JP4375014B2 - Phosphor for vacuum ultraviolet light-emitting device - Google Patents

Description

    The present invention relates to a phosphor for a vacuum ultraviolet ray-excited light emitting device.

The phosphor for a vacuum ultraviolet ray excited light emitting element is used for a vacuum ultraviolet ray excited light emitting element such as a PDP or a rare gas lamp, and a phosphor that emits light when excited by a vacuum ultraviolet ray is already known. Among them, as phosphors for green-emitting vacuum ultraviolet light-excited light emitting elements, aluminate phosphors BaAl ₁₂ O ₁₉ : Mn (see, for example, Patent Document 1) and silicate phosphors Zn ₂ SiO _{4 are used.} : Mn has been put to practical use.

  Here, the vacuum ultraviolet-excited light emitting element generates plasma by discharge in a rare gas, and excites the phosphor by irradiating the phosphor arranged near the place where the plasma was generated with vacuum ultraviolet rays emitted from the plasma. In addition, visible light is emitted from the phosphor, and the visible light is emitted from the element. For this reason, the phosphor is exposed to plasma. Conventional phosphors have a problem that the luminance of the phosphor is lowered after the plasma exposure, and there has been a demand for a phosphor with a small decrease in luminance after the plasma exposure.

JP 2003-242889 A

The present inventors have been represented by a fluorescent substance composed of a compound represented by the formula La _0.6 Ba _0.4 (Mg _0.65 Zn _0.3 Mn _0.05 ) Al ₁₁ O _18.8 as a green phosphor with little decrease in luminance after plasma exposure. , Formula (1)
(M ¹ _1-a M ² _a ) (Mg _1-bc Zn _b ) Al _11-d Mn _{c + d} O _{19- (a + d) / 2} (1)
(In the formula, M ¹ is one or more selected from the group consisting of La, Y and Gd, M ² is one or more selected from the group consisting of Ca, Sr and Ba, and a is 0 or more and 0.00. 6 or less, b is 0 or more and 1 or less, c is 0 or more and 0.5 or less, d is 0 or more and 0.5 or less, and b + c is 1 or less , C + d is in the range of more than 0 and less than or equal to 0.5.) Has been proposed (Japanese Patent Application No. 2003-200309) as a phosphor for a green-emitting vacuum ultraviolet-excited light emitting device. The brightness after plasma exposure was not enough. Accordingly, there has been a demand for a phosphor for a vacuum ultraviolet ray-excited light emitting device having a higher luminance after plasma exposure.

  The objective of this invention is providing the fluorescent substance for vacuum ultraviolet ray excitation light emitting elements with the high brightness | luminance after plasma exposure.

  Under these circumstances, the present inventors have conducted extensive studies to solve the above-mentioned problems, and as a result, the fluorescent substance and silicate composed of the specific aluminate represented by the formula (1) are used as activators. The present inventors have found that a phosphor containing both a phosphor containing Mn exhibits high brightness after plasma exposure, and has completed the present invention.

That is, in the present invention, as the first component, the formula (M ¹ _1-a M ² _a ) (Mg _1-bc Zn _b ) Al _11-d Mn _{c + d} O _{19- (a + d) / 2} (formula M ¹ therein is one or more selected from the group consisting of La, Y and Gd, M ² is one or more selected from the group consisting of Ca, Sr and Ba, and a is 0 or more and 0.6 or less. B is a range of 0 or more and 1 or less, c is a range of 0 or more and 0.5 or less, d is a range of 0 or more and 0.5 or less, b + c is 1 or less, and c + d Is in the range of more than 0 and less than or equal to 0.5.) And a fluorescent material containing Mn as an activator in silicate as the second component A phosphor for a vacuum ultraviolet ray-excited light emitting device is provided. The present invention also provides a phosphor paste comprising the phosphor described above, a solvent, and a binder.

  The phosphor of the present invention has high brightness after plasma exposure, and is particularly suitable for vacuum ultraviolet light-excited light emitting elements such as PDPs and rare gas lamps. It is extremely useful industrially.

