Resonator and resonator device

Abstract

The present application provides a resonator and a resonant device capable of further improving DLD. The resonator (10) comprises: a vibration portion (110) including a plurality of vibration arms (121A)-(121D) and a base portion (130), the plurality of vibration arms (121A)-(121D) are three or more and each has a fixed end, at least two of the vibration arms are out-of-plane bending at different phases, the base portion (130) has a front end portion (131A) to which the fixed end of each of the plurality of vibration arms (121A)-(121D) is connected and a rear end portion (131B) opposite to the front end portion (131A); a holding portion (140) configured to hold the vibration portion (110); and a support arm (151A) having one end connected to the holding portion (140) and the other end connected to the rear end portion (131B) of the base portion (130), the support arm (151A) is asymmetric about a center line (CL1) of a long side direction of the vibration portion (110) when viewed from above.

Description

Technical Field

[0001] This invention relates to a resonator and a resonator device for multiple vibrating arms vibrating in an out-of-plane bending vibration mode. Background Technology

[0002] Previously, resonant devices using MEMS (Micro Electro Mechanical Systems) technology have been used, for example, as timing devices. These resonant devices are mounted on printed circuit boards incorporated into electronic devices such as smartphones. The resonant device includes: a lower substrate, an upper substrate forming a cavity between the lower substrate and the upper substrate, and a resonator disposed within the cavity between the lower and upper substrates.

[0003] For example, Patent Document 1 discloses a resonator having multiple vibrating arms. This resonator includes: a vibrating part having a base and multiple vibrating arms, wherein the base has a front end and a rear end opposite to the front end, and the fixed ends of the multiple vibrating arms are connected to the front end of the base and extend in a direction away from the front end; a holding part being disposed around at least a portion of the vibrating part; and a holding arm being disposed between the vibrating part and the holding part, one end being connected to the base, and the other end being connected to a region in the holding part closer to the front end than the rear end of the base. In the resonator of Patent Document 1, the connection position of the holding arm to the base is made to be less than 60% of half the length of the base, thereby improving the drive-level dependence (DLD) characteristic (hereinafter referred to as "DLD").

[0004] Patent document 1: International Publication No. 2016 / 175218.

[0005] Furthermore, in recent years, the demand for miniaturization of resonators has become increasingly stringent. In resonators whose size is limited by miniaturization, as in Patent Document 1, it is difficult to continuously improve the DLD simply by making the length of the holding arm connection position relative to the base length less than a specified ratio. Summary of the Invention

[0006] The present invention was made in view of the following circumstances, and one of its objectives is to provide a resonator and resonant device that can further improve DLD.

[0007] One aspect of the present invention relates to a resonator comprising: a vibrating part including a plurality of vibrating arms and a base, wherein the plurality of vibrating arms are three or more and each has a fixed end, at least two of which are bent out of plane at different phases, the base having one end for connection to the fixed end of each of the plurality of vibrating arms and another end opposite to the fixed end; a holding part configured to hold the vibrating part; and a support arm having one end connected to the holding part and the other end connected to the other end of the base, the support arm being asymmetrical about the centerline of the long side direction of the vibrating part when viewed from above.

[0008] Another aspect of the present invention relates to a resonator comprising: a vibrating part including a plurality of vibrating arms and a base, wherein the plurality of vibrating arms are three or more and each has a fixed end, at least two of which are bent out of plane at different phases, the base having one end for connecting to the fixed end of each of the plurality of vibrating arms, another end opposite to the fixed end, and a side end; a holding part configured to hold the vibrating part; and a support arm having one end connected to the holding part and the other end connected to the side end of the base, the support arm extending from one side to the other about the center line of the long side direction of the vibrating part when viewed from above, and the other end of the support arm connected to the side end of the base on the other side.

[0009] One aspect of the resonant device relates to the present invention includes the resonator described above.

[0010] According to the present invention, DLD can be further improved. Attached Figure Description

[0011] Figure 1 This is a perspective view that briefly shows the appearance of the resonant device in the first embodiment.

[0012] Figure 2 It is a brief representation Figure 1 An exploded perspective view of the structure of the resonant device shown.

[0013] Figure 3 It is a brief representation Figure 2 The diagram shows a top view of the construction of a harmonic oscillator.

[0014] Figure 4 It is a brief representation Figure 1 A cross-sectional view along the X-axis of the stacked structure of the resonant device shown.

[0015] Figure 5 It is a conceptual representation Figure 1 A cross-sectional view along the Y-axis of the stacked structure of the resonant device shown.

[0016] Figure 6 It is a schematic representation based on Figure 3 A top view of the displacement distribution of the vibrating part shown.

[0017] Figure 7 It is a schematic representation based on Figure 3 A three-dimensional diagram showing the displacement distribution of the vibrating part.

[0018] Figure 8 It means based on Figure 3 The diagram shows the displacement of the base of the vibrating part.

[0019] Figure 9 This is a top view that briefly shows the construction of the harmonic oscillator in the first variation of the first embodiment.

[0020] Figure 10 This is a top view that briefly illustrates the construction of the harmonic oscillator in the second variation of the first embodiment.

[0021] Figure 11 It means based on Figure 9 and Figure 10 The diagram shows the displacement of the base of the vibrating part.

[0022] Figure 12 It means Figure 3 , Figure 9 as well as Figure 10 The graph shows the relationship between power and frequency variation rate at each connection point of the support arm on the base.

[0023] Figure 13 It means Figure 3 , Figure 9 as well as Figure 10 The graph shows the relationship between the connection position of the support arm on the base and the rate of change of frequency per unit power.

[0024] Figure 14 This is a top view that briefly illustrates the construction of the harmonic oscillator in the third variation of the first embodiment.

[0025] Figure 15 It is used for explanation Figure 3 A top view showing the dimensions of the vibrating part.

[0026] Figure 16 This is a top view that briefly illustrates the construction of the harmonic oscillator in the second embodiment.

[0027] Figure 17 This is a top view that briefly illustrates the construction of the harmonic oscillator in the first variation of the second embodiment.

[0028] Figure 18 This is a top view that briefly illustrates the construction of the harmonic oscillator in the second variation of the second embodiment.

[0029] Figure 19This is a top view that briefly illustrates the construction of the harmonic oscillator in the third variation of the second embodiment.

[0030] Figure 20 This is a top view that briefly illustrates the construction of the harmonic oscillator in the fourth variation of the second embodiment.

[0031] Figure 21 This is a top view that briefly illustrates the construction of the harmonic oscillator in the fifth variation of the second embodiment. Detailed Implementation

[0032] The embodiments of the present invention will be described below. In the following drawings, the same or similar reference numerals denote the same or similar constituent elements. The drawings are illustrative, and the dimensions and shapes of the parts are schematic; the scope of the present invention should not be limited to these embodiments.

[0033] [First Implementation Method]

[0034] First, refer to Figure 1 and Figure 2 A brief description of the structure of the resonant device according to the first embodiment will be provided. Figure 1 This is a perspective view that briefly shows the appearance of the resonant device 1 in the first embodiment. Figure 2 It is a brief representation Figure 1 An exploded perspective view of the structure of the resonant device 1 shown.

[0035] The resonant device 1 includes a lower cover 20, a resonator 10, and an upper cover 30. That is, the resonant device 1 is constructed by sequentially stacking the lower cover 20, the resonator 10, and the upper cover 30 in that order. The lower cover 20 and the upper cover 30 are arranged opposite each other with a gap between them and the resonator 10. Furthermore, the lower cover 20 and the upper cover 30 are an example of the "cover" of the present invention.

[0036] The structure of the resonant device 1 will be described below. In the following description, the side of the resonant device 1 with the upper cover 30 will be referred to as the upper (or front) and the side with the lower cover 20 will be referred to as the lower (or back).

[0037] The resonator 10 is a MEMS oscillator manufactured using MEMS technology. The resonator 10, lower cover 20, and upper cover 30 are joined together to seal the resonator 10 and form the vibration space of the resonator 10. Furthermore, the resonator 10, lower cover 20, and upper cover 30 are each formed using a silicon (Si) substrate (hereinafter referred to as "Si substrate"), and the Si substrates are bonded together. Alternatively, the resonator 10, lower cover 20, and upper cover 30 can also be formed using an SOI (Silicon On Insulator) substrate with a silicon layer and a silicon oxide film stacked on it.

