JPH1042159A - Television receiver and control method for picture tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent baking of the picture tube due to a remaining spot caused on the occurrence of a fault in a deflection circuit. SOLUTION: A flyback pulse BPF from a deflection and high voltage circuit 17 is integrated by an integration circuit 18 and the presence of the flyback pulse BPF is discriminated based on an output level of the integration circuit 18. An output of the integration circuit 18 is given to a comparator 19 and the presence of the flyback pulse BPF is discriminated based on an output of the comparator 19. When an output level of the integration circuit 18 reaches a prescribed value or below and no flyback pulse BPF is detected, it is discriminated that a fault takes place in the deflection system to mute three primary color signals given to a picture tube 9 from a video signal processing circuit 7. Thus, baking of the picture tube due to a remaining spot is prevented.

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 more particularly to a method for coping with an abnormality in a deflection circuit.

[0002]

2. Description of the Related Art A television receiver is provided with a deflection circuit for forming a deflection current applied to a deflection coil of a picture tube based on a synchronization signal of a video signal. That is, the vertical and horizontal synchronization signals are extracted from the video signal.
In the vertical deflection system, a sawtooth wave synchronized with the vertical synchronization signal is formed, and the sawtooth wave synchronized with the vertical synchronization signal flows through the vertical deflection coil. In the horizontal deflection system, a sawtooth wave synchronized with the horizontal synchronization signal is formed by a circuit combining the horizontal output transistor and the diper diode, and the sawtooth wave synchronized with the horizontal synchronization signal is supplied to the horizontal deflection coil. At this time, a flyback transformer provided in parallel with the deflection coil generates a high voltage required for the picture tube. Then, the flyback pulse from the flyback transformer is fed back to the horizontal oscillation circuit, and an AFC circuit for stably maintaining the frequency of the sawtooth wave is configured.

[0003]

In a picture tube of a television receiver, a beam spot is controlled by a deflection current formed by such a deflection circuit. For this reason,
When an error occurs in the deflection circuit, a beam spot remains,
As a result, the picture tube may be burned.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a television receiver and a method of controlling the television receiver, which can prevent the picture tube from burning when an abnormality occurs in the deflection circuit.

According to the present invention, a deflecting means for forming a deflecting current based on a synchronizing signal of a video signal and applying the deflecting current to a deflecting coil of a picture tube, an abnormality detecting means for detecting an abnormality of the deflecting means, And a mute means for muting the video signal to the picture tube when is detected.

The present invention relates to a picture tube control method for forming a deflection current based on a video signal synchronization signal and applying the deflection current to a deflection coil of the picture tube to control a beam. This is a method for controlling a picture tube in which an abnormality of a deflection circuit for forming a deflection current based on the above is detected, and a video signal to the picture tube is muted when the abnormality of the deflection circuit is detected.

By detecting the presence or absence of a flyback pulse, an abnormality in the deflection system can be detected. When an abnormality in the deflection system is detected, the video signal is muted. Thereby, it is possible to prevent the picture tube from being burned due to the remaining spot.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a VTR-integrated television receiver to which the present invention is applied. In FIG. 1, reference numeral 1 denotes an AV input switch. A video signal and an audio signal from the tuner 2 are supplied to the AV input switch 1, and a video signal and an audio signal from the external video input terminal 3A and the external audio input terminal 4A and the external video input terminal 3 are supplied to the AV input switch 1.
A video signal and an audio signal are supplied from B and the external audio input terminal 4B. Further, a video signal and an audio signal reproduced by the VTR unit 5 are supplied to the AV input switch 1.

The AV input switch 1 controls the tuner 2, the external video input terminal 3A and the external audio input terminal 4A, the external video input terminal 3B and the external audio input terminal 4B, and the video signal and the audio signal from the VTR section 5 to the controller. 6 is to select a desired video signal and audio signal based on the control signal from the control unit 6. When displaying an image on a screen, a video signal from the AV input switch 1 is supplied to a video signal processing circuit 7, and an audio signal from the AV input switch 1 is
It is supplied to the audio signal processing circuit 8. When recording, a video signal and an audio signal from the AV input switch 1 are supplied to the VTR unit 5.

