KR0144266B1 - Electron gun for color cathode ray tube - Google Patents

Abstract

The present invention relates to an electron barrel for a color cathode ray tube, so that the resolution at the periphery of the screen can be improved by eliminating astigmatism without using a separate correction electrode. To this end, the present invention provides an electron beam forming region composed of a cathode (1), first and second grid electrodes (2) and (3), and first and second substantially focusing three electron beams emitted from the electron beam forming region. Through holes 8 and 9 through which three electron beams pass through the first, second acceleration and focus electrodes 5 and 6 in an electron gun with an electrostatic focusing lens comprising acceleration and focus electrodes 5 and 6. ) And each of the upper rims 10 and 11 to be bent from the outer circumferential surface of each electrode to the through side, wherein the inclined portion 21 and the bottom surface in the first, second acceleration and focusing electrodes 5 are formed. Both sides of the part 22 are formed vertically, and the first inclined extension electrode 23 is formed by installing a first inclined extension electrode 23 having a central hole only in a bent surface with the inclined part 21 in the bottom part 22. One side of the 23 is fixed to be connected to the inward bending portion 18 in the upper rim 10 and the second inclination inside the second acceleration and focusing electrode 6. On the same plane of the head portion 25 of the extension electrode 24, the protrusions 25a are formed side by side in both directions, and the vertical inner diameter A of the protrusion 25a is the vertical inner diameter B of the upper rim 11. It is formed smaller and fixed to one side of the second inclined extension electrode 24 to be connected to the inward bent portion 19 of the upper rim (11).

Description

Electron gun for color cathode ray tube

1 is a front view showing a part of the conventional electron gun of a single electrostatic lens type cut out.

2 is a longitudinal cross-sectional view of an electron gun provided with a conventional gradient extension electrode.

Figure 3 is a perspective view showing a part of the main portion of FIG.

4 is a perspective view showing a conventional inclined extension electrode.

5 is a reference diagram showing the shape of an electron beam spot for each part in a conventional screen.

6 is a perspective view of a state in which a correction electrode is fixed to a conventional shield cup.

Figure 7 is a perspective view showing a part of the main portion of the electron gun to which an embodiment of the present invention is applied.

8 is a perspective view of a first inclined expansion electrode fixed in the first acceleration and focusing electrode of the present invention.

9 is a perspective view of a second inclined expansion electrode fixed in the second acceleration and focusing electrode of the present invention.

10 is a front view in a state in which the second inclined expansion electrode is fixed in the second acceleration and focusing electrode of the present invention.

11 is a cross-sectional view taken along the line A-A of FIG.

12 is a cross-sectional view taken along the line A-A of FIG. 10 showing another embodiment of the present invention.

Figure 13 is a schematic diagram for explaining the principle of removing the focusing force difference in the horizontal and vertical direction by the first, second inclined expansion electrode of the present invention.

14 is an enlarged view of a portion B of FIG.

FIG. 15 is a schematic diagram of a state in which a main lens is formed according to the presence or absence of first and second inclined extension electrodes.

(a) is a schematic diagram of a state in which the first and second inclined extension electrodes are installed.

(b) is a schematic diagram of a state in which the first and second inclined extension electrodes are not installed.

16 is a reference diagram showing the shape of the electron beam spot for each part in the screen of the present invention.

* Explanation of symbols for main parts of the drawings

5, 6: first and second acceleration and focusing electrodes 20, 25: head

21, 27: inclined portion 22, 26: bottom portion

23, 24: first and second inclined extension electrodes 10, 11: top

18, 19: inward bending portion 25a: protrusion

28: connection

The present invention relates to an electron barrel for a color cathode ray tube, and more particularly, to improve a resolution at a peripheral portion of a screen by eliminating astigmatism without using a separate correction electrode.

The conventional electron gun has a form similar to that of FIG. 1 and includes a cathode (1) that emits hot electrons according to electric signals of red (R), green (G), and blue (B) that are heated and input by a heater (H). ), A first grid electrode 2 installed at one side of the cathode to control an electron beam emitted from the cathode, and a second grid installed at one side of the first grid electrode to accelerate and draw hot electrons collected on the cathode surface; An electron beam forming region (BFG) is formed of the electrode 3, and one side of the second grid electrode is fixed to the third grid electrode 4 to narrow an electron beam that is subsequently incident from the electron beam forming region. The first acceleration and focusing electrodes 5 and the second acceleration and focusing electrodes 6 constituting a main focusing lens for focusing to form an electron beam spot are arranged in-line.

In addition, a shielding electrode (not shown) is fixed to the second acceleration and focusing electrode 6 to serve to shield and weaken the leakage magnetic field of the deflection yoke. On the other hand, depending on the type of electron gun, the third beam for focusing the electron beam forming region (BFR) constituting the electron beam forming region and the electrode constituting the electrostatic focusing lens to achieve a multi-stage focusing type to enhance the focusing effect A grid focusing lens system may be configured by further inserting a grid electrode and a fourth grid electrode.

A pair of bead glass (7) of each of the electrodes formed with three electron beam through-holes through which R, G, and B, respectively, generated in the cathode 1 pass, is fused and fixed at a predetermined interval to be integrated.

The conventional electron gun configured as described above is accelerated by the second grid electrode 3 while being controlled by pulling the electron beam by the first grid electrode 2 as the cathode 1 is heated by the heater to emit hot electrons. The difference between the voltage applied to the first acceleration and focusing electrode 5 and the second acceleration and focusing electrode 6 while passing through the first acceleration and focusing electrode 5 and the second acceleration and focusing electrode 6 which are lens systems. By condensing and accelerating finely by the light emitted by the phosphor applied to the inner surface of the panel to emit an image on the screen.

In the conventional electron gun, the electron beam passing holes from the first grid electrode 2 to the second acceleration and focusing electrode 6 are sequentially drilled in a state close to the source, so that the first acceleration and the focusing electrode 5 and the second acceleration are accelerated. And the electrostatic focusing lens formed by the focusing electrode 6 is also a lens having a circular axis symmetry, so that when the voltage required for the operation of the electron gun is applied to each electrode, the electron beam passing through the electron beam passing hole is refracted by Lagrange. In accordance with the law, the rotation is focused symmetrically.

Accordingly, when the circular electron beam leaving the electron gun reaches the center of the screen unaffected by the deflection yoke, the circular electron beam is narrowly focused to form a small circular electron beam spot.

That is, the electron beam emitted from the electron gun is scanned over the entire screen by the deflection magnetic field of the deflection yoke to reproduce the image.

The deflecting yoke of the deflection yoke should deflect the electron beam in the color cathode ray tube emitting a plurality of electron beams and concentrate the electron beams at a point on the screen, as described above. Adopts self-convergence method to achieve the purpose by emitting electron beam horizontally in-line and making the deflection magnetic field generated by the deflection yoke into non-uniform magnetic field with different magnetic field strength at the center and the edge (periphery of the screen) Doing. By the magnetic convergence magnetic field, the electron beams of R, G, and B are automatically concentrated in the whole screen.

The self-converging magnetic field is classified into a pin cushion magnetic field, which is a horizontal deflection magnetic field, and a barrel magnetic field, which is a vertical deflection magnetic field.

They are composed of two-pole and four-pole components, respectively, and are emitted from the electron gun, and then are mainly deflected by the two-pole components, and are also subjected to magnetic forces by the four-pole components, and diffuse magnetic field lenses in the horizontal direction and focus in the vertical direction. Under the action of the magnetic lens. Accordingly, as shown in FIG. 5, in the center of the screen without the influence of the deflection magnetic field, the focusing action is almost the same in the vertical direction and the horizontal direction, so that the electron beam forms a nearly circular electron beam spot.

However, in the periphery (edge) of the screen affected by the deflection magnetic field, the electron beam in the vertical section is strongly focused by the focused magnetic field lens in the vertical direction and overfocused, and the electron beam in the horizontal direction is focused on the diffuse magnetic field lens in the horizontal direction. This results in a halo phenomenon that is emitted and under focus, resulting in lower resolution. Accordingly, as described above, in order to improve the degradation of the resolution of the peripheral portion of the screen deteriorated by the deflection magnetic field, the technology as shown in FIGS. 2 to 4 (Patent No. 17,874) has been developed.

The structure forms through holes 8 and 9 so that three electron beams pass in common to the mutually opposite surfaces of the first and second acceleration and focusing electrodes 5 and 6, and bends toward the through side at the outer peripheral surface of each electrode. The inclined extension electrode 12 as shown in FIG. 4 was fixed to form upper rims 10 and 11 and to maintain a predetermined interval in the through holes 8 and 9.

