Vibration-type angular velocity sensor

Abstract

By reducing the hard spring effect and increasing the vibration amplitude of the movable part, a vibration-type angular velocity sensor with improved sensitivity is realized. [Solution] The vibration-type angular velocity sensor 1 has a plurality of weights 31-36 and a linear drive beam 42 connecting them, and comprises a movable part 30 in which the weights 31-36 vibrate due to the deflection of the drive beam 42, and a support member 43 connected to the fixed point of the drive beam 42 and fixing the movable part 30 to the base plate 10. The support member 43 has a rotating beam 43a that undulates and bends when the movable part 30 vibrates, and a connecting part 43c that connects the rotating beam 43a and the fixed point of the drive beam 42. Let h1 be the width of the drive beam 42 in a direction perpendicular to the extension direction of the drive beam 42, and let h2 be the width of the rotating beam 43a in a direction perpendicular to the extension direction of the rotating beam 43a, such that h1 / h2 is 1 or less.

Description

[Technical Field]

[0001] This disclosure relates to a vibration-type angular velocity sensor. [Background technology]

[0002] Conventionally, Patent Document 1 has proposed a vibration-type angular velocity sensor having two inner drive weights, each equipped with a detection weight on the inside, and two outer drive weights, each positioned on either side of the two inner drive weights, with these drive weights connected to a drive beam. In this vibration-type angular velocity sensor, the movable part, which consists of four drive weights connected by two drive beams arranged in parallel, is fixed to a substrate via a support member at the fixed point of the drive beam, and the springiness of the support member is smaller than that of the drive beam. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2013-134064 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In recent years, there has been a demand for higher accuracy in angular velocity detection, i.e., improved sensitivity, in this type of vibration-type angular velocity sensor. To improve the sensitivity of a vibration-type angular velocity sensor, one possible approach is to increase the vibration amplitude of the movable part.

[0005] However, in vibration-type angular velocity sensors, if the drive amplitude is increased too much, a hard spring effect occurs, where the spring in the movable part becomes relatively stiff. When the vibration amplitude of the vibrator is increased beyond a predetermined level when the hard spring effect occurs, multiple solutions for the resonant amplitude exist for a single operating frequency, causing the vibration amplitude to become unstable. Due to the influence of this hard spring effect, simply increasing the vibration amplitude does not result in a constant sensitivity, and there is a limit to how much sensitivity can be improved.

[0006] In view of the above, this disclosure aims to provide a vibration-type angular velocity sensor that reduces the effects of the hard spring effect and improves sensitivity by increasing the vibration amplitude of the movable part. [Means for solving the problem]

[0007] According to one aspect of this disclosure, a vibration-type angular velocity sensor is, A movable part (30) has multiple weights (31-36) and a linear drive beam (42) connecting the multiple weights, and the multiple weights vibrate due to the deflection of the drive beam, It comprises a plurality of support members (43) connected to the fixed point of the drive beam and fixing the movable part to the base plate (10), The support member includes a rotating beam (43a) that undulates and bends during vibration of the movable part, a support beam (43b) that supports both sides of the rotating beam on a base plate, and a connecting part (43c) that connects the rotating beam and the drive beam at a fixed point. Let h1 be the width of the drive beam in a direction perpendicular to the extension direction of the drive beam, and h2 be the width of the rotary beam in a direction perpendicular to the extension direction of the rotary beam. Then, h1 / h2 = 1 / R, and 1 / R is less than or equal to 1.

[0008] This vibration-type angular velocity sensor has a movable part with multiple weights and a drive beam connecting them, and a support member connected to the fixed point of the drive beam and fixing the movable part to a substrate. The ratio of the width h1 of the drive beam of the movable part to the width h2 of the rotating beam that constitutes the support member is adjusted. By having h1 / h2 = 1 / R be 1 or less, the hard spring effect is reduced, and sensitivity can be improved by increasing the vibration amplitude of the movable part.

