Vibration element, physical quantity sensor, inertial measurement unit, electronic apparatus, and movable body

Abstract

To provide a vibration element that can reduce noise vibration for the outside of the vibration element and a method for manufacturing the same, and to provide a physical quantity sensor, an inertial measurement unit, an electronic apparatus, and a movable body including the vibration element.SOLUTION: A vibration element comprises: a base; vibration arms that extend from the base and have arm parts located closer to the base side and weight parts located closer to a tip than the arm parts; and weight films that are arranged on the weight parts. The weight part has a first principal surface and a second principal surface that are in a front-back relation. The center of gravity of the weight part is at a position closer to the first principal surface side than a center plane in a thickness direction of the arm part. The center of gravity of the weight film is at a position closer to the second principal surface side than the center plane in the thickness direction of the arm part.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a vibration element, a method for manufacturing a vibration element, a physical quantity sensor, an inertial measurement unit, an electronic device, and a moving object. [Background technology]

[0002] Conventionally, vibrating elements used in devices such as quartz crystal resonators and vibrating gyro sensors have been known. Patent Document 1 (Patent Document 1), an example of such a vibrating element, describes a tuning-fork-type quartz crystal vibrating piece. The vibrating arms are provided at their tips with a weight that is thinner than the thickness of the vibrating arms, and a metal film is provided on the weight for adjusting the frequency of the tuning-fork-type quartz crystal vibrating piece. Patent Document 2 (Patent Document 2) also describes a tuning-fork-type piezoelectric vibrating piece. The weight at the tip is provided with a pair of vibrating arms that are bifurcated from the base and extend parallel to the vibrating arms. The weight at the tip, which is wider than the width of the vibrating arms, has a portion thinner than a predetermined thickness. Metal films used for frequency adjustment are provided on both the top and bottom surfaces of the weight. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-311444 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-213262 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the tuning fork-type quartz crystal vibrating pieces described in Patent Documents 1 and 2, the center of gravity of the structure consisting of the weight portion and the metal film is shifted in the thickness direction relative to the central plane of the thickness direction of the arm portion of the vibrating arm. Therefore, when the pair of vibrating arms are vibrated in a direction in which they approach or move away from each other (in-plane direction), the vibrating arms generate vibrations that include a directional component in the thickness direction (out-of-plane direction). As a result, there is a problem in that the vibration component in the thickness direction leaks out of the vibrating element through the base and becomes a source of noise vibration outside the vibrating element.

[0005] An object of the present invention is to provide a vibration element and a manufacturing method thereof that can reduce noise vibrations outside the vibration element, and to provide a physical quantity sensor, an inertial measurement device, an electronic device, and a moving body that include this vibration element. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized as the following application examples or aspects.

[0007] The vibration element of this application example includes a base and a vibrating arm extending from the base and having an arm portion located on the base side and a weight portion located on the tip side of the arm portion; a weight membrane disposed on the weight portion, the weight portion has a first main surface and a second main surface that are opposite surfaces, the center of gravity of the weight portion is located on the first principal surface side of the center plane of the arm portion in the thickness direction, The center of gravity of the weight membrane is located on the second main surface side of the central plane of the arm portion in the thickness direction.

[0008] According to such a vibration element, the center of gravity of the weight is located closer to the first main surface than the central plane of the arm in the thickness direction, while the center of gravity of the weight film is located closer to the second main surface than the central plane of the arm in the thickness direction, so that the center of gravity of the structure consisting of the weight and weight film can be brought closer to the central plane (the center in the thickness direction of the vibrating arm). Therefore, unnecessary vibrations of the vibrating arm (vibrations in the thickness direction) can be reduced, and as a result, noise vibrations outside the vibration element can be reduced.

[0009] In the vibration element of this application example, it is preferable that the weight portion has a first portion and a second portion that is thinner than the first portion, and that the second main surface has a stepped shape due to the first portion and the second portion.

[0010] This allows the center of gravity of the weight portion to be positioned closer to the first main surface than the central plane in the thickness direction of the arm portion with a relatively simple configuration.

[0011] In the vibration element of this application example, it is preferable that the weight portion has a portion between the first portion and the second portion, the thickness of which gradually decreases in plan view from the thickness direction of the weight portion.

[0012] This makes it possible to easily form a continuous weight film spanning the first and second portions, and also reduces the risk of cracks occurring in the weight film due to the step between the first and second portions.

[0013] In the vibration element of this application example, it is preferable that the width of the weight portion is larger than the width of the arm portion in a plan view in the thickness direction. This makes it possible to increase the area of ​​the weight portion on which the weight film can be formed.

[0014] In the vibration element of this application example, it is preferable that the second portions are disposed on both sides of the first portion in the width direction of the vibration arm. This makes it possible to reduce the torsional moment of the vibrating arms.

[0015] In the vibration element of this application example, it is preferable that the second portion be disposed on the opposite side of the first portion from the base portion.

[0016] This allows the area of ​​the second portion to be reduced in plan view, and also has the advantage that the mass balance in the width direction of the weight portion is less likely to be disrupted.

[0017] In the vibration element of this application example, it is preferable that the first portion is provided so as to surround the second portion in a plan view from the thickness direction of the weight portion. This makes it easier to design the second part.

[0018] In the vibration element of this application example, it is preferable that the first main surface is a flat surface. This eliminates the need to process the first main surface side of the mass in order to provide the first and second portions on the mass, and as a result, the manufacturing process of the vibration element can be simplified.

[0019] In the vibration element of this application example, it is preferable that the weight film is disposed on the first portion and the second portion. This allows the mass of the weight film to be increased, and also simplifies the formation of the weight film.

[0020] In the vibration element of this application example, it is preferable that the arm portion has a shape that is plane-symmetrical with respect to a center plane in the thickness direction of the arm portion. This makes it possible to reduce vibration in the thickness direction due to the shape of the vibrating arms.

[0021] In the vibration element of this application example, a first vibrating arm extends from the base and has a first arm portion that is the arm portion and a first weight portion that is the weight portion; a second vibrating arm extending from the base and having a second arm located on the base side and a second weight located on the tip side of the second arm; a first weight film that is the weight film disposed on the first weight portion; a second weight film disposed on the second weight portion, the center of gravity of the second weight portion is located at a position closer to the first principal surface than the center plane of the second arm portion in the thickness direction, The center of gravity of the second weight film is preferably located at a position closer to the second main surface than the center plane in the thickness direction of the second arm portion.

[0022] This reduces unnecessary vibrations (vibrations in the thickness direction) of both the first vibrating arm and the second vibrating arm. Also, since the centers of gravity of the first weight portion and the second weight portion are both located on the first main surface side (the same side as each other), and the centers of gravity of the first weight film and the second weight film are both located on the second main surface side (the same side as each other), these weight portions and weight films can be easily formed.

[0023] The vibration element of this application example includes a driving arm that is driven to vibrate, a detection arm that deforms in response to an inertial force; The base includes a base body and a connecting portion extending from the base body, the driving arm is the vibrating arm and extends from the connecting portion; The detection arm preferably extends from the base body.

[0024] This makes it possible to improve the characteristics of a so-called double T-type vibration element.

[0025] In the vibration element of this application example, a driving arm that extends from the base and is driven to vibrate; a detection arm extending from the base in a direction opposite to the drive arm and deforming in response to an inertial force; The driving arm is preferably the vibrating arm. This makes it possible to improve the characteristics of a so-called H-type vibration element.

[0026] In the vibration element of this application example, it is preferable that the weight film includes a first weight film and a second weight film that is thinner than the first weight film.

[0027] This makes it possible to easily perform fine and rough adjustments when adjusting the resonance frequency of the vibrating arms by removing a part of the weight film with an energy beam such as a laser.

[0028] A method for manufacturing a vibration element according to this application example includes the steps of: forming a base; and a vibration arm extending from the base, having a first main surface and a second main surface that are reversed, and having a center of gravity located closer to the first main surface than a center plane in a thickness direction; forming a weight film on the vibrating arm, the weight film having a center of gravity located on the second main surface side of a central plane in a thickness direction of the vibrating arm; and adjusting the mass of the weight film to adjust the resonance frequency of the vibrating arm.

[0029] This method for manufacturing a vibration element can improve the characteristics of the resulting vibration element. In addition, since it is only necessary to arrange the weight film on one side of the weight portion (specifically, on the second main surface side), the manufacturing process of the vibration element is simplified, and it is also possible to reduce splashes (dross) that occur when adjusting the resonance frequency of the vibrating arm by removing part of the weight film with an energy beam such as a laser.

[0030] The physical quantity sensor of this application example includes the vibration element of this application example, and a package that houses the vibration element.

[0031] According to such a physical quantity sensor, the excellent characteristics of the vibration element can be utilized to improve the sensor characteristics (for example, detection accuracy) of the physical quantity sensor.

[0032] The inertial measurement unit of this application example includes the physical quantity sensor of this application example, and a circuit electrically connected to the physical quantity sensor.

[0033] According to such an inertial measurement unit, the excellent sensor characteristics of the physical quantity sensor can be utilized to improve the characteristics (for example, measurement accuracy) of the inertial measurement unit.

[0034] The electronic device of this application example is characterized by including the vibration element of this application example. According to such an electronic device, the excellent characteristics of the vibration element can be utilized to improve the characteristics (for example, reliability) of the electronic device.

