JP3766730B2 - Energy-confined piezoelectric vibration gyroscope - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionmainlyFor gyroscope to detect rotational angular velocityAnd especially pressurePiezoelectric vibratory gyroscope using energy confinement vibration mode of electric vibratorThe
[0002]
[Prior art]
  Traditionally this kind ofPiezoelectric vibration gyroscope (below)SimplyThis is called a piezoelectric vibration gyro).didStatusAt pressureAround the axis in which the vibrator is perpendicular to its excitation directionTimesWhen rolling, EncouragementPerpendicular to the direction and axis of rotationNaCoriolis force generated in the direction is detectedBy timesDetects the angular velocity,ReluctantlyforThe field is known,Recently, for exampleSelfVehicle navigation systems and camera shake correction mechanisms for VTR camerasetcUsed forPleaseYes.
[0003]
  As a piezoelectric vibration gyro,For example, Japanese Patent Application Laid-Open No. 62-162915 and Japanese Patent Application Laid-Open No. 5-322580 includeShakeMovingEnergy confinement using a piezoelectric vibrator oscillating in an energy confined vibration mode where energy is concentrated near the drive electrodeMoldPiezoelectric vibration gyroProposedIt has been proposed.
[0004]
  like thisEnergy confinementTypePiezoelectric vibratory gyros are easy to support the piezoelectric vibrator because vibration energy is concentrated in the local area of the piezoelectric vibrator, and there is no need for a loose lead wire.SayThere are advantages.
[0005]
  JP 62-162915 AsoIn order to confine the vibration energy locally, the vibrator is made thick locally.,The part is polarized in the thickness direction, a drive electrode is provided on the opposite end face of the thick local area, and a detection electrode is provided on the opposite side face. As another example, a drive electrode and a detection electrodeWhenIs provided on one surface of a piezoelectric plate, and a cross finger electrode is provided as a detection electrode between drive electrodes.
[0006]
  JP-A-5-322580soIs a part of the piezoelectric plate that is polarized in the thickness direction, and two sets of counter electrodes are provided on the main surface of the polarization region with the opposing directions at right angles, with one counter electrode serving as the drive electrode and the other facing A piezoelectric vibration gyro using an electrode as a detection electrode is disclosed.
[0007]
[Problems to be solved by the invention]
  In the conventional piezoelectric vibration gyro described above, when the piezoelectric plate is excited by a pair of drive electrodes in a direction perpendicular to the polarization direction of the piezoelectric plate, and the rotation of the polarization direction is applied, the polarization directionas well asVibration caused by Coriolis force generated in a direction perpendicular to the excitation direction is detected by a pair of detection electrodes.ByRotation speed is detected but piezoelectric vibration gyroPolarization direction with respect toIf acceleration other than the rotation of is applied, it will affect the vibration of the piezoelectric plate.End upAs a result, an error occurs in the detection speed.ThatThere are drawbacks.
[0008]
  orDisclosed in Japanese Patent Laid-Open No. 62-162915IsConfined energyMold pressureIn an electrovibration gyro, the thickness of the piezoelectric plate must be increased locally.OrThere is a manufacturing difficulty that a cross finger electrode has to be formed. Also, a pair of drive electrodesAgainstSince the pair of detection electrodes are provided in the vicinity of each other, the drive electric field applied from the drive electrode to the piezoelectric plate is affected by the detection electrode, and the accuracy of the drive electric field changes due to the change of the drive electric field direction.It will becomeThere are drawbacksAhThe
[0009]
  In addition,Disclosure in JP-A-5-322580IsConfined energyMold pressureElectro-vibration gyro is composedButA pair of drive electrodes that are simple and easy to manufactureAgainstSince a pair of detection electrodes are provided in the vicinity of each other, the drive electric field applied from the drive electrode to the piezoelectric plate is affected by the detection electrodes, and the drive electric field direction changes.ByIt is difficult to obtain accurate detection outputThere is a disadvantage.
[0010]
  BookInventionIt was made to solve these problems, and the technical problem is that it has a simple small structure.It is affected by the acceleration applied to the piezoelectric diaphragm.Can be detected with high accuracyEnergy confinementMold pressureProviding an electrovibration gyroInThe
[0011]
  or, The present inventionOther technical challengesIn a limited area on the main surface of the piezoelectric plateLeaveEnergy confinement that prevents the output electrode from adversely affecting the drive electric field by sharing the output electrode as part of the drive electrodeMold pressureProviding an electrovibration gyroIt is in.
[0012]
[Means for Solving the Problems]
  According to the present invention, a pair of drive electrodes and a pair of detection electrodes are formed on the main surface of a region having polarization in the thickness direction of the piezoelectric plate, and the pair of drive electrodes is used to make a perpendicular to the polarization direction. An electric field is applied in a direction parallel to the principal surface of the direction to excite thickness shear vibration in a predetermined direction in the piezoelectric plate and perpendicular to the predetermined direction generated by Coriolis force using the pair of detection electrodes A piezoelectric vibration gyro using energy trapping vibration configured to detect thickness shear vibration in any direction,On one main surface of the piezoelectric plate, there are a drive electrode and a detection electrode.The first electrode set is formed and the thicknessOnlyOn the other main surface opposite to one main surface in the direction, Comprising the drive electrode and the detection electrodeThe second set of electrodes is the first set of electrodesFormed in a position opposite to the plane symmetryHas beenThe second1 electrode assemblySecond2 electrode pairsThe electrodes facing each other in the thickness direction areAn energy confinement type piezoelectric vibration gyro which is electrically connected is obtained.
[0013]
  According to the present invention, in the energy confinement type piezoelectric vibration gyro, the first electrode pair is one of two positions separated from each other at a predetermined interval in a predetermined direction on one main surface. The strip-shaped first electrode provided at a position extending in a direction perpendicular to the predetermined direction and the other position provided so as to be spaced apart from each other in a direction substantially perpendicular to the predetermined direction. The strip-shaped second electrode and the third electrode are formed on the other main surface so as to face the first electrode, the second electrode, and the third electrode, respectively. A strip-like fourth electrode, a fifth electrode, and a sixth electrode provided at positions, the first electrode, the second electrode, and the third electrode being respectively opposed to the fourth electrode, Electrically conductive connection to the fifth electrode and the sixth electrode Furthermore, a driving voltage for excitation is applied between the first electrode, the second electrode, and the third electrode, and a Coriolis force generated between the second electrode and the third electrode. An energy confinement type piezoelectric device using an energy confinement mode of thickness shear vibration generated between the first electrode, the second electrode and the third electrode so as to detect an electromotive force corresponding to the vibration due to A vibrating gyro is obtained.
[0014]
  Further, according to the present invention, in the energy confinement type piezoelectric vibration gyro, the second electrode and the third electrode are respectively connected to the first current detection circuit and the second current detection circuit each having a virtual ground function. The detection output is obtained from the difference voltage generated between the outputs of the first current detection circuit and the second current detection circuit by applying an excitation drive voltage to the first electrode. A configured energy confinement type piezoelectric vibration gyro is obtained.
[0015]
  In addition, according to the present invention, in the energy-confined piezoelectric vibration gyro, the first current detection circuit and the second current detection circuit are connected between outputs of the first current detection circuit and the second current detection circuit. Differential circuit for detecting the output voltage difference in the current detection circuit, and differential circuit output A synchronous detection circuit connected to the output of the synchronous detection circuit, a rectifier circuit connected to the output of the synchronous detection circuit, and a signal of a self-excited drive frequency connected between the outputs of the first current detection circuit and the second current detection circuit. An energy-confined piezoelectric vibration gyro comprising an oscillation circuit for oscillation and a drive circuit that is connected to the output of the oscillation circuit and applies an alternating voltage with a self-excited drive frequency to the first electrode is obtained..
