KR100258904B1 - Electron gun for colored cathode ray tube - Google Patents

Abstract

The present invention discloses an electron gun for a color cathode ray tube.

According to the present invention, the final acceleration is performed to be adjacent to the cathode, the control electrode, the screen electrode, and the first, the second, the third, the fourth, and the fifth focus electrodes forming the auxiliary electron lens and the fifth focus electrode. A dynamic focus voltage having an electrode, a constant voltage is applied to the second focus electrode, a focus voltage higher than the constant voltage is applied to the first and fourth focus electrodes, and a dynamic focus voltage modulated in synchronization with a deflection signal to the third and fifth focus electrodes. This has the characteristic of being applied, which has the advantage of being able to obtain a uniform electron beam cross section in the entire fluorescent film and improving the resolution of the image.

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.

2A and 2B show the trajectory of the lens and the electron beam formed by the conventional color cathode ray tube electron gun shown in FIG.

Figure 3 is a cross-sectional view of the electron gun for color cathode ray tube according to the present invention.

4A and 4B are cross-sectional views showing visualizations of the trajectories of the electron lens and the electron beam formed by the electron gun of FIG.

* 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: fifth focus electrode

19: final acceleration electrode VS: constant voltage

VF: Focus Voltage VD: Dynamic Focus 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 that can obtain uniform focus characteristics when a residual beam is scanned into the central and peripheral portions of a fluorescent film.

Typically, the hot electrons emitted from the electron gun installed in the neck portion of the cathode ray tube are deflected by deflection yoke according to the position to be landed on the fluorescent film and landed on the fluorescent film to form one pixel, and these pixels are gathered to form an image. In order to improve the resolution of the image, the cross section of the electron beam emitted from the electron gun and landing on the fluorescent film should be as small as possible, and the focus characteristic of the electron beam emitted from the electron gun should be good. Conventionally, many electron guns have been developed to improve such characteristics, and FIG. 1 shows an example of a dynamic focus electron gun among these electron guns.

This includes the cathode 2, the control electrode 3, and the screen electrode 4, which form the anterior triode, and the first, second, third, and four focus electrodes 5, 6, 7, and 8 that form the main lens. ) And a final accelerating electrode 9, each having an elongated electron beam passing through the exit side surface 7a of the third focus electrode 7 and the incident side surface 8a of the fourth focus electrode 8, respectively. The hole 7H and the transverse electron beam passing hole 8H are formed. Each of the electrodes has a predetermined voltage, and the screen electrode 4 is applied with a constant voltage VS to the second focus electrode 6, and the constant voltage (V) is applied to the first and third focus electrodes 5 and 7. A focus voltage VF higher than VS is applied, and a dynamic focus voltage VD is applied to the fourth focus electrode 8 in which the deflection yoke is modulated in synchronization with the deflection signal.

In the conventional color cathode ray tube electron gun 1 configured as described above, the state of the voltage applied to each electrode is changed as the electron beam emitted from the electron beam is scanned to the center portion and the peripheral portion of the fluorescent film, and the action of the electron gun is directed to the center portion. When briefly described as being injected and when injected into the peripheral portion as follows.

First, when the electron beam emitted from the electron gun is scanned to the center portion of the fluorescent film, the dynamic focus voltage VD is applied to the fourth focus electrode 8 in synchronization with the deflection signal and lower than the focus voltage VF. As shown in FIG. 2, a unipotential auxiliary electron lens is formed between the first, second and third focus electrodes 5, 6, and 7, and the electron beam is between the third and fourth focus electrodes 7 and 8. The quadrupole lens which emits light is formed. A bipotential kettle lens is formed between the fourth focus electrode 8 and the maximum acceleration electrode 9.

Therefore, the electron beam emitted from the cathode 2 is preliminarily focused and accelerated in the unipotential electron lens, diverged by the quadrupole lens, incident on the kettle lens, and finally accelerated to be scanned at the center of the fluorescent film. When the electron beam emitted from the cathode 2 is scanned to the side of the fluorescent film, the fourth focus electrode 4 is modulated in synchronization with a deflection signal and has a dynamic focus voltage higher than the focus voltage VF. Since the VD) is applied, a quadrupole lens having a diverging force in the vertical direction and a focusing force in the horizontal direction is formed between the third and fourth focus electrodes 7 and 8 to the cathode 2. The emitted electron beam is strongly concentrated in the vertical direction and has a strong divergence in the horizontal direction, so that the cross section of the electron beam scanned in the periphery of the fluorescent film becomes horizontal. Therefore, the electron gun has a horizontal cross section of the electron beam scanned at the center of the screen, which is almost the same as the horizontal length, but the horizontal cross section of the electron beam scanned at the periphery of the screen is very long compared to the vertical length to form a horizontal shape. There was a problem that the resolution of the image cannot be improved without obtaining a uniform electron beam cross section. In particular, since the cross section of the cross section of the electron beam scanned at the periphery of the screen surface has a problem that a moire phenomenon occurs in the periphery of the image.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide an electron gun for a color cathode ray tube which can make the focus state and the cross section of the electron beam uniform on the typical light emitting surface and can prevent the moray phenomenon of the image.

