Vibration elements, vibrators and oscillators

Abstract

To provide a vibration element capable of presenting excellent vibration characteristics with low power consumption, a vibrator comprising the vibration element, an oscillator, an electronic apparatus and a mobile.SOLUTION: A vibration element 2 comprises a crystal substrate 3 including a base 4, a pair of vibration arms 5 and 6 extending from the base 4 and a support arm 71 extending, between the vibration arms 5 and 6, from the base 4 to the same side as them. The vibration arm 5 includes an arm part 51 and a hammer head 59 which is provided in a tip end of the arm part 51. The arm part 51 includes a pair of principal surfaces and a bottomed groove which is opened on the principal surfaces. A width of bank parts which are disposed side by side while interposing the groove therebetween in a width direction orthogonal to a length direction of the vibration arms on the principal surfaces is set equal to or less than 6 μm.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vibration element, a vibrator, an oscillator, an electronic device, and a moving object. [Background technology]

[0002] Conventionally, vibration elements using quartz crystal have been known (see, for example, Patent Document 1). Such vibration elements have excellent frequency-temperature characteristics and are therefore widely used as reference frequency sources and transmission sources for various electronic devices. The vibration element described in Patent Document 1 is of a tuning fork type, and has a base and a pair of vibration arms extending from the base. Each of the vibration arms has a pair of grooves that open to the upper and lower surfaces. Therefore, each of the vibration arms has a substantially H-shaped cross section. By forming the vibration arms in this shape, it is possible to reduce thermoelastic loss and to exhibit excellent vibration characteristics. However, in the past, the shape (including the size) of the vibration arms around the grooves has not been sufficiently studied. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 2-32229 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a vibration element that can exhibit excellent vibration characteristics with low power consumption, and a vibrator, an oscillator, an electronic device, and a mobile object that include this vibration element. [Means for solving the problem]

[0005] The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following application examples. [Application example 1] The vibration element of the present invention includes a base portion including a first end portion and a second end portion opposite to the first end portion in a plan view; a pair of vibration arms that are integrally provided with the base, extend from the base along a first direction on the first end side of the base, and are aligned along a second direction perpendicular to the first direction; Each of the vibrating arms is The arm and a wide portion located on the opposite side of the arm portion from the base portion side and having a length along the second direction greater than that of the arm portion, Each of the vibrating arms is A pair of main surfaces in a front-back relationship; a bottomed groove provided on each of the main surfaces; The width of each of the portions arranged on the main surface of each of the arms along the second direction on either side of the groove is 6 μm or less. This makes it possible to sufficiently reduce the equivalent series resistance R1 (CI value) while maintaining a relatively high Q value of the vibration element. As a result, it is possible to obtain a vibration element that can exhibit excellent vibration characteristics with low power consumption.

[0006] [Application example 2] In the vibration element of the present invention, it is preferable that the width is not less than 1 μm and not more than 3 μm. This makes it possible to reduce R1 (CI value) of the vibration element, and thus to drive the vibration element with lower power consumption. [Application example 3] In the vibration element of the present invention, the maximum depth of the groove is t [μm], When the thickness of the vibrating arm is T [μm], It is preferable that η expressed as 2t / T is 0.6 or more. This allows the formation area of ​​the driving electrodes to be increased, so that R1 (CI value) of the vibration element can be made smaller, resulting in a vibration element with lower power consumption. [Application example 4] In the vibration element of the present invention, it is preferable that the thickness of the vibrating arm is 50 μm or more. This allows the R1 of the vibration element to be made smaller.

[0007] [Application example 5] The vibration element of the present invention preferably includes a support portion supporting the base portion. This makes it possible to more effectively reduce vibration leakage from the vibration element. [Application Example 6] In the vibration element according to the aspect of the invention, it is preferable that the support portion includes a support arm extending from the base portion along the first direction between the pair of vibration arms. This makes it possible to more effectively reduce vibration leakage from the vibration element.

[0008] [Application Example 7] In the vibration element according to the aspect of the invention, it is preferable that the support portion includes a support arm extending from the base portion on a side of the second end portion of the base portion. This makes it possible to more effectively reduce vibration leakage from the vibration element. Also, since there is no need to provide a support arm between the vibration arms, the length (width) of the vibration element in the second direction can be made small.

[0009] [Application Example 8] In the vibration element according to the present invention, it is preferable that the support portion includes a frame body that surrounds at least the base portion, the vibrating arms, and the supporting arms and is connected to the supporting arms. This allows the vibration element to be fixed to, for example, the base of a package with high accuracy via the frame, which allows the size of the vibration element to be increased, and as a result, the R1 can be made smaller.

[0010] [Application Example 9] In the vibration element according to the present invention, it is preferable that the support portion includes a frame surrounding at least the base portion and the vibrating arms. This allows the vibration element to be fixed to, for example, the base of a package with high accuracy via the frame, which allows the size of the vibration element to be increased, and as a result, the R1 can be made smaller.

[0011] [Example 10] In the vibration element of the present invention, it is preferable that the base includes a narrowing portion on at least one of the first end side and the second end side, the length along the second direction being continuously or stepwise reduced as it moves away from the center of the base along the center line between the pair of vibrating arms. By providing the base portion with the reduced width portion, vibration leakage from the vibration element can be effectively suppressed.

[0012] [Application Example 11] The vibrator of the present invention comprises the vibration element of the present invention and and a package in which the vibration element is mounted. This provides a highly reliable vibrator.

[0013] [Example 12] The oscillator of the present invention comprises: and an oscillator circuit. This results in a highly reliable oscillator.

[0014] [Application Example 13] An electronic device according to the present invention includes the vibration element according to the present invention. This makes it possible to obtain highly reliable electronic equipment. [Example 14] A moving object according to the present invention is characterized by including the vibration element according to the present invention. This makes it possible to obtain a highly reliable mobile body. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a plan view of a vibrator according to a first embodiment of the present invention. [Diagram 2]2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] FIG. 4 is a plan view illustrating the principle of vibration leakage reduction. [Figure 4] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Diagram 5] 11 is a cross-sectional view of a vibrating arm for explaining heat conduction during bending vibration. FIG. [Figure 6] 1 is a graph showing the relationship between the Q value and f / fm. [Figure 7] FIG. 11 is a cross-sectional view showing a vibrating arm formed by wet etching. [Figure 8] 13 is a graph showing the relationship between W3 and the Q value. [Figure 9] 1 is a graph showing the relationship between W3 and 1 / R1. [Figure 10] 11 is a plan view of a vibration element included in a vibrator according to a second embodiment of the present invention. FIG. [Figure 11] FIG. 11 is a plan view of a vibrator according to a third embodiment of the present invention. [Figure 12] 12 is a cross-sectional view taken along line CC in FIG. 11. [Figure 13] 13 is a plan view of a vibration element included in a vibrator according to a fourth embodiment of the present invention. FIG. [Figure 14] 1 is a cross-sectional view showing a preferred embodiment of an oscillator of the present invention. [Figure 15] FIG. 1 is a perspective view showing the configuration of a mobile (or notebook) personal computer to which an electronic device equipped with a vibration element of the present invention is applied. [Figure 16] FIG. 1 is a perspective view showing a configuration of a mobile phone (including a PHS) to which an electronic device having a vibration element of the present invention is applied. [Figure 17] 1 is a perspective view showing a configuration of a digital still camera to which an electronic device having a vibration element of the present invention is applied. [Figure 18] 1 is a perspective view showing a schematic view of an automobile as an example of a moving body according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vibration element, a vibrator, an oscillator, an electronic device, and a moving object according to the present invention will be described in detail below with reference to preferred embodiments shown in the drawings. First, a vibrator to which the vibration element of the present invention is applied (the vibrator of the present invention) will be described. First Embodiment Fig. 1 is a plan view of a vibrator according to a first embodiment of the present invention, Fig. 2 is a cross-sectional view taken along line AA in Fig. 1, Fig. 3 is a plan view illustrating the principle of vibration leakage reduction, Fig. 4 is a cross-sectional view taken along line BB in Fig. 1, Fig. 5 is a cross-sectional view of a vibrating arm illustrating heat conduction during bending vibration, Fig. 6 is a graph showing the relationship between the Q value and f / fm, Fig. 7 is a cross-sectional view showing a vibrating arm formed by wet etching, Fig. 8 is a graph showing the relationship between W3 and the Q value, and Fig. 9 is a graph showing the relationship between W3 and 1 / R1. Note that, for convenience of explanation, in the following, the three mutually orthogonal axes are the X-axis (electrical axis of quartz), the Y-axis (mechanical axis of quartz), and the Z-axis (optical axis of quartz) as shown in Fig. 1.

