Quartz oscillator with built-in temperature sensor

Abstract

To provide a crystal vibrator with a built-in temperature sensor having a novel structure that can be downsized and can enhance the frequency accuracy more than that of a conventional crystal vibrator.SOLUTION: A crystal resonator 10 includes a container 11, a crystal resonator element 13 and a temperature sensor 15 mounted on the container, a lid member 17 connected to the container and sealing the crystal resonator element and the temperature sensor, and a pedestal 19 made of crystal. The temperature sensors are provided on the 11c of the first main surface of the vessel. A quartz-made pedestal having a height h1 higher than the height h2 of the temperature sensors is provided in a region other than the region where the temperature sensors of the first main surface are provided. A part of the crystal vibration piece 13 is positioned above the temperature sensor, and the other part is connected and fixed to a pedestal 19 made of crystal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a quartz crystal unit having a built-in temperature sensor such as a thermistor. [Background technology]

[0002] In recent years, crystal units with built-in temperature sensors, which have an AT-cut crystal resonator element and a temperature sensor built into a single container, have become popular. This is because the external electronic device (chipset) designed for use with this unit compensates for the oscillation frequency of the crystal resonator element based on the temperature information detected by the temperature sensor, allowing the desired frequency to be obtained with greater precision. Typical examples of crystal units with built-in temperature sensors include those with a single-chamber structure and those with an H-shaped structure. The former has a crystal resonator element and a temperature sensor mounted in a single chamber and hermetically sealed (see, for example, paragraph 75, Figure 7, etc., of Patent Document 1). The latter has a first chamber mounting a crystal resonator element and a second chamber mounting a temperature sensor stacked back to back, with the first chamber being hermetically sealed (see, for example, the abstract, Figure 1, etc., of Patent Document 2).

[0003] In a single-chamber structure, the quartz crystal resonator and temperature sensor are mounted in the same space, so the thermal effects on the quartz crystal resonator and temperature sensor are similar compared to an H-shaped structure, making it easier to improve temperature compensation accuracy. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-70552 [Patent Document 2] Japanese Patent Publication No. 2022-140662 Summary of the Invention [Problem to be solved by the invention]

[0005] Demand for miniaturization is also increasing for single-chamber structures. To meet this demand, the quartz crystal resonator element and temperature sensor are arranged three-dimensionally in the vertical direction to reduce the surface area. For example, in the example shown in Figure 7 of Patent Document 1, a dedicated recess for mounting a temperature sensor is provided in the container for the quartz crystal resonator, and the temperature sensor is mounted in this recess, with the quartz crystal resonator element placed above it. This container, including the recess for the temperature sensor, is made of a ceramic package (see, for example, paragraph 75 of Patent Document 1). On the other hand, there is also a demand for further improvement in frequency accuracy for crystal resonators with built-in temperature sensors, and therefore it is desirable to be able to satisfy both the requirements for miniaturization and improved frequency accuracy. This application has been filed in consideration of the above points, and therefore, an object of this application is to provide a crystal unit with a built-in temperature sensor that has a novel structure that can be made smaller and has improved frequency accuracy compared to conventional units. [Means for solving the problem]

[0006] In order to achieve this object, according to the present invention, there is provided a crystal unit with a built-in temperature sensor, which includes a container, a crystal resonator element and a temperature sensor mounted in the container, and a cover member connected to the container and sealing the crystal resonator element and the temperature sensor, The temperature sensor is provided on a first main surface of the container, a quartz crystal base having a height greater than that of the temperature sensor is provided in an area of ​​the first main surface other than the area where the temperature sensor is provided, The quartz crystal resonator element has a portion located above the temperature sensor and another portion connected and fixed to the quartz crystal base.

[0007] In implementing this invention, the quartz crystal base is preferably rectangular. Many of the quartz crystal vibrating pieces mass-produced in recent years are rectangular in plan view and are often fixed to a container at two points along one of their short sides. In such cases, a rectangular quartz crystal base has the advantage of being easily positioned near one of the short sides of the rectangular quartz crystal vibrating piece in plan view, without contacting the temperature sensor. Furthermore, the quartz crystal vibrating piece can be cantilevered without contacting the temperature sensor.

