JPH07294262A - Angular speed sensor - Google Patents

Abstract

PURPOSE:To enhance sensitivity in detection by securing a beam for supporting a tuning fork oscillator at the nodes of tuning fork oscillation thereby amplifying the tuning fork oscillation. CONSTITUTION:A supporting frame 33 supports a frame-like torsional oscillator 40 for detection through a supporting beam part 35. The oscillator 40 supports a frame-like tuning fork oscillator 37 through a second supporting beam part 36. In this regard, the tuning fork oscillator 37 is secured, at a node part P thereof, to the forward end part 36B1 of a C-shaped supporting beam part 36B constituting a second supporting beam part 36. This structure reduces the leakage of oscillation energy due to torsional oscillation when the sensor is subjected to an angular speed omega about the axis of tuning fork(Y-axis) and sustains each diaphragm 38 of the oscillator 37 in high oscillatory state thus enhancing sensitivity in the detection of angular speed omega.

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 the angular velocity of a rotating body.

[0002]

2. Description of the Related Art Here, two different types of conventional angular velocity sensors will be shown and described with reference to FIGS.

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

In the figure, 1 is an angular velocity sensor according to the first prior art, 2 is a substantially Y-shaped tuning fork type vibrator, and the tuning fork type vibrator 2 is a pair of plate-shaped members facing each other and extending upward. A diaphragm 2A, 2B, a thick bottom portion 2C connecting the plate-shaped diaphragms 2A, 2B, and a fixed plate 2E supported from the bottom portion 2C via a pillar 2D serving as a tuning fork axis (Z axis). Has been done.

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

Reference numeral 4 denotes a detecting portion provided on the side surface of the bottom portion 2C, and both sides of the detecting portion 4 are provided with vibration displacement detecting means (not shown) formed by magnets or electrodes. .

For the sake of convenience, in the above-described angular velocity sensor 1, the direction in which the detecting portion 4 is provided is the X axis and the direction in which the vibrating plates 2A and 2B vibrate (arrows A1 and A2) is Y.
The Z-axis is the extending direction of the shaft and the column 2D, and the plate-like diaphragms 2A and 2B of the tuning fork type vibrator 2 are adapted to generate vibration in the Y-axis direction with the Z-axis as the tuning fork axis (central 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, 3B, the plate-shaped diaphragms 2A, 2B are directed in the directions of arrows A1, 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 vibrates so as to spread in the same magnitude and period, and F1 and F2 are given in the opposite X axis directions. Coriolis force (inertial force) is generated. The torque generated by the Coriolis forces F1 and F2 acts on the tuning fork vibrator 2, and the tuning fork vibrator 2 causes torsional vibration.
The angular velocity ω is detected by detecting the magnitude of this torsional vibration by the detection unit 4.

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

As a solution to this drawback, an angular acceleration sensor according to the second prior art shown in FIG. 11 is also known. The angular velocity sensor is manufactured by using a semiconductor fine processing technique by using a semiconductor substrate such as a silicon substrate.

In the figure, reference numeral 11 denotes an angular velocity sensor according to a second conventional technique. The angular velocity sensor 11 includes a substrate 12 made of a silicon material having high resistance, and the substrate 1.
An angular velocity detecting portion, which will be described later, is formed on 2 by processing a polysilicon material.

Reference numerals 13 and 13 denote support portions, and the respective support portions 1
3 are provided on the substrate 12 so as to be separated from each other in the front-rear direction, and four support beams 14, 14, ... That extend in the front-rear direction are integrally formed on each of the support portions 13.

Reference numeral 15 denotes a frame-shaped tuning fork vibrator supported through each support beam 14, and the tuning fork vibrator 15 includes a pair of vibrating plates 16 and 16 which are spaced apart from each other in the left-right direction. Vibrating-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, ... Eight first arm portions 18, 18, ...
And each of the four first arm portions 1 extending in the same direction.
8 extending in the left-right direction connecting 8 and the support beam 14
The arm portions 19 and 19 of the.

Reference numerals 20, 21 and 21 denote fixed electrodes fixed on the substrate 12. The fixed electrodes 20 are provided between the vibrating plates 16 (that is, in the center), and the fixed electrodes 21 are provided.
Are provided on both left and right sides of the substrate 12. Further, on the left and right side surfaces of the fixed electrode 20 located in the central portion,
Fixed-side comb-shaped electrodes 22, 22 having a plurality of electrode plates 22A, 22A, ... Are formed so as to face the vibrating-side comb-shaped electrodes 17 of each diaphragm 16. Further, fixed side combs having a plurality of electrode plates 23A, 23A, ... On the inner side surfaces of the fixed electrodes 21 located on both the left and right sides so as to face the vibrating side comb-shaped electrodes 17 of the respective vibrating plates 16. The electrode 23 is formed.