The present invention is described in detail below.
The phosphor of the present invention has the formula (1) as the first component.
(M ¹ _1-a M ² _a ) (Mg _1-bc Zn _b ) Al _11-d Mn _{c + d} O _{19- (a + d) / 2} (1)
The fluorescent substance which consists of a compound represented by these is included. M ¹ in the formula is one or more selected from the group consisting of La, Y and Gd, M ² is one or more selected from the group consisting of Ca, Sr and Ba, and a is 0 or more and 0.6. B is a range of 0 or more and 1 or less, c is a range of 0 or more and 0.5 or less, d is a range of 0 or more and 0.5 or less, and b + c is 1 or less, c + d is in the range of more than 0 and 0.5 or less. c + d is preferably in the range of 0.001 to 0.2.

As the first component, in the formula (1), the formula (2) in which Al is exactly 11 moles
(M ¹ _1-a M ² _a ) (Mg _1-bc Zn _b Mn _c ) Al ₁₁ O _{19- (a / 2)} (2)
The fluorescent substance which consists of a compound represented by these is preferable. In this case, M ¹ and M ² in the formula have the same meaning as described above, and the values of a, b and c represent the same range as described above.

Further, as the first component, in formula (2), M ¹ is La, M ² is Ba, and a is 0.4 (3)
(La _0.6 Ba _0.4 ) (Mg _{1 -bc} Zn _b Mn _c ) Al ₁₁ O _18.8 (3)
The fluorescent substance which consists of a compound represented by these is further more preferable. B or c in the formula represents the same range as described above.

The phosphor of the present invention contains, as a second component, a fluorescent material in which Mn is contained as an activator in silicate. Although it will not specifically limit if it is a fluorescent substance which consists of silicate containing Mn as an activator, Formula (4)
_{Zn 2-e Mn e SiO 4} (4)
(The e in the formula is more than 0 and not more than 0.3, and preferably in the range of not less than 0.001 and not more than 0.2.)

  The phosphor of the present invention may contain phosphors other than those described above as long as the object of the present invention is not impaired, but those substantially consisting of the first component and the second component are preferable.

  In the phosphor of the present invention, the ratio of the first component to the second component is preferably such that the weight ratio of (first component) / (second component) is from 5/95 to 95/5. The range of 20/80 to 80/20 is more preferable, and the range of 40/60 to 60/40 is more preferable. When the weight ratio of (first component) / (second component) is less than 5/95 and more than 95/5, the brightness after plasma exposure tends to be low.

Next, a method for manufacturing the phosphor of the present invention will be described.
The phosphor of the present invention can be obtained, for example, by mixing the first component and the second component. The mixing can be performed using a stirrer, a ball mill, a V-type mixer, a three-roller, etc., which are usually used industrially.

  Here, the fluorescent material which is the first component and is composed of the compound represented by the formula (1) is, for example, a mixture of metal compounds, which is manufactured by firing a mixture that can become the fluorescent material by firing. be able to. As a lanthanum compound, an yttrium compound, a gadolinium compound, a calcium compound, a strontium compound, a barium compound, a magnesium compound, a zinc compound, an aluminum compound, and a manganese compound for producing a fluorescent substance composed of the compound represented by the formula (1), For example, high-purity (99% or more) hydroxides, carbonates, nitrates, halides, oxalates, etc. that can be decomposed at high temperatures into oxides or high-purity (99% or more) oxides can be used. .

  Moreover, the fluorescent material which is the second component of the phosphor of the present invention and contains Mn as an activator in silicate is, for example, a mixture of metal compounds, and can be converted into the fluorescent material by firing. It can be produced by firing the mixture. For example, as a fluorescent substance in which Mn is contained as an activator in silicate, a zinc compound, a silicon compound, or a manganese compound for producing a fluorescent substance composed of a compound represented by the formula (4) A highly pure (99% or more) hydroxide, carbonate, nitrate, halide, oxalate, or the like that can be decomposed into an oxide at a high temperature or a high purity (99% or more) oxide can be used.