[0009] The reference numerals in parentheses attached to each component indicate an example of the correspondence between that component and the specific components described in the embodiments described later. [Brief explanation of the drawing]

[0010] [Figure 1]It is a top view showing a vibration type angular velocity sensor according to an embodiment. [Figure 2] It is an explanatory diagram of the basic operation of a vibration type angular velocity sensor. [Figure 3] It is a schematic diagram showing the state when an angular velocity is applied to a vibration type angular velocity sensor. [Figure 4] It is a schematic diagram showing a simple model of a vibrator. [Figure 5] It shows the relationship between the load of the mass point in FIG. 4 and the displacement amount of the leaf spring, and is an explanatory diagram for the case where a hard spring effect occurs. [Figure 6] It is a diagram showing the change in resonance characteristics when the vibration amplitude of the vibrator is increased. [Figure 7] It corresponds to an enlarged view of the VII region in FIG. 1, and is an explanatory diagram of the widths of the drive beam and the rotation beam. [Figure 8] It is a diagram showing the simulation result of the change in the non-linearity term when the width of the drive beam is fixed and the width of the rotation beam is changed. [Figure 9] It is a diagram showing the simulation result of the change in the critical amplitude when the width of the drive beam is fixed and the width of the rotation beam is changed.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present disclosure will be described based on the drawings. In the following embodiments, parts that are identical or equivalent to each other will be denoted by the same reference numerals and described.

[0012] (Embodiment) The vibration type angular velocity sensor 1 according to the embodiment will be described. The vibration type angular velocity sensor 1 is a sensor for detecting an angular velocity as a physical quantity, that is, a gyro sensor, and is used, for example, in an in-vehicle application mounted on a vehicle to detect the angular velocity generated in the vehicle. Of course, it can also be applied to other than in-vehicle applications.

[0013] 〔Basic Configuration〕 The vibration-type angular velocity sensor 1 of this embodiment is formed on one side of a plate-shaped substrate 10, as shown in Figure 1, for example. The substrate 10 is made of an SOI substrate, which has a structure in which an embedded oxide film, which serves as a sacrificial layer (not shown), is sandwiched between a support substrate 11 and a semiconductor layer 12. SOI is an abbreviation for Silicon on Insulator. This sensor structure is constructed by etching the semiconductor layer 12 side to the pattern of the sensor structure, partially removing the embedded oxide film, and releasing a part of the sensor structure to put it into a floating state.

[0014] For the sake of explanation, as shown in Figure 1, the direction parallel to the surface of the semiconductor layer 12 and in the left-right direction on the paper will be referred to as the "X-axis direction," the direction perpendicular to the X-axis direction and in the up-down direction on the paper will be referred to as the "Y-axis direction," and the direction perpendicular to the surface of the semiconductor layer 12 will be referred to as the "Z-axis direction." In the case of automotive applications, for example, the vibration-type angular velocity sensor 1 is mounted so that the Z-axis direction, i.e., the thickness direction of the substrate 10, coincides with the up-down direction of the vehicle.

[0015] The semiconductor layer 12 has a pattern shape with a fixed portion 20, a movable portion 30, and a beam portion 40. The fixed portion 20 has an embedded oxide film remaining on at least a part of its back surface and is fixed to the support substrate 11 via the embedded oxide film without being released from the support substrate 11. The movable portion 30 has the embedded oxide film on the support substrate 11 side removed and is in a hollow state that can be released from the support substrate 11 and displaced. The beam portion 40 supports the movable portion 30 and displaces the movable portion 30 in the X-axis and Y-axis directions in order to perform angular velocity detection. The movable portion 30 and the beam portion 40 constitute an oscillator in a vibration-type angular velocity sensor.

[0016] The fixed part 20 has a configuration that includes a support fixed part 21 for supporting the movable part 30, drive fixed parts 22 and 23 to which a drive voltage is applied, and detection fixed parts 24 and 25 used for angular velocity detection.

[0017] The support fixing part 21 is, for example, a frame shape that surrounds the sensor structure, such as the part of the fixing part 20 other than the support fixing part 21 and the movable part 30, and supports the movable part 30 via a beam part 40 connected to its inner wall. The support fixing part 21 only needs to be able to support the movable part 30, and may have a shape other than a frame shape.

[0018] The drive fixing part 22 is a fixing part positioned between the outer drive weight 31 and the inner drive weight 33, which will be described later. The drive fixing part 23 is a fixing part positioned between the outer drive weight 32 and the inner drive weight 34, which will be described later. The drive fixing parts 22 and 23 are configured, for example, with base portions 22a and 23a extending in the Y-axis direction and comb-shaped drive fixing electrodes 22b and 23b connected to the base portions 22a and 23a.

