Vibrating element and oscillator

Abstract

A vibration element and an oscillator capable of high-precision temperature compensation, the oscillator having the vibration element. The vibration element has a quartz substrate having a first vibration portion having a pair of first excitation electrodes, a second vibration portion having a pair of second excitation electrodes, and a third vibration portion having a pair of third excitation electrodes, at least one of the pair of second excitation electrodes being formed on a first inclined surface inclined with respect to two main surfaces of the quartz substrate, and at least one of the pair of third excitation electrodes being formed on a second inclined surface inclined with respect to the two main surfaces and the first inclined surface.

Description

TECHNICAL FIELD

[0001] The present application relates to a vibration element and an oscillator. BACKGROUND

[0002] A temperature compensated crystal oscillator (TCXO: Temperature Compensated Crystal Oscillator) having a temperature detecting element and a temperature compensation circuit is widely used for the purpose of obtaining a stable frequency signal over a wide temperature range. However, in the TCXO, a vibration element composed of quartz and the temperature detecting element are separately constituted, and thus, a detection error occurs between the temperature detected by the temperature detecting element and the temperature of the vibration element, and it is difficult to perform high-precision temperature compensation.

[0003] Therefore, as shown in Patent Document 1, a vibration element in which a first vibration portion for outputting an oscillation signal and a second vibration portion for temperature detection are provided on a common piezoelectric plate is disclosed. Since the two vibration portions are formed on the common piezoelectric plate, heat transfer between the first vibration portion and the second vibration portion can be rapidly performed. Therefore, compared to the case where the vibration element and the temperature detecting element are separately constituted, the detection error between the temperature detected by the second vibration portion for temperature detection and the temperature of the first vibration portion for outputting an oscillation signal is reduced, and higher-precision temperature compensation can be performed.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2013-98841

[0005] However, in the vibration element described in Patent Document 1, the excitation electrode for outputting an oscillation signal and the excitation electrode for temperature detection are formed on the same face of the piezoelectric plate at the same cut angle, and thus, the first vibration portion for outputting an oscillation signal and the second vibration portion for temperature detection have the same frequency-temperature characteristics. There is a problem that the first vibration portion for outputting an oscillation signal is set to a cut angle such that the frequency change with respect to the temperature change is small, and thus, the second vibration portion for temperature detection also becomes a frequency-temperature characteristic in which the frequency change with respect to the temperature change is small, the resolution of the temperature change with respect to the frequency change is low, and accurate temperature detection cannot be achieved. SUMMARY

[0006] The vibration element has a quartz substrate having a first vibration portion, a second vibration portion disposed on one side of the first vibration portion in a first direction, and a third vibration portion disposed on one side of the first vibration portion in the first direction and juxtaposed with the second vibration portion in a second direction perpendicular to the first direction; a pair of first excitation electrodes formed on both main surfaces of the quartz substrate in the first vibration portion; a pair of second excitation electrodes formed in the second vibration portion in a manner of sandwiching the second vibration portion in a thickness direction of the quartz substrate; and a pair of third excitation electrodes formed in the third vibration portion in a manner of sandwiching the third vibration portion in the thickness direction of the quartz substrate, at least one of the second excitation electrodes of the pair of second excitation electrodes being formed on a first inclined surface inclined with respect to the both main surfaces, at least one of the third excitation electrodes of the pair of third excitation electrodes being formed on a second inclined surface inclined with respect to the both main surfaces, the second inclined surface being inclined with respect to the first inclined surface.

[0007] The oscillator has the above-described vibration element; a first oscillation circuit electrically connected to the first excitation electrodes, which outputs a first oscillation signal; a second oscillation circuit electrically connected to the second excitation electrodes, which outputs a second oscillation signal; a third oscillation circuit electrically connected to the third excitation electrodes, which outputs a third oscillation signal; and a control signal output circuit which inputs at least one of the second oscillation signal and the third oscillation signal, and which outputs a control signal for controlling an oscillation frequency of the first oscillation signal on the basis of the input signal. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a plan view showing a vibration element of a first embodiment.

[0009] Figure 2 is a cross-sectional view along the line A-A in Figure 1 .

[0010] Figure 3 is a cross-sectional view along the line B-B in Figure 1 .

[0011] Figure 4 is a diagram showing a cut angle of a quartz substrate.

[0012] Figure 5 is a diagram showing a relationship between a cut angle of a quartz substrate and a frequency-temperature characteristic.

[0013] Figure 6 is a diagram showing an example of a frequency-temperature characteristic of a vibration element.

[0014] Figure 7 is a cross-sectional schematic view showing a manufacturing process of a vibration element.

[0015] Figure 8 This is a cross-sectional schematic diagram showing the manufacturing process of the vibrating element.

[0016] Figure 9 This is a cross-sectional schematic diagram showing the manufacturing process of the vibrating element.

[0017] Figure 10 This is a cross-sectional schematic diagram showing the manufacturing process of the vibrating element.

[0018] Figure 11 This is a cross-sectional schematic diagram showing the manufacturing process of the vibrating element.

[0019] Figure 12 This is a cross-sectional schematic diagram showing the manufacturing process of the vibrating element.

[0020] Figure 13 This is a top view showing the vibrating element of the second embodiment.

[0021] Figure 14 It is along Figure 13 A cross-sectional view of the CC line.

[0022] Figure 15 This is a top view showing the vibrating element of the third embodiment.

[0023] Figure 16 It is along Figure 15 A cross-sectional view of the DD line.

[0024] Figure 17 This is a top view showing the vibrating element of the fourth embodiment.

[0025] Figure 18 It is along Figure 17 A cross-sectional view of the EE line.

[0026] Figure 19 This is a top view showing the vibrating element of the fifth embodiment.

[0027] Figure 20 It is along Figure 19 A cross-sectional view of the FF line in the diagram.

[0028] Figure 21 This is a top view showing the vibrating element of the sixth embodiment.

[0029] Figure 22 It is along Figure 21 A cross-sectional view of the GG line in the image.

[0030] Figure 23 This is a top view showing the vibrating element of the seventh embodiment.

[0031] Figure 24 It is along Figure 23a cross-sectional view taken along the H-H line in FIG. 1.

[0032] Figure 25 is a plan view showing a vibration element of the eighth embodiment.

[0033] Figure 26 is a cross-sectional view taken along the J-J line in FIG. 7. Figure 25

[0034] Figure 27 is a plan view showing an oscillator of the ninth embodiment.

[0035] Figure 28 is a cross-sectional view taken along the K-K line in FIG. 10. Figure 27

[0036] is a block diagram showing a circuit structure of the oscillator of the ninth embodiment. Figure 29

[0037] is a block diagram showing a circuit structure of the oscillator of the tenth embodiment. Figure 30

[0038] is a graph showing an example of a relationship between a difference in frequency variation amount of a vibration element and temperature. Figure 31

[0039] Explanation of Reference Numerals

[0040] 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g: vibration element; 2: quartz substrate; 3: first vibration portion; 4: first excitation electrode; 5: second vibration portion; 6: second excitation electrode; 7: third vibration portion; 8: third excitation electrode; 9: fixed portion; 10, 11, 12: terminal; 13, 14, 15: lead electrode; 16a: first main surface; 16b: second main surface; 17: first inclined surface; 18: second inclined surface; 19: through-hole; 20, 21, 22, 23: thin-walled portion; 25: convex portion; 26, 27: inclined portion; 30, 31, 32, 33: concave portion; 61a: first oscillation circuit; 61b: second oscillation circuit; 61c: third oscillation circuit; 63: control signal output circuit; 64b, 64c: input terminal; 65: output terminal; 66: varicap diode; 67: frequency detection portion; 68: temperature estimation portion; 69: compensation voltage operation portion; 70: addition portion; 90: output selection circuit; 91: selection control portion; 92: output selection portion; 93: temperature sensor; 100: oscillator; X1: first vibration element; X2: second vibration element; X3: third vibration element; θ1, θ2, θ3: angle. DETAILED DESCRIPTION

[0041] 1. First Embodiment

[0042] 1.1. Vibration Element​​

[0043] First, the outline structure of the vibration element 1 of the first embodiment will be described with reference to Figure 1 , Figure 2 and Figure 3 .

