JP2007149909A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device having less color uneveness, using a light-emitting device. <P>SOLUTION: This light emitting device 100 has the light-emitting element 10, a first lead 20 on which the light-emitting element 10 is arranged, a first resin 31 for covering the light-emitting device 10, and a second resin 41 for covering the first resin 31. A phosphor 30, having a mean particle diameter of 1 μm to 200 μm for absorbing the light from the light-emitting element 10 and effecting the wavelength conversion thereof is mixed into the first resin 31, and a nanophosphor 40 having a mean particle diameter of 0.1 nm to 100 nm for absorbing the light from the light-emitting device 10 and effecting the wavelength conversion thereof is mixed into the second resin 41. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light-emitting device used for a liquid crystal backlight light source, a lighting fixture, a backlight light source for a display, a flashlight for a camera, a moving image illumination auxiliary light source, and the like.

  A light-emitting device using a light-emitting element emits light with a small color, high power efficiency, and vivid colors. In addition, since the light emitting element is a semiconductor element, there is no fear of a broken ball. Furthermore, the light-emitting element is characterized by excellent initial drive characteristics and resistance to vibration and repeated on / off lighting. Because of such excellent characteristics, light-emitting devices using light-emitting elements such as light-emitting diodes (hereinafter referred to as “LEDs”) and laser diodes (hereinafter referred to as “LDs”) are used as various light sources. .

  Conventionally, the following combinations are known for white light emitting devices using LEDs.

  First, there is a light-emitting device that combines a blue LED and a so-called YAG phosphor that emits yellow light. This light-emitting device excites a YAG phosphor with the light of a blue LED and emits white light with mixed color light of blue light and yellow light. This light-emitting device is widely used because it can reduce power consumption, easily perform LED drive control, and has good color mixing. However, this light-emitting device has poor color rendering properties. Further, since the phosphor particle size is about 5 μm to 15 μm, which is larger than the wavelength of visible light (380 nm to 780 nm), the fluorescence is backscattered by the front particles, and the light extraction efficiency is lowered.

  There is also a light emitting device that combines a blue LED and an organic dye. Since this light emitting device uses an organic dye unlike an inorganic phosphor, the light emitted from the blue LED does not scatter and has high utilization efficiency. However, organic dyes tend to degrade to blue light or external light of LEDs, and have a short life.

  Furthermore, there is a light-emitting device that combines a light-emitting element and a nanocrystal phosphor having an average particle diameter of 0.1 nm to 100 nm (see, for example, Patent Document 1). However, this light emitting device tends to cause color unevenness. Since the light emitting element has a light emission intensity difference between light emitted from the upper surface and light emitted from the side surface, the light emitted from the light emitting device may have different emission colors depending on the viewing direction.

JP 2004-071908 A

  In view of the above, an object of the present invention is to provide a light emitting device with extremely little color unevenness. Another object of the present invention is to provide a light-emitting device with high brightness.

  In order to solve the above-mentioned problems, the present inventors have intensively studied and as a result, the present invention has been completed.

  The present invention includes a light source, a pedestal on which the light source is disposed, a first wavelength conversion member that covers at least a part of the light source, and a first that covers at least a part of the first wavelength conversion member. 2, wherein the first wavelength conversion member absorbs at least part of light from the light source and emits light having a wavelength different from that of the light source. The diameter is 1 μm to 200 μm, and the second wavelength conversion member absorbs at least a part of light from the light source and light from the first wavelength conversion member and emits light having a wavelength different from that of the light source. The present invention relates to a light emitting device having an average particle diameter of 0.1 nm to 100 nm. Thus, a light emitting device with extremely little color unevenness can be provided.

  The first wavelength conversion member has a light emission peak wavelength on the longer wavelength side than the light emission peak wavelength of the light source, and the second wavelength conversion member emits light on a longer wavelength side than the light emission peak wavelength of the light source. It preferably has a peak wavelength. Since the wavelength conversion efficiency is high, a light-emitting device with high luminance can be provided.

  The emission peak wavelength of the first wavelength conversion member is preferably longer than the emission peak wavelength of the second wavelength conversion member. Since the light emitted from the first wavelength conversion member is emitted to the outside without being absorbed by the second wavelength conversion member, there is little loss of light. Thus, a light-emitting device with high luminance can be provided.

  The emission peak wavelength of the first wavelength conversion member is preferably in the range of 550 nm to 780 nm. By increasing the yellow to red component, a light emitting device having high color rendering properties can be provided.

  The emission peak wavelength of the second wavelength conversion member is preferably in the range of 470 nm to 550 nm. By increasing the components of blue-green to yellow-green, a light emitting device having high color rendering properties can be provided. In addition, since the conventional phosphor that emits green light easily deteriorates due to heat, a long-life light-emitting device can be provided by adopting this structure.

