JP2004131677A - Divalent metal silicate phosphor, method for producing the same, and phosphor paste composition and vacuum ultraviolet light-excited light-emitting element by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a divalent metal silicate phosphor emitting blue color light and improved with light-emitting efficiency, a phosphor paste composition and a VUV-excited light-emitting element having high luminosity by using the improved phosphor. <P>SOLUTION: This phosphor paste composition is provided by incorporating a specific amount of chlorine in the crystalline matrix of an Eu-activated divalent metal silicate phosphor expressed by compositional formula: CaMgSi<SB>2</SB>O<SB>6</SB>:Eu, making its particle size small and using the phosphor. The VUV-excited light-emitting element is provided by forming its phosphor film with the above phosphor. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a divalent metal silicate phosphor that emits blue light when excited by vacuum ultraviolet (VUV) and ultraviolet (UV) light having a wavelength of 200 nm or less, a method for producing the same, and a phosphor paste composition containing the phosphor. The present invention relates to an object, a vacuum ultraviolet ray excited light emitting element (VUV excited light emitting element), and a fluorescent lamp.
[0002]
[Prior art]
In recent years, rare gases such as Ar, Xe, He, Ne, or a mixed gas of these gases are used as glass, as represented by rare gas lamps and plasma display panels (PDPs) used as light sources for reading scanners. Of a VUV-excited light-emitting element having a structure in which a fluorescent film made of a VUV phosphor inside the envelope is excited by VUV emitted by the discharge of the rare gas to emit light by being enclosed in the envelope formed by the method described above. Is being actively conducted.
[0003]
A rare gas lamp, which is a typical example of a VUV-excited light emitting device, has a rare gas such as Xe or Xe-Ne sealed in a thin tube made of glass, and the inner wall surface of the tube emits light when excited by VUV. A phosphor film made of a VUV phosphor is formed. When electric energy is applied between the electrodes of the rare gas lamp, a rare gas discharge occurs in the glass tube, and the VUV emitted at that time excites the fluorescent film formed on the inner wall surface of the tube to emit visible light. .
[0004]
In principle, a PDP, which is another typical example of a VUV-excited light-emitting device, has the above-mentioned VUV-excited rare gas lamps further reduced in size, and rare gas lamps of three different colors are arranged in stripes or in a matrix. Can be thought of. That is, narrow discharge spaces (cells) are arranged in a stripe or a matrix. Each cell is provided with an electrode, and a fluorescent film made of a VUV phosphor is formed inside each cell. Each cell is filled with a rare gas such as Xe, Xe-Ne, He-Xe, He-Ne-Xe, etc. When electric energy is applied from an electrode in the cell, a rare gas discharge occurs in the cell and VUV occurs. Is emitted, and the fluorescent film in the cell is excited by the VUV to emit visible light, and an image is displayed by the emitted light. In the case of a full-color PDP, full-color display can be performed by arranging the cells each having a phosphor film that emits red, blue, and green light by VUV excitation in a stripe shape or a matrix shape.
[0005]
The phosphor for forming the fluorescent film of these VUV excitation light emitting elements is (Y, Gd) BO₃: Red light-emitting phosphor such as Eu, LaPO₄: Ce, Tb, (Ba, Sr) MgAl₁₀O₁₇: Eu, Mn, Zn₂SiO₄: Green light-emitting phosphor such as Mn, BaMgAl₁₀O₁₇: Blue light-emitting phosphors such as Eu are used alone or in combination depending on the desired emission color. (See Electronic Materials Magazine December 1997 Issue, Industrial Research Company, etc.). Among these practical phosphors for VUV, which are practically used as a fluorescent film of a VUV excitation light emitting device, the phosphor mainly used as a blue component is BaMgAl.₁₀O₁₇: An aluminate phosphor having a composition of Eu and abbreviated as BAM, which has a high emission luminance when excited by irradiation with VUV and has a color purity of blue. Although good, the VUV-excited light-emitting device using this phosphor has a large luminance deterioration (baking deterioration) in a baking step when forming a fluorescent film, and the VUV-excited light-emitting device is driven to be exposed to VUV for a long time. There is a drawback that the emission luminance decreases significantly (VUV deterioration) over time when the light emission is performed, and it is desired to develop a blue-emitting VUV excitation phosphor with less baking deterioration and VUV deterioration.