[0044] Further, the Y' axis and the Z' axis in the following Figures 1 to 4 and Figures 7 to 26 are axes obtained by rotating the Y axis and the Z axis of the X axis, the Y axis, and the Z axis, which are perpendicular to each other, around the X axis by a predetermined angle. Furthermore, the direction along the X axis is referred to as the "X direction", the direction along the Y' axis is referred to as the "Y' direction", and the direction along the Z' axis is referred to as the "Z' direction". Furthermore, in the present embodiment, the X direction corresponds to the first direction, and the Z' direction corresponds to the second direction.

[0045] As shown in Figure 1 , the vibration element 1 of the present embodiment has a quartz substrate 2 having a first vibration portion 3, a second vibration portion 5, and a third vibration portion 7, a first excitation electrode 4 formed on the first vibration portion 3, a second excitation electrode 6 formed on the second vibration portion 5, a third excitation electrode 8 formed on the third vibration portion 7, terminals 10, 11, 12 formed on a fixed portion 9, a lead electrode 13 electrically connecting the first excitation electrode 4 and the terminal 10, a lead electrode 14 electrically connecting the second excitation electrode 6 and the terminal 11, and a lead electrode 15 electrically connecting the third excitation electrode 8 and the terminal 12.

[0046] The vibration element 1 has a first vibration element X1, a second vibration element X2, and a third vibration element X3. The first vibration element X1 has the first vibration portion 3 on which a pair of the first excitation electrodes 4 is formed. The second vibration element X2 has the second vibration portion 5 on which a pair of the second excitation electrodes 6 is formed. The third vibration element X3 has the third vibration portion 7 on which a pair of the third excitation electrodes 8 is formed. The first vibration element X1, the second vibration element X2, and the third vibration element X3 share the quartz substrate 2, and thus, a configuration in which heat from the outside easily and uniformly transmits is obtained.

[0047] The quartz substrate 2 has the first vibration portion 3, the second vibration portion 5 disposed on one side in the X direction, which is the first direction, of the first vibration portion 3, the third vibration portion 7 disposed on one side in the X direction of the first vibration portion 3 and arranged side by side with the second vibration portion 5 in the Z' direction, which is the second direction, perpendicular to the X direction, and the fixed portion 9 for fixing the quartz substrate 2 to a package or the like not shown. Further, the quartz substrate 2 is a flat plate in which an XZ' surface is a main surface, a first main surface 16a and a second main surface 16b parallel to the first main surface 16a are provided, and the Y' direction is a thickness direction.

[0048] The first vibration portion 3, the second vibration portion 5, and the third vibration portion 7, and the fixed portion 9 are arranged in the X direction, and the fixed portion 9 is arranged at the end portion of the quartz substrate 2 in the X direction, that is, the end portion on the side of the second vibration portion 5 and the third vibration portion 7. That is, the first vibration portion 3 and the fixed portion 9 are arranged apart in a manner of sandwiching the second vibration portion 5 and the third vibration portion 7 therebetween. Therefore, a deformation generated when the quartz substrate 2 is fixed to a package or the like is less likely to be transmitted to the first vibration portion 3.

[0049] As shown in FIG. 1, the first vibration portion 3 has a first main surface 16a of the quartz substrate 2 and a second main surface 16b parallel to the first main surface 16a. On the first main surface 16a and the second main surface 16b of the first vibration portion 3, a pair of first excitation electrodes 4 is formed in a manner of sandwiching the first vibration portion 3 in the thickness direction of the quartz substrate 2. The first excitation electrode 4 on the first main surface 16a side and the first excitation electrode 4 on the second main surface 16b side are arranged to overlap when viewed from the Y' direction. In addition, the first main surface 16a and the second main surface 16b correspond to two main surfaces. Figure 2

[0050] As shown in FIG. 2, the second vibration portion 5 has a first inclined surface 17 of the quartz substrate 2 and the second main surface 16b. On the first inclined surface 17 and the second main surface 16b of the second vibration portion 5, a pair of second excitation electrodes 6 is formed in a manner of sandwiching the second vibration portion 5 in the thickness direction of the quartz substrate 2. The second excitation electrode 6 on the first inclined surface 17 side and the second excitation electrode 6 on the second main surface 16b side are arranged to overlap when viewed from the Y' direction. Figure 3 In addition, the first inclined surface 17 is an inclined surface inclined at a prescribed inclination angle with respect to the first main surface 16a, and in the present embodiment, the first inclined surface 17 is inclined in a manner that the thickness of the second vibration portion 5 becomes thinner as it approaches the second inclined surface 18 of the third vibration portion 7.

[0051] As shown in FIG. 3, the third vibration portion 7 has the second inclined surface 18 of the quartz substrate 2 and the second main surface 16b. On the second inclined surface 18 and the second main surface 16b of the third vibration portion 7, a pair of third excitation electrodes 8 is formed in a manner of sandwiching the third vibration portion 7 in the thickness direction of the quartz substrate 2. The third excitation electrode 8 on the second inclined surface 18 side and the third excitation electrode 8 on the second main surface 16b side are arranged to overlap when viewed from the Y' direction.

[0052] Figure 3 In addition, the second inclined surface 18 is an inclined surface inclined at a prescribed inclination angle with respect to the first main surface 16a, and in the present embodiment, the second inclined surface 18 is inclined in a manner that the thickness of the third vibration portion 7 becomes thinner as it approaches the first inclined surface 17 of the second vibration portion 5.

[0053] In addition, the first inclined surface 17 is an inclined surface inclined at a prescribed inclination angle with respect to the first main surface 16a, and in the present embodiment, the first inclined surface 17 is inclined in a manner that the thickness of the second vibration portion 5 becomes thinner as it approaches the second inclined surface 18 of the third vibration portion 7. ​​

[0054] On the first main surface 16a and the second main surface 16b of the fixed portion 9, a terminal 10 electrically connected to the first excitation electrode 4 formed in the first vibration portion 3 via the lead electrode 13, a terminal 11 electrically connected to the second excitation electrode 6 formed in the second vibration portion 5 via the lead electrode 14, and a terminal 12 electrically connected to the third excitation electrode 8 formed in the third vibration portion 7 via the lead electrode 15 are respectively formed.

[0055] Further, on the first main surface 16a and the second main surface 16b of the fixed portion 9, terminals 10, 11, 12 not connected to the lead electrodes 13, 14, 15 are respectively formed, which are respectively electrically connected to the terminals 10, 11, 12 connected to the lead electrodes 13, 14, 15 via side electrodes not shown.

[0056] The first vibration element X1 is formed with a pair of the first excitation electrodes 4 on both the main surfaces 16a, 16b of the first vibration portion 3, and thus, by applying a voltage to the terminal 10, the first vibration portion 3 can be vibrated.

[0057] The second vibration element X2 is formed with a pair of the second excitation electrodes 6 on the first inclined surface 17 and the second main surface 16b of the second vibration portion 5 in a manner of sandwiching the second vibration portion 5 in the thickness direction of the quartz substrate 2, and thus, by applying a voltage to the terminal 11, the second vibration portion 5 can be vibrated.

[0058] The third vibration element X3 is formed with a pair of the third excitation electrodes 8 on the second inclined surface 18 and the second main surface 16b of the third vibration portion 7 in a manner of sandwiching the third vibration portion 7 in the thickness direction of the quartz substrate 2, and thus, by applying a voltage to the terminal 12, the third vibration portion 7 can be vibrated.

[0059] A through hole 19 is provided between the second vibration portion 5 and the third vibration portion 7. By providing the through hole 19, it is possible to reduce the vibration of the second vibration portion 5 from being transmitted to the third vibration portion 7, and conversely, it is also possible to reduce the vibration of the third vibration portion 7 from being transmitted to the second vibration portion 5.

[0060] In addition, the through hole 19 can be provided with a plurality, or can not be provided with any.

[0061] Next, the cutting angle of the quartz substrate 2 of the present embodiment will be described with reference to Figure 4 to the drawing.

[0062] In addition, the arrow side of the arrow R in Figure 4 is called "positive direction", and the side opposite to the arrow is called "negative direction".

[0063] As shown in Figure 4As shown, the piezoelectric material such as quartz belongs to a trigonal system, and has crystal axes, i.e., an X axis, a Y axis, and a Z axis, which are perpendicular to each other. The X axis, the Y axis, and the Z axis are respectively referred to as an electric axis, a mechanical axis, and an optical axis.

