Patent Publication Number: US-2010116051-A1

Title: Angular velocity sensor

Description:
TECHNICAL FIELD 
     The present invention relates to an angular velocity sensor that detects an angular velocity for use in a variety of electronic devices for postural control and navigation of moving bodies such as aircraft, automobiles, robots, ships, and vehicles. 
     BACKGROUND ART 
     In the following, a conventional angular velocity sensor is described. The conventional angular velocity sensor generally oscillates a detection element in a variety of shapes, such as tuning-fork shape, H-shape or T-shape, and electrically detects distortion of the detection element accompanied by generation of Coriolis force. In that case, in an X axis, a Y axis and a Z axis which are substantially orthogonal to one another, when a vehicle is arranged on an XY plane of the X axis and the Y axis, an angular velocity sensor for a navigation device needs to detect an angular velocities around the X axis and around the Z axis of the vehicle. Conventionally, in the case of detecting angular velocities of a plurality of detection axes (X axis, Y axis, Z axis), a plurality of angular velocity sensors have been used to correspond to the number of detection axes. Further, for detecting an angular velocity around the Z axis, a detection element has been used as erectingly provided with respect to the XY plane. As for prior art document information related to an invention of this application, for example, Patent Document 1 is known. 
     However, in the above configuration, there has been a problem that in the case of detecting angular velocities of a plurality of detection axes, it is necessary to ensure a mounting area for mounting a plurality of detection elements and a plurality of angular velocity sensors on a mounting substrate correspondingly to the respective detection axes, and reduction in size of a variety of electronic devices cannot be sought. 
     [Patent Document 1] Unexamined Japanese Patent Publication No. 2001-208546 
     DISCLOSURE OF THE INVENTION 
     The present invention has: a detection element, which has a sensing section arranged in a flexible body and sensing distortion of the flexible body; and a detection circuit section, which detects an angular velocity relating to the detection element. The sensing section has a sensing electrode section made up of an upper electrode and a lower electrode with a piezoelectric body interposed therebetween. The detection circuit section detects an angular velocity based upon angular velocity signals outputted from the sensing electrode section in accordance with the angular velocity. It is configured such that the angular velocity signals include an X component signal around the X axis and a Z component signal around the Z axis in mutually orthogonal X axis, Y axis and Z axis, and the detection circuit section is provided with a separation circuit that separates the X component signal and the Z component signal. 
     With this configuration, since the angular velocity signals include the X component signal around the X axis and the Z component signal around the Z axis in mutually orthogonal X axis, Y axis and Z axis, and the detection circuit section is provided with the separation circuit that separates the X component signal and the Z component signal, angular velocities around a plurality of detection axes can be detected in one detection element. Therefore, in the case of detecting angular velocities of the plurality of detection axes, a mounting area for mounting a plurality of detection elements and a plurality of angular velocity sensors is not needed ensuring, but a mounting area for mounting only one detection element may be ensured, and hence it is possible to seek reduction in size of a variety of electronic devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a detection element of an angular velocity sensor according to an embodiment of the present invention; 
         FIG. 2  is a schematic sectional view along A-A of  FIG. 1 ; and 
         FIG. 3  is a view of an operational condition of a detection element. 
     
    
    
     REFERENCE MARKS IN THE DRAWINGS 
     
         
           1  Detection element 
           2  First arm 
           4  Second arm 
           6  Supporting section 
           8  Frame body 
           11  Weight section 
           12  Groove section 
           13  Piezoelectric body 
           14  Lower electrode 
           15  Upper electrode 
           17  Driving section 
           17   a  First driving electrode section 
           17   b  First driving electrode section 
         First sensing section 
           19   a  First sensing electrode section 
           19   b  First sensing electrode section 
           20  Second sensing section 
           20   a  Second sensing electrode section 
           20   b  Second sensing electrode section 
           21  Third sensing section 
           21   a  Third sensing electrode section 
           21   b  Third sensing electrode section 
       
