JP5650885B2 - Wavelength conversion sintered body, light emitting device using the same, and method for producing wavelength conversion sintered body - Google Patents

Description

  The present invention relates to a wavelength conversion sintered body capable of emitting light with reduced color unevenness over substantially the entire light emitting region, a light emitting device including the same, and a method for manufacturing the wavelength conversion sintered body.

  Conventionally, by combining the emitted light emitted from the light source and the wavelength conversion member that can emit light of a hue different from the light source color when excited by this emitted light, various emission colors are emitted by the principle of light color mixing Possible light emitting devices have been developed. Furthermore, light-emitting devices using semiconductor light-emitting elements such as light-emitting diodes (LEDs) and laser diodes (LDs) as light sources have attracted attention as illumination, and further improved output and uniform light distribution An emission color is required. In particular, when adopting the above-mentioned illumination as a projector such as a headlight of a car or a floodlight, a uniform light distribution is important.

For this reason, Patent Document 1 discloses a technique that suppresses a change in light shade depending on an observation angle by performing uneven processing on the surface of the member when the wavelength conversion member is used. For example, the semiconductor light emitting device 801 shown in the cross-sectional view of FIG. 15 converts an LED 805 that emits the first light L and a part of the first light L into second light having a longer wavelength than the first light. A fluorescent plate 807. The fluorescent plate 807 includes a light incident surface 802 for receiving the first light L and a light emitting surface 803 for emitting the second light and the first light L. The light incident surface 802 and the light of the fluorescent plate 807 are provided. The emission surface 803 is formed in an uneven shape. Then, the first light L emitted from the LED 805 is diffused and emitted from the fluorescent plate 807 due to refraction in the uneven shape provided on the fluorescent plate 807. As a result, the ratio of the intensity of the first light can be evenly distributed over the entire observation angle, and the change in the light shade at the light emitting portion can be suppressed. Further, Patent Document 2 discloses a light emitting device in which irregularities are provided only on the light emitting surface side of a plate member for wavelength conversion.
JP 2005-268323 A JP 2007-109946 A JP 2002-305328 A

  However, the concavo-convex processing of these wavelength conversion members has a risk of producing a deteriorated layer or strain on the processed surface, has low processing reliability, and has a difficulty in obtaining a processed surface having a complicated shape.

  Therefore, as a result of intensive studies, the present inventors easily formed an uneven surface that can effectively disperse light with the surface of the wavelength conversion sintered body in order to reduce luminance unevenness or color unevenness in the light distribution region. I found new things I can do. Furthermore, in the wavelength conversion sintered body having the uneven surface with enhanced diffusibility, the phosphor particles are placed in a specific arrangement state to further disperse the light on the uneven surface, and as a result, the color mixing ratio of the light component is increased. It can be approximately equal. As described above, an object of the present invention is to provide a wavelength conversion sintered body capable of reducing color unevenness in a light distribution region and emitting high-luminance light, a light emitting device using the same, and a method for manufacturing the wavelength conversion sintered body. It is to provide.

In order to achieve the above object, a first method of manufacturing a wavelength conversion sintered body according to the present invention includes a first step of obtaining a sintered body by mixing and sintering inorganic powder and phosphor powder, Etching the sintered body to form a plurality of recesses on the surface of the sintered body, and in the second step, etching the sintered body at 260 ° C. or higher, the phosphor particles in the sintered body, causes preferentially soluble than inorganic particles in the sintered body, the inorganic material of the surface of the sintered body can be etched so as to be granulated.

According to the manufacturing method of the second wavelength conversion sintered body of the present invention, the etching can and wet etching.

Further, according to the manufacturing method of the third wavelength converting sintered body of the present invention, the inorganic material can be a Al ₂ O _3.

  Furthermore, according to the fourth method for producing a wavelength conversion sintered body of the present invention, it is possible to include a third step of polishing the sintered body before the second step.

  Furthermore, according to the fifth method for producing a wavelength conversion sintered body of the present invention, the concave portion can have an irregular shape.

  Furthermore, according to the sixth method for producing a wavelength conversion sintered body of the present invention, the concave portion can have a shape in which phosphor particles in the sintered body are dissolved.

Furthermore, according to the seventh wavelength conversion sintered body of the present invention, the wavelength conversion sintered body is a sintered body of an inorganic substance and a phosphor and has a plate-like shape having the first and second main surfaces. The wavelength conversion sintered body includes a surface layer in which a plurality of recesses are provided on at least the first main surface, and a central layer inside the surface layer, and the wavelength conversion sintered body. The phosphor particles contained in the body are distributed more in the central layer than in the surface layer, and the surface layer can have a granular inorganic substance.

  Furthermore, according to an eighth light-emitting device of the present invention, the light-emitting device includes the above-described wavelength conversion sintered body and a light-emitting element, and the light emitted from the light-emitting element on the first main surface. Can be a light-receiving surface that receives light or a light-emitting surface that emits the received light.

  Furthermore, according to the ninth light emitting device of the present invention, the second main surface is a smooth surface from which the central layer is exposed, and the light emitting element is disposed on the second main surface side. The first main surface can be the light emitting surface.

  According to the tenth light emitting device of the present invention, a plurality of light emitting elements are arranged on the second main surface side of one wavelength conversion sintered body, and the first main surface is used as the light emitting surface. Can do.

  In the wavelength conversion sintered body of the present invention, the surface layer is porous, and the surface is processed into irregular irregular shapes. As a result, the wavelength-converted secondary light can be effectively reflected or refracted on the processed surface and scattered in an irregular direction, and the directivity of the light is relaxed. That is, uneven distribution of light distribution on the light emitting surface can be reduced, and unevenness in luminance and color can be eliminated. In particular, the structure in which the inorganic particles are exposed, that is, the phosphor particles are arranged apart from the processing surface, so that the wavelength-converted light from the phosphor particles can be prevented from being emitted noticeably on the light emitting surface. That is, since the wavelength-converted light can be sufficiently diffused on the processed surface, light emission with substantially uniform color mixing ratio can be obtained over substantially the entire light emitting surface. As a result, the light extraction efficiency can be increased because it can be used effectively even in a light emission region that may have been reduced by color unevenness. Moreover, deterioration of the phosphor particles can be suppressed by not exposing the phosphor particles to the surface.

  Moreover, according to the manufacturing method of the wavelength conversion sintered compact of this invention, a part of wavelength conversion sintered compact is melt | dissolved chemically by wet etching. That is, the erosion region of the wavelength conversion sintered body can be selected based on the difference in the dissolution rate of the material components, and the formation of voids and the arrangement positions of the phosphor particles can be easily controlled. Furthermore, the bonded region of the particles in the sintered body can be cut without applying stress, and the outer surface shape of the particles can be exposed by substantially no strain processing. As a result, a void having a complicated shape can be formed, and the scattering property of light, particularly secondary light can be further enhanced. That is, it is possible to satisfy both the formation of irregular irregularities on the surface of the wavelength conversion sintered body and the arrangement of the phosphor particles in a predetermined manner at substantially the same time.

  Embodiments of the present invention will be described below with reference to the drawings. However, the examples shown below exemplify a wavelength conversion sintered body for embodying the technical idea of the present invention, a light emitting device using the same, and a method for manufacturing the wavelength conversion sintered body, This invention does not specify the wavelength conversion sintered compact, the light-emitting device using the same, and the manufacturing method of a wavelength conversion sintered compact to the following. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the examples are not intended to limit the scope of the present invention only unless otherwise specified, but are merely illustrative examples. Only.

  Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing. In addition, the contents described in some examples and embodiments may be used in other examples and embodiments. Further, in this specification, the term “upper” as used on a layer or the like is not necessarily limited to the case where the upper surface is formed in contact with the upper surface, but includes the case where the upper surface is separated from the upper surface. It is used to include the case where there is an intervening layer between them. In the present specification, the covering member may be described as a sealing member.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view of a wavelength conversion sintered body 500 according to the first embodiment. The wavelength conversion sintered body 500 contains inorganic particles 504 and phosphor particles 12 that can convert the wavelength of light. In the example of the wavelength conversion sintered body 500 in FIG. 1, an inorganic powder as a raw material for the inorganic particles 504 and a phosphor powder as a raw material for the phosphor particles 12 are mixed and sintered to obtain a sintered body.

