JP5368913B2 - Light emitting device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device having a light-emitting ceramic disposed on an upper surface of an LED (light-emitting diode) and having a small angle-dependency of the light-emitting chromaticity. <P>SOLUTION: A size in a principal plane direction of a color conversion member 210 mounted on the upper surface of a light-emitting element 230 is smaller than that of the upper surface of the light-emitting element 230. A light diffusion member 240 is put together with an outer circumference end surface of the color conversion member 210 and covers an area on which the color conversion member 210 of the light-emitting area on the upper surface of the light-emitting element 230 is not disposed. This guides a wave in the color conversion member, and light emitted from the end surface and having many fluorescent component is mixed with excitation light directly entering from the light-emitting element in the light diffusion member to increase the excitation light component. Therefore, the difference of the light-emitting chromaticity between the light emitted from the end surface direction and the light emitted from the upper surface direction can be decreased. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a light emitting device that performs color conversion of light emitted from a light emitting element (LED) using a color conversion member, and more particularly to a light emitting device that uses light emitting ceramics.

  A light emitting device in which a nitride semiconductor light emitting diode (LED) and a phosphor layer in which a phosphor powder is dispersed in a resin member is combined is widely used as a light source for an indicator or a backlight. Further, in recent years, the output has been increased, and the adoption as a light source for general lighting and headlamps of automobiles has begun.

  In the future, higher output of LEDs is desired, but there are problems to be solved for this purpose. One of the problems is temperature quenching, which is a phenomenon in which the emission intensity decreases as the temperature of the phosphor increases. In order to increase the output of the LED, it is necessary to increase the drive current. However, as the drive current increases, a large amount of heat is generated in the LED, which heats the phosphor and reduces the emission intensity of the phosphor. As a result, there arises a problem that the output of the LED cannot be increased.

  In order to solve this, Patent Document 1 proposes a light-emitting device in which a light-emitting ceramic made of polycrystalline phosphor is disposed instead of a resin in which phosphor powder is dispersed. Luminescent ceramics are known to be less temperature sensitive than phosphor powders. Patent Documents 2 and 3 disclose methods for producing luminescent ceramics.

JP 2006-5367 A Japanese Patent Laid-Open No. 5-294722 Japanese Patent No. 3906352

  However, as described in Patent Document 1, when a luminescent ceramic is used instead of the resin layer in which the phosphor powder is dispersed, a large amount of fluorescent components are emitted from the end face because light propagates through the luminescent ceramic. And the end face have different emission chromaticities. For this reason, there exists a problem that the angle dependence of light emission chromaticity will arise as a light-emitting device.

More specifically, the luminescent ceramic is a polycrystal that does not include a binding member such as a resin therein, and the refractive index is substantially continuous even at the grain boundary. The refractive index of luminescent ceramics is generally higher than that of air . For this reason, when a thin plate of luminescent ceramics is disposed on the upper surface of the LED chip, a part of the excitation light that has entered the luminescent ceramics from the LED is guided in the luminescent ceramics. The guided light is emitted from the end face of the luminescent ceramic. The light emitted from the end surface has a longer optical path length in the luminescent ceramic than the light emitted from the upper surface, so that the fluorescent component increases. As a result, the emission color observed from the upper surface direction of the light emitting device and the emission chromaticity observed from the oblique direction are greatly different, which becomes a problem when the light emitting device is used as a light source.

  An object of the present invention is to provide a light emitting device in which a light emitting ceramic is disposed on an upper surface of an LED, and has a small angle dependency of light emission chromaticity.

In order to achieve the above object, the present invention provides the following light emitting device. That is, a light emitting element is mounted on the upper surface of the light emitting element, a light-emitting device having a color conversion member for converting the light emission color of the light emitting element, the color conversion member, the upper surface of the size of the main plane direction the light emitting element Is smaller than the size of A light diffusing member is bonded to the outer peripheral end surface of the color conversion member, and the light diffusing member covers a region of the light emitting region on the upper surface of the light emitting element where the color converting member is not disposed. As a result, light with a large amount of fluorescent component that is guided through the color conversion member and emitted from the end face enters the light diffusing member, and the excitation light and the light diffusing member directly enter the lower surface of the light diffusing member from the light emitting element. Mixed inside. The excitation light component of the light emitted from the end surface direction of the luminescent ceramic can be increased, and the difference in emission chromaticity from the light emitted from the upper surface direction can be reduced.

