JP2007165937A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device capable of suppressing temperature rise of an LED chip and realizing high output of optical output. <P>SOLUTION: The device is provided with an LED chip 10; a chip mounting member 70 having a conductive plate (heat transmitting plate) 71 having the LED chip 10 mounted on one surface side, and conductor patterns 73, 73 provided on the one surface side of the conductive plate 71 via an insulating portion 72 and electrically connected to the LED chip 10; and a sheet-like jointing member 80, arranged on the other surface side of the conductive plate 71 to joint the conductive plate 71 to a tool body 90 as a metal member for holding the chip-mounting member 70. A resin sheet, containing a filling material made of a filler and having low viscosity, when heated as the jointing member 80, and the jointing member 80 has electric insulation and a function of making the conductive plate 71 thermally couple with the tool body 90. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting device.

  Conventionally, LED chips are combined with LED chips and phosphors (fluorescent pigments, fluorescent dyes, etc.) as wavelength conversion materials that are excited by light emitted from the LED chips and emit light of a different emission color from the LED chips. Research and development of light-emitting devices that emit light of a color different from the color of the light is being conducted in various places. 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. Has been commercialized.

  In addition, with the recent increase in output of white LEDs, research and development for expanding white LEDs into lighting applications has become active, but the above-mentioned white LEDs require a relatively large light output, such as general lighting. When a single white LED cannot be used to obtain a desired light output, an LED unit (light emitting device) in which a plurality of white LEDs are mounted on a single circuit board is formed. Generally, a desired light output is ensured as a whole (for example, Patent Document 1).

  Conventionally, in a light emitting device including an LED chip and a circuit board on which the LED chip is mounted, in order to increase the light output by suppressing the increase in the junction temperature of the LED chip and increasing the input power. A structure for efficiently radiating the heat generated in the light emitting part of the LED chip to the outside has been proposed (for example, see Patent Document 2).

In the light emitting device disclosed in Patent Document 2, a conductive pattern 203 is formed on a metal plate 201 via an insulating resin layer 202 as a circuit board 200 on which the LED chip 10 ′ is mounted, as shown in FIG. A metal substrate is used, and heat generated in each LED chip 10 ′ is transferred to the metal plate 201 via the heat transfer member 210. Here, each LED chip 10 ′ is a GaN-based blue LED chip formed on one surface side of a crystal growth substrate made of a sapphire substrate whose light-emitting portion made of a GaN-based compound semiconductor material is an insulator, and a circuit board The other surface of the crystal growth substrate is a light extraction surface.
JP 2003-59332 A JP 2003-168829 A (paragraph [0030] and FIG. 6)

  By the way, when the light emitting device having the configuration shown in FIG. 12 is used for a lighting fixture, the fixture main body holding the circuit board 200 on which the LED chip 10 ′ is mounted is made of metal, and the metal plate 201 in the circuit board 200 of the light emitting device. It is conceivable that the heat of the light-emitting device is more efficiently dissipated by thermally coupling the light source to the tool body, but in order to ensure lightning surge resistance, between the tool body and the metal plate 201 of the circuit board 200 It is necessary to interpose a rubber sheet-like heat-dissipating sheet such as Sarcon (registered trademark) as a sheet-like insulating layer, and an instrument that is a metal member that holds the light-emitting device from the light-emitting portion of each LED chip 10 ′ Each LED chip 10 is prevented so that the thermal resistance to the main body is increased and the junction temperature of each LED chip 10 'does not exceed the maximum junction temperature. Must limit the input power to the high power of the optical output is difficult.

  In addition, when the above-described heat dissipation sheet is interposed between the metal plate 201 and the instrument main body, due to insufficient adhesion between the metal plate 201 and the heat dissipation sheet, a gap is generated between the two and the thermal resistance increases. In addition, the thermal resistance to the instrument body varied for each light emitting device.

  In the light emitting device disclosed in Patent Document 2, heat generated in the light emitting portion of the LED chip 10 ′ is transferred to the metal plate 201 via the heat transfer member 210 smaller than the size of the LED chip 10 ′. The thermal resistance from the LED chip 10 ′ to the metal plate 201 is relatively large, and when the sapphire substrate that is a crystal growth substrate is mounted so as to be thermally coupled to the metal plate 201, the thermal resistance of the sapphire substrate becomes large. There was also a problem that it ended up.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a light emitting device capable of suppressing an increase in the temperature of an LED chip and increasing the light output.

  According to the first aspect of the present invention, an LED chip, a heat transfer plate made of a heat conductive material on which the LED chip is mounted on one surface side, and an LED chip and an electric circuit provided on the one surface side of the heat transfer plate via an insulating portion. In order to join the heat transfer plate to the chip mounting member having a conductive pattern to be connected to the metal and the metal member holding the chip mounting member, electrical insulation is provided on the other surface side of the heat transfer plate. And a sheet-like joining member that thermally couples the heat transfer plate and the metal member.

  According to this invention, in order to join the heat transfer plate to the metal member holding the chip mounting member, the heat transfer plate is disposed on the other surface side of the heat transfer plate and has an electrical insulation property. Since it has a sheet-like joining member that thermally couples the member, it is mounted on the chip from the light emitting part of the LED chip compared to the case where a rubber sheet-like heat dissipation sheet is interposed between the metal member The heat resistance up to the metal member holding the member can be reduced, heat dissipation can be improved, variation in thermal resistance can be reduced, and the temperature rise of the junction temperature of the LED chip can be suppressed, so that the input power can be increased and the light output can be increased. High output can be achieved. Further, when used with the same light output as before, there is an advantage that the junction temperature of the LED chip can be reduced and the life of the LED chip is prolonged as compared with the conventional one.

