# Patent

## Title
Light emitting device and image display device

## Abstract

By a light emitting device including a light emitting element, and a semiconductor phosphor microparticle having a core/shell structure having a shell part absorbing at least a part of the light emitted by the light emitting element, and an image display device including a light emitting element, and a semiconductor phosphor microparticle having a core/shell structure having a shell part that absorbs at least a part of the light emitted by the light emitting element, a light emitting device and an image display device having high luminous efficiency are provided.

## Background
This nonprovisional application is based on Japanese Patent Application No. 2009-184837 filed on Aug. 7, 2009 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a light emitting device and an image display device having a light emitting element and a phosphor. The semiconductor light emitting device and image display device in the present invention may be used for various use applications including a light source for display, an alternate light source for a small bulb, a backlight light source for a liquid crystal display panel, general illumination, decorative illumination, a luminescence display device, a display, and a projector.
2. Description of the Background Art
In recent years, the light emitting diode (LED) element that is formed of a gallium nitride-based compound semiconductor material attracts a great deal of interest. The light emitting diode element is characterized by small size, light weight, energy saving, long product life time, resistance to repeated ON/OFF lighting and so on. Therefore, by combining a light emitting diode element radiating blue light or ultraviolet light with various phosphors emitting part of light radiated from the light emitting diode device as an excitation source, light emitting devices outputting light of the colors including white that are different from that of the light emitting by the LED chip are developed. Such a light emitting device is a promising illumination device alternative to an incandescent lamp, a fluorescent lamp and the like.
As a phosphor used in such a light emitting device, a semiconductor phosphor microparticle attracts interests as an alternative to a conventionally used rare earth activated phosphor. The semiconductor phosphor microparticle allows arbitrary control of emission wavelength that was not realized by conventional phosphors. Therefore, a light emitting device using such a semiconductor phosphor microparticle is able to have various emission spectrums. This technique is a promising technique that enables fabrication of a light emitting device having a high color rendering property and high efficiency.
Fabrication of a light emitting device including a semiconductor light emitting element and a semiconductor phosphor microparticle as described above is currently studied and disclosed, for example, in Japanese Patent Laying-Open No. 2007-103512 (Patent document 1). Patent document 1 discloses a light emitting device wherein rare earth activated phosphors are used as blue and green phosphors, and semiconductor phosphor microparticles are used as yellow and red phosphors.
On the other hand, an organic electric-field light emitting element using an organic substance is greatly expected for applications as a surface light emitting element and a large area full color display device, and developed actively. However, the conventional organic electric-field light emitting element is difficult to be brought into practical use because of its low luminous efficiency.
SUMMARY OF THE INVENTION
However, the light emitting device described in Patent document 1 was difficult to realize high luminous efficiency because of concentration quenching of a semiconductor phosphor microparticle.
The present invention was devised in light of the aforementioned circumstances, and it is an object of the present invention to provide a light emitting device and an image display device having high luminous efficiency.
As a result of diligent efforts about a light emitting device having high luminous efficiency, the inventors of the present invention revealed that a light emitting device having high luminous efficiency can be provided by having a light emitting element, and a semiconductor phosphor microparticle of a core/shell structure having a shell part that absorbs at least a part of the light emitted by the light emitting element.
According to the present invention, it is possible to provide a light emitting device having high luminous efficiency, and an image display device using the same.
A light emitting device of the present invention includes a light emitting element, and a semiconductor phosphor microparticle having a core/shell structure having a core part and a shell part that covers the core part and absorbs at least a part of the light emitted by the light emitting element.
Preferably, in the light emitting device of the present invention, bandgap energy of the shell part of the semiconductor phosphor microparticle is smaller than light energy emitted from the light emitting element.
Preferably, in the light emitting device of the present invention, bandgap energy of the shell part of the semiconductor phosphor microparticle is larger than bandgap energy of the core part.
Preferably, the light emitting device of the present invention includes two or more kinds of semiconductor phosphor microparticles having different peak wavelengths of an emission spectrum. In this case, more preferably, bandgap energy of the shell part of the semiconductor phosphor microparticle is larger than bandgap energy of the core part of any of the semiconductor phosphor microparticles.
Preferably, in the light emitting device of the present invention, a half-value width of an emission spectrum of the core part of the semiconductor phosphor microparticle is 80 nm or more.
Further preferably, in the light emitting device of the present invention, standard deviation of particle diameter distribution of the core part of the semiconductor phosphor microparticle is 20% or more of mean particle diameter of the core part of the semiconductor phosphor microparticle.
Preferably, in the light emitting device of the present invention, the core part of the semiconductor phosphor microparticle is a group II-VI semiconductor material or a group III-V semiconductor material. In this case, more preferably, the core part of the semiconductor phosphor microparticle is formed of ternary or higher mixed crystal. Further preferably, the core part of the semiconductor phosphor microparticle is either of InP, InGaP, InN, and InGaN.
Preferably, in the light emitting device of the present invention, the shell part of the semiconductor phosphor microparticle is ZnSe or SiC.
Preferably, in the light emitting device of the present invention, the semiconductor phosphor microparticle has a plurality of shell parts.
Preferably, in the light emitting device of the present invention, the semiconductor phosphor microparticle is covered with a translucent member.
Preferably, in the light emitting device of the present invention, the light emitting element is a semiconductor light emitting diode element or a semiconductor laser diode element. In this case, preferably, the semiconductor light emitting diode element or the semiconductor laser diode element is formed of a GaN-based material.
In the light emitting device of the present invention, the light emitting element may be an organic electroluminescence element.
Preferably, in the light emitting device of the present invention, an emission spectrum of the light emitting element has a peak wavelength in the range of 420 to 480 nm.
Further, in the light emitting device of the present invention, an emission spectrum of the light emitting element may have a peak wavelength in the range of 350 to 420 nm.
Preferably, the light emitting device of the present invention includes a blue luminescent light emitting element, and a red luminescent semiconductor phosphor microparticle and a green luminescent semiconductor phosphor microparticle.
Further, the light emitting device of the present invention may include a UV to blue-violet luminescent light emitting element, a blue luminescent semiconductor phosphor microparticle, a green luminescent semiconductor phosphor microparticle and a red luminescent semiconductor phosphor microparticle.
The present invention also provides an image display device including: a light emitting element, and a semiconductor phosphor microparticle having a core/shell structure having a core part and a shell part that covers the core part and absorbs at least a part of light emitted by the light emitting element.
Preferably, in the image display device of the present invention, a half-value width of an emission spectrum of the core part of the semiconductor phosphor microparticle is 40 nm or less.
Preferably, in the image display device of the present invention, standard deviation of particle diameter distribution of the core part of the semiconductor phosphor microparticle is 15% or less of mean particle diameter of the core part of the semiconductor phosphor microparticle.
Preferably, the image display device of the present invention includes a white light emitting device including the light emitting element and the semiconductor phosphor microparticle, and a color filter.
Preferably, the image display device of the present invention also includes the light emitting element, and a wavelength conversion member including the semiconductor phosphor microparticle.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a section view schematically showing a light emitting device 1 according to a first preferred example of the present invention.
FIG. 2 is a section view schematically showing a light emitting device 21 according to a second preferred example of the present invention.
FIG. 3 is a section view schematically showing a light emitting device 41 according to a third preferred example of the present invention.
FIG. 4 is a section view schematically showing one example of semiconductor phosphor microparticles 3, 4 having a core/shell structure in the present invention.
FIG. 5 is an exploded perspective view conceptually showing an image display device 101 of a first preferred example of the present invention.
FIG. 6 is an exploded perspective view showing a wavelength conversion part 104 in an image display device 101 in the example shown in FIG. 5 in an enlarged manner.
FIG. 7 is a graph showing a transmission spectrum of a red color filter, a transmission spectrum of a green color filter, and a transmission spectrum of a blue color filter of color filters used in the image display device of the present invention.
FIG. 8 is an exploded perspective view schematically showing an image display device 121 according to a second preferred example of the present invention.
FIG. 9 is an exploded perspective view showing a wavelength conversion part 123 in image display device 121 in the example shown in FIG. 8 in an enlarged manner.
FIG. 10 is a schematic view schematically showing a wavelength conversion member 136 in the example shown in FIG. 9.
FIG. 11 is an exploded perspective view schematically showing an image display device 151 in a third preferred example of the present invention.
FIG. 12 is an exploded perspective view schematically showing an image display device 161 in a fourth preferred example of the present invention.
FIG. 13 is an exploded perspective view schematically showing an image display device 171 in a fifth preferred example of the present invention.
FIG. 14 is a perspective view showing a wavelength conversion part 172 in an image display part 173 in image display device 171 in the example shown in FIG. 13 in an enlarged manner.
FIG. 15 is an exploded perspective view schematically showing an image display device 181 in a sixth preferred example of the present invention.
FIG. 16 is a perspective view showing a wavelength conversion part 182 in an image display part 183 in image display device 181 in the example shown in FIG. 15 in an enlarged manner.
FIG. 17 is an absorption-emission spectrum of an InP/ZnS semiconductor phosphor microparticle synthesized in Comparative production example 1r.
FIG. 18 is an absorption-emission spectrum of an InP/ZnS semiconductor phosphor microparticle synthesized in Production example 1r.
FIG. 19 is a graph showing dependency of luminous efficiency on absorptance of an InP/ZnS semiconductor phosphor microparticle synthesized in Comparative production example 1r and an InP/ZnSe semiconductor phosphor microparticle synthesized in Production example 1r.
FIG. 20 is a graph showing shell part bandgap energy and luminous efficiency in a light emitting device of the present invention.
FIG. 21 is a graph showing shell part bandgap energy and luminous efficiency in a light emitting device of the present invention.
FIG. 22 is a graph showing shell part bandgap energy and luminous efficiency in a light emitting device of the present invention.
FIG. 23 is a graph showing a core part material and luminous efficiency in a light emitting device of the present invention.
FIG. 24 is a graph showing a half-value width and a color rendering property index Ra of a phosphor in a light emitting device of the present invention.
FIG. 25 is a graph showing the number of phosphor and luminous efficiency in a light emitting device of the present invention.
FIG. 26 is a graph showing the number of phosphor and color rendering property index Ra in a light emitting device of the present invention.
FIG. 27 is a graph showing shell part bandgap energy and brightness in an image display device of the present invention.
FIG. 28 is a graph showing shell part bandgap energy and brightness in an image display device of the present invention.
FIG. 29 is a graph showing shell part bandgap energy and brightness in an image display device of the present invention.
FIG. 30 is a graph showing a core part material and brightness in an image display device of the present invention.
FIG. 31 is a graph showing a half-value width of phosphor and an NTSC ratio in an image display device of the present invention.
FIG. 32 is a graph showing the number of phosphor and an NTSC ratio in an image display device of the present invention.



