JPH11264730A - Electromagnetic drive type angular velocity sensor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic drive type angular velocity sensor capable of detecting angular velocity with high accuracy by a simple structure. SOLUTION: A glass substrate 11, a vibrator 20 disposed on an upper surface of the glass substrate 11, and a permanent magnet 12 mounted on an under surface of the glass substrate 11, form a three-layer structure. The vibrator 20 is equipped with a substantially square vibrator weight 21 formed to have four sides each supported in midair by two support beams 22 and metallic wires 21a formed on a surface of the vibrator weight 21 so as to connect two support beams neighboring each other on each side. Each support beam is formed into an L-shape so as to have a part extending vertically from each side of the vibrator and a part being bent at a right angle at an end thereof and extending therefrom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an angular velocity sensor for detecting an angular velocity of an object, and more particularly to an electromagnetically driven angular velocity sensor and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as an angular velocity sensor, for example, an angular velocity sensor having a configuration as shown in FIGS. 12 and 13 is known. First, an angular velocity sensor 1 shown in FIG. 12 is an electromagnetic drive / piezoresistive detection type angular velocity sensor.
As shown in FIG. 1A, a glass substrate 3, a silicon substrate 4, a glass substrate 5 and a permanent magnet 6 are sequentially placed on a base 2. Here, as shown in FIG. 12B, the silicon substrate 4 includes two vibrators 4a and 4b formed so as to be parallel to each other in a horizontal plane. 4b is an outer frame portion 4d through two thin rod-shaped connecting portions 4c at both ends.
Linked to Further, these connecting portions 4c
Of these, the inner connecting portion 4c has a piezoresistor 4e for detection formed on the surface thereof. FIG.
In (B), the z-axis is the direction of the detected vibration, and the x-axis is the direction of the driving vibration.

According to the angular velocity sensor 1 having such a configuration, a drive current is applied to the vibrators 4a and 4b as shown by an arrow I in FIG.
When the vibrators 4a and 4b vibrate by receiving an angular velocity in a state where b is driven electromagnetically, the vibrators 4a and 4b are formed on the surface of the connecting portion 4c by the stress applied to the connecting portion 4c by the longitudinal vibration in the z-axis direction. The resistance value of the piezo resistor 4e changes.
This change in resistance value is measured, for example, as a change in current value.
Through the processing, the angular velocity applied to the vibrators 4a and 4b is detected.

The angular velocity sensor 7 shown in FIG. 13 is an electrostatic drive / capacity detection type angular velocity sensor, and a pair of glass substrates 7a and 7b disposed in parallel with each other.
And a vibrator 8 disposed between the glass substrates 7a and 7b, and has a three-layer structure. As shown, the angular velocity sensor 7 includes a torsion bar 8b of an angular velocity detection beam extending inward in the horizontal direction and having both ends supported by an outer frame portion 8a.
weights 8d and 8 supported at both ends of two cantilever beams 8c of a driving beam that extend obliquely crossing each other from the center of b.
The vibrator 8 is composed of the elements e and e, and electrodes are formed on the upper and lower surfaces of the weights of these vibrators. Here, the vibrator weight 8d is disposed on one side of the torsion bar 8b, and the vibrator weight 8e is disposed on the other side. On the other hand, the glass substrates 7a and 7b
Electrostatic drive electrodes 7c, 7d and electrostatic drive monitor electrodes 9a, 9b facing the weight 8d of the vibrator and capacitance detecting electrodes 7e, 7f facing the weight 8e of the vibrator are provided on the inner surfaces facing each other. And

According to the angular velocity sensor 7 having such a configuration, a driving voltage supplied from a power source (not shown) is applied to the electrostatic driving electrode, and the vibrator weight 8d is driven and vibrated by electrostatic force. At this time, the weight 8e of the vibrator supported on the opposite side of the cantilever 8c also vibrates similarly.
In this state, when the vibrator vibrates by receiving the angular velocity,
The distance between the weight 8e of the vibrator and the capacitance detection electrodes 7e and 7f fluctuates, and the capacitance between them changes. The change in capacitance is appropriately measured and processed to detect the angular velocity of the vibrator.