  According to a second aspect of the present invention, in the first aspect of the invention, the LED chip includes a light emitting portion formed of a GaN-based compound semiconductor material on a main surface side of a conductive substrate made of a SiC substrate or a GaN substrate. It is characterized by being.

  According to the present invention, the lattice constant of the crystal growth substrate of the LED chip can be brought close to the lattice constant of the GaN-based compound semiconductor material, and the crystal growth substrate has conductivity. An electrode can be formed. In addition, the heat transfer property of the crystal growth substrate is better than when a sapphire substrate is used as the crystal growth substrate, and the thermal resistance of the crystal growth substrate can be reduced, so that heat dissipation is improved.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the difference in linear expansion coefficient between the LED chip and the heat transfer plate is larger than the chip size of the LED chip and interposed between the LED chip and the heat transfer plate. And a submount member that relieves stress acting on the LED chip due to the above.

  According to the present invention, it is possible to prevent the LED chip from being damaged due to a difference in linear expansion coefficient between the conductive substrate of the LED chip and the heat transfer plate, thereby improving reliability. it can.

  A fourth aspect of the present invention is characterized in that, in the first to third aspects of the present invention, the joining member is made of a resin sheet containing a filler made of a filler and having a low viscosity when heated.

  According to the present invention, a gap is generated between the chip mounting member and the bonding member due to insufficient adhesion between the chip mounting member and the bonding member, and thermal resistance is increased. It is possible to prevent a thermal resistance from increasing due to a gap between the chip mounting member and the joining member due to aging.

  A fifth aspect of the present invention is characterized in that, in the first to fourth aspects of the present invention, the joining member is set to have a larger planar size than the heat transfer plate.

  According to this invention, the creeping distance between the heat transfer plate and the metal member can be increased compared to the case where the joining member and the heat transfer plate are formed in the same plane size. The lightning surge resistance when used as a light source for lighting equipment can be enhanced.

  In the invention of claim 1, the thermal resistance from the light emitting part of the LED chip to the metal member holding the chip mounting member can be reduced, the heat dissipation can be improved and the variation in thermal resistance can be reduced, and the temperature of the junction temperature of the LED chip. Since the increase can be suppressed, the input power can be increased and the optical output can be increased.

(Embodiment 1)
Hereinafter, the light-emitting device of this embodiment will be described with reference to FIGS.

  A light emitting device (LED chip unit) 1 according to this embodiment is used as a light source of a lighting fixture, and is formed into a rectangular plate-shaped LED chip 10 and a rectangular plate shape larger than the chip size of the LED chip 10. 10 is a rectangular plate-like conductive plate 71 mounted on one surface side, and a conductor pattern (lead pattern) provided on the one surface side of the conductive plate 71 via an insulating portion 72 and electrically connected to the LED chip 10. ) 73 and 73, and a submount member that is interposed between the conductive plate 71 and the LED chip 10 to relieve the stress acting on the LED chip 10 due to the difference in linear expansion coefficient between them. 30 and light emitted from the side surface of the LED chip 10 which is disposed so as to surround the LED chip 10 on one surface side of the chip mounting member 70 A reflector 50 that reflects the LED chip 10 forward (upward in FIG. 1), a protective cover 60 that is attached to the front surface of the reflector 50 so as to cover the LED chip 10, and a metal that holds the chip mounting member 70 In order to join the conductive plate 71 to the manufactured instrument main body 90, the conductive plate 71 is disposed on the other surface side of the conductive plate 71 and has electrical insulation, and the conductive plate 71 and the instrument main body 90 are thermally coupled. And a sheet-like joining member 80 to be provided. In this embodiment, the instrument main body 90 constitutes a metal member that holds the chip mounting member 70, but the metal member that holds the chip mounting member 70 may be other than the instrument main body 90. Moreover, what is necessary is just to employ | adopt materials with high heat conductivity, such as Al and Cu, as a material of a metal member. In the present embodiment, the chip mounting member 70, the reflector 50, and the protective cover 60 constitute a package of the LED chip 10. Further, in the present embodiment, the conductive plate 71 constitutes a heat transfer plate made of a heat conductive material on which the LED chip 10 is mounted on one surface side.

  The lighting fixture in the present embodiment is used as, for example, a spotlight, and the fixture main body with respect to an arm 112 whose one end is coupled to a rotary base 110 fixed on the support base 100 using a shaft screw 111. 90 are coupled using a coupling screw 113.

  In addition, as shown in FIGS. 3 and 4, the lighting fixture in the present embodiment has a bottomed cylindrical shape in which the entire surface of the fixture main body 90 is open, and a plurality of light emitting devices 1 are provided in the fixture main body 90. Is stored. Here, in the lighting fixture in the present embodiment, each light emitting device 1 is mounted on the bottom wall 90 a of the fixture body 90 via the joining member 80, and the opening portion of the fixture body 90 is closed by the front cover 91. The front cover 91 includes a translucent plate 91 a made of a disk-shaped glass plate and an annular window frame 91 b that holds the translucent plate 91 a, and the window frame 91 b is attached to the instrument main body 90. . The translucent plate 91a is not limited to a glass substrate, but may be formed of a translucent material, and controls the light distribution of light emitted from each light emitting device 1 to the translucent plate 91a. You may provide a lens integrally.

