JPS624812B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved screen printing method for relatively easily forming a three-color stripe pattern phosphor film for a color cathode ray tube.

Currently, the fluorescent film of color cathode ray tube panels is
It is formed by an exposure method using a PVA-based slurry containing ammonium dichromate, but if it becomes possible to form it by a printing method, it is expected to significantly reduce costs. Development of three-color pattern formation technology using various printing methods is progressing both domestically and internationally. The surface on which the fluorescent film is formed on current color cathode ray tube panels is a spherical inner surface, and the surface tolerance is about ±0.3 mm.It is difficult to apply printing technology as it is. If the surface tolerance is small, it becomes possible to form a three-color stripe pattern by screen printing.

For example, when forming a three-color pattern on a flat panel using the screen printing method, the first color can be printed without much problem, but when printing the second and third colors, the printing pattern of the first color or the first and second colors can be printed. Because of the presence of the squeegee, the screen plate and the printing surface do not come into close contact with each other, and as a result, the ink sag and sag becomes large, causing the predetermined pattern width and protruding into adjacent patterns of other colors, causing color mixing. Become. Of course, if you consider various conditions such as the flow characteristics of each color ink, squeegee printing pressure, screen gap, squeegee speed, etc. and select these appropriately, it is possible to match the pattern width and film thickness of the three colors to approximately the specified values. . However, the conditions for this are that the second and third color printing inks must have fairly high viscosity, and in order to improve plate separation during printing, it is necessary to apply large tension to the frame of the screen plate, or to apply large tension to the screen plate frame. Various problems arise in terms of printing accuracy and the printing durability of the screen plate, such as a large printing press. Formation of a fluorescent film for color cathode ray tubes by a printing method has been desired for some time, but it has not yet been put into practical use for the reasons mentioned above.

An object of the present invention is to eliminate the drawbacks of the prior art and to provide a method for relatively easily forming R, G, and B three-color stripe patterns with uniform pattern width and film thickness using an improved screen printing method. be.

To be more specific, a black matrix pattern with a thickness larger than that currently formed by exposure methods is printed and formed in advance at a predetermined black matrix (BM) formation position on the printing surface with high precision.
To provide a means for creating a so-called black matrix and dam, and to sequentially print and fill each color phosphor ink of R, G, and B by aligning each color phosphor pattern forming position of the dam. Therefore, it is an object of the present invention to provide a means for relatively easily forming a three-color fluorescent film surface with uniform pattern width and film thickness.

In the present invention, by screen printing method,
The following method was invented to form a three-color pattern phosphor film in which the pattern width and film thickness of each color are uniform to predetermined values.

First, a stripe pattern with a pattern width equivalent to or less than the predetermined black matrix width and a film thickness equivalent to or greater than the predetermined optimal thickness of the fluorescent film is formed on the black matrix forming area on the surface of the panel to be printed. Print and form with high precision.

Next, after drying and curing it, for the "dam" shaped part formed between the stripe patterns,
Fluorescent material printing is carried out, and in that case, R.
G and B color phosphor inks can be patterned in predetermined "dam" shaped portions for each of R, G, and B colors so that the film thickness after drying does not exceed the height of the "dam". Align and print sequentially,
Due to the regulating effect of the "dam", the pattern width and film thickness are uniform, and high-definition 3 with no color mixing into adjacent patterns.
Color fluorescent films can be formed relatively easily.

Here, the "dam" forming pattern is for controlling the subsequent phosphor printing, and may be formed by printing on a black matrix pattern previously formed by an exposure method, and is heated at approximately 433° C. in the post-process. It may also be one that volatilizes during firing. In some cases, if the "dam" also serves as a black matrix, the ink for printing the "dam" may be, for example, an ink containing fine graphite powder for black matrices, which is conventionally used. You can achieve your goals by using and printing with high precision.

Furthermore, the dry and cured film of the "dam" forming pattern must have a property that it will not be attacked by the solvent of the phosphor ink to be printed next. If printing is done using ink of the same type as the phosphor ink, the ``dam'' will be partially dissolved or deformed by the solvent during phosphor printing, and the regulating effect of the ``dam'' will be impaired. It turns out. In this regard, oxidative polymerization type inks and solvent-free thermosetting inks based on rosin-modified maleic acid have a film that after drying and curing is resistant to the solvents used in phosphor printing inks. It is suitable as an ink for forming a dam according to the present invention.

