JPS5985122A - Piezoelectric oscillator - Google Patents

Abstract

PURPOSE:To reduce the manufacture cost by adopting an air-tight base made of an insulating base both sides of which a metallic layer is provided. CONSTITUTION:After a needle-shape terminal 41 is pressed into a through-hole 31 to a substrate [(a) is front side and (b) is back side], a metallic foil 32 and a head of a terminal 41 are soldered. A high temperature solder having >=300 deg.C of melting point is used as the solder. A piezoelectric element made of a crystal substrate provided with electrodes is mounted on the base obtained in this way. That is, the crystal plate 52 as the piezoelectric element is placed on the crystal base 51 and its electrode 53 is connected to the terminal 41 by a conductive adhesives 54. The piezoelectric element like this is mounted onto a lead 42 of the terminal by inserting a ring 62 made of a heat resistant and insulating resin such as ''Teflon'' or phenolic resin thereto and placing a solder sheet 71 for sealing. The oscillator assembled in this way is heated at about 200 deg.C in nitrogen environment so as to melt the sealing solder sheet 71 and the inner wall of a metallic can 61 and a metal foil 36 of the back side of the substrate are bonded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piezoelectric vibrator, particularly to the structure of a case that houses a piezoelectric element.

Conventionally, a piezoelectric vibrator such as a crystal is used as a highly stable vibrator, and therefore, the piezoelectric vibrator and the substrate are usually housed in a highly airtight case.

FIG. 1 shows the pressure side of T5+1 and the vibrator. In the figure, the case is made up of an airtight base 11 and a metal can 12, and after a piezoelectric element made of, for example, crystal is housed inside, it is evacuated and the airtight base 11 is placed in an atmosphere of nitrogen or an inert gas such as N2. The can 12 is joined by semi-EJ1t or resistance welding. As shown in FIG. 2, this airtight base 11 consists of a metal ring 21 forming the outer periphery, a metal terminal 22 penetrating through the center, and a glass portion 23 filling the space between them. Glass powder is press-molded in Zomuwe, and these are heated for 60 minutes in a reducing atmosphere.
It is made by heating the glass to 0-700℃ and melting it.

Therefore, it can be said that the airtightness is very high and the current quantity is also excellent.

However, since piezoelectric elements are inherently very stable, it is not necessary to use them all in a case with an airtight base made of glass. If not, it can prevent the silver electrodes normally used as electrodes from becoming sulfurized and deteriorating in quality, and also prevent the entry of significant moisture that can seriously affect the vibration of the crystal. There is no practical problem if it can be done.

The present invention has been made in view of these circumstances, and its purpose is to provide a piezoelectric vibrator that can significantly reduce manufacturing costs.

To achieve this object, the present invention uses an airtight base made of an insulating substrate with a metal layer on its surface.

Hereinafter, the present invention will be explained in detail using Examples.

Figure 3 shows a so-called print layout in which metal foil such as copper foil is provided on the surface of an insulating substrate made of resin such as phenol or epoxy! This is a board for use. FIG. 4A shows the inner surface when assembled as a case, and FIG. Regarding the surface, 32 is the metal foil part, 33 is the part where the metal foil is removed along the outer periphery to prevent electrical short circuits, and 34th is the part where the metal foil is removed to divide the metal foil part into two. It is. Also, regarding the back side, 35 is the part where the metal foil around the terminal through hole 31 has been removed, and 36 is the gold 8
This is the foil part. In addition, the same figure (c) is the actual MII of figure (b).
In this example, a solder resist 3γ is applied to the peripheral edge 38 of the metal foil 36 of the insulating plate to prevent solder from flowing.

After a nail-shaped terminal 41 is press-fitted into the through hole 31 of such a board as shown in FIG. 4, the metal foil portion 32 and the head of the terminal 41 are bonded together with solder. At this time, high-temperature solder with an RPTP point of 300°C or higher was used, and it was uniformly IFed using an automatic soldering device 1T.

Also, the solder should be applied to the entire metal foil part. This has the effect of increasing the heat capacity of the substrate surface and preventing the solder on the surface from melting even if the lead portion 42 of the terminal is heated later when the piezoelectric vibrator is soldered to an external device.

