23 , for convenience, strain detector  7  of load detection module K 1  has the same configuration as that of vibration actuator  10 , and is provided on the strain generating member in the same manner, and thus is not shown. Further,  FIG. 24  is a rear perspective view of strain generating member  9 A, and  FIG. 25  is a rear perspective view of the base part. 
     Vibration presenting apparatus  200 A shown in  FIGS. 18 to 20  is different from vibration presenting apparatus  200  of Embodiment 1 only in the configuration of vibration actuator  10 A. Specifically, in vibration presenting apparatus  200 A, the function of stopper  400  provided in touch panel  2  as the vibration presenting unit is provided in vibration actuator  10 A of vibration presenting apparatus  200 A. The other basic configuration of vibration presenting apparatus  200 A is the same as the configuration of vibration presenting apparatus  200 . Therefore, hereinafter, a configuration different from that of vibration presenting apparatus  200  will be described, and the same configuration will be denoted by the same reference numeral and description thereof will be omitted. 
     Vibration presenting apparatus  200 A includes vibration actuator  10 A and an operation device (touch panel  2  in the present embodiment) that is performed a touch operation by an operator. 
     In vibration presenting apparatus  200 A, similarly to vibration presenting apparatus  200 , when screen  2   a  of touch panel  2  is touched and operated by the finger pulp or the like of the operator, vibration actuator  10 A is driven to vibrate in response to the operation. This vibration provides the operator with a touch operation feeling (“haptic feeling” or “force sense”). Similar to vibrating actuator  10 , vibration actuator  10 A of the present embodiment provides various types of haptic feelings corresponding to the display image operated by the operator. Note that touch panel  2  may be an operation device which does not have a display function and can be simply touched and operated by the operator. 
     Vibration actuator  10 A is a plate-shaped vibration actuator, and is disposed so as to face the back surface side touch panel  2 , that is, the surface on the opposite side of screen  2   a  which is the operation surface, in the thickness direction when the Z direction is the thickness direction. 
     Vibration actuator  10 A includes actuator main body A 1  having control unit  1  and load detection module K 1 . 
     Actuator main body A 1  includes fixing part  30 A having base part  32 A and core assembly  20  formed by winding coil  22  around core  24 ; movable part  40  having yoke  41  made of a magnetic material; and plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ). Plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) elastically support movable part  40  to be movable in the vibration direction with respect to fixing part  30 A. Load detection module K 1  includes strain generating member  9 A and strain detector  7  provided to strain generating member  9 . Vibration actuator  10 A detects the displacement of strain generating member  9 A when touch panel  2  is pressed. In the present embodiment, the strain is detected by strain detector  7 , movable part  40  of actuator main body A 1  vibrates in accordance with the detection result of strain detector  7  to give vibration to touch panel  2 . Note that, actuator main body A 1  has the same magnetic circuit as that of actuator main body A, and movable part  40  reciprocates by the driving principle based on the expressions (1) and (2) as in actuator main body A. 
     Compared to actuator main body A, actuator main body A 1  shown in  FIGS. 18 to 24  is different in that actuator main body A 1  includes movement regulated parts  37 ; and movement regulating parts  96  which engage with each other in each of strain generating member  9 A of load detection module K 1  and base part  32 A of fixing part  30 . 
     Strain generating member  9 A includes rectangular frame-shaped body frame parts  95   a  fixed to yoke  41  of movable part  40  of actuator main body A 1 ; connecting-arm parts  95   b  extending from the corners of body frame parts  95   a  along the longitudinal direction; and movement regulating parts  96  provided on the tip side of connecting-arm parts  95   b.    
     In the present embodiment, as shown in  FIGS. 18 to 22 , movement regulating parts  96  are provided at a position close to presenting-unit side fixing part  94  in connecting-arm parts  95   b . Specifically, as shown in  FIG. 20 , movement regulating parts  96  extend in a direction orthogonal to the extending direction of connecting-arm parts  95   b  at a position that is further away from movable-part side fixing parts  92  than the position of presenting-unit side fixing part  94  on connecting-arm parts  95   b . Movement regulating parts  96  are provided so as to be positioned on the rear surface side than attaching parts  32 Aa of base part  32 . 