[0006]

However, the angular velocity sensors 1 and 7 configured as described above have the following problems to be solved. That is, in the angular velocity sensor 1, the piezoresistor 4e is formed on the surface of the connecting portion 4c supporting the two vibrators 4a and 4b, and the glass substrate 3, the silicon substrate 4, the glass substrate 5 and the permanent magnet 6 In some cases, the structure is complicated because of the four-layer structure, and the manufacturing cost is increased. Further, since the vibration modes of the driving vibrations of the vibrators 4a and 4b and the detection vibration based on the angular velocity to be detected are different, it is necessary to adjust the resonance frequency of these vibrations, which increases the cost.

On the other hand, in the angular velocity sensor 7 shown in FIG. 13, an external element is unnecessary because the weight 8d of the vibrator is electrostatically driven, but when a large driving voltage is applied, the weight of the vibrator is reduced. Since the influence of the structural imbalance of 8d becomes large and the weights 8d and 8e of the vibrator collide with the opposing drive electrodes, the drive amplitude is reduced to avoid such collision. Therefore, there is a problem to be solved that the detection accuracy of the angular velocity is low. Also, in the case of the angular velocity sensor 7, similarly to the angular velocity sensor 1, since the resonance frequencies of the driving vibration of the vibrators 4 a and 4 b and the detection vibration based on the angular velocity to be detected are different, the adjustment operation for adjusting these resonance frequencies is performed. However, there is a problem that the cost is increased. Further, since the entire angular velocity sensor 7 detects the capacitance of the vibration of the vibrator weight 8e, it is necessary to narrow the gap between the vibrator weight 8e and the capacitance detecting electrodes 7e and 7f. Therefore, it is necessary to vacuum seal the vibrator in order to eliminate the influence of air damping, and there has been a problem that the cost increases.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide an electromagnetically driven angular velocity sensor and a method of manufacturing the same, which can detect an angular velocity with high accuracy with a simple configuration.

[0009]

In order to achieve the above object, an electromagnetically driven angular velocity sensor according to the present invention has the following features.
The described invention is a vibrator having a symmetrical weight formed with electrode wiring, a plurality of supporting beams for elastically supporting the weight at symmetrical positions, and a magnet for applying a uniform magnetic field to the weight. A substrate having a vibrator on the upper surface side and a magnet on the lower surface side, and a support for driving vibration in which an electric wiring formed on the upper surface by one support beam and an electrode wiring of the weight are formed in one electric circuit. This is a support beam for detection vibration, in which electric wiring and weight electrode wiring formed on the upper surface by another support beam are formed in one electric circuit. The Lorentz force acts on the vibrator weight and vibrates, and the Coriolis force acts upon the application of angular velocity and the vibrator weight vibrates in the direction perpendicular to the direction of the Lorentz force. Both ends of the support beam It was configured to detect the angular velocity is detected. Further, in addition to the above configuration, the weight of the vibrator is substantially square, and the width of the support beam for driving vibration and the width of the support beam for detection vibration are the same. And has high sensitivity.
The invention according to claim 3 is characterized in that the vibration frequency of the drive vibration and the detection vibration is adjusted by changing the width of the support beam for the drive vibration with respect to the width of the support beam for the detection vibration. Furthermore, in the invention according to claim 4, a pair of support beams for detection vibration are disposed at positions symmetrical with respect to the driving vibration direction due to Lorentz force, and the pair of detection beams A support beam for driving vibration is provided. The invention according to claim 5 is
An electromagnetically driven angular velocity sensor is used under atmospheric pressure.

