JP2653318B2 - Color cathode ray tube - Google Patents

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 having a shadow mask.

[0002]

2. Description of the Related Art FIG. 1 is a sectional view of a panel portion of a shadow mask type color cathode ray tube. In the figure,
Reference numeral 1 denotes a glass panel constituting a part of the vacuum vessel, which is formed in a substantially spherical shape so as to have a convex curved surface toward the outside, and has a fluorescent layer 2 on its inner surface. Reference numeral 3 denotes a shadow mask arranged at a predetermined distance from the fluorescent layer 2 and has a curved surface portion 3a and a skirt portion 3b, and a large number of through holes 4 are formed in the curved surface portion 3a in a regular arrangement. . In addition,
The shadow mask 3 is held inside the panel 1 by a holding mechanism (not shown).

In the above structure, the area where the fluorescent layer 2 is formed on the inner surface of the panel 1 is called an effective screen 2a, and the area where the through hole 4 is formed on the curved surface 3a of the shadow mask 3 is a perforated part 4a. The effective screen 2a has a perforated portion 4a.
Is a kind of enlarged projection shape. That is, the electron beam during the operation of the color cathode-ray tube approximately travels straight from a virtual point D called a deflection center, and as shown by a two-dot chain line in FIG. The light passing through the perforated phosphor line 4b collides with the fluorescent layer phosphor line 2b surrounding the effective screen 2a.

FIG. 2 shows three views of a shadow mask 3 used for a color cathode ray tube. The curved surface portion 3a and the skirt portion 3b of the shadow mask 3 are integrally formed by press-forming a thin metal flat plate generally called a flat mask. FIG. 3 shows an example of such a flat mask. The flat mask 13 has a substantially rectangular perforated portion 4a in which a large number of through holes 4 are formed in a regular array, and the periphery of the perforated portion 4a forms a perforated phosphor line 4b. . In addition, a perforated portion 13b having no through hole 4 is provided on the periphery of the perforated portion 4a.

When the flat mask 13 is press-formed to obtain the shadow mask 3 shown in FIG. 2, if the perforated line 4b of the flat mask 13 becomes the perforated line 4b of the shadow mask 3 as it is. It is good, but in reality, the shape of the flat mask 13 usually does not completely match due to the fact that the plane of the flat mask 13 changes to a curved surface by press molding and the material elongates at the time of press molding. .

Recently, the radius of the inner and outer surfaces is significantly larger than that of the conventional one, and the shape of the effective screen 2a, ie, the phosphor layer line 2b, as shown in FIG.
However, when this was observed from a sufficiently far front, a color cathode ray tube having an almost perfect rectangular shape and each side of which was almost a perfect straight line came to be produced. And
In manufacturing such a color cathode ray tube, a flat mask in which each side of a perforated phosphor line is a straight line has conventionally been used.

[0007]

However, when such a flat mask 13 is press-formed, as described above, the perforated line 4b of the flat mask 13 and the perforated line 4b of the shadow mask 3 after press forming are formed. 4b does not match,
As shown in FIG. 5, the perforated line 4b of the shadow mask 3 may have a so-called barrel shape that bulges outward and has a panel radius different from the conventional one. (The change in the state of press projection due to the change in the state of the enlarged projection and the change in the curved shape of the shadow mask due to the fact that the panel radius has changed from the past) due to the use of the shadow mask 3 In the color cathode ray tube used, it was found that the phosphor layer line 2b was not formed in a perfect rectangular shape but in a barrel shape, and the design value was often impaired. The present invention has been made in view of the above circumstances. When a substantially rectangular phosphor layer is viewed from a sufficiently long distance, two opposite sides of the phosphor line are viewed as straight lines, and the effective screen is formed into a rectangular shape. It is an object of the present invention to provide a color cathode ray tube which has an improved design by approaching the color cathode ray tube.

[0008]

In order to achieve the above object, a color cathode ray tube according to the present invention is provided on a flat metal plate.
Almost rectangular shape with many holes formed in a regular array
But at least one pair of opposing sides is the center of itself
A curved perforated line that is concave toward
Press-formed shadow of the formed flat mask
Mask and fluorescent light formed using this shadow mask
Panel with a layer on the inner surface and curved outward.
A color cathode ray tube having a color cathode ray tube.
When the panel is viewed from the front, the phosphor layer of the phosphor layer is rectangular
The shadow mask has a predetermined convex curved surface so that
Press molded and specified for the inner surface of the panel
Is held at the position shown in FIG.

[0009]

According to the present invention, a metal plate having a substantially rectangular perforated portion is formed so as to be outwardly formed into a predetermined curved surface by press forming, and a panel of the obtained shadow mask and thus a fluorescent plate. By maintaining a predetermined distance from the layer, at least a pair of opposing sides can be seen to be linear when the shape of the effective screen is observed from a sufficiently far front.