  The plurality of light emitting devices 1 housed in the instrument body 90 are connected in series by a plurality of lead wires 93 (see FIGS. 1 and 3), and lead wires at both ends of the series circuit of the plurality of light emitting devices 1. 93 is inserted into an insertion hole 90c provided in the bottom wall 90a of the instrument body 90, and power is supplied from a power supply circuit (not shown). As the power supply circuit, for example, a power supply circuit having a rectifier circuit composed of a diode bridge that rectifies and smoothes the AC output of an AC power supply such as a commercial power supply and a smoothing capacitor that smoothes the output of the rectifier circuit is employed. That's fine. In the present embodiment, the plurality of light emitting devices 1 in the instrument main body 90 are connected in series. However, the connection relationship between the plurality of light emitting devices 1 is not particularly limited. For example, the light emitting devices 1 are connected in parallel. Alternatively, a series connection and a parallel connection may be combined.

  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) (not shown) is formed on the back surface of the conductive substrate 11, and an anode electrode (p electrode) (not shown) is formed on the surface of the light emitting portion 12 (the outermost surface on the main surface side of the conductive substrate 11). ) 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.

  Here, in the LED chip 10, the anode electrode is electrically connected to one end portion (inner lead portion) of one conductor pattern 73 of the chip mounting member 70 via the bonding wire 14 (the bonding wire 14 on the left side in FIG. 1). The cathode electrode is electrically connected to one end portion (inner lead portion) of the other conductor pattern 73 of the chip mounting member 70 via the submant member 30 and the bonding wire 14 (the bonding wire 14 on the right side in FIG. 1). The other end portion of each conductor pattern 73 is electrically connected to the lead wire 93 via a joint portion 95 made of solder.

  As the material of the conductive plate 71, the chip mounting member 70 may be a conductive material having a relatively high thermal conductivity, such as Cu or phosphor bronze. For example, Cu may be adopted. Further, as a material of the insulating portion 72 of the chip mounting member 70, for example, a glass epoxy resin such as FR4, a polyimide resin, a resin having an insulating property such as a phenol resin may be employed. Here, in the chip mounting member 70, a window hole 75 exposing a part of one surface of the conductive plate 71 is formed in the central part of the insulating part 72, and the LED chip 10 is disposed inside the window hole 75. It is mounted on the conductive plate 71 via the submount member 30. Since the conductive plate 71 has only to have the same thickness as the lead frame, the thickness dimension should be smaller than the thickness dimension of the circuit board in the light emitting device disclosed in Patent Documents 1 and 2 above. Can do.

  In this embodiment, the LED chip 10 is mounted on the conductive plate 71 so that the light emitting part 12 of the LED chip 10 is farther from the conductive plate 71 than the conductive substrate 11. The conductive plate 71 may be mounted so that 12 is closer to the conductive plate 71 than the conductive substrate 11. Considering the light extraction efficiency, it is desirable to arrange the light emitting part 12 on the side away from the conductive plate 71. However, in this embodiment, the conductive substrate 11 and the light emitting part 12 have the same refractive index. Therefore, even if the light emitting unit 12 is arranged on the side close to the conductive plate 71, the light extraction loss does not become too large.

  In addition, the reflector 50 has a circular frame-like shape and is formed in a shape in which the opening area increases as the distance from the LED chip 10 increases in the thickness direction of the LED chip 10, and has a sheet shape having an insulating property. The chip mounting member 70 is fixed by a fixing material 55 made of an adhesive film.

  As a material of the reflector 50, a material (for example, Al) having a relatively high reflectance with respect to light emitted from the LED chip 10 (here, blue light) may be used. Note that a circular opening 55 a corresponding to the opening of the reflector 50 is formed in the fixing material 55. Moreover, it is desirable to pot a transparent sealing resin (for example, silicone resin) for sealing the LED chip 10 inside the reflector 50.

  The protective cover 60 has a dome-shaped cover portion 62 disposed so that its center is located on the center line along the thickness direction of the LED chip 10, and continuously protrudes sideways from the periphery of the opening of the cover portion 62. An annular positioning rib 61a is projected from the peripheral portion of the surface of the flange portion 61 on the reflector 50 side so that the flange portion 61 can be stably positioned with respect to the reflector 50. Yes. Note that the protective cover 60 may be bonded to the reflector 50 using, for example, an adhesive (for example, a silicone resin, an epoxy resin, or the like).

  In addition, the protective cover 60 is a mixture of a translucent material such as silicone and a particulate yellow phosphor that emits broad yellow light that is excited by the blue light emitted from the LED chip 10. It is composed of a molded product. Therefore, in the light emitting device 1 of this embodiment, the protective cover 60 is also excited by the light emitted from the LED chip 10 and also serves as a color conversion unit that emits light of a color different from the emission color of the LED chip 10. The light emitting device 1 as a whole constitutes a white LED that outputs white light composed of combined light of blue light emitted from the LED chip 10 and light emitted from the yellow phosphor. The translucent material used as the material of the protective cover 60 is not limited to silicone, and for example, an acrylic resin, an epoxy resin, glass, or the like may be employed. Further, the phosphor mixed with the translucent material used as the material of the protective cover 60 is not limited to the yellow phosphor, and for example, white light can be obtained by mixing a red phosphor and a green phosphor. Further, when the light emission color of the LED chip 10 is the same as the desired light emission color of the light emitting device 1, it is not necessary to mix the phosphor with the translucent material.

