JP3098878B2 - Television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver and a monitor capable of displaying a small screen and a multi-screen.

[0002]

2. Description of the Related Art In recent years, television receivers and monitors capable of multi-screen display have been commercialized. Hereinafter, an example of the above-described conventional small-screen superposition circuit will be described with reference to the drawings.

FIG. 4 shows an example of a conventional sub-picture superimposing circuit of a television receiver.

In FIG. 4, reference numeral 41 denotes an external input terminal for inputting a main screen image signal to be displayed as a main screen. An input terminal 42 inputs a small-screen image signal input from the input terminal 41 and a small-screen switching signal indicating a period for displaying the small screen. A constant voltage circuit 43 outputs a specific voltage. Reference numeral 44 denotes a main screen image signal switching circuit.
And a specific voltage output from the constant voltage circuit 43, and by controlling a child screen switching signal input from the input terminal 42, the parent screen image signal is transmitted during a period during which a child screen is displayed. The voltage is switched to a specific voltage value for a corresponding period and output.

[0005] Reference numeral 45 denotes a parent / child image switching circuit, which receives a parent screen image signal input from the parent screen image signal switching circuit 44 and a child screen image signal input from the input terminal 42 and inputs a child screen image signal from the input terminal 42. By switching the parent screen image signal and the child screen image signal under the control of the switching signal, the parent image and the child image are combined and output to the output terminal 46.

FIG. 5 shows another example of a sub-picture superimposing circuit of a conventional television receiver.

In FIG. 5, reference numeral 51 denotes an external input terminal for inputting a main screen image signal to be displayed as a main screen. Reference numeral 52 denotes an input terminal for inputting a small-screen image signal input from the input terminal 51 and a small-screen switching signal indicating a period for displaying the small screen. Reference numeral 53 denotes a low-pass filter which inputs a main screen image signal from the input terminal 51 and outputs the signal in a frequency band where crosstalk is not a problem. Reference numeral 54 denotes a main screen image signal switching circuit, which inputs a main screen image signal from the input terminal 51 and a band-limited main screen image signal output from the low-pass filter 53, and a sub-screen input from the input terminal 52. By controlling the switching signal, the main screen image signal is switched to a band-limited image signal and output during a period corresponding to a period during which the child screen is displayed.

A parent / child image switching circuit 55 receives a parent screen image signal input from the parent screen image signal switching circuit 54 and a child screen image signal input from the input terminal 52, and switches a child screen from the input terminal 52. By switching between the parent screen image signal and the child screen image signal by controlling the signal, the parent screen image and the child image are combined and output to the output terminal 56.

According to the above-described conventional example, all or a part of the image signal of the main screen is converted to a specific voltage value or a specific time constant during a period corresponding to a period during which the sub-screen is displayed. By providing a main screen image signal switching circuit that outputs the signal through a low-pass filter having the same, even when the crosstalk between the parent image and the child image of the parent / child image switching circuit is large, the parent image is converted to the child image. The amount of crosstalk can be reduced.

[0010]

However, in the above configuration, the switching between the parent image and the child image of the parent-child image switching circuit and the switching of the parent image of the parent screen image signal switching circuit with a specific voltage or low-pass voltage are performed. Since the switching of the main screen image signal via the filter is performed at the same timing, if the switching delay time of each switching circuit is different, a difference in the parent image or the child image corresponding to the difference may occur, There remains a problem that ringing generated at the time of switching of the main screen image signal switching circuit is seen in a switching portion.

An object of the present invention is to provide a television receiver which solves the above problems.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a television receiver according to the present invention is configured to output simultaneously a small-screen image signal and the small-screen image signal, and to output the small-screen image signal during the output period. A small-screen creation circuit that outputs a small-screen switching signal that is output for a shorter time than a specific time, a delay circuit that receives the small-screen switching signal and outputs the delayed signal by the same time as the specific time, A sub-screen switching signal and a signal output from the delay circuit are input, a multiplying circuit that outputs a product of the signals, and a sub-screen switching signal and a signal output from the delay circuit are input, and those signals are input. parent screen said multiplier circuit, but for outputting switching a specific voltage at the time of outputting a signal instead of outputting the main picture image signal in the case of an addition circuit which outputs the sum of, display the child screen The image signal switching circuit inputs the output signal of the small-screen image signal and the main picture image signal switching circuit which outputs the child screen creation circuit, an output for switching signal period of said adder circuit to small-screen image signal And a parent / child image switching circuit for combining and outputting the parent / child screen by switching the other periods to the parent screen image signal.

[0013]

According to the present invention, the main screen image signal
The switching of the signal switching circuit is switched by a switching signal that has entered the area of the child screen for a specific time set by the delay circuit at both the rising and falling in the horizontal direction, compared to the switching signal of the parent and child image switching circuit. Therefore, even if the switching delay time of the main screen image signal switching circuit and the switching time of the parent and child image switching circuit are different, if the specific time set in the delay circuit is made larger than the difference between them, the parent image or the child image can be obtained. Is not missing.

[0014] Also, with respect to ringing generated at the time of switching of the main screen image signal switching circuit , if the specific time is set longer than ringing, the ringing becomes a child image area and is not output from the parent / child image switching circuit. In fact, it becomes invisible and the screen becomes unsightly.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) Hereinafter, a small-screen superimposing circuit of a television receiver according to one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of the configuration of a sub-screen superposition circuit, and FIG. 2 shows the operation thereof.

In FIG. 1, reference numeral 11 denotes a small-screen creation circuit which outputs a small-screen image signal (FIG. 2 (a)) simultaneously with the output of the small-screen image signal and a specific period based on the output period of the small-screen image signal. A signal output for a period shorter than the time, that is, as shown in FIG. 2 (b), the horizontal direction starts from a portion corresponding to the time on the left side of the child screen, and a certain time from the child image period. A small screen switching signal which stands in a period shorter by D and stands in a portion corresponding to the image signal of the small screen in time in the vertical direction is output.

Reference numeral 12 denotes a delay circuit, and
1 is input, and is output after being delayed by the specific time D.

Reference numeral 13 denotes a multiplying circuit which receives the small picture switching signal and a switching signal delayed by a specific time D output from the delay circuit 12 and outputs a product of the switching signals.

Reference numeral 14 denotes an adder circuit for inputting the sub-screen switching signal and a switching signal delayed by a specific time D output from the delay circuit 12, and outputting the sum of the switching signals. As shown in FIG. 2, the signal output from the adder circuit 14 temporally corresponds to the child image signal in the horizontal direction, and the signal output from the multiplication circuit 13 has a period corresponding to the child screen image signal in the horizontal direction. Both the left and right sides of the child image are shorter by a specific time D.

Reference numeral 15 denotes a main screen image signal switching circuit, which inputs a main screen image signal to be displayed as a main screen and, when displaying a sub screen, outputs the switching signal output period of the multiplication circuit 13 and the main screen. The image signal of the constant voltage circuit 17
Switch to output voltage and output.

Reference numeral 16 denotes a parent-child image switching circuit, which outputs a child-screen image signal output from the child-screen creation circuit 11 and a parent-screen image signal.
The main screen image signal output from the signal switching circuit 15 is input,
By switching the output period of the switching signal output from the adder circuit 14 to the child image signal and the other periods to the parent screen image signal, the parent and child are combined and output.

With this arrangement, it is possible to eliminate lack of a parent screen or a child screen due to a difference in switching delay time in the parent-child image switching circuit.

(Embodiment 2) FIG. 3 shows another embodiment of the small picture superimposing circuit of the television receiver according to the present invention.

In FIG. 3, reference numeral 31 denotes a small screen image generating circuit, which is output simultaneously with the small screen image signal and the output of the small screen image signal, and is outputted for a specific time shorter than the output period of the small screen image signal. It outputs a child screen switching signal which is a signal.

Reference numeral 32 denotes a delay circuit which receives a small-screen switching signal output from the small-screen creation circuit 31 and outputs the signal after delaying the specific time D.

Reference numeral 33 denotes a multiplication circuit which receives the small picture switching signal and a switching signal delayed by a specific time D output from the delay circuit 32, and outputs a product of these switching signals.

