JP5385961B2 - Phosphor and light emitting device using the same - Google Patents

Description

  The present invention relates to a phosphor.

  The phosphor is used in a light emitting device or the like in which a phosphor excitation source represented by a white LED or the like is light in the ultraviolet to blue region.

A phosphor that emits light by being excited by light in the ultraviolet to blue region is already known. For example, as a phosphor for a white LED, a phosphor represented by the formula Y ₃ Al ₅ O ₁₂ : Ce (see Patent Document 1). ), A phosphor represented by the formula Li ₂ SrSiO ₄ : Eu (see Patent Document 2), and the like are known.

Japanese Patent Laid-Open No. 10-242513 International Publication No. 03/80763 Pamphlet

  However, it cannot be said that these phosphors are sufficient in light emission stability against light emission intensity and temperature change. An object of the present invention is to provide a phosphor that is practically less problematic in terms of light emission intensity and stability against temperature changes.

  As a result of intensive studies to solve the above problems, the present inventors have reached the present invention.

That is, the present invention provides the following phosphor and light emitting device.
<1> Represented by the formula Li ₂ (M ² _1−x Eu _x ) SiO ₄ , M ² is Sr and Ca or Sr and Ba, and the value of x is 0.01 or more, 0.3 hereinafter der Ri, Sr, the ratio of the molar amount of Ca to the total molar amount of Ca and Eu, and Sr, the ratio of the molar amount of Ba to the total molar amount of Ba and Eu are both 0. Phosphors, characterized in that it contains the Ah Ru compound 1.
< 2 > The phosphor according to <1> , further comprising one or more elements selected from the group consisting of F, Cl, Br and I, in a range of 50 ppm to 1000 ppm with respect to the weight of the phosphor.
< 3 > One or more elements selected from the group consisting of Sc, Y, La, Gd, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Bi as activators Any one of said fluorescent substance containing.
< 4 > A light emitting device comprising the phosphor according to any one of the above.
< 5 > A phosphor according to any one of <1> to < 3 >, wherein the phosphor is a light emitting device having a light emitting element and a phosphor that emits light by being excited by at least a part of light emitted from the light emitting element. A light emitting device.
< 6 > The light-emitting device according to < 5 >, wherein the wavelength of light emitted from the light-emitting element is 200 nm or more and 550 nm or less.

  The phosphor of the present invention exhibits high emission intensity, and further, there is little decrease in the emission intensity associated with temperature rise. Therefore, when the phosphor of the present invention is used in a light emitting device such as a white LED, it exhibits high emission intensity and temperature. Since it is possible to reduce the decrease in emission intensity accompanying the increase, it is extremely useful industrially.

The present invention is described in detail below.

The phosphor of the present invention has the formula (1)
aM ¹ ₂ O · bM ² O · cM ³ O ₂ (1)
Eu is contained at least as an activator. M ^{1 in the} formula (1) is one or more elements selected from the group consisting of Li, Na, K, Rb and Cs, and M ² is 1 selected from the group consisting of Ca, Sr, Ba, Mg and Zn. It is an element of a seed or more, M ³ is Si and / or Ge, a is in the range of 0.1 to 1.5, b is in the range of 0.8 to 1.2, c Is in the range of 0.8 to 1.2. However, when a = b = c = 1, M ¹ = Li and M ³ = Si, M ² is not only Sr.

M ² in formula (1) is one or more elements selected from the group consisting of Ca, Ba, Mg and Zn, or two or more elements selected from the group consisting of Ca, Sr, Ba, Mg and Zn. preferable. Further, a is preferably in the range of 0.8 to 1.2.

In addition, the phosphor of the present invention is more preferably a phosphor containing the compound represented by the formula (2) because it exhibits higher emission intensity.
M ¹ ₂ (M ² _1-x Eu _x ) M ³ O ₄ (2)
M ^{1 in the} formula (2) is one or more elements selected from the group consisting of Li, Na, K, Rb and Cs, and M ² is one type selected from the group consisting of Ca, Ba, Mg and Zn or Two or more elements selected from the group consisting of Ca, Sr, Ba, Mg and Zn, M ³ is Si and / or Ge, and the value of x is in the range of more than 0 and 1 or less.