[0038] The lower cover 20 includes: a rectangular flat plate 22 disposed along the XY plane, and a sidewall 23 extending from the periphery of the base plate 22 toward the Z-axis direction, i.e., the stacking direction of the lower cover 20 and the resonator 10. A recess 21, defined by the surface of the base plate 22 and the inner surface of the sidewall 23, is formed on the surface of the lower cover 20 opposite to the resonator 10. The recess 21 forms at least a portion of the vibration space of the resonator 10. Alternatively, the lower cover 20 may also be a flat plate structure without the recess 21. Furthermore, an air-absorbing layer may be formed on the resonator 10 side surface of the recess 21 of the lower cover 20.

[0039] In addition, the lower cover 20 has a protrusion 50 formed on the surface of the base plate 22. The detailed structure of the protrusion 50 will be described later.

[0040] The top cover 30 includes: a rectangular flat base plate 32 disposed along the XY plane, and a sidewall 33 extending from the periphery of the base plate 32 in the Z-axis direction. A recess 31, defined by the surface of the base plate 32 and the inner surface of the sidewall 33, is formed on the surface of the top cover 30 opposite to the resonator 10. The recess 31 forms at least a portion of the space in which the resonator 10 vibrates. Alternatively, the top cover 30 may be a flat plate structure without the recess 31. Furthermore, an air-absorbing layer may be formed on the surface of the top cover 30 on the resonator 10 side of the recess 31.

[0041] By joining the upper cover 30, the resonator 10, and the lower cover 20, the vibration space of the resonator 10 is hermetically sealed, maintaining a vacuum state. Alternatively, the vibration space can be filled with a gas such as an inert gas.

[0042] Next, refer to Figure 3 A brief description of the structure of the harmonic oscillator according to the first embodiment is provided. Figure 3 It is a brief representation Figure 2 The diagram shows a top view of the structure of the harmonic oscillator 10.

[0043] like Figure 3 As shown, the resonator 10 is a MEMS oscillator manufactured using MEMS technology. Figure 3 The vibration occurs primarily in the XY plane of the orthogonal coordinate system, with out-of-plane bending vibration as the dominant vibration mode (hereinafter also referred to as the "dominant mode").

[0044] The resonator 10 includes a oscillating part 110, a holding part 140, and a supporting arm part 150.

[0045] The vibrating part 110 has a longitudinal direction Figure 3 The outline of a rectangle extended from the XY plane in an orthogonal coordinate system. The vibrating part 110 is disposed inside the holding part 140, and a space is formed between the vibrating part 110 and the holding part 140 at a predetermined interval. Figure 3 In this example, the vibration unit 110 includes an excitation unit 120 composed of four vibration arms 121A to 121D (hereinafter collectively referred to as "vibration arms 121") and a base 130. Furthermore, the number of vibration arms is not limited to four; for example, it can be any number of three or more. In this embodiment, the excitation unit 120 and the base 130 are integrally formed.

[0046] Vibrating arms 121A, 121B, 121C, and 121D extend along the Y-axis and are arranged side-by-side at predetermined intervals in the X-axis direction in this order. One end of vibrating arm 121A is a fixed end connected to the front end portion 131A of the base 130 (described later), and the other end of vibrating arm 121A is an open end located away from the front end portion 131A of the base 130. Vibrating arm 121A includes a mass attachment portion 122A formed on the open end side and an arm portion 123A extending from the fixed end and connected to the mass attachment portion 122A. Similarly, vibrating arms 121B, 121C, and 121D also include mass attachment portions 122B, 122C, and 122D, and arm portions 123B, 123C, and 123D, respectively. Furthermore, the arm portions 123A to 123D are, for example, approximately 30 μm wide in the X-axis direction and approximately 400 μm long in the Y-axis direction.

[0047] In the excitation unit 120 of this embodiment, two vibrating arms 121A and 121D are arranged on the outer side in the X-axis direction, and two vibrating arms 121B and 121C are arranged on the inner side. The width of the gap (hereinafter referred to as "release width") W1 between the arm portions 123B and 123C of the two inner vibrating arms 121B and 121C is, for example, set to be greater than the release width W2 between the arm portions 123A and 123B of the adjacent vibrating arms 121A and 121B in the X-axis direction, and the release width W2 between the arm portions 123D and 123C of the adjacent vibrating arms 121D and 121C in the X-axis direction. The release width W1 is, for example, about 25 μm, and the release width W2 is, for example, about 10 μm. In this way, by setting the release width W1 to be greater than the release width W2, the vibration characteristics and durability of the vibration unit 110 are improved. In addition, in order to miniaturize the resonant device 1, the release width W1 can be set to be smaller than the release width W2, or it can be set at equal intervals.

[0048] The mass-adding parts 122A to 122D each have mass-adding films 125A to 125D on their respective surfaces. Therefore, the weight per unit length (hereinafter referred to simply as "weight") of each of the mass-adding parts 122A to 122D is greater than the weight of each of the arm parts 123A to 123D. This allows for miniaturization of the vibrating part 110 and improves its vibration characteristics. Furthermore, the mass-adding films 125A to 125D not only increase the weight of the front ends of the vibrating arms 121A to 121D, but also function as frequency-adjusting films, allowing the resonant frequency of the vibrating arms 121A to 121D to be adjusted by scraping off a portion of them.

[0049] In this embodiment, the width of each of the mass attachments 122A to 122D along the X-axis is, for example, about 49 μm, which is larger than the width of each of the arms 123A to 123D along the X-axis. This allows for a further increase in the weight of each of the mass attachments 122A to 122D. For miniaturization of the resonator 10, it is preferable that the width of each of the mass attachments 122A to 122D along the X-axis is at least 1.5 times greater than the width of each of the arms 123A to 123D along the X-axis. It is sufficient that the weight of each of the mass attachments 122A to 122D is greater than the weight of each of the arms 123A to 123D; the width of each of the mass attachments 122A to 122D along the X-axis is not limited to the example of this embodiment. The width of each of the mass attachments 122A to 122D along the X-axis can be the same as, or less than, the width of each of the arms 123A to 123D along the X-axis.

[0050] When viewed from above (hereinafter referred to as "top view"), the mass attachments 122A to 122D are generally rectangular, with rounded corners, or for example, arc-shaped. Similarly, the arms 123A to 123D are generally rectangular, with arc-shaped features near the fixed end connected to the base 130 and near the connection portions connected to each of the mass attachments 122A to 122D. The shapes of the mass attachments 122A to 122D and the arms 123A to 123D are not limited to the example of this embodiment. For example, the shapes of the mass attachments 122A to 122D may also be generally trapezoidal or generally L-shaped. Furthermore, the shapes of the arms 123A to 123D may also be generally trapezoidal. The mass attachments 122A to 122D and the arm portions 123A to 123D may each be formed with a bottomed groove having an opening on either the surface side or the back side, and a hole having an opening on both the surface side and the back side. The groove and the hole may be located away from the side connecting the surface and the back side, or they may have an opening on that side side.

[0051] The base 130, when viewed from above, has a front end portion 131A, a rear end portion 131B, a left end portion 131C, and a right end portion 131D. As described above, the respective fixed ends of the vibrating arms 121A to 121D are connected to the front end portion 131A. The support arm 151A of the support arm portion 150, which will be described later, is connected to the rear end portion 131B.

[0052] The front end portion 131A, rear end portion 131B, left end portion 131C, and right end portion 131D are all parts of the outer edge of the base 130. Specifically, the front end portion 131A and the rear end portion 131B are ends extending along the X-axis direction, and are arranged opposite each other. The left end portion 131C and the right end portion 131D are ends extending along the Y-axis direction, and are arranged opposite each other. The two ends of the left end portion 131C are connected to one end of the front end portion 131A and one end of the rear end portion 131B, respectively. The two ends of the right end portion 131D are connected to the other end of the front end portion 131A and the other end of the rear end portion 131B, respectively.

