JPH116735A - Angular velocity sensor - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the angular velocity detection sensitivity. Uniform balance of the electric field of the legs prevents vibration leakage. The reliability of conduction between the detection electrode plate on the side surface and the lead electrode on the main surface is improved. SOLUTION: An intersecting range L of excitation electrode plates 4-1 to 4-4.
The terminal end of A is extended to near the sliding end S1 of the leg 1-1. As a result, the effective working length in the direction in which the distortion increases becomes longer, and a larger excitation can be obtained. Electrode plate 5'-1 to 5'-4
Is extended to the vicinity of the sliding end S2 of the leg 1-2. As a result, the effective action length in the direction in which the distortion increases becomes longer, and a larger charge can be obtained. Except for the uppermost portion where the distortion is small, the electrode plate is extended evenly to the vicinity of the sliding ends S1 and S2 to make the balance of the electric field uniform. Electrode plate 5'-1
5'-4 are formed over the main surface and side surfaces of the leg 1-2. As a result, the width of the electrode plate extending from the side surface to the main surface is increased, and the reliability of conduction with the main surface lead electrode is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a rotational angular velocity acting around a direction of expansion and contraction of a leg of a vibrator element when the vibrator element is vibrating by applying an AC voltage to an excitation electrode. The present invention relates to an angular velocity sensor that detects a voltage based on a voltage signal generated at a detection electrode.

[0002]

2. Description of the Related Art A vibrator vibrating along a predetermined direction,
For example, when a vibrator vibrating along the X axis in the orthogonal coordinate axis plane (XY plane) rotates around the Y axis, a Coriolis force is applied to the vibrator in the Z axis direction (perpendicular to the XY plane). Occurs. Since this Coriolis force is determined in proportion to the magnitude of the angular velocity, if the Coriolis force is directly measured as the amount of deflection displacement of the vibrator, directly by the piezoelectric effect of the piezoelectric element, capacitance change, etc. The magnitude of the rotational angular velocity acting around the Y axis of the child can be obtained. For this reason,
2. Description of the Related Art A vibrating vibrator is mounted on a vehicle, an aircraft, or the like as an angular velocity detecting element, and its running or flight trajectory is recorded, and yaw rate generated at the time of turning is detected.
Further, the angular velocity detecting element is mounted on a robot, and is applied to attitude control and the like.

FIG. 6 is a diagram showing a main part of a conventional angular velocity sensor using quartz. In the figure, (a) is a perspective view,
FIG. 2B is an enlarged view showing an electrode arrangement and a connection state in FIG. In the figure, 1 is a U-shaped vibrator element (quartz plate), 2-1 to 2-4 are electrode plates for excitation, 3-1 to 3-4 are electrode plates for detection, and The electrode plates 2-1 to 2-4 are used as components of the excitation electrode 2, and the detection electrode plates 3-1 to 3-4 are used as components of the detection electrode 3. The excitation electrode plates 2-1 to 2-4 are provided on the front and back (main surface) and left and right (side surfaces) of one leg 1-1 of the vibrator element 1, and the detection electrode plates 3-1 to 3-3. -4 are formed on the left and right (side surfaces) of the other leg portion 1-2 of the vibrator element 1.

[0004] In this angular velocity sensor, FIG.
As shown in FIG. 2, the excitation electrode plates 2-1 and 2-3 are commonly connected to the terminal P1, and the excitation electrode plates 2-2 and 2 are connected.
-4 are commonly connected to a terminal P2.
2 is applied with an AC voltage. For this reason, at one time, an electric field is generated as shown by an arrow in FIG. 6B, and then an electric field in the opposite direction is generated, so that one leg 1-1 of the vibrator element 1 further moves. The other leg 1-2 also interlocks and vibrates left and right while expanding and contracting in the longitudinal direction.