Here, M ¹ is more preferably one or more elements selected from the group consisting of Li, Na and K, and most preferably Li. M ² is more preferably one or more elements composed of Ca and Sr, and most preferably Ca and Sr. M ³ is more preferably Si. By using M ¹ , M ² , and M ³ as described above, the white LED of the present invention exhibits higher emission intensity. Here, x is preferably in the range of 0.001 to 0.5, and more preferably in the range of 0.01 to 0.3. By setting x in the above range, the white LED of the present invention exhibits higher emission intensity.

  The phosphor of the present invention may contain an activator other than Eu as the second activator. Examples of the activator other than Eu include one selected from the group consisting of Sc, Y, La, Gd, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Bi. The above elements are mentioned.

  In addition, since the phosphor of the present invention exhibits high emission intensity, it is preferable that one or more elements selected from the group consisting of F, Cl, Br and I are contained in an amount of 30 ppm to 10,000 ppm with respect to the phosphor weight. More preferably, it is 50 ppm or more and 1000 ppm or less. By including at least one element selected from the group consisting of F, Cl, Br and I as described above, the white LED of the present invention exhibits higher emission intensity.

  Next, a method for producing the phosphor of the present invention will be described.

The phosphor of the present invention can be manufactured, for example, as follows. The phosphor of the present invention can be produced by firing a metal compound mixture that becomes the phosphor of the present invention by firing. That is, it can be produced by firing a metal compound mixture obtained after weighing and mixing a compound containing a corresponding metal element to have a predetermined composition. For example, a phosphor composed of a compound represented by the formula Li ₂ (Sr _0.88 Ca _0.1 Eu _0.02 ) SiO ₄ , which is one of the preferred compositions, is Li ₂ CO ₃ , SrCO ₃ , CaCO ₃ , Eu ₂ O ₃ , SiO _{2. 2} is weighed so that the molar ratio of Li: Sr: Ca: Eu: Si is 2.0: 0.88: 0.1: 0.02: 1.0, mixed and then fired. be able to.

  Examples of the compound containing the metal element include lithium, sodium, potassium, rubidium, cesium, calcium, strontium, barium, magnesium, zinc, silicon, germanium, scandium, yttrium, lanthanum, gadolinium, lutetium, cerium, praseodymium, neodymium. , Samarium, europium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, manganese, bismuth compounds, for example using oxides or high temperatures such as hydroxides, carbonates, nitrates, halides, oxalates Those that can be decomposed and / or oxidized into oxides can be used.

  For the mixing of the compound containing the metal element, for example, a generally industrially used apparatus such as a ball mill, a V-type mixer or a stirrer can be used. Also, either wet mixing or dry mixing may be used.

  The phosphor of the present invention can be obtained by firing the metal compound mixture while maintaining it in a temperature range of, for example, 700 ° C. to 1600 ° C. for 1 to 100 hours. If the metal compound mixture contains hydroxides, carbonates, nitrates, halides, oxalates, etc. that can be decomposed and / or oxidized to form oxides at high temperatures, before firing, the metal compound mixture It is possible to obtain an oxide or remove crystal water by, for example, maintaining the material at a temperature lower than the firing temperature and calcining. Moreover, it can also grind | pulverize after calcination.

The atmosphere during firing is an inert gas atmosphere such as nitrogen or argon, an oxidizing atmosphere such as air, oxygen, oxygen-containing nitrogen, oxygen-containing argon, hydrogen-containing nitrogen containing 0.1 to 10% by volume of hydrogen, hydrogen And reducing atmospheres such as hydrogen-containing argon containing 0.1 to 10% by volume. When firing in a strong reducing atmosphere, an appropriate amount of carbon may be added to the metal compound mixture and fired. In addition, if an appropriate amount of a reaction accelerator is present in the metal compound mixture during firing or calcination in order to enhance the crystallinity of the obtained phosphor, the phosphor may exhibit high emission intensity. Examples of the reaction accelerator include LiF, NaF, KF, LiCl, NaCl, KCl, Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , NaHCO ₃ , NH ₄ Cl, NH ₄ I, and the like. it can.

  The phosphor obtained by the above method can be pulverized using, for example, a ball mill or a jet mill. It can also be washed and classified. Moreover, baking can also be performed twice or more.

