KR20000033554A - Cathode ray tube - Google Patents

Abstract

PURPOSE: A cathode ray tube is provided whose structure is improved to improve the convergence characteristics of an electron beam landed on a fluorescent film by varying the shape of a fusion splicing between a funnel and a neck part. CONSTITUTION: A cathode ray tube is provided to improve the convergence characteristics of an electron beam(30). The cathode ray tube comprises a panel, a funnel faced with the panel, and an electron gun which can be inserted into a neck part(25) spliced in fusion with the funnel. The outer circumference of the fusion-spliced part between the funnel and the neck part is formed convex in order for a space part of the inside of the fusion-spliced part to be able to be extended.

Description

Cathode ray tube

The present invention relates to a cathode ray tube, and more particularly, to a cathode ray tube in which a shape of a fusion portion of a funnel and a neck portion into which an electron gun is introduced is changed.

Typically, the cathode ray tube is formed by the electron beam emitted from the electron gun is deflected by the deflection yoke and landing on each phosphor of the fluorescent film. In order to form a clearer image, it is necessary first of all to accurately land the electron beam on each phosphor of the fluorescent film.

The electron gun 10 that emits such an electron beam includes a heater 11, a cathode 12, a control electrode G1, 13, and a screen, called an emission portion emitting electrons, as shown in FIG. 1. It comprises a tripolar portion of the electrodes (G2, 14). The first, second, and third focus electrodes G3, G4, G5, 15 to 17, which are sequentially installed corresponding to the screen electrode 14 to form a prefocus lens, and the third focus electrode 17 And a final acceleration electrode G6 installed correspondingly to the main lens part.

The electron gun 10 is focused and accelerated by an electron lens in which an electron beam emitted from the cathode 12 is formed between each electrode as a predetermined potential is applied to each electrode. Subsequently, the electron beam passes through the shadow mask to impinge on each phosphor of the phosphor film formed on the inner surface of the panel.

In order to accurately land the electron beam on the phosphor, accurate convergence must be achieved during focusing and acceleration. Convergence refers to the concentration of red, green, and blue electron beams at a point in an electron beam through hole of a shadow mask. The three-color electron beam is simultaneously deflected by the deflection magnetic field generated by the deflection yoke and scanned to the edge of the screen. When the electron beam passing through the electron beam passing hole is not concentrated at one point, a miss landing phenomenon occurs.

Also, even in the case of cathode ray tube where the convergence adjustment is completed so that the electron beam is concentrated at one point of the electron beam passing hole of the shadow mask, it is formed on both sides of the electrode as a certain time passes after the preheating and screen adjustment processes in other assembly processes. A convergence drift phenomenon occurs in which the red and blue electron beams are horizontally moved a predetermined distance.

In the conventional electron gun 10, when a predetermined power is applied to the heater 11, thermal drift occurs due to thermal expansion of the control electrode 13 and the screen electrode 14, and accumulates on the inner wall of the neck portion when passing through the main lens unit. The positive (+) charge causes the red and blue electron beams to be pulled toward the neck, resulting in a change in convergence.

Therefore, in order to exclude such a phenomenon, the formation of the electron gun is variously modified so that the electron gun can be less affected by the distance between the inner wall of the neck portion and the electron beam passing holes of the electrodes 17 and 18 which emit red and blue electron beams. 10), but the results are still poor.

The present invention has been made to solve the above problems, to provide a cathode ray tube with an improved structure to improve the convergence characteristics of the electron beam landing on the fluorescent film by changing the shape of the fusion portion of the funnel and the neck portion. There is this.

1 is a cross-sectional view schematically showing a conventional electron gun,

Figure 2 is a cross-sectional view showing a cathode ray tube according to an embodiment of the present invention,

3 is an enlarged cross-sectional view of a neck portion into which the electron gun of FIG. 3 is inserted;

<Simple explanation of the code | symbol about the main part of drawing>

10,30. Electron gun 11,31. Heater

12,32. Cathowood 13,33. Control electrode

14,34. Screen Electrode 15,35. First focus electrode

16,36. Second focus electrode 17,37. Third focus electrode

18,38. Final acceleration electrode 20. Cathode ray tube

21.Panel 22. Funnel

25. Neck part 300. Flare part

Cathode ray tube according to an aspect of the present invention to achieve the above object,

A cathode ray tube comprising a panel having a fluorescent film formed on an inner surface thereof, a funnel encapsulating the panel, and an electron gun including a control electrode, a screen electrode, a focus electrode, and an accelerating electrode that can be inserted into a neck portion fused with the funnel.

The fusion portion of the funnel and the neck portion is characterized in that the outer circumferential surface thereof is formed convex so that the inner space is expandable.

In addition, the fusion portion may be fusion-bonded by the first block portion formed to have a predetermined curvature from the end of the funnel and the second block portion having the same curvature in the direction corresponding to the first block portion from the end of the neck portion. Here, the center portion of the interval between the focus electrode and the acceleration electrode of the electron gun is characterized in that it is provided so as to be located in the fusion unit.