     Similarly to base member  3 , base part  32 A is a long member having a rectangular flat shape. In the present embodiment, base part  32 A is formed by processing a sheet metal and includes concave bottom surface part  32 Ab provided with attaching parts  32 Aa at both ends. Opening part  36 A is provided in the center of bottom surface  32 Ab, and core assembly  20  is disposed in opening part  36 A. In attaching parts  32 Aa, movement regulated parts  37  which are engaged with movement regulating parts  96  and regulates the movement in the opposite direction to each other, is protruded. 
     Movement regulated parts  37  are provided so as to protrude in the longitudinal direction from attaching parts  32 Aa, and are provided so as to be positioned at positions overlapping movement regulating parts  96  of strain generating member  9 A on a surface opposite to a surface on which strain generating member  9 A is attached in the Z direction (vibration direction). 
     Therefore, when an impact is applied to vibration presenting apparatus  200 A, touch panel  2  moves in the direction perpendicular to the surface, and strain generating member  9 A moves toward touch panel  2 , movement regulating parts  96  that move along with the movement of strain generating member  9 A come into contact with movement regulated parts  37 . Thus, the movement of movement regulating parts  96  are suppressed, the movement of strain generating member  9 A itself is also suppressed, and the load is prevented from being applied to strain generating member  9 A. 
     That is, in the movement of strain generating member  9 A in the vibration direction when an impact is received in vibration presenting apparatus  200 A, the movement toward fixing part  30 A side (the minus side in the Z direction) is suppressed by the mutual components coming into contact with each other, such as screws  68  on fixing part  30 A side coming into contact with yoke  41 . On the other hand, the movement of strain generating member  9 A toward fixing part  30 A (the minus side in the Z direction) when an impact is received in vibration presenting apparatus  200 A, is regulated by movement regulating parts  96  of strain generating member  9 A engaging with movement regulated parts  37  on the back surface side of movement regulated parts  37 . 
     Thus, the plastic deformation of strain generating member  9 A is suppressed, the deformation of strain generating member  9 A and its breakage are prevented, and the reliability is improved. 
     Therefore, compared to Embodiment 1, it is possible to manufacture vibration actuator  10 A and vibration presenting apparatus  200 A having impact resistance without providing a stopper function in touch panel  2  itself which is the vibration presenting unit to which vibration actuator  10 A is attached. Further, according to vibration actuator  10 A and vibration presenting apparatus  200 A of Embodiment 2, it is possible to obtain the same effects as Effects 1 and 3 of Embodiment 1. Further, in the present embodiment, similarly to position detection unit  2   b  of touch panel  2  of vibration presenting apparatus  200 , touch panel  2  may include a position detection unit that detects the position of the finger (pressing object) of the operator pressing screen  2   a  of touch panel  2  in a non-contact manner. Thus, it is possible to obtain the same effect as Effect 5 of Embodiment 1. 
     Embodiment 3 
       FIG. 26  is a front perspective view of vibration actuator  10 B according to Embodiment 3 of the present invention,  FIG. 27  is a rear perspective view of vibration actuator  10 B, and  FIG. 28  is an exploded perspective view of vibration actuator  10 B. 
     In vibration actuator  10 B of Embodiment 3, the function of load detection module K in vibration actuator  10  is provided in movable part  40  of actuator main body A which is an electromagnetic actuator. 
     Compared to actuator main body A, vibration actuator  10 B differs only in the configuration of yoke  41 B with the detection portion of movable part  40 B. Therefore, hereinafter, only a configuration of vibration actuator  10 B different from that of actuator main body A will be described, and the same components as those of actuator main body A will be denoted by the same reference numerals and the same names, and description thereof will be omitted. 
     In the present embodiment, vibration actuator  10 B is mounted on an electronic apparatus to be a vibration presenting apparatus together with control unit  1 , and functions as a vibration generating source of touch panel  2  (see  FIG. 1 ) which is an example of an operation device. 
