KR200347062Y1 - Electron gun for color CRT - Google Patents

Abstract

The disclosed subject matter relates to an electron gun for color cathode ray tubes to prevent creeping discharges occurring between any electrode of the electron gun and the bead glass or neck portion.

In order to achieve this purpose, the present invention continuously connects the shield wire contact portion of the bead glass in joining the shield wire to the arbitrary electrode while wrapping the outside of the bead glass in order to reduce the potential difference between the arbitrary electrode and the bead glass or the neck. It is configured to have a convex curvature, characterized in that the adhesion to the shield wire is improved.

Description

Electron gun for color cathode ray tube {Electron gun for color CRT}

The present invention relates to an electron gun for a color cathode ray tube, and more particularly, to prevent creeping discharge generated between an arbitrary electrode of the electron gun and a bead glass or neck portion.

In general, color cathode ray tubes are the most widely used display devices for observation of oscilloscopes, radars, etc., including television receivers.

In the color cathode ray tube, since the three-color electron beam emitted from the electron gun strikes the fluorescent film inside the screen and displays the color, an electron gun capable of achieving a stable electron beam convergence is required.

For this purpose, a cathode in which hot electrons are radiated, and a plurality of electrodes for accelerating at high speed by making the hot electrons into thin electron beams and focusing on the fluorescent film inside the screen are arranged in line along the direction of the electron beam. Line electron guns are mainly applied.

A general color cathode ray tube incorporating such an inline electron gun is shown in FIG. 1.

As shown in the drawing, a panel 1 forming a screen and a funnel-shaped funnel 2 fused to the rear end of the panel 1 form a vacuum outer container, and a diameter of the funnel 2 having a small end, that is, a neck ( 3), the electron gun 5 which radiates the electron beam 4 is enclosed.

On the inner side of the panel 1, a fluorescent film 6 constituting a pixel is formed, and a shadow mask 7 is formed to be separated from the fluorescent film 6 by a predetermined distance to perform color discrimination function. A deflection yoke 8 for generating a pincushion type horizontal deflection magnetic field and a barrel type vertical deflection magnetic field is mounted on the outer side near the neck portion 3 side.

In this state, the electron beam 4 emitted from the electron gun 5 is deflected to a desired portion of the screen by the vertical and horizontal deflection magnetic fields of the deflection yoke 8, and passes through the shadow mask 7 in a state where color selection is made. The fluorescent film 6 hits and implements an image.

As such, the electron beam 4 smoothly hits the fluorescent film 6 to realize an image, and a constant speed and focusing force are required, which is made possible by the electron gun 5.

That is, the electron gun 5 includes a cathode 9 for radiating hot electrons in a predetermined temperature range, a control electrode 10 for accelerating and concentrating hot electrons emitted from the cathode 9, and an acceleration electrode ( 11), the focusing electrode 12, the anode 13 which pulls out the electron beam 4, and the shield cup 14 which shields the unnecessary magnetic field by the deflection yoke 8, the cathode 9 and each The electrodes 10, 11, 12, and 13 are embedded in the bead glass 15, which is an electrical insulator, and are sequentially arranged and spaced apart by a predetermined distance. The hot electrons radiated from the cathode 9 are controlled by the control electrode 10 and accelerated. The electron beam 4 is accelerated and focused while passing through the electrode 11 and the focusing electrode 12 to be smoothly landed on the fluorescent film 6.

At this time, in order to focus the electron beam 4, the voltage applied to each of the electrodes 10, 11, 12, and 13 is formed to form an electrostatic lens by the difference in voltage, and the electron beam 4 forms the electrostatic lens. By passing through, focusing and final acceleration are performed, and landings in the fluorescent film 6 can be constructed.

Looking at the voltage applied to each electrode, the control electrode 10 is grounded, a high voltage of more than 400 ~ 1200V to the acceleration electrode 11, 20000V applied to the anode 13, the anode 13 to the focusing electrode 12 ) An intermediate voltage of 20 to 34% of the applied voltage is applied.

As is well known, the potential difference is related to the discharge phenomenon, and as shown in Equation 1 below, the voltage difference has a relation proportional to the potential difference, so that the discharge is started between the focusing electrode 12 and the anode 13 having the largest voltage difference among the electrodes. Phenomenon occurs.

[Equation 1]

E = V / d

E: potential difference or electric field, V: voltage, d: interval

Most of the discharges in the electron gun 5 are in the form of Creeping Discharge. As shown in FIG. 3, the stray electrons of the anode beam current are close to the anode 3 inner wall or bead glass 15. ) And secondary electrons are generated. At this time, since charges accumulate on the surface, the potential gradually increases than before the collision.

The increased potential affects the lower electrodes 10 and 11 to induce field emission, and the field emission generates another secondary electron to increase the surface potential of the bead glass 15 again. It will continue to work.

