JPS6313231A - Forming of phosphor screen of color cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent exfoliation of picture elements by making a precoat liquid, which is used for a precoat processing prior to the application of phosphor slurry, into the one containing polyvinyl alcohol with Na impurity concentration of less than a specified value. CONSTITUTION:After cleansing the inner surface of a glass panel 21, an aqueous solution containing 0.01-0.1 Weight percent of polyvinyl alcohol with Na concentration of less than 10ppm is applied thereto to form a precoat film 22, Then, a phosphor surface of a color cathode ray tube is structured by arranging, on the precoat film 22, a phosphor slurry film 23 to he dried, exposed and developed so as to form luminous picture elements such as phosphor stripes and so on. And, Na concentration in the precoat liquid is reduced so as to improve bonding with polyvinyl alcohol in the phosphor slurry through hyoxyl radical. Accordingly, bonding strength can be improved and exfoliation of luminous picture elements reduced substantially.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a color cathode ray tube fluorescent lamp that improves the pre-coating process between the cleaning process of cleaning the inner surface of the glass spring y and the wall covering process of the fluorescent slurry. This invention relates to a method of forming a light surface.

[Conventional technology]

Generally, when forming the fluorescent surface of a picture tube, first, the inner surface of the glass spring 1v (21) shown in FIG. (cleaning process).

Next, a very thin aqueous solution of polyvinyl alcohol is sprayed onto the inner surface of the cleaned glass spring /L/ (21) to form a presooto film (22) shown in FIG. 1(b) (precoat step).

Thereafter, a photosensitive binder, such as polyvinyl μA IL'
A phosphor slurry in which a predetermined phosphor is suspended in a solution containing ammonium chromate and M chromate as main components is applied to the inner surface of the glass spring lv (21), and the phosphor slurry is applied to the inner surface of the glass spring lv (21). Ji(2)
3) is formed (slurry application step). This is then dried (drying process), exposed to light through a shadow mask as a color selection electrode by an exposure device to form a latent image (exposure process), and then developed (developing process) to form a latent image at the desired position. A phosphor stripe or phosphor dot (hereinafter referred to as
(collectively referred to as luminescent picture elements).

This process is carried out for three types of phosphor slurry: green (G), # (B), red (R), and three light-emitting pixels are first placed at positions corresponding to the openings of the shadow mask. Diagram (C)
It is formed as shown in .

The flowchart of each of the above steps is shown in FIG.
) to (6). In addition, the slurry film (23)
If there is a defect, the development step (6) is entered without passing through the exposure step (5), the slurry film (23) is removed, and the steps (1) to (6) are completed by +4'. )return.

[Problems to be Solved by the Invention] In the process of forming the above-mentioned three-color light-emitting picture elements, a part of each light-emitting picture element (G), (B), and (R) (5) is usually formed as shown in FIG. 7) is a phenomenon in which the glass panel (21) is not adhered to the glass panel (21), which causes some of the luminescent pixels to be missing, which deteriorates the quality of the fluorescent surface and has a negative impact on the yield of the product.This phenomenon are the above striped light emitting pixels (G), (B), (R)
This tends to become more noticeable as the setting interval of the phosphor and the tab screen pitch P decrease, the coating density of the phosphor increases, and the load on the contact surface Ua of the phosphor increases.

As a countermeasure against such omission of light-emitting pixels, the exposure process (5
), a method of increasing the light-emitting pixel size to a predetermined value, a method of adjusting the strength of development in the developing step (6), and a method of adjusting the intensity of development in the developing step (6),
Methods such as reducing the thickness of the film are being adopted. However, these methods have undesirable drawbacks such as color mixing due to mixing of phosphors and a decrease in light output due to a decrease in the film thickness of the phosphors.

Therefore, conventionally, the formation process (2) of Precor)i (22)
It is known that attempts are made to prevent the omission of light-emitting pixels by improving this. (U.S. Patent No. 4.284.6
No. 94, Japanese Patent Publication No. 57-24616, Japanese Patent Publication No. 59-98
However, in recent years, in order to meet the demand for sharper images, the stripe pitch P has been increased from about 0.6 tm to 0.4 tm.
If the intervals are as small as 0.2 ms or 0.2 ms, the coating density of the fireflies must be reduced.