Reference numerals 24 and 24 denote vibration generating portions as vibration generating means provided between the left and right vibrating plates 16 and 16 with the fixed electrode 20 interposed therebetween, and each of the vibration generating portions 24 is comb-shaped electrodes 17 and 22. It consists of and. Then, by applying a vibration drive signal to each of the comb-shaped electrodes 17 and 22, each vibration plate 16 is indicated by an arrow A by the electrostatic force between them.
Drive in the 1 and A2 directions.

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

Further, reference numerals 26, 26, ... Depict through holes penetrating each diaphragm 16 in the vertical direction.

In the angular velocity sensor according to the second prior art constructed as described above, each support portion 13 and each support beam 1
The support beam 14 and the tuning fork vibrator 1 are formed by integrally forming 4 and the tuning fork vibrator 15 with polysilicon.
Since 5 is supported in a floating state on the substrate 12, each diaphragm 16 can be vibrated in the left and right direction and the up and down direction by the tension of the support beam 14 and the arm portions 18 and 19.

Next, the detection operation of the angular velocity ω around the Y axis, which is the tuning fork axis (the central axis where each vibrating plate 16 vibrates in the tuning fork), will be described. In the basic operation of detecting by utilizing the Coriolis force. Does not change.

First, when a vibration drive signal is applied to each of the vibration generators 24 and 25, each diaphragm 16 is moved by the arrows A1 and A in the figure.
As shown in Fig. 2, when they vibrate in the opposite directions with the same magnitude and rotate in this state at the angular velocity ω about the Y axis (tuning fork axis), the Coriolis forces F1 and F
2 (Inertial force) is generated. Also, this Coriolis force F1,
Torsional vibration is generated in the vibrating plate 16 due to F2, and the change in the amplitude of the torsional vibration is detected by an electrode plate (not shown) as a vibration displacement detecting means which is disposed between the substrate 12 and each vibrating plate 16 so as to be The change is detected, and this is output as an angular velocity detection signal.

Since the second conventional technique can be manufactured by using the semiconductor fine processing technique, it has an advantage that it can be miniaturized with extremely high processing precision as compared with the first conventional technique.

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 described.
Reference numeral 6 denotes first arm portions 18 extending in the front-rear direction from the respective corner portions of the diaphragms 16, and second arm portions 19 extending in the left-right direction connected to the first arm portions 18. It is supported by each support beam 14 (each support portion 13) via and. Therefore, torsional vibrations caused by the Coriolis forces F1 and F2 generated in each diaphragm 16 cause a large strain between each corner and the first arm 18, and most of the vibration energy causing the torsional vibration is the first.
There is a problem that it is externally propagated to the substrate 12 through the arm portion 18, the second arm portion 19, the support beam 14 and the support portion 13, and leaks to the outside from the substrate 12 and is consumed.

As a result, each diaphragm 16 of the tuning fork vibrator 15
Has a problem in that the Q value becomes low, the torsional vibrations of the Coriolis forces F1 and F2 in the respective diaphragms 16 become small, and the detection sensitivity decreases.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention is to detect the angular velocity with high sensitivity by setting the respective vibration plates of the tuning fork vibrator that are torsionally vibrated to a high resonance state. It is an object of the present invention to provide an angular velocity sensor capable of performing the above.

[0026]

In order to solve the above-mentioned problems, the structure of the angular velocity sensor adopted by the invention of claim 1 is such that a substrate, a support frame formed on the substrate, and a tuning fork shaft are provided. A tuning fork vibrator having a pair of vibrating plates that vibrate in the center of the tuning fork; and a support beam provided on the tuning fork shaft for supporting the tuning fork vibrator on the substrate via the support frame,
A torsion oscillator for detection connected to the tuning fork oscillator, in order to transmit a twist due to the Coriolis force generated in each diaphragm when an angular velocity about the tuning fork shaft of the tuning fork oscillator is applied, A vibration displacement detecting means for detecting the vibration displacement of the detecting torsional vibrator as an angular velocity around the tuning fork axis, and a portion serving as a node of the tuning fork vibration generated from each diaphragm of the tuning fork vibrator is fixed by the support beam. Especially.