  In the wavelength conversion sintered body 500, the vicinity of the surface layer exposed to the outside is formed in an uneven shape. The recesses 503 constituting the unevenness are not uniform in depth and inner surface shape, that is, irregular. In the unevenness formation region in the surface layer, the surface layer 505 is formed so as to have a void between the inorganic particles 504, that is, a surface layer 505 processed into a porous shape. On the outermost surface of the surface layer 505, at least a part of the void communicates with the outside, that is, an open recess is formed to constitute the recess 503 of the wavelength conversion sintered body 500.

  The concave portion 503 has such a shape that particles of the material component of the sintered body, in particular, the phosphor particles are removed, that is, at least part of the inner surface shape of the concave portion 503 is the surface of the particle in the material component of the sintered body. It substantially conforms to the shape, or satisfies the similar relationship with the surface shape of the particles of the material component of the sintered body. Specifically, at least a part of the inner surface of the concave portion 503 of the surface layer 505 is rounded. Further, the concave portion and at least a part of the outer surface of the spherical particle of the phosphor 12 can be fitted or the concave portion. At least a part of the inner surface shape of the phosphor particle 12 can substantially coincide with a shape obtained by enlarging or reducing the surface shape of the phosphor particles 12.

  Further, in the surface layer of the wavelength conversion sintered body 500, the inorganic particles 504 cover the distribution region of the phosphor particles 12, and the covered region of the inorganic particles 504 constitutes the surface layer 505 and is exposed to the outside. In addition, the surface layer 505 has a plurality of pores. Therefore, more phosphor particles are distributed in the central layer 506 spaced from the surface layer 505 than in the surface layer 505. In other words, the central layer 506 has a lower porosity than the surface layer 505. In the example of FIG. 1, the content of the phosphor particles 12 in the wavelength conversion sintered body 500 is set to 5% by weight or more, and the light amount of the wavelength conversion light is adjusted to a suitable range. Further, the phosphor particles 12 are distributed in a state of being smaller than the central layer 506 in the surface layer 505, and are disposed in a substantially uniformly diffused state in the central layer. In the present specification, the “porosity” means the ratio of the volume of the gap contained in the total volume of the wavelength conversion sintered body. In the case of a sintered body having voids at the time of molding, the density of the phosphor particles mainly in the observation cross section is lower on the surface layer side than on the central layer side, for example, 0.1 times or less, preferably 0.01. A transmissive region lowered to a double or less is provided, and a phosphor-free transmissive region having a density of approximately 0 is provided on the surface layer.

  The wavelength conversion sintered body 500 includes a first main surface 501 that can receive or emit light, and a second main surface 502 that faces the first main surface 501, and preferably has a plate shape. And In the example of FIG. 1, for the sake of convenience, the first main surface 501 and the second main surface 502 are distinguished from the light emitting surface and the light receiving surface, respectively.

  FIG. 2 is a schematic cross-sectional view of the wavelength conversion sintered body 500, and is an explanatory view schematically illustrating how light passes through the wavelength conversion sintered body 500. Members having the same functions as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. Specifically, FIG. 2 (a) shows a wavelength-converted sintered body 600 that has been surface-polished or processed, and FIG. 2 (b) shows the wavelength-converted sintered body 500 of the first embodiment. 12 are arranged in a substantially uniform manner. However, in the example of FIG. 2A, the surface layer 505 contains phosphor particles, and a part of the phosphor particles is exposed to the light emitting surface 601. On the other hand, in the example of FIG. 2B, the distribution of the phosphor particles 12 in the surface layer 505 is limited. That is, the inorganic particles 504 cover the phosphor particles 12, and the light emitting surface 501 is covered with this coating region. Configure. Therefore, preferably, the phosphor particles 12 are arranged apart from the light emitting surface 501 and are not exposed to the outside. That is, if the depths from the respective light emitting surfaces 601 and 501 to the upper end of the distribution region of the phosphor particles 12 are d1 and d2, the relationship d1 <d2 is satisfied, and d1≈0 as the polishing roughness decreases. In the wavelength conversion sintered body 500 of FIG. 2B, the phosphor is disposed behind the emission observation surface. In this way, the distribution of the phosphor particles is low, that is, the separation region and the coating region are formed in the transmission region where the inorganic particles are largely distributed. As the phosphor in the transmission region decreases, the separation and the coating region are formed. The effect can be enhanced.

  A part of the primary light incident from the light receiving surfaces 502 and 602 facing the light emitting surfaces 501 and 601 proceeds to the phosphor particles 12 to be converted into secondary light. Here, in the example of FIG. 2A, since the phosphor particles 12 are disposed on the light emitting surface 601 of the wavelength conversion sintered body 600 or in the vicinity thereof, the secondary light does not travel to the uneven portion of the light emitting surface 601. In addition, since the exposed phosphor particles are directly emitted to the outside, they are not sufficiently scattered and diffused. As a result, the secondary light is concentrated and emitted on the light emitting surface, that is, the primary light and the secondary light are not sufficiently mixed on the light emitting surface 601 that is the light emission observation surface, and color unevenness tends to occur. is there.

  On the other hand, in the wavelength conversion sintered body 500 of the first embodiment, the phosphor 12 is positioned below the light emitting surface 501 by the depth d2, and therefore the optical path until the secondary light reaches the light emitting surface 501 is reached. The secondary light is sufficiently scattered and diffused by the uneven shape on the light emitting surface and further by the transmission region. Thereby, the hue of the secondary light does not stand out on the light emitting surface 501, and substantially uniform color mixing light can be obtained. In particular, by setting the depth d2 from the light emitting surface 501 to the upper end of the distribution region of the phosphor particles 12 to 5% to 40% of the total film thickness of the wavelength conversion sintered body 500, the above uneven surface, Furthermore, the light diffusibility of the wavelength converted light by the transmission region can be effectively enhanced. If the depth d2 is smaller than 5%, the scattering property is weak, that is, approximate to the wavelength conversion sintered body 600 of FIG. On the other hand, if it is larger than 40%, the ratio of the secondary light in the mixed color light becomes minute, and the desired mixed color light cannot be obtained. Further, since the surface layer 505 does not substantially contain the phosphor particles 12, the depth d2 to the uppermost distribution region of the phosphor particles 12 is the distance from the light emitting surface 501 to the gap formed at the most distance. Approximately equivalent to depth. In addition, although the uneven | corrugated | grooved area | region is illustrated as a part of transmissive area | region, you may have all, for example, set it as 20 to 80% of a transmissive area | region.

(Method for producing wavelength conversion sintered body)
The wavelength conversion sintered body can be produced by melting an inorganic powder using a discharge plasma sintering method (SPS method) and then cooling a mixture of phosphor powder and inorganic powder. In the SPS method, a pulsed large current is applied to a powder mixture of phosphor powder and inorganic powder at a low voltage, and the inorganic powder is melted by the high energy of discharge plasma generated instantaneously by a spark discharge phenomenon. is there. In the first embodiment, aluminum oxide (Al ₂ O ₃ ) as an inorganic substance and YAG powder as a phosphor are kneaded and a sintered body is produced by the SPS method. Although there are few gaps with this sintering method and the light conversion member of the light emitting device has excellent characteristics, other sintering methods may be used.

For example, an SEM image having a cross section as shown in FIG. 4 can be obtained. In the figure, the whitened granular portion is the YAG phase, and the base material portion covering the YAG phase is the alumina phase (Al ₂ O ₃ ). From the figure, it can be seen that the YAG phase is substantially uniformly dispersed in the alumina phase. Depending on the conditions at the time of manufacture, in addition to the two-phase structure of the phosphor phase (phosphor particles) in the matrix (inorganic particles) as seen in the figure, the granular form in which each particle aggregates, etc. It can be in various forms, and preferably has a phase structure with few voids.

This sintered body is sliced with a predetermined thickness, the surface is further polished as appropriate, and then unevenness processing is performed by wet etching. Here, in this specification, “polishing” is equivalent to grinding, and is used in a broad sense including cases where the surface is smoothed or roughened, but unless otherwise specified. Indicates polishing for smoothening. In the first embodiment, the polishing conditions are as follows. Polishing is performed with a # 800 diamond grindstone at a grindstone rotation speed of 80 rpm, a workpiece rotation speed of 80 rpm, and a pressure of 1.7 MPa, so that the final wavelength conversion sintered body has a thickness of 150 μm. In the etching, a mixed solution of phosphoric acid and sulfuric acid (36:74) is heated to 300 ° C., etched in the solution for 5 minutes, and then washed with water. Thereby, the bonding area between the powder particles in the sintered body is preferentially dissolved and granulated again. At the same time, the material component is selectively dissolved by the difference in the etching rate of the material component, and a void is formed on the remaining surface on the substrate side. Specifically, YAG is also dissolved in a mixture of phosphoric sulfuric acid (36:74) at 200 ° C., while Al ₂ O ₃ begins to dissolve at about 260 ° C. Preferably, the temperature of the etching solution is set in a range of 280 ° C to 305 ° C. Since the etching rate of YAG is faster than that of Al ₂ O ₃ , YAG is preferentially dissolved and Al ₂ O ₃ is exposed on the surface. In the surface layer, voids are generated due to the loss of the YAG particles, and a part thereof constitutes a recess that communicates with the outside.

