JPH0212740A - Electron gun for color cathode-ray tube - Google Patents

Abstract

PURPOSE:To reduce the influence to the static focus property of electron beams even though the focus voltage is varied, by forming inclines at both outer opening holes of a focus electrode. CONSTITUTION:By making inclination of rectangular slopes 24S formed at both outer side openings 24R1 and 24B1 of the closed surface of a focus electrode 24 opposing to a G2 electrode 13, or its center eccentric to the centers 24R and 24B of openings engraved at both sides, it is made possible to reduce the concentration sensitivity of three electron beams to the variation of the focus voltage, or to maintain the concentration rate constant. Moreover, since the rectangular slope 24S is made eccentric to the center of the opening hole, the centers of the G2 electrode 13 and the G3 electrode 24 are not necessary to make eccentric, and the assembly accuracy in the electron gun assembling when a jig core rod is penetrated to the opening hole is never reduced. And since slopes are formed to both outer side opening holes 24R1 and 24B1, the eccentricity between the opening holes to focus the electron beams in the main electron lens can be reduced compared to the conventional unit. Consequently, the aberration owing to the astigmatism of the main electron lens is reduced, the focus performance of the electron lens is improved, and the resolution of the electron lens can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a color cathode ray tube electron gun, and particularly to a color cathode ray tube electron gun of a static focusing type in which the static concentration amount of the electron beam does not change due to fluctuations in the focusing voltage applied to the electron gun. Regarding cathode ray tube electron guns.

[Conventional technology]

In the electron gun used in color cathode ray tubes, three electron beams emitted from the cathode are focused by a main electron lens so that the minimum beam is obtained on the fluorescent screen of the cathode ray tube. It is constructed so that the beam is focused on a single point at the center of the phosphor screen.

The operation of concentrating multiple electron beams on a single point at the center of the phosphor screen is generally called static concentration.As a means of this, multiple electron beams are configured as independent electron guns with individual cathodes, and multiple or There is a method of mechanically tilting the electron guns on both sides of an in-line electron gun so that they concentrate on one point. As another method, multiple electron guns may be configured to emit parallel electron beams, and the central axis of the final stage electrode of the main electron lens may be eccentric to the outside to electrically concentrate the electron beams, or the electrodes may be placed opposite each other. It is common practice to mechanically concentrate the surfaces by tilting them.

FIG. 5 shows the configuration of the latter conventional in-line type electron gun 1 mentioned above, in which the electrode structure consists of three electrode structures that are insulated from each other and arranged in a line in the same plane with equal distances So maintained. one cathode assembly 11, and G1 electrodes 12 facing the cathode assembly 11 and sequentially arranged in the electron beam traveling direction. G2 electrode 13.
G3 electrode 14, G4 electrode 15. and a shielding magnetic pole 16, and each electrode except the shielding magnetic pole 16 is fused and fixed to an insulator support rod via each electrode support part (not shown) to maintain a predetermined electrode spacing.

G1 electrode 12. G2 electrode 13. , each opening 12R, 12G, 12B through which the electron beam of the G3 electrode 14 passes; 1
3R, 13G, 13B; 14R1, 14Gi,
14B1, 14R2, 14G2.1482 are also arranged in a line in the same plane with equal distances SO, and the three cathodes 11R, IIG, IIB of the cathode structure 11
The electron beam emitted from the parallel path 10R, LOG,
It is accelerated to advance on the IOB. The distance S' between the apertures 15R, 115G, and 15B of the G4 electrode 15 is somewhat larger than the above-mentioned So, and the distance S' between the apertures 15R, 115G, and 15B of the G4 electrode 15 is slightly larger than the distance S' of the main electron lens formed in each corresponding aperture gap between the G3 electrode 14 and the G4 electrode 15. An asymmetrical electric field is formed in the outer part of the cathode ray tube, and the two outer electron beams are electrostatically focused at the center of the fluorescent screen of the cathode ray tube into a central electron beam at the same time. The G3 electrode 14 is composed of two closed cylindrical bodies 141° 14□ with the flanged edges of the open end superimposed on each other, and the G4 electrode 15 is also a closed cylindrical body, but the flanged edge of the open end side has a A shielding magnetic pole 16 is attached.

[Problem to be solved by the invention]

In such a conventional electron gun 1, the concentration of the electron beam is
Opening interval difference Δs between the third electrode 14 and the G4 electrode 15 = s'-8
, and the ratio of the focusing voltage ■2 applied to the G3 electrode 14 to the anode voltage Eb applied to the G4 electrode 15 V p / E
Since it is proportional to the multiplicative product of b, when adjusting the focusing of the electron beam to change VP, the degree of concentration of the two electron beams on the phosphor screen changes, and the static focusing characteristics change depending on the focusing voltage. There were drawbacks.

An object of the present invention is to provide a color cathode ray tube electron gun that has little effect on the static focusing characteristics of the electron beam even if the focusing voltage applied to the electron gun changes when adjusting the focusing of the electron beam of the color cathode ray tube. It is about providing.

