JP2020170862A - Light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device capable of suppressing unevenness in light distribution chromaticity. SOLUTION: A light emitting element having a first surface and a second surface located on the opposite side of the first surface, a light guide member covering the side surface of the light emitting element, and the first surface are covered. , The first wavelength conversion member having the first base material and the first wavelength conversion particle, the side surface of the light emitting element, the side surface of the light guide member, and the side surface of the first wavelength conversion member, and the reflection in contact with the light emitting element. The first wavelength conversion member has a thickness of 60 μm or more and 120 μm or less, and the average particle size of the first wavelength conversion particle is 4 μm or more and 12 μm or less, and is the center of the first wavelength conversion particle. A light emitting device having a particle size of 4 μm or more and 12 μm or less, and 60% by weight or more and 75% by weight or less of the first wavelength conversion particles with respect to the total weight of the first wavelength conversion member. [Selection diagram] FIG. 2A

Description

The present invention relates to a light emitting device.

A light emitting element, an optical layer arranged on the light emitting element that transmits at least a part of the light emitted by the light emitting element, and a plate shape mounted on the optical layer and transmitting at least a part of the light emitted by the light emitting element. A light emitting device having an optical member is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-134355

When used as a backlight or lighting, there is a demand for a light emitting device capable of obtaining light having a uniform chromaticity regardless of the location. Therefore, an object of the embodiment of the present invention is to provide a light emitting device capable of suppressing unevenness in light distribution chromaticity.

The light emitting device according to one aspect of the present invention includes a light emitting element having a first surface and a second surface located on the opposite side of the first surface, and a light guide member covering the side surface of the light emitting element. The first surface is covered, and the first wavelength conversion member having the first base material and the first wavelength conversion particles, the side surface of the light emitting element, the side surface of the light guide member, and the side surface of the first wavelength conversion member are covered. The first wavelength conversion member has a thickness of 60 μm or more and 120 μm or less, and the average particle size of the first wavelength conversion particles is 4 μm or more and 12 μm or less, wherein the first wavelength conversion member is provided with a reflection member in contact with the light emitting element. The central particle size of the first wavelength conversion particles is 4 μm or more and 12 μm or less, and the first wavelength conversion particles are 60% by weight or more and 75% by weight or less with respect to the total weight of the first wavelength conversion member.

According to the light emitting device of the embodiment according to the present invention, it is possible to provide a light emitting device capable of suppressing unevenness in light distribution chromaticity.

FIG. 1A is a schematic perspective view of the light emitting device according to the first embodiment. FIG. 1B is a schematic perspective view of the light emitting device according to the first embodiment. FIG. 1C is a schematic front view of the light emitting device according to the first embodiment. FIG. 2A is a schematic cross-sectional view taken along the line 2A-2A of FIG. 1C. FIG. 2B is a schematic cross-sectional view taken along the line 2B-2B of FIG. 1C. FIG. 2C is a schematic cross-sectional view of a modified example of the light emitting device according to the first embodiment. FIG. 2D is a schematic cross-sectional view of a modified example of the light emitting device according to the first embodiment. FIG. 3A is a schematic rear view of the light emitting device according to the first embodiment. FIG. 3B is a schematic bottom view of the light emitting device according to the first embodiment. FIG. 3C is a schematic side view of the light emitting device according to the first embodiment. FIG. 4 is a schematic side view of the substrate according to the first embodiment. FIG. 5A is a schematic cross-sectional view of the light emitting device according to the first embodiment and an enlarged view showing the inside of the dotted line portion in an enlarged manner. FIG. 5B is a schematic cross-sectional view of a modified example of the light emitting device according to the first embodiment, and an enlarged view showing the inside of the dotted line portion in an enlarged manner.

Hereinafter, embodiments of the invention will be described with reference to the drawings as appropriate. However, the light emitting device described below is for embodying the technical idea of the present invention, and the present invention is not limited to the following unless otherwise specified. Further, the contents described in one embodiment can be applied to a modified example. Further, the size and positional relationship of the members shown in the drawings may be exaggerated in order to clarify the explanation.

<Embodiment 1>
The light emitting device 1000 according to the embodiment of the present invention will be described with reference to FIGS. 1A to 5B. The light emitting device 1000 includes a light emitting element 20, a light guide member 50, a first wavelength conversion member 31, and a reflecting member 40. The light emitting element 20 has a first surface 201 and a second surface 203 located on the opposite side of the first surface 201. The light guide member 50 covers the side surface 202 of the light emitting element. 1st
The wavelength conversion member 31 covers the first surface 201 of the light emitting element. In addition, the first wavelength conversion member 31
Has a first base material 312 and a first wavelength conversion particle 311. The thickness of the first wavelength conversion member 31 is 60 μm or more and 120 μm or less. The average particle size of the first wavelength conversion particles 311 is 4 μm.
It is 12 μm or less. The central particle size of the first wavelength conversion particles 311 is 4 μm or more and 12 μm or less. The amount of the first wavelength conversion particles 311 is 60% by weight or more and 75% by weight or less with respect to the total weight of the first wavelength conversion member 31. The reflection member 40 covers the side surface of the light emitting element, the side surface of the light guide member, and the side surface of the first wavelength conversion member. Further, the reflective member 40 is in contact with the light emitting element. The light emitting device may include at least one light emitting element. That is, the light emitting device may include only one light emitting element, or may include a plurality of light emitting elements.

The average particle size of the first wavelength conversion particles 311 contained in the first wavelength conversion member 31 is 4 μm or more 1
It is 2 μm or less. When the average particle size of the first wavelength conversion particles 311 is 12 μm or less and the concentrations of the first wavelength conversion particles 311 contained in the first wavelength conversion member 31 are the same, the first base material 312 and the first wavelength The interface with the converted particles 311 can be increased. By increasing the interface between the first base material and the first wavelength conversion particles, the light from the light emitting element is likely to be diffused by the interface between the first base material and the first wavelength conversion particles. As a result, the light from the light emitting element is diffused in the first wavelength conversion member, so that the light distribution chromaticity unevenness of the light emitting device can be suppressed. When the average particle size of the first wavelength conversion particles is 4 μm or more, it becomes easy to extract light from the light emitting element, so that the light extraction efficiency of the light emitting device is improved.

In the present specification, the average particle size of the first wavelength conversion particle 311 is the average value of the particle size measured by the FSSS method (Fisher Sub-Sieve Sizer). The average particle size measured by the Fisher method is, for example, Fisher Sub-
Seeve Sizer Model 95 (manufactured by Fisher Scientific)
Is measured using.

