Physical sensors and electronic devices

Abstract

To provide a small size physical quantity sensor having a high Q value and a high detection sensitivity, and to provide an electronic apparatus using the same.SOLUTION: A physical quantity sensor 1 includes: a ring part 31 capable of circular-ring oscillation; four support parts 61-64; four beams 71-72 which connect the support parts 61-64 to the parts as a hub of the circular-ring oscillation of the ring part 31; a pair of first mass parts 51 and 52 each of which has a movable part, and which are disposed being opposed to each other in an X1-axis direction via the ring part 31; a pair of second mass parts 53 and 54 each of which has a movable part, and which are disposed being opposed to each other in a Y-axis direction via the ring part 31; oscillation means 4 that causes at least one of the pair of first mass parts 51 and 52 and the pair of second mass parts 53 and 54 to oscillate at a first frequency in a phase opposite to each other. The ring part 31 performs circular-ring oscillations relative to the X-axis direction and the Y-axis direction according to the first frequency.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a physical quantity sensor and an electronic device using the same. [Background technology]

[0002] In recent years, angular velocity sensors that detect angular velocity have been widely used for image stabilization of imaging devices such as digital cameras, and for attitude control of mobile body navigation systems for vehicles and the like that use GPS signals. Also known as angular velocity sensors are those that can detect angular velocity around each of three mutually orthogonal axes using a single sensor (see, for example, Patent Document 1).

[0003] The sensor described in Patent Document 1 has a circular driving mass, an anchor placed at the center of the mass, an elastic anchor element connecting the driving mass and the anchor, and a substrate 2 to which the anchor is fixed, and is configured to detect angular velocity around each axis while the driving mass is rotationally vibrating. However, with this configuration, vibrations of the driving mass are transmitted to the substrate 2 via the elastic anchor element and the anchor, resulting in vibration leakage. This vibration leakage reduces the Q value of the sensor's vibrations (i.e., causes energy loss). A reduced Q value of the vibrations makes it impossible to obtain the desired vibration amplitude, degrading the sensor's detection sensitivity. Furthermore, a driver with high driving capabilities is required to obtain the required amplitude, which leads to an increase in the sensor size. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-271611 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a small physical quantity sensor having a high Q value and high detection sensitivity, and an electronic device using the same. [Means for solving the problem]

[0006] Such an object can be achieved by the present invention described below. In the physical quantity sensor of the present invention, when two axes that are orthogonal to each other are defined as a first axis and a second axis, a ring portion capable of circular vibration; Four support portions that support the ring portion; four beams connecting each of the support portions to a node of the circular vibration of the ring portion; a pair of first mass portions each having a movable portion and disposed opposite to each other in a direction parallel to the first axis via the ring portion; a pair of second mass portions each having a movable portion and disposed opposite to each other in a direction parallel to the second axis via the ring portion; a pair of first spring portions connecting each of the first mass portions to the ring portion so that each of the first mass portions can vibrate relative to the ring portion in a direction parallel to the first axis; a pair of second spring portions connecting each of the second mass portions to the ring portion so that each of the second mass portions can vibrate relative to the ring portion in a direction parallel to the second axis; a vibration means for vibrating at least one of the pair of first mass portions and the pair of second mass portions in a plane direction including the first axis and the second axis at a first frequency in opposite phases to each other; at least one transducer that converts the displacement of the movable portion of each of the first masses and the movable portion of each of the second masses into an electric signal; The ring portion is characterized by vibrating circularly in a direction parallel to the first axis and a direction parallel to the second axis in accordance with the first frequency. This makes it possible to provide a small physical quantity sensor with a high Q value and high detection sensitivity.

[0007] In the physical quantity sensor of the present invention, when two axes that are orthogonal to each other are defined as a first axis and a second axis, a ring portion capable of circular vibration; Four support portions that support the ring portion; four beams connecting each of the support portions to four fixed points that serve as nodes of the circular vibration of the ring portion; a pair of first mass portions each having a first movable portion displaceable around an axis parallel to the second axis and a second movable portion displaceable in a direction parallel to the second axis, the first mass portions being disposed opposite each other in a direction parallel to the first axis via the ring portion; a pair of second mass portions having a third movable portion displaceable around an axis parallel to the first axis and a fourth movable portion displaceable in a direction parallel to the first axis, the second mass portions being disposed opposite each other in a direction parallel to the second axis via the ring portion; a pair of first spring portions connecting each of the first mass portions to the ring so that each of the first mass portions can vibrate relative to the ring portion in a direction parallel to the first axis; a pair of second spring portions connecting each of the second mass portions to the ring so that each of the second mass portions can vibrate relative to the ring in a direction parallel to the second axis; a vibration means for vibrating at least one of the pair of first mass portions and the pair of second mass portions in a plane direction including the first axis and the second axis at a first frequency in opposite phases to each other; a transducer that converts the displacement of a first movable portion of each of the first mass portions and a third movable portion of each of the second mass portions into an electric signal; a transducer that converts the displacement of the second movable portion of each of the first mass portions and the fourth movable portion of each of the second mass portions into an electric signal; The ring portion is characterized by vibrating circularly in a direction parallel to the first axis and a direction parallel to the second axis in accordance with the first frequency. This makes it possible to provide a small physical quantity sensor with a high Q value and high detection sensitivity.

[0008] The physical quantity sensor of the present invention includes a substrate supporting the ring portion, The substrate is preferably a semiconductor substrate, an insulating substrate, or a composite substrate in which a semiconductor layer and an insulating layer are laminated. This simplifies the device configuration. In the physical quantity sensor of the present invention, it is preferable that the ring portion has an outer diameter and an inner diameter, a space is formed inside the inner diameter, and the ring portion is elastically deformable. This allows the ring portion to be more efficiently subjected to circular vibration.

[0009] In the physical quantity sensor of the present invention, the first spring portions are restricted in deformation in a direction parallel to the second axis and in a direction parallel to an axis perpendicular to the first axis and the second axis, It is preferable that the second spring portions are restricted from deformation in a direction parallel to the first axis and in a direction parallel to an axis perpendicular to the first axis and the second axis. This allows the first mass to be stably vibrated in a direction parallel to the first axis, and the second mass to be stably vibrated in a direction parallel to the second axis.

[0010] In the physical quantity sensor of the present invention, it is preferable that the four support parts are located inside the pair of first mass parts and the pair of second mass parts and outside the ring part, and are arranged in positions that are mirror-symmetrical with respect to the first axis and the second axis that intersect with the center of the ring part. This allows the device to be made smaller, and also allows the ring portion to be stably supported.

[0011] In the physical quantity sensor of the present invention, it is preferable that displacement of each of the beams in a radial direction from the center of the ring is restricted. This makes it possible to more effectively prevent or suppress vibration leakage. In the physical quantity sensor of the present invention, it is preferable that the vibration means is either electrostatically driven or piezoelectrically driven. This makes it possible to efficiently vibrate the first mass portion and the second mass portion.

[0012] In the physical quantity sensor of the present invention, it is preferable that the transducer has any one of electrostatic, piezoelectric, and piezo-resistive detection capabilities. This results in a physical quantity sensor with excellent detection capabilities. In the physical quantity sensor of the present invention, it is preferable that the transducer detects an angular velocity around the first axis, an angular velocity around the second axis, and an angular velocity around a third axis perpendicular to both the first axis and the second axis. This allows it to be used as an angular velocity sensor.

[0013] In the physical quantity sensor of the present invention, it is preferable that each of the transducers be paired with another of the transducers, thereby electrically canceling out linear acceleration in a predetermined direction. This improves the accuracy of detecting the angular velocity. In the physical quantity sensor of the present invention, it is preferable that each of the transducers has a unique resonant frequency. This allows driving in a resonant mode, which further improves the accuracy of detecting angular velocity.

[0014] In the physical quantity sensor of the present invention, it is preferable that the circular vibration of the ring portion is a vibration that repeats a state of contracting in a direction parallel to the first axis while expanding in a direction parallel to the second axis, and a state of expanding in a direction parallel to the first axis while contracting in a direction parallel to the second axis. In the physical quantity sensor of the present invention, it is preferable that the first spring portions and the second spring portions are connected to portions of the ring portion inclined at 45 degrees from both the first axis and the second axis. This effectively prevents or suppresses the circular vibration of the ring portion from leaking to the outside.

[0015] The physical quantity sensor of the present invention is characterized in that the projected outer shape of the assembly of the pair of first mass portions and the pair of second mass portions is substantially circular. This allows the device to be made smaller. The physical quantity sensor of the present invention is characterized in that the projected outer shape of the assembly of the pair of first mass portions and the pair of second mass portions is substantially rectangular. This allows the device to be made smaller.

[0016] In the physical quantity sensor of the present invention, it is preferable that the vibration means is connected to the inside of each of the first mass portions and each of the second mass portions. This allows the device to be made smaller. In the physical quantity sensor of the present invention, it is preferable that the transducer is connected to the inside of each of the first mass portions and each of the second mass portions. This allows the device to be made smaller.

