JP2003101078A - Light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the light guide-out efficiency of a light-emitting device, which converts the wavelength of part of light from a light emitting element by a phosphor and emits light. SOLUTION: The phosphor 30 and a diffusing material 31, having a refractive index distribution, are incorporated in a transmissive resin layer 27 arranged where it is irradiated with the light from a light-emitting element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device. Specifically, it relates to a light emitting device in which a light emitting element and a phosphor are combined.

[0002]

2. Description of the Related Art A part of light emitted from a light-emitting element is wavelength-converted by a phosphor, and the wavelength-converted light and the light of the light-emitting element which is not wavelength-converted are mixed and emitted. A light emitting device that emits light of a different color has been developed. For example, a light emitting device using a group III nitride compound semiconductor light emitting element that emits blue light as a light emitting element and a yttrium-aluminum garnet-based phosphor (YAG) activated with cerium (Ce) as a phosphor. Is commercially available. In such a light emitting device, the light emitting element is mounted on the cup portion of the lead frame, and the light transmissive material in which the phosphor (YAG) is dispersed is filled in the cup portion so as to cover the light emitting element. As a result, a phosphor layer is formed in the light emitting direction of the light emitting element. In such a configuration, when a part of the light of the light emitting element passes through the phosphor layer,
Emitted after being absorbed by the phosphor (YAG) and converted in wavelength,
Other light is emitted through the phosphor layer without being absorbed by the phosphor. Then, white light emission is obtained by mixing these two types of light.

[0003]

In the light emitting device using the light emitting element and the phosphor as described above, the lights of different wavelengths are mixed and emitted to the outside, so that the mixing of the lights is promoted and the unevenness of the emission color is reduced. Is required. Therefore, a configuration has been proposed in which a light-transmissive material that disperses the phosphor contains a diffusing material (titanium oxide or the like) (see, for example, JP-A-10-
173240, JP 2000-208815 A, etc.). By using the diffusing material, the light of the light emitting element or the light from the phosphor is diffused by the diffusing material, so that the two colors are mixed well. However, since the diffusion material such as titanium oxide that is conventionally used diffusely reflects the light irradiated on it, part of the light is reflected to the light emitting element side, that is, it becomes light that is opposite to the light extraction direction. The extraction efficiency (luminous efficiency) of is reduced.
The present invention has been made to solve the above problems,
An object of the present invention is to improve the light extraction efficiency, that is, the light emission efficiency, in a light emitting device that uses a phosphor to convert a part of light into a wavelength and emits the light.

[0004]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the inventors of the present invention have come up with the following constitution. That is, the present invention is a light emitting device including a light emitting element, a phosphor that receives the light of the light emitting element and fluoresces, and a light transmissive material layer that includes a diffusing material having a refractive index distribution.

Here, the diffusing material having a refractive index distribution contained in the light transmissive material layer reflects most of the light irradiating it toward the traveling direction. Therefore, in the above configuration,
It is possible to significantly suppress the generation of light that is backward in the light extraction direction due to the reflection by the diffusing material. That is, the light from the light emitting element or the light converted by the phosphor is
It is possible to efficiently proceed in the light extraction direction.
As a result, a light emitting device with high light extraction efficiency (light emission efficiency) is obtained.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A light emitting device has an emission wavelength of 36
Those in the range of 0 nm to 550 nm are preferably used. Light in such a wavelength range can excite the phosphor described below with high efficiency to cause it to emit light. In the selection of the light emitting element, the excitation peak and the emission color of the phosphor, which will be described later, and the color of the light emitted from the entire light emitting device are considered. In order to obtain white light emission, for example, a light emitting element that emits blue light (for example, an emission peak wavelength is 450 nm
It is possible to employ a light emitting device having a wavelength range of up to 500 nm. In this case, for example, a phosphor having a yellow or green fluorescent color is used as the fluorescent substance described below so that white fluorescent light can be obtained by mixing the fluorescent substance described later with blue light. You can As another example of obtaining white light emission, a light emitting element that emits light in the ultraviolet region (for example, a light emitting element having an emission peak wavelength in the range of 360 nm to 400 nm) is used, and each of them is red and green. An example is a mode in which a phosphor made of a fluorescent material that emits blue-based fluorescence is used in combination.

It is also possible to employ a light emitting element having an emission peak in two or more wavelength regions. For example, if a light emitting element that emits light in the visible region as well as light in the ultraviolet region is used,
The light in the ultraviolet region can be used for exciting the phosphor, while the light in the visible region can be used as a part of the light of the external emission light. With this configuration, the light emitting device emits the light, which is a mixture of the fluorescent light of the phosphor and the visible light emitted from the light emitting element, to the outside. For example, by adopting a light-emitting element capable of emitting ultraviolet light and blue light, and combining phosphors that emit green-based or red-based fluorescence with ultraviolet light, light-emitting devices of various emission colors are configured. be able to. Two or more light emitting elements having different emission wavelengths (emission colors) can be used in combination. In this way, the color of the light emitted from the light emitting device can be changed, adjusted, or corrected.

Materials for forming the light emitting element are not particularly limited
is not. Light emission comprising a group III nitride compound semiconductor layer
A device, that is, a group III nitride compound semiconductor light emitting device is preferable.
It can be used appropriately. Group III nitride compound semiconductor
Is the general formula Al_XGa _YIn_1-XYN (0 ≦
X ≦ 1, 0 ≦ Y ≦ 1, 0 ≦ X + Y ≦ 1), and Al
So-called binary system of N, GaN and InN, Al_xGa
_1-xN, Al_xIn_{1 -X}N and Ga_xIn_1-xN
Includes so-called ternary system (0 <x <1 in the above)
It Boron (B) and at least part of Group III elements
It may be replaced with um (Tl), etc.
At least part of it is phosphorus (P), arsenic (As), antimony
(Sb), bismuth (Bi) or the like. Luminescent element
The element function part of the child is the group III of the above binary system or ternary system.
It is preferably composed of a nitride compound semiconductor.

The group III nitride compound semiconductor may contain any dopant. As an n-type impurity,
Si, Ge, Se, Te, C or the like can be used.
As p-type impurities, Mg, Zn, Be, Ca, Sr, B
a or the like can be used. Note that the group III nitride compound semiconductor can be exposed to electron beam irradiation, plasma irradiation, or heating by a furnace after being doped with p-type impurities, but it is not essential. Group III nitride compound semiconductors are well known in the art, including metalorganic vapor phase epitaxy (MOCVD), well-known molecular beam crystal growth (MBE), and halide vapor phase (HV).
It can also be formed by a PE method), a sputtering method, an ion plating method, an electron shower method, or the like.

The material of the substrate on which the group III nitride compound semiconductor layer is grown is not particularly limited as long as it can grow the group III nitride compound semiconductor layer. For example, sapphire, spinel, silicon, silicon carbide, Examples of the substrate material include zinc oxide, gallium phosphide, gallium arsenide, magnesium oxide, manganese oxide, and group III nitride compound semiconductor single crystals. Above all,
It is preferable to use a sapphire substrate, and it is more preferable to use the a-plane of the sapphire substrate.

As the base material (light-transmitting material) of the light-transmitting material layer, epoxy resin, silicone resin, silicone rubber, silicone elastomer, urea resin, glass or the like can be used. These materials may be used alone, or two or more kinds of materials arbitrarily selected from them may be used. Above all, it is preferable to use an epoxy resin from the viewpoint of easy handling and versatility. When silicone resin, silicone rubber, or silicone elastomer is used,
The surface (externally exposed surface) is preferably coated with a material having high impact resistance. For example, the surface of the sealing member can be covered with a molded epoxy resin or the like. The light transmissive material layer is provided at a position irradiated with light from the light emitting element. Thereby, the phosphor contained therein is irradiated with light. Preferably, a light transmissive material layer is formed so as to cover the light emitting side of the light emitting element, and the phosphor is efficiently irradiated with light. The light-emitting element can be sealed with the light-transmitting material layer. Further, a layer or a space made of a material different from the light transmissive material layer may be provided between the light emitting element and the light transmissive material layer. For example, a silicone resin can be applied to the surface of the light emitting element, and a light transmissive material layer having an epoxy resin or the like as a base material can be formed thereon.

A phosphor is added to the light transmissive resin layer.
It The type of phosphor here is excited by the light of the light emitting element.
It is not particularly limited as long as it is fluorescent, and it is an inorganic type or an organic type.
It can be adopted regardless of system. As an inorganic phosphor
The following can be adopted. For example, red
-Based 6MgO · As with emission color_TwoO₅: Mn⁴⁺,
Y (PV) O_Four: Eu, CaLa_0.1Eu_0.9Ga
_ThreeO₇, BaY_0.9Sm_0.1Ga_ThreeO₇, Ca (Y
_0.5Eu_0.5) (Ga_0.5In_0.5)_ThreeO₇,
Y_ThreeO_Three: Eu, YVO_Four: Eu, Y_TwoO_Two: Eu,
3.5MgO ・ 0.5MgF_TwoGeO_Two: Mn ⁴⁺, And
(Y ・ Cd) BO_Two: Has a blue emission color such as Eu
(Ba, Ca, Mg)₅(PO_Four)_ThreeCl: E
u²⁺, (Ba, Mg)_TwoAl₁₆O₂₇: Eu²⁺,
Ba_ThreeMgSi_TwoO₈: Eu²⁺, BaMg_TwoAl₁₆
O₂₇: Eu^{Two +}, (Sr, Ca)₁₀(PO_Four)₆C
l_Two: Eu²⁺ , (Sr, Ca)₁₀(PO_Four)₆C
l_Two・ NB_TwoO_Three: Eu²⁺, Sr₁₀(PO_Four)₆C
l_Two: Eu²⁺, (Sr, Ba, Ca)₅(PO_Four)_Three
Cl: Eu²⁺, Sr_TwoP_TwoO₇: Eu, Sr₅(PO
_Four)_ThreeCl: Eu, (Sr, Ca, Ba)_Three(PO_Four)
₆Cl: Eu, SrO · P_TwoO₅・ B_TwoO₅: Eu,
(BaCa)₅(PO_Four)_ThreeCl: Eu, SrLa
_0.95Tm_0.05Ga_ThreeO₇, ZnS: Ag, Ga
WO_Four, Y_TwoSiO₆: Ce, ZnS: Ag, Ga, C
l, Ca_TwoB_FourOCl: Eu²⁺, BaMgAl
_FourO_Three: Eu²⁺, And the general formula (M1, Eu)₁₀(P
O _Four)₆Cl_Two(M1 is Mg, Ca, Sr, and Ba
At least one element selected from the group consisting of
Having a green-based emission color such as phosphors_ThreeAl ₅O
₁₂: Ce³⁺(YAG), Y_TwoSiO₅: Ce³⁺，
Tb³⁺, Sr_TwoSi_ThreeO₈・ 2SrCl_Two: Eu, B
aMg_TwoAl₁₆O₂₇: Eu²⁺, Mn^{Two +}, ZnS
iO_Four: Mn, Zn_TwoSiO_Four: Mn, LaPO_Four: T
b, SrAl _TwoO_Four: Eu, SrLa_0.2Tb_0.8
Ga_ThreeO₇, CaY_0.9Pr_0.1Ga_ThreeO₇, Zn
Gd_0.8Ho_0.2Ga_ThreeO₇, SrLa_0.6Tb
_0.4Al_ThreeO₇, ZnS: Cu, Al, (Zn, C
d) S: Cu, Al, ZnS: Cu, Au, Al, Zn
_TwoSiO_Four: Mn, ZnSiO_Four: Mn, ZnS: A
g, Cu, (Zn · Cd) S: Cu, ZnS: Cu, G
dOS: Tb, LaOS: Tb, YSiO_Four: Ce ・ T
b, ZnGeO_Four: Mn, GeMgAlO: Tb, Sr
GaS: Eu²⁺, ZnS: Cu / Co, MgO / nB
_TwoO_Three: Ge, Tb, LaOBr: Tb, Tm, and L
a_TwoO_TwoS: Tb or the like can be used. Also white
YVO with system emission color_Four: Dy, yellowish emission color
Have CaLu _0.5Dy_0.5Ga_ThreeO₇To use
I can do it.

The following can be adopted as the organic phosphor. For example, 1,4-bis (2-methylstyryl) benzene (Bis-MSB), trans-4,
Stilbene dyes such as 4'-diphenylstilbene (DPS), and coumarin dyes such as 7-hydroxy-4-methylcoumarin (coumarin 4), BOQP, PBBO,
BOT, POPOP, etc. can be used. These phosphors have a blue emission color. In addition, DPOT, brilliant sulfoflavin FF (brilliantsulfoflav
ine FF), basic yellow HG (basic yellow H)
G), SINLOIHI COLOR FZ-5005 (manufactured by Shinroyhi Co., Ltd.) and the like can also be used. These phosphors have a yellow to green fluorescent color. In addition, yellow to red phosphors such as eosin and rhodamine 6G (rhodamin)
e 6G), Rhodamine B (rhodamineB), NKP-8303 (manufactured by Nippon Fluorescent Chemical Co., Ltd.) and the like can also be used. Also, TB
It is also possible to use (EDTA) SSA, EuTTA, etc. dissolved in, for example, methyl methacrylate and polymerized and solidified to form polymethyl methacrylate (PMMA).
It should be noted that it is also possible to use two or more different types of phosphors in combination.

The concentration distribution of the phosphor in the light transmissive material layer can be changed according to the purpose of use, the conditions of use and the like. That is, the amount of the phosphor can be changed continuously or stepwise as it approaches the light emitting element. For example,
The concentration of the phosphor is increased in the portion close to the light emitting element. Thereby, the phosphor can be efficiently irradiated with the light from the light emitting element. On the other hand, it is easily affected by heat generated in the light emitting element, which causes deterioration of the phosphor. On the other hand, by decreasing the concentration of the phosphor as it approaches the light emitting element, deterioration of the phosphor due to heat generation of the light emitting element is suppressed. For example, by coating the surface (light emitting side) of the light emitting element with a small amount of a light-transmitting material in which a phosphor is dispersed, and stacking a light-transmitting material that does not contain a phosphor thereon, a phosphor resin layer It is possible to change the concentration distribution of the amount of the fluorescent substance inside. Here, a plurality of sealing members having different phosphor addition amounts may be prepared, and these may be laminated in order to gradually change the phosphor addition amount as the distance from the light emitting element side increases. It is also possible to prepare a plurality of light transmissive materials to which phosphors of different types are added and to stack these in order.

The light transmissive material layer contains a diffusing material having a refractive index distribution in addition to the phosphor. By using such a diffusing agent, diffusion of light in the light transmissive material layer is first promoted, and the light from the light emitting element can be efficiently applied to the phosphor. Further, the color mixture of the light from the light emitting element and the fluorescence of the phosphor can be promoted, and the color mixture unevenness and the light emission unevenness can be reduced. Moreover, by adopting the diffusing material having the refractive index distribution, the reflection of light in the direction opposite to the light extraction direction is suppressed, and the light extraction efficiency (light emission efficiency) is increased.

Here, "having a refractive index distribution" means that the refractive index is not uniform in the diffusing material. Therefore, there are positions where the refractive index is maximum and positions where the refractive index is minimum in the diffusing material. As the diffusing material having such a refractive index distribution, for example, the one disclosed in JP-A-6-347616 can be adopted. The publication discloses a transparent diffusing material obtained by radically copolymerizing two or more radically polymerizable monomers (styrene, styrene derivatives, methacrylic acid esters, acrylic acid esters, etc.) having different refractive indexes. The difference between the maximum and minimum values of the refractive index in the diffusing material is 0.005 or more, the difference between the refractive indices of two arbitrary points 50 nm apart is 0.01 or less, or the above-mentioned maximum and minimum values of the refractive index. Is less than 1/2 of the difference between the two, and the regions having different refractive indices are not unevenly distributed (diameter 5 mm at any position in the diffusing material)
The average of the refractive index in the circle is almost equal to the average of the refractive index of the entire diffusing material) is disclosed,
In the present invention, a diffusing material having such characteristics can be preferably adopted. The characteristics and manufacturing method of the above diffusing material are described in detail in this publication, so please refer to them. The diffusing material may be contained in the light transmissive material layer in a dispersed state, but may have a concentration distribution like the phosphor.

In addition to the above-mentioned phosphor and the diffusing material having the refractive index distribution, other light diffusing materials (for example, titanium oxide, titanium nitride, tantalum nitride, aluminum oxide, silicon oxide, etc.) can be used in the light transmitting material layer. It is also possible to add a barium titanate or the like) or a coloring agent. The colorant is used exclusively to prevent the phosphor itself from exhibiting a unique color.

[0018]

EXAMPLES The constitution of the present invention will be described in more detail with reference to examples. (Embodiment 1) FIG. 1 shows a cannonball type L which is an embodiment of the present invention.
It is a figure which shows ED1. LED1 emits white light,
For example, it can be used for a planar light source or a linear light source in combination with a light guide, and can also be used for various display devices. FIG. 2 shows a schematic cross-sectional view of the light emitting element 10 used for the LED 1. The emission wavelength of the light emitting element 10 is about 480 nm, and the specifications of each layer are as follows.

An n-type layer 13 made of GaN doped with Si as an n-type impurity is formed on the substrate 11 via a buffer layer 12. Here, although sapphire is used for the substrate 11, it is not limited to this, and sapphire,
Spinel, silicon, silicon carbide, zinc oxide, gallium phosphide, gallium arsenide, magnesium oxide, manganese oxide, Group III nitride compound semiconductor single crystal, or the like can be used. Further, the buffer layer is made of AlN and is MOC.
Although it is formed by the VD method, the material is not limited to this, and GaN, InN, AlGaN, InGaN, AlInGaN, or the like can be used as the material, and a molecular beam crystal growth method (MBE method) or a halide-based method A vapor phase growth method (HVPE method), a sputtering method, an ion plating method, an electron shower method or the like can be used. When the group III nitride compound semiconductor is used as the substrate, the buffer layer can be omitted. Further, the substrate and the buffer layer can be removed as needed after the semiconductor element is formed.

Although the n-type layer 13 is made of GaN,
AlGaN, InGaN or AlInGaN can be used. The n-type layer 13 is an n-type impurity and is S
i was doped, but in addition to this, G was added as an n-type impurity.
It is also possible to use e, Se, Te, C or the like. n-type layer 1
3 can have a two-layer structure composed of a low electron concentration n-layer on the layer 14 side including a light emitting layer and a high electron concentration n + layer on the buffer layer 12 side. The layer 14 including a layer that emits light may include a quantum well structure (multiple quantum well structure or single quantum well structure), and the structure of the light emitting element is a single hetero type, a double hetero type, and a homojunction. It may be a mold or the like. The layer 14 including the light emitting layer is a p-type layer 15
A group III nitride compound semiconductor layer having a wide bandgap doped with an acceptor such as magnesium may be included on the side of. This is to effectively prevent the electrons injected into the layer 14 including the light emitting layer from diffusing into the p-type layer 15. A p-type layer 15 made of GaN doped with Mg as a p-type impurity is formed on the layer 14 including a light emitting layer. This p-type layer is AlGaN, InGaN or In
AlGaN can also be used, and Zn, Be, Ca, Sr, and Ba can be used as the p-type impurities. Further, the p-type layer 15 may have a two-layer structure including a low hole concentration p− layer on the layer 14 side including a layer emitting light and a high hole concentration p + layer on the electrode side. In the light emitting diode having the above structure, each group III nitride compound semiconductor layer is formed by performing MOCVD under general conditions, or is formed by a molecular beam crystal growth method (MBE method) or a halide vapor phase growth method (H
VPE method), sputtering method, ion plating method, electron shower method, or the like.

The n-electrode 19 is composed of two layers of Al and V,
After the p-type layer 15 is formed, a part of the p-type layer 15, the layer 14 including a light emitting layer, and the n-type layer 13 is removed by etching, and the p-type layer 15 is formed on the n-type layer 13 by vapor deposition. The transparent electrode 17 is a thin film containing gold and is laminated on the p-type layer 15. The p-electrode 18 is also made of a material containing gold, and is formed on the translucent electrode 17 by vapor deposition. After each semiconductor layer and each electrode are formed by the above process, a separation process of each chip is performed.

A reflective layer may be provided between the layer 14 including a light emitting layer and the substrate 11 or on the surface of the substrate 11 on which the semiconductor layer is not formed. By providing the reflective layer, the light generated in the light emitting layer 14 and directed to the substrate side can be efficiently reflected in the light extraction direction, and as a result, the light emitting efficiency can be improved. The reflective layer can be formed of one kind or two or more kinds selected from titanium nitride, zirconium nitride, and tantalum nitride. Also, A
l, In, Cu, Ag, Pt, Ir, Pd, Rh, W,
The reflective layer can also be formed by using a single metal such as Mo, Ti, or Ni or an alloy composed of two or more kinds of metals arbitrarily selected from these.

The light emitting element 10 is mounted on the cup-shaped portion 25 provided on the lead frame 20 using an adhesive. The adhesive is a silver paste in which silver is mixed as a filler in an epoxy resin. The use of such a silver paste improves heat dissipation from the light emitting element 10.
Instead of the silver paste, other known adhesives such as transparent paste and white paste may be used. The p electrode 18 and the n electrode 19 of the light emitting element 10 are wire-bonded to the lead frames 21 and 20 by wires 41 and 40, respectively.

The cup-shaped portion 25 is filled with an epoxy resin (hereinafter referred to as “phosphor / diffusing material-containing layer”) 27 in which the fluorescent material 30 and the diffusing material 31 are uniformly dispersed. After the wire bonding described later, this phosphor / diffusing material-containing layer 27
It is also possible to fill the cup-shaped portion 25 with. In addition, a phosphor / diffusing material-containing layer may be formed on the surface of the light emitting element 10 before mounting the light emitting element 10 on the cup-shaped portion 25.
For example, by dipping the light emitting element 10 in an epoxy resin containing the phosphor 30 and the diffusing material 31, the light emitting element 1
A phosphor / diffusing material-containing layer is formed on the surface of No. 0, and then the light emitting element 10 is mounted on the cup-shaped portion 25 using silver paste. As a method for forming the phosphor / diffusing material-containing layer 27, sputtering, coating, painting, or the like can be used in addition to the above dipping.

The phosphor 30 is made of ZnS: Cu, Au, Al.
(Emission peak 535 nm) is used. The diffusing material 31 includes
A random copolymer of methyl methacrylate and vinylphenyl acrylate, in which particles whose refractive index continuously decreases from the central part to the peripheral part is used (for details of the manufacturing method, see JP-A-6-347616). I want to be). In addition, a random copolymer of methyl methacrylate and vinyl benzoate can be used.

In this embodiment, an epoxy resin is used as a base material in which the phosphor 30 and the diffusing material 31 are dispersed, but the base material is not limited to this, and a transparent material such as a silicone resin, a urea resin, or glass is used. You can Also,
Although the phosphor 30 and the diffusing material 31 are uniformly dispersed in the phosphor / diffusing material-containing layer 27 in the present embodiment, the phosphor 30 and / or the diffusing material 31 in the phosphor / diffusing material layer 27 is arranged.
It is also possible to provide a gradient in the concentration distribution of. For example, by stacking epoxy resins having different concentrations of the phosphor 30 and the diffusing material 31 in the cup-shaped portion 25, the phosphor 30 concentration and the diffusing material 31 concentration are changed stepwise in the cup-shaped portion 25. It is also possible to continuously change the concentration of the phosphor 30 and / or the concentration of the diffusing material 31.

The phosphor / diffusing material containing layer 27 may further contain a second diffusing material made of titanium oxide, titanium nitride, tantalum nitride, aluminum oxide, silicon oxide, barium titanate or the like.

Light emitting element 10, lead frames 20, 21
, And the wires 40 and 41 are sealed with a sealing resin 50 made of epoxy resin. The material of the sealing resin 50 is not particularly limited as long as it is transparent, but silicone resin, urea resin, or glass is preferably used in addition to epoxy resin. Further, from the viewpoint of the adhesiveness to the phosphor / diffusing material-containing layer 27, the refractive index, etc., it is preferably formed of the same material as the base material of the phosphor / diffusing material-containing layer 27.

The sealing resin 50 is provided for the purpose of protecting the element structure and the like, but a lens effect can be imparted to the sealing resin 50 by changing the shape of the sealing resin 50 according to the purpose. For example, in addition to the cannonball type shown in FIG. 1, it can be molded into a concave lens type or a convex lens type. Further, the shape of the sealing resin 50 when viewed from the light extraction direction (upper side in FIG. 1) can be circular, elliptical, or rectangular.

In the LED 1 configured as described above, a part of the blue light emitted from the light emitting element 10 irradiates the phosphor 30 in the phosphor / diffusing material layer 27, and the phosphor 30 emits fluorescence. . By mixing the fluorescence with the blue light that is not used for exciting the phosphor, white light is emitted from the light emitting device 1. Here, a part of the light emitted from the light emitting element 10 irradiates the diffusing material 31 when passing through the phosphor / diffusing material layer 27. As a result, light is diffused, and the phosphor 30 is efficiently irradiated with light. Further, color mixing of blue light from the light emitting element 10 and fluorescence from the phosphor 30 is promoted. On the other hand, since a part of the fluorescence emitted from the phosphor 30 is also diffused by the diffusion material 31 when passing through the phosphor / diffusion material layer 27, the color mixing of the fluorescence and the blue light is further promoted. As described above, since the blue light that is not used to excite the phosphor 30 and the fluorescence from the phosphor 30 are efficiently mixed in color, uneven color mixing and uneven light emission are reduced. On the other hand, the diffusing material 31 contained in the phosphor / diffusing material layer 27 reflects most of the light irradiating it toward the traveling direction. Therefore, with the above configuration, it is possible to significantly suppress the generation of light that is backward in the light extraction direction due to the reflection by the diffusing material 31. That is, the light from the light emitting element 10 or the light converted by the phosphor 30 can be efficiently advanced in the light extraction direction, and high-luminance light emission can be obtained.

In addition to the light emitting element 10, other light emitting elements can be used together. As the other light emitting element, a light emitting element having an emission wavelength different from that of the light emitting element 10 is used.
Preferably, a light emitting element having an emission wavelength that does not substantially excite the phosphor 30 to emit light is used. By using such another light emitting element, the emission color of the LED 1 can be changed or adjusted. Further, the brightness can be increased by using a plurality of light emitting elements 10.

As shown in FIG. 3, by adding the phosphor 30 and the diffusing material 31 to the sealing resin 50, the phosphor /
The diffuser-containing layer 27 can be omitted (LED
2). In FIG. 3, the same members as those in FIG. 1 are designated by the same reference numerals. Also in this case, similarly to the case of the phosphor resin layer 27, the concentration distribution of the phosphor 30 and / or the diffusing material 31 in the sealing resin 50 can be inclined.

(Embodiment 2) FIG. 4 is a schematic sectional view of an SMD type LED 3 which is another embodiment of the present invention. The same members as those of the LED 1 of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The LED 3 also emits white light as in the first embodiment, and can be used as, for example, a planar light source or a linear light source in combination with a light guide, and can also be used as various display devices. . The light emitting element 10 is the substrate 8
It is fixed to 0 using silver paste or the like. The wires 40 and 41 connect the respective electrodes of the light emitting element 10 to the electrodes 81 and 82 provided on the substrate 80, respectively. Reference numeral 90 denotes a reflector formed around the light emitting element, the surface of which is a mirror surface.

The phosphor / diffusing material-containing layer 100 and the sealing resin 85 are filled in the cup-shaped portion formed by the substrate 80 and the reflector 90. Phosphor / diffusing material-containing layer 100
Is made of an epoxy resin in which the phosphor 30 and the diffusing material 31 are dispersed. The phosphor / diffusing material-containing layer 100 is used as the light emitting element 1.
After mounting 0, it is formed by a method such as potting. The sealing resin 85 is made of an epoxy resin, and is formed by the same method as the phosphor / diffusing material containing layer 100 after forming the phosphor / diffusing material containing layer 100.

In the LED 3 configured as described above, a part of the blue light emitted from the light emitting element 10 irradiates the phosphor 30 in the phosphor / diffusing material layer 100, and the phosphor 30 emits fluorescence. . By mixing the fluorescence with the blue light that is not used for exciting the phosphor 30, white light is emitted from the LED 3. Here, as in the case of the LED 1, the diffusing material 3 in the phosphor / diffusing material-containing layer 100 is used.
By the action of 1, the color mixture of the blue light from the light emitting element 10 and the fluorescence from the phosphor is promoted, and the generation of the light which goes backward in the light extraction direction is suppressed. As a result, an LED that emits light with high brightness with less color mixture unevenness and uneven light emission is obtained.

In the LED 3 of FIG. 4, the phosphor / diffusing material-containing layer 100 and the sealing resin 85 are provided separately, but as shown in FIG. 5, the fluorescent material 30 and the diffusing material 31 are dispersed in the sealing resin 101. You may let me. In FIG. 5, the same members as those in FIG. 4 are designated by the same reference numerals.

Further, FIG. 6 shows an example in which the SMD type LED 5 without the reflector 90 is constructed. The LED 5 covers the light emitting element 10 and has a substantially rectangular cross section.
02 is formed. The sealing resin 102 is made of an epoxy resin in which the phosphor 30 and the diffusing material 31 are dispersed. Such a sealing resin 102 can be formed by molding using a desired mold. Alternatively, the sealing resin 102 molded in a desired shape may be prepared in advance, and the sealing resin 102 may be adhered to the substrate 80 so as to cover the light emitting element 10.

The present invention is not limited to the description of the embodiments and examples of the invention. Various modifications are also included in the present invention within a range that can be easily conceived by those skilled in the art without departing from the scope of the claims.

The following matters will be disclosed below. 10. The light emitting element is mounted on a cup-shaped portion provided on a lead frame, and the light-transmissive material layer is formed in the cup-shaped portion. The light-emitting device according to. 11. The light emitting element is placed on a cup-shaped portion provided on a lead frame, and the light emitting element and a part of the lead frame are covered with the light transmissive material layer. Claim 1
6. The light emitting device according to any one of 6. 12. The light emitting element according to claim 1, wherein the light emitting element is mounted on a substrate, and the light transmissive material layer is formed so as to cover the surface of the light emitting element. apparatus. 13. The light emitting device according to any one of claims 1 to 6, wherein the light emitting element is mounted on a substrate, and the light emitting element is sealed by the light transmissive material layer. 14 The light emitting element is mounted on a cup-shaped portion provided on a substrate, and the light transmissive material layer is formed in the cup-shaped portion.
The light emitting device according to claim 1, wherein the light emitting device is a light emitting device.

[Brief description of drawings]

FIG. 1 is a bullet LED 1 according to an embodiment of the present invention.
FIG.

FIG. 2 is a schematic cross-sectional view of a light emitting device 10 used for LED1.

FIG. 3 is a diagram showing an example (LED 2) in which a phosphor 30 and a diffusing material 31 are dispersed in a sealing resin 50.

FIG. 4 is a diagram showing an SMD type LED 3 according to another embodiment of the present invention.

FIG. 5 is an SM according to another embodiment of the present invention.
It is a figure which shows D type LED4.

FIG. 6 is an SM of another embodiment of the present invention.
It is a figure which shows D type LED5.

[Explanation of symbols]

1, 2 shell type LED 3, 4, 5 SMD type LED 10 Light emitting element 27,100 Phosphor / diffusing material-containing layer 30 phosphor 31 Diffuser 50, 101, 102 Sealing resin

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Sugihara             Aichi Prefecture Kasuga-cho, Nishikasugai-gun Ochiai character Nagahata 1             Address within Toyoda Gosei Co., Ltd. F-term (reference) 5F041 AA07 AA11 AA12 CA40 DA43                       EE25

Claims (6)

[Claims] 1. A light emitting device comprising: a light emitting element; and a light transmissive material layer including a phosphor that receives the light of the light emitting element and fluoresces, and a diffusion material having a refractive index distribution. 2. The light emitting element emits blue light.
The light emitting device according to claim 1. 3. The light emitting device according to claim 1, wherein the light emitting element emits blue light, and the blue light and fluorescence from the phosphor are mixed to emit white light. Light emitting device. 4. The light emitting device according to claim 1, wherein the light emitting element emits light in the ultraviolet region. 5. The light emitting device emits light in the ultraviolet region,
And each of the phosphors includes a fluorescent material that emits red-based, green-based, and blue-based fluorescence, and by mixing the fluorescence emitted from the phosphors,
The light emitting device according to claim 1, which emits white light. 6. The light emitting device according to claim 1, wherein the light emitting element is a group III nitride compound semiconductor light emitting element.