JP2020080431A - Light-emitting device and method for manufacturing the same - Google Patents

Abstract

To provide a light-emitting device which enables the enhancement in light output and color rendering properties.SOLUTION: A light-emitting device 100 comprises: a package 2 as a base; a light-emitting element 1 disposed in the package 2; a first wavelength conversion member 3 covering a side face of the light-emitting element 1, and including a first phosphor for converting light emitted by the light-emitting element 1 into light of a light emission peak wavelength longer than a light emission peak wavelength of the light-emitting element 1; and a second wavelength conversion member 4 covering a top face of the light-emitting element 1 and the package 2, and including a second phosphor for converting light emitted by the light-emitting element 1 into light of a light emission peak wavelength which is longer than the light emission peak wavelength of the light-emitting element 1 and shorter than the light emission peak wavelength of the first phosphor. In a part of the second wavelength conversion member 4, covering the package 2, a concentration of the second phosphor at the height of the top face of the light-emitting element 1 is smaller than a concentration of the second phosphor at the height of a bottom face of the light-emitting element 1. The second phosphor reflects light of the light emission peak wavelength of the first phosphor.SELECTED DRAWING: Figure 1C

Description

  The present disclosure relates to a light emitting device and a manufacturing method thereof.

  A light emitting device using a semiconductor light emitting element such as an LED (light emitting diode) is widely used in the market such as a backlight, an illumination, and a vehicle light. Further, a light emitting device using a blue LED and a plurality of types of phosphors such as a green to yellow phosphor and a red phosphor has been proposed in order to output white light having high color rendering properties. Generally, multiple types of phosphors are mixed with encapsulating resin and applied to the surface of the LED. However, when multiple types of phosphors are mixed and used, the yellow-green phosphor with a large specific gravity and large particle size comes first. Since it sinks, the light from the yellow-green phosphor is easily absorbed by the red phosphor. The red phosphor is excited by the light from the yellow-green phosphor and emits red light, but since it is a two-stage excitation, the wavelength conversion efficiency is low when viewed from the blue light from the blue LED, and the white light source is used. As a result, the output will decrease.

For example, Patent Documents 1 to 5 propose light emitting devices using a blue LED and a plurality of types of phosphors such as a green phosphor and a red phosphor. In these patent documents, a red phosphor layer and a green phosphor layer are arranged in this order toward the outside where light is extracted from the blue LED side, and green light from the green phosphor is absorbed by the red phosphor. A light-emitting device having a difficult structure has been proposed.
Further, for example, Patent Document 6 proposes a light emitting device capable of increasing the light output from the upper surface side and the side surface side by providing a light reflecting film on the lower surface side of the LED.

JP, 2007-184330, A JP, 2007-184326, A JP, 2009-182241, A JP, 2005-228996, A JP, 2004-71726, A JP, 2011-243977, A

  However, in the light emitting devices described in Patent Documents 1 to 5, there is room for improvement in both light output and color rendering. Further, in the light emitting device described in Patent Document 6, if a plurality of types of phosphors are mixedly arranged, there is a limit to the improvement of the output of the light emitting device.

  An object of an embodiment according to the present disclosure is to provide a light emitting device capable of enhancing light output and color rendering.

  The light emitting device according to the embodiment of the present disclosure covers a base, a light emitting element arranged on the base, a side surface of the light emitting element, and emits light emitted by the light emitting element from an emission peak wavelength of the light emitting element. A first wavelength conversion member containing a first phosphor that converts light having a longer emission peak wavelength, and the light emitted from the light emitting element, which covers the upper surface of the light emitting element and the base, and emits light emitted from the light emitting element. A second wavelength conversion member containing a second phosphor that is longer than a wavelength and that converts light having an emission peak wavelength shorter than the emission peak wavelength of the first phosphor, the second wavelength conversion member, In the portion covering the base, the first concentration, which is the concentration of the second phosphor at the height of the upper surface of the light emitting element, is the concentration of the second phosphor at the height of the lower surface of the light emitting element. The concentration is lower than 2 and the second phosphor is configured to reflect light having the emission peak wavelength of the first phosphor.

  Further, a light emitting device according to an embodiment of the present disclosure in another aspect, a base, a light emitting element arranged on the base, a side surface of the light emitting element is covered, and light emitted by the light emitting element is emitted by the light emitting element. A first wavelength conversion member containing a first phosphor that converts light having an emission peak wavelength longer than the emission peak wavelength of the element, and covering the upper surface and the base of the light emitting element, the light emitted by the light emitting element, A second wavelength conversion member containing a second phosphor that is longer than the emission peak wavelength of the light emitting element and is converted into light having an emission peak wavelength shorter than the emission peak wavelength of the first phosphor, In the cross section of the two-wavelength conversion member cut from the upper surface to the lower surface, the cross section of the second phosphor occupies a height from half the height of the light emitting element to the upper surface of the light emitting element. The first area ratio, which is the ratio of the area, is the ratio of the area occupied by the cross section of the second phosphor at a height that is half the height of the light emitting element from the upper surface of the base. It is configured to be smaller than.

  Further, a light emitting device according to an embodiment of the present disclosure in still another aspect, a base, a light emitting element arranged on the base, and a side surface of the light emitting element is covered, and light emitted by the light emitting element is A first wavelength conversion member containing a first phosphor that converts light having an emission peak wavelength longer than the emission peak wavelength of the light emitting element, and an upper surface of the light emitting element and the base to cover light emitted by the light emitting element. A second wavelength conversion member containing a second phosphor that is longer than the emission peak wavelength of the light emitting element and is converted into light having an emission peak wavelength shorter than the emission peak wavelength of the first phosphor, In the second wavelength conversion member, the second phosphor is arranged in layers at least in a portion arranged on the base, and the thickness of the layer is not more than 3/4 of the height of the light emitting element. It is configured as follows.

A method for manufacturing a light emitting device according to an embodiment of the present disclosure includes a step of disposing at least one light emitting element on a support member, and a first wavelength conversion member containing a first phosphor on a side surface of the light emitting element. A step of disposing, a step of disposing the light emitting element provided with the first wavelength conversion member on a base, and covering an upper surface and a side surface of the light emitting element provided with the first wavelength conversion member, And a step of disposing a second wavelength conversion member containing a second phosphor in this order.

  According to the light emitting device and the manufacturing method thereof according to the embodiment of the present disclosure, it is possible to improve light output and color rendering.

It is a perspective view which shows the structure of the light-emitting device which concerns on embodiment. It is a top view which shows the structure of the light-emitting device which concerns on embodiment. FIG. 2 is a cross-sectional view showing the configuration of the light emitting device according to the embodiment, showing a cross section taken along the line IC-IC in FIG. 1B. FIG. 3 is a cross-sectional view showing a configuration example of a light emitting element in the light emitting device according to the embodiment. FIG. 6 is a graph showing an emission spectrum and a reflection spectrum of a phosphor example used in the light emitting device according to the embodiment. It is a figure explaining the light extraction in the light-emitting device which concerns on embodiment. It is a figure explaining the light extraction in the light-emitting device which concerns on embodiment, and is an enlarged view of the area|region VIB of FIG. 4A. 6 is a flowchart showing a procedure of a method for manufacturing a light emitting device according to an embodiment. FIG. 6 is a cross-sectional view showing a first light emitting element placement step in a first wavelength conversion member placement step in the method for manufacturing a light emitting device according to the embodiment. FIG. 8 is a cross-sectional view showing a first resin disposing step in the first wavelength converting member disposing step in the method for manufacturing the light emitting device according to the embodiment. In the manufacturing method of the light-emitting device which concerns on embodiment, it is sectional drawing which shows the 1st resin cutting process in a 1st wavelength conversion member arrangement|positioning process. FIG. 6 is a cross-sectional view showing a second light emitting element disposing step in the method for manufacturing the light emitting device according to the embodiment. FIG. 6 is a cross-sectional view showing a second resin disposing step in a second wavelength converting member disposing step in the method for manufacturing the light emitting device according to the embodiment. In the manufacturing method of the light-emitting device which concerns on embodiment, it is sectional drawing which shows the 2nd fluorescent substance sedimentation process in a 2nd wavelength conversion member arrangement|positioning process.

Hereinafter, the light emitting device according to the embodiment and the method for manufacturing the same will be described.
It should be noted that the drawings referred to in the following description are schematic illustrations of the embodiments, and therefore scales, intervals, positional relationships, and the like of each member are exaggerated, or a part of the members is not shown. There are cases. In addition, for example, the scales and intervals of the members may not match in the plan view and the sectional view thereof. Further, in the following description, the same name and reference numeral basically indicate the same or the same member, and detailed description thereof will be appropriately omitted.

  Further, in the light emitting device and the manufacturing method thereof according to the embodiment, “upper”, “lower”, “left”, “right” and the like are interchanged depending on the situation. In this specification, “upper”, “lower” and the like indicate relative positions between constituent elements in the drawings referred to for the description, and indicate absolute positions unless otherwise specified. Not intended.

In addition, in the present specification, the relationship between the color name and the chromaticity coordinate, the relationship between the wavelength range of light and the color name of monochromatic light, and the like are in accordance with Japanese Industrial Standard JIS Z8110 unless otherwise specified. Specifically, in the wavelength range of monochromatic light, 380 nm to 455 nm is blue violet, 455 nm to 485 nm is blue, 485 nm to 495 nm is blue green, 495 nm to 548 nm is green, 548 nm.
.About.573 nm is yellow green, 573 nm to 584 nm is yellow, 584 nm to 610 nm is yellow red, and 610 nm to 780 nm is red.