    
     PREFERRED EMBODIMENTS FOR CARRYING OUT OF THE INVENTION 
       FIG. 1  is a perspective view of a detection element of an angular velocity sensor in an embodiment of the present invention. In  FIG. 1 , the angular velocity sensor according to an embodiment of the present invention has detection element  1  that detects an angular velocity, and its base is made of a platy flexible body. Detection element  1  has two orthogonal arms each formed by coupling first arm  2  to second arm  4  in a substantially orthogonal direction. One end of the two first arms  2  are supported by supporting section  6 , and the other ends of the two first arms  2  are coupled to frame body  8 , and the arms are fixed to a mounting substrate (not shown) with this frame body  8 . Further, second arm  4  is bent into a U-shape to provide opposing sections  16  opposed to second arm  4  itself, and weight section  11  is coupled to the end of the opposing section  16 . This weight section  11  is provided with groove section  12 , and the end portion of second arm  4  is coupled to groove section  12 . 
     In this detection element  1 , first arm  2  and supporting section  6  are arranged on substantially the same straight line, and when the space is defined by a Z axis vertical to the surface of detection element  1 , and an X axis and a Y axis that are orthogonal to the Z axis and orthogonal to each other, in the case of arranging first arm  2  in the X-axis direction, second arm  4  is arranged in the Y axis direction. 
     Further, driving section  17  that drives and oscillates weight section  11  is provided on the surface of any one of second arm out of four second arms  4 , and on the surfaces of the other second arms  4 , first sensing section  19 , second sensing section  20  and third sensing section  21  which sense distortion of second arms  4  are provided. 
     Driving section  17  has electrode sections sandwiching, from above and below, piezoelectric body (not shown) for driving weight section  11  of second arm  4 . First driving electrode section  17   a  is arranged on the internal peripheral section of any one of second arms  4 , and first driving electrode section  17   b  is also arranged on the outer peripheral side thereof. Further, first driving electrode sections  17   a ,  17   b  are arranged as opposed to each other. 
     First sensing section  19 , second sensing section  20  and third sensing section  21  are electrode sections respectively sandwiching, from above and below, piezoelectric bodies  13  (not shown) for sensing distortion of second arms  4 . In the three second arms  4 , on the inner peripheral section sides thereof, first sensing electrode section  19   a , second sensing electrode section  20   a  and third sensing electrode section  21   a  are respectively arranged, and also on the outer peripheral section sides, first sensing electrode section  19   b , second sensing electrode section  20   b  and third sensing electrode section  21   b  are respectively arranged. Further, first sensing electrode sections  19   a ,  19   b  are arranged as opposed to each other, second sensing electrode sections  20   a ,  20   b  are arranged as opposed to each other, third sensing electrode sections  20   a ,  20   b  are arranged as opposed to each other. 
     The electrode sections sandwiching the piezoelectric body (not shown) from above and below are made up of lower electrode  14  and upper electrode  15 . Signal lines are drawn respectively from lower electrodes  14  and upper electrodes  15  of first driving electrode sections  17   a ,  17   b , and lower electrodes  14  and upper electrodes  15  of first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b.    
       FIG. 2  is a schematic sectional view along A-A of  FIG. 1 . As shown in  FIG. 2 , the signal lines drawn from first driving electrode sections  17   a ,  17   b , first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b , and the respective electrode sections may each be formed by forming lower electrode  14  made of Pt on second arm  4  made up of a silicon substrate by high-frequency sputtering, forming piezoelectric body  13  made of PZT on top of this lower electrode  14  by high-frequency sputtering, and vapor depositing upper electrode  15  made of Au on top of piezoelectric body  13  made of PZT. 
       FIG. 3  is an operational state view of detection element  1 . A case is considered where the space is defined by a Z axis vertical to the surface of detection element  1 , and an X axis and a Y axis that are orthogonal to the Z axis and orthogonal to each other, first arm  2  of detection element  1  is arranged in the X-axis direction, and second arm  4  is arranged in the Y axis direction. When an alternating voltage of a resonance frequency is applied to first driving electrode sections  17   a ,  17   b , second arm  4  is driven and oscillated starting from second arm  4  where driving section  17  is arranged, based upon which weight section  11  is also driven and oscillated in a direction opposed to second arm  4  (driving and oscillating direction D indicated by a solid-line arrow and a dotted-line arrow). Further, all of the four second arms  4  and the four weight sections  11  are synchronously driven and oscillated in the direction opposed to second arm  4 . This driving and oscillating direction in detection element  1  becomes the X axis direction. 
     At this time, for example when an angular velocity occurs counterclockwise around the Z axis, Coriolis force is generated on weight section  11  in a direction orthogonal to the driving and oscillating direction (Coriolis direction C indicated by a solid-line arrow and a dotted-line arrow) synchronously with the driving and oscillation of weight section  11 , and hence distortion can be generated due to the angular velocity counterclockwise around the Z axis of second arm  4 . This Coriolis direction in detection element  1  becomes the Y axis direction. 
     When the Coriolis force is generated in the Coriolis direction C indicated by the solid arrow, in second arms  4  provided with first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b , first sensing electrode section  19   a , second sensing electrode section  20   b  and third sensing electrode section  21   a  sense shrinkage of second arms  4 . Simultaneously, first sensing electrode section  19   b , second sensing electrode section  20   a  and third sensing electrode section  21   b  sense extension of second arms  4 . When the Coriolis force is generated in the Coriolis direction indicated by the dotted-line arrow, extension and shrinkage in a direction opposite thereto are sensed. In accordance with the sensed extension and shrinkage, angular velocity signals are outputted from first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b , to detect the angular velocity. 
     Meanwhile, on the contrary to the above, in the case of occurrence of an angular velocity clockwise around the Z axis, second arm  4  is extended and shrunk in a direction directly opposite to the case of occurrence of an angular velocity counterclockwise around the Z axis, and first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b  sense this extension and shrinkage, to detect the angular velocity. 
     Further, also in the case of occurrence of an angular velocity around the X axis or the Y axis, the Coriolis force is generated on weight section  11  in a direction orthogonal to the driving and oscillating direction synchronously with the driving and oscillation of weight section  11 , and hence distortion is generated due to the angular velocity around the Y axis of second arm  4 , and first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b  sense extension and shrinkage of second arms  4 , to detect the angular velocity. 
     Next, angular velocity detection processing of the angular velocity sensor is described. First sensing section  19 , second sensing section  20  and third sensing section  21  arranged in second arms  4  are connected to a detection circuit section, and in this detection circuit section, an angular velocity is detected based upon angular velocity signals outputted from lower electrodes  14  and upper electrodes  15  of first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b . The angular velocity signals include an X component signal around the X axis, a Y component signal around the Y axis, a Z component signal around the Z axis and an oscillating component signal of a flexible body in the mutually orthogonal X axis, Y axis and Z axis. The detection circuit section is provided with a separation circuit that separates these X component signal, Y component signal, Z component signal and the oscillating component signal. 
     Since first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b  have almost the same area, absolute values of the X component signal, the Y component signal, the Z component signal and the oscillating component signal which are detected in the respective electrodes are equivalent to one another. Hence in the separation circuit, the signals can be increased or offset by adding or subtracting outputs of the respective electrodes. A signal values obtained by this addition or subtraction is referred to as a sum/difference signal value. This enables separation of each component signal. Further, as shown in  FIG. 1 , with third sensing electrode sections  19   a  and  20   a  being located symmetrically about a plane vertical to the X axis, the offset is facilitated. This also applies to the relationship between third sensing electrode sections  19   b  and  20   b . Moreover, with third sensing electrode section  20   a  and third sensing electrode section  21   a  being located symmetrically about a plane vertical to the Y axis, the offset is facilitated. This also applies to the relationship between third sensing electrode section  20   b  and third sensing electrode section  21   b . Furthermore, with third sensing electrode section  19   a  and third sensing electrode section  19   b  being arrayed in pairs, the offset is facilitated. This also applies to third sensing electrode section  20   a  and third sensing electrode section  20   b . This also applies to third sensing electrode section  21   a  and third sensing electrode section  21   b . On the whole, as shown in  FIG. 1 , in detection element  1 , the shapes of weight sections  11  and the like are symmetrical about supporting section  6  being the central position of detection element  1  taken as the center, thereby facilitating offset of a variety of output signals. 
     The X component signal is detected based upon a sum/difference signal value of the X component signal in a combination of a sum/difference signal value of the X component signal being not 0 and a sum/difference signal value of the Y component signal, a sum/difference signal value of the Z component signal and a sum/difference signal value of the oscillating component signal being 0 in first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b . The Y component signal is detected based upon a sum/difference signal value of the Y component signal in a combination of a sum/difference signal value of the Y component signal being not 0 and a sum/difference signal value of the X component signal, a sum/difference signal value of the Z component signal and a sum/difference signal value of the oscillating component signal being 0 in first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b . The Z component signal is detected based upon a sum/difference signal value of the Z component signal in a combination of a sum/difference signal value of the Z component signal being not 0 and a sum/difference signal value of the X component signal, a sum/difference signal value of the Y component signal and a sum/difference signal value of the oscillating component signal being 0 in first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b . In such a manner, the X component signal, the Y component signal, the Z component signal and the oscillating component signal are separated. 
     In comparison of the X component signal, the Y component signal, the Z component signal and the oscillating component signal as the angular velocity signals, the oscillating component signal is typically much larger than the other signals. When X component signal, the Y component signal, the Z component signal and the oscillating component signal, which are outputted from first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b  arranged in detection element  1 , are respectively referred to as an X value, Y value, Z value and D value, and for example, when assuming that the X value, the Y value and the Z value of the X component signal, the Y component signal and the Z component signal are “1” and the oscillating component signal is “10”, the X value, the Y value, the Z value and the D value in the respective signal values captured as peak values at a certain moment are as shown in TABLE 1. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 SIGNAL 
                   
