JP7464862B2 - Light emitting device, light source - Google Patents

Description

This disclosure relates to light emitting devices and light sources.

There is known a semiconductor light emitting device in which a semiconductor light emitting element is mounted on a circuit board and packaged (see, for example, Patent Document 1). Patent Document 1 describes a semiconductor light emitting element and a light emitting device in which the semiconductor light emitting element is flip-chip mounted and connected to the circuit board via bumps. Since semiconductor light emitting elements are easily damaged by static electricity, they are sometimes mounted on the circuit board together with a protective element. However, when the protective element is flip-chip mounted on the circuit board, the area around the protective element becomes dark, so it is desirable to omit the protective element, and so a protective member that is a varistor made by sintering a paste containing varistor powder is placed between the n-side bump and the p-side bump.

In addition, composite resins capable of forming bypass paths for surges and electronic devices using such composite resins are known (see, for example, Patent Document 2).

Furthermore, nonlinear resistance resin materials are known that have excellent nonlinear resistance characteristics obtained by uniformly dispersing fillers in a matrix resin (see, for example, Patent Document 3).

JP 2012-023328 A JP 2016-134605 A JP 2015-101714 A

The objective of the embodiment of the present disclosure is to provide a light-emitting device or light source that suppresses damage caused by static electricity and has high light extraction efficiency.

The light emitting device according to the embodiment includes a light emitting element having a first surface, a second surface opposite to the first surface, and a side surface connected to the first surface and the second surface, the light reflective portion including a powdered semiconductive material, a powdered light reflective material, and an insulating binder, the semiconductive material having a first powder having at least one shape selected from the group consisting of a sphere, an oval, an ellipsoid, a nearly spherical shape, a nearly oval shape, and a nearly ellipsoid shape, and a second powder having a needle-like shape extending in one or more directions, the light reflective portion being arranged so as to be in contact with each of the pair of element electrodes, the light reflective portion having a light reflectance of 50% or more in a wavelength range of 450 nm to 800 nm, and having varistor characteristics.

Also, a light emitting device according to a different embodiment includes a light emitting element having a first surface, a second surface opposite to the first surface, and a side surface connected to the first surface and the second surface, and a pair of element electrodes having different polarities on the second surface; a first lead frame wiring portion electrically connected to the pair of element electrodes; a second lead frame wiring portion spaced apart from the first lead frame wiring portion; and a light reflecting portion including a powdered semiconductive material, a powdered light reflective material, and an insulating binder, the semiconductive material having a first powder having at least one shape of a sphere, an oblong sphere, an ellipsoid, a substantially spherical shape, a substantially oblong sphere, or a substantially ellipsoid, and a second powder having a needle-like shape extending in one or more directions, the light reflecting portion being arranged so as to be in contact with each of the first lead frame wiring portion and the second lead frame wiring portion, the light reflecting portion having a light reflectance of 50% or more in a wavelength range of 450 nm to 800 nm and having varistor characteristics.

Furthermore, the light source according to the embodiment includes a light emitting element having a first surface, a second surface opposite to the first surface, and a side surface connected to the first surface and the second surface, and having a pair of element electrodes having different polarities on the second surface; a circuit board having at least two wiring parts electrically connected to the pair of element electrodes; and a light reflecting part including a powdered semiconductive material, a powdered light reflective material, and an insulating binder, the semiconductive material having a first powder having at least one shape of a sphere, an oblong sphere, an ellipsoid, a nearly spherical shape, a nearly oblong sphere, or a nearly ellipsoid, and a second powder having a needle-like shape extending in one or more directions, the light reflecting part is arranged so as to be in contact with each of the two wiring parts, and the light reflecting part has a light reflectance of 50% or more in a wavelength range of 450 nm to 800 nm, and has varistor characteristics.

Embodiments of the present disclosure can provide a light-emitting device or light source that suppresses damage caused by static electricity and has high light extraction efficiency.

2 is a schematic bottom view of the light emitting device according to the first embodiment, as viewed from the bottom side. FIG. 1 is a schematic cross-sectional view of a light emitting device according to a first embodiment. FIG. 11 is a schematic bottom view of a light emitting device according to a modified example of the first embodiment, as viewed from the bottom side. 3 is a schematic cross-sectional view illustrating a light reflecting portion according to the first embodiment; FIG. FIG. 11 is a schematic top view of a light emitting device according to a second embodiment, as viewed from the upper surface side. FIG. 11 is a schematic bottom view of the light emitting device according to the second embodiment, as viewed from the bottom side. FIG. 6 is a schematic cross-sectional view of a light emitting device according to a second embodiment. 5A to 5C are schematic cross-sectional views showing a manufacturing process of the light emitting device according to the second embodiment. 5A to 5C are schematic cross-sectional views showing a manufacturing process of the light emitting device according to the second embodiment. 5A to 5C are schematic cross-sectional views showing a manufacturing process of the light emitting device according to the second embodiment. 5A to 5C are schematic cross-sectional views showing a manufacturing process of the light emitting device according to the second embodiment. 5A to 5C are schematic cross-sectional views showing a manufacturing process of the light emitting device according to the second embodiment. 5A to 5C are schematic cross-sectional views showing a manufacturing process of the light emitting device according to the second embodiment. 5A to 5C are schematic cross-sectional views showing a manufacturing process of the light emitting device according to the second embodiment. 5A to 5C are schematic cross-sectional views showing a manufacturing process of the light emitting device according to the second embodiment. 5A to 5C are schematic cross-sectional views showing a manufacturing process of the light emitting device according to the second embodiment. 5A to 5C are schematic cross-sectional views showing a manufacturing process of the light emitting device according to the second embodiment. FIG. 11 is a schematic cross-sectional view of a light emitting device according to a third embodiment. FIG. 13 is a schematic cross-sectional view of a light emitting device according to a modified example of the third embodiment. FIG. 13 is a schematic top view of a light emitting device according to a fourth embodiment. FIG. 11 is a schematic cross-sectional view of a light emitting device according to a fourth embodiment. FIG. 13 is a schematic perspective view of a light source according to a fifth embodiment. FIG. 13 is a schematic cross-sectional view of a light source according to a fifth embodiment. 1 is a schematic cross-sectional view of a circuit board according to an embodiment in which a light reflecting portion is disposed. 1 shows measurement results illustrating current-voltage characteristics of a light emitting device according to an example. FIG. 13 is a diagram showing the light reflectance of a light emitting device according to an example.

The following describes embodiments of the present disclosure with reference to the drawings. However, the embodiments described below are intended to embody the technical ideas of the present disclosure, and unless otherwise specified, the invention is not limited to the following. The contents described in one embodiment are applicable to other embodiments and modified examples. In addition, the drawings are schematic diagrams of the embodiments, and in order to clarify the description, the scale, spacing, positional relationship, etc. of each member may be exaggerated, or some members may be omitted. The directions shown in each figure indicate the relative positions between the components, and are not intended to indicate absolute positions. In addition, the same names and symbols generally indicate the same or similar members, and detailed descriptions will be omitted as appropriate. In addition, in the embodiments, "cover" is not limited to direct contact, but also includes indirect covering, for example, through other members.

