JP7137050B2 - Light-emitting device and manufacturing method thereof - Google Patents

Description

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

Conventionally, resin materials such as epoxy resins and silicone resins have been used as sealing members for protecting light emitting elements mounted in light emitting devices. 2. Description of the Related Art In recent years, silicone-based resin materials with excellent heat resistance are mainly used for sealing members for protecting high-output and high-brightness light-emitting elements mounted in lighting fixtures, backlights of liquid crystal panels, and the like.

By the way, the silicone-based resin material has excellent heat resistance, but also has adhesiveness (tackiness). For example, in Patent Literature 1, fine particles such as SiO ₂ are adhered to the surface of the resin after the silicone resin is cured, thereby suppressing stagnation of work due to sticking of the light emitting device to a tool or the like.

JP 2009-141051 A

However, if fine particles such as SiO ₂ are attached to the surface of the silicone resin, the fine particles may fall off due to impact or the like.

An object of the embodiments of the present disclosure is to provide a light-emitting device in which the tackiness of a sealing member is reduced, and a method for manufacturing the light-emitting device.

A light-emitting device according to an embodiment of the present disclosure includes a light-emitting element, a translucent member covering the light-emitting element, and a light diffusing agent contained in the translucent member, wherein the light diffusing agent is It is hollow and has a particle size of 50 μm or more, and the surface of the translucent member has irregularities caused by the light diffusing agent.

A method for manufacturing a light-emitting device according to an embodiment of the present disclosure includes steps of mounting a light-emitting element in a concave portion of a substrate; a step of floating the light diffusing agent up to the surface of the injected silicone resin; and a step of curing the silicone resin.

According to the method for manufacturing a light emitting device according to the embodiment of the present disclosure, it is possible to reduce the tackiness of the sealing member.

It is a top view which shows typically the light-emitting device which concerns on this embodiment. FIG. 1B is a cross-sectional view of the light emitting device according to the present embodiment taken along line IB-IB in FIG. 1A. FIG. 1C is an enlarged view showing the surface of the translucent member in FIG. 1B of the light emitting device according to the present embodiment; 4 is a flow chart showing the procedure of the method for manufacturing the light emitting device according to this embodiment. FIG. 4 is a cross-sectional view showing a light-emitting element mounting step in the method for manufacturing the light-emitting device according to this embodiment; FIG. 4 is a cross-sectional view showing a resin filling step in the method for manufacturing the light emitting device according to this embodiment; FIG. 4 is a cross-sectional view showing a resin filling step in the method for manufacturing the light emitting device according to this embodiment; FIG. 4 is a cross-sectional view showing a light diffusing agent floating step in the method for manufacturing the light emitting device according to this embodiment. FIG. 4 is a cross-sectional view showing a resin curing step in the method for manufacturing the light emitting device according to this embodiment; FIG. 4 is a plan view schematically showing another light emitting device according to this embodiment; 4B is a cross-sectional view of the light-emitting device taken along IVB-IVB in FIG. 4A; FIG. [FIG. 2] is a cross-sectional view schematically showing a state in which a phosphor and a light diffusing agent are contained in a translucent member in another method for manufacturing a light-emitting device according to the present embodiment; FIG. 11 is a cross-sectional view schematically showing a state in which the phosphor is sedimented and the light diffusing agent is raised in another method for manufacturing a light-emitting device according to the present embodiment; FIG. 4 is a diagram showing the results of a sticking test and a rolling ball tack test; FIG. 4 is a photograph showing a light-emitting device manufactured under the conditions of Examples 1 and 2 and Comparative Examples 1 and 2, which are examples and comparative examples of the light-emitting device according to the present disclosure.

A light-emitting device and a method for manufacturing the same according to embodiments will be described below. It should be noted that the drawings referred to in the following description are schematic representations of the embodiments, and therefore the scales, intervals, positional relationships, etc. of each member are exaggerated, or illustration of some of the members is omitted. Sometimes. In addition, for example, the plan view and the cross-sectional view thereof may not match the scale and spacing of each member. In addition, in the following description, the same names and symbols basically indicate the same or homogeneous members, and detailed description thereof will be omitted as appropriate. Tackiness means stickiness.

≪Light emitting device≫
First, the configuration of a light emitting device 100 according to this embodiment will be described with reference to FIGS. 1A, 1B, and 1C. 1A is a plan view schematically showing a light emitting device 100 according to the present embodiment, FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A, and FIG. It is an enlarged view which shows the surface of a member. In addition, FIG. 1A describes the same hatching corresponding to the hatching given to each member in the cross-sectional view of FIG. 1B.

The light-emitting device 100 includes a light-emitting element 1 provided on a substrate 2 , a translucent member 3 covering the light-emitting element 1 , and a light diffusion agent 4 contained in the translucent member 3 . A light emitting element 1 is mounted on a substrate 2 . The light diffusing agent 4 is hollow and has a particle size of 50 μm or more, and the surface of the translucent member 3 has unevenness caused by the light diffusing agent 4 .

