Vibrating pieces, vibrating devices, and oscillators

Abstract

This invention provides a vibrating element made from a quartz SC-cut substrate, which reduces G sensitivity. [Solution] The vibrating piece 1 is made of an SC-cut quartz plate and comprises a substrate 2 having a first outer edge 21 that intersects with respect to a first direction. The substrate 2 has a first slit 31 between the main region 28 and the first fixing part 4a, and a second slit 32 provided in either the main region 28 or the second fixing part 4b, opening to the front and back surfaces of the substrate 2 and the first outer edge 21. When the length of the substrate including the excitation electrode is Lx, the length of the first slit 31 is L1, and the length of the second slit 32 is L2, L1 / Lx and L2 / Lx are set to a predetermined range.

Description

Technical Field

[0001] The present invention relates to a vibrating piece, a vibration device, and an oscillator.

Background Art

[0002] For example, Patent Document 1 discloses a piezoelectric vibrator having a piezoelectric plate provided with an excitation electrode film on the upper surface. The piezoelectric vibrator has a connection portion connected to a container by a conductive adhesive. The connection portion is provided at a distance from the excitation electrode film to the farthest part. The connection portion is formed by providing a slit in the piezoelectric plate. Generally, due to the difference in the thermal expansion coefficients of the container and the piezoelectric plate and the shrinkage generated when the conductive adhesive cures, deformation stress and strain occur. In the piezoelectric vibrator described in Patent Document 1, it is prevented that the deformation stress and strain affect the excitation electrode film. On the other hand, in the market, there is a demand for a vibration device with low G sensitivity.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, the G sensitivity of the piezoelectric vibrator is not considered.

Means for Solving the Problems

[0005] The vibrating piece according to the application example of the present invention is composed of an SC-cut crystal plate, and has a substrate having a first outer edge and a second outer edge that intersect the first direction, and a third outer edge and a fourth outer edge that are along the first direction, and an excitation electrode provided at the central portion of the substrate in a plan view. When the region where the excitation electrode is disposed and the region located between the excitation electrode and the first outer edge are taken as the main regions, the substrate has a first slit between the main region and the third outer edge, and a second slit between the main region and the fourth outer edge. The first slit and the second slit open to the front and back surfaces of the substrate and the first outer edge. Let the length in the first direction from the first outer edge to the second outer edge be Lx, the length in the first direction from the first outer edge to the end on the second outer edge side of the first slit be L1, and the length in the first direction from the first outer edge to the end on the second outer edge side of the second slit be L2. Then, L1 / Lx and L2 / Lx satisfy any one of the following formulas (1) to (5). 0.00 < L1 / Lx < 0.20 and 0.110 ≤ L2 / Lx ≤ 0.550 × L1 / Lx + 0.860 ··· (1) 0.20 ≤ L1 / Lx < 0.60 and 0.110 ≤ L2 / Lx ≤ 0.970 ··· (2) 0.60 ≤ L1 / Lx < 0.77 and -0.297 × L1 / Lx + 0.288 ≤ L2 / Lx ≤ 0.970 ··· (3) 0.77 ≤ L1 / Lx < 0.97 and -0.297 × L1 / Lx + 0.288 ≤ L2 / Lx ≤ -0.300 × L1 / Lx + 0.451 ··· (4) 0.77 ≤ L1 / Lx < 0.97 and 0.250 × L1 / Lx + 0.128 ≤ L2 / Lx ≤ -0.400 × L1 / Lx + 0.988 ··· (5)

[0006] The vibrating piece according to an application example of the present invention comprises a substrate made of an SC-cut quartz plate, having a first outer edge and a second outer edge intersecting with a first direction, and a third outer edge and a fourth outer edge aligned with the first direction, and an excitation electrode provided in the center of the substrate in a plan view, wherein the substrate has a first slit between the main region and the third outer edge, and a second slit between the main region and the fourth outer edge, with the region located between the excitation electrode and the first outer edge being the main region, and the first slit The first slit and the second slit open on the front and back surfaces and the first outer edge of the substrate, and when the length in the first direction from the first outer edge to the second outer edge is Lx, the length in the first direction from the first outer edge to the end of the first slit on the second outer edge side is L1, and the length in the first direction from the first outer edge to the end of the second slit on the second outer edge side is L2, then L1 / Lx and L2 / Lx satisfy any of the following equations (6) to (14). 0.06 ≤ L1 / Lx < 0.11 and -2.000 × L1 / Lx + 0.700 ≤ L2 / Lx ≤ 1.800 × L1 / Lx + 0.472 ... (6) 0.11 ≤ L1 / Lx ≤ 0.16 and 2.000 × L1 / Lx + 0.260 ≤ L2 / Lx ≤ -1.800 × L1 / Lx + 0.868...(7) 0.43 ≤ L1 / Lx < 0.46 and -1.556 × L1 / Lx + 1.259 ≤ L2 / Lx ≤ 9.000 × L1 / Lx - 3.280 ... (8) 0.46 ≤ L1 / Lx < 0.52 and -1.556 × L1 / Lx + 1.259 ≤ L2 / Lx ≤ 1.833 × L1 / Lx + 0.017 ···(9) 0.52 ≤ L1 / Lx < 0.60 and -0.375 × L1 / Lx + 0.645 ≤ L2 / Lx ≤ 0.970 ···(10) 0.60 ≤ L1 / Lx < 0.69 and 0.071 × L1 / Lx + 0.377 ≤ L2 / Lx ≤ 0.970 ···(11) 0.69 ≤ L1 / Lx < 0.74 and 0.071 × L1 / Lx + 0.377 ≤ L2 / Lx ≤ -0.800 × L1 / Lx + 1.212 ···(12) 0.69 ≤ L1 / Lx < 0.74 and 2.600 × L1 / Lx - 0.954 ≤ L2 / Lx ≤ 0.970 ···(13) 0.74 ≤ L1 / Lx ≤ 0.84 and 1.100 × L1 / Lx - 0.384 ≤ L2 / Lx ≤ -0.800 × L1 / Lx + 1.212 ···(14)

[0007] A vibration device according to an application example of the present invention comprises a vibrating piece and a base that supports the vibrating piece.