DETAILED DESCRIPTION OF THE INVENTION
<Light Emitting Device>
A light emitting device in the present invention basically includes a light emitting element, and a semiconductor phosphor microparticle having a core/shell structure, and is characterized in that excitation light of a light source is absorbed in a shell part of the semiconductor phosphor microparticle. With such a configuration, the present invention is able to provide an excellent light emitting device realizing both color rendering property and luminous efficiency.
In the light emitting device of the present invention, as a light emitting element, a semiconductor light emitting element such as a semiconductor light emitting diode element or a semiconductor light emitting laser diode element, an organic electroluminescence element, an inorganic electroluminescence element, a discharge lamps such as xenon lamp, a fluorescent lamp and the like may be used. In the light emitting device of the present invention, at least a part of luminescence from the light emitting element is absorbed by a shell part of the semiconductor phosphor microparticle. The semiconductor phosphor microparticle having absorbed the light emits light having a wavelength different from that of the absorbed light from a core part. As a result, the light emitting device emits light in which transmitted light of the light emitting element and fluorescent light of the semiconductor phosphor microparticle are mixed.
FIG. 1 is a section view schematically showing a light emitting device 1 of a preferred first example of the present invention. The light emitting device 1 in the example shown in FIG. 1 shows an example in which combination of a semiconductor light emitting diode element 2 as a light emitting element, and semiconductor phosphor microparticles 3, 4 are used. In light emitting device 1 in the example shown in FIG. 1, semiconductor light emitting diode element 2 and a resin frame 6 are placed on a printed circuit board 5 serving as a base. Inside resin frame 6, a mold resin 7 of a translucent resin in which a plurality of semiconductor phosphor microparticles 3, 4 are dispersed is packed to form a translucent member, and semiconductor light emitting diode element 2 is sealed by this mold resin 7. At least a part of the light emitted from semiconductor light emitting diode element 2 is absorbed by shell parts of semiconductor phosphor microparticles 3, 4. Semiconductor phosphor microparticles 3, 4 having absorbed the light will emit light having a wavelength different from that of the absolved light from core parts. As a result, light emitting device 1 emits the light in which transmitted light of semiconductor light emitting diode element 2 and fluorescent light of semiconductor phosphor microparticles 3, 4 are mixed.
Semiconductor light emitting diode element 2 in the example shown in FIG. 1 is one of the elements that utilize luminescence characteristics of a semiconductor material having a property of emitting light at the time of rebinding of an electron and a hole. As shown in FIG. 1, for example, semiconductor light emitting diode element 2 has such a structure that a p-side electrode 9 is disposed on the upper face side of a semiconductor active layer 8 and a n-side electrode 10 is disposed on the lower face side of semiconductor active layer 8 in such a manner that they sandwich semiconductor active layer 8. N-side electrode 10 is electrically connected to an n electrode part 11 extending from the top face to the back face of printed circuit board 5 via an adhesive 12 having conductivity. Also p-side electrode 9 is electrically connected to a p electrode 13 extending from the top face to the back face of printed circuit board 5 separately from n electrode part 11 as described above, via a metal wire 14.
FIG. 2 is a section view schematically showing a light emitting device 21 of a second preferred example of the present invention. The part having a configuration similar to that of light emitting device 1 in the example shown in FIG. 2 is denoted by the same reference numeral, and description thereof will be omitted. Light emitting device 21 in the example shown in FIG. 2 shows an example in which combination of a semiconductor light emitting laser diode element 22 as a light emitting element and semiconductor phosphor microparticles 3, 4 is used. In the example shown in FIG. 2, a wavelength conversion member 23 is disposed on a light outgoing face of packaged semiconductor light emitting laser diode element 22. Wavelength conversion member 23 includes a plurality of semiconductor phosphor microparticles 3, 4 dispersed in a translucent member 24. At least a part of the light emitted from semiconductor light emitting laser diode element 22 is absorbed in shell parts of semiconductor phosphor microparticles 3, 4. Semiconductor phosphor microparticles 3, 4 having absorbed light will emit light having a wavelength different from that of the absorbed light from core parts. As a result, light emitting device 21 emits light in which transmitted light of semiconductor light emitting laser diode element 22 and fluorescent light of semiconductor phosphor microparticles 3, 4 are mixed.
Likewise the semiconductor light emitting diode element described above, semiconductor light emitting laser diode element 22 in the example shown in FIG. 2 is one of the elements that utilize luminous characteristics of a semiconductor material having a property of emitting light at the time of rebinding of an electron and a hole. As shown in FIG. 2, in semiconductor light emitting laser diode element 22, a semiconductor laser chip 25 is disposed on a heat sink system 26. Semiconductor laser chip 25 has such a structure that a semiconductor active layer which is a light emitting part is disposed in such a manner that semiconductor laser chip 25 is sandwiched between a p-type semiconductor and a n-type semiconductor, and further between a p-type electrode and a n-type electrode. Semiconductor laser chip 25 is jointed to heat sink system 26 via a Si submount 27. A solder is used for joining semiconductor laser chip 25 and Si submount 27, and a silver paste or a solder is used for joining Si submount 27 and heat sink system 26. Thereafter, an electrode of semiconductor laser chip 25 is electrically connected to terminal pins 28, 29 of the heat sink system via a gold wire 30. Then a wind cap 31 having a glass window through which laser light outgoes is joined to heat sink system 26.
As the semiconductor light emitting element such as semiconductor light emitting diode element 2 (FIG. 1) or semiconductor light emitting laser diode element 22 (FIG. 2) as described above, those conventionally known and having general compositions, for example, a GaN-based semiconductor light emitting element, a ZnSe-based semiconductor light emitting element, a SiC-based semiconductor light emitting element and the like may be used. Among these, a GaN-based semiconductor light emitting element is particularly preferably used because a light emitting device having high luminous efficiency and high practicability is realizable.
In the light emitting device of the present invention, it is preferred to use a semiconductor light emitting element having a peak wavelength of an emission spectrum in a wavelength range of 420 to 480 nm. This is because when the peak wavelength of the emission spectrum of the semiconductor light emitting element falls within a wavelength range of 420 to 480 nm, transmitted light of the light emitting element can be used directly as blue light of the light emitting device (and an image display device as will be described later). In the present invention, it is preferred to use a semiconductor light emitting element having a peak wavelength of an emission spectrum in a wavelength range of 440 to 460 nm. The semiconductor light emitting element having the peak wavelength of the emission spectrum in a wavelength range of 440 to 460 nm realizes an image display device having improved color reproducibility and luminous efficiency because wavelength integrity with the blue color filter (see FIG. 7) is high when it is applied to in an image display device as will be described later.
The semiconductor light emitting element in the present invention may have a peak wavelength of an emission spectrum in a wavelength range of 390 to 420 nm. A GaN-based semiconductor light emitting element which is a preferred semiconductor light emitting element in the present invention is excellent in that a light emitting element having high luminous efficiency in a wavelength range of 390 to 420 nm can be easily fabricated.
FIG. 3 is a section view schematically showing a light emitting device 41 of a third preferred example of the present invention. The part having a similar configuration as that of light emitting devices 1, 21 in the examples shown in FIG. 1 and FIG. 2 is denoted by the same reference numeral, and description thereof will be omitted. Light emitting device 41 in the example shown in FIG. 3 shows an example in which combination of an organic electroluminescence element 42 as a light emitting element and semiconductor phosphor microparticles 3, 4 is used. Light emitting device 41 in the example shown in FIG. 3 includes organic electroluminescence element 42 fabricated on a substrate 44, and a wavelength conversion member 43 fabricated on the back face of substrate 44. Wavelength conversion member 43 is formed of a translucent member 45 in which semiconductor phosphor microparticles 3, 4 are dispersed. At least a part of the light emitted from organic electroluminescence element 42 is absorbed by shell parts of semiconductor phosphor microparticles 3, 4. Semiconductor phosphor microparticles 3, 4 having absorbed light will emit light having a wavelength different from that of absorbed light from core parts. As a result, light emitting device 41 emits light in which transmitted light of organic electroluminescence element 42 and fluorescent light of semiconductor phosphor microparticles 3, 4 are mixed.
Organic electroluminescence element 42 in the example shown in FIG. 3 has such a structure that an anode 46 is disposed on substrate 44, and a hole injection layer 47, a hole transport layer 48, a light emitting layer 49, an electron transport layer 50, an electron injection layer 51, and a cathode 52 are sequentially formed on anode 46.
Light emitting layer 49 in organic electroluminescence element 42 is a layer having a function of emitting light by rebinding of a hole and an electron by receiving a hole from hole transport layer 48 and an electron from electron transport layer 50 at the time of application of voltage. Light emitting layer 49 preferably contains a host material, and a dopant formed of a phosphorescence material. As the host material, a charge transport material (generic term of electron transport material and hole transport material) is preferred, and further preferably a hole transport material and an electron transport material are contained.
Energy level of the lowest multiplet excited state of the host material is preferably larger than energy level of the lowest multiplet excited state of a dopant material. By co-vapor deposition of the host material and the dopant material, it is possible to suitably form a light emitting layer in which the host material is doped with the dopant material. Concrete examples of the host material include those having a pyrene skeleton, those having a carbazole skeleton, those having a diarylamine skeleton, those having a pyridine skeleton, those having a pyrazine skeleton, those having a triazine skeleton, and those having an arylsilane skeleton.
Generally, the phosphorescence material contained in the light emitting layer is preferably a complex containing a transition metal atom or a lanthanoid atom. One kind or combination of two or more kinds of phosphorescence materials may be used. Examples of the transition metal atom include, but are not limited to, preferably ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium and platinum, and more preferably rhenium, iridium and platinum. As a lanthanoid atom, lanthanum, cerium, praseodymium, neodymium, samarium, europium, cadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutecium are recited. Among these lanthanoid atoms, neodymium, europium and cadolinium are preferred. Concrete examples of a phosphorescence material satisfying the above condition include FIrpic: bis[2-(4,6-difluorophenyl)pyridinato]picolinato irridium (III), FIr6: bis[2-(4′, 6′-difluorophenyl)pyridinate-N,C2′]tetrakis (1-pyrazolyl)borate, and Ir(ppy)3: trisphenyl pyridinato irridium (III).
Hole injection layer 47 and hole transport layer 48 are layers having a function of receiving a hole from an anode or anode side and transporting it to the cathode side. Hole injection layer 47 and hole transport layer 48 are preferably layers that include concretely as a hole transport material, carbazole derivative, triazole derivative, oxazole derivative, oxadiazole derivative, imidazole derivative, polyaryl alkane derivative, pyrazoline derivative, pyrazolone derivative, phenylene diamine derivative, aryl amine derivative, amine substituted chalcone derivative, stylyl anthracene derivative, fluorenone derivative, hydrazone derivative, stilbene derivative, silazane derivative, aromatic tertiary amine compound, styryl amine compound, aromatic dimethylidene-based compound, porphyrin-based compound, organic silane derivative, carbon and the like.
Electron injection layer 51 and electron transport layer 50 are layers having a function of receiving an electron from a cathode or a cathode side and transporting it to the anode side. The electron injection layer and the electron transport layer are preferably layers containing, concretely as an electron transport material, various metal complexes represented by metal complexes of triazole derivative, oxazole derivative, oxadiazole derivative, imidazole derivative, fluorenone derivative, anthraquinodimethane derivative, anthorone derivative, diphenylquinone derivative, thiopyran dioxide derivative, carbodiimide derivative, fluorenylidene methane derivative, distyryl pyrazine derivative, aromatic tetracarbonate anhydride such as naphthalene and perylene, phthalocyanine derivative, 8-quinolinol derivative, and metal phthalocyanine, metal complexes having a ligand of benzoxazole or benzothiazole, organic silane derivative and so on. Among these, an electron transport layer containing an aromatic hetero cyclic compound having at least one hetero atom in the molecule as an electron transport material is preferred. The aromatic hetero cyclic compound refers to a hetero compound having aromaticity, and pyridine, pyrazine, pyrimidine, pyridazine, triazine, pyrazole, imidazole, benzimidazole, triazole, thiazole, benzothiazole, isothiazole, benzisothiazole and thiadiazole or condensed rings thereof are recited.
Usually, shape, structure, size and the like of anode 46 are not particularly limited as far as a function as an electrode that supplies hole injection layer 47 with a hole is realized, and a known electrode material may be appropriately selected depending on use application and purpose of the organic electroluminescence element. Material of anode 46 is preferably a transparent material. In this case, luminescence of light emitting layer 49 from the anode side can be taken out without any loss.
As a material forming anode 46, for example, metal, alloy, metal oxide, and conductive compound or mixtures thereof are preferably recited, a material having a work function of 4.0 eV or higher is preferred. Concrete examples of the anode material include tin oxide doped with antimony or fluorine (ATO, FTO), conductive metal oxides such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO), metals such as gold, silver, chromium and nickel, mixtures or laminates of such metal and conductive metal oxide, inorganic conductive substances such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene and polypyrrole, and laminates of these and ITO. Among these, conductive metal oxides are preferred, and in particular, from the view points of productivity, high conductivity, transparency and the like, ITO is preferred.
Also, a thin film transistor (TFT) may be incorporated in anode 46. This case is preferred in fabricating an image display device using an organic electroluminescence element because ON/OFF can be controlled using the TFT.
Usually, shape, structure, size and the like of cathode 52 are not particularly limited as far as a function as an electrode that injects an electron into electron injection layer 51 is realized, and a known electrode material may be appropriately selected depending on use application and purpose of the light emitting element.
As a material forming cathode 52, for example, metal, alloy, metal oxide, and conductive compound or mixtures thereof are recited, a material having a work function of 4.5 eV or lower is preferred. Concrete examples include alkaline metals (e.g., Li, Na, K, Cs and so on), alkaline earth metals (e.g., Mg, Ca and so on), gold, silver, lead, aluminum, sodium-potassium alloy, lithium-aluminum alloy, magnesium-silver alloy, and rare earth metals such as indium and ytterbium. These may be used singly, however, two or more kinds are preferably used from the view point of realizing both stability and electron injection property.
Substrate 44 has a function as a supporting base body of the organic electroluminescence element. Also substrate 44 is preferably a substrate that will not scatter or attenuate the light emitted from light emitting layer 49. Concrete examples include inorganic materials such as yttrium stabilized zirconia (YSZ) and glass, and organic materials including polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphtharate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycyclooleofine, norbornene resin, and poly(chlorotrifluoro ethylene).
In the light emitting device of the present invention, from the view point of ability of efficiently exciting green to red luminescent semiconductor phosphor microparticles, the emission wavelength of the organic electroluminescence element is preferably 520 nm or less. From the view point that transmitted light of the light emitting element can be directly used as blue light of the light emitting device (and later-described image display device), the emission wavelength of the organic electroluminescence element is preferably 420 nm or higher. This case is advantageous in that the structure of the light emitting device is simplified and production is facilitated. More preferably, as an organic electroluminescence element in the present invention, it is preferred to have a peak wavelength of an emission spectrum in a wavelength range of 440 to 460 nm. This realizes an image display device having improved color reproducibility and luminous efficiency because wavelength integrity with the blue color filter (see FIG. 7) is high when it is applied in an image display device as will be described later.
Next, a semiconductor phosphor microparticle used in the present invention will be described in detail.
The term semiconductor phosphor microparticle in the present invention refers to that having a function of absorbing at least a part of excitation light and emitting light having a wavelength different from that of the excitation light. The semiconductor phosphor microparticle in the present invention is formed of a semiconductor microcrystal having a particle size of a core part which is a light emitting part of about several nanometers. Such a semiconductor microparticle is also called a colloidal particle, nanoparticle, or quantum dot. In the following a semiconductor phosphor microparticle in the present invention will be described.
The semiconductor phosphor microparticle in the present invention has a core/shell structure and is characterized by absorbing excitation light in a shell part. Here, the term core/shell structure refers to a structure in which at least a part of a surface of a core part is covered with a shell part. FIG. 4 is a section view schematically showing one example of semiconductor phosphor microparticles 3, 4 having a core/shell structure in the present invention. The semiconductor phosphor microparticle having a core/shell structure has such a structure that at least a part of a surface of a core part 61 formed of a semiconductor material is covered with a shell part 62. Here, core part 61 is a light emitting part emitting light as a result of rebinding of an electron and a hole. Shell part 62 is formed of a material different from that of core part 61. The semiconductor phosphor microparticle in the present invention absorbs excitation light in shell part 62 upon irradiation with excitation light. An electron and a hole are generated as shell part 62 absorbs light. At least a part of the generated electrons and holes move to a core part where they rebind to emit light. Shell part 62 also has a protecting function for protecting adverse affect exerted on core part 61 from the external world. Preferably, shell part 62 has bandgap energy higher than that of core part 61, and has a function of confining an electron and a hole of a core part. This case is advantageous in that the loss of electrons and holes due to non-luminous transition can be reduced, and luminous efficiency is improved.
To the surface of the semiconductor phosphor microparticle in the present invention, an organic compound 63 may be bound. Organic compound 63 is excellent in that a function of controlling dispersibility in dispersing semiconductor microparticles into liquid or solid can be added. Organic compound 63 may further have a function of confining an electron inside a semiconductor microparticle, a function of protecting a semiconductor microparticle from adverse affect received from the external world, and a function of suppressing aggregation of semiconductor microparticles.
The core/shell structure of semiconductor phosphor microparticle in the present invention may have a multi-shell structure made up of a plurality of shell parts. As a concrete example of the multi-shell structure, a core/shell/shell structure in which another shell part B is formed on outer surface of shell part A covering the core part is exemplified. This case is preferred in that durability of the semiconductor phosphor microparticle having shell part B is further improved because shell part B protects shell part A. The core/shell structure of semiconductor phosphor microparticle in the present invention may have a shell/core/shell structure in which there is shell part A in the center, a core part is formed on the surface of shell part A, and shell part B is further formed on the outer surface of the core part. In this case, since the core part is surrounded by shell parts A, B, an electron confining effect is exerted more effectively than by a core/shell structure, and luminous efficiency can be further improved.
A method of examining a structure of the semiconductor phosphor microparticle may be any known method, and for example, direct observation by means of a transmission electron microscope (TEM) is exemplified.
Shape of the semiconductor phosphor microparticle in the present invention may be any shape, and for example, sphere, column, cube, regular tetrahedron and the like are exemplified. Among these, a sphere is particularly preferred because of a small proportion of surface area, relative to the volume. When the proportion of surface area is small, probability of non-luminous transition in the surface is small, so that a semiconductor phosphor microparticle having high luminous efficiency is obtained.
The semiconductor phosphor microparticle in the present invention is characterized by capability of controlling emission wavelength. This is because a quantum confining effect arising when a particle size of semiconductor crystal is reduced to twice or less the Bohr radius is utilized. As for a core part of a semiconductor phosphor microparticle, bandgap energy of the core part varies due to the quantum confining effect depending on the particle diameter. Therefore, it is advantageous in that emission wavelength can be controlled by controlling bandgap energy using particle diameter. Using a mixed crystal in the semiconductor microparticle core part is further preferred because emission wavelength can be controlled also by the mixed crystal ratio.
Luminous wavelength of the semiconductor phosphor microparticle in the present invention is not particularly limited, but is preferably in a visible light wavelength range. This is because when a semiconductor phosphor microparticle having an emission wavelength in a visible light wavelength range is used, a light emitting device (and image display device as will be described later) having excellent characteristics can be realized. As concrete examples of emission wavelength of the semiconductor phosphor microparticle, a wavelength range of 420 to 490 nm for a blue luminescent phosphor, a wavelength range of 500 to 565 nm for a green luminescent phosphor, a wavelength range of 565 to 585 nm for a yellow luminescent phosphor, and a wavelength range of 595 to 720 nm for a red luminescent phosphor are exemplified.
As a method of examining a peak wavelength of an emission spectrum of a semiconductor phosphor microparticle, a photoluminescence measurement, a cathode luminescence measurement, an electroluminescence measurement and the like are exemplified. By measuring the emission spectrum according to such measurement, a peak wavelength can be determined.
A half-value width of an emission spectrum of a semiconductor phosphor microparticle in the present invention is not particularly limited, but a wider half-value width is preferred from the view point of production of a light emitting device. This is because when the half-value width of the emission spectrum is large, a light emitting device having high color rendering property can be realized with less kinds of semiconductor phosphor microparticles. Concretely, the half-value width of the emission spectrum is preferably 40 nm or more, more preferably 60 nm or more, and particularly preferably 80 nm or more.
As a method of examining the half-value width of the emission spectrum of a semiconductor phosphor microparticle, photoluminescence measurement, cathode luminescence measurement, electroluminescence measurement and the like are exemplified. By the measuring the emission spectrum according to such measurement, a half-value width of an emission peak can be calculated.
The semiconductor phosphor microparticle in the present invention absorbs at least a part of the excitation light emitted from a light source, in a shell part. As a result, the semiconductor phosphor microparticle emits light. As a method of examining absorption characteristics of the semiconductor phosphor microparticle, measurement of an absorption spectrum by a spectrophotometer or the like is exemplified.
Band gap of a core part of the semiconductor phosphor microparticle of the present invention can assume any value, but is preferably 2.9 eV or less. When the bandgap of the core part of the semiconductor phosphor microparticle exceeds 2.9 eV, luminosity factor of human greatly decreases, to lead a problem that characteristics of the light emitting device and the image display device are impaired. As a method of examining bandgap of a core part, a method of determining by calculation from the material and mean particle diameter of the core part, and a method of determining from emission and absorption characteristics are recited.
Mean particle diameter (diameter) of a core part of the semiconductor phosphor microparticle in the present invention is preferably twice or less the Bohr radius. When the mean particle diameter (diameter) of the core part is twice or less the Bohr radius, quantum confining effect is obtained, and bandgap energy can be varied. Here, Bohr radius of InP, InN and CdSe is 8.3 nm, 7.0 nm, and 4.9 nm, respectively.
As a method of determining a mean particle diameter of a core part of the semiconductor phosphor microparticle, dynamic scattering method (DLS), a method of measuring by a powder X-ray diffraction (XRD: X-ray diffraction) apparatus, and direct observation by a transmission electron microscope are exemplified. In the powder X-ray diffraction apparatus, mean particle diameter of crystal can be determined from the obtained half-value width of diffraction peak of the crystal using a Scherrer formula. In a transmission electron microscope, mean particle diameter of crystals can be examined by measuring particle diameters of arbitrary 20 particles, and calculating a mean particle diameter through statistical processing.
As a method of adjusting mean particle diameter of a core part of the semiconductor phosphor microparticle, a conventionally known classification method may be used, and as such a classification method, for example, electrophoresis method, size selection precipitation method, light-assisted etching method and so on are recited.
Variation in mean particle diameter of a core part of the semiconductor phosphor microparticle in the present invention will largely influence on the half-value width of the emission spectrum. Concretely, when the variation in mean particle diameter is large, the half-value width of the emission spectrum increases. Therefore, it is necessary to control the particle diameter distribution so that requested the half-value width of the emission spectrum is achieved.
From the view point of improving the color rendering property of the light emitting device of the present invention, standard deviation of particle diameter distribution of a core part of the semiconductor phosphor microparticle is preferably 15% or higher, and more preferably 20% or higher of the mean particle diameter of the core part of the semiconductor phosphor microparticle. This is because when standard deviation of the particle diameter distribution of the core part of the semiconductor phosphor microparticle is large, an emission spectrum becomes continuous, and the color rendering property tends to increase.
As the method of examining particle diameter distribution of a core part of the semiconductor phosphor microparticle, any appropriate known method may be used without any limitation, and dynamic scattering method, and direct observation by means of a transmission electron microscope can be exemplified. As a method of measuring particle diameter distribution using a transmission electron microscope, standard deviation of mean particle diameter of a core part can be examined by measuring particle diameters of for example, 20 particles.
As a method of adjusting particle diameter distribution of the core part of the semiconductor phosphor microparticle, a conventionally known classification method can be used as is the case with control of mean particle diameter.
Band gap energy of a shell part of the semiconductor phosphor microparticle in the present invention is preferably smaller than light energy of light emitted from the light emitting element (excitation light). This is because the excitation light is absorbed in the shell part.
Band gap energy of the shell part of the semiconductor phosphor microparticle in the present invention is preferably larger than bandgap energy of the core part. This allows efficient transport of electrons and holes to the core part and suppression of reabsorption of fluorescence emitted from the core part by the shell part. When the shell part absorbs fluorescence emitted from the core part, loss of fluorescence by self absorption arises to cause deterioration in luminous efficiency.
As a method of examining bandgap of the shell part of the semiconductor phosphor microparticle, a method of calculating from the material of the core part, a method of determining from emission-absorption characteristics and the like are recited.
A shape of the shell part of the semiconductor phosphor microparticle in the present invention may be any shape, but it is preferred to cover the entire surface of the core part. This is because high luminous efficiency is realized in a semiconductor phosphor microparticle having a core/shell structure in which the entire surface of the core part is covered. This is because a defect existing in the surface of the core part is inactivated by being covered with the shell part.
The core part of the semiconductor phosphor microparticle in the present invention is characterized by being formed of a semiconductor material. As a material of such a core part of the semiconductor phosphor microparticle, for example group IV semiconductor material, group IV-IV semiconductor material, group III-V semiconductor material, group II-VI semiconductor material, group I-VIII semiconductor material, and group IV-VI semiconductor material are exemplified. Among these, the core part of the semiconductor phosphor microparticle is preferably formed of a group II-VI semiconductor material or a group III-V semiconductor material because of the high chemical stability and excellent environmental resistance.
As the number of crystals mixed in a core part of the semiconductor phosphor microparticle in the present invention, a simple substance semiconductor formed of one kind of element, a binary compound semiconductor formed of two kinds of elements, and a mixed crystal semiconductor formed of three or more kinds of elements may be used. However, from the view point of improving the luminous efficiency of the light emitting device, the core part of the semiconductor phosphor microparticle is preferably formed of a direct transition-type semiconductor material. A core part of the semiconductor phosphor microparticle is preferably the one that emits visible light. More preferably, a core part of the semiconductor phosphor microparticle is formed of a mixed crystal semiconductor material because the peak wavelength of the emission spectrum can be readily controlled. On the other hand, from the view point of easiness of production, a core part of the semiconductor phosphor microparticle is preferably formed of quaternary or less mixed crystal. From the view point of controllability of the peak wavelength of the emission spectrum, the core part of the semiconductor phosphor microparticle in the present invention is particularly preferably a semiconductor phosphor microparticle formed of ternary or more mixed crystal.
As a semiconductor phosphor microparticle formed of a binary compound used as the core part of the semiconductor phosphor microparticle, for example, InP, InN, InAs, GaAs, CdSe, CdTe, ZnSe, ZnTe, PbS, PbSe, PbTe, CuCl and so on can be recited. However, from the view point of safety on human body and environmental load, InP or InN is more preferred used. From the view point of easiness of production, CdSe or CdTe is preferably used. As a ternary mixed crystal semiconductor phosphor microparticle, for example, InGaP, AlInP, InGaN, AlInN, ZnCdSe, ZnCdTe, PbSSe, PbSTe, PbSeTe and so on can be recited, and from the view point of capability of fabricating a semiconductor phosphor microparticle which is environment-friendly material and is unsusceptible to the external world, it is preferred to use a group III-V mixed crystal semiconductor phosphor microparticle formed of InGaP or InGaN.
The shell part of the semiconductor phosphor microparticle in the present invention is characterized by being formed of a semiconductor material. As such a shell part material, for example, a group IV semiconductor material, a group IV-IV semiconductor material, a group III-V compound semiconductor material, a group II-VI compound semiconductor material, a group I-VIII compound semiconductor material, a group IV-VI compound semiconductor material and the like are exemplified. As for the number of mixed crystals, a simple substance semiconductor formed of one kind of element, a binary compound semiconductor formed of two kinds of elements, and a mixed crystal semiconductor formed of three or more kinds of elements may be used. However, from the view point of improving the luminous efficiency of the light emitting device, a semiconductor material having higher bandgap energy than the core part is preferred as a material of the shell part. From the view point of the protecting function of the core part, a group III-V compound semiconductor material having strong bonding power of atoms and high chemical stability is preferred. On the other hand, from the view point of easiness of production, it is preferred to use a semiconductor phosphor microparticle formed of quaternary or less mixed crystal.
As a semiconductor phosphor microparticle formed of a binary compound used as such a semiconductor phosphor microparticle shell part, for example, AlP, GaP, AlN, GaN, AlAs, ZnO, ZnS, ZnSe, ZnTe, MgO, MgS, MgSe, MgTe, CuCl and so on can be recited. However, from the view point of safety on human body and environmental load, it is preferred to use AlP, GaP, AlN, GaN, ZnO, ZnS, ZnSe, ZnTe, MgO, MgS, MgSe, MgTe, CuCl, or SiC. As a semiconductor phosphor microparticle shell part of ternary mixed crystal, for example, AlGaN, GaInN, ZnOS, ZnOSe, ZnOTe, ZnSSe, ZnSTe, ZnSeTe and so on are recited, and from the view point of capability of fabricating a semiconductor phosphor microparticle which is environment-friendly material and is unsusceptible to the external world, it is preferred to use AlGaN, GaInN, ZnOS, ZnOTe, or ZnSTe.
As a method of measuring a material constituting the core part and the shell part of the semiconductor phosphor microparticle, powder X-ray diffraction method, electron beam diffraction method, X-ray photoelectron spectrometry and the like are exemplified.
Outside the shell part of the semiconductor phosphor microparticle in the present invention may be covered with an organic compound. This case is advantageous in that a function such as dispersibility may be imparted to the semiconductor phosphor microparticle by the organic compound. Also the organic compound may have a function of confining an electron inside a semiconductor phosphor microparticle, a function of protecting a semiconductor phosphor microparticle from adverse affect received from the external world, and a function of suppressing aggregation of semiconductor phosphor microparticles. As such an organic compound, an organic compound consisting of an alkyl group which is a functional part, and a binding part for a shell part of a semiconductor phosphor microparticle is preferred, and as concrete examples, an amine compound, phosphine compound, phosphine oxide compound, thiol compound, fatty acid and the like are exemplified. Examples of the phosphine compound include tributylphosphine, trihexylphosphine, and trioctylphosphine. Examples of the phosphine oxide compound include 1-dichlorophosphinol heptane, 1-dichlorophosphinol nonane, t-butyl phosphonic acid, tetradecyl phosphonic acid, dodecyldimethylphosphine oxide, dioctylphosphine oxide, didecylphosphine oxide, tributylphosphine oxide, tripentylphosphine oxide, trihexylphosphine oxide, and trioctylphosphine oxide. Examples of the thiol compound include tributyl sulfide, trihexyl sulfide, trioctyl sulfide, 1-heptyl thiol, 1-octyl thiol, 1-nonane thiol, 1-decane thiol, 1-undecane thiol, 1-dodecane thiol, 1-tridecane thiol, 1-tetradecane thiol, 1-pentadecane thiol, 1-hexadecane thiol, 1-octadecane thiol, dihexyl sulfide, diheptyl sulfide, dioctyl sulfide, and dinonyl sulfide. Examples of the amine compound include heptyl amine, octyl amine, nonyl amine, decyl amine, undecyl amine, dodecyl amine, tridecyl amine, tetradecyl amine, hexadecyl amine, octadecyl amine, oleyl amine, dioctyl amine, tributyl amine, tripentyl amine, trihexyl amine, triheptyl amine, trioctyl amine, and trinonyl amine. Examples of the fatty acid include lauric acid, myristic acid, palmitic acid, stearic acid and oleic acid.
As a method of examining an organic compound material covering the semiconductor phosphor microparticle, infrared spectrometry (IR), nuclear magnetic resonance (NMR) and the like are exemplified.
A method of synthesizing a semiconductor phosphor microparticle in the present invention may be a conventionally known method, and for example, a vapor phase synthetic method, a liquid phase synthetic method, a solid phase synthetic method, and a vacuum synthetic method are recited. From the view point of applicability for mass production, a liquid phase synthetic method is more preferred, and in the liquid phase synthetic method, from the view point of capability of synthesizing a semiconductor phosphor microparticle having high luminous efficiency, in particular, synthetic methods such as a hot soap method, an inverse micelle method, solvothermal method, a coprecipitation method and the like is more preferably used.
The light emitting device of the present invention preferably contains two or more kinds of semiconductor phosphor microparticles from the view point of color reproducibility. On the other hand, from the view point of the luminous efficiency, the number of kinds of the semiconductor phosphor microparticles contained in the light emitting device of the present invention is preferably four or less. Therefore, the number of kinds of the semiconductor phosphor microparticles contained in the light emitting device of the present invention is particularly preferably two or more and four or less. On the other hand, from the view point of luminous efficiency and easiness of production, the semiconductor phosphor microparticle contained in the light emitting device is preferably one kind. When the number of kind of the semiconductor phosphor microparticle contained in the light emitting device is one, there arises a problem that color reproducibility is impaired because only part of wavelength range of visible light can be reproduced. However, when only one kind of semiconductor phosphor microparticle is contained in the light emitting device, reabsorption of fluorescence does not occur between phosphors, so that the luminous efficiency increases. Containing only one kind is advantageous in that production is facilitated because chromaticity adjustment by adjusting the amount of phosphor is facilitated. On the other hand, when the number of kinds of the semiconductor phosphor microparticles is four or more, there arises a problem that deterioration in luminous efficiency is significant due to absorption of fluorescence between phosphors.
A translucent member in the light emitting device of the present invention represents the one that has a function of not absorbing luminescence of the light emitting element and the semiconductor phosphor microparticle. A material not allowing permeation of moisture and oxygen is more preferred. In this case, since the influence that the semiconductor phosphor microparticle receives from moisture and oxygen can be alleviated by the translucent material, the light emitting device (and later-described image display device) using the translucent material has improved durability. As a material of the translucent member satisfying the aforementioned condition, for example, translucent resins such as silicone resin, epoxy resin, acryl resin, fluorine resin, polycarbonate resin, polyimide resin and urea resin, and translucent inorganic materials such as aluminum oxide, silicon oxide and yttria can be exemplified. As a method of identifying the material of the translucent member, X-ray photoelectron spectrometry or the like is exemplified.
As a preferred combination between the light emitting element and the semiconductor phosphor microparticle in the light emitting device of the present invention, a light emitting device having a blue luminescent light emitting element (more preferably, a blue luminescent semiconductor light emitting element) and one kind of semiconductor phosphor microparticle (for example, yellow luminescent semiconductor phosphor microparticle) is exemplified. This case is advantageous in that a light emitting device having luminous efficiency can be realized.
As a preferred combination, a light emitting device having a blue luminescent light emitting element (more preferably, a blue luminescent semiconductor light emitting element) and two kinds of semiconductor phosphor microparticles (for example, red luminescent semiconductor phosphor microparticle and green luminescent semiconductor phosphor microparticle) is also exemplified. This case is advantageous in that a light emitting device having high color reproducibility and high luminous efficiency can be realized.
Further, as a preferred combination, a light emitting device having a UV to blue-violet luminescent light emitting element (more preferably, a UV to blue-violet light emitting semiconductor light emitting element) and three kinds of semiconductor phosphor microparticles (for example, blue luminescent semiconductor phosphor microparticle, green luminescent semiconductor phosphor microparticle and red luminescent semiconductor phosphor microparticle) may be recited. This case is advantageous in that a light emitting device having high luminous efficiency can be realized because a UV to blue-violet light emitting light emitting element having high luminous efficiency can be used.
Also the light emitting device of the present invention may have a combination of a blue luminescent organic electroluminescence element and one kind of semiconductor phosphor microparticle (for example, yellow luminescent semiconductor phosphor microparticle), or a combination of a blue luminescent organic electroluminescence element and two kinds of semiconductor phosphor microparticles (for example, green luminescent semiconductor phosphor microparticle and red luminescent semiconductor phosphor microparticle). This case is advantageous in that a surface luminescent light emitting device can be readily fabricated.
Preferably, the light emitting device of the present invention has an emission spectrum containing light of blue wavelength of 420 to 480 nm, green wavelength of 500 to 550 nm, and red wavelength 580 to 650 nm. In the case of a later-described image display device, having a wavelength characteristic in conformance with a color filter is further preferred because an image display device having high color reproducibility and high luminous efficiency can be realized.
As an index for evaluating hue of the light emitting device, a color rendering property index is known. The color rendering property index refers to a quantitatively evaluated value of degree of difference in color of the emission spectrum of the light emitting device, based on the standard light defined by HS. For evaluating general hue averagely, an average color rendering property index (Ra) which is an average value of color rendering property indexes in several test colors is used. In the light emitting device of the present invention, the average color rendering property index (Ra) is preferably 70 or higher, and more preferably 75 or higher. Color rendering property index of the light emitting device may be determined by measuring the emission spectrum of the light emitting device.
