JPS5840751A - Magnetic-focusing-type cathode-ray tube - Google Patents

Abstract

PURPOSE:To obtain an excellent magnetic-focusing-type cathode-ray tube, which has a high reliability and in which concentration of three beams is peformed with the magnetic-focusing device itself and the magnetic-focusing system is made the most use of, by making magnetic yorks to be assymmetrical relative to their center line so that given radial field components are formed on side beams. CONSTITUTION:Opposed magnetic yorks 52 and 52' have cylindrical parts 53, 54 and 53', 54', which face to each other, so that each of three beams passes through a different pair of cylindrical parts 53, 53' or 54, 55'. The length of the center cylinder 53 of the magnetic york 52 on the negative electrode side is larger than that of the side cylinders 54, while the length of the center cylinder 53' of the york 52' on the screen side is shorter than that of the side cylinders 54'. The cylinders of the york 52 and the cylinders of the york 52' face to each other with a given distance allowed between them. Since the line of magnetic force travels so that magnetic resistance becomes the minimum, a magnetic field formed with the yorks 52 and 52' with such shapes tends to concentrate on the center cylinder 53 in the york 52, and tends to concentrate on the side cylinders 54' in the york 52'. As a result, a magnetic field formed between the yorks 52 and 52' has outward components on the axes of the side cylinders 54 and 54'.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetically focused cathode ray tube device having multiple electron beams.

There are both electrostatic focusing methods and magnetic focusing methods as focusing means for electron beams, but the magnetic focusing method provides a higher degree of resolution. Furthermore, the magnetic focusing method does not require the supply of a focus voltage, and has associated great advantages such as improved reliability and reduced cost of the cathode ray tube. In the method using a permanent magnet as a magnetic field generation source, no focusing power is required. FIG. 1 shows an example of a magnetically focused cathode ray tube containing a plurality of electron beams. (1) is a glass envelope that keeps the inside vacuum, (2) is the envelope neck (3B), (3G), (311
) are respectively the heater, the jump pole, and the first. Electron gun structure consisting of a second electrode, (4) a fluorescent screen, (5) Fi color selection electrode, (6), (chains are soft ferromagnetic magneto-acoustic wires facing each other, (7B), ( 7G) and (γB) are the electron gun structures (3 vines), respectively.

(3G), the electron beam trajectory emitted from (311), (
8) is a deflection yoke, and (9) is a three-electron beam concentrator. A permanent magnet (not shown) for generating a magnetic field is placed within the tube. The electron beams (7B), (7G), (7B) emitted from the electron guns (3B), (3G), (311) face nine magnetic yokes (6).

(The minimum beam spot tm is formed on the screen (4) due to the focusing effect of the tube axial magnetic field formed between (7B) and (7m) are deflected toward the center beam (7G) to perform three-beam concentration. However, in this electron beam concentration method,
The beam spot on 41 becomes vertically elongated, which is not preferable.

The present invention provides a 5-magnetic focusing cathode ray tube device that performs self-focusing using a focusing magnetic field. In order to simplify the explanation of the present invention, a conventional example will be explained in further detail.

#! Figure 2 shows permanent magnets distributed above and below the center beam. Figure 2 (a) shows the cross-sectional shape of the neck (2
11L), (21G), and (21B) are three electron beam passing holes, and 0'l is a permanent magnet whose longitudinal direction is in the tube axis direction, and is placed at a predetermined position above and below the center beam passing hole (21G). be done. Figures 2(b) and (c) are similar to Figure 2(a).
It shows YY' and xx' cross-sectional shapes of t.

In FIG. 2, the explanation will be given assuming that the Z axis is the tube axis and that there is a screen in the Z+ direction. The end face of the permanent magnet in the Z direction is magnetized to the N pole, and the end face in the Z+ direction is magnetized to the 8 poles. The magnetic field lines emitted from the N pole in the vertical cross section (Figure 2) pass through the inside of the magnetic yoke (to) and leak out at the gap between the magnetic yoke 1 and the opposing magnetic yoke, forming a main magnetic field focused in the middle direction. is absorbed and returns to the S pole.