                   
                   
                   
               
               
                 VALUE 
                 X VALUE 
                 Y VALUE 
                 Z VALUE 
                 D VALUE 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 19a 
                 −1 
                 −1 
                 1 
                 −10 
               
               
                 19b 
                 −1 
                 −1 
                 −1 
                 10 
               
               
                 20a 
                 −1 
                 1 
                 1 
                 10 
               
               
                 20b 
                 −1 
                 1 
                 −1 
                 −10 
               
               
                 21a 
                 1 
                 1 
                 −1 
                 10 
               
               
                 21b 
                 1 
                 1 
                 1 
                 −10 
               
               
                   
               
            
           
         
       
     
     Results of the sum/difference signal values at this time are shown in TABLE 2. 
     
       
         
           
               
               
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 SUM/ 
                 X 
                 Y 
                 Z 
                 D 
               
               
                   
                 DIFFERENCE 
                 VAL- 
                 VAL- 
                 VAL- 
                 VAL- 
               
               
                   
                 SIGNAL VALUE 
                 UE 
                 UE 
                 UE 
                 UE 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 FIRST 
                 21b − 21a 
                 0 
                 0 
                 2 
                 −20 
               
               
                 SECOND 
                 21b − 19b 
                 2 
                 2 
                 2 
                 −20 
               
               
                 THIRD 
                 21b − 19a 
                 2 
                 2 
                 0 
                 0 
               
               
                 FOURTH 
                 21b − 20b 
                 2 
                 0 
                 2 
                 0 
               
               
                 FIFTH 
                 21b − 20a 
                 2 
                 0 
                 0 
                 −20 
               
               
                 SIXTH 
                 21a − 19b 
                 2 
                 2 
                 0 
                 0 
               
               
                 SEVENTH 
                 21a − 19a 
                 2 
                 2 
                 0 
                 0 
               
               
                 EIGHTH 
                 21a − 20b 
                 2 
                 0 
                 0 
                 20 
               
               
                 NINTH 
                 21a − 20a 
                 2 
                 0 
                 −2 
                 0 
               
               
                 TENTH 
                 19b − 19a 
                 0 
                 0 
                 −2 
                 20 
               
               
                 ELEVENTH 
                 19b − 20b 
                 0 
                 −2 
                 0 
                 20 
               
               
                 TWELFTH 
                 19b − 20a 
                 0 
                 −2 
                 −2 
                 0 
               
               
                 THIRTEENTH 
                 19a − 20b 
                 0 
                 −2 
                 2 
                 0 
               
               
                 FOURTEENTH 
                 19a − 20a 
                 0 
                 −2 
                 0 
                 −20 
               
               
                 FIFTEENTH 
                 20b − 20a 
                 0 
                 0 
                 −2 
                 −20 
               
               
                 SIXTEENTH 
                 20a − 21b 
                 −2 
                 0 
                 0 
                 20 
               
               
                 SEVENTEENTH 
                 20a − 21a 
                 −2 
                 0 
                 2 
                 0 
               
               
                 EIGHTEENTH 
                 20a − 19b 
                 0 
                 2 
                 2 
                 0 
               
               
                 NINETEENTH 
                 20a − 19a 
                 0 
                 2 
                 0 
                 20 
               
               
                 TWENTIETH 
                 20a − 20b 
                 0 
                 0 
                 2 
                 20 
               
               
                 TWENTY-FIRST 
                 20b − 21b 
                 −2 
                 0 
                 −2 
                 0 
               