[0017] In the physical quantity sensor of the present invention, when two axes that are orthogonal to each other are defined as a first axis and a second axis, An expandable connecting portion; four support parts provided at positions inclined at a predetermined angle from both the first axis and the second axis intersecting with the center of the connecting part of the connecting part, and supporting the connecting part; four beams connecting each of the support portions to the connecting portion; a pair of first mass portions each having a movable portion and disposed opposite to each other in a direction parallel to the first axis via the ring portion; a pair of second mass portions each having a movable portion and disposed opposite to each other in a direction parallel to the second axis via the ring portion; a pair of first spring portions connecting each of the first mass portions to the ring portion so that each of the first mass portions can vibrate relative to the ring portion in a direction parallel to the first axis; a pair of second spring portions connecting each of the second mass portions to the ring portion so that each of the second mass portions can vibrate relative to the ring portion in a direction parallel to the second axis; a vibration means for vibrating at least one of the pair of first mass portions and the pair of second mass portions in a plane direction including the first axis and the second axis at a first frequency in opposite phases to each other; at least one transducer that converts the displacement of the movable portion of each of the first masses and the movable portion of each of the second masses into an electric signal; When the connecting portion expands and contracts in response to the first frequency, the connection portion between the beam and the connecting portion becomes a node. This makes it possible to provide a small physical quantity sensor with a high Q value and high detection sensitivity. The electronic device of the present invention is characterized by using the physical quantity sensor of the present invention. This makes it possible to provide a highly reliable electronic device. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic plan view showing a first embodiment of a physical quantity sensor of the present invention. [Figure 2] FIG. 2 is a detailed plan view of the physical quantity sensor shown in FIG. [Figure 3] 3 is a plan view for explaining vibration of a ring portion of the physical quantity sensor shown in FIG. 2. FIG. [Figure 4] 3 is a plan view for explaining the configuration of a detection means included in the physical quantity sensor shown in FIG. 2. FIG. [Figure 5] FIG. 10 is a diagram for explaining driving of a physical quantity sensor. [Figure 6] FIG. 10 is a diagram for explaining driving of a physical quantity sensor. [Figure 7] FIG. 10 is a diagram for explaining driving of a physical quantity sensor. [Figure 8] FIG. 2 is a plan view showing a second embodiment of a physical quantity sensor according to the present invention. [Figure 9] FIG. 10 is a plan view showing a third embodiment of the physical quantity sensor of the present invention. [Figure 10] FIG. 10 is a plan view showing a fourth embodiment of the physical quantity sensor of the present invention. [Figure 11] FIG. 10 is a plan view showing a fifth embodiment of the physical quantity sensor of the present invention. [Figure 12] FIG. 10 is a plan view showing a sixth embodiment of the physical quantity sensor of the present invention. [Figure 13] FIG. 10 is a plan view showing a seventh embodiment of the physical quantity sensor of the present invention. [Figure 14] FIG. 13 is a plan view showing an eighth embodiment of the physical quantity sensor of the present invention. [Figure 15] 1 is an electronic device (notebook personal computer) equipped with a physical quantity sensor of the present invention. [Figure 16] 1 is an electronic device (mobile phone) equipped with a physical quantity sensor of the present invention. [Figure 17] 1 is an electronic device (digital still camera) equipped with a physical quantity sensor of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A physical quantity sensor according to the present invention will now be described in detail with reference to preferred embodiments shown in the accompanying drawings. First Embodiment FIG. 1 is a schematic plan view showing a first embodiment of a physical quantity sensor of the present invention, FIG. 2 is a detailed plan view of the physical quantity sensor shown in FIG. 1, FIG. 3 is a plan view illustrating vibration of a ring portion of the physical quantity sensor shown in FIG. 2, FIG. 4 is a plan view illustrating the configuration of a detection means of the physical quantity sensor shown in FIG. 2, and FIGS. 5, 6, and 7 are diagrams illustrating the driving of the physical quantity sensor. For ease of explanation, each figure illustrates an X-axis, a Y-axis, and a Z-axis as three mutually orthogonal axes. In the following, the direction parallel to the X-axis (first axis) will be referred to as the "X-axis direction," the direction parallel to the Y-axis (second axis) will be referred to as the Y-axis direction, and the direction parallel to the Z-axis (third axis) will be referred to as the "Z-axis direction."

[0020] 1. Physical quantity sensors The physical quantity sensor 1 of this embodiment is an angular velocity sensor that can detect angular velocities around the X axis, the Y axis, and the Z axis. Such an angular velocity sensor can independently detect angular velocities around the three axes with a single sensor, thereby providing excellent convenience.

[0021] As shown in FIG. 1, the physical quantity sensor 1 includes a ring portion 31 capable of circular vibration, four substrate fixing portions (supporting portions) 61, 62, 63, 64 that support the ring portion 31, four beams 71, 72, 73, 74 that connect the substrate fixing portions 61, 62, 63, 64 to nodes of the circular vibration of the ring portion 31, a pair of first vibration portions (first mass portions) 51, 52 that have movable portions and are arranged opposite each other in the X-axis direction with the ring portion 31 interposed therebetween, and a pair of first vibration portions (first mass portions) 51, 52 that have movable portions and are arranged opposite each other in the Y-axis direction with the ring portion 31 interposed therebetween. The ring portion 31 further includes a pair of second vibrating parts (second mass parts) 53, 54 placed on the ring portion 31, a pair of first inner spring parts (first spring parts) 81, 82 connecting the first vibrating parts 51, 52 and the ring portion 31 so that the first vibrating parts 51, 52 can vibrate in the X-axis direction relative to the ring portion 31, and a pair of second inner spring parts (second spring parts) 83, 84 connecting the second vibrating parts 53, 54 and the ring portion 31 so that the second vibrating parts 53, 54 can vibrate in a direction parallel to the Y-axis relative to the ring portion 31. The ring portion 31 further includes a vibration means 4 that vibrates the first vibrating parts 51, 52 in the X-axis direction at a first frequency and in opposite phases to each other, and a transducer (detection means 9) that converts the displacement of the movable parts included in the first vibrating parts 51, 52 and the movable parts included in the second vibrating parts 53, 54 into electrical signals. The ring portion 31 vibrates circularly in the X-axis direction and the Y-axis direction in accordance with the first frequency. With such a physical quantity sensor 1, the vibration of the ring portion 31 does not leak to the substrate, so the Q value of the vibration can be increased while miniaturizing the device. Therefore, a small physical quantity sensor with excellent detection accuracy can be provided.

[0022] The physical quantity sensor 1 will be described in detail below. As shown in Figure 2, the physical quantity sensor 1 has a vibration system structure 3 arranged in the XY plane, a substrate 2 that supports the vibration system structure 3, a vibration means 4 that vibrates the vibration system structure 3, and a detection means 9 that detects the angular velocity applied to the physical quantity sensor 1. -Vibration system structure- As shown in FIG. 2 , the vibration system structure 3 includes a ring portion (connecting portion) 31, a pair of first vibration portions (first mass portions) 51, 52 arranged opposite each other in the X-axis direction via the ring portion 31, first inner spring portions (first spring portions) 81, 82 connecting the first vibration portions 51, 52 and the ring portion 31, a pair of second vibration portions (second mass portions) 53, 54 arranged opposite each other in the Y-axis direction via the ring portion 31, second inner spring portions (second spring portions) 83, 84 connecting the second vibration portions 53, 54 and the ring portion 31, and an inner fixing spring 81, 82 provided around the ring portion 31. The vibration unit 51 is made up of support parts (support portions) 61, 62, 63, 64, beams 71, 72, 73, 74 connecting the ring part 31 and the inner fixed parts 61, 62, 63, 64, outer fixed parts 651, 652, 661, 662, 671, 672, 681, 682 provided on the outside of the vibration parts 51, 52, 53, 54, and outer spring parts 851, 852, 861, 862, 871, 872, 881, 882 connecting the vibration parts 51, 52, 53, 54 and the outer fixed parts 651, 652, 661, 662, 671, 672, 681, 682.

[0023] The vibration system structure 3 of this embodiment is mainly made of silicon, and the above-mentioned components are integrally formed on a silicon substrate (silicon wafer) by processing it into a desired outer shape using thin film formation techniques (e.g., deposition techniques such as epitaxial growth and chemical vapor deposition) and various processing techniques (e.g., etching techniques such as dry etching and wet etching). Alternatively, the above-mentioned components can be formed by bonding a silicon substrate and a glass substrate together, and then processing only the silicon substrate into a desired outer shape.

[0024] By using silicon as at least the main material of the vibration system structure 3, it is possible to achieve excellent vibration characteristics and to exhibit excellent durability. Furthermore, it becomes possible to apply the fine processing technology used in manufacturing silicon semiconductor devices, thereby enabling the physical quantity sensor 1 to be miniaturized. Furthermore, by using silicon as the main material of the vibration system structure 3, as will be described later, the physical quantity sensor 1 can be driven without forming electrodes on the vibration system structure 3, thereby simplifying the structure of the device. Even if a material other than silicon, such as an insulator, is used, it is possible to form the vibration system structure of the present invention by coating the outer periphery of the material with a metal film.

[0025] The main material of the substrate 2 is not limited to silicon, but may be, for example, quartz crystal or various types of glass. In the vibration system structure 3 of this embodiment, the projected outer shape of the assembly of the vibration parts 51, 52, 53, and 54 is substantially circular in a plan view normal to the Z-axis direction, which allows the physical quantity sensor 1 to be made smaller.