[0006]
As a remedy for such a problem, one of blue-emitting phosphors having relatively little baking deterioration and VUV deterioration is to use Eu as an activator and its composition formula is CaMgSi.₂O₆: A divalent metal silicate phosphor represented by Eu has been reported (see Procedures of The 8th International Display Workshops 2001 pp. 1115). However, this phosphor has a problem that its luminance is lower than that of BAM, which is a conventional blue phosphor, and improvement of the luminance to a practical level has been studied.
[0007]
Looking at the method for producing a phosphor having a large influence on such quality, the phosphor used in this phosphor is CaCO 2₃And MgCO as a raw material of Mg₃And MgCO₃・ 2Mg (OH)₂And SiO as a raw material of Si₂And Eu as a raw material of Eu₂O₃Is introduced as a general method. However, on the other hand, a composition formula CaMgSi having a satisfactory emission intensity as a blue phosphor even when these materials are prepared and fired.₂O₆: It is known that a divalent metal silicate phosphor represented by Eu cannot be produced.
[0008]
On the other hand, as another method for producing this divalent metal silicate phosphor, Eu is used.₂O₃EuF instead of₃Is reported, and it has been reported that a phosphor having good color purity and relatively strong blue emission can be obtained.
However, in order to form a uniform and dense fluorescent film on a VUV-excited light emitting device such as a rare gas lamp or a PDP without practical problems, it is necessary to give the phosphor particles appropriate powder characteristics. In particular, the particle size measured by the Coulter counter method is 10 μm or less, preferably about 1 to 7 μm, and more preferably about 1 to 4 μm. Further, regarding the particle size distribution, σlog (L) And σlog (S) are desirably 0.5 or less. In the conventionally known manufacturing method using EuF3, the particle size of the obtained phosphor particles is too large, and a powder having a range of powder characteristics suitable for forming a phosphor film as described above has not been obtained. Is the current situation.
[0009]
Further, in the case of this phosphor, although the degree of baking deterioration and VUV deterioration is relatively small, BAM (BaMgAl) which is a conventional blue phosphor is used.₁₀O₁₇: Eu) is also a problem.
[0010]
Further, it is known that in an AC type PDP, the discharge starting voltage is affected by the tendency of the applied phosphor to be charged and changes. For example, BAM or (Y, Gd) BO₃: Zn in Eu has a low firing voltage and is easily negatively charged₂SiO₄: High in Mn. From the viewpoint of the circuit, it is desirable that the discharge starting voltage is low. CaMgSi manufactured by conventional manufacturing method₂O₆: Eu is easily negatively charged and requires a high pressure to start discharge. This is also CaMgSi₂O₆: Eu was one reason that PDP was not put into practical use. The charging tendency mentioned here can be evaluated by measuring the blow-off charge amount of the substance. Specifically, the phosphor powder and the Poval resin beads were mixed and shaken to generate triboelectric charging, and the charge amount of the phosphor powder was evaluated by measuring the blow-off charge amount.
[0011]
[Problems to be solved by the invention]
The present invention has been made in view of the above situation, and has a powder characteristic (grain size characteristic) that has a higher emission luminance than conventional ones and is preferable for forming a fluorescent film of a VUV excitation light emitting element such as a rare gas lamp or a PDP. It is an object of the present invention to provide a blue-emitting divalent metal silicate phosphor having a small particle size, a method for producing the same, a phosphor paste composition using the improved phosphor, and a VUV-excited light emitting device.
[0012]
[Means for Solving the Problems]
The present inventors have proposed the composition formula CaMgSi₂O₆: Various investigations were made on silicate phosphors containing Eu as an activator represented by Eu, and when a specific amount of chlorine was contained in the matrix of a conventional Eu-activated divalent metal silicate phosphor, or In the step of firing the phosphor raw material at least once at 800 ° C. or higher, when a Eu-activated divalent metal silicate phosphor is produced by incorporating a chlorine compound or chlorine into the phosphor raw material, the phosphor under VUV excitation It has been found that the light emission luminance is improved. Further, the above-mentioned improved specification makes it possible to produce a phosphor having a relatively small particle diameter suitable for forming a VUV-excited light-emitting device fluorescent film, which was not possible with the conventional specification, and furthermore, the weight median particle diameter of the phosphor particles. When D50 is 7 μm or less and σlog (L) and σlog (S) are controlled to 0.5 or less, surprisingly, it is possible to obtain a phosphor whose charging tendency by blow-off tends to be positively charged. I was able to find out.