  The conversion member is preferably made of a crystal. For example, the color conversion member is made of a phosphor crystal that emits fluorescence using light emitted from the light emitting element as excitation light.

  The light diffusing member has, for example, a structure in which particles are dispersed in a resin that is transparent to light emitted from the light emitting element and light converted by the color conversion member. The particle size of the particles is preferably 500 nm or more and 10 μm or less.

  Alternatively, the light diffusing member can be made of a crystal body including an impurity phase having a crystal structure different from that of the color conversion member.

  For example, the crystal of the color conversion member includes the emission center ion in the crystal structure, and the crystal of the light diffusion member does not include the emission center ion.

  According to another aspect of the present invention, the following method for manufacturing a light emitting device is provided. That is, a method of manufacturing a light-emitting device having a light-emitting element, a color conversion member mounted on the upper surface of the light-emitting element, and a light diffusion member bonded to an outer peripheral end surface of the color conversion member, A light transmissive ceramic made of a crystalline material is prepared, and a light diffusing ceramic made of a material containing an impurity phase that causes light scattering is added to a crystal having the same crystal structure as a phosphor as a light diffusing member. This is a method in which both are prepared by firing in a state where the light diffusing ceramic is in contact with the outer peripheral end face of the light transmissive ceramic.

  According to the present invention, the light with a large amount of fluorescent component that is guided through the color conversion member and emitted from the end face is incident on the light diffusion member, and the excitation light and light are directly incident on the lower surface of the light diffusion member from the light emitting element. Since they are mixed inside the diffusing member, the excitation light component of the light emitted from the end face direction of the color conversion member can be increased. As a result, it is possible to provide a light-emitting device that has a small angle dependency of light emission chromaticity and that can increase output.

Sectional drawing of the light-emitting device of this embodiment. The top view of the light-emitting device of this embodiment. The top view which shows the structure which made the corner | angular part of the diffuser member of the light-emitting device of this embodiment curved surface. Sectional drawing of the LED chip which can be used with the light-emitting device of this embodiment. Sectional drawing of the LED chip which can be used with the light-emitting device of this embodiment. Sectional drawing of the light-emitting device of a comparative example.

  An embodiment of the present invention will be described.

  The light-emitting device of the present invention uses, as a color conversion member, a light-emitting ceramic that is a crystalline phosphor that does not include a binding member such as a resin. The luminescent ceramic is made into a thin plate and mounted on the upper surface (light emitting surface) of the LED chip. At this time, the size of the luminescent ceramic is made smaller than the upper surface of the LED chip, and the luminescent ceramic is not disposed on the peripheral portion of the upper surface of the LED chip. A light diffuser is disposed so as to cover the peripheral edge of the upper surface of the LED chip from the end face (outer face) of the luminescent ceramic. Thereby, the fluorescence emitted from the end face of the luminescent ceramic is incident on the inside of the light diffuser, and mixed and diffused with the excitation light incident on the light diffuser from the periphery of the upper surface of the LED chip. .

  The structure of the light emitting device of this embodiment will be described with reference to FIGS. 1 and 2 are a cross-sectional view and a top view of the light-emitting device. The LED chip 230 is fixed on the substrate 220, and the light emitting ceramic 210 is mounted on the upper surface of the LED chip 230. As the LED chip 230, one that emits light substantially only from the upper surface of the chip is used.

  The light-emitting ceramics 210 are thin plate-shaped, and the size in the main plane direction is smaller than the upper surface of the LED chip 230 and is arranged at the center of the LED chip 230. For this reason, there is a region where the light emitting ceramic 210 is not disposed in the peripheral portion of the upper surface of the LED chip 230.

  An annular diffuser member 240 is disposed on the peripheral edge of the upper surface of the LED chip 230. The inner peripheral surface of the annular diffuser member 240 is joined to the outer peripheral end surface of the luminescent ceramic 210. The thickness of the diffuser member 240 is preferably equal to or greater than the thickness of the luminescent ceramic 210. The position of the outer surface of the diffuser 240 coincides with the position of the outer surface of the LED chip 230 as shown in FIG. 1, or the outer surface of the diffuser 240 is more outward than the outer surface of the LED chip 230. It is desirable to overhang.

