JPS5840752A - 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 three beams are concentrated with the magnetic-focusing device itself, by providing each of opposed magnetic yorks with at least independent three cylindrical parts, and making the distance between the side cylinders of the magnetic york on the screen side larger than the distance between the axes of electron guns. CONSTITUTION:Opposed magnetic york 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, 54'. The cylindrical parts 53 and 54 of the magnetic york 52 on the negative electrode side coincide with the center axes of three electron guns which are determined by a cathode and a control electrode, while the side bylinders 54' of the magnetic york 52' on the screen side are apart from the axes of the electron guns which are determined by the above cathode and control electrode by a given distance (DELTAX) toward the outside. 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 is curved toward the axes of the side cylinders 54' of the york 52'. As a result, a magnetic field formed between the yorks 52 and 52' has outward components on 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 electron beam focusing means, but the magnetic focusing method provides a higher degree of resolution. In addition, the magnetic focusing method does not require the supply of a focus voltage, which improves the reliability of the cathode ray tube.
There are major benefits such as lower stress. In the method using a special heat permanent magnet as a magnetic field generation source, no focusing power is required.

FIG. 1 is an example of a magnetically focused m cathode ray tube having multiple electron beams. (1) is a glass envelope that keeps the inside vacuum, (2) is an outer neck, (3 凰), (&i)
, (3m) are the heater, cathode, first . An electron gun assembly consisting of a second electrode, (4) a phosphor screen, (5) a color selection electrode, (6).

(6') are soft ferromagnetic magnetic yokes facing each other, (7
m), (7・)-(7m) are the electron gun structures (
3 凰), (&l).

(3m) is the trajectory of the electron beam emitted from the beam, (8) is the deflection yoke, and (9) is the three-electron beam concentrator. A permanent magnet (not shown) for generating a magnetic field is disposed at the mouth of the tube. Electron gun (
3m)-(3o)-(3m)
7).

(7g) = (7m) 11 Opposing L magnetic m-p
(6), (6') The tube axis direction magnetic field formed between the tubes receives a focusing effect and focuses the smallest beam spot on the screen (4). Furthermore, in order to concentrate the child beams on the side beams (7m) and (7m) using the concentrator (9),
) is deflected in the direction of the center beam (7.) to perform three beam concentration. However, in such an electron beam concentration method, the beam spot on the screen becomes vertically elongated, which is undesirable.

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

Figure 11s2 shows permanent magnets placed above and below the center beam. Figure 2 fa) is the cross-sectional shape of the neck (
21), (21G), and (2b) are three electron beam passing holes, @ is a permanent magnet having an elongated direction in the tube axis direction, and is placed at a predetermined position above and below - of the center beam five passing hole. Ru. 2nd m (b) and (c) are Y-Y in Figure 2(a)
' and xx' cross-sectional shapes are shown. In FIG. 2, the explanation will be given assuming that the two axes are tube axes and that there is a screen in the 2+ direction. The permanent magnet @ is magnetized so that the end face in the 21 direction is the N pole (the end face in the 2+ direction is magnetized as the S pole).The magnetic field lines that emit the N pole in the vertical section (Fig. 2(b)) are magnetically affected (2 ) passes through the inside and leaks at the gap between the opposing magnetic yoke (23') and forms a 2+ direction focused main magnetic field, which leads to the magnetic side (23').
However, it is difficult to completely shape the magnetic field, and in reality there is a magnetic field that originates from the north pole and goes in one direction to infinity, and a magnetic field that enters the south pole from 2 + infinity. The same thing occurs in the horizontal section, i.e. in Fig. 2 (C1) the main magnetic field is affected by the magnetic interference (
To), (formed in the 2+ direction between 23 but 1ifi!
There is a 2-direction ζ 2-count magnetic field from the -ri@ end and a magnetic field from 2+ toward the magnetic eye (2f). Figure 2(d) shows an outline of the magnetic field distribution on the axis of the side beam hole (Zlm), where B is a component that gives a deflection effect to the beam. Third
In the diagram (Ji), four permanent magnets 01) are arranged 42 times above and below near the side beam passage holes (32m)-(32m). This configuration is similar to the above-mentioned B!
The acid component and deflection magnetic field component decrease.

Furthermore, as shown in FIG. 3(b), (as shown in C1, three beams are arranged before and after the permanent magnet C) (by setting the common yoke to a predetermined length ζ2), and the above-mentioned deflection component is By changing the shape of the magnetic mesh, the arrangement of the permanent magnets, etc., it is possible to form a magnetic field that has almost no deflection component, so that it can be significantly reduced to 0 or more.

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 (41m)
, (41o) -<41m> is incident on the magnetic yoke (end) and the magnetic gap section through which there is almost no deflection component, as described above. The main magnetic field in the magnetic contact gap (b) is directed in <z+ (screen) direction as shown in the figure, and has an outward magnetic field component at a predetermined angle O with respect to the beam traveling direction on (41m)-(41s). BX
to include. Of course, the electron beam (41
, ), there is only a magnetic field in the mu direction.

The force exerted on the beam at this time is shown in FIG. 4(b).

