JPH08256348A - Degaussing coil - Google Patents

Abstract

PURPOSE: To suppress disturbing radiation by winding a conductive tape to the degaussing coil entirely to prevent undesired disturbing radio wave from a deflection circuit, a power supply circuit and a video circuit or the like and the emission of an electromagnetic wave and an electric field wave. CONSTITUTION: A conductive tape 2 being a nonmagnetic material is wound to the outer sheath of the degaussing coil 1. In order to avoid insulation breakdown, an insulation tape 5 is wound in advance. Since the overlapped conductive tapes 2 causes short-circuit, the tape 2 is wound overlappingly through an insulation material 7 to reduce the effect. Moreover, an earthing circuit 6 to connect electrically the conductive tape 2 to ground is provided to apply electrostatic shielding to the coil 1. The conductive tape 2 is used for the outer sheath of the coil 1 and the coil 1 is shielded, then the reduction in the magnetic reluctance is prevented and disturbing radiation from the coil 1 itself is suppressed by keeping the electrostatic shield effect. Furthermore, a metallic case covering a cathode ray tube is not required, the display monitor is made light in its weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a degaussing circuit for a cathode ray tube display, including a deflection circuit, a power supply circuit, a video circuit,
The present invention relates to a degaussing coil that can prevent unnecessary interference radio waves, electromagnetic waves, and electric field waves from radiating from control circuits and the like.

[0002]

2. Description of the Related Art In recent years, cathode ray tube displays have been widely used not only for TVs but also for personal computer monitors, workstation monitors and the like.

In particular, in the monitors for personal computers, monitors for workstations, etc., the display screens are becoming higher definition, and therefore the deflection circuit of the monitor internal circuit, the power supply circuit, the video circuit, the control circuit, etc. are also made faster. Has been done.

As a result, from the monitor, unnecessary interference radio waves,
Radiation of electromagnetic waves and electric fields has become easier.

On the other hand, since the shadow mask of a cathode ray tube has been made higher in definition, it has become more susceptible to the influence of geomagnetism.

In addition, the monitor manufacturing countries are manufactured at low prices not only in Japan but also in Southeast Asia, and the price competition is becoming fiercer.

A conventional degaussing circuit in a cathode ray tube display will be described with reference to FIGS. 4 and 5.

In FIG. 5, the degaussing coil 1 is wound around the cathode ray tube 17.

In addition, in order to prevent unnecessary interference radio waves, electromagnetic waves, and electric field waves from radiating, the chassis structure is also realized by using the metal case 15 which covers the cathode ray tube.

Further, in order to prevent the interfering signals from the deflection circuit of the monitor internal circuit, the power supply circuit, the video circuit, the control circuit, etc. from flowing into the degaussing coil, they are suppressed and prevented by the filters L and C in FIG.

FIG. 4 is a circuit diagram for explaining the degaussing circuit.

The degaussing coil is generally connected through L and C of the noise removing filter and between the power source of the commercial power source 12 and the positive polarity thermistor 14.

For safety, the power switch 18 and the fuse 19 are connected from the rear side.

The operation of the degaussing circuit is as follows:
When 8 is closed, a degaussing current flows through the degaussing coil 1 via the positive polarity thermistor 14.

Immediately after the power switch 18 is closed, the positive polarity thermistor 14 remains in a cold state, so that the resistance is low and the maximum current can be passed through the degaussing coil. Also begins to generate heat, so the degaussing coil current gradually decreases.
In particular, since the commercial power source is an alternating power source, this degaussing coil current can perform degaussing action because it operates in a damping vibration while changing positively, negatively, and positively and negatively in accordance with the change of the commercial frequency.

[0016]

[Problems to be Solved by the Invention]

(1) The above-described conventional technique has a problem that the cost is high because a metal case that covers the cathode ray tube is used, and that if the metal case is removed, the interference radiation from the degaussing coil itself cannot be suppressed.