  The emission peak wavelength of the light source is preferably in the range of 360 nm to 470 nm. This is because the first wavelength conversion member and the second wavelength conversion member can be excited efficiently. This is to prevent ultraviolet rays of 350 nm or less from being emitted from the light emitting device.

  The light source is preferably a light emitting element. This is because it is small and highly efficient.

  The present invention is a light emitting device having a light source, a pedestal on which the light source is disposed, and a covering member that covers the light source, wherein the covering member has a first particle diameter of 1 μm to 200 μm. The present invention relates to a light emitting device having a wavelength conversion member and a second wavelength conversion member having an average particle diameter of 0.1 nm to 100 nm. Thus, a light emitting device that exhibits a desired emission color can be provided. In particular, since the second wavelength conversion member has an average particle diameter of nano units, the light from the light source and the light from the first wavelength conversion member are not blocked by the second wavelength conversion member and are emitted to the outside. Therefore, the emission luminance can be increased.

  The first wavelength conversion member may absorb at least a part of light from the light source and light from the second wavelength conversion member and emit light having a wavelength different from that of the light source. As a result, a light-emitting device that emits light different from the light source can be provided.

  The second wavelength conversion member may absorb at least part of light from the light source and light from the first wavelength conversion member and emit light having a wavelength different from that of the light source. As a result, a light-emitting device that exhibits an emission color different from that of the light source can be provided.

  The first wavelength conversion member and the second wavelength conversion member are preferably at least 15% by weight or more. This is because a predetermined amount or more is required to change the color tone.

  The present invention is configured as described above. For example, it is possible to provide a light emitting device with extremely little color unevenness. In addition, a high-luminance light-emitting device can be provided.

  Hereinafter, a light-emitting device and a manufacturing method thereof according to the present invention will be described with reference to embodiments and examples. However, the present invention is not limited to this embodiment and example. For the sake of convenience, the drawings may have portions exaggerated to describe the invention.

<First Embodiment>
The light emitting device according to the first embodiment will be described. FIG. 1 is a schematic cross-sectional view of the light emitting device according to the first embodiment.

  The light emitting device 100 includes a light emitting element 10 (light source), a first lead 20 (pedestal) on which the light emitting element 10 is disposed, a second lead 21 electrically connected to the light emitting element 10, and a first lead A phosphor 30 (first wavelength conversion member) disposed in the cup of the lead 10 and covering the light emitting element 10 and a nanophosphor 40 (second wavelength conversion member) covering the phosphor 30 are included. The phosphor 30 is mixed in the first resin 31. The nanophosphor 40 is mixed in the second resin 41. A portion including the cup of the first lead 20 where the light emitting element 10 is disposed and a part of the second lead 21 are fixed by the second resin 41.

  The light emitting element 10 has a pair of positive and negative electrodes on the same surface side. The pair of electrodes and the first lead 20 and the second lead 21 are electrically connected to each other through wires. The light emitting element 10 is fixed in the cup of the first lead 20 using a die bond member. The light emitting element 10 can be used not only having positive and negative electrodes on the same surface side but also having electrodes on the front and back surfaces. In this case, the back side electrode and the first lead 20 are electrically connected using a conductive member such as solder, and the front side electrode and the second lead 21 are electrically connected via a wire. Yes.

  The first lead 20 is provided with a cup for arranging the light emitting element 10. In addition to disposing the light emitting element 10 in the cup, the cup is filled with a first resin 31 mixed with a phosphor 30 that covers the light emitting element 10. The cup can also be formed in a mortar shape in order to efficiently emit light from the light emitting element 10 in the opening direction. Moreover, in order to reflect the light from the light emitting element 10 efficiently, a member with a high reflectance can be used for a cup, or a member with a high reflectance can also be arrange | positioned inside a cup.

  The phosphor 30 mixed in the first resin 31 may be uniformly dispersed in the cup, but is preferably settled in the vicinity of the light emitting element 10. This is because the color unevenness is further reduced by arranging the phosphor 30 in the vicinity of the light emitting element 10.

  It is preferable that the nanophosphor 40 mixed in the second resin 41 is uniformly dispersed. This is because uneven color is reduced. The first resin 31 is protected by the second resin 41 so that moisture permeation or adhesion of dust or the like does not occur. Therefore, the second resin 41 is preferably harder than the first resin 31. Further, since the nanophosphor 40 is separated from the light emitting element 10 which serves as a light source and a heat source, it is unlikely to be deteriorated by heat.

