JP2007088097A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device that combines an LED chip with a phosphor for irradiating light having a color differing from the luminescent color of an LED chip, and further gives directivity to the irradiated light. <P>SOLUTION: A reflection section 75 is formed in a cylindrical body shape spreading out toward the side of a lens 60. The inner surface is composed of a reflector 75c made of metal, ceramic, or the like. Light irradiated from the side of the LED chip 10 is propagated at a sealing section 50 for reaching the reflector 75c, and is reflected in the direction of the lens 60, and passes through the lens 60 and a color conversion member 70 before being output to the outside. <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 is a light emitting element in which an LED chip is mounted on a mounting substrate, and a wavelength conversion material that emits light of a color different from the emission color of the LED chip when excited by the light emitted from the LED chip and the LED chip. A technique for obtaining mixed color light having a hue different from the emission color of the LED chip including white is disclosed by combining the above phosphors (fluorescent pigments, fluorescent dyes, etc.). (For example, see Patent Document 1)
JP-A-2005-244076

  However, the light emitted from the LED chip simply passes through a color conversion member formed of a phosphor together with a transparent material and is output to the outside, and the emitted light has not been given directivity.

  The present invention has been made in view of the above-mentioned reasons, and an object of the present invention is to emit light of a color different from the emission color of the LED chip by combining the LED chip and the phosphor, and further to the emitted light. It is an object to provide a light-emitting device having the characteristics.

  The invention of claim 1 includes an LED chip, a mounting board on which the LED chip is mounted, a frame body that surrounds the LED chip on the mounting surface side of the LED chip on the mounting board, and a transparent resin material that is filled inside the frame body The LED chip and the pair of bonding wires electrically connected to the LED chip are sealed and elastically sealed, a lens placed on the sealed part, and a mounting board A reflective portion that is formed in a cylindrical body that surrounds at least the frame on the mounting surface side and is disposed so that one opening faces the mounting surface and reflects light emitted from the LED chip on the inner surface of the cylindrical body A phosphor that is excited by light emitted from the LED chip and emits light of a color different from the emission color of the LED chip together with a transparent material, and the other of the reflecting portions. Further comprising a dome-shaped color conversion member disposed in the form of an air layer is formed between the light exit surface of the lens cover the lens with Kutsugae設 the opening characterized.

  According to this invention, the light radiated from the side surface of the LED chip is also reflected by the reflecting portion, passes through the lens and the color conversion member, and is output to the outside. The light radiated from the LED chip is stronger than before. Has directivity. In addition, since there is no need for the color conversion member to be in close contact with the lens, it is possible to suppress a decrease in yield due to the dimensional accuracy and positioning accuracy of the color conversion member, and to occur in the color conversion member when an external force acts on the color conversion member. The advantage that the transmitted stress can be suppressed from being transmitted to the LED chip and each bonding wire through the lens and the sealing portion, and is radiated from the LED chip and incident on the color conversion member through the sealing portion and the lens. Of the light scattered by the phosphor particles, the amount of light scattered to the lens side and transmitted through the lens can be reduced, improving the light extraction efficiency to the outside as a whole device, and moisture in the external atmosphere There is an advantage that it is difficult to reach the LED chip.

  As described above, in the present invention, in a light emitting device that combines an LED chip and a phosphor that emits light of a color different from the light emission color of the LED chip, the emitted light can have directivity. effective.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
Hereinafter, the light-emitting device of this embodiment will be described with reference to FIGS.

