Patent Publication Number: US-9423118-B2

Title: Light-emitting module and lamp using same

Description:
TECHNICAL FIELD 
     The present invention pertains to a light-emitting module using a semiconductor light-emitting element, and in particular to technology for improving thermal dissipation therein. 
     BACKGROUND ART 
     In recent years, semiconductor light-emitting elements such as light-emitting diodes (hereinafter, LEDs) have been expected to become a new light source for lamps, due to their high efficiency and long useful life in comparison to incandescent and halogen light bulbs. The light output of such LED chips decreases as temperature increases. Accordingly, constraining temperature increases is an important concern in a lamp using the LED chips. 
     Conventional lamps have been proposed in which temperature increases are constrained for the LED chips (see Patent Literature 1 and 2). 
     The lamps described in Patent Literature 1 and 2 each include a substrate, a light-emitting module made up of a plurality of LED chips mounted on the substrate, a mount on which the light-emitting module is mounted, and a case holding the mount therein such that a part of the lamp remains exposed. The mount and the case are formed as a common whole. In these lamps, heat is produced by the LED chips and transferred through the mount and then effectively transferred to the case, thus constraining temperature increases of the LED chips. 
     Generally, these lamps use a light-emitting module in which the LED chips are affixed to the substrate by an adhesive made of silicone resin. As such, the heat produced by the LED chips is transferred to the substrate via the adhesive made of silicone resin. 
     CITATION LIST 
     Patent Literature 
     
         
         [Patent Literature 1] 
         Japanese Patent Application Publication No. 2006-313717 
         [Patent Literature 2] 
         Japanese Patent Application Publication No. 2009-037995 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in recent years, demand for high-brightness lamps has increased, leading to high-output LED chips being used. As such, large amounts of heat are produced by these high-output LED chips. 
     However, the lamps described in Patent Literature 1 and 2 have not benefited from improvements to the heat transfer properties of the adhesive attaching the LED chips to the substrate. Accordingly, insufficient heat transfer occurs between the LED chips and the substrate, leading to a risk that the temperature increases of the LED chips are not sufficiently constrained. 
     In consideration of the above-described situation, the present invention aims to provide a light-emitting module that provides improvements to the heat transfer properties of semiconductor light-emitting elements. 
     Solution to Problem 
     In order to solve the above-described problem, a light-emitting module pertaining to the present disclosure comprises: a substrate; a semiconductor light-emitting element arranged on a main surface of the substrate; a wavelength conversion member disposed on the main surface of the substrate so as cover the semiconductor light-emitting element and converting a wavelength of light radiating from the semiconductor light-emitting element, and a heat transfer member thermally connecting at least a portion of an outer circumferential surface of the semiconductor light-emitting element with the main surface of the substrate, and transferring heat produced by the semiconductor light-emitting element to the substrate, wherein the heat transfer member includes a base material that is optically transmissive, and particles of an optically transmissive material that are dispersed within the base material and have higher thermal conductivity than the base material. 
     Advantageous Effect of Invention 
     According to this configuration, the light-emitting module includes a heat transfer member thermally connecting at least a portion of the outer circumferential surface of the semiconductor light-emitting element with the main surface of the substrate, and transferring heat produced by the semiconductor light-emitting element to the substrate, while the heat transfer member includes a base material that is optically transmissive, and particles of an optically transmissive material that are dispersed within the base material and have higher thermal conductivity than the base material. Thus, heat produced by the semiconductor light-emitting element is more effectively transferred to the substrate via the heat transfer member in comparison with a configuration in which the heat transfer member only includes the base material. Accordingly, constraints on temperature increases in the semiconductor light-emitting element are promoted. 
     Also, the heat transfer member is made of an optically transmissive base material and of particles that are dispersed throughout the base material, are optically transmissive, and have higher thermal conductivity than the base material. Thus, the light emitted by the semiconductor light-emitting element is not obstructed by the heat transfer member and is prevented from decreasing in output efficacy. Furthermore, the configuration in which the heat transfer member is made of a base material and particles having greater thermal conductivity than the base material provides an additional degree of freedom to heat transfer member design. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIGS. 1A through 1D  show a light-emitting module pertaining to Embodiment 1, where  FIG. 1A  shows a plan view,  FIG. 1B  shows a cross-section taken along chained line A-A′ in the direction of the arrows,  FIG. 1C  shows a magnified cross-section of the area encircled by chained line A 1 , and  FIG. 1D  shows a cross-section taken along line B-B′ in the direction of the arrows. 
         FIG. 2A-1  shows a partial cross-section of a light-emitting module pertaining to a comparative example,  FIG. 2A-2  is a thermal circuit diagram describing heat dissipation characteristics of the light-emitting module pertaining to the comparative example,  FIG. 2B-1  shows a partial cross-section of a light-emitting module pertaining to Embodiment 1, and  FIG. 2B-2  is a thermal circuit diagram describing heat dissipation characteristics of the light-emitting module pertaining to Embodiment 1. 
         FIGS. 3A, 3B, and 3C  each illustrate a thermal propagation path through the heat transfer member in the light-emitting module pertaining to Embodiment 1. 
         FIGS. 4A and 4B  illustrate optical properties of the heat transfer member pertaining to Embodiment 1. 
         FIGS. 5A and 5B  describe optical properties of the heat transfer member pertaining to Embodiment 1. 
         FIGS. 6A through 6E  are cross-sectional diagrams illustrating steps of a manufacturing method for the light-emitting module pertaining to Embodiment 1. 
         FIG. 7  shows a partial cross-section of a light-emitting module pertaining to Embodiment 2. 
         FIG. 8  describes heat dissipation properties of a heat transfer member pertaining to Embodiment 1. 
         FIGS. 9A, 9B, and 9C  illustrate the light-emitting module pertaining to Embodiment 3, where  FIG. 9A  shows a plan view,  FIG. 9B  shows a plan view of the area outlined by dashed line A 2  in  FIG. 9A  without the sealing member, and  FIG. 9C  shows a partial cross-section. 
         FIGS. 10A and 10B  illustrate a lamp pertaining to Embodiment 3, where  FIG. 10A  is a perspective view and  FIG. 10B  is a cross-section. 
         FIG. 11  shows a perspective view of a lamp unit pertaining to Embodiment 4. 
         FIG. 12  shows an exploded view of the lamp unit pertaining to Embodiment 4. 
         FIG. 13  shows a cross-section of a lighting apparatus pertaining to Embodiment 5. 
         FIGS. 14A and 14B  show a partial cross-section of a light-emitting module pertaining to a variant. 
         FIG. 15  shows a partial cross-section of a light-emitting module pertaining to a variant. 
         FIGS. 16A and 16B  show a partial cross-section of a light-emitting module pertaining to a variant. 
         FIG. 17  shows a partial cross-section of a light-emitting module pertaining to a variant. 
         FIGS. 18A and 18B  show a partial cross-section of a light-emitting module pertaining to a variant. 
         FIG. 19  shows a partial cross-section of a light-emitting module pertaining to a variant. 
         FIGS. 20A and 20B  illustrate a light-emitting module pertaining to a variant, where  FIG. 20A  shows a plan view with a sealing member partially removed and  FIG. 20B  is a partial cross-section. 
         FIGS. 21A, 21B, and 21C  show a partial cross-section of a light-emitting module pertaining to a variant. 
         FIG. 22  shows a cross-section of a lamp pertaining to a variant. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiment 1 
     (1) Overall Configuration 
       FIG. 1A  shows a plan view of a light-emitting module  1  pertaining to the present Embodiment.  FIG. 1B  is a cross-sectional view taken along line A-A′ of  FIG. 1A , and  FIG. 1C  is a magnified view of an encircled portion A 1  of  FIG. 1B . 
     As shown in  FIG. 1A , the light-emitting module  1  includes a substrate  110 , a plurality of LED chips (i.e., semiconductor light-emitting elements)  120  arranged in two rows on the substrate  110 , a wiring pattern  130  for supplying electric power to each LED chip  120 , and a sealing member  140  sealing the LED chips  120  into row units. Also, as shown in  FIG. 1C , the light-emitting module  1  has die attach members  150  for attaching each LED chip  120  to the substrate  110 , and a heat transfer member  160  for dissipating heat produced by the LED chips  120  to the substrate  110 . 
     (1-1) Substrate 
     As shown in  FIG. 1A , the substrate  110  is rectangular in a plan view, and has through-holes  112  formed at each longitudinal end for connecting leads supplying power from a power source circuit to the LED chips  120 . Also, a through-hole  114  is formed at the approximate centre of the substrate  110  for the sake of convenience when fixing the substrate  110  to a heat sink or the like. The substrate  110  is not limited to being rectangular in a plan view, and may instead be elliptical or polygonal. Further, the through-holes  112  and  114  may or may not be formed therein. 
     The substrate  110  is, for example, formed of a ceramic material that is highly thermoconductive and has excellent heat dissipation properties. Also, the substrate  110  is transparent to visible light. Accordingly, despite the LED chips  120  being mounted on only one side of the substrate  110 , light radiating from the LED chips  120  is also emitted through the far side, with respect to the thickness dimension of the substrate  110 . As such, omnidirectional flux distribution is achieved. Aluminium oxide (Al 2 O 3 ), which is a ceramic material having 96% optical transmissiveness, is usable as the material for the substrate  110 . The material for the substrate  110  is not limited to a ceramic, but may also be resin or glass. Also, a metal material (such as aluminium) may be used when flux distribution is not a consideration. 
     (2-2) LED Chip 
     As shown in  FIG. 1A , the LED chips  120  include twenty LED chips  120  arranged longitudinally on the substrate  110  to form two element rows. The element rows are disposed in parallel along the longitudinal direction of the substrate  110  so as to sandwich through-hole  112 . The LED chips  120  are not limited to being twenty in number. The number of LED chips may be adjusted according to the usage mode of the light-emitting module  1 . Also, the LED chips  120  may be arranged into a single element row, or may be arranged into three or more element rows. 
     As shown in  FIG. 1B , each LED chip  120  is a surface mounted LED (i.e., chip-on-board, hereinafter COB). Also, as shown in  FIG. 1C , an electrode (not diagrammed) is disposed over the top face of each LED chip  120 . The LED chips  120  are connected in series by metal wires  122  that link the electrodes of neighbouring LED chips  120 . 
     Each LED chip  120  emits blue light and is formed of GaN (gallium nitride) material An individual LED chip  120  emits light from an active layer formed of a semiconductor sandwiched between an N-type semiconductor cladding layer and a P-type semiconductor cladding layer. Further, each LED chip  120  is cuboid in shape. The light emitted by the active layer of each LED chip  120  radiates outward not only from the top and bottom faces of the LED chip  120 , but also from the four side faces thereof. That is, the light-emitting surface of each LED chip  120  includes the top face, the bottom face, and the four side faces. In addition, each LED chip  120  produces heat as well as light. 
     (1-3) Wiring Pattern 
     As shown in  FIG. 1A , the wiring pattern  130  is formed at each longitudinal end of the substrate  110 . The wiring pattern  130  is made up of a land portion  130   a  disposed on the substrate  110  at the outer circumference of through-hole  112 , and two leg portions  130   b  formed on the substrate  110  so as to respectively extend from one of the latitudinal sides of the land portion  130   a  along two neighbouring edges of the substrate  110 . The two element rows are then disposed between the portions of the wiring pattern  130  formed at each longitudinal end of the substrate  110 . Here, the land portions  130   a  of the wiring pattern  130  are electrically connected to the lead passing through each of the through-holes  112  in the substrate  110 , by means of solder or the like. One of the two portions of the wiring pattern  130  is connected to an output terminal on the high-potential side of the power source circuit, while the other portion is connected to an output terminal on the low-potential side of the power source circuit. The wiring pattern  130  is formed from an electrically conductive material, such as Ag (silver), W (tungsten), Cu (copper), ITO (Indium-Tin Oxide) or similar. Also, as shown in  FIG. 1C , the leg portions  130   b  in the wiring pattern  130  and the LED chip  120  are electrically connected by the metal wire  124 . 
     A Ni (nickel), Au (gold), or similar plating process may be applied to the surface of the wiring pattern. Likewise, a coating of glass or the like may be applied to surface of the wiring pattern, with the exception of land portions  130   a  and the ends of the leg portions  130   b  opposite the ends thereof connected to the land portion  130   a  (i.e., at a position bonded to the end of the metal wire  124 ). Further, one of the two portions of the wiring pattern  130  may be grounded. 
     (1-4) Sealing Member 
     As shown in  FIG. 1A , the sealing member  140  is formed along the longitudinal direction of the substrate  110  so as to cover each of the two element rows described above. The sealing member  140  is formed of an optically transmissive resin material that contains fluorescent particles. The sealing member  140  serves as a wavelength conversion member that changes the wavelength of the light emitted by the LED chips  120 . 
     The optically transmissive resin material may be, for example, a silicone resin, a fluorine resin, a silicone-epoxy hybrid resin, a urea-formaldehyde resin, an epoxy resin, a urethane resin, an acrylic resin, a polycarbonate resin, and so on. The material used for the sealing member  140  is not limited to being an optically transmissive resin, but may also be glass or similar material having SiO 2  or the like as a principal component. Alternatively, the material for the sealing member may be an organic-inorganic hybrid translucent body. The organic-inorganic hybrid translucent body is made of glass and resin. 
     The fluorescent particles are, for example, pulverized YAG fluorescent particles ((Y, Gd) 3 Al 5 O 12 :Ce 3+ ), silicate fluorescent particles ((Sr, Ba) 2 SiO 4 :Eu 2+ ), nitride fluorescent particles ((Ca, Sr, Ba)AlSiN 3 :Eu 2+ ), or oxynitride fluorescent particles (Ba 3 Si 6 O 12 N 2 :Eu 2+ ). Accordingly, the blue light radiating from the LED chips  120  is partially converted by the fluorescent particles into yellow light, which is emitted in combination with the blue light to produce white light. The sealing member  140  need not necessarily include the fluorescent particles. Also, the LED chips  120  are protected against degradation as a result of being sealed by the sealing member  140 . 
     (1-5) Die Attach Member 
     As shown in  FIGS. 1C and 1D , a die attach member  150  is interposed between each LED chip  120  and the main surface of the substrate  110 , and serves to affix each LED chip  120  to the substrate  110 . The die attach member  150  is, for example, made from an adhesive that includes an optically transmissive thermoconductive resin, such as silicone resin. As such, the die attach member  150 , being optically transmissive, propagates light emitted from the bottom face of the LED chip  120  mounted thereon to the inside of the substrate  110 . 
     The thermal resistance of the die attach member  150  is calculated according to Math. 1, below. 
     