[0035] The moving body of this application example is characterized by including the vibration element of this application example. According to such a moving body, the excellent characteristics of the vibration element can be utilized to improve the characteristics (for example, reliability) of the moving body. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a plan view showing a vibration element according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] 3 is an enlarged plan view showing a weight portion and a weight film of a vibrating arm (driving arm) of the vibration element. FIG. [Figure 4] 4 is a cross-sectional view taken along line BB in FIG. 3. [Figure 5] 4 is a cross-sectional view taken along line CC in FIG. 3. [Figure 6] 10 is a flowchart illustrating an example of a method for manufacturing a vibration element. [Figure 7] 10A and 10B are cross-sectional views showing a step of preparing a substrate in a vibrator element forming step. [Figure 8] 10A and 10B are cross-sectional views showing a step of forming a corrosion-resistant film and a resist film in a vibrating reed forming step. [Figure 9] 10A to 10C are cross-sectional views showing a step of forming the outer shape of the vibrating reed in the vibrating reed forming step. [Figure 10] 10A and 10B are cross-sectional views showing a step of removing a part of the corrosion-resistant film in the vibrating piece forming step. [Figure 11] 10A and 10B are cross-sectional views showing a step of forming a groove in a vibrating element forming step. [Figure 12] 10A and 10B are cross-sectional views showing a step of removing a corrosion-resistant film and a resist film in a vibrator element forming step. [Figure 13]10A to 10C are cross-sectional views showing an electrode forming step. [Figure 14] 10A to 10C are cross-sectional views showing a step of forming an iron film. [Figure 15] FIG. 10 is a cross-sectional view showing a frequency adjusting step. [Figure 16] 10 is an enlarged plan view showing a weight portion and a weight film of a vibrating arm (driving arm) of a vibration element according to a second embodiment of the present invention. FIG. [Figure 17] 17 is a cross-sectional view taken along line CC in FIG. 16. [Figure 18] 10 is an enlarged plan view showing a weight portion and a weight film of a vibrating arm (driving arm) of a vibration element according to a third embodiment of the present invention. FIG. [Figure 19] 10 is an enlarged plan view showing a weight portion and a weight film of a vibrating arm (driving arm) of a vibration element according to a fourth embodiment of the present invention. FIG. [Figure 20] 19 along the line BB. [Figure 21] FIG. 10 is a plan view showing a vibration element according to a fifth embodiment of the present invention. [Figure 22] FIG. 10 is a plan view showing a vibration element according to a sixth embodiment of the present invention. [Figure 23] FIG. 1 is a cross-sectional view showing a physical quantity sensor according to an embodiment of the present invention. [Figure 24] 1 is an exploded perspective view showing an embodiment of an inertial measurement unit of the present invention; [Figure 25] FIG. 25 is a perspective view of a substrate provided in the inertial measurement unit shown in FIG. 24. [Figure 26] 1 is a perspective view showing an embodiment of an electronic device of the present invention (a mobile (or notebook) personal computer). [Figure 27] 1 is a plan view showing an embodiment (mobile phone) of an electronic device of the present invention. [Figure 28] 1 is a perspective view showing an embodiment (digital still camera) of an electronic device of the present invention. [Figure 29] 1 is a perspective view showing an embodiment (automobile) of a moving body of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] DETAILED DESCRIPTION OF THE INVENTION A vibration element, a vibration element manufacturing method, a physical quantity sensor, an inertial measurement device, an electronic device, and a moving object according to the present invention will be described in detail below based on embodiments shown in the accompanying drawings.

[0038] 1. Vibration element and manufacturing method thereof First Embodiment First, the vibration element and the manufacturing method thereof will be described.

[0039] (vibration element) FIG. 1 is a plan view showing a vibration element according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. FIG. 3 is an enlarged plan view showing the weight portion and weight film of the vibration arm (driving arm) of the vibration element. FIG. 4 is a cross-sectional view taken along line BB in FIG. 3. FIG. 5 is a cross-sectional view taken along line CC in FIG. 3. In each drawing, the dimensions of each part are exaggerated as necessary, and the dimensional ratios between each part do not necessarily coincide with the actual dimensional ratios. The position, direction, size, etc. of each part described below include the range of manufacturing errors (for example, a difference within ±1%) and are not limited to the position, direction, size, etc. described in this specification as long as the required functions of each part can be realized.

[0040] For ease of explanation, the following description will use the x-axis, y-axis, and z-axis, which are three mutually perpendicular axes. Hereinafter, the direction parallel to the x-axis will be referred to as the "x-axis direction," the direction parallel to the y-axis as the "y-axis direction," and the direction parallel to the z-axis as the "z-axis direction." In the drawings, the tip end of the arrows representing the x-axis, y-axis, and z-axis will be designated as "+" and the base end as "-." The +z-axis side will also be referred to as "top," the -z-axis side as "bottom," the +x-axis side as "right," and the -x-axis side as "left." The view from the z-axis direction will also be referred to as a "planar view." For ease of explanation, the electrode film 4, which will be described later, is omitted from FIG. 1 .

[0041] The vibration element 1 shown in Fig. 1 is a sensor element that detects angular velocity around the z-axis. The vibration element 1 has a vibration element 2 (see Fig. 1), an electrode film 4 (see Fig. 2) disposed on the vibration element 2, and a weight film 3 (see Fig. 1) disposed on the electrode film 4.

[0042] 1, the vibrating element 2 has a so-called double T-type structure. Specifically, the vibrating element 2 has a base 21, a pair of detection arms 22 and 23 (first and second detection arms) extending from the base 21, a pair of drive arms 24 and 25 (first drive arms), and a pair of drive arms 26 and 27 (second drive arms).

[0043] Here, the base 21 has a base main body 211 supported by a package 11 (see FIG. 22 ), which will be described later, a connecting arm 212 extending from the base main body 211 along the +x-axis direction, and a connecting arm 213 extending from the base main body 211 along the −x-axis direction opposite to the extension direction of the connecting arm 212. The detection arm 22 (first detection arm) extends from the base main body 211 along the +y-axis direction that intersects with the extension direction of the connecting arms 212 and 213, while the detection arm 23 (second detection arm) extends from the base main body 211 along the −y-axis direction opposite to the extension direction of the detection arm 22. The drive arm 24 (first drive arm) extends from the tip region of the connecting arm 212 along the +y-axis direction, whereas the drive arm 25 (first drive arm) extends from the tip region of the connecting arm 212 along the -y-axis direction, which is the opposite direction to the extension direction of the drive arm 24. Similarly, the drive arm 26 (second drive arm) extends from the tip region of the connecting arm 213 along the +y-axis direction, whereas the drive arm 27 extends from the tip region of the connecting arm 213 along the -y-axis direction, which is the opposite direction to the extension direction of the drive arm 26.

[0044] Detection arm 22 has arm portion 221 (detection arm portion) extending from base body 211, weight portion 222 (detection weight portion) provided on the tip side of arm portion 221 and wider than arm portion 221, and grooves 223 provided on each of the upper and lower surfaces of arm portion 221. Similarly, detection arm 23 has arm portion 231 (detection arm portion), weight portion 232 (detection weight portion), and a pair of grooves 233. Drive arm 24 has arm portion 241 (drive arm portion) extending from connecting arm 212, weight portion 242 (drive weight portion) provided on the tip side of arm portion 241 and wider than arm portion 241, and a pair of grooves 243 provided on the upper and lower surfaces of arm portion 241. Similarly, drive arm 25 has arm 251 (drive arm), weight 252 (drive weight), and a pair of grooves 253. Drive arm 26 has arm 261 (drive arm) extending from connecting arm 213, weight 262 (drive weight) provided on the tip side of arm 261 and wider than arm 261, and a pair of grooves 263 provided on the upper and lower surfaces of arm 261. Similarly, the drive arm 27 has an arm portion 271 (drive arm portion), a weight portion 272 (drive weight portion), and a pair of grooves 273.

[0045] At least one of the upper and lower pairs of grooves 223, 233, 243, 253, 263, and 273 may be omitted. Furthermore, the upper and lower pairs of grooves 223, 233, 243, 253, 263, and 273 may be connected to each other. That is, through holes opening to the upper and lower surfaces may be provided in arm portions 221, 231, 241, 251, 261, and 271. Furthermore, the width of weight portions 222, 232, 242, 252, 262, and 272 may be equal to or smaller than the width of arm portions 221, 231, 241, 251, 261, and 271.

[0046] Here, arm 221 is a portion that bends (deforms) when detection arm 22 vibrates (during detection vibration), and is a portion that detects electric charges generated in association with the detection vibration of detection arm 22 (a portion where detection signal electrode 43 and detection ground electrode 44, which will be described later, are provided). Similarly, arm 231 is a portion that bends (deforms) when detection arm 23 vibrates (during detection vibration), and is a portion that detects electric charges generated in association with the detection vibration of detection arm 23 (a portion where detection signal electrode 43 and detection ground electrode 44, which will be described later, are provided). Furthermore, arm 241 is a portion that bends (deforms) when drive arm 24 vibrates (during drive vibration), and is a portion to which an electric field for driving drive arm 24 is applied (a portion where drive signal electrode 41 and drive ground electrode 42, which will be described later, are provided). Similarly, arm portions 251, 261, and 271 are portions that bend (deform) when drive arms 25, 26, and 27 vibrate (during drive vibration), and are portions to which an electric field is applied for driving drive arms 25, 26, and 27 (portions where drive signal electrode 41 and drive ground electrode 42, described later, are provided). Furthermore, weight portion 222 is a portion closer to the tip than arm portion 221. Similarly, weight portions 232, 242, 252, 262, and 272 are portions closer to the tip than arms 231, 241, 251, 261, and 271, respectively.

[0047] As shown in FIG. 3, weight 242 has a first portion 242a on an extension of arm 241 and a pair of second portions 242b and 242c on both sides of first portion 242a in the width direction. As shown in FIG. 4, thickness t2 of each of second portions 242b and 242c is thinner than thickness t1 of first portion 242a. While first main surface 2a is flat, second main surface 2b has steps 244 and 245 formed between first portion 242a and second portions 242b and 242c. These steps 244 and 245 include inclined surfaces, and weight 242 gradually becomes thicker from the second portions 242b and 242c toward first portion 242a. Such second portions 242b and 242c can be formed by etching (anisotropic etching) the second main surface 2b of the weight portion 242, as will be described later.