[Means to solve the problem]

The present invention provides an in-line electron gun that emits three electron beams on three parallel axes in the same plane and accelerates and focuses them. Apertures on the three parallel axes are formed in the electrode closing surface, and both outer apertures have long sides or long axes in the direction in which the three apertures are arranged, and are oriented toward the central aperture side. 1. A color cathode ray tube electron gun, characterized in that a sloped portion having either a rectangular shape or an elliptical shape with increasing depth is formed, and each of the sloped portions includes respective openings drilled on both outer sides.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view including three electron gun axes showing the configuration of an in-line electron gun according to an embodiment of the present invention, and FIG. 2 is an example of the focusing electrode indicated by the arrow A-A' in FIG. 3A and 3B are enlarged cross-sectional views of the outside and the vicinity of the central opening, respectively.

As shown in FIGS. 1 to 3 (A) and (B), the in-line type electron gun 2 has electrode structures that are insulated from each other and are spaced apart from each other at equal distances So. Axis 2OR, 2
Three cathode structures 11 arranged in a line in the same plane including 0G and 20B, and G1 electrodes 12 facing them and sequentially arranged in the electron beam traveling direction. G2 electrode 13. Consists of a G3 electrode 24°, a G4 electrode 25, and a shielding magnetic pole 16. Although each electrode except the shielding magnetic pole 16 is not shown, it is fused and fixed to an insulator support rod through each electrode support part, and a predetermined electrode spacing is maintained. is held. The G3 electrode 24, which is a focusing electrode, consists of two closed cylindrical bodies 2 whose open end sides are overlapped with each other.
41.242, G3 electrode 24, G2 electrode 1
Parallel axes 2OR, 2 of the electron gun are on the closed surface opposite to 3.
0G.

Three apertures 24R1, 24Gt, 2481 are centered on 20B and are formed at equal distances 1lliSo, and the apertures 24R on both outer sides thereof.

24B1 is formed with rectangular inclined portions 24S each having a long side in the arrangement direction of the three holes and a short side larger than the hole diameter, and becoming deeper toward the central hole 24Gl side. Rectangular inclined part 2
4S can be formed, for example, by crushing the plate thickness of the hole portion using a press. However, the center of the long side of the rectangular inclined portion 24S is offset outward from the center of the openings 24R1 and 24Bt, and the distance Sl between the center and the central electron gun axis 20G is slightly larger than the above-mentioned So.

On the other hand, the openings 25R and 25G of the G4 electrode 25.

The distance S2 between 25B and 25B is also set to be somewhat larger than the above-mentioned So. That is, the relationship between the shaft distances is Sl, S2>
So. Therefore, G1 electrode 12. G2 electrode 1
3. Each opening 12R through which the electron beam of the G3 electrode 24 passes
, 12G, 12B.

13R, 13G, 13B; 24R,, 24G1.

24B! and 24R2, 24G2. Parallel paths 2OR and 20G pass through each corresponding opening of the G2 electrode 13.

It is accelerated to move above 20B.

G2 electrode 13 in FIGS. 3(A) and (B). G3 electrode 241
As shown in the enlarged sectional view near the opening, the central electron gun shaft 20G
Nearby, the opening 13G.

The equipotential line group 24PC formed at 24G1 is formed axially symmetrically with respect to the axis 20G, and the electron beam travels straight on the axis as shown by the arrow. On the other hand, 2OR on the outer electron gun axis
(20B), the rectangular inclined portion 24S is inclined outward with respect to the closed surface of the G3 electrode 241, and the center 20SR (203B) of the long side of the rectangle is eccentrically outward with respect to the axis 2OR (20B). Opening parts 13R (13B), 24R
1 (24Bt), especially the equipotential line on the 24R1 (24B1) side has an inclined surface eccentric to the center of the aperture, so that its center of curvature is aligned with the electron gun axis 2.
With respect to OR, it moves toward the solid axis 20G side and loses axial symmetry. Therefore, the electron beam advances from the electron gun axis 2OR with a slight inclination toward the central electron gun axis 2OG side as shown by the arrow.As in the past, the axes of both outer openings 25R and 25B of the G4 electrode 25 are aligned with the central electron beam. Outside of the gun shaft 20G (S2-3o)
Therefore, a non-axisymmetric electric field is formed in both outer lens parts of the main electron lens formed in each corresponding aperture gap between the G3 electrode 24 and the G4 electrode 25, and the electron beams on both outer sides are centered. Focus and concentrate on the electron beam side at the same time.

