JP2006208261A - Inertial sensor element - Google Patents

Abstract

A tuning fork-type bending crystal resonator element used as an inertial sensor element has a problem that when it is downsized, the equivalent series resistance R1 is large and the Q value is small, so that high sensitivity cannot be obtained. In addition, even in an element having a structure in which a single through hole is provided in the central portion of the vibration arm portion that has been conventionally performed to solve such a problem, the excitation vibration form of the entire vibration arm for excitation is poor. There is a fear.
In the inertial sensor element, a through-hole having a shape in which an opening major axis is arranged in the length direction of the excitation vibrating arm portion is provided in the excitation vibrating arm portion of the vibrating arm portion. An inertial sensor element formed by arranging a plurality of elements along the length direction.
[Selection] Figure 1

Description

  The present invention relates to an inertial sensor used for attitude control, position detection, camera shake correction, and the like of an aircraft, a ship, an automobile, and the like.

  There are various types of inertial sensors, and there is a vibration type angular velocity sensor that satisfies the requirement of being thin, small and lightweight for incorporation. A conventional vibration type inertial sensor detects a Coriolis force that works with rotation by vibrating a quadrangular prism. As an inertial sensor element used in such a conventional inertial sensor, there is one using an H-type vibration element as shown in FIG. 7 (see Patent Document 1 described later).

  FIG. 7 is a perspective view showing a configuration example of an H-type sensor element 400 as a piezoelectric vibration sensor element used in a conventional inertial sensor. FIG. 8A shows the inertial sensor element 400 shown in FIG. FIG. 8 is a configuration diagram illustrating an electrical connection state of each electrode formed on the vibrating arm portion using a cross-sectional view taken along the virtual cutting line KK ′ illustrated in FIG. It is the block diagram which illustrated the electrical connection state of each electrode of a vibrating arm part using sectional drawing at the time of cut | disconnecting the inertial sensor element 400 of description to the cutting line LL 'described to the same figure. The inertial sensor element 400 shown in FIG. 7 is made of crystal, and is provided with two vibrating arm portions 402 and 403 that are arranged to extend from the base 401 to one side, and to the other side from the base 401. Two vibrating arm portions 404 and 405 are formed. Each vibrating arm is formed in a prismatic shape. Inertial sensor element 400 is fixed (supported) by fixing portion 406.

  The inertial sensor element 400 may be formed from a quartz plate cut and polished at an angle rotated by a predetermined angle (0 to 15 °) with respect to the electrical axis, mechanical axis, and optical axis of the quartz crystal. In the figure, X is an axis rotated by a predetermined angle from the electric axis, Y is an axis rotated by a predetermined angle from the mechanical axis, and Z is an axis rotated by a predetermined angle from the optical axis.

  As shown in FIG. 8A, the vibrating arm portion 402 is formed with a through hole 407, and electrodes 411 and 412 are arranged on the side surface in the longitudinal direction inside the through hole 407. It is arranged so as to have a specific polarity. In addition, electrodes 413 and 414 having the same electrical polarity are disposed on the outer surface of the vibrating arm 402. Here, the electrodes 413 and 414 facing each other with the structure of the electrodes 411 and 412 and the vibrating arm 402 are configured to have different electrical polarities. Similarly, the vibrating arm 403 is provided with a through hole 408, and electrodes 415 and 416 are arranged on the side surface in the longitudinal direction inside the through hole 408, and these electrodes are arranged to have the same electrical polarity. In addition, electrodes 417 and 418 having the same electrical polarity are disposed on the outer surface of the vibrating arm 403. Here, the electrodes 417 and 418 that are opposed to each other with the structure of the electrodes 415 and 416 and the vibrating arm 403 interposed therebetween are configured to have different electrical polarities. The electrodes 411, 412, 417, and 418 are arranged to have the same electrical polarity. Further, the electrodes 413, 414, 415, and 416 are arranged so as to have the same electrical polarity. These electrodes 411, 412, 413, 414, 415, 416, 417, and 418 are arranged as vibrator excitation electrodes and constitute electrode terminals E 41 and E 42.