[0026] (Ring part) The ring portion 31 has an annular shape with an outer diameter and an inner diameter that are concentric circles, and has a structure in which there is no structure inside the inner diameter. Note that, hereinafter, the center of the ring portion 31 will be referred to as "center O." Furthermore, ring portion 31 is disposed so that its axis is parallel to the Z axis. This ring portion 31 is elastically deformable, and as shown in Fig. 3, it deforms between a first state in which it contracts in the X-axis direction and expands in the Y-axis direction, and a second state in which it expands in the X-axis direction and contracts in the Y-axis direction, due to vibration of first vibration portions 51, 52 by vibration means 4. Note that, hereinafter, vibration that alternates between the first state and the second state is also referred to as "circular vibration."

[0027] (First vibration part) First vibrating part 51 is plate-shaped and includes frame part 511 that forms the edge of first vibrating part 51, Z-axis displacement part (first movable part, movable part) 512 connected to frame part 511 via shaft parts 513 and 514, comb-tooth shaped drive electrode 515, and Y-axis displacement part (second movable part, movable part) 516 connected to the frame via spring part 517.

[0028] Similarly, first vibrating part 52 is also plate-shaped. First vibrating part 52 is also made up of frame part 521 that forms the edge of first vibrating part 52, Z-axis displacement part (first movable part, movable part) 522 connected to frame part 521 via shaft parts 523 and 524, comb-tooth shaped drive electrode 525, and Y-axis displacement part (second movable part, movable part) 526 connected to the frame via spring part 527.

[0029] The first vibrating parts 51 and 52 will be described in detail below, but since the first vibrating parts 51 and 52 have the same configuration, the first vibrating part 51 will be described below as a representative, and the description of the first vibrating part 52 will be omitted. The outer shape of the frame portion 511 is a substantially 90-degree sector in a plan view with the Z axis as the normal line. The frame portion 511 is formed with a pair of first openings 511a, a pair of second openings 511b, and a third opening 511c.

[0030] A plurality of comb-shaped driving electrodes 515 are arranged in each first opening 511a. Each driving electrode 515 extends in the Y-axis direction and is spaced apart from each other in the X-axis direction. The driving electrodes 515 constitute a part of the vibration means 4. A Y-axis direction displacement portion 516 is provided inside each second opening 511b. The Y-axis direction displacement portion 516 is composed of a frame portion 516a and a plurality of detection electrodes 516b provided inside the frame portion 516a. The detection electrodes 516b extend in the X-axis direction and are provided spaced apart from each other in the Y-axis direction.

[0031] Each Y-axis direction displacement portion 516 is connected to the frame portion 511 by four spring portions 517. Each spring portion 517 is shaped to extend in the Y-axis direction while reciprocating in the X-axis direction. By shaping each spring portion 517 in this way, the spring portion 517 can be made to expand and contract smoothly in the Y-axis direction, and deformation of the spring portion 517 in directions other than the Y-axis direction (i.e., the X-axis direction and the Z-axis direction) can be effectively prevented or suppressed. Therefore, each Y-axis direction displacement portion 516 can be smoothly displaced in the Y-axis direction.

[0032] A Z-axis direction displacement part 512 is provided inside the third opening 511c. The Z-axis direction displacement part 512 is connected to the frame part 511 by shaft parts 513 and 514. The shaft parts 513 and 514 extend in the Y-axis direction and are provided coaxially. Therefore, when stress in the Z-axis direction is applied to the physical quantity sensor 1, the Z-axis direction displacement part 512 rotates around the shaft parts 513 and 514 while torsionally deforming the shaft parts 513 and 514 around their axes. The above has described first vibrating section 51. As described above, first vibrating section 52 has the same configuration as first vibrating section 51, and is provided symmetrically with respect to the Y axis that intersects with center O of ring section 31 in a plan view with the Z axis as the normal line. However, a requirement of the present invention is a configuration that minimizes vibration leakage to substrate 2, and the components do not need to be completely symmetrical with respect to center O or the Y axis.

[0033] (Second vibration part) Second vibrating section 53 is plate-shaped and includes frame section 531 that forms the edge of second vibrating section 53, Z-axis displacement section (third movable section, movable section) 532 that is connected to frame section 531 via shaft sections 533 and 534, and X-axis displacement section (fourth movable section, movable section) 536 that is connected to the frame via spring section 537. Similarly, second vibrating part 54 is also plate-shaped. Second vibrating part 54 is also made up of frame part 541 that forms the edge of second vibrating part 54, Z-axis displacement part (third movable part, movable part) 542 connected to frame part 541 via shaft parts 543 and 544, and X-axis displacement part (fourth movable part, movable part) 546 connected to the frame via spring part 547.

[0034] The second vibrating parts 53 and 54 will be described in detail below, but since the second vibrating parts 53 and 54 have the same configuration, the second vibrating part 53 will be described below as a representative, and the description of the second vibrating part 54 will be omitted. The outer shape of frame portion 531 is a substantially 90-degree sector in a plan view with the Z axis as the normal line. The outer shape of frame portion 531 is the same as that of frame portions 511 and 521 of first vibrating portions 51 and 52. Frame portion 531 is formed with a pair of second openings 531b and a third opening 531c.

[0035] An X-axis displacement portion 536 is provided inside each second opening 511b. X-axis displacement portion 536 is composed of a frame portion 536a and a plurality of detection electrodes 536b provided inside frame portion 536a. Detection electrodes 536b extend in the Y-axis direction and are spaced apart from each other in the X-axis direction. Such X-axis direction displacement portion 536 is connected to frame portion 531 by four spring portions 537. Each spring portion 537 has a shape that extends in the X-axis direction while reciprocating in the Y-axis direction. By giving each spring portion 537 such a shape, spring portion 537 can be made to expand and contract smoothly in the X-axis direction, and deformation of spring portion 537 in directions other than the X-axis direction (i.e., the Y-axis direction and the Z-axis direction) can be effectively prevented or suppressed. Therefore, X-axis direction displacement portion 536 can be smoothly displaced in the X-axis direction.

[0036] A Z-axis direction displacement part 532 is provided inside the third opening 531c. The Z-axis direction displacement part 532 is connected to the frame part 531 by shaft parts 533 and 534. The shaft parts 533 and 534 extend in the X-axis direction and are provided coaxially. Therefore, when stress in the Z-axis direction is applied to the physical quantity sensor 1, the Z-axis direction displacement part 532 rotates around the shaft parts 533 and 534 while torsionally deforming the shaft parts 533 and 534 around their axes. The above has described second vibrating part 53. As described above, second vibrating part 54 has the same configuration as second vibrating part 53, and is provided symmetrically with respect to the X axis that intersects with center O of ring part 31 in a plan view with the Z axis as the normal line. However, as described above, second vibrating parts 53 and 54 do not need to be completely symmetrical with respect to center O or the X axis.

[0037] (First inner spring part) The first inner spring portion 81 connects the first vibrating portion 51 and the ring portion 31. The first inner spring portion 82 connects the first vibrating portion 52 and the ring portion 31. Since the first inner spring portions 81 and 82 have the same configuration, the following description will mainly focus on the first inner spring portion 81, and the description of the first inner spring portion 82 will be omitted.

[0038] The first inner spring portion 81 is composed of a pair of spring portions 811, 812, each of which has a shape that extends in the X-axis direction while reciprocating in the Y-axis direction. Furthermore, the spring portions 811, 812 are provided symmetrically with respect to the X-axis that intersects with the center O of the ring portion 31 in a plan view with the Z-axis as the normal. By forming the spring portions 811, 812 in this shape, the first inner spring portion 81 can smoothly expand and contract in the X-axis direction while suppressing (restricting) deformation in the Y-axis and Z-axis directions. Therefore, as described below, the first vibrating portion 51 can smoothly vibrate in the X-axis direction while expanding and contracting the first inner spring portion 81 in the X-axis direction.

[0039] (Second inner spring part) The second inner spring portion 83 connects the second vibrating portion 53 and the ring portion 31. The second inner spring portion 84 connects the second vibrating portion 54 and the ring portion 31. Since the second inner spring portions 83, 84 have the same configuration, the second inner spring portion 83 will be described below as a representative, and a description of the first inner spring portion 84 will be omitted.

[0040] The second inner spring portion 83 is composed of a pair of spring portions 831, 832, each of which has a shape that reciprocates in the X-axis direction and extends in the Y-axis direction. Furthermore, the spring portions 831, 832 are provided symmetrically with respect to the Y-axis that intersects with the center O of the ring portion 31 in a plan view normalized to the Z-axis. By configuring the second inner spring portion 83 in this manner, the second inner spring portion 83 can smoothly expand and contract in the Y-axis direction while suppressing (restricting) deformation in the X-axis and Z-axis directions. Therefore, as described below, the second inner spring portion 83 can expand and contract in the Y-axis direction while smoothly vibrating the second vibrating portion 53 in the Y-axis direction.

[0041] (Inner fixed part) The inner fixing portions 61, 62, 63, and 64 have the function of supporting the ring portion 31. These inner fixing portions 61, 62, 63, and 64 are provided inside the four vibrating portions 51, 52, 53, and 54, respectively. By arranging the inner fixing portions 61, 62, 63, and 64 in this manner, space can be effectively utilized, and the physical quantity sensor 1 can be made more compact. In addition, the lengths of the beams 71, 72, 73, and 74 can be shortened, so the ring portion 31 can be supported more stably. Furthermore, by arranging the inner fixing portions 61, 62, 63, and 64 in this manner, they can serve as stoppers for the first vibrating portions 51 and 52 and the second vibrating portions 53 and 54.

