Piezoelectric devices

Abstract

The present invention provides a piezoelectric device having a structure in which a piezoelectric vibrating element is connected to a container via a base, and further provides a piezoelectric device having a base structure suitable for mass production. [Solution] The piezoelectric device 10 comprises a container 13 having a rectangular recess 13a for a piezoelectric vibrator 11, a piezoelectric vibrator cantilevered to the bottom surface of the recess via a base 15 on a first side wall side 13ya corresponding to the first side of the recess, and a base having a rectangular shape in plan. The base has a first wiring pattern 15a on a first surface for connection with the piezoelectric vibrator, a second wiring pattern 15b on a second surface for connection with the container, and a third wiring pattern 15c on a side wall for connecting the first and second wiring patterns. Each of the first and second wiring patterns has a recessed portion 15d on the first side wall side of the container, and the third wiring pattern is provided on the side wall of the base that is opposite to the side wall facing the first side wall.

Description

Technical Field

[0001] The present invention relates to a piezoelectric device, and particularly to a piezoelectric device having a structure in which a piezoelectric vibrating piece is connected to a container via a pedestal.

Background Art

[0002] Typical examples of piezoelectric devices include crystal devices such as crystal oscillators and crystal oscillators using AT-cut crystal vibrating pieces. Further, there is a so-called crystal oscillator with a built-in temperature sensor in which an AT-cut crystal vibrating piece and a temperature sensor are built in one container.

[0003] Typical examples of crystal oscillators with a built-in temperature sensor are those having a so-called one-room structure and an H-type structure. The former is one in which a crystal vibrating piece and a temperature sensor are mounted in one room and hermetically sealed (for example, paragraph 75, FIG. 7, etc. of Patent Document 1). The latter is one in which a first room in which a crystal vibrating piece is mounted and a second room in which a temperature sensor is mounted are laminated back to back, and the first room is hermetically sealed (for example, the summary of Patent Document 2, FIG. 1, etc.).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] With the miniaturization and increased frequency of electronic devices, there is a demand for smaller and more precise piezoelectric devices as described above. One way to achieve this is to interpose a crystal base between the crystal oscillator and the container in which it is mounted. The applicant of this application has disclosed a specific example of this in Patent Document 3 (see, for example, Figure 4, paragraph 4 of Patent Document 3), and has further proposed more specific technologies in Japanese Patent Application No. 2024-124115 and Japanese Patent Application No. 2024-154016. However, as we proceeded with the mass production of piezoelectric devices using a base, it became clear that if the arrangement of the wiring pattern on the base, which electrically connects the base to the crystal vibrator and the container, and the shape of the base were not carefully considered, problems such as electrical short circuits between the wiring pattern on the base and the container, or contact between the base and the container wall, would occur, impairing mass production. Specifically, when mass-producing small and high-precision piezoelectric devices such as those with external dimensions of approximately 1.6 mm on the long side, 1.2 mm on the short side, 1.2 mm on the long side, 1.0 mm on the short side, and 1.0 mm on the long side, 0.8 mm on the short side (so-called 1612, 1210, and 1008 sizes), the size of the recess in the container where the piezoelectric vibrator is mounted becomes extremely narrow. Therefore, considerable ingenuity is required in designing the base provided inside. This application has been made in view of these points, and therefore the object of this application is to provide a piezoelectric device having a base between a piezoelectric vibrator and a container on which the piezoelectric vibrator is mounted, wherein the base has a structure suitable for mass production. [Means for solving the problem]

[0006] To achieve this objective, the present invention provides a piezoelectric device comprising: a container having a rectangular recess containing a piezoelectric vibrator; a rectangular piezoelectric vibrator cantilevered to the bottom surface of the recess via a base on the first side wall corresponding to the first side of the recess; and a rectangular base. The base has a first wiring pattern on its first surface for connection to the piezoelectric vibrator, a second wiring pattern on its second surface opposite to the first surface for connection to the container, and a third wiring pattern on its side wall for connecting the first and second wiring patterns, Each of the first and second wiring patterns has a shape that includes a recessed portion on at least the first side wall side of the base that recedes from the edge of the base toward the center, The third wiring pattern is provided on the side wall of the base that is located on the side wall opposite to the side wall facing the first side wall.

