Patent Publication Number: US-2023136163-A1

Title: Physical Quantity Sensor and Inertial Measurement Device

Description:
The present application is based on, and claims priority from JP Application Serial Number 2021-177278, filed Oct. 29, 2021, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a physical quantity sensor and an inertial measurement device. 
     2. Related Art 
     There has been known a physical quantity sensor that detects a physical quantity such as acceleration. As such a physical quantity sensor, there is, for example, a sensor disclosed in JP-A-2021-32820 (Patent Literature 1). Patent Literature 1 discloses a physical quantity sensor in which a plurality of sensor elements that respectively include fixed electrodes and movable electrodes and detect physical quantities are disposed. 
     In the physical quantity sensor disclosed in Patent Literature 1, the plurality of sensor elements are disposed in parallel in a Y-axis direction. Accordingly, a dead space is easily formed and it is difficult to reduce the size of the physical quantity sensor. Since fixed sections of the sensor elements are disposed to be separated, the sensor elements are easily affected by a warp of a substrate. It is difficult to perform accurate detection. 
     SUMMARY 
     An aspect of the present disclosure relates to a physical quantity sensor including: a first fixed electrode section and a second fixed electrode section provided on a substrate; a first movable electrode section provided such that a movable electrode is opposed to a fixed electrode of the first fixed electrode section; a second movable electrode section provided such that a movable electrode is opposed to a fixed electrode of the second fixed electrode section; a first fixed section and a second fixed section fixed to the substrate; a first support beam, one end of which is coupled to the first fixed section; a first coupling section configured to couple another end of the first support beam and the first movable electrode section; a second support beam, one end of which is coupled to the second fixed section; and a second coupling section configured to couple another end of the second support beam and the second movable electrode section. When three directions orthogonal to one another are represented as a first direction, a second direction, and a third direction, in a plane view in the third direction orthogonal to the substrate, the first movable electrode section, the second fixed section, the first fixed section, and the second movable electrode section are disposed side by side in the first direction in order of the first movable electrode section, the second fixed section, the first fixed section, and the second movable electrode section. 
     Another aspect of the present disclosure relates to an inertial measurement device including: the physical quantity sensor described above; and a control section configured to perform control based on a detection signal output from the physical quantity sensor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a plan view showing a configuration example of a physical quantity sensor in an embodiment. 
         FIG.  2    is an explanatory diagram of the disposition of the physical quantity sensor. 
         FIG.  3    is an explanatory diagram of the operation of detecting sections. 
         FIG.  4    is an explanatory diagram of the operation of the detecting sections. 
         FIG.  5    is an explanatory diagram of the operation of the detecting sections. 
         FIG.  6    is a plan view showing another configuration example of the physical quantity sensor. 
         FIG.  7    is a plan view showing another configuration example of the physical quantity sensor. 
         FIG.  8    is a plan view showing another configuration example of the physical quantity sensor. 
         FIG.  9    is a plan view showing another configuration example of the physical quantity sensor. 
         FIG.  10    is an exploded perspective view showing a schematic configuration of an inertial measurement device including the physical quantity sensor. 
         FIG.  11    is a perspective view of a circuit board of the physical quantity sensor. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     An embodiment is explained below. The embodiment explained below does not unduly limit description content of claims. Not all of components explained in this embodiment are essential constituent elements. 
     1. Physical Quantity Sensor 
     A configuration example of a physical quantity sensor  1  in this embodiment is explained with reference to  FIG.  1    citing, as an example, an acceleration sensor that detects acceleration in the vertical direction.  FIG.  1    is a plan view in a plane view in a direction orthogonal to a substrate  2  of the physical quantity sensor  1 . The physical quantity sensor  1  is an MEMS (Micro Electro Mechanical System) device and is, for example, an inertial sensor. 
     In  FIG.  1    and  FIGS.  6  to  9    and the like referred to below, for convenience of explanation, dimensions of members, intervals among the members, and the like are schematically shown. Not all of components are shown. For example, illustration is omitted about electrode wires, electrode terminals, and the like. In the following explanation, an example is mainly explained in which a physical quantity detected by the physical quantity sensor  1  is acceleration. However, the physical quantity is not limited to the acceleration and may be other physical quantity such as speed, pressure, displacement, angular velocity, or gravity. The physical sensor  1  may be used as a pressure sensor, an MEMS switch, or the like. Directions orthogonal to one another in  FIG.  1    are represented as a first direction DR 1 , a second direction DR 2 , and a third direction DR 3 . The first direction DR 1 , the second direction DR 2 , and the third direction DR 3  are respectively, for example, an X-axis direction, a Y-axis direction, and a Z-axis direction but are not limited to this. For example, the third direction DR 3  corresponding to the Z-axis direction is, for example, a direction orthogonal to the substrate  2  of the physical quantity sensor  1  and is, for example, the vertical direction. The first direction DR 1  corresponding to the X-axis direction and the second direction DR 2  corresponding to the Y-axis direction are directions orthogonal to the third direction DR 3 . An XY plane, which is a surface in the first direction DR 1  and the second direction DR 2 , is along, for example, a horizontal plane. “Orthogonal” includes crossing at an angle slightly tilting from 90° besides crossing at 90°. 
     The substrate  2  is, for example, a silicon substrate made of semiconductor silicon or a glass substrate made of a glass material such as borosilicate glass. However, a constituent material of the substrate  2  is not particularly limited. A quartz substrate, an SOI (Silicon On Insulator) substrate, or the like may be used. 
     As shown in  FIG.  1   , the physical quantity sensor  1  in this embodiment includes a first fixed electrode section  10 , a first movable electrode section  20 , a first coupling section  30 , a first fixed section  40 , and first support beams  42 . A first element section  91  of the physical quantity sensor  1  is configured by the first fixed electrode section  10 , the first movable electrode section  20 , the first coupling section  30 , the first fixed section  40 , and the first support beams  42 . The first element section  91  detects, for example, acceleration in the third direction DR 3 , which is the Z-axis direction, in a detecting section Z 1 . 
     The physical quantity sensor  1  includes a second fixed electrode section  50 , a second movable electrode section  60 , a second coupling section  70 , a second fixed section  80 , and second support beams  82 . A second element section  92  of the physical quantity sensor  1  is configured by the second fixed electrode section  50 , the second movable electrode section  60 , the second coupling section  70 , the second fixed section  80 , and the second support beams  82 . The second element section  92  detects, for example, acceleration in the third direction DR 3 , which is the Z-axis direction, in a detecting section Z 2 . 
     The first fixed electrode section  10  and the second fixed electrode section  50  are provided on the substrate  2 . Specifically, the first fixed electrode section  10  is fixed to the substrate  2  by fixed sections  3  and  4 . The second fixed electrode section  50  is fixed to the substrate  2  by fixed sections  5  and  6 . The first fixed electrode section  10  and the second fixed electrode section  50  include pluralities of fixed electrodes. The pluralities of fixed electrodes extend, for example, in the first direction DR 1 , which is the X-axis direction. For example, the first fixed electrode section  10  is a first fixed electrode group and the second fixed electrode section  50  is a second fixed electrode group. 
     The first movable electrode section  20  is provided such that movable electrodes are opposed to the fixed electrodes of the first fixed electrode section  10 . The second movable electrode section  60  is provided such that movable electrodes are opposed to the fixed electrodes of the second fixed electrode section  50 . The first movable electrode section  20  and the second movable electrode section  60  include pluralities of movable electrodes. The plurality of movable electrodes extend, for example, in the first direction DR 1 , which is the X-axis direction. For example, the first movable electrode section  20  is a first movable electrode group and the second movable electrode section  60  is a second movable electrode group. Specifically, first movable electrodes  21  and second movable electrodes  22  of the first movable electrode section  20  are opposed to first fixed electrodes  11  and second fixed electrodes  12  of the first fixed electrode section  10  in the second direction DR 2 , which is the Y-axis direction. Third movable electrodes  61  and fourth movable electrodes  62  of the second movable electrode section  60  are opposed to third fixed electrodes  51  and fourth fixed electrodes  52  of the second fixed electrode section  50  in the second direction DR 2 , which is the Y-axis direction. 
     For example, in  FIG.  1   , the first movable electrode section  20  and the second movable electrode section  60  are interdigital movable electrode groups in which pluralities of movable electrodes are disposed in a interdigital shape in a plane view in the third direction DR 3 . The first fixed electrode section  10  and the second fixed electrode section  50  are interdigital fixed electrode groups in which pluralities of fixed electrodes are disposed in a interdigital shape in the plane view in the third direction DR 3 . In the detecting section Z 1  of the first element section  91 , the movable electrodes of the interdigital movable electrode group of the first movable electrode section  20  and the fixed electrodes of the interdigital fixed electrode group of the first fixed electrode section  10  are disposed to be alternately opposed to each other. In the detecting section Z 2  of the second element section  92 , the movable electrodes of the interdigital movable electrode group of the second movable electrode section  60  and the fixed electrodes of the interdigital fixed electrode group of the second fixed electrode section  50  are disposed to be alternately opposed to each other. 