[0042] In a plan view normal to the Z axis, the inner fixing portions 61, 62, 63, and 64 are provided at 90-degree intervals around the outer periphery of the ring portion 31. Specifically, when a pair of axes J1 and J2 are defined as J1 and J2 that intersect with the center O of the ring portion 31 and are inclined at 45 degrees with respect to the X and Y axes, respectively, in a plan view normal to the Z axis, the inner fixing portions 61 and 63 are located on the axis J1 and are arranged opposite each other with the ring portion 31 interposed therebetween. Furthermore, the inner fixing portions 62 and 64 are located on the axis J2 and are arranged opposite each other with the ring portion 31 interposed therebetween. In other words, the four inner fixing portions 61, 62, 63, 64 are provided at positions that are mirror symmetrical with respect to both the X-axis and the Y-axis, thereby enabling the ring portion 31 to be stably supported.

[0043] (beam) The beams 71, 72, 73, and 74 connect the ring portion 31 and the inner fixed portions 61, 62, 63, and 64. The beam 71 extends linearly along the axis J1 and connects the ring portion 31 and the inner fixed portion 61. Similarly, the beam 72 extends linearly along the axis J2 and connects the ring portion 31 and the inner fixed portion 62. Furthermore, the beam 73 extends linearly along the axis J1 and connects the ring portion 31 and the inner fixed portion 63. Furthermore, the beam 74 extends linearly along the axis J2 and connects the ring portion 31 and the inner fixed portion 64.

[0044] The beams 71, 72, 73, and 74 are connected to respective portions (fixed points, first group fixed points) inclined at 45 degrees with respect to the X-axis and Y-axis on the side surface of the ring portion 31. As shown in FIG. 3, these fixed points are portions that serve as nodes of the circular vibration of the ring portion 31 (i.e., portions where substantial displacement and deformation do not occur). By connecting the beams 71, 72, 73, and 74 to these respective fixed points, the beams 71, 72, 73, and 74 do not impede the circular vibration of the ring portion 31, and prevent or suppress vibrations caused by the circular vibration from leaking to the outside of the vibration system structure 3 via the beams 71, 72, 73, and 74 and the fixed portions 61, 62, 63, and 64. As a result, the Q value of the vibration of the vibration system structure 3 increases, and the detection accuracy of the physical quantity sensor 1 improves. Furthermore, since the vibration system structure 3 can be vibrated efficiently, the output of the vibration means 4 can be reduced, thereby enabling the physical quantity sensor 1 to be made more compact. Furthermore, the beams 71, 72, 73, and 74 are restricted from moving (deforming) in the radial direction (extension direction) relative to the center O of the ring portion 31. This allows the inner fixing portions 61, 62, 63, and 64 to more stably support the ring portion 31, and also makes it possible to more effectively prevent or suppress vibration leakage.

[0045] (Outside fixed part) Outer fixed portions 651, 652, 661, 662, 671, 672, 681, and 682 are provided outside the four vibrating portions 51, 52, 53, and 54, respectively. Outer fixed portions 651 and 652 are provided corresponding to first vibrating portion 51 and are spaced apart from each other in the Y-axis direction. Similarly, outer fixed portions 661 and 662 are provided corresponding to first vibrating portion 52 and are spaced apart from each other in the Y-axis direction. Outer fixed portions 671 and 672 are provided corresponding to second vibrating portion 53 and are spaced apart from each other in the X-axis direction. Outer fixed portions 681 and 682 are provided corresponding to second vibrating portion 54 and are spaced apart from each other in the X-axis direction.

[0046] (Outer spring part) The outer spring portions 851, 852, 861, 862, 871, 872, 881, and 882 connect the outer fixed portions 651, 652, 661, 662, 671, 672, 681, and 682 to the vibrating portions 51, 52, 53, and 54. Specifically, the outer spring portions 851 and 852 connect the first vibrating portion 51 to the outer fixed portions 651 and 652, the outer spring portions 861 and 862 connect the first vibrating portion 52 to the outer fixed portions 661 and 656, the outer spring portions 871 and 872 connect the second vibrating portion 53 to the outer fixed portions 671 and 672, and the outer spring portions 881 and 882 connect the second vibrating portion 54 to the outer fixed portions 681 and 682.

[0047] The outer spring portions 851 and 852 are shaped to extend in the X-axis direction while reciprocating in the Y-axis direction. The outer spring portions 851 and 852 are provided symmetrically with respect to the X-axis that intersects with the center O of the ring portion 31. Similarly, the outer spring portions 861 and 862 extend in the X-axis direction while reciprocating in the Y-axis direction. The outer spring portions 861 and 862 are provided symmetrically with respect to the X-axis that intersects with the center O of the ring portion 31. The outer spring portions 871 and 872 are shaped to extend in the Y-axis direction while reciprocating in the X-axis direction. The outer spring portions 871 and 872 are provided symmetrically with respect to the Y-axis that intersects with the center O of the ring portion 31.

[0048] Similarly, outer spring portions 881 and 882 are shaped to extend in the Y-axis direction while reciprocating in the X-axis direction. Furthermore, outer spring portions 881 and 882 are provided symmetrically with respect to the Y-axis that intersects with the center O of ring portion 31. However, it is not an essential condition of the present invention that outer spring portions 851 and 852, 861 and 862, 871 and 872, and 881 and 882 be completely symmetrical with respect to the center O, the X-axis, or the Y-axis. The vibration system structure 3 as described above has a natural resonance frequency, which allows the vibration system structure 3 to be driven in a resonance mode, as will be described later, thereby improving the accuracy of detecting angular velocity.

[0049] -substrate- The substrate 2 supports the vibration system structure 3. As shown in Fig. 2, the substrate 2 is plate-shaped and is provided in the XY plane. Then, inner fixing portions 61, 62, 63, 64 and outer fixing portions 651, 652, 661, 662, 671, 672, 681, 682 of the vibration system structure 3 are joined to the upper surface of the substrate 2, whereby the vibration system structure 3 is fixed to and supported by the substrate 2.

[0050] The method of joining the substrate 2 to the inner fixing portions 61, 62, 63, 64 and the outer fixing portions 651, 652, 661, 662, 671, 672, 681, 682 is not particularly limited, and various joining methods such as direct bonding and anodic bonding may be used for joining, or depending on the constituent materials of the vibration system structure 3 and the substrate 2, joining may be performed using a support member such as an adhesive. Furthermore, a recess is formed as needed on the upper surface (the surface facing the vibration system 3) of the substrate 2. This recess has the function of preventing contact between the substrate 2 and the parts of the vibration system 3 that actually vibrate (for example, the first vibrating parts 51 and 52 and the second vibrating parts 53 and 54). Such a substrate 2 is formed by processing, for example, a semiconductor substrate such as silicon, an insulating substrate such as glass or quartz, or a composite substrate formed by laminating semiconductor and insulating layers into a desired outer shape using various processing techniques, which simplifies the configuration of the physical quantity sensor 1.

[0051] -Vibration means- The vibration means 4 has a function of vibrating the first vibration parts 51, 52 in the X-axis direction in opposite phases at a predetermined frequency (first frequency). That is, the vibration means 4 vibrates the first vibration parts 51, 52 so as to alternate between displacing the first vibration parts 51, 52 in a direction approaching the ring part 31 (inward) and displacing the first vibration parts 51, 52 in a direction moving away from the ring part 31 (outward).

[0052] The vibration means 4 has a plurality of fixed electrodes 41 provided corresponding to the drive electrodes 515 of the first vibration section 51. Each fixed electrode 41 has a pair of comb-like electrode pieces 411, 412 arranged opposite each other in the X-axis direction with the drive electrode 515 interposed therebetween. Similarly, the vibration means 4 has a plurality of fixed electrodes 42 provided corresponding to each drive electrode 525 of the first vibration section 52. Each fixed electrode 42 has a pair of comb-like electrode pieces 421, 422 arranged opposite each other in the X-axis direction with the drive electrode 525 interposed therebetween.

[0053] The vibration means 4 applies alternating voltages with a phase difference of 180 degrees to each electrode piece 411, 421 and each electrode piece 412, 422 using a power source not shown, thereby generating electrostatic forces between each drive electrode 515, 525 and each electrode piece 411, 421, and between each drive electrode 515, 525 and each electrode piece 412, 422, and causing the first inner spring portions 81, 82 and outer spring portions 851, 852, 861, 862 to expand and contract in the X-axis direction, while the first vibration portions 51, 52 vibrate in the X-axis direction in opposite phases to each other and at a predetermined frequency.

[0054] The frequency of the alternating voltage is not particularly limited, but is preferably approximately equal to the resonance frequency of the vibration system structure 3. This allows the vibration system structure 3 to be driven in a resonance mode, thereby improving the accuracy of detecting angular velocity. When the first vibrating portions 51, 52 vibrate in opposite phases to each other, the vibrations are transmitted through the first inner spring portions 81, 82 to the ring portion 31. Then, when the first vibrating portions 51, 52 are displaced inward, the ring portion 31 deforms so as to contract in the X-axis direction and expand in the Y-axis direction, and when the first vibrating portions 51, 52 are displaced outward, the ring portion 31 deforms so as to expand in the X-axis direction and contract in the Y-axis direction. In other words, the ring portion 31 vibrates circularly in synchronization with the vibrations of the first vibrating portions 51, 52.