[0019] The base portions 22a and 23a have, for example, electrode pads (not shown), to which bonding wires (not shown) are connected, and a desired AC voltage for driving can be applied externally to the driving fixed electrodes 22b and 23b.

[0020] The fixed driving electrodes 22b and 23b are comb-shaped electrodes positioned opposite to the comb teeth of the comb-shaped movable driving electrodes 31b, 32b, 33b, and 34b, which are provided on the outer driving weights 31 and 32 and the inner driving weights 33 and 34, respectively. Specifically, the fixed driving electrodes 22b and 23b are composed of a plurality of support parts extending in the X-axis direction and a plurality of comb-shaped electrodes extending in the Y-axis direction from each support part. Multiple fixed driving electrodes 22b and 23b are arranged along the Y-axis direction on the surfaces of the base parts 22a and 23a that face adjacent outer driving weights 31 and 32 or inner driving weights 33 and 34.

[0021] The detection fixing parts 24 and 25 are located within a region surrounded by the detection weights 35 and 36, which will be described later and are provided on the inner drive weights 33 and 34. The detection fixing parts 24 and 25 have a base portion 24a and 25a and detection fixing electrodes 24b and 25b.

[0022] The bases 24a and 25a have, for example, electrode pads (not shown), to which bonding wires (not shown) are connected, enabling signal output to the outside. The fixed detection electrodes 24b and 25b are multiple comb-shaped electrodes extending in the Y-axis direction from the bases 24a and 25a, and are positioned opposite each comb tooth of the comb-shaped movable detection electrodes 35b and 36b provided on the detection weights 35 and 36.

[0023] The movable part 30 is a part that displaces in response to the application of angular velocity. The movable part 30 has a configuration that includes multiple weights, namely outer drive weights 31 and 32, inner drive weights 33 and 34, and detection weights 35 and 36. The movable part 30 is configured such that the outer drive weight 31, the inner drive weight 33 which contains the detection weight 35, the inner drive weight 34 which contains the detection weight 36, and the outer drive weight 32 are arranged in this order along the X-axis direction. Hereinafter, the outer drive weights 31 and 32, the inner drive weights 33 and 34 and the detection weights 35 and 36 may be collectively referred to as "weights 31 to 36", and the outer drive weights 31 and 32 and the inner drive weights 33 and 34 may be collectively referred to as "drive weights 31 to 34".

[0024] The outer drive weights 31 and 32 each have mass portions 31a and 32a extending in the Y-axis direction and drive movable electrodes 31b and 32b. The mass portion 31a is positioned opposite the base portion 22a of the drive fixed portion 22. The mass portion 32a is positioned opposite the base portion 23a of the drive fixed portion 23. The outer drive weights 31 and 32 are movable in the Y-axis direction using the mass portions 31a and 32a as weights.

[0025] The drive movable electrodes 31b and 32b are provided on the mass sections 31a and 32a and are comb-shaped electrodes positioned opposite each comb tooth of the comb-shaped drive fixed electrodes 22b and 23b. Specifically, the drive movable electrodes 31b and 32b are composed of a plurality of support sections extending in the X-axis direction and a plurality of comb-shaped electrodes extending from each support section in the Y-axis direction. The drive movable electrodes 31b and 32b are arranged in multiple locations along the Y-axis direction on the surfaces of the mass sections 31a and 32a that face the drive fixed sections 22 and 23.

[0026] The inner drive weights 33 and 34 each have a square-shaped frame-shaped mass section 33a and 34a and a movable drive electrode 33b and 34b. The inner drive weights 33 and 34 are movable in the Y-axis direction using the mass section 33a and 34a as weights.

[0027] The mass sections 33a and 34a have two sides parallel to the X-axis and two sides parallel to the Y-axis, and these two sides are connected to form a frame shape. One side of the mass section 33a along the Y-axis faces the drive fixing section 22 and is provided with a drive movable electrode 33b. One side of the mass section 34a along the Y-axis faces the drive fixing section 23 and is provided with a drive movable electrode 34b. The drive movable electrodes 33b and 34b are comb-shaped electrodes with the same configuration as the drive movable electrodes 31b and 32b, and are positioned opposite the drive fixing electrodes 22b and 23b.

[0028] The detection weights 35 and 36 have a configuration comprising a square-shaped frame-shaped mass section 35a and 36a and a movable detection electrode 35b and 36b. The mass sections 35a and 36a are arranged within the region surrounded by the mass sections 33a and 34a and are supported on the inner wall surface of the inner drive weights 33 and 34 via a detection beam 41, which will be described later, from the beam section 40. The detection weights 35 and 36 are moved in the Y-axis direction together with the inner drive weights 33 and 34. Furthermore, the detection weights 35 and 36 are configured to be movable in the X-axis direction using the mass sections 35a and 36a as weights. The movable detection electrodes 35b and 36b are multiple comb-shaped electrodes extending in the Y-axis direction from the inner wall surface of the mass sections 35a and 36a. The movable detection electrodes 35b and 36b are positioned opposite each comb tooth of the fixed detection electrodes 24b and 25b.

[0029] The beam section 40 has a configuration comprising a detection beam 41, a drive beam 42, and a support member 43. The detection beam 41 is a beam that connects the sides of the inner wall surfaces of the mass sections 33a and 34a that are parallel to the X-axis direction with the sides of the outer wall surfaces of the mass sections 35a and 36a that are parallel to the X-axis direction. The detection beam 41 is displaceable in the X-axis direction. The detection weights 35 and 36 are movable in the X-axis direction relative to the inner drive weights 33 and 34 based on the displacement of the detection beam 41.

[0030] The drive beam 42 connects the drive weights 31-34 and, by bending, allows the drive weights 31-34 to move in the Y-axis direction. The drive beam 42 connects the outer drive weight 31, inner drive weight 33, inner drive weight 34, and outer drive weight 32 in this order. The drive beam 42 is a straight beam along the X-axis direction, and one beam is positioned on each side of the drive weights 31-34 in the Y-axis direction. The two drive beams 42 are, for example, directly connected to the outer drive weights 31 and 32, and connected to the inner drive weights 33 and 34 via connecting parts 42a, but all of the drive weights 31-34 may also be directly connected. From the viewpoint of reducing the hard spring effect in the oscillator, the width of the two drive beams 42 is less than or equal to a predetermined ratio to the width of the rotating beam 43a, which will be described later. The width of the drive beam 42 and its effect on the hard spring effect will be described later.

[0031] The support member 43 is a member that supports the movable part 30. The support member 43 is provided between the inner wall surface of the support fixing part 21 and the drive beam 42, and supports the multiple weights 31 to 36 that constitute the movable part 30 to the support fixing part 21 via the drive beam 42. The support member 43 has a configuration that includes a rotating beam 43a, a support beam 43b, and a connecting part 43c.

[0032] The rotating beam 43a is a straight beam extending along the X-axis direction, with support beams 43b connected to both ends in the direction of extension. A connecting section 43c is connected to the rotating beam 43a at its central position in the direction of extension. When the sensor is driven, the rotating beam 43a undulates and bends in an S-shape around the connecting section 43c. The width of the rotating beam 43a is set to be greater than or equal to the width of the drive beam 42. Details of this will be described later.

[0033] The support beam 43b is a member that connects both ends of the rotating beam 43a to the support fixing part 21, and is, for example, a linear member. The support beam 43b also plays a role in allowing the multiple weight parts 31 to 36 to move in the X-axis direction when an impact or the like is applied. The connecting part 43c connects the support member 43 to the drive beam 42.

[0034] The above describes the basic configuration of the vibration-type angular velocity sensor 1. The vibration-type angular velocity sensor 1 consists of a pair of angular velocity detection structures, each comprising two outer drive weights, two inner drive weights, and two detection weights in a movable part 30.

[0035] [Sensor activated] Next, the operation of the vibration-type angular velocity sensor 1 will be explained.

