JP2007088072A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device for reducing variations in the color of generated light and reducing height by restraining height dimensions. <P>SOLUTION: The light-emitting device includes an LED chip 10; 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 packaging substrate 20; a sealing section 50 that is formed by filling a transparent silicon resin to the inside of the frame, seals the LED chip 10 and bonding wires 14, 14, and is elastic; a Fresnel lens 60 arranged while being overlapped to the sealing section 50; and a cylindrical color conversion member 70 that is a molding in which a phosphor excited by light radiated from the LED chip and radiates light with a color differing from the luminescent color of the LED chip is formed with a transparent material, covers the Fresnel lens at the side of a light emission surface 60b of the Fresnel lens 60, and is arranged while an air layer 80 is formed between the light emission surface and the frame 40. <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, as a light emitting device, a concave portion is provided in the approximate center of the mounting substrate, an LED chip is disposed in the approximate center of the bottom surface of the concave portion, and the concave portion is filled with a color conversion member containing a phosphor. There is one in which a convex lens is arranged as an optical member on the light extraction surface side of the light emitting device. (For example, see Patent Document 1)
Some optical members use Fresnel lenses. (For example, see Patent Document 2)
JP 2005-135983 A Japanese Unexamined Patent Publication No. 2004-158635 (paragraph number [0008], FIG. 1)

  However, when a convex lens is used as an optical member as in Patent Document 1, there is a problem that the height dimension of the light emitting device is increased.

  Also in Patent Document 2, color variation occurs in the generated light due to variations in the emission wavelength of the LED chip.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a light-emitting device that reduces the color variation of generated light and further reduces the height by suppressing the height dimension. .

  The invention of claim 1 includes an LED chip, a mounting substrate 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 substrate, and a transparent resin material that is filled inside the frame body An LED chip and a pair of bonding wires that are electrically connected to the LED chip and sealed with elasticity, a Fresnel lens disposed on the sealing part, and an LED chip A molded product obtained by molding together with a transparent material a phosphor that is excited by light emitted from the LED chip and emits light of a color different from that of the LED chip. A Fresnel lens and a frame are formed on the mounting surface side of the mounting substrate. And a color conversion member disposed in a form in which an air layer is formed between the light emitting surface of the covering Fresnel lens and the frame.

  According to this invention, since the assembly of the color conversion member is the final step during assembly, color variation is reduced by using a color conversion member in which the blending of the phosphor with the transparent material is adjusted according to the emission wavelength of the LED chip. can do. Furthermore, by using a Fresnel lens, the height dimension can be made smaller than that of a conventional convex lens, and the overall height of the apparatus can be reduced and the height can be reduced.

  As described above, according to the present invention, there is an effect that the variation in color of the generated light can be reduced, and the height can be reduced to reduce the height.

  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; A molded product in which a Fresnel lens 60 arranged in an overlapping manner and a phosphor that is excited by light emitted from the LED chip 10 and emits light of a color different from the emission color of the LED chip 10 are molded together with a transparent material. The Fresnel lens 60 is disposed on the light emitting surface 60b side so as to cover the Fresnel lens 60 and form an air layer 80 between the light emitting surface 60b and the frame body 40. Cylindrical and a color conversion member 70 that. 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 31 (see FIG. 4) provided on the surface and connected to the cathode electrode and electrically connected to one lead pattern 23 via a bonding wire 14 made of a fine metal wire (for example, a gold fine wire, an aluminum fine 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 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. Further, 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 31.

  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 Fresnel lens 60 is configured by forming the light incident surface 60a on the sealing portion 50 side in a flat shape and dividing the light emitting surface 60b facing the inner surface 70a of the color conversion member 70 into a plurality of concentric annular lenses. As a whole, it is formed in a substantially flat plate shape. Here, the Fresnel lens 60 is formed of a molded product of silicone resin and has the same refractive index as that of the sealing portion 50. However, the Fresnel lens 60 is not limited to a molded product of silicone resin, for example, Alternatively, it may be formed of an acrylic resin molded product.

  By the way, the Fresnel lens 60 is disposed so that the optical axis of the Fresnel lens 60 is located 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 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 is formed in a cylindrical body having one end opened, and the inner surface 70 a is formed in a planar shape along the light emitting surface 60 b of the Fresnel 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 Fresnel 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.

  In the light emitting device 1 of the present embodiment described above, by using the Fresnel lens 60, the height dimension can be reduced as compared with the conventional convex lens, and the overall height of the apparatus is reduced and the height is reduced. be able to.

  In the light emitting device 1 of the present embodiment, the LED chip 10 and the bonding wires 14 and 14 connected to the LED chip 10 are sealed and elastically formed by filling the frame body 40 with a transparent resin material. Since the frame body 40 is made of a transparent resin molded product, the linear expansion coefficient difference between the frame body 40 and the sealing section 50 is compared with the case where the frame body is formed of a metal material. Since it is possible to suppress the generation of voids in the sealing portion 50 at the low temperature of the heat cycle test, the reliability can be improved and the frame body 40 has a light reflection loss. Since generation | occurrence | production can be suppressed, the improvement of an optical output can be aimed at.

  Further, in the light emitting device 1 of the present embodiment, the color conversion member 70 may be disposed in such a manner that an air layer 80 is formed between the light emitting surface 60b of the Fresnel lens 60 and the frame body 40. Since 70 does not need to be in close contact with the Fresnel lens 60 and the frame body 40, 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 Fresnel lens 60 as described above, the color conversion member when an external force acts on the color conversion member 70. The possibility that 70 is deformed and abuts against Fresnel lens 60 is reduced, and the stress generated in color conversion member 70 by the external force is transmitted to LED chip 10 and bonding wires 14 and 14 through Fresnel lens 60 and sealing portion 50. Therefore, there is an advantage that the reliability is improved because the variation of the light emission characteristics of the LED chip 10 and the disconnection of the bonding wires 14 and 14 are less likely to occur due to the external force. In addition, since the air layer 80 is formed between the color conversion member 70 and the Fresnel lens 60, there is an advantage that moisture in the external atmosphere hardly reaches the LED chip 10.

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

  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. It is a schematic perspective view of the submount member in the same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 LED chip 14 Bonding wire 20 Mounting board 21 Metal plate 22 Insulating base material 23 Lead pattern 30 Submount member 40 Frame 50 Sealing part 60 Fresnel lens 60a Light incident surface 60b Light output surface 70 Color conversion member 80 Air layer

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 sealed by an elastic sealing portion, a Fresnel lens arranged over the sealing portion, and light emitted from the LED chip A light emitting surface of the Fresnel lens, which is 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, covering the Fresnel lens and the frame on the mounting surface side of the mounting substrate And a color conversion member disposed in such a manner that an air layer is formed between the light emitting device and the frame.

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