     The first fixed section  40  and the second fixed section  80  are fixed to the substrate  2 . One ends of the first support beams  42  are coupled to the first fixed section  40 . One ends of the second support beams  82  are coupled to the second fixed section  80 . For example, the first support beams  42  are first torsion springs and the second support beams  82  are second torsion springs. In  FIG.  1   , as the first support beams  42 , two support beams extending in the second direction DR 2 , that is, the first support beam  42  extending from the first fixed section  40  to the second direction DR 2  side and the first support beam  42  extending from the first fixed section  40  to the opposite direction side of the second direction DR 2  are provided. As the second support beams  82 , two support beams extending in the second direction DR 2 , that is, the second support beam  82  extending from the second fixed section  80  to the second direction DR 2  side and the second support beam  82  extending from the second fixed section  80  to the opposite direction side of the second direction DR 2  are provided. 
     The first fixed section  40  is used as an anchor of a first movable body configured by the first movable electrode section  20  and the first coupling section  30 . The first movable body including the first movable electrode section  20  seesaws around a rotation axis extending in the second direction DR 2  with the first fixed section  40  as a fulcrum. For example, the first movable body swings, with the first support beam  42  extending in the second direction DR 2  as a rotation axis, around the rotation axis while torsionally deforming the first support beam  42 . Consequently, the first element section  91  having a one-side seesaw structure is realized. 
     The second fixed section  80  is used as an anchor of a second movable body configured by the second movable electrode section  60  and the second coupling section  70 . The second movable body including the second movable electrode section  60  seesaws around a rotation axis extending in the second direction DR 2  with the second fixed section  80  as a fulcrum. For example, the second movable body swings, with the second support beam  82  extending in the second direction DR 2  as a rotation axis, around the rotation axis while torsionally deforming the second support beam  82 . Consequently, the second element section  92  having a one-side seesaw structure is realized. 
     That is, whereas the first movable body including the first movable electrode section  20  seesaws with the first fixed section  40  located further in the first direction DR 1  than the first movable electrode section  20  as the fulcrum, the second movable body including the second movable electrode section  60  seesaws with the second fixed section  80  located further on the opposite side in the first direction DR 1  than the second movable electrode section  60  as the fulcrum. In the plane view in the third direction DR 3  orthogonal to the substrate  2 , the first movable electrode section  20 , the first coupling section  30 , and the first fixed section  40  are disposed in the first direction DR 1  in the order of the first movable electrode section  20 , the first coupling section  30 , and the first fixed section  40 . The second movable electrode section  60 , the second coupling section  70 , and the second fixed section  80  are disposed in the opposite direction of the first direction DR 1  in the order of the second movable electrode section  60 , the second coupling section  70 , and the second fixed section  80 . Therefore, the first element section  91  is disposed point-symmetrically to the second element section  92  with respect to a virtual point between the first fixed section  40  and the second fixed section  80 . Specifically, the first fixed section  40  is disposed point-symmetrically to the second fixed section  80  and the first movable electrode section  20  is disposed point-symmetrically to the second movable electrode section  60  with respect to the virtual point. 
     The first coupling section  30  couples the other ends of the first support beams  42  and the first movable electrode section  20 . Specifically, the other ends of the two first support beams  42 , one ends of which are coupled to the first fixed section  40 , are coupled to the first coupling section  30 . The second coupling section  70  couples the other ends of the second support beams  82  and the second movable electrode section  60 . Specifically, the other ends of the two second support beams  82 , one ends of which are coupled to the second fixed section  80 , are coupled to the second coupling section  70 . 
     The first coupling section  30  includes a first portion  31  disposed in the second direction DR 2  side by side with the first support beams  42  and a second portion  32  coupled to the first portion  31  and the first movable electrode section  20  and disposed in the first direction DR 1 . The first coupling section  30  includes a third portion  33  coupled to the second portion  32  and disposed in the second direction DR 2 . The first portion  31  is coupled to the other ends of the two first support beams  42 , to one ends of which the first fixed section  40  is coupled. One end of the second portion  32  is coupled to the first portion  31 . The other end of the second portion  32  is coupled to the third portion  33  and the first movable electrode section  20 . The first portion  31 , the second portion  32 , and the third portion  33  of the first coupling section  30  function as mass sections of the first movable body. In particular, the third portion  33  present at a far distance from the first support beams  42  serving as a rotation axis of the first movable body is a mass section effective for sensitivity improvement. 
     The second coupling section  70  includes a fourth portion  71  disposed in the second direction DR 2  side by side with the second support beams  82  and a fifth portion  72  coupled to the fourth portion  71  and the second movable electrode section  60  and disposed in the first direction DR 1 . The second coupling section  70  includes a sixth portion  73  coupled to the fifth portion  72  and disposed in the second direction DR 2 . The fourth portion  71  is coupled to the other ends of the two second support beams  82 , to one ends of which the second fixed section  80  is coupled. One end of the fifth portion  72  is coupled to the fourth portion  71 . The other end of the fifth portion  72  is coupled to the sixth portion  73  and the second movable electrode section  60 . The fourth portion  71 , the fifth portion  72 , and the sixth portion  73  of the second coupling section  70  function as mass sections of the second movable body. In particular, the sixth portion  73  present at a far distance from the second support bean  82  serving as a rotation axis of the second movable body is a mass section effective for sensitivity improvement. 
     As explained above, the physical quantity sensor  1  in this embodiment includes the first fixed electrode section  10  and the second fixed electrode section  50  provided on the substrate  2 , the first movable electrode section  20  provided such that the movable electrodes are opposed to the fixed electrodes of the first fixed electrode section  10 , and the second movable electrode section  60  provided such that the movable electrodes are opposed to the fixed electrodes of the second fixed electrode section  50 . The physical quantity sensor  1  includes the first fixed section  40  and the second fixed section  80  fixed to the substrate  2 , the first support beams  42 , one ends of which are coupled to the first fixed section  40 , the first coupling section  30  that couples the other ends of the first support beams  42  and the first movable electrode section  20 , the second support beams  82 , one ends of which are coupled to the second fixed section  80 , and the second coupling section  70  that couples the other ends of the second beams  82  and the second movable electrode section  60 . As shown in  FIGS.  1  and  2   , in the plane view in the third direction DR 3  orthogonal to the substrate  2 , the first movable electrode section  20 , the second fixed section  80 , the first fixed section  40 , and the second movable electrode section  60  are disposed in the first direction DR 1  in the order of the first movable electrode section  20 , the second fixed section  80 , the first fixed section  40 , and the second movable electrode section  60 . 
     With such a physical quantity sensor  1 , the second fixed section  80  of the second element section  92  can be disposed using a space between the first fixed section  40  of the first element section  91  and the first movable electrode section  20 . The first fixed section  40  of the first element section  91  can be disposed using a space between the second fixed section  80  of the second element section  92  and the second movable electrode section  60 . Therefore, the first movable electrode section  20 , the second fixed section  80 , the first fixed section  40 , and the second movable electrode section  60  can be compactly disposed side by side in the first direction DR 1 . A reduction in the size of the physical quantity sensor  1  can be realized. The first fixed section  40  and the second fixed section  80  can be disposed close to each other. Deterioration in accuracy due to the influence of a warp of the substrate  2  or the like of the physical quantity sensor  1  can be suppressed. Improvement of accuracy of the physical quantity sensor  1  can be realized. Therefore, both of the reduction in the size and the improvement of accuracy of the physical quantity sensor  1  can be realized. 
     With the physical quantity sensor  1  in this embodiment, the first movable electrode section  20  functioning as the mass section can be disposed to be separated from the first fixed section  40  and the first support beams  42  by the width of a space in which the second fixed section  80  and the second support beams  82  are disposed. Therefore, displacement of the first movable electrode section  20  at the time when acceleration or the like is applied can be increased. Improvement of sensitivity of detection of acceleration or the like in the first element section  91  can be realized. The second movable electrode section  60  functioning as the mass section can be disposed to be separated from the second fixed section  80  and the second support beams  82  by the width of a space in which the first fixed section  40  and the first support beams  42  are disposed. Therefore, displacement of the second movable electrode section  60  at the time when acceleration or the like is applied can be increased. Improvement of sensitivity of detection of acceleration or the like in the second element section  92  can be realized. Therefore, both of the reduction in the size and the improvement of accuracy of the physical quantity sensor  1  can be realized. 