[0036] The vibration-type angular velocity sensor 1 receives a driving AC voltage, i.e., a driving voltage, from an external control unit (not shown) that applies a command to the driving fixed parts 22 and 23. When a potential difference is created between these parts and the driving weights 31 to 34, an electrostatic force is generated in the Y-axis direction. Due to the electrostatic force generated between the driving fixed parts 22 and 23 and the driving weights 31 to 34, the driving weights 31 to 34 vibrate in the Y-axis direction, as shown in Figure 2. Specifically, the outer driving weight 31 and the inner driving weight 33 vibrate in opposite directions in the Y-axis direction, and the outer driving weight 32 and the inner driving weight 34 vibrate in opposite directions in the Y-axis direction. At this time, the inner driving weights 33 and 34 vibrate in opposite phases in the Y-axis direction. Hereinafter, the above driving state shown in Figure 2 may be referred to as the "driving mode". The driving mode can be said to be the basic operation of the vibration-type angular velocity sensor 1.

[0037] The control unit, which is not shown in the diagram above, is composed of, for example, a computer with a processor and memory, and peripheral circuits, and performs various calculations and processes based on the program stored in the memory. This control unit monitors the vibration in the Y-axis direction of each of the drive weights 31 to 34 while changing the frequency of the drive voltage, and adjusts it so that the frequency becomes the drive resonance frequency.

[0038] Furthermore, in the above-described driving mode, the drive beam 42 undulates in an S-shape, allowing the drive weights 31-34 to move in the Y-axis direction, while the portion to which the connecting part 43c is connected acts as a node of amplitude, i.e., a fixed point. The fixed point of the drive beam 42 hardly displaces.

[0039] When an angular velocity is applied to the vibration-type angular velocity sensor 1 around the Z axis in drive mode, the Coriolis force causes the detection weights 35 and 36 to be displaced in the X-axis direction, as shown in Figure 3. This displacement changes the capacitance value of the capacitor formed by the detection movable electrode 35b and the detection fixed electrode 24b, and the capacitance value of the capacitor formed by the detection movable electrode 36b and the detection fixed electrode 25b. The external control unit receives the change in the capacitance value of the capacitors as a detection signal via bonding wires (not shown) connected to the detection fixed parts 24 and 25, for example, and calculates the angular velocity applied to the vibration-type angular velocity sensor 1 based on the detection signal.

[0040] [Hard spring effect and its reduction] Next, we will explain the hard spring effect and its impact on the sensitivity of vibration-type angular velocity sensors.

[0041] The oscillator can be considered as having a mass M and a leaf spring LS connected to the mass M, as shown in Figure 4, with the other end of the leaf spring LS, opposite to the end connected to the mass M, fixed to a stationary object. In Figure 4, the outline of the oscillator when the mass M is not vibrating is shown by a dashed line. When a load F acts on the mass M, for example, due to an external electrostatic force, the leaf spring LS deforms and vibrates. At this time, if the displacement of the leaf spring LS is x, the load F is proportional to the displacement x when it is below a certain value, as shown in Figure 5. However, when the displacement x exceeds a certain value, as shown by the arrow in Figure 4, internal stress due to the stretching and contracting of the leaf spring LS accumulates, causing the leaf spring LS to become relatively less displaceable compared to its initial state, i.e., it becomes stiffer, resulting in a hard spring effect. In other words, when the vibration amplitude of the leaf spring LS exceeds a certain value, the leaf spring LS becomes relatively stiffer due to the hard spring effect.

[0042] Here, the resonance characteristics of the oscillator will be explained with reference to Figure 6. In Figure 6, the horizontal axis represents the frequency required to vibrate the oscillator, and the vertical axis represents the amplitude of the oscillator's vibration. When the peak of the vibration amplitude is small, that is, when the Q factor of the vibration is small, the resonance characteristics will be as shown in the graph by the dashed line, for example, and there will be one vibration amplitude corresponding to the resonance frequency. In other words, when the Q factor of the vibration is small, there is one solution for the resonance amplitude for one operating frequency, so the vibration of the spring will be in a stable state.

