KR100266564B1 - Electro magnetic shielding equipment of deflection yoke for cathode ray tube - Google Patents

Abstract

PURPOSE: An apparatus for shielding an electromagnetic wave in a deflection yoke of a cathode ray tube is provided to prevent a damage due to an electromagnetic wave by shielding an electric field and a magnetic field generated from a deflection yoke. CONSTITUTION: An apparatus for shielding an electromagnetic wave in a deflection yoke of a cathode ray tube comprises a shielding cap for shielding a magnetic field and an electric field generated from a deflection yoke. The shielding cap covers the deflection yoke. The shielding cap comprises an electric field shielding layer(22) and a magnetic field shielding layer(23). The electric field shielding layer(22) and the magnetic field shielding layer(23) are surrounded by a cover(21). A multitude of heat-sink hole(24) is formed on a whole face of the shielding cap.

Description

Electromagnetic shielding device of cathode ray tube deflection yoke

1 is a perspective view of a shielding cap used in a conventional electromagnetic shielding device.

2 is a cross-sectional view of a cathode ray tube showing a state where a conventional electromagnetic shielding device is mounted.

Figure 3 is an exploded perspective view of a cathode ray tube equipped with the present invention.

Figure 4 is an external perspective view showing an embodiment by the device of the present invention.

5 is a longitudinal sectional view of FIG.

6 is a partially cutaway perspective view of the shielding cap according to the present invention.

Figure 7 is a perspective view of the main incision showing the molding state of the earth fin according to the present invention.

8 is a longitudinal sectional view of the molded earth fin of FIG.

9 is a cross-sectional view of a cathode ray tube showing a state in which the apparatus of the present invention is mounted.

* Explanation of symbols for the main parts of the drawings

11 cathode ray tube 12 deflection yoke

20: shielding cap 22: electric shield cap

23: magnetic shield cap 24: heat sink

The present invention relates to an electromagnetic shielding device of the deflection yoke between the cathode ray lines, and in particular to improve the shielding of the leakage electric field and the magnetic field generated in the deflection yoke portion more effectively to shield the electromagnetic wave from the cathode ray tube deflection yoke portion. Relates to a device.

In general, the cathode ray tube is a glass bulb consisting of a panel, a funnel and a neck portion, and the inside of the tube is made of high vacuum. An electron gun for generating an electron beam is accommodated inside the neck portion located behind the cathode ray tube, and a magnetic field is generated on the outer circumferential surface of the funnel and the neck so as to deflect the electron beam injected from the electron gun to a predetermined position on the light surface of the panel. Deflection Yoke is installed to make this happen.

However, such a deflection yoke is composed of a horizontal deflection coil portion and a vertical deflection coil portion, and a large amount of electromagnetic waves are generated and leaked to the outside from the horizontal deflection coil portion to which a high voltage is applied during operation of the cathode ray tube. As the electric field and the electric field is a factor that damages the surrounding electronics or the human body.

In this case, an electric field is generated while the high voltage generated by the flyback transformer (FBT) is applied to the horizontal deflection coil.

(E is the strength of the electric field, V is the applied voltage, and d is the distance).

Therefore, in the deflection coil, an electric field is generated in the tangential direction (orthogonal to the outer circumferential surface of the lead wire) of the deflection coil wire in proportion to the applied voltage, thereby leaking to the surroundings and the outside.

In addition, magnetic current is generated clockwise around the vertical deflection coil part when current flows in the advancing (entry) direction of the right screw according to the right screw law of ampere.

(H is the strength of the magnetic field, N is the number of turns of the coil, I is the current flowing through the deflection coil, r is the radius of the coil portion), and thus the magnetic field is generated in proportion to the current applied to the deflection coil and leaks to the surroundings and to the outside. Will be.

As described above, the electric field and the magnetic field are severely affected by the human body and the surroundings, and thus are restricted by the EMI (Electronic Magnetic Interference) standard, which is the subject of electromagnetic interference regulation in the world. It is done.

As described above, the conventional apparatus for shielding the electromagnetic wave generated in the cathode ray tube deflection yoke portion is a deflection yoke provided in the neck portion 1a of the cathode ray tube 1 as shown in FIGS. 1 and 2. 2) is configured by installing a shielding cap (7) for shielding. Heat dissipation grooves 7a are formed on both sides of the rear end of the shielding cap 7, and the shielding cap 7 is formed by using a separate fixing piece 8 so as to be caught by the upper outer peripheral surface of the deflection yoke 2. It is fixed to (1).

