KR100442299B1 - Gun for Color Cathode Ray Tube - Google Patents

Abstract

It is an object of the present invention to provide an electron gun for a color cathode ray tube which minimizes deflection aberration of an electron beam by improving an electrode shape of an electron gun and improves resolution.

Accordingly, the present invention has a three-pole portion consisting of a plurality of cathodes for emitting an electron beam, a first electrode that is a control electrode for controlling the radiation amount of the electron beam, a second electrode for accelerating to the screen, and serves to focus the electron beam a certain amount At least two electrodes, i.e., a prefocus lens unit consisting of at least three electrodes, a fourth electrode, and a fifth electrode, and an electrode forming a main lens for focusing the electron beam on the screen are two electrodes, i. In the electron gun composed of an electrode and an anode electrode, the first electrode has a vertical slot longer than the horizontal length is recessed to a predetermined depth into the second electrode side electrode, the electron beam passing hole is formed in the center thereof, The second electrode is provided with a horizontal slot having a width longer than the length of the second electrode which is recessed to a predetermined depth inside the first electrode, and an electron beam passing hole is formed at the center thereof. The third electrode facing the second electrode is a combination of a circular hole and a square hole, wherein the square hole is an elongated rectangular hole, and a circular hole having a diameter larger than the horizontal width of the elongated rectangular hole and smaller than the vertical width is combined at the center thereof. It provides a color cathode ray tube electron gun, characterized in that it has an elongated keyhole shape.

Description

Gun for Color Cathode Ray Tube

The present invention relates to an electron gun for a color cathode ray tube, and more particularly, to an electrode for forming an asymmetric shear focusing lens in an electron gun.

The electrodes of the inline electron gun of the cathode ray tube are positioned at regular intervals to be perpendicular to the path through which the electron beam passes so that the electron beam generated from the cathode can be controlled in a constant intensity to reach the screen.

Hereinafter, the configuration of a general color cathode ray tube electron gun through FIGS. 1 and 2 will be described in detail.

As shown in FIG. 1, a common grid of three mutually independent cathodes 1, three cathodes 1 disposed at a predetermined distance from the cathode 1, and a first electrode 2, and the first electrode ( The second electrode 3, the third electrode 4, the fourth electrode 5, the fifth electrode 6, and the sixth electrode, also referred to as the anode electrode 7, arranged at regular intervals in 2) It is.

The BSC 9 which serves to fix the electron gun 10 to the neck portion 22 of the funnel 20 while electrically connecting the electron gun 10 and the funnel 20 to the upper portion of the sixth electrode 7 is provided. The attached shield cup 8 is installed.

When power is applied to the heater 1a embedded in the cathode 1 of the electron gun 10, electrons are emitted from the cathode surface, and the electrons 11 are controlled by the first electrode 2, which is a control electrode. The electron beam 11 is accelerated by the second electrode 3, which is an acceleration electrode, and is formed between the second electrode 3, the third electrode 4, the fourth electrode 5, and the fifth electrode 6. The electron beam is partially focused and accelerated by the shear focusing lens, and mainly focused and accelerated by the fifth electrode 6, also called a focus electrode, which is a main lens forming electrode, and the sixth electrode 7, also called an anode electrode.

As described above, the electron beam 11 passing through the electron gun 10 passes through the shadow mask 30 installed on the inner surface of the screen 40 and impinges on the fluorescent surface to implement a screen through light emission. In order for the electron beam passing through the electron gun 10 to hit the entire screen, a means for deflecting the electron beam is required. A deflection yoke 24 is provided outside the electron gun 10 so that the electron beam 11 is moved to the entire screen. Deflect

2 is an exploded perspective view of a general electron gun.

Referring to the drawings, generally, the voltage applied to the second electrode 3 is about 400 to 1,000 V, and the voltage applied to the third electrode 4, which is the focusing electrode, is about 6000 to 10000 V, and the sixth electrode is the anode electrode. The voltage applied to (7) is about 20 ~ 35KV. In addition, the fifth electrode 6 and the anode electrode 7 forming the main lens have a common opening through which three electron beams pass, and the electrostatic field control electrode bodies 62 and 72 provided in a plate shape with a predetermined distance from the opening. Is built in.

3A, 3B, and 3C are plan views showing electron beam through holes of the first electrode 2, the second electrode 3, and the third electrode 4 of the conventional electron gun.

