JP2007088085A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device capable of radiating white light by using a single LED chip. <P>SOLUTION: The light-emitting device includes an LED chip 10 for radiating blue light; a packaging substrate 20 where the LED chip 10 is packaged; a frame 40 for surrounding the LED chip 10 at the packaging surface side of the LED chip 10 in the packaging substrate 20; a sealing section 50 that is formed by filling a transparent resin material to the inside of the frame, seals the LED chip 10 and bonding wires 14, 14 connected to the LED chip, and is elastic; and a dome-like color conversion member 70 that is a molding in which a yellow phosphor (YAG) excited by light radiated from the LED chip 10 and radiating yellow broad light is formed with a transparent material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting device using an LED chip (light emitting diode chip).

Conventionally, there has been a light emitting device that emits white light using a plurality of LED chips having different emission colors (see, for example, Patent Document 1).
JP 2000-340840 A

  However, when a plurality of LED chips are used as in the above conventional example, the structure for efficiently radiating the heat generated by each LED chip is complicated, and it is difficult to reduce the size and cost.

  This invention is made | formed in view of the said situation, and is providing the light-emitting device which can radiate | emit white light using a single LED chip.

  To achieve the above object, the present invention comprises an LED chip that emits blue light, a mounting substrate on which the LED chip is mounted, and a transparent resin material that surrounds the LED chip on the mounting surface side of the LED chip on the mounting substrate. A frame, a sealing portion for sealing an LED chip and a bonding wire connected to the LED chip, which is formed by filling a transparent resin material inside the frame, and a lens disposed on the sealing portion. A molded product in which a yellow phosphor that emits yellow light when excited by light emitted from an LED chip is molded together with a transparent resin material, covers the lens on the light emitting surface side of the lens, and the light emitting surface and the frame. A dome-shaped color conversion member disposed in such a manner that an air layer is formed therebetween, and the yellow phosphor is made of yttrium, aluminum, and garnet phosphor (YAG). The features.

  According to the present invention, white light is obtained by mixing the blue light of the LED chip and the yellow light converted by the color conversion member. Therefore, white light can be emitted using a single LED chip that emits blue light. In addition, by using yttrium / aluminum / garnet phosphor (YAG) as the yellow phosphor, a light-emitting device with good luminous efficiency can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 is a cross-sectional view of the light emitting device of the present embodiment, FIG. 2 is an exploded perspective view, and FIG. 3 is a plan view.

  The light emitting device of this embodiment includes an LED chip 10, a mounting substrate 20 on which the LED chip 10 is mounted, a frame body 40 that surrounds the LED chip 10 on the mounting surface side of the LED chip 10 on the mounting substrate 20, and a frame body 40. The LED chip 10 and the bonding wires 14 and 14 connected to the LED chip 10 are sealed and elastically sealed, and the sealing part 50 is overlapped with the sealing part 50. A lens 60 and a molded product obtained by molding together with a transparent material a phosphor that emits light of a color different from the emission color of the LED chip 10 when excited by light emitted from the LED chip 10. A dome-shaped color conversion member 70 that covers the lens 60 on the light emitting surface 60b side and is disposed in such a manner that an air layer 80 is formed between the light emitting surface 60b and the frame body 40; It is provided.

  The mounting substrate 20 includes a flat, substantially rectangular plate-like metal plate 21 and a substantially rectangular flat plate-like insulating member 22 joined to the surface of the metal plate 21 (the upper surface in FIGS. 1 and 2). The insulating member 22 is made of, for example, a copper-clad laminate (so-called FR-4 substrate) having a general heat resistance using a flame-retardant glass cloth base epoxy resin, and a lead pattern 23 paired on the surface. , 23 are formed, and a substantially rectangular window hole 24 penetrating in the thickness direction is provided at the center. The metal plate 21 is formed in a substantially rectangular flat plate shape that is sufficiently thicker than the insulating member 22 by a metal material (Cu, Al, etc.) having a relatively high thermal conductivity. Here, in the window hole 24 of the insulating member 22, a submount member 30 described later is joined to the metal plate 21, and heat generated in the LED chip 10 is transferred to the metal plate 21 via the submount member 30. It is supposed to be. The metal plate 21 and the insulating member 22 are fixed by a fixing material 25 made of a sheet-like adhesive film having insulating properties. Each lead pattern 23 has an outer lead portion 23b that is not covered by the color conversion member 70.

  The LED chip 10 is a GaN-based blue LED chip that emits blue light, and is a conductive substrate made of an n-type SiC substrate that has a lattice constant and a crystal structure close to GaN as a crystal growth substrate and has conductivity compared to a sapphire substrate. The light-emitting portion 12 is formed of a GaN-based compound semiconductor material on the main surface side of the conductive substrate 11 and has a laminated structure portion having, for example, a double hetero structure. ), A cathode electrode (n electrode) which is a cathode side electrode (not shown) is formed on the back surface of the conductive substrate 11, and is shown on the surface of the light emitting unit 12 (the outermost surface on the main surface side of the conductive substrate 11). An anode electrode (p electrode) which is an electrode on the anode side that is not to be formed is formed. In short, the LED chip 10 has an anode electrode formed on one surface side and a cathode electrode formed on the other surface side. The cathode electrode and the anode electrode are composed of a laminated film of a Ni film and an Au film, but the material of the cathode electrode and the anode electrode is not particularly limited, and a material capable of obtaining good ohmic characteristics For example, Al or the like may be employed. In the present embodiment, the light emitting unit 12 of the LED chip 10 is mounted on the metal plate 21 so as to be on the side farther from the metal plate 21 than the conductive substrate 11. The conductive plate 11 may be mounted on the metal plate 21 so as to be closer to the metal plate 21 than the conductive substrate 11. In consideration of the light extraction efficiency, it is desirable to arrange the light emitting unit 12 on the side away from the metal plate 21, but in this embodiment, the conductive substrate 11 and the light emitting unit 12 have the same refractive index. Therefore, even if the light emitting unit 12 is disposed on the side close to the metal plate 21, the light extraction loss does not become too large.

  Further, the LED chip 10 is formed on the metal plate 21 in the shape of a rectangular plate having a size larger than the chip size of the LED chip 10, and the LED chip 10 is caused by the difference in linear expansion coefficient between the LED chip 10 and the metal plate 21. It is mounted via a submount member 30 that relieves stress acting on the chip 10. The submount member 30 has not only a function of relieving the stress, but also a heat conduction function of transferring heat generated in the LED chip 10 to a range wider than the chip size of the LED chip 10 on the metal plate 21. . In the present embodiment, AlN having a relatively high thermal conductivity and insulation is used as the material of the submount member 30, and the LED chip 10 has the cathode electrode on the LED chip 10 side of the submount member 30. It is electrically connected to one lead pattern 23 via a bonding wire 14 which is provided on the surface and connected to the cathode electrode (not shown) and a metal wire (for example, a gold wire, an aluminum wire, etc.). The anode electrode is electrically connected to the other lead pattern 23 via the bonding wire 14. The LED chip 10 and the submount member 30 are bonded using lead-free solder such as AuSn or SnAgCu.

  The material of the submount member 30 is not limited to AlN, and any material may be used as long as the linear expansion coefficient is relatively close to 6H—SiC that is the material of the conductive substrate 11 and the heat conductivity is relatively high. Si or the like may be employed.

  Although the silicone resin is used as the transparent resin material of the sealing portion 50 described above, not only the silicone resin but also an acrylic resin may be used.

  On the other hand, the frame 40 has a cylindrical shape and is formed of a transparent resin molded product, and a silicone resin is used as the transparent resin used in the molded product. In short, in the present embodiment, the frame body 40 is formed of a translucent material having a linear expansion coefficient equivalent to that of the transparent resin material of the sealing portion 50. Here, in this embodiment, after the frame body 40 is fixed to the metal substrate 20, the sealing resin 50 is formed by filling (potting) the transparent resin material inside the frame body 40 and thermosetting the same. Yes. In the case where an acrylic resin is used as the transparent resin material instead of the silicone resin, it is desirable that the frame body 40 be formed of a molded product of acrylic resin.

  The lens 60 includes a biconvex lens in which the light incident surface 60a and the light emitting surface 60b on the sealing portion 50 side are formed in a convex curved surface shape. Here, the lens 60 is formed of a molded product of silicone resin, and has the same refractive index as that of the transparent resin material. However, the lens 60 is not limited to a molded product of silicone resin. You may comprise by.

  By the way, the lens 60 has a light emitting surface 60b formed in a convex curved surface shape that does not totally reflect the light incident from the light incident surface 60a at the boundary between the light emitting surface 60b and the air layer 80 described above. Here, the lens 60 is formed such that the light emitting surface 60 b is formed by a part of a spherical surface, and the center of the spherical surface is positioned on the center line of the light emitting unit 12 along the thickness direction of the LED chip 10. Yes. Therefore, the light emitted from the surface of the LED chip 10 opposite to the metal substrate 20 side (in this embodiment, the surface of the light emitting unit 12) is totally reflected at the boundary between the light emitting surface 60b and the air layer 80. It becomes easy to reach the color conversion member 70 without increasing the total luminous flux. The light emitted from the side surface of the LED chip 10 propagates through the sealing portion 50, the frame body 40, and the air layer 80 to reach the color conversion member 70 to excite the phosphor of the color conversion member 70 or to the phosphor. Passes through the color conversion member 70 without colliding.

  The color conversion member 70 is a molded article in which a transparent material such as a silicone resin and a particulate yellow phosphor that emits broad yellow light when excited by the blue light emitted from the LED chip 10 are mixed. It is comprised by. Therefore, in the light emitting device of the present embodiment, the blue light emitted from the LED chip 10 and the light emitted from the yellow phosphor are emitted through the outer surface 70b of the color conversion member 70, and white light can be obtained. it can. Note that the transparent material used as the material of the color conversion member 70 is not limited to the silicone resin, and for example, an acrylic resin, an epoxy resin, glass, or the like may be employed. The yellow phosphor mixed with the transparent material used as the material of the color conversion member 70 is yttrium aluminum garnet phosphor (YAG), which is particularly excellent in terms of luminous efficiency among various phosphors.

  Here, the color conversion member 70 has a dome shape in which the inner surface 70a extends along the light emitting surface 60b of the lens 60 (that is, a part of a spherical surface having a larger diameter than the spherical surface corresponding to the light emitting surface 60b of the lens 60). Shape). Therefore, the distance between the light emitting surface 60b and the inner surface 70a of the color conversion member 70 in the normal direction is a substantially constant value regardless of the position of the light emitting surface 60b of the lens 60. In addition, the color conversion member 70 is shape | molded so that the thickness along a normal line direction may become uniform irrespective of a position. The color conversion member 70 may be bonded to the insulating member 22 at the periphery of the opening using, for example, an adhesive (for example, a silicone resin, an epoxy resin, or the like).

  By the way, when using the light-emitting device of this embodiment for the light source of a lighting fixture, it mounts in the instrument main body 100 made from metal (for example, metal with high heat conductivity, such as Al and Cu) via the insulating layer 90 which consists of a green sheet. Is done. The insulating layer 90 has a function of electrically insulating and thermally coupling both the mounting substrate 20 and the instrument main body 100. However, the insulating layer 90 is not limited to an unsintered ceramic body formed into a sheet shape such as a green sheet, and for example, a thermosetting fixing material (for example, an epoxy resin) may be used.

  As described above, in the light emitting device according to the present embodiment, white light is emitted by the color mixture of the blue light of the LED chip 10 and the yellow light converted by the color conversion member 70, so that a single LED chip 10 is used. Since white light can be emitted and yttrium aluminum garnet phosphor (YAG) is used as the yellow phosphor, the luminous efficiency can be improved. In the present embodiment, a blue LED chip whose emission color is blue is used as the LED chip 10 and a SiC substrate is used as the conductive substrate 11, but a GaN substrate is used instead of the SiC substrate. When a SiC substrate or a GaN substrate is used, the crystal growth substrate has a higher thermal conductivity than the case where a sapphire substrate, which is an insulator, is used as the crystal growth substrate. Resistance can be reduced.

It is sectional drawing which shows embodiment. It is an exploded perspective view same as the above. It is a top view same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 LED chip 20 Mounting board 21 Metal plate 22 Insulating member 23 Lead pattern 30 Submount member 40 Frame 50 Sealing part 60 Lens 70 Color conversion member

Claims (1)

  LED chip that emits blue light, a mounting substrate on which the LED chip is mounted, a frame made of a transparent resin material that surrounds the LED chip on the mounting surface side of the LED chip on the mounting substrate, and a transparent resin material on the inner side of the frame The LED chip and the bonding wire that is connected to the LED chip are sealed, a lens that is placed on the sealing part, and excited by light emitted from the LED chip. A molded product in which a yellow phosphor that emits yellow light is molded together with a transparent resin material. The lens is covered on the light exit surface side of the lens, and an air layer is formed between the light exit surface and the frame. And a dome-shaped color conversion member, wherein the yellow phosphor is made of yttrium, aluminum, and garnet phosphor (YAG).

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