KR940011644B1 - Electron gun using advanced shield cup for color cathode-ray tube - Google Patents

Abstract

The electron gun provides the fine color pictures by improving the electron beam focusing characteristic. The electron gun comprises a first transit hole (22) formed in a shield cup (20); a first electrode (23) welded at a recess (21) of the shield cup; a second electrode (24) applied lower voltage than the one of the first electrode; a second transit hole (25) formed at a retainer (26) curved in the form of circular arc and welded to the recess (21).

Description

Electron gun for cathode ray tube with improved shield cup

1 is a cross-sectional view of main parts of a cathode ray tube employing a conventional shield cup,

FIG. 2 schematically shows a raster pattern formed on the fluorescent surface of the conventional cathode ray tube shown in FIG.

3 is a schematic view for explaining the operation of the magnetic field controller employed in the shield cup of FIG.

4 (a) is a schematic view showing a cathode ray tube according to a first embodiment of the present invention, 4 (b) is a perspective view showing a shield cup shown in FIG. 4 (a),

5 is a schematic view for explaining the operation of the shield cup according to the first embodiment,

FIG. 6 (a) schematically shows a cathode ray tube according to a second embodiment of the present invention, and FIG. 6 (b) is an exploded perspective view of the main portion of the shield cup shown in FIG. 6 (a),

FIG. 7 (a) schematically shows the cathode ray tube according to the third embodiment of the present invention, and FIG. 7 (b) is an exploded perspective view of the main portion of the shield cup shown in FIG. 7 (a).

* Explanation of symbols for main parts of the drawings

20: shield cup 21: recess

22: first through hole 25: second through hole

26: Retainer 26a, 26b: Sleeve

The present invention relates to an electron gun for a color cathode ray tube, and more particularly, a three-electron beam matching red, blue, and green raster patterns formed on a screen by effective control of a magnetic field on an electron beam, and passing through each electrode of the electron gun. The present invention relates to an electron gun for a color cathode ray tube whose structure has been improved so that a high quality image can be realized by converging.

Typically, the assembled electron gun is installed on the inner wall of the neck, one end of which is fixed at the stem portion and the other end of which is fixed by a bulb spacer of a shield cup arranged at the end of the assembled electron gun. As shown in FIG. 1, the bulb spacers 2 having one end fixed to the shield cup 1 are generally provided at equal intervals, and the other ends thereof are embedded in the internal graphite 4 inside the funnel 3. It is in close contact with each other, and a high voltage is applied to the electrode 5 of the electron gun. Accordingly, the shield cup 1 simultaneously maintains the assembled electron gun in the neck 6 and simultaneously applies a high voltage to the electrode 5.

On the other hand, each electron beam emitted from the inline type electron gun mounted on the neck portion 6 of the cathode ray tube is deflected by the deflection yoke and landed on the fluorescent surface to form respective raster patterns. The raster pattern appearing on the fluorescent surface is as shown in FIG. 2 by the nonuniform magnetic field generated by the deflection yoke, so that the raster pattern 7 caused by the central electron beam does not coincide with the raster pattern 8 caused by the side electron beam. Will not. This mismatch of raster patterns means that the unit images of red, green, and blue are shifted from each other as a result, and the quality of the image is extremely degraded.

In order to remedy this problem, a magnetic field controller 9 for controlling the horizontal and vertical deflection magnetic fields generated from the deflection yoke is fixed to the electrode 5 at the end of the electron gun, as shown in FIGS. 1 and 3. It is provided around the electron beam passing hole of the shield cup 1 which has been used. Accordingly, the horizontal portion edge of the magnetic field controller 9 weakens the vertical deflection magnetic field 10 distributed around both side electron beam through holes, and weakens the horizontal deflection magnetic field 11 distributed around the central beam through hole in the vertical portion. The two raster patterns 7 and 8 are matched.

As described above, the shield cup 1 supplies high pressure to one electrode of the assembled electron gun, and is provided with a bulb spacer 2 to hold the electron gun in the neck portion, and has a magnetic body called a low-level controller 9 therein. Is provided to adjust the amount of movement of the electron beam serves to correct the fine convergence around the screen.