The inclined extension electrode 12 has a head 13 for fixing in the first, second acceleration and focusing electrodes 5 and 6, and an inclined portion having a protruding piece 14a in a triangle shape on both upper and lower sides thereof. 14), the bottom portion 15 having a central hole 15a extending to the inclined portion, wherein the inclination angle θ of the inclined portion 14 and the bottom portion 15 is in the range of 100 to 140 degrees. .

The reason why the inclination angle from the head portion 13 to the bottom portion 15 is in the range of 100 to 140 ° is because the beam spot appears to be the smallest under the above conditions.

The reason why the central hole 15a formed in the inclined extension electrode 12 is extended to the inclined portion 14 is to minimize spherical aberration by reducing spherical aberration.

That is, in order to form an electric field smoothly.

In the electron gun employing the inclined extension electrode 12, the side beam and the center beam coincide at the center of the screen, i.e., in the dimensions of the inclined extension electrode satisfying the static convergence, the protrusions 14a of the inclined portion 14 Since the electric field of the side balls becomes asymmetrical in the horizontal and vertical directions, the astigmatism increases in the side balls. As shown in FIG. 5, the astigmatism, which is the difference in the focusing force in the horizontal direction and the vertical direction, has not been eliminated.

This is because a special correction means is necessary because the electric fields distributed in the center hole and the side hole of the focusing lens are basically different.

In addition, the production of the mold for forming the inclined extension electrode 12 is not only cumbersome, but also a cumbersome molding operation, resulting in a decrease in productivity.

As another technique for solving the above problems, as shown in FIG. 6, the correction electrode 17 having horizontal partition walls is welded and fixed above and below the electron beam through hole 16a formed in the shield cup 16. The technique of fixing the shield cup 16 on which the correction electrode 17 is fixed to the second acceleration and focusing electrode 6 is known.

This technique provides a sufficient shielding of the magnetic field generated by the deflection yoke when the electron beam emitted from the cathode passes through the interior of the second acceleration and focusing electrode 6. This has the advantage that it is possible to correct the score difference in the desired direction.

However, in the conventional technique, since the punching operation is performed to form the electron beam through hole during the processing of the shield cup 16 to which the correction electrode 17 is fixed, the flattening of the connection surface (a peripheral part of the electron beam through hole) to which the correction electrode is fixed And it is difficult to match the electron beam through hole formed in the shield cup and the correction electrode, the welding position of the correction electrode is wrong, and thus the movement path of the electron beam is changed, as well as the precision processing to match the upper and lower lengths of the correction electrode Since it becomes difficult, there is a problem of lowering the resolution.

The present invention has been made to solve such a problem in the prior art, so that the electron beam through hole is formed only as the height of the bottom portion formed in the first inclined extension electrode and extends to the side beam hole on both sides of the head of the second inclined extension electrode. It is an object of the present invention to form a protrusion so that the protrusion serves as the correction electrode without installing a separate correction electrode in the shield cup.

According to an embodiment of the present invention for achieving the above object, the first, second acceleration to substantially focus the electron beam forming region consisting of a cathode, the second, the second grid electrode and three electron beams emitted from the electron beam forming region And forming through-holes through which three electron beams pass through the first, second-acceleration and focusing electrodes, respectively, in an electron gun including a capacitive focusing lens including a focusing electrode, and forming an upper rim to be bent toward the through-side from the outer circumferential surface of each electrode. In this case, both sides of the inclined portion and the bottom portion are formed vertically in the first acceleration and focusing electrode, and the first inclined extension electrode having a bent surface with a bent surface but a central hole is formed inside the bottom portion. One side of the extension electrode is fixed to be connected to the inward bent portion of the upper rim, and inside the second acceleration and focusing electrode, the head of the second inclined extension electrode A collar formed by forming projections side by side in both directions on one plane and forming a vertical inner diameter of the protrusion smaller than a vertical inner diameter of the upper rim so that one side of the second inclined extension electrode is connected to the inward bending portion of the upper rim. An electron barrel for cathode ray tube is provided.

Hereinafter, the present invention will be described in more detail with reference to FIGS. 7 to 16 as follows.

7 is a perspective view showing a main portion of an electron gun to which an embodiment of the present invention is applied, and FIG. 8 is a perspective view of a first inclined extension electrode fixed in the first acceleration and focusing electrode of the present invention, and FIG. Fig. 2 is a perspective view of the second inclined extension electrode fixed in the second acceleration and focusing electrode.