[0013]
Further, by using the phosphor paste composition using the improved phosphor, it becomes possible to form a phosphor film on the VUV excitation light emitting device, and the VUV excitation light emitting device with improved blue component luminance I found that.
The present inventors have proposed that this CaMgSi₂O₆: With respect to the phosphor represented by Eu, various specifications for improvement were found as described above, and the present invention was reached.
That is, the above object of the present invention is achieved by adopting the following configuration.
[0014]
(1) The basic composition is represented by the general formula (Ca_1-x-uEu_xM^II _u) O ・ a (Mg_1-vZn_v) O.bSiO₂・ WM^IIIAnd a chlorine-containing divalent metal silicate phosphor.
｛However, in the above formula, M^IIRepresents at least one metal element among barium (Ba) and strontium (Sr);^IIIRepresents at least one metal element among lanthanum (La), yttrium (Y), cerium (Ce), indium (In) and bismuth (Bi), and a, b, x, u, v and w each represent 0.9 ≦ a ≦ 1.1, 1.9 ≦ b ≦ 2.2, 5 × 10^-3≦ x ≦ 10^-1And 0 ≦ u + v + w ≦ 4 × 10^-1Represents a number that satisfies the following condition: ｝
(2) The divalent metal silicate phosphor according to (1), wherein the amount of chlorine contained in the phosphor is 20,000 ppm or less.
[0015]
(3) The divalent metal silicate phosphor according to (1) or (2), wherein the weight median particle diameter D50 measured by the Coulter counter method is in the range of 1 to 7 μm.
(4) The divalent metal silicate phosphor according to (3), wherein the weight median particle diameter D50 measured by the Coulter counter method is in the range of 1 to 4 μm.
(5) The divalent metal silicate phosphor according to (3) or (4), wherein σlog (L) and σlog (S) measured by the Coulter counter method are 0.5 or less.
[0016]
(6) The divalent metal silicate phosphor according to any one of (1) to (5), wherein the blow-off charge relative to the Poval resin is positive.
(7) In the method for producing a divalent metal silicate phosphor, the phosphor raw material contains a chlorine compound or chlorine in the step of firing the phosphor raw material at least once at 800 ° C. or more. The method for producing a divalent metal silicate phosphor according to any one of the above (1) to (6).
(8) The method for producing a divalent metal silicate phosphor according to (7), wherein the amount of chlorine contained in the phosphor raw material is 0.001 wt% or more.
(9) The method for producing a divalent metal silicate phosphor according to (7) or (8), wherein ammonium chloride is used as the chlorine compound contained in the phosphor material.
[0017]
(10) In a phosphor paste composition obtained by dispersing a phosphor in a solvent in which a binder is dissolved, the phosphor is a divalent metal silicate phosphor according to any one of (1) to (6). Or a divalent metal silicate phosphor produced by the production method according to any one of (7) to (9).
(11) An ultraviolet-excitation light-emitting element that excites and emits the fluorescent film by vacuum ultraviolet rays emitted by discharge of a rare gas sealed in the envelope in which the fluorescent film is formed, wherein the fluorescent film is The divalent metal silicate phosphor according to any one of (1) to (6) or the divalent metal silicate phosphor produced by the production method according to any one of (7) to (9) A VUV-excited light emitting device characterized by being formed by:
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
To produce the phosphor of the present invention, stoichiometrically (Ca_1-x-uEu_xM^II _u) O ・ a (Mg_1-vZn_v) O.bSiO₂・ WM^III｛However, in the above formula, M^IIRepresents at least one metal element of Ba and Sr;^IIIRepresents at least one metal element among La, Y, Ce, In and Bi, and a, b, w, x, u and v are respectively 0.9 ≦ a ≦ 1.1, 1.9 ≦ b ≦ 2.2, 5 × 10^-3≦ x ≦ 10^-1And 0 ≦ u + v + w ≦ 4 × 10^-1Represents a number that satisfies the following condition: Hereinafter, the same applies. 、, Ca, Mg, Si, Eu, Zn and M^II, M^IIIA phosphor raw material mixture comprising a compound of each metal such as an oxide of each metal element represented by or a carbonate or a sulfate which can be converted into an oxide of each of the above metals at a high temperature into a heat-resistant container such as an alumina crucible. Then, firing is performed at least once in a reducing atmosphere at a temperature of 800 ° C. or more, preferably 1000 to 1400 ° C., for 2 to 40 hours. In the step of firing the phosphor material at least once at 800 ° C. or more, a chlorine compound or chlorine is contained in the phosphor material.
