JPH05303943A - Inline type electron gun for color picture tube - Google Patents

Abstract

PURPOSE:To prevent deflection of static convergence due to fluctuation of a focus voltage, achieve high resolution, and provide a more favorable image quality in an inline type electron gun for a color picture tube employing self- convergence system. CONSTITUTION:An inner electrode 30 provided with diagonally cut cylindrical protruding edges 302R, 302B which are coaxial with center axes of both outer side electron beam passage holes 141R, 141B at an end surface of an acceleration electrode 13 of a focusing electrode 14, and which is of a cylindrical form of which forward end part is of a diagonally cut form to be higher as it becomes closer to a center of a tube axis is provided inside the focusing electrode 14. Because refraction action of an inclination potential formed by effects of the cylindrical protruding edges 302R, 302B offsets refraction action of both outer side electron beams 17R, 17B at a main electron lens, deflection of static convergence by fluctuation of a focus voltage can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-line color picture tube electron gun, and more particularly to an in-line color picture tube electron gun having excellent convergence characteristics.

[0002]

2. Description of the Related Art In order to increase the resolution of a color picture tube, three electron beam spots are formed over the entire screen.
It is necessary to focus on the points. Conventionally, in a general color picture tube provided with an in-line type electron gun in which three electron beam emitting portions are arranged side by side in the same plane in the horizontal direction, the horizontal deflection magnetic field distribution is pincushion-shaped and the vertical deflection magnetic field distribution is vertical. A so-called self-convergence method is adopted in which three electron beams can be concentrated at any point on the screen by combining deflection magnetic fields in which the deflection magnetic field distribution is distorted in a barrel shape. In the in-line type electron gun, various methods of concentrating both outer electron beams at the center of the screen have been devised and incorporated in order to correct static convergence.

FIG. 5 is a sectional view of an example of a conventional bi-potential focus type in-line electron gun.

As shown in FIG. 5, the in-line type electron gun has three cathodes 11R, 11G and 11B, a control electrode 12 and an accelerating electrode 1 which are arranged side by side in a horizontal direction.
3, the focusing electrode 14 and the final accelerating electrode 15 are arranged so as to have a predetermined interval in the traveling direction of the electron beam.
Each electrode has an electron beam passage hole corresponding to each of the three electron beams. The control electrode 12 has electron beam passage holes 121R, 121G, 121B, and the acceleration electrode 13 has electron beam passage holes 131R, 131G. 131B, electron beam passage holes 141R, 141G, 141B on the end surface of the focusing electrode 14 on the acceleration electrode 13 side, and electron beam passage holes 143R, 14 on the end surface of the focusing electrode 14 on the final acceleration electrode 15 side.
3G, 143B, electron beam passage holes 151R, 151G, 151B on the end surface of the final accelerating electrode 15 on the focusing electrode 14 side.
Has been drilled.

Final accelerating electrode 1 through which the central electron beam passes
The central axis Z _15G of the central electron beam passage hole 151G of FIG.
Central electron beam passage holes 121G, 131G, 141G,
It is coaxial with the central axis Z _14G common to 143G, and both central axes Z _14G and Z _15G substantially coincide with the tube axis of the color picture tube. Final accelerating electrode 15 through which both outer electron beams pass
The central axes Z _15R and Z _15B of both outer electron beam passage holes 151R and 151B are
131R, 141R, 143R and 121B, 131
The central axes Z _14R and Z _14B common to B, 141B and 143B are eccentric by an eccentric amount d toward the outer side of the tube axis.

FIG. 6 is a horizontal cross-sectional view showing the equipotential distribution of the main part of the bi-potential focus type in-line electron gun shown in FIG. 5 when a predetermined operating voltage is applied.

Generally, the cathodes 11R, 11G and 11B are 90 to 120 v, the control electrode 12 is Ov, and the acceleration electrode 13 is.
Is applied from the outside with a focus voltage of 6 to 7 kv to the focusing electrode 14 and an anode voltage of about 25 kv to the final accelerating electrode 15. The main electron lens for focusing the electron beam is an electron beam passage hole 143R arranged so that the focusing electrode 14 and the final accelerating electrode 15 face each other.
-151R, 143G, 151G, 143B, 151B
Formed in between.