[0048] 4, the center of gravity G1 of such weight portion 242 is located on the first main surface 2a side of the first main surface 2a (lower surface) and the second main surface 2b (upper surface) which are opposite sides of weight portion 242 with respect to the center C in the thickness direction of drive arm 24. That is, the centers of gravity G1 of weight portions 242, 252, 262, 272 are located on the first main surface 2a side of the center plane CP of arm portions 241, 251, 261, 271 in the thickness direction, while the centers of gravity G2 of weight membranes 33, 34, 35, 36 are located on the second main surface 2b side of the center plane CP of arm portions 241, 251, 261, 271 in the thickness direction. By shifting the center of gravity G1 in the thickness direction from the center C in this way, it is possible to achieve balance with the weight film 33, which has a center of gravity G2 located on the opposite side from the center of gravity G1 of the weight 242, as will be described later. Similar to this weight 242, the centers of gravity G1 of the weights 252, 262, and 272 are located on the first main surface 2a side of the first main surface 2a (lower surface) and the second main surface 2b (upper surface) that are opposite sides of the weights 252, 262, and 272, with respect to the center C in the thickness direction of the drive arms 25, 26, and 27. The centers of gravity of the weights 222 and 232 may also be located on the first main surface side of the first main surface (lower surface) and the second main surface (upper surface) that are opposite sides of the weights 222 and 232, with respect to the center in the thickness direction of the detection arms 22 and 23.

[0049] Here, the "central plane CP in the thickness direction of arm portion 241" refers to a plane perpendicular to the thickness direction (z-axis direction) of arm portion 241, where the distance between the outermost point in the thickness direction on first principal surface 2a side of arm portion 241 and the outermost point in the thickness direction on second principal surface 2b side is equal. The central planes in the thickness direction of arm portions 251, 261, and 271 are also defined in the same manner as central plane CP in the thickness direction of arm portion 241. The "weight film 33" refers to a laminate (on drive arm 24) that has a larger mass per unit area than the electrode film 4 (drive signal electrode 41 and drive ground electrode 42) of arm portion 241. The weight films 34, 35, and 36 are also defined in the same manner as weight film 33.

[0050] Furthermore, the depth d1 of the steps 244, 245 of the second main surface 2b described above, i.e., the difference between the thickness t1 of the first portion 242a and the thickness t2 of the second portions 242b, 242c, is not particularly limited, but is preferably equal to the depth d2 of the groove 243 described above (see FIG. 5). This allows the steps 244, 245 to be formed together with the groove 243 by etching. The depth d1 of the steps is preferably 0.1 to 0.5 times, and more preferably 0.15 to 0.4 times, the thickness t1 of the weight portion 242.

[0051] Furthermore, the widths Wb and Wc of the second portions 242b and 242c may be equal to or different from each other, but it is preferable that the width Wc of the second portion 242c be greater than the width Wb of the second portion 242b. When the vibrating element 2 is formed by anisotropic etching of a Z-cut quartz crystal plate, the average thickness of the second portion 242c becomes thicker than the average thickness of the second portion 242b due to the anisotropy. Therefore, by making the width Wc of the second portion 242c greater than the width Wb of the second portion 242b, the mass of the second portion 242b can be made equal to the mass of the second portion 242c.

[0052] The specific widths Wb and Wc of second portions 242b and 242c are determined depending on the thickness and area of ​​weight film 33, which will be described later, and are not particularly limited, but are approximately 0.3 to 0.8 times the width Wa of first portion 242a. The areas of second portions 242b and 242c in a plan view are not particularly limited, but are, for example, approximately 0.1 to 2 times the area of ​​first portion 242a in a plan view.

[0053] The vibrating element 2 is made of a Z-cut quartz crystal plate. By making the vibrating element 2 out of quartz crystal (Z-cut quartz crystal plate), the vibration characteristics (particularly frequency-temperature characteristics) of the vibrating element 2 can be improved. Furthermore, the vibrating element 2 can be formed with high dimensional accuracy by etching. Quartz crystal belongs to the trigonal crystal system and has X-axis, Y-axis, and Z-axis, which are perpendicular to each other as crystal axes. The X-axis, Y-axis, and Z-axis are called the electrical axis, mechanical axis, and optical axis, respectively. A Z-cut quartz crystal plate is a plate-shaped quartz crystal substrate that extends in the XY plane defined by the Y-axis (mechanical axis) and X-axis (electrical axis) and has a thickness in the Z-axis (optical axis) direction. Here, the X-axis of the quartz crystal that makes up the vibrating element 2 is parallel to the x-axis, the Y-axis is parallel to the y-axis, and the Z-axis is parallel to the z-axis.

[0054] The vibrating element 2 may be made of a piezoelectric material other than quartz. Examples of piezoelectric materials other than quartz include lithium tantalate, lithium niobate, lithium borate, and barium titanate. Depending on the configuration of the vibrating element 2, the vibrating element 2 may be made of a quartz crystal plate with a cut angle other than a Z-cut. The vibrating element 2 may be made of a material other than a piezoelectric material (a material that does not have piezoelectricity), such as silicon. In this case, a piezoelectric element (an element having a piezoelectric film made of PZT or the like sandwiched between a pair of electrodes) may be disposed on each of the detection arms 22 and 23 and the drive arms 24, 25, 26, and 27.

[0055] An electrode film 4 is provided on the surface of the vibrating element 2 configured in this manner. As shown in Fig. 2, this electrode film 4 has a drive signal electrode 41, a drive ground electrode 42, a detection signal electrode 43, a detection ground electrode 44, and a plurality of terminals (not shown) electrically connected to these electrodes.

[0056] The drive signal electrodes 41 are electrodes for exciting drive vibrations in the drive arms 24, 25, 26, and 27. As shown in Fig. 2, the drive signal electrodes 41 are provided on the top and bottom surfaces of the arm portion 241 of the drive arm 24 and on both side surfaces of the arm portion 261 of the drive arm 26. Similarly, although not shown, the drive signal electrodes 41 are provided on the top and bottom surfaces of the arm portion 251 of the drive arm 25 and on both side surfaces of the arm portion 271 of the drive arm 27.

[0057] On the other hand, the drive ground electrode 42 has a reference potential (for example, ground potential) with respect to the drive signal electrode 41. As shown in Fig. 2, the drive ground electrodes 42 are provided on both side surfaces of the arm portion 241 of the drive arm 24 and on the top and bottom surfaces of the arm portion 261 of the drive arm 26. Similarly, although not shown, drive ground electrodes 42 are provided on both side surfaces of the arm portion 251 of the drive arm 25 and on the top and bottom surfaces of the arm portion 271 of the drive arm 27.

[0058] The detection signal electrodes 43 are electrodes for detecting charges generated by detection vibrations when the detection vibrations are excited in the detection arm 22. As shown in FIG. 2 , the detection signal electrodes 43 are provided on the upper and lower surfaces of the arm portion 221 of the detection arm 22.

[0059] On the other hand, the detection ground electrode 44 has a reference potential (for example, ground potential) with respect to the detection signal electrode 43. As shown in Fig. 2, the detection ground electrode 44 is provided on both side surfaces of the arm portion 221 of the detection arm 22. Similarly, although not shown, the detection ground electrode 44 is provided on the top and bottom surfaces of the arm portion 231 of the detection arm 23.

[0060] Although not shown, detection signal electrodes for detecting charges generated by detection vibration when detection vibration of detection arm 23 is excited are provided on the upper and lower surfaces of arm portion 231 of detection arm 23. Similarly, detection ground electrodes of detection arm 23 have a reference potential (e.g., ground potential) with respect to the detection signal electrode of detection arm 23, and are provided on both sides of arm portion 231 of detection arm 23. Vibration may be detected by a differential signal between detection signal electrode 43 of detection arm 22 and the detection signal electrode of detection arm 23.

[0061] The constituent materials of the electrode film 4 are not particularly limited, and examples thereof include metal materials such as gold (Au), gold alloys, platinum (Pt), aluminum (Al), aluminum alloys, silver (Ag), silver alloys, chromium (Cr), chromium alloys, copper (Cu), molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt (Co), zinc (Zn), and zirconium (Zr), as well as transparent electrode materials such as ITO and ZnO. Among these, it is preferable to use a metal containing gold as the main component (gold, gold alloy) or platinum. Note that a layer of Ti, Cr, or the like may be provided between the electrode film 4 and the vibrating bar 2 as a base layer that functions to prevent the electrode film 4 from peeling off from the vibrating bar 2.

[0062] Such an electrode film 4 has portions that are disposed on the weight portions 222, 232, 242, 252, 262, and 272 of the above-described vibrating element 2. The weight film 3 is disposed on the weight portions 222, 232, 242, 252, 262, and 272 via these portions. Note that the electrode film 4 does not necessarily have to be disposed directly below the weight film 3.

[0063] 1 , weight film 3 includes weight film 31 arranged on weight portion 222, weight film 32 arranged on weight portion 232, weight film 33 arranged on weight portion 242, weight film 34 arranged on weight portion 252, weight film 35 arranged on weight portion 262, and weight film 36 arranged on weight portion 272. Weight films 31 and 32 are films that can be used to adjust the resonance frequency of detection arms 22 and 23 by being appropriately removed with an energy beam such as a laser. Weight films 33, 34, 35, and 36 are films that can be used to adjust the resonance frequency of drive arms 24, 25, 26, and 27 by being appropriately removed with an energy beam such as a laser.

[0064] Of the first main surface 2a (lower surface) and the second main surface 2b (upper surface) which are opposite sides of the weight portion 242, the weight film 33 is arranged on the second main surface 2b, but not on the first main surface 2a. Furthermore, weight membrane 33 is not arranged on the side surfaces (left and right side surfaces and tip surface) of weight portion 242 either. In this embodiment, weight film 33 is provided over the entire area in the width direction (x-axis direction) of weight section 242, excluding a portion on the base end side of weight section 242. Therefore, weight film 33 is disposed across first portion 242a and second portions 242b and 242c of weight section 242.

