JP2002280865A - Piezo device - Google Patents

Abstract

(57) Abstract: A piezoelectric device has a rectangular box shape in which a plurality of ceramic thin plates are stacked, and a base 11 in which an AT-cut quartz vibrating piece 14 is mounted in an empty space, and an inner surface of a glass thin plate. And a lid 12 on which a tuning fork type quartz vibrating piece 15 is mounted.
This is a composite piezoelectric oscillator including a package 13 in which a lid is bonded to an upper surface of a base and both quartz vibrating pieces are hermetically sealed. The two quartz-crystal vibrating reeds are arranged so that the base ends 14a and 15a overlap each other when viewed in a plan view, and are orthogonal to each other in the length direction. A free space in which no crystal vibrating piece is present is defined inside the package, and an IC chip 21 constituting an oscillation circuit for driving the AT-cut crystal vibrating piece is surface-mounted on the bottom surface 11a of the base. You. [Effect] Package size can be reduced and package
An electronic component such as an IC chip can be arranged by effectively utilizing the free space in the device, and a piezoelectric device such as a smaller and thinner composite oscillator can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric device such as a piezoelectric vibrator / piezoelectric oscillator or a SAW device used for electronic equipment, and more particularly, to a base made of an insulating material such as ceramic and having a glass lid covered with a low melting glass. The present invention relates to a piezoelectric device for hermetically sealing a vibrating piece made of a piezoelectric material such as quartz in a package joined by the above method.

[0002]

2. Description of the Related Art Conventionally, in electronic devices such as various information / communication devices, OA devices, and consumer devices, a piezoelectric vibrator, a piezoelectric vibrating piece and an IC chip are sealed in the same package as a clock source of an electronic circuit. Piezoelectric devices such as oscillators and real-time clock modules are widely used. Particularly in recent years, in the field of small information devices such as mobile computers and IC cards, and communication devices such as mobile phones, piezoelectric devices have been further reduced in size and thickness as devices have become smaller and thinner. There is a demand for a surface mount type piezoelectric device suitable for mounting the device on a circuit board.

In general, a surface mount type piezoelectric device is known which has a structure in which a piezoelectric vibrating reed and, if necessary, electronic components are hermetically sealed in a package in which a lid is joined to a base made of an insulating material. For example, in a piezoelectric device equipped with a tuning-fork type piezoelectric vibrating reed, a transparent thin glass plate is used for a lid 3 bonded to a base 2 of a package 1 as shown in FIG. Irradiation allows the frequency of the piezoelectric vibrating reed 4 to be adjusted, and a sealing hole 5 is provided through the bottom surface of the base and closed by a sealing material 6 such as Au-Sn so that the inside of the package is vacuum-sealed. What has been developed.

Recently, Japanese Patent Application Laid-Open No. 2000-59169 discloses that a motherboard can be mounted at a high density in an electronic device such as a computer using a plurality of types of crystal units.
A piezoelectric vibrator array in which a plurality of press-fit sealed piezoelectric vibrators are arranged in parallel in order to save space, and are integrally molded and sealed. In particular, if each piezoelectric vibrator is arranged with its lead reversed, wiring becomes easier,
In addition to miniaturization, improvement in mass productivity and cost reduction can be achieved.

[0005]

Recently, particularly in the field of communication technology, a plurality of resonators having different performances, such as different oscillation frequency bands for communication and clock, are mounted on one electronic device. Is required. Further, in order to cope with further miniaturization of electronic equipment, a piezoelectric device such as a composite vibrator or a composite oscillator in which a plurality of piezoelectric vibrators are housed in one package is required. However,
In the conventional structure described in Japanese Patent Application Laid-Open No. 2000-59169, a press-fit sealing type piezoelectric vibrator in which a piezoelectric vibrating piece is hermetically sealed is individually integrated in each package. And there is a limit to miniaturization.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and has as its object to mount a plurality of piezoelectric vibrating reeds in a single package and reduce the size and thickness thereof. It is an object of the present invention to provide a surface-mount type piezoelectric device which can perform the following. It is a further object of the present invention to provide a higher performance piezoelectric device with good production yield and at lower cost.