According to such a configuration, when an electric current is applied to the supporting beam for driving vibration, the Lorentz force acts on the weight of the oscillator based on the current flowing through the weight of the oscillator and the magnetic field generated by the magnet. As a result, the vibrator vibrates in a horizontal direction perpendicular to the magnetic field of the magnet. When an angular velocity is applied in the vertical axis direction from this state, the vibrator vibrates in the horizontal direction perpendicular to the angular velocity direction and the driving direction due to the Coriolis force. Therefore,
Due to this vibration, an induced electromotive force is generated in the support beam for the detected vibration, and a voltage based on the induced electromotive force is measured, and an appropriate process is performed based on the voltage to detect the angular velocity. If the width of the support beam for drive vibration and the width of detection vibration are the same, the vibration (detection vibration) generated by the vibration direction and the angular velocity by the electromagnetic drive is in the same vibration mode. , And a complete resonance type. Further, by changing the width of one of the support beams, the vibration frequency changes. Therefore, since the vibration frequency of the drive vibration and the detection vibration match, the sensitivity increases,
In addition, the vibration frequency can be freely adjusted, and the frequency characteristics of the angular velocity sensor can be improved. In addition, since the vibrator is applied with driving vibration by electromagnetic drive, the driving amplitude is increased, the angular velocity is detected with high accuracy, and the vibrator is vacuum-sealed because it is not easily affected by air damping. Is unnecessary, and the cost is reduced.

In a method of manufacturing an electromagnetically driven angular velocity sensor according to the present invention, a thermal oxide film is formed on the front and back surfaces of a silicon substrate and patterning is performed on the rear surface, and the back surface of the silicon substrate is etched using the thermal oxide film as a mask. Forming a gap by removing the thermal oxide film on the back surface of the silicon substrate,
Forming an electrode on the surface of the silicon substrate by sputtering, forming a metal wiring and an electrode portion by patterning; and forming a metal wiring, an electrode portion, a weight corresponding to the vibrator and a support beam on the surface of the silicon substrate. Forming a resist pattern and removing the thermal oxide film on the surface of the silicon substrate by etching; and performing reactive ion etching using the resist pattern as a mask to perform a through etching of the silicon substrate; removing the resist pattern;
The configuration includes a step of anodically bonding the silicon substrate and the glass substrate, and a step of connecting a lead wire to the electrode portion and attaching a permanent magnet to the lower surface of the glass substrate. Preferably, the through etching is inductively coupled plasma reactive ion etching.

With this configuration, in the method of manufacturing an electromagnetically driven angular velocity sensor according to the present invention, only three masks are required for manufacturing the angular velocity sensor, and the manufacturing process is greatly simplified. In addition, since the through etching of the silicon substrate is an etching with extremely good anisotropy, a vibrator can be accurately formed with good structural symmetry, and the weight of the vibrator is larger than that of the entire angular velocity sensor. Can be formed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In an electromagnetically driven angular velocity sensor according to the present invention, for example, a vibrator provided on a glass substrate comprises a plate-shaped weight having a center of symmetry on which electrode wiring is formed, and the weight being symmetrical. And a magnet for applying a uniform magnetic field to a current flowing through the electrode wiring formed as a weight. This magnet may be, for example, a permanent magnet. The weight of the vibrator preferably has a shape having a center of symmetry and a large weight, for example, a rectangular shape or a substantially square shape.

This electromagnetically driven angular velocity sensor has a pair of supporting beams for driving vibration as supporting beams for supporting the weight of the vibrator, and a pair of detecting beams for detecting vibration due to Coriolis force when an angular velocity is applied. A supporting beam for vibration. The supporting beam for driving vibration is disposed at a position symmetric with respect to the detection vibration direction, and the supporting beam for detecting vibration is disposed at a position symmetrical with respect to the driving vibration direction. Furthermore, the wiring formed on the support beam for each drive vibration and each electrode wiring formed at a position symmetrical to the weight are connected to one electric circuit, and the wiring formed on the support beam for each detection vibration is also Similarly, one electric circuit is formed with each electrode wiring formed at a symmetrical position of the weight.

In the electromagnetically driven angular velocity sensor having such a configuration, when an alternating current is applied to the electrode wiring of the weight, the Lorentz force acts in a horizontal plane direction (same plane as the vibrator) perpendicular to the direction of the current due to the magnetic field. The vibrator vibrates. At this time, when an angular velocity is applied vertically above the vibrator, the vibrator vibrates on the same plane in a direction perpendicular to the driving vibration direction by Coriolis force. Due to this vibration, induced electromotive force is generated at both ends of a pair of support beams for detection vibration. Therefore, the applied angular velocity can be determined from the induced voltage. Further, since the driving vibration and the detection vibration are on the same plane, a complete resonance type can be obtained, and the sensitivity is high.

It is preferable that each support beam is paired in order to improve the symmetry. However, even if it is not a pair, each support beam is arranged on one side of the driving vibration direction and the detection vibration direction due to the Coriolis force. May be. Further, when the width of the support beam for one side of the drive vibration and the width of the support beam for one side of the detection vibration are changed, the vibration frequency of the drive vibration and the detection vibration is changed. Therefore, the frequency characteristic of the angular velocity sensor can be improved by changing the width of the support beam, and the angular velocity sensor can be made non-resonant.

Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. In addition, the same code | symbol was used for the substantially same or corresponding thing. FIG. 1 shows an embodiment of an electromagnetically driven angular velocity sensor according to the present invention. In FIG. 1, the angular velocity sensor 10 includes a glass substrate 11, a vibrator 20 provided on the surface of the glass substrate 11, and a permanent magnet 12 attached to the back surface of the glass substrate 11. It has a three-layer structure. FIG. 2 is a front view showing another embodiment of the electromagnetically driven angular velocity sensor according to the present invention. 3A is an end view taken along line BB of FIG. 2, and FIG. 3B is an end view taken along line CC of FIG.

Referring to FIGS. 1 to 3, a region indicated by L2 is a vibrator 20, a gap is formed below the vibrator 20, and a glass substrate 11 and a permanent magnet 12 are provided. In the electromagnetically driven angular velocity sensor 10 shown in FIG. 2, the range of L1 is one unit of the angular velocity sensor. The glass substrate 11 is selected to have a thickness of, for example, 300 μm.
Is composed of, for example, an Sm-Co magnet. Further, the silicon substrate 30 is selected to have, for example, a thickness of 200 μm and a length L1 of each side of about 10 mm. In FIG. 2, 150 is set so as to have a gap of, for example, about 50 μm on the lower surface side.
The vibrator 20 is composed of a vibrator weight 21 formed with a thickness of about μm and a pair (ie, a total of eight) of support beams 22 that support the vibrator weight 21 on each side. Have been. In the illustrated case, the weight 21 of the vibrator has, for example, a substantially square outer shape with a length L2 of each side of about 7 mm, and a pair of the pair at a position inward at an intermediate position between the sides. The support beams 22 are supported in a hollow manner by the support beams 22. Further, the vibrator 20 includes a pair of metal wires 33a and 33b formed on the surface thereof so as to connect the support points of the pair of support beams 22 on each side.

As shown in FIGS. 1 and 2, the support beam 22 has a portion extending perpendicularly to each side from an inner support point and a right angle from the tip of each side of the weight 21 of the vibrator. L
It is formed in the shape of a letter, and its thickness is selected to be about 150 μm like the weight 21 of the vibrator. The tip of each support beam 22 is the weight 21 of the vibrator.
, And is fixed and held by being anodically bonded to the glass substrate 21 there. As a result, the weight 21 of the vibrator is
By 2, it is held hollow on the glass substrate 11. Further, each of the support beams 22 has an electrode portion (described later) formed on the surface of the tip.

Here, the angular velocity sensor 10 is manufactured, for example, as shown in FIG. FIG. 4 is a schematic view of the manufacturing process of the end face along the line AA in FIG. First, in FIG. 4A, a thermal oxide film 31 is formed on the front surface and the back surface by thermally oxidizing a silicon substrate 30 having a predetermined thickness, for example, 200 μm, and then the back surface is patterned. This oxide film serves as a first mask. Next, in FIG. 4 (B), the thermal oxide film 31 is used as a first mask, and 50 μm is etched from the back surface using, for example, TMAH.
Is formed, and the thermal oxide film 31 on the back surface is removed. Thus, the thickness of the silicon substrate 30 corresponding to the gap 32 becomes 150 μm. Subsequently, as shown in FIG. 4C, a metal film is formed on the surface of the silicon substrate 30 by sputtering Au / Cr, and a metal wiring 33 and an electrode portion 33a are formed by patterning. This patterning of the metal film serves as a second mask.

Thereafter, as shown in FIG. 4D, a resist pattern 34 is formed on the surface of the silicon substrate 30 at portions corresponding to the metal wiring 33, the electrode portion 33a, the oscillator weight 21, and the support beam 22. After that, the thermal oxide film 31 is removed using the resist pattern 34 as a third mask. Subsequently, as shown in FIG. 4E, using the resist pattern 34 as a third mask, for example, ICPRIE
The silicon substrate 30 is penetrated by etching 35 by (inductively coupled plasma reactive ion etching), and then the resist pattern 34 is removed. In this penetration etching, it is important to make the etching rate uniform and suppress over-etching. Finally, as shown in FIG.
While connecting the lead wire 36 to the electrode portion 33a,
The silicon substrate 30 and the glass substrate 11 are anodic-bonded, and a permanent magnet 12
Is attached by bonding or the like. Thus, the angular velocity sensor 1
0 will be completed.

According to such a manufacturing method, a vibrator having a large weight can be accurately formed, and three masks are required for forming a gap between the vibrator and the glass substrate, so that the manufacturing process is very simple. become.

Next, the function of the angular velocity sensor 10 of the present invention will be described. FIG. 5 is a schematic diagram showing a measuring circuit for measuring the vibration characteristics of the electromagnetically driven angular velocity sensor shown in FIG. 40 indicates a network analyzer,
Reference numeral 41 denotes an operational amplifier. Referring to FIG. 5, the entire angular velocity sensor 10 of the present invention is attached to an object or the like for measuring an angular velocity, and a pair of supporting beam electrode portions (driving electrodes) 25 corresponding to one side of the vibrator 20. An AC voltage (e.g., 0.3 Vp-p) is applied from the network analyzer 40 to the area 26. Thus, the vibrator 20 acts on the magnetic field of the permanent magnet 12 to be electromagnetically driven, and starts driving vibration. Then, the induced electromotive force generated by this vibration is applied to the opposite electrode portions (drive monitoring electrodes) 27 and 2.
8, amplified by an operational amplifier 41, and returned to the network analyzer 40 to detect vibration by the network analyzer 40. All measurements were performed in the atmosphere.

The vibration characteristics of the angular velocity sensor 10 using such a measuring device, that is, the magnitude (dB) and phase (degree) of the vibration with respect to the frequency are as shown in the graphs of FIGS. According to the vibration characteristics, the resonance frequency of the driving vibration is 548 Hz, and the resonance frequency of the detection vibration is 562H.
z, and their mutual deviation was about 2%. Therefore, since the driving vibration and the detection vibration are in the same vibration mode, the driving vibration and the detection vibration become almost perfect resonance type, so that a detection sensitivity with a high angular velocity can be obtained. This shift is due to the unevenness of the cross-sectional area of each support beam 22 due to the non-uniformity of the etching rate during the through-etching of the silicon substrate 30.

Here, the two resonance peaks, that is, the resonance frequency and the Q value in the detection vibration and the drive vibration change as shown in the graphs of FIGS. 8 and 9 with the change in the degree of vacuum. As a result, the Q of the drive vibration and the detected vibration
Both values did not show a sharp change with respect to the change in the degree of vacuum. This is because the vibrator 20 has a large gap with respect to the surface of the glass substrate 11 and thus is not easily affected by air damping. Therefore, the present angular velocity sensor 10 does not require vacuum sealing of the vibrator 20.

The angular velocity sensor 10 having such vibration characteristics detects the angular velocity as shown in FIG.
As shown in FIG. 10, the whole angular velocity sensor 10 of the present invention is attached to an object for measuring angular velocity,
When a driving voltage is applied between the electrode portions (driving electrodes) 25 and 26 of the pair of support beams corresponding to one side of the pair and a current flows in the x direction, the Lorentz force is generated based on the magnetic field direction z by the permanent magnet 12. Act on the vibrator 21, and drive vibration is generated in the horizontal direction y.

In this state, when an angular velocity is applied in the vertical direction z, the vibrator 20 vibrates (detects vibration) in the horizontal direction x perpendicular to the electric field due to Coriolis force. Thereby, a pair of support beams 22 related to the electrode portions 25 and 26 and an electrode portion (detection electrode) of a pair of support beams 22 on an adjacent side.
An induced electromotive force is generated between 23 and 24. Therefore, by measuring the voltage due to this induced electromotive force,
By performing appropriate processing based on the measured voltage, the angular velocity can be detected.

More specifically, in FIG. 10, the angular velocity sensor 10 and the measurement circuit are set on a turntable (not shown), and the driving electrodes 25 and 26 of the angular velocity sensor 10 are supplied from the driving power source 42 at 12 Vp at 548 Hz. -P and an AC voltage of 20 Vp-p are applied. The driving amplitude of the vibrator 20 at this time is 40 and 70 μm, respectively. When an angular velocity is applied to the vibrator 20 that is driven and vibrated by the electromagnetic drive in this way by the rotation of the turntable, the vibrator 20 starts vibrating in the x direction due to the Coriolis force. The induced electromotive force generated thereby is taken out from the detection electrodes 23 and 24, amplified by, for example, an amplifier 41 having a gain of 500, and synchronously detected by a detection circuit 43 based on a drive signal from a drive power supply 42 to correspond to the angular velocity. Output voltage. This output voltage is shown in FIG.
The angular velocity is detected based on the output voltage. In FIG. 11, a shows the case where the driving voltage is 20 V and the driving amplitude is 70 μm, and b shows the case where the driving voltage is 12 V
Shows the case where the drive amplitude is 40 μm.

In the electromagnetically driven angular velocity sensor according to the present invention, since a voltage is generated at the detection electrodes 23 and 24 by the dielectric electromotive force, the CV conversion differs from, for example, the capacitance detection in the electrostatically driven angular velocity sensor. Is unnecessary, so J
An FET or the like (for CV conversion) is not required, and the configuration is simplified. In the above embodiment, when detecting the angular velocity shown in FIG. 10, only the electrode portions 23 and 24 of the support beam on one side are used as detection electrodes in relation to the two pairs of support beams facing each other. However, if the induced electromotive force is detected by using the electrode portions 23 and 24 and the electrode portions 52 and 54 of both the support beams, the angular velocity detection with almost twice the sensitivity can be performed. Is clear.

[0030]

As is apparent from the above description, according to the electromagnetically driven angular velocity sensor of the present invention, the vibrator does not need to be vibrated between the narrow gaps, and the vibrator has a large weight. This has the effect that the child can be driven with a large amplitude and the sensitivity of the angular velocity sensor can be increased. Further, in the present invention, since the vibration caused by the electromagnetic drive and the vibration (detection vibration) generated by the angular velocity are vibration modes on the same plane, the resonance frequency can be easily adjusted, and a complete resonance type can be achieved. This has the effect that the detection sensitivity of angular velocity can be significantly increased. Further, according to the present invention, the oscillation frequency can be freely determined by changing one of the beam widths to make it non-resonant, and the frequency characteristics of the angular velocity sensor can be improved. Further, in the present invention, since the driving amplitude of the vibrator having a large weight is large, the angular velocity can be detected with high accuracy, and there is an effect that it is not affected by air damping. Therefore, vacuum sealing of the vibrator becomes unnecessary, and the cost is reduced.

In the method of manufacturing an electromagnetically driven angular velocity sensor according to the present invention, a vibrator having a large weight can be formed accurately with good symmetry, and three masks are required for manufacturing the sensor. It has the effect that it can be done very easily. Therefore, manufacturing costs and assembly costs are reduced.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing the configuration of an embodiment of an electromagnetically driven angular velocity sensor according to the present invention.

FIG. 2 is a front view showing another embodiment of the electromagnetically driven angular velocity sensor according to the present invention.

3A is an end view taken along the line BB of FIG. 2, and FIG.
FIG. 5 is an end view taken along line CC of FIG.

FIG. 4 is a process diagram sequentially illustrating a manufacturing process of an end surface of the electromagnetically driven angular velocity sensor of FIG. 2 along the line AA.

FIG. 5 is a schematic diagram showing a measurement circuit for measuring vibration characteristics of the electromagnetically driven angular velocity sensor of FIG. 1;

FIG. 6 is a graph showing vibration characteristics in driving vibration measured by the measurement circuit of FIG. 4;

FIG. 7 is a graph showing a vibration characteristic of the detected vibration measured by the measurement circuit of FIG. 4;

8 is a graph showing a resonance frequency of driving vibration and a Q value with respect to a degree of vacuum in the electromagnetically driven angular velocity sensor of FIG. 1;

FIG. 9 is a graph showing a resonance frequency and a Q value of detected vibration with respect to a degree of vacuum in the electromagnetically driven angular velocity sensor of FIG. 1;

FIG. 10 is a schematic diagram showing a configuration of an angular velocity measuring circuit using the electromagnetically driven angular velocity sensor of FIG. 1;

11 is a graph showing a relationship between an angular velocity and an output voltage by the angular velocity measuring circuit shown in FIG.

12A and 12B show an example of a conventional angular velocity sensor, in which FIG. 12A is a schematic sectional view, and FIG. 12B is a perspective view of a silicon substrate.

FIG. 13 is an exploded perspective view showing another example of the conventional angular velocity sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electromagnetic drive type angular velocity sensor 11 Glass substrate 12 Permanent magnet 20 Vibrator 21 Vibrator weight 21a Metal wiring 22 Support arm 23, 24, 52, 54 Detection electrode 25, 26 Driving electrode 27, 28 Driving monitoring electrode 30 Silicon substrate 31 Thermal oxide film 32 Gap 33 Metal wiring 33a Electrode part 34 Resist pattern 35 Penetration etching 36 Lead wire

Claims (7)

[Claims] An oscillator having a symmetrical weight having electrode wiring formed thereon, and a plurality of support beams for elastically supporting the weight at symmetrical positions, and applying a uniform magnetic field to the weight. A magnet, and a substrate having the vibrator on an upper surface side and a magnet having the magnet on a lower surface side, wherein the one support beam forms an electric circuit formed by the electric wiring formed on the upper surface and the electrode wiring of the weight. The other supporting beam is a supporting beam for detecting vibration in which the electric wiring formed on the upper surface and the electrode wiring of the weight are formed in one electric circuit. The Lorentz force acts on the weight of the vibrator by applying a current to the support beam for driving vibration, and the Lorentz force acts on the weight of the vibrator. Right angle An electromagnetically driven angular velocity sensor for detecting an induced electromotive force generated by vibrating in a direction at both ends of the support beam for detecting vibration to detect an angular velocity. 2. The weight has a substantially square shape, and the width of the support beam for the drive vibration and the width of the support beam for the detection vibration are made the same so that the resonance type has high sensitivity. The electromagnetically driven angular velocity sensor according to claim 1, wherein: 3. The vibration frequency of the drive vibration and the detection vibration is adjusted by changing the width of the support beam for the drive vibration with respect to the width of the support beam for the detection vibration.
The electromagnetically driven angular velocity sensor according to claim 1. 4. A pair of support beams for detecting vibration are disposed at positions symmetrical with respect to a driving vibration direction due to the Lorentz force, and a pair of support beams are disposed at positions symmetrical with respect to the detecting vibration direction due to the Coriolis force. 4. The electromagnetically driven angular velocity sensor according to claim 1, further comprising a support beam for driving vibration. 5. Use at atmospheric pressure,
The electromagnetically driven angular velocity sensor according to claim 1. 6. A step of forming a thermal oxide film on the front and back surfaces of a silicon substrate and patterning the reverse surface, etching the rear surface of the silicon substrate using the thermal oxide film as a mask to form a gap, Removing the thermal oxide film on the back surface of the silicon substrate, forming an electrode on the surface of the silicon substrate by sputtering, and forming a metal wiring and an electrode part by patterning; the metal wiring, the electrode part, the weight of the vibrator, and the support beam Forming a resist pattern on the surface of the silicon substrate at a portion corresponding to the above, and removing the thermal oxide film on the surface of the silicon substrate by etching; and penetrating the silicon substrate by reactive ion etching using the resist pattern as a mask. Etching step, removing the resist pattern, the silicon substrate and the glass substrate A step of anodic bonding, to connect the lead wire to the electrode portion, the manufacturing method of the electromagnetic driven angular velocity sensor comprising the steps of mounting a permanent magnet to the lower surface of the glass substrate. 7. The method according to claim 6, wherein the penetration etching for forming the support beam is inductively coupled plasma reactive ion etching.