JP2002060746A - Pigment-bearing phosphor and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To Provide a pigment-bearing phosphor slight in pigment coming off, uniform in pigment adherence thereto, slight in overcoating in forming a coating film and excellent in coating characteristics, and to provide a method for producing the above phosphor. SOLUTION: This pigment-bearing phosphor is characterized by bearing a pigment via a 2nd coating film comprising a mixture of gelatin and gum arabic on a 1st coating film comprising a mixture of gelatin and gum arabic and formed on the surface of phosphor particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor with a pigment whose surface is coated with pigment particles and a method for producing the same. More specifically, the present invention relates to a pigmented phosphor to which a pigment is adhered by using a mixture of gelatin and gum arabic, the surface of which is modified, and which has excellent coatability and a method for producing the same.

[0002]

2. Description of the Related Art As a blue phosphor and a red phosphor applied to a phosphor screen of a cathode ray tube for a color TV, a phosphor with a pigment in which the surface of each phosphor particle is coated with a blue pigment particle and a red pigment particle is used. It is used. When a phosphor with pigment is used for the phosphor screen, a part of the emission of each phosphor is cut and a part of the external light is absorbed and reflected by the filter effect of the pigment particles coated on the phosphor surface. Since it reduces light, it can be used to increase the contrast of images, so it has been used for the fluorescent screen of most cathode ray tubes for color TVs. A pigment having a larger amount of pigment particles attached than that of the pigment was used.

Heretofore, as one of typical methods for producing a pigmented phosphor, for example, a phosphor dispersion in which a phosphor is dispersed in one of an aqueous gelatin solution and an aqueous gum arabic solution, and a pigment dispersion in the other are used. A mixture of gelatin and gum arabic (hereinafter referred to as "G / A") is obtained by mixing a pigment dispersion in which particles are dispersed and, if necessary, adding a hardening agent such as formalin to the mixture. Method of coating the phosphor surface with pigment particles through the
No. 3677) has been proposed and put into practical use. However, in a conventional phosphor with pigment, in which pigment particles are adhered to the phosphor surface via G / A, the pigment is completely adhered to the phosphor surface. Because it does not adhere to the pigment, pigment peeling is apt to occur or the coating of the pigment particles on the phosphor surface becomes uneven, and when a phosphor film is formed using this phosphor, the film quality and the obtained image quality are poor. This is particularly noticeable in the case of a phosphor having a relatively large amount of pigment adhering.

In the case of producing a fluorescent screen of a color cathode ray tube, a black matrix layer (hereinafter referred to as "BM") made of a black pigment such as carbon black is first formed on a support (glass). After applying the phosphor slurry of the first emission color containing the photosensitive resin to the entire surface of the formed support, only the desired portion where the BM is not formed is exposed and developed to develop the predetermined gap of the BM. A phosphor film of the first emission color is formed at the position of, and the same procedure of the photolithography method is repeated thereafter to sequentially form the phosphor films of the second and third emission colors in the gaps of the BM on the support. In the conventional phosphor with pigment using G / A, the phosphor particles are liable to be sticky due to excess gelatin attached to the surface. Therefore, when a phosphor screen is manufactured by the phototriso method using the phosphor as described above, , On the BM formed on the support,
Some of the phosphor particles to be applied to a predetermined place other than the BM remain adhered and adhered (hereinafter referred to as “duck fog”), deteriorating the film quality and image quality of the phosphor screen. Was rare. Furthermore, when a phosphor film made of a phosphor of a different color is sequentially formed on the support in addition to the duck fog depending on the surface condition of the phosphor, the fluorescence to be formed later is formed on the phosphor film formed earlier. There has also been a problem that the phosphor particles of the film remain and adhere (hereinafter, referred to as “color mixture”).

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a fluorescent material having good image quality, which has less pigment peeling, uniform pigment adhesion, and is less likely to cause duck fog and color mixing when used as a fluorescent film, and has excellent coating characteristics. An object of the present invention is to provide a phosphor with a pigment that can obtain a surface and a method for producing the same.

[0006]

The configuration of the present invention is as follows. (1) Pigment adheres via a second film made of a mixture of gelatin and gum arabic to a first film made of a mixture of gelatin and gum arabic formed on the surface of the phosphor particles A phosphor with a pigment. (2) The first coating made of a mixture of the gelatin and the gum arabic is 0.0001 to 0.
The phosphor with a pigment according to the above (1), which is 1% by weight. (3) The total amount of the first film and the second film made of a mixture of the gelatin and the gum arabic is 0.05 to 0.8% by weight based on the phosphor. ) Or the phosphor with a pigment according to (2).