According to the present invention, a single long hole through which three electron beams pass through the opposite surfaces of the first acceleration and focusing electrode 5 and the second acceleration and focusing electrode 6, which are installed to face each other and form the electrostatic focusing lens, is provided. (9) to form an upper rim (10) (11) to be bent from the outer circumferential surface of each electrode to the through side, and the inward bending portion 18 (bending into the inside of each electrode at the end of each upper rim) 19).

The first inclined extension electrode 23 having the head 20, the inclined portion 21, and the bottom portion 22 in the interior of the first acceleration and focusing electrode 5 (the proximity portion of the through hole) as shown in FIG. 8. The both sides of the vertically formed and the central hole (22a) formed in the first inclined extension electrode is formed only up to the bent surface of the inclined portion 21 and the bottom portion 22, one side of the first inclined extension electrode 23 It is fixed to be connected to the inward bending portion 18 of the upper rim (10).

The inclined portion 21 of the first inclined extension electrode 23 serves to increase the aperture of the main lens by smoothly forming an electric field.

In other words, it reduces spherical aberration and minimizes spot size.

The head 20 serves to weld and fix the first inclined extension electrode 23 to the inside of the first acceleration and focusing electrode 5.

Accordingly, three electron beam through holes are independently formed by the first inclined extension electrode 23 at the through hole 8 side of the first acceleration and focus electrode 5.

The second inclined extension electrode 24 is fixed to the inside of the second acceleration and focusing electrode 6 (the vicinity of the through hole).

In the embodiment of the present invention, as shown in FIG. 9, the structure of the second inclined extension electrode 24 forms a protrusion 25a side by side in both directions on the same plane of the head 25 and the head ( Between the 25 and the bottom portion 26 is formed an inclined portion 27 extending to the head, wherein the vertical inner diameter (A) of the protrusion 25a is smaller than the vertical inner diameter (B) of the upper rim (11) Form.

The reason why the vertical inner diameter A of the protrusion 25a is smaller than the vertical inner diameter B of the upper rim 11 is to correct the astigmatism in the dimensions of the electrode satisfying the static convergence.

However, as shown in FIG. 12 showing the structure of the second inclined extension electrode 24, the inclined portion 27 of the second inclined extension electrode extends the inner side wall of the horizontal rectangular continuous hole to protrude 25a. It may be formed to have a soft portion 28 perpendicular to the ().

The second inclined extension electrode 24 having such a structure improves the strength of the electrode as compared to the second inclined extension electrode 24 of the exemplary embodiment and of course plays the same role.

In addition, as shown by the dashed-dotted line in FIG. 9, the protrusion amount at which the head portion 25 of the second inclined extension electrode 24 protrudes into the central hole 26a is projected from the protrusion portion 25a at the side hole. It may be set larger so that the distance L 'of the central hole is smaller than the distance L of the side hole.

This is to better eliminate the astigmatism between the center hole and the side hole.

One side of the second inclined extension electrode 24 having the structure as described above is fixed in the second acceleration and focusing electrode 6 so as to be connected to the inward bent portion 19 of the upper rim 11.

Accordingly, three electron beam through holes are independently formed by the second inclined extension electrode 24 at the through hole 9 side of the second acceleration and focus electrode 6.

Referring to the operation and effects of the present invention configured as described above are as follows.

First, the first inclined extension electrode 23 is fixed to be connected to the upper rim 10 of the first acceleration and focusing electrode 5, and is connected to the upper rim 11 of the second acceleration and focusing electrode 6. When power is applied to the heater installed in the cathode 1 while the two inclined extension electrodes 24 are fixed, three electron beams are formed between the first, second acceleration and focusing electrodes 5 and 6 while proceeding to the screen group. Focused by electrostatic focusing lens.

As such, the spot size of the electron beam focused by the main capacitive lens is minimized by the first inclined extension electrode 23.

That is, as shown in FIG. 13, among the three electron beams emitted by the electron gun, the side beam 29 and the center beam 30 are the primary electrostatic focusing formed between the first, second acceleration, and the focusing electrodes 5, 6; By passing through the lens 31 to satisfy the static convergence matched at the center of the screen to eliminate the focusing difference in the horizontal direction and the vertical direction of the electrostatic focusing lens.

When there is no correction electrode during the operation as described above, in the state where the electrostatic focusing lens 31 satisfies the static convergence, the phenomenon of over-focusing occurs in the vertical direction.

