JP2008145338A - Angular velocity sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an angular velocity sensor for improving detection precision of an angular velocity by receiving tension generated due to thermal stress from a substrate by a beam supporting a vibrator. <P>SOLUTION: A detection element 1 of the angular velocity sensor has first to fourth electrostatic force generating means 6-9, first and second vibrators 10, 11, an elastic connection beams 12 for elastically connecting the first and second vibrators 10, 11 and first to fourth electrostatic capacity detection means 13-16. Furthermore, the first to fourth support beams 17, 18, 19, 20 are easy to deform the first and second vibrators 10, 11 in an X axis direction respectively and support by being hardly deformed in Y axis and Z axis directions in a cantilever beam structure from one of the first and second vibrators 19, 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vibration type angular velocity sensor made of a semiconductor or the like.

  As a conventional vibration type angular velocity sensor made of a semiconductor or the like, a sensor having two vibrators supported symmetrically from both sides by a beam from a substrate is known (for example, see Patent Document 1). In this angular velocity sensor, these vibrators can be vibrated in mutually opposite phases in the X-axis direction horizontal to the substrate surface. The angular velocity is detected by detecting the displacement of the detection portion of the vibrator in the Y-axis direction that is horizontal to the substrate surface and perpendicular to the X-axis direction due to the Coriolis force generated by the application of the angular velocity from the outside.

JP 2002-188923 A

  Here, in the angular velocity sensor described in Patent Document 1, the two vibrators are supported symmetrically from both sides by beams from above the substrate. Therefore, the beam supporting the vibrator receives a tensile force generated by the thermal stress from the substrate. As a result, there is a problem that the resonance frequency of the vibrator changes and the angular velocity detection accuracy decreases.

  An object of the present invention is to provide an angular velocity sensor in which a beam supporting a vibrator receives a tensile force generated by thermal stress from a substrate and suppresses a change in the resonance frequency of the vibrator, and an angular velocity detection accuracy is improved. There is to do.

(1) In order to achieve the above object, the present invention provides a first and second vibrator elastically supported on a substrate and an elastic coupling beam for elastically coupling the first and second vibrators. Driving means for causing the first and second vibrators to vibrate in opposite phases to each other in the horizontal X-axis direction with respect to the substrate surface; and the substrate surface of the detection portion of the first and second vibrators, In a means for detecting a displacement in the Y-axis direction perpendicular to the X-axis direction and an angular velocity sensor for detecting an angular velocity based on the displacement in the Y-axis direction, a cantilever structure is formed from one of the first and second vibrators. The first and second vibrators are each provided with a support beam that supports the first vibrator and the second vibrator so as to be easily displaced in the X-axis direction and difficult to displace in the Y-axis and Z-axis directions.
With this configuration, the beam supporting the vibrator receives a tensile force generated by the thermal stress from the substrate, and the resonance frequency of the vibrator is prevented from changing, and the angular velocity detection accuracy can be improved.

  (2) In the above (1), preferably, the support beam supports the first and second vibrators at a plurality of locations.

  (3) In the above (2), preferably, the long sides of the support beams that support the first vibrator at a plurality of locations are arranged in parallel to each other, and the second vibrator is installed at a plurality of locations. The long sides of the supporting beams to be supported are arranged so as to be parallel to each other.

  (4) In the above (1), preferably, the support beam is arranged so as to support the first and second vibrators so as to be point-symmetrical from a central portion of the elastic coupling beam. .

  (5) In the above (1), preferably, the first and second vibrators are supported so as to vibrate in a pendulum shape within a plane constituted by the X axis and the Y axis.

  (6) In the above (1), preferably, the X-axis, the Y-axis, and the substrate rather than the support beam from the opposite side of the support beam of the first and second vibrators. An auxiliary beam that easily displaces in the Z-axis direction perpendicular to the surface and supports the first and second vibrators is provided.

  (7) In the above (1), preferably, in the Y-axis direction of the detection portion of the first and second vibrators caused by vibrating the first and second vibrators in the X-axis direction. And a detection circuit for distinguishing and detecting the vibration component in the Y-axis direction due to the angular velocity of the detection portions of the first and second driving bodies according to the frequency.

  (8) In the above (7), preferably, the detection circuit is configured to detect a detection portion of the first and second vibrators caused by vibrating the first and second vibrators in the X-axis direction. A first detection circuit that synchronously detects the vibration component in the Y-axis direction at twice the frequency that causes the first and second vibrators to vibrate in mutually opposite phases in the X-axis direction horizontal to the substrate surface; The vibration component in the Y-axis direction due to the angular velocity of the detection portion of the first and second vibrators causes the first and second vibrators to vibrate in mutually opposite phases in the X-axis direction horizontal to the substrate surface. It consists of a second detection circuit that performs synchronous detection at a frequency.

  (9) In the above (8), preferably, the means for detecting the displacement in the Y-axis direction of the detection portion of the first and second vibrators in the X-axis direction of the first and second vibrators. This displacement is detected.

  (10) In the above (8), preferably, the X-axis of the first and second vibrators detected by means for detecting displacement in the Y-axis direction of the detection portions of the first and second vibrators. Drive means for vibrating the first and second vibrators is provided so that the displacement in the direction becomes a predetermined value.

  (11) In the above (10), preferably, the driving means applies electrostatic force to the first and second vibrators, and causes the first and second vibrators to be in opposite phases to each other in the X-axis direction. Electrostatic force generating means for vibrating, and means for detecting displacement in the Y-axis direction of the detection portions of the first and second vibrators are provided in the Y-axis direction of the detection portions of the first and second drive bodies. Capacitance detection means for detecting displacement as a change in capacitance.

  According to the present invention, the beam supporting the vibrator receives a tensile force generated by the thermal stress from the substrate, and the resonance frequency of the vibrator is prevented from changing, and the angular velocity detection accuracy is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each embodiment of the present invention has the following four features.

  (1) The beam supporting the vibrator receives a tensile force generated by the thermal stress from the substrate, and the resonance frequency of the vibrator is prevented from changing, and the angular velocity detection accuracy can be improved.

  (2) Caused by vibrating the vibrator in the X-axis direction, that is, the vibration component in the Y-axis direction of the detection part of the vibrator generated by other than the angular velocity, and the Y-axis direction of the detection part of the vibrator due to the angular velocity The vibration component can be detected by being distinguished according to the frequency, and the angular velocity detection error can be reduced.

  (3) The means for detecting the displacement of the detection portion of the vibrator in the Y-axis direction can also detect the displacement of the vibrator in the X-axis direction, thereby reducing the number of electrodes and reducing the chip area.

  (4) The means for detecting the displacement in the Y-axis direction of the detection portion of the vibrator also detects the displacement of the vibrator in the X-axis direction so that the displacement of the vibrator in the X-axis direction becomes a predetermined value. The vibrator can be vibrated to improve the angular velocity detection accuracy.

Hereinafter, the configuration and operation of the angular velocity sensor according to the first embodiment of the present invention will be described with reference to FIGS.
First, the configuration of the angular velocity sensor according to the present embodiment will be described with reference to FIGS. 1 and 2.
FIG. 1 is a plan view showing a configuration of an angular velocity sensor according to the first embodiment of the present invention. 2 is a cross-sectional view taken along line AA ′ of FIG.

  As shown in FIG. 2, the detection element 1 includes a silicon layer 2, an insulating layer 3, a silicon substrate 4, and a glass substrate 5. Here, the silicon layer 2, the insulating layer 3, and the silicon substrate 4 constitute an SOI substrate. As will be described with reference to FIG. 1, a movable portion and a fixed portion are formed on the silicon layer 2 of the SOI substrate. The glass substrate 5 having the recesses is attached to the silicon layer 2 by anodic bonding or the like.