[0007] In carrying out this invention, the first wiring pattern and the second wiring pattern may each have a shape that includes a further recessed portion on the side of the base where the first side wall and the side wall opposite it intersect with the two side walls.

[0008] In carrying out this invention, it is preferable that the base has notches at both ends of the side wall facing the first side wall. Typically, chamfered sections are preferred as notches. With a configuration that includes notches, the risk of the base contacting the side wall of the recess in the container is reduced compared to a configuration that does not include notches, so the base can be placed closer to the corner of the recess in the container, thereby improving the mass production of piezoelectric devices.

[0009] In carrying out this invention, it is preferable that the container comprises a ceramic main body and a metal ring-shaped member connected to the main body and forming the side wall of the recess. There is an increasing demand for miniaturization of piezoelectric vibrators. Moreover, there is a high demand for shielding structures to reduce the influence of external electromagnetic waves. This preferred example of a container easily satisfies these requirements. Furthermore, in the case of the present invention, since the first wiring pattern, second wiring pattern, and third wiring pattern of the base are arranged so as not to contact the side wall of the container recess, even if the recess is made of a metal ring-shaped member, no electrical short circuit occurs between the first to third wiring patterns and the metal ring-shaped member.

[0010] In carrying out this invention, the piezoelectric vibrator is a quartz crystal vibrator with a planar shape and an AT cut, which is cantilevered to the base at two points along the first side thereof. Preferably, the base includes the same crystal axis as the crystal axis of the quartz crystal along the two points of the quartz crystal vibrator, and is connected and fixed to the quartz crystal vibrator in such a way that its crystal axis coincides with that of the quartz crystal vibrator. With this configuration, in addition to the effects of the present invention due to the shape of the base and the arrangement of the wiring pattern, the effect of reducing the degradation of the characteristics of the quartz device caused by the difference in thermal expansion coefficients between the quartz crystal vibrator and the base can also be obtained.

[0011] In carrying out this invention, it is preferable that the piezoelectric vibrator is a piezoelectric vibrator with a built-in temperature sensor, comprising a second recess containing a temperature sensor and the temperature sensor contained within the second recess. In this preferred example, the piezoelectric vibrator with a built-in temperature sensor may have a single-chamber structure or an H-shaped structure. The effects of the present invention can also be applied to a piezoelectric vibrator with a built-in temperature sensor. [Effects of the Invention]

[0012] According to this invention, since the first, second, and third wiring patterns provided on the base are each arranged in a predetermined structure and configuration, even if the recess of the container is made of, for example, a metal ring-shaped member, the risk of electrical contact between the wiring patterns and the metal ring-shaped member can be avoided. Furthermore, even if the member constituting the recess is an insulating member rather than a metal ring-shaped member, the first, second, and third wiring patterns will not come into contact with the insulating member, thus reducing the effects of, for example, parasitic capacitance. Therefore, according to this invention, mounting the base into the recess of the container becomes easier, thereby improving the mass production capability of piezoelectric devices. [Brief explanation of the drawing]

[0013] [Figure 1] This is a diagram illustrating the crystal oscillator 10 of the first embodiment. [Figure 2] It is a diagram for explaining especially the pedestal 15 of the crystal oscillator 10 of the first embodiment. [Figure 3] It is a diagram for explaining a preferable relationship between the crystal piece and the pedestal. [Figure 4] It is a diagram for explaining the thickness of the crystal pedestal and the stress relaxation state. [Figure 5] It is a diagram for explaining the crystal oscillator 30 of the second embodiment. [Figure 6] It is a diagram for explaining the crystal oscillator 40 of the third embodiment. [Figure 7] It is a diagram for explaining an example of a method for manufacturing the pedestal. [Figure 8] It is a diagram for explaining a preferable mounting state of the pedestal manufactured by the manufacturing method example. [Figure 9] It is a diagram for explaining a specific example of the recess for the temperature sensor. [Figure 10] It is a diagram for explaining a specific example of the crystal piece.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of this invention will be described with reference to the drawings. Note that each drawing used in the description only schematically shows the invention to an extent that can be understood. Also, in each drawing used in the description, the same components are denoted by the same numbers, and the description thereof may be omitted in some cases. Further, the structural examples, members used, etc. described in the following description are merely preferred examples within the scope of this invention. Therefore, the present invention is not limited only to the following embodiments.

