WO2022024438A1

WO2022024438A1 - Resonator, and resonating device

Info

Publication number: WO2022024438A1
Application number: PCT/JP2021/009077
Authority: WO
Inventors: 宏中谷
Original assignee: 株式会社村田製作所
Priority date: 2020-07-29
Filing date: 2021-03-08
Publication date: 2022-02-03
Also published as: JP7449496B2; JPWO2022024438A1

Abstract

This resonator is provided with a vibrating portion, a holding portion provided in at least a portion of the perimeter of the vibrating portion, and a holding arm provided between the vibrating portion and the holding portion, wherein: the vibrating portion includes a first vibrating arm which has a fixed end and an open end, and which bends out of plane, and a second vibrating arm which has a fixed end and an open, and which bends out of a plane with a phase different from the first vibrating arm, and a base portion to which the first vibrating arm and the second vibrating arm are connected in parallel; the holding arm has one end connected to the base portion and the other end connected to the holding portion; the first vibrating arm has a first offset structure in which the position of the center of gravity of the first vibrating arm is offset toward the inside of the vibrating portion, in the parallel direction of the first vibrating arm and the second vibrating arm, from a first central axis, in the lateral direction of the first vibrating arm, of the boundary between the first vibrating arm and the base portion; and the second vibrating arm has a second offset structure in which the position of the center of gravity of the second vibrating arm is offset toward the inside of the vibrating portion, in the parallel direction of the first vibrating arm and the second vibrating arm, from a second central axis, in the lateral direction of the second vibrating arm, of the boundary between the second vibrating arm and the base portion.

Description

Resonator and resonator

The present invention relates to a resonator and a resonator.

Resonators such as piezoelectric vibrators are used as devices for realizing the timekeeping function in electronic devices. With the miniaturization of electronic devices, miniaturization of resonators is also required, and resonators manufactured using MEMS (Micro Electro Mechanical Systems) technology (hereinafter, also referred to as "MEMS oscillators") are attracting attention. ing.

For example, in Patent Document 1, two vibrating arms located inside and two vibrating arms located outside are flexed and vibrated in opposite phases to vibrate due to the flexion vibration of the vibrating arm. A resonator that cancels the rotational moment of the vibrating arm around the central axis extending in the longitudinal direction of the arm is described.

Japanese Patent No. 6525292

However, in the conventional technique, the rotational moment around the central axis extending in the longitudinal direction of the vibrating arm due to the bending vibration of the vibrating arm may not be sufficiently offset. In this case, vibration leakage from the holding portion may affect the vibration characteristics of the vibrating portion.

The present invention has been made in view of such circumstances, and is a resonator capable of stabilizing the vibration characteristics of the vibrating portion by canceling the rotational moment around the central axis extending in the longitudinal direction of the vibrating arm. And to provide a resonator.

The resonator according to one aspect of the present invention includes a vibrating portion, a holding portion provided at least a part around the vibrating portion, a holding arm provided between the vibrating portion and the holding portion, and a holding arm. The vibrating portion has a fixed end and an open end, and has a first vibrating arm that bends out-of-plane, and a fixed end and an open end, and bends out-of-plane in a phase different from that of the first vibrating arm. The holding arm includes a second vibrating arm, a front end to which the first vibrating arm and the second vibrating arm are connected in parallel, and a base having a rear end facing the front end, and the holding arm has one end. The first vibrating arm is connected to the base portion and the other end is connected to the holding portion, and the first vibrating arm is a first central axis in the lateral direction of the first vibrating arm at a boundary portion between the first vibrating arm and the base portion. The second vibrating arm has a first offset structure for offsetting the position of the center of gravity of the first vibrating arm inside the vibrating portion in the parallel direction of the first vibrating arm and the second vibrating arm. The position of the center of gravity of the second vibrating arm is offset to the inside of the vibrating portion in the parallel direction from the second central axis in the lateral direction of the second vibrating arm at the boundary portion between the second vibrating arm and the base portion. It has a two-offset structure.

According to the present invention, the vibration characteristics of the vibrating portion can be stabilized by canceling the rotational moment around the central axis extending in the longitudinal direction of the vibrating arm.

It is a perspective view schematically showing the appearance of the resonance apparatus which concerns on one Embodiment. It is an exploded perspective view which shows schematic structure of the resonance apparatus which concerns on one Embodiment. It is a top view of the resonator which concerns on one Embodiment which removed the upper substrate. It is sectional drawing along the AA'line of FIG. It is a figure for demonstrating the operation at the time of bending vibration of a vibrating part. It is a figure which shows an example of the structure of the resonator which concerns on one Embodiment. It is a figure for demonstrating the function of the resonator of the comparative example. It is a figure for demonstrating the function of the resonator which concerns on one Embodiment. It is a figure which shows the modification of the structure of the resonator which concerns on one Embodiment. It is a figure which shows the modification of the structure of the resonator which concerns on one Embodiment. It is a figure which shows the modification of the structure of the resonator which concerns on one Embodiment. It is a figure which shows the modification of the structure of the resonator which concerns on one Embodiment. It is a figure which shows the modification of the structure of the resonator which concerns on one Embodiment. It is a figure which shows the modification of the structure of the resonator which concerns on one Embodiment. It is a figure which shows the modification of the structure of the resonator which concerns on one Embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing the appearance of the resonance device 1 according to the embodiment of the present invention. Further, FIG. 2 is an exploded perspective view schematically showing the structure of the resonance device 1 according to the embodiment of the present invention.