  The above processing may be performed on any surface of the sintered body. For example, either the first main surface or the second main surface may be processed on one side or on both sides. That is, one-side processing in which one main surface is subjected to uneven processing and the other main surface is a polished surface or a smooth surface may be used. As a result, in the light emitting device in which the wavelength conversion sintered body described later is combined with the light source, the light distribution chromaticity unevenness can be reduced by processing the light emitting surface side as described above with reference to FIG. Further, by setting the processed surface of the wavelength conversion sintered body to the side adjacent to the light source, that is, the light receiving surface side, the light propagating through the light transmitting member is preferably scattered and reflected to the light emitting surface side, so that the light emitting device Luminance unevenness in the emitted light can be reduced. In addition, by providing an uneven region and an inorganic region on the light receiving surface side, there are few particles of the wavelength conversion member that serves as a light-emitting source of light scattering and converted light in the vicinity of the entrance for coupling with a light-emitting element, etc. Is not present, thereby reducing the amount of light returning to the light emitting element and the amount of light traveling toward the light receiving surface, thereby increasing the efficiency of incidence on the light transmitting member and thus increasing the efficiency of light emission from the light emitting surface. be able to. In addition, the unevenness region improves the adhesion between the light-emitting element and the sealing member. On the other hand, since the uneven area and the inorganic area on the light receiving surface side increase the light extraction efficiency as described above, the amount of light leaking to the light emitting element side and the sealing member may increase. Furthermore, by using both the light receiving surface and the light emitting surface of the wavelength conversion sintered body as processed surfaces, it is possible to reduce light distribution chromaticity unevenness and chromaticity unevenness on each processed surface. On the other hand, if the concave and convex portions are provided on both sides, the light confinement rate in the light conversion sintered body and the light emission rate from the light receiving surface side may increase depending on the combination of processing, depending on the desired characteristics As appropriate, processing is performed on one side and adjustment of the inorganic and uneven regions, or processing of different uneven portions on both sides and adjustment of each region are performed.

  In addition, regarding the correlation between the conditions such as YAG particles (particle size) of the SPS method and the voids after the etching treatment, the surface state after the etching is the etching treatment time, the crystalline state after sintering, the size of the crystal, Depends on particle size. For example, it is preferable to reduce the particle size because the light distribution chromaticity can be further improved. Below, the comparative example and the Example which compared and examined the example which made the uneven | corrugated processing conditions various are shown. In the comparative examples and examples, when the production method is not particularly described, the production method is the same as described above.

(Example 1, Example 2, Example 3)
In Examples 1 to 3 shown below, the correlation between the surface processing method of the wavelength conversion sintered body in the present invention, the processed surface state, and the cross-sectional state is investigated. That is, it is set as Example 1, 2, 3 by the difference in the pre-processing conditions (A-C) before an etching, Furthermore, the etching surface at the time of giving various etching processing conditions (ae) with respect to each Example, and its Compare and examine the cross-sectional state.

First, Al ₂ O ₃ and YAG (10 wt%) are sintered by the SPS method, and then the sintered body is sliced and subjected to carbon baking treatment at 1400 ° C. Hereinafter, this plate-like YAG-Al ₂ O ₃ sintered body is referred to as “YAG sintered plate”. Then, the pretreatment applied to the YAG sintered plate before etching is as follows: Polishing (A) —Example 1, Blasting (B) —Example 2, No pretreatment (C) —Example 3 There are three types. The etching solution is a mixed acid solution of phosphoric acid (36%) / sulfuric acid (74%), and the etching conditions are 260 ° C.-1 min (a), 300 ° C.-1.5 min (b), 300 ° C.-3 min. (C), 300 ° C. for 6 minutes (d), and 300 ° C. for 12 minutes (e). In order to prevent the YAG sintered plate from cracking, an etching process of 200 ° C.-1 min is actually performed before and after the above conditions, but the description is omitted.

  The surface state by the combination of these etching pretreatments (A to C) and etching treatments (a to e) was observed by SEM, and the results are shown in FIG. From FIG. 3, the depth of the concave portion is different if the etching is performed for a short time with or without polishing, but if the etching is performed for a long time, there is no correlation between the etching processing time and the processed surface state. It is done. From this, it can be said that it is preferable to set the etching time to 3 minutes or more because the dependence of the surface state before etching is eliminated. From a different perspective, it is easier for the etching solution to penetrate into the sintered body when the surface of the sintered body is rougher than the smooth surface or has fine voids and holes, so that the same processed surface state is obtained. It is possible to shorten the etching processing time until it becomes.

Further, in the pretreatment of Example 1-polishing (A), no etching, processing under the conditions (a), (c), and (e) above, and no processing (without pretreatment of Example 3 (C)) For the YAG sintered plate without etching), the cross-sectional state was observed by SEM, and the result is shown in FIG. 4 together with the enlarged image of the processed surface state. As shown in FIG. 4, the wet etching process preferentially dissolves the YAG particles in the surface layer of the YAG sintered plate, leaving the Al ₂ O ₃ inorganic base material to form irregular irregularities. Understandable.

(Embodiment 2)
A light emitting device capable of emitting light having a desired wavelength by combining the wavelength conversion sintered body 500 of the first embodiment with a light source will be described in detail below as a second embodiment. FIG. 5 is a schematic cross-sectional view of the light emitting device 1 according to the second embodiment. The light emitting device 1 includes a light emitting element 10, a light transmitting member 15 that transmits light emitted from the light emitting element 10, and a light It is mainly composed of a covering member 26 that covers a part of the transmitting member 15. The light emitting element 10 is mounted on the wiring board 9 via the conductive member 24, and the light transmitting member 15 is optically connected above the light emitting element 10. In the example of FIG. 5, the electrode surface 4 faces the wiring board 9 and is electrically connected to the wiring (not shown), that is, face-down mounted so that the growth substrate 5 side is close to the light transmitting member 15. As shown in FIG. 3, light is mainly extracted from the growth substrate 5 side by joining to the light transmission member 15.

  Further, the light transmission member 15 is configured by a wavelength conversion member capable of converting the wavelength of at least a part of the light emitted from the light emitting element 10, and specifically, the wavelength conversion sintered body 500 of the first embodiment. . Thereby, a part of the emitted light from the light emitting element 10 is additively mixed with the secondary light whose wavelength is converted by the wavelength conversion member, and light having a desired wavelength can be emitted from the light emitting device. Furthermore, since the primary light and the secondary light can be sufficiently diffused on the light emitting surface 15a through the wavelength conversion sintered body 500 provided with the unevenness processing and the arrangement position of the phosphor particles on the surface, the substantially uniform By realizing a color mixing ratio, emitted light with reduced color unevenness can be obtained. In particular, when a plurality of light sources are optically connected to one light transmissive member 15, the light diffusibility is further increased by using the light transmissive member 15 as the wavelength conversion sintered body 500. It is preferable that even light sources with high directivity can be diffused effectively on the light emitting surface, and the installation of a separate member such as a diffusion filter can be omitted. Therefore, the “light transmitting member” in the following description can be applied to the “wavelength conversion sintered body”.

  The light transmitting member 15 includes a light receiving surface 15b that receives light from the light emitting element 10, and a light emitting surface 15a that emits the received light and that constitutes the outer surface of the light emitting device 1. A side surface 15c that is substantially perpendicular to 15a and parallel to the thickness direction is provided. Further, a part of the light transmitting member 15 is covered with the covering member 26, and the light emitting surface 15 a that emits light to the outside is exposed from the covering member 26. Preferably, the exposed surface of the covering member 26 is substantially the same surface as the light emitting surface 15a or an outer surface that recedes from the light emitting surface 15a toward the light receiving surface 15b, so that the light transmitting member 15 that is a window portion is exposed. The light emitted from the light emitting surface 15a can be prevented from being blocked by the covering member 26.

