JPH0531996B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a device for controlling on-screen display that displays characters, etc. on the screen of a television receiver.

(b) Conventional technology In recent years, video equipment such as television receivers (hereinafter referred to as ``TV receivers'') and video tape recorders (hereinafter referred to as ``VTR'')
An on-screen display circuit is added to display characters, etc. on the cathode ray tube screen of the television receiver.
Various functions of a VTR are now displayed on a cathode ray tube screen.

In other words, for a single TV receiver equipped with an on-screen function, for example, as shown in Figure 4a,
Reception channel "CH13" appears on the screen of TV receiver 1
As shown in figure b, the mode display "AV1" indicates that the mode is set to accept input from a VTR.
or the times shown in a and b in the same figure ("12:34", "12:
25”) and volume level on-screen.
Furthermore, when a VTR 2 equipped with an on-screen display function is connected to the TV receiver 1 as shown in FIG.
It is displayed on the screen of the receiver 1. Figure 5a is
When the VTR 2 enters the playback mode, the display "PLAY" indicating the playback mode and the tape count value "0123" are displayed for several seconds, and Figure b shows the calendar display. , Figure c shows a state where a reservation for timer recording is displayed.

By the way, when playing back a tape that has already been recorded on a VTR, the method of outputting the video and audio signals from the VTR to the TV receiver involves converting the recorded content of the recorded tape into an RF signal and then outputting it to the TV receiver's antenna. How to input to the terminal and the recorded contents of the recorded tape as baseband video/audio signals to the TV
There is a method of inputting to the video input terminal and audio input terminal of the receiver.

Figure 3 shows a TV receiver 1 connected to reproduce video and audio signals using the latter method.
A schematic block diagram of the VTR2 is shown.

In the TV receiver 1, 3 is a reception detection circuit including from a tuner to a video detection circuit, 4 is a channel selection circuit including a microcomputer, etc., and 5 is a reception detection circuit including a tuner to a video detection circuit.
1 is an audio signal reproducing circuit, 6 is a speaker, 7 is a video amplifying circuit, 8 is a color signal reproducing circuit for reproducing the color signal extracted from the video amplifying circuit 7, 9 is a synchronization/deflection circuit, 10 is a video output circuit, 11 is a cathode ray tube, 13 is a first on-screen display circuit, 14
is a mode changeover switch circuit for switching between the TV reception mode and the VTR reception mode, and the switch circuit 14 is set to the input end T side in the TV reception mode, and is set to the input end V side in the VTR reception mode. 15 is an audio signal input terminal, 16 is a video signal input terminal, and 17 is a mode switching signal input terminal.

On the other hand, in the VTR 2, 18 is a control circuit composed of a microcomputer, etc. having channel selection and other functions, 19 is a second on-screen display circuit, 20 is a synchronization circuit, 21 is an addition circuit, 22
23 is an audio signal output terminal, 23 is a video signal output terminal,
24 is a mode switching signal output terminal,
Most of the internal configuration is omitted.

The mode changeover switch 14 can be driven by a signal from the channel selection circuit 4 of the TV receiver 1, and can also be driven automatically by a mode changeover signal supplied from the control circuit 18 when the VTR 2 is in the playback state. The mode is switched to VTR reception mode (input terminal V side). The technique of automatically setting the VTR reception mode when the VTR 2 enters the playback state is also described in, for example, Japanese Utility Model Publication No. 60-5667.

Then, for the on-screen display from the VTR 2, the display signal output from the display circuit 19 driven by the synchronization signal is superimposed on the baseband video signal by the adder 21 and sent from the output terminal 23 to the input terminal 16 of the TV receiver 1. This is done by supplying At this time, the control circuit 18 specifies a display pattern to the display circuit 19 and switches the mode changeover switch 14 to the input terminal V side.

However, in this way, the mode changeover switch 1
4 switches to VTR reception mode, the on-screen display function of the TV receiver 1 itself is activated, and the display circuit 13 is activated based on the command signal from the channel selection circuit 4.
is driven by a synchronizing signal and produces an on-screen display as shown in FIG. 4b.