       
         
           
             
               
                 
                   
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     Here, RthD is the thermal resistance of the die attach member  150 , TD is the thickness of the die attach member  150 , SD is the cross-sectional area of the die attach member  150 , and κD is the thermal conductivity of the die attach member  150 . 
     For example, when the die attach member  150  has external dimensions of 365 μm×365 μm×2 μm and is made of silicone resin, then given that the thermal conductivity of silicone resin is 0.15 W/m·K, Math. 1 gives the thermal resistance of the die attach member  150  as approximately 100 K/W. 
     (1-6) Heat Transfer Member 
     The heat transfer member  160  serves to dissipate the heat produced by the LED chips  120  emitting light to the substrate  110 . As shown in  FIGS. 1C and 1D , the heat transfer member  160  is disposed on the substrate  110  at an outer circumferential area of each LED chip  120 , adheres to the four side faces of each LED chip  120 , and thermally connects each LED chip  120  to the substrate  110 . Above, thermally connecting refers to creating a state in which the two components so connected are able to transfer heat from one to the other. No connection exists between the heat transfer members  160  disposed at the outer circumferential area of two neighbouring LED chips  120 . 
     The heat transfer member  160  is made up of an optically transmissive base material having particles of a highly optically transmissive material dispersed therein, which has higher thermal conductivity than the base material. Specifically, the heat transfer member  160  is formed of a composite material  162 , which includes silicone resin as the optically transmissive base material and nanoparticles dispersed in the silicone material, and of microparticles  161 . The nanoparticles and microparticles are particles of a highly optically transmissive material having higher thermal conductivity than the base material. The composite material  162  is hereinafter termed a nanocomposite. The nanocomposite  162  serves to contain the microparticles  161 . The nanoparticles are particles having an average diameter that is equal to or less than the 450 nm wavelength of blue light. The microparticles  161  are particles having an average diameter of 1 μm to 100 μM inclusive, which is greater than the 660 nm wavelength of red light. The material for the nanoparticles and the microparticles  161  is, for example, any of ZnO, MgO, sapphire, Al 2 O 3 , Y 2 O 3 , TiO 2 , and ZrO 2 . As mentioned, the nanoparticles and microparticles are formed of an optically transmissive material. However, this excludes the fluorescent particles. Accordingly, the light radiating from the LED chips  120  does not undergo wavelength conversion upon passing through the heat transfer member  160 . Configuring the heat transfer member  160  such that no wavelength conversion occurs therein enables the colour of the light emitted from the light-emitting module  1  to be determined solely according to the colour of the light emitted from the LED chips  120  and the colour of the light converted by the sealing member  140 . As such, the colour of the light emitted by the light-emitting module  1  is beneficially made easier to adjust. 
     Considering that the wavelength band of visible light is greater than 450 nm and less than 750 nm, the average diameter of the microparticles  161  is greater than the wavelength of visible light, and the average diameter of the nanoparticles is smaller than the wavelength of visible light. 
     The aforementioned sapphire has a thermal conductivity of 42 W/m·K, the Al 2 O 3  has a thermal conductivity of 36 W/m·K, the Y 2 O 3  has a thermal conductivity of 11 W/m·K, the ZnO and the MgO both have a thermal conductivity of 54 W/m·K, and the ZrO 2  has a thermal conductivity of 3.0 W/m·K. All of the above ceramic materials have a thermal conductivity that is greater than that of silicone resin, which is 0.15 W/m·K. These ceramics may be used as the materials for the microparticles  161  and the nanoparticles within the heat transfer member  160 . For instance, the microparticles  161  may be formed of MgO and the nanoparticles may be formed of ZrO 2 . In such circumstances, the MgO making up the microparticles  161  has higher thermal conductivity than the ZrO 2  making up the nanoparticles. 
     The microparticles  161  may include a plurality of particle types each having a different average diameter. For instance, when two types of microparticles that differ in average diameter are used, the type of microparticle having the smaller average diameter (hereinafter, small microparticles) are beneficially no larger than a gap formed between neighbouring particles of the type having the larger average diameter (hereinafter, large microparticles) when the large microparticles are packed as densely as possible into the heat transfer member  160 . Accordingly, the microparticle  161  packing density within the heat transfer member  160  is increased, thus enabling improvements in heat transfer from the LED chip  120  to the substrate  110 . 
     The average diameter of the microparticles  161  and the nanoparticles is measured using dynamic light scattering (e.g., measured using the nanotrac-UT 151 from Nikkiso Co. Ltd.). The nanoparticles are then measured by mixing into an organic solvent or similar in which the nanoparticle density is less than 30 wt %. Accurate values are unobtainable with a density of 30 wt % or greater due to the multiple scattering effect. In the present document, the average diameter of the various particles corresponds to 50% of the cumulative particle volume, found by taking a total nanoparticle volume calculated from a particle diameter distribution obtained by measurement, and cumulatively adding the nanoparticle volumes beginning with the smallest particles. The average diameter of the microparticles  161  and the nanoparticles may also be found by breaking the heat transfer member  160  at a given position and observing the broken surface with a scanning electron microscope (hereinafter, SEM). 
     The heat transfer member  160  is in contact with the side faces of the LED chip  120 . However, the side faces are not limited to being four in number, and may instead be one, two, or three side faces. Also, the heat transfer member  160  is not limited to being in contact with the entirety of any given side face of each LED chip  120 . For instance, the heat transfer member  160  may be only in contact with a portion (e.g., a lower portion) of a side face of each LED chip  120 . 
     (2) Heat Dissipation Properties of Light-Emitting Module 
     The following describes the heat dissipation pathways of the light-emitting module  1  pertaining to the present Embodiment, in contrast to the heat dissipation pathways of a light-emitting module pertaining to a comparative example. 
       FIG. 2A-1  is a partial cross-section diagram of the light-emitting module pertaining to the comparative example, and  FIG. 2A-2  is a thermal circuit diagram indicating the heat dissipation properties of the light-emitting module pertaining to the comparative example. Likewise,  FIG. 2B-1  is a partial cross-section diagram of the light-emitting module  1  pertaining to the present Embodiment, and  FIG. 2B-2  is a thermal circuit diagram indicating the heat dissipation properties of the light-emitting module  1  pertaining to the present Embodiment. 
     The light-emitting module pertaining to the comparative example is configured such that heat produced by the LED chips  120  is dissipated to the substrate  110  via a heat dissipation path passing through the die attach member  150  (see arrow AR 1  in  FIG. 2A-1 ). Accordingly, the thermal circuit diagram shown in  FIG. 2A-2  is produced, where one of the LED chips  120  is the heat source P, the die attach member  150  has thermal resistance RthD, and the substrate  110  and housing enclosing the substrate  110  have thermal resistance RthH. 
     Conversely, as shown in  FIG. 2B-1 , the light-emitting module  1  is configured such that the heat produced by the LED chips  120  is dissipated to the substrate  110  via a heat dissipation path passing through the die attach member  150  (see arrow AR 1  of  FIG. 2B-1 ) and via an additional heat dissipation path passing through the heat transfer member  160  (see arrow AR 2  of  FIG. 2B-1 ). Accordingly, the thermal circuit diagram shown in  FIG. 2B-2  is produced, in which one of the LED chips  120  is the heat source P, the die attach member  150  has thermal resistance RthD, the heat transfer member  160  has thermal resistance Rthn, and the substrate  110  and housing containing the substrate  110  have thermal resistance RthH. As shown, the thermal resistance RthD corresponding to the die attach member  150 , disposed between the LED chip  120  and the substrate  110  (along with the housing thereof), and the thermal resistance Rthn corresponding to the heat transfer member  160  are connected in parallel. Accordingly, the synthetic thermal resistance of the die attach member  150  and the heat transfer member  160  is as expressed in Math. 2, below. 
     
       
         
           
             
               
                 
                   
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     Here, Rsyns is the synthetic thermal resistance, RthD is the thermal resistance of the die attach member  150 , and Rthn is the thermal resistance of the heat transfer member  160 . 
     Accordingly, the light-emitting module  1  pertaining to the present Embodiment is configurable such that the magnitude of the synthetic thermal resistance Rsyns of the die attach member  150  and the heat transfer member  160  is one-tenth of the thermal resistance RthD of the die attach member  150  alone. This is achieved by setting the thermal resistance Rthn of the heat transfer member  160  to be one-ninth of the thermal resistance RthD of the die attach member  150 . For example, given a thermal resistance RthD of 100 K/W for the die attach member  150 , the thermal resistance Rthn of the heat transfer member  160  is set to approximately 11 K/W. 
     Next, the thermal propagation path transmitting heat within the heat transfer member  160  is discussed with reference to  FIGS. 3A, 3B, and 3C . The thermal propagation path is the path taken by the heat produced by the LED chips  120  until dissipated to the substrate  110 . 
     In a situation such as that illustrated by  FIG. 3A , one of the microparticles  161  serves as a main thermal propagation path PT 10 . Thermal propagation path PT 10  solely involves the microparticle  161 , which has higher thermal conductivity than the nanocomposite  162 . 
     Alternatively, as shown in  FIG. 3B , the microparticle  161  that is in contact with the side wall of the LED chip  120  and the microparticle  161  that is in contact with the substrate  110  may be in contact with one another. In such a case, a main thermal propagation path PT 11  for the heat produced by the LED chip  120  involves entering the microparticle  161  that is in contact with the side wall of the LED chip  120 , and subsequently passing through a contact portion linking the two microparticles  161  in order to enter the microparticle  161  that is in contact with the substrate  110  and reach the substrate  110 . Here also, thermal propagation path PT 11  solely involves microparticles  161 , which have higher thermal conductivity than the nanocomposite  162 . 
     Further, as shown in  FIG. 3C , a main thermal propagation path PT 20  may be formed by the microparticle  161  that is in contact with the side face of the LED chip  120 , a microparticle  161  that is in contact with the main surface of the substrate  110 , and a portion of the nanocomposite  162  interlinking the two microparticles  161 . In such a case, thermal propagation path PT 20  includes a portion of the nanocomposite  162 , which has lower thermal conductivity than the microparticles  161 . As such, thermal propagation path PT 20  is less effective at heat dissipation in comparison to thermal propagation path PT 10  shown in  FIG. 3A  and thermal propagation path PT 11  shown in  FIG. 3B , due to the greater thermal resistance per unit length found therein. 
     Accordingly, the more microparticles  161  are contained in the heat transfer member  160 , the more likely the microparticles  161  are to be in contact with each other and form a thermal propagation path that solely involves microparticles  161 . Thus, the thermal resistance of the heat transfer member  160  is easily reduced. 
     (3) Optical Properties of Heat Transfer Member 
     Next, the optical properties of the heat transfer member  160  are discussed. 
       FIGS. 4A and 4B  illustrate optical properties of the heat transfer member pertaining to the present Embodiment. 
     A portion of the light radiated by one of the LED chips  120  enters the heat transfer member  160  from the side face of the LED chip  120  and, as shown in  FIGS. 4A and 4B , is transferred within the heat transfer member  160  such that a component thereof is radiated out from the heat transfer member  160 . 
     When the refractive index of the microparticles  161  is either greater or smaller than the refractive index of the nanocomposite  162 , then as shown in  FIG. 4A , optical scattering occurs at the interface between the microparticles  161  and the nanocomposite  162 . As a result, there is a risk that the efficiency of light extraction from the LED chip  120  may be diminished. 
     In contrast, when the microparticles  161  and the nanocomposite  162  have the same refractive index, then as shown in  FIG. 4B , optical scattering is constrained at the interface between the microparticles  161  and the nanocomposite  162 . As a result, the diminution in efficiency of light extraction from the LED chip  120  is prevented. 
     In the present Embodiment, the nanocomposite  162 , in which the nanoparticles are dispersed within a base material, has the refractive index of the base material when the volume fraction of the nanoparticles therein is 0%, and has the refractive index of the material making up the nanoparticles when the volume fraction of the nanoparticles is 100%. The following centres on the change in refractive index as a function of change in nanoparticle volume fraction from 0% to 100%. For example, suppose that the nanoparticles are made of ZrO 2  and the base material is silicone resin. In such a case, the refractive index of the nanocomposite when the nanoparticle volume fraction is 0% is equal to the refractive index of silicone resin, which is 1.4, and is equal to the refractive index of ZrO 2 , which is 2.4, when the nanoparticles volume fraction is 100%. When the nanoparticle volume fraction is between 0% and 100%, then the refractive index of the nanocomposite  162  has a value between 1.4 and 2.4. 
     The solid line in  FIG. 5A  indicates the relationship between the refractive index of the nanocomposite  162  and the volume fraction of the nanoparticle made of ZrO 2  and dispersed within the nanocomposite  162 .  FIG. 5B  lists the refractive index of silicone resin, ZrO 2 , and other materials, mainly ceramics. 
     In the present Embodiment, the refractive index of the nanocomposite  162  that partially makes up the heat transfer member  160  is made equal to the refractive index of MgO, which makes up the microparticles  161 , by adjusting the nanoparticle volume fraction in the nanocomposite  162 . As shown in  FIG. 5B , the refractive index of MgO is 1.72. As such, a nanoparticle volume fraction of approximately 25% suffices for the nanoparticles of ZrO 2  in the nanocomposite  162  (see the dashed lines of  FIG. 5A ). 
     Also, the nanocomposite  162  is prone to increasing fragility with increasing nanoparticle volume fraction. In particular, a nanoparticles volume fraction of 80% or greater increases the risk of nanocomposite  162  fragility. As such, achieving the desired refractive index by decreasing the nanoparticle volume fraction but using nanoparticles having a higher refractive index is beneficial in terms of decreasing nanocomposite  162  fragility. 
     Also, the nanoparticle volume fraction required to achieve equality with the refractive index of the microparticle  161  is decreased when the refractive index of the microparticles  161  is similar to the refractive index of the silicone resin. This is thus advantageous in terms of constraining nanocomposite  162  fragility. 
     (4) Light-Emitting Module Manufacturing Method. 
       FIGS. 6A through 6E  are cross-sectional diagrams illustrating steps of a manufacturing method for the light-emitting module  1  pertaining to the present Embodiment. 
     Firstly, as shown in  FIG. 6A , the LED chips  120  are disposed on one side of the substrate  110  with respect to the thickness dimension thereof. The LED chips  120  are then fixed to the substrate  110  by the die attach member  150 . In the present Embodiment, the LED chips  120  are twenty in number. 
     Next, as shown in  FIG. 6B , a mask  1000  in which a plurality of through-holes  1002  are formed is manufactured ahead of time and prepared by disposing the mask  1000  such that the through-holes  1002  each correspond to one of the LED chips  120 . The respective centres in the through-holes  1002  of the mask  1000  roughly correspond to the respective centres of the LED chips  120  disposed on the substrate  110 . Also, the through-holes  1002  are approximately rectangular as seen in a plan view, and have larger external dimensions than the LED chips  120 . 
     Next, as indicated by the arrow in  FIG. 6B , the substrate  110  and the mask  1000  are affixed to each other such that the LED chips  120  are slotted into the through-holes  1002  of the mask  1000 . At this point, a gap is formed between the side walls of the LED chips  120  and the inner walls of the through-hole  1002  in the mask  1000 . The mask  1000  is affixed to the substrate  110  such that each through-hole  1002  surrounds one of the LED chips  120 . The substrate  110  and the mask  1000  are affixed to each other by using an adhesive material (non-diagrammed) that has weaker adhesive power than the adhesive material used in making the silicone resin. 
     Afterward, as shown in  FIG. 6C , a liquid mixture  1160  that contains of the microparticles  161  and the nanocomposite  162 , which will become the heat transfer member  160 , fills the gap between the side walls of the LED chips  120  and the inner walls of the through-holes  1002  in the mask  1000 . The liquid mixture  1160  is produced by first blending the nanoparticles of ZnO 2  with the silicone resin, agitating the blend, then adding the microparticles  161  of MgO and agitating the resulting mixture. 
     The liquid mixture  1160  may be applied as shown in  FIG. 6C , by using a dispenser to sequentially fill the through-holes  1002  of the mask  1000 . Also, overflow of the liquid mixture  1160  from the through-hole  1002  is preventable by measuring the fill volume of the through-holes  1002  in advance and using a metered nozzle to deliver a predetermined fill volume. The fill volume is calculated according to the capacity of the through-holes  1002  and the volume of the LED chips  12 . 
     Next, as shown in  FIG. 6D , the mask  1000  peels away from the substrate  110  as the liquid mixture  1160  is applied at the circumference of the LED chips  120  (see  FIG. 6E ). Here, the liquid mixture  1160  does not flow along the top surface of the substrate  110  due to having comparatively high viscosity. 
     Then, heat is applied to the entirety of the substrate  110  to form the heat transfer member  160 . 
     Lastly, the adhesive used to affix the mask  1000  to the substrate  110  is selectively removed from the substrate  110  and the light-emitting module  1  is thus completed. 
     Ultimately, the light-emitting module  1  pertaining to the present Embodiment includes the heat transfer member  160 , which is thermally connected to the side face of the LED chip  120  and to the main surface of the substrate  110 , and serves to dissipate heat produced by the LED chip  120  to the substrate  110 . As such, the heat produced by the LED chip  120  is dissipated through the heat transfer member  160  to the substrate  110 , thus enhancing the constraint on temperature increases in the LED chip  120 . 
     Also, the heat transfer member  160  is made up of optically transmissive silicone resin, a nanocomposite  162  that is dispersed throughout the silicone resin and is also optically transmissive, and optically transmissive microparticles  161 . As such, the light emitted by the LED chips  120  is not blocked by the heat transfer member  160 , thus preventing diminution in the efficiency of light emitted by the LED chips  120 . 
     Furthermore, the heat transfer member  160  is made up of the nanocomposite  162  that includes the nanoparticles of ZrO 2  dispersed within the silicone resin, and of the microparticles  161 . The refractive index of the microparticles  161  is freely adjustable so as to match the refractive index of the nanocomposite  162  by changing the nanoparticle volume fraction within the nanocomposite  162 . Accordingly, the heat transfer member  160  gains a degree of freedom in terms of design by widening the range of materials available for use in the microparticles  161 . 
     Embodiment 2 
     The following describes a light-emitting module  2  pertaining to the present Embodiment. 
       FIG. 7  shows a partial cross-section of a light-emitting module  2  pertaining to the present Embodiment. 
     As shown, light-emitting module  2  is configured similarly to the light-emitting module  1  pertaining to Embodiment 1, differing only in that the heat transfer member  260  does not include the microparticles  161  and is instead made of the nanocomposite alone. The explanation of the present Embodiment is centred on the heat transfer member  260 . Components identical to those of Embodiment 1 use the same reference signs thereas, and explanations thereof are omitted. 
     The heat transfer member  260  serves to dissipate the heat produced by the LED chip  120  upon emitting light to the substrate  110 , similar to Embodiment 1. As shown in  FIG. 7 , the heat transfer member  260  is disposed between the substrate  110  and the intersection of the four side walls of the LED chip  120  with the substrate  110 . As such, the LED chip  120  and the substrate  110  are thermally connected. 
     The heat transfer member  260  is made up of the nanocomposite having nanoparticles of ZrO 2  dispersed throughout a base material of silicone resin. 
     Incidentally, the relationship indicated by Math. 3, below, is satisfied by the thermal conductivity of the nanocomposite and the volume fraction of nanoparticles dispersed throughout the nanocomposite. 
     
       
         
           
             
               
                 
                   
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     Here, Vd is the nanoparticle volume fraction, κm is the thermal conductivity of the nanocomposite, κd is the thermal conductivity of the material making up the nanoparticles, and κc is the thermal conductivity of the base material. 
     Specifically, the thermal conductivity of the silicone resin is 0.15 W/m·K, the thermal conductivity of ZnO and MgO is 54 W/m·K, the thermal conductivity of TiO is 8.0 W/m·K, and the thermal conductivity of ZrO 2  is 3.0 W/m·K. According to these thermal conductivity values and Math. 3, the relationship between the nanoparticle volume fraction and the thermal conductivity of the nanocomposite is as indicated by the curves plotted in  FIG. 8 . 
     As can be read from  FIG. 8 , using ZnO or MgO rather than ZrO 2  or TiO 2  as the material for the nanoparticles produces greater thermal conductivity with a lower volume fraction of nanoparticles. The nanocomposite grows increasingly fragile as the nanoparticle volume fraction increases. Accordingly, the material used for the nanoparticles is beneficially one that achieves a greater thermal conductivity with a lower volume fraction. Thus, for example, ZnO or MgO is beneficial in terms of light-emitting module  2  reliability. 
     In practice, nanoparticles made of ZrO 2  and having an average diameter of 4.0 nm are added to the silicone resin to create the nanocomposite. This is known to cause no clouding and to be optically transmissive to visible light. Such a nanocomposite is, as shown in  FIG. 7 , disposed such that the heat transfer member  260  is able to be in contact with each of the four side faces of the LED chip  120 , which are light-emitting surfaces. 
     Accordingly, when the heat transfer member  260  is made of nanocomposite having nanoparticles of ZrO 2  dispersed therein, the optical efficiency produced by the LED chip  120  is maintained while providing improvements to the thermal conductivity in contrast to using silicone resin alone. 
     In order to reduce the synthetic thermal resistance of the die attach member  150  and the heat transfer member  260  to one-tenth of the die attach member  150  thermal resistance RthD in the light-emitting module  2 , as explained above in the discussion of Math. 2, the heat transfer member  260  thermal resistance should be set to one-ninth of the die attach member  150  thermal resistance. 
     For example, given a thermal resistance of 2 K/W for the die attach member  150 , the thermal resistance of the heat transfer member  260  is set to approximately 0.2 K/W. Here, the thermal path through the die attach member  150  has a cross-sectional area of Sd, a length of Ld, and a thermal conductivity of κd, the thermal path through the heat transfer member  260  has a cross-sectional area of Sn and a length of Ln, and the thermal conductivity of the nanocomposite making up the heat transfer member  260  is Kn. Thus, the relation of Math. 4, below, holds true. 
     
       
         
           
             
               
                 
