JP3329068B2 - Angular velocity sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity sensor for detecting an angular velocity of a rotating body.

[0002]

2. Description of the Related Art FIGS. 10 and 11 show two different types of conventional angular velocity sensors.

First, FIG. 10 shows a general angular velocity sensor according to a first prior art.

In the drawing, reference numeral 1 denotes an angular velocity sensor according to a first prior art, 2 denotes a substantially Y-shaped tuning fork vibrator, and the tuning fork vibrator 2 is a pair of plate-like members extending upward facing each other. Vibration plates 2A and 2B, thick bottom 2C connecting plate-like vibration plates 2A and 2B, and fixed plate 2E supported from bottom 2C via column 2D serving as a tuning fork axis (Z axis). Have been.

Reference numerals 3A and 3B denote driving piezoelectric elements fixed to the outside of the plate-like diaphragms 2A and 2B of the tuning-fork vibrator 2, respectively. The driving piezoelectric elements 3A and 3B are formed of a thin film made of a material such as PZT. Is formed.

Reference numeral 4 denotes a detecting portion protruding from a side surface of the bottom 2C. Vibration displacement detecting means (not shown) formed by magnets or electrodes is provided on both side surfaces of the detecting portion 4. .

For convenience, in the angular velocity sensor 1 described above, the direction in which the detecting portion 4 is protruded is the X axis, and the direction in which the tuning forks of the plate-shaped diaphragms 2A, 2B are vibrated (arrows A1, A2) is Y.
The direction in which the axis and the column 2D extend is the Z axis, and the plate-shaped diaphragms 2A and 2B of the tuning fork vibrator 2 generate vibration in the Y axis direction with the Z axis being the tuning fork axis (center axis). .

In the angular velocity sensor 1 according to the first prior art constructed as described above, when a vibration driving signal is applied to the driving piezoelectric elements 3A and 3B, the plate-like vibration plates 2A and 2B are moved in the directions indicated by arrows A1 and A2. When the tuning fork vibrator 2 is rotated around the Z-axis (tuning fork axis) at an angular velocity ω in this state, the tuning fork vibrators spread in the X-axis directions opposite to each other. Coriolis force (inertial force) is generated. The torque caused by the Coriolis forces F1 and F2 acts on the tuning fork vibrator 2, and the tuning fork vibrator 2 generates torsional vibration.
The magnitude of the torsional vibration is detected by the detection unit 4 to detect the angular velocity ω.

However, since the angular velocity sensor according to the first prior art is manufactured by machining, it has a drawback that it cannot be finely machined and becomes large.

As a solution to this drawback, an angular acceleration sensor according to a second prior art shown in FIG. 11 is also known. Note that this angular velocity sensor is manufactured using a semiconductor substrate such as a silicon substrate and utilizing semiconductor fine processing technology.

In the figure, reference numeral 11 denotes an angular velocity sensor according to a second prior art. The angular velocity sensor 11 comprises a substrate 12 formed of a silicon material having a high resistance,
An angular velocity detecting unit, which will be described later, is formed on the surface 2 by processing a polysilicon material.

Reference numerals 13 and 13 denote support portions, and each of the support portions 1
Numeral 3 is provided on the substrate 12 so as to be spaced apart in the front-rear direction, and each of the support portions 13 is integrally formed with four support beams 14, 14, ... extending in the front-rear direction.

Reference numeral 15 denotes a frame-shaped tuning fork vibrator supported via each support beam 14. The tuning fork vibrator 15 includes a pair of diaphragms 16 and 16 provided apart from each other in the left-right direction. Vibration-side comb-shaped electrodes 17, 17 formed on the left and right side surfaces of each diaphragm 16 and having a plurality of electrode plates 17A, 17A,... Extending in the left-right direction. The eight first arms 18, 18,...
And the four first arms 1 each extending in the same direction.
8 extending in the left-right direction connecting the support beam 8 and the support beam 14.
Arm portions 19 and 19.

Reference numerals 20, 21 and 21 denote fixed electrodes fixed on the substrate 12, and the fixed electrodes 20 are provided between the diaphragms 16 (that is, central portions).
Are provided on both left and right sides of the substrate 12. Also, on the left and right side surfaces of the fixed electrode 20 located at the center,
Fixed side comb electrodes 22 having a plurality of electrode plates 22A, 22A,... Are formed so as to face the vibration side comb electrodes 17 of the respective vibration plates 16. Further, a fixed comb having a plurality of electrode plates 23A, 23A,... Is provided on the inner side surface of each fixed electrode 21 located on both left and right sides so as to face the vibration side comb-shaped electrode 17 of each vibration plate 16. An electrode 23 is formed.

Numerals 24, 24 denote vibration generating units as vibration generating means provided between the left and right diaphragms 16, 16 with the fixed electrode 20 interposed therebetween. The respective vibration generating units 24 are comb-shaped electrodes 17 and 22. It is composed of Then, by applying a vibration drive signal to each of the comb-shaped electrodes 17 and 22, each of the vibration plates 16 is indicated by an arrow A by an electrostatic force between them.
1. Drive in the A2 direction.

