JPS5935499B2 - cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube, and more particularly to a cathode ray tube having a structure in which mesh electrodes are removed.

In a conventional post-acceleration cathode ray tube, the electron beam emitted from an electron gun is deflected vertically or horizontally and then accelerated by a post-acceleration electric field formed by a flat or curved mesh and a post-acceleration electrode on the inner wall of the bulb. By this,
It is configured to obtain a spot of increased brightness on the fluorescent screen.

However, this type of cathode ray tube has disadvantages in that the mesh deteriorates spot resolution and electron gun efficiency, and that secondary electrons hitting the mesh cause halation on the screen surface.

In order to overcome this type of drawback, there is a cathode ray tube that does not use a mesh, for example, disclosed in Japanese Patent Publication No. 31613/1982, which has a structure of two quadrupole lenses and a hemispherical electrode and eliminates the mesh.

However, this type of cathode ray tube has the disadvantage that the deflection angle becomes large, causing blurring at the edges of the screen surface and poor spot uniformity, and the disadvantage that the electron gun efficiency is worse than that using a mesh. Furthermore, there was a drawback in that two electrodes had to be additionally arranged in order to correct pattern distortion.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a meshless cathode ray tube that eliminates the above-mentioned drawbacks.

To achieve the above object, the present invention provides an electron gun (for example, the cathode 2 of the embodiment, the first and second grids 3, 4, the first
and a second anode 5, 6), the electron beam emitted from the electron gun is directed in a first direction and a second direction orthogonal to the first direction. A deflection system (for example, an electrostatic deflection system or an electromagnetic deflection system consisting of the vertical deflection plate 7 and the horizontal deflection plate 8 of the embodiment) that deflects in the direction of
at least one post-electrode provided after the deflection system; a substantially flat cylindrical electron lens disposed near the post-electrode; and a target for impacting the electron beam emitted from the electron gun. and the electron lens is substantially formed into a cylindrical shape having first, second, third, and fourth surfaces through which the electron beam can pass. a cylindrical portion having substantially first, second, third, and fourth surfaces; and a target-side opening of the cylindrical portion having a width that allows the electron beam to pass therethrough. a second electrode disposed adjacent to the first electrode and having a substantially occluded fifth surface having a slit; The end of the target side of the surface and the third surface opposite to the first surface is formed into a concave or convex shape with curvature, and the first surface of the second electrode and the first surface The electron gun side end of the opposing third surface is formed into a concave or convex shape with a curvature, and the traveling direction of the electron beam swung in the first direction by the deflection system is directed into the electron lens. The electron beam is configured to be reversed at the first slit, and the first electron beam is
This invention relates to a cathode ray tube characterized in that it is configured to produce a lens action that focuses the light in the direction of the cathode ray tube.

In the present invention, the mesh is omitted, and instead a flat electron lens in the shape of a fan-shaped box or a box is arranged, and a slit is provided on the surface of this electron lens on the target side, so that the electron beam passes through this slit. Since it is configured as
Not only is halation eliminated, but the electron gun efficiency and spot resolution are improved, and vertical blurring is reduced due to the convex lens action of the slit.

Furthermore, it is possible to improve the deflection sensitivity in the vertical and horizontal directions while suppressing spot blur.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the electrostatic focusing and electrostatic deflection type cathode ray tube for waveform observation according to the first embodiment of the present invention has a cathode 2, a first grid 3, a second grid r4, and a cathode 2, a first grid 3, a second grid r4, and a It is constructed by providing one anode 5, a second anode 6, a vertical deflection plate 7, a horizontal deflection plate 8, a two-segment fan-shaped box-shaped electron lens 9, a rear accelerating electrode 10, and a target 11 as a fluorescent display screen. .

Therefore, this cathode ray tube is not provided with a mesh electrode, but instead is provided with a two-part fan-shaped box-shaped electron lens 9.

The parts other than the two-part fan-shaped box-shaped electronic lens 9 have a known configuration C. For example, the cathode 2 has -2 KV, the first grid 3 has -2100 to -2000 V, and the second grid 4
OV is applied to the tube wall, and 12 KV is applied to the second stage accelerating electrode 10, which serves as a third anode and is made of a conductive coating provided on the tube wall.

In this cathode ray tube, an electron beam emitted from a cathode 2 enters a second grid 4 and is accelerated while the beam amount is controlled in a first grid 3.
, is focused by a unipotential lens composed of a first anode 5 and a second anode 6, and then swung vertically and horizontally by an electrostatic deflection system composed of a vertical deflection plate 7 and a horizontal deflection plate 8, and then the present invention It passes through a two-part fan-shaped box-shaped electron lens 9 and reaches a target 11.

The two-segment fan-shaped box-shaped electronic lens 9 is composed of a combination of a first electrode 12 and a second electrode 13, as shown in FIGS. 2 to 1, and is made of metal in the shape of a fan-shaped box as a whole.

