JP2005232305A - Fluorescent substance of alkaline earth metal aluminate, and light-emitting device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a fluorescent substance of an alkaline earth metal aluminate capable of being efficiently exited by long wave-length ultraviolet rays, emitting green light, and having good light resistance; and to provide a light-emitting device having excellent light-emitting characteristics by using the fluorescent substance. <P>SOLUTION: The fluorescent substance of the alkaline earth metal aluminate contains calcium, aluminum, cerium, terbium and oxygen as basic constituent elements. The ratio of the mols of the aluminum to the mols of the calcium contained in the fluorescent substance is regulated so as to be ≥1.0 and ≤10.0. The fluorescent substance of the alkaline earth metal aluminate is efficiently exited by the long wave-length ultraviolet rays and emits the green light. The fluorescent substance of the alkaline earth metal aluminate has a high light-emitting luminance and the excellent light resistance. The light-emitting device using the fluorescent substance has the high light-emitting efficiency and excellent light-emitting characteristics. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an alkaline earth metal aluminate phosphor that is efficiently excited by long-wavelength ultraviolet light and emits green light, and a light-emitting device using the same.

  In recent years, various light emitting diodes and laser diodes have been developed as semiconductor light emitting devices. Such a semiconductor light emitting device takes advantage of low voltage drive, small size, light weight, thin shape, long life, high reliability and low power consumption, and as a light source such as a display, backlight, indicator, etc. Some are being replaced. In particular, a light-emitting device that uses a nitride semiconductor as a light-emitting element that can emit light efficiently on the short wavelength side from the ultraviolet region to the visible region has been developed. Blue and green LEDs with a well structure of 10 candela or more are being commercialized. Further, LEDs of various emission colors combining such a nitride semiconductor light emitting element and a phosphor are disclosed in Japanese Patent Laid-Open No. 9-153645, etc., but LEDs that emit light in various wavelength regions in a wider field are disclosed. At present, when high brightness is required, it is not sufficient and further improvement is required.

For white LEDs that combine nitride semiconductor light-emitting elements and phosphors, (1) excite yellow phosphors with blue LEDs, and (2) excite R, G, B phosphors with purple and ultraviolet LEDs. All are suitable as a white light source, but the luminous flux is weak and improvement is required. For example, in the method of (2), the Illuminating Society Journal 85 (2001) 273 uses an ultraviolet LED as an excitation source, Y ₂ O ₂ S: Eu as a red phosphor, ZnS: Cu, Al, blue as a green phosphor. Although a white LED using (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu as a phosphor has been disclosed, the luminous flux was not sufficient. In addition, since the ZnS: Cu, Al phosphor used as the green phosphor has poor light resistance, there is a problem in using it in an LED light emitting device that is required to withstand a long period of time from direct sunlight.

JP-A-9-153645 Journal of the Illuminating Engineering Society of Japan 85 (2001) 273

  The present invention has been made to solve such problems. An object of the present invention is to provide a light-resistant alkaline earth metal aluminate phosphor that is efficiently excited by long-wavelength ultraviolet light and emits green light, and further, has excellent emission characteristics using the phosphor. A light emitting device is provided.

  In order to achieve the above object, the present inventors have conducted intensive studies. As a result, alkaline earth metal aluminate phosphors having a specific composition have high emission luminance due to long-wavelength ultraviolet excitation, and this phosphor was used. The inventors have newly found that light emitting devices such as light emitting diodes have excellent light emitting characteristics, and have completed the present invention.

(1) The phosphor of the present invention is an alkaline earth metal aluminate phosphor containing calcium, aluminum, cerium, terbium, and oxygen as basic constituent elements, and aluminum relative to the number of moles of calcium contained in the phosphor. The ratio of the number of moles is in the range of 1.0 or more and 10.0 or less. The molar ratio is more preferably in the range of 2.0 or more and 8.4 or less, and further preferably in the range of 3.0 or more and 6.6 or less. The ratio of the number of moles of cerium to the number of moles of calcium contained in the phosphor is preferably in the range of 0.03 or more and 0.80 or less, more preferably in the range of 0.046 or more and 0.60 or less. The range of 0.076 or more and 0.40 or less is more preferable. The ratio of the number of moles of terbium to the number of moles of calcium contained in the phosphor is preferably in the range of 0.030 or more and 0.84 or less, more preferably in the range of 0.046 or more and 0.62 or less. The range of 074 or more and 0.40 or less is more preferable.

(2) The alkaline earth metal aluminate phosphor according to (1), wherein the phosphor of the present invention substitutes a part of the calcium with at least one element selected from magnesium, strontium, barium and zinc. It is. The ratio of the number of moles of the substitution element to the total number of moles of calcium element and substitution element contained in the phosphor is preferably in the range of 0 or more and 0.90 or less, more preferably in the range of 0 or more and 0.60 or less. As described above, the range of 0.30 or less is more preferable.

(3) The phosphor of the present invention is characterized in that the general formula is represented by the following formula.
_{(Ca 1-a, M a} ) O · αAl 2 O 3 · βCe 2 O 3 · γTb 2 O 3
(M is at least one element selected from Mg, Sr, Ba and Zn, 0 ≦ a ≦ 0.9, 0.5 ≦ α ≦ 5.0, 0.015 ≦ β ≦ 0.40,. 015 ≦ γ ≦ 0.42)

  The a value is more preferably in the range of 0 ≦ a ≦ 0.60, and more preferably in the range of 0 ≦ a ≦ 0.30. The α value is more preferably in the range of 1.0 ≦ α ≦ 4.2, and further preferably in the range of 1.5 ≦ α ≦ 3.3. Further, the β value is more preferably in the range of 0.023 ≦ β ≦ 0.30, and further preferably in the range of 0.038 ≦ β ≦ 0.20. The value of γ is more preferably in the range of 0.023 ≦ γ ≦ 0.31, and further preferably in the range of 0.037 ≦ γ ≦ 0.20.

(4) The phosphor of the present invention is the alkaline earth metal aluminate phosphor according to any one of (1) to (3), which emits light when excited by long-wavelength ultraviolet light having a wavelength in the range of at least 310 to 390 nm. It is suitable for use in LED light-emitting devices using ultraviolet LEDs as excitation sources, high-pressure mercury lamps in which 365-nm ultraviolet rays are the main excitation source, and light-emitting screens such as decorative plates mixed in concrete or glass. it can.