[0007]

According to the present invention, in order to achieve the above object, a package having a base made of an insulating material, a lid joined to an upper surface of the base, and a base at a base end portion are provided. A first piezoelectric vibrating piece mounted cantilevered and hermetically sealed in the package, and a second piezoelectric vibrating piece mounted cantilevered on the lid at the base end and hermetically sealed in the package Wherein the first and second piezoelectric vibrating reeds are arranged so as to overlap with each other at the base end when viewed in a plan view and not to overlap with each other at their distal ends when viewed in plan. Is provided.

By arranging the base ends of the two piezoelectric vibrating pieces so as to overlap each other, a plurality of piezoelectric vibrating pieces of different oscillation frequencies and different types are hermetically sealed in a single package, and at the same time, the package Plane dimensions can be reduced. Furthermore, depending on the dimensions of both piezoelectric vibrating reeds,
A region where no piezoelectric vibrating reed is present can be defined in a plane. This area can be effectively used, for example, for mounting various electronic components such as an IC chip, a capacitor, and a resistor.

In one embodiment, the first and second piezoelectric vibrating reeds are arranged in a direction orthogonal to each other in a length direction when viewed in plan. This maximizes the area of the lid or base where none of the piezoelectric vibrating reeds exist, and facilitates the arrangement of the electronic components.

In one embodiment, a plurality of piezoelectric vibrators and electronic components are housed in a single package by mounting the electronic components on a lid or a base in this area and hermetically sealing the electronic components in a package. Thus, a small and thin piezoelectric device can be obtained. In particular, a composite piezoelectric oscillator is realized by this electronic component constituting an oscillation circuit of the first or second piezoelectric vibrating reed.

In one embodiment, the base has a concave portion provided in a region where none of the piezoelectric vibrating reeds exist when viewed in plan, and the electronic component is disposed in the concave portion. ing. As a result, a sufficient space in the height direction for arranging the electronic components is secured, the assembling thereof is facilitated, and the thickness of the base can be reduced to reduce the thickness of the package. In particular, when electronic components are connected by wire bonding, it is possible to avoid contact and interference with the wiring of the bonding wires and the piezoelectric vibrating reed.

In another embodiment, the base has a concave portion provided in a region including the tip portion of the first piezoelectric vibrating piece when viewed in a plan view, and the electronic component is located in the concave portion. Are located. As a result, a wider space for disposing electronic components is obtained, and electronic components having larger dimensions can be mounted. In addition, a plurality of electronic components can be mounted integrally and relatively freely arranged in the recess.

In still another embodiment, the electronic component is mounted on an inner surface of the lid. In particular, when the oscillation circuit of the second piezoelectric vibrating reed is mounted on the inner surface of the lid, both are arranged and connected close to each other, and the length of the line can be shortened. Frequency adjustment becomes possible.

The base and lid constituting the package can be used in various combinations. In one embodiment, the configuration may be the same as the conventional configuration in which the base has a rectangular box shape and the lid has a rectangular thin plate shape. In particular, when the base has a laminated structure of a ceramic thin plate, a concave portion for arranging the above-described electronic component is formed, or an internal wiring for connecting the first piezoelectric vibrating reed and the electronic component is formed. It is easy to provide a terminal for connecting to the wiring on the lid side on the joint surface with the lid.

In one embodiment, the second piezoelectric vibrating reed may be a tuning fork type piezoelectric vibrating reed, in which case if the lid is made of a transparent glass material, the outer side of the package after sealing is sealed. By irradiating the vibrating element with a laser beam, fine adjustment of the frequency can be easily performed by removing the metal weight attached to the resonator element.

In one embodiment, the base has a recess provided in a region corresponding to the tip of the second piezoelectric vibrating reed. Accordingly, even if the tip portion of the second piezoelectric vibrating piece vibrates or vibrates largely due to a shock due to a drop or an external mechanical vibration, there is little possibility that the second piezoelectric vibrating piece collides with the bottom surface of the base and is broken. improves.

Furthermore, a part of the wiring circuit provided on the base can be exposed inside the recess.
When fine-tuning the frequency of the tuning-fork type quartz vibrating reed, the metal weight material blown by the laser beam from the tip of the tuning fork-type quartz vibrating reed tends to adhere to the wiring in the recessed part, and thus has an adverse effect on the electronic components and the first piezoelectric vibrating reed. Is less likely to occur.