  With such a structure, the light emitted from the upper surface of the LED chip 230 enters the luminescent ceramic 210 and the diffuser member 240. The luminescent ceramic 210 absorbs a part of the light of the LED chip 230 and is excited to emit fluorescence. From the upper surface of the light emitting ceramic 210, mixed light of light emitted from the LED chip 230 and transmitted through the light emitting ceramic 210 and fluorescence emitted from the light emitting ceramic 210 is emitted. Part of the light emitted from the LED chip 230 is multiply reflected by the upper and lower surfaces of the luminescent ceramic 210 to excite the luminescent ceramic 210 while propagating through the luminescent ceramic 210. Compared with the excitation light transmitted in the normal direction, the optical path length passing through the inside of the luminescent ceramic 210 is long, and a lot of fluorescence is generated. For this reason, the light emitted from the end surface 210a of the luminescent ceramic 210 has more fluorescent components than the upper surface, and has different chromaticity from the emitted light from the upper surface of the phosphor ceramic 210. In the configuration of the present embodiment, in the diffuser member 240, the excitation light from the LED chip 230 is mixed with the light emitted from the end face of the luminescent ceramic to adjust the chromaticity.

  That is, light (fluorescent component and excitation light component) emitted from the end surface 210a of the luminescent ceramic 210 enters from the inner surface of the diffuser member 240 in contact with the end surface of the luminescent ceramic 210a and is scattered inside. On the other hand, light from the upper surface of the LED chip 230 is directly incident from the lower surface of the diffuser member 240, and is mixed with light from the end surface 210a of the light emitting ceramic 210. Thereby, excitation light is mixed with the light emitted from the end face of the luminescent ceramic 210, and the chromaticity is adjusted. The fluorescence and excitation light mixed and scattered inside the diffuser member 240 are emitted from the upper and outer surfaces of the diffuser. As a result, light whose ratio between the fluorescent component and the excitation light component is adjusted is emitted from the outer surface of the diffusing member 240, so that the chromaticity difference from the emitted light is small from the upper surface of the luminescent ceramic 210, and the chromaticity is reduced. Angle dependency can be reduced.

  By controlling the light diffusion characteristics and width of the diffuser member, the thickness of the luminescent ceramic 210 and the concentration of the luminescent center ion, it is possible to make the luminescence chromaticity of the luminescent mix and the diffuser the same, resulting in temperature quenching. Although the light emitting device performs color conversion using a difficult light emitting ceramic, the angle dependency of the light emission chromaticity can be reduced.

The luminescent ceramic 210 is made of a ceramic crystal body that does not substantially contain 5 wt% or less of a binding member such as a resin, and has a thin plate shape with a predetermined thickness. The crystal of the luminescent ceramic 210 is generally a polycrystal having grain boundaries, but is not limited to a polycrystal and may be a single crystal as a whole. For example, phosphors having a garnet structure typified by YAG (Y ₂ Al ₅ O ₁₂ ), silicate phosphors, aluminate phosphors, scandinate phosphors, oxynitride phosphors represented by sialon, nitride silicon Polycrystalline or single crystal of one kind of phosphor selected from nitride phosphor, halosilicate phosphor, haloborate phosphor, sulfide phosphor represented by nitride and nitride aluminum silicon nitride Alternatively, a polycrystal of a mixture of two or more kinds of phosphors can be used. In particular, a YAG phosphor doped with a predetermined impurity (emission center ion: Ce, for example) has high luminous efficiency and is excited by blue light to emit yellow fluorescence. For this reason, since white light can be obtained by the mixed light of blue excitation light and yellow fluorescence, it is practically advantageous.

  In addition, a light-emitting ceramic with high translucency is desirable because light loss in the light-emitting ceramic can be avoided and high luminance of the light-emitting device can be achieved. However, this does not preclude imparting appropriate light diffusion characteristics by introducing pores or impurity phases into the luminescent ceramic.

  Furthermore, it is also possible to use a surface of a luminescent ceramic provided with a predetermined fine structure by molding polishing, etching or the like in order to improve the light extraction efficiency and to have an arbitrary light distribution characteristic.