Such an electronic lens 9 has a fan-shaped box shape with a gap 14.
It is obtained by cutting at the part corresponding to .

The first electrode 12 has first, second, third, and fourth surfaces 15
, 16, 17°18, and is formed into a cylindrical shape through which an electron beam can pass.

Further, the second electrode 13 has a cylindrical portion consisting of first, second, third, and fourth surfaces 19, 20, 21, and 22, and an opening on the target side of this cylindrical portion that allows the electron beam to pass through. a substantially closed fifth surface 24 having a slit 23 of a permissible width;
and is arranged adjacent to the first electrode 12.

The first and second electrodes 12 and 13 are not simply divided into two parts of a fan-shaped box-shaped body, but are the target-side ends of the first and third surfaces 15 and 17 of the first electrode 12 that are opposed to each other. 2
5 is curved toward the electron gun (cathode).

That is, the end 25 is concavely curved with a curvature like a part of a circle or a part of an ellipse.

Furthermore, the target-side ends 26 of the mutually opposing second and fourth surfaces 16 and 18 of the first electrode 12 protrude toward the target.

That is, the end 26 has a curvature like a part of a circle or a part of an ellipse and protrudes in a convex shape.

Since the second electrode 13 is adjacent to the first electrode 12 with a small gap 14 having a uniform width, the end of the second electrode 13 on the electron gun (cathode) side is adjacent to the first electrode 12. It is formed in a shape that corresponds to the end on the target side.

To explain this in detail, the electron gun (cathode) side end 21 of the mutually opposing first and third surfaces 19 and 21 of the second electrode 13 is a part of a circle or a part of an ellipse in the direction of the electron gun. It has a curvature like that and protrudes in a convex shape.

Further, the second and fourth surfaces 2 of the second electrode 13 that face each other
The end 28 on the electron gun side of 0.22 mm is concavely curved with a curvature like a part of a circle or a part of an ellipse in the direction of the target.

To give an example of the geometric size of the above-mentioned electron lens 9, in a cathode ray tube having a display screen of 8CrfL in length and 10c1rL in width, the height of the surface 24 on the target side is approximately 1.
3mm, width is approximately 35mm, width of slit 23 is approximately 6mm
, the length from the target surface 24 to the electron gun side opening 41 is approximately 42 mm, the width of the electron gun side opening 410 is approximately 20 mm, and the first
The radii of curvature of the ends 25 of the first and third surfaces 15, 17 of the electrode 13 and the ends 27 of the first and third surfaces 19, 21 of the second electrode are approximately 20 m7IL, and The radius of curvature of the ends 26 of the second and fourth surfaces 16° 18 and the ends 28 of the second and fourth surfaces 20, 22 of the second electrode 13 is approximately 10
mvt.

Next, the function of the electronic lens 9 will be explained with reference to FIGS. 8 to 11.

If an electron lens is configured by applying a voltage of, for example, OV to the first electrode 12 and a voltage of -900V to -1200V to the second electrode 13, the vibration will be generated in the vertical direction (first direction) as shown in FIG. The electron beam 29 or the electron beam 30 does not proceed in the direction shown by the dotted line, but its direction of movement is reversed in the electron lens 9 and proceeds in the direction shown by the solid line, passing through the slit 23 and reaching the target 11.

Further, as shown in FIG. 9, the electron beam 31 or electron beam 32 swung in the horizontal direction (second direction) does not travel straight as shown by the dotted line, but the deflection angle is expanded and it advances in the direction shown by the solid line. It passes through the slit 23 and reaches the target 11.

By the way, the horizontal potential distribution in the slit 23 is as shown by equipotential lines 33 in FIG. 10, and has almost no effect on the electron beams 34, 35.

Therefore, the focused electron beams 34, 35 are focused on the target 11.

On the other hand, the vertical potential distribution in the slit 23 is
As shown by equipotential lines 36 in FIG. 1, a convex lens is formed near the slit 23.

For this reason, the focused electron beam once focuses within the electron lens 9 and then tends to diverge when it receives the action of a convex lens near the slit 23 and reaches the target 1.
Focus on 1.

In this case, the convex lens effect strongly acts on the electron beam 37 on the axis, and the electron beam 38 advances toward the slit 23 from above and the slit 23 from below (not shown).
The convex lens effect acts weakly on the electron beam traveling toward .

Therefore, even if the first imaging point 39 is formed in an arcuate shape in the electron lens 9 as shown by the chain line in FIG.
7.38 focuses on target 11.

If there is no convex lens in the slit 23,
The electron beam 37°38 is focused 1 on the dotted line 40 in FIG.
~, the electron beam 38 becomes overfocused, and blurring occurs at the top and bottom of the screen.

