KR20050023601A - Electron Gun For CRT - Google Patents

Abstract

PURPOSE: An electron gun is provided to prevent a deterioration of an alignment caused due to the magnetic piece arranged at the bottom surface of a shield cup during assembly of electron gun. CONSTITUTION: An electron gun comprises a plurality of in-line type cathodes and a plurality of electrodes for radiating electron beams; a shield cup(16) opposed to at least one of the electrodes; and a magnetic piece(16a) formed on the surface of the shield cup opposed to the electrode. A shield cup opposed electrode(20) has a surface where a magnetic piece opposed portion is opened.

Description

Electron Gun for Cathode Ray Tube {Electron Gun For CRT}

The present invention relates to an electron gun for a cathode ray tube, and more particularly, to preventing alignment deterioration due to a shield disk formed on the bottom of a shielding shield bottom.

Referring to Fig. 1, a conventional color cathode ray tube structure will be briefly described. The color cathode ray tube includes a panel (1) mounted on the front surface, a fluorescent surface (1a) coated with phosphors of red (R), green (G), and blue (B) on the inner surface of the panel, and a fluorescent surface behind the fluorescent surface. A shadow mask 2 having a color sorting function of an incident electron beam is provided. And a funnel (3) coupled to the rear of the panel and installed to maintain the interior in a vacuum state, and an electron gun (5) mounted inside the tubular neck portion that is retracted to the rear of the funnel to emit an electron beam (4) And a deflection yoke 6 which surrounds the outer side of the funnel and is arranged to deflect the electron beam in a horizontal or vertical direction.

2 is a schematic view for explaining the structure of the electron gun for the cathode ray tube. As shown, a cathode 8 for generating an electron beam, a first electrode 9 disposed at a predetermined distance from the cathode, a second electrode 10 disposed at a predetermined distance from the first electrode, The third electrode 11, the fourth electrode 12, the focusing electrodes 13 and 14 and the anode 15 disposed to be separated by a predetermined distance from the fourth electrode, and attached to the ends of the anode to shield the leakage magnetic field. It consists of a shield cup 16 for the BSC 17 for supporting the electron gun. Each of the electrodes is fixed by the bead glass 18 to maintain a constant interval, the electron gun is inserted into the neck glass 7 constituting the neck portion of the funnel, the neck glass stem for applying a voltage to the electron gun from the outside (19) It is fused with a part and mounted in a cathode ray tube.

On the other hand, the electron beam emitted from the electron gun reproduces the image on the entire screen screen by the self-convergence type deflection yoke, which is a non-uniform magnetic field.

Fig. 3 is a schematic diagram showing the distribution of the deflection magnetic field due to the deflection yoke and the shape of the electron beam at a predetermined position on the screen. As shown in FIG. 3, the horizontal deflection magnetic field of the deflection yoke forms a pin-cushion (HB) type magnetic field, and the vertical deflection magnetic field forms a barrel (VB) type magnetic field. Thus, the three electron beams arranged inline are matched to the phosphors of the fluorescent film without a separate dynamic convergence.

However, as shown in FIG. 3, the magnetic field formed by the deflection yoke has a higher magnetic field density toward the periphery in the horizontal direction than the center portion, so that each of the three electron beams arranged inline causes distortion in the cross section according to the magnitude of the magnetic field density. 4 is a diagram for explaining the influence of a deflection magnetic field on each of three electron beams. That is, as shown in FIG. 4, the red (R) and blue (B) electron beams are forced in the direction of the arrow by the pincushion magnetic field of the deflection yoke. This causes halo and blooming.

FIG. 5 is a diagram for describing a halo phenomenon and a blooming phenomenon occurring for each of three electron beams in the periphery of the screen. As shown in FIG. 5, a halo phenomenon occurs in the inner electron beams 21 ′ and 22 of the three electron beams, and a blooming phenomenon occurs in the outer electron beams 21, 22 ′. These halo and blooming phenomena are a major cause of deterioration of focusing characteristics. This phenomenon becomes more severe toward the periphery of the screen, which also causes a decrease in the resolution of the image formed by excitation of the fluorescent film.

