Light emitting device

Abstract

To provide a light emitting device that is excellent in heat radiation property.SOLUTION: A light emitting device comprises: a first conductive member 21 and a second conductive member 22 that each include an upper face 20U, a lower face 20D on the opposite side of the upper face, and a side face 20S between the upper face and the lower face; solder 30 that is arranged on the upper face of the first conductive member and the upper face of the second conductive member; a light emitting element 10 that is joined by the solder to the upper face of the first conductive member and the upper face of the second conductive member; a translucent member 40 that is arranged on an upper face of the light emitting element; and a covering member 50 that covers the upper face of the first conductive member, the upper face of the second conductive member, and a side face of the light emitting element. The side face of the first conductive member includes a first concave surface C1 that continues from the upper face, and a second concave surface C2 that is located below the first concave surface. The solder continuously covers the upper face of the first conductive member and at least part of a portion of the first concave surface. The covering member further covers the solder that covers the first concave surface and at least part of the second concave surface.SELECTED DRAWING: Figure 1B

Description

Technical Field

[0001] The present disclosure relates to a light-emitting device.

Background Art

[0002] A light-emitting device in which a light-emitting element is placed on a conductive member is known. (For example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An embodiment according to the present disclosure aims to provide a light-emitting device with excellent heat dissipation performance.

Means for Solving the Problems

[0005] The light-emitting device according to the embodiment includes a first conductive member and a second conductive member each having an upper surface, a lower surface opposite to the upper surface, and a side surface between the upper surface and the lower surface, solders disposed on the upper surfaces of the first conductive member and the second conductive member, a light-emitting element joined to the upper surfaces of the first conductive member and the second conductive member with the solders, a light-transmissive member disposed on the upper surface of the light-emitting element, a covering member covering the upper surfaces of the first conductive member, the second conductive member, and the side surface of the light-emitting element, and is provided with the side surface of the first conductive member includes a first concave surface continuous from the upper surface and a second concave surface located below the first concave surface, the solder continuously covers at least a part of the upper surface of the first conductive member and a part of the first concave surface, The covering member further covers the solder covering the first concave surface and at least a part of the second concave surface.

Advantages of the Invention

[0006] According to the embodiment of the present disclosure, a light-emitting device excellent in heat dissipation can be provided.

Brief Description of the Drawings

[0007]

Figure 1A

Figure 1B

Figure 1C

Figure 1D

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Figure 4E

Figure 4F

Figure 4G

Figure 4H

Figure 5A

Figure 5B

Figure 5C

Figure 5D

Figure 6A

Figure 6B

Figure 6C

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, terms indicating specific directions or positions (for example, "up", "down", "right", "left", and other terms including those terms) are used as necessary. The use of those terms is for facilitating the understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meanings of those terms. Further, a plan view means viewing directly or through a perspective from the top surface or the bottom surface. Also, parts denoted by the same reference numerals appearing in a plurality of drawings indicate the same parts or members.

[0009] As shown in FIGS. 1A and 1B, the light-emitting device 100 according to the embodiment includes a conductive member 20, at least one light-emitting element 10 disposed on the conductive member 20 via a solder 30, a light-transmissive member 40 disposed on the light-emitting element 10, and a covering member 50 that covers the side surface of the light-emitting element 10. Specifically, the conductive member 20 includes a first conductive member 21 and a second conductive member 22. The first conductive member 21 and the second conductive member 22 each include an upper surface 20U, a lower surface 20D opposite to the upper surface 20U, and a side surface 20S between the upper surface 20U and the lower surface 20D. The side surface 20S of the first conductive member 21 includes a first concave surface C1 continuous from the upper surface 20U and a second concave surface C2 located below the first concave surface C1. The solder 30 is disposed so as to continuously cover at least a part of the upper surface 20U of the first conductive member 21 and a part of the first concave surface C1. The light-emitting element 10 is joined to the upper surface 20U of the first conductive member 21 and the upper surface 20U of the second conductive member 22 via the solder 30. The light-transmissive member 40 is disposed on the upper surface of the light-emitting element 10. The covering member 50 covers the upper surface 20U of the first conductive member 21, the upper surface 20U of the second conductive member 22, and the side surface of the light-emitting element 10. The covering member 50 further covers the solder 30 covering the first concave surface C1 and at least a part of the second concave surface C2.

[0010] By the solder 30 continuously covering the upper surface 20U of the first conductive member 21 and the first concave surface C1, the contact area between the first conductive member 21 and the solder 30 increases. Thereby, heat from the light-emitting element 10 can be efficiently released, and a light-emitting device excellent in heat dissipation can be obtained. The light-emitting element 10 has substantially the entire surface as a light-emitting region in plan view, and particularly, heat due to light emission easily accumulates in the portion sandwiched between the electrodes 12. And, the side where the pair of electrodes 12 face each other, that is, the vicinity of the center of the light-emitting element 10 is a portion where heat dissipation is required. Therefore, by extending the solder 30 from the upper surface 20U to the side surface 20S of the conductive member 20, it becomes possible to efficiently spread heat from the side where the pair of electrodes 12 face each other to the conductive member 20.

[0011] Hereinafter, each member will be described in detail.

[0012] (Conductive Member) The conductive member 20 including the first conductive member 21 and the second conductive member 22 mainly functions as an electrode of the light-emitting device 100. When there is no need to distinguish between the first conductive member 21 and the second conductive member 22 for description, they are simply described as "conductive member" without adding the first and second. Also, as shown in FIGS. 4D to 4F, for example, the conductive member 20 may include three or more conductive members. Furthermore, the conductive member 20 can include a conductive member that does not contribute to energization. The conductive member that does not contribute to energization can function as a heat dissipation member, for example.

[0013] The conductive member 20 is a patterned plate-shaped metal member having a predetermined shape, and has a base material as a base and a plating layer formed on its surface.