The main electron lens which focuses the central electron beam 17G is an equipotential line 20 which is axisymmetric about the central axes Z _14G and Z _15G.
The central electron beam 17G travels straight on the central axes Z _14G and Z _15G due to the axially symmetric lens formed by 1 and 21 1.
On the other hand, the main electron lens that focuses both outer electron beams 17R and 17B is an equipotential line 2 which is axisymmetric about the central axes Z _14R and Z _14B.
02 and the central axes Z _14R and Z _14B are non-axisymmetrical lenses formed from equipotential lines 212 that are eccentric to the central axes Z _15R and Z _15B that are eccentric in the tube axial outer direction by an eccentric amount d.
The outer electron beams 17R and 17B traveling straight on the central axes Z _14R and Z _14B are the central axes Z _15R and Z of the equipotential line 212.
_It will pass through the part from _{15B in the} direction of the pipe axis, and will receive a concentration force in the same direction.

Therefore, the three electron beams 17R, 17
G and 17B are concentrated at the center point on the screen (not shown), and so-called static convergence correction is performed.

[0010]

In the color picture tube having the in-line type electron gun as described above with reference to FIG. 6, the final adjustment of the convergence is performed after the focus voltage is set so that the resolution is best in the entire screen. However, the following problems occur due to variations in focus voltage settings.

When the focus voltage V _F applied to the focusing electrode 14 becomes as high as (V _F + ΔV _F ), the potential difference between the focusing electrode 14 and the final accelerating electrode 15 becomes small and the strength of the main electron lens becomes weak, so that the strength of the main electron lens becomes weak. The force for refracting the electron beam in the tube axis direction is weakened, and the concentration of the electron beams on both outer sides is reduced. On the other hand, when the focus voltage V _F applied to the focusing electrode 14 becomes as low as (V _F −ΔV _F ), the potential difference between the focusing electrode 14 and the final accelerating electrode 15 increases, and the strength of the main electron lens increases. The force for refracting the electron beam in the tube axis direction increases, and the concentration of the electron beams on both outer sides increases.

Therefore, the strength of the formed main electron lens changes with respect to the fluctuation of the focus voltage, so that the power for refracting the outer electron beams changes, resulting in a problem that the static convergence is deviated.

As described above, the resolution of the color picture tube is deteriorated and the image quality is extremely deteriorated.

An object of the present invention is to provide an electron gun for an in-line type color picture tube which has a high resolution and an excellent image quality.

[0015]

SUMMARY OF THE INVENTION According to the present invention, a central electron beam and cathodes for emitting both outer electron beams, which are arranged in a straight line at least approximately perpendicular to the tube axis direction, are arranged in sequence in the traveling direction of the electron beam. A control electrode, an acceleration electrode, a focusing electrode, and a final acceleration electrode, and the final acceleration of the focusing electrode is made with the central axis of both outer electron beam passage holes of the end surface of the final acceleration electrode on the focusing electrode side. In an electron gun for an in-line type color picture tube, which is eccentric in the tube axis outer direction with respect to the central axis of both outer electron beam passage holes of the electrode side end surface,
Inside the focusing electrode, an inner electrode having a central electron beam passage hole and both outer electron beam passage holes having a cylindrical protruding edge or a U-shaped side wall having an opening in the tube axis outer direction is provided. The cylindrical protruding edge or the "U" -shaped side wall having an opening in the tube axis outer direction is provided so as to face the acceleration electrode side end surface direction of the focusing electrode, and By forming a slanted shape whose height increases as the shape of the tip becomes closer to the center of the tube axis, it is possible to form a gradient potential to reduce the deviation of the static convergence due to the fluctuation of the focus voltage. And

[0016]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a sectional view of the first embodiment of the present invention, and FIG. 2 is a perspective view of the internal electrodes of the focusing electrode of FIG.

In the first embodiment, as shown in FIG. 1, the focusing electrode 14 is provided with an internal electrode 30 as shown in FIG.

