JPH0782815B2 - Electron gun for color picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an in-line type electron gun for a color picture tube, and in particular, so that the main lens electrodes facing each other can obtain a magnified aperture lens for reducing the beam spot diameter. An electron for a color picture tube, which is composed of an oval-shaped opening portion that forms one lens space deep in the tube axis direction, and a plate-shaped electrode arranged so as to divide the space into three parts therein. Regarding guns.

[Background of the Invention]

FIG. 1 shows a configuration example of a conventional in-line type electron gun for a color picture tube. The figure is a vertical cross-sectional view taken along a plane parallel to the arrangement direction of three electron beams and the tube axis direction. In the figure, 1 is a G1 electrode, 2 is a cathode support made of ceramics, and 3 is a cathode support. It is the cathode. 4 is a G2 electrode,
Reference numeral 5 is a G3 electrode, 6 is a G4 electrode, and the G3 electrode 5 and the G4 electrode 6 are also called main lens electrodes.

In this main lens electrode, as shown in an enlarged view in FIG. 2, three cylindrical electron beam passage openings 5a, 6a are formed in the facing surface with the hole edges narrowed inward. The electron gun shown in the figure is configured as a bipotential type electron gun, and has openings and shield cups of each electrode from the cathode 3 serving as each electron beam source to the beam passage opening 5a formed by the G3 electrode 5. The central axis of the aperture is the same as that of the aperture of 7, but the beam passage opening formed by the G4 electrode 6
Only 6a does not have the same central axis. Then, the three electron beams 8, 9, 10 emitted from the three cathodes 3 arranged in a line
Travels almost parallel to the electron gun axis X-X, but the two electron beams on the outer side do not coincide with each other on the outer side when the beam passage axes between the main lens electrodes are coincident with each other as shown in the figure. Interval S
On the other hand, since the gap S'on the G4 electrode side is displaced in the direction of increasing, it bends inward by the action of the tilted electrostatic lens formed during this, and the well-known static convergence is performed.

Generally, the resolution of a color picture tube depends on the size and shape of the beam spot appearing on the screen of the phosphor, and in order to obtain high resolution, it is important that the diameter of the beam spot is as small as possible and the shape distortion is small. is there. It is also important that the three electron beams properly converge at any one point on the phosphor screen surface.

On the other hand, in the in-line type color picture tube, as one of the power saving measures, there is a method of reducing the diameter of the neck so as to reduce the deflection power. When this method is adopted, the beam passage openings 5a and 6a in the main lens electrode are used. The lens aperture D formed in 1 is inevitably smaller than that of a lens having a large neck diameter. Further, when the beam passing aperture arrangement interval S is made small in order to obtain good convergence, the lens aperture D becomes small here as well. However, in the electron gun having the small lens aperture D formed by the main lens electrode as described above, a large lens is used. It is well known that the most predominant spherical aberration among the lens aberrations that causes the deterioration of the resolution of the picture tube is increased as compared with the one having the aperture, which is a major drawback of the conventional electron gun.

On the other hand, in the conventional electron gun, the beam passage gap of the G4 electrode 6 is displaced with respect to that of other electrodes below the G3 electrode 5 as a means for performing static convergence as described above.
In general, an appropriate value is conventionally used for the displacement amount for each screen size of the picture tube. Therefore, inevitably, different electrode parts and electron gun assembling devices are required for each displacement amount, in other words, for each screen size, resulting in an increase in the required number of electron gun assembling devices or a complicated assembling device. There was a need for switching, and there was a problem in terms of automating the assembly.

[Object of the Invention]

The present invention has been made in view of such circumstances, and an object thereof is to increase the diameter of the main lens in the same neck diameter,
An object of the present invention is to provide an electron gun for a color picture tube capable of facilitating automation of assembly.

[Outline of Invention]

In order to achieve such an object, the present invention separates a pair of main lens electrode structures facing each other into an electrode cup part and a correction electrode plate and retracts the correction electrode plates in a direction away from each other. A single elliptical aperture provided in the electrode cup component forms a vast lens space, and the aperture provided in the correction electrode plate and notches provided on both sides of the aperture are provided. The beam passage formed with the inner surface of the electrode cup component is made elliptical to absorb astigmatism, and a plurality of small apertures or a plurality of small apertures are formed as an assembly guide around the apertures and notches forming these beam passages. The notch is arranged. Hereinafter, the present invention will be described in detail with reference to examples.

Example of Invention

FIG. 3 shows a main lens structure of an embodiment in which the present invention is applied to a bipotential type electron gun. The figure (a) is a sectional view taken along a plane including the tube axis direction and the arrangement direction (horizontal direction) of three electron beams, and the figure (b) is the tube axis direction and the tube axis direction and the arrangement of the electron beams. A cross-sectional view taken along a plane including the direction perpendicular to the direction (vertical direction), the same figure (c) is the G4 electrode
The front view of the G3 electrode 30 seen from the 40 side, FIG.
A cross-sectional view corresponding to the portion -d and FIG. 7E are partially cutaway perspective views showing an example of mounting the correction electrode plate on the G3 electrode 30.

In FIG. 3A, the G3 electrode 30 and the G4 electrode 40 face each other with a gap g, and the G3 electrode 30 includes a cup electrode 31 and a lower electrode 32.
The G4 electrode 40 includes a shield cup 50 on the upper portion of the cup electrode 41.

G3 and G4 electrodes 30 and 40 have a single horizontal length h and a vertical length v whose edges are bent inward at a bending height H and have the same length. Circular aperture 311,41
1 has a semicircular shape having a radius of 1/2 of the vertical dimension v at both ends in the horizontal direction of the oval holes 311 and 411. It matches S. Then, in the G3 and G4 cup electrodes 31 and 41, correction electrode plates 33 and 43 are arranged perpendicularly to the tube axis direction at positions retracted from the opposite end faces by a predetermined distance d ₁ and d ₂ , respectively.
Are assembled by welding. The correction electrode plates 44 and 43 are provided with elliptical holes 331 which are long in the vertical direction and serve as the central electron beam passage among the three electron beam passages, as shown in FIG.
And a semi-elliptical opening 332 in the form of a notch that is long in the vertical direction and surrounds the beam passages on both sides substantially half, and the center of the semi-elliptical opening 332 coincides with the S dimension. Further, the correction electrode plate 33 is provided with four small circular apertures 333. In FIG. 6E, the G3 electrode has been described as an example, but the correction electrode plate 43 on the G4 electrode side has the completely same structure. However, the dimensions of the elliptical aperture and the semi-elliptical opening that both have are set to the optimum dimensions for the reasons described below, so G
There is no coincidence between the 3, G4 electrodes or between the central elliptical aperture and the semi-elliptical mouth. Further, since the cup electrode and the correction electrode plate are separately assembled, the elliptical major axis dimension of the correction electrode plate can be formed to be equal to or larger than the vertical dimension v of the oval hole formed by the cup electrode. This has the effect of increasing the design margin when setting optimum dimensions.

In the above configuration, the correction electrode plates 33 and 43 are set back to each other, thereby achieving the purpose of reducing spherical aberration by enlarging the diameter of the main lens. That is, in FIG. 3B, elliptical holes 311 and 4 extending from the electrode facing end surface to the correction electrode plates 33 and 43.
In the space regions 312 and 412 including 11, the counter electrode potential penetrates deeply to form a vast lens space. That is, G3
The G4 electrode potential is in the electrode lens space area 312, and the G3 electrode potential is in the G4 electrode lens space area 412.
Since it penetrates substantially in the same size as the hole size, it is possible to obtain a lens diameter significantly larger than that of the cylindrical lens formed by the main lens electrode of the conventional electron gun.

However, the lens space area 3 following these openings 311 and 411
The lens electric field generated at 12,412 is naturally asymmetrical because the horizontal and vertical dimensions of the elliptical aperture are asymmetric in the inner half regions of the central beam and both beams, and the lens action is Astigmatism occurs in both horizontal and vertical directions. On the other hand, in the outer half regions of the beams on both sides, the elliptical apertures 311 and 411 are semicircles, and the center dimension thereof is the same as the S dimension, so that an axisymmetric lens is configured and astigmatism does not occur. . Therefore, a means for astigmatism correction is required in the central half area that produces astigmatism and the inner half areas of both side beams, but in the present invention, the correction electrode plate 3 is used.
This role is assigned to 3,43.

That is, in general, the lens action becomes stronger as the size of the aperture becomes smaller. Therefore, in FIG. 7C, the lens action in the apertures 311 and 411 in which the vertical dimension v is smaller than the horizontal dimension h and the space regions 312 and 412 subsequent thereto are horizontal. It becomes stronger in the vertical direction than in the direction. In order to correct this, in the present invention, in the correction electrode plates 33, 43, the central electron beam passage ports 331, 431 have an elliptical shape that is long in the vertical direction, and the beam passage ports on both sides have a notch shape in which approximately half of the inside is long in the vertical direction. Semi-elliptical mouth 332,43
Form in 2. As a result, the lens action in the correction electrode plate becomes stronger in the horizontal direction than in the vertical direction, and by appropriately setting the ratio of the major axis and the minor axis of the elliptical dimension, the balance with the vast lens space area described above can be achieved. Astigmatism is removed. The inward bending of the elliptical holes 311 and 411 of the G3 and G4 cup electrodes 31 and 41, respectively, is provided to increase the high-voltage characteristics of the electron gun electrode. It is also effective in increasing the strength of 31,41 parts.

FIG. 4 is for explaining the static convergence method in the electron gun of this embodiment, and is an enlarged sectional view of the facing portion of the G3 and G4 electrodes. In the figure, the retreat amount of the correction electrode plate 33 on the G3 electrode side is d ₁ = 3 mm, and the correction electrode plate 43 on the G4 electrode side is
The retreat amount of is set to d ₂ = 2 mm. In this case, as described above, the counter electrode potential deeply penetrates into each oval-shaped opening and the space area following it to form a vast lens space. Then, due to the effect of the wall at the edge of the oval-shaped aperture, the penetration of the counter potential becomes shallower than in the vicinity of the central beam passage opening. As a result, the electron beams on both sides encounter the equipotential lines 60 that are inclined in the vast lens space area of the G3 electrode, so they are subjected to the concentration effect by the inclined electrostatic lens action here, and the outer electron beams 8 and 10 are Bend inward. However, at this time, if the retreat amount d ₂ on the G4 electrode side matches with d ₁ , the electron beam will be bent even if the G3 electrode is bent inward.
Since 8 and 10 encounter the similarly inclined equipotential lines 70 in the vast lens space of the G4 electrode, the diverging lens action at the G4 electrode cancels the above-described inward concentration action. Therefore, in this embodiment, d ₂ is set to be ₁ mm shallower than d ₁ , and G4
The equipotential line 70 in the electrode-side space area has a gentler slope than the G3 side equipotential line 60. As a result, the beam focusing effect on the G3 electrode side becomes dominant over the beam diverging effect on the G4 electrode side, and static convergence is performed. Even if the screen size of the picture tube changes, the retreat amount d ₁ , d
_It can be handled by selecting ₂ appropriately.

5 to 7 show a method of assembling the cup electrode and the correction electrode plate. Here, the G3 electrode is taken as an example, but the same applies to the G4 electrode. 5 (a) is a front view showing the correction electrode plate 33, FIG. 5 (b) is a sectional view taken along line bb, FIG. 6 (a) is a front view showing the cup electrode 31, and FIG. 6 (b) is b. -B sectional view, 7th
Figure (a) is a front view showing an assembly jig, and Figure (b) is bb.
A sectional view is shown. The vertical outer diameter w of the correction electrode plate 33 is substantially the same as the cup electrode inner diameter W.

In FIG. 7 (b), a core metal 81 is attached to the fixing plate 80 of the jig,
A cored bar 82 is provided at a position corresponding to the circular hole 333 provided in the correction electrode plate. Core bar installed at the same interval as the S dimension during assembly
Reference numeral 81 determines the position in close contact with the semicircular portion of the elliptical opening of the cup electrode. Then, the cup electrode 31 is placed on the spacer 83 as shown by the one-dot chain line in the figure. Next, the correction electrode plate 33 is inserted into the core metal 82, using the circular opening 333 as a guide,
It is placed on the upper surface of the core metal 81 as shown by the chain double-dashed line in the figure. In this state, the assembly is completed by welding in the vertical direction where the two are in close contact with each other.

In this way, the correction electrode plate has an opening 333 as a guide for assembly.
Even if the elliptical dimension changes in response to changes in the screen size of the picture tube, the same jig can be used regardless of the change in the screen size of the picture tube, as long as the positional relationship of the apertures is kept constant. Assembly can be performed. Further, as described above, in this embodiment, by appropriately selecting the retreat amounts d ₁ and d ₂ of the auxiliary electrode plates, static convergence can be achieved without the need to shift the aperture axes of the G3 and G4 electrodes as in the conventional case. Since it can be obtained, the oval holes formed by the G3 and G4 electrodes can be set to have exactly the same size, and in that respect, it is also suitable for assembly automation. In that case, the mounting position of the correction electrode plate, that is, the amount of retreat can be easily set to an arbitrary dimension simply by changing the thickness t of the spacer 83.

It should be noted that the aperture 333 may be any guide that serves as a positioning guide during assembly as described above, and is not necessarily an "aperture" and may be, for example, a notch portion such as 333 'shown in FIG. It goes without saying that it is okay.

