JP2003153108A - Television, device and method for muting picture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a television, a device and a method for muting a picture for appropriately muting a picture in a simple way suitable for mass-production. SOLUTION: When muting a picture, a microcomputer 40 outputs a cutoff control signal for lowering an output level than an ordinary value to a chroma IC20. Hence in the chroma IC20, an RGB signal output circuit 25 lowers the output level of RGB signals than the ordinary value. Therefore, even when there is a dispersion in the output levels of respective color components, the coloring of black display on a CRT30 can be reduced. Further, since such operational control can be provided without changing the configuration of hardware, it is suitable for mass-production.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television, a screen mute device and a screen mute method.

[0002]

2. Description of the Related Art A conventional television is provided with a chroma IC connected between a cathode of a CRT and a tuner and a microcomputer connected to the chroma IC as a structure for executing screen mute. . The microcomputer has an OS for blanking the received video when the screen is muted.
An OSD circuit for generating the D signal is provided, and the chroma IC is provided with a superimposing circuit for superimposing the OSD signal on the video signal based on the broadcast signal received by the tuner. Further, in the chroma IC, an RGB output circuit is interposed between the superimposing circuit and the cathode of the CRT, and this RGB output circuit, when the screen is muted,
An RGB signal is output to the cathode based on the video signal on which the OSD signal is superimposed, and a black display is output to the CRT.

[0003]

In the above-described conventional television, the black display output to the CRT may not be completely black, but may be slightly colored. This is because there are variations in the DC level of the RGB signals output from the RGB output circuit, and this variation was reduced by selecting the IC. However, this method has a problem in that the manufacturing process must be provided with a process for selecting usable ICs, and the yield is not good.

A television provided with a screen mute device disclosed in Japanese Patent Laid-Open No. 5-268536 is known in the past. In this television, the signal processing I
A switching circuit is interposed between C and the cathode amplifier, and during the transient operation, the switching circuit is used to mute the screen. Therefore, a new circuit must be added to the existing circuit configuration, and there is a problem that the screen mute function cannot be easily added due to changes in the circuit design and the like. Similarly, as a screen mute device that requires a hardware configuration change, Japanese Patent Laid-Open No. 7-2126
The one disclosed in Japanese Patent No. 17 is also known. The present invention has been made in view of the above problems, and an object of the present invention is to provide a television, a screen mute device, and a screen mute method capable of performing appropriate screen mute by a simple method and suitable for mass production. .

[0005]

In order to achieve the above object, the invention according to claim 1 is an RGB signal output means which is connected to a CRT and outputs an RGB signal to the CRT based on a predetermined signal input, A video which is connected to the chroma IC and has a chroma IC having an OSD signal superimposing means for superimposing an OSD signal on a predetermined video signal and outputting the superimposed OSD signal to the RGB signal output means, and which is output to the CRT based on the RGB signal And a screen mute device including a microcomputer having an OSD signal generating means for generating an OSD signal for blanking the screen to mute the screen. The fast blanking signal is sent to the above OSD
When outputting to the signal superimposing means to superimpose the OSD signal generated by the OSD signal generating means on the video signal,
The RGB signal output means is provided with output level control means for outputting a cutoff control signal for lowering the cutoff level of the RGB output below a normal value, and the RGB signal output means receives the cutoff control signal. When
RG output from the RGB signal output means to the CRT
The DC level of the B signal is lowered below the normal value to reduce the white balance variation on the mute screen.

That is, in the television,
Normally, the RGB signal output means provided in the chroma IC outputs the RGB signal to the CRT based on a predetermined video signal. Therefore, a video corresponding to the same video signal is output on the screen of the CRT. On the other hand, when the screen is muted, the OSD provided in the microcomputer connected to the chroma IC is
The signal generating means generates an OSD signal for blanking the output image on the CRT. Further, the microcomputer outputs a fast blanking signal to the effect that the screen mute is executed to the OSD signal superposing means provided in the chroma IC. Then, the OSD signal superimposing means is
Since the generated OSD signal is superimposed on the video signal and supplied to the RGB signal output means, the RGB signal output means outputs an RGB signal based on the video signal on which the OSD signal is superimposed to the CRT. , Causes the CRT to output a black display as a mute screen.

At this time, the output level control means provided in the microcomputer outputs to the RGB signal output means a cutoff control signal for lowering the cutoff level of the RGB output below the normal value. Then, the RGB signal output means lowers the DC level of the RGB signal output to the CRT to a value lower than the normal value to reduce the variation in white balance on the mute screen. Therefore, the above RGB
Even if the output level of the signal varies for each color component, the coloring of the black display output to the CRT can be reduced. In addition, the screen mute control described above is based on the chroma I
Since it is executed by C and the microcomputer and it is not necessary to change the hardware configuration in order to reduce the variation in white balance on the mute screen, it is also useful in that it can be easily realized.