However, since the magnetic field controller 9 is made of a plate-like material, it is difficult to handle when assembling, and thus it is difficult to accurately position the magnetic cup controller 2 at a predetermined position on the inner surface of the shield cup 1. Arranged and fixed, in particular, the controller 9 and the bulb spacer 2 are installed as separate parts, there is a problem in that the number of parts and the number of labor.

It is an object of the present invention to provide an electron gun for a cathode ray tube in which the above problems are solved, and more particularly, a cathode ray tube electron gun whose structure is simplified to simultaneously perform the role of a bulb spacer and a magnetic field controller in one component. To provide.

Yet another object of the present invention is to allow the three electron beams that have passed through the shield cup to converge at the fluorescent surface.

In order to achieve the above object, the present invention provides a plurality of electrodes having three electron beam through holes, a shield cup fixed to a final end of the electrode, a plate-shaped retainer coupled to the outer periphery of the shield cup, and the electrodes. In the electron gun for color cathode ray tube having a converging means for converging and accelerating the electron beam by one point of the screen and a field controller provided in the electron beam exit area to give a corrected magnetic field to the electron beam passing area, the retainer is in the middle of the body Three electron beam passing holes through which the electron beam passing through the shield cup is formed in a row, and both ends thereof are fixed to the shield cup.

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

FIG. 4 (a) is a cross sectional view of a main part employing an electron gun assembled to the neck portion 6 of the cathode ray tube, showing another first embodiment of the present invention, and FIG. 4 (b) is shown in FIG. 4 (a). A schematic perspective view of an illustrated shield cup.

Reference numeral 20 denotes a shield cup, and a recess 21 is formed with a first through hole 22 through which red, green, and blue 3 electron beams emitted from a cathode (not shown) can pass. Reference numeral 23 is a first electrode welded to the recess 21 of the shield cup 20 to which a high voltage is applied, and reference numeral 24 is a voltage higher than that applied to the first electrode 23. It is a second electrode to which a relatively low voltage is applied. Here, as a main part of the present invention, a retainer 26 having a second passage hole 25 through which the electron beam passing through the first passage hole 22 may pass is formed on the outer peripheral surface of the upper end of the shield cup 20. It is bent in an arc shape and its both ends are fixed by welding. At this time, the retainer 26 has a greater curvature than the middle portion in which both ends thereof have a second through hole 25 so as to be in close contact with the neck 6.

Meanwhile, the retainer 26 may be formed by extending the bulb spacer 2 shown in FIG. 1.

6 (a) shows a second embodiment according to the present invention. This is because the cylindrical sleeves 26a and 26b as shown in Fig. 6 (b) are respectively inserted into the two through holes in the second through holes 25 formed in the retainer 26 of the first embodiment. will be. At this time, since the retainer 26 is formed to be curved in an arc shape, the electron beam outlet side of the cylindrical sleeves 26a and 26b into which the both side through holes are inserted has an inclined surface 26 '. Therefore, the cylindrical sleeves 26a and 26b of the upper phase are arranged such that the major circumferential side thereof faces the retainer 26. 7 (a) schematically shows a third embodiment according to the present invention, and FIG. 7 (b) is a schematic perspective view of the retainer 26 shown in FIG. 7 (a). This is the bending of the retainer 26 in the second through hole 25 formed in the retainer 26 of the first embodiment such that the central through hole protrudes in the electron beam traveling direction at a predetermined height than the both through holes. At this time, the retainer 26 has a greater curvature than the middle portion where the second through hole 25 is formed so that the retainer 26 can be in close contact with the neck 6 as in the first embodiment.

Hereinafter, other effects will be described in the above embodiment.

First, in the first embodiment, referring to FIGS. 4 (a) and 4 (b), the retainer 26, which is bent at a predetermined curvature, has both ends in close contact with the wall of the neck 6 so that the electron gun can be opened. 6) Keep it in the center. The retainer 26, which is in close contact with the neck 6, contacts the embedded graphite (not shown) to apply a high voltage to the first electrode 23. In this case, the three electron beams focused by the first electrode 23 and the second electrode 24 pass through the first through hole 22 of the shield cup 20 and the second through hole 25 of the retainer 26. The raster pattern is formed by irradiating the fluorescence point.