[0055] Furthermore, when the ring portion 31 deforms due to the circular vibration so as to contract in the X-axis direction and expand in the Y-axis direction, the second vibrating portions 53 and 54 are both displaced outward due to the deformation, and conversely, when the ring portion 31 deforms so as to expand in the X-axis direction and contract in the Y-axis direction, the second vibrating portions 53 and 54 are both displaced inward. In other words, in synchronization with the circular vibration of the ring portion 31, the second vibrating portions 53 and 54 vibrate in the Y-axis direction in opposite phases to each other.

[0056] That is, in the physical quantity sensor 1, by utilizing the circular vibration of the ring portion 31, the vibration portions 51, 52, 53, 54 can be vibrated so that a state in which the first vibration portions 515, 52 are displaced inward while the second vibration portions 53, 54 are displaced outward, and a state in which the first vibration portions 51, 52 are displaced outward while the second vibration portions 53, 54 are displaced inward are repeated.

[0057] The fixed points to which the beams 71, 72, 73, and 74 of the ring portion 31 are connected are nodes of the circular vibration of the ring portion 31 (i.e., locations where no substantial displacement or deformation occurs). Therefore, the beams 71, 72, 73, and 74 do not impede the circular vibration of the ring portion 31, and vibrations caused by the circular vibration are prevented or suppressed from leaking to the outside of the vibration system structure 3 via the beams 71, 72, 73, and 74 and the fixed portions 61, 62, 63, and 64. As a result, the Q value of the vibration of the vibration system structure 3 increases, and the detection accuracy of the physical quantity sensor 1 improves. Furthermore, because the vibration system structure 3 can be vibrated efficiently, the output of the vibration means 4 can be reduced, and as a result, the physical quantity sensor 1 can be made more compact. Furthermore, electrostatic driving as in this embodiment makes it possible to generate the above-described vibrations more smoothly and reliably. Furthermore, in this embodiment, since the vibration means 4 is connected to the inside of each of the vibration parts 51, 52, 53, and 54, space can be used effectively, and the physical quantity sensor 1 can be made smaller.

[0058] -Detection Method 9- As shown in Fig. 4, the detection means 9 has displacement transducers 91, 92, 93, and 94, and rotation transducers 95, 96, 97, and 98. For ease of explanation, some of the components of the physical quantity sensor 1 are not shown in Fig. 4. The displacement transducer 91 has a Y-axis direction displacement portion 516 provided on the first vibrating portion 51, and a fixed electrode 911 fixed to the substrate 2 via an anchor. A plurality of fixed electrodes 911 are provided corresponding to the detection electrodes 516b of the Y-axis direction displacement portion 516. Each fixed electrode 911 has a pair of electrode pieces 911a, 911b arranged opposite each other with the detection electrode 516b interposed therebetween, and these electrode pieces 911a, 911b are provided extending in the X-axis direction.

[0059] The displacement transducer 92 has a Y-axis direction displacement portion 526 provided on the first vibrating portion 52, and a fixed electrode 921 fixed to the substrate 2 via an anchor. A plurality of fixed electrodes 921 are provided corresponding to the detection electrodes 526b of the Y-axis direction displacement portion 526. Each fixed electrode 921 has a pair of electrode pieces 921a, 921b arranged opposite each other with the detection electrode 526b interposed therebetween, and these electrode pieces 921a, 921b are provided extending in the X-axis direction.

[0060] The displacement transducer 93 has an X-axis direction displacement section 536 provided on the second vibration section 53, and a fixed electrode 931 fixed to the substrate 2 via an anchor. A plurality of fixed electrodes 931 are provided corresponding to the detection electrodes 536b of the X-axis direction displacement section 536. Each fixed electrode 931 has a pair of electrode pieces 931a, 931b arranged opposite each other with the detection electrode 536b interposed therebetween, and these electrode pieces 931a, 931b are provided extending in the Y-axis direction.

[0061] The displacement transducer 94 has an X-axis direction displacement section 546 provided on the second vibration section 54, and a fixed electrode 941 fixed to the substrate 2 via an anchor. A plurality of fixed electrodes 941 are provided corresponding to the detection electrodes 546b of the X-axis direction displacement section 546. Each fixed electrode 941 has a pair of electrode pieces 941a, 941b arranged opposite each other with the detection electrode 546b interposed therebetween, and these electrode pieces 941a, 941b are provided extending in the Y-axis direction. In this embodiment, these displacement transducers 91, 92, 93, and 94 are connected to the inside of the vibration parts 51, 52, 53, and 54, so that the space of the device can be used effectively and the physical quantity sensor 1 can be made smaller.

[0062] The rotary transducer 95 has a Z-axis direction displacement part 512 provided on the first vibration part 51 via axes 513 and 514, and a fixed electrode 951 fixed to the substrate 2 and arranged opposite the Z-axis direction displacement part 512 at a distance in the Z-axis direction. The rotary transducer 96 has a Z-axis direction displacement part 522 provided on the first vibration part 52 via axes 523 and 524, and a fixed electrode 961 fixed to the substrate 2 and arranged opposite the Z-axis direction displacement part 522 at a distance in the Z-axis direction.

[0063] The rotary transducer 97 has a Z-axis direction displacement part 532 provided on the second vibration part 53 via axes 533 and 534, and a fixed electrode 971 fixed to the substrate 2 and arranged opposite the Z-axis direction displacement part 532 at a distance in the Z-axis direction. The rotary transducer 98 has a Z-axis direction displacement part 542 provided on the second vibration part 54 via axes 543 and 544, and a fixed electrode 981 fixed to the substrate 2 and arranged opposite the Z-axis direction displacement part 542 at a distance in the Z-axis direction. In this embodiment, these rotary transducers 95, 96, 97, and 98 are connected to the inside of the vibration parts 51, 52, 53, and 54, so that the space of the device can be used effectively and the physical quantity sensor 1 can be made smaller.

[0064] A method for detecting angular velocity using such detection means 9 will be briefly described below with reference to Figures 5, 6, and 7. Note that for the sake of convenience, some of the configuration of the physical quantity sensor 1 is not shown in Figures 5, 6, and 7. -Detecting angular velocity around the Z axis- As shown in Figure 5, when an angular velocity ω around the Z axis is applied to the physical quantity sensor 1 while the vibration means 4 vibrates the first vibrating parts 51 and 52 in the X-axis direction and the second vibrating parts 53 and 54 in the Y-axis direction, a Coriolis force in the Y-axis direction acts on the first vibrating parts 51 and 52 vibrating in the X-axis direction, and a Coriolis force in the X-axis direction acts on the second vibrating parts 53 and 54 vibrating in the Y-axis direction.

[0065] When such a Coriolis force acts, in the first vibrating unit 51, the Y-axis displacement unit 516 is displaced in the Y-axis direction relative to the frame unit 511, which changes the capacitance between the detection electrode 516b and the electrode piece 911a and the capacitance between the detection electrode 516b and the electrode piece 911b, resulting in a difference between these capacitances. Similarly, in the first vibrating unit 52, the Y-axis displacement unit 526 is displaced in the Y-axis direction relative to the frame unit 521, which changes the capacitance between the detection electrode 526b and the electrode piece 921a and the capacitance between the detection electrode 516b and the electrode piece 921b, resulting in a difference between these capacitances.

[0066] Furthermore, in the second vibrating section 53, the X-axis displacement section 536 is displaced in the X-axis direction relative to the frame section 531, which changes the capacitance between the detection electrode 536b and the electrode piece 931a and the capacitance between the detection electrode 536b and the electrode piece 931b, resulting in a difference between these capacitances. Similarly, in the second vibrating section 54, the X-axis displacement section 546 is displaced in the X-axis direction relative to the frame section 541, which changes the capacitance between the detection electrode 546b and the electrode piece 941a and the capacitance between the detection electrode 546b and the electrode piece 941b, resulting in a difference between these capacitances. The detection means 9 detects such changes in electrostatic capacitance that occur in the vibration parts 51, 52, 53, and 54, and can detect the angular velocity around the Z axis that is applied to the physical quantity sensor 1 from the detection results.

[0067] -Detecting angular velocity around the X axis- As shown in the perspective view of FIG. 6, when an angular velocity about the X-axis is applied to the physical quantity sensor 1 while the vibration means 4 vibrates the first vibrating parts 51 and 52 in the X-axis direction and the second vibrating parts 53 and 54 in the Y-axis direction, a Coriolis force in the Z-axis direction acts on the second vibrating parts 53 and 54 vibrating in the Y-axis direction.

[0068] When such a Coriolis force acts, in the second vibrating part 53, the Z-axis displacement part 532 rotates around the shafts 533 and 534, thereby changing the capacitance between the Z-axis displacement part 532 and the fixed electrode 971. Similarly, in the second vibrating part 54, the Z-axis displacement part 542 rotates around the shafts 543 and 544, thereby changing the capacitance between the Z-axis displacement part 542 and the fixed electrode 981. The detection means 9 detects such a change in electrostatic capacitance that occurs in the second vibration portions 53 and 54, and can detect the angular velocity about the X axis that is applied to the physical quantity sensor 1 from the detection result.