Thereafter, the fired product may be further subjected to post-treatments such as dispersion, washing, drying, and sieving according to the necessity such as the performance of the finally used phosphor in forming a phosphor film.
[0019]
In the step of firing the phosphor material at least once at 800 ° C. or more, the Eu-activated divalent metal silicate phosphor produced by the production method of the present invention in which a chlorine compound or chlorine is contained in the phosphor material is used. The conventional Eu-activated divalent metal silicate phosphor has a higher emission luminance under VUV excitation than the conventional Eu-activated divalent metal silicate phosphor, and has a weight median particle diameter D50 of 1 to 6 μm. It was found that the particle size was smaller than that.
[0020]
In the production of the phosphor of the present invention, as a chlorine supply source to be contained in the phosphor raw material, for example, an alkali metal chloride such as LiCl, NaCl, and KCl as a chlorine compound;₂, MgCl₂There is an alkaline earth metal chloride such as that described above. However, the alkali metal chloride is likely to cause fusion-aggregated particles of the phosphor particles which are completed after firing. On the other hand, the alkaline earth chloride contains a metal constituting the phosphor matrix, and has an effect on the matrix composition.
As a material which does not have such a disadvantage and is less affected by an alkaline substance during firing, ammonium chloride @ NH₄Cl is preferred. In addition, when ammonium chloride is used, a desired phosphor having a relatively small particle size and a small amount of coagulated particles can be obtained, which is necessary for forming a dense fluorescent film of a VUV excitation light emitting device such as a rare gas lamp or a PDP. Suitable powder characteristics, specifically, small particles having a particle size of 10 μm or less, preferably about 1 to 7 μm, more preferably about 1 to 4 μm, as measured by the Coulter counter method. σlog (L) and σlog (S) of 0.5 or less can be obtained.
[0021]
Further, the amount of chlorine contained in the phosphor raw material must be 0.001 wt% or more, which is the minimum amount that the effect of the present invention exerts on the crystal of the fluorescent particles. The preferred specific content is also affected by the type of chloride compound used.
[0022]
In the production of the phosphor of the present invention, apart from the effect of containing chlorine, which is the object of the present invention, the quality of the composition of the basic phosphor greatly affects the quality. It is necessary to consider enough.
Further, in the divalent metal silicate phosphor of the present invention, as the a value and the b value representing the composition of the host crystal deviate from 1.0 and 2.0, respectively, an incompletely crystallized phosphor or heterophase is formed. Since the probability of light emission increases and the emission luminance gradually decreases, the values a and b are 0.9 ≦ a ≦ 1.1 and 1.9 ≦ b ≦ 2 in terms of the emission luminance of the obtained phosphor. It is preferable that the number satisfies the range of 2, and it is particularly preferable that the a value and the b value are a = 1.0 and b = 2.0, respectively. Regarding the above-mentioned x value representing the activation amount of Eu, when this value exceeds 0.1, a different phase different from the above-mentioned composition is formed, the luminance of the phosphor is reduced, and 5 × 10^-3If it is smaller than this, the amount of the luminescent center becomes insufficient, and the luminescent intensity of the obtained phosphor is lowered, so that both are not preferable.
Therefore, the activation amount (x value) of Eu is 5 × 10 5 from the viewpoint of the emission luminance of the obtained phosphor.^-3≦ x ≦ 1 × 10^-1Is preferably a number that satisfies the range. The metal element M^II, Zn and metal element M^IIIThe total amount of the content (u + v + w) is 4 × 10^-1More than M^II, Zn and M^IIIIt is not preferable because the emission luminance is lower than that of a phosphor containing no chromium. Therefore, the metal element M^II, Zn and metal element M^IIIIs 0 ≦ (u + v + w) ≦ 4 × 10^-1Is preferably a number that satisfies the range.
[0023]
The phosphor paste composition of the present invention is obtained by adding the above-described divalent metal silicate phosphor of the present invention to a solvent in which the binder resin is dissolved, kneading the mixture sufficiently, and adjusting the amount of the solvent to thereby form the phosphor paste composition. It can be manufactured by forming a paste having an appropriate viscosity according to the use. Ethyl cellulose, nitrocellulose, polyethylene oxide, acrylic resin and the like are used as a binder resin when producing the phosphor paste composition containing the phosphor of the present invention, and also used for adjusting the viscosity of the paste. As the solvent, a solvent such as water, butyl acetate, butyl carbitol, and terpineol is used. Further, as the phosphor in the phosphor paste composition of the present invention, a mixed phosphor of the divalent metal silicate phosphor of the present invention and a phosphor of other composition may be used depending on the purpose and application. It goes without saying that it is good.
[0024]
Further, the VUV-excited light-emitting device of the present invention is obtained by applying the phosphor paste composition of the present invention to a predetermined location in an envelope made of glass or the like, drying the applied paste, and baking to form a phosphor film. It is manufactured in the same manner as the conventional VUV-excited light emitting device except that a phosphor film made of the divalent metal silicate phosphor of the present invention is formed.
The divalent metal silicate phosphor of the present invention thus obtained has a smaller particle diameter than the conventional divalent metal silicate phosphor and is improved. Thus, the use as a phosphor for a VUV-excited light-emitting device, which was difficult to form a fluorescent film due to a too large sphere diameter, became possible. Further, the divalent metal silicate phosphor of the present invention has higher emission luminance than the conventional divalent metal silicate phosphor, and furthermore, a phosphor film formed of a phosphor paste composition using this phosphor is used. As for the VUV-excited light-emitting device having the same, it is possible to obtain a device having higher luminance than the conventional device.
[0025]
【Example】
Next, the present invention will be described with reference to examples.
[Example 1A]
CaCO₃{0.98} mol
MgCO₃{1.0} mol
SiO₂{2.0} mol
Eu₂O₃{0.01} mol
NH₄Cl 0.2 mol
After sufficiently mixing the phosphor material in the above ratio containing 2.2 wt% of chlorine, 300 g is filled in an alumina crucible and fired in a reducing atmosphere at a maximum temperature of 1150 ° C. for 14 hours including a temperature rise / fall time. did. This baked product is subjected to a sieving process, and the composition formula is (Ca_0.98Eu_0.02) O ・ MgO ・ 2SiO₂Thus, the Eu-activated divalent metal silicate phosphor of Example 1A containing 13,000 ppm of chlorine and having a positive charge of a blow-off charge of 1.8 μC / g relative to the Poval resin was obtained.
[0026]
The chlorine content in the phosphor of the present invention was derived as follows. First, a solution in which the phosphor of the present invention is dissolved in boric acid and sodium carbonate is added to a mixed solution of 1% of silver nitrate, 50% of glycerin and 49% of pure water to precipitate silver chloride. The turbidity of the solution is measured with a spectrophotometer. The turbidity of this solution was determined by comparing the turbidity with a standard addition solution prepared by directly adding a predetermined amount of chlorine to a mixed solution of silver nitrate 1%, glycerin 50% and pure water 49%. Quantified.
[0027]
The thus-obtained phosphor powder of Example 1A was filled in a cell having a cylindrical recess having a diameter of 12 mm and a depth of 1 mm, and the cell was pressed down with a glass plate to form a flat powder. A phosphor screen is prepared, and the phosphor screen is irradiated with vacuum ultraviolet rays of 146 nm to excite and emit light, and the emission luminance and the chromaticity point of the emission color at that time are measured to derive a sum of stimulation (emission luminance / y value). As a result, the value was 116% with respect to 100% of the stimulus sum value of Comparative Example 1A, which was measured in the same manner.
Note that the luminance of the blue phosphor changes greatly in proportion to its emission color (y value of chromaticity coordinates according to the CIE color system), so that the luminous efficiency between the blue emission phosphors having different y values of the emission color is reduced. As a simple method of comparison, the emission color is compared by a value (luminance / y) obtained by dividing the luminance by the y value when expressed in chromaticity coordinates (x, y) (hereinafter referred to as “stimulus sum”). Is generally performed. Hereinafter, comparison of the luminous efficiency of the phosphor is performed based on the sum of the stimuli.
[0028]
When the particle size distribution of the phosphor of Example 1A was derived by the Coulter counter method, the weight median particle diameter (D50) was 3.9 μm, σlog (L) = 0.38, σlog (S) = 0.45. Met.
Here, Dn indicates the particle size of n% cumulative on a weight basis from the smaller particle size, and σlog (L) and σlog (S) are respectively σlog (L) = log (D84.1 / D50) and σlog (S) = − log (D15.9 / D50). σlog (L) is a value indicating a particle size distribution of a larger particle size than D50, and σlog (S) is a value indicating a particle size distribution of a smaller particle size than D50. It indicates that it is big.
[0029]
[Example 1B]
30% by weight of Eu activated divalent metal silicate phosphor of Example 1A, 10% by weight of butyl carbitol, 53% by weight of butyl carbitol acetate and 7% by weight of ethylcellulose were thoroughly kneaded. The phosphor paste composition of Example 1B was prepared.
[0030]
[Example 1C]
The phosphor paste composition of Example 1B obtained as described above is applied on a glass plate having a width of 2 mm, dried at 120 ° C. for 30 minutes, and then baked at 500 ° C. for 30 minutes, whereby the fluorescent light is applied on the glass plate. A film was formed. This glass plate was held in a glass tube having an outer diameter of 4 mm, nickel electrodes were attached to both ends of the glass tube, and the inside of the tube was evacuated to vacuum. Then, a gas of 98% Ne-Xe 2% was filled with 50 torr, and Example 1C VUV-excited light-emitting device (rare gas lamp) was manufactured. The phosphor film formed by the phosphor paste composition of Example 1B is the same as the conventional chlorine-free phosphor CaMgSi.₂O₆Was visually confirmed to be dense and non-uniform unlike a phosphor film having a too large sphere diameter and a coarse phosphor film. Further, the VUV-excited light emitting device of Example 1C could be used without any practical problem.
[0031]
[Example 2A]
CaCO₃{0.98} mol
MgCO₃{1.0} mol
SiO₂{2.0} mol
Eu₂O₃{0.01} mol
NH₄Cl 0.2 mol
After sufficiently mixing the phosphor material in the above ratio containing 2.2 wt% of chlorine, 16 g was filled in an alumina crucible, and the composition formula was changed to (Ca) in the same manner as in Example 1A._0.98Eu_0.02) O ・ MgO ・ 2SiO₂Thus, the Eu-activated divalent metal silicate phosphor of Example 2A containing 200 ppm of chlorine and having a positive charge of 14.1 μC / g relative to the poval resin was obtained.
[0032]
When the phosphor of Example 2A was excited by 146 nm vacuum ultraviolet rays to emit light in the same manner as in Example 1A, the emission luminance and the chromaticity point of the emission color were measured. The value was 132% with respect to 100% of the stimulus sum value of Comparative Example 1A below.
When the particle size distribution of the phosphor of Example 2A was derived by the Coulter counter method, the weight median particle diameter (D50) was 6.0 μm, σlog (L) = 0.43, σlog (S) = 0.43. Met.
[0033]
[Example 2B]
A paste composition of Example 2B was produced in the same manner as the phosphor paste composition of Example 1B except that the phosphor of Example 2A was used instead of the phosphor of Example 1A.
[0034]
[Example 2C]
A VUV excitation light-emitting device of Example 2C was obtained in the same manner as in Example 1C, except that the phosphor paste composition of Example 2B was used instead of the phosphor paste composition of Example 1B. It was visually confirmed that the phosphor film formed of the phosphor paste composition of Example 2B was dense and uniform, and the VUV-excited light-emitting device of Example 2C could be used without any practical problem. .
[0035]
[Comparative Example 1A]
CaCO₃{0.98} mol
MgCO₃{1.0} mol
SiO₂{2.0} mol
EuF₃{0.02} mol
After sufficiently mixing the phosphor material in the above ratio not containing chlorine, 16 g was charged into an alumina crucible, and the composition formula was changed to (Ca) in the same manner as in Example 1A._0.98Eu_0.02) O ・ MgO ・ 2SiO₂Thus, the Eu-activated divalent metal silicate phosphor of Comparative Example 1A containing no chlorine and having a negative charge of -13.6 μC / g relative to the poval resin was obtained.
[0036]
In the same manner as in Example 1A, the phosphor of Comparative Example 1A was excited with vacuum ultraviolet rays of 146 nm to emit light, and the luminous luminance and the chromaticity point of the luminescent color were measured to obtain the stimulus sum. 100% was used as the standard for the sum of stimulation.
When the particle size distribution of the phosphor of Comparative Example 1A was derived by the Coulter counter method, the weight median particle size (D50) was 8.5 μm, σlog (L) = 0.59, σlog (S) = 0.66. And did not reach the desired properties.
[0037]
[Comparative Example 1B]
A paste composition of Comparative Example 1B was produced in the same manner as the phosphor paste composition of Example 1B, except that the phosphor of Comparative Example 1A was used instead of the phosphor of Example 1A.
