JP2001111380A - Piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric device, especially, a crystal oscillator whose miniaturization can be promoted, and whose change characteristics in time can be made satisfactory. SOLUTION: In a piezoelectric device formed by sealing a crystal piece in a container itself constituted of laminated ceramics, a dent is formed on the edge face being the outer surface of the laminated ceramics constituted as at least a three-layer structure, and electrode terminals are formed on the edge faces of the upper and lower layers in the three layer structure while the edge face of the intermediate layer is used as a non-electrode, and the electrodes of a chip element are connected with the electrode terminals of the laminated ceramics, and the chip element is housed in the dent. Also, the piezoelectric device is formed as a crystal oscillator in which the IC chip is loaded on the container itself, and the chip element is formed as a by-pass capacitor between a power source and ground. Also, the piezoelectric device is formed as the crystal oscillator in which the IC chip is loaded on the container itself, and the chip element is formed as a high frequency coupling capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial technical field of a piezoelectric device enclosing a crystal piece, and more particularly to a method of mounting a chip element on a container body using a laminated ceramic and a surface mounting type crystal oscillator using the same. .

[0002]

2. Description of the Related Art Crystal oscillators are used as various frequency and time reference sources in various electronic devices including communication devices. In recent years, miniaturization has been promoted as typified by, for example, mobile phones, and further miniaturization has been demanded for the next generation.

(Example of Prior Art) FIG. 4 is a sectional view of a crystal oscillator for explaining a conventional example. The crystal oscillator is formed by accommodating a crystal blank 2, an IC chip 3, and a capacitor 4 (ab) in a concave container body 1 having a step, and joining a metal cover 5 by seam welding. The container body 1 is made of a laminated ceramic, and a metal ring 6 is soldered to the upper surface. The crystal blank 2 has one end portion of the extraction electrode extending from the excitation electrode fixed to the upper surface of the step portion with a conductive adhesive 7.

As shown by a dotted frame in FIG. 5, the IC chip 3 integrates circuit elements constituting a main part of an oscillation circuit.
Then, it is fixed to the bottom surface by face-down bonding. In the figure, reference numeral 8 denotes an amplifier, C1 and C2 denote oscillation capacitors, C3 denotes a bypass capacitor between a power supply and ground, C4 denotes a coupling capacitor that sends a high-frequency output (oscillation output) to the next stage, and 2A denotes a crystal oscillator. , R are resistors, Vcc is a power supply, and Vo is an output.

[0005] The capacitor 4 (ab) is the bypass and coupling capacitors C3 and C4, and the IC chip 3
Are arranged on both sides. Note that these capacitors 4 (a
b) has a larger capacitance (about 10,000 pF) than the oscillation capacitors C1 and C2 and is difficult to integrate.
It is in a situation where it has to be accommodated separately from the C chip 3.

[0006]

[Problems to be Solved by the Invention]
However, in the crystal oscillator having the above configuration, the bottom area in the concave portion is reduced with further miniaturization, and the capacitor 4
The space accommodating (ab) is damaged. Further, since a plurality of components of the IC chip 3 and the capacitor 4 (ab) are accommodated, there is a problem that the arrangement of the elements and the electrode patterns are complicated, and mounting by an automatic machine is difficult.

A capacitor 4 (a) is used together with the crystal blank 2.
Since b) is arranged in the same space, the amount of the conductive adhesive 7 for fixing them is increased. Therefore, there is also a problem that the aging characteristics are deteriorated by the gas or the like released from the conductive adhesive 7. In particular, a problem requiring a high degree of stability, such as a temperature-compensated oscillator, becomes serious.

(Object of the Invention) It is an object of the present invention to provide a piezoelectric device, particularly a crystal oscillator, which promotes miniaturization and has good aging characteristics.

[0009]

According to the present invention, a multilayer ceramic as a container body has at least a three-layer structure, and a recess is provided on an end face (side face) serving as an outer surface of the multilayer ceramic, and an end face of an intermediate layer is formed as an electrode-less upper face. The basic solution is to form an electrode terminal connected to the electrode of the chip element on the end surface of the lower layer.

[0010]

In the present invention, since the recess having the electrode terminal is provided on the side surface of the multilayer ceramic, the chip element is housed outside independently of the crystal blank. Further, since the chip element can be mounted in the vertical direction, the plane area of the container body is reduced. Hereinafter, an embodiment of the present invention will be described.

[0011]

1 to 3 are views for explaining an embodiment of the present invention. FIG. 1 is a half sectional view of a crystal oscillator, FIG. 2 is an enlarged view of the same part, and FIG. 1 is an exploded view of FIG. The same parts as those in the prior art are denoted by the same reference numerals, and description thereof will be simplified or omitted. As described above, the crystal oscillator is formed by accommodating the crystal blank 2 and the IC chip 3 in the concave container body 1 in the container body 1 and joining the metal cover 5 by seam welding. Then, the condenser 4 (ab) is connected to the container body 1.
Is housed in a concave depression 9 provided on the side surface of the outer surface of the. In this embodiment, the container body 1 includes a bottom wall 10 and first and second containers.
It is made of a laminated ceramic having frame walls 11 and 12. The metal ring 6 is soldered on the second frame wall 12, and the metal cover 5 is joined by seam welding.

The first frame wall 11 includes an intermediate layer 11a and upper and lower layers 11a.
(Bc) The three-layer structure is adopted. The pair of opposing sides has concave portions on both side surfaces, and the intermediate layer 11a has no electrodes, and the electrode terminals 13 (ab) are formed on the upper and lower layers 11 (bc). These are formed in a single-layer state by forming a base electrode by printing, for example, by laminating after lamination, and so-called through-hole processing. The bottom wall 10 has an electrode pattern electrically connected to the electrode of the crystal blank 2 and the IC chip 3, and mounting electrodes connected to the electrode pattern and extending to the side surface and the back surface through through holes and the like (not shown). Illustrated).

Then, a capacitor 4 composed of a chip element
The mounting electrode 14 (ab) of (ab) is recessed into the electrode terminal 1 of
3 (ab) is electrically connected and fixed by a conductive adhesive 7 (not shown). That is, the capacitor 4 (ab)
The vertical direction is the vertical direction, and the thickness direction with the smallest dimension is faced and accommodated. The capacitor 4 (ab) is connected to the bypass and coupling capacitors C3 and C4 as described above.
And

With such a configuration, since only the IC chip 3 is accommodated in the concave portion, the bottom area is kept small.
The arrangement of elements in the recess is simplified and mounting is facilitated. In addition, since the thickness direction in which the dimension of the capacitor 4 (ab) is the smallest is accommodated in the side surface of the outer surface, the overall planar outer dimension can be reduced. In addition, since the crystal blank 2 and the IC chip 3 are housed separately, the amount of the conductive adhesive 7 in the container is reduced, and the aging characteristic is favorably maintained.

[0015]

[Others] In the above embodiment, the condenser 4 (ab) for bypass and coupling is accommodated in the recess 9 of the container body 1. However, the present invention is not limited to this.
b) or chip elements such as resistors or inductors may be accommodated. Further, although the crystal oscillator has been exemplified, the invention can be applied to piezoelectric devices such as a piezoelectric vibrator, a filter element made of a piezoelectric material, and a surface acoustic wave element.

Although the capacitor 4 (ab) is accommodated in the depression 9, a part may protrude from the depression 9. Also,
The depressions 9 are formed on a pair of opposing side surfaces, but may be one or three or more as necessary. Although the laminated ceramic is formed from the bottom wall 10 and the first and second frame walls, basically, the intermediate layer 11a and the upper and lower layers 11 (bc) of the first frame wall 11 are formed.
Is a basic structure, and can be formed only by this. In addition, the depression 9 is formed in a concave shape, but any shape may be used as long as it can accommodate the capacitor 4 (ab). Although the cover is joined by seam welding, the cover may be joined by resin or glass.

In connection with the present invention, there is, for example, Japanese Utility Model Publication No. 7-35451 by the present applicant. This is an idea and is an idea. Is not specified,
In the present invention, this point can be realized in this case.

[0018]

According to the present invention, the laminated ceramic serving as the container body has at least a three-layer structure, and a recess is provided on an end surface (side surface) serving as an outer surface of the laminated ceramic. Since the electrode terminals connected to the electrodes of the chip element are formed, it is possible to provide a piezoelectric device, particularly a crystal oscillator, which promotes miniaturization and has good aging characteristics.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a crystal oscillator illustrating one embodiment of the present invention.

FIG. 2 is a partially enlarged view of a crystal oscillator explaining one embodiment of the present invention.

FIG. 3 is an exploded view of the container main body for explaining one embodiment of the present invention.

FIG. 4 is a cross-sectional view of a crystal oscillator illustrating a conventional example.

FIG. 5 is a schematic diagram of an oscillation circuit illustrating a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Container main body, 2 crystal pieces, 3 IC chips, 4 capacitors, 5 metal covers, 6 metal rings, 7 conductive adhesives, 8 amplifiers, 9 depressions, 10 bottom walls, 11 first frame walls, 11a intermediate layers, 11b Upper layer, 11c Lower layer, 12 Second frame wall, 13 Electrode terminal, 14 Mounting electrode.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H03H 9/10 H01L 41/08 D

Claims (3)

[Claims] 1. A piezoelectric device comprising a quartz body sealed in a container body made of a laminated ceramic, wherein the laminated ceramic has at least a three-layer structure, and a recess is provided on an end face which is an outer surface of the laminated ceramic, and An electrode terminal is formed on the end surface of the upper and lower layers without using the end surface of the intermediate layer of the structure as an electrode, the electrode of the chip element is connected to the electrode terminal of the laminated ceramic, and the chip element is housed in the recess. Piezo device. 2. The piezoelectric device according to claim 1, wherein said piezoelectric device is a crystal oscillator having an IC chip mounted on a container body, and said chip element is a bypass capacitor between a power supply and ground. 3. The piezoelectric device according to claim 1, wherein the piezoelectric device is a crystal oscillator having an IC chip mounted on a container body, and the chip element is a high-frequency coupling capacitor.