JPH0837439A - Piezoelectric vibrator, piezoelectric vibrator chip and piezoelectric oscillator - Google Patents

Abstract

PURPOSE:To obtain the piezoelectric oscillator by which the support of the piezoelectric vibrator is facilitated and in which the frequency hardly changes by applying electrolytic plating to a case whose air-tight terminal with a non-circular cross section and with a collar and whose opening are chamfered, fixing a piezoelectric vibrator to a flat inner lead and sealing the case with laser welding. CONSTITUTION:An inner lead 3 of an air-tight terminal 1 whose cross section is non- circular is formed to be flat. A collar 2 is formed to the terminal 1 to receive a case 7. A chamfer is provided to the collar 2 whose side received the case 7 through press forming. Thus, an opening of the case 7 is chamfered so as to prevent a gap from being increased when the case 7 is pushed in. An electrode 5 is vapor-depositted to a front side and a rear side of a piezoelectric oscillator chip 4. The oscillator chip 4 is fixed by cantilever by using a conductive adhesives or the like to the inner lead 3 of the air-tight terminal 1. Then the frequency is adjusted and the case 7 is pushed in and welded under nitrogen or vacuum environment by a laser or the like, and the piezoelectric vibrator 8 is obtained through air-tight sealing. A kovar or a Fe-Ni allay or the like is adopted for a metal of an outer circumferential part including the collar 2 of the terminal 1 and Ni plating or the like is applied to the surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibrator, a chip type piezoelectric vibrator and a piezoelectric oscillator.

[0002]

2. Description of the Related Art FIG. 1 is a plan view showing a conventional piezoelectric vibrator.
0 will be described with reference to the top view. A support spring 53 for fixing the piezoelectric oscillation piece 54 is fixed to the inner lead 52 of the airtight terminal 50 having a brim 51 on the outer circumference by welding or the like.

An electrode 55 is formed on the piezoelectric oscillation piece 54 by using a method such as vapor deposition.

The piezoelectric oscillation piece 54 is fixed to the support spring 53 with a conductive adhesive 56. Then adjust the frequency,
The case 57 was covered, and the piezoelectric vibrator 58 was sealed by resistance welding or the like in nitrogen or the like. FIG. 11 shows a plan view in which a conventional piezoelectric vibrator is mounted on a substrate.

When the piezoelectric vibrator 58 is mounted on the substrate 59 as a surface mounting component, the piezoelectric vibrator 58 tilts because of the flange 51 of the piezoelectric vibrator 58. Therefore, the metal holder 60 is mounted on the case 57 and then fixed on the substrate 59. Was.

As the chip-type piezoelectric vibrator, there are a chip-type piezoelectric vibrator which does not use a metal case and a hermetically sealed terminal and in which a piezoelectric oscillation piece is sealed with resin, and which is placed in a ceramic package (not shown).

The oscillator was produced by fixing an IC (integrated circuit) and a piezoelectric vibrator to a lead frame, combining them, and sealing the whole with resin (not shown).

[0008]

However, in the prior art, it is necessary to attach a support spring to the inner lead of the airtight terminal in order to support the piezoelectric oscillation piece on both sides, which increases the cost of the airtight terminal. . Further, there is a troublesome work of inserting the piezoelectric oscillation piece between the support springs.

Due to the support of both ends, the piezoelectric oscillation piece is distorted at the time of sealing and the frequency is easily changed.

When a conventional piezoelectric vibrator is mounted on a substrate as a surface mounting component, another holder must be mounted, which is a factor of increasing man-hours and cost.

Therefore, an object of the present invention is to provide a piezoelectric vibrator which is easy to support the piezoelectric oscillation piece, is hard to change the frequency, and is suitable as an inexpensive surface mounting component. A further object of the present invention is to provide a chip type piezoelectric vibrator and a piezoelectric oscillator using this piezoelectric vibrator.

[0012]

Therefore, the present invention solves such problems. (1) The piezoelectric vibrator of the present invention is hermetically sealed using a hermetic terminal and a case having a non-circular cross section. In the piezoelectric vibrator, the case having a chamfered opening is fitted into the airtight terminal with a brim, and the brim and the end of the opening of the case are welded and hermetically sealed. Is characterized by.

