Semiconductor light emitting device and method for manufacturing the same

Abstract

To provide a light-emitting device and a method of manufacturing the same capable of reducing heating of a wavelength conversion body during an operation of the light-emitting device, thereby suppressing reduction in optical output of the light-emitting device.SOLUTION: A light-emitting device comprises: a substrate with a wiring electrode; a semiconductor light-emitting element mounted on the wiring electrode of the substrate, having a light-emitting function layer whose top surface is exposed; a wavelength conversion plate placed on the light-emitting function layer of the semiconductor light-emitting element, consisting of a sintered body of phosphor particles and binder particles; and an adhesive layer consisting of a resin medium adhering a light-emitting surface of the light-emitting function layer of the semiconductor light-emitting element with a light-receiving surface of the wavelength conversion plate, and resin particles dispersed in the resin medium. A sintered surface with a recessed part of the sintered body is exposed to the light-receiving surface of the wavelength conversion plate. The resin particles are fitted to the recessed part on the light-receiving surface of the wavelength conversion plate and deformed by compression.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a semiconductor light emitting device including a light emitting element and a method for manufacturing the same. [Background technology]

[0002] Conventionally, a light emitting device has been known that includes a substrate provided with conductive patterns such as terminals and wiring, a light emitting element having a semiconductor light emitting layer mounted on the substrate, and a wavelength converter that converts the wavelength of light emitted from the light emitting element.

[0003] For example, Patent Document 1 discloses a light emitting device having a substrate, a light emitting element mounted on the substrate, a polycrystalline light-transmitting member containing a phosphor as a wavelength conversion material, and a light-guiding member that fixes the light emitting element and the light-transmitting member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-219324 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a light-emitting device such as that described in Patent Document 1, the light-transmitting member is heated by self-heating when the phosphor converts the wavelength of the light emitted by the light-emitting element. When the light-transmitting member is heated, thermal quenching occurs, which reduces the intensity of the fluorescence emitted from the phosphor, and the light output of the semiconductor light-emitting device may decrease.

[0006] The present invention has been made in consideration of the above points, and aims to provide a semiconductor light-emitting device and a manufacturing method thereof that can reduce heating of a wavelength converter during operation of the semiconductor light-emitting device and suppress a decrease in the light output of the semiconductor light-emitting device. [Means for solving the problem]

[0007] The semiconductor light emitting device of the present invention comprises a substrate having wiring electrodes, a semiconductor light emitting element mounted on the wiring electrodes of the substrate and having a light emitting functional layer with an exposed upper surface, a wavelength conversion plate mounted on the light emitting functional layer of the semiconductor light emitting element and consisting of a sintered body of phosphor particles and binder particles, and an adhesive layer made of a resin medium that bonds the light exit surface of the light emitting functional layer of the semiconductor light emitting element and the light incident surface of the wavelength conversion plate and consisting of resin particles dispersed in the resin medium, wherein a sintered surface having a recess of the sintered body is exposed on the front light writing surface of the wavelength conversion plate, and the resin particles fit into the recesses of the front light writing surface of the wavelength conversion plate and are compressed and deformed.

[0008] Furthermore, a manufacturing method for a semiconductor light emitting device according to the present invention includes a substrate preparation step of preparing a substrate having wiring electrodes; an element bonding step of bonding a semiconductor light emitting element onto the wiring electrodes of the substrate; an adhesive application step of applying an adhesive resin consisting of an uncured and fluid thermosetting resin medium and cured thermosetting resin particles dispersed in the resin medium onto an upper surface of the semiconductor light emitting element; a wavelength conversion plate placement step of placing and pressing a wavelength conversion plate consisting of a sintered body in which phosphor particles and binder particles are sintered and having a recess consisting of a sintered surface on a surface facing the semiconductor light emitting element; and a wavelength conversion plate bonding step of thermally curing the resin medium to bond the wavelength conversion plate and the semiconductor light emitting element, wherein in the wavelength conversion plate placement step, the wavelength conversion plate is pressed from above so that the resin particles fit into the recesses of the wavelength conversion plate and are compressed and deformed. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a top view of a light emitting device according to an embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view of a light emitting device according to an embodiment of the present invention. [Diagram 3] FIG. 3 is an enlarged cross-sectional view of a portion A in FIG. 2. [Figure 4] 4 is an enlarged view of a wavelength conversion plate of the light emitting device according to the embodiment of the present invention. [Diagram 5] 5A to 5C are diagrams illustrating a manufacturing flow of the light emitting device according to the embodiment of the present invention. [Figure 6] 5A to 5C are cross-sectional views of the light emitting device according to the embodiment of the present invention during manufacturing. [Figure 7] FIG. 13 is a diagram showing the light output maintenance ratios of light emitting devices according to an example and a comparative example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The following is a detailed description of an embodiment of the present invention. In the following description and the accompanying drawings, substantially the same or equivalent parts are given the same reference numerals. In the following description, the term "material 1 / material 2" refers to a laminated structure in which material 2 is laminated on material 1. Furthermore, the term "material 1-material 2" refers to an alloy of materials 1 and 2. EXAMPLES

[0011] The configuration of a light emitting device 100 according to Example 1 will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a top view of the light emitting device 100 according to Example 1. Fig. 2 is a cross-sectional view taken along line CS-CS of the light emitting device 100 shown in Fig. 1. Fig. 3 is an enlarged SEM image of a light incident surface 40S of a wavelength conversion plate 40.