[0069] -Detecting angular velocity around the Y axis- As shown in Figure 7, when an angular velocity around the Y axis is applied to the physical quantity sensor 1 while the vibration means 4 vibrates the first vibrating parts 51 and 52 in the X axis direction and the second vibrating parts 53 and 54 in the Y axis direction, a Coriolis force in the Z axis direction acts on the first vibrating parts 51 and 52 vibrating in the X axis direction.

[0070] When such a Coriolis force acts, in the first vibrating part 51, the Z-axis direction displacement part 512 rotates around the shafts 513 and 514, thereby changing the capacitance between the Z-axis direction displacement part 512 and the fixed electrode 951. Similarly, in the first vibrating part 52, the Z-axis direction displacement part 522 rotates around the shafts 523 and 524, thereby changing the capacitance between the Z-axis direction displacement part 522 and the fixed electrode 961.

[0071] The detection means 9 detects such a change in electrostatic capacitance that occurs in the first vibration parts 51 and 52, and can detect the angular velocity about the X axis that is applied to the physical quantity sensor 1 from the detection result. As described above, the physical quantity sensor 1 can detect angular velocities around all of the X-axis, Y-axis, and Z-axis. This results in a small and highly convenient physical quantity sensor 1. Furthermore, in this embodiment, the electrostatic detection means 9 is used, which allows for the device to be made smaller while improving detection accuracy.

[0072] In the physical quantity sensor 1, the displacement transducers 91 and 92 form a pair and have the function of canceling the acceleration in the Y-axis direction (linear acceleration) applied to the physical quantity sensor 1. In addition, the displacement transducers 93 and 94 form a pair and have the function of canceling the acceleration in the X-axis direction applied to the physical quantity sensor 1. In addition, the rotation transducers 95, 96, 97, and 98 form a pair and have the function of canceling the acceleration in the Z-axis direction applied to the physical quantity sensor 1.

[0073] Specifically, for example, when acceleration is applied to the physical quantity sensor 1 in the Y-axis direction, the Y-axis displacement portion 516 of the first vibrating portion 51 and the Y-axis displacement portion 526 of the first vibrating portion 52 are both displaced to the same side in the Y-axis direction. Such displacement of the Y-axis displacement portions 516 and 526 differs from the displacement when an angular velocity about the Z-axis is applied (i.e., the Y-axis displacement portions 516 and 526 are displaced to opposite sides in the Y-axis direction). Therefore, the physical quantity sensor 1 can detect acceleration applied to the physical quantity sensor 1 from changes in the capacitance between the detection electrode 516b and each of the electrode pieces 911a and 911b and between the detection electrode 526b and each of the electrode pieces 921a and 921b. When this angular velocity is detected, the detected acceleration can be electrically canceled by a correction process or the like. As a result, the angular velocity detection accuracy of the physical quantity sensor 1 is further improved. Acceleration in the X-axis direction and acceleration in the Z-axis direction can also be canceled in a similar manner.

[0074] Second Embodiment FIG. 8 is a plan view showing a second embodiment of the physical quantity sensor of the present invention. The physical quantity sensor of this embodiment will be described focusing on the differences from the above-described embodiment, and a description of the same points will be omitted. The physical quantity sensor 1 of this embodiment is similar to the physical quantity sensor of the first embodiment described above, except that the configuration of the vibration means is different. In Fig. 8, the same components as those of the first embodiment described above are denoted by the same reference numerals.

[0075] In the physical quantity sensor 1 of this embodiment, the vibration means 4 is also connected to the second vibration parts 53 and 54. That is, the second vibration part 53 is provided with a plurality of drive electrodes 535 extending in the X-axis direction, and the second vibration part 54 is also provided with a plurality of drive electrodes 545 extending in the X-axis direction. The vibration means 4 also has a plurality of fixed electrodes 43 provided corresponding to the drive electrodes 535 of the second vibration section 53. Each fixed electrode 43 has a pair of comb-shaped electrode pieces 431, 432 arranged opposite to each other in the Y-axis direction with the drive electrode 535 interposed therebetween. Similarly, the vibration means 4 has a plurality of fixed electrodes 44 provided corresponding to each drive electrode 545 of the second vibration section 54. Each fixed electrode 44 has a pair of comb-shaped electrode pieces 441, 442 arranged opposite to each other in the Y-axis direction with the drive electrode 545 interposed therebetween.

[0076] The vibration means 4 applies alternating voltages that are 180 degrees out of phase with each other to the electrode pieces 411, 421, 432, 442 and the electrode pieces 412, 422, 431, 441 using a power source not shown, thereby vibrating the first vibration parts 51, 52 in the X-axis direction in opposite phases to each other, and vibrating the second vibration parts 53, 54 in the Y-axis direction in opposite phases to each other and in the opposite direction to the first vibration parts 51, 52. The second embodiment can also achieve the same effects as the first embodiment described above.

[0077] <Third embodiment> FIG. 9 is a plan view showing a third embodiment of the physical quantity sensor of the present invention. The physical quantity sensor of this embodiment will be described focusing on the differences from the above-described embodiment, and a description of the same points will be omitted. The physical quantity sensor 1 of this embodiment is similar to the physical quantity sensor of the first embodiment described above, except that the projected shape of the vibration system structure is different. In Fig. 9, the same components as those of the first embodiment described above are denoted by the same reference numerals.

[0078] In the physical quantity sensor 1 of this embodiment, the outer shapes of the vibration parts 51, 52, 53, and 54 are each trapezoidal in plan view with the Z axis as the normal line. Furthermore, in plan view with the Z axis direction as the normal line, the projected outer shape of the assembly of the vibration parts 51, 52, 53, and 54 is approximately rectangular. This allows the physical quantity sensor 1 to be made smaller. Furthermore, for example, when the physical quantity sensor 1 is mounted within a chip, the shape corresponds to the shape of the chip, making it easy to mount the physical quantity sensor 1 on the chip. The third embodiment can also achieve the same effects as the first embodiment described above.

[0079] <Fourth embodiment> FIG. 10 is a plan view showing a fourth embodiment of the physical quantity sensor of the present invention. The physical quantity sensor of this embodiment will be described focusing on the differences from the above-described embodiment, and a description of the same points will be omitted. The physical quantity sensor 1 of this embodiment is similar to the physical quantity sensor of the first embodiment described above, except for the configuration of the vibration means. In Fig. 10, the same components as those of the first embodiment described above are denoted by the same reference numerals.

[0080] The vibration means 4 of this embodiment is configured to vibrate the first vibration parts 51 and 52 in the X-axis direction by piezoelectric driving. In the following, the first vibration part 51 will be described as a representative, and a description of the first vibration part 52 will be omitted. The first vibrating section 51 has a fixed section 518a that is provided inside the first opening 511a and fixed to the substrate 2, and a plurality of connecting sections 518b that are provided inside the first opening 511a and connect the fixed section 518a to the frame section 511. The connecting sections 518b are provided to extend in the Y-axis direction and are spaced apart from each other in the X-axis direction. The vibration means 4 has a pair of piezoelectric elements 45, 46 provided on each of the connecting portions 518b. The piezoelectric elements 45, 46 are provided extending in the Y-axis direction and spaced apart from each other in the X-axis direction.

[0081] The piezoelectric elements 45 and 46 are composed of a pair of electrodes arranged opposite each other in the Z-axis direction and a piezoelectric layer having piezoelectricity interposed between the pair of electrodes. When a voltage is applied between the pair of electrodes, the piezoelectric elements 45 and 46 expand or contract in the Y-axis direction. Therefore, when each piezoelectric element 45 expands and each piezoelectric element 46 contracts, the connecting portions 518b are bent and deformed, and the end connected to the frame portion 511 is displaced toward the ring portion 31, resulting in the inward displacement of the first vibrating portion 51. Conversely, when each piezoelectric element 45 contracts and each piezoelectric element 46 expands, the connecting portions 518b are bent and deformed, and the end connected to the frame portion 511 is displaced toward the opposite side from the ring portion 31, resulting in the outward displacement of the first vibrating portion 51.

[0082] In the vibration means 4 having the above configuration, a voltage is applied to each of the piezoelectric elements 45, 46 so that a state in which each of the piezoelectric elements 45 is expanded while each of the piezoelectric elements 46 is contracted and a state in which each of the piezoelectric elements 45 is contracted while each of the piezoelectric elements 46 is expanded are alternately repeated, thereby vibrating the first vibration parts 51, 52 in the X-axis direction in opposite phases to each other. The fourth embodiment can also achieve the same effects as the first embodiment described above.

[0083] Fifth Embodiment FIG. 11 is a plan view showing a fifth embodiment of the physical quantity sensor of the present invention. The physical quantity sensor of this embodiment will be described focusing on the differences from the above-described embodiment, and a description of the same points will be omitted. The physical quantity sensor 1 of this embodiment is similar to the physical quantity sensor of the first embodiment described above, except for the configuration of the detection means. In Fig. 11, the same components as those of the first embodiment described above are denoted by the same reference numerals. Furthermore, since the configurations of the first vibrating units 51 and 52 are similar to each other, and the configurations of the second vibrating units 53 and 54 are similar to each other, the following description will mainly focus on the first vibrating unit 51 and the second vibrating unit 53, and will omit a description of the first vibrating unit 52 and the second vibrating unit 54.

