JP3818074B2 - Color picture tube - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color picture tube device, and more particularly to an electrode constituting a main lens for focusing three electron beams on a fluorescent screen.
[0002]
[Prior art]
In general, a color picture tube apparatus has an envelope composed of a panel and a funnel integrally joined to the panel, and three electron beams emitted from an electron gun disposed in the neck of the funnel are A color image is projected by projecting on a phosphor screen formed by facing the shadow mask on the inner surface of the panel while being scanned horizontally and vertically while being deflected by horizontal and vertical deflection magnetic fields generated by a deflection device mounted on the outside. It is formed to display.
[0003]
In general, the magnetic field of the deflecting device used in such a color picture tube device has a self-convergence configuration in which three electron beams are concentrated on the screen. The deflection magnetic field is distorted in a barrel shape. For this reason, the three electron beams that pass through the deflection magnetic field receive a diverging action in the horizontal direction and a focusing action in the vertical direction. Such a focusing effect stronger in the vertical direction than in the horizontal direction is called negative astigmatism.
[0004]
When the electron beam trajectory becomes longer as the deflection angle increases, the negative astigmatism appears remarkably in the periphery of the phosphor screen surface due to the self-convergence magnetic field as described above, and the electron beam spot becomes horizontal. There is a problem that the horizontal resolution is reduced due to a horizontally long and flat cross-sectional shape with the long axis in the direction. This problem has become more prominent due to the flattening of panels and the expansion of the deflection angle as in recent years.
[0005]
Therefore, in order to draw an image with high resolution on the phosphor screen surface, it is necessary to reduce the spot diameter in the horizontal direction with an electron gun.
[0006]
In general, the spot diameter in a color picture tube device can be made smaller as the spherical aberration at the main lens of the electron gun is smaller. When the incident angle of the electron beam to the main lens is α, the spot diameter δ to which the most dominant spherical aberration among the main lenses contributes is
δ = (M · Csp · α ³ ) / 2
It is expressed. Here, M is a lens magnification, and Csp is a spherical aberration coefficient. When the lens action of the main lens is weakened, the lens magnification and spherical aberration are reduced, that is, the spot diameter on the phosphor screen can be reduced by effectively increasing the main lens aperture.
[0007]
As shown in FIG. 11, a main lens of a conventional electron gun for a color picture tube disclosed in Japanese Patent Publication No. 2-18540 includes a focusing electrode 32 and a final accelerating electrode which are spaced apart from each other in the tube axis direction. 33 and a shielding cup 34 connected to the final acceleration electrode. The focusing electrode 32 and the final accelerating electrode 33 are arranged so that the electron beam is almost retreated from the outer peripheral electrodes 35 and 36 that surround the three electron beams 8a, 8b, and 8c and the opposing end faces of the outer peripheral electrodes 35 and 36, respectively. It consists of electrode plates 37 and 38 (hereinafter referred to as “vertical electrode plates”) arranged so as to pass vertically.
[0008]
A plan view of the vertical electrode plates 37 and 38 is shown in FIG. The openings 39a, 39b, 39c, 40a, 40b, and 40c of the vertical electrode plates 37 and 38 are formed so that the horizontal diameter is smaller than the vertical diameter. In this way, the vertical electrode plates 37 and 38 disposed inside the outer peripheral electrodes 35 and 36 of the focusing electrode 32 and the final acceleration electrode 33 forming the main lens are retracted, so that the final acceleration electrode is placed inside the focusing electrode. A high potential is penetrated deeply, and a low potential of the focusing electrode is penetrated deeply into the final acceleration electrode to effectively increase the main lens aperture, thereby reducing the spot diameter on the phosphor screen.
[0009]
Further, because of the outer peripheral electrode having a major axis in the horizontal direction, negative astigmatism in which the lens focusing action in the vertical direction is stronger than in the horizontal direction is caused, and the horizontal aperture diameter Rh of the vertical electrode plates 37 and 38 is set in the vertical direction. The diameter is smaller than the opening diameter Rv, and is removed by suppressing the penetration of the potential in the horizontal direction.
[0010]
[Problems to be solved by the invention]
However, in such an electron gun of a conventional color picture tube device, there is a limit in simultaneously performing enlargement of the main lens aperture and adjustment of astigmatism. In this technology, the vertical electrode plate is retracted to enlarge the main lens aperture, but on the other hand, the horizontal diameter of the aperture of the vertical electrode plate is reduced to adjust astigmatism. In particular, there is a limit to increasing the main lens diameter in the horizontal direction.
[0011]
The present invention can easily adjust astigmatism with a relatively simple configuration, and can increase the main lens aperture. In particular, the horizontal lens aperture is increased to increase the horizontal resolution. An object of the present invention is to provide a color picture tube having a main lens part structure capable of supporting.