(4) The phosphor with a pigment according to any one of (1) to (3), wherein the amount of the pigment attached is 0.05 to 10% by weight based on the phosphor. . (5) A surface treatment agent comprising at least one of zinc citrate, zinc alginate, zinc hydroxide and zinc oxide is further provided on the outermost surface of the phosphor to which the pigment is attached. (1) characterized by being coated
The phosphor with a pigment according to any one of (1) to (4). (6) A first mixture of gelatin and gum arabic is added to a phosphor slurry in which the phosphor is dispersed in water, and the first slurry is adjusted by adjusting the pH value of the phosphor slurry.
Gelling the mixture to form a first film made of the first mixture on the surface of the phosphor, and then pigment particles,
And adding a second mixture of gelatin and gum arabic, and then adjusting the pH value of the phosphor slurry to gel the second mixture to form the second mixture through a second film. A method for producing a pigmented phosphor, wherein the pigment particles are adhered on the film of (1).

(7) The method for producing a phosphor with a pigment according to (6), wherein the pH value of the phosphor slurry is in a range of 3.5 to 4.5. (8) The pigment according to (6) or (7), wherein the first mixture of the gelatin and the gum arabic is 0.0001 to 0.1% by weight based on the phosphor. A method for producing a phosphor. (9) The total amount of the first mixture of the gelatin and the gum arabic and the second mixture is 0.
(6) wherein the content is from 0.5 to 0.8% by weight.
A method for producing the phosphor with a pigment according to any one of (1) to (8).

(10) Pigment particles comprising a mixture of the above-mentioned gelatin and arabic gum are used in an amount of 0.0
(6) to (10), wherein the content is 5 to 10% by weight.
(9) The method for producing a pigmented phosphor according to any one of (9). (11) The fluorescence with a pigment according to any one of (6) to (10), wherein the second film is gelled and then dehydrated, and then heated at a temperature of 100 to 250 ° C. How to make the body.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In order to produce the pigmented phosphor of the present invention, first, a phosphor is suspended in water to prepare an aqueous slurry of the phosphor, and G is separately prepared in the phosphor slurry.
/ A, and then a weak mineral acid such as acetic acid is added and sufficiently stirred, so that the pH value of the slurry is about 5 or less, more preferably 3.5 to 3.5.
G / A is gelled in the slurry by adjusting so as to fall within the range of 4.5, and a first coating of G / A is first formed on the surface of the phosphor particles.

Next, a predetermined amount of pigment particles is added to the slurry, a predetermined amount of G / A separately prepared is added thereto while stirring and mixing, and the pH of the phosphor slurry is reduced to about 5 or less again. More preferably, a second film made of G / A gelled in the slurry is formed by adjusting so as to be in the range of 3.5 to 4.5, and the phosphor is formed via the second film. Pigment particles adhere to the surface of the substrate. The phrase “pigment particles adhere to the phosphor via the second film” means that, when the pigment particles adhere to the second film formed on the first film, When it adheres to the first film in a state where it is entangled with the second film, it adheres to the first film and is covered with the second film from above. It refers to a state in which the pigment particles are in contact with the pigment particles and adhere to the first film in some way.

Subsequently, the phosphor slurry is dehydrated,
The pigmented phosphor obtained by drying is further added to
First and second layers of the gelled G / A on the phosphor surface when heated at 0 to 220 ° C, more preferably 180 to 200 ° C.
Is cured to obtain the pigmented phosphor of the present invention. In a conventional phosphor with a pigment, a curing agent such as glutaraldehyde was added and cured in order to cure the G / A on the surface of the phosphor. Since the charge becomes negative (-) and the underlayer (support) on which the fluorescent film is formed is positive (+) in many cases, this causes duck fog. A state in which the charge on the phosphor surface is kept positive (+) by gelling by adjusting the pH in the slurry without using the curing agent of A, and further heating and curing the gel at a temperature of 150 to 250 ° C. G / A can be cured by the method described above, which is more preferable because the factor of duck fog at the time of forming the fluorescent film can be reduced.

In producing the phosphor of the present invention, the amount of G / A used is about 0.0
Suitably 5 to 0.8% by weight, more preferably 0.1 to 0.3% by weight, of which about 10 to 50% is added first and deposited with this first G / A. It is preferable to form a first G / A coating, which serves as a base for the pigment particles.