  1 and 2, the direction parallel to the surface of the silicon substrate 4 is the X axis, the direction horizontal to the surface of the silicon substrate 4 and the direction perpendicular to the X axis is the Y axis, and the direction perpendicular to the silicon substrate 4 is Z. Expressed as an axis.

  As shown in FIG. 1, the detection element 1 includes first to fourth electrostatic force generation means 6, 7, 8, 9, first and second vibrators 10, 11, an elastic connecting beam 12, To fourth capacitance detecting means 13, 14, 15, 16, first to fourth support beams 17, 18, 19, 20 and a frame portion 21.

  The elastic connection beam 12 elastically connects the first and second vibrators 10 and 11. The first to fourth support beams 17, 18, 19, 20 support the first and second vibrators 10, 11 that are easy to displace in the X-axis direction and difficult to displace in the Y-axis and Z-axis. The frame portion 21 is installed on the outer peripheral portion of each configuration described above, and is bonded to the glass substrate 5.

  Each configuration will be described below.

  The first electrostatic force generating means 6 includes a frame 6a, a comb-tooth electrode 6b, and a pad 6c. The frame 6a is fixed to the silicon substrate 4. The comb electrode 6b is configured by meshing a comb-shaped flat plate provided on each of the frame 6a and the first vibrator 10. The pad 6c is provided to take out an electrical connection from the frame 6a.

  The second electrostatic force generating means 7 is composed of a frame 7a, a comb electrode 7b, and a pad 7c. The frame 7a is fixed to the silicon substrate 4. The comb-tooth electrode 7b is configured by meshing a comb-shaped flat plate provided on the frame 7a and the first vibrator 10 respectively. The pad 7c is provided to take out an electrical connection from the frame 7a.

  The third electrostatic force generating means 8 includes a frame 8a, a comb electrode 8b, and a pad 8c. The frame 8a is fixed to the silicon substrate 4. The comb electrode 8b is configured by meshing a comb-shaped flat plate provided on each of the frame 8a and the second vibrator 11. The pad 8c is provided to take out an electrical connection from the frame 8a.

  The 4th electrostatic force generation means 9 is comprised from the flame | frame 9a, the comb-tooth electrode 9b, and the pad 9c. The frame 9a is fixed to the silicon substrate 4. The comb electrode 9b is configured by meshing a comb-like flat plate provided on each of the frame 9a and the second vibrator 11. The pad 9c is provided to take out an electrical connection from the frame 9a.

  Next, the first vibrator 10 includes a frame 10a, a detection portion 10b, and connecting beams 10c, 10d, 10e, and 10f. The frame 10a is arranged in a state of floating from the silicon substrate 4. The detection portion 10b is arranged inside the frame 10a so as to float from the silicon substrate 4. The connecting beams 10c, 10d, 10e, and 10f support the detection portion 10b with respect to the frame 10a in a state where the detection portion 10b is easily displaced in the Y-axis direction and difficult to be displaced in the X-axis and Z-axis directions. The connecting beams 10c, 10d, 10e, and 10f are arranged in a total of four on each side of the detection portion 10b so that the detection portion 10b is difficult to be displaced in the X-axis and Z-axis directions with respect to the frame 10a. ing.

  The second vibrator 11 includes a frame 11a, a detection portion 11b, and connecting beams 11c, 11d, 11e, and 11f. The frame 11a is arranged in a state of floating from the silicon substrate 4. The detection portion 11b is arranged inside the frame 11a so as to float from the silicon substrate 4. The connecting beams 11c, 11d, 11e, and 11f support the detection portion 11b with respect to the frame 11a in a state in which the detection portion 11b is easily displaced in the Y-axis direction and difficult to be displaced in the X-axis and Z-axis directions. The connecting beams 11c, 11d, 11e, and 11f are arranged in a total of four on each side of the detection portion 11b so that the detection portion 11b is difficult to be displaced in the X-axis and Z-axis directions with respect to the frame 11a. ing.

  Next, the elastic connecting beam 12 is composed of connecting beams 12a and 12b. The connecting beams 12a and 12b connect the frame 10a of the first vibrator 10 and the frame 11b of the second vibrator 11 so that they are easily displaced in the X-axis direction and difficult to be displaced in the Y-axis and Z-axis directions.

  Next, the first capacitance detecting means 13 is composed of a frame 13a, parallel plate electrodes 13b, and pads 13c. The frame 13a is fixed to the silicon substrate 4. The parallel plate electrodes 13b are configured by meshing comb-shaped plates respectively provided on the frame 13a and the detection portion 10b of the first vibrator 10. The pad 13c is used to take out an electrical connection from the frame 13a.

  The second capacitance detection means 14 includes a frame 14a, a parallel plate electrode 14b, and a pad 14c. The frame 14 a is fixed to the silicon substrate 4. The parallel plate electrode 14b is configured by meshing a comb-like plate provided respectively on the frame 14a and the detection portion 10b of the first vibrator 10. The pad 14c is used to take out an electrical connection from the frame 14a.

  The capacitances of the parallel plate electrodes 13b and 14b of the first and second capacitance detection means 13 and 14 are arranged so as to change in opposite phases when the detection portion 10b of the first vibrator 10 is displaced. Is done.

  The third electrostatic capacitance detection means 15 includes a frame 15a, a parallel plate electrode 15b, and a pad 15c. The frame 15 a is fixed to the silicon substrate 4. The parallel plate electrode 15b is configured by meshing a comb-like plate provided respectively on the frame 15a and the detection portion 10b of the second vibrator 11. The pad 15c is used to take out an electrical connection from the frame 15a.

  The fourth capacitance detection means 16 includes a frame 16a, a parallel plate electrode 16b, and a pad 16c. The frame 16 a is fixed to the silicon substrate 4. The parallel plate electrodes 16b are configured by meshing comb-shaped plates provided on the frame 16a and the detection portion 10b of the second vibrator 11 respectively. The pad 16c is used to take out an electrical connection from the frame 16a.

  The capacitances of the parallel plate electrodes 15b and 16b of the third and fourth capacitance detection means 15 and 16 are arranged so as to change in opposite phases when the detection portion 11b of the second vibrator 11 is displaced. Is done.

  Next, the first support beam 17 includes a support beam 17a, an anchor portion 17b, and a pad 17c. The support beam 17a supports the frame 10a of the first vibrator 10 so as to be easily displaced in the X-axis direction and not easily displaced in the Y-axis and Z-axis directions. The anchor portion 17 b fixes the support beam 17 a to the silicon substrate 4. The pad 17c is used to take out an electrical connection from the anchor portion 17b.

  The second support beam 18 includes a support beam 18a, an anchor portion 18b, and a pad 18c. The support beam 18a supports the frame 10a of the first vibrator 10 so as to be easily displaced in the X-axis direction and not easily displaced in the Y-axis and Z-axis directions. The anchor portion 18 b fixes the support beam 18 a to the silicon substrate 4. The pad 18c is used to take out an electrical connection from the anchor portion 18b.

  The first and second support beams 17 and 18 do not rotate on the plane composed of the X axis and the Y axis and the plane composed of the X axis and the Z axis of the frame 10a of the first vibrator 10. Two in total, one at each end of one side of the quadrangular frame 10 a of the first vibrator 10.

  In addition, the first and second support beams 17 and 18 are first to first frames 10a of the first vibrator 10 so that the frame 10a of the first vibrator 10 does not rotate in a plane constituted by the X axis and the Y axis. The long sides of the second support beams 17 and 18 are arranged in parallel to each other.

  The third support beam 19 includes a support beam 19a, an anchor portion 19b, and a pad 19c. The support beam 19a supports the frame 10a of the first vibrator 10 that is easily displaced in the X-axis direction and is difficult to be displaced in the Y-axis and Z-axis directions. The anchor part 19 b fixes the support beam 19 a to the silicon substrate 4. The pad 19c is used to take out an electrical connection from the anchor portion 19b.

