JPH11260293A - Cathode ray tube - Google Patents

Abstract

(57) [PROBLEMS] To maintain the symmetry of a raster formed by an electron beam emitted from each electron gun in a cathode ray tube in which a phosphor screen is dividedly scanned by a plurality of electron guns,
It was difficult to smoothly connect the rasters without any seams. SOLUTION: In a cathode ray tube which divides and displays a screen in a plurality of regions in a longitudinal direction thereof, an inner surface of a glass panel 14 on which a phosphor screen is formed is formed so that a radius of curvature in a longitudinal direction is substantially infinite, By forming a substantially cylindrical curved surface having a constant curvature in the short axis direction, central axes (normal axes) passing through the centers of the respective divided regions become parallel to each other, and the electron gun and the neck 17 arranged on the normal axes Are also parallel to each other.
Accordingly, the raster of each divided area is symmetrical in up, down, left, and right directions, and connection of two screens is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a vacuum envelope of a cathode ray tube for scanning a phosphor screen by dividing a phosphor screen by a plurality of electron guns, and more particularly to the inner surface shape of a glass panel and the arrangement position of a neck.

[0002]

2. Description of the Related Art In recent years, various studies have been made to meet demands for high-definition picture tubes for high-definition broadcasting or accompanying large screens. In order to achieve higher resolution of the picture tube, the electron beam spot diameter on the screen surface must be reduced.

On the other hand, the electrode structure of an electron gun, which is an electron beam generating source, has been conventionally improved, or the diameter and length of the electron gun itself have been increased. However, sufficient results have been obtained. Absent. This is mainly because the distance from the electron gun to the phosphor screen becomes longer as the tube becomes larger, and the magnification of the electron lens becomes too large. Therefore, it is important to shorten the distance from the electron gun to the phosphor screen in order to realize high resolution. In this case, if wide-angle deflection is used,
This leads to an increase in the magnification difference between the center and the periphery of the screen. For this reason, wide-angle deflection is not advantageous for achieving high resolution.

[0004] For this reason, a method of arranging a plurality of independent small picture tubes to provide a large screen with high resolution has been disclosed in the prior art.
JP-A-48-90428, JP-A-49-21019, and JP-A-53-117
No. 130 and the like. This type of method is effective for displaying a huge screen with a large number of divisions placed outdoors, etc., but when displaying a medium-sized large screen with a screen size of about 40 inches, joining the screens between the areas The part stands out and reproduces an unsightly image. Therefore, when used as a home television receiver or when used as a terminal for graphic display in computer-aided design (CAD), the connection portion of the screen becomes a fatal defect.

On the other hand, US Pat. No. 3,071,706, Japanese Utility Model Publication No. 39-25641, Japanese Patent Publication No. 42-4928,
JP-A-50-17167 and U.S. Pat. No. 4,777,407 disclose a structure in which a plurality of independent phosphor screens of a picture tube are integrated. The picture tube having the phosphor screen of the integrated structure has a vacuum envelope composed of a face plate on which the phosphor screen is formed, a rear plate facing the face plate, and a plurality of funnels adjacent to the rear plate. Have been. The face plate is made of glass, and the rear plate is made of glass or metal. In particular, as for a rear plate made of metal, a plate provided with a reinforcing plate on a relatively thin metal plate is known in order to maintain sufficient strength against atmospheric pressure and to reduce the weight.

However, in such a structure, when the screen surface becomes large, the thickness of the face plate and the rear plate must be increased to withstand the atmospheric pressure load, and the screen surface becomes large in the tube axis direction. It is also necessary to have a curvature. As a result, the weight of the vacuum envelope increases.
Further, when the curvature of the face plate becomes large, the screen becomes difficult to see.

[0007]

As described above, a cathode ray tube having a short depth and an easy-to-see screen is a glass panel having a phosphor screen formed on an inner surface thereof and a funnel having a neck having an electron gun therein. There is a cathode ray tube which includes a deflection device provided in a funnel and scans the phosphor screen by dividing the phosphor screen into a plurality of regions by an electron beam emitted from the electron gun. In this cathode ray tube, images drawn in each area divided and scanned by an electron beam are connected by a signal applied to an electron gun or a deflecting device attached to a funnel corresponding to each electron gun, and a fluorescent screen is used. It reproduces images without breaks or duplication in the whole area.