[0016]
  On the other hand, according to the present invention, in any one of the energy confinement piezoelectric vibration gyros described above, the piezoelectric plate is made of piezoelectric ceramics, and the piezoelectric ceramics include the first electrode to the third electrode.MuOnly the region from the first electrode to the third electrode is thick.OnlyAn energy-confined piezoelectric vibration gyro that is polarized in the direction is obtained.
[0017]
  otherOn the other hand, according to the present invention, in any one of the energy confinement piezoelectric vibration gyros described above, an energy confinement piezoelectric vibration gyro using a piezoelectric crystal plate having a polarization axis in the thickness direction can be obtained.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
  FIG. 1 shows a piezoelectric vibrator provided in an energy confinement type piezoelectric vibrating gyroscope according to an embodiment of the present invention.1It is an external appearance perspective view which shows the basic composition. Referring to FIG. 1, the piezoelectric vibrator 1 uses, for example, a piezoelectric ceramic plate such as PZT or barium titanate and has a thick central portion.OnlyIt consists of a piezoelectric plate 10 having a polarization axis in the direction. A strip-shaped first electrode 11 is provided on one main surface (front surface) of the central portion of the piezoelectric plate 10, and the first electrode 11 is located at a predetermined distance from the first electrode 11. The second electrode 12 and the third electrode 13 are formed apart from each other in parallel. These first electrode 11, second electrode 12, and third electrode 13 are connected to terminal portions 14, 15, and 16 for leading to the outside, respectively.
[0019]
  orOf the piezoelectric plate 10The other main surface (Back side)A similar suTripIn shape4thElectrode 21, Fifth electrode22, Sixth electrode 23To face the first electrode 11, the second electrode 12, and the third electrode 13.Plane symmetrySet in shapeIt isThese fourthElectrode 21, Fifth electrode22, Sixth electrode23About eachTerminal portion 24 for leading to the outside,25,26 is connected.
[0020]
  still,theseofelectrode11-13, 21-23 andTerminal section14-16, 24-26The silver pasteOrConsists of gold spatterExcept for the case whereOther conductive films can be employed. Terminal part for leading outAbout 14-16, 24-26Is,Vibrator(Piezoelectric plate 10)Use lead wires without providing aboveAs a configurationAlso good.
[0021]
  OneMain surface electrode 11~ 13 andThe other main surfaceElectrode 21~ 23 is thatEach otherIt is electrically connected. The terminal portion 14 is used for this conductive connection.,15,16 and terminal part 24,25,26 and thatEach otherIt can be performed by connecting with an external conductor. In this case, a means using an external conductor is adopted.To do, pressureElectrical board10The corresponding terminals on the front and back sides(14-24, 15-25, 16-26)Forming a conductive film so as to conduct electricity,ForTerminals(14-24, 15-25, 16-26) orversusForElectrodes(11-21, 12-22, 13-23)A through hole for connecting the piezoelectric plate 10 is provided in the piezoelectric plate 10thing,Terminal section14-16, 24-26As a lead wireIn each casePair of lead wiresForWhat to do externallyAll of these methods are adoptedMay be.
[0022]
  FigureIn the example shown in 1IsIn the piezoelectric plate 10Thickness direction is Z axis, electrode11-13, 21-233D coordinates with the opposite direction of X axis as the X axis and the direction perpendicular to these as the Y axisSetThe
[0023]
  Therefore, in the case of this piezoelectric vibrator 1, in the piezoelectric plate 10First electrode 11 andSecondElectrode 12 and third electrodeBetween 13(Or between the fourth electrode 21, the fifth electrode 22, and the sixth electrode 23)When a drive voltage (alternating current) is applied to, vibration in the X direction is excited. This statePressureWhen the electric plate 10 rotates around the Z axis, vibration due to the Coriolis force is generated in the Y direction.Electrode 12 and third electrode 13(Or(Between the fifth electrode 22 and the sixth electrode 23)An electromotive force is generated. By detecting this electromotive force, the magnitude of vibration due to Coriolis forceThat is,The rotational angular velocity can be detected.