Further, the structure of the angular velocity sensor adopted in the invention of claim 2 has a substrate, a support frame formed on the substrate, and a pair of vibrating plates for vibrating the tuning fork centering on the tuning fork shaft. A tuning fork vibrator formed in a frame shape smaller than the support frame by an arm portion holding each of the vibrating plates, and a tuning fork for supporting the tuning fork vibrator on the substrate via the support frame. A support beam provided on the shaft and the tuning fork vibrator to transmit the twist due to the Coriolis force generated in each diaphragm when an angular velocity about the tuning fork shaft of the tuning fork vibrator is applied as a rotation axis. A torsional vibrator for detection, which is formed in the shape of a medium frame and is connected between the supporting frame and the frame, and a vibrational displacement detection means for detecting the vibrational displacement of the torsional vibrator for detection as an angular velocity around the tuning fork axis. And a tuning fork vibration generated from each diaphragm of the tuning fork vibrator. A portion to be that there be fixed with the support beam.

Further, the structure of the angular velocity sensor adopted in the invention of claim 3 includes a substrate, a support frame formed on the substrate, and a pair of vibrating plates for vibrating the tuning fork centering on the tuning fork shaft. A tuning fork vibrator formed in a frame shape smaller than the support frame by an arm portion holding each of the vibrating plates, and a tuning fork for supporting the tuning fork vibrator on the substrate via the support frame. In order to transmit the twist due to the Coriolis force generated in each diaphragm when a supporting beam provided on the shaft and an angular velocity about the tuning fork shaft of the tuning fork vibrator as a rotation axis are applied, the inside of the tuning fork vibrator is transmitted. The tuning fork vibration is provided with a plate-shaped detection torsional vibrator located on the tuning fork shaft and connected to the tuning fork shaft, and vibration displacement detection means for detecting the vibrational displacement of the detection torsional vibrator as an angular velocity around the tuning fork axis. The part that becomes the node of the tuning fork vibration generated from each diaphragm of the child Some that were fixed in the support beam.

On the other hand, in the invention of claim 4, 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 fifth aspect of the present invention, a buffer torsion oscillator can be provided outside the detection torsion oscillator.

[0031]

According to the present invention, the tuning fork vibrator is supported by the support frame through the support beam, and the portion of the tuning fork vibrator supported by the support beam is generated from each diaphragm of the tuning fork vibrator. Since this is the same as the tuning fork vibration node, this node becomes a fixed point of the tuning fork vibration, and it is possible to reduce the vibration energy leaking to the substrate through the supporting beam and the supporting frame, and to make each diaphragm resonate with a high Q value. Can be held in a state.

According to the second aspect of the present invention, by forming the support frame in a large size, the detection torsional vibrator in a medium size, and the tuning fork vibrator in a small size, the support frame and the detection frame are formed. The torsional oscillator, the tuning fork oscillator and the support beam can be formed on the same plane. Further, by fixing the node portion, which is the fixed point of the tuning fork vibrator, with the support beam, each diaphragm can be held in a resonance state where the Q value is high.

Further, as in the invention of claim 3, the support frame is formed in a large size, the tuning fork vibrator is formed in a medium frame shape, and the detection torsional vibrator is formed in a plate shape located in the tuning fork vibrator. The support frame, the tuning fork vibrator, the detection torsion vibrator, and the support beam can be formed on the same plane. In addition, by fixing the node part, which is the fixed point of the tuning fork vibrator, with the support beam,
Each diaphragm can be kept in a resonance state with a high Q value.

On the other hand, as in the invention of claim 4, by forming a film of a polysilicon material on a substrate made of a silicon material and etching the film of the polysilicon, the supporting frame, the tuning fork vibrator and the tuning fork vibrator are easily formed. A torsion oscillator for detection can be formed.

Further, as in the fifth aspect of the present invention, by providing the buffer torsional oscillator between the tuning fork oscillator and the detection torsional oscillator, the torsional vibration propagated from the detection torsional oscillator to the outside is provided. Can be relaxed by the buffering torsional oscillator, and the vibration energy leaking to the outside through the support beam and the support frame can be extremely reduced.

[0036]

Embodiments 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 technique are designated by the same reference numerals, and the description thereof will be omitted.

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

In the figure, 31 indicates an angular velocity sensor according to this embodiment, and 32 indicates a plate-shaped substrate made of a single crystal silicon material.

Reference numeral 33 denotes a support frame fixed on the substrate 32 and formed in a large frame shape with a polysilicon material.
The support frame 33 includes support beams 34 and 3 which serve as tuning fork shafts described later.
Reference numeral 4 is formed so as to project inward in the Y-axis direction, which is the tuning fork axis.