[0064] For example, as the piezoelectric substrate, a flat plate composed of a so-called rotated Y-cut quartz substrate, which is cut from a quartz along a plane obtained by rotating an XZ plane around an X axis by a prescribed angle θ1, is used as the quartz substrate 2. In addition, the angle θ1 is also referred to as a cut angle of the rotated Y-cut quartz substrate.

[0065] In addition, a rotation direction of the XZ plane around the X axis is indicated by an arrow R, and a left-hand rotation when viewed from a positive direction of the X axis as a rotation axis is set to be positive rotation, and a right-hand rotation is set to be negative rotation.

[0066] When a coordinate axis obtained by rotating the Y axis around the X axis by the angle θ1 is set to be a Y' axis, and a coordinate axis obtained by rotating the Z axis around the X axis by the angle θ1 is set to be a Z' axis, the rotated Y-cut quartz substrate can be expressed by perpendicular crystal axes, i.e., the X axis, the Y' axis, and the Z' axis. For the rotated Y-cut quartz substrate, a thickness direction is the Y' direction, an XZ' plane including the X axis and the Z' axis perpendicular to the Y' axis is a main surface, and a thickness shear vibration is excited as a main vibration in the main surface.

[0067] Here, the rotated Y-cut quartz substrate in which the angle θ1 is approximately 35° 15' is referred to as an AT-cut quartz substrate, and has excellent frequency-temperature characteristics. Hereinafter, in the present embodiment, the AT-cut quartz substrate is used as an example of the quartz substrate 2, but is not limited to the AT-cut quartz substrate, and for example, a quartz substrate such as a BT-cut, which excites a thickness shear vibration, can be used. In addition, in a case where the AT-cut quartz substrate is used as the quartz substrate 2, the angle θ1 can be approximately 35° 15', and for example, the angle θ1 can be 35° 17'.

[0068] In the present embodiment, the angle θ1 of the quartz substrate 2 is set to be 35° 15'. Therefore, cut angles of the two main surfaces 16a and 16b of the quartz substrate 2 are the angle θ1, i.e., 35° 15'.

[0069] The first inclined surface 17 of the quartz substrate 2 is inclined by an angle θ2 with the first main surface 16a as a reference. That is, the first inclined surface 17 of the quartz substrate 2 is rotated from the Z' axis around the X axis toward a negative direction, and therefore, a cut angle of the first inclined surface 17 is θ1 - θ2, i.e., 35° 15' - θ2.

[0070] The second inclined surface 18 of the quartz substrate 2 is inclined by an angle θ3 with the first main surface 16a as a reference. That is, the second inclined surface 18 of the quartz substrate 2 is rotated from the Z' axis around the X axis toward a positive direction, and therefore, a cut angle of the second inclined surface 18 is θ1 + θ3, i.e., 35° 15' + θ3.

[0071] In the present embodiment, the cut angle of the first inclined surface 17 is θ1-θ2, and the cut angle of the second inclined surface 18 is θ1+θ3. The cut angles of the two main surfaces 16a, 16b, the cut angle of the first inclined surface 17, and the cut angle of the second inclined surface 18 are different from each other.

[0072] The cut angle of the first inclined surface 17 being different from the cut angle of the second inclined surface 18 can also be said that the second inclined surface 18 is inclined with respect to the first inclined surface 17.

[0073] Next, the relationship between the cut angle of the quartz substrate 2 and the frequency-temperature characteristics will be described with reference to Figure 5 and Figure 6

[0074] In addition, Figure 5 The relationship between the frequency-temperature characteristics and the cut angle is shown at intervals of 2' with the AT-cut quartz substrate having a cut angle of 35° 15' as a reference. For example, in Figure 5 the curve indicated by +10 represents the frequency-temperature characteristics of the rotated Y-cut quartz substrate having a cut angle of 35° 15' +10', i.e., 35° 25'. In this way, by changing the cut angle, the amount of change Δf / f in the frequency with respect to the temperature change can be adjusted.

[0075] Here, in the present embodiment, one of the pair of second excitation electrodes 6 exciting the second vibration portion 5 is provided on the first inclined surface 17, and the other is provided on the second main surface 16b. Therefore, the frequency-temperature characteristics of the second vibration element X2 of the present embodiment become intermediate characteristics between the frequency-temperature characteristics corresponding to the cut angle θ1-θ2=35° 15'-θ2 of the first inclined surface 17 and the frequency-temperature characteristics corresponding to the cut angle θ1=35° 15' of the second main surface 16b. Specifically, the amount of change Δf / f in the frequency with respect to the temperature change of the second vibration element X2 is the amount of change Δf / f in the frequency with respect to the temperature change when the cut angle is ((θ1-θ2)+θ1) / 2=(2θ1-θ2) / 2, i.e., θ1-θ2 / 2=35° 15'-θ2 / 2.

[0076] ​Further, one of the pair of third excitation electrodes 8 exciting the third vibration portion 7 is provided on the second inclined surface 18, and the other is provided on the second main surface 16b. Therefore, the frequency-temperature characteristic of the third vibration element X3 of the present embodiment is a characteristic intermediate between the frequency-temperature characteristic corresponding to the cut angle 35° 15' + θ3 of the second inclined surface 18 and the frequency-temperature characteristic corresponding to the cut angle 35° 15' of the second main surface 16b. Specifically, the amount of change Δf / f in frequency with respect to temperature change of the third vibration element X3 is the amount of change Δf / f in frequency with respect to temperature change when the cut angle is 35° 15' + θ3 / 2.

[0077] In FIG. 6, which shows an example of the frequency-temperature characteristic of the vibration element 1 of the present embodiment, Figure 6 AT1 indicates the frequency-temperature characteristic of the first vibration element X1, AT2 indicates the frequency-temperature characteristic of the second vibration element X2, and AT3 indicates the frequency-temperature characteristic of the third vibration element X3. As shown in FIG. 6, the frequency-temperature characteristics in the first vibration portion 3 of the first vibration element X1, the second vibration portion 5 of the second vibration element X2, and the third vibration portion 7 of the third vibration element X3 are different. Figure 6

[0078] The angle θ1 of the first vibration portion 3 is 35° 15', and since an AT-cut quartz substrate is directly used, the amount of change Δf / f in frequency with respect to temperature change of the first vibration element X1 is small. Therefore, by providing the first vibration element X1 as an oscillation signal output, a relatively stable oscillation signal with respect to temperature change can be obtained.

[0079] The second vibration portion 5 is adjusted so that the amount of change Δf / f in frequency with respect to temperature change is larger than that of the first vibration portion 3 by changing the angle θ2 of the first inclined surface 17, and the third vibration portion 7 is adjusted so that the amount of change Δf / f in frequency with respect to temperature change is larger than that of the first vibration portion 3 by changing the angle θ3 of the second inclined surface 18. The larger amount of change Δf / f in frequency with respect to temperature change of the second vibration element X2 and the third vibration element X3 means that temperature detection with high resolution and high accuracy with respect to the change in frequency with respect to temperature change can be performed. Therefore, by providing the second vibration element X2 and the third vibration element X3 as temperature detection, temperature can be detected with high accuracy.

[0080] ​In this embodiment, when the cutting angle of the two main surfaces 16a and 16b is θ1, the cutting angle of the first inclined surface 17 of the second vibrating part 5 is θ1-θ2, i.e., 35°15′-θ2. The cutting angle of the first inclined surface 17 of the second vibrating part 5 is smaller than the cutting angle θ1 of the two main surfaces 16a and 16b. Furthermore, the cutting angle of the second inclined surface 18 of the third vibrating part 7 is θ1+θ3, i.e., 35°15′+θ3, which is larger than the cutting angle θ1 of the two main surfaces 16a and 16b. By setting the cutting angles of the first inclined surface 17 of the second vibrating part 5 and the second inclined surface 18 of the third vibrating part 7 to be different angles, the frequency-temperature characteristics of the second vibrating element X2 and the third vibrating element X3 used for temperature detection can be made different.