  By the way, in this embodiment, the blue LED chip whose emission color is blue is adopted as the LED chip 10 as described above, and the SiC substrate is adopted as the conductive substrate 11, but GaN is used instead of the SiC substrate. A substrate may be used. When a SiC substrate or a GaN substrate is used, as can be seen from Table 1 below, when a sapphire substrate that is an insulator is used as a substrate for crystal growth as in Patent Document 2 above. In comparison, the crystal growth substrate has a high thermal conductivity and a low thermal resistance. 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, as described above, the LED chip 10 is formed in a rectangular plate size larger than the chip size of the LED chip 10, and is caused by the difference in linear expansion coefficient between the LED chip 10 and the conductive plate 71. 10 is mounted on the conductive plate 71 through a submount member 30 that relieves stress acting on the substrate 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 in the conductive plate 71. The surface area of the conductive plate 71 on the LED chip 10 side is desirably sufficiently larger than the surface area of the LED chip on the chip mounting member 70 side. For example, in order to efficiently perform waste heat from the 0.3 to 1.0 mm square LED chip 10, the contact area between the conductive plate 71 and the bonding member 80 is increased and the heat of the LED chip 10 is increased. It is preferable to reduce the thermal resistance so as to conduct heat uniformly over a wide range. The surface area of the conductive plate 71 on the LED chip 10 side is 10 times the surface area of the LED chip 10 on the conductive plate 71 side. It is desirable to make it more than twice. Here, the submount member 30 only needs to have a function of relieving the stress, and the thickness dimension is made smaller than the thickness dimension of the circuit board in the light emitting device disclosed in Patent Documents 1 and 2 above. Therefore, the heat resistance can be reduced by adopting a material having a relatively large thermal conductivity.

  In this embodiment, CuW is used as the material of the submount member 30, and the LED chip 10 is electrically connected to one conductor pattern 73 via the bonding wire 14 in the LED chip 10 as described above. The cathode electrode is electrically connected to the other conductor pattern 73 via the submount member 30 and the bonding wire 14.

  The material of the submount member 30 is not limited to CuW. For example, as can be seen from Table 2 below, the material of the submount member 30 is a material whose linear expansion coefficient is relatively close to 6H—SiC which is the material of the conductive substrate 11 and whose thermal conductivity is relatively high. For example, W, AlN, composite SiC, Si, or the like may be employed. However, when an insulator such as AlN or composite SiC is adopted as the submount member 30, for example, an appropriate electrode pattern to be bonded to the cathode electrode is provided on the surface of the submount member 30 on the LED chip 10 side. The electrode pattern and the other conductor pattern 83 may be electrically connected via the bonding wire 14.

  Here, when the material of the conductive plate 71 is Cu, if CuW or W is adopted as the submount member 30, the submount member 30 and the conductive plate 71 can be directly joined. As shown in Table 3, it is possible to increase the bonding area between the submount member 30 and the conductive plate 71 as compared with the case where the submount member 30 and the conductive plate 71 are bonded using a brazing material. Thus, the thermal resistance of the joint between the conductive plate 30 and the conductive plate 71 can be reduced. The LED chip 10 and the submount member 30 may be bonded using lead-free solder such as AuSn or SnAgCu. However, when bonding using AuSn, the bonding surface of the submount member 30 is preliminarily formed on the bonding surface. Alternatively, a pretreatment for forming a metal layer made of Ag is necessary.

  Further, when W is used as the material of the submount member 30 and the submount member 30 and the conductive plate 71 are directly joined, as can be seen from Table 4 below, the submount member 30 and the conductive plate 71 are made of silver. Compared with the case where it joins using brazing, thermal conductivity becomes large and thermal resistance can be reduced. When the material of the conductive plate 71 is Cu and AlN, composite SiC, or the like is adopted as the material of the submount member 30, the conductive plate 71 and the submount member 30 are made of lead such as AuSn and SnAgCu. Bonding may be performed using free solder. However, when bonding using AuSn, a pretreatment for forming a metal layer made of Au or Ag in advance on the bonding surface of the conductive plate 71 is necessary.

  By the way, as described above, the light emitting device 1 of the present embodiment is disposed on the other surface side of the conductive plate 71 in order to join the conductive plate 71 to the metal instrument body 90 that holds the chip mounting member 70. It is provided with a sheet-like joining member 80 that is electrically insulated and that thermally couples the conductive plate 71 and the instrument body 90, and is joined to the instrument body 90 via the joining member 80. Has been. That is, in the lighting fixture in this embodiment, the sheet-like joining member 80 is interposed between the conductive plate 71 of the chip mounting member 70 of each light emitting device 1 and the fixture main body 90 that is a metal member. The member 80 has a function of electrically insulating and thermally coupling both the conductive plate 71 and the instrument main body 90.

  Here, when a conventional heat dissipation sheet is interposed between the conductive plate 71 and the instrument main body 90, a gap is generated between the two due to insufficient adhesion between the conductive plate 71 and the heat dissipation sheet. As a result, the thermal resistance increases or the thermal resistance up to the instrument body 90 varies for each light-emitting device 1.