[0017] 1. Transducer 1 and 2 has a vibration element 2 (the vibration element of the present invention) and a package 9 that houses the vibration element 2. Below, the vibration element 2 and the package 9 will be described in detail one by one. (Vibration element 2) 1, 2, and 4, the vibration element 2 has a quartz crystal substrate 3, and first and second driving electrodes 84, 85 formed on the quartz crystal substrate 3. For convenience of explanation, the first and second driving electrodes 84, 85 are not shown in FIGS. 1 and 2. The quartz crystal substrate 3 is made of a Z-cut quartz crystal plate. This allows the vibration element 2 to exhibit excellent vibration characteristics. A Z-cut quartz crystal plate is a quartz crystal substrate whose thickness direction is the Z-axis. It is preferable that the Z-axis coincides with the thickness direction of the quartz crystal substrate 3, but from the viewpoint of reducing the frequency temperature change near room temperature, the Z-axis may be slightly tilted with respect to the thickness direction.

[0018] In other words, when the tilt angle is θ degrees (-5 degrees≦θ≦15 degrees), the X-axis of an orthogonal coordinate system consisting of the X-axis as the electrical axis of the quartz, the Y-axis as the mechanical axis, and the Z-axis as the optical axis is set as the rotation axis, the Z'-axis is set as the axis tilted θ degrees so that the +Z side of the Z-axis rotates in the -Y direction of the Y-axis, and the Y'-axis is set as the axis tilted θ degrees so that the +Y side rotates in the +Z direction of the Z-axis, the thickness is in the direction along the Z'-axis, and the quartz substrate 3 has a surface including the X-axis and Y'-axis as its main surface.

[0019] 1, the quartz crystal substrate 3 has a base 4, a pair of vibrating arms 5 and 6 extending from the base 4 at the tip (first end) side of the base 4, and a support arm (support portion) 71 extending from the base 4 between the vibrating arms 5 and 6 on the same side as the vibrating arms 5 and 6. Therefore, the base 4, the vibrating arms 5 and 6, and the support arm 71 are integrally formed. The base 4 is in the form of a plate having an extent in the XY plane and a thickness in the Z-axis direction. The base 4 has a portion (main body portion 41) that supports and connects the vibrating arms 5 and 6, and a reduced width portion 42 that reduces vibration leakage.

[0020] The reduced width portion 42 is provided on the base end (second end) side of the main body 41, i.e., on the opposite side to the side where the vibrating arms 5 and 6 extend. The reduced width portion 42 has a width (length along the X-axis direction) that gradually decreases along the center line C1 between the vibrating arms 5 and 6, i.e., away from the center of the base 4 (main body 41), and has an arch-shaped (circular-arc-shaped) contour (edge). By having such a reduced width portion 42, vibration leakage from the vibration element 2 can be effectively suppressed.

[0021] A more specific description is given as follows: For ease of explanation, the shape of the vibration element 2 is assumed to be symmetrical with respect to a predetermined axis (center line C1) parallel to the Y axis. First, a description will be given of a case where the contracted portion 42 is not provided, as shown in Fig. 3(a). When the vibrating arms 5 and 6 are bent and deformed so as to move away from each other, a displacement close to a clockwise rotational motion as indicated by the arrow occurs in the main body 41 in the vicinity of the connection of the vibrating arm 5, and a displacement close to a counterclockwise rotational motion as indicated by the arrow occurs in the main body 41 in the vicinity of the connection of the vibrating arm 6 (however, strictly speaking, this is not a motion that can be called a rotational motion, so for convenience it will be referred to as "close to a rotational motion").

[0022] Since the X-axis components of these displacements are in opposite directions, they are offset at the center of the X-axis direction of the main body 41, and the displacement in the +Y-axis direction remains (though strictly speaking, the displacement in the Z-axis direction also remains, but this is omitted here). That is, the main body 41 is bent and deformed such that the center of the X-axis direction is displaced in the +Y-axis direction. The support arm 71 extends from the main body 41, which has the displacement in the +Y-axis direction, and the support arm 71 moves with a displacement in the +Y-axis direction. Therefore, if an adhesive is applied to the support arm 71 and the support arm 71 is fixed to the package via the adhesive, the elastic energy accompanying the displacement in the +Y-axis direction leaks out through the adhesive. This is a loss called vibration leakage, which causes a deterioration in the Q value and, as a result, a deterioration in the CI value.

[0023] On the other hand, as shown in FIG. 3(b), when the reduced width portion 42 is provided, the reduced width portion 42 has an arched (curved) contour, so that the displacements similar to the above-mentioned rotational movement are blocked by each other at the reduced width portion 42. That is, at the center of the reduced width portion 42 in the X-axis direction, the displacement in the X-axis direction is offset in the same manner as at the center of the main body portion 41 in the X-axis direction, and the displacement in the Y-axis direction is suppressed. Furthermore, since the contour of the reduced width portion 42 is arched, the displacement in the +Y-axis direction that is about to occur at the main body portion 41 is also suppressed. As a result, the displacement in the +Y-axis direction at the center of the X-axis direction of the base portion 4 in the case where the reduced width portion 42 is provided is much smaller than that in the case where the reduced width portion 42 is not provided. That is, a vibration element with small vibration leakage can be obtained.

[0024] Here, the contour of the reduced width portion 42 is arch-shaped, but is not limited thereto as long as it exhibits the above-mentioned action. For example, the reduced width portion may be a reduced width portion whose width decreases stepwise along the center line C1 in plan view and whose contour is formed in a stepped (stepped) shape by multiple straight lines, a reduced width portion whose width decreases linearly (continuously) along the center line C1 in plan view and whose contour is formed in a mountain shape (triangular shape) by two straight lines, a reduced width portion whose width decreases linearly (continuously) along the center line C1 in plan view and whose contour is formed by three or more straight lines, etc.