In addition, as an example of a light emitting device using the phosphor of the present invention, a white LED will be described and a manufacturing method thereof will be described. As a manufacturing method of the white LED, for example, it can be manufactured by a known method as disclosed in JP-A-11-31845, JP-A-2002-226846, and the like. A white LED can be manufactured by sealing a light-emitting element that emits light having a wavelength of 200 nm or more and 550 nm or less with a light-transmitting resin such as an epoxy resin and arranging a phosphor so as to cover the surface thereof. In this case, the phosphor amount is appropriately set so as to emit light in a desired white color. Moreover, the phosphor of the present invention can be used alone or in combination with other phosphors. Other phosphors include BaMgAl ₁₀ O ₁₇ : Eu, (Ba, Sr, Ca) (Al, Ga) ₂ S ₄ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, Mn, BaAl ₁₂ O ₁₉ : Eu, Mn, (Ba, Sr, Ca) S: Eu, Mn, YBO ₃ : Ce, Tb, Y ₂ O ₃ : Eu, Y ₂ O ₂ S: Eu, YVO ₄ : Eu, (Ca, Sr) S: Eu, SrY ₂ O ₄ : Eu, Ca—Al—Si—O—N: Eu and Li— (Ca, Mg) —Ln—Al—O—N: Eu (where Ln represents a rare earth metal element other than Eu), etc. Is mentioned. Examples of the light emitting element that emits light having a wavelength of 200 nm or more and 550 nm or less include an ultraviolet LED and a blue LED. These include GaN, In _i Ga _1-i N (0 <i <1), A semiconductor having a layer such as In _i Al _j Ga _1-ij N (0 <i <1, 0 <j <1, i + j <1) is used. The emission wavelength can be changed by changing the composition of the light emitting layer.

  In addition to the white LED described above, the phosphor of the present invention is represented by a light emitting device whose phosphor excitation source represented by PDP is a vacuum ultraviolet ray, a backlight for liquid crystal display, a three-wavelength fluorescent lamp, and the like. The phosphor excitation source can be preferably used for a light-emitting device in which ultraviolet light is used, and a light-emitting device in which the phosphor excitation source represented by CRT or FED is an electron beam.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
Measurement of the emission intensity of the phosphor was performed using a fluorescence spectrometer (SPEX Fluorog-3 manufactured by Joban Yvon).

Comparative Example 1
Yttrium oxide (Shin-Etsu Chemical Co., Ltd .: purity 99.99%), Gadolinium oxide (Shin-Etsu Chemical Co., Ltd .: purity 99.99%), Cerium oxide (Shin-Etsu Chemical Co., Ltd .: purity 99.99%) Each raw material of aluminum oxide (manufactured by Sumitomo Chemical Co., Ltd .: purity 99.99%) is adjusted so that the molar ratio of Y: Gd: Ce: Al is 1.71: 1.2: 0.09: 5.0. The slurry was weighed and mixed for 4 hours by a wet ball mill using isopropyl alcohol to obtain a slurry. The obtained slurry was dried by an evaporator, and the obtained metal compound mixture was fired by holding it in an air atmosphere at a temperature of 1600 ° C. for 24 hours, and then gradually cooled to room temperature, so that the composition formula was (Y _0.57 Gd _0.4 A phosphor 1 containing a compound represented by Ce _0.03 ) ₃ Al ₅ O ₁₂ was obtained.

  Emission intensity obtained by irradiating the phosphor 1 with light having a wavelength of 460 nm. When the intensity at room temperature (25 ° C.) is 100, 95 at 50 ° C., 88 at 75 ° C., 81 at 100 ° C., 78 at 120 ° C. there were.

