(19)
(11)EP 3 495 449 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
13.05.2020 Bulletin 2020/20

(21)Application number: 18210485.1

(22)Date of filing:  05.12.2018
(51)International Patent Classification (IPC): 
C09K 11/77(2006.01)
C09K 11/02(2006.01)

(54)

WAVELENGTH CONVERTING MEMBER AND METHOD FOR PRODUCING THE SAME

WELLENLÄNGENUMWANDLUNGSELEMENT UND VERFAHREN ZUR HERSTELLUNG DAVON

ÉLÉMENT DE CONVERSION DE LONGUEUR D'ONDE ET SON PROCÉDÉ DE FABRICATION


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 08.12.2017 JP 2017236068

(43)Date of publication of application:
12.06.2019 Bulletin 2019/24

(73)Proprietor: NICHIA CORPORATION
Anan-shi Tokushima 774-8601 (JP)

(72)Inventor:
  • MURAZAKI, Yoshinori
    Tokushima, 774-8601 (JP)

(74)Representative: Vossius & Partner Patentanwälte Rechtsanwälte mbB 
Siebertstrasse 3
81675 München
81675 München (DE)


(56)References cited: : 
EP-A1- 1 670 070
JP-A- 2016 119 383
WO-A1-2017/170609
US-A1- 2008 258 110
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    CROSS-REFERENCE TO RELATED PATENT APPLICATION



    [0001] This application claims priority to Japanese Patent Application No. 2017-236068, filed on December 8, 2017.

    BACKGROUND


    Technical Field



    [0002] The present invention relates to a wavelength converting member that converts the wavelength of light emitted from, e.g., a light emitting diode (hereinafter also referred to as "LED") or a laser diode (hereinafter also referred to as "LD"), and a method for producing the same. In this specification, the "fluorescent material" is used in the same meaning as a "fluorescent phosphor".

    Description of Related Art



    [0003] A light emitting device using a light emitting element such as an LED or an LD is a light source having high light conversion efficiency, and is being utilized as a light source that replaces a filament lamp and a fluorescent lamp, due to the small electric power consumption, the long lifetime, and the capability of size reduction thereof. The light emitting device using a light emitting element such as an LED or an LD is being utilized in a wide variety of fields including a lighting system for automobile or indoor use, a backlight source for a liquid crystal display device, a lighting system for an illumination or a projector. In particular, a light emitting device that has a combination of a light emitting element emitting blue light and a yellow fluorescent material, and emits mixed color light thereof has been widely utilized.

    [0004] The known fluorescent materials used in the light emitting device include a rare earth metal aluminate fluorescent material which is an oxide represented by (Y,Gd,Tb,Lu)3(Al,Ga)r)5O12:Ce, a nitride-based fluorescent material represented by CaAlSiN3:Eu, an oxynitride-based fluorescent material such as a β-SiAlON fluorescent material.

    [0005] As the wavelength converting member, for example, a wavelength converting member formed of a sintered body obtained by mixing glass powder and inorganic fluorescent material powder, and melting and solidifying the glass powder is disclosed in Japanese Unexamined Patent Publication No. 2014-234487.

    [0006] However, the wavelength converting member disclosed in Japanese Unexamined Patent Publication No. 2014-234487 may not provide sufficient light emission depending on the type of fluorescent material to be combined with glass powder. The glass component may adversely affect the inorganic fluorescent material during formation of the sintered body, and may cause a remarkable decrease in light conversion efficiency. Also, in the sintered body formed by sintering the glass and the inorganic fluorescent material, it is difficult to obtain a sintered body having high density. In the sintered body formed by sintering the glass and the inorganic fluorescent material, a proportion of voids present in the sintered body is high, and thus the light conversion efficiency decreases when using it in a light emitting device. In addition, when a binder constituting the sintered body to be a wavelength converting member is made of glass having a low melting point, there is a possibility that the glass having a low melting point is melted in the case of irradiating excitation light having high light density, such as a laser light source, and thus the heat resistance is also low. Further, when the inorganic fluorescent material is a fluorescent material containing at least one kind selected from the group consisting of a nitride-based fluorescent material and an oxynitride-based fluorescent material, nitrogen contained in the nitride-based fluorescent material or the oxynitride-based fluorescent material and oxygen contained in an oxide constituting the glass easily reacts. Thus, when the fluorescent material and the glass are calcined, the nitride-based fluorescent material or the oxynitride-based fluorescent material and the glass react, and the fluorescent material is oxidized to change the crystal structure, so that the sintered body obtained after the calcination may not emit light. Further light emitting devices comprising a wavelength conversion member are disclosed in EP 1 670 070.

    [0007] Accordingly, an embodiment of the present invention has an object to provide a wavelength converting member, which is formed of ceramics containing a nitride-based fluorescent material and/or an oxynitride-based fluorescent material, having high light conversion efficiency.

    SUMMARY



    [0008] Means for solving the above problems includes the following embodiments.

    [0009] A first embodiment of the present invention is a wavelength converting member comprising: a fluorescent material containing at least one kind selected from a nitride-based fluorescent material and an oxynitride-based fluorescent material; and an aluminate containing at least one kind selected from the group consisting of a rare earth metal aluminate and an alkaline earth metal aluminate, wherein the content of an activating element selected from Ce, Eu and Mn in the aluminate is less than 50ppm by mass, and the content of the aluminate in the wavelength converting member is 50% by mass or more.

    [0010] A second embodiment of the present invention is a method for producing a wavelength converting member according claim 9, comprising: preparing a molded body obtained by mixing a fluorescent material containing at least one kind selected from a nitride-based fluorescent material and an oxynitride-based fluorescent material and an aluminate containing at least one kind selected from the group consisting of a rare earth metal aluminate and an alkaline earth metal aluminate; and calcining the molded body to obtain a wavelength converting member containing the fluorescent material and the aluminate.

    [0011] In accordance with the embodiments of the present invention, a wavelength converting member, which is formed of ceramics containing a nitride-based fluorescent material and/or an oxynitride-based fluorescent material, having high light conversion efficiency, and a method for producing the same, can be provided.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0012] FIG. 1 is a flowchart showing the process sequence of a method for producing a wavelength converting member according to an embodiment of the present invention.

    DETAILED DESCRIPTION



    [0013] The wavelength converting member and the method for producing the same according to the present invention are described hereunder on the basis of embodiments. The embodiments shown below are exemplifications for exemplifying the technical concept of the present invention, and the present invention is not limited to the methods for producing a wavelength converting member below.
    Standards according to JIS Z8110 are applied to the relations between color names and chromaticity coordinates, the relations between wavelength ranges of light and color names of monochromatic lights.

    Wavelength Converting Member



    [0014] The wavelength converting member according to the first embodiment of the present invention comprises a fluorescent material containing at least one kind selected from the group consisting of a nitride-based fluorescent material and an oxynitride-based fluorescent material, and an aluminate containing at least one kind selected from the group consisting of a rare earth metal aluminate and an alkaline earth metal aluminate.

    [0015] The wavelength converting member according to the first embodiment of the present invention contains, in addition to a nitride-based fluorescent material and/or an oxynitride-based fluorescent material, an aluminate which is hard to react with a nitride and/or an oxynitride as compared with an oxide. Thus, the aluminate serves as a binder, and a wavelength converting member formed of ceramics containing a nitride-based fluorescent material and/or an oxynitride-based fluorescent material can be obtained while maintaining the light conversion efficiency of the nitride-based fluorescent material and/or the oxynitride-based fluorescent material. The wavelength converting member according to the first embodiment of the present invention has high thermal conductivity, since the thermal conductivity of the aluminate functioning as a binder is high. Further, the wavelength converting member according to the first embodiment of the present invention is formed of ceramics, and therefore has high heat resistance.

