KR20000051932A - electron gun of CRT - Google Patents

Abstract

PURPOSE: An electron gun for a color cathode ray tube is provided to improve resolution in a peripheral portion of a screen by having electron beam radiated from a main lens part have a focusing power. CONSTITUTION: An electron gun for a color cathode ray tube comprises a plurality of emitting units, a three-electrode unit, a plurality of focusing electrodes(11) and anodes(12), an electric field correcting unit, and an inner electrode(100). The plurality of emitting units emit electron beam. The three-electrode unit is composed of a control electrode and an accelerating electrode to control an emission quantity and a crossover of the electron beam. The plurality of focusing electrodes and anodes are positioned in line to form a main lens for focusing the electron beam to a screen. The electric field correcting unit is positioned in a position receded a predetermined distance from a rim part on a corresponding surface to the electrodes for forming the main lens. The inner electrode has central and side beam passing holes(100a,100b), established inside an electrode for applying a static voltage among the plurality of focusing electrodes. In the central and side beam passing hole of the inner electrode, the width of the hole becomes narrower in upper/lower portions than in a center portion of the hole, so that the electron beam receives a strong focusing power in a diagonal direction before being radiated to a focusing electrode part for applying a static voltage.

Description

Electron gun of CRT

The present invention relates to an electron gun that is applied to a color cathode ray tube and the like to emit an electron beam for emitting a fluorescent film, and more particularly, to an electrode structure of an electron gun composed of a plurality of inline electrodes to emit and control an electron beam in a cathode ray tube. It is about.

In general, a color-brown tube emits a desired phosphor by hitting a fluorescent surface while the electron beam emitted from the electron gun is deflected to the whole screen and proceeds at a constant speed. The electron gun emitting electron beam emits a cathode and an electron beam. It consists of several cylindrical electrodes for focusing on the fluorescent surface while accelerating at high speed.

The apparatus shown in FIG. 1 will be described as an example of a color brown tube according to the prior art.

Looking at the overall configuration, the panel 1 mounted on the front side of the CRT, the fluorescent surface 2 on which red (R), green (G) and blue (B) phosphors are applied on the inner surface of the panel 1, and the fluorescent surface A shadow mask 4 having a color discrimination function of the electron beam 3 incident to the light beam 2, a funnel 5 coupled to the rear surface of the panel 1 to keep the interior in a vacuum state, and A tubular neck portion 5a that is retracted to the rear, an electron gun 6 mounted inside the neck portion 5a to emit the electron beam 3, and an electron beam 3 surrounding the outer side of the funnel 5. It is made of a deflection yoke (7) to deflect.

FIG. 2 shows an electrode arrangement state of the electron gun 6 mounted in the neck portion 5a, and is largely comprised of a triode portion and a main lens portion.

The three poles include three cathodes 8 arranged side by side horizontally independently of each other with a built-in heater, control electrodes 9 arranged to be maintained at a predetermined interval on the cathode 8 to control and accelerate heat electrons radiated from the cathode; It consists of the accelerating electrode 10.

The main lens unit is composed of a focusing electrode 11 and an anode 12 for focusing and finally accelerating the electron beam 3 generated in the triode. In the above, the control electrode 9 is grounded, a high voltage of 500 to 1000 V is applied to the acceleration electrode 10, 25 to 35 KV is applied to the anode 12, and 20 to 30% of the anode voltage is applied to the focusing electrode 11. An intermediate voltage is applied.

The color gun tube electron gun configured as described above has an electrostatic lens formed by a voltage difference between the focusing electrode 11 and the anode 12, in particular, as a predetermined potential is applied to each electrode. The emitted electrons are focused at the center of the screen while accelerating and focusing toward the panel. At this time, the deflection yoke attached to the funnel 5 acts to deflect the electron beam focused at the center of the screen to the entire area of the screen. In a color receiver tube using an in-line electron gun, since three electron beams of red, green, and blue are arranged side by side horizontally, the deflection yoke (7) is non-uniform in order to converge the three electron beams on one side of the fluorescent surface (2). Self-convergence using uniform magnetic field is applied.