[0024]
  At this time, when an acceleration having a Z direction component is applied to the piezoelectric plate 10 from the outside, the vibration of the piezoelectric plate 10 is affected. This effect is caused by the surface of the piezoelectric plate 10.surfaceAnd backFace andThen, since it becomes an antiphase, both sidessurfacePairs established inForElectrodeTo each other (11-21, 12-22, 13-23)By connecting, the influence of acceleration is canceled out.
[0025]
  As described above, the vibration energy is confined in the central portion of the piezoelectric plate 10 and does not reach the periphery, so that it is easy to support the peripheral portion of the piezoelectric plate 10. In addition, for each of the electrodes 11 to 13 and 21 to 23 described above, in other words,As for each of the electrodes 11 to 13 on one main surface of the piezoelectric plate 10, the first electrode 11 is a drive electrode, the second electrode 12 and the third electrode 13 are detection electrodes, as will be described later. In addition, the fourth electrode 21 is driven for each of the electrodes 21 to 23 on the other main surface opposite to the one main surface in the thickness direction as a set of first electrodes. And the fifth electrode 22 and the sixth electrode 23 are detection electrodes and are formed in the polarization region as a set of second electrodes, and further, the set of second electrodes is the first set of electrodes. The electrodes opposed to each other in the thickness direction in the first electrode set and the second electrode set are formed at positions facing the electrode set in plane symmetry.It is configured to be electrically conductively connected.
[0026]
  Figure 2, A circuit showing a configuration of an electric circuit connected to the piezoelectric vibrator 1 described aboveIt is a block diagram. Referring to FIG. 2, the piezoelectric vibrator 1Second electrode 12, thirdThe electrode 13 includesEach with a virtual ground functionCurrent detection circuit 31, Second current detection circuit32ContactIt has been continued.These firstCurrent detection circuit 31, Second current detection circuitOn the output side of 32,To detect the difference in output voltage between these circuits.differenceMovementRoad 33 is connected,Connected to the output of the differential circuit 33Synchronous detection circuit 34,Connected to the output of the synchronous detectorA detection output of the piezoelectric vibration gyro is obtained via the rectifier circuit 35. on the other hand,FirstCurrent detection circuit 31, Second current detection circuit32Between outputsSatisfy the self-excited oscillation condition.Therefore, to oscillate the signal of self-excited drive frequencyOscillation circuit 36ButConnected,To the output of the oscillation circuit 36IsAC voltage of self-excited drive frequency is applied to the first electrode11Applied toX directionInFor giving vibrationDrive circuit 37 is connectedThe self-excited oscillation circuit is configured. This self-excited oscillation circuitA driving voltage for excitation is applied to the first electrode 11 (an AC voltage having a frequency substantially equal to the resonance frequency of the thickness shear vibration of the piezoelectric vibrator 1 is applied to the electrode 11), and the first current detection circuit A detection output can be obtained from a difference voltage generated between the output of the first current detection circuit 31 and the second current detection circuit 32.
[0027]
  3 is the same as FIG.The first provided in the electric circuitCurrent detection circuit 31, Second current detection circuit32A specific example of the circuit configuration is shown.thisCurrent detectionCircuitWith the function of virtually grounding the second electrode 12 and the third electrode 13,The non-inverting input terminal (+) of the operational amplifier 41 is grounded to the reference voltage, and the output terminal of the operational amplifier 41VoutTo inverted input terminal(-) IIs connected to the resistor R. Inverted input terminal (-)iIs always due to the virtual grounding function of the operational amplifier.Close toThe ground reference potential is maintained. This inversioninputTerminal(-) IWhen a current flows in, it is converted to a voltage by resistor RFrom the output terminal VoutOutput Vout = -iRButGainIsTheThat is, hereThe current detection circuit is functionallyPowerImpedance is almost zero and output voltage proportional to input current can be obtained.What can be doneIt is.