On the other hand, reference numerals 25, 25 denote vibration generating sections as vibration generating means provided between the vibration plates 16, 16 and the fixed electrodes 21, 21. Each of the vibration generating sections 25 is a comb-shaped electrode 17 And 23. Then, by applying a vibration drive signal to each of the comb electrodes 17 and 23, each vibration plate 16 is vibrated in the directions of arrows A1 and A2 by the electrostatic force between them.

Further, reference numerals 26, 26,... Denote through-holes penetrating the diaphragm 16 in the vertical direction.

In the angular velocity sensor according to the second prior art configured as described above, each support portion 13 and each support beam 1 are provided.
By forming the tuning fork vibrator 15 and the tuning fork vibrator 15 integrally with each other,
5 is supported on the substrate 12 in a floating state, so that the diaphragm 16 can vibrate in the left-right direction and the up-down direction by the tension of the support beam 14 and the arms 18 and 19.

Next, the operation of detecting the angular velocity ω about the Y axis, which is the tuning fork axis (the center axis at which each diaphragm 16 oscillates in the tuning fork), will be described. The basic operation of detecting using the Coriolis force will be described. Is no different.

First, when a vibration drive signal is applied to each of the vibration generating units 24 and 25, each of the vibration plates 16 is moved to the direction indicated by arrows A1, A1 in the figure.
As shown in FIG. 2, when the vibrations rotate in the opposite directions at the same magnitude and rotate at an angular velocity ω about the Y axis (tuning fork axis) in this state, the Coriolis forces F1 and F
2 (Inertial force) is generated. Also, this Coriolis force F1,
F2 causes torsional vibration in the diaphragm 16 and changes in the amplitude of the torsional vibration are detected by an electrode plate (not shown) serving as a vibration displacement detecting means disposed between the substrate 12 and each of the diaphragms 16 to face each other. This is detected as a change, and this is output as a detection signal of the angular velocity.

In the second prior art, since the semiconductor device can be manufactured using the semiconductor fine processing technology, there is an advantage that the size can be reduced with extremely high processing accuracy compared to the first prior art.

On the other hand, when the angular velocity sensor is manufactured by using a semiconductor (silicon or polysilicon) processing technique, it becomes possible to manufacture an angular velocity sensor having a high Q value at resonance due to the mechanical characteristics of the semiconductor.

[0023]

By the way, in the above-mentioned second prior art, each diaphragm 1 of the tuning fork vibrator 15 is provided.
6 is a first arm 18 extending in the front-rear direction from each corner of each diaphragm 16, and a second arm 19 extending in the left-right direction connected to each first arm 18. And is supported by each support beam 14 (each support portion 13). For this reason, a large distortion is generated between each corner and the first arm 18 due to the torsional vibration caused by the Coriolis forces F1 and F2 generated in each diaphragm 16, and most of the vibration energy causing the torsional vibration is the first.
There is a problem that the light is transmitted to the substrate 12 via the arm 18, the second arm 19, the support beam 14, and the support 13 and leaks out from the substrate 12 and is consumed.

As a result, each diaphragm 16 of the tuning fork vibrator 15
Is low, the torsional vibration of the Coriolis forces F1 and F2 in each diaphragm 16 is reduced, and the detection sensitivity is reduced.

The present invention has been made in view of the above-described problems of the prior art, and the present invention provides a highly sensitive angular velocity detection by setting each diaphragm of a tuning fork vibrator torsionally vibrating to a high resonance state. It is an object of the present invention to provide an angular velocity sensor capable of performing the following.

[0026]

[0027]

[Means for Solving the Problems ] To solve the above-mentioned problems.
For the configuration of the angular velocity sensor in the first aspect of the present invention is employed includes a substrate, a formed support frame on the substrate, the pair of diaphragms to perform a tuning fork vibration and axial center of the tuning fork shaft, A tuning fork vibrator formed in a frame shape smaller than the support frame by an arm portion for holding each of the diaphragms, and a tuning fork shaft for supporting the tuning fork vibrator on the substrate via the support frame. The tuning fork vibrator and the supporting frame are provided to transmit torsion caused by Coriolis force generated in each diaphragm when an angular velocity about the tuning fork axis of the tuning fork vibrator is applied as a rotation axis. And a torsional vibrator for detection formed in a medium frame and connected between the vibrator and vibrating displacement detecting means for detecting the vibrating displacement of the torsional vibrator for detection as an angular velocity around the tuning fork axis. A portion that serves as a node of tuning fork vibration generated from each diaphragm of the tuning fork vibrator The lies in the fixed by the support beams.

