JPS588541B2 - color picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to color picture tubes, and more particularly to an improved color picture tube having a striped fluorescent surface.

In general, the fluorescent surface of a shadow mask type color picture tube used in a television receiver, for example, is opposed to the inner face of a front glass panel coated with a photosensitizer, and has a shadow mask structure formed with a large number of through holes. placed at appropriate intervals.

Furthermore, the fluorescent surface is exposed to light by irradiating the photosensitizer on the inner surface of the face from a predetermined position through this shadow mask structure using a light source consisting of, for example, a mercury lamp that emits strong ultraviolet rays.

Three black matrix holes are formed in one through hole of the shadow mask structure by a so-called photographic method, and then, for example, phosphors of the three primary colors of red, blue, and green are baked, respectively. The area around the phosphor is filled with black material.

Alternatively, without forming the black matrix hole, the phosphor is formed directly on the inner surface of the face of the panel using a photographic method.

When the shadow mask structure has slot-shaped through holes, a fluorescent surface, particularly a striped fluorescent surface (hereinafter simply referred to as a fluorescent surface), which is excellent in brightness, landing characteristics, etc. can be obtained.

FIG. 1 is a perspective view including a partially enlarged view of a shadow mask structure of a conventional color picture tube.

FIG. 2 is a partially enlarged view showing the shape of the holes in the shadow mask perforated plate.

With reference to FIGS. 1 and 2, shadow mask structure 1
The shadow mask perforated plate '2 is provided with a large number of through holes 4 in the areas corresponding to the effective diameters a and b through which the fluorescent surface created through the plate has a predetermined size, and this shadow It is composed of a substantially rectangular frame 3 that supports a mask perforated plate.

The through holes 4 are formed in a vertical line with bridges 5 interposed therebetween, with the major axis direction corresponding to the direction perpendicular to the fluorescent surface.

Further, the through holes 4 are arranged in a staggered manner with the pitch of the bridges 5 being shifted by 1/2 in each row in order to minimize the adverse effect that the bridges 5 have on the quality of the color picture tube.

Here, as shown in FIG. 2, the shadow mask perforated plate 2
The outer end C of the long side of the through hole 4 is not a straight line, but usually has a radius of curvature of several thousand millimeters R, corresponding to the violet light surface.

Therefore, the through hole 4 may have a long slot shape, a short slot shape, or may overlap the bridge 5 portion.

Further, since the through hole 4 is formed by etching, the outer end C on the long side may have an uneven shape with respect to a circular arc having a predetermined radius of curvature.

FIG. 3 is a partially enlarged view showing a portion of a conventional fluorescent surface.

The striped phosphor 6 shown in FIG. 3 is formed by alternately printing phosphors of the three primary colors of red, blue, and green.

This fluorescent surface 9 is formed on the inner face of the panel (not shown), and includes three red, blue, and green striped fluorescent bodies 61, 6.
2.63 corresponds to one through hole 4.

As shown in FIG. 3, the effective end d of the phosphor surface exposed and created through the shadow mask perforated plate 2 having such a through-hole 4 is a step where the striped phosphor 6 is partially discontinuous. The quality of the fluorescent surface deteriorates because it is formed in a shape.

Furthermore, the stripe phosphor corresponding to the part where the through hole 4 at the outer end C shown in FIG. had the disadvantage of being easy to peel off.

Therefore, the main object of the present invention is to provide a color picture tube having a high-quality fluorescent surface whose manufacturing process is highly reliable.

In summary, the present invention includes a panel and a shadow mask structure disposed opposite to the inner surface of the face of the panel, the shadow mask structure including at least a first mask provided with a plurality of slotted through holes. The color picture tube is provided with a second mask that suppresses the periphery of the through hole in the vicinity of the outer end, respectively, at the outer end of the through hole of the first mask in the major axis direction.

The above objects and other objects and features of the invention will become more apparent from the following detailed description with reference to the drawings.

FIG. 4 is a schematic cross-sectional view of a shadow mask structure according to an embodiment of the present invention.