The central particle size of the first wavelength conversion particles 311 included in the first wavelength conversion member 31 is 4 μm or more 1
It is 2 μm or less. When the central particle size of the first wavelength conversion particles is 12 μm or less and the concentration of the first wavelength conversion particles 311 contained in the first wavelength conversion member 31 is the same, the first
The interface between the base material and the first wavelength conversion particles increases. By increasing the interface between the first base material and the first wavelength conversion particles, the light from the light emitting element is likely to be diffused by the interface between the first base material and the first wavelength conversion particles. As a result, the light from the light emitting element is diffused in the first wavelength conversion member, so that the light distribution chromaticity unevenness of the light emitting device can be suppressed. The central particle size of the first wavelength conversion particles is
When it is 4 μm or more, it becomes easy to take out the light from the light emitting element, so that the light taking out efficiency of the light emitting device is improved.

In the present specification, the central particle size of the first wavelength conversion particle 311 is the volume average particle size (median diameter), and the volume accumulation frequency from the small diameter side reaches 50% (D50: median diameter). That is. Laser diffraction type particle size distribution measuring device (MASTER manufactured by MALVERN)
The centriole particle size can be measured by SIZER 2000).

The particle size (D10) at which the volume accumulation frequency of the first wavelength conversion particles from the small diameter side reaches 10% is 6.
It is preferably μm or more and 10 μm or less. The particle size (D90) at which the volume accumulation frequency of the first wavelength conversion particles from the small diameter side reaches 90% is preferably 15 μm or more and 20 μm or less.

The standard deviation (σlog) of the particle size distribution based on the volume of the first wavelength conversion particles is preferably 0.3 μm or less. Since there is little variation in the first wavelength conversion particles, it becomes easy to form the wavelength conversion member 31 having a uniform thickness.

Examples of the first wavelength conversion particles include manganese-activated fluoride-based phosphors. The manganese-activated fluoride-based phosphor is a preferable member from the viewpoint of color reproducibility because it can emit light with a relatively narrow spectral line width.

The thickness of the first wavelength conversion member 31 is 60 μm or more and 120 μm or less. When the thickness of the first wavelength conversion member is 60 μm or more, the number of first wavelength conversion particles 311 that can be contained in the first wavelength conversion member 31 can be increased. When the thickness of the first wavelength conversion member 31 is 120 μm or less, the light emitting device can be made thinner. The thickness of the first wavelength conversion member is the thickness of the first wavelength conversion member in the Z direction.

The first wavelength conversion particle 311 is 60% by weight or more 7 based on the total weight of the first wavelength conversion member 31.
It is 5% by weight or less. Since the content of the first wavelength conversion particles increases when the first wavelength conversion particles are 60% by weight or more with respect to the total weight of the first wavelength conversion member, the first base material and the first wavelength conversion particles The interface with and is increased. By increasing the interface between the first base material and the first wavelength conversion particles, the light from the light emitting element is likely to be diffused by the interface between the first base material and the first wavelength conversion particles. As a result, the light from the light emitting element is diffused in the first wavelength conversion member, so that the light distribution chromaticity unevenness of the light emitting device can be suppressed. When the first wavelength conversion particles are 75% by weight or less with respect to the total weight of the first wavelength conversion member, the ratio of the first base material in the first wavelength conversion member increases, so that the first wavelength conversion member becomes Breaking can be suppressed. The first wavelength conversion member may have only the first wavelength conversion particles as the wavelength conversion particles, or may have wavelength conversion particles made of a material different from the first wavelength conversion particles.

The light emitting device may include a second wavelength conversion member 32 located between the light emitting element 20 and the first wavelength conversion member 31 like the light emitting device 1000 shown in FIG. 2A, and the light emitting device 1000A shown in FIG. 2C. It is not necessary to provide the second wavelength conversion member located between the light emitting element 20 and the first wavelength conversion member 31 as described above. The second wavelength conversion member 32 includes a second base material 322 and a second wavelength conversion particle 321. The average particle size of the first wavelength conversion particles 311 is preferably smaller than the average particle size of the second wavelength conversion particles 321. Since the average particle size of the second wavelength conversion particles is larger than the average particle size of the first wavelength conversion particles, the light from the light emitting element can be easily guided to the second wavelength conversion member 32, so that the light extraction efficiency of the light emitting device Is improved. Further, since the average particle size of the first wavelength conversion particles 311 is smaller than the average particle size of the second wavelength conversion particles 321, the light from the light emitting element is easily diffused in the first wavelength conversion member 31, and the light emitting device. It is possible to suppress unevenness in light distribution chromaticity. The material of the first wavelength conversion particle and the material of the second wavelength conversion particle may be the same or different. Further, the material of the first base material 312 and the material of the second base material 322 may be the same or different. Since the material of the first base material 312 and the material of the second base material 322 are the same, the bonding strength between the first wavelength conversion member 31 and the 22nd wavelength conversion member 32 is improved. 1st
Since the material of the base material 312 and the material of the second base material 322 are different, a difference in refractive index occurs between the first base material 312 and the second base material 322. As a result, the light from the light emitting element is easily diffused at the interface between the first base material 312 and the second base material 322, so that unevenness in the light distribution chromaticity of the light emitting device can be suppressed. The refractive index of the first base material 312 is preferably higher than the refractive index of the second base material 322. By doing so, it is possible to suppress the total reflection of the light from the light emitting element at the interface between the first base material 312 and the second base material 322. As a result, the light extraction efficiency of the light emitting device is improved.

The thickness of the second wavelength conversion member 32 is preferably 20 μm or more and 60 μm or less. When the thickness of the second wavelength conversion member 32 is 20 μm or more, the number of the second wavelength conversion particles 321 that can be contained in the second wavelength conversion member 32 can be increased. When the thickness of the second wavelength conversion member 32 is 60 μm or less, the light emitting device can be made thinner. The thickness of the second wavelength conversion member is the thickness of the second wavelength conversion member in the Z direction.

