JP4171890B2 - Red light emitting phosphor and light emitting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a red light-emitting phosphor that emits red light when excited by long-wavelength ultraviolet light or short-wavelength visible light of 350 to 420 nm, and a light-emitting device using the red light-emitting phosphor.
[0002]
[Prior art]
A light emitting diode (LED: Light Emitting Diode) is a semiconductor light emitting element that emits light, and converts electrical energy into ultraviolet light, visible light, infrared light, and the like. For example, as a device using visible light, there is a semiconductor light emitting element formed of a light emitting material such as GaP, GaAsP, or GaAlAs, and an LED lamp in which these are sealed with a transparent resin or the like is widely used. In addition, a display-type LED lamp in which a light emitting material is fixed on the upper surface of a printed circuit board or a metal lead and sealed with a transparent resin case shaped like a number or letter is also frequently used.
[0003]
In addition, since the light emitting diode is a semiconductor element, it has a long life, high reliability, and when used as a light source, the replacement work can be reduced. Therefore, portable communication devices, personal computer peripheral devices, OA devices, home use It is widely used as a component of various display devices such as electric devices, audio devices, various switches, backlight light sources, and bulletin boards.
[0004]
Such an LED lamp can change the color of light emitted from the LED lamp by including various phosphor powders in a transparent resin that seals the semiconductor light emitting device. Accordingly, it is possible to obtain a wide range of colors in the visible light region from blue to red.
[0005]
However, recently, demands from consumers for the colors of the above various display devices have increased, and the display devices have been required to have a performance capable of reproducing subtle hues more precisely, and white and various intermediate colors can be achieved with a single LED lamp. There is a strong demand to be able to emit light.
[0006]
Therefore, by applying various phosphors of red, green, and blue to the surface of the semiconductor light emitting element of the LED lamp, or by incorporating the various phosphors into the sealing material, coating material, etc. of the LED lamp, 1 Attempts have also been made to configure white LED and various intermediate colors with a single LED lamp.
[0007]
Among such phosphors, currently used as a phosphor that is excited by long-wavelength ultraviolet light or short-wavelength visible light (350 to 420 nm), the light emission color is BaMg.₂Al₁₆O₂₇: Eu, (Sr, Ca, Ba)_Five(PO_Four)_ThreeCl: Eu, green color of BaMg₂Al₁₆O₂₇: Eu, Mn, Zn₂GeO_Four: Mn, Y whose emission color is red₂O₂S: Eu, La₂O₂S: Eu, 3.5MgO / 0.5MgF₂・ GeO₂: Mn and the like, and by using these light emitting phosphors as appropriate, a wide range of emission colors can be obtained.
[0008]
However, the red light-emitting phosphor has a problem that light emission with respect to long-wavelength ultraviolet light and short-wavelength visible light (350 to 420 nm) is weaker than blue and green light-emitting phosphors.
[0009]
Therefore, when obtaining a white emission color using light of these wavelengths, the proportion of the red light emitting phosphor must be increased, the cost is increased, and the white emission color is red, green, Since white can be obtained by adjusting the balance of the blue light emission amount, in order to obtain a white light emission color, the green and blue light emission amounts must be reduced in accordance with the red light emission amount. In addition, since there is an upper limit to the amount of phosphor used, there is a problem in that the amount of white light obtained is reduced, and high brightness white cannot be obtained.
[0010]
Furthermore, the wavelength corresponding to the excitation energy of the electron pair of the oxide compound is in the ultraviolet region, and the wavelengths of long-wavelength ultraviolet light and short-wavelength visible light (350 to 420 nm) overlap with the absorption edge of the phosphor. The light emitting phosphor also has a problem that when the peak of the emission wavelength of the semiconductor light emitting element fluctuates, the light emission amount of the phosphor changes remarkably.
[0011]
In order to solve this problem, rare earth oxysulfide phosphors activated with europium have been proposed in JP-A-11-246857 (Patent Document 1) and JP-A 2000-144130 (Patent Document 2). Such a phosphor has been reported to have an excitation wavelength shifted to the longer wavelength side.