  The covering member 26 includes the light reflecting member 2 capable of reflecting light, and covers at least the side surface 15c of the light transmitting member. Thereby, the following operations and effects can be obtained. First, light can be prevented from leaking from the side surface 15c region. Second, in comparison with the light emission from the light emitting surface 15a, light having a color difference that cannot be ignored is prevented from being emitted outward from the side surface 15c, and color unevenness in the entire emission color is prevented. Generation can be reduced. Third, by reflecting the light traveling in the direction of the side surface 15c toward the light extraction direction and further restricting the light emitting region to the outside, the directivity of the emitted light is enhanced and the light emitting surface 15a Brightness can be increased.

  Further, the covering member 26 covers a part of the light receiving surface 15 b in addition to the side surface 15 c of the light transmitting member 15. Specifically, as shown in FIG. 5, a covering member 26 is filled between the light transmitting member 15 and the wiring substrate 9, so that the area around the light emitting element 10, that is, the area facing the light emitting element 10 on the light receiving surface 15 b is formed. The removed region is sealed with the covering member 26. With this configuration, an optical connection region between the light emitting element 10 and the light transmission member 15 and a coating region of the covering member 26 are provided on the light receiving surface 15b of the light transmitting member, and the optical connection region is limited to this optical connection region. The primary light of the light emitting element 10 can be guided to the light transmitting member 15 side with high efficiency. Further, the light that has traveled to the light receiving surface 15b side of the light transmitting member can be reflected to the light extraction side by the covering member 26 in the covering region. Further, when the surface layer 505 is provided on the light receiving surface 15 b side of the light transmitting member 15, it is preferable to impregnate the covering member 26 in the concave portion 503 in the surface layer 505. As a result, the light transmitting member 15 and the light emitting element 10 can be optically coupled stably, and the difference in refractive index between the two regions constituting the interface of the light receiving surface 15b is reduced to increase the light incident rate to the light transmitting member 15. It is done. As a result, the light extraction efficiency can be improved, and the output of the entire emitted light can be improved.

  Below, each member and structure of the light conversion member and sintered body in the present invention, and the light emitting device 1 will be described.

(Light emitting element)
As the light emitting element 10, a known one, specifically, a semiconductor light emitting element can be used, and examples thereof include an LED and an LD. A GaN-based semiconductor is preferable because it can emit light at a short wavelength that can efficiently excite a fluorescent substance. The following description will be made using a GaN-based semiconductor light emitting element. Further, the semiconductor is not limited thereto, and may be a semiconductor such as ZnSe, InGaAs, or AlInGaP.

FIG. 6 is a schematic cross-sectional view illustrating an example of the light-emitting element 10, and the structure of the light-emitting element 10 will be described. Light emitting element 10, a pair of opposed major surfaces, on a growth substrate 5 as one main surface side, a semiconductor structure 11, the general formula _{In x Al y Ga 1-xy} N (0 ≦ x, 0 A nitride semiconductor layer composed of ≦ y and x + y ≦ 1) is laminated. In the semiconductor structure 11, a first nitride semiconductor layer 6 (n-type layer), an active layer 8, and a second nitride semiconductor layer 7 (p-type layer) are stacked in order from the lower layer side. As the composition of the well layer, InGaN is preferably used in the visible light / near ultraviolet region. In addition, by including Al in the well layer, a wavelength shorter than the wavelength 365 nm which is the band gap energy of GaN can be obtained. The wavelength of light emitted from the active layer can be a wavelength of about 360 nm to 650 nm, preferably 380 nm to 560 nm, depending on the purpose and application of the light emitting element. The first nitride semiconductor layer 6 and the second nitride semiconductor layer 7 are each provided with a first electrode 3A and a second electrode 3B that are electrically connected. Each electrode (particularly, the second electrode 3B) may be formed with the light-transmitting conductive layer 13 interposed therebetween. Then, only a predetermined surface of each electrode is exposed, and the other part is covered with an insulating protective film 14.

  Here, the electrode provided in the semiconductor layer preferably has a structure in which a pair of positive and negative electrodes is provided on one main surface side, but is not limited thereto, and may be a structure in which each electrode is provided to face each main surface of the semiconductor layer. good. Further, regarding the mounting form of the light emitting element, for example, in an element structure having positive and negative electrodes on the same surface side, it can be face-up mounted with the electrode forming surface side as a main light extraction surface, and a growth substrate facing the electrode forming surface Flip chip mounting with the main light extraction surface as the side can also be adopted. Hereinafter, each component of the semiconductor light emitting element 10 will be specifically described.

(Growth substrate)
The growth substrate 5 is a substrate on which the semiconductor layer 11 is epitaxially grown. In the nitride semiconductor, sapphire or spinel whose main surface is any one of the C-plane, R-plane, and A-plane is preferable. A nitride semiconductor substrate such as GaN or AlN is also suitable. Further, the growth substrate 5 may be removed after the semiconductor layer 11 is formed. Even if it is a translucent board | substrate, light extraction efficiency and an output can be improved by removing a board | substrate. Further, after removing the growth substrate 5, another conductive substrate or a light-transmitting substrate can be formed and bonded to the exposed semiconductor layer, which may be the light-transmitting member 15.

(Translucent conductive layer and electrode)
The translucent conductive layer 13 is preferably an oxide containing at least one element selected from the group consisting of Zn, In, and Sn. Specifically, a light-transmitting conductive layer 13 containing an oxide of Zn, In, Sn, such as ITO, ZnO, In ₂ O ₃ , SnO ₂ , preferably ITO is used. By forming the conductive layer on almost the entire surface of the exposed p-type semiconductor layer 7, the current can be spread uniformly over the entire p-type semiconductor layer 7. Alternatively, the light-transmitting conductive layer 13 may be exposed from the pad electrode and light may be extracted therefrom. The electrodes 3A and 3B are formed on or in contact with the semiconductor structure without providing the light-transmitting conductive layer. For example, it is made of any metal of Au, Pt, Pd, Rh, Ni, W, Mo, Cr, Ti, Ag, Al, alloys thereof, or combinations thereof. Moreover, you may make it function as a pad electrode which electrically connects the light emitting element 10 and an external electrode. For example, a conductive member 24 such as an Au bump or a eutectic metal layer is disposed on the surface of the metal electrode layer, and is electrically connected to the opposing external electrode via the conductive member. In addition, after forming the electrode layer, the insulating protective film 14 can be formed on almost the entire surface of the semiconductor light emitting device 10 except for the connection region with the external region, and an exposed region in each electrode is obtained. For the protective film 14, SiO ₂ , TiO ₂ , Al ₂ O ₃ , polyimide, or the like can be used. Furthermore, by providing a light reflecting structure such as a dielectric multilayer film or a metal reflecting film on the translucent conductive layer 13, the electrode forming surface side can be made the light reflecting side. Moreover, it can also be set as the electrode structure which provided the light-reflective electrode, such as Ag and Al, in the semiconductor layer not through a translucent conductive layer.

(Wiring board)
On the other hand, in the light-emitting device 1 of FIG. 5, the wiring board 9 on which the light-emitting element 10 is mounted can use a wiring board on which at least the surface is connected to the electrode of the element. The material of the substrate is a crystalline substrate such as single crystal or polycrystal of AlN, a sintered substrate, ceramic such as alumina, glass, a semi-metal or metal substrate such as Si, and an AlN thin film on the surface thereof. A laminate or a composite such as a substrate on which a layer is formed can be used. A metal substrate, a metallic substrate, and a ceramic substrate are preferable because of high heat dissipation. In addition to the wiring board, for example, in a light emitting element whose main light emitting side is the electrode formation surface side, a form in which the electrode of the element is wire-connected to the electrode of the device by face-up mounting on a board without wiring may be used.

(Light transmissive member, wavelength conversion sintered body)
The light transmitting member 15 in FIG. 5 is configured to include the light emitting element 10 in a plan view from the light emitting surface 15a. In other words, as illustrated in FIG. 5, the side surface 15 c of the light transmitting member 15 protrudes outward from the end surface 33 that forms the side surface of the light emitting element 10. As a result, light emitted from the optically connected light emitting element 10 can be directly received by the light receiving surface 15b wider than the upper surface of the light emitting element 10, so that there is little loss of light flux.

