JP6068473B2 - Wavelength converting particle, wavelength converting member, and light emitting device - Google Patents

Description

  The present invention relates to a wavelength conversion particle that absorbs light and emits light having a wavelength different from that of the light, a wavelength conversion member including the wavelength conversion particle, and a light emitting device including the wavelength conversion member.

  2. Description of the Related Art Conventionally, LED lamps including LED chips are used in many fields such as signal lamps, mobile phones, various types of lighting, in-vehicle displays, and various types of display devices. Also, research and development of a light emitting device that realizes light emission with a color different from that of the LED chip by combining the LED chip with a phosphor that emits light of a longer wavelength by exciting the light emitted from the LED chip Is being carried out in various places.

  As this type of light emitting device, for example, a white light emitting device (white LED) that realizes an emission spectrum of white light by combining an LED chip and a phosphor has been commercialized. In addition, the application of white LEDs to backlights of liquid crystal displays, small strobes, and the like has become popular.

  In addition, with the recent increase in output of white LEDs, research and development for developing white LEDs for lighting applications has become active. Such a white LED for illumination is expected to serve as a fluorescent light alternative light source with a small environmental load by taking advantage of long life and mercury-free.

  As the above-mentioned white LED, for example, there is a light emitting device configured by combining a wavelength conversion member in which wavelength conversion particles made of phosphor particles are dispersed in a translucent medium with an LED chip that emits blue light ( For example, see Patent Document 1). At this time, red phosphor particles or green phosphor particles are used as the phosphor particles, and silicone resin or glass is used as the translucent medium.

  Here, the wavelength conversion particles in the wavelength conversion member disclosed in Patent Document 1 are phosphor particles (red phosphor particles, green phosphor particles) covered with a coating layer. The material of the coating layer has an intermediate refractive index between the refractive index of the phosphor particles and the refractive index of the translucent medium. Thereby, the incident efficiency of the light emitted from the LED chip into the phosphor particles (excitation efficiency of the excitation light to the phosphor particles) and the extraction efficiency of the light emitted from the phosphor particles are improved. Yes.

However, in the wavelength conversion member disclosed in Patent Document 1, if the refractive index of the phosphor particles is n ₁₁ , the refractive index of the translucent medium is n ₁₃ , and the refractive index of the coating layer is n ₁₂ , these refractive indexes are as follows. Are in a relationship of n ₁₃ <n ₁₂ <n ₁₁ . That is, the refractive index changes stepwise along the normal direction of the surface of the phosphor particles. As a result, a part of the light emitted from the LED chip is Fresnel-reflected at the interface between the translucent medium and the coating layer and the interface between the coating layer and the phosphor particles, and the light into the phosphor particles is reflected. Incidence efficiency is reduced.

Further, in the wavelength conversion member described above, the refractive index n ₁₂ of the coating layer is smaller than the refractive index n ₁₁ of the phosphor particles. Therefore, when the incident angle is greater than the critical angle, the light emitted from the phosphor particles is totally reflected at the interface between the phosphor particles and the coating layer, and the extraction efficiency of the light emitted from the phosphor particles is reduced. End up.

  Patent Document 1 also discloses that the wavelength conversion particle coating layer is a multi-layer coating composed of a plurality of layers, and the refractive indexes of these layers are sequentially decreased toward the outer surface side. As a result, the refractive index change at each interface of the phosphor particles, the coating layer, and the translucent medium is alleviated to improve the efficiency of light incident on the phosphor particles and the extraction efficiency of light emitted from the phosphor particles. I am trying.

JP 2007-324475 A

  However, when the coating layer is a multilayer coating, a large number of interfaces are formed in the coating layer, and Fresnel reflection and total reflection can occur at each interface. Therefore, Fresnel reflection and total reflection are not sufficiently suppressed. For this reason, further improvement in the incident efficiency of the light to the phosphor particles and the extraction efficiency of the light emitted from the phosphor particles has been desired. In addition, when forming a multilayer coating, there is a problem that cracks or delamination easily occurs in a plurality of layers constituting the multilayer coating. There is also a problem that costs associated therewith are required.

  The present invention has been made in view of the problems of such conventional techniques. And the objective is to provide the wavelength conversion particle which can aim at the further improvement of the incident efficiency of the light to a fluorescent substance particle, and the further extraction efficiency of the light radiated | emitted from a fluorescent substance particle. is there. Furthermore, the objective of this invention is providing a wavelength conversion member provided with this wavelength conversion particle, and a light-emitting device provided with this wavelength conversion member.

  The wavelength conversion particles according to the first aspect of the present invention are provided on the surface of the phosphor particles having an average particle diameter of 1 μm to 50 μm and the phosphor particles, the average particle diameter is smaller than the phosphor particles, and the average A plurality of second particles having a particle size of 40 nm to 1000 nm. The wavelength conversion particles are provided in a gap between the phosphor particles and the second particles, and have a plurality of third particles having an average particle size smaller than that of the second particles and an average particle size of 1 nm to 100 nm. Is provided.

  In the wavelength conversion particle according to the second aspect of the present invention, the refractive index of the second particle and the refractive index of the third particle are substantially the same in the wavelength conversion particle according to the first aspect.

  The wavelength conversion particle according to the third aspect of the present invention is the wavelength conversion particle according to the first or second aspect, wherein the refractive index of the second particle and the refractive index of the third particle are the refractive index of the phosphor particles. It is as follows.

  The wavelength conversion particle according to the fourth aspect of the present invention is the wavelength conversion particle according to any one of the first to third aspects, wherein the second particle and the third particle are in the excitation wavelength region of the phosphor particle. The light and phosphor particles are made of a metal oxide having a light transmittance of 50% or more in the emission wavelength region.

  In the wavelength conversion particle according to the fifth aspect of the present invention, the wavelength conversion particle according to any one of the first to fourth aspects is interposed between the phosphor particle, the second particle, and the third particle. And a first metal oxide layer covering the phosphor particles. The refractive index of the first metal oxide layer is equal to or lower than the refractive index of the phosphor particles, equal to or higher than the refractive index of the second particles, and equal to or higher than the refractive index of the third particles.

  The wavelength conversion particle according to the sixth aspect of the present invention is a composite in which the wavelength conversion particle according to any one of the first to fifth aspects is composed of phosphor particles, second particles, and third particles. A second metal oxide layer covering the substrate. The refractive index of the second metal oxide layer is lower than both the refractive index of the second particles and the refractive index of the third particles.

  The wavelength conversion member which concerns on the 7th aspect of this invention is equipped with the translucent medium and the wavelength conversion particle which concerns on either of the 1st thru | or 6th aspect disperse | distributed in the translucent medium. The refractive index of the translucent medium is lower than any of the refractive index of the phosphor particles, the refractive index of the second particles, and the refractive index of the third particles.

  A light-emitting device according to an eighth aspect of the present invention includes a light-emitting element and a wavelength conversion member according to a seventh aspect that emits light by absorbing light emitted from the light-emitting element.

Fig.1 (a) is a schematic sectional drawing which shows the wavelength conversion particle and wavelength conversion member which concern on 1st embodiment of this invention. FIG.1 (b) is a partial schematic sectional drawing of the wavelength conversion particle | grains and wavelength conversion member which are shown by Fig.1 (a). FIG.1 (c) is a graph which shows the change of the refractive index in the wavelength conversion member shown by Fig.1 (a). Fig.2 (a) is a schematic sectional drawing which shows the wavelength conversion particle and wavelength conversion member which concern on 2nd embodiment of this invention. FIG. 2B is a partial schematic cross-sectional view of the wavelength conversion particle and the wavelength conversion member shown in FIG. Fig.3 (a) is a schematic sectional drawing which shows the wavelength conversion particle and wavelength conversion member which concern on 3rd embodiment of this invention. FIG.3 (b) is a partial schematic sectional drawing of the wavelength conversion particle | grains and wavelength conversion member which are shown by Fig.3 (a). FIG.3 (c) is a graph which shows the change of the refractive index in the wavelength conversion member shown by Fig.3 (a). FIG. 4 shows the ratio of the difference between the refractive index of the translucent medium and the refractive index of the metal oxide layer to the refractive index of the translucent medium, and the translucent medium and the metal oxide layer in the third embodiment. It is a graph which shows the result of having simulated the relationship with the relative reflection loss in the interface. FIG. 5 is a partially broken perspective view showing the light emitting device according to the embodiment of the present invention. FIG. 6 is a cross-sectional view showing a light emitting device according to an embodiment of the present invention. FIG. 7 is a scanning electron micrograph on the surface of the green wavelength conversion particles obtained in Example 1. FIG. 8 is a scanning electron micrograph of a cross section of the green wavelength conversion particle obtained in Example 1. FIG. 9 is a scanning electron micrograph showing the third particles in the wavelength conversion particles in which the third particles consist only of Nb ₂ O ₅ nanoparticles. FIG. 10 is a scanning electron micrograph showing the third particles in the wavelength conversion particles in which the third particles are composed only of SiO ₂ nanoparticles.

  Hereinafter, the wavelength conversion particle, the wavelength conversion member, and the light emitting device according to the embodiment of the present invention will be described in detail. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio.

[Wavelength conversion particle and wavelength conversion member]
FIG. 1 schematically shows the wavelength conversion particle 7 and the wavelength conversion member 70 according to the first embodiment of the present invention. As shown in FIGS. 1A and 1B, the wavelength conversion particle 7 is configured by combining phosphor particles 71, second particles 72, and third particles 73. In the wavelength conversion particle 7, a plurality of second particles 72 cover the phosphor particles 71. Further, a plurality of third particles 73 are filled in the gaps between the phosphor particles 71 and the second particles 72.