[0012]
However, even in these red light emitting phosphors, the absorption intensity on the longer wavelength side than 350 nm rapidly decreases as the wavelength becomes longer, and an excitation light source having an emission peak at 350 to 420 nm, for example, an ultraviolet LED is used as the excitation light source. When used, the light emission amount of the phosphor is remarkably changed due to fluctuations in the light emission wavelength of the LED, that is, the wavelength of the excitation light, which cannot be avoided in production. This means that when white and neutral colors are displayed in combination with green and blue light-emitting phosphors, the hue will vary, so the conventional red light-emitting phosphors will reproduce subtle colors more precisely. It was difficult.
[0013]
[Patent Document 1]
JP 11-246857 A
[Patent Document 2]
JP 2000-144130 A
[0014]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above-described problems. A light-emitting device or a green-emitting fluorescent light that can emit red light efficiently and with high luminance with respect to excitation light having a wavelength of 350 to 420 nm and displays red. It is an object of the present invention to provide a red light-emitting phosphor that can be used practically in a light-emitting device that displays white or an intermediate color in combination with a blue light-emitting phosphor and a light-emitting device using the red light-emitting phosphor.
[0015]
Means for Solving the Problem and Embodiment of the Invention
  As a result of intensive studies to solve the above problems, the present inventor is a red light emitting phosphor that emits light when excited by light having a wavelength of 350 to 420 nm, and has the following composition formula (1)
  AEu_xLn_(1-x)M₂O₈... (1)
(In the formula, A is at least one selected from the group consisting of Li, Na, K, Rb and Cs, and Ln is at least one selected from the group consisting of rare earth elements including Y (excluding Eu). M is at least one selected from the group consisting of W and Mo, and x is a positive number satisfying 0 <x ≦ 1.)
Represented byA part of A in the composition formula (1) was substituted with at least one selected from the group consisting of Mg, Ca, Sr and Ba added as a coactivator.The red light-emitting phosphor obtained by washing a fired product obtained by firing a raw material mixture in which raw materials containing elements constituting the red light-emitting phosphor are mixed with an alkaline aqueous solution has a wavelength of 350. It has been found that red light can be efficiently emitted with high luminance with respect to excitation light of ˜420 nm, and red can be emitted with a stable intensity with respect to a wide range of wavelengths from a long-wavelength ultraviolet ray to a short-wavelength visible light region.
[0016]
  Moreover, it is a red light-emitting phosphor that emits light when excited by light having a wavelength of 350 to 420 nm, and has the following composition formula (2)
  D_0.5Eu_yLn_(1-y)M₂O₈... (2)
(Wherein, D is at least one selected from the group consisting of Mg, Ca, Sr and Ba, Ln is at least one selected from the group consisting of rare earth elements including Y (excluding Eu), M Is at least one selected from the group consisting of W and Mo, and y is a positive number satisfying 0 <y ≦ 1.)
Represented byAndExcitation light having a wavelength of 350 to 420 nm is obtained by washing a fired product obtained by firing a raw material mixture containing raw materials containing elements constituting the red light emitting phosphor with an acid aqueous solution. In contrast, the present inventors have found that red light can be efficiently emitted with high luminance, and red can be emitted with a stable intensity with respect to a wide range of wavelengths from the long wavelength ultraviolet to the short wavelength visible light region.
[0017]
Further, these red light emitting phosphors are red light emitting phosphors that can be used practically in light emitting devices that display red, green light emitting phosphors, and light emitting devices that display white or intermediate colors in combination with blue light emitting phosphors. In particular, since this red light emitting phosphor is not easily affected by fluctuations in the wavelength of the excitation light, light emitted from a semiconductor light emitting element that emits light of the above wavelength in combination with a green light emitting phosphor or a blue light emitting phosphor. When the phosphor is caused to emit light to display white or an intermediate color, it has been found that a delicate hue can be displayed more precisely and with good reproducibility, and the present invention has been made.
[0018]
  That is, the present invention
[1] A red light-emitting phosphor that emits light when excited by light having a wavelength of 350 to 420 nm, and has the following composition formula (1)
  AEu_xLn_(1-x)M₂O₈... (1)
(In the formula, A is at least one selected from the group consisting of Li, Na, K, Rb and Cs, and Ln is at least one selected from the group consisting of rare earth elements including Y (excluding Eu). M is at least one selected from the group consisting of W and Mo, and x is a positive number satisfying 0 <x ≦ 1.)