The thickness of the second wavelength conversion member 32 is preferably less than half the thickness of the first wavelength conversion member 31. By doing so, the light from the light emitting element is more likely to be applied to the first wavelength conversion member 31 than when the second wavelength conversion member 32 is thick. For example, the first wavelength conversion member 31 is 8
In the case of 0 ± 5 μm, the thickness of the second wavelength conversion member 32 is preferably 35 ± 5 μm. The thickness of the covering member 33 that covers the first wavelength conversion member 31, which will be described later, may be the same as that of the first wavelength conversion member 31. For example, the thickness of the first wavelength conversion member 31 is 80.
It may be ± 5 μm, the thickness of the second wavelength conversion member 32 may be 35 ± 5 μm, and the thickness of the covering member 33 may be 80 ± 5 μm. In addition, in this specification, the equivalent thickness means that the variation of about 5 μm is allowed.

The peak wavelength of the light from the second wavelength conversion particles 321 excited by the light emitting element is preferably shorter than the peak wavelength of the light from the first wavelength conversion particles 311 excited by the light emitting element. The peak wavelength of the light from the second wavelength conversion particle 321 excited by the light emitting element is shorter than the peak wavelength of the light from the first wavelength conversion particle 311 excited by the light emitting element, so that the light emitting element is excited. The first wavelength conversion particle can be excited by the light from the second wavelength conversion particle.
This makes it possible to increase the light from the excited first wavelength conversion particles. Since the first wavelength conversion member 31 is arranged on the second wavelength conversion member 32, the light from the second wavelength conversion particle excited by the light emitting element is easily emitted to the first wavelength conversion particle.

The peak wavelength of the light from the first wavelength conversion particle 311 excited by the light emitting element is 610 nm or more and 750 nm or less, and the peak wavelength of the light from the second wavelength conversion particle 321 excited by the light emitting element is 500 nm or more and 570 nm or less. It is preferable to have. By doing so, it is possible to obtain a light emitting device having high color rendering properties. A light emitting element (blue light emitting element) whose emission peak wavelength is in the range of 430 nm or more and 475 nm or less, a first wavelength conversion particle whose peak wavelength of light after being excited by the light emitting element is 610 nm or more and 750 nm or less, and an excitation to the light emitting element. A white light emitting device can be obtained by combining with a second wavelength conversion particle having a peak wavelength of light of 500 nm or more and 570 nm or less. For example, a manganese-activated potassium fluoride silicate phosphor can be mentioned as the first wavelength conversion particle, and a β-sialon-based phosphor can be mentioned as the second wavelength conversion particle. When a phosphor of manganese-activated potassium fluoride silicate is used as the first wavelength conversion particle, it is particularly preferable to include a second wavelength conversion member 32 located between the light emitting element 20 and the first wavelength conversion member 31. .. The first manganese-activated fluoride phosphor
The wavelength conversion particles are likely to cause luminance saturation, but the position of the second wavelength conversion member 32 between the first wavelength conversion member 31 and the light emitting element 20 causes the light from the light emitting element to be excessively converted into the first wavelength conversion particles. It is possible to suppress the irradiation. As a result, deterioration of the first wavelength conversion particles, which are manganese-activated fluoride phosphors, can be suppressed.

As shown in FIG. 2A, the light emitting element 20 includes a first surface 201 and a second surface 203 on the side opposite to the first surface 201. The light emitting element 20 includes at least the semiconductor laminate 23, and the semiconductor laminate 23 is provided with positive and negative electrodes 21 and 22. The positive and negative electrodes 21 and 22 are light emitting elements 20.
It is preferable that the light emitting element 20 is flip-chip mounted on the mounting substrate, which is formed on the same side surface of the above. This eliminates the need for wires that supply electricity to the positive and negative electrodes of the light emitting element, so that the light emitting device can be miniaturized. When the light emitting element is mounted on a flip chip, the positive and negative electrodes 21 and 22 of the light emitting element are located on the second surface 203. In the present embodiment, the light emitting element 20 has the element substrate 24, but the element substrate 24 may be removed.

The light guide member 50 covers the side surface 202 of the light emitting element. The light guide member 50 has a higher transmittance of light from the light emitting element 20 than the reflecting member 40. Therefore, the light guide member 50 is the side surface 2 of the light emitting element.
By covering up to 02, the light emitted from the side surface of the light emitting element 20 can be easily taken out to the outside of the light emitting device through the light guide member 50, so that the light extraction efficiency can be improved. Further, the light guide member 50 may be located between the first surface 201 of the light emitting element and the translucent member 30, and may be located between the first surface 201 of the light emitting element and the translucent member 30. It does not have to be. Since the light guide member is a member that adheres the light emitting element and the translucent member, the light guide member is the first surface 20 of the light emitting element.
By being located between 1 and the translucent member 30, the bonding strength between the light emitting element and the translucent member is improved.

The reflection member 40 covers the side surface of the light emitting element, the side surface of the light guide member, and the side surface of the first wavelength conversion member. By doing so, it is possible to obtain a light emitting device having a high contrast between the light emitting region and the non-light emitting region and having good "parting property". Further, at least a part of the reflective member 40 is in contact with the light emitting element. The light emitting device can be miniaturized by contacting at least a part of the reflecting member 40 with the light emitting element. The reflective member 40 is preferably in contact with the second surface 203 of the light emitting element. By doing so, it is possible to prevent the light from the light emitting element from being absorbed by the substrate on which the light emitting element is mounted.

A covering member 3 that covers the first wavelength conversion member 31 like the light emitting device 1000 shown in FIG. 2A.
3 may be provided. The covering member 33 does not substantially contain wavelength conversion particles. 1st
By providing the covering member 33 that covers the wavelength conversion member 31, even if the first wavelength conversion particles that are sensitive to moisture are used, the covering member 33 also functions as a protective layer, so that deterioration of the first wavelength conversion particles can be suppressed. .. Examples of the wavelength conversion particles that are sensitive to moisture include manganese-activated fluoride phosphors. The manganese-activated fluoride-based phosphor is a preferable member from the viewpoint of color reproducibility because it can emit light with a relatively narrow spectral line width. "Substantially free of wavelength conversion particles" means that wavelength conversion particles inevitably mixed are not excluded, and the content of wavelength conversion particles is preferably 0.05% by weight or less. In the present specification, the first wavelength conversion member 31, the second wavelength conversion member 32, and / or the covering member 33 may be collectively referred to as a translucent member 30.

