KR20030089028A - The Electron Gun For The C-CRT - Google Patents

Abstract

PURPOSE: An electron gun is provided to allow for ease of control of astigmatism and achieve improved resolution by changing the thickness of the auxiliary electrode without causing changes of shape of electron beam passing hole. CONSTITUTION: An electron gun comprises a main electrode unit including a focusing electrode for focusing the electron beam emitted from a cathode toward a phosphor screen, and an anode. The main electrode unit includes an auxiliary electrode(171) on which red, green and blue electron beam passing holes are arranged in a line. The peripheral part of the electron beam passing hole formed at the center of the auxiliary electrode has a thickness which is partially different.

Description

Electron gun for the color cathode ray tube {The Electron Gun For The C-CRT}

The present invention relates to an electron gun for a color cathode ray tube, and more particularly, it is easy to adjust the astigmatism by changing the thickness of the auxiliary electrode around the electron beam through hole located in the center without changing the shape of the electron beam through hole in the auxiliary electrode, thereby improving the resolution. It relates to an electron gun for letting.

As shown in FIG. 1, the conventional colored cathode ray tube structure includes a front glass called panel 1 and a rear glass called funnel 2, and a fluorescent surface having a predetermined light emitting role therein, and the fluorescent surface. With an electron gun (8) for emitting an electron beam (11) for emitting light, a shadow mask (3) serving as color screening, a frame (4), a stud pin (6), and a spring (5) for welding and fixing the shadow mask. It is composed. In addition, the inner shield 7 which serves to shield the cathode ray tube so as to be less affected by external geomagnetism during operation is fixed to the frame 4 and is sealed with high vacuum.

The general principle of cathode ray tube operation is as follows. In the electron gun 8 embedded in the neck of the funnel 2, the electron beam 11 strikes the fluorescent surface formed on the inner surface of the panel 1 by the anode voltage applied to the cathode ray tube, and the electron beam reaches the fluorescent surface. Before the deflection yoke (9) is deflected up, down, left and right to form a screen. And there is a magnet to correct the trajectory so that the electron beam hits the phosphor accurately, thereby preventing poor color purity. In addition, since the cathode ray tube is made of high vacuum, it may be easily deflated due to external impact. To prevent this, the reinforcing band 10 is mounted on the skirt portion of the panel to disperse the stress of the cathode ray tube in a high vacuum state, thereby improving impact resistance. Secure.

The electron gun includes a cathode 12 generating an electron beam, a first electrode 13 spaced apart from the cathode by a predetermined distance, and a second electrode arranged at a predetermined distance from the first electrode to accelerate and focus the electron beam. 14) a main electrode part including a third electrode 15, a fourth electrode 16, and fifth electrodes 15, 17 and a sixth electrode 18, which are arranged at a predetermined distance from the fourth electrode. do. The electrodes are fixed by the bead glass while maintaining a constant interval, the electron gun is inserted into the neck glass constituting the neck portion of the funnel (2) and the neck glass is fused with the stem portion for applying a voltage to the electron gun from the outside And mounted on the cathode ray tube.

Referring to the operation of the electron gun, the heater 19 embedded in the cathode 12 receives the voltage applied to the stem pin to emit electrons, the emitted electrons by the formulation 1 electrode 13 as a control electrode Controlled, accelerated by the second electrode 14, partially focused by an UPF lens formed between the third electrode 15, the fourth electrode 16, and the fifth electrode 17, and the fifth electrode 17. ) And the sixth electrode 18 are mainly focused and accelerated to pass through the shadow mask 3 provided on the inner surface of the fluorescent surface, and to collide with the fluorescent surface to emit light. At this time, the electron beam is concentrated through the main electrode portion of the electron gun and is centered. In order to scan the electron beam to the periphery, the deflection yoke 9 issues horizontal and vertical magnetic fields so that the electron beam 11 is deflected to the whole screen to screen the screen. It can be implemented. In a color cathode ray tube having a general inline electron gun, the red (R), green (G), and blue (B) three-color electron beams are arranged side by side horizontally, so that the deflection yoke 7 converges the electron beams in one place. For this purpose, self-convergence type using non-uniform magnetic field is applied.