<Light-emitting device according to the first embodiment>
The light emitting device of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic bottom view of the light emitting device according to the first embodiment, as viewed from the bottom side. Fig. 2 is a schematic cross-sectional view of the light emitting device according to the first embodiment. Fig. 2 is cut along line II-II in Fig. 1. Fig. 3 is a schematic bottom view of a light emitting device according to a modified example of the first embodiment, as viewed from the bottom side. Fig. 4 is a schematic cross-sectional view illustrating a light reflecting portion according to the first embodiment.

The light emitting device according to the first embodiment includes a light emitting element 10 having a first surface 1, a second surface 2 opposite to the first surface 1, and a side surface 3 connected to the first surface 1 and the second surface 2, and a pair of element electrodes 7 having different polarities on the second surface 2, and a light reflecting portion 20 including a powdered semiconductive material 21, a powdered light reflective material 22, and an insulating binder 23. The semiconductive material 21 has a first powder 21a having at least one shape selected from the group consisting of a sphere, a prolate sphere, an ellipsoid, a substantially spherical shape, a substantially prolate sphere, and a substantially ellipsoid, and a second powder 21b having a needle-like shape extending in one or more directions. The light reflecting portion 20 is arranged so as to contact each of the pair of element electrodes 7, and the light reflecting portion 20 has a light reflectance of 50% or more in a wavelength range of 450 nm to 800 nm, and has varistor characteristics. This makes it possible to provide a light emitting device that suppresses destruction due to static electricity and has high light extraction efficiency. "Varistor characteristics" refers to the "nonlinearity in which the current-voltage characteristics do not follow Ohm's law."

More specifically, the light emitting element 10 has p-type and n-type semiconductor layers 6 arranged on an element substrate 5 such as sapphire. The semiconductor layer 6 is covered with a protective film, but it does not have to be covered. The protective film is an insulating film. For example, an n-type semiconductor layer is provided on the element substrate 5, and a p-type semiconductor layer is formed on the upper surface of the n-type semiconductor layer. The protective film formed on the surface of the n-type semiconductor layer and the p-type semiconductor layer except for the outer peripheral end of the light emitting element 10 has openings in the area occupied by the n-type semiconductor layer and the area occupied by the p-type semiconductor layer. In each opening, the n-type semiconductor layer and the n-side electrode 7a, and the p-type semiconductor layer and the p-side electrode 7b are electrically connected. A light reflecting portion 20 having a varistor function and a light reflecting function is arranged between the n-side electrode 7a and the p-side electrode 7b. The n-side electrode 7a and the p-side electrode 7b are, for example, copper posts formed by electrolytic plating.

The light reflecting portion 20 may be arranged so as to be in contact with each of the pair of element electrodes 7, for example, between the pair of element electrodes 7, or, as shown in a modified example, between the pair of element electrodes 7 and/or at the outer peripheral end of the pair of element electrodes 7. However, as described below, it is sufficient that the light reflecting portion 20 is arranged so as to be in contact with electrodes having different polarities, and it may be arranged between bumps, lead frame wiring portions, wiring portions on the mounting board side, etc., or between these different members.

In a light-emitting device, the varistor characteristics preferably have a nonlinearity coefficient (α) of 3 or more, more preferably 4 or more, and particularly preferably 5 or more. This makes it possible to significantly suppress damage caused by static electricity.

In the light reflecting section 20, it is preferable that the first powder 21a is 30 parts by weight or more and 450 parts by weight or less, and the second powder 21b is 20 parts by weight or more and 200 parts by weight or less, relative to 100 parts by weight of the binder 23. It is more preferable that the first powder 21a is 100 parts by weight or more, and particularly preferably 350 parts by weight or less, relative to 100 parts by weight of the binder 23. This is because the conductivity can be increased by increasing the content of the first powder 21a. It is also more preferable that the second powder 21b is 70 parts by weight or more and 180 parts by weight or less, relative to 100 parts by weight of the binder 23. By setting the first powder 21a and the second powder 21b to the binder 23 within a predetermined range, it is possible to further suppress destruction due to static electricity. In addition, by maintaining an appropriate viscosity in the manufacturing process, it is possible to easily arrange it between a pair of element electrodes 7. By increasing the amount of powder such as the first powder 21a, the second powder 21b, the light reflecting material 22, etc., the varistor characteristics can be improved and the viscosity of the light reflecting portion 20 can be increased. By increasing the viscosity of the light reflecting portion 20, the dispersibility of the powder such as the first powder 21a, the second powder 21b, the light reflecting material 22, etc. can be improved, and the stability and reliability of the varistor characteristics can be improved. If the powder such as the first powder 21a, the second powder 21b, the light reflecting material 22, etc. is unevenly distributed, the varistor characteristics may be reduced or may not be expressed.

The weight ratio of the second powder 21b to the first powder 21a is preferably 4.4% or more and 667% or less, more preferably 30% or more and 240% or less, and particularly preferably 40% or more and 200% or less. This increases the nonlinearity coefficient and significantly suppresses damage caused by static electricity. By blending a predetermined amount of the second powder 21b with the first powder 21a, it is possible to easily form a conductive path. The second powder 21b, which includes a needle-like portion, can easily penetrate between the particles of the first powder 21a, which is spherical or the like, and therefore it is possible to easily form a conductive path.

The light reflecting portion 20 exhibits nonlinearity in the current-voltage characteristic that does not follow Ohm's law. For example, the light reflecting portion 20 includes a binder 23 that is a translucent resin cured product, a plurality of first powders 21a made of semiconductive white zinc oxide (ZnO) powder with a purity of 95% or more dispersed in the binder 23, and a plurality of second powders 21b made of semiconductive white zinc oxide (ZnO) powder dispersed in the binder 23. For example, the first powders 21a are spherical or nearly spherical particles, and the second powders 21b are tetrapod-shaped particles having a needle-like shape extending in four directions. However, some of the needle-like shapes extending in the four directions may crack or chip during the mixing process, resulting in one, two, or three directions, and the length of the needle-like parts may be uneven. In addition, the first powders 21a, the second powders 21b, and the light reflective material 22 may each aggregate, but it is preferable that the aggregates and powders are uniformly dispersed.

The light reflecting portion 20 has a light reflectance of 50% or more in the wavelength range of 450 nm or more and 800 nm or less, and also has varistor properties. By blending a predetermined amount of light reflecting material 22 into the light reflecting portion 20, it is possible to increase the reflectance of light, mainly in the visible light range. On the other hand, if the light reflecting material 22 is insulating, such as an oxide, it is preferable to blend a predetermined amount of light reflecting material 22, since a varistor property cannot be obtained if the blending amount of the light reflecting material 22 is increased.

Each component is explained in detail below.

(Light Emitting Element)
The light emitting element 10 has a first surface 1 which is a light extraction surface, a second surface 2 opposite to the first surface 1, and a side surface 3 connected to the first surface 1 and the second surface 2, and has a pair of element electrodes 7 having different polarities on the second surface 2. The light emitting element 10 is formed in a rectangular parallelepiped shape as an example. The light emitting element 10 is preferably a light emitting diode having an element substrate 5 such as sapphire and a semiconductor layer 6 consisting of an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting layer, and can be selected from those with any wavelength depending on the purpose and use. For example, ZnSe, nitride-based semiconductors (In x Al y Ga 1-X-Y N, 0≦X, 0≦Y, X+Y≦1), GaP, etc. can be used as the light emitting element 10 of purple (light with a peak wavelength of 380 nm to 430 nm), blue (light with a peak wavelength of 430 nm to 490 nm), and green (light with a peak _{wavelength of} 490 _nm to 570 nm).