Also as an index for evaluating brightness of a light emitting device, luminous efficiency is known. Luminous efficiency is a value calculated by output light quantity, with respect to input electric power, and is represented in lm/W. High luminous efficiency is preferred because bright illumination is achieved with small electric power. The light emitting device of the present invention preferably has a luminous efficiency of 15 lm/W or higher, and more preferably has a luminous efficiency of 20 lm/W or higher. As a method of measuring luminous efficiency of a light emitting device, a method of using a total luminous flux measuring apparatus or the like is exemplified.
The light emitting device of the present invention is not limited to the configurations as described above, and a conventionally known general structure may also be employed, and a similar effect is obtained by using a conventionally known light emitting element or structure.
<Image Display Device>
The present invention also provides an image display device having a feature similar to that of the light emitting device of the present invention as described above. The image display device of the present invention is characterized by having a light emitting element, and a semiconductor phosphor microparticle of a core/shell structure having a shell part that absorbs at least a part of the light emitted by the light emitting element.
The image display device of the present invention may be implemented to have a light emitting device of the present invention including a light emitting element and a semiconductor phosphor microparticle of a core/shell structure as described above, and a wavelength conversion part that converts wavelength of light emitted from the light emitting device of the present invention. This case is advantageous in that the structure is simple and production is easy. The image display device of the present invention may be implemented to have a light emitting element, and a wavelength conversion part including a wavelength conversion member containing a semiconductor phosphor microparticle of a core/shell structure as described above. This case is advantageous in that conversion loss is small and efficiency is high. The wavelength conversion part in the present invention refers to the one having a function of outputting only light of a specific wavelength upon incidence of light. As a method of realizing such a function, for example, a method of allowing certain wavelengths of input light to transmit, or a method of outputting light having a wavelength different from that of the input light is exemplified.
In the image display device of the present invention, output light emitted from the light emitting element is converted into light of each color by the semiconductor phosphor microparticle and the wavelength conversion part, and color tone of each pixel is expressed by this converted light. The image display device of the present invention is characterized in that excitation light of the light emitting element is absorbed in a shell part of the semiconductor phosphor microparticle. In the present invention, by having such a configuration, an image display device achieving both color reproducibility and screen brightness at high level can be realized.
FIG. 5 is an exploded perspective view schematically showing an image display device 101 of a first preferred example of the present invention. In image display device 101 in the example shown in FIG. 5, a plurality (16 in FIG. 5) of light emitting devices 102 (preferably, light emitting device 1 in the example shown in FIG. 1, or light emitting device 21 in the example shown in FIG. 2) are arranged as a light source on a lateral face of a transparent or translucent light conductive plate 103, and an image display part 105 made up of a plurality of wavelength conversion parts 104 is disposed adjacent to the top face of light conductive plate 103. In image display device 101 in the example shown in FIG. 5, output light 106 from light emitting device 102 is adapted to pass through light conductive plate 103, and applied to the entire surface of image display part 105 as light 107. Here, in image display device 101, light emitting device 102 exhibiting white light is used as a light source, and for display of each pixel, a color filter inside wavelength conversion part 104 is used, and for ON/OFF of each pixel, a thin-film transistor inside wavelength conversion part 104 is used. As light emitting device 102, light emitting devices 1, 21, 41 of the present invention having the configurations as shown in FIG. 1 to FIG. 3, for example, may be suitably used.
Here, FIG. 6 is an exploded perspective view showing wavelength conversion part 104 in image display device 101 in the example shown in FIG. 5 in an enlarged manner. Wavelength conversion part 104 in the example shown in FIG. 6 is made up of a lower polarizing plate 111a, a transparent conductive film 113a (having thin-film transistor 112), an oriented film 114a, a liquid crystal layer 115, an oriented film 114b, an upper thin-film electrode 113b, a color filter 116, and an upper polarizing plate 111b that are laminated in this order. Color filter 116 consists of multiple kinds of color filters (three kinds of color filters 116a, 116b, 116c in FIG. 6), and each color filter allows transmission of light of a specific wavelength range. And each section of color filter is separated into a size corresponding to transparent conductive film 113a. In wavelength conversion part 104 in the example shown in FIG. 6, ON/OFF display is enabled by controlling light transmission from lower polarizing plate 111a to upper polarizing plate 111b by thin-film transistor 112. The wavelength conversion part having such a structure is also called a liquid crystal display.
Here, the color filter in the present invention refers to the one having a function of allowing transmission of light in a specific wavelength of input light. As a raw material of the color filter having such a function, dyes and pigments are exemplified. The color filter in the present invention preferably has three or more sections. This is because three sections allow reproduction of most of naturally occurring color tones in the image display part. For the three sections, color filters respectively allowing transmission of red, green and blue light can be suitably used.
FIG. 7 is a graph showing a transmission spectrum of red color filter, a transmission spectrum of green color filter, and a transmission spectrum of blue color filter in color filters used in the image display device of the present invention, wherein the vertical axis represents transmissivity (%) and the horizontal axis represents wavelength (nm). Transmission spectrums of respective colors of the color filters used in the image display device of the present invention are not limited to those shown in the graph of FIG. 7, but conventionally known general color filters may also be used.
The light conductive plate used in the present invention, as is the example shown in FIG. 5 refers to the one having a function of alleviating the nonuniformity of in-plane brightness of light applied from the light source on the image display part. When there is nonuniformity in brightness in an in-plane direction in the light source of the image display device, brightness of the image display part becomes uneven in the in-plane direction. Therefore, by using the light conductive plate, light having uniform in-plane intensity can enter the image display part. As a light conductive plate having such a function, an acryl resin plate processed to have a surface asperity is exemplified. In such an acryl resin plate, since light is scattered by the surface asperity, light having uniform brightness in the in-plane direction can be outputted.
FIG. 8 is an exploded perspective view schematically showing an image display device 121 according to a second preferred example of the present invention. The part having a similar configuration as that of image display device 101 in the example shown in FIG. 5 is denoted by the same reference numeral, and description thereof will be omitted. Image display device 121 in the example shown in FIG. 8 has almost the same configuration as image display device 101 in the example shown in FIG. 5, but is different in that a light emitting element 122 is used as a light source, and an image display part 124 is formed from a wavelength conversion part 123. In image display device 121 in the example shown in FIG. 8, on a lateral face of transparent or translucent light conductive plate 103, a plurality (16 in FIG. 8) of light emitting elements 122 are arranged as a light source, and image display part 124 made up of a plurality of wavelength conversion parts 123 are provided adjacently to the top face of light conductive plate 103. In image display device 121 of the example shown in FIG. 8, output light 125 from light emitting element 122 is adapted to pass through light conductive plate 103, and applied on the entire surface of image display part 124 as light 126. In image display device 121 in the example shown in FIG. 8, the semiconductor light emitting element as described above may suitably be used as light emitting element 122 which is a light source, and for display of each pixel, a wavelength conversion member inside wavelength conversion part 123 is used, and for ON/OFF of each pixel, a thin-film transistor inside wavelength conversion part 123 is used.
Here, FIG. 9 is an exploded perspective view showing wavelength conversion part 123 in image display device 121 in the example shown in FIG. 8 in an enlarged manner. Wavelength conversion part 123 in the example shown in FIG. 9 has almost the same configuration as wavelength conversion part 104 in the example shown in FIG. 6, but is different in that there is a wavelength conversion member 136 in place of color filter 116. Here, the wavelength conversion member in the present invention refers to the one having a function of absorbing at least a part of input light and radiating light having a wavelength different from that of the input light. As a raw material of the wavelength conversion member having such a function, a semiconductor phosphor microparticle is exemplified. Wavelength conversion part 123 in the example shown in FIG. 9 includes a lower polarizing plate 131a, a transparent conductive film 133a (having thin-film transistor 132), an oriented film 134a, a liquid crystal layer 135, an oriented film 134b, an upper thin-film electrode 133b, a wavelength conversion member 136, and an upper polarizing plate 131b that are laminated in this order. Wavelength conversion member 136 is made up of multiple kinds of wavelength conversion members (three kinds of wavelength conversion members 136a, 136b, 136c in FIG. 9), and each wavelength conversion member emits light of a specific wavelength range. Each wavelength conversion member is divided into sections each corresponding to the size of transparent conductive film 133a. 
FIG. 10 is a section view schematically showing wavelength conversion member 136 in the example shown in FIG. 9. Wavelength conversion member 136 has such a form that a semiconductor phosphor microparticle 141 having a core/shell structure is dispersed in a translucent member 142. A part of light 143 inputted into wavelength conversion member 136 penetrates translucent member 142, and is absorbed in a shell part of semiconductor phosphor microparticle 141. Semiconductor phosphor microparticle 141 having absorbed the light emits fluorescence 145 having a wavelength different from that of the input light from a core part. Part of light 143 inputted into wavelength conversion member 136 turns into transmitted light 144. As a result, when wavelength conversion member 136 is irradiated with light 143, mixed light 146 of fluorescence 145 and transmitted light 144 is emitted.
FIG. 11 is an exploded perspective view schematically showing an image display device 151 in a third preferred example of the present invention. The part having a similar configuration as that of image display device 101 in the example shown in FIG. 5 is denoted by the same reference numeral, and description thereof will be omitted. Image display device 151 in the example shown in FIG. 11 has almost the same configuration as image display device 101 in the example shown in FIG. 5, but is different in that a light emitting device 152 (preferably, light emitting device 41 in the example shown in FIG. 3) using an organic electroluminescence element is provided as a light emitting element, and a light conductive plate is not used. That is, in image display device 151 in the example shown in FIG. 11, output light 106 from light emitting device 102 is adapted to be applied to the entire surface of image display part 105. Here in image display device 151 in the example shown in FIG. 11, light emitting device 102 exhibiting white light is used as a light source, and for display of each pixel, color filter 116 inside wavelength conversion part 104 as shown in FIG. 6 is used, and for ON/OFF of each pixel, thin-film transistor 112 inside wavelength conversion part 104 is used.
FIG. 12 is an exploded perspective view schematically showing an image display device 161 in a fourth preferred example of the present invention. The part having a similar configuration as that of image display device 121 in the example shown in FIG. 8 is denoted by the same reference numeral, and description thereof will be omitted. Image display device 161 in the example shown in FIG. 12 has almost the same configuration as image display device 121 in the example shown in FIG. 8, but is different in that an organic electroluminescence element is used as light emitting element 162 for a light source, and a light conductive plate is not used. That is, in image display device 161 in the example shown in FIG. 12, output light 163 from light emitting device 162 is adapted to be applied on the entire face of image display part 124. In image display device 161 in the example shown in FIG. 12, for display of each pixel, wavelength conversion member 136 inside wavelength conversion part 123 as shown in FIG. 9 and FIG. 10 is used, and for ON/OFF of each pixel, thin-film transistor 132 inside wavelength conversion part 123 is used.
FIG. 13 is an exploded perspective view schematically showing an image display device 171 in a fifth preferred example of the present invention. The part having a similar configuration as that of image display device 151 in the example shown in FIG. 11 is denoted by the same reference numeral, and description thereof will be omitted. Image display device 171 in the example shown in FIG. 13 has almost the same configuration as image display device 151 in the example shown in FIG. 11, but is different in that an image display part 173 is formed from a wavelength conversion part 172. Here, FIG. 14 is a perspective view showing wavelength conversion part 172 in image display part 173 in image display device 171 in the example shown in FIG. 13 in an enlarged manner. Wavelength conversion part 172 in the example shown in FIG. 14 is made up of multiple kinds of color filters 176 (three kinds of color filters 176a, 176b, 176c in the example shown in FIG. 14), and each color filter allows transmission of light of a specific wavelength range. In image display device 171 in the example shown in FIG. 13, light emitting device 152 exhibiting white light using an organic electroluminescence element as a light emitting element is used, and for display of each pixel, color filter 176 inside wavelength conversion part 172 as shown in FIG. 14 is used, and for ON/OFF of each pixel, a thin-film transistor fabricated inside light emitting device 152 is used.
FIG. 15 is an exploded perspective view schematically showing an image display device 181 in a sixth preferred example of the present invention. The part having a similar configuration as that of image display device 161 in the example shown in FIG. 12 is denoted by the same reference numeral, and description thereof will be omitted. Image display device 181 in the example shown in FIG. 15 has almost the same configuration as image display device 161 in the example shown in FIG. 12, but is different in that an image display part 183 is formed from a wavelength conversion part 18. Here, FIG. 16 is a perspective view showing wavelength conversion part 182 in image display part 183 in image display device 181 in the example shown in FIG. 15 in an enlarged manner. Wavelength conversion part 182 in the example shown in FIG. 16 is made up of multiple kinds of wavelength conversion members 186 (three kinds of wavelength conversion members 186a, 186b, 186c in the example shown in FIG. 16), and each wavelength conversion member emits light of a specific wavelength range. Here, in image display device 181 in the example shown in FIG. 15, an organic electroluminescence element is used as light emitting element 162 which is a light source, and for display of each pixel, wavelength conversion member 186 inside wavelength conversion part 182 is used, and for ON/OFF of each pixel, a thin-film transistor fabricated inside light emitting element 162 is used.
As one of performances of the image display device of the present invention, color reproducibility is recited. Color reproducibility represents the size of the color area where the image display device is able to display, and is evaluated by using an NTSC ratio. In the image display device of the present invention, an NTSC ratio is preferably 100% or higher. The NTSC ratio is calculated by an area ratio of an triangle obtained by connecting chromaticity coordinates of each color of red, green and blue in chromaticity coordinates (u′, v′) in a CIE1976 chromaticity chart, with respect to the area of the triangle obtained by connecting chromaticity coordinates (u′, v′) in CIE1976 chromaticity chart of each color (red (0.498, 0.519), green (0.076, 0.576), blue (0.152, 0.196)) of red, green and blue defined by NTSC (National Television System Committee).
As one of performances of the image display device of the present invention, screen brightness is recited. Brightness represents intensity of light emitted from the image display device. Brightness in the present invention is calculated as screen brightness when RGB pixels are fully opened and displayed in white.
In the image display device of the present invention, from the view point of increasing the NTSC ratio, standard deviation of particle diameter distribution of a core part of the semiconductor phosphor microparticle is preferably 20% or less, and more preferably 15% or less of mean particle diameter of a core part of the semiconductor phosphor microparticle.
Also in the image display device of the present invention, a half-value width of an emission spectrum of semiconductor phosphor microparticle is preferably narrow. This is because a narrow half-value width of an emission spectrum realizes an image display device having high color reproducibility. In this case, as a concrete example, the half-value width of the emission spectrum is preferably 80 nm or less, more preferably 60 nm or less, and particularly preferably 40 nm or less.
As for the image display device of the present invention, conventionally known general structures may also be employed without limited to the configurations as described above.
In the following, the present invention will be described in more detail by way of Examples and Comparative examples, however, the present invention will not be limited to these examples.
<Synthesis of Semiconductor Phosphor Microparticle Core Part>
In the following, a synthetic method of a core part of a semiconductor phosphor microparticle wherein a material of the core part is InP, GaInP, InN, GaInN, CdSe, or ZnCdSe will be described. In the following synthetic example, for measurement of a crystal structure of a semiconductor phosphor microparticle, powder X-ray diffraction measuring apparatus Ultima IV (available from Rigaku Corporation) was used, and for measurement of particle diameter and particle diameter distribution of a semiconductor phosphor microparticle, a transmission electron microscope JEM-2100 (available from JEOL Ltd.) was used.
Synthetic Example A1
Synthesis of InP Core Part
In Synthetic example A1, a core part formed of InP microcrystal was synthesized.
First, in a glove box in a dry nitrogen atmosphere, 200 mL of trioctylphosphine and 17.3 g of trioctylphosphine oxide were weighed, and mixed, and stirred for 10 minutes to obtain Mixed solvent A.
Then Mixed solvent A in the glove box was added and mixed with 2.2 g (10.0 mmol) of indium trichloride which is a group III metal element material, and 2.5 g (10.0 mmol) of tris(trimethylsilyl)phosphine which is a group V element material of semiconductor microparticle, and then stirred for 10 minutes at 20° C., to obtain Material solution B.
Next, Material solution B was stirred under heating for 72 hours in a pressure container of nitrogen atmosphere, to allow synthesis of the materials contained in Material solution B, to obtain Synthetic solution C. Synthetic solution C after end of synthetic reaction was cooled to room temperature by allowing it to dissipate the heat naturally, and Synthetic solution C was collected in a dry nitrogen atmosphere.
This Synthetic solution C was subjected to a classification step in which an operation of adding 200 mL of dehydrated methanol which is a poor solvent to make a semiconductor phosphor microparticle precipitate, an operation of making a semiconductor phosphor microparticle precipitate by centrifugation at 4000 rpm for 10 minutes, and an operation of dissolving the semiconductor phosphor microparticle by adding dehydrated toluene are respectively repeated for 10 times, to obtain Dehydrated toluene solution D containing a semiconductor phosphor microparticle having a specific particle diameter. And by evaporation of the dehydrated toluene solvent from Dehydrated toluene solution D, Solid powder E was collected.
Diffraction peak of Solid powder E was observed by powder X-ray diffraction, and it was found that Solid powder E was InP crystal because a diffraction peak was observed in the position of InP. Further, Solid powder E was directly observed under a transmission electron microscope, and particle diameters of 20 particles were measured, and mean particle diameter was calculated from the average value of the values of respective particle diameters, and thus mean particle diameter of InP crystal was determined.
Synthetic Example A2
Synthesis of InP Core Part
In Synthetic example A1, a core part formed of InP microcrystal of Synthetic example A2 was synthesized in a production method similar to that of Synthetic example A1 except that a classification step was changed. That is, while the steps of precipitation and redissolution were respectively repeated 10 times in Synthetic example A1, the steps of precipitation and redissolution were respectively repeated 5 times in Synthetic example A2. A core part formed of InP microcrystal of Synthetic example A2 was synthesized in a production method similar to that of Synthetic example A1 except for the classification step.
Solid powder E was measured by XRD, and it was found that Solid powder E was InP crystal because a diffraction peak was observed in the position of InP. Further, by directly observing Solid powder E using TEM, mean particle diameter and particle diameter distribution of InP were determined. Particle diameter distribution of an InP core part obtained in Synthetic example A2 was larger than particle diameter distribution of an InP core part of Synthetic example A1.
Synthetic example A3
Synthesis of InP Core Part
In Synthetic example A1, a core part formed of InP microcrystal of Synthetic example A3 was synthesized in a production method similar to that of Synthetic example A1 except that a classification step was changed. That is, while the steps of precipitation and redissolution were respectively repeated 10 times in Synthetic example A1, the steps of precipitation and redissolution were respectively repeated twice in Synthetic example A3. A core part formed of InP microcrystal of Synthetic example A3 was synthesized in a production method similar to that of Synthetic example A1 except for the classification step.
Solid powder E was measured by XRD, and it was found that Solid powder E was InP crystal because a diffraction peak was observed in the position of InP. Further, by directly observing Solid powder E using TEM, mean particle diameter and particle diameter distribution of InP can be determined. Particle diameter distribution of an InP core part obtained in Synthetic example A3 was larger than particle diameter distribution of an InP core part of Synthetic examples A1, A2.
Synthetic Example A4
Synthesis of In0.5Ga0.5P Core Part
A core part formed of InGaP microcrystal of Synthetic example A4 was synthesized in a production method similar to that of Synthetic example A1 except that part of the group III metal element material added to Mixed solution A in Synthetic example A1 was changed to gallium trichloride. That is, while 2.2 g (10.0 mmol) of indium trichloride was used as a group III metal element material of a core part in Synthetic example A1, 1.1 g (5.0 mmol) of indium trichloride and 0.88 g (5.0 mmol) of gallium trichloride were used as the group III metal element material in Synthetic example A4. A core part formed of InGaP microcrystal of Synthetic example A4 was synthesized in a production method similar to that of Synthetic example A1 except for the difference in group III metal element material.
Solid powder E was measured by XRD, and it was found that Solid powder E was In0.5Ga0.5P crystal because a diffraction peak was observed in the position of In0.5Ga0.5P. Further, by directly observing Solid powder E using TEM, mean particle diameter and particle diameter distribution of In0.5Ga0.5P crystal were determined.
Synthetic Example A5
Synthesis of In0.3Ga0.7P Core Part
A core part formed of InGaP microcrystal of Synthetic example A5 was synthesized in a production method similar to that of Synthetic example A4 except that a ratio of the group III metal element material added to Mixed solution A in Synthetic example A4 was changed. That is, while 1.1 g (5.0 mmol) of indium trichloride and 0.88 g (5.0 mmol) of gallium trichloride were used as the group III metal element material of a core part in Synthetic example A4, 1.5 g (7.0 mmol) of indium trichloride and 0.53 g (3.0 mmol) of gallium trichloride were used as the group III metal element material in Synthetic example A5. A core part formed of InGaP microcrystal of Synthetic example A5 was synthesized in a production method similar to that of Synthetic example A4 except for the difference in group III metal element material.
Solid powder E was measured by XRD, and it was found that Solid powder E was In0.3Ga0.7P crystal because a diffraction peak was observed in the position of In0.3Ga0.7P. Further, by directly observing Solid powder E using TEM, mean particle diameter and particle diameter distribution of In0.3Ga0.7P crystal were determined.
Synthetic Example A6
Synthesis of InN Core Part
A core part formed of InN microcrystal of Synthetic example A6 was synthesized in a production method similar to that of Synthetic example A1 except that a group V element material added to Mixed solution A in Synthetic example A1 was changed to bis(trimethylsilyl)amine. That is, while tris(trimethylsilyl)phosphine was used as the group V element material in Synthetic example A1, 1.6 g (10.0 mmol) of bis(trimethylsilyl)amine was used as a group V element material in Synthetic example A6. Solid powder E of semiconductor phosphor microparticle was obtained in a production method similar to that of Synthetic example A1 except for the difference in condition of the group V element material.
Solid powder E was measured by XRD, and it was found that Solid powder E was InN crystal because a diffraction peak was observed in the position of InN. Further, by directly observing Solid powder E using TEM, mean particle diameter (diameter) and particle diameter distribution of InN were determined.
Synthetic Example A7
Synthesis of InN Core Part
In Synthetic example A6, a core part formed of InN microcrystal of Synthetic example A7 was synthesized in a production method similar to that of Synthetic example A6 except that a classification step was changed. That is, while the steps of precipitation and redissolution were respectively repeated 10 times in Synthetic example A6, the steps of precipitation and redissolution were respectively repeated 5 times in Synthetic example A7. A core part formed of InN microcrystal of Synthetic example A7 was synthesized in a production method similar to that of Synthetic example A6 except for the classification step.
Solid powder E was measured by XRD, and it was found that Solid powder E was InN crystal because a diffraction peak was observed in the position of InN. Further, by directly observing Solid powder E using TEM, mean particle diameter and particle diameter distribution of InN were determined. Particle diameter distribution of an InN core part obtained in Synthetic example A7 was larger than particle diameter distribution of an InN core part of Synthetic example A6.
Synthetic Example A8
Synthesis of InN Core Part
In Synthetic example A6, a core part formed of InN microcrystal of Synthetic example A8 was synthesized in a production method similar to that of Synthetic example A6 except that a classification step was changed. That is, while the steps of precipitation and redissolution were respectively repeated 10 times in Synthetic example A6, the steps of precipitation and redissolution were respectively repeated twice in Synthetic example A8. A core part formed of InN microcrystal of Synthetic example A8 was synthesized in a production method similar to that of Synthetic example A6 except for the classification step.
Solid powder E was measured by XRD, and it was found that Solid powder E was InN crystal because a diffraction peak was observed in the position of InN, Further, by directly observing Solid powder E using TEM, mean particle diameter and particle diameter distribution of InN were determined. Particle diameter distribution of an InN core part obtained in Synthetic example A8 was larger than particle diameter distribution of an InN core part of Synthetic example A6, A7.
Synthetic Example A9
Synthesis of In0.6Ga0.4N Core Part
A core part formed of InGaN microcrystal of Synthetic example A9 was synthesized in a production method similar to that of Synthetic example A6 except that part of the group III metal element material added to Mixed solution A in Synthetic example A6 was changed to gallium trichloride. That is, while 2.2 g (10.0 mmol) of indium trichloride was used as the group III metal element material in Synthetic example A6, 1.3 g (6.0 mmol) of indium trichloride and 0.7 g (4.0 mmol) of gallium trichloride were used as the group III metal element material in Synthetic example A9. A core part formed of InGaN microcrystal of Synthetic example A9 was synthesized in a production method similar to that of Synthetic example A6 except that the group III metal element material differs.
Solid powder E was measured by XRD, and it was found that Solid powder E was In0.6Ga0.4N crystal because a diffraction peak was observed in the position of In0.6Ga0.4N. Further, by directly observing Solid powder E using TEM, mean particle diameter and particle diameter distribution of In0.6Ga0.4N were determined.
Synthetic Example A10
Synthesis of In0.8Ga0.2N Core Part
A core part formed of InGaN microcrystal of Synthetic example A10 was synthesized in a production method similar to that of Synthetic example A9 except that a ratio of the group III metal element material added to Mixed solution A in Synthetic example A9 was changed. That is, while 1.3 g (6.0 mmol) of indium trichloride and 0.7 g (4.0 mmol) of gallium trichloride were used as the group III metal element material in Synthetic example A9, 1.7 g (8.0 mmol) of indium trichloride and 0.35 g (2.0 mmol) of gallium trichloride were used as the group III metal element material in Synthetic example A9. A core part formed of InGaN microcrystal of Synthetic example A10 was synthesized in a production method similar to that of Synthetic example A9 except for the difference in group III metal element material.
Solid powder E was measured by XRD, and it was found that Solid powder E was In0.8Ga0.2N crystal because a diffraction peak was observed in the position of In0.8Ga0.2N. Further, by directly observing Solid powder E using TEM, mean particle diameter and particle diameter distribution of In0.8Ga0.2N can be determined.
Synthetic Example A11
Synthesis of CdSe Core Part
A core part formed of CdSe microcrystal of Synthetic example A11 was synthesized in a production method similar to that of Synthetic example A1 except that the group III metal element material added to Mixed solution A in Synthetic example A1 was changed to a group II metal element material, and the group V element material was changed to a group VI element material. That is, in Synthetic example A11, as a material, 1.4 g (10.0 mmol) of dimethylcadmium which is a group II metal element material and 4.5 g (10.0 mmol) of trioctyl phosphine sulfide which is a group VI element material were used. Solid powder E of semiconductor phosphor microparticle was obtained in a production method similar to that of Synthetic example A1 except for the difference in material.
Solid powder E was measured by XRD, and it was found that Solid powder E was CdSe crystal because a diffraction peak was observed in the position of CdSe. Further, by directly observing Solid powder E using TEM, mean particle diameter and particle diameter distribution of CdSe were determined.
Synthetic Example A12
Synthesis of Zn0.1Cd0.9Se Core Part
A core part formed of ZnCdSe microcrystal of Synthetic example A12 was synthesized in a production method similar to that of Synthetic example A11 except that the group II metal element material added to Mixed solution A was changed to two kinds of group H metal element materials. That is, in Synthetic example A12, 0.14 g (1.0 mmol) of dimethylcadmium and 1.1 g (9.0 mmol) of zinc diethyl were used as the group II metal element material. Solid powder E of semiconductor phosphor microparticle was obtained in a production method similar to that of Synthetic example A5 except for the difference in group II metal element material.
Solid powder E was measured by XRD, and it was found that Solid powder E was Zn0.1Cd0.9Se crystal because a diffraction peak was observed in the position of Zn0.1Cd0.9Se. Further, by directly observing Solid powder E using TEM, mean particle diameter and particle diameter distribution of Zn0.1Cd0.9Se can be determined.
<Synthesis of Semiconductor Phosphor Microparticle Shell Part>
In the following, a synthetic method of a semiconductor phosphor microparticle having a core/shell structure wherein the material of the shell part is ZnSe, SiC, GaInN, ZnSTe, GaP, SiO2, ZnS, or GaN will be described.
Synthetic Example B1
Synthesis of ZnSe Shell Part
In Synthetic example B1, a semiconductor phosphor microparticle having a core/shell structure having a ZnSe shell part was synthesized.
First, in a glove box in a dry nitrogen atmosphere, semiconductor phosphor microparticle core part, 200 mL of trioctylphosphine and 17.3 g of trioctylphosphine oxide were weighed, and mixed, and stirred for 10 minutes to obtain Mixed solvent A.
Then, in the condition that Mixed solvent A was heated to a shell growth temperature under stirring in a flask, 1.2 g (10.0 mmol) of zinc diethyl which is a group II metal element material of a semiconductor microparticle shell part, and 4.5 g (10.0 mmol) of trioctylphosphine selenide which is a group VI element material of a semiconductor microparticle shell part were separately added dropwise gradually over 8 hours, to obtain Synthetic solution C.
This Synthetic solution C was subjected to a classification step in which an operation of adding 200 mL of dehydrated methanol which is a poor solvent to make a semiconductor phosphor microparticle precipitate, an operation of making a semiconductor phosphor microparticle precipitate by centrifugation at 4000 rpm for 10 minutes, and an operation of dissolving the semiconductor phosphor microparticle by adding dehydrated toluene are respectively repeated for 10 times, to obtain Dehydrated toluene solution D containing a semiconductor phosphor microparticle having a specific particle diameter. And by evaporation of the dehydrated toluene solvent from Dehydrated toluene solution D, Solid powder E was collected. This Solid powder E was directly observed under a transmission electron microscope, and a semiconductor phosphor microparticle having a core/shell structure in which the surface of the core part is covered with a ZnSe shell was observed.
Synthetic Example B2
Synthesis Of SiC Shell Part
A semiconductor phosphor microparticle having a core/shell structure having a SiC shell part of Synthetic example B2 was synthesized in a production method similar to that of Synthetic example B1 except that the material added to Mixed solution A in Synthetic example B1 was changed to two kinds of group IV metal element materials. That is, in Synthetic example B2, 5.0 g of polycarbosilane was used as the group IV element material. Solid powder E of semiconductor phosphor microparticle was obtained in a production method similar to that of Synthetic example B1 except for the difference in group II metal element material. By direct observation of this Solid powder E under a transmission electron microscope, a semiconductor phosphor microparticle having a core/shell structure in which the surface of the core part is covered with SiC shell part was observed.
Synthetic Example B3
Synthesis of In0.25Ga0.75N Shell Part
A semiconductor phosphor microparticle having a core/shell structure having an InGaN shell part of Synthetic example B3 was synthesized in a production method similar to that of Synthetic example B1 except that the group II metal element material added to Mixed solution A in Synthetic example B1 was changed to two kinds of group III metal element material and the group VI element material was changed to a group V element material. That is, in Synthetic example B3, 0.54 g (2.5 mmol) of indium trichloride and 1.3 g (7.5 mmol) of gallium trichloride were used as the group III metal element material, 1.6 g (10.0 mmol) of bis(trimethylsilyl)amine was used as the group V element material. Solid powder E of semiconductor phosphor microparticle was obtained in a production method similar to that of Synthetic example B1 except for the differences in group III metal element material and group V element material. By direct observation of this Solid powder E under a transmission electron microscope, a semiconductor phosphor microparticle having a core/shell structure in which the surface of the core part is covered with an In0.25Ga0.75N shell part was observed.
Synthetic Example B4
Synthesis of ZnS0.35Te0.65 Shell Part
A semiconductor phosphor microparticle having a core/shell structure having a ZnSTe shell part of Synthetic example B4 was synthesized in a production method similar to that of Synthetic example B1 except that the group II metal element material added to Mixed solution A in Synthetic example B1 was changed to group V element material. That is, in Synthetic example B4, 1.2 g (10.0 mmol) of zinc diethyl was used as the group II metal element material, 1.4 g (3.5 mmol) of trioctylphosphine sulfide and 3.2 g (6.5 mmol) of trioctylphosphineterenide were used as the group VI element material. Solid powder E of semiconductor phosphor microparticle was obtained in a production method similar to that of Synthetic example B1 except for the difference in group II metal element material and group VI element material. By direct observation of this Solid powder E under a transmission electron microscope, a semiconductor phosphor microparticle having a core/shell structure in which the surface of the core part is covered with a ZnS0.35Te0.65 shell part was observed.
Synthetic Example B5
Synthesis of GaP Shell Part
A semiconductor phosphor microparticle having a core/shell structure having a GaP shell part of Synthetic example B5 was synthesized in a production method similar to that of Synthetic example B1 except that the group II metal element material added to Mixed solution A in Synthetic example B1 was changed to a group III metal element material, and the group VI element material was changed to a group V element material. That is, in Synthetic example B5, 1.8 g (10.0 mmol) of gallium trichloride was used as the group III metal element material, and 2.5 g (10.0 mmol) of tris(trimethylsilyl)phosphine was used as the group V element material. Solid powder E of semiconductor phosphor microparticle was obtained in a production method similar to that of Synthetic example B1 except for the differences in group III metal element material and group V element material. By direct observation of this Solid powder E under a transmission electron microscope, a semiconductor phosphor microparticle having a core/shell structure in which the surface of the core part is covered with a GaP shell part was observed.
Synthetic Example B6
Synthesis of SiO2 Shell Part
A semiconductor phosphor microparticle having a core/shell structure having a SiO2 shell part of Synthetic example B6 was synthesized in a production method similar to that of Synthetic example B1 except that the material added to Mixed solution A in Synthetic example B1 was changed. That is, in Synthetic example B6, 2.2 g (10.0 mmol) of aminopropyltrimethoxysilane and 0.92 g (10.0 mmol) of thioglycolic acid were used. Solid powder E of semiconductor phosphor microparticle was obtained in a production method similar to that of Synthetic example B1 except for the difference in material. By direct observation of this Solid powder E under a transmission electron microscope, a semiconductor phosphor microparticle having a core/shell structure in which the surface of the core part is covered with a SiO shell part was observed.
Synthetic Example B7
Synthesis of ZnS Shell Part
A semiconductor phosphor microparticle having a core/shell structure having a ZnS shell part of Synthetic example B7 was synthesized in a production method similar to that of Synthetic example B1 except that the group W element material added to Mixed solution A in Synthetic example B1 was changed. That is, in Synthetic example B7, 4.0 g (10.0 mmol) of trioctylphosphine sulfide was used as the group VI element material. Solid powder E of semiconductor phosphor microparticle was obtained in a production method similar to that of Synthetic example B1 except for the difference in group VI element material. By direct observation of this Solid powder E under a transmission electron microscope, a semiconductor phosphor microparticle having a core/shell structure in which the surface of the core part is covered with a ZnS shell part was observed.
Synthetic Example B8
Synthesis of GaN Shell Part
A semiconductor phosphor microparticle having a core/shell structure having a GaN shell part of Synthetic example B8 was synthesized in a production method similar to that of Synthetic example B1 except that the group II metal element material added to Mixed solution A in Synthetic example B1 was changed to a group III metal element material and the group VI element material was changed to a group V element material. That is, in Synthetic example B8, 1.75 g (10.0 mmol) of gallium trichloride was used as the group III metal element material and, 1.6 g (10.0 mmol) of bis(trimethylsilyl)amine was used as the group V element material. Solid powder E of semiconductor phosphor microparticle was obtained in a production method similar to that of Synthetic example B1 except for the differences in group III metal element material and group V element material. By direct observation of this Solid powder E under a transmission electron microscope, a semiconductor phosphor microparticle having a core/shell structure in which the surface of the core part is covered with a GaN shell part was observed.
<Production of Semiconductor Phosphor Microparticle>
In the following, a method of producing a semiconductor phosphor microparticle having a core/shell structure wherein a material of a core part is selected from the group consisting of InP, InGaP, InN, InGaN, CdSe, and ZnCdSe, and a material of a shell part is selected from ZnSe, SiC, InGaN, ZnSTe, GaP, SiO2, ZnS, and GaN will be described. In the following production example, a fluorescence spectrophotometer FluoroMax-4 (available from JOBIN YVON) was used for measurement of luminous characteristics of a semiconductor phosphor microparticle, and a spectrophotometer U-4100 (available from Hitachi High-Technologies Corporation) was used for measurement of an absorption spectrum of a semiconductor phosphor microparticle.
Production Example 1r
Production of InP/ZnSe Red Luminescent Semiconductor Phosphor Microparticle
In Production example 1r, an InP/ZnSe semiconductor phosphor microparticle showing red luminescence was produced.
First, an InP core part was synthesized using the method shown in Synthetic example A1. By means of a transmission electron microscope, it was proved that mean particle diameter of the InP core part was 3.8 nm, and particle diameter distribution was 14.8%. Then using the method shown in Synthetic example B1, a ZnSe shell part was synthesized on the surface of the InP core part. By means of a transmission electron microscope, it was determined that film thickness of the shell part was 0.8 nm. In this manner, an InP/ZnSe semiconductor phosphor microparticle was produced. The produced InP/ZnSe semiconductor phosphor microparticle was proved to emit red light upon irradiation by a UV lamp.
The obtained InP/ZnSe semiconductor phosphor microparticle was proved to have a emission peak wavelength of 629.2 nm and an emission half-value width of 39.3 nm by conducting photoluminescence measurement. Also by conducting an absorption spectrum measurement, it was proved that the absorption wavelength was 459.2 nm. Also it was proved that the luminous efficiency was 51.8%.
Production Examples 2r to 22r
Productions of Various Red Luminescent Semiconductor Phosphor Microparticles
Using a method similar to that of Production example 1r, various red luminescent semiconductor phosphor microparticles of Production examples 2r to 22r were produced using Synthetic examples A1 to A12, and Synthetic examples B1 to B10, as shown in Table 1. As shown in Table 1, semiconductor phosphor microparticles of Comparative production examples 1r to 6r were also produced. Luminescence and absorption characteristics of these semiconductor phosphor microparticle are shown in Table 2.