(2) Further, in the piezoelectric vibrator of (1), the base material of the airtight terminal or the case is any one of Kovar, Fe-Ni alloy and SUS, and the airtight terminal or the case. The surface of is subjected to electrolytic plating treatment.

(3) Further, in the piezoelectric vibrator of (2), the electrolytic plating treatment is electrolytic Ni plating treatment or Au plating treatment on the electrolytic Ni plating treatment.

(4) Further, in the piezoelectric vibrator of (1), the piezoelectric vibrating piece is fixed to the airtight terminal by cantilever support using a conductive adhesive.

(5) Furthermore, in the piezoelectric vibrator of (1), the shape of the lead of the airtight terminal for fixing the piezoelectric vibrating reed is flat. .

(6) Further, in the piezoelectric vibrator of (1), the ratio of the short side to the long side of the cross section is set to 3/5 or less and 2/5 or more.

(7) The chip type piezoelectric vibrator of the present invention comprises:
The piezoelectric vibrator of (1) is resin-sealed to form a chip component.

(8) The piezoelectric oscillator of the present invention is characterized by combining the piezoelectric vibrator of (1) and an IC (integrated circuit).

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

[Embodiment 1] An embodiment of the present invention will be described with reference to the plan view of FIG. 1 and the sectional view of FIG.

The inner lead 3 of the airtight terminal 1 having a non-circular cross section is formed by flattening.

The airtight terminal 1 is formed with a collar 2 and a case 7
It is designed to receive

When the brim 2 is molded, R is attached to the receiving side of the case 7 because it is molded by pressing.

Therefore, when the case 7 is pushed in, the case 7
The opening of the case 7 is chamfered so that the gap between the collar 2 and the collar 2 does not become large.

The chamfering may be R chamfering or C chamfering as long as it is larger than R of the brim 2.

In this way, when the case 7 is pushed into the airtight terminal 1, the gap between the brim 2 and the case 7 can be minimized.

Electrodes 5 are formed on the front and back sides of the piezoelectric oscillation piece 4 by means of vapor deposition or the like.

The piezoelectric oscillation piece 4 is fixed to the inner lead 3 of the airtight terminal 1 in a cantilevered manner using a conductive adhesive 6 or the like.

After that, the frequency was adjusted, and the case 7 was pushed in and welded in a nitrogen atmosphere or in a vacuum by a laser or the like to hermetically seal the piezoelectric vibrator 8.

When laser welding, case 7 and collar 2
A laser beam is applied aiming at the contact portion of and the welding is performed while rotating the case 7.

The outer diameter of the brim 2 is set to be equal to or smaller than the outer diameter of the case 7 so that the case 7 is not welded after welding.
Be sure not to exceed the outer diameter of the.

FIG. 3 is a plan view showing the piezoelectric vibrator of the present invention mounted on a substrate.

If the outer leads 10 of the piezoelectric vibrator 8 are bent in a hook shape and horizontally fixed on the substrate 11, they can be effectively used as surface mount components.

Since the brim 2 does not become larger than the outer shape of the case 7 as in the conventional case, it can be mounted on the substrate 11 as it is without attaching another holder.

The metal of the outer peripheral portion including the brim 2 of the airtight terminal 1 is made of Kovar, Fe--Ni alloy, SUS or the like in order to match the thermal expansion coefficient with the insulating glass 9 therein.

Then, the surface is electroplated and Ni plating or the like is used.

In order to improve the solderability of the outer lead 10 of the hermetic terminal 1, Au plating may be further applied to the entire hermetic terminal 1 on the electrolytic Ni plating.

The material of the case 7 has a thermal expansion coefficient close to that of the metal of the hermetic terminal 1.

Therefore, Kovar, Fe-Ni alloy, SU
Select from S etc.

Similarly, Ni plating or the like is performed on the surface by electrolytic plating. Further, Au plating may be applied thereon to reduce gas adsorption, reduce gas generation in the case after hermetically sealing, suppress frequency change, and provide the piezoelectric vibrator 8 with high accuracy.

For the plating of the case 7 and the hermetic terminal 1, a combination of electrolytic plating is good, and it is most suitable for hermetic sealing by laser welding.

In the combination of electroless Ni plating and electrolytic Ni plating, since the melting point of Ni is different, leakage occurs after sealing.

Further, the precipitation of P (phosphorus) contained in the electroless Ni plating causes a leak after welding, so that the combination of the electroless Ni plating is not good.

