JPH07240148A - Method for forming fluorescent screen of color picture tube - Google Patents

Abstract

PURPOSE:To provide a method for forming a fluorescent screen of color picture tube in which the roughness of a fluorescent screen can be suppressed, and the peeling of a slurry film pattern can be also suppressed. CONSTITUTION:A phosphor suspension (slurry) containing a polyvinyl alcohol or modified polyvinyl alcohol, a bichromate, phosphor particles and water is applied onto the inner surface of the face plate 4 of the panel part of a color picture tube to form fluorescent screens 5G, 5B, 5R for color picture tube. In this method, the polyvinyl alcohol or modified polyvinyl alcohol used in the phosphor suspension (slurry) is formed of a mixed component of a one having low average polymerization degree and a one having high average polymerization degree, and, preferably, the average polymerization degree ratio of the one having high average polymerization degree to the one having low average polymerization degree is 2.4 times or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a fluorescent film of a color picture tube having a fluorescent film having improved characteristics, and particularly, to suppress unevenness in brightness by suppressing the occurrence of roughness of the fluorescent film as much as possible. The present invention relates to a fluorescent film forming method for a color picture tube which can be reduced.

[0002]

2. Description of the Related Art Generally, the fluorescent film of a shadow mask type color picture tube is formed by the following procedure.

First, a photosensitive first-color phosphor suspension containing polyvinyl alcohol or modified polyvinyl alcohol (water-soluble polyvinyl alcohol derivative), dichromate, green phosphor particles, water and the like. A liquid (slurry) and a second color phosphor suspension (slurry) containing blue phosphor particles instead of the green phosphor particles, and similarly, a red suspension instead of the green phosphor particles. A third color phosphor suspension (slurry) containing phosphor particles is prepared and prepared.

Here, the panel portion of the color picture tube (this panel portion is in a state before the funnel portion and the neck portion are still sealed, and the inner surface of the face plate is exposed by the opening) is rotated. It is mounted on an applicator and a phosphor suspension (slurry) of the first color (green) having photosensitivity is poured onto the inner surface of the face plate to form a slurry coating film of the first color. Then, after drying the slurry coating film of the first color, a shadow mask having a desired pattern is covered thereon, and ultraviolet rays are radiated from the shadow mask for exposure. Due to this exposure, the slurry coating film of the first color is insolubilized only in the portion to be irradiated with ultraviolet rays. Then, the first
Rinse and develop with warm water on the color slurry coating film,
The portion not irradiated with ultraviolet rays is removed by washing with water to form a stripe-shaped or dot-shaped first color slurry coating film pattern formed of the insolubilized portion.

Next, a phosphor suspension (slurry) of the second color (blue) having photosensitivity is poured into the inner surface of the face plate of the panel portion of the color picture tube to form a slurry coating pattern of the first color. A stripe-shaped or dot-shaped second color slurry coating film pattern is formed by the same procedure as that described above. After forming the second color slurry coating pattern, the phosphor suspension (slurry) of the third color (red) having photosensitivity is poured again on the inner surface of the face plate of the panel portion of the color picture tube. The stripe-shaped or dot-shaped third color slurry coating pattern is again formed by the same procedure as that of forming the first-color slurry coating pattern, and the fluorescent film is formed by these three-color slurry coating patterns. It is what is formed.

The formation order of the first color to the third color when forming the three-color slurry coating pattern is not always the same.
The order is not limited to the above, but can be changed arbitrarily.

Then, in order to reduce the roughness (cracks) generated in each slurry coating film when forming the fluorescent film consisting of the above three-color slurry coating pattern,
A fine resin emulsion was added to the phosphor suspension (slurry) of each color, and the resin emulsion was
Moreover, JP-A-55-108412 proposes a means that acts as a lubricant between fluorescent particles having irregular shapes.

[0008]

The means for suppressing the roughness (cracks) of the slurry coating film proposed above has the effect of suppressing the occurrence of the roughness (cracks) occurring in the slurry coating film for some time. In, as the stripe or dot shape on the fluorescent surface becomes finer and finer, the irradiation amount of ultraviolet rays when the slurry coating film is exposed becomes relatively small, and the unirradiated portion is removed by washing with warm water. At this time, there is a problem that the insolubilized portion irradiated with ultraviolet rays is easily peeled off, and a fluorescent surface having a desired pattern cannot be obtained.

On the other hand, in order to prevent the peeling of the insolubilized portion, the thickness of the obtained slurry coating film is adjusted so that the ultraviolet irradiation reaches near the inner surface of the face plate of the panel portion during the exposure of the slurry coating film. Thin, but
If the thickness of the slurry coating film to be applied is reduced, then the slurry coating film will have a lot of roughness (cracks), which causes a problem that the roughness is increased.