TABLE 1







Production example

Structure of semiconductor














Red phosphor
Yellow phosphor
Green phosphor
Blue phosphor
Core part
Shell part 1
Shell part 2
phosphor microparticle





Production
Production
Production
Production
Synthetic
Synthetic
—
InP/ZnSe


example 1r
example 1y
example 1g
example 1b
example A1
example B1


Production
Production
Production
Production
Synthetic
Synthetic
—
InP/ZnSe


example 2r
example 2y
example 2g
example 2b
example A2
example B1


Production
Production
Production
Production
Synthetic
Synthetic
—
InP/ZnSe


example 3r
example 3y
example 3g
example 3b
example A3
example B1


Production
Production
Production
Production
Synthetic
Synthetic
Synthetic
InP/ZnSe/SiO2


example 4r
example 4y
example 4g
example 4b
example A1
example B1
example B6


Production
Production
Production
Production
Synthetic
Synthetic
—
Ga0.5In0.5P/ZnSe


example 5r
example 5y
example 5g
example 5b
example A4
example B1


Production
Production
Production
Production
Synthetic
Synthetic
—
Ga0.3In0.7P/ZnSe


example 6r
example 6y
example 6g
example 6b
example A5
example B1


Production
Production
Production
Production
Synthetic
Synthetic
—
InN/ZnSe


example 7r
example 7y
example 7g
example 7b
example A6
example B1


Production
Production
Production
Production
Synthetic
Synthetic
—
InN/ZnSe


example 8r
example 8y
example 8g
example 8b
example A7
example B1


Production
Production
Production
Production
Synthetic
Synthetic
—
InN/ZnSe


example 9r
example 9y
example 9g
example 9b
example A8
example B1


Production
Production
Production
Production
Synthetic
Synthetic
Synthetic
InN/ZnSe/SiO2


example 10r
example 10y
example 10g
example 10b
example A6
example B1
example B6


Production
Production
Production
Production
Synthetic
Synthetic
—
CdSe/ZnSe


example 11r
example 11y
example 11g
example 10b
example A11
example B1


Production
Production
Production
Production
Synthetic
Synthetic
—
Zn0.1Cd0.9Se/ZnSe


example 12r
example 12y
example 12g
example 12b
example A12
example B1


Production
Production
Production
Production
Synthetic
Synthetic
—
InP/Ga0.75In0.25N


example 13r
example 13y
example 13g
example 13b
example A1
example B3


Production
Production
Production
Production
Synthetic
Synthetic
—
InN/Ga0.75In0.25N


example 14r
example 14y
example 14g
example 14b
example A6
example B3


Production
Production
Production
Production
Synthetic
Synthetic
—
Ga0.4In0.6N/Ga0.75In0.25N


example 15r
example 15y
example 15g
example 15b
example A9
example B3


Production
Production
Production
Production
Synthetic
Synthetic
—
Ga0.2In0.8N/Ga0.75In0.25N


example 16r
example 16y
example 16g
example 16b
example A10
example B3


Production
Production
Production
Production
Synthetic
Synthetic
—
InP/ZnS0.35Te0.65


example 17r
example 17y
example 17g
example 17b
example A1
example B4


Production
Production
Production
Production
Synthetic
Synthetic
—
InN/ZnS0.35Te0.65


example 18r
example 18y
example 18g
example 18b
example A6
example B4


Production
Production
Production
Production
Synthetic
Synthetic
—
InP/SiC


example 19r
example 19y
example 19g
example 19b
example A1
example B2


Production
Production
Production
Production
Synthetic
Synthetic
—
InN/SiC


example 20r
example 20y
example 20g
example 20b
example A6
example B2


Production
Production
—
—
Synthetic
Synthetic
—
InP/GaP


example 21r
example 21y


example A1
example B5


Production
Production
—
—
Synthetic
Synthetic
—
InN/GaP


example 22r
example 22y


example A6
example B5


Comparative
Comparative
Comparative
Comparative
Synthetic
Synthetic
—
InP/ZnS


production
production
production
production
example A1
example B7


example 1r
example 1y
example 1g
example 1b


Comparative
Comparative
Comparative
Comparative
Synthetic
Synthetic
—
Ga0.5In0.5P/ZnS


production
production
production
production
example A4
example B7


example 2r
example 2y
example 2g
example 2b


Comparative
Comparative
Comparative
Comparative
Synthetic
Synthetic
—
CdSe/ZnS


production
production
production
production
example A11
example B7


example 3r
example 3y
example 3g
example 3b


Comparative
Comparative
Comparative
Comparative
Synthetic
Synthetic
—
Zn0.1Cd0.9Se/ZnS


production
production
production
production
example A12
example B7


example 4r
example 4y
example 4g
example 4b


Comparative
Comparative
Comparative
Comparative
Synthetic
Synthetic
—
InN/GaN


production
production
production
production
example A6
example B8


example 5r
example 5y
example 5g
example 5b


Comparative
Comparative
Comparative
Comparative
Synthetic
Synthetic
—
Ga0.4In0.6N/GaN


production
production
production
production
example A9
example B8


example 6r
example 6y
example 6g
example 6b


























TABLE 2














Distribution






Emission
Emission

Shell
Core
of core
Core part
Shell part



















peak
half-value

absorption
particle
particle
bandgap
band gap
Chromaticity


Production
Luminescent
wavelength
width
Luminous
wavelength
diameter
diameter
energy
energy
chart


















example
color
[nm]
[nm]
efficiency
[nm]
[nm]
[%]
[eV]
[eV]
u′
v′





















Production
Red
629.2
39.3
0.518
459.2
3.8
14.6
1.97
2.70
0.5071
0.5239


example 1r


Production
Red
627.2
60.4
0.506
457.5
3.8
27.3
1.98
2.70
0.4476
0.5328


example 2r


Production
Red
627.5
81.4
0.495
459.4
3.8
48.5
1.98
2.70
0.3976
0.5401


example 3r


Production
Red
628.3
38.1
0.515
458.2
3.8
15.2
1.97
2.70
0.5063
0.5240


example 4r


Production
Red
626.3
38.4
0.375
458.4
6.1
13.9
1.98
2.70
0.4979
0.5253


example 5r


Production
Red
634.6
41.6
0.392
458.7
5.4
16.3
1.95
2.70
0.5209
0.5218


example 6r


Production
Red
630.5
39.0
0.177
459.2
2.0
13.9
1.97
2.70
0.5125
0.5231


example 7r


Production
Red
633.8
58.6
0.210
458.4
2.0
28.4
1.96
2.70
0.4755
0.5286


example 8r


Production
Red
627.1
80.6
0.219
460.1
2.0
42.6
1.98
2.70
0.3980
0.5400


example 9r


Production
Red
632.1
40.1
0.195
458.8
2.0
16.1
1.96
2.70
0.5156
0.5226


example 10r


Production
Red
629.8
38.8
0.793
458.8
5.2
16.0
1.97
2.70
0.5104
0.5234


example 11r


Production
Red
628.6
40.3
0.609
457.9
6.3
17.6
1.97
2.70
0.5026
0.5246


example 12r


Production
Red
629.1
37.6
0.520
457.1
3.8
15.4
1.97
2.72
0.5106
0.5234


example 13r


Production
Red
630.3
41.5
0.201
456.0
2.0
16.1
1.97
2.72
0.5060
0.5240


example 14r


Production
Red
630.8
39.0
0.085
455.7
6.0
14.0
1.97
2.72
0.5135
0.5229


example 15r


Production
Red
633.2
41.9
0.119
457.5
3.4
16.7
1.96
2.72
0.5153
0.5227


example 16r


Production
Red
633.6
39.1
0.500
458.1
3.8
15.7
1.96
2.72
0.5229
0.5215


example 17r


Production
Red
631.5
38.1
0.191
455.7
2.0
13.9
1.96
2.72
0.5177
0.5223


example 18r


Production
Red
634.6
42.4
0.483
434.2
3.8
16.2
1.95
2.86
0.5188
0.5221


example 19r


Production
Red
628.6
40.5
0.209
433.9
2.0
17.9
1.97
2.86
0.5020
0.5246


example 20r


Production
Red
630.2
39.1
0.489
547.7
3.8
14.7
1.97
2.27
0.5110
0.5233


example 21r


Production
Red
633.4
37.6
0.181
546.4
2.0
14.9
1.96
2.27
0.5255
0.5211


example 22r


Comparative
Red
630.7
38.2
0.497
347.9
3.8
15.0
1.97
3.56
0.5148
0.5227


production


example 1r


Comparative
Red
633.0
40.0
0.402
349.3
6.1
15.6
1.96
3.56
0.5190
0.5221


production


example 2r


Comparative
Red
626.0
38.2
0.808
347.3
5.2
16.2
1.98
3.56
0.4970
0.5254


production


example 3r


Comparative
Red
630.1
40.9
0.583
349.3
6.3
16.6
1.97
3.56
0.5069
0.5239


production


example 4r


Comparative
Red
634.6
40.5
0.192
366.5
2.0
17.4
1.95
3.39
0.5232
0.5215


production


example 5r


Comparative
Red
629.8
38.8
0.091
364.5
6.0
16.8
1.97
3.39
0.5103
0.5234


production


example 6r









Production Examples 1y to 22y
Productions of Various Yellow Luminescent Semiconductor Phosphor Microparticles
Using a method similar to that of Production example 1r, various yellow luminescent semiconductor phosphor microparticles of Production examples 1y to 22y were produced using Synthetic examples A1 to A12 and Synthetic examples B1 to B10, as shown in Table 1. As shown in Table 1, semiconductor phosphor microparticles of Comparative production examples 1y to 6y were also produced. Luminescence and absorption characteristics of these semiconductor phosphor microparticle are shown in Table 3.

















TABLE 3














Distribution






Emission
Emission

Shell
Core
of core
Core part
Shell part



















peak
half-value

absorption
particle
particle
bandgap
band gap
Chromaticity


Production
Luminescent
wavelength
width
Luminous
wavelength
diameter
diameter
energy
energy
chart


















example
color
[nm]
[nm]
efficiency
[nm]
[nm]
[%]
[eV]
[eV]
u′
v′





















Production
Yellow
582.1
40.1
0.522
458.9
3.2
14.6
2.13
2.70
0.2673
0.5596


example 1y


Production
Yellow
584.8
57.7
0.506
457.1
3.2
29.4
2.12
2.70
0.2707
0.5588


example 2y


Production
Yellow
581.9
78.6
0.512
460.4
3.2
41.8
2.13
2.70
0.2474
0.5609


example 3y


Production
Yellow
576.2
40.9
0.512
459.5
3.2
15.3
2.15
2.70
0.2366
0.5641


example 4y


Production
Yellow
582.9
42.1
0.382
460.7
5.5
16.9
2.13
2.70
0.2705
0.5591


example 5y


Production
Yellow
583.3
37.8
0.411
457.8
4.3
13.3
2.13
2.70
0.2748
0.5585


example 6y


Production
Yellow
578.6
42.2
0.188
460.8
1.7
16.8
2.14
2.70
0.2485
0.5623


example 7y


Production
Yellow
583.3
63.1
0.204
460.5
1.7
32.2
2.13
2.70
0.2608
0.5601


example 8y


Production
Yellow
582.1
82.0
0.218
459.8
1.7
47.2
2.13
2.70
0.2463
0.5607


example 9y


Production
Yellow
583.3
39.5
0.194
458.3
1.7
15.8
2.13
2.70
0.2742
0.5586


example 10y


Production
Yellow
583.0
40.8
0.800
459.3
5.4
17.8
2.13
2.70
0.2721
0.5589


example 11y


Production
Yellow
575.8
37.7
0.592
460.3
6.1
15.9
2.15
2.70
0.2350
0.5644


example 12y


Production
Yellow
582.1
37.9
0.488
457.6
6.1
15.3
2.13
2.72
0.2683
0.5595


example 13y


Production
Yellow
584.3
38.1
0.184
457.6
1.7
15.1
2.12
2.72
0.2802
0.5577


example 14y


Production
Yellow
584.0
42.1
0.088
456.5
5.2
16.3
2.12
2.72
0.2765
0.5582


example 15y


Production
Yellow
584.4
40.6
0.082
457.5
3.0
17.7
2.12
2.72
0.2797
0.5578


example 16y


Production
Yellow
579.1
39.8
0.501
455.3
3.2
15.4
2.14
2.72
0.2519
0.5619


example 17y


Production
Yellow
581.6
38.1
0.217
456.0
1.7
16.4
2.13
2.72
0.2654
0.5599


example 18y


Production
Yellow
575.3
38.0
0.497
434.8
3.2
15.1
2.16
2.86
0.2325
0.5647


example 19y


Production
Yellow
576.4
38.0
0.181
434.0
1.7
15.7
2.15
2.86
0.2382
0.5639


example 20y


Production
Yellow
582.7
40.9
0.485
546.1
3.2
18.1
2.13
2.27
0.2700
0.5592


example 21y


Production
Yellow
583.9
40.7
0.218
546.4
1.7
15.7
2.12
2.27
0.2767
0.5582


example 22y


Comparative
Yellow
580.1
39.2
0.506
347.0
3.2
14.6
2.14
3.56
0.2570
0.5611


production


example 1y


Comparative
Yellow
577.2
40.3
0.407
348.6
5.5
17.7
2.15
3.56
0.2419
0.5633


production


example 2y


Comparative
Yellow
577.2
37.9
0.786
349.3
5.4
14.6
2.15
3.56
0.2423
0.5633


production


example 3y


Comparative
Yellow
578.6
39.7
0.579
348.2
6.1
15.5
2.14
3.56
0.2492
0.5623


production


example 4y


Comparative
Yellow
577.5
42.2
0.208
367.2
1.7
16.5
2.15
3.39
0.2428
0.5632


production


example 5y


Comparative
Yellow
584.9
39.8
0.117
364.3
5.2
16.8
2.12
3.39
0.2828
0.5573


production


example 6y









Production Examples 1g to 22g
Productions of Various Green Luminescent Semiconductor Phosphor Microparticles
Using a method similar to that of Production example 1r, various green luminescent semiconductor phosphor microparticles of Production examples 1g to 22g were produced using Synthetic examples A1 to A12 and Synthetic examples B1 to B10, as shown in Table 1. As shown in Table 1, semiconductor phosphor microparticles of Comparative production examples 1g to 6g were also produced. Luminescence and absorption characteristics of these semiconductor phosphor microparticle are shown in Table 4.

















TABLE 4














Distribution






Emission
Emission

Shell
Core
of core
Core part
Shell part



















peak
half-value

absorption
particle
particle
bandgap
1 bandgap
Chromaticity


Production
Luminescent
wavelength
width
Luminous
wavelength
diameter
diameter
energy
energy
chart


















example
color
[nm]
[nm]
efficiency
[nm]
[nm]
[%]
[eV]
[eV]
u′
v′





















Production
Green
529.8
39.9
0.494
460.4
2.7
17.3
2.34
2.70
0.0663
0.5793


example 1g


Production
Green
528.8
56.8
0.471
457.4
2.7
27.6
2.35
2.70
0.0806
0.5691


example 2g


Production
Green
531.8
78.6
0.500
460.2
2.7
42.4
2.33
2.70
0.1104
0.5560


example 3g


Production
Green
530.4
37.9
0.523
458.6
2.7
13.4
2.34
2.70
0.0661
0.5803


example 4g


Production
Green
534.6
38.2
0.394
457.8
4.2
16.0
2.32
2.70
0.0771
0.5813


example 5g


Production
Green
529.6
41.8
0.416
458.0
3.4
18.3
2.34
2.70
0.0675
0.5783


example 6g


Production
Green
534.2
39.9
0.201
460.5
1.7
16.5
2.32
2.70
0.0772
0.5807


example 7g


Production
Green
528.6
60.7
0.235
461.7
1.7
28.7
2.35
2.70
0.0845
0.5662


example 8g


Production
Green
528.7
81.4
0.189
459.8
1.7
48.7
2.35
2.70
0.1079
0.5499


example 9g


Production
Green
533.4
37.5
0.185
459.4
1.7
15.2
2.32
2.70
0.0734
0.5813


example 10g


Production
Green
532.1
38.1
0.786
460.4
2.3
14.9
2.33
2.70
0.0704
0.5808


example 11g


Production
Green
528.7
40.4
0.604
459.2
2.6
17.0
2.35
2.70
0.0641
0.5785


example 12g


Production
Green
526.6
38.3
0.496
457.4
2.7
15.0
2.35
2.72
0.0575
0.5782


example 13g


Production
Green
530.1
40.5
0.175
457.3
1.7
17.9
2.34
2.72
0.0675
0.5791


example 14g


Production
Green
528.6
42.2
0.099
455.6
4.2
16.2
2.35
2.72
0.0656
0.5776


example 15g


Production
Green
534.4
39.6
0.108
456.2
2.4
16.8
2.32
2.72
0.0775
0.5808


example 16g


Production
Green
531.9
38.2
0.500
456.7
2.7
15.2
2.33
2.72
0.0700
0.5807


example 17g


Production
Green
530.9
42.5
0.221
456.8
1.7
17.8
2.34
2.72
0.0711
0.5786


example 18g


Production
Green
526.9
37.5
0.521
433.0
2.7
13.2
2.35
2.86
0.0577
0.5787


example 19g


Production
Green
534.6
42.1
0.178
432.7
1.7
18.6
2.32
2.86
0.0801
0.5800


example 20g


Comparative
Green
533.8
39.5
0.498
346.8
2.7
15.3
2.32
3.56
0.0760
0.5807


production


example 1g


Comparative
Green
529.1
38.7
0.403
346.9
4.2
14.3
2.34
3.56
0.0637
0.5794


production


example 2g


Comparative
Green
527.6
40.6
0.808
348.6
2.3
15.7
2.35
3.56
0.0619
0.5777


production


example 3g


Comparative
Green
527.3
38.2
0.584
347.3
2.6
14.7
2.35
3.56
0.0591
0.5787


production


example 4g


Comparative
Green
526.9
38.0
0.190
364.4
1.7
16.3
2.35
3.39
0.0580
0.5785


production


example 5g


Comparative
Green
530.4
38.8
0.109
367.1
4.2
15.9
2.34
3.39
0.0668
0.5799


production


example 6g









Production Examples 1b to 22b
Productions of Various Blue Luminescent Semiconductor Phosphor Microparticles
Using a method similar to that of Production example 1r, various blue luminescent semiconductor phosphor microparticles of Production examples 1b to 22b were produced using Synthetic examples A1 to A12 and Synthetic examples B1 to B10, as shown in Table 1. As shown in Table 1, semiconductor phosphor microparticles of Comparative production examples 1b to 6b were also produced. Luminescence and absorption characteristics of these semiconductor phosphor microparticle are shown in Table 5.

