[0012]
[Means for Solving the Problems]
The color picture tube of the present invention is a color picture tube comprising an envelope comprising a front panel on which a phosphor screen is formed and a funnel, and an inline electron gun provided in a neck portion of the funnel. A converging electrode and a final accelerating electrode which are provided opposite to each other in the tube axis direction of the neck portion at a predetermined interval to form a main lens, and on the phosphor screen surface side of the final accelerating electrode At least one electron beam passage hole at the bottom, and a shielding cup connected to the final acceleration electrode through the bottom, the focusing electrode and the focusing electrode among the final acceleration electrodes internal only, the electron beams are three three electron beam through holes each of which passes a is vertical electrode plate which is formed is provided in a line shape, and, Serial inside the final accelerating electrode out of the focusing electrode and the final accelerating electrode only, said substantially parallel to the line plane extending toward the focusing electrode is screen-shaped horizontal electrode plate of the electron beam apertures of the shielding cup It is provided in at least one of the upper and lower sides, and an opening surrounding three electron beams is provided on the end surface on the final acceleration electrode side of the focusing electrode and the end surface on the focusing electrode side of the final acceleration electrode .
[0013]
With this configuration, astigmatism can be corrected without impairing the effect of expanding the main lens aperture in the horizontal direction. Therefore, even when the horizontal distortion of the spot around the phosphor screen surface becomes noticeable due to the flattening of the phosphor screen panel and the increase in the deflection angle, the horizontal distortion is reduced by reducing the peripheral spot diameter in the horizontal direction. It is possible to provide a color picture tube device with reduced and high resolution.
[0014]
Moreover, it is preferable that the electron beam passage hole formed in the bottom part of the said shielding cup is circular.
[0015]
With this configuration, the shape of the assembly jig used when assembling the electron gun can be made circular, and it is not necessary to have a complicated shape. Therefore, the assembly jig can be easily processed and the electron gun can be easily assembled. .
[0016]
Moreover, it is preferable that at least one of the electron beam passage holes formed in the bottom of the shielding cup is non-circular.
[0017]
With this configuration, the amount of astigmatism given to the three electron beams can be individually adjusted. Also, the variation in the amount of astigmatism can be limited only by the punching accuracy of the electron beam passage hole.
[0018]
Moreover, it is preferable that the diameter of the central opening among the three openings of the vertical electrode plate is small in the in-line direction and large in the direction perpendicular to the direction.
[0019]
With this configuration, it is possible to remove negative astigmatism in the electron beam passing through the central aperture, which is stronger in the lens focusing action in the vertical direction than in the horizontal direction due to the outer peripheral electrode having a major axis in the horizontal direction.
[0020]
The horizontal electrode plate preferably has different heights near the central beam of the three electron beams and near the beams on both sides.
[0021]
With this configuration, the amount of astigmatism given to the three electron beams can be individually adjusted.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0023]
The color picture tube shown in FIG. 2 has an envelope composed of a panel 1 and a funnel-shaped funnel 2 integrally joined to the panel 1. On the inner surface of the panel 1 is formed a phosphor screen 3 composed of phosphor layers of three colors that emit blue, green, and red, and a large number of electron beam passage holes are formed facing the phosphor screen 3. A shadow mask 4 is arranged. An electron gun 6 is disposed on the neck portion 5 of the funnel 2. The deflection yoke 7 is attached to the boundary between the large diameter portion of the funnel 2 and the neck portion 5 and deflects the electron beam 8 emitted from the electron gun 6 in the horizontal and vertical directions.
[0024]
As shown in FIG. 1, the main lens of the electron gun of the present invention is composed of a focusing electrode 23, a final acceleration electrode 24, and a shielding cup 25 connected to the final acceleration electrode 24. Yes. As shown in FIGS. 1 and 3, the focusing electrode 23 that forms the main lens includes an outer peripheral electrode 26 that surrounds three electron beams (not shown), and a vertical electrode plate 28. The vertical electrode plate 28 is formed with three apertures 30a, 30b and 30c through which an electron beam passes.
[0025]
The final acceleration electrode 24 is composed of only the outer peripheral electrode 27 that surrounds the three electron beams 8a, 8b, and 8c. As shown in FIGS. 1 and 4, three apertures 31 a, 31 b, 31 c having an inner diameter R through which the electron beams 8 a, 8 b, 8 c pass are formed in the shielding cup 25 disposed on the screen side end surface of the outer peripheral electrode 27. A pair of electrode plates (hereinafter referred to as “horizontal electrode plates”) 29 extending toward the focusing electrode 23 are disposed above and below the openings 31a, 31b, 31c of the shielding cup 25.
