JP4418685B2 - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device comprising a fluorescent layer of novel configuration charged tightly with fluorescent particles for obtaining uniform fluorescence. <P>SOLUTION: In the light emitting device comprising a light emitting element and a fluorescent layer which becomes fluorescent by being excited with light emitted from the light emitting element, phosphor particles themselves are linked by a translucent organic link layer to substantially continue the phosphor particles. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to an improvement of a light emitting device having a light emitting element and a fluorescent layer.

Conventionally, there has been proposed a light emitting device that converts the wavelength of light emitted from a light emitting element with a fluorescent material to obtain a desired emission color. For example, Patent Document 1 proposes a light emitting device having a configuration in which a light emitting element is covered with a resin sealing member (phosphor layer) in which particulate phosphors are dispersed. However, in general, although the phosphor material is easily deteriorated by moisture, the resin constituting the phosphor layer has a hygroscopic property, so that the phosphor cannot be sufficiently prevented from being deteriorated by moisture.
Therefore, it has been proposed to use an inorganic material in place of the resin and disperse the phosphor therein (also see paragraph 15 of Patent Document 1). Thereby, deterioration of the phosphor due to moisture can be prevented.
Moreover, please refer to patent documents 2-9 as a technique relevant to this invention.

JP 2001-217466 A Japanese Patent Laid-Open No. 2001-214093 JP 2002-208733 A Japanese Patent Laid-Open No. 2002-203989 JP 2002-134790 A Japanese Patent No. 3307316 Japanese Patent No. 3337000 Japanese Patent No. 3230158 Japanese Patent No. 2924961

The present inventors have repeatedly studied to improve the fluorescent layer in the light emitting device, and have found the following problems to be improved.
When an inorganic material is selected as a material for dispersing the phosphor, for example, it is impossible to disperse the phosphor in a general-purpose glass. This is because the phosphor is destroyed at the softening temperature of the glass. Therefore, glass with a low softening temperature (low melting point glass) will be used, but in a temperature range where the phosphor does not have a thermal effect, even in the softened state, the fluidity is extremely low and the phosphor particles are evenly dispersed. It is difficult to do. Further, the amount of phosphor particles that can be mixed into the glass is also limited. Therefore, the fluorescent layer becomes thick in order to secure a phosphor necessary for obtaining sufficient fluorescence. Therefore, there is a difference in the amount of light received from the light emitting element per unit volume between the lower layer of the fluorescent layer (on the light emitting element side) and the upper layer of the fluorescent layer (on the light emission surface side). As a result, the distribution of the wavelength spectrum differs between the light emitted from the lower layer and the upper layer, and color unevenness may occur depending on the observation direction.

  In the present invention, the phosphor particles are not dispersed in a dispersion medium such as glass, but the phosphor particles themselves are connected by the translucent inorganic connecting layer so that the phosphor particles are substantially continuous with each other. did.

Thereby, the phosphor particles are uniformly and densely packed in the phosphor layer, and the phosphor amount per unit volume is maximized. Therefore, it is possible to extract sufficient fluorescence even with a thin fluorescent layer, the wavelength of light from the light emitting element can be converted with high efficiency, and the wavelength spectrum of the fluorescence can be stably prevented from causing color unevenness.
Since all of the constituent elements of such a light emitting device can be formed of an inorganic material, the light emitting device can be subjected to a heat treatment process such as a solder reflow furnace.