Further, organic structure of the angular velocity sensor in the invention of claim 2 is employed, a substrate, a support frame which is formed on the substrate, the pair of diaphragms to perform a tuning fork vibration and axial center of the tuning fork axis A tuning fork vibrator formed in a frame shape smaller than the support frame by an arm portion holding each of the diaphragms; and a tuning fork for supporting the tuning fork vibrator on the substrate via the support frame. In order to transmit the torsion caused by the Coriolis force generated in each diaphragm when the support beam provided on the shaft and the angular velocity about the tuning fork axis of the tuning fork vibrator as a rotation axis are applied, the inside of the tuning fork vibrator is transmitted. And a plate-shaped torsional vibrator for detection, which is connected to the tuning fork shaft, and vibration displacement detecting means for detecting a vibration displacement of the torsional vibrator for detection as an angular velocity about the tuning fork shaft. The part that becomes a node of the tuning fork vibration generated from each diaphragm of the Lies in the fixed lifting beam.

According to the third aspect of the present invention, the substrate can be formed of a single crystal silicon material, and the support frame, the support beam, the tuning fork vibrator, and the torsional vibrator for detection can be formed of a polysilicon material. .

According to the fourth aspect of the present invention, a buffering torsional vibrator can be provided outside the detecting torsional vibrator.

[0031]

[0032]

According to the first aspect of the present invention, the supporting frame is formed into a large frame, the torsional vibrator for detection is formed into a medium size, and the tuning fork vibrator is formed into a small frame. The vibrator, tuning fork vibrator and support beam can be formed on the same plane. In addition, by fixing the node portion, which is the fixed point of the tuning fork vibrator , with the support beam, this node becomes a fixed point of the tuning fork vibration.
Vibration that leaks to the substrate via the support beam and support frame
Energy can be reduced, and each diaphragm can be maintained in a resonance state with a high Q value.

Further, as in the second aspect of the present invention, the support frame is formed in a large frame shape, the tuning fork vibrator is formed in a medium frame shape, and the detecting torsional vibrator is formed in a plate shape located in the tuning fork vibrator. The support frame, the tuning fork vibrator, the torsional vibrator for detection, and the support beam can be formed on the same plane. In addition, by fixing the nodes of the tuning fork vibrator that are fixed points with support beams,
Each diaphragm can be maintained in a resonance state having a high Q value.

On the other hand, as in the invention of claim 3, the polysilicon material layer formed on a substrate of silicon material, by a film of the polysilicon etched like, easily support frame, the tuning fork vibrator and A torsional vibrator for detection can be formed.

Further, as in the invention of claim 4, by providing the buffer for torsional vibrator between the vibrator torsional detection tuning fork vibrator twist is propagated to the outside from the torsional detection vibrator vibrating Can be alleviated by the torsional vibration damper, and the vibration energy leaking to the outside via the support beam and the support frame can be extremely reduced.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiments, the same components as those of the above-described conventional technology are denoted by the same reference numerals, and description thereof will be omitted.

First, FIGS. 1 to 3 show a first embodiment of the present invention.

In the figure, reference numeral 31 denotes an angular velocity sensor according to the present embodiment, and 32 denotes a substrate formed of a single crystal silicon material in a plate shape.

Reference numeral 33 denotes a support frame fixed on the substrate 32 and formed in a large frame shape by a polysilicon material.
The support frame 33 includes support beams 34 and 3 serving as tuning fork axes to be described later.
4 is formed so as to protrude inward in the Y-axis direction as a tuning fork shaft.

Here, each of the support beams 34, 34 includes first support beam portions 35, 35 for connecting a support frame 33 and a torsional vibrator 40 for detection, which will be described later, and the torsional vibrator 40 for detection.
Support beam portions 36, 3 for connecting the
6, each of the second support beams 36 extends in the Y-axis direction toward the center of the support frame 33.
A, 36A, and U-shaped support beams 36B, 36B connected to the respective bar-shaped support beams 36A and formed in a substantially U-shape having tips 36B1, 36B1. Further, each arm 39 of the tuning fork vibrator 37 is connected to each tip 36B1 of each of the U-shaped support beams 36B.

Reference numeral 37 denotes a tuning fork vibrator located on the substrate 32 and formed of a polysilicon material in a small frame shape. The tuning fork vibrator 37 includes a pair of vibrators provided at positions parallel to the Y axis. The tuning fork vibrator 37 is formed into a substantially U-shaped arm portion 39 which is connected to each of the diaphragms 38 and forms the tuning fork vibrator 37 in a frame shape. Further, since the tuning fork vibrator 37 is connected to the support frame 33 via the support beam 34 to each of the arms 39, the tuning fork vibrator 37 is supported in a state of floating on the substrate 32.

In the tuning fork vibrator 37, when the diaphragms 38 vibrate in a tuning fork manner, the portions P serving as nodes of the tuning fork vibration (fixing points of the tuning fork vibration) are present on the arms 39, 39, The U-shaped support beam 3 is located at the position of the node P
By connecting the tip portions 36B1 of 6B, a portion P serving as a node of the tuning fork vibrator 37 is fixed by the support beam.

Numeral 40 designates a torsional vibrator for detection positioned and connected between the support frame 33 and the tuning fork vibrator 37. The torsional vibrator for detection 40 comprises a first support beam 35 and a first torsion vibrator. The tuning fork vibrator 37 is held by the second support beam portion 36 and is formed in a medium frame shape by a polysilicon material.