A coating 34 covering the upper surface of the translucent member 30 as in the light emitting device 1000C shown in FIG. 2D.
May be provided. The coating film 34 is an agglomerate of coating particles, which are nanoparticles. The coating film may be only coating particles, or may contain coating particles and a resin material. Since the refractive index of the coating film is different from the refractive index of the base material of the translucent member located on the outermost surface, it is possible to correct the emission chromaticity of the light emitting device. The base material of the translucent member located on the outermost surface means a base material of a layer that forms a surface of the translucent member opposite to the surface of the light emitting element on the light extraction surface side. For example, coating 3
When the refractive index of 4 is larger than the refractive index of the base material of the translucent member located on the outermost surface, the reflected light component at the interface between the coating film and the air is the base material of the translucent member located on the outermost surface. It increases more than the reflected light component at the interface of air. Therefore, the reflected light component returning to the translucent member can be increased, so that the wavelength conversion particles can be easily excited. Thereby, the emission chromaticity of the light emitting device can be corrected to the long wavelength side. Further, when the refractive index of the coating film 34 is smaller than the refractive index of the base material of the translucent member located on the outermost surface, the reflected light component at the interface between the coating film and the air is the interface between the base material of the translucent member and the air. It is less than the reflected light component in. As a result, the reflected light component returning to the translucent member can be reduced, so that it becomes difficult to excite the wavelength conversion particles. Thereby, the emission chromaticity of the light emitting device can be corrected to the short wavelength side. For example, when a phenyl-based silicone resin is used as the base material of the translucent member located on the outermost surface, titanium oxide, titanium oxide, aluminum oxide, etc. are used as the coating particles for correcting the emission chromaticity of the light emitting device to the long wavelength side. Can be mentioned. When a phenyl-based silicone resin is used as the base material of the translucent member located on the outermost surface, silicon oxide or the like can be mentioned as a film particle for correcting the emission chromaticity of the light emitting device to the short wavelength side. When the light emitting device includes a plurality of translucent members, the upper surface of one translucent member may be coated with a coating film, and the upper surface of the other translucent member may not be coated with a coating film. Whether or not to form a film covering the upper surface of the translucent member can be appropriately selected according to the correction of the emission chromaticity of the light emitting device.
When the light emitting device includes a plurality of translucent members, the upper surface of one of the translucent members is covered with a coating having a refractive index larger than that of the base material of the translucent member located on the outermost surface. The upper surface of the other translucent member may be coated with a coating having a refractive index smaller than that of the base material of the translucent member located on the outermost surface. The material of the coating film that covers the translucent member can be appropriately selected according to the correction of the emission chromaticity of the light emitting device. The coating can be formed by a known method such as potting with a dispenser, spraying with an inkjet or a spray.

The light emitting device may include a substrate 10 on which a light emitting element is placed. For example, the substrate 10 includes a base material 11, a first wiring 12, a second wiring 13, a third wiring 14, and a via 15.
The base material 11 has a front surface 111 extending in the first direction in the longitudinal direction and the second direction in the lateral direction, a back surface 112 located on the opposite side of the front surface, and a bottom surface adjacent to the front surface 111 and orthogonal to the front surface 111. It has 113 and a top surface 114 located on the opposite side of the bottom surface 113. The base material 11 further has at least one recess 16. The first wiring 12 is arranged on the front surface 111 of the base material 11. The second wiring 13 is arranged on the back surface 112 of the base material 11. The light emitting element 20 is the first wiring 12
It is electrically connected to and placed on the first wiring 12. The reflective member 40 covers the side surface 202 of the light emitting element 20 and the front surface 111 of the substrate. At least one recess opens in the back surface 112 and the bottom surface 113. The third wiring 14 covers the inner wall of the recess and is electrically connected to the second wiring. The via 15 is in contact with the first wiring 12 and the second wiring. The via 15 electrically connects the first wiring 12 and the second wiring 13. Further, the via 15 is from the front side 111 to the back side 11 of the base material 11.
It penetrates 2. In the present specification, "orthogonal" means that an inclination of about 90 ° to ± 3 ° is allowed.

The via 15 may be in contact with the third wiring, and the via 15 may be separated from the third wiring. When the via 15 comes into contact with the third wiring, heat from the light emitting element is transferred from the first wiring 12 to the via 1.
Since it can be transmitted to the second wiring 13 and / or the third wiring 14 via 5, the light emitting device 1
The heat dissipation of 000 can be improved. By separating the via 15 from the third wiring, the via and the recess do not overlap in the rear view, so that the strength of the substrate is improved. When there are a plurality of vias 15, one via may be in contact with the third wiring and the other via may be separated from the third wiring.

When the light emitting element 20 is flip-chip mounted on the substrate 10, the positive and negative electrodes 21 and 22 of the light emitting element are connected to the substrate 10 via the conductive adhesive member 60. When the light emitting element 20 is flip-chip mounted on the substrate 10, it is preferable that the first wiring 12 includes a convex portion 121. By locating the positive and negative electrodes 21 and 22 of the light emitting element 20 on the convex portion 121 of the first wiring 12, the positive and negative electrodes 21 and 2 of the first wiring 12 and the light emitting element are located via the conductive adhesive member 60.
When the 2 is connected, the alignment between the light emitting element and the substrate can be easily performed by the self-alignment effect.

The via 15 is preferably circular in the rear view. By doing so, it can be easily formed by a drill or the like. In the present specification, the circular shape includes not only a perfect circle but also a shape close to this (for example, an elliptical shape or a shape in which the four corners of a quadrangle are chamfered into a large arc shape).

The via 15 may be formed by filling the through hole of the base material with a conductive material, and the via 15 may be formed by filling the through hole of the base material with a conductive material.
As shown in A, the fourth wiring 151 covering the surface of the through hole of the base material and the filling member 152 filled in the region surrounded by the fourth wiring 151 may be provided. The filling member 152 may be conductive or insulating. It is preferable to use a resin material for the filling member 152.
Generally, the resin material before curing has higher fluidity than the metal material before curing, so the fourth wiring 151
Easy to fill inside. Therefore, the use of a resin material for the filling member facilitates the manufacture of the substrate. Examples of the resin material that can be easily filled include epoxy resin. When a resin material is used as the filling member, it is preferable to include an additive member in order to reduce the coefficient of linear expansion. By doing so, the difference in the coefficient of linear expansion from the fourth wiring becomes small, so that it is possible to suppress the formation of a gap between the fourth wiring and the filling member due to heat from the light emitting element. Examples of the additive member include silicon oxide. Further, when a metal material is used for the filling member 152, heat dissipation can be improved. Further, when the via 15 is formed by filling the through holes of the base material with a conductive material, it is preferable to use a metal material such as Ag or Cu having high thermal conductivity.