As a conventional technique for solving such a problem, various techniques for reducing the coma aberration of the electron gun have been introduced. For example, Japanese Patent Application Laid-Open No. 4-52586 shows that the upper and lower flat electrodes on the bottom of the shield cup of the inline electron gun narrow the paths of the three electron beams in parallel with the in-line arrangement direction of the electron beam. It is installed to face up. In addition, according to Japanese Patent Application Laid-Open No. 51-61766, a quadrupole lens is formed between some electrodes of an electrode constituting the electron gun, and the intensity of the electrostatic quadrupole lens is varied according to the deflection signal in response to the deflection of the electron beam, thereby displaying on the entire screen The homogenization of was aimed at. Further, according to Japanese Patent Application Laid-Open No. 51-64368, an astigmatism lens is provided in the region of the electrode forming the preliminary focusing lens so as to form a uniform electron beam cross section on all fluorescent surfaces, or in Japanese Patent Application Laid-Open No. 10-116569. As disclosed, the electron beam passing holes of the first and second electrodes of the electron gun are formed to have different aspect ratios, thereby preventing distortion of the electron beam landing on the central portion and the peripheral portion of the fluorescent surface.

As a second attempt to solve the above problem, a technique of installing a magnetic piece on an electrode or neck portion has been proposed. As a representative example of such a magnetic piece attachment technique, Japanese Patent Laid-Open No. 10-116570 discloses that a magnetic piece is provided on a part of an electrode constituting the electron gun and a magnetic field generating device is mounted on the outer wall of the neck to deflect therefrom. Disclosed is a configuration for correcting deflection aberration of an electron beam by generating a magnetic field synchronous with a signal to excite the magnetic piece. In addition, according to Korean Patent Publication No. 2001-91314, four circular magnetic bodies are formed on the rear surface of the shield cup so as to be located between the centers of the electron beams on both sides of the electron gun emitting three electron beams and the center hole. It was configured to correct the.

However, as described above, reducing the coma aberration may modify the shape of the electron beam through hole in order to preserve the deflection aberration of the electron beam due to the deflection magnetic field, or may vary the magnification of the electron lens in synchronization with a signal applied to the deflection yoke. It is made through such a process, there was a disadvantage that the manufacturing and control of the electron beam is difficult.

The magnetic piece attachment technique as described above may have some effect in preserving deflection aberration of the R and B beams. However, when the magnetic piece is attached to the electrode surface, the magnetic surface is attached to the electrode surface and the shield cup. Alignment cannot be maintained in the process of attaching the backs to each other. Since the alignment is not maintained as above, there is a problem in that the equipotential lines of the vertical magnetic field are rapidly changed to distort the path of the beam considerably.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem in the related art, and an object of the present invention is to provide an electron gun having excellent alignment retention between an electrode and a shield cup in a process of manufacturing an electron gun having a magnetic piece attached structure.

Another object of the present invention is to provide an electron gun for a cathode ray tube that can prevent alignment deterioration caused by a magnetic piece and effectively maintain deflection aberration of an electron beam generated by a deflection magnetic field.

Technical means of the present invention for achieving the above object is a plurality of in-line cathode and a plurality of electrodes for emitting an electron beam, and a shield cup formed opposite to at least one electrode of the plurality of electrodes An electron gun for a cathode ray tube comprising: a magnetic piece formed on an electrode opposing surface of the shield cup, wherein a portion opposing the magnetic piece is opened on an opposing surface of the shield cup opposing electrode.

