JPH06196959A - Crystal oscillator - Google Patents

Abstract

PURPOSE:To provide a crystal oscillator capable of sufficiently removing flux stuck to a circuit board at the time of soldering by using a washing solution gently matched with environment and preventing the infiltration of flux gas into a container at the time of assembling and having high rust resistance. CONSTITUTION:Two through holes 33 are formed on a hermetic base 32 consisting of iron and two lead wires 34 passing through the holes 33 are arranged. A conductive holding member 35 is integrally provided on each lead wire 34 and a crystal oscillator element 37 is fixed on the members 35. A cap 38 is placed on the frange part 32a of the base 32 and hermetically joined. Two insulating projections 39 are formed at both the end parts of a face opposed to the circuit board P of the base 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal unit.

[0002]

2. Description of the Related Art Generally, a crystal oscillator is used for electrical reference frequency generation and frequency selection by combining with an electric circuit by utilizing its natural mechanical vibration and the piezoelectric effect and inverse piezoelectric effect of the crystal. Has been done.

As shown in FIG. 15, a conventional crystal unit has a metal base, that is, a so-called hermetic base 1 with two bases.
One through hole 2 is bored, and a crystal oscillator piece 5 is attached on two lead wires (inner leads) 3 penetrating these through holes 2 via step-like conductive holding members 4, respectively. Further, the cap 6 is hermetically sealed. In this case, the hermetic base 1 is integrally formed with a flange portion 1a having a projection 8 formed all around, and the cap 6 is also formed in a shape having a flange portion 6a corresponding thereto. The flange portion 1a of the hermetic base 1 and the flange portion 6a of the cap 6 are brought into contact with each other, and the flange portion 6a of the cap 6 and the protrusion 8 of the flange portion 1a of the hermetic base 1 are joined by resistance welding,
The crystal unit 5 is hermetically sealed.

The lead wire 3 is fixed in the through hole 2 of the hermetic base 1 by glass fusion so as to be insulated from the hermetic base 1. The lead wire 3 is formed of, for example, Kovar (Fe—Ni—Co alloy) or FeNi alloy having good compatibility with the glass 9. The hermetic base 1 is made of metal. Then, the crystal unit 5 is placed and fixed on the holding member 4 by the conductive adhesive 10.

Such a crystal unit 11 is mounted on a circuit board such as a printed wiring board. For example, on a double-sided printed wiring board having wiring patterns on both sides, a crystal unit 1
1 is mounted, since the hermetic base 1 is made of metal, an insulating sheet is provided on the back surface of the hermetic base 1 so as not to short-circuit the wiring pattern, or a bent portion is provided in the middle of the lead wire 3 to form a lead wire. When 3 is inserted into the lead insertion hole of the printed wiring board, it is stopped at the position of the bent portion so that the hermetic base 1 is floated above the printed wiring board.

[0006]

By the way, the crystal unit 11 is usually fixed by soldering so as to be in close contact with the circuit board. At that time, since the flux mainly used as a solvent is removed, the conventional crystal unit 11 is conventionally used. Then, for example, cleaning is performed using a cleaning liquid such as CFC or trichloroethane.

However, in recent years, environmental damage due to solvents such as CFCs has become a problem, and as an alternative to these, for example, the quartz oscillator 11 is cleaned using a chlorine-based solvent, water, hot water, or the like. Is proposed.
However, since chlorine-based solvents and the like have a weaker cleaning power than chlorofluorocarbons and the like, there is a problem that the flux and the like attached to the contact portion between the crystal unit 11 and the circuit board cannot be sufficiently removed.

Further, when the crystal unit 11 is cleaned using a chlorine-based solvent, water, warm water, etc., the base and the cap are made of metal, and therefore the base and the cap are rustproof in the cleaning process. There was also a problem that

On the other hand, the present applicant previously applied for a crystal oscillator 21 having a structure as shown in FIG. 16 (Japanese Patent Application No. 4-246).
832). In this crystal oscillator 21, the base 22 is made of ceramics in order to prevent the base 22 from warping. In the crystal unit 21, the frame-shaped body 24 and the lid body 25 forming the cap 23 need to be sealed, but, for example, the equipment cost for seam welding or laser welding is high and the processing capacity is small. Therefore, it has been proposed to perform sealing by high-frequency induction heating, which has low equipment cost and large processing capacity.