[0014] Examples of the material of the base material include metals such as Cu, Al, Ag, Au, Zn, Cr, W, Co, No, Rh, Ru, or alloys thereof. These may be single layers or laminated structures (for example, clad materials). A metal plate containing 90% or more of Cu as the main component is preferred. Also, non-metals such as Si and P may be included as trace elements.

[0015] The thickness of the base material is preferably about 100 μm to 800 μm, and more preferably about 300 μm to 800 μm.

[0016] As the plating layer disposed on the surface of the base material, a material having a higher reflectivity than the base material is preferred. For example, the plating layer includes Ni, Ag, Au, Pt, Pd, Al, W, Mo, Ru, Rh, etc. Examples of the laminated structure include Ni / Pd / Au, Ni / Pt / Au, Ni / Au / Ag, etc., and among them, Ni / Pd / Au is preferred.

[0017] The thickness of the plating layer is preferably about 1 μm to 10 μm, and more preferably 1.5 μm to 6 μm.

[0018] The conductive member 20 includes an upper surface 20U, a lower surface 20D opposite to the upper surface 20U, and a side surface 20S between the upper surface 20U and the lower surface 20D. The side surfaces 20S of the first conductive member 21 and the side surfaces 20S of the second conductive member 22 are provided with a first concave surface C1 continuous from the upper surface 20U and a second concave surface C2 located below the first concave surface C1 on the side surfaces 20S arranged opposite to each other. In both the first conductive member 21 and the second conductive member 22, the concave surface continuous from the upper surface 20U is referred to as the first concave surface C1, and the concave surface located below the first concave surface C1 is referred to as the second concave surface C2. The first concave surface C1 and the second concave surface C2 can be arranged continuously. Alternatively, they can be arranged separately with a flat portion in between. The side surface of the conductive member 20 is exposed to the outside on the side surface of the light-emitting device 100. The side surface continuous from the upper surface 20U of the conductive member 20 exposed to the outside is not a curved surface but a flat surface.

[0019] The upper surfaces 20U of the first conductive member 21 and the second conductive member 22 are flat surfaces arranged so as to be located on the same plane and are surfaces not exposed to the outside. Also, as shown in FIGS. 4G and 4H, the upper surfaces 20U of the first conductive member 21 and the second conductive member 22 may each be provided with a processed portion 20P. The processed portion 20P is concave, convex, or concavo-convex in a cross-sectional view. The height or depth of the processed portion 20P from the flat portion of the upper surface 20U of the conductive member 20 can be, for example, 1 μm to 10 μm. The width of the processed portion 20P (the width in the direction orthogonal to the extending direction) can be, for example, 10 μm to 100 μm in a top view.

[0020] The processed portion 20P can be formed, for example, by irradiating a laser beam onto the upper surface 20U which is a flat surface. Also, the processed portion 20P can be formed by pressing with a mold or the like, etching, blasting, or the like. For example, when the surface of the base material mainly composed of Cu of the conductive member 20 has a plating layer with a laminated structure having Au on the outermost surface and Ni in the underlying layer, it is preferable that Ni is exposed in the processed portion 20P. Thereby, it is possible to efficiently reduce the flow of the solder 30 into an unintended area.

[0021] In the example shown in FIG. 4G, the light-emitting element 10 and the protective element 70 are arranged on the same plane, and as the processing portion 20P, the processing portion 20P1 around the light-emitting element 10 and the processing portion 20P2 around the protective element 70 are provided. By providing the processing portion 20P, it is possible to reduce the flow of the solder 30 into an unintended area.

[0022] The processing portion 20P1 is arranged along three sides of the outer periphery of the electrode 12 of the light-emitting element 10 excluding the side where the first conductive member 21 and the second conductive member 22 face each other. As shown in FIG. 4G, the processing portion 20P1 can be arranged such that the portion along the short side of the rectangular electrode 12 and the portion along the long side are continuous. Also, in the portion along the long side of the electrode 12, it may be continuous or, as shown in FIG. 4G, a part may be separated. By arranging the processing portion 20P so as to surround the outer periphery of the pair of conductive members 20 in this way, it is possible to reduce the movement of the light-emitting element 10 to an unintended position when the solder 30 melts. Thereby, the light-emitting element 10 can be arranged with high positional accuracy.

[0023] Further, the processing portion 20P2 extends in a direction parallel to the short side of the electrode 12 of the light-emitting element 10 and is arranged so as to sandwich the protective element 70. Thereby, when the solder 30 melts, it is possible to reduce the movement of the protective element 70 toward the light-emitting element 10 side. In particular, in a top view, by arranging the processing portion 20P2 disposed between the light-emitting element 10 and the protective element 70 to a position away from the outer periphery of the protective element 70, it is possible to further reduce the movement of the protective element 70 toward the light-emitting element 10 side when the solder 30 melts. Also, the processing portion 20P2 may be arranged so as to surround the outer periphery of the protective element 70 in a top view, similarly to the processing portion 20P1.

[0024] The lower surfaces 20D of the first conductive member 21 and the second conductive member 22 are flat surfaces arranged to be located on the same plane and are surfaces exposed to the outside. The light-emitting element 10 is arranged to straddle the upper surface 20U of the first conductive member 21 and the upper surface 20U of the second conductive member 22. That is, below the light-emitting element 10, the side surfaces 20S of the first conductive member 21 and the side surfaces 20S of the second conductive member 22 are arranged to face each other. And, among the side surfaces 20S of the conductive member 20, at least the side surface 20S of the first conductive member 21 on the side surfaces 20S facing each other includes a first concave surface C1 continuous from the upper surface 20U and a second concave surface C2 located below the first concave surface C1.

[0025] The distance between the electrodes 12 of the light-emitting element 10 can be made smaller than the distance between the upper ends C11 of the first concave surface C1 of the first conductive member 21 and the upper ends C11 of the first concave surface C1 of the second conductive member 22. Since the solder 30 contacts the entire surface of the electrode 12, even if the distance between the electrodes 12 is made smaller, the heat generated at the portion sandwiched between the electrodes 12 via the solder 30 can be sufficiently transmitted to the conductive member, so that the heat dissipation performance can be improved.

[0026] The first concave surface C1 and the second concave surface C2 may be arranged on only one of the first conductive member 21 and the second conductive member 22, or may be arranged on both. Preferably, the first concave surface C1 and the second concave surface C2 are arranged on both the first conductive member 21 and the second conductive member 22. Hereinafter, the case where the first conductive member 21 and the second conductive member 22 each include the first concave surface C1 and the second concave surface C2 will be described.

[0027] The upper end C11 of the first concave surface C1 is located at the end of the upper surface 20U of the conductive member 20. As shown in FIG. 1B, the upper surface 20U of the conductive member 20 may have a curved surface in a cross-sectional view for the portion including the end, or the portion including the end may be a flat surface. The lower end C12 of the first concave surface C1 is located between the upper surface 20U and the lower surface 20D of the conductive member 20. The distance (vertical distance) from the upper surface 20U to the lower end C12 of the first concave surface C1 can be, for example, at a position of 10% to 90% of the distance from the upper surface 20U to the lower surface 20D (the thickness of the conductive member). The distance (vertical distance) from the upper surface 20U to the lower end C12 of the first concave surface C1 of the first conductive member 21 and the lower end C12 of the first concave surface C1 of the second conductive member 22 may be the same or different.

[0028] The lower end C12 of the first concave surface C1 of the first conductive member 21 can be located closer to the second conductive member 22 side than the upper end C11 of the first concave surface C1, as shown in FIG. 3 for example. Also, the upper end C11 of the first concave surface C1 of the first conductive member 21 can be located closer to the second conductive member 22 side than the lower end C12 of the first concave surface C1. Alternatively, the upper end C11 and the lower end C12 of the first concave surface C1 of the first conductive member 21 and / or the second conductive member 22 may coincide in a plan view, as shown in FIG. 1B for example.

[0029] The upper end C21 of the second concave surface C2 of the first conductive member 21 may coincide with the lower end C12 of the first concave surface C1, or may be arranged via a flat portion or the like from the lower end C12 of the first concave surface C1. In the example shown in FIG. 1B, the lower end C12 of the first concave surface C1 and the upper end C21 of the second concave surface C2 coincide and are located at the tip of the portion having a curved surface in a cross-sectional view. Also, in the example shown in FIG. 3, the lower end C12 of the first concave surface C1 and the upper end C21 of the second concave surface C2 coincide and are located at the tip of the portion having a sharp shape in a cross-sectional view.

[0030] When a flat portion is provided between the first concave surface C1 and the second concave surface C2, the angle of the flat portion can be an angle perpendicular or inclined to the upper surface 20U of the first conductive member 21. Either one or both of the first conductive member 21 and the second conductive member 22 can be provided with a flat portion. When a flat portion is provided, the vertical distance from the upper surface 20U of the conductive member 20 at the upper end C21 of the second concave surface C2 can be, for example, 10% to 90% of the distance from the upper surface 20U to the lower surface 20D (the thickness of the conductive member).

[0031] The lower end C22 of the second concave surface 2 of the first conductive member 21 can be located closer to the second conductive member 22 side than the upper end C21 of the second concave surface C2. Also, as shown in FIG. 1B, the upper end C21 of the second concave surface C2 of the first conductive member 21 can be located closer to the second conductive member 22 side than the lower end C22 of the second concave surface C2. Alternatively, the upper end C21 and the lower end C22 of the second concave surface 2 of the first conductive member 21 and / or the second conductive member 22 may coincide in a plan view.

[0032] (Solder) The solder 30 is a conductive member that electrically connects the pair of positive and negative electrodes 12 provided in the light-emitting element 10 and the conductive member 20. One of the electrodes 12 of the light-emitting element 10 is electrically joined to the first conductive member 21 via the solder 30, and the other of the electrodes 12 of the light-emitting element 10 is electrically joined to the second conductive member 22 via the solder 30. The solder 30 preferably contacts the entire lower surface of the electrode 12 of the light-emitting element 10. The solder 30 can have a thickness of 5 μm to 20 μm between the light-emitting element 10 and the upper surface 20U of the conductive member 20.

[0033] As shown in Fig. 3, the solder 30 continuously covers the upper surface 20U of the conductive member 20 and at least a part of the first concave surface C1 continuous from the upper surface 20U. Thereby, the heat dissipation can be improved as compared with the case where the solder 30 covers only the upper surface 20U. Further, as shown in Fig. 1B or Fig. 2, the solder 30 may also continuously cover a part of the second concave surface C2 of the conductive member 20. Thereby, the heat dissipation can be further improved. The thickness of the solder covering the upper surface 20U of the conductive member 20 is thicker than the thickness of the solder 30 covering the first concave surface C1. The thickness of the solder 30 covering the first concave surface C1 can be, for example, 1 μm to 20 μm.

[0034] The solder 30 may cover only the upper surface 20U and the first concave surface C1 as shown in Fig. 3 in both the first conductive member 21 and the second conductive member 22, or may cover the upper surface 20U, the first concave surface C1 and the second concave surface C2 as shown in Fig. 2. Alternatively, as shown in Fig. 1B, the solder 30 may cover the upper surface 20U and the first concave surface C1 of the second conductive member 22 and may also cover the upper surface 20U, the first concave surface C1 and the second concave surface C2 of the first conductive member 21. The solder 30 preferably covers all of the first concave surface C1 located below the light-emitting element 10. Further, the solder 30 preferably covers a region of 1 μm to 20 μm between the upper end C21 and the lower end C22 of the second concave surface C2 located below the light-emitting element 10. The solder 30 preferably covers a portion away from the lower end C22 of the second concave surface C2. In other words, the solder 30 preferably does not reach the lower surface 20D of the conductive member 20.

[0035] In plan view, the entire solder 30 is disposed at a position overlapping the light-emitting element 10. However, a part of the solder 30 may not overlap the light-emitting element 10, that is, there may be a portion protruding from the light-emitting element 10.

[0036] Examples of the material of the solder 30 include Au-Sn, Sn-Ag-Cu, Sn-Cu, Sn-Sb, Sn-Bi, Sn-In, Sn-Pb, Ni-Sn, etc.

[0037] (Light-emitting element) The light-emitting device includes one or more light-emitting elements 10. As the light-emitting element 10, for example, a semiconductor light-emitting element such as a light-emitting diode can be used. The light-emitting element 10 includes a semiconductor laminate 11 and a pair of positive and negative electrodes 12. The semiconductor laminate 11 includes, for example, an element substrate such as sapphire and a semiconductor layer formed thereon. Alternatively, the semiconductor laminate 11 can be composed of only a semiconductor layer without an element substrate. The planar shape of the light-emitting element 10 can be a polygon such as a triangle, a quadrilateral, or a hexagon. The size of the light-emitting element 10 can be, for example, 100 μm or more and 3000 μm or less on one side in a plan view. Specifically, it can be a square with one side being about 600 μm, about 1000 μm, about 1400 μm, about 1700 μm, etc. Also, the light-emitting element 10 may be a rectangle having a long side and a short side in a plan view. For example, it can have a size of 1100 μm × 200 μm. When a plurality of light-emitting elements 10 are provided, the sizes, emission wavelengths, compositions, etc. of the respective light-emitting elements 10 may be the same, or some or all of them may be different. Also, all of the plurality of light-emitting elements 10 can be connected in series or in parallel, and can be connected such that series and parallel are mixed.

[0038] The semiconductor laminate 11 includes an n-type semiconductor layer and a p-type semiconductor layer, and a light-emitting layer sandwiched therebetween. Such a semiconductor laminate including a light-emitting layer is, for example, In x Al y Ga 1-x-y N (0 ≦ x, 0 ≦ y, x + y ≦ 1) can be included.

[0039] The semiconductor laminate 11 may have a structure including one or more light-emitting layers between an n-type semiconductor layer and a p-type semiconductor layer, or may have a structure in which a structure including an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer in this order is repeated a plurality of times. When the semiconductor laminate 11 includes a plurality of light-emitting layers, it may include light-emitting layers having different emission peak wavelengths, or may include light-emitting layers having the same emission peak wavelength. Note that the same emission peak wavelength includes cases where there is a variation of about several nm. The combination of emission peak wavelengths between the plurality of light-emitting layers can be appropriately selected. For example, when the semiconductor laminate includes two light-emitting layers, the light-emitting layers can be selected in combinations such as blue light and blue light, green light and green light, red light and red light, ultraviolet light and ultraviolet light, blue light and green light, blue light and red light, or green light and red light.

[0040] The light-emitting element includes at least a pair of electrodes on the lower surface side of the semiconductor laminate. In other words, one light-emitting element includes at least one positive electrode and at least one negative electrode as electrodes. In the light-emitting device 100A shown in FIG. 1A, one positive electrode and one negative electrode are respectively arranged for the light-emitting element 10. The positive electrode and the negative electrode each have a rectangular shape in plan view. Thus, when there is one positive electrode and one negative electrode, their respective sizes can be increased. Thereby, the contact area with the solder 30 can be increased, and the heat dissipation property can be improved.

[0041] At the upper end C11 of the first concave surface C1 of the conductive member 20, that is, at the corner (edge) located between the upper surface 20U and the side surface 20S, stress is likely to occur due to the difference in the coefficient of thermal expansion between the light-emitting element 10 and the conductive member 20. Therefore, the electrode 12 in the portion overlapping the edge of the conductive member 20 in plan view can be divided. For example, the electrodes 12 shown in FIG. 1A are each rectangular, and the portion continuous from one end to the other end of the electrode 12 overlaps the edge. On the other hand, the shape can be such that it is recessed inward from the long side of the electrode 12 in plan view so that the electrode 12 is not located in the portion overlapping the edge.

[0042] Alternatively, like the light-emitting device 100B shown in FIG. 1C, it may be provided with two positive electrodes and two negative electrodes. In this case, the planar shapes of the positive electrode and the negative electrode are each a square. By providing two or more of each of the positive electrode and the negative electrode in this way, the solder 30 is also divided into the number corresponding to each electrode 12. That is, in the example shown in FIG. 1C, four solders 30 are arranged. By using a plurality of solders 30 in this way, it is possible to reduce the breakage of the light-emitting element 10 or the occurrence of cracks in the solder 30. When there are a plurality of positive electrodes and negative electrodes, it is preferably arranged so as to be divided at a portion overlapping the edge in a plan view.

[0043] As the electrode 12 of the light-emitting element 10, an electrically conductive material can be used, and for example, it can be made of gold, silver, copper, platinum, iron, nickel, or an alloy thereof. The electrode 12 can include an ohmic electrode in contact with the lower surface of the semiconductor laminate 11 and a pad electrode connected to the ohmic electrode and connected to the outside. The thickness of the electrode can be, for example, 0.5 μm or more and 50 μm or less, more preferably 5 μm or more and 20 μm or less.

[0044] (Light-transmissive member) The light-transmissive member 40 is a light-transmissive member arranged to cover the upper surface of the semiconductor laminate 11 of the light-emitting element 10. The light emitted from the light-emitting element 10 is emitted to the outside through the light-transmissive member 40. In the light-emitting device 100 shown in FIG. 1B or the like, light is emitted to the outside from the upper surface of the light-transmissive member 40. As the light-transmissive member 40, a resin member, an inorganic member, glass, or a combination thereof can be used. The light-transmissive member 40 preferably has a light transmittance of 60% or more, more preferably 70% or more, and still more preferably 80% or more for light having a peak wavelength of the light emitted from the light-emitting element 10.

[0045] As the resin member, the light-transmitting member 40 can be made of a thermosetting resin such as silicone resin, silicone-modified resin, epoxy resin, or phenolic resin, or a thermoplastic resin such as polycarbonate resin, acrylic resin, methylpentene resin, or polynorbornene resin. In particular, a silicone resin with excellent light resistance and heat resistance is preferable. As the inorganic member, the light-transmitting member 40 can use silicon oxide, aluminum oxide, etc. As the glass, non-alkali glass, soda glass, soda-lime glass, borosilicate glass, aluminosilicate glass, quartz glass, low-alkali borosilicate glass, etc. can be used.

[0046] The light-transmitting member 40 may be composed of only these light-transmitting members, or may contain a phosphor that is excited by the light from the light-emitting element and converts it into light of a different wavelength, a light-scattering agent, etc. using these light-transmitting members as a base material.

[0047] As the phosphor, yttrium aluminum garnet-based phosphor, lutetium aluminum garnet-based phosphor, terbium aluminum garnet-based phosphor, CCA-based phosphor, SAE-based phosphor, chlorosilicate-based phosphor, silicate-based phosphor, oxynitride-based phosphor such as β-sialon-based phosphor or α-sialon-based phosphor, LSN-based phosphor, BSESN-based phosphor, SLA-based phosphor, nitride-based phosphor such as CASN-based phosphor or SCASN-based phosphor, KSF-based phosphor, KSAF-based phosphor or MGF-based phosphor, etc., quantum dots having a perovskite structure, II-VI group quantum dots, III-V group quantum dots, or quantum dots having a chalcopyrite structure can be used.

[0048] As the light-scattering agent, for example, particles such as titanium oxide, silicon oxide, aluminum oxide, zinc oxide, magnesium oxide, zirconium oxide, yttrium oxide, calcium fluoride, magnesium fluoride, niobium pentoxide, barium titanate, tantalum pentoxide, barium sulfate, or glass can be used.

[0049] The light-transmissive member 40 can be arranged on the light-emitting element 10 using a light-transmissive joining member 60 as shown in FIG. 1B, with a member pre-formed into a plate shape. In the example shown in FIG. 1B, the joining member 60 is thinly arranged between the light-emitting element 10 and the light-transmissive member 40 and covers the side surface of the light-emitting element 10. Also, as shown in FIG. 2, the light-emitting element 10 and the light-transmissive member 40 can be directly joined by a direct joining method or the like without using a joining member. Further, a liquid resin material can be arranged on the light-emitting element 10 and then cured to form the light-transmissive member 40. Alternatively, using a film-forming method such as sputtering, vapor deposition, or atomic layer deposition, a light-transmissive member 40 on a thin film can be arranged on the light-emitting element 10 as shown in FIG. 3.

[0050] As shown in FIG. 2, the light-transmissive member 40 can have the same area as the area of the light-emitting element 10, or as shown in FIG. 1B, can have an area larger than the area of the light-emitting element 10. Also, the light-transmissive member 40 preferably overlaps the entire surface of the light-emitting element 10 in plan view. For example, in plan view, a light-transmissive member 40 that overlaps the entire surface of the light-emitting element 10 and has a size larger than the light-emitting element 10 can be provided. The light-transmissive member 40 having a size larger than the light-emitting element 10 can continuously cover the light-emitting element 10 and the covering member 50 as shown in FIG. 1B or FIG. 3. The side surface of the light-transmissive member 40 may be covered by the covering member 50 as shown in FIG. 1B or FIG. 2, or may be exposed from the covering member 50 as shown in FIG. 3.

[0051] (Covering member) The covering member 50 covers the upper surface 20U of the first conductive member 21, the upper surface 20U of the second conductive member 22, and the side surface of the light-emitting element 10. The covering member 50 can cover in contact with the side surface of the light-emitting element 10. Alternatively, when a joining member 60 that joins the light-transmissive member 40 and the light-emitting element 10 covers a part of the side surface of the light-emitting element 10, the covering member 50 covers the side surface of the light-emitting element 10 via the joining member 60. Further, the covering member 50 also covers the lower surface of the semiconductor laminate 11 of the light-emitting element 10. Furthermore, the covering member 50 covers the solder 30 that covers the first concave surface C1 of the first conductive member 21 and the second conductive member 22, and at least a part of the second concave surface C2. The covering member 50 can be in contact with the lower surface of the light-transmissive member 40. Also, the covering member 50 can cover the side surface of the light-transmissive member 40.

[0052] The covering member 50 can be light-reflective, light-absorptive, or light-transmissive. As the base material of the covering member 50, a resin member can be used. As the resin member, thermosetting resins such as silicone resin, silicone-modified resin, epoxy resin, and phenolic resin, and thermoplastic resins such as polycarbonate resin, acrylic resin, methylpentene resin, and polynorbornene resin can be used. In particular, a silicone resin having excellent light resistance and heat resistance is preferable. When using a resin member, after joining the light-emitting element 10 and the conductive member 20 with solder 30, the covering member 50 can be formed by compression molding or transfer molding. In that case, it may be formed using a resin member melted in advance, or a powdery resin member may be arranged to cover the light-emitting element 10 and the conductive member 20, etc., and then formed by compression molding.

[0053] The covering member 50 can contain a light-reflective substance such as titanium oxide and zinc oxide. Alternatively, the covering member 50 can contain a light-absorptive substance such as carbon black and titanium black. The covering member 50 may contain both a light-reflective substance and a light-absorptive substance. In that case, both a light-reflective substance and a light-absorptive substance can be contained in one base material. Alternatively, the covering member 50 can be provided with a light-reflective first covering member in contact with the light-emitting element 10 and a light-absorptive second covering member outside the first covering member.

[0054] Further, the coating member 50 may be made of an inorganic material containing, for example, boron nitride or alkali metal silicate. In this case, it can further contain titanium oxide or zirconium oxide.

[0055] Also, the coating member 50 may include both a resin member and an inorganic material.

[0056] When the coating member 50 is light-reflective, the reflectance with respect to the light at the emission peak wavelength of the light emitted from the light-emitting element 10 is preferably 70% or more, more preferably 80% or more, and still more preferably 90% or more.

[0057] (Protective element) The light-emitting device 400 can include a protective element. For example, the light-emitting device 400A shown in FIGS. 4A to 4C includes a protective element 70 disposed so as to straddle the upper surface of the first conductive member 21 and the second conductive member 22. The protective element 70 includes an element portion and a pair of positive and negative electrodes disposed on the lower surface of the element portion, and is connected in parallel with the light-emitting element 10. In the case of a protective element 70 having a polarity such as a Zener diode, it is connected in the reverse direction to the light-emitting element 10. In the case of a protective element 70 having no polarity such as a varistor, it is connected to the light-emitting element 10 in the forward or reverse direction.

[0058] The light-emitting devices 400 shown in FIGS. 4D to 4F each include two light-emitting elements 10. The light-emitting device 400B shown in FIG. 4D includes two light-emitting elements 10 and two protective elements 70. The two pairs of conductive members 20 each include a first conductive member 21 and a second conductive member 22, and the light-emitting element 10 and the protective element 70 are disposed on the upper surfaces thereof. With such an arrangement, the two light-emitting elements 10 can be made to emit light simultaneously or separately.

[0059] The light-emitting device 400C shown in FIG. 4E includes two light-emitting elements 10 and two protection elements 70. The conductive member 20 includes two first conductive members 21 and one second conductive member 22 sandwiched therebetween. One light-emitting element 10 and one protection element 70 are joined to each of the two first conductive members 21 via solder. Two light-emitting elements 10 and two protection elements 70 are joined to the second conductive member 22 via solder. By adopting such an arrangement, the two light-emitting elements 10 can emit light simultaneously.

[0060] The light-emitting device 400D shown in FIG. 4F includes two light-emitting elements 10 and one protection element 70. The conductive member 20 includes two first conductive members 21 and one second conductive member 22. The two first conductive members 21 are longer in length than the second conductive member 22. The first conductive member 21 includes a portion sandwiching the second conductive member 22 and a portion extending in the lateral direction. The extended portions of the two first conductive members 21 are arranged to face each other, and one protection element 70 is arranged at that portion. That is, the protection element 70 is not joined to the second conductive member 22. Two light-emitting elements 10 are joined to the second conductive member 22 via solder, and one light-emitting element 10 is arranged on each of the two first conductive members 21. By adopting the conductive member 20 having such a shape, the mechanical strength of the light-emitting device 400C can be improved.

[0061] Here, an example in which the light-emitting element 10 and the protection element 70 are arranged on the same plane is shown. When a plurality of light-emitting elements 10 are provided in this way, the protection element 70 may not be provided. The position where the protection element 70 is placed is not limited to the upper surface 20U of the conductive member 20, and it may be arranged on the lower surface 20D side or the side surface 20S of the conductive member 20.

[0062] The role of the protection element 70 is to reduce the voltage load applied across the positive and negative electrodes 12 of the light-emitting element 10 by reducing the resistance of the parallel circuit formed by the protection element 70 and bypassing the current when an excessive voltage load is applied to the light-emitting device 400. For example, in the light-emitting device 400 shown in FIG. 4A and the like, the light-emitting element 10 and the protection element 70 are connected in parallel in the reverse direction, whereby a drive circuit including the light-emitting element 10 and a bypass circuit including the protection element 70 are formed. When the protection element 70 operates, the smaller the resistance of the bypass circuit, the smaller the current shunted to the light-emitting element 10 connected in parallel with the protection element 70 can be. For example, when the light-emitting device 400 is mounted on a wiring board, the resistance of the bypass circuit can be reduced by reducing the distance between the wiring of the wiring board and the protection element 70, that is, shortening the path of the bypass circuit. Thereby, the load on the light-emitting element 10 can be reduced, and the protection effect of the light-emitting element 10 can be further enhanced.

[0063] In the present embodiment, the protection element 70 and the conductive member 20 are joined by solder 30 in the same manner as the joining of the light-emitting element 10 and the conductive member 20. Since the solder 30 is thinner than the gold bump, the distance between the protection element 70 and the wiring of the wiring board can be made smaller when using the solder 30 compared to when using the gold bump. Therefore, the resistance of the bypass circuit can be made smaller compared to the case of using the gold bump. Further, the solder 30 for joining the protection element 70 is preferably arranged so as to continuously cover not only the upper surface 20U of the conductive member 20 but also a part of the side surface 20S.

[0064] The protection element 70 can be arranged on the same upper surface 20U as the upper surface 20U of the conductive member 20 on which the light-emitting element 10 is placed. Alternatively, the protection element 70 may be arranged in a recess R recessed from the upper surface 20U of the first conductive member 21 and the second conductive member 22 as shown in FIG. 4B. By arranging it in the recess R in this way, the path of the bypass circuit can be made shorter compared to the case where the protection element 70 is arranged on the upper surface 20U of the conductive member 20. Thereby, the resistance of the bypass circuit can be made smaller.

[0065] The recess R of the first conductive member 21 and the recess R of the second conductive member 22 are located between the side surface 20S and the upper surface 20U of the conductive member 20 facing each other. The protection element 70 is disposed on the bottom surfaces that respectively define the two recesses R via the solder 30. The solder 30 for joining the protection element 70 can be disposed to extend on the bottom surfaces that respectively define the recesses R of the first conductive member 21 and the second conductive member 22 and on the side surfaces continuous from the bottom surfaces. The distance between the first conductive member 21 and the second conductive member 22 is larger below the protection element 70 than the distance below the light-emitting element 10. Since the protection element 70 only needs to be electrically connected, the ratio of the size of the electrode of the protection element 70 to the size of the protection element 70 is small, and the amount of the solder 30 is also small. Therefore, as shown in FIG. 4B, the solder 30 located below the protection element 70 is preferably disposed so as to continuously cover a part of the side surface 20S from the upper surface 20U of the conductive member 20. The light-emitting element 10 and the protection element 70 may be disposed in either order.

[0066] The covering member 50 is disposed in the recess R so as to cover the protection element 70. By disposing the protection element 70 in the recess R, it is possible to reduce the absorption of the light from the light-emitting element 10 by the protection element 70. The recess R only needs to be sized such that the protection element 70 can be disposed therein. Also, the depth of the recess R can be made approximately the same as the thickness of the protection element 70.

[0067] Also, in the light-emitting device 500, the protection element 70 is disposed at a position overlapping the light-emitting element 10. For example, in the light-emitting device 500A shown in FIGS. 5A to 5C, the protection element 70 is disposed in a recess R recessed from the lower surface 20D of the conductive member 20. The recess R of the first conductive member 21 and the recess R of the second conductive member 22 are located on the side surface 20S of the conductive member 20 facing each other, and are each continuous with the lower surface 20D. The protection element 70 is disposed on the inner surfaces respectively defining the two recesses R via the solder 30. And a covering member 50 is disposed in the recess R. By disposing the protection element 70 at such a position, it is possible to reduce the absorption of the light from the light-emitting element 10 by the protection element 70. Note that when the protection element 70 is disposed on the lower surface 20D side of the conductive member 20, it may be disposed at a position not overlapping the light-emitting element 10 in plan view. In the example shown in FIG. 5A, the entire protection element 70 is disposed at a position overlapping the light-emitting element 10. In other words, the protection element 70 is disposed directly below the light-emitting element 10. Thereby, it is possible to reduce the increase in the size of the light-emitting device 500A in plan view. Also, the recess R capable of disposing the protection element 70 directly below the light-emitting element 10 can also be said to be a second concave surface C2 recessed from the side surface 20S of the conductive member 20. Further, the side surface 20S continuous from the upper surface 20U of the conductive member 20 has a first concave surface C1, a second concave surface C2 located therebelow, and a third concave surface continuous from the lower surface 20D further therebelow, and this third concave surface may be used as the recess R.

[0068] The protection element 70 is electrically connected to the conductive member 20 via the solder 30. For example, as shown in FIG. 5B, the solder 30 is disposed between the inner surface (the second concave surface C2) of the recess R recessed from the lower surface 20D of the conductive member 20 and the protection element 70. In this case, the solder 30 connecting the second conductive member 22 shown on the right side in FIG. 5B and the light-emitting element 10 is separated from the solder 30 connecting the protection element 70 and the second conductive member 22. That is, a part of the first concave surface C1 of the second conductive member 22 is exposed from the solder 30. Further, the solder 30 connecting the first conductive member 21 shown on the left side in FIG. 5B and the light-emitting element 10 is connected to the solder 30 connecting the protection element 70 and the first conductive member 21. That is, the first concave surface C of the first conductive member 21 is not exposed from the solder 30 at this position. FIG. 5B shows an example in which the solder 30 connected to the light-emitting element 10 and the solder 30 connected to the protection element 70 are separated on one hand and continuous on the other hand. However, the present invention is not limited to this, and both solders 30 may be separated or continuous.

[0069] When the light-emitting element 10 is provided on the upper surface 20U side of the conductive member 20 and the protection element 70 is provided on the lower surface 20D side in this way, the protection element 70 may be disposed after the light-emitting element 10 is disposed first, or the light-emitting element 10 may be disposed after the protection element 70 is disposed first.

[0070] In the light-emitting device 500B shown in FIG. 5D, a protection element 70 is disposed in a recess R recessed from the upper surface 20U of the conductive member 20. The recess R of the first conductive member 21 and the recess R of the second conductive member 22 are located on the side surface 20S of the conductive member 20 facing each other, and are each continuous with the upper surface 20U. The protection element 70 is disposed on the inner surface defining the two recesses R via a solder 30. By disposing the protection element 70 at such a position within the recess R, an increase in the size of the light-emitting device 500B in plan view can be reduced. The inner surface defining the recess R has a first concave surface C1 in the portion continuous from the upper surface 20U, where the solder 30 is disposed. In the example shown in FIG. 5D, the solder 30 connecting the conductive member 20 and the light-emitting element 10 and the solder 30 connecting the protection element 70 and the conductive member 20 are separated. The solder 30 connecting the conductive member 20 and the light-emitting element 10 and the solder 30 connecting the protection element 70 and the conductive member 20 may be continuous.

[0071] Further, the protection element 70 can be disposed so as to straddle the side surface 20S of the first conductive member 21 and the side surface 20S of the second conductive member 22, as in the light-emitting device 600 shown in FIGS. 6A to 6C. All of the protection elements 70 disposed at such a position may be covered by the covering member 50, or may be exposed from the covering member 50 as shown in FIG. 6B.

[0072] For example, as shown in FIG. 6C, the protection element 70 includes a rectangular parallelepiped element portion 71 and electrodes 72 provided at both ends thereof. The electrodes 72 cover all of the both end faces and cover a part of the side surfaces of the four faces continuous with each end face. In the example shown in FIG. 6A, one side surface of the electrode 72 is connected to the conductive member 20 via a solder 30. Not limited thereto, a solder 30 may be connected to the electrode 72 covering the end face of the protection element 70.

[0073] As shown in FIG. 6C, one surface of the electrode 72 of the protection element 70 is exposed from the covering member 50, and the element portion 71 is covered with the covering member 50. Not limited to this, both the element portion 71 and the electrode 72 may be exposed from the covering member 50. By thus exposing the electrode 72 of the protection element 70 from the covering member 50, the electrode 72 of the protection element 70 and the wiring of the wiring substrate can be electrically connected using solder or the like. That is, a voltage can be applied from the wiring substrate to the protection element 70 without passing through the conductive member 20. Thereby, the path of the bypass circuit can be made shorter.

[0074] When arranging the protection element 70 on the side surface 20S of the conductive member 20, for example, the lower surface 20D of the conductive member 20 is arranged to face the upper surface of an adhesive sheet or the like, and the protection element 70 is arranged so as to correspond to the side surface 20S of the conductive member 20. Thereafter, solder 30 is arranged between the side surface 20S of the conductive member 20 and the electrode 72 of the protection element 70 and hardened. Thereby, the protection element 70 can be connected to the side surface 20S of the conductive member 20.

[0075] Examples of the protection element 70 include a Zener diode, a varistor, and the like. The protection element 70 includes an element portion and a pair of electrodes arranged on the element portion. The element portion of the protection element 70 has a rectangular parallelepiped shape, and a pair of electrodes arranged on one surface of the element portion can be used. Alternatively, as in the protection element 70 shown in FIG. 6A or the like, a pair of electrodes 72 provided so as to cover a total of five surfaces including a rectangular parallelepiped element portion 71, two end faces including the short sides of the element portion 71, and a part of four side faces continuous from the end faces can be used. Examples of the protection element 70 having electrodes 72 of such a shape include a varistor. By using such a protection element 70, as shown in FIG. 6C, the electrode 72 of the protection element 70 can be exposed from the covering member 50 on the lower surface of the light-emitting device 600. The size of the protection element 70 is not particularly limited, and it may be smaller, larger, or of the same order of magnitude as the light-emitting element 10.

[0076] Aspects of the present invention are as follows, for example.

[0077] (Appendix 1) A first conductive member and a second conductive member each having an upper surface, a lower surface opposite to the upper surface, and a side surface between the upper surface and the lower surface; Solder disposed on the upper surface of the first conductive member and the upper surface of the second conductive member; A light-emitting element joined by the solder to the upper surface of the first conductive member and the upper surface of the second conductive member; A light-transmissive member disposed on the upper surface of the light-emitting element; A covering member covering the upper surface of the first conductive member, the upper surface of the second conductive member, and the side surface of the light-emitting element; Comprising; The side surface of the first conductive member includes a first concave surface continuous from the upper surface and a second concave surface located below the first concave surface; The solder continuously covers at least a part of the upper surface of the first conductive member and a part of the first concave surface; The covering member further covers the solder covering the first concave surface and at least a part of the second concave surface, a light-emitting device. (Appendix 2) The side surface of the second conductive member includes a first concave surface continuous from the upper surface and a second concave surface located below the first concave surface; The solder continuously covers at least a part of the upper surface of the second conductive member and a part of the first concave surface; The covering member further covers the solder covering the first concave surface of the second conductive member and at least a part of the second concave surface, the light-emitting device according to Appendix 1. (Appendix 3) The solder covers a part of the second concave surface of the first conductive member, the light-emitting device according to Appendix 1 or Appendix 2. (Appendix 4) The solder covers a part of the second concave surface of the second conductive member, the light-emitting device according to any one of Appendices 1 to 3. (Appendix 5) The thickness of the solder disposed on the upper surface of the conductive member is thicker than the thickness of the solder covering the first concave surface, the light-emitting device according to any one of Appendices 1 to 4. (Supplementary Note 6) The light-emitting device further includes a protection element, and is the light-emitting device according to any one of Supplementary Notes 1 to 5. (Supplementary Note 7) The first conductive member and the second conductive member each have a concave portion on the upper surface, and the protection element is placed on the bottom surface defining the concave portion. The light-emitting device is as described in Supplementary Note 6. (Supplementary Note 8) The protection element is arranged on the side surfaces of the first conductive member and the second conductive member. The light-emitting device is as described in Supplementary Note 6.

Explanation of Reference Numerals

[0078] 100, 200, 300, 400, 500, 600... Light-emitting device 10... Light-emitting element 11... Semiconductor laminate 12... Electrode 20... Conductive member (20U... Upper surface, 20D... Lower surface, 20S... Side surface, 20P... Processing portion) C1... First concave surface (C11... Upper end, C12... Lower end) C2... Second concave surface (C21... Upper end, C22... Lower end) 21... First conductive member 22... Second conductive member 30... Solder 40... Translucent member 50... Coating member 60... Joining member 70... Protection element (71... Element portion, 72... Electrode)

Claims

1. a first conductive member and a second conductive member each having a top surface, a bottom surface opposite the top surface, and a side surface between the top surface and the bottom surface; solder disposed on a top surface of the first conductive member and a top surface of the second conductive member; a light emitting element joined to an upper surface of the first conductive member and an upper surface of the second conductive member by the solder; a light-transmitting member disposed on an upper surface of the light-emitting element; a covering member that covers an upper surface of the first conductive member, an upper surface of the second conductive member, and a side surface of the light emitting element; Equipped with the side surface of the first conductive member includes a first concave surface continuing from the top surface and a second concave surface located below the first concave surface, the solder continuously covers the top surface of the first conductive member and at least a portion of the first concave surface; The covering member further covers the solder covering the first concave surface and at least a portion of the second concave surface.

2. the side surface of the second conductive member includes a first concave surface continuing from the top surface and a second concave surface located below the first concave surface, the solder continuously covers the top surface of the second conductive member and at least a portion of the first concave surface; The light emitting device according to claim 1 , wherein the covering member further covers the solder covering the first concave surface of the second conductive member and at least a portion of the second concave surface of the second conductive member.

3. The light emitting device according to claim 1 , wherein the solder covers a portion of the second concave surface of the first conductive member.

4. The light emitting device according to claim 1 , wherein the solder covers a portion of the second concave surface of the second conductive member.

5. The light emitting device according to claim 1 , wherein a thickness of the solder disposed on the upper surface of the conductive member is greater than a thickness of the solder covering the first concave surface.

6. The light emitting device according to claim 1 , further comprising a protective element.

7. The light emitting device according to claim 6 , wherein the first conductive member and the second conductive member each have a recess in the top surface, and the protective element is placed on a bottom surface that defines the recess.

8. The light emitting device according to claim 6 , wherein the protective element is disposed on a side surface of the first conductive member and the second conductive member.

Images