The resonator 1 includes a resonator 10 and an upper lid 30 and a lower lid 20 provided so as to face each other with the resonator 10 interposed therebetween. That is, the resonator 1 is configured by stacking the lower lid 20, the resonator 10, and the upper lid 30 in this order.

Further, the resonator 10 is joined to the lower lid 20 and the upper lid 30, whereby the resonator 10 is sealed and the vibration space of the resonator 10 is formed. The resonator 10, the lower lid 20, and the upper lid 30 are each formed by using a Si substrate. The Si substrates of the resonator 10, the lower lid 20, and the upper lid 30 are joined to each other. The resonator 10 and the lower lid 20 may be formed by using an SOI substrate.

The resonator 10 is a MEMS resonator manufactured by using MEMS technology. In this embodiment, the resonator 10 will be described as an example of being formed by using a silicon substrate. Hereinafter, each configuration of the resonance device 1 will be described in detail.

(1. Top lid 30)
The upper lid 30 extends in a flat plate shape along the XY plane, and for example, a flat rectangular parallelepiped concave portion 31 is formed on the back surface thereof. The recess 31 is surrounded by the side wall 33 and forms a part of the vibration space, which is the space where the resonator 10 vibrates.

(2. Lower lid 20)
The lower lid 20 has a rectangular plate-shaped bottom plate 22 provided along the XY plane and a side wall 23 extending from the peripheral edge of the bottom plate 22 in the Z-axis direction (that is, the stacking direction of the lower lid 20 and the resonator 10). Have. The lower lid 20 is provided with a recess 21 formed by the surface of the bottom plate 22 and the inner surface of the side wall 23 on the surface facing the resonator 10. The recess 21 forms a part of the vibration space of the resonator 10. The vibration space is airtightly sealed by the upper lid 30 and the lower lid 20 described above, and a vacuum state is maintained. The vibration space may be filled with a gas such as an inert gas.

(3. Resonator 10)
FIG. 3 is a plan view schematically showing the structure of the resonator 10 according to the present embodiment. Each configuration of the resonator 10 according to the present embodiment will be described with reference to FIG. The resonator 10 includes a vibrating portion 120, a holding portion 140, and a holding arm 110.

(A) Vibration unit 120
The vibrating unit 120 has a rectangular contour extending along the XY plane in the Cartesian coordinate system of FIG. The vibrating portion 120 is provided inside the holding portion 140, and a space is formed between the vibrating portion 120 and the holding portion 140 at a predetermined interval. In the example of FIG. 3, the vibrating unit 120 is a tuning fork type oscillator and has a base 130 and two vibrating

arms

135A and 135B (collectively referred to as “vibrating arm 135”). In the present embodiment, each vibrating arm 135 and the base 130 are integrally formed.

The base 130 has

long sides

131a and 131b in the X-axis direction and

short sides

131c and 131d in the Y-axis direction in a plan view. The long side 131a is one side of the front end surface 131A (hereinafter, also referred to as “front end 131A”) of the base 130, and the long side 131b is the rear end surface 131B (hereinafter, “rear end 131B”) of the base 130. Also called.) It is one side of. In the base 130, the front end 131A and the rear end 131B are provided so as to face each other. The front end 131A of the base 130 is connected to the vibrating arm 135 described later, and the rear end 131B of the base 130 is connected to the holding arm 110 described later.

The vibrating arm 135 extends in the Y-axis direction and has the same size. Each of the vibrating arms 135 is provided between the base 130 and the holding portion 140 in parallel in the Y-axis direction, one end is connected to the front end 131A of the base 130 to be a fixed end, and the other end is an open end. It has become. Further, the vibrating arms 135 are provided in parallel at predetermined intervals in the X-axis direction, respectively. That is, the X-axis direction corresponds to the parallel direction in which the two vibrating

arms

135A and 135B are parallel to each other. The vibrating arm 135 has, for example, a width of about 50 μm in the X-axis direction and a length of about 465 μm in the Y-axis direction.

The open end of the vibrating arm 135 has a weight portion. Unlike the example shown in FIG. 3, the weight portion may be wider in the X-axis direction than, for example, other portions of the vibrating arm 135. Alternatively, the weight portion may have the same width in the X-axis direction as the other portion of the vibrating arm 135. Such weight portions having the same width can be formed, for example, by laminating metal layers. Since the open end of the vibrating arm 135 has a weight portion, the weight per unit length of the vibrating arm 135 is heavier on the open end side than on the fixed end side. Therefore, the amplitude of the vertical vibration of the vibrating arm 135 can be increased.

A protective film 235 is formed on the surface of the vibrating portion 120 (the surface facing the upper lid 30) so as to cover the entire surface thereof. Further,

frequency adjusting films

236A and 236B (hereinafter, the

frequency adjusting films

236A and 236B are collectively referred to as "frequency adjusting film 236") are provided on a part of the surface of the protective film 235 in the vibrating

arms

135A and 135B, respectively. It is formed. The resonance frequency of the vibrating unit 120 can be adjusted by the protective film 235 and the frequency adjusting film 236. Although the protective film 235 does not necessarily cover the entire surface of the vibrating portion 120, damage to the underlying electrode film (for example, the metal layer E2 in FIG. 4) and the piezoelectric film (for example, the piezoelectric thin film F3 in FIG. 4) in frequency adjustment is caused. It is desirable that the entire surface of the vibrating portion 120 is protected.