The internal electrodes 30 are electron beam passage holes 141R, 141G, 1 on the end surface of the focusing electrode 14 on the acceleration electrode 13 side.
Three circular electron beam passage holes 301R, 30 are formed so as to be coaxial with the central axes Z _14R , Z _14G , Z _{14B of} 41B.
1G and 301B are provided on one common surface, and both outer electron beam passage holes 301R and 301B have a slanted cylindrical protruding edge whose height increases toward the center of the tube axis. This is an electrode structure having 302R and 302B. Therefore, by providing the inner electrode 30 so that the cylindrical protruding edges 302R and 302B face the end surface of the focusing electrode 14 on the accelerating electrode 13 side, both outer electron beam passage holes 141 are formed.
The distance from R, 141B to the cylindrical protruding edges 302R, 302B gradually becomes longer as the distance from the tube axis is reduced so that the minimum distance l _{1 is on} the tube axis center side and the maximum distance l ₂ is on the side opposite to the tube axis. ing.

FIG. 3 is a horizontal sectional view showing the equipotential distribution of the main part of the first embodiment shown in FIG. 1 when a predetermined operating voltage is applied.

As shown in FIG. 3, the equipotential line 221 formed in the central electron beam passage hole 141G on the end face of the focusing electrode 14 on the acceleration electrode 13 side is axisymmetric with respect to the central axis Z _14G . , Both outer electron beam passage holes 141R, 141
The equipotential line 222 formed in B is formed from the outer side electron beam passage holes 141R and 141B to the cylindrical protruding edges 302R and 30R.
In the part from the center on the tube axis side where the distance to 2B is short,
Since it strongly suppresses the entry of the low potential from the accelerating electrode 13, it has an obliquely non-axially symmetric shape with respect to the central axes Z _14R and Z _14B .

Therefore, the central electron beam 17G travels straight in the central electron beam passage hole 141G, whereas the outer electron beams 17R and 17B have a concentrated force in the tube axis direction at both outer electron beam passage holes 141R and 141B. receive. This means that the tilt potential formed by the influence of the cylindrical projecting edges 302R and 302B is equal to that of the both outer electron beams 1.
It means that it has a refraction effect on 7R and 17B.

Therefore, when the focus voltage V _F applied to the focusing electrode 14 becomes as high as (V _F + ΔV _F ), the refracting action in the tube axis direction is weakened in the main electron lens and the outer electron beams 17R and 17B are concentrated. But the focusing electrode 1
In both outer electron beam passage holes 141R and 141B of No. 4, the relative potential difference with respect to the accelerating electrode 13 becomes large, so that the refraction action of the inclined potential formed by the influence of the cylindrical protruding edges 302R and 302B becomes strong and the both outer electrons are The concentration of the beams 17R and 17B increases. On the other hand, the focusing electrode 14
When the focus voltage V _F applied to the lens becomes as low as (V _F −ΔV _F ), the refraction in the tube axis direction becomes stronger in the main electron lens and the concentration of both outer electron beams 17R and 17B increases, but the focusing electrode 14, both outer electron beam passage holes 141
In R and 14B, the relative potential difference with respect to the accelerating electrode 13 becomes smaller, so that the refraction action of the inclined potential formed by the influence of the cylindrical protruding edges 302R and 302B becomes weaker, and the concentration of both outer electron beams 17R and 17B decreases. To do.

Therefore, with respect to the fluctuation of the focus voltage,
Main electron lens portion and both outer electron beam passage holes 141R, 1
Since the refraction effects of the outer electron beams on both sides in 41B work in such a manner that they cancel each other in the opposite directions, the deviation of the static convergence can be extremely reduced after all.

FIG. 4 is a perspective view of the internal electrodes of the focusing electrode according to the second embodiment of the present invention.

In the internal electrode 30 of the first embodiment shown in FIG. 2, the tip shape is a slanted tubular protruding edge whose height increases as it goes from the center of the tube axis side. The internal electrode 40 of the second embodiment has an opening in the outer side of the tube axis, and has a slanted shape in which the height increases as the tip shape becomes closer to the center of the tube axis. Side wall 303R,
It is an example of the electrode structure having 303B, and it goes without saying that the same effect as that of the first embodiment can be obtained even with such a structure.