Represented byA part of A in the composition formula (1) was substituted with at least one selected from the group consisting of Mg, Ca, Sr and Ba added as a coactivator.A red light-emitting fluorescent material characterized by being obtained by washing a fired product obtained by firing a raw material mixture obtained by mixing raw materials containing the elements constituting the red light-emitting phosphor with an alkaline aqueous solution body,
[2It is a red light emitting phosphor that emits light when excited by light having a wavelength of 350 to 420 nm, and has the following composition formula (2)
  D_0.5Eu_yLn_(1-y)M₂O₈... (2)
(Wherein, D is at least one selected from the group consisting of Mg, Ca, Sr and Ba, Ln is at least one selected from the group consisting of rare earth elements including Y (excluding Eu), M Is at least one selected from the group consisting of W and Mo, and y is a positive number satisfying 0 <y ≦ 1.)
Represented byAnd obtained by washing a fired product obtained by firing a raw material mixture obtained by mixing raw materials containing the elements constituting the red light emitting phosphor with an aqueous acid solution.A red-emitting phosphor characterized in that,
[3Ln in the above formula is at least one selected from the group consisting of Y, La, Gd and Lu [1]Or [2]The red light emitting phosphor as described,
[4A light-emitting device in which a semiconductor light-emitting element that emits light having a wavelength of 350 to 420 nm is sealed in a sealing material, and the sealing material includes [1] to [1]3A light-emitting device, wherein the red-emitting phosphor according to any one of the above is dispersed;
[5A light-emitting device in which a semiconductor light-emitting element that emits light having a wavelength of 350 to 420 nm is encapsulated in a sealing material, and [1] to [[3A light emitting device comprising a fluorescent layer containing the red light emitting phosphor according to any one of the above,
[6A fluorescent layer is provided on the semiconductor light emitting device or the sealing material.5A light-emitting device according to claim 1, and
[7The fluorescent layer is formed by dispersing the red light-emitting phosphor in a resin, rubber, elastomer, or glass.6] The light-emitting device of description
I will provide a.
[0019]
The present invention will be described in detail below.
First, the 1st aspect of the red light emission fluorescent substance of this invention is demonstrated. The red light-emitting phosphor according to the first aspect is a red light-emitting phosphor that emits light when excited by light having a wavelength of 350 to 420 nm, and has the following composition formula (1)
AEu_xLn_(1-x)M₂O₈... (1)
(In the formula, A is at least one selected from the group consisting of Li, Na, K, Rb and Cs, and Ln is at least one selected from the group consisting of rare earth elements including Y (excluding Eu)) , M is at least one selected from the group consisting of W and Mo, and x is a positive number satisfying 0 <x ≦ 1, preferably 0.3 ≦ x ≦ 1, particularly preferably 0.5 ≦ x ≦ 1. .)
The fired product obtained by firing a raw material mixture obtained by mixing the raw materials containing the elements constituting the red light emitting phosphor is washed with an alkaline aqueous solution.
[0020]
This red light-emitting phosphor is obtained by firing a raw material mixture obtained by mixing, for example, an oxide, carbonate, or the like containing an element constituting the red light-emitting phosphor with a ball mill or the like, and grinding and sieving as necessary. In this case, for example, a lithium hydroxide aqueous solution, a sodium hydroxide aqueous solution, or a potassium hydroxide aqueous solution may be used as the alkaline aqueous solution. The pH is preferably 8 or more. Washing with an aqueous alkali solution is possible by a method such as immersing the fired product in an aqueous alkali solution and stirring as necessary. The fired product washed with the aqueous alkali solution is further separated from the aqueous alkaline solution, washed with water, A red light-emitting phosphor can be obtained by drying.
[0021]
In the composition formula (1), Ln is at least one selected from the group consisting of rare earth elements including Y (excluding Eu), and among these, Y, La, Gd, or Lu is preferable. A is preferably at least one selected from the group consisting of Li and Na having an ionic radius close to Eu. As such, LiEuM₂O₈, LiEu_xY_(1-x)M₂O₈Is particularly preferred.
