JP4765507B2 - Light emitting device - Google Patents

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)
As this type of light-emitting device, for example, a white light-emitting device (generally called a white LED) that obtains white light (white light emission spectrum) by combining an LED chip that emits blue light or ultraviolet light and a phosphor. As shown in FIG. 4, the LED chip 110 that emits blue light, the metal substrate 120 on which the LED chip 110 is mounted via the submount member 130, and the metal An aluminum frame 140 that surrounds the LED chip 110 on the mounting surface side of the LED chip 110 on the substrate 120, and an LED chip 110 filled inside the frame 140 and bonding wires 114 and 114 connected to the LED chip 110 are provided. From the sealed sealing part 150, the lens 160 arranged to overlap the sealing part 150, and the LED chip 110 And a dome-shaped color conversion member 170 that contains a yellow phosphor that is excited by emitted light and emits light and is fixed to the frame 140 so as to cover the lens 160, thereby obtaining an emission spectrum of white light. Light emitting devices have been proposed. The metal substrate 120 has conductor patterns 123 and 123 that are paired on an insulating layer 122 on a metal plate 121, and the conductor patterns 123 and 123 and the LED chip 110 are connected by bonding wires 114 and 114. .
JP 2003-243724 A

  However, in the conventional light emitting device shown in FIG. 4, light emission cannot be confirmed by being blocked by the frame 140 from the side surface direction of the LED chip 110.

  The present invention has been made in view of the above reasons, and its purpose is to combine a LED chip and a phosphor to emit light having a color different from the emission color of the LED chip, and also to emit light from the side surface. The object is to provide a light-emitting device that can be confirmed.

The invention of claim 1 includes an LED chip, a mounting substrate on which the LED chip is mounted, a frame formed of a light- transmitting material surrounding the LED chip on the mounting surface side of the LED chip on the mounting substrate, and a frame An LED chip and a pair of bonding wires that are electrically connected to the LED chip and sealed with a transparent resin material inside are sealed, and an elastic sealing portion is placed over the sealing portion. 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 by being excited by the light emitted from the LED chip and the LED on the mounting substrate A dome-shaped color conversion member standing on the mounting surface of the chip and covering the lens and the frame, and forming an air layer between the lens and the frame and the color conversion member; The inner surface of the conversion member is formed in a shape along the light output surface of the lens, and the distance between the light output surface and the inner surface of the color conversion member in the normal direction of the light output surface of the lens is configured to be a substantially constant value. The mounting substrate includes a submount member on which the LED chip is mounted and a metal plate on which the submount member is mounted. The submount member has a difference in linear expansion coefficient between the LED chip and the metal plate. In addition to alleviating the stress acting on the LED chip due to the reflection film that reflects the light emitted from the LED chip is formed , the light emitted from the side surface of the LED chip is the sealing portion, the frame, After propagating through the air layer, it is output to the outside through the side surface of the color conversion member .

  According to the present invention, the light emitted from the side surface of the LED chip propagates through the sealing portion and the frame, and then passes through the side surface of the color conversion member and is output to the outside. Light emission can also be confirmed from the side of the light emitting device.

  As described above, the present invention has an effect that light emission can be confirmed also from the side in a light-emitting device that combines an LED chip and a phosphor that emits light of a color different from that of the LED chip.

  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 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. 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 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. You may make it mount in the metal plate 21 so that it may become the side near the metal plate 21 rather than the electroconductive board | substrate 11. FIG. 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 an electrode pattern provided on the surface and connected to the cathode electrode and a bonding wire 14 made of a fine metal wire (for example, a gold fine wire, an aluminum fine wire, etc.). 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 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 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.

  Further, the color conversion member 70 has a side wall portion 70c extending from the tip having an inner surface 70a along the light emitting surface 60b of the lens 60 toward the mounting surface of the mounting substrate 20 on which the LED chip 10 is mounted. The peripheral edge of the opening on the side wall 70c side is bonded to the mounting substrate 20 by using, for example, an adhesive (for example, silicone resin, epoxy resin). Therefore, the light emitted from the side surface of the LED chip 10 propagates through the sealing portion 50 and the frame body 40, then passes through the side wall portion 70 c of the color conversion member 70, and is output to the outside. In addition, light emission can be confirmed from the side surface of the light emitting device 1.

  In the light emitting device 1 of the present embodiment described above, the color conversion member 70 may be disposed in such a manner that the air layer 80 is formed between the light emitting surface 60b of the lens 60 and the frame body 40. Since it is not necessary to make 70 closely adhere to the 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 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. It is a schematic sectional drawing which shows a prior art example.

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 body 50 Sealing part 60 Lens 70 Color conversion member 80 Air layer

Claims (1)

An LED chip, a mounting substrate on which the LED chip is mounted, a frame formed of a translucent material surrounding 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 An LED chip and a pair of bonding wires that are formed by filling and electrically connected to the LED chip are sealed and elastically sealed; a lens that is placed on the sealed part; and the LED 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 light emitted from the chip, and stands on the mounting surface of the LED chip on the mounting substrate. And a dome-shaped color conversion member that covers the lens and the frame,
An air layer is formed between the lens and the frame and the color conversion member, the inner surface of the color conversion member is formed in a shape along the light emission surface of the lens, and the light in the normal direction of the light emission surface of the lens The distance between the emission surface and the inner surface of the color conversion member is configured to be a substantially constant value,
The mounting substrate includes a submount member on which the LED chip is mounted and a metal plate on which the submount member is mounted, and the submount member has a difference in linear expansion coefficient between the LED chip and the metal plate. As a result, the stress acting on the LED chip is relaxed, and a reflection film that reflects the light emitted from the LED chip is formed .
The light emitted from the side surface of the LED chip propagates through the sealing portion, the frame, and the air layer, and then passes through the side surface of the color conversion member and is output to the outside .

Images