JP3217588B2 - Method of suppressing unnecessary electric field - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing an unnecessary alternating electric field generated from a deflection yoke device, a flyback transformer or the like in a cathode ray tube display device using a cathode ray tube. The present invention relates to a method for suppressing an unnecessary electric field that can reduce adverse effects on surrounding electronic devices and humans due to an extremely low frequency (5 Hz to 400 kHz) electric field leaking from a device.

[0002]

2. Description of the Related Art In recent years, unnecessary electromagnetic fields leaking from cathode ray tube display devices and the like which are frequently used as computer terminals have been regarded as a problem. It is pointed out that these unnecessary electromagnetic fields may cause radio interference to surrounding electronic devices and may have a negative effect on humans or animals on health. Because it is.

[0003] In order to reduce obstacles and adverse effects on electronic equipment and humans due to these unnecessary electromagnetic fields, for example, an alternating electric field (A) according to the Swedish MPR-II standard is used.
EF) standards are defined. The standard recommends that unnecessary electric fields leaking from the cathode ray tube display be suppressed to a certain amount or less. Specifically, it is recommended that the value of the electric field strength measured at a distance of 0.5 m from the tube surface of the cathode ray tube display be 2.5 V / m or less.

[0004]

By the way, in order to satisfy the above-mentioned MPR-II standard, a cathode ray tube display device uses a horizontal deflection frequency pulse generated from a deflection yoke device or a flyback transformer, or a cathode ray tube. It is necessary to prevent or reduce unnecessary leakage of an electromagnetic field caused by a high-voltage power supply or the like including a ripple of a horizontal deflection period supplied to the anode electrode. Conventionally, means for preventing or reducing unnecessary electromagnetic field leakage include means for covering the entire cabinet of a cathode ray tube display device with a metal member, and glass plates provided with a conductive mesh on the cathode ray tube surface. Means are provided to electrically connect the conductive mesh to the cabinet of the cathode ray tube display device.

However, in the former of these conventional methods, it is impossible to cover the entire surface of a cathode ray tube display device having a visible display portion with a metal member, while the latter is a glass plate provided with a conductive mesh. When using the CRT, not only the structure of the cathode ray tube display becomes complicated, but also the cathode ray tube display itself becomes expensive, and it is difficult to obtain a cathode ray tube display satisfying the MPR-II standard. Met.

An object of the present invention is to provide an inexpensive cathode ray tube display device which can solve these difficulties by simple means, has a simple structure and is inexpensive.

[0007]

SUMMARY OF THE INVENTION A cathode ray tube display device includes :
One end is connected to lead terminal A and the other end is connected to lead terminal B.
Next winding M1, one end to lead terminal C, the other end to high voltage rectification
Connected to anode terminal E via diode 5 and internal resistor 6
Connected to the secondary terminal M2, one end connected to the lead terminal D, and the other end connected to the anode terminal E via the smoothing capacitor 4.
One-turn tertiary winding M that generates a negative pulse S with a flat deflection period
And molded integrally with an insulating resin.
High-voltage power supply HV output from the flyback transformer 2
To cancel the ripple of the high-voltage power supply or cancel the unnecessary electric field due to the pulse of the horizontal deflection period, thereby reducing the unnecessary electric field leaking from the cathode ray tube display device.

It is more effective to provide a pulse voltage adjusting means or a phase adjusting means in the tertiary winding M3 .

[0009]

The number of windings that generates the negative pulse S of the horizontal deflection period is one.
With the tertiary winding M3 is disposed, the tertiary winding M3
A high voltage power supply in which a negative pulse S generated from the superimposed signal is superimposed via a smoothing capacitor 4 is applied to an anode electrode of a cathode ray tube display.
Since supplied, unnecessary electric field is reduced ripple in the horizontal deflection period included in the high voltage power source is canceled. Further, from the negative pulse S , an electric field for canceling an unnecessary electric field due to a pulse from the deflection yoke or the like is generated, and an unnecessary electric field leaking from the cathode ray tube display device is reduced. The effect on surrounding electronic devices and humans is greatly reduced.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS.
FIG. 1 is a circuit diagram for explaining a method for suppressing an unnecessary electric field according to the present invention, and FIGS. 2A and 2B are waveform diagrams showing a ripple and a negative pulse included in a high-voltage power supply, respectively.