However, it is difficult to completely shape the magnetic field, and in reality there is a magnetic field that originates from the t'i N pole and goes to an infinite distance in two directions, and a magnetic field that enters the Z pole from an infinite distance to the 8 poles. The same thing happens for horizontal sections. That is, in FIG. 2(c), the main focusing magnetic field is the magnetic yoke (c).

A magnetic field is formed in the Z10 direction in the d-opening, but there is a magnetic field directed in the 2nd direction from the end of the magnetic yoke portion, and a magnetic field directed toward the magnetic yoke from Z+. FIG. 2) schematically shows the magnetic field distribution on the axis of the side beam hole (21&), and Bx is a component that gives a deflection effect to the beam. Figure 3 (a) Fi permanent magnet 0υ
Four of them are placed above and below near the sideby person passage hole (32") t (30). This configuration is shown in Fig. 2 (a).
), the above-mentioned Bx acid component and deflection magnetic field component are reduced.

Furthermore, in Fig. 3(b), there is a common yoke (b) that surrounds the three beams in front and behind the permanent magnet C31 (as shown in cl).
By setting the above-mentioned deflection component to a predetermined length, the above-mentioned deflection component can be significantly reduced. As described above, depending on the shape of the magnetic yoke, the arrangement of the permanent magnets, etc., it is possible to form a magnetic field with almost no deflection component.

The present invention further allows three beams to be focused in a magnetic focusing device having almost no deflection magnetic field component as described above.

The present invention will be explained in detail below.

FIG. 4 is a diagram showing the principle of the present invention. Electron beam (41B)
, (41G), and (41B) enter the magnetic yoke gap S (Incorporated) through the magnetic yoke ring and the inside of the lock, which have almost no deflection component, as described above. Magnetic yoke gap (
The main magnetic field in the magnetic field is Z+ (screen) as shown in the figure
The beam is oriented in the direction (4xm) and (41it) so that it has a predetermined angle θ with respect to the beam traveling direction and includes an outward magnetic field component Bx. Of course, the electron beam (41G
), there is only a magnetic field in the Viz+ direction. The force that Bea A receives at this time is shown in FIG. 4(b). The speed of the electron beam is V
z only (II) and the above Bx (41B), YL
It receives a force in the FiY+ (upward) direction at (41b) in the (downward) direction. Therefore, after passing through the magnetic yoke gap, the electron beam A (41B) faces YL (downward), and the electron beam (4
1b) It has a velocity component in the FiY+ (upward) direction.

Cathode (neck end) side (L) and screen side (Z+)
The yoke -9- disposed on the side has an asymmetrical shape. That is, the cathode side yoke (6) has sufficient length in two directions to obtain a sufficiently uniform magnetic field, and the screen side yoke (2) has a predetermined length. Therefore, in the cross section aJB-B' in the m4 diagram, the magnetic field is shielded and the shaping is weak (Bx acid components remain).

FIG. 4(c) is an explanatory diagram of the force applied to the beam in the HB' cross section. As mentioned above, the electron beam (41B) in this cross section has Vg and -vy. On the other hand, the magnetic field is -Bz
and -Bx.

Therefore, the force that the beam receives is Px = Vz
B") sFY" (-Vy) X (-Bx
) receives forces in one direction of p, X and Y+ force.

Therefore, electron beam (41B) $1, X unidirectional velocity and Y
Ten direction velocity 1f, t- is obtained. The Y+ direction velocity cancels out the Y direction velocity component received at the AA' cross section, and as a whole, the Y direction velocity component is zero and only the X direction velocity component remains. Similarly, for the beam (41B) in the opposite position, KX+
Obtain the directional velocity component. As described above, both side beams receive a concentration effect in the direction of the center beam.

FIG. 5 is a horizontal sectional view of a magnetic yoke portion according to an embodiment of the present invention. 6D is a 3-beam common magnetic yoke disposed on the cathode side, aa is a ring, and 6D is a magnetic yoke facing each other according to the present invention;
υ is the magnetic field on the screen side. The opposing magnetic yoke rings i according to the present invention have cylindrical portions 0.64, aj, and a411t on mutually opposing surfaces: three beams independently.