[0043] As the Q-factor of the oscillator is increased, the peak of the vibration amplitude, i.e., the resonant amplitude, increases, as shown in the solid and dashed lines in Figure 6, and the resonant frequency shifts to a higher frequency. Here, the maximum value of the vibration amplitude at which there is one resonant frequency corresponding to the resonant amplitude is the critical amplitude x. c Assuming the vibration amplitude is the critical amplitude x c The spring vibration will be stable under the following conditions:

[0044] However, if the Q factor of the vibration is further increased, the vibration amplitude will reach the critical amplitude x c Beyond a certain point, the resonance characteristics become such that a predetermined region including the peak position of the vibration amplitude is shifted significantly to the higher frequency side compared to the region with smaller vibration amplitudes. In this case, although the Q-factor of the vibration increases, there are two solutions: position S1 where the vibration amplitude corresponding to the resonance frequency is maximum, and another position S2. In other words, when the vibration amplitude is increased and the hard spring effect is at work, the vibration amplitude of the spring transitions between two solutions, S1 and S2, at a single operating frequency, making the spring vibration unstable. For this reason, there are limits to improving the sensitivity of vibration-type angular velocity sensors by simply increasing the vibration amplitude during the driving of the spring, i.e., the vibrator.

[0045] As a result of diligent research by the inventors, it was found that the hard spring effect can be reduced by setting the structure such that the ratio of the width of the drive beam 42 to the width of the rotating beam 43a, known as the beam ratio R, is 1 / R or less.

[0046] Here, if we denote the driving force (in N) generated between the fixed driving electrodes 22b and 23b and the opposing movable driving electrodes 33b and 34b as F1, the driving force F1 is expressed by the following equation (1).

[0047] F1 = kx + βx 3 ...(1) In equation (1), k is the spring constant (unit: N / m) of the part of the oscillator that functions as a spring, and is mainly the spring constant of the drive beam 42. In equation (1), x is the displacement (unit: m) of the drive weights 31-34. In equation (1), β is the nonlinearity term (unit: N / m). 3 ) is generally said to be proportional to the thickness, i.e., width, of the beam in the direction of deformation. According to the inventors' research results, it has been found that the hard spring effect can be reduced by making the width of the rotating beam 43a greater than or equal to a predetermined value relative to the drive beam 42 and by reducing the value of the nonlinearity term β.

[0048] For the sake of explanation, as shown in Figure 7, for example, the extension direction of the drive beam 42 will be referred to as "extension direction D1," and the extension direction of the rotating beam 43a, which will be described later, will be referred to as "extension direction D2." Both extension directions D1 and D2 are, for example, parallel to the X-axis direction.

[0049] Here, let h1 be the width of the drive beam 42 in the direction perpendicular to the extension direction D1, and let h2 be the width of the rotary beam 43a in the direction perpendicular to the extension direction D2, and let the ratio of h1 to h2 be the beam ratio R. The beam ratio R is h2 / h1, that is, the ratio of the width of the rotary beam 43a to the width of the drive beam 42.

[0050] The width h1 of the driving beam 42 was fixed at 16.5 μm, and a simulation evaluation was performed on the non-linearity term β when the width h2 of the rotating beam 43a was changed. As a result, the results shown in Fig. 8 were obtained. In Fig. 8, the calculation results of the reciprocal 1 / R of the beam ratio R at some values of the width h2 are also shown. The simulation evaluation can be performed, for example, by using known numerical analysis software using the finite element method. In the simulation, the width h2 was set to 3.6 μm, 4.6 μm, 5.6 μm, 6.6 μm, 7.6 μm, 8.6 μm, 10.6 μm, 12.6 μm, 14.6 μm, 16.6 μm, 17.6 μm, 27.6 μm, 37.6 μm, 47.6 μm. 1 / R becomes 2.17, 1.13, 1.00, 0.94, 0.60, 0.43, 0.34 at widths h2 of 7.6 μm, 14.6 μm, 16.6 μm, 17.6 μm, 27.6 μm, 37.6 μm, 47.6 μm, respectively.

[0051] The non-linearity term β is about 747×10 9 N / m 3 to about 717×10 9 N / m 3 and greatly decreases in the range where the width h2 is from 3.6 μm to 16.6 μm, and is almost horizontal at about 717×10 9 N / m 3 in the range where the width h2 is 16.6 μm or more. This result suggests that when 1 / R exceeds 1, the thinner the rotating beam 43a, the larger the non-linearity term β, and the greater the influence of the hard spring effect. That is, when the rotating beam 43a is designed to be thinner than the driving beam 42, the variation of the non-linearity term β when the widths h1 and h2 of the driving beam 42 and the rotating beam 43a vary due to processing errors is also large, and it can be said that it is difficult to obtain the effect of improving the sensitivity by increasing the vibration amplitude.