  As shown in FIG. 8B, the vibrating arm 404 is provided with a through hole 409, and the electrodes 419 and 420 are the same on one of the two side surfaces in the length direction inside the through hole 409. It is provided in the side surface and is configured to have different electrical polarities. On the other side, the electrodes 421 and 422 are configured to have different electrical polarities. The electrodes 419 and 421 are opposed to each other through the space in the through hole and have different electrical polarities, and the electrodes 420 and 422 are also opposed to each other through the space in the through hole so as to have different electrical polarities. It is configured. The electrodes 423, 424, 425, and 426 are configured on the outer surface of the vibrating arm 404 so as to have different electrical polarities from the electrodes in the through holes facing each other across the structure of the vibrating arm 404. .

  Similarly, the vibrating arm portion 405 is provided with a through hole 410, and electrodes 427, 428, 429, and 430 are formed on the side surface in the longitudinal direction inside the through hole, and the vibrating arm portion 405 has an outer surface on the outer surface. Electrodes 431, 432, 433, and 434 are formed, and are configured to have different electrical polarities between electrodes adjacent to each other in the same plane and between electrodes facing each other with the structure of the vibrating arm portion 405 interposed therebetween. Has been. Further, the electrodes 419, 422, 424, 425, 428, 429, 431 and 434 have the same electrical polarity, and the electrodes 420, 421, 423, 426, 427, 430, 432 and 433 have the same electrical polarity. It is configured. These electrodes 419, 420, 421, 422, 423, 424, 425, 426, 427, 428, 429, 430, 431, 432, 433 and 434 are arranged as angular velocity detection electrodes and constitute electrode terminals E43, E44. To do.

  When an AC voltage is applied between the excitation electrode terminals E41 to E42, the electric field Ex41 works alternately in the X-axis direction indicated by the solid and dotted arrows in FIG. 8A, and the vibrating arms 402 and 403 are in the XY plane. Bends and vibrates inside. When the inertial sensor element 400 is excited, if an angular velocity Ω is applied around the Y axis, a Coriolis force corresponding to the angular velocity Ω is generated in a direction perpendicular to the XY plane (Z axis direction). Causes bending vibrations that include directional components. In the vibrating arm portions 404 and 405, an electric field Ex42 indicated by solid and dotted arrows in FIG. 8B is generated. If only the electric charge corresponding to the Z-axis direction generated at the base 401 at this time is dielectrically generated in the electrodes 411, 412, 413, 414, it is possible to detect the magnitude and direction of the angular velocity from the angular velocity detection terminals E 43, E 44. Become.

The following documents are disclosed about the inertial sensor element including the angular velocity sensor element as described above.
JP 2004-301734 A

  In addition, the applicant did not come to discover prior art documents related to the present invention by the time of filing of the present application other than the prior art documents specified by the above prior art document information.

  When the tuning fork type bending crystal resonator element used as the inertial sensor element is reduced in size, there are still problems such as a large equivalent series resistance R1 and a small Q value, which makes it impossible to obtain high sensitivity. For this reason, there has been a demand for an inertial sensor element that is ultra-small, has a small equivalent series resistance R1, a high Q value, and a high angular velocity detection sensitivity. In an element having a conventional structure in which one through hole is provided in the center of the vibrating arm, if one through hole is formed long, a vibration node is created when the exciting vibrating arm is flexibly vibrated. Since the charges cancel each other, a large electrode cannot be provided in the length direction of the excitation vibrating arm, and the excitation vibration form of the entire excitation vibrating arm may be defective.

In order to solve the above-described problem, the inertial sensor element of the present invention includes a base and a plurality of vibrating arms extending in parallel from the base, and the opening arm has a long diameter in the length direction of the vibrating arm. In an inertial sensor element in which a through hole in a form of arranging
Among the vibrating arms, a plurality of through-holes having an opening long diameter in the length direction of the exciting vibrating arm are arrayed and formed along the length direction of the exciting vibrating arm. It is characterized by.

  Further, in the plurality of through holes described above, the long diameter of the opening of the through hole closest to the base in each excitation vibrating arm is longer than the long diameters of the other through holes in the same vibration vibrating arm. Also features.