[0022]
Furthermore, in the present invention, one of the red light emitting phosphors represented by the composition formula (1) in the formula (that is, at least one selected from the group consisting of Li, Na, K, Rb and Cs). It is also preferable that the part is substituted with at least one selected from the group consisting of Mg, Ca, Sr and Ba added as a coactivator. The substitution rate in this case is less than 0.5 (atomic ratio), preferably 0.3 (atomic ratio) or less, in terms of the ratio of the total amount of Mg, Ca, Sr and Ba to the total amount of Li, Na, K, Rb and Cs. More preferably, it is 0.2 (atomic ratio) or less, and particularly preferably 0.1 (atomic ratio) or less.
[0023]
Next, a second aspect of the red light emitting phosphor of the present invention will be described. The red light-emitting phosphor of the second embodiment is a red light-emitting phosphor that emits light when excited by light having a wavelength of 350 to 420 nm, and has the following composition formula (2)
D_0.5Eu_yLn_(1-y)M₂O₈... (2)
(Wherein, D is at least one selected from the group consisting of Mg, Ca, Sr and Ba, Ln is at least one selected from the group consisting of rare earth elements including Y (excluding Eu), M Is at least one selected from the group consisting of W and Mo, and y is a positive number satisfying 0 <y ≦ 1, preferably 0.3 ≦ y ≦ 1, particularly preferably 0.5 ≦ y ≦ 1. .)
It is represented by
[0024]
This red light-emitting phosphor is obtained by firing a raw material mixture obtained by mixing, for example, an oxide or carbonate containing an element constituting the red light-emitting phosphor with a ball mill or the like, and pulverizing and sieving as necessary. In particular, it is preferable that the fired product obtained by this method is further washed with an acid aqueous solution. In this case, as the acid aqueous solution, for example, a hydrochloric acid aqueous solution, a sulfuric acid aqueous solution, a nitric acid aqueous solution or the like can be used, and the pH is preferably 6 or less. Washing with an acid aqueous solution can be performed by immersing the fired product in an acid aqueous solution and stirring as necessary. The fired product washed with the acid aqueous solution is further separated from the acid aqueous solution, washed with water, A red light-emitting phosphor can be obtained by drying.
[0025]
In the compositional formula (2), Ln is at least one selected from the group consisting of rare earth elements including Y (excluding Eu). Among these, Y, La, Gd, or Lu is preferably exemplified. Further, D is preferably at least one selected from the group consisting of Ca and Sr having an ionic radius close to Eu.
[0026]
Further, in the red light emitting phosphor of the present invention, Eu constituting the red light emitting phosphor is a trivalent Eu ion (Eu³⁺In particular, it is preferable that the trivalent Eu ions are arranged two-dimensionally or one-dimensionally. Here, the trivalent Eu ions are arranged two-dimensionally, as shown in FIG. 1, the trivalent Eu ions in the red light-emitting phosphor are arranged in a plane and are only trivalent Eu ions. In a state in which a planar structure is formed, a structure in which trivalent Eu ions are arranged one-dimensionally means that trivalent Eu ions in a red light emitting phosphor are arranged in a straight line as shown in FIG. This refers to a state in which a linear structure is formed only by valence Eu ions.
[0027]
Oxide phosphors absorb excitation light by the host crystal and transmit the excitation energy to luminescent ions to emit light, but in general oxide phosphors, the wavelength corresponding to the excitation energy of electron pairs is in the ultraviolet region. Therefore, absorption of long-wavelength ultraviolet rays to short-wavelength visible rays (350 to 420 nm) is not sufficient.
[0028]
Further, in a general phosphor, the concentration of luminescent ions (activator) is added by several mol% with respect to the base crystal, and at a concentration higher than that, (1) cross relaxation occurs due to resonance transmission between activators, Part of the excitation energy is lost. (2) Excitation migration occurs due to resonance transfer between activators, which promotes the transfer and extinction of excitation to the crystal surface and non-luminescent center. (3) Activator It is known that concentration quenching occurs for reasons such as non-radiative centers and killer (fluorescence inhibitor) being formed by aggregation of each other or formation of ion pairs.
[0029]
On the other hand, trivalent Eu ions arranged in two dimensions or one dimension are trivalent Eu ions (Eu³⁺) Acts as absorption and emission center of excitation light, and trivalent Eu ions which are luminescent ions directly absorb short wavelength visible light (350 to 420 nm) from long wavelength ultraviolet rays. Furthermore, since the distance between the layers where the light-emitting ions are arranged is wide, concentration quenching is not shown by controlling the excitatory energy migration. From this, it is possible to efficiently absorb short-wavelength visible light (350 to 420 nm) from long-wavelength ultraviolet light by unpaired electrons in the 4f orbit of trivalent Eu ions, so that high-luminance red light emission can be obtained.
