JP3158345B2 - Method of forming phosphor screen - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is, for example, relates to a fluorescent screen forming method to be applied as a display such as a fluorescent display tube, is <br/> shall particularly related to a method of forming the phosphor screen of the multi-color display .

[0002]

2. Description of the Related Art Conventionally, when fabricating a substrate for a fluorescent display tube, a schematic process is shown in FIG. 5 in which a wiring pattern 2 such as an aluminum thin film is formed on a glass substrate 1 as an insulating substrate (FIG. 5). (A)) Then, an insulating paste is applied by using a screen printing method or a photolithography method to form a paste layer 3 (FIG. 5B). Next, the paste layer 3 is baked at a high temperature of about 560 ° C., and is melted and fixed to the glass substrate 1 to form the insulating layer 3a. Next, a fluorescent screen 5 is formed on the insulating layer 3a through the through hole 4 on the wiring pattern 2 by a printing method, an electrodeposition method, a photolithography method, or the like.
Baking is performed to the extent that the binder is removed, and the substrate manufacturing process is completed (FIG. 5C).

[0003]

The fluorescent display tube is constituted by the above-mentioned substrate, but in recent years, the display has been required to be multi-colored and high-definition. The method had the following problems: (1) The electrodeposition method can form a high-definition pattern, but cannot achieve multicolor. (2) The printing method is easy to be multicolored, but is not suitable for high definition. That is, in the printing method, contact between the patterns on the phosphor screen occurs due to misalignment, bleeding, protrusion, or the like during printing. Since the phosphor is conductive, if there is a contact between the patterns, it causes so-called moire light emission in which light is emitted from a place other than a predetermined part. Therefore, the gap between the patterns is usually required to be 100 μm or more, and it is difficult to achieve high definition of the patterns. (3) In recent years, the photolithography method has been studied and implemented as a method of fine patterning. However, the conventional method is disclosed, for example, in Japanese Patent Application Laid-Open No. Sho 62-14562.
In order to realize multicoloring as disclosed in No. 6, it is necessary to sequentially repeat application, drying, exposure, and development of a photosensitive paste, and the process becomes complicated.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to form a high-definition, multicolor phosphor screen easily and at low cost. An object of the present invention is to provide a method for forming a phosphor screen.

[0005]

In order to achieve the above object, a method of forming a phosphor screen according to the present invention comprises mixing a photosensitive resin and a phosphor on an electrode formed on an insulating substrate. The application and drying of the photosensitive phosphor paste are repeated to form a multicolor phosphor screen, and patterning is performed to form a multicolor fine pattern. Perform patterning
According to a first aspect of the present invention, the photosensitive resin is a negative type photosensitive resin.
Light-sensitive resin, corresponding to the sensitivity of the photosensitive phosphor paste
Exposed individually and then developed to produce multicolor fine patterns
To form The invention of claim 2 corresponds to the type of phosphor.
The photosensitive phosphor paste with the sensitivity of the photosensitive resin adjusted
To form a multicolor fine pattern by one exposure and development
You.

[0006]

FIG. 5 shows the case where the phosphor is formed only by the printing method.
As shown in (c), printing must be performed so that the phosphors 5 do not contact each other. However, in the case of the present invention, since patterning is performed in a subsequent photolithography step, for example, as shown in FIG.
There on the glass substrate 1 formed FIG 4 (b) eg a blue phosphor layer 5b as shown in the no no problem be formed in contact with. Further, as shown in FIG. 4C, when the green phosphor layer 5a is printed and then dried and then the blue phosphor layer 5b is printed, the blue phosphor layers 5b may overlap due to misalignment. Also in this case, since exposure is performed using the photomask 6 as shown in FIG. 4D and patterning is performed as shown in FIG. 4E, a certain degree of positional deviation is allowed. In the case of only the printing method, for example, FIG.
As shown in (c), even if printing is possible without misalignment, the phosphors come into contact with each other due to bleeding during printing, protrusion, or dripping of the paste after printing, resulting in leakage of light. The gap between them must be designed to be about 100 μm or more. However, in the present invention, a fine pattern having a gap between the patterns of about 50 μm can be easily formed even if there is a displacement of about 20 μm which can normally occur during printing. Further, in the present invention, it is possible to simultaneously expose a multicolor pattern by using a photosensitive phosphor paste adjusted sensitivity of the photosensitive resin according to the type of phosphor,
Since a displacement at the time of exposure can be avoided, a fine pattern with higher accuracy can be easily formed.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Example 1) 100 parts of a phosphor is mixed with 100 parts of a cellulosic negative photosensitive resin and kneaded well to prepare a photosensitive phosphor paste. The phosphors include ZnO: Zn as a green phosphor and ZnS: Ag + In as a blue phosphor.
(Zn, Cd) S: Ag + In ₂ O ₃ was used as ₂ O ₃ and a red phosphor (Table 1).