However, if the sealing is performed by high frequency induction heating, the following problems occur. That is, according to this method, solder is placed between the joint surface of the frame-shaped body 24 and the joint surface of the lid body 25 in which the metallized layer of tungsten W, molybdenum Mo or silver Ag / palladium Pd is formed on the ceramics. Then, this solder is melted and sealed by high frequency induction heating, but at that time, the flux used for soldering is vaporized and penetrates into the container and remains,
This adversely affects the crystal unit 5. in this case,
It is possible to use solder with a low flux content, but even in that case, the effect on the crystal unit 5 cannot be completely removed.

The present invention has been made in view of the above points of the conventional example, and an object thereof is to sufficiently remove the flux adhered during soldering to a circuit board using an environment-friendly cleaning liquid. In addition, it is possible to provide a crystal resonator that is excellent in rust resistance and that prevents flux gas from entering the container during assembly.

[0012]

The first invention is, for example,
As shown in FIG. 1, in a crystal oscillator in which a crystal oscillator piece 37 held by a lead wire 34 penetrating the base 32 is hermetically sealed by the base 32 and a cap 38, , A plurality of protrusions 39 for forming a gap between the circuit board P to be mounted.

Further, for example, as shown in FIG.
0 and the cap 71 may be formed of an insulating material such as ceramics, and the base 40 and the cap 71 may be bonded with an adhesive 75.

In the second invention, for example, as shown in FIG. 8, a crystal resonator piece 37 held by a lead wire 34 penetrating a base 60 is constituted by the base 60 and a cap 61. In a quartz oscillator which is arranged inside and hermetically sealed by soldering the joint portion of the base 60 and the cap 61, the base 60 and the cap 61
The packing 63 for cutting off the portion where the solder 64 is to be placed and the inside of the container 62 is placed at the joint portion of the above.

[0015]

In the first aspect of the invention, as shown in FIGS. 1 to 3, since the base 32 is provided with the plurality of protrusions 39, when mounted on the circuit board P, A gap is formed between the circuit board P and the cleaning liquid flows in the gap.

Further, since the base 40 and the cap 71 formed of an insulating material such as ceramics are adhered by the adhesive 75, the durability against rust is improved and the adhesion area is widened, so that the base 40 and the cap are increased. The adhesion between 71 is increased.

In the second aspect of the invention, the packing 63 blocks the portion where the solder 64 is to be placed from the inside of the container 62. Therefore, for example, when the solder 64 is melted by high frequency heating, the soldering flux is used. This gas is prevented from entering the container 62.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a crystal resonator according to the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment of the first invention. As shown in these figures, in the crystal unit 31 of the present embodiment, for example, two through holes 33 are formed in a hermetic base 32 as a base made of metal such as iron, and these through holes 33 are penetrated. The two lead wires 34 are arranged. The two lead wires 34 are hermetically sealed by fusion of the glass G. Further, a step-like conductive holding member 35 is integrally provided on each lead wire 34, and a crystal oscillator piece 37 is fixed on these holding members 35 by a conductive adhesive 36.

On the flange portion 32a of the hermetic base 32, a cap 38 made of metal such as iron and having a flange portion 38a is placed, and these are hermetically joined. The hermetic base 32 and the cap 38 both have an elongated shape, and both ends thereof are formed in an arc shape.

On the other hand, two protrusions 39 are provided on the back surface of the hermetic base 32, that is, both ends of the surface facing the circuit board (for example, a printed wiring board or the like) P on which the crystal unit 31 is mounted. These protrusions 39 are, for example,
It is made of an insulating material such as ceramics, and is composed of a fan-shaped flat plate member so as to match the shape of the hermetic base 32. In this case, each protrusion 39 is fixed to the hermetic base 32 by, for example, forming a metallized layer on the joint surface of each protrusion 39 and welding the metallized layer and the joint surface of the hermetic base 32 with solder.