     More specifically, in  FIGS.  1  and  2   , in the plane view in the third direction DR 3 , the first movable electrode section  20 , the second fixed section  80  and the second support beams  82 , the first fixed section  40  and the first support beams  42 , and the second movable electrode section  60  are disposed side by side in the first direction DR 1  in this order. Consequently, the second fixed section  80  and the second support beams  82  can be disposed using a space between the first fixed section  40  and the first support beams  42  and the first movable electrode section  20 . The first fixed section  40  and the first support beams  42  can be disposed using a space between the second fixed section  80  and the second support beams  82  and the second movable electrode section  60 . Therefore, the first movable electrode section  20 , the second fixed section  80  and the second support beams  82 , the first fixed section  40  and the first support beams  42 , and the second movable electrode section  60  can be compactly disposed side by side in the first direction DR 1 . A reduction in the size of the physical quantity sensor  1  can be realized. 
     For example, in the physical quantity sensor disclosed in Patent Literature 1 explained above, the first element section and the second element section, each of which is formed in the one-side seesaw structure, are disposed in parallel in the Y-axis direction and the thicknesses in the Z-axis direction of the movable electrode and the fixed electrode are respectively set such that differential detection can be performed. In the physical quantity sensor, in the element sections having the one-side seesaw structure, rotation torque easily occurs because mass concentrates on one side. Improvement of sensitivity is realized by adopting a two-element configuration. However, in the configuration in which the first element section and the second element section are disposed in parallel in the Y-axis direction as in Patent Literature 1, a dead space is easily formed and it is difficult to reduce size. When acceleration is applied in other axis direction different from the Z-axis direction such as the X-axis direction, an opposing area between the movable electrode and the fixed electrode increases in one of the first element section and the second element section and the opposing area decreases in the other of the first element section and the second element section. Therefore, the opposing areas cannot be offset. Other axis sensitivity is deteriorated. Since the distance between the first fixed section of the first element section and the second fixed section of the second element section is large, the first element section and the second element section are easily affected by a warp of the substrate or the like. It is difficult to perform accurate detection. 
     As a first comparative example of this embodiment, a physical quantity sensor not having the one-side seesaw structure but having a seesaw structure in which detecting sections, movable electrodes and fixed electrodes of which are opposed, are provided on both sides of a rotation axis is conceivable. However, in this first comparative example, displacement less easily occurs even if the detection sections are simply doubled compared with the one-side seesaw structure. Therefore, sensitivity is not simply doubled. Specifically, in the seesaw structure of the first comparative example, rotation torque represented by mass×distance is in an offset relation in symmetry regions with respect to the rotation axis in the movable body and only an asymmetry portion can contribute to the rotation torque. Therefore, as a method of improving sensitivity, there is a method of increasing the asymmetry portion in size. However, in this method, improvement of sensitivity is difficult when compared with sensitivity of the one-side seesaw structure in the same area. As another method, there is a method of reducing spring rigidity of the torsion spring to gain displacement. However, shock resistance is deteriorated when compared with shock resistance of the one-side seesaw structure in the same sensitivity. 
     As a second comparative example of this embodiment, a physical quantity sensor in which the first fixed section, the second movable electrode section, the first movable electrode section, and the second fixed section are disposed side by side in the second direction in this order is conceivable. However, in this second comparative example, since the distance between the first fixed section and the second fixed section is large, if a warp occurs in the substrate because of stress, influence due to the warp is different in the first fixed section and the second fixed section. The influence on the individual element sections cannot be offset. Therefore, the element sections are easily affected by thermal stress and external stress. 
     In this regard, in this embodiment, for example, in a Z-axis acceleration sensor having, for example, an area change type structure by out-of-plane mobility of a fixed electrode and a movable electrode having different thicknesses, the one-side seesaw structure is realized, the one-side seesaw structure being a structure in which a support beam, which is a torsion spring, and a portion of a movable body up to a movable electrode section are opened is realized. A two-element configuration such as the first element section  91  and the second element section  92  is adopted, the two-element configuration being a configuration in which a fixed section and a support beam of the other element section are disposed in an opening section of one element section. In the one-side seesaw structures, movable electrodes are extended on both sides in an in-plane direction orthogonal to a rotation axis. 
     Specifically, the physical quantity sensor  1 , which is the Z-axis acceleration sensor of the area change type shown in  FIG.  1   , includes the first fixed electrode section  10 , the second fixed electrode section  50 , the first fixed section  40 , and the second fixed section  80  fixed to the substrate  2 , which is a support substrate. The physical quantity sensor  1  includes the first movable electrode section  20  and the first coupling section  30 , which are the first movable body, the second movable electrode section  60  and the second coupling section  70 , which are the second movable body, the first support beams  42  coupled to the first coupling section  30  of the first movable body and the first fixed section  40 , and the second support beams  82  coupled to the second coupling section  70  of the second movable body and the second fixed section  80 . The first movable electrode section  20  includes the first movable electrodes  21  and the second movable electrodes  22  extending to both sides in the first direction DR 1  from a first base movable electrode  23  of the first movable body. The second movable electrode section  60  includes the third movable electrodes  61  and the fourth movable electrodes  62  extending to both sides in the first direction DR 1  from a second base movable electrode  63  of the second movable body. 
     In the physical quantity sensor  1  shown in  FIG.  1   , when acceleration in the Z-axis direction is applied, the first movable body of the first element section  91  rotates with the first support beams  42 , which are the torsion springs, as a rotation axis and the second movable body of the second element section  92  rotates with the second support beams  82 , which are the torsion springs, as a rotation axis. In one detecting section of the detecting section Z 1  of the first element section  91  and the detecting section Z 2  of the second element section  92 , the opposing area between the movable electrode and the fixed electrode decreases. In the other detecting section, the opposing area is constant or increases. Referring to  FIG.  5    as an example, when acceleration in the third direction DR 3 , which is a Z-axis direction plus side, is applied, the opposing area of the detecting section Z 2  of the second element section  92  decreases and the opposing area of the detecting section Z 1  of the first element section  91  does not change and is constant. On the other hand, when acceleration in a fourth direction DR 4 , which is a Z-axis direction minus side and the opposite direction of the third direction DR 3 , is applied, the opposing area of the detecting section Z 1  of the first element section  91  decreases and the opposing area of the detecting section Z 2  of the second element section  92  does not change and is constant. By detecting a change in capacitance due to a change in the opposing area between the movable electrode and the fixed electrode, the magnitude and the direction of applied acceleration can be detected. 
     As a characteristic of the structure of the physical quantity sensor  1  shown in  FIG.  1   , the one-side seesaw structure in which a portion of the movable body from the support beam to the movable electrode section is opened is adopted. For example, the first element section  91  is formed in the one-side seesaw structure in which a portion of the first movable body from the first support beams  42  to the first movable electrode section  20  is opened. Specifically, a region surrounded by the first portion  31 , the second portion  32 , and the third portion  33  of the first coupling section  30  is an opening section. The second fixed section  80  and the second support beams  82  of the second element section  92  are disposed in the opening section. The second element section  92  is formed in the one-side seesaw structure in which a portion of the second movable body from the second support beams  82  to the second movable electrode section  60  is opened. Specifically, a region surrounded by the fourth portion  71 , the fifth portion  72 , and the sixth portion  73  of the second coupling section  70  is an opening section. The first fixed section  40  and the first support beams  42  of the first element section  91  are disposed in the opening section. 
     In the one-side seesaw structure shown in  FIG.  1   , compared with the normal seesaw structure, the mass of the entire first and second movable bodies contribute as rotation torque represented by mass×distance. Therefore, displacement can be gained, which is advantageous in improvement of sensitivity. 
     In  FIG.  1   , portions of the movable bodies are opened. However, since contribution of mass at a farther distance to the rotation torque is larger, even if a part of mass close to the rotation axis is absent, displacement does not greatly decrease. Therefore, a decrease in sensitivity is little. For example, in the first element section  91 , a portion surrounded by the first portion  31 , the second portion  32 , and the third portion  33  of the first coupling section  30  is an opening section. Mass is absent in the opening section. However, since the opening section is located at a short distance from the first support beams  42 , which are the rotation axis, a decrease in sensitivity by providing the opening section is little. For example, in the first element section  91 , since the first movable electrode section  20 , the third portion  33 , and the like function as mass sections far from the first support beams  42 , which are the rotation axis, improvement of sensitivity can be realized. In the second element  92 , a portion surrounded by the fourth portion  71 , the fifth portion  72 , and the sixth portion  73  of the second coupling section  70  is an opening section. Mass is absent in the opening section. However, since the opening section is located at a short distance from the second support beams  82 , which are the rotation axis, a decrease in sensitivity by providing the opening section is little. For example, in the second element section  92 , since the second movable electrode section  60  and the sixth portion  73  function as mass sections far from the second support beams  82 , which are the rotation axis, improvement of sensitivity can be realized. 