[Configuration of light emitting device]
The configuration of the light emitting device according to the embodiment will be described with reference to FIGS. 1A to 1C.
FIG. 1A is a perspective view showing a configuration of a light emitting device according to an embodiment. FIG. 1B is a plan view showing the configuration of the light emitting device according to the embodiment. FIG. 1C is a cross-sectional view showing the configuration of the light emitting device according to the embodiment, and shows a cross section taken along the line IC-IC of FIG. 1B.
Note that, in FIGS. 1A and 1B, hatching with dots indicates that the second wavelength conversion member 4 is present in the recess 23a.
Further, in the cross-sectional view shown in FIG. 1C, a part of the wire 5, the protective element 6, and the joining member 72 are not observed because they are located on the front side of the cross-section, but are shown by broken lines for convenience. The same applies to FIGS. 4A and 7 to 8B described later.
In addition, in FIGS. 1A to 1C and FIGS. 6A to 8B described later, the n-side electrode 13 and the p-side electrode 14 of the light emitting element 1 are simplified and only portions corresponding to the external connection portions 13a and 142a of the both electrodes are formed. Illustrated.

The light emitting device 100 according to the present embodiment includes a light emitting element 1 having a substantially square shape in a plan view, a base 2 for mounting the light emitting element 1 and a package 2 having a substantially square shape in a plan view, and emitting light. The first wavelength conversion member 3 that covers the side surface of the element 1 and the second wavelength conversion member 4 that covers the upper surface of the light emitting element 1 and the upper surface and the side surface of the first wavelength conversion member 3 are configured.
The light emitting element 1 is provided in a recess 23a having an opening on the upper surface side of the package 2, and is bonded to the bottom surface 23b of the recess 23a using a translucent bonding member 71. Further, in the light emitting element 1, the n-side electrode 13 and the p-side electrode 14, which are positive and negative pad electrodes, are provided with the corresponding lead electrodes 21 and 22 exposed on the bottom surface 23b of the recess 23a, and the bonding wire 5 respectively. Are electrically connected using.
In addition, the protective element 6 is provided in the recess 23a, and is electrically connected to the lead electrodes 21 and 22 by the conductive joining member 72 and the wire 5. The second wavelength conversion member 4 is provided in the recess 23a and seals the light emitting element 1 and the protection element 6.

Further, the light emitted from the light emitting element 1 is wavelength-converted by the first phosphor contained in the first wavelength conversion member 3, and the other part is contained in the second wavelength conversion member 4. The wavelengths are converted by the two phosphors, and the remaining portions are not converted in wavelength, and the respective lights are mixed and emitted upward from the opening of the recess 23a.
Further, in the light emitting device 100 of the present embodiment, one light emitting element 1 is mounted, but two or more light emitting elements 1 may be mounted.

Here, a configuration example of the light emitting element 1 will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a configuration example of the light emitting element in the light emitting device according to the present embodiment.
In the present embodiment, since the light emitting device 100 is a top-view type, the main surface of the substrate 11 is parallel to the bottom surface 23b of the recess 23a, which is the surface facing the upper surface side of the light emitting device 100. The light emitting element 1 is mounted.

  As the light emitting element 1, a semiconductor light emitting element such as an LED can be preferably used. The light emitting element 1 according to the present embodiment is formed in a substantially square shape in a plan view, and includes a substrate 11, a semiconductor laminated body 12, an n-side electrode 13, a p-side electrode 14, a protective film 15, and a light reflection film 16. , And are configured. In addition, the light emitting element 1 according to the present embodiment includes a semiconductor laminated body 12 having an LED (light emitting diode) structure on one main surface of the substrate 11, and further has an n-side electrode on one surface side of the semiconductor laminated body 12. It has the structure 13 and the p-side electrode 14, and has a structure suitable for face-up type mounting.

The substrate 11 supports the semiconductor laminated body 12. Further, the substrate 11 may be a growth substrate for epitaxially growing the semiconductor laminated body 12. As the substrate 11, for example, when a nitride semiconductor is used for the semiconductor laminated body 12, a sapphire (Al ₂ O ₃ ) substrate can be used.

  The semiconductor laminated body 12 is formed by laminating an n-type semiconductor layer 12n and a p-type semiconductor layer 12p on one main surface of the substrate 11, and by supplying a current between the n-side electrode 13 and the p-side electrode 14, It emits light. The semiconductor stacked body 12 preferably includes an active layer 12a between the n-type semiconductor layer 12n and the p-type semiconductor layer 12p.

In the semiconductor stacked body 12, a region 12 where the p-type semiconductor layer 12p and the active layer 12a are not partially present, that is, a step portion 12b recessed from the surface of the p-type semiconductor layer 12p is formed. The bottom surface of the step portion 12b is composed of the n-type semiconductor layer 12n. An n-side electrode 13 is provided on the bottom surface of the step portion 12b and is electrically connected to the n-type semiconductor layer 12n.
Further, a step portion 12c where the p-type semiconductor layer 12p and the active layer 12a do not exist is also formed on the outer edge portion of the light emitting element 1. The step portion 12c is a dicing street which is a cutting area when the wafer is diced.

The semiconductor laminated body 12 is preferably formed by laminating semiconductors on a substrate by a liquid phase growth method, a MOCVD method or the like. As the semiconductor material, various emission wavelengths from ultraviolet light to infrared light can be selected by selecting the mixed crystallinity. Therefore, In _X Al _Y Ga _1-XY N (0≦X, 0≦Y, X+Y The gallium nitride based semiconductor represented by <1) can be more preferably used.

The n-side electrode 13 is provided on the bottom surface of the step portion 12b of the semiconductor stacked body 12 so as to be electrically connected to the n-type semiconductor layer 12n, and is on the negative electrode side for supplying the light emitting element 1 with an external current. Of the electrode. Further, the n-side electrode 13 has an external connection portion 13a at a corner of the light emitting element 1 in plan view.
The n-side electrode 13 may be made of, for example, Cu, Au, or an alloy containing any of these metals as a main component so as to be suitable for connection to the outside by wire bonding or the like.

  The p-side electrode 14 is provided on the upper surface of the p-type semiconductor layer 12p so as to be electrically connected to the p-type semiconductor layer 12p, and is an electrode on the positive electrode side for supplying an external current to the light emitting element 1. is there. Further, the p-side electrode 14 has a structure in which a translucent electrode 141 and a pad electrode 142 are laminated.

The lower transparent electrode 141 is provided so as to cover substantially the entire upper surface of the p-type semiconductor layer 12p. The transparent electrode 141 functions as a current diffusion layer for diffusing a current supplied from the outside via the pad electrode 142 over the entire surface of the p-type semiconductor layer 12p. The translucent electrode 141 can be formed using a conductive metal oxide, and particularly ITO (Sn-doped In ₂ O ₃ ) has high translucency in visible light (visible region) and has conductivity. It is preferable because it is a material having a high

The pad electrode 142 on the upper layer side is a layer provided on a part of the upper surface of the translucent electrode 141 for connecting to an external electrode. The pad electrode 142 is composed of an external connecting portion 142a for connecting to the outside by wire bonding or the like, and an extending portion 142b extending from the external connecting portion 142a. The extending portion 142b is arranged so that the current can be diffused more efficiently. As with the n-side electrode 13, the pad electrode 142 is made of, for example, Cu, Au, or an alloy containing any of these metals as a main component so as to be suitable for connection to the outside by wire bonding or the like. it can.
In the present embodiment, the pad electrode 142 has the external connection portion 142a and the extension portion 142b both made of the same material.

The protective film 15 is a film that has a light-transmitting property and an insulating property, and covers substantially the entire top surface and side surfaces of the light emitting element 1 except the side surfaces and the bottom surface of the substrate 11. The protective film 15 has an opening 15n on the upper surface of the n-side electrode 13 and an opening 15p on the upper surface of the pad electrode 142 of the p-side electrode 14. The regions exposed from the openings 15n and 15p are the external connection portions 13a and 142a.
As the protective film 15, for example, oxides such as SiO ₂ , TiO ₂ , and Al ₂ O ₃ , nitrides such as SiN, and fluorides such as MgF can be preferably used.

The light reflection film 16 is provided on the lower surface side of the substrate 11, which is the surface opposite to the light extraction surface of the light emitting element 1. As the light reflection film 16, it is preferable to use a distributed Bragg reflector (DBR) film in which two or more kinds of dielectrics having different refractive indexes are laminated. The dielectric used for the DBR film may be, for example, a combination of SiO ₂ and Nb ₂ O ₅ .
When a DBR film is used as the light reflection film 16, the film thickness of each layer of the dielectric multilayer film is determined so that the center of the wavelength range in which light is highly reflected is the emission peak wavelength of the light emitting element 1. It is preferable. Thereby, the light emitted from the light emitting element 1 can be introduced into the first wavelength converting member 3 provided on the upper surface of the light emitting element 1 or the second wavelength converting member 4 provided on the side surface of the light emitting element 1. .