On the other hand, in the light emitting device 1 of the present embodiment, the sheet-like bonding member 80 includes a resin sheet (for example, fused silica) containing a filler made of a filler such as silica or alumina and having a low viscosity when heated. Organic green sheet such as an epoxy resin sheet filled with a high degree of electrical conductivity), and has electrical insulation properties, high thermal conductivity, high fluidity during heating, and high adhesion to uneven surfaces. The plate 71 is joined to the metal instrument main body 90 via the joining member 80 (the joining member after the joining member 80 is interposed between the conductive plate 71 of the chip mounting member 70 and the instrument main body 90). 80 is heated to join the conductive plate 71 and the instrument main body 90) to prevent a gap from being generated between the joining member 80, the conductive plate 71, and the instrument main body 90. Thus, an increase in thermal resistance due to insufficient adhesion and the occurrence of variations can be prevented, and the LED chip 10 is mounted on the circuit board as in the prior art, and the sircon ( Compared to a case where a rubber sheet-like heat dissipation sheet such as a registered trademark is sandwiched, the thermal resistance from the LED chip 10 to the appliance main body 90 can be reduced, heat dissipation is improved, and variation in thermal resistance is small. Therefore, since 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. Regarding the bonding member 80, for example, when the effective contact area for heat transfer to the instrument body 90 is 25 mm ² and the thickness of the bonding member 80 is 0.1 mm, the thermal resistance of the bonding member 80 is 1K. In order to suppress to / W or less, it is necessary to satisfy the condition that the thermal conductivity of the bonding member 80 is 4 W / m · K or more. However, if an epoxy resin sheet highly filled with the above fused silica is used. This condition can also be satisfied.

  Note that the submount member 30 interposed between the LED chip 10 and the conductive plate 71 is not necessarily provided when the difference in linear expansion coefficient between the LED chip 10 and the conductive plate 71 is relatively small. In the case where the submount member 30 is not interposed between the LED chip 10 and the conductive plate 71, the distance between the LED chip 10 and the bottom wall 90a of the metal instrument body 90 is shortened. Since the thermal resistance from the light emitting part 12 of the LED chip 10 to the instrument main body 90 can be further reduced and the heat dissipation is further improved, the light output can be further increased.

(Embodiment 2)
Hereinafter, the light-emitting device of this embodiment will be described with reference to FIGS.

  The basic configuration of the light emitting device 1 of the present embodiment is substantially the same as that of the first embodiment, and is a dome-shaped optical member that controls the light distribution of the light emitted from the LED chip 10, and is between the chip mounting member 70. An optical member 160 made of a translucent material fixed to one surface side (the upper surface side in FIG. 5) of the chip mounting member 70 so as to accommodate the LED chip 10, and the optical member 160 and the chip mounting member 70 are surrounded. A sealing resin made of a sealing resin that seals the LED chip 10 and a plurality (four in this embodiment) of bonding wires 14 electrically connected to the LED chip 10 in the open space. Fluorescence which is excited by light emitted from the LED chip 10 and transmitted through the sealing part 150 and the optical member 160 and emits light of a color different from the emission color of the LED chip 10. A dome-like product formed with a light-transmitting material and disposed in such a manner that an air layer 180 is formed between the one surface side of the chip mounting member 70 and the light emitting surface 160b of the optical member 160. The color conversion member 170 is different. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  The chip mounting member 70 in this embodiment includes a rectangular plate-shaped conductive plate 71 on which the LED chip 10 is mounted via the submount member 30, and a polyolefin-based fixing sheet 79 on one surface side of the conductive plate 71. It is comprised with the wiring board 74 which consists of a flexible printed wiring board of the rectangular plate shape fixed via (refer FIG. 6). Here, the chip mounting member 70 is provided on one surface side of the conductive plate 71 on the wiring board 74 via an insulating portion 72 made of an insulating base material, and is electrically connected to the LED chip 10. A window hole 75 exposing a part of one surface of the conductive plate 71 is formed in the central portion of the insulating portion 72, and the LED chip 10 is disposed inside the window hole 75. It is mounted on the conductive plate 71 through 30. Note that a polyimide film is used as the insulating portion 72 of the wiring board 74, and each conductor pattern 73, 73 is formed of a laminated film of a Cu film, a Ni film, and an Au film.

  In addition, the wiring substrate 74 has a resist layer 76 made of a white resin that reflects light emitted from the LED chip 10 laminated on the surface side opposite to the conductive plate 71 side.