2 shows a main lens of a conventional electron gun for color cathode ray tubes. The main lens is formed between the fifth electrode 17 and the sixth electrode 16, and opposing surfaces of the fifth electrode and the sixth electrode have rim structures 170 and 180. The auxiliary electrodes 171 and 181 are formed at a predetermined interval from the opposite surface. An elongated electron beam through hole is formed inside the auxiliary electrode, thereby increasing the main lens diameter. Further, a 'c' shaped correction electrode 21 is attached to the lower end of the shield cup 19 electrically connected to the sixth electrode 18. In addition, the electron beam through hole forming portion of the rim is rolled about 1 mm inside the electrode to minimize the change of pore size during electrode fabrication. The main lens finely adjusts the astigmatism characteristic, which is the difference between the horizontal and vertical focusing force of the electron beam, through the correction electrode located at the bottom of the shield cup while optimizing the action of the lens.

The electron beam is focused on the screen by the voltage of the fifth electrode 17 forming the main lens as described above. In this case, the focused state of the electron beam, that is, the size Dt of the final pixel on the screen may be expressed by the following equation. have.

In the above equation, Dx is the magnification of the main lens, Dst is the spherical aberration of the electron beam, and Dic is the magnification component of the electron beam due to the space charge repulsion effect.

In general, since voltage conditions, focal length, and the length of the electron gun are hardly changed, the influence of the spot diameter Dx due to the lens magnification in the above equation is not only low utilization as an electron gun design element, but also its effect is insignificant. In addition, the space charge repulsion force enlarges the spot diameter due to the repulsion and collision between the electrons in the electron beam. Therefore, in order to reduce the spot diameter (Dst) enlargement due to the space charge repulsion force, the angle of the electron beam propagation (hereinafter referred to as the divergence angle; α) It is advantageous to design large. On the other hand, the spherical aberration characteristic of the main lens is that the spot diameter (Dic) is enlarged due to the difference in focal length between the electrons passing through the paraxial axis of the lens and the electrons passing through the circular axis. The smaller the divergence angle α, the smaller the spot diameter on the screen. In particular, by reducing the spherical aberration while reducing the space charge repulsion, the magnification of the main lens reduces the spread of the spot due to spherical aberration even when an electron beam with a large divergence angle is incident, and also reduces the space charge repulsion after passing through the main lens. This enables small spots on the screen.

The change in the spot diameter according to the main lens diameter is shown in FIG. 3. As can be seen from the graph, the larger the main lens diameter, the smaller the enlargement of the spot diameter due to the spherical aberration of the main lens, so that the spot diameter on the screen can be reduced.

Recently, by improving the design technology of the electron gun and extending the life of the cathode, the electron beam passing hole of the first electrode is reduced to reduce the radiation area of the electron beam, thereby reducing the spot on the screen and improving the uniformity of the resolution across the screen. It is possible to achieve the desired resolution without applying Dynamic Focus, which has been applied to improve the resolution of the screen of the cathode ray tube of the large screen. When the resolution is improved by employing the dynamic focus, the resolution of the periphery of the screen is improved, but a circuit for driving the same is added to the chassis to act as a cost increase factor. Therefore, the static focus can be applied by reducing the electron beam through hole of the first electrode, thereby eliminating the dynamic focus circuit and lowering the cost. However, in the case of the electron gun employing dynamic focus, the astigmatism design is not considered much in the design of the main lens, whereas the design of the astigmatism is one of the most important parts when the static focus is applied. In order to improve the uniformity of resolution across the screen, it is very difficult to adjust the optimal state with one focus voltage because the focusing voltages in the horizontal and vertical directions at each point of the screen are different. In particular, when comparing the difference between the optimal focusing voltage of the center of the screen and the peripheral portion of the screen in the vertical direction, the vertical focusing voltage of the peripheral portion is higher than the center portion, and the larger the screen size, the larger the difference.