Here, the vibration direction (excitation direction) of the legs 1-1 and 1-2 is the X-axis direction, and FIG.
The direction in the paper plane in FIG.
If the expansion and contraction direction of −2 is the Y axis direction and the direction perpendicular to the XY plane (the direction perpendicular to the plate surface of the transducer element 1) is the Z axis direction, the rotation angular velocity acts around the Y axis. , A vibration component in the Z-axis direction is generated by the Coriolis force. Since the magnitude of this vibration component is proportional to the Coriolis force, the other leg 1-2 of the vibrator element 1 generates a pole charge according to the direction of vibration with a magnitude proportional to the rotational angular velocity. I do.

As a result, as shown in FIG. 6B, the terminal P3 which connects the detection electrode plates 3-1 and 3-4 in common and the detection electrodes 3-2 and 3-3 are connected. In some cases, a charge is generated in the direction of the arrow and then in the opposite direction between the terminal P4 and the terminal P4 connected in common, and a voltage signal e corresponding to the Coriolis force is generated.
s is obtained. Depending on the magnitude of this voltage signal es, Y
The magnitude of the rotational angular velocity acting around the axis can be known. The voltage signal es is basically obtained as a sine curve. By comparing the phase of the waveform of the voltage signal es with the waveform of the excitation vibration signal e (excitation waveform), the lead angle of the phase is used to determine the rotational angular velocity. You can know the direction.

The amplitude of the excitation vibration signal e applied between the terminals P1 and P2 is kept constant by a temperature compensating circuit (not shown) even if the various constants and the vibration mode of the element change due to a temperature change. The amplitude is kept.

[0008]

However, in the conventional angular velocity sensor shown in FIG. 6, the intersection area LA of the electrode plates 2-1 to 2-4 forming the excitation electrode 2 and the electrode forming the detection electrode 3 are determined. The intersection range LB of the plates 3-1 to 3-4 is short. That is, the sliding ends S1 and S2 of the legs 1-1 and 1-2 are located at the roots of the legs 1-1 and 1-2, but the intersections of the excitation electrode plates 2-1 to 2-4 are provided. Range LA
The end of the crossing range LB of the detection electrode plates 3-1 to 3-4 is apart from the sliding ends S1 and S2. Sliding end S
1 and S2 have the largest distortion. Conventionally, since the vicinity of the sliding ends S1 and S2 is not included in the intersection ranges LA and LB as the effective working length, the leg 1-
1 cannot obtain a larger excitation, and the legs 1-2 cannot obtain a larger charge with respect to the rotation around the Y axis, and the detection sensitivity of the angular velocity decreases. In this angular velocity sensor, the excitation electrode plates 2-1 and 2-3 are positioned near the base,
Since each pair of −2 and 2-4 is turned around in the vicinity of the uppermost portion, the balance of the electric field is made non-uniform near the base serving as the sliding end in the leg 1-1. On the other hand, the electrode plates for detection are 3-2 and 3-3 near the root,
Since 1,3-4 is routed near the uppermost portion, the balance of the electric field is made nonuniform both near the uppermost portion and near the root. For this reason, there is a possibility that vibration leakage (vibration having a right-angle component) occurs in both the legs 1-1 and 1-2 with respect to the vibration in the target direction (X-axis direction).

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to make it possible to increase the angular velocity detection sensitivity and to make the electric field balance of the legs uniform. An object of the present invention is to provide an angular velocity sensor capable of preventing vibration leakage.

[0010]

In order to achieve such an object, a first invention (an invention according to claim 1) provides an angular velocity sensor using a U-shaped vibrator element in one of leg portions. For at least one of the excitation electrode formed on the other side and the detection electrode formed on the other leg, the end of the intersection area of each electrode plate constituting the electrode is extended to near the sliding end of the leg on which the electrode is formed. It is a thing. According to a second invention (an invention according to claim 2), in an angular velocity sensor using an H-type vibrator element, an excitation electrode formed on a first leg and a detection electrode formed on a second leg are formed. For at least one of the electrodes, the end of the intersecting range of each electrode plate forming the electrode is extended to near the sliding end of the leg on which the electrode is formed. According to the first invention and the second invention,
For both or one of the excitation electrode and the detection electrode,
The end of the intersecting range of each electrode plate constituting the electrode is extended to the vicinity of the sliding end of the leg on which the electrode is formed, and the effective working length in the direction in which the distortion increases is increased. In addition, it is possible to extend the electrode evenly to the vicinity of the sliding end except for the uppermost portion where the distortion is small, and to make the balance of the electric field uniform.

The third invention (the invention according to claim 3) is the first invention.
In the invention and the second invention, each electrode plate constituting the detection electrode is formed so as to extend over the main surface and the side surface of the leg portion on which the electrode is formed. According to the invention,
Each electrode plate constituting the detection electrode extends over the main surface and the side surface of the leg, so that the width of the electrode plate for detection from the side surface to the main surface is increased, and the detection electrode plate on the side surface and the main surface. Reliability of conduction with the lead electrode can be improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. [Embodiment 1] FIGS. 1A and 1B are views showing a main part of an embodiment of the present invention. FIG. 1A is a perspective view, and FIG. It is a figure which expands and shows a state.

In FIG. 1, reference numeral 1 denotes a U-shaped vibrator element (quartz plate), 4-1 to 4-4 denote excitation electrode plates, and 5-1.
5-4 are electrode plates for detection, and the electrode plates 4-1 to 4-
4 is a component of the excitation electrode 4, and the electrode plates 5-1 to 5-4
Are the components of the detection electrode 5. Electrode plate 4 for excitation
Reference numerals -1 to 4-4 denote electrode plates 5 for detection on the front and back (main surface) and left and right (side surfaces) of one leg 1-1 of the vibrator element 1.
-1 to 5-4 are formed on the left and right (side surfaces) of the other leg portion 1-2 of the vibrator element 1.

In this angular velocity sensor, FIG.
As shown in FIG. 5, the excitation electrode plates 4-1 and 4-3 are commonly connected to the terminal P1, and the excitation electrode plates 4-2 and 4-4 are connected to the terminal P1.
-4 are commonly connected to a terminal P2.
2 is applied with an AC voltage. For this reason, at one time, an electric field is generated as shown by an arrow in FIG. 1B, and then an electric field in the opposite direction is generated, so that one leg 1-1 of the vibrator element 1 further moves. The other leg 1-2 also interlocks and vibrates left and right while expanding and contracting in the longitudinal direction.

Here, the vibration direction (excitation direction) of the legs 1-1 and 1-2 is the X-axis direction, and FIG. 1 is orthogonal to the X-axis direction.
The direction in the paper plane in FIG.
If the expansion and contraction direction of −2 is the Y axis direction and the direction perpendicular to the XY plane (the direction perpendicular to the plate surface of the transducer element 1) is the Z axis direction, the rotation angular velocity acts around the Y axis. , A vibration component in the Z-axis direction is generated by the Coriolis force. Since the magnitude of this vibration component is proportional to the Coriolis force, the other leg 1-2 of the vibrator element 1 generates a pole charge according to the direction of vibration with a magnitude proportional to the rotational angular velocity. I do.

Thus, as shown in FIG. 1B, the terminal P3 which connects the detection electrode plates 5-1 and 5-4 in common and the detection electrodes 5-2 and 5-3 are connected. In some cases, a charge is generated in the direction of the arrow and then in the opposite direction between the terminal P4 and the terminal P4 connected in common, and a voltage signal e corresponding to the Coriolis force is generated.
s is obtained. Depending on the magnitude of this voltage signal es, Y
The magnitude of the rotational angular velocity acting around the axis can be known. The voltage signal es is basically obtained as a sine curve. By comparing the phase of the waveform of the voltage signal es with the waveform of the excitation vibration signal e (excitation waveform), the lead angle of the phase is used to determine the rotational angular velocity. You can know the direction.

Here, the difference from the conventional angular velocity sensor shown in FIG. 6 is that the electrode plates 4-1 to 4-4 constituting the excitation electrode 4 are different.
-4, and the electrode plates 5-1 to 5- constituting the detection electrode 5
4 in shape and arrangement.

That is, in this embodiment, the leg 1-
1, the electrode plate 4-1 is formed on the right side 1-1R,
The lower end of the electrode plate 4-1 is extended to the root of the leg 1-1, and the lead electrode (principal surface) from the front main surface 1-1F side on the inclined surface 1-1a at the root of the leg 1-1. Lead electrode)
6-1. The electrode plate 4-3 formed on the left side surface 1-1L of the leg 1-1 is formed similarly to the electrode plate 4-1.