[0065] 4, the center of gravity G2 of weight membrane 33 is located on the second main surface 2b side of the first main surface 2a (lower surface) and the second main surface 2b (upper surface) that are opposite sides of weight section 242, relative to the center C in the thickness direction of drive arm 24. By shifting the center of gravity G2 in the thickness direction from center C in this way, it is possible to achieve balance with weight section 242, which has a center of gravity G1 that is located on the opposite side of center of gravity G2 of weight membrane 33, as described above. Similar to weight membrane 33, weight membranes 34, 35, and 36 are located on the second main surface 2b side of the first main surface 2a (lower surface) and the second main surface 2b (upper surface) that are opposite sides of weight sections 252, 262, and 272, relative to the center C in the thickness direction of drive arms 25, 26, and 27, respectively. Furthermore, weight films 31 and 32 are located on the second principal surface side of first principal surface (lower surface) and second principal surface (upper surface) of weight portions 222 and 232, respectively, relative to the center in the thickness direction of detection arms 22 and .

[0066] The positions, sizes, and ranges of weight films 31-36 are not limited to those shown in the drawings. For example, weight film 3 may be disposed on first main surface 2a and the side surfaces of weight sections 222, 232, 242, 252, 262, and 272. In this case, the thicknesses and locations of weight films 33, 34, 35, and 36, excluding weight films 31 and 32, may be adjusted so that their centers of gravity G2 are located on the second main surface 2b side. Weight film 3 may also be provided over the entire length (y-axis) of weight sections 222, 232, 242, 252, 262, and 272.

[0067] The material for forming the weight film 3 is not particularly limited, and may be, for example, a metal, an inorganic compound, or a resin. However, it is preferable to use a metal or an inorganic compound. A metal or an inorganic compound can be easily and precisely formed into a film by a vapor deposition method. Furthermore, weight films 31 to 36 made of a metal or an inorganic compound can be removed efficiently and precisely by irradiating them with an energy beam. For these reasons, forming the weight film 3 by forming a film of a metal or an inorganic compound makes the frequency adjustment, which will be described later, more efficient and precise.

[0068] Examples of such metals include nickel (Ni), gold (Au), gold alloys, platinum (Pt), aluminum (Al), aluminum alloys, silver (Ag), silver alloys, chromium (Cr), chromium alloys, copper (Cu), molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt (Co), zinc (Zn), and zirconium (Zr). These metals can be used alone or in combination. Among these, Al, Cr, Fe, Ni, Cu, Ag, Au, Pt, or alloys containing at least one of these metals are preferred, since the weight film 3 can be formed using the same equipment as the electrode film 4. More specifically, the weight film 3 preferably has a structure in which an upper layer made of Au (gold) is laminated on a base layer made of Cr (chromium). This provides excellent adhesion to the vibrating element 2 or electrode film 4 formed using quartz crystal, and allows for highly accurate and efficient adjustment of the resonant frequency.

[0069] Examples of such inorganic compounds include oxide ceramics such as alumina (aluminum oxide), silica (silicon oxide), titania (titanium oxide), zirconia, yttria, and calcium phosphate; nitride ceramics such as silicon nitride, aluminum nitride, titanium nitride, and boron nitride; carbide ceramics such as graphite and tungsten carbide; and ferroelectric materials such as barium titanate, strontium titanate, PZT, PLZT, and PLLZT. Among these, silicon oxide (SiO2), titanium oxide (TiO2), and oxide ceramics are particularly preferred. It is preferable to use an insulating material such as aluminum oxide (Al2O3).

[0070] The thickness (average thickness) of the weight film 3 is not particularly limited, but is, for example, about 10 nm or more and 10,000 nm or less.

[0071] The vibration element 1 configured as described above detects angular velocity ω about the z-axis as follows. First, by applying a voltage (drive signal) between the drive signal electrode 41 and the drive ground electrode 42, the drive arms 24 and 26 are caused to undergo bending vibration (drive vibration) in the direction indicated by arrow a in FIG. 1 so as to repeatedly approach and move away from each other, and the drive arms 25 and 27 are caused to undergo bending vibration (drive vibration) so as to repeatedly approach and move away from each other in the same direction as the bending vibration. At this time, if no angular velocity is applied to the vibration element 1, the drive arms 24 and 25 and the drive arms 26 and 27 vibrate symmetrically with respect to the yz plane passing through the center point (center of gravity G), and therefore the base body 211, the connecting arms 212 and 213, and the detection arms 22 and 23 hardly vibrate. Furthermore, as mentioned above, since the center of gravity G1 of the weight portions 242, 252, 262, and 272 and the center of gravity G2 of the weight membranes 33, 34, 35, and 36 are located on opposite sides of the centers C of the drive arms 24, 25, 26, and 27, vibration of the drive arms 24, 25, 26, and 27 in the out-of-plane direction can be reduced.

[0072] When an angular velocity ω about a normal line passing through the center of gravity G (i.e., about the z-axis) is applied to the vibration element 1 while the drive arms 24-27 are driven to vibrate in this manner (drive mode), a Coriolis force acts on each of the drive arms 24-27. This causes the connecting arms 212 and 213 to flexurally vibrate in the direction indicated by arrow b in FIG. 1. Accordingly, flexural vibration (detection vibration) is excited in the detection arms 22 and 23 in the direction indicated by arrow c in FIG. 1, so as to cancel out this flexural vibration. Such detection vibration (detection mode) of the detection arms 22 and 23 then generates an electric charge between the detection signal electrode 43 and the detection ground electrode 44. The angular velocity ω applied to the vibration element 1 can be calculated based on this electric charge.

[0073] As described above, the vibration element 1 includes the base 21, the drive arms 24, 25, 26, 27 that extend from the base 21 and are vibrating arms having the arm portions 241, 251, 261, 271 located on the base 21 side and the weight portions 242, 252, 262, 272 located on the tip side of the arm portions 241, 251, 261, 271, and the weight films 33, 34, 35, 36 that are arranged on the weight portions 242, 252, 262, 272. Here, the weight portions 242, 252, 262, 272 have the first main surface 2a and the second main surface 2b that are opposite each other. The center of gravity G1 of weights 242, 252, 262, and 272 is located closer to the first main surface 2a than the central plane CP in the thickness direction of arm portions 241, 251, 261, and 271 (a plane that passes through the center C in the thickness direction of drive arms 24, 25, 26, and 27 and is perpendicular to the z-axis). In contrast, the center of gravity G2 of weight membranes 33, 34, 35, and 36 is located closer to the second main surface 2b than the central plane CP in the thickness direction of arm portions 241, 251, 261, and 271.

[0074] According to such vibration element 1, the centers of gravity G1 of weights 242, 252, 262, and 272 are located closer to first main surface 2a than central plane CP of arm portions 241, 251, 261, and 271 in the thickness direction, whereas the centers of gravity G2 of weight films 33, 34, 35, and 36 are located closer to second main surface 2b than central plane CP of arm portions 241, 251, 261, and 271 in the thickness direction. This allows the center of gravity of the entire structure made up of weights 242, 252, 262, and 272 and weight films 33, 34, 35, and 36 to be closer to central plane CP (centers C of drive arms 24, 25, 26, and 27). This reduces unnecessary vibrations (vibrations in the thickness direction) of drive arms 24, 25, 26, and 27, and as a result, reduces noise vibrations external to vibration element 1. Furthermore, as will be described later, the manufacturing method requires that the weight films 33, 34, 35, and 36 are arranged on only one side of the weight portions 242, 252, 262, and 272 (specifically, on the second main surface 2b side), which simplifies the manufacturing process of the vibration element 1 and also reduces the amount of dross that is generated when adjusting the resonant frequency of the vibrating arm by removing portions of the weight films 33, 34, 35, and 36 with an energy beam such as a laser.

[0075] Furthermore, since the centers of gravity G1 of the weights 242, 252, 262, and 272 are all located on the first main surface 2a side (the same side as each other), and the centers of gravity G2 of the weight films 33, 34, 35, and 36 are all located on the second main surface side (the same side as each other), these weights 242, 252, 262, and 272 and weight films 33, 34, 35, and 36 can be easily formed. One of the drive arms 24, 25, 26, and 27 corresponds to a "first vibrating arm," and the other corresponds to a "second vibrating arm." The first vibrating arm has one of the arms 241, 251, 261, and 271 as a first arm, and has a weight of the weights 242, 252, 262, and 272 connected to the first arm as a first weight. The second vibrating arm has, as a second arm, a weight portion different from the first weight portion among arms 241, 251, 261, and 271, and has, as a second weight portion, a weight portion connected to the second arm among weight portions 242, 252, 262, and 272. Furthermore, any one of weight films 33, 34, 35, and 36 is arranged on the first weight portion as a first weight film, and any one of weight films 33, 34, 35, and 36 is arranged on the second weight portion as a second weight film.

[0076] Here, it is preferable that the arm portions 241, 251, 261, and 271 each have a shape that is plane-symmetrical with respect to the center plane CP in the thickness direction, thereby making it possible to reduce vibration in the thickness direction due to the shapes of the drive arms 24, 25, 26, and 27.

[0077] The vibration element 1 of this embodiment includes drive arms 24, 25, 26, and 27 that are driven to vibrate, and detection arms 22 and 23 that deform in response to inertial force, and the base 21 has a base main body 211 and connecting arms 212 and 213 that are connecting parts extending from the base main body 211. The drive arms 24, 25, 26, and 27 are vibrating arms that extend from the connecting arms 212 and 213, and the detection arms 22 and 23 extend from the base main body 211. This allows the characteristics of the so-called double-T type vibration element 1 to be improved.

[0078] The width W of the weights 242, 252, 262, and 272 is larger than the width W0 of the arm portions 241, 251, 261, and 271 in a plan view from the thickness direction of the weight 242. This increases the area of ​​the weights 242, 252, 262, and 272 on which weight films 33, 34, 35, and 36 can be formed. Furthermore, the lengths of the drive arms 24, 25, 26, and 27 can be shortened, and as a result, the vibration element 1 can be made smaller.