Reference numeral 41 denotes a fixed electrode. The fixed electrode 41 is fixed at a central portion of the substrate 32.

Reference numerals 42, 42 denote vibration generating units as vibration generating means provided between the left and right vibration plates 38, 38 with the fixed electrode 41 interposed therebetween. 38 and a side surface 41A of the fixed electrode 41. And each side 38A, 4
1A, a vibration drive signal is given to generate an electrostatic force between them, and this electrostatic force generates
Numeral 8 vibrates at the same magnitude in opposite directions as indicated by arrows A1 and A2, and the tuning fork vibrator 37 generates a tuning fork vibration centered on the tuning fork axis (Y axis).

Reference numeral 43 denotes a glass substrate that covers the angular velocity sensor 31. A rectangular concave groove 43A is formed in the center of the glass substrate 43, and is bonded to the support frame 33 by anodic bonding, an adhesive, or the like. I have. The cover may be made of not only the glass substrate 43 but also another insulating material (for example, ceramic, resin, or the like).

Reference numerals 44, 44,... Denote detection electrodes as vibration displacement detecting means. Each of the detection electrodes 44 includes an upper surface of the torsional vibrator 40 for detection and a glass substrate 43 facing this surface.
Is formed in the concave groove 43A by an aluminum thin film or the like. The detection electrode 44 provided on the detection torsional vibrator 40 is formed by depositing an insulating film (not shown) such as silicon oxide.

The substrate 32 is formed of a high-resistance silicon plate, and the support frame 33, the support beams 34, the tuning fork vibrator 37, and the torsional vibrator 40 for detection use a low-resistance polysilicon film by diffusing boron or the like. Is formed by

The angular velocity sensor 31 according to this embodiment is configured as described above. Next, the detection operation will be described.

First, when a vibration drive signal is input to each vibration generator 42, an electrostatic force is generated between the fixed electrode 41 and each vibration plate 38 of the tuning fork vibrator 37, and each vibration of the tuning fork vibrator 37 is generated. The plate 38 oscillates in the opposite direction, such as the directions indicated by arrows A1 and A2, with the tuning fork axis (Y axis) as the center axis. In this state, when a rotational force having an angular velocity ω acts on the tuning fork axis, Coriolis forces F1 and F2 are generated on each diaphragm 38 in a direction perpendicular to the tuning fork axis and the tuning fork vibration direction. Due to the Coriolis forces F1 and F2, torque around the tuning fork axis acts on the torsional vibrator 40 for detection via the second support beam 36, and the torsional vibrator 40 for detection generates torsional vibration.

Then, the change in the amplitude of the torsional vibration of the torsional vibrator 40 for detection is detected as a change in the capacitance by each detection electrode 44, and is derived to the outside as a detection signal corresponding to the angular velocity. .

Also, in the angular velocity sensor 31 according to the present embodiment, focusing on a fixed point (node) having no amplitude which is always present when an object vibrates, a portion P of the tuning fork vibrator 37 which serves as a node of the tuning fork vibration is expressed by: Each of the arms 3 of the tuning fork vibrator 37 is connected to each of the distal ends 36B1 of the U-shaped support beams 36B constituting the support beam 34.
9 is fixed, so that the transmission of the vibration energy due to the tuning fork vibration from the tuning fork vibrator 37 to the outside via the support beam 34 that supports the tuning fork vibrator 37 can be reduced. Then, each diaphragm 38 is largely displaced in the directions indicated by arrows A1 and A2, and a resonance state having a high Q value can be obtained.

As a result, the Coriolis forces F1 and F2 with respect to the angular velocity ω applied around the tuning fork axis (Y axis) can be increased, the torsional vibration of the torsional vibrator 40 for detection is increased, and the detection sensitivity of the angular velocity sensor 31 is increased. Can be significantly improved.

Further, by fixing a portion P, which serves as a node in the tuning fork vibration of the tuning fork vibrator 37, to each tip end 36B1 of the U-shaped support beam portion 36B constituting the support beam 34,
It is possible to prevent the tip portions 36B1 and the like from vibrating due to vibration energy, substantially eliminate the vibration of the support beams 34 and the like, improve the durability of each connection portion of the support beams 34 and the like, and improve the angular velocity sensor. The life of the sensor 31 can be reliably extended.

On the other hand, the angular velocity sensor 31 in the present embodiment
Then, the substrate 32 is formed of a silicon plate,
3. Each of the support beams 34, the tuning fork vibrator 37 and the torsional vibrator 40 for detection are integrally formed as a thin film from a polysilicon material on the same plane. Therefore, when the angular velocity sensor 31 is manufactured, a polysilicon film is formed on the entire surface of the substrate 32, and the support frame 33 and the support beams 3 are formed on the polysilicon film.
4. Pattern the tuning fork vibrator 37 and the torsional vibrator 40 for detection. Thus, the small-sized angular velocity sensor 31 can be easily manufactured, and a large number of pieces can be obtained in a state of a silicon wafer. Therefore, the productivity of the angular velocity sensor 31 can be improved.

Next, FIGS. 4 to 6 show a second embodiment according to the present invention.
This embodiment is characterized in that the detecting torsional vibrator is formed in a single plate located at the center of the angular velocity sensor. Note that, in this embodiment, the first
The same reference numerals are given to the same components as those of the embodiment, and the description thereof will be omitted.

In the drawing, reference numeral 51 denotes an angular velocity sensor according to the present embodiment, and 52 denotes a plate formed of a single crystal silicon material in a plate shape.

Reference numeral 53 denotes a support frame fixed on the substrate 52 and formed in a large frame shape by a polysilicon material.
On the support frame 53, support beams 54, 54 extending inward in the Y-axis direction serving as a tuning fork shaft are formed so as to protrude.

Here, the support beams 54, 54 are rod-shaped support beams 55, 55 extending inward in the Y-axis direction to connect the support frame 53 and a tuning fork vibrator 57 described later;
The end portions 56A, 56
A, a substantially U-shaped support beam 56 having a U-shape,
56. Further, an arm portion 59 of a tuning fork vibrator 57 is connected to each end portion 56A of each of the U-shaped support beam portions 56.

Reference numeral 57 denotes a tuning fork vibrator which is located on the substrate 52 and is formed of a polysilicon material in a medium frame shape. The tuning fork vibrator 57 is provided in a pair so as to be parallel to the Y axis. And the substantially U-shaped arms 59, 59 connected to the respective diaphragms 58 to form the tuning fork vibrator 57 in a frame shape. In addition, since the tuning fork vibrator 57 has the arms 59 connected to the support frame 53 via the support beams 54, the tuning fork vibrator 57 is supported in a state of floating on the substrate 52.

In the tuning fork vibrator 57, when each of the diaphragms 58 vibrates in a tuning fork manner, a portion P serving as a node of the tuning fork vibration (a fixed point of the tuning fork vibration) exists on the arm portions 59, 59. The node portion P corresponds to each of the distal ends 56A of the U-shaped support beams 56.

The reference numerals 60, 60 are formed on the outer side surface of the diaphragm 58, and include a plurality of (for example, four) electrode plates 60A, 60A.
The vibrating comb electrodes 60A,... Are arranged so as to face the respective electrode plates 63A of the fixed comb electrodes 63 described later.

Reference numeral 61 denotes a plate-shaped torsional vibrator connected to each arm 59 of the tuning fork vibrator 57 and positioned at the center of the angular velocity sensor 51. The torsional vibrator 61 for detection is
A detecting diaphragm 61A to which a vibration displacement from the tuning fork vibrator 57 is transmitted; bar-shaped bar-shaped arms 61B, 61B extending in the Y-axis direction to hold the detecting diaphragm 61A;
A substantially U-shape is formed on the tip side of each of the rod-shaped arm portions 61B, and the connection portion at the tip is formed by a tip portion 56A,
U-shaped arms 61C, 61C connected to the tuning fork vibrator 57 at positions corresponding to 56A.

Reference numerals 62, 62 denote fixed electrodes which are fixed to the left and right sides of the substrate 52. Each of the fixed electrodes 62 has a plurality of protruding (protruding) faces toward the respective diaphragms 58 located inside. The fixed side comb-shaped electrodes 63, 63 having four (for example, four) electrode plates 63A, 63A,... Are formed.
Here, when a vibration drive signal is input between the comb-shaped electrodes 60 and 63, an electrostatic force is generated between the fixed electrode 62 and each of the vibration plates 58, and each of the vibration plates 58 is caused by this electrostatic force. As shown by arrows A1 and A2, they vibrate in the opposite directions at the same magnitude, and the tuning fork vibrator 57 generates a tuning fork vibration centered on the tuning fork axis (Y axis).

Numerals 64, 64 denote vibration generating units as vibration generating means provided between the diaphragms 58, 58 and the fixed electrodes 62, 62. Each of the vibration generating units 64 is a comb-shaped electrode 60.
And 63. And each comb-shaped electrode 6
By giving a vibration drive signal to 0 and 63, each diaphragm 58 is indicated by arrows A1, A2 by electrostatic force between them.
Vibrating in the direction.

Reference numeral 65 denotes a glass substrate as a cover joined to the support frame 53, and a rectangular groove 65A is formed in the center of the glass substrate 65.

Reference numerals 66, 66 denote detection electrodes as vibration displacement detecting means. Each of the detection electrodes 66 is provided between the upper surface of the torsional vibrator 61 for detection and the concave groove 65A of the glass substrate 65 opposed to this surface. Is formed with a thin film of aluminum or the like. The detection electrode 66 provided on the detection torsional vibrator 61 is an insulating film (not shown) such as silicon oxide.
A film is formed through the film.

In the angular velocity sensor 51 according to the present embodiment having the above-described configuration, the detection operation is the same as that of the angular velocity sensor 31 according to the first embodiment.

The angular velocity sensor 51 according to the present embodiment
In the above, the portion P of the tuning fork vibrator 57 which is a node having no amplitude of the tuning fork vibration is fixed at each end 56A of the U-shaped support beam portion 56, so that the vibration caused by the tuning fork vibration from the tuning fork vibrator 57. Energy is prevented from being transmitted to the outside via the support beam 54 that supports the tuning fork vibrator 57.

As a result, each diaphragm 58 is indicated by arrows A1, A
A large displacement in two directions can be maintained in a resonance state with a high Q value. As a result, the Coriolis forces F1 and F2 with respect to the angular velocity ω applied around the tuning fork axis (Y axis) can be increased, and the detection sensitivity of the angular velocity sensor 51 can be significantly improved.

Each tip 56 of the U-shaped support beam 56
A is a node position P in the tuning fork vibration of the tuning fork vibrator 57.
By connecting with each other, the respective end portions 56A can be prevented from vibrating due to the vibration energy, and the vibration of the support beams 54 and the like can be substantially eliminated, and the durability of each connecting portion can be reliably improved. The life of the angular velocity sensor 51 can be effectively extended.

Further, in this embodiment, each of the vibrating plates 58 of the tuning fork vibrator 57 is formed by the vibration-side comb-shaped electrode 60 and the fixed electrode 6 opposed to the vibration-side comb-shaped electrode 60.
Since 2 is also formed by the fixed-side comb-shaped electrode 63, the effective area between each electrode plate 60A of the vibration-side comb-shaped electrode 60 and each electrode plate 63A of the fixed-side comb-shaped electrode 63 can be increased. Then, the electrostatic force when a vibration drive signal is applied between the electrode plates 60A and 63A can be increased, the vibrations of the diaphragms 58 in the directions indicated by arrows A1 and A2 can be increased, and the detection sensitivity of the angular velocity sensor 51 can be increased. Can be further increased.

FIGS. 7 to 9 show a third embodiment according to the present invention. The features of this embodiment are that the support frame 33 and the torsional vibrator 40 for the angular velocity sensor 31 according to the first embodiment are different from each other. And a torsional vibrator for shock absorption is formed between them. In this embodiment, the same components as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the figure, reference numeral 71 denotes an angular velocity sensor according to the present embodiment; 72, a substrate formed of a single crystal silicon material in a plate shape; 73, a large frame-shaped polysilicon material fixed on the substrate 72; The supporting frame formed by each is shown.

Reference numerals 74, 74 denote support beams projecting inward from the support frame 73 in the Y-axis direction, which is the tuning fork axis. The support beams 74, 74 are connected to the support frame 73 and a torsional vibration for buffering described later. First support beam portions 75, 75 for connecting the child 82
And the torsional vibrator 82 for shock absorption and the torsional vibrator 81 for detection.
, And third support beam portions 77, 77 connecting the detection torsional vibrator 81 and the tuning fork vibrator 78. Each of the third support beam portions 77 includes bar-shaped support beam portions 77A, 77A extending inward from the support frame 73 in the Y-axis direction, and the bar-shaped support beam portions 7A.
A substantially U-shaped support beam portion 77B, 77B having a tip portion 77B1, 77B1 is connected to the tip of 7A, and a tuning fork vibration is applied to each tip portion 77B1 of each of the U-shaped support beam portions 77B. The arm 80 of the child 78 is connected.

Reference numeral 78 denotes a tuning fork vibrator located on the substrate 72 and formed of a polysilicon material in a small frame shape. The tuning fork vibrator 78 includes a pair of vibrating plates 79 provided in parallel with the Y axis. , 79, and substantially U-shaped arms 80, 80 connected to the diaphragms 79 to form the tuning fork vibrator 78 in a small frame shape. Further, since the tuning fork vibrator 78 is connected to the support frame 73 via the support beam 74 to each arm portion 80, the tuning fork vibrator 78 is supported in a state of floating on the substrate 72.

In the tuning fork vibrator 78, when each of the diaphragms 79 vibrates in a tuning fork manner, a portion P serving as a node of the tuning fork vibration (a fixed point of the tuning fork vibration) exists on the arms 80, 80. The U-shaped support beam 77B is located at the position of the node P
Are fixed to the tuning fork vibrator 78.

A detecting torsional vibrator 81 is located between the buffering torsional vibrator 82 and the tuning fork vibrator 78 and held by each of the second support beams 76 and each of the third support beams 77. The torsional vibrator 81 for detection is formed in a medium frame shape by a polysilicon material, and transmits the torsional vibration caused by the Coriolis force generated from each diaphragm 79 of the tuning fork vibrator 78.

Reference numeral 82 denotes a support frame 73 and a torsional vibrator 81 for detection.
Between the first and second support beam portions 75 and the second support beam portions 76. The torsional vibrator for shock absorption 82 includes the torsional vibration for detection. Child 8
1, and absorbs vibration energy leaking from the torsional vibrator 81 for detection.

Reference numeral 83 denotes a fixed electrode. The fixed electrode 83 is fixed at the center of the substrate 72.