[0053] Viewed from above, the base 130 is approximately rectangular with the front end 131A and rear end 131B as its long sides and the left end 131C and right end 131D as its short sides. The base 130 is formed approximately symmetrical with respect to an imaginary plane defined by the centerline CL1 along the perpendicular bisectors of the front end 131A and rear end 131B, i.e., the X-axis direction. That is, it can be said that the base 130 is formed approximately linearly symmetrical about the centerline CL1. Furthermore, the shape of the base 130 is not limited to… Figure 3 The rectangular shape shown could also be other shapes that are approximately symmetrical about the center line CL1. For example, the shape of the base 130 could also be a trapezoidal shape in which one of the front end 131A and the rear end 131B is longer than the other. In addition, at least one of the front end 131A, the rear end 131B, the left end 131C, and the right end 131D could be bent or folded.

[0054] Furthermore, the imaginary plane corresponds to the plane of symmetry of the entire vibrating section 110, and the center line CL1 corresponds to the center line of the entire vibrating section 110 in the X-axis direction. Therefore, the center line CL1 is also a line passing through the center of the vibrating arms 121A to 121D in the X-axis direction, located between the vibrating arms 121B and 121C. Specifically, each of the adjacent vibrating arms 121A and 121B is formed to be symmetrical with respect to the center line CL1 and the adjacent vibrating arms 121D and 121C.

[0055] In the base 130, the longest distance in the Y-axis direction between the front end portion 131A and the rear end portion 131B, i.e., the base length, is for example approximately 20 μm. Additionally, the longest distance in the X-axis direction between the left end portion 131C and the right end portion 131D, i.e., the base width, is for example approximately 180 μm. Furthermore, in... Figure 3 In the example shown, the base length is equivalent to the length of the left end 131C or the right end 131D, and the base width is equivalent to the length of the front end 131A or the rear end 131B.

[0056] The retaining part 140 is configured to retain the vibrating part 110. More specifically, the retaining part 140 is configured such that the vibrating arms 121A to 121D can vibrate. Specifically, the retaining part 140 is formed symmetrically with respect to an imaginary plane defined along the center line CL1. The retaining part 140 has a rectangular frame shape when viewed from above, and is arranged to surround the outer side of the vibrating part 110 along the XY plane. In this way, the retaining part 140 has a frame shape when viewed from above, thereby making it easy to realize the retaining part 140 surrounding the vibrating part 110.

[0057] Furthermore, the retaining part 140 need only be disposed around at least a portion of the vibrating part 110, and is not limited to a frame shape. For example, the retaining part 140 need only be disposed around the vibrating part 110 to a degree that it can retain the vibrating part 110 and engage with the upper cover 30 and the lower cover 20.

[0058] In this embodiment, the holding part 140 includes integrally formed frame bodies 141A to 141D. Frame body 141A is as follows: Figure 3 As shown, the frame 141B is positioned opposite the open ends of the vibrating arms 121A-121D, with its long side parallel to the X-axis. The frame 141B is opposite the rear end 131B of the base 130, with its long side parallel to the X-axis. The frame 141C is opposite the left end 131C of the base 130 and the vibrating arm 121A, with its long side parallel to the Y-axis, and its two ends are connected to one end of the frames 141A and 141B respectively. The frame 141D is opposite the right end 131D of the base 130 and the vibrating arm 121D, with its long side parallel to the Y-axis, and its two ends are connected to the other ends of the frames 141A and 141B respectively. The frames 141A and 141B, sandwiching the vibrating part 110, are positioned opposite each other in the Y-axis direction. The frames 141C and 141D, sandwiching the vibrating part 110, are positioned opposite each other in the X-axis direction.

[0059] The support arm portion 150 is disposed inside the retaining portion 140 and connects the base portion 130 and the retaining portion 140. The support arm portion 150 is not symmetrical about the center line CL1, i.e., asymmetrical. Specifically, the support arm portion 150, when viewed from above, includes one support arm 151A. The support arm 151A includes a rear support arm 152A and a side support arm 153A.

[0060] The support arm 153A extends parallel to the vibrating arm 121D between the vibrating arm 121D and the retaining part 140. Specifically, the support arm 153A extends from one end (the right end or the end on the side of the frame 141D) of the support rear arm 152A toward the frame 141A in the Y-axis direction and bends in the X-axis direction to connect with the frame 141D. That is, one end of the support arm 151A is connected to the retaining part 140.

[0061] The rear support arm 152A extends from the support side arm 153A between the rear end portion 131B of the base 130 and the retaining portion 140. Specifically, the rear support arm 152A extends towards the frame 141C in the Y-axis direction from one end (the lower end or the end on the frame 141B side) of the support side arm 153A. Furthermore, the rear support arm 152A bends in the Y-axis direction at the center of the base 130 in the X-axis direction, extends along the centerline CL1 from there, and connects to the rear end portion 131B of the base 130. That is, the other end of the support arm 151A is connected to the rear end portion 131B of the base 130.

[0062] A protrusion 50 protrudes from the recess 21 of the lower cover 20 within the vibration space. Viewed from above, the protrusion 50 is positioned between arm portion 123B of vibrating arm 121B and arm portion 123C of vibrating arm 121C. The protrusion 50 extends parallel to the arms 123B and 123C along the Y-axis, forming a prism shape. The length of the protrusion 50 in the Y-axis direction is approximately 240 μm, and its length in the X-axis direction is approximately 15 μm. Furthermore, the number of protrusions 50 is not limited to one; there can be two or more. Thus, by positioning the protrusion 50 between vibrating arms 121B and 121C and protruding from the bottom plate 22 of the recess 21, the rigidity of the lower cover 20 can be improved, suppressing the deflection of the resonator 10 formed on the lower cover 20 and the warping of the lower cover 20.

[0063] Next, refer to Figure 4 and Figure 5 The stacked structure and operation of the resonant device according to the first embodiment are described. Figure 4 It is a brief representation Figure 1 A cross-sectional view along the X-axis of the stacked structure of the resonant device 1 shown. Figure 5 It is a conceptual representation Figure 1 A cross-sectional view along the Y-axis of the stacked structure of the resonant device 1 shown.

[0064] like Figure 4 and Figure 5As shown, for the resonant device 1, the holding portion 140 of the resonator 10 is joined to the side wall 23 of the lower cover 20, and then the holding portion 140 of the resonator 10 and the side wall 33 of the upper cover 30 are joined together. In this way, the resonator 10 is held between the lower cover 20 and the upper cover 30, and the vibration space for the vibration of the resonator 110 is formed by the lower cover 20, the upper cover 30 and the holding portion 140 of the resonator 10.

[0065] The resonator 10's vibrating part 110, holding part 140, and support arm part 150 are integrally formed using the same process. In the resonator 10, a metal film E1 is stacked on a Si substrate F2, which is an example of a substrate. Furthermore, a piezoelectric film F3 is stacked on the metal film E1 to cover it, and a metal film E2 is further stacked on the piezoelectric film F3. A protective film F5 is stacked on the metal film E2 to cover it. In the mass-added parts 122A to 122D, the aforementioned mass-added films 125A to 125D are further stacked on the protective film F5, respectively. The shapes of the vibrating part 110, holding part 140, and support arm part 150 are formed by, for example, removing the laminate composed of the Si substrate F2, metal film E1, piezoelectric film F3, metal film E2, and protective film F5 by dry etching irradiation with an argon (Ar) ion beam, and then patterning the resulting material.

[0066] In this embodiment, an example is shown where the resonator 10 includes a metal film E1, but it is not limited thereto. For example, in the resonator 10, the Si substrate F2 is a degenerate silicon substrate that has low resistance, so that the Si substrate F2 itself can also serve as the metal film E1, or the metal film E1 can be omitted.

[0067] The Si substrate F2 is formed, for example, from a degenerate n-type silicon (Si) semiconductor with a thickness of about 6 μm, and may include phosphorus (P), arsenic (As), antimony (Sb), etc., as n-type dopants. Furthermore, the resistivity of the degenerate silicon (Si) used in the Si substrate F2 is, for example, less than 1.6 mΩ·cm, more preferably less than 1.2 mΩ·cm. Moreover, a silicon oxide layer F21, such as SiO2, is formed on the lower surface of the Si substrate F2 as an example of a temperature characteristic correction layer. This improves the temperature characteristics.