  As the diffuser member 240, a light diffusing resin or a light diffusing ceramic can be used.

  As the light diffusion resin, for example, a resin in which a diffusion material is mixed is used. A configuration in which the scattering material causes more forward scattering than back scattering is preferable because light can be efficiently extracted from the diffuser member 240.

  As the resin, silicone, epoxy, silicon epoxy, fluorine, and the like can be used, and a silicone resin is particularly preferable. As the diffusing material, it is preferable to use fine particles or fillers of inorganic materials such as aluminum oxide, titanium dioxide, zirconium oxide, and magnesium oxide.

  The diffusion material preferably has a particle size of 10 nm or more and 20 μm or less. In particular, a particle diameter of 500 nm or more and 10 μm or less is preferable because a lot of forward scattering occurs. This is because when excitation light or fluorescence is visible light, if the particle size of the diffusing material is 500 nm or more, the forward scattering component of Mie scattering increases, and if it is larger than 10 μm, the light is reflected or refracted by the particles. This is because the forward scattering component is reduced.

  The mixing ratio of the resin and the diffusing material can be set to a predetermined ratio. For example, a rotary defoaming device can be used in the step of mixing the uncured resin and the diffusing material into a paste. Considering the degree of diffusion and ease of molding, it is desirable to use a light diffusing resin containing 30 to 70 wt% of a diffusing material. In addition to the diffusion material, it is also possible to mix a thickening material such as fumed silica having a particle size of 10 nm or less in order to adjust the viscosity of the paste.

  As the diffuser member 240, light diffusing ceramics can also be used. The light diffusing ceramic is a ceramic having diffusion characteristics. For example, it is possible to use a ceramic having the same crystal structure as that of the luminescent ceramic and not including a luminescent center ion and including an impurity phase having a crystalline structure. is there. Since the impurity phase causes light scattering properties, even ceramics having the same crystal structure have diffusion characteristics.

  Further, as the shape of the diffuser member 240, it is preferable that the corner portion has a curved surface shape with a predetermined radius of curvature as shown in FIG. By making the corners into a curved shape, the distance between the outer surface of the diffuser member 240 and the end face of the luminescent ceramic 210 can be kept substantially constant even at the corners, thus reducing the emission chromaticity distribution in the outer circumferential direction. be able to. However, it is preferable that the upper surface of the LED chip 230 is not exposed to the outside of the diffuser member 240 even when the corners of the diffuser member 240 are curved. This is to prevent light emitted from the LED chip 230 from being directly emitted from the outside of the diffuser member 240. Therefore, for example, the diffuser member 240 is formed so as to protrude outward from the outer surface of the LED chip 230, or a light shielding member is mounted on the upper surface region of the LED chip 230 located outside the diffuser member 240. It is possible.

  In the structure shown in FIG. 1, the diffuser member 240 is not formed on the upper surface of the luminescent ceramic 210, but the present invention may have a structure in which the upper surface of the luminescent ceramic 210 is covered with the diffuser member 240. Is possible.

  As the LED chip 230, for example, one having an emission wavelength in the visible light region is used. Specific examples include gallium nitride compound semiconductors, zinc oxide compound semiconductors, zinc selenide compound semiconductors, and the like. In particular, in the case of a light emitting device that emits white light, an LED chip having an emission wavelength in the blue light range of 440 to 470 nm is suitable.

  The structure of the LED chip 230 is desirably a chip structure that allows light to be extracted substantially only from the top surface of the chip in order to make excitation light efficiently enter the luminescent ceramic 210 and the diffuser member 240.

  As an example of such a chip structure, an LED chip having a structure as shown in FIGS. 4 and 5 can be used. The LED chip in FIG. 4 includes a p-type electrode layer 340, a p-type semiconductor layer 330, an active layer 320, and an n-type semiconductor layer 310, which are sequentially stacked from the substrate 230 side. This is a flip chip in which a part of is cut out and an n-type electrode 350 is arranged. The LED chip in FIG. 5 includes a support substrate 460, a p-type electrode layer 450, a p-type semiconductor layer 440, an active layer 430, and an n-type semiconductor layer 420, which are sequentially stacked from the substrate 230 side. In this structure, an n-type electrode 410 is arranged on a part of the top.