Numerals 84 and 84 denote vibration generating units as vibration generating means provided between the vibration plates 79 and 79 and the fixed electrode 83. Each of the vibration generating units 84 is a side surface 79 of the vibration plate 79.
A and the side surfaces 83A, 83A of the fixed electrode 83. By applying a vibration drive signal to each of the side surfaces 79A and 83A, an electrostatic force is generated between the diaphragms A1 and A by the electrostatic force therebetween, and the respective vibrations are generated by the electrostatic force. The plate 79 vibrates with the same magnitude in the opposite directions as indicated by arrows A1 and A2, and the tuning fork vibrator 37 generates a tuning fork vibration centered on the tuning fork axis (Y axis).

Reference numeral 85 denotes a glass substrate which covers the angular velocity sensor 71, and a rectangular concave groove 85A is formed in the center of the glass substrate 85. The cover may be made of not only the glass substrate 85 but also another insulating material (for example, ceramic, resin, or the like).

Reference numerals 86, 86,... Denote detection electrodes as vibration displacement detecting means. Each of the detection electrodes 86 is composed of an upper surface of the torsional vibrator 81 for detection and a glass substrate 85 facing this surface.
Is formed by a thin aluminum film or the like in the concave groove 85A. Note that the detection electrode 86 provided on the detection torsional vibrator 81 is formed by deposition via an insulating film (not shown) such as silicon oxide.

In the angular velocity sensor 71 according to the present embodiment having the above-described configuration, the detection operation is the same as that of the angular velocity sensor 31 according to the above-described first embodiment, and a description thereof will be omitted.

However, also in the angular velocity sensor 71 of the present embodiment, since the portion P serving as a node due to the tuning fork vibration of the tuning fork vibrator 78 is fixed by the third support beam 77, the torsional vibration is reduced by the support beam 74. And the loss due to the tuning fork vibration of each diaphragm 79 of the tuning fork vibrator 78 can be increased, and the detection sensitivity of the angular velocity sensor 71 can be improved. Can be done.

However, as described above, the tuning fork vibrator 78
Even if the portion P serving as a node is fixed by the support beam 74, leakage of vibration energy due to a slight displacement cannot be prevented, and therefore, the angular velocity sensor 31 according to the first and second embodiments can be prevented. , 51, small vibration energy is lost. Therefore, as in the case of the angular velocity sensor 71 of the present embodiment, the provision of the buffering torsional vibrator 82 between the support frame 73 and the detecting torsional vibrator 81 reduces the minute vibration energy and transmits it to the outside. be able to. As a result, the torsional vibration of the detected torsional vibrator 81 also increases, and the detection sensitivity of the angular velocity sensor 71 can be further improved.

In the third embodiment, the case where the buffer torsional vibrator 82 is provided solely outside the detecting torsional vibrator 81 has been described. However, the present invention is not limited to this.
, Triple,...

In each of the above embodiments, the tuning fork vibrator 3
Electrostatic force was used to generate tuning fork vibrations on each of the vibrating plates 38, 58, 79 of 7, 57, 78. However, the present invention is not limited to this, and a piezoelectric body or the like according to the first prior art is used. Tuning fork vibration may be generated.

In each of the above embodiments, the tuning fork vibrator 3
Although the case where the portion P serving as a node of the tuning fork vibration generated at 7, 57, 78 is singular has been described, the present invention is directed to the case where there are a plurality of portions P serving as support beams, What is necessary is just to form and fix a support beam so that it may be fixed.

[0090] Furthermore, the tuning fork vibrator 3 in Examples
7, 57, 78 and the torsional vibrators 40, 61, 81 for detection.
, The detection sensitivity can be further improved.

[0091]

[0092]

As described above in detail, according to the first aspect of the present invention, the support frame, the torsional vibrator for detection, and the tuning fork vibrator are each formed in a frame shape, and the members are connected by the support beams. The support frame, the torsional vibrator for detection, the tuning fork vibrator, and the support beam can be formed on the same plane, and the manufacturing can be facilitated. In addition, by fixing the tuning fork vibrator at a portion that becomes a node of the tuning fork vibration via a support beam , torsional vibration from the tuning fork vibrator is prevented.
Vibration energy is transmitted to the outside via the support beam and support frame.
Leakage is reduced, and the Q value of each diaphragm of the tuning fork vibrator is high.
The resonance can be maintained, and the vibration of each diaphragm can be increased to greatly improve the detection sensitivity of the angular velocity in the tuning fork axis direction.

Further, according to the second aspect of the present invention, the support frame and the tuning fork vibrator are each formed in a frame shape, the torsional vibrator for detection is formed in a plate shape, and each member is connected by a support beam. The support frame, the torsional vibrator for detection, the tuning fork vibrator, and the support beam can be formed on the same plane, and the manufacturing can be facilitated.
Further, by fixing the tuning fork vibrator at a portion serving as a node of the tuning fork vibration via the supporting beam, the vibration of each diaphragm is increased, and the detection sensitivity of the angular velocity in the tuning fork axis direction can be greatly improved.