The electrode plate 4-2 is formed on the front main surface 1-1F of the leg 1-1, and the lower end of the electrode plate 4-2 is located at a position lower than the base of the leg 1-1. It extends further below, that is, further below the sliding end S1 of the leg 1-1. Electrode plate 4 formed on back main surface 1-1B of leg 1-1
-4 in the same manner as the electrode plate 4-2, at the base (sliding end S
1) are formed.

As a result, the end of the intersecting range LA of the electrode plates 4-1 to 4-4 is extended to the vicinity of the sliding end S1 of the leg 1-1, and the effective working length in the direction in which the distortion increases becomes longer. , A larger excitation is obtained in the legs 1-1. In addition, since the electrode plates 4-1 to 4-4 are evenly extended to the vicinity of the sliding end S1 except for the uppermost portion where the distortion is small, the balance of the electric field becomes uniform and vibration leakage is prevented.

On the other hand, the leg 1-2 has a right side surface 1-2.
The electrode plate 5-1 is formed in front of R. The tip of the electrode plate 5-1 is extended to the base of the leg 1-2, and the inclined surface 1- of the base of the leg 1-2 is formed. 2b, the front side main surface 1-
It is connected to a lead electrode (principal surface lead electrode) 6-2 from the 2F side. Further, the electrode plate 5-2 is formed behind the right side surface 1-2R of the leg portion 1-2, but the lower end of the electrode plate 5-2 is extended to the base of the leg portion 1-2, and The bottom surface of the portion 1-2 is coupled to the lead electrode (principal surface lead electrode) 6-3 from the back principal surface 1-2B side at the inclined surface 1-2b at the root. An electrode plate 5 formed on the left side surface 1-2L of the leg portion 1-2.
3 and 5-4 are also formed up to the root (sliding end S2) as in the case of the electrode plates 5-2 and 5-1.

As a result, the end of the intersecting range LB of the electrode plates 5-1 to 5-4 is extended to the vicinity of the sliding end S2 of the leg 1-2, so that the effective working length in the direction in which the distortion increases becomes longer. , A greater charge is obtained in the legs 1-2 for rotation about the Y axis. In addition, since the electrode plates 5-1 to 5-4 are evenly extended to the vicinity of the sliding end S2 except for the uppermost portion where the distortion is small, the balance of the electric field becomes uniform, and vibration leakage is prevented.

By the way, conventionally, there has been a reason that the electrode plate could not be arranged up to the base of the leg. For example, in FIG. 1A, the electrode plates 5-1 and 5-2 of the leg 1-2 are arranged up to the base of the leg 1-2. Such electrode plates 5-1 and 5-2 are formed by photolithography. That is, first, a metal electrode film is deposited on the vibrator element. Then, a photoresist is applied and exposed with a mask. Thereby, the photoresist is left only in the masked portion. Next, the metal electrode film where the photoresist is not left is removed by etching, and the photoresist is peeled off to form an electrode plate.

However, in the conventional photolithography process, the photoresist is hard to adhere to corners due to the influence of surface tension and the like, and the metal electrode film at the corners is removed during etching. That is, regarding the electrode plate 5-1, the main surface lead electrode 6-2 coupled to the electrode plate 5-1 has a conduction failure at the corner portion 1-2c as shown in FIG. As a remedy, a deposition mask having a partial slit is used, and metal is skipped through the slit 100 of the deposition mask to eliminate a conduction failure portion. At this time, the metal from the slit 100 jumps to the back, and the electrode plates 5-1 and 5-2 are short-circuited on the inclined surface 1-2b. In order to prevent such a short circuit, the electrode plates 5-1 and 5-2 need to have a stepped structure, and the intersection area LB between the electrode plates 5-1 and 5-2 is required.
Is separated from the sliding end S2.