  The phosphor 30 absorbs part of the light from the light emitting element 10 to perform wavelength conversion, and emits light having a wavelength different from that of the light emitting element 10. The phosphor 30 is preferably excited by light from the light emitting element 10 and has the emission peak wavelength of the phosphor 30 on the longer wavelength side than the emission peak wavelength of the light emitting element 10. This is because the wavelength conversion efficiency is good. The nanophosphor 40 absorbs a part of the light from the light emitting element 10 to perform wavelength conversion, and emits light having a wavelength different from that of the light emitting element 10. The nanophosphor 40 is also excited by light from the light emitting element 10 and preferably has the emission peak wavelength of the nanophosphor 40 on the longer wavelength side than the emission peak wavelength of the light emitting element 10. In particular, the emission peak wavelength of the phosphor 30 is preferably longer than the emission peak wavelength of the nanophosphor 40. This is because the light emitted from the phosphor 30 is not absorbed by the nanophosphor 40 and is emitted to the outside.

  The average particle diameter of the phosphor 30 (first wavelength conversion member) is 1 μm to 200 μm. More preferably, it is 2 μm to 15 μm. Even when the phosphor 30 is efficiently excited, it has a slightly reflecting portion. Since the phosphor 30 has a predetermined size, the reflecting portion has a function of diffusing light.

  The average particle diameter of the nanophosphor 40 (second wavelength conversion member) is 0.1 nm to 100 nm. Since the nanophosphor 40 has a very small diameter, light diffusion hardly occurs. Therefore, even when light that is not absorbed by the nanophosphor 40 is incident, the nanophosphor 40 is hardly blocked and most of the light passes through the layer including the nanophosphor 40. Therefore, the light emission efficiency can be increased by eliminating the light blocking material. Moreover, the use of the nanophosphor 40 and the temperature quenching associated with the temperature rise as in the phosphor can be reduced, and the luminous efficiency can be increased.

  A part of the light emitted from the light emitting element 10 is applied to the phosphor 30. A part of the light irradiated to the phosphor 30 is wavelength-converted to emit predetermined light, but the light that is not absorbed by the phosphor 30 is reflected. In addition, since the particles of the phosphor 30 have a predetermined size, the light emitted from the light emitting element 10 is irradiated onto the phosphor 30 and light dispersion occurs. Thereby, when the light emitted from the light emitting element 10 passes through the first resin 31 including the phosphor 30, the light becomes relatively uniform, and the nanophosphor 40 included in the second resin 41 is converted into light. Irradiated. The light transmitted through the first resin 31 and absorbed by the nanophosphor 40 is wavelength-converted and emitted to the outside. However, even light that has passed through the first resin 31 does not absorb light having a wavelength longer than the emission peak wavelength of the nanophosphor 40, but even light that has not been absorbed by the nanophosphor 40, Light is irradiated outside without being dispersed. Since the particle size of the nanophosphor 40 is smaller than the wavelength of light (380 nm to 780 nm), the light irradiated to the second resin 41 is not blocked by the nanophosphor 40 and is emitted to the outside. Therefore, the luminous efficiency of the entire light emitting device 100 can be increased. The light that has passed through the first resin 31 and has not been irradiated onto the nanophosphor 40 is transmitted.

  In particular, it is preferable to use the light-emitting element 10 having an emission peak wavelength in the range of 360 nm to 470 nm. This is because energy is high. Moreover, it is preferable to use the nanophosphor 40 having an emission peak wavelength in the range of 470 nm to 550 nm, and it is preferable to use the phosphor 30 having an emission peak wavelength in the range of 550 nm to 780 nm. By combining these, uniform white light can be obtained. This is because light dispersion as described above occurs.

  Further details will be described.

(light source)
A light emitting element such as a light emitting diode (LED) or a laser diode (LD) can be used as the light source. In addition, a light source such as a filament or a lamp can be used. In this specification, description is made using a light-emitting element that is small and has high emission luminance.

(Light emitting element)
The light emitting element 10 is formed by forming a semiconductor such as GaAlN, ZnS, ZnSe, SiC, GaP, GaAlAs, AlN, InN, AlInGaP, InGaN, GaN, or AlInGaN on the substrate as a light emitting layer. Examples of the semiconductor structure include a homo structure having a MIS junction, a PIN junction, and a PN junction, a hetero structure, and a double hetero structure. Various emission wavelengths can be selected from ultraviolet light to infrared light depending on the material of the semiconductor layer and the degree of mixed crystal. The light emitting layer may have a single quantum well structure or a multiple quantum well structure which is a thin film in which a quantum effect is generated.

  The light emitting element 10 is not limited to one, and a plurality of light emitting elements 10 can be used. By combining a plurality of light emitting elements 10, the color mixing property in white display can be improved.

  The light-emitting element 10 is appropriately changed according to the absorption spectrum, emission spectrum, emission color of the light-emitting device 100, and the like of the phosphor 30 and the nanophosphor 40. This is because the first resin 31 that holds the phosphor 30 deteriorates when the emission peak wavelength is 300 nm or less.

