JPS61237333A - Formation of fluorescent screen of color picture tube - Google Patents

Abstract

PURPOSE:To form a fluorescent film which shows less fluctuation in the size of width and shows least mixture of color and obtain a high quality flat type color picture tube by forming the fluorescent film through covering a metal film formed at the internal surface of back plate with organic pigment. CONSTITUTION:A metal film 2 is formed at the internal surface of a back plate 1 through vacuum deposition of aluminum, the metal film 2 is processed with aqueous solution of organic pigment eosin Y and is then dried, and thereafter the surface is coated with aqueous solution of photosensitive resin and it is then dried to form a photosensitive resin. Next, zinc chloride is formed at the exposing area of photosensitive resin film by exposing the area which is to be coated with a first index fluorescent material with the light of ultra-high pressure mercury lamp a from the internal side of back plate 1 through the photo mask having the striped light transmitting part. Next, after applying (Y, Gd) AlO3:Ce powder as the first index fluorescent material to the photosensitive resin film, extra powder is eliminated by the air spray. Thereby, the fluorescent material is applied only to the exposed area. In succession, the processing of exposure-application of fluoresent material powder-air spray is repeated sequentially and thereby the striped fluoresent material film can be formed.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a color picture tube, in particular, a fluorescent surface is formed on the inner surface of a pack plate constituting one main surface of a flat pulp, and an image obtained there is The present invention relates to a method for forming a fluorescent surface of a flat color picture tube that is viewed from the outer surface of the face plate.

[Background of the invention]

Conventionally, a flat color picture tube has been proposed in which the electron gun of the picture tube is arranged parallel or almost parallel to the face plate in order to reduce the thickness of the picture tube (Utility Model Application No. 59-72653).
issue). This uses a beam index system, and the image is viewed from the face plate side opposite to the back plate, which is provided with the three primary color phosphor films and the index phosphor film.

That is, a metal film is formed on the inner surface of the back plate, which functions to reflect light and accelerate electron beams, and on the metal film, three primary color phosphor stripes of red, green, and blue are repeatedly arranged. Index phosphor stripes for detecting the position of the scanning beam are repeatedly arranged in regular association with the three color phosphor stripes to form a phosphor surface.

Such a fluorescent surface has conventionally been produced using the slurry method, which is well known as a method for forming the fluorescent surface of ordinary color picture tubes.
Alternatively, it can be formed by photo-tackiness using a photosensitive agent that develops tackiness upon exposure to light and a powdered phosphor.

However, in a normal color picture tube, a phosphor film is formed on the glass surface that makes up the face plate, whereas in the above-mentioned flat color picture tube, the phosphor film is formed on a metal film. Ru.

Therefore, during exposure to form each phosphor stripe, the exposure light that has passed through the photomask is reflected multiple times between the metal film and the photomask, resulting in non-exposed areas in the photosensitive coating film. This tends to cause problems such as uneven phosphor stripe widths, color mixing, and blockage, such as green phosphor penetrating into blue phosphor areas.

[Purpose of the invention]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for forming a color picture tube phosphor surface in which the problems of non-uniformity of the width of each phosphor film and color mixture are improved.

[Summary of the invention]

For this purpose, the present invention is to coat the metal film with the organic dye by treating the metal film with a dye solution containing the organic dye after forming the metal film.

Ultraviolet light is generally used as the exposure light, but in this case, the organic dye described above must also have light absorption properties for ultraviolet light, such as eosin Y.
(C2oH605Br4N&2), Congo Red (C
8z"22N6N"206S2) or black dye can be used.

In other words, by coating with such an organic dye, the exposure light that passes through the photomask is absorbed by the dye.
Reflection from the metal film is reduced and multiple reflections between the metal film and the photomask are eliminated.

[Embodiments of the invention]

The figure is a sectional view of the pulp of a flat color picture tube showing an embodiment of the present invention. In the figure, 1 is a bank plate, 2 is a metal film made of aluminum, and a blue phosphor stripe 3B and a red phosphor stripe 3B are disposed on the metal film.
R1 A first index stripe 311 and a green phosphor stripe 3GI, which is a mixture of a second index phosphor and are formed in the middle of these and almost in one layer, are regularly and repeatedly arranged. There is.

