KR940010988B1 - Electron gun for color cathode-ray tube - Google Patents

Abstract

The electron gun for reducing the moire phenomenon includes four focus electrodes (14-17), and a final acceleration electrode (18). The holes (14H,16H') passing the electron beam, of which vertical side is longer than the horizontal one, are formed on the outlet parts (14b,16b) of the electrodes (14,16). The holes (16H,17H) passing the electron beam, of which horizontal side is longer than the vertical one, are formed on the inlet parts. (16a,17a) of the electrodes (16,17). The constant voltage (vs) is applied to the electrode (15) and the focus voltage (vf) being higher than the constant voltage is applied to the electrode (16). The dynamic voltage (vd) being synchronized to the deflection signal is applied to the electrode (17).

Description

Electron gun for colored cathode ray tube

1 shows a conventional electron gun for a cathode ray tube, (a) is a cross-sectional view in which vertical and horizontal cross-sections are coupled around a center line, and shows a method of applying a voltage, and (b) shows a method for applying a voltage to the fluorescent film by the electron gun The cross section of the landing electron beam is shown.

2 is a view showing the electron gun for the color cathode ray tube according to the present invention, (a) is a cross-sectional view of the vertical and horizontal cross-section coupled to the center line, showing the voltage applied state, (b) is the electron gun shown in (a) It is shown by visualizing the cross section of the electron beam landing by.

* Explanation of symbols for main parts of the drawings

11 cathode 12 control electrode

13 screen electrode 14 first focus electrode

15: second focus electrode 16: third focus electrode

17: fourth focus electrode 18: final acceleration electrode

vs: constant voltage vf: focus voltage

vd: Dynamic focus voltage

The present invention relates to a color cathode ray tube, and more particularly, to an electron gun for a color cathode ray tube mounted on a neck portion of a cathode ray tube to emit an electron beam.

Typically, an electron gun for a cathode ray tube is enclosed in a neck portion of a funnel encapsulated with a panel on which a fluorescent film is formed, and there are various types according to the type and characteristics of a cathode ray tube. The resolution of a cathode ray tube is a cross section of an electron beam emitted from an electron gun. Since it depends on the size of, it is important that it is emitted from the electron gun and accurately landed at the fluorescent point of the fluorescent film. However, the cathode ray tube has a predetermined geometric curvature on the screen surface, and a difference in focal length occurs when the electron beam emitted from the electron gun is landed to the center and the periphery of the screen surface, and thus the cross section of the electron beam landing on the periphery of the screen is transverse. There was a problem in that halo occurred in a long form around it.

Figure 1 shows an embodiment of a conventional electron gun to solve this problem.

This includes a cathode (2), a control electrode (3) and a screen electrode (4) forming an anterior triode, and first, second, third and fourth focus electrodes (5) ((6) (7) ( 8) and a final acceleration electrode 9 disposed adjacent to the fourth focus electrode 8 to form a main lens, the emission side of the third focus electrode 7 and the fourth focus electrode. An elongated electron beam through hole 7H and a horizontal electron beam through hole 8H are respectively formed on the incident side of (8), and a predetermined voltage is applied to each electrode constituting the electron gun. A predetermined constant voltage vs is applied to the screen electrode 4 and the second focus electrode 6, and a focus voltage vf higher than the constant voltage vs is applied to the first and third focus electrodes 5 and 7. Is applied, a dynamic focus voltage (vd) is applied to the fourth focus electrode (8) in synchronization with a deflection signal, and to the final acceleration electrode (9). A high voltage anode voltage ve is applied.

The cathode electron tube 1 configured as described above has a unipotential type first auxiliary electrostatic lens 40 between the first, second and third focus electrodes 5, 6 and 7 as a predetermined voltage is applied to each electrode. And a bipotential type second auxiliary electrostatic lens 50 is formed between the third and fourth focus electrodes 7 and 8, and between the fourth focus electrode 8 and the final acceleration electrode 9. In the main electrostatic lens 60 is formed. Therefore, when the electron beam emitted from the cathode 2 is scanned into the central portion of the fluorescent film formed on the inner surface of the panel, it is connected and accelerated by the first auxiliary electrostatic lens 40 and the main electrostatic lens 60 to form a central portion of the fluorescent film. Will land in its best state. When the electron beam emitted from the cathode 2 is deflected to the main surface portion of the fluorescent film, the third and fourth focuses are applied to the fourth focus electrode 8 by applying a dynamic focus voltage v d in synchronization with a deflection signal. Since the quadrupole lens, which is the second auxiliary electrostatic lens 50, is formed between the electrodes 7 and 8, the electron beam emitted from the cathode 2 is diverged in the vertical direction by the quadrupole lens and is horizontal. Direction is focused and passes through the main electrostatic lens 60, which is weakened as the dynamic focus voltage vd is applied to the fourth focus electrode 8 while the electron beam cross section is elongated. (Orbit of the electron beam shown by the dotted line in FIG. 1)