[0068] In this embodiment, the silicon oxide layer F21 refers to a layer that has the function of reducing the temperature coefficient of the frequency in the vibration section 110 when the temperature correction layer is formed on the Si substrate F2, i.e., the rate of change per unit temperature, at least near room temperature, compared to the case where the silicon oxide layer F21 is not formed on the Si substrate F2. By having the silicon oxide layer F21 in the vibration section 110, for example, the accompanying temperature change can be reduced in the resonant frequency of the stacked structure formed by the Si substrate F2, metal films E1 and E2, piezoelectric film F3, and silicon oxide layer F21. The silicon oxide layer may be formed on the upper surface of the Si substrate F2, or it may be formed on both the upper and lower surfaces of the Si substrate F2.

[0069] The silicon oxide layer F21 of the preferred mass addition portions 122A to 122D is formed with a uniform thickness. Furthermore, uniform thickness means that the deviation of the thickness of the silicon oxide layer F21 is within ±20% of the average thickness.

[0070] Metal films E1 and E2 each include excitation electrodes for excitation arms 121A to 121D and lead-out electrodes for electrically connecting the excitation electrodes to an external power source. The portions of metal films E1 and E2 that function as excitation electrodes are piezoelectric films F3 sandwiched between the arm portions 123A to 123D of the excitation arms 121A to 121D and facing each other. The portions of metal films E1 and E2 that function as lead-out electrodes are, for example, led out from the base 130 to the holding portion 140 via the support arm portion 150. Metal film E1 is electrically continuous throughout the resonator 10. Metal film E2 is electrically isolated in the portions formed in the excitation arms 121A and 121D and in the portions formed in the excitation arms 121B and 121C.

[0071] The thicknesses of the metal films E1 and E2 are, for example, approximately 0.1 μm and 0.2 μm or less. After deposition, the metal films E1 and E2 are patterned into excitation electrodes, lead-out electrodes, etc., by etching or other removal processes. The metal films E1 and E2 are formed, for example, from a metal material with a body-centered cubic crystal structure. Specifically, the metal films E1 and E2 are formed using Mo (molybdenum), tungsten (W), etc. In this way, the metal films E1 and E2 are mainly composed of metals with a body-centered cubic crystal structure, thereby making it easy to realize metal films E1 and E2 suitable for the lower electrode and upper electrode of the resonator 10.

[0072] The piezoelectric film F3 is a thin film formed by a piezoelectric body that converts electrical energy and mechanical energy into each other. Based on the electric field formed by the metal films E1 and E2 on the piezoelectric film F3, the piezoelectric film F3 expands and contracts along the Y-axis in the in-plane direction of the XY plane. Through the expansion and contraction of the piezoelectric film F3, the vibrating arms 121A to 121D are displaced with their open ends toward the base plate 22 of the lower cover 20 and the base plate 32 of the upper cover 30, respectively. As a result, the resonator 10 vibrates in an out-of-plane bending vibration mode.

[0073] The thickness of the piezoelectric film F3 is, for example, about 1 μm, but it can also be about 0.2 μm to 2 μm. The piezoelectric film F3 is formed from a material with a wurtzite hexagonal crystal structure, and can be primarily composed of nitrides or oxides such as aluminum nitride (AlN), scandium aluminum nitride (ScAlN), zinc oxide (ZnO), gallium nitride (GaN), and indium nitride (InN). Furthermore, scandium aluminum nitride is formed by replacing a portion of the aluminum in aluminum nitride with scandium, or it can be replaced by magnesium (Mg) and niobium (Nb), or magnesium (Mg) and zirconium (Zr). Thus, the piezoelectric film F3, with a piezoelectric material having a wurtzite hexagonal crystal structure as its main component, can be easily realized as a piezoelectric film F3 suitable for the resonator 10.

[0074] The protective film F5 protects the metal film E2 from oxidation. Furthermore, as long as the protective film F5 is disposed on the side of the upper cover 30, it need not be exposed relative to the bottom plate 32 of the upper cover 30. For example, a parasitic capacitance reducing film that reduces the capacitance of the wiring formed on the resonator 10 can be formed to cover the protective film F5. The protective film F5 can be formed of insulating films such as silicon nitride (SiN), silicon oxide (SiO2), aluminum oxide (Al2O3), and tantalum pentoxide (Ta2O5), in addition to piezoelectric films such as aluminum nitride (AlN), scandium aluminum nitride (ScAlN), zinc oxide (ZnO), gallium nitride (GaN), and indium nitride (InN). The thickness of the protective film F5 is formed to a length less than half the thickness of the piezoelectric film F3; in this embodiment, it is, for example, about 0.2 μm. More preferably, the thickness of the protective film F5 is about one-quarter the thickness of the piezoelectric film F3. Furthermore, when the protective film F5 is formed of a piezoelectric material such as aluminum nitride (AlN), it is preferable to use a piezoelectric material having the same orientation as the piezoelectric film F3.

[0075] The protective film F5 of the preferred mass additions 122A to 122D is formed with a uniform thickness. Furthermore, uniform thickness means that the thickness deviation of the protective film F5 is within ±20% of the average thickness.

[0076] The mass-adding films 125A to 125D constitute the surface of the upper cover 30 side of each of the mass-adding parts 122A to 122D, and correspond to the frequency adjustment films of each of the vibrating arms 121A to 121D. The frequency of the resonator 10 is adjusted by fine-tuning a portion of each of the mass-adding films 125A to 125D. From the perspective of frequency adjustment efficiency, it is preferable that the mass-adding films 125A to 125D are formed of a material whose etching mass reduction rate is faster than that of the protective film F5. The mass reduction rate is expressed as the product of the etching rate and the density. The etching rate is the thickness removed per unit time. If the relationship between the mass reduction rates of the protective film F5 and the mass-adding films 125A to 125D is as described above, then the magnitude relationship of the etching rates is arbitrary. Furthermore, from the viewpoint of effectively increasing the weight of the mass-adding parts 122A to 122D, it is preferable that the mass-adding films 125A to 125D are formed of a material with a higher specific gravity. For these reasons, the mass-added films 125A to 125D are formed of metallic materials such as molybdenum (Mo), tungsten (W), gold (Au), platinum (Pt), nickel (Ni), aluminum (Al), and titanium (Ti).

[0077] A portion of the upper surface of each of the mass-added films 125A to 125D is removed during the frequency adjustment process via a fine-tuning process. This fine-tuning of the mass-added films 125A to 125D can be performed, for example, by dry etching with an argon (Ar) ion beam. While the ion beam provides wide-area irradiation and excellent processing efficiency, it can potentially charge the mass-added films 125A to 125D. To prevent changes in the vibration trajectory of the vibrating arms 121A to 121D due to the Coulomb interactions caused by the charging of the mass-added films 125A to 125D, and to prevent deterioration of the vibration characteristics of the resonator 10, it is preferable that the mass-added films 125A to 125D be grounded.

[0078] Lead wires C1, C2, and C3 are formed on the protective film F5 of the holding part 140. Lead wire C1 is electrically connected to the metal film E1 through a through hole formed in the piezoelectric film F3 and the protective film F5. Lead wire C2 is electrically connected to the portion of the metal film E2 formed in the vibrating arms 121A and 121D through a through hole formed in the protective film F5. Lead wire C3 is electrically connected to the portion of the metal film E2 formed in the vibrating arms 121B and 121C through a through hole formed in the protective film F5. Lead wires C1 to C3 are formed of metallic materials such as aluminum (Al), germanium (Ge), gold (Au), and tin (Sn).

[0079] In this embodiment, Figure 4The example shown depicts arms 123A-123D, leads C2 and C3, and through electrodes V2 and V3 located on the same plane, but they are not necessarily located on the same plane. For example, through electrodes V2 and V3 may also be formed at a position in the Y-axis direction away from the cross-section of arms 123A-123D that is parallel to the ZX plane defined by the Z-axis and X-axis and cuts off from it.

[0080] Similarly, in this embodiment, in Figure 5 The example shown is an example where the mass attachment 122A, arm 123A, leads C1, C2, through electrodes V1, V2, etc. are located on the same plane cross section, but they are not necessarily located on the same plane cross section.

[0081] The bottom plate 22 and sidewall 23 of the lower cover 20 are integrally formed from a Si substrate P10. The Si substrate P10 is formed from undegenerate silicon and has a resistivity of, for example, 10 Ω·cm or higher. The Si substrate P10 is exposed inside the recess 21 of the lower cover 20. A silicon oxide layer F21 is formed on the upper surface of the protrusion 50. However, from the viewpoint of suppressing the charging of the protrusion 50, the Si substrate P10, which has a lower resistivity than the silicon oxide layer F21, can be exposed on the upper surface of the protrusion 50, and a conductive layer can also be formed therein.

