Patent Publication Number: US-2015059474-A1

Title: Functional device, electronic apparatus, and moving object

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2013-177655 filed on Aug. 29, 2013. The entire disclosure of Japanese Patent Application No. 2013-177655 is hereby incorporated herein by reference. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a functional device, an electronic apparatus, and a moving object. 
     2. Related Art 
     In related art, as a functional device that detects a physical quantity of acceleration or the like used as a functional device, a functional device having a structure including a fixed electrode, a movable member that can be displaced in a fixed direction, and a movable electrode provided with a gap adjacent to the fixed electrode and provided on the movable member has been known. 
     In the functional device, the gap between the fixed electrode and the movable electrode provided on the movable member changes with displacement of the movable member, a change in capacitance caused between the fixed electrode and the movable electrode due to the change of the gap is detected, and thereby, a change of a physical quantity of acceleration or the like is measured. 
     For example, Patent Document 1 (U.S. Pat. No. 6,065,341) discloses a functional device having a structure in which a movable member, a beam part extended from the movable member, and a fixed part to which the beam part is connected are provided in line symmetry, and a stopper part that regulates displacement of the movable member is provided on a surface opposed to the movable member inside the beam part bent to form a polygonal shape. 
     However, in the above described functional device, displacement in a rotation direction generated in the movable member in a plan view of the movable member is not easily regulated. Therefore, when excessive acceleration or the like is applied and the displacement in the rotation direction is generated in the movable member, there is a problem that the fixed electrode and the movable electrode provided on the movable member come into contact and the capacitance generated between both of the electrodes is lost, and measurement as the functional device is stopped. Further, the electrodes may be broken due to contact between the fixed electrode and the movable electrode. The problems may occur not only in the functional device but also in an MEMS vibrator having the same configuration. 
     SUMMARY 
     An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples. 
     Application Example 1 
     A functional device according to this application example includes a movable member that can be displaced along a first axis, a movable electrode part extended from the movable member, a fixed electrode part provided to be opposed to the movable electrode part, and a stopper part that regulates displacement of the movable member, wherein a projecting part projecting along the first axis is provided on the movable member, and a distance between an end of the projecting part and the stopper part is shorter than a distance between the movable electrode part and the fixed electrode part. 
     According to the functional device, when the movable member is displaced along the first axis, the projecting part projecting from the movable member and the stopper part come into contact before contact between the movable electrode part and the fixed electrode part, and thereby, contact between the movable electrode part and the fixed electrode part may be suppressed. 
     Thus, when a force of acceleration or the like is applied to the functional device and the movable member is excessively displaced, sticking between the electrode parts and breakage of the electrode parts due to contact between the fixed electrode part and the movable electrode part or the like may be suppressed. Further, the functional device that may suppress a loss of capacitance caused between the movable electrode part and the fixed electrode part and continuously measure the physical quantity of acceleration or the like may be obtained. 
     Application Example 2 
     In the functional device according to the application example described above, it is preferable that a fixed part connected to the movable member is provided, and the fixed part and the stopper part are integrally provided. 
     According to the functional device, when the movable member is displaced along the first axis, the projecting part projecting from the movable member and the stopper part provided integrally with the fixed part come into contact before contact between the movable electrode part and the fixed electrode part, and thereby, contact between the fixed electrode part and the movable electrode part may be suppressed. 
     Thus, when a force of acceleration or the like is applied to the functional device and the movable member is excessively displaced, sticking between the electrode parts and breakage of the electrode parts due to contact between the fixed electrode part and the movable electrode part or the like may be suppressed. Further, the functional device that may suppress a loss of capacitance caused between the fixed electrode part and the movable electrode part and continuously measure the physical quantity of acceleration or the like may be obtained. 
     Application Example 3 
     In the functional device according to the application example described above, it is preferable that a first fixed part and a second fixed part connected to the movable member are provided, and the first fixed part and the second fixed part are provided on both sides of the stopper part, and the first fixed part and the movable member are connected by a first beam part and the second fixed part and the movable member are connected by a second beam part. 
     According to the functional device, the movable member is fixed by the first beam part connected to the first fixed part and the second beam part connected to the second fixed part, and thereby, displacement of the movable member in an in-plane rotation direction in parallel to the first axis may be suppressed. 
     Application Example 4 
     In the functional device according to the application example described above, it is preferable that at least a part of the projecting part is provided between the first beam part and the second beam part. 
     According to the functional device, when the displacement of the movable member in the in-plane rotation direction in parallel to the first axis is caused, the projecting part projecting from the movable member comes into contact with the first beam part and the second beam part, and thereby, the displacement in the in-plane rotation direction may be suppressed. 
     Application Example 5 
     In the functional device according to the application example described above, it is preferable that the movable member and the stopper part are at the same potential. 
     According to the functional device, the stopper part and the movable member are at the same potential, and thereby, when the movable member comes into contact with the stopper part, fluctuations in capacitance between the fixed electrode part and the movable electrode part provided on the movable member may be suppressed. Therefore, when the movable member comes into contact with the stopper part, fluctuations in capacitance between the movable member and the fixed electrode part may be suppressed. Thus, the functional device in which an influence on the measurement of the physical quantity of acceleration or the like is suppressed even when the movable member and the stopper part come into contact may be obtained. 
     Application Example 6 
     In the functional device according to the application example described above, it is preferable that a projection is provided on at least one of opposed surfaces of the stopper part and the projection part. 
     According to the functional device, compared to a contact area when the stopper part and the movable member come into contact, the contact area when the stopper part and the movable member come into contact in the case where the projection is provided on the movable member may be made smaller. Thereby, an impact when the stopper part and the movable member come into contact may be reduced. Further, sticking between the stopper part and the movable member may be suppressed. Therefore, sticking and breakage of the functional device when the stopper part and the movable member come into contact may be suppressed. 
     Application Example 7 
     A functional device according to this application example includes a movable member that can be displaced along a first axis, a movable electrode part extended from the movable member, a fixed electrode part provided to be opposed to the movable electrode part, a stopper part that regulates displacement of the movable member, a first fixed part and a second fixed part provided on both sides of the stopper part, a first beam part that connects the first fixed part and the movable member, and a second beam part that connects the second fixed part and the movable member, wherein the stopper part is provided to project toward the movable member, and a distance between the stopper part and the movable member is shorter than a distance between the movable electrode part and the fixed electrode part. 
     According to the functional device, when the movable member is displaced along the first axis, the movable member and the stopper part projecting toward the movable member come into contact before contact between the movable electrode part and the fixed electrode part, and thereby, contact between the fixed electrode part and the movable electrode part may be suppressed. 
     Thus, when a force of acceleration or the like is applied to the functional device and the movable member is excessively displaced, sticking between the electrode parts and breakage of the electrode parts due to contact between the fixed electrode part and the movable electrode part or the like may be suppressed. Further, the functional device that may suppress a loss of capacitance caused between the fixed electrode part and the movable electrode part and continuously measure the physical quantity of acceleration or the like may be obtained. 
     Application Example 8 
     An electronic apparatus according this application example includes any one of the above described functional devices. 
     According to the electronic apparatus, one of the above described functional devices is mounted. Even when an impact is applied to the electronic apparatus, breakage of the functional device may be suppressed and the physical quantity may be continuously detected, and thereby, the highly reliable electronic apparatus may be obtained. 
     Application Example 9 
     A moving object according this application example includes any one of the above described functional devices. 
     According to the moving object, one of the above described functional devices is mounted. Breakage of the functional device due to an impact from the moving object may be suppressed and the physical quantity may be continuously detected, and thereby, the highly reliable moving object may be obtained. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a plan view schematically showing a functional device according to a first embodiment. 
         FIG. 2  is an enlarged view showing a part of the functional device according to the first embodiment. 
         FIG. 3  is a plan view schematically showing a functional device according to a second embodiment. 
         FIG. 4  is an enlarged view showing a part of the functional device according to the second embodiment. 