GaAlAs, AlInGaP, etc. can be used as the light emitting element 10 for red light (light with a wavelength of 620 nm to 750 nm). When making a light emitting device using a phosphor, it is preferable to use a nitride-based semiconductor capable of emitting light with a short wavelength that can efficiently excite the phosphor. The composition, emission color, size, etc. of the light emitting element 10 can be appropriately selected according to the purpose and application.

The element electrodes 7 of the light-emitting element 10 are an n-side electrode 7a and a p-side electrode 7b that are arranged with a gap between them on the second surface 2. The light-emitting element 10 has a conductive member arranged on the pair of element electrodes 7 so that the distance between the second surface 2 of the light-emitting element 10 and the circuit board 70 is equal to or greater than a predetermined distance.

(Light reflecting part)
The light reflecting portion 20 includes a powdered semiconductive material 21, a powdered light reflective material 22, and an insulating binder 23. The semiconductive material 21 has a first powder 21a having at least one of the following shapes: a sphere, an oblong spheroid, an ellipsoid, a substantially spherical shape, a substantially oblong spheroid, and a substantially ellipsoid shape, and a second powder 21b having a needle-like shape extending in one or more directions. The light reflecting portion 20 has a high impedance under normal voltage, but has excellent non-ohmic properties in that it instantly changes from high impedance to low impedance when an overcurrent is applied. By becoming a low impedance, it is possible to pass an overcurrent to the secondary side (such as the ground side), and thereafter has the property of automatically returning to a high impedance immediately.

The diameter or major axis of the first powder 21a is preferably 1 μm to 50 μm, more preferably 5 μm to 30 μm, and particularly preferably 10 μm to 20 μm. By including particles on the order of microns, the electrical resistance can be reduced. In addition, the thickness of the light reflecting section 20 can be reduced by dispersing the first powder 21a without agglomeration. The thickness of the light reflecting section 20 is not particularly limited, but is preferably 10 μm to 70 μm, more preferably 20 μm to 60 μm, and particularly preferably 30 μm to 50 μm. However, it is preferable that the first powder 21a is not agglomerated, but even if it is agglomerated, it can be used as long as it is dispersed within the light reflecting section 20.

The particle size of the first powder 21a is measured using a method conforming to the laser diffraction/scattering method (JIS Z8825), and the value calculated as the number average particle size of each sample can be used.

The second powder 21b preferably has an average fiber length of 1 μm or more and 50 μm or less, more preferably 5 μm or more and 30 μm or less, and particularly preferably 10 μm or more and 20 μm or less. The aspect ratio (number average fiber length/number average fiber diameter) of the second powder 21b is preferably in the range of 1.5 to 5000, more preferably 2 or more, which has better thermal conductivity in the lateral direction of the molded product surface, and even more preferably 10 or more. On the other hand, from the viewpoint of excellent mechanical strength, especially in the weld portion, it is preferably in the range of 1000 or less, more preferably 500 or less, and even more preferably 100 or less.

The number average fiber diameter and number average fiber length of the second powder 21b may be measured by obtaining an SEM image (magnification: 1500x) using a Keyence "Ultra-Deep Multi-Angle Microscope VHX-D500" and randomly selecting 20 fibers from the SEM image.

The semiconductive material 21 is preferably at least one selected from BaTiO ₃ , SrTiO ₃ , ZnO, BiO, CoO, MnO, SbO, CrO, NiO, SiN, and SiO, and is particularly preferably zinc oxide (ZnO). The purity of the zinc oxide is also preferably 90% or more, more preferably 95% or more, and particularly preferably 97% or more. Compared with other oxides, zinc oxide has a very large nonlinear current-voltage characteristic, so it acts as an insulator in areas where the applied voltage is small, and on the other hand, acts as a conductor in areas where the voltage is large. ZnO can realize equal sharing of surge currents and high surface insulation due to improved homogeneity. It is also highly stable and reliable when the circuit voltage is constantly applied. The semiconductive material 21 is preferably 85% by weight or more of zinc oxide, more preferably 90% by weight or more, and particularly preferably 95% by weight or more.

The first powder 21a preferably does not contain Al, Bi, Sb, Co, Mn, or oxides or nitrides containing at least one selected from these, or the content is 0.01% by weight or less. This is because if the first powder 21a contains Al, Bi, or the like, it will be colored and the light reflectance will decrease. For example, if the zinc oxide powder of the first powder 21a contains about 1% Al, it will become conductive and may lead to a short circuit. In addition, the first powder 21a may be colored and the whiteness may decrease. In addition, if it contains a few percent of Al, Bi, Sb, Co, Mn, or the like, these will segregate as oxides at the crystal grain boundaries and the powder itself will have a varistor function, but the powder will become blackened and will not have a light reflectance of 50% or more in the wavelength range of 450 nm to 800 nm.

The second powder 21b preferably has a volume resistivity of 0.1 Ω·cm or more and 1000 Ω·cm or less, more preferably 0.5 Ω·cm or more and 500 Ω·cm or less, and particularly preferably 1 Ω·cm or more and 100 Ω·cm or less. This allows a good conductive path to be formed for discharging surge currents while maintaining the insulation of the light reflecting portion.

The second powder 21b is preferably zinc oxide in the form of tetrapod-type whiskers. The tetrapod-type zinc oxide powder connects the first powders 21a together within the light reflecting portion 20 to form good conductive paths. In addition, even if tetrapod-type whiskers are mixed in high concentration into the light reflecting portion 20, this also has the effect of improving the workability of resin mixing, molding, etc., and the light reflecting portion 20 can have good varistor characteristics and improved light reflection efficiency.

The binder 23 is preferably at least one selected from silicone resin, silicone modified resin, epoxy resin, epoxy modified resin, or a hybrid resin containing at least one of these, glass, or ceramics. Resins such as silicone are inexpensive, easy to work with, and highly translucent. Resins also have good moldability in transfer molding, compression molding, injection molding, screen printing molding, and the like. On the other hand, glass and ceramics have higher heat resistance and light resistance than resins, so they are preferably used in places where heat resistance and light resistance are required.

The light-reflecting material 22 is preferably at least one selected from titanium oxide, barium titanate, aluminum oxide, silicon oxide, barium carbonate, barium sulfate, boron nitride, aluminum nitride, and glass filler. The light-reflecting material 22 does not include semiconductive materials such as zinc oxide. The binder 23 is preferably titanium oxide (TiO ₂ ). Since titanium oxide has a high refractive index, for example, when a resin having a refractive index of 1.40 to 1.60 is used as the binder 23, the difference in refractive index is increased by using titanium oxide having a refractive index of 2.70, and the light reflectance is improved. The particle size (median size) of the light-reflecting material 22 is not particularly limited, but is preferably 0.1 μm to 5 μm, more preferably 0.15 μm to 1 μm, and particularly preferably 0.2 μm to 0.4 μm.

The light reflecting portion 20 may further contain either fumed silica or higher fatty acid amide. By containing these, it is possible to prevent the first powder 21a, the second powder 21b, and the light reflective material 22 from settling or agglomerating in the light reflecting portion and to promote uniform dispersion.
The light reflecting portion 20 preferably further contains at least one coupling agent selected from aluminate, silane, titanate, and zirconate. This is because adding a coupling agent to the binder 23 can improve the wettability of each of the first powder 21a, the second powder 21b, and the light reflecting substance 22. In addition, the coupling agent may be subjected to a surface modification treatment before mixing the first powder 21a, the second powder 21b, and the light reflecting substance 22 with the binder 23.

It is preferable that the light reflecting section ²⁰ further contains an ion-trapping powder. With this, when impurities such as Na ⁺ , K ⁺ , _SO42- , and ^NO3- are contained in the light reflecting section 20, the impurity ions can be trapped to prevent deterioration of the leak characteristics of the light reflecting section 20 and inhibition of curing of the resin. It is preferable that the ion-trapping powder is an inorganic ion trapping agent such as a Zr-based, Bi-based, Bi, Sb-based, Mg, Al, Zr-based, or Bi, Zr-based agent. It is preferable that the primary particle diameter of the ion-trapping powder is 1 μm or less, preferably 800 nm or less, and more preferably 500 nm or less.

The light reflecting section 20 may further include conductive particles. By incorporating a small amount of conductive particles in the light reflecting section 20, the content of the first powder 21a and the second powder 21b can be reduced. The conductive particles may be present in an amount of 10 parts by weight to 40 parts by weight, or 13 parts by weight to 35 parts by weight, per 100 parts by weight of the binder.

(Method of manufacturing the light emitting device according to the first embodiment)
Next, a method for manufacturing the light emitting device according to the first embodiment will be outlined.

After preparing a light-emitting element 10 having a pair of element electrodes 7, a light reflecting portion 20 is placed between the pair of element electrodes 7.

In preparation, the pair of element electrodes 7 are plated using electrolytic plating or the like.

In the arrangement, the light reflecting portion 20 is arranged between a pair of element electrodes 7 by screen printing, compression molding, or the like. The light reflecting portion 20 is in contact with each of the n-side electrode 7a and the p-side electrode 7b. The binder 23 of the light reflecting portion 20 is then solidified or hardened. For example, when the n-side electrode 7a and the p-side electrode 7b are entirely covered with the binder 23, the surface of the light reflecting portion 20 is ground with a backside grinder or the like so that the surfaces of the n-side electrode 7a and the p-side electrode 7b are exposed. As a result, the n-side electrode 7a and the p-side electrode 7b are exposed from the light reflecting portion 20.

Next, the assembly of light-emitting devices is cut with a dicing blade or laser light to separate them into individual light-emitting devices. The light-emitting device may be a single-chip structure including one n-type and one p-type semiconductor layer, or a multi-chip structure including multiple n-type and p-type semiconductor layers.

The light-emitting device manufactured in this manner emits light when a current is supplied to the semiconductor layer 6 through the n-side electrode 7a and the p-side electrode 7b. The light emitted from the semiconductor layer 6 is mainly transmitted through the first surface 1 and emitted to the outside. This makes it possible to suppress damage caused by static electricity and to provide a light-emitting device with high light extraction efficiency.

<Light-emitting device according to the second embodiment>
The light emitting device according to the second embodiment will be described with reference to the drawings. Fig. 5 is a schematic top view of the light emitting device according to the second embodiment as viewed from the top surface side. Fig. 6 is a schematic bottom view of the light emitting device according to the second embodiment as viewed from the bottom surface side. Fig. 7 is a schematic cross-sectional view of the light emitting device according to the second embodiment. Fig. 7 is cut along line VII-VII in Fig. 5.

The light emitting device according to the second embodiment is provided with a wavelength conversion member 40 facing the first surface 1 of the light emitting element 10, compared to the light emitting device according to the first embodiment. An adhesive 50 is disposed between the first surface 1 of the light emitting element 10 and the wavelength conversion member 40, and fixes the light emitting element 10 and the wavelength conversion member 40. In addition, an adhesive 50 that forms a fillet of a substantially triangular shape in cross section is also disposed on the side surface 3 of the light emitting element 10, and is continuous with the adhesive 50 disposed between the first surface 1 of the light emitting element 10 and the wavelength conversion member 40. The light reflecting portion 20 is disposed on the side of the side surface 3 of the light emitting element 10 and continuous with the second surface 2 of the light emitting element 10. The light reflecting portion 20 is also disposed between the pair of element electrodes 7 and on the outer peripheral end portion of the pair of element electrodes 7. The rest is generally the same as the light emitting device according to the first embodiment, so a description will be omitted. By adopting such a configuration, it is possible to provide a varistor function, and the light emitted laterally from the light emitting element 10 can be reflected by the light reflecting portion 20 disposed on the side of the light emitting element 10, thereby improving the light extraction upward from the light emitting device. The varistor function can also be enhanced because the light reflecting portion 20 and the pair of element electrodes 7 are in contact not only between the pair of element electrodes 7 but also at the outer peripheral ends of the pair of element electrodes 7. This light emitting device can be used as a CSP (Chip Size Package) type light emitting device.

The light reflecting section 20 may be disposed not only on the side of the side surface 3 of the light emitting element 10, but also directly on the side surface 3 of the light emitting element 10. The light reflecting section 20 may also be disposed on the side surface or side surface of the wavelength conversion member 40. By disposing the light reflecting section 20 on the side surface or side surface of the wavelength conversion member 40, a light emitting device with good contrast can be provided.

(Wavelength conversion member)
The wavelength conversion member contains a phosphor. The wavelength conversion member may contain an inorganic material. The wavelength conversion member preferably contains a ceramic composite containing a phosphor and an inorganic material. The wavelength conversion member may be a single layer of a phosphor layer made of a ceramic composite containing a phosphor and an inorganic material, or may be a laminate of a phosphor layer made of a ceramic composite containing a phosphor and an inorganic material and a translucent layer made of at least one material selected from the group consisting of resin, glass, and inorganic substances. The ceramic composite containing a phosphor and an inorganic material may contain one type of first phosphor, or may contain another type of second phosphor having a different composition from the first phosphor. The first phosphor layer may be a first ceramic composite containing one type of first phosphor and an inorganic material, and the second phosphor layer may be a second ceramic composite containing another type of second phosphor and an inorganic material having a different composition from the first phosphor, and a translucent layer not containing a phosphor may be laminated. The translucent layer may be a plate-shaped body made of an inorganic oxide similar to the inorganic oxide contained in the ceramic composite described later.

It is preferable that the phosphor contained in the wavelength conversion member includes a rare earth aluminate phosphor, and the inorganic material includes an inorganic oxide. Examples of phosphors include yttrium aluminum garnet phosphors (e.g., _Y3 ( _Al ,Ga) _5O12 :Ce), lutetium aluminum garnet phosphors (e.g., _Lu3 (Al,Ga _{)5O12 :} Ce), terbium aluminum garnet phosphors (e.g., _Tb3 (Al, _{Ga)5O12 :} Ce), CCA phosphors (e.g., _Ca10 ( _PO4 ) _6Cl2 :Eu), SAE phosphors (e.g. _{, Sr4Al14O25 :} Eu), chlorosilicate phosphors (e.g. _{, Ca8MgSi4O16Cl2 :} Eu), β- _sialon phosphors (e.g., (Si,Al) ₃ (O,N _{) 4} oxynitride phosphors such as Ca(Si,Al) ₁₂ (O,N) _{16:Eu) or α-sialon phosphors (for example, Ca(Si,Al)12(O,N)16 :} Eu), nitride phosphors such as SLA phosphors (for example, _SrLiAl3N4 :Eu), CASN phosphors (for example, _CaAlSiN3 :Eu) or SCASN phosphors (for example, ₍ Sr,Ca) _AlSiN3 : _Eu ), KSF phosphors (for example, _K2SiF6 :Mn), KSAF phosphors ₍ for example, _{K2Si0.99Al0.01F5.99} : _Mn ) or MGF phosphors ₍ for example, _{3.5MgO.0.5MgF2.GeO2} Fluoride-based phosphors such as CsPb(F,Cl,Br,I) 3 , phosphors having a perovskite structure (e.g., CsPb(F,Cl,Br,I) ₃ ), or quantum dot phosphors (e.g., CdSe, InP, AgInS ₂ or AgInSe ₂ ) can be used.

The KSAF phosphor may have a composition represented by the following formula (I).
_{M2 [ SipAlqMnrFs ]} ( _I )

In formula (I), M represents an alkali metal and may contain at least K. Mn may be a tetravalent Mn ion. p, q, r, and s may satisfy 0.9≦p+q+r≦1.1, 0<q≦0.1, 0<r≦0.2, and 5.9≦s≦6.1. Preferably, 0.95≦p+q+r≦1.05 or 0.97≦p+q+r≦1.03, 0<q≦0.03, 0.002≦q≦0.02, or 0.003≦q≦0.015, 0.005≦r≦0.15, 0.01≦r≦0.12, or 0.015≦r≦0.1, and 5.92≦s≦6.05 or 5.95≦s≦6.025. For example, compositions represented by K ₂ [Si _0.946 Al _0.005 Mn _0.049 F _5.995 ], K ₂ [Si _0.942 Al _0.008 Mn _0.050 F _5.992 ], and K ₂ [Si _0.939 Al _0.014 Mn _0.047 F _5.986 ] can be mentioned. According to such a KSAF-based phosphor, red light emission with high brightness and narrow half-width of the emission peak wavelength can be obtained. In this specification, in the composition formula showing the composition of the phosphor, a plurality of elements described separated by a comma (,) means that at least one element of these plurality of elements is contained in the composition formula, and two or more elements may be combined and contained. In addition, in the formula showing the composition of the phosphor, the part before the colon (:) represents the elements constituting the host crystal and their molar ratio, and the part after the colon (:) represents the activation element. "Molar ratio" refers to the molar amount of an element in one mole of the phosphor composition.

The inorganic oxide contained in the wavelength conversion member is preferably an inorganic oxide having translucency that transmits light from the light emitting element and light wavelength-converted by the phosphor. Examples of inorganic oxides include at least one inorganic oxide selected from the group consisting of SiO ₂ , Al ₂ O ₃ , ZrO ₂ , MgO, TiO ₂ , CeO ₂ , ZnO, SnO ₂ and Y ₂ O _3. In this specification, translucency means that 60% or more of the light emitted from the light emitting element and the light wavelength-converted by the phosphor are transmitted, and examples of the translucent material may include those having a transmittance of 70% or more, 80% or more, or 90% or more of the light emitted from the light emitting element. When the phosphor contained in the ceramic composite is a rare earth aluminate phosphor, the inorganic material preferably contains Al ₂ O ₃ .

The wavelength conversion member 40 does not need to be 100% phosphor, but may be a mixture of phosphor and a material with good thermal conductivity such as aluminum oxide at 0.01% by weight to 10% by weight. It may also be a phosphor layer disposed on a light-transmitting member such as glass or ceramics. The phosphor can be disposed on the light-transmitting member by printing, dispensing, or other methods.

(glue)
The adhesive 50 is arranged so that a part of it forms an adhesive layer that bonds the wavelength conversion member 40 and the light emitting element 10, and the other part forms a fillet. As the adhesive 50 that constitutes the fillet, it is preferable to use a light-transmitting material that can effectively guide the light emitted from the light emitting element 10 to the wavelength conversion member 40 and optically connect the light emitting element 10 and the wavelength conversion member 40. As the adhesive 50, for example, an organic resin such as an epoxy resin, a silicone resin, a phenolic resin, or a polyimide resin can be used, and it is preferable to use a silicone resin with high heat resistance. In addition, the thinner the thickness of the adhesive layer formed between the light emitting element 10 and the wavelength conversion member 40, the better, and this improves heat dissipation and reduces the loss of light that passes through the adhesive 50 between the light emitting element 10 and the wavelength conversion member 40, thereby improving the light output of the light emitting device. In addition, it is preferable that the refractive index of the adhesive 50 is smaller than that of the light emitting element 10 and higher than that of the wavelength conversion member 40. By making the refractive indexes have a predetermined relationship, the light emitted from the light emitting element 10 can be efficiently released to the outside through the adhesive 50 and the wavelength conversion member 40.

The adhesive 50 is disposed between the lower peripheral edge of the wavelength conversion member 40 and the side surface 3 of the light-emitting element 10. The fillet is preferably disposed so that the outer outline is a substantially straight line or a convex curve when viewed in cross section toward the outside, but may be a concave curve. Furthermore, the fillet is disposed so as to cover a part or all of the side surface 3 of the light-emitting element 10.

A fillet can be formed by extending the excess adhesive 50, other than the amount of adhesive layer required to bond the wavelength conversion member 40 to the first surface 1 of the light emitting element 10, to the side surface 3 of the light emitting element 10. The triangular cross section of the fillet is formed in a position where the bottom surface of the wavelength conversion member 40 and the side surface 3 of the light emitting element 10 intersect at right angles, continuing from the adhesive layer. This triangular cross section of the fillet can be formed by optimizing the wettability and viscosity of the silicone resin or the like with the side surface 3 of the light emitting element 10 and the bottom surface of the wavelength conversion member 40.

(Method of manufacturing the light emitting device according to the second embodiment)
Next, a method for manufacturing the light emitting device according to the second embodiment will be described with reference to the drawings. Figures 8 to 17 are schematic cross-sectional views showing the manufacturing process of the light emitting device according to the second embodiment.

First, a translucent sheet 63 and a phosphor sheet 64 are attached to a metal plate 61 using double-sided tape 62. Either sheet may be used depending on the purpose. The phosphor sheet 64 will eventually become the wavelength conversion member 40 after being singulated.

Next, half-cut grooves are made in parts of the phosphor sheet 64 and the translucent sheet 63 using a dicing blade A. These grooves are formed partway through the translucent sheet 63.

Next, the first surface 1 of the light-emitting element 10 and the phosphor sheet 64 are bonded to face each other using adhesive 50. In this case, the light-emitting element 10 is positioned at the center of the wavelength conversion member 40 due to the self-alignment effect in the groove portion of the phosphor sheet 64, and a fillet is formed on the side surface 3 of the light-emitting element 10 by the adhesive 50.

Next, the light reflecting portion 20 is placed on the side of the light emitting element 10. At this time, the light reflecting portion 20 is placed so as to cover the pair of element electrodes 7 provided on the second surface 2 of the light emitting element 10. The light reflecting portion 20 is also placed on the surface of the adhesive 50 and in the groove of the phosphor sheet 64. This placement method may be transfer molding, compression molding, injection molding, screen printing molding, dispensing, spraying, etc. The placed light reflecting portion 20 is solidified or hardened. The mold temperature in compression molding is preferably near the hardening temperature of the resin, for example, a mold temperature between -30°C and 50°C lower than the hardening temperature of the resin. For example, if the hardening temperature of the resin is 130°C, the mold temperature is 120°C or higher and 140°C or lower. The hardening temperature is 30 seconds or higher and 30 minutes or lower, preferably 1 minute or higher and 10 minutes or lower. The resin may be hardened in two stages, i.e., primary hardening and secondary hardening, or may be hardened in one stage. The light reflecting portion 20 can be easily solidified by solidifying or hardening resin, glass, ceramics, etc. In particular, the light reflecting portion 20 can be formed without undergoing a process such as sintering at 1000°C or higher.

Next, the light reflecting portion 20 is ground so that the pair of element electrodes 7 are exposed.

Next, the pair of element electrodes 7 exposed by grinding are coated with a sputtered film of gold or the like, and the rest of the electrodes are removed with a laser to form the coating 7c. This makes it possible to prevent discoloration of the copper base material of the pair of element electrodes 7.

Next, a half-cut groove is formed in the groove portion of the phosphor sheet 64 between adjacent light-emitting elements 10 using a dicing blade B.

After the grooves are formed, the metal plate 61 is peeled off from the double-sided tape 62.

Finally, the light-emitting device according to the second embodiment can be manufactured by grinding all of the translucent sheet 63 and part of the phosphor sheet 64 to expose the half-cut grooves and separate each light-emitting device. When separated into individual pieces, the phosphor sheet 64 corresponds to a wavelength conversion member. However, it is also possible to grind only part of the translucent sheet 63 without grinding the phosphor sheet 64, to produce a light-emitting device having a translucent member.

(Light emitting device according to the third embodiment)
The light emitting device according to the third embodiment will be described with reference to the drawings. Fig. 18 is a schematic cross-sectional view of the light emitting device according to the third embodiment. Descriptions of parts having the same configuration as the light emitting device according to the first embodiment and the light emitting device according to the second embodiment may be omitted.

A light-emitting element 10 having a first surface 1, a second surface 2 opposite to the first surface 1, and a side surface 3 connected to the first surface 1 and the second surface 2, and having a pair of element electrodes 7 having different polarities on the second surface 2, a first lead frame wiring portion 8a electrically connected to the pair of element electrodes 7, a second lead frame wiring portion 8b spaced apart from the first lead frame wiring portion 8a, and a light-reflecting portion 20 including a powdered semiconductive material 21, a powdered light-reflecting material 22, and an insulating binder 23, The conductive material 21 has a first powder 21a having at least one of the shapes of a sphere, a long sphere, an ellipsoid, a substantially spherical shape, a substantially long sphere, and a substantially ellipsoid, and a second powder 21b having a needle-like shape extending in one or more directions. The light reflecting portion 20 is arranged so as to contact each of the first lead frame wiring portion 8a and the second lead frame wiring portion 8b. The light reflecting portion 20 has a light reflectance of 50% or more in a wavelength range of 450 nm to 800 nm and has varistor characteristics. The pair of element electrodes 7 are electrically connected to the first lead frame wiring portion 8a and the second lead frame wiring portion 8b, respectively, but may be arranged via a conductive member such as a wire or solder, or may be directly connected. The package 8 has the first lead frame wiring portion 8a and the second lead frame wiring portion 8b fixed by a fixing portion 8c made of resin, ceramics, or the like. The package 8 has a recess having a bottom plane and a side surface, and the light emitting element 10 is mounted face-up on the bottom plane of the recess. The light emitting element 10 is sealed with a translucent sealing member 8d containing a phosphor. The light reflecting portion 20 may be arranged so as to be in contact with each of the first lead frame wiring portion 8a and the second lead frame wiring portion 8b, and may be arranged, for example, on the first lead frame wiring portion 8a and the second lead frame wiring portion 8b and the fixed portion 8c that constitute the bottom plane of the recess of the package 8. This can suppress the light emitted from the light emitting element 10 from being emitted to the back side of the package 8 through the fixed portion 8c between the first lead frame wiring portion 8a and the second lead frame wiring portion 8b, and can improve the light extraction to the front side of the package 8. The light reflecting portion 20 is formed in a shape that follows the outer edge of the first lead frame wiring portion 8a and the second lead frame wiring portion 8b on the fixed portion 8c, for example, in a straight line. In addition, the width of the light reflecting portion 20 is preferably 1.1 times or more and 3 times or less than the width of the first lead frame wiring portion 8a and the second lead frame wiring portion 8b. In addition, the light reflecting portion 20 may be one in which the first powder 21a, the second powder 21b, and the light reflecting material 22 are concentrated in the binder 23, but the first powder 21a, the second powder 21b, and the light reflecting material 22 may be precipitated or centrifuged after the light reflecting portion 20 is placed. This allows the thickness of the light reflecting portion 20 to be uniform and the light reflection efficiency to be high. The light emitting element 10 is mounted on the bottom plane of the recess of the package 8 via a metal member such as solder or an adhesive 50 such as resin. If resin is used for the adhesive 50 and also for the light reflecting portion 20, the adhesive 50 and the light reflecting portion 20 can be made more adhesive because they are made of the same material.

The light emitting device according to the third embodiment differs from the light emitting device according to the first embodiment in that the light emitting element 10 is arranged in a package 8. The embodiment of the light emitting element 10 has also changed from face down to face up. A pair of element electrodes 7 are connected to the first lead frame wiring portion 8a and the second lead frame wiring portion 8b via wires. Furthermore, the light reflecting portion 20 is arranged on the bottom plane of the recess. In particular, the light reflecting portion 20 is arranged so as to be in contact with the first lead frame wiring portion 8a and the second lead frame wiring portion 8b.

The light emitting device according to the modified example of the third embodiment will be outlined with reference to the drawings. FIG. 19 is a schematic cross-sectional view of the light emitting device according to the modified example of the third embodiment. The light emitting device according to the modified example of the third embodiment is generally the same as the light emitting device according to the third embodiment except for the shape of the light reflecting portion, so an explanation of the parts having the same configuration will be omitted.

The light reflecting portion 20 is disposed on the entire bottom surface of the recess, except for the portion where the light emitting element 10 is mounted. The light reflecting portion 20 may exclude not only the portion where the light emitting element 10 is mounted, but also the connection portion between the conductive member such as a wire and the first lead frame wiring portion 8a, etc. Furthermore, the light reflecting portion 20 may be disposed on the entire bottom surface of the recess by using partial or multiple arrangement of the light reflecting portion 20. This not only prevents the light emitted from the light emitting element 10 from passing through the fixing portion 8c between the first lead frame wiring portion 8a and the second lead frame wiring portion 8b and being emitted to the back side of the package 8, but also improves the light reflectance and varistor characteristics.

(Light emitting device according to the fourth embodiment)
The light emitting device according to the fourth embodiment will be outlined with reference to the drawings. Fig. 20 is a schematic top view of the light emitting device according to the fourth embodiment. Fig. 21 is a schematic cross-sectional view of the light emitting device according to the fourth embodiment, taken along line XXI-XXI in Fig. 20. Explanations of parts having the same configuration as the light emitting devices according to the first to third embodiments may be omitted.