  The light transmissive member 15 is preferably made of a light transmissive member having a wavelength conversion member capable of converting the wavelength of at least part of the light passing therethrough. Specifically, in addition to the phosphor and the light-transmitting inorganic sintered body, a glass plate provided with a light conversion member, or a phosphor crystal of the light conversion member or a single crystal having a phase thereof, There are aggregates and porous materials of a polycrystalline body, an amorphous body, a ceramic body, or phosphor crystal particles and an appropriately added translucent member. In addition, a translucent member such as a translucent resin mixed and impregnated therein, or a translucent member containing phosphor particles, such as a molded body of a translucent resin, is used.

  In addition, the shape of the light transmitting member 15 is not particularly limited. However, when the light transmitting member 15 is formed in a plate shape, the coupling efficiency with the emission surface of the light emitting element 10 configured to be planar is good, and the main surface of the light transmitting member 15 is substantially the same. Can be easily aligned to be parallel. In addition, by making the thickness of the light transmitting member 15 substantially constant, it is possible to suppress the uneven distribution of the configured wavelength conversion member, and as a result, the wavelength conversion amount of light passing therethrough is made substantially uniform, and the ratio of color mixing is stabilized, Color unevenness at the light emitting surface 15a can be suppressed. On the other hand, the light-emitting surface and the light-receiving surface of the light transmitting member 15 are not limited to flat surfaces, but have a surface shape such as a concavo-convex surface as well as a shape having a curved surface as a whole, and condensing and dispersing light. For example, an optical shape such as a lens shape can be used, and such an optical member can be provided on the light transmitting member, and the light orientation can be controlled. It can also be set as the light-emitting device.

  In the light emitting device 1, a plurality of wavelength converting members or light transmitting members having the function thereof may be provided. For example, the light converting member may be a mixture of two or more kinds of phosphors. In addition, a plurality of light transmissive members having a plurality of wavelength conversion members having different wavelengths or a plurality of light transmissive members having the function may be provided, for example, a laminate of a plurality of light transmissive members. Further, one wavelength converting member or a light transmitting member having the function thereof, and separately, on the light extraction window of the light emitting device or on the light path in the device from the light source to the light source, for example, the light transmitting member and the light emitting element The light conversion part which has a light conversion member can also be provided between a light emitting element and a coating | coated member in the coupling member.

  As described above, the inorganic particles and the phosphor particles are preferentially and selectively removed by utilizing the rate difference by the etching process, and the inorganic region and the uneven region are provided on the surface layer side. Therefore, it is preferable to select those having such a relationship. Also, in the light diffusion in the light transmitting member, since the characteristics change according to the difference in refractive index between them, it is preferable to select a material having a desired relationship. Specifically, the same material system is preferable because each composition ratio, raw material ratio, and the like can be appropriately adjusted. For example, a YAG (LAG) aluminate phosphor is preferably an aluminum oxide. In addition to silicate phosphors, silicon nitride phosphors can be selected as long as they are phosphors of silicate and silicon compounds. Also, in the sintered body, the crystal of the molded body is preferable because it is excellent for a light emitting device. Hereinafter, the wavelength conversion member, the phosphor and the inorganic powder and particles will be described.

The wavelength conversion member can be suitably combined with a blue light emitting element to emit white light. As a typical phosphor used for the wavelength conversion member, a YAG phosphor (yttrium, aluminum, Garnet) and LAG-based phosphors (lutetium, aluminum, garnet). In particular, (Re _1-x Sm _x ) ₃ (Al _1-y Ga _y ) ₅ O _{12 in} high brightness and long time use. : Ce (0 ≦ x <1, 0 ≦ y ≦ 1, where Re is at least one element selected from the group consisting of Y, Gd, La, and Lu). Further, a phosphor containing at least one selected from the group consisting of YAG, LAG, BAM, BAM: Mn, (Zn, Cd) Zn: Cu, CCA, SCA, SCESN, SESN, CESN, CASBN, and CaAlSiN ₃ : Eu. Can be used. In addition to the light transmissive member, the wavelength conversion member can also be provided, for example, between the light transmissive member and the light emitting element, and between the light emitting element and the covering member in the coupling member. Similarly, the light transmitting member, the wavelength converting member, and the sintered body can be disposed in the light emitting device. It is also possible to increase the reddish component using a nitride-based phosphor having yellow to red light emission, and to realize illumination with high average color rendering index Ra, light bulb color LED, and the like. Specifically, by adjusting the amount of phosphors having different chromaticity points on the CIE chromaticity diagram according to the light emission wavelength of the light emitting device, the phosphors are connected with each other on the chromaticity diagram. Any point can be made to emit light. In addition, nitride phosphors, oxynitride phosphors, and silicate phosphors that convert near-ultraviolet to visible light into a yellow to red region can be used. For example, L ₂ SiO ₄ : Eu (L is an alkaline earth metal), particularly (Sr _x Mae _1-x ) ₂ SiO ₄ : Eu (Mae is an alkaline earth metal such as Ca and Ba) and the like. Examples of nitride phosphors and oxynitride (oxynitride) phosphors include Sr—Ca—Si—N: Eu, Ca—Si—N: Eu, Sr—Si—N: Eu, and Sr—Ca—Si. —O—N: Eu, Ca—Si—O—N: Eu, Sr—Si—O—N: Eu, and the like. As the alkaline earth silicon nitride phosphor, the general formula LSi ₂ O ₂ N ₂ : Eu , general formula _{L x Si y N (2 /} 3x + 4 / 3y): Eu or _{L x Si y O z N (} 2 / 3x + 4 / 3y-2 / 3z): Eu (L is, Sr, Ca, One of Sr and Ca).

(Inorganic material and powder)
The above-mentioned sintered body, light-transmitting member and wavelength conversion member molded body contain inorganic particles, and in the specification, “inorganic powder” means a state used as a raw material before being compounded as a molded body. , “Inorganic substance” and “inorganic substance particle” mean a state after being combined as a fluorescent substance molded body, and the same applies to the phosphor and the light conversion member. The inorganic powder is used to hold the phosphor powder, and can function as a base material in the multiphase sintered body as described above. Further, there is no particular limitation as long as a part of the light emitted from the light emitting element or a part of the light emitted from the phosphor is transmitted. Specifically, the inorganic powder / particle is glass, ceramics or the like. The inorganic member powder is preferably glass because it has a relatively low softening point and is inexpensive.

  A general transparent dielectric inorganic material can be used as the inorganic powder. Specific examples include borosilicate glass, aluminum oxide, titanium oxide, niobium oxide, zirconium oxide, yttrium oxide, silicon oxide, and magnesium fluoride. In consideration of heat dissipation and light extraction efficiency, aluminum oxide is used. It is preferable. Further, the inorganic powder of the sintered body raw material has at least one of a phosphor composition to be mixed, a composition substantially the same as the crystal system of the phosphor, or a crystal system of the phosphor. It is preferable to have. Thereby, it can suppress that the conversion efficiency of fluorescent substance falls by the melt diffusion or thermal diffusion of fluorescent substance and an inorganic substance in a discharge plasma sintering process. In addition, since the interface between the phosphor and the inorganic substance can be substantially continuous in terms of composition and crystal, the loss of light at the junction interface between the phosphor and the inorganic substance can be reduced. Glass powder can be used as the inorganic powder. The glass powder 31 may be any material that transmits the light from the light emitting element and holds the phosphor when formed into a molded body. The magnitude | size of glass powder is not specifically limited, The thing of several nm-several mm can be used.

  Further, as the wavelength conversion function of the light transmitting member, in addition to the light emitting device using the light of the light emitting element and the mixed color light of the converted light, for example, the converted light by the ultraviolet light of the light emitting element or the mixed color light by the plurality of converted lights In addition, a light-emitting device that emits secondary light converted from primary light of the light-emitting element can be provided.

(Coating member / sealing member)
The material of the resin used as the base material of the sealing member 26 is not particularly limited as long as it is translucent, and it is preferable to use a silicone resin composition, a modified silicone resin composition, etc., but an epoxy resin composition, a modified epoxy A translucent insulating resin composition such as a resin composition or an acrylic resin composition can be used. Moreover, sealing members excellent in weather resistance, such as hybrid resins containing at least one of these resins, can also be used. Furthermore, inorganic materials having excellent light resistance such as glass and silica gel can be used. Furthermore, a lens effect can be provided by making the light emitting surface side of the sealing member have a desired shape, and light emitted from the light emitting element chip can be focused.

  Moreover, in Embodiment 2, the sealing member 26 contains the light reflective member 2 in the resin. By containing the light reflective member, the reflectance of the sealing member 26 is increased, and more preferably, the light is absorbed and the loss is reduced due to reflection by the light transmissive particles. That is, the emitted light from the light emitting element 10 is reflected by the covering member 26 covering the vicinity of the light emitting element 10 and guided to the light emitting element 10 side or the light transmitting member 15 side.

