JPH06132762A - Piezoelectric oscillator - Google Patents

Abstract

PURPOSE:To provide a piezoelectric oscillator which prevents short on account of contact between a metallic cap and an internal conductive material such as conductive paste and which can be miniaturized and lowered much more in height. CONSTITUTION:Terminal electrodes 11 and 12 are formed in a circle at the both end parts of a base substrate 10, and a piezoelectric ceramic element 15 is connected to the terminal electrodes 11 and 12 through conductive pastes 13 and 14. The metallic cap 16 provided with an insulating layer 17 at an inner surface is fitted on the base substrate 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric oscillator provided with a piezoelectric element.

[0002]

2. Description of the Related Art As a piezoelectric oscillator, for example, a ceramic oscillator includes a foot type and a surface mount type. The foot-type oscillator is tall and large in size due to its structure, and is not suitable for high-density mounting. A ceramic case or a resin case is generally used as the package for the surface mount type resonator, but the product becomes bulky due to the thickness of the package, and the product height is 2 mm or more depending on the type. It becomes a profile.

In addition to these types, there is a piezoelectric oscillator previously filed by the present applicant. This oscillator uses a metal cap (conductive cap) as a package in order to make the product a low profile. Due to the internal structure, the piezoelectric element is connected to the terminal electrode with a conductive resin paste or the like. There is. This structure has the advantage that the resonator can be made smaller and has a lower height. However, as the size and the height become smaller, the conductive resin paste easily comes into contact with the metal cap. It is necessary to make a large gap with the paste. However, if the space is left large, the package becomes large, which hinders further size reduction and height reduction.

FIG. 9 shows the structure of a piezoelectric oscillator using a metal cap. This oscillator includes a base substrate 30 and terminal electrodes 31, 32 formed on both ends of the base substrate 30.
, A piezoelectric element 35 connected to the terminal electrodes 31, 32 via conductive pastes 33, 34 on the base substrate 30, and a piezoelectric element 35 mounted on the base substrate 30.
And a metal cap 36 for protecting the.

[0005]

However, in the oscillator as shown in FIG. 9, if the metal cap 36 is made smaller and its height is made lower in order to further reduce the size and height, the metal cap 36 becomes smaller. In some cases, the metal cap 36 short-circuits the terminal electrodes 31, 32 by coming into contact with the conductive pastes 33, 34, and the function as a product may not be fulfilled.

Therefore, an object of the present invention is to provide a piezoelectric oscillator which can prevent a short circuit due to contact between a metal cap and an internal conductive material such as a conductive paste, and can further reduce the size and height. is there.

[0007]

In order to achieve the above object, the piezoelectric oscillator of the present invention is a piezoelectric oscillator using a conductive cap, and an insulating layer is provided on the inner surface of the conductive cap. It is characterized by that. In the oscillator of the present invention,
Since the insulating layer is provided on the inner surface of the conductive cap (generally a metal cap), even if the metal cap comes into contact with an internal conductive material such as conductive paste, the insulating layer interposed between the two will prevent A short circuit of the conductive material can be prevented. Therefore, the height of the metal cap can be made smaller than in the past, and the entire metal cap can be made smaller as a result, and the size and height of the product can be reduced.

As a material for the insulating layer, an insulating curable resin (for example, a thermosetting resin such as epoxy or an ultraviolet curable resin), a glass filler, or the like may be used.

[0009]

EXAMPLES The piezoelectric oscillator of the present invention will be described below based on examples. FIG. 1 is a plan view of the oscillator according to the embodiment.
2 is a bottom view, FIG. 3 is a sectional view taken along line AA of FIG. 1, and FIG. 4 is a sectional view taken along line BB of FIG.
The oscillator 1 is a surface-mount ceramic oscillator, and is different from that shown in FIG. 9 except that an insulating layer is provided on the inner surface of the metal cap.
The configuration is almost the same as that shown in. That is, the base substrate 1
Terminal electrodes 11 and 12 are formed in a spiral shape on both ends of 0,
On the base substrate 10, the piezoelectric ceramic element 15 is formed on the terminal electrodes 11 and 12 via conductive pastes 13 and 14, respectively.
And a metal cap 16 for protecting the ceramic element 15 is attached on the base substrate 10. An insulating layer 17 made of the material of the previous example is provided on the inner surface of the metal cap 16.

In such an oscillator 1, the metal cap 1
Since the insulating layer 17 is interposed between the conductive paste 13 and the conductive pastes 13 and 14, even if the metal cap 16 contacts the conductive pastes 13 and 14, the conductive pastes 13 and 14 are short-circuited, that is, the terminal electrodes 11 and 14. A short circuit of 12 can be prevented. Therefore, the height of the metal cap 16 can be further reduced. Further, in this example, the metal cap 16 overlaps with the terminal electrodes 11 and 12, but since the insulating layer 17 is present between the two, the terminal electrodes 11 and 12 at this location.
The short circuit of is also prevented.

Next, examples of a piezoelectric oscillator with a built-in capacitor are shown in FIGS. This oscillator 2 is structurally almost the same as that of the above-mentioned embodiment except that it is a surface-mounted ceramic oscillator having three terminals. 6 and 7, the terminal electrodes 21 and 22 are formed at both ends of the base substrate 20, and the terminal electrode 28 is formed at the center. Also in this oscillator 2, the insulating layer 27 is provided on the inner surface of the metal cap 26, and the metal cap 26 and the conductive pastes 23 and 24 are provided.
The insulating layer 27 prevents a short circuit due to contact with.
Of course, the metal cap 26 has the insulating layer 27 so that the terminal electrode 2
No contact with 1, 22.

[0012]

The piezoelectric oscillator of the present invention has the following effects because the insulating layer is provided on the inner surface of the conductive cap (metal cap) as described above. (1) Even when the metal cap comes into contact with the internal conductive material such as the conductive paste, the insulating layer is interposed between the two, so the metal cap does not directly contact the internal conductive material and the metal cap and the internal A short circuit due to contact with a conductive material can be prevented. (2) Since a short circuit due to contact between the metal cap and the internal conductive material can be prevented, the product can be further downsized and the height can be reduced (thickness of 1.0 mm or less). (3) The present invention can be applied not only to the surface mount ceramic resonator but also to a capacitor built-in surface mount ceramic resonator having three terminals.

[Brief description of drawings]

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

FIG. 2 is a bottom view of the oscillator shown in FIG.

3 is a cross-sectional view of the resonator shown in FIG. 1 taken along the line AA.

4 is a cross-sectional view of the resonator shown in FIG. 1 taken along the line BB.

FIG. 5 is a plan view of an oscillator according to another embodiment of the present invention.

6 is a bottom view of the oscillator shown in FIG.

7 is a cross-sectional view of the oscillator taken along line C-C shown in FIG.

8 is a cross-sectional view of the oscillator taken along line D-D shown in FIG.

FIG. 9 is a cross-sectional view of a main part of an oscillator according to a conventional example.

[Explanation of symbols]

 1, 2 Piezoelectric oscillator 10, 20 Base substrate 11, 12 Terminal electrode 15, 25 Piezoelectric ceramic element 16, 26 Metal cap (conductive cap) 17, 27 Insulating layer 21, 22, 28 Terminal electrode

Claims (1)

[Claims] 1. A base substrate, a piezoelectric element provided on the base substrate, a terminal electrode electrically connected to the piezoelectric element and led out to the outside, and a conductive member mounted on the base substrate and covering the piezoelectric element. A piezoelectric oscillator comprising a conductive cap, wherein an insulating layer is provided on an inner surface of the conductive cap.