The light emitting device 1000 can be fixed to the mounting substrate by a joining member such as solder formed in the recess 16. The number of recesses provided in the substrate may be one or plural. By having a plurality of recesses, the bonding strength between the light emitting device 1000 and the mounting substrate can be improved. The depth of the recess may be the same on the upper surface side and the bottom surface side, or may be deeper on the bottom surface side than on the top surface side. As shown in FIG. 2B, the depth of the recess 16 in the Z direction is deeper on the bottom surface side than on the top surface side.
In the Z direction, the thickness W1 of the base material located on the upper surface side of the recess can be made thicker than the thickness W2 of the base material located on the bottom surface side of the recess. As a result, it is possible to suppress a decrease in the strength of the base material. Further, since the depth W3 of the recess on the bottom surface side is deeper than the depth W4 of the recess on the top surface side, the volume of the bonding member formed in the recess is increased, so that the bonding strength between the light emitting device 1000 and the mounting substrate is increased. Can be improved. Even in the top light emitting type (top view type) in which the light emitting device 1000 mounts the back surface 112 of the base material 11 and the mounting substrate facing each other, the bottom surface 1 of the base material 11
Even in the side light emitting type (side view type) in which the 13 and the mounting substrate are mounted facing each other, the bonding strength with the mounting substrate can be improved by increasing the volume of the bonding member.

The bonding strength between the light emitting device 1000 and the mounting substrate can be improved particularly in the case of the side light emitting type. Since the depth of the depression in the Z direction is deeper on the bottom surface side than on the top surface side, the area of the opening of the depression on the bottom surface can be increased. By increasing the area of the recess opening on the bottom surface facing the mounting substrate, the area of the joining member located on the bottom surface can also be increased. As a result, the area of the bonding member located on the surface facing the mounting substrate can be increased, so that the bonding strength between the light emitting device 1000 and the mounting substrate can be improved.

The maximum depth of the depression in the Z direction is 0.4 to 0.9 times the thickness of the base material in the Z direction.
It is preferable that it is doubled. When the depth of the recess is deeper than 0.4 times the thickness of the base material, the volume of the bonding member formed in the recess increases, so that the bonding strength between the light emitting device and the mounting substrate can be improved. Since the depth of the recess is shallower than 0.9 times the thickness of the base material, it is possible to suppress a decrease in the strength of the base material.

As shown in FIG. 2B, the recess 16 preferably includes a parallel portion 161 extending from the back surface 112 in a direction parallel to the bottom surface 113 (Z direction). By providing the parallel portion 161 it is possible to increase the volume of the recess even if the area of the opening of the recess on the back surface is the same. By increasing the volume of the recess, the amount of bonding members such as solder that can be formed in the recess can be increased, so that the bonding strength between the light emitting device 1000 and the mounting substrate can be improved. In addition, in this specification, parallel means that an inclination of about ± 3 ° is allowed. Further, in the cross-sectional view, the recess 16 includes an inclined portion 162 that is inclined from the bottom surface 113 in the direction in which the thickness of the base material 11 increases. The inclined portion 162 may be a straight line or a curved portion.

The maximum height of the depression in the Y direction is 0.3 to 0.7 times the thickness of the base material in the Y direction.
It is preferably 5 times. Since the depth of the recess in the Y direction is longer than 0.3 times the thickness of the base material, the volume of the bonding member formed in the recess increases, so that the bonding strength between the light emitting device and the mounting substrate can be improved. it can. Since the length of the recess in the Y direction is shallower than 0.75 times the thickness of the base material, it is possible to suppress a decrease in the strength of the base material.

As shown in FIG. 3A, when there are a plurality of recesses 16 on the back surface, they are preferably located symmetrically with respect to the center line 3C of the base material parallel to the Y direction. By doing so, the self-alignment works effectively when the light emitting device is mounted on the mounting substrate via the bonding member.
The light emitting device can be mounted accurately within the mounting range.

The light emitting device may include an insulating film 18 that covers a part of the second wiring 13. By providing the insulating film 18, it is possible to secure the insulating property on the back surface and prevent a short circuit. In addition, it is possible to prevent the second wiring from being peeled off from the base material.

On the bottom surface, the depth of the depression in the Z direction may be substantially constant, and the depth of the depression may be different between the center and the end. As shown in FIG. 3B, at the bottom surface, the central depth D1 of the recess 16
However, it is preferable that the depth of the depression in the Z direction is the maximum. By doing so, it is possible to increase the thickness D2 of the base material in the Z direction at the end of the recess in the X direction on the bottom surface, so that the strength of the base material can be improved. In the present specification, the center means that a fluctuation of about 5 μm is allowed. The recess 16 can be formed by a known method such as a drill or a laser.

As shown in FIG. 3C, it is preferable that the side surface 403 in the longitudinal direction of the reflecting member 40 located on the bottom surface 113 side is inclined inward of the light emitting device 1000 in the Z direction. By doing so, when the light emitting device 1000 is mounted on the mounting board, the contact between the side surface 403 of the reflective member 40 and the mounting board is suppressed, and the mounting posture of the light emitting device 1000 is likely to be stable. The side surface 404 in the longitudinal direction of the reflective member 40 located on the upper surface 114 side is preferably inclined inward of the light emitting device 1000 in the Z direction. By doing so, the contact between the side surface of the reflective member 40 and the suction nozzle (collet) can be suppressed, and damage to the reflective member 40 at the time of suction of the light emitting device 1000 can be suppressed. As described above, the longitudinal side surface 403 of the reflection member 40 located on the bottom surface 113 side and the longitudinal side surface 404 of the reflection member 40 located on the top surface 114 side of the light emitting device 1000 in the front direction (Z direction) from the back surface. It is preferably inclined inward. The inclination angle θ of the reflective member 40 can be appropriately selected, but from the viewpoint of ease of exerting such an effect and the strength of the reflective member 40, it is preferably 0.3 ° or more and 3 ° or less, preferably 0.5 °.
It is more preferably 2 ° or more, and even more preferably 0.7 ° or more and 1.5 ° or less. Further, it is preferable that the right side surface and the left side surface of the light emitting device 1000 have substantially the same shape. By doing so, the light emitting device 1000 can be miniaturized.

