JPH0617372Y2 - Jack device for video signal input of television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a video signal input jack device of a television receiver suitable for use in a small-sized television receiver.

[Outline of device]

The present invention is a video signal input jack device of a television receiver suitable for use in a small-sized television receiver, and the video signal input is switched from the built-in tuner side to the external device side when the plug is inserted. In this jack device, a jack for inputting a video signal of a television receiver is provided by providing a contact piece that is brought into conduction with the center conductor of the plug when the plug is inserted and a terminating resistor connected to the contact piece. The device is designed to be compact.

[Conventional technology]

Conventionally, some television receivers have a video signal input jack to which a video signal from an external video tape recorder or the like is supplied (Japanese Patent Laid-Open No. 61-88670). FIG. 6 is a diagram showing an example of a television receiver provided with this video signal input jack. In the figure, (10) shows the entire television receiver, and this receiver (10) is an antenna.
The radio signal received by (1) is supplied to the tuner (11), and the television broadcast signal of the desired station demodulated by the tuner (11) is supplied to the detection circuit (12). The television broadcast signal received by this detection circuit (12) is separated into a video signal and an audio signal, the audio signal is supplied to the audio circuit (13), and the speaker (14) connected to the audio circuit (13) is used. Output audio.

Then, the video signal output from the detection circuit (12) is supplied to the fixed contact piece (16a) of the jack (16) through the capacitor (22) having a capacity of about 1000 μF for removing the direct current component. This jack
(16) is an external video signal input terminal to which the video signal from an external video device such as a video tape recorder is supplied by inserting the plug (2) .It is a fixed connection when the plug (2) is not installed. The piece (16a) is in contact with the movable contact piece (16b).
When the plug (2) is inserted into the jack (16), the tip (2a), which is the conductor at the tip of the plug (2), comes into contact with the movable contact piece (16b), and this contact causes the movable contact piece (16b). 16b) is pushed up in the direction indicated by arrow A, the movable contact piece (16b) separates from the fixed contact piece (16a), and the fixed contact piece (16a) and the movable contact piece (1
6b) is no longer in contact with. Note that the plug
The sleeve (2b), which is a conductor provided concentrically with the tip (2a) of (2), comes into contact with a predetermined grounded contact piece (not shown) in the jack (16) to be grounded. I am doing it.

The movable contact piece (16b) is connected to the video processing circuit (18), and the video signal obtained at the movable contact piece (16b) is transferred to the video processing circuit.
Supply to (18). Further, the movable contact piece (16b) is grounded via a terminating resistance 75Ω resistor (17). Then, the video signal supplied by the video processing circuit (18) is converted into a primary color signal, and the converted primary color signal is supplied to the liquid crystal display (19).

By doing this, the movable contact piece (1
The image by the image signal obtained in 6b) is displayed on the liquid crystal display
Displayed in (19). That is, in the state where the plug (2) is not connected to the jack (16), the fixed contact piece (16a) and the movable contact piece (16a) are
Since it is in contact with b), the video signal of the television broadcast signal received by the tuner (11) is supplied to the video processing circuit (18) via the jack (16), and the image of this television broadcast is received by the liquid crystal display. Done on the display (19). Also, a plug to which the video signal from the video tape recorder is supplied.
When the (2) is connected to the jack (16), the movable contact piece (16b)
Is separated from the fixed contact (16a) and contacts the tip (2a) of the plug (2), and the video signal reproduced by the video tape recorder supplied via the plug (2) is supplied to the video processing circuit (18). Is
The liquid crystal display (19) receives the image reproduced by the video tape recorder.

In the television receiver shown in FIG. 6, simply by attaching or detaching the plug (2) for supplying the video signal, the viewing of the television broadcast and the monitor of the external input video signal are automatically switched.
Operability is good and there are benefits. In particular, in the case of a small-sized receiver using a liquid crystal display as shown in FIG. 6, there is an advantage that the changeover switch and the like can be omitted and the receiver can be made smaller.

[Problems to be solved by the invention]

By the way, since the input impedance of the external video signal input terminal such as the jack (16) is 75Ω, the resistor (17) as the terminating resistor is used as the movable contact (16b) of the jack (16) and the video processing circuit (18). Need to be connected between. However, since this resistor (17) is connected even while the television broadcast signal from the tuner (11) is being supplied to the video processing circuit (18), the detection circuit (12) and the jack (16) are connected. It is necessary to connect a large capacitor (22) with a relatively large capacity of about 1000 μF between the fixed contact piece (16a) and the fixed contact piece (16a), and there is a disadvantage that the television receiver (10) becomes large. It was

In order to solve this problem, for example, by incorporating a terminating resistor in the plug (2) connected to the jack (16), the terminating resistor on the receiver side can be omitted and the capacity of the capacitor (15) can be reduced. Was done, but in this case Jack (16)
As a plug (2) to be connected with, it is necessary to use a dedicated one with a terminating resistor, and there is an inconvenience that the device connectable to the jack (16) is specified and is not versatile.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a video signal input jack device capable of forming a small-sized receiver and selecting a plug to be connected.

[Means for solving problems]

In the video signal input jack device of the television receiver of the present invention, for example, as shown in FIGS. 1 to 4, when the plug is inserted, the input of the video signal is switched from the built-in tuner (11) side to the external device side. Video signal input jack (2
In (0), when the plug (2) is inserted, the central conductor () of the plug (2) provided concentrically with the sleeve (2b) that makes contact with the grounded contact piece (20d) in the jack (20) and conducts 2a) and a single or multiple contact pieces (20a), (20b), (2
0c) and the plug (2) is connected to the contact piece which this single contact piece comes into contact with or is connected to one of a plurality of contact pieces, the built-in tuner (11) and the outside before insertion. Provide a terminating resistor (23) that is not connected to any of the devices, and plug
(2) At the time of insertion, the contact piece (20b) that was in contact with the built-in tuner (11) before the insertion was moved by moving a single contact piece or by moving one of a plurality of contact pieces. It should be separated from the output terminal of 11).

[Action]

According to the video signal input jack device of the television receiver of the present invention, since the terminating resistor (23) is connected only when the plug (2) is connected to the jack (20), the tuner (11)
A small capacitor between the jack and the jack (20).
The size of the jack device and thus the receiver can be reduced, and there is no need to provide a terminating resistor on the plug (2) side, so that the plug (2) that can be connected is not specified and the versatility is high.

〔Example〕

An embodiment of a video signal input jack device of a television receiver according to the present invention will be described below with reference to FIGS. 1 to 4, parts corresponding to those in FIG. 6 are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, (20) shows the entire video signal input jack, and this jack (20) is made of synthetic resin (21)
And a plug insertion hole (21a) is provided at one end of the case (21). Then, as shown in FIGS. 1 and 2, the four contact pieces (20a), (2
0b), (20c) and (20d) are installed substantially parallel to the plug insertion direction (arrow B direction) from the plug insertion hole (21a). The contact piece (20a) has a tip end portion bent inward, and the bent tip end portion is in pressure contact with the tip end portion of the contact piece (20b). The tip of the contact piece (20c) is bent inward, and the contact piece (20c) is arranged at a position substantially facing the contact piece (20a). Further, the contact piece (20d) is located below the contact pieces (20a) and (20c), and the tip portion is more than the other contact pieces (20a) and (20c) in the plug insertion hole.
(21a) It is growing closer. And the contact pieces (20a) and (20b)
Are connected to terminals (24) and (25) respectively, the contact piece (20c) is grounded via a resistor (23) described later, and the contact piece (20d)
Is grounded.

Then, insert the plug (2) through the plug insertion hole (21a),
When this plug (2) is connected to the jack (20), the tip (2a), which is the central conductor at the tip of this plug (2), comes into pressure contact with the contact pieces (20a) and (20c), as shown in FIG. In addition to being in a conducting state, the sleeve (2b) insulated from the chip (2a) by the insulator (2c) is brought into pressure contact with the contact piece (20d) to be in a conducting state. When the plug (2) is connected, the tip (2a) of the plug (2) pushes and bends the contact piece (20a),
(20a) is separated from the contact piece (20b).

Next, the connection state of the jack (20) to the television receiver will be described with reference to FIG. In the television receiver (10) of this example, the video signal output side of the detection circuit (12) is connected to a connector (22) of the jack (20) via a capacitor (22) having a capacity of about 10 μF for removing a direct current component. Connect to terminal (25) connected to 20b). And the terminal (24) connected to the contact piece (20a)
Is connected to the video signal input terminal of the video processing circuit (18).
Further, the contact piece (20c) is grounded via a resistor (23) having a resistance value of 75Ω which constitutes a terminating resistance.

For other configurations of the television receiver of this example,
It is the same as the television receiver shown in FIG.

Next, the operation when receiving an image with the television receiver of this example will be described.First, when performing the image signal reception of the television broadcast signal received by the tuner (11), the jack (20) Do not connect the plug (2). By doing so, the video signal received by the tuner (11) and output by the detection circuit (12) is output to the jack via the capacitor (22).
It is supplied to the contact piece (20b) of (20), and the contact piece (20a) and the contact piece (20b) are in pressure contact with each other when the plug (2) is not connected. Video processing circuit via the contact piece (20a)
The video signal received by the tuner (11) is supplied to (18), and the video signal by television broadcasting is received by the liquid crystal display (19). In this example, no terminal resistance is connected between the detection circuit (12) and the video processing circuit (18) at the time of receiving this television broadcast image.

Next, when receiving a video signal reproduced by a video tape recorder (not shown) as a video signal from the outside,
Insert the plug (2) into which the video signal from this video tape recorder is supplied via the transmission line into the insertion hole (21a) of the jack (20).
Plug it in and connect it to this jack (20). By doing this, the tip (2a) of the plug (2) will contact the contact piece (20a).
This contact piece (20a) separates from the contact piece (20b) when it comes into contact with, and the video signal is no longer supplied to the video processing circuit (18) from the tuner (11) side, and the video obtained by this plug (2) The video signal reproduced by the tape recorder is supplied to the video processing circuit (18). And at this time, the contact piece (20c) to which the resistor (23) is connected comes into contact with the chip (2a),
One end of the resistor (23) is brought into conduction with the contact piece (20a) side via (2a). Therefore, with the resistor (23), which is a terminating resistor, connected to the transmission line from the video tape recorder, the video signal from the video-telecoder side is supplied to the video processing circuit (18), and the reproduced video is reproduced. Signal is liquid crystal display
Received at (19).

As described above, according to the television receiver using the jack (20) of this example as an external video signal input terminal, the image to be received (the tuner) is automatically displayed when the plug (2) is attached to or detached from the jack (20). The video signal from the 11) side and the video signal from the outside can be switched. In this example, when the plug (2) is connected to this jack (20), the resistor (23), which is a terminating resistor, is connected to the input side of the video processing circuit (18). It is possible to match the input impedance to the input signal) to the input impedance of the video processing circuit (18). And this resistor (23)
The video signal from the tuner (11) is the video processing circuit (18)
Is not connected to the video processing circuit (18) side when it is being supplied to the
A small-sized one having a small capacity of about F can be used, and the television receiver can be constructed in a small size. In particular, a compact receiver using a compact display device such as a liquid crystal display as shown in FIG. 1 can be made smaller.

Also, because a terminating resistor is built into this television receiver, it is not necessary to use a special one with a built-in terminating resistor as the plug (2) to connect to the jack (20), and a connectable plug (video Any device).

In the above embodiment, the resistor (23) is the plug (2).
The chip (2a) of the contact piece (20a), that is, the video processing circuit (1
Although it is set to be conductive with the input side of 8), for example, the fifth
As shown in the figure, as a video signal input jack (30), when the plug (2) is inserted, the contact piece (30a) that comes into contact with the plug (2) and is pushed up as shown by arrow A is only attached when the plug is not attached. Use a contact piece (30b) that makes contact and a contact piece (30c) that makes contact only when the plug is attached, and supply the video signal to the contact piece (30a) from the tuner (11) side. (30b)
Is connected to the video signal input side of the video processing circuit (18), and the contact piece (3
0c) may be grounded via a resistor (23).
By doing this, the resistor (23) is not connected when the plug (2) is not installed, and the resistor (23) is only connected when the plug (2) is installed.
(23) is connected, and the same action and effect as those of the above-described embodiment can be obtained.

Further, the present invention is not limited to the above-described embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[Effect of device]

According to the video signal input jack device of the television receiver of the present invention, the capacitor connected between the tuner and the jack can have a small capacity and a small size, and the jack device can be miniaturized. There is no need to provide a terminating resistor on the plug side to be connected with, and there is an advantage that the plug that can be connected is not specified and the versatility is high.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a video signal input jack device of a television receiver of the present invention, FIG. 2 is a perspective view of FIG. 1 example, and FIG. 3 is a connection state of FIG. FIG. 4 is a sectional view showing a television receiver using the jack shown in FIG. 1, FIG. 5 is a sectional view showing another embodiment of the jack device of the present invention, and FIG. It is a block diagram which shows an example of the television receiver of. (2) is a plug, (2a) is a tip, (20) is a jack, (20a),
(20b), (20c) and (20d) are contact pieces, (21) is a case, (2
2) is a capacitor and (23) is a resistor.

Claims (1)

[Scope of utility model registration request] 1. In a video signal input jack device of a television receiver in which a video signal input is switched from a built-in tuner side to an external device side when the plug is inserted, the ground in the jack is inserted when the plug is inserted. A single or a plurality of contact pieces, which are concentrically provided with the sleeve and which are in concentric circles with the contact piece, and which are in a conductive state with the central conductor of the plug, and the single contact piece is in conductive contact when the plug is inserted. A connecting piece or one of the plurality of connecting pieces, which is provided with a terminating resistor which is not connected to the built-in tuner or an external device before the insertion and which is connected to the connecting piece. The contact piece that was in contact with the built-in tuner before the insertion was separated from the output terminal of the built-in tuner by the movement of the single contact piece or the movement of one of the plurality of contact pieces. A jack device for inputting a video signal of a television receiver characterized in that.