A piezoelectric element formed by attaching electrodes to a quartz crystal substrate, for example, is mounted on the Ve base thus obtained.

For example, as shown in FIG. 5, a crystal plate 52 as a piezoelectric element is placed on a crystal substrate 51, and its electrode 53 is connected to the terminal 41 using a conductive adhesive 54.

The purpose of interposing the crystal substrate 51 here is to prevent the effects of heat transmitted from the outside through the terminals 41 and distortion due to differences in expansion coefficients from directly affecting the crystal plate 52.

Figure 6 shows how the base on which such a piezoelectric element is mounted is press-fitted into the gold J% ring 61.
A ring 62 made of heat-resistant and insulating resin such as Teflon or phenol is inserted into the lead portion 42 of the terminal, and a sealing solder sheet 71 as shown in FIG. 7 is placed thereon. The solder sheet 71 is formed by rolling solder into a sheet with a thickness of about 0.3 cm and cutting it out.
In order to avoid this, the hole T2 is made slightly larger than the outer diameter of the hole T2.

The vibrator thus set is heated to about 200° C. in a nitrogen atmosphere to melt the sealing solder sheet 71.
The inner wall of the metal can 61 and all five metal foil portions 36 on the back surface of the substrate are bonded and sealed. Another method is to apply a paste-like solder to the boundary between the substrate periphery 38 and the metal can 61 and heat and melt it, if the substrate shown in FIG. 3(c) is used. In this case, the solder does not flow out to the center of the board due to the resist 37.

By performing such sealing, it is possible to construct a piezoelectric vibrator equipped with an airtight case that causes no problems in normal use. In other words, although the board that makes up the airtight base is made of resin such as phenol or epoxy, most of its front and back surfaces are made of gold, which is the most reliable airtight material, and the terminals and board , and the sealing between the board and the metal can is also done with solder, l', ii
j degrees etc. are perpendicular to the substrate: zl(L L'+1(
It depends on what 71 people do. In this way, as mentioned above, sufficient reliability can be obtained for practical use, but even more thorough measures must be taken as a countermeasure against the hygroscopicity of the resin. Regarding the metal foil removed portion 35 on the back side of the substrate, it is also possible to apply water silicone or the like.

FIG. 8 shows an example in which an insulating plate 81 made of heat-resistant resin and provided with two through holes into which two terminals are inserted is used instead of the insulating ring 62 shown in FIG. In this case, since a groove 82 is formed between the metal can 61 and the insulating plate 81, ordinary filamentous solder is inserted into this groove 82 and heated Wj.
IN'! However, compared to the case shown in FIG. 6, the reliability of the cutter attachment is increased.

Also in this case, it is better to use an insulating substrate coated with the solder resist No. 31f4(c) so that there is no fear that the solder will flow between the metal foil 36 and the dead plate 81. 27": Figure 91 shows the cross-sectional structure after sealing in this case. The metal can 61 has a flesh) Phi of 0.15, and the airtight base
The insulating substrate 91 has a thickness of 1. Oan, the thickness of the metal foil portion 92 is 0.05i++b, the diameter of the head of the terminal 41 is 2.5t=+h, the diameter of the lead portion 42 is 0.4-1, and the thickness of the insulating plate 81 is 0. 8 + rx. 93 is solder that adheres the terminal 41 to the metal foil portion 92;
4 shows solder that seals the inner wall of the metal can 61 and the gold foil portion 92. Here, arrow A (2) indicates the path of moisture intrusion, but it is not straight to the plate surface of the airtight base, but is rather close to parallel.If it is necessary to prevent moisture from entering, Water-repellent silicone or the like may be applied to the terminal surrounding portion 95 from which the metal foil has been removed.

In the above-mentioned embodiment, -C is the theory = Jt only for the case where the nail-shaped terminal 41 is used, but the present invention is not limited to this, and for example, as shown in FIG. It is also useful for practical use to mold the head to make it easier to mount the old Piezoelectric Suiko 1. In the illustrated example, the lead portion 102 has a round bar shape. However, the number of terminals is not limited to two, and a metal can can be used as one of the electrical terminals.
The present invention can be applied in exactly the same way to a device in which 91 pieces are sufficient because the piezoelectric device is used as one piezoelectric device, or a device in which 3 or more pieces are provided to accommodate a plurality of piezoelectric elements.