This increased potential eventually generates a discharge in the lower electrode direction, which causes a serious obstacle in the driving circuit.

Figure 4 shows the potential distribution for each step in a graph, it can be seen that the potential gradually increases over time.

Therefore, it is preferable that the potential increase caused by the voltage difference due to the formation of the electrostatic lens between the focusing electrode 12 and the anode 13 is not transferred to the lower electrode direction. A shield wire 16 welded to and configured on the focusing electrode 12 is provided.

That is, the shield wire 16 is for suppressing the potential rise in the lower electrode direction. Since the shield wire 16 has the same potential distribution in the installation section of the shield wire 16, the lower electrode is disposed from the shield wire 16 installation position as shown in FIG. The surface potential to be lowered to prevent creeping discharge.

Here, in the bead glass according to the prior art, as the electrode is embedded and fixed in the lower portion as shown in Fig. 6a, when performing the process of embedding and fixing each electrode structure in the bead glass, the upper portion of the bead glass to hold the beads without flow To configure.

Therefore, when welding and fixing the shield wire for improving the withstand voltage characteristic of the electron gun to the focusing electrode while wrapping the bead glass, the shield wire is incompletely contacted with the upper portion of the bead glass as shown in FIG. 6B.

This is because the upper shape of the bead glass is flat, even though the shield wire is pulled and welded, the adhesion between the two members is reduced by the upper shape of the bead glass.

As such, in the state where the shield wire and the bead glass are incompletely contacted, the potential distribution developed at the anode side cannot be effectively blocked, so the process of increasing the glass surface potential is repeated, resulting in a discharge phenomenon due to the potential difference between the glass surface potential and the lower electrode. There is a problem that causes damage to the cathode or serious failure of the drive circuit.

Therefore, the present invention has been proposed in view of this point, and improves the adhesion between the shield wire and the bead glass to prevent the increase in potential caused by the voltage difference between the focusing electrode and the anode to prevent the transition to the lower electrode electron gun for color cathode ray tube The purpose is to provide.

1 is a configuration diagram of a general color cathode ray tube,

2 is a configuration diagram of a general inline electron gun,

3 is a surface discharge pattern diagram in the neck portion,

4 is a graph showing a change in potential distribution in each step of FIG. 3;

5 is a change diagram of the potential distribution of each part with and without shield wire,

Figure 6a is a conventional bead glass figure,

6B is a shield wire bonding state diagram when the FIG. 6A is applied.

Figure 7a is a bead glass shape according to the present invention,

FIG. 7B is a shield wire bonding state diagram when the FIG. 7A is applied; FIG.

8 is another exemplary view of the present invention.

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

3: neck 12: focusing electrode

15 ': Beaded glass 15a': Beaded glass contact surface

16: shield wire 16a: spring

The electron gun for the color cathode ray tube according to the present invention for achieving the above object is enclosed in the neck of the funnel, and a plurality of electrodes, such as a control electrode, an accelerating electrode, a focusing electrode, and an anode, are embedded in the bead glass and are sequentially arranged. In the mold gun:

(1) At least one of the plurality of electrodes,

A shielding member which reduces the potential difference with the bead glass or the neck is bonded to surround the outside of the bead glass;

(2) the shield member contact portion of the bead glass,

It is configured to have a convex curvature continuously in cross section is characterized in that the adhesion to the shield member is enhanced.

Optionally, the shielding member has an elastic member between the contact portion with the bead glass and the electrode joint portion.

In this case, the adhesion is excellent at the contact surface between the shield wire serving as the shield member and the bead glass serving as the fixing member.

As a result, the rise of the potential developed from the upper portion of the shield wire installation position is shielded without being transferred to the lower side thereof, so that the potential difference between each electrode and the bead glass or the neck becomes small, so that creeping discharge does not occur.

And, there may be a plurality of embodiments of the present invention, hereinafter will be described in detail with respect to the most preferred embodiment.

Through this preferred embodiment it is possible to better understand the objects, features and advantages of the present invention.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the electron gun for color cathode ray tube according to the present invention in detail.

In addition, in drawing used for description, about the component same as FIG. 1 thru | or 6, the same code | symbol may be attached | subjected, and the overlapping description may be abbreviate | omitted.

Figure 7a is a bead glass shape according to the present invention, Figure 7b is a shield wire bonding state diagram when the Figure 7a is applied, Figure 8 is another embodiment of the present invention.

As shown, the electron gun for the color cathode ray tube according to the present embodiment has the focusing electrode 12 and the bead glass so that the rise of the potential due to the voltage difference between the anode 13 and the focusing electrode 12 does not continuously transition to the lower side. 15 ') or the shield wire 16, which reduces the potential difference between the neck 3, to the focusing electrode 12 in the state in which the bead glass 15' is wrapped, the shield wire 16 and the bead glass 15 '. The shape of the bead glass 15 'for improving the adhesion of the "

That is, the shape of the shield wire contact surface 15a 'of the bead glass is changed, and this portion 15a' has a curvature of a shape having a high center in cross section and gradually decreasing toward both sides, that is, a convex curvature continuously. Except for this portion 15a ', the rest is formed in a planar shape with the same height of the center and both sides as in the conventional structure.