In another embodiment, the first piezoelectric vibrating reed can be an AT-cut quartz vibrating reed, for example, in combination with a second piezoelectric vibrating reed which is a tuning fork type piezoelectric vibrating reed.
A composite piezoelectric oscillator having oscillation frequencies in two different bands is obtained according to the application or demand.

In one embodiment, the base has a sealing hole at the bottom communicating with the inside of the package, and the sealing hole is closed after the base and the lid are joined, and the inside of the package is closed. Vacuum sealed. Accordingly, corrosion of the electrodes of each resonator element, wiring inside the package, and the like can be prevented, and high durability and reliability of the piezoelectric device can be secured. In particular, when the lid is made of glass, the frequency of the second piezoelectric vibrating reed can be finely adjusted precisely in a vacuum environment by irradiating a laser beam from the outside after vacuum sealing of the package.

[0020]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In each of the drawings, similar components are denoted by the same reference numerals. FIGS. 1A and 1B schematically show the configuration of a composite piezoelectric oscillator which is a first embodiment of a piezoelectric device to which the present invention is applied. This composite piezoelectric oscillator includes a package 1 having a rectangular box-shaped base 11 and a thin plate-shaped lid 12.
3 in which two quartz-crystal vibrating pieces 14, 15 are hermetically sealed. In this embodiment, an AT-cut crystal vibrating piece and a tuning-fork type quartz vibrating piece in different frequency bands are appropriately selected as the crystal vibrating piece according to the application.

The base 11 is formed in a substantially rectangular box shape by laminating a plurality of ceramic thin plates. A pair of connection terminals 16 are formed on the bottom surface 11 a of the space defined inside the base 11, and the AT-cut crystal vibrating piece 1 is formed thereon.
4 is supported substantially horizontally by cantilevering the base end 14a and fixing a pair of connection electrodes provided on the base end to the corresponding connection terminal 16 with a conductive adhesive 17. .

The lid 12 is formed of a rectangular thin plate made of a transparent glass material, and has a pair of connection terminals 18 and a wiring pattern drawn therefrom formed on the inner surface thereof. The tuning-fork type crystal vibrating piece 15 is cantilevered substantially horizontally at a base end 15a by fixing a pair of connection electrodes provided at the base end to a corresponding connection terminal 18 with a conductive adhesive 19. It is supported by. The lid 12 is hermetically joined to the upper end surface of the base 11 with the low-melting glass 20 as in the conventional case.

As shown in FIG. 1A, the AT-cut quartz-crystal vibrating piece 14 is disposed so as to extend in the vicinity of one (upper side) side 11b of the base 11 along the longitudinal direction. The tuning-fork type quartz vibrating piece 15 has a base end 15 a
The tip 11b is overlapped with the base end 14a of the T-cut quartz-crystal vibrating reed and is perpendicular to the AT-cut quartz-crystal vibrating reed 14 in the longitudinal direction, that is, the tip 15b is placed on the opposite side (lower side in the figure) of the base 11c. It is arranged to extend toward. The package 13 can be reduced in planar size by overlapping the base ends 14a and 15a of both quartz-crystal vibrating pieces.

If the tuning-fork type quartz vibrating piece 15 is sufficiently longer than the width of the AT-cut quartz vibrating piece 14, the tip portions 14b, 15b of the two quartz vibrating pieces do not overlap in a plane, so that the impact due to dropping or external mechanical Even if the two tip portions vibrate vertically or vibrate due to mechanical vibration, there is no possibility of collision or damage or loss due to collision, and the impact resistance is improved. In addition, the tip 15b of the tuning-fork type quartz vibrating piece has a sufficient height between the cavity bottom face 11a of the base, so that a gap with the inner surface of the lid 12 can be secured even if the tip is slightly inclined downward. In this case, there is little possibility of collision with the cavity bottom surface 11a.

Further, inside the package, a free space is defined along the lower side 11c of the base 11 in which none of the quartz vibrating pieces exist. In this free space,
An IC chip 21 constituting an oscillation circuit for driving the AT-cut quartz-crystal vibrating piece 14 is surface-mounted on the cavity bottom surface 11a of the base. In this embodiment, the IC chip 21 is connected to the electrode pattern 22 formed on the bottom surface 11a of the cavity by wire bonding. Since no quartz-crystal vibrating piece is arranged above the IC chip 21, wire bonding is easy. Further, even when the IC chip 21 is relatively thick, it can be accommodated without difficulty.

The bonding terminals of the electrode pattern 22
A part thereof is connected to the connection terminal 16 via a wiring pattern (not shown) also on the bottom surface 11a of the cavity, and the other part is connected via a wiring circuit 23 provided inside the base 11 to the base. 11 are connected to external electrodes 24 on the bottom surface. A connection terminal 18 and an internal terminal (not shown) connected to the wiring pattern are provided on the lid 12 at a joint portion with the base 11. The internal terminals (not shown) connected to the external electrodes 25 are provided. The internal terminal of the lid and the internal terminal of the base are electrically connected by, for example, a conductive adhesive after the lid is joined to the base, thereby making the tuning-fork type quartz vibrating piece 15 conductive to the external electrode 25.

The terminals and electrode patterns of the base 11 are formed by screen printing a metal wiring material such as W or Mo on the surface of a ceramic thin plate and then baking it.
It is formed by plating. The terminals and the wiring pattern of the lid 12 are formed, for example, by depositing or sputtering a metal wiring material on the surface of the glass thin plate, or by etching the metal wiring material formed on the surface. In another embodiment, the lid 12 is etched by etching a thin glass plate having an electrode film formed on the surface.
Can be formed into a predetermined rectangular size, and at the same time, the terminals and the wiring pattern can be formed, so that good dimensional accuracy and positional accuracy can be obtained.

In the manufacturing process of the composite piezoelectric oscillator of this embodiment, each of the crystal vibrating pieces 14 and 15 is mounted on the base 11 and the lid 12 in a separate step, and the oscillation frequency is roughly adjusted to a predetermined frequency range. . Next, the lid 12 is air-tightly bonded to the base 11 with the low-melting glass 20 to be integrated, and then a conductive adhesive (not shown) is applied to the bonding portion to apply a corresponding internal terminal of the lid 12 to the base 11. To the internal terminal of

In this embodiment, as described with reference to the prior art in FIG. 10, a sealing hole 36 penetrating the bottom of the base 11 is provided, and the sealing hole is formed after the base and the lid are joined. By closing the package 13 with the sealing material 37 in a vacuum atmosphere, the package 13 can be vacuum-sealed. When the sealing hole 36 is provided at a position overlapping the vibrating electrode of the AT-cut quartz vibrating piece 14, the quartz vibrating piece 14 is etched by ion beam etching through the sealing hole before closing.
The front excitation electrode on the surface can be partially removed to fine tune the frequency.

After the package 13 is vacuum-sealed, the oscillation frequency of the tuning-fork type quartz vibrating piece 15 is finely adjusted. This is the lid 12
While measuring the frequency via the internal terminal or the external electrode 25 exposed on the outer surface, a laser beam 27 is irradiated from the outside through the lid, and the tip 15 of each vibrating arm of the tuning-fork type quartz vibrating piece 15 is measured.
This is performed by partially removing the metal weight in the frequency adjustment region provided in b. At this time, the metal weight material blown by the laser beam from the frequency adjustment region has an AT below.
Since the cut quartz-crystal vibrating piece 14 does not exist, there is no possibility that the cut quartz-crystal vibrating piece reattaches to the vibrating piece and adversely affects its frequency. In another embodiment, after the package 13 is vacuum-sealed, a laser beam 26 is irradiated from the outside through the lid 12 while measuring the frequency through the external electrode 24 in the same manner.
By partially removing the excitation electrode 14c of the crystal resonator element, the oscillation frequency of the AT-cut crystal resonator element 14 can be finely adjusted.

In this embodiment, the two quartz-crystal vibrating pieces are arranged on the base and the lid such that the base ends fixed in plan view overlap each other and are orthogonal to the longitudinal direction. This makes it possible to effectively utilize the space inside the package to integrally mount electronic components such as an IC chip, and at the same time, to reduce the size and thickness of the package. In addition, the size of the resonator element is reduced in size and thickness as the frequency of the resonator is increased. However, by configuring as in the present invention, it is possible to use a package having a dimension conventionally used as a standard as it is. This is convenient because two vibrating pieces and an oscillation circuit can be incorporated into the device.