[0082] The thickness of the lower cover 20 in the Z-axis direction is specified to be about 150 μm, and similarly, the depth of the recess 21 is specified to be about 50 μm.

[0083] The bottom plate 32 and sidewall 33 of the top cover 30 are integrally formed from a Si substrate Q10. Preferably, the surface, back surface, and inner surface of the through hole of the top cover 30 are covered with a silicon oxide film Q11. The silicon oxide film Q11 is formed on the surface of the Si substrate Q10, for example, by oxidation of the Si substrate Q10 or chemical vapor deposition (CVD). The Si substrate Q10 is exposed inside the recess 31 of the top cover 30. In addition, a gas-absorbing layer may be formed on the side of the recess 31 of the top cover 30 opposite to the resonator 10. The gas-absorbing layer is formed, for example, from titanium (Ti), and absorbs the exhaust gas released from the joint 40, etc., described later, to suppress the decrease of the vacuum level of the vibration space. Furthermore, the air-absorbing layer can be formed on the side of the recess 21 of the lower cover 20 opposite to the resonator 10, or it can be formed on the side of the recess 21 of the lower cover 20 and the recess 31 of the upper cover 30 opposite to the resonator 10.

[0084] The thickness of the top cover 30 in the Z-axis direction is specified to be about 150 μm, and similarly, the depth of the recess 31 is specified to be about 50 μm.

[0085] Terminals T1, T2, and T3 are formed on the upper surface of the cover 30 (the surface opposite to the resonator 10). Terminal T1 is a mounting terminal for grounding the metal film E1. Terminal T2 is a mounting terminal for electrically connecting the metal film E2 of the vibrating arms 121A and 121D to an external power supply. Terminal T3 is a mounting terminal for electrically connecting the metal film E2 of the vibrating arms 121B and 121C to an external power supply. Terminals T1 to T3 are formed, for example, by plating nickel (Ni), gold (Au), silver (Ag), or copper (Cu) onto a metallization layer (base layer) such as chromium (Cr), tungsten (W), or nickel (Ni). Furthermore, for the purpose of adjusting parasitic capacitance and balancing mechanical strength, dummy terminals electrically insulated from the resonator 10 may also be formed on the upper surface of the cover 30.

[0086] Through electrodes V1, V2, and V3 are formed inside the sidewall 33 of the upper cover 30. Through electrode V1 electrically connects terminal T1 and lead C1, through electrode V2 electrically connects terminal T2 and lead C2, and through electrode V3 electrically connects terminal T3 and lead C3. Through electrodes V1 to V3 are formed by filling conductive material through through holes in the sidewall 33 of the upper cover 30 in the Z-axis direction. The conductive material used is, for example, polysilicon (Poly-Si), copper (Cu), or gold (Au).

[0087] A joining portion 40 is formed between the sidewall 33 of the upper cover 30 and the retaining portion 140, through which the upper cover 30 and the resonator 10 are joined. The joining portion 40 is formed in a closed loop surrounding the vibrating portion 110 in the XY plane, so as to hermetically seal the vibration space of the resonator 10 under vacuum. The joining portion 40 is formed, for example, from a metal film formed by stacking and eutectic bonding an aluminum (Al) film, a germanium (Ge) film, and an aluminum (Al) film in this order. In addition, the joining portion 40 may also be formed from a combination of films appropriately selected from gold (Au), tin (Sn), copper (Cu), titanium (Ti), silicon (Si), etc. In addition, in order to improve the tightness, the joining portion 40 may also contain metal compounds such as titanium nitride (TiN) and tantalum nitride (TaN) between the films.

[0088] In this embodiment, terminal T1 is grounded, and alternating voltages with opposite phases are applied to terminals T2 and T3. Therefore, the phases of the electric fields of the piezoelectric films F3 formed on vibrating arms 121A and 121D and the piezoelectric films F3 formed on vibrating arms 121B and 121C become opposite phases. Consequently, the outer vibrating arms 121A and 121D and the inner vibrating arms 121B and 121C are displaced in opposite directions.

[0089] For example, such as Figure 4As shown, when the mass attachments 122A, 122D and arms 123A, 123D of each of the vibrating arms 121A and 121D move toward the inner surface of the upper cover 30, the mass attachments 122B, 122C and arms 123B, 123C of each of the vibrating arms 121B and 121C move toward the inner surface of the lower cover 20. Although the illustration is omitted, conversely, when the mass attachments 122A, 122D and arms 123A, 123D of each of the vibrating arms 121A and 121D move toward the inner surface of the lower cover 20, the mass attachments 122B, 122C and arms 123B, 123C of each of the vibrating arms 121B and 121C move toward the inner surface of the upper cover 30. Thus, at least two of the four vibrating arms 121A to 121D bend outwards at different phases.

[0090] Thus, vibrating arms 121A and 121B vibrate in opposite vertical directions around a central axis r1 extending along the Y-axis between adjacent vibrating arms 121A and 121B. Similarly, vibrating arms 121C and 121D vibrate in opposite vertical directions around a central axis r2 extending along the Y-axis between adjacent vibrating arms 121C and 121D. This generates torsional moments in opposite directions along the central axes r1 and r2, resulting in bending vibration in the vibrating section 110. The maximum amplitude of vibrating arms 121A to 121D is approximately 50 μm, and the amplitude during normal operation is approximately 10 μm.

[0091] Next, refer to Figure 6 as well as Figure 7 And the displacement based on the vibration of the vibrating part is explained. Figure 6 It is a schematic representation based on Figure 3 A top view of the displacement distribution of the vibration of the vibrating part 110 shown. Figure 7 It is a schematic representation based on Figure 3 A three-dimensional view of the displacement distribution of the vibration of the vibrating part 110 is shown. Furthermore, in Figure 6 as well as Figure 7 In the vibrating section 110 shown, the darker colored areas represent larger displacements, and the lighter colored areas represent smaller displacements.

[0092] like Figure 6 as well as Figure 7As shown, the vibrating part 110 vibrates in an out-of-plane bending vibration mode, thus increasing the displacement of the vibrating arms 121A to 121D. Along with the displacement of the vibrating arms 121A to 121D, the base 130, held in the holding part 140 by the support arm 150, also flexes and displaces. In this embodiment, one support arm 151A connects the holding part 140 and the base 130, and is asymmetrical about the centerline CL1 when viewed from above. Therefore, compared to the conventional method, the flexure of the base 130 is greater, and its displacement, more specifically, the displacement of the left end 131C and the right end 131D of the base 130, is also greater.

[0093] Here, refer to Figure 8 The displacement of the base based on the vibration of the vibrating part is explained. Figure 8 It means based on Figure 3 A graph showing the displacement of the base 130 of the vibrating part 110. Figure 8 In the diagram, the horizontal axis is the distance from the left end 131C of the base 130, i.e., when it is set to zero, and the vertical axis represents the relative value of the displacement. Furthermore, in... Figure 8 In the diagram, solid lines represent the displacement in the resonator 10 of this embodiment, while dashed lines represent the displacement in a conventional resonator for comparison. In a conventional resonator, the only difference is that the two support arms are formed symmetrically or approximately symmetrically about the centerline of the X-axis of the vibrating part; otherwise, the structure is the same as that of the resonator 10.

[0094] like Figure 8 As shown by the dashed line, in existing resonators, the displacement of the base is smallest near the two side ends of the base and largest near the center of the base.

[0095] In contrast, such as Figure 8 As shown by the solid line, in the resonator 10 of this embodiment, the displacement of the base 130 is smallest near the center of the base 130 and largest at both ends of the base 130, namely the left end 131C and the right end 131D. Furthermore, the displacements of the left end 131C and the right end 131D are significantly larger in absolute terms compared to the displacement near the center of the base in a conventional resonator. Therefore, it can be concluded that the displacement of the base 130 in the resonator 10 of this embodiment is larger than that in a conventional resonator.

