JPH06233210A - On-screen display circuit - Google Patents

Abstract

(57) [Summary] [Purpose] The character and its background are displayed superimposed on the video signal. [Structure] Before and after an RGB processor 14 having an adder circuit 13 for inputting a parent-child screen switching signal and a blanking signal corresponding to a video period of a child screen, adding and outputting those signals, and having a two-stage switching circuit. In the switching circuit, the video signal of the main screen is switched to the video signal of the blank child screen output from the RGB processor 12 by the switching signal output from the adder circuit 13 to switch to the video signal of the sub screen and the main screen. The part corresponding to the character of the video part of is blanked. The blanked signal is further switched to the character by the switching circuit 2 of the RGB processor 14 by the switching signal generated from the character signal itself, so that the switching circuit of the main screen is realized in two stages and all the background colors are included. An on-screen display circuit that can superimpose a color character signal on the video signal of the main screen or child screen.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art An example of the conventional on-screen display circuit described above will be described below with reference to the drawings.

FIG. 5 shows a configuration example of a conventional on-screen display circuit. A character generator 51 outputs a character signal for on-screen display and a blanking signal for blanking the video signal.

Reference numeral 50 denotes a child screen image signal processing circuit which outputs a child screen image signal and a parent-child screen switching signal corresponding to a child screen period.

Reference numeral 53 denotes an RGB processor, which inputs the image signal of the child screen output from the child screen image signal processing circuit 50, processes the image, and then outputs it.

Reference numeral 52 is also an RGB processor A, and a switching circuit for switching the video signal of the parent screen and the video signal of the child screen output from the RGB processor 53 by a parent-child screen switching signal output from the child screen signal processing circuit 50. It has a switching circuit for switching between its output and the character signal output by the character generator 51 according to the character signal output by the character generator 51.

FIG. 6 shows another example of the configuration of a conventional on-screen display circuit. A character generator 61 outputs a character signal for on-screen display and a blanking signal for blanking the video signal.

Reference numeral 60 denotes a child screen image signal processing circuit which outputs a child screen image signal and a parent / child screen switching signal corresponding to the child screen period. Reference numeral 63 denotes an RGB processor, which inputs the image signal of the child screen output from the child screen image signal processing circuit 60, processes the image, and then outputs the image signal.

A bias circuit 64 outputs a predetermined bias voltage. Reference numeral 62 denotes an RGB processor, and a switching circuit for switching the video signal of the parent screen and the video signal of the child screen output from the RGB processor 63 by the parent-child switching signal output from the child screen signal processing circuit 60, and its output and bias circuit. A switching circuit for switching the bias voltage output by 64 by the blanking signal output by the character generator 61, and a switching signal created by the character signal output by the character generator 61 between the output and the character signal output by the character generator 61. It has a switching circuit for switching by.

The above-described configuration and operation have realized an on-screen display circuit that outputs the on-screen display by superimposing it on the video signal of the main screen or the sub-screen.

[0011]

However, in the configuration example shown in FIG. 5, since the switching circuit at the final stage controls the switching timing by the character signal itself, the character signal which is originally one color of the on-screen display is displayed. Is switched to the video signal side for the background color mode in which there is no output and the blanking signal is output,
There is a problem that the color cannot be displayed on screen. Further, in the example shown in FIG. 6, on-screens of all colors can be displayed, but a three-stage switching circuit is required on the main screen, which has a drawback that image quality may be deteriorated.

As described above, the conventional example has a drawback in that the color that can be originally displayed cannot be displayed in the on-screen display, or that a three-stage switching circuit is required in the main screen.

The present invention is intended to provide an on-screen display circuit which solves the above-mentioned drawbacks.

[0014]

In order to solve the above problems, an on-screen signal display circuit of the present invention outputs a character signal for on-screen display and a blanking signal for blanking a video signal. A character generator for outputting and a video signal of the sub-screen, a sub-screen signal processing circuit that outputs a specific voltage during a video period other than the video period of the sub-screen, and a video signal of the sub-screen,
A first switching circuit 3 having means for switching the specific voltage according to a blanking signal output from the character generator, a parent-child screen switching signal and a blanking signal corresponding to a video period of a child screen are input, and these are input. A second addition means for logically adding the signals and outputting the second addition signal; and a means for switching the image signal of the blank child screen and the image signal of the parent screen output by the first switching circuit according to the signal output by the addition circuit Switching circuit, a switching signal generated from the parent-child screen combined image signal output from the second switching circuit, and the blanking signal output from the character generator or the character signal itself to the character signal output from the character generator. The on-screen display circuit is characterized by having a switching circuit having means for switching by.

