KR930000336Y1 - Electron gun of color picture tube - Google Patents

Abstract

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Description

Kalashnikov gun

1 is a cross-sectional view of a general color CRT.

2 is a schematic representation of a typical gun.

3A is a plan view of a third electrode of the electron gun of FIG. 2, and FIG. 3B is a cross sectional view of the third electrode and the fourth electrode of the electron gun of FIG.

Figure 4a is a plan view of a third electrode of the electron gun of the present invention, Figure 4b is a cross-sectional view of the third electrode and the fourth electrode portion of the electron gun of the present invention.

* Explanation of symbols for main parts of the drawings

1: Color water pipe 2: Panel

3: funnel 4: neck

5: electron gun 6: electron bill

7: shadow mask 8: fluorescent film

9: deflection yoke 10: sealing part

11: connection terminal 12: stem

13: cathode 14: first electrode

15: second electrode 16: third electrode

17: fourth electrode

a, a ', 4, 4', c, c ': electron beam through hole

The present invention relates to an electron gun of a color CRT. In particular, the electrostatic lens formed by the voltage difference applied to the third electrode and the fourth electrode is extended to prevent deterioration of the electron beam spot characteristics due to spherical aberration, thereby improving the resolution of the water tube. The present invention relates to an electron gun of a color CRT tube in which beads are formed around the electron beam passing holes of the third electrode and the fourth electrode.

1 is a cross-sectional view of a general color CRT, as shown therein an electron gun 5 which emits an electron beam 6 in a glass bulb consisting of a panel 2 and a funnel 3 and A shadow mask 7 for selecting a color is provided, and a fluorescent film 8 on which the electron beam 6 collides is coated on the inner surface of the panel 3, and the funnel 3 of the water pipe 1 is provided. The deflection yoke 9 for scanning the electron beam 6 to the fluorescent film 8 is attached to the outside, and the electron gun 5 is enclosed in the neck part 4 of the funnel 3.

FIG. 2 is a schematic view showing the general structure of the electron gun 5 of FIG. 1, and as shown therein, the first electrode (1) having the electron beam 6 emitted from the cathode 13 fixed to the bead glass 20. 14) and accelerate to the second electrode (15). Focusing on the electrostatic lens formed by the potential difference between the third electrode 16 and the fourth electrode 17, and then collide with the fluorescent film 8 applied on the inner surface of the panel 2 to display an image on the same plane. In the description of the drawings, reference numeral 18 denotes a shield cup, and the third electrode 16 includes a third electrode cap 16a and a bottom 16b.

FIG. 3A is a plan view of the third electrode 16 of the electron gun of FIG. 2, and FIG. 3B is a sectional view of the third electrode 16 and the fourth electrode 17 of the electron gun of FIG. Three electron beam through holes a, b, c, (a ', b', c ') are perforated on the same plane of the P'-P' line or the PP line.

The conventional electron gun having such a structure has a difference between the voltage applied to the third electrode 16 (about 4-6 KV) and the voltage applied to the fourth electrode 17 (about 22 KV) as shown in FIG. 3B. The electrostatic lens E is formed. The electrostatic lens E serves to focus the electron beam 6 emitted from the cathode 13 onto the fluorescent film 8, which is very important for determining the focus characteristic. It works.

However, in such a conventional electron gun, the formation of the electrostatic lens is small, and the influence of spherical aberration is increased, thereby causing a problem of deteriorating the focus characteristic of the light receiving tube by emitting light scattered around the beam spot.

In addition, a color receiving tube is known which reduces spherical aberration and obtains an enlarged focusing lens by retreating the entire electrode surfaces of the third and fourth electrodes having three electron beam through holes into the electrode surface by the grooves. This not only complicated the manufacturing process of the color receiving tube, but also had a defect that the electrode surface was deformed by physical impact in the beading process in which glass was fused to each electrode.