TABLE 5














Distribution






Emission
Emission

Shell
Core
of core
Core part
Shell part



















peak
half-value

absorption
particle
particle
bandgap
band gap
Chromaticity


Production
Luminescent
wavelength
width
Luminous
wavelength
diameter
diameter
energy
energy
chart


















example
color
[nm]
[nm]
efficiency
[nm]
[nm]
[%]
[eV]
[eV]
u′
v′





















Production
Blue
477.6
42.1
0.512
458.9
2.1
16.7
2.60
2.70
0.1035
0.2698


example 1b


Production
Blue
482.6
62.4
0.511
457.6
2.1
29.4
2.57
2.70
0.0889
0.3515


example 2b


Production
Blue
479.4
81.2
0.495
459.4
2.1
47.8
2.59
2.70
0.1009
0.3563


example 3b


Production
Blue
478.5
41.8
0.475
458.8
2.1
18.6
2.59
2.70
0.0996
0.2788


example 4b


Production
Blue
477.2
38.0
0.419
458.1
3.3
15.5
2.60
2.70
0.1056
0.2581


example 5b


Production
Blue
476.2
41.8
0.410
457.8
2.8
15.7
2.60
2.70
0.1097
0.2546


example 6b


Production
Blue
477.9
38.3
0.192
458.0
1.4
14.3
2.59
2.70
0.1025
0.2660


example 7b


Production
Blue
478.9
60.0
0.234
458.1
1.4
27.4
2.59
2.70
0.0986
0.3159


example 8b


Production
Blue
479.3
78.6
0.210
460.6
1.4
49.5
2.59
2.70
0.1004
0.3516


example 9b


Production
Blue
481.6
42.0
0.207
459.4
1.4
17.7
2.57
2.70
0.0862
0.3134


example 10b


Production
Blue
483.4
41.8
0.820
458.7
1.9
18.6
2.57
2.70
0.0789
0.3325


example 11b


Production
Blue
479.3
38.8
0.583
458.2
2.0
16.9
2.59
2.70
0.0958
0.2828


example 12b


Production
Blue
480.2
42.4
0.498
457.7
2.1
18.1
2.58
2.72
0.0923
0.2983


example 13b


Production
Blue
484.3
41.9
0.224
457.3
1.4
16.2
2.56
2.72
0.0754
0.3426


example 14b


Production
Blue
477.8
39.7
0.077
455.8
3.3
15.2
2.60
2.72
0.1027
0.2678


example 15b


Production
Blue
481.0
37.9
0.116
456.7
1.8
14.4
2.58
2.72
0.0881
0.3003


example 16b


Production
Blue
484.5
41.8
0.509
455.9
2.1
18.1
2.56
2.72
0.0744
0.3450


example 17b


Production
Blue
484.6
41.9
0.206
455.5
1.4
15.7
2.56
2.72
0.0741
0.3465


example 18b


Production
Blue
478.4
41.8
0.481
433.6
2.1
17.9
2.59
2.86
0.1002
0.2773


example 19b


Production
Blue
480.8
40.2
0.188
432.5
1.4
14.8
2.58
2.86
0.0896
0.3010


example 20b


Comparative
Blue
482.3
40.5
0.501
349.6
2.1
16.5
2.57
3.56
0.0828
0.3193


production


example 1b


Comparative
Blue
484.4
39.1
0.379
347.2
3.3
16.2
2.56
3.56
0.0736
0.3413


production


example 2b


Comparative
Blue
477.4
41.0
0.813
349.1
1.9
18.0
2.60
3.56
0.1046
0.2652


production


example 3b


Comparative
Blue
478.1
39.3
0.582
348.4
2.0
14.7
2.59
3.56
0.1017
0.2694


production


example 4b


Comparative
Blue
481.5
38.2
0.194
365.9
1.4
16.0
2.58
3.39
0.0856
0.3072


production


example 5b


Comparative
Blue
476.8
39.4
0.080
367.1
3.3
16.9
2.60
3.39
0.1072
0.2566


production


example 6b









<<Variation in Absorption-Emission Spectrum Depending on Difference in Shell Part of Semiconductor Phosphor Microparticle>>

In the following, influence of the difference in shell part on the absorption-emission spectrum of the semiconductor phosphor microparticle will be examined. FIG. 17 shows an absorption-emission spectrum of an InP/ZnS semiconductor phosphor microparticle synthesized in Comparative production example 1r. FIG. 18 shows an absorption-emission spectrum of an InP/ZnSe semiconductor phosphor microparticle synthesized in Production example 1r. In both samples, measurement is conducted while concentration of the semiconductor phosphor microparticle is adjusted so that absorptance at 400 nm is about 90%.
FIG. 17 reveals that the InP/ZnS semiconductor phosphor microparticle synthesized in Comparative production example 1r shows an absorptance of 14.0% at 630.7 nm which is an emission peak of the InP core part, and an absorptance of 27.9% at 600 nm which is a skirt of the emission peak. On the other hand, FIG. 18 reveals that the InP/ZnSe semiconductor phosphor microparticle synthesized in Production example 1r shows an absorptance of 3.1% at 629.2 nm which is an emission peak of the InP core part, and an absorptance of 6.1% at 600 nm which is a skirt of the emission peak. In other words, it is found that the InP/ZnSe semiconductor phosphor microparticle has small absorptance at its own emission wavelength, in comparison with the InP/ZnS semiconductor phosphor microparticle.
This difference is considered to result from presence or absence of absorption of excitation light in the shell part. As shown in Table 2, bandgap of the ZnS shell part is 3.56 eV. Therefore, the ZnS shell part is able to absorb only the light having a wavelength smaller than 347.9 nm, and when excitation is caused with blue to UV light at 350 to 460 nm, the light needs to be absorbed in the InP core part. For this reason, it is necessary to increase the concentration of the InP core part, and absorptance in its own emission wavelength range increases. On the other hand, as shown in Table 2, bandgap of the ZnSe shell part is 2.70 eV. Therefore, the ZnSe shell part absorbs the light having a wavelength shorter than 459.2 nm. Therefore, when the InP/ZnS semiconductor phosphor microparticle is excited with blue to UV light at 350 to 450 nm, the light is absorbed in the shell part. As a result, it is possible to suppress the absorptance in the own emission wavelength range.
From the above, it is demonstrated that self absorption can be suppressed by making the shell part absorb the excitation light of the semiconductor phosphor microparticle. Less self absorption is preferred because susceptibility of concentration quenching decreases.
<<Examination of Influence of Absorptance of Semiconductor Phosphor Microparticle on Luminous Efficiency>>
In the following, influence of absorptance of the semiconductor phosphor microparticle on the luminous efficiency will be examined.
FIG. 19 is a graph showing dependency of luminous efficiency on absorptance in the InP/ZnS semiconductor phosphor microparticle synthesized in Comparative production example 1r and in the InP/ZnSe semiconductor phosphor microparticle synthesized in Production example 1r. In FIG. 19, the horizontal axis represents absorptance at 405 nm of phosphor, and the vertical axis represents luminous efficiency of phosphor when excited at 405 nm.
According to FIG. 19, in the InP/ZnS semiconductor phosphor microparticle synthesized in Comparative production example 1r, the luminous efficiency that is 49.7% at an absorptance of 9.1% decreases to the luminous efficiency of 42.8% at an absorptance of 91.9%, and the tendency that the luminous efficiency decreases as the absorptance increases is observed. On the other hand, in the InP/ZnSe semiconductor phosphor microparticle synthesized in Production example 1r, the luminous efficiency that is 51.8% at an absorptance of 25.2% is still 50.1% at an absorptance of 84.9%, and decrease in luminous efficiency is not observed.
This difference is attributable to difference in self absorption. In the InP/ZnS semiconductor phosphor microparticle in which the shell part allows transmission of excitation light, the influence of the self absorption is large, and decrease in luminous efficiency due to concentration quenching appears significantly. On the other hand, in the InP/ZnSe semiconductor phosphor microparticle in which excitation light is absorbed in the shell part, almost no decrease in luminous efficiency due to concentration quenching is observed. In other words, it was found that by making the shell part absorb excitation light of the semiconductor phosphor microparticle, influence of concentration quenching can be reduced.
<<Examination of Semiconductor Phosphor Microparticle Having a Multi-Shell Structure>>
In the following, a semiconductor phosphor microparticle having a multi-shell structure will be examined.
First, comparison will be made between the semiconductor phosphor microparticles synthesized in Production example 1r and in Production example 4r. Semiconductor phosphor microparticles synthesized in Production example 1r and in Production example 4r are identical in the point that they are InP/ZnSe semiconductor phosphor microparticles. They differ from each other only in the point that in Production example 4r, a multi-shell structure in which a SiO2 shell part is further provided outside the ZnSe shell part is employed.
The semiconductor phosphor microparticles synthesized in Production example 1r and in Production example 4r were aged for 30 days at 100° C. in an atmospheric environment, and decrease in luminous efficiency was observed. In the semiconductor phosphor microparticle of Production example 1r, decrease of 28.7% in luminous efficiency was observed after aging, while in the semiconductor phosphor microparticle of Production example 4r, decrease in luminous efficiency was only 7.4%. Similar tendency was observed also for the yellow phosphors of Production example 1y and Production example 4y, green phosphors of Production example 1g and Production example 4g, and blue phosphors of Production example 1b and Production example 4b.
Also comparison will be made between the semiconductor phosphor microparticles synthesized in Production example 7r and in Production example 10r. The semiconductor phosphor microparticles synthesized in Production example 7r and in Production example 10r are identical in the point that they are InN/ZnSe semiconductor phosphor microparticles. The semiconductor phosphor microparticles in production example 10r differs only in that it has a multi-shell structure in which a SiO2 shell part is further provided outside the ZnSe shell part.
Semiconductor phosphor microparticles synthesized in Production example 7r and in Production example 10r were aged for 30 days at 100° C. in an atmospheric environment, and decrease in luminous efficiency was observed. In the semiconductor phosphor microparticle of Production example 7r, decrease of 43.2% in luminous efficiency was observed after aging, while in the semiconductor phosphor microparticle of Production example 10r, decrease in luminous efficiency was only 19.4%.
Similar tendency was observed also for the yellow phosphors of Production example 7y and Production example 10y, green phosphors of Production example 7g and Production example 10g, and blue phosphors of Production example 7b and Production example 10b.
This is attributable to the fact that by adding a chemically stable SiO2 shell part, influence of water, oxygen and the like on the core part and the shell part is alleviated. From these results, it was confirmed that durability of a semiconductor phosphor microparticle can be improved by employing a multi-shell structure made up of a plurality of shell parts.
<<Effect of Using Mixed Crystal Semiconductor Material for Core Part of Semiconductor Phosphor Microparticle>>
In the following, a semiconductor phosphor microparticle using a mixed crystal material will be examined.
Production example 1r, Production example 5r and Production example 6r are synthesized in the same manner except for the core part. The difference is that in Production example 1r, an InP material having a particle diameter of 3.8 nm is used for the core part, while in Production example 5r, an In0.5Ga0.5P mixed crystal material having a particle diameter of 6.1 nm is used, and in Production example 6r, an In0.7Ga0.3P mixed crystal material having a particle diameter of 5.4 nm is used. From Table 2, it can be seen that in any of the semiconductor phosphor microparticles fabricated in these production methods, emission wavelength is 630 nm.
Production example 14r, Production example 15r, and Production example 16r are synthesized in the same manner except for the core part. The difference is that in Production example 14r, an InN material having a particle diameter of 2.0 nm is used for the core part, while in Production example 15r, an In0.6Ga0.4N mixed crystal material having a particle diameter of 6.0 nm is used, and in Production example 16r, an In0.8Ga0.2N mixed crystal material having a particle diameter of 3.4 nm is used. From Table 2, it can be seen that in any of the semiconductor phosphor microparticles fabricated in these production methods, emission wavelength is 630 nm.
Similar tendency was observed also in Production example 1y and Production example 5y and Production example 6y, Production example 1g and Production example 5g and Production example 6g, Production example 1b and Production example 5b and Production example 6y, Production example 14y and Production example 15y and Production example 16y, Production example 14g and Production example 15g and Production example 16g, Production example 14b and Production example 15b and Production example 16b. That is, it was found that by using a mixed crystal semiconductor material for a core part of the semiconductor phosphor microparticle, emission wavelength of the phosphor can be controlled not only by the particle diameter but also by the mixed crystal ratio.
<Fabrication of Light Emitting Device>
In the following, a method of producing a light emitting device including a light emitting element, and a semiconductor phosphor microparticle of a core/shell structure having a shell part absorbing at least a part of the light emitted from the light emitting element will be described. Further, in the following examples, for measuring chromaticity point, luminous efficiency and color rendering property index of a light emitting device, a luminescence measuring system MCPD-7000 (available from OTSUKA ELECTRONICS CO. LTD.) was used.
Examples A1
Light Emitting Device Including InP/ZnSe Red Phosphor, InP/ZnSe Green Phosphor, and Blue Luminescent Semiconductor Diode Element
In Example A1, a method of producing a light emitting device including an InP/ZnSe red phosphor, an InP/ZnSe green phosphor, and a blue luminescent semiconductor diode element will be described.
First, a red phosphor fabricated by Production example A1, and a green phosphor fabricated by Production example B1 were mixed in such a weight ratio that the weight of green phosphor was 0.883, with respect to the weight of the red phosphor of 0.117, as shown in “Weight mixing ratio of various phosphors” in Table 6, to obtain a phosphor mixture.
This phosphor mixture was dispersed in silicone resin so that the red phosphor and the green phosphor were dispersed such that the weight of the silicone resin was 101.8, relative to 1 of the weight of the phosphor mixture, as shown in “Phosphor/resin weight mixing ratio” in Table 6, to obtain mold resin.
Next, using the mold resin obtained above, a blue semiconductor light emitting diode element having an InGaN semiconductor active layer having an emission peak wavelength at 450 was sealed, and a light emitting device of Example 1 having the structure as shown in FIG. 1 was fabricated.
Chromaticity point, luminous efficiency and color rendering property index of the light emitting device fabricated in Example A1 are shown in Table 7. The light emitting device fabricated in Example A1 was proved to exhibit white color of chromaticity point(u′, v′)=(0.1999, 0.3967). The color rendering property index was proved to be 46.4. Taking luminous efficiency of this light emitting device as a standard, luminous efficiency of a light emitting device fabricated hereinafter was determined as a relative value, relative to the luminous efficiency of this light emitting device as 100%.









TABLE 6









Configuration of light emitting device









Synthetic method of phosphor for use
















Red
Yellow
Green
Blue


Example
Structure
Light-emitting element
phosphor
phosphor
phosphor
phosphor





Example A1
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 1r

example 1g


Example A2
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 2r

example 2g


Example A3
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 3r

example 3g


Example A4
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 4r

example 4g


Example A5
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 5r

example 5g


Example A6
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 6r

example 6g


Example A7
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 7r

example 7g


Example A8
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 8r

example 8g


Example A9
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 9r

example 9g


Example A10
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 10r

example 10g


Example A11
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 11r

example 11g


Example A12
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 12r

example 12g


Example A13
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 13r

example 13g


Example A14
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 14r

example 14g


Example A15
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 15r

example 15g


Example A16
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 16r

example 16g


Example A17
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 17r

example 17g


Example A18
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 18r

example 18g


Example A19
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 21r

example 1g


Example A20
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 22r

example 7g


Example A21
Light-emitting
Blue semiconductor light
—
Production
—
—



device 1
emitting diode element

example 1y


Example A22
Light-emitting
Blue semiconductor light
—
Production
—
—



device 1
emitting diode element

example 7y


Example A23
Light-emitting
Blue semiconductor light
Production
Production
Production
—



device 1
emitting diode element
example 1r
example 1y
example 1g


Example A24
Light-emitting
Blue semiconductor light
Production
Production
Production
—



device 1
emitting diode element
example 7r
example 7y
example 7g


Example A25
Light-emitting
Blue semiconductor light
Production
—
Production
Production



device 1
emitting diode element
example 1r

example 1g
example 1b


Example A26
Light-emitting
Blue semiconductor light
Production
—
Production
Production



device 1
emitting diode element
example 7r

example 7g
example 7b


Example A27
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 1r

example 7g


Example A28
Light-emitting
Blue semiconductor light
Production
—
Production
—



device 1
emitting diode element
example 5r

example 11g


Example A29
Light-emitting
Blue semiconductor light
Production
—
—
—



device 1
emitting diode element
example 1r


Example A30
Light-emitting
Blue semiconductor light
—
—
Production
—



device 1
emitting diode element


example 1g


Example A31
Light-emitting
Blue semiconductor light
—
—
—
Production



device 1
emitting diode element



example 1b


Comparative
Light-emitting
Blue semiconductor light
Comparative
—
Comparative
—


Example A1
device 1
emitting diode element
Production

Production





example 1r

example 1g


Comparative
Light-emitting
Blue semiconductor light
Comparative
—
Comparative
—


Example A2
device 1
emitting diode element
Production

Production





example 2r

example 2g


Comparative
Light-emitting
Blue semiconductor light
Comparative
—
Comparative
—


Example A3
device 1
emitting diode element
Production

Production





example 3r

example 3g


Comparative
Light-emitting
Blue semiconductor light
Comparative
—
Comparative
—


Example A4
device 1
emitting diode element
Production

Production





example 4r

example 4g


Comparative
Light-emitting
Blue semiconductor light
Comparative
—
Comparative
—


Example A5
device 1
emitting diode element
Production

Production





example 5r

example 5g


Comparative
Light-emitting
Blue semiconductor light
Comparative
—
Comparative
—


Example A6
device 1
emitting diode element
Production

Production





example 6r

example 6g












Fabrication method of light emitting device









Phosphor/resin










Mixing ratio of various phosphors
weight mixing ratio
















Red
Yellow
Green
Blue
Phosphor




Example
phosphor
phosphor
phosphor
phosphor
mixture
Resin







Example A1
0.117
—
0.883
—
1.000
101.8



Example A2
0.112
—
0.888
—
1.000
90.5



Example A3
0.100
—
0.900
—
1.000
78.1



Example A4
0.116
—
0.884
—
1.000
103.3



Example A5
0.106
—
0.894
—
1.000
77.0



Example A6
0.129
—
0.871
—
1.000
73.7



Example A7
0.112
—
0.888
—
1.000
35.0



Example A8
0.115
—
0.885
—
1.000
34.9



Example A9
0.141
—
0.859
—
1.000
42.6



Example A10
0.123
—
0.877
—
1.000
39.5



Example A11
0.120
—
0.880
—
1.000
161.7



Example A12
0.123
—
0.877
—
1.000
123.2



Example A13
0.127
—
0.873
—
1.000
104.3



Example A14
0.120
—
0.880
—
1.000
39.5



Example A15
0.122
—
0.878
—
1.000
16.5



Example A16
0.117
—
0.883
—
1.000
23.1



Example A17
0.128
—
0.872
—
1.000
99.1



Example A18
0.124
—
0.876
—
1.000
38.0



Example A19
0.117
—
0.883
—
1.000
99.7



Example A20
0.130
—
0.870
—
1.000
35.0



Example A21
—
1.000
—
—
1.000
176.0



Example A22
—
1.000
—
—
1.000
57.1



Example A23
0.076
0.323
0.601
—
1.000
123.9



Example A24
0.076
0.323
0.600
—
1.000
42.2



Example A25
0.064
—
0.358
0.577
1.000
33.0



Example A26
0.062
—
0.368
0.570
1.000
11.1



Example A27
0.111
—
0.889
—
1.000
103.7



Example A28
0.110
—
0.890
—
1.000
76.6



Example A29
1.000
—
—
—
1.000
99.9



Example A30
—
—
1.000
—
1.000
13.2



Example A31
—
—
—
1.000
1.000
11.7



Comparative
0.114
—
0.886
—
1.000
98.8



Example A1



Comparative
0.128
—
0.872
—
1.000
77.5



Example A2



Comparative
0.112
—
0.888
—
1.000
157.9



Example A3



Comparative
0.124
—
0.876
—
1.000
113.3



Example A4



Comparative
0.135
—
0.865
—
1.000
36.2



Example A5



Comparative
0.118
—
0.882
—
1.000
18.0



Example A6




















TABLE 7









Structure of light emitting device
Characteristics of light emitting device













Excitation light
Bandgap energy of






energy from light
semiconductor particle
Chromaticity

Color rendering



emitting element
phosphor shell part
point
Brightness
property index













Example
[eV]
[eV]
u′
v′
[%]
(Ra)
















Example A1
2.76
2.70
0.1999
0.3967
100.0%
46.4


Example A2
2.76
2.70
0.2008
0.4020
98.9%
66.2


Example A3
2.76
2.70
0.2005
0.4073
101.4%
81.9


Example A4
2.76
2.70
0.1996
0.3965
103.3%
46.9


Example A5
2.76
2.70
0.1977
0.3991
88.3%
57.4


Example A6
2.76
2.70
0.2000
0.3970
79.4%
42.4


Example A7
2.76
2.70
0.1977
0.3992
47.0%
53.6


Example A8
2.76
2.70
0.2008
0.4020
49.0%
61.1


Example A9
2.76
2.70
0.2184
0.3907
45.0%
64.2


Example A10
2.76
2.70
0.1996
0.3968
45.8%
48.0


Example A11
2.76
2.70
0.2006
0.3958
135.3%
46.9


Example A12
2.76
2.70
0.2040
0.3932
111.2%
41.6


Example A13
2.76
2.72
0.2050
0.3915
95.7%
33.9


Example A14
2.76
2.72
0.2003
0.3965
44.7%
46.6


Example A15
2.76
2.72
0.2021
0.3951
22.6%
41.4


Example A16
2.76
2.72
0.1965
0.4004
29.0%
53.8


Example A17
2.76
2.72
0.2001
0.3961
96.1%
43.4


Example A18
2.76
2.72
0.2031
0.3943
47.2%
42.4


Example A19
2.76
2.27
0.2002
0.3967
79.5%
50.4


Example A20
2.76
2.27
0.2012
0.3949
41.7%
37.2


Example A21
2.76
2.70
0.2416
0.3835
144.7%
40.3


Example A22
2.76
2.70
0.2307
0.3936
73.0%
40.8


Example A23
2.76
2.70
0.2167
0.3922
99.4%
73.5


Example A24
2.76
2.70
0.2120
0.3967
47.6%
75.9


Example A25
2.76
2.70
0.2013
0.4032
68.6%
36.3


Example A26
2.76
2.70
0.1993
0.4057
29.0%
45.2


Example A27
2.76
2.70
0.1980
0.3990
68.2%
54.7


Example A28
2.76
2.70
0.1989
0.3976
105.8%
52.8


Example A29
2.76
2.70
0.4393
0.4454
—
—


Example A30
2.76
2.70
0.0675
0.5455
—
—


Example A31
2.76
2.70
0.1127
0.3095
—
—


Comparative
2.76
3.56
0.1981
0.3986
76.8%
51.9


Example A1


Comparative
2.76
3.56
0.2002
0.3960
60.2%
40.3


Example A2


Comparative
2.76
3.56
0.2009
0.3960
98.8%
45.9


Example A3


Comparative
2.76
3.56
0.2010
0.3953
78.1%
40.2


Example A4


Comparative
2.76
3.39
0.2013
0.3947
29.4%
33.6


Example A5


Comparative
2.76
3.39
0.1996
0.3967
19.3%
46.0


Example A6









Examples A2 to A31, Comparative Examples A1 to A6
Light Emitting Devices Including Various Phosphors, and Blue Luminescent Semiconductor Diode Element
A method of producing a light emitting device including various semiconductor phosphor microparticles, and a blue luminescent semiconductor diode element will be described. Light emitting devices of Examples A2 to A31 and Comparative examples A1 to A6 were fabricated in a similar manner as that of Example A1 except for the kind and the quantity of various phosphors and the quantity of the silicone resin. Concretely, similarly to Example A1, various phosphors were mixed in a weight ratio shown in “Weight mixing ratio of various phosphors” of Table 6, to obtain a phosphor mixture. Then the phosphor mixture and the silicone resin were mixed in a mixing ratio shown in “Phosphor/resin weight mixing ratio” of Table 6, to obtain mold resin.
Next, using the mold resin obtained above, a blue semiconductor light emitting diode element having an InGaN semiconductor active layer having an emission peak wavelength of 450 nm was sealed, and a light emitting device of Examples A2 to A31, and Comparative examples A1 to A6 having the structure as shown in FIG. 1 was fabricated. The light emitting devices produced in these methods were evaluated, and chromaticity point, luminous efficiency and color rendering property index shown in Table 7 were determined.
Examples B1 to B4, Comparative Examples B1 to B2
Light Emitting Devices Including Various Phosphors, and UV Luminescent Semiconductor Diode Element
A method of producing a light emitting device including various semiconductor phosphor microparticles, and a UV luminescent semiconductor diode element will be described. Light emitting devices of Examples B1 to B4 and Comparative examples B1 to B2 were fabricated in a similar manner as that of Example A1 except for the kind and the quantity of various phosphors, the quantity of the silicone resin and use of a UV luminescent semiconductor diode element as a light emitting element. Concretely, similarly to Example A1, various phosphors were mixed in a weight ratio shown in “Weight mixing ratio of various phosphors” of Table 8, to obtain a phosphor mixture. Then the phosphor mixture and the silicone resin were mixed in a mixing ratio shown in “Phosphor/resin weight mixing ratio” of Table 8, to obtain mold resin.
Next, using the mold resin obtained above, a UV semiconductor light emitting diode element having an InGaN semiconductor active layer having emission peak wavelength of 380 nm was sealed, and light emitting devices of Examples B1 to B4, and Comparative examples B1 to B2 having the structure as shown in FIG. 1 were fabricated. The light emitting devices produced in these methods were evaluated, and chromaticity point, luminous efficiency and color rendering property index shown in Table 9 were determined.









TABLE 8









Configuration of light emitting device









Synthetic method of phosphor for use
















Red
Yellow
Green
Blue


Example
Structure
Light emitting element
phosphor
phosphor
phosphor
phosphor





Example B1
Light emitting
UV semiconductor light
Production
—
Production
Production



device 1
emitting diode element
example 1r

example 1g
example 1b


Example B2
Light emitting
UV semiconductor light
Production
—
Production
Production



device 1
emitting diode element
example 7r

example 7g
example 7b


Example B3
Light emitting
UV semiconductor light
Production
—
Production
Production



device 1
emitting diode element
example 19r

example 19g
example 19b


Example B4
Light emitting
UV semiconductor light
Production
—
Production
Production



device 1
emitting diode element
example 20r

example 20g
example 20b


Comparative
Light emitting
UV semiconductor light
Comparative
—
Comparative
Comparative


Example B1
device 1
emitting diode element
Production

Production
Production





example 1r

example 1g
example 1b


Comparative
Light emitting
UV semiconductor light
Comparative
—
Comparative
Comparative


Example B2
device 1
emitting diode element
Production

Production
Production





example 5r

example 5g
example 5b












Fabrication method of light emitting device









Phosphor/resin










Mixing ratio of various phosphors
weight mixing ratio
















Red
Yellow
Green
Blue
Phosphor




Example
phosphor
phosphor
phosphor
phosphor
mixture
Resin







Example B1
0.039
—
0.117
0.844
1.000
11.7



Example B2
0.039
—
0.129
0.832
1.000
3.9



Example B3
0.045
—
0.112
0.843
1.000
10.9



Example B4
0.038
—
0.085
0.877
1.000
4.9



Comparative
0.040
—
0.065
0.895
1.000
11.9



Example B1



Comparative
0.045
—
0.084
0.871
1.000
4.5



Example B2




















TABLE 9









Structure of light emitting device
Characteristics of light emitting device













Excitation light
Bandgap energy of






energy from light
semiconductor particle
Chromaticity

Color rendering



emitting element
phosphor shell part
point
Brightness
property index













Example
[eV]
[eV]
u′
v′
[%]
(Ra)
















Example B1
3.26
2.70
0.2037
0.4157
85.9%
−1.8


Example B2
3.26
2.70
0.2016
0.4189
34.2%
6.5


Example B3
3.26
2.86
0.2049
0.4152
76.6%
−14.3


Example B4
3.26
2.86
0.2048
0.4196
35.0%
−10.2


Comparative
3.26
3.56
0.2064
0.4193
51.5%
−25.5


Example B1


Comparative
3.26
3.39
0.2065
0.4191
30.4%
−31.9


Example B2









Examples C1 to C2, Comparative Examples C1 to C2
Light Emitting Devices Including Various Phosphors, and Blue Luminescent Semiconductor Laser Diode Element
A method of producing a light emitting device including various semiconductor phosphor microparticles, and a blue luminescent semiconductor laser diode element will be described. Light emitting devices of Examples C1 to C2 and Comparative examples C1 to C2 were fabricated in a similar manner as that of Example A1 except for the kind and the quantity of various phosphors, the quantity of the silicone resin and use of a blue luminescent semiconductor laser diode element as a light emitting element. Concretely, similarly to Example A1, various phosphors were mixed in a weight ratio shown in “Weight mixing ratio of various phosphors” of Table 10, to obtain a phosphor mixture. Then the phosphor mixture and the silicone resin were mixed in a mixing ratio shown in “Phosphor/resin weight mixing ratio” of Table 10, to obtain mold resin.
Next, using the mold resin obtained above, a blue semiconductor light emitting laser diode element having an InGaN semiconductor active layer having emission peak wavelength of 450 nm was sealed, and light emitting devices of Examples C1 to C2 and Comparative examples C1 to C2 having the structure as shown in FIG. 2 were fabricated, The light emitting devices produced in these methods were evaluated, and chromaticity point, luminous efficiency and color rendering property index shown in Table 11 were determined









TABLE 10









Configuration of light emitting device









Synthetic method of phosphor for use
















Red
Yellow
Green
Blue


Example
Structure
Light emitting element
phosphor
phosphor
phosphor
phosphor





Example C1
Light emitting
Blue semiconductor light
Production
—
Production
—



device 21
emitting laser diode element
example 1r

example 1g


Example C2
Light emitting
Blue semiconductor light
Production
—
Production
—



device 21
emitting laser diode element
example 7r

example 7g


Comparative
Light emitting
Blue semiconductor light
Comparative
—
Comparative
—


Example C1
device 21
emitting laser diode element
Production

Production





example 1r

example 1g


Comparative
Light emitting
Blue semiconductor light
Comparative
—
Comparative
—


Example C2
device 21
emitting laser diode element
Production

Production





example 5r

example 5g












Fabrication method of light emitting device









Phosphor/resin










Mixing ratio of various phosphors
weight mixing ratio
















Red
Yellow
Green
Blue
Phosphor




Example
phosphor
phosphor
phosphor
phosphor
mixture
Resin







Example C1
0.113
—
0.887
—
1.000
90.9



Example C2
0.108
—
0.892
—
1.000
31.4



Comparative
0.109
—
0.891
—
1.000
88.3



Example C1



Comparative
0.130
—
0.870
—
1.000
32.3



Example C2




















TABLE 11









Structure of light emitting device
Characteristics of light emitting device













Excitation light
Bandgap energy of






energy from light
semiconductor particle
Chromaticity

Color rendering



emitting element
phosphor shell part
point
Brightness
property index













Example
[eV]
[eV]
u′
v′
[%]
(Ra)
















Example C1
2.76
2.70
0.1997
0.3982
52.2%
47.0


Example C2
2.76
2.70
0.1977
0.4005
24.3%
52.8


Comparative
2.76
3.56
0.1978
0.4002
37.7%
51.6


Example C1


Comparative
2.76
3.39
0.2011
0.3963
15.8%
34.7


Example C2









Examples D1 to D4, Comparative Examples D1 to D2
Light Emitting Devices Including Various Phosphors, and UV Luminescent Semiconductor Laser Diode Element
A method of producing a light emitting device including various semiconductor phosphor microparticles, and a UV luminescent semiconductor laser diode element will be described. Light emitting devices of Examples D1 to D4 and Comparative examples D1 to D2 were fabricated in a similar manner as that of Example A1 except for the kind and the quantity of various phosphors, the quantity of the silicone resin and use of a UV luminescent semiconductor laser diode element as a light emitting element. Concretely, similarly to Example A1, various phosphors were mixed in a weight ratio shown in “Weight mixing ratio of various phosphors” of Table 12, to obtain a phosphor mixture. Then the phosphor mixture and the silicone resin were mixed in a mixing ratio shown in “Phosphor/resin weight mixing ratio” of Table 12, to obtain mold resin.
Next, using the mold resin obtained above, a UV semiconductor light emitting laser diode element having an InGaN semiconductor active layer having emission peak wavelength of 380 nm was sealed, and light emitting devices of Examples D1 to D4 and Comparative examples D1 to D2 having the structure as shown in FIG. 2 were fabricated, The light emitting devices produced in these methods were evaluated, and chromaticity point, luminous efficiency and color rendering property index shown in Table 13 were determined.









TABLE 12









Configuration of light emitting device









Synthetic method of phosphor for use
















Red
Yellow
Green
Blue


Example
Structure
Light emitting element
phosphor
phosphor
phosphor
phosphor





Example D1
Light emitting
UV semiconductor light
Production
—
Production
Production



device 21
emitting laser diode element
example 1r

example 1g
example 1b


Example D2
Light emitting
UV semiconductor light
Production
—
Production
Production



device 21
emitting laser diode element
example 7r

example 7g
example 7b


Example D3
Light emitting
UV semiconductor light
Production
—
Production
Production



device 21
emitting laser diode element
example 19r

example 19g
example 19b


Example D4
Light emitting
UV semiconductor light
Production
—
Production
Production



device 21
emitting laser diode element
example 20r

example 20g
example 20b


Comparative
Light emitting
UV semiconductor light
Comparative
—
Comparative
Comparative


Example D1
device 21
emitting laser diode element
Production

Production
Production





example 1r

example 1g
example 1b


Comparative
Light emitting
UV semiconductor light
Comparative
—
Comparative
Comparative


Example D2
device 21
emitting laser diode element
Production

Production
Production





example 5r

example 5g
example 5b












Fabrication method of light emitting device









Phosphor/resin










Mixing ratio of various phosphors
weight mixing ratio
















Red
Yellow
Green
Blue
Phosphor




Example
phosphor
phosphor
phosphor
phosphor
mixture
Resin







Example D1
0.039
—
0.106
0.855
1.000
11.8



Example D2
0.039
—
0.129
0.832
1.000
3.9



Example D3
0.045
—
0.117
0.838
1.000
10.8



Example D4
0.038
—
0.085
0.877
1.000
4.9



Comparative
0.040
—
0.073
0.887
1.000
11.8



Example D1



Comparative
0.045
—
0.084
0.871
1.000
4.5



Example D2




















TABLE 13









Structure of light emitting device
Characteristics of light emitting device













Excitation light
Bandgap energy of






energy from light
semiconductor particle
Chromaticity

Color rendering



emitting element
phosphor shell part
point
Brightness
property index













Example
[eV]
[eV]
u′
v′
[%]
(Ra)
















Example D1
3.26
2.70
0.2044
0.4162
84.3%
−6.6


Example D2
3.26
2.70
0.2016
0.4189
34.2%
6.5


Example D3
3.26
2.86
0.2047
0.4148
77.3%
−12.2


Example D4
3.26
2.86
0.2048
0.4196
35.0%
−10.2


Comparative
3.26
3.56
0.2058
0.4190
51.6%
−21.4


Example D1


Comparative
3.26
3.39
0.2065
0.4191
20.6%
−31.9


Example D2









Examples E1 to E27, Comparative Examples E1 to E6
Light Emitting Devices Including Various Phosphors, and Blue Organic Electroluminescence Element
A method of producing a light emitting device including various semiconductor phosphor microparticle, and a organic electroluminescence element will be described. Light emitting devices of Examples E1 to E27 and Comparative examples E1 to E6 were fabricated in a similar manner as that of Example A1 except for the kind and the quantity of various phosphors, the quantity of the silicone resin and use of a blue organic electroluminescence element as a light emitting element. Concretely, similarly to Example A1, various phosphors were mixed in a weight ratio shown in “Weight mixing ratio of various phosphors” of Table 14, to obtain a phosphor mixture. Then the phosphor mixture and the silicone resin were mixed in a mixing ratio shown in “Phosphor/resin weight mixing ratio” of Table 14, to obtain mold resin.
Next, using the mold resin obtained above, a blue organic electroluminescence element having emission peak wavelength of 455 nm was sealed, and light emitting devices of Examples E1 to E27 and Comparative examples E1 to E6 having the structure as shown in FIG. 3 were fabricated. The light emitting devices produced in these methods were evaluated, and chromaticity point, luminous efficiency and color rendering property index shown in Table 15 were determined.









TABLE 14









Configuration of light emitting device









Synthetic method of phosphor for use
















Red
Yellow
Green
Blue


Example
Structure
Light emitting element
phosphor
phosphor
phosphor
phosphor





Example E1
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 1r

example 1g


Example E2
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 2r

example 2g


Example E3
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 3r

example 3g


Example E4
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 4r

example 4g


Example E5
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 5r

example 5g


Example E6
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 6r

example 6g


Example E7
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 7r

example 7g


Example E8
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 8r

example 8g


Example E9
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 9r

example 9g


Example E10
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 10r

example 10g


Example E11
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 11r

example 11g


Example E12
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 12r

example 12g


Example E13
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 13r

example 13g


Example E14
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 14r

example 14g


Example E15
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 15r

example 15g


Example E16
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 16r

example 16g


Example E17
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 17r

example 17g


Example E18
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 18r

example 18g


Example E19
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 21r

example 1g


Example E20
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 22r

example 7g


Example E21
Light emitting
Blue organic electro-
Production
—
Production
Production



device 41
luminescence element
example 1r

example 1g
example 1b


Example E22
Light emitting
Blue organic electro-
Production
—
Production
Production



device 41
luminescence element
example 7r

example 7g
example 7b


Example E23
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 1r

example 7g


Example E24
Light emitting
Blue organic electro-
Production
—
Production
—



device 41
luminescence element
example 5r

example 11g


Example E25
Light emitting
Blue organic electro-
Production
—
—
—



device 41
luminescence element
example 1r


Example E26
Light emitting
Blue organic electro-
—
—
Production
—



device 41
luminescence element


example 1g


Example E27
Light emitting
Blue organic electro-
—
—
—
Production



device 41
luminescence element



example 1b


Comparative
Light emitting
Blue organic electro-
Comparative
—
Comparative
—


Example E1
device 41
luminescence element
Production

Production





example 1r

example 1g


Comparative
Light emitting
Blue organic electro-
Comparative
—
Comparative
—


Example E2
device 41
luminescence element
Production

Production





example 2r

example 2g


Comparative
Light emitting
Blue organic electro-
Comparative
—
Comparative
—


Example E3
device 41
luminescence element
Production

Production





example 3r

example 3g


Comparative
Light emitting
Blue organic electro-
Comparative
—
Comparative
—


Example E4
device 41
luminescence element
Production

Production





example 4r

example 4g


Comparative
Light emitting
Blue organic electro-
Comparative
—
Comparative
—


Example E5
device 41
luminescence element
Production

Production





example 5r

example 5g


Comparative
Light emitting
Blue organic electro-
Comparative
—
Comparative
—


Example E6
device 41
luminescence element
Production

Production





example 6r

example 6g












Fabrication method of light emitting device









Phosphor/resin










Mixing ratio of various phosphors
weight mixing ratio
















Red
Yellow
Green
Blue
Phosphor




Example
phosphor
phosphor
phosphor
phosphor
mixture
Resin







Example E1
0.122
—
0.878
—
1.000
123.6



Example E2
0.114
—
0.886
—
1.000
114.7



Example E3
0.101
—
0.899
—
1.000
103.9



Example E4
0.121
—
0.879
—
1.000
125.4



Example E5
0.114
—
0.886
—
1.000
96.7



Example E6
0.134
—
0.866
—
1.000
89.4



Example E7
0.122
—
0.878
—
1.000
43.9



Example E8
0.117
—
0.883
—
1.000
44.0



Example E9
0.099
—
0.901
—
1.000
43.4



Example E10
0.129
—
0.871
—
1.000
48.3



Example E11
0.124
—
0.876
—
1.000
195.1



Example E12
0.121
—
0.879
—
1.000
143.4



Example E13
0.123
—
0.877
—
1.000
118.9



Example E14
0.125
—
0.875
—
1.000
47.9



Example E15
0.123
—
0.877
—
1.000
19.6



Example E16
0.129
—
0.871
—
1.000
29.3



Example E17
0.133
—
0.867
—
1.000
119.8



Example E18
0.123
—
0.877
—
1.000
44.8



Example E19
0.122
—
0.878
—
1.000
121.6



Example E20
0.133
—
0.867
—
1.000
41.6



Example E21
0.078
—
0.503
0.419
1.000
61.5



Example E22
0.076
—
0.490
0.434
1.000
20.6



Example E23
0.119
—
0.881
—
1.000
129.7



Example E24
0.116
—
0.884
—
1.000
94.4



Example E25
1.000
—
—
—
1.000
116.5



Example E26
—
—
1.000
—
1.000
14.9



Example E27
—
—
—
1.000
1.000
16.9



Comparative
0.123
—
0.877
—
1.000
123.1



Example E1



Comparative
0.133
—
0.867
—
1.000
93.3



Example E2



Comparative
0.115
—
0.885
—
1.000
189.7



Example E3



Comparative
0.126
—
0.874
—
1.000
135.0



Example E4



Comparative
0.138
—
0.862
—
1.000
42.8



Example E5



Comparative
0.124
—
0.876
—
1.000
21.9



Example E6




















TABLE 15









Structure of light emitting device
Characteristics of light emitting device













Excitation light
Bandgap energy of






energy from light
semiconductor particle
Chromaticity

Color rendering



emitting element
phosphor shell part
point
Brightness
property index













Example
[eV]
[eV]
u′
v′
[%]
(Ra)
















Example E1
2.73
2.70
0.1937
0.4069
66.4%
50.4


Example E2
2.73
2.70
0.1931
0.4074
65.4%
70.9


Example E3
2.73
2.70
0.1927
0.4076
66.0%
86.4


Example E4
2.73
2.70
0.1936
0.4068
68.5%
50.8


Example E5
2.73
2.70
0.1936
0.4064
58.3%
60.3


Example E6
2.73
2.70
0.1937
0.4071
53.2%
46.4


Example E7
2.73
2.70
0.1937
0.4065
31.7%
56.0


Example E8
2.73
2.70
0.1932
0.4076
33.4%
65.8


Example E9
2.73
2.70
0.1926
0.4080
31.8%
85.3


Example E10
2.73
2.70
0.1938
0.4065
31.2%
52.3


Example E11
2.73
2.70
0.1937
0.4066
88.4%
52.1


Example E12
2.73
2.70
0.1936
0.4071
74.7%
50.3


Example E13
2.73
2.72
0.1936
0.4072
65.1%
43.6


Example E14
2.73
2.72
0.1937
0.4069
30.6%
51.2


Example E15
2.73
2.72
0.1936
0.4072
15.8%
47.8


Example E16
2.73
2.72
0.1938
0.4064
19.7%
54.9


Example E17
2.73
2.72
0.1939
0.4068
63.9%
47.8


Example E18
2.73
2.72
0.1937
0.4069
32.6%
50.2


Example E19
2.73
2.27
0.1937
0.4065
52.7%
55.5


Example E20
2.73
2.27
0.1939
0.4070
28.4%
42.6


Example E21
2.73
2.70
0.1929
0.4100
49.9%
47.2


Example E22
2.73
2.70
0.1928
0.4100
21.8%
53.1


Example E23
2.73
2.70
0.1936
0.4066
46.2%
57.6


Example E24
2.73
2.70
0.1936
0.4066
69.1%
56.2


Example E25
2.73
2.70
0.5020
0.4604
—
—


Example E26
2.73
2.70
0.0726
0.5458
—
—


Example E27
2.73
2.70
0.1141
0.3090
—
—


Comparative
2.73
3.56
0.1937
0.4065
50.3%
54.5


Example E1


Comparative
2.73
3.56
0.1938
0.4070
39.9%
44.6


Example E2


Comparative
2.73
3.56
0.1935
0.4071
66.1%
51.0


Example E3


Comparative
2.73
3.56
0.1936
0.4072
51.9%
45.5


Example E4


Comparative
2.73
3.39
0.1939
0.4073
20.1%
39.0


Example E5


Comparative
2.73
3.39
0.1937
0.4068
12.9%
49.7


Example E6









<<Examination by Difference in Bandgap of Shell Part Material>>

In the following, influence of the difference in material of shell part of the semiconductor phosphor microparticle on the luminous efficiency of the light emitting device will be examined.
FIG. 20, FIG. 21 and FIG. 22 are charts showing relations of brightness of light emitting devices 1, 21, 41 using various semiconductor phosphor microparticles having a core/shell structure. The horizontal axis represents bandgap energy of shell part of semiconductor phosphor microparticle, and the vertical axis plots relative value of luminous efficiency of light emitting device. Here, as an excitation light source, a blue semiconductor light emitting diode element and a blue semiconductor light emitting laser diode element are used in FIG. 20, a UV semiconductor light emitting diode element and a UV semiconductor light emitting laser diode element are used in FIG. 21, and a blue electroluminescence element is used in FIG. 22. The straight line in the drawing represents energy of excitation light emitted from the light source. In every case of FIG. 20 to FIG. 22, it is found that luminous efficiency is high when bandgap energy of a shell part material is smaller than excitation light energy of the light source. This is attributable to the fact that concentration quenching of the semiconductor phosphor microparticle can be suppressed by absorbing excitation light in the shell part having a larger volume than the core part. This is because efficient absorption of excitation light becomes possible and concentration can be decreased.
<<Examination of Influence of Small Bandgap of Shell Part Material>>
In the following, characteristics of a light emitting device using a semiconductor phosphor microparticle having small bandgap energy of shell part will be examined.
Example A1 and Example A19 will be compared. The light emitting devices of Example A1 and Example A19 are fabricated in the same condition except for the shell part material of the red semiconductor phosphor microparticle. The shell part material of the red semiconductor phosphor microparticle is a ZnSe material in Example A1, and is a GaP material in Example A19. It can be seen that luminous efficiency of the light emitting device of Example A1 is 100.0%, while luminous efficiency of the light emitting device of Example A19 significantly decreases to 79.5%.
Example A7 and Example A20 will be compared. The light emitting devices of Example A7 and Example A20 are fabricated in the same condition except for the shell part material of the red semiconductor phosphor microparticle. The shell part material of the red semiconductor phosphor microparticle is a ZnSe material in Example A7, and is a GaP material in Example A20. It can be seen that luminous efficiency of the light emitting device of Example A7 is 47.0%, while luminous efficiency of the light emitting device of Example A20 significantly decreases to 41.7%.
This is attributable to the fact that when the red semiconductor phosphor microparticle whose shell material is a GaP material is used, luminescence of the blue semiconductor phosphor microparticle is absorbed by the GaP shell part of the red phosphor. At this time, due to the loss arising by absorption of the blue luminescence in the red phosphor, luminous efficiency of the light emitting device decreases. That is, from the view point of luminous efficiency of the light emitting device, bandgap energy of the shell part of the semiconductor phosphor microparticle is preferably larger than the bandgap energy of the core part of every semiconductor phosphor microparticle included in the light emitting device.
<<Examination of Difference in Core Part Material>>
In the following, influence of the difference in material of the core part on luminous efficiency of the light emitting device of the present invention will be examined.
FIG. 23 is a chart showing relation of brightness of light emitting devices 1, 41 using semiconductor phosphor microparticles whose shell material is ZnS and ZnSe, respectively. The horizontal axis represents core part material of semiconductor phosphor microparticle, and the vertical axis plots relative value of luminous efficiency of light emitting device. As can be seen from FIG. 23, in every case where the material of the core part is InP, InGaP, InN, InGaN, CdSe, or ZnCdSe, it can be seen that luminous efficiency is higher in the case of using a semiconductor phosphor microparticle of a ZnSe material that absorbs excitation light as the material of the shell part than using a Zns material that allows transmission of excitation light. From the above, it is demonstrated that when the shell part of the semiconductor phosphor microparticle absorbs excitation light, the effect of improving luminous efficiency by suppressing concentration quenching is obtained in the core part material of any semiconductor phosphor microparticle.
<<Examination of Emission Half-Value Width of Semiconductor Phosphor Microparticle>>
In the following, influence of an emission half-value width of the semiconductor phosphor microparticle on color rendering property index Ra value of the light emitting device of the present invention will be examined.
FIG. 24 is a chart plotting Production examples A1, A2, A3 of light emitting device 1 including red and green luminescent two kinds of InP/ZnSe semiconductor phosphor microparticles and a blue semiconductor light emitting diode element, and Production examples E1, E2, E3 of light emitting device 41 including red and green luminescent two kinds of InP/ZnSe semiconductor phosphor microparticles and a blue luminescent organic electroluminescence element. The horizontal axis plots an emission half-value width of InP/ZnSe semiconductor phosphor microparticle, and the vertical axis plots color rendering property index Ra value of light emitting device.
As can been seen from FIG. 24, it is found that as the emission half-value width of semiconductor phosphor microparticle increases, color rendering property index Ra value of the of the light emitting device improves. This is attributable to the fact that the emission spectrum of the light emitting device comes closer to that of the natural white light that is gentle with no peaks and troughs as the emission half-value width of semiconductor phosphor microparticle increases.
<<Number of Phosphor and Ra Value and Luminous Efficiency>>
In the following, influence of the number of the semiconductor phosphor microparticles forming the light emitting device of the present invention on color rendering property index Ra value and luminous efficiency of the light emitting device will be examined.
FIG. 25 and FIG. 26 are charts plotting light emitting devices 1 and 41 including semiconductor phosphor microparticle having an InP core and an InN core, and a blue semiconductor light emitting element or a blue organic electroluminescence element. In FIG. 25, the horizontal axis represents number of phosphors, and the vertical axis represents relative value of luminous efficiency of the light emitting device. In FIG. 26, the horizontal axis represents number of phosphors, and the vertical axis represents color rendering property index Ra value of the light emitting device.
As can be seen from FIG. 25, as the number of kinds of the semiconductor phosphor microparticles increases, luminous efficiency of the light emitting device decreases. This is attributable to the fact that as the number of kinds of the phosphors increases, emission and absorption between phosphors are repeated, so that the energy loss in the phosphors increases. Also in FIG. 26, the tendency that color rendering property index Ra value of the light emitting device increases as the number of kinds of the semiconductor phosphor microparticles increases is also observed. This is attributable to the fact that the emission spectrum of the light emitting device comes closer to that of the natural white light that is gentle with no peaks and troughs as the number of kinds of the phosphor increases.
<<Difference in Characteristics of Light Emitting Device by Difference in Light Source>>
In the following, influence of the kind of light source forming the light emitting device of the present invention on characteristics of the light emitting device will be examined.
Any of the light emitting devices fabricated in Example A1, Example C1, and Example E1 are light emitting devices including a semiconductor phosphor microparticle of Production example 1r, or Production example 1g. Light sources forming the light emitting devices of Example A1, Example C1, and Example E1 differ in that they are a blue semiconductor light emitting diode element, a blue semiconductor light emitting laser diode element, and a blue organic electroluminescence element, respectively. In other words, they correspond to light emitting device 1 in the example shown in FIG. 1, light emitting device 21 in the example shown in FIG. 2, and light emitting device 41 in the example shown in FIG. 3, respectively. Difference in characteristics of the light emitting device by difference in light source was observed.
Light emitting device 1 of Example A1 was excellent in that it had the highest luminous efficiency. This is because the blue semiconductor light emitting diode element having the highest luminous efficiency among other light sources was used. In general, a blue semiconductor light emitting diode element has a feature that a light source having high luminous efficiency can be fabricated more easily compared with other light sources. Therefore, Example A1 is excellent in that a light emitting device having high luminous efficiency can be fabricated.
Light emitting device 21 of Example C1 was excellent in that it had the highest brightness and light output. This is because the blue semiconductor light emitting laser diode element is a point source, and shows the highest light output. Therefore, Example C1 is excellent in that a light emitting device realizing high brightness and light output can be fabricated.
In light emitting device 41 of Example E1, a surface light emitting device could be fabricated. This is because, the organic electroluminescence element is a surface-emitting light emitting element, in contrast to the foregoing semiconductor light emitting element of point luminescence. In other words, Example E1 is excellent in that a surface-emitting light emitting device can be fabricated.
<Fabrication of Image Display Device>
In the following, a method of producing an image display device including a light emitting element, and a semiconductor phosphor microparticle of a core/shell structure having a shell part absorbing at least a part of the light emitted by the light emitting element will be described. In the following examples, for measuring chromaticity point, color reproducibility and brightness of an image display device, a luminescence measuring system MCPD-7000 (available from OTSUKA ELECTRONICS CO. LTD.) was used.
Example AA1
Image Display Device 101)
In Example AA1, image display device 101 having a structure shown in FIG. 5 was fabricated by using light emitting device 1 of Example A1 as a backlight light source, and wavelength conversion part 104 having a color filter having transmissivity shown in FIG. 7. That is, light emitting device 1 described in Example A1 combining a red luminescent semiconductor phosphor microparticle and a green luminescent semiconductor phosphor microparticle that are respectively synthesized in Production examples 1r, 1g, with a blue semiconductor light emitting diode element was used as a backlight. By combining light emitting device 1, with wavelength conversion part 104 including liquid crystal and a color filter, image display device 101 of Example CE1 was fabricated. Image display device 101 fabricated in this method was evaluated, and an NTSC ratio of 105.8% was observed. Brightness of the image display device in the following examples was evaluated as a relative value, relative to brightness of image display device 101 in Example AA1 as 100%.
Examples AA2 to AA28, Comparative Examples AA1 to AA6, Examples AB1 to AB4, Comparative Examples AB1 to AB2, Examples AC1 to AC2, Comparative Examples AC1 to AC2, Examples AD1 to AD4, Comparative Examples AD1 to AD2
Image Display Device 101
Image display device 101 having a structure shown in FIG. 5 including white light emitting device 1 containing various semiconductor phosphor microparticles and a semiconductor light emitting element, and wavelength conversion part 104 having a color filter of transmissivity shown in FIG. 7 will be described.
Image display devices 101 of Examples AA2 to AA28, Comparative examples AA1 to AA6, Examples AB1 to AB4, Comparative examples AB1 to AB2, Examples AC1 to AC2, Comparative examples AC1 to AC2, Examples AD1 to AD4, and Comparative examples AD1 to AD2 were fabricated in a similar manner as Example AA1 except for the light emitting device.
That is, as shown in Table 16, by providing wavelength conversion part 104 having a color filter by using light emitting devices 1 fabricated in Examples A2 to A28, Comparative examples A1 to A6, Examples B1 to B4, Comparative examples B1 to B2, Examples C1 to C2, Comparative examples C1 to C2, Examples D1 to D4, and Comparative examples D1 to D2, image display devices 101 of Examples AA2 to AA28, Comparative examples AA1 to AA6, Examples AB1 to AB4, Comparative examples AB1 to AB2, Examples AC1 to AC2, Comparative examples AC1 to AC2, Examples AD1 to AD4, and Comparative examples AD1 to AD2 were fabricated. Evaluation of image display devices 101 fabricated in the present method revealed NTSC ratios and brightnesses as shown in Table 17.