[0009]

[Table 1]

First, as shown in a plan view of FIG. 1A, an aluminum thin film is formed on a glass substrate 1, and a strip-shaped wiring pattern 2 is formed by photolithography.
Next, as shown in FIG. 1B, a paste is formed by photolithography using a photosensitive insulating paste formed by mixing 100 parts of a photosensitive resin with 100 parts of an insulating glass powder on the glass substrate 1. The pattern of the layer 3 and the through holes 4 of the paste layer 3 are formed. The paste layer 3 is baked at about 560 ° C. and melted and fixed on the glass substrate 1 to form an insulating layer 3a. Next, as shown in FIG. 1 (c), the green photosensitive phosphor paste described above is screen-printed on the glass substrate 1 on which the insulating layer 3a and the through hole 4 are formed in a band shape with a width W = about 250 μm. The green phosphor layer 5a is formed by coating. After drying, a blue phosphor layer 5b is formed in the same manner at a pitch of about 250 μm, and after drying, a red phosphor layer 5c is formed. Next, based on the conditions shown in Table 1, only the green phosphor layer 5a on the glass substrate 1 is exposed using a photomask as shown in FIG. Subsequently, the blue phosphor layer 5b
Similarly, only the red phosphor layer 5c is exposed, and the exposing step is completed. Thereafter, three colors are simultaneously developed with pure water to complete the patterning. After drying, the substrate is baked at about 560 ° C. to burn out the resin, thereby completing the substrate manufacturing process. The phosphor pattern obtained here is
The distance d ₁ between the green, blue and red dots is about 50 μm
In fine pattern interval d ₂ between the same color dots are approximately 20 [mu] m (width W ₁ = about 200 [mu] m, the width W ₂ = about 80 [mu] m)
Could be formed.

FIGS. 2A to 2E are sectional views showing the steps of the method for forming the phosphor screen described with reference to FIG. FIG.
In FIG. 1, the formation of the red phosphor layer 5c in FIG. 1 is omitted, but the formation of the phosphor screen is shown by repeating exposure several times in accordance with the sensitivity of each photosensitive phosphor paste in a photolithography process. . That is, as shown in FIG. 2B, the green phosphor layer 5a and the blue phosphor layer 5b applied on the wiring pattern 2 on the glass substrate 1, respectively.
2C, only the green phosphor layer 5a is exposed using the photomask 6a as shown in FIG. 2C, and only the blue phosphor layer 5b is exposed using the photomask 6b as shown in FIG. After exposure, two colors are simultaneously developed to form a multicolor fine pattern.

(Example 2) Since the red phosphor absorbs ultraviolet energy, the sensitivity of the paste is lower than that of green or blue. As shown in Table 1, simultaneous exposure was not possible because of different exposure conditions. Therefore, in this embodiment, a high-sensitivity type cellulose negative photosensitive resin is used as the photosensitive resin mixed with the red phosphor. Hereinafter, the photosensitive resin used in Example 1 is abbreviated as photosensitive resin A, and the photosensitive resin of the high sensitivity type is abbreviated as photosensitive resin B. Table 2 shows the combinations of the phosphor and the photosensitive resin and the exposure conditions.

[0013]

[Table 2]

As can be seen from Table 2, since it is possible to form patterns under the same exposure conditions for all three colors,
In this example, the pattern was formed by one exposure. That is, in the step of forming the phosphor screen shown in cross section in FIG. 3, patterning is performed by simultaneous exposure with the photomask 6 in the photolithography step to form a multicolor fine pattern as shown in FIG. 3C. Therefore, since only one alignment at the time of exposure is required, the accuracy is higher than that of the first embodiment, and the process is easy.

In the above embodiment, a cellulose-based negative photosensitive resin is used as the photosensitive resin. However, the paste is formed by mixing and kneading the photosensitive resin and the phosphor, printing the paste, exposing, developing, and baking the resin. There is no particular limitation on the photosensitive resin as long as it can withstand the removal process,
Other negative photosensitive resins or positive photosensitive resins can also be used.

