JPH043610A - Vibrator - Google Patents

Abstract

PURPOSE:To obtain this inexpensive oscillator having high productivity and high reliability by welding a sealed vessel and a cap with glass and fixing only one end part in the longitudinal direction of a piezoelectric vibrating piece to the wiring pattern of the sealed vessel and providing this end fixing part with a groove. CONSTITUTION:In a vibrator (c) provided with a piezoelectric vibrating piece 16 fixed to the wiring pattern 15 of the sealed vessel 14, glass 20 is used as welding materials to weld the sealed vessel 14 and a cap 19, and only one end part in the longitudinal direction of the piezoelectric vibrating piece 16 is fixed to the wiring pattern 15 of the sealed vessel 14, and this end fixing part of the piezoelectric vibrating piece 16 of the sealed vessel 14 is provided with a groove 18. Since glass 20 is used as welding materials, the latch heat treatment is available, the productivity is improved more than seam welding. Since one end of the piezoelectric vibrating piece 16 is made free, the characteristic change is economically reduced; and since the one-end fixing part is provided with the groove 18, paste is not connected with the groove 18 while making the groove 18 as the boundary to prevent short-circuit of an electrode. Thus, the productivity is more excellent and the reliability is improved.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is applicable to devices that require time division, such as microcomputers, personal computers, video equipment, digital audio equipment, and digital communication fields. The present invention also relates to the structure of a vibrator that generates a fundamental frequency, and in particular to the structure of a leadless surface-mounted vibrator that uses a multilayer ceramic container and is compatible with small and thin designs.

(Conventional technology) FIGS. 5 and 6 are explanatory diagrams of conventional vibrators A and B.

In conventional example A shown in FIG. 5, 1 is a multilayer ceramic sealed container, 2 is a metal film pattern (shaded area) provided on the ceramic sealed container 1, 3 is a piezoelectric vibrating piece such as crystal, and 4 is a Ni plating. 5 is a conductive paste for fixing the piezoelectric vibrating piece 3 and the ceramic sealing container 1 and electrically connecting it to the metal film pattern 2; 6 is soldering to the ceramic sealing container 1; It is a Kovar ring (plated with Au).

Conventional example A is a type in which the metal cap 4 is sealed by seam welding on the Kovar ring 6, and the sealing is performed by rotating a parallel roller for seam welding (not shown) along the outer periphery. Kovar material, which has a coefficient of thermal expansion similar to that of ceramic, is generally used as the sealing material, and is plated with Au to improve weldability. The metal cap 4 is also made of Ni-plated Kovar material. Further, both ends of the piezoelectric vibrating piece 3 in the longitudinal direction are sealed to the ceramic sealing container 1 with a conductive paste 5.

In conventional example B shown in FIG. 6, 7 is a single-layer ceramic substrate, 8 is a metal film pattern provided on the ceramic substrate 7 (shaded area), 9 is a vibrating element made of crystal, etc., and 10 is a ceramic cap. , 11 is glass formed on the ceramic cap 10, 12 is a metal support for holding the piezoelectric vibrating piece 9 in a hollow state, and 13 is a conductive paste.

Conventional example B is a type in which a ceramic cap 10 with a glass 11 is placed on a single-layer ceramic substrate 7 and sealed by heat treatment. Piezoelectric vibrating piece 9 on single-layer ceramic substrate 7
Two metal supports 12 are fixed with conductive paste 13 in order to hold the metal supports 12 in a hollow state, and the piezoelectric vibrating piece 9 is fixed on top of the two metal supports 12 with conductive paste 13. Both longitudinal ends of this piezoelectric vibrating piece 9 are fixed with two metal supports.

(Problems to be Solved by the Invention) In Conventional Example A, only one seam welding parallel roller electrode (not shown) can be sealed while moving along the sealing portion. As a result, it is time consuming and unproductive.

Furthermore, in order to perform seam welding, the Kovar ring must be brazed to the multilayer ceramic sealed container, which increases the cost.

Conventional Example B has better productivity than Conventional Example A because it can be sealed by batch heat treatment in a furnace, but because it uses a single-layer ceramic substrate, it requires metal Support equipment is definitely required.