[0026]
In general, in a color picture tube electron gun, a low potential is applied to the focusing electrode 23 and a high potential is applied to the final acceleration electrode 24, a focusing lens is formed on the focusing electrode side, and a diverging lens is formed on the final electrode side. Becomes the main lens electric field. The horizontal electrode plates 29 disposed above and below the openings 31a, 31b, and 31c of the shielding cup 25 are electrically connected to the final acceleration electrode 24 and applied with a high potential, so that they penetrate into the final acceleration electrode 24. The low potential is suppressed only in the vertical direction, and only the diverging lens in the vertical direction is strengthened. Therefore, it is possible to remove the focusing effect of the lens in the vertical direction stronger than the horizontal direction, that is, negative astigmatism, generated by the outer peripheral electrodes 26 and 27 having the long axis in the horizontal direction.
[0027]
Also, unlike the conventional main lens, there is no vertical electrode plate that prevents the penetration of low potential inside the final acceleration electrode, so that the low potential of the focusing electrode can penetrate deeper into the final acceleration electrode especially in the horizontal direction. The main lens aperture in the horizontal direction can be enlarged.
[0028]
Up to this point, it has been explained that the negative astigmatism that has a stronger lens focusing effect in the vertical direction than in the horizontal direction has been described. However, in the present invention, the effective astigmatism is further adjusted by adjusting the astigmatism. In addition, the main lens aperture in the horizontal direction can be further enlarged.
[0029]
FIG. 5 shows the horizontal main lens aperture with respect to the height (length in the tube axis direction) h of the horizontal electrode plate obtained by three-dimensional simulation, and astigmatism with a stronger lens focusing effect in the horizontal direction than in the vertical direction. The amount relationship (this is called positive astigmatism) is shown. It can be seen that as the height h is increased, the action of the focusing lens stronger in the horizontal direction than in the vertical direction is increased, and at the same time, the main lens aperture in the horizontal direction can be further enlarged.
[0030]
As described above, the self-convergence magnetic field tends to cause negative astigmatism because the electron beam spot on the phosphor screen surface tends to be distorted into a horizontally long flat shape with the long axis in the horizontal direction, particularly in the periphery of the phosphor screen surface. In addition to removing aberrations, it is effective to reduce the horizontal spot diameter in the peripheral part by giving positive astigmatism to the main lens.
[0031]
That is, in the present invention, by adjusting the height h of the horizontal electrode plate 29, the positive astigmatism given to the main lens is increased and the main lens aperture in the horizontal direction is further enlarged, whereby the phosphor screen surface Resolution can be further increased.
[0032]
Also, according to the present invention, unlike the conventional electron gun, there is no vertical electrode plate inside the final accelerating electrode, so the horizontal electrode plate height h is not limited by the position of the vertical electrode plate. Therefore, it is very suitable for giving the main lens a stronger focusing lens action in the horizontal direction than in the vertical direction. The horizontal electrode plate height h can be freely changed to reduce the horizontal spot diameter and reduce the resolution. Improvement can be easily achieved.
[0033]
Specific examples are shown below. As shown in FIG. 3, the horizontal aperture diameter Dh = 19.2 [mm] of the focusing electrode 23, the vertical aperture diameter Dv = 8.2 [mm], and the three apertures 30a, 30b, 30c of the vertical electrode plate 28. Vertical diameter Vc = Vs = 8.0 [mm], horizontal diameter hc of center opening 30b = 4.7 [mm], horizontal diameter hsi of side openings 30a and 30c = 2.35 [mm], hso = 4 0.0 [mm], and the retraction amount L of the vertical electrode plate 28 = 5.0 [mm]. As shown in FIG. 4, the diameter R of the three openings 31a, 31b, 31c of the shielding cup 25 is R = 4.8 [mm], and the width w of the electrode plate 29 disposed in the shielding cup 25 is 6.5. [Mm], the eccentric distance S of all the openings S = 5.5 [mm].
[0034]
At this time, if the height h of the electrode plate 29 is 0 [mm] and the amount of astigmatism is 0 [V], the effective horizontal diameter of the main lens is set to a large aperture of φ9.6 [mm]. Can do. Furthermore, if the height h of the electrode plate 29 is 5.0 [mm] and the astigmatism amount is 1700 [V], the effective horizontal diameter of the main lens is further increased to φ10.6 [mm]. Can do.
[0035]
In the above embodiment, the three opening shapes of the shielding cup 25 are all circular. However, as shown in FIGS. 6, 7, 8, and 9, the center hole 31b or the side hole 31a of the shielding cup is used. The astigmatism amount given to the three electron beams can be individually adjusted by making the aperture shape of 31c noncircular. Further, since the astigmatism amount is adjusted by the hole shape, the variation in astigmatism can be limited only by the punching accuracy of the aperture, and there is an advantage that the variation can be reduced.
