KR100258910B1 - Electron gun for cathode ray tube - Google Patents

Abstract

PURPOSE: An electron gun for cathode ray tube is provided to improve resolution of cathode ray tube by preventing deterioration of convergence characteristic when electron beam emitted from cathode is deflected to circumstance of fluorescent film. CONSTITUTION: A fronting triode part is composed of cathode(21), control electrode(22), screen electrode(23), double static focus electrode(24) forms quadruple lens, dynamic focus electrode(VD) and final acceleration electrode(26) are installed in an electron gun for cathode ray tube. Center of both side electron beam pass hole of focus electrode to form quadrupole lens is formed to be deflected toward inside against center of both side electron beam pass hole of dynamic focus electrode(VD). Later enlargement type electron beam pass hole(24H) and longitudinal enlargement type electron beam pass hole(25H) to compose of quadrupole lens are formed generally at exit side(24a) of static focus lens(24) and incident side of dynamic focus electrode(25) to compose of quadrupole lens separately. Appearance of electron beam pass hole to form quadrupole lens is able to be changed into several appearance according voltage licensing method.

Description

Electron gun for cathode ray tube

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

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

* Explanation of symbols for main parts of the drawings

21: cathode 22: control electrode

23: screen electrode 24: electrostatic focus electrode

25: dynamic focus electrode 26: final acceleration electrode

VF: Focus Voltage VD: Dynamic Focus Voltage

VE: anode voltage

The present invention relates to an electron gun for a cathode ray tube, and more particularly, to an electron gun for a cathode ray tube that can prevent the convergence characteristic of an electron beam from being lowered when a dynamic focus voltage is applied to a dynamic focus electrode forming an electron gun.

Typically, a cathode ray tube electron gun is mounted on the neck to emit hot electrons. The structure of the cathode ray tube electron cathode 11, the control electrode 12, and the screen electrode 13, which form a transposition triode as shown in FIG. And the first and second focus electrodes 14 and 15 and the final acceleration electrode 16 forming the auxiliary and main lenses, and the second fork electrode 15 so that three electron beams can converge at the fluorescent point. The center of both electron beam through holes 16H 'of the final acceleration electrode 16 is moved a predetermined length toward the electron beam through hole in the center with respect to the center of both electron beam through holes 15H' formed on the emission side of It is to be ground. In addition, a predetermined voltage is applied to each of the electrodes configured as described above. In this case, a predetermined electrostatic focus voltage vf is applied to the first focus electrode 14, and the electrostatic capacitance is applied to the second focus electrode 15. A dynamic focus voltage vd is applied to the focus voltage vf as a base voltage and synchronized with the output signal of the deflection yoke.

In the conventional cathode ray tube electron gun configured as described above, an electron lens is formed between each electrode by applying a predetermined voltage to each electrode so that hot electrons emitted from the cathode 11 are focused and accelerated to be rendered at each fluorescent point of the fluorescent film. When the focused and accelerated hot electrons, i.e., the electron beam, are deflected to the periphery of the fluorescent film, a dynamic focus voltage (vd) synchronized with the output signal of the deflection yoke is applied to the second focus electrode (15). The strength of the main lens is weakened between the electrode 15 and the final acceleration electrode 16, so that the convergence of the two electron beams is not accurate. In more detail, when the hot electrons emitted from the cathode 11 are scanned to the center portion of the fluorescent film, the second dynamic electrode 15 has the lowest dynamic focus voltage vd equal to the electrostatic focus voltage vf. Since it is applied, there is no change in the intensity of the common large-diameter lens formed between the electron beam passing holes on both sides of the second focusing electrode 15 and the final accelerating electrode 16, so that the electron beam can be converged to one fluorescent point. However, when the electron beam is scanned to the periphery of the fluorescent film, the dynamic focus voltage (vd) in synchronization with the deflection signal is applied to the second focus electrode (15), so that between the second focus electrode (15) and the final acceleration electrode (16). As the potential difference becomes small, the common large-diameter lens formed thereby is weakened, so that accurate convergence of the three electron beams is not achieved. Therefore, the color purity of the image formed by the cathode ray tube employing this electron gun is lowered, and there is a problem that the resolution due to miss convergence is lowered.

The present invention has been made to solve the above problems, and an object thereof is to provide an electron gun for a cathode ray tube that can prevent a change in convergence characteristics according to the application of a dynamic focus voltage.

Another object of the present invention is to provide an electron gun for a cathode ray tube which can improve the color purity of a cathode ray tube employing the electron beam emitted from three electron guns arranged in an in-line arrangement at one point.

In order to achieve the above object, the present invention provides a cathode ray tube electron gun comprising a cathode, a control electrode, and a screen electrode forming a pre-triode, an electrostatic focus electrode forming a quadrupole lens, a dynamic focus electrode, and a final acceleration electrode. ,

The centers of the two electron beam passing holes of the focus electrode forming the quadrupole lens may be shifted inward with respect to the centers of the two electron beam through holes of the dynamic focus electrode.