On the other hand, according to the third aspect of the present invention, the substrate is formed of a single crystal silicon material, and the support frame, the support beam, the tuning fork vibrator, and the torsional vibrator for detection are formed of a polysilicon material. If a silicon material is formed into a thin film on a substrate, and the thin film is patterned by etching or the like, a support frame, a support beam, a tuning fork vibrator, and a torsional vibrator for detection can be easily formed, and the productivity of the angular velocity sensor can be significantly improved. .

On the other hand, in the invention of claim 4, since the torsional vibration damper is provided outside the torsional vibrator for detection, the torsional vibration leaking from the torsional vibrator for detection can be reduced, and the torsional vibration to be detected can be reduced. The reduction of torsional vibration in the child is suppressed, and the detection sensitivity is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an angular velocity sensor according to a first embodiment of the present invention with a cover partially cut away.

FIG. 2 is a longitudinal sectional view as seen from the direction of arrows II-II in FIG.

FIG. 3 is a top view of the angular velocity sensor in FIG. 1 as viewed from above.

FIG. 4 is a perspective view showing an angular velocity sensor according to a second embodiment of the present invention with a part of a cover cut away.

FIG. 5 is a vertical cross-sectional view as viewed from a direction indicated by arrows VV in FIG. 4;

6 is a top view of the angular velocity sensor in FIG. 4 as viewed from above.

FIG. 7 is a perspective view showing an angular velocity sensor according to a third embodiment of the present invention with a part of a cover cut away.

8 is a longitudinal sectional view as seen from the direction of arrows VIII-VIII in FIG. 7;

9 is a top view of the angular velocity sensor in FIG. 7 as viewed from above.

FIG. 10 is a perspective view showing an angular velocity sensor according to a first prior art.

FIG. 11 is a perspective view showing an angular velocity sensor according to a second prior art.

[Explanation of symbols]

 31, 51, 71 Angular velocity sensor 32, 52, 72 Substrate 33, 53, 73 Support frame 34, 54, 74 Support beam 37, 57, 78 Tuning fork vibrator 38, 58, 79 Vibrating plate 39, 59, 80 Arm 40 , 61, 81 Torsional vibrator for detection 44, 66, 86 Electrode for detection (vibration displacement detecting means) 82 Torsional vibrator for buffer P Part to be a node

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Katsuhiko Tanaka 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto, Japan Murata Manufacturing Co., Ltd. Examiner Hideo Ariya (56) References A) JP-A-60-140114 (JP, A) JP-A-51-33491 (JP, A) JP-A-63-172915 (JP, A) JP-A-60-73414 (JP, A) Patent 3123301 (JP) , B2) International Publication 93/5401 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01C 19/56 G01P 9/04

Claims (4)

(57) [Claims] 1. A substrate, a support frame formed on the substrate, and a pair of diaphragms for performing tuning fork vibration about a tuning fork shaft as an axis, and the supporting portions are supported by arms for holding the respective diaphragms. A tuning fork vibrator formed in a frame shape smaller than a frame, a support beam provided on a tuning fork shaft for supporting the tuning fork vibrator on the substrate via the support frame, and the tuning fork vibrator A medium-sized medium-positioned and connected between the tuning fork vibrator and the support frame to transmit the torsion caused by the Coriolis force generated in each diaphragm when an angular velocity about the tuning fork shaft as a rotation axis is applied. A torsional vibrator for detection formed in a simple frame shape, and vibration displacement detecting means for detecting a vibration displacement of the torsional vibrator for detection as an angular velocity about a tuning fork axis, which is generated from each diaphragm of the tuning fork vibrator. An angular velocity sensor in which a portion serving as a node of the tuning fork vibration is fixed by the support beam. 2. A substrate, a support frame formed on the substrate, and a pair of diaphragms for performing a tuning fork vibration about a tuning fork shaft as an axis, wherein the arms supporting the respective diaphragms support the diaphragm. A tuning fork vibrator formed in a frame shape smaller than a frame, a support beam provided on a tuning fork shaft for supporting the tuning fork vibrator on the substrate via the support frame, and the tuning fork vibrator In order to transmit the torsion caused by the Coriolis force generated in each diaphragm when an angular velocity about the tuning fork shaft is applied to the center of the rotating shaft, a plate-shaped member positioned inside the tuning fork vibrator and connected to the tuning fork shaft is transmitted. A torsional vibrator for detection, and a vibration displacement detecting means for detecting a vibration displacement of the torsional vibrator for detection as an angular velocity about a tuning fork axis; a portion serving as a node of tuning fork vibration generated from each diaphragm of the tuning fork vibrator Is fixed by the support beam. 3. A formed by silicon material of the substrate single crystal, the support frame, the support beams, the tuning fork oscillator and torsional detection vibrator made by forming a polysilicon material according to claim 1 or 2, wherein Angular velocity sensor. 4. outside the vibrator torsional for the detection, the angular velocity sensor according to claim 1 or 2, wherein formed by providing a buffer for torsional vibrator.