JP2000182535A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode-ray tube equipped with a high-resolution and low-cost electron gun. SOLUTION: Tubular projection parts 238 corresponding to respective cathodes are provided on a single plate-like body 237, and an electron-beam passing hole 233 is formed in a top part of each projection part 238 while a curved wall part 239 where the inner diameter of the projection part 238 is gradually reduced toward the top part is formed on a base part of each projection part 238. It is easy to cause a difference in the bore of an electron-beam passing hole between both surfaces of a plate-like electrode made up of a single plate body, the electrode length can be enlarged, the change of an electric field in the electron-beam passing hole is made gradual, astigmatism is thereby reduced, and the range of optimum design is expanded and therefore focusing characteristics can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly, to a color cathode ray tube having an in-line type electron gun for emitting a plurality of electron beams in parallel on a horizontal plane.

[0002]

2. Description of the Related Art A color cathode ray tube such as a color picture tube or a display tube is widely used as a television broadcast receiver or a monitor of various information processing devices because of its fine image reproducibility.

This type of color cathode ray tube emits an electron beam toward the phosphor screen at a panel portion having a phosphor screen formed on the inner surface, a funnel portion connected to the panel portion, and an end of the funnel portion. It consists of a vacuum envelope consisting of a neck that houses the electron gun structure. And
As the above-mentioned electron gun, those provided with an in-line type electron gun which emits a plurality of electron beams in parallel on one horizontal plane are widely used.

FIG. 8 is a side view of an essential part for explaining an example of the configuration of an in-line type electron gun used in this type of color cathode ray tube, and shows a side view seen from a direction parallel to the in-line arrangement direction of electron beams. .

In FIG. 8, reference numeral 20 denotes a cathode, reference numeral 21 denotes a first electrode which is a control electrode, and reference numeral 22 denotes a second electrode which is an acceleration electrode.
Constitutes an electron beam generator.

Also, reference numerals 23 and 24 denote third electrodes made of plate electrodes.
The electrode and the fourth electrode, 25 and 26 are the fifth and sixth electrodes formed of cylindrical electrodes, and 27 is the anode, and these electrodes constitute an acceleration focusing unit. 28 is a shield cup, 2
Reference numeral 9 denotes an insulating support (multi-form glass) for fixing the electrodes in a predetermined order and at intervals.

[0007] The three electron beams generated by the electron beam generating section composed of the cathode 20 and the three-electrode section composed of the first electrode 21 and the second electrode 22 are applied to the third electrode 23 and the fourth electrode 23.
The required focusing is performed by the main lens formed on the facing surface of the sixth electrode 26 and the anode 27 after being accelerated and focused at the electrode 24 and the fifth electrode 25 and directed toward the phosphor screen.

In this type of electron gun, the first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 are plate-shaped electrodes, and form an electrode (fifth electrode) that forms a focusing lens and a main lens. 25, the sixth electrode 26, and the anode 27) are constituted by cup-shaped electrodes.

In the third electrode 23, the diameter of the electron beam passage hole on the second electrode 22 side is smaller than the diameter of the electron beam passage hole on the fourth electrode 24 side.

FIG. 9 is an explanatory view of the third electrode in FIG. 8, wherein (a) is a plan view seen from the second electrode side, and (b) is a side view showing a partial cross section of (a).

The third electrode 23 is composed of two electrode parts. That is, the first component 231 formed into a cup shape having the small-diameter electron beam passage hole 233 and the plate-shaped second component 232 having the electron beam passage hole larger than the electron beam passage hole 233 are bonded. , Welded and integrated. In addition, 235 is a tab to be embedded in the multi-form glass.

FIG. 10 is a sectional view taken along the line AA in FIG. The first component 231 has 3 on the second grid electrode side.
The second component 232 is a plate-shaped component having three electron beam passage holes 234 having a diameter larger than the diameter of the electron beam passage hole 233.

[0013] These two parts are bonded and welded,
An integrated third electrode 23 is formed. First part 231
The diameter d of the electron beam passage hole 233 on the second electrode side formed on the second component 232 is smaller than the diameter D of the electron beam passage hole 234 on the fourth electrode side formed on the second component 232 (D> d).