[0025] The vibrating arms 5, 6 are aligned in the X-axis direction (second direction) and extend from the tip of the base 4 along the Y-axis direction (first direction) so as to be parallel to each other. Each of the vibrating arms 5, 6 has an elongated shape with a fixed base end and a free tip. Each of the vibrating arms 5, 6 has an arm 51, 61 and a hammer head (a wide portion having a longer length along the X-axis direction than the arm 51, 61) 59, 69 that is provided at the tip of the arm 51, 61 (opposite the base 4) and has a substantially rectangular shape when viewed in the XY plane.

[0026] 4, the arm 51 has a pair of main surfaces 511, 512 formed in the XY plane, and a pair of side surfaces 513, 514 formed in the YZ plane and connecting the pair of main surfaces 511, 512. The arm 51 also has a bottomed groove 52 that opens to the main surface 511, and a bottomed groove 53 that opens to the main surface 512. Each of the grooves 52, 53 extends in the Y-axis direction, with a tip located at the boundary between the arm 51 and the hammer head 59, and a base located at the base 4. The arm 51 has a substantially H-shaped cross section at the portion where the grooves 52, 53 are formed.

[0027] In this way, by forming the grooves 52 and 53 in the vibrating arm 5, it is possible to reduce thermoelastic loss and exhibit excellent vibration characteristics (described in detail later). The length of the grooves 52 and 53 is not limited, and the tip of each groove 52 and 53 may be located at the boundary between the arm portion 51 and the hammer head 59 as in this embodiment, but if the tip of each groove 52 and 53 is configured to extend to the hammer head 59, the stress concentration occurring around the tip of each groove 52 and 53 is alleviated, so the risk of breaking or chipping occurring when an impact is applied is reduced. Alternatively, if the tip of each groove 52 and 53 is configured to be located closer to the base than in this embodiment, the stress concentration occurring near the boundary between the arm portion 51 and the hammer head 59 is alleviated, so the risk of breaking or chipping occurring when an impact is applied is reduced.

[0028] In addition, by extending the base ends of the grooves 52 and 53 to the base 4, stress concentration at these boundaries is alleviated, thereby reducing the risk of breakage or chipping when an impact is applied. Alternatively, by configuring the base ends of the grooves 52 and 53 to be located in the Y-axis direction (the direction in which the vibrating arms 5 extend) further than the boundary between the base 4 and the arm 51, stress concentration occurring near the boundary between the base 4 and the arm 51 is alleviated, thereby reducing the risk of breakage or chipping when an impact is applied.

[0029] It is preferable that the grooves 52, 53 are formed by adjusting the positions of the grooves 52, 53 in the X-axis direction relative to the position of the vibrating arm 5 so that the cross-sectional center of gravity of the vibrating arm 5 coincides with the center of the cross-sectional shape of the vibrating arm 5. This reduces unnecessary vibrations of the vibrating arm 5 (specifically, oblique vibrations having out-of-plane components), thereby reducing vibration leakage. In this case, the generation of unnecessary vibrations is also reduced, so the driving area is relatively increased and the CI value can be reduced. It is also advisable to slightly shift the center of the hammer head 59 in the X-axis direction from the center of the vibrating arm 5 in the X-axis direction. This reduces the vibration in the Z-axis direction of the base 4 that occurs when the vibrating arm 5 twists during bending vibration, thereby suppressing vibration leakage.

[0030] The vibrating arm 5 has been described above. The vibrating arm 6 has the same configuration as the vibrating arm 5. That is, the arm 61 has a pair of main surfaces 611, 612 formed in the XY plane, and a pair of side surfaces 613, 614 formed in the YZ plane and connecting the pair of main surfaces 611, 612. The arm 61 also has a bottomed groove 62 that opens to the main surface 611, and a bottomed groove 63 that opens to the main surface 612. Each of the grooves 62, 63 extends in the Y-axis direction, with a tip located at the boundary between the arm 61 and the hammer head 69, and a base end located at the base 4. The arm 61 has a substantially H-shaped cross section at the portion where the grooves 62, 63 are formed. It is also advisable to slightly shift the center of the hammer head 69 in the X-axis direction from the center of the vibrating arm 6 in the X-axis direction. This reduces the vibration in the Z-axis direction of the base 4 that occurs when the vibrating arm 6 twists during bending vibration, thereby suppressing vibration leakage.

[0031] As shown in FIG. 4, a pair of first driving electrodes 84 and a pair of second driving electrodes 85 are formed on the vibrating arm 5. Specifically, one of the first driving electrodes 84 is formed on the inner surface (side surface) of the groove 52, and the other is formed on the inner surface (side surface) of the groove 53. Also, one of the second driving electrodes 85 is formed on the side surface 513, and the other is formed on the side surface 514. Similarly, a pair of first driving electrodes 84 and a pair of second driving electrodes 85 are formed on the vibrating arm 6. Specifically, one of the first driving electrodes 84 is formed on the side surface 613, and the other is formed on the side surface 614. Also, one of the second driving electrodes 85 is formed on the inner surface (side surface) of the groove 62, and the other is formed on the inner surface (side surface) of the groove 63. When an alternating voltage is applied between these first and second drive electrodes 84, 85, the vibrating arms 5, 6 vibrate at a predetermined frequency in an in-plane direction (XY plane direction) so as to repeatedly approach and move away from each other.

[0032] The configuration of the first and second driving electrodes 84, 85 is not particularly limited, and may be formed from metal materials such as gold (Au), gold alloy, platinum (Pt), aluminum (Al), aluminum alloy, silver (Ag), silver alloy, chromium (Cr), chromium alloy, nickel (Ni), nickel alloy, copper (Cu), molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt (Co), zinc (Zn), zirconium (Zr), or a conductive material such as indium tin oxide (ITO).

[0033] A specific configuration of the first and second driving electrodes 84, 85 may be, for example, a configuration in which an Au layer of 700 Å or less is formed on a Cr layer of 700 Å or less. In particular, since Cr and Au have large thermoelastic loss, the Cr layer and Au layer are preferably 200 Å or less. Furthermore, in order to increase the dielectric breakdown resistance, the Cr layer and Au layer are preferably 1000 Å or more. Furthermore, since Ni has a thermal expansion coefficient close to that of quartz, by using a Ni layer as the base instead of the Cr layer, the thermal stress caused by the electrodes can be reduced, and a vibration element 2 with good long-term reliability (aging characteristics) can be obtained.

[0034] As described above, in the vibration element 2, the thermoelastic loss is reduced by forming the grooves 52, 53, 62, and 63 in the vibrating arms 5 and 6. Hereinafter, this will be specifically described using the vibrating arm 5 as an example. As described above, the vibrating arm 5 flexurally vibrates in the in-plane direction by applying an alternating voltage between the first and second driving electrodes 84 and 85. As shown in FIG. 5, during this flexural vibration, when the side surface 513 of the arm 51 contracts, the side surface 514 expands, and conversely, when the side surface 513 expands, the side surface 514 contracts. If the vibrating arm 5 does not generate the Gough-Joule effect (energy elasticity is dominant over entropy elasticity), the temperature of the contracting surface side of the side surfaces 513 and 514 increases and the temperature of the expanding surface side decreases, so that a temperature difference occurs between the side surfaces 513 and 514, that is, inside the arm 51. Vibration energy loss occurs due to heat conduction caused by such a temperature difference, and the Q value of the vibration element 2 decreases. Such energy loss accompanying the decrease in the Q value is called thermoelastic loss.