Hereafter, each element of this invention is demonstrated in detail.
(Light emitting element)
The light emitting elements include light emitting diodes, laser diodes and other light emitting elements. The light emitting / receiving wavelength of the light emitting element is not particularly limited, and a group III nitride compound semiconductor element effective for ultraviolet to green light and a GaAs semiconductor element effective for red light can be used.
What emits ultraviolet rays used in the examples is a group III nitride compound semiconductor light emitting device. Here, III nitride compound semiconductor is represented by the general formula _{Al X Ga Y In 1-X} -Y N (0 <X ≦ 1,0 ≦ Y ≦ 1,0 ≦ X + Y ≦ 1). Among them, those containing Al include a so-called binary system of AlN and a so-called ternary system of Al _x Ga _1-x N and Al _x In _1-x N (where 0 <x <1). In the group III nitride compound semiconductor and GaN, at least part of the group III element may be replaced with boron (B), thallium (Tl), etc., and at least part of nitrogen (N) may be phosphorus (P ), Arsenic (As), antimony (Sb), bismuth (Bi) and the like.
Further, the group III nitride compound semiconductor may contain an arbitrary dopant. As the n-type impurity, silicon (Si), germanium (Ge), selenium (Se), tellurium (Te), carbon (C), or the like can be used. As the p-type impurity, magnesium (Mg), zinc (Zr), beryllium (Be), calcium (Ca), strontium (Sr), barium (Ba), or the like can be used. Although the group III nitride compound semiconductor can be exposed to electron beam irradiation, plasma irradiation or furnace heating after doping with p-type impurities, it is not essential.
The group III nitride compound semiconductor layer is formed by MOCVD (metal organic chemical vapor deposition). It is not necessary to form all the semiconductor layers constituting the element by the MOCVD method, and the molecular beam crystal growth method (MBE method), halide vapor phase epitaxy method (HVPE method), sputtering method, ion plating method, etc. are used in combination. Is possible.

  As a structure of the light-emitting element, a homostructure, a heterostructure, or a double heterostructure having a MIS junction, a PIN junction, or a pn junction can be used. A quantum well structure (single quantum well structure or multiple quantum well structure) can also be adopted as the light emitting layer. As such a group III nitride compound semiconductor light emitting device, a face-up type in which the main light receiving and emitting direction (electrode surface) is the optical axis direction of the optical device, and the reflected light with the main light receiving and emitting direction opposite to the optical axis direction. A flip chip type using the above can be used.

(Phosphor particles)
As the phosphor particles, those generally used in light emitting devices such as a combination of a blue light emitting element and a YAG phosphor can be used as they are.
For example, the following can be adopted as the inorganic phosphor. For example, 6MgO.As ₂ O ₅ : Mn ⁴⁺ having a red emission color, Y (PV) O ₄ : Eu, CaLa _0.1 Eu _0.9 Ga ₃ O ₇ , BaY _0.9 Sm _0.1 Ga _{3 O 7, Ca (Y 0.5} Eu 0.5) (Ga 0.5 In 0.5) 3 O 7, Y 3 O 3: Eu, YVO 4: Eu, Y 2 O 2: Eu, 3. (Ba, Ca, Mg) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ having a blue emission color, such as 5MgO · 0.5MgF ₂ GeO ₂ : Mn ⁴⁺ and (Y · Cd) BO ₂ : Eu Ba, Mg) ₂ Al ₁₆ O ₂₇ : Eu ²⁺ , Ba ₃ MgSi ₂ O ₈ : Eu ²⁺ , BaMg ₂ Al ₁₆ O ₂₇ : Eu ²⁺ , (Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺
, (Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ .nB ₂ O ₃ : Eu ²⁺ , Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , (Sr, Ba, Ca) ₅ (PO ₄ ) ₃ Cl : Eu ²⁺ , Sr ₂ P ₂ O ₇ : Eu, Sr ₅ (PO ₄ ) ₃ Cl: Eu, (Sr, Ca, Ba) ₃ (PO ₄ ) ₆ Cl: Eu, SrO · P ₂ O ₅ · B ₂ O ₅ : Eu, (BaCa) ₅ (PO ₄ ) ₃ Cl: Eu, SrLa _0.95 Tm _0.05 Ga ₃ O ₇ , ZnS: Ag, GaWO ₄ , Y ₂ SiO ₆ : Ce, ZnS: Ag, Ga , Cl, Ca ₂ B ₄ OCl: Eu ²⁺ , BaMgAl ₄ O ₃ : Eu ²⁺ , and the general formula (M1, Eu) ₁₀ (PO ₄ ) ₆ Cl ₂ (M1 consists of Mg, Ca, Sr, and Ba) At least selected from the group Phosphor or the like are also represented by one element), _Y 3 _Al 5 _O 12 with luminescent color ^{_{greenish: Ce 3+ (YAG), Y}} 2 SiO 5: Ce 3+, Tb 3+, Sr 2 Si 3 O _{8 · 2SrCl 2: Eu, BaMg} 2 Al 16 O 27: Eu 2+, Mn 2+, ZnSiO 4: Mn, Zn 2 SiO 4: Mn, LaPO 4: Tb, SrAl 2 O 4: Eu, SrLa 0.2 Tb 0 _.8 Ga ₃ O ₇ , CaY _0.9 Pr _0.1 Ga ₃ O ₇ , ZnGd _0.8 Ho _0.2 Ga ₃ O ₇ , SrLa _0.6 Tb _0.4 Al ₃ O ₇ , ZnS: Cu, _{Al, (Zn, Cd) S} : Cu, Al, ZnS: Cu, Au, Al, Zn 2 SiO 4: Mn, ZnSiO 4: Mn, ZnS: Ag, Cu, (Zn · Cd) S: Cu, ZnS: Cu , GdOS: Tb, LaOS: Tb, YSiO ₄ : Ce · Tb, ZnGeO ₄ : Mn, GeMgAlO: Tb, SrGaS: Eu ²⁺ , ZnS: Cu · Co, MgO · nB ₂ O ₃ : Ge, Tb, LaOBr: Tb , Tm, La ₂ O ₂ S: Tb, and the like can be used. Further, YVO ₄ : Dy having a white emission color and CaLu _0.5 Dy _0.5 Ga ₃ O ₇ having a yellow emission color can also be used.