FIG. 11 is a schematic process diagram illustrating a conventional method for manufacturing an electrode using two components. That is, the first
Three electron beam passage holes are formed on the convex part of the plate of the component by pressing. This is subjected to a deburring process of the electron beam passing hole by barrel processing. Similarly, the plate body of the second part also forms three electron beam passage holes by pressing.
Deburring of the electron beam passage hole is performed by barrel processing.

[0015] Then, the centers of the electron beam passage holes of the first component and the second component are aligned and bonded, and then integrated by welding.

Incidentally, there is also a type in which three protruding portions are formed by pressing such an electrode on a single plate.

[0017]

However, the electron gun used in the above-mentioned conventional color cathode ray tube has a third grid electrode composed of two electrode parts. There is a limit to the positional accuracy of the beam passage hole, the parallelism of the electrodes is reduced, the focus characteristic is degraded, the number of press steps and barrel steps is large, and the production cost is large.

Further, the use of a single plate is excellent in manufacturing cost, but since it is a single plate,
Since the electrode length cannot be increased, the range of the optimal design of the electron gun is limited. Further, in the case of using a single plate, there is a problem that the diameters of the electron beam passage holes on the adjacent electrodes (the second electrode side and the fourth electrode side) cannot be made different.

Further, in the case of using a conventional single plate, there is a problem that astigmatism occurs and the resolution is reduced because the base of the overhanging portion has a shape that rises rapidly.

That is, FIG. 12 is a schematic diagram for explaining the occurrence of astigmatism in a conventional plate-like electrode having a projecting portion formed using a single plate. Cylindrical overhang 238
A part of the electric field Ef formed between the plate-like electrode 23 having the above-described pattern and the adjacent electrode 24 penetrates into the overhang portion 238. Since the base of the overhang portion 238 rises sharply, the intrusion electric field Eff changes greatly. Therefore, the spherical aberration increases, the beam spot on the phosphor screen increases, and the resolution deteriorates.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a color cathode ray tube having a high-resolution and low-cost electron gun.

[0022]

In order to achieve the above-mentioned object, the present invention provides a single plate-like body provided with a cylindrical overhang corresponding to each of the cathodes, and an electron on the top of the overhang. In addition to forming the beam passage hole, a curved wall portion was formed at the base of the overhang portion, in which the inner diameter of the overhang portion gradually changed to a smaller diameter toward the top.

A typical configuration of the present invention is described as follows. That is, (1) a vacuum envelope composed of a panel part on which a phosphor screen is formed, a neck part accommodating an electron gun, and a funnel part connecting the panel part and the neck part; A color cathode-ray tube including a deflection yoke, wherein the electron gun includes an electron beam generating unit including a plurality of cathodes that emit a plurality of electron beams arranged on a horizontal plane, an acceleration electrode, and a control electrode; A plurality of electrodes including at least one plate-shaped electrode having a plurality of electron beam passage holes corresponding to the plurality of electron beams, a plurality of electrodes including a plurality of cup-shaped electrodes, and a focusing accelerator configured by an anode; The electrode has a cylindrical overhang protruding toward the adjacent electrode corresponding to the plurality of electron beams formed by press molding on a single plate, and the top of the cylindrical overhang is provided. An electron beam passage hole was formed in the portion, and a curved wall portion in which the inner diameter of the overhang portion gradually decreased toward the top portion was formed at the cylindrical base of the overhang portion.

With this configuration, there is no abrupt change in the penetration of the electric field formed between the adjacent electrodes into the inside of the overhanging portion, so that the spherical aberration is small and the beam on the phosphor screen is small. The increase in spots is suppressed, and the resolution is improved.

(2) The ratio (H / D) of the overhang height H of the overhang portion to the inner diameter D of the overhang portion in (1) is in the range of 0.3 to 1.0.