Accordingly, the vertical direction of the electron beam passing through the main electrostatic lens 60 passes through the outer edge of the main electrostatic lens 60 and the outside of the non-uniform magnetic field region of the deflection yog, so that the electron beam cross section lands on the periphery of the fluorescent film. Although it can eliminate the halo phenomenon formed in the vertical section of the electron beam is very small compared to the center. Since the horizontal electron beam passing through the main lens is weakly focused past the center of the main lens, it is deflected and diverged by a non-uniform magnetic field of the deflection yoke, so that its cross section is smaller than the horizontal size of the electron beam landing at the center of the fluorescent surface. Will become large.

As a result, the cross section of the electron beam landing at the periphery of the fluorescent film forms a horizontal cross-section as shown in FIG. 2b, so that a uniform electron beam cross section cannot be achieved in the entire fluorescent film, and the resolution of the cathode ray tube employing the same can be improved. There was no problem.

The present invention has been made to solve the above problems, it is possible to uniformly form the electron beam cross-section landing on the entire fluorescent film of the cathode ray tube, to improve the resolution of the sound tube by reducing the moire (moire) phenomenon in the periphery of the screen It is an object of the present invention to provide an electron gun for a color cathode ray tube.

In order to achieve the above object, the present invention is provided so as to be adjacent to the first, second, third, and four focus electrodes forming the auxiliary lens and the cathode, the control electrode, the screen electrode, and the fourth focus electrode. An electron gun for a color cathode ray tube having a final accelerating electrode, wherein an emission side of the third focus electrode and an emission side of the third focus electrode and an emission side of the third focus electrode Longitudinal electron beam through holes and transverse electron beam through holes are respectively formed on the incident side of the fourth focus electrode, a predetermined constant voltage is applied to the second focus electrode, and the third focus electrode has a higher focus than the constant voltage. A voltage is applied, and a dynamic focus voltage in synchronization with the deflection signal is applied to the first and fourth focus electrodes. The.

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

FIG. 2 shows the electron gun 10 for the color cathode ray tube according to the present invention, which comprises a cathode 11, a control electrode 12 and a screen electrode 13, and a unipotential type first auxiliary auxiliary electrode forming a pre-triode. The bi-potential type second auxiliary electrostatic lens 200 is installed to be adjacent to the first, second, and third focus electrodes 14, 15, 16, and the third caustic electrode 16 forming the electrostatic lens 100. And a final acceleration electrode 18 forming the main electrostatic lens 300 together with the fourth focus electrode 17. Longitudinal electron beam through holes 14H and 16H 'are formed on the emission side surfaces 14a and 16b of the first and third focus electrodes 14 and 16 of the electrodes, and the third and fourth focus electrodes ( On the incident side surfaces 16a and 17a of the 16 and 17, horizontal electron beam passing holes 16H and 17H are formed.

In addition, a predetermined voltage is applied to each electrode constituting the electron gun 10. In detail, a predetermined constant voltage vs is applied to the second focus electrode 15, and the third focus electrode is applied. A focus voltage vf higher than the constant voltage vs is applied to the 16, and a dynamic focus voltage vd synchronized with a deflection signal is applied to the first and fourth focus electrodes 14 and 17. A high voltage isoed voltage ve is applied to the acceleration electrode 18.

Preferably, the second focus electrode 15 is applied to the screen electrode 13 and the coin position, and the dynamic focus voltage vd is set to the focus voltage vf as an electromotive voltage and synchronized with a deflection signal. It is preferable to apply a voltage. The longitudinal electron beam passing holes 14H and 16H 'and the horizontal electron beam passing holes 16H' and 17H are preferably formed in a rectangular shape or an elliptical shape. Reference numeral 400 is a visual representation of the non-uniform magnetic field of the deflection yoke with an optical lens.

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

As a predetermined voltage is applied to each electrode constituting the electron gun 10, the electron beam emitted from the cathode 11 is scanned by a fluorescent film to form one pixel, and the pixels are gathered to form a screen. In this case, the scanning state of the electron beam is divided into a central part and a peripheral part of the fluorescent film as follows.

First, when the electron beam is scanned to the center of the fluorescent film, the trajectory of the electrostatic lens and the electron beam is shown in FIG. Since the electron beam emitted from the electron gun is not deflected by the deflection yoke of the electron beam when the electron beam is scanned to the center portion of the fluorescent film, a first auxiliary portion formed between the first, second and third focus electrodes 14, 15 and 16 is provided. The electrostatic lens 100 is a first quadrupole lens formed between the first quadrupole lens 101 and the second focus electrode 15 formed between the first focus electrode 14 and the second focus electrode 15. A second quadrupole lens 102 formed between the 101 and the second focusing electrode 15 and the third focusing electrode 16 is included. Also, between the third and fourth focus electrodes 16 and 17, a dynamic focus voltage vd that is the base voltage and is synchronized with a deflection signal is not applied to the fourth focus electrode 17. Therefore, the second auxiliary electrostatic lens 200 is not formed.