  The fourth support beam 20 includes a support beam 20a, an anchor portion 20b, and a pad 20c. The support beam 20a supports the frame 10a of the first vibrator 10 so as to be easily displaced in the X-axis direction and not easily displaced in the Y-axis and Z-axis directions. The anchor part 20 b fixes the support beam 20 a to the silicon substrate 4. The pad 20c is used to take out an electrical connection from the anchor portion 20b.

  Note that the third and fourth support beams 19 and 20 do not rotate on the plane composed of the X axis and the Y axis and the plane composed of the X axis and the Z axis of the frame 11a of the second vibrator 11. Two in total, one at each end of the frame 11 a of the second vibrator 11.

  Further, the third and fourth support beams 19 and 20 are third to third frames from the frame 11a of the second vibrator 11 so that the frame 11a of the second vibrator 11 does not rotate in a plane constituted by the X axis and the Y axis. The fourth support beams 19 and 20 are arranged so that the long sides thereof are parallel to each other.

  In addition, as shown in FIG. 2, the pads 7 c, 8 c, 13 c, 14 c, 15 c, and 16 c allow electric wiring to be drawn out of the glass substrate 5 through through holes formed in the glass substrate 5. Thus, by taking out the electrical connection of the pads 7c, 8c, 13c, 14c, 15c, 16c through the glass substrate 5, the frames 10a, 11a of the first and second vibrators 10, 11 and the connecting beams 10c, .., 10f, 11c,..., 11f and the elastic connecting beam 12 need not be provided with notches as lead portions for wiring, and an unnecessary vibration mode can be obtained by increasing the rigidity of the first and second vibrators 10 and 11. Can be reduced.

Next, the 1st characteristic of the angular velocity sensor which is this embodiment is demonstrated using FIGS. 1-3.
FIG. 3A is a diagram schematically showing a cross-sectional view of BB ′ of the detection element 1 of the angular velocity sensor according to the first embodiment of the present invention. FIG. 3B is a cross-sectional view of a detection element of an angular velocity sensor in which a conventional vibrator 23 disclosed in Japanese Patent Application Laid-Open No. 2002-188923 and the like is supported symmetrically from both sides by beams 22 and 24 from the substrate. FIG.

  (1) The support beams 17 and 18 and the support beams 19 and 20 that respectively support the first and second vibrators 10 and 11 receive a tensile force generated by thermal stress from the silicon substrate 4, and thereby A change in the resonance frequency of the vibrators 10 and 11 is suppressed, and the angular velocity detection accuracy is improved.

  An angular velocity sensor in an automobile is used from a cold region to a desert region, and receives radiant heat from an engine. Therefore, in order to use the angular velocity sensor of this embodiment for an automobile, a wide range of −40 ° C. to + 130 ° C. It is necessary to operate normally in the temperature range.

  When the angular velocity sensor of this embodiment is used at a high temperature or a low temperature, it is shown in FIG. 3 from the difference in thermal expansion coefficient between the frame that supports the detection element 1 from the outside and the silicon substrate 4 that is not shown in FIGS. As described above, warpage occurs in the silicon substrate 4.

  As shown in FIG. 3B, in the conventional angular velocity sensor, the vibrator 10 is supported symmetrically from both sides by beams 17 and 22 from above the substrate. Here, when the silicon substrate 4 is warped, a tensile force generated by thermal stress from the silicon substrate 4 is applied to the beams 17 and 22 that support the vibrator 10 symmetrically from both sides. As a result, the spring constants of the beams 17 and 22 that support the vibrator 10 symmetrically from both sides change, the resonance frequency of the vibrator 10 in the X-axis direction changes, and the angular velocity detection accuracy decreases.

  On the other hand, as shown in FIG. 3A, the angular velocity sensor according to the present embodiment has a cantilever structure in which the first and second vibrators 10 and 11 are supported by support beams 17, 18, 19, and 20 from the substrate. It is supported by. Here, when the silicon substrate 4 is warped, the support beams 17, 18, 19, and 20 that support the first and second vibrators 10 and 11 in a cantilever structure from one side are heated by the heat from the silicon substrate 4. The tensile force generated by the stress is not applied. Accordingly, the spring constants of the support beams 17, 18, 19, and 20 that support the first and second vibrators 10 and 11 from one side in a cantilever structure do not change, and the X of the first and second vibrators 10 and 11 does not change. Since the resonance frequency in the plane composed of the axis and the Y-axis does not change, the angular velocity detection accuracy can be improved.

Next, a second feature of the angular velocity sensor according to the present embodiment will be described with reference to FIGS. 4 and 5.
FIG. 4A is a diagram schematically illustrating the vibration directions of the first and second vibrators 10 and 11 of the angular velocity sensor according to the first embodiment of the present invention. FIG. 4B schematically shows the vibration direction of a vibrator of an angular velocity sensor in which a conventional vibrator disclosed in Japanese Patent Application Laid-Open No. 2002-188923 is supported symmetrically from both sides by a beam or the like from the substrate. FIG. FIG. 5 is a drive circuit of the angular velocity sensor according to the first embodiment of the present invention.

  (2) Due to vibrating the first and second vibrators 10 and 11 in the X-axis direction, that is, in the Y-axis direction of the detection portions 10b and 11b of the first and second vibrators generated by other than the angular velocity. And the vibration component in the Y-axis direction of the detection portions 102 and 112 of the first and second vibrators 10 and 11 due to the angular velocity can be distinguished and detected by the frequency, and the angular velocity detection error can be reduced. Can do.

  As shown in FIG. 4B, in the conventional angular velocity sensor, the vibrator is supported symmetrically from both sides by a beam or the like from above the substrate. That is, the first and second vibrators 10 and 11 are supported symmetrically from both sides by the support beams 17, 18, 19, 20, 22, 23, 24, and 25 from the substrate. On the other hand, in the driving means that vibrates the first and second vibrators 10 and 11 in opposite phases to each other in the X-axis direction, the vibration varies, and the support beams 17, 18, 19, 20 and 22, 23, There are 24 and 25 processing variations. Therefore, when the first and second vibrators 10 and 11 are vibrated in the X-axis direction by the driving means that vibrates the X-axis direction in opposite phases to each other, the first and second vibrators 10 and 11 are shown in FIG. As shown in (B), it vibrates linearly or elliptically on a plane composed of the X axis and the Y axis.

  At this time, assuming that the frequency of the vibration component in the X-axis direction of the linear or elliptical vibration of the detection portions of the first and second vibrators 10 and 11 is f1, the detection portions of the first and second vibrators 10 and 11 are detected. The frequency of the vibration component in the Y-axis direction of the linear or elliptical vibration is f1. The frequency of the vibration component in the Y-axis direction due to the angular velocity of the detection portions of the first and second vibrators 10 and 11 is f1.

  Therefore, the first and second vibrators 10 and 11 are caused to vibrate in the X-axis direction, that is, the detection portions of the first and second vibrators 10 and 11 that are generated by other than the angular velocity in the Y-axis direction. The vibration component in the Y-axis direction of the detection part of the first and second vibrators 10 and 11 based on the vibration component and the angular velocity cannot be distinguished, resulting in an angular velocity detection error.

  On the other hand, as shown in FIG. 4A, in the angular velocity sensor of the present embodiment, the first and second vibrators 10 and 11 are cantilevered from one side by support beams 17, 18, 19 and 20 from above the substrate. It is supported by. When the first and second vibrators 10 and 11 are vibrated by the first and second electrostatic force generation means 6 and 7 and the third and fourth electrostatic force generation means 8 and 9, respectively, the first and second vibrators 10 and 11 are supported in a cantilever structure from one side by support beams 17, 18, 19, and 20 from above the substrate, and therefore the first and second vibrators 10 and 11 are shown in FIG. As described above, it vibrates like a pendulum in a plane composed of the X axis and the Y axis.