[0015] 1. First Embodiment 1-1. Structural Explanation As a first embodiment, an example of applying the present invention to a single-chamber type quartz oscillator with a built-in temperature sensor will be described. Figures 1 and 2 illustrate this example. In particular, Figure 1(A) is a top view of the quartz oscillator 10, Figure 1(B) is a cross-sectional view along the PP line in Figure 1(A), and Figure 1(C) is a bottom view. Figure 2(A) is a perspective view mainly focusing on the mounting state of the base 15, and Figure 2(B) is a side view, top view, and rear view (perspective view) of the base 15. However, in Figure 1(A), the piezoelectric vibrator 11, lid member 19, conductive adhesive 21, etc. shown in Figure 1(B) are omitted.

[0016] This crystal oscillator 10 comprises a piezoelectric vibrator 11, a container 13, a base 15, a temperature sensor 17, and a lid member 19. The piezoelectric vibrator 11 can be any vibrator made of any piezoelectric material with a rectangular shape in plan view, but in this embodiment, it is made of a rectangular, specifically, AT-cut quartz vibrator 11 with a rectangular shape in plan view. This is because the AT-cut quartz vibrator 11 is relatively inexpensive and provides good frequency-temperature characteristics compared to other piezoelectric vibrators. The quartz crystal oscillator 11 is equipped with excitation electrodes 11a on its front and back main surfaces, and further equipped with lead electrodes 11b (see Figure 2(A)) in the region extending from each excitation electrode 11a toward one side of the quartz crystal oscillator 11. The quartz crystal oscillator 11 is mounted in a recess 13a (hereinafter also referred to as the first recess 13a) of the container 13. In detail, the quartz crystal oscillator 11 is cantilevered at two positions along one side of the recess 13a via a base 15 and conductive adhesive 21, and the base 15 is connected to the container 13 by conductive adhesive 21. However, in the case of the quartz crystal oscillator 10 of the first embodiment, since it is a single-chamber type quartz crystal oscillator with a built-in temperature sensor, the container 13 further includes a second recess 13b (details described later) for mounting the temperature sensor 17. Therefore, the base 15 is connected to the surrounding portion of the first recess 13a where the second recess 13b is provided by conductive adhesive 21. Thus, in practice, the crystal oscillator 11 is electrically connected to the adhesive pad 13c by the extraction electrode 11b, the conductive adhesive 21, the first wiring pattern 15a, second wiring pattern 15b, and third wiring pattern 15c of the base 15 (see Figure 2(B)), which will be described in detail later, and the conductive adhesive 21.

[0017] The container 13 is a container having a first recess 13a with a rectangular planar shape that encloses the quartz crystal oscillator 11. This container can be made of any suitable material, but in this embodiment, the container 13 is a container comprising a ceramic main body 13x and a metal ring-shaped member 13y that is connected to the main body 13x, for example by brazing, and forms the side wall of the recess 13a. Moreover, in the case of this container 13, as mentioned above, the main body 13x is provided with a second recess 13b for mounting the temperature sensor 17. Two adhesive pads 13c for connecting the base 15 are provided on one end of the main body 13x of the container 13. In addition, a second recess 13b, which is rectangular in plan view, is provided in the area of ​​the main body 13x other than the area where the adhesive pads 13c are provided, for mounting the temperature sensor 17, and an adhesive pad 13d for connecting the temperature sensor 17 is provided on the bottom surface of this second recess 13z. The temperature sensor 17 is connected to this adhesive pad 13d. Furthermore, an external connection terminal 13e for connecting the crystal oscillator 10 to any external electronic device is provided on the outer bottom surface of the main body 13x. The external connection terminal 13e is electrically connected to the adhesive pad 13c for the base and the adhesive pad 13d for the temperature sensor by via wiring or the like (not shown).