When the wavelength of light from the light emitting element is a so-called ultraviolet ray having a wavelength of 400 nm or less, for example, ZnS: Cu, Al, (Zn, Cd) S: Cu, Al, ZnS: Cu, Au, Al, Y ₂ SiO ₅ : Tb, (Zn, Cd) S: Cu, Gd ₂ O ₂ S: Tb, Y ₂ O ₂ S: Tb, Y ₃ Al ₅ O ₁₂ : Ce, (Zn, Cd) S: Ag, ZnS: Ag, Cu , Ga, Cl, Y ₃ Al ₅ O ₁₂ : Tb, Y ₃ (Al, Ga) ₅ O ₁₂ : Tb, Zn ₂ SiO ₄ : Mn, LaPO ₄ : Ce, Tb, Y ₂ O ₃ S: Eu, YVO ₄ : Eu, ZnS: Mn, Y ₂ O ₃ : Eu, ZnS: Ag, ZnS: Ag, Al, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, Sr ₁₀ (PO _{4 ) 6 Cl 2: Eu, (} Ba, Sr, Eu) ( _{g, Mn) Al 10 O 17} , (Ba, Eu) MgAl 10 O 17, ZnO: Zn, Y 2 SiO 5: either Ce or be used in combination of two or more phosphors selected from these it can.

Two or more different types of phosphors can be used in combination.
The second phosphor not only absorbs the light from the light emitting element and emits the third wavelength light, but also absorbs the fluorescence emitted from the first phosphor and emits the third wavelength light. But you can.
A light diffusing material can also be used in combination with the phosphor. As a result, light emission unevenness can be reduced.

(Translucent inorganic connecting layer)
The translucent inorganic coupling layer is made of an inorganic material that binds the phosphor particles to each other. In the prior art, a translucent resin or a low-melting glass is used as a dispersion medium for phosphor particles. However, the translucent inorganic connecting layer of the present invention does not disperse phosphor particles as a dispersion medium. This is because the volume occupied by the translucent inorganic coupling layer in the fluorescent layer is extremely small compared to the phosphor particles. As shown in FIG. 1, the average particle diameter of the phosphor particles 1 is several μm, whereas the film thickness of the translucent inorganic coupling layer 3 covering the phosphor particles 1 is several nm. In other words, the phosphor particles 1 having a size about 1000 times that of the ultrathin linking layer 3 of several nm are connected. Therefore, in order to fill the phosphor particles 1 uniformly and densely, it is preferable to set the film thickness of the translucent inorganic coupling layer 3 to be equal to or less than the average particle diameter of the phosphor particles.
Further, when the phosphor particles 1 are densely filled with the translucent inorganic connecting layer 3, the voids 5 are formed. The light emitted from the light emitting element and the light from the phosphor particles 1 are diffusely reflected in the gap 5, and even if the fluorescent layer is thin, the two lights are sufficiently mixed to obtain the desired light color such as white.

Such a translucent inorganic coupling layer can be formed from an inorganic film-forming liquid. As this inorganic film forming liquid, for example, a liquid for forming a protective film on a semiconductor substrate can be used. This inorganic film forming liquid is applied onto a semiconductor substrate, dried and baked to form a thin film (protective film), which is in close contact with the semiconductor substrate. Such an inorganic film-forming liquid is not particularly limited as long as it has a small viscosity and is evenly mixed with the phosphor particles to form a thin film around the phosphor particles, thereby connecting them to each other. . For example, chemical formula M ¹⁺ (OR ¹ ) _m R ² _l−m (wherein R ¹ is a hydrocarbon group having 1 to 5 carbon atoms, an alkoxyalkyl group or an acyl group, R ² is vinyl, amino, imino, epoxy, acryloyloxy) , Methacryloyloxy, phenyl, mercapto and an organic group containing at least one kind selected from an alkyl group, l is a valence of M, and l and m are integers) An inorganic film-forming liquid composed of a mixture of condensation polymerization products can be used. Here, M can use an element such as Si, Al, Zr, or Ti.

Hydrolysis / condensation polymerization of the alkoxide compound represented by the general formula M ¹⁺ (OR ¹ ) _m R ² _1−m is performed as follows.

The inorganic film forming liquid used in the present invention is a mixture of the hydrolyzed / condensed polymer of the alkoxide compound and has a fluidity comparable to that of water.
In the above, when the metal element M is Si, the following silane compounds can be used. Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4- Epoxycyclohexyl) ethyltrimethoxysilane, γ- (3,4-epoxycyclohexyl) ethyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, phenyltrimethoxysilane, phenyltriacetoxysilane, γ-mercaptopropyltri Methoxysilane, γ-chloropropyltrimethoxysilane, β-cyanoethyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyl Trimethoxysilane, ethyl triethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and the like tetrabutoxysilane.

In addition to the above, it is also possible to use a film forming liquid described in Patent Document 2, such as polyimidesiloxane, as the inorganic film forming liquid (see JP-A-11-110754 and JP-A-9-183948).
Two or more kinds of the various inorganic film forming liquids can be used in combination.

The inorganic film forming liquid and phosphor particles are mixed to obtain a phosphor layer precursor material. This phosphor layer precursor material is sol and has high fluidity. Therefore, a fluorescent layer having an arbitrary shape can be formed using this. By directly applying the phosphor layer precursor material to the light emitting element, the entire light emitting element can be covered with this material. Of course, the material may be filled into the cup-shaped portion where the light emitting element is mounted.
When the phosphor particles contain an alkaline earth metal element and the component reacts with water, the phosphor component or the like may change, and the efficiency of the phosphor may be reduced. When water is contained in the inorganic film forming liquid, such a reaction occurs, and it is necessary to sufficiently remove the water from the inorganic film forming liquid before and / or after the mixing. For example, moisture is removed by any one of heat removal, reduced pressure removal, desiccant removal, or a combination thereof.

