JP5351669B2 - Wavelength converting member and light emitting device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wavelength conversion member further improving incident efficiency of exciting light into a fluorescent particle and extraction efficiency of converted light from the fluorescent particle; and to provide a light-emitting device using the member. <P>SOLUTION: The wavelength conversion member 70 includes an antireflection section 76 composed of: a moss eye-like structure 74 having minute concavo-convex structure on the surface-side of the fluorescent particle 71; and a translucent medium 73 intruding into tapering gaps between fine protrusions 75 of the moss eye-like structure 74. The individual fine protrusions 75 of the moss eye-like structure 74 are formed by combining fine particles 72 smaller in particle diameter than the fluorescent particle 71 and larger in refractive index than the translucent medium 73 with the fluorescent particles 71 on the surface-side of the fluorescent particle 71. When the refractive index n<SB>2</SB>of the fine particle 72 is made the same as the refractive index n<SB>1</SB>of the fluorescent particle 71, effective refractive index of the antireflection section 76 varies continuously between the refractive index n<SB>1</SB>of the fluorescent particle 71 and the refractive index n<SB>3</SB>of the translucent medium 73, in the normal direction of the surface of the fluorescent particle 71, as shown in Figure (d). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a wavelength conversion member in which phosphor particles are scattered in a translucent medium having a refractive index smaller than that of the phosphor particles, and in particular, light (excitation light) from an LED chip (light emitting diode chip) as the phosphor particles. ) And a wavelength conversion member using phosphor particles that emit visible light having a wavelength longer than that of the LED chip. The present invention also relates to a light emitting device using a wavelength conversion member.

  Conventionally, LED lamps using LED chips have been used in many fields such as signal lamps, mobile phones, various types of lighting, in-vehicle displays, and various types of display devices. Further, a light emitting device that emits light of a color different from the emission color of the LED chip by combining the LED chip and phosphor particles that are excited by the light emitted from the LED chip and emit light having a longer wavelength than the LED chip. Research and development are taking place at various locations. As this type of light-emitting device, for example, there is a commercialization of a white light-emitting device (generally called a white LED) that obtains white light (white light emission spectrum) by combining an LED chip and a phosphor. As a result, its application to liquid crystal display backlights, small strobes, etc. has become popular.

  In addition, with the recent increase in output of white LEDs, research and development to expand white LEDs into lighting applications has become active. By taking advantage of long life and mercury-free, it can replace fluorescent lamps with low environmental impact. Expected to be a light source.

  As the above-mentioned white LED, for example, an LED chip that emits blue light, and a wavelength conversion member (color conversion member) in which red phosphor particles and green phosphor particles are dispersed in a translucent medium (silicone resin, glass, etc.) ) In combination (for example, see Patent Document 1).

  Here, in the wavelength conversion member disclosed in Patent Document 1, phosphor particles (red phosphor particles, green phosphor particles) are covered with a light-transmitting film, and as a material of the light-transmitting film, Since one having a refractive index intermediate between the refractive index of the phosphor particles and the refractive index of the translucent medium is used, the efficiency with which the light emitted from the LED chip is incident on the phosphor particles (to the phosphor particles) (Incidence efficiency of excitation light) and extraction efficiency of converted light from the phosphor particles can be improved.

JP 2007-324475 A

However, in the wavelength conversion member disclosed in Patent Document 1, as shown in FIG. 8A, the refractive index of the phosphor particles 171 is n ₁₁ , the refractive index of the translucent medium 173 is n ₁₃ , and the translucent light is transmitted. Assuming that the refractive index of the conductive coating 172 is n ₁₂ , n ₁₃ <n ₁₂ <n ₁₁ and the refractive index changes stepwise in the normal direction of the surface of the phosphor particle 171 as shown in FIG. Since part of the excitation light from the LED chip is Fresnel-reflected at the interface between the translucent medium 173 and the translucent film 172 and at the interface between the translucent film 172 and the phosphor particles 171, It is desired to further improve the incident efficiency of the excitation light to the body particles 171. Further, in the above-described wavelength conversion member, the refractive index n ₁₂ of the light-transmitting coating 172 is smaller than the refractive index n ₁₁ of the phosphor particles 171, and the interface between the phosphor particles 171 and the light-transmitting coating 172. Therefore, since there is a total reflection angle at which the converted light from the phosphor particles 171 is totally reflected, further improvement in the extraction efficiency of the converted light from the phosphor particles 171 is desired.

  The present invention has been made in view of the above reasons, and its purpose is to further improve the incident efficiency of the excitation light to the phosphor particles and further improve the extraction efficiency of the converted light from the phosphor particles. It is an object to provide a wavelength conversion member capable of achieving the above and a light emitting device using the same.

The invention of claim 1 is a wavelength conversion member in which phosphor particles are scattered in a translucent medium having a refractive index smaller than that of the phosphor particles, and the moth-eye has a fine uneven structure on the surface side of the phosphor particles. Each of the fine projections of the moth-eye structure portion is more granular than the phosphor particles. It is formed by combining fine particles having a small diameter and a refractive index larger than that of the light-transmitting medium with the phosphor particles on the surface side of the phosphor particles, and the refractive index of the fine particles is the refractive index of the phosphor particles. It is characterized by being the same .

  According to this invention, on the surface side of the phosphor particles, an antireflection portion composed of a moth-eye structure portion having a fine concavo-convex structure and a translucent medium that has entered between the tapered fine protrusions of the moth-eye structure portion. Each of the fine projections of the moth-eye structure has a particle size smaller than that of the phosphor particles and a refractive index larger than that of the translucent medium, and is combined with the phosphor particles on the surface side of the phosphor particles. Therefore, by suppressing the Fresnel reflection, it is possible to further improve the incident efficiency of the excitation light to the phosphor particles and further improve the extraction efficiency of the converted light from the phosphor particles.

Further, according to the present invention, since the refractive index of the fine particles is the same as the refractive index of the phosphor particles, the effective refractive index of fluorescent particles of reflection preventing portion Te direction normal odor of the surface of the fluorescent particles since continuously varies between the refractive index and refractive index of the transparent medium, and to improve the extraction efficiency of the converted light from the improvement and phosphor particles of efficiency of incidence of the excitation light to the fluorescent particles I can plan.

The invention according to claim 2 is a wavelength conversion member in which phosphor particles are scattered in a light-transmitting medium having a refractive index smaller than that of the phosphor particles, and the moth-eye having a fine uneven structure on the surface side of the phosphor particles. Each of the fine projections of the moth-eye structure portion is more granular than the phosphor particles. diameter becomes formed by complexing the phosphor particles in the small and the surface side of the phosphor particles a refractive index of particulates larger than the transparent medium, the refractive index of refraction of the fine particles of the fluorescent particles It is characterized by being larger than the rate.

According to this invention, on the surface side of the phosphor particles, an antireflection portion composed of a moth-eye structure portion having a fine concavo-convex structure and a translucent medium that has entered between the tapered fine protrusions of the moth-eye structure portion. Each of the fine projections of the moth-eye structure has a particle size smaller than that of the phosphor particles and a refractive index larger than that of the translucent medium, and is combined with the phosphor particles on the surface side of the phosphor particles. Therefore, by suppressing the Fresnel reflection, it is possible to further improve the incident efficiency of the excitation light to the phosphor particles and further improve the extraction efficiency of the converted light from the phosphor particles. Further, according to this invention, since the refractive index of the fine particles is larger than the refractive index of the phosphor particles, as compared with the case where the refractive index of the fine particles is smaller than the refractive index of the fluorescent particles, fluorescent particles converted light from tends to enter the fine particles, it can be improved extraction efficiency of converted light from the fluorescent particles.

Formation of invention of claim 3, in the invention of claim 1 or billed to claim 2, wherein the fine particles of a transparent metal oxide with respect to converted light from the excitation light and the fluorescent particles to the phosphor particles It is characterized by being made.

  According to this invention, the fine particles are transparent to the excitation light to the phosphor particles and the converted light from the phosphor particles, and the excitation light and the converted light are prevented from being absorbed by the fine particles. Can do.