TABLE 16









Configuration of image display device













Wavelength



Structure of image
Light emitting
conversion


Example
display device
device
part





Example AA1
Image display device 101
Example A1
Color filter


Example AA2
Image display device 101
Example A2
Color filter


Example AA3
Image display device 101
Example A3
Color filter


Example AA4
Image display device 101
Example A4
Color filter


Example AA5
Image display device 101
Example A5
Color filter


Example AA6
Image display device 101
Example A6
Color filter


Example AA7
Image display device 101
Example A7
Color filter


Example AA8
Image display device 101
Example A8
Color filter


Example AA9
Image display device 101
Example A9
Color filter


Example AA10
Image display device 101
Example A10
Color filter


Example AA11
Image display device 101
Example A11
Color filter


Example AA12
Image display device 101
Example A12
Color filter


Example AA13
Image display device 101
Example A13
Color filter


Example AA14
Image display device 101
Example A14
Color filter


Example AA15
Image display device 101
Example A15
Color filter


Example AA16
Image display device 101
Example A16
Color filter


Example AA17
Image display device 101
Example A17
Color filter


Example AA18
Image display device 101
Example A18
Color filter


Example AA19
Image display device 101
Example A19
Color filter


Example AA20
Image display device 101
Example A20
Color filter


Example AA21
Image display device 101
Example A21
Color filter


Example AA22
Image display device 101
Example A22
Color filter


Example AA23
Image display device 101
Example A23
Color filter


Example AA24
Image display device 101
Example A24
Color filter


Example AA25
Image display device 101
Example A25
Color filter


Example AA26
Image display device 101
Example A26
Color filter


Example AA27
Image display device 101
Example A27
Color filter


Example AA28
Image display device 101
Example A28
Color filter


Comparative
Image display device 101
Comparative
Color filter


Example AA1

Example A1


Comparative
Image display device 101
Comparative
Color filter


Example AA2

Example A2


Comparative
Image display device 101
Comparative
Color filter


Example AA3

Example A3


Comparative
Image display device 101
Comparative
Color filter


Example AA4

Example A4


Comparative
Image display device 101
Comparative
Color filter


Example AA5

Example A5


Comparative
Image display device 101
Comparative
Color filter


Example AA6

Example A6


Example AB1
Image display device 101
Example B1
Color filter


Example AB2
Image display device 101
Example B2
Color filter


Example AB3
Image display device 101
Example B3
Color filter


Example AB4
Image display device 101
Example B4
Color filter


Comparative
Image display device 101
Comparative
Color filter


Example AB1

Example B1


Comparative
Image display device 101
Comparative
Color filter


Example AB2

Example B2


Example AC1
Image display device 101
Example C1
Color filter


Example AC2
Image display device 101
Example C2
Color filter


Comparative
Image display device 101
Comparative
Color filter


Example AC1

Example C1


Comparative
Image display device 101
Comparative
Color filter


Example AC2

Example C2


Example AD1
Image display device 101
Example D1
Color filter


Example AD2
Image display device 101
Example D2
Color filter


Example AD3
Image display device 101
Example D3
Color filter


Example AD4
Image display device 101
Example D4
Color filter


Comparative
Image display device 101
Comparative
Color filter


Example AD1

Example D1


Comparative
Image display device 101
Comparative
Color filter


Example AD2

Example D2



















TABLE 17









Structure of luminescent device











Bandgap energy
Characteristics of image display device
















Excitation light
of semiconductor
Red
Green
Blue
White





energy from light
phosphor micro-
chromaticity
chromaticity
chromaticity
chromaticity
NTSC
Bright-



emitting element
particle shell part
point
point
point
point
ratio
ness



















Example
[eV]
[eV]
u′
v′
u′
v′
u′
v′
u′
v′
[%]
[%]






















Example AA1
2.76
2.70
0.5057
0.5179
0.0735
0.5739
0.1589
0.1986
0.1903
0.4399
105.8%
100.0%


Example AA2
2.76
2.70
0.4775
0.5221
0.0925
0.5687
0.1562
0.1993
0.1903
0.4400
93.5%
95.6%


Example AA3
2.76
2.70
0.4589
0.5244
0.1101
0.5663
0.1574
0.1926
0.1903
0.4399
86.2%
94.1%


Example AA4
2.76
2.70
0.5046
0.5180
0.0735
0.5746
0.1603
0.1961
0.1904
0.4399
106.3%
103.2%


Example AA5
2.76
2.70
0.4974
0.5187
0.0832
0.5754
0.1659
0.1832
0.1902
0.4400
106.0%
85.9%


Example AA6
2.76
2.70
0.5170
0.5161
0.0726
0.5735
0.1578
0.2007
0.1902
0.4400
108.0%
79.5%


Example AA7
2.76
2.70
0.5087
0.5170
0.0811
0.5753
0.1644
0.1864
0.1900
0.4402
108.4%
45.9%


Example AA8
2.76
2.70
0.4901
0.5202
0.0895
0.5682
0.1545
0.2025
0.1903
0.4400
96.3%
47.6%


Example AA9
2.76
2.70
0.4647
0.5242
0.1167
0.5636
0.1637
0.1750
0.2112
0.4249
89.6%
41.7%


Example AA10
2.76
2.70
0.5122
0.5166
0.0783
0.5756
0.1646
0.1863
0.1919
0.4388
110.1%
45.0%


Example AA11
2.76
2.70
0.5080
0.5174
0.0765
0.5750
0.1629
0.1897
0.1924
0.4385
108.3%
133.9%


Example AA12
2.76
2.70
0.5032
0.5185
0.0732
0.5729
0.1587
0.1978
0.1943
0.4371
105.2%
111.6%


Example AA13
2.76
2.72
0.5086
0.5178
0.0667
0.5726
0.1561
0.2042
0.1944
0.4370
106.1%
97.6%


Example AA14
2.76
2.72
0.5057
0.5179
0.0748
0.5737
0.1594
0.1973
0.1909
0.4395
105.8%
44.6%


Example AA15
2.76
2.72
0.5107
0.5172
0.0721
0.5728
0.1573
0.2011
0.1922
0.4386
106.3%
22.7%


Example AA16
2.76
2.72
0.5118
0.5164
0.0811
0.5755
0.1644
0.1870
0.1886
0.4412
109.1%
28.3%


Example AA17
2.76
2.72
0.5179
0.5158
0.0745
0.5752
0.1622
0.1919
0.1916
0.4390
110.7%
95.4%


Example AA18
2.76
2.72
0.5135
0.5167
0.0759
0.5735
0.1608
0.1931
0.1945
0.4370
108.6%
46.8%


Example AA19
2.76
2.27
0.5080
0.5172
0.0807
0.5751
0.1649
0.1848
0.1927
0.4382
108.8%
77.7%


Example AA20
2.76
2.27
0.5201
0.5157
0.0690
0.5742
0.1582
0.2006
0.1915
0.4391
109.7%
42.0%


Example AA21
2.76
2.70
0.3727
0.5369
0.2174
0.5592
0.1963
0.0923
0.2464
0.3996
49.0%
110.8%


Example AA22
2.76
2.70
0.3686
0.5366
0.2030
0.5624
0.1955
0.0958
0.2331
0.4092
52.0%
55.6%


Example AA23
2.76
2.70
0.4491
0.5259
0.1267
0.5686
0.1731
0.1582
0.2104
0.4255
87.5%
89.4%


Example AA24
2.76
2.70
0.4540
0.5247
0.1281
0.5703
0.1764
0.1513
0.2068
0.4281
90.2%
42.1%


Example AA25
2.76
2.70
0.5071
0.5189
0.0699
0.5593
0.1369
0.2320
0.1903
0.4400
94.3%
70.1%


Example AA26
2.76
2.70
0.5104
0.5181
0.0777
0.5611
0.1411
0.2214
0.1904
0.4399
96.9%
29.0%


Example AA27
2.76
2.70
0.5047
0.5176
0.0819
0.5751
0.1646
0.1858
0.1903
0.4400
107.4%
66.5%


Example AA28
2.76
2.70
0.4980
0.5189
0.0781
0.5749
0.1626
0.1906
0.1903
0.4399
105.2%
104.5%


Comparative
2.76
3.56
0.5104
0.5168
0.0799
0.5753
0.1642
0.1871
0.1903
0.4400
109.0%
75.1%


Example AA1


Comparative
2.76
3.56
0.5154
0.5164
0.0700
0.5741
0.1579
0.2013
0.1903
0.4400
108.2%
60.6%


Example AA2


Comparative
2.76
3.56
0.4978
0.5193
0.0718
0.5725
0.1561
0.2042
0.1904
0.4399
102.4%
99.7%


Example AA3


Comparative
2.76
3.56
0.5066
0.5180
0.0683
0.5732
0.1558
0.2058
0.1903
0.4400
105.0%
79.3%


Example AA4


Comparative
2.76
3.39
0.5193
0.5160
0.0649
0.5734
0.1548
0.2083
0.1903
0.4399
108.0%
30.0%


Example AA5


Comparative
2.76
3.39
0.5080
0.5175
0.0735
0.5744
0.1599
0.1969
0.1903
0.4399
106.9%
19.2%


Example AA6


Example AB1
3.26
2.70
0.5090
0.5203
0.0633
0.5297
0.1024
0.2835
0.1903
0.4399
73.5%
91.1%


Example AB2
3.26
2.70
0.5128
0.5197
0.0702
0.5315
0.1038
0.2779
0.1903
0.4400
75.2%
35.5%


Example AB3
3.26
2.86
0.5197
0.5188
0.0564
0.5271
0.0992
0.2907
0.1903
0.4399
73.4%
82.4%


Example AB4
3.26
2.86
0.5056
0.5211
0.0658
0.5194
0.0941
0.2961
0.1902
0.4399
66.0%
37.2%


Comparative
3.26
3.56
0.5152
0.5198
0.0568
0.5139
0.0893
0.3061
0.1903
0.4399
64.1%
55.9%


Example AB1


Comparative
3.26
3.39
0.5230
0.5186
0.0523
0.5140
0.0886
0.3079
0.1903
0.4400
65.3%
33.3%


Example AB2


Example AC1
2.76
2.70
0.5058
0.5182
0.0733
0.5767
0.1647
0.1908
0.1904
0.4399
108.5%
52.1%


Example AC2
2.76
2.70
0.5088
0.5173
0.0812
0.5780
0.1708
0.1776
0.1904
0.4399
111.4%
23.6%


Comparative
2.76
3.56
0.5105
0.5171
0.0799
0.5781
0.1704
0.1786
0.1904
0.4399
111.9%
36.8%


Example AC1


Comparative
2.76
3.39
0.5195
0.5163
0.0646
0.5763
0.1602
0.2012
0.1903
0.4400
110.8%
16.1%


Example AC2


Example AD1
3.26
2.70
0.5091
0.5204
0.0619
0.5267
0.0998
0.2881
0.1903
0.4399
71.5%
89.8%


Example AD2
3.26
2.70
0.5128
0.5197
0.0702
0.5315
0.1038
0.2779
0.1903
0.4400
75.2%
35.5%


Example AD3
3.26
2.86
0.5196
0.5187
0.0570
0.5286
0.1005
0.2883
0.1904
0.4399
74.4%
83.0%


Example AD4
3.26
2.86
0.5056
0.5211
0.0658
0.5194
0.0941
0.2961
0.1902
0.4399
66.0%
37.2%


Comparative
3.26
3.56
0.5151
0.5197
0.0585
0.5163
0.0911
0.3024
0.1904
0.4399
65.7%
55.7%


Example AD1


Comparative
3.26
3.39
0.5230
0.5186
0.0523
0.5140
0.0886
0.3079
0.1903
0.4400
65.3%
22.5%


Example AD2









Example BA1
Image Display Device 121
In Example BA1, image display device 121 having a structure shown in FIG. 8 using a blue luminescent semiconductor diode element as light emitting element 122 which is a backlight light source, and including wavelength conversion part 123 using a wavelength conversion member containing semiconductor phosphor microparticles synthesized in Production examples 1r, 1g in place of a color filter will be described.
That is, by sealing and solidifying the red luminescent semiconductor phosphor microparticle and the green luminescent semiconductor phosphor microparticle synthesized in Production examples 1r, 1g in silicone resin, a wavelength conversion member containing the semiconductor phosphor microparticles was fabricated. By using such a wavelength conversion member in place of a color filter, and combining a blue luminescent semiconductor diode element, image display device 121 of Example BA1 was fabricated. Evaluation of image display device 121 fabricated in this method revealed that an NTSC ratio was 129.4%, and brightness was 104.0%.
Examples BA2 to BA12, Comparative examples BA1 to BA8
Image Display Device 121
Image display device 121 having a structure shown in FIG. 8 using a semiconductor light emitting element selected from a blue luminescent semiconductor diode element, a UV luminescent semiconductor diode element, a blue luminescent semiconductor laser diode element, and a UV luminescent semiconductor laser diode element as light emitting element 122 which is a backlight light source, and including wavelength conversion part 123 using a wavelength conversion member containing a semiconductor phosphor microparticle synthesized in Production examples 2r to 22r, 2y to 22y, 2g to 20g, 2b to 20b, and Comparative production examples 1r to 6r, 1y to 6y, 1g to 6g, 1b to 6b in place of a color filter will be described.
Image display devices 121 of Examples BA2 to BA12, and Comparative examples BA1 to BA8 were fabricated in a method similar to that of Example BA1 except for the light emitting device and the semiconductor phosphor microparticle contained in the wavelength conversion member. That is, as shown in Table 18, as a light emitting device, a blue luminescent semiconductor diode element, a UV luminescent semiconductor diode element, a blue luminescent semiconductor laser diode element, or a UV luminescent semiconductor laser diode element were used. Also by sealing and solidifying semiconductor phosphor microparticles synthesized in Production examples 2r to 22r, 2y to 22y, 2g to 20g, 2b to 20b, and Comparative production examples 1r to 6r, 1y to 6y, 1g to 6g, 1b to 6b in silicone resin, wavelength conversion members containing the semiconductor phosphor microparticles were fabricated. Except for this, image display devices 121 of Examples BA2 to BA12, and Comparative examples BA1 to BA8 were fabricated in a method similar to that of Example BA1. Evaluation of image display devices 121 fabricated in this method revealed the NTSC ratios and brightnesses shown in Table 19.









TABLE 18









Configuration of image display device










Example
Structure of image display device
Light emitting device
Wavelength conversion part





Example BA1
Image display device 121
Blue luminescent semiconductor diode
Wavelength conversion member containing production




element
examples 1r, 1g


Example BA2
Image display device 121
Blue luminescent semiconductor diode
Wavelength conversion member containing Production




element
examples 7r, 7g


Example BA3
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Production




diode element
examples 1r, 1g, 1b


Example BA4
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Production




diode element
examples 7r, 7g, 7b


Example BA5
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Production




diode element
examples 19r, 19g, 19b


Example BA6
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Production




diode element
examples 20r, 20g, 20b


Example BA7
Image display device 121
Blue luminescent semiconductor laser
Wavelength conversion member containing Production




diode element
examples 1r, 1g


Example BA8
Image display device 121
Blue luminescent semiconductor laser
Wavelength conversion member containing Production




diode element
examples 7r, 7g


Example BA9
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Production




laser diode element
examples 1r, 1g, 1b


Example BA10
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Production




laser diode element
examples 7r, 7g, 7b


Example BA11
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Production




laser diode element
examples 19r, 19g, 19b


Example BA12
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Production




laser diode element
examples 20r, 20g, 20b


Comparative
Image display device 121
Blue luminescent semiconductor diode
Wavelength conversion member containing Production


Example BA1

element
examples 1r, 1g


Comparative
Image display device 121
Blue luminescent semiconductor diode
Wavelength conversion member containing Production


Example BA2

element
examples 5r, 5g


Comparative
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Comparative


Example BA3

diode element
production examples 1r, 1g, 1b


Comparative
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Comparative


Example BA4

diode element
production examples 5r, 5g, 5b


Comparative
Image display device 121
Blue luminescent semiconductor laser
Wavelength conversion member containing Comparative


Example BA5

diode element
production examples 1r, 1g


Comparative
Image display device 121
Blue luminescent semiconductor laser
Wavelength conversion member containing Comparative


Example BA6

diode element
production examples 5r, 5g


Comparative
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Comparative


Example BA7

laser diode element
production examples 1r, 1g, 1b


Comparative
Image display device 121
Blue-violet luminescent semiconductor
Wavelength conversion member containing Comparative


Example BA8

laser diode element
production examples 5r, 5g, 5b



















TABLE 19









Structure of luminescent device











Bandgap energy
Characteristics of image display device
















Excitation light
of semiconductor
Red
Green
Blue
White





energy from light
phosphor micro-
chromaticity
chromaticity
chromaticity
chromaticity
NTSC
Bright-



emitting element
particle shell part
point
point
point
point
ratio
ness



















Example
[eV]
[eV]
u′
v′
u′
v′
u′
v′
u′
v′
[%]
[%]






















Example BA1
2.76
2.70
0.4995
0.5168
0.0658
0.5764
0.1971
0.0929
0.1903
0.4399
129.4%
104.0%


Example BA2
2.76
2.70
0.5059
0.5269
0.0767
0.5867
0.1978
0.0918
0.1903
0.4400
131.5%
48.1%


Example BA3
3.26
2.70
0.5063
0.5214
0.0666
0.5739
0.1027
0.2700
0.1903
0.4400
84.4%
90.6%


Example BA4
3.26
2.70
0.5006
0.5175
0.0764
0.5837
0.1030
0.2658
0.1903
0.4400
85.3%
35.7%


Example BA5
3.26
2.86
0.5134
0.5291
0.0570
0.5837
0.1001
0.2750
0.1904
0.4399
88.8%
81.7%


Example BA6
3.26
2.86
0.5026
0.5296
0.0799
0.5718
0.0895
0.3028
0.1903
0.4399
72.6%
36.5%


Example BA7
2.76
2.70
0.5164
0.5182
0.0662
0.5811
0.2074
0.0749
0.1903
0.4400
140.4%
54.1%


Example BA8
2.76
2.70
0.5137
0.5246
0.0776
0.5767
0.2043
0.0749
0.1903
0.4400
136.0%
24.8%


Example BA9
3.26
2.70
0.5117
0.5275
0.0673
0.5817
0.1033
0.2696
0.1903
0.4400
87.7%
90.5%


Example BA10
3.26
2.70
0.5042
0.5103
0.0766
0.5914
0.1012
0.2699
0.1903
0.4399
86.8%
35.7%


Example BA11
3.26
2.86
0.5157
0.5282
0.0572
0.5774
0.1013
0.2740
0.1903
0.4399
87.7%
81.7%


Example BA12
3.26
2.86
0.4995
0.5285
0.0805
0.5824
0.0898
0.3048
0.1904
0.4399
74.2%
36.5%


Comparative
2.76
3.56
0.5193
0.5172
0.0754
0.5751
0.2000
0.0931
0.1903
0.4400
132.5%
74.0%


Example BA1


Comparative
2.76
3.39
0.5305
0.5255
0.0585
0.5868
0.2013
0.0921
0.1903
0.4400
144.0%
32.4%


Example BA2


Comparative
3.26
3.56
0.5161
0.5247
0.0760
0.5812
0.0837
0.3184
0.1903
0.4399
73.9%
55.7%


Example BA3


Comparative
3.26
3.39
0.5347
0.5170
0.0764
0.5857
0.0858
0.3060
0.1904
0.4399
81.8%
22.3%


Example BA4


Comparative
2.76
3.56
0.5169
0.5118
0.0763
0.5824
0.2094
0.0748
0.1903
0.4400
137.3%
39.1%


Example BA5


Comparative
2.76
3.39
0.5383
0.5334
0.0588
0.5953
0.2072
0.0744
0.1903
0.4399
154.2%
16.7%


Example BA6


Comparative
3.26
3.56
0.5121
0.5171
0.0766
0.5763
0.0838
0.3231
0.1903
0.4399
70.4%
56.3%


Example BA7


Comparative
3.26
3.39
0.5269
0.5206
0.0774
0.5758
0.0852
0.3050
0.1904
0.4399
77.7%
22.0%


Example BA8









Example CE1
Image Display Device 151
In Example CE1, by using light emitting device 41 of Example E1 as a backlight light source, and using wavelength conversion part 104 having a color filter of the transmissivity shown in FIG. 7, image display device 151 having a structure shown in FIG. 11 was fabricated. That is, light emitting device 41 of Example E1 in which a red luminescent semiconductor phosphor microparticle and a green luminescent semiconductor phosphor microparticle respectively synthesized in Production examples 1r and 1g were combined with a blue luminescent organic electroluminescence element, was used as a backlight. By combining such light emitting device 41 with wavelength conversion part 104 including liquid crystal and a color filter, image display device 151 of Example CE1 was fabricated. Image display device 151 fabricated in the present method was evaluated, to reveal that an NTSC ratio was 99.4% and brightness was 64.1%.
Examples CE2 to CE4, Comparative Examples CE1 to CE2
Image Display Device 151
Image display device 151 having a structure shown in FIG. 11 including white light emitting device 41 made up of various semiconductor phosphor microparticles and a blue luminescent organic electroluminescence element, and wavelength conversion part 104 having a color filter of the transmissivity shown in FIG. 7 will be described.
Except for the light emitting device, image display devices 151 of Examples CE2 to CE4, and Comparative examples CE1 to CE2 were fabricated in a method similar to that of Example CE1. That is, as shown in Table 20, by using light emitting devices fabricated in Examples E2 to A27, and Comparative examples E1 to E6 as a backlight light source, and including wavelength conversion part 104 having a color filter, image display devices 151 of Examples CE2 to CE4, and Comparative example CE1 to CE2 were fabricated. Evaluation of image display devices 151 fabricated in the present method revealed the NTSC ratios and brightnesses shown in Table 21.









TABLE 20









Configuration of image display device













Wavelength



Structure of image
Light emitting
conversion


Example
display device
device
part





Example CE1
Image display device 151
Example E1
Color filter


Example CE2
Image display device 151
Example E7
Color filter


Example CE3
Image display device 151
Example E21
Color filter


Example CE4
Image display device 151
Example E23
Color filter


Comparative
Image display device 151
Comparative
Color filter


Example CE1

Example E1


Comparative
Image display device 151
Comparative
Color filter


Example CE2

Example E5



















TABLE 21









Structure of luminescent device











Bandgap energy
Characteristics of image display device
















Excitation light
of semiconductor
Red
Green
Blue
White





energy from light
phosphor micro-
chromaticity
chromaticity
chromaticity
chromaticity
NTSC
Bright-



emitting element
particle shell part
point
point
point
point
ratio
ness



















Example
[eV]
[eV]
u′
v′
u′
v′
u′
v′
u′
v′
[%]
[%]






















Example CE1
2.73
2.70
0.5056
0.5175
0.0716
0.5662
0.1478
0.2167
0.1903
0.4400
99.4%
64.1%


Example CE2
2.73
2.70
0.5089
0.5166
0.0783
0.5676
0.1521
0.2069
0.1903
0.4399
101.8%
30.4%


Example CE3
2.73
2.70
0.3722
0.5362
0.1948
0.5531
0.1751
0.1361
0.2263
0.4140
49.9%
75.1%


Example CE4
2.73
2.70
0.4415
0.5261
0.1175
0.5632
0.1548
0.1962
0.1904
0.4399
78.9%
61.9%


Comparative
2.73
3.56
0.5105
0.5164
0.0771
0.5677
0.1518
0.2077
0.1903
0.4399
102.2%
46.9%


Example CE1


Comparative
2.73
3.39
0.5191
0.5156
0.0636
0.5657
0.1445
0.2248
0.1903
0.4399
101.6%
20.9%


Example CE2









Example DE1
Image Display Device 161
In Example DE1, image display device 161 having a structure shown in FIG. 12 using a blue luminescent organic electroluminescence element as a backlight light source, and including wavelength conversion part 123 using a wavelength conversion member containing semiconductor phosphor microparticles synthesized in Production examples 1r, 1g in place of a color filter will be described. That is, by sealing and solidifying the red luminescent semiconductor phosphor microparticle and the green luminescent semiconductor phosphor microparticle respectively synthesized in Production examples 1r, 1g in silicone resin, a wavelength conversion member containing semiconductor phosphor microparticles was fabricated. By combining wavelength conversion part 123 using such a wavelength conversion member in place of a color filter, with light emitting element 162 using a blue luminescent organic electroluminescence element, image display device 161 of Example DE1 was fabricated. Image display device 161 fabricated in the present method was evaluated, to reveal that an NTSC ratio was 117.3%, and brightness was 66.4%.
Example DE2, Comparative Examples DE1 to DE2
Image Display Device 161
Image display device 161 having a structure shown in FIG. 12 using a blue luminescent organic electroluminescence element as light emitting element 162 which is a backlight light source, and including wavelength conversion part 123 using a wavelength conversion member containing semiconductor phosphor microparticles synthesized in Production examples 2r to 22r, 2y to 22y, 2g to 20g, 2b to 20b, and Comparative production examples 1r to 6r, 1y to 6y, 1g to 6g, 1b to 6b in place of a color filter will be described.
Image display devices 161 of Example DE2, and Comparative examples DE1 to DE2 were fabricated by using a method similar to that of Example DE1 except for the light emitting device and semiconductor phosphor microparticles contained in the wavelength conversion member. That is, as shown in Table 22, as the light emitting device, a blue luminescent organic electroluminescence element was used. Further, by sealing and solidifying semiconductor phosphor microparticles synthesized in Production examples 2r to 22r, 2y to 22y, 2g to 20g, 2b to 20b, and Comparative production examples 1r to 6r, 1y to 6y, 1g to 6g, 1b to 6b in silicone resin, a wavelength conversion member containing semiconductor phosphor microparticles was fabricated. Except for this, in a method similar to that of Example DE1, image display devices 161 of Example DE2 and Comparative examples DE1 to DE2 were fabricated. Evaluation of image display devices 161 fabricated in the present method revealed an NTSC ratio and brightness as shown in Table 23.