Here, each of the support beams 34, 34 has first support beam portions 35, 35 for connecting the support frame 33 to a detection torsion oscillator 40, which will be described later, and the detection torsion oscillator 40.
Second support beam portions 36 and 3 for connecting the tuning fork vibrator 37 with the tuning fork vibrator 37.
6 and the second support beam portions 36 extend in the Y-axis direction toward the center of the support frame 33.
A and 36A, and U-shaped support beam portions 36B and 36B that are connected to the rod-shaped support beam portions 36A and are formed in a substantially U-shape having tip portions 36B1 and 36B1. Further, each arm portion 39 of the tuning fork vibrator 37 is connected to each tip portion 36B1 of each U-shaped support beam portion 36B.

Reference numeral 37 denotes a tuning fork vibrator 37 which is located on the substrate 32 and is made of a polysilicon material in a small frame shape. The tuning fork vibrator 37 is a pair of vibrations provided in a position parallel to the Y axis. It is composed of plates 38, 38, and substantially U-shaped arm portions 39, 39 connected to the respective vibration plates 38 and forming 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 arm portions 39, the tuning fork vibrator 37 is supported in a floating state on the substrate 32.

In the tuning fork vibrator 37, a part P which is a node of tuning fork vibration (fixing point of tuning fork vibration) when each vibrating plate 38 vibrates in tuning fork is present on the arms 39, 39. The U-shaped support beam portion 3 is provided at the position of the portion P serving as the node.
By connecting the tip portions 36B1 of 6B, the portion P serving as a node of the tuning fork vibrator 37 is fixed by the support beam 34.

Reference numeral 40 denotes a detection torsion oscillator which is located and connected between the support frame 33 and the tuning fork oscillator 37. The detection torsion oscillator 40 has each first support beam portion 35 and each first torsion beam oscillator 35. It is held by the second support beam portion 36 and is formed in a medium frame shape by a polysilicon material, and the torsional vibration due to the Coriolis force generated in the tuning fork vibrator 37 is transmitted.

Reference numeral 41 designates a fixed electrode, which is fixed to the central portion of the substrate 32.

Reference numerals 42 and 42 denote vibration generating portions as vibration generating means provided between the left and right vibrating plates 38 and 38 with the fixed electrode 41 sandwiched therebetween, and the vibration generating portions 42 are opposed to each other. It is composed of a side surface 38A of 38 and a side surface 41A of the fixed electrode 41. And each side 38A, 4
By applying a vibration drive signal to 1A, an electrostatic force is generated between them, and this vibration plate 3
Reference numeral 8 oscillates in the same magnitude in opposite directions as indicated by arrows A1 and A2, and the tuning fork vibrator 37 generates 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, and a rectangular groove 43A is formed in the central portion of the glass substrate 43 and is joined to the support frame 33 by anodic bonding, adhesive or the like. There is. The cover is not limited to the glass substrate 43 and may be another insulating material (for example, ceramic, resin, etc.).

Reference numerals 44, 44, ... Show detection electrodes as vibration displacement detection means, and each detection electrode 44 has an upper surface of the torsion oscillator 40 for detection and a glass substrate 43 facing this surface.
A film is formed in the concave groove 43A by an aluminum thin film or the like. The detection electrode 44 provided on the detection torsional oscillator 40 is formed as a film via 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 respective support beams 34, the tuning fork vibrator 37 and the detection torsion vibrator 40 diffuse a boron or the like to form a low resistance polysilicon film. Is formed by.

The angular velocity sensor 31 according to this embodiment is constructed as described above, and the detecting operation will be described below.

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 the tuning fork about the tuning fork axis (Y axis) in the opposite direction such as the directions A1 and A2. In this state, when a rotational force of angular velocity ω acts around the tuning fork axis, Coriolis forces F1 and F2 are generated on each diaphragm 38 in a direction orthogonal to the tuning fork axis and the tuning fork vibration direction. Due to the Coriolis forces F1 and F2, a torque around the tuning fork axis acts on the detection torsional oscillator 40 via the second support beam portion 36, and torsional vibration is generated in the detection torsional oscillator 40.