Next, embodiments of thick black matrix pattern formation and three-color pattern formation according to the present invention will be described and explained. First, using a combination of a stripe pattern photomask and a mesh pattern photomask with predetermined specifications, the pattern opening width is 40 to 45μ, and the pitch is
A screen plate for forming a "dam" print having a 140 μm print area pattern is created. This creation method is
This is a method for creating a so-called metal mask, which consists of exposure from both sides using the two types of photomasks, development, nickel plating, resist peeling, etching, and reinforced nickel plating, and this method has already been developed by the applicant and a patent application has been filed. It is. In addition, the printing ink for forming a "dam" that also serves as a black matrix includes 45 parts (by weight) of rosin-modified maleic acid, 25 parts (by weight) of rosin, and 10 parts (by weight) of titanium white.
1500 parts (by weight) for 100 parts (by weight) containing 30 parts (by weight) of butyl cellosolve as a solvent.
15 parts (by weight) of Metsuyu's fine graphite powder and 0.5 parts (by weight) of fine quartz powder (trade name Aerosil)
The viscosity was approximately 2500 poise at a room temperature of 23°C and a shear rate of 10/sec. Using this printing ink for black matrices and the above-mentioned screen plate, a flat glass panel is coated with the specified amount under the conditions of a squeegee drop (printing pressure) of approximately 250 μm, a screen gap of approximately 600 μm, and a squeegee speed of 30 mm/sec. Align and print so that a pattern format can be created at the position. After heating and drying, the obtained black matrix layer, like the black matrix layer 2' in FIG. 2, is different from the black matrix layer 2 in FIG. 1, which is conventionally formed by exposure. It's thick enough,
The film thickness is 10 to 12 μm, the pattern width is 50 to 70 μm, and the pattern pitch is 140 μm. Of course, when forming a black matrix pattern, the pattern dimensional accuracy and printing position accuracy are important issues, but these can be kept within tolerances by improving and developing screen plates and printing machines.

In addition, in the diagram showing the state of black matrix layer formation in FIG. 1, 1 indicates a panel substrate, and 2
is a black matrix layer formed on the panel substrate 1. Also, in Figure 2a, 2'
3 indicates a thick black matrix layer, and 3 indicates a dam-shaped portion.

Next, the black matrix layer 2' of FIG.
A method of performing phosphor printing on the dam-shaped portion 3 consisting of the following will be explained with reference to FIG. 2b. In this case, as a printing screen plate, the pattern opening width is
It has an image area of 50 .mu.m and a pattern pitch of 420 .mu.m, and is a so-called metal mask made using two types of photomasks with predetermined specifications, a stripe pattern and a mesh pattern, similar to the screen plate for forming the black matrix described above. As a phosphor printing ink, an average particle size of about 6 μm is used for 10 parts (by weight) of a vehicle consisting of 1 part (by weight) of ethyl cellulose and 9 parts (by weight) of α-terpineol.
20 parts (by weight) of phosphor is mixed and kneaded, and its viscosity is approximately 1000 at 23℃ and shear rate of 10/sec.
Poise, and has almost the same flow characteristics for the three colors R, G, and B.

Using the above-mentioned phosphor printing screen plate and phosphor ink, the squeegee drop (printing pressure) is approximately
250 μm, a screen gap of about 500 μm, and a squeegee speed of 30 mm/sec, the first color printing 4 of FIG. 2 b is applied to the dam-shaped portion 3 of FIG. Positioning, printing, and drying are performed three times in the order of second color printing 5 and third color printing 6 (B, G, R) to form a three-color stripe pattern. For each color, the film thickness immediately after printing rises slightly higher than the dam height, but as the solvent evaporates due to drying, the apparent height becomes approximately 11μ, which is almost the same height as the dam, and the dam control effect in printing the next color. It is possible to obtain a striped pattern fluorescent film with uniform pattern width and film thickness for all three colors without loss. In addition, the thick black matrix (dam) is formed using an oxidative polymerization type ink, and its dry film is resistant to solvents, such as solvents of phosphor printing ink (α terpineol is mixed with butyl cellosolve, butyl carbitol acetate, etc.). ), the "dam" will not melt and deform. As long as there are no defects or large variations in thickness in the "dam", printing ink will not flow into adjacent pattern areas of other colors, making it possible to form a high-definition three-color pattern without color mixing.