According to the present embodiment having such a configuration, since the two projections 39 are provided on the back surface of the hermetic base 32, when mounted on the circuit board P, a gap is formed between the hermetic base 32 and the hermetic base 32. It As a result, when the cleaning liquid is supplied in the cleaning process, the cleaning liquid sufficiently flows between the hermetic base 32 and the circuit board P.
For example, even when a cleaning liquid such as a chlorine-based solvent, water, or warm water having a low cleaning power is used, the soldering flux can be almost completely removed.

Although ceramics were used as the material of the protrusions in the above-mentioned embodiments, the present invention is not limited to this, and heat-resistant adhesive tapes or four-foot adhesives can be used as long as they are insulating materials. It is also possible to use a material obtained by applying and curing a liquid material of a chlorinated ethylene resin. Also, when mounting on a circuit board with wiring on one side (back side),
A conductive material such as metal can also be used as the material of the protrusions.

Further, the position, shape, and number of the protrusions are not limited to those in the above-mentioned embodiment, and can be arbitrary. However, it is preferable that the structure is stable when mounted on a circuit board.

Next, regarding another embodiment of the first invention,
The portions corresponding to those in the above embodiment will be described with the same reference numerals.

FIG. 4 shows another embodiment of the present invention. As shown in the figure, in this embodiment, the hermetic base 40 is made of ceramics, and a protrusion 41 having the same shape as that of the above-mentioned embodiment is integrally formed under the hermetic base 40. Then, the frame-like body 42 is airtightly joined to the hermetic base 40 so as to surround the crystal oscillator piece 37, and the lid 43 is airtightly joined to the frame-like body 42. In this case, both the frame-shaped body 42 and the lid body 43 may be made of ceramics, glass or metal, and the frame-shaped body 42 and the lid body 43 may be integrally formed of metal.

The hermetical sealing of this embodiment is particularly performed in the frame-shaped body 42.
When at least one of the lid 43 and the lid 43 is an insulating material such as ceramics or glass, an epoxy resin adhesive,
An adhesive such as a polyimide adhesive is used. That is, the adhesive is interposed between the peripheral edge surface on one side of the frame-shaped body 42 and the hermetic base 40, and the peripheral edge surface on the other side of the frame-shaped body 42 and the lid 4 are arranged.
An adhesive agent is interposed between the outer peripheral surface and the outer peripheral surface of the outer peripheral surface 3. Then, the hermetic base 40 and the frame-shaped body 42 and the frame-shaped body 42 and the lid 43 are bonded to each other by the adhesive force of these adhesives. The rest of the configuration and operation are the same as in the above-mentioned embodiment, so a description thereof will be omitted.

According to this embodiment having such a structure, in particular, the hermetic base 40, the frame-like body 42 and the lid 43 are all made of ceramics, and the hermetic base 40, the frame-like body 42 and the lid 43 are formed. When it is configured to be bonded with an adhesive, a container that does not rust can be provided, and the rust resistance of this type of crystal unit 31 can be significantly improved, and it can be used with a metal hermetic base. It is possible to eliminate the need for an insulating sheet and reduce the number of parts used. In addition, since the metal container is joined using resistance welding when it is hermetically sealed, the crystal resonator piece is easily affected by the welding pressure and the characteristics of the resonator may change slightly. According to the example, such a possibility does not occur. Moreover, although the entire joining surface cannot be adhered by resistance welding, when the adhesive is used, the entire joining surface can be adhered, so that the hermetic base 40 and the frame-like body 42 are bonded together. The adhesive strength can be greatly improved.