  Further, the excitation vibrating arm described above is characterized in that, in a plurality of through holes, electrodes of the same electrical polarity are respectively formed on the side surfaces in the longitudinal direction inside the through holes.

  The inertial sensor element of the present invention is an inertial sensor element that vibrates in a flexural vibration mode, and is provided with a plurality of through holes arranged in the longitudinal direction of the vibration arm part for excitation at the center in the width direction of the vibration arm part for excitation. An electrode with the same electrical polarity is arranged on the side surface in the longitudinal direction inside the hole, and an electrode with an electrical polarity different from the electrode on the inner side surface of the through hole is formed on the outer surface of the vibrating arm. R1 is small, the Q value is high, and an even higher angular velocity detection sensitivity can be obtained.

  In addition, each excitation vibrating arm is formed so that the opening long diameter of the through hole closest to the base is longer than the opening long diameter of other through holes in the same excitation vibrating arm. When the arm is bent and vibrated, no vibration node is generated, and the excitation vibration form of the entire vibration arm for excitation is improved. By such an action, the present invention has an effect of providing an inertial sensor element having very excellent inertial sensitivity.

  Embodiments of the present invention will be described below with reference to the drawings. In each figure, a part of the structure is not shown for clarity of explanation. In addition, the dimensions of the structure are also partially exaggerated.

  FIG. 1 is a perspective view showing a configuration example of an H-type inertial sensor element 100 according to an embodiment of the present invention. FIG. 2A shows the inertial sensor element 100 shown in FIG. FIG. 3 is a configuration diagram illustrating an electrical connection state of each electrode formed on the vibrating arm portion using a cross-sectional view taken along the virtual cutting line A-A ′, and (b) is an inertial diagram illustrated in FIG. 1. FIG. 2 is a configuration diagram illustrating an electrical connection state of each electrode of a vibrating arm portion using a cross-sectional view when the sensor element 100 is cut along a cutting line BB ′ illustrated in FIG. 5 is a configuration diagram illustrating an electrical connection state of each electrode of a vibrating arm portion using a cross-sectional view when the inertial sensor element 100 described in FIG. 4 is cut along a cutting line CC ′ illustrated in FIG.

  The inertial sensor element shown in FIG. 1 is made of quartz, and has two vibrating arm portions 102 and 103 that extend from the base 101 to one side and 2 that extend from the base 101 to the other side. The inertial sensor element 100 includes two vibrating arm portions 104 and 105. Each vibrating arm is formed in a prismatic shape. The inertial sensor element 100 is fixed (supported) in a sealed space such as a package on which the inertial sensor element is mounted by a fixing portion 106.

  The inertial sensor element 100 is cut at an angle rotated at a predetermined angle (0 to 15 °) with respect to the electric axis, the mechanical axis, and the optical axis of the crystal body, and then the outer shape is polished and rotated at a predetermined angle from the optical axis. It is formed by cutting out from a quartz plate with a thickness of 0.110 mm whose direction is normal. The X axis of the inertial sensor element 100 in FIG. 1 is an axis rotated by a predetermined angle from the electrical axis, the Y axis is an axis rotated by a predetermined angle from the mechanical axis, and the Z axis is rotated by a predetermined angle from the optical axis. Is the axis. For example, the inertial sensor element 100 is formed to have a thickness of about 0.110 mm, the vibrating arm portions 102 and 103 are formed to have a width of about 0.080 mm and a length of about 1.50 mm, and the vibrating arm portions 104 and 105 have a width of about 0.1 mm. It is formed with a length of about 160 mm and a length of about 1.40 mm. The central axis in the extending direction of the vibrating arm portion 102 and the central axis in the extending direction of the vibrating arm portion 104 coincide, and the central axis in the extending direction of the vibrating arm portion 103 and the central axis of the vibrating arm portion 105 also match. Is formed.

  In FIG. 1, through-holes 107, 108, 109, 110, 111, and 112, in which the long diameters of the hole openings are respectively arranged in the center in the width direction of the vibrating arm portions 102 and 103 from the roots of the vibrating arms in the length direction, At the center in the width direction of the vibrating arm portions 104 and 105, there are provided through holes 113 and 114 in which the long diameter of the hole opening portion is arranged in the length direction from the root of the vibrating arm portion. When forming the outer shape of the sensor element, each through hole is also formed by a method such as wet etching. The through holes 107 and 110 have an opening major axis of about 0.350 mm and a minor axis of about 0.040 mm, and the through holes 108, 109, 111 and 112 have an aperture major axis of about 0.150 mm and a minor axis of about 0.040 mm. Has been.