The amount of the pigment to be added depends on whether the pigment is a red pigment or a blue pigment. If the pigment is a red pigment, it may be about 0.05 to 1.0% by weight based on the phosphor. In this case, the content may be about 1 to 10% by weight based on the phosphor. However, in the method for producing a phosphor with a pigment of the present invention, if the pigment is a red pigment, the adhesion amount is 0.2 to 1.0.
%, And if the pigment is a blue pigment, the adhesion amount is 3 to 10%.
This is a particularly suitable method for producing a pigmented phosphor to which a pigment having a high concentration such as by weight is attached.

The phosphor used for the pigmented phosphor of the present invention is not particularly limited, and emits blue light such as Y ₂ O ₂ S: Eu and Y ₂ O ₃ : Eu which emit red light under electron beam excitation. Presenting ZnS: Ag, ZnS: Ag, Cl, ZnS: A
g, Al, etc., ZnS that emits green light: Cu, Cl, Z
Phosphors conventionally used for a phosphor screen for a cathode ray tube, such as nS: Cu, Al and ZnS: Au, Al, are used.
There is no particular limitation on the pigment used, and red pigments such as red iron oxide and cadmium sulfate selenide are used for red light emitting phosphors, and blue pigments such as cobalt blue and ultramarine blue are used for blue light emitting phosphors. Green pigments such as chrome green and chromium oxide are used for the green light emitting phosphor.

As described above, the pigment-coated phosphor having the G / A film formed on the surface thereof and having the pigment adhered thereto via the G / A film has a higher dispersibility. Acrylic resin that has been used as a surface treatment agent on the phosphor surface, and has been used as a surface treatment agent for phosphors in order to further improve coating properties such as preventing color mixing and improving exposure sensitivity when creating phosphor screens by the photolithographic method Alternatively, a metal salt film such as alginic acid, chito acid, citric acid, etc. may be formed, or an inorganic film such as zinc oxide, zinc hydroxide, colloidal silica, alumina sol, titania sol, etc. may be formed.

The pigment-containing phosphor of the present invention thus produced has less peeling of the pigment even if the coating amount of the pigment is larger than that of the conventional phosphor, and the amount of G / A used is reduced. Since it is used after being dispersed before and after the pigment is attached to the surface, the amount of G / A exposed on the outermost surface of the phosphor can be smaller than that of the conventional phosphor with a pigment. Since the sticking phenomenon on the phosphor surface can be further suppressed, the phosphor with the pigment of the present invention is formed of BM, green, blue and red phosphors composed of black pigments on the face plate of a color cathode-ray tube by the photolithography method using the photolithography method. When a phosphor screen is formed by sequentially forming phosphor films, duck fog is significantly reduced and fog (color mixture) on a phosphor film of another color (base) can be reduced as compared with the case where a conventional phosphor with pigment is used. .

[0018]

Next, the present invention will be described by way of examples. [Example 1] 100 parts by weight of Y ₂ O ₂ S: Eu phosphor
A phosphor slurry is prepared by suspending in 00 parts by weight of water,
0.02 parts by weight of gelatin and gum arabic were added to the slurry with respect to the phosphor, and acetic acid was added with sufficient stirring until the pH value of the slurry became 4, and gelatin was added to the surface of the phosphor. A first film made of a mixture of styrene and gum arabic was formed.

Next, 0.22 parts by weight of petiole pigment was added to the phosphor, and the mixture was thoroughly stirred. Then, 0.08 parts by weight of gelatin and gum arabic were added to the phosphor, and acetic acid was added. After sufficiently adjusting the pH value of the slurry to 4 again while gradually adding the slurry, the supernatant was once removed, washed and dehydrated, and then water was added again to form a slurry.
A small amount of citric acid sodium, sodium alginate and zinc sulfate are added to give a surface treatment to adhere to the surface of the phosphor, dehydrated, dried, heated at 190 ° C. for 1 hour, sieved, and gelatin and gum arabic are added. And a pigmented phosphor of Example 1 in which a first film made of a mixture of the above was formed and a reddish stem was further adhered thereon via a second film made of a mixture of gelatin and gum arabic. .