         FIG. 5  is a plan view schematically showing a functional device according to a third embodiment. 
         FIG. 6  is an enlarged view showing a part of a functional device according to a fourth embodiment. 
         FIG. 7  is an enlarged view showing a part of a functional device according to a fifth embodiment. 
         FIG. 8  schematically shows a personal computer as an electronic apparatus according to a working example. 
         FIG. 9  schematically shows a cell phone as an electronic apparatus according to a working example. 
         FIG. 10  schematically shows a digital still camera as an electronic apparatus according to a working example. 
         FIG. 11  schematically shows an automobile as a moving object according to a working example. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     As below, embodiments of the invention will be explained using the drawings. Note that, in the following respective drawings, the dimensions and ratios of the respective component elements may be appropriately differentiated from the actual component elements so that the respective component elements may have sizes to the degrees that can be recognized on the drawings. 
     First Embodiment 
     A functional device according to a first embodiment will be explained using  FIGS. 1 and 2 . 
       FIG. 1  is a plan view showing an outline of the functional device according to the first embodiment.  FIG. 2  is an enlarged schematic diagram of a part shown by a dashed-dotted line A 1  in  FIG. 1 . For convenience of explanation, illustration of a lid member is omitted in  FIGS. 1 and 2 . Further, in  FIGS. 1 and 2 , an X-axis, a Y-axis, and a Z-axis are shown as three axes orthogonal to one another, and the Z-axis is an axis indicating a thickness direction in which a substrate and a device part overlap. 
     Structure of Functional Device  1   
     A functional device  1  of the embodiment shown in  FIGS. 1 and 2  includes a substrate  2 , a device part  3  provided on the substrate  2 , and a wiring part  4  electrically connected to the device part  3 . 
     In the functional device  1 , a movable part  33  forming the device part  3  can move due to acceleration or the like applied to the functional device  1 , and thereby, gaps d1 between fixed electrode parts  38 ,  39  provided on the substrate  2  and movable electrode parts  36 ,  37  provided on the movable part change. The acceleration or the like applied to the functional device  1  is measured according to the changes of the gaps d1. 
     As below, the respective parts forming the functional device  1  will be sequentially explained in detail. 
     Substrate  2   
     The substrate  2  is provided to support the device part  3 . The substrate  2  has a plate shape and a hollow part  21  is provided on a principal surface  2   a  on which the device part  3  is provided. The hollow part  21  is provided to house the movable part  33 , the movable electrode parts  36 ,  37 , and a first beam part  34 , a second beam part  35  forming the device part  3 , which will be described later, in a plan view of the substrate  2  from a perpendicular direction with respect to the principal surface  2   a . Further, the hollow part  21  has an inner bottom  21   a . The hollow part  21  forms a space in which contact between the movable part  33 , the movable electrode parts  36 ,  37 , and the first beam part  34 , the second beam part  35  forming the device part  3  and the substrate  2  is suppressed, in other words, an avoidance part. Thereby, displacement of the movable part  33  may be allowed. 
     Note that the space may be provided as an opening part penetrating the substrate  2  in the thickness direction (Z-axis direction) in place of the hollow part  21  (recessed part). Further, in the embodiment, the shape of the hollow part  21  in the plan view from the perpendicular direction with respect to the principal surface  2   a  is a rectangular shape, but not limited to that. 
     Further, groove parts  22 ,  23 ,  24  are provided on the principal surface  2   a  of the substrate  2  outside the above described hollow part  21 . The groove parts  22 ,  23 ,  24  have shapes corresponding to the wiring part  4  in the plan view from the perpendicular direction with respect to the principal surface  2   a.    
     As a material forming the substrate  2 , for example, a material of silicon, glass, or the like is preferably used. For example, when the device part  3  is formed using silicon as a major material, it is more preferable to use borosilicate glass for the substrate  2 . 
     Note that it is preferable that a difference in coefficient of linear expansion between the constituent material of the substrate  2  and the constituent material of the device part  3  is small. For example, borosilicate glass is used for the substrate  2  and silicon is used for the device part  3 , and thereby, the difference in coefficient of linear expansion between the substrate  2  and the device part  3  is smaller and distortion due to thermal expansion may be suppressed. 
     Device Part  3   
     The device part  3  includes a first fixed part  31 , a second fixed part  32 , the movable part  33 , the first beam part  34 , and the second beam part  35 . Further, the device part  3  includes the movable electrode parts  36 ,  37 , the fixed electrode parts  38 ,  39 , and stopper parts  60 . 
     In the device part  3 , the movable part  33  may be displaced in directions of an arrow a shown in  FIG. 1 , i.e., in the X-axis direction (+X-axis direction or −X-axis direction) while the first beam part  34  and the second beam part  35  are elastically deformed in response to a change of a physical quantity of acceleration, an angular velocity, or the like, for example. 
     In the device part  3 , the gap d1 between the movable electrode part  36  and the fixed electrode part  38  and the gap d1 between the movable electrode part  37  and the fixed electrode part  39  respectively change with the above described displacement. In the device part  3 , magnitudes of capacitances between the movable electrode part  36  and the fixed electrode part  38  and between the movable electrode part  37  and the fixed electrode part  39  respectively change with the above described changes of the gaps d1. 
     The functional device  1  may convert the physical quantity of acceleration, an angular velocity, or the like into electrical signals based on the changes of the capacitances. 
     First Fixed Part  31 , Second Fixed Part  32   
     The first fixed part  31  and the second fixed part  32  are respectively provided on the above described principal surface  2   a  of the substrate  2 . 
     Specifically, the first fixed part  31  is provided on the principal surface  2   a  at the side in the −X-axis direction with respect to the hollow part  21 . Further, the second fixed part  32  is provided on the principal surface  2   a  at the side in the +X-axis direction with respect to the hollow part  21 . Furthermore, the first fixed part  31  and the second fixed part  32  are respectively provided along the outer peripheral edge of the hollow part  21  in the plan view from the perpendicular direction with respect to the principal surface  2   a.    
     The first fixed part  31  has a fixed part  311  and a fixed part  312  to which the first beam part  34  is connected. The second fixed part  32  has a fixed part  321  and a fixed part  322  to which the second beam part  35  is connected. 
     Movable Part  33 , First Beam Part  34 , Second Beam Part  35   
     As shown in  FIG. 1 , the movable part  33  is provided between the first fixed part  31  and the second fixed part  32 . In the functional device  1 , the movable part  33  has a longitudinal shape extending in the X-axis directions shown in  FIG. 1 . Note that the shape of the movable part  33  is determined according to the shapes, sizes, etc. of the respective parts forming the device part  3 , but not limited to the above described shape. 
     The movable part  33  is coupled to the first fixed part  31  via the first beam part  34  and coupled to the second fixed part  32  via the second beam part  35 . More specifically, the movable part  33  is coupled to the fixed part  311  via a projecting part  33 L projecting toward the side in the −X-axis direction and a beam part  341  and coupled to the fixed part  312  via a beam part  342 . Further, a projecting part  33 R of the movable part  33  projecting toward the side in the +X-axis direction is coupled to the fixed part  321  via a beam part  351  and coupled to the fixed part  322  via a beam part  352 . 
     The first beam part  34  includes the beam part  341  and the beam part  342 . The beam part  341  and the beam part  342  respectively have shapes extending in the X-axis direction while meandering in the Y-axis direction. 
     The second beam part  35  includes the beam part  351  and the beam part  352 . The beam part  351  and the beam part  352  respectively have shapes extending in the X-axis direction while meandering in the Y-axis direction. 
     In the embodiment, the first beam part  34  and the second beam part  35  are adapted to involve elastic deformation so that the movable part  33  may be displaced (movable) in the +X-axis direction and the −X-axis direction in which the first axis shown by the arrow a extends in  FIG. 1 . 
     The first fixed part  31  includes the fixed part  311  and the fixed part  312  and is provided on the principal surface  2   a  in the −X-axis direction as the extension direction of the first axis in which the movable part  33  is displaced. To the fixed part  311  and the fixed part  312 , the beam part  341  and the beam part  342  extended from the movable part  33  are connected, respectively. 