[0081] By making the frequency-temperature characteristics of the second vibration element X2 and the third vibration element X3 for temperature detection different, for example, temperature detection can be performed based on the second vibration element X2 within a temperature range in which the resolution of temperature change relative to frequency change of the second vibration element X2 is higher and the accuracy is higher than that of the third vibration element X3, and temperature detection can be performed based on the third vibration element X3 within a temperature range in which the resolution of temperature change relative to frequency change of the third vibration element X3 is higher and the accuracy is higher than that of the second vibration element X2, thereby achieving higher accuracy temperature detection.

[0082] For example, in Figure 6 Within the temperature range T from -10°C to 60°C, the resolution of temperature change relative to frequency change for the third vibrating element X3 is higher than that for the second vibrating element X2. Therefore, temperature detection can be performed based on the third vibrating element X3. On the other hand, within the temperature range T below -10°C or above 60°C, the resolution of temperature change relative to frequency change for the third vibrating element X3 decreases, and the frequency change of the third vibrating element X3 does not show a monotonically increasing or decreasing trend relative to temperature change. Therefore, within the temperature range T below -10°C or above 60°C, temperature detection can be performed based on the second vibrating element X2, which has a higher resolution of temperature change relative to frequency change than the third vibrating element X3.

[0083] Furthermore, the temperature range for using the second vibration element X2 for temperature detection and the temperature range for using the third vibration element X3 for temperature detection are not limited to the above-mentioned temperature ranges, and can be arbitrarily set according to the frequency-temperature characteristics of the second vibration unit 5 and the third vibration unit 7.

[0084] Further, the first vibration element X1, the second vibration element X2, and the third vibration element X3 are formed on the common quartz substrate 2, and thus heat transfer between the first vibration element X1 and the second vibration element X2, heat transfer between the first vibration element X1 and the third vibration element X3, and heat transfer between the second vibration element X2 and the third vibration element X3 are each promptly performed. Therefore, the temperature of the first vibration element X1 can be promptly and highly accurately detected by the second vibration element X2 and the third vibration element X3 for temperature detection, and thus temperature compensation of the first vibration element X1 can be promptly and highly accurately performed. Further, the temperature difference between the second vibration element X2 and the third vibration element X3 can be reduced.

[0085] In addition, in the present embodiment, the first inclined surface 17 is formed on the first main surface 16a of the quartz substrate 2, but can be formed on the second main surface 16b, or on both of the main surfaces 16a and 16b.

[0086] Further, in the present embodiment, the second inclined surface 18 is formed on the first main surface 16a of the quartz substrate 2, but can be formed on the second main surface 16b, or on both of the main surfaces 16a and 16b.

[0087] Further, in the case where an AT-cut quartz substrate is used as the quartz substrate 2, when the cutting angle of the inclined surface of which the cutting angle is larger among the first inclined surface 17 of the quartz substrate 2 and the second inclined surface 18 of the quartz substrate 2 is θa, and the cutting angle of the other inclined surface is θb, the preferable range of the cutting angle θb is θa-1° or more and θa-20° or less. When the cutting angle θb is θa-1° or more, the difference between the cutting angle of the first inclined surface 17 of the quartz substrate 2 and the cutting angle of the second inclined surface 18 of the quartz substrate 2 is sufficiently large, and thus the frequency-temperature characteristics of the second vibration element X2 and the third vibration element X3 for temperature detection can be made sufficiently different from each other, and accurate temperature detection can be achieved, and thus is preferable. Further, when the cutting angle θb is increased, it is difficult to form the inclined surface, and thus it is preferable that the cutting angle θb is θa-20° or less. In the present embodiment, the cutting angle θ1-θ2 of the first inclined surface 17 corresponds to θb, and the cutting angle θ1+θ3 of the second inclined surface 18 corresponds to θa.

[0088] As described above, the vibration element 1 of this embodiment enables the frequency changes of the second vibration element X2 with the first inclined surface 17 and the third vibration element X3 with the second inclined surface 18 relative to temperature changes to be greater than the frequency changes of the first vibration element X1 relative to temperature changes. Therefore, when the second vibration element X2 and the third vibration element X3 are used for temperature detection, high-resolution and high-precision temperature detection of temperature changes relative to frequency changes can be achieved. The temperature of the first vibration element X1 can be detected with high precision.

[0089] 1.2. Manufacturing method of vibrating element

[0090] Next, refer to Figures 7 to 12 The manufacturing method of the vibrating element 1 will be described.

[0091] The manufacturing method of the vibration element 1 includes a quartz substrate preparation process, a resist coating process, a dry etching process, a monolithization process, and an electrode formation process.

[0092] 1.2.1 Quartz substrate preparation process

[0093] like Figure 7 As shown, considering the mass production capability and manufacturing cost of the vibrating element 1, a large quartz substrate 80 capable of batch manufacturing multiple vibrating elements 1 is prepared. The large quartz substrate 80 is made by cutting quartz raw stone at a predetermined cutting angle θ1 and performing grinding, polishing, and other processes to achieve the desired thickness. In this embodiment, the cutting angle θ1 is 35°15′.

[0094] 1.2.2. Resist Coating Process

[0095] like Figure 8 As shown, resist 82 is applied to the two main surfaces 16a and 16b of the large quartz substrate 80. Here, as a method for applying resist 82 to the first main surface 16a, the following method is used: resist 82 is filled into a mold having recesses corresponding to the shapes of the first inclined surface 17 to be formed of the second excitation electrode 6 and the second inclined surface 18 to be formed of the third excitation electrode 8; the resist 82 filled in the mold is transferred to the first main surface 16a and cured. Resist 82 is not applied to the portion forming the through hole 19.

[0096] 1.2.3. Dry Etching Process

[0097] Next, dry etching is used, such as... Figure 9 As indicated by the middle arrow, dry etching is performed from above the first main surface 16a using a plasma etching apparatus or the like.

[0098] Figure 10 This shows the state after resist 82 has been removed by dry etching.Figure 8 The shape of the resist 82 formed in the inclined surface shape on the first main surface 16a is directly transferred to the large quartz substrate 80 and thinned. The first inclined surface 17 and the second inclined surface 18 are formed on the large quartz substrate 80 in this manner.

[0099] 1.2.4. Singulation Step

[0100] In Figure 10 , since it becomes a state in which a plurality of quartz pieces are joined on the large quartz substrate 80, the large quartz substrate 80 is singulated. In Figure 10 , the large quartz substrate 80 is singulated by cutting or wet etching based on the imaginary line L. In Figure 11 , a quartz substrate 2 after singulation is shown.

[0101] 1.2.5. Electrode Formation Step

[0102] As shown in Figure 12 , on the quartz substrate 2 after singulation, the first excitation electrode 4, the second excitation electrode 6, the third excitation electrode 8, and the like are formed by evaporation or sputtering to form the vibration element 1.

[0103] In addition, regarding the formation of the first inclined surface 17 and the second inclined surface 18, it can also be formed by means other than the above-described method. For example, as a method of forming the resist 82 which is thinned in a part, a method of gradation exposure in which the resist 82 is exposed in conditions in which the light amount distribution is different can also be used.

[0104] Furthermore, it can also be a method in which, before the large quartz substrate 80 is singulated, the first excitation electrode 4, the second excitation electrode 6, the third excitation electrode 8, and the like are formed on the large quartz substrate 80 together, and then singulation is performed to obtain the vibration element 1.

[0105] Furthermore, the first vibration element X1, the second vibration element X2, and the third vibration element X3 are formed on the common quartz substrate 2, and heat transfer between the first vibration element X1, the second vibration element X2, and the third vibration element X3 is performed rapidly, respectively. Furthermore, since the first inclined surface 17 and the second inclined surface 18 can be formed by a manufacturing method which has less load on the quartz substrate 2 such as a dry etching method, a decrease in mechanical strength of the quartz substrate 2, deterioration over time is less likely to occur.

[0106] 2. Second Embodiment

[0107] The outline structure of the vibration element 1a of the second embodiment is described with reference to Figure 13 and Figure 14 . The same reference numerals are assigned to the same structures as those of the first embodiment, and the overlapping description is omitted.

[0108] As shown in Figure 13 and Figure 14 In the quartz substrate 2a of the present embodiment, the first inclined surface 17a provided in the second vibration portion 5a and the second inclined surface 18a provided in the third vibration portion 7a are inclined in a manner that the thicknesses of the second vibration portion 5a and the third vibration portion 7a become thinner as they move away from each other.