This inorganic film forming liquid is cured at a relatively low temperature to fix the phosphor particles. In the case of the silane compound of the example, it is cured at about 200 ° C. Furthermore, most of the organic components are dissociated by the heat treatment at about 400 ° C. In addition, there exists a possibility that a fluorescent substance may modify | denature when it heats exceeding 500 degreeC. Therefore, the heating temperature of the inorganic film forming liquid is preferably 500 ° C. or less.
It is also possible to mold the phosphor layer precursor material by utilizing the fluidity thereof. That is, the phosphor layer precursor material is injected into a mold having the shape of the phosphor layer and molded. The fluorescent layer thus formed is attached to the light emitting element. Thereby, the fluorescent layer can be formed in an arbitrary shape and with high dimensional accuracy.

Next, examples of the present invention will be described.
(First Example)
In this example, a face-up type III-nitride compound semiconductor light emitting device 10 shown in FIG. 2 was used as an optical element. This light emitting element emits blue light.
The specifications of each layer of the light emitting element 10 are as follows.
Layer: Composition p-type layer 15: p-GaN: Mg
Layer 14 including light emitting layer: n-type layer including InGaN layer 13: n-GaN: Si
Buffer layer 12: AlN
Substrate 11: Sapphire Note that the emission wavelength of the light-emitting element can be adjusted by adjusting the composition ratio of the group III element in the layer including the light-emitting layer. In addition, a flip-chip type light emitting element that employs a thick p-type electrode that covers the upper surface of the p-type layer 15 instead of the translucent electrode 16 and the p-electrode 17 can also be used.

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 carbide, zinc oxide, magnesium oxide, manganese oxide, zirconium boride, a group III nitride compound semiconductor single crystal Etc. can be used. Further, the buffer layer is formed by MOCVD using AlN, but the present invention is not limited to this, and GaN, InN, AlGaN, InGaN, AlInGaN, etc. can be used as the material, and molecular beam crystal growth is used as the manufacturing method. A method (MBE method), a halide vapor phase epitaxy method (HVPE method), a sputtering method, an ion plating method, or the like can be used. When a 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 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.
The n-type layer 13 is doped with Si as an n-type impurity, but Ge, Se, Te, C, or the like can also be used as an n-type impurity.
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 light emitting element has a single hetero type, a double hetero type, and a homojunction. It may be of a type.

The layer 14 including the light emitting layer may include a group III nitride compound semiconductor layer having a wide band gap doped with Mg or the like on the p-type layer 15 side. 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 the light-emitting layer. The p-type layer 15 can be AlGaN, InGaN, or InAlGaN, and Zn, Be, Ca, Sr, and Ba can be used as the p-type impurity. After introducing the p-type impurity, the resistance can be lowered by a known method such as electron beam irradiation, heating in a furnace, or plasma irradiation.
In the light emitting device having the above-described configuration, each group III nitride compound semiconductor layer is formed by performing MOCVD under general conditions, a molecular beam crystal growth method (MBE method), a halide vapor phase epitaxy method (HVPE method). ), A sputtering method, an ion plating method, or the like.

The n-electrode 18 is composed of two layers of Al and V. After the p-type layer 15 is formed, the p-type layer 15, the layer 14 including the light emitting layer, and a part of the n-type layer 13 are removed by etching. It is formed by vapor deposition on the exposed n-type layer 13.
The translucent electrode 16 is a thin film containing gold and is stacked on the p-type layer 15. The p-electrode 17 is also made of a material containing gold, and is formed on the translucent electrode 16 by vapor deposition. After forming each layer and each electrode by the above process, the separation process of each chip is performed.

The phosphor layer precursor material was prepared as follows.
First, 70.71 g of γ-glycidoxypropyltrimethoxysilane, 32.32 g of water, and 54.97 g of isopropyl cellosolve are placed in a 200 ml beaker and stirred at room temperature for 1 hour to obtain an inorganic film forming solution.
In this inorganic coating liquid, 61.0 g of YAG phosphor particles (average particle diameter 3 μm) is placed in a ball mill pot and dispersed by a ball mill for 3 hours to obtain a phosphor layer precursor.

  When this phosphor layer precursor material is baked at 400 ° C. for 10 minutes, the inorganic film-forming liquid is cured to form a thin light-transmitting inorganic coupling layer and coat the phosphor particles. As a result, the phosphor particles are connected and fixed to each other to form a phosphor layer.

  Next, when this phosphor layer precursor material is applied to the upper surface (main light emitting surface) of the light emitting device 10 before separation from the wafer and heat-treated under the above conditions (400 ° C., 10 minutes), as shown in FIG. Thus, the fluorescent layer 20 is formed on the upper surface of 10. When the phosphor layer precursor material is applied to the light emitting element 10 separated from the wafer, the phosphor layer precursor material can cover the side surface of the light emitting element due to its fluidity. Moreover, if the light emitting element is immersed in the phosphor layer precursor material, the entire surface of the light emitting element can be covered with the phosphor layer precursor material. If heat treatment is performed in this state, the entire surface of the light-emitting element can be covered with the fluorescent layer (see FIGS. 4 and 5).

An example of the light emitting device 30 in which the light emitting element 10 covered with the fluorescent layer 20 is assembled is shown in FIG. In the light emitting device 30, the light emitting element 10 is fixed to the bottom surface of the cup portion 32 of the mount lead 31. The mount lead 31 and the sub lead 33 are sealed with a shell-type sealing member 37.
According to the light emitting device 30 having such a configuration, the light emitted from the light emitting element 10 excites the phosphor in the phosphor layer 20 and emits fluorescence from the phosphor. For example, when a blue light emitting diode is selected as the light emitting element 10 and combined with a phosphor using blue light as excitation light, white light output light can be obtained as the light emitting device 30.

  FIG. 7 shows a light emitting device 40 according to another embodiment. In addition, the same code | symbol is attached | subjected to the element same as FIG. 6, and the description is abbreviate | omitted. In this light emitting device 40, instead of laminating the fluorescent layer 20 on the surface of the light emitting element 10, a fluorescent layer precursor material was filled into the cup portion 32 and solidified. Thereby, the fluorescent layer 41 which entirely surrounds the light emitting element 10 is obtained. In the fluorescent layer 41 of this embodiment, since the fluorescent material is densely packed, the light transmittance as the fluorescent layer may be lowered depending on the type of the fluorescent material. In this case, it is preferable to mix translucent filler particles with the phosphor particles in order to ensure a light passage.

(Second embodiment)
In this embodiment, the phosphor layer is molded using the phosphor layer precursor material.
As the fluorescent layer precursor material, an auxiliary agent such as a thickener is added to the material used in the previous embodiment to obtain a viscosity suitable for molding.
In the light emitting device 50 shown in FIG. 8, a press-molded cup-shaped fluorescent layer 51 is placed on the light emitting element 10. In addition, the same code | symbol is attached | subjected to the element same as FIG. 6, and the description is abbreviate | omitted. A plan view of the fluorescent layer 51 is shown in FIG. As shown in FIG. 9, notches 52 and 53 for releasing the bonding wires are formed in the molded fluorescent layer 51 of this embodiment.

  FIG. 10 shows another example of the light emitting device 60. In the light emitting device 60, a flip chip type light emitting element 61 is used. The light emitting element 61 is connected to lead frames 65 and 66 via bumps 62 and 63. The light emitting element 61 is covered with a fluorescent layer 68 press-molded into a mass. The flip-chip type light-emitting element is a face-up type shown in FIG. 2, in which a thick p-electrode covering the surface of the p-type layer is laminated instead of the translucent electrode 16 and the pad-type p-electrode 17. It is a configuration.

  As an example of the molded fluorescent layer, the one shown in FIG. 11 can be adopted. The fluorescent layer 71 shown in FIG. 11A is a cannonball type. The fluorescent layer 72 shown in FIG. 11B has a reflective lens shape.

  In the light-emitting device 80 shown in FIG. 12, the light-emitting element 10 is mounted on a phosphor layer 81 that is molded as a base. In the figure, reference numeral 83 denotes a reflection case, and reference numerals 84 and 85 denote leads. According to the light emitting device 80, the light emitted from the light emitting element 10 is reflected by the reflection case 83 and enters the fluorescent layer 81 as a base to excite the phosphor.

(Third embodiment)
13 and 14 show a light emitting device 160 of another embodiment. In addition, the same code | symbol is attached | subjected to the element same as FIG. 10, and the description is abbreviate | omitted.
In this embodiment, a light-transmitting material 169 is filled between the molded mass type fluorescent layer 168 and the flip chip type light emitting element 61.
The phosphor contained in the phosphor layer 168 is not particularly limited, but YAG phosphors and BOS phosphors are preferable. As the light emitting element 61 for these phosphors, one or more of those emitting ultraviolet light, red light, blue light, yellow light and green light can be used.
In the case of phosphors with high light conversion efficiency such as YAG phosphors and capable of sufficient light wavelength conversion, fillers (SiO ₂ , Al ₂ O ₃ , TiO _2, etc.) are included in the phosphor layer precursor material It is preferable to do. This is because the moldability of the fluorescent layer 168 is improved by introducing the filler. Moreover, even if the filler is introduced, the light conversion efficiency of the phosphor is high, so that the entire phosphor layer 168 has sufficient light conversion ability.

The thickness of the fluorescent layer 168 is arbitrarily selected according to the color tone required for the light emitting device. The fluorescent layer 168 does not need to be formed in the same thickness in all portions, and the thickness can be changed in accordance with the light emission intensity from the light emitting element 61.
It is assumed that the lower edge of the fluorescent layer 168 is positioned at least below the light emitting layer of the light emitting element 61. Preferably, as shown in FIG. 13, the lower edge of the fluorescent layer 168 is brought into contact with the surface of the base on which the light emitting element 61 is placed. This ensures that the light emitted from the side surface of the light emitting element 61 passes through the fluorescent layer 168 and is wavelength-converted.
Between the fluorescent layer 168 and the light emitting element 61, as shown in FIG. 14, the translucent inorganic material 169 is filled substantially without a gap. By filling the light-transmitting inorganic material 169, the air layer is eliminated, and the light-transmitting inorganic material 169 having a refractive index higher than that of air and vacuum is adjacent to the light-emitting element, so that the light extraction efficiency from the light-emitting element is increased. Will improve. The heat generated from the light-emitting element is transmitted to the sealing layer 37 disposed outside the light-transmitting inorganic material 169 and the fluorescent layer 168 adjacent to the light-emitting element. In addition, the presence of the light-transmitting inorganic material 169 allows more heat from the light-emitting element to be transmitted than when it does not exist, and the heat of the light-emitting element is reduced. Functional degradation can be reduced. Further, by filling the translucent inorganic material 169, in the step of sealing the sealing agent 37, the mechanical strength of the fluorescent layer is improved and the handling becomes easy.
As the translucent inorganic material, it is preferable to use an inorganic film forming liquid that constitutes the fluorescent layer precursor material of the fluorescent layer 168 from the viewpoint of improving adhesiveness.

  The light emitting device 161 of this embodiment is formed as follows. That is, the flip chip type light emitting element 61 is fixed to the lead frames 65 and 66 by the bumps 62 and 63. On the other hand, the fluorescent layer 168 is formed by molding. Then, the mass-type fluorescent layer 168 is filled with a fluid inorganic film forming liquid (with translucency), and is put on the light emitting element 61. As a result, the inorganic film forming liquid is filled between the molded fluorescent layer 168 and the light emitting element 61. Then, when heated, the inorganic film forming liquid is cured, and the light emitting element 61 and the fluorescent layer 168 are firmly bonded.

  The present invention is not limited to the description of the embodiments and examples of the invention described above. Various modifications may be 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.

