Patent Publication Number: US-2015084077-A1

Title: Light Emitting Module and Lighting Device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priorities from Japanese Patent Application No. 2013-196177 filed on Sep. 20, 2013; the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to a light emitting module and a lighting device. 
     BACKGROUND 
     In recent years, a lighting device of which a light source is a Light Emitting Diode (LED) is widespread. As the LED that is used in such a lighting device, for example, an LED having a structure is known in which a semiconductor layer (a light emitting layer) including GaN or the like is provided on a transparent base material such as sapphire and the semiconductor layer is covered by a resin including the phosphor. In the LED having such a structure, the light that is emitted from a surface of a side of the base material of the light emitting layer is emitted to the outside of the LED through the transparent base material. 
     However, in the LED, heat is generated as light is emitted. Since decrease in an amount of the light or deterioration of the resin occurs if a temperature of the LED increases, it is necessary to suppress the increase in the temperature of the LED. However, in the LED of the related art, if the periphery of the base material is covered by a heat radiating member, the light transmitting the base material is blocked and luminous efficiency is lowered. Thus, it is difficult to suppress the increase in the temperature of the LED. 
     Further, recent years, the LED in which a black material such as silicon is used in the base material is also developed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating an example of a lighting device according to a first embodiment. 
         FIG. 2  is a cross-sectional view of an example of the lighting device according to the first embodiment. 
         FIG. 3  is a conceptual view illustrating an example of an electrical connection relationship of the lighting device according to the first embodiment. 
         FIG. 4  is a view illustrating an example of a configuration of a light emitting unit according to the first embodiment. 
         FIG. 5  is a top view illustrating an example of a light emitting module according to the first embodiment. 
         FIG. 6  is a cross-sectional view of the light emitting module along A-A in  FIG. 5 . 
         FIG. 7  is an enlarged view of the vicinity of an LED in  FIG. 6 . 
         FIG. 8  is a top view illustrating an example of a light emitting module according to a second embodiment. 
         FIG. 9  is a cross-sectional view of the light emitting module along B-B in  FIG. 8 . 
         FIG. 10  is an enlarged view of the vicinity of an LED in  FIG. 9 . 
         FIG. 11  is a top view illustrating an example of a light emitting module according to a third embodiment. 
         FIG. 12  is a cross-sectional view of the light emitting module along C-C in  FIG. 11 . 
         FIG. 13  is a cross-sectional view illustrating an example of a light emitting module according to a fourth embodiment. 
         FIG. 14  is a view illustrating an example of the vicinity of an LED according to a fifth embodiment. 
         FIG. 15  is a view illustrating an example of the vicinity of an LED according to a sixth embodiment. 
         FIG. 16  is a view illustrating an example of the vicinity of an LED according to a seventh embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In view of the problems of the related art, it is an object of the present invention to suppress increase in the temperature of the LED. 
     According to an embodiment described below, a light emitting module includes: an LED that is an example of a semiconductor light emitting element configured to include a base material that is formed of a material absorbing light and is provided on a substrate, and a light emitting layer that is provided on the base material and emits the light; and a heat radiating section configured to be provided in a periphery of the base material and radiate heat generated in the light emitting layer to the substrate by receiving the heat through the base material. According to the configuration, it is possible to expect that increase in the temperature of the LED is suppressed. 
     Further, in the light emitting module according to the embodiment described below, it is preferable that the heat radiating section be connected to the base material on two or more surfaces besides a surface on which the light emitting layer is provided in the base material. Therefore, it is possible to expect that the heat generated in the light emitting layer is efficiently transferred to the heat radiating section through the base material. 
     Further, in the light emitting module according to the embodiment described below, the base material may be formed in a six-sided shape; and the heat radiating section may be connected to four surfaces besides a surface on which the light emitting layer is provided and a surface on the side opposite the surface on which the light emitting layer is provided in the base material. Therefore, it is possible to expect that the heat generated in the light emitting layer is efficiently transferred to the heat radiating section through the base material. 
     Further, in the light emitting module according to the embodiment described below, the heat radiating section may be adhesive bonding the base material to the substrate, and a thermal conductivity of the adhesive may be 0.3 W/mK or greater. Therefore, it is possible to expect that the adhesive efficiently radiates the heat that is transferred from the base material to the substrate. 