The focusing electrode 11 and the anode 12 are main lens forming electrodes, and a shield cup 14, which is a shielding electrode for shielding and weakening the leakage magnetic field of the deflection yoke, is formed on the electrode furthest from the cathode.

US Pat. No. 5,512,797 shown in FIG. 3 is an example of a conventional main lens forming electrode, and will be described in more detail.

That is, FIG. 3 is a form in which the main lens is formed by the potential difference between the focusing electrode 11 and the anode 12. The aperture diameter of the main lens is increased to reduce spherical aberration generated in the main lens. It is a technique that can be reduced, which is commonly referred to as "large-diameter principal lens technology".

This large-diameter main lens technique is described by the following formula.

The increase in the spot diameter due to the spherical aberration is proportional to 1 / (ΔR) ³ .

That is, the spherical aberration is inversely proportional to the lens diameter ΔR ³ , and as the lens diameter increases, the spherical aberration rapidly decreases.

The operation of the large-diameter lens is formed by forming rims 17b and 18b on opposite surfaces to increase the aperture of the main lens formed between the focusing electrode 11 and the anode 12, and the electron beam passing holes common to the three electron beams. By forming (11a, 12a), the corresponding lens intensity difference is shown for each electron beam between the center of the lens and the outside of the lens.

In order to compensate for the lens strength, the electrostatic field control electrodes 15 and 16 are fixed at a point where the electron beam passing holes 11a and 12a are retracted at a predetermined interval to form the same intensity of the lens corresponding to the three electron beams.

The electrostatic field control electrodes 15 and 16 are bent in the form of "??" and both ends of the electrode plates 17 and 18 having the electron beam passing holes 17a and 18a through which the central electron beam passes, and the electrode plates 17 and 18a formed as square holes. Consists of two blades (19, 20) formed by, the thickness of the raw material is to use a plate of about 0.5mm ~ 0.6mm in consideration of the bending work.

The electrostatic field control electrodes 15 and 16 of the conventional electron gun have rectangular central holes 17a and 18a and blades 19 and 20 on both sides. The outer electron beam has an electrostatic field controlled by the blade.

The above-mentioned blades 19 and 20 are straight, and thus the most important factors to consider in the design of the large-diameter lens described above are how optimally the shape of the electrostatic field control electrodes 15, 16 and The structure is resistant to deformation, and also has a structure capable of growing a lens mirror.

However, in the case of the conventional electron gun, the center holes 17a and 18a of the electrode plate have a rectangular shape, and the outer electron beam through holes 11b and 12b are formed in the same manner as the straight portion and the circular portion, so that the electron beam is shown in FIG. As described above, in the case of the central hole 4a, a star-shaped pixel is formed around the core, and the pixels of the outer electron beam 4b appear in a fan shape around the core. This phenomenon occurs when the electron beam is deflected to the peripheral area of the screen.

In particular, since the defocusing phenomenon due to the distance difference and the defocusing phenomenon due to the deflection yoke occurs in the peripheral part of the screen, the same focusing voltage as the center part of the screen is not applied. Therefore, as described above, the central electron beam appears as a star in the periphery of the screen, and the outer electron beam appears as a fan shape, and this phenomenon has a problem of causing the resolution deterioration in the periphery of the screen.

The present invention is invented to solve the problems of the prior art as described above to improve the deterioration of the focusing force of the electron beam generated by the main lens when the electron beam emitted from the main lens is deflected to the periphery of the screen to improve resolution degradation at the periphery The purpose is to prevent it.

1 is a cross-sectional view showing a schematic configuration of a general color cathode ray tube.

2 is a schematic view showing the configuration of a conventional electron gun.

Figure 3 is a perspective view showing a part of the conventional large-diameter lens cut out.

4 is an electron beam pixel shape diagram in the periphery of a screen due to a conventional focusing voltage drop.

5A is a schematic cross-sectional view of a large-diameter lens unit according to the present invention;

Figure 5 (b) is an enlarged perspective view of the inner electrode according to the present invention.

FIG. 6A is a distribution chart of focusing force in the main lens due to the electrostatic field control electrode. FIG.

7 is an electron beam pixel shape diagram in the periphery of a screen according to the present invention;

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

11: focusing electrode, 11a: 1st focusing electrode, 11b: 2nd focusing electrode, 12: anode

15,16: electrostatic field control electrode, 100: inner electrode, 100a: center beam through hole

100b: side beam through hole

According to an aspect of the present invention for achieving the above object, a three-pole portion consisting of a plurality of electron beam emitting means for emitting an electron beam, a control electrode and an acceleration electrode for adjusting the radiation amount and crossover of the electron beam, and the electron beam Electric field correction means constituted by a plurality of focusing electrodes and anodes positioned inline to form a main lens for focusing on the screen, and a position retracted a predetermined distance from the rim formed on the mutually opposing surfaces of the main lens forming electrodes (electrostatic And a inner electrode having three electron beam through holes in a focusing electrode to which a constant voltage is applied, among the plurality of focusing electrodes, wherein the electron beam passes through the inner beam of the inner electrode. Up / down from the center of the ball to receive a strong focusing force in the diagonal direction before entering the application electrode With increasingly characterized by constituted by any shape that gradually decreases in width.

Preferably, the center beam through hole of the inner electrode has a rhombus shape symmetrical with respect to the center axis, and the side beam through hole has a pentagonal shape having an inclined portion toward the central electron beam through hole.

Preferably, the central beam through hole and the side beam through hole is characterized in that it is made in the longitudinal shape.

In this case, it can be seen that the strong focusing force can be applied to the diagonal direction of the pixel, which is a region in which the focusing force of the electron beam falls in the main lens due to the shape change of the electron beam through hole of the inner electrode.

As a result, there is an advantage that the pixel degradation in the periphery of the screen can be improved and the overall resolution of the color cathode ray tube can be improved.

And, there may be a plurality of embodiments of the present invention, hereinafter will be described in detail with respect to the most preferred embodiment.

Through this preferred embodiment, it is possible to better understand the objects, features and effects of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the device according to the present invention.

In addition, in drawing used for description, about the component similar to the prior art, the same code | symbol is attached | subjected, and the overlapping description may be abbreviate | omitted.

In the electron gun structure according to the present exemplary embodiment, the inner electrode 100 may be formed to assist the main lens, and as shown in (a) of FIG. 5, the focal point is formed to face the anode 12 to form the main lens. The electrode 11 is divided into two first focusing electrodes 11a to which a constant voltage is applied and two second focusing electrodes 11b to which a dynamic voltage is applied, and the anode 12 and the second focusing electrode 11b are fixed at the rim. Electrostatic field control electrodes 15 and 16 opposed to each other are formed at the retreat positions, and inner electrodes 100 having three electron beam through holes 100a and 100b are inserted into the first focusing electrode 11a, respectively. .

As shown in (b) of FIG. 5, the central electron beam through hole 100a of the inner electrode 100 has a rhombus shape having a vertical diameter of 6 mm and a horizontal diameter of 4 mm so that the focusing voltage increases in a diagonal direction with respect to the electron beam. The side beam passing holes 100b positioned at both side surfaces of the central electron beam passing hole 100a are formed with only an inner side surface as an inclined surface.

6 shows the focusing voltage generated in the main lens due to the quadrangular shape of the electrostatic field control electrode 15. In the figure, a phenomenon in which the focusing voltage decreases around 30 to 70 ° can be seen, which is represented by a star-shaped pixel as in the prior art.

In order to improve this, the inner electrode 100 according to the embodiment of the present invention has the astigmatism to be "+" (overfocus), and the electron beam through holes 100a and 100b are formed to act in a direction that favors pixel characteristics. The vertical was composed of an elongate shape about 3/2 larger than the horizontal.

As such, when the central electron beam through hole 100a of the inner electrode 100 is formed in a rhombus shape, a strong focusing action occurs in a diagonal region, and as a result, the diagonal direction 30 of the electrostatic field control electrode 15 shown in FIG. It acts in the direction to cancel the focusing force weakening component which generate | occur | produces in a -70 degrees) area | region.

In the case of the side beam through hole (100b), the conventional fan-shaped pixel is formed by the effect of the track shape of the rims (17b, 18b) of the focusing electrode opposing surfaces forming the main lens (4a) and the electrostatic field control electrode. This phenomenon occurs due to the straight portion on the outer electron beam passing hole of the inner side (4b). The outer electron beam through hole of the inner electrode 100 has a rhombic shape in the center hole, which is the inner part, and the outer part is formed in a straight shape. To improve.

That is, the inner electrode 100 having the electron beam through hole shape according to the present invention functions as a convex lens having a focusing effect, which is a direction for improving divergence generated near the diagonal direction of the electrostatic field control electrode 15. . As a result, as shown in FIG. 7, the electron beam pixel at the periphery of the screen is circularized around the core to reduce the focusing power weakening component generated in the main lens.

On the other hand, as a comparative example, conventionally, the focusing force is weakened in the diagonal direction in the electrostatic field control electrode 15 so that the central electron beam appears in the shape of a star and the outer electron beam appears in the shape of a fan, resulting in deterioration of pixels. According to the present invention, the deterioration of the focusing force in the diagonal direction can be improved to improve the resolution deterioration in the peripheral portion of the screen.

In addition, although specific embodiments of the present invention have been described and illustrated above, it is obvious that the present invention may be variously modified and implemented by those skilled in the art.

Such modified embodiments should not be individually understood from the technical spirit or the prospect of the present invention, and such modified embodiments should fall within the appended claims of the present invention.

As described above, the electron gun structure of the present invention has an effect of improving the resolution at the periphery of the screen by improving the focusing power weakening component generated for the electron beam emitted from the main lens to have a strong focusing power.

Claims (5)

Positioned inline to form a plurality of electron beam radiating means for radiating an electron beam, a tripole portion comprising a control electrode and an acceleration electrode for adjusting the radiation amount and crossover of the electron beam, and a main lens for focusing the electron beam on a screen A plurality of focusing electrodes and anodes, an electric field compensating means configured to retreat a predetermined distance from a rim formed on an opposing surface of each of the main lens forming electrodes, and a position within an electrode for applying a constant voltage among the plurality of focusing electrodes In the electron gun for a color cathode ray tube including an inner electrode formed with a center and a side beam through hole, respectively: Center and side beam through holes of the inner electrode, An electron gun for a color cathode ray tube, characterized in that the width of the electron beam is gradually decreased from the center of the ball to the top / bottom so as to receive a strong focusing force in the diagonal direction before the electron beam is incident on the constant voltage applying focusing electrode part. The method of claim 1, An electron gun for a color cathode ray tube, characterized in that the central beam through hole of the inner electrode is formed in a rhombus shape symmetrical from left to right with respect to the central axis. The method of claim 1, The central beam through hole of the inner electrode has a rhombus shape, An electron gun for a color cathode ray tube, wherein the side beam through hole has a pentagonal shape having an inclined portion toward the center beam through hole. The method of claim 1, An electron gun for a color cathode ray tube, characterized in that the center beam through hole and the side beam through hole of the inner electrode are formed in an elongated shape. The method according to claim 1 or 3, An electron gun for a color cathode ray tube, wherein the side beam through hole of the inner electrode is formed in a straight line in the vertical direction.