KR20030072932A - Crt - Google Patents

Abstract

PURPOSE: A color cathode ray tube is provided to shield electromagnetic waves leaked from the monitor and cathode ray tube, while achieving improved color purity characteristics. CONSTITUTION: A color cathode ray tube comprises a panel having an inner surface on which a phosphor screen is mounted; a funnel attached to the rear of the panel and constituted by a body portion, a cone portion and a neck portion; an electron gun including a cathode for emitting three electron beams and a plurality of electrodes spaced apart from the cathode; a deflection yoke for deflecting the electron beams emitted from the electron gun; a convergence purity magnet(13) for controlling the electron beams in such a manner that the electron beams are concentrated on a single point; an external conductive film(14) formed at the body portion of the funnel; and a conductive electromagnetic wave shielding tape(20) arranged in the neck portion of the funnel.

Description

Color Cathode Ray Tube {CRT}

The present invention relates to a color cathode ray tube, and more particularly, to a conductive electromagnetic wave shielding tape which is attached to a cathode ray tube to shield electromagnetic waves harmful to a human body and at the same time improves color purity characteristics.

1 is a view showing a schematic configuration of a general color cathode ray tube, the front glass of the panel 1 and the rear glass of the funnel 2 composed of the body portion, the cone portion, and the neck portion are combined, and the inner surface of the panel 1 A fluorescent surface 4 which serves as a light emitting function of light, an electron gun 9 which is a source of the electron beam 6 which emits the fluorescent surface 4, and a shadow mask 3 which selects colors to emit light of a predetermined phosphor; Frame assembly (7) for supporting the shadow mask (3), and the reinforcing band (11) wrapped around the funnel (2) to ensure safety.

Convergence Purity Magnets (CPM) are attached to the neck portion of the funnel 2 to adjust the concentration of the three electron beams 6 from the electron gun 9 at one point, and inside the cathode ray tube An inner shield 12 is incorporated to reduce the distortion of the path of the electron beam 6 by the system, and an outer shield is provided outside the cathode ray tube to improve electromagnetic shielding and geomagnetic margin.

In a television or monitor employing the cathode ray tube configured as described above, a circuit for driving the cathode ray tube is combined with the cathode ray tube to express an image desired by the viewer.

The operating principle of the color cathode ray tube disclosed in FIG. 1 is as follows.

In the electron gun 9 embedded in the neck portion of the funnel 2, the electron beam 6 strikes the fluorescent surface formed on the inner surface of the panel 1 by the anode voltage applied to the cathode ray tube. In this case, the electron beam 6 ) Is deflected up and down and left and right by the deflection yoke 5 before reaching the fluorescent surface to form a screen.

When the electron beam 6 emits a fluorescent surface to represent an image, an inner shield inside the cathode ray tube in order to allow the electron beam 6 to be scanned at the correct position of the panel 1 by the geomagnetic field without distortion of the path. (12) is built in and the outside is equipped with an outer shield.

Then, in a circuit for driving the cathode ray tube, an appropriate voltage and current are applied to the electron gun 9 and the deflection yoke 5 to express an image necessary for the cathode ray tube.

When driving the cathode ray tube as described above, electromagnetic waves harmful to the human body are generated in the electron gun, the deflection yoke, and the circuit. The electromagnetic wave is electrically connected to the conductive film formed on the outside of the funnel and shielded. It is also shielded by the out shield.

In recent years, as the problem of electromagnetic waves adversely affecting the human body is a trend that is increasingly tightened, and from this point of view, it is necessary not only to satisfy TCO and EMI standards, which are the standards on allowable electromagnetic waves, but also need to be improved.

Table 1 below shows the specific regulations regarding electromagnetic waves of TCO and EMC.

TABLE 1

Frequency band 5 ㎐ to 2 ㎑ 2 ㎑ to 400 ㎑ 30 MHz to 1 GHz Measuring distance TCO Standard 10 V / m or less 1.0 V / m or less 30 cm EMC standard (FCC Rart15) 40㏈㎶ or less 10 m

In Table 1, shielding measures against electromagnetic waves of 2 kHz to 400 kHz (VLF band) in the TCO standard and electromagnetic waves of 30 MHz or more in the frequency range of the EMC standard are very difficult and can be considered very important problems.