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

Further, in the angular velocity sensor 31 according to the present embodiment, paying attention to the fixed point (node) having no amplitude, which is always present when an object vibrates, the portion P of the tuning fork vibrator 37 that becomes the node of tuning fork vibration is Each of the arm portions 3 of the tuning fork vibrator 37 is formed by each tip portion 36B1 of the U-shaped support beam portion 36B that constitutes the support beam 34.
Since 9 is fixed, it is possible to reduce the transmission of vibration energy due to the tuning fork vibration from the tuning fork vibrator 37 to the outside through the support beam 34 that supports the tuning fork vibrator 37. Then, each diaphragm 38 can be largely displaced in the directions of arrows A1 and A2 to bring them into 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, the torsional vibration of the detection torsional oscillator 40 can be increased, and the detection sensitivity of the angular velocity sensor 31 can be increased. Can be significantly improved.

Further, by fixing the portion P of the tuning fork vibrator 37, which serves as a node in the tuning fork vibration, with each tip end portion 36B1 of the U-shaped support beam portion 36B constituting the support beam 34,
The tip portions 36B1 and the like can be prevented from vibrating due to vibration energy, and the vibration of the support beam 34 and the like can be substantially eliminated, the durability of each connecting portion of the support beam 34 and the like can be improved, and the angular velocity sensor The sensor life of 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, and the support frame 3
3, the support beams 34, the tuning fork vibrator 37, and the torsional vibrator 40 for detection are integrally formed in a thin film shape with a polysilicon material on the same plane. Therefore, when manufacturing the angular velocity sensor 31, 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. The tuning fork vibrator 37 and the detection torsion vibrator 40 are patterned. Thereby, the small-sized angular velocity sensor 31 can be easily manufactured, and a large number of silicon wafers can be taken, so that the productivity of the angular velocity sensor 31 can be improved.

Next, a second embodiment of the present invention will be described with reference to FIGS.
The present embodiment is characterized in that the torsional oscillator for detection is formed in a single plate shape located at the center of the angular velocity sensor. In this embodiment, the above-mentioned first
The same components as those of the embodiment are given the same reference numerals and the description thereof will be omitted.

In the figure, 51 indicates an angular velocity sensor according to this embodiment, and 52 indicates a plate-like substrate made of a single crystal silicon material.

Reference numeral 53 denotes a support frame fixed on the substrate 52 and formed in a large frame shape by a polysilicon material.
Support beams 54, 54 are formed on the support frame 53 so as to extend inward in the Y-axis direction, which is the tuning fork axis.

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

Reference numeral 57 denotes a tuning fork vibrator 57 formed on the substrate 52 and formed of a polysilicon material in a medium frame shape. The tuning fork vibrator 57 is a pair provided so as to be parallel to the Y axis. Vibration plates 58, 58, and substantially U-shaped arm portions 59, 59 connected to the vibration plates 58 to form the tuning fork vibrator 57 in a frame shape. Further, since the tuning fork vibrator 57 is connected to the support frame 53 through the support beams 54 at the respective arm portions 59, the tuning fork vibrator 57 is supported in a floating state on the substrate 52.

In the tuning fork vibrator 57, the part P which is a node of tuning fork vibration (fixing point of tuning fork vibration) when each vibrating plate 58 vibrates is present on the arms 59, 59. The portion P serving as the node coincides with each tip portion 56A of the U-shaped support beam portion 56.

60, 60 are formed on the side surface of the vibrating plate 58 facing the outside, and a plurality of (for example, four) electrode plates 60A,
.., the vibrating-side comb-shaped electrodes 60 are arranged so as to face the electrode plates 63A of the fixed-side comb-shaped electrode 63, which will be described later.

Reference numeral 61 denotes a plate-like detection torsional vibrator which is connected to each arm 59 of the tuning fork vibrator 57 and is located at the center of the angular velocity sensor 51. The detection torsional vibrator 61 is
A detection diaphragm 61A to which the vibration displacement from the tuning fork vibrator 57 is transmitted, and rod-shaped bar-shaped arm portions 61B and 61B extending in the Y-axis direction to hold the detection diaphragm 61A,
Each rod-shaped arm portion 61B is formed in a substantially U-shape on the tip end side, and the connecting portion at the tip is a tip end portion 56A of the U-shaped support beam portion 56.
It is composed of U-shaped arms 61C and 61C connected to the tuning fork vibrator 57 at a position corresponding to 56A.

Reference numerals 62 and 62 denote fixed electrodes that are fixedly positioned on the left and right sides of the substrate 52, and a plurality of fixed electrodes are formed on each of the fixed electrodes 62 so as to project toward the respective vibrating plates 58 located inside. Fixed side comb-shaped electrodes 63, 63 having 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 diaphragm 58, and this electrostatic force causes each diaphragm 58 to move. As indicated by arrows A1 and A2, they vibrate in opposite directions with the same magnitude, and the tuning fork vibrator 57 generates tuning fork vibration about the tuning fork axis (Y axis).