In general, if the horizontal and vertical design is optimally focused at the 1/4 point of the horizontal and vertical of the screen, the resolution can be uniformed across the screen. In addition, the optimum focusing voltage in the horizontal direction and the vertical direction at the quarter point above must match. Therefore, a difference between the horizontal optimal focusing voltage and the optimal focusing voltage at the center of the screen is generated. In general, the optimal focusing voltage at the screen center is lower than the horizontal optimal focusing voltage, and this difference is called astigmatism.

The astigmatism can be generated by adjusting the shape of the electron beam through hole of the auxiliary electrode forming the main lens of the electron gun or by changing the depth of the auxiliary electrode. However, when designing by changing the shape of the main lens, it is difficult to produce the same voltage ratio, OCV, and the like characteristics of the conventional main lens.

Accordingly, the present invention is to solve the above problems and to improve the resolution by making it easy to adjust the astigmatism by changing the thickness of the auxiliary electrode around the electron beam through hole located in the center without changing the shape of the electron beam through hole in the auxiliary electrode. The purpose is to provide an electron gun.

1 is a structural diagram of a typical cathode ray tube

2 is a partial cutaway perspective view and a sectional view showing a main electrode of a conventional electron gun;

3 is a view illustrating a screen spot mirror according to a main lens mirror;

4 is a partial cutaway perspective view and a sectional view showing a main electrode part of a conventional electron gun according to the present invention;

5a to 5c are views showing the shape of the auxiliary electrode according to the present invention

6 illustrates astigmatism according to depth differences of auxiliary electrodes.

*** Explanation of symbols for the main parts of the drawing ***

8 electron gun 17 fifth electrode

18: sixth electrode 151,161: auxiliary electrode

Technical means of the present invention for achieving the above object is a color cathode ray tube electron gun comprising a main electrode consisting of a focusing electrode and a positive electrode for focusing the electron beam emitted from the cathode toward the phosphor screen, the main electrode portion red (R) And an auxiliary electrode in which the electron beam passing holes of three colors (G) and blue (B) are arranged in line; The thickness around the electron beam through hole located at the center of the auxiliary electrode is partially different.

Hereinafter, embodiments of the present invention according to the above configuration will be described with reference to the accompanying drawings.

As shown in FIG. 4, the main lens used in the asymmetric large-diameter electron gun of the present invention includes a fifth electrode 17 and an auxiliary electrode 171 provided inside the fifth electrode, a sixth electrode 18 and the sixth electrode. It is formed by an auxiliary electrode 181 provided therein, and each of the auxiliary electrodes is formed in a plate shape and is positioned on a vertical plane in an electron beam traveling direction. In the auxiliary electrode 171 disposed in the fifth electrode, three electron beam through holes are formed, and an asymmetric slot 182 is formed around the central electron beam through hole. The asymmetric slot 182 means thirty different sizes of width and length, and an elongated slot is formed in FIG. 4.

That is, when the longitudinal slot 182 having a width narrower than the horizontal diameter of the electron beam through hole positioned at the center of the auxiliary electrode 171 is formed, the thickness Tb of the horizontal portion and the thickness of the vertical portion at the center of the electron beam through hole are formed. (Tv) is different.

In general, a focus voltage is applied to the fifth electrode and a high voltage is applied to the sixth electrode. Accordingly, the electrostatic lens is formed by the potential difference between the electrodes to which the respective voltages are applied, and the electrostatic lens serves to focus each electron beam bundle so that the optimally focused spot can be seen on the screen.

However, the auxiliary electrode is particularly sensitive to the main lens forming electrode and easily used for spot adjustment. When the vertical width of the electron beam through hole of the auxiliary electrode 171 provided in the fifth electrode is greater than the horizontal width or the position of the auxiliary electrode provided in the fifth electrode is far from the opening of the sixth electrode opposing surface, that is, In FIG. 4, as Dv increases, astigmatism decreases. Astigmatism according to the depth difference Dv-Dh of the auxiliary electrode is illustrated in FIG. 6.

