JP4089964B2 - Piezoelectric oscillator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface mount type piezoelectric oscillator used in electronic equipment such as portable communication equipment.
[0002]
[Prior art]
Conventionally, piezoelectric oscillators have been used in electronic devices such as portable communication devices.
[0003]
As such a conventional piezoelectric oscillator, for example, a recess is formed on the upper surface of a base, and a container body in which a piezoelectric vibration element is accommodated and an electronic component such as an IC element are mounted in the recess. Further, there is known a structure in which a lid body is further attached to the upper surface of the base and the opening surrounded by the lid is closed with the lid body so that the region surrounded by the inner surface of the recess and the lower surface of the lid is hermetically sealed. (For example, refer to Patent Document 1).
[0004]
As the lid body, for example, a wiring board having a plurality of wiring conductors is used, and when such a wiring board is used as a lid body, electronic components are also mounted on the lower surface of the lid body. The lid is electrically and mechanically bonded to the substrate by bonding the wiring conductor exposed on the lower surface thereof to the wiring conductor provided on the upper surface of the substrate via a conductive adhesive such as solder. Connected to.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-346119 (FIG. 1)
[0006]
[Problems to be solved by the invention]
However, in the above-described conventional piezoelectric oscillator, in order to satisfactorily attach the lid to the upper surface of the base body, it is necessary to form the side wall portion of the base body so as to surround the recesses to be somewhat thick. In this case, the area and volume of the base body are increased as the thickness of the side wall portion is increased, which makes it impossible to reduce the size of the piezoelectric oscillator.
[0007]
Further, in such a conventional piezoelectric oscillator, the electrical contacts between the base and the lid are concentrated on the outer periphery of the base, and one end of the wiring conductor needs to be led out to the outer periphery of the lid. Therefore, there is a tendency that the wiring length of each wiring conductor is increased correspondingly, and this also induces a disadvantage that the base becomes larger and cannot be used for downsizing the entire structure.
[0008]
The present invention has been devised in view of the above-described problems, and an object of the present invention is to provide a piezoelectric oscillator that is excellent in mechanical strength and capable of downsizing the entire structure.
[0009]
[Means for Solving the Problems]
The piezoelectric oscillator according to the present invention includes a container body in which a piezoelectric vibration element electrically connected to the wiring conductor is housed on a first circuit board having a plurality of wiring conductors. A second circuit board having at least one wiring conductor is placed and fixed on the upper surface of the first circuit board, and the upper surface of the first circuit board or the lower surface of the second circuit board is based on the vibration of the piezoelectric vibration element. A piezoelectric oscillator comprising an IC element for controlling oscillation output, wherein both ends are fixed to both circuit boards between the first circuit board and the second circuit board, and both A conductive support member electrically connected to the wiring conductor of the circuit board is interposed.
[0010]
The piezoelectric oscillator according to the present invention is characterized in that a hole for inserting the end of the support member is provided on the upper surface of the first circuit board and / or the lower surface of the second circuit board. To do.
[0011]
Furthermore, in the piezoelectric oscillator of the present invention, the hole portion of the first circuit board passes through the first circuit board, and the end portion of the support member inserted into the through hole is connected to the first circuit board. It is characterized by being exposed on the lower surface side of the substrate and functioning as an external connection terminal.
[0012]
Furthermore, in the piezoelectric oscillator of the present invention, a plurality of external connection terminals are provided on the lower surface of the first circuit board, and one of the wiring conductors of the second circuit board is a ground electrode, A part of the ground electrode is located above the IC element.
[0013]
According to the piezoelectric oscillator of the present invention, on the first circuit board having a plurality of wiring conductors, the container body in which the piezoelectric vibration element electrically connected to the wiring conductor is accommodated is mounted. A second circuit board having at least one wiring conductor is placed on and fixed to the upper surface of the container body, and both circuit boards are supported by support members that are electrically connected to the wiring conductors of both circuit boards. Since the first and second circuit boards are not so large, both the circuit boards are fixed firmly and firmly by the support members, and the mechanical strength of the piezoelectric oscillator is kept high. Will be able to. Moreover, the electrical connection between the first and second circuit boards is made by the above-described conductive support members, and the corresponding support members of the first and second circuit boards face each other. Since the wiring conductors of the first and second circuit boards can be arranged anywhere as long as they are places, the wiring length of the wiring conductors does not become unnecessarily long, which also serves to reduce the size of the piezoelectric oscillator. I can.
[0014]
Further, according to the piezoelectric oscillator of the present invention, by providing the hole for fitting the end of the support member on the upper surface of the first circuit board and / or the lower surface of the second circuit board, The member can be firmly fixed to the circuit board, and the mechanical strength of the piezoelectric oscillator can be improved.
[0015]
Furthermore, according to the piezoelectric oscillator of the present invention, the hole portion of the first circuit board is formed so as to penetrate the first circuit board, and the end portion of the support member inserted into the through hole is formed in the first circuit board. If the piezoelectric oscillator is mounted on an external wiring board such as a mother board if it is exposed on the lower surface side of the circuit board so as to function as an external connection terminal, the support member is directly joined to the external wiring board. This also has the advantage that the mounting strength of the piezoelectric oscillator can be improved.
[0016]
Furthermore, according to the piezoelectric oscillator of the present invention, one of the wiring conductors of the second circuit board is used as a ground electrode, and this ground electrode is positioned above the IC element, so that when the piezoelectric oscillator is used, The ground electrode functions as an electromagnetic shield layer, and noise contained in the oscillation signal can be reduced.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
[0018]
1 is a perspective view of a 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 of FIG. 1. A piezoelectric oscillator 10 shown in FIG. The container body 3 in which the piezoelectric vibration element 6 is accommodated is mounted, the second circuit board 2 is placed and fixed on the upper surface of the container body 3, and the container is mounted on the upper surface of the first circuit board 1. It has a structure in which an IC element 4 and an electronic component 9 are mounted and mounted in a region where the body 3 does not exist.
[0019]
The first circuit board 1 is formed to have a flat plate shape by a resin material such as a glass cloth base epoxy resin, polycarbonate, epoxy resin, polyimide resin, or a ceramic material such as glass-ceramic or alumina ceramic, On the upper surface, a wiring conductor 7 is deposited and formed in a predetermined pattern.
[0020]
The wiring conductor 7 provided on the first circuit board 1 is a film formed using a highly conductive metal material such as copper or silver, and the surface thereof has good solderability. For this purpose, Au plating or the like is applied, and Ni plating or the like is interposed between the Au plating and the wiring conductor 7 as an intermediate layer in order to provide solder resistance. Note that, instead of the above-described plating, preflux treatment may be performed to prevent formation of an oxide film.
[0021]
On the other hand, the container 3 mounted on the first circuit board 1 described above includes, for example, a substrate made of a ceramic material such as glass-ceramic or alumina ceramic, and a seal made of a metal such as 42 alloy, Kovar, or phosphor bronze. The ring includes a ring made of the same metal as the seal ring. The seal ring is attached to the upper surface of the substrate, and the lid is placed and fixed on the upper surface. The substrate is formed by, for example, printing / coating a conductor paste to be a wiring conductor 8 in a predetermined pattern on the surface of a ceramic green sheet obtained by adding / mixing an appropriate organic solvent or the like to ceramic material powder. After being laminated and press-molded, it is manufactured by firing at a high temperature, and the seal ring and lid body are manufactured by forming a metal such as 42 alloy into a predetermined shape using a well-known metal processing method. Is done. The seal ring thus manufactured is brazed to a conductor layer previously deposited on the upper surface of the substrate, and then the piezoelectric vibration element 6 is mounted and fixed on the upper surface of the substrate using a conductive adhesive. After that, the container body 3 is assembled by joining the above-described lid body to the upper surface of the seal ring by conventionally known resistance welding or the like.
[0022]
Further, as the piezoelectric vibration element 6 accommodated in the container body 3, for example, a pair of vibration electrodes is attached and formed on both main surfaces of a crystal piece cut into a rectangular shape by cutting with a predetermined crystal axis. When a fluctuation voltage from the outside is applied to the crystal piece of the crystal resonator element via a pair of vibration electrodes, thickness shear vibration is caused at a predetermined frequency. . Such a piezoelectric vibration element 6 is mechanically and electrically connected to the substrate of the container body 3 via a conductive adhesive.
[0023]
Such a piezoelectric vibration element 6 is hermetically sealed in a space surrounded by the upper surface of the substrate, the inner surface of the seal ring, and the lower surface of the lid, and the container body 3 is mounted on the first circuit board 1. At the same time, it is electrically connected to the wiring conductor 7 and the like.
[0024]
And the 2nd circuit board 2 mounted and fixed on the upper surface of the container body 3 mentioned above is formed with the same material as the 1st circuit board 1 mentioned above, Such 2nd circuit board 2 At least one wiring conductor 8 provided on the lower surface of the first circuit board 1 is also formed of the same material as the wiring conductor 7 of the first circuit board 1.
[0025]
The IC element 4 mounted on the first circuit board 1 controls the oscillation output based on the vibration of the piezoelectric vibration element 6 accommodated in the container body 3, specifically, the amplification / For example, a flip-chip type IC element having a plurality of bump electrodes on the lower surface is used.
[0026]
Note that other electronic component elements 9 such as a chip capacitor and a chip resistor are mounted on the upper surface of the first circuit board 1 and / or the lower surface of the second circuit board 2 as necessary.
[0027]
And between the 1st circuit board 1 and the 2nd circuit board 2 which were mentioned above, both ends are fixed to both the circuit boards 1 and 2, and the wiring conductor 7 of both the circuit boards 1 and 2 , 8 are electrically conductive strut members 5 that are electrically connected.
[0028]
Each of the support members 5 is formed of a metal material such as iron (Fe), white or phosphor bronze so as to form a columnar shape or a prism shape, and the height thereof is between the circuit boards. The height is set to be approximately equal to the interval, and both ends thereof are joined to the wiring conductors 7 and 8 of the first and second circuit boards 1 and 2 via a conductive adhesive such as solder. 2 is fixed to the circuit boards 1 and 2. Here, when solder is used as the conductive adhesive, it is preferable that the surface is subjected to solder plating, Sn plating or the like in order to improve the solder wettability of the wiring conductors 7 and 8.
[0029]
Such a piezoelectric oscillator 10 of this embodiment is a container in which a piezoelectric vibration element 6 electrically connected to the wiring conductor 7 is accommodated on a first circuit board 1 having a plurality of wiring conductors 7. The body 3 is mounted, and the second circuit board 2 having at least one wiring conductor 8 is mounted and fixed on the upper surface of the container body 3, and both the circuit boards 1 and 2 are connected to both circuit boards. Since the first and second circuit boards 1 and 2 are not increased in size, both circuits are fixed since they are fixed by the column members 5 that are electrically connected to the first and second wiring conductors 7 and 8. The substrates 1 and 2 can be fixed well and firmly by the support member 5, and the mechanical strength of the piezoelectric oscillator can be kept high. In addition, the electrical connection between the first and second circuit boards 1 and 2 is made by the conductive support member 5 described above. The support member 5 corresponds to the first and second circuit boards 1 and 2. The wiring conductors 7 and 8 of the first and second circuit boards 1 and 2 are unnecessarily long because the wiring conductors to be arranged may be located anywhere as long as the wiring conductors to be opposed face each other. This can be used to reduce the size of the piezoelectric oscillator.
[0030]
At this time, the IC element 4 located in the space sandwiched between the first circuit board 1 and the second circuit board 2 is smaller and smaller than the container body 3 in which the piezoelectric oscillator 10 is accommodated. Therefore, even if the height of the space is the same as the height of the container body 3, it can be arranged without any problem.
[0031]
When the piezoelectric oscillator 10 of the present embodiment described above is manufactured, first, a solder paste is selectively printed on the wiring conductor 7 of the first circuit board 1, and then the container body 3, the IC element 4, The electronic component element 9 and the column member 5 are mounted at predetermined positions on the first circuit board 1 and then reflowed, whereby the container body 3, the IC element 4, the electronic component element 9 and the column member 5 are connected to the first circuit board. Soldered onto 1. The electronic component element 9 attached to the lower surface of the second circuit board 2 is also mounted in the same manner. Then, the second circuit board 2 is placed on the upper surface of the container body 3 mounted on the first circuit board 1 via an adhesive made of an epoxy resin or the like, and mounted on the first circuit board 1. Then, the wiring conductor 8 of the second circuit board 2 is brought into contact with the upper surface of the pillar member 5 through the solder paste, and then the epoxy resin is cured and the solder is heated and melted to heat the container body 3 and The piezoelectric oscillator 10 is assembled by joining the support member 5 to the second circuit board 2.
[0032]
In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.
[0033]
For example, in the embodiment described above, the IC element 4 is mounted on the first circuit board 1, but instead, the IC element 4 is mounted on the lower surface of the second circuit board 2. It doesn't matter.
[0034]
In the above-described embodiment, the height of the support member 5 is set to a height substantially equal to the distance between the first circuit board 1 and the second circuit board 2. The upper surface and the lower surface of the second circuit board 2 are joined to both ends of the support member 5, but instead of this, as shown in FIG. 3, the upper surface of the first circuit board 1 and / or the second circuit board 2 are joined. A hole 31 for fitting the end of the column member 5 may be provided on the lower surface of the circuit board 2, and the end of the column member 5 may be fitted into the hole 31. In this case, since the support member 5 can be more reliably fixed to the circuit board, there is an advantage that the mechanical strength of the piezoelectric oscillator is further improved. Therefore, it is preferable to provide a hole 31 for fitting the end of the column member 5 on the upper surface of the first circuit board 1 and / or the lower surface of the second circuit board 2.
[0035]
Further, when the embodiment of FIG. 3 is adopted, the hole portion 31 is penetrated in the thickness direction of the first circuit board 1, and the end portion of the support member 5 inserted into the through hole is made the first circuit board 1. If it is exposed to the lower surface side of this, this exposed part can function as an external connection terminal. Thus, when the piezoelectric oscillator is mounted on an external wiring board such as a mother board, the support member 5 is directly joined to the external wiring board, so that there is an advantage that the mounting strength of the piezoelectric oscillator is improved. Therefore, it is preferable that the end portion of the support member 5 is exposed to the lower surface side of the first circuit board 1 to function as an external connection terminal.
[0036]
Furthermore, in the above-described embodiment, a plurality of external connection terminals 47 are provided on the lower surface of the first circuit board 1 so that the lower surface of the first circuit board 1 is a mounting surface, and the wiring of the second circuit board 2 is provided. If one of the conductors 8 is a ground electrode 48 and a part of the ground electrode 48 is disposed above the IC element 44, the ground electrode 48 functions as an electromagnetic shield layer when the piezoelectric oscillator is used. The noise contained in the oscillation signal can be reduced. Therefore, it is preferable that the lower surface of the first circuit board 1 is a mounting surface and the ground electrode 48 of the second circuit board 2 is positioned above the IC element 44.
[0037]
Furthermore, in the above-described embodiment, the crystal vibration element is used as the piezoelectric vibration element, but the present invention can be applied to the case where another piezoelectric vibration element such as a SAW filter is used as the piezoelectric vibration element instead. is there.
[0038]
Furthermore, in the embodiment described above, the lid of the container body 3 is bonded to the substrate via the seal ring, but instead, a metallized pattern for bonding is formed on the upper surface of the substrate, You may make it weld a cover body directly with respect to this metallization pattern.
[0039]
Furthermore, in the above-described embodiment, the seal ring is directly attached to the upper surface of the substrate of the container body 1, but instead of this, a frame made of a ceramic material or the like made of the same material as the substrate is provided on the upper surface of the substrate. The seal ring may be attached to the upper surface of the frame after being integrally attached.
[0040]
Further, in the above-described embodiment, in addition to the conductive support member, the insulating support member is fixed between the first circuit board and the second circuit board, and both ends are fixed to both circuit boards. In this case, there is also an advantage that the two circuit boards can be more firmly fixed.
[0041]
【The invention's effect】
According to the piezoelectric oscillator of the present invention, on the first circuit board having a plurality of wiring conductors, the container body in which the piezoelectric vibration element electrically connected to the wiring conductor is accommodated is mounted. A second circuit board having at least one wiring conductor is placed on and fixed to the upper surface of the container body, and both circuit boards are supported by support members that are electrically connected to the wiring conductors of both circuit boards. Since the first and second circuit boards are not so large, both the circuit boards are fixed firmly and firmly by the support members, and the mechanical strength of the piezoelectric oscillator is kept high. Will be able to. Moreover, the electrical connection between the first and second circuit boards is made by the above-described conductive support members, and the corresponding support members of the first and second circuit boards face each other. Since the wiring conductors of the first and second circuit boards can be arranged anywhere as long as they are places, the wiring length of the wiring conductors does not become unnecessarily long, which also serves to reduce the size of the piezoelectric oscillator. I can.
[0042]
Further, according to the piezoelectric oscillator of the present invention, by providing the hole for fitting the end of the support member on the upper surface of the first circuit board and / or the lower surface of the second circuit board, The member can be firmly fixed to the circuit board, and the mechanical strength of the piezoelectric oscillator can be improved.
[0043]
Furthermore, according to the piezoelectric oscillator of the present invention, the hole portion of the first circuit board is formed so as to penetrate the first circuit board, and the end portion of the support member inserted into the through hole is formed in the first circuit board. If the piezoelectric oscillator is mounted on an external wiring board such as a mother board if it is exposed on the lower surface side of the circuit board so as to function as an external connection terminal, the support member is directly joined to the external wiring board. This also has the advantage that the mounting strength of the piezoelectric oscillator can be improved.
[0044]
Furthermore, according to the piezoelectric oscillator of the present invention, one of the wiring conductors of the second circuit board is used as a ground electrode, and this ground electrode is positioned above the IC element, so that when the piezoelectric oscillator is used, The ground electrode functions as an electromagnetic shield layer, and noise contained in the oscillation signal can be reduced.
[Brief description of the drawings]
FIG. 1 is a transparent external perspective view of a piezoelectric oscillator according to an embodiment of the present invention.
2 is a cross-sectional view of the piezoelectric oscillator of FIG. 1 taken along line AA. FIG.
FIG. 3 is a cross-sectional view of a piezoelectric oscillator according to another embodiment of the present invention.
FIG. 4 is a cross-sectional view of a piezoelectric oscillator according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st circuit board 2 ... 2nd circuit board 3 ... Container body 4 ... IC element 5 ... Strut member 6 ... Piezoelectric vibration element 7, 8 ... Wiring Conductor 9 ... electronic component element 10 ... piezoelectric oscillator

Claims (4)

On the first circuit board having a plurality of wiring conductors, a container body in which a piezoelectric vibration element electrically connected to the wiring conductors is accommodated is mounted, and at least one piece is provided on the upper surface of the container body. An IC element that mounts and fixes a second circuit board having a wiring conductor and controls an oscillation output on the upper surface of the first circuit board or the lower surface of the second circuit board based on the vibration of the piezoelectric vibration element A piezoelectric oscillator comprising:
Between the first circuit board and the second circuit board, both ends are fixed to both circuit boards, and electrically conductive support members are electrically connected to the wiring conductors of both circuit boards. A piezoelectric oscillator characterized by interposing. 2. The piezoelectric device according to claim 1, wherein a hole for inserting and inserting an end of the support member is provided on the upper surface of the first circuit board and / or the lower surface of the second circuit board. Oscillator. The hole portion of the first circuit board penetrates the first circuit board, and the end portion of the support member inserted into the through hole is exposed to the lower surface side of the first circuit board. 3. The piezoelectric oscillator according to claim 2, wherein the piezoelectric oscillator is configured to function as an external connection terminal. A plurality of external connection terminals are provided on the lower surface of the first circuit board, one of the wiring conductors of the second circuit board is a ground electrode, and a part of the ground electrode is used as the IC element. The piezoelectric oscillator according to any one of claims 1 to 3, wherein the piezoelectric oscillator is positioned above.

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