     Similarly to vibration actuator  10  of Embodiment 1, vibration actuator  10 B drives movable part  40 B in one direction, and moves movable part  40 B in the direction opposite to the one direction by the urging force of the members (plate-shaped elastic parts  50 ) for generating the urging force. Thus, vibration actuator  10 B functions as an electromagnetic actuator to move movable part  40 B in a linear reciprocating motion (vibration). Note that, vibration actuator  10 B has the same magnetic circuit as that of actuator main body A of Embodiment 1, and movable part  40  reciprocates by the driving principle based on the expressions (1) and (2) as in actuator main body A. 
     Vibration actuator  10 B includes fixing part  30  having base part  32  and core assembly  20  formed by winding coil  22  around core  24 ; movable part  40 B having yoke  41 B with the detection portion for a magnetic material; and plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ). Plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) elastically support movable part  40 B to be movable in the vibration direction with respect to fixing part  30 . 
     Vibration actuator  10 B vibrates yoke  41 B with the detection portion of movable part  40 B by core assembly  20 . Specifically, similarly to vibration actuator  10 , movable part  40 B is vibrated with the attraction force of energized coil  22  and excited core  24  by energized coil  22  as well as the urging force by plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ). 
     Vibration actuator  10 B detects the displacement of touch panel  2  (see  FIG. 1 ) subjected to the pressing operation as the strain of extension parts  45  which are integrated with the movable part  40 B by strain detection sensors  70 - 1  to  70 - 4  as the strain detection units. Movable part  40 B can be moved and vibrated in accordance with the detected strain, and the vibration, as an operation feeling, is fed back to the touch panel (similar to touch panel  2  of  FIG. 1 ) to which movable part  40 B is fixed. 
     Detailed description of plate-shaped elastic parts  50 - 1  and  50 - 2  and fixing part  30  will be omitted because they have the same configuration and function as those of actuator main body A of vibration actuator  10  in Embodiment 1. Further, since the joining positions or the like of plate-shaped elastic parts  50 - 1  and  50 - 2  with respect to movable part  40 B are the same as those of actuator main body A of vibration actuator  10 , the description thereof will be omitted. 
     Movable part  40 B is disposed to oppose to core assembly  20  with gap provided therebetween in the direction orthogonal to the vibrating direction (Z direction). Movable part  40 B is provided to be able to reciprocally vibrate in the vibrating direction with respect to core assembly  20  via plate-shaped elastic parts  50 - 1  and  50 - 2 . 
     Movable part  40 B includes yoke  41 B with the detection portion, and includes movable-part side fixing parts  54  of plate-shaped elastic parts  50 - 1  and  50 - 2  fixed to yoke  41 B with the detection portion. 
     Similarly to movable part  40  of vibration actuator  10 , movable part  40 B is disposed in a state (standard normal position) being hanged while being spaced substantially in parallel and to be movable in the approaching/leaving directions (Z directions) with respect to bottom surface part  32   b  via plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ). 
     Yoke  41 B with the detection portion has the same function as yoke  41  in Embodiment 1, and functions as a magnetic path of the magnetic flux generated when coil  22  is energized. Yoke  41 B with the detection portion is a rectangular frame-like plate shape body made of a magnetic material such as electromagnetic stainless steel, a sintered material, an MIM (metal injection mold) material, a laminated steel sheet, an electrogalvanized steel sheet (SECC), or the like. In the present embodiment, yoke  41 B with the detection portion is formed by processing an SECC sheet. 
     Yoke  41 B with the detection portion is hanged to oppose to core assembly  20  with gap provided therebetween in the vibrating direction (Z direction) by plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) respectively fixed to attracted surface parts  46  and  47  spaced from each other in the X direction. 
     Yoke  41 B with the detection portion includes yoke main body  4  joined to plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ); extension parts  45  extending from yoke main body  4  and being fixed to an operation device (see touch panel  2  shown in  FIG. 1 ) at attaching holes  452  on the tip side thereof; and strain detection sensors  70 . 