  2 (a) and 2 (b) show the electrical connection of each electrode formed on the vibrating arm using the cross-sectional view taken along the virtual cutting lines AA 'and BB' shown in FIG. Each of the configuration diagrams illustrating the state is shown. Through holes 107, 108, and 109 are formed in the vibrating arm portion 102. Of the two side surfaces in the length direction inside the through holes 107, 108, and 109, an electrode 115 is provided on one side surface of each through hole, An electrode 116 is formed on the other side surface with the same electrical polarity. Further, electrodes 117 and 118 having the same electrical polarity are disposed on the outer surface of the vibrating arm portion 102, and the structure of the vibrating arm portion 103 is sandwiched between the electrodes 115 or 116 formed in the respective through holes 107, 108 and 109. Are formed in the form of facing each other. Here, the electrodes 117 and 118 facing the electrodes 115 and 116 are configured to have different electrical polarities.

  Similarly, the vibrating arm portion 103 is formed with through holes 110, 111, and 112. Of the two side surfaces in the length direction inside the through holes 110, 111, and 112, an electrode is provided on one side surface of each through hole. 119, and the electrode 120 is formed on the other side surface with the same electrical polarity. Further, electrodes 121 and 122 having the same electrical polarity are sandwiched between the electrodes 119 or 120 formed in the respective through holes 110, 111 and 112 and the structure of the vibrating arm 103 on the outer surface of the vibrating arm 103. Are formed in the form of facing each other. Here, the electrodes 121 and 122 facing the electrode 119 or 120 are formed to have different electrical polarities. The electrodes 115, 116, 121 and 122 are formed to have the same electrical polarity. The electrodes 117, 118, 119 and 120 are formed to have the same electrical polarity. These electrodes 115, 116, 117, 118, 119, 120, 121 and 122 are used as vibrator excitation electrodes, and constitute electrode terminals E11 and E12.

  FIG. 2C is a configuration diagram illustrating the electrical connection state of each electrode formed on the vibrating arm using a cross-sectional view taken along the virtual cutting line CC ′ illustrated in FIG. 1. A through-hole 113 is formed in the vibrating arm 104, and electrodes 123 and 124 are formed on one of the two side surfaces in the length direction inside the through-hole 113 so as to have different electrical polarities. ing. The electrodes 125 and 126 are formed on the other side so as to have different electrical polarities. The electrodes 123 and 125 are opposed to each other through the internal space of the through hole 113 and have different electrical polarities, and the electrodes 124 and 126 are also opposed to each other via the internal space of the through hole 113 and have different electrical polarities. It is formed to become. Of the two outer side surfaces of the vibrating arm portion 104, electrodes 127 and 128 are opposed to the electrodes 123 and 124 formed in the through hole 113 on one side surface with the structure of the vibrating arm portion 104 interposed therebetween, and The electrodes 129 and 130 are formed on the other side so that the electrodes 125 or 126 formed in the through hole 113 have a structure of the vibrating arm 104. The electrodes are opposed to each other and have different electrical polarities between the opposed electrodes.

  Similarly, a through-hole 114 is formed in the vibrating arm 105 so that the electrodes 131 and 132 have different electrical polarities on one of the two side surfaces in the longitudinal direction inside the through-hole 114. Is formed. The electrodes 133 and 134 are formed on the other side so as to have different electrical polarities. The electrodes 131 and 133 are opposed to each other through the inner space of the through hole 114 and have different electrical polarities, and the electrodes 132 and 134 are also opposed to each other via the inner space of the through hole 114 and have different electrical polarities. It is formed to become. Of the two outer side surfaces of the vibrating arm unit 105, electrodes 135 and 136 are opposed to the electrodes 131 and 132 formed in the through hole 114 on one side surface with the structure of the vibrating arm unit 105 interposed therebetween, and The electrodes 137 and 138 are formed on the other side so as to have different electrical polarities between the opposing electrodes, and the structure of the vibrating arm portion 105 is formed with respect to the electrode 133 or 134 formed in the through hole 114. The electrodes are opposed to each other and have different electrical polarities between the opposed electrodes. These electrodes 123, 126, 128, 129, 132, 133, 135, and 138 have the same electrical polarity, and the electrodes 124, 125, 127, 130, 131, 134, 136, and 137 have the same electrical polarity. Is formed. These electrodes 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, and 138 are used as angular velocity detection electrodes, and constitute electrode terminals E13, E14.