[0028]
  thislikeFig. 2 shows the current detection circuit.In the electrical circuit shown inofFirstCurrent detection circuit 31,Second current detection circuitUsed for 32When, Inverting input terminal (-)iThe second electrode12, third electrode13 is connected. As a result, the driving voltage is applied to the first electrode 11 and the second electrode.12, third electrode13 and the second electrode12, third electrodeThe electromotive force between 13 isFirstCurrent detection circuit31, second current detection circuitIt can be detected as a potential difference between the 32 outputs.
[0029]
  Next, the piezoelectric vibrator in the above embodiment of the present invention1The driving principle will be specifically described with reference to the drawings.
[0030]
  FIG.IsEnergy confinement type shown in FIG. 1 and FIG.PiezoelectricVibrator1A and 1B show a basic structure of a piezoelectric plate 10 with simplified electrodes for explaining the driving principle of FIG. 1, in which FIG. 1A relates to a plan view, and FIG. It is related with the side surface sectional view which showed only the electrode part except the terminal part.4A and 4B, on the same surface of the central portion of the piezoelectric plate 10 polarized in the thickness direction (Z-axis direction).Is, A slit-shaped electrode D1 facing each other with a gap in the X-axis direction,D2 isExtending in the Y directionFormed,Terminal portions T1 and T2 are connected to the outside in the X direction perpendicular to the extending direction.Thehere,TerminalPartT1, TWhen a voltage is applied between the two electrodes D1 facing each other, DSince the electric field in the direction (X direction) substantially parallel to the plane of the plate is applied to the region (interelectrode region) of the piezoelectric plate 10 between the two, the thickness direction (Z-axis direction) orthogonal to the electric field is applied. Due to the interaction with the polarization of the electrodeD1, D2In the X directiondistortionWill occur. Electrode D1,Design the dimensions of D2 according to the characteristics of the piezoelectric plate 10, and apply the applied voltage to the electrodes.D1, D2If the AC voltage has a frequency that matches the resonance frequency of theD1, D2Thickness-slip vibration can be excited in the inter-region. The vibration is an electrodeD1, D2Attenuated and confined without propagating around the interspaceSoAn energy confining oscillator can be constructed.In addition, at this timeVibration is a piezoelectric plate10This is referred to as parallel electric field excitation type thickness shear vibration.By the way, Thickness shear vibration is a piezoelectric plate10The direction of displacement is parallel to the plate surface, and the wave propagation direction is vibration in the thickness direction of the plate..
[0031]
  FIG. 5 shows a displacement distribution in the thickness direction (Z-axis direction) when resonating at a half wavelength in order to illustrate the state of thickness shear vibration in the piezoelectric plate 10 described above.FIG.as well asFIG.Pointing out toungueThe piezoelectric vibrator 1 isThe driving principle described aboveUsedOn the basic structureFirst electrode 11Is electrode D1,Second electrode 1 facing this2nd3 electrodes 13Is electrode D2Corresponding toElectrode D2 isThe second electrode 12 is divided into two to form a detection electrode.,The third electrode 13 is configured and each has a virtual ground functionFirstCurrent detection circuit 31,Second current detection circuit32. Thus, the second electrode 12,Since the third electrode 13 is virtually maintained at the reference potential, it can be regarded as a ground terminal in terms of potential. Therefore, the pressure is not applied to the first electrode 11.Electric vibrator 1When a driving voltage for excitation having a frequency substantially equal to the resonance frequency of the thickness shear vibration mode is applied,In the case of the piezoelectric plate 10 described in FIGS. 4 (a) and 4 (b)alike,A first electrode 11, a second electrode 12, a third electrode 13,In the region surrounded by (interelectrode region), the center of the first electrode 11 and the second electrode12, third electrodeThe thickness shear vibration of the energy confinement vibration mode in the direction of the straight line (X direction) connecting the midpoints of the straight lines connecting the centers of 13 occurs.