The present invention solves these problems all at once, and an object thereof is to suppress the occurrence of roughness of the fluorescent film and to prevent the peeling of the slurry coating film pattern. It is to provide a method for forming a fluorescent film of a tube.

[0011]

To achieve the above object, the present invention provides a phosphor suspension containing polyvinyl alcohol or modified polyvinyl alcohol, dichromate, phosphor particles, water and the like ( Slurry) is applied to the inner surface of the face plate of the panel portion of the color picture tube, in the method for forming a fluorescent film of the color picture tube, polyvinyl alcohol or modified polyvinyl alcohol used in the phosphor suspension (slurry) is at least A means comprising a mixed component having a low average degree of polymerization and a high average degree of polymerization is provided.

In the above means, the mixed component of polyvinyl alcohol or modified polyvinyl alcohol is preferably prepared so that the ratio of the average degree of polymerization of the high average degree of polymerization to the low average degree of polymerization is 2.4 times or more. It

[0013]

[Function] When the slurry coating film applied to the inner surface of the face plate of the panel portion is dried, polyvinyl alcohol or modified polyvinyl alcohol (water-soluble polyvinyl alcohol derivative) is deposited from the aqueous solution to form a coating portion. Since the volume of the film portion is smaller than the volume of the polyvinyl alcohol or modified polyvinyl alcohol contained in (3), cracks are likely to occur in the slurry coating film during the formation of this film. When the slurry coating film is dried, the narrower the distribution of the polymerization degree (molecular weight) of the contained polyvinyl alcohol or modified polyvinyl alcohol, the more the film is formed at the same time. In addition, due to the solubility characteristics of polyvinyl alcohol or modified polyvinyl alcohol, the film formation rate of the slurry coating film is higher in the case of high polymerization degree (high molecular weight) than in the case of low polymerization degree (low molecular weight). The film also becomes hard.

Based on these findings, the above-mentioned means,
Polyvinyl alcohol or modified polyvinyl alcohol having a high average degree of polymerization (high molecular weight) and a low average degree of polymerization (low molecular weight) are mixed and used, whereby the timing of film formation is changed and formed. A film with a low degree of polymerization (low molecular weight), with different film hardness,
A buffering effect is provided between films with a high degree of polymerization (high molecular weight) to form a film with less roughness (cracks) than a film formed with only a high degree of polymerization (high molecular weight). There is.

[0015]

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

FIG. 1 is a sectional view showing the overall construction of an embodiment of a color picture tube in which the fluorescent film forming method according to the present invention is used.

In FIG. 1, 1 is a panel portion, 2 is a funnel portion, 3 is a neck portion, 4 is a face plate, 5 is a fluorescent film, 6 is a shadow mask, 7 is a mask frame, 8 is a deflection yoke, and 9 is An electron gun, 10 is a purity adjusting magnet, 11 is a center beam static convergence adjusting magnet, 12 is a side beam static convergence adjusting magnet, 13 is a magnetic shield, and 14 is an electron beam.

The tubular body which constitutes the color picture tube is
It comprises a panel section 1 arranged on the front side, a neck section 3 accommodating the electron gun 9, and a funnel section 2 arranged between the panel section 1 and the neck section 3. Panel part 1
Has a face plate 4 on the front surface thereof, and a fluorescent film 5 is arranged and formed on the inner surface of the face plate 4. A mask frame 7 is fixedly arranged inside the peripheral portion of the panel portion 1, and the shadow mask 6 is attached by the mask frame 7 so as to be arranged to face the fluorescent film 5. The magnetic shield 1 is provided inside the connecting portion of the panel portion 1 and the funnel portion 2.
3 is provided, and the deflection yoke 8 is provided outside the connection portion of the funnel portion 2 and the neck portion 3. A purity adjusting magnet 10, a center beam static convergence adjusting magnet 11 and a side beam static convergence adjusting magnet 12 are arranged side by side on the outer side of the neck portion 3, and three electron beams 14 (1 (Only a book is shown) is configured to reach the fluorescent film 5 through the shadow mask 6 after being deflected in a predetermined direction by the deflection yoke 8.

In the above construction, the image display operation of the color picture tube shown in this embodiment is the same as the image display operation of the known color picture tube, and such operation is already known. The description of the image display operation of the color picture tube of this embodiment is omitted.

Next, FIG. 2 is a sectional configuration diagram showing the details of the configuration of a very small part of the inner surface of the face plate 4 of the panel portion 1 in the embodiment of FIG.

In FIG. 2, 5G is a green fluorescent film and 5B.
Is a blue fluorescent film, 5R is a red fluorescent film, and other components that are the same as those shown in FIG. 1 are denoted by the same reference numerals.

Then, the face plate 4 of the panel unit 1
The inner surface of the green fluorescent film 5G, the blue fluorescent film 5B, and the red fluorescent film 5 formed in stripes or dots
R is arranged and formed in order. In this case, the arrangement structure for the green fluorescent film 5G, the blue fluorescent film 5B, and the red fluorescent film 5R is already good in a color picture tube. It is known.

In this case, the fluorescent films 5G, 5 of the respective colors are provided.
When forming B and 5R, it is necessary to prepare phosphor suspensions of respective colors containing phosphor particles of respective colors, but an example of the composition of known phosphor suspensions For example, an example of the composition of a green phosphor suspension is as follows. In addition, each composition shows the weight% of solid content.

Green Fluorescent Material (ZnS: Cu · Al) 30.0% Polyvinyl alcohol or modified polyvinyl alcohol 2.5% Acrylic resin (Mitsui Toatsu Almatex E3375) 0.75% Sodium dichromate 0.18 % Surfactant 0.03% Water balance In such a known phosphor suspension composition, the present inventors have found that for polyvinyl alcohol (PVA) or modified polyvinyl alcohol (PVA derivative), the average degree of polymerization (molecular weight) ) Different polyvinyl alcohols (PVA) or modified polyvinyl alcohols (PVA derivatives) are mixed to prepare a plurality of types of fluorescent suspensions, and these fluorescent suspensions are individually separated into panel parts. 1 was applied to the inner surface of the face plate 4 to form a fluorescent film 5. Then, as a result of investigating the degree of occurrence of roughness (cracks) in each of the fluorescent films 5 obtained at this time, the results are shown in Table 1 below. In addition,
As the polyvinyl alcohol (PVA), KPOPLE manufactured by Kuraray Co., Ltd. is used.

[0025]

[Table 1]

In Table 1, polyvinyl alcohol (P
As the type of VA) or modified polyvinyl alcohol (PVA derivative), those described as PVA-205 and PVA-224 are those in which the lower two digits represent the average degree of polymerization, and PVA-205 has an average degree of polymerization of 500 and PVA. -22
4 has an average degree of polymerization of 2,400, and the third digit from the bottom represents the degree of saponification. In addition, polyvinyl alcohol (PV
The reason for using acrolein-modified PVA-224, which has good photocrosslinking property with dichromate by ultraviolet irradiation, in A) or the type of modified polyvinyl alcohol (PVA derivative) is that it has a low polymerization degree. This is to compensate for the decrease in photocrosslinking property with the dichromate due to ultraviolet irradiation. Further, the evaluation of roughness in Table 1 is PVA.
-224 when used alone,
For reference, PVA-205, PVA-210, PV
The case where A-235 is used alone is also mentioned.

As shown in Table 1, PVA-224
(Including acrolein-modified PVA-224) and PVA-
A mixture of 205 and PVA-224 and PVA
-210 mixed with PVA-235
Since the effect of improving the roughness is seen for the mixture of PEG and PVA-205, when two polyvinyl alcohols (PVA) or modified polyvinyl alcohols (PVA derivatives) are mixed and used, they have a low average degree of polymerization. It can be seen that if the ratio of the average degree of polymerization of the high average degree of polymerization is 2.4 times or more, the graininess can be significantly improved.

On the other hand, as shown in Table 1, PVA-2
Among the mixture of 24 and PVA-205, P
If the composition ratio (parts) of VA-205 is more than half, that is, more than 50 parts, the effect of improving the roughness becomes less and moreover the dot shape is deteriorated. It can be seen that the function of improving roughness can be achieved when the composition ratio of the one having a high average degree of polymerization is at least greater than 1.0, preferably 2.0 or more. When the PVA-224 and PVA-205 are mixed and used,
The reason for the deterioration of the dot shape is that PVA-205 has a higher solubility than PVA-224.
It is presumed that if the same washing and removing conditions as those for 100 parts of No. 4 are used, the washing and removing proceeds more than necessary.

Based on these investigation results, an example of the phosphor suspension for each color that can be used for coating and forming the phosphor film in the color picture tube of this embodiment is as follows.