[0096] Thus, when viewed from above, the support arm 151A is asymmetrical about the centerline CL1 of the long side of the vibrating section 110. Compared to the conventional method where it is symmetrical or approximately symmetrical about the centerline of the long side of the vibrating section, the deflection of the base 130 is greater. As a result, the rate of change of the resonant frequency per unit power, which is an indicator of DLD (Discretionary Limiting Effect), can be changed in the negative direction. Therefore, by reducing the rate of change of the resonant frequency per unit power, DLD can be further improved.

[0097] In this embodiment, Figure 3 The resonator 10 shown illustrates an example where the support arm 151A is connected to the center of the rear end portion 131B of the base 130, but this is not a limitation. The support arm 151A may also be connected to other positions of the rear end portion 131B of the base 130, provided that it is asymmetrical about the centerline CL1 when viewed from above.

[0098] Next, refer to Figure 9 as well as Figure 10 Furthermore, a modified example of the harmonic oscillator in the first embodiment will be described. Figure 9 This is a top view that briefly shows the construction of the harmonic oscillator 10 in the first variation of the first embodiment. Figure 10 This is a top view that briefly shows the construction of the harmonic oscillator 10 in the second variation of the first embodiment.

[0099] like Figure 9 As shown, in the resonator 10 of the first modified example, the support arm 151A is connected at the rear end 131B of the base 130 at a position off-center from the center line CL1. Specifically, the other end of the support arm 151A is connected at the rear end 131B of the base 130 to the side about the center line CL1 (the positive X-axis direction side or the right end 131D side).

[0100] In addition, such as Figure 10 As shown, in the resonator 10 of the second modification, the support arm 151A is connected at the rear end 131B of the base 130 at a position offset from the center line CL1. More specifically, the support arm 151A extends about the center line CL1 from one side (the positive X-axis side or the right end 131D side) to the other side (the negative X-axis side or the left end 131C side). Moreover, the other end of the support arm 151A is connected at the rear end 131B of the base 130 to the other side (the negative X-axis side or the left end 131C side) about the center line CL1.

[0101] Here, refer to Figure 11 The displacement of the base based on the vibration of the vibrating part is explained. Figure 11 It means based on Figure 9 and Figure 10 A graph showing the displacement of the base 130 of the vibrating part 110. Figure 11 In the diagram, the horizontal axis is the distance from the left end 131C of the base 130, i.e., when it is set to zero, while the vertical axis represents the relative value of the displacement. Additionally, Figure 11The lines in the diagram represent the displacement of the base 130 when the center line CL1 passes through the rear end 131B of the base 130, with one side (right side) of the center line CL1 set to positive and the other side (left side) of the center line CL1 set to negative. The displacement of the base 130 is measured when the other end of the support arm 151A is connected to the rear end 131B of the base 130 at positions of -50μm, -30μm, 30μm, and 50μm, respectively. Furthermore, in... Figure 11 In China, for those based on Figure 3 The displacement of the base 130 of the vibration of the vibration part 110 shown is represented by a line at the rear end 131B of the base 130, at the position where the center line CL1 passes, i.e., at a position of 0 μm, connecting the other end of the support arm 151A.

[0102] like Figure 11 As shown, for all connection positions, the absolute value of the displacement of the base 130 is larger than that of the base of the existing resonator. In addition, when the other end of the support arm 151A is connected to the rear end 131B of the base 130 in a negative position, that is, on the other side of the center line CL1, it can be seen that the displacement of the base 130 tends to increase.

[0103] Next, refer to Figure 12 as well as Figure 13 The connection position of the support arm on the base and its relationship with the DLD are explained. Figure 12 It means Figure 3 , Figure 9 as well as Figure 10 A graph showing the relationship between power and frequency variation rate at each connection point of the support arm 151A on the base 130. Figure 13 It means Figure 3 , Figure 9 as well as Figure 10 A graph showing the relationship between the connection position of the support arm 151A on the base 130 and the rate of change of frequency per unit power. Figure 12 In the diagram, the horizontal axis represents the power applied to the vibrating arms 121A to 121D, and the vertical axis represents the rate of change of the resonant frequency (f) (df / f). Additionally, Figure 12 The lines in the diagram are obtained by dividing the distance to the connection point of the support arm 151A by half the width of the base by the following conditions: the position where the center line CL1 passes through the rear end 131B of the base 130 is set to zero; one side (right side) of the center line CL1 is set to positive; and the other side (left side) of the center line CL1 is set to negative. The values ​​obtained are -0.58, -0.35, 0, 0.35, and 0.58, respectively. Figure 13In the diagram, the horizontal axis is the distance to the connection point of the support arm 151A divided by half the width of the base, with the position where the center line CL1 of the rear end 131B of the base 130 passes through zero, one side (right side) of the center line CL1 set to positive, and the other side (left side) of the center line CL1 set to negative. The vertical axis represents the rate of change of frequency (df / f) of the resonant frequency (f) per unit power (0.2 μW), which is an indicator of the DLD.

[0104] like Figure 12 As shown, it can be seen that the frequency change rate changes in the negative direction for all connection positions. In addition, when the other end of the support arm 151A is connected to the rear end 131B of the base 130 in a negative position, that is, on the other side of the center line CL1, it can be seen that the frequency change rate tends to tilt more in the negative direction.

[0105] Moreover, such as Figure 13 As shown, the frequency change rate per unit power is negative for all connection positions, but its absolute value increases when the other end of the support arm 151A is connected to the position on the other side of the center line CL1.

[0106] Thus, the other end of the support arm 151A is connected at a position off-center from the center line CL1 at the rear end 131B of the base 130, thereby increasing the deflection of the base 130.

[0107] In addition, the support arm 151A extends from one side to the other about the center line CL1, and the other end of the support arm 151A is connected to the other side of the rear end 131B of the base 130, thereby further increasing the deflection of the base 130.

[0108] Furthermore, the other end of the support arm 151A is not limited to being connected to the rear end 131B of the base 130. As long as the support arm 151A is asymmetrical about the centerline CL1 when viewed from above, the other end of the support arm 151A may also be connected to the side of the base 130, for example.

[0109] Next, refer to Figure 14 Furthermore, another variation of the harmonic oscillator in the first embodiment will be described. Figure 14 This is a top view that briefly shows the structure of the harmonic oscillator 10 in the third variation of the first embodiment.

[0110] like Figure 14As shown, in the third modified example of the resonator 10, the support arm 151A is connected to the left end 131C of the base 130. More specifically, the support arm 151A extends about the center line CL1 from one side (the positive X-axis side or the right end 131D side) to the other side (the negative X-axis side or the left end 131C side). Moreover, it bends towards the positive Y-axis side between the frame 141C and the vibrating arm 121A, and further bends towards the positive X-axis side, with the other end of the support arm 151A connected to the left end 131C of the base 130.

[0111] Thus, when viewed from above, the support arm 151A extends from one side to the other with respect to the center line CL1 along the long side of the vibrating section 110. The other end of the support arm 151A connects to the left end 131C on the other side of the base 130. Compared to the conventional configuration where the base 130 is symmetrical or approximately symmetrical with respect to the center line along the long side of the vibrating section, the deflection of the base 130 is increased. As a result, the rate of change of the resonant frequency per unit power can be changed in the negative direction. Therefore, the rate of change of the resonant frequency per unit power can be reduced, further improving the DLD (Dissonance Lamp).

[0112] Next, refer to Figure 15 The dimensions of the vibrating part when viewed from above are also explained. Figure 15 It is used for explanation Figure 3 A top view showing the dimensions of the vibrating part 110.

[0113] like Figure 15 As shown, in the resonator 10 of this embodiment, the width WG of each of the mass additions 122A to 122D along the X-axis is, for example, 49 μm. Furthermore, the width WA of each of the vibrating arms 121A to 121D along the X-axis is, for example, 26 μm, and the length LA of each of the vibrating arms 121A to 121D along the Y-axis is, for example, 415 μm.

[0114] Furthermore, in the base 130, the distance in the longitudinal direction from the front end 131A to the rear end 131B, that is, the length of the base width WB, is, for example, 18 μm. Conversely, the distance in the width direction from the left end 131C to the right end 131D, that is, the length of the base length LB, is, for example, 20 μm.