The invention of claim 4 is the invention of claim 1 or billed to claim 2, coated with a metal oxide layer across the surface of the phosphor particles having the phosphor particles substantially the same refractive index, the Fine particles are combined with the phosphor particles through the metal oxide layer. The substantially same means that the refractive index of the phosphor particles is n ₁ , and the refractive index of the metal oxide layer is n ₄ . The ratio {| n ₁ −n ₄ | / n ₁ } × 100 of the refractive index difference | n ₁ −n ₄ | to the refractive index n ₁ is 15% or less .

  According to the present invention, the entire surface of the phosphor particles is coated with the metal oxide layer having substantially the same refractive index as that of the phosphor particles, and a metal is disposed between the phosphor particles and the fine particles. Since the oxide layer is interposed, moisture from the outside can be prevented from reaching the phosphor particles, and moisture resistance can be improved (the characteristics of the phosphor particles are affected by humidity). The degree of freedom of selection of the material of the phosphor particles is increased, and the refractive index of the metal oxide layer is substantially the same as the refractive index of the phosphor particles. As a result, it is possible to suppress a decrease in the antireflection effect of the moth-eye structure and to suppress reflection of excitation light.

The invention of claim 5 is the invention of claim 1 or billed to claim 2, wherein the transparent medium has a light-transmitting base material in which the phosphor particles wherein the fine particles are complexed to the surface are scattered, A part of the anti-reflection portion is formed between the light-transmitting base material having a refractive index substantially the same as that of the light-transmitting base material, and being interposed between the composite particles of the phosphor particles and the fine particles. It is composed of a metal oxide layer, and the substantially same means that the refractive index difference | n ₃ −n when the refractive index of the translucent base material is n ₃ and the refractive index of the metal oxide layer is n _{4. The} ratio of ₄ | to the refractive index n ₃ {| n ₃ −n ₄ | / n ₃ } × 100 is 15% or less .

  According to this invention, the translucent medium has a refractive index substantially the same as that of the translucent base material in which the phosphor particles in which the fine particles are combined on the surface are scattered, and the translucent base material. The phosphor particles comprising a composite particle of the phosphor particles and the fine particles and a metal oxide layer that forms part of the antireflection portion interposed between the translucent base material. On the surface side, the gaps between the fine particles are coated with a metal oxide layer, so that moisture from the outside can be prevented from reaching the phosphor particles, and moisture resistance can be improved ( It is possible to suppress the deterioration of the characteristics of the phosphor particles due to the influence of humidity), so that the degree of freedom in selecting the material of the phosphor particles is increased, and the refractive index of the metal oxide layer is By being substantially the same as the refractive index of the translucent base material, The reflection of the excitation light can be suppressed can be suppressed to decrease the reflection preventing effect of the serial moth-eye-like structure.

According to a sixth aspect of the present invention, in the first to fourth aspects of the present invention, the translucent medium is a silicone resin or glass.

  According to this invention, it is possible to suppress deterioration of the translucent medium due to excitation light when general blue light or ultraviolet light is employed as excitation light for the phosphor particles.

The invention of claim 7 is the invention of claim 5 , wherein the translucent base material is a silicone resin or glass.

  According to this invention, it is possible to suppress deterioration of the translucent medium due to excitation light when general blue light or ultraviolet light is employed as excitation light for the phosphor particles.

The invention of claim 8 includes an LED chip and a color conversion member that converts and emits a part of light emitted from the LED chip into light having a longer wavelength than the light, and as the color conversion member. The wavelength conversion member according to any one of claims 1 to 7 is used.

According to this invention, the color conversion member that converts part of the light emitted from the LED chip into light having a longer wavelength than the light and emits the light is described in any one of claims 1 to 7 . Since the wavelength conversion member is used, it is possible to further improve the incident efficiency of the excitation light to the phosphor particles in the color conversion member and further improve the extraction efficiency of the converted light from the phosphor particles. High output can be achieved.

  In the invention of claim 1, there is an effect that it is possible to further improve the incident efficiency of the excitation light to the phosphor particles and further improve the extraction efficiency of the converted light from the phosphor particles.

According to the eighth aspect of the present invention, it is possible to further improve the incident efficiency of the excitation light to the phosphor particles in the color conversion member and further improve the extraction efficiency of the converted light from the phosphor particles. There is an effect that can be achieved.

Embodiment 1 is shown, (a) is a schematic cross-sectional view of a light emitting device using a wavelength conversion member, and (b) to (d) are explanatory views of the main part of the wavelength conversion member. It is a general | schematic disassembled perspective view of the light-emitting device same as the above. It is principal part explanatory drawing of the ideal wavelength conversion member in the same as the above. Embodiment 2 is shown, (a) is a schematic cross-sectional view of a light-emitting device using a wavelength conversion member, and (b) to (d) are explanatory views of main parts of the wavelength conversion member. It is principal part explanatory drawing of the wavelength conversion member in the same as the above. Embodiment 3 is shown, (a) is a schematic sectional drawing of the light-emitting device using the wavelength conversion member, (b)-(d) is principal part explanatory drawing of a wavelength conversion member. It is principal part explanatory drawing of the wavelength conversion member in the same as the above. It is principal part explanatory drawing of the wavelength conversion member which shows a prior art example.

(Embodiment 1)
In the present embodiment, the wavelength conversion member 70 will be described after the light emitting device 1 including the LED chip 10 and the wavelength conversion member 70 as illustrated in FIGS. 1A and 2 is described.

  The light emitting device 1 in the present embodiment has a rectangular plate shape in which the LED chip 10 has conductor patterns 23 and 23 for supplying power to the LED chip 10 on one surface side, and the LED chip 10 is mounted on the one surface side. An optical member that controls the light distribution of the light emitted from the mounting substrate 20 and the LED chip 10 and is fixed to the one surface side of the mounting substrate 20 in such a manner that the LED chip 10 is housed between the mounting substrate 20 and the mounting substrate 20. A plurality of dome-shaped optical members 60 made of a translucent material, and a plurality of LED chips 10 that are electrically connected to the LED chips 10 in a space surrounded by the optical members 60 and the mounting substrate 20 (books). In the embodiment, the sealing portion 50 made of a light-transmitting sealing material that seals the two bonding wires 14 and the excitation light that is excited by the light (excitation light) emitted from the LED chip 10. In addition, phosphor particles 71 (see FIG. 1B) that emit long-wavelength light (converted light composed of light of a color different from the emission color of the LED chip 10) are translucent medium 73 (FIG. 1B). Dome-shaped wavelength conversion member (color conversion member) 70 disposed on the one surface side of the mounting substrate 20 so as to surround the LED chip 10 and the like on the one surface side. The gas layer 80 (for example, air layer etc.) is formed between the optical member 60 and the wavelength conversion member 70. Here, the mounting substrate 20 has an annular weir 27 projecting outside the optical member 60 on the one surface and blocking the sealing resin overflowing from the space when the optical member 60 is fixed to the mounting substrate 20. It is installed.

  The LED chip 10 is a GaN-based blue LED chip that emits blue light, and uses an n-type SiC substrate having a lattice constant and a crystal structure close to GaN as compared to a sapphire substrate and having conductivity as a crystal growth substrate. In addition, a light emitting portion formed of a GaN-based compound semiconductor material and having a double-heterostructure, for example, on the main surface side of the SiC substrate is grown by an epitaxial growth method (for example, MOVPE method). Here, the LED chip 10 has an anode electrode (not shown) formed on one surface side (upper surface side in FIG. 1A) and a cathode electrode on the other surface side (lower surface side in FIG. 1A). Is formed. The cathode electrode and the anode electrode are composed of a laminated film of a Ni film and an Au film, but the material of the cathode electrode and the anode electrode is not particularly limited, and a material capable of obtaining good ohmic characteristics For example, Al or the like may be employed. Further, the structure of the LED chip 10 is not particularly limited. For example, a light emitting unit is formed by supporting a light emitting unit after epitaxially growing the light emitting unit or the like on the main surface side of the crystal growth substrate. Alternatively, a substrate obtained by removing the crystal growth substrate or the like may be used.