                   
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     In the light-emitting module  2  pertaining to the present Embodiment, the cross-sectional area of the thermal path through the heat transfer member  260  is twice that of the thermal path through the die attach member  150 . Also, the length of the thermal path through the heat transfer member  260  is four times that of the thermal path through the die attach member  150 . Given these dimensions, and a die attach member  150  thermal conductivity κd of 0.15 W/m·K, then according to Math. 4, the thermal conductivity κn required for the nanocomposite making up the heat transfer member  260  is 2.7 W/m·K. 
     Thus, according to the relation of Math. 3, when the base material of the nanocomposite is silicone resin and the nanocomposite has a thermal conductivity κn of 2.7 W/m·K, the nanoparticle volume fraction is approximately 60% for nanoparticles made of ZnO or MgO, approximately 71% for nanoparticles made of TiO, and approximately 95% for nanoparticles made of ZrO 2 . Given the nanocomposite fragility considerations mentioned above, ZnO and MgO are beneficial materials for the nanoparticles. 
     Embodiment 3 
     The following describes a light-emitting module  1001  pertaining to the present Embodiment. Components identical to those of Embodiment 1 use the same reference signs thereas, and explanations thereof are omitted. 
       FIGS. 9A, 9B, and 9C  illustrate the light-emitting module pertaining to the present Embodiment.  FIG. 9A  shows a plan view,  FIG. 9B  shows a plan view of the area outlined by dashed line A 2  in  FIG. 9A  without the sealing member, and  FIG. 9C  shows a partial cross-section. 
     As shown, the light-emitting module  1001  includes a substrate  1110 , a plurality of LED chips  120 , a sealing member  1140 , and a plurality of heat transfer members  160  each arranged at an outer circumferential area of one of the LED chips  120 . 
     The substrate  1110  is a rectangular plate having a wiring pattern formed on one face thereof and having a frame  1118  formed at the approximate centre of the same face, the frame  1118  being annular in a plan view. The wiring pattern is made up of electrode pads  1130   a  for receiving power from an external power source, and land portions  1130   b  for electrically connecting two neighbouring LED chips  120 . The land portions  1130   b  are each disposed between two neighbouring LED chips  120  with respect to a column direction (i.e., the vertical direction in  FIG. 9A ) within the area encircled by the frame  1118  on the main surface of the substrate  1110 . The substrate  1110  is, for example, a plate made of aluminium or a similar metal material on which an insulating layer is formed from a ceramic substrate or a thermally conductive resin, thus producing a two-layer configuration. 
     As shown in  FIG. 9A , the LED chips  120  are arranged in a matrix pattern on the main surface of the substrate  1110 , such that a roughly circular pattern is formed by the whole. The LED chips  120  are not limited to being arranged as illustrated by  FIG. 9A . 
     The LED chips  120  and the heat transfer members  160  are covered by a sealing member  1140  disposed inside the frame  1118 . As shown in  FIGS. 9B and 9C , the land portions  1130   b  and electrodes arranged on top of the LED chips  120  are electrically connected via metal wires  1122 . A pair of neighbouring LED chips  120  is electrically connected by one of the land portions  1130   b  that is arranged at a position corresponding to the pair of LED chips  120  and by two metal wires  1122 . Also, the heat transfer members  160  are arranged such that the electrodes of the LED chips  120  and a portion of the land portions  1130   b  and metal wires  1122  forming the wiring pattern are not covered thereby. 
     The present Embodiment has been described in terms of an example in which the heat transfer member  160  includes the nanocomposite  162  and the microparticles  161  described in Embodiment 1. However, no limitation is intended, and the heat transfer member  160  may instead be replaced by the heat transfer member  260  that solely includes the nanocomposite, as described in Embodiment 2. 
     Embodiment 4 
     The following describes a light-emitting module having a lamp  100  pertaining to the present Embodiment. 
       FIG. 10A  shows a perspective view of the lamp  100 , and  FIG. 10B  shows a cross-sectional view of the lamp  100 . 
     As shown in  FIG. 10A , the lamp  100  includes a light-emitting module  1  that is a light source, a globe  10  that is optically transmissive, a base  30  that receives electric power, a stem  40 , a support member  50 , a case  60 , and a pair of leads  70   a  and  70   b . As shown in  FIG. 10B , the lamp  100  also includes a power source circuit  80  contained within the case  60 . 
     The light-emitting module  1  serves as the light source for the lamp  100 , and is disposed within the globe  10  as shown in  FIG. 10A . Specifically, the light-emitting module  1  is arranged at the approximate centre of the bulb portion of the globe  10 . As such, the light-emitting module  1  being arranged at the approximate centre of the bulb portion of the globe  10  enables the lamp  100  to achieve omnidirectional flux distribution that approaches that of a conventional incandescent light bulb using a filament coil. 
     Also, as shown in  FIG. 10B , the light-emitting module  1  receives electric power from the power source circuit  80 , supplied via the two leads  70   a  and  70   b . As shown in  FIG. 10B , respective ends of the two leads  70   a  and  70   b  are inserted into the through-holes  112  at each longitudinal end of the light-emitting module  1 , and are thus electrically connected to the wiring pattern  130  via solder  90 . 
     As shown in  FIG. 10A , the globe  10  is shaped so as to have an enclosed bulb at one end and an opening at the other end. That is, the globe  10  is shaped as an empty bulb having a portion that narrows with increasing distance from the centre of the bulb, the opening being formed at a position farthest from the centre of the bulb. The shape of the globe  10  pertaining to the present Embodiment is the same as that of the general A-type incandescent bulb (see Japanese Industrial Standard JIS C7710). The globe  10  is made of an optically transmissive material such as silica glass, which is transparent to visible light. 
     The globe  10  is not limited to being shaped as an A-type bulb. For example, the globe  10  may instead be shaped as a G-type bulb or an E-type bulb. Also, the globe  10  need not necessarily be colourless. For example, the silica may be treated with a scattering process by forming an opalescent scattering film thereon. Also, red, yellow, or some other colouring may be applied, or a pattern or image may be applied, or else a reflective film may be applied to the base more than the light source, as is the case for reflector bulbs. The material for the globe  10  need not necessarily be silica glass. Acrylic or a similar optically transmissive resin may also be used. 
     As shown in  FIG. 10B , the base  30  receives electric power supplied from a (non-diagrammed) external power source for the power source circuit  80 . The electric power received by the base  30  is then supplied to the power source circuit  80  via power lines  82   a  and  82   b.    
     As shown in  FIG. 10A , the base  30  is shaped as a bottomed cylinder having a male helix portion  32  for screwing the base  30  into the outer circumferential surface of a (non-diagrammed) socket in a light fixture. Also, as shown in  FIG. 10B , the inner circumferential surface of the base  30  has a female helix portion  34  for screwing in the case  60 . The base  30  is made of metal or a similar electrically conductive material. In the present Embodiment, the base  30  is an E26 Edison screw base. However, the base  30  is not limited to being an E26 Edison screw base, but may also be an E17 base or another type of base. Further, the base  30  need not necessarily be a screw-in base, but may instead be another type of base such as an insertion base. 
     The stem  40  supports the light-emitting module. As shown in  FIG. 10A , the stem  40  is generally baculiform, extending from the vicinity of the opening of the globe  10  toward the interior of the globe  10 . Also, as shown in  FIG. 10B , the stem  40  has an end portion  40   a , which is a longitudinal end thereof arranged within the globe  10 , having a flat portion  41   a  for mounting the light-emitting module  1 . A protrusion  41   b  protruding in the extension direction of the stem  40  is provided at the approximate centre of the flat portion  41   a . The light-emitting module  1  is fixed to the end portion  40   a  of the stem  40  such that the protrusion  41   b  is inserted into through-hole  114  of the substrate  110 . As such, a surface of the substrate  110  in the light-emitting module  1  opposite the face on which the substrate LED chips  120  are mounted is in contact with the flat portion  41   a  of the end portion  40   a  on the stem  40 . 
     The stem  40  is made of aluminium of a similar metal material having relatively high thermal conductivity. However, the stem  40  is not limited to being formed of metal, but may also be formed of ceramic or another material having relatively high thermal conductivity. Thus, the stem  40  is made of a material having relatively high thermal conductivity and as such, the heat produced by the light-emitting module  1  is easily transmitted through the stem  40  to the base  30  and the globe  10 . As a result, deterioration in light-emitting efficacy and diminution in longevity caused by temperature increases can be constrained for the LED chips  120 . 
     Also, another end portion  40   b  at the other longitudinal end of the stem  40  is generally shaped as a circular frustum. The other end portion  40   b  has formed therein two insertion holes  40   b   1  and  40   b   2  for inserting the leads  70   a  and  70   b  therein. 