Referring to FIG. 4, the shadow mask structure 1 includes a substantially rectangular frame 3 having locking means (not shown) that can be disposed at appropriate intervals facing the inner face of a panel (not shown). , a shadow mask perforated plate 2 as a first mask formed into a spherical shape corresponding to the inner surface of the face of the panel and with the major axis of the slot-shaped through holes 4 arranged in a direction corresponding to the vertical direction of the fluorescent surface; For example, it is fixed by welding.

In the vertical direction, that is, on the long side, of the first mask, that is, the shadow mask perforated plate 2, a through hole 4 is provided over a range larger than the required outer end diameter (effective diameter).

Furthermore, a second mask 7 whose tip part is formed so as to cover a part of the outer end part of the through hole 4 and has an opening diameter smaller than the diameter of the outer end part is provided on each long side, for example. Fixed by welding.

When the shadow mask assembly 1 configured as described above is disposed on the inner surface of the panel and exposed by a known method, a portion of the light rays that have passed through the through holes 4 of the shadow mask perforated plate 2 are transmitted to the second
It is blocked by the tip of the mask 7.

That is, the irradiation area of the light beam that determines the outer end in the long axis direction of the through hole 4, that is, the outer end on the long side, is the shadow mask perforated plate 2.
is determined by the second mask 7, regardless of the shape of the outer end of the through hole 4, etc.

The exposure light passes through an area corresponding to the effective diameter of the fluorescent surface determined by the aperture diameter at the tip of the second mask 7, and is irregularly distributed on the outer end of the long side of the shadow mask perforated plate 2. To eliminate the adverse effects of short slot-shaped or long slot-shaped through holes 4, etc. that may occur when creating a fluorescent surface.

FIG. 5 is an enlarged view showing a part of the fluorescent surface according to this embodiment.

As shown in FIG.
After creating a hole or using a black matrix
A striped phosphor 8, which is printed without creating holes, is formed so as to correspond to the second mask 7 and is cut into a smooth curved line with no irregularities along an arc having a predetermined radius of curvature. Ru.

Therefore, an extremely high-quality phosphor surface can be obtained, and it is possible to eliminate partial peeling due to differences in adhesive strength of the striped phosphors caused by the through holes 4 at the outer end of the perforated shadow mask plate 2. .

Note that even if the tip of the second mask 7 is fixed to the frame 3 so as to be tightly attached to the outer edge of the first mask 2, this effect can be obtained to some extent;
When irradiating the photosensitizer on the inner surface of the face, it is best to leave as much space as possible in order to eliminate the shadow caused by the bridge (not shown) of the shadow mask perforated plate 2 due to the penumbra of the light beam passing through the through hole 4. is desirable.

In addition, in the above embodiment, only the long axis direction (long side) of the through hole of the shadow mask structure corresponding to the vertical direction of the fluorescent surface was described, but the short axis direction of the through hole corresponding to the horizontal direction of the fluorescent surface was described. It can also be applied in the radial direction (short side).

As described above, according to the present invention, by disposing the second mask in the shadow mask structure, the adhesion strength of the phosphor is strong in the step of creating a striped phosphor, and it is not peeled off during development. In addition, a color picture tube having a high-quality phosphor surface whose effective end is formed along a curve with a predetermined radius of curvature can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged perspective view of a shadow mask structure of a conventional color picture tube. FIG. 2 is a partially enlarged view showing the shape of the holes in the perforated shadow mask plate. FIG. 3 is a partially enlarged view of a conventional fluorescent surface. FIG. 4 is a sectional view showing an outline of a shadow mask structure which is an example of the present invention. FIG. 5 is a partially enlarged view showing a part of the fluorescent surface according to this embodiment. In the figure, 1 is a shadow mask structure, 2 is a shadow mask perforated plate (first mask), 3 is a frame, 4 is a through hole,
7 indicates the second mask.

Claims (1)

[Scope of Claims] 1. A color picture tube comprising a panel and a shadow mask structure disposed opposite to the inner surface of the face of the panel, the shadow mask structure having a plurality of slot-like through holes. 1. A color picture tube comprising: a first mask; and a second mask that prevents access to an outer end portion of at least one of the major diameter direction and the minor diameter direction of the first mask.