  The mounting substrate 20 is made of a thermally conductive material and has a rectangular plate-shaped heat transfer plate 21 on which the LED chip 10 is mounted, and one surface side of the heat transfer plate 21 (upper surface side in FIG. 1A), for example, polyolefin-based. And a wiring board 22 made of a rectangular flexible printed wiring board fixed via a fixing sheet 29 (see FIG. 2). The mounting surface of the LED chip 10 on the heat transfer plate 21 at the center of the wiring board 22 A rectangular window hole 24 for exposing (a part of the one surface) is formed, and the LED chip 10 is mounted on the heat transfer plate 21 via a submount member 30 described later disposed inside the window hole 24. Has been. Therefore, the heat generated in the LED chip 10 is transferred to the submount member 30 and the heat transfer plate 21 without passing through the wiring board 22.

  The above-mentioned wiring board 22 is provided with a pair of conductor patterns 23 and 23 for supplying power to the LED chip 10 on one surface side of an insulating base material 22a made of a polyimide film. A protective layer 26 made of a white resist (resin) covering a portion of the conductive base material 22a where the conductor patterns 23, 23 are not formed is laminated. Therefore, the light emitted from the side surface of the LED chip 10 and incident on the surface of the protective layer 26 is reflected by the surface of the protective layer 26, thereby preventing the light emitted from the LED chip 10 from being absorbed by the wiring substrate 22. Thus, the light output can be improved by improving the light extraction efficiency to the outside. In addition, each conductor pattern 23 and 23 is formed in the outer periphery shape a little smaller than half of the outer periphery shape of the insulating base material 22a. Further, FR4, FR5, paper phenol or the like may be employed as the material of the insulating base material 22a.

  The protective layer 26 is patterned so that two portions of the conductor patterns 23 and 23 are exposed in the vicinity of the window hole 24 of the wiring substrate 22 and one portion of the conductor patterns 23 and 23 is exposed in the peripheral portion of the wiring substrate 22. In each conductor pattern 23, 23, two rectangular portions exposed in the vicinity of the window hole 24 of the wiring substrate 22 constitute a terminal portion 23 a to which the bonding wire 14 is connected. The circular part exposed in the part constitutes the external connection electrode part 23b. The conductor patterns 23 and 23 of the wiring board 22 are constituted by a laminated film of a Cu film, a Ni film, and an Au film.

  By the way, the LED chip 10 is mounted on the heat transfer plate 21 via the above-described submount member 30 that 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. Has been. Here, 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 transferring heat generated in the LED chip 10 to a range wider than the chip size of the LED chip 10 in the heat transfer plate 21. Yes. Therefore, in the light emitting device 1 according to the present embodiment, since the LED chip 10 is mounted on the heat transfer plate 21 via the submount member 30, the heat generated by the LED chip 10 is transferred to the submount member 30 and the heat transfer plate 21. The heat 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 can be relieved.

  As the material of the submount member 30, AlN having a relatively high thermal conductivity and insulation is employed, and the LED chip 10 has the cathode electrode provided on the surface of the submount member 30 on the LED chip 10 side. The electrode pattern (not shown) connected to the cathode electrode and electrically connected to one conductor pattern 23 via a bonding wire 14 made of a metal fine wire (for example, a gold fine wire, an aluminum fine wire, etc.), and the anode The electrode is electrically connected to the other conductor pattern 23 via the bonding wire 14. The LED chip 10 and the submount member 30 may be bonded using, for example, solder such as SnPb, AuSn, SnAgCu, or silver paste, but may be bonded using lead-free solder such as AuSn, SnAgCu. Preferably, when the submount member 30 is Cu and is bonded using AuSn, a pretreatment for forming a metal layer made of Au or Ag in advance on the bonding surface of the submount member 30 and the LED chip 10 is performed. is necessary. Further, the submount member 30 and the heat transfer plate 21 are preferably bonded using, for example, lead-free solder such as AuSn or SnAgCu. However, when bonding using AuSn, the bonding in the heat transfer plate 21 is performed. A pretreatment for forming a metal layer made of Au or Ag in advance on the surface is necessary.

  The material of the submount member 30 is not limited to AlN, and may be any material that has a linear expansion coefficient that is relatively close to 6H—SiC that is a material for a crystal growth substrate and that has a relatively high thermal conductivity. Si, Cu, CuW or the like may be employed. The submount member 30 has the above-described heat conduction function, and the area of the surface of the heat transfer plate 21 on the LED chip 10 side is sufficiently larger than the area of the surface of the LED chip 10 on the heat transfer plate 21 side. Larger is desirable.

  In the light emitting device 1 according to this embodiment, the thickness dimension of the submount member 30 is set so that the surface of the submount member 30 is farther from the heat transfer plate 21 than the surface of the protective layer 26 of the wiring board 22. In addition, light emitted from the LED chip 10 to the side can be prevented from being absorbed by the wiring board 22 through the inner peripheral surface of the window hole 24 of the wiring board 22. In addition, if a reflective film that reflects the light emitted from the LED chip 10 is formed around the bonding portion with the LED chip 10 on the surface of the submount member 30 on the side to which the LED chip 10 is bonded, the LED chip 10 is formed. It is possible to prevent the light radiated from the side surface from being absorbed by the submount member 30 and to further increase the light extraction efficiency to the outside. Here, the reflective film may be formed of, for example, a laminated film of a Ni film and an Ag film.

  As the sealing material that is the material of the sealing portion 50 described above, a silicone resin is used. However, it is not limited to the silicone resin, and for example, an acrylic resin or glass may be used.

  The optical member 60 is a molded product of a translucent material (for example, silicone resin, glass, etc.) and is formed in a dome shape. Here, if the optical member 60 is formed of a molded product of silicone resin, the refractive index difference and the linear expansion coefficient difference between the optical member 60 and the sealing portion 50 can be reduced.

  Further, the optical member 60 has a light emitting surface 60b formed in a convex curved surface shape that does not totally reflect light incident from the light incident surface 60a at the boundary between the light emitting surface 60b and the air layer 80 described above. 10 and the optical axis coincide with each other. Therefore, the light emitted from the LED chip 10 and incident on the light incident surface 60a of the optical member 60 can easily reach the wavelength conversion member 70 without being totally reflected at the boundary between the light emitting surface 60b and the gas layer 80, The total luminous flux can be increased. The optical member 60 is formed to have a uniform thickness along the normal direction regardless of the position.

  In the wavelength conversion member 70, the phosphor particles 71 are dispersed in a translucent medium (for example, silicone resin) having a refractive index smaller than that of the phosphor particles 71 (the phosphor particles 71 are translucent medium 73). As the phosphor particles 71, red phosphor particles and green phosphor particles are employed. Therefore, in the light emitting device 1 according to the present embodiment, the blue light emitted from the LED chip 10 and the light from the red phosphor particles and the green phosphor particles of the wavelength conversion member 70 are emitted from the light emitting surface (outer surface) of the wavelength conversion member 70. ) 70b is emitted and white light can be obtained. Here, as the phosphor particles 71 of the wavelength conversion member 70, for example, yellow phosphor particles may be used instead of the red phosphor particles and the green phosphor particles, or the green phosphor particles and the orange phosphor particles may be used. Particles may be used, and yellow-green phosphor particles and orange phosphor particles may be used. Further, instead of using a blue LED chip that emits blue light as the LED chip 10, an ultraviolet LED chip that emits ultraviolet light is used, and red phosphor particles, green phosphor particles, and blue phosphor particles are used as the phosphor particles 71. You may make it obtain white light by using. Moreover, the translucent medium 73 used as the material of the wavelength conversion member 70 is not limited to a silicone resin, and may be glass, for example. By adopting a silicone resin or glass, general blue light or ultraviolet light is used as excitation light. It is possible to suppress the light transmissive medium 73 from being deteriorated by the excitation light in the case of adopting the above.

  The wavelength converting member 70 has a light incident surface (inner surface) 70 a formed along the light emitting surface 60 b of the optical member 60. Therefore, the distance between the light emitting surface 60b of the optical member 60 and the wavelength conversion member 70 in the normal direction is a substantially constant value regardless of the position of the light emitting surface 60b of the optical member 60. In addition, the wavelength conversion member 70 is shape | molded so that the thickness along a normal line direction may become uniform irrespective of a position. In addition, the wavelength conversion member 70 may be fixed to the mounting substrate 20 with an end edge (periphery of the opening) on the mounting substrate 20 side using, for example, an adhesive (for example, silicone resin, epoxy resin, or the like).