     The substrate  110  of the light-emitting module  1  and the stem  40  are fixed using an adhesive (non-diagrammed) made of silicone resin. The adhesive may be, for example, made of a material having high thermal conductivity due to the dispersal of metal microparticles within the silicone resin. 
     As shown in  FIG. 10A , the support member  50  is arranged so as to block the opening of the globe  10 . The support member  50  is inserted into the case  60  and fixed. The stem  40  is, in turn, fixed to the end of the support member  50  that is arranged in the globe  10 . The support member  50  and the stem  40  are fixed in place using screws. The support member  50  is a generally circular disc having a circumferential surface that is in contact with the inner circumference of the case  60 . Also, a through-hole  52  is formed at the approximate centre of the support member  50  so as to pass the leads  70   a  and  70   b  therethrough. Then, as shown in  FIG. 10B , the leads  70   a  and  70   b  originating at the power source circuit  80  pass through the through-hole  52  in the support member  50  and through the insertion holes  40   b   1  and  40   b   2  in the other end  40   b  of the stem  40 , extending to the light-emitting module  1  and being electrically connected to the wiring pattern  130  of the light-emitting module  1 . 
     A step portion  52   a  is formed at the circumference of the support member  50 , and the edge of the opening of the globe  10  is in contact with the step portion  52   a . The support member  50 , the case  60 , and the edge of the opening of the globe  10  are affixed to the step portion  52   a  by introducing an adhesive into a gap formed between the step portion  52   a  and the inner wall of the case  60 . The support member  50  is formed of aluminium or another metal material. However, the support member  50  is not limited to being formed of metal, but may also be formed of ceramic or another material. The adhesive used for fixing the support member  50 , the case  60 , and the globe  10  is, for example, a silicone resin having metal microparticles dispersed throughout. 
     Given that the support member  50  is made of a material having high thermal conductivity, heat is transferred from the light-emitting module  1  to the stem  40  and is effectively transmitted to the support member  50 . Also, given that the support member  50  is connected to the globe  10 , the heat transferred to the support member  50  is further transferred to the globe  10  and dissipated to the atmosphere from the exterior surface of the globe  10 . As a result, deterioration in light-emitting efficacy and diminution in longevity caused by temperature increases can be constrained for the LED chips  120 . Further, given that the support member  50  is connected to the case  60 , the heat transferred to the support member  50  from the light-emitting module  1  is also dissipated to the atmosphere from the exterior surface of the case  60 . 
     The case  60  is made of a resin material that does not conduct electricity, and thus insulates the stem  40  and the base  30  while containing the power source circuit  80 . The non-conducting resin material is, for example, polybutylene terephtalate (hereinafter, PBT) that includes glass fibres. As shown in  FIG. 10B , the case  60  includes a main portion  61  that is cylindrical and is arranged near the stem  40 , and a base attach portion  62  that is also cylindrical, is continuous with the main portion  61 , and has the base  30  enmeshed therewith. 
     The main portion  61  has an inner diameter that is almost equal to the outer diameter of the support member  50 . The support member  50  is then fit into the main portion  61  and fixed, such that the inner circumferential surface of the main portion  61  is partially in contact with the circumferential surface of the support member  50 . Given that the outer surface of the main portion  61  is exposed to the atmosphere, the heat transferred to the case  60  is primarily dissipated therethrough. 
     The base attach portion  62  includes a male helix portion  64  that can be screwed into the female helix portion  34  formed on the inner circumferential surface of the base  30 . The base  30  is fit onto the base attach portion  62  by screwing the male helix portion  64  into the female helix portion  34  of the base  30 , such that the outer circumferential surface of the base attach portion  62  is in contact with the base  30 . The heat transferred to the case  60  is then transmitted through the base attach portion  62  to the base  30  and thus dissipated from the outer surface of the base  30 . 
     As shown in  FIG. 10B , the power source circuit  80  is a circuit supplying electric power to the light-emitting module  1 , and is contained within the case  60 . Specifically, the power source circuit  80  includes a plurality of circuit elements  80   a  and a circuit board  80   b  on which the circuit elements  80   a  are mounted. The power source circuit  80  converts the power received from the base  30  from alternating current to direct current and supplies the direct current to the light-emitting module  1  via the two leads  70   a  and  70   b.    
     Embodiment 5 
     The following describes a light-emitting module  1001  pertaining to Embodiment 3 having a lamp (hereinafter, lamp unit)  2001  pertaining to the present Embodiment. 
       FIG. 11  shows a perspective view of a lamp pertaining to the present Embodiment, and  FIG. 12  shows an exploded view of the lamp unit  2001 . 
     The lamp unit  2001  has the light-emitting module  1001  pertaining to Embodiment 1 mounted therein as a light source. In addition to the light-emitting module  1001 , the lamp unit  2001  also includes a base  2020 , a holder  2030 , a dressing cover  2040 , a cover  2050 , a cover press member  2060 , and a wiring member  2070 . 
     The base  2020  is a round plate having a mount portion  2021  at the centre of the top face thereof. The light-emitting module  1001  is mounted on the mount portion  2021 . A pair of screw holes  2022  are also provided on the top face of the base  2020  on each side of the mount portion  2021 , in order to screw in assembly screws  2035  that fix the holder  2030 . The periphery of the base  2020  has insertion holes  2023 , boss holes  2024 , and a notch  2025 . The respective roles of the insertion holes  2023 , the boss holes  2024 , and the notch  2025  are explained later. The base  2020  is, for example, made of a metal material such as aluminium die cast. 
     The holder  2030  is a bottomed cylinder having a round press plate  2031  and a circumferential wall  2032  that extends from the edge of the press plate  2031  toward the base  2020 . The press plate  2031  presses the light-emitting module  1001  into the mount portion  2021  and thus fixes the light-emitting module  1001  onto the base  2020 . 
     A window aperture  2033  is provided at the centre of the press plate  2031  to expose the sealing member  1140  of the light-emitting module  1001 . Openings  2034  are formed at the periphery of the press plate  2031  and are continuous with the window aperture  2033 . The openings  2034  are provided in order to prevent leads  2071  connected to the light-emitting module  1001  from interfering with the holder  2030 . Further, insertion holes  2036  are provided at the edge of the press plate  2031  in the holder  2030  at positions corresponding to the screw holes  2022  of the base  2020 , in order for the assembly screws  2035  to pass therethrough. The holder  2030  is affixed to the base  2020  by first sandwiching the light-emitting module  1001  between the base  2020  and the holder  2030  such that the sealing member  1140  of the light-emitting module  1001  is exposed through the window aperture  2033  in the holder  2030 . Then, the assembly screws  2035  are made to pass through the insertion holes  2036  from the opposite side of the base  2020  with respect to the press plate  2031 , and are screwed into the screw holes  2022  of the base  2020 . Accordingly, the holder  2030  is affixed to the base  2020 . 
     The dressing cover  2040  is annular and disposed between the holder  2030  and the cover  2050  so as to cover the leads  2071 , the assembly screws  2035 , and other components exposed through the openings  2034 . Another window aperture  2041  is provided at the centre of the dressing cover  2040  to expose the sealing member  1140  of the light-emitting module  1001 . The dressing cover  2040  is made of a non-transparent material, such as a white resin that is not transmissive. 
     The cover  2050  is approximately shaped as a dome having a main portion  2051  that covers the sealing member  1140 , and an outer flange  2052  extending from the edge of the main portion  2051  toward the exterior. The outer flange  2052  is fixed to the base  2020 . The cover  2050  is, for example, made of silicone resin, acrylic resin, glass, or some other optically transmissive material. Light radiating from the sealing member  1140  thus passes through the cover  2050  to the exterior of the lamp unit  2001 . 
     The cover press member  2060  is made of aluminium or a similar metal material, of a white resin that is not optically transmissive, or of a similarly non-transparent material. As such, the light radiating from the main portion  2051  of the cover  2050  is unobstructed in passing through the annular portion. The outer flange  2052  of the cover  2050  is fixed in place between the cover press member  2060  and the base  2020 . 