In general, the bead glass 15 'is configured to flatten the upper portion of the bead glass 15' in order to hold the bead glass 15 'without flow when performing the process of embedding and fixing each electrode, but the specific area, that is, the shield wire contact surface In the case of (15a '), it is configured as described above to improve the adhesiveness of both members.

At this time, it is obvious that the shield wire contact surface 15a 'of the bead glass should be formed to be equal to or larger than the width of the shield wire 16 in contact therewith.

The electron gun for the color cathode ray tube according to the present invention made as described above operates as follows.

As is well known, in-line electron guns form an electrostatic lens with a difference in the voltage applied to the anode 13 and the focusing electrode 12, so that it is inevitably separated by the voltage difference between the anode 13 and the focusing electrode 12. Electrons are generated and charges are accumulated in the bead glass 15 'or the neck 3 by the escape electrons, so that the potential is raised, thereby affecting the lower electrode to cause creeping discharge.

The discharge phenomenon is more likely to occur as the potential difference between the electrodes 10, 11, 12 and the bead glass 15 or the neck 3 increases, so that the above-mentioned discharge phenomenon does not occur. 12) and the potential difference between bead glass (15 ') or neck (3).

Therefore, it is preferable to prevent the increase of the potential caused by the voltage difference between the anode 13 and the focusing electrode 12 from being transferred to the lower electrode side. In this aspect, the shield wire 16 and the bead glass 15 ', which are shielding members, are prevented. ) Is important.

That is, when the adhesion between the shield wire 16 and the bead glass 15 'is improved, the potential of the shield wire 16 is lowered relative to the installation position of the shield wire 16, so that the electrodes 10 and 11 and the bead glass positioned at the bottom thereof are reduced. The potential difference between the 15 'and the neck 3 is not large, and thus no discharge phenomenon occurs.

Therefore, the present invention is to change the shape of the shield wire contact surface (15a ') of the bead glass in order to improve the adhesion between the shield wire 16 and the bead glass (15'), the area is high in the cross-sectional view and both sides It is configured to have a curvature in the form of gradually lowering, that is, convex continuously.

In this state, when the shield wire 16 is wrapped around the bead glass 15 'and pulled to weld to the focusing electrode 12, the shape of the shield wire contact surface 15a' of the bead glass has a convex curvature continuously. The outer edges of the shield wire 16 and the bead glass 15 'may be closely adhered to each other without gaps. Then, when both ends of the shield wire 16 are welded to the focusing electrode 12, the shield wire 16 and the bead glass 15' ) Can be maintained as it is.

In addition, as shown in FIG. 8, when an elastic member such as a coil spring 16a is formed on one side of the shield wire 16, adhesion to the bead glass 15 ′ may be further increased.

On the other hand, as a comparative example, unlike the prior art, that is, the high potential is not effectively blocked by the gap with the shield wire as the upper surface of the bead glass is formed flat, the present invention provides a shape of the shield wire contact portion of the bead glass Since it is configured to have a continuous convex curvature, the bead glass and the shield wire can be closely contacted without any gap.

In this result, according to the present invention, the high potential is effectively blocked to prevent creepage discharge at the lower electrode on the basis of the shield wire installation interval, thereby fundamentally preventing damage to the cathode or failure of the driving circuit. .

In addition, although specific embodiments of the present invention have been described and illustrated above, it is obvious that the present invention may be variously modified and implemented by those skilled in the art.

Such modified embodiments should not be individually understood from the technical spirit or the prospect of the present invention, and such modified embodiments shall fall within the appended utility model registration claims of the present invention.

It is clear from the above description that according to the present invention, since the shield wire and the bead glass are closely contacted with each other without any gap, the high potential is cut off to prevent creeping discharge of the lower electrode, thereby not affecting the cathode or the driving circuit, thereby ensuring reliability. There is an effect that can be done.

Claims (2)

In an inline electron gun encapsulated in a neck of a funnel, in which a plurality of electrodes, such as a control electrode, an acceleration electrode, a focusing electrode, and an anode, are embedded in a bead glass and sequentially arranged: (1) At least one of the plurality of electrodes, A shielding member is bonded to surround the outside of the bead glass; (2) the shield member contact portion of the bead glass, An electron gun for a color cathode ray tube, which is configured to have a curvature that is continuously convex in cross section and has improved adhesion to the shielding member. The method of claim 1, The shield member, An electron gun for a color cathode ray tube, characterized by having an elastic member between a contact portion with the bead glass and the electrode joining portion.