JPH0115161Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention primarily relates to a feedthrough capacitor unit suitable for use in an antenna input circuit of a TV receiver.

In TV receivers, in order to prevent image disturbances such as ghosts and reflected images caused by the reflection of signal radio waves, improve transmission efficiency, and prevent back-and-forth reflections of signals on feeder lines, the conventional method is shown in Figure 1. An antenna input circuit unit has been used in which a coupling capacitor _C1 is connected to the center conductor of a coaxial cable, etc., and a bypass capacitor _C2 is connected to the outer conductor to pass unnecessary frequency signals.

However, in this conventional antenna input circuit unit, since capacitors C ₁ and C ₂ have lead wires,
Due to the inductance of the lead wire, VHF,
The disadvantages were that the frequency characteristics in the UHF band deteriorated, the reflection coefficient increased, and the lead inductance was large, making it difficult to match the characteristic impedance of the coaxial cable.

In order to eliminate this drawback, a feedthrough capacitor unit having the structure shown in FIG. 2 has been proposed. This feedthrough capacitor unit has one plate 1
An annular ceramic capacitor 7 having electrodes 5 and 6 around the through hole 4 opened on both sides is placed inside a shield case 3 formed in a box shape with a through hole 2 on the top. are fixed to the face plate 1 by means of soldering or the like so as to be in contact with each other, and the electrode 5 has a cylindrical internal terminal that penetrates through the through hole 4 of the ceramic capacitor 7 and through the through hole 2 of the shield case 3. 8 are fixed by means such as soldering to form a feed-through capacitor, and the ceramic capacitor 7 surrounded by the internal terminal 8 and the shield case 3 is filled with insulating resins 9 and 10. It is becoming.

Also, on one of the side plates of the shield case 3,
Connector 1 such as F-type plug connected to the TV receiver side
1 is attached, and a coupling capacitor 13 made of an RC composite component with a discharge gap or the like is connected between this connector 11 and a center conductor 12 penetrating into the internal terminal 8. The coupling capacitor 13 is housed in an internal space 14 above the ceramic capacitor 7 serving as a bypass capacitor.

Furthermore, the shield case 3 has a magnetic capacitor 7
Only the upper surface facing the face plate 1 to which the cover 1 is attached is open, and this opening is closed with a lid 15.

The above-described feedthrough capacitor unit eliminates lead inductance and at the same time provides a complete shielding effect, improving frequency characteristics and effectively preventing the entry of unnecessary radiation waves.

However, as mentioned above, the shield case 3 that houses the ceramic capacitor 7, the coupling capacitor 13, etc.
The structure of the face plate 1 which is the mounting surface of the ceramic capacitor 7
Because it has a structure in which only the side facing the surface is open, it is easy to install and assemble parts such as the ceramic capacitor 7, internal terminal 8, and coupling capacitor 13, as well as casting the insulating resin 9 and 10. The work must be carried out at the bottom of the cylindrical, deep and narrow internal space 14, which makes each of the above operations extremely difficult and has the drawback of lacking workability.

In addition, an internal terminal 8 attached to the ceramic capacitor 7
Since the direction of the coupling capacitor 13 and the direction of the connecting tool 11 are perpendicular to each other, it is difficult to connect the coupling capacitor 13.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a feedthrough capacitor unit that allows easy attachment of each component to a shield case, assembly, and wiring connection work.

In order to achieve this object, the present invention provides a feed-through capacitor unit in which a feed-through capacitor is attached to one side plate of a box-shaped shield case, wherein the shield case has a main body portion and a lid portion, and the main body portion has a face plate and one side plate facing the one side plate, the other three side faces are open, and the lid portion is attached to the main body portion so as to close the opening. It is characterized by the presence of

DESCRIPTION OF THE PREFERRED EMBODIMENTS The content of the present invention will be described in detail below with reference to the accompanying drawings, which are examples. FIG. 3 is an exploded front view of the feedthrough capacitor unit according to the present invention, with parts cut away, and FIG. 4 is a side view thereof. In the figures, the same reference numerals as in FIG. 2 indicate functionally identical components. As shown,
The shield case 3 is composed of a main body part 16 to which the ceramic capacitor 7 is attached, and a lid part 17 attached to the main body part 16.

The main body portion 16 has a face plate 1 on one side and a face opposite to the face plate 1 on which the ceramic capacitor 7 is attached.
8, 19 respectively, and the other three sides 20,
21 and 22 are openings without a face plate. With such a structure, it is necessary to assemble the ceramic capacitor 7 into the main body portion 16, solder the internal terminal 8 to the ceramic capacitor 7, and insulate the resin 9, 10.
The large openings 20, 21, 22 are used for casting, as well as wiring connection work for the coupling capacitor 13.
Since the work can be carried out through the machine, each of the above-mentioned works becomes extremely easy to perform, and work efficiency is improved.

In addition, in this embodiment, a connecting tool 1 is placed on the face plate 18 opposite to the face plate 1 on which the ceramic capacitor 7 is attached.
1 is installed. With this structure, the direction of the internal terminal 8 and the direction of the connector 11 are the same, so the coupling capacitor 13 is connected to the internal terminal 8.
Since the contact 23a of the connector 23 inserted therein can be connected in a straight line with the contact 11a of the connector 11, the wiring connection work becomes very easy. Furthermore, since it requires less space, it is easy to downsize. The connector 23 has a structure in which a spring contact 23a is built inside an insulating cylindrical body 23b.

The lid portion 17 is connected to the opening 2 of the main body portion 16.
Face plates 24, 25, 26 that close 0, 21, 22
has. Therefore, when this lid portion 17 is attached to the main body portion 16 as shown by arrow A, the opening 20,
21 and 22 are closed by face plates 24, 25, and 26 to form a box-shaped shield case.
Almost complete shielding effect can be obtained.

As described above, the present invention provides a feedthrough capacitor unit in which a feedthrough capacitor is attached to one side plate of a box-shaped shield case, wherein the shield case has a main body portion and a lid portion, and the main body portion is , has a face plate and one side plate facing the one side plate, the other three side faces are open, and the lid portion is attached to the main body portion so as to close the opening. Because of this feature, it is possible to provide a small and inexpensive feed-through capacitor unit that is easy to attach each component to the shield case, assemble, and connect wiring, and has a high shielding effect.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an antenna input circuit, Fig. 2 is a partially cut-out front view of a conventional feed-through capacitor unit, and Fig. 3 is an exploded partially cut-out front view of a feed-through capacitor unit according to the present invention. FIG. 4 is also a side view thereof. 1... Face plate, 3... Shield case, 5, 6...
... Electrode, 7 ... Ceramic capacitor, 8 ... Internal terminal, 16 ... Main body part, 17 ... Lid part, 18 ...
...Face plate, 19...Side plate, 20, 21, 22...
Openings, 24, 25, 26...Face plate of the lid portion.

Claims (1)

[Claims for Utility Model Registration] (1) In a feed-through capacitor unit in which a feed-through capacitor is attached to one side plate of a box-shaped shield case, the shield case has a main body portion and a lid portion, and the main body portion has a face plate and one side plate facing the one side plate, the other three side faces are open, and the lid portion is attached to the main body portion so as to close the opening. A feed-through capacitor unit characterized by: (2) The feed-through capacitor unit according to claim 1, wherein a connecting tool is attached to a face plate opposite to the one face plate.