JPS6243300B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an index type in which a stripe-like phosphor of three colors and a stripe-like index pattern parallel to the phosphor are formed by exposure using one mask having a transparent part. This paper relates to a method for forming a phosphor screen in a color cathode ray tube, and particularly aims to simplify the exposure system and improve the accuracy of phosphor screen formation.

As is well known, the index type color cathode ray tube has three colored striped phosphors 2 [2R, 2G and 2
B] and a striped carbon layer 3 for light absorption, and a striped index pattern 5 for detecting the position of the scanning beam via a metal back layer 4 formed by vapor deposition of a metal such as aluminum.
is coated. The striped phosphor 2 and the striped index pattern 5 are formed with different pitches. Conventionally, as a method of selectively exposing the striped phosphor 2 and the striped index pattern 5 with different pitches, one exposure mask was used to expose the striped phosphor 2 and the striped index pattern 5 with different pitches. A method of forming the Tux pattern 5 by exposure has been proposed.

In this method, as shown in FIGS. 2 and 4, pitches P ₁ and 3 of the striped index pattern 5 are
The position of the light source 10 is determined by using a mask 7 having a transparent portion 6 with a pitch P ₃ that is the least common multiple of the pitch P ₂ of the colored striped phosphor 2, and through an exposure adjustment filter 8 and a correction lens system 9. The phosphors 2 and the index patterns 5 are exposed and formed by moving the phosphors 2 and the index patterns 5 to the left and right in several steps (9 steps in this example). Normally, two exposure masks with different pitches are required, one for phosphor 2 and one for index pattern 5, but with this method, one common exposure mask can be used to expose both phosphor 2 and index pattern 5. This has the advantage of preventing misalignment due to mask alignment and making work easier.

However, in this method, the amount of movement of the light source 10 is large because it requires at least nine steps of light source movement, and as shown in FIG.
In a portion where the incident angle of 1 is large, the stripes are blurred due to the influence of the penumbra t, and the stripe width d is inevitably non-uniform.

Furthermore, the grouping phenomenon caused by moving the light source 10, that is, if the light source 10 is positioned on the axis Y passing through the center of the panel, the pitch of the stripes during exposure can be compensated for over the entire area of the panel 1. ,
A correction lens system 9 is required to correct a phenomenon in which the pitch of the left and right stripes differs around the central axis Y when the light source 10 moves.

In view of the above points, the present invention improves the above-mentioned drawbacks of using a single exposure mask, enables high-precision exposure, and simplifies the exposure system by omitting the correction lens system. The present invention provides a method for forming a phosphor screen of an index type color cathode ray tube.

Hereinafter, the present invention will be explained with reference to examples.

As shown in FIGS. 5 to 7, the inner surface of the panel 1 of the index type color cathode ray tube is formed into a cylindrical surface or a curved surface approximating the cylindrical surface (the radius of curvature in the longitudinal direction in which the striped phosphors 2 extend). The exposure mask 7 is also formed as a whole into a cylindrical surface or a curved surface approximating it. When forming the three-color striped phosphor 2 [2R, 2G, and 2B], the striped carbon layer 3, and the striped index pattern 5 by exposure, the pitch _P2 of the phosphor 2 and the pitch P of the index pattern 5 are determined. An exposure mask 7 in which a transparent part 6 is formed with a pitch P ₃ that is the least common multiple of ₁ is placed facing the inner surface of the panel 1, and a filter 8 for adjusting the exposure amount is placed. The light source 10 placed at a position corresponding to the center of deflection is fixed, and the mask 7 is moved around its center of curvature O for exposure. That is, the light source 10 is fixed on the axis Y passing through the center of the panel 1,
For example, as shown in FIG. 6, the mask 7 is rotated about the center of curvature O of the mask 7 to a position where the transmitting part 6 corresponds to the red striped phosphor 2R to be exposed as seen from the light source 10, and the state is A red striped phosphor 2R is formed by exposure. Generally, the radius of curvature of the mask or panel is 3 to 4 times or more the distance between the light source and the mask or panel.
In the case of this phosphor 2R, as shown in FIGS. 6 and 7, the red striped phosphor 2R is exposed and formed at a predetermined pitch over the entire panel by performing the mask movement and exposure process twice. Note that the movement angle Δθ of one step of the mask 7 depends on the pitch _P2 of the phosphor 2, but in the case shown in the figure, the movement angle Δθ of one step is
The length of the moved arc is 1/ of the pitch P3 of mask 7.
12, and the mask 7 is moved by the required number of steps based on this movement angle Δθ. Moreover, since the movement of the mask 7 is performed along the curvature circumference of the mask 7, the movement of the mask 7 is performed along the circumference of the mask 7.
The distance between and panel 1 remains unchanged. Furthermore, Figure 6,
The reason why panel 1 and mask 7 are both drawn flat in Figure 7 is because a part of the phosphor screen and mask 7 are enlarged, and from a macroscopic perspective, the rotational movement of the mask is approximated by parallel movement. .