     Yoke main body  4  includes attracted surface parts  46 B and  47 B oppositely disposed to magnetic pole parts  242  and  244 ; and frame forming parts  43   a ,  43   b  installed across in an orthogonal direction to attracted surface parts  46 B,  47 B between both end parts of attracted surface parts  46 B,  47 B. Yoke main body  4  is formed in a rectangular frame shape body having opening part  48 B in the center thereof, by attracted surface parts  46 B,  47 B and frame forming parts  43   a ,  43   b.    
     Opening part  48 B opposes to coil  22 . In the present embodiment, opening part  48 B is located right above coil  22 , and the opening shape of opening part  48 B is a shape to which coil  22  part of core assembly  20  can be inserted when yoke  41 B with the detection portion moves to bottom surface part  32   b  side. 
     Since yoke main body  4  has opening part  48 B, the thickness of vibration actuator  10 , and hence entire vibration actuator  10 , can be decreased as compared to a case having no opening part  48 B. 
     Further, core assembly  20  is located within opening part  48 B, so that yoke  41 B is not disposed in the vicinity of coil  22 . Therefore, it is possible to suppress deterioration in the conversion efficiency due to the magnetic flux leakage leaked from coil  22 , so that high output can be achieved. 
     Attracted surface parts  46 B and  47 B have the same functions as attracted surface parts  46  and  47  of vibration actuator  10 . Attracted surface parts  46 B and  47 B are attracted to magnetic pole parts  242  and  244  magnetized in core assembly  20 , and plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) are fixed thereto. Since plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) are fixed to attracted surface parts  46 B,  47 B of yoke main body  4 , attracted surface parts  46 B,  47 B, that is, yoke main body  4  itself functions as a movable-part side fixing part (support-part side fixing part). 
     Movable-part side fixing parts  54  of plate-shaped elastic parts  50 - 1  and  50 - 2  are fixed by being laminated, respectively, on attracted surface parts  46 B and  47 B. Attracted surface parts  46 B and  47 B are provided with cutouts  49 B escaping from the heads of screws  68  of core assembly  20  when yoke main body  4  is moved to bottom surface part  32   b  side. 
     Thereby, even when movable part  40 B moves to bottom surface part  32   b  side and attracted surface parts  46 B,  47 B approach magnetic pole parts  242 ,  244 , attracted surface parts  46 B,  47 B are not to be in contact with screws  68  that fix magnetic pole parts  242 ,  244  to bottom surface part  32   b , so that movable area of yoke  41 B with the detection portion in the Z direction can be secured for that. 
     Note that, also in Embodiment 3, the thickness of yoke  41 B is the same as that of plate-shaped elastic parts  50 , the cross sectional area of the magnetic material portion opposing to magnetic pole parts  242 ,  244  are double. Thereby, compared to a case where the plate spring is nonmagnetic, it is possible to ease the degradation of properties due to magnetic saturation in magnetic circuits and to improve the output, by expanding the magnetic circuit. 
     In movable part  40 B, extension parts  45  connect fixing portions to the plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) and fixing portions to the operation device (in the present embodiment, attaching holes  452 ), and are provided integrally with both. 
     Extension parts  45  are formed of a metallic plate integrated with yoke main body  4 , and are formed so as to be positioned on the same plane as attracted surface parts  46 B,  47 B of yoke main body  4 . In the present embodiment, attaching holes  452  on the tip sides of extension parts  45  and the mounting positions of movable-part side fixing parts  54  of plate-shaped elastic parts  50  ( 50 - 1 ,  50 - 2 ) in attracted surface parts  46 B,  47 B are provided at the same height position. In the present embodiment, extension parts  45  are provided so as to extend in the radial direction from the corner portions of yoke main body  4  with the center of yoke main body  4  (the center extending in the vibration direction (Z direction)) as the center. 
     Extension parts  45  are portions to be strain bodies of strain detection sensors  70 . 
     When vibration is given in accordance with the pressing amount at the time of the pressing operation on the touch panel, extension parts  45  are distorted in accordance with the actual operation on the touch panel. 
     In a front view of movable part  40 B, attaching holes  452  are positioned at or near part which is the outside around core assembly  20  and on a diagonal line. 
