JPS5930525Y2 - Feedthrough capacitor unit - Google Patents

Description

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

One of the reception disturbances in TV receivers is video disturbances such as ghosts or reflected images caused by reflection of signal radio waves.

This is because there is a difference in signal strength, time, etc. between the signal coming from the receiving antenna and the signal that directly enters the receiver or the signal that reflects off buildings etc. and enters the antenna. , which is caused by overlapping images.

In addition, it is necessary to match the antenna input circuit in order to improve the transmission efficiency as much as possible and prevent round-trip reflection of the signal on the feeder line. In such areas, reception systems using common antennas are becoming widespread, and matching of antenna input circuits has become an even more important issue.

Therefore, as shown in Fig. 1, conventional antenna input circuit units have a configuration in which a coupling capacitor C1 is connected to the center conductor of a coaxial cable, and a bypass capacitor C2 is connected to the outer conductor for passing unnecessary frequency signals. It was used.

However, since the capacitors C1 and C2 of the conventional antenna input circuit unit have lead wires, the inductance of the lead wires acts, deteriorating the frequency characteristics of VHF and UHF frequencies and increasing the reflection coefficient. Since the impedance is large, there are drawbacks such as difficulty in matching the characteristic impedance of the coaxial cable.

In order to eliminate this conventional drawback, a feedthrough capacitor shown in FIG. 2 has been proposed.

This through-type container has through-holes 4 opened on both sides inside a cylindrical external metal fitting 3 having a through-hole 2 in a bottom part 1.
A flat ceramic capacitor 7 having a pair of electrodes 5 and 6 around the bottom part 1 is fixed so that the electrodes 6 are in contact with each other on the bottom part 1, and the electrode 5 is made to pass through the through hole 4 of the ceramic capacitor 7. A cylindrical internal terminal 8 was fixed thereto, and an insulating resin 9 was filled around the ceramic capacitor surrounded by the internal terminal 8 and the external metal fitting 3.

In order to configure a feed-through type capacitor unit for an antenna input circuit using the above-mentioned feed-through type capacitor, for example, as shown in FIG. A through-type capacitor S with screws 10 is provided inside a box-shaped shield case 11, and the shield case 11 and the through-hole type capacitor S are connected by a nut 12 screwed into the tip of the connecting body 10 to provide insulation that is better than Bakelite or the like. It is mounted on the board 13.

A connecting body 15 for connecting the coaxial cable 14 to the tuner is attached to the other face plate of the shield case 11, and a center conductor of the coaxial cable 14 introduced into the shield case 11 via the connecting body 15, An RC composite component 16 having a discharge gap d1 for lightning protection is connected between the through-hole type capacitor S and the connecting body 10.

As mentioned above, the conventional feed-through capacitor unit can directly connect the center conductor of the coaxial cable through an RC composite component with a discharge gear, etc., and also connect the feed-through capacitor S, which becomes the bypass capacitor C2.
Since it can be directly attached to the shield case 11, the lead inductance becomes very small, and it is possible to achieve good frequency characteristics and a very small reflection coefficient.

However, the feedthrough capacitor S and the shield case 11 are each separate, which has the disadvantage of requiring a large number of parts, making assembly difficult, and increasing costs.

In addition, since the structure is such that the feedthrough capacitor S is mounted inside the shield case 11, the shape of the shield case 11 becomes large, and if the shield case 11 is made smaller, the work of assembling the feedthrough capacitor S and the wiring work become easier. Since it becomes troublesome, there is also a drawback that there is a limit to miniaturization of the shield case 11.

The object of the present invention is to eliminate the above-mentioned conventional drawbacks, and to provide a feedthrough capacitor unit I that is compact and thin in overall shape, easy to assemble, and inexpensive.

In order to achieve the above object, the feedthrough capacitor unit according to the present invention is provided with a recessed step having a through hole and recessed from the outside to the inside on one side plate of a box-shaped shield case. A through-hole type capacitor having electrodes on both sides with a through hole is fixed in the part so that one of the electrodes is in contact with the outer surface of the shield case in the recessed step part,
The recessed part around the feed-through capacitor is filled with an insulating resin, and the center conductor of the coaxial connector inserted into the through hole of the feed-through capacitor and the center conductor of the coaxial connector mounted on the face plate of the shield case are The present invention is characterized in that a circuit component including a capacitor is connected between the center conductor of another coaxial connection body, and this circuit component is built in the shield case.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The content of the present invention will be specifically described below with reference to the accompanying drawings, which are examples.

FIG. 4 is a sectional view of the through-type container unit according to the present invention.

In the figure, 17 is a box-shaped shield case.

One side plate of the shield case 17 has a recessed stepped portion 1 that is recessed from the outside to the inside and has a through hole 18 in the center.
9 is provided.

Reference numeral 20 denotes a penetrating type container installed in the recessed step portion 19.

With this structure, since the feedthrough capacitor 20 is attached to the outside of the shield case 17, the feedthrough capacitor 20 can be very easily assembled into the shield case 17.

Further, since there is no need to provide a space inside the shield case 17 to accommodate the through-type container 20, the overall shape of the shield case 17 can be made thinner and smaller.