[0032]
  This stateWith the piezoelectric vibrator 1When rotated around an axis perpendicular to the principal surface, the Coriolis force acts, EncouragementA thickness shear vibration in a direction (Y direction) perpendicular to the direction of the thickness shear vibration being oscillated occurs. The first electrode 11 is caused by the thickness shear vibration generated by the Coriolis force.as well asBetween the second electrodes 12The second1 electrode 11as well asThird electrode 1ThreeAs a result, the impedance betweenFirstCurrent detection circuit 31,Second current detection circuitThe value of the current flowing into 32 changes. Second electrode 12,The third electrode 13 isUpAs mentioned above, it is symmetrical with respect to the direction of thickness shear vibration (X direction) being excited.formIs placed inFirstCurrent detection circuit 31,Second current detection circuitThe currents that change due to the vibration caused by the Coriolis force flowing into 32 are equal in amplitude and different in phase from each other by 180 degrees. Therefore,FirstCurrent detection circuit 31,Second current detection circuitThe output voltage of 32 also becomes a voltage having a phase difference of 180 degrees from each other, the difference between these output voltages is detected as a differential voltage by the differential circuit 33, and this voltage is synchronously detected at a predetermined timing by the synchronous detection circuit 34. By rectifying by the rectifier circuit 35, a DC output voltage proportional to the applied rotational angular velocity can be obtained as a detection output.
[0033]
  on the other hand,FirstCurrent detection circuit 31,Second current detection circuitReference numeral 32 denotes an oscillation circuit 36 and a vibrator drive circuit 37 for satisfying the self-excited oscillation condition.WhenThroughFirstIt is connected to the electrode 11 to constitute a self-excited oscillation loop. As a result, the resonance frequency of the piezoelectric vibrator 1 is automatically adjusted to improve efficiency.Piezoelectric wellThe vibrator 1 can be drivenForHighly sensitive gyro can be obtained.
[0034]
  UpIn the case of the example described, one of the piezoelectric plates 10Main faceOn the (surface)CanFirstElectrode 11And the second electrode 12 and the third electrode 13Described the operation, but othersOne ofOn the main surface (back surface)The fourth electrode 21, the fifth electrode 22, and the sixth electrode 23 in FIG.electrode11-Symmetric with 13formAre connected to each otherByOn one main surfaceeachelectrodeIn the case of 11-13Same aslikeWill work.
[0035]
  Furthermore, for the piezoelectric plate 10When acceleration in the Z-axis direction is applied, this effectIn the firstElectrode 11, SecondImpedance between electrodes 12And the firstElectrode 11, ThirdThe impedance between the electrodes 13 changes. ThisHereIf the impedance change ofOneA set of main surface sideFirstElectrode 11,SecondElectrode 12And the third electrodeEven if only 13, the error is canceled in the differential amplifier circuit 33.筈It is. However, due to accelerationRepulsionSince the overall amplitude of the dynamic vibration changesOneOnly the electrode on the main surface side cannot be canceled and an error remains. On the contrary,On the other main sideOn the back4thElectrode 21,5th electrode22And the sixth electrode23, the change in impedance between the electrodes on the back surface due to the influence of acceleration is opposite in phase to the change in impedance between the electrodes on the front surface.eachelectrode11-13And on the backeachelectrode21-23WhenofSymmetryformBy electrically connecting such things, the impedance changes of opposite phases are added and canceled. Thereby, a highly accurate piezoelectric vibration gyro that is not affected by acceleration can be realized.
[0036]
  FIG.Substituted for the electric circuit shown in FIG.Shows other circuit configurationsFIG. Referring to FIG.The first electrode 11 is grounded, and the secondElectrode 12, third electrode 13Resistance R1 between,A voltage dividing circuit composed of a series circuit of R2 is connected, and the oscillation driving circuit 38 is controlled by the divided voltage. This oscillation drive circuit38Is groundedAnd,to thisSo second1 electrode 11 and second electrode12 andThird electrode13A driving voltage is applied between the two.In addition, hereThe oscillation drive circuit 38 is shown in FIG.Provided in the electrical circuit shown inFrom the oscillation circuit 36 and the drive circuit 37CompletionIs. Both ends of the voltage dividing circuit are connected to the differential amplifier circuit 33.Including this differential amplifier circuit 33,Detection circuit 34as well asThe rectifier circuit 35 is shown in FIG.For the electrical circuit shown inIt is the same.