Further, in assembling the package, the two types of crystal vibrating pieces are separately mounted on the base and the lid, and after the frequency is roughly adjusted, the base and the lid are joined to each other, so that work efficiency and productivity are improved. If there is a defect in such a crystal vibrating piece, only one of the pieces needs to be discarded, so that the manufacturing yield can be improved and the manufacturing cost can be reduced. Further, since the frequency of each crystal resonator element can be finely adjusted with high precision after the package is sealed, a higher quality composite piezoelectric oscillator can be obtained.

FIGS. 2A and 2B schematically show a composite piezoelectric oscillator according to a modification of the first embodiment. This modification is different from the first embodiment in that the concave portion 28
However, this embodiment is different from the first embodiment in FIG. 1 in that it is formed in a region corresponding to the front end 15b of the tuning-fork type quartz vibrating piece 15 and has sufficient vertical and horizontal dimensions including the front end. Due to the recessed portion 28, even if the tip portion 15b of the tuning-fork type quartz vibrating piece vibrates largely or vibrates up and down due to a shock due to a drop or external mechanical vibration, it is more likely that the tip portion 15b will collide with the cavity bottom surface 11a and be damaged. Since it is reduced, the impact resistance is greatly improved.

If a part of the wiring circuit 23 inside the base 11 is provided so as to be exposed at the bottom surface of the concave portion 28, the tip of the tuning fork type quartz vibrating piece 15 is adjusted when the frequency is adjusted by the laser beam 27. The metal weight material blown off from the portion 15b is also made of a metal material and easily adheres to the wiring portion exposed in the recess 28. Therefore, it is preferable that the metal weight material is less likely to reattach to the AT-cut quartz crystal vibrating piece 14 and the IC chip 21 and adversely affect the same.

FIGS. 3A and 3B schematically show a composite piezoelectric oscillator according to a second embodiment of the present invention. In the second embodiment, a concave portion 29 is provided along a lower side 11c of the base 11 in a free space on the vacant bottom surface 11a of the base 11 where none of the above-described quartz vibrating pieces exist. The difference from the embodiment of FIG. 2 is that the IC chip 21 is mounted on the bottom. As a result, a sufficient space is secured in the height direction for the bonding wires connecting the IC chip 21, so that the assembling work is facilitated, and the thickness of the base 11 is reduced, so that the package 13
Can be made thinner. Further, the contact between the bonding wire and the crystal vibrating piece can be avoided, whereby the frequency fluctuation and the failure of the crystal vibrating piece can be reliably prevented. Further, it is preferable that the metal weight material blown off at the time of adjusting the frequency of the tuning-fork type quartz vibrating piece 15 by the laser beam is less likely to be re-adhered to the IC chip 21 and is less likely to have an adverse effect.

FIGS. 4, 5A and 5B schematically show a composite piezoelectric oscillator according to a third embodiment of the present invention. In the third embodiment, a recess 30 which is larger than the recess 29 of the second embodiment is provided on the bottom surface 11a of the base 11 on the tip end side of the AT-cut quartz vibrating piece 14 over the entire width of the bottom surface of the space. It is different from the second embodiment in FIG. 3 in that an IC chip 21 is provided and a part thereof is mounted on the bottom so that a part thereof overlaps the AT-cut quartz-crystal vibrating piece 14 in a plane.
The IC chip 21 of this embodiment is surface-mounted on the wiring circuit 23 exposed on the bottom surface of the recess 30 by flip-chip bonding.

The concave portion 30 has a large area including the tip portion of the AT-cut quartz-crystal vibrating piece 14 in addition to the free space in which none of the above-described quartz-crystal vibrating pieces exist in a plan view. The chip 21 can be accommodated. Further, by mounting the IC chip 21 by flip-chip bonding, a gap is secured between the IC chip 21 and the AT-cut quartz-crystal vibrating piece 14 as compared with the case of wire bonding, and the possibility of contact with the IC chip 21 can be reduced. Further, the recess 3
By adjusting the depth of 0, an IC chip having a higher size can be accommodated.

FIGS. 6, 7A and 7B show a composite piezoelectric oscillator according to a modification of the third embodiment. In this embodiment, a plurality of IC chips 31 to 3
4 and FIGS. 5 (A) and 5 (B) in that
Is different from the embodiment. The IC chips 31 to 33 constitute an oscillation circuit for driving the AT-cut crystal vibrating piece 14,
The wiring circuit 23 formed on the bottom surface of the recess 30 is mounted by flip chip bonding. In another embodiment, an electronic component such as a capacitor or a resistor other than the IC chip can be mounted on the bottom surface of the recess 30 as needed.