The present applicant has made continuous improvements in the method of applying a photoresist in a photolithography process, thereby perfecting the application of the photoresist and leaving a metal electrode film in a corner portion which has been removed by etching in the past. succeeded in. Due to this success, the step of eliminating the portion with poor conduction later becomes unnecessary, and in FIG.
The end of the intersection range LA of the electrode plates 4-1 to 4-4 and the end of the intersection range LB of the electrode plates 5-1 to 5-4 can be extended to the vicinity of the sliding ends S1 and S2.

[Embodiment 2] FIG. 3 is a view showing a main part of another embodiment of the present invention, and FIG.
FIG. 2B is an enlarged view showing the electrode arrangement and the connection state in FIG. In this angular velocity sensor, the detection electrode plates 5'-1 to 5'-4 are formed over the main surface and side surfaces of the leg 1-2. That is, the electrode plate 5'-1 straddles the front side main surface 1-2F and the right side surface 1-2R, and the electrode plate 5'-2 straddles the back side main surface 1-2B and the right side surface 1-2R. Electrode plate 5'-3 is attached to front side main surface 1
-2F and the left side surface 1-2L, the electrode plate 5'-
4 is formed over the back side main surface 1-2B and the left side surface 1-2L.

Thus, the width of the electrode plate for detection from the side surface to the main surface in the leg portion 1-2 becomes extremely large, and the connection between the electrode plate for side surface detection and the main surface lead electrode is ensured. And the reliability of conduction becomes extremely high. That is, in the first embodiment, the turning is performed at the corners (corners 1-2a and 1-2c shown in FIG. 2) connecting the detection electrode plate on the side surface of the leg 1-2 to the main surface lead electrode. As a result, the wraparound width is small and the reliability of conduction is low. On the other hand, in the third embodiment, since the wrapping is performed at the ridge line of the leg 1-2, the wrapping width is large,
High continuity reliability. The wraparound of the leg 1-2 at the ridgeline is also realized by improving the photoresist coating method, as in the case of the corner.

[Embodiment 3] FIG. 4 is a perspective view of an angular velocity sensor showing another embodiment of the present invention. In this angular velocity sensor, an H-shaped vibrator element 7 is used. Then, of the four legs 7-1 to 7-4 of the vibrator element 7, the excitation electrodes 8 and 9 are formed on the legs 7-1 and 7-2, and the legs 7-3 and 7- 4 shows detection electrodes 10 and 1
1 are formed. In this case, the shape and arrangement of the electrode plates 8-1 to 8-4 constituting the excitation electrode 8 and the electrode plates 9-1 to 9-4 constituting the excitation electrode 9 are the same as those of the excitation electrode plate shown in FIG. It is the same as 4-1 to 4-4. Also,
The shape and arrangement of the electrode plates 10-1 to 10-4 constituting the detection electrode 10 and the electrode plates 11-1 to 11-4 constituting the detection electrode 11 are the same as those of the detection electrode plate 5-1 shown in FIG.
5-4.

Embodiment 4 FIG. 5 is a perspective view of an angular velocity sensor showing another embodiment of the present invention. In this angular velocity sensor, the four legs 7-1 to 7-
4, the excitation electrodes 8 and 9 are formed on the legs 7-1 and 7-2, and the detection electrodes 10 'are formed on the legs 7-3 and 7-4.
And 11 '. In this case, the shape and arrangement of the electrode plates 8-1 to 8-4 constituting the excitation electrode 8 and the electrode plates 9-1 to 9-4 constituting the excitation electrode 9 are the same as those of the excitation electrode plate shown in FIG. It is the same as 4-1 to 4-4. Further, an electrode plate 10'-1 constituting the detection electrode 10 '
-10'-4 and electrode plate 1 constituting detection electrode 11 '
The shapes and arrangement of 1'-1 to 11'-4 are the same as those of the detection electrode plates 5'-1 to 5'-4 shown in FIG.

In each of the above-described embodiments, for both the excitation electrode and the detection electrode, the end of the intersection range of each electrode plate constituting the electrode is extended to near the sliding end of the leg on which the electrode is formed. However, one of the excitation electrode and the detection electrode may be configured such that the end of the crossing range of each electrode plate constituting the electrode extends to near the sliding end of the leg on which the electrode is formed.