In FIG. 1, reference numeral 2 denotes a flyback transformer. The flyback transformer 2 has lead terminals A and B of a primary winding M1, one lead terminal C of a secondary winding M2,
One-turn tertiary winding that generates a negative pulse S with a horizontal deflection period
M3 , one lead terminal D, a smoothing capacitor 4 (3,000 to 6,000 pF) for smoothing a high-voltage power supply, and an anode terminal E for supplying a high-voltage power supply smoothed by the smoothing capacitor 4 to an anode electrode of a cathode ray tube display device. Are arranged. 5 is a high voltage rectifier diode, and 6 is an internal resistance.

The lead terminals A, B, C,
D, E or smoothing capacitor 4 and high-voltage rectifier diode 5
Each of them is integrally molded with an insulating resin to form the flyback transformer 2. The negative pulse S
The tertiary winding M3 that generates the signal is composed of a one-turn winding wound around the core of the flyback transformer 2.
A negative pulse S having a waveform as shown in FIG.
Occurs.

In the flyback transformer 2 configured as described above, the output from the secondary winding is smoothed by a smoothing circuit including a high-voltage rectifier diode 5, an internal resistor 6, and a high-voltage smoothing capacitor 4, and at the same time, the smoothing capacitor 4 , The negative pulse S of the horizontal deflection period H is superimposed.

Accordingly, when the high-voltage power supply HV supplied to the anode electrode of the cathode ray tube display includes a ripple P having a waveform as shown in FIG.
Is canceled by the negative pulse S, the amplitude changes from P1 to T1, for example. As a result, the high-voltage power supply H
Leakage of an unnecessary electric field due to the ripple P included in V decreases similarly to a change in the amplitude of the ripple P.

On the other hand, since the electric field for canceling the unnecessary electric field due to the pulse of the horizontal deflection period generated from the deflection yoke or the like is generated by the negative pulse S, the unnecessary electric field leaking from the cathode ray tube display is reduced. As a result,
The electric field strength which was 2.7 V / m in the conventional method was reduced to 1.8 V / m in the embodiment of the present invention, and the MPR-II
The standard was fully satisfied.

As described above, according to the present invention, the unnecessary electric field leaking from the cathode ray tube display device is reduced not only when the high-voltage power supply includes the ripple but also when the high-voltage power supply does not include the ripple. It is now possible to do that.

If the voltage value or the phase of the negative pulse of the horizontal deflection period generated from the tertiary winding M3 can be adjusted by a variable resistor, the ripple component P included in the high-voltage power supply HV is completely canceled. It becomes possible to do.

[0018]

According to the present invention, a negative pulse generating means having a horizontal deflection period is provided in a cathode ray tube display, and the negative pulse generated in the negative pulse generating means is passed through a smoothing capacitor to the cathode ray tube display. By the simple means of superimposing on the anode electrode, the unnecessary electric field leaking from the cathode ray tube display device, which was impossible with the conventional method, can be reduced. As a result, an inexpensive cathode ray tube display device having a simple structure that satisfies the MPR-II standard provided for an extremely low frequency electric field can be obtained, and has a great practical effect.

[Brief description of the drawings]

FIG. 1 is a circuit diagram illustrating a method for suppressing an unnecessary electric field according to the present invention.

2A and 2B show a ripple and a negative pulse included in a high voltage power supply. FIG. 2A is a waveform diagram showing a ripple and a ripple state canceled by the pulse of the high voltage power supply, and FIG. 2B is a negative pulse. FIG.

[Explanation of symbols]

2 Flyback transformer 4 Smoothing capacitor 5 High voltage rectifier diode 6 Internal resistance M1 Primary winding M2 Secondary winding M3 Tertiary winding A, B, C, D lead terminal E Anode terminal P, T Ripple S Negative pulse HV High voltage power supply

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 9/29 G09G 1/00 H01F 38/42 H02M 7/06 H01J 29/00-29/96

Claims (2)

(57) [Claims] 1. A method for suppressing an unnecessary electric field of a horizontal deflection period leaking from a cathode ray tube display device, wherein one end is connected to a lead.
Primary winding M1 with the other end connected to terminal A and lead terminal B
And one end to the lead terminal C and the other end to a high-voltage rectifier diode.
5 connected to the anode terminal E via the internal resistor 6
A horizontal deflection period in which the winding M2 and one end are connected to the lead terminal D and the other end is connected to the anode terminal E via the smoothing capacitor 4
And a tertiary winding M3 having one turn to generate a negative pulse S of
Flybar integrally molded with insulating resin
High-voltage power supply HV output from the power transformer 2 to a cathode ray tube
And reducing the unnecessary electric field leaking from the cathode ray tube display device to the anode electrode . 2. The method for suppressing an unnecessary electric field according to claim 1, wherein the tertiary winding M3 is provided with a pulse voltage adjusting means or a phase adjusting means.