(5) A light emitting device of the present invention is a light emitting device using the alkaline earth metal aluminate phosphor according to any one of (1) to (4), and is a light emitting device such as an LED light emitting device or a high pressure mercury lamp. is there.

(6) The light-emitting device of the present invention absorbs a part of light emitted by the light-emitting element whose light-emitting layer is a semiconductor and emits light having a wavelength different from the wavelength of the absorbed light. In a light emitting device comprising a photoluminescence phosphor,
a) The light-emitting element is an LED chip that emits long-wavelength ultraviolet light whose light-emitting layer is a gallium nitride-based semiconductor containing Al and / or In and whose emission spectrum has a peak wavelength in the range of at least 310 to 390 nm,
b) The photoluminescence phosphor has an alkali spectrum according to (1) to (4), wherein the peak wavelength of the emission spectrum is in the range of at least 543 to 547 nm and the peak wavelength of the excitation spectrum is in the range of at least 310 to 390 nm. It contains an earth metal aluminate phosphor.

  Thus, an LED light emitting device including an LED chip that emits long-wavelength ultraviolet light and a photoluminescent phosphor containing an alkaline earth metal aluminate phosphor that is excited to emit green light and emits green light has various emission colors. And has excellent light emission characteristics. In particular, a white LED light emitting device having a blue light emitting phosphor and a red light emitting phosphor in addition to the green light emitting alkaline earth metal aluminate phosphor has high luminous efficiency.

In addition to the alkaline earth metal aluminate phosphor, (Sr, Ca, Ba, Mg) ₅ (PO ₄ ) ₃ (Cl, Br): Eu, Mn, (Sr, Ca, Ba, Mg) ₅ (PO ₄ ) ₃ Cl: halophosphate phosphor such as Eu, (Sr, Ca, Ba, Mg) ₂ SiO ₄ : silicate phosphor such as Eu, (Ca, Ba, Sr) ₂ B ₅ O ₉ Cl: borate phosphor such as Eu, Mn, SrAl ₂ O ₄ : Eu, Sr ₄ Al ₁₄ O ₂₅ : Eu, CaAl ₂ O ₄ : Eu, Mn, BaMg ₂ Al ₁₆ O ₂₇ : Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn, BaMgAl ₁₀ O ₁₇ : Alkaline earth metal aluminate phosphor such as Eu, Mn, Y ₃ Al ₅ O ₁₂ : Rare earth aluminate phosphor such as Ce, La ₂ O ₂ S: _{Eu, Y} 2 O _{S: Eu, Gd 2 O 2} S: rare earth oxysulfide phosphors such as Eu, ZnS: zinc sulfide phosphor such as _Cu, Zn 2 _GaO 4: gallium phosphor such as Mn, (Mg, Ca, Sr , Ba) having at least one phosphor selected from sulfide phosphors such as Ga ₂ S ₄ : Eu and nitride phosphors such as (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu. LED light-emitting devices exhibit various emission colors and have excellent emission characteristics.

  An alkaline earth metal aluminate phosphor having calcium, aluminum, cerium, terbium and oxygen as basic constituent elements, wherein the ratio of the number of moles of aluminum to the number of moles of calcium contained in the phosphor is 1.0 or more The alkaline earth metal aluminate phosphor of the present invention in a range of 10.0 or less is a phosphor having high emission luminance that is excited efficiently by long-wave ultraviolet light and emits green light, and has excellent light resistance. In addition, a light-emitting device using the same has high light emission efficiency and excellent light emission characteristics.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies the light emitting device and the phosphor for the light emitting device for embodying the technical idea of the present invention, and the present invention describes the light emitting device and the phosphor for the light emitting device as follows. Not specific to anything.

  Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely explanations. It's just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

  FIG. 1 is a schematic sectional view of a light emitting device. In the light emitting device of FIG. 1, a semiconductor light emitting element 2 is attached to a recess in the center of the package 1, and the electrode of the light emitting element 2 and the electrode of the package 1 are connected by a wire 4. A predetermined amount of a binder in which a phosphor is dispersed is sealed in a recess in the center of the package 1 to form a phosphor layer 3. A part of the light emitted from the semiconductor light emitting element 2 is transmitted through the phosphor layer 3, and part of the light is converted into light having a longer wavelength by the phosphor layer 3, and the transmitted light and the converted light are mixed to emit light from the semiconductor light emitting device. Become. By adjusting the phosphor layer 3, semiconductor light emitting devices of various chromaticities including white are formed.

[Light emitting element]
A light emitting element can be used as the excitation light source. In this specification, the light emitting element includes not only a semiconductor light emitting element such as a light emitting diode (LED) or a laser diode (LD) but also an element for obtaining light emission by vacuum discharge or light emission from thermoluminescence. In the present invention, a semiconductor light emitting device is preferable and will be described in detail below.

(Semiconductor light emitting device)
In the present invention, the semiconductor light emitting element is preferably a semiconductor light emitting element having a light emitting layer capable of emitting a light emission wavelength capable of efficiently exciting the phosphor. Examples of the material of such a semiconductor light emitting device include various semiconductors such as BN, SiC, ZnSe, GaN, InGaN, InAlGaN, AlGaN, BAlGaN, and BInAlGaN. Similarly, these elements may contain Si, Zn, or the like as an impurity element to serve as a light emission center. As a material for a light emitting layer capable of efficiently emitting a short wavelength of visible light from an ultraviolet region capable of efficiently exciting a phosphor, a nitride semiconductor (for example, a nitride semiconductor containing Al or Ga, a nitride containing In or Ga, etc.) As the physical semiconductor, In _x Al _y Ga _1-xy N (0 ≦ x, 0 ≦ y, x + y ≦ 1)) is more preferably cited. In the present invention, a gallium nitride-based semiconductor light-emitting element obtained by adjusting the amount of Al or In so that the main emission peak is in the range of 310 to 390 nm is preferably used.

  As a semiconductor structure, a homostructure having a MIS junction, a PIN junction, a pn junction, or the like, a heterostructure, or a double hetero configuration is preferably exemplified. Various emission wavelengths can be selected depending on the semiconductor layer material and the mixed crystal ratio. Further, the output can be further improved by adopting a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed in a thin film that produces a quantum effect.