Example 1
Lithium carbonate (manufactured by Kanto Chemical Co., Ltd., purity 99%), strontium carbonate (manufactured by Sakai Chemical Industry Co., Ltd., purity 99% or more), calcium carbonate (manufactured by Ube Materials Co., Ltd .: purity 99.9%), europium oxide ( Each raw material of Shin-Etsu Chemical Co., Ltd., purity 99.99%) and silicon dioxide (Nippon Aerosil Co., Ltd .: purity 99.99%) has a molar ratio of Li: Sr: Ca: Eu: Si of 2.0: 0.88: 0.1: 0.02: 1.0 was weighed and mixed by a wet ball mill using isopropyl alcohol for 4 hours to obtain a slurry. The obtained slurry was dried by an evaporator, and the obtained metal compound mixture was baked by being held in an air atmosphere at a temperature of 900 ° C. for 12 hours, and then gradually cooled to room temperature. Next, after pulverization with an agate mortar, the mixture was calcined in a N ₂ atmosphere containing 2% by volume of H ₂ at a temperature of 900 ° C. for 12 hours, and then gradually cooled to room temperature, so that the composition formula was Li ₂ (Sr _0.88 Ca _0.1 Eu). _0.02 ) A phosphor 2 containing a compound represented by SiO ₄ was obtained. The amount of fluorine contained in phosphor 2 was 8 ppm, the amount of chlorine was 15 ppm, the amount of bromine was 2 ppm, and the amount of iodine was 4 ppm.

  The emission intensity obtained by irradiating the phosphor 2 with light having a wavelength of 460 nm, where the intensity at room temperature (25 ° C.) is 100, 100 at 50 ° C., 100 at 75 ° C., 99 at 100 ° C., 97 at 120 ° C. there were.

Example 2
Lithium carbonate (manufactured by Kanto Chemical Co., Ltd., purity 99%), strontium carbonate (manufactured by Sakai Chemical Industry Co., Ltd., purity 99% or more), barium carbonate (manufactured by Nippon Chemical Industry Co., Ltd .: purity 99% or more), europium oxide (Shin-Etsu) Each raw material of Chemical Industries, Ltd. (purity: 99.99%) and silicon dioxide (Nippon Aerosil Co., Ltd .: purity: 99.99%) has a Li: Sr: Ba: Eu: Si molar ratio of 2.0: 0. .88: 0.1: 0.02: 1.0 The same procedure as in Example 1 was performed except that the weight was adjusted so that the composition formula was Li ₂ (Sr _0.88 Ba _0.1 Eu _0.02 ) SiO ₄ . A phosphor 3 containing the compound to be obtained was obtained. The amount of fluorine contained in the phosphor 3 was 7 ppm, the amount of chlorine was 11 ppm, the amount of bromine was 4 ppm, and the amount of iodine was 6 ppm.

  The emission intensity obtained by irradiating the phosphor 3 with light having a wavelength of 460 nm, where the intensity at room temperature (25 ° C.) is 100, 99 at 50 ° C., 98 at 75 ° C., 97 at 100 ° C., 95 at 120 ° C. there were.

Example 3
Lithium carbonate (manufactured by Kanto Chemical Co., Ltd., purity 99%), strontium carbonate (manufactured by Sakai Chemical Industry Co., Ltd., purity 99% or more), calcium carbonate (manufactured by Ube Materials Co., Ltd .: purity 99.9%), europium oxide ( Each material of Shin-Etsu Chemical Co., Ltd., purity 99.99%), silicon dioxide (Nippon Aerosil Co., Ltd .: purity 99.99%), ammonium chloride (Wako Pure Chemical Industries, Ltd .: purity 99%) is made of Li. : Sr: Ca: Eu: Si: Cl molar ratio is 2.0: 0.88: 0.1: 0.02: 1.0: 0.05, and wet using isopropyl alcohol The mixture was mixed by a ball mill for 4 hours to obtain a slurry. The obtained slurry was dried by an evaporator, and the obtained metal compound mixture was baked by being held in an air atmosphere at a temperature of 900 ° C. for 12 hours, and then gradually cooled to room temperature. Next, after pulverization with an agate mortar, it is fired by holding at a temperature of 900 ° C. for 12 hours in an N ₂ atmosphere containing 2% by volume of H ₂ , then gradually cooled to room temperature, further washed with pure water, and dried. compositional formula to obtain a phosphor 4 containing a compound represented by _{Li 2 (Sr 0.88 Ca 0.1 Eu} 0.02) SiO 4. The amount of chlorine contained in the phosphor 4 was 130 ppm.

  The emission intensity obtained by irradiating the phosphor 4 with light having a wavelength of 460 nm, where the intensity at room temperature (25 ° C.) is 100, 100 at 50 ° C., 100 at 75 ° C., 99 at 100 ° C., 97 at 120 ° C. there were.