     In  FIG.  1   , the fixed section and the support beam of the other element section are disposed in the opening section of the movable body of one element section using the first element section  91  and the second element section  92  of such a structure. For example, the second fixed section  80  and the second support beams  82  of the second element section  92  are disposed in the region surrounded by the first portion  31 , the second portion  32 , and the third portion  33 , which is the opening section of the first movable body of the first element section  91 . The first fixed section  40  and the first support beams  42  of the first element section  91  are disposed in the region surrounded by the fourth portion  71 , the fifth portion  72 , and the sixth portion  73 , which is the opening section of the second movable body of the second element section  92 . By adopting such a structure, the space formed as the dead space in Patent Literature 1 explained above can be effectively used. Therefore, a reduction in the size of the physical quantity sensor  1  can be realized. 
     In  FIG.  1   , the first fixed section  40  and the second fixed section  80 , which are the anchors, are disposed close to each other. Therefore, even if a warp of the substrate  2  is caused by stress, the warp affects the fixed sections in the same manner. Therefore, influence in the individual element sections can be offset. It is possible to realize a structure that is less easily affected by thermal stress and external stress. 
     In  FIG.  1   , the movable electrode section is formed in a structure in which the two movable electrodes extend to both sides from the base movable electrode. Therefore, since the opposing area between the movable electrode and the fixed electrode does not change with respect to application of acceleration in the other axis direction of the length direction of the movable electrode, deterioration in the other axis sensitivity can be suppressed. For example, in the first movable electrode section  20 , the first movable electrodes  21  and the second movable electrodes  22  extend to both sides in the first direction DR 1  from the first base movable electrode  23  extending in the second direction DR 2 . Therefore, since an opposing area between the first movable electrodes  21 , the second movable electrodes  22  and the first fixed electrodes  11 , the second fixed electrodes  12  does not change with respect to application of acceleration, for example, in the direction of the X axis, which is the other axis of the Z axis, deterioration in the other axis sensitivity can be suppressed. In the second movable electrode section  60 , the third movable electrodes  61  and the fourth movable electrodes  62  extend to both sides in the first direction DR 1  from the second base movable electrode  63  extending in the second direction DR 2 . Therefore, since an opposing area between the third movable electrodes  61 , the fourth movable electrodes  62  and the third fixed electrodes  51 , the fourth fixed electrodes  52  does not change with respect to application of acceleration, for example, in the direction of the X axis, which is the other axis, deterioration in the other axis sensitivity can be suppressed. 
       FIGS.  3  to  5    are explanatory diagrams of the operations of the detecting sections Z 1  and Z 2  in which the movable electrodes and the fixed electrodes are opposed. In the detecting sections Z 1  and Z 2 , the thicknesses in the third direction DR 3  of the movable electrodes and the fixed electrodes are different. Specifically, as shown in  FIG.  3   , in the detecting section Z 1 , the thickness in the third direction DR 3  of the movable electrodes  24  of the first movable electrode section  20  is larger than the thickness in the third direction DR 3  of the fixed electrodes  14  of the first fixed electrode section  10 . On the other hand, as shown in  FIG.  4   , in the detecting section Z 2 , the thickness in the third direction DR 3  of the movable electrodes  64  of the second movable electrode section  60  is smaller than the thickness in the third direction DR 3  of the fixed electrodes  54  of the second fixed electrode section  50 . The movable electrodes  24  shown in  FIG.  3    correspond to the first movable electrodes  21  and the second movable electrodes  22  shown in  FIG.  1   . The fixed electrodes  14  shown in  FIG.  3    correspond to the first fixed electrodes  11  and the second fixed electrodes  12  shown in  FIG.  1   . The movable electrodes  64  shown in  FIG.  4    correspond to the third movable electrodes  61  and the fourth movable electrodes  62  shown in  FIG.  1   . The fixed electrodes  54  shown in  FIG.  4    correspond to the third fixed electrodes  51  and the fourth fixed electrodes  52  shown in  FIG.  1   . 
     As shown in  FIG.  5   , in an initial state, in a side view in the second direction DR 2 , the positions of the end portions on the fourth direction DR 4  side of the movable electrodes  24  and the fixed electrodes  14  coincide and the end portions are flush. The positions of the end portions on the fourth direction DR 4  side of the movable electrodes  64  and the fixed electrodes  54  also coincide and the end portions are flush. The initial state is a state at the time when acceleration is not applied and is a stationary state. The fourth direction DR 4  is the opposite direction of the third direction DR 3  and is, for example, a direction on a Z-axis direction minus side. 
     When acceleration in the third direction DR 3  is applied in the initial state, as shown in  FIG.  5   , the movable electrodes  24  and  64  are displaced to the fourth direction DR 4  side, which is the opposite direction of the third direction DR 3 . Consequently, in the detecting section Z 2 , an opposing area between the movable electrodes  64  and the fixed electrodes  54  decreases. In the detecting section Z 1 , an opposing area between the movable electrodes  24  and the fixed electrodes  14  is maintained constant. Therefore, the acceleration in the third direction DR 3  can be detected by detecting a change in capacitance due to the decrease in the opposing area in the detecting section Z 2 . On the other hand, when acceleration in the fourth direction DR 4  is applied in the initial state, as shown in  FIG.  5   , the movable electrodes  24  and  64  are displaced to the third direction DR 3  side. Consequently, in the detecting section Z 1 , the opposing area between the movable electrodes  24  and the fixed electrodes  14  decreases. In the detecting section Z 2 , the opposing area between the movable electrodes  64  and the fixed electrodes  54  is maintained constant. Therefore, the acceleration in the fourth direction DR 4  can be detected by detecting a change in capacitance due to the decrease in the opposing area in the detecting section Z 1 . Specifically, the movable electrodes  24  are electrically coupled to a first input terminal for differential amplification, a differential detection circuit to which the movable electrodes  64  are electrically coupled is provided in a second input terminal for differential amplification, and the acceleration in the third direction DR 3  and the acceleration in the fourth direction DR 4  are detected by the differential detection circuit. One input terminal of the first input terminal and the second input terminal of the differential detection circuit is an inverted input terminal and the other input terminal is a noninverting input terminal. 
     In  FIGS.  3  to  5   , in the initial state, the end portions on the fourth direction DR 4  side of the movable electrodes  24  and  64  and the fixed electrodes  14  and  54  coincide and are flush. However, this embodiment is not limited to this. For example, in the initial state, in the detecting section Z 1 , the movable electrodes  24  may be offset and displaced to the third direction DR 3  side to prevent one ends on the third direction DR 3  side and the other ends on the fourth direction DR 4  side of the movable electrodes  24  and the fixed electrodes  14  from coinciding. In the detecting section Z 2 , the movable electrodes  64  may be offset and displaced to the fourth direction DR 4  side to prevent one ends on the third direction DR 3  side and the other ends on the fourth direction DR 4  side of the movable electrodes  64  and the fixed electrodes  54  from coinciding. Consequently, for example, when acceleration is applied in the third direction DR 3 , the opposing area increases and the capacitance increases in the detecting section Z 1  and the opposing area decreases and the capacitance decreases in the detecting section Z 2 . On the other hand, when acceleration is applied in the fourth direction DR 4 , the opposing area decreases and the capacitance decreases in the detecting section Z 1  and the opposing area increases and the capacitance increases in the detecting section Z 2 . Consequently, since a ratio of a change in the capacitance to a change in the acceleration increases, it is possible to realize the physical quantity sensor  1  having higher sensitivity. 
     As explained above, in this embodiment, the movable electrodes  24  of the first movable electrode section  20  and the fixed electrodes  14  of the first fixed electrode section  10  are opposed in the second direction DR 2 . The movable electrodes  64  of the second movable electrode section  60  and the fixed electrodes  54  of the second fixed electrode section  50  are opposed in the second direction DR 2 . For example, movable electrodes of a movable electrode group of the first movable electrode section  20  and fixed electrodes of a fixed electrode group of the first fixed electrode section  10  are opposed in the second direction DR 2 . The movable electrodes of the movable electrode group of the second movable electrode section  60  and the fixed electrodes of the fixed electrode group of the second fixed electrode section  50  are opposed in the second direction DR 2 . 
     Consequently, for example, a change in a physical quantity such as acceleration in the third direction DR 3  orthogonal to the second direction DR 2  can be measured by detecting a change in the capacitance due to a change in an opposing area between the first movable electrode section  20  and the first fixed electrode section  10  and a change in capacitance due to a change in an opposing area between the second movable electrode section  60  and the second fixed electrode section  50 . 
     In this embodiment, as shown in  FIG.  1   , the first movable electrode section  20  includes the first base movable electrode  23 , the first movable electrodes  21  extending in the first direction DR 1  from the first base movable electrode  23 , and the second movable electrodes  22  extending in the opposite direction of the first direction DR 1  from the first base movable electrode  23 . The first fixed electrode section  10  includes the first fixed electrodes  11  opposed to the first movable electrodes  21  and the second fixed electrodes  12  opposed to the second movable electrodes  22 . The first base movable electrode  23  is, for example, a portion extending, for example, in the second direction DR 2  from one end of the first coupling section  30  and is a portion functioning as a base of the movable electrode group of the first movable electrode section  20 . 
     Consequently, when a physical quantity such as acceleration, for example, in the first direction DR 1 , which is the other axis direction, changes, for example, one opposing area of an opposing area between the first movable electrodes  21  and the first fixed electrodes  11  and an opposing area between the second movable electrodes  22  and the second fixed electrodes  12  decreases and the other opposing area increases. Therefore, changes in the opposing areas can be offset when the physical quantity such as acceleration in the other axis direction changes. Deterioration in the other axis sensitivity can be suppressed. 
     In this embodiment, as shown in  FIG.  1   , the second movable electrode section  60  includes the second base movable electrode  63 , the third movable electrodes  61  extending in the first direction DR 1  from the second base movable electrode  63 , and the fourth movable electrodes  62  extending in the opposite direction of the first direction DR 1  from the second base movable electrode  63 . The second fixed electrode section  50  includes the third fixed electrodes  51  opposed to the third movable electrodes  61  and the fourth fixed electrodes  52  opposed to the fourth movable electrodes  62 . The second base movable electrode  63  is, for example, a portion extending, for example, in the second direction DR 2  from one end of the second coupling section  70  and is a portion functioning as a base of the movable electrode group of the second movable electrode section  60 . 
     Consequently, when the physical quantity such as acceleration, for example, in the first direction DR 1 , which is the other axis direction, changes, for example, one opposing area of an opposing area between the third movable electrodes  61  and the third fixed electrodes  51  and an opposing area between the fourth movable electrodes  62  and the fourth fixed electrodes  52  decreases and the other opposing area increases. Therefore, changes in the opposing areas can be offset when the physical quantity such as acceleration in the other axis direction changes. Deterioration in the other axis sensitivity can be suppressed. 
     In this embodiment, as shown in  FIG.  5   , when the first movable electrode section  20  and the second movable electrode section  60  are displaced in the third direction DR 3 , capacitance between the first movable electrode section  20  and the first fixed electrode section  10  decreases. Specifically, when acceleration or the like is applied to the fourth direction DR 4  side and the first movable electrode section  20  and the second movable electrode section  60  are displaced in the third direction DR 3 , the opposing area between the movable electrodes  24  of the first movable electrode section  20  and the fixed electrodes  14  of the first fixed electrode section  10  decreases and the capacitance between the first movable electrode section  20  and the first fixed electrode section  10  decreases. At this time, capacitance between the second movable electrode section  60  and the second fixed electrode section  50  may be maintained constant as shown in  FIG.  5    or may increase. 
     As shown in  FIG.  5   , when the first movable electrode section  20  and the second movable electrode section  60  are displaced in the fourth direction DR 4 , which is the opposite direction of the third direction DR 3 , the capacitance between the second movable electrode section  60  and the second fixed electrode section  50  decreases. Specifically, when acceleration or the like is applied to the third direction DR 3  side and the first movable electrode section  20  and the second movable electrode section  60  are displaced in the fourth direction DR 4 , the opposing area between the movable electrodes  64  of the second movable electrode section  60  and the fixed electrodes  54  of the second fixed electrode section  50  decreases and the capacitance between the second movable electrode section  60  and the second fixed electrode section  50  decreases. At this time, the capacitance between the first movable electrode section  20  and the first fixed electrode section  10  may be maintained constant as shown in  FIG.  5    or may increase. 
     Consequently, by detecting, for example, a decrease in the capacitance between the first movable electrode section  20  and the fixed electrode section  10 , it is possible to detect that the first movable electrode section  20  and the second movable electrode section  60  are displaced in the third direction DR 3 . By detecting, for example, a decrease in the capacitance between the second movable electrode section  60  and the second fixed electrode section  50 , it is possible to detect that the first movable electrode section  20  and the second movable electrode section  60  are displaced in the fourth direction DR 4 . Therefore, it is possible to detect, at high sensitivity or the like, displacement in the third direction DR 3  and the fourth direction DR 4  of the first movable electrode section  20  and the second movable electrode section  60 . 
     2. Other Configuration Examples 
     Subsequently, various configuration examples of this embodiment are explained. Another configuration example of the physical quantity sensor  1  is shown in  FIG.  6   . In  FIG.  1   , the movable electrodes extend to both sides from the base movable electrode. However, in  FIG.  6   , the fixed electrodes extend to both sides from the base fixed electrode. 
     Specifically, in  FIG.  6   , the first fixed electrode section  10  includes a first base fixed electrode  13 , the first fixed electrodes  11  extending in the first direction DR 1  from the first base fixed electrode  13 , and the second fixed electrodes  12  extending in the opposite direction of the first direction DR 1  from the first base fixed electrode  13 . The first movable electrode section  20  includes the first movable electrodes  21  opposed to the first fixed electrodes  11  and the second movable electrodes  22  opposed to the second fixed electrodes  12 . The first base fixed electrode  13  is, for example, a portion extending, for example, in the second direction DR 2  from the fixed section  3  of the first fixed electrode section  10  and is a portion functioning as a base of the fixed electrode group of the first fixed electrode section  10 . For example, in  FIG.  1   , the first fixed electrode section  10  is supported at two points by the two fixed sections  3  and  4 . However, in  FIG.  6   , the first fixed electrode section  10  is supported at one point by one fixed section  3 . 
     Consequently, when a physical quantity such as acceleration, for example, in the first direction DR 1 , which is the other axis direction, changes, for example, one opposing area of the opposing area between the first movable electrodes  21  and the first fixed electrodes  11  and the opposed area between the second movable electrodes  22  and the second fixed electrodes  12  decreases and the other opposing area increases. Therefore, changes in the opposing areas can be offset when the physical quantity such as acceleration in the other axis direction changes. Deterioration in the other axis sensitivity can be suppressed. 
     In  FIG.  6   , the second fixed electrode section  50  includes a second base fixed electrode  53 , the third fixed electrodes  51  extending in the first direction DR 1  from the second base fixed electrode  53 , and the fourth fixed electrodes  52  extending in the opposite direction of the first direction DR 1  from the second base fixed electrode  53 . The second movable electrode section  60  includes the third movable electrodes  61  opposed to the third fixed electrodes  51  and the fourth movable electrodes  62  opposed to the fourth fixed electrodes  52 . The second base fixed electrode  53  is, for example, a portion extending, for example, in the second direction DR 2  from the fixed section  5  of the second fixed electrode section  50  and is a portion functioning as a base of the fixed electrode group of the second fixed electrode section  50 . For example, in  FIG.  1   , the second fixed electrode section  50  is supported at the two points by the two fixed sections  5  and  6 . However, in  FIG.  6   , the second fixed electrode section  50  is supported at one point by one fixed section  5 . 
     Consequently, when a physical quantity such as acceleration, for example, in the first direction DR 1 , which is the other axis direction, changes, for example, one opposing area of the opposing area between the first movable electrodes  21  and the first fixed electrodes  11  and the opposing area between the second movable electrodes  22  and the second fixed electrodes  12  decreases and the other opposing area increases. Therefore, changes in the opposing areas can be offset when the physical quantity such as acceleration in the other axis direction changes. Deterioration in the other axis sensitivity can be suppressed. 
     In  FIG.  6   , the first movable electrode section  20  is disposed on both sides of the first fixed electrode section  10  and the second movable electrode section  60  is disposed on both sides of the second fixed electrode section  50 . Therefore, compared with  FIG.  1   , it is possible to gain the mass of the first movable body including the first movable electrode section  20  and the mass of the second movable body including the second movable electrode section  60 . It is possible to realize improvement of sensitivity. In particular, a portion on the opposite direction side of the first direction DR 1  of the first fixed electrode section  10  in the first movable electrode section  20  and a portion on the first direction DR 1  side of the second fixed electrode section  50  in the second movable electrode section  60  function as mass sections far from the rotation axis. Therefore, it is possible to contribute to improvement of the sensitivity of the physical quantity sensor  1 . 
     Another configuration example of the physical quantity sensor  1  is shown in  FIG.  7   . In  FIG.  1   , one detecting section Z 1  explained with reference to  FIG.  3    is provided in a disposition region of the first movable electrode section  20  and the first fixed electrode section  10  of the first element section  91  and one detecting section Z 2  explained with reference to  FIG.  4    is provided in a disposition region of the second movable electrode section  60  and the second fixed electrode section  50  of the second element section  92 . In contrast, in  FIG.  7   , two detecting sections, that is, the detecting section Z 1  and the detecting section Z 2 , are provided in the disposition region of the first movable electrode section  20  and the first fixed electrode section  10  and two detecting sections, that is, the detecting section Z 1  and the detecting section Z 2 , are provided in the disposition region of the second movable electrode section  60  and the second fixed electrode section  50 . 
     As explained with reference to  FIG.  5   , the detecting section Z 1  is a detecting section in which, for example, when acceleration in the fourth direction DR 4  is applied, the movable electrodes  24  are displaced in the third direction DR 3 , whereby the opposing area between the movable electrodes  24  and the fixed electrodes  14  decreases and capacitance between the movable electrodes  24  and the fixed electrodes  14  decreases. The detecting section Z 2  is a detecting section in which, for example, when acceleration in the third direction DR 3  is applied, the movable electrodes  64  are displaced in the fourth direction DR 4 , whereby the opposing area between the movable electrodes  64  and the fixed electrodes  54  decreases and capacitance between the movable electrodes  64  and the fixed electrodes  54  decreases. That is, in the detecting section Z 1 , the capacitance decreases according to the acceleration in the fourth direction DR 4 . In the detecting section Z 2 , the capacitance decreases according to the acceleration in the third direction DR 3 . For example, as shown in  FIG.  3   , in the detecting section Z 1 , the thickness of the movable electrodes  24  in the third direction DR 3  is larger than the thickness of the fixed electrodes  14 . As shown in  FIG.  4   , in the detecting section Z 2 , the thickness of the movable electrodes  64  in the third direction DR 3  is smaller than the thickness of the fixed electrodes  54 . 
     In  FIG.  7   , the detecting section Z 1  is disposed in a first region R 1  and the detecting section Z 2  is disposed in a second region R 2  in the disposition region of the first movable electrode section  20  and the first fixed electrode section  10 . The detecting section Z 2  is disposed in a third region R 3  and the detecting section Z 1  is disposed in a fourth region R 4  in the disposition region of the second movable electrode section  60  and the second fixed electrode section  50 . 
     Therefore, in  FIG.  7   , when the first movable electrode section  20  and the second movable electrode section  60  are displaced in the third direction DR 3  by, for example, acceleration in the fourth direction DR 4 , capacitance between the first movable electrode section  20  and the first fixed electrode section  10  disposed in the first region R 1  in the disposition region of the first movable electrode section  20  and the first fixed electrode section  10  decreases. Capacitance between the second movable electrode section  60  and the second fixed electrode section  50  disposed in the fourth region R 4  in the disposition region of the second movable electrode section  60  and the second fixed electrode section  50  decreases. 
     That is, as shown in  FIG.  7   , in the first region R 1 , the detecting section Z 1  in which the opposing area between the first movable electrode section  20  and the first fixed electrode section  10  decreases when the first movable electrode section  20  changes in the third direction DR 3  is disposed. The detecting section Z 1  in which the thickness of the movable electrodes  24  in the third direction DR 3  is larger than the thickness of the fixed electrodes  14 , for example, as shown in  FIG.  3    is disposed. Therefore, when the first movable electrode section  20  changes in the third direction DR 3 , the capacitance between the first movable electrode section  20  and the first fixed electrode section  10  disposed in the first region R 1  decreases. The detecting section Z 1  in which the opposing area between the second movable electrode section  60  and the second fixed electrode section  50  decreases when the second movable electrode section  60  changes in the third direction DR 3  is disposed in the fourth region R 4 . Therefore, when the second movable electrode section  60  changes in the third direction DR 3 , the capacitance between the second movable electrode section  60  and the second fixed electrode section  50  disposed in the fourth region R 4  decreases. 
     On the other hand, for example, when the first movable electrode section  20  and the second movable electrode section  60  are displaced in the fourth direction DR 4 , which is the opposite direction of the third direction DR 3 , by, for example, acceleration in the third direction DR 3 , capacitance between the first movable electrode section  20  and the first fixed electrode section  10  disposed in the second region R 2  in the disposition region of the first movable electrode section  20  and the first fixed electrode section  10  decreases. Capacitance between the second movable electrode section  60  and the second fixed electrode section  50  disposed in the third region R 3  in the disposition region of the second movable electrode section  60  and the second fixed electrode section  50  decreases. 
     That is, as shown in  FIG.  7   , the detecting section Z 2  in which the opposing area between the first movable electrode section  20  and the first fixed electrode section  10  decreases when the first movable electrode section  20  changes in the fourth direction DR 4  is disposed in the second region R 2 . The detecting section Z 2  in which the thickness of the movable electrodes  24  in the third direction DR 3  is smaller than the thickness of the fixed electrodes  14 , for example, as shown in  FIG.  4    is disposed. Therefore, when the first movable electrode section  20  changes in the fourth direction DR 4 , the capacitance between the first movable electrode section  20  and the first fixed electrode section  10  disposed in the second region R 2  decreases. The detecting section Z 2  in which the opposing area between the second movable electrode section  60  and the second fixed electrode section  50  decreases when the second movable electrode section  60  changes in the fourth direction DR 4  is disposed in the third region R 3 . Therefore, when the second movable electrode section  60  changes in the fourth direction DR 4 , the capacitance between the second movable electrode section  60  and the second fixed electrode section  50  disposed in the third region R 3  decreases. 
     Consequently, by detecting, for example, the decrease in the capacitance between the first movable electrode section  20  and the first fixed electrode section  10  in the first region R 1  where the detecting section Z 1  is disposed and the decrease in the capacitance between the second movable electrode section  60  and the second fixed electrode section  50  in the fourth region R 4  where the detecting section Z 1  is disposed, it is possible to detect that the first movable electrode section  20  and the second movable electrode section  60  are displaced in the third direction DR 3  by, for example, acceleration in the fourth direction DR 4 . By detecting, for example, the decrease in the capacitance between the first movable electrode section  20  and the first fixed electrode section  10  in the second region R 2  where the detecting section Z 2  is disposed and the decrease in the capacitance between the second movable electrode section  60  and the second fixed electrode section  50  in the third region R 3  where the detecting section Z 2  is disposed, it is possible to detect that the first movable electrode section  20  and the second movable electrode section  60  are displaced in the fourth direction DR 4  by, for example, acceleration in the third direction DR 3 . 
     As shown in  FIGS.  3  and  4   , when the thicknesses of the movable electrodes  24  and  64  in the third direction DR 3  are differentiated in the detecting section Z 1  and the detecting section Z 2 , in  FIG.  7   , the detecting sections Z 1  and Z 2  are respectively disposed in the first region R 1  and the second region R 2  of the first movable body and the detecting sections Z 2  and Z 1  are respectively disposed in the third region R 3  and the fourth region R 4  of the second movable body. Specifically, the detecting section Z 1  in the first region R 1  and the detecting section Z 1  in the fourth region R 4  are point-symmetrically disposed and the detecting section Z 2  in the second region R 2  and the detecting section Z 2  in the third region R 3  are point-symmetrically disposed, for example, with respect to the vicinity of the center of the physical quantity sensor  1 . Therefore, it is possible to equalize the mass of the first movable body including the first movable electrode section  20  and the mass of the second movable body including the second movable electrode section  60 . There is an advantage that a mass balance of the movable bodies is good. 
     In  FIG.  7   , the first region R 1  and the second region R 2  are regions arranged side by side in the first direction DR 1  in the disposition region of the first movable electrode section  20  and the first fixed electrode section  10 . The third region R 3  and the fourth region R 4  are regions arranged side by side in the first direction DR 1  in the disposition region of the second movable electrode section  60  and the second fixed electrode section  50 . 
     Consequently, for example, when the first movable body and the second movable body move, for example, in the first direction DR 1 , which is the other axis direction, capacitance in the first region R 1  where the detecting section Z 1  is disposed decreases and, on the other hand, capacitance in the second region R 2  where the detecting section Z 2  is disposed increases. Therefore, changes in the capacitance are offset and deterioration in the other axis sensitivity can be suppressed. Capacitance in the third region R 3  where the detecting section Z 2  is disposed decreases and, on the other hand, capacitance in the fourth region R 4  where the detecting section Z 1  is disposed increases. Therefore, changes in the capacitance are offset and deterioration in the other axis sensitivity can be suppressed. 
     In  FIG.  7   , the detecting sections are disposed in the order of the detecting sections Z 1 , Z 2 , Z 2 , and Z 1  in the first direction DR 1 . However, the detecting sections may be disposed in the order of, for example, the detecting sections Z 2 , Z 1 , Z 1 , and Z 2  in the first direction DR 1 . 
     Another configuration example of the physical quantity sensor  1  is shown in  FIG.  8   .  FIG.  8    is different from  FIG.  7    in the positions of the fixed sections  3  and  4  of the first fixed electrode section  10 . In  FIG.  7   , the fixed sections  3  and  4  are disposed on the opposite direction side of the second direction DR 2  with respect to the first fixed electrode section  10 . In  FIG.  8   , the fixed sections  3  and  4  are disposed on the second direction DR 2  side with respect to the first fixed electrode section  10 . Consequently, both of the fixed sections  3  and  4  of the first fixed electrode section  10  and the fixed sections  5  and  6  of the second fixed electrode section  50  are disposed on the second direction DR 2  side. Therefore, it is possible to draw out, to the same second direction DR 2  side, electrode wires for fixed electrodes extending from the fixed sections  3  and  4  and electrode wires for fixed electrodes extending from the fixed sections  5  and  6 . It is possible to efficiently wire the electrode wires. 
     Another configuration example of the physical quantity sensor  1  is shown in  FIG.  9   . In  FIG.  9   , the first region R 1  and the second region R 2  are regions arranged side by side in the second direction DR 2  in the disposition region of the first movable electrode section  20  and the first fixed electrode section  10 . The third region R 3  and the fourth region R 4  are regions arranged side by side in the second direction DR 2  in the disposition region of the second movable electrode section  60  and the second fixed electrode section  50 . With such disposition, for example, in the detecting sections Z 1  and Z 2  in the first element section  91  and the second element section  92 , changes in the capacitance can be offset. Deterioration in the other axis sensitivity can be suppressed. 
     In  FIGS.  7 ,  8 , and  9   , the first movable electrode section  20  includes the first base movable electrode  23 , the first movable electrodes  21  extending in the first direction DR 1  from the first base movable electrode  23 , and the second movable electrodes  22  extending in the opposite direction of the first direction DR 1  from the first base movable electrode  23 . The first fixed electrode section  10  includes the first fixed electrodes  11  opposed to the first movable electrodes  21  and the second fixed electrodes  12  opposed to the second movable electrodes  22 . The second movable electrode section  60  includes the second base movable electrode  63 , the third movable electrodes  61  extending in the first direction DR 1  from the second base movable electrode  63 , and the fourth movable electrodes  62  extending in the opposite direction of the first direction DR 1  from the second base movable electrode  63 . The second fixed electrode section  50  includes the third fixed electrodes  51  opposed to the third movable electrodes  61  and the fourth fixed electrodes  52  opposed to the fourth movable electrodes  62 . 
     Consequently, when a physical quantity such as acceleration, for example, in the first direction DR 1 , which is the other axis direction, changes, for example, one opposing area of the opposing area between the first movable electrodes  21  and the first fixed electrodes  11  and the opposing area between the second movable electrodes  22  and the second fixed electrodes  12  decreases and the other opposing area increases. One opposing area of the opposing area between the third movable electrodes  61  and the third fixed electrodes  51  and the opposing area between the fourth movable electrodes  62  and the fourth fixed electrodes  52  decreases and the other opposing area increases. Therefore, changes in the opposing areas can be offset when the physical quantity such as acceleration in the other axis direction changes. Deterioration in the other axis sensitivity can be suppressed. 
     In  FIGS.  7 ,  8 , and  9   , as in  FIG.  6   , electrode disposition may be adopted in which the fixed electrodes are extended to both sides from the base fixed electrode to be opposed to the movable electrodes corresponding to the fixed electrodes. 
     3. Inertial Measurement Device 
     Subsequently, an example of an inertial measurement device  2000  in this embodiment is explained with reference to  FIGS.  10  and  11   . The inertial measurement device  2000  (IMU: Inertial Measurement Unit) shown in  FIG.  10    is a device that detects inertial momentum such as a posture or a behavior of a moving body such as an automobile or a robot. The inertial measurement device  2000  is a so-called six-axis motion sensor including an acceleration sensor that detects accelerations ax, ay, and az in directions extending along three axes and an angular velocity sensor that detects angular velocities ωx, ωy, and ωz around the three axes. 
     The inertial measurement device  2000  is a rectangular parallelepiped, a plane shape of which is a substantial square. Screw holes  2110  functioning as mount sections are formed near vertexes in two places located in a diagonal direction of the square. The inertial measurement device  2000  can be fixed to a mount surface of a mount body such as an automobile by inserting two screws through the screw holes  2210  in the two places. The inertial measurement device  2000  can also be reduced to a size mountable on a smartphone or a digital camera through selection of components and a design change. 
     The inertial measurement device  2000  includes an outer case  2100 , a joining member  2200  and a sensor module  2300 . The sensor module  2300  is inserted into the inside of the outer case  2100  with the joining member  2200  interposed. The sensor module  2300  includes an inner case  2310  and a circuit board  2320 . A recess  2311  for preventing contact with the circuit board  2320  and an opening  2312  for exposing a connector  2330  explained below are formed in the inner case  2310 . The circuit board  2320  is joined to the lower surface of the inner case  2310  via an adhesive. 
     As shown in  FIG.  11   , a connector  2330 , an angular velocity sensor  2340   z  that detects angular velocity around the Z axis, an acceleration sensor unit  2350  that detects accelerations in axial directions of the X axis, the Y axis, and the Z axis, and the like are mounted on the upper surface of the circuit board  2320 . An angular velocity sensor  2340   x  that detects angular velocity around the X axis and an angular velocity sensor  2340   y  that detects angular velocity around the Y axis are mounted on a side surface of the circuit board  2320 . 
     The acceleration sensor unit  2350  includes at least the physical quantity sensor  1  for measuring acceleration in the Z-axis direction explained above and can detect acceleration in one axial direction or detect accelerations in two axial directions or three axial directions according to necessity. The angular velocity sensors  2340   x ,  2340   y , and  2340   z  are not particularly limited. For example, a vibration gyro sensor that makes use of the Coriolis force can be used as the angular velocity sensors  2340   x ,  2340   y , and  2340   z.    
     A control IC  2360  is mounted on the lower surface of the circuit board  2320 . The control IC  2360  functioning as a control section that performs control based on a detection signal output from the physical quantity sensor  1  is, for example, an MCU (Micro Controller Unit). The control IC  2360  incorporates a storing section including a nonvolatile memory, an A/D converter, and the like and controls the sections of the inertial measurement device  2000 . Besides, a plurality of electronic components are mounted on the circuit board  2320 . 
     As explained above, the inertial measurement device  2000  in this embodiment includes the physical quantity sensor  1  and the control IC  2360  functioning as the control section that performs control based on a detection signal output from the physical quantity sensor  1 . With the inertial measurement device  2000 , since the acceleration sensor unit  2350  including the physical quantity sensor  1  is used, it is possible to provide the inertial measurement device  2000  that can enjoy the effects of the physical quantity sensor  1  and realize improvement of accuracy and the like. 
     The inertial measurement device  2000  is not limited to the configuration shown in  FIGS.  10  and  11   . For example, in the inertial measurement device  2000 , a configuration may be adopted in which the angular velocity sensors  2340   x ,  2340   y , and  2340   z  are not provided and only the physical quantity sensor  1  is provided as an inertial sensor. In this case, for example, the inertial measurement device  2000  only has to be realized by housing the physical quantity sensor  1  and the control IC  2360 , which realizes the control section, in a package, which is a housing container. 
     As explained above, a physical quantity sensor in an embodiment includes: a first fixed electrode section and a second fixed electrode section provided on a substrate; a first movable electrode section provided such that a movable electrode is opposed to a fixed electrode of the first fixed electrode section; and a second movable electrode section provided such that a movable electrode is opposed to a fixed electrode of the second fixed electrode section. The physical quantity sensor includes: a first fixed section and a second fixed section fixed to the substrate; a first support beam, one end of which is coupled to the first fixed section; a first coupling section configured to couple another end of the first support beam and the first movable electrode section; a second support beam, one end of which is coupled to the second fixed section; and a second coupling section configured to couple another end of the second support beam and the second movable electrode section. When three directions orthogonal to one another are represented as a first direction, a second direction, and a third direction, in a plane view in the third direction orthogonal to the substrate, the first movable electrode section, the second fixed section, the first fixed section, and the second movable electrode section are disposed side by side in the first direction in order of the first movable electrode section, the second fixed section, the first fixed section, and the second movable electrode section. 
     With the physical quantity sensor having such a configuration, the second fixed section can be disposed using a space between the first fixed section and the first movable electrode section. The first fixed section can be disposed using a space between the second fixed section and the second movable electrode section. Therefore, the first movable electrode section, the second fixed section, the first fixed section, and the second movable electrode section can be compactly disposed side by side in the first direction. A reduction in the size of the physical quantity sensor can be realized. The first fixed section and the second fixed section can be disposed close to each other. Deterioration in accuracy due to the influence of a warp of the substrate or the like of the physical quantity sensor can be minimized. Both of the reduction in the size and improvement of accuracy of the physical quantity sensor can be realized. 