     Further, in the light emitting module according to the embodiment described below, the adhesive may cover an area of half or more of side surfaces of the base material. Therefore, it is possible to expect that the heat generated in the light emitting layer is efficiently transferred to the adhesive through the base material. 
     Further, in the light emitting module according to the embodiment described below, in a state where the adhesive bonds the base material and the substrate, a length of the adhesive around the base material in a thickness direction of the substrate may be greater than a length that is obtained by adding a thickness of the base material and a thickness of the light emitting layer. Therefore, it is possible to suppress the increase in the temperature of the LED and it is possible to expect that light distribution of an entirety of the LED is controlled by a smaller device. 
     Further, in the light emitting module according to the embodiment described below, the heat radiating section may be a substrate configured to have a concave section into which the base material is fitted. Therefore, it is possible to expect that the increase in the temperature of the LED is efficiently suppressed in a small space. 
     Further, in the light emitting module according to the embodiment described below, it is preferable that a length of the concave section in the thickness direction of the substrate be longer than a length of half of the thickness of the base material. Therefore, it is possible to expect that the heat that is generated in the light emitting layer is efficiently transferred to the substrate through the base material. 
     Further, in the light emitting module according to the embodiment described below, the length of the concave section in the thickness direction of the substrate may be longer than the length that is obtained by adding the thickness of the base material and the thickness of the light emitting layer. Therefore, it is possible to suppress the increase in the temperature of the LED and to expect that the light distribution of the entirety of the LED is controlled by a smaller device. 
     Further, in the light emitting module according to the embodiment described below, the base material may have silicon. Further, a lighting device according to an embodiment described below may include the light emitting module described above and a lighting-on device configured to supply electric power to the light emitting module. 
     Hereinafter, the light emitting module and the lighting device according to the embodiments are described with reference to the drawings. Moreover, in the embodiments, the same reference numerals are given to configurations having the same functions and duplicate descriptions are omitted. Further, the light emitting module and the lighting device described in the embodiments below are illustrated as only an example and do not limit exemplary embodiments. Further, the embodiments described below may be appropriately combined within a range that is not inconsistent. 
     First Embodiment 
     Hereinafter, a straight tube type lamp and a lighting device including the straight tube type lamp of a first embodiment, for example, a lighting apparatus, are described with reference to  FIGS. 1 to 6 . 
     Configuration of Lighting Device  1   
       FIG. 1  is a perspective view illustrating an example of the lighting device according to the first embodiment.  FIG. 2  is a cross-sectional view of the lighting apparatus illustrated in  FIG. 1 . In  FIGS. 1 and 2 , a numeral  1  illustrates a direct-mounted type lighting device. 
     The lighting device  1  includes a device body (an apparatus body)  2 , a lighting-on device  3 , a pair of first socket  4   a  and second socket  4   b , a reflection member  5 , a straight tube type lamp  11  that is an example of a light source device and the like. 
     The body  2  illustrated in  FIG. 2  is, for example, made of a metal plate having an elongated shape. The body  2  extends in a front and back direction of a paper on which  FIG. 2  is drawn. The body  2  is, for example, fixed to a ceiling in a room by using a plurality of screws (not illustrated). 
     The lighting-on device  3  is fixed to a middle section of the body  2  in a longitudinal direction. The lighting-on device  3  generates a DC output by receiving a commercial AC power supply and supplies the DC output to the straight tube type lamp  11  described below. 
     Moreover, the body  2  has a power supply terminal stand (not illustrated), a plurality of member support fittings, a pair of socket support members, and the like. A power supply line of the commercial AC power supply drawn from the ceiling is connected to the power supply terminal stand. Further, the power supply terminal stand is electrically connected to the lighting-on device  3  through a wiring (not illustrated) in the apparatus. 
     The socket  4   a  and the socket  4   b  are disposed in both end sections of the body  2  in the longitudinal direction by being respectively connected to the socket support members. The socket  4   a  and the socket  4   b  are mounted by rotation. For example, the socket  4   a  and the socket  4   b  are sockets suitable for G13 type mouthpieces  13   a  and  13   b , respectively, which are included in the straight tube type lamp  11  described below. 