[0109] The first inclined surface 17a of the quartz substrate 2a is rotated from the Z' axis around the X axis by a positive rotation angle θ2. That is, when the cutting angle of the two main surfaces 16a, 16b is θ1, the cutting angle of the first inclined surface 17a is θ1+θ2, that is, 35°15' + θ2, which is larger than the cutting angle θ1 of the two main surfaces 16a, 16b. Further, the second inclined surface 18a of the quartz substrate 2a is rotated from the Z' axis around the X axis by a negative rotation angle θ3. That is, the cutting angle of the second inclined surface 18a is θ1-θ3, that is, 35°15' - θ3, which is smaller than the cutting angle θ1 of the two main surfaces 16a, 16b. In this way, the cutting angle of the first inclined surface 17a is θ1+θ2, and the cutting angle of the second inclined surface 18a is θ1-θ3, and the cutting angle of the first inclined surface 17a is different from the cutting angle of the second inclined surface 18a.

[0110] According to the present embodiment, the frequency change amount of the frequency-temperature characteristics of the second vibration element X2a having the second vibration portion 5a and the third vibration element X3a having the third vibration portion 7a is larger than the frequency-temperature characteristics of the first vibration portion 3, and thus, when the second vibration element X2a and the third vibration element X3a are used for temperature detection, temperature detection with high resolution and high accuracy of the change in temperature with respect to the change in frequency can be achieved, and the same effects as the first embodiment can be obtained.

[0111] 3. Third Embodiment

[0112] Referring to Figure 15 and Figure 16 , the outline structure of the vibration element 1b of the third embodiment will be described. The same reference numerals are assigned to the same structures as those of the first embodiment, and the overlapping description will be omitted.

[0113] As shown in Figure 15 and Figure 16 , the quartz substrate 2b of the present embodiment has a surface 17ba parallel to the first inclined surface 17b on the side opposite to the first inclined surface 17b in the second vibration portion 5b, and has a surface 18ba parallel to the second inclined surface 18b on the side opposite to the second inclined surface 18b in the third vibration portion 7b.

[0114] The second vibration portion 5b of the quartz substrate 2b is rotated from the Z' axis around the X axis toward a negative rotation angle θ2. That is, when the cut angle of the two main surfaces 16a, 16b is θ1= 35° 15', the cut angle of the second vibration portion 5b is θ1- θ2, that is, 35° 15'- θ2, which is smaller than the cut angle θ1 of the two main surfaces 16a, 16b. Further, the third vibration portion 7b of the quartz substrate 2b is rotated from the Z' axis around the X axis toward a positive rotation angle θ3. That is, the cut angle of the third vibration portion 7b is θ1+ θ3, that is, 35° 15'+ θ3, which is larger than the cut angle θ1 of the two main surfaces 16a, 16b. In this way, the cut angle of the second vibration portion 5b is θ1- θ2, and the cut angle of the third vibration portion 7b is θ1+ θ3, and the cut angle of the second vibration portion 5b is different from the cut angle of the third vibration portion 7b.

[0115] According to the present embodiment, the following effects can be obtained in addition to the effects of the first embodiment.

[0116] The second vibration portion 5b and the third vibration portion 7b are each formed by inclined surfaces parallel to the front and back surfaces, and thus, compared to a case where the front and back inclined surfaces are not parallel, it is easy to confine the vibration energy of the second vibration portion 5b between the second excitation electrodes 6 and to confine the vibration energy of the third vibration portion 7b between the third excitation electrodes 8. Therefore, the second vibration element X2b and the third vibration element X3b having a small impedance and a high Q value can be obtained.

[0117] 4. Fourth Embodiment

[0118] Reference Figure 17 and Figure 18 The outline structure of the vibration element 1c of the fourth embodiment will be described. The same reference numerals are given to the same structures as those of the first embodiment, and the overlapping description will be omitted.

[0119] As shown in Figure 17 and Figure 18 , the quartz substrate 2c of the present embodiment is formed with a protrusion 25 on each of the two main surfaces 16a, 16b in the first vibration portion 3c. A pair of first excitation electrodes 4 is formed on the first vibration portion 3c having the protrusion 25 in a manner of sandwiching the first vibration portion 3c in the thickness direction of the quartz substrate 2c.

[0120] According to the present embodiment, the following effects can be obtained in addition to the effects of the first embodiment.

[0121] In the first vibration element X1c, the region including the convex portion 25 of the first vibration portion 3c is excited by the first excitation electrode 4, and thus the vibration energy of the first vibration portion 3c is confined in the region including the convex portion 25. This makes it possible to reduce the leakage of vibration to a region other than the region including the convex portion 25, and to stabilize the vibration of the first vibration element X1c. In addition, it is possible to reduce the impedance of the first vibration element X1c, and to increase the Q value. Thus, when such a first vibration element X1c is used in an oscillator, it is possible to realize a high-precision oscillator with a good carrier-to-noise ratio.

[0122] In the present embodiment, the convex portion 25 is formed on each of both main surfaces 16a and 16b in the first vibration portion 3c, but the convex portion 25 can be formed on either one of the main surfaces 16a and 16b in the first vibration portion 3c.

[0123] In the present embodiment, the convex portion 25 is formed in a mesa shape protruding in the Y' direction from both main surfaces 16a and 16b in the first vibration portion 3c, but the convex portion 25 can be formed in a spherical shape.

[0124] 5. Fifth Embodiment

[0125] Reference Figure 19 and Figure 20 The outline structure of the vibration element 1d of the fifth embodiment will be described. The same reference numerals are given to the same structures as those of the first embodiment, and the overlapping description will be omitted.

[0126] As shown in Figure 19 and Figure 20 , the quartz substrate 2d of the present embodiment is formed with inclined portions 26 and 27 on the first main surface 16a in the first vibration portion 3d, which are inclined in such a manner that the thickness of the quartz substrate 2 becomes thinner toward the outer edge side of the quartz substrate 2d from the side of the first excitation electrode 4.

[0127] According to the present embodiment, the following effects can be obtained in addition to the effects of the first embodiment.

[0128] The first vibration element X1d is formed with inclined portions 26 and 27 around the first excitation electrode 4, which are inclined in such a manner that the thickness of the quartz substrate 2 becomes thinner toward the outer edge side of the quartz substrate 2d. Thus, it is possible to confine the vibration energy of the first vibration portion 3d in the vicinity of the first excitation electrode 4, and to reduce the leakage of vibration to the inclined portions 26 and 27. Thus, it is possible to reduce the impedance of the first vibration element X1d, and to increase the Q value. Thus, when such a first vibration element X1d is used in an oscillator, it is possible to realize a high-precision oscillator with a good carrier-to-noise ratio.

[0129] In addition, in the present embodiment, the inclined portions 26, 27 are formed only on the first main surface 16a in the first vibration portion 3d, but the inclined portions 26, 27 can be formed on both the main surfaces 16a, 16b in the first vibration portion 3d.

[0130] 6. Sixth Embodiment

[0131] Referring to Figure 21 and Figure 22 , the outline structure of the vibration element 1e of the sixth embodiment will be described. The same reference numerals are assigned to the same structures as those of the first embodiment, and overlapping descriptions will be omitted.

[0132] As shown in Figure 21 and Figure 22 , the quartz substrate 2f of the present embodiment is provided with a recess 30 that opens toward the second main surface 16b side between the second vibration portion 5 and the third vibration portion 7. That is, as shown in Figure 22 , a thin-walled portion 20 is formed between the second vibration portion 5 and the third vibration portion 7.

[0133] According to the present embodiment, the following effects can be obtained in addition to the effects of the first embodiment.

[0134] By providing the thin-walled portion 20 between the second vibration portion 5 and the third vibration portion 7, it is possible to suppress the vibration of the second vibration portion 5 from affecting the vibration of the third vibration portion 7.

[0135] In addition, the recess 30 can be formed on the first main surface 16a side.

[0136] 7. Seventh Embodiment

[0137] Referring to Figure 23 and Figure 24 , the outline structure of the oscillation element 1f of the seventh embodiment will be described. The same reference numerals are assigned to the same structures as those of the first embodiment, and overlapping descriptions will be omitted.