(Phosphor)
The phosphor 30 (first wavelength conversion member) may be any member that absorbs light from the light emitting element 10 and converts the light into light having a different wavelength. For example, it is mainly activated by nitride-based phosphors / oxynitride-based phosphors mainly activated by lanthanoid elements such as Eu and Ce, lanthanoid-based phosphors such as Eu, and transition metal elements such as Mn. Alkaline earth halogen apatite phosphor, alkaline earth metal borate phosphor, alkaline earth metal aluminate phosphor, alkaline earth silicate, alkaline earth sulfide, alkaline earth thiogallate, alkaline earth nitriding Selected from silicon, germanate, or rare earth aluminate mainly activated by lanthanoid elements such as Ce, organic and organic complexes mainly activated by lanthanoid elements such as rare earth silicate or Eu It is preferable that it is at least any one or more. As specific examples, the following phosphors can be used, but are not limited thereto.

A nitride phosphor mainly activated by a lanthanoid element such as Eu or Ce is M ₂ Si ₅ N ₈ : Eu (M is at least one selected from Sr, Ca, Ba, Mg, Zn). There is.) In addition to M ₂ Si ₅ N ₈ : Eu, MSi ₇ N ₁₀ : Eu, M _1.8 Si ₅ O _0.2 N ₈ : Eu, M _0.9 Si ₇ O _0.1 N ₁₀ : Eu (M Is at least one selected from Sr, Ca, Ba, Mg, and Zn.

An oxynitride phosphor mainly activated by a lanthanoid element such as Eu or Ce is MSi ₂ O ₂ N ₂ : Eu (M is at least one selected from Sr, Ca, Ba, Mg, Zn) Etc.).

Alkaline earth halogen apatite phosphors mainly activated by lanthanoid compounds such as Eu and transition metal elements such as Mn include M ₅ (PO ₄ ) ₃ X: R (M is Sr, Ca, Ba). X is at least one selected from F, Cl, Br and I. R is any one of Eu, Mn, Eu and Mn. Etc.).

The alkaline earth metal borate phosphor has M ₂ B ₅ O ₉ X: R (M is at least one selected from Sr, Ca, Ba, Mg, Zn. X is F, Cl , Br, or I. R is Eu, Mn, or any one of Eu and Mn.).

Alkaline earth metal aluminate phosphors include SrAl ₂ O ₄ : R, Sr ₄ Al ₁₄ O ₂₅ : R, CaAl ₂ O ₄ : R, BaMg ₂ Al ₁₆ O ₂₇ : R, BaMg ₂ Al ₁₆ O ₁₂ : R, BaMgAl ₁₀ O ₁₇ : R (R is Eu, Mn, or any one of Eu and Mn).

Examples of the alkaline earth sulfide phosphor include La ₂ O ₂ S: Eu, Y ₂ O ₂ S: Eu, and Gd ₂ O ₂ S: Eu.

Examples of rare earth aluminate phosphors mainly activated with lanthanoid elements such as Ce include Y ₃ Al ₅ O ₁₂ : Ce, (Y _0.8 Gd _0.2 ) ₃ Al ₅ O ₁₂ : Ce, Y _{3 (Al 0.8 Ga 0.2) 5 O} 12: Ce, and the like (Y, Gd) 3 (Al , Ga) YAG -based phosphor represented by the compositional formula of _{5 O 12.} Further, there are Tb ₃ Al ₅ O ₁₂ : Ce, Lu ₃ Al ₅ O ₁₂ : Ce, etc. in which a part or all of Y is substituted with Tb, Lu or the like.

Other phosphors include ZnS: Eu, Zn ₂ GeO ₄ : Mn, MGa ₂ S ₄ : Eu (M is at least one selected from Sr, Ca, Ba, Mg, Zn. X is At least one selected from F, Cl, Br, and I).

  The phosphor described above contains at least one selected from Tb, Cu, Ag, Au, Cr, Nd, Dy, Co, Ni, and Ti instead of Eu or in addition to Eu as desired. You can also.

  Moreover, it is fluorescent substance other than the said fluorescent substance, Comprising: The fluorescent substance which has the same performance and effect can also be used.

  These phosphors can use phosphors having emission spectra in yellow, red, green, and blue by the excitation light of the light emitting element 10, and emit light in yellow, blue-green, orange, etc., which are intermediate colors thereof. A phosphor having a spectrum can also be used. By using these phosphors in various combinations, light emitting devices having various emission colors can be manufactured.

  As the phosphor 30, it is preferable to use a phosphor having an emission peak wavelength in the range of 550 nm to 780 nm.