  In the present embodiment, AlN having a relatively high thermal conductivity and insulation is adopted as the material of the submount member 30, and the LED chip 10 has two adjacent corners of the four corners on one surface side. An anode electrode 13a (see FIG. 7 and FIG. 8A) is formed, and a cathode electrode 13b (see FIG. 7 and FIG. 8A) is formed at the remaining two locations. Each of 13a is electrically connected to one conductor pattern 73 via bonding wire 14, and each cathode electrode 13b is electrically connected to the other conductor pattern 73 via bonding wire 14. Here, the resist layer 76 of the wiring substrate 74 is patterned so that two portions of each conductor pattern 73 are exposed in the vicinity of the window hole 75 and one portion of each conductor pattern 73 is exposed in the peripheral portion of the wiring substrate 74. In each conductor pattern 73, two portions exposed in the vicinity of the window hole 75 constitute a terminal portion 73a to which the bonding wire 14 is connected, and a circular portion exposed in the peripheral portion of the resist layer 76 is an external portion. The electrode part 73b for connection is comprised. Of the two electrode portions 73b, the electrode portion 73b (the right electrode portion 73b in FIG. 7) to which each anode electrode 13a of the LED chip 10 is electrically connected is formed with a “+” sign, and the LED chip. Since the symbol “-” is formed on the electrode portion 73b (the left electrode portion 73b in FIG. 7) to which the ten cathode electrodes 13b are electrically connected, both electrode portions 73a and 73b in the light emitting device 1 are formed. Can be visually recognized, and erroneous connection can be prevented.

  Here, in this embodiment, the window hole 75 in the wiring board 74 is rectangular, and as shown in FIG. 8A, the terminal portion 73a is provided near the center of each side of the rectangular window hole 75. Although provided, as shown in FIG. 8B, by providing the terminal portion 73a in the vicinity of one end of each side of the window hole 75, the entire length of the bonding wire 14 can be increased, and the reliability is improved. To do.

  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.

  As the sealing resin that is the material of the sealing portion 150 described above, a silicone resin is used. However, the sealing resin is not limited to the silicone resin, and for example, an acrylic resin may be used.

  The optical member 160 is a molded product of a translucent material (for example, silicone) and is formed in a dome shape. Here, in the present embodiment, since the optical member 160 is formed of a silicone molded product, the refractive index difference and the linear expansion coefficient difference between the optical member 160 and the sealing portion 150 can be reduced. In addition, when the material of the sealing part 150 is an acrylic resin, it is preferable to form the optical member 160 also with an acrylic resin.

  Further, the optical member 160 has a light exit surface 160b formed in a convex curved surface shape that does not totally reflect light incident from the light incident surface 160a at the boundary between the light exit surface 160b and the air layer 180 described above. 10 and the optical axis coincide with each other. Therefore, the light emitted from the LED chip 10 and incident on the light incident surface 160a of the optical member 160 can easily reach the color conversion member 170 without being totally reflected at the boundary between the light emitting surface 160b and the air layer 180, The total luminous flux can be increased. The light emitted from the side surface of the LED chip 10 propagates through the sealing portion 150, the optical member 160, and the air layer 180 to reach the color conversion member 170 to excite the phosphor of the color conversion member 170 or to the phosphor. Passes through the color conversion member 170 without colliding. Further, the optical member 160 is formed so that the thickness is uniform along the normal direction regardless of the position.

  The color conversion member 170 is a mixture formed by mixing a translucent material such as silicone and a particulate yellow phosphor that emits broad yellow light when excited by the blue light emitted from the LED chip 10. (That is, the color conversion member 170 contains a phosphor). 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 170b of the color conversion member 170 to obtain white light. Can do. The translucent material used as the material of the color conversion member 170 is not limited to silicone, and for example, acrylic resin, glass, or the like may be employed. Further, the phosphor mixed with the translucent material used as the material of the color conversion member 170 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 170 is formed such that the inner surface 170 a is along the light emitting surface 160 b of the optical member 160. Therefore, the distance between the light emitting surface 160b and the inner surface 170a of the color conversion member 170 in the normal direction is a substantially constant value regardless of the position of the light emitting surface 160b of the optical member 160. Note that the color conversion member 170 is formed so that the thickness along the normal direction is uniform regardless of the position.

  In the light emitting device 1 according to this embodiment, since the air layer 180 is formed between the color conversion member 170 and the optical member 160, the color conversion member 170 is deformed when an external force is applied to the color conversion member 170. It is possible to suppress the stress generated in the color conversion member 170 due to the external force from being transmitted to the LED chip 10 and each bonding wire 14 through the optical member 160 and the sealing portion 150 because the possibility of coming into contact with the optical member 160 is reduced. Since the variation of the light emission characteristics of the LED chip 10 due to the external force and the disconnection of each bonding wire 14 are less likely to occur, there is an advantage that the reliability is improved. In addition, since the air layer 180 is formed between the color conversion member 170 and the optical member 160, the moisture in the external atmosphere is less likely to reach the LED chip 10, and the LED chip 10 is radiated. Light that is incident on the color conversion member 170 through the sealing unit 150 and the optical member 160 and is scattered by the yellow phosphor particles in the color conversion member 170 is scattered toward the optical member 160 and transmitted through the optical member 160. Therefore, there is an advantage that the light extraction efficiency of the light emitting device 1 as a whole can be improved.

  In the light emitting device 1 of the present embodiment, the thickness dimension of the submount member 30 is such that the surface of the submount member 30 is farther from the conductive plate 21 than the one surface of the wiring board 74 (the surface of the resist layer 76). The light emitted from the LED chip 10 to the side can be prevented from being absorbed by the wiring board 74 through the inner peripheral surface of the window hole 75 of the wiring board 74.