  At this time, if the frequency of the vibration component in the X-axis direction of the pendulum vibration of the detection portions 10b and 11b of the first and second vibrators 10 and 11 is f1, the detection portions of the first and second vibrators 10 and 11 are detected. The frequency of the vibration component in the Y-axis direction of the pendulum vibrations 10b and 11b is 2 × f1. Further, the frequency of the vibration component in the Y-axis direction due to the angular velocity of the detection portions 10b and 11b of the first and second vibrators 10 and 11 is f1.

  Therefore, the Y-axis of the detection portions 10b and 11b of the first and second vibrators 10 and 11 caused by vibrating the first and second vibrators 10 and 11 in the X-axis direction, that is, generated by other than the angular velocity. The vibration component in the Y-axis direction of the detection portions 10b and 11b of the first and second vibrators 10 and 11 due to the vibration component in the direction and the angular velocity can be distinguished by the frequency, and the detection error of the angular velocity can be reduced. it can.

Next, the configuration of the drive circuit for the angular velocity sensor according to the present embodiment will be described with reference to FIG.
FIG. 5 is a circuit diagram of the drive circuit for the angular velocity sensor according to the first embodiment of the present invention. In FIG. 5, the first to fourth electrostatic force generation means 6, 7, 8, 9 and the first to fourth electrostatic capacity detection means 13, 14, 15, 16 of the detection element 1 are electrically connected to the capacitor for convenience. It is written as a symbol.

  The oscillator 31a generates an oscillation waveform having a frequency f2, and applies a voltage to the first and fourth capacitance detection means 13 and 16. The inverter 31b inverts the signal of the oscillator 31a and applies a voltage to the second and third capacitance detection means 14 and 15. The C / V converter 32 is a common terminal of a capacitor constituted by the first to fourth electrostatic force generation means 6, 7, 8, 9 and the first to fourth capacitance detection means 13, 14, 15, 16. Is generated by applying a voltage to the first to fourth electrostatic force generation means 6, 7, 8, 9 and the first to fourth electrostatic capacity detection means 13, 14, 15, 16. Convert charge to voltage. The multiplier 33a multiplies the output of the C / V converter 32 by the signal having the frequency f2. The LPF 33b removes high frequency components from the output of the multiplier 33a.

  The multiplier 34a multiplies the output of the LPF 33b and the signal of the frequency f1. The LPF 34b removes the high frequency component of the output of the multiplier 34a. The multiplier 35a multiplies the output of the LPF 33b by a signal having a frequency of 2 × f1. The LPF 35b removes the high frequency component of the output of the multiplier 35a.

  The adder / subtractor 37a subtracts a predetermined reference voltage VR from the output of the LPF 35b. The amplifier 37b amplifies the output of the adder / subtractor 37a and outputs a signal corresponding to the displacement of the first and second vibrators 10 and 11 in the X-axis direction. Multiplier 37c multiplies the output of amplifier 37b by the signal of frequency f1. The adder 37d adds the bias voltage VB to the output of the multiplier 37c and applies a voltage to the first and fourth electrostatic force generating means 6 and 9. The inverter 37e inverts the output of the multiplier 37c. The adder 37f adds the bias voltage VB to the output of the inverter 37e and applies the voltage to the second and third electrostatic force generation means 7,8.

  The oscillator 38a generates an oscillation waveform having a frequency of 2 × f1, and applies a voltage to the multiplier 35a. The frequency divider 38b divides the output of the oscillator 38a by 1/2, generates an oscillation waveform of the frequency f1, and applies a voltage to the multipliers 34a and 37c. The reference power supply 39a generates a reference voltage VR and applies it to the adder / subtractor 37a. The bias power supply 39b generates a bias voltage VB and applies it to the adders 37d and 37f.

  Hereinafter, the operation of the drive circuit will be described. And the 3rd and 4th characteristic of the angular velocity sensor which is the 1st Embodiment of this invention is demonstrated.

  (3) First and second capacitance detection means 13 and 14 for detecting displacement in the Y-axis direction of the detection portions 102 and 112 of the first and second vibrators 10 and 11, and third and fourth capacitances. The detecting means 15 and 16 can detect the displacement of the first and second vibrators 10 and 11 in the X-axis direction to reduce the chip area.

  (4) First and second capacitance detecting means 13 and 14 for detecting displacement in the Y-axis direction of the detection portions 102 and 112 of the first and second vibrators 10 and 11, and third and fourth capacitances. The detection means 15 and 16 also detect the displacement of the first and second vibrators 10 and 11 in the X-axis direction, and the displacement of the first and second vibrators 10 and 11 in the X-axis direction is a predetermined value. The first and second vibrators 10 and 11 can be vibrated so that the angular velocity detection accuracy can be improved.

  First, the Y-axis of the detection portions 10b and 11b of the first and second vibrators 10 and 11 caused by vibrating the first and second vibrators 10 and 11 in the X-axis direction, that is, generated by other than the angular velocity. The operation of detecting the vibration component in the direction, that is, the third feature will be described.

  The detection of the vibration component in the Y-axis direction of the detection portions 10b and 11b of the first and second vibrators 10 and 11 generated by other than the angular velocity is performed by the electrostatic capacitances of the first and fourth capacitance detection means 13 and 16. This is realized by detecting a difference signal between the capacitances of the second and third capacitance detection means 14 and 15 and detecting a 2 × f1 component of the difference signal.

  In this drive circuit, in order to detect a difference signal between the capacitances of the first and fourth capacitance detection means 13 and 16 and the capacitances of the second and third capacitance detection means 14 and 15, The first and fourth capacitance detection means 13, 16 and the second and third capacitance detection means 14, 15 are applied with inverted signals of the frequency f 2, respectively. , 16 and the charge depending on the difference between the second and third capacitance detecting means 14 and 15 are passed to the C / V converter 32.

  At this time, the frequency f2 is set to a frequency sufficiently higher than the frequency f1, and the frequency region where the gain of the C / V converter 32 is high is used.

  In this way, the output of the C / V converter 32 has a frequency component of the frequency f2, and the capacitances of the first and fourth capacitance detection means 13, 16 and the second and third capacitance detection means. A voltage waveform depending on the difference in capacitance between 14 and 15 appears.

  By multiplying this voltage waveform by the signal of frequency f2 by the multiplier 33a and removing the high frequency component by the LPF 33b, the signal component of the frequency f2 of the output voltage of the C / V converter 32 is extracted. A difference signal between the capacitance of the fourth capacitance detection means 13 and 16 and the capacitance of the second and third capacitance detection means 14 and 15 is detected.

  The detection signal is multiplied by the signal of frequency 2 × f1 by the multiplier 35a and the high frequency component is removed by the LPF 35b, thereby extracting the signal component of the frequency 2 × f1 of the detection signal and generating by other than the angular velocity. A signal corresponding to the vibration component in the Y-axis direction of the detection portions 10b and 11b of the first and second vibrators 10 and 11 is obtained.

  As described above, the first and second capacitance detection units 13 and 14 and the third and fourth capacitance detection units 15 and 16 that detect the displacement in the Y-axis direction, which are the third feature, The displacement in the X-axis direction of the second vibrators 10 and 11 can also be detected. In the conventional angular velocity sensor, for example, in Japanese Patent Laid-Open No. 2002-188923, the displacement in the X-axis direction is detected by a dedicated sensor for detecting the displacement in the X-axis direction, which is the monitor electrode 52 shown in FIG. . On the other hand, in this embodiment, a dedicated sensor unit for detecting displacement in the X-axis direction is not required, and the chip area can be reduced.