FIG. 9 shows an example of an electron gun assembly other legislation. 3A is a sectional view taken along the same section as FIG. 3A, and FIG. 3B is a sectional view corresponding to a portion bb. Two cored bars 91 are installed on the fixed plate 90, and the distance between them corresponds to the S dimension. The cored bar 91 has a stepped portion 911 and a semicircular portion 912 having a cross section formed by cutting a cylinder coaxial therewith into a substantially semicircular shape. Using the core metal 91 as a guide, the G4 electrode 40 is first inserted, and the spacer 92 determines the electrode gap g, and then the G3 electrode 30 is inserted. At this time, the G3 and G4 electrodes each have the same dimensions, and the semicircular portions at the horizontal ends of the elliptical openings 311 and 411 that are not affected by the dimensional change for each picture size of the picture tube are the assembly standards. As described above, the center position coincides with the S dimension, so only that part is the semicircular part 912 of the core metal 91.
Therefore, the assembling accuracy between the electrodes can be secured regardless of the retreat amount of the correction electrode plate and the elliptical dimension. Insert the G2, G1 electrodes, etc., not shown in the figure, and fix them with a support such as glass.
Complete the assembly.

〔The invention's effect〕

As described above, according to the present invention, the correction electrode plate provided with the elliptical opening and the semi-elliptical notch in the cup electrode provided with the single elliptical opening, and Since the correction electrode plate is provided with a plurality of small holes or notches to serve as an assembling guide, there is an advantage that the diameter of the main lens can be enlarged and the assembling can be easily automated.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a conventional electron gun for a color picture tube, FIG. 2 is a sectional view showing a configuration example of a main lens electrode, and FIG.
(A) and (b) are sectional views of a main lens electrode showing an embodiment of the present invention, (c) is a front view of essential parts, (d) is the same sectional view, and (e) is the same. Is a partially broken perspective view, FIG. 4 is a view for explaining static convergence, FIG. 5 (a) is a front view showing a correction electrode plate, FIG. 5 (b) is a sectional view, and FIG. 6 (a). Is a front view showing a cup electrode, FIG. 7 (b) is a sectional view, FIG. 7 (a) is a plan view showing a main lens electrode assembly jig, FIG. 7 (b) is a front view, and FIG. 8 is a correction electrode. FIGS. 9A and 9B are front views showing another configuration example of the plate, and FIGS. 9A and 9B are sectional views showing a configuration example of the electron gun assembly apparatus. 1 …… G1 electrode, 2 …… cathode support, 3 …… cathode, 4 …… G2 electrode, 5,30 …… G3 electrode, 6,40 …… G4 electrode,
7 ... Shield cup, 8,9,10 ... Electron beam, 31,41
...... Cup electrode, 32 ...... Lower electrode, 33,43 …… Correction electrode plate, 311,411 …… Oval opening, 312,412 …… Lens space area, 331,431 …… Elliptical opening, 332,432 …… Semi-elliptical opening, 333
...... Circular opening (small opening), 333 '…… Notched part.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiaki Iitaka 2 3350 Hayano, Mobara-shi, Chiba 2 Hitachi Device Engineering Co., Ltd. (56) References JP-A-57-74950 (JP, A) JP-A-59 -54151 (JP, A)

Claims (2)

[Claims] 1. A color picture tube comprising an electron beam source for radiating three electron beams in a row, and a main electron lens section for focusing the electron beam from the electron beam source on a phosphor screen. In the electron gun, the main electron lens portion has two electrodes arranged so as to face each other at a constant interval in the tube axis direction, and both the counter electrodes are provided with edge portions on respective facing surfaces. Is provided with a single horizontally elongated oval opening bent inward to form a lens space deep in the tube axis direction, and the opening edge portion is provided in the lens space. The correction electrode plates are arranged apart from the tip of the bent portion and perpendicular to the tube axis direction, and each correction electrode plate serves as a passage for the central electron beam among the three electron beams. Oval aperture with major axis in the direction perpendicular to the direction , A semi-elliptical notch having a major axis in the vertical direction, which surrounds approximately half the circumference of the electron beam passages on both sides, and a plurality of small holes arranged around these elliptical openings and semi-elliptical notches. An electron gun for a color picture tube, comprising: an assembling guide having an opening or a notch. 2. The collar according to claim 1, wherein the distance from the tip of the bent portion of the edge of the elliptical hole of each of the correction electrode plates is different between the opposing electrodes. An electron gun for a picture tube.