KR940007248B1 - Electron gun for c-crt - Google Patents

Abstract

The electron gun for a color cathode ray tube includes a cathode, a control electrode, a screen electrode, and other electrodes for forming unipotential and bipotential static lenses, wherein the second focus electrode of the unipotential static lens is divided into first and second electrodes, and a recess is formed on the incoming side of the first electrode and on the outgoing side of the second electrode, perpendicular to the periphery of the electron beam passing holes.

Description

Electron gun for colored cathode ray tube

1 is a cross-sectional view of an electron gun for a conventional color cathode ray tube.

2 is a cross-sectional view of an electron gun for a color cathode ray tube according to the present invention.

3 is a perspective view showing an extract of the focus electrode of the second electrode shown in FIG.

4 is a perspective view showing another example of the second focus electrode shown in FIG.

* The name of the symbol for the main part of the drawing

11: cathode 12: control electrode

13 screen electrode 14 first focus electrode

15: second focus electrode 16: third focus electrode

17: final acceleration electrode Vf: focus voltage

Ve: Anode Wood Voltage

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun for color cathode ray tubes, and more particularly, to an electron gun for color cathode ray tubes, in which a second focus electrode constituting an auxiliary electrostatic lens system is improved.

Typically, the electron gun encapsulated in the neck portion of the cathode ray tube emits hot electrons, as shown in FIG. 1, the cathode (2), the control electrode (3), the screen electrode (4), the auxiliary lens, and the main electrode, which form the pre-triode tube part, as shown in FIG. The first, second and third focus electrodes 5, 6, 7 and the final acceleration electrode 8 each having a circular electron beam passing hole formed by a lens are spaced apart from each other at predetermined intervals and are sequentially fixed. A predetermined voltage is applied to each electrode of the electron gun 1, and a predetermined focus voltage Vf is applied to the first and third focus electrodes 5 and 7, and the screen electrode 4 and the first electrode are formed. A predetermined constant voltage Vs is applied to the two focus electrodes 6, and a high-pressure enowood voltage Ve is applied to the final acceleration electrode 8.

In the conventional color cathode ray tube electron gun 1 configured as described above, as a predetermined potential is applied to each of the electrodes, a prefocus lens is formed between the screen electrode 4 and the first focus electrode 5, and the first and second electrodes are configured as described above. And a three-potential electrode (5), (6) and (7) to form a unipotential electrostatic lens, and the bipotential main lens is formed between the formulation three focus electrode (7) and the final acceleration electrode (8). do. Therefore, the electron beam emitted from the cathode 2 is preliminarily connected and accelerated in the prefocus lens, and the electron beams passing through the prefocus lens are transferred to the first, second and third focus electrodes 5, 6, and 7. After focusing and accelerating by the unipotential auxiliary capacitive lens formed by the fluorescence film, the fluorescent film is finally connected and accelerated by the bipotential main capacitive lens formed between the third focusing electrode 7 and the final acceleration electrode 8. Landing. However, the electron gun can focus the electron beam away from the main electrostatic lens by focusing the electron beam to reduce the divergence angle and spherical aberration of the electron beam, but deflect when the electron beam emitted from the electron gun is deflected toward the periphery of the fluorescent film. The distortion of the electron beam spot due to the deflection aberration of the yoke and the geometric curvature of the screen surface could not be solved fundamentally. Therefore, there is a problem that cannot improve the resolution of the cathode ray tube employing this.

The present invention has been made to solve the above problems, by improving the vertical divergence of the unipotential type electrostatic lens to lengthen the cross section of the electron beam can reduce the focus characteristics and spherical aberration, and furthermore, the resolution of the cathode ray tube employing the same The purpose is to provide an electron gun for a color cathode ray tube that can be improved.

In order to achieve the above object, the present invention is a color cathode ray tube electron gun comprising a cathode, a control electrode and a screen electrode constituting the pre-triode tube portion and a plurality of electrodes constituting the electrostatic lens and the bipotential electrostatic lens, Of the three electrodes constituting the unpotential type electrostatic lens, the center electrode is divided into first and second electrodes, and a predetermined length is introduced in the vertical direction from the edge of each electron beam through hole to the incident side of the first electrode and the exit side of the second electrode. Characterized in that the formed inlet portion.

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

According to the present invention shown in FIG. 2, the electron gun 10 for a color cathode ray tube is formed of a cathode and an electrode and a capacitive lens with the cathode 11 control electrode 12 and the screen electrode 13 forming the pre-triode tube portion. The final acceleration electrode 17 is positioned adjacent to the first, second and third focus electrodes 14, 15 and 16 and the third focus electrode 16 to form a bipotential main capacitive lens. The second focus electrode 15 positioned in the center of the three electrodes constituting the unpotential electrostatic lens has a plurality of first and second circular electron beam through holes 15H arranged in an inline manner. Separately formed into electrodes 15a and 15b, the incident side surface 15a of the first electrode 15a and the exit side surface 15s' of the second electrode 15b have the electron beam through hole according to the features of the present invention. Inlet portion 19 formed with a predetermined length inlet in the vertical direction from the edge of 15H. It is formed. Here, the inlet portion 19 formed in the first and second electrodes 15a and 15b is formed by pressing the first and second electrodes 15a and 15b as a press or as shown in FIG. An electrode piece 20 having an elongated through hole formed in a portion corresponding to the electron beam through hole 15H on the incident side surface 15c of the first electrode 15a and the emission side surface 15s' of the second electrode 15b. ) Are preferably attached to each other. In another embodiment of the second focusing electrode, as shown in FIG. 4, the inlet portions 19 as described above are formed on both sides of the single body 15e, and the inlet portion 19 is It is preferable to form by attaching the electrode pieces as described above, or to form the body (15e) by pressing as a press, or to sinter the metal powder.

A predetermined voltage is applied to each electrode of the electron gun 10, and a predetermined focus voltage 1Vf is applied to the first and third focus electrodes 14 and 16, and among the first focus electrodes 15. The first and second electrodes 15a and 15b are respectively applied to the potentials of the control electrode 12 and the screen electrode 13 to which the potential lower than the focus voltage Vf is applied, and to the final acceleration electrode 17. An anode voltage Ve of a higher voltage than the focus voltage Vf is applied.

When the second focus electrode 15 'is formed of a single body 15e, although not shown in the drawing, the second focus electrode 15' is applied to the screen electrode l3 and the coin.

Referring to the operation of the electron gun for the color cathode ray tube according to the present invention configured as described above are as follows.

First, as a predetermined potential is applied to the electrode forming the electron gun, a prefocus electrostatic lens is formed between the screen electrode 13 and the first focus electrode 14, and the first, second and third focus electrodes 14 ( Between the 15 and 16, a unpotential auxiliary capacitive lens is formed, and a bipotential main capacitive lens is formed between the third focus electrode 16 and the final acceleration electrode 17.

Accordingly, the electron beam emitted from the cathode 11 is pre-connected and accelerated by the prefocus electrostatic lens and is formed by the first, second and third focus electrodes 14, 15 and 16. It is focused and accelerated by the incident side surface 15s of the second focusing electrode 15 and the exit side surface l5s', that is, the first electrode 15a of the three electrodes constituting the unipotential auxiliary electrostatic lens. Since the inlet portion 19 having a predetermined length extending in the vertical direction from the edge of the electron beam through hole 15H is formed on the side and the emission side of the second electrode 15b, the unpotential type electrostatic lens has a vertical direction and a horizontal direction. As a result, strong divergence and weak focusing force are received, and in the horizontal direction, strong focusing force and weak diverging force are received, and the cross section forms an elongated shape. After passing through the unipotential type electrostatic lens, the final focused and accelerated by the bipotential type electrostatic lens formed between the elongated electron beam third focus electrode 16 and the final acceleration electrode 17 to be landed on the fluorescent film. The electron beam landing at the periphery of the fluorescent film has a circular cross section. In more detail, when the electron beam length-formed by the unipotential auxiliary electrostatic lens is deflected to the periphery of the fluorescent film, its cross section is compensated circularly by the disproportionated particle system of the deflection yoke, and the landing is optimally performed at the periphery of the fluorescent film Will be. Therefore, the astigmatism of the electron beam landing on the fluorescent film can be corrected.

As described above, the electron gun for the color cathode ray tube of the present invention fundamentally solves the astigmatism problem by forming inlets on both sides of the center electrode among the three electrodes formed of the unpotential auxiliary capacitive lens, and further improves the resolution of the cathode ray tube employing the same. Has the advantage

Claims (3)

In the electron gun for a color cathode ray tube having a cathode, a control electrode and a screen electrode forming a pre-triode tube portion, and a plurality of electrodes forming a unpotential type electrostatic lens and a bipotential type electrostatic lens, three electrodes of the unpotential type electrostatic lens The second focusing electrode l5 in the center is separated into the first and second electrodes 15a and l5b, and each electron beam through hole is formed on the incident side of the first electrode 15a and the exit side of the second electrode 15b. An electron gun for a color cathode ray tube, characterized by forming an inlet portion (10) drawn in a predetermined length in a vertical direction from the edge of 15H). The electron gun for color cathode ray tubes according to claim 1, wherein the first and second electrodes comprise one electrode. 2. The collar according to claim 1, wherein the inlet portion 10 of the center electrode l5 attaches the electrode pieces 20 having the longitudinal through-holes 21 formed on both sides of the center electrode, respectively. Electron gun for cathode ray tube.