Another object of the present invention is to provide an electron gun for a color cathode ray tube which can improve the resolution of the screen surface in the horizontal direction.

In order to achieve the above object, the present invention is provided so as to be adjacent to the cathode, the control electrode and the screen electrode forming the pre-triode, the first, the second, the third, the fourth, and the fifth focus electrodes forming the auxiliary electron lens. A final acceleration electrode forming a lens is provided, a constant voltage is applied to the screen electrode and the second focus electrode, a focus voltage higher than the constant voltage is applied to the first and fourth focus electrodes, and a deflection signal is applied to the third and fifth focus electrodes. It is characterized in that a dynamic focus voltage that is modulated in synchronism with H is applied.

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

3 shows the electron gun 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 the screen electrode 13, which form a transposition triode. The first, second, third, fourth and fifth focus electrodes 14, 15, 16, 17 and 18 arranged to be adjacent to each other to form an auxiliary electron lens and adjacent to the fifth focus electrode 18 It is provided with a final acceleration electrode 19 provided to form a main electron lens. Here, an elongated electron beam through hole 16H and an elongated electron beam through hole 17H are respectively formed on the emission side surface 16a of the third focus electrode 16 and the incident side surface 17a of the fourth focus electrode. Formed to form a first quadrupole lens, and an elongated electron beam through hole 17H 'is formed at the emission side surface 17b of the fourth focus electrode and the incident side surface 18a of the fifth focus electrode 18, respectively. And the transverse electron beam passing holes 18H are formed to form the second quadrupole lens.

A predetermined potential is applied to each electrode of the color cathode ray tube electron gun, and a constant voltage VS is applied to the second focus electrode, and the constant voltage VS is applied to the first and fourth focus electrodes 14 and 17. A higher focus voltage VF is applied, and a dynamic focus voltage VD modulated in synchronization with the deflection yoke is applied to the third and fifth focus electrodes 16 and 18. In this case, a voltage of 400 to 800 V is preferably applied to the constant voltage VS screen electrode 13 and the coin, and the focus voltage VF is preferably applied to a voltage of 6 to 10 KV and synchronized with the deflection signal. It is preferable to apply a voltage of 4 to 11 KV for the dynamic focus voltage VF that is modulated.

The final accelerating electrode 19 is applied with an enowood voltage VE of 25 to 30 KV.

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.

In the electron gun for the color cathode ray tube according to the present invention, the state of the voltage applied to each electrode and the state of the electrostatic lens formed between the electrodes are changed as the electron beam is scanned to the central portion and the side portion of the fluorescent film. When the electron beam emitted from is scanned into the central portion of the fluorescent film and when scanned into the peripheral portion of the fluorescent film will be described as follows.

4 shows the trajectory of the electrostatic lens formed between the electrodes of the electron gun and the electron beam scanned to the central and peripheral portions of the fluorescent film according to the present invention. (B) shows the trajectory of the electrostatic lens and the electron beam formed in the horizontal direction.

First, when the electron beam emitted from the cathode 11 is scanned to the center portion of the fluorescent film, the focus voltage VF applied to the first and fourth focus electrodes 14 and 17 is the third and fifth focus electrodes ( 16 and 18, the same voltage as that of the dynamic focus voltage VD is applied to the first and second focus electrodes 14, 15, and 16. The first and second quadrupole lenses are not formed between the four focus electrodes 16 and 17 and the fourth and fifth focus electrodes 17 and 18. Accordingly, the electron beam emitted from the cathode 11 is prefocused and accelerated in the electrostatic lens and finally focused and accelerated in the main lens as shown by the solid lines of FIGS. do.

When the electron beam emitted from the cathode 11 is scanned to the periphery of the fluorescent film, the dynamic focus voltage is applied to the third and fifth focus electrodes 16 and 18 and modulated in synchronization with the deflection signal of the deflection yoke. Since VD is applied higher than the focus voltage VF, a predetermined potential difference is generated between the third, fourth and fifth focus electrodes 16, 17 and 18. Accordingly, an electrostatic lens is formed between the first, second and third focus electrodes 14, 15 and 16, and a first quadrupole lens is formed between the third and fourth focus electrodes 16 and 17. A second quadrupole lens is formed between the fourth and fifth focus electrodes 17 and 18, and a main electrostatic lens is formed between the fifth focus electrode 18 and the final acceleration electrode 19. When divided into the direction and the horizontal direction described as follows.

