JPH099279A - Degaussing coil driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a harmful wave outputted in an electromagnetic field generated by the operation of a degaussing coil used in an information output device by adopting a circuit physically interrupting an AC power supply and the degaussing coil. SOLUTION: An AC power supply application section 10 applies an AC power supply to a degaussing coil L3 used to eliminate a magnetic field generated in a shadow mask via switches RS11, RS12. The operation of the degaussing coil L3 is controlled by the control signal outputted from a control signal generating section 200. When the degaussing coil L3 is not active, the connection terminal between the AC power supply application section 10 and the degaussing coil L3 is surely parted by a relay RY 10 thereby eliminating a harmful wave outputted by the electromagnetic field.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a degaussing coil driving device, and more particularly, to prevent harmful waves by removing an electric field by a degaussing coil mounted on a computer monitor, a color television, etc. Of the degaussing coil driving device.

[0002]

2. Description of the Related Art Generally, a color television, a monitor or the like outputs a desired image using a cathode ray tube. Then, when an electron beam emitted from the cathode by three electron guns is accelerated and generated on the anode side, the electrons emitted by the electron gun are sucked into the anode to which a high voltage (+) voltage is applied. And collide with the anode surface at high speed. Therefore, the electrons collide with the phosphor screen coated with the red, green, and blue phosphors at high speed, and the light corresponding to the collided phosphors emits light to obtain a desired image. At this time, a shadow mask in which many holes are formed between the fluorescent screen and the electron gun is attached, and the electron beams emitted from the electron gun through the holes of the shadow mask emit red, green, and blue fluorescent light, respectively. It collides with the surface and makes the corresponding image.

However, when the state of the charged shadow mask is not completely restored to the normal state due to the collision of the electron beam, a magnetic field is formed on the surface of the shadow mask, so that the electron beam emitted from the electron gun is emitted. Does not exactly pass through the corresponding hole of the shadow mask, but a part of the electron beam passes through another hole in the vicinity. For this reason, there is a problem in that the image quality is deteriorated due to color interference in which the red, green, and blue phosphors do not collide accurately with each other and a collision phenomenon occurs with other phosphors. Therefore, in order to prevent the color interference phenomenon that occurs before the state of the shadow mask returns to the normal state as described above, by attaching a degaussing coil separately to remove the magnetic field formed on the surface of the shadow mask, It prevents the deterioration of image quality due to unnecessary hue.

Next, the driving operation of the conventional degaussing coil will be described with reference to FIG. FIG. 2 is a circuit diagram of a conventional degaussing coil driving device. An AC power supply unit 10 and a control signal generator 20 for outputting a removal signal for removing a magnetic field generated in the shadow mask, and a high voltage operated by a control signal output from the control signal generator 20. RY1 for inducing a voltage, a degaussing coil L3 for inducing a high voltage according to the operation of the relay RY1, a degaussing coil L3, one side terminal is connected, and the (-) terminal is connected to the other side terminal. It comprises a thermistor Q1 and a drive switch SW1 for manually driving the degaussing coil L3 whose connection state is changed according to the operation of the user. Further, the AC power supply unit 10 is (+)
One end of each of the coils L1 and L2, one end of which is connected to the other end, and the other end of which is connected to the other end of the coil L1 and L2. It is composed of C1 and C2 and a capacitor C3 which is connected to the other terminals of the coils L1 and L2, respectively.