Alternatively, a bias circuit for outputting a voltage according to the background color of the character is added to the on-screen display circuit under the control of the microcomputer, whereby the sub-screen signal processing circuit, which is a constituent element, is added together with the video signal of the sub-screen. During a video period other than the sub-screen video period, the microcomputer is controlled to develop a sub-screen signal processing circuit that outputs a voltage according to the background color of the character. And an on-screen display circuit having these components by developing a switching circuit having means for switching the voltage output from the bias circuit according to a blanking signal output from the character generator.

[0016]

With the above-described structure, the on-screen display circuit of the present invention is such that the first switching circuit switches the period corresponding to the blanking signal output from the character generator from the sub-picture video signal to a specific voltage. Then, the portion corresponding to the character of the video portion of the child screen is blanked and output.

In the second switching circuit, the video signal of the parent screen is switched to the video signal of the blank child screen output from the first switching circuit by the switching signal output from the adding circuit. While switching to the video signal of the sub screen, the part corresponding to the character of the video part of the main screen is blanked. As a result, if the period corresponding to the blanking signal is other than the period of the child screen, the image signal of the parent screen is blanked by switching to the specific level of the child screen signal. If the period corresponding to the blanking signal is the period of the child screen, it has already been blanked to a specific level by the first switching circuit. By switching the video signal of the blank main screen or the sub screen in this way to the character signal by the switching signal created from the character signal itself in the 39th switching circuit, the main screen switching circuit is realized in two stages. In addition, it is possible to realize the on-screen display of the characters with black borders of all colors on the video signal of the parent screen or the child screen.

Alternatively, a bias circuit for outputting a voltage according to the background color under the control of the microcomputer is added to the on-screen display circuit, whereby a sub-screen signal processing circuit, which is a component, is added to the sub-screen together with the video signal of the sub-screen. During the video period other than the video period of, the microcomputer is controlled to develop into a sub-screen signal processing circuit that outputs a voltage according to the background color of the character, and the first switching circuit is used for the sub-screen video signal and the bias signal. By developing a switching circuit having means for switching the voltage output from the circuit by the blanking signal output from the character generator,
It is possible to realize the main screen switching circuit in two stages, and to realize on-screen display of all color characters and arbitrary background colors on the video signal of the main screen or the sub screen.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An on-screen display circuit according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an on-screen display circuit according to claim 1 of the present invention, and its operation is shown in FIG.

A character generator 11 outputs a character signal for on-screen display. An example of the character signal is shown in FIG. At the same time, a blanking signal for blanking the video signal is output. The blanking signal is shown in FIG.

Reference numeral 10 denotes a child screen signal processing circuit which outputs a child screen image signal and a parent / child screen switching signal corresponding to a child screen period. An example of the video signal of the small screen is shown in FIG. The video signal of the sub-screen has a constant black level of the video signal of the sub-screen during the signal period other than that corresponding to the sub-screen portion.

Reference numeral 12 is an RGB processor, which has an input end 4 for analog input and an input end 5 in another system.
It has a function of clamping the signal input from the input terminal or the signal input from the input terminal 5 and then switching at the timing of the external input control signal. The input terminal 4 of the RGB processor inputs the image signal of the child screen output from the child screen signal processing circuit 11. The input terminal 5 is a bias power source 1 for black level.
Connected to 5. Also, the character generator 1
1 is input as the external input control signal, and the sub-screen video signal input from the input terminal 4 is switched to the input terminal 5 connected to the bias power supply 15 to correspond to the blanking signal. The video signal of the child screen is blanked and output. A video signal of the blanked child screen is shown in FIG.

Reference numeral 13 denotes an adder circuit, which is a sub-picture signal processing circuit 1
The parent-child screen switching signal (shown in FIG. 2 (E)) and the blanking signal output by 1 are input, and the signals are logically added and output. The output signal is shown in FIG.

Reference numeral 14 denotes an RGB processor, which has three systems of an input terminal 1 for digital input, an input terminal 2 for analog input, and an input terminal 3 for inputting a signal input from the input terminal 2 and a signal input from the input terminal 3. After clamping each, switch at the timing of the external input control signal, and switch the signal switched from the signal input from the input terminal 1 to the signal input from the input terminal 1 at the timing of the switching signal. , And has a function of superimposing the signal from the input end 1, the signal from the input end 2 and the signal from the input end 3 and outputting them.

