JP2020123816A - Vibration element pedestal, vibrator, and oscillator - Google Patents

Abstract

To provide a vibration element pedestal, a vibrator, and an oscillator that can suppress the influence of external vibration to improve vibration resistance and improve phase noise characteristics.SOLUTION: A vibration element pedestal includes a mounting portion 11 that mounts a crystal piece 2, two connecting portions 14a provided in parallel with each of the opposing short sides of the mounting portion 11 and connected to electrodes formed in a package 3, a first coupling portion in which a coupling portion 13 couples the mounting portion 11 and the connecting portion 14a couples a first enclosing portion surrounding the mounting portion 11 and a portion 13a forming a short side of the mounting portion 11 and a short side of the first enclosing portion, a second enclosing portion that encloses the first enclosing portion, and a second coupling portion in which the coupling portion 13 couples the corner portion of the first enclosing portion and the corner portion of the second enclosing portion, and the connecting portion 14a is provided in a portion 12c that forms the short side of the second enclosing portion, and there are also provided a vibrator and an oscillator using the vibration element pedestal.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pedestal on which a vibrating element is mounted, and more particularly, to a pedestal, a vibrator, and an oscillator for a vibrating element that can improve resistance to external vibration and have good phase noise characteristics.

[Conventional technology]
In a conventional crystal resonator, a structure using a pedestal mainly made of crystal (crystal pedestal) is known as a structure for suppressing the influence on the crystal piece from the package and the outside of the package.
Further, there is a crystal oscillator in which the package has an H structure in which concave portions are formed on the front and back surfaces, a crystal piece and a crystal pedestal are mounted on the front side, and an IC (Integrated Circuit) of an oscillation circuit is mounted on the back surface.
There is a temperature-compensated crystal oscillator (TCXO: Temperature Compensated Crystal Oscillator) in which a temperature compensation circuit is provided on the front surface or the back surface of the package.

[Related technology]
As related prior arts, Japanese Patent No. 3017750 “Crystal resonator” (Patent Document 1), Japanese Patent No. 4715252 “Piezoelectric vibrator” (Patent Document 2), Japanese Patent Laid-Open No. 2013-098678 “Crystal vibration” Child” (Patent Document 3).

In Patent Document 1, a recess is formed in a position where the vibrating crystal piece is mounted on a holding crystal plate, and the vibrating crystal piece is surely excited in a gap formed by the recess, so that heat in the longitudinal direction of the vibrating crystal piece is increased. A crystal unit that does not generate stress due to is shown.

Patent Document 2 discloses a piezoelectric vibrator including a spring portion having a gap in order to reduce the influence of thermal expansion in the substrate.
Patent Document 3 discloses a crystal resonator configured to prevent deformation of the crystal piece due to temperature change and obtain good frequency-temperature characteristics.

Japanese Patent No. 3017750 Japanese Patent No. 4715252 JP, 2013-098678, A

However, in the crystal pedestal of the conventional crystal oscillator or crystal oscillator, there is a problem that external vibration affects the crystal piece, and the vibration deteriorates the phase noise characteristic.

In addition, in Patent Documents 1 to 3, a mounting portion that mounts a crystal piece and a connecting portion that connects to a substrate such as a ceramic are connected by a connecting portion, and a plurality of gaps are formed so as to surround the mounting portion in the connecting portion. There is no description about the configuration provided with.

The present invention has been made in view of the above circumstances, and provides a pedestal for a vibrating element, a vibrator, and an oscillator that suppresses the influence of vibration from the outside to improve the vibration resistance characteristics and can improve the phase noise characteristics. The purpose is to

The present invention for solving the problems of the above-mentioned conventional example is a pedestal for a vibrating element on which a vibrating element is mounted, and a mounting portion on which the vibrating element is mounted, and the mounting portion provided in parallel to each short side. And a connecting portion connecting the mounting portion and the connecting portion, the connecting portion including a first enclosure portion surrounding the mounting portion, and a mounting portion. First connecting portion that connects the short side of the first surrounding portion and the short side of the first surrounding portion, a second surrounding portion surrounding the first surrounding portion, a corner portion of the first surrounding portion, and a second surrounding portion A second connecting portion that connects the corners of the portion, and the connecting portion is provided on the short side of the second surrounding portion.