  When an AC voltage is applied between the excitation electrode terminals E11 and E12, the electric field Ex11 works alternately in the X-axis direction as shown by the solid and dotted arrows shown in FIGS. The parts 102 and 103 bend and vibrate in the XY plane. In the excitation electrode configuration described above, the electric field Ex11 can be applied in parallel to the electric axis direction in the X-axis direction, and the electric field can be distributed over the entire range of the vibrating arm not only near the root but also in the tip direction. Therefore, an electric field can be applied efficiently. When the inertial sensor element 100 is excited, if an angular velocity Ω is applied around the Y-axis, a Coriolis force corresponding to the angular velocity Ω is generated in a direction perpendicular to the XY plane (Z-axis direction). Causes bending vibrations that include axial components. At this time, an electric field Ex12 represented by a solid line and a dotted line arrow shown in FIG. In this case, the electric field Ex12 in the X-axis direction and the sum thereof become very large, and high angular velocity detection sensitivity can be obtained even when the inertial sensor element is downsized.

  FIG. 3 is a perspective view showing a configuration example of an H-type inertial sensor element 200 according to another embodiment of the present invention. FIG. 4A shows the inertial sensor element 200 shown in FIG. FIG. 4 is a configuration diagram illustrating an electrical connection state of each electrode formed on the vibrating arm portion using a cross-sectional view taken along a virtual cutting line DD ′, and FIG. 3B is an inertial diagram illustrated in FIG. 3. FIG. 6 is a configuration diagram illustrating an electrical connection state of each electrode of a vibrating arm portion using a cross-sectional view when the sensor element 200 is cut along a cutting line EE ′ illustrated in FIG. 5 is a configuration diagram illustrating an electrical connection state of each electrode of the vibrating arm portion using a cross-sectional view when the inertial sensor element 200 described in 1 is cut along a cutting line FF ′ illustrated in FIG. The structure of the inertial sensor element 100 having the shape of the first embodiment shown in FIG. 1 and the structure of the angular velocity detection vibrating arm portion are different.

  As shown in FIG. 3, the inertial sensor element 200 has an integral structure in which the vibrating arm portions 202, 203, 204, and 205 are connected to the base portion 201, and the root of the vibrating arm portion 202 is located at the center in the width direction of the vibrating arm portion 202. Through holes 207, 208 and 209 are formed in the length direction of the vibrating arm portion 202 to have the long diameter of the hole opening. In addition, through holes 210, 211, and 212 are formed at the center in the width direction of the vibrating arm portion 203, with the long diameters of the hole openings extending from the base of the vibrating arm portion 203 in the length direction of the vibrating arm portion 203. In this case, for example, the vibrating arm portions 202 and 203 may be vibrator excitation portions, and the vibrating arm portions 204 and 205 may be angular velocity detection portions. Also in the configuration shown in FIG. 3, as shown in FIG. 1, the necessary electrodes may be formed in each of the vibrator excitation unit and the angular velocity detection unit.