Like the substrate 10 shown in FIG. 4, the first wiring 12 preferably includes a narrow portion having a short length in the Y direction and a wide portion having a long length in the Y direction when viewed from the front. The length D3 of the narrow portion in the Y direction is shorter than the length D4 of the wide portion in the Y direction. The narrow portion is located at a portion that is separated from the center of the via 15 in the X direction in the front view and in which the electrode of the light emitting element is located in the X direction. The wide portion is located at the center of the via 15 in the front view. By providing the first wiring 12 with a narrow portion, it is possible to reduce the area where the conductive adhesive member that electrically connects the electrode of the light emitting element and the first wiring spreads wet on the first wiring. This makes it easier to control the shape of the conductive adhesive member. The peripheral edge of the first wiring may have a rounded corner.

As shown in FIG. 5A, the first wiring, the second wiring, and / or the third wiring may have a wiring main portion 12A and a plating 12B formed on the wiring main portion 12A. In the present specification, the wiring refers to the first wiring, the second wiring, and / or the third wiring. A known material such as copper can be used as the wiring main portion 12A. By having the plating 12B on the wiring main portion 12A, it is possible to improve the reflectance on the surface of the wiring and suppress sulfurization. For example, the nickel plating 120A containing phosphorus may be located on the wiring main portion 12A. Since the hardness of nickel is improved by containing phosphorus, the hardness of the wiring is improved by locating the nickel plating 120A containing phosphorus on the wiring main portion 12A. As a result, it is possible to prevent burrs from being generated in the wiring when the wiring is cut due to the individualization of the light emitting device or the like. The phosphorus-containing nickel plating may be formed by an electrolytic plating method or an electroless plating method.

As shown in FIG. 5A, it is preferable that the gold plating 120B is located on the outermost surface of the plating 12B. Since the gold plating is located on the outermost surface of the plating, the first wiring 12 and the second wiring 1
Oxidation and corrosion on the surface of the 3 and / or the third wiring 14 are suppressed, and good solderability can be obtained. It is possible to improve the reflectance and suppress sulfurization. The gold plating 120B located on the outermost surface of the plating 12B is preferably formed by an electrolytic plating method. The electrolytic plating method can reduce the content of catalytic poisons such as sulfur as compared with the electroless plating method. When the addition reaction type silicone resin using a platinum catalyst is cured at the position where it comes into contact with gold plating,
Since the gold plating formed by the electrolytic plating method contains a small amount of sulfur, it is possible to suppress the reaction between sulfur and platinum. As a result, it is possible to prevent the addition reaction type silicone resin using the platinum-based catalyst from causing curing failure. When forming the gold plating 120B in contact with the nickel plating 120A containing phosphorus, the nickel plating 120A containing phosphorus and the gold plating 120
B is preferably formed by an electrolytic plating method. By forming the plating in the same way,
The manufacturing cost of the light emitting device can be suppressed. The nickel plating may contain nickel, the gold plating may contain gold, and other materials may be contained.

The thickness of the nickel plating containing phosphorus is preferably thicker than the thickness of the gold plating. Since the thickness of the nickel plating containing phosphorus is thicker than the thickness of the gold plating, the first wiring 12 and the second wiring 1
It becomes easy to improve the hardness of the 3 and / or the 3rd wiring 14. The thickness of the nickel plating containing phosphorus is preferably 5 times or more and 500 times or less, and more preferably 10 times or more and 100 times or less the thickness of the gold plating.

As in the light emitting device 1000C shown in FIG. 5B, the wiring includes nickel plating 120C containing phosphorus on the wiring main portion 12A, palladium plating 120D, first gold plating 120E, and second.
The gold plating 120F and the plating 12B in which the gold plating 120F is laminated may be formed. By laminating nickel plating 120C containing phosphorus, palladium plating 120D, first gold plating 120E, and second gold plating 120F, for example, when copper of the wiring main portion 12A is used, plating 12B
It is possible to suppress the diffusion of copper inside. As a result, it is possible to suppress a decrease in the adhesion of each layer of plating. Nickel plating 120C containing phosphorus, palladium plating 120D, and first gold plating 120E are formed on the wiring main portion 12A by the electroless plating method, and the second gold plating 12
0F may be formed by an electrolytic plating method. Second gold plating formed by electroplating 1
Since 20F is located on the outermost surface, it is possible to suppress poor curing of the addition reaction type silicone resin using a platinum-based catalyst.

Hereinafter, each component in the light emitting device according to the embodiment of the present invention will be described.

(Light emitting element 20)
The light emitting element 20 is a semiconductor element that emits light by itself when a voltage is applied, and a known semiconductor element composed of a nitride semiconductor or the like can be applied. The light emitting element 20 includes, for example, an LED.
Tips can be mentioned. The light emitting element 20 includes at least a semiconductor laminate 23, and in many cases further includes an element substrate 24. The top view shape of the light emitting element is preferably a rectangle, particularly a square shape or a rectangular shape long in one direction, but other shapes may be used, and for example, a hexagonal shape can improve the luminous efficiency. The side surface of the light emitting element may be perpendicular to the upper surface, or may be inclined inward or outward. Further, the light emitting element has positive and negative electrodes. Positive and negative electrodes are gold, silver, tin, platinum, rhodium, titanium, aluminum, tungsten,
It can be composed of palladium, nickel or alloys thereof. The emission peak wavelength of the light emitting element can be selected from the ultraviolet region to the infrared region depending on the semiconductor material and its mixed crystal ratio. As the semiconductor material, it is preferable to use a nitride semiconductor, which is a material capable of emitting short-wavelength light capable of efficiently exciting wavelength-converted particles. Nitride semiconductor is mainly general formula In _x
It is represented by Al _y Ga _1-x-y N (0 ≦ x, 0 ≦ y, x + y ≦ 1). The emission peak wavelength of the light emitting element is preferably 400 nm or more and 530 nm or less, more preferably 420 nm or more and 490 nm or less, and more preferably 450 nm or more and 475 nm or less from the viewpoint of luminous efficiency, excitation of wavelength conversion particles and a color mixing relationship with the emission thereof. More preferable. In addition, InAlG
It is also possible to use aAs-based semiconductors, InAlGaP-based semiconductors, zinc sulfide, zinc selenide, silicon carbide and the like. The element substrate of the light emitting element is mainly a crystal growth substrate capable of growing semiconductor crystals constituting the semiconductor laminate, but may be a bonding substrate for joining to a semiconductor element structure separated from the crystal growth substrate. .. Since the element substrate has translucency, it is easy to adopt flip-chip mounting, and it is easy to improve the light extraction efficiency. As a base material for element substrates
Examples thereof include sapphire, gallium nitride, aluminum nitride, silicon, silicon carbide, gallium arsenide, gallium phosphorus, indium phosphorus, zinc sulfide, zinc oxide, zinc selenide and diamond. Of these, sapphire is preferable. The thickness of the element substrate can be appropriately selected, for example, 0.
.. It is preferably 02 mm or more and 1 mm or less, and preferably 0.05 mm or more and 0.3 mm or less from the viewpoint of the strength of the element substrate and / or the thickness of the light emitting device.

