JPH04104434A - Electron gun for in-line type color picture tube - Google Patents

Abstract

PURPOSE:To restrict deflection of convergence to the minimum and improve the focus characteristic by providing protruding edges for compensation of an electric field to concentrate A beam at a tube shaft at specified passage holes for both outer electron beams at specified end surfaces of a first and second focus electrodes. CONSTITUTION:For obtaining predetermined focus characteristics, a dynamic voltage applied to a second focus electrode 15 is increased, where concentration of both outer electron beams 17R, B become insufficient at a main electron lens part between the electrode 15 and a final acceleration electrode 16, but a refraction effect is increased by an inclined potential formed by flat protruding edges 142R, B at outer electron beam passage holes 141R, B of a first focus electrode 14 at a quadruple lens part. The refraction effects of both outer electron beams thus act to offset each other in the main electron lens part and the quadruple lens part for fluctuation of the dynamic voltage, and deflection of convergence can be restricted to the minimum, and thereby deterioration of resolution can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an in-line color picture tube electron gun,
In particular, the present invention relates to an in-line type color picture tube electron gun that improves the deterioration of the shape of the electron beam slit 1 and has excellent convergence characteristics.

[Conventional technology]

In order to increase the resolution of a color picture tube, it is necessary to reduce the spot diameter of the electron beam and to concentrate the three electron beam spots to one point over the entire screen, and if either of these is the cause of deterioration. Even if you do so, the resolution will deteriorate and the image quality will deteriorate.

In a general color picture tube equipped with an in-line electron gun in which three electron beam emitting sections are arranged side by side in the same horizontal plane, the horizontal deflection magnetic field distribution 1 is as shown in Fig. 5<a). 5 (b
), three electron beams 1.7B, 17G, and 17R can be concentrated at any point on the screen by combining the deflection magnetic field in which the vertical deflection magnetic field distribution 2 is distorted into a barrel shape. It's coming. It uses a so-called self-convergence method.

However, when an electron beam passes through the above-mentioned self-convergence deflection magnetic field, it is not affected by the distortion of the magnetic field and is not deflected.If the electron beam spot, which was circular at the center of the screen, is deflected to the periphery of the screen. This results in a distorted electron beam shape with a horizontally elongated beam core 3 and radial halos 4 above and below the beam core 3, as shown in FIG. In other words, if the diameter is made small at the center of the screen and the focus voltage is maintained at the optimum level to obtain a perfectly circular electron beam spot, the periphery of the screen will be overfocused in the vertical direction compared to the horizontal direction, resulting in a halo in the vertical direction. It becomes easier. Therefore, the diameter of the distorted electron beam at the periphery of the screen is larger than that of the circular electron beam at the center of the screen, which significantly degrades the resolution at the periphery of the screen.

Various proposals have been made as methods for improving the shape of the electron beam around the screen using the self-convergence deflection magnetic field described above. For example, Japanese Patent Application Laid-open No. 61-99249 discloses three cathodes 11R11G11, B, a control electrode 12, an accelerating electrode 13, a first focusing electrode 24, which emit three electron beams, as shown in FIG. Second focused electric current 1ji15. It consists of a final accelerating electrode 16 and a second focusing electrode f! of the first focusing electrode 24. There is a vertically elongated electron beam passage hole 241 on the end face on the 15 side.
R, 241G, 241B, and the second focusing electrode 15
A horizontally elongated electron beam passing hole 151 is provided in the end face on the first focusing electrode 24 side, a constant first focus voltage is applied to the first focusing electrode 24, and a deflection angle of the electron beam is applied to the second focusing electrode 15. With the increase in horizontal deflection as shown in Figure 8,
By applying a dynamic voltage of, for example, a parabolic waveform synchronized with vertical deflection, a quadruple diameter lens 5 as shown in FIG. 9 is formed between the first focusing electrode 24 and the second focusing electrode 15.
A diverging force is applied to the electron beam 17 in the vertical direction, and a converging force is applied in the horizontal direction to offset the distortion of the electron beam caused by the self-convergence magnetic field. A method for obtaining the spot diameter has been proposed.

[Problem to be solved by the invention]

In a typical color picture tube equipped with an in-line electron gun, in which three electron beam emitters are arranged side by side in the same horizontal plane, the three emitted electron beams are focused on one point at the center of the screen. In order to By decentering the central axis in an outward direction away from the tube axis with respect to the central axis on the focusing electrode side, a non-axisymmetric main electron lens is formed and both outer electron beams are refracted in the tube axis direction.