However, in the cathode ray tube which scans the phosphor screen by dividing the phosphor screen into a plurality of regions by the electron beams emitted from the plurality of electron guns as described above, the raster of each region is cut or overlapped between adjacent regions. It is desirable that the smooth and continuous connection be made without any gaps, in which the size of the raster in each region is the same and has the symmetry of up, down, left and right. Therefore, it is desirable to arrange the electron guns so that the inner surface of the glass panel on which the phosphor screen is formed is as flat as possible and the center axis of the neck inside each electron gun passes through the center of each divided region.

On the other hand, when a glass panel having a flat inner surface is used, particularly in a large cathode ray tube, the glass panel must be made thick to obtain sufficient strength against an atmospheric pressure load applied to the glass panel. Increase is inevitable. Therefore, in a general cathode ray tube, a method of forming a glass panel into a substantially spherical shape projecting outward is widely used. An example using a spherical glass panel is disclosed in Japanese Patent Publication No. 54-12035.

FIG. 4 is a diagram for explaining this method.
Is a tube axis, 2 is a face plate, 3 is an electron gun, 4 is a deflection coil, 5 is a deflection center of the deflection coil 4, O is a center of curvature of the face plate 2, R is a display surface of the face plate 2 and a deflection center O. O ′ indicates the raster center. As shown in FIG. 4, this method is configured such that the deflection center 5 of the electron beam emitted from the electron gun 3 is located on a line connecting the center of curvature O of the face plate and the raster center O 'by the electron beam. It is. FIG.
In the example of (a), the symmetry of the raster is ensured, but the mounting of the deflection coil 4 and the adjustment of the deflection coil 4 are troublesome because the neck is inclined. On the other hand, in the example of FIG. 4B, the necks are parallel to each other, but the strength of the magnetic field generated by the deflecting coil 4 (the current flowing through the deflecting coil) is made asymmetric or the coils are arranged so that the deflecting magnetic field becomes asymmetric. A measure such as designing is required, and the design, manufacture, adjustment, and drive circuit of the deflection coil 4 become complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is formed by an electron beam emitted from each electron gun in a cathode ray tube in which a phosphor screen is dividedly scanned by a plurality of electron guns. An object of the present invention is to maintain the symmetry of the raster, eliminate the seam of each raster, smoothly connect the rasters, and further simplify the design, manufacture, mounting, adjustment, and configuration of the drive circuit of the deflection coil.

[0012]

A glass panel in which a phosphor screen formed on an inner surface is horizontally long and has a substantially rectangular shape;
A vacuum valve comprising a funnel having a plurality of necks with an electron gun therein, and a deflecting device provided on the funnel, wherein the phosphor screen is divided into a plurality of regions by an electron beam emitted from the electron gun. In the cathode ray tube for scanning, the glass panel has an almost infinite radius of curvature in the major axis direction of the phosphor screen and a substantially cylindrical curved surface having a constant curvature in the minor axis direction, and the neck is in the major axis direction. And arranged parallel to each other.

Further, the glass panel has an almost infinite radius of curvature from the center to the vicinity of the short side in the major axis direction of the phosphor screen, has a constant radius of curvature near the short side, and has a constant radius in the short axis direction. The necks are arranged in the major axis direction and are parallel to each other.

As described above, in a cathode ray tube for displaying a screen divided into a plurality of regions in the major axis direction, the inner surface of the glass panel on which the phosphor screen is formed is formed so that the radius of curvature in the major axis direction is almost infinite. By making it substantially large and making it a substantially cylindrical curved surface having a constant curvature in the short axis direction, the central axes (normal axes) passing through the centers of the respective divided regions become parallel to each other, and the electron gun arranged on this normal axis And the neck are also parallel to each other. Accordingly, the raster of each divided area is symmetrical in up, down, left, and right directions, and connection of two screens is simplified.