[0079] Plummet 242 has a first portion 242a and second portions 242b and 242c that are thinner than first portion 242a. Second main surface 2b has stepped portions 244 and 245 formed by first portion 242a and second portions 242b and 242c. This allows center of gravity G1 of plummet 242 to be positioned closer to first main surface 2a than center plane CP in the thickness direction of arm 241 with a relatively simple configuration. Plummets 252, 262, and 272 are configured similarly to plummet 242 and achieve the same effect. Here, "step 244" has a shape in which the average distance from the center plane in the thickness direction of plummet 242 in first portion 242a to second main surface 2b is greater than the average distance from the center plane in the thickness direction of plummet 242 in second portion 242b to second main surface 2b. The "central plane in the thickness direction of weight portion 242" refers to a plane perpendicular to the thickness direction of weight portion 242, where the distance between the outermost point in the thickness direction on the first main surface 2a side of weight portion 242 and the outermost point in the thickness direction on the second main surface 2b side of weight portion 242 is equal. The thickness direction of weight portion 242 and the thickness direction of arm portion 241 are the same. In the illustration, the central plane in the thickness direction of weight portion 242 and the central plane CP in the thickness direction of arm portion 241 are on the same plane. Note that step 245 is defined in the same way as step 244.

[0080] Furthermore, the steps 244, 245 provided on the second main surface 2b described above are configured to include inclined surfaces, and the weight 242 has a portion where the thickness gradually decreases between the first portion 242a and the second portions 242b, 242c in a plan view from the thickness direction of the weight 242. This makes it possible to easily form the weight film 33 continuously across the first portion 242a and the second portions 242b, 242c. It is also possible to reduce the occurrence of cracks in the weight film 33 due to the steps 244, 245 between the first portion 242a and the second portions 242b, 242c. Furthermore, weights 252, 262, and 272 are configured in the same manner as weight 242, and provide the same effects.

[0081] In this embodiment, second portions 242b and 242c are arranged on both sides of first portion 242a in the width direction of drive arm 24 (vibrating arm). This reduces the mass of both ends of weight portion 242 in the width direction, and reduces the torsional moment of drive arm 24. Weight portions 252, 262, and 272 are also configured in the same manner as weight portion 242, and provide the same effects.

[0082] Furthermore, the first main surface 2a of the weight 242 is a flat surface. This eliminates the need to process the first main surface 2a of the weight 242 to provide the first portion 242a and the second portions 242b and 242c in the weight 242, thereby simplifying the manufacturing process of the vibration element 1. The weights 252, 262, and 272 are also configured in the same manner as the weight 242 and achieve the same effects. Note that the first main surface 2a may have a step like the second main surface 2b, but in order to position the center of gravity G1 as described above, it is preferable that the depth of the step on the first main surface 2a be shallower than the depth of the step on the second main surface 2b.

[0083] The weight film 33 is disposed on the first portion 242a and the second portions 242b and 242c. This increases the mass of the weight film 33. Furthermore, the formation of the weight film 33 can be simplified. The weight films 34, 35, and 36 are configured similarly to the weight film 33 and provide similar effects. The weight film 33 may be disposed on only one of the first portion 242a and the second portions 242b and 242c, as long as the center of gravity G2 is located as described above. Providing the weight film 33 only on the first portion 242a has the advantage of making it easier to balance the mass in the width direction of the drive arm 24 compared to providing the weight film 33 only on the second portions 242b and 242c.

[0084] Although the thickness of weight film 33 is uniform in the drawing, it may have multiple portions with different thicknesses. That is, weight film 33 may have a first weight film and a second weight film thinner than the first weight film. In this case, fine and coarse adjustments can be easily made when adjusting the resonance frequency of drive arm 24 by removing a portion of weight film 33 with an energy beam such as a laser. Here, the thick first weight film has a large mass per unit area and is suitable for coarse adjustment (coarse adjustment) of the resonance frequency of drive arm 24. On the other hand, the thin second weight film has a small mass per unit area and is suitable for fine adjustment (fine adjustment) of the resonance frequency of drive arm 24. Furthermore, weight films 34, 35, and 36 can achieve the same effect by being configured in the same way as weight film 33.

[0085] In this embodiment, the case has been described in which the center of gravity of the entire structure consisting of weights 242, 252, 262, 272 and weight membranes 33, 34, 35, 36 is brought closer to center C of drive arms 24, 25, 26, 27, but detection arms 22, 23 may also be configured in the same manner as drive arms 24, 25, 26, 27. In this case, the central planes in the thickness direction of arms 221, 231 are each defined in the same way as the central plane in the thickness direction of arm 241. Weight membranes 31, 32 are each defined in the same way as weight membrane 33.

[0086] (Method of manufacturing vibration element) Hereinafter, a method for manufacturing a vibration element of the present invention will be described using the case of manufacturing the vibration element 1 described above as an example.

[0087] FIG. 6 is a flowchart showing an example of a method for manufacturing a vibration element. The method for manufacturing the vibration element 1 includes a vibration piece forming step S10, an electrode forming step S20, an weight film forming step S30, and a frequency adjusting step S40, as shown in Fig. 6. Each step will be described below in order.

[0088] -Vibration piece forming process S10- FIG. 7 is a cross-sectional view showing a step of preparing a substrate in the vibrating reed forming process. FIG. 8 is a cross-sectional view showing a step of forming a corrosion-resistant film and a resist film in the vibrating reed forming process. FIG. 9 is a cross-sectional view showing a step of forming the outer shape of the vibrating reed in the vibrating reed forming process. FIG. 10 is a cross-sectional view showing a step of removing a part of the corrosion-resistant film in the vibrating reed forming process. FIG. 11 is a cross-sectional view showing a step of forming a groove in the vibrating reed forming process. FIG. 12 is a cross-sectional view showing a step of removing the corrosion-resistant film and the resist film in the vibrating reed forming process. Note that FIGS. 7 to 12 show cross sections corresponding to FIG. 5.

[0089] First, the vibrating element 2 is formed. Specifically, for example, first, a quartz substrate 20 having a first main surface 2a and a second main surface 2b is prepared as shown in Fig. 7. Then, corrosion-resistant films 51 and 52 and resist films 53 and 54 are sequentially formed on both sides of the quartz substrate 20 as shown in Fig. 8. Here, the corrosion-resistant films 51 and 52 are each a laminated film formed by laminating, for example, chromium and gold in this order by vapor deposition, sputtering, or the like, and are resistant to the etching solution used in the outline forming process and groove forming process described below, and are patterned to match the planar view shape (outer shape) of the vibrating bar 2. The resist films 53 and 54 are each a film made of a resist material, are resistant to the etching solution used in the outline forming process and groove forming process described below, and are patterned by exposure and development to match not only the planar view shape (outer shape) of the vibrating bar 2, but also the planar view shapes of the grooves 243 and the second portions 242b and 242c, etc.

[0090] Next, as shown in Fig. 9, the crystal substrate 20 is etched using the corrosion-resistant films 51, 52 and the resist films 53, 54 as masks to obtain a crystal substrate 20A having the same outline as the resonator element 2 (outline forming process). Thereafter, as shown in Fig. 10, the corrosion-resistant film 52 is etched using the resist film 54 as a mask to obtain the corrosion-resistant film 52A. Then, as shown in Fig. 11, the crystal substrate 20A is etched using the corrosion-resistant films 51, 52A and the resist films 53, 54 as masks, and the corrosion-resistant films 51, 52A and the resist films 53, 54 are removed by etching or the like to obtain the resonator element 2 (groove forming process).

[0091] Here, the resonator element 2 may be connected to another portion of the quartz substrate 20A (hereinafter also referred to as a "wafer state"). In this wafer state, the resonator element 2 is connected to another portion of the quartz substrate 20A via a broken portion that is formed to be fragile and has a small width or thickness. In addition, in the wafer state, multiple resonator elements 1 can be formed on the quartz substrate 20A all at once.

[0092] -Electrode formation process S20- FIG. 13 is a cross-sectional view showing the electrode forming step.

[0093] As shown in FIG. 13, the electrode film 4 is formed. More specifically, a metal film is formed uniformly on the surface of the vibrating element 2 by, for example, sputtering. Then, a photoresist is applied, exposed, and developed to obtain a resist mask, and then an etching solution is used to remove the metal film in the portion exposed from the resist mask. In this way, the electrode film 4 is formed.

[0094] -Weight film formation process S30- FIG. 14 is a cross-sectional view showing the weight film forming step. As shown in FIG. 14, the weight film 3 is formed by mask deposition or the like.

[0095] -Frequency adjustment process S40- FIG. 15 is a cross-sectional view showing a frequency adjusting step.

[0096] 15, if necessary, a part of the weight film 3 is removed by energy rays LL. More specifically, if necessary, parts of the weight films 33 to 36 are removed to adjust the frequency of the drive vibration (the resonance frequency of the drive arms 24 to 27) so that the resonance frequencies of the drive arms 24 to 27 are equal to each other. Also, if necessary, parts of the weight films 31 and 32 are removed to adjust the frequency of the detection vibration (the resonance frequency of the detection arms 22 and 23).

[0097] As the energy beam LL, for example, a pulse laser such as YAG, YVO4, or excimer laser, a continuous wave laser such as a carbon dioxide laser, or an ion beam such as a focused ion beam (FIB) or an ion beam figuring (IBF) can be used.

[0098] Such a frequency adjustment step S40 may be performed in a wafer state, or may be performed with the device mounted in a package 11, which will be described later. Furthermore, the frequency adjustment step S40 may be performed multiple times; for example, a first coarse adjustment may be performed in a wafer state, and a second fine adjustment may be performed with the device mounted in the package 11.

[0099] As described above, the manufacturing method of the vibration element 1 includes the steps of forming the base 21 and the drive arm 24 (vibration arm) extending from the base 21, having the first and second main surfaces 2a and 2b, which are opposite sides of the base 21, with the center of gravity G1 located closer to the first main surface 2a than the center plane in the thickness direction (vibration piece forming step S10); forming the weight film 33 on the drive arm 24, with the center of gravity G2 located closer to the second main surface 2b than the center plane in the thickness direction of the drive arm 24 (weight film forming step S30); and adjusting the mass of the weight film 33 to adjust the resonant frequency of the drive arm 24 (frequency adjusting step S40). This manufacturing method of the vibration element 1 can improve the characteristics of the resulting vibration element 1. Here, the "center plane in the thickness direction of the drive arm 24" refers to a plane perpendicular to the thickness direction of the drive arm 24, where the distance between the outermost point on the first main surface 2a side of the drive arm 24 and the outermost point on the second main surface 2b side in the thickness direction is equal. In this embodiment, the mass of weight film 33 is reduced and adjusted by removing a portion of weight film 33 with energy beam LL, but the mass of weight film 33 may be increased and adjusted by forming a film on weight film 33 by a film forming method such as sputtering. The same applies to the resonant frequencies of the other drive arms 25 to 27 and detection arms 22 and 23.

[0100] Second Embodiment Fig. 16 is an enlarged plan view showing the weight portion and weight film of the vibrating arm (driving arm) of the vibrator element according to the second embodiment of the present invention, Fig. 17 is a cross-sectional view taken along line CC in Fig. 16.

[0101] The second embodiment will be described below, focusing on the differences from the previously described embodiment, and similar aspects will not be described. Note that in Figures 16 and 17, the same reference numerals are used for components similar to those in the previously described embodiment. The following description will focus on one drive arm, but the same applies to the other drive arms.

[0102] This embodiment is similar to the first embodiment described above, except that the configuration (shape) of the weight portion is different.

[0103] As shown in Fig. 16, the weight portion 242A of the drive arm 24A included in the vibration element 1A of this embodiment has a first portion 242d connected to the arm portion 241, and a second portion 242e arranged on the opposite side of the arm portion 241 with respect to the first portion 242d. As shown in Fig. 17, the thickness t2 of the second portion 242e is thinner than the thickness t1 of the first portion 242d. Here, the weight film 33 is arranged across the first portion 242d and the second portion 242e.

[0104] According to the present embodiment as described above, the characteristics can be improved in the same way as in the first embodiment.

[0105] In this embodiment, second portion 242e is disposed on the opposite side of first portion 242d from base 21. This allows second portion 242e to be located at the tip of drive arm 24A, which has a large mass effect, and therefore the area of ​​second portion 242e in plan view can be reduced. Another advantage is that the mass balance in the width direction of weight portion 242A is less likely to be disrupted.

[0106] Third Embodiment FIG. 18 is an enlarged plan view showing the weight portion and weight film of the vibrating arm (driving arm) of the vibration element according to the third embodiment of the present invention.

[0107] The third embodiment will be described below, focusing on the differences from the previously described embodiments, and a description of similar points will be omitted. Note that in Fig. 18, the same components as those in the previously described embodiments are denoted by the same reference numerals. Also, the following description will focus on one drive arm, but the same applies to the other drive arms.

[0108] This embodiment is similar to the first embodiment described above, except that the configuration (shape) of the weight portion is different.

[0109] The weight portion 242B of the drive arm 24B included in the vibration element 1B of this embodiment has a configuration that combines the first and second embodiments described above. That is, as shown in FIG. 18 , the weight portion 242B has a first portion 242f connected to the arm portion 241 and a second portion 242g located on both sides in the width direction and on the tip side of the first portion 242f. The thickness of the second portion 242g is thinner than the thickness of the first portion 242f. Here, the weight film 33 is disposed across the first portion 242f and the second portion 242g.

[0110] According to the present embodiment as described above, the characteristics can be improved in the same way as in the first embodiment.

[0111] <Fourth embodiment> Fig. 19 is an enlarged plan view showing the weight portion and weight film of the vibrating arm (driving arm) of the vibrator element according to the fourth embodiment of the present invention, Fig. 20 is a cross-sectional view taken along line BB in Fig. 19.

[0112] The fourth embodiment will be described below, focusing on the differences from the previously described embodiments, and similar aspects will not be described. Note that in Figures 19 and 20, the same components as those in the previously described embodiments are denoted by the same reference numerals. The following description will focus on one drive arm, but the same applies to the other drive arms.

[0113] This embodiment is similar to the first embodiment described above, except that the configuration (shape) of the weight portion is different.

[0114] As shown in Fig. 19, the weight portion 242C of the drive arm 24C included in the vibration element 1C of this embodiment has a frame-shaped first portion 242i connected to the arm portion 241, and a second portion 242h located inside the first portion 242i. As shown in Fig. 20, the thickness t2 of the second portion 242h is thinner than the thickness t1 of the first portion 242i. Here, the weight film 33 is disposed across the first portion 242i and the second portion 242h in the width direction of the weight portion 242C.

[0115] According to the present embodiment as described above, the characteristics can be improved in the same way as in the first embodiment.

[0116] In this embodiment, first portion 242i is provided to surround second portion 242h in a plan view from the thickness direction of weight portion 242C. Such second portion 242h is provided by forming recess 247. Recess 247 can be formed by etching, similar to groove 243 described above. This makes it easy to design second portion 242h.

[0117] Fifth Embodiment FIG. 21 is a plan view showing a vibration element according to a fifth embodiment of the present invention.

[0118] The fifth embodiment will be described below, focusing on the differences from the previous embodiments, and omitting a description of similar points.

[0119] This embodiment is similar to the first embodiment described above, except that the present invention is applied to a so-called H-shaped vibration element.

[0120] 21 is a sensor element that detects angular velocity around the y-axis. This vibration element 1D includes a vibration element 2D, and an electrode film (not shown) and a weight film 3D that are provided on the vibration element 2D.

[0121] The vibrating element 2D has a base 21D, a pair of drive arms 24D and 25D, and a pair of detection arms 22D and 23D. These are integrally configured and formed using a Z-cut quartz crystal plate. The correspondence between the crystal axes of the quartz crystal and the x-, y-, and z-axes is the same as in the first embodiment.

[0122] The base 21D is supported by a package 11, which will be described later. Drive arms 24D, 25D each extend in the y-axis direction (+y direction) from base 21D. Drive arms 24D, 25D are configured in the same manner as the drive arms of any of the first to fourth embodiments described above. Although not shown, drive arms 24D, 25D each have a pair of drive electrodes (a drive signal electrode and a drive ground electrode) that, like drive arms 24 to 27 of the first embodiment described above, cause drive arms 24D, 25D to flexurally vibrate in the x-axis direction when current is applied. The pair of drive electrodes are electrically connected to terminals (not shown) on the base portion 21D via wiring (not shown).

[0123] Detection arms 22D and 23D each extend in the y-axis direction (-y direction) from base 21D. Although not shown, detection arms 22D and 23D are each provided with a pair of detection electrodes (a detection signal electrode and a detection ground electrode) that detect electric charges generated in association with bending vibration of detection arms 22D and 23D in the z-axis direction. This pair of detection electrodes is electrically connected to terminals (not shown) on base 21D via wiring (not shown).

[0124] The weight film 3D has weight films 31D and 32D arranged on the tip portions (weight portions) of the detection arms 22D and 23D, and weight films 33D and 34D arranged on the tip portions (weight portions) of the drive arms 24D and 25D.

[0125] In the vibration element 1D configured in this manner, when a drive signal is applied between a pair of drive electrodes, the drive arms 24D and 25D undergo bending vibration (drive vibration) so as to repeatedly approach and move away from each other, as shown by arrows A1 and A2 in Figure 21.

[0126] When an angular velocity ω about the y-axis is applied to the vibration element 1D while the drive arms 24D and 25D are driven to vibrate in this manner, the Coriolis force causes the drive arms 24D and 25D to flex and vibrate in opposite directions in the z-axis direction, as shown by arrows B1 and B2 in Fig. 21. Accordingly, the detection arms 22D and 23D flex and vibrate (detection vibration) in opposite directions in the z-axis direction, as shown by arrows C1 and C2 in Fig. 21.

[0127] The flexural vibration of the detection arms 22D and 23D generates electric charges between the pair of detection electrodes, which are output from the pair of detection electrodes. Based on these electric charges, the angular velocity ω applied to the vibration element 1D can be determined.

[0128] According to the present embodiment as described above, the characteristics can be improved in the same way as in the first embodiment.

[0129] Here, the vibration element 1D of this embodiment includes drive arms 24D and 25D that extend from a base 21D and are driven to vibrate, and detection arms 22D and 23D that extend from the base 21D in the opposite direction to the drive arms 24D and 25D and deform in response to inertial force, where the drive arms 24D and 25D are vibrating arms. This allows the characteristics of the so-called H-shaped vibration element 1D to be improved.

[0130] Sixth Embodiment FIG. 22 is a plan view showing a vibration element according to a sixth embodiment of the present invention.

[0131] The sixth embodiment will be described below, focusing on the differences from the previous embodiments, and omitting a description of similar points.

[0132] This embodiment is similar to the first embodiment described above, except that the present invention is applied to a so-called two-prong tuning fork type vibration element.

[0133] 22 is a sensor element that detects angular velocity around the y-axis. This vibration element 1E includes a vibration reed 2E, and an electrode film (not shown) and weight films 33E and 34E provided on the vibration reed 2E.

[0134] The vibrating element 2E has a base 21E and a pair of vibrating arms 24E and 25E, which are integrally formed using a Z-cut quartz crystal plate. The correspondence between the crystal axes of the quartz crystal and the x-, y-, and z-axes is the same as in the first embodiment.

[0135] The base 21E includes a first base 214 to which the vibrating arms 24E and 25E are connected, a second base 216 disposed on the opposite side of the first base 214 from the vibrating arms 24E and 25E, and a connecting portion 215 connecting the first base 214 and the second base 216. The connecting portion 215 is located between the first base 214 and the second base 216 and has a smaller width (length in the x-axis direction) than the first base 214. This allows the length of the base 21E along the y-axis direction to be reduced while also reducing vibration leakage. Here, the second base 216 is supported by, for example, a package 11, which will be described later.