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

FIG. 6 is a first embodiment according to the present invention, and includes a plurality of in-line cathodes for emitting an electron beam, a plurality of electrodes, and a shield cup formed to face at least one of the plurality of electrodes. (A) shows the shape of the electrode 20 formed on the shield cup opposing surface of the electron gun, (b) shows the shield cup shape attached to the magnetic piece 16a projected on the electrode. . As shown, the opposing surface of the shield cup opposing electrode is formed such that a portion facing the magnetic piece attached to the bottom of the shield cup is opened. That is, as shown in (b) of FIG. 6, the magnetic pieces are positioned inside the electrode facing surface opening 20a. This is to prevent the deterioration of the alignment between the shield cup and the electrode by forming a magnetic piece formed on the bottom surface of the shield cup at a predetermined length in the electron beam emission direction when the electron gun is assembled. At this time, the opening of the electrode surface formed on the shield cup opposing surface is preferably formed as an open hole in the form of two opposite straight lines and two opposing arcs cross-connected, as shown in Figure 6 (a), such a shape The opening hole of the track is called a track opening hole.

On the other hand, the magnetic piece can be experimentally determined that the amount of correction of the electron beam distortion is different depending on the position attached to the bottom of the shield cup.

7 (a) and 7 (b) show values of correction amounts of R (red) and B (blue) electron beam distortions depending on the positions of the magnetic pieces attached to the bottom of the shield cup. As shown, the magnetic piece may be attached to a predetermined position with respect to the center hole G among the three electron beam through hole holes R, G, and B. The point at which the correction amount of the electron beam distortion caused by the magnetic piece is maximized is the point “C” as in the correction amount value according to the position (b) of FIG. 7. The point “C” is a point spaced apart by about 4 mm in the horizontal direction and about 3.5 mm in the vertical direction from the three electron beam through hole center holes. As such, the magnetic pieces should be attached at least a certain distance from the center of the electron beam through hole at the bottom of the shield cup to have maximum efficiency in correcting the electron beam distortion.

In the first embodiment of the present invention, the magnetic piece formed on the bottom surface of the shield cup is located inside the opening of the electrode surface formed in the track shape, so that the alignment between the shield cup and the electrode can be maintained. However, since such a position is not the maximum position capable of preserving the deflection aberration as shown in FIG. 7, the effect of the correction of the electron beam distortion does not bring much effect. As a result, there is a problem that the dispersion of the quality to preserve the deflection aberration occurs. Therefore, in order to obtain the maximum effect of maintaining alignment between the shield cup and the electrode and at the same time maintaining deflection aberration, it is preferable to change the shape of the shield cup opposing electrode as follows.

8 is a view illustrating another shape of an electrode formed on a shield cup opposing surface according to Embodiment 2 of the present invention. As shown in the drawing, the electrode is formed with an elongated portion 20a 'having a groove having a predetermined length in the track-shaped opening surface. The cover part formed as described above satisfies the optimum position of the magnetic piece described above with reference to FIG. 7 to maintain alignment between the shield cup and the electrode, and to optimally maintain deflection aberration. In addition, the escape portion affects the main lens mirror generated during the operation of the electron gun.

9 shows the shape of the lens mirror and the traveling electron beam according to the electrode shape of Example 1 and the electrode shape of Example 2 according to the present invention. As shown, the track-shaped electrode of FIG. 9 (a) has a small opening vertical width (V), so that the density of the lens is high, so that when the alignment is not maintained accurately during assembly of the electron gun, the beam distortion 4a that proceeds appears severely. In the electrode of FIG. 9 (b) having the skin portion, the vertical width of the opening is larger than that of the track-shaped electrode, so that the lens mirror d becomes larger and has the same alignment as the electrode of the first embodiment. 4b) does not appear severely.

In this case, as shown in FIG. 10, when the maximum vertical width of the vertical openings of the electrodes is Vmax and the minimum vertical width is Vmin, the ratio of the minimum vertical width to the maximum vertical width of the electrode is 0.42 <Vmin. It is preferable to satisfy the range of / Vmax <0.79. In addition, the ratio of the maximum vertical width (Vmax) to the maximum horizontal width (Hmax) of the opening hole of the electrode preferably satisfies the range of 0.45 <Vmax / Hmax <0.84. This takes into account the ease of the assembly process in assembling the electron gun and the path of the electron beam generated at the cathode.

FIG. 11 is a view illustrating another opening shape of the shield cup facing surface electrode according to the third embodiment of the present invention. As shown, the electrode may have various opening shapes. However, even at this time, it is preferable that the magnetic piece is formed in the opening so as not to contact the magnetic piece attached to the shield cup.

As such, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof. Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the foregoing description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

As described above, the present invention has the effect of preventing the alignment deterioration caused by the magnetic piece installed on the bottom of the shield cup when assembling the electron gun by forming the shield cup of the electron gun and the opening of the electrode facing the shield cup in a track shape. have.

In addition, there is an effect that can effectively preserve the electron beam distortion that may be caused by alignment degradation by forming a coating in the opening of the track-like electrode.

1 is a view showing a typical color cathode ray tube.

Figure 2 is a schematic view showing an electron gun for a conventional cathode ray tube.

3 is a view showing a visualized deflection magnetic field for deflecting a conventional electron beam;

4 is a view showing a state in which an electron beam is deflected by a conventional pin cushion magnetic field.

5 is a view showing an electron beam shape shown in a conventional cathode ray tube screen.

6 is a view showing the shape of the electrode formed on the shield cup opposing surface of the electron gun and the shield cup shape attached to the magnetic pieces projected on the electrode according to the first embodiment of the present invention.

Figure 7 is a second embodiment of the present invention, showing another shape of the electrode formed on the shield cup opposing surface of the electron gun.

FIG. 8 is a diagram showing values of correction amounts of R (red) and B (blue) electron beam distortions depending on the position of the magnetic pieces attached to the bottom of the shield cup. FIG.

9 is a view showing a state of the electron beam and the lens mirror according to the electrode shape of Example 1 and the electrode shape of Example 2 according to the present invention.

10 is a view showing the size of the open hole of the electrode formed on the shield cup opposing surface of the electron gun according to the present invention.

FIG. 11 is a third embodiment of the present invention, showing another shape of the shield cup facing surface electrode of the electron gun; FIG.

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

1: panel 2: shadow mask

3: funnel 4: electron beam

5: electron gun 6: deflection yoke

7: Neck part 8: cathode

9: first electrode 10: second electrode

11: third electrode 12: fourth electrode

13, 14: focusing electrode 15: anode

16: Shield Cup 17: BSC

18: Bead glass 19: Stem pin

20: Shield Cup Opposing Electrode of the Present Invention

Claims (5)

In the electron gun for cathode ray tube comprising a plurality of in-line cathode and a plurality of electrodes for emitting an electron beam, and a shield cup formed to face at least one of the plurality of electrodes, Further comprising a magnetic piece formed on the electrode opposing surface of the shield cup, Electron gun for cathode ray tube, characterized in that the portion facing the magnetic piece is opened on the opposite surface of the shield cup counter electrode. The method of claim 1, Electron gun for cathode ray tube, characterized in that the track-shaped opening hole is formed on the opposite surface of the shield cup counter electrode. The method of claim 2, Electron gun for cathode ray tube, characterized in that the opening is formed on the opposite surface of the shield cup opposing electrode formed with an escape portion. The method of claim 3, wherein The open hole on the opposite surface of the shield cup counter electrode has a maximum vertical width of Vmax, and a minimum vertical width of Vmin, and a minimum vertical width of 0.42 <Vmin /. An electron gun for cathode ray tubes, characterized by satisfying a range of Vmax <0.79. The method of claim 3, wherein The open hole on the opposite surface of the shield cup counter electrode has a maximum vertical width of Vmax of the open hole open hole vertical width, and a maximum horizontal width of Hmax, with a maximum vertical width relative to the maximum horizontal width Hmax of the electrode. An electron gun for cathode ray tubes, wherein the ratio of the width Vmax satisfies the range of 0.45 < Vmax / Hmax < 0.84.