JP2002198741A - Piezoelectric oscillator and assembling method for the piezoelectric oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric oscillator where the inside of the package can surely be dehumidified and the cost increase can be suppressed. SOLUTION: The piezoelectric oscillator 1 is provided with a crystal vibrator 3, a package 20 and a dryer 10. The package 20 is provided with a base 2 and a cover 4. The base 2 and the cover 4 are fixed with each other to contain air-tightly the crystal vibrator 3. The package 20 contains the dryer 10. The dryer 10 is made of a chemical compound that chemically adsorbs moisture and maintains a state of solid even when the compound absorbs the moisture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric oscillator having a quartz oscillator, and a container for accommodating the quartz oscillator and the like in an airtight state, and a method of assembling the piezoelectric oscillator.

[0002]

2. Description of the Related Art Electronic devices such as mobile phones include, for example,
The piezoelectric oscillator 120 shown in FIG. 3 and the like is used. The piezoelectric oscillator 120 includes, as shown in FIG.
A crystal oscillator 122. The container 121 includes a terminal 123 and a sealing tube 124.

[0003] The terminal 123 has a main body 123a made of a cylindrical insulator and a pair of terminal pins 123b. The pair of terminal pins 123b are conductive and parallel to each other. The pair of terminal pins 123b penetrates the main body 123a. The sealing tube 124 has a disc-shaped ceiling wall 124.
a and a cylindrical peripheral wall 124b. Peripheral wall 124
b is continuous with the periphery of the ceiling wall 124a.

In the sealing tube 124, a main body 123a is opposed to a ceiling wall 124a and a peripheral edge of the main body 123a is
The terminal 123 is attached in a state of contacting the inner surface of the terminal b.
When the sealing tube 124 and the terminal 123 are fixed to each other, the inside of the sealing tube 124 becomes airtight.

[0005] The crystal oscillator 122 includes a crystal blank 125 made of crystal and a pair of electrodes 126. The crystal blank 125 is formed in a plate shape having a rectangular planar shape.
The pair of electrodes 126 is formed in a thin film made of copper or the like. The pair of electrodes 126 are formed on both surfaces of the crystal blank 125. FIG. 3 shows only one electrode 126. The crystal unit 122 includes a pair of electrodes 12
6 are attached to the terminal pins 123b of the terminals 123, respectively, and are accommodated in the container 121.

[0006]

The above-described piezoelectric oscillator 1
In order to maintain good electrical characteristics such as vibration characteristics after completion, it is necessary to remove water from the container 121. Therefore, for example, the piezoelectric oscillator 120
The inside of the container 121 is set to a nitrogen gas atmosphere or kept in a vacuum.

Further, the quartz oscillator 122 and the sealing tube 1
In order to prevent moisture or the like from adhering to the inner surface of the H.24, for example, as shown in Japanese Patent Application Laid-Open No. 10-163781, It has been proposed to store in a low humidity atmosphere. In this case, the cost of storing the intermediate assembly has increased, and the cost of the piezoelectric oscillator 120 itself has tended to increase.

When the above-mentioned intermediate assembly is stored in the atmosphere, for example, as shown in Japanese Patent Application Laid-Open No. 9-246867, the inner surfaces of the quartz oscillator 122 and the sealing tube 124 are removed. It has been proposed that nitrogen gas or dry air be blown on the surface to remove adhering moisture. If the nitrogen gas or dry air is blown before the terminal 123 and the sealing tube 124 are fixed, the time required for assembling the piezoelectric oscillator 120 tends to be long. Also in this case, the man-hours required for assembly and the like increase, and the cost of the piezoelectric oscillator 120 itself tends to increase.

Further, the terminal 1 is placed in a vacuum lower than the atmospheric pressure.
23 and the sealing tube 124 were fixed, and the inside of the container 121 was evacuated. Therefore, it is necessary to assemble the piezoelectric oscillator 120 in a vacuum chamber or the like. Therefore, the cost of the equipment required for assembly has risen, and the cost of the piezoelectric oscillator 120 itself has tended to rise.