The light reflecting member 2 contained in the sealing member and the covering member 26 is one oxide selected from the group consisting of Ti, Zr, Nb, Al, and Si, or at least one of AlN and MgF. Specifically, it is at least one selected from the group consisting of TiO ₂ , ZrO ₂ , Nb ₂ O ₅ , Al ₂ O ₃ , MgF, AlN, and SiO _2. The light-reflecting member contained in the conductive resin, in particular, the light-transmitting particles, is one kind of oxide selected from the group consisting of Ti, Zr, Nb, and Al. And reflectivity, and the difference in refractive index from the substrate is increased, which is preferable. The light reflectance and leakage distance are adjusted by the content and filling rate of the light reflective member, and are preferably 20% by weight or more and a wall thickness of 20 μm or more, for example. In addition to a covering member in which translucent particles are mixed in such a translucent resin, a molded body of a porous material such as a sintered body or an aggregate of a light reflecting member may be used. However, they may be impregnated with resin.

(Additive components)
In addition to the light-reflective member 2 and the light conversion member, an appropriate member such as a viscosity extender can be added to the covering / sealing member 26 and the light transmitting member 15 depending on the intended use. A light emitting device having a directional characteristic can be obtained, for example, coloring the outer surface of the covering member to black in order to increase the desired emission color, the color of those members or the surface of the device, for example, the contrast with external light. Similarly, various colorants can be added as a filter material having a filter effect of cutting unnecessary wavelengths from extraneous light and light emitting elements.

(Adhesive)
An adhesive 17 is interposed at the interface between the light emitting element 10 and the light transmitting member 15, thereby fixing both members. The adhesive 17 is preferably made of a material that can effectively guide the light emitted from the light emitting element 10 toward the light transmitting member 15 and optically connect both members. Examples of the material include resin materials used for the above-described members. As an example, a translucent adhesive material such as a silicone resin is used. Further, for bonding between the light emitting element 10 and the light transmitting member 15, crystal bonding by thermocompression bonding or the like can be employed.

(Method for manufacturing light emitting device)
An example of a method for manufacturing the light emitting device 1 shown in FIG. 5 will be described below. First, bumps that are conductive members 24 are formed on the wiring board 9 or on the light emitting element 10 according to a flip chip mounting pattern. Next, the light emitting element 10 is flip-chip mounted through the conductive member 24. In this example, one LED chip is mounted side by side on the submount substrate 9 in an area corresponding to one light emitting device. The number of chips mounted depends on the size of the light emitting surface and the light transmitting member. Can be changed as appropriate. By using a plurality of light emitting elements 10, the total light flux is increased, and the luminance of the emitted light is increased. Moreover, the form which mounts the light emitting element 10 in this cavity using the mounting board | substrate which has a cavity structure may be sufficient.

  Next, a silicone resin as the adhesive 17 is applied to the back surface side of the light emitting element 10 (the back surface of the sapphire substrate or the nitride semiconductor exposed surface if the substrate is removed by LLO), and the light transmitting member 15 is laminated. . Thereafter, the silicone resin 17 is thermally cured to bond the light emitting element 10 and the light transmitting member 15 together.

  Further, a frame body having a predetermined size and shape is erected around the light emitting element 10. Here, the height of the frame and the cavity may be set lower than that of the light transmitting member 15. Then, a resin constituting the sealing member 26 is potted (dropped) so as to cover the side surface of the light transmitting member 15 in a frame body or a cavity standing around the light emitting element 10. At this time, the surface of the sealing member 26 is along the surface of the light transmitting member 15, that is, both surfaces are positioned substantially on the same plane, or are retracted to a lower position than the surface of the light transmitting member 15. To do. Then, after the sealing member 26, which is a resin, is cured, the frame body is removed, and dicing is performed with a broken line portion at a predetermined position, and the substrate is cut into a submount substrate size to obtain a light emitting device. In consideration of the mechanical strength of the light-emitting device, the light-emitting device may be provided with a frame.

  However, the arrangement method of the sealing member 26 that covers the periphery of the light emitting element 10 is not particularly limited. For example, it can also be provided by screen printing or transfer molding. Further, the light emitting element may not be provided with a form that is directly mounted on a predetermined mounting portion of the light emitting device, that is, a submount. Further, the submount substrate cut out individually, or a substrate to which a lens or the like is bonded and sealed can be used as a light emitting device.

  Hereinafter, other forms of the arrangement and superposition of the light transmitting member and the light emitting element will be described. In the alignment of the light transmissive member 15 with respect to the light emitting element 10, the side surface 15c of the light transmissive member 15 is positioned substantially on the same plane as the end surface 33 of the light emitting element 10, that is, both side surfaces are configured to be substantially flush. May be. Accordingly, it is possible to prevent the portion of the light transmitting member protruding outward from the element in the form of FIG. 6, that is, the outer edge thereof, from causing insufficient light quantity from the light emitting element to easily cause color unevenness in the portion. . However, “substantially the same plane” in the present specification may be substantially the same plane in terms of the functions described above. Further, the light transmission member 15 may be formed by stacking only a part of the light emitting element 10, that is, the side surface 15 c of the light transmission member 15 may be positioned on the inner side of the end surface 33 of the light emitting element 10. By narrowing the light emitting region and making the light emitting surface smaller than that of the light emitting element, the color mixture ratio can be made substantially constant, so that the emitted light can be further reduced in color unevenness. Further, the relative luminance can be increased by reducing the light emitting area. As a form in which the size of such a light source is reduced as compared with the light emitting element and its mounting region, in addition, a structure in which an opening member having a part of the light transmitting member is provided, for example, the sealing member is provided. It can also be set as the structure provided so that a part of light emission surface might cover.

(Embodiment 3)
FIG. 7 is a schematic cross-sectional view of the light emitting device 20 according to the third embodiment. In the third embodiment, as compared with the second embodiment, the sealing member 26b covers only the outer side on the end face 33 side of the light emitting element 10, and on the surface of the light emitting element, the sealing member 26b is optically connected to the light transmitting member. The exposed portions exposed from the connecting portions to be connected and the electrical and physical connecting portions to the substrate are separated without being covered and are not filled in the mutually separated regions of the plurality of light-emitting elements 10 mounted thereon. A void is formed. Specifically, the sealing member 26b is positioned on the end face 33 side of the light emitting element 10 so as to be substantially parallel to and spaced from the end face 33. That is, the light emitting element 10 is vertically moved by the light transmitting member 15 and the wiring substrate 9. The left and right directions are surrounded by a sealing member 26b. At this time, the light receiving surface and a part of the light emitting element may be covered with the sealing member and separated from the remaining part. An internal space with each surrounding member as a boundary is formed, and a cavity is provided in the vicinity of the periphery of the light emitting element 10. In this way, the covering member is formed as an area on the light receiving surface side of the light transmitting member, an enclosure surrounding the light emitting element, and an internal area formed by being separated from the light emitting element inside the enclosure. It is preferable to provide. At this time, as shown in the figure, the enclosure is formed as a light transmissive member as the window portion of the enclosure, an outer casing provided with the light emitting surface, and an outer casing provided with the light emitting surface on the front surface in the emission direction. It is preferable. Thereby, light is reflected at the interface between the light transmitting member (light receiving surface), the light emitting element and the cavity of the internal space, and the loss due to light absorption of the sealing member can be reduced. At this time, it is preferable to form the exposed portion of the element and the air / gas by airtight sealing or the like so as to increase the difference in refractive index at the interface. In addition, when a plurality of light emitting elements are optically connected to one light transmitting member, it is preferable that gaps are similarly formed between the elements. This includes an optical connection region with the element and a filling member connection region connected to the light transmission member filled in the internal space on the light receiving surface of the light transmission member, and the light emission from the element is directly optical. In addition to the path of light entering the connection area, the light is taken out by the filling member and incident from the filling member connection area, whereby a light emitting surface larger than the element can be formed. In addition, since the shape of the sealing member 26b is simple, the light emitting device 20 can be obtained by separately manufacturing the sealing member 26b and connecting it to the light transmitting member 15 side. Further, in the light emitting device having the separation region, the light reflecting member is additionally provided so as to surround the separation region so as to reflect the light in the region, and can be configured to reflect on the surface, for example, It can also be provided as a coating layer on the wiring board.