[0030]
Next, the light emitting device of the present invention will be described.
First, the 1st aspect of the light-emitting device of this invention is demonstrated. The light-emitting device according to the first aspect is a light-emitting device in which a semiconductor light-emitting element that emits light having a wavelength of 350 to 420 nm is sealed in a sealing material. A red light emitting phosphor is dispersed.
[0031]
Specifically, as shown in FIG. 3, leads 1 and 2, a semiconductor light emitting element 3 that emits light having a wavelength of 350 to 420 nm, and a lead thin wire 4 that electrically connects the semiconductor light emitting element 3 and the lead 2. Of a so-called shell-type light emitting diode having a structure sealed in a shell shape with a sealing material 5 or a pair of box-shaped light emitter housing members 6 having an open top surface as shown in FIG. The leads 1 and 2 are extended to the outside of the light emitter housing member 6, and the semiconductor light emitting element 3 and the lead thin wires 4 and 4 that emit light having a wavelength of 350 to 420 nm are housed inside the light emitter housing member 6. Are obtained by dispersing the red light emitting phosphor of the present invention in a sealing material 5 such as a so-called chip-type light emitting diode having a structure in which the inside of the light emitting body housing member 6 is sealed with a sealing material 5. Can be mentioned.
[0032]
In this case, if only the above-described red light-emitting phosphor of the present invention is dispersed in the sealing material 5, a light-emitting device that emits red with high luminance is obtained.₂Al₁₆O₂₇: Eu, Mn, Zn₂GeO_Four: Green light emitting phosphor such as Mn, BaMg₂Al₁₆O₂₇: Eu, (Sr, Ca, Ba)_Five(PO_Four)_ThreeWhen dispersed together with a blue fluorescent light emitting material such as Cl: Eu, a light emitting device that emits white or intermediate color with high luminance is obtained. In any of these light emitting devices, red light emitting phosphors other than the red light emitting phosphor of the present invention, such as Y₂O₂S: Eu, La₂O₂S: Eu, 3.5MgO / 0.5MgF₂・ GeO₂: Mn or the like can be added.
[0033]
This light-emitting device can be manufactured by mixing a phosphor with a sealing material such as resin, rubber, elastomer, or glass when sealing a semiconductor light-emitting element or the like. In particular, when a plurality of types of phosphors are used, the red light emitting phosphor of the present invention has a higher true specific gravity than a general phosphor, and therefore settles faster than other phosphors when mixed with a sealing material. May cause uneven color. Therefore, the red light-emitting phosphor of the present invention is mixed with a high viscosity material such as a silicone rubber composition or a silicone resin composition whose viscosity is adjusted with a thixotropy adjusting agent, and then cured in a sealing material. It is preferable to be dispersed. In addition to the phosphor described above as a color tone conversion material, pigments, dyes, pseudo pigments, and the like may be added to the sealing material.
[0034]
Next, a second aspect of the light emitting device of the present invention will be described. The light-emitting device according to the second aspect is a light-emitting device in which a semiconductor light-emitting element that emits light having a wavelength of 350 to 420 nm is sealed in a sealing material, and the light emitted from the semiconductor light-emitting element. A fluorescent layer containing the above-described red light emitting phosphor of the present invention is provided on the road.