The black matrix (dam) forming ink according to the present invention contains 29 parts of melamine formaldehyde resin, 26 parts of trimethylolpropane maleate, 26 parts of trimethylolpropane fumarate,
Blown linseed oil 2 parts, P-toluene sulfonate
We tried a so-called solvent-free, human-set type ink containing 1.5 parts of graphite powder and 10 parts of fine graphite powder. As a result, a black matrix (dam) with a thickness of about 15 to 18 μm thicker than that obtained using the oxidative polymerization type ink was obtained, and a phosphor with an average particle size of 8 to 10 μm was used for the dam, but R・Print G and B color phosphor inks in the same manner as above,
A high-definition three-color stripe pattern without color mixing could be formed.

In this way, the panel on which the three-color fluorescent film pattern has been formed is subjected to the usual post-processing consisting of filming, aluminum vapor deposition, and baking at 420°C in the same way as panels made by conventional exposure methods, and the pattern is formed. As a result of evaluation as a real ball in combination with a compatible shadow mask, which is the source of the present invention, a practical color cathode ray tube without color mixture was obtained as long as the black matrix (dam) pattern according to the present invention was not absent.

As is clear from the above-mentioned embodiments, according to the present invention, it is possible to form a black matrix layer that is much thicker than that obtained by conventional exposure methods. Due to the "Dam" regulation effect, the pattern width can be changed relatively easily even with phosphor ink having almost the same flow characteristics for R, G, and B colors and under the same printing conditions.
It has become possible to form a high-definition three-color fluorescent film with uniform thickness and no color mixture. Therefore, the manufacturing cost can be significantly reduced compared to the conventional exposure method. In addition, since the phosphor printing ink in this case requires low viscosity for all three colors, there is no problem with plate separation during printing, and the screen gap can be less than a few hundred micrometers, making it possible to use normal multicolor screens. Compared to printing methods, this method has a great advantage in terms of the printing life of the screen plate.

Note that the present invention is not limited to color cathode ray tube panels, but can be widely applied to other display panels and multicolor pattern formation.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing the state of formation of the black matrix layer of a conventional color cathode ray tube panel, Fig. 2 is a side sectional view of a color cathode ray tube panel prepared according to the present invention, and Fig. FIG. 2b shows a state in which a thick black matrix layer according to the invention is printed and formed, and phosphor layers of three colors R, G, and B are sequentially printed and formed on the thick black matrix layer forming panel. It is a diagram. 1... Panel, 2'... Thick black matrix layer, 3... Dam, 4, 5, 6... R.G.
B color phosphor layer.

Claims (1)

[Scope of Claims] 1. A method for forming a three-color stripe pattern phosphor film of R, G, and B by screen printing on a color cathode ray tube panel having a flat or cylindrical inner surface to be printed, comprising: At the predetermined black matrix layer formation position, use an ink whose dry and cured film is not eroded by the solvent of the phosphor ink that will be printed later, and the pattern width is equal to or equal to the width of the predetermined black matrix layer. A stripe pattern is printed in advance and the film thickness is equivalent to or greater than a predetermined fluorescent film thickness,
After drying and hardening, a solvent that does not dissolve or damage the "dam" forming material is applied to the "dam" shaped part formed by the stripe pattern at a temperature of about 23°C and a shear rate of 10. R, G, and B color phosphor inks formulated to have a viscosity of 4000 poise or less, usually around 1000 poise at /sec, are printed so that the film thickness after drying is equivalent to or less than the height of the dam, and , R, G, and B color patterns are aligned and printed one after another so that they are formed in the "dam" shaped portions at predetermined positions.
A method for forming a color cathode ray tube fluorescent film, characterized by forming a three-color fluorescent film pattern. 2. The printing ink used to create the "dam" pattern that is preformed at the black matrix formation position is an oxidative polymerization type or a solvent-free heat set type, and the dry and cured film acts as a solvent for the phosphor ink to be printed next. A color cathode ray tube according to claim 1, characterized in that an ink that is resistant to organic solvents such as diluents is used to form a "dam" for printing a three-color fluorescent film pattern. How to form a light film. 3. If the dam formation pattern is to be used as a black matrix, the printing ink for the pattern may be one having the properties set forth in claim 2 above, and a graphite fine powder for the black matrix or fine graphite powder for the black matrix. A color cathode ray tube fluorescent film according to claim 1 or 2, characterized in that a black matrix layer forming ink containing a light-absorbing color substance that does not dissipate when fired at about 430° C. is used. How to form.