On the other hand, the VTR2 outputs an on-screen display as shown in Figure 5a, and as a result, the TV receiver screen displays Figures 4b and 5a as shown in Figure 6.
An overlapping display such as this will be displayed.
As a result, viewers may lose track of what is being displayed, or watch it on their TV receiver or watch it.
This has the inconvenience of making you think that the VCR has malfunctioned. However, such inconvenience
This problem also occurs when the mode selector switch does not change automatically when the VTR's on-screen display is activated, that is, when the TV receiver is manually set to VTR reception mode and then the VTR output is input.

However, there is a circuit shown in FIG. 1 to overcome the drawbacks of the conventional example.

In FIG. 1, focusing on the fact that the first and second on-screen display circuits 13 and 19 do not operate unless horizontal and vertical synchronizing signals are supplied, an AND gate circuit 25 is provided on the TV receiver side. The horizontal and vertical synchronizing signals from the synchronous deflection circuit 9 are input to one input terminal of the gate circuit 25, and the mode switching signal from the VTR 2 is input to the other input terminal.
The output is input to the first on-screen display circuit 13. Therefore, when the second on-screen display circuit 19 operates in the VTR reception mode, the mode switching signal output from the control circuit 18 is set so that the switch circuit 14 is switched to the input terminal V side by a low signal. If this low signal is applied to the other input terminal of the AND gate circuit 25, the horizontal and vertical synchronizing signals are not input to the first on-screen display circuit 13, and the first
The on-screen display circuit 13 is inactive, and no overlapping of displays as shown in FIG. 6 occurs.

Conversely, in the TV reception mode, the mode switching signal output from the control circuit 18 is set as a high signal.
If this high signal is set so that the switch circuit 14 is switched to the input terminal T side, this high signal is applied to the other input terminal of the AND gate circuit 25, so that the first on-screen display circuit 13 The horizontal and vertical synchronizing signals are input, the first on-screen display circuit 13 is activated, and as a result, on-screen display can be performed on the screen of the TV receiver 1.

As the first on-screen display circuit, a commercially available IC NEC Corporation model number μPD6105C can be used, and as the second on-screen display circuit, a commercially available IC NEC Corporation model number μPD6105C can be used. Model number
MN12871CA can be used.

However, when a plurality of external devices are connected, it is not possible to switch the on-screen display functions of the plurality of external devices because the on-screen display circuit of the TV receiver is controlled by a single control.

In addition, an on-screen display circuit is always required as an external device, and external devices that do not use this circuit must be provided with a separate circuit, which increases the number of parts and increases costs.

Furthermore, a circuit for detecting a synchronization signal is also required as an external device, and a synchronization signal must be input from another circuit to an external device that does not use a synchronization signal, making the circuit complicated.

(C) Problems to be Solved by the Invention The present invention solves the above-mentioned drawbacks of the conventional example, that is, prevents the on-screen display from the TV receiver from overlapping with the on-screen display from an external device such as a VCR. It is.

Moreover, in the present invention, when a plurality of external devices are connected, which is a disadvantage of the conventional example, all of them are converted into a single control signal, so that the on-screen display circuit can be controlled without any problem. Furthermore, even in external equipment that does not have an on-screen display circuit, the operating state can be displayed on-screen.

Furthermore, since the synchronization signal uses the signal from the TV receiver, there is no need for any particular circuit to detect the synchronization signal.

(d) Measures to solve the problem When the on-screen display circuit installed inside an external device such as a VTR connected to a TV receiver is activated.
A means is provided for disabling the on-screen display circuitry within the TV receiver.

Furthermore, means is provided for controlling the on-screen display circuit of the external device using the synchronization signal of the TV receiver.

It also includes means for detecting the operating state of external equipment and displaying it on-screen.

(E) Effect With the above configuration, the on-screen display from the TV receiver side and the on-screen display from the external device such as a VTR will not overlap.

Furthermore, even if the external device does not have an on-screen display circuit built-in, its operating status can be displayed on-screen.

(F) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIG. 2, but the same parts as in FIG. 1 or 3 are given the same reference numerals, and the explanation thereof will be omitted.