[0035]
As such a thing, what provided the fluorescent layer containing the red light emission fluorescent substance of this invention on a semiconductor light emitting element or a sealing material, for example is mentioned, Specifically, as shown in FIG. The lead 1 and 2, the semiconductor light emitting device 3 that emits light having a wavelength of 350 to 420 nm, and the lead thin wire 4 that electrically connects the semiconductor light emitting device 3 and the lead 2 are sealed in a shell shape with a sealing material 5. A so-called shell-type light-emitting diode semiconductor light-emitting element 3 having a fluorescent layer 9 and sealed together with the semiconductor light-emitting element 3 and the like, and a box-shaped light-emitting body with an open top as shown in FIG. A pair of leads 1 and 2 are extended from the inner bottom of the housing member 6 to the outside of the light emitter housing member 6, and the semiconductor light emitting element 3 and leads that emit light having a wavelength of 350 to 420 nm inside the light emitter housing member 6. Accommodates fine wires 4 and 4 Subsequently, a phosphor layer 7 is provided on the semiconductor light emitting element 3 of a so-called chip-type light emitting diode having a structure in which the inside of the light emitter housing member 6 is sealed with the sealing material 5 and sealed together with the semiconductor light emitting element 3 and the like. 7, a bullet-type light emitting diode as shown in FIG. 7 provided with a fluorescent layer 7 so as to cover the sealing material 5, a chip type light emitting diode as shown in FIG. The thing which provided the fluorescent layer 7 on the sealing material 5 of this is mentioned. 7 and FIG. 8 are the same as those shown in FIG. 3 and FIG.
[0036]
Further, the fluorescent layer 7 is not limited to the so-called transmission type in which the fluorescent layer is provided in the light emitting diode or adjacent to the light emitting diode as described above, and the fluorescent layer 7 is separated from the light emitting diode 8 as shown in FIG. There is also a so-called reflection type light-emitting device that is provided at a position and reflects light emitted from the fluorescent layer by the reflection plate 9. In addition, the fluorescent layer of the light emitting device in which the fluorescent layer is provided on the sealing material as illustrated in FIGS. 7 and 8 can be further sealed with the sealing material.
[0037]
In this case, if only the above-described red light-emitting phosphor of the present invention is dispersed in the fluorescent layer, a light-emitting device that emits high-brightness red is obtained.₂Al₁₆O₂₇: Eu, Mn, Zn₂GeO_Four: Green light emitting phosphor such as Mn, BaMg₂Al₁₆O₂₇: Eu, (Sr, Ca, Ba)_Five(PO_Four)_ThreeWhen dispersed together with a blue fluorescent light emitting material such as Cl: Eu, a light emitting device that emits white or intermediate color with high luminance is obtained. In any of these light emitting devices, red light emitting phosphors other than the red light emitting phosphor of the present invention, such as Y₂O₂S: Eu, La₂O₂S: Eu, 3.5MgO / 0.5MgF₂・ GeO₂: Mn or the like can be added.
[0038]
In addition, when providing a fluorescent layer on a semiconductor light-emitting device, the phosphor may be used as it is or may be mixed with a binder. In this case, as shown in FIGS. 5 and 6, the fluorescent layer is sealed in the sealing material together with the semiconductor light emitting element.
[0039]
On the other hand, when the fluorescent layer is provided on the sealing material, it is preferable to use the red light-emitting phosphor dispersed in a light-transmitting resin, rubber, elastomer or glass, particularly silicone resin or silicone rubber. In particular, when a plurality of types of phosphors are dispersed in the phosphor layer, as in the case of dispersing the red light-emitting phosphor of the present invention in the sealing material described above, a silicone rubber composition and a silicone resin whose viscosity is adjusted with a thixotropic modifier It is preferable to disperse in the phosphor layer by a method of mixing with a composition or the like and curing it. The fluorescent layer may be a single layer obtained by mixing phosphors, or may be a laminate of phosphors divided into several layers. In addition to the phosphor described above as a color tone conversion material, pigments, dyes, pseudo pigments, and the like may be added to the fluorescent layer.
[0040]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to the following Example.
[0041]
[Example 1]
WO as phosphor constituent material_Three46.37 g of powder, Eu₂O_Three17.60 g of powder, Li₂CO_Three3.69 g of each powder was weighed and uniformly mixed with a ball mill to obtain a raw material mixture.
[0042]
Next, the obtained raw material mixture was put in an alumina crucible and fired at a temperature of 900 ° C. for 6 hours. The obtained fired product is sufficiently washed with pure water to remove unnecessary soluble components, and then finely pulverized with a ball mill and sieved (aperture 53 μm). Apply alkaline aqueous solution washing treatment soaked for minutes, then wash with water, filter and dry to LiEuW₂O₈A red light-emitting phosphor having the following composition was obtained.