     The second fixed part  32  includes the fixed part  321  and the fixed part  322  and is provided on the principal surface  2   a  in the +X-axis direction as the extension direction of the first axis in which the movable part  33  is displaced. To the fixed part  321  and the fixed part  322 , the beam part  351  and the beam part  352  extended from the movable part  33  are connected, respectively. 
     The first beam part  34  and the second beam part  35  are connected to the first fixed part  31  and the second fixed part  32 , and thereby, the movable part  33  is coupled (fixed) to the substrate  2 . 
     Movable Electrode Parts  36 ,  37   
     The movable electrode part  36  is extended from the movable part  33  in the +Y-axis direction as a second direction orthogonal to the X-axis direction as a first direction in which the movable part  33  is displaced. A plurality of the movable electrode parts  36  are provided to project from the movable part  33  in the +Y-axis direction in parallel to form a comb-like shape. 
     Further, the movable electrode part  37  is extended from the movable part  33  in the −Y-axis direction opposite to the +Y-axis direction in which the movable electrode part  36  is provided. A plurality of the movable electrode parts  37  are provided to project from the movable part  33  in the −Y-axis direction in parallel to form a comb-like shape. 
     As described above, the movable electrode parts  36  and the movable electrode parts  37  are provided in parallel in the X-axis direction as the first direction in which the movable part  33  is displaced (the directions of the arrow a shown in  FIG. 1 ). In other words, the plurality of movable electrode parts  36  and movable electrode parts  37  are provided in parallel along the X-axis direction as the direction in which the movable part  33  is displaced to extend to both sides in the Y-axis direction crossing the displacement direction. 
     Thereby, the capacitances generated between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37  to be described later may be changed in response to the displacement of the movable part  33 . 
     Fixed Electrode Parts  38 ,  39   
     The fixed electrode parts  38  are provided to form a comb-like shape meshing with the above described movable electrode parts  36 . 
     The fixed electrode part  38  includes a fixed electrode  381  as a first fixed electrode and a fixed electrode  382  as a second fixed electrode. The fixed electrodes  381 ,  382  are provided to respectively have the gaps d1 between the movable electrode parts  36  and themselves. Note that the explanation will be made with the reference of the fixed electrode part  38  including the fixed electrodes  381 ,  382 . 
     The fixed electrode parts  39  are provided to form a comb-like shape meshing with the movable electrode parts  37  like the above described fixed electrode part  38 . The fixed electrode part  39  includes a fixed electrode  391  as a third fixed electrode and a fixed electrode  392  as a fourth fixed electrode. The fixed electrodes  391 ,  392  are provided to respectively have the gaps d1 between the movable electrode parts  37  and themselves. Note that the explanation will be made with the reference of the fixed electrode part  39  including the fixed electrodes  391 ,  392 . 
     The fixed electrode parts  38  (fixed electrodes  381 ,  382 ) are provided at the side in the +Y-axis direction with respect to the movable part  33 . Ends of the fixed electrode parts  38  in the +Y-axis direction are connected to the wiring part  4  provided on the principal surface  2   a , and extended in the −Y-axis direction with the connected one ends as fixed ends and one ends at the opposite side to the fixed ends as free ends. 
     The fixed electrode parts  39  (fixed electrodes  391 ,  392 ) are provided at the side in the −Y-axis direction with respect to the movable part  33 . Ends of the fixed electrode parts  39  in the −Y-axis direction are connected to the wiring part  4  provided on the principal surface  2   a , and extended in the +Y-axis direction with the connected one ends as fixed ends and one ends at the opposite side to the fixed ends as free ends. 
     Stopper Parts  60   
     The stopper parts  60  that regulate the displacement of the movable part  33  are provided in the functional device  1  of the embodiment. 
     The stopper parts  60  are respectively provided on the principal surface  2   a  to be opposed to the projecting part  33 L and the projecting part  33 R extended from the movable part  33 . Specifically, the stopper part  60 L is provided to be opposed to the projecting part  33 L of the movable part  33  in the −X-axis direction in the extension direction of the first axis in which the movable part  33  is displaced. Further, the stopper part  60 R is provided to be opposed to the projecting part  33 R of the movable part  33  in the +X-axis direction in the extension direction of the first axis in which the movable part  33  is displaced. 
     Here, the arrangement etc. of the movable part  33  and the stopper parts  60  are described in detail. 
     The stopper parts  60  are provided to suppress breakage due to contact with each other between the movable electrode parts  36  and the fixed electrode parts  38  and between the movable electrode parts  37  and the fixed electrode parts  39  arranged side by side when the movable part  33  is excessively displaced. Further, the stopper parts  60  are provided to suppress sticking or short-circuit caused by the contact with each other between the movable electrode parts  36  and the fixed electrode parts  38  and between the movable electrode parts  37  and the fixed electrode parts  39 . 
     In the movable part  33 , the projecting part  33 L is extended between the beam part  341  and the beam part  342  and toward the stopper part  60 L provided in the direction in which the first axis extends (−X-axis direction) as shown in  FIG. 1 . The extended projecting part  33 L is provided to have a gap d2 between the projecting part  33 L and the stopper part  60 L. 
     Further, in the movable part  33 , the projecting part  33 R is extended between the beam part  351  and the beam part  352  and toward the stopper part  60 R provided in the direction in which the first axis extends (+X-axis direction) as shown in  FIG. 1 . The extended projecting part  33 R is provided to have a gap d2 between the projecting part  33 R and the stopper part  60 R. 
     For the functional device  1  in the first embodiment, when the movable part  33  is excessively displaced, contact between the stopper parts  60  and the movable part  33  is desired before contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37 . Thus, in the functional device  1 , the movable part  33  is provided so that the gaps d2 between the movable part  33  (projecting part  33 L, projecting part  33 R) and the stopper parts  60  may be narrower than the gaps d1 between the movable electrode parts  36 ,  37  and the fixed electrode parts  38 ,  39 . That is, the movable part  33  (projecting part  33 L, projecting part  33 R) is extended toward the stopper parts  60  so that the width relationship between the gaps d1 and the gaps d2 may satisfy gap d1&gt;gap d2. 
     Further, in the functional device  1 , when the movable part  33  is displaced in the rotation direction around the point P shown in  FIG. 1 , the projecting part  33 L comes into contact with the first beam part  34  (beam part  341 , beam part  342 ), and thereby, displacement in the rotation direction generated in the movable part  33  may be regulated. Furthermore, the projecting part  33 R comes into contact with the second beam part  35  (beam part  351 , beam part  352 ), and thereby, displacement in the rotation direction generated in the movable part  33  may be regulated. 
     Further, in the functional device  1 , the first beam part  34  (beam part  341 , beam part  342 ) and the second beam part  35  (beam part  351 , beam part  352 ) are coupled to the first, second fixed parts  31 ,  32  with gaps, and thereby, the movable part  33  is fixed. Therefore, the displacement of the movable part  33  in the rotation direction around the point P shown in  FIG. 1  may be suppressed. 
     Thereby, the functional device  1  may suppress excessive displacement of the movable part  33  by the contact between the movable part  33  and the stopper parts  60  before the contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37 . Further, when the movable part  33  is displaced in an in-plane rotation direction, the displacement in the rotation direction may be regulated by the contact between the projecting part  33 L and the projecting part  33 R, and the first beam part  34  and the second beam part  35 . Furthermore, the movable part  33  may suppress the displacement in the rotation direction generated in the movable part  33  by urging forces of the beam part  341  and the beam part  342  extended from the projecting part  33 L and the beam part  351  and the beam part  352  extended from the projecting part  33 R. 
     In addition, it is preferable that the stopper parts  60  are at the same potential (equal potential) with the movable part  33 . 