The frequency adjusting film 236 is formed on the protective film 235 so that the surface of the vibrating portion 120 is exposed at least in at least a part of the region where the displacement due to vibration is relatively larger than the other regions. Specifically, the frequency adjusting film 236 is formed on the tip of the vibrating arm 135, that is, the weight portion. On the other hand, the surface of the protective film 235 is exposed in other regions of the vibrating arm 135. In this embodiment, the frequency adjusting film 236 is formed up to the tip of the vibrating arm 135, and the protective film 235 is not exposed at all at the tip, but the frequency adjusting film 236 is provided so that a part of the protective film 235 is exposed. A configuration that is not formed at the tip of the vibrating arm 135 is also possible.

(B) Holding unit 140
The holding portion 140 is formed in a rectangular frame shape along the XY plane. The holding portion 140 is provided so as to surround the outside of the vibrating portion 120 along the XY plane in a plan view. The holding portion 140 may be provided at least in a part around the vibrating portion 120, and is not limited to the frame shape. For example, the holding portion 140 may be provided around the vibrating portion 120 so as to hold the vibrating portion 120 and to be joined to the upper lid 30 and the lower lid 20.

In the present embodiment, the holding portion 140 is composed of prismatic frame bodies 140a to 140d integrally formed. As shown in FIG. 3, the frame body 140a is provided so as to face the open end of the vibrating arm 135 and to be provided in the longitudinal direction parallel to the X axis. The frame body 140b is provided so as to face the rear end 131B of the base 130 and the longitudinal direction is parallel to the X axis. The frame body 140c is provided so as to face the side end (short side 131c) of the base 130 and the vibrating arm 135A, and the longitudinal direction is parallel to the Y axis. One end of the frame body 140c is connected to the frame body 140a, and the other end of the frame body 140c is connected to the frame body 140b. The frame body 140d is provided so as to face the side end (short side 131d) of the base 130 and the vibrating arm 135B, and the longitudinal direction is parallel to the Y axis. One end of the frame body 140d is connected to the frame body 140a, and the other end of the frame body 140d is connected to the frame body 140b.

(C) Holding arm 110
The holding arm 110 is provided inside the holding portion 140, and connects the rear end 131B of the base 130 and the frame body 140b. One end of the holding arm 110 is connected to the rear end 131B of the base 130, and the other end of the holding arm 110 is connected to the frame body 140b. The holding arm 110 is provided so that the longitudinal direction is parallel to the Y axis.

(4. Laminated structure)
The laminated structure of the resonator 10 will be described with reference to FIG. FIG. 4 is a schematic view schematically showing the AA'cross section of FIG. 3 and the electrical connection mode of the resonator 10.

In the resonator 10, the holding portion 140, the base 130, the vibrating arm 135, and the holding arm 110 are integrally formed by the same process. In the resonator 10, first, the metal layer E1 is laminated on the Si (silicon) substrate F2. A piezoelectric thin film F3 is laminated on the metal layer E1 so as to cover the metal layer E1, and a metal layer E2 is laminated on the surface of the piezoelectric thin film F3. A protective film 235 is laminated on the metal layer E2 so as to cover the metal layer E2. On the vibrating portion 120, a frequency adjusting film 236 is further laminated on the protective film 235.

The metal layers E1 and E2 are formed by using, for example, Mo (molybdenum), aluminum (Al), or the like having a thickness of about 0.1 to 0.2 μm. The metal layers E1 and E2 are formed into a desired shape by etching or the like. The metal layer E1 functions as a lower electrode, for example, on the vibrating portion 120. Further, the metal layer E1 functions as wiring for connecting the lower electrode to the AC power supply provided outside the resonator 10 on the holding arm 110 and the holding portion 140.

The metal layer E2 functions as an upper electrode on the vibrating portion 120. Further, the metal layer E2 functions as wiring for connecting the upper electrode to the circuit provided outside the resonator 10 on the holding arm 110 and the holding portion 140.

The piezoelectric thin film F3 is a piezoelectric thin film that converts an applied voltage into vibration, and can contain, for example, a nitride or oxide such as AlN (aluminum nitride) as a main component. Specifically, the piezoelectric thin film F3 can be formed of ScAlN (scandium nitride aluminum). ScAlN is obtained by substituting a part of aluminum in aluminum nitride with scandium.

The piezoelectric thin film F3 expands and contracts in the in-plane direction of the XY plane, that is, in the Y-axis direction, according to the electric field applied to the piezoelectric thin film F3 by the metal layers E1 and E2. Due to the expansion and contraction of the piezoelectric thin film F3, the vibrating arm 135 displaces its open end toward the inner surfaces of the lower lid 20 and the upper lid 30 and vibrates in an out-of-plane bending vibration mode.

The protective film 235 is a layer of an insulator, and is formed of a material whose mass reduction rate by etching is slower than that of the frequency adjusting film 236. For example, the protective film 235 is formed of a nitride film such as AlN or SiN or an oxide film such as Ta2O5 (tantalum pentoxide) or SiO2. The mass reduction rate is expressed by the product of the etching rate (thickness removed per unit time) and the density.

The frequency adjustment film 236 is a layer of a conductor, and is formed of a material whose mass reduction rate by etching is faster than that of the protective film 235. The frequency adjusting film 236 is formed of, for example, a metal such as molybdenum (Mo), tungsten (W), gold (Au), platinum (Pt), nickel (Ni), aluminum (Al), and titanium (Ti).

