JPH01313840A - Formation of fluorescent screen - Google Patents

Abstract

PURPOSE:To obtain uniform panel luminance by forming a photoresist pattern on a transparent substrate in advance and sticking a phosphor-contained slurry liquid to the portion formed with no photoresist pattern. CONSTITUTION:Photoresist resin is fixed on a transparent substrate 1, then it is exposed and developed to form a photoresist pattern 2 with the preset shape, a phosphor-contained slurry liquid is stuck to fluorescent screen forming dot sections 3 surrounded by the photoresist pattern 2. When multi-color fluorescent faces are to be formed, the phosphor-contained slurry liquid 6 is poured by a squeegee 5 via a mask 4 for sticking the phosphor-contained slurry liquid by squeegeeing. The photoresist pattern 2 is peeled off and removed by a peeling liquid, then it is burnt to form a fluorescent screen with the preset shape made of only phosphors 8 on the transparent substrate 1. Precise and uniform panel luminance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a phosphor screen, and particularly to a method for forming a phosphor screen used in plasma displays and the like.

[Conventional technology]

In recent years, plasma displays have been developed as flat displays, and some of them have begun to be put into practical use.

There are two types of color plasma displays: AC drive type and DC drive type.The AC drive type has both X electrodes and Y electrodes formed on the back panel, and a discharge space is provided through a dielectric layer. The drive type has a cathode on the back panel and an anode on the front panel, with a discharge space formed between them. Both have a phosphor layer formed on the front panel.

To form this phosphor layer, the phosphor is dispersed in a photoresist to form a slurry liquid, which is coated on the panel to a uniform thickness, and then exposed and developed using a mask with a predetermined pattern shape. is used.

In particular, in color plasma displays, phosphors of three colors red, blue, and green are painted separately, similar to color cathode ray tubes (CRTs). As a method, CR
A method is known in which a three-color phosphor screen is formed on a flat glass plate using a photo process, which is generally used as a method for forming a phosphor screen.

This method involves coating a panel with a slurry liquid made by dispersing phosphor in photoresist to a uniform thickness, and then exposing and developing it using a mask with a predetermined pattern shape. By repeating each of the three colors green and blue, a fluorescent screen is obtained.

This conventional method is specifically shown in FIG. 11. That is, (a) a transparent substrate 11 is prepared, and (a) a phosphor-containing photosensitive slurry liquid 1 on which a phosphor is dispersed is prepared.
After coating 2 uniformly and drying, (C) exposing and curing using a mask 13 having openings corresponding to the first phosphor (for example, red), and (6) exposing uncured parts to hot water. It is removed by development to form a first phosphor pattern 14. Next, (e) a phosphor-containing photosensitive slurry liquid 15 in which a second phosphor (for example, green color) is dispersed is uniformly applied and dried, and (f) an opening corresponding to the second phosphor is formed. The second phosphor pattern 17 is formed by exposing and curing the uncured portion using a mask 16 with a mask 16, and removing the uncured portion by developing with warm water to form the second phosphor pattern 17.
For example, a photosensitive slurry liquid 18 containing a phosphor in which a phosphor (for example, blue) is dispersed is uniformly applied and dried, and then (i) exposed using a mask 19 having an opening corresponding to the third phosphor and hardened. Then, the uncured portion of the CD is removed by development with hot water to form a third phosphor pattern 20.

[Problem to be solved by the invention]

However, the above conventional technology has the following problems.

(a) A photoresist slurry liquid in which phosphors are dispersed must be uniformly applied onto a glass substrate, and for this purpose, the flow characteristics of the slurry liquid must be optimized. The unevenness in the thickness of the coating film directly appears as unevenness in panel brightness, which becomes a serious problem especially in large panels.

However, it is generally extremely difficult to accurately and uniformly control the thickness of the coating film.

(b) It requires the steps of applying, drying, exposing, developing, and drying a phosphor-containing photosensitive slurry liquid in which phosphor is dispersed;
Particularly when forming a multicolor phosphor screen, it is necessary to repeat the above steps for each color of phosphor. For example, if phosphors of three colors, red, green, and blue, are used, the above steps must be repeated three times. Therefore, the process becomes complicated and takes a long time.