    Aluminate



    [0016] At least one kind of aluminate selected from the group consisting of a rare earth metal aluminate and an alkaline earth metal aluminate may be used alone, or may be used in combination of two or more kinds thereof. In the case of using two or more kinds of aluminates, two or more kinds of rare earth metal aluminates may be used in combination, two or more kinds of alkaline earth metal aluminates may be used in combination, and one or more kinds of rare earth metal aluminates and one or more kinds of alkaline earth metal aluminates may be used in combination. In the present specification, at least one kind of aluminate selected from the group consisting of a rare earth metal aluminate and an alkaline earth metal aluminate refers to an aluminate not containing an activating element, or an aluminate containing an activating element in a tiny amount, e.g. less than 50 ppm by mass, to the extent not to emit light by excitation light from a light source. In the present specification, at least one kind of aluminate selected from the group consisting of a rare earth metal aluminate and an alkaline earth metal aluminate refers to an aluminate, in which the content of the activating element such as Ce, Eu or Mn is, for example, less than 50 ppm in terms of mass, even in the case of containing the activating element such as Ce, Eu, or Mn. By setting the content of the activating element to such amount, the aluminate can function as a binder for the fluorescent material, but not as the fluorescent material.

    Rare Earth Metal Aluminate



    [0017] The rare earth metal aluminate is preferably at least one kind selected from the group consisting of Y3Al5O12, (Y,Gd)3Al5O12, Y3(Al,Ga)5O12, (Y,Gd)3(Al,Ga)5O12, Tb3Al5O12, and Lu3Al5O12. The rare earth metal aluminate is preferred, since the rare earth metal aluminate is hard to react with a nitride-based fluorescent material or an oxynitride-based fluorescent material, and the crystal structure of the fluorescent material is not decomposed and the rare earth metal aluminate functions as a binder even by sintering together with the fluorescent material, thereby obtaining a sintered body containing the fluorescent material. Among these, the rare earth metal aluminate is preferably Y3Al5O12, since it has high transparency, hardly reacts with a nitride or an oxynitride, and is inexpensive and easily available. In the compositional formula expressing a compound in the present specification, plural elements delimited with commas (,) mean that at least one kind of the plural elements is contained in the composition of the compound. The plural elements delimited with commas (,) in the compositional formula expressing a compound mean that the composition contains at least one kind of element selected from the plural elements delimited with commas in the compositional formula, and may contain a combination of two or more kinds of the plural elements. In this context, the term "plural" is used to refer to two or more elements.

    Alkaline Earth Metal Aluminate



    [0018] The alkaline earth metal aluminate is preferably at least one kind selected from the group consisting of (Ca,Sr,Ba)Al2O4, (Ca,Sr,Ba)1Al14O25, (Ca,Sr,Ba)Al12O19, (Ca,Sr,Ba)Mg2Al16O27 and (Ca,Sr,Ba)MgAl10O17. The alkaline earth metal aluminate represented by (Ca,Sr,Ba)Al2O)4, (Ca,Sr,Ba)4Al14O25, (Ca,Sr,Ba)Al12O19, (Ca,Sr,Ba)Mg2Al16O27, or (Ca,Sr,Ba)MgAl10O17 may contain at least one kind of alkaline earth metal element selected from the group consisting of Ca, Sr, and Ba, and may contain two or more kinds of alkaline earth metal elements selected from the group consisting of Ca, Sr, and Ba in the aluminate. The alkaline earth metal aluminate is preferred, since the alkaline earth metal aluminate hardly reacts with a nitride-based fluorescent material and/or an oxynitride-based fluorescent material, and the crystal structure of the fluorescent material is not decomposed and the alkaline earth metal aluminate functions as a binder even by sintering together with the fluorescent material, thereby obtaining a sintered body containing the fluorescent material.

    Nitride-Based Fluorescent Material



    [0019] The nitride-based fluorescent material is preferably at least one kind selected from the group consisting of (Ca,Sr,Ba)AlSiN3:Eu, (Ca,Sr,Ba)AlSiN3:Ce, (Ca,Sr,Ba)2Si5N8:Eu, SrLiAl3N4:Eu, La3Si6N11:Ce, CaAlSiN3:Eu, CaAlSiN3:Ce, (Ca,Sr)AlSiN3:Eu, (Ca,Sr)AlSiN3:Ce, Ca2Si5N8:Eu, and (Ca,Sr)2Si5N8:Eu. Among these, the nitride-based fluorescent material is preferably CaAlSiN3:Eu, since a desired color tone can be easily obtained and it is easily available. It is preferred that the wavelength converting member contains CaAlSiN3:Eu as a fluorescent material and Y3Al5O12 as a rare earth metal aluminate, since a desired red color tone can be easily obtained and these are easily available.

    [0020] The nitride-based fluorescent material absorbs light emitted from an excitation light source having a light emission peak wavelength in a range of 380 nm or more and 485 nm or less, and emits red light having a light emission peak wavelength in a range of 590 nm or more and 780 nm or less. However, even if it is the same nitride-based fluorescent material, La3Si6N11:Ce emits yellow-green light having a light emission peak in the vicinity of 530 nm. The nitride-based fluorescent material in the wavelength converting member is hard to react with the aluminate functioning as a binder, and the crystal structure is not decomposed. Thus, the nitride-based fluorescent material can absorb light emitted from an excitation light source, and can emit fluorescent color light having a light emission peak in a desired wavelength range. It should be noted that nitride-based fluorescent materials are preferred over oxynitride-based fluorescent materials.

    Oxynitride-Based Fluorescent Material



    [0021] The oxynitride-based fluorescent material is preferably at least one kind selected from the group consisting of: BaSi2O2N2:Eu; Ba3Si6O12N2:Eu; Mm/2Si12-(m+n)Al(m+n)OnN(16-n):Eu wherein M represents at least one kind of element selected from the group consisting of Sr, Ca, Li, and Y, parameters n and m satisfy 0.0 ≤ n ≤ 2.5 and 0.5 ≤ m ≤ 5 respectively, and the parameter n is an electric charge of M; and Si6-zAlzOzN8-z: wherein parameter z satisfies 0 < z < 4.2. The oxynitride-based fluorescent material absorbs light emitted from an excitation light source having a light emission peak wavelength in a range of 380 nm or more and 485 nm or less, and emits light from blue-green to red-orange, which has a light emission peak wavelength in a range of 470 nm or more and 620 nm or less, depending on a type of the oxynitride-based fluorescent material. The oxynitride-based fluorescent material in the wavelength converting member hardly reacts with the aluminate functioning as a binder, and the crystal structure is not decomposed. Thus, the oxynitride-based fluorescent material can absorb light emitted from an excitation light source, and can emit fluorescent color light having a light emission peak in a desired wavelength range.

    [0022] At least one kind of fluorescent material selected from the group consisting of a nitride-based fluorescent material and an oxynitride-based fluorescent material may be used alone, or may be used in combination of two or more kinds thereof as long as emission of fluorescent color light having a desired color tone can be obtained by excitation light. In the case of using two or more kinds of fluorescent materials, two or more kinds of nitride-based fluorescent materials may be used in combination, two or more kinds of oxynitride-based fluorescent materials may be used in combination, and one or more kinds of nitride-based fluorescent materials and one or more kinds of oxynitride-based fluorescent materials may be used in combination.

    Other Fluorescent Material



    [0023] The wavelength converting member may further contain a fluorescent material other than the nitride-based fluorescent material and the oxynitride-based fluorescent material. The fluorescent material other than the nitride-based fluorescent material and the oxynitride-based fluorescent material, which is contained in the wavelength converting member, is preferably a fluorescent material having a composition of an aluminate. The fluorescent material having a composition of an aluminate is preferably at least one kind selected from the group consisting of a rare earth metal aluminate fluorescent material and an alkaline earth metal aluminate fluorescent material. The fluorescent material having a composition of an aluminate also functions as a binder in the same manner as the aluminate constituting a binder in the wavelength converting member. As long as the wavelength converting member can provide a fluorescent color having a desired color tone, the fluorescent material having a composition of an aluminate may be used as a binder instead of the aluminate not containing an activating element or the aluminate containing an activating element in an amount of less than 50 ppm in terms of mass.

    [0024] It is preferred that the wavelength converting member further comprises at least one kind of rare earth metal aluminate fluorescent material selected from the group consisting of Y3Al5O12:Ce, (Y,Gd)3Al5O12:Ce, Y3(Al,Ga)5O12:Ce, (Y,Gd)3(Al,Ga)5O12:Ce, Tb3Al5O12:Ce, and Lu3Al5O12:Ce. In each of the rare earth metal aluminate fluorescent materials, a part of the composition of the aluminate not containing an activating element such as Ce or the aluminate in which the content of the activating element is less than 50 ppm in terms of mass is replaced with the activating element such as Ce. The rare earth metal aluminate fluorescent material containing an activating element can also be utilized as a binder in the wavelength converting member in the same manner as the aluminate that does not emit light by excitation light, such as the aluminate in which the content of the activating element is less than 50 ppm in terms of mass. The rare earth metal aluminate fluorescent material can be distinguished from the rare earth metal aluminate used as the binder in that the total amount of activating elements in the rare earth metal aluminate fluorescent material is 50 ppm by mass or more, while the total amount of activating elements in the rare earth metal aluminate used as the binder is less than 50 ppm by mass.

    [0025] It is preferred that the wavelength converting member further comprises at least one kind of alkaline earth metal aluminate fluorescent material selected from the group consisting of SrAl2O4:Eu, Sr4Al14O25:Eu, BaMg2Al16O27:Eu, BaMgAl10O17:Mn, BaMgAl10O17:Eu, Sr4Al14O25:Eu,Mn, CaAl2O4:Eu,Mn, BaMg2Al16O27:Eu,Mn, and BaMgAl10O17:Eu,Mn. In the alkaline earth metal aluminate fluorescent material represented by each of the compositions, a part of the composition of the alkaline earth metal aluminate not containing an activating element constituting a binder in the wavelength converting member or the alkaline earth metal aluminate in which the content of an activating element is less than 50 ppm in terms of mass is replaced with activating elements such as Eu, Mn, or Eu and Mn. The alkaline earth metal aluminate fluorescent material can be distinguished from the alkaline earth metal aluminate used as the binder in that the total amount of activating elements in the alkaline earth metal aluminate fluorescent material is 50 ppm by mass or more, while the total amount of activating elements in the alkaline earth metal aluminate used as the binder is less than 50 ppm by mass.

    [0026] The alkaline earth metal aluminate fluorescent material containing an activating element can also be utilized as a binder in the wavelength converting member in the same manner as the alkaline earth metal aluminate in which the content of an activating element is less than 50 ppm in terms of mass.

    [0027] At least one kind of fluorescent material selected from the group consisting of a rare earth metal aluminate fluorescent material and an alkaline earth metal aluminate fluorescent material may be used alone, or may be used in combination of two or more kinds thereof as long as emission of fluorescent color light having a desired color tone can be obtained by excitation light. In the case of using two or more kinds of fluorescent materials, two or more kinds of rare earth metal aluminate fluorescent materials may be used in combination, two or more kinds of alkaline earth metal aluminate fluorescent materials may be used in combination, and one or more kinds of rare earth metal aluminate fluorescent materials and one or more kinds of alkaline earth metal aluminate fluorescent materials may be used in combination.

    Method for Producing Wavelength Converting Member



    [0028] The method of producing a wavelength converting member according to the second embodiment of the present invention comprises: preparing a molded body obtained by mixing a fluorescent material containing at least one kind selected from the group consisting of a nitride-based fluorescent material and an oxynitride-based fluorescent material and an aluminate containing at least one kind selected from the group consisting of a rare earth metal aluminate and an alkaline earth metal aluminate; and sintering the molded body to obtain a wavelength converting member containing the fluorescent material and the aluminate.

    [0029] In accordance with the production method according to the second embodiment of the present invention, the wavelength converting member is formed of a sintered body obtained by sintering a molded body containing: a fluorescent material containing at least one kind selected from a nitride-based fluorescent material and an oxynitride-based fluorescent material; and an aluminate containing at least one kind selected from the group consisting of a rare earth metal aluminate and an alkaline earth metal aluminate. Thus, a wavelength converting member formed of ceramics containing an aluminate functioning as a binder and a nitride-based fluorescent material and/or an oxynitride-based fluorescent material can be obtained while maintaining the light conversion efficiency of the nitride-based fluorescent material and/or the oxynitride-based fluorescent material. The wavelength converting member obtained by the production method according to the second embodiment of the present invention has high thermal conductivity, since the thermal conductivity of the aluminate functioning as a binder in the wavelength converting member is high. Further, the wavelength converting member obtained by the production method according to the second embodiment of the present invention is formed of ceramics, and therefore has high heat resistance.

    Aluminate



    [0030] Specifically, at least one kind of the aforementioned aluminate can be used as an aluminate.

    [0031] The charge-in amount of the aluminate is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 65% by mass or more, relative to 100% by mass of the total amount of mixed powder obtained by mixing the aluminate and the fluorescent material containing at least one kind selected from the group consisting of a nitride-based fluorescent material and an oxynitride-based fluorescent material. Further, the content of the aluminate in the wavelength converting member is the same as the mass ratio of the aluminate powder relative to 100% by mass of the total amount by mass of the mixed powder obtained by mixing the aluminate powder and the fluorescent material powder. When the content of the aluminate contained in the wavelength converting member is 50% by mass or more relative to 100% by mass of the total amount of the mixed powder obtained by mixing the aluminate and the fluorescent material, a sintered body, which contains the aluminate functioning as a binder without hindering light emission of a nitride-based fluorescent material or an oxynitride-based fluorescent material having a light emission peak wavelength within a desired wavelength range, can be obtained. The content of the aluminate may be more than 99% by mass relative to 100% by mass of the total amount of the mixed powder obtained by mixing the aluminate powder and the fluorescent material powder, but the content of the fluorescent material contained in the wavelength converting member becomes relatively low. Thus, the content of the aluminate is preferably 99% by mass or less in order to provide emission of fluorescent color light having a desired color tone by excitation light emitted from a light source.

    Average Particle Diameter of Aluminate



    [0032] The average particle diameter of the aluminate is preferably in a range of 1 µm or more and 25 µm or less, more preferably in a range of 2 µm or more and 20 µm or less, even more preferably in a range of 2 µm or more and 18 µm or less. When the average particle diameter of the aluminate powder before constituting the wavelength converting member falls within the aforementioned range, a molded body can be formed by substantially uniformly mixing the aluminate and the fluorescent material, and a wavelength converting member, in which the fluorescent material is uniformly present in the wavelength converting member to be obtained, capable of uniformly emitting light can be obtained. When the average particle diameter of the aluminate powder is 25 µm or less, voids in the wavelength converting member are decreased, and thus the light conversion efficiency can be enhanced. In the present specification, the average particle diameter of the aluminate powder refers to an average particle diameter (Fisher Sub-Sieve Sizer's number) measured by a Fisher Sub-Sieve Sizer (FSSS) method. The FSSS method is a type of an air permeability method for measuring a specific surface area by utilizing the flow resistance of air to determine a particle diameter.

    Content of Nitride-Based Fluorescent Material and/or Oxynitride-Based Fluorescent Material



    [0033] Specifically, at least one kind of the fluorescent material selected from the group consisting of the aforementioned nitride-based fluorescent material and the oxynitride-based fluorescent material can be used as at least one kind of fluorescent material selected from the group consisting of a nitride-based fluorescent material and an oxynitride-based fluorescent material.

    [0034] The content of at least one kind of the fluorescent material selected from the group consisting of a nitride-based fluorescent material and an oxynitride-based fluorescent material is preferably in a range of 1% by mass or more and 50% by mass or less, more preferably in a range of 2% by mass or more and 20% by mass or less, even more preferably 3% by mass or more and 18% by mass or less, relative to 100% by mass of the total amount by mass of mixed powder of the fluorescent material and the aluminate. The content of the nitride-based fluorescent material and/or the oxynitride-based fluorescent material in the wavelength converting member is the same as the mass ratio of the powder of the nitride-based fluorescent material and/or the oxynitride-based fluorescent material relative to 100% by mass of the total amount by mass of the mixed powder obtained by mixing the aluminate powder and the fluorescent material powder. The content of the nitride-based fluorescent material and/or the oxynitride-based fluorescent material in the wavelength converting member is not particularly limited as long as emission of fluorescent color light having a light emission peak in a desired wavelength range can be obtained by absorbing light from an excitation light source.

    Content of Other Fluorescent Material



    [0035] Specifically, in the case of containing at least one kind of the fluorescent material selected from the group consisting of the aforementioned rare earth metal aluminate fluorescent material and the alkaline earth metal aluminate fluorescent material in addition to at least one kind of the fluorescent material selected from the group consisting of a nitride-based fluorescent material and an oxynitride-based fluorescent material, at least one kind selected from the group consisting of the aforementioned rare earth metal aluminate fluorescent material and the alkaline earth metal aluminate fluorescent material is preferably contained.

    [0036] The content of at least one kind of the aluminate fluorescent material selected from the group consisting of a rare earth metal aluminate fluorescent material and an alkaline earth metal aluminate fluorescent material is not particularly limited as long as emission of fluorescent color light having a desired color tone can be obtained. At least one kind of the aluminate fluorescent material selected from the group consisting of a rare earth metal aluminate fluorescent material and an alkaline earth metal aluminate fluorescent material may not be contained in the wavelength converting member, and the content of the aluminate fluorescent material may be 0% by mass relative to 100% by mass of the total amount of the mixed powder obtained by mixing the fluorescent material powder and the aluminate powder. The content of the rare earth metal aluminate fluorescent material and/or the alkaline earth metal aluminate fluorescent material in the wavelength converting member is the same as the mass ratio of the powder of the rare earth metal aluminate fluorescent material and/or the alkaline earth metal aluminate fluorescent material relative to 100% by mass of the total amount by mass of the mixed powder obtained by mixing the aluminate powder and the fluorescent material powder. As long as the wavelength converting member can provide emission of fluorescent color light having a desired color tone, the content of the aluminate fluorescent material is preferably 50% by mass or less, more preferably in a range of 1% by mass or more and 20% by mass or less, even more preferably in a range of 1% by mass or more and 18% by mass or less, relative to 100% by mass of the total amount by mass of the mixed powder obtained by mixing the aluminate powder and the fluorescent material powder.

    Average Particle Diameter of Fluorescent Material



    [0037] The average particle diameter of the fluorescent material is preferably in a range of 1 µm or more and 25 µm or less, more preferably in a range of 2 µm or more and 20 µm or less, even more preferably in a range of 2 µm or more and 15 µm or less. When the average particle diameter of the fluorescent material is 1 µm or more, the aluminate powder and the fluorescent material powder are substantially uniformly dispersed, and a wavelength converting member, in which the fluorescent material is uniformly present, capable of uniformly emitting light can be obtained. When the average particle diameter of the fluorescent material is 25 µm or less, voids in the wavelength converting member are reduced, and thus high light conversion efficiency can be maintained in the fluorescent material. The fluorescent material is at least one kind of fluorescent material selected from the group consisting of a nitride-based fluorescent material, an oxynitride-based fluorescent material, a rare earth metal aluminate fluorescent material, and an alkaline earth metal aluminate fluorescent material. In the present specification, the average particle diameter of the fluorescent material refers to an average particle diameter (Fisher Sub-Sieve Sizer's number) measured by a Fisher Sub-Sieve Sizer (FSSS) method.

    [0038] FIG. 1 is a flowchart showing an illustration of the order of steps in the method for producing a wavelength converting member according to the second embodiment. The steps in the method for producing a wavelength converting member will be described with reference to FIG. 1. The method for producing a wavelength converting member includes Step S102 of preparing a molded body and Step S103 of sintering. The method for producing a wavelength converting member may include Step S101 of mixing powder before Step S102 of preparing the molded body, and may include Step S104 of processing the wavelength converting member after Step S013 of sintering.

    Step of Mixing Powder



    [0039] In the step of mixing powder, fluorescent material powder containing at least one kind selected from the group consisting of a nitride-based fluorescent material and an oxynitride-based fluorescent material; and aluminate powder containing at least one kind selected from the group consisting of a rare earth metal aluminate and an alkaline earth metal aluminate are mixed to obtain mixed powder. The powders can be mixed by using a mortar and a pestle. The powders can also be mixed by using a mixing medium such as in the case of a ball mill.

    Step of Preparing the Molded Body



    [0040] In the step of preparing the molded body, the mixed powder containing the fluorescent material powder and the aluminate powder is molded into a desired shape to obtain a molded body. The method employed for molding the powder may be a known method such as a press molding method, and examples thereof may include a mold pressing method and a cold isostatic pressing (hereinafter also referred to as "CIP") method. For conditioning the shape of the molded body, two or more kinds of molding methods may be employed, and the CIP may be performed after performing the mold pressing.

    Step of Sintering



    [0041] In the step of sintering, the sintering is preferably performed according to a solid compression sintering method. Examples of the solid compression sintering method may include a hot isostatic pressing (HIP) treatment (hereinafter also referred to as "HIP treatment") and a spark plasma sintering method (also referred to as "SPS method"). By using any of the solid compression sintering methods, voids in the wavelength converting member formed of the sintered body to be obtained are decreased, and the density is increased, so that the light conversion efficiency can be enhanced.

    [0042] In the case of performing the sintering according to the SPS method, by effectively applying electro-diffusion, in which pulse-like electric energy is directly charged to voids between particles of the molded body, and high energy of high temperature plasma (spark plasma) instantly generated by spark discharge is thermally diffused, the sintered body can be obtained in a short time.

    Step of Processing Step



    [0043] The method of producing a wavelength converting member may include a step of processing for processing the wavelength converting member formed of the resulting sintered body. Examples of the step of processing may include a step of cutting the resulting wavelength converting member into a desired size. The cutting method used for the wavelength converting member may be a known method, and examples thereof may include blade dicing, laser dicing, and wire sawing.

    [0044] In combination with a light emitting element such as an LED or an LD, the wavelength converting member according to the first embodiment or the wavelength converting member obtained by the production method according to the second embodiment converts light emitted from the light emitting element and can constitute a light emitting device that emits mixed light of light from the light emitting element and light that has undergone wavelength conversion by the wavelength converting member. For example, a light emitting element that emits light in a wavelength range of 350 nm or more and 500 nm or less can be used as the light emitting element. For example, a semiconductor light emitting element using a nitride-based semiconductor (InXAlYGa1-X-YN, 0 ≤ X, 0 ≤ Y, X+Y ≤ 1) can be used as the light emitting element. The use of the semiconductor light emitting device as an excitation light source may provide a stable light emitting device that has high efficiency, high linearity of the output relative to the input, and high strength against a mechanical impact.

    EXAMPLES



    [0045] The present invention is hereunder specifically described by reference to the following Examples. The present invention is not limited to these Examples.

    Example 1


    Step of Mixing Powder



    [0046] 17 g of Y3Al5O12 (also referred to as "YAG") crystalline powder having an average particle diameter of 3 µm and 1.5 g of CaAlSiN3:Eu (hereinafter also referred to as "CASN") fluorescent material powder having an average particle diameter of 7 µm were weighed and mixed by using a mortar and a pestle to prepare mixed powder for forming a molded body. As for the YAG powder used in each of Examples 1 to 3, the content of the activating element (for example, Eu or the like) was less than 50 ppm in terms of mass. Relative to 100% by mass of the total amount of the YAG powder and the CASN fluorescent material powder, the content of the YAG powder was 91.9% by mass, and the content of the CASN fluorescent material powder was 8.1% by mass.

    Step of Preparing of Molded Body



    [0047] The mixed powder was filled into a mold to temporarily form a cylindrical molded body having a diameter of 25 mm and a thickness of 6 mm.

    Step of Sintering



    [0048] The resulting molded body was subjected to sintering according to the HIP treatment with an HIP device (manufactured by Kobe Steel, Ltd.) using nitrogen gas as a pressure medium in a nitrogen gas atmosphere (nitrogen: 99% by volume or more) at 1,700°C and 150 MPa for 10 hours to obtain a sintered body.

    Step of Processing



    [0049] The resulting sintered body was sliced with a wire saw, and ground and divided into individual pieces with a polishing device or a blade dicing, thereby obtaining a rectangular wavelength converting member having a size of 1 mm × 1 mm and a thickness of 0.2 mm.

    Example 2



    [0050] A wavelength converting member was obtained in the same manner as in Example 1 except that a mixed powder obtained by mixing 17 g of the YAG crystalline powder having an average particle diameter of 3 µm and 3 g of the CASN fluorescent material powder having an average particle diameter of 7 µm was prepared. In the sintered body to be the wavelength converting member of Example 2, the content of the YAG powder was 85% by mass, and the content of the CASN fluorescent material powder was 15% by mass, relative to 100% by mass of the total amount of the YAG powder and the CASN fluorescent material powder.

    Example 3



    [0051] A wavelength converting member was obtained in the same manner as in Example 1 except that a mixed powder obtained by mixing 15.5 g of the YAG crystalline powder having an average particle diameter of 3 µm, 1.0 g of the CASN fluorescent material powder having an average particle diameter of 7 µm, and 3.5 g of Lu3Al5O12:Ce (hereinafter also referred to as "LuAG:Ce") fluorescent material powder having an average particle diameter of 10 µm was prepared. In the sintered body to be the wavelength converting member of Example 3, the content of the YAG powder was 77.5% by mass, the content of the CASN fluorescent material powder was 5% by mass, and the content of the LuAG:Ce fluorescent material powder was 17.5% by mass, relative to 100% by mass of the total amount of the YAG powder, the CASN fluorescent material powder, and the LuAG:Ce fluorescent material powder.

    Example 4



    [0052] A wavelength converting member was obtained in the same manner as in Example 1 except that a mixed powder obtained by mixing 15.5 g of Sr4Al14O25 (hereinafter also referred to as "SAE") crystalline powder having an average particle diameter of 3 µm, 1.0 g of the CASN fluorescent material powder having an average particle diameter of 7 µm, and 3.5 g of LuAG:Ce fluorescent material powder having an average particle diameter of 10 µm was prepared. As for the SAE powder, the content of the activating element (for example Eu) was less than 50 ppm in terms of mass. In the sintered body to be the wavelength converting member of Example 4, the content of the SAE powder was 77.5% by mass, the content of the CASN fluorescent material powder was 5% by mass, and the content of the LuAG:Ce fluorescent material powder was 17.5% by mass, relative to 100% by mass of the total amount of the SAE powder, the CASN fluorescent material powder, and the LuAG:Ce fluorescent material powder.

    Example 5



    [0053] A wavelength converting member was obtained in the same manner as in Example 1 except that a mixed powder obtained by mixing 15.5 g of BaMgAl10O17 (hereinafter also referred to as "BAM") crystalline powder having an average particle diameter of 3 µm, 1.0 g of the CASN fluorescent material powder having an average particle diameter of 7 µm, and 3.5 g of LuAG:Ce fluorescent material powder having an average particle diameter of 10 µm was prepared. As for the BAM powder, the content of the activating element (for example Eu) was less than 50 ppm in terms of mass. In the sintered body to be the wavelength converting member of Example 5, the content of the BAM powder was 77.5% by mass, the content of the CASN fluorescent material powder was 5% by mass, and the content of the LuAG:Ce fluorescent material powder was 17.5% by mass, relative to 100% by mass of the total amount of the BAM powder, the CASN fluorescent material powder, and the LuAG:Ce fluorescent material powder.

    Comparative Example 1



    [0054] A rectangular sintered body sample having a size of 1 mm × 1 mm and a thickness of 0.2 mm was obtained in the same manner as in Example 1 except that a mixed powder obtained by mixing 17 g of borosilicate glass powder and 3 g of the CASN fluorescent material powder having an average particle diameter of 7 µm was prepared. In the sintered body, the content of the borosilicate glass powder was 85% by mass, and the content of the CASN fluorescent material powder was 15% by mass, relative to 100% by mass of the total amount of the borosilicate glass powder and the CASN fluorescent material powder.

    Comparative Example 2



    [0055] A rectangular sintered body sample having a size of 1 mm × 1 mm and a thickness of 0.2 mm was obtained in the same manner as in Example 1 except that a mixed powder obtained by mixing 17 g of α-alumina powder having an average particle diameter of 0.5 µm and 3 g of the CASN fluorescent material powder having an average particle diameter of 7 µm was prepared. In the sintered body, the content of the α-alumina powder was 85% by mass, and the content of the CASN fluorescent material powder was 15% by mass, relative to 100% by mass of the total amount of the α-alumina powder and the CASN fluorescent material powder.