In the first aspect, the screen mute device having a specific structure provided in the television has been described. However, from the viewpoint that it is enough to easily reduce the white balance variation in the mute screen, In a broader sense, it is possible to capture the screen mute device according to the present invention. As an example thereof, the invention according to claim 2 is an RGB signal output unit that is connected to a video output device and outputs an RGB signal to the video output device based on a predetermined signal input; and an OSD signal superimposed on the predetermined video signal. OSD for outputting to the same RGB signal output means
A chroma IC having signal superimposing means, and the chroma IC
And a microcomputer having an OSD signal generating means for blanking an image output to the screen of the image output device based on the RGB signals to generate an OSD signal for executing the screen mute. In the device, when the OSD signal superposing means superimposes the OSD signal generated by the OSD signal generating means on the video signal and outputs the OSD signal to the RGB signal outputting means, the microcomputer outputs the RGB signal outputting means from the RGB signal outputting means. An output level control means for lowering the output level of the RGB signal output to the video output device to a normal value is provided.

That is, in normal times, the RGB signal output means provided in the chroma IC outputs the RGB signal to the video output device based on the predetermined video signal. Therefore, the video corresponding to the same video signal is output to the screen of the same video output device. On the other hand, when the screen is muted, the above chroma IC
The OSD signal generating means provided in the microcomputer connected to the CPU generates an OSD signal for blanking the output image from the image output device. Then, the above chroma I
The OSD signal superposing means provided in C superimposes the OSD signal generated by the OSD signal generating means on the video signal and supplies the superposed signal to the RGB signal output means. Therefore, the RGB signal output means outputs an RGB signal based on the video signal on which the OSD signal is superimposed to the video output device, and causes the video output device to output black display as a mute screen.

At this time, the output level control means provided in the microcomputer lowers the DC level of the RGB signal output from the RGB signal output means to the video output device to a level lower than the normal value, and adjusts the white balance on the mute screen. Reduce variations. Therefore, even if the output levels of the RGB signals vary for each color component, it is possible to reduce the coloring of black display output to the video output device. Since it is not necessary to change the hardware configuration to execute the above-described screen mute control, it is also useful in that it can be easily realized. It should be noted that from the viewpoint that the video output device can perform video output based on the RGB signals output from the RGB signal output means, in the case of performing video output such as CRT, liquid crystal display and plasma display. The method is not limited.

As an example of the method for lowering the output level of the RGB signals as described above, the invention according to claim 3 is the screen mute device according to claim 2, wherein the output level control means is the above-mentioned. A cutoff control signal for lowering the cutoff level of the RGB output from a normal value is output to the RGB signal output means, and the RGB signal output means outputs the RGB signal when the cutoff control signal is input. It is designed to lower the level. That is, when the screen mute is executed, the output level control means outputs to the RGB signal output means a cutoff control signal for lowering the cutoff level of the RGB output from the normal value. Then, the RGB signal output means lowers the output level of the RGB signal. The cut-off level here is the output level of the RGB signal used when adjusting the white balance in the video output device, so that the present invention can be easily realized by using the existing image quality adjusting function. It becomes possible.

Further, as another example of a method for lowering the output level of the RGB signals, the invention according to claim 4 is the screen mute device according to claim 2 or 3, The output level control means is
A brightness level control signal for lowering the brightness level of the RGB output from a normal value is output to the RGB signal output means,
The RGB signal output means is configured to reduce the output level of the RGB signal when the same brightness level control signal is input. That is, when screen mute is executed,
The output level control means outputs to the RGB signal output means a brightness level control signal for lowering the brightness level of the RGB output from the normal value. Then, the RGB signal output means lowers the output level of the RGB signal. Therefore, like the third aspect, the present invention can be easily realized by utilizing the existing image quality adjusting function. Further, the brightness level collectively increases or decreases the output level of each color component at the time of image quality adjustment. Therefore, the control load on the chroma IC can be reduced by using the brightness level adjusting function. It is also useful in terms.