(5. Operation of resonator)
The operation of the resonator 10 will be described with reference to FIG. In the present embodiment, the phase of the electric field applied to the vibrating arm 135A and the phase of the electric field applied to the vibrating arm 135B are set to be opposite to each other. As a result, the vibrating arm 135A and the vibrating arm 135B are displaced in opposite directions. For example, when the vibrating arm 135A displaces the open end toward the inner surface of the upper lid 30, the vibrating arm 135B displaces the open end toward the inner surface of the lower lid 20.

As a result, in the resonator 10 according to the present embodiment, when vibrating in opposite phase, that is, the vibrating arm 135A and the vibrating arm 135B shown in FIG. 4 vibrate in the up-down direction around the central axis r1 extending in parallel with the Y axis. do. As a result, twisting moments in opposite directions are generated about the central axis r1 and bending vibration is generated in the vibrating portion 120. At this time, the strain is concentrated in the region near the central axis r1 in the base 130.

FIG. 5 is a diagram for explaining the operation of the vibrating portion 120 during bending vibration. As shown in the figure, during the bending vibration of the vibrating portion 120, the first rotation moment Arm, the second rotation moment Bend, and the third rotation moment All are generated. The first rotational moment Arm is a rotational moment around the central axis parallel to the Y axis. The second rotational moment Bend is a rotational moment around the central axis parallel to the X axis passing through the connection portion between the vibrating arm 135 and the base 130. The third rotational moment All is a rotational moment around the central axis parallel to the Y axis that passes through the central position of the base 130 in the X-axis direction.

FIG. 6 is a diagram showing an example of the resonator 10 according to the embodiment. As shown in the figure, the first vibrating arm 135A is a vibrating portion 120 of the first vibrating arm 135A and the second vibrating arm 135B in the parallel direction with respect to the first central axis S1 extending in the longitudinal direction of the first vibrating arm 135A. It has a first offset structure that offsets the center of gravity position G1 of the first vibrating arm 135A inside. Further, the second vibrating arm 135B has a second vibration inside the vibrating portion 120 in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B with respect to the second central axis S2 extending in the longitudinal direction of the second vibrating arm 135B. It has a second offset structure that offsets the center of gravity position G2 of the arm 135B. The first central axis S1 is the central axis in the lateral direction of the first vibrating arm 135A at the boundary portion between the first vibrating arm 135A and the base 130. The first central axis S1 is a straight line parallel to the Y axis passing through the center position of the first vibrating arm 135A on the straight line AA'parallel to the X axis passing through the boundary portion between the first vibrating arm 135A and the base 130. be. The second central axis S2 is the central axis in the lateral direction of the second vibrating arm 135B at the boundary portion between the second vibrating arm 135B and the base 130. The second central axis S2 is a straight line parallel to the Y axis passing through the center position of the second vibrating arm 135B on the straight line AA'parallel to the X axis passing through the boundary portion between the second vibrating arm 135B and the base 130. be.

In the illustrated example, the first offset structure is provided at the tip of the first vibrating arm 135A, and the second offset structure is provided at the tip of the second vibrating arm 135B. The tip of the first vibrating arm 135A is, for example, a portion on the tip side of the center position in the longitudinal direction of the first vibrating arm 135A, and the tip of the second vibrating arm 135B is, for example, the second vibrating arm 135B. It is the part on the tip side of the center position in the longitudinal direction. Further, in the illustrated example, the first offset structure is inside the vibrating portion 120 in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B with respect to the first central axis S1 in the upper surface of the first vibrating arm 135A. Includes a weight portion 136A provided in. The weight portion 136A may be provided on the lower surface of the first vibrating arm 135A. Further, the second offset structure is a weight provided inside the vibrating portion 120 in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B from the second central axis S2 on the upper surface of the second vibrating arm 135B. Includes part 136B. The weight portion 136B may be provided on the lower surface of the second vibrating arm 135B.

The weight portion 136A has a rectangular plate shape elongated in the longitudinal direction of the first vibrating arm 135A, and the center position of the weight portion 136A in the X-axis direction is X than the center position of the first vibrating arm 135A in the X-axis direction. It is located inside the vibrating portion 120 in the axial direction. In the illustrated example, although the position at the left end in the X-axis direction of the weight portion 136A is located inside the vibrating portion 120 in the X-axis direction from the center position in the X-axis direction of the first vibrating arm 135A, the weight portion If the center position in the X-axis direction of the 136A is located inside the vibrating portion 120 in the X-axis direction from the center position in the X-axis direction of the first vibrating arm 135A, it is the left end in the X-axis direction of the weight portion 136A. The position may be located outside the vibrating portion 120 in the X-axis direction with respect to the center position in the X-axis direction of the first vibrating arm 135A. The weight portion 136A has a rectangular plate shape elongated in the longitudinal direction of the first vibrating arm 135A, and the center position of the weight portion 136A in the X-axis direction is X than the center position of the first vibrating arm 135A in the X-axis direction. It is located inside the vibrating portion 120 in the axial direction. In the illustrated example, although the position at the left end in the X-axis direction of the weight portion 136A is located inside the vibrating portion 120 in the X-axis direction from the center position in the X-axis direction of the first vibrating arm 135A, the weight portion If the center position in the X-axis direction of the 136A is located inside the vibrating portion 120 in the X-axis direction from the center position in the X-axis direction of the first vibrating arm 135A, it is the left end in the X-axis direction of the weight portion 136A. The position may be located outside the vibrating portion 120 in the X-axis direction with respect to the center position in the X-axis direction of the first vibrating arm 135A.

The weight portion 136B has a rectangular plate shape elongated in the longitudinal direction of the second vibrating arm 135B, and the center position of the weight portion 136B in the X-axis direction is X than the center position of the second vibrating arm 135B in the X-axis direction. It is located inside the vibrating portion 120 in the axial direction. In the illustrated example, although the position at the left end in the X-axis direction of the weight portion 136B is located inside the vibrating portion 120 in the X-axis direction from the center position in the X-axis direction of the second vibrating arm 135B, the weight portion If the center position in the X-axis direction of the 136B is located inside the vibrating portion 120 in the X-axis direction from the center position in the X-axis direction of the second vibrating arm 135B, it is the left end in the X-axis direction of the weight portion 136B. The position may be located outside the vibrating portion 120 in the X-axis direction with respect to the center position in the X-axis direction of the second vibrating arm 135B. The weight portion 136B has a rectangular plate shape elongated in the longitudinal direction of the second vibrating arm 135B, and the center position of the weight portion 136B in the X-axis direction is X than the center position of the second vibrating arm 135B in the X-axis direction. It is located inside the vibrating portion 120 in the axial direction. In the illustrated example, although the position at the left end in the X-axis direction of the weight portion 136B is located inside the vibrating portion 120 in the X-axis direction from the center position in the X-axis direction of the second vibrating arm 135B, the weight portion If the center position in the X-axis direction of the 136B is located inside the vibrating portion 120 in the X-axis direction from the center position in the X-axis direction of the second vibrating arm 135B, it is the left end in the X-axis direction of the weight portion 136B. The position may be located outside the vibrating portion 120 in the X-axis direction with respect to the center position in the X-axis direction of the second vibrating arm 135B.

(6. Function of resonator)
Next, the function of the resonator 10 according to the present embodiment will be described. FIG. 7 is a diagram for explaining the function of the resonator 10 of the comparative example. In the resonator 10 of the comparative example, the position of the center of gravity of the first vibrating arm 135A coincides with the first central axis S1, and the position of the center of gravity of the second vibrating arm 135B coincides with the second central axis S2. FIG. 7 visually shows the result of predicting the magnitude of the distortion generated at each location of the resonator 10 at the time of bending vibration of the resonator 10 in the comparative example using a simulation model. As shown in the figure, at the time of bending vibration of the resonator 10 of the comparative example, the first rotational moment Arm in the same direction acts on each of the tip portion of the first vibrating arm 135A and the tip portion of the second vibrating arm 135B. As a result, the base end portion of the first vibrating arm 135A and the base end portion of the second vibrating arm 135B are likely to be distorted. If these distortions are transmitted from each of the first vibrating arm 135A and the second vibrating arm 135B to the base 130, vibration leakage may occur from the base 130 to the outside, which may affect the vibration characteristics of the vibrating portion 120. rice field.

FIG. 8 is a diagram for explaining the function of the resonator 10 according to the present embodiment. FIG. 8 shows the position of the center of gravity of the first vibrating arm 135A and the position of the center of gravity of the first vibrating arm 135A by bending the tip of the first vibrating arm 135A and the tip of the second vibrating arm 135B inward for convenience of explanation and understanding of the specification. , The case where the position of the center of gravity of the second vibrating arm 135B is offset will be described as an example. As shown in the figure, at the time of bending vibration of the resonator 10 according to the present embodiment, the first rotational moment Arm in the opposite direction acts on each of the tip of the first vibrating arm 135A and the tip of the second vibrating arm 135B. do. As a result, distortion occurs in the base end of the first vibrating arm 135A and the base end of the second vibrating arm 135B, and these distortions are transmitted from each of the first vibrating arm 135A and the second vibrating arm 135B to the base 130. Even if transmitted, these distortions are offset. As a result, vibration leakage from the base 130 to the outside is unlikely to occur, and the vibration characteristics of the vibration unit 120 are stabilized.

The resonator 10 according to the present embodiment is provided between the vibrating portion 120, the holding portion 140 provided at least a part around the vibrating portion 120, and the vibrating portion 120 and the holding portion 140, and one end thereof is a base portion. A holding arm 110 connected to 130 and the other end connected to a holding portion 140 is provided, and the vibrating portion 120 has a fixed end and an open end, and is fixed to a first vibrating arm 135A that bends out of the plane. The second vibrating arm 135B, which has an end and an open end and bends out of the plane in a phase different from that of the first vibrating arm 135A, the front end connected to the first vibrating arm 135A and the second vibrating arm 135B, and the front end thereof. The first vibrating arm 135A includes a base 130 having opposite rear ends, and the first vibrating arm 135A is larger than the first central axis S1 in the lateral direction of the first vibrating arm 135A at the boundary portion between the first vibrating arm 135A and the base 130. The second vibrating arm 135B has a first offset structure for offsetting the center of gravity position G1 of the first vibrating arm 135A inside the vibrating portion 120 in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B. Inside the vibrating portion 120 in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B than the second central axis S2 in the lateral direction of the second vibrating arm 135B at the boundary portion between the vibrating arm 135B and the base 130. 2 It has a second offset structure that offsets the center of gravity position G2 of the vibrating arm 135B. Therefore, when the resonator 10 bends and vibrates, the distortion transmitted from each of the first vibrating arm 135A and the second vibrating arm 135B to the base 130 is canceled out. As a result, vibration leakage from the base 130 to the outside is unlikely to occur, and the vibration characteristics of the vibration unit 120 can be stabilized.

FIG. 9 is a diagram showing a modified example of the configuration of the resonator according to the embodiment. Specifically, the first offset structure includes a convex portion 137A provided on the side surface of the first vibrating arm 135A facing the second vibrating arm 135B in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B. .. The second offset structure includes a convex portion 137B provided on the side surface of the second vibrating arm 135B facing the first vibrating arm 135A in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B.

FIG. 10 is a diagram showing a modified example of the configuration of the resonator according to the embodiment. In this example, the first offset structure is located outside the vibrating portion 120 of the upper surface or the lower surface of the first vibrating arm 135A in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B with respect to the first central axis S1. Includes the formed hole 138A. In the first offset structure, instead of the hole 138A, of the upper surface or the lower surface of the first vibrating arm 135A, the vibrating portion 120 in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B from the first central axis S1. It may include a groove formed on the outside. The second offset structure is a hole formed in the upper surface or the lower surface of the second vibrating arm 135B on the outer side of the vibrating portion 120 in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B with respect to the second central axis S2. 138B is included. In the second offset structure, instead of the hole 138B, of the upper surface or the lower surface of the second vibrating arm 135B, the vibrating portion 120 in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B from the first central axis S1. It may include a groove formed on the outside.

FIG. 11 is a diagram showing a modified example of the configuration of the resonator according to the embodiment. In this example, the first offset structure is the first vibrating arm 135A opposite to the side surface of the first vibrating arm 135A facing the second vibrating arm 135B in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B. Includes a recess 139A provided on the side surface of the. The second offset structure is provided on the side surface of the second vibrating arm 135B opposite to the side surface of the second vibrating arm 135B facing the first vibrating arm 135A in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B. Includes the recessed 139B.

FIG. 12 is a diagram showing a modified example of the configuration of the resonator according to the embodiment. In this example, the first offset structure is the first convex portion 141A provided on the side surface of the first vibrating arm 135A facing the second vibrating arm 135B in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B. , The first convex is provided on the side surface of the first vibrating arm 135A opposite to the side surface of the first vibrating arm 135A facing the second vibrating arm 135B in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B. It includes a second convex portion 142A having a smaller protrusion amount from the side surface of the first vibrating arm 135A than the portion 141A. The second offset structure includes a first convex portion 141B provided on the side surface of the second vibrating arm 135B facing the first vibrating arm 135A in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B, and the first vibration. It is provided on the side surface of the second vibrating arm 135B opposite to the side surface of the second vibrating arm 135B facing the first vibrating arm 135A in the parallel direction of the arm 135A and the second vibrating arm 135B, and is more than the first convex portion 141B. It includes a second convex portion 142B having a small protrusion amount from the side surface of the second vibrating arm 135B.

FIG. 13 is a diagram showing a modified example of the configuration of the resonator according to the embodiment. In this example, the first offset structure is on the side surface of the first vibrating arm 135A facing the second vibrating arm 135B in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B in the longitudinal direction of the first vibrating arm 135A. It includes a plurality of convex portions 143A provided at intervals. The second offset structure includes a protrusion 143B provided on the side surface of the second vibrating arm 135B facing the first vibrating arm 135A in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B. The convex portion 143B is provided at a position intermediate between the plurality of convex portions 143A in the longitudinal direction of the second vibrating arm 135B. In this example, the first offset structure and the second offset structure are asymmetrical to each other, but the first vibrating arm 135A and the second vibrating arm 135B have a common natural frequency.

FIG. 14 is a diagram showing a modified example of the configuration of the resonator according to the embodiment. In this example, the first offset structure is on the side surface of the first vibrating arm 135A facing the second vibrating arm 135B in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B in the longitudinal direction of the first vibrating arm 135A. It includes a plurality of convex portions 144A provided at intervals and a concave portion 145A provided at an intermediate position between the plurality of convex portions 144A in the same direction. The second offset structure has a convex portion 144B provided on the side surface of the second vibrating arm 135B facing the first vibrating arm 135A in the parallel direction of the first vibrating arm 135A and the second vibrating arm 135B. It includes a plurality of recesses 145B provided on both sides of the 144B. The tip of each of the plurality of protrusions 144A is arranged inside the plurality of recesses 145B. The tip of the convex portion 144B is arranged inside the concave portion 145A. In this example, the first offset structure and the second offset structure are asymmetrical to each other, but the first vibrating arm 135A and the second vibrating arm 135B have a common natural frequency.

FIG. 15 is a diagram showing a modified example of the configuration of the resonator according to the embodiment. In this example, the first central axis S1 extending in the longitudinal direction of the first vibrating arm 135A and the second central axis S2 extending in the longitudinal direction of the second vibrating arm 135B are the first vibrating arm 135A and the second vibration, respectively. The arm 135B is inclined and extends inward of the vibrating portion 120 in the parallel direction. In this case, the first central axis S1 passes through the center position of the first vibrating arm 135A on the straight line AA'parallel to the X axis passing through the boundary portion between the first vibrating arm 135A and the base 130. It is a straight line parallel to the longitudinal direction of 135A. The second central axis S2 is the longitudinal length of the second vibrating arm 135B passing through the center position of the second vibrating arm 135B on the straight line AA'parallel to the X axis passing through the boundary portion between the second vibrating arm 135B and the base 130. It is a straight line parallel to the direction.

Hereinafter, a part or all of the embodiments of the present invention will be described and their effects will be described. The present invention is not limited to the following appendices.