Raster symmetry is important for simplifying the connection of two screens. Needless to say, the ideal phosphor screen shape is a flat surface having no curvature in both the short and long axes. Glass panels with flat phosphor screens are generally difficult to obtain sufficient strength against atmospheric pressure loads, especially in large cathode ray tubes,
It is unavoidable to increase the thickness and weight of the glass. In general, the glass panel of a large cathode ray tube has a substantially spherical shape protruding outward or a substantially cylindrical curved surface having a curvature only in the long axis direction in consideration of the above problem, and has a sufficient strength against atmospheric pressure load. Is added.

In the cathode ray tube which scans the phosphor screen by dividing the phosphor screen into a plurality of regions as in the present invention, it is necessary to balance the symmetry of each raster and the strength of the glass panel. A cylindrical curved surface having curvature only in the direction was used. As described above, in the present invention, since the necks in which the electron guns are provided can be made parallel to each other, the design, manufacture, mounting, adjustment, and drive circuit of the deflection device can be simplified.

Further, the radius of curvature from the center to the vicinity of the short side in the major axis direction is substantially infinite, the radius of curvature is constant in the vicinity of the short side, and the curvature is substantially cylindrical in the minor axis direction. In order to improve the strength of the glass panel against atmospheric pressure load, to secure the symmetry of the raster at the joint of the divided screens, to easily and smoothly connect the divided images, and to arrange the necks in parallel with each other By doing so, the mounting and adjustment of the deflecting device and the like can be simplified.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments with reference to the drawings. FIG. 1 shows a front view and a side view (including a partial cross section) of a cathode ray tube according to the first embodiment. The cathode ray tube 11 has a glass plate 14 including a substantially rectangular face plate 12 having a major axis and a minor axis, and a side wall 13 extending substantially perpendicularly from a peripheral portion of the face plate 12. Funnel 1 connected to the glass panel 14 and having two funnel-shaped cones 15
6 and a vacuum valve 18 comprising a neck 17 connected to the funnel 16. A phosphor screen is formed on the inner surface of the glass panel. An electron beam emitted from an electron gun (not shown) inside the neck is deflected and scanned by a deflector (not shown) provided on a funnel. Then, an image (or raster) is formed on the phosphor screen. In this embodiment, the phosphor screen (2
(Dotted line) is divided into two in the major axis direction, divided into two divided regions, and the electron gun and the neck are arranged on a normal axis passing through the center of each divided region. Each raster formed by the electron beam emitted from each electron gun is equal in size to each divided region, and the rasters are connected smoothly and seamlessly on the phosphor screen to form one large raster. The glass panel of the present invention is a substantially cylindrical curved surface having a substantially infinite radius of curvature in the major axis direction and a constant radius of curvature in the minor axis direction. In this embodiment, the radius of curvature in the major axis direction is about 100000 mm, which is close to an infinite radius of curvature. The radius of curvature in the minor axis direction is about 2000 mm. In this embodiment, the necks are arranged on a normal axis passing through the center of each divided area, and both necks are arranged substantially in parallel, so that mounting and adjustment of the deflecting device can be simplified.

FIG. 2 shows a second embodiment of the present invention, which is an example in which the image is divided into three parts in the major axis direction. Also in this embodiment, the inner surface of the glass panel 14 is a substantially cylindrical curved surface having a substantially infinite radius of curvature in the major axis direction and a constant radius of curvature in the minor axis direction. Similarly to the above, the radius of curvature in the major axis direction is about 100000 mm, which is close to an infinite radius of curvature. The radius of curvature in the short axis direction is about 2000m
m. The necks 17 are arranged on a normal axis passing through the center of each divided region, and the three necks 17 are parallel to each other. Therefore, as in the case of the first embodiment, the neck 17
Are arranged substantially in parallel, so that mounting and adjustment of the deflection device can be simplified.