In Embodiments 3 (FIG. 4) and 4 (FIG. 5), the excitation electrodes are formed on the legs 7-1 and 7-2, and the detection electrodes are formed on the legs 7-3 and 7-4. Was formed,
Detection electrodes are provided on the legs 7-1 and 7-2, and the legs 7-3 and 7-4.
Alternatively, an excitation electrode may be formed. Various other combinations are also conceivable. Excitation electrodes are provided on the legs 7-1 and 7-3, detection electrodes are provided on the legs 7-2 and 7-4, and a leg 7 is provided.
Excitation electrodes are attached to legs 7-1 and 7-4, and excitation electrodes are attached to legs 7-1 and 7-4.
A detection electrode may be formed on 3, 7-4.

[0032]

As is apparent from the above description, according to the present invention, in the first invention and the second invention, both or one of the excitation electrode and the detection electrode intersects each electrode plate constituting the electrode. The end of the range is extended to near the sliding end of the leg on which the electrode is formed, the effective working length in the direction in which the distortion increases is increased, and the detection sensitivity of the angular velocity is increased. In addition, the electrodes are evenly extended to the vicinity of the sliding end except for the uppermost portion where the distortion is small, so that the electric field can be balanced evenly, and vibration leakage can be prevented. Further, according to the third aspect, each electrode plate constituting the detection electrode is straddled over the main surface and the side surface of the leg, so that the width of the electrode plate for detection from the side surface to the main surface is increased. As a result, the reliability of conduction with the main surface lead electrode can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of an embodiment (Embodiment 1) of the present invention.

FIG. 2 is an enlarged view of a main part for explaining the reason why an electrode plate could not be arranged up to the base of a leg in the related art.

FIG. 3 is a diagram showing a main part of another embodiment (Embodiment 2) of the present invention.

FIG. 4 is a perspective view showing another embodiment (Embodiment 3) of the present invention.

FIG. 5 is a perspective view showing another embodiment (Embodiment 4) of the present invention.

FIG. 6 is a diagram showing a main part of a conventional angular velocity sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transducer element (U-shaped), 1-1, 1-2 ... Leg, 1
-1F, 1-2F ... front side main surface, 1-1B, 1-2B ... back side main surface, 1-1R, 1-2R ... right side surface, 1-1L, 1-
2L: left side surface, 4-1 to 4-4: excitation electrode plate, 5-
1-5-4, 5'-1-5'-4 ... electrode plate for detection, S
1, S2: sliding end, 7: vibrator element (H type), 7-1
7-4: Legs, 8-1 to 8-4, 9-1 to 9-4, ... Electrode plates for excitation, 10-1 to 10-4, 11-1 to 11-
4,10'-1 to 10'-4,11'-1 to 11'-4
... Electrode plate for detection.

Claims (3)

[Claims] A U-shaped vibrator element; an excitation electrode formed on one leg of the U-shaped vibrator element; and a detection electrode formed on the other leg. An angular velocity sensor that detects a rotational angular velocity that acts around the expansion and contraction direction of the leg based on a voltage signal generated at the detection electrode while vibrating the vibrator element by applying an AC voltage to an excitation electrode; At least one of the excitation electrode and the detection electrode,
An angular velocity sensor characterized in that the end of the intersection area of each electrode plate constituting the electrode extends to near the sliding end of the leg on which the electrode is formed. 2. An H-shaped transducer element, comprising: an excitation electrode formed on a first leg of the H-shaped transducer element; and a detection electrode formed on a second leg of the H-shaped transducer element. An angular velocity sensor that detects a rotational angular velocity that acts around the expansion and contraction direction of the leg based on a voltage signal generated at the detection electrode while vibrating the vibrator element by applying an AC voltage to an excitation electrode; At least one of the excitation electrode and the detection electrode,
An angular velocity sensor characterized in that the end of the intersection area of each electrode plate constituting the electrode extends to near the sliding end of the leg on which the electrode is formed. 3. The detection electrode according to claim 1, wherein each of the electrode plates constituting the detection electrode is formed over a main surface and a side surface of a leg portion on which the electrode is formed. Angular velocity sensor.