[0037]
  By the way,Piezoelectric plate used in the present invention10“Having polarization in the thickness direction” is not limited to being polarized only in the thickness direction, but includes those having a polarization component in the thickness direction.Of course,Since a larger polarization component in the thickness direction is better, the one polarized only in the thickness direction is most advantageous.
[0038]
  When piezoelectric ceramics are used as the piezoelectric plate 10, polarization processing is required as is well known, but the polarization region is10It may be possible to extend over the entire area, or to be limited only to the region where vibration is confined.
[0039]
  As the piezoelectric plate 10, a piezoelectric crystal plate (for example, quartz crystal, LiNbO)₃, LiTO₃Etc.) can be used. In that case, in order to have a polarization axis in the thickness direction, a Z-cut plate is most preferable, but a rotating Y-cut plate can also be used.
[0040]
【The invention's effect】
  As mentioned above,The present inventionPiezoelectric vibration gyroAccording to X direction driveas well asA pair of electrodes for detecting Y-direction vibration is symmetrical on both sides of the piezoelectric plate in the thickness direction of the piezoelectric plate.To be in shapeConnect the corresponding electrodes of the front and back electrode pairs to each other.YSince the output signal of the Y direction vibration is obtained from the electrode for detecting the direction vibration, the influence on the vibration when the acceleration is applied to the piezoelectric vibrator is canceled by the conductive connection of the front and back electrodes.It will beInfluence of acceleration applied to the piezoelectric vibratorDuplicateCancel without using miscellaneous circuitsTo doIf possibleboth,It can generate an electric field more efficiently than excitation / detection of vibration with a surface-only electrode., YuiFruitAsHigh sensitivityThe diGyroTo get the characteristicsThe
[0041]
  or, The present inventionIn case of piezoelectric vibration gyroOf piezoelectric plateBoth sidesA pair ofoppositeDrive using only slit electrodes,And on both sides of the piezoelectric plateDivided into twoA pair of opposing electrodes separated from each other (each electrode is in a parallel state)Since detection is performed as a detection electrode, the drive electric field is not adversely affected by the presence of the detection electrode, and the Y-direction vibration can be detected while maintaining the electric field for exciting the X-direction vibration.For,High precisionsoHigh sensitivityThe diGyroCharacteristics can be obtained, andUsing energy-confined vibrationforEasy to support and reliable gyroTo get the characteristicsThe
[Brief description of the drawings]
FIG. 1 of the present inventionOneEmbodimentEnergy confinement type piezoelectric vibration gyroOf piezoelectric vibratorsBasicShow configurationappearanceIt is a perspective view.
[Figure 2]A circuit showing a configuration of an electric circuit connected to the piezoelectric vibrator described in FIG.It is a block diagram.
FIG. 3 is a diagram of FIG.Provided in electrical circuitsCurrent detection circuitThis is a specific example of the circuit configuration.
[Fig. 4]1A and 1B show the basic structure of a piezoelectric plate with simplified electrodes to explain the driving principle of the piezoelectric vibrator described in FIG. 1, wherein FIG. 1A relates to a plan view, and FIG. It is related with the side surface sectional view which showed only the electrode part except the terminal part.
[Figure 5]In order to illustrate the state of thickness shear vibration in the piezoelectric plate shown in FIG. 4, the displacement distribution in the thickness direction (Z-axis direction) when resonating at half wavelength is shown.
[Fig. 6]Substituted for the electric circuit shown in FIG.Shows other circuit configurationsCircuitIt is a block diagram.