  The wavelength conversion member 70 according to the present embodiment includes the wavelength conversion particles 7 and the translucent medium 75. In the wavelength conversion member 70, a plurality of wavelength conversion particles 7 are dispersed in the translucent medium 75. FIG. 1A schematically shows a partial cross section of the wavelength conversion member 70. In FIG. 1A, only one wavelength conversion particle 7 is shown. Moreover, the arrow in FIG.1 (b) and FIG.2 (b) shows the example of the direction of the incident light which injects into the wavelength conversion particle 7. FIG.

  In the wavelength conversion particle 7 according to the present embodiment, the incident efficiency of the excitation light to the phosphor particle 71 and the extraction efficiency of the converted light emitted from the phosphor particle 71 are improved. The reason is considered as follows.

  The second particles 72 are fixed to the phosphor particles 71 via the third particles 73, and the gap between the phosphor particles 71 and the second particles 72 is filled with the third particles 73. A plurality of tapered fine protrusions 74 are formed on the surface of the wavelength conversion particle 7. As a result, a pseudo moth-eye structure is formed on the wavelength conversion particle 7. Thereby, when light is incident on the wavelength conversion particle 7 and when light emitted from the phosphor particle 71 is emitted out of the wavelength conversion particle 7, a discontinuous change in the refractive index is suppressed, and Fresnel reflection. Is suppressed.

For example, in the wavelength conversion member 70, the wavelength conversion particles 7 are dispersed in a transparent medium (translucent medium 75), and the transparent medium enters between the fine protrusions 74 of the wavelength conversion particles 7. For this reason, when the refractive index of the phosphor particles 71 is n ₁ and the refractive index n ₃ of the translucent medium 75, as shown in FIG. 1C, from the transparent medium in the wavelength conversion member 70. The refractive index extending into the wavelength converting particle 7 changes from n ₃ to n ₁ . That, within the wavelength converting member 70, along a direction perpendicular to the envelope surface of a plurality of microprojections 74 in the wavelength conversion particles 7 changes from n ₃ to n _1. This makes it difficult for the refractive index to discontinuously change as in the case of a normal moth-eye structure. As a result, it is considered that the incident efficiency of the excitation light to the phosphor particles 71 and the extraction efficiency of the converted light emitted from the phosphor particles 71 are improved.

  The configuration of the wavelength conversion particle 7 and the wavelength conversion member 70 according to the present embodiment will be described in more detail.

  The phosphor particles 71 absorb light in the excitation wavelength region of the phosphor particles 71 (hereinafter referred to as excitation light) and emit light having a wavelength longer than that of the excitation light (hereinafter referred to as converted light). The phosphor particles 71 may be particles formed from an appropriate phosphor.

Based on the light emitted by the phosphor, examples of the phosphor include CaAlSiN ₃ : Eu ²⁺ , (Ca, Sr) AlSiN ₃ : Eu ²⁺ , CaS: Eu ²⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ^Examples thereof include red phosphors such as ²⁺ . Also, green phosphors such as CaSc ₂ O ₄ : Ce ³⁺ , Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce ³⁺ , (Ca, Sr, Ba) Al ₂ O ₄ : Eu ²⁺ , SrGa ₂ S ₄ : Eu ^2+, etc. Can be mentioned. ^Examples include yellow phosphors such as Y ₃ Al ₅ O ₁₂ : Ce ³⁺ , (Ca, Sr, Ba, Zn) ₂ SiO ₄ : Eu ^2+, and yellow-green phosphors such as (Ba, Sr) ₂ SiO ₄ : Eu ^2+. It is done. Further, orange phosphors such as Sr ₃ SiO ₅ : Eu ²⁺ and Ca _0.7 Sr _0.3 AlSiN ₃ : Eu ²⁺ are also included.

Further, based on the phosphor compound system, examples of the phosphor include (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce, (Ca, Sr, Ba) ₂ SiO ₄ : Eu, Li Examples thereof include oxide phosphors such as ₂ SrSiO ₄ : Eu and (Ba, Sr) ₃ SiO ₅ : Eu. Further, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, SrAl ₂ O ₄ : Eu, Tb ₃ Al ₅ O ₁₂ : Ce, BAM: Eu, BAM: Mn, Eu, (Mg, Ca, Sr, Ba) ₁₀ ( _{PO 4) 6 Cl 2: Eu} , Sr 5 (PO 4) 3 Cl: oxide-based phosphor such as Eu can also be mentioned. Furthermore, ZnS: Cu, Al, CaGa ₂ S ₄ : Eu, SrGa ₂ S ₄ : Eu, BaGa ₂ S ₄ : Eu, Ca (Ga, Al, In) ₂ S ₄ : Eu, Sr (Ga, Al, In And sulfide phosphors such as ₂ S ₄ : Eu, Ba (Ga, Al, In) ₂ S ₄ : Eu. Examples thereof also include oxysulfide phosphors such as Y ₂ O ₂ S: Eu and La ₂ O ₂ S: Eu. CaSi ₂ O ₂ N ₂ : Eu, SrSi ₂ O ₂ N ₂ : Eu, BaSi ₂ O ₂ N ₂ : Eu, (Ca, Ba) Si ₂ O ₂ N ₂ : Eu, (Sr, Ba) Si ₂ O ₂ Nitride-based or oxynitride-based phosphors such as N ₂ : Eu and (Ca, Sr) Si ₂ O ₂ N ₂ : Eu are also included.

  The particle diameter of the phosphor particles 71 is not particularly limited. However, the larger the average particle diameter of the phosphor particles 71, the smaller the defect density in the phosphor particles 71, the less energy loss during light emission, and the light emission efficiency. Get higher. For this reason, from the viewpoint of improving luminous efficiency, the average particle diameter of the phosphor particles 71 is preferably in the range of 1 μm to 50 μm, more preferably in the range of 5 μm to 50 μm. In particular, the average particle diameter of the phosphor particles 71 is preferably in the range of 8 μm to 50 μm. In this specification, as the value of “average particle diameter”, unless otherwise specified, an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM) is used. The value calculated as the average value of the particle diameters of the particles observed inside is adopted.

  The second particles 72 have a smaller average particle size than the phosphor particles 71, and the third particles 73 have a smaller average particle size than the second particles 72. The particle diameter of the second particle 72 is appropriately set so that the fine projection 74 having a desired size is formed on the wavelength conversion particle 7. For example, the average particle diameter is preferably in the range of 40 nm to 1000 nm. . The average particle diameter of the second particles 72 is more preferably in the range of 50 nm to 500 nm, and particularly preferably in the range of 100 nm to 300 nm. When the average particle diameter of the second particles 72 is smaller than 40 nm, the smoothness of the coating formed by the second particles 72 is increased. Therefore, the effect of suppressing Fresnel reflection due to the pseudo moth-eye structure is hardly exhibited, and the incident efficiency of excitation light and the extraction efficiency of converted light are lowered. On the other hand, when the average particle diameter of the second particles 72 is larger than 1000 nm, the particle diameter of the second particles 72 is relatively larger than the particle diameter of the phosphor particles 71, so It becomes difficult to form a film of the second particles 72 uniformly. Further, a gap is likely to be formed in the third particle 73 filled between the second particle 72 and the phosphor particle 71, and the incident efficiency of excitation light and the extraction efficiency of converted light may be reduced.

  The particle size of the third particle 73 is appropriately set so that the gap between the phosphor particle 71 and the second particle 72 is sufficiently filled with the third particle 73. The particle size of is preferably nano-sized. That is, the average particle diameter of the third particles 73 is preferably in the range of 1 nm to 100 nm. The average particle size of the third particles 73 is more preferably in the range of 1 nm to 30 nm, and particularly preferably in the range of 3 nm to 10 nm. When the average particle size of the third particles 73 is 100 nm or less, Mie scattering is suppressed, and the incident efficiency of the excitation light to the phosphor particles 71 and the extraction efficiency of the converted light emitted from the phosphor particles 71 are improved. improves. Further, when the average particle diameter of the third particles 73 is 100 nm or less, the third particles 73 can be easily filled between the second particles 72 and the phosphor particles 71 without a gap. When the average particle diameter of the third particles 73 is less than 1 nm, it becomes difficult to fill the third particles 73 between the second particles 72 and the phosphor particles 71 without gaps, and voids are generated. It becomes easy to do. As a result, the incident efficiency of excitation light and the extraction efficiency of converted light may be reduced. The particle size of the third particles 73 is determined by processing the sample with a focused ion beam (FIB) so that the cross-section is a field emission scanning electron microscope (FE-SEM) or a field emission transmission electron microscope (FE-TEM). It is possible to measure by confirming with.

  The second particles 72 are preferably spherical. In this case, Fresnel reflection in the wavelength conversion particle 7 is further suppressed, and the incident efficiency of the excitation light to the phosphor particle 71 and the extraction efficiency of the converted light emitted from the phosphor particle 71 are improved. In the case where the second particles 72 are spherical, the second particles 72 need only have a curved surface, and may not be a strict sphere.

  The refractive index of the second particles 72 and the refractive index of the third particles 73 are preferably substantially the same. In particular, the absolute value of the difference between the refractive index of the second particle 72 and the refractive index of the third particle 73 is preferably in the range of 0 to 0.2, and if it is in the range of 0 to 0.1. Further preferred. In this case, the reflection of light between the second particle 72 and the third particle 73 is suppressed, the incident efficiency of the excitation light to the phosphor particle 71, and the converted light emitted from the phosphor particle 71. Extraction efficiency is improved. It is particularly preferable that the difference between the refractive index of the second particle 72 and the refractive index of the third particle 73 is 0, that is, the refractive index of the second particle 72 and the refractive index of the third particle 73 are the same.

The refractive index of the second particles 72 and the refractive index of the third particles 73 are preferably equal to or lower than the refractive index of the phosphor particles 71. The refractive index of the translucent medium 75 is preferably lower than any of the refractive index of the phosphor particles 71, the refractive index of the second particles 72, and the refractive index of the third particles 73. In this case, a change in refractive index is likely to occur in the wavelength conversion member 70 so that the refractive index continuously decreases from n ₃ to n ₁ from the translucent medium 75 to the wavelength conversion particles 7. As a result, the incident efficiency of the excitation light to the phosphor particles 71 and the extraction efficiency of the converted light emitted from the phosphor particles 71 in the wavelength conversion member 70 are further improved.