Accordingly, an object of the present invention is to provide a piezoelectric oscillator and a method of assembling the piezoelectric oscillator, which can surely dehumidify the inside of the container, suppress the required cost and time required for assembling, and suppress a rise in cost. Is to do.

[0011]

According to a first aspect of the present invention, there is provided a piezoelectric oscillator including a container and a quartz oscillator, wherein the quartz oscillator is provided with a housing. In a piezoelectric oscillator housed in a container in an airtight state, a drying member housed in the container at an interval from the quartz oscillator is provided, and the drying member chemically adsorbs moisture and absorbs moisture. It is characterized by being composed of a compound that maintains a solid state.

According to a second aspect of the present invention, there is provided a piezoelectric oscillator comprising:
2. The piezoelectric oscillator according to claim 1, wherein the drying member is applied to an inner surface of the container.

According to a third aspect of the present invention, there is provided the piezoelectric oscillator assembling method according to the first or second aspect, wherein the containers are fixed to each other to hermetically seal the quartz oscillator. It has a base and a lid that are housed in a state, and the base and the lid are fixed in an atmosphere of dry air or dry nitrogen at atmospheric pressure.

According to a fourth aspect of the present invention, there is provided the piezoelectric oscillator assembling method according to the first or second aspect, wherein the containers are fixed to each other to hermetically seal the quartz oscillator. It has a base and a lid that are housed in a state, and the base and the lid are fixed in a vacuum.

According to the first aspect of the present invention, the drying member accommodated in the container absorbs moisture. For this reason, even if the quartz oscillator is accommodated in a container having moisture adhered to the inner surface and the container is sealed, the moisture adhered to the inner surface of the container is adsorbed to the drying member. Further, the moisture adhering to the inner surface of the container is adsorbed to the drying member without removing the water adhering to the inner surface of the container before the sealing.

According to the second aspect of the present invention, since the drying member is applied to the inner surface of the container, the drying member can surely adsorb moisture adhering to the inner surface of the container.

According to the third aspect of the present invention, the base and the lid are fixed in the atmosphere of the atmospheric pressure, and the quartz oscillator is housed in the container in an airtight state. For this reason, it is possible to suppress the cost of equipment required for assembling the piezoelectric oscillator.

According to the present invention, the base and the lid are fixed in a vacuum lower than the atmospheric pressure, and the quartz oscillator is housed in the container in an airtight state. For this reason, the inside of the container is maintained at the above-described vacuum, and moisture or the like attached to the inner surface of the container is easily vaporized. Therefore, the moisture attached to the inner surface of the container is adsorbed on the drying member.

It should be noted that the atmospheric pressure described in this specification indicates the atmospheric pressure at a place where a piezoelectric oscillator is assembled.
atm (atmospheric pressure). For this reason, the atmospheric pressure referred to in the present specification changes as appropriate depending on the location where the piezoelectric oscillator is assembled, the weather, and the like. Further, the vacuum described in this specification indicates a state of pressure lower than the atmosphere of the place where the piezoelectric oscillator is assembled. For this reason, the vacuum in this specification does not necessarily mean a state without any substance or the atmosphere.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a piezoelectric oscillator according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the piezoelectric oscillator 1 includes a quartz oscillator 3, a package 20 as a container, and a drying member 10.
And

As shown in FIGS. 1 and 2, the crystal unit 3 includes a crystal piece 7 made of crystal and a pair of extraction electrodes 8.
a, 8b. The crystal blank 7 is formed in a plate shape having a rectangular planar shape and a constant thickness.