The control signal generator 20 has a resistor R1 having one terminal connected to the power supply Vcc and the other terminal connected to the drive switch SW1, and a diode D1 having a cathode terminal connected to the power supply Vcc. And a resistor R2 whose one terminal is connected to the anode terminal of the diode D1 and whose other terminal is connected to the other terminal of the resistor R1.
And a capacitor C4 whose one terminal is connected to the anode terminal of the diode D1 and whose other terminal is grounded.
A Zener diode ZD1 having a cathode terminal connected to one side terminal of the capacitor C4, and a capacitor C5 having one side terminal connected to the anode terminal of the Zener diode ZD1 and the other side terminal grounded,
A transistor T1 whose base terminal is connected to the anode terminal of the Zener diode ZD1 and whose emitter terminal is grounded, a resistor R3 whose one terminal is connected to the power supply Vdd, and the other terminal of the resistor R3 and A capacitor C6 having one terminal connected to the collector of the transistor T1 and the other terminal grounded; a transistor T2 having the base terminal connected to the collector terminal of the transistor T1 and the emitter terminal grounded; The diode D2 has a cathode terminal connected to the power supply Vdd and an anode terminal connected to the collector terminal of the transistor T2. The relay RY1
Is connected to the relay coil RL1 connected to the diode D2 of the control signal generator 20 and the other side terminal of the coil L1 of the AC power supply unit 10 is connected to one side of the degaussing coil L3. The relay switch RS1 is connected to the other terminal.

The driving operation of the prior art degaussing coil thus configured is as follows. (+) And (-)
When AC power is supplied through the ends, the coils L1 and L2
After being filtered through a filter composed of the capacitors C1 and C2, it is applied by a rectifier (not shown) and converted into a DC power supply necessary for operation. Then, when the DC power supplies Vcc and Vdd of each level necessary for the operation of the cathode ray tube are applied, the degaussing coil L3 operates and the electric field generated on the surface of the shadow mask is removed to improve the image quality. Therefore, when the power source Vcc is supplied, the resistance R
1, the capacitor C4 is applied by the voltage applied through R2.
The charging operation of starts. When the charged state of the capacitor C4 does not reach a certain set state, the Zener diode ZD1 is turned off, and the transistor T1 is kept turned off. Then, as the transistor T1 is turned off, a high level voltage of "H" is applied to the base terminal of the transistor T2, so that the transistor T2 is turned on and the relay RY1 operates. The relay RY1
By this operation, the connection state of the relay switch RS1 is changed to the ON state, and an AC signal flows through the degaussing coil L3 connected to the (+) terminal of the AC power supply unit 10, so that the degaussing coil L3 receives an instantaneous high voltage. A voltage is induced. Therefore, the high current flowing through the degaussing coil L3 removes the electric field formed in the shadow mask, and a clear image can be output.

However, when a certain time elapses and the charged state of the capacitor C4 reaches a set state, the state of the Zener diode ZD1 is changed to the conductive state and the transistor T1 is turned on. The transistor T1
The voltage state applied to the base terminal of the transistor T1 by the turn-on operation is changed to a low level "L" state, and the operation of the relay RY1 is stopped. Therefore,
Since the AC power supply flowing through the degaussing coil L3 is cut off, the operation of the degaussing coil L3 is stopped. After the power supplies Vcc and Vdd necessary for the operation are applied as described above, the degaussing coil L3 can be operated during the time set according to the charging time of the capacitor C1. When the user operates the degaussing coil L3 as necessary, the user turns on the drive switch SW1. Therefore, the charge stored in the capacitor C4 is discharged by the resistor R2 and the switch SW1 that is turned on, and thus the Zener diode Z
D1 is turned off. Therefore, the transistor T1 is turned on by the off state of the Zener diode ZD1 to drive the relay RY1, and thus the degaussing coil L3.
The current starts to flow. Through the above operation, the magnetic field generated on the surface of the shadow mask can be removed.

[0008]

However, the operation of the degaussing coil L3 which is temporarily operated to generate a strong magnetic field is stopped when the operation of the relay RY1 is stopped.
A strong electric field continues to be formed in the induced degaussing coil L3. In particular, after the operation of the degaussing coil L3 is stopped, one terminal of the degaussing coil L3 is continuously connected to the (−) end of the AC power supply unit 10, so that a strong electric field remains. The strong electromagnetic field generated by the operation of the degaussing coil as described above causes a harmful wave which is very bad for the human body, and causes a problem that it is a great obstacle to comply with various regulations regarding electromagnetic waves.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to provide a harmful wave output by an electromagnetic field generated by the operation of a degaussing coil used in an information output device. In order to eliminate the above, it is to provide a degaussing coil driving device for preventing harmful waves.