  By the way, as shown in FIGS. 1B and 1C, the wavelength conversion member 70 of the present embodiment has a moth-eye structure portion 74 and a moth-eye structure portion having a fine uneven structure on the surface side of the phosphor particles 71. 74 is provided with an antireflection portion 76 composed of a light-transmitting medium 73 entering between 74 tapered fine protrusions 75, and each of the fine protrusions 75 of the moth-eye-shaped structure portion 74 is more granular than the phosphor particles 71. It is formed by compositing fine particles 72 having a small diameter and a refractive index larger than that of the translucent medium 73 on the surface of the phosphor particles 71 (almost the entire surface of the phosphor particles 71 is formed by a large number of fine particles 72. Coated). Here, when the fine particles 72 are complexed on the surface of the phosphor particles 71, for example, an aqueous solution of the precursor of the fine particles 72, in which the phosphor particles 71 are dispersed, is spray pyrolyzed by a spray pyrolysis method, thereby causing each fluorescence. A large number of fine particles 72 are combined with each of the body particles 71, and the particle size of the fine particles 72 is controlled by adjusting the concentration of the precursor of the fine particles 72 and the spray pyrolysis temperature in the aqueous solution. The method for compositing the fine particles 72 on the surface of the phosphor particles 71 is not limited to the above-described method, and for example, a sol-gel method, a plasma deposition method, or the like may be applied.

The protrusion dimensions of the fine protrusions 75 and the pitch of the fine protrusions 75 in the moth-eye structure 74 are set to λ / n ₃ or less, assuming that the wavelength of the excitation light is λ and the refractive index of the translucent medium 73 is n _3. There is a need. Therefore, for example, when the excitation light is blue light, the wavelength λ of the blue light is 480 nm, the translucent medium 73 is silicone resin, and the refractive index n ₃ is 1.4, the protrusion size and pitch of the fine protrusions 75 are set as follows. It is necessary to set 480 / 1.4≈343 nm or less. When λ = 350 nm to 480 nm and n ₃ = 1.4, the maximum protrusion size and the maximum pitch of the fine protrusions 75 are appropriately set within a range of 250 nm to 343 nm. You only have to set it.

By the way, as shown in FIG. 3A, the moth-eye structure portion 74 in the antireflection portion 76 on the surface side of the phosphor particles 71 has a fine concavo-convex structure in which conical fine protrusions 75 are arranged. The refractive index of the translucent medium 73 entering between the fine protrusions 75 is n ₃ , the refractive index of the phosphor particles 71 is n _1, and the refractive index of the fine protrusions 75 is the same as the refractive index of the phosphor particles 71. If there is, the effective refractive index of the antireflection part 76 is such that the refractive index n ₁ of the phosphor particles 71 and the translucent medium 73 in the normal direction of the surface of the phosphor particles 71 as shown in FIG. continuously varies between the refractive index n ₃ of the.

However, it is difficult to form the moth-eye structure portion 74 having a fine concavo-convex structure as shown in FIG. 3A on the surface side of the phosphor particles 71. In the wavelength conversion member 70 of the present embodiment, FIG. (B), (c) has a fine concavo-convex structure in which tapered fine protrusions 75 are arranged, and the refractive index n ₂ of the fine particles 72 is made the same as the refractive index n ₁ of the phosphor particles 71. For example, the effective refractive index of the antireflection part 76 is such that the refractive index n ₁ of the phosphor particles 71 and the refractive index of the translucent medium 73 are as shown in FIG. 1 (d) in the normal direction of the surface of the phosphor particles 71. continuously changes between n _3. The center particle diameter d ₅₀ of the fine particles 72 is preferably set in the range of λ / (10n ₃ ) ≦ d ₅₀ ≦ λ / n ₃ .

Further, regarding the phosphor particles 71 in the wavelength conversion member 70, as the red phosphor particles, phosphor particles having a composition of CaAlSiN ₃ : Eu ²⁺ , a refractive index of 2.0, and a center particle diameter d ₅₀ of 10 μm are used. As the particles, phosphor particles having a composition of CaSc ₂ O ₄ : Ce ³⁺ , a refractive index of 1.9, and a center particle diameter d ₅₀ of 8 μm are used. However, the present invention is not limited to these compositions. For example, the composition may be (Ca, Sr) AlSiN ₃ : Eu ²⁺ , CaS: Eu ²⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ^2+, etc., and green phosphor particles as, for example, _{composition, Ca 3 Sc 2 Si 3 O} 12: Ce 3+, (Ca, Sr, Ba) Al 2 O 4: Eu 2+, SrGa 2 S 4: using such things as ^{Eu 2+} Good. Further, when yellow phosphor particles are employed as the phosphor particles 71, for example, the composition is Y ₃ Al ₅ O ₁₂ : Ce ³⁺ , (Ca, Sr, Ba, Zn) ₂ SiO ₄ : Eu ²⁺ or the like. When yellow-green phosphor particles and orange phosphor particles are adopted as the phosphor particles 71, for example, the composition of the yellow-green phosphor particles is (Ba, Sr) ₂ SiO ₄ : may be used those such as Eu ^2+, as orange phosphor particles, ^{_{composition, Sr 3 SiO 5: Eu 2+}} , Ca 0.7 Sr 0.3 AlSiN 3: may be used in an as such ^{Eu 2+.} The phosphor particles 71 having a larger central particle diameter d ₅₀ have a smaller defect density and less energy loss, resulting in higher luminous efficiency. From the viewpoint of luminous efficiency, the phosphor particles 71 should have a central particle diameter d ₅₀ of 5 μm or more. It is preferable to adopt.

In the present embodiment, as the material of the fine particles 72, a metal oxide (for example, ZrO ₂ ) that is transparent to the excitation light to the phosphor particles 71 and the converted light from the phosphor particles 71 is employed. The fine particles 72 are transparent to the excitation light to the phosphor particles 71 and the converted light from the phosphor particles 71, and the excitation light and the converted light can be prevented from being absorbed by the fine particles 72. Here, if the refractive index of the fine particles 72 and n _2, as the particles 72, it is preferable that the refractive index n ₂ is adopted as the refractive index n ₁ or more of the phosphor particles 71, the refractive index n ₂ is 2 .05 ZrO ₂ is employed, but not limited to ZrO ₂ , for example, TiO ₂ having a refractive index n ₂ of 2.3 to 2.55 may be employed. However, the refractive index n ₂ of the fine particles 72 is more preferably the same as the refractive index of the phosphor particles 71. The material of the fine particles 72 may be appropriately selected from various metal oxides according to the refractive index n ₁ of the phosphor particles 71 and the refractive index n ₃ of the translucent medium 73. For example, SiO ₂ , Al ₂ O ₃ , Y ₂ O _3, or the like can also be employed. Here, the refractive index of SiO ₂ is 1.46, the refractive index of Al ₂ O ₃ is 1.63, and the refractive index of Y ₂ O ₃ is 1.87. For example, the phosphor particles 71 are YAG: Ce ^3+. When the refractive index n ₁ is 1.83, the translucent medium 73 is a silicone resin, and the refractive index n ₃ is 1.4, the fine particles 72 have a refractive index n ₂ of 1.87. by employing the Y ₂ O _3, comprising a refractive index _{n 2} of the refractive index _{n 1} and the fine particles 72 of phosphor particles 71 and is substantially the same.

  In the wavelength conversion member 70 of the present embodiment described above, on the surface side of the phosphor particles 71, the moth-eye structure portion 74 having a fine concavo-convex structure and the transparent fine protrusions 75 of the moth-eye structure portion 74 that have entered the gap are formed. The antireflection part 76 comprised with the optical medium 73 is provided, and each fine protrusion 75 of the moth-eye structure part 74 has a smaller particle diameter than the fluorescent substance particle 71, and a refractive index larger than the translucent medium 73. Since the fine particles 72 are formed on the surface of the phosphor particles 71, the incident efficiency of the excitation light to the phosphor particles 71 is further improved and the conversion from the phosphor particles 71 is suppressed by suppressing Fresnel reflection. The light extraction efficiency can be further improved (the reflection loss of the excitation light can be reduced and the reflection loss of the converted light can be reduced). As a result, the light extraction efficiency of the wavelength conversion member 70 can be reduced. Improved, the light emitting device 1 to improve the light extraction efficiency to the entire outside can be improved luminous flux. Therefore, the light emitting device 1 of the present embodiment uses the above-described wavelength conversion member 70 as a color conversion member that converts and emits a part of the light emitted from the LED chip 10 into light having a longer wavelength than the light. Therefore, it is possible to further improve the incident efficiency of the excitation light to the phosphor particles 71 in the color conversion member and further improve the extraction efficiency of the converted light from the phosphor particles 71, thereby increasing the light output. Can be planned.

Further, in the wavelength conversion member 70 of the present embodiment, when the refractive index n ₂ of the fine particles 72 is the same as the refractive index n _{1 of} the phosphor particles 71, the antireflection portion 76 in the normal direction of the surface of the phosphor particles 71. since the effective refractive index varies continuously between the refractive index n ₂ of the refractive index n ₁ and the transparent medium 73 of the phosphor particles 71, improvement in efficiency of incidence of the excitation light to the phosphor particles 71 and the If the efficiency of extracting converted light from the phosphor particles 71 can be improved and the refractive index n ₂ of the fine particles 72 is made larger than the refractive index n ₁ of the phosphor particles 71, the refractive index n ₂ of the fine particles 72 can be increased. Compared with a case where the refractive index is smaller than the refractive index n _{1 of} 71 (that is, when n ₁ > n ₂ > n ₃ ), the converted light from the phosphor particles 71 is easily incident into the fine particles 72. The extraction efficiency of the converted light from the can be improved.

Example 1
In this example, in the light emitting device 1 of Embodiment 1, a blue LED chip having an emission peak wavelength of 460 nm is adopted as the LED chip 10, and the refractive index of the wavelength conversion member 70 is 1.4 as the translucent medium 73. As a red phosphor particle, the composition is CaAlSiN ₃ : Eu ²⁺ with a refractive index of 2.0 and a center particle size d ₅₀ of 10 μm as a phosphor particle and a green phosphor particle. Phosphor particles having a composition of CaSc ₂ O ₄ : Ce ³⁺ and a refractive index of 1.9 and a center particle diameter d ₅₀ of 8 μm are used, and ZrO ₂ having a refractive index n ₂ of 2.05 is used as the fine particles 72. by the aqueous solution of zirconium oxynitrate an aqueous solution of a precursor of fine particles 72 dispersed phosphor particles 71 thermally spray drying, median particle size d to each of the phosphor particles 71 ₀ microparticles 72 100nm is complexed, as compared with Comparative Example 1 using the wavelength conversion member 70 that is not complexed to particles 72 to the phosphor particles 71, the light beam of the light emitting device 1 is improved by about 7%.

(Embodiment 2)
The basic configuration of the light emitting device 1 of the present embodiment shown in FIG. 4A is the same as that of the first embodiment. With respect to the wavelength conversion member 70, as shown in FIGS. The entire surface is coated with a metal oxide layer 77 having substantially the same refractive index as that of the phosphor particles 71, and the fine particles 72 are combined with the phosphor particles 71 through the metal oxide layer 77. Just do it. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

The material of the metal oxide layer 77 may be appropriately selected from various metal oxides according to the refractive index of the phosphor particles 71. For example, ZrO ₂ or Y ₂ O ₃ may be employed. Moreover, in this embodiment, although the thickness of the metal oxide layer 77 is set in the range of 100 nm-150 nm, this numerical value is an example and it does not specifically limit it.

  Here, when the fine particles 72 are combined on the surface side of the phosphor particles 71, first, the surface of the phosphor particles 71 is coated with the metal oxide layer 77, and then the fine particles 72 are combined. Here, when the metal oxide layer 77 is coated on the surface of the phosphor particles 71, for example, a precursor slurry of the metal oxide layer 77 in which a predetermined amount of the phosphor particles 71 is dispersed is thermally spray-dried. A metal oxide layer 77 is formed on the surface of each phosphor particle 71. In order to obtain a denser metal oxide layer 77, heat treatment may be performed as necessary. Thereafter, a slurry of the precursor of the fine particles 72 in which the phosphor particles 71 coated with the metal oxide layer 77 are dispersed is thermally spray-dried, so that the surface of each phosphor particle 71 passes through the metal oxide layer 77. In this slurry, the particle size of the fine particles 72 is controlled by adjusting the concentration of the precursor of the fine particles 72 and the spray heat drying temperature in the slurry. The method for compositing the fine particles 72 on the surface side of the phosphor particles 71 is not limited to the above-described method, and for example, a sol-gel method, a fluidized bed coating method, a plasma deposition method, or the like may be applied.

Here, as in the first embodiment, the refractive index of the fine particles 72 is n ₂ , the refractive index of the phosphor particles 71 is n ₁ , the refractive index of the translucent medium 73 is n _3, and the refractive index of the metal oxide layer 77. Is n ₄ , the effective refractive index of the antireflection portion 76 is such that the refractive index n ₂ of the fine particles 72 and the translucent medium 73 in the normal direction of the surface of the phosphor particles 71 as shown in FIG. continuously varies between the refractive index n ₃ of the. Refractive index n ₂ of the fine particles 72 is is set to be higher than the refractive index n ₁ of the phosphor particles 71, are substantially identical to the refractive index n ₁ of the refractive index n ₂ and the phosphor particles 71 of the particulate 72 It is preferable that they are the same. Further, the refractive index n ₄ of the metal oxide layer 77 is substantially the same as the refractive index n ₁ of the phosphor particles 71, but in FIG. 4D, the refractive index n ₄ of the metal oxide layer 77 is fluorescent. The upper limit value of the refractive index n ₄ regarded as substantially the same as the refractive index n ₁ of the body particle 71 is shown as n _4max and the lower limit value is shown as n 4 _min .

Here, in order to define a range in which the refractive index n ₄ of the metal oxide layer 77 is considered to be substantially the same as the refractive index n ₁ of the phosphor particles 71, the refractive index n ₁ of the phosphor particles 71 and the metal oxide The ratio ({| n ₁ −n ₄ | / n ₁ } × 100) of the refractive index difference (| n ₁ −n ₄ |) with respect to the refractive index n ₁ of the phosphor particles 71 to the refractive index n ₄ of the layer 77 FIG. 5 shows the result of simulating the relationship with the relative reflection loss (relative value of the reflection loss considering only the regular reflection component) at the interface (refractive index interface) between the metal oxide layer 77 and the phosphor particles 71. As can be seen from FIG. 5, when the ratio of the refractive index difference to the refractive index n ₁ is 22% or more, the relative reflection loss at the interface (refractive index interface) between the metal oxide layer 77 and the phosphor particles 71 is 1%. Exceed. On the other hand, in the light-emitting device 1 of Example 1 described above, the increase rate of the light extraction efficiency with respect to Comparative Example 1 is 7%, so the value of 1% of the relative reflection loss is not negligible. Therefore, when the ratio of the refractive index difference to the refractive index n ₁ is 15% or less (relative reflection loss is 0.5% or less), the refractive index n ₄ of the metal oxide layer 77 is changed to the refractive index of the phosphor particles 71. and it is regarded as n ₁ is substantially the same. Incidentally, when the refractive index n ₂ of the fine particles 72 is larger than the refractive index n ₁ of the phosphor particles 71, to reduce the refractive index difference between the refractive index n ₄ of the refractive index n ₂ and the metal oxide layer 77 of microparticle 72 from the viewpoint, the range of the refractive index n ₄ of the refractive index n ₄ regarded as substantially the same as the refractive index n ₁ of the phosphor particles 71 of the metal oxide layer 77 is preferably n _4> n _1.

In the wavelength conversion member 70 of the present embodiment described above, the entire surface of the phosphor particle 71 is coated with the metal oxide layer 77 having substantially the same refractive index n ₄ as the phosphor particle 71, and the phosphor particle Since the metal oxide layer 77 is interposed between the fine particles 71 and the fine particles 72, it is possible to prevent moisture from the outside from reaching the phosphor particles 71 and to improve moisture resistance (humidity). Therefore, the degree of freedom in selecting the material of the phosphor particles 71 is increased, and the refractive index n ₄ of the metal oxide layer 77 is increased. By being substantially the same as the refractive index n ₁ of the phosphor particles 71, it is possible to suppress a decrease in the antireflection effect of the moth-eye structure portion 74 and at the interface between the phosphor particles 71 and the metal oxide layer 77. Excitation light reflection It can be suppressed.

  The light emitting device 1 of the present embodiment also has the above-described wavelength as a color conversion member that converts and emits a part of light emitted from the LED chip 10 into light having a longer wavelength than the light, as in the first embodiment. Since the conversion member 70 is used, the incident efficiency of the excitation light to the phosphor particles 71 in the color conversion member and the extraction efficiency of the converted light from the phosphor particles 71 can be further improved. High output can be achieved.

(Example 2)
In this example, in the light emitting device 1 of the second embodiment, a blue LED chip having an emission peak wavelength of 460 nm is adopted as the LED chip 10, and the refractive index of the wavelength conversion member 70 is 1.4 as the translucent medium 73. Silicone resin and phosphor particles 71, green phosphor particles having a composition of CaSc ₂ O ₄ : Ce ³⁺ with a refractive index of 1.9 and a center particle size d ₅₀ of 8 μm, orange phosphor particles As the metal oxide layer 77, phosphor particles having a composition of Ca _0.7 Sr _0.3 AlSiN ₃ : Eu ²⁺ with a refractive index of 2.1 and a center particle diameter d ₅₀ of 10 μm are employed. the ZrO ₂ of 05 employed, the refractive index _{n 2} as fine particles 72 have adopted ZrO ₂ of 2.05.

Here, when the metal oxide layer 77 is coated on the surface of the phosphor particles 71 when the wavelength conversion member 70 is manufactured, for example, a predetermined amount of each of the green phosphor particles and the orange phosphor particles in n-butanol. The slurry obtained by mixing and stirring the phosphor particles 71 (predetermined amount of green phosphor particles or predetermined amount of orange phosphor particles), zirconium tetraisopropoxide, and a small amount of water is heat spray dried, and then 350 By performing heat treatment at ° C., a metal oxide layer 77 composed of a ZrO ₂ layer having a thickness of about 100 nm to 150 nm is formed on the surface of each phosphor particle 71. Further, when the fine particles 72 are compounded on the surface side of the phosphor particles 71, the green phosphor particles coated with the metal oxide layer 77 and the orange phosphor particles coated with the metal oxide layer 77 are each n -A predetermined amount of phosphor particles 71 coated with the above metal oxide layer 77 in butanol (a predetermined amount of green phosphor particles coated with the metal oxide layer 77 or a metal oxide layer 77 is coated). The slurry obtained by mixing and stirring a predetermined amount of the orange phosphor particles) and the zirconium oxide sol is subjected to thermal spray drying, whereby the center particles are disposed on the surface side of each phosphor particle 71 via the metal oxide layer 77. Fine particles 72 made of a large number of ZrO ₂ fine particles having a diameter d ₅₀ of about 100 nm to 150 nm are combined. Thereafter, the phosphor particles 71 in which the fine particles 72 are combined are dispersed in a silicone resin having a refractive index of 1.4 and formed into a dome shape, thereby forming the wavelength conversion member 70. Further, as Comparative Example 2, a light emitting device having the same configuration as that of Example 2 and having no metal oxide layer 77 and fine particles 72 was produced.

  About the Example 2 and the comparative example 2 which were demonstrated above, the reliability acceleration test was done on the test conditions of temperature 85 degreeC, relative humidity 85% RH, and intermittent electricity supply (30-minute lighting, 30-minute light-off cycle). Table 1 below shows the results of measuring the total luminous flux before the test and the total luminous flux after 1000 hours had elapsed from the start of the test. In Table 1, relative values normalized with the luminous flux before the test of Comparative Example 2 as 100 are shown.

  From Table 1, in the light-emitting device 1 of Example 2, the luminous flux before the start of the test is improved by 7% compared to Comparative Example 2, and the degradation of the luminous flux after 1000 hours from the start of the test is also reduced. It can be seen that high output and moisture resistance can be improved.

(Example 3)
In this example, in the light emitting device 1 of the second embodiment, a blue LED chip having an emission peak wavelength of 460 nm is adopted as the LED chip 10, and the refractive index of the wavelength conversion member 70 is 1.4 as the translucent medium 73. A phosphor resin that employs a silicone resin and has a composition of (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ with a refractive index of 1.9 and a center particle diameter d ₅₀ of 10 μm as yellow-green phosphor particles with respect to the phosphor particles 71. As the orange phosphor particles, phosphor particles having a composition of Sr ₃ SiO ₅ : Eu ²⁺ and a refractive index of 1.9 and a center particle diameter d ₅₀ of 10 μm are adopted, and the metal oxide layer 77 has a refractive index of 1.87. adopted for _Y 2 _{O 3,} the refractive index _{n 2} as fine particles 72 have adopted _Y 2 _{O 3} of 1.87.

Here, when the metal oxide layer 77 is coated on the surface of the phosphor particle 71 when the wavelength conversion member 70 is manufactured, for example, each of the yellow-green phosphor particle and the orange phosphor particle is placed in n-butanol. A slurry obtained by mixing and stirring a predetermined amount of phosphor particles 71 (a predetermined amount of yellow-green phosphor particles or a predetermined amount of orange phosphor particles), yttrium triisopropoxide, and a small amount of water is heat spray dried, Next, by performing heat treatment at 300 ° C., a metal oxide layer 77 made of a Y ₂ O ₃ layer having a thickness of about 100 nm to 150 nm is formed on the surface of each phosphor particle 71. Further, when the fine particles 72 are compounded on the surface side of the phosphor particles 71, each of the yellow phosphor particles coated with the metal oxide layer 77 and the orange phosphor particles coated with the metal oxide layer 77 is divided into n -Predetermined amount of phosphor particles 71 coated with the above-described metal oxide layer 77 in butanol (predetermined amount of yellow-green phosphor particles coated with the metal oxide layer 77, or coated with the metal oxide layer 77) A predetermined amount of the orange phosphor particles) and a slurry obtained by mixing and stirring the yttrium oxide sol are thermally spray-dried to center each phosphor particle 71 through the metal oxide layer 77 on the surface side. Fine particles 72 composed of a large number of Y ₂ O ₃ fine particles having a particle diameter d ₅₀ of about ₁₀₀ nm to 150 nm are combined. Thereafter, the phosphor particles 71 in which the fine particles 72 are combined are dispersed in a silicone resin having a refractive index of 1.4 and formed into a dome shape, thereby forming the wavelength conversion member 70. Further, as Comparative Example 3, a light emitting device having the same configuration as that of Example 3 and having no metal oxide layer 77 and fine particles 72 was produced.

  About the Example 3 demonstrated above and the above-mentioned comparative example 3, the reliability acceleration test was done on the test conditions of temperature 85 degreeC, relative humidity 85% RH, and intermittent electricity supply (30-minute lighting, 30-minute light-off cycle). The results of measuring the luminous flux before the test and the luminous flux after 1000 hours from the start of the test are shown in Table 2 below. In Table 2, relative values normalized with the luminous flux before the test of Comparative Example 3 as 100 are shown.

  From Table 2, in the light emitting device 1 of Example 3, the light flux before the start of the test is improved by 10% and the deterioration of the light flux after 1000 hours from the start of the test is less than that of Comparative Example 3. It can be seen that high output and moisture resistance can be improved.