[0008] In implementing this invention, the quartz crystal base is preferably L-shaped in plan view, consisting of a first linear portion and a second linear portion that intersects and continues thereto. However, as will be described in detail later with reference to FIG. 2, the first linear portion and the second linear portion should be set to predetermined widths and lengths that take into account the relationship with the temperature sensor and the quartz crystal resonator element. Specifically, if the quartz crystal resonator element is rectangular in plan view, the length of the first linear portion should be at least half the length of the long side of the rectangular quartz crystal resonator element, preferably at least the length of the long side of the quartz crystal resonator element, and the width of the first linear portion should be wide enough to avoid contact with the temperature sensor. On the other hand, the length of the second linear portion should be equal to or longer than the short side of the rectangular quartz crystal resonator element, but should not contact the container. The width of the second linear portion should be wide enough to avoid contact with the temperature sensor and to support the quartz crystal resonator element in a cantilevered manner. This allows the quartz crystal resonator element to be connected and fixed to the second linear portion of the L-shaped quartz crystal base, while the first linear portion of the L-shaped quartz crystal base acts as a support to prevent the tip of the quartz crystal resonator element from dropping. Furthermore, the L-shaped base prevents the base from tipping over, allowing it to be stably mounted on the first main surface of the container.

[0009] In carrying out this invention, the container can be made of ceramic, glass, quartz, resin (glass epoxy), metal, etc. However, because ceramic has a proven track record in mass production, a ceramic container is preferred for use in the present invention. Even when a ceramic container is used, in the present invention, the quartz base is present between the ceramic and the quartz vibrating piece, thereby mitigating the difference in thermal expansion coefficients between the ceramic and quartz. Furthermore, since the space for mounting the temperature sensor can be secured by the quartz base itself, which is higher than the temperature sensor, the ceramic container can have a simple structure without a recess for the temperature sensor, which also reduces the cost of the ceramic container. The container can also be a quartz container made by metal-to-metal bonding of multiple quartz crystals. For example, it may be a quartz container such as that described in JP 2021-179882 A, which is owned by the same applicant. When the container is made of quartz crystal, an all-quartz crystal resonator with a built-in temperature sensor can be realized, with both the container and the base made of quartz crystal. Furthermore, because quartz crystal can be polished to the desired thickness with high precision, using a quartz crystal container makes it possible to realize a thin, highly precise crystal resonator with a built-in temperature sensor. [Effects of the Invention]

[0010] The crystal unit with an integrated temperature sensor of this invention has a crystal base that is taller than the temperature sensor and is provided on the first main surface of the container in an area other than where the temperature sensor is provided. This crystal base therefore acts as a spacer member that ensures vertical space when the temperature sensor is mounted in the container, and also acts as a stress relief member that relieves stress that occurs due to differences in the thermal expansion coefficients of the container and the crystal vibrating piece, the effects of the adhesive that bonds the container and the crystal vibrating piece, etc. Therefore, according to the present invention, by arranging the temperature sensor and the quartz crystal resonator piece three-dimensionally in the vertical direction, the planar area of ​​the quartz crystal resonator can be reduced, and the frequency accuracy can be improved by reducing the stress acting on the quartz crystal resonator piece. As a result, it is possible to provide a crystal unit with a built-in temperature sensor that has a novel structure that can be made smaller and has improved frequency accuracy compared to conventional units. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating a crystal unit 10 with a built-in temperature sensor according to a first embodiment. [Figure 2] 10A and 10B are diagrams illustrating a crystal unit 30 with a built-in temperature sensor according to a second embodiment. [Figure 3] 10A and 10B are diagrams illustrating a preferred combination of a quartz crystal vibrating piece and a quartz crystal base. [Figure 4] FIG. 10 is a diagram illustrating another example of a container used in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of a crystal resonator with a built-in temperature sensor according to the present invention will be described with reference to the drawings. Note that the drawings used for the description are merely schematic illustrations to allow for an understanding of the present invention. In addition, in the drawings used for the description, similar components are designated by the same reference numerals, and their description may be omitted. Furthermore, the material configurations, numerical examples, etc. described in the following description are merely preferred examples within the scope of the present invention. Therefore, the present invention is not limited to the following embodiments.