  Any of the above fluorescent substances can be produced by weighing, blending, mixing and firing the above compounds so as to have a predetermined ratio. For mixing these compounds, a ball mill, a V-type mixer, a stirring device or the like which is usually used industrially can be used. After mixing, for example, the phosphor of the first component or the second component in the present invention is obtained by baking for 1 to 100 hours in a temperature range of 1000 ° C. or more and 1500 ° C. or less. In addition, when a compound that can be decomposed at high temperature such as hydroxide, carbonate, nitrate, halide, or oxalate is used as a starting material, the compound that can be converted into an oxide can be changed to an oxide. In order to remove moisture from the mixture of the compounds, calcination may be performed, for example, in a temperature range of 600 ° C. or higher and lower than 900 ° C. before the main baking.

  The firing atmosphere for producing the first component fluorescent material is not particularly limited. For example, 0.1 to 10% by volume of hydrogen is contained in an inert gas such as nitrogen or argon. A reducing atmosphere is preferred. The calcination atmosphere may be either an air atmosphere or a reducing atmosphere. Further, the atmosphere for producing the second component fluorescent material is not particularly limited, but it is preferable to perform firing in an oxygen atmosphere or an oxidizing atmosphere containing nitrogen or argon in addition to oxygen. More preferred is an air atmosphere. The calcination atmosphere may be either an air atmosphere or a reducing atmosphere.

  Furthermore, you may grind | pulverize any said fluorescent substance obtained by the said method, for example using a ball mill, a jet mill, etc. Moreover, you may wash and classify. Moreover, in order to improve the crystallinity of the phosphor particles, the particles may be fired again. Furthermore, in order to increase crystallinity, a flux may be added and fired.

  The phosphor of the present invention can be excited by ultraviolet rays other than the vacuum ultraviolet region, X-rays, electron beams, etc., and the fluorescent lamp, night-light display using ultraviolet rays other than the vacuum ultraviolet region, X-rays and electron beams as excitation sources, It can also be used for X-ray inspection devices, CRTs, and the like.

  Here, PDP is mentioned as an example of the vacuum ultraviolet ray excitation light emitting display element using the fluorescent substance of this invention, and the manufacturing method is demonstrated. As a method for producing the PDP, for example, a known method as disclosed in JP-A-10-195428 can be used. That is, a phosphor paste is manufactured by adding a solvent firefly and an organic binder to each of the phosphors for vacuum ultraviolet light-excited light emitting elements for emitting blue, green and red light. The phosphor paste is applied to the inner surface of the rear substrate of the present invention by a method such as screen printing on the stripe-shaped substrate surface and the partition surface partitioned by the partition and provided with address electrodes, and fired at a temperature range of 300 to 600 ° C. Then, the respective phosphor layers are formed. A surface glass substrate provided with a transparent electrode and a bus electrode in a direction orthogonal to the phosphor layer and provided with a dielectric layer and a protective layer on the inner surface is laminated and bonded thereto. A PDP can be manufactured by exhausting the inside and enclosing a rare gas such as low-pressure Xe or Ne to form a discharge space.

  Next, for example, the phosphor paste for a vacuum ultraviolet light-excited light emitting device used for the production of PDP as described above will be described. The phosphor paste of the present invention is a phosphor paste that contains the phosphor of the present invention, a solvent, and a binder and can be used in the same manner as a conventional phosphor paste, and the phosphor of the present invention remains after firing.

  The phosphor paste of the present invention can be produced by a known method using a known binder and solvent. For example, it can be obtained by mixing the fluorescent material of the first component, the fluorescent material of the second component, a binder, and a solvent using a ball mill, a triple roll, or the like.