[0136] The vibrating arms 24E and 25E each extend from the base 21E in the y-axis direction (+y direction). The vibrating arms 24E and 25E are configured in the same manner as the drive arms of any of the first to fourth embodiments described above. Although not shown, each of the vibrating arms 24E and 25E is provided with a pair of drive electrodes (a drive signal electrode and a drive ground electrode) that, when energized, causes the vibrating arms 24E and 25E to flexurally vibrate in the x-axis direction, similar to the drive arms 24 to 27 of the first embodiment described above. The pair of drive electrodes are electrically connected to terminals (not shown) on the base 21E via wiring (not shown).

[0137] In addition to the pair of drive electrodes described above, each of the vibrating arms 24E and 25E is provided with a pair of detection electrodes (a detection signal electrode and a detection ground electrode), not shown, that detect electric charges generated in association with the bending vibration of the vibrating arms 24E and 25E in the z-axis direction. This pair of detection electrodes is electrically connected to a terminal (not shown) on the base 21E via wiring not shown.

[0138] The weight films 33E and 34E are disposed on the tips (weight portions) of the vibrating arms 24E and 25E. In the vibrating element 1E configured in this manner, when a drive signal is applied between the pair of drive electrodes, the vibrating arms 24E and 25E undergo bending vibration (drive vibration) so as to repeatedly approach and move away from each other.

[0139] When an angular velocity ω about the y-axis is applied to the vibration element 1E while the vibrating arms 24E and 25E are driven to vibrate in this manner, the Coriolis force excites the vibration arms 24E and 25E to vibrate in opposite directions along the z-axis. Then, charges generated between the pair of detection electrodes due to this excited vibration are output from the pair of detection electrodes. The angular velocity ω applied to the vibration element 1E can be calculated based on these charges.

[0140] According to the present embodiment as described above, the characteristics can be improved in the same way as in the first embodiment.

[0141] 2. Physical quantity sensors FIG. 23 is a cross-sectional view showing a physical quantity sensor according to an embodiment of the present invention.

[0142] 23 is a vibration gyro sensor that detects angular velocity around the z-axis. This physical quantity sensor 10 has a vibration element 1 (or 1A, 1B, 1C, 1D, or 1E), a support member 12, a circuit element 13 (an integrated circuit chip), and a package 11 that houses these elements.

[0143] The package 11 has a box-shaped base 111 having a recess for accommodating the vibration element 1, and a plate-shaped lid 112 joined to the base 111 via a joining member 113 so as to close the opening of the recess of the base 111. The inside of the package 11 may be in a reduced pressure (vacuum) state, or may be filled with an inert gas such as nitrogen, helium, or argon.

[0144] The recess of the base 111 has an upper surface located on the opening side, a lower surface located on the bottom side, and a middle surface located between these surfaces. The material of the base 111 is not particularly limited, but various ceramics such as aluminum oxide and various glass materials can be used. The material of the lid 112 is also not particularly limited, but it is preferable that the material has a linear expansion coefficient similar to that of the material of the base 111. For example, if the material of the base 111 is a ceramic such as those described above, it is preferable that the material be an alloy such as Kovar. Furthermore, in this embodiment, a seam ring is used as the joining member 113, but the joining member 113 may be made of, for example, low-melting-point glass, adhesive, or the like.

[0145] A plurality of connection terminals 14, 15 are provided on the upper and middle surfaces of the recess of base 111. Some of the plurality of connection terminals 15 provided on the middle surface are electrically connected to terminals 16 provided on the bottom surface of base 111 via a wiring layer (not shown) provided on base 111, and the remaining are electrically connected to the plurality of connection terminals 14 provided on the upper surface via wiring (not shown). These connection terminals 14, 15 are not particularly limited as long as they are conductive, but may be formed, for example, of a metal coating formed by laminating coatings of Ni (nickel), Au (gold), Ag (silver), Cu (copper), etc. on a metallized layer (underlayer) of Cr (chromium), W (tungsten), etc.

[0146] The circuit element 13 is fixed to the lower surface of the recess in the base 111 with an adhesive 19 or the like. For example, an epoxy-based, silicone-based, or polyimide-based adhesive can be used as the adhesive 19. The circuit element 13 has a plurality of terminals (not shown), each of which is electrically connected to each of the connection terminals 15 provided on the middle surface by a conductive wire. The circuit element 13 has a drive circuit for driving the vibration element 1 to vibrate, and a detection circuit for detecting the detection vibration generated in the vibration element 1 when an angular velocity is applied.

[0147] Furthermore, a support member 12 is connected to a plurality of connection terminals 14 provided on the upper surface of the recess of base 111 via a conductive adhesive 17. Support member 12 has a wiring pattern 122 connected to the conductive adhesive 17 and a support substrate 121 that supports wiring pattern 122. As the conductive adhesive 17, for example, an epoxy-based, silicone-based, or polyimide-based conductive adhesive mixed with a conductive material such as a metal filler can be used.

[0148] The support substrate 121 has an opening in the center, and a plurality of long leads of the wiring pattern 122 extend into the opening. The vibrating element 1 is connected to the tip ends of these leads via conductive bumps 123.

[0149] In this embodiment, the circuit element 13 is provided inside the package 11, but the circuit element 13 may be provided outside the package 11.

[0150] As described above, the physical quantity sensor 10 includes the resonator element 1 (or 1A, 1B, 1C, 1D, or 1E) and the package 11 that houses the resonator element 1 (or 1A, 1B, 1C, 1D, or 1E). Such a physical quantity sensor 10 can utilize the excellent characteristics of the resonator element 1 (or 1A, 1B, 1C, 1D, or 1E) to improve the sensor characteristics (e.g., detection accuracy) of the physical quantity sensor 10.

[0151] 3. Inertial Measurement Unit Fig. 24 is an exploded perspective view showing an embodiment of an inertial measurement unit of the present invention, and Fig. 25 is a perspective view of a board provided in the inertial measurement unit shown in Fig. 24.

[0152] The inertial measurement unit (IMU) 2000 shown in Figure 24 is a so-called six-axis motion sensor that is attached to a moving body (object to be measured) such as an automobile or robot, and detects the posture and behavior (inertial momentum) of the moving body.

[0153] This inertial measurement unit 2000 includes an outer case 2100, a joint member 2200, and a sensor module 2300, and the sensor module 2300 is fitted (inserted) into the outer case 2100 with the joint member 2200 interposed therebetween.

[0154] The outer case 2100 is box-shaped, and has screw holes 2110 at two diagonal corners of the outer case 2100 for screwing the outer case 2100 into the object to be measured.

[0155] The sensor module 2300 includes an inner case 2310 and a substrate 2320, and is housed inside the outer case 2100 described above, with the inner case 2310 supporting the substrate 2320. Here, the inner case 2310 is joined to the outer case 2100 by adhesive or the like via a joining member 2200 (e.g., a rubber packing). The inner case 2310 also has a recess 2311 that functions as a storage space for components mounted on the substrate 2320, and an opening 2312 for exposing a connector 2330 provided on the substrate 2320 to the outside. The substrate 2320 is, for example, a multilayer wiring board, and is joined to the inner case 2310 by adhesive or the like.

[0156] As shown in FIG. 25, a connector 2330, angular velocity sensors 2340X, 2340Y, and 2340Z, an acceleration sensor 2350, and a control IC 2360 are mounted on a substrate 2320.

[0157] The connector 2330 is electrically connected to an external device (not shown) and is used to transmit and receive electrical signals such as power and measurement data between the external device and the inertial measurement unit 2000 .

[0158] Angular velocity sensor 2340X detects angular velocity around the X-axis, angular velocity sensor 2340Y detects angular velocity around the Y-axis, and angular velocity sensor 2340Z detects angular velocity around the Z-axis. Here, angular velocity sensors 2340X, 2340Y, and 2340Z are each the above-mentioned physical quantity sensor 10. Furthermore, acceleration sensor 2350 is, for example, an acceleration sensor formed using MEMS technology, and detects acceleration in each of the X-axis, Y-axis, and Z-axis directions.

[0159] Control IC 2360 is an MCU (Micro Controller Unit) that has built-in storage including nonvolatile memory, an A / D converter, etc., and controls each part of inertial measurement unit 2000. The storage stores a program that defines the order and content for detecting acceleration and angular velocity, a program that digitizes the detected data and incorporates it into packet data, and accompanying data.

[0160] As described above, the inertial measurement unit 2000 includes the physical quantity sensor 10 and the control IC 2360, which is a circuit electrically connected to the physical quantity sensor 10. With such an inertial measurement unit 2000, the excellent sensor characteristics of the physical quantity sensor 10 can be utilized to improve the characteristics (e.g., measurement accuracy) of the inertial measurement unit 2000.

[0161] 4.Electronic equipment FIG. 26 is a perspective view showing an embodiment of an electronic device of the present invention (a mobile (or notebook) personal computer).

[0162] 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 1108, and the display unit 1106 is rotatably supported on the main body 1104 via a hinge structure. Such a personal computer 1100 incorporates an inertial measurement unit 2000 including the above-mentioned vibration element 1 (or 1A, 1B, 1C, 1D, or 1E).

[0163] FIG. 27 is a plan view showing an embodiment (mobile phone) of an electronic device of the present invention. In this figure, mobile phone 1200 includes an antenna (not shown), a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206, and a display unit 1208 is disposed between operation buttons 1202 and earpiece 1204. Such mobile phone 1200 incorporates an inertial measurement unit 2000 including the above-described vibration element 1 (or 1A, 1B, 1C, 1D, or 1E).

[0164] FIG. 28 is a perspective view showing an embodiment (digital still camera) of an electronic device of the present invention.

[0165] A display unit 1310 is provided on the back of a case 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 1310 functions as a viewfinder that displays an electronic image of the subject. A light receiving unit 1304, including an optical lens (image capturing optical system) and a CCD, is provided on the front side (the back side in the figure) of the case 1302. When the photographer checks the subject image displayed on the display unit 1310 and presses the shutter button 1306, the image signal captured by the CCD at that time is transferred to and stored in memory 1308. This digital still camera 1300 incorporates an inertial measurement unit 2000 that includes the vibration element 1 (or 1A, 1B, 1C, 1D, or 1E) described above. The measurement results of this inertial measurement unit 2000 are used, for example, for image stabilization.

[0166] The electronic device as described above includes the vibration element 1 (or 1A, 1B, 1C, 1D, or 1E). According to such an electronic device, the excellent characteristics of the vibration element 1 (or 1A, 1B, 1C, 1D, or 1E) can be utilized to improve the characteristics (e.g., reliability) of the electronic device.

[0167] In addition to the personal computer of FIG. 26, the mobile phone of FIG. 27, and the digital still camera of FIG. 28, the electronic device of the present invention can be applied to, for example, smartphones, tablet terminals, watches (including smart watches), inkjet discharge devices (e.g., inkjet printers), wearable terminals such as HMDs (head-mounted displays), 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 equipment (e.g., electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasound diagnostic devices, and electronic endoscopes), fish finders, various measuring instruments, instruments (e.g., instruments for vehicles, aircraft, and ships), base stations for mobile terminals, flight simulators, and the like.

[0168] 5. Mobile FIG. 29 is a perspective view showing an embodiment of a moving body (automobile) of the present invention.

[0169] An inertial measurement unit 2000 including the above-described vibration element 1 (or 1A, 1B, 1C, 1D, or 1E) is built into automobile 1500, and, for example, the attitude of vehicle body 1501 can be detected by inertial measurement unit 2000. A detection signal from inertial measurement unit 2000 is supplied to vehicle body attitude control device 1502, which detects the attitude of vehicle body 1501 based on the signal, and can control the hardness or softness of the suspension or the brakes on individual wheels 1503 according to the detection result.

[0170] In addition, such attitude control can be used in bipedal robots and radio-controlled helicopters (including drones). As described above, the inertial measurement unit 2000 is incorporated to realize attitude control of various moving bodies.

[0171] As described above, automobile 1500, which is a moving object, is equipped with vibration element 1 (or 1A, 1B, 1C, 1D, 1E). With such automobile 1500, the excellent characteristics of vibration element 1 (or 1A, 1B, 1C, 1D, 1E) can be utilized to improve the characteristics (e.g., reliability) of automobile 1500.

[0172] While the vibration element, the vibration element manufacturing method, the physical quantity sensor, the inertial measurement unit, the electronic device, and the moving object of the present invention have been described above based on the illustrated embodiments, the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration having a similar function. In addition, any other configuration may be added to the present invention.

[0173] Furthermore, in the above-described embodiments, the vibration element has a so-called double T-type, H-type, or two-legged tuning fork shape, but is not limited to this and may have various shapes such as a tripod tuning fork, an orthogonal type, or a rectangular prism type, as long as the element has vibrating arms that vibrate in an in-plane direction. [Explanation of symbols]

[0174] 1...vibration element, 1A...vibration element, 1B...vibration element, 1C...vibration element, 1D...vibration element, 1E...vibration element, 2...vibration piece, 2D...vibration piece, 2E...vibration piece, 2a...first main surface, 2b...second main surface, 3...weight film, 3D...weight film, 4...electrode film, 10...physical quantity sensor, 11...package, 12...support member, 13...circuit element, 14...connection terminal, 15...connection terminal, 16...terminal, 17...conductive adhesive, 19...adhesive, 20...quartz substrate, 20A...quartz substrate, 21...base, 21D...base, 21E...base, 22...detection arm, 22D...detection arm, 23...detection arm, 23D...detection arm, 24...drive Arm, 24A... driving arm, 24B... driving arm, 24C... driving arm, 24D... driving arm, 24E... vibrating arm, 25... driving arm, 25D... driving arm, 25E... vibrating arm, 26... driving arm, 27... driving arm, 31... weight film, 31D... weight film, 32... weight film, 32D... weight film, 33... weight film, 33D... weight film, 33E... weight film, 34... weight film, 34D... weight film, 34E... weight film, 35... weight film, 36... weight film, 41... driving signal electrode, 42... driving ground electrode, 43... detection signal electrode, 44... detection ground electrode, 51... corrosion-resistant film, 52... corrosion-resistant film, 52A... corrosion-resistant film, 53... resist film, 54... resist film, 111... base, 11 2...lid, 113...bonding member, 121...support substrate, 122...wiring pattern, 123...bump, 211...base main body, 212...connecting arm, 213...connecting arm, 214...first base, 215...connecting portion, 216...second base, 221...arm portion, 222...weight portion, 223...groove, 231...arm portion, 232...weight portion, 233...groove, 241...arm portion, 242...weight portion, 242A...weight portion, 242B...weight portion, 242C...weight portion, 242a...first portion, 242b...second portion, 242c...second portion, 242d...first portion, 242e...second portion, 242f...first portion, 242g...second portion, 242h... Second part, 242i...first part, 243...groove, 244...step, 245...step, 247...recess, 251...arm, 252...weight, 253...groove, 261...arm, 262...weight, 263...groove, 271...arm, 272...weight, 273...groove, 1100...personal computer, 1102...keyboard, 1104...main body, 1106...display unit, 1108...display, 1200...mobile phone, 1202...operation buttons, 1204...earpiece, 1206...mouthpiece, 1208...display, 1300...digital still camera, 1302...case, 1304...light receiving unit,1306...shutter button, 1308...memory, 1310...display unit, 1500...automobile, 1501...vehicle body, 1502...vehicle body attitude control device, 1503...wheel, 2000...inertial measurement unit, 2100...outer case, 2110...screw hole, 2200...joint member, 2300...sensor module, 2310...inner case, 2311...recess, 2312...opening, 2320...board, 2330...connector, 2340X...angular velocity sensor sensor, 2340Y...angular velocity sensor, 2340Z...angular velocity sensor, 2350...acceleration sensor, 2360...control IC, A1...arrow, A2...arrow, B1...arrow, B2...arrow, C...center, C1...arrow, C2...arrow, G...center of gravity, G1...center of gravity, G2...center of gravity, LL...energy ray, S10...vibrator element forming process, S20...electrode forming process, S30...weight film forming process, S40...frequency adjustment process, a...arrow, b...arrow, c...arrow, ω...angular velocity,

Claims

1. A base and a vibrating arm extending from the base and having an arm portion located on the base side and a weight portion located on the tip side of the arm portion; a weight membrane disposed on the weight portion, the weight portion has a first main surface and a second main surface which are opposite surfaces, the center of gravity of the weight portion is located on the first main surface side of the center plane of the arm portion in the thickness direction, A vibration element characterized in that the center of gravity of the weight film is located at a position closer to the second main surface than the center plane of the arm in the thickness direction.

2. The vibration element according to claim 1, wherein the weight portion has a first portion and a second portion that is thinner than the first portion, and the second main surface has a stepped shape due to the first portion and the second portion.

3. The vibration element according to claim 2 , wherein the weight portion has a portion between the first portion and the second portion, the thickness of which gradually decreases in plan view from the thickness direction of the weight portion.

4. The vibration element according to claim 2 , wherein the width of the weight portion is larger than the width of the arm portion in a plan view in the thickness direction.

5. The vibration element according to claim 2 , wherein the second portions are disposed on both sides of the first portion in the width direction of the vibration arm.

6. The vibration element according to claim 2 , wherein the second portion is disposed on an opposite side of the first portion from the base portion.

7. The vibration element according to claim 2 , wherein the first portion is provided to surround the second portion in a plan view from a thickness direction of the weight portion.

8. The vibration element according to claim 2 , wherein the first main surface is a flat surface.

9. The vibration element according to claim 2 , wherein the weight film is disposed on the first portion and the second portion.

10. The vibration element according to claim 1 , wherein the arm portion has a shape that is plane-symmetrical with respect to a center plane in the thickness direction of the arm portion.

11. a first vibrating arm extending from the base and having a first arm portion serving as the arm portion and a first weight portion serving as the weight portion; a second vibrating arm extending from the base and having a second arm located on the base side and a second weight located on a tip side of the second arm; a first weight film that is the weight film disposed on the first weight portion; a second weight film disposed on the second weight portion, a center of gravity of the second weight portion is located at a position closer to the first main surface than a central plane of the second arm portion in a thickness direction, The vibration element according to claim 1 , wherein the center of gravity of the second weight film is located closer to the second main surface than the center plane of the second arm in the thickness direction.

12. A driving arm that vibrates, a detection arm that deforms in response to an inertial force; The base includes a base body and a connecting portion extending from the base body, the driving arm is the vibrating arm and extends from the connecting portion; The vibrating element according to claim 1 , wherein the detection arm extends from the base body.

13. a driving arm extending from the base and drivingly vibrating; a detection arm extending from the base in a direction opposite to the drive arm and deforming in response to an inertial force; The vibration element according to claim 1 , wherein the driving arm is the vibrating arm.

14. The vibration element according to claim 1 , wherein the weight film includes a first weight film and a second weight film that is thinner than the first weight film.

15. forming a base and a vibrating arm extending from the base, having a first main surface and a second main surface that are opposite sides of the base, and having a center of gravity located on the first main surface side of a central plane in a thickness direction; forming a weight film on the vibrating arm, the weight film having a center of gravity located on the second main surface side of a center plane in a thickness direction of the vibrating arm; and adjusting the mass of the weight film to adjust the resonance frequency of the vibrating arm.

16. The vibration element according to any one of claims 1 to 14, a package that houses the vibration element.

17. The physical quantity sensor according to claim 16 ; a circuit electrically connected to the physical quantity sensor.

18. An electronic device comprising the vibration element according to claim 1 .

19. A moving body comprising the vibration element according to any one of claims 1 to 14.

Images