  For example, as shown in FIGS. 4A and 4B, through-holes 207, 208, and 209 are formed in the vibrating arm 202, and two side surfaces in the length direction inside the through-holes 207, 208, and 209 are formed. Of these, an electrode 213 is formed on one side surface of the through hole, and an electrode 214 is formed on the other side surface with the same electrical polarity. Further, electrodes 215 and 216 having the same electrical polarity are sandwiched between the electrodes 213 or 214 formed in the respective through holes 207, 208 and 209 on the outer surface of the vibrating arm 202. Are formed in the form facing each other. Here, the electrodes 213 and 214 and the electrodes 215 and 216 facing the electrodes 213 and 214 are formed to have different electrical polarities. In addition, through holes 210, 211, and 212 are formed in the vibrating arm portion 203. Of the two side surfaces in the length direction inside the through holes 210, 211, and 212, an electrode 220 is provided on one side surface of each through hole. However, the electrode 221 is formed on the other side surface with the same electrical polarity. Further, electrodes 219 and 222 having the same electrical polarity are sandwiched between the electrodes 220 or 221 formed in the respective through holes 210, 211, and 212 on the outer surface of the vibrating arm portion 203. Are formed in the form facing each other. Here, the electrodes 220 and 221 and the electrodes 219 and 222 facing the electrodes 220 and 221 are formed to have different electrical polarities. These electrodes 213, 214, 215, 216, 219, 220, 221 and 222 are used as vibrator excitation electrodes.

  As shown in FIG. 4C, electrodes 223 and 224 are adjacent to one of the two side surfaces of the vibrating arm 204 in the length direction, and electrodes 225 and 226 are adjacent to the other side. The electrodes facing each other across the structure of the matching electrode and the vibrating arm portion 204 are formed to have different electrical polarities. Further, the electrodes 227 and 228 are formed on one side surface of the two side surfaces in the length direction of the vibrating arm portion 205, and the electrodes 229 and 230 are formed on the other side surface. The electrodes facing each other across the body are formed to have different electrical polarities. The electrodes 221, 222, 223, 224, 225, 226, 227, and 228 are angular velocity detection electrodes.

  When an AC voltage is applied to the electrode terminals E21 to E22, the electric field Ex21 works alternately in the X-axis direction indicated by the solid line and the dotted line arrows shown in FIGS. Flexural vibration is performed in the XY plane. At this time, when an angular velocity Ω is applied around the Y axis, Coriolis force corresponding to the angular velocity Ω is generated in a direction perpendicular to the XY plane (Z axis direction), and bending vibration including a Z axis direction component is generated. cause. At this time, an electric field Ex22 represented by the solid and dotted arrows shown in FIG. Also in this case, high angular velocity detection sensitivity can be obtained even when the inertial sensor element is downsized.

  FIG. 5 is a perspective view showing a configuration example of an H-type inertial sensor element 300 according to another embodiment of the present invention. FIG. 6A shows the inertial sensor element 300 shown in FIG. FIG. 6 is a configuration diagram illustrating an electrical connection state of each electrode formed on the vibrating arm portion using a cross-sectional view taken along the virtual cutting line GG ′, and (b) is an inertial diagram illustrated in FIG. 5. It is the block diagram which illustrated the electrical connection state of each electrode of a vibrating arm part using sectional drawing at the time of cut | disconnecting the sensor element 300 by the virtual cutting line HH 'described in the figure, (c) is a figure. 6 is a configuration diagram illustrating an electrical connection state of each electrode of a vibrating arm portion using a cross-sectional view when the inertial sensor element 300 described in FIG. 5 is cut along a virtual cutting line JJ ′ illustrated in FIG. The configuration of the angular velocity detection electrode structure is different from that of the inertial sensor element 100 having the shape of the first embodiment shown in FIG.

  As shown in FIG. 5, the inertial sensor element 300 has an integrated structure in which the vibrating arm portions 302, 303, 304, and 305 are connected to the base portion 301. Through holes 307, 308, and 309 in which the long diameter of the hole opening portion is arranged in the length direction of the vibrating arm portion 302 from the root, in the center in the width direction of the vibrating arm portion 303, the vibrating arm portion 303 extends from the root of the vibrating arm portion 303. Through holes 310, 311, and 312 in which the long diameter of the hole opening is arranged in the length direction of the vibration arm 304, the hole extends from the root of the vibration arm 304 to the length direction of the vibration arm 304 at the center in the width direction of the vibration arm 304. A through-hole 313 having a long diameter of the opening is provided at the center in the width direction of the vibrating arm 305. A through-hole 314 having a long diameter of the hole opening from the base of the vibrating arm 305 to the length of the vibrating arm 305. Are formed respectively. In this case, for example, the vibrating arm portions 302 and 303 are vibrator excitation portions, and the vibrating arm portions 304 and 303 are angular velocity detection portions. Also in the configuration as shown in FIG. 5, as shown in FIG. 1, necessary electrodes are respectively formed on the vibrator excitation unit and the angular velocity detection unit.

  For example, as shown in FIGS. 6A and 6B, the electrode 315 is provided on one side surface and the electrode 316 is provided on the other side surface among the two side surfaces in the longitudinal direction inside each of the through holes 307, 308 and 309. The electrodes 315 and 316 are opposed to the outer surface of the vibrating arm 302 via the structure of the vibrating arm 302, and are electrically different from the electrodes 315 and 316. Polar electrodes 317 and 318 are formed. Each of the through holes 310, 311 and 312 has an electrode 319 formed on one of the two side surfaces in the length direction and an electrode 320 formed on the other side with the same electrical polarity. Electrodes 321 and 322 having different electrical polarities from those of the electrodes 319 and 320 are formed on the outer surface of the portion 303 so as to face the electrode 319 or 320 via the structure of the vibrating arm portion 303. The electrodes 315, 316, 317, 318, 319, 320, 321, 322 are used as vibrator excitation electrodes.

  Further, as shown in FIG. 6C, the electrode 323 is formed on one side surface and the electrode 324 is formed on the other side surface with the same electrical polarity among the two side surfaces inside the through hole 313 of the vibrating arm portion 304. The electrodes 325 and 326 on one side of the two outer sides of the vibrating arm 304, the electrodes 327 and 328 on the other side, the adjacent electrode, the structure of the vibrating arm 304, and the through hole The electrodes facing each other via 313 are formed to have different electrical polarities. The electrode 329 is formed on one side surface of the two side surfaces inside the through-hole 314 of the vibrating arm portion 305, and the electrode 330 is formed on the other side surface with the same electrical polarity. Electrodes 331 and 332 on one side, and electrodes 333 and 334 on the other side, respectively, are adjacent electrodes, and electrodes facing each other through the structure of the vibrating arm 305 and the through hole 314. It is formed so as to have a specific polarity. The electrodes 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, and 334 are angular velocity detection electrodes.

  When an AC voltage is applied to the electrode terminals E31 to E32, the electric field Ex31 works alternately in the X-axis direction indicated by the solid and dotted arrows shown in FIGS. 6A and 6B, and the vibrating arms 302 and 303 Flexural vibration is performed in the XY plane. At this time, if an angular velocity Ω is added around the Y axis, a Coriolis force corresponding to the angular velocity Ω is generated in a direction perpendicular to the XY plane (Z axis direction), causing a bending vibration including a Z axis direction component. . When the electrodes 323, 324, 329, and 330 are analog grounds, an electric field Ex32 represented by solid and dotted arrows shown in FIG. Even in this case, the electric field Ex32 in the X-axis direction and the sum thereof become very large, and high angular velocity detection sensitivity can be obtained even when the inertial sensor element is downsized.

  In each of the above-described embodiments, the number of through holes formed in the vibrating arm portion for excitation is illustrated as three, but the number of through holes formed in the vibrating arm portion for excitation in the present invention is The number is not limited to the number disclosed in the embodiment, and the optimal number is set depending on the length of the vibrating arm portion for excitation and the bending vibration characteristics of the vibrating arm portion for excitation.