[0010]

【Example】

Embodiment 1 FIG. Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 6 shows a flat mask 13 according to an embodiment of the present invention. As is apparent from the drawing, the perforated scribe line 4b has a so-called pincushion-shaped curved shape that is depressed toward the center O of the perforated portion 4a. When such a flat mask 13 is used, even if the shape of the perforated line 4b is slightly deformed into a barrel shape when the flat mask 13 is press-formed, the perforated line 4b of the formed shadow mask 3 is formed.
4b allows each side to be a straight line.

However, as described with reference to FIG. 1, the phosphor layer line 2b is one of the perforated line lines 4b of the shadow mask 3.
Although this is a kind of projection enlargement, the shape of the perforated line 4b of the shadow mask 3 is similar to the shape of the perforated line 4b of the shadow mask 3 depending on the inner surface shape of the panel 1 and the relationship between the panel 1 and the curved surface 3a of the shadow mask 3. It is not usually enlarged. Therefore, in order to ensure that each side of the phosphor layer line 2b of the completed color cathode ray tube becomes a perfect straight line when viewed from a sufficiently distant front, a flat line is required in advance to allow for the deformation due to the above-described projection enlargement. It is necessary to design a mask. However, even if such a possibility of deformation is considered, or if such a possibility is taken into consideration, the shape of the phosphor layer line 2b that is finally formed is such that each side seen from a distance from the front is a straight line. It has been experimentally confirmed that there is a case where the perforated line 4b of the flat mask 13 is preferably formed in a pincushion shape as described above.

Since the top and bottom and the left and right of the flat mask 13 are symmetrical, as shown in FIG. 6, the center line in the longitudinal direction passing through the center O is the x-axis, and the x-axis is passed through the center O. If the center line orthogonal to
The short side and the long side of 4b are represented by functions x = f (y) and y = g (x), respectively. Now, considering only the quadrant of x ≧ 0 and y ≧ 0, the condition for the shape of the perforated drawn line 4b to be a pincushion condition is as follows. d ² f / dy ² > 0 On the short side, x can be expressed as d ² g / dx ² > 0 at or near x = 0.

In the above embodiment, the perforated line 4b has a pincushion shape for both the short side and the long side, but either one may be used. When applied to the short side, the outermost rows of the perforations 4 may be arranged such that the outermost row on the short side of the perforations 4 appropriately draws a curve along the perforated line 4b. In this case, when x = 0, the arrangement direction of the through holes 4 should coincide with the y-axis.
It is preferable that the arrangement of the through holes 4 be made closer to a straight line as the distance from the hole approaches. The same can be said for the long side.

[0014]

As described above, according to the present invention, the flat
Many through-holes were formed in a regular array on a flat metal plate
It is generally rectangular, but at least one pair of opposing sides
Curved perforated part that is concave toward the center of itself
Press-molding a flat mask with phosphorus lines
Using a shadow mask
Having a fluorescent layer formed on the inner surface,
A color cathode-ray tube with a panel made
When the color cathode ray tube panel is viewed from the front, the fluorescent layer
So that the shadow line becomes a rectangle.
Is press-formed with a predetermined convex surface and
So that it is held in place against the inner surface of the panel.
As a result, the effective screen shape can be viewed from the front as a result.
Can be made rectangular, thereby improving the design.
There is an effect that can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a panel portion of a shadow mask type color cathode ray tube.

FIG. 2 is a three-sided view of a shadow mask.

FIG. 3 is a front view of a flat mask.

FIG. 4 is a front view of a panel having a rectangular effective screen.

FIG. 5 is a diagram showing an example of the shape of a perforated phosphor line after forming a flat mask used in a conventional color cathode ray tube.

FIG. 6 is a front view of a flat mask used in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Panel 2 Phosphor layer 2b Phosphor layer phosphor line 3 Shadow mask 4 Through hole 4a Perforated part 4b Perforated phosphor line 13 Flat mask O Center of perforated part

Claims (1)

(57) [Claims] 1. A large number of through holes are regular in a flat metal plate.
Almost rectangular shape, but at least one pair
The opposite side of is concave toward its own center
Flat mask with curved perforated lines
A shadow mask formed by press molding, and a fluorescent layer formed using the shadow mask
Having a panel with a convex curved surface toward the outside
A color cathode ray tube, wherein the color cathode ray tube panel is seen from the front when the panel is viewed from the front.
Make the shadow above the shadow so that the outline of the light layer is rectangular.
The mask is press-formed with a predetermined convex surface and
At a predetermined position with respect to the inner surface of the panel.
A color cathode ray tube characterized by the above-mentioned.