According to one aspect of the present invention, the vibrating portion is provided with a vibrating portion, a holding portion provided at least a part around the vibrating portion, and a holding arm provided between the vibrating portion and the holding portion. Has a first vibrating arm that has a fixed end and an open end and bends out of the plane, and a second vibrating arm that has a fixed end and an open end and bends out of the plane in a phase different from that of the first vibrating arm. The holding arm includes a front end connected to a first vibrating arm and a second vibrating arm, and a base having a rear end facing the front end, the holding arm having one end connected to the base and the other end connected to the holding portion. The first vibrating arm is inside the vibrating portion in the parallel direction of the first vibrating arm and the second vibrating arm from the first central axis in the lateral direction of the first vibrating arm at the boundary portion between the first vibrating arm and the base. It has a first offset structure that offsets the position of the center of gravity of the first vibrating arm, and the second vibrating arm is more than the second central axis in the lateral direction of the second vibrating arm at the boundary between the second vibrating arm and the base. Provided is a resonator having a second offset structure for offsetting the position of the center of gravity of the second vibrating arm inside the vibrating portion in the parallel direction of the first vibrating arm and the second vibrating arm.

As one aspect, the first offset structure is provided at the tip of the first vibrating arm, and the second offset structure is provided at the tip of the second vibrating arm.

As one aspect, the first offset structure is a weight portion provided inside the vibrating portion of the upper surface or the lower surface of the first vibrating arm in the parallel direction of the first vibrating arm and the second vibrating arm with respect to the first central axis. The second offset structure includes a weight portion provided inside the vibrating portion of the upper surface or the lower surface of the second vibrating arm in the parallel direction of the first vibrating arm and the second vibrating arm with respect to the second central axis. include.

As one embodiment, the first offset structure includes a convex portion provided on the side surface of the first vibrating arm facing the second vibrating arm in the parallel direction of the first vibrating arm and the second vibrating arm, and the second offset structure is , Includes a convex portion provided on the side surface of the second vibrating arm facing the first vibrating arm in the parallel direction of the first vibrating arm and the second vibrating arm.

As one aspect, the first offset structure is a hole or a hole formed on the outer surface of the upper surface or the lower surface of the first vibrating arm in the parallel direction of the first vibrating arm and the second vibrating arm with respect to the first central axis. The second offset structure includes a groove, or a hole or a hole formed on the outer surface of the upper surface or the lower surface of the second vibrating arm in the parallel direction of the first vibrating arm and the second vibrating arm with respect to the second central axis. Including grooves.

As one aspect, the first offset structure is provided on the side surface of the first vibrating arm opposite to the side surface of the first vibrating arm facing the second vibrating arm in the parallel direction of the first vibrating arm and the second vibrating arm. The second offset structure is provided on the side surface of the second vibrating arm opposite to the side surface of the second vibrating arm facing the first vibrating arm in the parallel direction of the first vibrating arm and the second vibrating arm. Includes recessed recesses.

As one aspect, the first offset structure has a first convex portion provided on the side surface of the first vibrating arm facing the second vibrating arm in the parallel direction of the first vibrating arm and the first vibrating arm, and the first vibrating arm. And from the side surface of the first vibrating arm rather than the first convex portion provided on the side surface of the first vibrating arm opposite to the side surface of the first vibrating arm facing the second vibrating arm in the parallel direction of the second vibrating arm. The second offset structure is provided on the side surface of the second vibrating arm facing the first vibrating arm in the parallel direction of the first vibrating arm and the second vibrating arm, including the second convex portion having a small protrusion amount. The first convex portion is provided on the side surface of the second vibrating arm opposite to the side surface of the second vibrating arm facing the first vibrating arm in the parallel direction of the first vibrating arm and the first vibrating arm. It includes a second convex portion having a smaller protrusion amount from the side surface of the second vibrating arm.

As one aspect, the first vibrating arm and the second vibrating arm have a common natural frequency, and the first offset structure and the second offset structure are asymmetrical with each other.

According to one aspect of the present invention, the vibrating portion is provided with a vibrating portion, a holding portion provided at least a part around the vibrating portion, and a holding arm provided between the vibrating portion and the holding portion. Has a first vibrating arm that has a fixed end and an open end and bends out of the plane, and a second vibrating arm that has a fixed end and an open end and bends out of the plane in a phase different from that of the first vibrating arm. The holding arm includes a front end connected to a first vibrating arm and a second vibrating arm, and a base having a rear end facing the front end, the holding arm having one end connected to the base and the other end connected to the holding portion. , The first central axis in the lateral direction of the first vibrating arm at the boundary between the first vibrating arm and the base, and the second in the lateral direction of the second vibrating arm at the interface between the second vibrating arm and the base. Each of the central axes is inclined and extends inward of the vibrating portion in the parallel direction of the first vibrating arm and the second vibrating arm.

As one aspect, the vibrating portion has a piezoelectric film and an upper electrode and a lower electrode provided so as to face each other with the piezoelectric film interposed therebetween.

As described above, according to one aspect of the present invention, the vibration characteristics of the vibrating portion can be stabilized by canceling the rotational moment around the central axis extending in the longitudinal direction of the vibrating arm.

-In the above embodiment, the case where the resonator is a MEMS having a piezoelectric film and an upper electrode and a lower electrode provided so as to face each other across the piezoelectric film has been described as an example, but the resonator is described. Not limited to this, it may have other materials (for example, crystal material, etc.) and structures.

It should be noted that the embodiments described above are for facilitating the understanding of the present invention, and are not for limiting the interpretation of the present invention. The present invention can be modified / improved without departing from the spirit thereof, and the present invention also includes an equivalent thereof. That is, those skilled in the art with appropriate design changes to each embodiment are also included in the scope of the present invention as long as they have the features of the present invention. For example, each element included in each embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those exemplified, and can be appropriately changed. Further, the elements included in each embodiment can be combined as much as technically possible, and the combination thereof is also included in the scope of the present invention as long as the features of the present invention are included.

