JPH09162686A - Surface acoustic wave device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the short circuit of a surface acoustic wave element and to improve its reliability by mounting a metallic cap at the opening part of a ceramic container storing the surface acoustic wave element and applying the coating of resin to the inside of the metallic cap. SOLUTION: A surface acoustic wave element 3 is stored in a ceramic container 2 which is sealed airtight by a metallic cap 1. The element 3 is adhered on the inner bottom surface of the container 2 and held there. Then the cap 1 placed at the upper part of the element 3 is partly coated with resin 5, so that a metallic plating scrap 4 does not drop from the cap 1. In such a constitution of a surface acoustic wave device, it is not always required to apply the coating of resin 5 on the entire surface of the cap 1 as long as the scrap 4 does not drop onto the element 3. Thus the metallic plating scrap,, etc.,, stuck to the cap 1 is covered with resin 5 and therefore the short circuit that is caused to a comb-line electrode by the drop of the scrap 4 can be prevented.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a surface acoustic wave device.

[0002]

2. Description of the Related Art A surface acoustic wave element is constructed by alternately arranging opposing comb-shaped electrodes 7a and 7b on a piezoelectric substrate 6 as shown in FIG.

[0003]

Usually, the distance between the comb-shaped electrodes 7a and 7b is as small as 0.5 .mu.m to 15 .mu.m, and since it is exposed on the piezoelectric substrate 6, minute metal scraps and the like are not formed. The conductive foreign matter is comb-shaped electrodes 7a, 7b
If attached on top, it will easily short circuit. For example, in the configuration of the conventional surface acoustic wave device as shown in FIGS. 3 and 4, when the metal plating scraps 4 attached to the metal cap 1 above the surface acoustic wave element 3 fall on the surface acoustic wave element 3. In some cases, the comb electrodes 7a and 7b are short-circuited. 2 is a ceramic container.

An object of the present invention is to prevent a short circuit between the comb-shaped electrodes due to the drop of the metal plating scraps or the like from the metal cap as described above.

[0005]

In order to solve the above-mentioned problems, the surface acoustic wave device of the present invention is one in which at least a part of the inside of a metal cap is coated with resin.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the structure of claim 1 of the present invention, since the metal plating scraps and the like attached to the metal cap are wrapped in the resin, it is possible to prevent the comb-shaped electrodes from being short-circuited by being dropped.

A surface acoustic wave device according to an embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show the structure of a surface acoustic wave device according to an embodiment of the present invention. In FIGS. 1 and 2, the surface acoustic wave element 3 is housed in an airtight seal with a metal cap 1 and a ceramic container 2, and is adhered and held on the inner bottom surface of the ceramic container 2. The metal plating scrap 4 in the enlarged view of FIG. 2 is originally attached to the metal cap 1, and the resin 5 is coated so that the metal plating scrap 4 does not drop from the metal cap 1.

The surface acoustic wave device configured as described above is intended to prevent the metal plating scraps 4 from dropping onto the surface acoustic wave element 3, and therefore the entire surface of the metal cap 1 is necessarily coated with the resin 5. It is not necessary to do so, and in some cases, a part of the metal cap 1 above the surface acoustic wave element 3 may be coated with the resin 4.

[0010]

As described above, according to the present invention, it is possible to realize a highly reliable surface acoustic wave device by preventing the surface acoustic wave element from being short-circuited due to the drop of metal plating scraps or the like generated from the metal cap.

[Brief description of the drawings]

FIG. 1 is a sectional view of a surface acoustic wave device according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of part A in FIG.

FIG. 3 is a sectional view of a conventional surface acoustic wave device.

FIG. 4 is an enlarged cross-sectional view of portion B in FIG.

FIG. 5 is a perspective view of a surface acoustic wave device.

[Explanation of symbols]

 1 Metal Cap 2 Ceramic Container 3 Surface Acoustic Wave Element 4 Metal Plating Scrap 5 Resin

Claims (4)

[Claims] 1. A surface acoustic wave device having a structure in which a surface acoustic wave element is provided in a ceramic container and a metal cap is attached to the opening of the container, and at least a part of the inside of the metal cap is coated with a resin. A surface acoustic wave device characterized in that 2. The surface acoustic wave device according to claim 1, wherein the resin is an epoxy resin. 3. The resin according to claim 1, which is a silicone resin.
The surface acoustic wave device according to. 4. The resin according to claim 1, which is a polyimide resin.
The surface acoustic wave device according to.