As described above, since the area of the concave portion 30 is large, a plurality of electronic components can be relatively freely arranged without difficulty. Further, the IC chip 3 is provided on the bottom of the recess 30.
Wiring patterns for connecting 1 to 33 can be formed relatively easily. Therefore, even a piezoelectric device having a relatively complicated configuration can be accommodated in a single package. In particular, the electronic components disposed below the AT-cut quartz-crystal vibrating piece 14 are less likely to be reattached to the metal weight material that is blown off when the frequency of the tuning-fork-type quartz-crystal vibrating piece 15 is adjusted by a laser beam, and are less susceptible to adverse effects. Become.

FIGS. 8, 9A and 9B schematically show a composite piezoelectric oscillator according to a fourth embodiment of the present invention. This piezoelectric oscillator further comprises an IC chip 34 constituting an oscillation circuit for driving the tuning-fork type quartz vibrating piece 15 mounted on the inner surface of the lid 12, and FIGS.
Is different from the third embodiment. The IC chip 34 is disposed above the tip 14 b of the AT-cut quartz vibrating piece 14,
2 is connected by flip chip bonding to an electrode pattern 35 formed on the inner surface. A part of the bonding terminal of the electrode pattern 35 is a tuning fork type quartz vibrating piece 15.
And the other part is connected to the wiring pattern drawn out to the outside, and is electrically connected to the external electrode 25 via the internal terminals of the lid 12 and the base 11.

In this embodiment, the frequency can be adjusted while the tuning-fork type quartz vibrating piece 15 and its oscillation circuit are mounted on the lid 12, and both are arranged and connected close to each other to reduce the line length. Because it can be shortened, the influence of noise etc. is small,
The frequency can be adjusted to a desired numerical range with higher accuracy. Further, since the influence of noise can be reduced during use, a higher performance piezoelectric oscillator can be obtained. Also, A
Since the IC chips 32 to 34 are arranged above and below the tip portion 14b of the T-cut quartz vibrating reed, respectively, when the chip vibrates up and down or vibrates due to an impact due to a drop or external mechanical vibration. Impulse by the chip,
The deflection can be reduced, and the base 11 or the lid 12
Since there is no possibility of damage due to a direct collision with the vehicle, impact resistance is greatly improved.

Although the preferred embodiments of the present invention have been described in detail above, as will be apparent to those skilled in the art, the present invention is implemented by adding various changes and modifications to the above embodiments within the technical scope thereof. be able to. For example, in the above embodiment, the tuning-fork type quartz vibrating piece and the AT-cut quartz vibrating piece are combined, but any one of them may be combined with a SAW (surface acoustic wave) resonator. Further, an AT-cut crystal vibrating piece may be mounted on the lid. The lid is provided with a recessed part on its inner surface by etching or stamping, etc.
In addition, the crystal vibrating piece can be accommodated therein to prevent damage during handling.

Also, in each of the embodiments other than FIG. 1, a sealing hole is provided in the bottom of the base, the package is vacuum-sealed by closing in a vacuum atmosphere, and then the frequency of the tuning-fork type quartz vibrating piece is adjusted. Can be fine-tuned. Also, by ion beam etching through this sealing hole,
The frequency can be finely adjusted by partially removing the excitation electrode on the surface of the AT-cut quartz-crystal vibrating piece 14.

[0044]

As described above, in the piezoelectric device according to the present invention, the first and second piezoelectric vibrating reeds overlap each other at the base ends when viewed in a plan view in the package and overlap each other in the longitudinal direction. By arranging them in orthogonal directions, the size of the package containing the plurality of piezoelectric vibrating pieces is reduced, and the space inside the package is effectively used.
Electronic components such as an oscillation circuit of a piezoelectric vibrating piece can be arranged, and a smaller and thinner piezoelectric device such as a composite oscillator can be realized. Furthermore, since the base and the lid can be joined after separately adjusting the frequency of the first and second piezoelectric vibrating pieces, and the frequency can be finely adjusted after sealing the package, high quality and stability can be achieved. A piezoelectric device having excellent quality can be manufactured with good yield at low cost.