[0035] In a vibration element that vibrates in a bending vibration mode with a configuration like vibration element 2, when the bending vibration frequency (mechanical bending vibration frequency) f of the vibrating arm 5 changes, the Q value becomes minimum when the bending vibration frequency of the vibrating arm 5 coincides with the thermal relaxation frequency fm. This thermal relaxation frequency fm can be calculated as fm = 1 / (2πτ) (where π is the circular constant and e is Napier's constant, τ is the temperature difference caused by thermal conduction e -1 (The relaxation time required for the volume to double.)

[0036] Furthermore, if the thermal relaxation frequency when the vibrating arm 5 is considered to have a flat plate structure (a structure having a rectangular cross-sectional shape) is fm0, fm0 can be obtained by the following formula. fm0 = πk / (2ρCpa 2 ) ... (1) Here, π is the circular constant, k is the thermal conductivity in the vibration direction of the vibrating arm 5, ρ is the mass density of the vibrating arm 5, Cp is the heat capacity of the vibrating arm 5, and a is the width in the vibration direction (effective width) of the vibrating arm 5. When the constants of the material of the vibrating arm 5 itself (i.e., quartz) are input into the thermal conductivity k, mass density ρ, and heat capacity Cp of equation (1), the thermal relaxation frequency fm0 obtained will be the value when the vibrating arm 5 does not have grooves 52 and 53.

[0037] In the vibrating arm 5, grooves 52 and 53 are formed so as to be located between the side surfaces 513 and 514. Therefore, a heat transfer path for achieving temperature equilibrium by thermal conduction of the temperature difference between the side surfaces 513 and 514 generated during flexural vibration of the vibrating arm 5 is formed so as to bypass the grooves 52 and 53, and the heat transfer path is longer than the straight-line distance (shortest distance) between the side surfaces 513 and 514. Therefore, compared to a case in which the grooves 52 and 53 are not provided in the vibrating arm 5, the relaxation time τ becomes longer and the thermal relaxation frequency fm becomes lower.

[0038] 6 is a graph showing the f / fm dependency of the Q value of a vibration element in a bending vibration mode. In the figure, the curve F1 shown by the dotted line shows the case where a groove is formed in the vibration arm like the vibration element 2 (when the cross-sectional shape of the vibration arm is H-shaped), and the curve F2 shown by the solid line shows the case where no groove is formed in the vibration arm (when the cross-sectional shape of the connecting arm is rectangular). As shown in the figure, the shapes of the curves F1 and F2 do not change, but as the thermal relaxation frequency fm decreases as described above, the curve F1 shifts in the frequency decreasing direction relative to the curve F2. Therefore, if the thermal relaxation frequency in the case where grooves are formed in the vibrating arms as in the vibration element 2 is fm1, by satisfying the following formula (2), the Q value of the vibration element in which grooves are formed in the vibrating arms is always higher than the Q value of the vibration element in which grooves are not formed in the vibrating arms.

[0039]

number

[0040] Furthermore, if the relationship f / fm0>1 is satisfied, a higher Q value can be obtained. In FIG. 6, the region where f / fm<1 is also called the isothermal region, and in this isothermal region, the Q value increases as f / fm decreases. This is because the temperature difference in the vibrating arm as described above is less likely to occur as the mechanical frequency of the vibrating arm decreases (the vibration of the vibrating arm becomes slower). Therefore, in the limit where f / fm approaches 0 (zero), the operation becomes isothermal quasi-static, and the thermoelastic loss approaches 0 (zero). On the other hand, the region where f / fm>1 is also called the adiabatic region, and in this adiabatic region, the Q value increases as f / fm increases. This is because, as the mechanical frequency of the vibrating arm increases, the temperature rise and temperature effect of each side switch faster, and there is no time for the thermal conduction to occur as described above. Therefore, in the limit where f / fm is increased infinitely, the operation becomes adiabatic, and the thermoelastic loss approaches 0 (zero). From this, satisfying the relationship of f / fm>1 can be rephrased as f / fm being in the adiabatic region.

[0041] Note that, since the constituent materials (metal materials) of the first and second drive electrodes 84 and 85 have a higher thermal conductivity compared to the quartz that is the constituent material of the vibrating arms 5 and 6, in the vibrating arm 5, heat conduction through the first drive electrode 84 is actively carried out, and in the vibrating arm 6, heat conduction through the second drive electrode 85 is actively carried out. When such heat conduction through the first and second drive electrodes 84 and 85 is actively carried out, the relaxation time τ becomes short. Therefore, in the vibrating arm 5, the first drive electrode 84 is divided into a side surface 513 side and a side surface 514 side at the bottom surfaces of the grooves 52 and 53, and in the vibrating arm 6, the second drive electrode 85 is divided into a side surface 613 side and a side surface 614 side at the bottom surfaces of the grooves 62 and 63, whereby it is preferable to prevent or suppress the occurrence of the above-described heat conduction. As a result, it is possible to prevent the relaxation time τ from becoming short and obtain a vibration element 2 having a higher Q value.

[0042] Next, the relationship between the total lengths of the vibrating arms 5 and 6 and the lengths and widths of the hammer heads 59 and 69 will be described. Since the vibrating arms 5 and 6 have the same configuration as each other, hereinafter, the vibrating arm 5 will be described representatively, and the description of the vibrating arm 6 will be omitted. As shown in FIG. 1, when the total length (length in the Y-axis direction) of the vibrating arm 5 is L [μm] and the length (length in the Y-axis direction) of the hammer head 59 is H [μm], the vibrating arm 5 preferably satisfies the relationship of 0.012 < H / L < 0.3, and more preferably satisfies the relationship of 0.046 < H / L < 0.223. By satisfying such a relationship, the CI value of the vibration element 2 can be kept low, so that the vibration loss is small and the vibration element 2 has excellent vibration characteristics.

[0043] Here, in the present embodiment, the proximal end of the vibrating arm 5 is set at a position at the center of the width (length in the X-axis direction) of the vibrating arm 5 on the line segment connecting the location where the side surface 514 is connected to the base 4 and the location where the side surface 513 is connected to the base 4. Further, the free end of the arm portion 51 has a tapered shape with the width increasing gradually toward the free end side. When the arm portion 51 has a portion where the width (length in the X-axis direction) of this tapered portion is 1.5 times or more the width (length in the X-axis direction) of the arm portion 51, this portion is also included in the length H of the hammer head 59.

[0044] Also, when the width (length in the X-axis direction) of the arm portion 51 of the vibrating arm 5 is W1 [μm] and the width (length in the X-axis direction) of the hammer head 59 is W2 [μm], it is preferably satisfied that 1.5 ≤ W2 / W1 ≤ 10.0, and more preferably satisfied that 1.6 ≤ W2 / W1 ≤ 7.0. By satisfying such a relationship, a wider width of the hammer head 59 can be ensured. Therefore, even if the length H of the hammer head 59 is relatively short as described above (less than 30% of L), the mass effect by the hammer head 59 can be sufficiently exerted. Thus, by satisfying the relationship of 1.5 ≤ W2 / W1 ≤ 10.0, the overall length L of the vibrating arm 5 can be suppressed, and the miniaturization of the vibration element 2 can be achieved.