Moreover, recent monitor trends have led to the development of a visible nipple model and the need to reduce the volume of the monitor in order to reduce the space occupied by the monitor, thus eliminating the external shield (0ut Shield) between the monitor cover and the color cathode ray tube (CRT). You need to get rid of it.

However, if the external shield is removed, the amount of electromagnetic leakage harmful to the human body increases, and it becomes sensitive to changes in the geomagnetic field, thereby changing the path of the electron beam emitted from the electron gun of the cathode ray tube, thereby degrading color purity characteristics. Done.

Accordingly, an object of the present invention is to solve the conventional problems, and to provide a cathode ray tube capable of shielding electromagnetic waves harmful to a human body and at the same time preventing distortion of the movement path of the electron beam by a geomagnetic field. .

1 is a cross-sectional view of a typical cathode ray tube.

2 is a view showing a cathode ray tube in which an outer conductive film is formed on a body portion of a funnel;

3 is a view showing a cathode ray tube wound with a conventional general cotton tape.

Figure 4 shows a cathode ray tube with a conductive electromagnetic wave shielding tape according to the present invention.

5 is a detailed view of portion A of FIG. 4;

Figure 6 is a view comparing the change amount of the electron beam of the cathode ray tube according to the present invention and the cathode ray tube according to the prior art.

7 is a view showing another embodiment according to the present invention.

8 is a view showing the shape and structure of the conductive electromagnetic wave shielding tape of FIG.

*** Explanation of symbols for the main parts of the drawing ***

1: panel 2: funnel

2-2: body portion 2-2: cone portion

2-3: Neck 5: Deflection yoke

9: electron gun

13: Convergence Purity Magnets (CPM)

14: outer conductive film 20: conductive electromagnetic shielding tape

The present invention for achieving the object as described above, a panel provided with a fluorescent surface on the inner side, a fusion funnel consisting of a body portion, a cone portion and a neck portion, fused to the rear of the panel, R (Red), G (Green), B (Blue) An electron gun including a cathode generating three-color electron beams and a plurality of electrodes sequentially arranged at regular intervals from the cathode, a deflection yoke for deflecting the electron beam emitted from the electron gun, and one point of the electron beam In the cathode ray tube including a Convergence Purity Magnets (CPM) to adjust to focus on, and an outer conductive film formed on the body portion of the funnel, the neck of the funnel is provided with a conductive electromagnetic shielding tape having a predetermined length It features.

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

The present invention wraps the conductive electromagnetic wave shielding tape on the outer circumferential surface of the funnel, thereby shielding electromagnetic waves harmful to the human body and preventing distortion of the movement path of the electron beam by the geomagnetic field.

The present invention, as shown in Figure 4, the panel having a fluorescent surface, the body portion enclosed with the panel, the funnel consisting of a cone portion and the neck portion, the electron gun enclosed in the neck portion of the funnel, the entire funnel outer peripheral surface except the cone portion and neck portion of the funnel An outer conductive film applied continuously to the deflection yoke (5) mounted on the cone portion of the funnel and having a deflection coil, a convergence purity magnets (CPM) 13 mounted on the neck portion of the funnel and the deflection of the outer peripheral surface of the funnel; Conductive electromagnetic shielding tape 20 attached to the mounting position of the yoke and CPM (Convergence Purity Magnets) (13).

The conductive electromagnetic wave shielding tape 20 is attached to the position where the deflection yoke horizontal coil starts to deflect at the end of the neck portion of the funnel.

In Figure 4, the conductive electromagnetic wave shielding tape 20 according to the present invention has a total length (L) of the cathode ray tube and the direction length (THL) of the conductive electromagnetic wave shielding tape surrounding the outer peripheral surface of the funnel is 0 <THL <0.25 * The length (D) of the outer circumference of the funnel neck portion and the length (TLV) perpendicular to the tube axis of the conductive electromagnetic shielding tape covering the outer circumferential surface of the funnel, satisfying the range value of L and the range of TLV ≥ D (2 * π * R) It is characterized by satisfying the value.

The direction length (THL) of the conductive electromagnetic wave shielding tape surrounding the outer circumferential surface of the funnel is preferably 25% or less of the total cathode ray tube length, and the conductive electromagnetic wave blocking tape surrounding the length (D) of the outer diameter of the funnel neck portion and the outer circumferential surface of the funnel. The length (TLV) perpendicular to the tube axis is approximately 100mm.