FIG. 2 shows an embodiment of the present invention. In this embodiment, in order to display on-screen the functions of a system audio device 27 such as a compact disc player on the TV receiver 1,
and audio equipment 27 and external display signal generator 2
It is connected via 6. In this example,
The TV receiver 1 is provided with a synchronization signal output terminal 27, a control signal input terminal 28, and a display signal input terminal 29, and the horizontal and vertical synchronization signals from the synchronization deflection circuit 9 are input to one input terminal of the AND gate circuit 25. and is also applied to the synchronizing signal output terminal 27, and a signal from the control signal input terminal 28 is applied to the other input terminal. Further, the display signal of the first on-screen display circuit 13 is used as one input,
An OR gate circuit 30 is provided which takes the display signal from the display signal input terminal 29 as the other input and supplies its output to the cathode of the cathode ray tube.

The display signal generator 26 includes a control circuit 31 made of a microcomputer, and the second on-screen display circuit 32.
The control signal is supplied to a control signal output terminal 33 connected to the control signal input terminal 28, and the mode switching signal is supplied to a mode switching signal output terminal 34 connected to the mode switching signal input terminal 17. The display circuit 32 has a synchronization signal output terminal 27
TV via the synchronization signal input terminal 35 connected to
It operates when horizontal and vertical synchronizing signals are supplied from the receiver 1 side, and the output display signal is sent to the display signal output terminal 3 connected to the display signal input terminal 29.
Supply to 6.

Therefore, when displaying the functions of the audio equipment on-screen, a low-level signal is output as a control signal from the control circuit 31 to one input terminal of the AND gate circuit 25. is inactive because horizontal and vertical synchronizing signals are not supplied thereto, and a display signal from the second on-screen display circuit 32 is supplied to the cathode ray tube 11 through the OR gate circuit 30. At this time, the mode changeover switch circuit 14 is switched to the TV reception mode or the VTR reception mode by the mode changeover signal from the control circuit 31, but the switch circuit 37 cuts off the audio signal to the audio reproduction circuit 5 and sends the TV to the TV reception mode. The audio is reproduced by the audio equipment through a path not shown, or the audio signal of the audio equipment itself is reproduced. At the same time, the on-screen display function on the VTR 2 side is also disabled by a control signal from the control circuit 31. Note that when the on-screen display is not performed by the display signal generator 26, the control circuit 31
The second on-screen display circuit 32 is deactivated by the signal from the AND gate circuit 25.
A high signal is supplied as a control signal, so
On-screen display on the TV receiver 1 side can be performed without any inconvenience.

(g) Effects of the invention As described above, according to the video display device of the present invention,
The on-screen display of a TV receiver and the on-screen display of an external device connected to the TV receiver are not displayed in an overlapping manner, thereby preventing misunderstanding or discomfort from being caused to the viewer.

Furthermore, even when multiple external devices such as VTRs and audio equipment are connected, the on-screen display of the devices used can be performed without the viewer having to perform any complicated operations.

Furthermore, even if the system audio is not equipped with an on-screen display circuit, the control circuit can
The operating status of this system audio can be displayed on-screen.

[Brief explanation of the drawing]

FIG. 2 is a block diagram showing an embodiment of the video display device of the present invention, FIG. 3 is a block diagram showing a conventional video display device, FIG. 1 is a block diagram showing another conventional example, and FIG. 4 is a block diagram showing an example of a conventional video display device. FIG. 5 is a diagram showing an example of on-screen display by a television receiver, FIG. 5 is a diagram showing an example of on-screen display by a video tape recorder, and FIG. 6 is a diagram for explaining the drawbacks of the conventional technology. DESCRIPTION OF SYMBOLS 1... Television receiver, 2... Video tape recorder (external device), 13... First on-screen display circuit, 19... Second on-screen display circuit, 25... AND gate circuit.

Claims (1)

[Scope of Claims] 1. In a video display device that is connected to a television receiver internally equipped with a first on-screen display circuit that displays characters, etc. on the screen, and an external device that serves as a video or audio signal source. , inputting the synchronization signal of the television receiver;
a second on-screen display circuit that supplies a signal for displaying characters, etc. to the television receiver; and a second on-screen display circuit that inputs a signal indicating the operating state of the external device;
In response to the signal, the first on-screen display circuit is made inactive, characters or the like representing the operating state of the external device are outputted to the second on-screen display circuit, and the external device is activated. A video display device comprising a control circuit configured to switch the operation mode of the television receiver according to the state.