Here, a case where the light emitting element 1 emits blue light and the first phosphor contained in the first wavelength conversion member 3 emits red light will be described. When the DBR film which is the light reflecting film 16 is designed so that the center of the wavelength range exhibiting a high light reflectance is the emission peak wavelength of the light emitting element 1, the light reflecting film 16 is a red light from the first phosphor. It becomes the characteristic that penetrates most of the.
Therefore, of the light whose wavelength is converted by the first phosphor, the light propagating downward passes through the light reflecting film 16 and enters the translucent bonding member 71.

  The outer shape of the light emitting element 1 in plan view is not limited to a square, and may be a polygon such as a rectangle, a triangle, or a hexagon, or a circle or an ellipse. Further, in the light emitting element 1, the disposition region and shape of the n-side electrode 13 and the p-side electrode 14, the layer structure, and the disposition region and shape of the stepped portion 12b are not limited to the present embodiment, and may be appropriately selected. Can be set.

1A to 1C, the description of the configuration of the light emitting device 100 will be continued.
The package (base) 2 includes lead electrodes 21 and 22 and a resin portion 23. The package 2 has a substantially square outer shape in a plan view, and has a substantially quadrangular prism shape formed flat in the thickness direction of the light emitting device 100. The package 2 has an opening of a concave portion 23a for mounting the light emitting element 1 on the upper surface, and is configured to emit light from the opening, and is suitable for a top view type mounting.

  The lead electrode 21 and the lead electrode 22 are a pair of electrodes corresponding to positive and negative polarities. The lead electrodes 21 and 22 are provided so as to be supported by the resin portion 23, and the upper surfaces of the lead electrode 21 and the lead electrode 22 are spaced apart from each other and are exposed on the bottom surface 23b of the recess 23a. There is.

  In addition, the lead electrodes 21 and 22 are exposed on the lower surface of the package 2 and serve as a mounting surface of the light emitting device 100 for connecting to the outside. Therefore, the light emitting device 100 is mounted by causing the bottom surface to face the mounting substrate and bonding the lower surfaces of the lead electrodes 21 and 22 to the wiring pattern of the mounting substrate using a conductive bonding member such as solder.

The lead electrodes 21 and 22 are formed using a plate-shaped metal and may have a uniform thickness, or may be partially thickened or thinned.
The material forming the lead electrodes 21 and 22 is not particularly limited, but a material having a relatively large thermal conductivity, a material having a relatively large mechanical strength, or a material that can be easily subjected to punching press processing or etching processing is preferable. Specific examples include metals such as copper, aluminum, gold, silver, tungsten, iron and nickel, iron-nickel alloys and alloys such as phosphor bronze. In addition, in order to efficiently extract light from the mounted light emitting element 1, the first wavelength conversion member 3, and the second wavelength conversion member 4 on the surface of the inner lead portions 21a and 22a exposed on the bottom surface 23b of the recess 23a. It is preferable that reflective plating such as Ag having good light reflectivity is applied.

  The resin portion 23 is a base body of the package 2 for supporting the lead electrodes 21 and 22. The resin portion 23 has a concave portion 23a having an opening on the upper surface side, and the lead electrodes 21 and 22 are configured to be exposed on the bottom surface 23b of the concave portion 23a so as to be separated from each other. Further, the lead electrodes 21 and 22 are exposed on the lower surface side of the resin portion 23 to form a mounting surface.

One light emitting element 1 and one protective element 6 are mounted on the lead electrodes 21 and 22 which are the bottom surface 23b of the recess 23a. The inner side surface of the recess 23a is an inclined surface that is inclined so as to spread upward, and is configured to reflect light emitted laterally from the light emitting element 1 in the upward direction which is the light extraction direction.
Further, one corner of the recess 23a, which is substantially square in a plan view, is formed into a chamfered shape and serves as a cathode mark 23c for identifying the polarities of the lead electrodes 21 and 22.

The resin portion 23 is formed of a material having light reflectivity by containing particles of a light reflecting substance in a resin having a light transmitting property, and reflects the light from the light emitting element 1 in the recess 23a, It also functions as a light reflection member for efficiently emitting light upward.
Further, the translucent second wavelength conversion member 4 is filled in the recess 23a.

  As a resin material used for the resin portion 23, it is preferable that the resin material has a good light-transmitting property with respect to the wavelength of light emitted from the light emitting element 1, and a thermosetting resin or a thermoplastic resin can be used. For example, as the thermosetting resin, a silicone resin, a silicone modified resin, a silicone hybrid resin, an epoxy resin, an epoxy modified resin, a urea resin, a diallyl phthalate resin, a phenol resin, an unsaturated polyester resin, or a hybrid containing one or more of these resins. Resin etc. are mentioned.

  As the light-reflecting substance contained in the resin portion 23, it is preferable to use particles of a material having a large refractive index difference with the above-mentioned resin material and having a good light-transmitting property. Such a light-reflecting substance preferably has a refractive index of, for example, 1.8 or more, and a refractive index difference with the resin material is, for example, 0.4 or more. The average particle size of the light-reflecting substance particles is preferably 0.08 μm or more and 10 μm or less so that the light scattering effect can be obtained with high efficiency.

  Unless otherwise specified, the value of the particle size of the particles such as the light-reflecting substance and the phosphor is the average particle size according to the air permeation method or Fisher Sub-Sieve Sizers.

Further, as the light reflecting substance, specifically, particles of a white pigment such as TiO ₂ (titanium oxide) or Al ₂ O ₃ (aluminum oxide) can be used. Among them, TiO ₂ is preferable because it is relatively stable to moisture and has a high refractive index and has excellent thermal conductivity.

  In addition, the resin material contains a light-reflecting substance in a range where sufficient light reflectivity is obtained and moldability in forming the shape of the package is not impaired. For that purpose, the content of the light-reflecting substance contained in the resin portion 23 is preferably 10% by mass or more and 60% by mass or less.

The first wavelength conversion member 3 is provided so as to cover the side surface of the light emitting element 1, and converts a part of the light emitted by the light emitting element 1 into light of a different wavelength. Therefore, the first wavelength conversion member contains particles of the first phosphor that is a wavelength conversion substance that converts the light emitted by the light emitting element 1 into light having an emission peak wavelength longer than the emission peak wavelength of the light emitting element 1. is doing.
The first wavelength conversion member 3 can be formed using a translucent resin material containing particles of the first phosphor. As the resin material, the same material as that used for the resin portion 23 of the package 2 can be used.

  The first wavelength conversion member 3 is provided so as to cover the entire side surface of the light emitting element 1, but is not provided on the upper surface of the light emitting element 1. Therefore, the second conversion member 4 is provided on the upper surface of the light emitting element 1 so as to be in contact with the light emitting element 1.

The second wavelength conversion member 4 is provided in the recess 23 a of the package 2 as the base so as to cover the upper surface of the light emitting element 1 and the upper surface and the side surface of the first wavelength conversion member 3, and A part of the light is converted into light of a different wavelength. Therefore, the second wavelength conversion member 4 converts the light emitted by the light emitting element 1 into light having an emission peak wavelength longer than the emission peak wavelength of the light emitting element 1 and shorter than the emission peak wavelength of the first phosphor. It contains particles of a second phosphor which is a wavelength conversion substance.
In addition, in the present embodiment, the second wavelength conversion member 4 is also a sealing member that seals the light emitting element 1, the first wavelength conversion member 3, the protection element 6, the wire 5, and the like.

The second wavelength conversion member 4 contains the second phosphor in a relatively high concentration on the bottom surface 23b side of the recess 23a, that is, in the vicinity of the bottom surface 23b and in the vicinity of the upper surfaces of the light emitting element 1 and the first wavelength conversion member 3. Has a high concentration region 4a.
The first concentration, which is the concentration of the second phosphor at the height of the upper surface of the light emitting element 1, is the height of the lower surface of the light emitting element 1, that is, the second concentration which is the concentration of the second phosphor in the high-concentration region 4a. It is preferable to dispose the particles of the second phosphor so that the number of particles is one-tenth or less. In particular, the first concentration is more preferably 2/5 or less of the second concentration. In other words, in the second wavelength conversion member 4, the second phosphors are unevenly distributed on the bottom surface 23b side, and the second phosphors are arranged substantially in layers. Thereby, the ratio of the light from the first wavelength conversion member 3 blocked by the second wavelength conversion member 4 can be reduced, and the light from the first wavelength conversion member 3 can be laterally emitted.

  In addition, the layered high-concentration region 4a is preferably provided so that the upper end thereof has a height not more than 3/4 of the height of the first wavelength conversion member 3, and preferably not more than ⅔. It is more preferable to provide. In other words, the second phosphor is substantially not arranged in a region of a quarter or more of the upper layer portion of the outer surface of the first wavelength conversion member 3, and more preferably in a region of one third or more. Preferably.

As described above, by providing a region not containing the second phosphor or a region having a low concentration of the second phosphor in the upper layer portion of the outer surface of the first wavelength conversion member 3 provided on the side surface of the light emitting element 1. The light emitted by the first phosphor contained in the first wavelength conversion member 3 can be easily taken out to the outside without being reflected or absorbed by the second phosphor.
In addition, the second fluorescent material is unevenly distributed in the vicinity of the light emitting element 1 or the lead electrodes 21 and 22 having higher thermal conductivity than the resin that is the base material of the second wavelength conversion member 4, so that the second fluorescent material is generated. The heat generated by the Stokes loss generated by the body can be efficiently radiated to the outside.