(Embodiment 3)
The basic configuration of the light emitting device 1 of the present embodiment shown in FIG. 6A is the same as that of the first embodiment. With respect to the wavelength conversion member 70, as shown in FIGS. 73 has a light-transmitting base material (for example, silicone resin, glass, etc.) 73a in which phosphor particles 71 in which fine particles 72 are combined are scattered on the surface, and substantially the same refractive index as the light-transmitting base material 73a. The only difference is that the composite particles of the phosphor particles 71 and the fine particles 72 and the metal oxide layer 73b constituting a part of the antireflection portion 76 are interposed between the translucent base material 73a. is there. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

The material of the metal oxide layer 73b may be appropriately selected from various metal oxides according to the refractive index of the translucent base material 73a. For example, SiO ₂ may be employed. Moreover, in this embodiment, although the thickness of the metal oxide layer 73b is set in the range of 100 nm-150 nm, this numerical value is an example and it does not specifically limit it.

  Here, when the wavelength conversion member 70 is manufactured, a slurry of the precursor of the fine particles 72 in which the phosphor particles 71 are dispersed is thermally spray-dried, so that a large number of fine particles 72 are combined on the surface of each phosphor particle 71. Then, after forming the metal oxide layer 73b by, for example, a sol-gel method, the phosphor particles 71 coated with the metal oxide layer 73b are applied to a silicone resin or glass that is a material of the translucent base material 73a. Dispersed and formed into a dome shape. The method for forming the metal oxide layer 73b is not limited to the sol-gel method, and for example, a plasma deposition method may be used. In order to obtain a denser metal oxide layer 73b, heat treatment may be performed as necessary.

Here, as in the first embodiment, the refractive index of the fine particles 72 is n ₂ , the refractive index of the phosphor particles 71 is n ₁ , the refractive index of the translucent base material 73 a is n ₃ , and the refractive index of the metal oxide layer 73 b. If the rate is n ₄ , the effective refractive index of the antireflection part 76 is such that the refractive index n ₂ of the fine particles 72 and the metal oxide layer in the normal direction of the surface of the phosphor particles 71 as shown in FIG. continuously changes between 73b refractive index n ₄ of the. Refractive index n ₂ of the fine particles 72 is is set to be higher than the refractive index n ₁ of the phosphor particles 71, are substantially identical to the refractive index n ₁ of the refractive index n ₂ and the phosphor particles 71 of the particulate 72 It is preferable that they are the same. Further, the refractive index n ₄ of the metal oxide layer 73b is substantially the same as the refractive index n ₃ of the translucent base material 73a, but in FIG. 6D, the refractive index n ₄ of the metal oxide layer 73b is related. The upper limit value of the refractive index n ₄ regarded as substantially the same as the refractive index n ₃ of the translucent base material _{73 a} is shown as n _4max and the lower limit value is shown as n 4 _min .

Here, in order to define the range considered a refractive index n ₄ of the metal oxide layer 73b and is substantially the same as the refractive index n ₃ of the light-transmitting base material 73a, the refractive index n ₃ of the light-transmitting base material 73a the refractive index difference between the refractive index _{n 4} of the metal oxide layer 73b proportion to the refractive index _{n 3} of the light-transmitting base material 73a of _{({(| | n 3 -n} 4) | n 3 -n 4 | / n ₃ } × 100) and the relative reflection loss (relative value of the reflection loss considering only the specular reflection component) at the interface (refractive index interface) between the translucent base material 73a and the metal oxide layer 73b. The results are shown in FIG. As can be seen from FIG. 7, 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 base material 73a and the metal oxide layer 73b is 1. %. On the other hand, in the light-emitting device 1 of Example 1 described above, the increase rate of the light extraction efficiency with respect to Comparative Example 1 is 7%, so the value of 1% of the relative reflection loss is not negligible. Therefore, when the ratio of the refractive index difference to the refractive index n ₃ is 15% or less (relative reflection loss is 0.5% or less), the refractive index n ₄ of the metal oxide layer 73b is changed to that of the translucent base material 73a. and it is considered a refractive index n ₃ and is substantially the same.

In the wavelength conversion member 70 of the present embodiment described above, the translucent medium 73 includes the translucent base material 73a in which the phosphor particles 71 in which the fine particles 72 are combined on the surface are scattered, and the translucent base material 73a. Oxide layer having a refractive index n ₄ that is substantially the same as that of the anti-reflection portion 76 and interposed between the composite particles of the phosphor particles 71 and the fine particles 72 and the translucent base material 73a. 73b, the gaps between the fine particles 72 are coated with the metal oxide layer 73b on the surface side of the phosphor particles 71, and moisture from the outside can be prevented from reaching the phosphor particles 71. Since the moisture resistance can be improved (deterioration of the properties of the phosphor particles 71 due to the influence of humidity), the degree of freedom in selecting the material of the phosphor particles 71 is increased, and Refractive index n of metal oxide layer 73b ₄ By is substantially the same as the refractive index n ₃ of the light-transmitting base material 73a, can suppress the reflection of the excitation light it is possible to suppress a decrease in anti-reflection effect of the moth-eye-like structure 74.

  Further, in the wavelength conversion member 70 of the present embodiment, the translucent base material 73a is made of silicone resin or glass. Therefore, when general blue light or ultraviolet light is used as excitation light for the phosphor particles 71, the translucent base material 73a is transparent. The optical medium 73 can be prevented from being deteriorated by the excitation light.

  The light emitting device 1 of the present embodiment also has the above-described wavelength as a color conversion member that converts and emits a part of light emitted from the LED chip 10 into light having a longer wavelength than the light, as in the first embodiment. Since the conversion member 70 is used, the incident efficiency of the excitation light to the phosphor particles 71 in the color conversion member and the extraction efficiency of the converted light from the phosphor particles 71 can be further improved. High output can be achieved.

Example 4
In this example, in the light emitting device 1 of the third embodiment, a blue LED chip having an emission peak wavelength of 460 nm is adopted as the LED chip 10, and the refractive index of the wavelength conversion member 70 is 1.4 as the translucent base material 73a. As a green phosphor particle, a phosphor particle having a composition of CaSc ₂ O ₄ : Ce ³⁺ with a refractive index of 1.9 and a center particle size d ₅₀ of 8 μm, a red phosphor As the particles, phosphor particles having a composition of Ca _0.7 Sr _0.3 AlSiN ₃ : Eu ²⁺ with a refractive index of 2.1 and a center particle diameter d ₅₀ of 10 μm are adopted, and the refractive index of the metal oxide layer 73b is 1. .5 SiO ₂ and ZrO ₂ having a refractive index n ₂ of 2.05 are adopted as the fine particles 72.

Here, in the production of the wavelength conversion member 70, when the fine particles 72 are combined on the surface of the phosphor particles 71, a predetermined amount of the phosphor particles 71 (in the isopropanol for each of the green phosphor particles and the red phosphor particles) ( A slurry obtained by mixing and stirring a predetermined amount of green phosphor particles or a predetermined amount of red phosphor particles) and a zirconium oxide sol is subjected to thermal spray drying, whereby a central particle is formed on the surface of each phosphor particle 71. Fine particles 72 made of a large number of ZrO ₂ fine particles having a diameter d ₅₀ of 100 nm are combined. Then, when coating the metal oxide layer 73b on the surface side of the phosphor particles 71, for example, for each of the green phosphor particles combined with the fine particles 72 and the red phosphor particles combined with the fine particles 72, isopropanol Among them, a predetermined amount of phosphor particles 71 (predetermined amount of green phosphor particles or predetermined amount of red phosphor particles), TEOS (tetraethylorthosilicate), water, hydrochloric acid as a catalyst at 60 ° C. for a predetermined time (6 The slurry obtained by mixing and stirring for only (time) is filtered, washed, and subjected to heat treatment at 300 ° C., thereby forming the metal oxide layer 73b composed of the SiO ₂ layer. Thereafter, the phosphor particles 71, in which the fine particles 72 are combined and coated with the metal oxide layer 73b, are dispersed in a silicone resin having a refractive index of 1.4 and formed into a dome shape, thereby forming the wavelength conversion member 70. doing.

(Example 5)
The basic configuration of the light emitting device 1 of this example is the same as that of the first embodiment, and only the point that the metal oxide layer 73b is not formed is different from the example 4.