At this time, the shielding cap (7) is made of a non-conductive non-conductive powder core (core) component, the magnetic field (Magntic Fild) of the electromagnetic waves generated in the deflection yoke (2) can be shielded, but the electric field ( Shielding of Electric Fild is impossible, and shielding case 5 is installed inside the cabinet 3 and the back cover 4 of the product as shielding means of the electric field to shield the electric field.

However, the electromagnetic wave shielding device of the conventional cathode ray tube deflection yoke as described above has a defect that the electric field shielding is not made in the deflection yoke, and the shielding cap blocks heat generated from the deflection yoke, thereby degrading the performance of the cathode ray tube. And leakage of some magnetic fields generated from the deflection yoke to the heat dissipation groove formed in the shielding cap, and the cost increases due to the installation of a shield case for shielding the electric field which is not made of the shielding cap. there was.

The main object of the present invention devised to solve such a problem is to improve the reliability of the product by completely shielding the electric and magnetic fields of electromagnetic waves generated in the deflection yoke.

Another object of the present invention is to simplify the configuration of the device to reduce cost and improve productivity.

In order to achieve the object of the present invention, in order to shield the electric field and magnetic field generated in the deflection yoke is provided with a shielding cap surrounding the deflection yoke, the shielding cap shields the electric field and the magnetic field Electromagnetic shielding device between the cathode ray deflection yoke portion characterized in that it comprises a magnetic shield layer.

The field shielding layer and the magnetic shielding layer of the shielding cap are surrounded by an outer shell formed on the outer surface, and a plurality of heat dissipation holes are perforated over the entire shielding cap.

The outer shell is 3 mm or more, and a flame retardant resin is used.

The field shielding layer is 34-40 μm and is a nonmagnetic material. The magnetic shielding layer is 40 μm and is a nonmagnetic, nonconductive material.

The heat radiating hole has a diameter of 6-8 mm.

The shielding cap is provided with a hood for fastening to the deflection yoke.

Hereinafter, the present invention as described above will be described in more detail with reference to the accompanying drawings.

3 is an exploded perspective view of a cathode ray tube equipped with the present invention device, Figure 4 is an external perspective view showing an embodiment according to the present invention, Figure 5 is a longitudinal cross-sectional view of Figure 4, Figure 6 is for the present invention Partly cutaway perspective view of the shielding cap, FIG. 7 is a major cutaway perspective view showing the molding state of the earth pin according to the present invention, FIG. 8 is a longitudinal sectional view of the molded earth pin of FIG. 7, and FIG. Of the cathode ray tube shown.

As shown in the drawing, in the electromagnetic wave shielding device of the cathode ray tube deflection yoke unit, the deflection yoke 12 installed on the neck portion 13 of the cathode ray tube 11 is provided with a shielding cap 20 at the outer periphery thereof. It is made up.

The shielding cap 20 is formed by sequentially stacking the outer shell 21, the electric field shielding layer 22, and the magnetic shielding layer 23, and covers a plurality of shielding caps 20 over the entire surface of the shielding cap 20. The heat dissipation hole 24 is formed.

The outer shell 21 is a hollow tapered shape, the material is formed of a flame-retardant resin material, the electric field shield layer 22 is a coating material coated with a non-magnetic material having high electrical conductivity and high magnetic permeability, the magnetic shielding Layer 23 is a paint made of a high magnetic permeability nonmagnetic, nonconductive material.

The thickness t1 of the shell 21 is formed in a large amount of 0.3 mm or more in consideration of strength, and the thickness t2 of the field shielding layer 22 is constant at about 34-40 μm in consideration of the optimality of the field shielding. The thickness t3 of the magnetic shielding layer 23 is reduced by the oxidation of the electric field shielding layer 22 applied to the inside in consideration of the optimality of the magnetic shielding in combination with oxygen in the air. In order to prevent the coating, apply a constant amount of 40㎛ or more.

The heat dissipation hole 24 is formed so that the diameter (2R) is 6.8mm in order to maximize the shielding effect of the electric field and magnetic field generated in the deflection yoke 12, the interval (L) between the heat dissipation holes 24 is 4mm or more It is preferable to form.

The rear end of the shielding cap 20 is formed of a conductive material as a grounding means for grounding the electric field generated by the deflection yoke 12 and is in contact with the field shielding layer 22 and the magnetic shielding layer 23. The spin 30 and the earth wire 40 connected to this earth pin 30 are used.

The earth pin 30 is a rivet 28 through which the shielding cap 20 is inserted between the field shielding layer 22 and the magnetic shielding layer 23 and penetrates the fixing hole 27 and the fixing hole 31. It is fixed to the shielding cap 20, the earth wire 32 is connected to the nap solder hole 32 to the earth pin (30). In addition, the ground of the earth pin 30 is connected to the earth wire 16 of the cathode ray tube 11, which is in contact with the coated graphite film 17 of the cathode ray tube 11, the funnel portion 14, and the earth pin 30. The earth wire 32 to be grounded has an equipotential.

On the other hand, a predetermined number of hooks 25 are integrally formed with the sheath 21 at the outer periphery of the front end portion of the shielding cap 20, and a through hole 26 is formed at the center of the rear end portion of the through hole 26. The neck portion 13 of the cathode ray tube 11 is inserted, and the hook 25 is fitted to the outer periphery of the deflection yoke 12 so that the shielding cap 20 surrounds the deflection yoke 12. Will be installed.

In the figure, reference numeral 15 denotes a reinforcing band, and 15a shows a fixing lug.

The operation and effects of the present invention configured as described above will be described.

When power is applied to the cathode ray tube 11, a voltage is applied to the horizontal coil portion and the vertical coil portion of the deflection yoke 12, and a current flows, so that the electron beam deflects, and a high voltage of tens of thousands of volts is applied. In the horizontal deflection coil portion, a large amount of electromagnetic waves containing a magnetic field and an electric field component are emitted.

As described above, the magnetic field component of the electromagnetic wave emitted from the deflection yoke 12 is shielded in the magnetic shielding layer 23 of the shielding cap 20, which has a high magnetic permeability of the magnetic shielding layer 23 and is nonmagnetic and specific. By trapping the leakage magnetic field generated by the properties of the material of the conductive material in the magnetic shielding layer 23 to block the radiation to the outside of the shielding cap 20, the permeability of the medium is high As the shielding effect increases. Since the magnetic shielding layer 23 is made of a nonmagnetic material, the magnetic field of the horizontal or vertical deflection coil is scattered so as not to affect the deflection action.

In addition, the plurality of heat dissipation holes 24 formed in the shielding cap 20 are perforated at appropriate sizes and intervals to completely shield the leakage magnetic field, as well as to disperse heat generated uniformly to the outside for heat dissipation effect. Will also be improved.

On the other hand, the electric field component of the electromagnetic wave emitted from the deflection yoke 12 is shielded in the field shielding layer 22 of the shielding cap 20, which is high in electrical conductivity and high magnetic permeability of the field shielding layer 22. When the leaking electric field is hit by the field shielding layer 22 due to the property of the material of the material, the leakage electric field is grounded through the earth fin 30 and the earth wire 40, and at this time, Since the earth wire 16 and the earth wire 40 of the earth pin 30 are grounded in the equipotential state, shielding of the leakage electric field is effectively performed. Since the material of the field shielding layer 22 is a nonmagnetic material having a high permeability, it blocks the external leakage of the magnetic field and the electric field, and does not affect the deflection action.

In addition, the heat radiating hole 24 is also shielded in the same manner as in the magnetic field shielding of the unnecessary radiation of the leaking electric field.

As described above, the electromagnetic wave shielding device of the deflection yoke between the cathode ray lines according to the present invention is formed in a deflection yoke by installing a shielding cap formed by stacking electric and magnetic shielding layers and forming a plurality of heat dissipation holes in the deflection yoke. Since it can completely shield the leakage electromagnetic waves, it prevents various harmful effects due to the unnecessary radiation of electromagnetic waves, which improves the reliability of the product, and reduces the cost and productivity by simplifying the configuration of the device. It is to be applicable to the electromagnetic shielding device of the deflection yoke in all image display devices.

Claims (7)

In order to shield the electric field and magnetic field generated in the deflection yoke 12, the shielding cap 20 surrounding the deflection yoke 12, the shielding cap 20 is an electric field shielding layer 22 for shielding the electric field And a magnetic shielding layer (23) for shielding a magnetic field. The field shielding layer 22 and the magnetic shielding layer 23 of the shielding cap 20 are surrounded by an outer shell 21 formed on the outer surface of the shielding cap 20, and a plurality of shielding caps 20 are provided throughout the shielding cap 20. Electromagnetic shielding device between the cathode ray deflection yoke portion, characterized in that perforated two heat radiation holes (24). 3. The electromagnetic shielding device of claim 2, wherein the outer shell (21) is 3 mm in length and is flame retardant. The electromagnetic shielding device of claim 1 or 2, wherein the field shielding layer (22) is 34-40 μm and is a nonmagnetic material. The electromagnetic shielding device of claim 1 or 2, wherein the magnetic shielding layer (23) is 40 µm or more and is a nonmagnetic, nonconductive material. 3. The electromagnetic shielding device of claim 2, wherein the heat dissipation hole (24) has a diameter (2R) of 6.8 mm. The electromagnetic shielding device according to claim 1 or 2, wherein the shielding cap (20) is provided with a hook (25) for fastening to the deflection yoke (12).