FIG. 3 shows a third embodiment of the present invention.
Also, the inner surface shape is different from the glass panel 14 of the second embodiment. In this embodiment, the radius of curvature from the center to the vicinity of the short side in the major axis direction is almost infinite, the radius of curvature is near the short side, the radius of curvature is constant, and the minor axis direction is a substantially cylindrical curved surface having a constant curvature. I have. Specifically, in the effective area where the phosphor screen is applied on the inner surface of the panel and an image is displayed, the radius of curvature in the major axis direction is about 100000 mm in an area of about 85% from the center to the vicinity of the short side, and the radius of curvature is Can be approximated to almost infinity, about 15% near the short side
Average radius of curvature in the long axis direction is about 500 m
m. In this embodiment, the strength of the glass panel 14 with respect to the atmospheric pressure load can be improved by reducing the radius of curvature near the short side. In the present invention,
The symmetry of the raster displayed in each of the divided areas is ensured, and the connection of the divided images is easily and smoothly performed. The necks 17 are arranged in parallel to simplify the mounting and adjustment of the deflection device. Is what you do. In this embodiment, it is obvious that the left-right symmetry of the raster is deteriorated, but the effect is only a part of the vicinity of the short side, and the symmetry is lost, but the influence on the whole is small, and at the seam of the image. There is no effect on the vicinity of a certain center. In addition, neck 1
7 does not incline, so that there is no deterioration in the mountability and workability of the deflecting device. Rather, the effect of reducing the radius of curvature near the short side and improving the strength of the glass panel is great. In some cases, the industrial value is higher than that of the second embodiment. However, in this embodiment, attention must be paid to the appearance of the phosphor screen near the short side. That is, if the area having a small radius of curvature in the major axis direction is set wide, the phosphor screen looks rounded, and the effect is particularly remarkable when viewed obliquely. The inventors examined the appearance of the peripheral portion of the phosphor screen using various models. As a result, depending on the curvature near the short side, the radius of curvature in the region exceeding approximately 20% of the phosphor screen in the major axis direction was found. We found that it was easier to feel roundness when it was made smaller. Further, when this region is approximately 5% or less, although there is no roundness, the effect of improving the atmospheric pressure intensity is small. In the present embodiment, the region having a small radius of curvature is set to 15% based on the above-described study result, with priority given to inconspicuous roundness. Of course, the present invention does not specify the size of the radius of curvature or the width of the region having a small radius of curvature, and considers the appearance of the peripheral portion of the phosphor screen (especially near the short side) and the atmospheric pressure intensity of the glass panel as described above. Can be set as appropriate.

In this embodiment, the case where the radius of curvature in the major axis direction of the phosphor screen is about 100,000 mm has been described. However, the present invention is not limited to the above radius of curvature, and the inclination angle of the neck determined by the radius of curvature is sufficient. It can be set in a small range. Further, the radius of curvature is not necessarily required to be a single curved surface, but may be a complex curved surface having a plurality of radii of curvature or a curved surface represented by a polynomial. The present invention is characterized in that the radius of curvature in the major axis direction is extremely large, and the radius of curvature can be approximated to infinity. On the other hand, the radius of curvature in the short axis direction does not affect the tilt angle of the neck, so that it can be freely selected in consideration of the atmospheric pressure intensity and the like, and similarly to the long axis direction, a single curved surface, a composite curved surface, a polynomial display, etc. A curved surface or the like can be appropriately selected.

In the present invention, the outer shape of the glass panel is not specified, but can be freely selected in consideration of the strength of the glass panel, reflection of external light, and the like. Although the present embodiment has described a cathode ray tube having a structure without a shadow mask, the present invention does not require the presence or absence of a shadow mask.
Further, the present invention can be applied to other methods such as a beam index. Also, the screen division in the long axis direction has been described for the case of two screens and three screens, but the present invention is also applicable to the case of four or more screens.