By the way, the color picture tube electron gun described in Japanese Patent Application Laid-Open No. 61-99249, which cancels out the distortion of the electron beam shape due to the self-convergence deflection magnetic field as shown in FIG. The second focusing electrode 15 is intended to obtain a predetermined focusing characteristic by applying a dynamic voltage to the second focusing electrode 15.
When the voltage applied to the main electron lens is increased, the potential difference between the second focusing electrode 15 and the final acceleration type '$fi 16 becomes smaller, so that the strength of the main electron lens becomes weaker. Therefore, the force for refracting the electron beams on both sides in the direction of the tube axis is weakened, and the concentration of the electron beams on both sides becomes insufficient. Therefore, on the screen, there is a pattern in which the convergence of the three electron beams is consistent at the center of the screen, but they become separated as they move away from the center of the screen. If the three electron beams cannot be focused on one point over the entire screen, color streaks will occur, which will degrade the resolution and extremely degrade the image quality.

[Means to solve the problem]

The in-line color picture tube electron gun of the present invention comprises at least a cathode for emitting a central electron beam and both outer electron beams arranged in a straight line almost perpendicular to the tube axis direction, a control electrode, an accelerating electrode, and a first focusing electrode. electrode, a second focusing electrode, and a final acceleration electrode; A vertically elongated electron beam 13 passage hole is provided on the end face of the focusing electrode on the second focusing electrode side, and
A horizontally elongated or circular electron beam passing hole is provided on the end surface of the second focusing electrode on the first focusing electrode side so as to face the electron beam passing hole, and a constant focusing voltage is applied to the first focusing electrode. , in an in-line color picture tube electron gun which is driven by applying a dynamic voltage to the second focusing electrode to cancel the distortion of the electron beam due to the deflection magnetic field, the second focusing electrode side of the first focusing electrode; Of the electron beam passing holes provided on the end face of the second focusing electrode and the end face of the second focusing electrode on the first focusing electrode side, and through which the electron beams on both sides pass, at least one opposing electron beam passing hole has both outer sides. A protruding edge for electric field correction is provided to concentrate the electron beam toward the tube axis.

〔Example〕

Next, the present invention will be explained with reference to the drawings. FIG. 1 shows the first part of the in-line color picture tube electron gun of the present invention.
1 is a perspective view of an embodiment of the invention. In order to simplify the explanation, the same parts as those described above are given the same reference numerals in the following explanation. The end surface of the first focusing electrode 14 on the second focusing electrode 15 side has vertically elongated electron beam passing holes 141R, 1, 41, G, 1.
．． 41B, of which both outer electron beam passing holes 1'1: 1, through which both outer electron beams pass.
On the outside of R141B away from the tube axis, flat projecting edges 142R and 142B for electric field correction are provided.

FIG. 2 shows a state in which, in this embodiment, a constant first focus voltage is applied to the first focusing electrode 14, and a dynamic voltage higher than the first focus voltage is applied to the second focusing electrode 15. FIG. 3 is a horizontal cross-sectional view of the main part showing the equipotential distribution. The equipotential lines 201 formed in the central electron beam passing hole of the first focusing electrode]4]G are symmetrical with respect to the horizontal direction, while the outer electron beam passing holes 1, 4.1, R, 141B are symmetrical in the horizontal direction. Equipotential lines 20 formed in
2 has a strong function of suppressing the insertion of high potential from the second focusing electrode 15 in the portions of the flat protruding edges 1, 42R, , 1, 42B, so the shape is obliquely inclined as shown in FIG. I will do it. Therefore, the central electron beam 17G emitted from the cathode 1.1G travels straight through the central electron beam passage hole 141G of the first focusing electrode 14, whereas the central electron beam 17G emitted from the cathode 1.1G
, both side electron beams 1, 7R, 1 emitted from IIB
7B is the electron beam passage hole 141R, 1, 4, 1 on both sides.
It receives (and concentrates) a bending force in the direction of the tube axis at B.

Therefore, as described above, when the dynamic voltage applied to the second focusing electrode 15 is increased, the refraction effect in the tube axis direction is weakened in the main electron lens section between the first focusing electrode 15 and the final accelerating electrode 16, and electrons on both outer sides are weakened. Although the concentration of the beams 17R, 1, and 7B is insufficient, both outer electron beam passing holes 141, R, 1, 41, and B of the first focusing electrode 14 of the quadruple-like lens portion are flat-shaped projecting edges 142R, The refraction effect is strengthened by the gradient potential formed by 142B, and the electron beam 1 on both sides is
．． The concentration of 7R and 17B increases. Therefore, when the dynamic voltage changes, the refraction effects of the electron beams on both sides in the main electron lens section and the quadruple-like lens section cancel each other out in opposite directions, so that when the dynamic voltage is applied, Discrepancies in convergence can be extremely reduced, and resolution does not deteriorate significantly.

FIG. 3(a) is a perspective view of a quadruple diameter lens section showing a second embodiment of the present invention. In the first embodiment shown in FIG. 1 described above, the horizontally elongated electron beam passing hole 151 of the second integrated electrode 15 was one electron beam passing hole spanning three electron beams; Two independent horizontally elongated electron beam passing holes 151R, 151G, and 151B,
Further, electron beam passing holes 141 on both sides of the second focusing electrode 15
Since the force of refraction in the tube axis direction is concentrated not only at the electron beam passing holes 151 and R and 151B on both sides of the second focusing electrode 15, but also at the electron beam passing holes 151 and R, 151B on both sides of the second focusing electrode 15, Similarly to the embodiment, the deviation in convergence when a dynamic voltage is applied can be extremely reduced.

In addition, in FIG. 3(a), the protruding edges for electric field correction are flat, but as shown in the third embodiment of FIG. 4, electron beam passing holes on both sides of the first focusing electrode 14, 141R, 1, 41B
The projecting edge 142R142B is a cylindrical projecting edge whose height decreases as it approaches the tube axis, and the electron beam passing holes 151R, 151 on both sides of the second focusing electrode 15 are
, B, the same effect can be obtained even if the projecting edges 152R, 1, 52B are cylindrical projecting edges whose height decreases as the distance from the tube axis increases.

In addition, in the second and third embodiments shown in FIG. 3 (a> and FIG. 4), the protruding edges for electric field correction were provided on both the first focusing electrode side and the second focusing electrode side. It goes without saying that the same effect can be obtained even if only one of them is used.

〔Effect of the invention〕

As explained above, the present invention provides an electron beam that is provided on the end face of the first focusing electrode on the second focusing electrode side and on the end face of the second focusing electrode on the first focusing electrode side, and through which both electron beams pass. At least one of the opposing electron beam passing holes is provided with a protruding edge for correcting the electric field to concentrate the electron beams on both sides toward the tube axis, so that an electric field is applied to the second leaf bundle electrode. This has the effect of extremely minimizing convergence deviations due to dynamic voltage fluctuations, resulting in better focus characteristics.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a first embodiment of an in-line color picture tube electron gun of the present invention, FIG. 2 is a horizontal sectional view of the main part of the first embodiment shown in FIG. 1, and FIG. (a) is a perspective view of the quadruple diameter lens portion of the second embodiment of the present invention, and FIG. 3(b) is a horizontal sectional view of the main part of the second embodiment shown in FIG. 3(a). , FIG. 4 is a perspective view of the quadruple diameter lens portion of the third embodiment of the present invention, and FIG. 5 (a>
, (b) is a polarization magnetic field distribution diagram of the in-line self-convergence method, and FIG. 6 is a diagram showing the distortion pattern of the electron beam spot due to the deflection magnetic field in FIGS. 5(a) and (b).
Figure 7 is a perspective view of a conventional in-line color picture tube electron gun, Figure 8 is an example of an optimal dynamic voltage applied to the second focusing electrode, and Figure 9 is a diagram of a quadruple diameter lens. It is. 1... Horizontal deflection magnetic field distribution, 2... Vertical deflection magnetic field distribution, 3... Beam core, 4... Halo, 5... Quadruple diameter lens, IIR, IIG, IIB... Cathode, 12 Control electrode, 13・Acceleration electrode, 14.24...First focusing electrode, 141R, 141G, 1.41B, 241G, 24
1B...Vertical electron beam passing hole of first focusing electrode, 14
2R, 142B...Protruding edge, 15/Second focusing electrode, 1
51B, 1, 51R, 151G. 151B...second focusing electrode horizontally elongated electron beam passage hole;
152R, 152B... projecting edge, 16... final acceleration electrode, 1.7.17R, 17G, 17B... electron beam, 201, 202, 211, 212... equipotential line.

Claims (1)

[Claims] 1. At least a central electron beam and a cathode for emitting both outer electron beams arranged in a straight line substantially perpendicular to the tube axis direction, a control electrode, an accelerating electrode, a first focusing electrode, and a second focusing electrode. a final acceleration electrode, a vertically elongated electron beam passage hole is provided on the end surface of the first focusing electrode on the second focusing electrode side, and the electron beam passing hole is provided on the end surface of the second focusing electrode on the first focusing electrode side. A horizontally elongated or circular electron beam passing hole is provided opposite to the beam passing hole, a constant focusing voltage is applied to the first focusing electrode, and the distortion of the electron beam due to the deflection magnetic field is canceled out to the second focusing electrode. In an in-line color picture tube electron gun that is driven by applying a dynamic voltage that causes An in-line color picture tube electron gun characterized by being provided with a protruding edge for electric field correction to concentrate the beam toward the tube axis. 2. The electron beam passing hole through which both outer electron beams pass through the end face of the second focusing electrode on the first focusing electrode side is also provided with a protruding edge for electric field correction to concentrate the outer electron beams toward the tube axis side. 2. The in-line color picture tube electron gun according to claim 1, wherein: 3. Claim 1 or 2, wherein the protruding edge for electric field correction has a flat plate shape.
The described in-line color picture tube electron gun. 4. The in-line color picture tube electron gun according to claim 1 or 2, wherein the projecting edge for electric field correction is cylindrical.