     Attaching holes  452  are fixed to touch panel  2  (vibration presenting unit, see  FIG. 1 ). In the present embodiment, attaching holes  452  are provided at  4  positions surrounding yoke main body  4  of movable part  40 B at four corners, and are respectively fixed to the vibration presenting unit. 
     By joining attaching holes  452  to touch panel  2 , the center of movable part  40 B is preferably disposed so as to be positioned on the same line as the center of the operation surface of touch panel  2 . Thus, extension parts  45  can receive the displacement of touch panel  2 . 
     Strain detection sensors  70  ( 70 - 1  to  70 - 4 ) are provided on extension parts  45 . That is, strain detection sensors  70  ( 70 - 1  to  70 - 4 ) are disposed between attracted surface parts  46 B and  47 B each having the movable-part side fixing part and attaching holes  452  as the presenting-unit side fixing part. 
     Strain detection sensors  70  ( 70 - 1  to  70 - 4 ) are mounted on extension parts  45  functioning as the strain bodies, and detect strain of extension parts  45  when movable part  40 B is pushed into bottom surface part  32   b  side. Note that, the detected strain is output to control unit  1  as in Embodiment 1, and vibration actuator  10 B vibrates in accordance with the strain. Further, the connection of strain detection sensors  70  ( 70 - 1  to  70 - 4 ) are preferably the same as that of Embodiment 1. 
     According to vibration actuator  10 B of Embodiment 3, the same effects as the Effects 1, 3 and 4 in vibration actuator  10  can be obtained. Further, in the present embodiment, similarly to position detection unit  2   b  of touch panel  2  of vibration presenting apparatus  200 , touch panel  2  may include a position detection unit that detects the position of the finger (pressing object) of the operator pressing screen  2   a  of touch panel  2  in a non-contact manner. Thus, it is possible to obtain the same effect as Effect 5 of Embodiment 1. 
     Further, according to each of the embodiments, it is possible to reduce the cost without using a magnet or the like, and it is possible to express vibration of various touch operation feelings while reducing the cost of the entire apparatus. 
     Note that, although it is preferable that a plurality of plate-shaped elastic parts  50  is fixed at symmetrical positions with respect to the center of movable part  40 ,  40 B, as described above, one plate-shaped elastic part  50  may support movable part  40  so as to be able to vibrate with respect to fixing part  30 . Plate-shaped elastic part  50  may include at least two or more arm portions connecting movable part  40  and fixing part  30  and having meander-shaped elastic arm part  56 . Plate-shaped elastic part  50  may be made of a magnetic material. In this case, movable-part side fixing parts  54  of plate-shaped elastic part  50  are disposed in the winding axis direction of coil  22  or in a direction orthogonal to the winding axis direction with respect to both end portions of core  24 , and constitute a magnetic path together with core  24  when coil  22  is energized. 
     Further, in the configuration of each of vibration actuator  10 ,  10 A and  10 B, rivets may be used instead of the screws  62 ,  64 ,  68  and  69  as the fastening members used for fixing base part  32  and  32 B to plate-shaped elastic part  50 , and, fixing plate-shaped elastic part  50  to movable part  40  and  40 B. Rivets consist of a head and a body without a screw part, and are inserted into holes of a members, and members are joined together by plastically deforming by caulking the opposite end of the rivets. The caulking may be performed using, for example, a press machine, a dedicated tool, or the like. 
     Based on strain data obtained by strain detection sensors  70 , it may be possible to perform correction of the period of the input pulse due to individual differences among the components in vibration actuators  10 ,  10 A, and  10 B. 
     In the present embodiment, although the driving direction of vibration actuators  10  and  10 A driven and controlled by control unit  1  is the Z direction, the present invention is not limited thereto. It is possible to obtain the effects such as the above-described efficient driving and strengthening of the vibration even in the direction parallel to the touch surface of the operator, specifically, X-direction or Y direction. 
     Further, by driving movable part  40  and  40 B in one direction and then moving movable part  40  in the direction opposite to the one direction by the urging force of the members (plate-shaped elastic parts  50 ) for generating the urging force, vibration actuators  10 ,  10 A, and  10 B of each embodiment are electromagnetic actuators that linearly reciprocate (vibrate) movable parts  40  and  40 B, but are not limited to this configuration. The vibration actuator may have any configuration as long as it has a configuration in which the movable part is supported by the plate-shaped elastic part such as a plate-like spring with respect to the fixing part in a freely vibrating manner and the movable part is attached to the touch panel or the like which is the vibration presenting (vibration feedback) target. 
     The arrangement positions of strain detection sensors  70 - 1  to  70 - 4  in vibration actuators  10 A and  10 B of Embodiments 2 and 3 are also provided in the same arrangement as strain detection sensors  70 - 1  to  70 - 4  of vibration actuator  10 . That is, it is preferable that strain detection sensors  70 - 1  to  70 - 4  in vibration actuators  10 A and  10 B are provided at least three or more positions so as to radially surround the center of the operation surface (screen  2   a ) of touch panel  2  to be the vibration presenting unit at equal intervals. Thus, vibration actuator  10  can receive the displacement of touch panel  2  to be pressed by the surface and accurately detect the displacement. In vibration actuators  10 A and  10 B, similarly to vibration actuator  10 , strain detection sensors  70 - 1  to  70 - 4  are positioned at four corner portions surrounding the center of the pressing operation region of touch panel  2  in a frame shape, and the same operation and effect as those of vibration actuator  10  are obtained. 
     As described above, embodiments of the present invention have been described. Note that the above description is illustrative of a preferred embodiment of the present invention, and the scope of the present invention is not limited thereto. That is, the configuration of the device and the shape of each part are only examples, and it is obvious that various modifications and additions to these examples are possible within the scope of the present invention. 
     INDUSTRIAL APPLICABILITY 
     The vibration actuator according to the present invention has an effect capable of giving vibrations in accordance with various touch feelings and being easily assembled. For example, in automotive products and industrial equipment, it is useful for operation devices in which operations are input by touching a finger or the like to an image on a screen, such as a touch display device equipped with a touch panel device that can feed back a sense of operation similar to the sense of operation when touching various images such as a mechanical switch displayed on the image. 
     REFERENCE SIGNS LIST 
     
         
           1  control unit 
           2  touch panel (vibration presenting unit) 
           2   a  screen (operation surface) 
           2   b  position detection unit 
           4  yoke main body 
           7  strain detector 
           9 ,  9 A strain generating member 
           10 ,  10 A,  10 B vibration actuator 
           12  switching element 
           14  signal generating unit 
           20  core assembly 
           20   a ,  20   b  counter surface 
           22  coil 
           24  core 
           26  bobbins 
           26   a ,  26   b  split body 
           28 ,  321 ,  322  fixing hole 
           30 ,  30 A fixing part 
           32 ,  32 A,  32 B base part 
           32   a ,  32 Aa attaching part 
           32   b ,  32 Ab bottom surface part 
           33  fastening hole 
           36 ,  36 A opening part 
           37  movement regulated part 
           40 ,  40 B movable part 
           41  yoke 
           41 B yoke with detector 
           42  surface-part fixing hole 
           43   a ,  43   b  frame forming part 
           44  surface-part fixing part 
           44   a  fixing surface 
           45  extension part (strain body) 
           46 ,  46 B,  47 ,  47 B attracted surface part (support-part side fixing part) 
           48 ,  48 B opening part 
           49 ,  49 B cutout 
           50 ,  50 - 1 ,  50 - 2  plate-shaped elastic part (elastic support part) 
           52  fixing-part side fixing part 
           54  movable-part side fixing part 
           56  meander-shaped elastic arm part 
           62 ,  64 ,  68 ,  69  screw 
           70  strain detection sensor (strain detection unit) 
           72  FPC 
           92  movable-part side fixing part (support-part side fixing part) 
           94  presenting-unit side fixing part 
           95   a  body frame part 
           95   b  connecting-arm part 
           95   c  rib 
           96  movement regulating part 
           200 ,  200 A vibration presenting apparatus 
           241  core main body 
           242 ,  244  magnetic pole part 
           400  stopper 
           452  attaching hole (presenting-unit side fixing part)