JPS5840750A - 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 performed with the magnetic-focusing device itself, by making a magnetic field, which develops between opposed magnetic yorks and is in the direction of the tubular axis, to be at a given angle from the tubular axis on the side-beams passing positions. CONSTITUTION:Electron beams 41B, 41G and 41R, after passing through magnetic yorks 42 and 43 which have almost no deflection comonents, become incident upon a magnetic-york gap. The main magnetic field is directed toward the Z+ direction (screen) on the magnetic-york gap as illustrated in the figure, and made to have an outward magnetic component slanting a given angle (theta) from the traveling direction of the beam on the beams 41R and 41B. The electron beam 41R is given a speed in the (X-) direction and a speed in the (Y+) direction, which is neutralized by a Y--direction speed component received by the beam 41 in the A-A' section. As a result, the beam 41R comes to have only the (X-)- direction speed component. In contrast, the beam 41B located on the oppsite side to the beam 41R obtains an (X+)-direction speed component in the same manner as above. Consequently,the side beams 41R and 41B recevie concentric effects directing toward the center beam 41G.

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, and has the accompanying great advantages of improving the reliability of the cathode ray tube and reducing costs. : In this case, no focusing power is required.

FIG. 1 is an example of a magnetically focused cathode ray tube having a plurality of electron beams. (1) is a glass envelope that maintains a vacuum inside, (2) is the neck of the envelope, (3 凰) = (3@)
-(3■) are respectively a heater, a cathode, and a first. The electron gun structure consists of a second electrode, (4) is a fluorescent screen, (5) is a color selection electrode, (61, (6)' are mutually C; ) −(7・), (7■)
are the electron gun structures (3 wisterias).

(3o), (am) The trajectory of the emitted electron beam, (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 beam (7m) - (7e) - (7m) emitted from the electron gun <3m> - (36) - (3m) is emitted from the opposing magnetic sound beam (6), (6Y between 6: the tube to be formed). The focusing effect of the axial magnetic field focuses the smallest beam spot on the screen (4).

In order to further concentrate the 3-sako beam, the concentrator (9)
is used to deflect the side beams (7m) - (7m) in the direction of the center beam (7G) to perform three-beam concentration. However, in this electron beam concentration method, the beam spot on the screen (4) It becomes vertically elongated, which is not desirable.

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. Fig. 2 shows a center beam in which upper and lower permanent magnets are arranged. Fig. 2 (a) shows the cross-sectional shape of the neck. (21m), (21o)t (21m) is a 3" can beam passing hole, (2) is a permanent magnet having a tube axis direction of 4=longitudinal direction and is a center beam passing hole (21a) 2 (b).

(C) shows the Y-Y' and x-x' cross-sectional shapes of gz diagram (a).
+ direction 6: Explained assuming that there is a screen. The permanent magnet block is magnetized with an N pole on the end face in the 2-way direction and an 8-pole end face on the end face in the 2+ direction. Vertical section Figure 2 (b) - The lines of magnetic force emitted from the N pole pass through the inside of the magnetic yoke (2) and leak at the gap between it and the opposing magnetic yoke (to), forming a main magnetic field focused in the 2+ direction. The magnetic yoke (2) (=absorbed and returns to the S pole C2. However, it is difficult to completely shape the magnetic field, and in reality, the magnetic field is emitted from the N pole and sent to infinity in one direction (2 magnetic fields and z4 limit). ) There is a magnetic field that enters the south pole.

The same thing occurs even if there are 4 horizontal sections.
2) between (:z direction C: is formed, but the magnetic field goes in one direction from the end of the magnetic yoke (to) and the magnetic yoke (
2) There is a magnetic field directed towards. FIG. 2(d) shows an outline of the magnetic field distribution on the axis of the side beam hole (21m), where the horse is the component that gives the beam C two deflection effect.

Figure 3(a) shows four permanent magnets C11), and two devices (upper and lower) near the side beam passage hole (32■) and (a2m).This configuration is the same as in Figure 2(a). Also mentioned above is B! The acid component and the deflection magnetic field component decrease (=, 3rd
As shown in )-(C), front and back ζ of permanent magnet 6D: 3
By setting the common l-couple surrounding the beam 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 that has almost no deflection component.

The present invention is a magnetic focusing device having almost no deflection magnetic field component as described above (two in number, and three beams can be focused). It is a principle diagram of the invention.

As described above, the electron beams (41), (41.), and (411) mostly pass through the magnetic 1-couple and the interior, which have no deflection components, and enter the magnetic yoke gap. The main magnetic field at the magnetic yoke gap is Z as shown in the figure.
+ (sp v −y) direction! Kak (4ts)
t (4 wt. be. The force that the beam receives at this time is shown in Figure 4)
Shown below.