[0084] The first vibrating part 51 is provided inside the second opening 511b and has a plate-shaped Y-axis direction displacement part 519a that is displaceable in the Y-axis direction relative to the frame part 511, and a plurality of spring parts 519b that connect the Y-axis direction displacement part 519a and the frame part 511. Each spring part 519b is provided to extend in the X-axis direction. Second vibrating portion 53 is provided inside second opening 531b and has plate-shaped X-axis displacement portion 539a that is displaceable in the X-axis direction relative to frame portion 531, and a plurality of spring portions 539b that connect X-axis displacement portion 539a and frame portion 531. Each spring portion 539a is provided extending in the Y-axis direction.

[0085] The detection means 9 has a pair of piezoelectric elements 991, 992 provided on each spring portion 519b of the first vibrating portion 51. The piezoelectric elements 991, 992 extend in the X-axis direction and are spaced apart from each other in the Y-axis direction. The detection means 9 also has a pair of piezoelectric elements 993, 994 provided on each spring portion 539b of the second vibrating portion 53. The piezoelectric elements 993, 994 extend in the Y-axis direction and are spaced apart from each other in the X-axis direction.

[0086] Each of the piezoelectric elements 991, 992, 993, and 994 is composed of a pair of electrodes arranged opposite to each other in the Z-axis direction, and a piezoelectric layer having piezoelectricity interposed between the pair of electrodes. Such piezoelectric elements 991, 992, 993, and 994 have the property of generating electric charge when deformed, and the greater the amount of deformation, the greater the electric charge generated. Therefore, when an angular velocity around the Z axis is applied to the physical quantity sensor 1 and the Y-axis direction displacement portion of the first vibrating portion 51 displaces in the Y-axis direction while bending and deforming the spring portion 519b in the Y-axis direction, the piezoelectric elements 991 and 992 generate a charge of a magnitude corresponding to the amount of deformation of the spring portion 519b, and when the X-axis direction displacement portion of the second vibrating portion 53 displaces in the X-axis direction while bending and deforming the connecting portion 539b in the X-axis direction, the piezoelectric elements 993 and 994 generate a charge of a magnitude corresponding to the amount of deformation of the connecting portion 539b. The detection means 9 detects the magnitude of the electric charges generated from the piezoelectric elements 991, 992, 993, and 994, thereby detecting the angular velocity around the Z axis.

[0087] Sixth Embodiment FIG. 12 is a plan view showing a sixth embodiment of the physical quantity sensor of the present invention. The physical quantity sensor of this embodiment will be described focusing on the differences from the above-described embodiment, and a description of the same points will be omitted. The physical quantity sensor 1 of this embodiment is similar to the physical quantity sensor of the first embodiment described above, except for the configuration of the detection means. In Fig. 12, the same components as those of the first embodiment described above are denoted by the same reference numerals. Furthermore, since the configurations of the first vibrating units 51 and 52 are similar to each other, and the configurations of the second vibrating units 53 and 54 are similar to each other, the following description will mainly focus on the first vibrating unit 51 and the second vibrating unit 53, and will omit a description of the first vibrating unit 52 and the second vibrating unit 54.

[0088] The first vibrating part 51 is provided inside the second opening 511b and has a plate-shaped Y-axis direction displacement part 519a that is displaceable in the Y-axis direction relative to the frame part 511, and a plurality of spring parts 519b that connect the Y-axis direction displacement part 519a and the frame part 511. Each spring part 519b is provided to extend in the X-axis direction. Second vibrating portion 53 is provided inside second opening 531b and has plate-shaped X-axis displacement portion 539a that is displaceable in the X-axis direction relative to frame portion 531, and a plurality of spring portions 539b that connect X-axis displacement portion 539a and frame portion 531. Each spring portion 539a is provided extending in the Y-axis direction.

[0089] The detection means 9 of this embodiment has a piezoresistance element 995 provided on each spring element 519b of the first vibrating element 51, and a piezoresistance element 996 provided on each spring element 539b of the second vibrating element 53. For example, when the vibration system structure 3 is formed using an n-type silicon substrate, the piezoresistance elements 995, 996 can be formed by diffusing impurities such as boron at a high concentration and forming a p-type silicon layer in the diffusion portion.

[0090] The resistance values ​​of the piezoresistance units 995 and 996 change with deformation, and the greater the amount of deformation, the greater the change in resistance value. Therefore, when an angular velocity around the Z axis is applied to the physical quantity sensor 1 and the Y-axis displacement unit of the first vibrating unit 51 displaces in the Y-axis direction while bending and deforming the spring unit 519b in the Y-axis direction, the resistance value of the piezoresistance unit 995 changes to a value corresponding to the amount of deformation of the spring unit 519b, and when the X-axis displacement unit of the second vibrating unit 53 displaces in the X-axis direction while bending and deforming the connecting unit 539b in the X-axis direction, the resistance value of the piezoresistance unit 996 changes to a value corresponding to the amount of deformation of the connecting unit 539b. The detection means 9 detects such a change in the resistance value of the piezoresistance sections 995, 996, thereby detecting the angular velocity around the Z axis.

[0091] Seventh Embodiment Fig. 13 is a plan view showing a seventh embodiment of the physical quantity sensor of the present invention. Note that, for the sake of convenience of explanation, part of the configuration of the physical quantity sensor is not shown in Fig. 13. The physical quantity sensor of this embodiment will be described focusing on the differences from the above-described embodiment, and a description of the same points will be omitted.

[0092] The physical quantity sensor 1 of this embodiment is similar to the physical quantity sensor of the first embodiment described above, except for the configuration of the detection means. In Fig. 13, the same components as those of the first embodiment described above are denoted by the same reference numerals. Furthermore, the configurations of the four vibration units are similar to each other except for the arrangement around the Z axis. Therefore, in the following, the first vibration unit 51 will be described as a representative, and descriptions of the first vibration unit 52 and the second vibration units 53 and 54 will be omitted.

[0093] In first vibrating section 51, Y-axis direction displacement section 516 is provided on the outside of frame section 511 and is connected to frame section 511 by a plurality of spring sections 517. Such Y-axis direction displacement section 516 is composed of plate-shaped base section 516c and a plurality of detection electrodes 516d protruding from base section 516c in the X-axis direction. The displacement transducer 91 of the detection means 9 of this embodiment has a Y-axis direction displacement portion 516 provided on the first vibration portion 51, and a fixed electrode 911 fixed to the substrate 2 via an anchor. A plurality of fixed electrodes 911 are provided corresponding to the detection electrodes 516d of the Y-axis direction displacement portion 516. Each fixed electrode 911 has a pair of electrode pieces 911a, 911b arranged opposite each other with the detection electrode 516d interposed therebetween, and these electrode pieces 911a, 911b are provided extending in the X-axis direction.

[0094] Eighth Embodiment Fig. 14 is a plan view showing an eighth embodiment of the physical quantity sensor of the present invention. Note that, for the sake of convenience of explanation, part of the configuration of the physical quantity sensor is not shown in Fig. 13. The physical quantity sensor of this embodiment will be described focusing on the differences from the above-described embodiment, and a description of the same points will be omitted.

[0095] The physical quantity sensor 1 of this embodiment is similar to the physical quantity sensor of the first embodiment described above, except for the configuration of the detection means. In Fig. 14, the same components as those of the first embodiment described above are denoted by the same reference numerals. Furthermore, the configurations of the four vibration units are similar to each other except for the arrangement around the Z axis. Therefore, the following description will be given of the first vibration unit 51 as a representative, and descriptions of the first vibration unit 52 and the second vibration units 53 and 54 will be omitted.

[0096] In the first vibrating section 51, a Z-axis-about displacement section 516A provided on the outside of the frame section 511 is connected to the frame section 511 by a pair of connecting springs 517A. Each of the pair of connecting springs 517A extends along a radial direction relative to the center O of the ring section 31. The Z-axis-about displacement section 516A has a plate-shaped base section 516Aa and a plurality of fixed electrodes 516Ab protruding from the base section 516Aa in the radial direction relative to the center O of the ring section 31.

[0097] In such first vibrating part 51, when an angular velocity about the Z axis is applied, a Coriolis force in the Y axis direction is generated, causing part 516A displacing about the Z axis to rotate about the Z axis while bending and deforming pair of connecting springs 517A. With such a configuration, the Coriolis force in the Y axis direction can be changed into stress about the Z axis, and therefore the amount of displacement of part 516A displacing about the Z axis can be increased.

[0098] The rotary transducer 91 of the detection means 9 of this embodiment has a Z-axis displacement part 516A provided on the first vibration part 51, and a fixed electrode 911 fixed to the substrate 2 via an anchor. A plurality of fixed electrodes 911 are provided corresponding to the fixed electrodes 516Ab of the Z-axis displacement part 516A. Each fixed electrode 911 has a pair of electrode pieces 911a, 911b arranged opposite each other with the fixed electrode 516Ab interposed therebetween. The vibrator element according to each embodiment as described above can be applied to various electronic devices, and the electronic devices obtained thereby have high reliability.

[0099] Here, an electronic device including a vibrator element of the present invention will be described in detail with reference to FIGS. FIG. 15 is a perspective view showing the configuration of a mobile (or notebook) personal computer to which an electronic device equipped with a physical quantity sensor of the present invention is applied. In this figure, a personal computer 1100 is composed of a main body 1104 equipped with a keyboard 1102 and a display unit 1106 equipped with a display unit 100, and the display unit 1106 is rotatably supported on the main body 1104 via a hinge structure. Such a personal computer 1100 has a built-in physical quantity sensor 1 that functions as angular velocity detection means (gyro sensor).