[Brief description of the drawings]

FIG. 1A is a plan view showing a first embodiment of the present invention,
(B) is a longitudinal sectional view thereof.

FIG. 2A is a plan view showing a modification of the first embodiment;
(B) is a longitudinal sectional view thereof.

FIG. 3A is a plan view showing a second embodiment of the present invention;
(B) is a longitudinal sectional view thereof.

FIG. 4 is a plan view showing a third embodiment of the present invention.

5A is a longitudinal sectional view of FIG. 4, and FIG. 5B is a sectional view taken along line VV of FIG.

FIG. 6 is a plan view showing a modification of the third embodiment of the present invention.

7A is a longitudinal sectional view of FIG. 6, and FIG. 7B is a view of FIG.
It is sectional drawing in the VII-VII line.

FIG. 8 is a plan view showing a fourth embodiment of the present invention.

9A is a longitudinal sectional view of FIG. 8, and FIG. 9B is a view of FIG.
It is sectional drawing in the IX-IX line.

FIG. 10 is a longitudinal sectional view showing a conventional piezoelectric vibrator.

[Explanation of symbols]

 1, 13 Package 2, 11 Base 3, 12 Lid 4 Piezoelectric vibrating piece 5, 36 Sealing hole 6, 37 Sealing material 11a Bottom space 11b, 11c Side 14 AT cut quartz vibrating piece 15 Tuning fork type quartz vibrating piece 14a , 15a Base end 14b, 15b Tip 14c Excitation electrode 16, 18 Connection terminal 17, 19 Conductive adhesive 20 Low melting glass 21 IC chip 22 Electrode pattern 23 Wiring circuit 24, 25 External electrode 26, 27 Laser beam 28 to 30 recess 31-34 IC chip 35 electrode pattern

Claims (15)

[Claims] 1. A package having a base made of an insulating material and a lid joined to an upper surface of the base, a cantilever mounted on the base at a base end, and hermetically sealed in the package. A first piezoelectric vibrating reed, and a second piezoelectric vibrating reed mounted on the lid at a base end and hermetically sealed in the package, wherein the first and second piezoelectric vibrating reeds are: A piezoelectric device, wherein the piezoelectric devices are arranged so as to overlap with each other at the base ends when viewed in a plan view and not to overlap with each other at their distal ends. 2. The piezoelectric device according to claim 1, wherein the first and second piezoelectric vibrating reeds are arranged in directions perpendicular to each other in a length direction when viewed in a plan view. 3. The piezoelectric device according to claim 1, further comprising an electronic component mounted on the lid or the base and hermetically sealed in the package. 4. The device according to claim 1, wherein the base has a recess provided in a region where none of the piezoelectric vibrating reeds exist when viewed in a plan view, and the electronic component is arranged in the recess. The piezoelectric device according to claim 3, wherein 5. The base has a concave portion provided in a region including the distal end portion of the first piezoelectric vibrating reed when viewed in a plan view, and the electronic component is arranged in the concave portion. The piezoelectric device according to claim 3, wherein: 6. The piezoelectric device according to claim 4, wherein a plurality of the electronic components are arranged in the recess. 7. The piezoelectric device according to claim 3, wherein the electronic component is mounted on an inner surface of the lid. 8. The piezoelectric device according to claim 3, wherein the electronic component forms at least an oscillation circuit of the first or second piezoelectric vibrating reed. 9. The piezoelectric device according to claim 1, wherein the base has a rectangular box shape, and the lid has a rectangular thin plate shape. 10. The piezoelectric device according to claim 1, wherein the lid is formed of a transparent glass material. 11. The piezoelectric device according to claim 10, wherein the second piezoelectric vibrating reed is a tuning fork type piezoelectric vibrating reed. 12. The piezoelectric device according to claim 11, wherein the base has a recess provided in a region corresponding to the tip of the second piezoelectric vibrating reed. 13. The piezoelectric device according to claim 12, wherein a part of the wiring circuit provided on the base is exposed inside the recess. 14. The piezoelectric device according to claim 1, wherein the first piezoelectric vibrating reed is an AT-cut quartz vibrating reed. 15. The base has a sealing hole communicating with the inside of the package at the bottom, and the sealing hole is closed after the base and the lid are joined to vacuum seal the inside of the package. 15. The method according to claim 1, wherein
The piezoelectric device according to any one of the above.