[0010]

The above-mentioned object can be achieved by the invention described in each claim. That is, the characteristic configuration of the degaussing coil driving device for preventing harmful waves according to the present invention is that the degaussing coil drive device to which an AC power source is applied and the degaussing coil used to remove the magnetic field generated in the shadow mask are operated. A control signal generator that outputs a control signal to control, and an operating state that is varied according to the control signal output from this control signal generator to control the operating state of the degaussing coil And a switching means for physically disconnecting the connection terminal of the degaussing coil. With such a configuration, when the operation of the degaussing coil is stopped by the operation of the switching means, the switching means, for example, a switch, is surely separated from the AC power supply application section. When the present invention is configured as described in claims 2 and 3,
The above object is more preferably achieved.

[0011]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a circuit diagram of the degaussing coil driving device according to the present embodiment. In the figure, the same parts as those of the conventional degaussing coil driving device are designated by the same reference numerals. This degaussing coil driving device includes an AC power supply applying section 10 and a control signal generating section 200 for outputting a removal signal for removing a magnetic field generated in the shadow mask.
And a relay RY10 that is a switching means that is operated by a control signal output from the control signal generator 200 so as to induce a high voltage, and the relay RY.
Degaussing coil L for inducing high voltage according to the operation of 10.
3 and one terminal is connected to this degaussing coil L3 (-)
The thermistor Q1 has a terminal connected to the other side terminal, and a drive switch SW1 for manually driving the degaussing coil L3 whose connection state is changed according to the operation of the user. The AC power supply unit 10 is
The coils (L1 and L2) whose one-side terminals are connected to the (+) and (-) ends, respectively, and the one-side terminals are connected to the other-side terminals of these coils L1 and L2, respectively, and the other-side terminals are grounded. Capacitors C1 and C2 and the coil L1,
Capacitor C connected to the other terminal of L2
3 and 3.

The control signal generator 200 has a power source Vdd.
And a resistor R11 whose one terminal is connected to
A resistor R12 in which one terminal is connected to the other terminal of 11
A capacitor C11 whose one side terminal is connected to the other side terminal of this resistor R12 and whose other side terminal is grounded; a resistor R13 whose one side terminal is connected to the power source Vdd; Transistor T11 with collector terminal connected to side terminal and emitter terminal grounded
A Zener diode ZD11 having a cathode terminal connected to the other terminal of the resistor R12 and an anode terminal connected to the base terminal of the transistor T11; and a diode D11 having a cathode terminal connected to the power supply Vdd, A collector terminal is connected to the anode terminal of the diode D11, a base terminal is connected to the collector terminal of the transistor T11, and an emitter terminal is grounded. A transistor T12 is connected to the base terminal of the transistor T12. The capacitor C12 is connected to the other terminal and is grounded.

The relay RY10 has a relay coil RL11 having one terminal connected to the power supply Vdd and the collector terminal of the transistor T12 of the control signal generating section 200 connected to the other terminal, and an AC power supply section 10. Second relay switch RS11 in which one side terminal is connected to the other side terminal of the coil L2 and the other side terminal is connected to one side terminal of the thermistor Q1, and the other side terminal of the coil L1 of the AC power supply unit 10. And a second relay switch RS12 having one side terminal connected to one side and the other side terminal connected to one side terminal of the degaussing coil L3.

Next, the operation of the degaussing coil driving device will be described. When the AC power required for operation is applied, the coil L
After being filtered by a filter composed of 1 and L2 and capacitors C1 and C2, they are supplied to necessary devices. Then, the power supply V for operating the degaussing coil L3
When dd is supplied, the control signal generator 200 operates to remove the magnetic field formed in the shadow mask. Therefore, when the power source Vdd is applied, the charging operation of the capacitor C11 is started, and the capacitor C11 is charged.
The operating state of the Zener diode ZD11 changes according to the charging state of.