[0100] FIG. 16 is a perspective view showing the configuration of a mobile phone (including PHS) to which an electronic device equipped with a physical quantity sensor of the present invention is applied. In this figure, a mobile phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206, and a display unit 100 is disposed between the operation buttons 1202 and the earpiece 1204. Such a mobile phone 1200 has a built-in physical quantity sensor 1 that functions as angular velocity detection means (gyro sensor).

[0101] 17 is a perspective view showing the configuration of a digital still camera to which an electronic device equipped with a physical quantity sensor of the present invention is applied. Note that this drawing also shows a simplified illustration of connections to external devices. Here, while a normal camera exposes silver halide photographic film to the light image of the subject, the digital still camera 1300 photoelectrically converts the light image of the subject using an imaging element such as a CCD (Charge Coupled Device) to generate an imaging signal (image signal).

[0102] A display unit is provided on the back of the case (body) 1302 of the digital still camera 1300, and is configured to display an image based on an image signal captured by the CCD. The display unit functions as a finder that displays an image of the subject as an electronic image. Furthermore, on the front side (rear side in the drawing) of the case 1302, a light receiving unit 1304 including an optical lens (image pickup optical system), a CCD, and the like is provided.

[0103] When the photographer checks the subject image displayed on the display unit and presses the shutter button 1306 , the image signal from the CCD at that time is transferred to and stored in the memory 1308 . In addition, in this digital still camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side of the case 1302. As shown in the figure, a television monitor 1430 is connected to the video signal output terminal 1312, and a personal computer 1440 is connected to the data communication input / output terminal 1314, as required. Furthermore, the imaging signal stored in the memory 1308 is configured to be output to the television monitor 1430 or the personal computer 1440 by a predetermined operation. Such a digital still camera 1300 has a built-in physical quantity sensor 1 that functions as angular velocity detection means (gyro sensor).

[0104] In addition to the personal computer (mobile personal computer) of FIG. 15, the mobile phone of FIG. 16, and the digital still camera of FIG. 17, electronic devices equipped with the vibrating element of the present invention can be applied to, for example, inkjet ejection devices (e.g., inkjet printers), laptop personal computers, televisions, video cameras, video tape recorders, car navigation devices, pagers, electronic organizers (including those with communication functions), electronic dictionaries, calculators, electronic game devices, word processors, workstations, videophones, security television monitors, electronic binoculars, POS terminals, medical devices (e.g., electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasonic diagnostic devices, electronic endoscopes), fish finders, various measuring devices, instruments (e.g., instruments for vehicles, aircraft, and ships), flight simulators, etc.

[0105] The physical quantity sensor of the present invention has been described above based on the illustrated embodiment, but the present invention is not limited to this, and the configuration of each part can be replaced with any configuration having a similar function. Furthermore, any other configuration may be added to the present invention. Furthermore, the present invention may be a combination of any two or more configurations (features) of the above-described embodiments. [Explanation of symbols]

[0106] 1. Physical quantity sensor 2. Substrate 3. Vibration system structure 31. Ring portion 4. Vibration means 41. Fixed electrode 411, 412. Electrode piece 42. Fixed electrode 421, 422. Electrode piece 43, 44. Fixed electrode 431, 432. Electrode piece 441, 442. Electrode piece 45, 46. Piezoelectric element 51. First vibrating portion 511. Frame portion 511a. First opening 511b. Second opening 511c. Third opening 512. Z-axis displacement portion 513, 514. Shaft portion 515. Drive electrode 516. Y-axis displacement portion 516A. Displacement portion 516Aa. Base portion 516Ab. Fixed electrode 516a. Frame portion 516b...Detection electrode 516c...Base 516d...Detection electrode 517...Spring part 517A...Pair of connecting springs 518a...Fixed part 518b...Connecting part 519a...Y-axis displacement part 519b...Spring part 52...First vibration part 521...Frame part 522...Z-axis displacement part 523, 524...Axis part 525...Drive electrode 526...Y-axis displacement part 526b...Detection electrode 527...Spring part 53...Second vibration part 531...Frame part 531a...First opening 531b...Second opening 531c...Third opening 532...Z-axis displacement part 533, 534...Axis part 535...Drive electrode 536...X-axis displacement portion 536a...Frame portion 536b...Detection electrode 537...Spring portion 539a...Spring portion 539b...Connecting portion 519a...X-axis displacement portion 519b...Spring portion 54...Second vibration portion 541...Frame portion 542...Z-axis displacement portion 543, 544...Axis portion 545...Drive electrode 546...Detection electrode 546b...Y-axis extension portion 547...Spring portion 61, 62, 63, 64...Inner fixed portion 651, 652, 661, 662, 671, 672, 681, 682...Outer fixed portion 71, 72, 73, 74...Beam 81...First inner spring portion 811, 812...Spring portion 82...First inner spring portion 83...Second inner spring portion 831, 832...Spring portion 84...Second inner spring portion 851, 852, 861, 862, 871, 872, 881, 882...Outer spring portion 9...Detecting means 91...Displacement transducer 911, 912...Fixed electrode 911a, 911b...Electrode piece 92...Displacement transducer921, 922...Fixed electrodes 921a, 921b...Electrode pieces 93...Displacement transducer 931, 932...Fixed electrodes 931a, 931b...Electrode pieces 94...Displacement transducer 941, 942...Fixed electrodes 941a, 941b...Electrode pieces 95...Rotary transducer 951...Fixed electrodes 96...Rotary transducer 961...Fixed electrodes 97...Rotary transducer 971...Fixed electrodes 98...Rotary transducer 981...Fixed electrodes 991, 992...Piezoelectric elements 993, 994...Piezoelectric elements 995, 996...Piezoresistance section 100...Display section 1100...Personal computer 1102...Keyboard 1104...Main body 1106...Display unit 1200...Mobile phone 1202...Operation buttons 1204...Earpiece 1206...Microphone 1300...Digital still camera 1302...Case 1304...Light receiving unit 1306...Shutter button 1308...Memory 1312...Video signal output terminal 1314...Input / output terminal 1430...Television monitor 1440...Personal computer J1, J2...Axis

Claims

1. When the three mutually orthogonal axes are the X-axis, Y-axis, and Z-axis, A substrate; a vibration system structure that is disposed apart from the substrate in a Z-axis direction along the Z-axis and detects angular velocity based on a change in capacitance; a plurality of fixing portions that fix the vibration system structure to the substrate; Including, The vibration system structure is a first vibration unit; a second vibration section disposed apart from the first vibration section in an X-axis direction along the X-axis in a plan view from the Z-axis direction; a connecting portion disposed between the first vibration portion and the second vibration portion in the plan view; a first spring portion connecting the first vibration portion and the connecting portion; a second spring portion connecting the second vibration portion and the connecting portion; a support attached to the substrate; a beam connecting the connecting portion and the support portion; Including, The first vibration unit is a comb-shaped first drive electrode; a first displacement portion that is displaceable in the Z-axis direction; Including, The second vibration unit is a comb-shaped second drive electrode; a second displacement portion that is displaceable in the Z-axis direction; Including, the first drive electrode is disposed between the first displacement portion and the connection portion in the plan view, the second drive electrode is disposed between the second displacement portion and the connection portion in the plan view. A physical quantity sensor characterized by:

2. In claim 1, The physical quantity sensor, wherein the first vibrating portion and the second vibrating portion vibrate in opposite phases to each other.

3. In claim 1 or 2, The vibration system structure is A third vibration unit; a fourth vibration section disposed apart from the third vibration section in the Y-axis direction along the Y-axis in the plan view; a third spring portion connecting the third vibration portion and the connecting portion; a fourth spring portion connecting the fourth vibration portion and the connecting portion; Including, The physical quantity sensor, wherein the connecting portion is disposed between the third vibration portion and the fourth vibration portion in the plan view.

4. In claim 3, The physical quantity sensor, wherein the third vibration section and the fourth vibration section vibrate in opposite phases to each other.

5. In any one of claims 1 to 4, The physical quantity sensor is characterized in that the first drive electrode and the second drive electrode are driven by application of an alternating voltage.

6. In claim 5, A physical quantity sensor characterized in that the frequency of the alternating voltage is approximately equal to the resonance frequency of the vibration system structure.

7. In any one of claims 1 to 6, the first vibration section includes a first transducer that converts a displacement amount of the first displacement section into an electric signal; The physical quantity sensor, wherein the second vibration section includes a second transducer that converts the displacement of the second displacement section into an electrical signal.

8. In claim 1 or 2, The plurality of fixing portions are a first fixing portion that fixes the first vibration portion to the substrate; a second fixing portion that fixes the second vibration portion to the substrate; A physical quantity sensor comprising:

9. In claim 3 or 4, The plurality of fixing portions are a third fixing portion that fixes the third vibration portion to the substrate; a fourth fixing portion that fixes the fourth vibration portion to the substrate; A physical quantity sensor comprising:

10. In any one of claims 1 to 9, The physical quantity sensor is characterized in that the vibration system structure is formed by dry etching a substrate whose main material is silicon.

11. In any one of claims 1 to 10, A physical quantity sensor characterized in that the projected outer shape of the vibration system structure is substantially rectangular.

12. An electronic device comprising the physical quantity sensor according to claim 1 .

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