Therefore, the slit 23 has an extremely important role in this cathode ray tube, and even if the first imaging point 39 is arcuate, it must be provided at a width and position that can correct this.

Furthermore, the width and position of the slit 230 must be determined in consideration of the reversal position of the electron beam traveling direction within the electron lens 9.

That is, the slit 23 must be provided in such a way that substantially all of the electron beam traveling in reverse can pass therethrough.

In this electron lens 9, the second and fourth surfaces 16, 18 of the first t-pole 12 and the second and fortieth surfaces 20, 22 of the second electrode 13 are the first and third surfaces, respectively. The reason for protruding or curving in the opposite direction is not only to further expand the deflection angle of the electron beam deflected in the horizontal direction, but also to eliminate pattern distortion.

If the ends 26 of the second and fourth surfaces 16 and 18 of the first electrode 12 and the second and fourth surfaces 20 of the second electrode 13,
If the shape of the edges 28 of 22 is not taken into account, the pattern will be bottle-cushioned or arcuate on the left and right sides of the screen.

As is clear from the above, according to this embodiment, the slit 23 is provided on the target side surface of the cylindrical electron lens 9, and the convex lens effect near the slit 23 is utilized.
It becomes possible to focus the electron beam swung in the vertical direction onto the target 11, and a display with less vertical blur becomes possible.

Also, since there is no mesh, the efficiency of the electron gun increases by about 50%.

In addition, the electron beam swung vertically (up and down) is largely inverted within the electron lens 9, and the deflection angle of the electron beam swung left and right is expanded, so the deflection sensitivity can be adjusted to 30~30 in both the vertical and horizontal directions. It is possible to improve this by 40%.

Next, other embodiments and modifications of the present invention will be described.

However, the same parts as in the first embodiment are given the same reference numerals and the explanation thereof will be omitted.

FIG. 12 shows an electronic tzyz 9a according to a second embodiment of the present invention.

In this electronic lens 9a, the box is not fan-shaped from one side to the other, but is formed in a rectangular shape.

In this case, the second and fourth surfaces 16°1 of the first electrode 12
As point 8 moves further away from the electron beam, the radius of curvature of end 26 increases as it approaches a straight line.

With this configuration, although the sensitivity in the horizontal direction is slightly worse than in the first embodiment, it is possible to obtain the same effects as in the first embodiment.

FIG. 13 shows an electronic lens 9 according to a third embodiment of the present invention.
b.

In this embodiment, the lens effect is adjusted by making the fifth surface 24 on the target side protrude toward the target side with a curvature.

Even with this configuration, the same effects as in the first embodiment can be obtained.

FIG. 14 shows an electronic lens 9 according to a fourth embodiment of the present invention.
It also shows c.

In this embodiment, the second electrode 13 is shaped like a trumpet to spread toward the target.

Even if formed in this way, the same effects as in the first embodiment can be obtained.

FIG. 15 shows an electronic lens 9 according to a fifth embodiment of the present invention.
This is the one that shows d.

In this embodiment, the division curve between the first electrode 12 and the second electrode 13 is reversed from that in the first embodiment.

Therefore, in this case, a voltage of, for example, OV is applied to the first electrode 12, and a voltage of, for example, +1300V to +2 is applied to the second electrode 13.
A voltage of 000V (a voltage higher than that of the first electrode 12) is applied.

This embodiment also provides the same effects as the first embodiment.

FIG. 16 shows an electronic lens 9 according to a sixth embodiment of the present invention.
It shows e.

The electron lens 9e is formed to have a flat, substantially elliptical cross section.

Even with this formation, the first electrode 12 substantially has first, second, third and fourth surfaces 15, 16, 17, 18, and the second electrode 13 has first surfaces 15, 16, 17, 18. , second, third, and fourth
Since planes 19°20, 21 and 22 are formed, the respective ends 25, 26, 27 and 28 of the divided portion are formed with a predetermined curvature.

Further, a slit 23 is provided on the fifth surface 24 on the target side.

Even with this configuration, effects similar to those of the first embodiment can be obtained.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments and can be further modified.

For example, as shown in FIG. 17, the electron lens 9 according to the present invention may be provided in a cathode ray tube having three sets of quadrupole lenses 51.degree. 52.53 as focusing lenses without providing a mesh.

The system shown in FIG. 17 uses a quadrupole lens 53 to strengthen the deflection expansion in the vertical direction, and also focuses the beam at the same focusing angle in the upper, lower, left, and right directions.

In this case, with the beam traveling direction of the lens 51 as a reference, the upper and lower electrodes are set at, for example, 0 to -400V, the left and right electrodes of the lens 51 are set at +400V, the upper and lower electrodes of the lens 52 are set at +400V, and the left and right electrodes of the lens 52 are set at +400V, for example. For example, O to -4oov, -ioo to -300V, for example, is applied to the upper and lower electrodes of the lens 53, and, for example, OV is applied to the left and right electrodes of the lens 53.