[0115] Here, the inventors of this invention have discovered that when the ratio of the length of the base length LB to the length of the base width WB is less than a predetermined multiple, the rate of change of the resonant frequency per unit power can be reduced. More specifically, it has been found that it is preferable for the length of the base length LB to be less than 0.3 times the length of the base width WB. This effectively reduces the rate of change of the resonant frequency per unit power.

[0116] Specifically, in the miniaturized resonator 10, the length of the base length LB is 90 μm or less, and the length of the base width WB is 300 μm or less. Thus, even in the miniaturized and size-limited resonator 10, the rate of change of the resonant frequency per unit power can be effectively reduced.

[0117] In addition, the length of the support arm 151A along the X-axis direction, the support arm width WS, is, for example, 25 μm, and the length of the support arm 151A along the Y-axis direction, the support arm length LS, is, for example, 225 μm.

[0118] In this embodiment, the resonator 10 is used in an example where the vibrating section 110 includes four vibrating arms 121A to 121D, but it is not limited to this. The vibrating section 110 may also include three or more vibrating arms, for example. In this case, at least two vibrating arms bend out of plane with different phases.

[0119] [Second Implementation]

[0120] Next, refer to Figures 16-21 The resonator and resonant device according to the second embodiment of the present invention will be described. Furthermore, in the following embodiments, structures that are the same as or similar to those in the first embodiment will be labeled with the same or similar reference numerals, and differences from the first embodiment will be described. Additionally, the same effects resulting from the same structures will not be mentioned sequentially.

[0121] First, refer to Figure 16 A brief description of the structure of the harmonic oscillator according to the second embodiment is provided. Figure 16 This is a top view that briefly illustrates the construction of the resonator 210 in the second embodiment. Furthermore, Figure 16 It is the same as in the first embodiment. Figure 3 The corresponding top view.

[0122] The second embodiment of the resonator 210 differs from the first embodiment of the resonator 10 in that the support arm portion 250 includes two support arms 251A and 251B.

[0123] like Figure 16 As shown, in the resonator 210, the support arm portion 250 includes support arm 251A and support arm 251B. In addition, the support arm portion 250 also includes a connecting arm 255.

[0124] Support arms 251A and 251B are configured to be asymmetrical about the centerline CL1 when viewed from above. Specifically, support arm 251A includes a rear support arm 252A and a side support arm 253A, while support arm 251B includes a rear support arm 252B.

[0125] The support arm 253A is located between the vibrating arm 121D and the retaining part 140, and extends parallel to the vibrating arm 121D. Specifically, the support arm 253A extends from one end (the right end or the end on the side of the frame 141D) of the support rear arm 252A toward the frame 141A in the Y-axis direction, and bends in the X-axis direction to connect with the frame 141D.

[0126] The rear support arm 252A extends from the support side arm 253A between the rear end portion 131B of the base 130 and the retaining portion 140. Conversely, the rear support arm 252B extends from the retaining portion 140 between the rear end portion 131B of the base 130 and the retaining portion 140. Specifically, the rear support arm 252A extends towards the frame 141C in the X-axis direction from one end (the lower end or the end on the frame 141B side) of the support side arm 253A. Conversely, one end (the left end or the end on the frame 141C side) of the rear support arm 252B is connected to the frame 141C and extends towards the frame 141D in the Y-axis direction. That is, one end of each of the support arms 251A and 251B is connected to the retaining portion 140.

[0127] Furthermore, the rear support arms 252A and 252B are connected between the rear end portion 131B of the base 130 and the retaining portion 140. Specifically, the other end (left end) of the rear support arm 252A and the other end (right end) of the rear support arm 252B are connected at the center in the X-axis direction of the rear support arm 252A and the rear support arm 252B.

[0128] The connecting arm 255 connects the other ends of the two connected support arms 251A and 251B to the rear end 131B of the base 130. The connecting arm 255 is connected to the rear end 131B of the base 130 at a location where the center line CL1 passes.

[0129] In this way, when viewed from above, one of the two support arms 251A and the other support arm 251B is asymmetrical about the center line CL1. As a result, compared with the previous method where the support arms were symmetrical or approximately symmetrical about the center line in the long side direction of the vibrating part, the deflection of the base 130 is increased. Even for a resonator 210 with two support arms 251A and 251B, the DLD can be further improved.

[0130] In this embodiment, Figure 16 The resonator 210 shown illustrates an example where support arms 251A and 251B are connected by connecting arms 255 to the center of the rear end portion 131B of the base 130, but this is not a limitation. Support arms 251A and 251B can also be connected at other locations on the rear end portion 131B of the base 130, provided they are asymmetrical about the centerline CL1 when viewed from above.

[0131] Next, refer to Figure 17 as well as Figure 18 A modified example of the harmonic oscillator in the second embodiment will be described. Figure 17 This is a top view that briefly shows the construction of the harmonic oscillator 210 in the first variation of the second embodiment. Figure 18 This is a top view that briefly shows the construction of the harmonic oscillator 210 in the second variation of the second embodiment.

[0132] like Figure 17 As shown, in the resonator 210 of the first modified example, support arms 251A and 251B are connected at the rear end 131B of the base 130 at a position offset from the centerline CL1. Specifically, the other ends of the support arms 252A and 252B are connected on one side (the positive X-axis side or the right end 131D side) about the centerline CL1. Furthermore, the connecting arm 255, which connects the other ends of the two support arms 251A and 251B to the rear end 131B of the base 130, is connected on one side of the rear end 131B of the base 130 about the centerline CL1.

[0133] In addition, such as Figure 18 As shown, in the resonator 210 of the second modification, support arms 251A and 251B are connected at the rear end 131B of the base 130 at a position offset from the centerline CL1. Specifically, the other ends of the support arms 252A and 252B are connected on the other side (the negative X-axis side or the left end 131C side) about the centerline CL1. Furthermore, the connecting arm 255, which connects the other ends of the two support arms 251A and 251B to the rear end 131B of the base 130, is connected on the other side about the centerline CL1 at the rear end 131B of the base 130.

[0134] Next, refer to Figures 19-21 Another variation of the harmonic oscillator in the second embodiment will be described. Figure 19 This is a top view that briefly illustrates the construction of the harmonic oscillator 210 in the third variation of the second embodiment. Figure 20 This is a top view that briefly shows the construction of the harmonic oscillator 210 in the fourth variation of the second embodiment. Figure 21 This is a top view that briefly shows the construction of the harmonic oscillator 210 in the fifth variation of the second embodiment.

[0135] like Figure 19 as well as Figure 20 As shown, in the third and fourth modifications of the resonator 210, the support arm 251B, in addition to supporting the rear arm 252B, also includes a support side arm 253B.

[0136] The support arm 253B is located between the vibrating arm 121A and the retaining part 140, and extends parallel to the vibrating arm 121A. Specifically, the support arm 253B extends from one end (the left end or the end on the side of the frame 141C) of the support rear arm 252B toward the frame 141A in the Y-axis direction, and bends in the X-axis direction to connect with the frame 141C.

[0137] Furthermore, in the third and fourth modifications of the resonator 210, the support arm widths WS1 and WS2 of support arm 251A and support arm 251B are different in length.

[0138] Specifically, such as Figure 19 As shown, the length of the support arm width WS1 along the X-axis of the support arm 253A is smaller than the length of the support arm width WS2 along the X-axis of the support arm 253B (the length of the support arm width WS1 < the length of the support arm width WS2).

[0139] In addition, such as Figure 20 As shown, the length of the support arm width WS1 along the Y-axis of the rear support arm 252A and the length of the support arm width WS1 along the X-axis of the side support arm 253A are smaller than the length of the support arm width WS2 along the Y-axis of the rear support arm 252B and the length of the support arm width WS2 along the X-axis of the side support arm 253B (the length of the support arm width WS1 < the length of the support arm width WS2).

[0140] In this way, the support arm widths WS1 and WS2 of one of the two support arms 251A and 251B are different in length, which makes it easy for the two support arms 251A and 251B to be asymmetrical about the center line CL1.

[0141] On the other hand, in the fifth variation of the resonator 210, the lengths of the support arms LS1 and LS2 of the support arms 251A and 251B are different.

[0142] Specifically, such as Figure 21 As shown, the length of the support arm LS1 along the Y-axis of the support arm 253A is greater than the length of the support arm LS2 along the Y-axis of the support arm 253B (the length of the support arm LS1 is greater than the length of the support arm LS2).