  Next, the detection operation of the displacement in the X-axis direction of the first and second vibrators 10 and 11 will be described.

  Detection of the displacement of the first and second vibrators 10 and 11 in the X-axis direction can also be performed by the first and second electrostatic force generation means 6 and 7 and the third and fourth electrostatic force generation means 8 and 9. However, the first and second electrostatic force generating means 6 and 7 and the third and fourth electrostatic force generating means 8 and 9 have a large electrostatic capacity to generate a large electrostatic force, and the first and second electrostatic force generating means. When a voltage is applied to the means 6 and 7 and the third and fourth electrostatic force generation means 8 and 9, the C / V converter 32 may be saturated.

  In order to detect the displacement of the first and second vibrators 10 and 11 in the X-axis direction, the first and second capacitance detection means 13 and 14 and the third and fourth capacitance detection means 15 and In addition to 16, electrostatic capacity detection means for detecting the displacement of the first and second vibrators 10 and 11 in the X-axis direction can be provided on the frames 10 a and 11 a of the first and second vibrators 10 and 11. However, it is necessary to increase the chip area.

  Therefore, in the angular velocity sensor of the present embodiment, the displacement of the first and second vibrators 10 and 11 in the X-axis direction is detected by the first and second capacitance detection means 13 and 14 and the third and fourth capacitance detection. A method of detecting by means 15 and 16 is employed.

  The first and second vibrators 10 and 11 are displaced in the X-axis direction because the first and second vibrators 10 and 11 vibrate in a pendulum shape on a plane constituted by the X-axis and the Y-axis. Due to the vibration of the second vibrators 10 and 11 in the X-axis direction, that is, due to the displacement of the detection portions 10b and 11b of the first and second vibrators 10 and 11 in the Y-axis direction caused by other than the angular velocity. Dependent.

  Therefore, the first and second vibrators 10 and 11 are caused to vibrate in the X-axis direction, and the first and second vibrators 10 and 11 are detected from the displacement of the detection portions 10b and 11b in the Y-axis direction. The displacement in the X-axis direction of the second vibrators 10 and 11 can be detected.

  Next, a description will be given of a driving force servo operation for vibrating the first and second vibrators 10 and 11 so that the displacements in the X-axis direction of the first and second vibrators 10 and 11 become predetermined values.

  In the drive circuit of the present embodiment, the difference signal between the capacitances of the first and fourth capacitance detection units 13 and 16 and the capacitances of the second and third capacitance detection units 14 and 15 is constant. As shown, the vibration components in the Y-axis direction of the detection portions 10b and 11b of the first and second vibrators 10 and 11 caused by vibrating the first and second vibrators 10 and 11 in the X-axis direction are obtained. In this method, a method of applying a voltage to the first and second electrostatic force generating means 6 and 7 and the third and fourth electrostatic force generating means 8 and 9 is adopted.

  In the drive circuit of the present embodiment, the output of the LPF 35b includes the detection portions 10b, 10b of the first and second vibrators 10, 11 caused by vibrating the first and second vibrators 10, 11 in the X-axis direction. A voltage depending on the displacement of 11b in the Y-axis direction is detected.

  Then, a predetermined reference voltage VR is subtracted from the detected voltage by the adder / subtractor 37a. The reference voltage VR is a reference voltage that takes a displacement in the X-axis direction of the first and second vibrators 10 and 11 as a predetermined value. The first and second vibrators 10 and 11 are servo-operated so that the displacement in the X-axis direction becomes the reference voltage VR.

  The output of the adder / subtractor 37a is amplified by the amplifier 37b, and the output of the amplifier 37b is multiplied by the signal of the frequency f1 by the multiplier 37c. A bias voltage VB is added to the output of the multiplier 37c by an adder 37d and applied to the first and fourth electrostatic force generating means 6 and 9, thereby providing static electricity to the first and fourth electrostatic force generating means 6 and 9. A force is generated to pull the first and second vibrators 10 and 11 from both sides at the frequency f1.

  Further, the output of the multiplier 37c is inverted by the inverter 37e, and a signal obtained by adding the bias voltage VB by the adder 37f is applied to the output of the inverter 37e. . As a result, the second and third electrostatic force generating means 7 and 8 generate an electrostatic force to pull the first and second vibrators 10 and 11 from both sides at the frequency f1.

  At this time, the frequency f1 is adjusted to the resonance frequency of the antiphase vibration of the first and second vibrators 10 and 11, so that the first and second vibrators 10 and 11 vibrate greatly in antiphase.

  In this way, the first and fourth electrostatic force generating means 6 and 9 and the second and third electrostatic force generating means 7 and 8 can apply the electrostatic force to the first and second vibrators 10 and 11, thereby The difference between the capacitance of the fourth capacitance detection means 13 and 16 and the capacitance of the second and third capacitance detection means 14 and 15 is made constant.

  That is, the displacement in the Y-axis direction of the detection portions 10b and 11b of the first and second vibrators 10 and 11 caused by vibrating the first and second vibrators 10 and 11 in the X-axis direction is kept constant. The amplitude of vibration in the X-axis direction of the first and second vibrators 10 and 11 can be kept constant.

  As a result, even when external vibration is applied to the angular velocity sensor, the first and second vibrators are arranged such that the displacements of the first and second vibrators 10 and 11 in the X-axis direction have predetermined values. 10 and 11 can be vibrated to improve the angular velocity detection accuracy as in the fourth feature.

  Next, the angular velocity detection operation will be described.

  The angular velocity is detected by detecting a difference signal between the capacitances of the first and fourth capacitance detection means 13 and 16 and the capacitances of the second and third capacitance detection means 14 and 15 and calculating the difference. This can be realized by detecting the component of the frequency f1 of the signal.

  In the drive circuit of this embodiment, in order to detect a difference signal between the capacitances of the first and fourth capacitance detection units 13 and 16 and the capacitances of the second and third capacitance detection units 14 and 15. The first and fourth capacitances are applied to the first and fourth capacitance detection means 13 and 16 and the second and third capacitance detection means 14 and 15 by applying inverted signals of the frequency f2, respectively. A charge depending on the difference between the capacitance of the detection means 13, 16 and the capacitance of the second and third capacitance detection means 14, 15 is supplied to the C / V converter 32.

  At this time, the frequency f2 is set to a frequency sufficiently higher than the frequency f1, and the frequency region where the gain of the C / V converter 32 is high is used.

  In this way, the output of the C / V converter 32 has a frequency component of the frequency f2, and the capacitances of the first and fourth capacitance detection means 13, 16 and the second and third capacitance detection means. A voltage waveform depending on the difference between the capacitances 14 and 15 appears.

  This voltage waveform is multiplied by the signal of frequency f2 by multiplier 33a, the high frequency component is removed by LPF 33b, and the signal component of frequency f2 of the output voltage of C / V converter 32 is extracted. A difference signal between the capacitances of the capacitance detection units 13 and 16 and the capacitances of the second and third capacitance detection units 14 and 15 is detected.

  Then, the detection signal is multiplied by the signal of the frequency f1 by the multiplier 34a and the high frequency component is removed by the LPF 34b, thereby extracting the signal component of the frequency f1 of the detection signal and obtaining a signal corresponding to the angular velocity. Can do.

  As described above, according to the present embodiment, (1) the beam supporting the vibrator receives a tensile force generated by the thermal stress from the substrate, and the resonance frequency of the vibrator is prevented from changing. The detection accuracy of angular velocity can be improved.

  (2) In addition, the vibration component in the Y-axis direction of the detection part of the vibrator that is caused by vibrating the vibrator in the X-axis direction, that is, other than the angular velocity, and the Y of the detection part of the vibrator due to the angular velocity. The vibration component in the axial direction can be detected by being distinguished by the frequency, and the angular velocity detection error can be reduced.

  (3) Further, the means for detecting the displacement of the detection portion of the vibrator in the Y-axis direction can also detect the displacement of the vibrator in the X-axis direction, thereby reducing the number of electrodes and reducing the chip area.

  (4) Further, the means for detecting the displacement of the detection portion of the vibrator in the Y-axis direction also detects the displacement of the vibrator in the X-axis direction, and the displacement of the vibrator in the X-axis direction is set to a predetermined value. Thus, the vibrator can be vibrated to improve the angular velocity detection accuracy.

Next, the configuration of the angular velocity sensor according to the second embodiment of the present invention will be described with reference to FIG.
FIG. 6 is a plan view of the detection element of the angular velocity sensor according to the second embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts. 6 is the same as that shown in FIG. Further, the configuration of the drive circuit is the same as that shown in FIG.

  In this embodiment, the detection unit 1A of the angular velocity sensor is a means for supporting the first and second vibrators 10 and 11 of the detection unit 1 of the angular velocity sensor from the substrate in the first embodiment shown in FIG. The configuration has been changed.

  Means for supporting the first and second vibrators 10 and 11 of the detection unit 1A of the angular velocity sensor according to the present embodiment from the substrate are the same as the first to fourth support beams 17, 18, 19, and 20 similar to FIG. In addition, the first and second auxiliary beams 41 and 42 are provided. The first to fourth support beams 17, 18, 19, 20 support the first and second vibrators 10, 11 that are easy to displace in the X-axis direction and difficult to displace in the Y-axis and Z-axis directions. The first and second auxiliary beams 41 and 42 support the first and second vibrators 10 and 11 so as to be easily displaced in the X-axis, Y-axis, and Z-axis directions. Here, the spring constants in the X-axis, Y-axis, and Z-axis directions of the first and second auxiliary beams 41 and 42 are the X-axis, Y-axis, and Z-axis of the first to fourth support beams 17, 18, 19, and 20, respectively. It is set smaller than the spring constant in the direction.

  Each configuration will be described below.

  The first auxiliary beam 41 includes a support beam 41a, a support beam 41b, and anchor portions 41c and 41d. The support beam 41a supports the frame 10a of the first vibrator 10 so as to be easily displaced in the X-axis and Z-axis directions. The support beam 41b is connected to the support beam 41a symmetrically in the X-axis direction, and supports the frame 10a of the first vibrator 10 so as to be easily displaced in the Y-axis and Z-axis directions. The anchor portions 41c and 41d fix the support beam 41b to the silicon substrate 4 from both sides.

  The second auxiliary beam 42 includes a support beam 42a, a support beam 42b, and anchor portions 42c and 42d. The support beam 42a supports the frame 10a of the second vibrator 11 so as to be easily displaced in the X-axis and Z-axis directions. The support beam 42b is connected symmetrically from the support beam 42a in the X-axis direction, and supports the frame 11a of the second vibrator 11 so as to be easily displaced in the Y-axis and Z-axis directions. The anchor portions 42c and 42d fix the support beam 42b to the silicon substrate 4 from both sides.

  Since the first and second vibrators 10 and 11 are supported by the first to fourth support beams 17, 18, 19 and 20 and the first and second auxiliary beams 41 and 42 from above the substrate, The rigidity of the first and second vibrators 10 and 11 in the Z-axis direction is increased.

  Next, when this angular velocity sensor is used at a high temperature or a low temperature, warpage occurs in the silicon substrate 4 due to a difference in thermal expansion coefficient between the frame supporting the detection element 1 and the silicon substrate 4 from outside, which is not shown in FIG. A tensile force generated by thermal stress from the silicon substrate 4 is applied to the first to fourth support beams 17 to 20 and the first and second auxiliary beams 41 and 42.

  Here, the spring constants in the X-axis, Y-axis, and Z-axis directions of the first and second auxiliary beams 41 and 42 are the X-axis, Y-axis, and Z-axis of the first to fourth support beams 17, 18, 19, and 20, respectively. Since the spring constant in the direction is set to be smaller, the tensile force generated by the thermal stress from the silicon substrate 4 is the first and second auxiliary than the first to fourth support beams 17, 18, 19, 20. Largely added to the beams 41 and 42. Therefore, although the spring constants of the first and second auxiliary beams 41 and 42 change, the spring constants of the first to fourth support beams 17, 18, 19 and 20 do not change.

  In addition, the resonance frequency on the plane composed of the X axis and the Y axis of the first and second vibrators 10 and 11 is the mass of the first and second vibrators 10 and 11 and the first to fourth supports, respectively. It is determined by the spring constant of the beams 17, 18, 19, 20. Even when a tensile force is generated due to thermal stress from the silicon substrate 4, the spring constants of the first to fourth support beams 17, 18, 19, and 20 do not change, and therefore the X of the first and second vibrators 10 and 11 does not change. Since the resonance frequency in the plane composed of the axis and the Y-axis does not change, the angular velocity detection accuracy can be improved.

  Next, when the first and second vibrators 10 and 11 are vibrated by the first and second electrostatic force generation means 6 and 7 and the third and fourth electrostatic force generation means 8 and 9, respectively, The first auxiliary beam 41 is more easily displaced in the X-axis and Y-axis directions than the second support beams 17 and 18, and the second auxiliary beam 42 is more X-axis than the third and fourth support beams 19 and 20. Since the first and second vibrators 10 and 11 are easily displaced in the Y-axis direction, the first and second vibrators 10 and 11 vibrate in a pendulum shape on a plane constituted by the X-axis and the Y-axis, respectively.

  At this time, if the frequency of the vibration component in the X-axis direction of the pendulum vibration of the detection portions 10b and 11b of the first and second vibrators 10 and 11 is f1, the detection portions of the first and second vibrators 10 and 11 are detected. The frequency of the vibration component in the Y-axis direction of the pendulum vibrations 10b and 11b is 2 × f1.

  The frequency of the vibration component in the Y-axis direction due to the angular velocity of the detection portions 10b and 11b of the first and second vibrators 10 and 11 is f1.

  Therefore, the Y-axis of the detection portions 10b and 11b of the first and second vibrators 10 and 11 caused by vibrating the first and second vibrators 10 and 11 in the X-axis direction, that is, generated by other than the angular velocity. The vibration component in the Y-axis direction of the detection portions 10b and 11b of the first and second vibrators 10 and 11 due to the vibration component in the direction and the angular velocity can be distinguished by the frequency, and the detection error of the angular velocity can be reduced. it can.

  As described above, according to the present embodiment, (1) the beam supporting the vibrator receives a tensile force generated by the thermal stress from the substrate, and the resonance frequency of the vibrator is prevented from changing. The detection accuracy of angular velocity can be improved.

  (2) In addition, the vibration component in the Y-axis direction of the detection part of the vibrator that is caused by vibrating the vibrator in the X-axis direction, that is, other than the angular velocity, and the Y of the detection part of the vibrator due to the angular velocity. The vibration component in the axial direction can be detected by being distinguished by the frequency, and the angular velocity detection error can be reduced.

  (3) Further, the means for detecting the displacement of the detection portion of the vibrator in the Y-axis direction can also detect the displacement of the vibrator in the X-axis direction, thereby reducing the number of electrodes and reducing the chip area.

  (4) Further, the means for detecting the displacement of the detection portion of the vibrator in the Y-axis direction also detects the displacement of the vibrator in the X-axis direction, and the displacement of the vibrator in the X-axis direction is set to a predetermined value. Thus, the vibrator can be vibrated to improve the angular velocity detection accuracy.

  (5) Furthermore, the rigidity in the Z-axis direction of the first and second vibrators 10 and 11 can be increased.

Next, the configuration of the angular velocity sensor according to the third embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a plan view of the detection element of the angular velocity sensor according to the third embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts. 7 is the same as that shown in FIG. Further, the configuration of the drive circuit is the same as that shown in FIG.

  In the present embodiment, the detection unit 1B of the angular velocity sensor has changed the configuration of the means for supporting the first and second vibrators 10 and 11 of the detection unit 1 of the angular velocity sensor of the embodiment shown in FIG. 1 from the substrate. Is.

  The means for supporting the first and second vibrators 10 and 11 of the detection unit 1 of the angular velocity sensor according to the third embodiment from the substrate is constituted by the first to fourth support beams 17, 18, 19 ′, and 20 ′. Is done. The first to fourth support beams 17, 18, 19 ′, 20 ′ support the first and second vibrators 10, 11 that are easy to displace in the X-axis direction and difficult to displace in the Y-axis and Z-axis directions, respectively. To do. Here, the first and second support beams 17 and 18 and the third and fourth support beams 19 ′ and 20 ′ are arranged so as to be point-symmetric with respect to each other from the center of the elastic connection beam 12.

  As described above, the first and second support beams 17 and 18 and the third and fourth support beams 19 ′ and 20 ′ that support the first and second vibrators 10 and 11, respectively, are the center of the elastic coupling beam 12. It is arranged so as to be point-symmetric from the part. Therefore, when the first and second vibrators 10 and 11 are vibrated by the first and second electrostatic force generation means 6 and 7 and the third and fourth electrostatic force generation means 8 and 9, respectively, The two vibrators 10 and 11 vibrate in a pendulum shape symmetrically with respect to each other from the center of the elastic connecting beam 12 on a plane constituted by the X axis and the Y axis.

  Accordingly, the sum of the momentum and energy of the first and second vibrators 10 and 11 is 0, and the momentum and energy leaking from the detection element 1 through the silicon substrate 4 and the frame supporting the detection element 1 from the outside not shown in FIG. Becomes 0, and the vibrations of the first and second vibrators 10 and 11 can be prevented from leaking outside. As a result, the first and second vibrators 10 and 11 can be stably vibrated in a pendulum shape on the plane constituted by the X-axis and the Y-axis, so that the angular velocity detection accuracy can be improved.

  As described above, according to the present embodiment, (1) the beam supporting the vibrator receives a tensile force generated by the thermal stress from the substrate, and the resonance frequency of the vibrator is prevented from changing. The detection accuracy of angular velocity can be improved.

  (2) In addition, the vibration component in the Y-axis direction of the detection part of the vibrator that is caused by vibrating the vibrator in the X-axis direction, that is, other than the angular velocity, and the Y of the detection part of the vibrator due to the angular velocity. The vibration component in the axial direction can be detected by being distinguished by the frequency, and the angular velocity detection error can be reduced.

  (3) Further, the means for detecting the displacement of the detection portion of the vibrator in the Y-axis direction can also detect the displacement of the vibrator in the X-axis direction, thereby reducing the number of electrodes and reducing the chip area.

  (4) Further, the means for detecting the displacement of the detection portion of the vibrator in the Y-axis direction also detects the displacement of the vibrator in the X-axis direction, and the displacement of the vibrator in the X-axis direction is set to a predetermined value. Thus, the vibrator can be vibrated to improve the angular velocity detection accuracy.

  (5) Furthermore, it is possible to prevent the vibrations of the first and second vibrators 10 and 11 from leaking to the outside.

Next, the configuration of the angular velocity sensor according to the fourth embodiment of the present invention will be described with reference to FIG.
FIG. 8 is a plan view of a detection element of the angular velocity sensor according to the fourth embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts. 8 is the same as that shown in FIG. Further, the configuration of the drive circuit is the same as that shown in FIG.

  In this embodiment, the detection unit 1C of the angular velocity sensor has changed the configuration of the means for supporting the first and second vibrators 10 and 11 of the detection unit 1 of the angular velocity sensor of the embodiment shown in FIG. 1 from the substrate. Is.

  The means for supporting the first and second vibrators 10 and 11 of the detection unit 1C of the angular velocity sensor according to the present embodiment from the substrate includes first to fourth support beams 17, 18, 19, and 20. The first to fourth support beams 17, 18, 19, 20 support the first and second vibrators 10, 11 that are easy to displace in the X-axis direction and difficult to displace in the Y-axis and Z-axis directions. The first and second support beams 17, 18 and the third and fourth support beams 19 ′, 20 are arranged so as to be point-symmetric with respect to the X axis from the center of the elastic coupling beam 12.

That is, as understood from comparison with FIG. 1, in FIG. 1, the short side of the first vibrator 10 and the short side of the second vibrator 11 are connected by the elastic connecting beam 12. On the other hand, in the present embodiment, the short sides of the first vibrator 10 and the long sides of the second vibrator 11 are connected by the elastic connecting beam 12 ′, as described above, The first and second support beams 17 and 18 and the third and fourth support beams 19 and 20 that respectively support the second vibrators 10 and 11 are arranged so as to be symmetric with respect to each other from the center of the elastic coupling beam 12. ing. As a result, when the first and second vibrators 10 and 11 are vibrated by the first and second electrostatic force generation means 6 and 7 and the third and fourth electrostatic force generation means 8 and 9, respectively, The two vibrators 10 and 11 vibrate in a pendulum shape symmetrically with respect to each other from the center of the elastic coupling beam 12 ′ on a plane constituted by the X axis and the Y axis.

  Accordingly, the sum of the momentum and energy of the first and second vibrators 10 and 11 is 0, and the momentum and energy leaking from the detection element 1 through the silicon substrate 4 and the frame supporting the detection element 1 from the outside not shown in FIG. Becomes 0, and the vibrations of the first and second vibrators 10 and 11 can be prevented from leaking outside. As a result, the first and second vibrators 10 and 11 can be stably vibrated in a pendulum shape on the plane constituted by the X-axis and the Y-axis, so that the angular velocity detection accuracy can be improved.

  As described above, according to the present embodiment, (1) the beam supporting the vibrator receives a tensile force generated by the thermal stress from the substrate, and the resonance frequency of the vibrator is prevented from changing. The detection accuracy of angular velocity can be improved.

  (2) In addition, the vibration component in the Y-axis direction of the detection part of the vibrator that is caused by vibrating the vibrator in the X-axis direction, that is, other than the angular velocity, and the Y of the detection part of the vibrator due to the angular velocity. The vibration component in the axial direction can be detected by being distinguished by the frequency, and the angular velocity detection error can be reduced.

  (3) Further, the means for detecting the displacement of the detection portion of the vibrator in the Y-axis direction can also detect the displacement of the vibrator in the X-axis direction, thereby reducing the number of electrodes and reducing the chip area.

  (4) Further, the means for detecting the displacement of the detection portion of the vibrator in the Y-axis direction also detects the displacement of the vibrator in the X-axis direction, and the displacement of the vibrator in the X-axis direction is set to a predetermined value. Thus, the vibrator can be vibrated to improve the angular velocity detection accuracy.

  (5) Furthermore, it is possible to prevent the vibrations of the first and second vibrators 10 and 11 from leaking to the outside.

The angular velocity sensor of each embodiment of the present invention is used for vehicle side slip control, rear-end collision detection, rollover detection, vehicle traveling direction detection used in a navigation system, and the like.

It is a top view which shows the structure of the angular velocity sensor by the 1st Embodiment of this invention. It is A-A 'sectional drawing of FIG. FIG. 6A is a diagram schematically illustrating a cross-sectional view taken along line B-B ′ of the detection element 1 of the angular velocity sensor according to the first embodiment of the present invention. (B) simulates a cross-sectional view of a detection element of an angular velocity sensor in which a conventional vibrator 23 disclosed in Japanese Patent Application Laid-Open No. 2002-188923 is supported symmetrically from both sides by beams 22 and 24 from the substrate. FIG. (A) is a figure which represents the vibration direction of the 1st and 2nd vibrator | oscillators 10 and 11 of the angular velocity sensor of the 1st Embodiment of this invention in simulation. (B) is a diagram schematically representing the vibration direction of a vibrator of an angular velocity sensor in which a conventional vibrator disclosed in Japanese Patent Application Laid-Open No. 2002-188923 is supported symmetrically from both sides by a beam or the like from the substrate. is there. 1 is a drive circuit for an angular velocity sensor according to a first embodiment of the present invention. It is a top view which shows the structure of the angular velocity sensor by the 2nd Embodiment of this invention. It is a top view which shows the structure of the angular velocity sensor by the 3rd Embodiment of this invention. It is a top view which shows the structure of the angular velocity sensor by the 4th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1A, 1B, 1C ... Detection element, 2 ... Silicon layer, 3 ... Insulating layer, 4 ... Silicon substrate, 5 ... Glass substrate, 6 ... 1st electrostatic force generation means, 6a ... Frame, 6b ... Comb electrode, 6c ... pad, 7 ... second electrostatic force generating means, 7a ... frame, 7b ... comb electrode, 7c ... pad, 8 ... third electrostatic force generating means, 8a ... frame, 8b ... comb electrode, 8c ... pad, DESCRIPTION OF SYMBOLS 9 ... 4th electrostatic force generation means, 9a ... Frame, 9b ... Comb electrode, 9c ... Pad, 10 ... 1st vibrator, 10a ... Frame, 10b ... Detection part, 10c ... Connection beam, 10d ... Connection beam, 10e ... connecting beam, 10f ... connecting beam, 11 ... second vibrator, 11a ... frame, 11b ... detection part, 11c ... connecting beam, 11d ... connecting beam, 11f ... connecting beam, 11e ... connecting beam, 12, 12 '... Elastic connecting beam, 12a... Connecting beam, 12b Connecting beam, 13 ... first capacitance detecting means, 13a ... frame, 13b ... parallel plate electrode, 13c ... pad, 14 ... second capacitance detecting means, 14a ... frame, 14b ... parallel plate electrode, 14c ... pad 15 ... 3rd capacitance detection means, 15a ... Frame, 15b ... Parallel plate electrode, 15c ... Pad, 16 ... 4th capacitance detection means, 16a ... Frame, 16b ... Parallel plate electrode, 16c ... Pad, 17 ... 1st support beam, 17a ... Support beam, 17b ... Anchor part, 17c ... Pad, 18 ... 2nd support beam, 18a ... Support beam, 18b ... Anchor part, 18c ... Pad, 19, 19 '... 3rd support beam , 19a ... support beam, 19b ... anchor part, 19c ... pad, 20, 20 '... fourth support beam, 20a ... support beam, 20b ... anchor part, 20c ... pad, 21 ... frame part, 22 ... support beam 23 ... support beam, 24 ... support beam, 25 ... support beam, 31a ... oscillator, 31b ... inverter, 32 ... C / V converter, 33a ... multiplier, 33b ... LPF, 34a ... multiplier, 34b ... LPF, 35a ... multiplier, 35b ... LPF, 37a ... adder / subtractor, 37b ... amplifier, 37c ... multiplier, 37d ... adder, 37e ... inverter, 37f ... adder, 38a ... oscillator, 38b ... frequency divider, 39a ... Reference power source, 39b ... bias power source, 41 ... first auxiliary beam, 41a ... support beam, 41b ... support beam, 41c ... anchor portion, 41d ... anchor portion, 42 ... second auxiliary beam, 42a ... support beam, 42b ... support Beam, 42c ... Anchor part, 42d ... Anchor part

Claims (11)

First and second vibrators elastically supported on a substrate;
An elastic connecting beam for elastically connecting the first and second vibrators;
Driving means for oscillating the first and second vibrators in mutually opposite phases in the X-axis direction horizontal to the substrate surface;
Means for detecting a displacement in the Y-axis direction that is horizontal to the substrate surface of the detection portion of the first and second vibrators and perpendicular to the X-axis direction;
In the angular velocity sensor that detects the angular velocity based on the displacement in the Y-axis direction,
A supporting beam for supporting the first and second vibrators in a cantilever structure from one of the first and second vibrators, which is easy to displace in the X-axis direction and difficult to displace in the Y-axis and Z-axis directions. An angular velocity sensor comprising: The angular velocity sensor according to claim 1.
The angular velocity sensor, wherein the support beam supports the first and second vibrators at a plurality of locations. The angular velocity sensor according to claim 2, wherein
The long sides of the support beams that support the first vibrator at a plurality of locations are arranged to be parallel to each other,
The angular velocity sensor according to claim 1, wherein the long sides of the support beams that support the second vibrator at a plurality of locations are arranged to be parallel to each other. The angular velocity sensor according to claim 1.
The angular velocity sensor, wherein the support beam is disposed so as to support the first and second vibrators so as to be point-symmetrical from a central portion of the elastic coupling beam. The angular velocity sensor according to claim 1.
The angular velocity sensor, wherein the first and second vibrators are supported so as to vibrate in a pendulum shape within a plane constituted by the X axis and the Y axis. The angular velocity sensor according to claim 1.
It is easier to displace in the Z-axis direction perpendicular to the X-axis, the Y-axis, and the substrate surface than the support beam from the side opposite to the one where the support beam of the first and second vibrators is installed, An angular velocity sensor comprising an auxiliary beam for supporting the first and second vibrators. The angular velocity sensor according to claim 1.
A vibration component in the Y-axis direction of the detection portion of the first and second vibrators caused by vibrating the first and second vibrators in the X-axis direction, and the first and second driving An angular velocity sensor, comprising: a detection circuit that distinguishes and detects a vibration component in the Y-axis direction due to an angular velocity of a detection portion of a body by frequency. The angular velocity sensor according to claim 7,
The detection circuit includes:
The vibration component in the Y-axis direction of the detection portion of the first and second vibrators caused by vibrating the first and second vibrators in the X-axis direction is the first and second vibrations. A first detection circuit that performs synchronous detection at twice the frequency that causes the child to vibrate in mutually opposite phases in the horizontal X-axis direction with respect to the substrate surface;
The vibration component in the Y-axis direction due to the angular velocity of the detection portion of the first and second vibrators causes the first and second vibrators to vibrate in mutually opposite phases in the X-axis direction horizontal to the substrate surface. An angular velocity sensor comprising a second detection circuit that performs synchronous detection at a frequency. The angular velocity sensor according to claim 8.
An angular velocity sensor that detects displacement of the first and second vibrators in the X-axis direction by means for detecting displacement of the detection parts of the first and second vibrators in the Y-axis direction. . The angular velocity sensor according to claim 8.
The displacement in the X-axis direction of the first and second vibrators detected by the means for detecting the displacement in the Y-axis direction of the detection portion of the first and second vibrators is a predetermined value. An angular velocity sensor comprising drive means for vibrating the first and second vibrators. The angular velocity sensor according to claim 10.
The driving means is an electrostatic force generating means that applies an electrostatic force to the first and second vibrators and vibrates the first and second vibrators in opposite directions in the X-axis direction,
The means for detecting the displacement in the Y-axis direction of the detection portion of the first and second vibrators detects the displacement in the Y-axis direction of the detection portion of the first and second driving bodies as a change in capacitance. An angular velocity sensor characterized by being a capacitance detecting means.

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