First, as shown in FIG. 4A, the electrostatic lens in the vertical direction of the electron gun and the trajectory of the electron beam are formed, the elongated electron beam through hole 16H is formed on the emission side surface 16a of the third focus electrode 16. Since the incidence side surface 17a of the four focusing electrode 17 has a horizontal electron beam through hole 17H, the first quadrupole lens has a focusing force in the vertical direction and the fourth and fifth focusing electrodes 17 The second quadrupole lens formed between the first and the second quadrupole lenses is provided with an elongated electron beam through hole 17H 'on the exit side 17b and the incident side 18a of the fourth and fifth focus electrodes 17 and 18, respectively. Since the horizontal electron beam through hole 18H is formed and a relatively high voltage is applied to the fifth focus electrode 18 compared to the fourth focus electrode 18, it has divergence in the vertical direction. Therefore, the vertical component of the electron beam emitted from the cathode 11 is focused on the electrostatic lens and the first quadrupole lens as shown by the dotted line of FIG. 4a, and then strongly diverges from the second quadrupole lens. The final focused and accelerated longitudinal electron beam is compensated for by the uneven magnetic field of the deflection yoke and landed at the center of the fluorescent film.

As shown in FIG. 4B, an elongated electron beam through hole 16H is formed in the emission side surface 16a of the third focus electrode 16, as shown in FIG. 4B. Since the incidence side surface 17a of the four focus electrode 17 is formed with a horizontal electron beam through hole 17H, the first quadrupole lens has a diverging force in the horizontal direction and the fourth and fifth focus electrodes 17 The second quadrupole lens formed between (18) and the elongated electron beam through hole (17H ') on the exit side (17b) and the incident side (18a) of the fourth and fifth focus electrodes (17) (18), respectively; Since the horizontal electron beam through hole 18H is formed and a relatively high voltage is applied to the fifth focus electrode 18 compared to the fourth focus electrode 18, the focusing force is provided in the horizontal direction. Therefore, the vertical component of the electron beam emitted from the cathode 11 is emitted from the electrostatic lens and the first quadrupole lens and focused on the second quadrupole lens, as shown by the dotted line in FIG. 4b. And the accelerated horizontal electron beam compensates for the distortion caused by the nonuniform magnetic field of the deflection yoke and lands at the center of the fluorescent film so that the cross section of the electron beam is substantially circular.

In more detail, the first quadrupole lens diverges the electron beam passing through the electrostatic lens in the vertical direction in the horizontal direction and focuses the electron beam in the main lens even though the second quadrupole lens is focused in the vertical direction in the horizontal direction. There is no difference in size. Therefore, the electron beam has a strong + incidence angle in the vertical direction and a strong-incidence angle in the horizontal direction, and after passing through it, the action of the uneven magnetic field of the deflection yoke having diverging action in the compression horizontal direction is canceled out. At the periphery of the fluorescent film, a circular electron beam cross section can be obtained.

As described above, the electron gun for the color cathode ray tube of the present invention can uniformly form the electron beam spots landing on the entire fluorescent film so that the screen brightness can be uniform and the image resolution can be improved. Has the advantage of preventing.

Claims (7)

A cathode, a control electrode, a screen electrode, a first electrode, a second electrode, a third electrode, and a fifth focus electrode forming the auxiliary electron lens, and a final accelerating electrode forming the main lens. A constant voltage VS is applied to the second focus electrode 15, and a focus voltage VF higher than the constant voltage VS is applied to the first and fourth focus electrodes 14 and 17. And a five-focus electrode (16, 18) is applied with a dynamic focus voltage (VD) modulated in synchronization with a deflection time signal. The elongated electron beam through hole 16H is formed in the emission side surface 16a of the third focus electrode 16, and the transverse side shape is formed in the incident side surface 17a of the fourth focus electrode 17. An electron beam through-hole 17H of which is formed to form a first quadrupole lens, the electron gun for a color cathode ray tube, characterized in that. The elongated electron beam through hole 17H 'is formed in the emission side surface 17a of the fourth focus electrode 17, and is transverse to the incident side surface 18a of the fifth focus electrode 18. An electron gun for a color cathode ray tube, characterized in that a long electron beam through hole (18H) is formed to form a second quadrupole lens. The method of claim 1, wherein the constant voltage VS is applied with a voltage of 400 to 800 V, and the voltage of 6 to 10 KV is applied to the focus electrode VF, and the dynamic focus voltage VD is equal to 4 of the focus voltage VF. Electron gun for color cathode ray tube, characterized in that the voltage of 11 ~ 11KV is applied. The electron gun for a color cathode ray tube according to claim 1, wherein a focus voltage VF is applied higher than the dynamic focus voltage VD when the electron beam emitted from the electron gun is emitted to the center portion of the fluorescent film. The electron gun for a color cathode ray tube according to claim 1, wherein the dynamic focus voltage VD is applied higher than the focus voltage VF when the electron beam emitted from the electron gun is scanned to the periphery of the fluorescent film. The electron gun for a color cathode ray tube according to claim 1, wherein a voltage applied to said second focus electrode (15) is applied to said screen electrode and a coin.