Example 4
Lithium carbonate (manufactured by Kanto Chemical Co., Ltd., purity 99%), strontium carbonate (manufactured by Sakai Chemical Industry Co., Ltd., purity 99% or more), calcium carbonate (manufactured by Ube Materials Co., Ltd .: purity 99.9%), europium oxide ( Shin-Etsu Chemical Co., Ltd., purity 99.99%), silicon dioxide (Nippon Aerosil Co., Ltd .: purity 99.99%), lithium fluoride (High Purity Chemical Laboratory Co., Ltd .: purity 99% or more) The raw material was weighed so that the molar ratio of Li: Sr: Ca: Eu: Si: F was 2.0: 0.88: 0.1: 0.02: 1.0: 0.05 (however, The ratio of lithium carbonate to lithium fluoride was Li ₂ CO ₃ : LiF = 0.975: 0.05 in molar ratio.) The same operation as in Example 3 was performed, and the composition formula was Li ₂ (Sr _0.88 Ca _0.1 Eu _0.02 ) SiO ₄ The fluorescent substance 5 containing the compound represented by this was obtained. The amount of fluorine contained in the phosphor 5 was 270 ppm.

  The emission intensity obtained by irradiating the phosphor 5 with light having a wavelength of 460 nm, where the intensity at room temperature (25 ° C.) is 100, 101 at 50 ° C., 100 at 75 ° C., 99 at 100 ° C., 97 at 120 ° C. there were.

Comparative Example 2
Lithium carbonate (manufactured by Kanto Chemical Co., Inc., purity 99%), strontium carbonate (manufactured by Sakai Chemical Industry Co., Ltd., purity 99% or more), europium oxide (manufactured by Shin-Etsu Chemical Co., Ltd., purity 99.99%), silicon dioxide ( Except that each raw material of Nippon Aerosil Co., Ltd. (purity: 99.99%) was weighed so that the molar ratio of Li: Sr: Eu: Si was 2.0: 0.98: 0.02: 1.0 Then, the same operation as in Example 1 was performed to obtain a phosphor 6 containing a compound whose composition formula is represented by Li ₂ (Sr _0.98 Eu _0.02 ) SiO ₄ .

Example 5
Assuming that the emission intensity obtained by irradiating the phosphor 6 with light having a wavelength of 460 nm at room temperature (25 ° C.) is 100, the emission intensity of the phosphor 2 is 110, the emission intensity of the phosphor 3 is 107, and The emission intensity was 134, and the emission intensity of phosphor 5 was 121.

Example 6
When a blue LED having a light emitting layer made of In _0.3 Ga _0.7 N is manufactured and the light emitting device manufactured by applying the phosphor 4 so as to capture the blue LED so as to capture the blue LED is caused to emit light, White light was emitted by the color mixture of the light and the light emitted by the phosphor 4 being excited thereby.

Claims (6)

Formula Li ₂ (M ² _1-x Eu _x ) SiO ₄
Represented by
In the above formula, M ² is Sr and Ca or Sr and Ba,
The value of x is 0.01 or more state, and are 0.3 or less,
Sr, the ratio of the molar amount of Ca to the total molar amount of Ca and Eu, and Sr, the ratio of the molar amount of Ba to the total molar amount of Ba and Eu are that both containing 0.1 der Ru compounds A characteristic phosphor. Further F, Cl, phosphor according to claim 1 Symbol mounting one or more elements selected from the group consisting of Br and I containing 50ppm or 1000ppm or less based phosphor weight. Furthermore, Sc, Y, La, Gd, Ce, Pr, Nd, Sm, Tb, Dy, H as activators
The phosphor according to claim 1 or 2, comprising one or more elements selected from the group consisting of o, Er, Tm, Yb, Lu and Bi. The light emitting device characterized by comprising using a phosphor according to any one of claims 1-3. 4. A light emitting device having a light emitting element and a phosphor that emits light by being excited by at least a part of light emitted from the light emitting element, wherein the phosphor is the phosphor according to any one of claims 1 to 3 . The light emitting device according to claim 5 , wherein the wavelength of light emitted from the light emitting element is 200 nm or more and 550 nm or less.