JP3372966B2 - Red light-emitting phosphor with pigment and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pigmented red light emitting phosphor suitable for a fluorescent film such as a color cathode ray tube and a method for producing the same.

[0002]

2. Description of the Related Art It is known that a filter material that absorbs reflection of external light on a fluorescent screen is attached to the surface of a phosphor in order to improve the contrast of an image of a color cathode ray tube or a fluorescent display tube. Further, a filter material may be attached to the surface of the phosphor in order to sharpen the emission spectrum of the phosphor. The red light-emitting phosphor with pigment is
Usually, a red iron oxide having a particle size of about 0.1 to 0.5 μm is attached to the surface of the phosphor with a binder (SBR, gelatin, acrylic polymer, etc.). There is a problem that the phosphors are aggregated to deteriorate the characteristics of the fluorescent film. In addition, in recent years, there has been a demand for improvement in contrast, and it is necessary to increase the amount of pigment deposited to be about 5 times or more than the conventional amount. However, since an increase in the amount deposited causes an increase in binder, excellent fluorescent film characteristics are obtained. It becomes even more difficult, and the increase in the amount of pigment adhering causes a problem that the pigment once adhering is peeled off at the time of application to a cathode ray tube.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above problems, suppresses the aggregation of the pigment when the pigment is attached to the phosphor, and is capable of attaching a large amount of the pigment with a strong adhesive force. It is intended to provide a light emitting phosphor and a method for manufacturing the same.

[0004]

The present invention provides (1) with pigment
In the method for producing a red light emitting phosphor, a red light emitting phosphor
Preliminary coating of metal oxide and / or hydrated oxide on the surface
After being formed, the phosphor is dispersed in an iron-containing dispersion liquid,
An iron compound is deposited on the surface of the phosphor by decomposition and
Characterized by being oxidized and deposited as iron (III) oxide
A method for producing a red light-emitting phosphor with a pigment, (2) above (1)
In the method for producing a red light-emitting phosphor with a pigment according to,
Undercoat material is aluminum oxide and / or hydration
Of a red light emitting phosphor with a pigment characterized by being an oxide
Manufacturing method, (3) Manufacturing method according to (1) or (2) above
Red luminescent firefly with pigment characterized by being manufactured by the method
It is a light body .

[0005]

The present inventors have conducted various studies on the agglomeration and adhesion of the red metal when attaching the red metal to the surface of the red light emitting phosphor.
After forming an undercoat of a metal oxide or hydroxide of i, Ti, Co, Zr, etc., by attaching a red iron without using a binder, the adhesiveness is improved while preventing aggregation from the iron. In addition, it was possible to deactivate the phosphor base by the undercoat, and succeeded in maintaining the high brightness of the phosphor. Regarding Al as the undercoat material, the same effect as the above method can be obtained by co-precipitating with iron as the iron oxide raw material and adhering it as aluminum oxide and / or aluminum hydroxide with the iron oxide on the phosphor surface. Also succeeded.

The method for producing the red light-emitting phosphor with pigment of the present invention is as follows.
A method for producing a pigmented red light-emitting phosphor characterized in that iron (III) oxide is attached by any one of a hydrolysis method, a hydrothermal synthesis method, a solvent heating synthesis method and an alkoxide method. . The above-mentioned hydrolysis method uses Al, Zn, Si, T
The red light emitting phosphor is dispersed in an aqueous solution containing a metal such as i, Co or Zr, and the pH is adjusted so that a metal oxide such as Al, Zn, Si, Ti, Co, Zr or the like is formed on the surface of the phosphor. An undercoat of hydroxide is formed, then the above phosphor is dispersed in an iron salt aqueous solution, an iron compound is precipitated by hydrolysis, etc., and after filtering and washing with water, it is dried and heated to oxidize iron (III) oxide. The method for producing a red light-emitting phosphor with a pigment is characterized in that:

In this method, sodium aluminate or the like can be used as the metal-containing aqueous solution forming the undercoat. The amount of the base film deposited on the phosphor is preferably about 0.01 to 0.3% by weight.
If it deviates from this range, the luminance or chromaticity will decrease. Further, as the iron raw material, an aqueous solution of chloride, bromide, sulfate, nitrate or the like or iron oxide sol can be used,
As the precipitating agent, sodium hydroxide, sodium carbonate or the like can be used. The heating oxidation temperature is about 200.
A range of up to 1200 ° C is suitable. Iron (III) oxide attached to the surface of the phosphor is [Fe ₂ O ₃ · nH ₂ O (0 ≦ n ≦
3)] and includes hydrated iron oxide. The single particle diameter is in the range of about 100 to 1000 angstroms, the film thickness is in the range of about 100 to 1500 angstroms, and the adhesion amount is 0.02 to 5.0% by weight with respect to the phosphor as a pigment. Range is suitable. 0.
If it is less than 02% by weight, the filter effect cannot be obtained,
If it exceeds 5.0% by weight, the emission brightness of the phosphor decreases, which is not preferable. The preferable range of this adhesion amount is 0.
It is 1 to 2.0% by weight.

[0008]

In the above manufacturing method, it is also possible to improve the filter characteristics by adding an oxidizing agent to the dispersion liquid to accelerate the oxidation reaction. As an oxidant,
Oxygen, ozone, hydrogen peroxide, sodium peroxodisulfate and the like can be used. Further, in the above-mentioned manufacturing method, in addition to the heat oxidation treatment, by irradiating the dried pigmented red light-emitting phosphor with vacuum ultraviolet rays or short wavelength ultraviolet rays in a vacuum or an inert atmosphere, it is possible to improve the filter characteristics. Is also possible. The intensity of vacuum ultraviolet rays or short wavelength ultraviolet rays is usually 0.5 mW / cm ² or more, and argon, nitrogen or the like can be used as the inert atmosphere.

If desired, various mineralizing agents and other elements can be added to the heating and oxidizing step of the above-mentioned manufacturing method. Specifically, Li, Na, K, B, Mo or the like may be contained. These elements can be added in the range of about 5% by weight or less in the attached pigment. If it exceeds this, it becomes impossible to obtain a preferable color tone as a red pigment.

The red light emitting phosphor that can be used in the present invention has a main part of the emission spectrum within the range of 580 to 700 nm, and more specifically, Y ₂ O ₂
S: Eu, Y ₂ O ₃ : Eu, YVO ₄ : Eu, Zn
₃ (PO ₄ ) ₂ : Mn, MgSiO ₃ : Mn, (Zn,
Cd) S: Ag etc. can be mentioned. The amount of the red pigment attached is preferably in the range of 0.02 to 5% by weight with respect to the phosphor. If the adhered amount is less than the above lower limit value, the filter effect is too small, and if it exceeds the upper limit value, the emission brightness may not be sufficient.

[0012]

【Example】

(Example 1) Aluminum hydroxide (0.2% in terms of alumina) was previously deposited on the surface of the phosphor using an aqueous solution of sodium aluminate, the average particle size was 5 μm, and the specific surface area was 0.1.
1 kg of 3 mm ² / g Y ₂ O ₂ S: Eu phosphor particles was added to 4 kg of deionized water at a temperature of about 60 ° C. to form a slurry, and sodium hydroxide was added to adjust the pH to about 5. While maintaining this pH constant and performing strong stirring, an aqueous solution of ferrous sulfate (FeSO ₄ ) (0.4% relative to the phosphor as a pigment) was added little by little and hydrolyzed. A hydrated oxide is deposited on the surface of the phosphor, and then
The phosphor was dehydrated, heated to about 180 ° C. in the air and dried for 5 hours, and then heated and oxidized in the air at 700 ° C. for 5 hours to obtain a red light emitting phosphor with red iron oxide.

[0013]

Comparative Example 1 Deionized water 4 at a temperature of about 60 ° C.
Y having an average particle diameter of 5 μm and a specific surface area of 0.3 m ² / g per kg
_After adding 1 kg of ₂ O ₂ S: Eu phosphor particles to form a slurry, 0.3% by weight of an acrylic emulsion (AC-61 manufactured by Nippon Acrylic Co., Ltd.) was added as a binder,
Bengal pigment (R-2199 manufactured by Pfizer Inc., average particle size 0.25 μm) was attached at 0.4% by weight by a pH adjusting method, dehydrated, and dried at 120 ° C. for 5 hours to obtain a red phosphor with red iron. .

Comparative Example 2 4 kg of deionized water having a temperature of about 30 ° C., an average particle size of 5 μm,
1 kg of Y ₂ O ₂ S: Eu phosphor particles having a specific surface area of 0.3 m ² / g and ferric hydroxide (Fe (OH) ₃ ) (0.5% based on the phosphor) are added to the slurry. After forming
Air was blown into the slurry at 2 liters / minute to deposit 0.5% by weight of α-FeO (OH) on the phosphor surface, dehydrated and dried, and fired at 700 ° C. for 5 hours in the atmosphere to emit red light with red iron oxide. A phosphor was obtained.

(Comparative Example 3) A red light emitting phosphor with red iron oxide was obtained in the same manner as in Example 1 except that the aluminum hydroxide undercoating was omitted.

(Evaluation of Phosphor) Adhesion amount of red iron oxide to the phosphor The phosphor with pigment is dissolved in an acid, and Fe ³⁺ ions and Al ³⁺ ions in the solution are measured by an atomic absorption spectrometry method to obtain a metal oxide. was converted to example 1及 beauty Comparative example 3 are both 0.35 wt%, Comparative examples 1 and 2, both 0.
It was 4% by weight. The state of adhesion was visually evaluated by observing the sample with a scanning electron microscope (SEM) at a magnification of 50,000 times.
Whereas it is 1500 angstroms or less in Example 1及 beauty Comparative Example 3, Comparative Example 1, there are clumps of 2,000 to 8,000 angstroms, In Comparative Example 2,
There was a lump over 1500 angstroms. The pigmented phosphors of Bengala's recovery and reproducibility-resistant Examples and Comparative Examples were dispersed in an aqueous solution containing polyvinyl alcohol, ammonium dichromate and a surfactant to prepare a slurry, which was then applied to a glass face to produce an excess. Of the phosphor of 80 ℃, pH1
Washed with 2 sodium hydroxide solution, was visually observed color tone of the resulting phosphor, Example 1及 beauty Comparative Example 3
In the case of Comparative Example 1, there was no change in the color tone of the phosphor, which was good. However, in Comparative Example 1, peeling of the glass was severe, and recovery and regeneration were impossible. Also in Comparative Example 2, there was peeling of the red iron oxide,
The recovered regenerated phosphor was somewhat defective. Fluorescent film characteristics Luminous properties (luminance), film density (pinholes generated in the fluorescent film), and the degree of mixing (color mixing) of other luminescent components (for example, blue component) into the fluorescent film were visually observed. 1 is
The film density and the emission brightness were good, but Comparative Examples 1 and 2
Had poor film density and emission luminance. Further, in Comparative Example 3, both the film density and the emission brightness were slightly poor. Examination of the ratio by measuring the contrast characteristic 620nm reflectance and 500nm reflectance, Example 1, but sufficient improvement in contrast was observed, the improvement of the contrast of the comparative examples 1, 2 and 3, carried out example was 1'm Riyaya low value.

[0018]

EFFECTS OF THE INVENTION The present invention, by adopting the above-mentioned constitution, has less aggregation at the time of pigment adhesion, has good pigment adhesion, has no change in color tone, and has excellent luminous brightness and contrast. A phosphor can now be provided.

Front page continued (72) Inventor friend Mizukami 1060 Narita, Odawara-shi, Kanagawa Kasei Optronics Co., Ltd. Odawara factory (56) References JP-A-54-28784 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) C09K 11/08 H01J 29/10-29/34 H01J 29/46 H01J 31/00-31/24 H01J 61/30-61/48 H01J 9/20-9/236

Claims (3)

(57) [Claims] 1. A method for producing a red light emitting phosphor with a pigment.
The metal oxide and / or water on the surface of the red-emitting phosphor.
After forming the underlying film of hydrated oxide, the phosphor is treated with iron-containing component.
Disperse in a dispersion liquid and hydrolyze the iron compound on the surface of the phosphor.
Precipitates a substance, oxidizes it and attaches it as iron (III) oxide
For producing a red light-emitting phosphor with a pigment characterized by
Law. 2. A red light emitting phosphor with a pigment according to claim 1.
In the manufacturing method, the undercoat material is an oxide of aluminum and / or
Pigmented red emission fluorescence characterized by being a hydrated oxide
Body manufacturing method. 3. The manufacturing method according to claim 1 or 2.
A red light-emitting phosphor with a pigment, which is manufactured.