(Nanophosphor)
As the nanophosphor 40 (second wavelength converting member), for example, BaMgAl ₁₀ O ₁₇ : Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, M ₅ (PO ₄ ) ₃ Cl: Eu (where M is Sr, Ca , Ba, Mg), M ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu (where M is at least one element selected from Sr, Ca, Ba, Mg) _{element), Sr 4 Al 14 O 25} : Eu, (Sr, Ba) Al 2 Si 2 O 8: Eu, 2SrO · xP 2 O 5 · yB 2 O 3: Eu ( provided that, x + y = 1), ZnS: Ag ZnS: Ag, Al, ZnS: Ag, Cl, (ZnCd) S: Ag, (ZnCd) S: Ag, Al, (ZnCd) S: Ag, Cl, and the like.

_{Further, Sr 2 Si 3 O 8 ·} 2SrCl 2: Eu, Ba 3 MgSi 2 O 8: Eu, SrGa 2 S 4: Eu, Y 2 SiO 5: Ce, Tb, LaPO 4: Ce, Tb, MgAl 11 O 19 : Ce, Tb, GdMgB ₅ O ₁₀ : Ce, Tb, Zn ₂ SiO ₄ : Mn, Re ₃ M ₅ O ₁₂ : Ce (where Re is selected from Y, Lu, Se, La, Gd, Sm) And at least one element selected from Al, Ga and In), ZnS: Cu, ZnS: Cu, Cl, ZnS: Cu, Al, ZnS: Cu, Ag, ZnS. : Cu, Au, Al, (ZnCd) S: Cu, (ZnCd) S: Cu, Cl, (ZnCd) S: Cu, Al, (ZnCd) S: Cu, Ag, (ZnCd) S: Cu, Au, A And the like.

Further, Y ₂ O ₃ : Eu, Y ₂ O ₂ S: Eu, Y ₂ O ₂ S: Eu, Bi, YVO ₄ : Eu, YVO ₄ : Eu, Bi, Y (PV) O ₄ : Eu, Y ( PV) O ₄ : Eu, Bi, CaS: Eu, SrS: Eu, (CaSr) S: Eu, 3.5MgO.0.5MgF ₂ .GeO ₂ : Mn, Re ₃ M ₅ O ₁₂ : Ce, Pr , Re is at least one element selected from Y, Lu, Se, La, Gd, and Sm, and M is at least one element selected from Al, Ga, and In).

  Moreover, CdTe, CdSe, ZnTe, ZnSe, CdS, ZnS, etc. are mentioned.

  It is preferable to use the nanophosphor 40 having an emission peak wavelength in the range of 470 nm to 550 nm.

<Method for manufacturing light emitting device>
A pair of first leads 20 and second leads 21 are used. The first lead 20 is provided with a cup for arranging the light emitting element 10. Since the first lead 20 and the second lead 21 are connected to an external current supply source, a conductive member is used.

  The light emitting element 10 is disposed in the cup of the first lead 20 using a die bond member. In addition to a resin such as an epoxy resin, a metal such as solder can also be used for the die bond member. A pair of positive and negative electrodes of the light-emitting element 10 is electrically connected to the first lead 20 and the second lead 21 through wires. The light emitting element 10 may be one having a pair of positive and negative electrodes on the same surface side, or one having a pair of positive and negative electrodes on the front and back surfaces. In this case, in order to electrically connect the light emitting element 10 and the first lead 20, a conductive die bond member is used.

  Next, the first resin 31 mixed with the phosphor 30 is injected into the cup of the first lead 20 in which the light emitting element 10 is disposed and cured. The phosphor 30 is mixed in advance in the first resin 31 and uniformly dispersed. It is preferable to use the first resin 31 having good adhesion to the first lead 20. The phosphors 30 in the first resin 31 disposed in the cup can be in a uniformly dispersed state or in a settled state. The light from the light emitting element 10 can be made uniform by setting the phosphor 30 in a settled state.

  Next, the liquid second resin 41 is poured into a mold that is recessed in a bowl shape. In the second resin 41, the nanophosphor 40 is mixed. The first lead 20 and the second lead 21 described above are inserted into the second resin 41 injected into the mold. The second resin 41 is submerged to the extent that the cup portion of the first lead 20 is immersed. Thereafter, the second resin 41 is cured to fix the first lead 20 and the second lead 21.

  Thereby, the light emitting device 100 can be manufactured.

<Second Embodiment>
The light emitting device 200 according to the second embodiment will be described. FIG. 2 is a schematic cross-sectional view of the light emitting device according to the second embodiment. However, description of parts using substantially the same members as those of the light emitting device 100 according to the first embodiment will be omitted.

  The light emitting device 200 includes a package 120 (pedestal) having a recess having a bottom surface and side surfaces, a light emitting element 110 (light source) disposed on the bottom surface of the recess of the package 120, and a first resin 131 that covers the light emitting element 110. And a second resin 141 provided on an upper portion of the recess of the package 120 and covering the first resin. In the first resin 131, a phosphor 130 (first wavelength conversion member) is mixed. Further, the nanophosphor 140 (second wavelength conversion member) is mixed in the second resin 141.

