JPS6232570B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a fluorescent screen for a black matrix type cathode ray tube, and particularly aims at improving the effective light output characteristics of the cathode ray tube.

In order to double the brightness of the fluorescent surface and obtain good contrast, the gaps between the fluorescent dots are filled with graphite (graphite). If the phosphor thus excited emits light in all directions as an isotropic light source, a portion of the emitted light is absorbed by the black matrix placed between each phosphor dot, resulting in attenuation loss. becomes.

If such losses can be reduced,
The light output characteristics of the cathode ray tube will be significantly improved.

In view of the above, the present invention provides a method for directing light emitted from phosphor dots onto a light-absorbing coating such as graphite forming a black matrix deposited on a face plate so that the light emitted from the phosphor dots is directed substantially in front of the face plate. The present invention provides a method for manufacturing a fluorescent screen in which a reflective material is fixed to the screen and the fluorescent dots are separated.

Hereinafter, the details of the present invention will be explained with reference to the drawings showing the steps of the manufacturing method of the present invention.

1 to 3 are partial cross-sectional views of the face plate at each step, in order to show the steps for forming a black matrix on the face plate in the order of steps. A step-by-step explanation will be given below.

I. A face plate 1 made of lead glass or the like forming the screen of a cathode ray tube is chemically cleaned, and a photoresist film 2 is formed on the inner surface by applying photoresist. Next, Shadow Mask 3
After exposing the dried photoresist film 2 to light using a pattern such as the above, it is developed (the arrow u indicates the direction of the ultraviolet light). Fixing part 2r,
2g and 2b are correspondingly R in later steps.
(Fig. 1).

After fixing, a light absorbing material such as graphite (graphite) is uniformly applied to the inner surface of the face plate 1. The thickness of the coating will affect the effectiveness of the black matrix, so it is desirable that it be as thick as possible, but care must be taken to ensure that the photoresist film can be peeled off easily and uniformly in the subsequent process. Figure 2).

After drying the light-absorbing film 4 (graphite coating film), the photoresist is peeled off, and the photoresist film 2 fixed as a temporary pattern is removed.
r, 2g and 2b are dissolved and swollen, and a temporary pattern of photoresist film 2r, is formed by water spraying.
2g and 2b and the light-absorbing film 4 (graphite) applied thereon are removed, and a black matrix is formed with the light-absorbing film 4 (graphite) fixed on the face plate 1 (third step figure).

Next, while referring to FIGS. 4 to 6 showing cross-sectional views of the main parts of the face plate in each step,
The steps of fixing on the light-absorbing coating 4 fixed on the faceplate a substance that substantially reflects the light emitted from the phosphor dots in front of the faceplate will be explained step by step.

In the state shown in FIG. 3, the black matrix adhering surface 14 formed on the face plate 1
(FIG. 4), the photoresist 12 is again applied almost uniformly, and after drying, in order to form an accurate pattern to accurately fix the reflective material on the light-absorbing coating 4, as shown in FIG. In order to use the black matrix itself created in the process leading up to the process as a photoresist photosensitive mask, a slightly stronger amount of ultraviolet light (u' indicates the irradiation direction) is applied to the face plate, taking into account the loss caused by the face plate. The photoresist film is exposed to light from the outside (viewing side) and developed (FIG. 4).

Fixed photoresist films 12r, 12g,
12b and the light-absorbing (graphite) coating 4, a fine powder of magnesium oxide, aluminum, etc. is suspended in an aqueous solution (water glass) of silicon dioxide (SIO ₂ ) as a scattering-reflecting substance and uniformly applied. The stirred solution is uniformly applied and dried (Figure 5). 5 shows a coating of such a reflective material.

The remaining patterns 12r, 12g, 12b... of the photoresist film are removed by a photoresist remover.
The reflective substance coatings 5r', 5g', 5b'... coated thereon are removed by water spray, and the matrix of the light-absorbing coating 4... and the reflective substance coated thereon are removed. Coating 5
Only ... is left (Figure 6).

Next, phosphor substances responsible for each of the R, G, and B emission colors are formed so that phosphor dots are sequentially formed between the black matrix patterns formed in the above steps. Since the process can be carried out using well-known procedures, the explanation will be omitted. Through this process, the phosphors of each color are filled into the circular or striped dots surrounded by the black matrix in a regular manner and slightly larger than the gap between the dots, that is, so as to overlap the light-absorbing layer. Figure 7).

Then, cover the whole thing with a thin film of water glass, etc.
An aluminum vapor deposited film 6 is formed thereon to form a metal back structure.

In the above description, a material having scattering properties was used as an example of the reflective material, but instead of this example, an aluminum vapor deposition film may be formed only on the graphite coating layer. Also,
As an example, we have described a manufacturing process in which the black matrix is first formed and the phosphor dots are formed later, but it can be applied to the reverse case as well, and the same effect can be obtained. It should be obvious.

According to the present invention as described above, the colored light emitted from each phosphor dot is surrounded on the back and sides by the reflective material coating 5 and the aluminum vapor deposited layer 6, so that the amount of attenuated and absorbed light is reduced and the effective light is reduced. Output is greatly improved.

Since the light is irradiated substantially in front of the face plate, the effective light output of the cathode ray tube is greatly improved.

In addition, the effect of the black matrix is not reduced, and there is no risk of deterioration of contrast or smearing, so if it is used in high-brightness type cathode ray tubes such as projection type cathode ray tubes, it can produce clear images with high light output. It is possible to obtain a projected image.

[Brief explanation of the drawing]

The drawings all show the process steps of the manufacturing method of the present invention, and FIGS. 1, 2, and 3 are partial cross-sectional views of the face plate in each step of forming a black matrix, and FIG. , 5 and 6 are partial sectional views of the face plate at each step of forming a reflective material coating on the black matrix, and FIG. 7 is a partial sectional view of the completed screen. 1...Face plate, 4...Light-absorbing coating,
2, 12... Photoresist film, 5... Reflective material coating, 6... Aluminum vapor deposited film.

Claims (1)

[Claims] 1. A photoresist film applied to the inner surface of the face plate, including the light-absorbing coating that partitions the phosphor dots adhered to the inner surface of the face plate, is exposed from the outside of the face plate, and phosphor dots are formed on the developed surface. After depositing a material that substantially reflects light emitted from the face plate in front of the face plate, the photoresist portion hardened by the exposure is peeled off with a photoresist stripper to remove the photoresist only onto the light-absorbing coating. A method for manufacturing a fluorescent screen for a black matrix cathode ray tube that fixes substances.