Therefore, as shown in Figure 3, there is a missing part (8) in the luminescent picture element.
The problem was that the luminance of the light emitted by the light was reduced.

This invention was made to improve the above drawbacks.
It is an object of the present invention to provide a method for forming a fluorescent surface of a color cathode ray tube in which the occurrence of missing light-emitting pixels is extremely small without reducing luminance.

[Means for solving problems]

This invention aims to improve the concentration of sodium (hereinafter referred to as Na
The method is characterized in that a precoat aqueous solution containing 0.01 to 0.1% by weight of polyvinyl alcohol having an impurity of 10 pμm or less is applied to the inner surface of a glass panel and dried.

[Last month]

In this invention, a precoat liquid, which is an aqueous solution of polyvinyl alcohol with a low concentration of Na impurities, is applied to the inner surface of the glass spring μ before the phosphor slurry coating process and dried to form an extremely thin precoat film. Furthermore, it is possible to effectively prevent the omission of light-emitting pixels.

This is because hydroxyl groups based on the polyvinyl alcohol contained in the precoat liquid are deposited on the inner surface of the glass panel before the phosphor slurry is applied, and the fluorescein usually fluoresces through these hydroxyl groups. Na is easily combined with the polyvinyl alcohol contained in the body slurry, but Na is mixed in as an impurity in the polyvinyl alcohol, and the larger the amount of Na mixed in, the more it binds with the polyvinyl alcohol contained in the hydroxyl group. This has a negative effect on the bond between the two.

Therefore, as in the present invention, by reducing the amount of Na mixed as an impurity in the polyvinyl 7μ co-μ of the pre-coating solution, the polyvinyl alcohol in the phosphor slurry can be absorbed through the hydroxyl groups. Improved coupling with This improves the adhesive strength of the phosphor slurry film.

Additionally, it was confirmed through experiments that if the pre-coat film was too thick, the light-emitting picture elements would be missing.

Tsumashi, polyvinyl alcohol/& 0.01~0.1
It was confirmed that by applying and drying a precoat solution containing 10% by weight to the inner surface of a glass spring μ to form an extremely thin precoat film, a fluorescent surface with very few missing single light-emitting pixels could be formed.

Therefore, the appropriate range for the content of polyvinyl alcohol in the precoat liquid is 0.01 to 0.1% by weight a). Below this range, the bond between the precoat film and the phosphor slurry film is weak, and the above-mentioned If it exceeds this range, the precoat film will be too thick and the light-emitting picture element will be missing.

〔Example〕

The present invention will be described in detail below.

Example 1゜To produce a striped light-emitting picture element with a stripe pitch P of 0.2 m, green color with a width of 0.06 tm, 1
Before sequentially forming color and red light-emitting pixels, Na
M total K 23 with an impurity concentration of 0.3 p p m
00 Polyvinyl Lua Co., Ltd.

A glass spring is coated with a pre-coating solution, which is an aqueous solution containing 5% by weight.
It was applied to the inner surface of V (21) and dried.

Thereafter, a phosphor slurry in which a predetermined phosphor is suspended in a solution of a photosensitive binder mainly composed of polyvinyl alcohol and ammonium dichromate is applied to the inner surface of the glass spring N (21) using a conventional method. The phosphor slurry film 1JJi (23) is coated to form a phosphor slurry 1JJi (23) as shown in FIG. A predetermined luminescent picture element was formed. These steps were repeated to sequentially form a fluorescent surface consisting of the luminescent picture elements of the three colors (G), (R), and (B) described above.

The number of missing light emitting pixels on the fluorescent surface of the color cathode ray tube obtained by this method was 0 in green, 1 in blue, and 1 in red.According to the conventional method, 25 pixels were missing in green. Compared to 20 blue spots and 20 red spots, the number has decreased to about 1/2 or less.

Example 2 To manufacture a striped light-emitting picture element with a stripe pitch P of 0.2 m, bO, green color with a width of 06 mm,
Before sequentially forming blue and red light-emitting pixels, N
A pre-coat solution was applied to the inner surface of the glass panel (21) and dried. The pre-coat solution was an aqueous solution containing 1% of polyvinyl alcohol, uo, o1mff with a degree of polymerization of 2500 and an impurity concentration of 1.3 pμm.

Thereafter, when the color cathode ray tube obtained in the same manner as in Example 1 was examined for missing light-emitting pixels on the fluorescent surface, it was found that there were 5 spots in green, 3 spots in blue, and 4 spots in red.

Example 3 In manufacturing a striped light-emitting picture element with a stripe pitch P of 0.2 m, green light with a width of 0.06 am,
Before sequentially forming blue and red light-emitting pixels, for each light-emitting pixel, in the pre-coating step (2) shown in FIG.
Polymerization degree 20 with Na impurity concentration of 9.8 ppm
A glass spring A/(21) was prepared using a pre-coat solution containing 1% by weight of 00 polyvinyl alcohol/l/wo.
It was applied to the inner surface and allowed to dry.

Thereafter, when the fluorescent surface of the color cathode ray tube obtained in the same manner as in Example 1 was examined for missing light-emitting pixels, it was found that there were 5 green pixels, 4 blue pixels, and 4 red pixels.

Figure 4 shows the N content of polyvinyl alcohol in the pre-coating liquid used in the pre-coating process (2) shown in Figure 2.
The relationship between the a impurity concentration and the number of missing light emitting pixels on the fluorescent surface is shown, and it is understood that when the Na impurity concentration is 10 pμm or less, the number of missing light emitting pixels is extremely small.

In addition, when the precoating liquid in the above precoating step (2) is an aqueous solution containing 0.01 to 0.1% by weight of polyvinyl alcohol-μ with a Na impurity concentration of 10 ppm or less, polyvinyl alcohol 7μ Heavy weight% and Na
It has been confirmed that by appropriately selecting a numerical combination of impurity concentrations, it is possible to form a fluorescent surface with extremely few missing light-emitting pixels.

In this case, the degree of penetration of 7 microns of polyvinyl into 1 micron is not so strict, but it is preferably 2,000 to 3,000.

〔Effect of the invention〕

As described above, the present invention includes a cleaning process for cleaning the inner surface of a glass panel.

In the pre-coat process between the phosphor soufflé coating processes, a pre-coat liquid, which is an aqueous solution containing 0.01 to 0.1% by weight of polyvinyl alcohol with a Na impurity concentration of 10 pμm or less, is applied to the inner surface of the glass panel. It is possible to provide a method for forming a fluorescent surface of a color cathode ray tube, which does not reduce the luminance of luminescence and has very few occurrences of missing luminescent pictures.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the main parts to explain the method for forming the fluorescent surface of a color cathode ray tube, Figure 2 is a flowchart to explain the manufacturing process, and Figure 3 is a striped light-emitting picture element. FIG. 4 is a plan view showing a part of the constituent fluorescent surface, and FIG. 4 shows the impurity concentration of polyvinyl urea/l/'':1-lu in the precoating liquid used in the precoating process shown in FIG. 2 and the fluorescent surface. It is a characteristic diagram showing the relationship between the number of missing light-emitting pixels in (1)...Cleaning process, (2)...Precoating process,
(3)...Phosphor slurry film forming process, (4)...Phosphor slurry film drying process, (5)...Exposure process, (6)
...Development process% (21)...Glass spring Jv, (
22) Precoat film, (23) Fluorescent slurry film, G, B, R... Light-emitting picture elements. In addition, in FIG. 1, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A step of cleaning the inner surface of the glass panel, a pre-coating step of applying a pre-coating liquid consisting of an aqueous solution of polyvinyl alcohol to the inner surface of the cleaned glass panel, and a pre-coating step consisting of polyvinyl alcohol and ammonium dichromate as main components. forming a phosphor slurry film by applying a phosphor slurry in which a predetermined phosphor is suspended in a solution of a photosensitive binder to the inner surface of a glass panel; In a method for forming a fluorescent surface of a color cathode ray tube in which a film is dried, and a predetermined light-emitting picture element is formed through an exposure process and a development process, the precoat liquid in the precoat process is a polyester having a sodium impurity concentration of 10 pμm or less. A method for forming a fluorescent surface of a color cathode ray tube, the method comprising using an aqueous solution containing 0.01 to 0.1% by weight of vinyl alcohol.