TABLE 22









Configuration of image display device










Example
Structure of image display device
Light emitting device
Wavelength conversion part





Example DE1
Image display device 161
Blue organic EL element
Wavelength conversion member containing Production





examples 1r, 1g


Example DE2
Image display device 161
Blue organic EL element
Wavelength conversion member containing Production





examples 7r, 7g


Comparative
Image display device 161
Blue organic EL element
Wavelength conversion member containing Comparative


Example DE1


production examples 1r, 1g


Comparative
Image display device 161
Blue organic EL element
Wavelength conversion member containing Comparative


Example DE2


production examples 5r, 5g



















TABLE 23









Structure of luminescent device











Bandgap energy
Characteristics of image display device
















Excitation light
of semiconductor
Red
Green
Blue
White





energy from light
phosphor micro-
chromaticity
chromaticity
chromaticity
chromaticity
NTSC
Bright-



emitting element
particle shell part
point
point
point
point
ratio
ness



















Example
[eV]
[eV]
u′
v′
u′
v′
u′
v′
u′
v′
[%]
[%]






















Example DE1
2.73
2.70
0.5071
0.5239
0.0663
0.5793
0.1753
0.1530
0.1904
0.4399
117.3%
66.4%


Example DE2
2.73
2.70
0.5125
0.5231
0.0772
0.5807
0.1753
0.1530
0.1903
0.4399
117.5%
31.7%


Comparative
2.73
3.56
0.5148
0.5227
0.0760
0.5807
0.1753
0.1530
0.1903
0.4399
117.4%
47.2%


Example DE1


Comparative
2.73
3.39
0.5232
0.5215
0.0580
0.5785
0.1753
0.1530
0.1903
0.4400
120.5%
20.1%


Example DE2









Example EE1
Image Display Device 171
In Example EE1, image display device 171 having a structure shown in FIG. 13 was fabricated by using light emitting device 41 of Example E1 as a backlight light source, and using wavelength conversion part 172 having a color filter of the transmissivity shown in FIG. 7. That is, light emitting device 41 described in Example E1 combining the red luminescent semiconductor phosphor microparticle and the green luminescent semiconductor phosphor microparticle synthesized in Production examples 1r, 1g, with a blue luminescent organic electroluminescence element was used as a backlight. By combining light emitting device 41 with wavelength conversion part 172 made up of liquid crystal and a color filter, image display device 171 of Example CE1 was fabricated. Image display device 171 fabricated in the present method was evaluated, to reveal that an NTSC ratio was 98.7%, and brightness was 63.9%.
Example EE2, Comparative Examples EE1 to EE2
Image Display Device 171
Image display device 171 having a structure shown in FIG. 13 including white light emitting device 41 made up of various semiconductor phosphor microparticles and a blue luminescent organic electroluminescence element, and wavelength conversion part 172 having a color filter of the transmissivity shown in FIG. 7 will be described.
Using a method similar to that of Example EE1 except for the light emitting device, image display devices 171 of Example EE, and Comparative examples EE1 to EE2 were fabricated. That is, as shown in Table 24, image display devices 171 of Examples CE2 to CE4, and Comparative examples CE1 to CE2 were fabricated by using light emitting devices fabricated in Examples E2 to A27, and Comparative examples E1 to E6 as a backlight light source, and providing wavelength conversion part 172 having a color filter. Evaluation of image display devices 171 fabricated in the present method revealed an NTSC ratio and brightness as shown in Table 25.









TABLE 24









Configuration of image display device













Wavelength



Structure of image
Light emitting
conversion


Example
display device
device
part





Example EE1
Image display device 171
Example E1
Color filter


Example EE2
Image display device 171
Example E7
Color filter


Comparative
Image display device 171
Comparative
Color filter


Example EE1

Example E1


Comparative
Image display device 171
Comparative
Color filter


Example EE2

Example E5



















TABLE 25









Structure of luminescent device











Bandgap energy
Characteristics of image display device
















Excitation light
of semiconductor
Red
Green
Blue
White





energy from light
phosphor micro-
chromaticity
chromaticity
chromaticity
chromaticity
NTSC
Bright-



emitting element
particle shell part
point
point
point
point
ratio
ness



















Example
[eV]
[eV]
u′
v′
u′
v′
u′
v′
u′
v′
[%]
[%]






















Example EE1
2.73
2.70
0.5094
0.5148
0.0719
0.5670
0.1486
0.2177
0.1884
0.4365
98.7%
63.9%


Example EE2
2.73
2.70
0.5090
0.5188
0.0781
0.5717
0.1510
0.2069
0.1902
0.4431
102.6%
30.2%


Comparative
2.73
3.56
0.5075
0.5145
0.0775
0.5727
0.1517
0.2082
0.1889
0.4384
102.7%
45.7%


Example EE1


Comparative
2.73
3.39
0.5143
0.5167
0.0637
0.5696
0.1455
0.2269
0.1909
0.4437
101.9%
20.6%


Example EE1









Example FE1
Image Display Device 181
In Example FE1, image display device 181 having a structure shown in FIG. 15 using a blue luminescent organic electroluminescence element as light emitting element 162 which is a backlight light source, and including wavelength conversion part 182 using a wavelength conversion member containing semiconductor phosphor microparticles synthesized in Production examples 1r, 1g in place of a color filter will be described.
That is, by sealing and solidifying the red luminescent semiconductor phosphor microparticle and the green luminescent semiconductor phosphor microparticle, respectively synthesized in Production examples 1r, 1g in a silicone resin, wavelength conversion member 186 containing semiconductor phosphor microparticles was fabricated. By combining wavelength conversion member 186 with a blue luminescent organic electroluminescence element, image display device 181 of Example FE1 was fabricated. Image display device 181 fabricated in the present method was evaluated, to reveal that an NTSC ratio was 117.3% and brightness was 66.4%.
Examples FE2 to FE24, Comparative Examples FE1 to FE2
Image Display Device 181
Image display device 181 having a structure shown in FIG. 15 using a blue luminescent organic electroluminescence element as light emitting element 162 which is a backlight light source, and wavelength conversion part 182 using a wavelength conversion member containing semiconductor phosphor microparticles synthesized in Production examples 2r to 22r, 2y to 22y, 2g to 20g, 2b to 20b, and Comparative production examples 1r to 6r, 1y to 6y, 1g to 6g, 1b to 6b in place of a color filter will be described.
Image display devices 181 of Examples FE2 to FE24, and Comparative example FE1 to FE2 were fabricated in a similar manner as that of Example FE1 except for the light emitting device and semiconductor phosphor microparticles contained in the wavelength conversion member. That is, as shown in Table 26, as light emitting element 162, a blue luminescent organic electroluminescence element was used. By sealing and solidifying semiconductor phosphor microparticles synthesized in Production examples 2r to 22r, 2y to 22y, 2g to 20g, 2b to 20b, and Comparative production examples it to 6r, 1y to 6y, 1g to 6g, 1b to 6b in silicone resin, a wavelength conversion member containing semiconductor phosphor microparticles were fabricated. Except for this, image display devices 181 of Examples FE2 to FE24, and Comparative examples FE1 to FE2 were fabricated in a manner similar to that of Example FE1. Evaluation of image display devices 181 fabricated in the present method revealed an NTSC ratio and brightness as shown in Table 27.









TABLE 26









Configuration of image display device










Example
Structure of image display device
Light emitting device
Wavelength conversion part





Example FE1
Image display device 181
Example E1
Wavelength conversion member containing Production





examples 1r, 1g


Example FE2
Image display device 181
Example E2
Wavelength conversion member containing Production





examples 2r, 2g


Example FE3
Image display device 181
Example E3
Wavelength conversion member containing Production





examples 3r, 3g


Example FE4
Image display device 181
Example E4
Wavelength conversion member containing Production





examples 4r, 4g


Example FE5
Image display device 181
Example E5
Wavelength conversion member containing Production





examples 5r, 5g


Example FE6
Image display device 181
Example E6
Wavelength conversion member containing Production





examples 6r, 6g


Example FE7
Image display device 181
Example E7
Wavelength conversion member containing Production





examples 7r, 7g


Example FE8
Image display device 181
Example E8
Wavelength conversion member containing Production





examples 8r, 8g


Example FE9
Image display device 181
Example E9
Wavelength conversion member containing Production





examples 9r, 9g


Example FE10
Image display device 181
Example E10
Wavelength conversion member containing Production





examples 10r, 10g


Example FE11
Image display device 181
Example E11
Wavelength conversion member containing Production





examples 11r, 11g


Example FE12
Image display device 181
Example E12
Wavelength conversion member containing Production





examples 12r, 12g


Example FE13
Image display device 181
Example E13
Wavelength conversion member containing Production





examples 13r, 13g


Example FE14
Image display device 181
Example E14
Wavelength conversion member containing Production





examples 14r, 14g


Example FE15
Image display device 181
Example E15
Wavelength conversion member containing Production





examples 15r, 15g


Example FE16
Image display device 181
Example E16
Wavelength conversion member containing Production





examples 16r, 16g


Example FE17
Image display device 181
Example E17
Wavelength conversion member containing Production





examples 17r, 17g


Example FE18
Image display device 181
Example E18
Wavelength conversion member containing Production





examples 18r, 18g


Example FE19
Image display device 181
Example E19
Wavelength conversion member containing Production





examples 21r, 21g


Example FE20
Image display device 181
Example E20
Wavelength conversion member containing Production





examples 22r, 22g


Example FE21
Image display device 181
Example E25
Wavelength conversion member containing Production





examples 1r, 1g, 1b


Example FE22
Image display device 181
Example E26
Wavelength conversion member containing Production





examples 7r, 7g, 7b


Example FE23
Image display device 181
Example E27
Wavelength conversion member containing Production





examples 1r, 7g


Example FE24
Image display device 181
Example E28
Wavelength conversion member containing Production





examples 5r, 11g


Comparative
Image display device 181
Comparative
Comparative Wavelength conversion member containing


Example FE1

Example E1
Comparative production examples 1r, 1g


Comparative
Image display device 181
Comparative
Comparative Wavelength conversion member containing


Example FE2

Example E2
Comparative production examples 2r, 2g


Comparative
Image display device 181
Comparative
Comparative Wavelength conversion member containing


Example FE3

Example E3
Comparative production examples 3r, 3g


Comparative
Image display device 181
Comparative
Comparative Wavelength conversion member containing


Example FE4

Example E4
Comparative production examples 4r, 4g


Comparative
Image display device 181
Comparative
Comparative Wavelength conversion member containing


Example FE5

Example E5
Comparative production examples 5r, 5g


Comparative
Image display device 181
Comparative
Wavelength conversion member containing Comparative


Example FE6

Example E6
production examples 6r, 6g



















TABLE 27









Structure of luminescent device











Bandgap energy
Characteristics of image display device
















Excitation light
of semiconductor
Red
Green
Blue
White





energy from light
phosphor micro-
chromaticity
chromaticity
chromaticity
chromaticity
NTSC
Bright-



emitting element
particle shell part
point
point
point
point
ratio
ness



















Example
[eV]
[eV]
u′
v′
u′
v′
u′
v′
u′
v′
[%]
[%]






















Example FE1
2.73
2.70
0.5103
0.5251
0.0657
0.5762
0.1758
0.1518
0.1904
0.4399
117.3%
66.4%


Example FE2
2.73
2.70
0.4478
0.5347
0.0805
0.5705
0.1750
0.1527
0.1904
0.4399
96.2%
65.4%


Example FE3
2.73
2.70
0.4001
0.5450
0.1103
0.5536
0.1749
0.1533
0.1903
0.4400
74.0%
66.0%


Example FE4
2.73
2.70
0.5059
0.5228
0.0663
0.5822
0.1763
0.1525
0.1903
0.4399
116.9%
68.5%


Example FE5
2.73
2.70
0.5025
0.5239
0.0774
0.5803
0.1736
0.1540
0.1903
0.4399
112.7%
58.3%


Example FE6
2.73
2.70
0.5194
0.5174
0.0676
0.5782
0.1766
0.1527
0.1903
0.4400
119.0%
53.2%


Example FE7
2.73
2.70
0.5176
0.5275
0.0773
0.5819
0.1750
0.1536
0.1903
0.4399
117.5%
31.7%


Example FE8
2.73
2.70
0.4731
0.5241
0.0844
0.5673
0.1742
0.1530
0.1903
0.4399
100.7%
33.4%


Example FE9
2.73
2.70
0.3986
0.5383
0.1079
0.5509
0.1752
0.1518
0.1903
0.4400
73.8%
31.8%


Example FE10
2.73
2.70
0.5123
0.5278
0.0730
0.5816
0.1768
0.1523
0.1903
0.4399
117.3%
31.2%


Example FE11
2.73
2.70
0.5135
0.5227
0.0698
0.5807
0.1770
0.1524
0.1903
0.4399
117.8%
88.4%


Example FE12
2.73
2.70
0.5041
0.5282
0.0646
0.5755
0.1746
0.1536
0.1903
0.4399
115.5%
74.7%


Example FE13
2.73
2.72
0.5117
0.5255
0.0570
0.5838
0.1755
0.1539
0.1903
0.4399
120.9%
65.1%


Example FE14
2.73
2.72
0.5034
0.5234
0.0682
0.5782
0.1738
0.1528
0.1903
0.4399
114.9%
30.6%


Example FE15
2.73
2.72
0.5175
0.5245
0.0660
0.5770
0.1764
0.1524
0.1903
0.4399
119.1%
15.8%


Example FE16
2.73
2.72
0.5194
0.5248
0.0775
0.5768
0.1741
0.1526
0.1903
0.4399
116.9%
19.7%


Example FE17
2.73
2.72
0.5253
0.5236
0.0699
0.5818
0.1763
0.1541
0.1903
0.4400
120.9%
63.9%


Example FE18
2.73
2.72
0.5222
0.5219
0.0714
0.5815
0.1740
0.1544
0.1903
0.4400
119.5%
32.6%


Example FE19
2.73
2.27
0.5106
0.5264
0.0762
0.5845
0.1763
0.1521
0.1904
0.4399
116.6%
52.7%


Example FE20
2.73
2.27
0.5281
0.5196
0.0634
0.5773
0.1748
0.1538
0.1903
0.4399
122.0%
28.4%


Example FE21
2.73
2.70
0.5106
0.5261
0.0665
0.5793
0.1046
0.2721
0.1903
0.4399
86.5%
49.9%


Example FE22
2.73
2.70
0.5053
0.5161
0.0763
0.5873
0.1022
0.2672
0.1903
0.4400
86.8%
21.8%


Example FE23
2.73
2.70
0.5030
0.5249
0.0767
0.5762
0.1763
0.1541
0.1903
0.4400
112.1%
46.2%


Example FE24
2.73
2.70
0.5007
0.5204
0.0700
0.5848
0.1753
0.1527
0.1903
0.4399
114.9%
69.1%


Comparative
2.73
3.56
0.5104
0.5242
0.0659
0.5801
0.1752
0.1541
0.1903
0.4399
117.4%
50.3%


Example FE1


Comparative
2.73
3.56
0.5185
0.5182
0.0805
0.5733
0.1765
0.1529
0.1903
0.4399
114.6%
39.9%


Example FE2


Comparative
2.73
3.56
0.4966
0.5232
0.1098
0.5614
0.1758
0.1531
0.1904
0.4399
99.6%
66.1%


Example FE3


Comparative
2.73
3.56
0.5084
0.5267
0.0660
0.5856
0.1767
0.1519
0.1903
0.4399
118.8%
51.9%


Example FE4


Comparative
2.73
3.39
0.5277
0.5202
0.0771
0.5835
0.1754
0.1526
0.1903
0.4400
120.5%
20.1%


Example FE5


Comparative
2.73
3.39
0.5087
0.5244
0.0679
0.5836
0.1761
0.1538
0.1904
0.4399
117.3%
12.9%


Example FE6









<<Examination of Difference Depending on Bandgap of Shell Part Material>>

In the following, influence of difference in material of the shell part of the semiconductor phosphor microparticle on brightness of the image display device of the present invention will be examined.
FIG. 27, FIG. 28 and FIG. 29 are graphs showing relation of brightness of image display devices 101, 181 using various semiconductor phosphor microparticles having a core/shell structure. In FIG. 27 to FIG. 29, the horizontal axis represents bandgap energy of the shell part material of the semiconductor phosphor microparticle, and the vertical axis plots a relative value of brightness of the image display device. Here, as an excitation light source of the image display device, a light emitting device including a blue semiconductor light emitting diode element and a blue semiconductor light emitting laser diode element is used in FIG. 27, and a light emitting device including a UV semiconductor light emitting diode element and a UV semiconductor light emitting laser diode element is used in FIG. 28, and a light emitting device including a blue electroluminescence element is used in FIG. 29. The straight line in the drawing represents energy of excitation light emitted from the light source. In every case of FIG. 27 to FIG. 29, it can be found that brightness of the image display device increases when bandgap energy of the shell part material is smaller than excitation light energy of the light source. This is attributable to the fact that concentration quenching of semiconductor phosphor microparticle can be suppressed by absorbing excitation light in the shell part having larger volume than the core part. This is because concentration can be decreased by the capability of efficient absorption of excitation light.
<<Examination of Influence when Bandgap of Shell Part Material is Small>>
In the following, characteristics of an image display device using a semiconductor phosphor microparticle having small bandgap energy of the shell part will be examined.
Example AA1 and Example AA19 will be compared. Image display devices of Example AA1 and Example AA19 were fabricated in the same condition except for the shell part material of the red semiconductor phosphor microparticle. As the shell part material of the red semiconductor phosphor microparticle, a ZnSe material was used in Example AA1, and a GaP material was used in Example AA19. At this time, it can be found that brightness of the image display device of AA19 significantly decreases to 77.7%, in contrast to the brightness of the image display device of Example A1 of 100.0%.
Example AA7 and Example AA20 will be compared. Image display devices of Example AA7 and Example AA20 were fabricated in the same condition except for the shell part material of the red semiconductor phosphor microparticle. As the shell part material of the red semiconductor phosphor microparticle, a ZnSe material was used in Example A1, and a GaP material was used in Example AA19. At this time, it can be found that brightness of the image display device of A20 significantly decreases to 42.0%, in contrast to the brightness of the image display device of Example AA7 of 45.9%.
This is attributable to the fact that when the red semiconductor phosphor microparticle in which the shell part material is a GaP material is used, the red phosphor absorbs luminescence of a blue semiconductor phosphor microparticle. At this time, brightness of the image display device decreases due to the loss arising by absorption of the blue luminescence in the red phosphor. That is, from the view point of brightness of the image display device, it is preferred that bandgap energy of the shell part of the semiconductor phosphor microparticle is larger than bandgap energy of the core part of any semiconductor phosphor microparticles contained in the image display device.
<<Examination of Difference in Core Part Material>>
In the following, influence of the difference in material of the core part on brightness of the image display device of the present invention will be examined.
FIG. 30 is a graph showing relation of brightness of image display device 101 and image display device 181 using a semiconductor phosphor microparticle whose shell part material is ZnS and ZnSe. The horizontal axis plots core part material of semiconductor phosphor microparticle, and the vertical axis plots relative value of brightness of image display device. As can be seen from FIG. 30, it is demonstrated that luminous efficiency is higher when ZnSe is used than ZnS is used as a material of the shell part in every case where the material of core part is InP, GaInP, InN, GaInN, CdSe, and ZnCdSe. It can be found that when the shell part of semiconductor phosphor microparticle absorbs excitation light, concentration quenching is suppressed and brightness of the image display device increases regardless of the core part material of the semiconductor phosphor microparticle.
<<Examination of Emission Half-Value Width of Semiconductor Phosphor Microparticle>>
In the following, influence of an emission half-value width of a semiconductor phosphor microparticle on an NTSC ratio of the image display device of the present invention will be examined.
FIG. 31 is a graph plotting characteristics of image display device 101 including red and green luminescent two kinds of InP/ZnSe semiconductor phosphor microparticles and a blue semiconductor light emitting diode element, and image display device 181 including red and green luminescent two kinds of InP/ZnSe semiconductor phosphor microparticles, and a blue luminescent organic electroluminescence element. The horizontal axis plots an emission half-value width of InP/ZnSe semiconductor phosphor microparticle, and the vertical axis plots an NTSC ratio of image display device.
As seen in FIG. 31, it can be found that as the emission half-value width of the semiconductor phosphor microparticle increases, the NTSC ratio of the image display device decreases. This is attributable to the fact that color purity of each chromaticity point of red, green and blue of the image display device decreases as the emission half-value width of the semiconductor phosphor microparticle increases.
<<Examination of Number of Phosphors>>
In the following, influence of the number of semiconductor phosphor microparticle forming the light emitting device of the present invention on an NTSC ratio of the image display device will be examined.
FIG. 32 is a chart plotting characteristics of image display devices 101, 181 including a semiconductor phosphor microparticle having an InP core and an InN core, and a blue semiconductor light emitting element and a blue organic electroluminescence element. In FIG. 32, the horizontal axis represents number of phosphors, and vertical axis represents an NTSC ratio of image display device of light emitting device.
As can been seen from FIG. 32, the tendency that an NTSC ratio of image display device increases as the number of kinds of semiconductor phosphor microparticles increases. This is attributable to the fact that color purity of each chromaticity point of red, green and blue of the image display device increases as the number of kinds of phosphor increases.
While description has been made for the examples of the present invention, it is essentially contemplated that configurations of the above-described examples are appropriately combined.
Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the scope of the present invention being interpreted by the terms of the appended claims.

## Claims

1. A light emitting device comprising:
a light emitting element, and
a semiconductor phosphor microparticle having a core/shell structure having a core part and a shell part that covers the core part and absorbs at least a part of the light emitted by the light emitting element,
wherein the shell part of the semiconductor phosphor microparticle is ZnSe or SiC.

2. The light emitting device according to claim 1, wherein bandgap energy of the shell part of the semiconductor phosphor microparticle is smaller than light energy emitted from the light emitting element.

3. The light emitting device according to claim 1, wherein bandgap energy of the shell part of the semiconductor phosphor microparticle is larger than bandgap energy of the core part.

4. The light emitting device according to claim 1, including two or more kinds of semiconductor phosphor microparticles having different peak wavelengths of an emission spectrum.

5. The light emitting device according to claim 4, wherein bandgap energy of the shell part of the semiconductor phosphor microparticle is larger than bandgap energy of the core part of any of the semiconductor phosphor microparticles.

6. The light emitting device according to claim 1, wherein a half-value width of an emission spectrum of the core part of the semiconductor phosphor microparticle is 80 nm or more.

7. The light emitting device according to claim 1, wherein standard deviation of particle diameter distribution of the core part of the semiconductor phosphor microparticle is 20% or more of mean particle diameter of the core part of the semiconductor phosphor microparticle.

8. The light emitting device according to claim 1, wherein the core part of the semiconductor phosphor microparticle is a group II-VI semiconductor material or a group III-V semiconductor material.

9. The light emitting device according to claim 8, wherein the core part of the semiconductor phosphor microparticle is formed of ternary or higher mixed crystal.

10. The light emitting device according to claim 8, wherein the core part of the semiconductor phosphor microparticle is either of InP, InGaP, InN, and InGaN.

11. The light emitting device according to claim 1, wherein the semiconductor phosphor microparticle has a plurality of shell parts.

12. The light emitting device according to claim 1, wherein the semiconductor phosphor microparticle is covered with a translucent member.

13. The light emitting device according to claim 1, wherein the light emitting element is a semiconductor light emitting diode element or a semiconductor laser diode element.

14. The light emitting device according to claim 13, wherein the semiconductor light emitting diode element or the semiconductor laser diode element is formed of a GaN-based material.

15. The light emitting device according to claim 1, wherein the light emitting element is an organic electroluminescence element.

16. The light emitting device according to claim 13, wherein an emission spectrum of the light emitting element has a peak wavelength in the range of 420 to 480 nm.

17. The light emitting device according to claim 13, wherein an emission spectrum of the light emitting element has a peak wavelength in the range of 350 to 420 nm.

18. The light emitting device according to claim 1, including a blue luminescent light emitting element, and a red luminescent semiconductor phosphor microparticle and a green luminescent semiconductor phosphor microparticle.

19. The light emitting device according to claim 1, including a UV to blue-violet luminescent light emitting element, a blue luminescent semiconductor phosphor microparticle, a green luminescent semiconductor phosphor microparticle and a red luminescent semiconductor phosphor microparticle.

20. An image display device comprising:
a light emitting element, and
a semiconductor phosphor microparticle having a core/shell structure having a core part and a shell part that covers the core part and absorbs at least a part of light emitted by the light emitting element,
wherein the shell part of the semiconductor phosphor microparticle is ZnSe or SiC.

21. The image display device according to claim 20, wherein a half-value width of an emission spectrum of the core part of the semiconductor phosphor microparticle is 40 nm or less.

22. The image display device according to claim 20, wherein standard deviation of particle diameter distribution of the core part of the semiconductor phosphor microparticle is 15% or less of mean particle diameter of the core part of the semiconductor phosphor microparticle.

23. The image display device according to claim 20, comprising a white light emitting device including the light emitting element and the semiconductor phosphor microparticle, and a color filter.

24. The image display device according to claim 20, comprising the light emitting element, and a wavelength conversion member including the semiconductor phosphor microparticle.

25. A light emitting device comprising:
a light emitting element, and
a semiconductor phosphor microparticle having a core/shell structure having a core part and a shell part that covers the core part and absorbs at least a part of the light emitted by the light emitting element, and
including a UV to blue-violet luminescent light emitting element, a blue luminescent semiconductor phosphor microparticle, a green luminescent semiconductor phosphor microparticle and a red luminescent semiconductor phosphor microparticle.