The velocity of the electron beam is only M2, and it is determined by Bx mentioned above.
) (41m) receives a force in the Y-("F) direction; 12 (41b) receives a force in the Y+(g) direction. Therefore, after passing through the magnetic 1-k gap, the electron beam (41) receives a force in the Y-C)")
The electron beam (41b) has a velocity component in the Y+ (g) direction. Cathode (neck end) Mu and screen side (Z+) side C; Place Cao-ku, 91
If there are 4 of them, they will have an asymmetrical shape. That is, the cathode side yoke has sufficient length in two directions to obtain a sufficiently uniform magnetic field, and the screen side yoke has a predetermined length. For this reason,
In the cross section of FIG. 4(i) B-B', the shielding and shaping of the magnetic field is weak, and the Bx acid component remains. 841(e) is B
- It is an explanatory view of the force which a beam receives in section 62.

As mentioned above, the electron beam (41m) at this cross section is
and -v1. On the other hand, the magnetic field has −B and −B. Therefore, the force that the beam receives is 1ix==vl
-BX) t'y = (-Vy) Therefore, the electron beam (IIL) obtains a velocity in the X direction and a velocity in the Y direction. The velocity in the Y direction cancels out the velocity component in the Y direction at the Mu A' cross section, and as a whole, the velocity component in the Y direction is zero and only the velocity component in the X direction remains. Reverse position 6
Similarly, for the second beam (4h), the velocity component in the X direction is obtained.

As described above, both side beams will receive a concentrated effect in the direction of the center beam. Horizontal concentration is magnetic field inclination θ
The vertical concentration can be corrected by the shape of the magnetic yoke at the B-8' cross section.

The formation of the main magnetic field with an inclination angle can be carried out in various ways as follows. FIG. 5 shows permanent magnets having different end surfaces in the longitudinal direction, and are arranged above and below the center beam. Further, as shown in FIG. 6, the magnetization may be performed using a radial magnetization field. Also, when using four permanent magnets, C2 is #
This can also be carried out by tilting the permanent magnet at a predetermined angle with respect to the tube axis 1, as shown in Figure I7. Naturally, by combining the various embodiments of the permanent magnet described above with a predetermined magnetic yoke configuration, that is, with a negligible deflection component on the incident side and a predetermined deflection component on the output side, the present invention This is carried out in various ways.

As described above, according to the present invention, the magnetic focusing device itself focuses 3 beams from 42, takes full advantage of the magnetic focusing method, and provides a good and reliable magnetically focused cathode ray tube device. Can do 0

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an example of a magnetically focused cathode ray tube device, Figs. ) to (d)
3) to (C) are the same side views of the neck and schematic diagrams for explaining the magnetic field distribution, and Fig. 4 (1) to (C)
1 is a rounded side view and sectional view for explaining the present invention in detail, and FIGS. 5 to 7 are schematic diagrams showing an example of a permanent magnet to which the present invention is applied. (41B)-(41・)*(41m)...Electron beam action-d, u, ta'...Magnetic yoke-...Magnetic yoke gap (7317) Patent attorney Noriyuki Chika ( 1 person) Figure 2 tAノ ,,I
:,. Figure 3 (cL) (Mu) (c) γ- Figure 5 Between Figure 6 and Figure 7 B&R

Claims (1)

[Scope of Claims] 1) A glass envelope and a neck portion of the envelope (two enclosed electron guns that emit three electron beams in an in-line arrangement and are equipped with a control means, nine electron guns, and the envelope panel); A cathode ray tube configured as an element having a fluorescent surface coated on the inner surface and a shadow mask disposed near the fluorescent surface, which includes a permanent magnet for generating a magnetic field in the tube axis direction and a magnetic field as means for focusing the electron beam. A magnetically focused cathode ray tube device equipped with a shaping magnetic yoke: = between the opposing magnetic yokes (the generated magnetic field in the tube axis direction has a predetermined angle with the tube axis direction at the position where both side beams pass). A magnetic focusing device characterized in that the extension line intersects the tube axis at the end side of the neck portion (: none), and the beam traveling direction and the magnetic field are parallel to each other at the central beam passing position (; type cathode ray tube device. 2) The permanent magnets for generating the magnetic field are arranged in groups of at least four permanent magnets, and each of the permanent magnets is arranged at a predetermined angle with respect to the tube axis direction. The magnetically focused cathode ray tube device according to claim 1, characterized in that the magnetic field in the beam passage section has a predetermined inclination angle with respect to the tube axis 1. 3) At least two permanent magnets for generating the magnetic field are used. Each of the permanent magnets is characterized in that its longitudinal cross section is different on the front and back, or that it is magnetized by a radial magnetic field 62 centered at a predetermined position outside the permanent magnet in the longitudinal direction. The magnetically focused cathode ray tube device according to claim 1. 4) The magnetic yoke is asymmetric at least in the front and back), and at least the electron beam is incident on the side beam axial radial magnetic field component. is as small as possible and has a predetermined value on the emission side of the electron beam.
4. A magnetically focused cathode ray tube device according to items 3 to 3.