[0143] In this way, the lengths of the support arms LS1 and LS2 of one support arm 251A and the other support arm 251B are different, which makes it easy for the two support arms 251A and 251B to be asymmetrical about the center line CL1.

[0144] The exemplary embodiments of the present invention have been described above. In a resonator according to one embodiment, the support arm is asymmetrical about the centerline of the long side of the vibrating part when viewed from above. As a result, compared with the conventional method where the support arm is symmetrical or substantially symmetrical about the centerline of the long side of the vibrating part, the deflection of the base is greater, and consequently, the rate of change of the resonant frequency per unit power, which is an indicator of DLD (Dissonance Damping) can be changed in the negative direction. Therefore, the rate of change of the resonant frequency per unit power can be reduced, and DLD can be further improved.

[0145] Furthermore, in the aforementioned resonator, the other end of the support arm is connected to the rear end of the base at a position off-center from the centerline. Therefore, the other end of the support arm is connected to the rear end of the base at an asymmetrical position about the centerline, thus allowing for greater deflection of the base.

[0146] Furthermore, in the aforementioned resonator, the support arm extends from one side to the other about the centerline, with the other end of the support arm connected to the other side of the rear end of the base. This allows for a further increase in the deflection of the base.

[0147] Furthermore, in the aforementioned resonator, one of the two support arms is asymmetrical about the centerline when viewed from above. Therefore, compared to conventional resonators that are symmetrical or approximately symmetrical about the centerline along the long side of the vibrating section, the base deflection is increased, further improving the DLD (Distortion of Leverage) even in resonators with two support arms.

[0148] Furthermore, in the aforementioned resonator, the lengths of the support arms of one and the other are different. This allows the two support arms to be easily made asymmetrical about the center line.

[0149] Furthermore, in the aforementioned resonator, the lengths of one of the two support arms are different from those of the other, thus making it easy for the two support arms to be asymmetrical about the center line.

[0150] Furthermore, in the aforementioned resonator, the length of the base length is 0.3 times or less than the length of the base width. Here, the inventors of this invention have discovered that when the ratio of the length of the base length to the length of the base width is a predetermined multiple or less, more specifically 0.3 times or less, the rate of change of the resonant frequency per unit power can be reduced. Therefore, the rate of change of the resonant frequency per unit power can be effectively reduced.

[0151] Furthermore, in the aforementioned resonator, the base length is 90 μm or less, and the base width is 300 μm or less. Therefore, even in a miniaturized resonator with limited dimensions, the rate of change of the resonant frequency per unit power can be effectively reduced.

[0152] Furthermore, in one embodiment of the resonator, the support arm, when viewed from above, extends from one side to the other about the centerline of the long side of the vibrating section. The other end of the support arm is connected to the left end of the base on the other side. Compared to conventional designs that are symmetrical or substantially symmetrical about the centerline of the long side of the vibrating section, the deflection of the base is increased. As a result, the rate of change of the resonant frequency per unit power can be changed in the negative direction. Therefore, the rate of change of the resonant frequency per unit power can be reduced, further improving the DLD (Dissonance-Lowering Component).

[0153] Furthermore, the resonant device according to one embodiment includes the aforementioned resonator. Therefore, a resonant device for further improvement of DLD can be realized.

[0154] Furthermore, the aforementioned resonant device also includes a lower cover and an upper cover. This allows for the easy formation of a vibration space for an out-of-plane bending vibration section.

[0155] Furthermore, the embodiments described above are for the purpose of facilitating understanding of the present invention and are not intended to limit or interpret the scope of the present invention. The present invention can be modified / improved without departing from its spirit, and its equivalents are also included within the present invention. That is, structures obtained by appropriately applying design changes to the embodiments and / or modifications by those skilled in the art, as long as they possess the features of the present invention, are also included within the scope of the present invention. For example, the elements, their configurations, materials, conditions, shapes, dimensions, etc., of the embodiments and / or modifications are not limited to the illustrated content and can be appropriately modified. In addition, the embodiments and modifications are illustrative; of course, partial substitutions or combinations of the structures shown in different embodiments and / or modifications are possible, and these structures, as long as they contain the features of the present invention, are included within the scope of the present invention.

[0156] Explanation of reference numerals in the attached figures

[0157] 1…Resonant device; 10…Resonator; 20…Lower cover; 21…Recess; 22…Base plate; 23…Side wall; 30…Upper cover; 31…Recess; 32…Base plate; 33…Side wall; 40…Joint; 50…Protrusion; 110…Vibrating part; 120…Excitation part; 121, 121A, 121B, 121C, 121D…Vibrating arm; 122A, 122B, 122C, 122D…Mass attachment; 123A, 123B, 123C, 123D…Arm; 125A, 125B, 125C, 125D…Mass attachment membrane; 130…Base; 131A…Front end; 131B…Rear end; 131C…Left end; 13 1D…Right end; 140…Holding part; 141A, 141B, 141C, 141D…Frame; 150…Support arm; 151A…Support arm; 152A…Support rear arm; 153A…Support side arm; 210…Resonator; 250…Support arm; 251A, 251B…Support arm; 252A, 252B…Support rear arm; 253A, 253B…Support side arm; 255…Connecting arm; CL1…Center line; LA…Vibration arm length; LB…Base length; LS, LS1, LS2…Support arm length; r1, r2…Center axis; WA…Vibration arm width; WB…Base width; WG…Width; WS, WS1, WS2…Support arm width.

Claims

1. A harmonic oscillator, possessing: The vibrating section includes multiple vibrating arms and a base, wherein, The plurality of vibrating arms are three or more and each has a fixed end, at least two of which are bent out of plane at different phases, and the base has one end for connecting to the fixed end of each of the plurality of vibrating arms and another end opposite to that end. The retaining part is configured to retain the vibrating part; and The support arm has one end connected to the retaining part and the other end connected to the other end of the base. The support arm is asymmetrical about the centerline of the long side of the vibrating part when viewed from above. The support arm extends from one side to the other about the center line. The other end of the support arm is connected to the other side of the other end of the base.

2. The harmonic oscillator according to claim 1, wherein, The other end of the support arm is connected to the other end of the base at a position off the center line.

3. The harmonic oscillator according to claim 1, wherein, Equipped with two of the aforementioned support arms, One of the two support arms and the other support arm are asymmetrical about the centerline when viewed from above.

4. The harmonic oscillator according to claim 2, wherein, Equipped with two of the aforementioned support arms, One of the two support arms and the other support arm are asymmetrical about the centerline when viewed from above.

5. The harmonic oscillator according to claim 3, wherein, The lengths of the support arms of one of the two support arms are different from those of the other support arm.

6. The harmonic oscillator according to claim 4, wherein, The lengths of the support arms of one of the two support arms are different from those of the other support arm.

7. The harmonic oscillator according to claim 3, wherein, The lengths of one of the two support arms are different from those of the other support arm.

8. The harmonic oscillator according to claim 4, wherein, The lengths of one of the two support arms are different from those of the other support arm.

9. The harmonic oscillator according to claim 5, wherein, The lengths of one of the two support arms are different from those of the other support arm.

10. The harmonic oscillator according to claim 6, wherein, The lengths of one of the two support arms are different from those of the other support arm.

11. The harmonic oscillator according to any one of claims 1 to 10, wherein, The length of the base in the length direction from one end of the base toward the other end is less than 0.3 times the length of the base width in the width direction orthogonal to the length direction.

12. The harmonic oscillator according to claim 11, wherein, The base length is less than 90 μm, and the base width is less than 300 μm.

13. A harmonic oscillator, possessing: The vibrating section includes multiple vibrating arms and a base, wherein, The plurality of vibrating arms consists of three or more arms, each having a fixed end, with at least two arms being bent out of plane at different phases. The base has an end for connecting to the fixed end of each of the plurality of vibrating arms, an end opposite to that end, and a side end. The retaining part is configured to retain the vibrating part; and The support arm has one end connected to the retaining part and the other end connected to the side end of the base. When viewed from above, the center line of the support arm extends from one side to the other along the long side of the vibrating part. The other end of the support arm is connected to the side end on the other side of the base.

14. A resonant device, wherein, It possesses the harmonic oscillator described in any one of claims 1 to 13.

15. The resonant device according to claim 14, wherein, It also has a cover.

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