JPS5847815B2 - color - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for manufacturing a black matrix of a fluorescent surface of a color picture tube.

Generally, on the phosphor surface of a color picture tube, a black light-absorbing substance for antireflection is coated between three color phosphor pixels.

This phosphorescent surface is formed by forming a black matrix made of a black light-absorbing material that has many holes on the inner surface of the panel, and then injecting green light into the predetermined positions of the matrix holes (hereinafter referred to as black matrix holes). , blue, and red three-color phosphor dots or phosphor stripes.

To explain one example of this black matrix forming method, as shown in FIG. After forming the photoresist film 2, exposure is performed with light 4 through a shadow mask 3 placed a certain distance from the panel surface, as shown in FIG. 1b.

This exposure is normally carried out three times by changing the position of the light source little by little to correspond to the positions of the three phosphor picture elements of green, blue, and red.

However, in FIG. 1b=e, only two exposures are marked for convenience of explanation.

After the exposed portion 21 of the photoresist film is cured by the above-mentioned exposure, the exposed portion 21 of the photoresist film is peeled off when it is developed with hot water or the like, as shown in FIG. 1C.

Next, a graphite solution consisting mainly of graphite powder mixed with a coating liquid (for example, Aquaduck manufactured by Acheson Company in the United States mixed with water) is applied to the inner surface of the panel and dried, as shown in Figure 1 d. After forming the graphite film 5 as shown in FIG.
The remaining photoresist 21 as a base is swollen, and the swollen photoresist 21 is removed together with the graphite film deposited thereon by hot water spray to form a large number of holes, that is, black matrix holes, as shown in FIG. 1e. A black matrix 7 having 6 is formed.

FIG. 2 is a top view of FIG. 1e, and in this way, the black matrix 7 using graphite as a light absorbing material is formed on the inner surface of the panel 1.

Next, phosphor pixels such as green, blue, and red phosphor dots or phosphor stripes are formed at the corresponding positions of the black matrix holes, and then a filming film is applied to the phosphor. After smoothing the photoreceptor surface to some extent, an aluminum film that becomes a light-reflecting metal film is formed using vacuum deposition or other means, and through processes such as heat treatment, the fluorescent surface of the color picture tube is completed. .

However, in the above process, it is technically very difficult to form a high quality black matrix 7 on the fluorescent surface.

That is, the graphite film of the black matrix 7 has a thickness of approximately 0.
．． Because it is a thin film of 5 to 12 microns, unevenness in the density of graphite (hereinafter referred to as coating unevenness) occurs depending on the method of application and drying method after application. Very often, pinholes occur where graphite is not applied where they should.

If the coating of the graphite film is extremely uneven or if the pinholes are large, the performance of the fluorescent surface of the color receptor quadrant will deteriorate, resulting in a defective product.

FIG. 3 shows a situation in which the shape of the black matrix hole 6 is uneven due to the generation of the pinhole 8, or two black matrix holes 6 are connected.

This kind of defective state that occurs on the black matrix surface is caused by various causes, so it is difficult to take countermeasures against it.
They can reduce the yield of good products in the production process, and in extreme cases, they can occur suddenly and disrupt the mass production process.
Color picture tube production had become a major obstacle.

Therefore, an object of the present invention is to easily obtain a black matrix without the above-mentioned defects, ie, coating unevenness or pinholes, and the details thereof will be explained below.

The uneven coating of the black matrix graphite film or the occurrence of pinholes is thought to be caused by the dispersion button of graphite in the graphite solution, the wetting of the graphite solution with the glass substrate of the panel, or the surface tension of the graphite solution.

As a countermeasure to this problem, we investigated various dispersants or surfactants added to graphite liquid, and found that most of the dispersants or surfactants caused aggregation, but polyoxyethylene sulfate salts (for example, polyoxyethylene Sodium alkyl ether sulfate or sodium polyoxyethylene alkyl phenyl ether sulfate)
Adding a surfactant to the graphite solution improves the dispersion of graphite in the graphite solution, improves the wetting of the graphite solution with the glass substrate of the panel, and prevents uneven coating of the graphite film and pinholes. The measures were found to be very effective.

As a specific example, a graphite solution mixed with the above-mentioned Aquadac in water was used, and a polyoxyethylene sulfate salt-based surfactant, Emar NC (trade name, manufactured by Kao Atlas Co., Ltd.) was added to the above-mentioned graphite solution. When a black matrix is formed by adding 0 to 10 parts to the solid content of the graphite liquid (the remaining content after excluding the content that evaporates when heated at a temperature of 450'Ct), a result as shown in Figure 4 is obtained. Indicated.

In other words, in Fig. 4, the horizontal axis shows the amount of Emar NC added to the graphite solution (Emar NCO relative to the solid content of the graphite solution).
The vertical axis shows the failure rate (relative value) of the black matrix when pinholes with a diameter of 20μ or more are considered defective.
It is known that when the amount of C added is 0.2φ or more, defects due to pinholes are significantly reduced.

1.Although not shown, the Emar NC is approximately 0.2 to 0.
When the concentration of Emal NC was within the range of 6%, good results were obtained with almost no uneven coating, but it was also found that when the amount of Emal NC exceeded about 0.6%, some uneven coating occurred.

From this, when Emar NC is added as a surfactant, the graphite liquid solid content is 0.2 to 0. It was found that a range of 6% is good.

As exemplified above, the present invention has the effect of obtaining a black matrix with extremely low uneven coating and pinholes by using a graphite liquid to which a polyoxyethylene sulfate salt-based surfactant is added. In addition, it has the advantage that this operation can be carried out without being affected by the viscosity, pH, and changes over time of the graphite liquid, so it can be said that this manufacturing method is particularly suitable for mass production.

[Brief explanation of the drawing]

Figure 1 a ``e is an explanatory diagram showing the method of forming a black matrix on a fluorescent surface. Figure 2 is a plan view of the black matrix seen from above than Figure 1 e. Figure 3 shows defects in the black matrix. 1 and 4 are diagrams showing an example of the effects of the manufacturing method of the present invention. 1... Panel, 2... Photoresist film, 3... Shadow mask, 4... Light, 5 ...Graphite film, 6...
Black matrix hole, 7...black matrix, 8...pinhole.

Claims (1)

[Claims] 1. A method for producing a black matrix on the fluorescent surface of a color picture tube, in which a black matrix on the fluorescent surface is formed using a graphite solution to which a polyoxyethylene sulfate salt-based surfactant is added.