       FIG. 3  is a conceptual view illustrating an example of an electrical connection relationship of the lighting device according to the first embodiment. As illustrated in  FIG. 3 , the socket  4   a  and the socket  4   b  have a pair of terminal fittings  8  and terminal fittings  9  to which lamp pins  16   a  and  16   b  (described below) are respectively connected. In order to supply the power supply to the straight tube type lamp  11  described below, the terminal fittings  8  of the first socket  4   a  are connected to the lighting-on device  3  through the wiring in the apparatus. 
     As illustrated in  FIG. 2 , for example, the reflection member  5  has a bottom plate section  5   a , a side plate section  5   b  and an end plate  5   c  which are made of a metal, and has a trough shape of which an upper surface is opened. The bottom plate section  5   a  is flat. The side plate section  5   b  is bent obliquely upward from the both ends of the bottom plate section  5   a  in a width direction. The end plate  5   c  closes an end surface opening formed by ends of the bottom plate section  5   a  and the side plate section  5   b  in the longitudinal direction. 
     A metal plate forming the bottom plate section  5   a  and the side plate section  5   b  is made of a color steel plate of which a surface has a white-based color. Thus, the surfaces of the bottom plate section  5   a  and the side plate section  5   b  are reflection surfaces. Socket holes (not illustrated) are formed on respective ends of the bottom plate section  5   a  in the longitudinal direction. 
     The reflection member  5  covers the body  2  and each component that is mounted on the body  2 . The state is held by detachable decorative screws  6  (see  FIG. 1 ). The decorative screw  6  is screwed upwardly into the member support fitting through the bottom plate section  5   a . The decorative screw  6  may be operated by hand without using any tool. The socket  4   a  and the socket  4   b  protrude downward from the bottom plate section  5   a  through the socket holes. 
     In  FIG. 1 , the lighting device  1  supports one straight tube type lamp  11  described below, but, for example, may include two pairs of sockets to support two straight tube type lamps  11  as another form. 
     The straight tube type lamp  11  that is detachably supported by the socket  4   a  and the socket  4   b  is described below with reference to  FIGS. 2 and 3 . The straight tube type lamp  11  has dimensions and an outer diameter similar to those of the existing fluorescent lamp. The straight tube type lamp  11  includes a pipe  12 , a first mouthpiece  13   a  and second mouthpiece  13   b  which are mounted in both ends of the pipe  12 , a beam  14  and a light emitting unit  15 . 
     The pipe  12  is formed of a resin material having translucency, for example, in an elongated shape. As the resin material forming the pipe  12 , a polycarbonate resin in which a light diffusion member is mixed can be preferably used. Diffuse transmittance of the pipe  12  is preferably 90% to 95%. As illustrated in  FIG. 2 , the pipe  12  has a pair of convex sections  12   a  on an inner surface of a portion that is an upper section when being used. 
     The first mouthpiece  13   a  is mounted on one end section of the pipe  12  in the longitudinal direction and the second mouthpiece  13   b  is mounted on the other end section of the pipe  12  in the longitudinal direction. The first mouthpiece  13   a  and second mouthpiece  13   b  are detachably connected to the socket  4   a  and the socket  4   b , respectively. The straight tube type lamp  11  that is supported on the socket  4   a  and the socket  4   b  is disposed directly below the bottom plate section  5   a  of the reflection member  5  by the connection. A part of light that is emitted from the straight tube type lamp  11  to the outside is reflected from the side plate section  5   b  of the reflection member  5 . 
     As illustrated in  FIG. 3 , the first mouthpiece  13   a  has two lamp pins  16   a  protruding to the outside thereof. The lamp pins  16   a  are electrically insulated from each other. In addition, leading ends of the two lamp pins  16   a  have L-shapes which are bent substantially at a right angle so as to separate from each other. 
     As illustrated in  FIG. 3 , the second mouthpiece  13   b  has one lamp pin  16   b  protruding to the outside thereof. The lamp pin  16   b  has a cylindrical shaft section and a leading end section which is provided in a leading end section of the cylindrical shaft section, and of which a shape of a front surface (not illustrated) has an elliptical shape or an oval shape, and a side surface of the lamp pin  16   b  has a T-shape. 