(Embodiment 4)
The wavelength conversion sintered body 500 of the first embodiment can be applied as the light transmitting member 15. FIG. 8 is a schematic cross-sectional view of the light emitting device 30 according to the fourth embodiment. The light emitting device 30 includes a light emitting element 10, a mounting base 301 provided with a recess (cavity) 302 that accommodates the light emitting element 10, and provided with lead electrodes 303 a and 303 b, and is fitted above the concave part 302 of the mounting base 301. And a light transmitting member 15 fixed in place. The light emitting element 10 is mounted face-up on the bottom surface of the recess 302 of the mounting substrate 301 using a bonding member 304, and the positive and negative electrodes (not shown) of the light emitting element 10 and the lead electrodes 303a and 303b are electrically connected. Wire connection is made using members. In the light emitting device 30, since the light emitting element 10 and the light transmitting member 15 can be the same as those described in the first to third embodiments, detailed description thereof is omitted. Below, each other member and structure of the light-emitting device 30 in this invention are demonstrated.

(Mounting substrate)
The mounting substrate 301 is a support having lead electrodes 303a and 303b on which the light emitting element 10 is placed in the recess 302 and can be electrically connected to the outside. A member having insulating properties, excellent thermal conductivity, a low thermal expansion coefficient, and a member that hardly transmits light from a semiconductor light emitting element or external light is preferable. In addition, you may have a some recessed part and opening part according to the number and magnitude | size of the light emitting element 10. FIG. The bonding member 304 is an adhesive for mounting the light emitting element 10 on the mounting substrate 301 or the lead electrodes 303a and 303b, and can be selected to be conductive or insulating depending on the substrate of the light emitting element 10 to be mounted. For example, in the case of an insulating substrate, the bonding member 304 can be either insulating or conductive. In the case of a conductive substrate such as an n-type GaN substrate, the conductive member is mounted on the lead electrode using a conductive member to conduct. Can be made. Furthermore, when the joining member 304 is translucent, a wavelength conversion member can be included in the bonding member 304 and light can be converted.

  The concave portion 302 includes a bottom surface and a side surface having a flat tapered surface (inclined surface) that rises from the outer peripheral edge of the bottom surface to the upper opening and expands outward toward the opening side, and efficiently uses the light from the light emitting element 10. It has a structure that reflects well. Further, a reflective layer of a metal film such as Ag or Al may be provided on the inner surface of the recess 302. As in the third embodiment, air or gas may exist in the inner space of the recess 302 by airtight sealing or the like. On the other hand, after the light emitting element 10 is mounted on the bottom surface of the recess 302, a resin or the like is placed in the recess 302. A covering member (sealing member) may be filled. Moreover, a coloring agent, a light diffusing agent, a filler, a wavelength conversion member, etc. can also be contained in the coating member as desired. The lead electrodes 303a and 303b are the same as the wiring structure of the wiring board of the second and third embodiments, and are used to supply power to the light emitting element 10 from the outside of the mounting substrate 301. For this reason, various types such as a conductive pattern provided on the mounting substrate 301 and a lead frame are used.

  As in the present embodiment, as long as the light transmitting member 15, that is, the wavelength conversion sintered body 500 and the light emitting element 10 are optically connected, they may be physically separated from each other. For example, the mounting substrate may be a lead frame or a stem in which the mounting substrate and the lead electrode are integrated, and the light emitting element 10 is an LD, and wavelength conversion is performed on a cap window or the like. It is also possible to provide a light emitting device in which the sintered body 500 is arranged and irradiated with laser light, and the mixed color light is scattered by the wavelength conversion sintered body 500 and extracted outside.

(Comparative Examples 1 to 3 and Example 4)
About the light-emitting device in Embodiment 2, using the light-conversion sintered body of Embodiment 1 for a light transmissive member, each light-emitting device of the following comparative examples and examples is produced, and the light distribution relating to light distribution and luminance Confirm the superiority of the characteristics. Comparative Examples 1 to 3 and Example 4 differ only in the light transmitting member, and the other structures are the same. Specifically, the light-transmitting member of Comparative Example 1 is not subjected to uneven processing on the surface, whereas in Example 4, the wavelength conversion sintered body 500 provided with the surface layer subjected to the uneven processing on both opposing surfaces. Adopted. Moreover, the light transmission member of Comparative Example 2 and Comparative Example 3 was not a sintered body of material components, but formed a phosphor layer by a printing method.

More specifically, the light-emitting device of Example 4 has one light transmitting member 15 and two approximately square LED chips (emission wavelength 455 nm) of about 1 mm × 1 mm as shown in FIG. The light transmissive member 15 and a part of the light emitting element 10 are covered with the sealing member 26. The light transmitting member 15 is sliced from a sintered body having a YAG (center wavelength of 577 nm) concentration of 20% to form a plate-like YAG sintered plate, and both surfaces of the YAG sintered plate are polished, and phosphoric acid sulfate is applied to both surfaces. Etch with the solution at 300 ° C. for 5 minutes. The YAG sintered plate is cut out by dicing, and the light-emitting surface 15a of the wavelength conversion sintered body and the light-receiving surface 15b facing the light-emitting surface 15a have a rectangular shape composed of about 1.1 mm × 2.2 mm. The thickness is 116 μm. Further, the sealing member 26 is a silicone resin containing TiO ₂ particles, and as shown in FIG. 5, in a plan view on the light extraction side of the light emitting device 1, a peripheral region of the light emitting surface 15a, specifically, The light transmitting member 15 is formed so as to cover the side surface 15c and to follow the surface shape of the light emitting surface 15a. That is, the light-emitting device 1 uses the light-emitting surface 15a as the main light-emitting surface and covers the periphery thereof with the sealing member 26, thereby suppressing light emission from the covered region to the outside. Further, the light transmitting member 15 covers the optical connection region with the light emitting element 10 on the light receiving surface 15b, and further fills the space between the wiring board 9 and the light transmitting member 15 to thereby form the side surface of the light emitting element 10. And the mounting side is also covered.

  On the other hand, the light transmissive member of Comparative Example 1 is a YAG sintered plate obtained by slicing the same sintered body as in Example 4. However, the etching process after polishing is omitted, the thickness is 120 μm, and the other dimensions are the same. The light transmissive member. Further, in the light emitting devices of Comparative Example 2 and Comparative Example 3, a YAG phosphor layer is formed by a printing method around the LED (face and surface) mounted face down, and Comparative Example 2 has an average particle size of about 11 μm. YAG is used, and Comparative Example 3 uses YAG having an average particle diameter of 5 μm. In each of the light emitting devices of Comparative Examples 1 to 3 and Example 4, the light distribution characteristics emitted from two directions orthogonal to the center of the light emitting surface 15a, that is, from the horizontal plane side and the vertical plane side will be compared. Specifically, as shown in FIG. 9A, the longitudinal direction of the light emitting surface is 90 °, the direction orthogonal to this is 0 °, and the graphs of the respective light distribution characteristics are shown in FIGS. 9B and 9C. ) Respectively.

  9 (b) and 9 (c), the light emitting device having the double-sided YAG sintered plate in Example 4 has the least chromaticity unevenness in the light distribution from two directions, and the end from the center of the light emitting surface. The chromaticity is substantially constant over the part. In the light emitting devices of Comparative Examples 1 to 3 that are not subjected to uneven processing, the tendency that the phosphor color becomes stronger as the angle is higher is emphasized. Further, in the light transmitting member by the printing method, the degree of color unevenness depending on the observation direction. Is significantly different. That is, in the comparative example, the secondary light condensed in the high angle region is distributed in the peripheral region of the light emitting surface and induces color unevenness with the central region, so the light emitting region corresponding to this high angle is removed, Alternatively, there is a need to avoid color unevenness of the entire light by mounting another member such as a diffusion sheet, leading to a reduction in output or a complicated apparatus. On the other hand, in the light emitting device of Example 4, the light dispersion effect due to the uneven surface is remarkably exhibited, and good light distribution characteristics are provided over almost the entire light emitting surface. Therefore, light loss due to partial removal of the light emitting surface can be avoided and relatively high output and high luminance can be achieved.