(First wavelength conversion member 31)
The first wavelength conversion member is a member provided on the light emitting element. The first wavelength conversion member includes a first base material and first wavelength conversion particles.

(First wavelength conversion particle 311)
The first wavelength conversion particles absorb at least a part of the primary light emitted by the light emitting element and emit secondary light having a wavelength different from that of the primary light. As the first wavelength conversion particle, one of the following specific examples can be used alone or in combination of two or more.

As the first wavelength conversion particle, known wavelength conversion particles such as a wavelength conversion particle that emits green light, a wavelength conversion particle that emits yellow light, and a wavelength conversion particle that emits red light can be used. For example, yttrium aluminum garnet-based phosphors (for example, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce) and lutetium aluminum garnet-based phosphors (for example, Lu ₃ (Al,)) are examples of wavelength-converting particles that emit green light. Ga) ₅ O ₁₂ : Ce), terbium aluminum garnet-based phosphor (for example, Tb ₃ (Al, Ga) ₅ O ₁₂ : Ce) -based phosphor, silicate-based phosphor (for example, (Ba, Sr) ₂ SiO ₄ : Eu), chlorosilicate-based phosphor (
For example, Ca ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu), β-sialon-based phosphor (for example, Si _6)
-Z Al _z O _z N _8-z : Eu (0 <z <4.2)), SGS-based phosphor (for example, SrGa)
₂ S ₄ : Eu) and the like. As the wavelength conversion particles for yellow emission, α-sialon-based phosphors (for example, M _z (Si, Al) ₁₂ (O, N) ₁₆ (where 0 <z ≦ 2 and M is L).
i, Mg, Ca, Y, and lanthanide elements excluding La and Ce) and the like. In addition, among the wavelength conversion particles that emit green light, there are also wavelength conversion particles that emit yellow light. Further, for example, in the yttrium aluminum garnet-based phosphor, the emission peak wavelength can be shifted to the long wavelength side by substituting a part of Y with Gd, and yellow emission is possible. Also,
Among these, there are wavelength conversion particles capable of emitting orange light. As the wavelength conversion particles that emit red light, nitrogen-containing calcium aluminosilicate (CASN or SCANSN) -based phosphors (for example, (
Sr, Ca) AlSiN ₃ : Eu) and the like. In addition, it is a manganese-activated fluoride-based phosphor (general formula (I) A ₂ [M _1-a Mn _a F ₆ ]) (however, in the above general formula (I), A is K, Li, and at least one Na, Rb, selected from the group consisting of Cs and NH _4, M is at least one element selected from the group consisting of group IV and group 14 elements, As for a, 0 <a <0.2 is satisfied)). As a typical example of this manganese-activated fluoride-based phosphor, a manganese-activated potassium fluoride silicate phosphor (
For example, there is K ₂ SiF ₆ : Mn).

(1st base material 312)
The first base material 312 may be any as long as it has translucency with respect to the light emitted from the light emitting element. The "translucency" means that the light transmittance at the emission peak wavelength of the light emitting element is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more. Say that. As the first base material, a silicone resin, an epoxy resin, a phenol resin, a polycarbonate resin, an acrylic resin, or a modified resin thereof can be used. It may be glass. Among them, silicone resin and modified silicone resin are excellent in heat resistance and light resistance, and are preferable. Specific silicone resins include dimethyl silicone resins,
Examples thereof include phenyl-methyl silicone resin and diphenyl silicone resin. In addition, the "modified resin" in this specification shall include a hybrid resin.

The first base material may contain various diffusion particles in the resin or glass. Examples of the diffused particles include silicon oxide, aluminum oxide, zirconium oxide, zinc oxide and the like. As the diffusion particles, one of these can be used alone, or two or more of these can be used in combination. In particular, silicon oxide having a small coefficient of thermal expansion is preferable. Further, by using nanoparticles as diffusion particles, it is possible to increase the scattering of light emitted by the light emitting element and reduce the amount of wavelength conversion particles used.

(Light guide member 50)
The light guide member is a member that adheres a light emitting element and a translucent member to guide the light from the light emitting element to the translucent member. Examples of the base material of the light guide member include silicone resin, epoxy resin, phenol resin, polycarbonate resin, acrylic resin, and modified resins thereof. Among them, silicone resin and modified silicone resin are excellent in heat resistance and light resistance, and are preferable. Specific silicone resins include dimethyl silicone resin, phenyl-methyl silicone resin,
Examples include diphenyl silicone resin. Further, the base material of the light guide member may contain diffusion particles in the same manner as the above-mentioned first base material.

(Reflective member)
From the viewpoint of light extraction efficiency in the Z direction, the reflective member preferably has a light reflectance at the emission peak wavelength of the light emitting element of 70% or more, more preferably 80% or more, and 90% or more. It is even more preferable to have. Further, the reflective member is preferably white. Therefore, it is preferable that the reflective member contains a white pigment in the base material. The reflective member goes through a liquid state before curing. The reflective member can be formed by transfer molding, injection molding, compression molding, potting or the like.

(Base material of reflective member)
Resin can be used as the base material of the reflective member, for example, silicone resin, epoxy resin, etc.
Examples thereof include phenolic resins, polycarbonate resins, acrylic resins, and modified resins thereof. Among them, silicone resin and modified silicone resin have excellent heat resistance and light resistance.
preferable. Specific examples of the silicone resin include dimethyl silicone resin, phenyl-methyl silicone resin, and diphenyl silicone resin.

(White pigment)
White pigments include titanium oxide, zinc oxide, magnesium oxide, magnesium carbonate, magnesium hydroxide, calcium carbonate, calcium hydroxide, calcium silicate, magnesium silicate,
One of barium titanate, barium sulfate, aluminum hydroxide, aluminum oxide, zirconium oxide, and silicon oxide can be used alone or in combination of two or more. The shape of the white pigment can be appropriately selected and may be amorphous or crushed, but spherical is preferable from the viewpoint of fluidity. The particle size of the white pigment is, for example, about 0.1 μm or more and 0.5 μm or less, but the smaller the particle size is preferable in order to enhance the effect of light reflection and coating. The content of the white pigment in the reflective member can be appropriately selected, but from the viewpoint of light reflectivity and viscosity in the liquid state, for example, 10 wt% or more and 80 wt% or less is preferable, 20 wt% or more and 70 wt% or less is more preferable, and 30 wt% or less. % Or more and 60 wt% or less are even more preferable. In addition, "wt%" is a weight percent and represents the ratio of the weight of the material to the total weight of the reflective member.

(Second wavelength conversion member 32)
As the second wavelength conversion member, the same material as the first wavelength conversion member can be used.

(Coating member 33)
As the second wavelength conversion member, the same material as the first base material can be used.

(Board 10)
The substrate 10 is a member on which a light emitting element is placed. The substrate 10 includes the substrate 11 and the first wiring 12
, The second wiring 13, the third wiring 14, and the via 15.

(Base material 11)
The base material 11 can be constructed by using an insulating member such as a resin or a fiber reinforced resin, ceramics, or glass. Examples of the resin or fiber reinforced resin include epoxy, glass epoxy, bismaleimide triazine (BT), and polyimide. Examples of the ceramics include aluminum oxide, aluminum nitride, zirconium oxide, zirconium nitride, titanium oxide, titanium nitride, or a mixture thereof. Among these base materials, it is particularly preferable to use a base material having physical properties close to the coefficient of linear expansion of the light emitting element. The lower limit of the thickness of the base material can be appropriately selected, but from the viewpoint of the strength of the base material, it is preferably 0.05 mm or more, and more preferably 0.2 mm or more. Further, the upper limit of the thickness of the base material is preferably 0.5 mm or less from the viewpoint of the thickness (depth) of the light emitting device, and is 0.
.. It is more preferably 4 mm or less.

(1st wiring 12, 2nd wiring 13, 3rd wiring 14)
The first wiring is arranged in front of the substrate and is electrically connected to the light emitting element. The second wiring is arranged on the back surface of the substrate and is electrically connected to the first wiring via vias. The third wiring covers the inner wall of the recess and is electrically connected to the second wiring. The first wiring, the second wiring and the third wiring are copper, iron, nickel, tungsten, chromium, aluminum, silver, gold, titanium, palladium,
It can be formed of rhodium or an alloy of these. These metals or alloys may be single-layered or multi-layered. In particular, copper or a copper alloy is preferable from the viewpoint of heat dissipation. Further, the surface layer of the first wiring and / or the second wiring is a layer of silver, platinum, aluminum, rhodium, gold or an alloy thereof from the viewpoint of wettability and / or light reflectivity of the conductive adhesive member. May be provided.

(Via 15)
The via 15 is provided in a hole penetrating the front surface and the back surface of the base material 11, and is a member that electrically connects the first wiring and the second wiring. The via 15 is a fourth wiring 1 that covers the surface of the through hole of the base material.
It may be composed of 51 and the filling member 152 filled in 151 in the fourth wiring.
For the fourth wiring 151, the same conductive members as those of the first wiring, the second wiring, and the third wiring can be used. As the filling member 152, a conductive member or an insulating member may be used.

(Insulating film 18)
The insulating film 18 is a member for ensuring insulation on the back surface and preventing a short circuit. The insulating film may be formed of any of those used in the art. For example, a thermosetting resin or a thermoplastic resin can be mentioned.

(Conductive adhesive member 60)
The conductive adhesive member is a member that electrically connects the electrodes of the light emitting element and the first wiring. Conductive adhesive members include bumps such as gold, silver and copper, metal powders such as silver, gold, copper, platinum, aluminum and palladium and metal pastes containing resin binders, tin-bismuth-based and tin-.
Any one of copper-based, tin-silver-based, gold-tin-based solder, and low melting point metal and other brazing materials can be used.

The light emitting device according to the embodiment of the present invention includes a liquid crystal display backlight device, various lighting fixtures, a large display, various display devices such as advertisements and destination guides, a projector device, a digital video camera, a facsimile, and a copier. , Can be used as an image reading device in a scanner or the like.

1000, 1000A, 1000B, 1000C Light emitting device 10 Substrate 11 Base material 12 1st wiring 13 2nd wiring 14 3rd wiring 15 vias
151 4th wiring
152 Filling member 16 Indentation 18 Insulating film 20 Light emitting element 31 First wavelength conversion member 32 Second wavelength conversion member 33 Coating member 34 Coating 40 Reflecting member 50 Light guide member 60 Conductive adhesive member

Claims (8)

A light emitting element having a first surface and a second surface located on the opposite side of the first surface.
A light guide member that covers the side surface of the light emitting element and
A first wavelength conversion member that covers the first surface and has a first base material and first wavelength conversion particles.
A reflection member that covers the side surface of the light emitting element, the side surface of the light guide member, and the side surface of the first wavelength conversion member and is in contact with the light emitting element is provided.
The thickness of the first wavelength conversion member is 60 μm or more and 120 μm or less.
The average particle size of the first wavelength conversion particles is 4 μm or more and 12 μm or less.
The center particle size of the first wavelength conversion particles is 4 μm or more and 12 μm or less.
The first wavelength conversion particles are 60% by weight or more and 75% by weight with respect to the total weight of the first wavelength conversion member.
Light emitting device that is less than% by weight. The light emitting device according to claim 1, wherein the first wavelength conversion particles are manganese-activated fluoride phosphors. The light emitting device according to claim 1 or 2, which is located between the light emitting element and the first wavelength conversion member and includes a second wavelength conversion member including a second base material and second wavelength conversion particles. The light emitting device according to claim 3, wherein the average particle size of the first wavelength conversion particles is smaller than the average particle size of the second wavelength conversion particles. The light emitting device according to claim 3 or 4, wherein the second wavelength conversion particle is a β-sialon-based phosphor. The light emitting device according to any one of claims 3 to 5, wherein the thickness of the second wavelength conversion member is 20 μm or more and 60 μm or less. The light emitting device according to any one of claims 1 to 6, further comprising a covering member that covers the first wavelength conversion member. The light emitting device according to any one of claims 1 to 7, wherein the standard deviation of the particle size distribution based on the volume of the first wavelength conversion member is 0.3 μm or less.

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