  The light-emitting element 110 can be formed using a gallium nitride compound semiconductor or the like. The light-emitting element 110 can have a pair of positive and negative electrodes on the same surface side, or can have a pair of positive and negative electrodes on the front and back surfaces.

  Package 120 has a recess having a bottom surface and side surfaces. The concave portion is formed to have a wide mouth from the bottom side toward the opening direction. The recess is formed in multiple stages. A metal lead is provided in the recess. The leads are continuously connected from the inside of the recess of the package 120 to the outside of the package 120 and have a role of supplying electricity to the light emitting element 110. The concave portion of the package 120 is preferably substantially circular as viewed from the opening direction. The concave portion of the package 120 has two stages. Leads are arranged in the first stage close to the bottom side. The first resin 131 is disposed up to the second stage close to the opening direction. A second resin 141 having a convex lens shape is assembled and fixed above the concave portion of the package 120. The outer shape of the package 120 is substantially a cube, but may be a substantially rectangular parallelepiped. Further, leads are arranged on the outer peripheral portion of the package 120. The package 120 may be made of ceramics in addition to a resin system such as a polyamide resin or a liquid crystal polymer.

  The phosphor 130 is mixed in the first resin 131. The lead 21 in the recess of the package 120 and the electrode of the light emitting element 110 are electrically connected via a wire. This wire is preferably disposed in the first resin 131.

  As the second resin 141, a lens formed in advance is used. Molded with acrylic resin. Further, as the second resin 141, glass or the like can be used instead of the resin. The second resin 141 formed in a predetermined shape is fitted into the recess of the package 120 and fixed. The nanophosphor 40 is mixed in the second resin 141. Since the nanophosphor 40 has a very small diameter of 0.1 nm to 100 nm, it does not easily precipitate and is dispersed almost uniformly in the second resin 141.

  A gas layer is provided between the second resin 141 and the first resin 131. As a result, even if the first resin 131 is thermally expanded by supplying a current to the light emitting element 110, the gas layer is interposed, so that the second resin 141 is not pushed up. In addition, it can replace with a gas layer and can also arrange | position resin. For example, by using the first resin 131, the resin replaced with the gas layer, and the second resin 141 in this order, the light extraction from the light emitting element 110 and the like can be improved.

  Thus, the light emitting device 200 can be provided.

<Third Embodiment>
A light emitting device according to a third embodiment will be described. FIG. 3 is a schematic cross-sectional view of the light emitting device according to the third embodiment.

  The light emitting device 300 includes a light emitting element 210 (light source), a package 220 (pedestal) in which the light emitting element 210 is disposed, and a covering member 250 that covers the light emitting element 210. The covering member 250 includes a phosphor 230 (first wavelength conversion member) having an average particle diameter of 1 μm to 200 μm and a nanophosphor 240 (second wavelength conversion member) having an average particle diameter of 0.1 nm to 100 nm. And having. The package 220 has a pair of positive and negative lead electrodes, and the light emitting element 210 is electrically connected to the lead electrodes. The covering member 250 is not particularly limited, but resin, glass, or the like can be used.

  Various relationships among the absorption wavelength, emission wavelength, and emission peak wavelength of the light emitting element 210, the phosphor 230, and the nanophosphor 240 are conceivable.

  A phosphor that has a light emission peak wavelength on the short wavelength side of visible light, absorbs light from the light emitting element 210, performs wavelength conversion, and has a light emission peak wavelength on a longer wavelength side than the light emitting element 210 230 and the nanophosphor 240 that absorbs light from the light emitting element 210 to perform wavelength conversion and has a light emission peak wavelength on the longer wavelength side than the light emitting element 210 can be used. For example, by using the light emitting element 210 that emits blue light, the phosphor 230 that emits red light, and the nanophosphor 240 that emits yellow light, it is possible to provide the light emitting device 300 with high color rendering. The phosphor 230 mainly absorbs light from the light-emitting element 210, but one that absorbs light from the nanophosphor 240 can also be used. Similarly, although the nanophosphor 240 mainly absorbs light from the light emitting element 210, one that absorbs light from the phosphor 230 can also be used.

  Further, the light emitting element 210 having a light emission peak wavelength on the short wavelength side of visible light is subjected to wavelength conversion by absorbing light from the light emitting element 210, and has a light emission peak wavelength on the longer wavelength side than the light emitting element 210. It is also possible to use the phosphor 230 and the nanophosphor 240 that absorbs light from the phosphor 230 and performs wavelength conversion, and has an emission peak wavelength on the longer wavelength side than the phosphor 230. For example, a light-emitting device 300 having high color rendering properties can be obtained by using a light-emitting element 210 that emits blue light, a phosphor 230 that emits green light, and a nano-phosphor 240 that absorbs green light and emits yellow-red light. Can be provided. Note that the nanophosphor 240 also mainly absorbs light from the phosphor 230, but one that absorbs light from the light emitting element 210 can also be used.