(c) When forming a multicolor phosphor screen, it is necessary to align the photomask corresponding to the arrangement of each color when exposing the phosphor-containing slurry liquid, but in order to form a fine phosphor screen, the High precision is required for the alignment mechanism. However, such highly accurate alignment is difficult in terms of process.

Therefore, there is a drawback that the color reproducibility of the panel is significantly deteriorated due to the positional shift of the phosphor screen, and color mixing is likely to occur.

(d) Furthermore, when forming a multicolor phosphor screen, if the ambient temperature is set high during drying after coating the phosphor-containing photosensitive slurry, so-called thermal fogging will occur, leading to color mixing.
Must be dried in a low temperature atmosphere. As a result, drying takes a long time and productivity decreases.

(e) After coating the entire surface of the glass substrate with a photosensitive slurry containing a phosphor, it is exposed and developed to remove the slurry other than the portion to be left as a phosphor screen;
A large amount of slurry liquid is wasted, and the recovery process and reuse of the slurry liquid after recovery are costly. Additionally, material loss occurs during the recovery stage.

(F) The number of steps is large because it is necessary to perform exposure and development steps after applying the phosphor-containing photosensitive slurry liquid.Especially when forming a multicolor phosphor screen, the above steps are performed for each phosphor, so development is necessary. A large amount of hot water (developing solution) is used in the process, and in the case of reuse, there is a problem that the recovery process and the reuse after recovery are costly.

Therefore, the purpose of the present invention is to
An object of the present invention is to provide a method for easily forming a phosphor screen with high precision, low cost, and high productivity.

[Means to solve the problem]

In view of the above problems, as a result of intensive research, the inventors of the present invention formed a pattern in advance using photoresist on a transparent substrate, and applied a phosphor-containing slurry to the photoresist pattern. For example, they discovered that a fluorescent screen can be easily formed with high precision and efficiency, and came up with the present invention.

That is, in the phosphor screen forming method of the present invention, a photoresist pattern is formed on a transparent substrate in advance, and a phosphor-containing slurry liquid is applied to areas where the photoresist pattern is not formed, thereby forming a phosphor layer. It is characterized by

[For production]

According to the present invention, a photoresist pattern is formed in advance on a transparent substrate, a phosphor-containing slurry liquid is applied to areas where the photoresist pattern is not formed, and a phosphor screen is formed in the required area, Finally, the photoresist pattern is removed, so unlike the case where the slurry is applied uniformly over the entire surface of the transparent substrate, the tolerance range for the flow characteristics of the slurry is extremely wide, and the coating thickness of the slurry can be controlled with precision. Moreover, it is easy to control uniformly, and it becomes possible to obtain uniform panel brightness. This is particularly advantageous in the manufacture of large panels.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 9, taking as an example a case where a phosphor screen in which square dots are arranged in a matrix is formed.

FIG. 1 is a perspective view showing a state in which a photoresist pattern 2 is formed on a transparent substrate 1, and a portion 3 surrounded by the photoresist pattern 2 on the transparent substrate 1 is a phosphor screen forming dot portion. .

FIG. 2 is a longitudinal sectional view of FIG. 1. In the method of the present invention, first, as shown in FIGS. 1 and 2, a predetermined pattern 2 is formed on a transparent substrate 1 using photoresist.

Glass is generally used as the transparent substrate 1 used in plasma displays because it generates less gas and has satisfactory durability.

Various photoresist materials have been considered, but the thickness of the photoresist pattern 2 and the transparent substrate 1
Considering the adhesion with -, solid or liquid photoresist resins used as letterpress or screen printing materials are optimal. In the case of a solid resin plate, there is an advantage that a uniform thickness can be easily obtained. In the case of liquid resin, in order to obtain a uniform thickness, it is necessary to use an appropriate spacer to fix the resin between the transparent substrate 1 and a thin film such as a polyester film, but it is said to be low cost. There are advantages. Furthermore, as will be described later, it can also be used when electrodes are formed on the transparent substrate 1 in advance.

The thickness of the photoresist pattern 2 is suitably 10 to 100 μm, although it depends on the phosphor content of the slurry liquid used.