Reference numerals 64 and 64 denote vibration generating portions as vibration generating means provided between the vibrating plates 58 and 58 and the fixed electrodes 62 and 62, and each of the vibration generating portions 64 is a comb-shaped electrode 60.
And 63. And each comb-shaped electrode 6
By giving a vibration driving signal to 0 and 63, each diaphragm 58 is indicated by arrows A1 and A2 by the electrostatic force between them.
Vibrate 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 central portion of the glass substrate 65.

Reference numerals 66 and 66 denote detection electrodes as vibration displacement detection means. Each detection electrode 66 is provided on the upper surface of the torsion torsion oscillator 61 and on the concave groove 65A of the glass substrate 65 facing this surface. Is formed by an aluminum thin film or the like. The detection electrode 66 provided on the detection torsion oscillator 61 is an insulating film (not shown) made of silicon oxide or the like.
The film is formed through the.

The angular velocity sensor 51 according to the present embodiment having the above-mentioned configuration has the same detection operation as that of the angular velocity sensor 31 according to the first embodiment.

Therefore, the angular velocity sensor 51 according to this embodiment is
Then, since the portion P of the tuning fork vibrator 57 that serves as a node having no amplitude of the tuning fork vibration is fixed at each tip portion 56A of the U-shaped support beam portion 56, the vibration due to the tuning fork vibration from the tuning fork vibrator 57 is generated. The energy is reduced from being transmitted to the outside through the support beam 54 that supports the tuning fork vibrator 57.

As a result, the respective vibrating plates 58 are indicated by the arrows A1 and A.
It can be largely displaced in two directions and 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.

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

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

Further, FIG. 7 to FIG. 9 show a third embodiment according to the present invention. The features of this embodiment are that the support frame 33 of the angular velocity sensor 31 and the detection torsion oscillator 40 according to the first embodiment are provided. This is because a torsional oscillator for buffering was formed between and. In this embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

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

Reference numerals 74 and 74 denote support beams formed so as to project from the support frame 73 toward the inner side in the Y-axis which is the tuning fork axis. The support beams 74 and 74 are respectively supported by the support frame 73 and a torsional vibration for buffering which will be described later. First support beam portions 75, 75 for connecting the child 82
And the buffer torsion oscillator 82 and the detection torsion oscillator 81.
The second support beam portions 76 and 76 for connecting the above and the third support beam portions 77 and 77 for connecting the above-described torsional oscillator 81 for detection and the tuning fork oscillator 78. The third support beam portions 77 include rod-shaped support beam portions 77A and 77A extending inward in the Y-axis direction from the support frame 73, and the rod-shaped support beam portions 7 respectively.
7A, which is composed of substantially U-shaped support beam portions 77B and 77B having tip portions 77B1 and 77B1 and having tip portions 77B1 and 77B1, respectively, and each tip portion 77B1 of each U-shaped support beam portion 77B has a tuning fork vibration. The arms 80 of the child 78 are connected.

Reference numeral 78 denotes a tuning fork vibrator formed on the substrate 72 and formed of a polysilicon material in a small frame shape. The tuning fork vibrator 78 is a pair of vibrating plates 79 provided parallel to the Y axis. , 79 and substantially U-shaped arms 80, 80 which are connected to the respective vibration plates 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 80, the tuning fork vibrator 78 is supported on the substrate 72 in a floating state.

In the tuning fork vibrator 78, a portion P which is a node of tuning fork vibration (fixing point of tuning fork vibration) when each vibrating plate 79 vibrates in tuning fork exists on the arms 80, 80. The U-shaped support beam portion 77B at the position of the portion P serving as the node
The respective tip portions 77B1 of the are fixed to the tuning fork vibrator 78.

Reference numeral 81 is located between the buffer torsion oscillator 82 and the tuning fork oscillator 78, and is a torsion torsion oscillator for detection held by the second support beam portions 76 and the third support beam portions 77. The detection torsional oscillator 81 is formed of a polysilicon material in a medium frame shape, and the torsional vibration due to the Coriolis force generated from each diaphragm 79 of the tuning fork oscillator 78 is transmitted.