As an example of a specific method for performing the screen mute, the invention according to claim 5 is the screen mute device according to any one of claims 2 to 4, wherein the microcomputer is A fast blanking signal for executing screen mute is output to the OSD signal superimposing means, and the OSD signal superimposing means generates the OSD signal generated by the OSD signal generating means when the fast blanking signal is input. The signal is superimposed on the video signal. That is, when executing the screen mute, the microcomputer outputs a fast blanking signal to the effect that the screen mute is executed to the OSD signal superimposing means. Then, the OSD signal superimposing means uses the O
The OSD signal generated by the SD signal generating means is superimposed on the video signal. Therefore, while the fast blanking signal is input to the OSD signal superimposing means, the screen mute described above is continued. The claim 5 is useful in that the execution period of the screen mute can be set only by controlling such signal transmission.

By the way, the control method at the time of screen muting as described above can be realized not only as a substantial device configuration but also as a method. As an example, claim 6
The invention according to claim 1 outputs a video signal corresponding to the same video signal to the screen of the video output device by outputting an RGB signal based on a predetermined video signal to the video output device by the chroma IC during normal operation, and the screen mute is performed. At this time, an OSD signal for blanking the same output image is generated by the microcomputer connected to the same chroma IC, the same OSD signal is superimposed on the same video signal by the same chroma IC, and this OSD signal is superimposed. In a screen mute method for outputting an RGB signal based on a video signal to the same video output device, the microcomputer is configured to lower the output level of the RGB signal output to the video output device below a normal value when the screen is muted. is there. That is, the configuration as the above device can also be realized as a method. It goes without saying that the configurations according to claims 3 to 5 can be similarly applied as a method.

[0015]

As described above, according to the present invention, it is possible to perform a proper screen mute by a simple method and provide a television suitable for mass production. Further, according to the invention of claim 2, it is possible to provide an appropriate screen mute by a simple method, and it is possible to provide a screen mute device suitable for mass production. further,
According to the inventions of claims 3 to 5, it is possible to reduce coloring of black display by a simple method. further,
According to the invention of claim 6, it is possible to provide an appropriate screen mute by a simple method, and to provide a screen mute method suitable for mass production.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Here, embodiments of the present invention will be described in the following order. (1) Description of configuration of television device: (2) Description of signal processing in chroma IC: (3) Description of screen mute: (4) Summary:

(1) Description of Configuration of Television Apparatus: FIG.
FIG. 1 is a block diagram showing a schematic configuration of a television according to an embodiment of the present invention. In the present embodiment, the description of the audio signal is omitted, with emphasis on the description of the video signal. In the figure, a tuner 10 receives a television signal of a desired frequency corresponding to a television broadcasting band via an antenna 11, selects only a required signal from the received television signals, amplifies the high frequency, and outputs an intermediate signal. Converted to a frequency signal and output.

When the intermediate frequency signal output from the tuner 10 is input to the chroma IC 20, the chroma IC 20
By performing various kinds of signal processing on the input intermediate frequency signal, the composite video signal is restored and the video signal or the like is extracted. Then, the extracted video signal is supplied to the CRT 30 via the cathode amplifier 31. Where tuner 1
A microcomputer 40 is connected to the 0 and the chroma IC 20, and the microcomputer 40 gives a control instruction to each device and controls the entire apparatus.

(2) Description of signal processing in the chroma IC: In the chroma IC 20, as shown in FIG. 2, the synthesized video signal restored based on the intermediate frequency signal is the video amplification circuit 2
When input to 1, the video amplifier circuit 21 extracts a video signal and a sync signal from the input composite video signal. Then, the extracted video signal is transmitted to the OSD signal superposition circuit 2
2, the sync signal is separated into a horizontal component and a vertical component, and the horizontal deflection circuit 23 and the vertical deflection circuit 24 are respectively separated.
And supplied to.

An RGB signal output circuit 25 is connected to the OSD signal superposition circuit 22, and the RGB signal output circuit 2 is connected.
Reference numeral 5 restores the RGB color components based on the video signal output from the OSD signal superposition circuit 22 and outputs the restored RGB color components to the cathode amplifier 31. Therefore, in the CRT 30, when the RGB signal amplified by the cathode amplifier 31 is supplied to the cathode side, the electron gun irradiates the electron beam corresponding to each color component based on the RGB signal. On the other hand, the horizontal deflection circuit 2
The anode side of the CRT 30 is connected to the 3 and the vertical deflection circuit 24, and the electron beam is deflected in the horizontal / vertical direction based on each synchronization signal. Therefore, CRT3
On the screen of 0, the received video is output based on the composite video signal.