Accordingly, the electron beam emitted from the cathode 11 is preliminarily focused and accelerated while passing through the first and second quadrupole lenses 101 and 102 of the first auxiliary electrostatic lens 100 and the main electrostatic lens 300. The final focusing and accelerating through the) will land in the best state in the center of the fluorescent film. In more detail, the first quadrupole lens 101 has a focusing force in the vertical direction by a longitudinal electron beam through hole 14H formed on the emission side of the first focus electrode 14 and is horizontal. Direction, and the second quadrupole lens 102 has a diverging force in the vertical direction by a horizontal electron beam passing hole 16H formed on the incident side of the third focus electrode 16. It has focusing power in the horizontal direction. Therefore, the electron beam emitted from the cathode 11 passes through the first and second quadrupole lenses 101 and 102 of the first auxiliary electrostatic lens 100 and receives the focusing and acceleration force, but the cross section of the electron beam is not changed. Landing in the center in the best state with the fluorescent film.

In addition, when the electron beam emitted from the cathode 11 is deflected to the periphery of the fluorescent film, the trajectory of the electrostatic lens and the electron beam formed between the electrodes is shown by a solid line.

Since the dynamic focus voltage vd in synchronization with the deflection signal is applied to the first and fourth focus electrodes 14 and 17, the first auxiliary electrostatic lens is formed between the first and second focus electrodes 14 and 15. The first quadrupole lens 101 of 100 is relatively strong, and a second auxiliary electrostatic lens 200 is formed between the third and fourth focus electrodes 16 and 17.

Accordingly, in the vertical direction of the electron beam emitted from the cathode 11, a strong focusing action is received by the first quadrupole lens 101 of the first auxiliary electrostatic lens 100, and the electron beam receives the focusing force. The horizontal direction of the light is received a weak divergence while passing through the second quadrupole lens 102 and the second auxiliary electrostatic lens 200, and focused and accelerated while passing through the main electrostatic lens 300, landing on the periphery of the fluorescent film In this case, the vertical direction of the electron beam cross section has the same size as the vertical cross section of the electron beam cross section landing in the center. In addition, the horizontal direction of the electron beam emitted from the cathode 11 of the electron gun 10 is strongly emitted by the first quadrupole lens 101, and the second quadrupole lens 102 and the second auxiliary While passing through the electrostatic lens 200 receives a strong focusing force, and after passing through the main lens and is finally focused and accelerated is received by the non-uniform magnetic field of the deflection yoke is landing on the main surface of the fluorescent film, at this time The cross-sectional size in the horizontal direction of the electron beam landing on the film has approximately the same size as the horizontal direction of the electron beam landing on the central portion of the fluorescent film. Therefore, the electron beam cross section landing on the main surface portion of the fluorescent film has a substantially circular shape as shown in FIG. 2B.

As described above, the electron gun for the color cathode ray tube according to the present invention changes the intensity of the first quadrupole lens of the first auxiliary electrostatic lens in synchronization with the intensity of the second auxiliary electrostatic lens, thereby horizontally and vertically of the electron beam emitted from the cathode. By changing the cross section of the residual beam acting as a rectangle, it is possible to form a uniform electron beam cross section in the entire fluorescent film. In particular, the electron gun as described above has an advantage of preventing the central electron beam from being distorted in the horizontal shape when the common large-diameter electron beam passing hole is adopted.

Claims (3)

First, second, third, and four focus electrodes forming a cathode, a control electrode, and a screen electrode and an auxiliary electrostatic lens forming the prepolar triode are disposed adjacent to the fourth focus electrode to form a main electrostatic lens. In the electron gun for a colored cathode ray tube, an elongated electron beam through hole (14H) (16H ') is formed in the emission side surfaces (14b) and (16b) of the first and third focus electrodes (14) and (16), respectively. On the incidence side surfaces 16a and 17a of the 3 and 4 focus electrodes 16 and 17, horizontal electron beam through holes 16H and 17H are formed, respectively, and the second focus electrode 15 has a predetermined constant voltage. (vs), the constant voltage vs is applied to the third focus voltage 16, and a higher focus voltage vf is applied to the deflection signal to the first and fourth focus electrodes 14 and 17. An electron gun for color cathode ray tubes, characterized by applying a synchronous dynamic focus voltage (vd). The electron gun for color cathode ray tubes according to claim 1, wherein the second focus electrode (15) is applied on the screen electrode (13) and a coin. The electron gun for a color cathode ray tube according to claim 1, wherein the dynamic focus voltage (vd) is higher than the focus voltage (vf).