(2) Further, since the metal case for covering the cathode ray tube is used, there is a drawback that the weight becomes heavy.

The object of the present invention is to solve the above problems (1) and (2).
It is an object of the present invention to provide a degaussing coil in a cathode ray tube display that solves the above problem.

[0019]

In order to solve the above problems, in the present invention, the function of the degaussing coil is improved by shielding the degaussing coil in the cathode ray tube display with a conductive tape or a conductive gutter. While maintaining this, the interference radiation from the degaussing coil itself was suppressed and the weight was reduced.

[0020]

[Function] A non-magnetic conductive tape is attached to the exterior of the degaussing coil.
Shielding using a conductive gutter or the like prevents a decrease in magnetic resistance, and maintains an electrostatic shield effect, thereby suppressing interference radiation from the degaussing coil itself.

Needless to say, even if the shield used for a conductive tape, a conductive gutter, or the like is not thick, it is more preferable as long as it has an electrostatic shielding effect and the workability during assembly is good.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3.

In FIG. 1, 1 is a winding portion of the degaussing coil,
2 is a conductive tape, 4 is a lead extraction portion of the degaussing coil 1, 3
Is a connector connecting portion for connecting the lead lead-out portion 4 to a circuit.

FIG. 2 shows the degaussing coil 1 and the conductive tape 2 of FIG.
It is explanatory drawing which drew the part of in detail.

Insulation tape 5 for preventing dielectric breakdown when the conductive tape 2 is wound on the degaussing coil 1.
It is drawn in the state covered in advance.

The insulating tape 5 can be realized by cutting a tube into pieces or by winding the tape in layers.

When the conductive tape 2 is wound, if the tapes are overlapped with each other, a short circuit occurs. Therefore, if the tapes are overlapped with the insulator 7, the influence can be reduced.

A grounding circuit 6 is provided for electrically grounding the conductive tape 2 to electrostatically shield it.

FIG. 3 illustrates a state in which the degaussing coil 1 is embedded in a conductive gutter.

By accommodating the degaussing coil 1 in a state in which the insulating tape 5 is wrapped in the conductive gutter 8, the same effect as in FIG. 2 can be expected.

A part of the conductive gutter 8 is cut and bent to provide a grounding terminal portion 9, and a screw mounting hole 10 is provided in the terminal portion.

[0032]

According to the present invention, it is needless to say that the interference radiation from the degaussing coil itself can be suppressed without using the metal case covering the degaussing coil and the cathode ray tube, and further, the metal case covering the cathode ray tube is not used. The display monitor can be made lighter.

Further, since the degaussing coil is directly electrostatically shielded, not only is the structure extremely simple, but the outer shape can be freely fitted even in the complicated wiring state of the degaussing coil, and the production is possible. In addition to excellent properties, the degaussing coil itself can be manufactured in a state where the degaussing coil itself has an electrostatic shielding effect in advance, so that the production cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a degaussing coil of the present invention.

FIG. 2 is an explanatory diagram of an embodiment of the degaussing coil of the present invention.

FIG. 3 is an explanatory diagram of an application example of one embodiment of the degaussing coil of the present invention.

FIG. 4 is an explanatory diagram of a degaussing circuit in the related art.

FIG. 5 is an explanatory view of mounting a degaussing coil in a conventional technique.

[Explanation of symbols]

1 ... Degaussing coil, 2 ... Conductive tape, 8 ... Conductive gutter, 1
4 ... Positive polarity thermistor, 15 ... Metal case.

Claims (2)

[Claims] 1. In the degaussing circuit of a cathode ray tube display, the entire coil is made electrically conductive in order to prevent unnecessary interference radio waves, electromagnetic waves, and electric field waves from the deflection circuit, power supply circuit, video circuit, control circuit, etc. from radiating. A degaussing coil characterized by winding and covering tape. 2. The degaussing coil according to claim 1, wherein the entire coil is fitted in a gutter made of a conductive material.