After the photoresist resin is fixed on the transparent substrate 1 as described above, it is exposed and developed to form a photoresist pattern 2 in a predetermined shape. When a negative photoresist is used as the photoresist resin, it is exposed using a mask having a light transmitting part of a predetermined shape (the one shown in Figs. 1 and 2 is a grid shape), and then the unused material is removed with an appropriate developer. By removing the cured resin, the desired pattern 2 can be obtained.

A phosphor-containing slurry liquid is applied to the phosphor screen forming dot portion 3 surrounded by the photoresist pattern 2 thus formed. Methods for attaching the phosphor-containing slurry liquid to the phosphor screen forming dots 3 include a method in which the slurry liquid is poured into the phosphor screen forming dots 3 by squeezing, or a method in which the slurry liquid is sprayed onto the phosphor screen forming dots 3 by spraying. can be used.

Furthermore, when forming a multicolor phosphor screen such as a full-color plasma display, it is necessary to distribute and deposit slurry liquid containing phosphors of each color to predetermined phosphor screen forming dots 3, respectively. . For example, when forming phosphor screens in three colors of red, green, and blue, red and
Three types of slurry liquid containing phosphors of three colors, green and blue, and three types of masks having openings corresponding to each color are prepared, and the slurry liquid is applied to the phosphor screen forming dot part 3 through the mask.
It is sufficient to repeat the process of adhering to each color three times.

FIG. 3 is a diagram showing an example of attaching a phosphor-containing slurry liquid by squeezing when forming a multicolor phosphor screen. A phosphor-containing slurry liquid 6 is poured into the dot portion 3 using a squeegee 5 through a mask 4 placed on the photoresist pattern 2. In this case, the mask 4 has openings B7 only at positions corresponding to the predetermined phosphor screen forming dots 3, and the predetermined phosphor-containing slurry liquid 6 is poured only into the predetermined phosphor screen forming dots 3. be able to.

In this way, as shown in FIG. 4, the phosphor-containing slurry IJ-liquid can be poured only into the corresponding phosphor screen forming dots.

The above-mentioned process of pouring the phosphor-containing slurry liquid through the mask is repeated using a mask having a predetermined opening for each color of the phosphor-containing slurry liquid, and the predetermined phosphor-containing slurry is poured into each phosphor screen forming dot portion 3. When the slurry liquid 6 is applied and dried, a phosphor screen forming dot portion 3 surrounded by a photoresist pattern 2 on a transparent substrate l is formed as shown in FIG.
A plurality of colors of phosphor-containing slurry liquids 6 can be attached to the phosphor-containing slurry liquid 6.

Next, the photoresist pattern 2 is peeled off and removed using a stripping solution, and then baked at 400 to 450°C for 10 to 60 minutes to form the transparent substrate 1 as shown in FIG.
A phosphor screen of a predetermined shape consisting only of phosphor 8 is formed thereon. Fig. 7 is a plan view of Fig. 6 seen from above;
, R are green, blue, and red phosphors 8 formed on the transparent substrate 1, respectively.

As a phosphor that can be used in the present invention, Y2O is used as a red color.
3: Eu, y, s + Os: Bu, Y3A1s0
+ 2: Eu, Zn, (PO4) 2: 14
n.

YBO3:Bu, (Y, Gd)BO3:εu, GdBO
, :Bu, ScBros:Bu, LuBO, :Eu, etc., and blue colors include Y2SrO, :Ce, CaWO, :P.
b, BaMgA1+sO,3:Eu, etc., and the green color is Zn, Si, :Mn.

BaA1+20+s:Mn, 5rAl+aO+g:Mn
, CaA1120+s:Mn, YBO31Tb, ,,
BaMgA1+402s:Mn, LuBOslTt
l, GdBO3:Tb, 5C80, :Tb, 5r6S
i, O, C1, :Bu, etc.

Further, the phosphor-containing slurry liquid is composed of a binder, a solvent, etc. in addition to the phosphor, and since the binder needs to disappear during firing, it is desirable to use polyvinyl alcohol, for example. If the binder ratio is increased, the edges become less sharp during peeling, so the appropriate ratio of the phosphor to the binder is 1 to 30 parts by weight based on 100 parts by weight of the phosphor. Moreover, water, alcohol, etc. can be used as a solvent.

The concentration of phosphor in the slurry liquid is generally 10 to 60% by weight.
It is.

Furthermore, the stripper used to strip the photoresist layer
As the syneresis, an acid, an alkali aqueous solution, or an organic solvent can be used depending on the type of photoresist. In particular, the stripping liquid is required not to dissolve the binder in the phosphor-containing slurry liquid. For example, when polyvinyl alcohol is used as the binder, it is preferable to use an organic solvent such as methylene chloride as the stripping liquid.

As shown in FIG. 8, an electrode 9 is placed on the transparent substrate 1 in advance.
is formed, by imparting negative photosensitivity to the phosphor-containing slurry liquid, it is possible to easily form a phosphor screen in a desired shape so that the phosphor does not adhere to the electrode 9. can.

In this case as well, first, as shown in FIG. 9, a photoresist pattern 2 having phosphor screen forming dots 3 is formed on a transparent substrate 1 using the method described above, and a photosensitive phosphor-containing slurry liquid is applied to the phosphor screen. The transparent substrate 1 is attached to the forming dot portion 3 before or after the photoresist pattern 2 is peeled off.
Through this, the photosensitive phosphor-containing slurry liquid is exposed and developed. Thereby, the electrode 9 is used as a mask and the phosphor on the electrode 9 is removed, so that the electrode 9 made of only the phosphor 8 and formed on the transparent substrate 1 as shown in FIG. In this way, a phosphor screen with a predetermined shape to which no phosphor is attached can be obtained.

In order to impart negative photosensitivity to the phosphor-containing slurry liquid, for example, when polyvinyl alcohol is used as a binder in the phosphor-containing slurry liquid, 0.5 to 10% by weight based on the polyvinyl alcohol solid content. It is sufficient to add a certain amount of diazonium salt to the slurry liquid.

In the above embodiment, an example in which square dots are arranged in a matrix has been described as the shape of the phosphor screen, but the method for forming a phosphor screen in the present invention is not limited to the shape described above, and can be formed using phosphor screens of various shapes or shapes. It can be applied to forming phosphor screens of various shapes, such as phosphor screens arranged in stripes.

The present invention will be explained in further detail by the following examples.

Example 1 As a photoresist, APRG-42 manufactured by Asahi Kasei Kogyo ■
A matrix-like photoresist pattern with a pitch of 1 mm, a line width of 200 μm, and a thickness of 50 μm was formed on a float glass using the following method. As a phosphor, the average particle size is 5.
p m(7) Using Zn25in<:Mn, polyvinyl alcohol as a binder, and ion-exchanged water as a solvent, the weight ratio of the phosphor and polyvinyl alcohol was i.
A slurry liquid was prepared such that the phosphor concentration in the slurry liquid was 30% by weight.

The slurry liquid was poured into the phosphor screen forming dots by squeezing and dried.

Thereafter, the photoresist was removed by treatment with methylene chloride and baked at 440° C. for 15 minutes to obtain a green phosphor screen arranged in a matrix. The formed phosphor screen had high precision and a thickness of 7 μm.

Example 2 After forming a photoresist pattern on a float glass in the same manner as in Example 1, Zn=S with an average particle size of 5 pm was formed.
iO,:Mn (green), (Y,Gd)BOs:Bu
Three types of slurry liquids containing the respective phosphors of (red) and BaMgA1+a023:Bu (blue) were prepared in the same manner as in Example 1, and three types of slurry liquids were prepared in the same manner as in Example 1.
Using different types of masks, phosphor-containing slurry liquids of each color were poured into predetermined phosphor screen forming dots and dried.

Next, the photoresist was removed by treatment with methylene chloride and baked at 440° C. for 15 minutes to obtain a three-color phosphor screen arranged as shown in FIG. The formed phosphor screen had high precision and a thickness of 7 μm.

Example 3 To the three types of phosphor-containing slurry liquid of Example 2,
A photosensitive phosphor-containing slurry liquid was prepared by mixing 5% by weight of diazonium salt with respect to polyvinyl alcohol. On the other hand, as a transparent substrate, a glass plate with parallel electrodes formed on the surface as shown in FIG. 8 is used, and a photoresist pattern is formed on the surface as shown in FIG.
In the same manner as in Example 2, three types of phosphor-containing slurry liquids were poured into the dot portions of the phosphor screen and dried.