[0008] An oscillator according to an application example of the present invention comprises a vibrating element, an oscillation circuit electrically connected to the vibrating element, and a base in which the vibrating element and the oscillation circuit are housed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic plan view showing the configuration of the vibration device according to the first embodiment. [Figure 2] This is a schematic cross-sectional view of the line A1-A1 in Figure 1. [Figure 3A] This diagram illustrates the cutting angle of the vibrating piece. [Figure 3B] This diagram illustrates the cutting angle of the vibrating piece. [Figure 4] This is a plan view illustrating the in-plane rotation angle of the vibrating element. [Figure 5] This is a plan view showing the configuration of the vibrating element according to the first embodiment. [Figure 6] This figure shows the G sensitivity of the vibrating element for L1 / Lx and L2 / Lx. [Figure 7] This is a diagram illustrating region C in Figure 6. [Figure 8] This is a diagram illustrating region B in Figure 6. [Figure 9] This is a cross-sectional view illustrating the forces acting on the vibrating piece. [Figure 10] This is a cross-sectional view illustrating the forces acting on the vibrating piece. [Figure 11] This is a plan view showing the configuration of the vibrating element according to the second embodiment. [Figure 12]It is a plan view showing the configuration of the oscillator according to the third embodiment. [Figure 13] It is a schematic cross-sectional view taken along line A2 - A2 in FIG. 12.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In each of the following figures, the scales of each layer and each member are made different from the actual ones in order to make each layer and each member recognizable.

[0011] Also, for convenience of explanation, in FIGS. 1, 2, 12, and 13, the x-axis, y-axis, and z-axis are illustrated as three mutually orthogonal axes. Also, the direction along the x-axis is referred to as the "x-axis direction", the direction along the y-axis is referred to as the "y-axis direction", and the direction along the z-axis is referred to as the "z-axis direction". Also, the tip side of the arrow in each axis direction is also referred to as the "+ side", and the base end side is referred to as the "- side". Also, the plane parallel to the x-axis and y-axis is also referred to as the "xy plane". Also, the plan view when viewed from the +z direction is simply referred to as the "plan view".

[0012] Also, for convenience of explanation, in FIGS. 3B, 4, 5, 9 to 11, the X'-axis, Y"-axis, and Z'-axis are illustrated as three mutually orthogonal axes, and the tip side of the illustrated arrow is the "+ side" and the base end side is the "- side". Also, in the following description, the direction parallel to the X'-axis is referred to as the "X'-axis direction", the direction parallel to the Y"-axis is referred to as the "Y"-axis direction", and the direction parallel to the Z'-axis is referred to as the "Z'-axis direction". Further, the surface facing the Y"-axis direction will be described as the main surface. Also, the X'-axis corresponds to the x-axis, and the +X' direction is the -x direction. The Z'-axis corresponds to the y-axis, and the +Z' direction is the +y direction. The Y"-axis corresponds to the z-axis, and the +Y" direction is the +z direction. Therefore, the plan view when viewed from the +Y" direction is simply referred to as the "plan view".

[0013] <First Embodiment> A vibration device 100 according to the first embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a schematic plan view showing the configuration of the vibration device 100 according to the first embodiment. Figure 2 is a schematic cross-sectional view taken along line A1-A1 in Figure 1. Note that Figure 1 shows the device with the cover 90 removed.

[0014] The vibration device 100 is a surface-mount component in which a vibrating piece 1 is packaged. The vibration device 100 comprises a base 80, a vibrating piece 1, and a cover 90. The base 80 is a flat plate-shaped member that supports the vibrating piece 1, and the cover 90 is a box-shaped member with a recess 91 formed therein. The base 80 and the cover 90 are joined together to form a package 70. The vibrating piece 1 is housed in the internal space S of the package 70.

[0015] The base 80 has two faces 81 and 82 that are in a front-back relationship in the z-axis direction and are parallel to the xy-plane. The base 80 is approximately rectangular in plan view. The base 80 has two external terminals 83 on the -z side face 81. The base 80 has a pair of electrode pads 84 on the +z side face 82. The pair of electrode pads 84 includes a first electrode pad 85 and a second electrode pad 86. The first electrode pad 85 is electrically connected to one of the external terminals 83. The second electrode pad 86 is electrically connected to the other external terminal 83. The first electrode pad 85 and the second electrode pad 86 are aligned along the y-axis direction. The constituent material of the base 80 is silicon, but is not particularly limited and may be glass or ceramic, for example.

[0016] The lid 90 is box-shaped, with a substantially rectangular shape in plan view and a recess 91 opening in the -z direction. The opening 92 of the recess 91 of the lid 90 is joined to the base 80 via a joining member 93, and the recess 91 together with the base 80 partitions the internal space S that houses the vibrating piece 1. The joining of the lid 90 and the base 80 may be direct joining without using the joining member 93. Furthermore, the internal space S is under reduced pressure, preferably closer to a vacuum. This reduces viscous resistance and improves the oscillation characteristics of the vibrating piece 1. The constituent material of the lid 90 is silicon, but is not particularly limited, and may be, for example, glass or ceramic.

[0017] The vibrating element 1 comprises a substrate 2, a pair of excitation electrodes 3, and a first slit 31 and a second slit 32.

[0018] The substrate 2 is a plate-like structure formed from quartz, parallel to the xy plane, and is an SC-cut quartz plate as described later. The substrate 2 has a first outer edge 21 and a second outer edge 22 along the y-axis direction, and a third outer edge 23 and a fourth outer edge 24 along the x-axis direction. The x-axis direction corresponds to the first direction. The substrate 2 is approximately rectangular. In the x-axis direction, the first outer edge 21 is located on the -x side, and the second outer edge 22 is located on the +x side. In the y-axis direction, the third outer edge 23 is located on the +y side, and the fourth outer edge 24 is located on the -y side.

[0019] The substrate 2 has a first surface 12 and a second surface 13 that are in a front-back relationship in the z-axis direction. The first surface 12 is the -z side and faces the base 80. The second surface 13 is the +z side and faces the cover 90.

[0020] Here, the crystal axes of substrate 2 will be explained using Figures 3A and 3B. Figures 3A and 3B illustrate the cutting angles of substrate 2. The quartz material used for substrate 2 has mutually orthogonal crystal axes X, Y, and Z, as shown in Figure 3A. The X axis is called the electrical axis, the Y axis the mechanical axis, and the Z axis the optical axis. Note that the X, Y, and Z axes are different from the x, y, and z axes in Figures 1, 2, 12, and 13. The axes obtained by rotating the X and Y axes counterclockwise by a predetermined angle of approximately 22° around the Z axis are the X' and Y' axes. Then, as shown in Figure 3B, the axes obtained by rotating the Y' and Z axes counterclockwise by a predetermined angle of approximately 34° around the X' axis are the Y'' axis and Z' axis. Substrate 2 is cut along the X'Z' plane, which is parallel to the X' and Z' axes. The cut substrate 2 has a plane perpendicular to the Y'' axis. In this way, an SC-cut quartz plate is obtained. Furthermore, the SC-cut quartz plate is what is known as a double-rotated Y-cut quartz plate.

[0021] Substrate 2 has orthogonal crystal axes X', Y'' and Z', with the thickness direction being the Y'' axis direction. In substrate 2, the main surface is the plane that is orthogonal to the Y'' axis and includes the X' and Z' axes. In substrate 2, thickness-sliding vibrations are excited as the main vibration on the main surface, and it has excellent stress sensitivity characteristics and thermal shock resistance characteristics.

[0022] The in-plane rotation angle Ψ of the vibrating piece 1 in this embodiment will be explained using Figure 4. Figure 4 is a plan view illustrating the in-plane rotation angle Ψ of the vibrating piece 1. The in-plane rotation angle Ψ is the angle formed between the X' axis and a virtual line 50 that passes through the center of the substrate 2 and is parallel to the third outer edge 23 and the fourth outer edge 24, in a plan view. Specifically, the in-plane rotation angle Ψ is such that, when viewed from the -Y'' direction, the virtual line 50 rotates counterclockwise with respect to the X' axis.

[0023] In Figures 1, 2, 5, 9, and 10, the in-plane rotation angle Ψ of the vibrating piece 1 is 0°.

[0024] Figure 5 is a plan view showing the configuration of the vibrating piece 1 according to the first embodiment. A pair of excitation electrodes 3 are provided in the center of the substrate 2. The pair of excitation electrodes 3 includes a first excitation electrode 3a located on the first surface 12 and a second excitation electrode 3b located on the second surface 13. In a plan view, the first excitation electrode 3a and the second excitation electrode 3b overlap each other.

[0025] In a plan view, the region where the excitation electrode 3 is located and the region located between the excitation electrode 3 and the first outer edge 21 correspond to the main region 28. The substrate 2 has a first slit 31 between the main region 28 and the third outer edge 23. The substrate 2 has a second slit 32 between the main region 28 and the fourth outer edge 24. The first slit 31 and the second slit 32 extend along the X' axis and open into the front and back surfaces of the substrate 2 and the first outer edge 21. That is, the first slit 31 and the second slit 32 penetrate the substrate 2 in the thickness direction.

[0026] In substrate 2, the region between the first slit 31 and the third outer edge 23 is the first arm portion 35. The first arm portion 35 is located on the +Z' side relative to the main region 28. The end of the first slit 31 on the second outer edge 22 side is a closed first crotch portion 33. The region between the first crotch portion 33 and the second outer edge 22 is the first shoulder portion 37. The first shoulder portion 37 connects the main region 28 and the first arm portion 35.

[0027] The first arm 35 has a tip portion 40 on the +X' side. The tip portion 40 is located on the +X' side of the first outer edge 21 in the X' axis direction. That is, the tip portion 40 is located on the +X' side of the imaginary line 51 along the first outer edge 21.

[0028] In substrate 2, the region between the second slit 32 and the fourth outer edge 24 is the second arm portion 36. The second arm portion 36 is located on the -Z' side relative to the main region 28. The end of the second slit 32 on the second outer edge 22 side is the closed second crotch portion 34. The region between the second crotch portion 34 and the second outer edge 22 is the second shoulder portion 38. The second shoulder portion 38 connects the main region 28 and the second arm portion 36.

[0029] The second arm 36 has a tip 41 on the +X' side. The tip 41 is located on the +X' side of the first outer edge 21 in the X' axis direction. That is, the tip 41 is located on the +X' side of the imaginary line 51.

[0030] The vibrating piece 1 has a pair of fixed parts 4. The pair of fixed parts 4 are positioned on the first surface 12 and fixed to the base 80 (see Figures 1 and 2). The pair of fixed parts 4 include a first fixed part 4a electrically connected to the first excitation electrode 3a and a second fixed part 4b electrically connected to the second excitation electrode 3b.

[0031] The first fixing portion 4a is positioned at the tip of the first arm portion 35 in the X' axis direction. That is, the position where the first fixing portion 4a is provided corresponds to the first corner portion 25 where the imaginary line 51 and the third outer edge 23 intersect. The first fixing portion 4a is provided at a position facing the main region 28 via the first slit 31. That is, the first slit 31 is provided between the main region 28 and the first fixing portion 4a.

[0032] The second fixing portion 4b is positioned at the tip of the second arm portion 36 in the X' axis direction. That is, the position where the second fixing portion 4b is provided corresponds to the second corner portion 26 where the imaginary line 51 and the fourth outer edge 24 intersect. The second fixing portion 4b is provided at a position facing the main region 28 via the second slit 32. That is, the second slit 32 is provided between the main region 28 and the second fixing portion 4b.

[0033] The first fixing part 4a and the second fixing part 4b are aligned in the Z' axis direction. That is, the vibrating piece 1 is fixed to the base 80 at one end in the X' axis direction. The vibrating piece 1 is in a so-called cantilevered support state.

[0034] The substrate 2 has lead wires 14 and 15. The first fixed part 4a is electrically connected to the first excitation electrode 3a by lead wire 14. The second fixed part 4b is electrically connected to the second excitation electrode 3b by lead wire 15. The lead wires 14 are arranged on the first shoulder portion 37 and the first arm portion 35 on the first surface 12. The lead wires 15 are arranged on the second shoulder portion 38 and the second arm portion 36 on the second surface 13.

[0035] The first fixing part 4a and the second fixing part 4b are joined to the first electrode pad 85 and the second electrode pad 86 by a conductive bonding member 16 (see Figures 1 and 2). The fixing part 4 is a connecting electrode that connects to the electrode pad 84. In this way, the vibrating piece 1 is supported by the base 80. When a voltage is supplied from the external terminal 83 (see Figure 2), the pair of excitation electrodes 3 apply a voltage to the substrate 2, thereby generating vibration in the vibrating piece 1. The material of the bonding member 16 is not particularly limited and may be Ag paste or Au bump.

[0036] Let Lx be the length in the X' axis direction from the first outer edge 21 to the second outer edge 22. Let L1 be the length in the X' axis direction from the first outer edge 21 to the end of the first slit 31 on the second outer edge 22 side. Let L2 be the length in the X' axis direction from the first outer edge 21 to the end of the second slit 32 on the second outer edge 22 side. In this case, L1 / Lx is the dimensionless length of the first slit 31, and L2 / Lx is the dimensionless length of the second slit 32.

[0037] Figure 6 shows the G sensitivity Γ for lengths L1 / Lx and L2 / Lx. Figure 6 shows the simulation results for vibrating piece 1 with an in-plane rotation angle Ψ of 0° and for vibrating piece 1 with an in-plane rotation angle Ψ of 180°. The horizontal axis represents length L1 / Lx and the vertical axis represents length L2 / Lx, and the G sensitivity Γ is represented as contour lines. Note that the G sensitivity Γ is the square root of the sum of the squares of the G sensitivity in the X' axis direction, the Y'' axis direction, and the Z' axis direction.

[0038] In FIG. 6, regions A to D are regions partitioned by contour lines. In region A, the G sensitivity Γ is 0.2 ppb / G or less. In region B, the G sensitivity Γ is greater than 0.2 ppb / G and 0.6 ppb / G or less. In region C, the G sensitivity Γ is greater than 0.6 ppb / G and 1.0 ppb / G or less. In region D, the G sensitivity Γ is greater than 1.0 ppb / G and 1.4 ppb / G or less.

[0039] The ranges of the lengths L1 / Lx and L2 / Lx when the G sensitivity Γ is 1.0 ppb / G or less will be described using FIG. 7. This range corresponds to regions A, region B, and region C. FIG. 7 is FIG. 6 with auxiliary lines added. Among the auxiliary lines, the boundary line BL1 consists of a plurality of straight line portions including the straight line portions Ls1 to Ls5. The boundary line BL1 forms a polygon that touches the inside of region C.

[0040] The region surrounded by the boundary line BL1 is further divided into regions C1 to C4 according to the range of the length L1 / Lx. The length L1 / Lx of region C1 is greater than 0.00 and less than 0.20. The length L1 / Lx of region C2 is 0.20 or more and less than 0.60, and the length L1 / Lx of region C3 is 0.60 or more and less than 0.77. The length L1 / Lx of region C4 is 0.77 or more and less than 0.97.

[0041] The range of region C1 is represented by the following formula (1). 0.00 < L1 / Lx < 0.20 and 0.110 ≤ L2 / Lx ≤ 0.550 × L1 / Lx + 0.860 ··· (1) Here, 0.550 × L1 / Lx + 0.860 in equation (1) represents the linear portion Ls1. When the horizontal axis of Figure 7 is the x' axis and the vertical axis is the y' axis, the linear portion Ls1 is a part of the straight line represented by the linear function y' = ax' + b. In this case, 0.550 corresponds to the slope a, and 0.860 corresponds to the intercept b. Note that the slope a is the increase in y' for every 1 increase in x'. The intercept b is y' when x' is 0. Note that the x' axis and y' axis are different from the x' axis and y' axis in Figures 1, 2, 12, and 13. Also, the x' axis and y' axis are different from the X' axis and Y'' axis in Figures 3B, 4, 5, 9 to 11.

[0042] The linear section Ls1 is inclined with respect to the horizontal axis, i.e., the x' axis, and the vertical axis, i.e., the y' axis, in Figure 7. The linear sections Ls2 to Ls5 are also inclined with respect to the x' and y' axes, and are therefore represented in the same way as the linear section Ls1, using a slope a and an intercept b.

[0043] The extent of region C2 is expressed by the following equation (2). 0.20 ≤ L1 / Lx < 0.60 and 0.110 ≤ L2 / Lx ≤ 0.970 ···(2) The range of region C3 is expressed by the following equation (3). 0.60 ≤ L1 / Lx < 0.77 and -0.297 × L1 / Lx + 0.288 ≤ L2 / Lx ≤ 0.970 ···(3) The extent of region C4 is expressed by equations (4) and (5). 0.77 ≤ L1 / Lx < 0.97 and -0.297 × L1 / Lx + 0.288 ≤ L2 / Lx ≤ -0.300 × L1 / Lx + 0.451 ···(4) 0.77 ≤ L1 / Lx < 0.97 and 0.250 × L1 / Lx + 0.128 ≤ L2 / Lx ≤ -0.400 × L1 / Lx + 0.988 ···(5)

[0044] Thus, by having lengths L1 / Lx and L2 / Lx satisfy any of equations (1) to (5), the G sensitivity Γ of the vibrating piece 1 can be reduced to 1.0 ppb / G or less.

[0045] Furthermore, the ranges of lengths L1 / Lx and L2 / Lx when the G sensitivity Γ is 0.6 ppb / G or less will be explained using Figure 8. This range corresponds to regions A and B. Figure 8 is Figure 6 with auxiliary lines added. The auxiliary lines include boundary lines BL2 and BL3. Region B includes regions B1 and B2. Boundary line BL2 consists of straight sections La1 to La4. Boundary line BL2 forms a polygon tangent to the inside of region B1. Boundary line BL3 consists of multiple straight sections including straight sections La5 to La12. Boundary line BL3 forms a polygon tangent to the inside of region B2.

[0046] The region enclosed by boundary line BL2 is further divided into regions B11 and B12 depending on the range of L1 / Lx. Similarly, the region enclosed by boundary line BL3 is further divided into regions B21 to B26 depending on the range of L1 / Lx. The linear sections La1 to La12 are inclined with respect to the horizontal axis (x' axis) and vertical axis (y' axis) of Figure 8, and are represented using the slope a and intercept b, similar to the linear sections Ls1 to Ls5 mentioned above.

[0047] The extent of region B11 is expressed by the following equation (6). 0.06 ≤ L1 / Lx < 0.11 and -2.000 × L1 / Lx + 0.700 ≤ L2 / Lx ≤ 1.800 × L1 / Lx + 0.472 ... (6) The extent of region B12 is expressed by the following equation (7). 0.11 ≤ L1 / Lx ≤ 0.16 and 2.000 × L1 / Lx + 0.260 ≤ L2 / Lx ≤ -1.800 × L1 / Lx + 0.868...(7) The extent of region B21 is expressed by the following equation (8). 0.43 ≤ L1 / Lx < 0.46 and -1.556 × L1 / Lx + 1.259 ≤ L2 / Lx ≤ 9.000 × L1 / Lx - 3.280 ... (8) The extent of region B22 is expressed by the following equation (9). 0.46 ≤ L1 / Lx < 0.52 and -1.556 × L1 / Lx + 1.259 ≤ L2 / Lx ≤ 1.833 × L1 / Lx + 0.017 ···(9) The extent of region B23 is expressed by the following equation (10). 0.52 ≤ L1 / Lx < 0.60 and -0.375 × L1 / Lx + 0.645 ≤ L2 / Lx ≤ 0.970 ···(10) The extent of region B24 is expressed by the following equation (11). 0.60 ≤ L1 / Lx < 0.69 and 0.071 × L1 / Lx + 0.377 ≤ L2 / Lx ≤ 0.970 ···(11) The extent of region B25 is expressed by equations (12) and (13). 0.69 ≤ L1 / Lx < 0.74 and 0.071 × L1 / Lx + 0.377 ≤ L2 / Lx ≤ -0.800 × L1 / Lx + 1.212 ···(12) 0.69 ≤ L1 / Lx < 0.74 and 2.600 × L1 / Lx - 0.954 ≤ L2 / Lx ≤ 0.970 ···(13) The extent of region B26 is expressed by the following equation (14). 0.74 ≤ L1 / Lx ≤ 0.84 and 1.100 × L1 / Lx - 0.384 ≤ L2 / Lx ≤ -0.800 × L1 / Lx + 1.212 ···(14)

[0048] Thus, by having lengths L1 / Lx and L2 / Lx satisfy any of equations (6) to (14), the G sensitivity Γ of the vibrating piece 1 can be reduced to 0.6 ppb / G or less.

[0049] One of the factors in which lengths L1 / Lx and L2 / Lx affect the G sensitivity Γ will be explained using Figures 9 and 10 for comparison. Unlike the vibrating piece 1 in this embodiment, the vibrating piece 10 shown in Figure 9 does not have the first slit 31 and the second slit 32. Figure 9 is a cross-sectional view illustrating the forces acting on the vibrating piece 10. Figure 10 is a cross-sectional view illustrating the forces acting on the vibrating piece 1 in this embodiment. In Figures 9 and 10, the +Y” direction is vertically downward.

[0050] In Figure 9, the +X' end of the vibrating piece 10 is fixed to the base 80. On the other hand, the -X' end is not fixed to the base 80 and is therefore in a so-called free end state. The -X' end is subjected to a force F1 that attempts to deform it in the +Y'' direction due to gravity.

[0051] In this state, if the vibrating piece 10 is subjected to acceleration such as vibration or gravitational acceleration, deformation is likely to occur. When the vibrating piece 10 deforms, its frequency fluctuates. In other words, in such a vibrating piece 10, the G sensitivity Γ is not sufficiently suppressed.

[0052] As shown in Figure 10, in the vibrating piece 1, the end on the -X' side is subjected to a force F1 that attempts to deform it in the +Y'' direction due to gravity. The vibrating piece 1 has a first slit 31 and a second slit 32 that are aligned with the X' axis direction and open to the +X' side. Due to the presence of the first slit 31 and the second slit 32, a force F2 is generated in the vibrating piece 1 that attempts to deform it in the +Y'' direction due to gravity, starting from the first groin portion 33 of the first slit 31 and the second groin portion 34 of the second slit 32. The end on the +X' side is the first outer edge 21, and the end on the -X' side is the second outer edge 22. In this way, the vibrating piece 1, subjected to forces F1 and F2, becomes less susceptible to deformation even when subjected to acceleration such as vibration. Therefore, the G sensitivity Γ of the vibrating piece 1 is kept low. Thus, even when subjected to acceleration, the frequency fluctuation of the vibrating piece 1 is small.

[0053] The G sensitivity Γ of the vibrating piece 1 changes depending on the balance between forces F1 and F2. It is more preferable that the magnitudes of forces F1 and F2 are approximately the same. The magnitude of force F2 can be adjusted by the positions of the first and second hip portions 33 and 34. If the positions of the first and second hip portions 33 and 34 are on the -X' side, force F2 is large, and if the positions of the first and second hip portions 33 and 34 are on the +X' side, force F2 is small. In other words, the magnitude of force F2 depends on the length of the first slit 31 in the X' axis direction and the length of the second slit 32 in the X' axis direction. Therefore, the G sensitivity Γ of the vibrating piece 1 can be suppressed by adjusting the lengths of the first and second slits 31 and 32.

[0054] Returning to Figure 5, it is preferable that the joining member 16 that joins the first fixing portion 4a and the first electrode pad 85 be positioned on the +X' side of the dashed line 51 in a plan view. This allows the length of the first arm portion 35 in the X' axis direction to be increased.

[0055] Furthermore, it is preferable that the joining member 16 that connects the second fixing portion 4b and the second electrode pad 86 be positioned on the +X' side of the dashed line 51 in a plan view. This allows the length of the second arm portion 36 in the X' axis direction to be increased.

[0056] As the length of the first arm 35 or the second arm 36 increases, the distance from the fixing part 4 to the excitation electrode 3 also increases. With this configuration, the strain generated in the vibration device 100 can be absorbed by the first arm 35 or the second arm 36. The strain generated in the vibration device 100 includes, for example, thermal strain caused by the difference in thermal expansion coefficients between the base 80 and the substrate 2 when the ambient temperature of the vibration device 100 changes, and strain caused by the deformation of the joining member 16 over time. In this way, the frequency change of the vibration device 100 can be reduced.

[0057] Lengths L1, L2, and Lx can be measured using a measuring microscope, for example, as specified in the Japanese Industrial Standard JIS B7153:1995. If the end face of substrate 2, viewed from the Y'' axis, is inclined with respect to the Y'' axis, measure the outermost edge of substrate 2.

[0058] Although the substrate 2 has been described as being flat, its shape in the thickness direction is not particularly limited to this. For example, the region where the excitation electrode 3 is provided may be a forward mesa or an inverted mesa. Alternatively, it may be convex or beveled. Furthermore, in these cases, one surface may be flat and the other surface may be concave or convex.

[0059] Furthermore, although it has been explained that the base 80 is a flat plate-shaped member and the lid 90 is a box-shaped member with a recess 91, the design is not limited to these configurations. For example, the base 80 may be replaced with a box-shaped base having a recess, and the lid 90 may be replaced with a lid that is a flat plate-shaped member. Alternatively, the box-shaped base may be made of ceramic, and the flat plate-shaped lid may be made of metal.

[0060] Furthermore, the shape of the substrate 2 is not limited to a rectangle; for example, it may be square.

[0061] Furthermore, the vibration device 100 is not limited to having a joining member 16 between the fixed part 4 and the electrode pad 84. For example, the fixed part 4 and the electrode pad 84 may be joined by direct metal-to-metal bonding.

[0062] Furthermore, the joining member 16 that connects the fixing part 4 and the electrode pad 84 is not limited to being positioned on the +X' side of the imaginary line 51 in a plan view. For example, the joining member 16 may be positioned on the -X' side of the imaginary line 51 in a plan view, or it may be positioned on the line of the imaginary line 51.

[0063] Furthermore, the tip portions 40 and 41 are not limited to being located on the +X' side of the imaginary line 51 in the X' axis direction. For example, the tip portions 40 and 41 may be located on the line of the imaginary line 51.

[0064] <Second Embodiment> The vibrating piece 1a according to the second embodiment will be described with reference to Figure 11. Figure 11 is a plan view showing the configuration of the vibrating piece 1a according to the second embodiment.

[0065] The vibrating piece 1a of the second embodiment includes a substrate 2a, a pair of excitation electrodes 3, a first fixed portion 4a, a second fixed portion 4b, a first slit 31, and a second slit 32. The vibrating piece 1a is the same as the vibrating piece 1 of the first embodiment except that the positions of the tip portions 40a and 41a are different.

[0066] The region of the substrate 2a between the first slit 31 and the third outer edge 23 is the first arm portion 35a. The first arm portion 35a is located on the +Z' side relative to the main region 28. The region of the substrate 2a between the second slit 32 and the fourth outer edge 24 is the second arm portion 36a. The second arm portion 36a is located on the -Z' side relative to the main region 28.

[0067] The first arm portion 35a has a tip portion 40a on the +X' side. The tip portion 40a is located on the -X' side of the first outer edge 21 in the X' axis direction. That is, the tip portion 40a is located on the -X' side of the imaginary line 51. In other words, the end of the third outer edge 23 on the first outer edge 21 side is located on the second outer edge 22 side of the first outer edge 21 in the X' axis direction.

[0068] The second arm 36a has a tip 41a on the +X' side. The tip 41a is located on the -X' side of the first outer edge 21 in the X' axis direction. That is, the tip 41a is located on the -X' side of the imaginary line 51. In other words, the end of the fourth outer edge 24 on the first outer edge 21 side is located on the second outer edge 22 side of the first outer edge 21 in the X' axis direction.

[0069] This configuration allows for a smaller vibrating element 1a. Therefore, a compact vibrating device 100 can be provided. Furthermore, the design flexibility regarding the arrangement of the electrode pads 84 on the base 80 can be improved.

[0070] As described above, the position of the first hip portion 33 in the X' axis direction and the position of the second hip portion 34 in the X' axis direction affect the G sensitivity Γ. Therefore, the G sensitivity Γ for lengths L1 / Lx and L2 / Lx are as shown in Figures 6 to 8. Thus, even with a vibrating piece 1a having this configuration, the G sensitivity Γ can be reduced.

[0071] The vibrating piece 1a includes those in which either the position of the tip portion 40a or the position of the tip portion 41a differs from that of the vibrating piece 1 of the first embodiment. That is, for example, the tip portion 40a may be located -X' side of the first outer edge 21 in the X' axis direction, and the tip portion 41a may be located +X' side of the first outer edge 21 in the X' axis direction. Alternatively, the tip portion 40a may be located +X' side of the first outer edge 21 in the X' axis direction, and the tip portion 41a may be located -X' side of the first outer edge 21 in the X' axis direction.

[0072] Furthermore, while Figure 11 shows an example where length L1 is longer than length L2, the example is not limited to this. Length L1 may be shorter than length L2, or lengths L1 and L2 may be the same length.

[0073] <Third Embodiment> Regarding the oscillator 200 according to the third embodiment, a crystal oscillator equipped with the aforementioned vibrating element 1 will be used as an example and explained with reference to Figures 12 and 13. Figure 12 is a schematic plan view showing the configuration of the oscillator 200. Figure 13 is a schematic cross-sectional view taken along line A2-A2 in Figure 12. Note that in Figure 12, the cover 202 is removed for the convenience of explaining the internal configuration of the oscillator 200.

[0074] The oscillator 200 includes a base 201, a cover 202, a vibrating element 1, and an oscillation circuit 203.

[0075] The structure of the oscillator 200 is substantially the same as that of the vibration device 100 of the first embodiment, except that the oscillation circuit 203 is provided on the base 201. The oscillation circuit 203 is electrically connected to the excitation electrode 3 provided on the vibrating piece 1, and can excite the vibrating piece 1.

[0076] The oscillator 200 of this embodiment uses an SC-cut quartz plate, and therefore exhibits excellent stress sensitivity characteristics and thermal shock resistance characteristics. Furthermore, because the oscillator 200 is equipped with a vibrating element 1, the G sensitivity Γ can be reduced. Note that the oscillator 200 may be equipped with a vibrating element 1a instead of vibrating element 1.

[0077] The above description is based on embodiments of the vibrating pieces 1, 1a, the vibrating device 100, and the oscillator 200. However, this embodiment is not limited thereto, and the configuration of each part can be replaced with any configuration having a similar function. In addition, other arbitrary components may be added to this embodiment. Furthermore, each embodiment may be combined as appropriate. [Explanation of symbols]

[0078] 1,1a...Vibrating piece, 2,2a...Substrate, 3...Excitation electrode, 3a...First excitation electrode, 3b...Second excitation electrode, 4...Fixed part, 4a...First fixed part, 4b...Second fixed part, 10...Vibrating piece, 12...First surface, 13...Second surface, 14,15...Lead wiring, 16...Jointing member, 21...First outer edge, 22...Second outer edge, 23...Third outer edge, 24...Fourth outer edge, 25...First corner, 26...Second corner, 28...Main region, 31...First slit, 32...Second slit, 33...First hip, 34...Second hip, 35,35a...First arm, 36,36a...Second arm, 37...First shoulder, 38...Second shoulder portion, 40,40a...Tip portion, 41,41a...Tip portion, 50,51...Dummy lines, 70...Package, 80...Base, 81,82...Surface, 83...External terminal, 84...Electrode pad, 85...First electrode pad, 86...Second electrode pad, 90...Lid, 91...Recess, 92...Opening, 93...Jointing member, 100...Vibration device, 200...Oscillator, 201...Base, 202...Lid, 203...Oscillation circuit, A~D...Regions, B1,B2,B11,B12,B21~B26...Regions, C1~C4...Regions, BL1~BL3...Boundary lines, F1,F2...Force

Claims

1. A substrate made of an SC-cut quartz plate, having a first outer edge and a second outer edge that intersect with respect to a first direction, and a third outer edge and a fourth outer edge that are aligned with the first direction, The device comprises an excitation electrode located in the center of the substrate in a plan view, The aforementioned substrate is When the region where the excitation electrode is located and the region located between the excitation electrode and the first outer edge are defined as the main region, there is a first slit between the main region and the third outer edge, and a second slit between the main region and the fourth outer edge, The first slit and the second slit open on the front and back surfaces and the first outer edge of the substrate, Let Lx be the length in the first direction from the first outer edge to the second outer edge. When the length in the first direction from the first outer edge to the end of the first slit on the second outer edge side is L1, and the length in the first direction from the first outer edge to the end of the second slit on the second outer edge side is L2, A vibrating piece characterized in that L1 / Lx and L2 / Lx satisfy any of the following equations (1) to (5). 0.00 < L1 / Lx < 0.20 and 0.110 ≤ L2 / Lx ≤ 0.550 × L1 / Lx + 0.860 ... (1) 0.20 ≤ L1 / Lx < 0.60 and 0.110 ≤ L2 / Lx ≤ 0.970 ... (2) 0.60 ≤ L1 / Lx < 0.77 and -0.297 × L1 / Lx + 0.288 ≤ L2 / Lx ≤ 0.970 ... (3) 0.77 ≤ L1 / Lx < 0.97 and -0.297 × L1 / Lx + 0.288 ≤ L2 / Lx ≤ -0.300 × L1 / Lx + 0.451 ... (4) 0.77 ≤ L1 / Lx < 0.97 and 0.250 × L1 / Lx + 0.128 ≤ L2 / Lx ≤ -0.400 × L1 / Lx + 0.988 ... (5)

2. A substrate made of an SC-cut quartz plate, having a first outer edge and a second outer edge that intersect with respect to a first direction, and a third outer edge and a fourth outer edge that are aligned with the first direction, The device comprises an excitation electrode located in the center of the substrate in a plan view, The aforementioned substrate is When the region located between the excitation electrode and the first outer edge is defined as the main region, there is a first slit between the main region and the third outer edge, and a second slit between the main region and the fourth outer edge, The first slit and the second slit open on the front and back surfaces and the first outer edge of the substrate, Let Lx be the length in the first direction from the first outer edge to the second outer edge. When the length in the first direction from the first outer edge to the end of the first slit on the second outer edge side is L1, and the length in the first direction from the first outer edge to the end of the second slit on the second outer edge side is L2, A vibrating piece characterized in that L1 / Lx and L2 / Lx satisfy any of the following equations (6) to (14). 0.06 ≤ L1 / Lx < 0.11 and -2.000 × L1 / Lx + 0.700 ≤ L2 / Lx ≤ 1.800 × L1 / Lx + 0.472 ... (6) 0.11 ≤ L1 / Lx ≤ 0.16 and 2.000 × L1 / Lx + 0.260 ≤ L2 / Lx ≤ -1.800 × L1 / Lx + 0.868 ... (7) 0.43 ≤ L1 / Lx < 0.46 and -1.556 × L1 / Lx + 1.259 ≤ L2 / Lx ≤ 9.000 × L1 / Lx - 3.280 ... (8) 0.46 ≤ L1 / Lx < 0.52 and -1.556 × L1 / Lx + 1.259 ≤ L2 / Lx ≤ 1.833 × L1 / Lx + 0.017 ... (9) 0.52 ≤ L1 / Lx < 0.60 and -0.375 × L1 / Lx + 0.645 ≤ L2 / Lx ≤ 0.970 ... (10) 0.60 ≤ L1 / Lx < 0.69 and 0.071 × L1 / Lx + 0.377 ≤ L2 / Lx ≤ 0.970 ... (11) 0.69 ≤ L1 / Lx < 0.74 and 0.071 × L1 / Lx + 0.377 ≤ L2 / Lx ≤ -0.800 × L1 / Lx + 1.212 ... (12) 0.69 ≤ L1 / Lx < 0.74 and 2.600 × L1 / Lx - 0.954 ≤ L2 / Lx ≤ 0.970 ... (13) 0.74 ≤ L1 / Lx ≤ 0.84 and 1.100 × L1 / Lx - 0.384 ≤ L2 / Lx ≤ -0.800 × L1 / Lx + 1.212 ... (14)

3. The vibrating piece according to claim 1 or 2, wherein at least one of the end of the third outer edge on the first outer edge side and the end of the fourth outer edge on the first outer edge side is located on the second outer edge side of the first outer edge in the first direction.

4. A vibrating piece according to claim 1 or 2, A vibrating device comprising a base that supports the vibrating piece.

5. A vibrating piece according to claim 1 or 2, An oscillation circuit electrically connected to the vibrating element, An oscillator comprising: a base housing the vibrating element and the oscillation circuit.

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