Reference numeral 82 denotes a support frame 73 and a torsional vibrator 81 for detection.
Between the first support beam portion 75 and the second support beam portion 76, the buffer torsion torsion oscillator is shown, and the buffer torsion oscillator 82 is the detection torsion vibration. Child 8
It is formed to be larger than 1 and absorbs vibration energy leaking from the detection torsional vibrator 81.

Reference numeral 83 designates a fixed electrode, which is fixed to the central portion of the substrate 72.

Reference numerals 84 and 84 denote vibration generating portions as vibration generating means provided between the vibration plates 79 and 79 and the fixed electrode 83. Each vibration generating portion 84 is a side surface 79 of the vibration plate 79.
A and the side surfaces 83A and 83A of the fixed electrode 83. Then, by applying a vibration drive signal to each of the side surfaces 79A and 83A, an electrostatic force between them causes each diaphragm 79 to generate an electrostatic force between the arrows A1 and A. The plate 79 oscillates in the same magnitude in opposite directions as indicated by arrows A1 and A2, and the tuning fork vibrator 37 generates tuning fork vibration centered on the tuning fork axis (Y axis).

Reference numeral 85 denotes a glass substrate that covers the angular velocity sensor 71, and a rectangular groove 85A is formed in the central portion of the glass substrate 85. The cover is not limited to the glass substrate 85, but may be another insulating material (for example, ceramic, resin, etc.).

Reference numerals 86, 86, ... Depict detection electrodes as vibration displacement detection means. Each detection electrode 86 has an upper surface of the torsion oscillator 81 for detection and a glass substrate 85 facing this surface.
A film is formed in the concave groove 85A by an aluminum thin film or the like. The detection electrode 86 provided on the detection torsional oscillator 81 is formed as a film via an insulating film (not shown) such as silicon oxide.

Since the angular velocity sensor 71 according to the present embodiment thus constructed has the same detecting operation as that of the angular velocity sensor 31 according to the first embodiment, the description thereof will be omitted.

However, also in the angular velocity sensor 71 of this embodiment, since the portion P serving as the node due to the tuning fork vibration of the tuning fork vibrator 78 is fixed by the third supporting beam portion 77, the torsional vibration causes the supporting beam 74. Further, it is possible to reduce loss to the outside through the support frame 73, increase the amplitude due to the tuning fork vibration of each diaphragm 79 of the tuning fork vibrator 78, and improve the detection sensitivity of the angular velocity sensor 71. Can be made.

However, as described above, the tuning fork oscillator 78
Even if the portion P serving as the node is fixed by the support beam 74, it is not possible to prevent the leakage of vibration energy due to a slight positional displacement, and therefore the angular velocity sensor 31 according to the first and second embodiments. , 51, a small amount of vibration energy is lost. Therefore, like the angular velocity sensor 71 of the present embodiment, by providing a buffer torsional vibrator 82 between the support frame 73 and the detection torsional vibrator 81, minute vibration energy is also relaxed and transmitted to the outside. be able to. As a result, the torsional vibration of the detection torsional oscillator 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 outside the detection torsional vibrator 81 only once is described, but the present invention is not limited to this.
It may be formed in multiple layers, triple layers, ....

In each of the above embodiments, the tuning fork vibrator 3 is used.
The electrostatic force was used to generate the tuning fork vibration in each of the vibrating plates 38, 58, 79 of 7, 57, 78, but the present invention is not limited to this, and a piezoelectric body or the like according to the first conventional technique is used. Tuning fork vibration may be generated.

Further, in each of the above embodiments, the tuning fork vibrator 3 is used.
Although the case where the part P which becomes the node of the tuning fork vibration generated at 7, 57 and 78 is set to one is described, in the present invention, when there are a plurality of parts P which become the supporting beams, the part corresponding to the position is selected. A support beam may be formed so as to be fixed.

Furthermore, in each of the above embodiments, the tuning fork vibration 3
7, 57, 78 and the torsional vibrators 40, 61, 81 for detection
The detection sensitivity can be further improved by matching the resonance frequencies of the above.

[0091]

As described above in detail, according to the present invention of claim 1, since the portion of the tuning fork vibrator which becomes the node of the tuning fork vibration is fixed by the support beam, the tuning fork vibrator is not required. Vibration energy due to torsional vibration is reduced from leaking outside through the support beam and the support frame, and each vibration plate of the tuning fork vibrator is
It can be maintained in a high-resonance state, the torsional vibration transmitted to the detection torsional oscillator can be increased, and the angular velocity detection sensitivity in the tuning fork axis direction can be significantly improved.