Next, the photoresist pattern was peeled off in the same manner as in Example 2, and then the transparent substrate was exposed to light from the back side and further developed to remove the phosphor on the electrodes. after that,
It was baked at 440° C. for 15 minutes to obtain a three-color phosphor screen arranged as shown in FIG. The formed phosphor screen had high precision and a thickness of 7 μm.

〔Effect of the invention〕

According to the method of the present invention, unlike the conventional method of applying a slurry liquid to the entire surface of a transparent substrate, the permissible range of the flow characteristics of the phosphor-containing slurry liquid is significantly wider, and the coating thickness of the slurry liquid can be accurately and uniformly applied. It is easy to control and it is possible to obtain uniform panel brightness.

In addition, when forming a multicolor phosphor screen, we compared the conventional method of using a phosphor-containing photosensitive slurry liquid and repeating exposure and development through a photomask for each color of phosphor-containing photosensitive slurry liquid. Therefore, the process of the present invention is simple and the manufacturing time can be significantly shortened. Furthermore, since the phosphor-containing slurry liquid is applied only to the phosphor screen formation area of each color, there is no part of the phosphor-containing slurry liquid that is removed, and it is used almost as it is to form the phosphor screen, resulting in wasted slurry liquid. becomes less. Moreover, the amount of developer used for the phosphor-containing photosensitive slurry can be significantly reduced.

Furthermore, there is no misalignment of the phosphor screen caused by misalignment of the photomask during 19M light, making it possible to create a panel with excellent color reproducibility and no color mixture.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a state in which a photoresist pattern is formed on a transparent substrate in the method of the present invention, Fig. 2 is a vertical cross-sectional view thereof, and Fig. 3 explains the method of depositing a phosphor-containing slurry liquid. Figures 4 and 5 are vertical cross-sectional views showing the state in which the slurry liquid is fixed to the phosphor screen forming dots surrounded by the photoresist pattern on the transparent substrate, and Figure 6 is a vertical cross-sectional view of the photoresist pattern. 7 is a plan view of FIG. 6, FIG. 8 is a plan view of an example in which electrodes are formed on a transparent substrate, and FIG. 9 is a plan view of the state of the phosphor screen after pattern removal. FIG. 10 is a plan view showing a state in which a photoresist pattern is formed on a transparent substrate shown in FIG. The figure is a process diagram showing a conventional method for forming a multicolor phosphor screen. ■, 11...Transparent substrate 2...Photoresist pattern 3...
...Phosphor screen forming dot part 4.13.16.19...
Mask 5... Squeegee 6... Phosphor-containing slurry liquid 7...
...Mask opening 8 ..... Phosphor 9 ..... Electrode

Claims (7)

[Claims] (1) In a method of forming a phosphor screen on a transparent substrate, a pattern is formed in advance using a photoresist on the transparent substrate, and a phosphor-containing slurry liquid is applied to the areas where the photoresist pattern is not formed. , a phosphor screen forming method characterized by forming a phosphor layer. (2) The method for forming a phosphor screen according to claim 1, wherein a negative photoresist is used as the photoresist. (3) The method for forming a phosphor screen according to claim 1, wherein the phosphor-containing slurry liquid contains polyvinyl alcohol. (4) In the phosphor screen forming method according to claim 1, phosphor-containing slurry liquids of multiple colors are used, and the phosphor-containing slurry liquids of each color are selectively poured in correspondence to the arrangement of the phosphor screen of each color. A method characterized by: (5) The method for forming a phosphor screen according to claim 4, characterized in that a mask or screen plate having openings corresponding to the arrangement of the phosphor screens of each color is used. (6) In the phosphor screen forming method according to any one of claims 1 to 5, after depositing the phosphor-containing slurry liquid,
A method characterized by peeling off and removing the photoresist pattern using a stripping solution. (7) In the method for forming a phosphor screen according to any one of claims 1 to 6, the phosphor-containing slurry liquid contains a photoresist so as to have photosensitivity, and after the slurry liquid is attached, exposure is performed. , a method characterized by removing unnecessary phosphor layers by developing.