The velocity of the electron beam is only Ma1, and due to the above Bx, (
At 41, the force is applied in the Y- (T) direction, and at (411), the force is applied in the Y+ (upward) direction. Therefore, after passing through the magneto-acoustic gap, the electron beam (41m) will be in the Y, (T) direction,
The electron beam (41B) has a velocity component in the y+ (upward) direction. The cathode (neck end) (2-) and the stomach (to) placed on the screen side (2+), (4
2') has an asymmetrical shape, that is, the cathode IIM-
The mechanism has sufficient length in two directions to obtain a sufficiently uniform magnetic field, and the screen side (4! is of a predetermined length. Therefore, Fig. 114 Ta) In the B-B' cross section, Magnetic field shielding and shaping are weak because Bx acid components remain. FIG. 4(C) is an explanatory diagram of the force exerted on the beam in the B-B' cross section.

As mentioned above, the electron beam (41m) at this cross section is
and -V. On the other hand, the magnetic field has -Bl and -Bx.

Therefore, the force exerted on the beam is Fl−ma m x (Bx)
eFy ” (=vy) X (Bx) receives forces in one direction of X and in the direction of Y+.
4ha) obtains the speed in the X direction and the speed in the Y direction. The Y direction velocity cancels out the Y direction velocity component received at the h-A' cross section, and as a whole, the Y direction velocity component is zero and only the X direction velocity component remains. Beam in reverse position (4
Similarly, in h), the velocity component in the X direction is obtained. 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. 6tJ is a 3-beam common magnetic coil arranged on the cathode side (to), (52 is an opposing magnetic coil according to the present invention, and (51 is a screen side magnetic quadrupler) .Opposing magnetic yokes according to the present invention■.

Since (52') has three beam independent cylindrical parts (to), 64, (53'), and (54') on surfaces facing each other, this cylindrical part has a magnetic ring (to) on the cathode side. ), the center axis of the three electron guns is determined by the cathode and control electrode, whereas in the screen side magnetic yoke (52'), both side cylinders (54') are aligned with the electron gun axis determined by the cathode and control electrode. The axis is deviated outward by a predetermined value Δxfe.

In the magnetic field shaped by the magnetic yoke IJ (52) having such a shape, the lines of magnetic force advance so that the magnetic resistance becomes small, so the magnetic field is bent in the direction away from the axis of the screen side magnetic yoke (52').As a result, The magnetic field formed between the magnetic yoke 153° (52) has an outward component at the side cylinder (54).Of course, if the polarity of the permanent magnet is reversed, the magnetic field will be reversed.Cathode side Magnetic beams can be used as long as the internal magnetic field is sufficiently uniform and the beam is practically not deflected. The magnetic ring (51) may be of any type as long as its height and shape control the deflection component of the screen-side leakage magnetic field to a predetermined value.

As described above, the effect on the three beams of the magnetic eye applied to the present invention is as explained using FIG. 4, and detailed explanation thereof will be omitted. In addition, in the present invention, by changing the above-mentioned off-axis amount ΔX, the magnetic field inclination angle can be changed appropriately, so the three-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 can be obtained even when the cylindrical portions are formed inside the opposing magnetic yokes.

As described above, according to the present invention, three-beam concentration is performed by the magnetic focusing device itself, and a magnetic focusing 11M1Ik polar ray device that is easy to use and highly reliable can be provided by making the most of the advantages of the magnetic focusing method.

[Brief explanation of drawings]

The first factor is a schematic configuration diagram showing an example of a magnetically focused cathode wrapped tube device; b) to (dl and 3B!0(b) to (C) are also schematic diagrams for explaining the neck side view and magnetic field distribution, and 49CI (M) to (C) are detailed explanations of the present invention. Fig. 5 is a schematic horizontal sectional view showing a magnetic sealing portion according to an embodiment of the present invention. Beams (42), (42'), (43), (43-・
・Magnetic yoke - Magnetic yoke gap part (51), (51')... Common magnetic yoke (52)
, (5τ)... Opposite magnetic yoke (53), (53
'), (54), (54...cylindrical part (7317
) Agent: Patent Attorney Noriyuki Chika (and 1 other person) No.
1 Figure 2 (z2:)
(b) Figure 3 Figure 4 (IL)

Claims (1)

[Scope of Claims] l) A glass envelope, an electron gun enclosed within the neck of the envelope and equipped with a control means for emitting three electron beams arranged in-line, and an electron gun provided on the inner surface of the envelope panel. A cathode ray tube mainly composed of a coated fluorescent surface and a shadow mask disposed near the fluorescent surface, and a permanent magnet for generating a magnetic field in the tube axis direction and a magnet for shaping the magnetic field as means for focusing the electron beam. In a magnetically focused cathode ray tube device equipped with a yoke, the magnetic lobes facing each other have at least three independent cylindrical portions, and the cylindrical portion has an O magnetic field at an end side of the neck portion. In the field, it coincides with the three electron gun axes determined by the cathode and control electrode, and in the screen side magnetic yoke, the spacing between the cylinders on both sides is larger than the spacing between the electron gun axes. Magnetic focus cathode ray tube device. 2) A pair of opposing magnetic sounds from the cathode that emits the electron beam - In the area where the electron beam is emitted, the radial magnetic field component on the axis of the side beam is as small as possible, and the pair of opposing magnetic sounds -
The magnetic field according to claim 1, characterized in that the tortoise = magnetic eye is made asymmetrical in the front and back so that a predetermined radial magnetic field component is formed on the five axes of the side beam between the side beam and the screen. Focused m-logic sight tube device.