     The stopper parts  60  are at the equal potential to the movable part  33 , and thereby, when coming into contact with the movable part  33 , no electrostatic force acts thereon and sticking may be suppressed. Further, the stopper parts are at the equal potential to the movable part  33 , and thereby, fluctuations and losses due to ground faults of capacitances caused between the movable electrode parts  36 ,  37  and the fixed electrode parts  38 ,  39  may be suppressed. 
     For the purpose, the stopper parts  60  are electrically connected to the movable part  33  via the first fixed part  31  and the first beam part  34 , and the second fixed part  32  and the second beam part  35  by wiring (not shown). 
     As a material forming the device part  3 , not particularly limited, but any material having conductivity may be used. For example, a silicon substrate is preferably used for the material forming the device part  3 . Using the silicon substrate, the first fixed part  31 , the second fixed part  32 , the movable part  33 , the first beam part  34  and the second beam part  35 , the movable electrode parts  36 ,  37 , the fixed electrode parts  38 ,  39 , and the stopper parts  60  may be integrally formed using a typical semiconductor device manufacturing technology. 
     Wiring Part  4   
     The wiring part  4  is provided on the principal surface  2   a  of the substrate  2 . The wiring part  4  includes wires  41 ,  42 ,  43  and electrodes  44 ,  45 ,  46 . 
     The wire  41  is provided on the principal surface  2   a  between the hollow part  21  and the outer peripheral edge of the substrate  2  along the outer periphery of the hollow part  21 . One end of the wire  41  is connected to the electrode  44 . Further, the other end of the wire  41  different from the one end connected to the electrode  44  is electrically connected to the fixed electrodes  381  as the first fixed electrodes and the fixed electrodes  391  as the third fixed electrodes of the plurality of fixed electrode parts  38 ,  39 . 
     The wire  42  is provided on the principal surface  2   a  between the hollow part  21  and the outer peripheral edge of the substrate  2  along the wire  41 . One end of the wire  42  is connected to the electrode  45 . 
     Further, the other end of the wire  42  different from the one end connected to the electrode  45  is electrically connected to the fixed electrodes  382  as the second fixed electrodes and the fixed electrodes  392  as the fourth fixed electrodes of the plurality of fixed electrode parts  38 ,  39 . 
     The wire  43  is connected to the first fixed part  31  (fixed part  311 , fixed part  312 ) and the electrode  46  is connected to the other end of the wire  43  different from the one end connected to the first fixed part  31 . 
     Further, the wire  41  is provided within the groove  22  (recessed part) provided on the principal surface  2   a . The wire  42  is provided within the groove  23  (recessed part) provided on the principal surface  2   a . The wire  43  is provided within the groove  24  (recessed part) provided on the principal surface  2   a.    
     As materials forming the wires  41  to  43 , not particularly limited, but any materials having conductivity may be used. For example, the materials include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), gold (Au), platinum (Pt), silver (Ag), copper (Cu), aluminum (Al), or alloys containing them, and one of them or a combination of some of them may be used. 
     Further, as materials forming the electrodes  44  to  46 , like the above described wires  41  to  43 , not particularly limited, but any materials having conductivity may be used. 
     By the wire  41  and the electrode  44 , and the wire  43  and the electrode  46 , changes of the capacitances between the first fixed electrodes (fixed electrodes  381 ) and the movable electrode parts  36  and the capacitances between the third fixed electrodes (fixed electrodes  391 ) and the movable electrode parts  37  may be output via the wire  41 . 
     Further, by the wire  42  and the electrode  45 , and the wire  43  and the electrode  46 , changes of the capacitances between the second fixed electrodes (fixed electrodes  382 ) and the movable electrode parts  36  and the capacitances between the fourth fixed electrodes (fixed electrodes  392 ) and the movable electrode parts  37  may be output via the wire  42 . 
     Lid Member 
     The lid member (not shown) is provided for protection of the above described device part  3 . 
     The lid member has a plate shape and a cavity (not shown) is provided on one surface (lower surface) thereof. The cavity is formed to allow the displacement of the movable part  33 . 
     Further, the part outer than the cavity on the lower surface of the lid member is connected to the above described principal surface  2   a  (substrate  2 ). 
     As a connecting method for the lid member and the substrate  2 , not particularly limited, but, for example, a connecting method using an adhesive, an anodic bonding (connecting) method, or the like may be used. 
     Further, as a material forming the lid member, not particularly limited, but a material suitable for the connecting method may be used. For example, a silicon material may be used for the connection using an adhesive and a glass material or the like may be used for the connection using the anodic bonding method. 
     According to the above described first embodiment, the following advantages may be obtained. 
     According to the functional device  1 , when the movable part  33  is displaced in the direction in which the first axis extends, the movable part  33  and the stopper parts  60  come into contact before contact between the movable electrode parts  36 ,  37  and the fixed electrode parts  38 ,  39 , and thereby, the contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37  may be suppressed. Further, when the displacement in the rotation direction around the point P in the plan view from the perpendicular direction with respect to the movable part  33  is generated in the movable part  33 , the projecting part  33 L and the projecting part  33 R come into contact with the first beam part  34  and the second beam part  35 , and thereby, the displacement may be regulated. 
     Thus, when a force of acceleration or the like is applied to the functional device  1  and the movable part  33  is excessively displaced, by the contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37  or the like, sticking and breakage of the electrode parts may be suppressed. Further, the functional device  1  that may suppress losses of the capacitances generated between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37  and may continuously measure the physical quantity of acceleration or the like may be obtained. 
     Second Embodiment 
     A functional device according to the second embodiment will be explained using  FIGS. 3 and 4 . 
       FIG. 3  is a plan view showing an outline of the functional device according to the second embodiment.  FIG. 4  is an enlarged schematic diagram of a part shown by a dashed-dotted line A 2  in  FIG. 3 . For convenience of explanation, illustration of a lid member is omitted in  FIGS. 3 and 4 . Further, in  FIGS. 3 and 4 , an X-axis, a Y-axis, and a Z-axis are shown as three axes orthogonal to one another, and the Z-axis is an axis indicating a thickness direction in which a substrate and a device part overlap. 
     A functional device  1   a  according to the second embodiment is different from the functional device  1  explained in the first embodiment in that the stopper parts  60  are extended toward the movable part  33 . 
     The other configurations etc. are nearly the same as those of the above described functional device  1  in the first embodiment, and the functional device  1   a  will be explained with the same configurations having the same signs and numerals and their explanation will be partially omitted. 
     Structure of Functional Device  1   a    
     The functional device  1   a  of the embodiment shown in  FIGS. 3 and 4  includes a substrate  2 , a device part  3  provided on the substrate  2 , and a wiring part  4  electrically connected to the device part  3  like the above described functional device  1  in the first embodiment. 
     In the functional device  1   a , a movable part  33  forming the device part  3  can move due to acceleration or the like applied to the functional device  1   a , and thereby, gaps d1 between fixed electrode parts  38 ,  39  provided on the substrate  2  and movable electrode parts  36 ,  37  provided on the movable part  33  change. The acceleration or the like applied to the functional device  1   a  is measured according to the changes of the gaps d1. 
     Movable Part  33   
     In the functional device  1   a , the movable part  33  is extended in the X-axis direction as an extension direction of a first axis in which the movable part  33  is displaced. A first beam part  34  is connected to an end part  33 TL of the movable part  33  at the side in the −X-axis direction as the direction in which the first axis extends. Further, a second beam part  35  is connected to an end part  33 TR of the movable part  33  at the side in the +X-axis direction as the direction in which the first axis extends. 
     The movable part  33  is coupled to a first fixed part  31  via a first beam part  34  and coupled to a second fixed part  32  via a second beam part  35 . More specifically, the end part  33 TL of the movable part  33  at the side in the −X-axis direction is coupled to a fixed part  311  via a beam part  341  and coupled to a fixed part  312  via a beam part  342 . Further, the end part  33 TR of the movable part  33  at the side in the +X-axis direction is connected to a fixed part  321  via a beam part  351  and connected to a fixed part  322  via a beam part  352 . 