  The region where the concentration of the second phosphor is low may be, for example, a region where the concentration of the second phosphor at the height of the lower surface of the light emitting element 1 is ½ or less. The high-concentration region 4a can be a region having a concentration higher than half the concentration of the second phosphor at the height of the lower surface of the light emitting element 1.

Further, the arrangement of the second phosphor can be defined by the area ratio of the cross section of the particles of the second phosphor in the cross section of the second wavelength conversion member 4, instead of the above-mentioned definition by the concentration.
Specifically, in the cross section of the second wavelength conversion member 5 cut from the upper surface to the lower surface, the second wavelength at a height from half the height of the light emitting element 1 to the upper surface of the light emitting element 1 The first area ratio, which is the ratio of the area occupied by the cross section of the phosphor, is the area occupied by the cross section of the second phosphor at a height half the height of the light emitting element 1 from the upper surface of the package 2 which is the base. Can be set to be smaller than the second area ratio, which is the ratio of

  Here, the area of the cross section of the second wavelength conversion member 4 which is referred to when determining the first area ratio and the second area ratio may be the entire band-shaped area corresponding to the above-described height range corresponding to each. it can. That is, the first area ratio and the second area ratio are determined by the ratio of the area occupied by the cross section of the second phosphor in the entire area of the corresponding height range in the cross section of the second wavelength conversion member 4. By making the reference region the entire region of the corresponding height range, the first phosphor contained in the first wavelength conversion member 3 even if there is local uneven distribution of the second phosphor in the lateral direction. It is possible to properly evaluate the influence of the light from the outside extraction.

  Further, the reference area for determining the first area ratio and the second area ratio may be a partial area of the cross section of the second wavelength conversion member 4 instead of the entire area of the corresponding height range. At this time, the partial area to be referred to may be a rectangular area extending from the side of the light emitting element 1 to a length corresponding to the height of the light emitting element 1. That is, the first area ratio and the second area ratio are determined by the ratio of the area occupied by the cross section of the particles of the second phosphor in the rectangular region in the corresponding height range. When determining the first area ratio and the second area ratio, since the side surface of the light emitting element 1 is covered with the first wavelength conversion member 3, the remaining portion of the first wavelength conversion member 3 excluding the area occupied by the first wavelength conversion member 3 is excluded. The areas of the two-wavelength conversion member 4 will be compared.

For example, when the height of the light emitting element 1 is 200 μm, it is a region near the side of the light emitting element 1 of the second wavelength conversion member 4, and more preferably, a region in contact with the outer surface of the first wavelength conversion member 3. A rectangular region having a height of 100 μm and a width of 200 μm, which is a length in a direction perpendicular to the side surface of the light emitting element 1, is a region to be referred to in order to determine the first area ratio and the second area ratio. The region for determining the second area ratio is a region from the bottom surface of the recess 23a of the package 2 to a height of 100 μm, and the region for determining the first area ratio is 100 μm in height to the height of the upper surface of the light emitting element 1. It is a region up to a height of 200 μm.
By setting the reference region for determining the first area ratio and the second area ratio to be a region near the side of the light emitting element 1, the light from the first phosphor contained in the first wavelength conversion member 3 The impact on external extraction can be evaluated more appropriately.

  Further, the reference area for determining the first area ratio and the second area ratio is in the vicinity of the light emitting element 1 provided with the first wavelength conversion member 3, and has a predetermined area of any shape in the height range described above. It can also be an area. The shape of the region having the predetermined area can be, for example, a circle, a square, or another polygon. The size of the region having the predetermined area can be determined according to the particle size of the second phosphor. For example, when the shape of the area having the predetermined area is a square or a circle, the length of one side of the square or the diameter of the circle is 4 times or more the average particle diameter of the second phosphor or D50 which is the median particle diameter. It is preferable that Alternatively, the reference region may be a portion including 10 or more particles of the second phosphor.

The lower the first area ratio, the better the light emitted from the first phosphor can be extracted. Further, the smaller the first area ratio is, as compared with the second area ratio, the better the light emitted from the first phosphor can be extracted.
Specifically, the first area ratio is preferably 50% or less. In addition, the first area ratio is preferably half or less than the second area ratio. In particular, the first area ratio is more preferably 40% or less, further preferably 20% or less. Further, it is more preferable that the first area ratio is not more than two fifths of the second area ratio.

  The second wavelength conversion member 4 can be formed using a translucent resin material containing particles of the second phosphor. The resin material has good translucency to the wavelength of light emitted by the light emitting element 1, the first phosphor and the second phosphor, and has good weather resistance, light resistance and heat resistance as the sealing member. Materials are preferred. As such a material, the same material as that used for the resin portion 23 of the package 2 can be used. In addition, in the manufacturing process described later, it is preferable to use a thermosetting resin as the resin material in order to settle the particles of the second phosphor in a high concentration on the bottom surface 23b side of the recess 23a by allowing the particles to settle. Therefore, as the resin material, a silicone resin and a fluororesin which are excellent in heat resistance and light resistance are particularly preferable.

  As the first phosphor and the second phosphor that are wavelength conversion substances, those known in the art can be used. For example, among the phosphors shown below, the light emitting element 1, the first phosphor, and the It can be appropriately selected in consideration of the emission peak wavelength of each of the second phosphors and the emission color of the light emitting device 100.

For example, when the light emitting element 1 emits blue light, the first wavelength conversion member 3 contains a first phosphor that converts blue light into red light, and the second wavelength conversion member 4 emits blue light into green or green light. The light emitting device 100 that emits white light can be configured by including the second phosphor that converts yellow light.
Further, as the first phosphor and the second phosphor, two or more kinds of phosphor materials may be used for one or both of them.

Examples of the wavelength conversion substance include cerium-activated yttrium-aluminum-garnet (YAG)-based phosphors that emit green to yellow light, and cerium-activated lutetium-aluminum-garnet (LAG)-based fluorescence that emits green light. body, green to red in the activated with europium and / or chromium emitting nitrogen containing calcium aluminosilicate _{(CaO-Al 2 O 3 -SiO} 2) based phosphor, activated with europium emits blue to red silicate ( (Sr,Ba) ₂ SiO ₄ )-based phosphor, β-sialon phosphor whose composition for emitting green light is represented by (Si,Al) ₆ (O,N) ₈ :Eu, and composition is SrGa ₂ S ₄ :Eu A nitride-based fluorescent material such as a sulfide-based fluorescent material represented by the formula ( ₃ ), a CASN-based fluorescent material whose composition emitting red light is represented by CaAlSiN ₃ :Eu, or a SCASN-based fluorescent material represented by (Sr,Ca)AlSiN ₃ :Eu Body, a fluoride phosphor such as a KSF-based phosphor whose composition that emits red light is represented by (K ₂ SiF ₆ :Mn), a sulfide-based phosphor that emits red light, and a composition that emits red light (3. Examples thereof include a germanate-based (MGF-based) phosphor represented by 5MgO·0.5MgF ₂ ·GeO ₂ :Mn).
As the first phosphor and the second phosphor, those having an average particle diameter of about 1 μm to 40 μm are preferably used, and those having an average particle diameter of about 5 μm to 30 μm are more preferably used. By setting the average particle size of the first phosphor and the second phosphor in such a range, it is possible to arrange the phosphors at a high density while maintaining the brightness.

Moreover, it is preferable that the second phosphor satisfactorily reflects the light having the emission peak wavelength of the first phosphor. Here, the reflectance of the second phosphor at the emission peak wavelength of the first phosphor is preferably 60% or more, more preferably 70% or more, and further preferably 80% or more.
By using, as the second phosphor, a material that reflects the light emitted by the first phosphor well, the light emitted by the first phosphor can be efficiently extracted to the outside.
A detailed description of light extraction will be given later.

Here, such a combination of the first phosphor and the second phosphor will be described with reference to FIG. FIG. 3 is a graph showing an emission spectrum and a reflection spectrum of a phosphor example used in the light emitting device according to the embodiment.
In FIG. 3, the emission spectrum of the SCASN-based phosphor is shown by a solid line, the reflection spectrum is shown by a one-dot chain line, the emission spectrum of the LAG-based phosphor is shown by a broken line, and the reflection spectrum is shown by a two-dot chain line.

The SCASN-based phosphor emits red light whose emission peak wavelength is around 630 nm, and the LAG-based phosphor emits green light whose emission peak wavelength is around 540 nm.
The SCASN-based phosphor, which is a red phosphor, absorbs relatively large amounts of light emitted by the LAG-based phosphor in addition to blue light emitted by the light-emitting element 1 which is light having a wavelength shorter than the emission wavelength. Indicates. On the other hand, the LAG phosphor, which is a green phosphor, has a high reflectance in the entire wavelength range for the light emitted by the SCASN phosphor.
Therefore, the SCASN-based phosphor is used as the first phosphor, the LAG-based phosphor is used as the second phosphor, and the irradiation amount of the light from the second phosphor is reduced with respect to the first phosphor. By disposing the high-concentration region 4a of the first wavelength conversion member 3 and the second wavelength conversion member 4, the red light from the first phosphor and the green light from the second phosphor can be efficiently extracted to the outside. it can.
The details of light extraction from the light emitting device 100 will be described later.

