KR940006548Y1 - Electron gun for c-crt - Google Patents

Abstract

No content.

Description

Electron gun for color cathode ray tube

1 is a sectional view showing a conventional electron gun for color cathode ray tubes.

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

* Explanation of symbols for main parts of the drawings

1: cathode 2: control electrode

3: screen electrode 4: focus electrode

41: first focus electrode 42: second focus electrode

43: third focus electrode 44: first auxiliary electrode

44a: Longitudinal electron beam passing hole (of first auxiliary electrode)

45: second auxiliary electrode

45a: Horizontal electron beam through hole (of the second auxiliary electrode)

The present invention relates to an electron gun for a color cathode ray tube, and more particularly, to an electron gun for a color cathode ray tube having a focus electrode improved to minimize the distortion of an electron beam spot landing on a fluorescent surface.

Usually, the electron gun encapsulated in the neck portion of the cathode ray tube emits hot electrons, as shown in FIG. 1, the cathode 1, the control electrode 2, the screen electrode 3, and the bipotential, which form the transposed triode part. The first focusing electrode 6 and the second focusing electrode 7 constituting the auxiliary auxiliary electrostatic lens, and the final acceleration electrode 8 disposed adjacent to the second focusing electrode 7 to form a bipotential main capacitive lens 8 It is configured to include. In addition, the first focusing electrode 6 has an elongated electron beam through hole 6a formed at the exit side, and a transverse electron beam through hole 7a formed at the granular side of the second focus electrode 7 opposite thereto. A focus voltage Vf is applied to the first focus electrode 6, and a focus voltage Vf is applied to the first focus electrode 7 as a base voltage, and a dynamic focus voltage synchronous with a deflection signal of the deflection yoke. Vd) is applied, and the anode voltage Ve is applied to the final acceleration electrode 8.

In the electron gun for the conventional color cathode ray tube configured as described above, as a predetermined potential is applied to each electrode, a pre-focus lens is formed between the screen electrode 3 and the first focus electrode 6, and the first and second focus electrodes ( 6) (7), a bipotential type secondary capacitive lens is formed, and a bipotential type primary capacitive lens is formed between the second focus electrode 7 and the final acceleration electrode 8.

Accordingly, the electron beam emitted from the cathode 1 is prefocused and accelerometer in the prefocus lens, and the electron beam passing through the prefocus lens is formed by the first and second focus electrodes 6 and 7. After focusing and accelerating by the potential auxiliary capacitive lens, the terminal is finally connected and accelerated by the bipotential main capacitive lens formed between the second focusing electrode 7 and the final accelerating electrode 8 and then landed on the fluorescent film. However, since the electron gun is configured to apply the dynamic focus voltage Vf to the second focus electrode 7, the bipotential formed between the second focus electrode 7 and the final acceleration electrode 8 by the dynamic focus voltage. The magnification of the type electrostatic lens is changed. That is, as the dynamic focus voltage Vd higher than the focusing electric charge Vf is applied to the second focus electrode 7, the voltage difference between the second focus electrode 7 and the final acceleration electrode 8 is changed. As the magnification of the bipotential type capacitive lens formed on the lens is changed, the focusing distance of the electron beam is changed, thereby reducing the convergence characteristic of the electron beam.

The present invention was conceived in view of the above-described problems, and the electron gun for color cathode ray tube which stabilized the convergence characteristics by preventing the change of magnification of the final acceleration and focusing bipolar potential electrostatic lens due to the dynamic focus voltage. The purpose is to provide.

In order to achieve the above object, the present invention provides a cathode electrode for a color cathode ray tube including a cathode, a control electrode, and a screen electrode, and a focus electrode and a final acceleration electrode, which constitute a pre-triode, and wherein the focus electrode comprises: It is formed by separating the first, second, and third focus electrodes to which the focus voltage is applied, and the longitudinal electron beam passes through which the red, green, and blue electron beams pass, respectively, with a constant voltage applied between the first and second focus electrodes. A first auxiliary electrode having a hole is provided, and a first auxiliary electrode having a horizontal electron beam passing hole through which a red, green, and blue electron beam passes, is applied with a dynamic focus voltage between the second and third focus electrodes. There is a characteristic to it.