In the embodiments, the screen printing method is used as the printing method. However, there is no particular limitation as long as the printing method can perform multicolor printing such as the offset printing method or the ink jet method.

(Embodiment 3) By mixing an appropriate amount of an inorganic pigment with a phosphor and using the inorganic pigment as a dispersion type filter, the color of the emitted light can be adjusted. In this example, a blue-green photosensitive phosphor paste was prepared by mixing and kneading 110 parts of a photosensitive resin A with an inorganic powder obtained by adding 10 parts of spinel-based cobalt blue as an inorganic pigment to 100 parts of a green phosphor ZnO: Zn. The same results as in Example 2 were obtained using this blue-green photosensitive phosphor paste instead of the blue paste in Example 2.

In the present invention, a powder having a particle size of about 20
If the particles have a size of μm or more, they remain between the dots without being developed, so that a sharp shape is not formed, which also causes moire emission. Therefore, preferably, the maximum particle size is about 10μ.
In this embodiment, since the phosphor and the inorganic pigment are both classified and used are those having a particle size of about 6 μm or less, particles having a size of about 10 μm or more are not included, and a sharp pattern can be formed. did it.

In the above-described embodiment, the case where the present invention is applied to the method of forming the fluorescent screen of the fluorescent display tube has been described. However, the present invention is not limited to this. Can be applied to the formation of the fluorescent screen. Further, the present invention can also be applied to a case where a pattern is formed only by a pigment without including a fluorescent substance like a color filter of a color liquid crystal display.

[0020]

As described above, according to the present invention,
An extremely excellent effect that a high-definition and multicolor fine pattern can be easily formed at low cost can be obtained.

[Brief description of the drawings]

FIGS. 1A to 1D are plan views illustrating steps of a method for forming a phosphor screen according to an embodiment of the present invention.

2 (a) to 2 (e) are cross-sectional views illustrating steps of an embodiment of a method for forming a phosphor screen according to the present invention.

3 (a) to 3 (d) are cross-sectional views illustrating steps for explaining another embodiment of the method for forming a phosphor screen according to the present invention.

FIGS. 4A to 4E are cross-sectional views illustrating steps of a method of forming a phosphor screen according to the present invention.

5 (a) to 5 (c) are cross-sectional views illustrating steps of a conventional method for forming a phosphor screen.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Wiring pattern 3 Paste layer 3a Insulating layer 4 Through hole 5 Phosphor screen 5a Green phosphor layer 5b Blue phosphor layer 5c Red phosphor layer 6 Photomask 6a Photomask 6b Photomask

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshiyuki Okubo 3-36 Noritake Shinmachi, Nishi-ku, Nagoya City, Aichi Prefecture Noritake Co., Ltd. Inside Mitedo (72) Inventor Tatsuo Matsuyama Noritake Shinmachi 3, Nishi-ku, Nagoya City, Aichi Prefecture No. 1-36, Noritake Co., Ltd. Mitedo Co., Ltd. (72) Inventor Hiroshi Miura 700 Wada, Uenocho, Ise City, Mie Prefecture Inside Ise Electronics Industry Co., Ltd. (72) Inventor Mitsuaki Morikawa Uenocho, Ise City, Mie Prefecture 700 Wada, Ise Electronics Industry Co., Ltd. (56) References JP-A-1-15027 (JP, A) JP-A-1-197937 (JP, A) JP-A-54-16971 (JP, A) JP Sho 61-232530 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 9/227

Claims (2)

(57) [Claims] 1. A method of forming a phosphor screen of at least two colors on a plurality of electrodes formed on an insulating substrate, wherein a negative photosensitive resin and a phosphor are mixed on the electrodes. a photosensitive phosphor paste consisting Te coating, the feeling after drying
Exposure individually according to the sensitivity of the phosphor paste
A method for forming a phosphor screen, wherein an image is formed to form a multicolor fine pattern . A plurality of electrodes formed on an insulating substrate;
For forming at least two colors of phosphor screens
The sensitivity corresponding to the type of phosphor and the phosphor on the electrode
Phosphors made by mixing a photosensitive resin with
After applying the paste, drying and multi-coloring by one exposure and development
Shape of fluorescent screen characterized by forming fine pattern of
Method.