Comparative Example 1 100 parts by weight of Y ₂ O ₂ S:
The Eu phosphor is suspended in 200 parts by weight of water to prepare a phosphor slurry, in which 0.22 parts by weight of red-pebble pigment, 0.1 parts by weight of gelatin and 0.1 parts by weight of gum arabic Was added, and the mixture was stirred sufficiently while adding acetic acid to adjust the pH value of the slurry to 4, and then the supernatant was once removed,
Water is added again to form a slurry, 0.5 parts by weight of glutaraldehyde is added thereto, and the mixture is stirred and allowed to stand. Then, a small amount of citric acid, alginic acid and zinc sulfate are added to the surface to be attached to the surface of the phosphor. After treatment, dehydrated, 12
It was dried at 0 ° C. and sieved to obtain a pigmented phosphor of Comparative Example 1.

The pigmented phosphors of Example 1 and Comparative Example 1 obtained as described above were subjected to a pigment peeling test and a duck fogging test to determine the degree of pigment peeling of each pigmented phosphor and the phosphors. Was used to examine the degree of duck fog when the fluorescent film was formed.

In the pigment peeling test, a snake pump for transporting a liquid was used, and the slurry of each phosphor was circulated through the pump for 60 minutes.
5 mmφ, injected into a 300 mm long cylindrical glass sedimentation tube, left for 24 hours to sediment the phosphor,
The transmittance at the time when 500 nm light was transmitted to the supernatant liquid above the sedimentation tube was measured, and the magnitude of the transmittance was compared to evaluate the degree of pigment peeling of the phosphor. As a light source at the time of transmittance measurement, light from an incandescent lamp transmitted through a bandpass filter that transmits light near 500 nm is used.
Each sample supernatant was irradiated with light from this light source and transmitted, and the transmittance at that time was measured and shown as a relative value to the transmittance of the standard sample solution. Note that transparent water was used as a standard sample.

As a result, the transmittance of the pigmented phosphor of Example 1 was 30%, while the transmittance of the pigmented phosphor of Comparative Example 1 was 24%. The peeling of the pigment of the phosphor with a pigment was significantly less than that of the phosphor of Comparative Example 1 which is a conventional phosphor with a pigment.

On the other hand, in the duck fog judgment test, after a coating film made of a black pigment is formed on the entire surface of the glass panel by the photolithography method, a phosphor slurry containing a photosensitive resin is applied on the entire surface, and a normal phosphor film is formed. After exposing the entire surface with a light amount smaller than the exposure amount when forming, the entire surface is developed (washed out), and then dried. The amount of the attached phosphor particles was relatively determined, and the case where no phosphor particles were observed on the coating film composed of the black pigment was evaluated as 5 points.
The degree of duck fog of each sample was expressed as a score, and the degree of duck fog was relatively evaluated by making the score perfect and deducting the points each time the number of phosphor particles attached to the coating film increased.

As a result, in the case of the phosphor with the pigment of Example 1, the score was 4.5 points, whereas in the case of the fluorescent with the pigment of Comparative Example 1, it was 3.7 points. When a phosphor film is formed using a pigmented phosphor of the related art, it is a conventional phosphor,
Duck fog was significantly reduced as compared with the case where a phosphor film was prepared using the phosphor with pigment of Comparative Example 1.

Example 2 ZnS: Ag, Al phosphor 1
A phosphor slurry was prepared by suspending 00 parts by weight in 220 parts by weight of water, and 0.08 parts by weight of gelatin and gum arabic were added to the slurry, and acetic acid was added. The pH value of the slurry was adjusted to 4 while stirring sufficiently to form a first film made of a mixture of gelatin and gum arabic on the surface of the phosphor.

Next, 4.0 parts by weight of a cobalt aluminate blue pigment with respect to the phosphor and 0.12 parts by weight of gelatin and gum arabic with respect to the phosphor were added. After sufficiently stirring while gradually adding acetic acid until the mixture becomes 4, the supernatant liquid was once removed, washed with water, dehydrated, and then re-slurried with water, and a small amount of citric acid, alginic acid and zinc sulfate were added. After the surface treatment for attaching to the surface of the phosphor is performed, dehydration is performed, and after drying, the supernatant is removed again, heated at 190 ° C. for 1 hour, dried, and then sieved to obtain a mixture of gelatin and gum arabic. The phosphor with pigment according to Example 2, wherein a first film made of chromium was formed and cobalt aluminate was further adhered thereon via a second film made of a mixture of gelatin and gum arabic. Obtained.

Comparative Example 2 100 parts by weight of ZnS: A
g, Al phosphor was suspended in 200 parts by weight of water to prepare a phosphor slurry, in which 4.0 parts by weight of a cobalt aluminate blue pigment, 0.2 parts by weight of gelatin and gum arabic, respectively. Was added, and the mixture was stirred sufficiently while adding acetic acid to adjust the pH value of the slurry to 4. Then, the supernatant was once removed, and water was added again to form a slurry, and 1.8 parts by weight of glutaraldehyde was added thereto. After stirring and standing, a small amount of citric acid, alginic acid and zinc sulfate were added to perform a surface treatment to adhere to the surface of the phosphor, followed by dehydration, drying at 120 ° C., and sieving. Was obtained.

Next, for each of the phosphors of Example 2 and Comparative Example 2, a pigment peeling test and a duck fog judgment test were performed in exactly the same manner as in the case of the phosphor of Example 1 and the phosphor of Comparative Example 1. The degree of pigment peeling and the degree of duck fog of each phosphor were examined.

As a result of the pigment peeling test, the transmittance of the phosphor of Example 2 was 28%, whereas the transmittance of the phosphor of Comparative Example 2 was 23%. The degree of pigment peeling of the pigmented phosphor was significantly improved as compared with the conventional pigmented phosphor of Comparative Example 2 which is a pigmented phosphor.

On the other hand, as a result of the duck fog test,
When the phosphor film was formed using the phosphor of Comparative Example 2, the score was 4.8 points, whereas when the phosphor film was formed using the phosphor of Comparative Example 2, the score was 3.9 points. When a phosphor film was prepared using the phosphor with pigment of Example 2, the degree of duck fog was significantly reduced as compared with the case of using the phosphor of Comparative Example 2 which is a conventional phosphor with pigment.

[0032]

As described above, the pigmented phosphor produced by the production method of the present invention is less likely to cause pigment peeling than the conventional pigmented phosphor, and when a phosphor film is formed using this phosphor, duck fog, Color mixing is remarkably reduced, and a fluorescent film having good film quality and good image quality can be formed.

Claims (11)

[Claims] 1. A first film comprising a mixture of gelatin and gum arabic formed on the surface of phosphor particles,
A pigment-coated phosphor, wherein the pigment is attached via a second film made of a mixture of gelatin and gum arabic. 2. A method according to claim 1, wherein the first coating comprising a mixture of gelatin and gum arabic is 0.0001 to the phosphor.
The pigment-containing phosphor according to claim 1, wherein the content is from 0.1 to 0.1% by weight. 3. The phosphor according to claim 1, wherein the total amount of the first coating and the second coating made of a mixture of gelatin and gum arabic is 0.05 to 0.8% by weight based on the phosphor. Item 3. The phosphor with a pigment according to Item 1 or 2. 4. The method according to claim 1, wherein the amount of the pigment attached is 0.05 to 10% by weight based on the phosphor.
The phosphor with a pigment according to any one of Items 1 to 3. 5. A surface treatment further comprising at least one of zinc citrate, zinc alginate, zinc hydroxide and zinc oxide on the outermost surface of the phosphor to which the pigment is attached. The phosphor with a pigment according to any one of claims 1 to 4, wherein the phosphor is coated with an agent. 6. A first mixture of gelatin and gum arabic is added to a phosphor slurry in which a phosphor is dispersed in water, and the first mixture is adjusted by adjusting the pH value of the phosphor slurry. After gelling to form a first film made of the first mixture on the surface of the phosphor, pigment particles and a second mixture of gelatin and gum arabic are added, and then the phosphor slurry Wherein the pigment particles are adhered onto the first film via a second film obtained by gelling the second mixture by adjusting the pH value of the phosphor with a pigment. Manufacturing method. 7. The method for producing a phosphor with a pigment according to claim 6, wherein a pH value of the phosphor slurry is in a range of 3.5 to 4.5. 8. The pigmented fluorescence according to claim 6, wherein the first mixture of the gelatin and the gum arabic is 0.0001 to 0.1% by weight based on the phosphor. How to make the body. 9. The phosphor according to claim 6, wherein the total amount of the first mixture and the second mixture of the gelatin and the gum arabic is 0.05 to 0.8% by weight based on the phosphor. 9. The method for producing the phosphor with a pigment according to any one of 8 above. 10. The phosphor according to claim 6, wherein the content of the pigment particles is 0.05 to 10% by weight based on the phosphor.
10. A method for producing the phosphor with a pigment according to any one of items 9 to 9. 11. The method according to claim 6, wherein the second film comprising a mixture of gelatin and gum arabic is gelled and then dehydrated, and then heated at a temperature of 100 to 250 ° C. A method for producing the phosphor with a pigment according to any one of the preceding claims.