As mentioned above, the two outer main electron lenses have axes 2OR, 2
The electron beams on both sides are incident on the axis 20G with a slight inclination instead of on 0B, and the focusing sensitivity decreases with respect to changes in the focusing voltage VP.0For example, focusing voltage V,
When becomes higher than the optimum value, the lens electric fields 24Pc and 24Ps between the G2 electrode 13 and the G3 electrode 24 become stronger,
Therefore, the concentration of both outer electron beams increases, but conversely, the lens electric field between the G3 electrode 24 and the G4 pole 25 weakens, and the concentration of both outer electron beams decreases.
If the focusing voltage VF becomes lower than the optimum value, the opposite effect to that described above will occur. In other words, the degree of concentration of the electron beam between the G2-03 electrodes and between the G3-G4 electrodes is in a mutually canceling relationship with respect to increases and decreases in the focusing voltage, and the focusing sensitivity to the focusing voltage decreases significantly, causing Eliminates concentration fluctuations in the electron beam.

Moreover, by appropriately selecting the value of the axis spacing distance S,, S2 for So, or by appropriately setting the slope of the rectangular slope, it is possible to completely eliminate the concentrated fluctuation with respect to the fluctuation of the focused voltage. Become.

As mentioned above, in this embodiment, the G2 electrode 1 of the G3 electrode 24
A rectangular inclined portion 24S is provided in both outer openings drilled in the closed surface facing 3, and the center of the oblique shadow is eccentric to the side opposite to the central electron gun axis. is not eccentric to the electron gun axis, so when assembling the electron gun structure through each electrode hole and passing the vertical jig core rod, at least the G3 electrode 24 has a core that completely fits into the hole. Since the rod can be passed through, the assembly accuracy of the electron gun assembly can be maintained at all compared to the conventional method. Furthermore, since the rectangular inclined portion is formed on the G3 electrode 24, the eccentricity Δ5 of the main electron lens
2=S2-8o can be made smaller than the conventional value, reducing the axisymmetricity of the main electron lens due to eccentricity, the aberration of the main electron lens is smaller than before, and the focusing characteristics of the electron lens are improved. This makes it possible to significantly improve the resolution of electronic lenses.

FIG. 4 is a bottom view of a focusing electrode showing another embodiment of the present invention.

In the above embodiments, the center of the orthogonal shadow of the rectangular inclined portion is eccentric with respect to both outer openings, but it is not necessary to make it eccentric, or the inclined portion shape is not rectangular. , an oval shape including both outer openings, or an elliptical shape as shown in FIG.
It goes without saying that this embodiment is also applicable to a delta type electron gun that emits two electron beams on three parallel axes at the vertices of a triangle.

〔Effect of the invention〕

As described above, according to the present invention, the slope of the rectangular inclined portion formed in both outer openings of the focusing electrode closing surface facing the G2 electrode, or the center of both outer openings drilled at the center thereof. Decreasing the focusing sensitivity of the three electron beams to fluctuations in the focusing voltage by making the electron beam eccentric with respect to the electron beam, or
It becomes possible to maintain a constant level of concentration. Furthermore, since the eccentricity of the rectangular inclined portion is made eccentric with respect to the center of the aperture containing this, the aperture centers of the G2 and G3 electrodes do not need to be eccentric as in the conventional case, and the jig core is placed in the aperture. The assembly accuracy when assembling the electron gun through the rod does not deteriorate, and since sloped parts are formed in both outer openings of the G3 electrode, the opening for concentrating the electron beam in the main electron lens part The eccentricity can be made smaller than before, the aberration due to the non-axial symmetry of the main electron lens becomes smaller than before, the focusing characteristics of the electron lens are improved, and the resolution of the electron lens can be improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view including three electron gun axes showing the configuration of an in-line electron gun according to an embodiment of the present invention, and FIG. 2 is an example of the focusing electrode indicated by the arrow A-A' in FIG. 3(A) and 3(B) are enlarged cross-sectional views of the outside and near the central opening; FIG. 4 is a bottom view of the electric flux electrode showing another embodiment of the present invention; The figure is a sectional view of an example of a conventional in-line electron gun. 11... Cathode structure, 12... G1 electrode, 13...
G2 electrode, 14.24.34...G3 electrode, 15.2
5...G4 electrode, IOR, LOG, 10B, 2OR. 20G, 20B...Electron gun shaft, 20SR, 203B
...Central axis of rectangular inclined part, 30SR, 30SB...
- Central axis of elliptical inclined part, 24S... rectangular inclined part,
34 S...Elliptical inclined part, 24Pc, 24ps
...Equipotential lines. To the substitute *JJI Shinuchihara Shingyu! mouth cow S diagram

Claims (1)

[Claims] In an in-line electron gun that emits three electron beams on three parallel axes in the same plane and accelerates and focuses them, G is the focusing electrode opposite to the G2 electrode, which is the accelerating electrode.
Apertures on the three parallel axes are formed in the three-electrode closing surface, and both outer apertures have long sides or long axes in the direction in which the three apertures are arranged, and are oriented toward the center aperture. 1. A color cathode ray tube electron gun, characterized in that a sloped portion having either a rectangular shape or an elliptical shape is formed, and each sloped portion includes respective openings bored on both outer sides.