Further, the second wavelength conversion member 4 may contain a light diffusing substance. As the light diffusing substance contained in the second wavelength conversion member 4, specifically, particles of a white pigment such as TiO ₂ or Al ₂ O ₃ can be used. Among them, TiO ₂ is preferable because it is relatively stable to moisture and has a high refractive index and has excellent thermal conductivity.

  Further, the average particle size of the particles of the light diffusing substance contained in the second wavelength conversion member 4 is preferably 0.001 μm or more and 10 μm or less, whereby high efficiency light scattering property can be obtained. In particular, the average particle size of the particles of the light diffusing substance in the second wavelength conversion member 4 is more preferably 0.001 μm to 0.05 μm. Thereby, a high light scattering effect, that is, a Rayleigh scattering effect is obtained, and the light extraction efficiency of the light emitting device 100 can be further increased. Further, since the light extraction efficiency is improved, the temperature increase due to the heat generation of the phosphor can be suppressed by reducing the usage amount of the phosphor, so that the deterioration of the phosphor is reduced and the reliability of the light emitting device 100 is improved. You can

The wire 5 electrically connects the external connection portion 13a of the n-side electrode 13 and the external connection portion 142a of the p-side electrode 14 of the light emitting element 1 to the lead electrodes 21 and 22 having the respective polarities. .. The wire 5 is also used to electrically connect one electrode of the protection element 6 and the lead electrode 21.
As the wire 5, Au, Cu, Al, Ag, or an alloy containing any of these metals as a main component can be preferably used.

The protective element 6 is preferably provided to protect the light emitting element 1 from electrostatic discharge. As the protection element 6, a Zener diode can be used in parallel with the light emitting element 1 and connected in reverse polarity. Further, as the protective element 6, a varistor, a resistor, a capacitor or the like can be used.
The protection element 6 is bonded to the lead electrode 22 by using a conductive bonding member 72, and is electrically connected to one electrode of the protection element 6. The other electrode of the protection element 6 is connected to the lead electrode 21 using the wire 5.

The bonding member 71 is a translucent adhesive material for bonding the light emitting element 1 to the lead electrode 21 provided on the bottom surface 23b of the recess 23a.
As the joining member 71, a resin material that is unlikely to be discolored or deteriorated by light or heat emitted from the light emitting element 1 is preferable, and further, a resin material that has good translucency and is used for the second wavelength conversion member 4 is refracted. It is preferably equal to or less than the rate. By setting the refractive index of the bonding member 71 to be equal to or less than the refractive index of the resin material used for the second wavelength conversion member 4, the light incident on the bonding member 71 is separated between the bonding member 71 and the second wavelength conversion member 4. It can be efficiently taken out without being totally reflected at the interface. As such a resin material, a silicone-based die bond resin having a siloxane skeleton is preferable. Examples of silicone-based die bond resins include silicone resins, silicone hybrid resins, and silicone-modified resins.

  The joining member 72 is an electrically conductive adhesive material such as solder for joining the protective element 6 to the lead electrode 22 and electrically connecting one electrode of the protective element 6 and the lead electrode 22.

(Modification)
In this embodiment, the resin package is used as the base on which the light emitting element 1 is mounted, but a ceramic package may be used.
Further, although the package 2 having the recess 23a is used as the base, a flat plate base having no recess 23a may be used.

[Operation of light emitting device]
Next, the operation of the light emitting device 100 will be described with reference to FIGS. 1A to 1C, 4A and 4B.
FIG. 4A is a diagram illustrating light extraction in the light emitting device according to the embodiment. FIG. 4B is a diagram illustrating light extraction in the light emitting device according to the embodiment, and is an enlarged view of a region IVB in FIG. 4A.
For convenience of description, the light emitting element 1 emits blue light, and the first wavelength conversion member 3 contains particles of a first phosphor that absorbs blue light and emits red light as a wavelength conversion material, and has a second wavelength. It is assumed that the conversion member 4 contains particles of a second phosphor that absorbs blue light and emits green light as a wavelength conversion substance. Further, the light reflection film 16 has a reflection characteristic of reflecting blue light emitted by the light emitting element 1 and transmitting red light emitted by the first phosphor contained in the first wavelength conversion member 3.

When the light emitting device 100 is connected to the external power source through the lead electrodes 21 and 22, current is supplied to the light emitting element 1 through the wire 5, and the light emitting element 1 emits blue light. Of the blue light emitted from the light emitting element 1, the light ray L1 propagating upward is green light due to the second phosphor in the high concentration region 4a of the second wavelength conversion member 4 arranged on the upper surface of the light emitting element 1. Is converted into a light beam L2 and is extracted as a light beam L2 from the upper surface of the light emitting device 100.
In the light emitting device 100 of the present embodiment, the high concentration region 4a containing the second phosphor at a high concentration has the first wavelength conversion member 3 containing the first phosphor on the upper surface side which is the light extraction surface of the light emitting device 100. Is not provided. Therefore, the second phosphor can efficiently convert the blue light emitted from the upper surface of the light emitting element 1 into the green light and take it out to the outside.

The blue light ray L3 propagating laterally in the light emitting element 1 is converted into red light by the first phosphor contained in the first wavelength conversion member 3 arranged on the side surface of the light emitting element 1. ..
A part of the red light propagates upward in a region where the concentration of the second phosphor contained in the second wavelength conversion member 4 is low, like the light ray L4, and is extracted to the outside.
In the light emitting device 100 of the present embodiment, since the region in which the concentration of the second phosphor is low is provided in a part of the outer surface of the first wavelength conversion member 3, the red light converted by the first phosphor is emitted. , Can be taken out efficiently.

Further, the light ray L5 propagating downward as another part of the red light is reflected by the second phosphor contained in the high concentration region 4a of the bottom surface 23b of the recess 23a. The light ray L6 that is the reflected light propagates upward in the second wavelength conversion member 4 and is extracted to the outside.
In the light emitting device 100 of the present embodiment, by using a material having a high reflectance for the red light emitted by the first phosphor as the second phosphor, the high concentration region 4a arranged on the bottom surface 23b of the recess 23a is changed to the first phosphor. 1 Functions as a reflection layer for the light emitted by the phosphor. Therefore, the red light emitted by the first phosphor can be efficiently extracted to the outside.

  Further, in the blue light emitted from the light emitting element 1, the light ray L11 propagating downward is reflected by the light reflection film 16 provided on the lower surface of the light emitting element 1 and propagates upward as indicated by a light ray L12.

  In the blue light emitted from the light emitting element 1, the light ray L13 propagating in the lateral direction is converted into red light by the first phosphor contained in the first wavelength conversion member 3. Of the red light, the light ray L14 propagating toward the low-concentration region of the second wavelength conversion member 4 in which the concentration of the second phosphor is low propagates in the second wavelength conversion member 4 as indicated by a light ray L15. Then, it is taken out.

  In the red light, the light ray L16 propagating toward the high-concentration region 4a of the second wavelength conversion member 4 is indicated by light rays L17, L18, and L19 by the particles of the second phosphor contained in the high-concentration region 4a. As described above, the particles are propagated while being scattered by the particles of the second phosphor, and further propagated through the low concentration region of the second phosphor, which is the upper layer portion of the second wavelength conversion member 4, and taken out to the outside. Here, by using a material having a high reflectance for red light as the second phosphor, it is possible to scatter the red light, propagate the light while suppressing the reduction of the light amount of the red light, and take it out to the outside.

  Of the red light, the light ray L20 that is incident on the light emitting element 1 and propagates downward is transmitted through the light reflection film 16 and is incident on the translucent bonding member 71. The light ray L21 propagating downward in the joining member 71 is reflected by the upper surface of the lead electrode 21 provided on the bottom surface 23b of the recess 23a, and propagates upward as indicated by a light ray L22. The light ray L22 is transmitted through the light reflection film 16, propagates upward in the light emitting element 1 as shown by a light ray L23, and is extracted to the outside from the upper surface side of the light emitting element 1.

Further, a part of the red light incident on the joining member 71 propagates in the joining member 71 in the lateral direction as indicated by a light ray L24, and the second wavelength conversion member provided on the bottom surface 23b of the recess 23a. 4 enters the high-concentration region 4a and propagates while being scattered by the particles of the second phosphor as shown by the light rays L25, L26, L27, and L2, and the second layer that is the upper layer portion of the second wavelength conversion member 4. It propagates through the low concentration region of the phosphor and is taken out to the outside.
In this way, by increasing the number of paths through which the red light is extracted to the outside through the joining member 71, the amount of red light in the output light of the light emitting device 100 can be increased. As a result, the color rendering of the light emitting device 100, particularly for the red color chart, can be improved.

Note that part of the blue light incident on the high-concentration region 4a of the first wavelength conversion member 3 provided on the side surface of the light emitting element 1 and the second wavelength conversion member 4 provided on the upper surface of the light emitting element 1 is wavelength converted. Instead, the light passes through the high-concentration regions 4a of the first wavelength conversion member 3 and the second wavelength conversion member 4.
Part of the blue light transmitted through the high-concentration regions 4a of the first wavelength conversion member 3 and the second wavelength conversion member 4 is extracted from the light emitting device 100 to the outside as blue light. The other part of the blue light is reflected by the interface of each member arranged in the recess 23a, and is the second phosphor contained in the high-concentration region 4a provided on the bottom surface 23b of the recess 23a. The wavelength is converted into green light and the light is extracted to the outside.

  Further, a part of the green light emitted from the high-concentration region 4a of the second wavelength conversion member 4 is incident on the first wavelength conversion member 3 and converted into red light. In the light emitting device 100 of the present embodiment, The one-wavelength conversion member 3 and the high-concentration region 4a of the second wavelength conversion member 4 are arranged so that the regions in contact with each other are reduced. Therefore, it is possible to prevent the green light from being converted into the red light and reducing the component of the green light.

As described above, a part of the blue light emitted from the light emitting element 1 is extracted to the outside as it is, and a part of the blue light is converted to red light by the first phosphor in the first wavelength conversion member 3 and extracted to the outside. Part of the light is converted into green light by the second phosphor mainly in the high-concentration region 4a of the second wavelength conversion member 4 and is extracted to the outside. Then, white light obtained by mixing these lights is output from the light emitting device 100.
At this time, the red light, which is the light emitted by the first phosphor, can be efficiently extracted to the outside, so that the color rendering of the light emitting device 100 can be improved. In addition, since the green light emitted from the second phosphor can be efficiently extracted to the outside, the output of the light emitting device 100 can be increased.

[Method of manufacturing light emitting device]
Next, a method for manufacturing the light emitting device 100 will be described with reference to FIGS. 5 to 8B.
FIG. 5 is a flowchart showing the procedure of the method for manufacturing the light emitting device according to the embodiment. FIG. 6A is a cross-sectional view showing a first light emitting element placement step in the first wavelength conversion member placement step in the method for manufacturing a light emitting device according to the embodiment. FIG. 6B is a cross-sectional view showing the first resin disposing step in the first wavelength converting member disposing step in the method for manufacturing the light emitting device according to the embodiment. FIG. 6C is a cross-sectional view showing a first resin cutting step in the first wavelength conversion member arranging step in the method for manufacturing the light emitting device according to the embodiment. FIG. 7 is a cross-sectional view showing a second light emitting element disposing step in the method for manufacturing the light emitting device according to the embodiment. FIG. 8A is a cross-sectional view showing a second resin arranging step in the second wavelength conversion member arranging step in the method for manufacturing the light emitting device according to the embodiment. FIG. 8B is a cross-sectional view showing a second phosphor sedimentation step in the second wavelength conversion member arranging step in the method for manufacturing the light emitting device according to the embodiment.
Note that FIGS. 7 to 8B show cross sections at positions corresponding to the IC-IC line in FIG. 1B.

  The manufacturing method of the light emitting device 100 according to the embodiment includes a package preparing step S11, a light emitting element preparing step S12, a first wavelength conversion member arranging step S13, a second light emitting element arranging step S14, and a second wavelength converting member arrangement. Step S15 and are included. The first wavelength conversion member arranging step S13 includes a first light emitting element arranging step S131, a first resin arranging step S132, a first resin curing step S133, and a first resin cutting step S134. The second wavelength conversion member arranging step S15 includes a second resin arranging step S151, a second phosphor settling step S152, and a second resin curing step S153.

The package preparation step (step of preparing the base) S11 is a step of preparing the package 2 which is the base of the light emitting device 100. The package 2 prepared in this step is in a state in which the light emitting element 1, the first wavelength conversion member 3 and the second wavelength conversion member 4 are not arranged.
In the package preparation step S11, in order to prepare the package 2, for example, it may be manufactured by a molding method using a mold such as a transfer molding method, an injection molding method, a compression molding method, an extrusion molding method, You may make it obtain a commercial package.

An example of a method of manufacturing the package 2 will be described.
First, a sheet metal is punched to form a lead frame having the outer shapes of the lead electrodes 21 and 22. Next, the lead frame is sandwiched by upper and lower molds having a cavity in the shape of the resin portion 23, and a resin material is injected from a gate hole provided in a part of the mold. Next, after the injected resin material is cured or solidified, it is taken out from the mold. The package 2 can be manufactured by performing the above steps. In addition, when a plurality of packages 2 are manufactured in a state where they are connected by a lead frame, the lead frame is cut to separate the packages 2 into individual pieces.
The individual pieces of the package 2 may be performed after the second wavelength conversion member arranging step S15.

  The light-emitting element preparation step S12 is a step of preparing the light-emitting element 1 that has been separated into individual pieces.

  The first wavelength conversion member placement step S13 is a step of placing the first wavelength conversion member 3 so as to cover the side surface of the light emitting element 1 prepared in the light emitting element preparation step S12. As described above, the first wavelength conversion member disposing step S13 includes the first light emitting element disposing step S131, the first resin disposing step S132, the first resin curing step S133, and the first resin cutting step S134. Has been.

The first light emitting element placement step S131 is a step of placing the light emitting element 1 on the support member 81. The support member 81 is a flat plate-shaped pedestal, and is configured to be able to hold the light emitting element 1 so that the light emitting element 1 does not fall off from the support member 81 during the first resin placement step S132 to the first resin cutting step S134. There is.
Therefore, an adhesive layer may be provided on the upper surface of the support member 81, and the light emitting element 1 may be held on the upper surface side by an adhesive force. Further, by using a thermosetting resin or an ultraviolet curable resin as the adhesive layer, after the first wavelength conversion member 3 is formed, the adhesive layer is heated or irradiated with ultraviolet rays to be cured to lose the adhesive strength. Then, the light emitting element 1 with the first wavelength conversion member 3 can be easily peeled from the support member 81.

In the present embodiment, the plurality of light emitting elements 1 are arranged on the support member 81 with a predetermined space. Here, the predetermined interval is the width of the first wavelength conversion member 3 to be arranged, that is, the thickness in the direction perpendicular to the side surface of the light emitting element 1 and the width serving as a cutting margin in the first resin cutting step S134. It is an interval considered.
In the present embodiment, the plurality of light emitting elements 1 are arranged on the support member 81, but one light emitting element 1 may be arranged.

The first resin arranging step S132 is a step of arranging the first resin 31, which is a resin material containing particles of the first phosphor, so as to cover the side surface of the light emitting element 1 arranged on the supporting member 81. ..
For the first resin 31, it is preferable to use a thermosetting resin as a resin material that is a base material. The first resin 31 can be arranged by applying a slurry containing an uncured thermosetting resin and particles of the first phosphor on the upper surface side of the support member 81 by various application methods. .. Here, the applied slurry can be adjusted to have a viscosity suitable for the application method by adjusting the addition amount of the solvent and the addition amount of the filler such as silica.
Examples of the method for applying the slurry include a spray method, a silk screen printing method, an inkjet method, a potting method, a spin coating method and the like. Among these, the spin coating method is simple in order to fill the slurry between a plurality of light emitting elements 1 without applying the slurry to the upper surface side of the light emitting element 1.

The first resin curing step S133 is a step of curing the first resin 31.
When a thermosetting resin is used as the first resin 31, the first resin 31 is heated by heat treatment.
Can be cured.
A thermoplastic resin can also be used as the first resin 31. In this case, in the first resin placement step S132, the first resin 31 containing the particles of the first phosphor is melted and placed on the side surface of the light emitting element 1. Then, in 1st resin hardening process S133, the 1st resin 31 is solidified by cooling or cooling.

The first resin cutting step S134 is a step of cutting the first resin 31 along the boundary line BD set between the light emitting elements 1. Specifically, the first resin 31 is cut by forming a groove penetrating in the thickness direction in the first resin 31 along the boundary line BD using the dicer 82 or the like. At this time, the first resin 31 is cut so that a predetermined width remains from the side surface of the light emitting element 1. The first resin 31 left on the side surface of the light emitting element 1 becomes the first wavelength conversion member 3.
The light emitting device 1 with the first wavelength conversion member 3 formed through the above steps is used by peeling it from the support member 81.

  Any of the step of forming the light emitting element 1 with the first wavelength conversion member 3 including the light emitting element preparation step S12 and the first wavelength conversion member placement step S13 and the package preparation step S11 may be performed first, You may make it perform in parallel.

The second light emitting element arranging step S14 is a step of mounting the light emitting element 1 with the first wavelength conversion member 3 in the recess 23a of the package 2 which is the base. First, the light-emitting element 1 with the first wavelength conversion member 3 is bonded onto the lead electrode 21 which is the bottom surface 23b of the recess 23a of the package 2 using the translucent bonding member 71. At this time, the light emitting element 1 with the first wavelength conversion member 3 is bonded to the bottom surface 23b of the recess 23a with the surface on which the light reflection film 16 is provided facing downward.
Next, the conductive wire 5 is used to electrically connect the n-side electrode 13 and the p-side electrode 14 of the light emitting element 1 to the lead electrodes 21 and 22 having the respective polarities. Further, in this step, the protective element 6 is also mounted in the recess 23 a of the package 2 by using the joining member 72 and the wire 5.

  The second wavelength conversion member arranging step S15 is a step of arranging the second wavelength conversion member 4 so as to cover the upper surface and the side surface of the light emitting element 1 with the first wavelength conversion member 3. As described above, the second wavelength conversion member arranging step S15 includes the second resin arranging step S151, the second phosphor settling step S152, and the second resin curing step S153.