[0012] The light emitting device 100 as a semiconductor light emitting device includes a substrate 10 having a flat plate portion 11 and a frame body 13, a light emitting element 20 mounted on the flat plate portion 11 of the substrate 10, a wavelength conversion plate 40 mounted on the light emitting element 20, a protection element 30 mounted on the flat plate portion 11 of the substrate 10, and a reflective resin 70 covering the side surfaces of the light emitting element 20 and the wavelength conversion plate 40. In order to illustrate the internal structure of the light emitting device 100, the reflective resin 70 is omitted from FIG. 1.

[0013] The substrate 10 includes a flat plate portion 11 on one surface of a plate-shaped base material on which a first wiring electrode 15 and a second wiring electrode 17 are provided at a distance from each other, and a frame body 13 provided on one surface of the flat plate portion 11 so as to surround the first wiring electrode 15 and the second wiring electrode 17. Hereinafter, one surface of the flat plate portion 11 on which the first wiring electrode 15 and the second wiring electrode 17 are provided will be referred to as the upper surface, and the other surface will be referred to as the lower surface or bottom surface. Also, the upper surface side of the flat plate portion 11 will be referred to as the upper side, and the lower surface side of the flat plate portion 11 will be referred to as the lower side. Also, in the light emitting element 20 etc. mounted on the flat plate portion 11, the surface facing upward will be referred to as the upper surface, and the surface facing downward will be referred to as the lower surface or bottom surface. Also, a recess defined by the upper surface of the flat plate portion 11 and the inner wall surface of the frame body 13 will be referred to as a cavity. The lower surface of the flat plate portion 11 is also the bottom surface of the light emitting device 100.

[0014] The substrate 10 may be a molded body in which the flat plate portion 11 and the frame body 13 are integrally molded, or may be an adhesive body in which the frame body 13, which is made separately, is adhered to the flat plate portion 11.

[0015] The base material of the substrate 10 is, for example, alumina (Al 2 O 3 ), aluminum nitride (AlN), silicon nitride (Si 3 N 4 ) and other oxide and nitride ceramics. When the frame 13 is made separately, the frame 13 may be made of resin, such as epoxy resin, silicone resin, acrylic resin, or polycarbonate resin. In this embodiment, the base material of the substrate 10 is made of AlN, and a molded body in which the flat plate portion 11 and the frame 13 are integrally molded is used. A base material with high thermal conductivity is preferable because it can efficiently dissipate (transfer) heat generated by the wavelength conversion plate 40 and the light emitting element 20 when current is applied to the mounting substrate, thereby maintaining a high light output maintenance rate of the light emitting device 100 described later.

[0016] The first wiring electrode 15 and the second wiring electrode 17 are provided on the upper surface of the flat plate portion 11 of the substrate 10. The first wiring electrode 15 has a rectangular element mounting portion 15A on which the light emitting element 20 is mounted, a bonding portion 15B protruding from one side of the element mounting portion 15A, and a wiring portion 15C extending from one side of the element mounting portion 15A in an island shape. The second wiring electrode 17 is provided opposite the side of the element mounting portion 15A that is not connected to the bonding portion 15B and the wiring portion 15C.

[0017] The first wiring electrode 15 is electrically connected to a first mounting electrode 15D provided on the bottom surface side of the flat plate portion 11 through a via wiring TH1 that penetrates the base material of the flat plate portion 11 from the wiring portion 15C. The second wiring electrode 17 is electrically connected to a second mounting electrode 17D provided on the bottom surface side of the flat plate portion 11 through a via wiring TH2 that penetrates the base material of the flat plate portion 11.

[0018] The first wiring electrode 15 and the second wiring electrode 17 may be made of a metal containing, for example, any one of copper (Cu), tungsten (W), and aluminum (Al). Nickel / gold (Ni / Au) is laminated in order on the portions of the first wiring electrode 15 and the second wiring electrode 17 exposed on the top and bottom surfaces of the flat plate portion 11. In this embodiment, Cu is used for the first wiring electrode 15 and the second wiring electrode 17.

[0019] The light emitting element 20 is a light emitting diode (LED), which is a semiconductor light emitting element. The light emitting element 20 has a structure in which a light emitting functional layer 23 having a thickness of about 4 to 6 μm and including a p-type semiconductor layer, a light emitting layer, and an n-type semiconductor layer laminated thereon is bonded to one side of a conductive support substrate 21 made of silicon (Si) and having a thickness of about 100 μm, via a reflective electrode layer. The light emitting functional layer 23 side of the support substrate 21 is the upper surface of the light emitting element 20, and the opposite side is the lower surface or bottom surface of the light emitting element 20. The surface of the light emitting functional layer 23 opposite the reflective electrode layer, i.e., the upper surface of the light emitting functional layer 23, is the element light emitting surface 23S of the light emitting element 20.

[0020] The light emitting element 20 has a bonding electrode (not shown) on its bottom surface, which is bonded and electrically connected to the element mounting portion 15A of the first wiring electrode 15 via the element bonding layer 50. The light emitting element 20 also has an electrode pad 25 on its top surface, which is electrically connected to the second wiring electrode 17 via a bonding wire BW1. Therefore, the light emitting element 20 emits light when electricity is applied to the first mounting electrode 15D and the second mounting electrode 17D of the substrate 10.

[0021] An LED or an LD (Laser Diode) that emits ultraviolet to blue light can be used as the light emitting element 20. In this embodiment, an LED that emits blue light is used.

[0022] The protection element 30 is, for example, a reverse voltage protection element such as a Zener diode. The protection element 30 operates to protect the light emitting element 20 when an overvoltage is applied to the light emitting element 20 from the outside (for example, static electricity, etc.). The protection element 30 has a bonding electrode (not shown) on the lower surface, which is bonded and electrically connected to the second wiring electrode 17 via an element bonding layer (not shown). The protection element 30 also has an electrode pad (not shown) on the upper surface, which is electrically connected to the bonding portion 15B of the first wiring electrode 15 via a bonding wire BW2.

[0023] The wavelength conversion plate 40 is a wavelength conversion element that converts incident light into light with a longer wavelength and outputs the light. The wavelength conversion plate 40 is plate-shaped and has two main surfaces, a light incident surface 40S which is the lower surface and a light exiting surface 40T which is the upper surface.

[0024] The wavelength conversion board 40 in the present invention is a polycrystalline sintered body formed into a plate shape by sintering phosphor particles and binder particles having a uniform particle size. In this embodiment, each of the phosphor particles and the binder particles has a particle size of about 2 to 10 μm.

[0025] The light incident surface 40S of the wavelength conversion board 40 is a sintered surface in which phosphor particles and binder particles are bonded together, as shown in Fig. 3, and has irregularities according to the shape and particle size of the particles. In addition, facets (thermally stable surfaces of crystals) are formed on many of the particle surfaces of the light incident surface 40S, which is a sintered surface.

[0026] The light entrance surface 40S of the wavelength conversion plate 40 can be described as any of an uneven portion, a concave portion, and a convex portion. Therefore, in the following description, the description will be made based on the surface including the top of the convex portion that becomes the ground portion when the wavelength conversion plate 40 is placed. Therefore, the surface property of the light entrance surface 40S will be described as a surface having a concave portion 40R. That is, the light entrance surface 40S of the wavelength conversion plate 40 has a dome-shaped concave portion 40R formed by a plurality of particle surfaces. In addition, the light entrance surface 40S of the wavelength conversion plate 40 has a polyhedral space formed by the surface of the concave portion 40R, which is a facet.

[0027] The wavelength conversion plate 40 is bonded on the element light emission surface 23S of the light emitting functional layer 23 of the light emitting element 20 via an adhesive layer 60 at the light incident surface 40S side of the wavelength conversion plate 40. The light emission surface 40T of the wavelength conversion plate 40 functions as the light emission surface of the light emitting device 100.

[0028] The wavelength conversion plate 40 may be a polycrystalline sintered body including a YAG-based phosphor doped with cerium (Ce) and / or europium (Eu), a sialon-based phosphor, an oxynitride-based phosphor, or a silicon oxide-based phosphor.

[0029] The wavelength conversion plate 40 used in this embodiment is made of yttrium aluminum garnet (YAG) doped with cerium (Ce) activator. 3 Al 5 O 12 :Ce, abbreviated as YAG:Ce) phosphor particles and alumina (Al 2 O 3 The wavelength conversion board 40 is a polycrystalline sintered body using binder particles made of . ZThe surface roughness (maximum roughness) was 5 μm. The wavelength conversion plate 40 was adjusted to absorb a part of the blue light emitted by the light emitting element 20 and emit yellow light, and the light emitted from the light emitting device 100 became white light.

[0030] The adhesive layer 60 is a resin that transmits light emitted by the light emitting element 20, and bonds the element light emitting surface 23S of the light emitting element 20 and the light incident surface 40S of the wavelength conversion plate 40. The adhesive layer 60 is a resin body obtained by curing an adhesive resin 60M in which resin particles 63, which are cured granular resin with a low elastic modulus, are dispersed in a resin medium 61, which is an uncured liquid resin.

[0031] 4, the adhesive layer 60 is interposed between the element light exit surface 23S of the light-emitting functional layer 23 and the light incident surface 40S of the wavelength conversion plate 40. The resin particles 63 are compressed and deformed to fit into a polyhedral space defined by the recess 40R of the light incident surface 40S of the wavelength conversion plate 40 and the element light exit surface 23S of the light-emitting functional layer 23. The resin medium 61 fills the rest of the space.

[0032] In this way, by compressing and deforming the resin particles 63 by the dome-shaped recesses 40R consisting of multiple particle surfaces of the wavelength conversion plate 40, the density of the resin particles 63 can be increased and the refractive index can be increased. This improves the heat dissipation efficiency of dissipating heat generated in the wavelength conversion plate 40 to the light emitting element 20. In addition, the refractive index difference between the light emitting element 20 and the wavelength conversion plate 40 can be reduced, improving the optical coupling efficiency. Furthermore, by making the recesses 40R of the wavelength conversion plate 40 into facets, the contact area between the wavelength conversion plate 40 and the resin particles 63 can be increased, improving the heat dissipation efficiency and / or the optical coupling efficiency.

[0033] This makes it possible to suppress the temperature quenching phenomenon of the phosphor contained in the wavelength conversion plate 40, and to maintain high optical output of the light emitting device 100. In addition, it is possible to reduce the refractive index difference between the light emitting element 20 and the resin particles 63 and between the resin particles 63 and the wavelength conversion plate 40, and to improve the optical output of the light emitting device 100. In particular, the heat dissipation efficiency of the wavelength conversion plate 40 can be improved by increasing the contact area between the wavelength conversion plate 40, which is the heat source side, and the resin particles 63.

[0034] In the adhesive layer 60 in this embodiment, the same material, thermosetting silicone resin, is used for the resin medium 61 and the resin particles 63. Furthermore, before the adhesive layer 60 is formed, an uncured liquid resin is used for the resin medium 61, and before the adhesive layer 60 is formed, a resin particle 63 that has been heat-cured is used for the resin particles 63.

[0035] The particle diameter (φ) of the resin particles 63 is determined by the surface roughness (R Z The particle diameter (φ) of the resin particles 63 was determined based on the surface roughness (R Z ) can be 1 / 5 (φ1 μm) to 1 / 1 (φ5 μm).

[0036] The particle diameter (φ) of the resin particles 63 is the surface roughness (R Z ), the light emitting functional layer 23 of the light emitting element 20 may be damaged by the protrusions of the light incident surface 40S of the wavelength conversion plate 40. Z ), the resin particles 63 get into the recesses 40R of the light incident surface 40S of the wavelength conversion plate 40, and cannot be compressed and deformed.

[0037] The particle diameter (φ) of the resin particles 63 is determined by the surface roughness (R Z This is because the average surface roughness (Ra: arithmetic mean roughness, or R ZJIS Surface roughness (R Z This is because the surface roughness is 2 / 5 to 3 / 5 of the surface roughness (maximum height roughness).

[0038] The amount of the resin particles 63 added is 1 wt% to 5 wt% in mass percent (wt%, mass of the resin particles 63 / (mass of the resin particles 63+mass of the resin medium 61)×100). This allows one resin particle 63 to be formed so as to contact both the element light output surface 23S of the light emitting functional layer 23 and the light input surface 40S of the wavelength conversion plate 40.

[0039] 2, the reflective resin 70 as a light reflecting portion is filled inside the cavity of the substrate 10 so as to seal the light emitting element 20 and cover the side surface of the wavelength conversion plate 40. The reflective resin 70 is a resin material having reflectivity for the light emitted from the light emitting element 20 and the light emitted from the wavelength conversion plate 40. The reflective resin 70 is filled in the cavity so as to expose the light output surface 40T, which is the upper surface of the wavelength conversion plate 40.

[0040] The reflective resin 70 of this embodiment is a thermosetting silicone resin containing titanium dioxide (TiO 2 ) is dispersed in white resin.

[0041] As described above, according to this embodiment, the adhesive layer 60 that bonds the element light-emitting surface 23S of the light-emitting functional layer 23 of the light-emitting element 20 to the light-entering surface 40S of the wavelength conversion plate 40 contains resin particles 63 of a size that fits into the recess 40R of the light-entering surface 40S of the wavelength conversion plate 40 and is compressed and deformed. This enables the heat generated in the wavelength conversion plate 40 to be efficiently dissipated (transferred) to the light-emitting element 20.

[0042] Next, an example of a manufacturing procedure for the light emitting device 100 will be described with reference to FIGS.

[0043] Fig. 5 is a diagram showing a manufacturing flow of the light emitting device 100 according to the embodiment of the present invention. Fig. 6 is a cross-sectional view of the light emitting device 100 at the stage where the wavelength conversion plate 40 is placed (before pressing) in step S15 of the manufacturing procedure shown in Fig. 5. Fig. 6 is an enlarged cross-sectional view of part A of the light emitting device 100 shown in Fig. 2.

[0044] The substrate preparation step is a step of preparing a substrate 10 as shown in Fig. 1 and Fig. 2 (step S11). In the prepared substrate 10, a first wiring electrode 15 and a second wiring electrode 17 are formed on the upper surface of a flat plate portion 11 which is the bottom surface of the cavity, and a frame body 13 which becomes the side wall of the cavity is provided on the upper surface of the flat plate portion 11. The first wiring electrode 15 has a rectangular element mounting portion 15A large enough to mount a light emitting element 20, a bonding portion 15B protruding from one side which defines the outer shape of the element mounting portion 15A, and a wiring portion 15C protruding from the other side in an island shape. The second wiring electrode 17 is provided to face the side of the element mounting portion 15A on which the bonding portion 15B and the wiring portion 15C are not provided.

[0045] The element bonding process is a process of bonding a light emitting element 20 to the upper surface of the element mounting portion 15A of the first wiring electrode 15, and bonding a protective element 30 to the end of the upper surface of the second wiring electrode 17, as shown in Figures 1 and 2 (step S12).

[0046] First, gold-tin (Au-Sn) paste is applied to the element mounting portion 15A of the first wiring electrode 15 and the end of the upper surface of the second wiring electrode 17. Next, bonding electrodes (not shown) provided on the bottom surfaces of the light emitting element 20 and the protective element 30 are pressed and temporarily attached onto the applied Au-Sn paste. The substrate 10 in this state is heated to 300°C to melt and solidify the Au-Sn paste, thereby fixing and electrically connecting the light emitting element 20 to the element mounting portion 15A and the protective element 30 to a predetermined location at the end of the second wiring electrode 17.

[0047] The wire bonding process is a process of connecting the electrode pad 25 of the light-emitting element 20 to the second wiring electrode 17, and the electrode pad of the protection element 30 to the bonding portion 15B of the first wiring electrode 15 with bonding wires BW1 and BW2, respectively, as shown in FIG. 1 (step S13).

[0048] First, one end of a gold (Au) wire is connected to the upper surface of the second wiring electrode 17 and raised upward to the height of the electrode pad 25 of the light emitting element 20. Next, the wire is bent so as to be horizontal with the upper surface of the flat plate portion 11 and extended to the electrode pad 25 of the light emitting element 20, and the other end of the Au wire is connected to the electrode pad 25 to form a bonding wire BW1. Also, one end of the Au wire is connected to an electrode pad provided on the upper surface of the protection element 30, raised upward, looped, and extended to the bonding portion 15B of the first wiring electrode 15. Next, the other end of the Au wire is connected to the bonding portion 15B to form a bonding wire BW2.

[0049] The adhesive application step is a step of applying an adhesive resin 60M that becomes the adhesive layer 60 to the element light-emitting surface 23S of the light-emitting functional layer 23 of the light-emitting element 20 (step S14).

[0050] First, 2 wt % of resin particles 63, which are cured spherical silicone resin with a particle diameter of φ2 μm, is added to a resin medium 61M, which is uncured silicone resin, to prepare an adhesive resin 60M.

[0051] Next, a predetermined amount of adhesive resin 60M is dropped from a dropping nozzle onto the element light emitting surface 23S of the light emitting functional layer 23 of the light emitting element 20. When the adhesive resin 60M has spread to cover 40% to 60% of the area of ​​the element light emitting surface 23S of the light emitting functional layer 23, this process is terminated.

[0052] After application, the adhesive resin 60M containing 1 wt % to 5 wt % of the resin particles 63 easily wets and spreads over the element light emitting surface 23S of the light emitting functional layer 23. In addition, since the resin medium 61M of the adhesive resin 60M and the resin particles 63 are made of the same type of silicone resin, the resin particles 63 can wet and spread without settling or agglomerating after application.

[0053] In this manner, this application step is not only for applying the adhesive resin 60M to the element light-emitting surface 23S of the light-emitting functional layer 23, but also serves as a preliminary step for uniformly spreading the resin particles 63 contained in the adhesive resin 60M.

[0054] In addition, if a method is used that can uniformly apply the resin particles 63 to the element light emission surface 23S of the light-emitting functional layer 23, such as a method of applying it with a spray gun or a method of applying adhesive resin 60M diluted with a solvent to the entire surface and then drying the solvent, the amount of resin particles 63 added can be 5 wt% or more.

[0055] The wavelength conversion plate mounting step is a step of mounting the wavelength conversion plate 40 on the adhesive resin 60M applied onto the element light emitting surface 23S of the light emitting functional layer 23 of the light emitting element 20 (step S15).

[0056] The wavelength conversion plate 40 is placed so that the light incident surface 40S of the wavelength conversion plate 40 is in contact with the upper surface of the adhesive resin 60M that has been applied to the element light output surface 23S of the light emitting functional layer 23 and spread to a predetermined area in step S14. At this time, the adhesive resin 60M spreads between the element light output surface 23S of the light emitting functional layer 23 and the light incident surface 40S of the wavelength conversion plate 40 in a state in which the spherical resin particles 63 are dispersed in the resin medium 61, as shown in FIG.

[0057] After that, the wavelength conversion plate 40 is subjected to a pressure of about 40 g / mm 2 The light-emitting functional layer 23 was pressed with a load of 0.5 sec for about 0.5 seconds. By this operation, as shown in Fig. 4, the adhesive resin 60M spreads without any gaps between the element light-emitting surface 23S of the light-emitting functional layer 23 and the light-entering surface 40S of the wavelength conversion plate 40. In addition, the resin particles 63 are compressed and deformed while being accommodated in the recesses 40R of the light-entering surface 40S of the wavelength conversion plate 40, so that the element light-emitting surface 23S of the light-emitting functional layer 23 and the light-entering surface 40S of the wavelength conversion plate 40 are closely attached to each other via the adhesive resin 60M.

[0058] In this embodiment, the elastic modulus of the silicone resin of the resin particles 63 is 1 to 2 MPa, the elastic modulus of the alumina crystals that are the binder of the wavelength conversion plate 40 is 300 to 400 GPa, and the elastic modulus of GaN that is the main composition of the light emitting functional layer 23 of the light emitting element 20 is 150 to 200 GPa. In this way, by making the resin particles 63 softer than the wavelength conversion plate 40 and the light emitting functional layer 23, the wavelength conversion plate 40 can be made to have a mass of about 40 g / mm 2When the resin particles 63 are subjected to a pressing process, the resin particles 63 are compressed and deformed, thereby increasing the density of the resin particles 63. At the same time, the resin particles 63 also function as a pressing buffer material, and can prevent damage to the light-emitting functional layer 23 due to pressing. Such an effect is exhibited well when the elastic modulus of the resin particles 63 is 1 to 10 MPa.

[0059] The wavelength conversion plate 40 of this embodiment is a plate material made of a sintered body obtained by kneading YAG:Ce phosphor raw material and alumina binder particles into a sheet shape and sintering the mixture. The light incident surface 40S of the wavelength conversion plate 40 thus formed has a recess 40R formed of a sintered surface having facets made of phosphor particles and binder particles, as shown in FIG. 3. The surface roughness R Z was 5 μm.

[0060] The wavelength conversion board bonding step is a step of heating the substrate 10 after step S15 to harden the resin medium 61M of the adhesive resin 60M to form the adhesive layer 60 (step S16).

[0061] The light emitting surface 23S of the light emitting functional layer 23 of the light emitting element 20, the light incident surface 40S of the wavelength conversion plate 40, the resin particles 63 that are in close contact with both surfaces and compressed and deformed, and the uncured resin medium 61M that fills the remaining space were cured by heat treatment at 150°C for 15 minutes.

[0062] This operation formed an adhesive layer 60 that holds the resin particles 63 in a compressed and deformed state in close contact with the element light-emitting surface 23S of the light-emitting functional layer 23 and the light-entering surface 40S of the wavelength conversion plate 40. That is, this step is a step of fixing the resin particles 63 that have been compressed and deformed to have a higher density than the resin medium 61. In other words, this is a step of forming a resin body having a high-density portion in the portion in contact with the element light-emitting surface 23S of the light-emitting functional layer 23 and the light-entering surface 40S of the wavelength conversion plate 40.

[0063] The refractive index of the resin particles 63 with such increased density becomes higher than that of the medium resin. Specifically, the refractive index of the silicone resin after curing, which is the resin medium 61, is about 1.4, and the refractive index of the resin particles 63 is a value of about 1.4 or more. Therefore, the difference in refractive index between the refractive index (about 2.5) of GaN, which is the main composition of the light-emitting functional layer 23, and the refractive index (about 1.7) of alumina, which is the binder of the wavelength conversion plate 40, can be reduced, and the light output of the light-emitting device 100 can be improved.

[0064] The coating member filling step is a step of filling a cavity formed by the upper surface of the flat plate portion 11 and the inner wall surface of the frame 13 with a reflective resin 70, as shown in FIG. 2 (step S17).

[0065] First, titanium oxide (TiO 2 The silicone resin in which the nanoparticles are dispersed is injected into the cavity of the substrate 10 so as to cover the outer surface of the wavelength conversion plate 40 and expose the light output surface 40T (upper surface). The silicone resin is then cured by heat treatment at 150° C. for 120 minutes to form the reflective resin 70.

[0066] By this operation, the first and second wiring electrodes 15 and 17 provided on the bottom surface of the cavity of the substrate 10, the light emitting element 20, the protective element 30, the bonding wires BW1 and BW2, and the side surfaces of the wavelength conversion plate 40 are sealed.

[0067] As described above, according to the manufacturing method of this embodiment, the manufacturing can be performed by carrying out the steps S11 to S17. In particular, the adhesive resin 60M mixed with the cured resin particles 63 is adjusted, the adhesive resin 60M is uniformly spread between the element light output surface 23S of the light emitting element 20 and the light incident surface 40S of the wavelength conversion plate 40, and the wavelength conversion plate 40 is pressed. This makes it possible to compress and deform the resin particles 63 mixed in the adhesive resin 60M and fit them into the polyhedral space formed by the surface of the recess 40R of the light incident surface 40S of the wavelength conversion plate 40.

[0068] Next, Example 2, Example 3, and Comparative Example will be described. Examples 2, 3, and Comparative Example have the same substrate 10, light emitting element 20, wavelength conversion plate 40, reflective resin 70, etc. as the Examples, except for the amount of resin particles 63 added to the adhesive layer 60, and the absence of resin particles 63. Therefore, only the differences will be described. EXAMPLES

[0069] In the light emitting device of Example 2, the amount of resin particles 63 added to the adhesive layer 60 is reduced from 2 wt % to 1 wt %. All other aspects are the same. EXAMPLES

[0070] In the light emitting device of Example 3, the amount of resin particles 63 added to the adhesive layer 60 is increased from 2 wt % to 5 wt %. All other points are the same. Comparative Example

[0071] In the light emitting device of the comparative example, the amount of resin particles 63 added to the adhesive layer 60 is changed from 2 wt % to 0 wt %, i.e., no addition is made. All other aspects are the same. In addition, the pressing force of the wavelength conversion board 40 in step S15 of the manufacturing method is set to about 50 g / mm 2 from about 10g / mm 2 This operation prevents the light emitting functional layer 23 from being damaged by the pressure of the light incident surface 40S of the wavelength conversion plate 40.

[0072] Next, the light emitting characteristics of the light emitting devices of Example, Example 2, Example 3, and Comparative Example were compared. Here, the light emitting device 100 of Example will be referred to as Sample 1, the light emitting device of Example 2 as Sample 2, the light emitting device of Example 3 as Sample 3, and the light emitting device of Comparative Example as Sample 4.

[0073] FIG. 7 is a diagram showing the light emission characteristics of a light emitting device. The horizontal axis is the element output of the light emitting device. Specifically, it is the light output (mW) when a predetermined current is applied to the light emitting device at the stage where step S13 is completed. Also, the vertical axis is the light output maintenance rate (%) of the light emitting device after manufacture. Specifically, it is a value obtained by dividing the luminous flux value (lm: lumen) when a predetermined current is applied for 20 ms (milliseconds) as a reference (denominator) by the luminous flux value (lm) when a current is applied for 200 ms (milliseconds), and multiplying the result by 100. This value represents the magnitude of change in the light emission characteristics due to heat generation of the light emitting device, and the closer the value is to 100%, the less the effect of heat is.

[0074] The light emitting element 20 used in the light emitting devices of this embodiment and the comparative example has an emission wavelength (λ) of 448 nm to 449 nm. The wavelength conversion plate 40 is a phosphor plate in which YAG:Ce phosphor particles and alumina binder particles are sintered. As shown in FIG. 3, the particle arrangement of the light incident surface 40S is uniform, and the roughness (R Z ) is 5 μm.

[0075] The element output and light output maintenance rate of Samples 1 to 4 prepared using such components were 1463 mW and 95.5% for Sample 1 (Example 1), 1463 mW and 95.5% for Sample 2 (Example 2), 1460 mW and 95.0% for Sample 3 (Example 3), and 1454 mW and 94.5% for Sample 4 (Comparative Example).

[0076] It can be seen that the light output maintenance rates of Samples 1, 2, and 3 of the embodiment are 0.5% to 1.0% higher than that of Sample 4 of the comparative example. This difference in light output maintenance rate is further increased by, for example, extending the power supply time. In this way, the light emitting device of the embodiment can reduce the thermal influence compared to the light emitting device of the comparative example, making it possible to maintain high light output.

[0077] Even if hard particles such as glass particles are added to the resin medium 61 instead of the resin particles 63, the effect of this embodiment cannot be obtained. This is probably because hard particles such as glass particles cannot be compressed and deformed to fit into the recess 40R of the light incident surface 40S of the wavelength conversion plate 40.

[0078] As described above, according to the light emitting device 100 and the manufacturing method thereof of the present invention, it is possible to provide a light emitting device 100 and a manufacturing method thereof that can reduce heating of the wavelength converter during operation of the light emitting device 100 and maintain high optical output of the light emitting device 100. Also, according to the light emitting device 100 and the manufacturing method thereof, it is possible to provide a light emitting device 100 and a manufacturing method thereof that can reduce optical coupling loss of the light emitting device 100 and increase the optical output of the light emitting device 100.

[0079] Although the embodiments of the present invention have been described above, these are merely examples and the present invention is not limited to these examples.

[0080] For example, in this embodiment, the light emitting element 20 is an LED, but the light emitting element 20 may be a surface emitting laser. In the manufacturing method, the adhesive resin 60M that becomes the adhesive layer 60 is hardened by the heat treatment in the wavelength conversion plate bonding step, but this step may be omitted and the adhesive resin 60M may be hardened by the heat treatment in the subsequent coating member filling step.

[0081] Thus, the described embodiments are not intended to limit the scope of the invention. The described embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These modifications are also included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0082] 100 Light emitting device 10 Substrate 11 Flat plate part 13 Frame 15 First wiring electrode 17 Second wiring electrode 20 Light emitting element 21 Support substrate 23 Light-emitting functional layer 25 Electrode Pads 30 Protection elements 40 Wavelength conversion plate 50 Element bonding layer 60 Adhesive layer 70 Reflective Resin

Claims

1. A substrate having wiring electrodes; a semiconductor light emitting element having a light emitting functional layer placed on the wiring electrode of the substrate and having an exposed upper surface; a wavelength conversion plate placed on the light emitting functional layer of the semiconductor light emitting element and made of a sintered body of phosphor particles and binder particles; an adhesive layer including a resin medium that bonds a light output surface of the light emitting functional layer of the semiconductor light emitting element and a light input surface of the wavelength conversion plate and resin particles dispersed in the resin medium; the resin particles and the resin medium are both silicone resins; a sintered surface of the sintered body having a recess is exposed on a front writing surface of the wavelength conversion plate, a wavelength conversion plate that converts the resin particles into a light-emitting material having a thickness larger than that of the wavelength conversion plate;

2. 2. The semiconductor light emitting device according to claim 1, wherein the wavelength conversion plate has a facet on the light incident surface.

3. 3. The semiconductor light emitting device according to claim 1, wherein a polyhedral space is formed by a surface of the recess on the front writing surface of the wavelength conversion plate.

4. 4. The semiconductor light emitting device according to claim 1, wherein the resin particles have at least one of a density and a refractive index higher than that of the resin medium.

5. 5. The semiconductor light emitting device according to claim 1, wherein an average particle size of the resin particles is 1 / 5 to 1 / 1 of a surface roughness (Rz) of the wavelength conversion plate.

6. A semiconductor light-emitting device as described in claim 5, characterized in that the surface roughness (Rz) of the wavelength conversion plate is 5 μm.

7. A semiconductor light-emitting device described in any one of claims 1 to 6, characterized in that the amount of the resin particles added is 1 wt% to 5 wt% by mass percent.

8. a substrate preparation step of preparing a substrate having wiring electrodes; an element bonding step of bonding a semiconductor light emitting element onto the wiring electrode of the substrate; an adhesive application step of applying an adhesive resin, which is composed of an uncured thermosetting resin medium having fluidity and cured thermosetting resin particles dispersed in the resin medium, onto an upper surface of the semiconductor light emitting element; a wavelength conversion plate mounting step of mounting and pressing a wavelength conversion plate made of a sintered body of phosphor particles and binder particles, the wavelength conversion plate having a recess formed of a sintered surface on a surface facing the semiconductor light emitting element, on the adhesive resin; a wavelength conversion plate bonding step of bonding the wavelength conversion plate and the semiconductor light emitting element by thermally curing the resin medium, the resin particles and the resin medium are both silicone resins; a wavelength conversion plate mounting step for mounting the wavelength conversion plate on the substrate, the wavelength conversion plate being pressed from above so that the resin particles fit into the recesses of the wavelength conversion plate and are compressed and deformed.

9. 9. The method for manufacturing a semiconductor light emitting device according to claim 8, wherein the resin particles are dispersed in the resin medium at a mass concentration of 1 wt % to 5 wt %.

10. 10. The method for manufacturing a semiconductor light emitting device according to claim 8, wherein the resin particles having a modulus of elasticity smaller than those of the semiconductor light emitting element and the wavelength conversion plate are dispersed in the resin medium.

Images