JP4483772B2 - Light emitting device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a light emitting device using an LED chip (light emitting diode chip) and a method for manufacturing the same.

  Conventionally, an LED chip, a circuit board on which the LED chip is mounted, a metal (for example, aluminum) frame that surrounds the LED chip on the LED chip mounting surface side of the circuit board, and an inner side of the frame There has been proposed a light emitting device including a sealing portion made of a transparent resin (for example, epoxy resin, silicone resin, etc.) filled with an LED chip and sealed with a bonding wire connected to the LED chip (for example, a patent) References 1 and 2). Here, the frames described in Patent Documents 1 and 2 are formed in a shape in which the opening area gradually increases as the distance from the circuit board increases, and the inner side surface is a mirror surface, which is emitted from the LED chip. It also serves as a reflector that reflects light.

Further, in Patent Document 2, a blue phosphor that emits blue light is used as an LED chip, and a yellow phosphor that emits light when excited by light emitted from the blue LED chip on a transparent resin that seals the blue LED chip. There has been proposed a light emitting device capable of obtaining an emission spectrum of white light by dispersing.
JP 2001-85748 A JP 2001-148514 A

  By the way, in the above-described light emitting device, when an epoxy resin is used as a material for the sealing portion, when a heat cycle test (temperature cycle test) in which a low temperature period of −40 ° C. and a high temperature period of 80 ° C. are alternately performed is performed. When the temperature is high, the bonding wire may be disconnected due to thermal expansion of the conductor pattern of the mounting substrate made of the circuit board. Moreover, the thing using an epoxy resin as a material of a sealing part had the malfunction that a weather resistance was low compared with the thing using a silicone resin.

  On the other hand, in the light emitting device described above, in the case where a silicone resin is used as the material of the sealing portion, the sealing portion is gel-like and elastic, and the bonding wire is not heated at the high temperature of the heat cycle test. Although it is possible to prevent disconnection, the linear expansion coefficient of the silicone resin that is the material of the sealing portion is a value that is 10 times or more that of aluminum that is the material of the frame, and the linear expansion coefficient of both Due to the difference, there was a problem that voids were generated in the sealing portion at low temperatures in the heat cycle test.

  Further, in the above light emitting device, the inner surface of the frame body is used as a mirror surface so that light from the LED chip is efficiently extracted to the outside of the sealing portion. There was a problem that light loss sometimes occurred.

  Moreover, although the said patent document 2 has described the light-emitting device which made a part of sealing part which seals the LED chip and the bonding wire connected to the LED chip into the shape of a convex lens, Since the phosphor is dispersed in part or all, the concentration of the phosphor tends to vary depending on the position of the sealing portion, which causes color unevenness. Further, when the phosphor is dispersed throughout the sealing portion, there is a problem that the amount of the phosphor used is increased and the cost is increased. On the other hand, a configuration in which a dome-shaped color conversion member made of a molded product obtained by molding a phosphor together with a transparent material is arranged in such a manner that an air layer is formed between the sealing portion and the sealing portion has been proposed. However, depending on the shape of the sealing portion, the light output may be reduced due to total reflection at the interface between the sealing portion and the air layer.

  The present invention has been made in view of the above-mentioned reasons, and an object of the present invention is to provide a light emitting device capable of improving reliability, improving light output, and suppressing occurrence of color unevenness, and a method for manufacturing the same. Is to provide.

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, and an LED chip that is sealed inside the frame body. sealed and the sealing part is such Rigel like silicone resin from the sealing resin material, transparent phosphors that emit light of different colors from the LED chips and the emission color of being excited by the light emitted LED chip A molded product that is molded together with the material, and is provided with a dome-shaped color conversion member that is fixed to the mounting substrate so that the frame is accommodated between the mounting substrate and the frame is made of a transparent resin molded product. A transparent resin portion made of a transparent resin material not lower than the refractive index of the sealing portion and the refractive index of the frame is interposed between the conversion member and the sealing portion and the outer surface of the frame.

According to this invention, since the sealing portion is formed of the sealing resin material that is a gel-like silicone resin and the frame body is formed of a transparent resin molded product, the frame body is formed of a metal material as in the past. The difference in linear expansion coefficient between the frame and the sealing part can be reduced compared to the case where the sealing part has a low temperature, and the generation of voids in the sealing part at the low temperature of the heat cycle test can be suppressed. In addition, since it is possible to suppress the occurrence of light reflection loss in the frame, it is possible to improve the light output, and the color conversion member, the sealing portion, and the outer surface of the frame Since there is interposed a transparent resin portion made of a transparent resin material that does not fall below the refractive index of the sealing portion and the refractive index of the frame, compared to the case where an air layer is formed inside the color conversion member, Suppressing the decrease in light output caused by total light reflection In addition, the light output can be improved, and the color conversion member can be excited by the light emitted from the LED chip, and a phosphor that emits light of a color different from the emission color of the LED chip is molded with a transparent material. Therefore, the occurrence of uneven color can be suppressed.

According to a second aspect of the invention, in the invention of claim 1, wherein the mounting board has a front Symbol metal plate LED chip Ru it is mounted, and the metal plate side and the respective two electrodes of the LED chip to the opposite surface electric to consist with connected thereto a pair of the LED insulating substrate window hole to the site is stacked provided et Re said metal plate corresponding to the chip together with the lead patterns are provided, wherein the LED chip includes: the LED chip the submount member is a size than the chip size of the LED chip is larger the LED chip and the metal plate due to the linear expansion coefficient difference therebetween to relax the stress acting on the LED chip between the metal plate preparative is mounted on the metal plate through a planar sub-mount member for thermally bonded, the submount member, the surface of the sub-mount member side of the LED chip Wherein the thickness is set to be positioned away from the mounting board side of the metal plate than the edge of in the color conversion member.

  According to this invention, it is possible to prevent light emitted from the LED chip from being emitted sideways through the joint portion between the color conversion member and the mounting substrate.

  The invention of claim 3 is a method of manufacturing a light emitting device according to claim 1 or claim 2, wherein the LED chip is mounted on the mounting board, the LED chip and the bonding wire are connected, and then the LED chip on the mounting board. After the frame body is fixed to the mounting surface side, a sealing portion is formed by filling the inside of the frame body with a sealing resin material that seals the LED chip and the bonding wire and curing the transparent resin. A transparent resin part is formed by positioning a color conversion member in which a transparent resin material serving as a part is placed on the inside of the mounting substrate and curing the transparent resin material.

  According to the present invention, it is possible to provide a light emitting device that can improve reliability, improve light output, and suppress the occurrence of color unevenness.

  According to the first aspect of the invention, it is possible to improve the reliability, improve the light output, and suppress the occurrence of uneven color.

  According to the invention of claim 3, there is an effect that it is possible to provide a light emitting device capable of improving the reliability, improving the light output, and suppressing the occurrence of uneven color.

  Hereinafter, the light-emitting device of the present embodiment will be described with reference to FIGS.

The light emitting device 1 according to the present embodiment includes an LED chip 10, a mounting substrate 20 on which the LED chip 10 is mounted, a frame 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 the LED chip 10 and the sealing portion 50 is Rigel like silicone resin such that the bonding wires 14, 14 connected to the LED chip 10 from sealed encapsulation resin material inside the body 40, emitted from the LED chip 10 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 mounted in such a manner that the frame body 40 is housed between the mounting substrate 20. A dome-shaped color conversion member 70 fixed to the substrate 20, and the frame body 40 is made of a transparent resin molded product, and the color conversion member 70, the sealing portion 50, and the frame body 40 are Side are interposed a transparent resin portion 80 made of a transparent resin material not less than the refractive index of the refractive index and the frame body 40 of the sealing portion 50 between.

  The light emitting device 1 of the present embodiment is used as a light source of a lighting fixture, for example, and is made of a metal (for example, a metal having high thermal conductivity such as Al or Cu) through an insulating layer 90 made of, for example, a green sheet. Since the heat resistance from the LED chip 10 to the instrument body 100 can be reduced and the heat dissipation can be improved, and the temperature rise of the junction temperature of the LED chip 10 can be suppressed. The optical output can be increased and the optical output can be increased. Here, in the case of a lighting fixture, a plurality of light emitting devices 1 are mounted on the fixture body 100 so that a desired light output is obtained, and the plurality of light emitting devices 1 are connected in series or in parallel. That's fine.

  The mounting board 20 is provided with a metal plate 21 and a pair of lead patterns 23 and 23 electrically connected to both electrodes (not shown) of the LED chip 10 on the surface opposite to the metal plate 21 side. A window hole 24 is provided in a portion corresponding to the LED chip 10 in the insulating substrate 22, and heat generated in the LED chip 10 is generated. Heat can be transferred to the metal plate 21 without passing through the insulating substrate 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 the present embodiment, the metal plate 21 is made of a heat conductive material and constitutes a heat transfer plate on which the LED chip 10 is mounted. The metal plate 21 and the insulating substrate 22 are a bonding metal layer 25 made of a metal material (here, Cu) formed on the surface of the insulating substrate 22 facing the metal plate 21 (see FIGS. 1 and 5). It is fixed through. Each lead pattern 23 is composed of a laminated film of a Cu film, a Ni film, and an Ag film. On the surface side of the insulating substrate 22 opposite to the metal plate 21 side, a resist layer 26 (see FIGS. 1 and 5) made of a white resin is laminated so as to cover the lead patterns 23 and 23. The resist layer 26 is formed with a circular opening window 26a exposing the inner lead portions 23a, 23a of the lead patterns 23, 23 at the center, and the outer lead portions 23b of the lead patterns 23, 23 at the periphery. Circular opening windows 26b and 26b are formed to expose each of 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. 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. Electrically connected to one lead pattern 23 via a bonding wire 14 provided on the surface and connected to the cathode electrode (see FIG. 4) and 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. In the submount member 30, 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 is formed around the conductor 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.

  As described above, the frame body 40 is made of a molded product of transparent resin (for example, silicone resin), is formed in an annular shape, and the edge on the mounting substrate 20 side is made of an adhesive over the entire circumference. It is fixed to the mounting substrate 20 via the part 75. Note that the same material as that of the frame body 40 is preferably used as an adhesive for bonding the frame body 40 and the mounting substrate 20.

  The silicone resin is used as the sealing resin material of the sealing portion 50 described above, but is not limited to the silicone resin, and for example, an acrylic resin may be used.

  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 arranged such that the inner surface 70 a is formed by a part of a spherical surface, and the center of the spherical surface is located on the center line of the light emitting unit 12 along the thickness direction of the LED chip 10. Yes. In short, the color conversion member 70 is disposed so that the optical axis coincides with the LED chip 10. 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 joined to the mounting substrate 20 using, for example, an adhesive (for example, a silicone resin, an epoxy resin, or the like) at the periphery of the opening.

  The light emission surface of the transparent resin portion 80 is in close contact with the inner surface 70a of the color conversion member 70 over the entire area, and the portion formed across the frame body 40 and the sealing portion 50 has a convex lens shape. It has become. The transparent resin portion 80 is formed of a silicone resin, but is not limited to the silicone resin, and may be formed of a transparent resin material that does not fall below the refractive index of the sealing portion 50 and the refractive index of the frame body 40. In other words, the transparent resin portion 80 only needs to be formed of a transparent resin material having a refractive index equal to or higher than the refractive index of the sealing portion 50 and the refractive index of the frame body 40.

  By the way, in the light-emitting device 1 of this embodiment, the thickness dimension of the submount member 30 described above is such that the surface of the LED chip 10 on the submount member 30 side is a metal plate than the edge of the color conversion member 70 on the mounting substrate 20 side. The light emitted from the LED chip 10 to the side can be prevented from being emitted through the joint 75 between the color conversion member 70 and the mounting substrate 20 ( That is, it is possible to prevent the blue light emitted from the LED chip 10 from being emitted outside without passing through the color conversion member 70).

  In manufacturing the light emitting device 1 of the present embodiment, as shown in FIG. 6A, after mounting the LED chip 10 on the mounting substrate 20 and connecting the LED chip 10 and the bonding wires 14, 14, the mounting substrate is mounted. After the frame body 40 is fixed to the mounting surface side of the LED chip 10 in 20, the LED chip 10 and the bonding wires 14 and 14 are sealed inside the frame body 40 as shown in FIG. The sealing portion 50 is formed by filling and curing the resin material, and then, as shown in FIG. 6C, the color conversion member 70 in which the transparent resin material 80a to be the transparent resin portion 80 is placed inside. Then, the color conversion member 70 is positioned with respect to the mounting substrate 20 and the transparent resin material 80a is cured to form the transparent resin portion 80. According to such a manufacturing method, it is difficult for voids to be generated in the sealing portion 50 during the manufacturing process, the reliability can be improved, the light output can be improved, and the occurrence of color unevenness can be suppressed. A device 1 can be provided.