  In addition, the luminance of the light emitting surface according to Comparative Example 1 (no processing) and Example 4 (double-side processing), and observation of chromaticity (x value, y value) in accordance with the International Lighting Commission (CIE) xyz color system. The results are shown in FIG. 10 (Comparative Example 1 is FIG. 10A and Example 4 is FIG. 10B). FIG. 10 shows that the contrast is displayed low in Example 4, that is, light emission with reduced luminance unevenness is realized over substantially the entire light emitting surface by double-sided processing. In particular, in Comparative Example 1, the light is condensed immediately above each LED arranged in parallel in the central area of the light emitting surface, and the luminance is low and the color unevenness is remarkable in a region separated from the optical axis from the LED. On the other hand, in the fourth embodiment, this is avoided, and the light is sufficiently diffused so that the arrangement area of the light source cannot be recognized, and the luminance and hue are constant over substantially the entire area of the light emitting surface. That is, the processed surface exhibits excellent diffusibility, and brightness unevenness and color unevenness can be reduced in the light distribution without having a separate diffusion member.

(Example Aa to Example Cd)
Next, the luminous flux of the emitted light by the difference in the processing state of a YAG sintered plate is compared. Specifically, a light-emitting device similar to that in Example 4 was prepared except that each wavelength-converted sintered body (see FIG. 3) of each condition described in Examples 1 to 3 was mounted. Measure the luminous flux. In addition, the name of the example is expressed as “Example + Pre-etching treatment method (A to C)” in order to represent the combination of each condition of the pre-etching process (A to C) and the etching process (a to e) and the name of the example. C) + etching treatment conditions (ae) ”. For example, only the YAG plate is polished (A) and no etching is performed as Example A. In another example, the YAG plate is polished (A) and then etched at 260 ° C. for 1 minute (a). Is referred to as Example Aa. Moreover, after blasting (B) after forming the sintered body, etching is performed at 300 ° C. for 1.5 minutes (b). FIG. 11 shows the luminous fluxes of the comparative examples and examples.

  Furthermore, the conversion efficiency of the primary light in the light emitting device of each of the above examples was evaluated. Specifically, an LED as a light source is mounted face-down on a package, the output (mW) of the LED is measured, and then a YAG sintered plate of each condition is mounted, and a light emitting device as in Example 4 above And the luminous flux (lm) of the emitted light is measured. Based on these measured values, the luminous flux (lm) of the emitted light is divided by the output (mW) of the LED, and the conversion efficiency from primary light to total light is calculated. The results obtained under each condition are shown in FIG. As shown in FIGS. 11 and 12, a decrease in output due to the presence or absence of surface processing can be substantially avoided. In other words, as described above, since it is possible to emit light with uniform brightness and chromaticity over almost the entire light emitting surface, it is possible to use all the emitted light without any loss of light loss in the subsequent secondary usage, Relatively high brightness unit light can be obtained. Increased versatility.

  Further, in the light emitting devices of Examples Aa to Af in which the pre-etching treatment of the wavelength conversion sintered body 500 is limited to polishing (A) and the etching conditions are a to e, the light distribution color The degree (y value) was compared. The results are shown in the graph of FIG. Further, the light distribution chromaticity y due to the change in the etching conditions when the pre-etching treatment is not performed (C) is examined, and the result is shown in FIG. As shown in FIGS. 13 and 14, the increase in the y value is significant in the high-angle region (both ends on the horizontal axis of the graph) under conditions of only polishing or no pretreatment and no etching. That is, it means the occurrence of color unevenness in the periphery and the center area on the light emitting surface. On the other hand, it can be understood that as the etching time is longer, the increase in the high angle region is suppressed, and the value of the light distribution chromaticity y is substantially uniform and stable over the entire light emitting surface from the high angle region to the low angle region.

  The light emitting device and the manufacturing method thereof of the present invention can be suitably used for illumination light sources, LED displays, backlight light sources, traffic lights, illumination switches, various sensors, various indicators, and the like.

2 is a schematic cross-sectional view of a wavelength conversion sintered body according to Embodiment 1. FIG. 2A is a schematic cross-sectional view related to a conventional wavelength conversion sintered body, and FIG. 2B is a schematic cross-sectional view related to the wavelength conversion sintered body of the first embodiment. It is a comparison table of the surface state concerning each wavelength conversion sintered compact of Example 1 thru / or Example 3. It is a comparative table | surface which shows the difference in the surface state and cross-sectional state of the wavelength conversion sintered compact by processing conditions. 5 is a schematic cross-sectional view of a light emitting device according to Embodiment 2. FIG. 4 is a schematic cross-sectional view of a light emitting device according to Embodiment 2. FIG. 6 is a schematic cross-sectional view of a light emitting device according to Embodiment 3. FIG. 6 is a schematic diagram of a light emitting device according to Embodiment 4. FIG. The light distribution characteristic of a comparative example and an Example is shown. The brightness | luminance characteristic of a comparative example and an Example is shown. It is a graph which shows the light beam of an Example. The conversion efficiency of an Example is shown. The light distribution chromaticity y of an Example is shown. The light distribution chromaticity y of an Example is shown. It is sectional drawing which shows the conventional semiconductor light-emitting device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 20, 30 ... Light-emitting device 2 ... Light reflective member 3A ... 1st electrode (n-type pad electrode)
3B ... Second electrode (p-type pad electrode)
4 ... Electrode surface 5 ... Growth substrate (sapphire substrate)
6: First nitride semiconductor layer (n-type semiconductor layer)
7: Second nitride semiconductor layer (p-type semiconductor layer)
8 ... Light emitting layer (active layer)
9 ... Wiring board (submount)
DESCRIPTION OF SYMBOLS 10 ... Light emitting element 11 ... Semiconductor structure 12 ... Phosphor particle 13 ... Translucent conductive layer (Translucent electrode, ITO)
DESCRIPTION OF SYMBOLS 14 ... Protective film 15 ... Light transmissive member 15a ... Light-emitting surface 15b ... Light-receiving surface 15c ... Side surface 17 ... Adhesive (silicone resin)
24 ... Conductive member 26, 26b ... Cover member (sealing member, resin)
33 ... End face 301 ... Mounting substrate 302 ... Recess (cavity)
303a, 303b ... lead electrode 304 ... bonding member 500, 600 ... wavelength conversion sintered body 501, 601 ... first main surface (light emitting surface)
502, 602... Second main surface (light receiving surface)
DESCRIPTION OF SYMBOLS 503 ... Recessed part 504 ... Inorganic particle 505 ... Surface layer 506 ... Center layer 801 ... Light-emitting device 802 ... Incident surface 803 ... Light emitting surface 805 ... LED
807 ... Fluorescent screen d1, d2 ... Depth L ... First light

Claims (10)

A first step of mixing and sintering inorganic powder and phosphor powder to obtain a sintered body;
Etching the sintered body to form a plurality of recesses on the surface of the sintered body;
Including
In the second step, the sintered body is etched at 260 ° C. or higher so that the phosphor particles in the sintered body are preferentially dissolved over the inorganic particles in the sintered body, and the sintering is performed. Etching so that the inorganic substance on the surface of a bonded body is granulated , The manufacturing method of the wavelength conversion sintered compact characterized by the above-mentioned.   The method for producing a wavelength conversion sintered body according to claim 1, wherein the etching is wet etching. Method of manufacturing a wavelength converter sintered body according to claim 2 wherein the inorganic material is characterized by Oh Rukoto in Al ₂ O _3.   The method for producing a wavelength conversion sintered body according to any one of claims 1 to 3, further comprising a third step of polishing the sintered body before the second step.   The method for producing a wavelength conversion sintered body according to any one of claims 1 to 4, wherein the concave portion has an irregular shape.   The method for producing a wavelength conversion sintered body according to claim 3, wherein the recess has a shape in which phosphor particles in the sintered body are dissolved. A wavelength conversion sintered body which is a sintered body of an inorganic substance and a phosphor and has a plate-like shape having first and second main surfaces,
The wavelength conversion sintered body is:
A surface layer provided with a plurality of recesses on at least the first main surface;
A central layer inside the surface layer;
Have
The phosphor particles contained in the wavelength conversion sintered body are distributed more in the central layer than in the surface layer,
A wavelength conversion sintered body having an inorganic material granulated on the surface layer. The wavelength conversion sintered body according to claim 7,
A light emitting element;
A light emitting device comprising:
The light-emitting device, wherein the first main surface is a light-receiving surface that receives light emitted from the light-emitting element or a light-emitting surface that emits the received light. The second main surface is a smooth surface with the central layer exposed,
The light emitting element is disposed on the second main surface side,
The light emitting device according to claim 8, wherein the first main surface is the light emitting surface. A plurality of light emitting elements are arranged on the second main surface side of one wavelength conversion sintered body,
The light emitting device according to claim 8, wherein the first main surface is the light emitting surface.