The present invention is a pedestal for a vibrating element on which a vibrating element is mounted, the mounting portion on which the vibrating element is mounted, and the electrodes provided in the mounting portion in parallel to each long side and connected to electrodes formed in a package. And a connecting portion that connects the mounting portion and the connecting portion, the connecting portion includes a first enclosing portion that surrounds the mounting portion, a short side of the mounting portion, and a short portion of the first enclosing portion. A first connecting portion connecting the sides, a second surrounding portion surrounding the first surrounding portion, and a second coupling connecting the corner portion of the first surrounding portion and the corner portion of the second surrounding portion. And a connection portion is provided on a long side of the second enclosing portion.

The present invention is characterized in that, in the pedestal, the mounting portion, the connecting portion, and the connecting portion have the same thickness.

According to the present invention, in the above-described pedestal, a first gap portion is provided between a long side of the mounting portion and a long side of the first enclosing portion, and the long side of the first enclosing portion and the length of the second enclosing portion are long. A second gap portion is provided between the side and the side, and a third gap portion is provided between the short side of the first surrounding portion and the short side of the second surrounding portion.

The present invention is characterized in that, in the vibrator, the vibrating element is mounted on the pedestal and is installed in a step portion formed so as to project from the bottom surface of the concave portion of the package surface.

The present invention is characterized in that, in the oscillator, the oscillating element is mounted on the pedestal, the oscillating element is installed on a step portion formed so as to project from the bottom surface of the package surface recess, and the oscillation circuit is mounted on the bottom surface of the package surface recess. ..

The present invention is characterized in that, in the oscillator, the oscillating element is mounted on the pedestal, the oscillating circuit is mounted on the step portion formed so as to project from the bottom surface of the package front surface recess, and the oscillating circuit is mounted on the back surface recess of the package.

According to the present invention, there is provided a pedestal for a vibrating element on which a vibrating element is mounted, the mounting portion on which the vibrating element is mounted, and an electrode formed in the package in parallel with each short side of the mounting portion. And a connecting portion that connects the mounting portion and the connecting portion, the connecting portion including a first enclosing portion surrounding the mounting portion, a short side of the mounting portion, and a first enclosing portion. A second connecting portion that connects the short side of the first connecting portion, a second connecting portion that surrounds the first surrounding portion, and a second connecting portion that connects the corner portion of the first surrounding portion and the corner portion of the second surrounding portion. Since the connecting part is a pedestal provided on the short side of the second surrounding part, even if external vibration is transmitted to the connecting part, it is absorbed by the connecting part. This has the effect of reducing the influence on the mounting part.

According to the present invention, there is provided a pedestal for a vibrating element on which a vibrating element is mounted, the mounting section on which the vibrating element is mounted, and an electrode provided in the mounting section in parallel with each long side and formed in a package. And a connecting portion that connects the mounting portion and the connecting portion, the connecting portion including a first enclosing portion surrounding the mounting portion, a short side of the mounting portion, and a first enclosing portion. A second connecting portion that connects the short side of the first connecting portion, a second connecting portion that surrounds the first surrounding portion, and a second connecting portion that connects the corner portion of the first surrounding portion and the corner portion of the second surrounding portion. Since the connecting portion is a pedestal provided on the long side of the second surrounding portion, even if vibration from the outside is transmitted to the connecting portion, it is absorbed by the connecting portion. This has the effect of reducing the influence on the mounting part.

It is a plane explanatory view of a pedestal. It is a side surface explanatory view of a main pedestal. It is a plane explanatory view of another base.

Embodiments of the present invention will be described with reference to the drawings.
[Outline of Embodiment]
A pedestal (main pedestal) according to an embodiment of the present invention is an electrode formed in a package in parallel with a mounting portion on which a vibrating element such as a crystal element is mounted and each of short sides facing each other of the mounting portion. And a connecting portion that connects the mounting portion and the connecting portion, the connecting portion including a first enclosing portion surrounding the mounting portion, a short side of the mounting portion, and a first enclosing portion. A second connecting portion that connects the short side of the first connecting portion, a second connecting portion that surrounds the first surrounding portion, and a second connecting portion that connects the corner portion of the first surrounding portion and the corner portion of the second surrounding portion. And the connecting portion is provided on the short side of the second surrounding portion, so that even if external vibration is transmitted to the connecting portion, the connecting portion absorbs the vibration. Therefore, the influence on the mounting portion can be reduced and the phase noise characteristic can be improved.