     The lamp pins  16   a  of the first mouthpiece  13   a  are connected to the terminal fittings  8  of the socket  4   a  and the lamp pin  16   b  of the second mouthpiece  13   b  is connected to the terminal fittings  9  of the socket  4   b  so that the straight tube type lamp  11  is mechanically supported on the socket  4   a  and the socket  4   b . In a state of being supported, power is supplied to the straight tube type lamp  11  by the terminal fittings  8  inside the socket  4   a  and the lamp pins  16   a  of the first mouthpiece  13   a  connected thereto. 
     As illustrated in  FIG. 2 , the beam  14  is accommodated in the pipe  12 . The beam  14  is a bar member having excellent mechanical strength and, for example, is formed of an aluminum alloy or the like for weight reduction. Both ends of the beam  14  in the longitudinal direction are connected to the first mouthpiece  13   a  and the second mouthpiece  13   b  by being electrically insulated. For example, the beam  14  has a plurality of substrate support sections  14   a  (one is illustrated in  FIG. 2 ) having rib shapes. 
       FIG. 4  is a view illustrating an example of a configuration of the light emitting unit according to the first embodiment. As illustrated in  FIG. 4 , in the light emitting unit  15 , a plurality of light emitting modules  54  are arranged on a substrate  21  in the longitudinal direction of the substrate  21 , which is formed in an elongated substantially rectangular shape. Various electric components  57  to  59  such as a capacitor or a connector are disposed on the substrate  21 . A surface of the substrate  21  has a resist layer mainly composed of a synthetic resin having high electric insulation. The resist layer is, for example, white and also functions as a reflective layer having high reflectance of light. 
     A length of the substrate  21  is substantially the same as an entire length of the beam  14 . The substrate  21  is fixed by screws (not illustrated) which are screwed into the beam  14 . In the embodiment, the light emitting unit  15  has one substrate  21 , but the light emitting unit  15  may be configured of a plurality of substrates as another form. 
     The light emitting unit  15  and the beam  14  are accommodated in the pipe  12 . In the state of being supported, both end sections of the light emitting unit  15  in the width direction are installed in the convex sections  12   a  of the pipe  12 . Therefore, the light emitting unit  15  is disposed substantially horizontally on an upper side from the maximum width section inside the pipe  12 . 
     Configuration of Light Emitting Module  54   
       FIG. 5  is a top view illustrating an example of the light emitting module according to the first embodiment.  FIG. 6  is a cross-sectional view of the light emitting module along A-A in  FIG. 5 .  FIG. 7  is an enlarged view of the vicinity of an LED in  FIG. 6 . 
     The light emitting module  54  has an LED  45  and a sealing member  53 . The LED  45  has a base material  44  that is formed of silicon or a material containing silicon and a semiconductor layer (a light emitting layer)  43  that is formed on the base material  44  and contains gallium nitride (GaN) or the like. In the embodiment, for example, the base material  44  is formed in a six-sided shape. The base material  44  is bonded on a second wiring pad  27  by adhesive  30 . In the embodiment, the adhesive  30  is configured of a material having high reflectance (for example, the reflectance is 60% or greater) such as that with a white or silver color. 
     An anode electrode and a cathode electrode are formed in the light emitting layer  43 . The anode electrode of the light emitting layer  43  is wire-bonded to a first wiring pad  26  by a metal wire  51  such as gold. Further, the cathode electrode of the light emitting layer  43  is wire-bonded to the second wiring pad  27  by a metal wire  52  such as gold. For example, surfaces of the first wiring pad  26  and the second wiring pad  27  are plated with a material having high reflectance such as silver. 
     For example, the sealing member  53  is a transparent thermoplastic resin having high diffusion, such as an epoxy resin, a urea resin, and a silicon resin, to which phosphors  31  are added. The phosphor  31  is excited by the light emitted from the light emitting layer  43  of the LED  45  and then radiates the light of a color that is different from a color of the light emitted from the light emitting layer  43 . 
     In the embodiment, as the phosphor  31 , an yellow phosphor is used which radiates yellow-based light that has a complementary color to blue light by being excited by the blue light emitted from the light emitting layer  43 . Therefore, the light emitting module  54  can emit white light as output light. 