The extraction electrodes 8a and 8b are arranged at one end of the crystal blank 7 along the width direction of the crystal blank 7 with an interval therebetween. The extraction electrode 8a is provided on one surface of the crystal blank 7, and the extraction electrode 8b is provided on the other surface of the crystal blank 7. In the illustrated example, the extraction electrode 8
a is provided on the upper surface of the crystal blank 7, and the extraction electrode 8b is
It is provided on the lower surface of the crystal piece 7. Thus, the extraction electrodes 8a and 8b are provided on both surfaces of the crystal blank 7. The extraction electrodes 8a and 8b are made of, for example, a conductive metal such as gold or copper, formed in a thin film having a square planar shape, and attached to the surface of the crystal blank 7.

When the lower surface of the crystal piece 7 faces the surface 12a of the bottom wall 12 of the base 2 which will be described later,
It corresponds to an electrode 5b described later. At this time, the extraction electrode 8
a is located above an electrode 5a to be described later.

The package 20 includes a base 2 and a lid 4 as shown in FIGS. Base 2
Is formed by laminating a known insulating substrate made of ceramic or the like and circuit elements and the like. The base 2 includes a bottom wall 12 and a plurality of peripheral walls 13. The bottom wall 12
The planar shape is a rectangular flat plate. The bottom wall 12 is larger than the crystal piece 7 of the crystal resonator 3. The peripheral wall 13 is provided with the bottom wall 12.
Of the bottom wall 12 is provided over the entire periphery of the bottom wall 12.

The base 2 is provided with a pair of electrodes 5a and 5b inside the peripheral wall 13 and on the surface 12a of the bottom wall 12. The pair of electrodes 5a and 5b are electrically connected to the circuit element and the like. The electrodes 5 a and 5 b are arranged at an end of the bottom wall 12 along the width direction of the bottom wall 12 with an interval therebetween. Each of the electrodes 5a and 5b has a square planar shape.

The electrode 5b is opposed to the extraction electrode 8b of the crystal unit 3. The electrode 5a is located below the extraction electrode 8a of the crystal resonator 3. The electrodes 5a and 5b are made of, for example, a conductive metal such as gold or copper, are formed in a thin film shape, and are attached to the surface 12a of the bottom wall 12.

Further, the base 2 is provided with electrodes (not shown) on the bottom side of the bottom wall 12. The electrodes are electrically connected to the electrodes 5a, 5b and the like. The electrodes are used to electrically connect to the base 2, that is, a conductor pattern such as a printed wiring board on which the package 20 is mounted. At least a metal film is formed on an end surface 13a of the peripheral wall 13 remote from the bottom wall 12. The metal film is made of, for example, a conductive metal such as gold, and is provided over the entire circumference of the peripheral wall 13.

The lid 4 is made of ceramic and is a flat plate having a rectangular planar shape. The lid 4 has substantially the same size as the bottom wall 12. The lid 4 has a substantially constant thickness. The lid 4 has a metal film formed on a surface of a base material made of ceramic. The metal film is made of, for example, a conductive metal such as gold.

When the lid 4 is attached to the base 2, the drying member 10 is spaced from the quartz oscillator 3 in a space 40 surrounded by the inner surface 13 b of the peripheral wall 13, the bottom wall 12 and the lid 4. Will be accommodated. The space 40 is provided in the package 2
It is within 0.

In the illustrated example, the drying member 10 is connected to the bottom wall 1.
2 is applied to the surface 12a. In the present invention,
The drying member 10 may be applied to the inner surface 13b of the peripheral wall 13 as long as it does not interfere with the crystal unit 3,
It may be applied to the surface opposite to 2. The bottom wall 1
2, the inner surface 13b of the peripheral wall 13 and the surface of the lid 4 facing the bottom wall 12 form the inner surface of the container described in this specification.

The drying member 10 is made of a compound that chemically adsorbs moisture and maintains a solid state even if it absorbs moisture. As the compound forming the drying member 10, for example, an alkali metal oxide, an alkaline earth metal oxide, a sulfate,
Metal halides, perchlorates and organic substances.