  By the way, in the manufacturing method of the light-emitting device 1 described above, for example, after the LED chip 10 and each of the conductor patterns 73 and 73 are electrically connected through the two bonding wires 14, respectively, as shown in FIG. A part of the sealing portion 150 is placed in the gap between the submount member 30 and the wiring board 74 so that the tip of the nozzle 401 of the dispenser 400 is aligned with the resin injection hole 78 formed continuously to the window hole 75 of the wiring board 74. The liquid sealing resin (for example, silicone resin) to be used is injected and cured, and then the liquid sealing resin (the remaining portion of the sealing portion 150 described above is formed inside the dome-shaped optical member 160). For example, after the silicone resin is injected, the sealing member 150 is formed by placing the optical member 160 at a predetermined position on the chip mounting member 70 and curing the sealing resin. At the same time, it is conceivable that the optical member 160 is fixed to the chip mounting member 70 and then the color conversion member 170 is fixed to the chip mounting member 70. Since bubbles (voids) may be generated in the stopper 150, it is necessary to inject a large amount of liquid sealing resin into the optical member 160. However, when such a manufacturing method is employed, a part of the liquid sealing resin is surrounded by the optical member 160 and the chip mounting member 70 when the optical member 160 is disposed at the predetermined position in the chip mounting member 70. The entire light-emitting device 1 overflows from the space and spreads on the surface of the resist layer 76, due to light absorption at an unnecessary portion made of the overflowing sealing resin, light irregular reflection due to unevenness of the unnecessary portion, and the like. As a result, the light extraction efficiency decreases.

  Therefore, in the light emitting device 1 of the present embodiment, between the portion overlapping the ring-shaped end edge of the optical member 160 and the portion overlapping the ring-shaped end edge of the color conversion member 170 on the one surface of the chip mounting member 70. A plurality of resin reservoir holes 77 for storing the sealing resin overflowing from the space surrounded by the optical member 160 and the chip mounting member 70 are formed apart from each other in the outer peripheral direction of the optical member 160. Here, the resin reservoir hole 77 includes a through hole 77 a formed in the wiring substrate 74 and a recess 77 b formed in a portion corresponding to the through hole 77 a in the conductive plate 71. Further, in the light emitting device 1 of the present embodiment, on the one surface side of the chip mounting member 70, between the portion overlapping the ring-shaped end edge of the optical member 160 and the portion overlapping the ring-shaped end edge of the color conversion member 170. And a ring-shaped light absorption preventing substrate 40 that covers each resin reservoir hole 77, and absorbs light by a resin portion made of a sealing resin that has accumulated and cured in each resin reservoir hole 77. This can be prevented by the light absorption preventing substrate 40. Here, since the light absorption preventing substrate 40 is provided with a white resist layer that reflects light from the LED chip 10 or the color conversion member 170 on the surface side opposite to the chip mounting member 70 side, The absorption of the light can be prevented. The light absorption preventing substrate 40 is formed after the sealing resin overflowing when the optical member 160 is disposed at a predetermined position in the chip mounting member 70 is filled in each resin reservoir hole 77. It is sufficient to place it on the one surface side of 70, and when the sealing resin is cured thereafter, it is fixed to the chip mounting member 70 by the sealing resin. Here, the ring-shaped light absorption preventing substrate 40 is formed with a plurality of notches 42 for exposing minute regions of the resin reservoir holes 77, and the sealing resin in the resin reservoir holes 77 is cured. It is possible to prevent voids from being generated.

  In the light emitting device 1 of the present embodiment described above, as in the first embodiment, in order to join the conductive plate 71 to the instrument main body 90 that is a metal member that holds the chip mounting member 70, Since the sheet-like joining member 80 which is disposed on the other surface side and has an electrical insulation property and thermally couples the conductive plate 71 and the instrument main body 90 is provided, the rubber sheet-like heat dissipation sheet is attached to the instrument. Compared with the case where the LED chip 10 is interposed between the light emitting part and the metal member holding the chip mounting member, the heat resistance can be reduced and the heat dissipation can be improved and the thermal resistance can be varied. Since the temperature rise of the junction temperature of the LED chip can be suppressed, the input power can be increased and the light output can be increased.

  Further, in the light emitting device 1 of this embodiment, since the planar size of the joining member 80 is set larger than the planar size of the conductive plate 71, the joining member 80 and the conductive plate 71 have the same planar size. Compared with the case where it is formed, the creeping distance between the conductive plate 71 and the appliance main body 90 that is a metal member can be increased, and the lightning surge resistance when used as a light source for a lighting fixture can be improved. (However, the creepage distance between the light emitting device and the metal member, which is generally required for indoor lighting fixtures and outdoor lighting fixtures, is different, and outdoor lighting fixtures are required to have longer creepage distances. ) Here, the thickness of the sheet-like joining member 80 needs to be designed in accordance with the lightning surge resistance required withstand voltage, but it is desirable to set it thinner from the viewpoint of reducing thermal resistance. Therefore, regarding the joining member 80, after setting the thickness, the plane size may be set so as to satisfy the requirement of the creepage distance.

  By the way, in the lighting fixture demonstrated in Embodiment 1, although each light-emitting device 1 is connected suitably by the lead wire 93 (refer FIG. 1 and FIG. 4), the lighting fixture in this embodiment is shown to FIG. 10 and FIG. As shown, the circuit board 300 is provided with a wiring pattern 302 that defines the connection relationship of each light emitting device 1 formed on one surface side of the insulating base material 301. In the present embodiment, the plurality of light emitting devices 1 are connected in series. However, the connection relationship between the plurality of light emitting devices 1 is not particularly limited. For example, the light emitting devices 1 may be connected in parallel or connected in series. And parallel connection may be combined.