Because the distance from the neck end of the funnel of a general cathode ray tube to the point where the deflection yoke's horizontal deflection coil starts to deflect is about 20% of the total length of the cathode ray tube, distort the deflection of the horizontal coil of the deflection yoke or discharge In order to prevent the phenomena, the direction length THL of the conductive electromagnetic wave shielding tape surrounding the outer circumferential surface of the funnel is preferably 25% or less of the total length of the cathode ray tube.

In addition, since the diameter of the neck portion of the funnel is 29.1 mm and the circumference of the neck portion is about 92 mm, the length (TLV) perpendicular to the tube axis of the conductive electromagnetic wave shielding tape surrounding the outer circumferential surface of the funnel is 92 which can completely wind the neck portion of the funnel. About -100 mm is suitable.

FIG. 5 is a detailed view of part A of FIG. 4, wherein the conductive electromagnetic shielding tape is attached to the neck portion of the funnel and the conductive electromagnetic shielding tape is secured for electrical connection (grounding) with the circuit. It is shown.

As shown in Figure 5, the starting point of the conductive electromagnetic shielding tape is 20mm or less at the end of the neck, the distance from the starting point to the mounting position of the Convergence Purity Magnets (CPM) should be at least 3mm.

Since the distance between the cathode and the first electrode where the electron beam of the general electron gun is generated is 20 mm or less, the starting point of the conductive electromagnetic shielding tape in FIG. 5 is preferably 20 mm or less at the end of the neck portion.

In addition, the distance from the start point of the conductive electromagnetic shielding tape to the CPM (Convergence Purity Magnets) mounting position is at least 3mm to secure a space for the conductive electromagnetic shielding tape to be energized by electrical connection (grounding) with the circuit. The ideal must be.

In Figure 3, the neck tape of the conventional funnel is a means for preventing the flow of the deflection yoke and Convergence Purity Magnets (CPM) by simply increasing the friction force in the state in which the deflection yoke and Convergence Purity Magnets (CPM) is fastened without conductivity It was.

However, the conductive electromagnetic wave shielding tape 20 according to the present invention as shown in FIG. 4 is made of a conductive material in which nickel and copper are plated on both sides of a polyester fiber, and the adhesive is also configured to be conductive.

The conductive electromagnetic shielding tape is a material of nickel and copper components that can have conductivity, high permeability, and low coercive force at the same time, the component ratio of the conductive shielding tape is nickel (Ni) 10 to 60% by weight, copper (Cu) 40 to 90% by weight is suitable and the surface resistance is preferably 1 kPa or less.

The operation of the cathode ray tube according to the present invention configured as described above will be described.

The cathode ray tube according to the present invention, like the conventional cathode ray tube, accelerates the electron beam by applying a high pressure to the fluorescent surface formed on the inner surface of the panel while simultaneously deflecting the electron beam emitted from the electron gun embedded in the neck portion of the funnel at the deflection coil. The fluorescent surface emits light by the energy to express an image.

In this case, electromagnetic waves are generated in the deflection yoke, the electron gun, and the circuit board. The harmful electromagnetic waves generated as described above are shielded by a conductive electromagnetic shielding tape having a resistance value per unit area of 1 Ω or less covering the outer circumferential surface of the funnel of the present invention. do.

That is, since the conductive electromagnetic shielding tape is located up to the lower region of the deflection coil, a part of the harmful electromagnetic waves generated from the deflection coil is located on the lower conductive coil shielding electromagnetic shielding tape according to the present invention. Although not shown in the drawing, the electromagnetic wave is electrically connected to a circuit (circuit board) by a device designed separately from the back of the CPM (Convergence Purity Magnets), thereby removing harmful electromagnetic waves.

In addition, since the conductive electromagnetic shielding tape surrounds the entire neck portion of the funnel in which the electron gun is enclosed, harmful electromagnetic waves generated from the electron gun are also focused and shielded by the conductive electromagnetic shielding tape according to the present invention.

Table 2 below compares the electromagnetic wave shielding effect of the cathode ray tube according to the prior art and the cathode ray tube according to the present invention.

TABLE 2

Conventional cathode ray tube Cathode ray tube according to the present invention TCO standard (2 kHz to 400 kHz) 1.0 V / m 0.9 V / m 0.7 V / m EMC standard (30 MHz to 1 GHz) 40 Hz 38㏈㎶ 34㏈㎶

As shown in Table 2, it can be seen that the cathode ray tube according to the present invention is more effective in shielding electromagnetic waves than the cathode ray tube according to the prior art.

As described in the operation of the cathode ray tube according to the prior art, the electron beam emitted from the electron gun of the cathode ray tube is deflected in the deflection yoke and landed on the phosphor at the correct position of the fluorescent surface to form an image. The earth's magnetic field generated by the axis of the book affects the path of the electron beam, resulting in a decrease in color purity (purity) characteristics.

In order to solve the above problems, conventionally, an inner shield and an outer shield were installed to reduce the influence from the geomagnetic field. However, the above method is limited and generally reduces the geomagnetic field effect by about 50%. It just works.

However, the conductive electromagnetic shielding tape according to the present invention is plated or deposited with a polyester fiber of about 30% by weight of nickel (Ni) and about 70% by weight of copper, the high permeability and low coerciveness of the nickel (Ni) By shielding the influence of the geomagnetic field invested into the electron gun through the neck of the funnel from the initial stage of the electron beam of the electron gun.

Therefore, it is possible to further reduce the influence of the geomagnetic field to reduce the change of the path of movement of the electron beam, thereby improving the color purity characteristics.

Such an effect can be seen in FIG. 6 comparing the change amount of the electron beam of the cathode ray tube according to the present invention and the cathode ray tube according to the prior art.

7 shows another embodiment according to the present invention.

In FIG. 7, the conductive electromagnetic wave shielding tape 20 surrounds the outer circumferential surface of the funnel from the position of the electrode adjacent to the cathode of the electron gun to the outer conductive film (B).

Since the application range of the conductive electromagnetic wave shielding tape 20 extends to the position where the outer conductive film 14 of the body portion of the funnel is located, the shielding effect of the electromagnetic waves may be further improved.

However, in the above case, in order to prevent electrical conduction between the deflection coil and the conductive electromagnetic wave shielding tape, the insulating layer A must be formed on the surface where the deflection yoke and the conductive electromagnetic wave shielding tape are in contact with each other.

In another embodiment according to the present invention, the same effect can be obtained by depositing nickel and copper directly on the neck portion of the funnel, rather than attaching the tape to the neck portion of the funnel.

Therefore, according to the present invention, it is possible to shield electromagnetic waves harmful to the human body generated by the electron gun and the deflection coil by electrically connecting the electromagnetic wave shielding tape having a resistance of 1 kΩ or less provided in the neck portion of the funnel. Since the electron beam emitted from the electron gun through the negative can reduce the distortion of the electron beam path under the influence of the geomagnetic field, there is an effect that can prevent the degradation of the color purity characteristics.

Claims (8)

A panel provided with a fluorescent surface on the inner side, and a cathode which is fused to the rear of the panel and generates electron beams of three colors of funnel, R (Red), G (Green) and B (Blue), which are composed of a body part, a cone part and a neck part. Electron gun including a plurality of electrodes sequentially arranged at a constant distance from the cathode, deflection yoke for deflecting the electron beam emitted from the electron gun, Convergence Purity Magnets (CPM) to adjust the concentration of the electron beam to a point In the cathode ray tube comprising an outer conductive film formed on the body portion of the funnel, Cathode ray tube, characterized in that the neck portion of the funnel is provided with a conductive electromagnetic shielding tape of a predetermined length. The method of claim 1, The starting point of the conductive electromagnetic shielding tape is a cathode ray tube, characterized in that within 20mm from the end of the neck portion of the funnel. The method of claim 1, The end point of the conductive electromagnetic wave shielding tape is a cathode ray tube, characterized in that up to the position where the deflection coil starts. The method of claim 1, The end point of the conductive electromagnetic wave shielding tape is a cathode ray tube, characterized in that to the outer conductive film formed on the outer peripheral surface of the funnel. The method of claim 4, wherein And the conductive electromagnetic wave shielding tape has no conductivity in a region corresponding to the deflection coil. The method of claim 2, And a distance from a starting point of the conductive electromagnetic shielding tape to the CPM (convergence purity magnets) mounting position is greater than 3 mm. The method of claim 1, A cathode ray tube, characterized in that the resistance value of the conductive electromagnetic wave shielding tape is 1 Ω or less. The method of claim 1, The conductive electromagnetic wave shielding tape contains Ni (nickel) and Cu (copper) components, the Ni (nickel) is 10 to 60% by weight, the Cu (copper) satisfies 40 to 90% by weight Cathode ray tube.