Examples of the alkali metal oxide include sodium oxide (Na 2 O) and potassium oxide (K 2 O). Examples of the alkaline earth metal oxide include calcium oxide (CaO), barium oxide (BaO), and magnesium oxide. (MgO).

As the sulfate, lithium sulfate (Li
2SO4), sodium sulfate (Na2SO4), calcium sulfate (CaSO4), magnesium sulfate (MgSO4),
Cobalt sulfate (CoSO4), gallium sulfate (Ga2 (S
O4) 3), titanium sulfate (Ti (SO4) 2), nickel sulfate (NiSO4) and the like. As these sulfates, anhydrous salts are preferably used.

Examples of the metal halide include calcium chloride (CaCl 2) and magnesium chloride (MgCl 2).
2), strontium chloride (SrCl2), yttrium chloride (YCl3), copper chloride (CuCl2), cesium fluoride (CsF), tantalum fluoride (TaF5), niobium fluoride (NbF5), calcium bromide (CaBr2), odor Cerium bromide (CeBr3), selenium bromide (SeBr4), vanadium bromide (VBr2), magnesium bromide (MgB
r2), barium iodide (BaI2), magnesium iodide (MgI2) and the like. As these metal halides, anhydrous salts are preferably used.

The perchlorate includes barium perchlorate (Ba (ClO4) 2), magnesium perchlorate (Mg
(ClO4) 2). As these perchlorates, anhydrous salts are preferably used.

Further, in addition to these inorganic compounds, an organic material can be used for the drying member 10. However, in this case as well, it must be one that chemically adsorbs moisture and maintains a solid state even if it absorbs moisture.

When assembling the piezoelectric oscillator 1 having the above-described structure, first, a conductive adhesive 6a is applied to each of the electrodes 5a and 5b of the base 2 having the drying member 10 applied to the bottom wall 12 in advance. The extraction electrodes 8a and 8b of the crystal unit 3 are overlaid on the adhesive 6a. When the adhesive 6a is cured, the quartz oscillator 3 is fixed to the electrodes 5a and 5b. Then, the electrode 5b and the extraction electrode 8b of the crystal unit 3 are electrically connected by the adhesive 6a.

Thereafter, a conductive adhesive 6b is applied to the surface of the crystal unit 3 located above the electrodes 5a and 5b. When the adhesive 6b is cured, the bonding strength of the crystal unit 3 to the base 2 is improved. Then, the electrode 5a and the extraction electrode 8a of the crystal unit 3 are electrically connected by the adhesive 6b.

Thus, the inner surface 13 of the bottom wall 12 and the peripheral wall 13
The crystal oscillator 3 is attached to the base 2 in a shape housed in a space 40 surrounded by b. Further, the base 2 to which the crystal resonator 3 is attached forms an intermediate assembly described in this specification.

When the lid 4 is attached to the base 2, the cover 4 is placed in dry air at atmospheric pressure where moisture is intentionally reduced.
Alternatively, the base 2 on which the crystal unit 3 is mounted is carried into an atmosphere of a dry nitrogen gas (dry nitrogen) in which moisture is intentionally reduced at atmospheric pressure or a vacuum intentionally made lower in pressure than atmospheric pressure. . The dry air with the intentionally reduced moisture and the dry nitrogen gas with the intentionally reduced moisture form an atmosphere at atmospheric pressure.

The base 2 and the lid 4 are fixed over the entire circumference of the peripheral wall 13 using a well-known resistance welding machine or ultrasonic welding machine. Since the base 2 and the lid 4 are fixed over the entire circumference of the peripheral wall 13, the space 40 is kept airtight. For this reason, the space 40 and the crystal unit 3 accommodated in the space 40 are shut off from the outside of the package 20.

Thus, the crystal unit 3 and the drying member 10 are housed in the package 20 in an airtight state. Then, moisture in the atmosphere in the package 20 is adsorbed on the drying member 10 and the space 40, that is, the package 2 is removed.
The inside of 0 is dehumidified. Thus, the base 2 and the lid 4 are
Fix in dry air at atmospheric pressure or dry nitrogen at atmospheric pressure or in vacuum.