[0045] In this way, in the vibrating arm 5, by satisfying the relationship of 0.012 < H / L < 0.3 and the relationship of 1.5 ≤ W2 / W1 ≤ 10.0, due to the synergistic effect of these two relationships, a vibration element 2 with a sufficiently suppressed CI value in miniaturization can be obtained. Note that by setting L to 2 mm or less, preferably 1 mm or less, a small vibration element 2 can be obtained for use in an oscillator mounted on a portable music device or an IC card. Also, by setting W1 to 100 μm or less, preferably 50 μm or less, even within the above range of L, a vibration element 2 that resonates at a low frequency and is used in an oscillation circuit that realizes low power consumption can be obtained.

[0046] In addition, in the case of an adiabatic region, when the vibrating arms extend in the Y-axis direction in a Z-cut quartz plate and flexurally vibrate in the X-axis direction, W1 is preferably 12.8 μm or more, when the vibrating arms extend in the X-axis direction in a Z-cut quartz plate and flexurally vibrate in the Y-axis direction, W1 is preferably 14.4 μm or more, and when the vibrating arms extend in the Y-axis direction in an X-cut quartz plate and flexurally vibrate in the Z-axis direction, W1 is preferably 15.9 μm or more. This ensures that the adiabatic region is created, so that the formation of the grooves 52 and 53 reduces thermoelastic loss and improves the Q value, and at the same time, the CI value is lowered by driving in the region where the grooves 52 and 53 are formed (high electric field efficiency and increased driving area).

[0047] In addition, when the width (length in the X-axis direction) of the banks 511a (main surfaces arranged on either side of the groove 52 along the width direction perpendicular to the longitudinal direction of the vibrating arm) located on both sides of the groove 52 on the main surface 511 in the X-axis direction and the width (length in the X-axis direction) of the banks 512a located on both sides of the groove 53 on the main surface 512 in the X-axis direction are W3 [μm], W3 is set to 6 μm or less. This makes it possible to sufficiently reduce the equivalent series resistance R1 (CI value) while maintaining the Q value of the vibration element 2 relatively high. As a result, it is possible to obtain a vibration element 2 that can exhibit excellent vibration characteristics with low power consumption.

[0048] Here, the reason for setting the width W3 of the banks 511a and 512a to 6 μm or less will be explained based on the results of simulations performed by the inventors. Note that in the following, a simulation using a vibration element 2 formed by patterning a Z-cut quartz crystal plate and having a bending vibration frequency (mechanical bending vibration frequency) f=32.768 kHz is used as a representative, but the inventors have confirmed that there is almost no difference from the simulation results shown below when the bending vibration frequency f is in the range of 32.768 kHz±1 kHz.

[0049] In addition, this simulation uses a vibration element 2 in which a Z-cut quartz plate (rotation angle 0°) is patterned by wet etching. Therefore, the grooves 52 and 53 have a shape in which the crystal planes of the quartz crystal are exposed, as shown in FIG. 7. Note that FIG. 7 shows a cross section corresponding to the cross section of line BB in FIG. 1. Since the etching rate in the -X-axis direction is lower than the etching rate in the +X-axis direction, the side surface in the -X-axis direction has a relatively gentle inclination, and the side surface in the +X-axis direction has an inclination close to vertical.

[0050] The size of the vibrating arms 5 of the vibration element 2 used in this simulation was as follows: total length L 930 μm, thickness T 120 μm, width W1 of the arm portions 51 80 μm, width W2 of the hammer head 59 138 μm, and length H of the hammer head 59 334 μm. In such a vibration element 2, a simulation was performed by changing the width W3 of the bank portions 511a and 512a. The inventors have confirmed that the same tendency as the simulation results shown below is obtained even if the total length L, thickness T, width W1, width W2, and length H are changed. In addition, in this simulation, a vibration element 2 on which the first and second driving electrodes 84, 85 are not formed was used.

[0051] FIG. 8 is a graph showing the relationship between the width W3 of the banks 511a, 512a and the Q value (Q value after F conversion) when the maximum depths t of the grooves 52, 53 are set to 0.208T, 0.292T, 0.375T, 0.458T, and 0.483T, respectively. FIG. 9 is a graph showing the relationship between the width W3 of the banks 511a, 512a and the reciprocal of R1 (1 / R1) when the maximum depths t of the grooves 52, 53 are set to 0.208T, 0.292T, 0.375T, 0.458T, and 0.483T, respectively.

[0052] The graphs shown in FIG. 8 and FIG. 9 are created as follows. First, the Q value is obtained by the finite element method, taking into account only the thermoelastic loss. Since the Q value has frequency dependency, the obtained Q value is converted to the Q value at 32.768 kHz (Q value after F conversion). The graph shown in FIG. 8 is created by plotting the Q value after F conversion on the vertical axis and W3 on the horizontal axis. Furthermore, R1 is calculated based on the Q value after F conversion. Since R1 also has frequency dependency, the obtained R1 is converted to R1 at 32.768 kHz, and the reciprocal of the converted value is plotted on the vertical axis and W3 on the horizontal axis to create the graph shown in FIG. 9. The larger the Q value, the higher the vibration characteristics of the vibration element 2 can be, and the smaller R1 (the larger 1 / R1) is, the lower the power consumption of the vibration element 2 can be.

[0053] The conversion of the Q value into the Q value after F conversion can be calculated as follows using the above formula (1) and the following formula (3). Q = {ρCp / (Cα 2 H)}×[{1+(f / fm0) 2} / (f / fm0)] ...(3) In equation (3), ρ is the mass density of the vibrating arm 5, Cp is the heat capacity of the vibrating arm 5, C is the elastic stiffness constant for expansion and contraction in the longitudinal direction of the vibrating arm 5, α is the thermal expansion coefficient in the longitudinal direction of the vibrating arm 5, H is the absolute temperature, and f is the natural frequency. Note that a is the width (effective width) when the vibrating arm 5 is considered to have a flat plate structure (flat plate shape), but the value of a can also be used to convert to the Q value after F conversion.

[0054] First, the natural frequency of the vibrating arm 5 used in the simulation is F1, the obtained Q value is Q1, and the value of a is obtained using equations (1) and (3) so that f = F1 and Q = Q1. Next, the obtained a is used, and f = 32.768 kHz is set, and the Q value is calculated from equation (3). The Q value obtained in this way becomes the Q value after F conversion. As shown in FIG. 8, the Q value is maximum when the width W3 of the banks 511a, 512a is 7 μm, regardless of the depth of the grooves 52, 53. On the other hand, as shown in FIG. 9, R1 tends to decrease as the width W3 of the banks 511a, 512a decreases. The vibration element is usually designed so that the Q value is as large as possible, that is, so that the width W3 of the banks 511a, 512a is about 7 μm. However, this does not allow the power consumption of the vibration element 2 to be sufficiently low.

[0055] Therefore, in the present invention, the design value of the width W3 of the banks 511a, 512a is not set to the value usually adopted (7 μm at which the Q value is maximized), but rather, a value that makes R1 smaller (6 μm or less) is adopted preferentially, even if it means sacrificing the Q value to some extent. This makes it possible to sufficiently lower the equivalent series resistance R1 (CI value) while maintaining the Q value of the vibration element 2 relatively high. As a result, it is possible to obtain a vibration element 2 that can exhibit excellent vibration characteristics with low power consumption.

[0056] The width W3 of the banks 511a, 512a may be 6 μm or less, but is preferably 0.1 μm to 6 μm, more preferably 0.5 μm to 4 μm, and even more preferably 1 μm to 3 μm. By setting the width W3 in such a range, the R1 (CI value) of the vibration element 2 can be made smaller, and the vibration element 2 can be driven with lower power consumption. Note that it is difficult to form the banks 511a, 512a having a width W3 smaller than the above lower limit, or it requires highly accurate processing technology, resulting in high costs.

[0057] It is also preferable that the thickness T of the vibrating arm 5 (arm portion 51) and the maximum depth t of the grooves 52 and 53 satisfy the relationship 0.458T≦t≦0.483T, and the width W3 of the banks 511a and 512a and η expressed by 2t / T satisfy the relationship -36.000η+39.020≦W3[μm]≦26.000η-15.320 (where 0.916≦η≦0.966). This makes it possible to obtain a vibrating element 2 that exhibits better vibration characteristics.

[0058] In particular, the depth of the grooves 52, 53, i.e., η, is preferably as large as possible, specifically, it is preferably 0.6 or more, more preferably 0.75 or more, and even more preferably 0.9 or more. This allows the formation area of ​​the first and second driving electrodes 84, 85 to be increased, so that R1 (CI value) of the vibration element 2 can be made smaller, and it is possible to obtain a vibration element 2 that operates with lower power consumption.

[0059] Furthermore, since η satisfies the relationship 2t / T, when η is constant, the larger the thickness T of the vibrating arm 5 (quartz substrate 3) is, the larger t can be. This allows the formation area of ​​the first and second driving electrodes 84, 85 to be larger, and R1 of the vibration element 2 to be further reduced. Specifically, the thickness T of the vibrating arm 5 (quartz substrate 3) is preferably 50 μm or more, more preferably 110 μm or more, and even more preferably 160 μm or more. The upper limit of the thickness T of the vibrating arm 5 is not particularly limited, but is preferably 300 μm or less. When the thickness T of the vibrating arm 5 exceeds the upper limit, the shape asymmetry of the vibration element 2 tends to increase, depending on the processing conditions (wet etching conditions) of the quartz substrate 3.

[0060] A support arm 71 is provided between the pair of vibrating arms 5, 6 (arm portions 51, 61) as described above, extending from the base portion 4 (main body portion 41) along the center line C1 (Y-axis direction). The support arm 71 has a substantially rectangular shape when viewed in the XY plane, and the vibrating element 2 is fixed to the package 9 by the support arm 71 via a conductive adhesive 11 as shown in FIGS. 1 and 2, but is not particularly limited and may be fixed to the package 9 via a metal such as Au. With this configuration, vibration leakage from the vibrating element 2 can be more effectively reduced.

[0061] Moreover, the support arm 71 has a constriction 711 in which the length (width) along the X-axis direction is reduced near the boundary with the base 4. This allows the resonance frequency of the X common mode in which the vibrating arms 5 and 6 flexurally oscillate in the same direction in the XY plane to be separated from the resonance frequency of the main mode in which the vibrating arms 5 and 6 flexurally oscillate so as to move away from and towards each other. As a result, when the vibration element 2 flexurally oscillates in the main mode, the vibration mode generated in the X common mode is less likely to overlap with the main mode, making it difficult for so-called coupled vibration to occur, and vibration leakage can be reduced.

[0062] Such a vibration element 2 can be obtained by processing a quartz substrate by, for example, a wet etching method such as alkaline wet etching, or a dry etching method such as laser beam etching or reactive gas etching, but is particularly preferably obtained by processing by a wet etching method. By using the wet etching method, the quartz substrate can be processed with high accuracy using a simple device.

[0063] (package) The package 9 has a box-shaped base 91 having a recess 911 that opens to the top, and a plate-shaped lid 92 that is joined to the base 91 so as to close the opening of the recess 911. Such a package 9 has a storage space that is formed by closing the recess 911 with the lid 92, and the vibration element 2 is stored in this storage space in an airtight manner. The vibration element 2 is fixed to the bottom surface of the recess 911 by the support arm 71 via a conductive adhesive 11 made of, for example, an epoxy-based or acrylic-based resin mixed with a conductive filler. The inside of the storage space may be in a reduced pressure (preferably vacuum) state, or may be filled with an inert gas such as nitrogen, helium, argon, etc. This improves the vibration characteristics of the vibration element 2.

[0064] The material of the base 91 is not particularly limited, but various ceramics such as aluminum oxide can be used. The material of the lid 92 is not particularly limited, but it is preferable that the material has a linear expansion coefficient similar to that of the material of the base 91. For example, when the material of the base 91 is the above-mentioned ceramic, it is preferable that the material is an alloy such as Kovar. The bonding between the base 91 and the lid 92 is not particularly limited, and they may be bonded via an adhesive or by seam welding, for example.

[0065] Furthermore, connection terminals 951, 961 are formed on the bottom surface of the recess 911 of the base 91. Although not shown, the first driving electrode 84 of the vibration element 2 is drawn out to the middle of the Y-axis direction of the support arm 71, and the conductive adhesive 11 is electrically connected to the connection terminal 951 at that portion. Similarly, although not shown, the second driving electrode 85 of the vibration element 2 is drawn out to the middle of the Y-axis direction of the support arm 71, and the conductive adhesive 11 is electrically connected to the connection terminal 961 at that portion. In addition, the connection terminal 951 is electrically connected to an external terminal 953 formed on the bottom surface of the base 91 via a through electrode 952 that penetrates the base 91, and the connection terminal 961 is electrically connected to an external terminal 963 formed on the bottom surface of the base 91 via a through electrode 962 that penetrates the base 91.

[0066] The configuration of the connection terminals 951, 961, the through electrodes 952, 962, and the external terminals 953, 963 is not particularly limited as long as they are conductive, but may be formed, for example, of a metal coating in which a metallized layer (base layer) such as Cr (chromium), W (tungsten) is laminated with coatings such as Ni (nickel), Au (gold), Ag (silver), Cu (copper), etc.

[0067] <Second embodiment> Next, a second embodiment of the vibrator of the present invention will be described. FIG. 10 is a plan view of a vibration element included in a vibrator according to a second embodiment of the present invention. The vibrator of the second embodiment will be described below, focusing on the differences from the first embodiment described above, and a description of the similarities will be omitted. The vibrator of the second embodiment is similar to that of the first embodiment described above, except for the configuration of the vibrating element, and the same reference numerals are used to designate the same configuration as in the first embodiment described above.

[0068] 10, the base 4A of the vibration element 2A has a main body 41, a reduced width portion 42 provided on the base end (second end) side of the main body 41, and a reduced width portion 43 provided between the vibrating arms 5, 6 on the tip (first end) side of the main body 41. The vibration element 2A is fixed to the package 9 at the main body 41 via conductive adhesives 11, 11. For this reason, the support arm 71 is omitted.

[0069] The width (length along the X-axis direction) of the narrowed width portion 43 gradually decreases along the center line C1 between the vibrating arms 5 and 6 as it moves away from the center of the base 4 (main body portion 41), and the contour (edge) thereof is arch-shaped (circular arc-shaped). Such narrowed width portion 43 has a function similar to that of the narrowed width portion 42. In this embodiment, the conductive adhesives 11, 11 are arranged along the center line C1, but may be arranged along a direction perpendicular to the center line C1 (X-axis direction).

[0070] The second embodiment can also achieve the same effects as the first embodiment. In particular, according to the second embodiment, the support arm 71 can be omitted, so that the length (width) of the vibration element 2A along the X-axis direction can be reduced. Note that the base 4 may not have the reduced width portion 42 and may only have the reduced width portion 43, or may not have the reduced width portion 43 and may only have the reduced width portion 42.

[0071] <Third embodiment> Next, a third embodiment of the vibrator of the present invention will be described. FIG. 11 is a plan view of a vibrator according to a third embodiment of the present invention, and FIG. 12 is a cross-sectional view taken along line CC in FIG. The vibrator of the third embodiment will be described below, focusing on the differences from the first embodiment described above, and a description of the similarities will be omitted. The vibrator of the third embodiment is similar to that of the first embodiment described above, except for the configuration of the support portion and the configuration of the package. Note that the same reference numerals are used to designate the same components as those of the first embodiment described above.

[0072] 11, the support portion of the vibration element 2B includes a frame 72 having a substantially square outer shape that surrounds the base 4, the vibrating arms 5 and 6, and the support arm 71B, and the tip end portion (the end portion opposite the base 4) of the support arm 71B is connected to the frame 72. The frame 72 is a portion that is joined to the package 9B. 12, the package 9B has a box-shaped base 91B having a recess 911B opening to the top and a box-shaped lid 92B having a recess 921B opening to the bottom, and the vibration element 2B is fixed to the package 9B by sandwiching and joining a frame 72 to the outer periphery of the base 91B and the outer periphery of the lid 92B. Also, a connection terminal 961 (951) provided on the bottom surface of the recess 911B of the base 91B and a predetermined portion of the vibration element 2B are connected by a wire 12 made of, for example, gold or the like. The third embodiment can also achieve the same effects as the first embodiment. In particular, according to the third embodiment, the vibration element 2B is fixed to the package 9B via the frame 72, and therefore the fixing can be performed with high precision. Therefore, the size of the vibration element 2B can be increased, and as a result, the R1 can be made smaller.

[0073] <Fourth embodiment> Next, a fourth embodiment of the vibrator of the present invention will be described. FIG. 13 is a plan view of a vibration element included in a vibrator according to a fourth embodiment of the present invention. The vibrator of the fourth embodiment will be described below, focusing on the differences from the first to third embodiments described above, and a description of the similarities will be omitted. The vibrator of the fourth embodiment is similar to that of the third embodiment described above, except that the configuration of the support portion is different. Note that the same reference numerals are used to designate the same components as those of the third embodiment described above.

[0074] 13, the support portion of the vibration element 2C is provided with a support arm 73 extending along the center line C1 at the base end (opposite the pair of vibration arms 5 and 6) of the base 4C instead of the support arm 71B. The support arm 73 is connected to a frame 72. The base 4C has the same configuration as the base 4A of the second embodiment. The fourth embodiment can also achieve the same effects as the first embodiment. In particular, according to the fourth embodiment, the vibration element 2C is fixed to the package 9 via the frame 72, and this fixing can be performed with high precision. Therefore, the size of the vibration element 2C can be increased, and as a result, the R1 can be made smaller. Furthermore, according to the fourth embodiment, the support arm 71B can be omitted, and therefore the length (width) of the vibration element 2C along the X-axis direction can be reduced. In addition, the support arm 73 may be omitted and the base 4C may be directly connected to the frame body 72, or the frame body 72 may be omitted and the vibration element 2C may be fixed to the package 9 using the conductive adhesive 11 via the support arm 73.

[0075] 2. Oscillator Next, an oscillator to which the vibration element of the present invention is applied (oscillator of the present invention) will be described. FIG. 14 is a cross-sectional view showing a preferred embodiment of an oscillator of the present invention. 14 includes a vibrator 1 and an IC chip 8 for driving a vibration element 2. The following description of the oscillator 10 will focus on the differences from the vibrator described above, and will omit a description of similar points.

[0076] 14, the package 9 has a box-shaped base 91 having a recess 911, and a plate-shaped lid 92 that closes the opening of the recess 911. The recess 911 of the base 91 has a first recess 911a that opens to the top surface of the base 91, a second recess 911b that opens to the bottom surface of the first recess 911a, and a third recess 911c that opens to the bottom surface of the second recess 911b.

[0077] Connection terminals 95 and 96 are formed on the bottom surface of the first recess 911a. Furthermore, an IC chip 8 is disposed on the bottom surface of the third recess 911c. The IC chip 8 has an oscillation circuit for controlling the driving of the vibration element 2. When the vibration element 2 is driven by the IC chip 8, a signal of a predetermined frequency can be extracted. Further, a plurality of internal terminals 93 electrically connected to the IC chip 8 via wires are formed on the bottom surface of the second recess 911b. The plurality of internal terminals 93 include a terminal electrically connected to an external terminal 94 formed on the bottom surface of the package 9 via vias (not shown) formed in the base 91, a terminal electrically connected to a connection terminal 95 via vias and wires (not shown), and a terminal electrically connected to a connection terminal 96 via vias and wires (not shown). In the configuration of Figure 14, a configuration has been described in which the IC chip 8 is arranged within the storage space, but the arrangement of the IC chip 8 is not particularly limited and may be, for example, arranged outside the package 9 (on the bottom surface of the base 91).

[0078] 3.Electronic equipment Next, an electronic device to which the vibration element of the present invention is applied (electronic device of the present invention) will be described. 15 is a perspective view showing the configuration of a mobile (or notebook) personal computer to which an electronic device having the vibration element of the present invention is applied. In this figure, the personal computer 1100 is composed of a main body 1104 having a keyboard 1102 and a display unit 1106 having a display unit 2000, and the display unit 1106 is rotatably supported on the main body 1104 via a hinge structure. Such a personal computer 1100 has built-in vibration elements 2 (2A to 2C) that function as a filter, a resonator, a reference clock, etc.

[0079] 16 is a perspective view showing the configuration of a mobile phone (including PHS) to which an electronic device equipped with the vibration element of the present invention is applied. In this figure, a mobile phone 1200 has a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206, and a display unit 2000 is disposed between the operation buttons 1202 and the earpiece 1204. Such a mobile phone 1200 has a built-in vibration element 2 (2A to 2C) that functions as a filter, a resonator, or the like.