FIG. 5 shows still another embodiment of the first embodiment, which is applied to a so-called chip type crystal oscillator. In this embodiment, similarly to the embodiment shown in FIG. 4, a protrusion 51 is formed on the lower portion of a hermetic base 50 made of ceramics, and a lead portion is formed in the vicinity of the protrusion 51. That is, the Ag / Pd layer 5 connected to the holding member 35 on the upper surface of the hermetic base 50.
2 is formed, and this Ag / Pd layer 52 is connected to the Ag / Pd layer 54 of the protrusion 51 of the hermetic base 50 via the Ag / Pd layer 53 formed through the hermetic base 50. Then, a Ni plating layer 55 and a solder layer 56 are formed on the Ag / Pd layer 54 to form a connection portion with the circuit board P. The rest of the configuration and operation are the same as in the above-mentioned embodiment, so a description thereof will be omitted.

FIGS. 6 to 7 show still another embodiment of the first embodiment. In this embodiment, the cap 71 is formed by integrally forming the frame-like body 42 and the lid 43 of the embodiment shown in FIG. 4 with an insulating material such as ceramics. Both the hermetic base 40 and the cap 71 are made of ceramics, and the ceramic container 72 is made up of the hermetic base 40 and the cap 71.
The crystal oscillator piece 73 is hermetically sealed inside.

The airtight sealing of this embodiment is performed by using an adhesive 75 such as an epoxy resin adhesive or a polyimide adhesive as in the above embodiment. The adhesive 75 is the cap 7
The cap 71 is adhered to the hermetic base 40 by the adhesive force of the adhesive agent 75, which is provided over the entire circumference between the peripheral end surface on the opening side of 1 and the hermetic base 40. In the case of the present embodiment, the cap 71 is the crystal unit 7
It is composed of one frame-shaped body with a lid, in which a recessed portion 74 capable of accommodating 3 etc. is opened, but the hermetic base 40 and the two projections 41 provided at both ends of its back surface are the same as those shown in FIG. Is the same as The crystal oscillator piece 73 has a convex lens-shaped cross section, and is bonded and fixed on the conductive holding member 35 by a conductive adhesive 36, as in the above-described embodiment.

According to this embodiment having such a configuration, the cap 71 and the hermetic base 40 are made of ceramics, and the cap 71 and the hermetic base 40 are bonded by the adhesive 75. Similar to the embodiment shown, the container 7 does not rust.
2 can be provided, and effects such as the rust resistance of the crystal oscillator 31 of this type can be significantly improved can be obtained. Moreover, in this embodiment, since the cap 71 is integrally formed in advance, there is no need to join the frame-shaped body 42 and the lid body 43, the number of assembling steps is reduced, and the productivity is improved.

FIGS. 8 to 10 show an embodiment of the second invention, and in the following description, parts corresponding to those of the first invention will be designated by the same reference numerals. In this embodiment, a hermetic base 6 made of ceramics
A container 62 is composed of 0 and a cap 61 made of metal such as iron, and the crystal oscillator piece 37 is hermetically sealed in the container 62. In the case of this embodiment, the inclined surface 60a is formed inside the upper side wall of the hermetic base 60. On the other hand, the cap 61 is formed in a substantially flat plate shape, but the peripheral portion thereof is
It is bent and formed corresponding to the shape of the upper side wall of the hermetic base 60.

The hermetic sealing of this embodiment is performed using solder. That is, on the upper side wall of the hermetic base 60,
As shown enlarged in FIG. 11, W, Mo or Ag / Pd
Of the metallized layer 6b is formed.
Solder 64 is arranged on 0b. Then, the packing 63 is arranged from between the inclined surfaces 60 a of the hermetic base 60 and the cap 61 toward the central portion of the cap 61. The packing 63 is made of, for example, a silicone resin, and is arranged over the entire circumference so that the solder 64 and the inside of the container 62 are blocked.

According to the present embodiment having such a configuration, the portion where the solder 64 is to be arranged by the packing 63 and the container 62 are arranged.
Since the interior is shut off, for example, when the solder 64 is melted by high-frequency heating, the gas of the flux becomes the container 6
(2) It does not enter the inside, and the adverse effect on the crystal oscillator piece 37 is prevented.

In the above embodiment, the inclined surface 60a is formed at the joint of the hermetic base 60 and the cap 61.
61a is formed, and the packing 63 is arranged from the portion sandwiched by the both inclined surfaces 60a, 61a toward the center, but the present invention is not limited to this, and for example,
As shown in FIG. 12, a flat cap 65 may be used, and the packing 63 may be arranged at the corner portion between the hermetic base 60 and the cap 61 without forming an inclined surface on the joint surface with the hermetic base 60. . In this case, as shown in FIGS. 13 and 14, the cap 65 may be provided with a step in either the upper or lower direction.

Further, the present invention is not limited to the above embodiments, and it is possible to combine the above-mentioned first invention and second invention. That is, for example, on the lower surface of the hermetic base 60 of the crystal unit shown in FIGS.
It is also possible to provide a protrusion 41 as shown in FIG. As described above, the present invention can be variously modified without departing from the spirit thereof.

[0038]

As described above, according to the first aspect of the invention, since a plurality of protrusions for forming a gap between the circuit board to be mounted and the circuit board are provided on the base, water or hot water can be obtained. Even when a cleaning liquid that is friendly to the environment is used, it is possible to obtain an effect that the flux adhered during soldering to the circuit board can be sufficiently removed.

Since the base and the cap are made of an insulating material such as ceramics, and the base and the cap are adhered to each other with an adhesive to hermetically seal, a container that does not rust is formed. Therefore, the rust resistance of this type of crystal unit can be significantly improved, and the insulating sheet used in the conventional metal hermetic base is not required, and the number of parts used can be reduced.

Further, in the second aspect of the present invention, since the packing for cutting off the portion where the solder is to be placed from the inside of the container is provided at the joint between the base and the cap, the flux of The effect that the gas can be prevented from entering the container to prevent the crystal oscillator piece from being adversely affected.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a crystal resonator according to the first invention.

FIG. 2 is a bottom view of the same.

FIG. 3 is a side view showing a cross section of the same cap.

FIG. 4 is a configuration diagram showing another embodiment of the crystal unit according to the first invention.

FIG. 5 is a constitutional view showing still another embodiment of the crystal unit according to the first invention.

FIG. 6 is a constitutional view showing still another embodiment of the crystal unit according to the first invention.

FIG. 7 is a plan view of the same.

FIG. 8 is a configuration diagram showing an embodiment of a crystal resonator according to the second invention.

FIG. 9 is a plan view of the same.

FIG. 10 is a vertical sectional view of the same.

FIG. 11 is a configuration diagram showing an enlarged main part of the same.

FIG. 12 is a configuration diagram showing a main part of another embodiment of the crystal resonator according to the second invention.

FIG. 13 is a configuration diagram showing an essential part of still another embodiment.

FIG. 14 is a configuration diagram showing a main part of still another embodiment of the present invention.

FIG. 15 is a configuration diagram of a crystal resonator according to a conventional example.

FIG. 16 is a configuration diagram of a crystal resonator according to another conventional example.

[Explanation of symbols]

 32, 40, 50, 60 Hermetic base 32a Flange portion 33 Through hole 34 Lead wire 35 Holding member 37, 73 Crystal resonator piece 38, 61, 65, 71 Cap 38a Flange portion 39, 41, 51 Protrusion 60a, 61a Inclined surface 60b Metallized layer 62, 72 Container 63 Packing 64 Solder 74 Recessed portion 75 Adhesive P Circuit board

Claims (3)

[Claims] 1. A crystal unit in which a crystal unit held by a lead wire penetrating the base is hermetically sealed by the base and a cap, and a circuit board to be mounted on the base. A crystal resonator having a plurality of protrusions for forming gaps between the crystal resonators. 2. The crystal unit according to claim 1, wherein the base and the cap are made of an insulating material such as ceramics, and the base and the cap are bonded to each other with an adhesive. 3. A crystal resonator piece held by a lead wire penetrating the base is disposed inside a container constituted by the base and the cap, and a joint between the base and the cap is soldered. In a crystal unit hermetically sealed by means of a crystal vibration, a packing is provided at a joint between the base and the cap for cutting off a portion to be soldered from the inside of the container. Child.