Since two more parts are added, the number of assembly steps is high, which is bad for productivity.

In addition, in both Conventional Examples A and B, both ends of the piezoelectric vibrating piece in the longitudinal direction are fixed, so that the difference in thermal expansion coefficient between the piezoelectric vibrating piece and the ceramic forming the sealed container becomes noticeable as stress. The surface mount type is mounted in a flow furnace, etc.
Since the temperature is raised to about 40 DEG C. to 270 DEG C. and the temperature is also raised during the heat treatment during the manufacturing process, cracks occur in the conductive paste over time, resulting in poor reliability.

(Means for Solving the Problems) The present invention provides a vibrator having the following configuration in order to solve the above problems.

The vibrator includes a sealed container provided with a conductive wiring pattern, a cap sealed to the sealed container, and a pressure t@ moving piece fixed to the wiring pattern of the sealed container, Glass is used as a sealing material for sealing the sealed container and the cap, and only one end of the piezoelectric vibrating piece in the longitudinal direction is fixed to the wiring pattern of the sealed container, and the piezoelectric vibrating piece of the sealed container is A vibrator characterized in that a groove is provided in a fixing portion at one end of a vibrating piece.

(Example) The purpose of the present invention is to obtain an inexpensive vibrator with high productivity and reliability.As will be described later, the specific sealing method is to heat a multilayer ceramic sealing container all at once. A glass sealing method that uses glass as the sealant is a processable sealing method. Furthermore, by using a multilayer ceramic sealing container, a metal support, which is necessary for a single layer ceramic substrate, is no longer required, and productivity is improved by combining the multilayer ceramic sealing container and glass sealing. Further, only one end in the longitudinal direction is fixed instead of fixing both ends in the longitudinal direction, where the difference in coefficient of thermal expansion tends to be noticeable. Furthermore, regarding the shape of the one-end fixing part of the multilayer ceramic sealed container, the present invention relates to a vibrator in which a groove is provided near the center to prevent a short circuit between the conductive paste and the two electrodes.

FIG. 1 is an explanatory diagram of the first embodiment of the vibrator according to the present invention, FIG. 2 is a cross-sectional view of the first embodiment, FIG. 3 is a cross-sectional view of the second embodiment of the present invention, and FIG. FIG. 2 is a partial perspective view of the first embodiment.

Examples will be described below.

The sealed container 14 made of multilayer ceramic material of the first embodiment C shown in FIGS.
is provided, forming a three-layer multilayer ceramic sealed container. A piezoelectric vibrating piece 16 made of crystal or the like has one longitudinal end fixed to a wiring pattern 15 provided in a sealed container 14 with a conductive paste 17. Sealed container 1
4 pressure @ The fixing part of the vibrating piece 16 is provided with a gap or step) 18, which separates one end of the vibrating piece 16 in the longitudinal direction into two places, and applies the pressure separately to the front and back electrodes of the piezoelectric vibrating piece 16. It is connected to. On the other hand, the ceramic cap 19 is formed to correspond to the sealed portion of the sealed container 14 or the glass 20 which is fired after applying frit glass melted with a solvent.

In the sealing method, a ceramic cap 19 with a glass 20 is mounted on a sealing container 14 in which a piezoelectric vibrating piece 16 is fixed at one end with a conductive paste 17, and the piezoelectric vibrating piece 16 is placed in a furnace in an inert gas such as N2. The glass 20 is heated to melt and seal it.

In the second embodiment shown in FIG. 3, a two-layer ceramic sealing container 21 is used, and one end of the piezoelectric vibrating piece 22 in the longitudinal direction is attached to the top layer of the sealing container 21 by a fi 23.
A conductive paste 24 is used to fix one end of the sealed container 21, which is divided into two parts. The ceramic cap 26 with the glass 25 has the cross-sectional shape shown in the figure to prevent the piezoelectric vibrating piece 22 and the conductive paste 24 from coming into contact with the cap 26.

Moreover, both of the first and second embodiments C and D have pressure! @ Moving piece 16
, 22 at one end in the longitudinal direction, the conductive paste 17, 24
The other end, which is not fixed by the metal film, is free and is simply brought into contact with the sealed container 14.21, and the one end 27 of the sealed container 14. Before the conductive paste 17.24 is hardened, the pressure serves to support the vibrating piece 16.22.