     The cover press member  2060  has columnar bosses  2061  protruding toward the base  2020 . A semicircular notch  2053  is provided in the outer flange  2052  of the cover  2050  at a position corresponding to each boss  2061  in order to exclude the bosses  2061 . Furthermore, the boss holes  2024  are provided at the edge of the base  2020  at positions corresponding to the bosses  2061 , in order to allow the bosses  2061  to pass therethrough. The cover press member  2060  is affixed to the base  2020  as follows. The bosses  2061  of the cover press member  2060  are made to pass through the boss holes  2024  of the base  2020 . Then, the tips of the bosses  2061  opposite the cover press member  2060  with respect to the base  2020  are then irradiated with a laser to cause elastic deformation, thus preventing the tips from escaping the boss holes  2024 . Accordingly, the cover press member  2060  is affixed to the base  2020 . 
     Semicircular notches  2054  and  2062  are respectively formed at positions corresponding to the insertion holes  2023  of the base  2020  in the outer flange  2052  of the cover  2050  and in the edge of the cover press member  2060 . Thus, (non-diagrammed) attachment screws are able to pass through the insertion holes  2023  without touching the cover press member  2060  or the cover  2050 . 
     The wiring member  2070  has a pair of leads  2071  that are electrically connected to the light-emitting module  1001 , and are attached to a connector  2072  at ends opposite the ends connected to the light-emitting module  1001 . The leads  2071  of the wiring member  2070  connected to the light-emitting module  1001  lead to the outside of the lamp unit  2001  via the notch  2025  of the base  2020 . 
     Embodiment 6 
       FIG. 13  shows a perspective view of a lighting apparatus  3001  pertaining to the present Embodiment. 
     The lighting apparatus  3001  is a downlight installed into a ceiling C, and includes a fixture  3003 , a circuit unit  3004 , a dimmer unit  3005 , and the lamp unit  2001  described in Embodiment 5. 
     The fixture  3003  includes a lamp container  3003   a , a circuit container  3003   b , and an outer flange  3003   c . The fixture  3003  is, for example, made of a metal material such as aluminium die cast. The lamp container  3003   a  is a bottomed cylinder that is removably mounted in the lamp unit  2001 . The circuit container  3003   b  extends from the bottom of the lamp container  3003   a  and contains the circuit unit  3004 . The outer flange  3003   c  is annular and extends outward from the opening of the lamp container  3003   a . The fixture  3003  is embedded in an embedding hole C 1  provided in the ceiling C for the lamp container  3003   a  and the circuit container  3003   b . The outer flange  3003   c  is affixed to the ceiling C using (non-diagrammed) attachment screws, for example, so as to be in contact with the edge of the embedding hole C 1  at the underface C 2  of the ceiling C. 
     The circuit unit  3004  has a power line  3004   a  electrically connected to the lamp unit  2001  in order to light the lamp unit  2001 . The tip of the power line  3004   a  is attached to a connector  3004   b  that is removably connected to the connector  2072  of the leads  2071  of the lamp unit  2001 . Although the lighting apparatus  3001  is described as having the lamp unit  2001  and the circuit unit  3004  as separate units, the circuits of the circuit unit  3004  may also be mounted within the lamp unit. 
     The dimmer unit  3005  is provided in order to allow the user to adjust the colour temperature of the light from the lamp unit  2001 . The dimmer unit  3005  is electrically connected to the circuit unit  3004 , receives user operations, and outputs a dimmer signal to the circuit unit  3004 . 
     In the present Embodiment, the lighting apparatus  3001  is described as having the lamp unit of Embodiment 5 mounted therein. However, the lighting apparatus pertaining to the present Embodiment is not limited in this manner, and may also, for example, have a lighting apparatus mounted therein that includes the lamp  100  of Embodiment 4. 
     (Variations) 
     (1) The light-emitting module  1  pertaining to Embodiment 1 is described in an example where the heat transfer member  160  is only in contact with the side walls of the LED chips  120 . However, no such limitation is intended. 
     For example, as shown in  FIG. 14A , a light-emitting module  3  may have a heat transfer member  360  that is disposed so as to cover the surface (i.e., top face) of the LED chips  120  opposite the face (i.e., bottom face) that is on the die attach member  150 , in addition to the side walls. Thus, the heat transfer member  360  is in contact with the top face of the LED chips  120 . 
     Also, the light-emitting module  1  pertaining to Embodiment 1 is described in an example where the heat transfer members  160  disposed at the outer circumferential area of a pair of neighbouring LED chips  120  are not in contact with one another. However, no such limitation is intended. For example, the heat transfer members  160  disposed at the outer circumferential areas of a pair of neighbouring LED chips  120  may be in contact. 
     Furthermore, as shown in  FIG. 14B , a light-emitting module  3   a  may be configured such that a heat transfer member  360   a  fills an area between the substrate  110  and the sealing member  140   a  in which the LED chips  120  and so on are disposed. 
     (2) The light-emitting module  1  pertaining to Embodiment 1 is described in an example where the die attach member  150  is made of a silicone resin adhesive. However, no such limitation is intended. 
     For example, as shown in  FIG. 15 , a light-emitting module  4  may have a die attach member  350  made from an adhesive that includes microparticles  351  and the nanocomposite  352 . 
     (3) The light-emitting module  1  pertaining to Embodiment 1 is described in an example where the sealing member  140  is provided so as to seal the LED chips  120  and the heat transfer member  160 . However, no such limitation is intended. 
     For example, as shown in  FIG. 16A , a light-emitting module  5  may have a hollow sealing member  440  where a gap is provided between the inner circumferential surface of the sealing member  440 , the LED chips  120 , and the heat transfer member  160 . 
     (4) The light-emitting module  1  pertaining to Embodiment 1 is described in an example where COB LED chips  120  are used. However, no such limitation is intended. 
     For example, as shown in  FIG. 16B , a light-emitting module  6  may use surface-mounted LEDs  520 . Such LEDs  520  each include a package  542  made of polycrystalline alumina (hereinafter, PCA) or a similar transparent material, the LED chips  120  mounted in the package  542  using an adhesive member such as solder, and a sealing member  540  sealing the interior of the package  542 . In such a case, as shown in  FIG. 16B , the side walls of the package  542  are in contact with the heat transfer member  560 , such that the heat transferred from the LED chips  120  to the package  542  is, in turn, transferred to the substrate  110  via the heat transfer member  560  and the die attach member  550 . That is, the main surface of the substrate  110  and the bottom faces of the LED chips  120  are thermally connected via the package  542  and the heat transfer member  560 . The heat transfer member  560  is made up of microparticles  561  and a nanocomposite  562 . 
     Also, as shown in  FIG. 17 , a light-emitting module  7  may be fixed in a package  842  by the die attach member  150  and the heat transfer member  160 , and the package  842  is sealed by a sealing member  840 . Here, the package  842  is fixed to the substrate  110  by an adhesive  750 . 
     (5) In Embodiment 3, the heat transfer member  160  is described as being arranged such that the electrodes of the LED chips  120  and a portion of the land portions  1130   b  and metal wires  1122  forming the wiring pattern are not covered thereby. However, no such limitation is intended. A portion of the heat transfer member may cover the aforementioned portion of the land portions  1130   b.    
       FIGS. 18A, 18B, and 19  each show cross-sections of variant light-emitting modules  8   a ,  8   b , and  8   c.    
     As shown in  FIG. 18A , a light-emitting module  8   a  may have the electrodes of the LED chips  120  uncovered by the heat transfer member  160   a  while the portion of the land portions  1130   b  are covered by the heat transfer member  160   a.    
     According to this configuration, the heat produced by the LED chips  120  is dissipated toward the substrate  1110  via the land portions  1130   b , which have good heat transfer properties. 
     As shown in  FIG. 18B , a light-emitting module  8   b  may have the electrodes of the LED chips  120  covered by the heat transfer member  160   b  while the portion of the land portions  1130   b  are not covered by the heat transfer member  160   b.    
     According to this configuration, the heat produced by the LED chips  120  is dissipated toward the substrate  1110  via the electrodes of the LED chips  120  themselves as well as the heat transfer member  160   b.    
     As shown in  FIG. 19 , a light-emitting module  8   c  may have a heat transfer member  160   c  cover the electrodes of the LED chips  120  and the portion of the land portions  1130   b . The heat transfer member  160   c  has a step portion  163   c  formed at the outer circumferential surface thereof. 
     According to this configuration, the heat produced by the LED chips  120  is dissipated toward the substrate  1110  via the land portions  1130   b , which have good heat transfer properties, and via the electrodes of the LED chips  120  themselves as well as the heat transfer member  160   c.    
     In addition, the manufacturing process for the light-emitting module pertaining to the present disclosure may include an additional step of heating the entirety of the substrate in order to apply thermal curing to the heat transfer member. Accordingly, the stress applied to the metal wires  1122  when thermal curing is applied to the heat transfer member increases with increasing proportion of components embedded within the heat transfer member, including the metal wires  1122 . 