The cylindrical projection is not limited to a completely cylindrical shape. For example, the projection may have a substantially trapezoidal cross section, and the base may have a curved wall with a diameter gradually decreasing toward the top. As a result, the same effect as in the above (1), that is, the penetration of the electric field formed between the adjacent electrodes into the overhang portion transitions gently (in other words, the electric field penetrates into the overhang portion). (The electric field does not change abruptly).

According to the configuration of the present invention, the displacement of the electron beam passage holes formed on both sides of the plate electrode can be reduced, and the diameters of the electron beam passage holes on both sides can be arbitrarily set. As a result, it is possible to obtain a high-resolution image by suppressing astigmatism, to reduce the number of parts and the number of manufacturing steps, and to provide a high-quality color cathode ray tube at low cost.

[0028]

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

FIG. 1 is an explanatory view of a first embodiment of a third electrode of an electron gun applied to a color cathode ray tube according to the present invention.
(A) is a plan view seen from the second electrode side, and (b) is a side view showing a partial cross section.

The third electrode 23 is connected to a single plate
Three cylindrical projections 238 corresponding to the respective cathodes are formed by press-forming so as to protrude toward the second electrode, and three electron beam passage holes 233 are formed at the tops (bottom surfaces of the projections 238). Perforated.

FIG. 2 is a sectional view taken along the line AA of FIG. The diameter of the electron beam passage hole 233 pierced at the top of the overhang portion 238 at the pitch S is d, and the base of the overhang portion 238, that is, the electron beam passage hole 2 on the fourth electrode side is formed.
The aperture of D is D, and has a relation of D ≧ d. Also,
The height of the overhang is H.

These electron beam passage holes 233 and 2
34, it is easy to arbitrarily set the dimensions D, d, and H under the relationship of D ≧ d. Therefore, the latitude for optimal design of the electron gun is increased.

Further, at the base of the overhang portion 238, a curved wall portion is formed on the inner wall (the edge of the electron beam passage hole 234 facing the adjacent electrode), the inner diameter of which is gradually reduced. The curved wall portion is formed by forming a curved wall portion 239 having a curvature at the inner wall edge of the base of the overhang portion 238.

The diameter of the electron beam passage hole 234 at the base of the overhang portion 238 is set to D and the height of the overhang is adjusted by setting the ratio (H / D) of H to 0.3 to 1.0. The amount of change in the electric field formed inside the portion 238 can be suppressed to suppress astigmatism. This ratio (H / D)
The reason for setting the value in the range of 0.3 to 1.0 is that the electrode was actually manufactured, an electron gun was assembled, and the operation of a color cathode ray tube assembled using the electron gun was verified. It is.

By forming such a curved wall portion 239, the diameter of the base of the overhang portion (the opening diameter of the electron beam passage hole) is increased, and the overhang portion of the electric field formed between the adjacent electrode is formed. The change of the electric field component entering the inside of the device becomes gentle.

Therefore, astigmatism in the electron lens formed by the electron beam passage hole 233 formed at the top of the overhang portion 238 and the electron beam passage hole 234 at the base is reduced. As a result, it is possible to obtain a color cathode ray tube capable of displaying a high-resolution image.

FIG. 3 is a schematic process diagram for explaining a method of manufacturing a plate-shaped electrode according to this embodiment. That is, after a single plate body is press-formed to form a cylindrical overhang having an electron beam passage hole at the top, a barrel process is performed.

FIG. 4 is an explanatory view of a method of forming an electron beam passage hole at the top of the overhang. The formation of the electron beam passage hole 233 may be performed at the same time as the pressing of the overhanging portion, or may be performed by a punch press after the pressing of the overhanging portion.

The holes for the electron beam passing holes 233 may be formed in the direction indicated by the arrow A from the outside of the projecting portion as shown in FIG. 4A, or may be formed in the direction indicated by the arrow B from the inside of the projecting portion as shown in FIG. The direction shown in FIG.

After forming the electron beam passage holes 233, burrs generated in the electron beam passage holes 233 in the barrel process are removed. Because of the ease of removing burrs in this barrel process, the electron beam passage holes 233 are set in the direction shown in FIG.
Is preferably formed.