    Average Particle Diameter by FSSS method



    [0056] As for the YAG, the SAE, the BAM, the CASN fluorescent material, and the LuAG:Ce fluorescent material used in each of Examples and Comparative Examples, the average particle diameter (Fisher Sub-Sieve Sizer's Number) (µm) was measured using a Fisher Sub-Sieve Sizer Model 95 (manufactured by Fisher Scientific Inc.) according to the FSSS method.

    Light Emitting Device



    [0057] Each of the wavelength converting members according to Examples 1 to 5 and the sintered body samples according to Comparative Examples 1 to 2 was mounted on a blue light emitting LED (light emitting element) having a light emission peak wavelength of 455 nm to obtain a light emitting device. As for the light emitting devices according to Comparative Examples 1 and 2, no fluorescent light was emitted even when a current of 1 A was made to flow through the blue light emitting LED to irradiate excitation light.

    Chromaticity Coordinates (x, y) Value and General Color Rendering Index Ra



    [0058] The chromaticity coordinates (x, y) of Commission international de l'eclairage (CIE) 1931 color system and the general color rendering index Ra were measured by using a multichannel spectroscope (product name: PMA-12, manufactured by Hamamatsu Photonics K.K.) when a current of 1 A was made to flow through each of the light emitting devices using the wavelength converting members according to Examples 1 to 5. The results are shown in Table 1.

    Relative Luminous Flux Ratio



    [0059] The luminous flux (lm) was measured by using a total luminous flux measuring device with an integrating sphere when a current of 1 A was made to flow through each of the light emitting devices using the wavelength converting members according to Examples 1 to 5, and the relative luminous flux ratio (%) was calculated when the luminous flux of the light emitting device using the wavelength converting member of Examples 1 was used as a basis (100%). The results are shown in Table 1.
    Table 1
     Aluminate etc.Nitride-based fluorescent materialAluminate fluorescent materialEvaluation of wavelength converting member
    TypePowder mixed amount (g)Content (% by mass)TypePowder mixed amount (g)Content (% by mass)TypePowder mixed amount (g)Content (% by mass)Chromaticity coordinatesGeneral color rendering index RaRelative luminous flux ratio (%)
    xy
    Example 1 YAG 17.0 91.9 CASN 1.5 8.1 - - - 0.42 0.15 - 100
    Example 2 YAG 17.0 85.0 CASN 3.0 15.0 - - - 0.63 0.28 - 136
    Example 3 YAG 15.5 77.5 CASN 1.0 5.0 LuAG:Ce 3.5 17.5 0.37 0.36 88 200
    Example 4 SAE 15.5 77.5 CASN 1.0 5.0 LuAG:Ce 3.5 17.5 0.32 0.33 90 171
    Example 5 BAM 15.5 77.5 CASN 1.0 5.0 LuAG:Ce 3.5 17.5 0.39 0.38 86 164
    Comparative Example 1 Glass 17.0 85.0 CASN 3.0 15.0 - - - No light emission
    Comparative Example 2 α-alumina 17.0 85.0 CASN 3.0 15.0 - - - No light emission


    [0060] As shown in Table 1, the wavelength converting member of Example 1 emitted pink light by the excitation light emitted from the blue LED having a light emission peak wavelength of 455 nm. The wavelength converting member of Example 2 emitted red light by the excitation light emitted from the blue LED having a light emission peak wavelength of 455 nm, and had a relative luminous flux ratio higher than that of the light emitting device in Example 1.

    [0061] As shown in Table 1, all of the wavelength converting members of Examples 3 to 5 emitted white light, and had a general color rendering index Ra of 85 or more. Particularly, in Example 3, a wavelength converting member having high color rendering and a high relative luminous flux ratio was obtained.

    [0062] On the other hand, as shown in Table 1, the sintered body sample of each of Comparative Examples 1 to 2 did not emit fluorescence even by irradiating with the excitation light emitted from the blue LED having a light emission peak wavelength of 455 nm. Accordingly, it was presumed that the CASN fluorescent material in the sintered body had reacted with the borosilicate glass or the α-alumina during the calcination, and the CASN fluorescent material was oxidized and decomposed.

    [0063] The wavelength converting member according to the first embodiment of the present invention and the wavelength converting member obtained by the production method according to the second embodiment of the present invention have high light conversion efficiency, can emit light with a desired color tone, and can be utilized as a wavelength converting member having high light conversion efficiency with respect to the wavelength of light emitted from an LED or an LD.


    Claims

    1. A wavelength converting member, comprising:

    a fluorescent material containing at least one kind selected from the group consisting of a nitride-based fluorescent material and an oxynitride-based fluorescent material; and

    an aluminate containing at least one kind selected from the group consisting of a rare earth metal aluminate and an alkaline earth metal aluminate, wherein the content of an activating element selected from Ce, Eu and Mn in the aluminate is less than 50 ppm by mass, and

    the content of the aluminate in the wavelength converting member is 50% by mass or more.


     
    2. The wavelength converting member according to claim 1, wherein the rare earth metal aluminate is at least one kind selected from the group consisting of Y3Al5O12, (Y,Gd)3Al5O12, Y3(Al,Ga)5O12, (Y,Gd)3(Al,Ga)5O12, Tb3Al5O12, and Lu3Al5O12.
     
    3. The wavelength converting member according to claim 1, wherein the alkaline earth metal aluminate is at least one kind selected from the group consisting of (Ca,Sr,Ba)Al2O4, (Ca,Sr,Ba)4Al4O25, (Ca,Sr,Ba)Al12O19, (Ca,Sr,Ba)Mg2Al16O27, and (Ca,Sr,Ba)MgAl10O17.
     
    4. The wavelength converting member according to any one of claims 1 to 3, wherein the nitride-based fluorescent material is at least one kind selected from the group consisting of (Ca,Sr,Ba)AlSiN3:Eu, (Ca,Sr,Ba)AlSiN3:Ce, (Ca,Sr,Ba)2Si5N8:Eu, SrLiAl3N4:Eu, and La3Si6N11:Ce, CaAlSiN3:Eu, CaAlSiN3:Ce, (Ca,Sr)AlSiN3:Eu, (Ca,Sr)AlSiN3:Ce, Ca2Si5N8:Eu, and (Ca,Sr)2Si5N8:Eu.
     
    5. The wavelength converting member according to any one of claims 1 to 3, wherein the oxynitride-based fluorescent material is at least one kind selected from the group consisting of: BaSi2O2N2:Eu; Ba3Si6O12N2:Eu; Mm/2Si12-(m+n)Al(m+n)OnN(16-n):Eu wherein M represents at least one kind of element selected from the group consisting of Sr, Ca, Li, and Y, parameters n and m satisfy 0.0 ≤ n ≤ 2.5 and 0.5 ≤ m ≤ 5 respectively, and the parameter n is an electric charge of M; and Si6-zAlzOzN8-z:Eu wherein parameter z satisfies 0 < z < 4.2.
     
    6. The wavelength converting member according to any one of claims 1 to 5, wherein the fluorescent material further comprises at least one kind of rare earth metal aluminate fluorescent material selected from the group consisting of Y3Al5O12:Ce, (Y,Gd)3Al5O12:Ce, Y3(Al,Ga)5O12:Ce, (Y,Gd)3(Al,Ga)5O12:Ce, Tb3Al5O12:Ce, and Lu3Al5O12:Ce, Sr4Al14O25:Eu,Mn, CaAl2O4:Eu,Mn, BaMg2Al16O27:Eu,Mn, and BaMgAl10O17:Eu,Mn.
     
    7. The wavelength converting member according to any one of claims 1 to 6, wherein the fluorescent material further comprises at least one kind of alkaline earth metal aluminate fluorescent material selected from the group consisting of SrAl2O4:Eu, Sr4Al14O25:Eu, BaMg2Al16O27:Eu, BaMgAl10O17:Mn, and BaMgAl10O17:Eu.
     
    8. The wavelength converting member according to any one of claims 1, 2, 4, 6, and 7, wherein the nitride-based fluorescent material is CaAlSiN3:Eu, and the rare earth metal aluminate is Y3Al5O12.
     
    9. A method for producing a wavelength converting member, comprising:

    preparing a molded body obtained by mixing a fluorescent material containing at least one kind selected from the group consisting of a nitride-based fluorescent material and an oxynitride-based fluorescent material and an aluminate containing at least one kind selected from the group consisting of a rare earth metal aluminate and an alkaline earth metal aluminate; and

    sintering the molded body to obtain a wavelength converting member containing the fluorescent material and the aluminate, wherein the content of an activating element selected from Ce, Eu and Mn in the aluminate is less than 50 ppm by mass, and

    the content of the aluminate in the wavelength converting member is 50% by mass or more.


     
    10. The method for producing a wavelength converting member according to claim 9, wherein the calcination is performed according to a solid compression sintering method.
     
    11. The method for producing a wavelength converting member according to claim 9 or 10, wherein the average particle diameter of the aluminate is in a range of 1 µm or more and 25 µm or less.
     
    12. The method for producing a wavelength converting member according to any one of claims 9 to 11, wherein the average particle diameter of the fluorescent material is in a range of 1 µm or more and 25 µm or less.
     
    13. The method for producing a wavelength converting member according to any one of claims 9 to 12, wherein the nitride-based fluorescent material is CaAlSiN3:Eu, and the rare earth metal aluminate is Y3Al5O12.
     


    Ansprüche

    1. Ein Wellenlängenumwandlungselement, umfassend:

    ein fluoreszierendes Material, das mindestens Eines, ausgewählt aus der Gruppe bestehend aus einem fluoreszierenden Material auf der Basis von Nitrid und einem fluoreszierenden Material auf der Basis von Oxynitrid, enthält; und

    ein Aluminat, das mindestens Eines, ausgewählt aus der Gruppe bestehend aus einem Seltenerdmetallaluminat und einem Erdalkalimetallaluminat enthält, wobei der Gehalt eines aktivierenden Elements, ausgewählt aus Ce, Eu und Mn, in dem Aluminat weniger als 50 Massen-ppm beträgt und

    wobei der Gehalt des Aluminats in dem Wellenlängenumwandlungselement 50 Massen-% oder mehr beträgt.


     
    2. Das Wellenlängenumwandlungselement gemäß Anspruch 1, wobei das Seltenerdmetallaluminat mindestens Eines, ausgewählt aus der Gruppe bestehend aus Y3Al5O12, (Y,Gd)3Al5O12, Y3(Al,Ga)5O12, (Y,Gd)3(Al,Ga)5O12, Tb3Al5O12 und Lu3Al5O12, ist.
     
    3. Das Wellenlängenumwandlungselement gemäß Anspruch 1, wobei das Erdalkalimetallaluminat mindestens Eines, ausgewählt aus der Gruppe bestehend aus (Ca,Sr,Ba)Al2O4, (Ca,Sr,Ba)4Al14O25, (Ca,Sr,Ba)Al12O19, (Ca,Sr,Ba)Mg2Al16O27 und (Ca,Sr,Ba)MgAl10O17, ist.
     
    4. Das Wellenlängenumwandlungselement gemäß einem der Ansprüche 1 bis 3, wobei das fluoreszierende Material auf der Basis von Nitrid mindestens Eines, ausgewählt aus der Gruppe bestehend aus (Ca,Sr,Ba)AlSiN3:Eu, (Ca,Sr,Ba)AlSiN3:Ce, (Ca,Sr,Ba)2Si5N8:Eu, SrLiAl3N4:Eu und La3Si6N11:Ce, CaAlSiN3:Eu, CaAlSiN3:Ce, (Ca,Sr)AlSiN3:Eu, (Ca,Sr)AlSiN3:Ce, Ca2Si5N8:Eu und (Ca,Sr)2Si5N8:Eu, ist.
     
    5. Das Wellenlängenumwandlungselement gemäß einem der Ansprüche 1 bis 3, wobei das fluoreszierende Material auf der Basis von Oxynitrid mindestens Eines, ausgewählt aus der Gruppe bestehend aus: BaSi2O2N2:Eu; Ba3Si6O12N2:Eu; Mm/2Si12-(m+n)Al(m+n)OnN(16-n):Eu ist, wobei M mindestens eine Art von Element, ausgewählt aus der Gruppe bestehend aus Sr, Ca, Li und Y, darstellt, die Parameter n and m jeweils 0,0 ≤ n ≤ 2,5 und 0,5 ≤ m ≤ 5 erfüllen und der Parameter n eine elektrische Ladung von M ist; und Si6-zAlzOzN8-z:Eu, wobei der Parameter z 0 < z < 4,2 erfüllt.
     
    6. Das Wellenlängenumwandlungselement gemäß einem der Ansprüche 1 bis 5, wobei das fluoreszierende Material ferner mindestens eine Art von Seltenerdmetallaluminat fluoreszierendes Material, ausgewählt aus der Gruppe bestehend aus Y3Al5O12:Ce, (Y,Gd)3Al5O12:Ce, Y3(Al,Ga)5O12:Ce, (Y,Gd)3(Al,Ga)5O12:Ce, Tb3Al5O12:Ce und Lu3Al5O12:Ce, Sr4Al14O25:Eu,Mn, CaAl2O4:Eu,Mn, BaMg2Al16O27:Eu,Mn und BaMgAl10O17:Eu,Mn, umfasst.
     
    7. Das Wellenlängenumwandlungselement gemäß einem der Ansprüche 1 bis 6, wobei das fluoreszierende Material ferner mindestens eine Art von Erdalkalimetallaluminat fluoreszierendes Material, ausgewählt aus der Gruppe bestehend aus SrAl2O4:Eu, Sr4Al14O25:Eu, BaMg2Al16O27:Eu, BaMgAl10O17:Mn und BaMgAl10O17:Eu, umfasst.
     
    8. Das Wellenlängenumwandlungselement gemäß einem der Ansprüche 1, 2, 4, 6 und 7, wobei das fluoreszierende Material auf der Basis von Nitrid CaAlSiN3:Eu ist und das Seltenerdmetallalumniat Y3Al5O12 ist.
     
    9. Ein Verfahren zur Herstellung eines Wellenlängenumwandlungselements, umfassend:

    Herstellen eines Formkörpers, erhalten durch Mischen eines fluoreszierenden Materials, enthaltend mindestens Eines, ausgewählt aus der Gruppe bestehend aus einem fluoreszierenden Material auf der Basis von Nitrid und einem fluoreszierenden Material auf der Basis von Oxynitrid, und eines Aluminats, enthaltend mindestens Eines, ausgewählt aus der Gruppe bestehend aus einem Seltenerdmetallaluminat und einem Erdalkalimetallaluminat; und

    Sintern des Formkörpers, um ein Wellenlängenumwandlungselement, enthaltend ein fluoreszierendes Material und das Aluminat, zu erhalten, wobei der Gehalt eines aktivierenden Elements, ausgewählt aus Ce, Eu und Mn, in dem Aluminat weniger als 50 Massen-ppm beträgt, und

    wobei der Gehalt des Aluminats in dem Wellenlängenumwandlungselement 50 Massen-% oder mehr beträgt.


     
    10. Das Verfahren zur Herstellung eines Wellenlängenumwandlungselements gemäß Anspruch 9, wobei das Kalzinieren gemäß einem Festkörper-Kompressionssinterverfahren durchgeführt wird.
     
    11. Das Verfahren zur Herstellung eines Wellenlängenumwandlungselements gemäß Anspruch 9 oder 10, wobei der durchschnittliche Teilchendurchmesser des Aluminats in einem Bereich von 1 µm oder mehr und 25 µm oder weniger liegt.
     
    12. Das Verfahren zur Herstellung eines Wellenlängenumwandlungselements gemäß einem der Ansprüche 9 bis 11, wobei der durchschnittliche Teilchendurchmesser des fluoreszierenden Materials in einem Bereich von 1 µm oder mehr und 25 µm oder weniger liegt.
     
    13. Das Verfahren zur Herstellung eines Wellenlängenumwandlungselements gemäß einem der Ansprüche 9 bis 12, wobei das fluoreszierende Material auf der Basis von Nitrid CaAlSiN3:Eu ist und das Seltenerdmetallaluminat Y3Al5O12 ist.
     


    Revendications

    1. Elément de conversion de longueur d'onde comprenant :

    un matériau fluorescent contenant au moins un type choisi dans le groupe constitué par un matériau fluorescent à base de nitrure et un matériau fluorescent à base d'oxynitrure ; et

    un aluminate contenant au moins un type choisi dans le groupe constitué par un aluminate de métal des terres rares et un aluminate de métal alcalino-terreux,

    dans lequel la teneur de l'aluminate en l'élément activateur choisi parmi Ce, Eu et Mn est inférieure à 50 ppm en masse, et

    la teneur en l'aluminate de l'élément de conversion de longueur d'onde est de 50 % en masse ou plus.


     
    2. Elément de conversion de longueur d'onde selon la revendication 1, dans lequel l'aluminate de métal des terres rares est au moins un type choisi dans le groupe constitué par Y3Al5O12, (Y,Gd)3Al5O12, Y3(Al,Ga)5O12, (Y,Gd)3(Al,Ga)5O12, Tb3Al5O12 et Lu3Al5O12.
     
    3. Elément de conversion de longueur d'onde selon la revendication 1, dans lequel l'aluminate de métal alcalino-terreux est au moins un type choisi dans le groupe constitué par (Ca,Sr,Ba)Al2O4, (Ca,Sr,Ba)4Al14O25, (Ca,Sr,Ba)Al12O19, (Ca,Sr,Ba)Mg2Al16O27, et (Ca,Sr,Ba)MgAl10O17.
     
    4. Elément de conversion de longueur d'onde selon l'une quelconque des revendications 1 à 3, dans lequel le matériau fluorescent à base de nitrure est au moins un type choisi dans le groupe constitué par (Ca,Sr,Ba)AlSiN3:Eu, (Ca,Sr,Ba)AlSiN3:Ce, (Ca,Sr,Ba)2Si5N8:Eu, SrLiAl3N4:Eu, et La3Si6N11:Ce, CaAlSiN3:Eu, CaAlSiN3:Ce, (Ca,Sr)AlSiN3:Eu, (Ca,Sr)AlSiN3:Ce, Ca2Si5N8:Eu, et (Ca,Sr)2Si5N8:Eu.
     
    5. Elément de conversion de longueur d'onde selon l'une quelconque des revendications 1 à 3, dans lequel le matériau fluorescent à base d'oxynitrure est au moins un type choisi dans le groupe constitué par BaSi2O2N2:Eu ; Ba3Si6O12N2:Eu ; Mm/2Si12-(m+n)Al(m+n)OnN(16-n):Eu où M représente au moins un type d'élément choisi dans le groupe constitué par Sr, Ca, Li et Y, les paramètres n et m satisfont à 0,0 ≤ n ≤ 2,5 et 0,5 ≤ m ≤ 5 respectivement, et le paramètre n est une charge électrique de M ; et Si6-zAlzOzN8-z:Eu où le paramètre z satisfait à 0 < z < 4,2.
     
    6. Elément de conversion de longueur d'onde selon l'une quelconque des revendications 1 à 5, dans lequel le matériau fluorescent comprend en outre au moins un type de matériau fluorescent aluminate de métal des terres rares choisi dans le groupe constitué par Y3Al5O12:Ce, (Y,Gd)3Al5O12:Ce, Y3(Al,Ga)5O12:Ce, (Y,Gd)3(Al,Ga)5O12:Ce, Tb3Al5O12:Ce, et Lu3Al5O12:Ce, Sr4Al14O25:Eu,Mn, CaAl2O4:Eu,Mn, BaMg2Al16O27:Eu,Mn, et BaMgAl10O17:Eu,Mn.
     
    7. Elément de conversion de longueur d'onde selon l'une quelconque des revendications 1 à 6, dans lequel le matériau fluorescent comprend en outre au moins un type de matériau fluorescent aluminate de métal alcalino-terreux choisi dans le groupe constitué par SrAl2O4:Eu, Sr4Al14O25 :Eu, BaMg2Al16O27:Eu, BaMgAl10O17:Mn, et BaMgAl10O17:Eu.
     
    8. Elément de conversion de longueur d'onde selon l'une quelconque des revendications 1, 2, 4, 6 et 7, dans lequel le matériau fluorescent à base de nitrure est CaAlSiN3:Eu, et l'aluminate de métal des terres rares est Y3Al5O12.
     
    9. Procédé pour produire un élément de conversion de longueur d'onde, comprenant :

    la préparation d'un corps moulé obtenu par mélange d'un matériau fluorescent contenant au moins un type choisi dans le groupe constitué par un matériau fluorescent à base de nitrure et un matériau fluorescent à base d'oxynitrure et d'un aluminate contenant au moins un type choisi dans le groupe constitué par un aluminate de métal des terres rares et un aluminate de métal alcalino-terreux ; et

    le frittage du corps moulé pour que soit obtenu un élément de conversion de longueur d'onde contenant le matériau fluorescent et l'aluminate,

    dans lequel la teneur de l'aluminate en un élément activateur choisi parmi Ce, Eu et Mn est inférieure à 50 ppm en masse, et

    la teneur en l'aluminate de l'élément de conversion de longueur d'onde est de 50 % en masse ou plus.


     
    10. Procédé pour produire un élément de conversion de longueur d'onde selon la revendication 9, dans lequel la calcination est effectuée conformément à un procédé de frittage par compression de solide.
     
    11. Procédé pour produire un élément de conversion de longueur d'onde selon la revendication 9 ou 10, dans lequel la granulométrie moyenne de l'aluminate est située dans la plage de 1 µm ou plus et de 25 µm ou moins.
     
    12. Procédé pour produire un élément de conversion de longueur d'onde selon l'une quelconque des revendications 9 à 11, dans lequel la granulométrie moyenne du matériau fluorescent est située dans la plage de 1 µm ou plus et de 25 µm ou moins.
     
    13. Procédé pour produire un élément de conversion de longueur d'onde selon l'une quelconque des revendications 9 à 12, dans lequel le matériau fluorescent à base de nitrure est CaAlSiN3:Eu et l'aluminate de métal des terres rares est Y3Al5O12.
     




    Drawing








    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description