The following explanation is based on the case where a so-called printed wiring board is used to form an airtight base, but an IT ceramic board may also be used as the insulating board. In this case, The metal layer can usually be formed by depositing (F-viradium, etc.) using screen printing and baking methods. If a ceramic substrate is used, it must be sealed in a vacuum because it is not breathable. is also possible.

However, if the usage environment is favorable, the metal layer 112 is coated only on the outer edge of the back surface of the airtight base insulating substrate 111 as shown in FIG. It is also possible to join the metal can with solder. In this case, insulating members such as the ring 62 and the insulating plate 81 can be omitted if the solder does not flow and short-circuit the terminals inserted into the through holes 113 and 114.

Furthermore, the same effect can be obtained even if the piezoelectric element is applied to a rectangular element with beveled ends on both ends as shown in Figure 10, or to a round plate shape, a square plate shape, or any other shape. It goes without saying that you can get it.

As explained above, according to the present invention, by using an airtight base made of a durable substrate with metal layers on both sides, a 1.E electric vibrator having practically sufficient performance can be produced at a low cost. Obtainable. Furthermore, since the airtight base and the metal can can be separated in large numbers at the same time in a heating furnace, productivity is excellent and it is extremely useful in practice.

[Brief explanation of the drawing]

FIG. 1d is a perspective view showing an example of a conventional piezoelectric vibrator. :I'y Figure 2 is a perspective view showing the airtight base, Figure 3 (,) is a plan view showing the insulating substrate constituting the airtight base in an embodiment of the present invention, and Figure (b) is a Similarly, the bottom view, Figure 3 (C) of the i issue, is the same bottom view of the other '5% M (H example, Figure 4 is the airtight base with the y/ν4 element inserted, Figure 5 is the piezoelectric element mounted L, Fig. 6 is a perspective view showing a metal ring with a metal ring attached, Fig. 7 is a perspective view showing a side half-shield 1.
Fig. 8 shows another example of sealing.゛j1 I will show you another example of ``Iji!'' Figure, 2+! : 11 r bone”-n”2 tL
1 is a bottom surface 1 illustrating another example of the structure of a flexible substrate. 31.113,114...gosi),',! -f- is inserted through hole, 32.36.92...gun λ・
]Shi [5 parts (metal layer), 33°34.35...
Gold JJ" i foil removed part (insulating substrate), 41.100.
... j'il: l child, 42, 102, meeting, pilgrimage part, 52... crystal plate (pressure 111. ze, six children), 53
” ” ” ” 'iij:ti'i(, b 1. a
*e *Kinru 4 Kan, 62@Q...zetsu((i ('
l-') ng (insulating member), 71...Half day-1 sheet for sealing, 81...Insulating plate (insulating (ηIS utilization 9)
．． 91,111... Absolutely H-resistant substrate, 101...
pressure'ii cord, 112...metal layer. Patent applicant: Yanseki Co., Ltd. Agency: Masa Yamayo i1t't4 (ζgo・1 person) Figure 1
Figure 2 Figure 3 Figure 4 Figure 5 Figure 8 Figure 9 Figure 10 Figure 1zIIJ

Claims (1)

[Claims] (In a piezoelectric vibrator in which a piezoelectric element in which an electric conductor 4\ is provided on a 1,1 piezoelectric substrate is housed in a case consisting of a metal can and an airtight base, the airtight base has metal layers on both sides. and a metal terminal inserted into a through hole provided in the insulating substrate and soldered to a metal layer around the through hole on one surface of the substrate Other side outside H
A piezoelectric vibrator characterized by having 8 layers of gold attached to the metal ring in the part. (2) A piezoelectric element with electrodes provided on a piezoelectric substrate is inserted into a piezoelectric device that is housed in a case consisting of a metal can and an airtight base, and soldered to the metal layer surrounding the large Yt hole on one side of the insulating substrate. a metal terminal, and an insulating member placed around the metal terminal on the other side of the insulating substrate,
A pressure 11° C. vibrator characterized in that the insulating substrate is joined to a metal can by soldering at a metal layer with an indentation on the outer edge of the other surface.