JPH0719537B2 - Color cathode ray tube - Google Patents

Description

The present invention relates to a color cathode ray tube and a method for manufacturing the same, and more particularly to a color cathode ray tube having a dot-shaped fluorescent surface and an exposure method used for forming the fluorescent surface.

Conventionally, a fluorescent surface of this kind has been exposed by continuously rotating a point light source. For this reason, the light spots formed on the fluorescent surface have the same shape as the hole shape of the shadow mask.As a result, the position and shape of the fluorescent surface dot are different from the irradiation position and shape of the electron beam, especially in the peripheral portion of the panel. However, there is a drawback in that it is difficult to adjust them, and the range of position adjustment of the deflection yoke in the subsequent process is narrowed.

The present invention has been made to overcome such drawbacks of the prior art, and its object is to have a dot-shaped fluorescent surface having a large position and shape latitude with respect to an electron beam spot, and It is an object of the present invention to provide a color cathode ray tube capable of improving the purity and the production yield and a method for producing the same.

In order to achieve such an object, the present invention provides a negative type dot fluorescent surface having a fluorescent surface dot with a diameter smaller than the electron beam diameter, in which the shape of the dot has a minor axis in the panel radial direction and a major axis in the tangential direction. And has a longitudinal direction that is symmetrical with respect to the rotation axis and is perpendicular to the rotation axis, and that exposes while rotating the rotating light source located in water by 180 ° or more. Is to be formed. Hereinafter, the color cathode ray tube and the method for manufacturing the same according to the present invention will be described in detail with reference to examples.

FIG. 1 is an explanatory view showing a fluorescent surface in an embodiment of the color CRT according to the present invention. As shown in the figure, the dots D of each color forming the fluorescent surface have an elliptical shape with a minor axis in the radial direction of the panel and a major axis in the tangential direction, and are substantially circular in the center of the panel. On the other hand, the shape becomes flatter as it gets farther from the center.

For the fluorescent surface of the color CRT having the above configuration,
The electron gun is located substantially at the geometrical center when viewed from the fluorescent surface side, and the electron beam emitted from the electron gun is deflected horizontally and vertically from the geometrical center by the deflection yoke. Land on. Therefore, in the step of adjusting the position of the deflection yoke, when the deflection yoke is moved in the direction of the central axis substantially perpendicular to the panel fluorescent surface, the deflection position of the electron beam is changed, and the landing position of the electron beam is changed accordingly. The panel tends to shift from the center in the radial direction of the panel. Therefore, when the fluorescent surface dot has an elliptical shape with a short diameter in the radial direction, as shown in FIG. 2, there is no chipping due to mislanding of the electron beam spot EB with respect to the dot D. the missing tolerance a _R, so that the dots D, can be increased as compared to the case not having such a flat shape.

Such a fluorescent surface can be formed as follows by using the apparatus shown in FIG.

That is, FIG. 3 shows an example of an exposure apparatus used for manufacturing a color cathode ray tube according to the present invention. In the figure, a light source section including a light source 2 made of an extra-high pressure mercury lamp and a lamp house 3 holding and fixing the light source is arranged below the inside of the apparatus housing 1. This light source unit is arranged on a rotary table equipped with a bearing unit 4 and a drive motor 5 for rotating the light source unit. On the other hand, on the upper part of the apparatus housing 1, a panel 6 is positioned and placed on a plate 7 so as to face the light source section, and a correction lens 8 and a filter are provided between the panel 6 and the light source section. 9 are arranged. Also, panel 6
A shed mask 10 is attached to the.

Here, the light source 2 is, as shown in FIG.
And the outer tube 2b, and the outer wall of the outer tube 2b is covered with a shroud 2c.
Is installed. Therefore, substantially, the portion of the opening of the shroud plate 2c facing the panel 6 has a function as an exposure light source, and this portion is symmetrical with respect to the rotation axis l of the rotary table. And has a long axis perpendicular to the rotation axis l. Further, around this light source 2, cooling water 11 is filled. In the figure, 3a is a glass plate provided on the surface facing the panel 6 of the lamp house 3 in FIG. Further, FIGS. 7A and 7B show the case where the light sources 2 are viewed from different directions by 90 °.

In the exposure apparatus having the above-mentioned configuration, the light beam emitted from the light source section passes through the correction lens 8 and the filter 9, and further through the shadow mask 10 to expose the inner surface of the panel 6.
In this case, as shown in FIG. 4, the light beam emitted from the light source 2 passes through the water 11 having a refractive index of approximately 1.343 and 1.469 and the glass plate 3a into the air having a refractive index of approximately 1.0.
Therefore, when the light source 2 is viewed from one point on the inner surface of the panel 6 as the exposed surface, the substantial center 2A, 2 of the exposure light source
B is apparently located at positions 2A 'and 2B'.

As described above, since the light source 2 is set in the water, the substantial exposure light source appears to be displaced from the original position with respect to the exposed surface of the panel 6, and the displacement is in the direction in which the light source 2 is viewed. Therefore, the size of the exposure light source differs depending on the viewing direction because the substantial exposure light source has a rectangular shape that is long in one direction defined by the shield plate 2c.