  In particular, the difference between the refractive index of the second particles 72 and the refractive index of the third particles 73 and the refractive index of the phosphor particles 71 is preferably in the range of 0 to 0.2. A range of 1 is more preferable. In particular, the refractive index of the second particles 72, the refractive index of the third particles 73, and the refractive index of the phosphor particles 71 are preferably the same. In this case, the reflection of light within the wavelength conversion particle 7 is particularly suppressed, and the incident efficiency of the excitation light to the phosphor particle 71 and the extraction efficiency of the converted light emitted from the phosphor particle 71 in the wavelength conversion member 70 are reduced. Is further improved.

  From the viewpoint of improving the incident efficiency of excitation light and the extraction efficiency of converted light, the second particles 72 and the third particles 73 are formed of a material that is transparent to the excitation light and converted light of the phosphor particles 71. It is preferred that That is, it is preferable that excitation light and converted light can pass through the second particles 72 and the third particles 73. Specifically, the second particles 72 and the third particles 73 are formed from a material having a transmittance of 50% or more of light in the excitation wavelength region of the phosphor particles 71 and light in the emission wavelength region of the phosphor particles 71. It is preferred that Furthermore, the second particles 72 and the third particles 73 are more preferably formed from a material having the transmittance of 80% or more. The light transmittance here refers to the second particle 72 and the third particle 73 at the film thickness formed on the phosphor particle 71 by the second particle 72 and the third particle 73. It is the transmittance of the constituent material (bulk material).

The material of the second particles 72 and the third particles 73 is not particularly limited, and examples thereof include appropriate oxides, nitrides, oxynitrides, and the like. In particular, each of the second particles 72 and the third particles 73 is preferably formed from a metal oxide that is transparent to the excitation light and converted light of the phosphor particles 71. This metal oxide is preferably selected from transparent materials having a relatively high refractive index. Specific examples of such a metal oxide include an oxide containing at least one metal selected from the group consisting of Si, Al, Y, Zr, Ti, Mg, Ca, Sr, Ba, and Nb. When the metal oxide contains Si, the metal oxide is preferably a composite metal oxide further containing a metal other than Si from the viewpoint of adjusting the refractive index. Specific examples of the composite metal oxide include Ti _x Si _(1-X) O ₂ , Zr _x Si _(1-x) O _{2, and the} like.

Further, at least one of the second particle 72 and the third particle 73 is a particle constituted by combining two or more kinds of nanoparticles such as Al ₂ O ₃ nanoparticles and SiO ₂ nanoparticles, for example. There may be. In particular, the material of the second particles is preferably at least one selected from the group consisting of Y ₂ O ₃ , ZrO ₂ , TiO ₂ , Nb ₂ O ₅ , Al ₂ O ₃ and MgO.

The material of the third particles 73 is preferably at least one selected from the group consisting of SiO ₂ , Y ₂ O ₃ , ZrO ₂ , TiO ₂ , Nb ₂ O ₅ , Al ₂ O ₃ and MgO. For example, the third particle may be a particle made only of an oxide having the above composition. In addition, the third particle is composed of a composite material of Nb ₂ O ₅ and SiO ₂ ; a composite material of ZrO ₂ and SiO ₂ ; a composite material of TiO ₂ and SiO ₂ ; a composite material of Y ₂ O ₃ and SiO _2. The particles may contain two or more oxides having the above composition.

  The material of the second particles 72 and the material of the third particles 73 may be the same or different from each other. If the material of the second particle 72 and the material of the third particle 73 are the same, the refractive index of the second particle 72 and the refractive index of the third particle 73 are also the same, that is, the difference in refractive index between them. Is preferable in that 0 becomes zero.

Moreover, it is preferable that both the protrusion dimension H of the fine protrusion 74 in the wavelength conversion particle 7 and the interval D between the adjacent fine protrusions 74 are λ / n ₃ or less. Note that λ is the wavelength of the excitation light incident on the wavelength conversion particle 7, and n ₃ is the refractive index of the translucent medium 75 in the wavelength conversion member 70. In this case, Fresnel reflection and total reflection of the excitation light incident on the wavelength conversion particle 7 can be sufficiently suppressed. For example, when the excitation light is blue light having a wavelength of 480 nm and the material of the translucent medium 75 is a silicone resin having a refractive index of 1.4, the protrusion size and interval of the fine protrusions 74 are 480 / 1.4≈ It is preferable that it is 343 nm or less. In this case, it is preferable that the second particle 72 has a particle size of 343 nm or less. That is, the particle diameter of the second particles 72 is preferably λ / n ₃ or less. Further, when λ = 350 nm and n ₃ = 1.4, it is preferable that the maximum protrusion dimension and the maximum interval (maximum pitch) of the fine protrusions 74 are 250 nm. In the present specification, the protrusion dimension H of the fine protrusion 74 means the distance from the bottom of the fine protrusion 74, that is, the surface of the phosphor particle 71 to the tip of the protrusion, as shown in FIG. . Further, the interval D between the adjacent fine protrusions 74 refers to the distance between the apexes of the adjacent fine protrusions 74. Here, the protrusion dimension and interval of the fine protrusions 74 can be measured by SEM or TEM.

  Moreover, it is preferable that arithmetic mean roughness Ra prescribed | regulated by JIS B0601-2001 (ISO 4287-1997) of the surface of the wavelength conversion particle | grains 7 provided with the fine protrusion 74 is 125 nm or less. Moreover, it is preferable that the average length RSm of the contour curve element on the surface of the wavelength conversion particle 7 is 125 nm or less.

  When the wavelength conversion particle 7 according to the present embodiment is produced, there is no particular limitation as a method for combining the phosphor particle 71, the second particle 72, and the third particle 73. However, as a method for compounding, for example, a general wet coating method (sol-gel method), a spray coating method (spray dry method), or the like is applicable. For the third particles 73 used in this case, when the average particle size of the third particles 73 is 10 nm or less, in addition to the nanoparticle dispersion in which the third particles 73 are dispersed in a solvent, alkoxide hydrolysis is performed. So-called sol-gel materials such as decomposition condensates may be used. The sol-gel material is microscopically composed of an aggregate of third particles 73 having a size of several nm to 10 nm or less.

  An example of the manufacturing method of the wavelength conversion particle 7 is demonstrated. First, phosphor particles 71, second particles 72, and third particles 73 (or a dispersion of third particles 73) are prepared, and these are added to a dispersion medium such as water, whereby the mixed solution is prepared. Prepare. While stirring this mixed solution, it is spray dried using a spray dryer or the like. The solid material thus obtained is heated as necessary. Thereby, the wavelength conversion particle 7 can be obtained.

  Further, by adjusting the pH by adding acid or alkali to the mixed solution containing the phosphor particles 71, the second particles 72, and the third particles 73 as described above, the second particles 72 and the third particles 73 are added. The surface potential of the particles 73 may be close to the isoelectric point. Thereby, the phosphor particles 71, the second particles 72, and the third particles 73 can be combined to obtain the wavelength conversion particles 7.

  When obtaining the mixed liquid, it is preferable to use an organic solvent as a dispersion medium in the case where the phosphor particles 71 are phosphor particles that are relatively weak in water, such as oxides, sulfides, and oxysulfides. .

  In the mixed liquid, the second particles 72 in a powder state may be blended as they are, or a dispersion obtained by dispersing the second particles 72 in a solvent may be blended. Moreover, the powder-form 3rd particle | grains 73 may be mix | blended as it is to a liquid mixture, and the dispersion obtained by disperse | distributing the 3rd particle | grain 73 in a solvent may be mix | blended.

  The ratio of the second particles 72 and the third particles 73 to the phosphor particles 71 in the mixed liquid can be arbitrarily set according to the types of these particles. For example, the ratio of the second particles 72 to the phosphor particles 71 is preferably in the range of 0.25 to 100% by volume, and the ratio of the third particles 73 to the phosphor particles 71 is 0.25 to 100. It is preferably in the range of volume%. When the ratio is 0.25% by volume or more, the amount of the fine protrusions 74 on the surface of the wavelength conversion particle 7 is sufficiently increased, and the incident efficiency into the phosphor particle 71 and the radiation from the phosphor particle 71 are emitted. The light extraction efficiency is further improved. Further, when these ratios are 100% by volume or less, the second particles 72 and the third particles 73 that are not complexed with the phosphor particles 71 are hardly generated. Therefore, the second particle 72 and the third particle 73 that are not complexed with the phosphor particles 71 are prevented from inhibiting the incident efficiency and the like into the phosphor particles 71. Moreover, the effort for removing the second particles 72 and the third particles 73 that are not combined with the phosphor particles 71 is reduced.

  The ratio of the total amount of the phosphor particles 71, the second particles 72, and the third particles 73 in the mixed solution is in the range of 0.5 to 30% by volume, although it depends on the type of these particles. Is preferred. When this proportion is 30% by volume or less, aggregation of particles hardly occurs. Further, nozzle clogging during spray drying is suppressed. Moreover, the productivity of the wavelength conversion particle 7 will become it high that this ratio is 0.5 volume% or more.

  Moreover, the drying temperature at the time of spray drying should just be more than the temperature which the solvent to use volatilizes, for example, in the case of a water solvent, it is 100 degreeC or more, More preferably, it is 110 degreeC or more.

  The refractive index of the translucent medium 75 in the translucent member is preferably lower than any of the refractive index of the phosphor particles 71, the refractive index of the second particles 72, and the refractive index of the third particles 73. . As will be described later, when the wavelength conversion particle 7 includes the second metal oxide layer 77, the refractive index of the translucent medium 75 and the refractive index of the second metal oxide layer 77 are substantially the same. It is preferable that

  Examples of the material of the translucent medium 75 include a silicon compound having a siloxane bond and glass. These materials are excellent in heat resistance and light resistance (particularly durability against light having a short wavelength such as blue to ultraviolet light). Therefore, even if the excitation light incident on the wavelength conversion particle 7 is light in a wavelength range from blue light to ultraviolet light, the translucent medium 75 is suppressed from being deteriorated. Examples of silicon compounds include composites formed by crosslinking a silicone resin, a hydrolyzed condensate of organosiloxane, a condensate of organosiloxane, etc. by a known polymerization method (addition polymerization such as hydrosilylation, radical polymerization, etc.). Resin. Further, as the translucent medium 75, for example, an acrylic resin or an organic / inorganic hybrid material formed by mixing and bonding an organic component and an inorganic component at a nano level or a molecular level may be employed. .

  The content of the phosphor particles 71 in the wavelength conversion member 70 takes into consideration the types of the phosphor particles 71 and the translucent medium 75, the dimensions of the wavelength conversion member 70, the wavelength conversion capability required for the wavelength conversion member 70, and the like. To be determined as appropriate. The content of the phosphor particles 71 in the wavelength conversion member 70 is preferably in the range of 5 to 30% by mass, for example.

  When the wavelength conversion member 70 is irradiated with the excitation light of the phosphor particles 71, a part of the excitation light is absorbed by the phosphor particles 71 and emits fluorescence having a wavelength longer than that of the excitation light. Thereby, when the light passes through the wavelength conversion member 70, the wavelength of a part of the light is converted by the phosphor particles 71. Thereby, the light of the color according to the combination with the light irradiated to the wavelength conversion member 70 and the kind of the fluorescent substance particle 71 in the wavelength conversion member 70 is emitted from the wavelength conversion member 70.

  As described above, the wavelength conversion particles according to the embodiment of the present invention are provided on the surface of the phosphor particles having an average particle diameter of 1 μm to 50 μm and the phosphor particles, and the average particle diameter is smaller than the phosphor particles, And a plurality of second particles having an average particle diameter of 40 nm to 1000 nm. The wavelength conversion particles are provided in a gap between the phosphor particles and the second particles, and have a plurality of third particles having an average particle size smaller than that of the second particles and an average particle size of 1 nm to 100 nm. Is provided. Thereby, when light is incident on the wavelength conversion particles and when light is emitted from the wavelength conversion particles, discontinuous change in the refractive index is suppressed, and Fresnel reflection is suppressed. As a result, it is possible to further improve the incident efficiency of light to the phosphor particles and the extraction efficiency of light emitted from the phosphor particles.

  Next, wavelength conversion particles according to the second embodiment of the present invention will be described. In the present embodiment, as shown in FIGS. 2A and 2B, the wavelength conversion particle 7 is a metal interposed between the phosphor particle 71, the second particle 72, and the third particle 73. An oxide layer (first metal oxide layer 76) is provided. In addition, since it is the same as that of 1st embodiment about structures other than the 1st metal oxide layer 76 in this embodiment, while omitting the description, about 1st Embodiment, about the element which is common in 1st Embodiment The same reference numerals as in the case of.

  As in the present embodiment, the wavelength conversion particle 7 has a metal oxide layer (first metal oxide layer 76) interposed between the phosphor particles 71, the second particles 72, and the third particles 73. You may prepare. That is, after the phosphor particles 71 are covered with the first metal oxide layer 76, the wavelength conversion particles 7 may be configured by being combined with the second particles 72 and the third particles 73. . Thus, when the wavelength conversion particle 7 includes the first metal oxide layer 76, moisture is shielded by the first metal oxide layer 76, and moisture hardly reaches the phosphor particles 71 from the outside. For this reason, deterioration of the phosphor particles 71 due to moisture is suppressed. Thereby, the durability of the wavelength conversion particle 7 is improved. Moreover, the freedom degree of selection of the material of the fluorescent substance particle 71 becomes high.

  From the viewpoint of improving the incident efficiency of excitation light and the extraction efficiency of converted light, the first metal oxide layer 76 is formed of a metal oxide that is transparent to the excitation light and converted light of the phosphor particles 71. Is preferred. That is, it is preferable that excitation light and converted light can pass through the first metal oxide layer 76. Specifically, the first metal oxide layer 76 is made of a material having a transmittance of 50% or more of light in the excitation wavelength region of the phosphor particles 71 and light in the emission wavelength region of the phosphor particles 71. Is preferred.

  Further, the refractive index of the first metal oxide layer 76 is equal to or lower than the refractive index of the phosphor particles 71, equal to or higher than the refractive index of the second particles 72, and equal to or higher than the refractive index of the third particles 73. Preferably there is. In this case, Fresnel reflection of light by the first metal oxide layer 76 is suppressed, and the efficiency of light incident on the phosphor particles 71 and the extraction efficiency of light emitted from the phosphor particles 71 are maintained high. In particular, the refractive index of the first metal oxide layer 76, the refractive index of the phosphor particles 71, the refractive index of the second particles 72, and the refractive index of the third particles 73 are preferably the same.

  The metal oxide that is the material of the first metal oxide layer 76 is not particularly limited, but is selected from the group consisting of Si, Al, Y, Zr, Ti, Mg, Ca, Sr, Ba, Nb, and Ge. Examples thereof include metal oxides containing at least one metal.

  The thickness of the first metal oxide layer 76 is not particularly limited, but is preferably 50 nm to 500 nm, for example. When the thickness of the first metal oxide layer 76 is 500 nm or less, the first metal oxide layer 76 is hardly cracked, and the first metal oxide layer 76 is difficult to prevent light transmission. Become. Further, when the thickness is 50 nm or more, the first metal oxide layer 76 exhibits sufficiently high moisture-proof performance. More preferably, the thickness of the first metal oxide layer 76 is 100 nm to 250 nm.

  In order for moisture to be sufficiently shielded by the first metal oxide layer 76, the first metal oxide layer 76 is preferably a highly dense film. In this case, for example, the first metal oxide layer 76 is composed of a film composed of fine nanoparticles having a particle diameter of 10 nm or less, a film formed by a sol-gel method, a composite film composed of these two kinds of films, and the like. It is preferable.

  A method for forming the first metal oxide layer 76 is not particularly limited, and examples thereof include a sol-gel method and a plasma deposition method. In order to densify the first metal oxide layer 76, it is also preferable to heat-treat the first metal oxide layer 76.

  Next, wavelength conversion particles according to the third embodiment of the present invention will be described. In the present embodiment, as shown in FIGS. 3A and 3B, the wavelength conversion particle 7 is a composite composed of phosphor particles 71, second particles 72, and third particles 73. An overlying metal oxide layer is provided. In addition, since it is the same as that of 1st embodiment about structures other than the 2nd metal oxide layer 77 in this embodiment, while omitting the description, it is about 1st Embodiment about the element which is common in 1st embodiment. The same reference numerals as in the case of.

  As in the present embodiment, the wavelength conversion particle 7 may include a second metal oxide layer 77 that covers a composite composed of phosphor particles 71, second particles 72, and third particles 73. . In this case, the wavelength conversion particle 7 may further include a first metal oxide layer 76 as in the case of the second embodiment. That is, after the phosphor particles 71 are covered with the first metal oxide layer 76, the phosphor particles 71 are combined with the second particles 72 and the third particles 73 to form a complex. The wavelength conversion particle 7 may be configured by being covered with the second metal oxide layer 77. Thus, when the wavelength conversion particle 7 includes the second metal oxide layer 77, moisture is shielded by the second metal oxide layer 77, and moisture hardly reaches the phosphor particles 71 from the outside. For this reason, deterioration of the phosphor particles 71 due to moisture is suppressed. Thereby, the durability of the wavelength conversion particle 7 is improved. Moreover, the freedom degree of selection of the material of the fluorescent substance particle 71 becomes high. Further, the second metal oxide layer 77 prevents the second particles 72 and the third particles 73 from falling off.

  The refractive index of the second metal oxide layer 77 is preferably lower than both the refractive index of the second particles 72 and the refractive index of the third particles 73. The refractive index of the second metal oxide layer 77 and the refractive index of the translucent medium 75 are preferably substantially the same. In this case, reflection of light between the translucent medium 75 and the second metal oxide layer 77 is suppressed, and the incident efficiency of excitation light to the phosphor particles 71 and the phosphor particles 71 are emitted. The extraction efficiency of the converted light is further improved.

This point will be described in more detail. First, the refractive index of the phosphor particles 71 is n ₁ , the refractive index of the translucent medium 75 is n ₃ , and the refractive index of the metal oxide constituting the second metal oxide layer 77 is n ₄ . In this case, the refractive index (effective refractive index) from the translucent medium 75 to the wavelength converting particle 7 in the wavelength converting member 70 is plural in the wavelength converting particle 7 as shown in FIG. along the direction orthogonal to the envelope surface of the microprojections 74, changes from n ₃ to n ₁ through n _4. Therefore, if the refractive index n _{4 of} the second metal oxide layer 77 is substantially the same as the refractive index n ₃ of the translucent medium 75, it is between the second metal oxide layer 77 and the translucent medium 75. Is suppressed, and the effective refractive index in the wavelength conversion member 70 continuously changes from n ₁ to n ₃ . Therefore, the refractive index n ₄ of the metal oxide layer is preferably substantially the same as the refractive index n ₃ of the transparent medium 75, and more preferably the same. In FIG. 3C , n _4max and n _4min indicate the upper limit value and lower limit value of n ₄ when n ₄ and n ₃ are substantially the same, respectively.

The conditions under which the refractive index n _{4 of} the second metal oxide layer 77 is considered to be substantially the same as the refractive index n ₃ of the translucent medium 75 will be described. First, the refractive index difference between the refractive index _{n 4} of the refractive index _{n 3} and a metal oxide layer of the transparent medium 75 a ratio of relative refractive index _{n 3} of the transparent medium _{75 (| | n 3 -n 4} ) Is represented as “{| n ₃ −n ₄ | / n ₃ } × 100”. In FIG. 4, “{| n ₃ −n ₄ | / n ₃ } × 100” and relative reflection at the interface (refractive index interface) between the translucent medium 75 and the second metal oxide layer 77. The result of having simulated the relationship with loss (relative value of the reflection loss which considered only the regular reflection component) is shown. As shown in FIG. 4, when the ratio of the refractive index difference to the refractive index n ₃ is 22% or more, the relative reflection loss at the interface (refractive index interface) between the translucent medium 75 and the second metal oxide layer 77. Exceeds 1%. From the viewpoint of improving the incident efficiency of the excitation light to the phosphor particles 71 and the extraction efficiency of the converted light emitted from the phosphor particles 71, the value of the relative reflection loss of 1% is not negligible. Therefore, in the present embodiment, when the ratio of the refractive index difference to the refractive index n ₃ is 15% or less (when the relative reflection loss is 0.5% or less), the second metal oxide layer 77 is refracted. The rate n ₄ is considered to be substantially the same as the refractive index n ₃ of the translucent medium 75.

The metal oxide that is the material of the second metal oxide layer 77 is not particularly limited, but is selected from the group consisting of Si, Al, Y, Zr, Ti, Mg, Ca, Sr, Ba, Nb, and Ge. Examples thereof include metal oxides containing at least one metal. For example, when the translucent medium 75 is made of a silicone resin having a refractive index of 1.4, the second metal oxide layer 77 is preferably made of an SiO ₂ film having a refractive index of 1.4.

  Although the thickness in particular of the 2nd metal oxide layer 77 is not restrict | limited, For example, it is preferable that they are 100 nm-150 nm.

  In order for moisture to be sufficiently shielded by the second metal oxide layer 77, the second metal oxide layer 77 is preferably a highly dense film. In this case, for example, the second metal oxide layer 77 is composed of a film composed of fine nanoparticles having a particle size of 10 nm or less, a film formed by a sol-gel method, a composite film composed of these two kinds of films, and the like. It is preferable. Examples of specific film forms constituting the second metal oxide layer 77 include an aggregate film of colloidal silica of 10 nm or less, and a hydrolyzate of Si-based alkoxides such as tetraethoxysilane and tetramethoxysilane. A sol-gel film may be mentioned. Examples of the second metal oxide layer 77 include a composite film composed of a colloidal silica aggregate film and a sol-gel film. From the viewpoint of improving the denseness of the second metal oxide layer 77, it is desirable that the second metal oxide layer 77 includes a sol-gel film.

  A method for forming the second metal oxide layer 77 is not particularly limited, and examples thereof include a sol-gel method and a plasma deposition method. In order to densify the second metal oxide layer 77, it is also preferable to heat-treat the second metal oxide layer 77.

[Light emitting device]
An embodiment of the light emitting device 1 including the wavelength conversion member 70 will be described. The light emitting device 1 includes a light emitting element and a wavelength conversion member 70 that emits light by absorbing light emitted from the light emitting element. As the wavelength conversion member 70, the wavelength conversion member 70 according to the first to third embodiments is used.

  The light emitting device shown in FIGS. 5 and 6 includes an LED chip 10 that is a light emitting element, a mounting substrate 20, an optical member 60, a sealing portion 50, and a wavelength conversion member (color conversion member) 70.

  The LED chip 10 is mounted on the mounting substrate 20. The shape of the mounting substrate 20 is a rectangular plate shape in plan view. A pair of conductor patterns 23 for supplying power to the LED chip 10 are formed on the first surface in the thickness direction of the mounting substrate 20, and the LED chip 10 is further mounted on the first surface. The LED chip 10 and the conductor pattern 23 are electrically connected by a bonding wire 14.

  The optical member 60 is a dome-shaped member, and is fixed on the first surface of the mounting substrate 20. The LED chip 10 is accommodated between the optical member 60 and the mounting substrate 20. The optical member 60 has a function of controlling the orientation of light emitted from the LED chip 10.

  The sealing part 50 is formed from a translucent sealing material. The sealing unit 50 is filled in a space surrounded by the optical member 60 and the mounting substrate 20. The sealing portion 50 seals the LED chip 10 and a plurality (two in this embodiment) of bonding wires 14.

  The wavelength conversion member 70 is formed in a dome shape so as to surround the optical member 60. When the LED chip 10 emits light, the phosphor particles 71 in the wavelength conversion member 70 are excited by the light emitted from the LED chip 10 (excitation light), and fluorescent light having a longer wavelength than the excitation light (the emission color of the LED chip 10). (Converted light consisting of light of a different color).

  A gap 80 in which a gas such as air exists is interposed between the optical member 60 and the wavelength conversion member 70. On the first surface of the mounting substrate 20, an annular weir 27 that surrounds the outer periphery of the optical member 60 is formed. The dam portion 27 is formed so as to protrude from the first surface. Therefore, when the optical member 60 is fixed to the mounting substrate 20, even if the sealing material overflows from the space surrounded by the optical member 60 and the mounting substrate 20, the sealing material is blocked by the dam portion 27. I can be dammed up.

  As the LED chip 10, for example, an LED chip having a main light emission peak in the range of 350 to 470 nm is used. Examples of such an LED chip 10 include a GaN-based blue LED chip that emits blue light and a near-ultraviolet LED chip that emits near-ultraviolet light.

  A GaN-based blue LED chip includes, for example, an n-type SiC substrate having a lattice constant or crystal structure closer to that of GaN than a sapphire substrate and having conductivity as a crystal growth substrate. On the SiC substrate, for example, a light-emitting portion having a double hetero structure is formed. The light emitting portion is formed by an epitaxial growth method (for example, MOVPE method) using, for example, a GaN compound semiconductor material as a raw material. The LED chip 10 includes a cathode electrode on the surface facing the first surface of the mounting substrate 20 and an anode electrode on the opposite surface. The cathode electrode and the anode electrode are composed of a laminated film of a Ni film and an Au film, for example. The material for the cathode electrode and the anode electrode is not particularly limited, and may be any material as long as good ohmic characteristics can be obtained. For example, Al may be used.

  The structure of the LED chip 10 is not limited to the above structure. For example, after a light emitting part or the like is formed by epitaxial growth on a crystal growth substrate, a support substrate such as an Si substrate that supports the light emitting part is fixed to the light emitting part, and then the crystal growth substrate is removed. The LED chip 10 may be formed.

  The mounting substrate 20 includes a rectangular heat transfer plate 21 and a wiring substrate 22. The heat transfer plate 21 is formed from a heat conductive material. The LED chip 10 is mounted on the heat transfer plate 21. The wiring board 22 is, for example, a rectangular flexible printed wiring board. The wiring board 22 is fixed on the heat transfer plate 21 via, for example, a polyolefin-based fixing sheet 29. A rectangular window hole 24 that exposes the mounting position of the LED chip 10 on the heat transfer plate 21 is formed at the center of the wiring board 22. Inside this window hole 24, the LED chip 10 is mounted on the heat transfer plate 21 via a submount member 30 described later. Therefore, the heat generated in the LED chip 10 is conducted to the submount member 30 and the heat transfer plate 21 without passing through the wiring board 22.

  The wiring substrate 22 includes an insulating base material 221 made of a polyimide film and a pair of conductor patterns 23 for supplying power to the LED chip 10 formed on the insulating base material 221. Furthermore, the wiring board 22 includes a protective layer 26 that covers each conductor pattern 23 and covers a portion of the insulating base material 221 where the conductor pattern 23 is not formed. The protective layer 26 is made of, for example, a white resist (resin) having light reflectivity. In this case, even if light is radiated from the LED chip 10 toward the wiring substrate 22, the light is reflected by the protective layer 26, thereby suppressing light absorption in the wiring substrate 22. Thereby, the light extraction efficiency from the LED chip 10 to the outside is improved, and the light output of the light emitting device is improved. Each conductor pattern 23 is formed in an outer peripheral shape slightly smaller than half of the outer peripheral shape of the insulating base material 221. The insulating base material 221 may be formed of an FR4 substrate, an FR5 substrate, a paper phenol resin substrate, or the like.

  Each conductor pattern 23 includes two terminal portions 231 each having a rectangular shape in plan view. The terminal portion 231 is located in the vicinity of the window hole 24 of the wiring board 22, and the bonding wire 14 is connected to the terminal portion 231. Each conductor pattern 23 further includes one external connection electrode portion 232 having a circular shape in plan view. The external connection electrode portion 232 is located near the outer periphery of the wiring board 22. The conductor pattern 23 is composed of, for example, a laminated film of a Cu film, a Ni film, and an Au film.

  The protective layer 26 is patterned so that each conductor pattern 23 is partially exposed from the protective layer 26. In the vicinity of the window hole 24 of the wiring board 22, the terminal portion 231 in each conductor pattern 23 is exposed from the protective layer 26. Further, the external connection electrode portions 232 in each conductor pattern 23 are exposed from the protective layer 26 near the outer periphery of the wiring board 22.

  The LED chip 10 is mounted on the heat transfer plate 21 via the submount member 30 as described above. The submount member 30 relieves stress acting on the LED chip 10 due to a difference in linear expansion coefficient between the LED chip 10 and the heat transfer plate 21. The submount member 30 is formed in a rectangular plate shape having a size larger than the chip size of the LED chip 10.

  The submount member 30 has not only a function of relieving the stress but also a heat conduction function of conducting heat generated in the LED chip 10 in a range wider than the chip size of the LED chip 10 in the heat transfer plate 21. ing. In the light emitting device 1 according to this embodiment, the LED chip 10 is mounted on the heat transfer plate 21 via the submount member 30, so that the heat generated by the LED chip 10 passes through the submount member 30 and the heat transfer plate 21. Heat dissipation. Further, the stress acting on the LED chip 10 due to the difference in linear expansion coefficient between the LED chip 10 and the heat transfer plate 21 is relieved.

  The submount member 30 is made of, for example, AlN having a relatively high thermal conductivity and an insulating property.

  The cathode electrode of the LED chip 10 is overlaid on the submount member 30. The cathode electrode is connected to one of the two conductor patterns 23 via a bonding wire 14 made of an electrode pattern (not shown) connected to the cathode electrode and a fine metal wire (for example, a gold fine wire, an aluminum fine wire, etc.). Electrically connected. The LED chip 10 is electrically connected through a bonding wire 14 to a conductor pattern 23 that is not connected to the cathode electrode.

  For joining the LED chip 10 and the submount member 30, for example, solder such as SnPb, AuSn, SnAgCu, silver paste, or the like is used. It is particularly preferable to use lead-free solder such as AuSn or SnAgCu. When the submount member 30 is made of Cu and AuSn is used for bonding the LED chip 10 and the submount member 30, pretreatment is performed on the surfaces of the submount member 30 and the LED chip 10 to be bonded to each other. It is preferable. As pretreatment, it is preferable to form a metal layer made of Au or Ag in advance.

  For joining the submount member 30 and the heat transfer plate 21, for example, lead-free solder such as AuSn or SnAgCu is preferably used. When AuSn is used for joining the submount member 30 and the heat transfer plate 21, a pretreatment for forming a metal layer made of Au or Ag in advance on the surface of the heat transfer plate 21 to be joined with the submount member 30. Is preferably applied.

  The material of the submount member 30 is not limited to AlN, but is preferably a material having a linear expansion coefficient that is relatively close to 6H—SiC that is a material for a crystal growth substrate and a relatively high thermal conductivity. For example, composite SiC, Si, Cu, CuW, or the like may be employed as the material of the submount member 30. Since the submount member 30 has the above-described heat conduction function, the area of the surface of the heat transfer plate 21 facing the LED chip 10 is the area of the surface of the LED chip 10 facing the heat transfer plate 21. It is desirable that it be sufficiently large.

  In the light emitting device 1 according to the present embodiment, the thickness of the submount member 30 is larger than the thickness of the wiring board 22 as shown in FIG. That is, the upper surface of the submount member 30 protrudes above the upper surface of the protective layer 26 of the wiring board 22. For this reason, the light emitted from the LED chip 10 is suppressed from being absorbed by the wiring board 22 through the inside of the window hole 24 of the wiring board 22. Thereby, the light extraction efficiency from the LED chip 10 to the outside is further improved, and the light output of the light emitting device is further improved.

  A reflective film that reflects light emitted from the LED chip 10 may be formed around the contact surface between the submount member 30 and the LED chip 10. In this case, the light emitted from the LED chip 10 is prevented from being absorbed by the submount member 30. Thereby, the light extraction efficiency from the LED chip 10 to the outside is further improved, and the light output of the light emitting device is further improved. The reflective film is composed of, for example, a laminated film of a Ni film and an Ag film.

  A silicone resin is mentioned as a sealing material which is a material for forming the above-mentioned sealing part 50. For example, an acrylic resin, glass, or the like may be used instead of the silicone resin.

  The optical member 60 is formed from a light transmissive material (eg, silicone resin, glass, etc.). In particular, when the optical member 60 is formed of a silicone resin, a difference in refractive index and a difference in linear expansion coefficient between the optical member 60 and the sealing portion 50 can be reduced.

  The first light exit surface 602 (surface opposite to the LED chip 10) of the optical member 60 is such that the light incident from the first light incident surface 601 (surface on the LED chip 10 side) into the optical member 60 is first. A convex curved surface is formed so as not to be totally reflected at the boundary between the light emitting surface 602 and the gap 80. The optical member 60 is disposed so that the optical axis of the LED chip 10 coincides. Therefore, the light emitted from the LED chip 10 and incident on the first light incident surface 601 of the optical member 60 is not totally reflected at the boundary between the first light emitting surface 602 and the gap 80 and reaches the wavelength conversion member 70. Easier to reach. Therefore, the total luminous flux emitted from the light emitting device 1 increases. The optical member 60 is formed to have a uniform thickness along the normal direction regardless of the position.

  The wavelength conversion member 70 has a second light incident surface 701 (a surface on the LED chip 10 side) formed in a shape along the first light emission surface 602 of the optical member 60. Therefore, regardless of the position of the first light exit surface 602 of the optical member 60, the distance between the first light exit surface 602 of the optical member 60 and the wavelength conversion member 70 in the normal direction is a substantially constant value. . The wavelength conversion member 70 is formed so that the thickness along the normal direction is uniform regardless of the position. The wavelength conversion member 70 is fixed to the mounting substrate 20 with, for example, an adhesive (for example, silicone resin, epoxy resin).

  The light emitted from the LED chip 10 enters the wavelength conversion member 70 from the second light incident surface 701 and is converted through the second light emission surface (surface opposite to the LED chip 10) 702 of the wavelength conversion member 70. The light is emitted out of the member 70. When light passes through the wavelength conversion member 70, a part of this light is wavelength-converted by the phosphor particles in the wavelength conversion member 70. As a result, light of a color corresponding to the combination of the light emitted from the LED chip 10 and the type of phosphor particles in the wavelength conversion member 70 is emitted from the light emitting device 1.

  Moreover, in this light-emitting device 1, the above-mentioned wavelength conversion member 70 is used as a color conversion member which converts and radiates | emits a part of light radiated | emitted from LED chip 10 to the light of longer wavelength than the said light. Therefore, the incident efficiency of the excitation light to the phosphor particles 71 in the wavelength conversion member 70 is further improved, and the extraction efficiency of the converted light from the phosphor particles 71 is further improved. Output can be increased.

  Note that the structure of the light-emitting device is not limited to the above description. Further, the shape of the wavelength conversion member 70 is not limited to a dome shape, and may be a sheet shape, for example.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples.

[Example 1]
(1) Preparation of green wavelength conversion particles First, green phosphor particles (CaSc ₂ O ₄ : Ce ³⁺ , refractive index 1.9, center particle size d ₅₀ : 8 μm) were prepared as phosphor particles. Moreover, Y ₂ O ₃ spherical fine particles (center particle diameter d ₅₀ : 250 nm, refractive index 1.8) were prepared as the second particles. Further, Nb ₂ O ₅ nanoparticle aqueous dispersion and SiO ₂ nanoparticle aqueous dispersion were prepared as the aqueous dispersion of third particles. The Nb ₂ O ₅ nanoparticle aqueous dispersion has a center particle diameter d ₅₀ of about 5 nm, a refractive index of Nb ₂ O ₅ of 2.2, and a solid content ratio of 6% by mass, manufactured by Taki Chemical Co., Ltd. I used one. The SiO ₂ nanoparticle aqueous dispersion used was a product manufactured by Nissan Chemical Industries, Ltd. having a center particle diameter d ₅₀ of 10 nm, a refractive index of SiO ₂ of 1.4, and a solid content ratio of 10% by mass. . In this example and comparative example, the center particle diameter d ₅₀ of the phosphor particles, the second particles, and the third particles is measured by a laser diffraction / scattering method.

Next, 5 g of phosphor particles and 0.68 g of second particles are dispersed in 100 mL of pure water, and 3.5 g of Nb ₂ O ₅ nanoparticle aqueous dispersion as an aqueous dispersion of third particles and A mixed solution was prepared by adding 0.69 g of the SiO ₂ nanoparticle aqueous dispersion. While stirring this mixed solution with a magnetic stirrer, it was spray-dried using a spray dryer (GBS210-A manufactured by Yamato Scientific Co., Ltd.). The obtained sample was further heated at 700 ° C. for 1 hour using an electric furnace (manufactured by Advantech Toyo Co., Ltd., model number KM-600). Thereby, wavelength conversion particles were obtained. The arithmetic average roughness Ra of the surface of the wavelength conversion particle was 250 nm, and the average length RSm of the contour curve element was 250 nm.

(2) Preparation of red wavelength conversion particles First, red phosphor particles (CaAlSiN ₃ : Eu ²⁺ , refractive index 2.0, center particle diameter d ₅₀ : 10 μm) were prepared as phosphor particles. Moreover, ZrO ₂ spherical fine particles (center particle diameter d ₅₀ : 250 nm, refractive index 2.1) were prepared as the second particles. Further, Nb ₂ O ₅ nanoparticle aqueous dispersion and SiO ₂ nanoparticle aqueous dispersion were prepared as the aqueous dispersion of third particles. The Nb ₂ O ₅ nanoparticle aqueous dispersion has a center particle diameter d ₅₀ of about 5 nm, a refractive index of Nb ₂ O ₅ of 2.2, and a solid content ratio of 6% by mass, manufactured by Taki Chemical Co., Ltd. I used one. The SiO ₂ nanoparticle aqueous dispersion used was a product manufactured by Nissan Chemical Industries, Ltd. having a center particle diameter d ₅₀ of 10 nm, a refractive index of SiO ₂ of 1.4, and a solid content ratio of 10% by mass. .

Next, 5 g of the phosphor particles and 0.55 g of the second particles are dispersed in 100 mL of pure water, and 3.4 g of Nb ₂ O ₅ nanoparticle aqueous dispersion as an aqueous dispersion of the third particles and A mixed solution was prepared by adding 0.11 g of the SiO ₂ nanoparticle aqueous dispersion. While stirring this mixed solution with a magnetic stirrer, it was spray-dried using a spray dryer (GBS210-A manufactured by Yamato Scientific Co., Ltd.). The obtained sample was further heated at 700 ° C. for 1 hour using an electric furnace (manufactured by Advantech Toyo Co., Ltd., model number KM-600). Thereby, wavelength conversion particles were obtained. The arithmetic average roughness Ra of the surface of the wavelength conversion particle was 250 nm, and the average length RSm of the contour curve element was 250 nm.

(3) Production of Wavelength Conversion Member and Light-Emitting Device The wavelength conversion member is formed by dispersing the above-described green wavelength conversion particle and red wavelength conversion particle in a silicone resin having a refractive index of 1.4 and forming a dome shape. Got. The mass ratio of the green wavelength conversion particles in this wavelength conversion member is 0.085, and the mass ratio of the red wavelength conversion particles is 0.015.

  Using this wavelength conversion member, a blue LED chip having an emission peak wavelength of 460 nm was adopted as a light emitting element, and a light emitting device having a structure shown in FIGS. 5 and 6 was produced.

[Example 2]
(1) Preparation of green wavelength conversion particles First, green phosphor particles (CaSc ₂ O ₄ : Ce ³⁺ , refractive index 1.9, center particle size d ₅₀ : 8 μm) were prepared as phosphor particles. Moreover, Y ₂ O ₃ spherical fine particles (center particle diameter d ₅₀ : 250 nm, refractive index 1.8) were prepared as the second particles. Furthermore, a Y ₂ O ₃ nanoparticle ethanol dispersion (center particle diameter d ₅₀ : about 8 nm, Y ₂ O ₃ refractive index 1.8) was prepared as a dispersion of _third particles.

Next, 5 g of phosphor particles and 0.68 g of second particles are dispersed in 100 mL of ethanol, and 3.1 g of Y ₂ O ₃ nanoparticle ethanol dispersion liquid is added thereto as a dispersion of _third particles. Thus, a mixed solution was prepared. While stirring this mixed solution with a magnetic stirrer, it was spray-dried using a spray dryer (GBS210-A manufactured by Yamato Scientific Co., Ltd.). The obtained sample was further heated at 700 ° C. for 1 hour using an electric furnace (manufactured by Advantech Toyo Co., Ltd., model number KM-600). Thereby, wavelength conversion particles were obtained. The arithmetic average roughness Ra of the surface of the wavelength conversion particle was 250 nm, and the average length RSm of the contour curve element was 250 nm.

(2) Preparation of red wavelength conversion particles First, red phosphor particles (CaAlSiN ₃ : Eu, refractive index 2.0, center particle diameter d ₅₀ : 10 μm) were prepared as phosphor particles. Moreover, ZrO ₂ spherical fine particles (center particle diameter d ₅₀ : 250 nm, refractive index 2.1 were prepared as the _second particles. Further, as the aqueous dispersion of the third particles, a TiO ₂ nanoparticle ethanol dispersion ( A center particle size d ₅₀ : about 6 nm, a refractive index of TiO ₂ 2.3) and a SiO ₂ nanoparticle ethanol dispersion (center particle size d ₅₀ : 8 nm, a refractive index of SiO ₂ of 1.4) were prepared.

Next, 5 g of the phosphor particles and 0.55 g of the second particles are dispersed in 100 mL of ethyl alcohol, and 3.21 g of TiO ₂ nanoparticle ethanol dispersion liquid and SiO ₂ nano particles are dispersed therein as the third particle dispersion. A mixed solution was prepared by adding 0.12 g of particle ethanol dispersion. While stirring this mixed solution with a magnetic stirrer, it was spray-dried using a spray dryer (GBS210-A manufactured by Yamato Scientific Co., Ltd.). The obtained sample was further heated at 700 ° C. for 1 hour using an electric furnace (manufactured by Advantech Toyo Co., Ltd., model number KM-600). Thereby, wavelength conversion particles were obtained. The arithmetic average roughness Ra of the surface of the wavelength conversion particle was 250 nm, and the average length RSm of the contour curve element was 250 nm.

(3) Production of Wavelength Conversion Member and Light-Emitting Device The wavelength conversion member is formed by dispersing the above-described green wavelength conversion particle and red wavelength conversion particle in a silicone resin having a refractive index of 1.4 and forming a dome shape. Got. The mass ratio of the green wavelength conversion particles in this wavelength conversion member is 0.085, and the mass ratio of the red wavelength conversion particles is 0.015.

  Using this wavelength conversion member, a blue LED chip having an emission peak wavelength of 460 nm was adopted as a light emitting element, and a light emitting device having a structure shown in FIGS. 5 and 6 was produced.

[Example 3]
(1) Preparation of green wavelength conversion particles 1.0 g of green wavelength conversion particles obtained in Example 1, 100 g of isopropanol, 0.5 g of TEOS (tetraethylorthosilicate), 0.7 g of water, and acetic acid 0 as a catalyst A mixed solution was prepared by mixing 2 g. The mixture was stirred at 60 ° C. for 12 hours and then filtered to obtain a solid. The solid was washed, dried at 80 ° C., and further heated at 300 ° C. Thereby, green wavelength conversion particles provided with a metal oxide layer (second metal oxide layer) made of SiO ₂ having a refractive index of 1.43 were obtained.

(2) Preparation of red wavelength conversion particles 1.0 g of red wavelength conversion particles obtained in Example 1, 100 g of isopropanol, 0.4 g of TEOS (tetraethylorthosilicate), 0.6 g of water, and acetic acid 0 as a catalyst A mixed solution was prepared by mixing 2 g. The mixture was stirred at 60 ° C. for 12 hours and then filtered to obtain a solid. The solid was washed, dried at 80 ° C., and further heated at 300 ° C. Thereby, red wavelength conversion particles provided with a metal oxide layer (second metal oxide layer) made of SiO ₂ having a refractive index of 1.43 were obtained.

(3) Production of Wavelength Conversion Member and Light-Emitting Device The wavelength conversion member is formed by dispersing the above-described green wavelength conversion particle and red wavelength conversion particle in a silicone resin having a refractive index of 1.4 and forming a dome shape. Got. The ratio of green wavelength conversion particles in this wavelength conversion member is 0.085, and the ratio of red wavelength conversion particles is 0.015.

  Using this wavelength conversion member, a blue LED chip having an emission peak wavelength of 460 nm was adopted as a light emitting element, and a light emitting device having a structure shown in FIGS. 5 and 6 was produced.

[Example 4]
(1) Preparation of green wavelength conversion particles 10 g of green phosphor particles are mixed with 1000 g of isopropanol, 1.75 g of TEOS (tetraethylorthosilicate), 3.34 g of titanium isopropoxide, and 0.5 g of acetic acid as a catalyst. A mixed solution was prepared. As the green phosphor particles, CaSc ₂ O ₄ : Ce ³⁺ having a refractive index of 1.9 and a center particle diameter d ₅₀ of 8 μm was used. The mixture was stirred at 60 ° C. for 12 hours and then filtered to obtain a solid. The solid was washed, dried at 80 ° C., and further heated at 300 ° C. As a result, a metal oxide layer (first metal oxide layer) made of TiO ₂ —SiO ₂ having a refractive index of about 1.8 was formed on the surface of the green phosphor particles. The green phosphor particles were processed into a thin piece shape using a focused ion beam processing apparatus (FIB) and then observed in a cross section with TEM-EDX. As a result, the first phosphor containing Ti and Si elements having a thickness of 150 nm was obtained. It was confirmed that a metal oxide layer was formed.

Moreover, Y ₂ O ₃ spherical fine particles (center particle diameter d ₅₀ : 250 nm, refractive index 1.8) were prepared as the second particles. Further, Nb ₂ O ₅ nanoparticle aqueous dispersion and SiO ₂ nanoparticle aqueous dispersion were prepared as the aqueous dispersion of third particles. The Nb ₂ O ₅ nanoparticle aqueous dispersion has a center particle diameter d ₅₀ of about 5 nm, a refractive index of Nb ₂ O ₅ of 2.2, and a solid content ratio of 6% by mass, manufactured by Taki Chemical Co., Ltd. I used one. The SiO ₂ nanoparticle aqueous dispersion used was a product manufactured by Nissan Chemical Industries, Ltd. having a center particle diameter d ₅₀ of 10 nm, a refractive index of SiO ₂ of 1.4, and a solid content ratio of 10% by mass. .

5 g of green phosphor particles on which the first metal oxide layer was formed and 0.72 g of the second particles were dispersed in 100 mL of pure water. Further, 3.7 g of Nb ₂ O ₅ nanoparticle aqueous dispersion and 0.73 g of SiO ₂ nanoparticle aqueous dispersion were added as an aqueous dispersion of third particles to this dispersion to prepare a mixed solution. While stirring this mixed solution with a magnetic stirrer, it was spray-dried using a spray dryer (GBS210-A manufactured by Yamato Scientific Co., Ltd.). The obtained sample was further heated at 700 ° C. for 1 hour using an electric furnace (manufactured by Advantech Toyo Co., Ltd., model number KM-600). Thereby, wavelength conversion particles were obtained. The arithmetic average roughness Ra of the surface of the wavelength conversion particle was 250 nm, and the average length RSm of the contour curve element was 250 nm.

(2) Preparation of red wavelength conversion particles Red phosphor particles (CaAlSiN ₃ : Eu ²⁺ , refractive index 2.0, center particle size d ₅₀ : 10 μm) 10 g, isopropanol 1000 g, TEOS (tetraethylorthosilicate) 4 g, water 6 g And 2 g of acetic acid as a catalyst were mixed to prepare a mixed solution. The mixture was stirred at 60 ° C. for 12 hours and then filtered to obtain a solid. The solid was washed, dried at 80 ° C., and further heated at 300 ° C. Thus, a metal oxide layer (first metal oxide layer) made of SiO ₂ having a refractive index of 1.43 was formed on the surface of the red phosphor particles. The red phosphor particles were processed into a thin piece using a focused ion beam processing apparatus (FIB) and then observed in a cross section with TEM-EDX. As a result, the first metal oxide formed of a SiO ₂ film having a thickness of 150 nm was obtained. It was confirmed that a physical layer was formed.

Moreover, ZrO ₂ spherical fine particles (center particle diameter d ₅₀ : 250 nm, refractive index 2.1) were prepared as the second particles. Further, Nb ₂ O ₅ nanoparticle aqueous dispersion and SiO ₂ nanoparticle aqueous dispersion were prepared as the aqueous dispersion of third particles. The Nb ₂ O ₅ nanoparticle aqueous dispersion used was manufactured by Taki Chemical Co., Ltd., having a center particle size d ₅₀ of about 5 nm, a refractive index of 2.2, and a solid content ratio of 6% by mass. . The SiO ₂ nanoparticle aqueous dispersion used was a product manufactured by Nissan Chemical Industries, Ltd. having a center particle size d ₅₀ of 10 nm, a refractive index of 1.4, and a solid content ratio of 10% by mass.

5 g of the above-mentioned phosphor particles and 0.58 g of the second particles are dispersed in 100 mL of pure water, and 3.6 g of Nb ₂ O ₅ nanoparticle aqueous dispersion and SiO ₂ as an aqueous dispersion of the third particles are dispersed therein. _A mixed solution was prepared by adding 0.12 g of the ₂ nanoparticle aqueous dispersion. While stirring this mixed solution with a magnetic stirrer, it was spray-dried using a spray dryer (GBS210-A manufactured by Yamato Scientific Co., Ltd.). The obtained sample was further heated at 700 ° C. for 1 hour using an electric furnace (manufactured by Advantech Toyo Co., Ltd., model number KM-600). Thereby, wavelength conversion particles were obtained. The arithmetic average roughness Ra of the surface of the wavelength conversion particle was 250 nm, and the average length RSm of the contour curve element was 250 nm.

(3) Production of Wavelength Conversion Member and Light-Emitting Device The wavelength conversion member is formed by dispersing the above-described green wavelength conversion particle and red wavelength conversion particle in a silicone resin having a refractive index of 1.4 and forming a dome shape. Got. The mass ratio of the green wavelength conversion particles in this wavelength conversion member is 0.085, and the mass ratio of the red wavelength conversion particles is 0.015.

  Using this wavelength conversion member, a blue LED chip having an emission peak wavelength of 460 nm was adopted as a light emitting element, and a light emitting device having a structure shown in FIGS. 5 and 6 was produced.

[Comparative Example 1]
First, green phosphor particles (CaSc ₂ O ₄ : Ce ³⁺ , refractive index 1.9, center particle size d ₅₀ : 8 μm) and red phosphor particles (CaAlSiN ₃ : Eu ²⁺ , refractive index 2.0, center particles) Diameter d ₅₀ : 10 μm). Next, the wavelength conversion member was obtained by disperse | distributing green fluorescent substance particle and red fluorescent substance particle to the silicone resin of refractive index 1.4, and shape | molding in a dome shape. The mass ratio of the green phosphor particles in the wavelength conversion member is 0.085, and the mass ratio of the red phosphor particles is 0.015.

  Using this wavelength conversion member, a blue LED chip having an emission peak wavelength of 460 nm was adopted as a light emitting element, and a light emitting device having a structure shown in FIGS. 5 and 6 was produced.

[Evaluation test]
When the surface of the wavelength conversion particle obtained in Examples 1 to 4 was observed with a scanning electron microscope, it was observed that the second particle was spread on the surface of the phosphor particle. Moreover, after processing the wavelength conversion particle | grains obtained in Examples 1-4 into the shape of a flake using a focused ion beam processing apparatus (FIB), the cross section of this wavelength conversion particle | grain was observed with the scanning electron microscope. As a result, it was confirmed that the third particles were interposed between the phosphor particles and the second particles. An image obtained by photographing the surface of the green wavelength conversion particle in Example 1 with a scanning electron microscope is shown in FIG. 7, and a cross section of the green wavelength conversion particle in Example 1 is obtained with a scanning electron microscope. The obtained images are shown in FIG.

  From FIG. 7, it can be seen that the particle size of the second particle 72 is approximately 250 nm, the particle size is relatively uniform, and has a substantially spherical shape. Moreover, it turns out that the 2nd particle | grains 72 are formed on the surface of the fluorescent substance particle 71 in the state close | similar to a substantially single layer. From FIG. 7, most of the surface of the phosphor particles 71 is covered with the second particles 72, but there are also portions that are not covered with the second particles 72, and the surfaces of the phosphor particles 71 are not necessarily all. I understand that it does not have to be covered.

Furthermore, it can be seen from FIG. 8 that third particles 73 smaller than the second particles 72 are present between the second particles 72 and the surface of the phosphor particles 71. And in the wavelength conversion member 70, it turns out that the 3rd particle | grains 73 exist with the size of 100 nm or less smaller than the 2nd particle | grains 72. FIG. Furthermore, it can be seen that the third particles 73 exist in a form that fills the gap between the phosphor particles 71 and the second particles 72. The particle size of the third particle 73 shown in FIG. 8 is larger than the central particle size d ₅₀ (Nb ₂ O ₅ particle: 5 nm, SiO ₂ particle: 10 nm) at the time of preparation, _{This is because 2} O ₅ particles and SiO ₂ particles are aggregated to form third particles 73.

In FIG. 9, in the wavelength conversion particles third particles 73 consists only of _Nb 2 _{O 5} nanoparticles shows an SEM photograph of the third particles 73. FIG. 10 shows an SEM photograph of the third particle 73 in the wavelength conversion particle in which the third particle 73 is composed only of SiO ₂ nanoparticles. As shown in FIGS. 9 and 10, _Nb 2 _{O 5} nanoparticles and SiO ₂ nanoparticles is the third particle is found to be less of a particle, respectively 10 nm.

  Moreover, each light-emitting device obtained in Examples 1 to 4 and Comparative Example 1 was caused to emit light, and the initial value of the total luminous flux of light emitted from the light-emitting device was measured. Next, after performing a reliability acceleration test by continuously energizing the light-emitting device 1 in an atmosphere at a temperature of 85 ° C. and a relative humidity of 85% RH for 1000 hours, the total luminous flux of light emitted from the light-emitting device is again displayed. It was measured. The results are shown in Table 1. The total luminous flux values shown in Table 1 are relative values normalized with the initial value of Comparative Example 1 as 100.

  According to this result, the initial value of the total luminous flux is 11% higher in Example 1, 14% in Example 2, 10% in Example 3, and 12% higher in Example 4 than Comparative Example 1. Thereby, in Examples 1-4, it can confirm that the high output of an optical output is achieved.

  Further, the total luminous flux after the reliability acceleration test is higher in Examples 1 to 4 than in Comparative Example 1, and in particular, in Examples 3 and 4, the decrease in the total luminous flux is remarkably suppressed. Thereby, it can confirm that durability of the wavelength conversion particle improved by the 1st metal oxide layer and the 2nd metal oxide layer.

  The entire contents of Japanese Patent Application No. 2012-171353 (application date: August 1, 2012) and Japanese Patent Application No. 2012-242585 (application date: November 2, 2012) are incorporated herein by reference.

  Although the contents of the present invention have been described with reference to the embodiments, the present invention is not limited to these descriptions, and it is obvious to those skilled in the art that various modifications and improvements can be made. That is, the second particle 72, the first metal oxide layer 76, and the second metal oxide layer 77 described above do not have to completely cover the periphery of the phosphor particle 71, and are part as long as the above effect is exhibited. May be exposed. Further, the gap between the phosphor particles 71 and the second particles 72 need not be completely filled with the third particles 73, and a space may be partially formed as long as the above effect is exhibited. Absent.

  ADVANTAGE OF THE INVENTION According to this invention, the wavelength conversion particle | grains, wavelength conversion member, and light-emitting device which can aim at the further improvement of the incident efficiency of the light to fluorescent substance particle, and the extraction efficiency of the light radiated | emitted from fluorescent substance particle are obtained. Can do.

DESCRIPTION OF SYMBOLS 1 Light-emitting device 7 Wavelength conversion particle 70 Wavelength conversion member 71 Phosphor particle 72 Second particle 73 Third particle 75 Translucent medium 76 First metal oxide layer 77 Second metal oxide layer

Claims (7)

Phosphor particles having an average particle diameter of 1 μm to 50 μm;
A plurality of second particles provided on the surface of the phosphor particles, having an average particle size smaller than that of the phosphor particles, and having an average particle size of 40 nm to 1000 nm;
A plurality of third particles provided in a gap between the phosphor particles and the second particles, having an average particle size smaller than the second particles, and having an average particle size of 1 nm to 100 nm;
With
The wavelength conversion particle whose absolute value of the difference of the refractive index of said 2nd particle and the refractive index of said 3rd particle is 0-0.2 .   The wavelength conversion particle according to claim 1, wherein a refractive index of the second particle and a refractive index of the third particle are equal to or lower than a refractive index of the phosphor particle. The second particles and the third particles are formed of a metal oxide having a transmittance of 50% or more of light in an excitation wavelength region of the phosphor particles and light in an emission wavelength region of the phosphor particles. Item 3. The wavelength conversion particle according to Item 1 or 2 . A first metal oxide layer interposed between the phosphor particles and the second and third particles, and covering the phosphor particles;
The refractive index of the first metal oxide layer is equal to or lower than the refractive index of the phosphor particles, equal to or higher than the refractive index of the second particles, and equal to or higher than the refractive index of the third particles. Item 4. The wavelength converting particle according to any one of Items 1 to 3 . A second metal oxide layer covering a composite composed of the phosphor particles, the second particles, and the third particles;
The refractive index of the second metal oxide layer, the wavelength conversion according to the second refractive index and any one of the third refractive index any 1 to lower claim than 4 of particles having a particle particle. A translucent medium;
The wavelength conversion particles according to any one of claims 1 to 5 , which are dispersed in the translucent medium,
With
The wavelength conversion member whose refractive index of the translucent medium is lower than any of the refractive index of the phosphor particles, the refractive index of the second particles, and the refractive index of the third particles. A light emitting element;
The wavelength conversion member according to claim 6 , which emits light by absorbing light emitted from the light emitting element,
A light emitting device comprising: