Light-emitting apparatus

[Industrial Application Field] The present invention relates to a light emitting device. More specifically, the present invention relates to a light emitting device in which a light emitting element that emits light in the ultraviolet region and a phosphor are combined.

PROBLEM TO BE SOLVED: To emit a light emitting device having a color different from the original light emitting color of the light emitting element by combining a light emitting element and a phosphor which is excited by the light of the light emitting element and emits fluorescence. There is. In particular, with the development of a light emitting element capable of emitting light in the ultraviolet region, a light emitting device capable of emitting high brightness light by utilizing the high energy light emitted by the light emitting element for exciting a phosphor is used. Development is being attempted. As a light emitting device in which a light emitting element that emits light in the ultraviolet region and a phosphor is combined, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 2000-208818. The publication proposes a light emitting device having a structure in which a light emitting element that emits light in an ultraviolet region is sealed with a silicone resin in which an organic phosphor is dispersed.

[0003] When light in an ultraviolet region is used, it is necessary to particularly consider photodegradation of a member that seals a light emitting element. In the light emitting device described in the above publication, silicone resin, which is a material that is not easily deteriorated by light in the ultraviolet region, is used as the sealing member to prevent photodegradation of the sealing member. However, the silicone resin is a softer material than a general epoxy resin as a sealing member for a light emitting element, and has low durability against an external impact. Therefore, the impact resistance and durability of the light emitting device are lowered. On the other hand, although an organic phosphor is used in the above-mentioned light emitting device, the organic phosphor is generally considered to have high light conversion efficiency, but has high reactivity with oxygen and the like, and is easily oxidatively deteriorated. Therefore, when the organic phosphor is uniformly dispersed in the sealing member as in the above-mentioned light emitting device, a part of the phosphor is exposed to the outside, which causes a problem of deterioration due to oxidation. Deterioration of the phosphor causes a decrease in the brightness of the light emitting device and a change in the emission color. In particular, when the light emitting element emits light in the visible region in addition to light in the ultraviolet region used for exciting the phosphor, and the light and the fluorescence of the phosphor are mixed and emitted to the outside, the phosphor The color balance is lost due to the deterioration of the light, and the change in the emission color of the externally radiated light becomes remarkable. Here, it is also possible to coat the silicone resin in which the organic phosphor is dispersed with an epoxy resin to improve the strength against external impact and prevent the oxidative deterioration of the organic phosphor. In this case, The phosphor exposed on the surface of the silicone resin reacts with the epoxy resin, and problems such as a decrease in brightness and a change in emission color due to deterioration of the phosphor resurface. Further, in general, it is difficult to adjust the addition amount of an organic phosphor as compared with an inorganic phosphor due to its properties, and it is difficult to manufacture a light emitting device having a uniform emission color.

[Means for Solving the Problems] As a result of diligent studies to solve the above problems, the present inventors have come up with the following configuration. That is, the present invention contains a light emitting element having a main emission peak wavelength of 450 nm or less, a sealing member that covers the light emitting side of the light emitting element, and an organic phosphor, and is added to the sealing member. A light emitting device including a silicone member.

[0005] In such a configuration, since the organic phosphor is added to the sealing member in a state of being contained in the silicone, a material having excellent impact resistance such as an epoxy resin can be adopted as the sealing member. Therefore, it is possible to configure a light emitting device having high impact resistance and durability. Further, since the sealing member covers the silicone member containing the organic phosphor, the deterioration of the phosphor due to the exposure of the organic phosphor to the outside can be suppressed as much as possible. Further, although the organic phosphor is present in the sealing member, it is contained in the silicone member, so that the reaction between the sealing member and the organic phosphor is suppressed, and the fluorescence due to such a reaction is suppressed. Deterioration of the body is also suppressed. In this way, it is possible to prevent deterioration of the phosphor due to the external environment and the sealing member, and the light emitting device has little change in emission color with time. Further, by incorporating the organic phosphor in the silicone member, the handleability is improved and the amount of the phosphor added can be easily adjusted. Therefore, it is possible to manufacture a light emitting element having the same quality (emission color).

[Embodiment] A light emitting device having a main light emitting peak wavelength in a wavelength region of 500 nm or less is used. That is, a light emitting element that emits light in the blue to ultraviolet region is used. Preferably, a light emitting device having a main emission peak wavelength of 450 nm or less is used. For example, a light emitting element having a main emission peak wavelength in the range of 360 nm to 450 nm, a light emitting element having a main emission peak wavelength in the range of 360 to 410 nm, and the like can be used. More preferably, a light emitting device having a main emission peak wavelength in the range of 360 nm to 400 nm can be adopted. Light in the above wavelength region can excite and emit light of a phosphor described later with high efficiency. Of course, a light emitting element having one or more emission peak wavelengths in a wavelength region different from the above wavelength region can also be adopted. Further, a light emitting element having a plurality of light emitting peaks in the above wavelength region may be adopted. 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 is used for exciting the phosphor, while the light in the visible region is one of the light of the external radiation. It can be used as a department. In this way, the light emitting device emits light that is a mixture of the fluorescence of the phosphor and the visible light emitted from the light emitting element. For example, by adopting a light emitting element capable of emitting ultraviolet light and blue light and combining phosphors that emit fluorescence such as green or red by ultraviolet light, a light emitting device having various emission colors can be configured. be able to. In selecting the light emitting element, the excitation peaks and fluorescent colors of the phosphors (organic and inorganic) described later, and the color of the light emitted from the entire light emitting device are taken into consideration. A plurality of light emitting elements can also be used. In this case, light emitting elements having different emission wavelengths (emission colors) can be used, whereby the emission color of the entire light emitting device can be changed and adjusted.

[0007] The material for forming the light emitting element is not particularly limited. A light emitting device provided with a group III nitride compound semiconductor layer, that is, a group III nitride compound semiconductor light emitting device can be preferably used. Group III nitride compound semiconductors have a general formula of Al._XGa_YIn_1-XYIt is represented by N (0 X 1, 0 Y 1, 0 X + Y 1), and is a so-called binary system of AlN, GaN and InN, Al._xGa_1-xN, Al_xIn_1-xN and Ga_xIn_1-xIt includes the so-called ternary system of N (in the above, 0 <x <1). Part of group III elements may be replaced with boron (B), thallium (Tl), etc., and part of nitrogen (N) is also phosphorus (P), arsenic (As), antimony (Sb), bismuth. It can be replaced with (Bi) or the like. The element functional portion of the light emitting device is preferably composed of the above-mentioned binary or ternary group III nitride compound semiconductor.

[0008] The group III nitride compound semiconductor may contain any dopant. As the n-type impurity, Si, Ge, Se, Te, C and the like can be used. As the p-type impurity, Mg, Zn, Be, Ca, Sr, Ba and the like can be used. After doping with p-type impurities, the group III nitride compound semiconductor can be exposed to electron beam irradiation, plasma irradiation, or heating by a furnace. Group III nitride compound semiconductors include organic metal vapor phase growth method (MOCVD method), well-known molecular beam crystal growth method (MBE method), halide-based vapor phase growth method (HVPE method), sputtering method, and ion play. It can also be formed by a ting method, an electronic shower method, or the like.

[0009] 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, etc. 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.

[0010] As the sealing member, an epoxy resin, a silicone resin, a silicone rubber, a silicone elastomer, a urea resin, glass or the like is used. These materials are not only used alone, but also two or more kinds of materials arbitrarily selected from these can be used. Above all, it is preferable to use an epoxy resin from the viewpoint of ease of handling and versatility. When a silicone resin, silicone rubber, or silicone elastomer is used, it is preferable to coat the surface (externally exposed surface) 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.

[0011] The sealing member is arranged so as to cover the light emitting side of the light emitting element. Therefore, the light emitted from the light emitting element is radiated to the outside through the sealing member. A layer made of a material different from that of the sealing member can be provided between the light emitting element and the sealing member. For example, a silicone resin can be applied to the surface of the light emitting element, and a sealing member made of an epoxy resin or the like can be formed on the surface. A light diffusing agent can also be added to the sealing member. The use of a light diffusing agent promotes the diffusion of light in the sealing member. Therefore, the light of the light emitting element can be efficiently irradiated to the phosphor. Further, when the light emitting element also emits visible light, or when a plurality of phosphors are used, it is possible to promote color mixing of visible light from the light emitting element, fluorescence from each phosphor, and the like, and reduction of light emission unevenness can be achieved. .. As the light diffusing agent, titanium oxide, titanium nitride, tantalum nitride, aluminum oxide, silicon oxide, barium titanate and the like can be used. Further, a colorant can be added to the sealing member. The colorant is used to prevent the organic phosphor itself and the like from exhibiting a peculiar color.

[0012] A silicone member containing an organic phosphor is added to the sealing member. The type of organic phosphor used is not particularly limited as long as it is excited by the light of a light emitting element and emits fluorescence. The following can be adopted as the organic phosphor. For example, stilbene dyes such as 1,4-bis (2-methylstyryl) benzene (Bis-MSB), trans-4,4'-diphenylstilbene (DPS), and 7-hydroxy-4-methylcoumarin (coumarin 4). ) And other coumarin dyes, BOQP, PBBO, BOT, POPOP and the like can be used. These phosphors have a bluish emission color. In addition, DPOT, brilliantsulfoflavin FF, basic yellow HG, SINLOIHI COLOR FZ-5005 (manufactured by Shinroihi), etc. can also be used. These phosphors have a yellowish to greenish fluorescent color. In addition, yellow to red phosphors such as eosin (eosine), rhodamine 6G (rhodamine 6G), and rhodamine B (rhodamine) B), NKP-8303 (manufactured by Nippon Fluorescent Chemical Co., Ltd.), etc. can also be used. Further, TB (EDTA) SSA, EuTTA and the like may be dissolved in, for example, methyl methacrylate, polymerized and solidified to obtain polymethyl methacrylate (PMMA). It should be noted that a plurality of types of organic phosphors can be used in combination. In this case, a plurality of types of organic phosphors may be mixed and contained in the silicone member, or each organic phosphor may be contained in different silicone members.

[0013] As the silicone, a silicone resin, a silicone rubber, or a silicone elastomer can be used. Above all, it is preferable to use a silicone resin.

[0014] The silicone member containing the organic phosphor can be prepared, for example, by impregnating the cured silicone with the organic phosphor, or by mixing the uncured silicone with the organic phosphor. .. In the former case, silicone is molded in advance into an appropriate shape and size, and the surface of the obtained silicone molded body is impregnated with an organic phosphor. For example, the silicone molded product is immersed in a solution in which an organic phosphor is dissolved for a certain period of time. On the other hand, in the latter case, an organic phosphor is mixed with the silicone before curing, and then the silicone is cured so as to have an appropriate shape and size. The shape and size of the silicone member are not particularly limited, but in consideration of handleability, it is preferably spherical (ball-shaped) and has a diameter of 1 to 50 μm. Regarding the size, it is more preferable that the diameter is 1 to 10 μm. Here, since the size of a general inorganic phosphor is several μm, if a silicone member having a size in the above range is used, it can be handled in the same manner as an inorganic phosphor. This makes it easy to adjust the amount of the silicone member added, that is, the amount of the organic phosphor added, and when an inorganic phosphor is also used as described later, the amount of the organic phosphor is different from that of the organic phosphor. This means that the amount of each addition of the inorganic phosphor can be easily adjusted.

[0015] The silicone member containing the organic phosphor is added in a state of being uniformly dispersed in the sealing member or in a state of being localized in a part of the region. By localizing the silicone member on the light emitting element side, it is possible to efficiently irradiate the organic phosphor with the light from the light emitting element. To localize and add to the light emitting element side, for example, the surface of the light emitting element (light emitting side) is coated with a small amount of sealing member in which the silicone member is dispersed, and the sealing member does not contain the silicone member. Laminate the members. Here, by preparing a plurality of sealing members having different addition amounts of silicone members and laminating them in order, the amount of silicone member added (that is, the amount of organic phosphor added) gradually changes as the distance from the light emitting element side increases. It may be. Furthermore, a plurality of sealing members to which silicone members containing different types of organic phosphors are added can be prepared, and these can be laminated in order.

[0016] Inorganic phosphors can be used in addition to organic phosphors. The inorganic phosphor can be used in a state of being added to the above-mentioned sealing member. Further, different sealing members may be prepared and used in a state of being added thereto. For example, when a plurality of phosphors are used and these fluorescences are mixed and radiated to the outside, more efficient fluorescence can be obtained by using an inorganic fluorescent substance than by using an organic fluorescent substance for a specific fluorescent color. When this is the case, it is preferable to use an inorganic phosphor for the specific fluorescent color. For example, a red-based organic phosphor and a green-based to blue-based inorganic phosphor can be used in combination. By adopting an appropriate phosphor having good excitation efficiency according to the fluorescence color, the light of the light emitting element can be efficiently used, and the brightness of the light emitting device can be improved. The following can be adopted as the inorganic phosphor. For example, 6MgO As having a red emission color₂O₅: Mn⁴⁺, Y (PV) O₄: Eu, CaLa_0.1EU_0.9Ga₃O₇, BaY_0.9Sm_0.1Ga₃O₇, Ca (Y_0.5EU_0.5) (Ga_0.5In_0.5)₃O₇, Y₃O₃: Eu, YVO₄: Eu, Y₂O₂: Eu, 3.5MgO / 0.5MgF₂GeO₂: Mn⁴⁺, And (Y Cd) BO₂: Has a bluish emission color such as Eu (Ba, Ca, Mg)₅(PO₄)₃Cl: Eu²⁺, (Ba, Mg)₂Al₁₆O₂₇:EU²⁺, Ba₃MgSi₂O₈:EU²⁺, BaMg₂Al₁₆O₂₇:EU²⁺, (Sr, Ca)₁₀(PO₄)₆Cl₂:EU²⁺ , (Sr, Ca)₁₀(PO₄)₆Cl₂ NB₂O₃:EU²⁺, Sr₁₀(PO₄)₆Cl₂:EU²⁺, (Sr, Ba, Ca)₅(PO₄)₃Cl: Eu²⁺, Sr₂P₂O₇: Eu, Sr₅(PO₄)₃Cl: Eu, (Sr, Ca, Ba)₃(PO₄)₆Cl: Eu, SrO P₂O₅ B₂O₅: Eu, (BaCa)₅(PO₄)₃Cl: Eu, SrLa_0.95Tm_0.05Ga₃O₇, ZnS: Ag, GaWO₄, Y₂SiO₆: Ce, ZnS: Ag, Ga, Cl, Ca₂B₄OCl: Eu²⁺, BaMgAl₄O₃:EU²⁺, And general formula (M1, Eu)₁₀(PO₄)₆Cl₂Y having a greenish emission color such as a phosphor represented by (M1 is at least one element selected from the group consisting of Mg, Ca, Sr, and Ba).₂SiO₅: Ce³⁺, Tb³⁺, Sr₂Si₃O₈ 2SrCl₂: Eu, BaMg₂Al₁₆O₂₇:EU²⁺, Mn²⁺, ZnSiO₄: Mn, Zn₂SiO₄: Mn, LaPO₄: Tb, SrAl₂O₄: Eu, SrLa_0.2Tb_0.8Ga₃O₇, CaY_0.9Pr_0.1Ga₃O₇, ZnGd_0.8Ho_0.2Ga₃O₇, SrLa_0.6Tb_0.4Al₃O₇, ZnS: Cu, Al, (Zn, Cd) S: Cu, Al, ZnS: Cu, Au, Al, Zn₂SiO₄: Mn, ZnSiO₄: Mn, ZnS: Ag, Cu, (Zn Cd) S: Cu, ZnS: Cu, GdOS: Tb, LaOS: Tb, YSiO₄: Ce Tb, ZnGeO₄: Mn, GeMgAlO: Tb, SrGaS: Eu²⁺, ZnS: Cu Co, MgO nB₂O₃: Ge, Tb, LaOBr: Tb, Tm, and La₂O₂S: Tb etc. can be used. In addition, YVO has a white emission color.₄: Dy, CaLu with yellowish emission color_0.5Dy_0.5Ga₃O₇Can also be used.

[0017] In addition to the above sealing member, a second sealing member can be used. The second sealing member is formed between the light emitting element and the sealing member (hereinafter, also referred to as first sealing member) or so as to cover the surface of the sealing member. As the material of the second sealing member, an epoxy resin, a silicone resin, a urea resin, glass or the like can be adopted as in the case of the first sealing member. For example, the first sealing member is formed of a silicone resin, and the second sealing member made of an epoxy resin is formed so as to cover the first sealing member. The second sealing member may also contain a phosphor (including organic and inorganic), a light diffusing agent, and / or a colorant. Further, the second sealing member may contain an ultraviolet absorber. In this way, the light in the ultraviolet region that is not used for exciting the phosphor can be absorbed by the second sealing member, and the light in the ultraviolet region can be prevented from being emitted to the outside. As the ultraviolet absorber, for example, 2- (2-hydroxy-3,5-di-t-butylphenyl) -5-chlorobenzotriazole or the like can be used.

[Example] The configuration of the present invention will be described in more detail with reference to the following examples. (Example 1) FIG. 1 is a diagram showing a cannonball type LED 1 which is an embodiment of the present invention. LED1 emits white light and can be used as a planar light source or a linear light source in combination with a light guide, and can also be used in various display devices and the like. FIG. 2 shows a schematic cross-sectional view of the light emitting element 10 used for the LED 1. The light emitting element 10 has a structure in which a plurality of group III nitride compound semiconductor layers are laminated on a sapphire substrate, and has a light emitting peak wavelength in the vicinity of 380 nm. The specifications of each layer of the light emitting element 10 are as follows.<img file="JP4114331B2_D0001.tif" />[0019] An n-type layer 13 made of Si-doped GaN with n-type impurities was formed on the substrate 11 via the buffer layer 12. Here, sapphire was used for the substrate 11, but the substrate is not limited to sapphire, spinel, silicon, silicon carbide, zinc oxide, gallium phosphide, gallium arsenide, magnesium oxide, manganese oxide, and group III. A nitride-based compound semiconductor single crystal or the like can be used. Further, the buffer layer is formed by the MOCVD method using AlN, but the present invention is not limited to this, and GaN, InN, AlGaN, InGaN, AlInGaN and the like can be used as the material, and molecular beam crystal growth is used as the production method. A method (MBE method), a halide-based vapor phase growth method (HVPE method), a sputtering method, an ion plating method, an electron shower method, or the like can be used. When a group III nitride compound semiconductor is used as a substrate, the buffer layer can be omitted. Further, the substrate and the buffer layer can be removed, if necessary, after the semiconductor element is formed. Here, the n-type layer 13 is formed of GaN, but AlGaN, InGaN, or AlInGaN can be used. Further, the n-type layer 13 is doped with Si as an n-type impurity, but Ge, Se, Te, C and the like can also be used as the n-type impurity. The n-type layer 13 can have a two-layer structure including 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. The layer 14 including the light emitting layer may include a quantum well structure (multiple quantum well structure or single quantum well structure), and the structure of the light emitting element includes a single heterotype, a double heterotype, and homozygosity. It may be a type. The layer 14 including the light emitting layer can also include a group III nitride compound semiconductor layer having a wide bandgap doped with an acceptor such as magnesium on the side of the p-type layer 15. This is to effectively prevent the electrons injected into the layer 14 including the luminescent layer from diffusing into the p-type layer 15. Dope Mg as a p-type impurity on the layer 14 including the luminescent layer A p-type layer 15 made of GaN was formed. The p-type layer can be AlGaN, InGaN or InAlGaN, and Zn, Be, Ca, Sr, and Ba can be used as the p-type impurities. Further, a two-layer structure including a low hole concentration p-layer on the layer 14 side including a layer that emits light from the p-type layer 15 and a high hole concentration p + layer on the electrode side can be formed. In the light emitting diode having the above configuration, each group III nitride compound semiconductor layer is formed by performing MOCVD under general conditions, or a molecular beam crystal growth method (MBE method) or a halide-based vapor phase growth method (HVPE method). ), Spatter method, ion plating method, electronic shower method and the like.

[0020] The n-electrode 19 is composed of two layers, Al and V, and after forming the p-type layer 15, the p-type layer 15, the layer 14 including the light emitting layer, and a part of the n-type layer 13 are etched. It is removed and formed on the n-type layer 13 by vapor deposition. The translucent 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 forming each semiconductor layer and each electrode by the above steps, a separation step of each chip is performed.

[0021] It is also possible to provide a reflective layer between the layer 14 including the 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 toward the substrate side can be efficiently reflected in the light extraction direction, and as a result, the luminous efficiency can be improved. The reflective layer can be formed of one or more selected from titanium nitride, zirconium nitride, and tantalum nitride. In addition, a simple substance of a metal such as Al, In, Cu, Ag, Pt, Ir, Pd, Rh, W, Mo, Ti, Ni or an alloy consisting of two or more kinds of metals arbitrarily selected from these is used. It is also possible to form a reflective layer.

[0022] The light emitting element 10 is mounted on the cup-shaped portion 25 provided on the lead frame 20 by using an adhesive. The adhesive is a silver paste in which silver is mixed as a filler in an epoxy resin. By using such a silver paste, heat is better dissipated from the light emitting element 10. Instead of the silver paste, another known adhesive such as a transparent paste or a 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 31 and 30 by wires 41 and 40, respectively. Subsequently, the cup-shaped portion 25 is filled with an epoxy resin 27 (hereinafter referred to as fluorescent resin layer 27) in which silicone balls 30, 31, and 32 impregnated with different organic phosphors are uniformly dispersed. Will be done. Silicone balls 30, 31 and 32 have red organic phosphor NKP-8303 (manufactured by Nippon Fluorescent Chemicals), green organic phosphor SINLOIHI COLOR FZ-5005 (manufactured by Shinroihi), and blue, respectively. It is impregnated with the organic fluorophore 1,4-bis (2-methylstyryl) benzene (Bis-MSB). Silicone balls 30, 31, and 32 are produced by the following methods. First, liquid silicone is cured while being molded into a spherical shape (silicone ball) having a diameter of about 5 μm. The obtained silicone ball is immersed in a solution in which the organic phosphor to be impregnated is dissolved for about 3 hours. The immersion time is appropriately adjusted in consideration of the impregnation efficiency.

[0024] The amount of each of the silicone balls 30, 31, and 32 added to the epoxy resin is the amount of each organic phosphor impregnated in each silicone ball, the fluorescence efficiency of each organic phosphor, the emission color of the light emitting device 1, and the like. Determined in consideration. In this embodiment, three types of organic phosphors of red, green, and blue are used, but only one type or two types of organic phosphors can be used depending on the required emission color. .. The phosphor resin layer 27 is formed by mounting the light emitting element 10 and then potting an epoxy resin in which silicone balls 30, 31, and 32 are dispersed on the cup portion 25. In addition to potting, the fluorescent resin layer 27 can also be formed by sputtering, coating, painting, or the like.

[0025] A phosphor resin layer that coats the surface of the light emitting element 10 may be formed. For example, the light emitting element 10 is dipped in an epoxy resin in which silicone balls 30, 31, and 32 are dispersed, the surface of the light emitting element 10 is coated with a phosphor layer, and then the light emitting element 10 is mounted on the cup portion 25. The surface of the surface can be coated with a phosphor resin. In addition to the above dipping, the same coating can be performed by sputtering, coating, painting, or the like.

[0026] In this embodiment, an epoxy resin is used as a base material for dispersing the silicone balls 30, 31, 32, but the present invention is not limited to this, and silicone (silicone resin, silicone rubber, or silicone elastomer), urea. A transparent material such as resin or glass can be used. Further, in this embodiment, the silicone balls 30, 31, and 32 are uniformly dispersed in the phosphor resin layer 27, but the concentration distribution of the silicone balls 30, 31, and 32 in the phosphor resin layer 27 is changed. A slope can also be provided. For example, epoxy resins having different addition concentrations of silicone balls 30, 31, and 32 are laminated on the light emitting element 10 in order. Further, all the silicone balls were dispersed in one epoxy resin to form a phosphor layer, but each epoxy resin in which each silicone ball was dispersed was prepared and dropped separately on the cup-shaped portion 25. Therefore, it is also possible to form a phosphor resin layer in which resins in which different silicone balls are dispersed are laminated.

[0027] The phosphor resin layer 27 may contain a diffusing agent made of titanium oxide, titanium nitride, tantalum nitride, aluminum oxide, silicon oxide, barium titanate, or the like.

[0028] The light emitting element 10, a part of the lead frames 30 and 31, and the wires 40 and 41 are sealed with a sealing resin 50 made of an epoxy resin. The material of the sealing resin 50 is not particularly limited as long as it is transparent, but an epoxy resin can be preferably used as the material. Further, from the viewpoint of adhesiveness to the fluorescent resin layer 27, refractive index, etc., it is preferable that the material is the same as that of the fluorescent resin layer 27.

[0029] Although the sealing resin 50 is provided for the purpose of protecting the element structure or the like, the 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 bullet type shown in FIG. 1, it can be molded into a concave lens type, a convex lens type, or the like. Further, the shape of the sealing resin 50 can be circular, elliptical, or rectangular when viewed from the light extraction direction (upper in FIG. 1). Silicone balls 30, 31, and 32 can also be dispersed in the sealing resin 50.

[0030] A diffusing agent (not shown) and an ultraviolet absorber (not shown) are dispersed in the sealing resin 50. By using a diffusing agent, light diffusion and color mixing can be promoted in the sealed resin, and light emission unevenness can be reduced. As the diffusing agent, titanium oxide, titanium nitride, tantalum nitride, aluminum oxide, silicon oxide, barium titanate and the like are used. On the other hand, by using an ultraviolet absorber, it is possible to prevent ultraviolet rays that have not been used for exciting the phosphor from being emitted to the outside. It should be noted that either or both of the diffusing agent and the ultraviolet absorbing agent may be omitted.

As shown in FIG. 3, the fluorescent resin layer 27 can be omitted by adding the silicone balls 30, 31, and 32 to the sealing resin 50. In FIG. 3, the same members as those in FIG. 1 are designated by the same reference numerals. In this case as well, the concentration distribution of the silicone balls 30, 31, and 32 can be inclined in the sealing resin 50, as in the case of the phosphor resin layer 27.

[0032] In the LED 1 configured as described above, the light in the ultraviolet region emitted from the light emitting element 10 irradiates the organic phosphors impregnated with the silicone balls 30, 31 and 32, and each organic phosphor is irradiated. Excite and emit light. As a result, red, green, and blue fluorescence is generated. Such fluorescence and a small amount of visible light emitted from the light emitting element 10 are mixed and emitted to the outside. As a result, white light emission can be obtained from LED1.

[0033] In addition to the light emitting element 10, other light emitting elements may be used. As another light emitting element, a light emitting element having a different emission wavelength from that of the light emitting element 10 is used. By using such another light emitting element, the light emitting color of LED1 can be changed or adjusted. It is also possible to increase the brightness by using a plurality of light emitting elements 10.

(Example 2) FIG. 4 is a cross-sectional view of an SMD type LED 3 which is another embodiment of the present invention. The same members as LED 1 of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. LED3 also emits white light as in Example 1, and can be used for a planar light source, a linear light source, etc. in combination with a light guide, and can also be used for various display devices and the like. .. The light emitting element 10 is fixed to the substrate 80 using a silver paste or the like. The wires 40 and 41 connect the electrodes of the light emitting element 10 to the electrodes 81 and 82 provided on the substrate 80, respectively. Reference numeral 90 is a reflector formed around the light emitting element, the surface of which is mirrored.

[0035] The cup-shaped portion formed by the substrate 80 and the reflector 90 is filled with the phosphor resin layer 100 and the sealing resin 85. The phosphor resin layer 100 is made of a silicone resin in which silicone balls 30, 32 and an inorganic phosphor 37 are dispersed. As described above, the silicone balls 30 and 32 are made of a spherical silicone resin impregnated with a red-based organic phosphor and a blue-based phosphor, respectively. Inorganic phosphor 37 is green Y₂SiO₅: Ce³⁺, Tb³⁺Is. The phosphor resin layer 100 is formed by a method such as potting after mounting the light emitting element 10. The sealing resin 85 is made of an epoxy resin, and after forming the phosphor resin layer 100, it is formed by the same method as that of the phosphor resin layer 100.

[0036] In the LED 3 configured as described above, when the light in the ultraviolet region emitted from the light emitting element 10 passes through the phosphor resin layer 100, the organic phosphors and inorganics impregnated in the silicone balls 30 and 33 are incorporated. The system phosphor 37 is excited to emit light. The fluorescence generated by this and the visible light emitted from the light emitting element are mixed, and white light is emitted to the outside as a whole.

In LED3 of FIG. 4, the phosphor resin layer 100 and the sealing resin 85 are separately provided, but as shown in FIG. 5, the sealing resin 101 is provided with silicone balls 31, 33, and the inorganic phosphor 37. May be dispersed. In FIG. 5, the same members as those in FIG. 4 are designated by the same reference numerals.

[0038] Further, FIG. 6 shows an example in which an SMD type LED that does not use the reflector 90 is configured. In LED5, a sealing resin 102 having a substantially rectangular cross section is formed by covering the light emitting element 10. The sealing resin 102 is made of an epoxy resin in which silicone balls 31, 33 and an inorganic phosphor 37 are dispersed. Such a sealed resin 102 can be formed by mounting the light emitting element 10 on the substrate and then molding the light emitting element 10 using a desired mold. Further, the sealing resin 102 molded into a desired shape may be prepared in advance and adhered to the substrate 80 so as to cover the light emitting element 10.

[0039] Similar to the case of LED1 of the first embodiment, the sealing resin 85 of LED3 of FIG. 4, the phosphor resin layer 100 and / or the sealing resin 85 of LED4 of FIG. 5, and the LED5 of FIG. The sealing resin 102 may contain any or a combination of two or more of a diffusing agent and an ultraviolet absorber.

[0040] The present invention is not limited to the description of the embodiments and examples of the above invention. Various modifications are also included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a bullet-shaped LED 1 according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a light emitting element 10 used in LED 1.

FIG. 3 is a diagram showing an example (LED2) in which silicone balls are dispersed in a sealing resin 50.

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

FIG. 5 is a diagram showing an SMD type LED 4 which is also another embodiment of the present invention.

FIG. 6 is a diagram showing an SMD type LED 5 which is also another embodiment of the present invention.

[Description of Code] 1, 2 Bullet-shaped LED 3, 4, 5 SMD type LED 10 Light emitting element 27, 100 Fluorescent resin layer 30, 31, 32 Silicone ball containing organic phosphor 37 Inorganic phosphor 50, 101, 102 Sealed Stop resin