(3) Explanation of screen mute: Here, OS
In addition to the video signal based on the above-described composite video signal, the D signal superimposing circuit 22 can also input the black display OSD fast blanking signal generated by the OSD signal generating circuit 41 included in the microcomputer 40. ing. OSD
When the first blanking signal (FB signal) is input from the microcomputer 40, the signal superimposing circuit 22 superimposes the OSD fast blanking signal on the video signal based on the composite video signal and supplies it to the RGB signal output circuit 25. Therefore, a black display is output on the screen of the CRT 30 instead of the received image, and the screen becomes a mute screen.

For example, when the tuner 10 selects a desired broadcast station, the tuner 10 does not receive a television signal until the reception frequency matches the frequency corresponding to this broadcast station. Distorted images will be displayed. Therefore, during the tuning operation, the microcomputer 40 outputs the FB signal to the chroma IC 20 to cause the OSD signal superimposing circuit 22 to superimpose the OSD fast blanking signal and execute the screen mute. In executing the screen mute as described above, the RG based on the OSD fast blanking signal
The output level of the B signal varies for each color component, and black display may be reddish, bluish, or greenish. Therefore, in the present embodiment, R output from the RGB signal output circuit 25 when the screen is muted
The output level of the GB signal is lowered below the normal value to reduce coloring of black display due to variations in the output level. FIG. 3 is a flowchart showing an example of an operation procedure when the screen is muted.

As shown in the figure, the microcomputer 40 outputs an OSD fast blanking signal corresponding to black display to the OSD signal superimposing circuit 22 when the tuner 10 is given a tuning operation instruction, and at the same time, it outputs a chroma signal. The FB signal and the cutoff control signal for lowering the output level of the RGB signal below the normal value are output to the IC 20 (steps S100 and S110). Then, the chroma IC
20, the OSD signal superposition circuit 22 based on the FB signal
Superimposes the OSD fast blanking signal on the video signal, the video signal on which the OSD fast blanking signal is superposed is input to the RGB signal output circuit 25. Here, as shown in FIG. 4, the RGB signal output circuit 25 outputs the RGB signal to the cathode amplifier 31 based on the input video signal while lowering the DC level below the normal value (steps S120 to S140). .

Therefore, when the RGB signals amplified by the cathode amplifier 31 are supplied to the CRT 30, even if the output level of each color component varies, the deviation of the white balance on the screen of the CRT 30 is reduced. The cutoff control signal referred to here is sent from the microcomputer 40 when the white balance is adjusted in the menu mode or the like.
This is a control signal output to C20. Normally, when a key operation is performed in the menu mode, the microcomputer 40 outputs a cutoff control signal to the chroma IC 20,
The RGB signal output circuit 25 of 20 adjusts the output level for each of the RGB color components. Therefore, in the screen mute operation, coloring of black display is reduced by using the existing control signal.

When the microcomputer 40 detects that the tuner 10 has received the television signal of the desired frequency and has completed the tuning operation, it outputs the OSD fast blanking signal, the FB signal and the cutoff control signal. finish. Therefore, in the chroma IC 20, the OSD signal superimposing circuit 22 finishes superimposing the OSD first blanking signal and only the video signal based on the composite video signal is RG.
B signal output circuit 25 outputs the RGB signal output circuit 25
Outputs an RGB signal based on the same video signal. Therefore,
On the screen of the CRT 30, the disordered video during the channel selection operation is not output, and only the received video is output.

Further, by using another method as shown in FIG. 5, the RGB signal output circuit 25 at the time of screen muting.
It is also possible to lower the output level of the RGB signal output from the. That is, the microcomputer 40 is the tuner 10
When a channel selection operation instruction is given to, the OSD signal superimposing circuit 22 outputs an OSD first blanking signal corresponding to black display, and the chroma IC 20 receives F
The B signal and the brightness level control signal for lowering the brightness level below the normal value are output (steps S200, S).
210).

Then, as in the case of FIG. 3 described above, R
Since the DC level of the GB signal is lowered below the normal value,
When the screen is muted, the deviation of the white balance on the screen of the CRT 30 is reduced (steps S220 to S2).
40). Note that the brightness level control signal referred to here is used by the microcomputer 4 when adjusting the brightness level in the menu mode or the like.
It is a control signal output from 0 to the chroma IC 20. Normally, when a key operation is performed in the menu mode, the microcomputer 40 outputs a luminance level control signal to the chroma IC 20, and the RGB signal output circuit 25 of the chroma IC 20 outputs RGB signals.
Adjust the signal output level all at once. Therefore, when adjusting the brightness level to lower the output level of the RGB signals,
Since it is not necessary to adjust the output level for each color component,
This is useful in that the control efficiency in the chroma IC 20 can be improved and the load during operation can be reduced.