  4 and FIG. 5 has a thin thickness of several μm because the growth substrate is removed after the epitaxial layers 310 to 330 and 420 to 440 are grown. Furthermore, electrodes 340 and 450 serving as reflective surfaces are disposed under the active layer, and light extraction structures are provided in the n-type semiconductor layers 310 and 420 located on the upper surface of the chip. For this reason, it is possible to extract light substantially only from the upper surface of the chip.

  Next, a method for manufacturing the light emitting device of this embodiment will be described.

  First, a luminescent ceramic is manufactured. Luminescent ceramics can be manufactured using a widely known method for manufacturing translucent ceramics. The manufacturing method of translucent ceramics is described in Patent Documents 2 and 3 described above, for example.

  As an example, the case of producing a luminescent ceramic made of YAG: Ce polycrystal doped with Ce will be described. It is manufactured through a starting material mixing step, a molding step, a firing step, and a processing step.

  As starting materials, oxides of constituent elements of YAG: Ce phosphors such as yttrium oxide, cerium oxide and alumina, carbonates, nitrates, sulfates and the like that become oxides after firing are used. The particle size of the starting material is preferably a submicron size. These raw materials are weighed so as to have a stoichiometric ratio. At this time, a compound such as calcium or silicon can be added for the purpose of improving the transmittance of the sintered ceramic.

  The weighed raw materials are sufficiently dispersed and mixed by a wet ball mill using water or an organic solvent. Next, the mixture is formed into a predetermined shape. As the molding method, a uniaxial pressing method, a cold isostatic pressing method, a slip casting method, an injection molding method, or the like can be used. The obtained molded body is fired at 1600-1800 ° C. Thereby, translucent YAG ceramics can be obtained. Finally, the ceramic is cut into a desired size and polished to obtain a YAG luminescent ceramic. As an example, the luminescent ceramic 210 having a thickness of several tens to several hundreds of μm is processed. The size in the main plane direction is processed to be smaller than the upper surface of the LED chip 230.

  The diffuser member 240 is joined to the end face 210a of the obtained luminescent ceramic 210. First, a case where a light diffusion resin is used as the diffuser member 240 will be described. When forming the diffuser member 240 made of light diffusing resin, a step of forming an uncured light diffusing resin material (paste) on the end face 210a of the luminescent ceramic 210, and a step of curing the light diffusing resin material by heating I do. As a result, the diffuser member 240 made of the light diffusing resin is molded into a predetermined shape and joined to the end surface 210a of the luminescent ceramic 210.

  As the light diffusing resin material (paste), an uncured predetermined resin and a diffusing material having a predetermined particle size and amount are prepared, and a paste in which these are mixed is prepared. The paste is formed in the shape of a predetermined diffuser member 240 around the luminescent ceramic 210. As a method for forming the paste into the shape of the diffuser member 240, a printing method, a mold method, or the like can be used. In the case of the printing method, first, the luminescent ceramic 210 is fixed to an appropriate substrate, and a mask having an opening is put around the substrate. The paste is formed by filling the paste around the luminescent ceramic 210 by placing the paste on the mask and printing with a squeegee. Next, after removing the mask, a predetermined curing method, for example, a heat curing step is performed to cure the paste.

  In the case of the mold method, a metal or rubber mold is provided around the luminescent ceramic, and the paste is molded by pouring the paste there. Next, it is cured by a predetermined curing method, for example, heating, without removing the mold. Remove the mold after curing. It is also possible to prepare the mold first, fill it with a paste made of a resin and a diffusing material, and then put the luminescent ceramic 210 into the mold and cure it.

  Further, the present invention may have a structure in which the upper surface of the luminescent ceramic 210 is covered with the diffuser member 240. Such a structure can also be formed by a printing method or a formwork method.

  Next, a manufacturing method in the case where a light diffusing ceramic is used as the diffuser member 240 will be described. As an example, a case where a YAG ceramic is used as the luminescent ceramic 210 will be described. In this case, the light diffusing ceramic does not contain the luminescent center ion, and the material is charged with a composition shifted from the stoichiometric ratio of YAG by several ppm to several percent in molar ratio. It is. By making the composition slightly deviated from the stoichiometric ratio of YAG, an impurity phase having a refractive index different from that of YAG appears in the ceramic, so that the ceramic exhibits diffusion characteristics and a light diffusing ceramic is obtained.