[0052] Conversely, when 1 / R is less than or equal to 1, that is, when the rotating beam 43a is designed to be thicker than the driving beam 42, the value and variation of the non-linearity term β are small, the influence of the hard spring effect is reduced, and the influence of processing errors is also reduced.

[0053] Next, for the data shown in Fig. 8, the critical amplitude xc When calculated, the results shown in Figure 9 were obtained. In Figure 9, similar to Figure 8, the values ​​of 1 / R for some of the width h2 values ​​are shown. Also, the critical amplitude x c This can be calculated using the following equation (2).

[0054]

number

[0055] As shown in Figure 1, the multiple support members 43 arranged in the X-axis direction along the drive beam 42 are, for example, all the same width h2 of the rotating beam 43a, but they may be partially or entirely different as long as 1 / R ≤ 1 is satisfied.

[0056] According to this embodiment, the vibration-type angular velocity sensor 1 has a movable part 30 having a plurality of weights 31-36 and a drive beam 42 connecting them, and a support member 43 connected to the fixed point of the drive beam 42 and fixing the movable part 30 to the substrate 10. In the vibration-type angular velocity sensor 1, the ratio of the width h1 of the drive beam 42 to the width h2 of the rotating beam 43a constituting the support member 43, i.e., 1 / R, is 1 or less. As a result, the vibration-type angular velocity sensor 1 has a nonlinearity term β of a predetermined value or less, and a critical amplitude x c When this value exceeds a predetermined level, these fluctuations become smaller, the hard spring effect is reduced, and sensitivity can be improved by increasing the vibration amplitude.

[0057] (Other embodiments) This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence range. In addition, various combinations and forms, as well as other combinations and forms including one, more, or less of those elements, fall within the scope and concept of this disclosure.

[0058] Furthermore, although the above embodiment describes a typical example where the driving of the drive weights 31-34 and the detection of the displacement of the detection weights 35 and 36 are performed using an electrostatic method, the vibration-type angular velocity sensor 1 is not limited to this example, and the driving and detection may also be performed using a piezoelectric method with piezoelectric material. In the case of the piezoelectric method, for example, the vibration-type angular velocity sensor 1 has a configuration in which, instead of driving and detection electrodes, there are piezoelectric films for driving at both ends of the drive beam 42 and a piezoelectric film for detecting displacement on the detection beam 41. Thus, the vibration-type angular velocity sensor 1 may use other known methods other than the electrostatic method for driving the drive weights 31-34 and detecting the displacement of the detection weights 35 and 36, and some of the components may be changed as appropriate.

[0059] It goes without saying that, in each of the above embodiments, the elements constituting the embodiment are not necessarily essential unless explicitly stated to be particularly essential or unless they are clearly considered essential in principle. Furthermore, in each of the above embodiments, when numerical values ​​such as the number, numerical values, quantities, or ranges of the components of the embodiment are mentioned, the embodiment is not limited to those specific numbers unless explicitly stated to be particularly essential or unless it is clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shape, positional relationship, etc., of the components are mentioned, the embodiment is not limited to those shapes, positional relationships, etc., unless explicitly stated or unless it is clearly limited to a specific shape, positional relationship, etc., in principle. [Explanation of Symbols]

[0060] 10...Substrate, 30...Movable part, 31-36...Weight part, 42...Drive beam, 43...Support member, 43a...Rotating beam, 43b...Support beam, 43c...Connecting part

Claims

[Claim 1] A vibration-type angular velocity sensor, A movable part (30) having multiple weights (31-36) and a linear drive beam (42) connecting the multiple weights, wherein the multiple weights vibrate due to the deflection of the drive beam, The system includes a plurality of support members (43) connected to the fixed point of the drive beam, which fix the movable part to the base plate (10), The support member comprises a rotating beam (43a) that undulates and bends during vibration of the movable part, a support beam (43b) that supports both sides of the rotating beam on the base plate, and a connecting part (43c) that connects the rotating beam and the drive beam at the fixed point. A vibration-type angular velocity sensor in which the width of the drive beam in a direction perpendicular to the extension direction of the drive beam is h1, the width of the rotating beam in a direction perpendicular to the extension direction of the rotating beam is h2, and h1 / h2 = 1 / R, and 1 / R is 1 or less.

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