However, when the protrusions 25a are formed side by side on both sides of the head 25 as in the present invention, the electron beam is prevented from being concentrated in the vertical direction to prevent the focusing difference from occurring in the horizontal and vertical directions. do.

Referring to FIG. 14, the principle of the second inclined extension electrode 24 is extended to the inward bending portion 19 extending from the inner end of the upper rim 11 of the second acceleration and focusing electrode 6. The head portion 25 and the protrusion portion 25a of the () are projected to the central axis (C-C ') in the vertical direction of the electrostatic focusing lens 31 than the inner surface end of the upper rim 11, so that the electron beam passing through The equipotential lines 32 are more convex by diverging further in the vertical direction of the main electrostatic focusing lens.

(A) and (b) of FIG. 15 are electron beams passing through the electrostatic focusing lens 31 provided with the protrusion 25a of the second inclined extension electrode 24 and the electrostatic focusing lens without the protrusion formed. The phenomenon at the time of operation is shown schematically.

As described above, in the capacitive focusing lens 31 ([(a) of FIG. 15) generated by forming the protrusion 25a of the second inclined extension electrode 24 in the second acceleration and focusing electrode 6, When the electron beam 33 passes through the electrostatic focusing lens by increasing the divergence power, the electron beam 33 is gradually focused to eliminate the focusing force difference with the horizontal direction. As shown in FIG. 16, the center and the periphery of the screen are small and dense. It is possible to obtain a high electron beam spot.

On the contrary, in the electrostatic focusing lens ((b) of FIG. 15) without the protruding portion, the focusing force in the vertical direction is enhanced so that the electron beam 33 is focused more and more on the central axis C-C '. Even the periphery of the halo (Halo) phenomenon can be seen that occurs.

In addition, when the inclined portion 27 of the second inclined extension electrode 24 extends to the inner diameter of the electrode, as shown in FIG. 12 of another embodiment, it is configured to have a connecting portion 28 perpendicular to the protrusion 25a. In the same operation as described above, a small and dense electron beam spot is obtained not only at the center portion but also at the periphery of the screen, and the connection portion 28 also serves to reinforce the strength of the second inclined extension electrode 24.

As described above, the present invention eliminates astigmatism, which is a difference between the horizontal focusing force and the vertical focusing force of the electron beam, without providing a correction electrode in the first and second acceleration and focusing electrodes, thereby improving deterioration of the focusing characteristic. In addition, since the distance between the electron beams is shortened, the deflection aberration caused by the deflection yoke is minimized.

Accordingly, it is possible to obtain an electron gun for a color cathode ray tube that effectively shortens the distance between each electron beam in the color cathode ray tube which requires a good concentration characteristic of each electron beam, but rather expands the aperture of the electrostatic focusing lens.

Claims (3)

Electron gun having an electron beam forming region consisting of a cathode, first and second grid electrodes, and a primary electrostatic focusing lens including first, second acceleration and focusing electrodes for substantially focusing three electron beams emitted from the electron beam forming region. In the first, second acceleration and focusing electrode to form a through-hole through which three electron beams pass, respectively, to form an upper rim bent from the outer peripheral surface of each electrode to the through-side, inclined in the first acceleration and focusing electrode Both sides of the bottom portion and the bottom portion are formed vertically, and the inside of the bottom portion is provided with a first inclined extension electrode formed with a central hole only to the bent surface of the inclined portion, so that one side of the first inclined extension electrode is inwardly bent in the upper rim; Fixed to be connected to the inside of the second acceleration and focusing electrode to form protrusions side by side in both directions on the same plane of the head of the second inclined extension electrode The color cathode-ray tubes the electron gun embodiments the vertical inner diameter smaller than the normal inner diameter of the upper rim is formed, wherein the second one side of the inclined extension electrode hayeoseo fixedly connected with the inwardly bent portion of the upper rim of the projecting portion. The electron gun body for color cathode ray tube according to claim 1, wherein an inclined portion of the second inclined extension electrode fixed to the second acceleration and focusing electrode is extended to an inner diameter side wall of the electrode to have a connection perpendicular to the protrusion. The electron gun sphere for color cathode ray tube according to claim 1 or 2, wherein the protrusion amount of the protrusion of the second inclined extension electrode provided in the second acceleration and focusing electrode is smaller than the protrusion amount of the head portion.