  When a nitride semiconductor is used, a material such as sapphire, spinel, SiC, Si, ZnO, GaAs, or GaN is preferably used for the semiconductor substrate. In order to form a nitride semiconductor with good crystallinity with high productivity, it is preferable to use a sapphire substrate. A nitride semiconductor can be formed on the sapphire substrate using HVPE, MOCVD, or the like. A buffer layer made of GaN, AlN, GaAIN or the like is grown on the sapphire substrate at a low temperature to form a non-single crystal, and a nitride semiconductor having a pn junction is formed thereon.

As an example of a light emitting device capable of efficiently emitting light in an ultraviolet region having a pn junction using a nitride semiconductor, SiO ₂ is formed in a stripe shape on the buffer layer substantially perpendicular to the orientation flat surface of the sapphire substrate. GaN is grown on the stripes using EHV (Epitaxial Lateral Over Growth GaN) using the HVPE method. Subsequently, a first contact layer formed of n-type gallium nitride, a first cladding layer formed of n-type aluminum nitride / gallium, a well layer of indium nitride / aluminum / gallium, and aluminum nitride / gallium are formed by MOCVD. An active layer having a multiple quantum well structure in which a plurality of barrier layers are stacked, a second cladding layer formed of p-type aluminum nitride / gallium, and a second contact layer formed of p-type gallium nitride are sequentially stacked. Examples include a double hetero configuration. The active layer may be formed into a ridge stripe shape and sandwiched between guide layers, and a resonator end face may be provided to provide a semiconductor laser device usable in the present invention.

  Nitride semiconductors exhibit n-type conductivity without being doped with impurities. When forming a desired n-type nitride semiconductor, for example, to improve luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C, etc. as an n-type dopant. On the other hand, when forming a p-type nitride semiconductor, it is preferable to dope p-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba. Since nitride semiconductors are not easily converted to p-type by simply doping with a p-type dopant, it is preferable to reduce resistance by heating in a furnace or plasma irradiation after introducing the p-type dopant. When a sapphire substrate is not used, the contact layer is exposed by etching from the p-type side to the surface of the first contact layer. A light emitting element made of a nitride semiconductor can be formed by cutting the semiconductor wafer into chips after forming electrodes on each contact layer.

Further, in the semiconductor light emitting device used in the present invention, the sheet resistance of the n-type contact layer formed at an impurity concentration of 10 ¹⁷ to 10 ²⁰ / cm ³ and the sheet resistance of the translucent p electrode satisfy Rp ≧ Rn. It is adjusted to be related. The n-type contact layer is preferably formed to a film thickness of, for example, 3 to 10 μm, more preferably 4 to 6 μm, and the sheet resistance is estimated to be 10 to 15Ω / □, so that Rp at this time is the sheet resistance value. It is good to form in a thin film so that it may have the above sheet resistance values. The translucent p-electrode may be formed of a thin film having a thickness of 150 μm or less.

  In the case where the translucent p-electrode is formed of a multilayer film or an alloy composed of one kind selected from the group of gold and platinum group elements and at least one other element, the translucent p-electrode The sheet resistance may be adjusted in that the stability and reproducibility are improved when the sheet resistance is adjusted depending on the content of the contained gold or platinum group element. In addition, since gold or platinum group elements have a high absorption coefficient in the wavelength region of the semiconductor light emitting device of the present invention, the smaller the amount of gold or platinum group elements contained in the translucent p-electrode, the better the transparency. In the conventional semiconductor light emitting device, the relationship of sheet resistance is Rp ≦ Rn. However, in the present invention, Rp ≧ Rn, and therefore the translucent p-electrode is formed in a thin film as compared with the conventional one. However, at this time, thinning can be performed satisfactorily by reducing the content of gold or platinum group elements.

  In the semiconductor light emitting device used in the present invention, the sheet resistance RnΩ / □ of the n-type contact layer and the sheet resistance RpΩ / □ of the translucent p electrode have a relationship of Rp ≧ Rn. It is difficult to measure Rn after it is formed as a semiconductor light emitting device, and it is practically impossible to know the relationship between Rp and Rn, but what is the relationship between Rp and Rn from the state of the light intensity distribution during light emission? You can know if they are in a relationship.

  In addition, the p-side pedestal electrode and the n-electrode may be arranged at the center of each side of the element, or each may be arranged at the corners facing the element.

  When the translucent p-electrode and the n-type contact layer have a relationship of Rp ≧ Rn, providing a p-side pedestal electrode in contact with the translucent p-electrode and having an extended conductive portion further improves external quantum efficiency. Is expected. There is no limitation on the shape and direction of the extended conductive portion, and when the extended conductive portion is on the satellite, it is preferable because the area for blocking light is reduced, but a mesh shape may be used. Further, the shape may be a curved shape, a lattice shape, a branch shape, or a hook shape in addition to the straight shape. At this time, since the light shielding effect increases in proportion to the total area of the p-side pedestal electrode, it is preferable to design the line width and length of the extended conductive portion so that the light shielding effect does not exceed the light emission enhancing effect.

  In addition, the phosphor can be attached with various binders such as a resin which is an organic material and a glass which is an inorganic material. When an organic substance is used as the binder, a transparent resin excellent in weather resistance such as an epoxy resin, an acrylic resin, or silicone is preferably used as a specific material. In particular, silicone is preferable because it is excellent in reliability and can improve the dispersibility of the phosphor.

Moreover, an inorganic substance can also be used as a binder. As a specific method, a precipitation method, a sol-gel method, or the like can be used. For example, a phosphor, silanol (Si (OEt) ₃ OH), and ethanol are mixed to form a slurry. After the slurry is discharged from a nozzle, the slurry is heated at 300 ° C. for 3 hours to change the silanol to SiO ₂ . The phosphor can be fixed at a desired location. In particular, when the phosphor is attached to the window portion, it is preferable to use an inorganic substance that is close to the thermal expansion coefficient of the window portion because the phosphor can be satisfactorily adhered to the window portion.

  Further, an inorganic binder can be used as a binder. The binder is a so-called low-melting glass, is a fine particle and is preferably very stable in the binder with little absorption with respect to radiation from the ultraviolet to the visible region, and was obtained by a precipitation method. Alkaline earth borates, which are fine particles, are suitable.