[Explanation of symbols]
    1 Piezoelectric vibrator
    10 Piezoelectric plate
    11-13, 21-23 Electricvery
    14,15,16, 24, 25, 26  Terminal section
    31, 32  Current detection circuit
    33 Differential circuit
    34 Synchronous detection circuit
    35 Rectifier circuit
    36 Oscillator circuit
    37 Drive circuit
    38 Oscillation drive circuit
    41 operational amplifier

Claims (6)

A pair of drive electrodes and a pair of detection electrodes are formed on the main surface of a region having polarization in the thickness direction of the piezoelectric plate, and the main surface in a direction perpendicular to the polarization direction is formed using the pair of drive electrodes. A thickness shear vibration in a direction perpendicular to the predetermined direction generated by the Coriolis force is generated by applying an electric field in a parallel direction to excite thickness shear vibration in a predetermined direction in the piezoelectric plate. A piezoelectric vibration gyroscope using energy confinement vibration configured to detect the first electrode on one main surface of the piezoelectric plate is a first electrode set including the driving electrode and the detection electrode. together are formed over a substrate wherein the thickness opposite side of the other on the main surface and said one main surface in the direction, the second set of electrodes consisting of the driving electrodes and detection electrode is the first a position opposed to the set and plane symmetry of the first electrode It is formed, the set and the electrode facing each other in the thickness direction which are in the set of second electrodes of the first electrode, energy-trap, characterized in that formed by electrically conductive connection Piezoelectric vibration gyroscope.   2. The energy confinement type piezoelectric vibrating gyroscope according to claim 1, wherein the first set of electrodes is one of two positions separated from each other at a predetermined interval in the predetermined direction on the one main surface. The strip-shaped first electrode provided at a position extending in a direction perpendicular to the predetermined direction and the other position provided so as to be spaced apart from each other in a direction substantially perpendicular to the predetermined direction. A strip-shaped second electrode and a third electrode, and the second electrode set includes the first electrode, the second electrode, and the third electrode on the other main surface. It consists of a strip-like fourth electrode, a fifth electrode, and a sixth electrode provided at positions facing the electrodes, respectively, and the first electrode, the second electrode, and the third electrode are: The fourth electrode facing each other, front Electrically conductively connected to the fifth electrode and the sixth electrode, and further, an excitation drive between the first electrode, the second electrode, and the third electrode A voltage is applied, and an electromotive force corresponding to vibration caused by Coriolis force generated between the second electrode and the third electrode is detected, so that the first electrode, the second electrode, and the second electrode are detected. An energy confinement type piezoelectric vibration gyroscope using an energy confinement vibration of a thickness shear vibration generated between three electrodes.   3. The energy confinement type piezoelectric vibration gyroscope according to claim 2, wherein the second electrode and the third electrode are connected to a first current detection circuit and a second current detection circuit each having a virtual ground function. And applying a drive voltage for excitation to the first electrode so as to obtain a detection output from a difference voltage generated between the outputs of the first current detection circuit and the second current detection circuit. An energy confinement type piezoelectric vibration gyroscope characterized by being constructed.   4. The energy confinement type piezoelectric vibration gyroscope according to claim 3, wherein the first current detection circuit and the second current detection are connected between outputs of the first current detection circuit and the second current detection circuit. A differential circuit for detecting a difference in output voltage in the circuit; a synchronous detection circuit connected to the output of the differential circuit; a rectifier circuit connected to the output of the synchronous detection circuit; and the first current An oscillation circuit connected between the output of the detection circuit and the second current detection circuit for oscillating a signal of the self-excitation drive frequency, and an alternating current of the self-excitation drive frequency connected to the output of the oscillation circuit An energy confinement type piezoelectric vibration gyroscope comprising: a drive circuit for applying a voltage to the first electrode. The energy confinement type piezoelectric vibration gyroscope according to any one of claims 1 to 4, wherein the piezoelectric plate is made of piezoelectric ceramics, and the piezoelectric ceramics includes a gap between the first electrode and the third electrode. energy-trap piezoelectric vibrating gyroscope, characterized in that only the region near the electrodes of including the first electrode to the third is polarized in the thickness direction.   5. The energy confinement type piezoelectric vibrating gyroscope according to claim 1, wherein the piezoelectric plate is a piezoelectric crystal plate having a polarization axis in the thickness direction. Type piezoelectric vibration gyroscope.

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