  Further, the light emitting element 210 having a light emission peak wavelength on the short wavelength side of visible light is subjected to wavelength conversion by absorbing light from the light emitting element 210, and has a light emission peak wavelength on the longer wavelength side than the light emitting element 210. It is also possible to use the nanophosphor 240 and the phosphor 230 that absorbs light from the nanophosphor 240 and performs wavelength conversion and has an emission peak wavelength on the longer wavelength side than the nanophosphor 240. For example, a light emitting device 300 having high color rendering is provided by using a light emitting element 210 that emits blue light, a nanophosphor 240 that emits green light, and a phosphor 230 that absorbs green light and emits red light. can do. The phosphor 230 mainly absorbs light from the nanophosphor 240, but one that absorbs light from the light emitting element 210 can also be used.

  Furthermore, instead of the light emitting element 210 whose emission peak wavelength is on the short wavelength side of visible light, the light emitting element 210 whose emission peak wavelength is near ultraviolet can be used. In this case, since the light from the light emitting element 210 is difficult to see, the light from the phosphor 230 and the nanophosphor 240 is mainly viewed. For example, a light emitting element 210 having an emission peak wavelength in the near ultraviolet, a phosphor 230 that emits blue light, and a nanophosphor 240 that absorbs blue and emits yellow light can also be used.

  In any of the light emitting devices, since the nanophosphor 240 does not block the light from the light emitting element 210 or the light from the phosphor 230, the light emission luminance can be increased.

  Note that the emission peak wavelength of short wavelength side of visible light means 380 nm or more and 495 nm or less, and the emission peak wavelength of near ultraviolet means that of 300 nm or more and less than 380 nm.

  The phosphor 230 and the nanophosphor 240 are preferably at least 15% by weight or more, and more preferably 30% by weight or more.

  Although the dispersion state of the phosphor 230 and the nanophosphor 240 contained in the covering member 250 cannot be clearly stated, the aggregation of the phosphor 230 is suppressed by mixing the phosphor 230 and the nanophosphor 240. Can do. This is presumably because the nanophosphor 240 adheres to the outer periphery of the phosphor 230 and suppresses aggregation of the phosphor 230.

  The phosphor 230 and the nanophosphor 240 in the covering member 250 may be roughly divided into two layers. By using the phosphor 230 and the nanophosphor 240 having different specific gravities, a substance having a large specific gravity can be produced by sedimenting downward. By using the covering member 250 having the phosphor 230 on the lower side and the nanophosphor 240 on the upper side, light from the phosphor 230 can be emitted to the outside without being blocked by the upper nanophosphor 240. . By using the phosphor 230 having the emission peak wavelength on the longer wavelength side than the nanophosphor 240, the light emitted from the phosphor 230 can be emitted to the outside without being absorbed by the nanophosphor 240. A high-luminance light-emitting device can be provided.

<Example 1>
The light emitting device 100 according to Example 1 will be described. FIG. 1 is a schematic cross-sectional view of a light emitting device. In addition, since it has the structure substantially the same as the light-emitting device 100 which concerns on 1st Embodiment, there is also a part which abbreviate | omits description.

The light emitting element 10 uses a gallium nitride compound semiconductor having an emission peak wavelength at about 460 nm. The light emitting element 10 is disposed in the cup of the first lead 20. An epoxy resin is used as a die bonding member for fixing the light emitting element 10. The first lead 20 and the second lead 21 are used. A pair of positive and negative electrodes of the light emitting element 10 is electrically connected to the first lead 20 and the second lead 21 via Au wires. The first resin 31 is dropped and filled into the cup of the first lead 20. The phosphor 30 is mixed in the first resin 31. The phosphor 30 uses CaAlSiN ₃ : Eu having an emission peak wavelength of 630 nm to 670 nm and an average particle diameter of 5 μm. The second resin 41 is disposed so as to cover the first resin 31 and the cup of the first lead 20 and a part of the second lead 21. In the second resin 41, a nanophosphor 40 is mixed. The nanophosphor 40 uses ZnS: Cu having an emission peak wavelength at 470 nm to 550 nm. The phosphor 30 is excited by light from the light emitting element 10 and emits red light. A part of the light from the light emitting element 10 is reflected even if it is irradiated to the phosphor 30. The light irradiated and reflected on the phosphor 30 is dispersed and irradiated onto the nanophosphor 40. The light from the light emitting element 10 that has passed through the first resin 31 is also irradiated on the nanophosphor 40. As a result, the light applied to the nanophosphor 40 is wavelength-converted and emits green light. On the other hand, the light emitted from the phosphor 30 is not absorbed by the nanophosphor 40 and passes through the second resin 41. Accordingly, the light emitting device 100 that emits white light by mixing the blue light from the light emitting element 10, the red light from the phosphor 30, and the green light from the nanophosphor 40 can be provided. Thus, the light emitting device 100 with extremely little color unevenness can be provided. In addition, the light-emitting device 100 having high color rendering properties and high luminance can be provided.