It is a figure which shows typically the structure of the fluorescent layer of this invention. It is sectional drawing which shows the structure of the light emitting element used in the Example of this invention. It is sectional drawing which shows the light emitting element provided with the fluorescent layer of the Example. It is sectional drawing which shows the light emitting element provided with the fluorescent layer of another Example. It is sectional drawing which shows the light emitting element provided with the fluorescent layer of another Example. It is sectional drawing which shows the structure of the light-emitting device provided with the light emitting element shown in FIG. It is sectional drawing which shows the light-emitting device of another Example. It is sectional drawing which shows the light-emitting device of another Example. It is a top view of the fluorescent layer molded for the face-up type light emitting device. It is sectional drawing which shows the structure of the light-emitting device of another Example. It is a side view which shows the fluorescent layer shape-molded for flip chip type light emitting elements. It is sectional drawing which shows the structure of the light-emitting device of another Example. It is a top view which shows the structure of the light-emitting device of another Example. It is the sectional view on the AA line in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Phosphor particle 3 Translucent inorganic coupling layer 5 Space 10, 61 Light emitting element 20, 41, 51, 68, 71, 72, 73, 81, 168 Fluorescent layer 30, 40, 50, 60, 80, 161 Light emission device

Claims (8)

In a light emitting device comprising: a light emitting element; and a fluorescent layer that excites and fluoresces light emitted from the light emitting element.
The fluorescent layer is Ri Do from the phosphor particles and the light-transmitting inorganic coupling layer, the phosphor particles are connected through the light-transmitting inorganic coupling layer, Ru space is formed between the phosphor particles A light emitting device characterized by that. 2. The translucent inorganic coupling layer covers the phosphor particles, and the translucent inorganic coupling layer has a film thickness equal to or less than an average particle diameter of the phosphor particles. The light emitting device according to 1. The translucent inorganic coupling layer has a chemical formula M ¹⁺ (OR ¹ ) _m R ² _l−m (where M is an element including any one of Si, Al, Zr, and Ti, R ¹ has 1 to ¹ carbon atoms) 5 hydrocarbon group, alkoxyalkyl group or acyl group, R ² is an organic group containing at least one selected from vinyl, amino, imino, epoxy, acryloyloxy, methacryloyloxy, phenyl, mercapto and alkyl groups, l is M And a mixture of a hydrolyzate of the alkoxide compound represented by the formula (1) and (2) and a hydrolyzed / condensed polymer: The light emitting device according to any one of the above. The inorganic film-forming liquid has a chemical formula M ¹ + (OR ¹ ) _m R ² _l−m (where M is an element including any one of Si, Al, Zr, and Ti, and R ¹ has 1 to 5 carbon atoms) A hydrocarbon group, an alkoxyalkyl group or an acyl group; R ² is an organic group containing at least one selected from vinyl, amino, imino, epoxy, acryloyloxy, methacryloyloxy, phenyl, mercapto and alkyl groups; the number, and an inorganic film forming solution consisting of a mixture of l and m is hydrolyzate of an alkoxide compound represented by an integer) and hydrolysis-condensation polymerization product, a fluorescent layer precursor by mixing the phosphor particles Create material,
The phosphor layer precursor material is heat-treated, the inorganic film forming liquid is cured to form a transparent inorganic coupling layer, phosphor particles are coupled through the transparent inorganic coupling layer, and the fluorescence Forming spaces between body particles,
A method for producing a fluorescent layer for a light-emitting device. The method for manufacturing a fluorescent layer according to claim 4, wherein the heat treatment temperature is 500 ° C. or less. The method for producing a fluorescent layer according to claim 4, wherein the fluorescent layer precursor material is applied to a light emitting element. The method for producing a fluorescent layer according to claim 4 , wherein the fluorescent layer is molded by the fluorescent layer precursor material. The manufacturing method of the light emitting device containing the manufacturing method of the fluorescent layer in any one of Claims 4-7 .

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