When the charge state of the capacitor C11 is not reached to a certain set state, the Zener diode ZD1
Since the state of 1 is a non-conduction state, the transistor T11
Is turned off. When the transistor T11 is turned off, the resistor R13 and the capacitor C1
Since the voltage applied to the base terminal of the transistor T12 via 2 becomes the high level “H” state, the transistor T12 is turned on. Therefore, the current of the power supply Vdd flows to the transistor T12 via the relay coil RL11 of the relay RY10 due to the turn-on operation of the transistor T12, so that the relay RY10 changes to the operating state. Therefore, the connection state of the first and second relay switches RS11 and RS12, which maintains the OFF state when the relay RY10 is in the non-operation state, changes to the ON state.

By the operation of the relay RY10, an AC power source flows through the degaussing coil L3, a high voltage is induced in the degaussing coil L3, and a high current flows. When the charge state of the capacitor C11 reaches the set state after the set time elapses, the state of the Zener diode ZD11 is changed to the conductive state,
Turn on transistor T11. Due to the turn-on operation of the transistor T11, the transistor T12
The state of is also turned off and the operation of the relay RY10 is stopped, so that the operation of the degaussing coil L3 is stopped. When the user needs to drive the degaussing coil L3, the user operates the drive switch SW1. Therefore, the electric charge charged in the capacitor C11 is discharged through the drive switch SW1, and the Zener diode ZD11 becomes non-conductive.

The change in the state of the Zener diode ZD11 turns off the transistor T11. Therefore, the relay RY10 operates by the turn-on operation of the transistor T12 due to the turn-off of the transistor T11, and the degaussing coil L3 operates. At this time, when the drive switch SW1 is turned off and the charged state of the capacitor C11 reaches the set state, the operation of the degaussing coil L3 is stopped. As mentioned above, relay R
When the operation of the degaussing coil L3 is stopped by the operation of Y10, it is completely separated from the AC power supply application unit 10 by the switches RS11 and RS12 of the relay RY10.

[0018]

As described above, according to the present invention, the electromagnetic field remaining in the degaussing coil L3 can be reliably removed by the inductive action of the degaussing coil L3, and the generation of harmful waves can be reduced.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a degaussing coil driving device.

FIG. 2 is a circuit diagram of a conventional degaussing coil driving device.

[Explanation of symbols]

 10 AC power supply applying section 200 Control signal generating section C11 Capacitor L3 Degaussing coil R11, R12 Resistance RS11 First relay switch RS12 Second relay switch RY10 Switching means Q1 Thermistor T11 First switching element T12 Second switching element Vdd power supply ZD11 Zener diode

Claims (3)

[Claims] 1. A control signal for outputting a control signal for controlling an operating state of an AC power supply unit (10) to which an AC power supply is applied and a degaussing coil (L3) used for removing a magnetic field generated in a shadow mask. The operation state of the degaussing coil (L3) is controlled by changing the operating state in accordance with the generation section (200) and the control signal output from the control signal generation section (200). During operation, the AC power supply unit (10) and the degaussing coil (L
A degaussing coil drive device comprising: a switching means (RY10) for physically disconnecting the connection terminal of 3). 2. The control signal generator 200 includes a capacitor C11 which starts a charging operation when a power source Vdd is applied through resistors R11 and R12, and the capacitor C11 is connected to the capacitor C11. Capacitor (C1
1) Zener diode (ZD11) whose operating state is changed according to the charged state, and first switching which controls the flow of the power supply (Vdd) by changing the conducting state according to the operating state of this Zener diode (ZD11) The element (T11) and the first switching element (T1
The degaussing coil driving device according to claim 1, further comprising: a second switching element (T12) whose conduction state is changed according to the operation state of 1) to control the operation of the switching means (RY10). 3. The switching means (RY10) comprises:
One terminal is connected to the power source (Vdd) and the second switching element (T1) of the control signal generator (200).
2) The relay coil (RL1
1), a first relay switch (RS11) having one side terminal connected to the (−) end of the AC power supply applying section (10) and the other side terminal connected to the degaussing coil (L3), and the AC The second relay switch (RS12), wherein one side terminal is connected to the (+) end of the power supply section (10) and the other side terminal is connected to the degaussing coil (L3).
The degaussing coil driving device described.