Even in this case, the same effects as in the first embodiment can be obtained.

Further, as shown in FIG. 18, the structure is such that a quadrupole lens 61 is added to the cathode ray tube of the first embodiment, and the upper and lower electrodes are set at, for example, -100 to -300 V with respect to the electron beam traveling direction.
For example, OV may be applied to the left and right electrodes.

Even with this configuration, the same effects as in the first embodiment can be obtained.

Further, the fifth surface 24 may not be flat but may be spherical.

It is also possible to change the curved direction of the ends 25, 26, 27, 28 in FIGS. 12, 13, 14, and 16 to the same direction as in FIG. 15.

Furthermore, although an electrostatic focusing electron gun is shown in the embodiments and modifications, this may be an electromagnetic focusing electron gun.

Furthermore, although the deflection systems in the embodiments and modified examples have an electrostatic deflection structure, they may also have an electromagnetic deflection structure.

In addition, in the embodiment, the present invention is applied to a cathode ray tube for an oscilloscope, but there are various types of cathode ray tubes that have an electrode at a stage downstream of the deflection system that can produce a convex lens effect in the slit 23, similar to the rear acceleration electrode 10. Of course, it is also applicable to pipes (for example storage pipes).

[Brief explanation of the drawing]

1 to 11 show a cathode ray tube according to a first embodiment of the present invention, FIG. 1 is a schematic sectional view of the cathode ray tube, and FIG. 2 is a perspective view illustrating an electron lens. Figure, No. 37
is a plan view of the electron lens, Figure 4 is a side view of the electron lens,
Figure 5 is a left side view of the first electrode, Figure 6 is a right side view of the second electrode, Figure 7 is a cross-sectional view of the FIG. 9 is a beam trajectory diagram that explains the action of the electron lens when the electron beam is swung in the horizontal direction, and FIG. FIG. 11 is a beam trajectory diagram showing the relationship between the horizontal direction change of the beam and the spot, and FIG. 11 is a beam trajectory diagram showing the relationship between the vertical direction change of the beam and the spot. Figures 121, 13, 14, 15, and 1
FIG. 6 is a perspective view illustrating electronic lenses according to second, third, fourth, fifth, and sixth embodiments. FIG. 17 is a sectional view showing a modified example of the cathode ray tube, and FIG. 18 is a sectional view showing another modified example of the cathode ray tube. In the symbols used in the drawings, T is a vertical deflection plate, 8 is a horizontal deflection plate, 9 is an electron lens, 10 is a rear acceleration electrode, 11 is a target, 12 is a first electrode, and 13 is a second electrode.
, 23 is a slit, and 24 is a fifth surface.

Claims (1)

[Claims] 1. An electron gun, a deflection system that deflects an electron beam emitted from the electron gun in a first direction and a second direction perpendicular to the first direction, and from the deflection system. at least one rear-stage electrode provided at a rear stage; a substantially flat cylindrical electron lens disposed near the rear-stage electrode; and a target for impacting the electron beam emitted from the electron gun. and the electron lens is configured to include at least a cylindrical lens having substantially first, second, third, and fourth surfaces and through which the electron beam can pass. 1 electrode, a cylindrical part having substantially first, second, third, and fourth surfaces, and a slit having a width that allows the electron beam to pass through the target-side opening of the cylindrical part. a second electrode disposed adjacent to said first electrode having a fifth surface substantially occluded by said first electrode; The target side end of the third surface opposite to the first surface has a curvature and is formed in a concave or convex shape, and the third surface of the second electrode and the first
The electron gun side end of the third surface opposite to the surface of is formed in a concave or convex shape with curvature, and the traveling direction of the electron beam swung in the first direction by the deflection system is A cathode ray tube, characterized in that the electron beam is configured to be inverted within a lens and configured to cause the slit to have a lens action that focuses the electron beam in the first direction. 2 the second and fourth surfaces of the first electrode are
and a target-side end of the fourth surface is curved in a direction opposite to the curve direction of the target-side ends of the first and third surfaces of the first electrode, and Second
and a fourth surface, wherein the electron gun side ends of the second and fourth surfaces are in a direction opposite to the curve direction of the electron gun side ends of the first and third surfaces of the second electrode. The cathode ray tube according to claim 1, which is curved. 3. The cathode ray tube according to claim 1 or 2, wherein the cylindrical electron lens is formed in a fan-shaped box shape. 4. The cathode ray tube according to claim 1 or 2, wherein the cylindrical electron lens is formed in a flat box shape. 5. The cathode ray tube according to claim 1 or 2, wherein the cylindrical electron lens is formed to have a flat, substantially elliptical cross section.