The light emitting element 1 is mounted on the substrate 2 by wire bonding using gold wires, flip chip bonding using solder or silver paste, or the like. The number of light emitting elements 1 mounted on the substrate 2 may be one or plural. A known element can be used as the light emitting element 1, and for example, it is preferable to use a light emitting diode or a laser diode. Moreover, the light emitting element 1 is electrically connected to the wiring 5 exposed on the bottom surface 23b of the concave portion 23a of the substrate 2, and emits light in a wavelength range from ultraviolet light to red light. For example, as the blue and green light emitting elements 1, nitride semiconductors InxAlyGa1 _- XYN, _0≤X , 0≤Y, _X +Y≤1, GaP, etc. can be used. Further, for example, as the red light emitting element 1, GaAlAs, AlInGaP, etc. can be used in addition to the nitride semiconductor element. The light emitting element 1 may have a polygonal shape such as a square, rectangle, triangle, hexagon, or the like, or may have a circular shape, an elliptical shape, or the like in plan view.

At least one or more light emitting elements 1 are mounted on the substrate 2, and the light emitting device 100 is electrically connected to the outside. The substrate 2 includes a flat support member and wiring 5 arranged on the surface and/or inside the support member. The substrate 2 has a concave portion 23a, and in plan view, the external shape and the internal shape inside the concave portion 23a are substantially square. The inner side surface of the concave portion 23a is formed into an inclined surface that is slanted so as to widen upward. This inner surface is the light emitting element 1
The light from above is reflected by the slanted surface and efficiently guided upward, which is the light extraction direction. In addition, the substrate 2 may have a heat dissipation terminal electrically independent from the light emitting element 1 on the lower surface. It is preferable that the heat dissipation terminal is formed so as to have an area larger than the sum of the top surface areas of all the light emitting elements 1 included in the light emitting device 100, and is arranged so as to overlap the area immediately below the light emitting element 1. . With such a configuration of the heat dissipation terminals, the light emitting device 100 can be made more excellent in heat dissipation.

The supporting member of the substrate 2 is preferably made of an insulating material, and preferably made of a material that does not easily transmit the light emitted from the light emitting element 1, external light, and the like. A material having a predetermined strength is preferably used for the supporting member of the substrate 2 . Specifically, alumina, aluminum nitride, ceramics such as mullite, phenol resin, epoxy resin, polyimide resin, bismaleimide triazine resin (BT resin), polyphthalamide (PPA), polyamide (PA), unsaturated polyester, etc. resin.

The wiring 5 is a pair of wirings 5a and 5b corresponding to positive and negative polarities. The wiring 5 is supported by the support member of the substrate 2, and is arranged so that the upper surface of the wiring 5a and the upper surface of the wiring 5b are separated from each other and exposed to the bottom surface 23b of the recess 23a. The wiring 5 is formed using, for example, a plate-shaped metal, and the thickness thereof may be uniform, or may be partially thicker or thinner. The wiring 5 is preferably made of a material with high thermal conductivity, a material with high mechanical strength, or a material that can be easily punched, pressed, or etched. Examples of such materials include metals such as copper, aluminum, gold, silver, tungsten, iron and nickel, and alloys such as iron-nickel alloys and phosphor bronze. The wiring 5 can be formed by electrolytic plating, electroless plating, vapor deposition, sputtering, or the like.

The translucent member 3 is provided in the recess 23 a to cover the light emitting element 1 . The translucent member 3 contains a light diffusing agent 4 , and the surface of the translucent member 3 has unevenness caused by the light diffusing agent 4 . The contact area when the surface of the translucent member 3 has unevenness is smaller than the contact area when the surface of the translucent member 3 does not have unevenness, that is, when the surface is flat. Therefore, the translucent member 3 has unevenness on the surface, thereby reducing the tackiness of the surface. The unevenness is preferably formed on the entire surface area of the translucent member 3 , but may be formed on a partial area of the surface of the translucent member 3 . As described above, the translucent member 3 preferably has a predetermined degree of unevenness on its surface. As for the surface condition of the translucent member 3, the addition of the light diffusing agent 4 makes the surface rougher and more likely to form irregularities. As for the irregularities on the surface of the translucent member 3, the surface roughness of the translucent member 3 is preferably 0.3 μm or more and 0.6 μm or less. By setting it within this range, the tackiness can be reduced and the total luminous flux can be increased. The surface of the translucent member 3 is a surface facing the bottom surface 23b of the recess 23a, and basically refers to the upper surface of the translucent member 3. may contain a part of

As shown in FIG. 1C, the surface of the translucent member 3 includes an exposed portion A where the light diffusing agent 4 is exposed from the translucent member 3 and a covered portion B where the translucent member 3 covers the light diffusing agent 4. and The light-transmitting member 3 does not necessarily need to cover the entire light-diffusing agent 4, and the light-diffusing agent 4 is applied near the surface of the light-transmitting member 3 so that the surface of the light-transmitting member 3 has unevenness. It is good if it is arranged. Since the translucent member 3 is softer than the light diffusing agent 4, the translucent member 3 is resistant to impact, and the light diffusing agent 4 is less likely to break even at the exposed portion A. Further, at least part of the light diffusing agent 4 is embedded in the translucent member 3 in both the exposed portion A and the covered portion B. As shown in FIG. Therefore, the light-emitting device 100 according to the embodiment is less likely to fall off or break due to impact or the like, compared to a conventional light-emitting device in which fine particles are attached to the surface of a cured silicone resin afterward.

