JP2013227398A - Composite phosphor and manufacturing method thereof - Google Patents

Abstract

To reduce the amount of phosphor, that is, to reduce the amount of rare earth elements used, and to produce a new composite phosphor capable of realizing a white light emitting diode using a yellow phosphor.
In a yellow phosphor used as a color conversion material for a white light emitting diode, the surface of an inorganic phosphor particle 101 is coated with an organic phosphor 102 containing 3,5-diacetyl-1,4-dihydrolutidine. With such a structure, yellow light emission from not only inorganic phosphors but also organic phosphors can be used, and an excellent phosphor with high luminance and reduced use of rare earth elements can be realized.
[Selection] Figure 1

Description

  The present invention relates to a composite phosphor having improved emission intensity and emission efficiency in a phosphor that converts blue light into yellow, and a method for producing the same.

 In recent years, research and development of semiconductor elements composed of nitride semiconductors typified by gallium nitride (GaN) have been actively conducted. Semiconductor light-emitting devices composed of nitride semiconductors composed of aluminum nitride (AlN), GaN, indium nitride (InN) and mixed crystals thereof have a wide wavelength range from ultraviolet or blue to infrared regions by controlling the film composition. Light emission can be realized in the region. As an application example thereof, a visible light emitting diode using a nitride semiconductor has already been commercialized (for example, Non-Patent Document 1).

  Furthermore, a light-emitting device is known that combines a light-emitting element having a light emission peak in a blue region with a wavelength of 420 nm or more and less than 500 nm (hereinafter referred to as a blue light-emitting element) and a phosphor excited by light emitted from the blue light-emitting element. (For example, refer to Patent Document 1).

In the light emitting device using the blue light emitting element, yttrium aluminum garnet (Y ₃ Al ₅ O ₁₂ : Ce, hereinafter referred to as YAG phosphor) is used as a light emitting device that emits white light and achieves both high luminous flux and high color rendering. A light emitting device using a phosphor is known (for example, see Patent Documents 2 and 3).

  FIG. 4 shows a cross-sectional configuration of a conventional white LED element.

  4 includes a package 401, a blue LED chip 402, a lead terminal 403, and a wiring wire 404. Inside the package 401, YAG yellow phosphor particles 405 are sealed with a silicone resin 406. ing.

JP 2004-103443 A JP 2005-101296 A JP 2008-300124 A

Shuji Nakamura et. al. , Jpn. J. et al. Appl. Phys. Vol. 34 (1995) L. 1332-L. 1335

  In order to obtain a desired emission intensity at a constant excitation light intensity in a phosphor layer using a yellow phosphor such as a YAG phosphor, it is necessary to increase the thickness of the phosphor layer or the Ce content. There is. Luminous properties deteriorate due to segregation of Ce which cannot cause solid solution in YAG base material due to excessive Ce content due to leakage of fluorescent component from side of light emitting element due to thick phosphor layer There is a risk of malfunctions such as There is a demand for a reduction in the amount of phosphor due to improvement in emission intensity and luminous efficiency of the phosphor.

  In addition, as the demand for phosphors using rare earths such as Y and Ce increases, the amount of rare earth elements to be used becomes larger. However, rare earth elements have a problem of low reserves and high unit price per unit weight. It is also necessary to protect valuable resources from the viewpoint of protecting the natural environment. Furthermore, the amount of rare earth elements in the phosphor is increasing, and even if the rare earth elements are recovered from the phosphor waste, it is not realized because enormous energy is required.

  An object of the present invention is to solve the above-described conventional problems, and by providing a novel phosphor, a yellow phosphor that can reduce the amount of phosphor, that is, the amount of rare earth elements used can be reduced. It aims at providing the used white LED.

  In order to solve the above-mentioned conventional problems, the composite phosphor of the present invention is obtained by replacing inorganic phosphor particles with 3,5-diacetyl-1,4-dihydrolutidine in a yellow phosphor used as a color conversion material for a white light emitting diode. It has a structure coated with an organic fluorescent material containing.

  In the composite phosphor of the present invention, it is preferable to use a YAG phosphor as the phosphor particles.

  Further, as a method for producing the composite phosphor of the present invention, the inorganic phosphor particles are reacted with an inorganic phosphor particle dispersion liquid containing acetylacetone or an acetylacetonate metal complex and hexamethylenetetramine at a predetermined temperature, and the inorganic phosphor particles are reacted. A method for producing a composite phosphor having a step of coating body particles with an organic phosphor containing 3,5-diacetyl-1,4-dihydrolutidine is used.

  According to the composite phosphor of the present invention, since the phosphor particles have a structure in which the phosphor particles are coated with an organic phosphor containing 3,5-diacetyl-1,4-dihydrolutidine, not only a YAG phosphor but also an organic phosphor. Can be used, and an excellent phosphor with high luminance and reduced use of rare earth elements can be realized.

The cross-sectional schematic diagram of the composite fluorescent substance in embodiment of this invention. The figure which shows the surface SEM observation image of the composite fluorescent substance in embodiment of this invention. The comparison figure of the emission spectrum of the composite fluorescent substance in embodiment of this invention, and the conventional YAG fluorescent substance. The cross-sectional block diagram of the conventional white LED element.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a schematic cross-sectional view of a composite phosphor according to an embodiment of the present invention. In FIG. 1, 101 is a YAG phosphor, and 102 is an organic fluorescent substance containing 3,5-diacetyl-1,4-dihydrolutidine.