  The obtained light diffusion ceramics is processed into the shape of the diffuser member 240. After sufficiently bonding the bonding surface (end surface 210a) of the diffusing ceramic member 210 and the diffuser member 240 made of light diffusing ceramics, they are brought into contact with each other and fired again at 1600-1800 ° C. as they are. Thereby, it is possible to join the luminescent ceramic 210 and the diffuser member 240 made of the light diffusing ceramic.

  Next, a substrate 220 on which a wiring pattern is formed in advance is prepared, and a separately manufactured LED chip 230 is bonded onto the substrate 220. The electrode of the LED chip 230 is connected to the wiring on the substrate 220. The light emitting ceramics 210 with the diffuser member 240 manufactured in the above-described process is mounted on the upper surface of the LED chip 230 and bonded. The luminescent ceramic 210 with the diffuser member 240 is preferably directly bonded to the LED chip 230. An adhesive, resin, low-melting glass, or the like can be used for bonding. Thus, the light emitting device of this embodiment is completed.

  The light emitting device of this embodiment can be used for all LED light emitting devices that require high output, and is particularly suitable as a light source for headlamps and a light source for illumination.

In the above-described embodiment, an example in which a light emitting ceramic that is a polycrystalline phosphor of a phosphor is used as the color conversion member has been described. However, the phenomenon in which light is guided inside the color conversion member is However, the present invention is not limited to this, and occurs when a flat member having a refractive index of, for example, 1.5 or more is used. In particular, it occurs in a polycrystal or single crystal having high transparency and a refractive index substantially continuous inside. Therefore, the configuration of the present invention is not limited to the case where a phosphor luminescent ceramic is used as the color conversion member, but other color conversion members in which light is guided, for example, color conversion members using harmonics ( It can also be applied to SHG elements.

  In the above-described embodiment, when both the color conversion member (the light emitting ceramic 210) and the light diffusing member 240 use a crystal, that is, when the light diffusing ceramic is used as the light diffusing member 240, the same crystal structure as the light emitting semix 210 is used. However, the present invention is not limited to this, and may have a crystal structure different from that of the luminescent ceramic 210. However, it is preferable that the luminescent ceramic 210 and the light diffusing member 240 have the same crystal structure because joining is easy. When the luminescent ceramic 210 and the light diffusing member 240 have different crystal structures, cracks due to thermal expansion and defects at the interface may occur. Therefore, it is preferable to devise a joining method that does not cause the crack.

  Examples of the present invention will be described below.

Example 1
The light emitting device having the structure shown in FIGS. 1 and 2 was manufactured as follows.

  YAG ceramics with a cerium concentration of 0.5mo1% manufactured by Kamishima Chemical Industry was molded to a length of 0.8mm on one side and a thickness of 0.1mm to obtain luminescent ceramics 210. This was fixed on an aluminum substrate. Next, the YAG ceramics is covered with a metal mask with a thickness of 0.1 mm with an opening with a width of 1.0 mm, and the opening is filled with a silicone resin paste containing 60% by weight of titanium oxide particles with a particle size of 600 nm by a printing method. The member 240 was molded.

  After removing the mask, the paste was cured by heating at 150 ° C. for 2 hours. As a result, a luminescent ceramic 210 having a diffuser member 240 having a width of 0.1 mm and a thickness of 0.1 mm joined to the end face 210a was produced.

  Next, an alumina substrate 220 on which a predetermined wiring pattern was formed was prepared. On the alumina substrate 220, an LED chip 210 whose upper side is 1.0 mm square is bonded in advance with gold ball bumps.

  The light emitting ceramics 210 with the diffuser member 240 was adhered to the upper surface of the LED chip 210 with a silicone resin, and heat cured at 150 ° C. for 2 hours. As a result, a light emitting device having the structure of FIG. 1 was obtained.

  The angle dependency of emission chromaticity of the obtained light emitting device was evaluated. In the evaluation method, the LED chip 230 of the light emitting device was caused to emit light, and the light emission chromaticity was measured from the direction directly above the light emitting ceramics 210 with the diffuser member 240 (normal direction) and from the direction inclined 45 degrees from the direction directly above. For the measurement, a measuring device ProMetric manufactured by Radiant Imagmg was used. The value of xy space of CIE1931 was used for evaluation. The measurement results are shown in Table 1 below. The LED drive current at the time of measurement was 700 mA.