[0038]
[Comparative Example 1C]
A VUV-excited light-emitting device of Comparative Example 1C was obtained in the same manner as the VUV-excited light-emitting device of Example 1C, except that the phosphor paste composition of Comparative Example 1B was used instead of the phosphor paste composition of Example 1B. Since the phosphor film formed of the phosphor paste composition of Comparative Example 1B had many pinholes, unevenness, and peeling points, the VUV-excited light emitting device of Comparative Example 1C was not practical.
[0039]
[Comparative Example 2A]
CaCO₃{0.98} mol
MgCO₃{1.0} mol
SiO₂{2.0} mol
Eu₂O₃{0.01} mol
After sufficiently mixing the phosphor material in the above ratio not containing chlorine, 16 g was charged into an alumina crucible, and the composition formula was changed to (Ca) in the same manner as in Example 1A._0.98Eu_0.02) O ・ MgO ・ 2SiO₂Thus, the Eu-activated divalent metal silicate phosphor of Comparative Example 2A containing no chlorine and having a negative charge of -9.6 μC / g relative to the Poval resin was obtained.
[0040]
When the phosphor of Comparative Example 2A was excited by 146 nm vacuum ultraviolet rays to emit light in the same manner as in Example 1A, the emission luminance and the chromaticity point of the emission color were measured. The value was 9% with respect to 100% of the stimulus sum value of Comparative Example 1A.
When the particle size distribution of the phosphor of Comparative Example 2A was derived by the Coulter counter method, the weight median particle size (D50) was 41.4 μm, σlog (L) = 0.53, σlog (S) = 1.09. The particle size was very large and the particle size distribution was very wide.
Since the phosphor of Comparative Example 2A had a very low emission intensity, it was not satisfactory for use as a phosphor.
[0041]
[Example 3A]
CaCO₃{0.98} mol
MgCO₃{1.0} mol
SiO₂{2.0} mol
Eu₂O₃{0.01} mol
NH₄Cl 0.2 mol
After sufficiently mixing the phosphor material in the above ratio containing 2.2 wt% of chlorine, 300 g is filled in an alumina crucible and fired in a reducing atmosphere at a maximum temperature of 1150 ° C. for 14 hours including a temperature rise / fall time. did. After sieving the calcined product, 200 g of the calcined product was mixed with 400 g of pure water and 400 g of 5φ alumina balls in a glass pot having a capacity of 1000 ml, mixed, and subjected to a wet ball mill at a rotation speed of 19.1 Hz for 16 hours. Was. After this dispersion treatment, drying and sieving treatments are performed, and the composition formula becomes (Ca_0.98Eu_0.02) O ・ MgO ・ 2SiO₂Thus, the Eu-activated divalent metal silicate phosphor of Example 3A containing 760 ppm of chlorine and having a positive charge of 30.9 μC / g relative to the poval resin was obtained.
[0042]
When the phosphor of Example 3A was excited by 146 nm vacuum ultraviolet rays to emit light in the same manner as in Example 1A, the emission luminance and the chromaticity point of the emission color were measured. The value was 104% with respect to the stimulus sum value of 100% in Comparative Example 1A.
When the particle size distribution of the phosphor of Example 3A was derived by the Coulter counter method, the weight median particle diameter (D50) was 2.9 μm, σlog (L) = 0.27, σlog (S) = 0.30. Met.
[0043]
[Example 3B]
A paste composition of Example 3B was produced in the same manner as the phosphor paste composition of Example 1B, except that the phosphor of Example 3A was used instead of the phosphor of Example 1A.
[0044]
[Example 3C]
A VUV-excited light-emitting device of Example 3C was obtained in the same manner as in Example 1C, except that the phosphor paste composition of Example 3B was used instead of the phosphor paste composition of Example 1B. It was visually confirmed that the phosphor film formed of the phosphor paste composition of Example 3B was dense and uniform, and the VUV-excited light emitting device of Example 3C could be used without any practical problem. .
[0045]
[Comparative Example 4A]
CaCO₃{0.98} mol
MgCO₃{1.0} mol
SiO₂{2.0} mol
Eu₂O₃{0.01} mol
NH₄HF₂{0.05} mol
After sufficient mixing of the phosphor raw materials in the above ratio not containing chlorine, the composition formula was changed to (Ca) in the same manner as in Example 3A._0.98Eu_0.02) O ・ MgO ・ 2SiO₂Thus, the Eu-activated divalent metal silicate phosphor of Comparative Example 4A containing no chlorine and having a negative charge of -10.4 μC / g relative to the poval resin was obtained.