  Hereinafter, a method for manufacturing the phosphor configured as described above will be described. A phosphor dispersion solution was prepared using a YAG phosphor having an average particle diameter of 3 μm. In a dispersion solvent ethanol (30 ml), 0.1 g of YAG phosphor, 0.001 g of phosphate ester and 0.001 g of polyethyleneimine as a dispersant for improving the dispersibility of YAG phosphor are mixed, and an ultrasonic homogenizer. Was used to disperse phosphor particles in a solvent.

Next, 0.1 g of acetylacetone (C ₅ H ₈ O ₂ ) was added to the obtained phosphor dispersion solution and sufficiently stirred.

Further, an aqueous solution of hexamethylenetetramine ((CH ₂ ) ₆ N ₄ ) having a concentration of 0.1 mol / L was added dropwise to adjust the ph value to 5-7.

When the phosphor dispersion liquid to which all the above materials were added was allowed to stand for 12 to 24 hours while maintaining at 90 ° C., the colorless phosphor dispersion liquid changed to a yellow solution close to orange. This is because an organic fluorescent substance containing 3,5-diacetyl-1,4-dihydrolutidine reacts with formaldehyde (HCOH) and ammonia ions (NH ⁴⁺ ) generated by the decomposition reaction of hexamethylenetetramine and acetylacetone. This is because it was produced in the phosphor dispersion solution. Thereafter, the solvent was dried to obtain a composite phosphor in which YAG phosphor particles were coated with an organic phosphor containing 3,5-diacetyl-1,4-dihydrolutidine.

  FIG. 2 shows a surface SEM photograph of the phosphor produced by the phosphor manufacturing method according to the embodiment of the present invention. As is apparent from FIG. 2, it can be seen that the surface of the YAG phosphor particles is coated with an organic substance. When the energy dispersive X-ray analysis of the composite phosphor shown in FIG. 2 was performed, yttrium (Y), aluminum (Al), oxygen (O) was detected, and the composite phosphor was coated with an organic substance. It turned out to be a particle.

  FIG. 3 shows a comparison of emission spectra of the conventional YAG phosphor and the composite phosphor according to the embodiment of the present invention. In FIG. 3, 301 is the emission spectrum of the conventional YAG phosphor, and 302 is the emission spectrum of the composite phosphor according to the embodiment of the present invention. Measurement of the emission spectrum was performed at an excitation wavelength of 460 nm by placing 3 ml of the phosphor dispersion solution in a quartz glass cell and placing it in a fluorescence spectrometer. As is apparent from FIG. 3, the emission peak of the emission spectrum 302 of the composite phosphor according to the embodiment of the present invention showed a wide spectrum extending from around 470 nm to around 600 nm. Compared to the conventional YAG phosphor, the peak height was about 6 times at a yellow wavelength of 530 nm. Therefore, an excellent phosphor with high brightness and reduced use amount of rare earth elements by adopting a structure in which phosphor particles are coated with an organic phosphor containing 3,5-diacetyl-1,4-dihydrolutidine. Can be realized.

  In addition, although acetylacetone was used as the material of 3,5-diacetyl-1,4-dihydrolutidine in the above, a metal complex coordinated with acetylacetonate, which is a conjugate base of acetylacetone, may be used. For example, when zinc acetylacetonate was used as a material, a similar composite phosphor could be obtained.

  Table 1 shows a comparison of the emission intensity of the conventional YAG phosphor and the composite phosphor according to the embodiment of the present invention.

  As is apparent from Table 1, the emission intensity is obtained by forming a composite phosphor coated with an organic phosphor containing 3,5-diacetyl-1,4-dihydrolutidine as compared with the conventional YAG phosphor of the comparative example. It can be seen that there is a large increase. In order to obtain a light emission intensity equivalent to that of conventional YAG phosphor particles, the amount of YAG phosphor used in the composite phosphor is 1/6 or less, and the amount of rare earth elements used can be greatly reduced.

  As described above, by using the structure of the phosphor and the manufacturing method thereof according to the embodiment of the present invention, yellow light emission from not only the YAG phosphor but also the organic phosphor can be used. It turns out that the outstanding fluorescent substance which reduced the usage-amount of can be implement | achieved.

  The composite phosphor according to the present invention has a structure in which the surface of an inorganic phosphor particle is coated with an organic phosphor, and can be applied as an excellent light source such as illumination and a wavelength conversion material.

DESCRIPTION OF SYMBOLS 101 Inorganic fluorescent substance particle 102 Organic fluorescent substance containing 3, 5- diacetyl- 1, 4- dihydrolutidine 401 Package 402 Blue LED chip 403 Lead terminal 404 Wiring wire 405 Conventional YAG fluorescent substance 406 Silicone resin

Claims (5)

  A composite phosphor having a structure in which inorganic phosphor particles emitting yellow light are coated with an organic phosphor containing 3,5-diacetyl-1,4-dihydrolutidine. The composite phosphor according to claim 1, wherein the inorganic phosphor particles are made of Y ₃ Al ₅ O ₁₂ : Ce.   The inorganic phosphor particles are reacted with an inorganic phosphor particle dispersion containing acetylacetone and hexamethylenetetramine at a predetermined temperature, and the inorganic phosphor particles are subjected to organic fluorescence containing 3,5-diacetyl-1,4-dihydrolutidine. A method for producing a composite phosphor comprising a step of coating with a substance.   The inorganic phosphor particles are reacted with an inorganic phosphor particle dispersion containing acetylacetonate metal complex and hexamethylenetetramine at a predetermined temperature, and the inorganic phosphor particles are reacted with 3,5-diacetyl-1,4-dihydrolutidine. A method for producing a composite phosphor comprising a step of coating with an organic fluorescent material containing The inorganic phosphor particles Y ₃ Al ₅ O _12: The method according to claim 3 or 4 composite phosphor according to characterized in that it consists of Ce.

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