The character signal of the character generator 11 is input to the input terminal 1 of the RGB processor 14. A video signal of the main screen on which the character signal is superimposed is input to the input terminal 2. FIG. 2G shows an example of the video signal of the parent screen. The input terminal 3 inputs the video signal of the blank child screen output from the RGB processor 12. Further, the signal output from the adder circuit 13 is input as the external input control signal, and the video signal of the parent screen input from the input end 2 is switched to the video signal of the blank child screen input from the input end 3. Then, the video signal of the sub-screen is switched to and the period corresponding to the blanking signal is blanked. It is shown in FIG.

At that time, if the period corresponding to the blanking signal is other than the period of the sub-screen, the video signal of the main screen is switched to a constant level of the sub-screen signal to be blanked. If the period corresponding to the blanking signal is the period of the child screen, it has already been blanked by the RGB processor B12. The blanked video signal of the parent screen or the child screen is switched to the character signal input from the input terminal 1 at the timing of the character signal input from the input terminal 1 to switch the character and the background portion to the parent screen or the child screen. The video signal is superimposed and output. Figure 2
The output signal is shown in (I).

As described above, in this embodiment, it is possible to realize the switching circuit for the parent screen in two stages and to superimpose the on-screen display of all colors on the video signal of the parent screen or the child screen.

FIG. 3 shows the configuration of an on-screen display display circuit according to the second aspect of the present invention. Further, FIG. 4 is a diagram showing the operation.

A character generator 31 outputs a character signal for on-screen display. An example of the character signal is shown in FIG. At the same time, a blanking signal for blanking the video signal is output. The blanking signal is shown in FIG.

Reference numeral 30 denotes a sub-picture signal processing circuit which outputs a picture signal of the sub-picture and a parent-child picture switching circuit corresponding to a sub-picture period. An example of the video signal of the small screen is shown in FIG. The video signal of the child screen outputs a voltage according to the background color of the character under the control of the microcomputer during the signal period other than that corresponding to the child screen portion.

A bias circuit 35 outputs a voltage according to the background color of the character under the control of the microcomputer.

Reference numeral 32 is an RGB processor, which has an input end 4 for analog input and an input end 5 in another system.
It has a function of clamping the signal input from the input terminal or the signal input from the input terminal 5 and then switching at the timing of the external input control signal. The image signal of the child screen output from the child screen signal processing circuit 31 is input to the input terminal 4 of the RGB processor 32.

The voltage output from the bias circuit 35 is input to the input terminal 5. Further, the blanking signal output from the character generator 31 is input as the external input control signal, and the image signal of the sub-screen input from the input end 4 is switched to the bias voltage from the input end 5 to obtain the blanking signal. The video signal of the small screen is blanked and output at a voltage corresponding to the background color of the character for a period corresponding to. A video signal of the blanked child screen is shown in FIG.

Reference numeral 33 denotes an adder circuit, which is a sub-picture signal processing circuit 3
The parent-child screen switching signal (shown in FIG. 4 (E)) and the blanking signal output by 1 are input, and the signals are logically added and output. The output signal is shown in FIG.

Reference numeral 34 denotes an RGB processor, which has three systems of input terminals 1 for digital input, input terminal 2 for analog input and input terminal 3 for inputting a signal input from the input terminal 2 and a signal input from the input terminal 3. After clamping each, switch at the timing of the external input control signal, and switch the signal switched from the signal input from the input terminal 1 to the signal input from the input terminal 1 at the timing of the switching signal. , And has a function of superimposing the signal from the input end 1, the signal from the input end 2 and the signal from the input end 3 and outputting them.

The input terminal 1 of the RGB processor 34 inputs the character signal of the character generator 31. The input terminal 2 inputs the video signal of the main screen on which the character signal is superimposed. FIG. 4G shows an example of the video signal of the parent screen.

The input terminal 3 is the RGB processor 32.
Input the blanked sub-picture video signal output by. Further, the signal output from the adder circuit 33 is input as the external input control signal, and the video signal of the parent screen input from the input terminal 2 is switched to the video signal of the blank child screen input from the input terminal 3. Then, the video signal of the sub-screen is switched to and the period corresponding to the blanking signal is blanked. It is shown in FIG. At that time, if the period corresponding to the blanking signal is other than the period of the child screen, the video signal of the parent screen is blanked at a level corresponding to the background color of the character of the child screen signal. If the period corresponding to the blanking signal is the period of the child screen, it has already been blanked by the RGB processor 32. The video signal of the parent screen or the child screen thus blanked is changed to the character signal input from the input terminal 1 at the timing of the character signal input from the input terminal 1 to switch the character signal and the background color to the parent screen or the child screen. Superimpose it on the screen video signal and output. The output signal is shown in FIG.

As described above, in the present embodiment, the switching circuit for the main screen is realized in two stages, and the characters of all colors are superposed on the video signal of the main screen or the sub screen with an arbitrary background color. realizable.

