JP4829577B2 - Light emitting device - Google Patents

Description

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

  With the recent increase in output of LED chips, development of light-emitting devices that use LED chips for lighting purposes is underway (see, for example, Patent Document 1).

The light emitting device disclosed in the above-mentioned patent document is composed of a base material formed in a box shape with one surface opening by an inorganic material such as metal, and an airtight container forming material that is made of transparent glass or ceramic and closes the base material opening. A plurality of LED chips are distributed and mounted on the bottom wall of the base material, and light emitted from the LED chips is irradiated outside the hermetic container through the hermetic container forming material. .
JP 2004-119634 A

  In the light emitting device having the above configuration, since the LED chip is directly mounted on the bottom wall of the base material made of an inorganic material such as metal, an insulating base material is formed on the non-mounting portion of the LED chip on the bottom wall of the base material. When the lead pattern for electrically connecting the electrodes of each LED chip is formed on the surface of the insulating substrate, the light irradiated from the LED chip to the side (that is, the direction parallel to the surface of the bottom wall) In part, vignetting occurred on the insulating base material and the lead pattern, and there was a problem that the light extraction loss increased.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a light emitting device with reduced light extraction loss.

In order to achieve the above object, the invention of claim 1 is composed of an LED chip, a mounting substrate on which the LED chip is mounted, and a molded product of transparent resin, and surrounds the LED chip on the mounting surface side of the LED chip on the mounting substrate. Excited by the frame, a sealing part formed by filling the inside of the frame with a transparent resin material and sealing the LED chip, a lens arranged to overlap the sealing part, and irradiation light from the LED chip A dome-shaped molded product in which a phosphor that emits light of a color different from the emission color of the LED chip is molded together with a transparent material, and between the light emitting surface of the lens and the periphery of the frame, the light emitting surface and the inner surface And a color conversion member disposed on the mounting surface in a state where an air layer is provided so that the distance between the LED chip and the mounting plate is a metal plate on which the LED chip is mounted, and the LED chip on the metal plate. Laminated on non-mounting site And an insulating substrate having a lead pattern formed on the surface opposite to the metal plate and electrically connected to the electrode of the LED chip, and protrudes toward the LED chip on the mounting portion of the LED chip on the metal plate. In addition, a protruding portion on which the LED chip is mounted is provided on the tip surface, and the protruding amount of the protruding portion is set to be equal to or larger than the combined thickness of the insulating base material and the lead pattern.

  According to the present invention, a protruding portion is formed on the mounting portion of the LED chip in the metal plate, and the protruding amount of the protruding portion is determined by the thickness of the insulating base formed on the non-mounting portion of the LED chip, Since the thickness of the lead pattern formed on the surface of the insulating base material is set to be equal to or larger than the dimension, the light irradiated from the LED chip mounted on the projecting portion is laterally irradiated. There is no vignetting caused by light shielding by the lead pattern, and there is an effect that light extraction loss can be reduced.

  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; A lens 60 which is formed by molding a transparent material together with a lens 60 arranged in a superimposed manner and 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 that covers the lens 60 on the light emitting surface 60b side of 60 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. Has a 0 and. The light-emitting device 1 is mounted on the tool body 100 made of metal (for example, a metal having high thermal conductivity such as Al or Cu) via an insulating layer 90 made of, for example, a green sheet. The heat resistance to the main body 100 is reduced, and the heat dissipation is improved. Therefore, since the temperature rise of the junction temperature of the LED chip 10 can be suppressed and the input power can be increased, 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 that is laminated on the portion of the metal plate 21 where the LED chip 10 is not mounted. A pair of lead patterns 23 that are electrically connected to both electrodes (anode electrode and cathode electrode) (not shown) of the LED chip 10 are formed on the surface of the insulating substrate 22 opposite to the metal plate 21. Moreover, since the window hole 24 is provided in the site | part corresponding to the LED chip 10 in the insulating base material 22, and the LED chip 10 is mounted on the surface of the metal plate 21 exposed from the window hole 24, the LED chip 10 The generated heat can be directly transferred to the metal plate 21 without passing through the insulating base material 22. Here, although CuW is adopted as the material of the metal plate 21, any metal material having a relatively high thermal conductivity may be used, and not only CuW but also Al or the like may be adopted. 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 23a.