1 Resonator 10 Resonator 20 Lower lid 30 Upper lid 110 Holding arm 120 Vibrating part 130 Base 135 Vibrating arm 135A 1st vibrating arm 135B

2nd vibrating arm

136A,

136B Weight part

137A,

137B Convex part

138A,

138B Hole

139A, 139B Concave 140 Holding part 140a-

d Frame body

141A, 141B First

convex part

142A, 142B Second

convex part

143A,

143B Convex part

144A,

144B Convex part

145A, 145B Concave part 235 Protective film 236 Frequency adjustment film

Claims

The vibrating part and
A holding portion provided at least a part around the vibrating portion and a holding portion.
A holding arm provided between the vibrating portion and the holding portion,
Equipped with
The vibrating part is
A first vibrating arm that has a fixed end and an open end and bends out of the plane,
A second vibrating arm that has a fixed end and an open end and bends out of the plane in a phase different from that of the first vibrating arm.
A front end to which the first vibrating arm and the second vibrating arm are connected in parallel, and a base having a rear end facing the front end,
Including
One end of the holding arm is connected to the base and the other end is connected to the holding portion.
The first vibrating arm is in the parallel direction of the first vibrating arm and the second vibrating arm with respect to the first central axis in the lateral direction of the first vibrating arm at the boundary between the first vibrating arm and the base. It has a first offset structure that offsets the position of the center of gravity of the first vibrating arm inside the vibrating portion.
The second vibrating arm is located inside the vibrating portion in the parallel direction from the second central axis in the lateral direction of the second vibrating arm at the boundary between the second vibrating arm and the base portion. Has a second offset structure that offsets the position of the center of gravity of
Resonator.
The first offset structure is provided at the tip of the first vibrating arm.
The second offset structure is provided at the tip of the second vibrating arm.
The resonator according to claim 1.
The first offset structure includes a weight portion of the upper surface or the lower surface of the first vibrating arm provided inside the vibrating portion in the parallel direction from the first central axis.
The second offset structure includes a weight portion of the upper surface or the lower surface of the second vibrating arm provided inside the vibrating portion in the parallel direction from the second central axis.
The resonator according to claim 1 or 2.
The first offset structure includes a protrusion provided on the side surface of the first vibrating arm facing the second vibrating arm in the parallel direction.
The second offset structure includes a protrusion provided on the side surface of the second vibrating arm facing the first vibrating arm in the parallel direction.
The resonator according to claim 1 or 2.
The first offset structure includes a hole or groove formed on the outer surface of the vibrating portion in the parallel direction from the first central axis on the upper surface or the lower surface of the first vibrating arm.
The second offset structure includes a hole or groove formed on the outer surface of the vibrating portion in the parallel direction from the second central axis on the upper surface or the lower surface of the second vibrating arm.
The resonator according to claim 1 or 2.
The first offset structure includes a recess provided on the side surface of the first vibrating arm opposite to the side surface of the first vibrating arm facing the second vibrating arm in the parallel direction.
The second offset structure includes a recess provided on the side surface of the second vibrating arm opposite to the side surface of the second vibrating arm facing the first vibrating arm in the parallel direction.
The resonator according to claim 1 or 2.
The first offset structure includes a first convex portion provided on the side surface of the first vibrating arm facing the second vibrating arm in the parallel direction, and the first convex portion facing the second vibrating arm in the parallel direction. 1 Includes a second convex portion provided on the side surface of the first vibrating arm opposite to the side surface of the vibrating arm and having a smaller protrusion amount from the side surface of the first vibrating arm than the first convex portion.
The second offset structure includes a first convex portion provided on the side surface of the second vibrating arm facing the first vibrating arm in the parallel direction, and the first convex portion facing the first vibrating arm in the parallel direction. 2. Includes a second convex portion provided on the side surface of the second vibrating arm opposite to the side surface of the vibrating arm and having a smaller protrusion amount from the side surface of the second vibrating arm than the first convex portion.
The resonator according to claim 1 or 2.
The first vibrating arm and the second vibrating arm have a common natural frequency.
The first offset structure and the second offset structure are asymmetrical with each other.
The resonator according to any one of claims 1 to 7.
The vibrating part and
A holding portion provided at least a part around the vibrating portion and a holding portion.
A holding arm provided between the vibrating portion and the holding portion,
Equipped with
The vibrating part is
A first vibrating arm that has a fixed end and an open end and bends out of the plane,
A second vibrating arm that has a fixed end and an open end and bends out of the plane in a phase different from that of the first vibrating arm.
A front end to which the first vibrating arm and the second vibrating arm are connected in parallel, and a base having a rear end facing the front end,
Including
One end of the holding arm is connected to the base and the other end is connected to the holding portion.
The first central axis in the lateral direction of the first vibrating arm at the boundary portion between the first vibrating arm and the base portion, and the short length of the second vibrating arm at the boundary portion between the second vibrating arm and the base portion. Each of the second central axes in the hand direction is inclined and extends inward of the vibrating portion in the parallel direction of the first vibrating arm and the second vibrating arm.
Resonator.
The vibrating part is
Piezoelectric membrane and
It has an upper electrode and a lower electrode provided so as to face each other with the piezoelectric film interposed therebetween.
The resonator according to any one of claims 1 to 9.
The resonator according to any one of claims 1 to 10 and
The upper lid and the lower lid provided so as to face each other with the resonator in between,
To prepare
Resonator.