In view of this, the present invention, as shown in Equation (1), the spherical aberration (CR) is proportional to the third square and the proportional constant (h) of the electron beam Q incident angle (Q) incident on the electrostatic lens system, The proportional constant h decreases the influence of spherical aberration by increasing the electrostatic lens according to the property inversely proportional to the size (diameter) of the electrostatic lens, and the electrode surface is physically bonded in the beading process in which glass is fused to each electrode. It is designed to prevent deformation by phosphorous impact in advance.

CR: spherical aberration

h: proportional constant

Q: incident angle of electron beam

This invention is described in detail with reference to the accompanying drawings as follows.

FIG. 4A is a plan view of the third electrode 16 of the electron gun of the present invention, and FIG. 4B is a sectional view of the third electrode 16 and the fourth electrode 17 of the electron gun of the present invention. The third electrode 16 and the fourth electrode 17 around the electron beam through holes a, b, c of the 16 and the electron beam through holes a ', b', c 'of the fourth electrode 17. The bead 21 is formed so as to protrude outward.

Here, the width W and the height H of the beads 21 are appropriately formed according to the diameters of the electron beam passing holes a, c and (a ', c') of the outside, that is, the electron beam passing holes a, c) When the diameters of (a ', c') are 4.Omm, the width W of the beads 21 is 1.Omm and the height H is 0.2-0.4mm, and the electron beam passes through When the diameters of the balls (a, c) and (a ', c') are 4.5 mm, the width W of the beads 21 is 0.7 mm and the height H is 0.3-0.5 mm, and the electron beam passes through When the diameters of the beams a, c and (a ', c') are 5.5 mm, the width H of the beads 21 is 0.5 mm, and the height H is 0.4-0.6 mm.

Such beads 21 may be pressed and pressed into the third electrode cap 16a and the fourth electrode 17 of the third electrode 16 during manufacture of the third electrode 16 and the fourth electrode 17. It is formed by.

Thus, the beads 21 are formed around the outer electron beam through holes (a, c) and (a ', c') of the third electrode cap 16a and the fourth electrode 17, and thus the third electrode cap 16a. And the equipotential lines formed between the fourth electrode 17 form one large electrostatic lens E as shown in FIG. 4B. As the electrostatic lens E increases in this manner, the proportional constant h decreases, thereby minimizing the influence of spherical aberration CR, as shown in Equation (1), thereby improving the resolution of the water pipe 1. .

In addition, the focus voltage applied to the third electrode 16 is applied to 22 to 45% of the voltage applied to the fourth electrode 17.

As described above, according to the present invention, the beads 21 are formed around the electron beam through holes (a, b, c), (a ', b', c ') of the third electrode 16 and the fourth electrode 17. As a result, the electrostatic lens E formed by the potential difference between the third electrode 16 and the fourth electrode 17 is expanded, and accordingly, the influence of the spherical aberration CR of the electron beam spot is reduced by about 30-40%. Correlation resolution can be improved, and the bead configuration can prevent the electrode surface from being deformed due to physical impact in the beading process in which glass is fused to each electrode.

Claims (4)

In an electron gun of a color CRT tube which forms an electrostatic lens by a potential difference between the third electrode 16 and the fourth electrode 17, the electron beam through holes (a) of the third electrode (16) and the fourth electrode (17). c), (a ', c') An electron gun of a color CRT, characterized in that the beads 21 are formed to protrude outward from the peripheral electrode surface. The width W of the bead 21 is 1.0 mm and the height H is 0.2 when the diameters of the electron beam through holes a, c and (a ', c') are 4. 0 mm. An electron gun of a color CRT tube, which is formed by being formed to be 0.4 mm. The width W of the bead 31 is 0.7 mm and the height H is 0.3 to 3, in the case where the diameters of the electron beam through holes a, c and (a ', c') are 4.5 mm. An electron gun of a color CRT tube, which is formed to be formed at 0.5 mm. The width W of the bead 21 is 0.5 mm and the height H is 0.4 to 4 when the diameters of the electron beam through holes a, c and (a ', c') are 5.5 mm. An electron gun of a color CRT tube, which is formed to be formed of 0.6 mm.