  The circuit board 300 is disposed in the instrument main body 90 so as to be separated from the bottom wall 90a of the instrument main body 90, and has an opening through which a part of each light emitting device 1 is passed through a portion corresponding to each light emitting device 1. A window 304 is formed. In addition, as a material of the insulating base material 301 of the circuit board 300, for example, a glass epoxy resin such as FR4 may be adopted, but not limited to a glass epoxy resin, for example, a polyimide resin, a phenol resin, or the like may be used. .

  The circuit board 300 is provided with a wire insertion hole 306 through which a lead wire for power supply inserted through an insertion hole 90c formed in the bottom wall 90a of the instrument body 90 is inserted. A pair of electric wires inserted through 306 are electrically connected. Further, the circuit board 300 has a light reflecting layer 303 formed of a white resist layer on the surface side opposite to the bottom wall 90 a side of the instrument main body 90, and most of the wiring pattern 302 is the light reflecting layer 303. Covered by.

  In the circuit board 300, the opening size of each opening window 304 is set to be slightly larger than the planar size of the chip mounting member 70 in the light emitting device 1. Here, in the light emitting device 1 of the present embodiment, the chamfered portions are formed at the four corners in plan view of the chip mounting member 70 to be rounded, but the chamfered portions in the vicinity of each electrode portion 73b (the left and right chamfered portions in FIG. The radius of curvature of the remaining two chamfered portions (upper and lower chamfered portions in FIG. 7) is larger than that of the first portion of the circuit board 300. Can be bigger. In addition, in order to prevent an overvoltage from being applied to the LED chip 10 of the light emitting device 1, the circuit board 300 is provided with a surface mount type Zener diode 331 (see FIG. 11) for preventing overvoltage and a surface mount type ceramic. A capacitor 332 (see FIG. 11) is mounted in the vicinity of each opening window 304.

  By the way, in the light emitting device 1 of the present embodiment, each electrode portion 73 b of the chip mounting member 70 is electrically connected to the wiring pattern 302 of the circuit board 300 through the terminal plate 310. Here, the terminal plate 310 forms a terminal piece 311 that is joined to the wiring pattern 302 in the form of overlapping the thickness direction by bending one end of an elongated metal plate into an L shape, and the other end is The terminal piece 312 is formed by being bent in a J-shape to be joined to the electrode portion 73b so that the thickness direction coincides with the electrode portion 73b, resulting from a difference in linear expansion coefficient between the instrument body 90 and the circuit board 300. The stress generated at the joint between the connection terminal 310, the electrode part 73b, and the wiring pattern 302 can be relaxed, and the connection reliability between each light emitting device 1 and the circuit board 300 can be improved.

  In each of the above-described embodiments, each light emitting device 1 includes the joining member 80. However, the planar size of the joining member 80 is increased, and one joining member 80 is replaced with a plurality of light emitting devices. 1 may be shared.

It is a principal part schematic sectional drawing of the state which mounted the light-emitting device of Embodiment 1 in the fixture main body of a lighting fixture. It is a general | schematic disassembled perspective view of the light-emitting device same as the above. It is the schematic side view in which the lighting fixture in the same as the above was fractured. It is a principal part schematic perspective view of the lighting fixture in the same as the above. 6 is a schematic cross-sectional view of a light emitting device according to Embodiment 2. FIG. It is a principal part schematic disassembled perspective view of the lighting fixture using the light-emitting device same as the above. It is explanatory drawing of the manufacturing method of a light-emitting device same as the above. It is principal part explanatory drawing of a light-emitting device same as the above. It is a general | schematic disassembled perspective view of a light-emitting device same as the above. It is a principal part schematic disassembled perspective view of the lighting fixture using the light-emitting device same as the above. It is a principal part schematic perspective view of the lighting fixture using the light-emitting device same as the above. It is a schematic sectional drawing of the light-emitting device (LED unit) which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting device 10 LED chip 11 Conductive substrate 12 Light-emitting part 30 Submount member 70 Chip mounting member 71 Conductive plate (heat-transfer plate)
72 Insulating part 73 Conductor pattern 80 Joining member 90 Instrument body (metal member)

Claims (5)

  An LED chip, a heat transfer plate made of a heat conductive material on which the LED chip is mounted on one surface side, and a conductor pattern provided on the one surface side of the heat transfer plate via an insulating portion and electrically connected to the LED chip A chip mounting member, and a heat transfer plate disposed on the other side of the heat transfer plate for joining the heat transfer plate to a metal member holding the chip mounting member. A light-emitting device comprising: a sheet-like joining member that thermally couples a metal member.   The light emitting device according to claim 1, wherein the LED chip includes a light emitting portion formed of a GaN-based compound semiconductor material on a main surface side of a conductive substrate made of a SiC substrate or a GaN substrate.   A submount member that is larger than the chip size of the LED chip and is interposed between the LED chip and the heat transfer plate to relieve stress acting on the LED chip due to a difference in linear expansion coefficient between the two. The light-emitting device according to claim 1 or 2.   The light emitting device according to any one of claims 1 to 3, wherein the joining member is made of a resin sheet containing a filler made of a filler and having a low viscosity when heated.   5. The light emitting device according to claim 1, wherein the joining member has a planar size larger than that of the heat transfer plate.

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