     In contrast, the present configuration includes a step portion  163   c  provided in a part of the outer circumferential surface of the heat transfer member  160   c . This reduces the proportion of components embedded within the heat transfer member  160   c . As such, the stress applied to the metal wire  1122  during thermal curing of the heat transfer member  160   c  is decreased. This reduces the risk of problems such as breaking occurring in the metal wire  1122  during manufacturing. 
     (6) In Embodiment 3, the heat transfer member  160  is described in an example where the LED chips  120  are disposed so as to be individually surrounded. However, no such limitation is intended. 
     The light-emitting module  1002  pertaining to the present variation is shown with the sealing member  1140  partially removed, in a plan view in  FIG. 20A  and in a partial cross-section in  FIG. 20B . A full plan view of the light-emitting module  1002  is shown in  FIG. 9A  and has previously been described in Embodiment 3. Components identical to those of Embodiment 3 use the same reference signs thereas, and explanations thereof are omitted. 
     The light-emitting module  1002  has a heat transfer member  460  filling the area between the substrate  1110  and the sealing member  1140  where the LED chips  120  and so on are disposed. Accordingly, the heat transfer member  460  suffices to entirely cover the outer circumferential area of each LED chip  120  on the substrate  110  and the top face of all the LED chips  120 . 
     According to this configuration, the heat produced by the LED chips  120  is dissipated toward the substrate  1110  via the land portions  1130   b , which have good heat transfer properties, and via the electrodes of the LED chips  120  themselves as well as the heat transfer member  460 . 
     Also, according to this configuration, the material (i.e., the liquid mixture of nanocomposite and microparticles) used as the base for the heat transfer member  460  may be simply applied to the entirety of the region where the LED chips  120  are disposed on the substrate  1110 . As such, the configuration is simplified relative to that of the light-emitting module  1001  described in Embodiment 3. 
     Further,  FIGS. 21A and 21B  illustrate an alternate configuration pertaining to the present variation for light-emitting modules  1003 ,  1004 , and  1005 . A full plan view of the light-emitting modules  1003 ,  1004 , and  1005  is shown in  FIG. 9A  and has previously been described in Embodiment 3. Components identical to those of Embodiment 3 use the same reference signs thereas, and explanations thereof are omitted. 
     As shown in  FIG. 21A , the light-emitting module  1003  has a heat transfer member  660  that is formed into bands and disposed on the main surface of the substrate  1110  in a region that includes the entire outer circumferential area of each LED chip  120  aligned horizontally, and also covers the top face of the same LED chips  120 . In other words, the heat transfer member  660  entirely covers the outer circumferential area and the top face of the LED chips  120  that are disposed in a horizontal unit. 
     Accordingly, the heat transfer member  660  is arranged so as to cover the electrodes of the LED chips  120  while not covering the land portions  130   b.    
     According to this configuration, the material (i.e., the liquid mixture of nanocomposite and microparticles) used as the base for the heat transfer member  660  may be simply applied in bands to the region where the LED chips  120  are disposed on the substrate  1110 . As such, the configuration is simplified relative to that of the light-emitting module  1001  described in Embodiment 3, in which application is performed on the LED chips  120  individually. 
     Also, according to this configuration, the heat produced by the LED chips  120  is additionally dissipated through the heat transfer member  160   b  toward the substrate  1110 , and corresponding improvements to heat transfer characteristics are provided that constrain light efficacy diminution in the LED chips  120 . 
     Furthermore, according to this configuration, the proportion of the metal wire  1122  embedded in the heat transfer member  660  is reduced in contrast to  FIGS. 20A and 20B . As such, with respect to the light-emitting module  1003  manufacturing process, the stress applied to the metal wire  1122  during thermal curing of the heat transfer member  660  is decreased. This reduces the risk of problems such as breaking occurring in the metal wire  1122  during manufacturing. 
     As shown in  FIG. 21B , the light-emitting module  1004  is configured almost identically to that shown in  FIG. 21A . However, a point of difference from  FIG. 21A  exists in that the heat transfer member  760  covers the land portions  130   b  while leaving the electrodes of the LED chips  120  uncovered. As such, the heat transfer member  760  is disposed in band regions that extend along the alignment direction of a pair of neighbouring LED chips  120  with respect to the vertical direction. 
     According to this configuration, the material (i.e., the liquid mixture of nanocomposite and microparticles) used as the base for the heat transfer member  760  may be simply applied in bands to the region where the LED chips  120  are disposed on the substrate  1110 . As such, the configuration is simplified in comparison to that of the light-emitting module  1001  described in Embodiment 3. 
     Also, according to this configuration, the heat produced by the LED chips  120  is dissipated through the land portions  1130   b , which have good heat transfer properties, toward the substrate  1110 , and corresponding improvements to heat transfer characteristics are provided that constrain light efficacy diminution in the LED chips  120 . 
     Furthermore, according to this configuration, the proportion of the metal wire  1122  embedded in the heat transfer member  760  is reduced in contrast to  FIGS. 20A and 20B . As such, with respect to the light-emitting module  1003  manufacturing process, the stress applied to the metal wire  1122  during thermal curing of the heat transfer member  760  is decreased. This reduces the risk of problems such as breaking occurring in the metal wire  1122  during manufacturing. 
     As shown in  FIG. 21C , a light-emitting module  1005  has a heat transfer member  860  disposed on the main surface of the substrate  1110  so as to include part of an outer circumferential area positioned at both sides of each row of semiconductor light-emitting elements aligned in a vertical direction, and so as to extend vertically in bands. Also, the heat transfer members  860  are arranged such that the electrodes of the LED chips  120 , the land portions  130   b , and the metal wires  1122  forming the wiring pattern are not covered thereby. 
     According to this configuration, the material (i.e., the liquid mixture of nanocomposite and microparticles) used as the base for the heat transfer member  860  may be simply applied in bands to the region where the LED chips  120  are disposed on the substrate  1110 . As such, the configuration is simplified relative to that of the light-emitting module  1001  described in Embodiment 3, in which application is performed on the LED chips  120  individually. 
     Also, unlike  FIGS. 20A, 20B, 21A, and 21B , the present configuration has the metal wires  1122  remain uncovered by the heat transfer member  860 . Accordingly, during the light-emitting module  1003  manufacturing process, the thermal shrinkage of the heat transfer member  860  during thermal curing does not affect the metal wires  1122 . Thus, the risk of breakage or other damage to the metal wires  1122  during manufacturing is further constrained. 
     (7) In Embodiment 4, an example is described of a lamp  100  using a light-emitting module  1  having a sealing member  140  that serves as a wavelength conversion member. However, no such limitation is intended. For example, as shown in  FIG. 22 , a light-emitting module  7  having a sealing member  740  that does not include fluorescent particles may be used, and the lamp  102  may be provided with a wavelength conversion member  12  that includes fluorescent particles and is disposed at the inner circumferential surface of the globe  10 .  FIG. 22  uses the same basic configuration and the same reference signs as Embodiment 3.
 
(8) The respective light-emitting modules  1 ,  2 , and  1001  described in Embodiments 1, 2, and 3 are all described in examples where the sealing member includes fluorescent particles and thus functions as a wavelength conversion member. However, no such limitation is intended. The sealing member need not necessarily include fluorescent particles. According to this configuration, the sealing member does not serve as a wavelength conversion member and the light radiating from the LED chips is radiated out through the sealing member without undergoing wavelength conversion therein.
 
     LIST OF REFERENCE SIGNS 
     
         
           1 ,  2 ,  3 ,  4 ,  5 ,  6 ,  7  Light-emitting module 
           10  Globe 
           12  Wavelength conversion member 
           30  Base 
           40  Heat sink 
           50  Support member 
           60  Case 
           70   a ,  70   b  Leads 
           80  Power source circuit 
           82   a ,  82   b  Power lines 
           100 ,  102  Lamp 
           110  Substrate 
           112 ,  114  Through-holes 
           120  LED chips 
           122 ,  124  Metal wire 
           130  Wiring pattern 
           130   a  Land portions 
           130   b  Leg parts 
           140 ,  640  Sealing member 
           150  Die attach member 
           160  Heat transfer member 
           161 ,  351  Microparticles 
           162  Nanocomposite