(4) Summary: As described above, since the microcomputer 40 outputs the cutoff control signal to the chroma IC 20 to lower the output level from the normal value when the screen is muted, the RGB signal output circuit 25 is used in the chroma IC 20. Is R
The output level of the GB signal is lowered below the normal value. Therefore,
Even if the output level of each color component varies, the CRT3
It is possible to reduce the coloring of black display at 0. Further, the above operation control can be realized without changing the hardware configuration, and is thus particularly suitable for mass production.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a television according to this embodiment.

FIG. 2 is a block diagram for explaining a main configuration of a chroma IC.

FIG. 3 is a flowchart showing an example of an operation procedure when the screen is muted.

FIG. 4 is a signal waveform diagram showing a change in output level during screen mute.

FIG. 5 is a flowchart showing another example of the operation procedure when the screen is muted.

[Explanation of symbols]

10 ... Tuner 11 ... Antenna 20 ... Chroma IC 21 ... Video amplifier circuit 22 ... OSD signal superimposing circuit 23 ... Horizontal deflection circuit 24 ... Vertical deflection circuit 25 ... RGB signal output circuit 30 ... CRT 31 ... Cathode amplifier 40 ... Microcomputer 41 ... OSD signal generation circuit

Claims (6)

[Claims] 1. An RGB signal output means that is connected to a CRT and outputs an RGB signal to the CRT based on a predetermined signal input, and an OSD signal superimposed on a predetermined video signal to the same R signal.
A chroma IC having an OSD signal superimposing means for outputting to a GB signal outputting means and a chroma IC for connecting to the chroma IC and for blanking an image output to the CRT based on the RGB signals to execute a screen mute. In a television including a screen mute device including a microcomputer having an OSD signal generating means for generating an OSD signal, the microcomputer outputs a fast blanking signal to the OSD signal superimposing means to execute the screen mute. Then, when the OSD signal generated by the OSD signal generating means is superimposed on the video signal, a cutoff control signal for lowering the cutoff level of the RGB output below the normal value is output to the RGB signal output means. Output level control means for controlling the cutoff control of the RGB signal output means. When the No. is inputted, the CR from the RGB signal output means
A television characterized in that the DC level of the RGB signals output to T is lowered below a normal value to reduce the white balance variation on the mute screen. 2. An RG that is connected to a video output device and outputs RGB signals to the video output device based on a predetermined signal input.
A chroma IC having a B signal output means and an OSD signal superposing means for superimposing an OSD signal on a predetermined video signal and outputting the superposed OSD signal to the RGB signal output means; and a chroma IC connected to the chroma IC and based on the RGB signal. A screen mute device comprising: a microcomputer having an OSD signal generating means for blanking an image output to a screen of an image output device to generate an OSD signal for executing the screen mute, wherein the microcomputer is the OSD signal superimposing device. The means is the above OSD
When the OSD signal generated by the signal generating means is superimposed on the video signal and output to the RGB signal output means,
A screen mute device comprising: output level control means for lowering an output level of an RGB signal output from the RGB signal output means to the video output device below a normal value. 3. The output level control means is the RGB
A cutoff control signal for lowering the cutoff level of RGB output from a normal value is output to the signal output means, and the same R
The screen mute device according to claim 2, wherein the GB signal output means lowers the output level of the RGB signals when the cutoff control signal is input. 4. The output level control means is the RGB
A brightness level control signal for lowering the brightness level of RGB output below a normal value is output to the signal output means, and the RGB signal output means changes the output level of the RGB signal when the same brightness level control signal is input. The screen mute device according to claim 2, wherein the screen mute device is lowered. 5. The microcomputer outputs a fast blanking signal to the effect that the screen mute is executed to the OSD signal superimposing means, and when the OSD signal superimposing means receives the fast blanking signal, The screen mute device according to any one of claims 2 to 4, wherein the OSD signal generated by the OSD signal generation means is superimposed on the video signal. 6. Normally, a chroma IC outputs an RGB signal based on a predetermined video signal to a video output device, thereby outputting a video corresponding to the video signal on the screen of the video output device, and muting the screen. At this time, O for blanking the same output image by the microcomputer connected to the same chroma IC
In the screen mute method of generating an SD signal, superimposing the OSD signal on the same video signal by the same chroma IC, and outputting an RGB signal based on the video signal on which the OSD signal is superposed to the same video output device, the microcomputer described above. Is a screen muting method, wherein the output level of the RGB signal output to the video output device is lowered below a normal value when the screen is muted.