FIG. 3A shows a plan view of the first electrode 3, in which the first electrode 2 facing the second electrode 3 is recessed to a predetermined depth in the electrode and is longer than the width of the longitudinal slot 2a. The electron beam through hole (2aa) of the square is formed in the center of the, and as shown in Figure 3b the second electrode (3) facing the first electrode (2) is longer than the horizontal length that is recessed in the electrode to a certain depth The elongated slot 3a is provided and the electron beam through-hole 3aa is formed in the center. As shown in FIG. 3C, the electron beam through hole 4aa of the third electrode 4 facing the second electrode 3 is formed of a circular hole.

The electron beam 11 should be deflected to the entire screen area. In the color receiving tube using an inline type electron gun, three electron beams of red, green, and blue are arranged side by side horizontally, so that each electron beam is nonuniform to converge to one of the fluorescent surfaces. Self-convergence deflection yoke using magnetic field is applied. Looking at the distribution of the magnetic field generated in the deflection yoke to which the self-focus type is applied, the horizontal deflection magnetic field is pincushioned and the vertical deflection magnetic field is barrel-shaped so that the deviation of concentration at the periphery of the fluorescent surface is corrected.

The 4-pole component of the deflection magnetic field focuses the electron beam in the vertical direction and diverges in the horizontal direction, so that the vertical beam is focused at a shorter distance than the horizontal beam, and the vertical direction of the beam bulges on the screen. It causes a halo phenomenon, resulting in deterioration of image quality. As the deflection magnetic field is not applied at the center of the screen, the electron beam spot has an accurate phenomenon, but as described above, the high-density horizontal core that is dissipated in the horizontal direction and overconcentrated and distorted in the vertical direction, and the upper and lower parts of the high density are distorted. Halo, which is an area, is generated, which results in deterioration of resolution, especially in the periphery of the screen. That is, in the case of the deflection yoke adopting the non-uniform magnetic field, it is natural that the distortion of the beam spot occurs around the screen.

In addition, the problem becomes larger as the water tube is larger, or the larger the angle of deflection, and must be solved when considering the tendency of consumers who prefer a large water tube and increasing the deflection angle according to the size of the water tube. It is one of the tasks. In order to solve the above problems, the four-pole component is generated by the electron gun to cancel the four-pole component generated in the self-focused deflection yoke, so that the electron beam components in the horizontal and vertical directions can be focused at one point at the same time. That is, in order to form a four-pole lens, the focusing electrode is divided into two first focusing electrodes and a second focusing electrode, and a dynamic 4-pole electrode is provided between the electrodes to generate a potential difference between the 4-pole electrodes to form a 4-pole lens. Thus, astigmatism can be corrected. In addition, the electron beam is focused in front of the screen by the difference in the electron beam moving distance between the center and the peripheral portion of the screen, and the halo phenomenon still occurs. Therefore, in order to solve the above problem, when the electron beam is deflected to the periphery of the screen, a dynamic voltage synchronized with the deflection frequency is applied to weaken the power of the main lens to adjust the focusing distance of the beam, thereby correcting the astigmatism of the electrostatic lens. The method is mainly adopted.

4 illustrates a beam spot in which the halo phenomenon generated around the screen is corrected by the dynamic quadrupole lens. Looking at the beam spot 11a shown on the outside of the screen, the halo in the vertical direction is still removed, but is excessively focused, resulting in a deterioration of the horizontal and vertical beam aspect ratios. In addition, there is a problem that moiré occurs on the periphery of the screen because it not only causes resolution degradation in the horizontal direction of the periphery but also increases the brightness ratio between the light and dark portions in the moire contrast-moire pattern.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an electron gun for a color cathode ray tube which minimizes deflection aberration of an electron beam by improving an electrode shape of an electron gun and improves resolution.

1 is a schematic cross-sectional view showing a colored cathode ray tube equipped with a conventional electron gun;

2 is an exploded cross-sectional view illustrating each electrode of the electron gun.

3A, 3B, and 3C are plan views illustrating a first electrode, a second electrode, and a third electrode, respectively.

4 is a plan view showing the shape of an electron beam spot implemented on a screen by a conventional electron gun;

5A, 5B, and 5C are plan views showing a first electrode, a second electrode, and a third electrode of the electron gun according to the present invention, respectively.

FIG. 6A is a graph showing the ratio of the horizontal divergence angle to the vertical divergence angle of the outermost electron beam at a point moved from the third electrode toward the screen at a distance; FIG.

6B is a graph showing the product of the divergence angle of the electron beam multiplied by the size of the dot;

Figure 7 is a plan view showing the shape of the electron beam spot implemented on the screen by the present invention.

** Explanation of symbols for main parts of drawings **

1: cathode 2: first electrode

3: second electrode 4: third electrode

5: fourth electrode 6: fifth electrode

7: anode electrode, sixth electrode 2a: longitudinal slot

3a: horizontal slot 2aa, 3aa, 4aa: electron beam through hole

42: longitudinal keyhole

In order to achieve the above object, the present invention provides a three-pole portion including a plurality of cathodes emitting an electron beam, a first electrode serving as a control electrode for controlling the radiation amount of the electron beam, a second electrode for accelerating to a screen, and focusing the electron beam a predetermined amount. At least two electrodes that serve to make a portion, that is, a prefocus lens unit consisting of a third electrode, a fourth electrode, and a fifth electrode, and two electrodes forming an main lens for focusing the electron beam on the screen That is, in the electron gun composed of the fifth electrode and the anode electrode,

The first electrode has an elongated slot having a length longer than that of a width which is recessed to a predetermined depth in the second electrode side electrode, and an electron beam through hole is formed at the center thereof, and the second electrode is formed inside the first electrode side electrode. It is provided with a horizontal slot longer than a vertically recessed depth, and an electron beam through hole is formed at the center thereof. The third electrode facing the second electrode is a combination of a circular hole and a square hole, and the square hole has an elongated rectangular shape. A color cathode ray tube electron gun is characterized in that it has an elongated keyhole shape in which a circular hole having a diameter larger than the horizontal width of the elongate rectangular hole and smaller than the vertical width is combined at the center thereof.

Hereinafter, the configuration of the present invention will be described in more detail with reference to the accompanying drawings. For reference, prior art description of the present invention will refer to the same reference numerals as they are for the parts consistent with the prior art in order to avoid duplication of description.

5A, 5B, and 5C are views showing preferred embodiments of the first electrode, the second electrode, and the third electrode in the electron gun for color cathode ray tube according to the present invention.

Referring to FIG. 5A, the first electrode 2 is formed with an elongated slot 2a longer than the width of the second electrode 3 which is recessed to a predetermined depth. A rectangular hole 2aa is formed in the center of the slot 2a, and the electron beam passes through the hole.

FIG. 4B is a view showing a slot 3a formed in the second electrode 3 and an electron beam passing hole 3aa. The horizontal slot having a length longer than the vertical slot 3a recessed to a predetermined depth inside the first electrode side is shown in FIG. A rectangular electron beam through hole 3aa is formed in the center.

FIG. 4C shows the third electrode 4, in which an electron beam through hole 42 having a substantially key hole shape is shown. The electron beam through hole 42 has a substantially long shape, and a circular hole 42b having a diameter larger than the horizontal width and smaller than the vertical width overlaps the center of the vertical rectangular hole 42a.

Longitudinal slot 2a in the first electrode 2 facing the second electrode 3, and horizontal slot 3a in the second electrode 3 facing the first electrode 2 When the electron beam 11 is formed into a horizontal beam having a length longer than the vertical angle, the electron beam is formed into a horizontal beam having a length longer than the vertical angle, thereby receiving less deflection aberration when the electron beam is deflected to the periphery. In this way, the distortion of the electron beam aspect ratio at the periphery of the screen can be prevented.

In addition, in the present invention, the electron beam through hole 42 of the third electrode 4 facing the second electrode 3 is formed in the form of an elongated key hole, similarly to the first electrode 2 and the second electrode 3. It acts to lateralize the electron beam.

In more detail, by forming a strong asymmetric lens having a short distance in the horizontal direction than a short distance in the vertical direction, the electron beam is formed into the above-mentioned electron beam. Therefore, the action of the longitudinal keyhole of the third electrode 4 opposed to the second electrode 3 is an asymmetric tripolar portion composed of only the longitudinal slot 2a of the first electrode and the horizontal slot 3a of the second electrode. Since a stronger horizontalization action can be applied to the horizontal beam formed by the lens, the deflection aberration at the periphery of the screen can be sufficiently reduced.

As a result, since the vertical electron beam spot can be enlarged at the periphery of the screen, the moiré contrast can be reduced. In general, since the moiré contrast and the resolution are inversely related to each other, that is, when the moiré contrast is reduced, the resolution deteriorates, the moiré contrast should be reduced within the range where the target resolution does not deteriorate.