In the above-mentioned embodiment, the bi-potential focus type in-line type electron gun has been described. However, the present invention is not limited to this. For example, a multi-stage focusing type focus gun is used. It goes without saying that the same effect can be obtained even when applied to an in-line type electron gun.

[0028]

As described above, according to the present invention, the height becomes higher inside the focusing electrode as it faces the direction of the end surface of the focusing electrode on the side of the accelerating electrode and the shape of the tip becomes closer to the center of the tube axis. By providing an internal electrode with a cylindrical protruding edge or a U-shaped side wall forming a slanted shape in both outer electron beam passage holes, the refraction action of the tilt potential formed by the inner electrode is performed. By canceling out the refraction action of the electron beams on both sides in the lens, it is possible to extremely reduce the deviation of the static convergence due to the fluctuation of the focus voltage, and it is possible to obtain a high resolution and an excellent image quality.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

2 is a perspective view of an internal electrode of the focusing electrode of FIG. 1. FIG.

3 is a horizontal cross-sectional view showing the equipotential distribution of the main part of the first embodiment shown in FIG. 1 with a predetermined operating voltage applied.

FIG. 4 is a perspective view of internal electrodes of a focusing electrode according to a second embodiment of the present invention.

FIG. 5 is a sectional view of an example of a conventional bi-potential focus type in-line electron gun.

6 is a horizontal cross-sectional view showing the equipotential distribution of the main part of the bi-potential focus type in-line electron gun shown in FIG. 5 when a predetermined operating voltage is applied.

[Explanation of symbols]

11R, 11G, 11B cathode 12 control electrode 13 acceleration electrode 14 focusing electrode 15 final acceleration electrode 17R, 17G, 17B electron beam 30, 40 internal electrode 121R, 121G, 121B, 131R, 131G,
131B, 141R, 141G, 141B, 143R,
143G, 143B, 151R, 151G, 151B,
301R, 302G, 303B Electron beam passage holes 201, 202, 211, 212, 221, 222
Equipotential lines 302R, 302B Cylindrical protruding edges 303R, 303B U-shaped side walls Z _14R , Z _14G , Z _14B , Z _15R , Z _15G , Z _15B
Electron beam passage hole central axis d Eccentricity l ₁ , l ₂ Distance to cylindrical protruding edge

Claims (2)

[Claims] 1. A cathode for emitting a central electron beam and both outer electron beams, which are arranged in a straight line at least substantially perpendicular to the tube axis direction, a control electrode sequentially arranged in the traveling direction of the electron beam, and an acceleration electrode. A focusing electrode and a final accelerating electrode, and the central axes of the electron beam through holes on both sides of the focusing electrode side end surface of the final accelerating electrode pass through both outside electron beams of the focusing electrode side end surface of the final accelerating electrode. In an electron gun for an in-line type color picture tube which is eccentric with respect to the central axis of the hole, in the direction outside the tube axis, inside the focusing electrode, a central electron beam passage hole and both outer electron beams having a cylindrical protruding edge are provided. An inner electrode having a passage hole is provided, the cylindrical protruding edge is provided so as to face the direction of the end surface of the focusing electrode on the side of the acceleration electrode, and the shape of the tip end thereof is closer to the center of the tube axis. The higher the height An in-line color picture tube electron gun characterized by a slanted shape that makes it look like 2. A cathode that emits a central electron beam and both outer electron beams, which are arranged in a straight line at least substantially perpendicular to the tube axis direction, a control electrode that is sequentially arranged in the traveling direction of the electron beam, and an acceleration electrode. A focusing electrode and a final accelerating electrode, and the central axes of the electron beam through holes on both sides of the focusing electrode side end surface of the final accelerating electrode pass through both outside electron beams of the focusing electrode side end surface of the final accelerating electrode. In an in-line type color picture tube electron gun that is eccentric to the central axis of the hole in the tube axis outer direction, a central electron beam passage hole and an opening in the tube axis outer direction are provided inside the focusing electrode. "
An inner electrode provided with both outer side electron beam passage holes having a U-shaped side wall, wherein the U-shaped side wall is provided so as to face the acceleration electrode side end face direction of the focusing electrode, and An electron gun for an in-line type color picture tube, characterized in that its tip portion has a beveled shape whose height increases as it goes from the center of the tube axis side.