1. Green fluorescent substance suspension Green fluorescent substance (ZnS: Cu.Al) 30.0% Polyvinyl alcohol PVA-235 0.5% Polyvinyl alcohol PVA-224 1.5% Polyvinyl alcohol PVA- 204 0.5% Acrylic resin (Mitsui Toatsu Almatex E3375) 0.75% Sodium dichromate 0.18% Surfactant 0.03% Water balance 2, blue phosphor suspension blue fluorescent Body (ZnS: Ag) 28.0% Crotonaldehyde-modified polyvinyl alcohol (PVA) 224 2.0% Polyvinyl alcohol PVA-205 0.5% Acrylic resin (Mitsui Toatsu Almatex E3375) 1.25% Dichromic acid Sodium 0.20% Surfactant 0.03% Water balance 3, Red phosphor suspension Red phosphor (Y ₂ O ₂ S: Eu) 31.0% Polyvinyl alcohol PVA-224 1.8% Acrolein-modified polyvinyl alcohol PVA-205 0.5% Acrylic resin (Mitsui Toatsu make Almatex E3375) 0.70% Sodium dichromate 0. 18% Surfactant 0.03% Water Remainder Next, as shown in FIG. 2, these three-color fluorescent films 5G, 5 on the inner surface of the face plate 4 of the panel part 1
The coating formation of B and 5R is performed as follows.

However, these three color fluorescent films 5G, 5B,
At the time of forming 5R, as is known, the funnel portion 2 and the neck portion 3 are not sealed to the panel portion 1, and the panel portion 1 exists in an independent state. 4 has an opening that exposes the inner surface.

First, the face plate 4 of the panel unit 1
A three-color phosphor suspension (slurry) for forming a three-color slurry coating film on the inner surface of is prepared. In this case, the prepared phosphor suspension (slurry) is, for example, the green, blue, and red phosphor suspension (slurry) as described above.

Next, the panel portion 1 with the opening facing up.
To a spin coater, and while rotating the panel section 1 at a high speed, any one of green, blue and red phosphor suspensions (slurries), for example, green Of the phosphor suspension (slurry) is poured into the face plate 4 to form a green slurry coating film in which the green phosphor suspension (slurry) is evenly applied on the inner surface of the face plate 4, and thereafter. The green slurry coating is dried.

Next, a shadow mask having a predetermined pattern is placed on the green slurry coating film, and ultraviolet rays from a mercury lamp or the like are radiated from the shadow mask to partially expose the green slurry coating film. . By this irradiation of ultraviolet rays, only the irradiated portion of the green slurry coating film is made insoluble.

Next, the exposed green slurry coating film is washed and developed with warm water, the non-exposed portion of the slurry coating film is dissolved and removed by this washing, and a stripe-shaped or dot-shaped green slurry coating pattern Forming a light film) 5G.

Hereinafter, similar to the case where a stripe-shaped or dot-shaped green slurry coating pattern (fluorescent film) 5G is formed using a fluorescent suspension (slurry) of another color, for example, blue. According to the process, a stripe-shaped or dot-shaped blue slurry coating pattern (fluorescent film) 5B is formed, and then the last color, for example, red fluorescent suspension (slurry) is used to form stripes. Or dot-shaped green or blue slurry coating pattern (fluorescent film) 5
By the same steps as those for forming G and 5B, a stripe-shaped or dot-shaped red slurry coating pattern (fluorescent film) 5R is formed, and the slurry coating pattern (fluorescent film) 5G of each color as a whole is formed. The fluorescent film 5 in which 5B and 5R are alternately provided is formed.

After that, the panel portion 1 on which the fluorescent film 5 is formed
As is well known, aluminum is vapor-deposited on the fluorescent film 5, and after the steps of sealing the funnel portion 2 and the neck portion 3 to the panel portion 1, attaching the electron gun 9 to the inside of the neck portion 3, etc. The color picture tube is completed.

The color picture tube manufactured through the above-described steps has the fluorescent film 5 of each color as compared with the known color picture tube.
Roughness (cracks) generated in G, 5B, and 5R is reduced, and an image with less uneven brightness can be displayed.

The composition of each of the green, blue and red phosphor suspensions (slurries) that can be used in this embodiment, as mentioned in the above description, is the phosphor suspension of each color. Although one example of a suitable composition for a liquid (slurry) is given, each phosphor suspension (slurry) usable in the present invention is not limited to the above-mentioned composition, and a rough ( Obviously, any composition that does not change the function of suppressing cracks can be used instead of the composition.

That is, even when two or more polyvinyl alcohols or modified polyvinyl alcohols are mixed and used, those having a high average polymerization degree and those having a low average polymerization degree,
As long as the ratio of the average polymerization degree of the high average polymerization degree to that of the low average polymerization degree is 2.4 times or more, any mixture may be used, other than polyvinyl alcohol or modified polyvinyl alcohol. The composition may be replaced with another composition as long as it works equivalently, and the composition ratio may be arbitrarily changed unless the function of each composition is changed.

[0041]

As described above, according to the method for forming a fluorescent film of a color picture tube according to the present invention, polyvinyl alcohol or a slurry of a fluorescent substance of each color for coating and forming a fluorescent film is used. Since modified polyvinyl alcohol having a high average degree of polymerization (high molecular weight) and a low average degree of polymerization (low molecular weight) is used as a mixture, it is possible to use a fluorescent film formed on the inner surface of the face plate of the color picture tube. There is an effect that it is possible to display a high-quality image in which unevenness (cracks) is reduced and brightness unevenness is extremely small.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the overall configuration of an embodiment of a color picture tube in which a fluorescent film forming method according to the present invention is used.

FIG. 2 is a cross-sectional configuration diagram showing details of the configuration of a very small portion of the inner surface of the face plate of the panel portion in the embodiment of FIG.

[Explanation of symbols]

1 Panel Part 2 Funnel Part 3 Neck Part 4 Face Plate 5 Fluorescent Film 5G Green Fluorescent Film 5B Blue Fluorescent Film 5R Red Fluorescent Film 6 Shadow Mask 7 Mask Frame 8 Deflection Yoke 9 Electron Gun 10 Purity Adjustment Magnet 11 Center Beam Static Convergence Adjusting Magnet 12 Side Beam Static Convergence Adjusting Magnet 13 Magnetic Shield 14 Electron Beam

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[Procedure amendment]

[Submission date] March 29, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

Meanwhile, in order to prevent peeling of the insolubilized state portion, upon exposure of the slurry coating, so that the irradiation of ultraviolet to near the inner surface of the face plate of the panel unit is reached, the thickness of the slurry coating is obtained, et al. Thin, but
If the thickness of the slurry coating film to be applied is reduced, then the slurry coating film will have a lot of roughness (cracks), which causes a problem that the roughness is increased.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[0025]

[Table 1]

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0030

[Correction method] Change

[Correction content]

1. Green fluorescent substance suspension Green fluorescent substance (ZnS: Cu.Al) 30.0% Polyvinyl alcohol PVA-235 0.5% Polyvinyl alcohol PVA-224 1.5% Polyvinyl alcohol PVA- 204 0.5% Acrylic resin (Mitsui Toatsu Almatex E3375) 0.75% Sodium dichromate 0.18% Surfactant 0.03% Water balance 2, blue phosphor suspension blue fluorescent Body (ZnS: Ag) 28.0% Crotonaldehyde modified polyvinyl alcohol PVA 224 2.0% Polyvinyl alcohol PVA-205 0.5% Acrylic resin (Mitsui Toatsu Almatex E3375) 1.25% Sodium dichromate 0 .20% surfactant 0.03% water balance 3, red phosphor suspension red phosphor (Y ₂ O ₂ : Eu) 31.0% Polyvinyl alcohol PVA-224 1.8% Acrolein-modified polyvinyl alcohol PVA-205 0.5% Acrylic resin (Mitsui Toatsu Almatex E3375) 0.70% Sodium dichromate 0.18% Surfactant 0.03% Water Remainder Next, as shown in FIG. 2, these three color fluorescent films 5G, 5G on the inner surface of the face plate 4 of the panel part 1 are formed.
The coating formation of B and 5R is performed as follows.

Front page continuation (72) Inventor Morishita ▲ Introduction ▼ 1-280 Higashi Koigakubo, Kokubunji, Tokyo Inside Hitachi Central Research Laboratory (72) Yuko Kuroda 3300 Hayano, Mobara-shi, Chiba Hitachi, Ltd. Electronic Device Business Department

Claims (3)

[Claims] 1. A color picture tube fluorescent material in which a phosphor suspension containing polyvinyl alcohol or modified polyvinyl alcohol, dichromate, phosphor particles, water, etc. is applied to the inner surface of the face plate of the color picture tube. In the photo-film forming method, the polyvinyl alcohol or modified polyvinyl alcohol used in the phosphor suspension is characterized by comprising a mixed component of at least a low average polymerization degree and a high average polymerization degree. Method for forming a fluorescent film on a picture tube. 2. The polyvinyl alcohol or modified polyvinyl alcohol mixed component has a ratio of the average degree of polymerization of a low average degree of polymerization to that of a high average degree of polymerization of 2.
4. The method for forming a fluorescent film for a color picture tube according to claim 1, wherein the number is 4 times or more. 3. The modified polyvinyl alcohol comprises at least one selected from crotonaldehyde and acrolein and modified polyvinyl alcohol obtained by heating the polyvinyl alcohol in an aqueous solution. The method for forming a fluorescent film of a color picture tube according to claim 1.