[0138] As shown in Figure 23 and Figure 24 , the quartz substrate 2f of the present embodiment is provided with a recess 31 that opens toward the second main surface 16b side between the first vibration portion 3 and the second vibration portion 5 and the third vibration portion 7. That is, as shown in Figure 24 , a thin-walled portion 21 is formed between the first vibration portion 3 and the second vibration portion 5 and the third vibration portion 7.

[0139] According to the present embodiment, the following effects can be obtained in addition to the effects of the first embodiment.

[0140] By providing the thin-walled portions 21 between the first vibration portion 3 and the second vibration portion 5 and between the first vibration portion 3 and the third vibration portion 7, it is possible to suppress the vibrations of the first vibration portion 3, the second vibration portion 5, and the third vibration portion 7 from affecting each other.

[0141] In addition, the recess 31 can also be formed on the first main surface 16a side and can also be formed as a hole that penetrates the quartz substrate 2f.

[0142] 8. Eighth Embodiment

[0143] Reference Figure 25 and Figure 26 The outline structure of the vibration element 1g of the eighth embodiment will be described. The same reference numerals are assigned to the same structures as those of the first embodiment, and the overlapping description will be omitted.

[0144] As shown in Figure 25 and Figure 26 , the quartz substrate 2g of the present embodiment is provided with a recess 32 that opens toward the second main surface 16b side between the first vibration portion 3 and the second vibration portion 5 and between the first vibration portion 3 and the third vibration portion 7, and a recess 33 that opens toward the second main surface 16b side between the second vibration portion 5 and the third vibration portion 7. That is, as shown in Figure 26 , thin-walled portions 22 are formed between the first vibration portion 3 and the second vibration portion 5 and between the first vibration portion 3 and the third vibration portion 7, and a thin-walled portion 23 is formed between the second vibration portion 5 and the third vibration portion 7.

[0145] According to the present embodiment, in addition to the effects of the first embodiment, the following effects can also be obtained.

[0146] By providing the thin-walled portions 22, 23 between the first vibration portion 3 and the second vibration portion 5, between the first vibration portion 3 and the third vibration portion 7, and between the second vibration portion 5 and the third vibration portion 7, it is possible to suppress the vibrations of the first vibration portion 3, the second vibration portion 5, and the third vibration portion 7 from affecting each other.

[0147] In addition, the recesses 32, 33 can also be formed on the first main surface 16a side and can also be formed as holes that penetrate the quartz substrate 2g.

[0148] 9. Ninth Embodiment

[0149] Reference Figure 27 and Figure 28 The outline structure of the oscillator 100 of the ninth embodiment will be described. In the oscillator 100 of the ninth embodiment, any one of the above-described vibration elements 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g can be used, and hereinafter, an example in which the vibration element 1 described in the first embodiment is applied will be described.

[0150] As shown in Figure 27 , the oscillator 100 has a vibrator 40 in which the vibration element 1 is built in, an IC chip 60 having an oscillation circuit 61a, 61b, 61c for driving the vibration element 1 and a control signal output circuit 63, a package main body 50 that houses the vibrator 40, the IC chip 60, and a cover member 57 made of glass, ceramic, metal, or the like.

[0151] As shown in Figure 28 , the package main body 50 is formed by laminating the mounting terminal 45, the first substrate 51, the second substrate 52, and the sealing ring 53. Further, the package main body 50 has a chamber 58 that is open upward. In addition, the cover member 57 is joined to the chamber 58 that houses the vibrator 40 and the IC chip 60 by the sealing ring 53, whereby it is hermetically sealed to a reduced pressure environment or an inert gas environment such as nitrogen.

[0152] The mounting terminal 45 is provided on the outer bottom surface of the first substrate 51. Further, the mounting terminal 45 is electrically connected to the connection electrode 43 and the connection terminal 44 provided above the first substrate 51 via a through electrode and an interlayer wiring, not shown.

[0153] The vibrator 40 and the IC chip 60 are housed in the chamber 58 of the package main body 50. The vibrator 40 is fixed to the connection electrode 43 provided above the first substrate 51 by solder or a conductive adhesive. The IC chip 60 is fixed to the upper side of the first substrate 51 by an adhesive or the like. Further, a plurality of connection terminals 44 are provided in the chamber 58. The connection terminal 44 is electrically connected to the connection terminal 46 provided above the IC chip 60 by a bonding wire 56.

[0154] The IC chip 60 has a first oscillation circuit 61a that oscillates the first vibration element Xl and outputs a first oscillation signal, a second oscillation circuit 61b that oscillates the second vibration element X2 and outputs a second oscillation signal, a third oscillation circuit 61c that oscillates the third vibration element X3 and outputs a third oscillation signal, and a control signal output circuit 63 that outputs a control signal for controlling the oscillation frequency of the first oscillation signal based on the second oscillation signal and the third oscillation signal.

[0155] Next, the circuit structure of the oscillator 100 will be described with reference to Figure 29 . In the following description, an example of a TCXO will be described.

[0156] The control signal output circuit 63 is a circuit for outputting the set frequency f0 from the output terminal 65 without depending on an external temperature change of the oscillator 100 or suppressing an influence of the external temperature change. The set frequency f0 is an output frequency obtained when the reference voltage V0 is applied to the first oscillation circuit 61a at the reference temperature To.

[0157] The pair of first excitation electrodes 4 of the first vibration element Xl are electrically connected to the first oscillation circuit 61a via the terminal 10. The pair of second excitation electrodes 6 of the second vibration element X2 are electrically connected to the second oscillation circuit 61b for temperature detection via the terminal 11. The pair of third excitation electrodes 8 of the third vibration element X3 are electrically connected to the third oscillation circuit 61c for temperature detection via the terminal 12.

[0158] As shown in FIG. 1, the first oscillation circuit 61a is connected to the input terminal 64a. The second oscillation circuit 61b is connected to the input terminal 64b. The third oscillation circuit 61c is connected to the input terminal 64c. The output terminal 65 is connected to the control signal output circuit 63. Figure 29 As shown in FIG. 1, the first oscillation circuit 61a is connected to the input terminal 64a. The second oscillation circuit 61b is connected to the input terminal 64b. The third oscillation circuit 61c is connected to the input terminal 64c. The output terminal 65 is connected to the control signal output circuit 63. C (V C = V0- ΔV).

[0159] The output selection circuit 90 has a selection control section 91 and an output selection section 92. The selection control section 91 is electrically connected to the output selection section 92, a temperature sensor 93, and a temperature estimation section 68. The temperature sensor 93 detects an external temperature of the vibration element 1. The selection control section 91 selects a frequency f to be output to the control signal output circuit 63 from among an oscillation frequency f2 as a second oscillation signal output from the second oscillation circuit 61b and an oscillation frequency f3 as a third oscillation signal output from the third oscillation circuit 61c, in accordance with a temperature detected by the temperature sensor 93. Further, the selection control section 91 controls the output selection section 92 in a manner of switching the frequency f as an output signal output from the output selection circuit 90. The output selection section 92 outputs one of the oscillation frequency f2 output from the second oscillation circuit 61b and the oscillation frequency f3 output from the third oscillation circuit 61c as the output signal, i.e., the frequency f, to the control signal output circuit 63 in accordance with the selection of the selection control section 91.

[0160] A reference voltage V 10 a reference voltage V 11The set frequency f0 is output from the output terminal 65. Further, the reference voltage V 10 11 and the control voltage V C are input to the first oscillation circuit 61a, the second oscillation circuit 61b, and the third oscillation circuit 61c, respectively.

[0161] The second vibration element X2 and the third vibration element X3 function as temperature detecting sections. The oscillation frequency f2 output from the second oscillation circuit 61b that drives the second vibration element X2 as a second oscillation signal becomes an output corresponding to the temperature T of the second vibration element X2 according to the frequency-temperature characteristic of the second vibration element X2. Further, the oscillation frequency f3 output from the third oscillation circuit 61c that drives the third vibration element X3 as a third oscillation signal becomes an output corresponding to the temperature T of the third vibration element X3 according to the frequency-temperature characteristic of the third vibration element X3. The temperature T of the second vibration element X2 and the temperature T of the third vibration element X3 can be found in this way.