     Stopper Parts  60   
     The stopper parts  60  that regulate the displacement of the movable part  33  are provided in the functional device  1   a  of the embodiment. Further, projecting parts  62  are extended from the stopper parts  60  toward the movable part  33 . 
     The stopper parts  60  are respectively provided on the principal surface  2   a  to be opposed to the end parts  33 TL,  33 TR of the movable part  33 . Specifically, a stopper part  60 L and a projecting part  62 L are provided to be opposed to the end part  33 TL of the movable part  33  in the −X-axis direction as the extension direction of the first axis in which the movable part  33  is displaced. The projecting part  62 L extended from the stopper part  60 L is extended toward the end part  33 TL of the movable part  33  between the beam part  341  and the beam part  342 . Further, a stopper part  60 R and a projecting part  62 R are provided to be opposed to the end part  33 TR of the movable part  33  in the +X-axis direction as the extension direction of the first axis in which the movable part  33  is displaced. The projecting part  62 R extended from the stopper part  60 R is extended toward the end part  33 TR of the movable part  33  between the beam part  351  and the beam part  352 . 
     Here, the arrangement etc. of the movable part  33  and the stopper parts  60  are described in detail. 
     The stopper parts  60  are provided, like in the functional device  1 , to suppress breakage of the movable electrode parts  36  and the fixed electrode parts  38 , and the movable electrode parts  37  and the fixed electrode parts  39  arranged side by side due to contact with each other when the movable part  33  is excessively displaced. 
     Further, the stopper parts  60  are provided to suppress sticking or short-circuit caused by the contact with each other between the movable electrode parts  36  and the fixed electrode parts  38  and between the movable electrode parts  37  and the fixed electrode parts  39 . 
     For the functional device  1   a  in the second embodiment, when excessive displacement is applied to the movable part  33 , contact between the stopper parts  60  and the movable part  33  is desired before contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37 . 
     Thus, the stopper parts  60  are provided so that gaps d3 between the movable part  33  (end parts  33 TL,  33 TR) and the stopper parts  60  (projecting parts  62 L,  62 R) may be narrower than the gaps d1 between the movable electrode parts  36 ,  37  and the fixed electrode parts  38 ,  39 . That is, the stopper parts  60  (projecting parts  62 ) are extended toward the movable part  33  so that the width relationship between the gaps d1 and the gaps d3 may satisfy gap d1&gt;gap d3. 
     Further, in the functional device  1   a , when the movable part  33  is displaced in the rotation direction around the point P shown in  FIG. 3 , for example, the stopper part  60 L (projecting part  62 L) comes into contact with the first beam part  34  (beam part  341 , beam part  342 ), and thereby, displacement in the rotation direction generated in the movable part  33  may be regulated. Furthermore, the stopper part  60 R (projecting part  62 R) comes into contact with the second beam part  35  (beam part  351 , beam part  352 ), and thereby, displacement in the rotation direction generated in the movable part  33  may be regulated. 
     Thereby, the functional device  1   a  may suppress excessive displacement of the movable part  33  by the contact between the movable part  33  and the stopper parts  60  before the contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37 . Further, when the movable part  33  rotates in the rotation direction, the displacement in the rotation direction may be regulated by the contact between the stopper parts  60 L,  60 R (projecting parts  62 L,  62 R), and the first beam part  34  and the second beam part  35 . Furthermore, the movable part  33  may suppress the displacement in the rotation direction generated in the movable part  33  by urging forces of the beam part  341  and the beam part  342  extended from the end part  33 TL and the beam part  351  and the beam part  352  extended from the end part  33 TR. 
     In the functional device  1   a , the other configurations are the same as those of the above described functional device  1  in the first embodiment, and their explanation will be omitted. 
     According to the above described second embodiment, the following advantages may be obtained. 
     According to the functional device  1   a , when the movable part  33  is displaced in the first direction, the movable part  33  and the stopper parts  60  come into contact before contact between the movable electrode parts  36 ,  37  and the fixed electrode parts  38 ,  39 , and thereby, the contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37  may be suppressed. Further, when displacement in the rotation direction around the point P in the plan view from the perpendicular direction with respect to the movable part  33  is generated in the movable part  33 , the stopper parts  60  come into contact with the first beam part  34  and the second beam part  35 , and thereby, the displacement may be regulated. 
     Thus, when a force of acceleration or the like is applied to the functional device  1   a  and the movable part  33  is excessively displaced, by the contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37  or the like, sticking and breakage of the electrode parts may be suppressed. Further, the functional device  1   a  that may suppress losses of the capacitances generated between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37  and may continuously measure the physical quantity of acceleration or the like may be obtained. 
     Third Embodiment 
     A functional device according to the third embodiment will be explained using  FIG. 5 . 
       FIG. 5  is a plan view showing an outline of the functional device according to the third embodiment. For convenience of explanation, illustration of a lid member is omitted in  FIG. 5 . Further, in  FIG. 5 , an X-axis, a Y-axis, and a Z-axis are shown as three axes orthogonal to one another, and the Z-axis is an axis indicating a thickness direction in which a substrate and a device part overlap. 
     A functional device  1   b  according to the third embodiment is different from the functional device  1  explained in the first embodiment in that fixed parts  131 ,  132  and stopper parts  160  are integrally provided. 
     The other configurations etc. are nearly the same as those of the above described functional device  1  in the first embodiment, and the functional device  1   b  will be explained with the same configurations having the same signs and numerals and their explanation will be partially omitted. 
     Structure of Functional Device  1   b    
     The functional device  1   b  of the embodiment shown in  FIG. 5  includes a substrate  2 , a device part  3  provided on the substrate  2 , and a wiring part  4  electrically connected to the device part  3  like the above described functional device  1  in the first embodiment. 
     In the functional device  1   b , a movable part  33  forming the device part  3  can move due to acceleration or the like applied to the functional device  1   b , and thereby, gaps d1 between fixed electrode parts  38 ,  39  provided on the substrate  2  and movable electrode parts  36 ,  37  provided on the movable part  33  change. The acceleration or the like applied to the functional device  1   b  is measured according to the changes of the gaps d1. 
     Movable Part  33   
     In the functional device  1   b , the movable part  33  is extended in the X-axis direction as an extension direction of a first axis in which the movable part  33  is displaced. A first beam part  34  is connected to a projecting part  33 L provided in the −X-axis direction as the direction in which the first axis extends. Further, a second beam part  35  is connected to a projecting part  33 R provided in the +X-axis direction as the direction in which the first axis extends. 
     The projecting part  33 L (movable part  33 ) is connected to one end of the first beam part  34  and the other end of the first beam part  34  is connected to a fixed part  131 . Further, the projecting part  33 R (movable part  33 ) is connected to one end of the second beam part  35  and the other end of the second beam part  35  is connected to a fixed part  132 . Thereby, the movable part  33  is fixed to the substrate  2 . 
     More specifically, the movable part  33  is coupled to the fixed part  131  via the projecting part  33 L projecting to the side in the −X-axis direction. Further, the movable part  33  is coupled to the fixed part  132  via the projecting part  33 R projecting to the side in the +X-axis direction. 
     Fixed Parts  131 ,  132 , Stopper Parts  160   
     As shown in  FIG. 5 , the fixed part  131  is provided integrally with a stopper part  160 L. Further, the fixed part  132  is provided integrally with a stopper part  160 R. 
     The fixed part  131  is provided on the principal surface  2   a  in the −X-axis direction as one direction of the extension directions of the first axis in which the movable part  33  is displaced. To the fixed part  311 , beam parts  341 ,  342  extended from the projecting part  33 L are connected. The fixed part  132  is provided on the principal surface  2   a  in the +X-axis direction as one direction of the extension directions of the first axis in which the movable part  33  is displaced. To the fixed part  132 , beam parts  351 ,  352  extended from the projecting part  33 R are connected. 
     The first beam part  34  and the second beam part  35  are connected to the fixed parts  131 ,  132 , respectively, and thereby, the movable part  33  may be fixed to the substrate  2 . 