The light emitting device according to the fourth embodiment may be provided with a first wiring portion 9a and a second wiring portion 9b on a substrate 9c, and may be used as a circuit substrate. In the light emitting element 10, a semiconductor layer 6 is disposed on an element substrate 5, and an n-side electrode 7a and a p-side electrode 7b are disposed on the semiconductor layer 6. A wavelength conversion member 40 is disposed on the element substrate 5 on the side opposite to the side on which the semiconductor layer 6 is disposed. An adhesive 50 is disposed between the element substrate 5 and the wavelength conversion member 40, and the wavelength conversion member 40 is fixed to the element substrate 5. A translucent member 42 is disposed on the wavelength conversion member 40. The light emitting element 10 is flip-chip mounted on the substrate 9c, and the n-side electrode 7a and the p-side electrode 7b of the light emitting element 10 are electrically connected to the first wiring portion 9a and the second wiring portion 9b directly or via solder or a metal layer. The light reflecting portion 20 is disposed between the n-side electrode 7a and the p-side electrode 7b, between the first wiring portion 9a and the second wiring portion 9b, on the side or side of the semiconductor layer 6, on the side or side of the element substrate 5, and on the side or side of the wavelength conversion member 40, but may be disposed partially as long as it is disposed to connect different electrodes. The light reflecting portion 20 may be formed by transfer molding, compression molding, or the like. When the light reflecting portion 20 is provided between the first wiring portion 9a and the second wiring portion 9b, a protrusion is formed on the substrate 9c by plating or the like, the light reflecting portion 20 is disposed on the substrate 9c other than the protrusion, and the protrusion is exposed by grinding or the like to form the first wiring portion 9a and the second wiring portion 9b. After that, the light reflecting portion 20 may be disposed on the substrate 9c after disposing the light emitting element 10. The distance between the first wiring portion 9a and the second wiring portion 9b is preferably 0.15 mm or more and 0.25 mm or less, and the height of the protrusion of the wiring portion is preferably 25 μm or more and 50 μm or less, but is not limited thereto.

The manufacturing method of the light emitting device according to the fourth embodiment can be described above and by referring to Japanese Patent No. 6217705.

(Light source according to the fifth embodiment)
The light source according to the fifth embodiment will be briefly described with reference to the drawings. Fig. 22 is a schematic perspective view of the light source according to the fifth embodiment. Fig. 23 is a schematic cross-sectional view of the light source according to the fifth embodiment, taken along line XXIII-XXIII in Fig. 22.

The light source has a first surface 1, a second surface 2 opposite to the first surface 1, and a side surface 3 connected to the first surface 1 and the second surface 2. The light source comprises a light-emitting element 10 having a pair of element electrodes 7 having different polarities on the second surface 2, a circuit board 70 having at least two wiring parts electrically connected to the pair of element electrodes 7, and a light-reflecting part 20 including a powder-like semiconductive material 21, a powder-like light-reflecting material 22, and an insulating binder 23. The semiconductive material 21 has a first powder 21a having at least one shape selected from the group consisting of a sphere, an oval, an ellipsoid, a nearly spherical, a nearly oval, and a nearly ellipsoid, and a second powder 21b having a needle-like shape extending in one or more directions. The light-reflecting part 20 is arranged so as to be in contact with each of the two wiring parts. The light-reflecting part 20 has a light reflectance of 50% or more in a wavelength range of 450 nm to 800 nm, and has varistor characteristics. At least two wiring parts include a first wiring part 9a and a second wiring part 9b. The circuit board 70 includes a first wiring part 9a and a second wiring part 9b on a substrate 9c. The pair of element electrodes 7 have different polarities of an n-side electrode 7a and a p-side electrode 7b, and the n-side electrode 7a and the p-side electrode 7b are electrically connected to the first wiring part 9a and the second wiring part 9b, respectively. The light reflecting part 20 is disposed between the pair of element electrodes 7 and between the first wiring part 9a and the second wiring part 9b. The light reflecting part 20 includes a wavelength conversion member 41 and a light-transmitting member 42 that are disposed on the first surface 1 of the light emitting element 10 and convert the wavelength of light from the light emitting element 10. An adhesive 50 is disposed between the first surface 1 of the light emitting element 10 and the wavelength conversion member 41, and on the side surface 3 of the light emitting element 10. The adhesive 50 is disposed on the side of the light emitting element 10 so as to cover a part of the light reflecting part 20. A light reflecting layer 43 containing a light reflective material such as titanium oxide is formed on the light reflecting part 20. Furthermore, a hemispherical lens 44 is arranged so as to be in contact with the light-transmitting member 42 and the light-reflecting layer 43. The light-reflecting portion 20 is used like an underfill, but even if it is given a certain fluidity, it has varistor characteristics and a certain light reflectance because the binder 23 contains a certain amount of the first powder 21a, the second powder 21b, and the light-reflecting material 22.

The light reflecting unit and light emitting device according to the embodiment are described below.

(Adjustment of light reflecting part)
The light reflecting portion includes a powdered semiconductive material, a powdered light reflective material, and an insulating binder. The semiconductive material has a first powder having a spherical or nearly spherical shape, and a second powder having a needle-like shape extending in four directions.

Phenyl silicone resin (DuPont Toray Specialty Materials, Dow Corning: product model number OE7660) is used as the binder, zinc oxide (ZnO) is used as the first powder, tetrapod-type zinc oxide (ZnO) (Panasonic: Pana-Tetra zinc oxide single crystal) is used as the second powder, titanium oxide (TiO ₂ ) is used as the light reflective material, zinc oxide (ZnO) (Otowa Electric Industry Co., Ltd.) is used as the colored microvaristor material, and a silane coupling agent (Shin-Etsu Silicone: product model number KBM-1083) is used as the coupling agent. Table 1 shows the blending ratio and physical property values of these powders. These powders can be mixed using known mixers such as a rotation-revolution mixer, a dissolver, a three-roll mill, a rotary mixer, and a two-shaft mixer.

In the examples and comparative examples, the phenyl silicone resin and the silane coupling agent are mixed in advance, and then mixed using a planetary centrifugal mixer (Thinky Planetary centrifugal mixer, product name ARV-310LED) at a rotation speed of 1200 rpm for a mixing time of approximately 3 minutes. After that, a specified amount of powder is mixed and mixed for approximately 3 minutes, after which the mixture is kneaded using the planetary centrifugal mixer for approximately 3 minutes.

(Sealing between electrodes)
The composition of the light reflecting portion is used to perform interelectrode sealing. In order to confirm the varistor characteristics and light reflectance when the light reflecting portion is disposed between a pair of element electrodes, interelectrode sealing is used for the convenience of measurement. FIG. 24 is a schematic cross-sectional view of the circuit board according to the embodiment in which the light reflecting portion is disposed. The comparative example also adopts a similar configuration. As a circuit board for evaluation, a board 9g is provided with two wiring portions 9f. The board 9g uses a bismaleimide triazine resin having a thickness of 0.3 mm, the wiring portion 9f uses a copper foil having a thickness of 0.018 mm, and the distance between the two wiring portions 9f is 0.2 mm. The light reflecting portion 20f is disposed so as to contact the two wiring portions 9f. The light reflecting portion 20f is formed into a coating having a thickness of 0.3 mm by using a compression molding method. The molding conditions of the compression molding method are a mold temperature of 120° C. or more and 140° C. or less, and a curing time of about 4 minutes. After the light reflecting portion 20f is primarily cured using a compression molding machine, a post cure (secondary curing) is carried out at 150° C. for about 4 hours in order to complete the resin reaction.

(Evaluation of current-voltage characteristics)
An oscilloscope is used to measure the current value that flows when voltages ranging from 0 V to 400 V are applied between two wires on the evaluation board. Fig. 25 shows the measurement results showing the current-voltage characteristics of the light emitting device according to the example.

In the measurement results, Examples 1 to 5 and Comparative Example 3 exhibited varistor characteristics from the current-voltage characteristics, with Examples 2, 3, and 5 in particular exhibiting high varistor characteristics. On the other hand, Comparative Examples 1 and 2 did not exhibit varistor characteristics. For Examples 1 to 5, the nonlinearity coefficient (α value) was calculated from the varistor current-voltage characteristics. Specifically, the α that fits I=K·Vα was determined from the curve of the graph. The results showed that Example 3 was best, followed by Example 2 and Example 5, with Example 3 being the best.

(Light reflectance)
Next, the light reflectance of the surface of the light reflecting portion according to the embodiment and the comparative example was measured. The light reflectance was measured using a high-speed spectrophotometer (CMS-35SP) manufactured by Murakami Color Research Laboratory. Fig. 26 is a diagram showing the light reflectance of the light emitting device according to the embodiment.

These results show that Examples 1 to 5 exhibit higher light reflectance than Comparative Example 3. Specifically, Examples 1 to 5 had a light reflectance of at least 50% in the wavelength range of 450 nm or more and 800 nm or less.

From these, the light reflecting parts according to Examples 1 to 5 have a light reflectance of at least 50% or more in the wavelength range of 450 nm or more and 800 nm or less, and have varistor characteristics. In particular, Examples 3, 2, and 5 have high varistor characteristics with a nonlinearity coefficient (α value) of 4 or more. The light reflecting parts according to Examples 1 to 5 have a light reflectance of 60% or more for a wavelength of 450 nm, and a light reflectance of 75% or more for a wavelength of 730 nm.

The light-emitting device and light source according to the embodiment of the present disclosure can be used as a backlight source for liquid crystal displays, various lighting fixtures such as in-vehicle or general indoor and outdoor lighting, indoor and outdoor displays, and various display devices such as for advertisements and destination guidance.

LIST OF SYMBOLS 1 First surface 2 Second surface 3 Side surface 5 Element substrate 6 Semiconductor layer 7 Element electrode 7a n-side electrode 7b p-side electrode 7c Coating 8 Package 8a First lead frame wiring portion 8b Second lead frame wiring portion 8c Fixing portion 8d Sealing member 9a First wiring portion 9b Second wiring portion 9c Substrate 9f Wiring portion 9g Substrate 10 Light emitting element 20, 20f Light reflecting portion 21 Semiconductive material 21a First powder 21b Second powder 22 Light reflective material 23 Binder 40 Wavelength conversion member 41 Wavelength conversion member 42 Light transmissive member 43 Light reflective layer 44 Lens 50 Adhesive 70 Circuit substrate A, B Dicing blade

Claims (15)

a light emitting element having a first surface, a second surface opposite to the first surface, and a side surface connected to the first surface and the second surface, the light emitting element having a pair of element electrodes having different polarities on the second surface;
a light reflecting portion including a powdered semiconductive material, a powdered light reflecting material, and an insulating binder;
Equipped with
the semiconductive material has a first powder having at least one shape selected from the group consisting of a sphere, a long spheroid, an ellipsoid, a substantially sphere, a substantially long spheroid, and a substantially ellipsoid, and a second powder having a needle-like shape extending in one direction or in two or more directions;
the light reflecting portion is disposed so as to be in contact with each of the pair of element electrodes,
The light emitting device, wherein the light reflecting portion has a light reflectance of 50% or more in a wavelength range of 450 nm or more and 800 nm or less, and has varistor characteristics. The light-emitting device according to claim 1, wherein the varistor characteristics have a nonlinearity coefficient (α) of 3 or more. The light emitting device according to claim 1 or 2, further comprising a wavelength conversion member facing the first surface of the light emitting element. The light emitting device according to claim 3, wherein the light reflecting portion is disposed on the side or lateral side of the light emitting element and/or on the side or lateral side of the wavelength conversion member. The light-emitting device according to claim 1 or 2, wherein the first powder and the second powder are 30 to 450 parts by weight and 20 to 200 parts by weight, respectively, relative to 100 parts by weight of the binder. The light-emitting device according to claim 1 or 2, wherein the weight ratio of the second powder to the first powder is 4.4% or more and 667% or less. The light-emitting device according to claim 1 or 2, wherein the first powder has a diameter or major axis of 1 μm or more and 50 μm or less, and the second powder has an average fiber length of 1 μm or more and 50 μm or less. 3. The light emitting device according to claim 1, wherein the semiconductive material is at least one selected from the group consisting of _BaTiO3 , _SrTiO3 , ZnO, BiO, CoO, MnO, SbO, CrO, NiO, SiN, and SiO. The first powder is ZnO having a purity of 95% or more,
3. The light emitting device according to claim 1, wherein the first powder does not contain Al, Bi, Sb, Co, Mn, or an oxide or nitride containing at least one selected from these, or the content of the element is 0.01% by weight or less. The light-emitting device according to claim 1 or 2, wherein the second powder has a volume resistivity of 0.1 Ω·cm or more and 1000 Ω·cm or less. The light-emitting device according to claim 1 or 2, wherein the binder is a silicone resin, a silicone-modified resin, an epoxy resin, an epoxy-modified resin, or a hybrid resin containing at least one of these, glass, or ceramics. The light-emitting device according to claim 1 or 2, wherein the light-reflecting material is at least one selected from titanium oxide, barium titanate, aluminum oxide, and silicon oxide. The light-emitting device according to claim 1 or 2, wherein the light reflecting portion further contains either fumed silica or higher fatty acid amide. a light emitting element having a first surface, a second surface opposite to the first surface, and a side surface connected to the first surface and the second surface, the light emitting element having a pair of element electrodes having different polarities on the second surface;
a first lead frame wiring portion electrically connected to the pair of element electrodes, and a second lead frame wiring portion spaced apart from the first lead frame wiring portion;
a light reflecting portion including a powdered semiconductive material, a powdered light reflecting material, and an insulating binder;
Equipped with
the semiconductive material has a first powder having at least one shape selected from the group consisting of a sphere, a long spheroid, an ellipsoid, a substantially sphere, a substantially long spheroid, and a substantially ellipsoid, and a second powder having a needle-like shape extending in one direction or in two or more directions;
the light reflecting portion is disposed so as to be in contact with each of the first lead frame wiring portion and the second lead frame wiring portion;
The light emitting device, wherein the light reflecting portion has a light reflectance of 50% or more in a wavelength range of 450 nm or more and 800 nm or less, and has varistor characteristics. a light emitting element having a first surface, a second surface opposite to the first surface, and a side surface connected to the first surface and the second surface, the light emitting element having a pair of element electrodes having different polarities on the second surface;
a circuit board including at least two wiring portions electrically connected to the pair of element electrodes;
a light reflecting portion including a powdered semiconductive material, a powdered light reflecting material, and an insulating binder;
Equipped with
the semiconductive material has a first powder having at least one shape selected from the group consisting of a sphere, a long spheroid, an ellipsoid, a substantially sphere, a substantially long spheroid, and a substantially ellipsoid, and a second powder having a needle-like shape extending in one direction or in two or more directions;
the light reflecting portion is disposed so as to be in contact with each of the two wiring portions,
The light source, wherein the light reflecting portion has a light reflectance of 50% or more in a wavelength range of 450 nm or more and 800 nm or less, and has varistor characteristics.

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