[0162] The first vibration element X1 is provided on the quartz substrate 2 common to the second vibration element X2 and the third vibration element X3, and the first vibration element X1 is combined with the second vibration element X2 and the third vibration element X3 without a difference in heat transfer time, so the temperature T of the first vibration element X1 can be accurately estimated from the temperature T of the second vibration element X2 and the temperature T of the third vibration element X3.

[0163] The cut angle of the second vibration section 5 is different from the cut angle of the third vibration section 7, so the frequency-temperature characteristic of the second vibration element X2 is different from the frequency-temperature characteristic of the third vibration element X3. Therefore, for example, if the temperature T of the first vibration element X1 is estimated from the temperature T of the second vibration element X2 in a temperature range in which temperature detection with a higher resolution of a change in temperature with respect to a change in frequency and higher accuracy can be achieved for the second vibration element X2, and the temperature T of the first vibration element X1 is estimated from the temperature T of the third vibration element X3 in a temperature range in which temperature detection with a higher resolution of a change in temperature with respect to a change in frequency and higher accuracy can be achieved for the third vibration element X3, the temperature T of the first vibration element X1 can be estimated with higher accuracy.

[0164] The control signal output circuit 63 operates the control voltage V C (V C = V0-ΔV) from the temperature T of the one of the second vibration element X2 and the third vibration element X3 that has a frequency-temperature characteristic with a larger amount of change in frequency, and controls the control voltage V C for outputting the set frequency f0 from the first oscillation circuit 61a as a first oscillation signal. ​

[0165] Specifically, the control signal output circuit 63 has a frequency detection section 67 constituted by, for example, a frequency counter or the like for measuring the frequency f output from the output selection circuit 90, a temperature estimation section 68 for estimating the temperature T from the frequency f measured in the frequency detection section 67, a compensation voltage operation section 69 for operating the compensation voltage ΔV from the temperature T estimated in the temperature estimation section 68, and an addition section 70 for outputting to the first oscillation circuit 61a a control voltage V obtained by subtracting the compensation voltage ΔV operated by the compensation voltage operation section 69 from the reference voltage Vo. C .

[0166] The frequency-temperature characteristics of the second oscillation circuit 61b shown in (1) and the frequency-temperature characteristics of the third oscillation circuit 61c shown in (2) are stored in the temperature estimation section 68.

[0167] In a case where the output selection section 92 selects the oscillation frequency f2 output from the second oscillation circuit 61b as the frequency f to be output to the control signal output circuit 63, the temperature estimation section 68 can estimate the temperature T of the first vibrating element XI from the temperature T of the second vibrating element X2 according to the frequency-temperature characteristics of (1) and the oscillation frequency f2 output from the second oscillation circuit 61b.

[0168] In a case where the output selection section 92 selects the oscillation frequency f3 output from the third oscillation circuit 61c as the frequency f to be output to the control signal output circuit 63, the temperature estimation section 68 can estimate the temperature T of the first vibrating element XI from the temperature T of the third vibrating element X3 according to the frequency-temperature characteristics of (2) and the oscillation frequency f3 output from the third oscillation circuit 61c.

[0169] f1 = f 10 {1 + α2(T - T 10 ) 3 + β2(T - T 10 )+ γ2}... (1)

[0170] f2 = f 11 {1 + α3(T - T 11 ) 3 + β3(T - T 11 )+ γ3}... (2)

[0171] Further, the compensation voltage operation section 69 has, for example, a third-order function generator as the temperature characteristics of the first oscillation circuit 61a, and is configured to operate the compensation voltage ΔV from the temperature T according to the following (3) to (5) formulas.

[0172] ΔV=V0(Δf / f0)……(3)

[0173] Δf / f0=α1(T-T0) 3 +β1(T-T0)+γ1……(4)

[0174] ΔV=V0{α1(T-T0) 3 +β1(T-T0)+γ1}……(5)

[0175] Among them, α1, β1, γ1, α2, β2, γ2 and α3, β3, γ3 are inherent constants of the first oscillation circuit 61a, the second oscillation circuit 61b and the third oscillation circuit 61c, respectively, which can be determined by changing the temperature or reference voltage in various ways and measuring the output frequency. Furthermore, Δf = f - f0, and f 10 In the second oscillation circuit 61b, at the reference temperature T 10 Apply a reference voltage V 10 The output frequency f is obtained at that time. 11 In the third oscillation circuit 61c, at the reference temperature T 11 Apply a reference voltage V 11 The output frequency obtained at that time.

[0176] When a control voltage V is input to the input terminal 64b of the second oscillation circuit 61b... 10 At that time, in the second oscillation circuit 61b, according to the temperature T of the second vibrating element X2, oscillation occurs with thickness shear vibration of the fundamental wave at the oscillation frequency f1 obtained by the above equation (1). When the control voltage V is input to the input terminal 64c of the third oscillation circuit 61c... 11 At that time, in the third oscillation circuit 61c, according to the temperature T of the third vibration element X3, the fundamental wave is oscillated by thickness shear vibration at the oscillation frequency f2 obtained by the above equation (2).

[0177] The output selection circuit 90 outputs one of the oscillation frequency f2, which is the second oscillation signal output from the second oscillation circuit 61b, and the oscillation frequency f3, which is the third oscillation signal output from the third oscillation circuit 61c, as the output signal f from the output selection circuit 90, and outputs it to the control signal output circuit 63 based on the temperature detected by the temperature sensor 93.

[0178] The frequency f is input to the temperature estimation section 68 via the frequency detection section 67. The temperature estimation section 68 estimates the temperature T of the first vibrating element XI based on the temperature T of either the second vibrating element X2 or the third vibrating element X3 selected by the selection section 92 of the output selection circuit 90. Then, in the compensation voltage operation section 69, a compensation voltage ΔV is calculated based on the temperature T obtained by the temperature estimation section 68, and the control voltage V is applied to the first oscillation circuit 61a as a control signal via the addition section 70 C In the first oscillation circuit 61a, the oscillation frequency of the first oscillation signal, i.e., the set frequency fo, is caused to vibrate in thickness shear vibration. C The set frequency fo of the corresponding first oscillation signal is caused to vibrate in thickness shear vibration.

[0179] That is, at the temperature T, the oscillation frequency of the first oscillation circuit 61a deviates from the set frequency fo by the difference (T - To) between the temperature T and the reference temperature To in accordance with the frequency-temperature characteristic of the first oscillation circuit 61a. However, since the control voltage V is applied to the first oscillation circuit 61a which is lower or higher than the reference voltage Vo by an amount corresponding to the difference, the output frequency, i.e., the set frequency fo, which has compensated for the difference can be obtained. C

[0180] In the oscillator 100 of the present embodiment, the frequency-temperature characteristic of the first vibrating element XI is set to a characteristic suitable for oscillation signal output, and the frequency-temperature characteristic of the second vibrating element X2 and the frequency-temperature characteristic of the third vibrating element X3 can be adjusted to characteristics suitable for temperature detection, so that the set frequency fo output from the first vibrating element XI can be temperature-compensated rapidly and with high accuracy based on the oscillation frequency f2 of the second vibrating element X2 and the oscillation frequency f3 of the third vibrating element X3. Therefore, a high-accuracy oscillator 100 in which the set frequency fo is stable can be obtained.

[0181] Further, if the frequency-temperature characteristic of the second vibrating element X2 and the frequency-temperature characteristic of the third vibrating element X3 are different characteristics, the temperature T of the first vibrating element XI can be estimated with higher accuracy based on the temperature T of the vibrating element having the frequency-temperature characteristic which has a larger frequency change amount at the temperature detected by the temperature sensor 93 among the second vibrating element X2 and the third vibrating element X3. Therefore, a high-accuracy oscillator 100 in which the set frequency fo is more stable can be obtained.

[0182] 10. Tenth Embodiment

[0183] Reference Figure 30 and Figure 31 ​The circuit structure of the oscillator 100a in the tenth embodiment will be described. Structures identical to those in the ninth embodiment will be labeled with the same reference numerals, and repeated descriptions will be omitted.

[0184] This embodiment calculates the sum or difference between the oscillation frequency f2 of the second vibrating element X2 and the oscillation frequency f3 of the third vibrating element X3, and uses the frequency f calculated in this way as a temperature detection signal.

[0185] like Figure 30 As shown, a control signal output circuit 63b is provided between the first oscillation circuit 61a, the second oscillation circuit 61b, and the third oscillation circuit 61c. This control signal output circuit 63b is used to estimate the temperature of the first oscillation element X1 based on the oscillation frequency f2, which is the second oscillation signal output from the second oscillation circuit 61b of the second oscillation element X2, and the oscillation frequency f3, which is the third oscillation signal output from the third oscillation circuit 61c of the third oscillation element X3. It then calculates a control voltage V, which is the set frequency f0 of the first oscillation signal, and which is the control signal, that can be obtained by the first oscillation circuit 61a at that temperature. C (V C =V0-ΔV).

[0186] The control signal output circuit 63b includes frequency detection units 67b and 67c, temperature estimation unit 68b, compensation voltage calculation unit 69, and addition unit 70.

[0187] The oscillation frequency f2 output from the second oscillation circuit 61b is input to the temperature estimation unit 68b via the frequency detection unit 67b. The oscillation frequency f3 output from the third oscillation circuit 61c is input to the temperature estimation unit 68b via the frequency detection unit 67c.

[0188] The temperature estimation unit 68b calculates the difference (f3-f2) between the oscillation frequency f2 and the oscillation frequency f3, and estimates the temperature T of the first vibrating element X1 based on the frequency difference (f3-f2) obtained through calculation and the relationship data between the frequency difference (f3-f2) and the temperature T.

[0189] Figure 31 This is a graph showing an example of the relationship between the frequency difference (f3-f2) and temperature T, obtained by subtracting the cubic curve of the frequency-temperature characteristic of the third vibrating element X3 from the cubic curve of the frequency-temperature characteristic of the second vibrating element X2. According to... Figure 31 It can be seen that the calculated frequency difference (f3-f2) is roughly proportional to the temperature T.

[0190] The temperature estimation unit 68b has a storage unit that stores relationship data of the difference (f3-f2) in frequency and the temperature T, a calculation unit that calculates the difference (f3-f2) in oscillation frequency f2 and oscillation frequency f3, and a readout unit that reads out the temperature T corresponding to the difference (f3-f2) in frequency from the relationship data in the storage unit not shown.

[0191] Instead of calculating the difference (f3-f2) in oscillation frequency f2 and f3, the sum (f2+f3) of oscillation frequency f2 and f3 can be calculated, and the temperature T can be calculated by referring to the relationship data of the sum (f2+f3) of frequency and the temperature T. Further, instead of calculating the difference in oscillation frequency f2 and f3, the difference in V2 obtained by voltage conversion of oscillation frequency f2 and V3 obtained by voltage conversion of oscillation frequency f3 can be calculated, and the temperature T can be calculated by referring to the relationship data of the difference (V3-V2) in voltage and the temperature T.

[0192] In the oscillator 100a of the present embodiment, the frequency-temperature characteristic of the first vibration element Xl is set to a characteristic suitable for oscillation signal output, and the frequency-temperature characteristics of the second vibration element X2 and the third vibration element X3 are adjusted to characteristics suitable for temperature detection, and thus the set frequency fO output from the first vibration element Xl can be rapidly and highly accurately temperature-compensated based on the oscillation frequency f2 of the second vibration element X2 and the oscillation frequency f3 of the third vibration element X3. Therefore, a highly accurate oscillator 100a in which the set frequency fO is stable can be obtained.

[0193] Further, if the frequency-temperature characteristic of the second vibration element X2 and the frequency-temperature characteristic of the third vibration element X3 are different characteristics, and the temperature T of the first vibration element Xl is estimated based on the sum or difference of the oscillation frequency f2 of the second vibration element X2 and the oscillation frequency f3 of the third vibration element X3, the temperature T of the first vibration element Xl can be more highly accurately estimated. Therefore, a highly accurate oscillator 100a in which the set frequency fO is more stable can be obtained.

Claims

1. A vibrating element, wherein, The vibration element has: a quartz substrate having a first vibration portion, a second vibration portion arranged on one side of the first vibration portion in a first direction of the first vibration portion, and a third vibration portion arranged on one side of the first vibration portion in the first direction and juxtaposed with the second vibration portion in a second direction perpendicular to the first direction; a pair of first excitation electrodes formed on both main surfaces of the quartz substrate in the first vibration portion; a pair of second excitation electrodes formed in the second vibration portion in a manner sandwiching the second vibration portion in a thickness direction of the quartz substrate; and a pair of third excitation electrodes formed in the third vibration portion in a manner sandwiching the third vibration portion in the thickness direction of the quartz substrate, at least one of the second excitation electrodes of the pair of second excitation electrodes is formed on a first inclined surface inclined with respect to the both main surfaces, at least one of the third excitation electrodes of the pair of third excitation electrodes is formed on a second inclined surface inclined with respect to the both main surfaces, the second inclined surface is inclined with respect to the first inclined surface, the first vibration portion, the second vibration portion, and the third vibration portion are formed in the common quartz substrate, and the first inclined surface and the second inclined surface are formed by cutting the common quartz substrate at different cutting angles.

2. The vibration element according to claim 1, wherein cutting angles of the both main surfaces, the first inclined surface, and the second inclined surface are different.

3. The vibration element according to claim 1 or 2, wherein a cutting angle of the first inclined surface is smaller than cutting angles of the both main surfaces, a cutting angle of the second inclined surface is larger than the cutting angles of the both main surfaces.

4. The vibration element according to claim 1 or 2, wherein frequency-temperature characteristics of the first vibration portion, the second vibration portion, and the third vibration portion are different.

5. The vibration element according to claim 4, wherein an amount of frequency change of the frequency-temperature characteristics of the second vibration portion and the third vibration portion is larger than an amount of frequency change of the frequency-temperature characteristics of the first vibration portion.

6. The vibration element according to claim 1 or 2, wherein the first inclined surface and the second inclined surface are inclined in a manner that thicknesses of the second vibration portion and the third vibration portion become thinner as they approach each other.

7. The vibration element according to claim 1 or 2, wherein the first inclined surface and the second inclined surface are inclined in a manner that thicknesses of the second vibration portion and the third vibration portion become thinner as they move away from each other.

8. The vibration element according to claim 1 or 2, wherein the second vibration portion has a surface parallel to the first inclined surface on a side opposite the first inclined surface, the third vibration portion has a surface parallel to the second inclined surface on a side opposite the second inclined surface.

9. The vibration element according to claim 1 or 2, wherein the first vibration portion is formed with a convex portion on at least one main surface.

10. The vibration element according to claim 1 or 2, wherein An end portion of the vibration element in the first direction has a fixing portion that fixes the vibration element to a package.

11. The vibration element according to claim 10, wherein The fixing portion is provided at an end portion on the side of the second vibration portion and the third vibration portion.

12. The vibration element according to claim 1 or 2, wherein At least one of a through-hole and a thin-walled portion is provided between the second vibration portion and the third vibration portion.

13. The vibration element according to claim 1 or 2, wherein At least one of a through-hole and a thin-walled portion is provided between the first vibration portion, the second vibration portion, and the third vibration portion.

14. An oscillator, wherein, The oscillator has: The vibration element according to any one of claims 1 to 13; a first oscillation circuit electrically connected to the first excitation electrode, which outputs a first oscillation signal; a second oscillation circuit electrically connected to the second excitation electrode, which outputs a second oscillation signal; a third oscillation circuit electrically connected to the third excitation electrode, which outputs a third oscillation signal; and a control signal output circuit that inputs at least one of the second oscillation signal and the third oscillation signal, and outputs a control signal that controls an oscillation frequency of the first oscillation signal, based on the input signal. The oscillator further has:

15. The oscillator of claim 14, wherein, a temperature sensor; and an output selection circuit that inputs the second oscillation signal and the third oscillation signal, and selectively outputs the second oscillation signal or the third oscillation signal, based on a temperature detection result of the temperature sensor, the control signal output circuit outputs the control signal based on an output signal of the output selection circuit.

16. The oscillator according to claim 15, wherein the output selection circuit selects and outputs one of the second oscillation signal and the third oscillation signal that has a larger frequency-temperature characteristic in a change amount of a frequency at a temperature detected by the temperature sensor. ​ ​

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