JPH08256298A - Television receiver with PIP X-ray protector - Google Patents

Abstract

(57) [Abstract] [Purpose] When the high voltage rises due to a circuit failure, etc., when the main screen is out of synchronization for X-ray protection, at the same time, the display is turned off for X-ray protection from the sub-screen. Provided is a television receiver X-ray protection device with PIP. [Structure] When the high voltage rises, the main screen is unsynchronized and the screen is made to flow, so that the sub screen cannot be displayed by using the microcomputer controlling the on / off of the PIP.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a PIP (Picture).
The present invention relates to an X-ray protection device in a television receiver with In Picture).

[0002]

2. Description of the Related Art Conventionally, there is a television receiver which uses an X-ray protection device to turn off the operation of the television receiver when some abnormality occurs.

For example, when an abnormality occurs in the audio amplifier of the television receiver, in order to prevent the television receiver from being damaged due to the abnormality, the abnormality of the audio amplifier is detected and a detection signal thereof is separately provided. In addition to the X-ray protector described above, there is one that turns off the operation of the television receiver (see Japanese Patent Application Laid-Open No. 5-14752).

There is also one that turns off the television receiver by remote control data when the high-voltage circuit or the power supply circuit is abnormal (see Japanese Utility Model Laid-Open No. 3-115470).

Further, as a child screen signal processing circuit, an X-ray protection device in a television receiver with a PIP, which is configured to be connected to a video chroma jungle IC after synthesizing a parent screen and a child screen, has a circuit failure. In order to prevent the high voltage from rising due to such factors as radiating X-rays higher than specified, horizontal synchronization of the main screen is removed by the detection signal of the high voltage, and the display of the main screen is sent to the main screen ( (Unusable state) Randomly scatter the irradiation of the high-voltage beam to the phosphor to prevent the X-ray emission from the focused beam exceeding the specified value. The supply is stopped so that the display of the small screen is turned off so that X-ray emission from the small screen is eliminated. FIG. 3 is a circuit diagram showing the configuration of the above-described conventional television receiver with PIP. The low-voltage winding wound so as to correlate with the high-voltage winding of the flyback transformer FBT is a diode 1 and an electrolytic capacitor 2. Video Chroma Jungle IC6 with a built-in comparator at the connection point of voltage dividing resistors 4 and 5
Connected to the X-ray protection device terminal 7 of
It is connected to the video chroma jungle IC 6 via the comparator reference voltage circuit 10 including the Zener diode 9, and the connection point of the voltage dividing resistors 4 and 5 is the switching circuit including the Zener diode 11, the resistors 12 and 13 and the transistor 14. The vertical pulse input terminal 17 connected to the PIP IC 16 is grounded via the switching circuit 15. Reference numeral 18 is a horizontal pulse input terminal of the PIP IC 16, and 19 is a PIP IC by the microcomputer 20.
16 is a bus control input terminal, 21 is a CRT drive output terminal of the video chroma jungle IC6, and PIP
The parent / child screen composite signal is input from the video IC 16 to the video chroma jungle IC 6.

The operation of the conventional television receiver with PIP will be described below. When the high voltage rises due to a circuit failure or the like, the output voltage of the rectifier circuit 3 also rises in proportion thereto, and the detected voltage is taken out from the connection point of the voltage dividing resistors 4 and 5 and input to the video chroma jungle IC6. When the voltage is compared with the reference voltage from the comparator reference voltage circuit 10 and becomes equal to or higher than a predetermined voltage, the horizontal oscillation frequency in the video chroma jungle IC 6 becomes high, the main screen is out of synchronization, and the display flows. The X-ray protector has worked.

Since the high-voltage detection voltage at this time is a voltage divided by the voltage dividing resistors 4 and 5 having a resistance value variation (usually ± 10%), the voltage also varies.

FIG. 2 shows a CRT isodose curve (IS
FIG. 3 is a diagram showing ODOSE CURVE), and in the above-mentioned conventional television receiver with PIP, there is a variation in the high voltage at which the parent screen is out of synchronization. Curve A
Therefore, the high voltage curve B is obtained when the protective device removes the synchronization of the parent screen with the best sensitivity. In other words, the parent screen protection device works between the high voltage curves A and B.

On the other hand, with respect to the sub-screen which eliminates the X-ray emission by turning off the display by stopping the supply of the horizontal or vertical synchronizing signal, the switching circuit 15 controls the supply of the vertical pulse. The variations of the Zener diode 11, the resistors 12, 13 and the transistor 14 which form the switching circuit 15 are added, and the variation of the high detection voltage for controlling the switching circuit 15 is larger than that of the voltage dividing resistors 4 and 5. It will be big. Therefore, the variation of the high voltage for turning off the display of the child screen is between the high voltage curve A and the high voltage curve C in FIG. 2, and the variation is higher than between the high voltage curve A and the high voltage curve B where the protection device works for the parent screen. Becomes wider. The high pressure curve D shows the maximum high pressure under normal conditions.

[0010]

As described above, in the above-described conventional television receiver with PIP, the protective device works for the high-voltage variation and the small screen where the protective device works for the parent screen. When the high voltage rises due to a circuit failure or the like due to the difference in the high voltage, even if the main screen is out of synchronization for X-ray protection, the display is turned off at the same time for X-ray protection from the sub-screen. There is a problem that you can not.

The present invention solves the above problems, and an object of the present invention is to minimize the variation range of the operation of the X-ray protection apparatus.

[0012]

SUMMARY OF THE INVENTION The present invention rectifies the pulses from a flyback transformer FBT to remove horizontal synchronization of the parent screen in the event of a fault condition that may result in X-rays, It is added to the X-ray protection device terminal of the Chroma Jungle IC. In addition, by using a lock detection circuit that compares the parent screen with the H pulse (horizontal pulse), the video, chroma, and jungle ICs that change when the parent screen is out of synchronization are locked. The detection output is added to the microcomputer. If this voltage is HIGH (or LOW) when horizontal synchronization is normal, it changes to LOW (or HIGH) when it is out of the horizontal sync. Make sure that the inset screen is not displayed during HIGH).

[0013]

According to the present invention, the P signal is constructed so as to pass through the video chroma jungle IC after synthesizing the video signals for the parent screen and the child screen
In the television receiver with IP, the X-ray protection device can be operated so that the child screen is not displayed in synchronization with the loss of synchronization of the parent screen.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a PIP-equipped television receiver X-ray protection apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention. The same components as those of FIG. 3 showing a conventional example are designated by the same reference numerals and described.

The low-voltage winding wound so as to correlate with the high-voltage winding of the flyback transformer FBT has a rectifier circuit 3 composed of a diode 1 and an electrolytic capacitor 3, voltage dividing resistors 4, 5.
Connected to the X-ray protector terminal 7 of the video chroma jungle IC6 with built-in comparator, and the connection point of the voltage dividing resistors 4 and 5 is a comparator consisting of a resistor 8 and a zener diode 9. Reference voltage circuit 1
Connect to Video Chroma Jungle IC6 via 0,
Further, the lock detection terminal 22 of the video chroma jungle IC 6 that changes voltage when the parent screen is out of synchronization is connected to the microcomputer 20. 18 is IC for PIP 16
Horizontal pulse input terminal, 19 is a P by the microcomputer 20
The bus control input terminal 21 of the IP IC 16 and the CRT drive output terminal 21 of the video chroma jungle IC 6 are input with the parent-child screen composite signal from the PIP IC 16 to the video chroma jungle IC 6.

Next, the operation of the above embodiment of the present invention will be described. Regarding the X-ray protection from the main screen, as in the conventional example, when the high voltage rises due to a circuit failure or the like, the output voltage of the rectifier circuit 3 also rises in proportion to it, and the voltage divided by the voltage dividing resistors 4 and 5 is video. The horizontal oscillation frequency of the video chroma jungle IC6 is increased by being added to the X-ray protector terminal 7 of the chroma jungle IC6, and the parent screen is out of synchronization. At this time, regarding the X-ray protection from the child screen, the voltage of the lock detection terminal 22 of the video chroma jungle IC 6 becomes LOW (or HIGH) at the same time as the synchronization of the parent screen is lost, and the voltage change is received. Microcomputer 2
0 controls the PIP IC 16 which controls the on / off of the child screen from the bus control input terminal 19 of the PIP IC 16 through the bus control line, and turns off the child screen at the same time when the parent screen flows.

Therefore, in this case, the operation variation of the protective device when the parent screen and the child screen are abnormal is in the range of high voltage curve A to high voltage curve B in FIG.

[0019]

As described above, according to the present invention, an X-ray protection device can be provided even in a configuration in which a video signal for a parent screen and a child screen are combined for PIP and then passed through a video chroma jungle IC. It can be made to function so that the sub screen is not displayed at the same time when the main screen is out of sync.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of an X-ray protection device for a television receiver with PIP of the present invention.

FIG. 2 is a CRT isodose curve (ISODOSE
CURVE)

FIG. 3 is a circuit diagram showing a configuration of a conventional television receiver X-ray protector with PIP.

[Explanation of symbols]

 1 Diode 2 Electrolytic Capacitor 3 Rectifier Circuit 4,5 Voltage Dividing Resistor 6 Video Chroma Jungle IC 7 X-ray Protection Device Terminal 8, 12, 13 Resistor 9,11 Zener Diode 10 Comparator Reference Voltage Circuit 14 Transistor 15 Switching Circuit 16 PIP IC 17, 18 Input terminal 19 Bus control input terminal 20 Microcomputer 21 CRT drive output terminal 22 Lock detection terminal A Protective device High voltage curve at the worst sensitivity B Protective device High voltage curve at the best sensitivity C High-voltage curve when the inset screen disappears D Maximum high-voltage curve when normal

Claims (2)

[Claims] 1. When the X-ray protector is operating, a horizontal screen is fed to a higher horizontal frequency to lower the high voltage so that the main screen becomes an unusable screen, and the small screen uses a microcomputer that controls on / off of PIP. A PI that prevents the child screen from being displayed when the parent screen becomes unusable
Television receiver with P X-ray protector. 2. A flyback transformer FBT is rectified in order to remove the horizontal synchronization of the main screen when a failure condition in which X-rays may be emitted occurs, and video chroma,
In addition to the X-ray protection device terminal of the jungle IC, the lock detection output of the video / chroma / jungle IC whose voltage changes when the main screen is out of synchronization is added to the microcomputer. Or LOW), LOW (or HIG
H) is used to make LOW (or HIGH) by the microcomputer that controls the on / off of the small screen.
An X-ray protection device for a television receiver with PIP, characterized in that sometimes a sub-screen is not displayed.