As mentioned above, in the oscillator using the multilayer ceramic sealing container of the present invention, by using glass for the multilayer ceramic sealing container and the sealing material, ■ - sealing by bulk heat treatment is possible; Two metal supports (for holding the piezoelectric vibrating piece in the air), which are indispensable for a ceramic substrate, can be omitted. In addition, by fixing only one end of the piezoelectric vibrating piece in the longitudinal direction and leaving the other end free, the thermal stress due to the difference in thermal expansion coefficient between the ceramic and the piezoelectric vibrating piece is reduced, causing cracks in the conductive paste. 0 surface mount type requires 230°C in a reflow oven etc. during mounting.
Although the temperature may be raised from ℃ to 270℃, the conductive paste is less likely to crack during the heat treatment process during the manufacturing process, so no stress is applied to the piezoelectric vibrating piece (
(It is well known that when stress is applied to a piezoelectric vibrating piece, its characteristics change.) Not only does the heat process described above not only cause no cracks, but the strain is released over time and the piezoelectric vibrating piece may break or break.
No deterioration of characteristics occurs. Furthermore, by providing a groove in the fixing part at one end of the multilayer ceramic sealed container, ■ short-circuits between the two electrodes of the piezoelectric vibrating piece can be prevented when applying conductive paste to the piezoelectric vibrating piece to fix it to the sealed container or when curing. This can be prevented (the conductive paste does not connect across I).

(Effects of the Invention) As described above, the vibrator according to the present invention has the following effects 1 to 3.

1. By using glass as the sealing material, it is possible to perform batch heat treatment compared to seam welding, which improves productivity, and compared to single-layer ceramic boards, single-layer boards require less metal support. Since two games are no longer necessary, productivity is further improved.

2. Because only one end of the piezoelectric vibrating piece in the longitudinal direction is fixed to the multilayer ceramic sealing container and the other end is left free, stress and dimensional changes due to the difference in thermal expansion coefficient between the piezoelectric vibrating piece and the ceramic are better than if both ends were fixed. The conductive paste is less prone to cracking even if the conductive paste is applied, and the properties change less over time (because distortion occurs when the conductive paste hardens) than when both ends are fixed, making it more reliable in terms of heat resistance. .

3. By providing a groove in the fixing part at one end of the multilayer ceramic sealed container, in order to fix the piezoelectric vibrating piece to the sealed container with the conductive paste, when applying the conductive paste, the paste does not come into contact with the groove as a boundary. Because the piezoelectric vibrating piece has two t[! This has the effect of preventing short circuits, improving productivity and yield.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the first embodiment of the vibrator according to the present invention, FIG. 2 is a cross-sectional view of the first embodiment, FIG. 3 is a cross-sectional view of the second embodiment of the present invention, and FIG. The partial perspective view of the first embodiment, FIGS. 5 and 6 are explanatory diagrams of the conventional vibrator AB. 1.14.21...Multilayer ceramic sealed container, 2.8
．． 15... Metal film wiring pattern, 3.9, 16.2
2... Piezoelectric vibrating piece, 4... Metal cap, 5.13, 17.24... Conductive paste, 6... Kovar ring, 7... Single layer ceramic substrate, 10.1
9.26...Ceramic cap, 11.20.25
...Glass, 12...Metal support, 18.23...
-Groove, 27... One end of the multilayer ceramic sealed container without metal film, A, B, C, D... Vibrator. Patent Applicant: Japan Victor Co., Ltd. Representative Kakiki
Japanese chart

Claims (1)

[Claims] A vibration device comprising a sealed container provided with a conductive wiring pattern, a cap sealed to the sealed container, and a piezoelectric vibrating piece fixed to the wiring pattern of the sealed container. In the child, glass is used as a sealing material for sealing the sealed container and the cap, and only one end in the longitudinal direction of the piezoelectric vibrating piece is fixed to the wiring pattern of the sealed container, and the sealing material is sealed. A vibrator characterized in that a groove is provided in one end fixing portion of the piezoelectric vibrating piece of the container.