[0013] 1. First Embodiment 1A and 1B are diagrams illustrating a crystal unit 10 with an internal temperature sensor (hereinafter sometimes abbreviated as crystal unit 10) according to a first embodiment. In particular, FIG. 1A is a plan view, FIG. 1B is a cross-sectional view taken along line PP in FIG. 1A, and FIG. 1C is a bottom view. However, FIG. 1A shows a state in which the cover member 17 shown in FIG. 1B has been removed.

[0014] The quartz crystal unit 10 includes a container 11, a quartz crystal vibrating piece 13 and a temperature sensor 15 mounted in the container 11, a lid member 17 connected to the container 11 and sealing the quartz crystal vibrating piece 13 and the temperature sensor 15, and a quartz crystal base 19, which is one of the features of the present invention. Each of the components will be described in detail below.

[0015] In this embodiment, the container 11 includes a recess 11a that houses the quartz crystal vibrating piece 13 and the temperature sensor 15, and a bank portion 11b that forms the recess 11a. In this first embodiment, the bottom surface of the recess 11a corresponds to the first main surface 11c of the container 11 in the present invention. The container 11 and the recess 11a each have a substantially rectangular shape in a plan view. Furthermore, the container 11 has two first pads 11d for mounting a crystal base 19 along a direction parallel to the short side of the recess 11a on the bottom surface of the recess 11a, i.e., the first main surface, in an area close to one short side of the recess 11a. The container 11 also has two second pads 11e for mounting a temperature sensor 15 in an area away from the first pads 11d on the bottom surface of the recess 11a. In this case, the arrangement direction of the first pads 11d and the arrangement direction of the second pads 11e are perpendicular to each other. Furthermore, external connection terminals 11f for connecting to an external electronic device (not shown) are provided, for example, near the four corners of the outer bottom surface of the container 11. The first pads 11d, the second pads 11e, and the external connection terminals 11f are connected in a predetermined relationship by any wiring (not shown), such as via wiring or castellation wiring. In this case, this container 11 is made of a ceramic package. However, while the conventional ceramic package shown in Patent Document 1 required a dedicated recess for incorporating the temperature sensor, the package of the present invention can ensure the vertical mounting space for the temperature sensor with a quartz base 19 of a predetermined height, eliminating the need for a dedicated recess for incorporating the temperature sensor. This makes it easier to reduce the cost of the ceramic package. Furthermore, since there is no need to provide a dedicated recess for incorporating the temperature sensor, the area for mounting the temperature sensor can be expanded.

[0016] In this example, the quartz crystal vibrating piece 13 is an AT-cut quartz crystal vibrating piece having an AT-cut quartz crystal piece 13a and excitation electrodes 13b provided on the front and back of the quartz crystal vibrating piece, and is rectangular in shape in a plan view. The mounting position of the quartz crystal vibrating piece 13 will be described later. The temperature sensor 15 has a height h1 (see FIG. 1(A)). In this embodiment, the temperature sensor 15 is configured as a rectangular parallelepiped thermistor. The temperature sensor 15 has connection terminals 15a at both longitudinal ends, and these connection terminals 15a are connected to second pads 11e on the bottom surface of the recess 11a of the container 11 with a conductive adhesive 21. The height h1 of the temperature sensor 15 is the height after the temperature sensor 15 has been mounted in the container 11. The height h1 of the temperature sensor 15 is important in relation to the height h2 of the crystal base 19, which will be described later, and will be described again when describing the crystal base 19, which will be described later. The lid member 17 cooperates with the container 11 to hermetically seal the quartz crystal resonator element 13, the temperature sensor 15, and the quartz crystal base 19. The lid member 17 can be any type that suits the sealing method of the quartz crystal resonator 10. For example, if the sealing method is a seam sealing method, as shown in FIG. 1(B), a metal seam ring 11g is provided on the top surface of the bank portion 11b of the container 11, and the lid member 17 is a plate-like member made of Kovar or the like that can be welded to the seam ring 11g.