Next, in the same manner, the mask 7 is rotated to a predetermined position and the green and blue striped phosphors 2G and 2B are exposed to light 11 from the fixed light source 10. Note that the striped carbon layer 3 is formed by the reversal phenomenon of photosensitive stripes prior to the phosphor 2, as in the conventional case, but the exposure for curing treatment for forming the photosensitive stripes is the same as described above. Similarly, mask 7 is replaced with red, green and blue phosphors 2.
This is done by rotating and moving to positions corresponding to the positions where R, 2G, and 2B are to be formed.

Next, after forming the metal back layer 4, when forming the index pattern 5 by exposure, the same mask 7 is placed at the same position as above with respect to the inner surface of the panel, and the transparent part 6 of the mask 7 is similarly placed. Mask 7 corresponds to the position of index pattern 5.
It is rotated around the center of curvature O to perform exposure formation. In the case of this index pattern 5, 3
The index pattern 5 of a predetermined pitch is formed by exposure for the first time through multiple mask movements and exposure processing.

As the exposure mask 7, a so-called aperture grill (color selective electrode) type mask made by selectively etching a thin metal plate into a predetermined pattern may be used, or a predetermined pattern may be formed by metal vapor deposition or emulsion on a transparent glass substrate. It is also possible to use a mask in which the transparent portion 6 is formed.

The means for moving the exposure mask 7 can be constructed as shown in FIG. 8, for example. That is,
In the illustrated case, a substrate 14 having a transmission hole 13 for light from an exposure light source 10 is provided integrally with a mounting table 12 on which a panel 1 is placed at a position facing the inner surface of the panel. A guide 16 having a curved surface 15 concentric with the curved surface (cylindrical surface) of the mask 7 is provided. On the other hand, a mask moving table 19 that holds the mask 7 and has rollers 18 attached to the lower surface having the light transmission hole 17 is provided, and this is placed on the curved surface 15 of the guide 16, and the mask moving table 19 is guided through the rollers 18. 16. In this way, the mask 7 can be moved while keeping the distance from the inner surface of the panel unchanged, and can be rotated substantially around its center of curvature. Such a moving means is suitable for application to large pipes.

In addition, as shown in FIGS. 9 and 10, a leg portion 20 having a length corresponding to the radius of curvature of the mask 7 is provided on the mask moving table 14, and the lower end of this leg portion 20 is connected to a shaft 2.
1, or can be configured to be rotatably supported by a knife edge structure 22.

According to the above method, the light source 10 is fixed and the mask 7 is moved around its center of curvature to expose each phosphor 2 and the index pattern 5, so the angle of incidence of the light 11 on the mask 7 is small and half The influence of shadow areas is eliminated, and uniform stripe widths can be obtained in each area.

Further, by using this method, it is possible to bring the panel 1 and the mask 7 as close as possible, so that the penumbra is less likely to occur and a more accurate stripe width can be obtained. Incidentally, in the conventional case, when the panel and mask are brought close to each other, the amount of movement of the light source increases, making it difficult to design a correction lens system, and it is virtually impossible to perform exposure formation.

Furthermore, the light source 10 passes through the center of the panel 1 at an axis Y
Since the light source is fixed at the top, a grouping phenomenon based on the movement of the light source does not occur as in the conventional case, and therefore the correction lens system that was conventionally required can be omitted and the exposure system can be simplified.

FIG. 11 shows another embodiment of the invention. Assuming that the light source 10 and panel 1 are fixed,
Each phosphor 2, carbon layer 3, and index pattern 5 are exposed and formed by moving the mask 7 in ±△x parallel along the axis X perpendicular to the axis Y connecting the center of the panel 1 and the light source 10. This is the case if you do this. According to this method, since the amount of movement of the mask 7 parallel to the axis X is extremely small relative to the radius of curvature of the mask 7, Δx can be replaced with Δθ described in FIG. Thus, as in the case of FIG. 5, highly accurate exposure processing can be performed and the exposure system can be simplified. Furthermore, in the case of such a method, △x can be replaced with △θ, so this method is particularly advantageous when panel 1 is flattened (corresponding to one where the center of curvature is at infinity), and the above-mentioned Similarly, parallel movement of the mask enables exposure processing for each phosphor and index pattern, so compared to the movement means for rotational movement shown in Figs. 8 to 10, the movement for parallel movement (not shown) is possible. means are easily available,
The structure of the exposure apparatus can be simplified.

In the case of FIGS. 5 and 11, the mask 7 is moved, but the panel 1 may be moved instead of the mask 7. That is, as shown in FIG. 12, the mask 7 may be fixed and the panel 1 may be rotated around the center of curvature O' of the inner surface for exposure, or as shown in FIG.
It is also possible to expose by fixing the panel 1 and moving the panel 1 in parallel by ±Δx along an axis X perpendicular to the axis Y connecting the center of the panel 1 and the light source 10. The same effects as in FIGS. 5 and 11 can be obtained in FIGS. 12 and 13 as well.

As described above, when the present invention uses a single exposure mask to form striped phosphor and striped index patterns with different pitches, it is possible to expose the stripe width uniformly over the entire area. The accuracy of surface formation can be improved, and furthermore, the exposure apparatus can be simplified by omitting the correction lens system. Further, since the amount of movement of the mask 7 or the panel 1 is small and the light source 10 is arranged approximately on the central axis of the panel 1, the illuminance distribution over the entire panel 1 becomes uniform. Furthermore, since the mask 7 or panel 1 can be moved accurately, reproducibility is improved. Therefore, it is suitable for application to the manufacture of this type of index type color cathode ray tube.

In the above example, this was applied when the inner surface of the panel was a cylindrical surface or a curved surface approximating the same, but in other cases, the inner surface of the panel could be used not as a cylindrical surface but also in the vertical direction in which the phosphor stripes extend and in the horizontal direction perpendicular to the above. The present invention is also applicable to curved surfaces having respective required curvatures.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the main parts of the phosphor screen of an index type color cathode ray tube, Fig. 2 is a layout diagram showing the conventional exposure method, and Fig. 3 is a sectional view of the main parts to explain the exposure state. FIG. 4 is an explanatory diagram showing the occurrence of a penumbra during exposure, FIG. 5 is a layout diagram showing an embodiment of the method of the present invention, and FIGS. 6 and 7 are diagrams explaining the exposure state. FIGS. 8 to 10 are diagrams showing specific examples of moving means for the exposure mask, and FIGS. 11 to 13 are layout diagrams showing other embodiments of the method of the present invention, respectively. . 1 is a panel, 2 is a striped phosphor, 3 is a carbon layer, 5 is an index pattern, 7 is an exposure mask, and 10 is a light source.

Claims (1)

[Claims] 1. A mask in which a transparent portion is formed with a pitch that is the least common multiple of the pitch of the striped index pattern and the pitch of the striped phosphors of three colors is disposed facing the inner surface of the panel. , in a method for forming a phosphor screen of an index type color cathode ray tube, in which a striped phosphor and a striped index pattern are formed by exposure using the one mask, a single light source is fixed on the central axis of the panel; The panel or mask is relatively centered around its center of curvature or in parallel so that the transparent part of the mask corresponds to the striped phosphor to be exposed or the striped index pattern when viewed from a single light source. A method for forming a phosphor screen of an index type color cathode ray tube, characterized in that exposure is performed by moving the phosphor screen.