The translucent member 3 is preferably made of a material having good translucency, such as a thermosetting resin, a thermoplastic resin, or the like. Examples of thermosetting resins include silicone resins, silicone-modified resins, silicone hybrid resins, epoxy resins, epoxy-modified resins, urea resins, diallyl phthalate resins, phenol resins, unsaturated polyester resins, or one or more of these resins. hybrid resins, and the like. In particular, silicone resins or their modified resins or hybrid resins are preferable because they are excellent in heat resistance and light resistance. Translucent member 3 may have a transmittance of 50% or more, preferably 70% or more, and more preferably 85% or more.

The light diffusing agent 4 is hollow microparticles. In FIG. 1A, the light diffusing agents 4 are shown to be arranged evenly on the surface of the translucent member 3, but in reality, they are arranged on the surface of the translucent member 3 at random with respect to their mutual distance and exposure state. It is The light diffusing agent 4 is partially covered with the translucent member 3 and partially exposed from the translucent member 3 . The particle diameter of the light diffusing agent 4 is preferably 50 μm or more, and more preferably 65 μm or more and 70 μm or less. If the particle diameter of the light diffusing agent 4 is small, it is difficult to float in the translucent member 3 and the tackiness of the translucent member 3 tends to increase. Also, the larger the particle diameter of the light diffusing agent 4 and the smaller the hollow volume, the easier it is to settle in the translucent member 3 . Therefore, by setting the particle size within this range, the light diffusing agent 4 can be easily floated up to the surface of the translucent member 3 . As a result, suitable irregularities can be formed on the surface of the translucent member 3, so that the tackiness of the surface of the translucent member 3 can be reduced. Furthermore, by reducing the tackiness of the translucent member 3, it is possible to suppress work stagnation due to, for example, the light emitting device sticking to a tool or the like, or a plurality of light emitting devices sticking together during transportation.

The light diffusing agent 4 preferably has a bulk density (or specific gravity) of 0.1 g/cm ³ or more and 0.7 g/cm ³ or less with respect to the translucent member 3 , and a bulk density of 0.1 g/cm 3 or more and 0.7 g/cm 3 or less with respect to the translucent member 3 . It is more preferably 1 g/cm ³ or more and 0.2 g/cm ³ or less. The smaller the bulk density of the light diffusing agent 4 with respect to the translucent member 3, the easier it is to float. On the other hand, if the bulk density of the light diffusing agent 4 is too low, problems such as the light diffusing agent 4 floating during dispersion to the translucent member 3 or being unevenly distributed within the dispenser will occur, resulting in poor workability. By setting the bulk density within this range, the light diffusing agent 4 can be floated to the surface of the translucent member 3 after being dispersed in the translucent member 3. Therefore, unevenness is easily formed on the surface of the translucent member 3 .

The light diffusing agent 4 preferably has a spherical shape. Since the light diffusing agent 4 is spherical, a plurality of uniform irregularities are easily formed on the surface of the translucent member 3 . The light diffusing agent 4 may be white hollow fine particles, or may be transparent hollow fine particles that appear white due to scattering due to the difference in refractive index from surrounding materials. The light diffusing agent 4 can scatter the light emitted by the light emitting element 1 and improve the light extraction efficiency of the light emitting device 100 . Therefore, it is preferable that the light diffusing agent 4 is made of a material having a large difference in refractive index from that of the translucent member 3 . Examples of the material of the light diffusing agent 4 include fine powder (hollow filler) containing hollow silica, hollow glass, hollow ceramic, fly ash, Shirasu balloon, hollow polymer, porous silica, porous polymer, and the like. be done. The light diffusing agent 4 may be a fine powder (hollow filler) in which a plurality of these materials are mixed. For example, by using silicone resin with a refractive index of 1.50 to 1.55 for the translucent member 3 and using hollow silica with a refractive index of 1.35 to 1.45 for the light diffusing agent 4, the light emitting element 1 It is possible to increase the efficiency of extracting light from, etc. to the outside.

The amount of the light diffusing agent 4 added to the translucent member 3 is preferably 0.2 parts or more and 3 parts or less, and the amount added to the translucent member 3 is 0.2 parts or more and 1.5 parts or less. is more preferable. The greater the amount of the light diffusing agent 4 added, the more the tackiness of the translucent member 3 can be reduced. Further, when the amount of the light diffusing agent 4 added is too large, the luminous intensity of the light-emitting device decreases due to a decrease in transmittance, and workability deteriorates due to an increase in the tackiness of the translucent member 3 . By setting the amount of the light diffusing agent 4 added to the light-transmitting member 3 within the above range, moderate unevenness is formed on the surface of the light-transmitting member 3 without causing a reduction in the luminous intensity of the light-emitting device. 3 can be reduced. The unit of the amount of the light diffusing agent 4 added, "part", corresponds to the weight of the light diffusing agent 4 with respect to 100 g of the translucent member. For example, the amount of the light diffusing agent 4 added of 50 parts means that the amount of the light diffusing agent 4 added is 50 g with respect to 100 g of the translucent member.

According to the light emitting device 100 according to the present embodiment, the light diffusing agent 4 originally added to the translucent member 3 for controlling light distribution is used, and the particle size, bulk density, and By appropriately adjusting the addition amount, etc., the surface of the light-transmitting member 3 is made uneven. Thereby, the light-emitting device 100 in which the tackiness of the translucent member 3 is reduced can be realized. In addition, the unevenness formed on the surface of the translucent member 3 effectively scatters external light, and the light-emitting device 100 having a uniform color on the light-emitting surface can be realized.

<<Method for manufacturing light-emitting device>>
Next, a method for manufacturing the light emitting device according to this embodiment will be described with reference to FIGS. 2 and 3A to 3E. Note that the order of some steps is not limited, and the order may be changed.

FIG. 2 is a flow chart showing the procedure of the method for manufacturing the light emitting device according to this embodiment. The manufacturing method of the light emitting device according to this embodiment includes a light emitting element mounting step S21, a resin filling step S22, a light diffusing agent floating step S23, and a resin curing step S24.

FIG. 3A is a cross-sectional view showing a light-emitting element mounting step in the method for manufacturing a light-emitting device according to this embodiment. 3B and 3C are cross-sectional views showing the resin filling step in the method for manufacturing the light emitting device according to this embodiment. FIG. 3D is a cross-sectional view showing a light diffusing agent floating step in the method for manufacturing the light emitting device according to this embodiment. FIG. 3E is a cross-sectional view showing a resin curing step in the method for manufacturing the light emitting device according to this embodiment.

As shown in FIG. 3A, the light emitting element mounting step S21 is a step of mounting the light emitting element 1 in the concave portion 23a of the substrate 2. As shown in FIG. In the light emitting element mounting step S21, the light emitting element 1 is mounted on the substrate 2 and electrically connected to the wiring 5 by wires or bumps.

As shown in FIG. 3B, the resin filling step S22 is a step of injecting and filling the concave portion 23a of the substrate 2 with a silicone resin that will become the translucent member 3. As shown in FIG. In the resin filling step S22, the light diffusing agent 4 is added to the silicone resin in advance, and the light diffusing agent 4 is uniformly dispersed in the silicone resin. The silicone resin is dripped into the concave portion 23a of the substrate 2 by, for example, a potting method using a dispenser.

As shown in FIG. 3C, in the resin filling step S22, the silicone resin to which the light diffusing agent 4 is added is filled up to the uppermost surface of the concave portion 23a. By using the light diffusing agent 4 having a predetermined particle size, bulk density, and addition amount, the light diffusing agent 4 is uniformly dispersed in the silicone resin while preventing an increase in the tackiness of the silicone resin in the next step S23. After that, it becomes possible to float the light diffusing agent 4 up to the vicinity of the surface of the silicone resin.

As shown in FIG. 3D, the light diffusing agent floating step S23 is a step of floating the light diffusing agent 4 to the surface of the silicone resin. In the light diffusing agent floating step S23, the silicone resin in which the light diffusing agent 4 is uniformly dispersed is left at 40° C. for 12 hours. Since the light diffusing agent 4 is lighter than the silicone resin, and the particle size and the like are adjusted as described above, it gradually floats in the uncured silicone resin over time (Fig. 3D arrow), and eventually floats near the surface of the silicone resin. As a result, unevenness due to the shape of the light diffusing agent 4 is formed on the surface of the silicone resin.

As shown in FIG. 3E, the resin curing step S24 is a step of curing the silicone resin. In the resin curing step S24, the silicone resin is heated at 150° C. for 4 hours. When the silicone resin is cured by heating, the light diffusing agent 4 floated to near the surface of the silicone resin is fixed near the surface of the silicone resin, and irregularities are formed on the surface of the silicone resin. The heating temperature is preferably adjusted to around 150° C. in order to form unevenness on the surface of the silicone resin to reduce tackiness.

As described above, the light-emitting device 100 is manufactured by performing the above-described steps. Although one light-emitting device 100 has been described in each of the above steps, actually, a plurality of light-emitting devices 100 are formed at once with the substrate 2 being continuous, and then separated into individual pieces. The light emitting device 100 is separated.

According to the method for manufacturing a light-emitting device according to the present embodiment, the particle size, bulk density, addition amount, and the like are appropriately adjusted to float the light diffusing agent 4 to the vicinity of the surface of the silicone resin. Then, irregularities caused by the light diffusing agent 4 are formed. As a result, a method for manufacturing a light-emitting device in which the tackiness of the silicone resin is reduced can be achieved. Moreover, since at least part of the light diffusing agent 4 is embedded in the silicone resin, it is possible to provide a method for manufacturing a light-emitting device in which the light diffusing agent 4 does not come off due to impact or the like.

Further, according to the method for manufacturing a light-emitting device according to the present embodiment, the surface of the cured resin is hard-coated with a low-viscoelastic material, sprayed with a release coating agent, or the like, thereby improving the tackiness. can be simplified and the number of steps can be reduced compared to the conventional method of reducing the Furthermore, according to the method for manufacturing a light emitting device according to the present embodiment, irregularities are formed on the surface of the resin while integrating the silicone resin and the light diffusing agent. Therefore, it is possible to reduce the tackiness of the silicone resin by minimizing the occurrence of problems such as a decrease in the light extraction efficiency due to the interface formed between the coating layer and the resin layer as in the conventional art. can.