FIG. 1 is an external perspective view showing a configuration example of an inertial sensor element according to an embodiment of the present invention. 2A is an electrical diagram of each electrode formed on the vibrating arm using a cross-sectional view when the inertial sensor element shown in FIG. 1 is cut along a virtual cutting line AA ′ shown in FIG. FIG. 2B is a configuration diagram illustrating a connection state, and FIG. 4B is a cross-sectional view when the inertial sensor element illustrated in FIG. 1 is cut along a virtual cutting line BB ′ illustrated in FIG. It is the block diagram which illustrated the electrical connection state of the electrode, (c) is vibration using sectional drawing at the time of cut | disconnecting the inertial sensor element of FIG. 1 with the virtual cutting line CC 'of the figure description. It is the block diagram which illustrated the electrical connection state of each electrode of an arm part. FIG. 3 is an external perspective view showing a configuration example of an inertial sensor element according to another embodiment of the present invention. 4A is an electrical diagram of each electrode formed on the vibrating arm using a cross-sectional view when the inertial sensor element shown in FIG. 3 is cut along a virtual cutting line DD ′ shown in FIG. FIG. 4B is a configuration diagram illustrating a connection state, and FIG. 4B is a cross-sectional view when the inertial sensor element illustrated in FIG. 3 is cut along a cutting line EE ′ illustrated in FIG. FIG. 4C is a configuration diagram illustrating the electrical connection state of FIG. 3C, and FIG. 4C is a vibration arm using a cross-sectional view when the inertial sensor element illustrated in FIG. 3 is cut along a virtual cutting line FF ′ illustrated in FIG. It is the block diagram which illustrated the electrical connection state of each electrode of a part. FIG. 5 is an external perspective view showing a configuration example of an inertial sensor element according to another embodiment of the present invention. 6A is an electrical diagram of each electrode formed on the vibrating arm using a cross-sectional view when the inertial sensor element shown in FIG. 5 is cut along a virtual cutting line GG ′ shown in FIG. FIG. 6B is a configuration diagram illustrating a connection state, and FIG. 5B is a cross-sectional view when the inertial sensor element illustrated in FIG. 5 is cut along a cutting line HH ′ illustrated in FIG. FIG. 6C is a configuration diagram illustrating the electrical connection state of FIG. 5C, and FIG. 5C is a vibration arm using a cross-sectional view when the inertial sensor element illustrated in FIG. 5 is cut along a virtual cutting line JJ ′ illustrated in FIG. It is the block diagram which illustrated the electrical connection state of each electrode of a part. FIG. 7 is an external perspective view showing a configuration example of a conventional inertial sensor element. 8A is an electrical diagram of each electrode formed on the vibrating arm using a cross-sectional view when the inertial sensor element shown in FIG. 7 is cut along a virtual cutting line KK ′ shown in FIG. FIG. 8B is a configuration diagram illustrating a connection state, and FIG. 7B is a cross-sectional view when the inertial sensor element illustrated in FIG. 7 is cut along a cutting line LL ′ illustrated in FIG. It is the block diagram which illustrated the electrical connection state of these.

Explanation of symbols

100, 200, 300 ... inertial sensor elements 101, 201, 301 ... base 102, 103, 104, 105, 202, 203, 204, 205, 302, 303, 304, 305 ... vibrating arm 106, 206, 306 ... fixed Parts 107, 108, 109, 110, 111, 112, 113, 114, 207, 208, 209, 210, 211, 212, 307, 308, 309, 310, 311, 312, 313, 314 ... through holes 115, 116 , 117, 118, 119, 120, 121, 122, 213, 214, 215, 216, 219, 220, 221, 222, 315, 316, 317, 318, 319, 320, 321, 322... 123, 124, 125, 126, 127, 128, 129, 130, 131, 32, 133, 134, 135, 136, 137, 138, 223, 224, 225, 226, 227, 228, 229, 230, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332 333, 334... Angular velocity detection electrode

Claims (3)

In an inertial sensor element comprising a base and a plurality of vibrating arm portions extending in parallel from the base portion, and having a through hole in a form in which an opening major axis is arranged in the length direction of the vibrating arm portion in the vibrating arm portion ,
A plurality of through-holes having an opening major axis in the length direction of the excitation vibration arm portion are provided in the vibration vibration arm portion of the vibration arm portion along the length direction of the excitation vibration arm portion. An inertial sensor element characterized by being arranged and formed individually.   2. The plurality of through holes formed in the excitation vibrating arm portion according to claim 1, wherein each of the excitation vibration arm portions has the same opening major axis that is closest to the base portion. The inertial sensor element according to claim 1, wherein the inertial sensor element is longer than an opening major axis of another through hole in the vibrating arm.   3. A plurality of the through holes in the excitation vibrating arm portion according to claim 1 and 2, wherein electrodes having the same electrical polarity are respectively formed on the side surfaces in the longitudinal direction inside the through holes. The inertial sensor element according to claim 1 and 2.

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