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

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

On the other hand, in the invention of claim 4, the substrate is made of a single crystal silicon material, and the supporting frame, the supporting beam, the tuning fork vibrator and the torsional vibrator for detection are made of a polysilicon material. If a thin film of silicon material is formed on a substrate and the thin film is patterned by etching or the like, a supporting frame, a supporting beam, a tuning fork oscillator and a torsion oscillator for detection can be easily formed, and the productivity of the angular velocity sensor can be remarkably improved. .

On the other hand, in the fifth aspect of the invention, since the buffer torsional vibrator is provided outside the detection torsional vibrator, leaking torsional vibration from the detection torsional vibrator can be mitigated, and the detected torsional vibration can be reduced. It suppresses the reduction of torsional vibration in the child and improves the detection sensitivity.

[Brief description of drawings]

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

FIG. 2 is a vertical 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 seen 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 the cover cut away.

5 is a vertical cross-sectional view as seen from the direction of arrows VV in FIG.

FIG. 6 is a top view of the angular velocity sensor in FIG. 4 seen 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 the cover cut away.

8 is a vertical cross-sectional view as seen from the direction of arrows VIII-VIII in FIG.

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

FIG. 10 is a perspective view showing an angular velocity sensor according to a first conventional technique.

FIG. 11 is a perspective view showing an angular velocity sensor according to a second conventional technique.

[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 Vibration plate 39, 59, 80 Arm 40 , 61, 81 Detecting torsional oscillator 44, 66, 86 Detecting electrode (vibration displacement detecting means) 82 Buffering torsional oscillator P Section to be a node

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomohisa Hasegawa 2 26-10 Tenjin Tenjin, Nagaokakyo City, Kyoto Stock Company Murata Manufacturing Co., Ltd. (72) Inventor Katsuhiko Tanaka 2 26-10 Tenjin Tenjin, Nagaokakyo, Kyoto Murata Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. A tuning fork vibrator having a substrate, a support frame formed on the substrate, a pair of vibrating plates for vibrating the tuning fork centering on the tuning fork shaft, and the tuning fork oscillator with respect to the substrate. Support beam provided on the tuning fork shaft for supporting the tuning fork shaft by the Coriolis force generated in each diaphragm when an angular velocity about the tuning fork shaft of the tuning fork vibrator is applied. The tuning fork vibrator is provided with a detecting torsional vibrator connected to the tuning fork vibrator to transmit a torsion, and a vibration displacement detecting means for detecting a vibrational displacement of the detecting torsional vibrator as an angular velocity around the tuning fork axis. An angular velocity sensor in which a portion of a vibration of a child, which is a node of tuning fork vibration, is fixed by the support beam. 2. A substrate, a support frame formed on the substrate, and a pair of vibrating plates for vibrating a tuning fork centering on a tuning fork shaft, and the support is provided by an arm portion holding each vibrating plate. 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 with respect to the substrate via the support frame, and the tuning fork vibrator Is connected between the tuning fork vibrator and the support frame so as to transmit a twist due to the Coriolis force generated in each diaphragm when an angular velocity about the tuning fork shaft of the rotation axis is applied. A vibration transducer for detecting the vibration displacement of the detection torsional oscillator as an angular velocity around the tuning fork axis, and the torsional oscillator for detection formed in a frame shape. An angular velocity sensor in which a portion that becomes a node of tuning fork vibration is fixed by the support beam. 3. A substrate, a support frame formed on the substrate, and a pair of vibrating plates for vibrating the tuning fork centering on the tuning fork shaft, the supporting being provided by an arm portion holding each vibrating plate. 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 with respect to the substrate via the support frame, and the tuning fork vibrator In order to transmit the twist due to the Coriolis force generated in each vibrating plate when an angular velocity about the tuning fork shaft as a rotation axis is applied, a plate-like member located inside the tuning fork vibrator and connected on the tuning fork shaft is transmitted. A portion that serves as a node of tuning fork vibration generated from each of the vibrating plates of the tuning fork vibrator, including a detecting torsion vibrator and a vibration displacement detecting unit that detects a vibration displacement of the detecting torsion vibrator as an angular velocity around the tuning fork axis. An angular velocity sensor in which the support beam is fixed. 4. The substrate according to claim 1, wherein the substrate is made of a single crystal silicon material, and the supporting frame, the supporting beam, the tuning fork vibrator and the torsional vibrator for detection are made of a polysilicon material. Angular velocity sensor. 5. The angular velocity sensor according to claim 1, wherein a torsional oscillator for buffering is provided outside the torsional oscillator for detection.