JPS5885256A - Cathode-ray tube - Google Patents

Abstract

PURPOSE:To realize a bright beam spot, and enhance the beam-spot characteristic of a cathode-ray tube by making a cathode to have a linear shape, and making an electron beam to provide a laminar flow in one direction and to form a cross over in the direction perpendicular to said direction. CONSTITUTION:The cathode 2 of a cathode-ray tube 1 is made to have a linear shape. A main electron lens 7 consisting of the first and the second electron lenses 6a and 6b, is constituted of two-dimensional lens with a spherical aberration coefficient (Cs) being small in only one direction, for example, the linear direction The linear cathode 2 consists of a coil cathode with, for example, a width of 80mum and a length of 800mum. The first, the second and the third grids 3-5 are constituted in such a manner that linear electron beams form a cross- over in its linear direction to have a divergence angle and that it makes a laminar flow with an almost zero divergence angle in the direction perpendicular to its linear direction. Owing to the above constitution, the beam-spot characteristic of the cathode-ray tube 1 can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube suitable for use in, for example, television receivers, and in particular, is capable of improving beam spot characteristics.

Various attempts have been made to reduce the spherical aberration of the electron lens used in cathode ray tubes in order to form microspots with low distortion in cathode ray tubes, but no significant progress has been made. .

Here, the spherical aberration of this electron lens will be explained using FIG.

In the electron lens Lk, since the angle of incidence of the electron beam that enters the peripheral edge is large, the degree of refraction of the electron beam is also large. This is different from the point P8 where the paraxial electron beam that passes near the optical axis of the lens L gathers. obey [
, the electron beam incident on the electron lens LK may not be at one point P, but rather form a circular spot with a radius on the A-A plane. This is the ball TM111 of the electron lens L.
This is due to the difference. The radius of this spot can be expressed as a function of the spherical aberration coefficient Cg of the electron lens L and the divergence angle of the electron beam as shown in the following equation.

L = cg・0・・・・・・・(
1) C8: Spherical aberration coefficient of electron lens L -: Divergence angle of electron beam As is clear from equation (1), in order to reduce the radius t of the spot due to the spherical aberration of electron lens L, the divergence of the electron beam is It can be seen that either the angle 0o or the spherical aberration coefficient C8 of the electronic lens L should be made small.

To reduce the divergence angle θ0 in an axially symmetrical electron beam, there is a method of making the electron beam into an inner flare. However, in this case, although the divergence angle #0 becomes small, the cathode image becomes larger than when the electron beam is 5K to form a crossover, and the beam spot becomes larger. In order to reduce the spot of this electron beam, the cathode must be made very small, which increases the load on the cathode, which is inconvenient for cathode ray tubes that require a large current.

Furthermore, as a method for reducing the spherical aberration coefficient cB of the electronic lens L, there is a means to increase the lens diameter of the electronic lens L. Increasing the lens diameter in this way increases the neck diameter of the cathode ray tube and requires a large deflection power, which is disadvantageous for cathode ray tubes.

In view of these points, the present invention is directed to eliminating the above-mentioned disadvantages and improving beam spot characteristics.

Hereinafter, one embodiment of the cathode ray tube of the present invention will be described with reference to FIGS. 2 to 10.

In Figure 2, (1) shows the cathode ray tube as a whole;
The neck of this cathode ray tube (1) has a cathode (2), a first grid (3), a second grid (4), a third grid (5) on a concentric axis, and a first electron lens (6 m). and 11
Main electron lens (7) consisting of 2 electron lenses (@b)
are respectively provided at predetermined positions. (8) is a fluorescent surface.

In the present invention, the cathode (2) of the cathode ray tube (1) is made into a linear shape, and the first and second electronic lenses (6a) are
The main electron lens (7) consisting of and (6b) is constituted by a two-dimensional lens having a small spherical aberration coefficient CB in only one direction.

The linear cathode (2) will now be explained with reference to FIGS. 3 and 4. The linear cathode (2) is composed of, for example, a width of 80 μm and a length of lIooPmf)':1 dolphin node. Both ends of this linear cathode (2) are welded to terminal pins set on the cathode supporting insulating substrate. (3) shows the first grid, which is fixed to the linear cathode (2) with a required spacing as if it were covered. . This first grid (3) has a predetermined rectangular slit (9) corresponding to one direction of the linear cathode (2). In such a linear cathode (2), a linear electron beam is generated in accordance with the linear direction of the cathode (2).

First, second and third grids (3), (4) and (5)
For a linear electron beam, a four-sover is formed in the line direction so that it has a divergence angle, and a p-sover is not formed in the direction perpendicular to the line direction and the divergence angle is small. It is constructed to be a roughly zero Laminarf helmet.