A video signal processing circuit 7 is a Y / C separation circuit for separating a luminance signal Y and a chroma signal C from the video signal from the AV input switch 1, and a color difference signal R from the chroma signal C.
A demodulation circuit for demodulating -Y and BY, a matrix circuit for forming three primary color signals R, G and B from the luminance signal Y and the color difference signals RY and BY are provided. The three primary color signals formed by the video signal processing circuit 7 are supplied to a picture tube 9. The horizontal synchronization signal and the vertical synchronization signal SYNC extracted by the video signal processing circuit 7 are supplied to the controller 6 and also to the deflection and high voltage circuit 17.

The deflection and high voltage circuit 17 forms a horizontal deflection current and a vertical deflection current of the picture tube 9 on the basis of the horizontal synchronization signal and the vertical synchronization signal sent from the video signal processing circuit 7. To create a high pressure applied to That is, the deflection and high voltage circuit 17 forms a sawtooth wave based on the vertical synchronization signal, and the sawtooth wave is supplied to the vertical deflection coil of the picture tube 9. Further, a horizontal output transistor and a diper diode are provided, and the saw-tooth wave based on the horizontal synchronizing signal flows through the horizontal deflection coil of the picture tube 9 by the horizontal output transistor and the damper diode. A flyback transformer is provided in parallel with the horizontal deflection coil, and a flyback pulse generated during a flyback period of the sawtooth wave flowing through the flyback transformer is rectified to form a high voltage applied to the picture tube 9.

[0012] The flyback pulse FBP from the flyback transformer is supplied to the video signal processing circuit 7 and also to the integration circuit 18. The flyback pulse FBP is, for example, a 5 V rectangular wave. The video signal processing circuit 7 uses the flyback pulse FBP to
FC control is performed so that a stable horizontal synchronization signal can be obtained.

In such a configuration, if an abnormality occurs in the deflection system of the deflection and high voltage circuit 17, a beam spot may remain and the picture tube 9 may be burned. Therefore, in this example, when an abnormality occurs in the deflection system, the video signal is muted. Whether or not an abnormality has occurred in the deflection system can be determined by detecting the presence or absence of the flyback pulse FBP.

That is, the flyback pulse FBP from the flyback transformer is supplied to the integration circuit 18.
The flyback pulse FBP is integrated by the integration circuit 18. The output of the integration circuit 18 is supplied to a comparator 19. The output of the comparator 19 is supplied to one end of the OR gate 20. The other end of the OR gate 20 is supplied with a mute signal MUTE from the controller 6. The mute signal MUTE from the controller 6 is a signal for muting the screen by the output of the controller 6. The output of the OR gate 20 is supplied to the mute circuit 21.

If there is no abnormality in the deflection system, a flyback pulse FBP is obtained, so that the output of the integration circuit 18 becomes higher than a predetermined level. When the output of the integrating circuit 18 is equal to or higher than a predetermined level, the output of the comparator 19 is at a low level.

If an abnormality occurs in the deflection system, the flyback pulse FBP cannot be obtained, and the output of the integrating circuit 18 falls below a predetermined level. When the output level of the integrating circuit 18 becomes lower than a predetermined level, the output of the comparator 19 becomes high level. When the output of the comparator 19 becomes high level and it is detected that the output level of the integration circuit 18 has fallen below a predetermined level, a mute signal is given to the mute circuit 20 via the OR gate 20. With this mute signal, R, G,
The level of the B primary color signal is lowered to the ground level, and the video signal is muted.

The audio signal processing circuit 8 includes an audio amplifier for amplifying the audio signal, an electronic volume for volume control, and the like. The electronic volume for volume control is controlled by the controller 6. The output of the audio signal processing circuit 8 is supplied to a speaker 10.

The VTR section 5 is a helical scan type VTR.
It has a TR configuration. That is, the VTR unit 5 records and reproduces a video signal by a rotary head. The VTR unit 5 includes a mechanical unit such as a drive system of a tape or a drum, a circuit unit of a recording system that FM-modulates a luminance signal Y and converts a chroma signal C into a low frequency, and an FM from a reproduced signal from a rotary head. It extracts the modulated luminance signal and the low-frequency conversion chroma signal, performs FM demodulation of the luminance signal, frequency-converts the chroma signal to the original carrier frequency, and reproduces a circuit section of a reproduction system for reproducing a video signal from a magnetic tape. Have. This VTR unit 5 is controlled by a VTR controller 11.

The controller 6 receives an input from a remote commander 13 via a light receiving section 12. By operating the remote commander 13, input switching, channel setting, volume adjustment, and the like can be performed. The controller 6 and the VTR controller 11 are bidirectionally connected to each other.
The operation setting of the R unit 5 can be performed.

A display control signal is generated from the controller 6. This display control signal is applied to the display generation circuit 14.
Supplied to The output of the display generation circuit 14 is supplied to the video signal processing circuit 7. The display generation circuit 14 displays the setting state of the reception channel, volume, and the like on the screen. Note that a nonvolatile memory 15 is provided to store various adjustment data. Then, the nonvolatile memory 15,
The video signal processing circuit 7 is connected.

When displaying a television broadcast screen, a video signal and an audio signal from the tuner 2 are selected by the AV input switch 1 as inputs to the video signal processing circuit 7 and the audio processing circuit 8. A channel switching signal is supplied from the controller 6 to the tuner 2. The television broadcast signal received by the antenna 16 is supplied to the tuner 2. From the television broadcast signal received by the antenna 16 by the tuner 2,
A signal of a desired channel is selected. Then, the tuner 2 demodulates the video signal and the audio signal from the signal of the reception channel. The demodulated video signal is
The signal is supplied to the video signal processing circuit 7 via the AV input switch 1. The output of the video signal processing circuit 7 is supplied to the picture tube 9, and a screen based on the received television broadcast is displayed on the picture tube 9. Also, the demodulated audio signal is
It is supplied to the audio signal processing circuit 8. Audio signal processing circuit 8
Is supplied to the speaker 10, and audio based on the received television broadcast is output from the speaker 10.

External video equipment such as a VTR, a video disc player, a satellite broadcast tuner, and the like are connected to the external video input terminal 3A and the external audio input terminal 4A, and the external video input terminal 3B and the external audio input terminal 4B. When projecting signals from these devices,
An external video input terminal 3 is used as an input to the video signal processing circuit 7 and the audio processing circuit 8 by the V input switch 1.
The video signal and the audio signal from A and the external audio input terminal 4A or the external video input terminal 3B and the external audio input terminal 4B are selected. The selected video signal is supplied to the video signal processing circuit 7 via the AV input switch 1. The output of the video signal processing circuit 7 is supplied to the picture tube 9, and a picture based on a video signal from an external device is displayed on the picture tube 9. The selected audio signal is supplied to the audio signal processing circuit 8 via the AV input switch 1. The output of the audio signal processing circuit 8 is supplied to the speaker 10, and the audio based on the audio signal from the external device is output from the speaker 10.

When the screen reproduced from the VTR unit 5 is displayed, the video signal and the audio signal from the VTR unit 5 are input to the video signal processing circuit 7 and the audio processing circuit 8 by the AV input switch 1. Selected.
The selected video signal is supplied to the video signal processing circuit 7 via the AV input switch 1. The output of the video signal processing circuit 7 is supplied to the picture tube 9 and the picture tube 9
A screen based on the video signal from the unit 5 is displayed. The selected audio signal is supplied to the audio signal processing circuit 8 via the AV input switch 1. The output of the audio signal processing circuit 8 is supplied to the speaker 10, and the audio based on the audio signal from the VTR unit 5 is output from the speaker 10.

When recording a television broadcast screen, a video signal and an audio signal from the tuner 2 are selected by the AV input switch 1 as inputs to the VTR section 5. The tuner 2 selects a signal of a desired channel from television broadcast signals received by the antenna 16, and demodulates a video signal and an audio signal from the signal of the received channel. The demodulated video signal and audio signal are supplied to the VTR unit 5 via the AV input switch 1. By the VTR unit 5,
A video signal and an audio signal based on the reception channel are recorded on a video tape.

When recording a signal from a device from the external video input terminal 3A and the external audio input terminal 4A, or from the external video input terminal 3B and the external audio input terminal 4B, the AV input switch 1 causes the VTR unit 5 to record.
The video signal and the audio signal from the external video input terminal 3A and the external audio input terminal 4A, or the external video input terminal 3B and the external audio input terminal 4B are selected as the input to the terminal. The selected video signal and audio signal are transmitted via the AV input switch 1 to the VT
It is supplied to the R section 5. The VTR unit 5 records a video signal and an audio signal based on the reception channel on a video tape.

In the above-described example, the presence or absence of the flyback pulse FBP is detected by the integration circuit 18 and the comparator 19 to detect an abnormality in the deflection system. However, the flyback FBP is supplied to the controller 6 and 6, the abnormality of the deflection system may be determined. In this case, for example, it is possible to determine the abnormality of the deflection system by detecting the cycle of the flyback transformer FBP.

FIG. 2 is a flowchart showing the processing at that time. In FIG. 2, it is determined whether or not the power is turned on (step ST1). When the power is turned on, it is determined whether or not an abnormality has occurred in the deflection system. Whether or not an abnormality has occurred in the deflection system can be determined by measuring the period of the flyback pulse FBP. If it is determined that an abnormality has occurred in the deflection system,
The video signal is muted (step ST3). As described above, when an abnormality occurs in the deflection system, the image signal is muted to prevent the picture tube 9 from being burned due to the remaining spot.

In the above-described example, a television receiver integrated with a VTR has been described, but the present invention is not limited to such a television receiver integrated with a VTR. The present invention can be similarly applied to a television receiver integrated with a normal television receiver, a monitor receiver, a video CD, a video disk, and a DVD playback device.

[0029]

According to the present invention, an abnormality in the deflection system is detected by detecting the presence or absence of a flyback pulse, and when an abnormality in the deflection system is detected, the video signal is muted. Thereby, it is possible to prevent the picture tube from being burned due to the remaining spot.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a VTR-integrated television receiver to which the present invention is applied.

FIG. 2 is a flowchart used to describe a VTR-integrated television receiver to which the present invention is applied.

[Explanation of symbols]

1 ... AV input switch, 6 ... Controller, 7
... Video signal processing circuit, 9 ... CRT, 17 ...
Deflection and high voltage circuits

Claims (6)

[Claims] 1. A deflecting means for forming a deflecting current based on a synchronizing signal of a video signal and applying the deflecting current to a deflecting coil of a picture tube; an abnormality detecting means for detecting an abnormality of the deflecting means; A mute means for muting the video signal to the picture tube when an abnormality is detected. 2. The television according to claim 1, wherein the abnormality detecting means determines whether an abnormality has occurred in the deflection circuit by detecting the presence or absence of a flyback pulse from the deflection circuit. John receiver. 3. The television according to claim 1, wherein the abnormality detecting means determines whether an abnormality has occurred in the deflection circuit by measuring a period of a flyback pulse from the deflection circuit. John receiver. 4. A picture tube control method, comprising: forming a deflection current based on a video signal synchronization signal; and providing the deflection current to a deflection coil of the picture tube to control a beam. A method of controlling a picture tube, comprising: detecting an abnormality in a deflection circuit that forms a deflection current based on the image signal; and muting a video signal to the picture tube when the abnormality in the deflection circuit is detected. 5. The picture tube control method according to claim 4, wherein the abnormality of the deflection circuit is determined by detecting the presence or absence of a flyback pulse from the deflection circuit. 6. The picture tube control method according to claim 4, wherein the abnormality of the deflection circuit is determined by measuring a period of a flyback pulse from the deflection circuit.