<Example 2>
The light emitting device according to Example 2 is substantially the same as the light emitting device according to Example 1 except that the nanophosphor 40 is different.

A YAG (yttrium, aluminum, garnet) phosphor having an average particle diameter of 40 nm is used as the nanophosphor 40. The light emitting element 10 uses a gallium nitride compound semiconductor having an emission peak wavelength at about 460 nm. The phosphor 30 uses CaAlSiN ₃ : Eu having an emission peak wavelength of 630 nm to 670 nm and an average particle diameter of 5 μm. The phosphor 30 is excited by light from the light emitting element 10 and emits red light. A part of the light from the light emitting element 10 is reflected even if it is irradiated to the phosphor 30. The light irradiated and reflected on the phosphor 30 is dispersed and irradiated onto the nanophosphor 40. The light from the light emitting element 10 that has passed through the first resin 31 is also irradiated on the nanophosphor 40. As a result, the light irradiated on the nanophosphor 40 is converted in wavelength and emitted yellow. On the other hand, the light emitted from the phosphor 30 is not absorbed by the nanophosphor 40 and passes through the second resin 41. Thus, the light emitting device 100 that emits white light by mixing the blue light from the light emitting element 10, the red light from the phosphor 30, and the yellow light from the nanophosphor 40 can be provided. Thus, the light emitting device 100 with extremely little color unevenness can be provided. In addition, the light-emitting device 100 having high color rendering properties and high luminance can be provided.

  The light emitting device of the present invention can be used for a liquid crystal backlight light source, a lighting fixture, a display backlight light source, a camera flash light, a moving image illumination auxiliary light source, and the like.

It is a schematic sectional drawing of the light-emitting device which concerns on 1st Embodiment. It is a schematic sectional drawing of the light-emitting device which concerns on 2nd Embodiment. It is a schematic sectional drawing of the light-emitting device which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light emitting element 20 1st lead 21 2nd lead 30 Phosphor 31 First resin 40 Nano fluorescent substance 41 2nd resin 100 Light emitting device 110 Light emitting element 120 Package 130 Phosphor 131 First resin 140 Nano fluorescent substance 141 Second resin 200 Light emitting device

Claims (11)

A light source;
A pedestal on which the light source is disposed;
A first wavelength conversion member on which at least a part of the light source is coated;
A second wavelength conversion member that covers at least a portion of the first wavelength conversion member;
A light emitting device comprising:
The first wavelength conversion member absorbs at least a part of light from the light source and emits light having a wavelength different from that of the light source, and has an average particle diameter of 1 μm to 200 μm,
The second wavelength conversion member absorbs at least a part of light from the light source and light from the first wavelength conversion member and emits light having a wavelength different from that of the light source. A light emitting device having a thickness of 1 nm to 100 nm. The first wavelength conversion member has a light emission peak wavelength on the longer wavelength side than the light emission peak wavelength of the light source, and the second wavelength conversion member emits light on a longer wavelength side than the light emission peak wavelength of the light source. The light emitting device according to claim 1, wherein the light emitting device has a peak wavelength. 3. The light emitting device according to claim 1, wherein an emission peak wavelength of the first wavelength conversion member is longer than an emission peak wavelength of the second wavelength conversion member. 4. The light emitting device according to claim 1, wherein an emission peak wavelength of the first wavelength conversion member is in a range of 550 nm to 780 nm. 5. 5. The light emitting device according to claim 1, wherein an emission peak wavelength of the second wavelength conversion member is in a range of 470 nm to 550 nm. 6. The light emitting device according to claim 1, wherein an emission peak wavelength of the light source is in a range of 360 nm to 470 nm. The light-emitting device according to claim 1, wherein the light source is a light-emitting element. A light source;
A pedestal on which the light source is disposed;
A covering member that covers the light source;
A light emitting device comprising:
The covering member includes a first wavelength conversion member having an average particle diameter of 1 μm to 200 μm and a second wavelength conversion member having an average particle diameter of 0.1 nm to 100 nm. . The first wavelength conversion member absorbs at least part of light from the light source and light from the second wavelength conversion member and emits light having a wavelength different from that of the light source. 9. The light emitting device according to 8. The second wavelength conversion member absorbs at least a part of light from the light source and light from the first wavelength conversion member and emits light having a wavelength different from that of the light source. 9. The light emitting device according to 8. The light emitting device according to claim 8, wherein the first wavelength conversion member and the second wavelength conversion member are at least 15 wt% or more.

Images