               
                 TWENTY-SECOND 
                 20b − 21a 
                 −2 
                 0 
                 0 
                 −20 
               
               
                 TWENTY-THIRD 
                 20b − 19b 
                 0 
                 2 
                 2 
                 −20 
               
               
                 TWENTY-FOURTH 
                 29b − 19a 
                 0 
                 2 
                 −2 
                 0 
               
               
                 TWENTY-FIFTH 
                 19a − 21b 
                 −2 
                 −2 
                 0 
                 0 
               
               
                 TWENTY-SIXTH 
                 19a − 21a 
                 −2 
                 −2 
                 2 
                 −20 
               
               
                 TWENTY-SEVENTH 
                 19a − 19b 
                 0 
                 0 
                 2 
                 −20 
               
               
                 TWENTY-EIGHTH 
                 19b − 21b 
                 −2 
                 −2 
                 −2 
                 20 
               
               
                 TWENTY-NINTH 
                 19b − 21b 
                 −2 
                 −2 
                 0 
                 0 
               
               
                 THIRTIETH 
                 21a − 21b 
                 0 
                 0 
                 −2 
                 20 
               
               
                   
               
            
           
         
       
     
     In TABLE 2, “ 21   b - 21   a ” first in the table shows difference signals of an X value, a Y value, a Z value and a D value of third sensing electrode section  21   b  and an X value, a Y value, a Z value and a D value of third sensing electrode section  21   a . The X value is “0”, the Y value is “0”, the Z value is “−2” and the D value is “−20”. Second to thirtieth difference values are shown in the same manner. 
     When sum/difference signal values are calculated from these difference values and combinations satisfying the above condition in the separation circuit are extracted, results are as follows. 
     As for the X component signal, difference signal values (X value: “8”, Y value: “0”, Z value: “0”, D value: “0”) of fourth and ninth sum signal values (X value: “4”, Y value: “0”, Z value: “0”, D value: “0”) and seventeenth and twenty-first sum signal values (X value: “−4”, Y value: “0”, Z value: “0”, D value: “0”) are most suitable for the separation. In both the fourth and ninth values and the seventeenth and twenty-first values, the sum/difference signal value of the X component signal is not 0 and the sum/difference signal value of the Z component signal is 0. Further, in both values, the sum/difference signal value of the Y component signal is 0. Moreover, in both values, the sum/difference signal value of the oscillating component signal is 0. In this calculation, when the respective signal values up to the thirtieth signal value in TABLE 2 are regarded as first-stage sum/difference signal values, the fourth and ninth sum signal values can be referred to as second-stage sum/difference signal values in accordance with the process of that calculation. The seventeenth and twenty-first sum signal values can also be referred to as second-stage sum/difference signal value. Further, a value obtained by calculating a sum/difference of the four values of the fourth and ninth values and the seventeenth and twenty-first values can be referred to as a third-stage sum/difference signal value in accordance with the process of that calculation. 
     As for the Y component signal, difference signal values (X value: “0”, Y value: “8”, Z value: “0”, D value: “0”) of twelfth and thirteenth sum signal values (X value: “0”, Y value: “−4”, Z value: “0”, D value: “0”) and eighteenth and twenty-fourth sum signal values (X value: “0”, Y value: “4”, Z value: “0”, D value: “0”) are most suitable for the separation. In both the twelfth and thirteenth sum values and the eighteenth and twenty-fourth sum values, the sum/difference signal value of the Y component signal is not 0, and the sum/difference signal value of the X component signal and the sum/difference signal value of the Z component signal are 0. Further, in both values, the sum/difference signal value of the oscillating component signal is 0. 
     As for the Z component signal, difference signal values (X value: “0”, Y value: “0”, Z value: “8”, D value: “0”) of fourth and seventeenth sum signal values (X value: “0”, Y value: “0”, Z value: “4”, D value: “0”) and ninth and twenty-first sum signal values (X value: “0”, Y value: “0”, Z value: “−4”, D value: “0”) are most suitable for the separation. In both the fourth and seventeenth values and the ninth and twenty-first values, the sum/difference signal value of the X component signal is 0 and the sum/difference signal value of the Z component signal is not 0. Further, in both values, the sum/difference signal value of the Y component signal is 0. Moreover, in both values, the sum/difference signal value of the oscillating component signal is 0. 