[0023]

The phosphor screen formed on the inner surface has a horizontally-long, substantially rectangular glass panel, a vacuum valve comprising a funnel having a plurality of glass necks having an electron gun therein, and a deflection provided on the funnel. Equipment,
In a cathode ray tube that scans the phosphor screen by dividing the phosphor screen into a plurality of regions by using an electron beam emitted from the electron gun, the glass panel has a radius of curvature in a major axis direction of the phosphor screen that is almost infinite, and is short. The neck is composed of a substantially cylindrical curved surface having a constant curvature in the axial direction, and the necks are arranged only in the long axis direction and are parallel to each other, so that normal axes passing through the centers of the respective divided regions are parallel to each other. The electron gun and neck located above are also parallel to each other. Accordingly, the raster of each divided area is symmetrical in up, down, left, and right directions, and connection of two screens is simplified. 2
Raster symmetry is important in simplifying the connection of screens. It goes without saying that the ideal phosphor screen shape is a flat surface that has no curvature in both the short axis and long axis. Generally, it is difficult for a glass panel having a screen to obtain sufficient strength against an atmospheric pressure load, particularly in a large-sized cathode ray tube, and it is inevitable to increase the thickness and weight of the glass. In general, the glass panel of a large cathode ray tube has a substantially spherical shape protruding outward or a substantially cylindrical curved surface having a curvature only in the long axis direction in consideration of the above problem, and has a sufficient strength against atmospheric pressure load. Is added.
In the cathode ray tube which scans the phosphor screen by dividing the phosphor screen into a plurality of regions as in the present invention, it is necessary to achieve both the symmetry of each raster and the strength of the glass panel. A cylindrical curved surface having curvature was used. As described above, in the present invention, since the necks in which the electron guns are provided can be made parallel to each other, the design, manufacture, mounting, adjustment, and drive circuit of the deflection device can be simplified.

Further, the radius of curvature from the center to the vicinity of the short side in the major axis direction is substantially infinite, the radius of curvature is constant in the vicinity of the short side, and the curvature is substantially cylindrical in the minor axis direction. In order to improve the strength of the glass panel against atmospheric pressure load, to secure the symmetry of the raster at the joint of the divided screens, to easily and smoothly connect the divided images, and to arrange the necks in parallel with each other By doing so, the design, manufacture, mounting, adjustment, simplification of the drive circuit and the like of the deflection device can be simultaneously realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a cathode ray tube according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a cathode ray tube according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a cathode ray tube according to a third embodiment of the present invention.

FIG. 4 is a structural diagram of a conventional cathode ray tube.

[Explanation of symbols]

 14 Glass panel 16 Funnel 17 Neck 18 Vacuum valve

 ──────────────────────────────────────────────────の Continuing from the front page (72) Kumio Fukuda, Inventor Kumao Fukuya 1-9-2 Hara-cho, Fukaya-shi, Saitama

Claims (3)

[Claims] 1. A vacuum panel comprising: a glass panel in which a phosphor screen formed on an inner surface is horizontally long and substantially rectangular; a vacuum valve comprising a funnel having a plurality of necks having an electron gun therein; and a deflecting device provided on the funnel. In a cathode ray tube which scans the phosphor screen by dividing the phosphor screen into a plurality of regions by an electron beam emitted from the electron gun, the glass panel has a curvature radius in a major axis direction of the phosphor screen substantially infinite. A cathode ray tube comprising a substantially cylindrical curved surface having a constant curvature in a short axis direction, wherein the necks are arranged in a long axis direction and are parallel to each other. 2. A vacuum panel comprising: a glass panel in which a phosphor screen formed on the inner surface is horizontally long and substantially rectangular; a vacuum valve comprising a funnel having a plurality of necks having an electron gun therein; and a deflecting device provided on the funnel. In a cathode ray tube that scans the phosphor screen by dividing the phosphor screen into a plurality of regions by an electron beam emitted from the electron gun, the glass panel extends from the center to the vicinity of the short side in the major axis direction of the phosphor screen. The radius of curvature is almost infinite, has a constant radius of curvature near the short side, and has a substantially cylindrical curved surface with a constant curvature in the short axis direction, and the necks are arranged in the long axis direction and are parallel to each other. A cathode ray tube characterized by the above-mentioned. 3. The cathode ray tube according to claim 2, wherein the radius of curvature in the major axis direction in the region from 80% to 95% from the center to the vicinity of the short side is substantially infinite, and the remaining region in the vicinity of the short side is made infinite. A cathode ray tube having a constant radius of curvature.