According to the present embodiment, since the drying member 10 accommodated in the package 20 absorbs moisture, the bottom wall 1
Even when moisture adheres to the surface 12a of the bottom wall 2 and the inner surface 13b of the peripheral wall 13, the quartz oscillator 3 is housed in the base 2, the base 2 is sealed with the lid 4, and the surface 12a of the bottom wall 12 is closed. And moisture adhering to the inner surface 13b of the peripheral wall 13 and the like
It is adsorbed to zero.

Before fixing the base 2 and the lid 4,
The moisture is adsorbed on the drying member 10 without removing the moisture attached to the surface 12a of the bottom wall 12, the inner surface 13b of the peripheral wall 13, and the like. Therefore, the inside of the package 20 can be surely dehumidified. For this reason, it is possible to prevent the water from adhering to the crystal resonator 3. Therefore, it is possible to suppress the deterioration of the vibration characteristics of the crystal unit 3 and the change in the vibration characteristics of the crystal unit 3 due to aging.

Further, since the drying member 10 adsorbs moisture, the inside of the package 20 of the assembled piezoelectric oscillator 1 can be dehumidified without intentionally blowing a dry gas or the like with reduced moisture before assembling. Therefore, it is not necessary to remove the moisture by blowing a dry gas or the like with a reduced moisture intentionally before assembling.

Therefore, it is possible to reduce the cost of equipment required for assembling the piezoelectric oscillator 1 and to reduce the required man-hours for assembling the piezoelectric oscillator 1. Therefore, the cost of the piezoelectric oscillator 1 can be prevented from rising.

The drying member 10 is connected to the bottom wall 12 of the base 2.
Since the drying member 10 is applied to the inner surface of the package 20, such as the surface 12a, the drying member 10 can surely adsorb the moisture attached to the inner surface of the package 20.

Further, even if the piezoelectric oscillator 1 is assembled not in dry air or a nitrogen gas atmosphere in which moisture has been intentionally reduced, but in the air, the moisture sealed in the package 20 can be reduced by the drying member 10. Is adsorbed. For this reason, the cost required for the equipment required for assembling the piezoelectric oscillator 1 can be suppressed, and a rise in the cost of the piezoelectric oscillator 1 itself can be suppressed.

Further, when the package 20 is assembled in an atmosphere of dry air or a nitrogen gas in which the moisture is intentionally reduced, since the moisture in the above-described atmosphere is originally small, the moisture sealed in the package 20 becomes: The drying member 10 surely adsorbs it. Therefore, since the piezoelectric oscillator 1 can be assembled in the atmosphere, the cost of equipment required for assembling the piezoelectric oscillator 1 can be reduced, and the cost of the piezoelectric oscillator 1 can be further prevented from rising.

When the base 2 and the lid 4 are fixed in a vacuum lower than the atmospheric pressure, the pressure in the package 20 becomes lower than the atmospheric pressure, and the moisture sealed in the package 20 is easily vaporized. . Therefore, the moisture adhered to the inner surface of the package 20 can be reliably absorbed by the drying member 10. Therefore, the inside of the package 20 of the piezoelectric oscillator 1 can be more reliably dehumidified.

In the above-described embodiment, the adhesive 6a
Is applied, and after attaching the crystal unit 3 to the base 2, an adhesive 6b is further applied. However, in the present invention, without applying the adhesive 6b,
It is a matter of course that a crystal unit for attaching the crystal unit 3 to the base 2 may be provided only by the adhesive 6a.

[0052]

As described above, according to the first aspect of the present invention, the drying member accommodated in the container absorbs moisture. For this reason, even if the quartz oscillator is accommodated in a container having moisture adhered to the inner surface and the container is sealed, the moisture adhered to the inner surface of the container is adsorbed to the drying member. Further, the moisture adhering to the inner surface of the container is adsorbed to the drying member without removing the water adhering to the inner surface of the container before the sealing. Therefore,
The inside of the container can be surely dehumidified.