In the light emitting device 1 of the present embodiment described above, the sealing portion 50 is formed of a sealing resin material that is a gel-like silicone resin, and the frame body 40 is formed of a transparent resin molded product. Compared with the case where the frame is made of a metal material, the difference in linear expansion coefficient between the frame 40 and the sealing portion 50 can be reduced, and voids are generated in the sealing portion at a low temperature in the heat cycle test. Therefore, it is possible to improve reliability, and it is possible to suppress the occurrence of light reflection loss in the frame body 40, so that the light output can be improved. Further, a transparent resin portion 80 made of a transparent resin material that does not fall below the refractive index of the sealing portion 50 and the refractive index of the frame body 40 is interposed between the color conversion member 70 and the outer surface of the sealing portion 50 and the frame body 40. Therefore, compared with the case where an air layer is formed inside the color conversion member 70, it is possible to suppress a decrease in light output due to total reflection of light and to improve light output. Further, since the color conversion member 70 is formed of 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 the light emitted from the LED chip 10, color unevenness Can be suppressed.

  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. Further, when the difference in linear expansion coefficient between the LED chip 10 and the mounting substrate 20 is relatively small, the submount member 30 described in the above embodiment is not necessarily provided. Further, the mounting substrate 20 may employ a structure other than the structure described in the above embodiment.

It is a schematic sectional drawing of the light-emitting device of embodiment. It is a general | schematic disassembled perspective view in which the light emitting device same as the above was partially broken. It is a principal part schematic plan view of a light-emitting device same as the above. It is a schematic perspective view of the submount member in a light emitting device same as the above. The insulating board | substrate in a light-emitting device same as the above is shown, (a) is a schematic plan view, (b) is a schematic cross-sectional view taken along the line ABCD of (a), and (c) is a schematic bottom view partially broken. is there. It is explanatory drawing of the manufacturing method of a light-emitting device same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting device 10 LED chip 14 Bonding wire 20 Mounting board 21 Metal plate 22 Insulating board 23 Lead pattern 26 Resist layer 30 Submount member 40 Frame 50 Sealing part 70 Color conversion member 80 Transparent resin part

Claims (3)

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 sealing resin material that seals the LED chip inside the frame body a sealing portion which is Rigel like silicone resin, a molded article obtained by molding with a transparent material phosphors that emit light of different colors from the LED chips and the emission color of being excited by the light emitted LED chip A dome-shaped color conversion member fixed to the mounting substrate so as to store the frame between the mounting substrate and the mounting substrate, and the frame is formed of a transparent resin molded product. A light-emitting device comprising a transparent resin portion made of a transparent resin material that does not fall below the refractive index of the sealing portion and the refractive index of the frame body between the outer surface of the frame body. The mounting board, a front Symbol metal plate LED chip Ru is mounted, said a pair of lead patterns connected opposite the LED chip both electrodes respectively electrically on the surface is provided with the metal plate side window holes at positions corresponding to the LED chips Re et provided consists of a is an insulating substrate laminated on the metal plate, wherein the LED chip, the linear expansion coefficient difference therebetween between said metal plate and the LED chip through the flat plate-like submount member to the submount a member in size than the chip size of the LED chip and increase the LED chip and the metal plate is thermally coupled to relax the stress due to acting on said LED chip It is mounted on the metal plate, the sub-mount member, the end surface of the sub-mount member side of the LED chip of the mounting substrate side in the color converting member The light-emitting device according to claim 1, wherein the thickness is set to be positioned at a distance from the metal plate than.   3. The method of manufacturing a light emitting device according to claim 1, wherein after mounting the LED chip on the mounting substrate and connecting the LED chip and the bonding wire, the frame body is mounted on the mounting surface side of the LED chip on the mounting substrate. Then, a sealing part is formed by filling the inside of the frame with a sealing resin material that seals the LED chip and the bonding wire, and then curing, and then a transparent resin material that becomes a transparent resin part is formed. A method for manufacturing a light emitting device, comprising: forming a transparent resin portion by positioning a color conversion member placed inside with respect to a mounting substrate and curing a transparent resin material.

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