On the other hand, the horizontal deflection magnetic field 11 and the vertical deflection magnetic field 10 by the deflection yoke (not shown) distributed around the second through hole 25 of the retainer 26 are retainers as shown in FIG. The raster pattern by the electron beam weakened by (26) and passing through the center through hole coincides with the raster pattern by the electron beam through the both through holes. Accordingly, the cathode cup tube gun according to the present invention according to the first embodiment serves as a bulb spacer for maintaining it at the center of the neck 6 and as a magnetic field controller for weakening the non-uniform magnetic field caused by the deflection yoke. By reducing the number of parts and the assembly labor is reduced. In the second embodiment, with reference to the sixth (a) and the sixth (b), the retainer 26, which is bent at a predetermined curvature similarly to the first embodiment, is in close contact with the wall of the neck 6 and the electron gun Is maintained at the center of the neck 6 and is in contact with the embedded graphite (not shown) to apply a high voltage to the first electrode 23. The three electron beams focused by the first electrode 23 and the second electrode 24 pass through the first and second through holes 22 and 25 of the shield cup 20 to irradiate the corresponding fluorescent points. On the other hand, the non-uniform magnetic field caused by the deflection yoke (not shown) distributed around the second through hole 25 of the retainer 26 is weakened by the retainer 26 as shown in FIG. The master pattern can be matched. In addition, the electron beam focused by the first and second electrodes 23 and 24 and passing through the first through hole 22 is inserted into both side through holes of the second through hole 25. It is focused more by 26b, because the electron beam is attracted to the major circumferential side of the sleeves 26, 26b. Therefore, the electron gun according to the present invention improves the focus characteristic of the electron beam, thereby enabling image display with high color purity.

Also in the third embodiment shown in FIGS. 7 (a) and 7 (b), the retainer 26 maintains the electron gun in the center of the neck 6 in the same manner as the first and second embodiments. It also effectively controls the nonuniform magnetic field caused by the deflection yoke to match the raster pattern. In the retainer 26, since the central through hole is formed to protrude more than the opposite through hole, both electron beams passing through the first through hole 22 are attracted to the protruding side surface 27 and connected. Therefore, the electron gun according to the third embodiment improves the focus characteristic of the electron beam, thereby enabling image display with high color purity.

As described above, the cathode ray tube electron gun according to the present invention is different from the conventional one having a plurality of bulb spacers and a separate magnetic controller, so that only one retainer can simultaneously perform the roles of the conventional bulb spacer and the magnetic controller. And the number of parts is reduced, assembly labor is reduced. In addition, the present invention is an effective invention to increase the product value on the product by enabling the image display with high color purity by improving the focus characteristic of the electron beam.

Claims (4)

Screens a plurality of electrodes having three electron beam through holes, a shield cup fixed to the end of the electrode, a piece-shaped retainer coupled to the outer periphery of the shield cup, and an electron beam focused and accelerated by the electrodes. In the electron gun for color cathode ray tube having a converging means for converging to one point of the field and a field controller provided in the electron beam exiting area to impart a corrected magnetic field to the electron beam passing area, the retainer 26 is a shield cup 20 in the middle of the body; Three electron beam passing holes 25 through which the electron beam passing through are formed in a row, and both ends thereof are fixed to the shield cup 20. 2. The electron gun for the color cathode ray tube according to claim 1, wherein the electron beam passing hole 25 of the retainer 26 is provided with a converging means for imparting an asymmetric magnetic field to the electron beam passing therethrough so as to be concentrated toward the central electron beam. . The method of claim 2, wherein the converging means is formed by bending the retainer 26 such that the central electron beam passing hole protrudes in the electron beam traveling direction at a predetermined height higher than both electron beam passing holes in the electron load passing hole 25. Electron gun for color cathode ray tube to be made. The electron gun for color cathode ray tube according to claim 2, wherein the converging means has cylindrical sleeves (26a) and (26b) respectively provided in both electron beam through holes in the electron beam through holes (25).