Since the drying member adsorbs moisture adhering to the inner surface of the container, the interior of the container is not dehumidified without intentionally storing the intermediate assembly in the course of assembling the piezoelectric oscillator in an atmosphere in which the moisture is reduced. it can. Further, before assembling, the inside of the container can be dehumidified without intentionally spraying a dry gas or the like with reduced moisture.

For this reason, it is possible to suppress the cost of equipment required for assembling the piezoelectric oscillator. The required man-hour required for assembling the piezoelectric oscillator can be reduced. Therefore, it is possible to suppress a rise in cost of the piezoelectric oscillator.

According to the second aspect of the present invention, since the drying member is applied to the inner surface of the container, the drying member can surely adsorb moisture adhering to the inner surface of the container. For this reason, it is possible to surely dehumidify the inside of the container without having to intentionally store the intermediate assembly in an atmosphere in which the moisture content has been reduced or spraying a dry gas or the like in which the moisture content has been intentionally reduced before assembly. Therefore, it is possible to further suppress a rise in the cost of the piezoelectric oscillator.

According to the third aspect of the present invention, the base and the lid are fixed in an atmosphere of atmospheric pressure, and the quartz oscillator is housed in a container in an airtight state. For this reason, when assembling the piezoelectric oscillator, it is possible to suppress the cost of necessary equipment. Therefore, in addition to being able to dehumidify the inside of the container, a rise in the cost of the piezoelectric oscillator can be further suppressed.

According to the fourth aspect of the present invention, the base and the lid are fixed in a vacuum lower than the atmospheric pressure, and the crystal unit is housed in a container in an airtight state. For this reason, the inside of the container is maintained at the above-described vacuum, and moisture or the like attached to the inner surface of the container is easily vaporized. For this reason, the moisture adhering to the inner surface of the container is reliably absorbed by the drying member. Therefore, in addition to suppressing a rise in the cost of the piezoelectric oscillator, the inside of the container can be more reliably dehumidified.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a piezoelectric oscillator according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the piezoelectric oscillator shown in FIG.

FIG. 3 is a perspective view showing a partial cross section of a conventional piezoelectric oscillator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric oscillator 2 Base 3 Quartz crystal oscillator 4 Lid 10 Drying member 12a Surface (inner surface of container) 13b Inner surface (inner surface of container) 20 Package

Continued on the front page (72) Inventor Tadashi Saito 6-1-1, Fujimi, Tsurugashima-shi, Saitama F-term in Pioneer F A (reference) 4D052 AA00 HA05 HA06 HA07 HA08 HA12 HA13 HB05 5J079 AA04 BA01 BA43 HA07 HA09 HA17 HA28 HA29 5J108 MM02

Claims (4)

[Claims] 1. A piezoelectric oscillator having a container and a crystal oscillator, wherein the crystal oscillator is housed in the container in an airtight state, wherein the piezoelectric oscillator is housed in the container at an interval from the crystal oscillator. A piezoelectric oscillator comprising: a drying member, wherein the drying member is made of a compound that chemically adsorbs moisture and maintains a solid state even when it absorbs moisture. 2. The piezoelectric oscillator according to claim 1, wherein the drying member is applied to an inner surface of the container. 3. The container has a base and a lid fixed to each other and accommodating the quartz oscillator in an airtight state, and the base and the lid are fixed in an atmosphere of dry air or dry nitrogen at atmospheric pressure. 3. The method for assembling a piezoelectric oscillator according to claim 1, wherein 4. The container according to claim 1, wherein the container has a base and a lid fixed to each other and accommodating the quartz oscillator in an airtight state, and the base and the lid are fixed in a vacuum. A method for assembling the piezoelectric oscillator according to claim 2.