  The light emitting device 1 of the present 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. The LED 40 and the bonding wires 14 and 14 connected to the LED chip 10 are formed by filling a transparent resin material on the inside of the LED 40 and have an elastic sealing part 50; The lens 60 arranged in an overlapping manner and a cylindrical body surrounding the lens 60 and the frame body 40 on the mounting surface side of the LED chip 10 on the mounting substrate 20 are disposed so that one opening 75a faces the mounting surface. The light emitted from the LED chip 10 is reflected by the inner surface of the cylinder, and the light emitted from the LED chip 10 is excited by the light emitted from the LED chip 10 to emit light. A dome-shaped color conversion member 70 that covers a lens 60 that is a molded product obtained by molding a phosphor that emits light of a color different from a color together with a transparent material and covers the other opening 75b of the reflecting portion 75. ing. Here, the color conversion member 70 covers the light emitting surface 60b side of the lens 60 and forms an air layer 80 between the light emitting surface 60b. In addition, the light emitting device 1 is mounted on the LED main body 100 via an instrument body 100 made of metal (for example, metal having high thermal conductivity such as Al and Cu) via an insulating layer 90 made of a green sheet, for example. Since the heat resistance from 10 to the instrument body 100 can be reduced, the heat dissipation is improved, and the temperature rise of the junction temperature of the LED chip 10 can be suppressed, the input power can be increased and the light output can be increased. .

  The mounting substrate 20 includes a metal plate 21 on which the LED chip 10 is mounted, and an insulating base material 22 made of a glass epoxy substrate laminated on the metal plate 21, and the metal plate in the insulating base material 22. A pair of lead patterns 23 that are electrically connected to both electrodes (not shown) of the LED chip 10 are provided on the surface opposite to the 21 side, and a window is formed at a portion corresponding to the LED chip 10 in the insulating substrate 22. A hole 24 is provided so that heat generated in the LED chip 10 can be transferred to the metal plate 21 without passing through the insulating base material 22. Here, Cu is employed as the material of the metal plate 21, but any metal material having a relatively high thermal conductivity may be used, and not only Cu but Al or the like may be employed. In addition, the metal plate 21 and the insulating base material 22 are fixed by a fixing material 25 made of an insulating sheet-like adhesive film. Each lead pattern 23 is composed of a laminated film of a Ni film and an Au film, and a portion not covered with the color conversion member 70 is an outer lead portion 23b.

  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. An electrode pattern provided on the surface and electrically connected to one lead pattern 23 via a bonding wire 14 made of a metal wire (for example, a gold wire, an aluminum wire) connected to the cathode electrode, and the anode electrode It is electrically connected to the other lead pattern 23 through the bonding wire 14. The LED chip 10 and the submount member 30 may be bonded using, for example, solder such as SnPb, AuSn, SnAgCu, or silver paste, but may be bonded using lead-free solder such as AuSn, SnAgCu. It is preferable. In addition, the submount member 30 is formed with a reflective film (for example, a laminated film of a Ni film and an Ag film) that reflects light emitted from the LED chip 10 around the electrode pattern.

  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 mounting substrate 20, the sealing resin 50 is formed by filling (potting) the transparent resin material inside the frame body 40 and thermosetting the same. is there. 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 is composed of a biconvex lens in which each of the light incident surface 60a and the light emitting surface 60b on the sealing portion 50 side is formed in a convex curved surface shape. Here, the lens 60 is formed of a molded product of silicone resin, and the refractive index is the same as that of the sealing portion 50. However, the lens 60 is not limited to the molded product of silicone resin. You may comprise by the molded article of resin.

  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 disposed so that the optical axis of the lens 60 is positioned on the center line of the light emitting unit 12 along the thickness direction of the LED chip 10.

  The reflecting portion 75 has a cylindrical shape with the opening 75b side widened. The inner surface of the reflecting portion 75 includes a reflecting mirror 75c made of metal, ceramic, or the like, and the light emitted from the side surface of the LED chip 10 is sealed 50. , Reaches the reflecting mirror 75c, and reflects toward the lens 60.

  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 1 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 is obtained. Can do. 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. Further, the phosphor mixed with the transparent material used as the material of the color conversion member 70 is not limited to the yellow phosphor. For example, white light can be obtained by mixing a red phosphor and a green phosphor.

  Here, the color conversion member 70 has an inner surface 70 a formed in a shape along the light emitting surface 60 b of the lens 60. 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 reflection portion 75 with the periphery of the opening using, for example, an adhesive (for example, silicone resin, epoxy resin).

  In the light emitting device 1 of the present embodiment described above, the light emitted from the side surface of the LED chip 10 propagates through the sealing portion 50 to reach the reflecting mirror 75c and is reflected in the direction of the lens 60. The light radiated from the side surface is also output to the outside through the lens 60 and the color conversion member 70. As described above, the light emitted from the LED chip 10 has a stronger directivity than the conventional one due to the light distribution function of the reflection portion 75.

  Further, in the light emitting device 1 of the present embodiment, the color conversion member 70 may be disposed in a form in which an air layer 80 is formed between the light emitting surface 60 b of the lens 60 and the frame body 40. Since it is not necessary for the lens 60 and the frame 40 to be in close contact with each other, it is possible to suppress a decrease in yield due to the dimensional accuracy and positioning accuracy of the color conversion member 70. Further, in the light emitting device 1 of the present embodiment, since the assembly of the color conversion member 70 is the final process at the time of assembly, the color conversion member 70 in which the blending of the phosphor with respect to the transparent material is adjusted according to the emission wavelength of the LED chip 10. By using, color variations can be reduced.

  In the light emitting device of this embodiment, since the air layer 80 is formed between the color conversion member 70 and the lens 60 as described above, the color conversion member 70 is applied when an external force is applied to the color conversion member 70. And the stress generated in the color conversion member 70 due to the external force is transmitted to the LED chip 10 and the bonding wires 14 and 14 through the lens 60 and the sealing portion 50. Since the fluctuation of the light emission characteristics of the LED chip 10 due to the external force and the disconnection of the bonding wires 14 and 14 are less likely to occur, there is an advantage that the reliability is improved. In addition, since the air layer 80 is formed between the color conversion member 70 and the lens 60, there is an advantage that moisture in the external atmosphere hardly reaches the LED chip 10.

  In addition, since the air layer 80 is formed between the color conversion member 70 and the lens 60, the color conversion member 70 is emitted from the LED chip 10 and enters the color conversion member 70 through the sealing portion 50 and the lens 60. Among the light scattered by the yellow phosphor particles in 70, there is an advantage that the amount of light scattered to the lens 60 side and transmitted through the lens 60 can be reduced, and the light extraction efficiency to the outside as the entire apparatus can be improved. is there.

  By the way, in the above-described embodiment, a blue LED chip whose emission color is blue is adopted as the LED chip 10, and a SiC substrate is adopted as the conductive substrate 11, but a GaN substrate is used instead of the SiC substrate. In the case of using a SiC substrate or a GaN substrate, the crystal growth substrate has a higher thermal conductivity than the case of using a sapphire substrate as an insulator as the crystal growth substrate. Thermal resistance can be reduced. Further, the light emission color of the LED chip 10 is not limited to blue, and may be, for example, red or green. That is, the material of the light-emitting portion 12 of the LED chip 10 is not limited to the GaN-based compound semiconductor material, and a GaAs-based compound semiconductor material, a GaP-based compound semiconductor material, or the like may be employed according to the emission color of the LED chip 10. Further, the conductive substrate 11 is not limited to the SiC substrate, and may be appropriately selected from, for example, a GaAs substrate and a GsP substrate according to the material of the light emitting unit 12.

It is a schematic sectional drawing which shows embodiment. It is a general | schematic disassembled perspective view which showed the same and partially fractured | ruptured. It is a principal part schematic plan view which shows the same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 LED chip 20 Mounting board 30 Submount member 40 Frame 50 Sealing part 60 Lens 70 Color conversion member 75 Reflection part 75a, 75b Opening 75c Reflective mirror

Claims (1)

LED chip, mounting substrate on which LED chip is mounted, frame body surrounding LED chip on the mounting surface side of LED chip on the mounting substrate, and LED chip formed by filling transparent resin material inside the frame body And a pair of bonding wires electrically connected to the LED chip, and a sealing portion having elasticity and an elastic lens, a lens disposed on the sealing portion, and at least a frame on the mounting surface side of the mounting substrate A reflecting portion that is formed in a cylindrical body that surrounds the body and has one opening disposed so as to face the mounting surface and reflects light emitted from the LED chip on the inner surface of the cylindrical body; and radiation from the LED chip. 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 when excited by the emitted light, and is covered with the other opening of the reflecting portion. The light emitting device characterized in that it comprises a dome-shaped color conversion member disposed in the form of an air layer is formed between the light exit surface of the lens cover to FIG.

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