FIG. 5 is an explanatory view of various examples of planar shapes and arrangements of electron beam passage holes formed at the top of the overhang portion.
FIG. 3A shows three electron beam passage holes 233a (side beam passage holes), 233b (center beam passage holes),
233c (side beam passage holes) are both circular at a pitch S.

FIG. 4B shows an ellipse in which, out of the three electron beam passage holes 233a, 233b, and 233c, the centers of the side electron beam passage holes 233a and 233c are offset at a pitch S 'outward in the inline direction. FIG. 3 (c) shows three electron beam passing holes 233a, 2c.
33b and 233c, the side electron beam passage holes 2
An ellipse in which the centers of 33a and 233c are offset inward in the inline direction by a pitch S ″ is shown.

The three electron beam passage holes 233a, 233
b and 233c may be any of the above (a), (b) and (c), but in this embodiment, the shape of (a) is adopted.

FIG. 6 is a sectional view similar to FIG. 2 illustrating a second embodiment of the third electrode of the electron gun applied to the color cathode ray tube according to the present invention. In this embodiment, the cylindrical projection 238 has a substantially trapezoidal cross section, and the opening (electron beam passage hole) 234 on the large diameter side of the projection 238.
Becomes gradually smaller in the direction of the opening (electron beam passage hole) 233 formed at the top of the overhang portion 238,
The change of the electric field penetrating from the adjacent electrode side becomes gentle, and astigmatism can be reduced.

A curved wall similar to that shown in FIG. 2 can also be formed on the inner wall edge of the electron beam passage hole 234. The dimensional relationships of the overhangs in this embodiment are the same as in the previous embodiment.

According to this embodiment, a color cathode ray tube capable of displaying a high-resolution image can be obtained.

FIG. 7 is a sectional view taken along the tube axis for explaining the overall structure of the color cathode ray tube according to the present invention. 1 is a panel portion, 1a is a screen, 2 is a neck portion, 3 is a funnel portion, 4 is a phosphor screen, 5 is a shadow mask, 6 is a mask frame, 7 is a magnetic shield, 8 is a shadow mask suspension mechanism, and 9 is an in-line type. Electron gun, 10 is a deflection yoke, 11
Is an inner conductive layer, 12 is an outer conductive layer, 13 is a contact spring for supplying an anode voltage to the electron gun, 14 is a getter, 15 is a stem for supplying a video signal and other various voltages to the electron gun, 16 Is an anode terminal, and 17 is a tension band.

In this color cathode ray tube, a vacuum envelope is formed by a panel portion 1 and a neck portion 2 and a funnel portion 3 connecting the panel portion 1 and the neck portion 2.
The connection between the and the funnel 3 is tightened by a tension band 17.

On the inner surface of the panel section 1, a phosphor screen 4 is formed by applying phosphors of three colors of red, green and blue in a stripe or dot form to form a phosphor screen.

The in-line type electron gun housed inside the neck 2 emits three electron beams in-line. Further, a shadow mask 5 which is a color selection electrode having a large number of apertures or an interdigital grid is provided near the fluorescent screen 4 inside the panel section 1. B indicates three electron beams, and a deflection yoke 10 is provided in a transition region between the funnel 3 and the neck 2.

The electron gun 9 is the same as that shown in FIG. 1, FIG.
Having a plate-like electrode having the structure described in the above, anode voltage is supplied by a contact spring 13 from an anode terminal 16 formed in the funnel portion 3 via the internal conductive layer 11, and three electrodes are fired in-line from the electron gun 9. The electron beam B is deflected in two directions, horizontal and vertical, by a vertical deflection magnetic field and a horizontal deflection magnetic field generated by a deflection yoke 10, and is subjected to color selection by a shadow mask 5 to be applied to respective phosphors forming a phosphor screen 4. By colliding, a color image is formed on the screen 1a.

According to this color cathode ray tube, better focus can be obtained as compared with the conventional color cathode ray tube, and a high-resolution color image can be displayed.