  Binders include cellulose resins (ethyl cellulose, methyl cellulose, nitrocellulose, acetyl cellulose, cellulose propionate, hydroxypropyl cellulose, butyl cellulose, benzyl cellulose, modified cellulose, etc.), acrylic resins (acrylic acid, methacrylic acid, methyl acrylate) , Methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, 2-hydroxyethyl acrylate, 2- Hydroxyethyl methacrylate, 2-hydroxypropyl acrylate 2-hydroxypropyl methacrylate, benzyl acrylate, benzyl methacrylate, phenoxy acrylate, phenoxy methacrylate, isobornyl acrylate, isobornyl methacrylate, glycidyl methacrylate, styrene, α-methylstyrene acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, etc. At least one polymer among monomers), ethylene-vinyl acetate copolymer resin, polyvinyl butyral, polyvinyl alcohol, propylene glycol, urethane resin, melamine resin, phenol resin, and the like.

  Examples of the solvent include those having a high boiling point among monohydric alcohols; polyhydric alcohols such as diols and triols typified by ethylene glycol and glycerin; compounds obtained by etherification and / or esterification of alcohols (ethylene glycol monoalkyl ether, Ethylene glycol dialkyl ether, ethylene glycol alkyl ether acetate, diethylene glycol monoalkyl ether acetate, diethylene glycol dialkyl ether, propylene glycol monoalkyl ether, propylene glycol dialkyl ether, propylene glycol alkyl acetate) and the like.

  The phosphor remaining after firing the phosphor paste of the present invention obtained as described above has high brightness after plasma exposure. In the production of PDPs and rare gas lamps, a phosphor is added to a phosphor and mixed with a solvent (that is, made into a phosphor paste), applied to the light emitting part, and heat treated at about 500 ° C. to remove the binder. The process of installing the body is common, but the phosphor of the present invention has a high luminance after the heat treatment. Therefore, when the phosphor of the present invention is used for a vacuum ultraviolet ray excited light emitting device such as a PDP and a rare gas lamp, a high-luminance and long life PDP and a rare gas lamp can be realized. It is.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. In addition, the emission luminance is measured by placing the phosphor in a vacuum chamber, maintaining a vacuum of 6.7 Pa (5 × 10 ⁻² torr) or less, and using an excimer 146 nm lamp (H0012 type manufactured by USHIO INC.). It was performed by irradiating with vacuum ultraviolet rays. In addition, the phosphor was heated in air at 500 ° C. for 30 minutes and then heat-treated in an atmosphere having a pressure of 13.2 Pa and a composition of 5 vol% Xe-95 vol% Ne. After the body was placed and exposed to 50 W plasma for 15 minutes to perform plasma exposure treatment, the luminance was measured in the same manner as described above. The measurement of the color coordinate value (x, y) was performed using a color luminance meter (Model BM-7 manufactured by Topcon Corporation).

Comparative Example 1
In producing Zn _1.9 Mn _0.1 SiO ₄ , zinc oxide (Kyowa Chemical Industry Co., Ltd .: purity 99.9%), silicon dioxide (Nihon Aerosil Co., Ltd .: purity 99.99%) and manganese carbonate (Wako Pure Chemical Industries, Ltd.) Kogyo Co., Ltd .: Purity 99.9%) was weighed in a molar ratio of Zn: Mn: Si = 1.9: 0.1: 1.0, and 4 by a wet ball mill using isopropyl alcohol as a solvent. Mixed for hours. The solvent in the slurry is removed with an evaporator, and the mixed powder obtained by drying is baked by holding it at 1200 ° C. for 2 hours in an air atmosphere using an alumina crucible, and then gradually cooled to room temperature to remove the fluorescent material. Obtained. When the fluorescent material was irradiated with vacuum ultraviolet light of 146 nm, green light emission was observed, and the luminance obtained at this time was set to 100. Next, when the luminance was measured by performing the heat treatment followed by the plasma exposure treatment for this fluorescent substance, the obtained luminance was 56. The color coordinate value (x, y) at this time was (0.256, 0.706).