     Here, the arrangement etc. of the movable part  33  and the stopper parts  160  are described in detail. 
     The stopper parts  160  are provided to suppress breakage due to contact with each other between the movable electrode parts  36  and the fixed electrode parts  38  and between the movable electrode parts  37  and the fixed electrode parts  39  arranged side by side when the movable part  33  is excessively displaced. Further, the stopper parts  160  are provided to suppress sticking or short-circuit caused by the contact with each other between the movable electrode parts  36  and the fixed electrode parts  38  and between the movable electrode parts  37  and the fixed electrode parts  39 . 
     In the movable part  33 , the projecting part  33 L is extended between a beam part  341  and a beam part  342  and toward the stopper part  160 L provided in the direction in which the first axis extends (−X-axis direction) as shown in  FIG. 5 . The movable part  33  is provided to have a gap d2 between the extended projecting part  33 L and the stopper part  160 L. Further, in the movable part  33 , the projecting part  33 R is extended between a beam part  351  and a beam part  352  and toward the stopper part  160 R provided in the direction in which the first axis extends (+X-axis direction) as shown in  FIG. 5 . The movable part  33  is provided to have a gap d2 between the extended projecting part  33 R and the stopper part  160 R. 
     For the functional device  1   b  in the third embodiment, when excessive displacement is applied to the movable part  33 , contact between the stopper parts  160  and the movable part  33  is desired before contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37 . 
     Thus, the movable part  33  is provided so that the gaps d2 between the movable part  33  (projecting part  33 L, projecting part  33 R) and the stopper parts  160  may be narrower than the gaps d1 between the movable electrode parts  36 ,  37  and the fixed electrode parts  38 ,  39 . That is, the movable part  33  (projecting part  33 L, projecting part  33 R) is extended toward the stopper parts  160  so that the width relationship between the gaps d1 and the gaps d2 may satisfy gap d1&gt;gap d2. 
     Thereby, in the functional device  1   b , the stopper parts  160  and the movable part  33  come into contact before contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37 , and excessive displacement of the movable part  33  may be regulated. Further, when the movable part  33  is displaced in the rotation direction around the point P, the projecting parts  33 L,  33 R come into contact with the first beam part  34  and the second beam part  35 , and thereby, displacement in the rotation direction may be regulated. 
     In the functional device  1   b , the other configurations are the same as those of the above described functional device  1  in the first embodiment, and their explanation will be omitted. 
     According to the above described third embodiment, the following advantages may be obtained. 
     According to the functional device  1   b , when the movable part  33  is displaced in the first direction, the movable part  33  and the stopper parts  160  come into contact before contact between the movable electrode parts  36 ,  37  and the fixed electrode parts  38 ,  39 , and thereby, the contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37  may be suppressed. Further, when displacement in the rotation direction around the point P in the plan view from the perpendicular direction with respect to the movable part  33  is generated in the movable part  33 , the projecting parts  33 L,  33 R of the movable part  33  come into contact with the first beam part  34  and the second beam part  35 , and thereby, the displacement may be regulated. 
     Thus, when a force of acceleration or the like is applied to the functional device  1   b  and the movable part  33  is excessively displaced, by the contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37  or the like, sticking and breakage of the electrode parts may be suppressed. Further, the functional device  1   b  that may suppress losses of the capacitances generated between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37  and may continuously measure the physical quantity of acceleration or the like may be obtained. 
     Fourth Embodiment 
     A functional device according to the fourth embodiment will be explained using  FIG. 6 . 
       FIG. 6  is an enlarged schematic diagram showing a part of the functional device according to the fourth embodiment and corresponds to the part of the dashed-dotted line A 1  in  FIG. 1  showing the above described functional device  1  in the first embodiment. In  FIG. 6 , an X-axis, a Y-axis, and a Z-axis are shown as three axes orthogonal to one another, and the Z-axis is an axis indicating a thickness direction in which a substrate and a device part overlap. 
     A functional device  1   c  according to the fourth embodiment is different from the functional device  1  explained in the first embodiment in that projections  200  are provided on the projecting parts  33 L and  33 R of the movable part  33 . 
     The other configurations etc. are nearly the same as those of the above described functional device  1  in the first embodiment, and the functional device  1   c  will be explained with the same configurations having the same signs and numerals and their explanation will be partially omitted. 
     Structure of Functional Device  1   c    
     The functional device  1   c  of the embodiment shown in  FIG. 6  includes a substrate  2 , a device part  3  provided on the substrate  2 , and a wiring part  4  electrically connected to the device part  3  like the above described functional device  1  in the first embodiment. 
     In the functional device  1   c , a movable part  33  forming the device part  3  can move due to acceleration or the like applied to the functional device  1   c , and thereby, gaps d1 between fixed electrode parts  38 ,  39  provided on the substrate  2  and movable electrode parts  36 ,  37  provided on the movable part  33  change. The acceleration or the like applied to the functional device  1   c  is measured according to the changes of the gaps d1. 
     Movable Part  33   
     In the functional device  1   c , the movable part  33  is extended in the X-axis direction as a first direction in which the movable part  33  is displaced. A first beam part  34  is connected to a projecting part  33 L provided in the −X-axis direction as the direction in which a first axis extends. Further, a second beam part  35  is connected to a projecting part  33 R provided in the +X-axis direction as the direction in which the first axis extends. 
     Furthermore, the projections  200  are provided on the projecting part  33 L of the movable part  33 . Projections  210  are provided on an end surface  34 L of the projecting part  33 L opposed to the stopper part  60 L and projections  220  are provided on an end surface  35 L of the projecting part  33 L in the direction crossing the end surface  34 L. 
     In addition, though not illustrated, the projections  200  are similarly provided on the projecting part  33 R opposite to the projecting part  33 L. 
     Stopper Parts  60   
     The stopper parts  60  that regulate the displacement of the movable part  33  are provided in the functional device  1   c  of the embodiment like in the functional device  1 . 
     The stopper parts  60  are respectively provided on the principal surface  2   a  to be opposed to the projecting parts  33 L,  33 R of the movable part  33 . 
     Here, the arrangement etc. of the movable part  33  and the stopper parts  60  are described in detail. 
     The stopper parts  60  are provided to suppress breakage due to contact with each other between the movable electrode parts  36  and the fixed electrode parts  38  and between the movable electrode parts  37  and the fixed electrode parts  39  arranged side by side when the movable part  33  is excessively displaced. Further, the stopper parts  60  are provided to suppress sticking or short-circuit caused by the contact with each other between the movable electrode parts  36  and the fixed electrode parts  38  and between the movable electrode parts  37  and the fixed electrode parts  39 . 
     In the movable part  33 , the projecting part  33 L is extended between the beam part  341  and the beam part  342  and toward the stopper part  60 L provided in the direction in which the first axis extends (−X-axis direction) as shown in the partially enlarged view in  FIG. 6 . The movable part  33  is provided to have a gap d21 between the projections  210  provided on the end surface  34 L of the extended projecting part  33 L and the stopper part  60 L. Further, in the movable part  33 , the projecting part  33 R (not shown) is extended between the beam part  351  and the beam part  352  and toward the stopper part  60 R (not shown) provided in the direction in which the first axis extends (+X-axis direction). The movable part  33  is provided to have a gap d21 between the projections  210  provided on the end surface  34 R (not shown) of the extended projecting part  33 R and the stopper part  60 R. 
     For the functional device  1   c  in the fourth embodiment, when excessive displacement is applied to the movable part  33 , contact between the stopper parts  60  and the projections  200  of the movable part  33  is desired before contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37 . 
     Thus, the movable part  33  is provided so that the gaps d21 between the projections  200  provided on the movable part  33  and the stopper parts  60  may be narrower than the gaps d1 between the movable electrode parts  36 ,  37  and the fixed electrode parts  38 ,  39 . That is, the projections  200  are provided on the movable part  33  (projecting part  33 L, projecting part  33 R) so that the width relationship between the gaps d1 and the gaps d21 may satisfy gap d1&gt;gap d21. 
     Thereby, in the functional device  1   c , the projections  210  provided on the movable part  33  and the stopper parts  60  come into contact before contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37 , and excessive displacement of the movable part  33  may be suppressed. 
     Further, when the movable part  33  is displaced in a second direction crossing the direction in which the first axis extends, the first beam part  34  and the second beam part  35  may be brought into point contact because the projections  220  are provided on the end surfaces  35 L,  35 R of the movable part  33 . Therefore, sticking and breakage due to contact between the movable part  33  and the first beam part  34 , the second beam part  35  may be suppressed. 
     In the functional device  1   c , the other configurations are the same as those of the above described functional device  1  in the first embodiment, and their explanation will be omitted. 
     According to the above described fourth embodiment, the following advantages may be obtained. 
     According to the functional device  1   c , the contact area when the stopper parts  60  and the movable part  33  come into contact may be made smaller compared to those of the above described functional devices  1 ,  1   a ,  1   b.    
     Further, the projections  220  are provided on the end surfaces  35 L,  35 R of the projecting parts  33 L,  33 R opposed to the first beam part  34 , the second beam part  35 , and thereby, the contact area between the first beam part  34 , the second beam part  35  and the projecting parts  33 L,  33 R may be made smaller. Therefore, sticking when the movable part  33  and the stopper parts  60  or the movable part  33  and the first beam part  34 , the second beam part  35  come into contact may be suppressed. Further, the impact when the movable part  33  and the stopper parts  60  or the movable part  33  and the first beam part  34 , the second beam part  35  come into contact may be reduced. Thus, breakage of the functional device  1   c  when the movable part  33  and the stopper parts  60  or the movable part  33  and the first beam part  34 , the second beam part  35  come into contact may be suppressed. 
     Fifth Embodiment 
     A functional device according to the fifth embodiment will be explained using  FIG. 7 . 
       FIG. 7  is an enlarged schematic diagram showing a part of the functional device according to the fifth embodiment and corresponds to the part of the dashed-dotted line A 2  in  FIG. 3  showing the above described functional device  1   a  in the second embodiment. In  FIG. 7 , an X-axis, a Y-axis, and a Z-axis are shown as three axes orthogonal to one another, and the Z-axis is an axis indicating a thickness direction in which a substrate and a device part overlap. 
     A functional device  1   d  according to the fifth embodiment is different from the functional device  1   a  explained in the second embodiment in that projections  200  are provided on the stopper parts  60 . 
     The other configurations etc. are nearly the same as those of the above described functional device  1   a  in the second embodiment, and the functional device  1   d  will be explained with the same configurations having the same signs and numerals and their explanation will be partially omitted. 
     Structure of Functional Device  1   d    
     The functional device  1   d  of the embodiment shown in  FIG. 7  includes a substrate  2 , a device part  3  provided on the substrate  2 , and a wiring part  4  electrically connected to the device part  3  like the above described functional device  1  in the first embodiment. 
     In the functional device  1   d , a movable part  33  forming the device part  3  can move due to acceleration or the like applied to the functional device  1   d , and thereby, gaps d1 between fixed electrode parts  38 ,  39  provided on the substrate  2  and movable electrode parts  36 ,  37  provided on the movable part  33  change. The acceleration or the like applied to the functional device  1   d  is measured according to the changes of the gaps d1. 
     Movable Part  33   
     In the functional device  1   d , the movable part  33  is extended in the X-axis direction as a first direction in which the movable part  33  is displaced. A first beam part  34  is connected to a projecting part  33 L in the −X-axis direction as the first direction. Further, a second beam part  35  is connected to a projecting part  33 R (not shown) in the +X-axis direction as the first direction. 
     Stopper Parts  60   
     The stopper parts  60  that regulate the displacement of the movable part  33  are provided in the functional device  1   d  of the embodiment like in the functional device  1   a . Further, projecting parts  62  are extended from the stopper parts  60  toward the movable part  33 . 
     The stopper parts  60  include a stopper part  60 L provided on a principal surface  2   a  to be opposed to an end part  33 TL of the movable part  33  and a stopper part  60 R (not shown) provided on the principal surface  2   a  to be opposed to an end part  33 TR (not shown) of the movable part  33 . As shown in  FIG. 7 , the stopper part  60 L and a projecting part  62 L from the stopper part  60 L are extended to be opposed to the end part  33 TL of the movable part  33  in the −X-axis direction. Like the stopper part  60 L and the projecting part  62 L, the stopper part  60 R and a projecting part  62 R from the stopper part  60 R are extended to be opposed to the end part  33 TR of the movable part  33  in the +X-axis direction. 
     The projections  200  are provided on the projecting part  62 L (stopper part  60 L) and the projecting part  62 R (stopper part  60 R) (not shown). In the projecting part  62 L, projections  210  are provided on an end surface  63 L opposed to the movable part  33  and projections  220  are provided on an end surface  64 L of the projecting part  62 L in the direction crossing the end surface  63 L. 
     Further, also, in the projecting part  62 R (stopper part  60 R) (not shown) opposite to the projecting part  62 L (stopper part  60 L), the projections  210  (not shown) are provided on an end surface  63 R (not shown) opposed to the movable part  33  and the projections  220  (not shown) are provided on an end surface  64 R (not shown) of the stopper part  60 R in the direction crossing the end surface  63 R. 
     Here, the arrangement etc. of the movable part  33  and the stopper parts  60  are described in detail. 
     The stopper parts  60  are provided to suppress breakage due to contact with each other between the movable electrode parts  36  and the fixed electrode parts  38  and between the movable electrode parts  37  and the fixed electrode parts  39  arranged side by side when the movable part  33  is excessively displaced. Further, the stopper parts  60  are provided to suppress sticking or short-circuit caused by the contact with each other between the movable electrode parts  36  and the fixed electrode parts  38  and between the movable electrode parts  37  and the fixed electrode parts  39 . 
     The stopper part  60 L is extended between a beam part  341  and a beam part  342  and toward the movable part  33  provided in the direction in which the first axis extends (+X-axis direction) as shown in  FIG. 7 . In the stopper part  60 L, the projections  210  are provided on the end surface  63 L of the extended projecting part  62 L. The projecting part  62 L is provided to have a gap d31 between the projections  210  and the movable part  33 . Further, the stopper part  60 R is extended between a beam part  351  and a beam part  352  and toward the movable part  33  provided in the direction in which the first axis extends (−X-axis direction) like the stopper part  60 L (see  FIG. 3 ). In the stopper part  60 R, the projections  210  are provided on the end surface  63 R of the extended projecting part  62 R. The projecting part  62 R is provided to have the gap d31 between the projections  210  and the movable part  33 . 
     For the functional device  1   d  in the fifth embodiment, when excessive displacement is applied to the movable part  33 , contact between the movable part  33  and the projections  210  provided on the projecting parts  62  extended from the stopper parts  60  is desired before contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37 . 
     Thus, the stopper parts  60  are provided so that the gaps d31 between the movable part  33  and the projections  210  provided on the projecting parts  62  may be narrower than the gaps d1 between the movable electrode parts  36 ,  37  and the fixed electrode parts  38 ,  39 . That is, the projections  210  are provided on the projecting parts  62  ( 62 R,  62 L) extended from the stopper parts  60  ( 60 L,  60 R) so that the width relationship between the gaps d1 and the gaps d3 may satisfy gap d1&gt;gap d31. 
     Thereby, the functional device  1   d  may suppress excessive displacement of the movable part  33  by the contact between the movable part  33  and the projections  210  provided on the stopper parts  60  before the contact between the fixed electrode parts  38 ,  39  and the movable electrode parts  36 ,  37 . 
     Further, when the movable part  33  is displaced in a second direction crossing the first direction, the stopper parts  60  (projecting parts  62 ) and the first beam part  34 , the second beam part  35  may be brought into point contact because the projections  220  are provided on the end surfaces  64 L,  64 R of the projecting parts  62 L,  62 R. Therefore, breakage due to contact between the stopper parts  60  and the first beam part  34 , the second beam part  35  may be suppressed. 