As shown in FIG. 2, the cathode ray tube electron gun according to the present invention includes a cathode 21, a control electrode 22, and a screen electrode 23 that form an anterior triode, and an electrostatic focus electrode for focusing and accelerating an electron beam. 24), the dynamic focus electrode 25 and the final acceleration electrode 26. Here, the emissive side surface 24a of the electrostatic focus electrode 24 constituting the quadrupole lens and the incident side surface 25a of the dynamic focus electrode 25 are each of an elongated electron beam through hole 24H for forming a quadrupole lens. ) And a horizontal electron beam through hole (25H) are formed, and the shape of the electron beam through hole forming the quadrupole lens can be changed in various forms depending on the voltage application method. Inside the dynamic focus electrode 25 and the final acceleration electrode 26, internal electrodes 25 ′ and 26 ′ having independent small-diameter electron beam passing holes 25H ′ and 26H ′ are respectively provided. .

A predetermined potential is applied to each electrode, and the electrostatic focus voltage VF is applied to the electrostatic focus electrode 24, and the dynamic focus voltage VD is applied to the dynamic focus electrode 25 in synchronization with a deflection signal. The high voltage anode voltage VE is applied to the final acceleration electrode 26. (VF VD VE) and the centers of the electron beam passing holes 25H on both sides of the dynamic focus electrode 25 forming the quadrupole lens by applying a predetermined potential to each electrode. The predetermined length is eccentric to the outer side in the center of the both-side electron beam through hole 25H of 24. As shown in FIG.

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

In the cathode ray tube according to the present invention, a predetermined electrostatic lens is formed between each electrode as a predetermined potential is applied to each electrode, and the electron beam fluoresces the state in which the electrostatic lens is formed and the state in which the electron beam is converged. If the description is divided into the state that is injected into the center and the periphery of the membrane.

First, when the electron beam emitted from the cathode 21 is scanned to the center portion of the fluorescent film, the dynamic focus voltage VD equal to the focus voltage VF is applied to the dynamic focus electrode 25 and the dynamic focus is applied. The main lens is formed between the electrode 25 and the final acceleration electrode 26. Therefore, the electron beam emitted from the cathode 21 is preliminarily focused and accelerated, and finally focused and accelerated by the main lens to be landed on the fluorescent film. Between the dynamic focus electrode 25 and the final accelerative electrode constituting the main lens, By the common large-diameter lens, both electron beams are converged to the center electron beam side and landed in the fluorescent film at the best state.

When the electron beam emitted from the cathode 21 is scanned to the periphery of the fluorescent film, the dynamic focus voltage VD is applied to the dynamic focus electrode 25 in synchronization with the deflection signal. The long side electron beam through hole 24H and the long side electron beam through hole 25H are respectively formed on the emission side surface 24a and the incident side surface 25a of the dynamic focus electrode 25, respectively. A polar lens is formed, and a main lens is formed between the dynamic focus electrode 25 and the final acceleration electrode 26. Therefore, the electron beam emitted from the cathode is focused and accelerated by the quadrupole lens after preliminary focusing and acceleration, and the electron beam is elongated by the quadrupole effect and finally focused and accelerated by the main lens. Landing. As described above, the state in which the electron beam is emitted from the cathode 21 and landed on the fluorescent film and the state in which both electron beams are converged to the center electron beam side will be described in more detail.

First, the electron beam emitted from the cathode 21 passes through the quadrupole lens formed between the electrostatic focus electrode 24 and the dynamic focus electrode 25. The dynamic focus electrode 25 of the quadrupole lens forms the quadrupole lens. Since the center of the elongated electron beam through hole 24H formed on the emission side of the electrostatic focusing electrode 24 is eccentric inwardly rather than the center of the horizontally elongated electron beam through hole 25H formed on the incident side, there is an asymmetry between them. The quadrupole lens is formed so that the electron beams on both sides are concentrated toward the electron beam passing hole in the center. The diverged electron beams pass through the outer edge of the main lens formed between the dynamic focus electrode 25 and the final acceleration electrode 26, and are converged to the electron beam side of the center. Therefore, the electron beam emitted from the cathode 21 is landing in the fluorescent film at the best state.

As described above, the electron gun for the cathode ray tube of the present invention can fundamentally prevent the convergence characteristic from deteriorating when the electron beam emitted from the cathode is deflected to the periphery of the fluorescent film, thereby improving the resolution of the cathode ray tube employing the same. Have

Claims (5)

In a cathode ray tube electron gun comprising a cathode, a control electrode, and a screen electrode forming a pre-triode, a plurality of electrostatic focus electrodes forming a quadrupole lens, a dynamic focus electrode, and a final accelerating electrode, a focus forming the quadrupole lens An electron gun for cathode ray tubes, characterized in that the centers of the electron beam passing holes on both sides of the electrode are formed to be biased with respect to the centers of the electron beam passing holes on both sides of the dynamic focus electrode. The electron gun for a cathode ray tube according to claim 1, wherein the electron beam through hole forming the quadrupole lens is a longitudinal electron beam through hole formed on the emission side of the electrostatic focus electrode and a transverse electron beam through hole formed on the incident side of the focus electrode. . 3. The center of an elongated electron beam through hole positioned outside the dynamic focus electrode is shifted outward from a center of the outer elongated electron beam through hole formed in the dynamic focus electrode. Electron gun for cathode ray tube. The electron gun for cathode ray tube according to claim 1, wherein the center of the outer electron beam through hole formed on the emission side of the focusing electrode is shifted inward from the center of the electron beam through hole of the dynamic focus electrode. The electron gun for a cathode ray tube according to claim 1, wherein the center of the outer electron beam through hole formed on the incident side of the dynamic focus electrode is formed outside the center of the outer electron beam through hole formed on the incident side of the focusing electrode.