Here, we will explain the main electron lens (7) consisting of the first and second electron lenses (axes) and (6b). First, it converges in one direction and does not refract in other directions. A two-dimensional lens with a small spherical aberration coefficient in the direction of spherical aberration will be described with reference to FIG.

A two-dimensional lens can be constructed by arranging two or more electrodes, for example, three electrodes a, b, and C, on a concentric axis, as shown in FIG. That is, each electrode a, b, and C has a rectangular shape with a side ratio m:m of 2:1.
and (). In this case, the electrodes 1 and C on both sides are arranged so that the longitudinal directions of the slits 4 and f coincide with each other and are oriented perpendicularly to the slit 5, that is, in the Y-axis direction. The longitudinal direction of the slit of the electrodes located between them is arranged to be orthogonal to the longitudinal direction of the slits d and f, that is, to face the X-axis direction.In the electrodes a, b and C arranged in this way, , electrodes a and C are at the same potential s1, and electrode A is set at a potential greater than the potential d1 of electrodes Hatake and C.

The potential of this electrode is X! By adjusting , the spherical aberration can be eliminated by setting it to 5. The two-dimensional lens composed of electrodes a, b, and C configured in this way has a small spherical aberration coefficient in the X-axis direction, so that the electron beam in the X-axis direction is converged and the electron beam in the Y-axis direction is converged. does not cause refraction. The two-dimensional lens shown in FIG. 5 corresponds to the Kamabokoho lens shown in FIG. 6 in terms of optical lenses.

In this example, the first and second electron lenses (61) and (6b) are two-dimensional lenses as described above, and the first electron lens (61) is a linear lens. The second electron lens (6b
) is constructed in a two-dimensional shape with the direction of convergence being perpendicular to the linear direction of the linear cathode (2).

Note that although not shown, the horizontal deflection device, vertical deflection device, etc. may be the same as conventional ones.

Here, the linear cathode (2) as described above, the first grid (
3), 2nd grid (4), 3rd grid (5), 1st grid
The electron lens (61) and the second electron lens (6b) are shown in FIGS. The operation will be explained with reference to 8IO.

The electrons emitted from the linear cathode (2) are the first,
The second and third grids (3) (4) and (5) form a predetermined electron beam into the first and second electron lenses (6).
In the X-axis direction, the linear electrons emitted from the cathode (2) enter the main electron lens (7) consisting of the main electron lens (7) consisting of the first .m) and (6b). The second and third grids (3), (4) and (5) are formed into linear electron beams that form a K''C quadrupole and have a divergence angle, and the first and second electron lenses (6m) and (6b) K is incident. Electrodes aeaaa similar to electrodes a, b, c of 5th lIl
Because the first electron lane (6 m) is composed of a two-dimensional lens whose convergence direction is the X-axis direction.

This first electron lens (6a) K can converge the electron beam without being affected by spherical aberration. The electron beam refracted by passing through the first electron lens (61) passes through the second electron lens (6b) without being refracted and collides with the fluorescent surface (8) (Fig. 9). ,reference). In addition, in the Y-axis direction, the cathode (2
) is formed into a 27-naf electron beam at @1, Jllz, and the third grid (3), (4), and (5), which does not form a Coos opa and has a divergence angle of approximately zero. and second electron lenses (61) and (6b) K
It is incident. At this time, the electron beam passes through the first electron lens (61) without being refracted. Electrode α9α
4) Since the second electron lens (6b) is composed of a two-dimensional lens whose convergence direction is in the Y-axis direction due to Q51, the second electron lens (6b) has spherical aberration. The electron beam can be focused without being affected by the Therefore, the electron beam is refracted by passing through this second electron lens (6b) and impinges on the fluorescent surface (8) (see FIG. 10).

As described above, according to the present invention, since the cathode is made linear, a linear electron beam is generated from the cathode and is converged to obtain a beam spot, so that a very bright beam spot is obtained. be able to. In addition, the electron beam in one direction is a magnetic flux, and since it combines an electron beam that forms a beam deflection in the direction perpendicular to the negative flow, and a two-dimensional lens with a small spherical aberration coefficient a in one direction, the axial It is possible to obtain a small beam spot that is not affected by aberrations, which cannot be obtained by combining a symmetrical beam and an axially symmetrical lens. In this way, since a very bright yet small beam spot can be obtained, the beam spot quality can be improved. Furthermore, since the cathode is in the form of a wire, the load can be reduced compared to when used as a point cand, and it is also suitable for use in cathode ray tubes that require a large current.

However, in the above embodiment, an electrode having a rectangular slit was used to construct the two-dimensional lens.
A two-dimensional lens can be constructed by arranging two or more pairs of parallel plate electrodes of 2iIIIc facing each other. or,
Although the second electron lens (6b) is also constructed as a two-dimensional lens, it is easily understood that this second electron lens (6b) may also be constructed as an axially symmetrical lens similar to the conventional one. I can understand. It goes without saying that the present invention is not limited to the above-described embodiments, and that various other configurations can be adopted without departing from the gist of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the spherical aberration of the I electron lens, Fig. 2 is a schematic diagram showing an embodiment of the cathode ray tube of the present invention, and Figs. 3 and 3 are plane views of the cathode shown in Fig. 4 is a side sectional view of FIG. 3, FIGS. 5 and 6 are block diagrams each showing a two-dimensional lens theory, and FIGS. 7 and 8 are each an implementation of the cathode ray tube of the present invention. 9 and 10, which are cross-sectional views of the main parts of the example, are diagrams for explaining FIGS. 7 and 8. (1) is a cathode ray tube, (2) is a linear cathode, (3),
(4) and (5) are respectively 1st. The second and third grids, (7) are main electron lenses, and (8) are fluorescent surfaces. 7th r::i ^ 2nd rc>J 3rd Figure 9Z Figure 10 et al. Application No. 183509 2, Title of the invention Cathode ray tube 3, Relationship with the case of the person making the amendment Patent applicant residence:・i8) Sony Corporation Representative Director Kazuo Iwama 4, Representative 1-8 Nishi-Shinjuku, Shinjuku-ku, Tokyo (
Shinjuku Building) Tokyo (03) 343-5821 (Representative)
6. Number of inventions increased by amendment 7. Supplementary IE (1) Subject Pengming's detailed explanation column and brief explanation column of drawings in the specification and drawings (1) In the specification, page 2, No. 14 Row r L = Cs
−θ♂・・・・・・(1)” is replaced with “t −cB・0♂
...(1)" is corrected. (2) Same, page 4, line 11, ``main electron lens (7) in one three directions'' is replaced with ``main electron lens (7) in one direction K, for example, linear direction K''. correct. (3) Ibid., p. 5, 1 [lines 15-16 “No refraction...
・Correct the phrase ``small spherical aberration coefficient'' to ``divergent.'' (4) Same, page 6, lines 12 to last line “This electrode...
This corresponds to Correct the word J as follows. ``By selecting the potential in this way, the electron beam in the X direction converges, and the electron beam in the Y axis direction diverges.Furthermore, 1
Although not shown, electrodes having the same shape as these three electrodes are rotated by 90 degrees around two axes K, and electrodes /, b/, and cI are placed in the positive direction of the Z axis with a predetermined distance apart, and electrodes a'
, c' have the same potential φIK as electrodes a and c, and electrode b' has the same potential as φ2'. Electrode field configured like this #
The two-dimensional lens group consisting of be '# "# b'l" focuses the electron beams on the same point in the X-axis and Y-axis directions by adjusting the potentials φ2゜φ2' of the electrodes b and b'. It is possible to achieve convergence and have a small spherical aberration coefficient in the X-axis direction. In terms of optical lenses, the two-dimensional lens shown in FIG. 5 corresponds to a convex lens in the X-axis direction and a concave lens in the Y-axis direction. (5) Same, page 7, line 15, ``Figures 7 and 8'' is corrected to ``Figure 6 and Figure 7 J.'' (6) Same, page 8, lines 8 to 8. Line 11: “It consists of...
・Can converge. ” It says, “Configure, electrode C
131α4α9 constitutes a second electron lens (6b) as a two-dimensional lens button with the X-axis direction as the direction of divergence. ” is corrected. (Power Ibid., same page, line 12, ``refracted'' is corrected by JK, ``converged.'' (9) Same, same page, line 14, “(See Figure 9)” has been replaced with “
(See Figure 8)”. Ql) Same page, line 19 to line 9jj, line 8, "At this time, the electron beam... collides (see Figure 10)." [At this time, this first electron lens (61 ), the electron beam is converged by the second electron lens (6b), passes through, and collides with the same point on the fluorescent surface (8) as mentioned above (see Figure 9). ). ”K corrects. aυ Same, page 11, lines 1 to 2, "Figures 5 and 6 are respectively".
The third line of the same person and the fifth line of the same page, ``Figures 7 and 8'' have been corrected to ``Figures 6 and 7''. (13fif1. On the 4th line of the same page, "Figures 9 and 10" is corrected to "Figures 8 and 9." Figures 7 and 8 are corrected to Figures 6 and 7 as indicated in red on the attached sheet. αe Same, Figures 9 and 10 are corrected to It!8 and Figure 9, and corrected as shown in the attached sheet. That's it.

Claims (1)

[Claims] The cathode is linear, and the electron beam generated from the skeleton cathode is made to have a laminar flow in a direction perpendicular to the linear direction of the cathode, and a crossover is formed in the linear direction of the cathode. , and the configuration of the main electron lens is such that the aberration is small in the linear direction of the cathode! ! #Cathode ray tube with mold.