Further, another pedestal (another pedestal) according to the embodiment of the present invention is provided in parallel with each of a mounting portion on which a vibrating element such as a crystal element is mounted and a long side facing the mounting portion. And a connecting portion that connects the mounting portion and the connecting portion, the connecting portion including a first enclosing portion surrounding the mounting portion, and a short side of the mounting portion. A first connecting portion that connects the short side of the first enclosing portion, a second enclosing portion that encloses the first enclosing portion, a corner portion of the first enclosing portion, and a corner portion of the second enclosing portion. And a second connecting portion for connecting the second connecting portion, and the connecting portion is provided on the long side of the second enclosing portion. Therefore, even if external vibration is transmitted to the connecting portion. The phase noise characteristic can be improved by reducing the influence on the mounting portion by absorbing it at the connecting portion.

Further, the vibrator (main vibrator) according to the embodiment of the present invention is one in which a vibrating element is mounted on the main base, and the main base is installed in a package having a recess.
Further, the oscillator according to the embodiment of the present invention (the present oscillator) has an oscillator circuit mounted in the recess on the back surface of the package of the present oscillator.

[Main pedestal: Figures 1 and 2]
Next, a pedestal (main pedestal) according to the embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view of the main pedestal, and FIG. 2 is a side view of the main pedestal. Note that FIG. 1 shows a state where the vibrating element (crystal element) 2 is mounted, and in FIG. 2, the package 3 is shown in a cross section for easy understanding.
As shown in FIG. 1, the main pedestal 1 includes a rectangular mounting portion 11, a connecting portion 14a arranged in parallel with a short side of the mounting portion 11, and a connecting portion 13a connecting the mounting portion 11 and the connecting portion 14a. 13d (13a to 13d may be collectively referred to as a connecting portion 13).

The crystal piece 2 is mounted on the mounting portion 11, and its four corners are fixed with a conductive adhesive.
Electrode patterns 10a and 10b that are connected to the excitation electrodes of the crystal element 2 are formed on the mounting portion 11, and the metal electrode patterns are drawn out to the connecting portion 13 and connected to the connecting portion 14a. The electrode pattern will be described later.

The connecting portion 13 includes a first surrounding portion surrounding the mounting portion 11 and a second surrounding portion surrounding the first surrounding portion, and the mounting portion 11 and the first surrounding portion are connected by a short side. The first and second enclosures are connected at the four corners.

The first surrounding portion includes a portion 13a forming a short side and a portion 13b forming a long side, and a central portion of the short side of the mounting portion 11 and a central portion of the portion 13a forming the short side are connected to each other. They are connected by (first connecting portion). Therefore, in FIG. 1, gaps 12 a are provided above and below the long side of the mounting portion 11. The gaps 12a to 12c may be referred to as the gap 12. The gap 12 penetrates from the front surface to the back surface of the main pedestal.

The second surrounding portion includes a portion 13c forming the short side and a portion 13d forming the long side, and the outside of the corner portion of the first surrounding portion and the inside of the corner portion of the second surrounding portion are connected. They are connected by a part (second connecting part). Therefore, in FIG. 1, a gap 12b is provided between the long side of the first enclosing portion and the long side of the second enclosing portion, and the short side of the first enclosing portion and the short side of the second enclosing portion are short. A gap 12c is provided between the side and the side.

As shown in FIG. 1, the connecting portion 14a has a shape that protrudes outward at the center of the portion 13c that forms the short side of the second enclosing portion of the connecting portion 14, and the protruding portion is the ceramic package. It is mounted in contact with the protrusion 3a.
The projecting portion 3a has a structure that projects upward from the bottom surface of the package having an inner concave shape, and has electrodes formed thereon, and is bonded to the connecting portion 14a with a conductive adhesive 5 or solder. Details of the structure of the package will be described later.

The main pedestal 1 is made of, for example, a resin such as heat-resistant plastic, glass, or an insulating material such as metal having a surface coated with an insulating film.
Further, the main pedestal 1 may be formed of a crystal similar to the vibrating piece (crystal piece) 2 (the same AT cut or Z plate as the crystal piece 2). In that case, the thermal expansion coefficients of the pedestal 1 and the crystal piece 2 are substantially equal to each other, and stress due to temperature change does not occur.