[0018] The base 15 has a rectangular shape in plan view. The length of the base 15 (horizontal direction in Figure 1) may be about the same as the length of the crystal oscillator 11, or it may be shorter, but it is preferable that it be shorter on the support side than the excitation electrode 11a of the crystal oscillator 11. This is because a shorter base 15 makes it less likely for problems such as the base coming into contact with the crystal oscillator 11 to occur. Also, the width of the base 15 (vertical direction in Figure 1) should be more preferably larger than the width of the crystal oscillator 11. The length and width of the base should be appropriately determined considering the size of the crystal oscillator, specifically the length of the longer side of the crystal oscillator 11 and the width of the first recess 13a. Furthermore, it is preferable that the base 15 includes the same crystal axis as the crystal along the two support points connected to the base of the crystal vibrator 11, and that it is connected and fixed to the crystal vibrator 11 in such a way that its crystal axis coincides with that of the crystal vibrator 11 (details will be described later with reference to Figure 3, etc.). Furthermore, as shown in Figure 2(B), the base 15 has a first wiring pattern 15a on its first surface for connection to the crystal oscillator 11, a second wiring pattern 15b on its second surface opposite to the first surface for connection to the container 13, and a third wiring pattern 15c on its side wall for connecting the first and second wiring patterns. Moreover, a feature of the present invention is that each of the first wiring pattern 15a and the second wiring pattern 15b has a recessed portion 15d on at least the side of the first side wall 13ya of the container 13 that recedes from the edge of the base toward the center. The recessed dimension S1 of the recessed portion 15d should be such that even if the base 15 comes into contact with the metal ring-shaped member, the first wiring pattern 15a does not come into contact (short circuit) with the metal ring-shaped member 13y. If the recessed dimension is too large, the surface normality of the wiring pattern becomes small, which is undesirable. Although not limited to this, the recessed dimension S1 is preferably about 30 to 50 μm.

[0019] Furthermore, in this embodiment, the first wiring pattern 15a and the second wiring pattern 15b each have a recessed portion 15e on the side of the base 15 where it intersects with the side wall opposite the first side wall 13ya of the container. The recessed dimension S2 of the recessed portion 15e can be determined in the same way as the dimension S1 described above. S1 and S2 may be the same dimension or different dimensions. Furthermore, in this embodiment, the second wiring pattern 15b has a recessed portion 15f, in addition to the recessed portion 15d, located near the center of the edge of the base 15 where the recessed portion 15d is provided, extending from the edge of the base 15 toward the center of the base 15, with a recessed portion S3 that is larger than the recessed portion 15d. This recessed portion 15f, which will be explained in detail later, is a recessed portion that prevents the second wiring pattern 15b from being damaged by the breaking jig used when breaking off each base from the wafer after many bases 15 have been manufactured in wafer form. The width of the recessed portion 15f and the recessed portion S3 are determined considering the size of the breaking jig. However, if the width of the recessed portion 15f and the recessed portion S3 are too large, the area of ​​the second wiring pattern 15b will be reduced, which is undesirable in terms of conductivity, so it is good to take this into consideration as well. Furthermore, the third wiring pattern 15c is provided on the side wall of the base 15 that is opposite to the side wall facing the first side wall 13ya of the container. By positioning the third wiring pattern 15c as described above, the third wiring pattern 15c is on a surface that does not face the first side wall 13ya of the container 13, thus preventing the third wiring pattern 15c from coming into contact with the first side wall 13ya of the container 13.

[0020] Furthermore, in this embodiment, the base 15 is provided with notches 15x at both ends of the side wall facing the first side wall 13ya of the container 13. The notches 15x are preferably made of C-chamfered portions. With the configuration that includes notches, the risk of the base 15 contacting the side wall of the recess of the container 13 is reduced compared to when not included, so the base can be placed closer to the corner of the recess of the container, thereby improving the mass production efficiency of the piezoelectric device. The size of the notches 15x is not limited to this, but for example, in terms of C dimension, it is good to have a size of about 20 to 70 μm, preferably about 30 to 50 μm.

[0021] The temperature sensor 17 is preferably constructed using a thermistor. However, the temperature sensor 17 is not limited to a thermistor; other components, such as a diode, can also be used. This is because a temperature sensor can be realized by utilizing the temperature dependence of the diode's PN junction. The lid member 19 can be any material depending on the sealing method. If the sealing method is seam sealing, the lid member 19 can be made of, for example, Kovar material with nickel plating. The conductive adhesive 21 is not limited to this, but it is preferable to use a silicone-based conductive adhesive. In this embodiment, the same conductive adhesive is used for connecting the quartz crystal, the base, and the container, but different adhesives may be used. Alternatively, a fastening member other than a conductive adhesive may be used.

[0022] 1-2. The necessity of aligning the crystal axes of the quartz vibrator and the quartz base. As stated above, it is preferable that the base 15 includes the same crystal axis as the crystal axis of the quartz crystal along the two support points of the quartz crystal vibrator 11, and that it is connected and fixed to the quartz crystal vibrator 11 in such a way that its crystal axis coincides with that of the quartz crystal vibrator 11. The reason for this is explained below. The inventor of this application performed the following evaluation using the finite element method. Specifically, four types of analytical models were created, each modeled after the quartz oscillator 10 described using Figure 1, with the crystal axis conditions of the quartz crystal, the material of the base, and the crystal axis conditions set as shown in the table below, in relation to the direction in which the two bonding points of the AT-cut quartz crystal vibrator are aligned. The von Mises stress generated at the center point of the quartz crystal vibrator in each analytical model was then determined when the temperature of each analytical model was changed from 25°C to 105°C. The results are shown in the table below. TIFF2026126766000002.tif83143

[0023] From the table above, it can be seen that the stress generated at the center of the quartz crystal due to the above temperature change is approximately 366-386 kPa in analysis model 1 and analysis model 2, while it is approximately 10 kPa in analysis model 3 and analysis model 4, which is about 1 / 37th of the original stress. It can be seen that the stress can be reduced by using a quartz crystal base with a crystal axis that matches the crystal axis corresponding to the line segment connecting the two bonding points of the quartz crystal base, with the appropriate axial relationship. Therefore, the results in the table above show that appropriately selecting and using an AT-cut quartz base or a Z-cut quartz base, taking into account the bonding direction of the two points of the AT-cut quartz crystal oscillator, is effective in reducing thermal stress in the bonded structure of the quartz oscillator. The point about aligning the crystal axes of the quartz vibrating piece 11 and the base 15, as described above, will be explained in detail with reference to Figure 3. In Figure 3, the coordinate axes X, Y', and Z' represent the crystal axes of the quartz derived from the AT cut. Axes Y' and Z' indicate that the axes are shifted from the original Y and Z axes of the quartz according to the cutting angle of the AT cut.

[0024] Figure 3(A) illustrates the bases when the crystal oscillator 11 is connected to bases 15p and 15q at two locations along the X-axis of the crystal. Specifically, the two lead electrodes 11b are located at two separate locations along the X-axis of the crystal oscillator 11, and the crystal oscillator 11 is bonded to base 15p or base 15q at these locations. In this case, bases 15p and 15q include the X-axis of the crystal parallel to their plane and can connect to the crystal oscillator 11 at two locations along this X-axis. Specifically, the base 15p shown in the lower left of Figure 3(A) is made of an AT-cut crystal and has a first wiring pattern 15a at two locations along the X-axis of the crystal. Alternatively, the base 15q shown in the lower right of Figure 3(A) may be made of a Z-cut crystal and also has a first wiring pattern 15a at two locations along the X-axis of the crystal.

[0025] Figure 3(B) is an explanatory diagram of a base when the crystal oscillator 11 is connected to the base 15r at two points along the Z' axis of the crystal. In this case, the base 15r contains the Z axis or Z' axis of the crystal within its plane and is capable of connecting the crystal oscillator 11 at two points along this Z axis or Z' axis. Specifically, the base 15r is made of an AT-cut crystal and has a first wiring pattern 15a along the Z' axis of the crystal of the base, corresponding to the lead electrode 11b of the crystal oscillator 11. Furthermore, in each of the above-mentioned bases 15p, 15q, and 15r, the X-axis and Z-axis of the base do not necessarily have to be exactly the same as the X-axis and Z-axis of the crystal oscillator. Within the scope of the objectives of the present invention, there may be some angular misalignment or deviation in parallelism between the two axes.

[0026] 1-3. Base thickness and stress in the quartz crystal vibrator Furthermore, as another evaluation using the finite element method, we investigated how the thickness of the quartz base affects the stress in the quartz crystal oscillator. Specifically, in analysis model 4 in the table above, eight different analysis models were created by varying the thickness T of the AT-cut quartz base (see Figure 2(B)) from 10 μm to 80 μm in 10 μm steps. Then, the von Mises stress generated at the center point of the quartz crystal oscillator in each analysis model was determined when the temperature was changed from 25°C to 105°C. Figure 4 shows the results, with the thickness of the base on the horizontal axis and the stress value (relative value) on the vertical axis. However, the quartz crystal oscillator 11 was analyzed with an oscillation frequency of 76.8 MHz. Figure 4 shows that, using the stress at a base thickness T of 10 μm as a baseline, the stress becomes approximately one-third at a base thickness T of 20 μm, approximately one-sixth at a base thickness T of 30 μm, and increases to about one-fifth of the baseline up to a base thickness T of 60 μm. It can be seen that the stress tends to decrease as the base thickness T increases further. Therefore, it can be said that a thicker base T is better, but there is a limit to how thick it can be, as it will no longer fit inside the crystal oscillator's casing. Taking these factors into consideration, the following can be said about the appropriate thickness of the base.

[0027] In this analysis model, the thickness of the quartz crystal is approximately 22 μm (derived from the oscillation frequency of 76.8 MHz). Using the 22 μm thickness of the quartz crystal as a reference, the thickness T of the base should be 20 μm ≤ T, or greater than or equal to the thickness of the quartz crystal. Considering that it can be housed in a container, 20 μm ≤ T ≤ 70 μm, or the thickness of the quartz crystal ≤ T ≤ 70 μm is preferable. Furthermore, the stress is smaller in the range from about 20 μm to 60 μm, where the thickness T of the base is slightly thinner than the thickness of the quartz crystal. Therefore, the thickness T of the base should be 20 μm ≤ T ≤ 60 μm, and even better, 30 μm ≤ T ≤ 60 μm. Generalizing the above findings, we can also say the following. When the thickness of the quartz crystal vibrator is t and the thickness of the base is T, T≧0.9t is preferable. Preferably, 0.9t≦T≦3.1t or t≦T≦3.1t is preferable, more preferably 0.9t≦T≦2.7t or t≦T≦2.7t is preferable, and even more preferably 1.3t≦T≦2.7t is preferable. Here, the value 0.9 is based on 20 / 22≈0.9 in the above values. The value 3.1 is based on 70 / 22≈3.18. The value 2.7 is based on 60 / 22≈2.7. The value 1.3 is based on 30 / 22≈1.36.

[0028] 2. Second Embodiment Next, a second embodiment will be described. The difference between the second embodiment and the first embodiment is that the present invention is applied to a quartz oscillator with a built-in temperature sensor of an H-type structure. Figure 5 is an explanatory diagram for this, and is a cross-sectional view of the quartz oscillator 30 of the second practical embodiment, corresponding to the cross-sectional view in Figure 1(B). A first chamber containing a quartz crystal oscillator 11 and a second chamber containing a temperature sensor 17 are stacked back-to-back, with the first chamber hermetically sealed. The base 15 of the present invention and the quartz crystal oscillator 11 are mounted inside the first chamber in the same manner as in the first embodiment.

[0029] 3. Third Embodiment Next, the crystal oscillator 40 of the third embodiment will be described with reference to Figures 6(A) and (B). Here, Figures 6(A) and (B) are plan views and cross-sectional views, respectively, corresponding to Figures 1(A) and (B). The first and second embodiments described above were examples in which the present invention was applied to a quartz crystal oscillator with a built-in temperature sensor, but the quartz crystal oscillator 40 of the third embodiment is an example in which the present invention was applied to a simple quartz crystal oscillator without a built-in temperature sensor.

[0030] 4. Method for manufacturing the base and the crystal oscillator of the fourth embodiment Next, an example of a method for manufacturing the base 15 will be described with reference to Figures 7(A) and (B). In this example, a number of bases 15 are manufactured in a matrix on a quartz wafer, such as an AT-cut quartz wafer 50, using known photolithography techniques (Figure 7(A)). Each base 15 is connected to the frame 50a of the quartz wafer 50 via a connecting portion 50b. When separating each base 15 from the quartz wafer 50, the recessed portion 15f on the side of the base 15 where the second wiring pattern 15b is formed is pressed with a breaking jig. Then, the base can be broken off from the quartz wafer 50 at the connecting portion 50b and separated into individual pieces (Figure 7(B)). However, when the individual base 15 is broken apart, a portion of the connecting part often remains, resulting in a base with protrusions 15s. In this example, since there are two connecting parts, two protrusions 15s are generated. When manufacturing a quartz oscillator using a base 15 having a projection 15s, as shown in Figure 8, a partial perspective view corresponding to Figure 2(A), the base 15 is connected to the adhesive pad 13c of the container such that the projection 15s side faces the center of the quartz oscillator 11 and not the first side wall 13ya side of the container 13. This prevents the projection 15s from contacting the side wall of the container 13. Moreover, the projection is expected to have a wedge effect on the adhesive when bonding the base to the container 13, and an improvement in the adhesive strength of the base to the container can also be expected.

[0031] 5. Regarding the recess for the temperature sensor Next, a specific example of the recess 13b (second recess 13b) for the temperature sensor exemplified in the first embodiment will be described. This description will be given with reference to Figures 9(A) and (B). Here, Figures 9(A) and (B) are plan views of the container 13 similar to that in Figure 1(A), and Figure 9(C) is a cross-sectional view along the RR line in Figure 9(B). An example of the second recess 13b in this invention is a recess that is closed in a planar manner and has a predetermined depth, as shown in Figure 9(A). Another example of the second recess 13b is a recess where the portion of the container 13 where the adhesive pad 13c for bonding the quartz crystal is provided is a convex portion 13h, 13i, and the portion other than the convex portions 13h, 13i is lower and serves a recess-like function, as shown in Figure 9(B). In the former case (Figure 9(a)), since the second recess 13b is closed in a planar manner, it is easier to increase the strength of the container compared to the case where it is not. In the latter case (Figure 9(b)), the planar area for mounting the temperature sensor 17 can be increased compared to the former case.

[0032] 6. About the crystal vibrator The quartz crystal oscillator 11 described with reference to Figures 1 and 2 had a uniform thickness and a rectangular planar shape, but the shape of the quartz crystal oscillator is not limited to the above example. For example, as shown in Figure 10(A), the crystal diaphragm may have a so-called one-sided frame structure, having a vibrating part 11c with a thickness corresponding to the frequency and a support part 11d that is thicker than the vibrating part 11c. Alternatively, as shown in Figure 10(B), the crystal diaphragm may have a notch 11e between the vibrating part and the support part. Furthermore, as shown in Figure 10(C), the crystal diaphragm may have a through hole 11f between the vibrating part and the support part. The notch 11e and the through hole 11f may be provided in a crystal diaphragm with a uniform thickness, or in a crystal diaphragm with a one-sided frame structure as shown in Figure 10(A). [Explanation of Symbols]

[0033] 10, 30, 40: Crystal oscillator of the embodiment, 11: AT-cut quartz crystal vibrating piece 13: Container 13a: Recess for mounting quartz crystal (first recess) 13b: Recess for mounting temperature sensor (second recess) 13x: Main body 13y: Metal ring-shaped component 13ya: First side wall of the container 15: Base 15a: First wiring pattern 15b: Second wiring pattern 15c: Third wiring pattern 15d, 15e, 15f: Recessed part 15s: Protrusion 15x: Notch (C-chamfered section) 17: Temperature sensor 19: Lid component 21: Conductive adhesive