[0046]
When the phosphor of Comparative Example 4A was excited with 146 nm vacuum ultraviolet rays to emit light in the same manner as in Example 1A, the emission luminance and the chromaticity point of the emission color were measured, and the sum of the stimuli was determined. The value was 98% with respect to the stimulus sum value of 100% in Comparative Example 1A.
When the particle size distribution of the phosphor of Comparative Example 4A was derived by the Coulter counter method, the weight median particle diameter (D50) was 7.7 μm, σlog (L) = 0.37, σlog (S) = 0.56. Met.
[0047]
[Comparative Example 4B]
A paste composition of Comparative Example 4B was produced in the same manner as the phosphor paste composition of Example 1B except that the phosphor of Comparative Example 4A was used instead of the phosphor of Example 1A.
[0048]
[Comparative Example 4C]
A VUV-excited light-emitting device of Comparative Example 4C was obtained in the same manner as the VUV-excited light-emitting device of Example 1C, except that the phosphor paste composition of Comparative Example 4B was used instead of the phosphor paste composition of Example 1B. Since the phosphor film formed of the phosphor paste composition of Comparative Example 4B had many pinholes, unevenness, and peeling portions, the VUV excitation light emitting device of Comparative Example 4C was not practical.
[0049]
【The invention's effect】
According to the present invention, by adopting the above configuration, the emission luminance is improved as compared with the conventional Eu-activated divalent metal silicate phosphor, and a phosphor having a small particle size can be provided. This phosphor is used as a phosphor film. By using this, it has become possible to provide a VUV-excited light-emitting element having high emission luminance.

Claims (11)

The basic composition is represented by the general formula (Ca _1-x- Eu _x M ^II _u ) Oa (Mg _1-v Znv) ObSiO ₂ wM ^III and contains chlorine. Divalent metal silicate phosphor.
In the above formula, M ^II represents at least one metal element among barium (Ba) and strontium (Sr), and M ^III represents lanthanum (La), yttrium (Y), cerium (Ce), indium. (In) and at least one metal element in bismuth (Bi), wherein a, b, x, u, v and w are 0.9 ≦ a ≦ 1.1 and 1.9 ≦ b ≦ 2, respectively. .2, 5 × 10 ⁻³ ≦ x ≦ 10 ⁻¹ and 0 ≦ u + v + w ≦ 4 × 10 ⁻¹ . ｝ 2. The divalent metal silicate phosphor according to claim 1, wherein the amount of chlorine contained in the phosphor is 20,000 ppm or less. The divalent metal silicate phosphor according to claim 1 or 2, wherein the phosphor has a weight median particle diameter D50 measured by a Coulter counter method within a range of 1 to 7 µm. 4. The divalent metal silicate phosphor according to claim 3, wherein a weight median particle diameter D50 measured by a Coulter counter method is in a range of 1 to 4 [mu] m. 5. The divalent metal silicate phosphor according to claim 3, wherein σlog (L) and σlog (S) are 0.5 or less in a particle size distribution measured by a Coulter counter method. The bivalent metal silicate phosphor according to any one of claims 1 to 5, wherein the amount of blow-off charge relative to the Poval resin is positive. The method for producing a divalent metal silicate phosphor, wherein the phosphor raw material contains a chlorine compound or chlorine in the step of firing the phosphor raw material at least once at 800 ° C. or higher. 7. The method for producing a divalent metal silicate phosphor according to any one of 6. The method for producing a divalent metal silicate phosphor according to claim 7, wherein the amount of chlorine contained in the phosphor raw material is 0.001 wt% or more. 10. The method for producing a divalent metal silicate phosphor according to claim 8, wherein ammonium chloride is used as the chlorine compound contained in the phosphor raw material. In a phosphor paste composition obtained by dispersing a phosphor in a solvent in which a binder is dissolved, the phosphor is the divalent metal silicate phosphor according to any one of claims 1 to 6, or A phosphor paste composition, which is a divalent metal silicate phosphor produced by the production method according to any one of claims 7 to 9. 2. An ultraviolet-excitation light-emitting element that excites and emits a fluorescent film by vacuum ultraviolet rays emitted by discharge of a rare gas sealed in an envelope on which the fluorescent film is formed, wherein the fluorescent film is formed. 10. The divalent metal silicate phosphor according to any one of claims 6 to 6 or the divalent metal silicate phosphor produced by the production method according to any one of claims 7 to 9. Characteristic vacuum ultraviolet light excitation light emitting element.