This cylindrical part has a center cylinder length longer than both side cylinder lengths in the cathode side magnetic seeker, and conversely, the screen side magnetic seeker has a center cylinder length longer than both side cylinder lengths.
In case i, the center cylinder length is shorter than both side cylinder lengths, and they face each other with a predetermined interval. In the magnetic field shaped by one wheel of magnetic yoke having such a shape, the lines of magnetic force advance in such a way that the magnetic resistance is minimized, so in the magnetic yoke ring, the magnetic field tends to concentrate on the center cylinder, and in the case of six magnetic yoke wheels, the magnetic field tends to concentrate on the side cylinder ( As a result, the magnetic field formed at the magnetic yoke has an outward component at the side cylinder 64 and 641 portions. Naturally, if the polarity of the permanent magnet is reversed, the opposite will occur. The cathode side magnetic yoke 6D is not limited to the magnetic yoke common to the three beams, as long as the magnetic field therein is sufficiently uniform and the beam is practically not deflected. Also, the screen side magnetic eye 6
6 can control the deflection component of the leakage magnetic field on the screen side to a predetermined value by its height and shape.'/''0 As described above, the effect of the magnetic yoke applied to the present invention on the three beams is as follows. This is a general description using FIG. 4, and detailed explanation will be omitted.

Oka, the present invention allows the magnetic field angle tube to be changed appropriately by changing the ratio of the center and side cylinder lengths.
The beam concentration effect can also be set appropriately, and its versatility is wide and manufacturing is easy.

It goes without saying that the same effect is obtained even when the cylindrical part is formed inside the opposing magnetic yoke.

As described above, according to the present invention, three beams are concentrated by the magnetic focusing device itself, and a good and reliable magnetic focusing cathode ray device can be provided that takes full advantage of the advantages of the magnetic focusing method.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a magnetically focused cathode ray tube device, FIG. 2 (Ill) and FIG. )) to)
and Figures 3 and 3) to (cl are the same side views of the neck and schematic diagrams for explaining the magnetic field distribution, and Figures #! 4 (a) to (c).
) are a side view and a sectional view for explaining the present invention in detail,
FIG. 5 is a schematic horizontal sectional view showing a magnetic yoke portion according to an embodiment of the present invention. (41 凰), (41G)', (41m)...Electron beam (42), (42'), (43), (43')...
・Magnetic yoke (44)...Magnetic gap part (51), (51')...Common magnetic sound ri (52)
), (52') ... Opposite magnetic field (53),
(53'), (54), (54')... Cylindrical part (73
17) Representative Patent Attorney Noriyuki Chika (and 1 other person) ＼ Figure 2 (2 and)
Box. Figure 3 Figure 4 (tL)

Claims (1)

[Scope of Claims] 1) A glass envelope and a control means for emitting and controlling three inline/arrayed electron beams sealed in the neck of the envelope and an electron gun and an inner surface of the envelope panel. The main feature is the coated fluorescent surface and the shadow mask placed near the fluorescent surface. In a magnetically focused W cathode ray tube device which is a cathode ray tube configured as an element and is equipped with a permanent magnet for generating a magnetic field in the tube axis direction and a magnetic yoke for shaping the magnetic field as a focusing means for the electron beam, the magnetic The yoke has at least three independent cylindrical parts, and the cylindrical parts are arranged so that the height of the center cylinder is higher than the height of the cylinders on both sides in the case of magnetic sound on the end side of the neck part. A magnetically focused cathode ray tube device characterized in that the yoke is formed such that the height of the center cylinder is lower than the height of the cylinders on both sides. 2) A pair of opposing magnetic sounds from the cathode that emits the electron beam - In the region where the 2-sial magnetic field component on the side beam axis is as small as possible, t + the pair of opposing magnetic sounds -
The magnetic sound beam is asymmetric between the front and rear so that a predetermined radial magnetic field component is formed on the side beam axis between the side beam axis and the screen.
The magnetically focused cathode ray tube device described in 2.