Hereinafter, the cathode ray tube of the present invention will be described in detail with reference to the accompanying drawings.

2 shows a cathode ray tube 20 according to an embodiment of the present invention.

Referring to the drawings, the cathode ray tube 20 is provided with a panel 21 having a fluorescent film 21a having a predetermined pattern formed on an inner surface thereof, and a funnel 22 sealed to an end of the panel 21. In addition, a shadow mask 23 having a myriad of electron beam through holes formed therein and a frame 24 to which the shadow mask 23 is fixed are provided at a predetermined distance from the panel 21. An electron gun 30 is introduced into the neck portion 25 of the funnel 22, and a deflection yoke 27 is provided in the cone portion 26 of the funnel 22.

As shown in FIG. 3, the electron gun 30 includes a heater 31 and a cathode 32 that emit electrons, and control electrodes G1 and 33 that emit electrons and control electron emission amounts by external signals. ) And a three-pole portion consisting of screen electrodes G2, 34.

The first, second and third focus electrodes G3, G4, G5, and 35 to 37, which are sequentially installed to correspond to the screen electrode 34, form a prefocus lens, and the third focus electrode ( 37 and a final acceleration electrode 38 installed corresponding to the main lens unit.

At this time, the cathode 32 is formed so that the three inline (Inline) is arranged to emit a red, green, blue electron beam. In addition, each of the electrodes is formed such that the electron beam passing holes through which the three-color electron beams respectively pass are arranged in an inline shape, or that three electron beams can pass simultaneously.

On the other hand, at the point where the third focus electrode 37 and the final acceleration electrode 38 forming the main lens portion are provided, the funnel 22 and the neck portion 25 according to the features of the present invention are formed. That is, the funnel 22 is fused so that its end portion is sealable with the neck portion 25. This fusion site is where the main lens section of the electron gun 30 is located.

Here, the end portion of the funnel 22 and the fusion portion of the neck portion 25 are molded to have a flare shape in which the outer circumferential surface is convex so that the space portion therein is enlarged. That is, an end portion of the funnel 22 forms a first block portion 310 convex outwardly from the end thereof, and an end portion of the neck portion 25 that is in surface contact with the first block portion 310 and is fused. Forms a second block portion 32 to achieve the same curvature in the opposite direction.

Thus, the first and second block portions 310 and 320 having the curvatures formed in the corresponding directions are thermally fused. In this case, the electron gun 30 must be drawn in such a way that the center of the gap between the G5 electrode 37 and the G6 electrode 38 is located at the heat fusion unit. In this case, the red and blue electron beam passing holes formed at both sides of the electrodes 37 and 38 of the main lens portion are relatively far from the fusion portions of the funnel 22 and the neck portion 25.

In the cathode ray tube 20 configured as described above, the electron beam emitted from the electron gun 30 is selectively deflected by the deflection yoke 27 to excite the phosphor of the fluorescent film 21a to form an image.

In the process of forming the image, adjustment of the convergence drift of the tricolor electron beam emitted from the electron gun 30 is essential. Although the electron beam emitted from the electron gun 30 is attracted to the positive (+) charge accumulated along the inner wall of the neck portion 25 of the funnel 22, the drift phenomenon will occur even if trying to improve the convergence characteristics. According to the feature, the funnel 22 and the neck portion 25 form the flare 300 of which the outer peripheral surface is convex on the same line as the center of the interval between the electrodes 38 and 39 constituting the main lens portion.

As a result, the distance between the red and blue electron beam passing holes of the main lens portion, the funnel 22, and the neck portion 25 becomes relatively far, and the influence of the positive (+) charge is greatly reduced, thereby reducing the convergence drift.

As described above, in the cathode ray tube of the present invention, by changing the shape of the fusion portion of the funnel and the neck portion, it is possible to reduce the phenomenon that the three-color electron beam is mislanded on the phosphor of the fluorescent film, thereby improving the convergence characteristics. As a result, the screen resolution of the cathode ray tube can be increased.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (3)

A cathode ray tube comprising a panel having a fluorescent film formed on an inner surface thereof, a funnel encapsulating the panel, and an electron gun including a control electrode, a screen electrode, a focus electrode, and an accelerating electrode that can be inserted into a neck portion fused with the funnel. A cathode ray tube, characterized in that the outer peripheral surface of the fusion portion of the funnel and the neck portion is formed to be convex so that the inner space is enlarged. The method of claim 1, Wherein the fusion portion is the first block portion formed to have a predetermined curvature from the end of the funnel, and the second block portion having the same curvature in the direction corresponding to the first block portion from the end of the neck portion is fused in surface contact with each other Cathode ray tube characterized in that. The method of claim 2, And a center portion of the gap between the focus electrode and the acceleration electrode of the electron gun is positioned in the fusion unit.