The second resin arranging step S151 is a step of arranging the second resin 41 containing the particles of the second phosphor so as to cover the upper surface and the side surface of the light emitting element 1 with the first wavelength conversion member 3.
For the second resin 41, a thermosetting resin is used as a resin material that is a base material. A slurry containing particles of the second phosphor and a resin material, the viscosity of which is adjusted with a solvent and, if necessary, a filler is prepared, and is supplied so as to fill the inside of the recess 23a using a dispenser 83, for example. ..
The second phosphor has a larger specific gravity than the uncured resin material.

The second phosphor settling step S152 is a step of holding the second resin 41 supplied to the recess 23a of the package 2 in an uncured state and allowing the particles of the second phosphor to settle on the bottom surface 23b side of the recess 23a. .. Letting the particles of the second phosphor settle on the bottom surface 23b side of the recess 23a means that the particles are settled on the bottom surface 23b, and in the region where the light emitting element 1 with the first wavelength conversion member 3 is arranged, the first wavelength conversion member. It means to settle on the upper surface of the light emitting device 1 with the number 3. The particles of the second phosphor are settled, and a high-concentration region 4a containing the particles of the second phosphor in a relatively high concentration is formed in the second wavelength conversion member 4.
As described above, since the second phosphor has a larger specific gravity than the uncured resin material, it sediments downward in the direction of gravity. Therefore, by leaving the second resin 41 in an uncured state, the second phosphor can be naturally settled.

Alternatively, the particles of the second phosphor may be forcibly settled toward the bottom surface 23b of the recess 23a using a centrifuge. At this time, the package 2 in which the uncured second resin 41 is arranged is installed in the centrifuge so that the centrifugal force acts vertically downward on the bottom surface 23b.
By forcibly sedimenting the particles of the second phosphor by using a centrifuge, the time required for this step can be shorter than that for spontaneous sedimentation.
Further, the forced sedimentation allows the particles of the second phosphor to be arranged in a higher concentration in a narrower area on the bottom face 23b side than in the case of spontaneous sedimentation. In other words, on the upper side surface of the first wavelength conversion member 3, it is possible to increase the region where the particles of the second phosphor are not arranged or are arranged at a low concentration. As a result, it is possible to further increase the efficiency with which the light whose wavelength is converted by the first wavelength conversion member 3 is extracted to the outside.

The second resin curing step S153 is a step of curing the second resin 41 by performing heat treatment after the particles of the second phosphor are settled. As a result, the second wavelength conversion member 4 is formed.
The light emitting device 100 can be manufactured by the procedure described above.

(Modification)
Note that, as described above, the light emitting device may be configured using a base that does not have the recess 23a. In this case, in the second wavelength conversion member arranging step S15, the frame body is arranged so as to surround the light emitting element 1 with the first wavelength conversion member 3 in a plan view, and the uncured second resin 41 is arranged in the frame body. Then, the particles of the second phosphor are allowed to settle, and the second resin 41 is cured to form the second wavelength conversion member 4, and then the frame can be removed to form the second wavelength conversion member 4.
In addition, without using the frame body, the second resin 41 adjusted to have an appropriate viscosity is dropped by the potting method, and the second resin 41 is arranged so as to cover the light emitting element 1 with the first wavelength conversion member 3, and the second phosphor The particles may be allowed to spontaneously set and then hardened.

<Example 1>
As examples and comparative examples, light emitting devices having the shapes shown in FIGS. 1A to 1C were manufactured under the following conditions. Further, with respect to each of the manufactured light emitting devices, the luminous flux, the average color rendering index Ra defined by Japanese Industrial Standard JIS Z8726:1990, and the special color rendering index R9 for the red color chart were measured.

[Production conditions]
(Light emitting element)
・Plan view shape: Square with a side of 650 μm ・Thickness: 200 μm
・Semiconductor material: gallium nitride based semiconductor ・Substrate: sapphire ・Emission peak wavelength: 448 nm
- light-reflecting layer: DBR layer (the layer in contact with the sapphire substrate as SiO _2, 21-layer laminate of SiO ₂ and Nb2O5 alternately)
The DBR film has a reflectance of 98% at the incident angle of 0° with respect to the emission peak wavelength of the light emitting element, and has a design with respect to the emission peak wavelength of the first phosphor. The reflectance is 81% when the angle is 0°.

(package)
A package of model number NFxW757G manufactured by Nichia Corporation was used. The main specifications are shown below.
-Plane shape: The outer shape is a square with one side of 3.0 mm
The opening of the recess is a square with a side of 2.6 mm.-Resin part: White resin-Lead electrode: There is a reflective film by Ag plating on the top surface-Light emitting element bonding member (die bond resin): Dimethyl silicone resin

(First wavelength conversion member)
Base material: silicone resin (product name SCR-1011 manufactured by Shin-Etsu Chemical Co., Ltd.), refractive index 1.53
First phosphor: SCASN-based phosphor (emission peak wavelength: 620 nm), average particle size 10 μm
Content of first phosphor: 100 parts by mass relative to 100 parts by mass of base material

(Second wavelength conversion member)
Base material: phenyl silicone resin (product name OE-6630 manufactured by Toray Dow Corning Co., Ltd.), refractive index 1.53
Second phosphor: LAG phosphor (emission peak wavelength: 517 nm), average particle size 22 μm
-Content of the second phosphor: 60 parts by mass with respect to 100 parts by mass of the base material-Light diffusing agent: 18.2 parts by mass with respect to 100 parts by mass of the base material-When forming the second wavelength conversion member, The 2 phosphors were allowed to settle spontaneously.

(Comparative Example 1: Conditions different from Example 1)
-Phosphor corresponding to the first phosphor: SCASN-based phosphor (emission peak wavelength: 625 nm)
However, in order to match the chromaticity and the average color rendering index Ra with those of Example 1, a SCASN-based phosphor whose emission peak wavelength was slightly different from that of Example 1 was used.
Content of phosphor corresponding to the first phosphor: 3 parts by mass with respect to 100 parts by mass of the base material of the sealing member filling the recess of the package Phosphor corresponding to the second phosphor: LAG phosphor (Emission peak wavelength: 517 nm)
Content of phosphor corresponding to the second phosphor: 72 parts by mass with respect to 100 parts by mass of the base material of the sealing member filling the recess of the package. First phosphor and second phosphor in Comparative Example 1. Was dispersed in the sealing member corresponding to the first wavelength conversion member and the second wavelength conversion member of Example 1 without dividing the arrangement region.

[Evaluation results]
Tables 1 to 3 show the measurement results of the items described above for Example 1 and Comparative Example 1. Table 1 shows samples of Example 1 and Comparative Example 1 in the case where the DBR film is not provided as the light reflection film on the lower surface of the light emitting device. Table 2 shows samples of Example 1 and Comparative Example 1 in the case where a DBR film was provided as a light reflecting film on the lower surface of the light emitting device. Table 3 shows samples of Example 1 in the case where the DBR film is provided as the light reflecting film on the lower surface of the light emitting element and the case where the DBR film is not provided.
In Tables 1 to 3, x and y values are chromaticity values calculated based on the XYZ color system defined by CIE (International Commission on Illumination). The same applies to Tables 4 and 5 described later.
Further, in each table, the samples shown in the same table were produced under the same conditions except for the explicitly shown differences, but the samples shown in different tables had slightly different production conditions. There is a case.

As shown in Table 1, it can be confirmed that in the case where the DBR film is not provided, the luminous flux and the average color rendering index Ra of Example 1 are higher than those of Comparative Example 1. Further, it can be confirmed that the special color rendering index R9 for the red color chart is higher in Comparative Example 1.
In Comparative Example 1, since the first phosphor and the second phosphor are arranged in a mixed state, a large amount of green light emitted by the second phosphor is converted into red light by the second phosphor. it is conceivable that. On the other hand, in Example 1, the first phosphor and the second phosphor are arranged separately from each other, and the green light emitted by the second phosphor is arranged so as not to be easily absorbed by the first phosphor. Has been done. As a result, in Example 1, the decrease in the light amount of green light having high visibility is suppressed, so that the luminous flux becomes relatively high and the average color rendering evaluation, which is the evaluation value of the color rendering properties with respect to the color charts of various hues. It is considered that the number Ra also increases.
Further, as shown in Table 2, it can be confirmed that the light flux, the average color rendering index Ra, and the special color rendering index R9 have the same tendency as in the case without the DBR film even when the DBR film is provided.

In Comparative Example 1, the light amount of red light increases, so the special color rendering index R9 becomes higher than that in Example 1. On the other hand, in Example 1, although the special color rendering index R9 is lowered, the average color rendering index Ra is further improved, and as a whole, the color rendering property of Example 1 is higher. Can be said to have been.
Therefore, by disposing the first phosphor and the second phosphor separately from each other as in Example 1, by disposing the light emitted from the second phosphor so that it is difficult for the first phosphor to absorb the light. It can be seen that the luminous flux and the color rendering properties are improved.

Further, as shown in Table 3, it can be confirmed that the luminous flux is improved in Example 1. In addition, it can be confirmed that in Example 1, the special color rendering index R9 is improved.
Therefore, it can be seen that by providing the DBR film, the efficiency of extracting the blue light emitted from the light emitting element from the upper surface side is improved, so that the output of the light emitting device can be improved.
In addition, the amount of red light is increased by providing the DBR film with a property of transmitting red light and by bonding the light emitting element with a translucent bonding member to increase the extraction path of the red light to the outside. It can be seen that the color rendering property for the red color chart can be improved.

<Example 2>
(Production conditions)
The second embodiment is the same as the first embodiment except that the contents and particle sizes of the first phosphor and the second phosphor are slightly different from those of the first embodiment.
-Comparative example 2 differs from example 2 in that the second phosphor was dispersed in the base material of the second wavelength conversion member without settling. The other conditions are the same as those in the second embodiment.

[Evaluation results]
Tables 4 and 5 show the measurement results of the items described above for Example 2 and Comparative Example 2. Table 4 shows samples of Example 2 and Comparative Example 2 when the DBR film was not provided as the light reflecting film on the lower surface of the light emitting device. Table 5 shows samples of Example 2 and Comparative Example 2 in the case where the DBR film was provided as the light reflecting film on the lower surface of the light emitting device.

As shown in Table 4, in the case where the DBR film was not provided, the luminous flux and the average color rendering index Ra of Example 2 were substantially the same as those of Comparative Example 2, but the special color rendering index R9 for the red color chart was used. However, it can be confirmed that it is improved by about 1%.
Further, as shown in Table 5, it can be confirmed that, even in the case where the DBR film is provided, Example 2 has the same tendency as that of the sample without the DBR film in comparison with Comparative Example 2.
Therefore, as in the light emitting device of Example 2, it is understood that the color rendering property for the red color chart is improved by allowing the second phosphor to settle on the bottom surface side.

  The light emitting device according to the present embodiment has been described above more specifically with respect to the mode for carrying out the invention, but the gist of the present invention is not limited to these descriptions, and the scope of the claims is not limited thereto. Must be broadly interpreted on the basis of. Needless to say, various changes and modifications based on these descriptions are also included in the spirit of the present invention.

  A light emitting device according to an embodiment of the present disclosure is used in a backlight light source of a liquid crystal display, various lighting devices, a large display, various display devices such as advertisements and destination guides, and further in digital video cameras, facsimiles, copiers, scanners, and the like. It can be used for various light sources such as an image reading device and a projector device.

DESCRIPTION OF SYMBOLS 1 Light emitting element 11 Substrate 12 Semiconductor laminated body 12n n-type semiconductor layer 12a Active layer 12p p-type semiconductor layer 12b Step part 13 n-side electrode 13a External connection part 13b Extension part 14 p-side electrode 141 Transparent electrode 142 Pad electrode 142a External Connection part 142b Stretched part 15 Protective film 15n, 15p Opening part 16 Light reflection film 2 Package (base)
21, 22 Lead electrode 23 Resin portion 23a Recessed portion 23b Bottom surface 23c Cathode mark 3 First wavelength conversion member 31 First resin 4 Second wavelength conversion member 41 Second resin 4a High concentration region 5 Wire 6 Protective element 71 Joining member 72 Joining member 81 Supporting Member 82 Dicer 83 Dispenser 100 Light Emitting Device BD Boundary Line

Claims (23)

Base
A light emitting element arranged on the base,
A first wavelength conversion member that covers a side surface of the light emitting element and that includes a first phosphor that converts light emitted by the light emitting element into light having an emission peak wavelength longer than an emission peak wavelength of the light emitting element;
The light emitted from the light emitting element is converted into light having an emission peak wavelength longer than the emission peak wavelength of the light emitting element and shorter than the emission peak wavelength of the first phosphor, covering the upper surface of the light emitting element and the base. A second wavelength conversion member containing a second phosphor to
In the portion of the second wavelength conversion member that covers the base, the first concentration, which is the concentration of the second phosphor at the height of the upper surface of the light emitting element, has the first concentration at the height of the lower surface of the light emitting element. A light emitting device in which the second phosphor reflects light having an emission peak wavelength of the first phosphor, which is lower than a second concentration which is the concentration of the two phosphors.   The light emitting device according to claim 1, wherein the first concentration is equal to or less than half of the second concentration. Base
A light emitting element arranged on the base,
A first wavelength conversion member that covers a side surface of the light emitting element and that includes a first phosphor that converts light emitted by the light emitting element into light having an emission peak wavelength longer than an emission peak wavelength of the light emitting element;
The light emitted from the light emitting element is converted into light having an emission peak wavelength longer than the emission peak wavelength of the light emitting element and shorter than the emission peak wavelength of the first phosphor, covering the upper surface of the light emitting element and the base. A second wavelength conversion member containing a second phosphor to
In a cross section of the second wavelength conversion member cut from the upper surface to the lower surface, a cross section of the second phosphor at a height from half the height of the light emitting element to the upper surface of the light emitting element. The first area ratio, which is the proportion of the area occupied by the second phosphor, is the proportion of the area occupied by the cross section of the second phosphor at a height that is half the height of the light emitting element from the upper surface of the base. A light-emitting device that has a smaller area ratio.   The first area ratio and the second area ratio are determined by the ratio of the area occupied by the cross section of the second phosphor in the entire area of the corresponding height range in the cross section of the second wavelength conversion member. The light emitting device according to claim 3.   The first area ratio and the second area ratio are the second area in the rectangular region extending from the side of the light emitting device to the length of the height of the light emitting device in the cross section of the second wavelength conversion member. The light emitting device according to claim 3, wherein the light emitting device is defined by the ratio of the area occupied by the cross section of the phosphor.   The light emitting device according to claim 3, wherein the first area ratio is 50% or less.   The light emitting device according to claim 3, wherein the first area ratio is equal to or less than half of the second area ratio. The base has a recess opening on the upper surface side,
The light emitting device according to claim 1, wherein the light emitting element is disposed on a bottom surface of the recess. Base
A light emitting element arranged on the base,
A first wavelength conversion member that covers a side surface of the light emitting element and that includes a first phosphor that converts light emitted by the light emitting element into light having an emission peak wavelength longer than an emission peak wavelength of the light emitting element;
The light emitted from the light emitting element is converted into light having an emission peak wavelength longer than the emission peak wavelength of the light emitting element and shorter than the emission peak wavelength of the first phosphor, covering the upper surface of the light emitting element and the base. A second wavelength conversion member containing a second phosphor to
In the second wavelength conversion member, the second phosphor is arranged in layers in at least the portion arranged on the base, and the thickness of the layer is three quarters of the height of the light emitting element. The following is a light-emitting device.   The said 2nd wavelength conversion member WHEREIN: At least the part arrange|positioned at the said base WHEREIN: The said 2nd fluorescent substance is not substantially arrange|positioned above 3/4 of the height of the said light emitting element. 9. The light emitting device according to item 9. The light emitting element emits blue light,
The first phosphor emits red light,
The light emitting device according to claim 1, wherein the second phosphor emits green to yellow light.   The light emitting device according to any one of claims 1 to 11, wherein the light emitting element is joined to the base via a joining member having a lower surface having a light transmitting property. The light emitting element has a light reflecting film on the lower surface,
The light emitting device according to claim 12, wherein the light reflection film reflects light having an emission peak wavelength of the light emitting element and transmits light having an emission peak wavelength of the first phosphor.   14. The light reflection film is a distributed Bragg reflector (DBR) film made of a dielectric multilayer film, reflects the light emitted by the light emitting element, and transmits the light emitted by the first wavelength conversion member. The light emitting device described.   In the second wavelength conversion member, the second phosphor is arranged in layers at least in the portion arranged on the base, and the thickness of the layer is 4 times the height of the first wavelength conversion member. 15. The light emitting device according to claim 1, wherein the light emitting device has a ratio of 3/3 or less. The first wavelength conversion member does not cover the upper surface of the light emitting element,
The light emitting device according to claim 1, wherein the second wavelength conversion member is in contact with an upper surface of the light emitting element. Disposing at least one light emitting element on the support member,
Disposing a first wavelength conversion member containing a first phosphor on a side surface of the light emitting element;
Arranging the light emitting element provided with the first wavelength conversion member on a base,
A method of manufacturing a light-emitting device, comprising the steps of covering the upper surface and the side surface of the light emitting element provided with the first wavelength conversion member and disposing a second wavelength conversion member containing a second phosphor in this order. .. The base has a recess opening on the upper surface side,
18. The light emission according to claim 17, wherein in the step of disposing the light emitting element provided with the first wavelength conversion member, the light emitting element provided with the first wavelength conversion member is disposed on the bottom surface of the recess. Device manufacturing method. The step of disposing the first wavelength conversion member includes
Disposing an uncured first resin containing the first phosphor between the plurality of light emitting elements on the support member,
Curing the first resin,
19. The method of manufacturing a light emitting device according to claim 17, further comprising: a step of cutting the first resin by forming a groove penetrating in a thickness direction between the light emitting elements in this order. .. The step of forming the second wavelength conversion member includes
Disposing an uncured second resin containing the particles of the second phosphor in the recess;
Forcibly settling the particles of the second phosphor on the bottom surface side of the recess,
The method for manufacturing a light emitting device according to claim 17, further comprising: a step of curing the second resin in this order.   21. The method for manufacturing a light emitting device according to claim 17, wherein a light reflecting film is provided on a surface of the light emitting element disposed on the support member, the surface facing the support member.   22. The method for manufacturing a light emitting device according to claim 17, wherein in the step of disposing the first wavelength conversion member, the first wavelength conversion member is not disposed on the upper surface of the light emitting element.   23. The manufacturing of the light emitting device according to claim 17, wherein, in the step of disposing the second wavelength conversion member, the second wavelength conversion member is disposed so as to be in contact with the upper surface of the light emitting element. Method.

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