Claims

1. A piezoelectric device comprising: a container having a rectangular recess containing a piezoelectric vibrator; a rectangular piezoelectric vibrator cantilevered to the bottom surface of the recess via a base on the side of a first side wall corresponding to the first side of the recess; and a rectangular base, The base has a first wiring pattern on its first surface for connection to the piezoelectric vibrator, a second wiring pattern on its second surface opposite to the first surface for connection to the container, and a third wiring pattern on its side wall for connecting the first and second wiring patterns, Each of the first and second wiring patterns is provided with a recessed portion on at least the first side wall side of the base that recedes from the edge of the base toward the center, The piezoelectric device is characterized in that the third wiring pattern is provided on the side wall of the base that is located on the side wall opposite to the side wall facing the first side wall.

2. The piezoelectric device according to claim 1, characterized in that each of the first wiring pattern and the second wiring pattern further includes a recessed portion on the side of the base where the two side walls intersect with the side wall opposite the first side wall.

3. The piezoelectric device according to claim 1, characterized in that the base has notches at both ends of the side wall facing the first side wall.

4. The piezoelectric device according to claim 1, characterized in that the container comprises a ceramic body and a metal ring-shaped member connected to the body and forming the side wall of the recess.

5. The piezoelectric vibrator is a quartz crystal vibrator with a square planar shape and an AT cut, which is cantilevered to the base at two points along its first edge. The piezoelectric device according to claim 1, characterized in that the base is made of quartz, includes the same crystal axis as the crystal axis of the quartz along the two points of the quartz vibrator, and is connected and fixed to the quartz vibrator in such a way that its crystal axis coincides with that of the quartz vibrator.

6. The piezoelectric vibrator is a quartz crystal vibrator with a square planar shape and an AT cut, which is cantilevered to the base at two points along its first edge. The base is made of quartz, includes the same crystal axis as the crystal axis of the quartz along the two points of the quartz vibrator, and is connected and fixed to the quartz vibrator in such a way that its crystal axis coincides with that of the quartz vibrator. The piezoelectric device according to claim 1, characterized in that the container comprises a ceramic body and a metal ring-shaped member connected to the body and forming the side wall of the recess.

7. The piezoelectric vibrator is a quartz crystal vibrator with a square planar shape and an AT cut, which is cantilevered to the base at two points along its first edge. The piezoelectric device according to claim 1, characterized in that the base is made of quartz, has notches at both ends of the side wall facing the first side wall, has protrusions at both ends of the side wall on the side wall where the third wiring pattern is provided, includes the same crystal axis as the crystal axis of the quartz along the two points of the quartz vibrator, and is connected and fixed to the quartz vibrator in such a relationship that its crystal axis coincides with the quartz vibrator.

8. The piezoelectric vibrator is a quartz crystal vibrator with a square planar shape and an AT cut, which is cantilevered to the base at two points along its first edge. The piezoelectric device according to claim 1, characterized in that the base is made of quartz, has a thickness selected from 30 to 60 μm, includes the same crystal axis as the crystal axis of the quartz along the two points of the quartz vibrator, is connected and fixed to the quartz vibrator in such a way that its crystal axis coincides with the quartz vibrator, and its length is such that it does not reach the excitation electrode provided on the quartz vibrator.

9. The piezoelectric vibrator is a quartz crystal vibrator with a square planar shape and an AT cut, which is cantilevered to the base at two points along its first edge. The base is made of quartz, has a thickness selected from 30 to 60 μm, includes the same crystal axis as the quartz crystal axis along the two points of the quartz vibrator, is connected and fixed to the quartz vibrator in such a way that its crystal axis coincides with the quartz vibrator, and its length is such that it does not reach the excitation electrode provided on the quartz vibrator. The piezoelectric device according to claim 1, characterized in that the container comprises a ceramic body and a metal ring-shaped member connected to the body and forming the side wall of the recess.

10. The piezoelectric device according to any one of claims 5 to 9, further comprising a second recess containing a temperature sensor and the temperature sensor contained in the second recess.

11. The piezoelectric device according to claim 10, characterized in that the piezoelectric device is a piezoelectric device with a built-in temperature sensor in a single-chamber structure or a piezoelectric device with a built-in temperature sensor in an H-shaped structure.

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