Furthermore, in the light emitting device, the translucent member 3 may contain the phosphor 6 together with the light diffusing agent 4 . The light emitting device 100A will be described below with reference to FIGS. 4A and 4B. It should be noted that the same reference numerals are assigned to the configurations already described, and the description thereof will be omitted as appropriate. FIG. 4A is a plan view schematically showing another light emitting device according to this embodiment. Also, FIG. 4B is a cross-sectional view of the light-emitting device along IVB-IVB in FIG. 4A.
The light-emitting device 100A includes a light-emitting element 1 provided on a substrate 2, a translucent member 3A covering the light-emitting element 1, a light diffusing agent 4 and a phosphor (wavelength conversion substance) 6 contained in the translucent member 3A. It has In the light emitting device 100A, the alignment state of the light diffusing agents 4 in the translucent member 3A is such that the light diffusing agents 4 in the adjacent row are positioned between the light diffusing agents 4 in the next row to fill the space without gaps. 4A), the light diffusing agents 4 may be adjacent to each other as described above (see FIG. 1A), or both may be mixed.

(Phosphor)
The phosphor 6 may absorb light from the light emitting element 1 and convert the wavelength into light of a different wavelength. For example, cerium-activated yttrium aluminum garnet (YAG:Ce) phosphors, cerium-activated lutetium aluminum garnet (LAG:Ce), nitrogen-containing aluminosilicates activated with europium and/or chromium Calcium (CaO--Al ₂ O ₃ --SiO ₂ :Eu,Cr) phosphor, europium-activated silicate ((Sr,Ba)2SiO ₄ :Eu) phosphor, β-sialon phosphor, CaAlSiN ₃ :Eu Nitride phosphors such as (CASN) and (Sr, Ca)AlSiN ₃ :Eu(SCASN) phosphors, K ₂ SiF ₆ :Mn(KSF) phosphors, sulfide phosphors, etc. . As a result, a light emitting device that emits a mixed color light (for example, white light) of primary light and secondary light of visible wavelengths, or a light emitting device that emits secondary light of visible wavelengths by being excited by primary light of ultraviolet light. can do. Phosphor 6 may be used by combining a plurality of types of phosphors. Color rendering properties and color reproducibility can also be adjusted by using combinations and mixing ratios suitable for a desired color tone. The particle number density of the phosphor 6 on the light emitting element 1 side in the translucent member 3A should be higher than the particle number density of the phosphor 6 on the surface side of the translucent member 3A in the translucent member 3A. is preferred. By increasing the particle number density of the phosphor 6 on the light emitting element 1 side, the wavelength conversion rate can be increased, and the amount of the phosphor 6 to be added to achieve the desired chromaticity can be reduced. .

Regarding the specific gravity of the phosphor 6, the difference in specific gravity with respect to the translucent member 3A is preferably 0.5 g/cm ³ or more and 10 g/cm ³ or less, and further, the specific gravity difference with respect to the translucent member 3A is 1 g/cm ³ or more. It is more preferably 6 g/cm ³ or less. After the fluorescent substance 6 is dispersed in the translucent member 3A, the concave portion 23a of the substrate 2 is filled with the fluorescent substance 6, thereby causing the fluorescent substance 6 to settle. At this time, by adjusting the specific gravity of the phosphor 6 to the range, the dispersibility is improved and the sedimentation is also performed quickly. The density can be increased and the wavelength conversion rate can be increased.

The relationship between the sedimentation of the phosphor 6 and the floating of the light diffusing agent (hollow filler) 4 will be described with reference to FIGS. 5A and 5B. FIG. 5A is a cross-sectional view schematically showing a state in which a phosphor and a light diffusing agent are contained in a translucent member in another method for manufacturing a light-emitting device according to this embodiment. Moreover, FIG. 5B is a cross-sectional view schematically showing a state in which the phosphor has settled and the light diffusing agent has risen in another method for manufacturing a light-emitting device according to this embodiment.
The phosphor 6 and the light diffusing agent 4 are contained in a silicone resin and filled in the concave portion 23a. Furthermore, by waiting for a predetermined time, the light diffusing agent 4 floats due to the difference in specific gravity between the silicone resin that is the translucent member 3A and the light diffusing agent 4, and the difference in specific gravity between the translucent member 3A and the phosphor 6. As a result, the phosphor 6 settles. The particle number density of the light diffusing agent 4 on the surface of the light emitting surface is higher than that of the phosphor 6 . Also, the particle number density of the phosphor 6 on the light emitting element 1 side is higher than that of the light diffusing agent 4 . 3B to 3E in the method of manufacturing the light-emitting device already described, and the filled silicone resin (translucent member 3A) contains the light diffusing agent 4 and the phosphor 6. becomes. Other steps are the same in the method of manufacturing the light emitting device.

Furthermore, the specific gravity of the translucent member 3A is 1.1 to 1.5 g/cm ³ . Regarding the relationship between the translucent member 3A and the phosphor 6, the specific gravity difference with respect to the phosphor 6 is preferably 0.5 g/cm ³ or more and 10 g/cm ³ or less, and the specific gravity difference with respect to the phosphor 6 is preferably 1 g/cm ³ or more and 6 g. /cm ³ or less. The light diffusing agent 4 preferably has a bulk density (or specific gravity) of 0.1 g/cm ³ or more and 0.7 g/cm ³ or less with respect to the translucent member 3A. It is more preferably 0.1 g/cm ³ or more and 0.2 g/cm ³ or less. The particle number density of the light diffusing agent 4 on the surface of the translucent member 3A is higher than the particle number density of the phosphor 6.

Examples of light emitting devices according to the present disclosure are described below. Note that the light emitting device according to the present disclosure is not limited to the following examples.
<<Examples 1 and 2, and Comparative Examples 1 and 2>>
A light-emitting device 100 was manufactured by the method for manufacturing a light-emitting device according to the present embodiment. A light-emitting device in which the amount of the light diffusing agent added to the translucent member was 0.2 parts was defined as Example 1. A light-emitting device in which the amount of the light diffusing agent added to the translucent member was 1.5 parts was taken as Example 2.
Details of each component in Examples 1 and 2 are shown below.

Light emitting element 1
Quantity: 1 mounted Type: Blue light with a peak emission wavelength of 455 nm is emitted External dimensions in plan view: Square with 0.65 mm sides (vertical x horizontal) Height: 200 μm

substrate 2
Material: Epoxy resin Model number: LUEL-300ME
External dimensions in plan view: Square with 3.0 mm sides (vertical x horizontal) Internal dimensions in planar view: Square with 2.6 mm sides (vertical x horizontal) Height: 0.7 mm
Shape: Rectangular parallelepiped

Translucent member 3
Material: Methyl silicone resin (trade name OE-6351 “Dow Corning Toray Co., Ltd.”)
Dimensions in plan view: Square with 2.6 mm sides (length x width) Thickness: 41 μm
Curing conditions: 40°C x 12hr + 150°C x 4hr

Light diffusing agent 4
Type: Hollow filler Average particle size: 65 μm
Specific gravity: 0.13
Shape: Spherical

A light-emitting device according to a comparative example was manufactured for comparison with the light-emitting device according to the example. Comparative Example 1 was a light-emitting device in which the amount of the light diffusing agent added to the translucent member was 0.1 part. Comparative Example 2 is a light-emitting device in which a light-diffusing agent is not added to the translucent member. It was formed in the same manner as in Example 1 except for the amount of the light diffusing agent added to the translucent member. The details of each component in Comparative Examples 1 and 2 are as described above. Since the light-emitting device in which the light-diffusing agent is not added to the translucent member is referred to as Comparative Example 2, the particle size [μm] column corresponding to Comparative Example 2 is blank in Table 1 described later. ing.

The following experiments were performed on the light emitting devices according to Examples 1 and 2 and the light emitting devices according to Comparative Examples 1 and 2.

Sticking Test A plurality of the light-emitting devices of Examples 1 and 2 and Comparative Examples 1 and 2 are placed in IC packs, respectively, and the IC packs are placed in a cylindrical container for rotating on a ball mill to remove static electricity. Furthermore, the light-emitting devices of Examples 1 and 2 and Comparative Examples 1 and 2, which were static electricity removed and kept in the IC pack, were rotated in a ball mill together with the cylindrical container, and then the IC pack was taken out from the container. Further, each light emitting device is taken out from the IC pack, and the number of sticking light emitting devices is measured.
Static elimination: 2 minutes Ball mill: 5 minutes

Measurement of Radiant Flux For Examples 1 and 2 and Comparative Examples 1 and 2, a spectroscope was used to measure the radiant flux.

Rolling Ball Tack Test A ball was rolled on a resin plate (inclined plate), and the distance (stopping distance) from the position where the ball started to roll to the position where the ball stopped was measured. The greater the tackiness of the resin plate, the shorter the stopping distance, and the less the tackiness of the resin plate, the longer the stopping distance. Therefore, the tackiness of the resin plate was evaluated by measuring the stopping distance. The resin plate was formed of the same material as the translucent member provided in Examples 1 and 2 and Comparative Examples 1 and 2, respectively.
Ball: Polyamide 66 (PA66)
Inclined plate angle: 5°
Run-up distance: 2cm
Resin plate size: 140mm x 70mm x 3tmm

Table 1 shows the evaluation results.
Table 1 shows the addition amount [phr (parts)], particle size [μm], specific gravity [g/cm ³ ], sticking occurrence rate [%], radiation It is a table summarizing bundles [W]. The sticking occurrence rate is a value obtained by dividing the number of sticking light emitting devices taken out from an IC pack by the total number of light emitting devices and multiplying by 100. FIG. The number of sticking means the number of light emitting devices sticking to each other immediately after being rotated by the ball mill, and also includes the number of light emitting devices separated with the lapse of time. A radiant flux is a value of radiant energy passing through a predetermined plane within a unit time.

From this result, the sticking occurrence rate was 80% or less in Examples 1 and 2, but was 90% or more in Comparative Examples 1 and 2. In particular, the sticking occurrence rate was 0% in Example 2. Moreover, the radiant flux was not significantly different between Examples 1 and 2 and Comparative Examples 1 and 2, but the radiant flux in Example 1 was larger than the radiant flux in Comparative Example 2.

Therefore, by adding 0.2 parts or more of a light diffusing agent having a particle size of 50 μm or more to the silicone resin, the tackiness of the light-emitting device can be reduced. Further, by adding 1.5 parts of the light diffusing agent to the silicone resin, the tackiness in the light emitting device can be completely eliminated. Moreover, the bulk density of the light diffusing agent with respect to the silicone resin is preferably in the range of 0.1 g/cm ³ or more and 0.2 g/cm ³ or less. The unevenness of the surface of the translucent member 3 was Ra=0.37 μm as the surface roughness when using the light diffusing agent 4 having a size that was effective in reducing the tackiness. Therefore, considering the buoyancy of the light diffusing agent 4 and effective tackiness, the surface roughness is preferably 0.3 μm or more and 0.6 μm or less.

Furthermore, the light emitting device in which 0.2 part of the light diffusing agent is added to the silicone resin can improve the light extraction efficiency as compared with the light emitting device in which the light diffusing agent is not added to the silicone resin. Further, even if the light diffusing agent is added to the silicone resin up to 1.5 parts, the light extraction efficiency of the light emitting device can be generally maintained. Moreover, the amount of the light diffusing agent added to the silicone resin is preferably in the range of 0.2 parts or more and 1.5 parts or less.

FIG. 6 is a graph showing measurement results of sticking occurrence rate [%] and stopping distance [cm] in Examples 1 and 2 and Comparative Examples 1 and 2. FIG. The vertical axis on the right side in FIG. 6 indicates the sticking occurrence rate [%], and the vertical axis on the left side indicates the stopping distance [cm].

In FIG. 6, the line with acceptable transportability indicates a line in which the tackiness of the silicone resin is sufficiently reduced so that the stagnation of the work does not occur due to the tackiness of the silicone resin when the light-emitting device sample is transported. ing. That is, if the sticking occurrence rate [%] is smaller than the line value (89%), the transportability is good, and if the stopping distance [cm] is larger than the line value (12 cm), the transportability is good.

From the results, the stopping distance was 14 cm or more in Examples 1 and 2, but 8.8 cm in Comparative Example 1 and 3.8 cm in Comparative Example 2. That is, Examples 1 and 2 were larger than the value of the OK line for transportability, while Comparative Examples 1 and 2 were smaller than the value of the OK line for transportability. The sticking occurrence rate was 80% in Example 1, 0% in Example 2, 90% in Comparative Example 1, and 98% in Comparative Example 2. In other words, Examples 1 and 2 were smaller than the value of the OK line for transportability, while Comparative Examples 1 and 2 were larger than the value of the OK line for transportability.

Therefore, by adding 0.2 part or more of the light diffusing agent having a particle size of 50 μm or more to the silicone resin, the tackiness of the light-emitting device can be reduced, and the stagnation of the work due to the tackiness of the silicone resin does not occur. Moreover, the tackiness in the light-emitting device can be reduced as the amount of the light diffusing agent added increases. Moreover, the particle size of the light diffusing agent is preferably in the range of 65 μm or more and 70 μm or less.
FIG. 7 shows photographs of the light-emitting devices formed in the states of Comparative Examples 1 and 2 and Examples 1 and 2 shown in Table 1, as viewed from above. As shown in FIG. 7, in Examples 1 and 2 of the light-emitting device according to the present disclosure, since unevenness is formed over a wide range on the surface, tackiness is low, and workability is excellent. Observing the state of the surface of Comparative Examples 1 and 2, it was found that unevenness was formed only on a part of the surface, so that the low tackiness of the present example could not be exhibited.

<<Example 3 and Comparative Example 3>>
A light-emitting device 100 was manufactured by the method for manufacturing a light-emitting device according to the present embodiment. In the light-emitting device according to Example 3, the amount of the light-diffusing agent added to the light-transmitting member was 3 parts, and further, the light-emitting color was 5000K and the chromaticity coordinates were (0.347, 0.371). A phosphor was added. Example 3 was formed in the same manner as Example 1 except for the addition amount of the light diffusing agent and the addition of the phosphor to the translucent member.

In the light-emitting device according to Comparative Example 3, a light-diffusing agent was not added to the translucent member, and a phosphor was added so as to obtain an emission color of 5000K and chromaticity coordinates: (0.347, 0.371). Comparative Example 3 was formed in the same manner as in Example 1 except that a phosphor was added to the translucent member.

The following experiments were conducted on the light emitting device according to Example 3 and the light emitting device according to Comparative Example 3.

For Example 3 and Comparative Example 3, the object color was measured using a high-speed colorimetric spectrophotometer (trade name “CMS-35PS”, manufactured by Murakami Color Research Laboratory).

The chromaticity coordinates of the object color were (0.356, 0.361) in Example 3 and (0.456, 0.489) in Comparative Example 3. That is, in Comparative Example 3, the emission color was white, whereas the object color was yellow. This is because the color of the phosphor is visible. On the other hand, in Example 3, both the emission color and the object color were white.

Therefore, a light-emitting device in which a light-diffusing agent is added to the light-transmitting member and a light-emitting device in which the light-diffusing agent is not added to the light-transmitting member have the same emission color, but have different appearance colors. That is, external light can be scattered by unevenness caused by the light diffusing agent having a particle size of 50 μm or more formed on the surface of the translucent member.

In the light-emitting device in which the light-transmitting member was not added with the light-diffusing agent, the portion where the phosphor was present looked dark and conspicuous. 2, the color of the light-emitting surface was whitened, and the portion where the phosphor was present was inconspicuous. That is, the unevenness formed on the surface of the light-transmitting member whitens the appearance of the light-emitting device and makes the color of the light-emitting surface uniform.

Although the embodiments for carrying out the invention have been specifically described above, the gist of the invention is not limited to these descriptions, and should be broadly interpreted based on the description of the scope of claims. In addition, it goes without saying that various changes and modifications based on these descriptions are also included in the gist of the present invention. The light diffusing agent 4 described in each embodiment and the like is used equivalently to hollow filler, fine powder, or fine particles.

A light-emitting device according to an embodiment of the present disclosure can be used for lighting, a backlight for a liquid crystal panel, and the like.

REFERENCE SIGNS LIST 1 light emitting element 2 substrate 3, 3A translucent member 4 light diffusing agent 5 wiring 6 phosphor 23a recessed portion 23b bottom surface 100, 100A light emitting device A exposed portion B covered portion

Claims (12)

a light emitting element;
a translucent member covering the light emitting element;
and a light diffusing agent contained in the translucent member,
The translucent member is either a silicone resin, a silicone-modified resin, or a silicone hybrid resin,
The light diffusing agent is hollow and has a particle size of 50 μm or more,
The light diffusing agent is added in an amount of 0.2 parts or more and 3 parts or less with respect to the translucent member,
The light diffusing agent is arranged near the surface of the light transmissive member, and the surface of the light transmissive member has unevenness caused by the shape of the light diffusing agent,
The surface of the translucent member is either an exposed portion where a part of the light diffusing agent is exposed from the translucent member, or a covered portion where the translucent member covers the light diffusing agent. contains
at least part of the light diffusing agent in the exposed portion and the covered portion is embedded in the translucent member;
The light-emitting device , wherein the translucent member has a surface roughness (Ra) of 0.3 μm or more and 0.6 μm or less . The light emitting device according to claim 1 , wherein the light diffusing agent has a spherical shape . 3. The light-emitting device according to claim 1, wherein the light diffusing agent has a particle size of 65 [mu]m or more and 70 [mu]m or less. The light emitting device according to any one of claims 1 to 3, wherein the translucent member containing the light diffusing agent has a bulk density of 0.1 g/ ^cm3 or more and 0.7 g/ ^cm3 or less. . The light emitting device according to any one of claims 1 to 3, wherein the translucent member containing the light diffusing agent has a bulk density of 0.1 g/ ^cm3 or more and 0.2 g/ ^cm3 or less. . A substrate having a recess,
The light emitting element is provided on the bottom surface of the recess,
The light-emitting device according to any one of claims 1 to 5, wherein the translucent member is provided in the recess to cover the light-emitting element. The light-emitting device according to any one of claims 1 to 6 , wherein the light diffusing agent is white . The light-emitting device according to any one of claims 1 to 7, wherein the translucent member further contains a phosphor. The light emitting device according to claim 8, wherein the phosphor has a specific gravity difference of 0.5 g/ ^cm3 or more and 10 g/ ^cm3 or less with respect to the translucent member. 10. The light emitting device according to claim 9, wherein the light diffusing agent has a higher particle number density than the phosphor on the surface of the light emitting element. a step of mounting the light emitting element in the recess of the substrate;
A step of injecting a hollow translucent member containing a light diffusing agent having a particle size of 50 μm or more into the recess;
a step of floating the light diffusing agent to near the surface of the injected translucent member so as to form irregularities due to the shape of the light diffusing agent on the surface of the translucent member;
a step of curing the translucent member ;
including
In the step of injecting the translucent member, the translucent member is either a silicone resin, a silicone-modified resin, or a silicone hybrid resin,
In the step of injecting the translucent member, the amount of the light diffusing agent added to the translucent member is 0.2 parts or more and 3 parts or less,
In the step of floating the light diffusing agent, the surface of the light transmissive member is an exposed portion where a part of the light diffusing agent is exposed from the light transmissive member, or the light transmissive member is the light diffusing agent. and at least a portion of the light diffusing agent in the exposed portion and the covered portion is buried in the translucent member, the light diffusing agent is levitated,
The method for manufacturing a light-emitting device , wherein the surface roughness (Ra) of the translucent member is 0.3 μm or more and 0.6 μm or less after the step of curing the translucent member . In the step of injecting the light-transmitting member , the light-transmitting member contains a phosphor having a specific gravity difference of 0.5 g/cm ³ or more and 10 g/cm ³ or less with the light- transmitting member together with the light diffusing agent. 12. The method of manufacturing a light-emitting device according to claim 11, wherein the material is injected.

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