Therefore, when sealing by laser welding, N
In i plating, a combination of electrolytic Ni plating is preferable.

Since the piezoelectric oscillation piece 4 is fixed to the inner lead 3 by cantilever support, unlike the both-end support, the influence of distortion at the time of sealing is small, and the frequency change during and after sealing is also small.

Further, the long-term aging characteristics are also excellent.

The cross section of the piezoelectric vibrator 8 of the present invention is non-circular and has an oval shape as shown in FIG. 2, and the ratio of the short side to the long side is 3.
/ 5 or less, the short side was 2.0 mm, and the long side was 3.5 mm or less.

By setting the long side to 3.5 mm or less, the size is made smaller than the 4.5 mm of the piezoelectric vibrator of the ceramic package.

The lower limit of the long side is 2 m from the size of the piezoelectric oscillation piece 4.
m. If the width dimension of the piezoelectric oscillation piece 4 is reduced, the electrode dimension is also reduced, so that the resistance value (CI value) increases.
I can't show the characteristics.

The short side is set to 2.1 mm or less so that the thickness direction when the piezoelectric vibrator 8 is laid sideways is set to be 1.8 mm of that of the piezoelectric vibrator of the ceramic package.

It is difficult to manufacture the hermetic terminal 1 unless the lower limit of the short side is 2/5 or more of the long side.

Therefore, the ratio of the short side to the long side is 3/5 or less 2 /
The range is 5 or more.

Further, the shape of the inner lead 3 is made flat so that the case 7 is not touched even when the piezoelectric oscillation piece 4 is fixed.

For example, in the case of an AT oscillator, the piezoelectric oscillation piece 4 is thick because the thickness changes depending on the frequency.
The inner lead 3 is formed into a thin flat shape instead of a thick round lead (0.4 mm at 4 MHz) so that the piezoelectric vibrator 8 can have a thickness of 2.0 mm or less.

[Embodiment 2] FIG. 4 shows a sectional view of another embodiment of the present invention.

The piezoelectric vibrator 14 has a rectangular cross section of the hermetic terminal 12 and the case 13 and a square R.

Since the inner volume of the case 13 is large, the case 13 is not touched even if there is a variation in fixing the piezoelectric oscillation piece 4.

Further, since there is a straight line portion in the short side direction, it is easy to grasp and position.

[Embodiment 3] FIG. 5 is a sectional view of the piezoelectric vibrator of the present invention as a chip type piezoelectric vibrator, and FIG. 6 is a side view.

The outer leads 10 of the piezoelectric vibrator 8 are fixed to the lead frame 15, the whole is sealed with resin, and the lead frame 15 is bent to form a chip-type piezoelectric vibrator 16.

Although the cost is increased a little by sealing with a resin, the chip type facilitates the handling and provides compatibility with other ceramic package vibrators.

Since the piezoelectric vibrator 8 is thin, the chip type piezoelectric vibrator 16 is thin even if it is a chip type.

[Embodiment 4] FIG. 7 is a sectional view of a piezoelectric oscillator in which the piezoelectric vibrator of the present invention and an IC are combined, and FIG. 8 is a side view.

The IC has a function of outputting an oscillation frequency by incorporating an amplifier for oscillating the piezoelectric vibrator. If necessary, a frequency divider that divides the oscillation frequency and a P that multiplies
An LL (Phase Locked Loop) circuit and the like are built in.

The IC chip 18 is fixed to the lead frame 17, and the wire 19 is connected by wire bonding.

Next, the outer lead 10 of the piezoelectric vibrator 8
Is fixed to the lead raised from the lead frame 17 by welding or the like.

The outer leads 10 of the piezoelectric vibrator 8 may be bent and fixed to the lead frame 17.

At this time, the entire piezoelectric vibrator 8 may be fixed to the lead frame 17 so that the case 7 can be connected to the ground.

In this way, the piezoelectric vibrator 8 and the IC chip 18 are
The lead frame 17 connected to is set in a mold, epoxy resin or the like is poured, and the whole is sealed.

Then, unnecessary portions of the lead frame 17 are cut by a press and the outer leads are bent to form the oscillator 20.

Since the piezoelectric vibrator 8 is thin, it becomes thin as a whole even if it is overlapped with the IC 18, so that a small and thin piezoelectric oscillator 20 can be obtained.