  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 formed of a GaN-based compound semiconductor material and having, for example, a double hetero structure is formed on the main surface side of the conductive substrate 11 by an epitaxial growth method (for example, MOVPE method). ), 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, a projecting portion 21a that protrudes toward the LED chip 10 is provided on the mounting portion of the LED chip 10 on the metal plate 21, that is, the portion of the metal plate 21 exposed from the window hole 24 of the insulating base material 22. 21 is formed integrally. The planar shape of the protruding portion 21a is formed in a rectangular shape having a size larger than the chip size of the LED chip 10, and the LED chip 10 is mounted on the surface of the protruding portion 21a. Further, one end of a bonding wire 14 made of a thin metal wire (for example, a gold thin wire, an aluminum thin wire, etc.) is connected to the non-mounting portion of the LED chip 10 on the surface of the protruding portion 21a, and the other end of the bonding wire 14 is one side. Therefore, the cathode electrode of the LED chip 10 is electrically connected to one lead pattern 23 via the protruding portion 21 a and the bonding wire 14. The anode electrode of the LED chip 10 is electrically connected to the other lead pattern 23 through the bonding wire 14.

  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 light emitted from the side surface of the LED chip 10 propagates through the sealing portion 50 and the air layer 80 to reach the color conversion member 70 and does not excite the phosphor of the color conversion member 70 or collide with the phosphor. Or the color conversion member 70 is transmitted.

  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. 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 mounting substrate 20 using, for example, an adhesive (for example, a silicone resin, an epoxy resin, or the like) on the periphery of the opening.

  As described above, in the light emitting device 1 according to the present embodiment, the metal plate 21 is provided with the projecting portion 21a on the metal plate 21 where the LED chip 10 is mounted and protruding to the LED chip 10 side. 21, and the protruding amount of the protrusion 21 a is set to be equal to or larger than the combined thickness of the insulating base material 22 and the lead pattern 23. That is, a protruding portion 21 a is formed at the mounting portion of the LED chip 10 on the metal plate 21, and the amount of protrusion of the protruding portion 21 a is determined by the thickness of the insulating base material 22 formed at the non-mounting portion of the LED chip 10. Since the thickness of the lead pattern 23 formed on the surface of the insulating base material 22 is set to be equal to or larger than the dimension, the LED chip 10 mounted on the projecting portion 21a is lateral (the surface of the metal plate 21). The light irradiated in the direction parallel to the light is not shielded by the insulating base material 22 or the lead pattern 23, and vignetting does not occur, and the light extraction loss can be reduced.

  It should be noted that a wide variety of different embodiments can be configured without departing from the spirit and scope of the present invention, and the present invention is not limited to a specific embodiment.

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 1 Light-emitting device 10 LED chip 20 Mounting board 21 Metal plate 21a Protrusion part 22 Insulating base material 23 Lead pattern

Claims (1)

An LED chip, a mounting substrate on which the LED chip is mounted, a frame made of a transparent resin molded product and surrounding the LED chip on the mounting surface side of the LED chip on the mounting substrate, and a transparent resin material filled inside the frame A sealing portion that seals the LED chip formed, a lens that is placed on the sealing portion, and a light that is excited by irradiation light from the LED chip and has a color different from the emission color of the LED chip. A dome-shaped molded product in which a phosphor that emits light is molded together with a transparent material, and an air layer is provided between the light emitting surface of the lens and the periphery of the frame so that the distance between the light emitting surface and the inner surface is substantially constant. A color conversion member disposed on the mounting surface in a provided state, and the mounting substrate is stacked on a metal plate on which the LED chip is mounted, and on the non-mounting portion of the LED chip on the metal plate, opposite to the metal plate On the side surface It consists of an insulating base material on which a lead pattern electrically connected to the electrode of the ED chip is formed, and the LED chip is mounted on the tip surface of the metal plate protruding from the LED chip side on the mounting part of the LED chip. A light emitting device characterized in that a projecting part is provided, and the projecting amount of the projecting part is set to be equal to or larger than the combined thickness of the insulating base material and the lead pattern.

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