[0043]
This red light emitting phosphor LiEuW₂O₈When luminescence intensity was measured with a compact spectrofluorometer FP-750 (manufactured by JASCO Corporation) under excitation at 380 nm, the relative luminescence intensity when the luminescence intensity was 100 when the alkaline aqueous solution cleaning treatment was not performed. Was as high as 120.1.
[0044]
[Examples 2 to 4]
PH = 11 lithium hydroxide aqueous solution (Example 2), pH = 11 sodium hydroxide aqueous solution (Example 3), pH = 11 potassium hydroxide aqueous solution (Example 4) instead of 2% sodium hydroxide aqueous solution LiEuW in the same manner as in Example 1 except that₂O₈A red light-emitting phosphor having the following composition was obtained.
[0045]
These red light emitting phosphors LiEuW₂O₈When luminescence intensity was measured with a compact spectrofluorometer FP-750 (manufactured by JASCO Corporation) under excitation at 380 nm, the relative luminescence intensity when the luminescence intensity was 100 when the alkaline aqueous solution cleaning treatment was not performed. Of 101.0 (Example 2), 103.3 (Example 3), and 108.4 (Example 4).
[0046]
[Example 5]
WO as phosphor constituent material_Three46.37 g of powder, Eu₂O_Three17.60 g of powder, CaCO_Three5.00 g of each powder was weighed and mixed uniformly with a ball mill to obtain a raw material mixture.
[0047]
Next, the obtained raw material mixture was put in an alumina crucible and fired at a temperature of 900 ° C. for 6 hours. The obtained fired product is thoroughly washed with pure water to remove unnecessary soluble components, and then finely pulverized with a ball mill and sieved (opening 53 μm) to obtain Ca._0.5EuW₂O₈A red light-emitting phosphor having the following composition was obtained.
[0048]
This red light emitting phosphor Ca_0.5EuW₂O₈Under conventional excitation at 380 nm₂O₂When the emission intensity was measured with a small spectrofluorometer FP-750 (manufactured by JASCO Corporation) using S: Eu phosphor as a standard, a value as high as 1.11 times was obtained.
[0049]
[Example 6]
WO as phosphor constituent material_Three46.37 g of powder, Eu₂O_Three17.60 g of powder, CaCO_Three5.00 g of each powder was weighed and mixed uniformly with a ball mill to obtain a raw material mixture.
[0050]
Next, the obtained raw material mixture was put in an alumina crucible and fired at a temperature of 900 ° C. for 6 hours. The obtained fired product is thoroughly washed with pure water to remove unnecessary soluble components, then finely pulverized with a ball mill, sieved (aperture 53 μm), and immersed in a 2% aqueous hydrochloric acid solution for 30 minutes. The solution is washed with water, filtered, dried and then washed with Ca._0.5EuW₂O₈A red light-emitting phosphor having the following composition was obtained.
[0051]
This red light emitting phosphor Ca_0.5EuW₂O₈When luminescence intensity was measured with a small spectrofluorometer FP-750 (manufactured by JASCO Corporation) under excitation at 380 nm, the relative luminescence intensity when the luminescence intensity was 100 when the acid aqueous solution washing treatment was not performed Was as high as 117.5.
[0052]
【The invention's effect】
As described above, the red light-emitting phosphor of the present invention emits red light efficiently and with high luminance with respect to excitation light having a wavelength of 350 to 420 nm, and a light-emitting device using this red light-emitting phosphor. The light emission luminance in the red region can be significantly improved, and red can be emitted with a stable intensity with respect to a wide range of wavelengths from the long wavelength ultraviolet region to the short wavelength visible region.
[0053]
In addition, since this red light emitting phosphor is not easily affected by fluctuations in the wavelength of the excitation light, it is fluorescent by light from a semiconductor light emitting element that emits light of the above wavelength in combination with the green light emitting phosphor and the blue light emitting phosphor. When displaying a white or intermediate color by emitting light from the body, it is possible to display a subtle hue more precisely and with good reproducibility.
[Brief description of the drawings]
FIG. 1 Trivalent Eu ion (Eu³⁺) Is an explanatory diagram for explaining a state in which the two-dimensional array is arranged in two dimensions.
FIG. 2 Trivalent Eu ions (Eu³⁺) Is an explanatory diagram for explaining a state in which they are arranged one-dimensionally.