In this embodiment, the through-type capacitor 20 has a pair of electrodes 20b and 20C provided on two opposing surfaces of a dielectric ceramic 20H formed in a disk shape with a through hole 21, The electrode 20b is attached to the frame-shaped edge 19. of the recessed step portion 19. a, for example, by soldering or the like.

Therefore, in this embodiment, the shield case 17 is also used as the external terminal of the through-type capacitor 20, so the external terminal that was conventionally required is no longer required.
The number of parts is reduced, resulting in cost reduction and downsizing.

Reference numeral 22 denotes an internal terminal of the feedthrough capacitor 20, which is fixed to the electrode 20C of the feedthrough capacitor 20 by soldering or other means, and also passes through the through hole 21.18 of the feedthrough capacitor 20 to connect to the shield case 17. It is introduced from the outside to the inside.

The internal terminal 22 is formed into a stepped cylindrical shape having a large diameter portion 22 a and a small diameter portion 22 b.
The end face of the electrode 20C is fixed by soldering.

Moreover, inside the small diameter portion 22b of this internal terminal 22,
The connecting body 23 is inserted and attached.

This connecting body 23 has a contact portion 23a that is inserted into the inner diameter portion of the internal terminal 22, and an internal contact portion 23b that passes through the center portion.

The internal contact portion 23b is the large diameter portion 22 of the internal terminal 22.
The large diameter portion 22a forms a connector that is connected to an antenna-side connector (not shown).

24 is an insulating resin filled around the through capacitor 20 for the purpose of ensuring insulation properties, temperature resistance, etc.

Reference numerals 25 and 26 denote heat-resistant insulating tubes fitted around the outer peripheries of the large-diameter portion 22 a and the small-diameter portion 22 b of the internal terminal 22, and are made of a resilient heat-resistant insulating material such as silicone resin.

The insulating tubes 25 and 26 are provided so that their ends protrude from the surface of the insulating resin 24, thereby increasing the creepage distance between the internal terminal 22 and the shield case 17, which is the external terminal, and increasing the dielectric strength. It increases the voltage.

In addition, the insulating tubes 25 and 26 alleviate the stress that occurs when the insulating resin 24 hardens and shrinks or during a heat cycle test, and prevents gaps, cracks, or peeling from occurring between the through-type capacitor 20 and the internal terminals 22. It also has the function of

27 is the lid of the shield case, 28 is the coupling capacitor (
The capacitor C, ) in FIG. 1 can be constructed from an RC composite component with a discharge gear as shown in FIG.

Reference numeral 29 denotes a connector for connecting a coaxial connector led to a tuner of a TV receiver, etc., and is attached to the side surface of the shield case 17.

One end of the capacitor 28 connected to the internal contact portion 23 b of the connecting body 23 is electrically connected to the internal contact portion 29 a of the connecting body 29 .

As described above, in the feedthrough capacitor unit according to the present invention, a recessed step portion having a through hole and recessed from the outside to the inside is provided on one side plate of the box-shaped shield case, and the inside of the recessed step portion is recessed from the outside to the inside. A feedthrough capacitor having electrodes on both sides with a through hole is fixed so that one of the electrodes is in contact with the outer surface of the shield case in the recessed step, and The inside of the part is filled with insulating resin, and the center conductor of the coaxial connection body inserted into the through hole of the through-type condenser is connected to the center conductor of another coaxial connection body installed on the face plate of the shield case. Between,
Since the present invention is characterized in that a circuit component including a capacitor is connected and the circuit component is built in the shield case, the following effects can be obtained.

(1) Since the feed-through capacitor can be inserted into the recess from the outside of the shield case, the work of assembling the feed-through capacitor becomes easy and costs can be reduced.

(2) Since there is no need to provide a storage space for the through-type container inside the shield case, the overall shape of the shield case can be made smaller and thinner.

(3) As shown in the embodiment, since the shield case can also be used as the external terminal of the feedthrough capacitor, the number of parts, cost, and size can be reduced.

[Brief explanation of drawings]

Figure 1 is a TV antenna input circuit diagram, Figure 2 is a cross-sectional view of a conventional feed-through capacitor, Figure 3 is a cross-sectional view of a conventional feed-through capacitor unit using this feed-through capacitor, and Figure 4 is a diagram of the present invention. FIG. 3 is a sectional view of the feedthrough capacitor unit according to the present invention. 17... Shield case, 18... Through hole, 19... Recessed step, 20... Penetration type container, 21... Penetration Hole, 22...
...Internal terminal.

Claims (1)

[Scope of utility model registration request] A feed-through type capacitor in which a recessed step having a through hole and recessed from the outside to the inside is provided on one side plate of a box-shaped shield case, and electrodes are provided in the recessed step on both sides with the through hole opened. one of the electrodes is fixed so as to be in contact with the outer surface of the shield case in the concave step, an insulating resin is filled in the concave step around the feedthrough capacitor, and the through hole of the feedthrough capacitor is A circuit component including a capacitor is connected between the center conductor of the coaxial connection body inserted in the shield case and the center conductor of another coaxial connection body installed on the face plate of the shield case, and this circuit component is A feed-through capacitor unit built into the shield case.