[0036]
Also, the three openings formed in the bottom of the shielding cup 25 are not formed corresponding to the three electron beams as in the above embodiment, but may be formed as one common opening. it can.
[0037]
As shown in FIG. 10, the amount of astigmatism given to the three electron beams can be individually adjusted by changing the height of the horizontal electrode plate 29 between the central portion and both end portions.
[0038]
Further, although the final acceleration electrode 24 and the shielding cup 25 have been described as separate members, they may be formed as an integrated object.
[0039]
The invention described above can be applied to a color picture tube apparatus using an electron gun forming a main lens.
[0040]
【The invention's effect】
As described above, according to the present invention, with a relatively simple structure, negative astigmatism is removed, and at the same time, the main lens aperture is increased, and in particular, the horizontal lens aperture is increased to increase the size of the phosphor screen. The spot diameter can be reduced. In addition, since it is easy to give positive astigmatism to the main lens, the spot diameter can be further reduced by further increasing the lens diameter in the horizontal direction, and the focus characteristics of the color picture tube can be greatly improved. effective.
[0041]
Furthermore, in the present invention, since there is no electrode plate inside the final acceleration electrode, it is possible to regulate the position only with the outer peripheral electrode using a jig having the same diameter and the same diameter as the final acceleration electrode and the focusing electrode when the electron gun is assembled. Thus, since it is not necessary to regulate the electrode plate with a jig, it is possible to eliminate the deformation of the electrode plate that significantly deteriorates the focus characteristics and to improve the assembly accuracy of the electron gun.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of the vicinity of a main lens of the present invention. FIG. 2 is a cross-sectional view of a color picture tube. FIG. 3 is a plan view of a focusing electrode of the present invention. 5 is a graph showing the relationship between the height h of the horizontal electrode plate, the main lens diameter in the horizontal direction, and the amount of positive astigmatism. FIG. 6 is a diagram showing the shape of the electron beam passage hole on the bottom surface of the shielding cup of the present invention. FIG. 7 is a diagram showing the shape of an electron beam passage hole on the bottom surface of the shielding cup of the present invention. FIG. 8 is a diagram showing the shape of an electron beam passage hole on the bottom surface of the shielding cup of the present invention. FIG. 10 is a view showing another embodiment of the horizontal electrode plate of the present invention. FIG. 11 is a cross-sectional view of a main lens portion of a conventional electron gun. Electrode plan [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Panel 2 Funnel 3 Phosphor screen 4 Shadow mask 5 Neck part 6 Electron gun 8, 8a, 8b, 8c Electron beam 17 Main lens 23 Focusing electrode 24 Final acceleration electrode 25 Shielding cup 26, 27 Outer peripheral electrode 28 Vertical electrode plate 29 Horizontal electrode plates 30a, 30b, 30c, 31a, 31b, 31c Electron beam passage holes

Claims (5)

In a color picture tube comprising an envelope comprising a front panel and a funnel on which a phosphor screen is formed, and an in-line electron gun provided in the neck portion of the funnel,
The in-line electron gun is
A focusing electrode and a final accelerating electrode provided opposite to each other in the tube axis direction of the neck portion to form a main lens;
On the phosphor screen surface side of the final acceleration electrode, at least one electron beam passage hole is provided at the bottom, and has a shielding cup connected to the final acceleration electrode through the bottom,
A vertical electrode plate in which three electron beam passage holes through which each of the three electron beams pass is formed in-line only within the focusing electrode of the focusing electrode and the final acceleration electrode. And
The focusing electrode and only inside the final accelerating electrode of the final accelerating electrode, said substantially parallel to the line plane extending toward the focusing electrode is screen-shaped horizontal electrode plate of the electron beam apertures of the shielding cup Provided in at least one of the top and bottom ,
A color picture tube, wherein openings for enclosing three electron beams are provided on an end surface on the final acceleration electrode side of the focusing electrode and an end surface on the focusing electrode side of the final acceleration electrode .   2. A color picture tube according to claim 1, wherein there are three electron beam passage holes formed in the bottom of the shielding cup and are circular.   2. The color picture tube according to claim 1, wherein at least one of the electron beam passage holes formed in the bottom of the shielding cup is non-circular.   4. The collar according to claim 1, wherein a diameter of a central opening among the three openings of the vertical electrode plate is small in an in-line direction and large in a direction perpendicular to the direction. Picture tube.   5. The color picture tube according to claim 1, wherein the horizontal electrode plate has different heights near a central beam of the three electron beams and near both side beams.

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