FIG. 3 is a diagram showing an example of the optical device of the present invention, and is a cross-sectional view showing a light emitting device in which the red light emitting phosphor of the present invention is dispersed in a shell-type light emitting diode sealing material.
FIG. 4 is a diagram showing an example of the optical device of the present invention, and is a cross-sectional view showing a light emitting device in which the red light emitting phosphor of the present invention is dispersed in a sealing material for a chip type light emitting diode.
FIG. 5 is a diagram showing an example of the optical device of the present invention, and is a cross-sectional view showing a light emitting device in which a fluorescent layer containing the red light emitting phosphor of the present invention is provided on a semiconductor light emitting element of a shell-type light emitting diode. .
FIG. 6 is a diagram showing an example of the optical device of the present invention, and is a cross-sectional view showing a light emitting device in which a fluorescent layer containing the red light emitting phosphor of the present invention is provided on a semiconductor light emitting element of a chip type light emitting diode. .
FIG. 7 is a diagram showing an example of the optical device of the present invention, and is a cross-sectional view showing a light emitting device in which a fluorescent layer containing the red light emitting phosphor of the present invention is provided on a sealing material of a shell-type light emitting diode. .
FIG. 8 is a diagram showing an example of the optical device of the present invention, and is a cross-sectional view showing a light emitting device in which a phosphor layer containing the red light emitting phosphor of the present invention is provided on a sealing material of a chip type light emitting diode. .
FIG. 9 is a diagram showing an example of an optical device according to the present invention, and is a cross-sectional view showing a light emitting device that provides a fluorescent layer at a position away from a light emitting diode and reflects light emitted from the fluorescent layer.
[Explanation of symbols]
1, 2 lead
3 Semiconductor light emitting device
4 Lead wire
5 Sealing material
6 Light emitter housing member
7 Fluorescent layer
8 Light emitting diode
9 Reflector

Claims (7)

A red light-emitting phosphor that emits light when excited by light having a wavelength of 350 to 420 nm, the composition formula (1)
AEu _x Ln _(1-x) M ₂ O ₈ (1)
(In the formula, A is at least one selected from the group consisting of Li, Na, K, Rb and Cs, and Ln is at least one selected from the group consisting of rare earth elements including Y (excluding Eu). M is at least one selected from the group consisting of W and Mo, and x is a positive number satisfying 0 <x ≦ 1.)
And a part of A in the composition formula (1) is substituted with at least one selected from the group consisting of Mg, Ca, Sr and Ba added as a coactivator . And a red light-emitting phosphor obtained by washing a fired product obtained by firing a raw material mixture obtained by mixing raw materials containing elements constituting the red light-emitting phosphor with an alkaline aqueous solution. A red light emitting phosphor that emits light when excited by light having a wavelength of 350 to 420 nm, the composition formula (2)
D _0.5 Eu _y Ln _(1-y) M ₂ O ₈ (2)
(Wherein, D is at least one selected from the group consisting of Mg, Ca, Sr and Ba, Ln is at least one selected from the group consisting of rare earth elements including Y (excluding Eu), M Is at least one selected from the group consisting of W and Mo, and y is a positive number satisfying 0 <y ≦ 1.)
And is obtained by washing a fired product obtained by firing a raw material mixture obtained by mixing raw materials containing the elements constituting the red light emitting phosphor with an acid aqueous solution. Red light emitting phosphor. The red light-emitting phosphor according to claim 1 or 2 , wherein Ln in the above formula is at least one selected from the group consisting of Y, La, Gd and Lu. The semiconductor light-emitting device having a wavelength to emit light of 350~420nm is a light-emitting device in which sealed in the sealing material, the red light-emitting phosphor of any one of claims 1 to 3 in the sealing material A light emitting device in which a body is dispersed. The semiconductor light-emitting device having a wavelength to emit light of 350~420nm is a light-emitting device in which sealed in the sealing material, any one of claims 1 to 3 on the optical path of light emitted from the semiconductor light emitting element A light emitting device comprising a fluorescent layer containing the red light emitting phosphor according to item 1. The light emitting device according to claim 5, characterized in that a fluorescent layer in the semiconductor light-emitting element or on the sealing material on. 7. The light emitting device according to claim 6, wherein the fluorescent layer is formed by dispersing the red light emitting phosphor in resin, rubber, elastomer or glass.

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