(Example 2)
The diffuser member 240 was formed using a silicone resin paste containing 30 wt% of titanium oxide particles. Other than that, a light-emitting device was manufactured and evaluated using the same materials and processes as in Example 1. Table 1 shows the measurement results.

(Example 3)
The width of the diffuser member 2 was set to 0.05 mm. Other than that, a light emitting device was manufactured and evaluated using the same materials and processes as in Example 1. Table 1 shows the measurement results.

（評価）
表1の結果の通り、実施例１〜３の発光装置の色度差は、比較例の色度差よりも小さく、拡散体部材240を配置することによって発光色度の角度依存性を小さくできることが確認できた。 (Comparative example)
As shown in FIG. 6, the luminescent ceramic 210 was mounted on the entire upper surface of the LED chip 230 without a diffuser member. Other than that, a light emitting device was manufactured and evaluated using the same materials and processes as in Example 1. Table 1 shows the measurement results.

(Evaluation)
As shown in Table 1, the chromaticity difference of the light emitting devices of Examples 1 to 3 is smaller than the chromaticity difference of the comparative example, and the angular dependence of the luminescent chromaticity can be reduced by arranging the diffuser member 240. Was confirmed.

220 ... substrate 210 ... luminescent ceramics 230 ... LED chip 240 ... diffuser member 310 ... n-type semiconductor layer 320 ... active layer 330 ... p-type semiconductor layer 340 ... p-type electrode layer 350 ... n-type Electrode, 410 ... n-type electrode, 420 ... n-type semiconductor layer, 430 ... active layer, 440 ... p-type semiconductor layer, 450 ... p-type electrode, 460 ... support substrate.

Claims (7)

A light emitting element that emits light only from the upper surface, and a color conversion member that is mounted on the upper surface of the light emitting element and is made of a phosphor crystal that emits fluorescence using the light emitted from the light emitting element as excitation light ,
The color conversion member has a size in the main plane direction smaller than the size of the upper surface of the light emitting element,
An annular light diffusion member is joined to the outer peripheral end surface of the color conversion member,
The annular light diffusing member has a thickness equal to or greater than the thickness of the color conversion member, an inner peripheral surface is in contact with an outer peripheral end surface of the color conversion member, and an outer peripheral surface is an outer surface of the light emitting element. It corresponds to the position, or protrudes outside the outer surface of the light emitting element , the lower surface is in contact with the region where the color conversion member of the light emitting region of the upper surface of the light emitting element is not disposed, and covers the region ,
An inner peripheral surface of the annular light diffusing member is in contact with an outer peripheral end surface of the color conversion member, and constitutes a first incident surface on which light emitted from the color conversion member is incident on the light diffusing member, The lower surface of the annular light diffusing member constitutes a second incident surface on which light emitted from the upper surface of the light emitting element is incident on the light diffusing member, and from the color conversion member incident from the first incident surface. The light is mixed inside the light diffusing member with the excitation light from the light emitting element incident from the second incident surface, and is emitted from the upper surface and the outer peripheral surface of the light diffusing member,
An upper surface of the color conversion member is not covered with the light diffusion member . The light-emitting device according to claim 1, wherein a corner portion of an outer surface of the light diffusing member has a curved shape . 3. The light emitting device according to claim 2, wherein a distance between the outer peripheral surface of the light diffusing member and the outer peripheral end surface of the color conversion member is kept constant . 4. The light emitting device according to claim 1, wherein an emission wavelength of the light emitting element is in a visible light region . 5. 5. The light emitting device according to claim 1, wherein a thickening material having a particle diameter of 10 nm or less is mixed in the light diffusing member . The light-emitting device according to claim 1 , wherein the color conversion member has a refractive index of 1.5 or more. 2. The light-emitting device according to claim 1, wherein the light diffusing member disperses particles having a particle size of 500 nm or more and 10 μm or less in a resin transparent to light emitted from the light-emitting element and light converted by the color conversion member. A light-emitting device comprising a material made of

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