Further, on the main pedestal 1, electrode patterns 10a and 10b connected to the excitation electrodes of the crystal piece 2 are formed. The electrode patterns 10a and 10b are formed of a thin film of metal such as gold.
As shown in FIG. 1, the electrode pattern 10a has a rectangular pattern in which the conductive adhesive 4 is applied to the lower left portion of the mounting portion 11 that overlaps with the crystal piece 2, and the square pattern is connected thereto at the first connecting portion. The left side short side of the second surrounding portion is formed by being drawn out to the lower left corner of the second surrounding portion at the second connecting portion via the portion 13a forming the left side short side of the first surrounding portion. The connecting portion 14a formed in the portion 13c is formed.

As shown in FIG. 1, the electrode pattern 10b has a rectangular pattern in which the conductive adhesive 4 is applied to the upper right portion of the mounting portion 11 which overlaps with the crystal piece 2, and the square pattern is connected thereto at the first connecting portion. It is pulled out to the upper right corner of the second enclosure by the second connecting portion via the portion 13a that constitutes the right short side of the first enclosure, and forms the right short side of the second enclosure. The connecting portion 14a formed in the portion 13c is formed.
The metal patterns 10a and 10b only need to be formed diagonally on the main pedestal 1, and the metal pattern 10a may be formed on the upper left side and the metal pattern 10b may be formed on the lower right side.

The metal patterns 10a and 10b are also formed on the side surfaces of the connecting portion 13 and the connecting portion 14, and are also formed on the bottom surfaces of the connecting portion 13 and the connecting portion 14 although not shown.
The metal patterns 10a and 10b on the bottom surface of the connection portion 14 are configured to be connected to the electrodes formed on the projecting portion 3a of the package with the conductive adhesive 5 or the like.

Further, as shown in FIG. 2, in the main pedestal 1, the thickness of the mounting portion 11 in the vertical direction is the same as the thickness of the connecting portion 13 and the connecting portion 14.
Therefore, since it cannot be directly installed on the substrate on the bottom surface of the inner concave portion of the ceramic package 3, the projecting portion 3a for installing the connection portion 14a of the main pedestal 1 is provided in the package 3.

With the configuration of the main pedestal 1 described above, even if externally generated vibration is applied to the connecting portion 14a via the protruding portion 3a, the connecting portion 13 including the plurality of gap portions 12 absorbs the vibration and alleviates the vibration. However, the influence of the vibration generated outside does not affect the crystal blank 2 mounted on the mounting portion 11.

As the crystal piece 2, for example, an AT cut in which thickness shear vibration is excited is used.
Excitation electrodes are formed on the front surface and the back surface of the crystal piece 2 and are connected to the electrode patterns 10a and 10b of the base 1 by a conductive adhesive 4.

Although a crystal resonator made of an AT-cut crystal piece 2 is used as the vibration element mounted on the main pedestal 1, for example, a surface acoustic wave (SAW: Surface Acoustic Wave) resonator or another piezoelectric vibrator or An oscillation element (vibration element) such as a micro electro mechanical system (MEMS) oscillator may be used.

Further, the main pedestal 1 on which the crystal piece 2 is mounted is housed and installed in the package 3, as shown in FIG.
The package 3 is provided with a two-step concave recessed portion, and the connecting portion 14 is mounted on the protruding portion (step portion) 3 a in the middle thereof and is connected to the electrode formed on the package 3. The stepped portion in the middle may be formed in the portion where the connecting portion 14 is mounted, and the stepped portion need not be formed in other portions.
As a result, the bottom surface of the mounting portion 11 does not come into contact with the bottom surface of the package 3.

The package 3 is made of ceramic or the like.
In the package 3, the main pedestal 1 is installed on the projecting portion 3a, so that a space can be formed below the mounting portion 11, and a circuit may be mounted in the space to form a vibrator.

Further, an oscillator circuit (IC) may be mounted in the space to configure an oscillator.
In addition, in FIG. 2, the two-step recess is formed on the front surface side, but the cross section in which the recess is also formed on the back surface has a substantially H shape, and the main base 1 and the crystal piece 2 are housed and arranged in the front recess. Then, the oscillator circuit may be formed by accommodating and mounting the oscillator circuit in the recess on the back surface.
The mounting of the pedestal 1 and the oscillation circuit on the package 3 is fixed by soldering or the like.

The oscillator circuit (IC) is housed in the front surface recess or the back surface recess of the package 3 and mounted on the bottom surface of the recess. A temperature compensation circuit other than the IC may be provided on the front substrate or the back substrate of the package 3. A temperature compensation type crystal oscillator (TCXO) is provided with the temperature compensation circuit.

A seam ring is formed around the surface of the package 3.
The seam ring is formed of silver (Ag) wax or the like around the surface of the package 3 to perform the seam sealing.
Then, a lid serving as a lid of the package 3 is formed so as to adhere to the seam ring. As the lid, Kovar plated with nickel is used.

[Another base: Fig. 3]
Next, another pedestal (another pedestal) according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 is a plan view of another pedestal.
The other pedestal is basically the same as the main pedestal 1, except that the connecting portion 14b is formed on the long side of the second surrounding portion, and the electrode pattern is formed on the connecting portion 14b. 10c and 10d are formed, and the projecting portion 3b of the package 3 is formed along the portion 13d forming the long side of the second surrounding portion so as to be connected to the connecting portion 14b.

That is, in FIG. 3, the connecting portion 14b projects in the upper and lower outer directions of the portion 13d forming the long side of the second surrounding portion. Therefore, the structure does not project to the left and right outside of the portion 13c that forms the short side of the second surrounding portion.
The mounting portion 11, the connecting portion 13, and the connecting portion 14 have the same thickness as the main pedestal 1.

As shown in FIG. 2, the electrode pattern 10c has a rectangular pattern in which the conductive adhesive 4 is applied to the lower left portion of the mounting portion 11 which overlaps with the crystal piece 2, and the square pattern is connected thereto at the first connecting portion. The second connecting portion pulls out to the lower left corner of the second enclosure through the portion 13a forming the left short side of the first enclosure, and the lower long side of the second enclosure is The connecting portion 14b formed on the constituting portion 13d is formed.

As shown in FIG. 1, the electrode pattern 10d has a rectangular pattern in which the conductive adhesive 4 is applied to the upper right portion of the mounting portion 11 which overlaps with the crystal piece 2, and the square pattern is connected thereto at the first connecting portion. The second connecting portion pulls out to the upper right corner of the second enclosure through the portion 13a that constitutes the right short side of the first enclosure, and constitutes the upper long side of the second enclosure. The connecting portion 14b formed in the portion 13d is formed.
It suffices that the metal patterns 10c and 10d are diagonally formed on another pedestal, and the metal pattern 10c may be formed on the upper left side and the metal pattern 10d may be formed on the lower right side.

The metal patterns 10c and 10d are also formed on the side surfaces of the connecting portion 13 and the connecting portion 14, and are also formed on the bottom surfaces of the connecting portion 13 and the connecting portion 14 although not shown.
The metal patterns 10c and 10d on the bottom surface of the connection portion 14 are configured to be connected to the electrodes formed on the projecting portion 3b of the package with the conductive adhesive 5 or the like.

[Effect of Embodiment]
According to the pedestal, the mounting portion 11 on which the crystal piece 2 is mounted, and the two connecting portions 14a that are provided in parallel to the opposing short sides of the mounting portion 11 and that are connected to the electrodes formed in the package 3 are provided. , A connecting portion 13 that connects the mounting portion 11 and the connecting portion 14a, and the connecting portion 13 includes a first enclosing portion that encloses the mounting portion 11, and a short side of the mounting portion 11 and a short length of the first enclosing portion. A first connecting portion that connects the portion 13a forming the side, a second surrounding portion that surrounds the first surrounding portion, a corner portion of the first surrounding portion, and a corner portion of the second surrounding portion are linked. Since the connecting portion 14a has a second connecting portion and the connecting portion 14a is provided on the portion 12c forming the short side of the second surrounding portion, vibration from the outside is transmitted to the connecting portion 14a. Even if it does, there is an effect that it is absorbed by the connecting portion 13 to reduce the influence on the mounting portion 11 and the phase noise characteristic can be improved.

According to another pedestal, the mounting portion 11 on which the crystal piece 2 is mounted and the two connecting portions 14b provided in parallel with each of the opposing long sides of the mounting portion 11 and connected to the electrodes formed in the package 3 are provided. And a connecting portion 13 that connects the mounting portion 11 and the connecting portion 14b, and the connecting portion 13 includes a first enclosing portion that surrounds the mounting portion 11, and a short side of the mounting portion 11 and the first enclosing portion. The first connecting portion that connects the portion 13a forming the short side, the second surrounding portion surrounding the first surrounding portion, the corner portion of the first surrounding portion and the corner portion of the second surrounding portion are formed. Since the second connecting portion has a second connecting portion and the connecting portion 14b is provided on the portion 13d forming the long side of the second surrounding portion, vibration from the outside is transmitted to the connecting portion 14b. Even if it is done, there is an effect that it is absorbed by the connecting portion 13 to reduce the influence on the mounting portion 11 and the phase noise characteristic can be improved.

INDUSTRIAL APPLICABILITY The present invention is suitable for a pedestal for a vibrating element, a vibrator, and an oscillator that can suppress the influence of external vibrations, improve vibration resistance, and improve phase noise characteristics.

DESCRIPTION OF SYMBOLS 1... Pedestal, 2... Vibrating piece (crystal piece), 3... Package, 3a, 3b... Projection part, 4, 5... Conductive adhesive, 10a, 10b, 10c, 10d... Electrode pattern, 11... Mounting part, 12a , 12b, 12c... Gap portion, 13... Connection portion, 13a... A portion forming the short side of the first enclosing portion, 13b... A portion forming the long side of the first enclosing portion, 13c... The second enclosing portion Forming a short side of 13d, a part forming a long side of the second surrounding portion, 14a, 14b... connecting part

Claims (7)

A pedestal for a vibrating element equipped with a vibrating element,
A mounting part on which a vibration element is mounted,
Two connecting portions which are provided in parallel with each short side of the mounting portion and which are connected to electrodes formed in the package;
A connecting portion that connects the mounting portion and the connecting portion,
The connecting portion includes a first enclosing portion that surrounds the mounting portion, a first connecting portion that connects a short side of the mounting portion and a short side of the first enclosing portion, and the first enclosing portion. A second enclosing portion that encloses the first enclosing portion, and a second connecting portion that connects the corner portion of the first enclosing portion and the corner portion of the second enclosing portion,
The said connection part is provided in the short side of the said 2nd surrounding part, The pedestal characterized by the above-mentioned. A pedestal for a vibrating element equipped with a vibrating element,
A mounting part on which a vibration element is mounted,
Two connecting portions that are provided in parallel with each long side of the mounting portion and that are connected to electrodes formed in the package;
A connecting portion that connects the mounting portion and the connecting portion,
The connecting portion includes a first enclosing portion that surrounds the mounting portion, a first connecting portion that connects a short side of the mounting portion and a short side of the first enclosing portion, and the first enclosing portion. A second enclosing portion that encloses the first enclosing portion, and a second connecting portion that connects the corner portion of the first enclosing portion and the corner portion of the second enclosing portion,
The said connection part is provided in the long side of the said 2nd surrounding part, The pedestal characterized by the above-mentioned. The pedestal according to claim 1 or 2, wherein the mounting portion, the connecting portion and the connecting portion have the same thickness. A first gap is provided between the long side of the mounting portion and the long side of the first enclosing section, and a second gap is provided between the long side of the first enclosing section and the long side of the second enclosing section. 4. The third gap portion is provided between the short side of the first enclosing portion and the short side of the second enclosing portion, and the third gap portion is provided. The pedestal shown. A vibrator comprising a vibrating element mounted on the pedestal according to any one of claims 1 to 4, and the vibrating element being installed on a step portion formed so as to project from a bottom surface of a package surface concave portion. A vibrating element is mounted on the pedestal according to any one of claims 1 to 4, the vibrating element is mounted on a step portion formed so as to project from a bottom surface of the recess on the surface of the package, and an oscillation circuit is mounted on the bottom surface of the recess on the surface of the package. Characteristic oscillator. A vibrating element is mounted on the pedestal according to any one of claims 1 to 4, the vibrating element is mounted on a step portion formed so as to project from the bottom surface of the package surface recess, and an oscillator circuit is mounted on the back surface recess of the package. Oscillator.