The present invention makes it possible to make the diameters of the electron beam passage holes on both sides different by projecting and forming the third electrode, which is a plate-like electrode constituting the electron gun, on a single plate. , The astigmatism is reduced, and the electrode length is substantially increased. However, the present invention is not limited to this, and can be applied to other plate-like electrodes requiring the same function. It is needless to say that the present invention is not limited to the electron gun of the color cathode ray tube.

[0054]

As described above, according to the present invention,
It is easy to make the diameters of the electron beam passage holes on both sides of a plate-like electrode composed of a single plate body easy, and it is possible to increase the electrode length, and to change the electric field in each electron beam passage hole. Can be reduced to reduce astigmatism, and the focus characteristic can be improved by expanding the range of optimal design.

Further, it is possible to obtain a grid electrode having a required electrode length with a single component, and it is possible to reduce the manufacturing cost of a color cathode ray tube.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a first embodiment of a third electrode of an electron gun applied to a color cathode ray tube according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a schematic process diagram illustrating a method for manufacturing a plate-shaped electrode according to a first embodiment of the present invention.

FIG. 4 is an explanatory view of a method for forming an electron beam passage hole at the top of the overhang.

FIG. 5 is an explanatory diagram of various examples of planar shapes and arrangements of electron beam passage holes formed at the top of the overhang portion.

FIG. 6 is a sectional view similar to FIG. 2, illustrating a second embodiment of the third electrode of the electron gun applied to the color cathode ray tube according to the present invention.

FIG. 7 is a cross-sectional view along the tube axis for explaining the overall configuration of the color cathode ray tube according to the present invention.

FIG. 8 is a main part side view for explaining a configuration example of an in-line type electron gun used for a color cathode ray tube.

9 is an explanatory diagram of a third electrode in FIG.

FIG. 10 is a sectional view taken along line AA of FIG. 9 (a).

FIG. 11 is a schematic process diagram illustrating a conventional method for manufacturing an electrode using two components.

FIG. 12 is a schematic diagram illustrating the occurrence of astigmatism in a conventional plate-like electrode having a projecting portion formed using a single plate.

[Explanation of symbols]

 23 Third electrode 233 Electron beam passage hole on second electrode side 234 Electron beam passage hole on fourth electrode side 235 Tab 237 Single plate 238 Overhang. 239 Curved wall.

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[Procedure amendment]

[Submission date] December 7, 1999 (1999.12.
7)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Fig. 8

[Correction method] Change

[Correction contents]

FIG. 8

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Tsutomu Tojo 3300 Hayano Mobara-shi, Chiba Pref.Electronic Devices Division, Hitachi, Ltd. (72) Inventor Masahiro Ito 3350 Hayano Mobara-shi Chiba Pref In-house F-term (reference) 5C041 AA03 AA14 AB07 AC02 AC04 AC26 AD02 AE01

Claims (2)

[Claims] 1. A panel part on which a phosphor screen is formed,
A color cathode ray tube comprising: a vacuum housing composed of a neck portion accommodating an electron gun, a funnel portion connecting the panel portion and the neck portion, and a deflection yoke provided on the funnel portion. The gun has an electron beam generating unit including a plurality of cathodes for emitting a plurality of electron beams arranged on one horizontal plane, an acceleration electrode and a control electrode, and a plurality of electron beam passage holes corresponding to the plurality of electron beams. At least one having
A plurality of electrodes including a plurality of plate-shaped electrodes and a plurality of cup-shaped electrodes, and a focusing accelerator configured by an anode, wherein the plate-shaped electrodes are formed into a single plate by press molding to the plurality of electron beams. Correspondingly, it has a cylindrical overhang protruding on the adjacent electrode side and an electron beam passage hole is formed at the top of the cylindrical overhang, and the cylindrical base of the overhang is directed toward the top. A color cathode ray tube, wherein a curved wall portion in which the inner diameter of the overhang portion gradually changes to a smaller diameter is formed. 2. The collar according to claim 1, wherein the ratio (H / D) of the overhang height H of the overhang portion to the inner diameter D of the overhang portion is in the range of 0.3 to 1.0. Cathode ray tube.