  For Example 4 described above, Example 5 in which the metal oxide layer 73b is not formed, and Comparative Example 2 described above, temperature 85 ° C., relative humidity 85% RH, intermittent energization (30 minutes on, 30 minutes off) Acceleration test was performed under the test conditions of (cycle). The results of measuring the luminous flux before the test and the luminous flux after 1000 hours from the start of the test are shown in Table 3 below. In Table 3, relative values normalized with the luminous flux before the test of Comparative Example 2 as 100 are shown.

  From Table 3, in the light-emitting devices 1 of Examples 4 and 5, the luminous flux before the start of the test is improved by 7% compared to Comparative Example 2, and the degradation of the luminous flux after 1000 hours from the start of the test is also reduced. It can be seen that high output and moisture resistance can be improved. Further, from the comparison between Example 4 and Example 5, the moisture resistance is improved in Example 4 including the metal oxide layer 73b as compared with Example 5 including no metal oxide layer 73b. I understand that.

(Example 6)
In this example, in the light emitting device 1 of the third embodiment, a blue LED chip having an emission peak wavelength of 460 nm is adopted as the LED chip 10, and the refractive index of the wavelength conversion member 70 is 1.4 as the translucent base material 73a. A phosphor having a composition of (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ , a refractive index of 1.9, and a center particle diameter d ₅₀ of 10 μm as a yellow-green phosphor particle. The phosphor particles having a composition of Sr ₃ SiO ₅ : Eu ²⁺ and a refractive index of 1.9 and a center particle diameter d ₅₀ of 10 μm are employed as the orange phosphor particles, and the refractive index of the metal oxide layer 73b is 1. 5 of SiO ₂ is adopted, the refractive index _{n 2} as fine particles 72 have adopted _Y 2 _{O 3} of 1.87.

Here, when the fine particles 72 are combined on the surface of the phosphor particles 71 when the wavelength conversion member 70 is manufactured, a predetermined amount of phosphor in n-butanol is used for each of the yellow-green phosphor particles and the orange phosphor particles. A slurry obtained by mixing and stirring particles 71 (a predetermined amount of yellow-green phosphor particles or a predetermined amount of orange phosphor particles), yttrium triisopropoxide, and a small amount of water is subjected to spray pyrolysis by spray pyrolysis. As a result, fine particles 72 composed of a large number of Y ₂ O ₃ fine particles having a center particle diameter d ₅₀ of about 100 nm to 150 nm are combined on the surface of each phosphor particle 71. Thereafter, in coating the metal oxide layer 73b on the surface side of the phosphor particles 71, for example, for each of the yellow-green phosphor particles combined with the fine particles 72 and the orange phosphor particles combined with the fine particles 72, In isopropanol, a predetermined amount of phosphor particles 71 (a predetermined amount of yellow-green phosphor particles or a predetermined amount of orange phosphor particles), TEOS (tetraethylorthosilicate), water, and hydrochloric acid as a catalyst at 60 ° C. for a predetermined time. The slurry obtained by mixing and stirring for (6 hours) is filtered, washed, and subjected to heat treatment at 300 ° C. to form a metal oxide layer 73b made of a SiO ₂ layer. Thereafter, the phosphor particles 71, in which the fine particles 72 are combined and coated with the metal oxide layer 73b, are dispersed in a silicone resin having a refractive index of 1.4 and formed into a dome shape, thereby forming the wavelength conversion member 70. doing.

(Example 7)
The basic configuration of the light emitting device 1 of this example is the same as that of the first embodiment, and only the point that the metal oxide layer 73b is not formed is different from the example 6.

  For Example 6 described above, Example 7 in which the metal oxide layer 73b is not formed, and Comparative Example 3 described above, temperature 85 ° C., relative humidity 85% RH, intermittent energization (30 minutes on, 30 minutes off) Acceleration test was performed under the test conditions of (cycle). Table 4 below shows the results of measuring the luminous flux before the test and the luminous flux after 1000 hours had elapsed from the start of the test. In Table 4, relative values normalized with the luminous flux before the test of Comparative Example 3 as 100 are shown.

  From Table 4, in the light-emitting devices 1 of Examples 6 and 7, the luminous flux before the start of the test is improved by 10% compared to Comparative Example 3, and the degradation of the luminous flux after 1000 hours from the start of the test is also reduced. It can be seen that high output and moisture resistance can be improved. Moreover, from the comparison between Example 6 and Example 7, the moisture resistance is improved in Example 6 including the metal oxide layer 73b compared to Example 7 not including the metal oxide layer 73b. I understand that.

  By the way, the shape of the wavelength conversion member 70 and the structure of the light emitting device 1 to which the wavelength conversion member 70 is applied are not limited to the structures of the above embodiments and the above examples, and the shape of the wavelength conversion member 70 is a dome shape. For example, it may be a sheet-like shape.

DESCRIPTION OF SYMBOLS 1 Light-emitting device 10 LED chip 70 Wavelength conversion member (color conversion member)
71 Phosphor Particles 72 Fine Particles 73 Translucent Medium 73a Translucent Base Material 73b Metal Oxide Layer 74 Mosaic Structure 75 Fine Projection 76 Antireflection Unit 77 Metal Oxide Layer

Claims (8)

A wavelength conversion member in which phosphor particles are scattered in a translucent medium having a refractive index smaller than that of the phosphor particles, and a moth-eye structure and a moth-eye structure having a fine uneven structure on the surface side of the phosphor particles Each of the fine projections of the moth-eye structure is smaller in size than the phosphor particles and has the light-transmitting property. It is formed by combining fine particles having a refractive index larger than that of the fluorescent medium with the phosphor particles on the surface side of the phosphor particles, and the refractive index of the fine particles is the same as the refractive index of the phosphor particles. Wavelength conversion member to be used. A wavelength conversion member in which phosphor particles are scattered in a translucent medium having a refractive index smaller than that of the phosphor particles, and a moth-eye structure and a moth-eye structure having a fine uneven structure on the surface side of the phosphor particles Each of the fine projections of the moth-eye structure is smaller in size than the phosphor particles and has the light-transmitting property. than sex medium will be formed by conjugating the phosphor particles in the surface side of the phosphor particles larger particle refractive index, the refractive index of the fine particles and Okiiko than the refractive index of the fluorescent particles wavelength conversion member characterized. The fine particles may claim 1 or claim 2 Symbol mounting features that you become formed of a transparent metal oxide with respect to converted light from the excitation light and the fluorescent particles to the phosphor particles Wavelength conversion member. The entire surface of the phosphor particles is coated with a metal oxide layer having substantially the same refractive index as the phosphor particles, and the fine particles are combined with the phosphor particles through the metal oxide layer. becomes, the said substantially identical, wherein n ₁ the refractive index of the phosphor _particles, when the refractive index of the metal oxide layer and the n _4, the refractive index difference | to the refractive index n ₁ of _| n 1 _-n 4 ratio _{{| n 1 -n 4 | /} n 1} × 100 is, according to claim 1 or claim 2 Symbol placement wavelength conversion member, characterized in that the case for 15% or less. The translucent medium has a translucent matrix in which the phosphor particles in which the fine particles are combined on the surface are scattered, and the phosphor particles having substantially the same refractive index as the translucent matrix. And a metal oxide layer constituting a part of the antireflection part interposed between the composite particles of the fine particles and the translucent base material, and the substantially same means the translucent base When the refractive index of the material is n ₃ and the refractive index of the metal oxide layer is n ₄ , the ratio of the refractive index difference | n ₃ −n ₄ | to the refractive index n ₃ {| n ₃ −n ₄ | / n _3} × 100 is, according to claim 1 or claim 2 Symbol placement wavelength conversion member, characterized in that the case for 15% or less. The wavelength conversion member according to any one of claims 1 to 4, wherein the translucent medium is a silicone resin or glass . The light-transmitting base material, the wavelength converting member according to claim 5 Symbol mounting, characterized in that a silicone resin or glass. An LED chip, and a color conversion member that converts a part of light emitted from the LED chip into light having a longer wavelength than the light and emits the light, and the color conversion member is any one of claims 1 to 7. or the light emitting device you characterized by using a wavelength conversion member according to item 1.

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