  In addition, when attaching a phosphor having a large particle size, a binder whose particle is an ultrafine powder even if the melting point is high, such as silica, alumina, or a fine-sized alkaline earth metal obtained by a precipitation method Pyrophosphate, orthophosphate, etc. are preferably used. These binders can be used alone or mixed with each other.

  Here, a method of applying the binder will be described. In order to sufficiently enhance the binding effect, the binder is preferably used in the form of a slurry by wet pulverization in a vehicle and used as a binder slurry. A vehicle is a high viscosity solution obtained by dissolving a small amount of a binder in an organic solvent or deionized water. For example, an organic vehicle can be obtained by adding 1 wt% of nitrocellulose as a binder to butyl acetate as an organic solvent.

  A phosphor is contained in the binder slurry thus obtained to prepare a coating solution. The added amount of the slurry in the coating solution can be set such that the total amount of the binder in the slurry is about 1 to 3% by weight with respect to the phosphor amount in the coating solution. In order to suppress a decrease in the luminous flux maintenance factor, it is preferable that the amount of the binder added is small. Such a coating solution is applied to the back surface of the window portion. After that, hot air or hot air is blown to dry. Finally, baking is performed at a temperature of 400 ° C. to 700 ° C., and the vehicle is scattered to adhere the phosphor layer to a desired place with a binder.

(Diffusion agent)
Furthermore, in the present invention, a diffusing agent may be contained in addition to the phosphor. As a specific diffusing agent, barium titanate, titanium oxide, aluminum oxide, silicon oxide or the like is preferably used. As a result, a light emitting device having good directivity can be obtained.

  Here, in this specification, the diffusing agent refers to those having a center particle diameter of 1 nm or more and less than 5 μm. A diffusing agent having a particle size of 1 μm or more and less than 5 μm is preferable because it can diffuse irregularly the light from the phosphor and suppress color unevenness that tends to occur when a phosphor having a large particle size is used. On the other hand, a diffusing agent of 1 nm or more and less than 1 μm has a low interference effect with respect to the light wavelength from the light emitting element, but can increase the resin viscosity without lowering the luminous intensity. This makes it possible to disperse the phosphor in the resin almost uniformly in the syringe and maintain the state when arranging the phosphor-containing resin by potting or the like, and the particle size is relatively difficult to handle. Even when a large phosphor is used, it is possible to produce with high yield. Thus, the action of the diffusing agent in the present invention varies depending on the particle size range, and can be selected or combined according to the method of use.

(Filler)
Furthermore, in the present invention, the color conversion member may contain a filler in addition to the phosphor. The specific material is the same as that of the diffusing agent, but the diffusing agent has a central particle size different from that of the diffusing agent. When the filler having such a particle size is contained in the translucent resin, the chromaticity variation of the light emitting device is improved by the light scattering action, and the thermal shock resistance of the translucent resin can be enhanced. As a result, even when used at high temperatures, it is possible to prevent disconnection of the wire that electrically connects the light emitting element and the external electrode, separation from the bottom surface of the light emitting element and the bottom surface of the concave portion of the package, etc. with high reliability. A light emitting device is obtained. Furthermore, the fluidity of the resin can be adjusted to be constant for a long time, and a sealing member can be formed in a desired place, and mass production can be performed with a high yield.

  The filler preferably has a particle size and / or shape similar to that of the phosphor. Here, in this specification, the similar particle diameter means a case where the difference in the central particle diameter of each particle is less than 20%, and the similar shape means an approximate degree of each particle diameter with a perfect circle. This represents a case where the difference in the value of the degree of circularity (circularity = perimeter length of a perfect circle equal to the projected area of the particle / perimeter length of the projected particle) is less than 20%. By using such a filler, the phosphor and the filler interact with each other, the phosphor can be favorably dispersed in the resin, and color unevenness is suppressed.

[Phosphor]
The phosphor converts light emitted from the light emitting element into another emission wavelength. A phosphor is used as a wavelength conversion material that emits light having a wavelength longer than the wavelength of the absorbed light, and desired light can be emitted to the outside by color mixture of light emitted from the light emitting element and converted light of the phosphor. The phosphor is excited by light emitted from a semiconductor light emitting layer of the LED, for example, as an excitation light source and emits light.

  The phosphor of the present invention is an alkaline earth metal aluminate phosphor having calcium, aluminum, cerium, terbium and oxygen as basic constituent elements, and the number of moles of aluminum relative to the number of moles of calcium contained in the phosphor. The ratio is preferably 1.0 or more and 10.0 or less. The molar ratio is more preferably in the range of 2.0 or more and 8.4 or less, and further preferably in the range of 3.0 or more and 6.6 or less. Even if it is less than 1.0 or exceeds 10.0, the light emission luminance due to the long-wavelength ultraviolet excitation is lowered. Further, the ratio of the number of moles of cerium to the number of moles of calcium contained in the phosphor is preferably in the range of 0.030 or more and 0.80 or less, more preferably in the range of 0.046 or more and 0.60 or less. The range of 0.076 or more and 0.40 or less is more preferable. Even if it is less than 0.030 or exceeds 0.80, the light emission luminance due to the excitation of the long wavelength ultraviolet light is lowered. The ratio of the number of moles of terbium to the number of moles of calcium contained in the phosphor is preferably in the range of 0.030 or more and 0.82 or less, more preferably in the range of 0.046 or more and 0.62 or less. The range of 074 or more and 0.40 or less is more preferable. Even if it is less than 0.030 or exceeds 0.84, the light emission luminance due to the excitation of the long wavelength ultraviolet light is lowered.

  The peak wavelength of the emission spectrum of the phosphor of the present invention is at least in the range of 543 to 547 nm, and the peak wavelength of the excitation spectrum is in the range of at least 310 to 390 nm.

  The phosphor of the present invention is preferably an alkaline earth metal aluminate phosphor in which a part of calcium of the phosphor is substituted with at least one element selected from magnesium, strontium, barium and zinc. Even when a part of calcium is substituted with such a divalent metal element, an alkaline earth metal aluminate phosphor having high emission luminance can be obtained. The ratio of the number of moles of the substitution element to the total number of moles of calcium element and substitution element contained in the phosphor is preferably in the range of 0 or more and 0.90 or less, more preferably in the range of 0 or more and 0.60 or less. As described above, the range of 0.30 or less is more preferable. If it exceeds 0.90, the luminance of light emitted by the long wavelength ultraviolet light excitation is lowered.

The phosphor of the present invention is preferably an alkaline earth metal aluminate phosphor represented by the following formula.
_{(Ca 1-a, M a} ) O · αAl 2 O 3 · βCe 2 O 3 · γTb 2 O 3
(M is at least one element selected from Mg, Sr, Ba and Zn, 0 ≦ a ≦ 0.9, 0.5 ≦ α ≦ 5.0, 0.015 ≦ β ≦ 0.40,. 015 ≦ γ ≦ 0.42)

  The a value is more preferably in the range of 0 ≦ a ≦ 0.60, and more preferably in the range of 0 ≦ a ≦ 0.30. The α value is more preferably in the range of 1.0 ≦ α ≦ 4.2, and further preferably in the range of 1.5 ≦ α ≦ 3.3. Further, the β value is more preferably in the range of 0.023 ≦ β ≦ 0.30, and further preferably in the range of 0.038 ≦ β ≦ 0.20. The value of γ is more preferably in the range of 0.023 ≦ γ ≦ 0.31, and further preferably in the range of 0.037 ≦ γ ≦ 0.20. In such a composition range, it is possible to obtain an alkaline earth metal aluminate phosphor having a high emission luminance by excitation with a long wavelength ultraviolet ray.

  Next, the characteristics will be described with reference to the drawings. FIG. 2 shows the emission spectrum of the phosphor of Example 1 of the present invention excited by 365 nm, and FIG. 3 shows the excitation spectrum. From FIG. 2, it can be seen that the phosphor of the present invention has a peak wavelength of the emission spectrum in the range of 543 to 547 nm and emits green light by long wavelength ultraviolet excitation. FIG. 3 also shows that the phosphor of the present invention has an excitation spectrum peak wavelength in the range of 310 to 390 nm and is efficiently excited by long-wavelength ultraviolet light.

When a CaO · αAl ₂ O ₃ · 0.07Ce ₂ O ₃ · 0.07Tb ₂ O ₃ phosphor was produced in the same manner as in Example 1, the α value was changed in the range of 0 <α ≦ 6.0. FIG. 4 shows the relationship between the relative luminance (%) of the phosphors excited by 365 nm and the α value. Here, the relative luminance (%) represents a relative value when the luminance of the phosphor of Example 1 by the excitation at 365 nm is 100%. From this figure, it can be seen that the luminance increases as the α value increases, the luminance is highest when the α value is around 2.2, and decreases when the α value is exceeded. It can be seen that the luminance by excitation at 365 nm is preferably 70% or more, and preferably in the range of 0.5 ≦ α ≦ 5.0. The luminance is 85% or more in the range of 1.0 ≦ α ≦ 4.2 and 100% or more in the range of 1.5 ≦ α ≦ 3.3.

FIG. 5 shows a relative relative to the excitation of 365 nm when the β value is changed in the range of 0 <β ≦ 0.5 in the CaO.2.2Al ₂ O ₃ · βCe ₂ O ₃ · 0.07Tb ₂ O ₃ phosphor. The relationship between luminance (%) and β value is shown. From this figure, it can be seen that the luminance increases as the β value increases, the luminance is highest when the β value is around 0.07, and decreases when the β value is exceeded. It can be seen that the luminance by excitation at 365 nm is preferably 70% or more, and preferably in the range of 0.015 ≦ β ≦ 0.40. The luminance is 85% or more in the range of 0.023 ≦ β ≦ 0.30 and 100% or more in the range of 0.038 ≦ β ≦ 0.20.

6, in _{CaO · 2.2Al 2 O 3 · 0.07Ce} 2 O 3 · γTb 2 O 3 phosphor, relative by 365nm excitation when the gamma value is changed in a range of 0 <γ ≦ 0.5 The relationship between luminance (%) and γ value is shown. From this figure, it can be seen that the luminance increases as the γ value increases, the luminance is highest when the γ value is around 0.07, and decreases when the γ value is exceeded. It can be seen that the luminance by excitation at 365 nm is preferably 70% or more, and preferably in the range of 0.015 ≦ γ ≦ 0.42. The luminance is 85% or more in the range of 0.023 ≦ γ ≦ 0.31, and 100% or more in the range of 0.037 ≦ γ ≦ 0.20.

The preferable ranges of α, β, and γ are 0.5 ≦ α ≦ 5.0 and 0.015 ≦ β ≦ 0 in the alkaline earth metal aluminate phosphor whose general formula is represented by the following formula. In the range of .40 and 0.015 ≦ γ ≦ 0.42, an alkaline earth metal aluminate phosphor having high emission luminance by long-wavelength ultraviolet excitation is obtained.
_{(Ca 1-a, M a} ) O · αAl 2 O 3 · βCe 2 O 3 · γTb 2 O 3
(M is at least one element selected from Mg, Sr, Ba and Zn, 0 ≦ a ≦ 0.9)

In addition to the phosphor of the present invention, other phosphors can be mixed and used. For example, halophosphoric acid such as (Sr, Ca, Ba, Mg) ₅ (PO ₄ ) ₃ (Cl, Br): Eu, Mn, (Sr, Ca, Ba, Mg) ₅ (PO ₄ ) ₃ Cl: Eu Salt phosphors, silicate phosphors such as (Sr, Ca, Ba, Mg) ₂ SiO ₄ : Eu, borate phosphors such as (Ca, Ba, Sr) ₂ B ₅ O ₉ Cl: Eu, Mn, SrAl ₂ O ₄ : Eu, Sr ₄ Al ₁₄ O ₂₅ : Eu, CaAl ₂ O ₄ : Eu, Mn, BaMg ₂ Al ₁₆ O ₂₇ : Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn, BaMgAl ₁₀ O ₁₇ : Alkaline earth metal aluminate phosphors such as Eu and Mn, rare earth aluminate phosphors such as Y ₃ Al ₅ O ₁₂ : Ce, La ₂ O ₂ S: Eu, Y ₂ O ₂ S: Eu, Gd ₂ Rare earth acid sulfur such as O ₂ S: Eu Fluoride phosphor, zinc sulfide phosphor such as ZnS: Cu, gallate phosphor such as Zn ₂ GaO ₄ : Mn, sulfide phosphor such as (Mg, Ca, Sr, Ba) Ga ₂ S ₄ : Eu, A nitride phosphor such as (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu is preferable. An LED light-emitting device having at least one of these phosphors in addition to the phosphor of the present invention exhibits various emission colors and has excellent emission characteristics.

  The phosphor may be coated on the surface as necessary. This further prevents the phosphor from being deteriorated by external factors such as heat, humidity, and ultraviolet rays. Moreover, ions are eluted from the phosphor surface, and the other members of the semiconductor light emitting element are also prevented from being adversely affected.

The phosphor of the present invention is obtained as follows. As a phosphor raw material, calcium compounds, aluminum compounds, cerium compounds, terbium compounds are used, or in addition to these compounds, at least one compound selected from magnesium compounds, strontium compounds, barium compounds, zinc compounds is used, for compounds, for example, at least one element of the general formula _{(Ca 1-a, M a} ) O · αAl 2 O 3 · βCe 2 O 3 · γTb 2 O 3 (M being selected Mg, Sr, Ba and Zn , 0 ≦ a ≦ 0.9, 0.5 ≦ α ≦ 5.0, 0.015 ≦ β ≦ 0.40, 0.015 ≦ γ ≦ 0.42). Or a flux is added to and mixed with these phosphor raw materials to obtain a raw material mixture. After filling this raw material mixture into a crucible, it is fired at 800-1500 ° C. in a reducing atmosphere, and after cooling, the phosphor of the present invention represented by the above general formula is obtained by dispersion treatment.

  As the phosphor raw material, an oxide or a compound such as a carbonate or hydroxide that becomes an oxide by thermal decomposition is preferably used. Moreover, the coprecipitate which contains all or one part of each metal element which comprises a fluorescent substance can also be used as a fluorescent substance raw material. For example, when an aqueous solution such as alkali or carbonate is added to an aqueous solution containing these elements, a coprecipitate can be obtained, which can be used after being dried or thermally decomposed. Moreover, as a flux, a fluoride, a borate, etc. are preferable, and it adds in 0.01-1.0 weight part with respect to 100 weight part of fluorescent substance raw materials. The firing atmosphere is preferably a reducing atmosphere, and more preferably a hydrogen / nitrogen mixed gas atmosphere containing several percent of hydrogen. The firing temperature is preferably 800 to 1500 ° C., and a phosphor having a target center particle diameter can be obtained. More preferably, it is 900-1400 degreeC.

  The center particle diameter of the phosphor of the present invention is preferably in the range of 1 to 100 μm, more preferably in the range of 5 to 50 μm, and still more preferably in the range of 5 to 15 μm. Phosphors smaller than 1 μm tend to form aggregates. On the other hand, a phosphor having a particle size range of 5 to 50 μm has a high light absorption rate and conversion efficiency, and easily forms a light emitting layer. As described above, the mass productivity of the light-emitting device is improved by including a phosphor having a large particle diameter and having optically excellent characteristics. Here, the center particle size is a particle size value when the integrated value is 50% in the volume-based particle size distribution curve, and the volume-based particle size distribution curve can be obtained by measuring the particle size distribution by a laser diffraction / scattering method. Specifically, in an environment where the temperature is 25 ° C. and the humidity is 70%, each substance is dispersed in an aqueous solution of sodium hexametaphosphate having a concentration of 0.05%, and a laser diffraction particle size distribution analyzer (SALD-2000A). Is obtained by measuring in a particle size range of 0.03 to 700 μm. Moreover, it is preferable that the fluorescent substance which has the said center particle size value is contained frequently, and 20%-50% of frequency values are preferable. By using a phosphor having a small variation in particle size in this way, a light emitting device having a favorable color tone with more suppressed color unevenness can be obtained.

  Examples of the present invention will be described below, but it goes without saying that the present invention is not limited to specific examples.

[Example 1]
<Phosphor>
As a phosphor material,
CaCO ₃ ... 1.00 mol (100.0 g)
Al ₂ O ₃ ... 2.19 mol (223.2 g)
CeO ₂ ... 0.125 mol (21.5 g)
・ Tb ₄ O ₇ ... 0.0313 mol (23.4 g)
In addition, 0.9 g of H ₃ BO ₃ was added as a flux to this and mixed well, filled in an alumina crucible, and 300 ° C./hr from room temperature to 1250 ° C. in a mixed gas atmosphere of hydrogen and nitrogen. The temperature is raised at 1,250 ° C. for 3 hours. The obtained fired product is ball-milled in water, washed with water, separated, dried, passed through a sieve, and CaO · 2.19Al ₂ O ₃ · 0.0625Ce ₂ O ₃ · 0.0625Tb ₂ O ₃ having a center particle size of 10 µm. A phosphor is obtained. Table 1 shows the composition of the phosphor. This phosphor has an emission peak at 545 nm by excitation with ultraviolet light at 365 nm, the emission color is green, and the chromaticity coordinate values are x = 0.340 and y = 0.553. The peak wavelength of the excitation spectrum is 366 nm. These measurement results are shown in Table 2.

Next, an LED light-emitting device is manufactured using this phosphor.
<Light emitting device>
The LED chip uses a nitride semiconductor element having a 365 nm InAlGaN semiconductor having an emission peak in the ultraviolet region as a light emitting layer. More specifically, in the LED chip, TMG (trimethylgallium) gas, TMI (trimethylindium) gas, nitrogen gas and dopant gas are flowed together with a carrier gas on a cleaned sapphire substrate, and a nitride semiconductor is formed by MOCVD. Can be formed. A layer to be an n-type nitride semiconductor or a p-type nitride semiconductor is formed by switching between SiH ₄ and Cp ₂ Mg as the dopant gas.

  As an element structure of the LED chip, an undoped n-type GaN layer, an underlayer made of undoped GaN, a composition gradient AlGaN layer, an n-type cladding layer made of Si-doped AlGaN and an n-type contact layer are formed on a sapphire substrate. Next, a multi-quantum well structure is formed, in which three layers of a barrier layer made of AlGaN doped with Si and a well layer made of undoped InGaN are stacked as a light emitting layer. A p-type cladding layer made of AlGaN doped with Mg and a p-type contact layer are sequentially laminated on the light emitting layer (note that a GaN layer is formed on the sapphire substrate at a low temperature to serve as a buffer layer. Also, the p-type semiconductor is annealed at 400 ° C. or higher after film formation).

More specifically, a buffer layer made of GaN is grown at 200 ° C. on a sapphire substrate having a 2 inch φ, (0001) C plane as the main surface, and then the temperature is raised to 1050 ° C. An undoped GaN layer is grown to a thickness of 5 μm. Note that the film thickness to be grown is not limited to 5 μm, and it is desirable to grow the film thicker than the buffer layer and adjust the film thickness to 10 μm or less. Next, after the growth of the undoped GaN layer, the wafer is taken out of the reaction vessel, a striped photomask is formed on the surface of the GaN layer, and a SiO 2 having a stripe width of 15 μm and a stripe interval (window) of 5 μm is formed by a CVD apparatus. _A mask made of ₂ is formed to a thickness of 0.1 μm. After forming the mask, the wafer is set again in the reaction vessel, and undoped GaN is grown to a thickness of 10 μm at 1050 ° C. The crystal defect of the undoped GaN layer is 10 ¹⁰ / cm ² or more, but the crystal defect of the GaN layer is 10 ⁶ / cm ² or more.

(N-type gallium nitride compound semiconductor layer)
Next, an n-type cladding layer and n-type contact layer are formed through the following underlayer and composition gradient layer.

(Underlayer)
Buffer layer: Subsequently, using hydrogen and TMG (trimethylgallium) at 510 ° C. in a hydrogen atmosphere, a buffer layer made of GaN is grown on the substrate to a thickness of about 200 mm.
High-temperature growth layer: After growing the buffer layer, only TMG is stopped, the temperature is raised to 1050 ° C., and when it reaches 1050 ° C., TMG and ammonia are used as source gases, and a high-temperature growth nitride semiconductor made of undoped GaN is 5 μm. Growing with a film thickness of

(Composition gradient layer)
Composition gradient layer: After growing the high temperature growth layer, the composition gradient AlGaN layer is grown to a thickness of 0.4 μm using TMG, TMA, and ammonia as source gases at the same temperature. This composition gradient layer is for relaxing lattice mismatch between the high-temperature growth layer and the n-type cladding layer, and is n-type Al _0.07 Ga ₀ doped with 1 × 10 ¹⁹ / cm ^{3 of} Si from undoped GaN. _The Al alloy ratio and Si doping amount are gradually increased up to _.93 N.

(N-type cladding layer and n-type contact layer)
Next, an n-type clad layer / n-type contact layer made of n-type Al _0.07 Ga _0.93 N doped with Si at 1 × 10 ¹⁹ / cm ³ using TMG, TMA, ammonia, and silane at 1050 ° C. Is formed with a film thickness of 2.5 μm.

(Active layer)
Next, the barrier layer made of Al _0.09 Ga _0.91 N doped with Si at 1 × 10 ¹⁹ / cm ³ using TMI (trimethylindium), TMG, TMA as a source gas at a temperature of 900 ° C., A well layer made of undoped In _0.01 Ga _0.99 N is stacked thereon in the order of barrier layer A / well layer A / barrier layer B / well layer B / barrier layer C / well layer C / barrier layer D. To do. At this time, the barrier layers A, B, C, and D are formed to a thickness of 200 mm, and the well layers A, B, and C are formed to a thickness of 60 mm. Only the barrier layer D is undoped.

(P-type cladding layer)
Next, from Al _0.38 Ga _0.62 N doped with 1 × 10 ²⁰ / cm ^{3 of} Mg using TMG, TMA, ammonia, Cp ₂ Mg (cyclopentadienyl magnesium) at 1050 ° C. in a hydrogen atmosphere A p-type cladding layer is grown to a thickness of 270 mm.

(P-type contact layer)
Subsequently, the first p-type made of Al _0.07 Ga _0.93 N doped with 4 × 10 ¹⁸ / cm ^{3 of} Mg on the p-type cladding layer using TMG, TMA, ammonia, and Cp ₂ Mg. A second p-type contact made of Al _0.07 Ga _0.93 N doped with 1 × 10 ²⁰ / cm ³ Mg by adjusting the flow rate of the gas after growing the contact layer to a thickness of 0.1 μm The layer was grown to a thickness of 0.02 μm.

  After completion of the growth, the wafer is annealed at 700 ° C. in a reaction vessel in a nitrogen atmosphere to further reduce the resistance of the p-type layer.

  Next, the surface of each pn contact layer is exposed on the same side as the nitride semiconductor on the sapphire substrate by etching. Specifically, the wafer is taken out from the reaction vessel, a mask having a predetermined shape is formed on the surface, and etching is performed from the p-type gallium nitride compound semiconductor layer side by an RIE (reactive ion etching) apparatus, and the n-type contact layer To expose the surface.

(Translucent p electrode, pedestal electrode, n electrode)
Positive and negative pedestal electrodes are formed on each contact layer by sputtering. A metal thin film is formed on the entire surface of the p-type nitride semiconductor as a translucent electrode, and then a pedestal electrode is formed on a part of the translucent electrode. Specifically, after etching, a light-transmitting p-electrode (Ni / Au = 60/50) having a thickness of 110 mm so as to cover almost the entire surface of the p-type layer, and a film thickness of 0.5 μm on the p-electrode. A pedestal electrode made of Au and having three extended conductor portions is formed along the side at the corner of the light emitting element. On the other hand, an n-electrode containing W and Al is formed on the surface of the n-side contact layer exposed by etching so as to face the pedestal electrode. After a scribe line is drawn on the completed semiconductor wafer, it is divided by an external force to form LED chips that are semiconductor light emitting elements.

  On the other hand, a Kovar package is used as a housing of the light-emitting device. The Kovar package has a concave portion at the center and a base portion in which Kovar lead electrodes are inserted and fixed in an insulating and airtight manner on both sides of the concave portion. A Ni / Ag layer is provided on the surface of the package and the lead electrode. An LED chip is die-bonded with an Ag—Sn alloy in the recess of the package thus configured. Next, each electrode of the die-bonded LED chip and each lead electrode exposed from the bottom of the recess of the package are electrically connected with an Ag wire, and an LED light emitting device as shown in FIG. 1 is manufactured.

  When a current is passed through the light emitting device, ultraviolet light having a peak wavelength of 365 nm is emitted from the light emitting element 2. Using this ultraviolet ray as an excitation source, the phosphor layer 3 covering the light emitting element 2 emits green light. As a result, a green LED light emitting device having chromaticity coordinate values of x = 0.341 and y = 0.552 is obtained.

[Examples 2 to 7]
A phosphor is manufactured in the same manner as in Example 1 except that the raw materials are mixed at the ratio of the phosphor composition shown in Table 1 and fired at the firing temperature shown in Table 1. Table 2 shows the measurement results of these phosphors. The relative luminance (%) shown in Table 2 indicates a relative value when the luminance of the phosphor of Example 1 is set to 100% by 365 nm excitation.

[Examples 8 to 14]
In addition to CaCO ₃ , at least one compound selected from MgCO ₃ , SrCO ₃ , BaCO ₃ , and ZnO is used as the phosphor raw material, and the raw materials are mixed at the ratio of the phosphor composition shown in Table 1. A phosphor is produced in the same manner as in Example 1.

[Example 15]
The phosphor obtained in Example 1 as a green phosphor, (Sr, Ca, Ba, Mg) ₅ (PO ₄ ) ₃ (Cl, Br): Eu phosphor as a blue phosphor, and (Mg, In the same manner as in Example 1, using a Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu phosphor, a nitride semiconductor light emitting device having an emission spectrum peak wavelength of 365 nm as an excitation light source, chromaticity coordinate values Produces a white LED light emitting device with x = 0.313 and y = 0.321.

[Example 16]
The phosphor obtained in Example 1 as a green phosphor, (Sr, Ca, Ba, Mg) ₅ (PO ₄ ) ₃ (Cl, Br): Eu phosphor as a blue phosphor, and Gd ₂ O as a red phosphor Using a nitride semiconductor light emitting device having a ₂ S: Eu phosphor and a peak wavelength of an emission spectrum of 365 nm as an excitation light source, the chromaticity coordinate values are x = 0.322, y = A 0.330 white LED light-emitting device is produced.

[Example 17]
The phosphor obtained in Example 1 as a green phosphor, (Sr, Ca, Ba, Mg) ₅ (PO ₄ ) ₃ (Cl, Br): Eu phosphor as a blue phosphor, and (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu phosphor and Gd ₂ O ₂ S: Eu phosphor were used, and a nitride semiconductor light emitting device having an emission spectrum peak wavelength of 365 nm was used as an excitation light source. In the same manner as in Example 1, a white LED light emitting device having chromaticity coordinate values of x = 0.320 and y = 0.327 is manufactured.

From Tables 1 and 2, the phosphors of the present invention obtained in Examples 1 to 14 are alkaline earth metal aluminate phosphors whose general formulas are represented by the following formulas, and emission luminance due to long-wavelength ultraviolet excitation. Is high.
_{(Ca 1-a, M a} ) O · αAl 2 O 3 · βCe 2 O 3 · γTb 2 O 3
(M is at least one element selected from Mg, Sr, Ba and Zn, 0 ≦ a ≦ 0.9, 0.5 ≦ α ≦ 5.0, 0.015 ≦ β ≦ 0.40,. 015 ≦ γ ≦ 0.42)

  INDUSTRIAL APPLICABILITY The present invention can be used for illumination light sources, LED displays, backlight light sources such as mobile phones, traffic lights, illumination switches, in-vehicle stop lamps, various sensors, and various indicators.

1 is an example of a schematic cross-sectional view showing a light emitting device according to an embodiment of the present invention. 3 is a graph showing an emission spectrum of the phosphor of Example 1. 3 is a graph showing an excitation spectrum of the phosphor of Example 1. It is a figure which shows the relationship between the relative luminance (%) and alpha value of the fluorescent substance of this invention. It is a figure which shows the relationship between the relative luminance (%) of the fluorescent substance of this invention, and (beta) value. It is a figure which shows the relationship between the relative luminance (%) of the fluorescent substance of this invention, and (gamma) value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting device package 2 Semiconductor light emitting element 3 Phosphor layer wire 4 Wire

Claims (6)

  An alkaline earth metal aluminate phosphor having calcium, aluminum, cerium, terbium and oxygen as basic constituent elements, wherein the ratio of the number of moles of aluminum to the number of moles of calcium contained in the phosphor is 1.0 or more An alkaline earth metal aluminate phosphor characterized by having a range of 10.0 or less.   The alkaline earth metal aluminate phosphor according to claim 1, wherein a part of the calcium is substituted with at least one element selected from magnesium, strontium, barium and zinc. An alkaline earth metal aluminate phosphor, wherein the general formula is represented by the following formula:
_{(Ca 1-a, M a} ) O · αAl 2 O 3 · βCe 2 O 3 · γTb 2 O 3
(M is at least one element selected from Mg, Sr, Ba and Zn, 0 ≦ a ≦ 0.9, 0.5 ≦ α ≦ 5.0, 0.015 ≦ β ≦ 0.40,. 015 ≦ γ ≦ 0.42)   The alkaline earth metal aluminate phosphor according to any one of claims 1 to 3, wherein the alkaline earth metal aluminate phosphor emits light when excited by a long wavelength ultraviolet ray having a wavelength in a range of at least 310 to 390 nm.   A light emitting device using the alkaline earth metal aluminate phosphor according to claim 1. A light emitting device comprising: a light emitting element whose light emitting layer is a semiconductor; and a photoluminescence phosphor that absorbs part of the light emitted by the light emitting element and emits light having a wavelength different from the wavelength of the absorbed light. In
a) The light-emitting element is an LED chip that emits long-wavelength ultraviolet light whose light-emitting layer is a gallium nitride-based semiconductor containing Al and / or In and whose emission spectrum has a peak wavelength in the range of at least 310 to 390 nm,
The alkaline earth according to any one of claims 1 to 4, wherein the photoluminescence phosphor has an emission spectrum peak wavelength in the range of at least 543 to 547 nm and an excitation spectrum peak wavelength in the range of at least 310 to 390 nm. A light-emitting device comprising a metal aluminate phosphor.

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