Numeral 34 denotes an adder circuit for inputting the child screen switching signal and a switching signal delayed by a specific time D output from the delay circuit 32, and outputting the sum of the switching signals. As shown in FIG. 2, the signal output from the adder circuit 34 is temporally equivalent to the child image signal in the horizontal direction, and the signal output from the multiplier circuit 33 is a signal corresponding to the period corresponding to the child screen image signal in the horizontal direction. Both the left and right sides of the child image are shorter by a specific time D.

Reference numeral 35 denotes a main screen image signal switching circuit , which inputs a main screen image signal to be displayed as a main screen and a main screen image signal via a low-pass filter, and performs multiplication when the sub screen is displayed. The output period of the switching signal output from the circuit 33 is switched to the parent screen image signal via the low-pass filter, and the other periods are switched and output to the parent screen image signal.

Reference numeral 36 denotes a parent / child image switching circuit, which outputs a child screen image signal output from the child screen creation circuit 31 and a parent screen image signal.
The main screen image signal output from the signal switching circuit 35 is input,
By switching the output period of the switching signal output from the adder circuit 34 to the child image signal and the other periods to the parent screen image signal, the parent and child are synthesized and output.

As a result, similarly to the first embodiment, omission of a parent screen or a child screen due to a difference in switching delay time in the parent-child image switching circuit can be eliminated.

[0032]

As described above, according to the present invention, even when the crosstalk between the main screen image signal and the sub image signal of the parent and child image switching circuit is large, the part of the main screen image in which the sub images are superimposed is DC. Or lowering the frequency band, it is possible to reduce the amount of crosstalk from the parent image to the child image.

Further, the switching of the main screen image signal switching circuit is performed by using the switching signal of the parent and child image switching circuit,
Both rising and falling in the horizontal direction can be switched by the switching signal enters a region of a particular time duration Dakeko screen set by the delay circuit, the main screen image
Even if the switching delay times of the signal switching circuit and the parent-child image switching circuit are different, if the specific time set by the delay circuit is made larger than the difference between them, the parent image or the child image will not be lost.

Also, with respect to ringing that occurs during switching of the main screen image signal switching circuit , if the specific time is set to be longer than the ringing, the ringing becomes a child image area and is not output from the parent / child image switching circuit. This has the effect of actually disappearing.

[Brief description of the drawings]

FIG. 1 is a block diagram of a child screen superimposing circuit of a television receiver according to an embodiment of the present invention.

FIG. 2 is a diagram showing the operation of the block diagram.

FIG. 3 is a block diagram of a sub-picture superimposing circuit of a television receiver according to another embodiment of the present invention.

FIG. 4 is a block diagram of a conventional small-screen superimposing circuit.

FIG. 5 is a block diagram of a conventional sub-picture superimposing circuit.

[Explanation of symbols]

12, 32 delay circuit 13, 33 multiplication circuit 14, 34 addition circuit 15, 35 main screen image signal switching circuit 16, 36 parent and child image switching circuit 17 constant voltage circuit

Claims (2)

(57) [Claims] 1. A sub-screen which outputs a sub-screen image signal and a sub-screen switching signal which is output simultaneously with the output of the sub-screen image signal and output for a specific time shorter than the output period of the sub-screen image signal. A creation circuit, a delay circuit that inputs the child screen switching signal and outputs the signal delayed by the same time as the specific time, and inputs the child screen switching signal and a signal output from the delay circuit, and A multiplication circuit that outputs a product, an addition circuit that inputs the child screen switching signal and the signal output from the delay circuit, and outputs a sum of those signals, and a multiplication circuit that outputs a sum of the signals. parent-screen image signal to output switching certain voltage in instead of outputting the main picture video signal to a period for outputting
A signal switching circuit , a small screen image signal output from the small screen creation circuit and a signal output from the main screen image signal switching circuit are input, and a switching signal period output by the addition circuit is converted to a small screen image signal. A television receiver, comprising: a parent-child image switching circuit for combining and outputting a parent-child screen by switching the other periods to a parent screen image signal. 2. A main screen image signal switching circuit converts a main screen image signal input thereto and a main screen image signal input through a low-pass filter having a specific time constant into a sub screen. 2. The television receiver according to claim 1, wherein the output is switched between display and non-display.