[0017] The quartz crystal pedestal 19 has a height h2 (h2>h1) that is greater than the height h1 of the temperature sensor 15. In this embodiment, the quartz crystal pedestal 19 is rectangular, with a long side dimension α (see FIG. 1(A)) that is approximately equal to or greater than the short side of the quartz crystal vibrating piece 13 and shorter than the short side of the recess 11a of the container 11. The short side dimension β is an arbitrary length that does not contact the temperature sensor 15, for example, a length that does not reach the excitation electrode 13b. The height h2 of the quartz crystal pedestal 19 is the height after the quartz crystal pedestal 19 is mounted on the first main surface 11c of the container 11. Therefore, the top surface of the quartz crystal pedestal 19 is higher than the top surface of the temperature sensor 15.

[0018] The difference Δh (=h2-h1) between the height h2 of the quartz crystal base 19 and the height h1 of the temperature sensor 15 is determined by taking into consideration factors such as whether contact between the quartz crystal vibrating piece 13 and the temperature sensor 15 can be avoided, whether the product height of the quartz crystal vibrating piece 10 is not exceeded, whether the tip of the quartz crystal vibrating piece 13 moves due to external impacts, and whether there is variation in the mounting of the quartz crystal vibrating piece and the temperature sensor. Δh is preferably, for example, 10 to 40 μm, more preferably 15 to 25 μm, and even more preferably 10 to 20 μm, although this is not limited thereto. The crystal base 19 also has wiring 19a made of a metal film or the like on its top, side, and bottom surfaces. The wiring 19a cooperates with a conductive adhesive 21, which will be described later, to enable electrical connection between the crystal vibrating piece 13 and the first pad 11d of the container 11.

[0019] Crystal base 19 is mounted in recess 11a of container 11 close to one of the short sides of recess 11a, with the long side of base 19 parallel to the short side of recess 11a. First pad 11d of container 11 and a bottom portion of wiring 19a of base 19 are connected and fixed with conductive adhesive 21. A portion of the quartz crystal vibrating piece 13 is positioned above the temperature sensor 15, and another portion is connected and fixed to the quartz crystal base 19 with conductive adhesive 21. Therefore, the quartz crystal vibrating piece 13 is connected and fixed in a cantilevered state to the top surface of the quartz crystal base 19, in a position that almost covers the temperature sensor 15 from above.

[0020] This quartz crystal resonator 10 has a predetermined quartz crystal base 19 in a predetermined position, which ensures space for three-dimensionally mounting the temperature sensor 15 below the quartz crystal resonator piece 13 and reduces the effects of stress on the quartz crystal resonator piece 13.

[0021] 2. Second embodiment 2A and 2B are diagrams for explaining a crystal unit 30 with an internal temperature sensor (hereinafter sometimes abbreviated as crystal unit 30) according to a second embodiment. In particular, Fig. 2A is a plan view thereof, Fig. 1B is a perspective view of a crystal base 31 according to the second embodiment, and Fig. 2C is a cross-sectional view taken along line PP in Fig. 2A. The crystal unit 30 of the second embodiment differs from the crystal unit 10 of the first embodiment in the planar shape of the crystal base.

[0022] 2, the quartz crystal base 31 provided on the quartz crystal unit 30 is composed of a first linear portion L1 and a second linear portion L2 that intersects with the first linear portion L1 (orthogonal in this example) and continues thereto, forming an L-shape in a plan view with a height h1. This height h1 is measured after the unit is mounted in a container, as in the first embodiment. The dimensions of the first linear portion L1 and second linear portion L2 of the L-shaped quartz crystal base 31 are selected so as not to come into contact with the temperature sensor 15. When the quartz crystal vibrating piece 13 is rectangular in plan view, the length of the first linear portion L1 is at least half the length of the long side of the quartz crystal vibrating piece 13, or in the example of FIG. 2 , the length is at least the length of the long side of the quartz crystal vibrating piece. Furthermore, the width W2 of the first linear portion L1 is sized to extend below the quartz crystal vibrating piece 13 without contacting the temperature sensor 15. The second linear portion L2 of the base 31 is longer than the short side of the quartz crystal vibrating piece 13 and is long enough so as not to come into contact with the container 11. The width W2 of the second linear portion L2 of the base 31 is long enough to cantilever the quartz crystal vibrating piece 13 without contacting the temperature sensor 15.

[0023] The crystal unit 30 of the second embodiment also includes a base 31 made of a specified quartz crystal, which, like the first embodiment, ensures space for three-dimensionally mounting the temperature sensor 15 below the crystal vibrating piece 13 and reduces the effects of stress on the crystal vibrating piece 13. Furthermore, in the case of this crystal unit 30, the first linear portion L1 of the L-shape is located below the crystal vibrating piece 13, so even if the tip of the crystal vibrating piece 13 bows, the first linear portion of the base 31 prevents the tip from bowing any further.

[0024] 3. Relationship between the crystal blank and the crystal base Next, with reference to FIG. 3, a preferred combination of a quartz crystal vibrating piece and a quartz crystal base will be described. 3(A) is a plan view of an AT-cut quartz crystal vibrating piece 13, where two points fixed to a quartz crystal base 19 are aligned with the Z' axis of the quartz crystal. Here, the Z' axis refers to an axis that is offset from the Z axis of the quartz crystal due to the cutting angle of the AT cut. 3(A), the quartz crystal base 19x is a base made of an AT-cut quartz crystal plate, and is preferably positioned so that its axial direction is the same as that of the quartz crystal vibrating piece 13. In other words, the quartz crystal vibrating piece 13 and the quartz crystal base 19x are preferably positioned so that the X, Y', and Z' axes of the quartz crystal in the quartz crystal vibrating piece 13 are aligned with the X, Y', and Z' axes of the quartz crystal in the quartz crystal base 19x. Note that the alignment of the axes may mean that the cutting angle is slightly misaligned, for example, by several minutes, within the range that is classified as an AT cut.

[0025] FIG. 3(B) is a plan view showing an AT-cut quartz crystal vibrating piece 13, in which two points fixed to a quartz crystal base 19 are aligned with the X-axis of the quartz crystal. 3(B), there are two types of preferred quartz crystal base 19. The first quartz crystal base 19y is a base made of an AT-plate quartz crystal. However, the quartz crystal base 19y has a difference in that its longitudinal direction is aligned with the X-axis of the quartz crystal and its lateral direction is aligned with the Z'-axis of the quartz crystal. On the other hand, the second quartz crystal base 19z is a base made of a Z-plate of quartz crystal. In this case, the base 19y is positioned so that the direction along the X-axis of the quartz crystal on the Z-plate base is aligned with the X-axis of the quartz crystal vibrating piece 13. It is preferable to align the crystal axes of the quartz crystal vibrating piece 13 and the quartz crystal base 19, as this increases the stress relaxation effect of the quartz crystal base compared to when this is not the case.

[0026] Although several embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above embodiment, a ceramic container was used as the container 11, but the container may also be made of quartz. Specifically, the present invention can be applied to a quartz container configured by bonding one or more quartz plates together by metal-to-metal bonding and providing predetermined wiring, and a quartz container configured by bonding one or more quartz plates together with a ring-shaped quartz plate forming a bank portion by metal-to-metal bonding and providing predetermined wiring. Specifically, a temperature sensor and a quartz base according to the present invention may be mounted on a container such as that disclosed in Figures 1 and 2 of Japanese Patent Laid-Open No. 2022-145456, which is owned by the applicant. Furthermore, as shown in FIG. 4, the present invention can also be applied to a temperature sensor-embedded crystal unit 40 in which a sealed space is formed by a flat container 41 (substrate 41) and a cap-shaped lid member 43 having a recess that covers the crystal vibrating piece 13, etc., even if a crystal base is used. [Explanation of symbols]

[0027] 10: Crystal unit with built-in temperature sensor according to the first embodiment 11: Container 11c: First side 13: Crystal vibrating piece 15: Temperature sensor 17: Lid 19: Crystal base 19x, 19y, 19z: Crystal base with consideration for crystal axis h1: Height of the temperature sensor h2: Height of the crystal base 30: Crystal unit with built-in temperature sensor according to the second embodiment 31: Crystal base 40: Crystal oscillator with built-in temperature sensor according to another embodiment 41: Container 43: Lid member

Claims

1. A crystal unit with a built-in temperature sensor includes a container, a crystal resonator element and a temperature sensor mounted in the container, and a lid member connected to the container and sealing the crystal resonator element and the temperature sensor, the temperature sensor is provided on a first main surface of the container; a quartz crystal base having a height greater than that of the temperature sensor is provided in an area of ​​the first main surface other than the area where the temperature sensor is provided, A crystal unit with a built-in temperature sensor, characterized in that a portion of the crystal resonator element is positioned above the temperature sensor, and another portion is connected and fixed to the crystal base.

2. the container has a rectangular shape in a plan view and includes a recess having a rectangular shape in a plan view and containing the crystal vibrating piece and the temperature sensor; the crystal base is rectangular and is mounted in the recess in the vicinity of one short side of the recess so that the long side of the rectangular parallelepiped is parallel to the short side; The crystal vibrating piece has a rectangular shape in a plan view, and one short side of the crystal vibrating piece is connected and fixed to the crystal base in a cantilevered manner.

2. The crystal unit with a built-in temperature sensor according to claim 1, wherein the temperature sensor is mounted below the crystal resonator element.

3. the container has a rectangular shape in a plan view and includes a recess having a rectangular shape in a plan view and containing the crystal vibrating piece and the temperature sensor; the quartz crystal base is an L-shaped base in plan view, having a first linear portion and a second linear portion that intersects and continues to the first linear portion, and the first linear portion is an L-shaped base in plan view, having a shape that extends below the quartz crystal vibrating piece without contacting the temperature sensor; 2. The crystal unit with a built-in temperature sensor according to claim 1, wherein the crystal resonator element has a rectangular shape in a plan view, and one of its short sides is connected and fixed to the second linear portion of the crystal base in a cantilevered manner.

4. The temperature sensor built-in crystal unit according to claim 1, characterized in that, when the height of the temperature sensor is h1, the height of the crystal base is h2, and the difference between the two is Δh = h2 - h1, Δt is 10 to 40 μm.

5. The quartz crystal resonator element is an AT-cut quartz crystal resonator element, The quartz crystal base is an AT-cut quartz crystal piece or a Z-cut quartz crystal piece, 2. The temperature sensor-embedded quartz crystal unit according to claim 1, wherein the quartz crystal resonator element and the quartz crystal base are mounted in the container with at least a portion of the crystal axes of the respective quartz crystals aligned.

6. The quartz crystal vibrating piece is an AT-cut quartz crystal vibrating piece having a rectangular shape in a plan view, The quartz crystal base is an AT-cut quartz crystal piece or a Z-cut quartz crystal piece, The crystal vibrating piece is connected and fixed to the crystal base at one short side thereof, 2. The temperature sensor-embedded quartz crystal unit according to claim 1, wherein the quartz crystal resonator element and the quartz crystal base are mounted in the container with the crystal axes of the quartz crystal aligned in the direction along one of the short sides.

7. 7. The crystal unit with a built-in temperature sensor according to claim 1, wherein the container is made of ceramic.

8. The temperature sensor-embedded quartz crystal unit according to any one of claims 1 to 6, characterized in that the container is a ceramic container having a single recess that houses the quartz crystal resonator piece and the temperature sensor.

Images