Comparative Example 2
La _0.6 Ba _0.4 (Mg _0.65 Zn _0.3 Mn _0.05 ) Al ₁₁ O _18.8 (Formula (1): (M ¹ _1-a M ² _a ) (Mg _1-bc Zn _b ) Al _11-d Mn _{c + d} O _{19 -(a + d) / 2 where} M ¹ is La, M ² is Ba, and a = 0.4, b = 0.3, c = 0.05, d = 0. In doing so, lanthanum oxide (manufactured by Shin-Etsu Chemical Co., Ltd .: purity 99.99%), barium carbonate (manufactured by Wako Pure Chemical Industries, Ltd .: purity 99.9%) and basic magnesium carbonate (manufactured by Kyowa Chemical Industry Co., Ltd.): Purity 99% or more), zinc oxide (Kyowa Chemical Industry Co., Ltd .: purity 99.9%), aluminum hydroxide (Sumitomo Chemical Co., Ltd .: purity 99% or more) and manganese carbonate (Wako Pure Chemical Industries, Ltd.) : Purity 99.9%) at a molar ratio of La: Ba: Mg: Zn: Al: Mn = 0.6: 0.4: 0.65 :: 0.3: 1 .0 were weighed so that 0.05, and mixed for 4 hours by a wet ball mill using isopropyl alcohol solvent. The solvent in the slurry was removed with an evaporator, and the mixed powder obtained by drying was calcined by holding it at 1550 ° C. for 24 hours in an air atmosphere using an alumina crucible, and then gradually cooled to room temperature. Next, using an alumina boat, the mixture is refired by holding at 1400 ° C. for 2 hours in a reducing atmosphere of a mixed gas of hydrogen and nitrogen (containing 2% by volume of hydrogen), and then gradually cooled to room temperature. Obtained. When the fluorescent material was irradiated with vacuum ultraviolet rays of 146 nm, green light emission was confirmed, and the luminance obtained at this time was 68. Next, when the same processing as in Comparative Example 1 was performed and the luminance was measured, the obtained luminance was 64, and the color coordinate value (xy) at this time was (0.180 0.739). .

Examples 1-7
The fluorescent material of the first component was produced in the same manner as in Comparative Example 2, and the fluorescent material of the second component was produced in the same manner as in Comparative Example 1. Next, the weight ratio of (first component) / (second component) is 5/95, 20/80, 40/60, 50/50, 60/40, 80/20, 95/5% by weight. In this way, each was weighed, wet-mixed using ethanol, and then dried to obtain a target phosphor. The relative luminance and color coordinate values before and after each treatment were measured through the same operations as in Comparative Example 1.

  Table 1 below shows the relative luminance of the phosphors manufactured in Comparative Examples 1 and 2 and Examples 1 to 7 and the color coordinate values after plasma exposure.

According to the results in Table 1, it was confirmed that the phosphors of Examples 1 to 7 had higher emission luminance after plasma exposure and better green color purity than Comparative Examples 1 and 2.

Claims (5)

As the first component, the formula (M ¹ _1-a M ² _a ) (Mg _1-bc Zn _b ) Al _11-d Mn _{c + d} O _{19- (a + d) / 2} (where M ¹ is La , M ² is Ba , a is in the range of greater than 0 to 0.6, b is in the range of 0 to 1, c is in the range of 0 to 0.5, d Is a range of 0 to 0.5, b + c is 1 or less, c + d is a range of more than 0 and 0.5 or less.) And a fluorescent substance composed of a compound represented by the formula Zn _{2 -e} Mn _e SiO ₄ (wherein e is greater than 0 and less than or equal to 0.3). Phosphor. 2. The phosphor according to claim 1, wherein the first component is a phosphor composed of a compound represented by the formula (La _0.6 Ba _0.4 ) (Mg _0.65 Zn _0.3 Mn _0.05 ) Al ₁₁ O _18.8 . The phosphor according to claim 2, wherein the second component is a phosphor made of a compound represented by the formula Zn _1.9 Mn _0.1 SiO ₄ . The ratio of the first component to the second component is such that the weight ratio of (first component) / (second component) is in the range of 5/95 to 95/5 . the phosphor according to. A phosphor paste comprising the phosphor according to any one of claims 1 to 4, a solvent, and a binder.