FIG. 5 shows such a shift state. In the figure, when the major axis direction of the light source 2 is parallel to the y axis as shown in (a1), that is, when the rotation angle θ = 0, the figure (a1)
As shown in 2), at point A in the direction corresponding to FIG. 4 (a), the exposure spot deviates from the original position toward the center O of the panel 6 by 15 μ in the −X direction as indicated by the vector. Appear in the position. Similarly, at a point B in the direction corresponding to FIG. 4 (b), as shown by the vector, it appears at a position shifted toward the outside of the panel 6 by 40 μ in the + y direction. Also, at a point C which is in the middle of the two, there is a shift corresponding to the vector sum of and. Next, as shown in FIG. 5 (b1), when the light source 2 rotates with respect to the y-axis and becomes θ = 45 °, as shown in FIG. 5 (b2), points A and B The exposure spots at points C and C are in the + y direction as indicated by and, respectively.
25μ, 30μ in + x direction and in the direction of vector sum of both
It deviates by 40μ. Then, as shown in FIG. 5 (c1), θ = 90
In case of ゜, as shown in the figure (c2), point A,
The exposure spots at the points B and C are shifted by 40 .mu. In the + x direction, 15 .mu. In the -y direction and 45 .mu. Next, when θ = 135 ° as shown in FIG. 5 (d1), the exposure spots at points A, B and C are respectively and as shown in FIG. 25μ in the -y direction,-
It is shifted by 30μ in the x direction and 15μ in the direction of the vector sum of the two. Further, when θ = 180 °, the displacement of the exposure spot becomes the same as in FIG. 5 (a2).

As described above, when the light source 2 is rotated 180 °, the center of the exposure slot is rotated 360 ° on the inner surface of the panel, and the deviation amount from the original position is different depending on the direction.

FIG. 6 shows the exposure intensity distribution according to the total amount of light irradiated to the point A while the light source 2 is rotated 180 °. In the figure, in the radial direction Ra (in this case, the x direction), the exposure intensity distribution changes from (a) to (b), and the exposure intensity distribution as a whole is obtained as shown in (c). On the other hand, in the tangential direction Ta (y-axis direction in this case), the exposure intensity distribution changes from (d) to (e),
An exposure intensity distribution as shown in (f) is obtained as a whole. Therefore, if the exposure intensity required to produce a desired change in the photosensitizer on the inner surface of the panel is f, as shown in (g) of the figure, a minor axis b in the radial direction and a major axis a in the tangential direction. An elliptical dot having Elliptical dots are similarly obtained at other points on the inner surface of the panel. In this case, the ellipse becomes flat as the ratio a / b of the major axis to the minor axis becomes larger toward the peripheral portion of the panel, and a substantially circular dot is obtained at the central portion. Therefore, it becomes possible to form a negative type dot fluorescent surface having an elliptic fluorescent surface dot as shown in FIG.

Further, in this case, in order to obtain the above-mentioned elliptic dot, the light source 2 does not need to rotate 360 °, but 180 ° is sufficient. Therefore, compared to the conventional continuous rotation method, it becomes easier to supply a high-voltage power source and cooling water to the rotating portion, and the mechanism can be simplified.

The ratio of the minor axis to the major axis of the oval dot can be controlled by a method of changing the distance from the inner surface of the panel of the light source 2 in synchronization with the rotation of the light source 2. Figure 7 shows
An example of an exposure apparatus used in such a method is shown, and the same portions as those in FIG. 3 are denoted by the same symbols and detailed description thereof is omitted. That is, in FIG. 7, the plate cam 12 is provided below the rotary shaft.
And its drive motor 13 are disposed, and a follower 14 that moves in contact with the plate cam 12 is attached to the tip of the rotary shaft. Therefore, by rotating the plate cam 12 in synchronism with the rotation of the rotary shaft 4, the light source 2 is moved up and down to move the panel 6 thereof.
The distance to the inner surface of the can be varied.

Incidentally, in the above-described examples, the photosensitizer applied to the inner surface of the panel which is exposed to an elliptical shape is a phosphor slurry in a so-called slurry method, and is powdered using a photoadhesive substance that exhibits adhesiveness by exposure. It is needless to say that the photoadhesive substance is used in the method of forming the fluorescent surface by attaching the fluorescent substance in the form of a circle.

As described above, according to the color cathode-ray tube and the manufacturing method thereof according to the present invention, by exposing while rotating a light source arranged in water, an elliptical silica having a minor axis in the panel radial direction and a major axis in the tangential direction. Light surface dots can be formed. Therefore, especially in the peripheral portion of the panel, it is possible to improve the tolerance of the fluorescent surface dots with respect to the electron beam spots, so that it is possible to improve the color purity and the manufacturing yield of the color CRT. Have.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a fluorescent surface in an embodiment of a color cathode ray tube according to the present invention, FIG. 2 is an explanatory view showing a relationship between the fluorescent surface dots and electron beam spots, and FIG. FIG. 4 is an explanatory view showing an internal structure showing an example of an exposure apparatus used for implementation, FIG. 4 is an explanatory view showing a light source section thereof, FIG. 5 is an explanatory view showing a relation between rotation of the light source section and an exposure spot, and FIG. Explanatory drawing which shows the relationship between an aisle and a to-be-exposed part, 7th
The figure is an internal structure diagram showing another example of the exposure apparatus used for carrying out the present invention. D ... Dot, EB ... Electron beam spot, 2 ... Light source, 2a ... Arc tube, 2b ... Outer tube, 2c ... Sheath plate, 3
...... Lamp house, 3a …… Glass plate, 4 …… Bearing part, 5
...... Drive motor, 6 …… Panel, 10 …… Sheep mask, 11 …… Water, 12 …… Plate cam, 13 …… Drive motor, l…
…Axis of rotation.

Claims (1)

[Claims] 1. A color cathode-ray tube having a negative type fluorescent surface having a fluorescent surface dot having a diameter smaller than an electron beam spot diameter, wherein the shape of the fluorescent surface dot has a minor axis in a panel radial direction and a tangential direction. A color cathode-ray tube characterized by having a long diameter.