[0073]

According to the present invention, an airtight terminal having a brim with a non-circular cross section and a case having a chamfered opening are each subjected to electrolytic plating, and a flat inner lead is supported by a cantilevered piezoelectric oscillation piece. By fixing and sealing by laser welding, the ratio of the short side to the long side of the cross section is 3/5 or less and 2.0 * 3.
A small and thin piezoelectric vibrator having a cross section of 5 mm or less becomes possible.

Also, since the airtight terminal does not have a support spring, the cost is low, and a holder is not required at the time of mounting on a substrate, and an inexpensive piezoelectric vibrator that can be mounted on a plane can be provided.

Furthermore, by fixing with cantilever support,
The piezoelectric vibrator is less affected by distortion at the time of sealing, has less frequency change, and has excellent long-term aging characteristics.

By attaching this piezoelectric vibrator to a lead frame and sealing it with resin, a small and thin chip-type piezoelectric vibrator can be obtained.

By combining the piezoelectric vibrator and the IC and sealing with a resin, a small and thin piezoelectric oscillator can be manufactured.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a sectional view of an embodiment of the present invention.

FIG. 3 is a plan view of the piezoelectric vibrator of the present invention when mounted.

FIG. 4 is a sectional view of another embodiment of the present invention.

FIG. 5 is a cross-sectional view of a chip-type piezoelectric vibrator of the present invention.

FIG. 6 is a side view of the chip-type piezoelectric vibrator of the present invention.

FIG. 7 is a sectional view of the piezoelectric oscillator of the present invention.

FIG. 8 is a side view of the piezoelectric oscillator of the present invention.

FIG. 9 is a plan view of a conventional piezoelectric vibrator.

FIG. 10 is a top view of a conventional piezoelectric vibrator.

FIG. 11 is a plan view of a conventional piezoelectric vibrator when mounted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Airtight terminal 2 ... Collar 3 ... Inner lead 4 ... Piezoelectric oscillation piece 5 ... Electrode 6 ... Conductive adhesive 7 ... Case 8 ... Piezoelectric vibrator 9・ ・ ・ Glass 10 ・ ・ ・ Outer lead 11 ・ ・ ・ Substrate 12 ・ ・ ・ Airtight terminal 13 ・ ・ ・ Case 14 ・ ・ ・ Piezoelectric vibrator 15 ・ ・ ・ Lead frame 16 ・ ・ ・ Chip type piezoelectric vibrator 17 ・..Lead frame 18 ... IC 19 ... Wire 20 ... Piezoelectric oscillator 50 ... Airtight terminal 51 ... Brim 52 ... Inner lead 53 ... Support spring 54 ... Piezoelectric oscillation piece 55 ... Electrode 56 ... Conductive adhesive 57 ... Case 58 ... Piezoelectric vibrator 59 ... Substrate 60 ... Holder

Claims (8)

[Claims] 1. A piezoelectric vibrator hermetically sealed using a hermetic terminal having a non-circular cross section and a case, wherein the case having a chamfered opening is fitted into the hermetic terminal having the collar, and the collar is fitted. A piezoelectric vibrator, wherein an end of the opening of the case is welded and hermetically sealed. 2. The hermetic terminal or the base material of the case is one of Kovar, Fe—Ni alloy and SUS, and the surface of the hermetic terminal or the case is electrolytically plated. The piezoelectric vibrator according to claim 1. 3. The piezoelectric vibrator according to claim 2, wherein the electrolytic plating treatment is electrolytic Ni plating treatment or electrolytic Ni plating treatment followed by Au plating treatment. 4. The piezoelectric vibrator according to claim 1, wherein the piezoelectric oscillation piece is cantilevered and fixed to the airtight terminal using a conductive adhesive. 5. The piezoelectric vibrator according to claim 1, wherein the shape of the lead of the airtight terminal for fixing the piezoelectric oscillating piece is flat. 6. The piezoelectric vibrator according to claim 1, wherein the ratio of the short side to the long side of the cross section is 3/5 or less and 2/5 or more. 7. A chip type piezoelectric vibrator, wherein the piezoelectric vibrator according to claim 1 is resin-sealed to form a chip component. 8. A piezoelectric oscillator comprising a combination of the piezoelectric vibrator according to claim 1 and an IC (integrated circuit).