[0080] Fig. 17 is a perspective view showing the configuration of a digital still camera to which an electronic device equipped with the vibration element of the present invention is applied. This figure also shows a simplified view of the connection to external devices. Here, while a normal camera exposes a silver halide photographic film to the light image of a subject, the digital still camera 1300 photoelectrically converts the light image of a subject using an imaging element such as a CCD (Charge Coupled Device) to generate an imaging signal (image signal).

[0081] A display unit 2000 is provided on the back of a case (body) 1302 of the digital still camera 1300, and is configured to display an image based on an image signal captured by a CCD, and the display unit 2000 functions as a finder that displays an object as an electronic image. A light receiving unit 1304 including an optical lens (image capturing optical system) and a CCD is provided on the front side (rear side in the figure) of the case 1302.

[0082] When the photographer checks the subject image displayed on the display unit 2000 and presses the shutter button 1306, the image signal of the CCD at that time is transferred and stored in the memory 1308. In addition, in this digital still camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side of the case 1302. As shown in the figure, the video signal output terminal 1312 is connected to a television monitor 1430, and the input / output terminal 1314 for data communication is connected to a personal computer 1440, as necessary. Furthermore, the image signal stored in the memory 1308 is configured to be output to the television monitor 1430 or the personal computer 1440 by a predetermined operation. Such a digital still camera 1300 has a built-in vibration element 2 (2A to 2C) that functions as a filter, a resonator, etc.

[0083] In addition to the personal computer (mobile personal computer) of FIG. 15, the mobile phone of FIG. 16, and the digital still camera of FIG. 17, electronic devices equipped with the vibration element of the present invention can be applied to, for example, inkjet ejection devices (e.g., inkjet printers), laptop personal computers, televisions, video cameras, video tape recorders, car navigation devices, pagers, electronic organizers (including those with communication functions), electronic dictionaries, calculators, electronic game devices, word processors, workstations, videophones, security television monitors, electronic binoculars, POS terminals, medical equipment (e.g., electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasound diagnostic equipment, electronic endoscopes), fish finders, various measuring instruments, instruments (e.g., instruments for vehicles, aircraft, and ships), flight simulators, and the like.

[0084] 4. Mobile Next, a moving body to which the vibration element of the present invention is applied (moving body of the present invention) will be described. 18 is a perspective view that shows a schematic diagram of an automobile as an example of a moving body of the present invention. An automobile 1500 is equipped with a vibration element 2. The vibration element 2 (2A to 2C) can be widely applied to electronic control units (ECUs) such as keyless entry, immobilizers, car navigation systems, car air conditioners, antilock braking systems (ABS), airbags, tire pressure monitoring systems (TPMS), engine controls, battery monitors for hybrid and electric automobiles, and vehicle attitude control systems.

[0085] The vibration element, vibrator, oscillator, electronic device, and moving body of the present invention have been described above based on the illustrated embodiments, but the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration having a similar function. In addition, any other configuration may be added to the present invention. In addition, each embodiment may be appropriately combined. [Explanation of symbols]

[0086] 1, 1B... vibrator 10... oscillator 11... conductive adhesive 12... wire 2, 2A, 2B, 2C... vibrating element 3... quartz substrate 4, 4A, 4C... base 41... main body 42, 43... contracted width portion 5... vibrating arm 51... arm 511, 512... main surface 511a, 512a... bank portion 513, 514... side surface 52, 53... groove 59... hammer head 6... vibrating arm 61... arm 611, 612... main surface 613, 614... side surface 62, 63... groove 69... hammer head 71, 71B, 73... support arm 711... waist portion 72... frame 8... IC chip 84, 85... driving electrode 9... package 91, 91B... base 911, 911B, 921B...recess 911a...first recess 911b...second recess 911c...third recess 92, 92B...lid 93...internal terminal 94...external terminal 95, 96...connection terminal 951, 961...connection terminal 952, 962...through electrode 953, 963...external terminal 1100...personal computer 1102...keyboard 1104...main body 1106...display unit 1200...mobile phone 1202...operation button 1204...earpiece 1206...mouthpiece 1300...digital still camera 1302...case 1304...light receiving unit 1306...shutter button 1308...memory 1312...video signal output terminal 1314...input / output terminal 1430...television monitor 1440...Personal computer 1500...Automobile 2000...Display unit L...Total length H...Hammer head length W1, W2, W3...Width t...Depth T...Thickness C1...Center line

Claims

1. A base and The electrodes extend from the base in a first direction and are aligned in a second direction perpendicular to the first direction. a first vibrating arm and a second vibrating arm, a first vibrating arm extending from the base along the first direction and disposed between the first vibrating arm and the second vibrating arm; A support arm disposed Including, The first vibrating arm and the second vibrating arm each have The arm and a base portion of the arm portion and a length of the base portion along the second direction that is longer than the arm portion; The wide section has a large a first surface that is aligned along the first direction and the second direction and has a front-back relationship; and The second side, The first surface and the second surface are connected to one end side of the arm portion in the second direction. a first side surface extending from the other end of the arm portion in the second direction; a second side surface connecting the first surface and the second surface; The first surface has an opening, is provided along the first direction, and has a thickness perpendicular to the first surface. a first groove portion having a bottom and a depth along a direction; a second groove portion having a bottom, the second groove portion being provided along the first direction and having a depth along the thickness direction; Including, The first surface between the first side surface and the first groove portion is called a first bank portion, and the second side surface and The first surface between the first groove portion and the second bank portion is a second bank portion, and the second surface between the first side surface and the second groove portion is a second bank portion. a third bank portion, the second surface between the second side surface and the second groove portion being a fourth bank portion; In a cross section of the arm portion taken along the second direction, The first groove portion has a first inner surface extending from the first bank portion and a second inner surface extending from the second bank portion. a second inner surface, the first inner surface and the second inner surface include portions inclined toward each other, The depth of the first groove portion is from the first surface to an intersection point between the first inner surface and the second inner surface. is the distance, The second groove portion has a third inner surface extending from the third bank portion and a fourth inner surface extending from the fourth bank portion. and a fourth inner surface, the third inner surface and the fourth inner surface include portions inclined toward each other, The depth of the second groove portion is from the second surface to an intersection point between the third inner surface and the fourth inner surface. is the distance, The first bank portion, the second bank portion, the third bank portion, and the fourth bank portion a length along the second direction of the The length of the arm portion along the second direction is W1, and the length of the wide portion along the second direction is W2. When the length is W2, A vibration element characterized by satisfying the relationship: 1.6≦W2 / W1≦7.

0.

2. In claim 1, The support arm is a fixing part attached to the package; Between the fixing portion and the base portion, a portion in the second direction is provided that is longer than a portion where the fixing portion is disposed. and a narrowed portion having a small length.

3. In claim 1, The support arm has a length along the first direction smaller than that of the arm portion of the vibration element.

4. In claim 1, The length of the arm portion along the second direction is 12.8 μm or more and 100 μm or less. Moving element.

5. In claim 1, The arm portion has a length in the second direction between the arm portion and the wide portion that gradually increases toward the wide portion. A vibration element including a tapered portion having a tapered shape.

6. The vibration element according to claim 1 , a package in which the vibration element is housed; A vibrator comprising:

7. The vibration element according to claim 1 , An oscillator circuit; 13. An oscillator comprising:

Images