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

Figure 2 shows the electron gun for the color cathode ray tube according to the present invention. It comprises a cathode (1), a control electrode (2) and a screen electrode (3) forming a pre-triode tube portion, a focus electrode (4) and a final acceleration electrode (5) forming a main lens. The focus electrode 4 is separated into first, second and third focus electrodes 41, 42 and 43 to which the focus voltage Vf is applied, and the first and second focus electrodes 41 are formed. A constant voltage (Vs) is applied between the 42 and 42, and the first auxiliary electrode 44 having three long electron beam through holes 44a through which red, green, and blue electron beams pass is provided. In addition, a dynamic focusing voltage Vd is applied between the second and third focus electrodes 42 and 43, and a second electron beam through hole 45a having a horizontally shaped red, green, and blue electron beam passes therethrough. The auxiliary electrode 45 is provided, and the anode voltage Ve is applied to the final acceleration electrode 5. In this case, it is preferable that the same voltage as the constant voltage Vs applied to the first auxiliary electrode 45 is applied to the screen electrode 3.

In the electron gun for a color cathode ray tube according to the present invention configured as described above, as a predetermined voltage is applied to each electrode, a prefocus lens is formed between the screen electrode 3 and the first focus electrode 41, and the first focus is formed. A first universal auxiliary capacitive lens is formed by the electrode 41, the first auxiliary electrode 44, and the second focus electrode 42, and the second focus electrode 42, the second auxiliary electrode 45, and The second unipotene grain type auxiliary capacitive lens is formed by the third focus electrode 43.

Then, a bipotential-type capacitive lens is formed by the third focus electrode 43 and the final acceleration electrode 5. Therefore, the electron beam emitted from the cathode 1 is prefocused and accelerated by the prefocus lens, weakly focused in the vertical direction and strongly focused in the horizontal direction by the first universal potential adjustment lens. The electron beam spot passing through this is strongly concentrated in the vertical direction and weakly focused in the horizontal direction by the second potential-type secondary capacitive lens, so that the electron beam spot passing through the bi-potential primary capacitive lens and landing on the fluorescent surface is almost circular. Will be In addition, since the dynamic focus voltage Vd is applied to the second auxiliary electrode 45 provided between the second and third focus electrodes 42 and 43, the third focus electrode V3 is applied when the dynamic focus voltage Vd is applied. 43) and the voltage difference between the final acceleration electrode 5 does not change, so that the magnification of the bipotential main capacitive lens formed between the third focus electrode 43 and the final acceleration electrode 5 does not change. The convergence characteristic of becomes stable.

As described above, in the electron gun for a color cathode ray tube of the present invention, a focus electrode is formed by separating the first, second and third focus electrodes, respectively, between the first, second focus electrodes and the second and third focus electrodes. A first auxiliary electrode having a longitudinal electron beam passing hole and a second auxiliary electrode having a horizontal electron beam passing hole are installed, and a dynamic focus voltage is applied to the second auxiliary electrode, thereby minimizing the outer beam of the electron beam spot landing on the fluorescent surface. As a result, the magnification change of the bipotential main capacitive lens due to the dynamic focus voltage can be prevented, thereby making the convergence characteristic of the electron beam stable.

Claims (2)

In a color cathode ray tube electron gun including a cathode, a control electrode and a screen electrode forming a pre-triode, and a focus electrode and a final acceleration electrode forming a main lens, the focus electrode 4 is applied with a focus voltage Vf. Separately formed into first, second and third focus electrodes 41 and 42 and 43, and a constant voltage Vs is applied between the first and second focus electrodes 41 and 42, and red and green colors are applied. And a first auxiliary electrode 44 having an elongated electron beam through hole 44a through which blue electron beams pass, respectively, and between the second and third focus electrodes 42 and 43. An electron gun for a color cathode ray tube, characterized in that a first auxiliary electrode (45) having a horizontal electron beam through hole (45a) through which red, green, and blue electron beams are applied is provided. The electron gun for a color cathode ray tube according to claim 1, wherein a constant voltage equal to a constant voltage applied to said first auxiliary electrode (44) is applied to said screen electrode (3).