     It is to be noted that, when the Z component signal is calculated using difference signal values (X value: “0”, Y value: “0”, Z value: “8”, D value: “0”) of the thirteenth and eighteenth sum signal values (X value: “0”, Y value: “0”, Z value: “4”, D value: “0”) and the twelfth and twenty-fourth sum signal values (X value: “0”, Y value: “0”, Z value: “−4”, D value: “0”), the X component signal and the Y component signal can be calculated in a combination not using third sensing electrode sections  21   a ,  21   b . In other words, in TABLE 2, in combinations of tenth to fifteenth, eighteenth to twentieth, twenty-third, twenty-fourth, and twenty-seventh values, the X component signal, the Y component signal and the Z component signal can be calculated. 
     The angular velocity signals include the X component signal around the X axis, the Y component signal around the Y axis, the Z component signal around the Z axis and the oscillating component signal in the mutually orthogonal X axis, Y axis and Z axis, and the detection circuit section is provided with the separation circuit that is configured to perform signal separation in the above-mentioned suitable combinations so as to separate the X component signal, the Y component signal, the Z component signal and the oscillating component signal, whereby it is possible to detect an angular velocity around the plurality of detection axes in one detection element  1 . 
     Accordingly, in the case of detecting an angular velocity of a plurality of detection axes, a mounting area for mounting a plurality of detection elements  1  and a plurality of angular velocity sensors is not needed ensuring, but a mounting area for mounting only one detection element  1  may be ensured, and hence it is possible to seek reduction in size of a variety of electronic devices. 
     In particular, since the oscillating component signal can be separated, the oscillating component signal having a much larger output signal level than those of the X component signal, the Y component signal and the Z component signal is offset and separated, and hence it is possible to remove the oscillating component signal apt to become a noise component, so as to improve detection accuracy. 
     It should be noted that in one embodiment of the present invention, the configuration was described where in the condition that the angular velocity signals include the X component signal around the X axis, the Y component signal around the Y axis, the Z component signal around the Z axis and the oscillating component signal in the mutually orthogonal X axis, Y axis and Z axis, the detection circuit section is provided with the separation circuit that separates the X component signal, the Y component signal, the Z component signal and the oscillating component signal, but a configuration may be formed where the oscillating component signal is not included and a separation circuit is provided which simply separates the X component signal, the Y component signal and the Z component signal. 
     Further, a configuration may be formed where the angular velocity signals do not include the Y component signal but include the X component signal around the X axis, the Z component signal around the Z axis and the oscillating component signal in the mutually orthogonal X axis, Y axis and Z axis, and a separation circuit is formed which separates the X component signal, the Z component signal and the oscillating component signal, or a configuration may be formed where the angular velocity signals do not include the oscillating component signal, and a separation circuit that separates the X component signal and the Z component signal is provided. 
     Further, since respective signal polarities of signals outputted from lower electrodes  14  and upper electrodes  15  of first to third sensing electrode sections  19   a ,  19   b ,  20   a ,  20   b ,  21   a ,  21   b  are reversed, it is also possible to take advantage of the reversal signal polarity in addition or subtraction at the time of separation of the respective component signals (X component signal, Y component signal, Z component signal, oscillating component signal). 
     Moreover, although the method of calculating a sum signal after calculation of difference signals in the above embodiment was shown in the above embodiment, the order may be reverse thereto. In other words, taking the previous example as an example, after calculation of both the sum signal value of the fourth and ninth values and the sum signal value of the seventeenth and twenty-first values, the difference signal values thereof were calculated. However, the order may be reversed, and after calculation of the fourth and the seventeenth difference signals and the ninth and the twenty-first difference signals, the sum signal thereof may be calculated. 
     Furthermore, although the fourth value is the difference signal of  21   b  and  20   b  and the ninth value is the difference signal of  21   a  and  20   a  as the previous stages and the sum signal is calculated from the both values, the order may be revered, and after previous calculation of both a sum signal of  21   b  and  21   a  and a sum signal of  20   b  and  20   a , a difference signal of both values may be calculated. A variety of combinations can be considered in terms of the order of sum, difference, and sum. 
     In the above example, X, Y and Z may be replaced by one another. 
     INDUSTRIAL APPLICABILITY 
     The angular velocity sensor according to the present invention is not required to ensure a mounting area for mounting a plurality of detection elements and a plurality of angular velocity sensors, and is thus applicable to a variety of small-sized electronic devices.