On the other hand, 4 is a back plate facing parallel to back plate 1, and 5 is an inner surface of a face plate for curving the electron beam emitted from the electron gun housed in the pulp neck in the direction of the fluorescent surface, although it is omitted in the figure. The viewer sees an image on the phosphor surface through the face plate 4 and the transparent electrode 5 as shown by arrow A.

Next, a method for forming a fluorescent surface according to this embodiment will be explained.

A metal film 2 is formed by vacuum-depositing aluminum on the inner surface of the back plate 1. Next, this metal film 2 was treated with a 0.5 wt % aqueous solution of organic dye eosin Y and dried, and then an aqueous solution of a photosensitive resin having the following composition was applied and dried to form a photosensitive resin film. Form.

Alginate propylene glycol ester...
0,6 vr tP-N-N dimethylaminobenzenediazonium zinc chloride...3wt% Pluronic L-9
2 (Product name, Wyandott@, USA) (Oxy7ethylene oxypropylene block copolymer) CM) 03wt% pure water
・・・・・・Remaining part Next, light from an ultra-high-pressure mercury lamp is applied to the inner surface of the bank plate 1 through a photomask having a striped light-transmitting part.
Expose the area to which the index phosphor is to be applied.

As a result, the exposed portion of the photosensitive resin film decomposes the diazonium salt to produce zinc chloride, which absorbs moisture in the air and becomes sticky. Therefore, after applying (Y,Gd)MCB:C@ powder as the first index phosphor onto the photosensitive resin film and removing the excess powder with air spray, the exposed area The phosphor is attached only to the phosphor.

Subsequently, the blue phosphor ZnS:Ag was subjected to the exposure-phosphor powder application-air spray process as described above.

Green-emitting second index phosphor YBAt601
2-Ce mixed green phosphor ZnS:Cu, A/\
The same procedure was repeated for red phosphors Y and 028:Eu to form striped phosphor films, and then heated at 430°C.
Baking is performed for 2 hours to incinerate and remove organic matter.

After that, the fluorescent surface was formed in this way) (the face plate 1 and the face plate 4 covered with the transparent conductive film 5 of tin oxide, and the neck part (not shown in the figure) were heated at 450° C. and A flat color picture tube was obtained by baking for several hours, welding, and then enclosing an electron gun.

The fluorescent film thus formed had no non-uniformity in stripe width and was good with little color mixture. Also,
Since the organic dye itself is thermally decomposed and removed in the paking step after forming the fluorescent film, it does not cause a decrease in the reflectance of the metal film and the brightness of the picture tube.

The case where the phosphor film is formed by the photoadhesion method has been described above, but it goes without saying that the phosphor film may also be formed by the so-called slurry method. That is, a phosphor slurry made by mixing phosphor particles in a photosensitive binder of polyvinyl alcohol and dichromate is poured onto the inner surface of the bank plate 1 on which the metal film 2 has been formed, and is coated uniformly by spinning. One layer of slurry is made, then heated and dried, and then exposed to ultraviolet light through a photomask.
Next, a development process is performed to wash away the unexposed areas and form a phosphor stripe. These steps are repeated for each of the three-color phosphor and the index phosphor to form a phosphor surface, which is then treated with the aqueous solution and then baked to remove organic matter by ashing.

However, the structure of the phosphor film itself is not limited to the arrangement as in the above embodiment, and the present invention can also be applied to a phosphor surface using a phosphor film having any other arrangement. The same applies.

In the above-mentioned embodiment, an example was explained in which the bank plate and the face plate were arranged in parallel to face each other. However, the present invention is not limited to this, and the present invention is not limited to this. The back plate and the face plate do not necessarily have to be parallel as long as they are viewed from the face plate side.

〔Effect of the invention〕

As explained above, according to the present invention, after coating the metal film formed on the inner surface of the bank plate with an organic dye,
By forming the phosphor film, it is possible to form a phosphor film with no variation in width dimension and less color mixture, and a flat color picture tube of excellent quality can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS The figure is a sectional view showing an embodiment of the present invention. 1... Back plate, 2... Metal film, 3B,
3GI2, 311, 3R... phosphor stripe,
4...Face plate, 5...Transparent conductive film.

Claims (1)

[Claims] A step of forming a metal film on the inner surface of the back plate that constitutes one main surface of the flat bulb, a step of coating this metal film with an organic dye, and a step of forming a phosphor film on the coated metal film. A method for forming a fluorescent surface of a color picture tube, the method comprising at least the steps of: