JPH0618104B2 - Method for forming fluorescent surface of color cathode ray tube - Google Patents

Description

The present invention relates to a phosphor screen forming method of a color cathode ray tube in which phosphors of three primary colors are sequentially printed and applied on a face plate to form a phosphor screen.

[Prior Art] FIG. 2 is a sectional view showing a main part of a beam index tube. In the figure, (1) is a face plate made of a flat glass plate. Carbon stripes bl are formed on the face plate (1), and red, green and blue color phosphor stripes R, G and B are sequentially formed therebetween. Further, an aluminum (Al) film (2) as a metal back is formed on the color phosphor stripes R, G, B, and an index phosphor stripe ID is further formed thereon.
Is formed. Further, (3) is a funnel, which is sealed to the end of the face plate (1) with a frit (4).

The applicant of the present invention has proposed to form the phosphor screen of such a cathode ray tube in the process shown in FIG. 3, for example.

First, as shown in FIG. 3A, a photosensitive phosphor paste (5) containing, for example, a blue phosphor is printed and applied only on a necessary portion on the carbon stripe bl. In the figure, (6) is a screen mesh and (7) is a squeegee.
For (6), for example, # 150 or more is used.

Next, as shown in FIG. 6B, after the printing is applied, it is left as it is, and is leveled and dried so that no printing mesh marks are left.

Next, as shown in FIG. 6C, a photosensitive phosphor paste
The portion of (5) where the blue phosphor stripe B is to be formed is exposed to ultraviolet rays (9) through the photomask (8) to cure the portion.

Next, as shown in D of the same figure, for example, development is performed with water (10).

As described above, the blue phosphor stripe B is formed. The red and green phosphor stripes R and G are also described above.
It is similarly formed in the step of.

[Problems to be solved by the invention]

Generally, the widths of the three primary color phosphor stripes R, G, and B are often the same, but the width of the green color phosphor stripe G having high visibility is widened or white balance is taken in order to obtain high brightness. For the three primary color phosphor stripes R,
The width of G and B may change. When the widths of the color phosphor stripes are different as described above, if the thick stripes are applied by printing, exposing, and then developing, the gap between the color phosphor stripes of the third color is narrowed, and the photosensitive phosphors are applied during print application. As it becomes difficult to fill the paste, as shown in Fig. 4, the part (1
There is an inconvenience that 2) occurs. For example, in the case of a single-tube projector using a beam index tube as described above, the width ratio of the color phosphor stripes R, G, B is 1: 1.
It is set to 6: 1. In that case, color phosphor stripes G → B
→ If it is formed in the order of R, when forming the stripe R,
Since the gap where the stripe R is formed is narrow, as shown in FIG. 5A, when the photosensitive phosphor paste (13) containing the red phosphor is printed and applied, the gap where the stripe R is formed is formed. As shown in FIG. 5B, the stripe R after the exposure and development may not be sufficiently filled, and the stripe R may be lacking in the central portion or may be completely absent. The moving direction of the squeegee is the same as the stripe direction.

Therefore, in the present invention, the lack of the colored phosphor is not generated on the phosphor screen.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention forms the phosphors of the three primary colors of red, green, and blue by printing and coating the phosphors of the colors having a large coating area at the end. For example, in the case where the phosphor screen is not the three primary color phosphor stripes R, G, B, a stripe having a wide stripe width is formed last.

[Action]

Since the gap, which is the application position of the phosphor of the last color, is relatively wide, the phosphor of the last color is sufficiently applied to this gap, and the lack of the colored phosphor does not occur on the phosphor screen.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. In this example, three primary color phosphor stripes R,
This is an example applied to forming a phosphor screen made of G and B and having a width ratio of, for example, 1: 1.6: 1.

In the case of this example, first, the red and blue color phosphor stripes R and B are formed by the steps of printing application of photosensitive phosphor paste → exposure → developing as described above. Finally, a green color phosphor stripe G is formed in the same process.

In this case, when the stripe G is formed, the gap as the formation position of the stripe G is relatively wide. Therefore, when the photosensitive phosphor paste (14) containing the green phosphor is applied by printing as shown in FIG. 1A. As shown in FIG. 1B, the stripe G after the exposure / development is completely filled with the gap, which is the formation position of the stripe G, and is complete.

Therefore, in the case of this example, a chipped portion of the color phosphor stripe does not occur on the phosphor screen.

Although the above-mentioned example is applied to the formation of the phosphor screen composed of the three primary color phosphor stripes R, G and B, the present invention forms the phosphor screen composed of the three primary color phosphor dots. Can be similarly applied to.

〔The invention's effect〕

According to the method of the present invention described above, a phosphor of a color having a large coating area among the phosphors of the three primary colors is finally formed by printing and coating, which is the coating position of the phosphor of the last color. Since the gap is relatively wide, the phosphor of the last color is sufficiently applied to this gap, and the defective portion of the color phosphor is not formed on the phosphor screen, so that a good quality phosphor screen can be formed.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention, FIG. 2 is a sectional view showing a main part of a beam index tube, FIG. 3 is a process chart of forming a phosphor screen, FIGS. 4 and 5 FIG. 3 is a diagram for explaining the present invention. (1) is a face plate, (13) and (14) are photosensitive phosphor pastes, and R, G and B are red, green and blue color phosphor stripes, respectively.

Claims (1)

[Claims] 1. A face plate on which a coating area of at least one of the phosphors of the three primary colors of red, green and blue is larger than a coating area of the phosphors of the other two colors. A method of forming a phosphor screen of a color cathode ray tube, wherein phosphors of three primary colors are sequentially applied by printing to form a phosphor screen, characterized in that a phosphor of a color having a large coating area among the phosphors is applied last. Method for forming phosphor screen of color cathode ray tube.