The present invention is to adjust the astigmatism by using the position of the auxiliary electrode installed inside the fifth electrode, without changing the electron beam through hole size, the method of adjusting the position of the auxiliary electrode in Figures 5a, 5b As shown in the drawing, there is a method of thinning the thickness around the electron beam through hole of the auxiliary electrode and a method of protruding around the electron beam through hole toward the cathode while maintaining the same thickness of the auxiliary electrode as shown in FIG. 5C.

FIG. 5A shows an asymmetric slot having a thickness of the vertical portion around the electron beam through hole of the auxiliary electrode thinner than a horizontal portion, and FIG. 5B shows the same thickness around the electron beam through hole of the auxiliary electrode, but the electron beam through hole on both sides of the auxiliary electrode To form a thinner circular symmetrical slot, different from the surrounding thickness. In particular, the method illustrated in FIG. 5B is the only method capable of adjusting astigmatism in the auxiliary electrode in which the circular electron beam through hole is formed.

As described above, the astigmatism can be enhanced to a maximum of 500V by forging or forming a stage on the opposite surface of the opening of the auxiliary electrode to vary the depth of the auxiliary electrode in the vertical direction and the horizontal direction. In particular, the present invention is the only method that can control astigmatism when applying a circular electron beam through hole.

As described above, the present invention provides astigmatism by up to 500V by varying the depth of the auxiliary electrode in the vertical direction and the horizontal direction by forging or forming a stage on the surface around the electron beam through hole of the auxiliary electrode forming the main lens. You can strengthen it. In addition, since the present invention does not change the electron beam through hole shape of the conventional auxiliary electrode, not only the design time may be shortened but also the development period may be shortened.

Claims (10)

In the electron gun for a color cathode ray tube comprising a main electrode portion consisting of a focusing electrode and an anode focusing the electron beam emitted from the cathode toward the phosphor screen, The main electrode part has an auxiliary electrode in which electron beam through holes of three colors (R), green (G), and blue (B) are arranged inline; Electron gun for color cathode ray tube, characterized in that the thickness around the electron beam through hole located in the center of the auxiliary electrode is partially different. The method of claim 1, The electron gun for the color cathode ray tube, characterized in that the vertical length and the horizontal length of the electron beam passing hole is the same. The method of claim 1, An electron gun for a color cathode ray tube, characterized in that the thickness of the vertical portion around the electron beam through hole located at the center of the auxiliary electrode is thinner than the thickness of the horizontal portion. In the electron gun for a color cathode ray tube comprising a main electrode portion consisting of a focusing electrode and an anode focusing the electron beam emitted from the cathode toward the phosphor screen, The main electrode part has an auxiliary electrode in which electron beam through holes of three colors (R), green (G), and blue (B) are arranged inline; And the thickness of the portion surrounding the electron beam through hole positioned at the center of the auxiliary electrode is different from the thickness around the electron beam through hole located at both sides of the auxiliary electrode. The method of claim 4, wherein The electron gun for the color cathode ray tube, characterized in that the vertical length and the horizontal length of the electron beam passing hole is the same. The method of claim 4, wherein An electron gun for a color cathode ray tube, characterized in that the thickness around the electron beam through hole located in the center of the auxiliary electrode is thinner than the thickness around the electron beam through hole located on both sides of the auxiliary electrode. The method of claim 4, wherein And a thickness of a portion surrounding the electron beam through hole located at the center of the auxiliary electrode is thinner than the thickness of the auxiliary electrode. The method of claim 7, wherein The electron gun for a color cathode ray tube, characterized in that the portion surrounding the electron beam through hole located in the center of the auxiliary electrode is circular. In the electron gun for a color cathode ray tube comprising a main electrode portion consisting of a focusing electrode and an anode focusing the electron beam emitted from the cathode toward the phosphor screen, The main electrode part has an auxiliary electrode in which electron beam through holes of three colors (R), green (G), and blue (B) are arranged; The electron gun for a color cathode ray tube, characterized in that the periphery of the electron beam through hole located in the center of the auxiliary electrode protrudes toward the cathode. The method of claim 9, The electron gun for the color cathode ray tube, characterized in that the vertical length and the horizontal length of the electron beam passing hole is the same.