     In the functional device  1   d , the other configurations are the same as those of the above described functional device  1  in the first embodiment, and their explanation will be omitted. 
     According to the above described fifth embodiment, the following advantages may be obtained. 
     According to the functional device  1   d , the contact area when the stopper parts  60  and the movable part  33  come into contact may be made smaller compared to those of the above described functional devices  1 ,  1   a ,  1   b.    
     Further, the projections  220  are provided on the end surfaces  64 L,  64 R of the stopper parts  60 L,  60 R opposed to the first beam part  34 , the second beam part  35 , and thereby, the contact area between the first beam part  34 , the second beam part  35  and the stopper parts  60 L,  60 R may be made smaller. Therefore, sticking when the movable part  33  and the stopper parts  60 L,  60 R come into contact or the first beam part  34 , the second beam part  35  and the stopper parts  60 L,  60 R come into contact may be suppressed. Further, the impact when the movable part  33  and the stopper parts  60 L,  60 R come into contact or the first beam part  34 , the second beam part  35  and the stopper parts  60 L,  60 R come into contact may be reduced. Thus, breakage of the functional device  1   d  when the movable part  33  and the stopper parts  60 L,  60 R come into contact or the first beam part  34 , the second beam part  35  and the stopper parts  60 L,  60 R come into contact may be suppressed. 
     Note that, in the above described functional devices  1 ,  1   a ,  1   b ,  1   c ,  1   d  in the first embodiment to the fifth embodiment, the forms in which the stopper parts  60 ,  160  are provided in line symmetry in both extension directions of the first axis of the X-axis directions (the directions of the arrow a shown in  FIGS. 1 ,  3 ,  5 ) in which the movable part  33  is displaced have been explained. However, the forms are not limited to those as long as the stopper parts  60 ,  160  are provided in one direction of the X-axis directions in which the movable part  33  is displaced. Further, the explanation of the functional devices that measure physical quantities including acceleration and an angular velocity has been made as above, however, the invention may be applied to an MEMS vibrator or the like having the similar configuration. 
     Working Examples 
     Working examples to which one of the functional devices  1 ,  1   a ,  1   b ,  1   c ,  1   d  (hereinafter, collectively explained as the functional device  1 ) according to one embodiment of the invention is applied will be explained with reference to  FIGS. 8 to 11 . 
     Electronic Apparatuses 
     Electronic apparatuses to which the functional device according to one embodiment of the invention is applied will be explained with reference to  FIGS. 8 to 10 . 
       FIG. 8  is a perspective view showing an outline of a configuration of a laptop (or mobile) personal computer as an electronic apparatus including the functional device according to one embodiment of the invention. In the drawing, a laptop personal computer  1100  includes a main body unit  1104  having a keyboard  1102  and a display unit  1106  having a display part  1008 , and the display unit  1106  is rotatably supported via a hinge structure part with respect to the main body unit  1104 . The lap top personal computer  1100  contains the functional device  1  that functions as an acceleration sensor or the like for sensing acceleration or the like applied to the laptop personal computer  1100  and displaying the acceleration or the like on the display unit  1106 . In the functional device  1 , breakage due to a vibration by the operation of the laptop personal computer  1100  and an impact with drop may be suppressed, and the physical quantity may be continuously detected. Thus, the reliable laptop personal computer  1100  may be obtained. 
       FIG. 9  is a perspective view showing an outline of a configuration of a cell phone (including a PHS) as the electronic apparatus including the functional device according to one embodiment of the invention. In the drawing, a cell phone  1200  includes a plurality of operation buttons  1202 , an ear piece  1204 , and a mouthpiece  1206 , and a display part  1208  is provided between the operation buttons  1202  and the ear piece  1204 . The cell phone  1200  contains the functional device  1  that functions as an acceleration sensor or the like for sensing acceleration or the like applied to the cell phone  1200  and assisting the operation of the cell phone  1200 . In the functional device  1 , breakage due to a vibration by the operation of the cell phone  1200  and an impact with drop may be suppressed, and the physical quantity may be continuously detected. Thus, the reliable cell phone  1200  may be obtained. 
       FIG. 10  is a perspective view showing an outline of a configuration of a digital still camera as the electronic apparatus including the functional device according to one embodiment of the invention. Note that, in the drawing, connection to an external device is simply shown. Here, in a typical camera, a silver halide photographic film is exposed to light by an optical image of a subject and, on the other hand, a digital still camera  1300  photoelectrically converts an optical image of a subject using an image sensing device such as a CCD (Charge Coupled Device) and generates imaging signals (image signals). 
     On a back surface of a case (body)  1302  in the digital still camera  1300 , a display part  1308  is provided and adapted to display based on the imaging signals by the CCD, and the display part  1308  functions as a finder that displays the subject as an electronic image. Further, on the front side (the rear side in the drawing) of the case  1302 , a light receiving unit  1304  including an optical lens (imaging system), the CCD, etc. is provided. 
     When a photographer checks the subject image displayed on the display part  1308  and presses down a shutter button  1306 , the imaging signals of the CCD at the time are transferred and stored into a memory  1310 . Further, in the digital still camera  1300 , a video signal output terminal  1312  and an input/output terminal for data communication  1314  are provided on the side surface of the case  1302 . Furthermore, as illustrated, a liquid crystal display  1430  is connected to the video signal output terminal  1312  and a personal computer  1440  is connected to the input/output terminal for data communication  1314 , respectively, as appropriate. In addition, by predetermined operation, the imaging signals stored in the memory  1310  are output to the liquid crystal display  1430  and the personal computer  1440 . The digital still camera  1300  contains the functional device  1  that functions as an acceleration sensor that senses acceleration due to drop for operating the function of protecting the digital still camera  1300  from drop. In the functional device  1 , breakage due to a vibration by the operation of the digital still camera  1300  and an impact with drop may be suppressed, and the physical quantity may be continuously detected. Thus, the reliable digital still camera  1300  may be obtained. 
     Note that the functional device  1  according to one embodiment of the invention may be applied not only to the laptop personal computer (mobile personal computer) in  FIG. 8 , the cell phone in  FIG. 9 , and the digital still camera in  FIG. 10  but also to an electronic apparatus including an inkjet ejection device (for example, an inkjet printer), a television, a video camera, a video tape recorder, a car navigation system, a pager, a personal digital assistance (with or without communication function), an electronic dictionary, a calculator, an electronic game machine, a word processor, a work station, a videophone, a security television monitor, electronic binoculars, a POS terminal, a medical device (for example, an electronic thermometer, a sphygmomanometer, a blood glucose meter, an electrocardiographic measurement system, an ultrasonic diagnostic system, or an electronic endoscope), a fish finder, various measurement instruments, meters and gauges (for example, meters for vehicles, airplanes, and ships), and a flight simulator, for example. 
     Moving Object 
       FIG. 11  is a perspective view schematically showing an automobile as an example of a moving object. In an automobile  1500 , the functional device  1  that functions as an acceleration sensor is mounted on various kinds of control units. For example, as shown in the drawing, in the automobile  1500  as the moving object, an electronic control unit (ECU)  1508  that contains the functional device  1  that senses the acceleration of the automobile  1500  and controls output of the engine is mounted on a vehicle body  1507 . The acceleration is sensed and the engine is controlled to appropriate output in response to the attitude of the vehicle body  1507 , and thereby, the automobile  1500  as an efficient moving object with suppressed consumption of fuel or the like may be obtained. 
     In addition, the functional device  1  may be widely applied to a vehicle body attitude control unit, an antilock brake system (ABS), an airbag, or a tire pressure monitoring system (TPMS). 
     In the functional device  1 , breakage due to a vibration and an impact from the automobile  1500  may be suppressed, and the physical quantity may be continuously detected. Thus, the reliable automobile  1500  may be obtained.