Example

As an embodiment of the present invention, the following results were obtained by applying the technique of the present invention to a 28-inch color cathode ray gun electron gun. 6A and 6B show a computer analysis result of applying the above-described technique of the present invention, and FIG. 6A shows the outermost electron beam at a point moved from the third electrode 4 toward the screen at a certain distance without a influence of an external electric field. Is a graph showing the ratio of the horizontal divergence angle to the vertical divergence angle of FIG. 6B is a graph showing a value obtained by multiplying the divergence angle by the dot size (hereinafter, referred to as an emitter).

In more detail, the slot depth d1 to the first electrode thickness G1t, that is, the slot depth d1 is added to the electron beam through hole thickness t1 in FIG. 5A to be referred to as the first electrode thickness G1t. In this case, the ratio g1 = d1 / G1t, and the ratio of the slot depth d2 to the second electrode thickness G2t, that is, the electron beam through hole thickness t2 and the slot depth d2 in FIG. The ratio g2 = d2 / G2t when the thickness of the two electrodes (G2t), and the aspect ratio of the G3 longitudinal keyhole, that is, the ratio g3 = G3v / G3h when the horizontal width of the square hole is G3h and the vertical width is G3v in FIG. It is decided.

In general, the smaller the emitter, the smaller the electron beam spot is formed on the screen. As shown in FIGS. 6A and 6B, the emitter ratio is set as small as possible while setting the horizontal / vertical divergence angle as large as possible to satisfy the target resolution. Moiré contrast can be reduced to prevent moiré.

The above relationship can be expressed by the following equation.

When the ratio of the horizontal / vertical divergence angle of the electron beam is Rt and the emitter is Em,

Rt = 0.943 + 0.223g1 + 0.149g2 + 0.087g3

Em = 0.134 + 0.134g1-0.101g2 + 0.00383g3.

From the above two relations, it is possible to obtain an area capable of reducing moiré contrast while satisfying the target resolution. It is preferable that the following is satisfied in the 28 "color cathode ray tube by applying this.

0.3≤0.223g1 + 0.149g2 + 0.089g3 ≤0.6

7 is a schematic diagram showing a state in which the beam spot of the screen periphery is improved by the present invention.

Compared with the related art of FIG. 4, the beam spot 11b of the periphery of the screen is larger in the vertical direction, while smaller in the horizontal direction, thereby improving the aspect ratio of the beam spot. In fact, as described above, the target resolution can be sufficiently realized while preventing moiré as a result of conducting the electron gun for the 28 "color cathode ray tube.

In order to prevent the deterioration of the electron beam spot, that is, the resolution and the quality of the moiré, the deflection force toward the periphery of the screen is increased, so that the tripolar lens is composed of an asymmetric lens so that the deflection aberration due to the non-uniform deflection magnetic field caused by the deflection yoke By minimizing this, peripheral resolution and moiré can be improved.

Claims (2)

A third electrode comprising a plurality of cathodes emitting an electron beam, a first electrode serving as a control electrode for controlling the radiation amount of the electron beam, a second electrode for accelerating to a screen, a third electrode serving to focus the electron beam a predetermined amount, and In the electron gun consisting of a prefocus lens unit consisting of a four-electrode, a fifth electrode, and a fifth electrode and an anode electrode forming a main lens for focusing the electron beam on the screen, The first electrode has an elongated slot longer than the width of the first electrode, the electron beam passing hole being formed in the center thereof; The second electrode has a horizontally longer slot than a vertical length recessed to a predetermined depth in the first electrode side electrode, and an electron beam through hole is formed at the center thereof; The third electrode facing the second electrode is a combination of a circular hole and a square hole, wherein the square hole is an elongated rectangular hole, and a circular hole having a diameter larger than the horizontal width of the elongated rectangular hole and smaller than the vertical width is combined at the center thereof. Has an elongated keyhole shape; The ratio of the depth of depression of the slot to the thickness of the first electrode is g1, the ratio of the depth of depression of the slot to the thickness of the second electrode is g2, and the square length of the third electrode electron beam passing hole facing the second electrode. An electron gun for a color cathode ray tube, wherein the ratio of the square width to the width satisfies the following relation. 0.3≤0.223g1 + 0.149g2 + 0.089g3 ≤0.6 delete