[0040]

As described above, according to the present embodiment, the on-screen display display circuit of the present invention is the first RG.
The first switching circuit of the B processor switches the period corresponding to the blanking signal output from the character generator from the sub-picture image signal to a specific voltage, thereby blanking and outputting the portion of the sub-picture image portion corresponding to the character. To do.

Further, it has an adder circuit for inputting a parent-child screen switching signal corresponding to the video period of the child screen and a blanking signal, theoretically adding these signals and outputting them, and the second switching of the second RGB processor. In the circuit, the video signal of the main screen is switched to the video signal of the blank sub-screen output by the switching circuit by the switching signal output by the adding circuit to switch the video signal of the sub-screen and the video signal of the main screen. Blank the part corresponding to the character.

As a result, if the period corresponding to the blanking signal is other than the period of the child screen, the image signal of the parent screen is switched to the specific level of the child screen signal to be blank. If the period corresponding to the blanking signal is the period of the child screen, it has already been blanked to a specific level by the first switching circuit. By switching the video signal of the blank or parent screen thus blanked to the character by the switching signal created from the character signal itself in the third switching circuit of the second RGB processor, the switching circuit of the parent screen Can be realized in two stages, and the character signals of all colors can be superimposed on the video signals of the parent screen or the child screen.

Alternatively, a bias circuit for outputting a voltage according to the background color is added to the on-screen display circuit under the control of the microcomputer, whereby a sub-picture signal processing circuit, which is a component, is added together with the picture signal of the sub-picture together with the sub-picture. During video periods other than the video period, the sub-screen signal processing circuit that outputs a voltage according to the background color of the character under the control of the microcomputer,
With further development, by developing the first switching circuit into a switching circuit 3 having means for switching the image signal of the sub-screen and the voltage output from the bias circuit according to the blanking signal output from the character generator, It is possible to realize the main screen switching circuit in two stages and to superimpose the character signals of all colors and an arbitrary background color on the video signal of the main screen or the child screen.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an on-screen display circuit according to an embodiment of claim 1 of the present invention.

FIG. 2 is a diagram showing the operation of the on-screen display circuit in the embodiment of claim 1 of the present invention.

FIG. 3 is a configuration diagram of an on-screen display circuit according to a second embodiment of the present invention.

FIG. 4 is a diagram showing the operation of the on-screen display circuit in the embodiment of claim 2 of the present invention.

FIG. 5 is a configuration diagram of an on-screen display circuit according to a first conventional example.

FIG. 6 is a configuration diagram of an on-screen display circuit according to a second conventional example.

[Explanation of symbols]

 11, 31 Character generator 12, 14, 32, 34 RGB processor 13, 33 Adder circuit 35 Bias circuit

Claims (2)

[Claims] 1. A character generator that creates a character for on-screen display and outputs a character signal, and outputs a blanking signal for blanking the video signal, and a video signal of the sub-screen together with a video signal of the sub-screen. During a video period other than the period, a first screen switching means having a sub-screen signal processing circuit for outputting a specific voltage, a sub-screen video signal, and a means for switching the specific voltage by a blanking signal output by the character generator. A circuit, an adder circuit for inputting a parent-child screen switching signal and a blanking signal corresponding to the video period of the child screen, and logically adding those signals, and a blanked child screen image output by the first switching circuit. A signal and a second switching circuit having means for switching the image signal of the main screen according to the signal output from the adding circuit, A means for switching a parent-child screen composite image signal output from the second switching circuit and a character output from the character generator by a blanking signal output from the character generator or a switching signal generated from the character signal itself. An on-screen display circuit having three switching circuits 2. 2. A character generator that outputs a character signal and also outputs a blanking signal for blanking the video signal, a video signal of the sub-screen, and a microcomputer control during a video period other than the video period of the sub-screen. The sub-screen signal processing circuit that outputs a voltage according to the background color of the character, the bias circuit that outputs the voltage according to the background color of the character under the control of the microcomputer, the video signal of the sub-screen, and the output of the bias circuit The first switching circuit having a means for switching the voltage to be generated by the blanking signal output from the character generator, the parent-child screen switching signal and blanking signal corresponding to the video period of the child screen are input, and these signals are logically input. An adder circuit for adding and outputting, and a blanked sub-screen video signal output by the first switching circuit A second ninth switching circuit having means for switching the image signal of the parent screen according to the signal output from the adding circuit, an image signal of the parent-child screen composite output from the second ninth switching circuit, and an output of the character generator An on-screen display circuit having a third switching circuit having means for switching a character signal to be generated by a blanking signal output from a character generator or a switching signal generated from the character signal itself.