     In the embodiment, the movable electrode of the first movable electrode section and the fixed electrode of the first fixed electrode section may be opposed in the second direction, and the movable electrode of the second movable electrode section and the fixed electrode of the second fixed electrode section may be opposed in the second direction. 
     Consequently, for example, it is possible to detect a change in capacitance due to a change in an opposing area between the first movable electrode section and the first fixed electrode section and a change in capacitance due to a change in an opposing area between the second movable electrode section and the second fixed electrode section and measure a physical quantity. 
     In the embodiment, the first movable electrode section may include a first base movable electrode, a first movable electrode extending in the first direction from the first base movable electrode, and a second movable electrode extending in an opposite direction of the first direction from the first base movable electrode, and the first fixed electrode section may include a first fixed electrode opposed to the first movable electrode and a second fixed electrode opposed to the second movable electrode. 
     Consequently, when a physical quantity changes in the other axis direction, for example, one opposing area of an opposing area between the first movable electrode and the first fixed electrode and an opposing area between the second movable electrode and the second fixed electrode decreases and the other opposing area increases. For example, deterioration in other axis sensitivity can be suppressed. 
     In this embodiment, the second movable electrode section may include a second base movable electrode, a third movable electrode extending in the first direction from the second base movable electrode, and a fourth movable electrode extending in an opposite direction of the first direction from the second base movable electrode, and the second fixed electrode section may include a third fixed electrode opposed to the third movable electrode and a fourth fixed electrode opposed to the fourth movable electrode. 
     Consequently, when a physical quantity changes in the other axis direction, for example, one opposing area of an opposing area between the third movable electrode and the third fixed electrode and an opposing area between the fourth movable electrode and the fourth fixed electrode decreases and the other opposing area increases. For example, deterioration in other axis sensitivity can be suppressed. 
     In this embodiment, the first fixed electrode section may include a first base fixed electrode, a first fixed electrode extending in the first direction from the first base fixed electrode, and a second fixed electrode extending in an opposite direction of the first direction from the first base fixed electrode, and the first movable electrode section may include a first movable electrode opposed to the first fixed electrode and a second movable electrode opposed to the second fixed electrode. 
     Consequently, when a physical quantity changes in the other axis direction, for example, one opposing area of an opposing area between the first movable electrode and the first fixed electrode and an opposing area between the second movable electrode and the second fixed electrode decreases and the other opposing area increases. For example, deterioration in other axis sensitivity can be suppressed. 
     In this embodiment, the second fixed electrode section may include a second base fixed electrode, a third fixed electrode extending in the first direction from the second base fixed electrode, and a fourth fixed electrode extending in an opposite direction of the first direction from the second base fixed electrode, and the second movable electrode section may include a third movable electrode opposed to the third fixed electrode and a fourth movable electrode opposed to the fourth fixed electrode. 
     Consequently, when a physical quantity changes in the other axis direction, for example, one opposing area of an opposing area between the third movable electrode and the third fixed electrode and an opposing area between the fourth movable electrode and the fourth fixed electrode decreases and the other opposing area increases. For example, deterioration in other axis sensitivity can be suppressed. 
     In this embodiment, when the first movable electrode section and the second movable electrode section are displaced in the third direction, capacitance between the first movable electrode section and the first fixed electrode section may decrease and, when the first movable electrode section and the second movable electrode section are displaced in a fourth direction, which is an opposite direction of the third direction, capacitance between the second movable electrode section and the second fixed electrode section may decrease. 
     Consequently, by detecting, for example, a decrease in the capacitance between the first movable electrode section and the first fixed electrode section, it is possible to detect that the first movable electrode section and the second movable electrode section are displaced in the third direction. By detecting, for example, a decrease in the capacitance between the second movable electrode section and the second fixed electrode section, it is possible to detect that the first movable electrode section and the second movable electrode section are displaced in the fourth direction. 
     In this embodiment, when the first movable electrode section and the second movable electrode section are displaced in the third direction, capacitance between the first movable electrode section and the first fixed electrode section disposed in a first region in a disposition region of the first movable electrode section and the first fixed electrode section may decrease and capacitance between the second movable electrode section and the second fixed electrode section disposed in a fourth region in a disposition region of the second movable electrode section and the second fixed electrode section may decrease. When the first movable electrode section and the second movable electrode section are displaced in a fourth direction, which is an opposite direction of the third direction, capacitance between the first movable electrode section and the first fixed electrode section disposed in a second region in the disposition region of the first movable electrode section and the first fixed electrode section may decrease and capacitance between the second movable electrode section and the second fixed electrode section disposed in a third region in the disposition region of the second movable electrode section and the second fixed electrode section may decrease. 
     Consequently, by detecting, for example, a decrease in the capacitance between the first movable electrode section and the first fixed electrode section in the first region or a decrease in the capacitance between the second movable electrode section and the second fixed electrode section in the fourth region, it is possible to detect that the first movable electrode section and the second movable electrode section are displaced in the third direction. By detecting, for example, a decrease in the capacitance between the first movable electrode section and the first fixed electrode section in the second region or a decrease in the capacitance between the second movable electrode section and the second fixed electrode section in the third region, it is possible to detect that the first movable electrode section and the second movable electrode section are displaced in the fourth direction. 
     In this embodiment, the first region and the second region may be regions arranged side by side in the first direction in the disposition region of the first movable electrode section and the first fixed electrode section, and the third region and the fourth region may be regions arranged side by side in the first direction in the disposition region of the second movable electrode section and the second fixed electrode section. 
     Consequently, for example, when the first movable electrode section and the second movable electrode section move in the other axis direction, the capacitance in the first region decreases and, on the other hand, the capacitance in the second region increases. Therefore, changes in the capacitance are offset and, for example, deterioration in the other axis sensitivity can be suppressed. The capacitance in the third region decreases and, on the other hand, the capacitance in the fourth region increases. Therefore, changes in the capacitance are offset and, for example, deterioration in the other axis sensitivity can be suppressed. 
     In this embodiment, the first region and the second region may be regions arranged side by side in the second direction in the disposition region of the first movable electrode section and the first fixed electrode section, and the third region and the fourth region may be regions arranged side by side in the second direction in the disposition region of the second movable electrode section and the second fixed electrode section. 
     With such disposition as well, changes in the capacitance can be offset and, for example, deterioration in the other axis sensitivity can be suppressed, for example, in detecting sections in element sections. 
     In this embodiment, the first movable electrode section may include a first base movable electrode, a first movable electrode extending in the first direction from the first base movable electrode, and a second movable electrode extending in an opposite direction of the first direction from the first base movable electrode, and the first fixed electrode section may include a first fixed electrode opposed to the first movable electrode and a second fixed electrode opposed to the second movable electrode. The second movable electrode section may include a second base movable electrode, a third movable electrode extending in the first direction from the second base movable electrode, and a fourth movable electrode extending in the opposite direction of the first direction from the second base movable electrode, and the second fixed electrode section may include a third fixed electrode opposed to the third movable electrode and a fourth fixed electrode opposed to the fourth movable electrode. 
     Consequently, when a physical quantity in the other axis direction changes, for example, one opposing area of an opposing area between the first movable electrode and the first fixed electrode and an opposing area between the second movable electrode and the second fixed electrode decreases and the other opposing area increases. One opposing area of an opposing area between the third movable electrode and the third fixed electrode and an opposing area of the fourth movable electrode and the fourth fixed electrode decreases and the other opposing area increases. For example, deterioration in the other axis sensitivity can be suppressed. 
     In this embodiment, in the plane view, the first movable electrode section, the second fixed section and the second support beam, the first fixed section and the first support beam, and the second movable electrode section may be disposed side by side in the first direction in order of the first movable electrode section, the second fixed section and the second support beam, the first fixed section and the first support beam, and the second movable electrode section. 
     Consequently, the second fixed section and the second support beam can be disposed using a space between the first fixed section and the first support beam and the first movable electrode section. The first fixed section and the first support beam can be disposed using a space between the second fixed section and the second support beam and the second movable electrode section. For example, a reduction in the size of the physical quantity sensor can be realized. 
     This embodiment relates to an inertial measurement device including: the physical quantity sensor described above; and a control section configured to perform control based on a detection signal output from the physical quantity sensor. 
     As explained above, this embodiment is explained in detail. However, it would be easily understood by those skilled in the art that many modifications not substantially departing from the new matters and the effects of the present disclosure are possible. Therefore, all of such modifications are deemed to be included in the scope of the present disclosure. For example, terms described together with broader-sense or synonymous different terms at least once in the specification or the drawings can be replaced with the different terms in any place of the specification or the drawings. All combinations of this embodiment and the modifications are included in the scope of the present disclosure. The configurations, the operations, and the like of the physical quantity sensor and the inertial measurement device are not limited to the configurations, the operations, and the like explained in this embodiment. Various modified implementations are possible.