JPS641788Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a case for housing a high frequency device, such as a SAW filter.

Conventionally, when mounting a case with a built-in high-frequency device on a printed circuit board, etc., a bolt was made to protrude from the bottom of the case in order to prevent direct waves between the input and output terminals on the outside of the case as well as inside the case. This has been tightened with a nut through the printed board, or a metal plate has been fixed to the bottom of the case and protruded through the printed board.

However, the former method not only does not have a sufficient shielding effect, but both methods require a large number of man-hours to manufacture the case and are expensive.

The present invention was made in order to eliminate the drawbacks of the conventional method of shielding direct waves between input and output terminals outside the case as described above. A case for a high frequency device that has a high shielding effect between input and output terminals outside the case and is inexpensive, by molding the input and output terminals into a shape such that the parts of the input and output terminals that protrude outside the case block each other's line of sight. The purpose is to provide the following.

Hereinafter, the present invention will be explained in detail based on drawings showing embodiments.

FIGS. 1 and 2 are a sectional view and a bottom view showing an embodiment of the high frequency device case according to the present invention.

In both figures, a base 1 made of press-molded metal sheet is projected outward from the case at the center of its bottom, and a high frequency device, for example, a SAW filter 3 is fixedly housed inside the projection 2.

Further, circular recesses 5 to 8 of appropriate size are provided at the four corners of the base 1, and the SAW is placed in the recesses.
Input/output terminals 9 to 12 for electrically connecting the filter to the outside of the case are inserted through the base 1, and the base 1 is inserted into the recesses 5 to 8.
In order to maintain electrical insulation and airtightness between the terminals 9 to 12, for example, cover glass 13 to 16 is filled and melted to fix the terminals.

On the other hand, in order to seal the SAW filter 3 housed in the base 1 in a vacuum or inert gas atmosphere, a lid 17 is placed over the SAW filter 3, and the contact portion with the base 1 is sealed by soldering, cold pressure welding, or the like. Further, a recessed portion 18 is provided in the center of the lid 17 to block the mutual visibility of the tips of the input/output terminals 9 to 12 inside the case.

The above-mentioned case may be manufactured by compression molding a relatively thick metal plate as the base 19 into the shape shown in FIG. 3.

FIG. 4 shows a state in which the high frequency device case constructed as described above is mounted on a printed board.

That is, a hole suitable for fitting the protrusion 2 of the base 19 is provided at a predetermined position of the printed board 20,
The bottom surface of the protrusion 2 is made to protrude a little more than the back surface of the printed board 20.

Further, the input/output terminals 9 to 12 are connected to through holes 21, 22, . . . formed in the printed board 2.
Conductive pattern 23, 2 printed on the substrate through
Since the terminals 4, . . . are connected with solders 25, 26, .

In the case mounted in this manner, the protruding portion 2 formed on the bottom of the base 1 or 19 provides a line of sight between the tips of the input/output terminals 9 to 12 that slightly protrude from the back surface of the printed board 20. Since it has sufficient depth to interrupt, direct waves between the terminals are absorbed by the bottom of the base, and the current generated here can be completely blocked by grounding via the case ground. It is.

Note that direct waves between the tips of the terminals inside the case can also be blocked by the recessed portion 18 provided at the center of the lid 17.

Since the present invention is constructed as explained above, SAW
It is highly effective in blocking direct waves between the input and output terminals of high-frequency devices such as filters, and its characteristics,
That is, a filter is extremely effective in preventing waveform disturbance and reduction in attenuation.

Further, the manufacturing process for the case is exactly the same as that for manufacturing cases for conventional crystal resonators, etc., and there is no need to add any special process, so it can be implemented at extremely low cost.

[Brief explanation of the drawing]

1 and 1 are an AA cross-sectional view and a bottom view showing an embodiment of the high-frequency device case of the present invention, respectively, and FIG. 3 is a cross-sectional view showing another embodiment of the present invention,
FIG. 4 is a sectional view showing the case shown in FIG. 3 mounted on a printed board. 1, 19...Base, 3...High frequency device,
9 to 12...Input/output terminals.

Claims (1)

[Scope of utility model registration request] In a case in which an input/output terminal is provided on a good conductor base and is electrically insulated from the base and passes through the base in an airtight manner, and a high frequency device is stored in a space constituted by the base and a lid that hermetically seals the base, the above-mentioned A case for a high-frequency device, characterized in that a part of the outer bottom surface of the base is formed into a convex shape so as to prevent mutual visibility of the connection part between the input/output end and the external circuit pattern.