     In the embodiment, since the base material  44  is formed of silicon, a surface of the base material  44  is black and absorbs the light. Thus, the light among the light emitted from the light emitting layer  43 , which is emitted from the surface of the light emitting layer  43  in contact with the base material  44 , is absorbed by the base material  44  and is not emitted to the outside. Therefore, the light emitting layer  43  mainly emits the light above the base material  44 . 
     Here, since the base material  44  is black and absorbs the light, when the base material  44  is exposed to the inside of the sealing member  53 , if the light from the light emitting layer  43  is incident on a direction of the base material  44  by being reflected from a boundary surface of the sealing member  53  or if a part of the light that is emitted from the phosphor  31  by receiving the light from the light emitting layer  43  is incident on the direction of the base material  44 , the base material  44  absorbs each light. 
     If a part of the light emitted from the light emitting layer  43  is absorbed by the base material  44 , the light is not emitted to the outside of the sealing member  53  and luminous efficiency of the light emitting module  54  is lowered. Therefore, in order to reduce an amount of the light incident on the base material  44 , it is preferable that an area of a surface in which the base material  44  is exposed to the inside of the light emitting module  54  be reduced in terms of improvement in the luminous efficiency. 
     In the embodiment, for example, as illustrated in  FIGS. 5 to 7 , the adhesive  30  covers two surfaces or more (in the embodiment, a total five surfaces of a bottom surface and side surfaces of the base material  44 ) of the base material  44  besides a surface on which the light emitting layer  43  is provided. For example, as illustrated in  FIGS. 5 to 7 , the adhesive  30  covers an area of half or more for each of the five surfaces of the base material  44  besides the surface on which the light emitting layer  43  is provided. 
     The adhesive  30  is configured of a material that is not transparent. Thus, the adhesive  30  prevents (suppresses) the light among the light from the light emitting layer  43 , which is reflected from the boundary surface of the sealing member  53  or prevents a part of the light which is emitted from the phosphor  31  by receiving the light from the light emitting layer  43 , from being incident on the base material  44 . Therefore, the adhesive  30  can reduce the amount of the light among the light emitted from the light emitting layer  43 , which is absorbed by the base material  44 . Therefore, it is possible to expect improvement in the luminous efficiency of the LED  45 . 
     Moreover, in the LED  45  according to the embodiment, since silicon is used in the base material  44 , the light emitted from a lower surface of the light emitting layer  43  is not emitted to the outside by being absorbed by the base material  44 . Thus, the adhesive  30  covering the bottom surface and the side surfaces of the base material  44  does not affect the luminous efficiency of the LED  45 , even if a material without translucency is used. 
     Further, in the embodiment, since the adhesive  30  is not necessary transparent, for example, a material having high reflectance such as alumina or titania can be added to the adhesive  30 . Since the adhesive  30  has high reflectance, the light incident on the direction of the base material  44  is reflected from the surface of the adhesive  30  and is emitted to the outside of the light emitting module  54 . Therefore, it is possible to expect the improvement in the luminous efficiency of the light emitting module  54 . 
     Moreover, the surfaces of the first wiring pad  26  and the second wiring pad  27  are plated with a material having high reflectance such as silver, and a white resist layer having high reflectance is provided on the surface of the substrate  21 . Thus, the light that is scattered in the sealing member  53  is also emitted to the outside of the light emitting module  54  by being reflected from those regions inside the light emitting module  54 . 
     Further, since the adhesive  30  may not be transparent, a material that improves the thermal conductivity in addition to the reflectance can be added to the adhesive  30 . The adhesive  30  is into contact with the base material  44  so as to cover the five surfaces besides the surface on which the light emitting layer  43  is provided. Thus, for example, as illustrated by arrows in  FIG. 7 , heat that is generated by the light emitting layer  43  and transferred to the base material  44  is respectively transferred to the adhesive  30  from four side surfaces as well as from the bottom surface of the base material  44 . Then, for example, as illustrated by the arrows in  FIG. 7 , the heat that is transferred from the base material  44  to the adhesive  30  is efficiently radiated to the substrate  21 . 
     Here, in the LED of the related art in which the base material is formed of a transparent material such as sapphire, the light that is emitted from the bottom surface of the light emitting layer  43  is emitted to the outside of the LED  45  by passing through the transparent base material. Thus, since the adhesive bonding the base material to the second wiring pad  27  shields the light passing through the base material, the adhesive cannot widely cover the side surfaces of the base material. 
     On the other hand, in the LED  45  according to the embodiment, since a black member that is not transparent such as silicon is used in the base material  44 , even if the adhesive  30  that is not transparent widely covers the side surfaces of the base material  44 , the adhesive  30  does not affect the luminous efficiency of the LED  45 . Thus, the adhesive  30  can widely cover the side surfaces of the base material  44 . Therefore, the heat that is generated by the light emitting layer  43  and transferred to the base material  44  is efficiently transferred to the adhesive  30 . Then, the adhesive  30  efficiently transfers the heat that is generated in the LED  45  to the substrate  21  through the second wiring pad  27  by employing the material having high thermal conductivity in the adhesive  30 . 
     Further, since the adhesive  30  may not be transparent, for example, there is no need to consider the translucency of the light for the adhesive  30  and a material having high reflectance and high thermal conductivity such as alumina or titania can be added to the adhesive  30 . Moreover, in the embodiment, it is preferable that the thermal conductivity of the adhesive  30  be 0.3 W/mK or greater. 
     Moreover, in the light emitting module  54  according to the embodiment, the adhesive  30  covers the five surfaces besides the surface on which the light emitting layer  43  is provided in the base material  44 , but the example is not limited to the embodiment and the adhesive  30  may cover half or more of one surface, two surfaces or three surfaces in the side surfaces of the base material  44 . Also, in this case, since the adhesive  30  having high thermal conductivity can widely cover the side surfaces of the base material, the heat that is generated in the LED  45  can be efficiently transferred to the substrate  21  through the adhesive  30  compared to the LED of the related art in which a transparent material is used in the base material. 
     The first embodiment is described above. 
     As is apparent from the above description, according to the light emitting module  54  of the embodiment, it is possible to expect the improvement in the luminous efficiency of the light emitting module  54 . Further, according to the light emitting module  54  of the embodiment, it is possible to expect that the heat that is generated in the LED  45  is efficiently radiated to the substrate  21 . 
     Second Embodiment 
     Next, a second embodiment is described with reference to the drawings. In the embodiment, since the configurations of a lighting device  1 , a straight tube type lamp  11  and a light emitting unit  15  are similar to the lighting device  1 , the straight tube type lamp  11  and the light emitting unit  15  of the first embodiment, detailed description thereof is omitted. 
     Configuration of Light Emitting Module  54   
       FIG. 8  is a top view illustrating an example of a light emitting module according to the second embodiment.  FIG. 9  is a cross-sectional view of the light emitting module along B-B in  FIG. 8 .  FIG. 10  is an enlarged view of the vicinity of an LED in  FIG. 9 . Moreover, since configurations to which the same symbols as those in  FIGS. 5 to 7  are given in  FIGS. 8 to 10  are the same as the configurations or have similar functions in  FIGS. 5 to 7 , the description thereof is omitted with exception that is described below. 
     A concave section  32  that has substantially the same shape as that of the base material  44  and is a recess that is slightly greater than an external shape of the base material  44  in a thickness direction of the substrate  21  is provided in the substrate  21 . The LED  45  is fitted into the concave section  32  as the light emitting layer  43  up and the bottom surface and the side surfaces of the base material  44  are bonded to a bottom and an inner wall of the concave section  32  with the adhesive  30 . Also in the embodiment, it is preferable that the adhesive  30  be configured of a material having high reflectance. 
     The anode electrode of the light emitting layer  43  is wire-bonded to the first wiring pad  26  by the metal wire  51  such as gold and the cathode electrode of the light emitting layer  43  is wire-bonded to a second wiring pad  29  by the metal wire  52  such as gold. For example, a surface of the second wiring pad  29  is also plated by a material having high reflectance such as silver. 
     In the embodiment, for example, as illustrated in  FIG. 10 , the concave section  32  is formed on the substrate  21  so that a length L 2  of the concave section  32  in the thickness direction of the substrate  21  is longer than a length of half of a thickness L 1  of the base material  44 . In the embodiment, the concave section  32  is formed on the substrate  21  so that the depth L 2  is substantially the same as a length that is obtained by adding the thickness L 1  of the base material  44  and the thickness of the adhesive  30  in contact with the bottom surface of the base material  44 . Therefore, the inner wall of the concave section  32  can further widely cover the side surfaces of the base material  44  through the adhesive  30  and the light that is emitted from the light emitting layer  43  is emitted into the sealing member  53  without being shielded by the inner wall of the concave section  32 . 
     Also in the embodiment, a resist layer having high reflectance is provided on the surface of the substrate  21 . Thus, the surface of the substrate  21  around the concave section  32  prevents (suppresses) the light that is reflected from the boundary surface of the sealing member  53  by being emitted from the light emitting layer  43  or prevents a part of the light that is emitted from the phosphor  31  by receiving the light from the light emitting layer  43  from being incident on the base material  44 . Therefore, the substrate  21  can reduce the amount of the light among the light emitted from the light emitting layer  43 , which is absorbed by the base material  44 . Therefore, it is possible to expect the improvement in the luminous efficiency of the LED  45 . 
     In the embodiment, for example, as illustrated in  FIGS. 8 to 10 , the inner wall of the concave section  32  covers two surfaces or more (in the embodiment, five surfaces) of the base material  44  besides a surface on which the light emitting layer  43  is provided. Further, for example, as illustrated in  FIGS. 8 to 10 , the inner wall of the concave section  32  covers an area of half or more of each of the five surfaces of the base material  44  besides the surface on which the light emitting layer  43  is provided. Therefore, the concave section  32  can reduce an area in which the side surfaces of the base material  44  are exposed to the inside of the sealing member  53  and it is possible to expect the improvement in the luminous efficiency of the LED  45 . 
     Further, in the embodiment, the adhesive  30  is configured of a material having high reflectance and the resist layer having high reflectance is provided on the surface of the substrate  21 . Thus, the light incident on the direction of the base material  44  is reflected from the surface of the adhesive  30  or the surface of the substrate  21  in the vicinity of the concave section  32 , and is emitted to the outside of the light emitting module  54 . Therefore, it is possible to expect the improvement in the luminous efficiency of the light emitting module  54 . 
     Further, the inner wall of the concave section  32  covers the five surfaces of the base material  44  besides the surface on which the light emitting layer  43  is provided, and the base material  44  and the concave section  32  are bonded with the adhesive  30  having high thermal conductivity. Thus, for example, as illustrated by arrows in  FIG. 10 , heat that is generated by the light emitting layer  43  and transferred to the base material  44  is respectively transferred to the adhesive  30  from four side surfaces of the base material  44  as well as from the bottom surface of the base material  44 . Then, for example, as illustrated by the arrows in  FIG. 10 , the heat that is transferred from the base material  44  to the adhesive  30  is efficiently radiated to the substrate  21  through the inner wall of the concave section  32 . 
     As described above, also in the embodiment, the heat that is generated by the light emitting layer  43  and transferred to the base material  44  is efficiently transferred to the adhesive  30  by widely covering the side surfaces of the base material  44  with the adhesive  30  and the inner wall of the concave section  32 . Then, it is possible to efficiently transfer the heat that is generated in the LED  45  to the substrate  21  through the inner wall of the concave section  32  by employing a material having high thermal conductivity in the adhesive  30 . 
     Moreover, in the light emitting module  54  according to the embodiment, the concave section  32  has substantially the same shape as that of the base material  44  in the thickness direction of the substrate  21  and has a shape slightly greater than the external shape of the base material  44 , but the example is not limited to the embodiment. For example, a groove that has a width substantially the same as the width of the base material  44  and has a depth of half or more of the thickness of the base material  44  is provided in the substrate  21  in the thickness direction of the substrate  21  and the LED  45  may be fitted into the groove as the light emitting layer up. Also in this case, it is possible to efficiently transfer the heat that is generated in the light emitting layer  43  from the inner wall of the groove in contact with the side surfaces of the base material  44  to the substrate  21  through the adhesive  30 . 
     The second embodiment is described above. 
     As is apparent from the above description, also in the light emitting module  54  of the embodiment, it is possible to expect the improvement in the luminous efficiency of the light emitting module  54 . Further, also in the light emitting module  54  of the embodiment, it is possible to expect that the heat that is generated in the LED  45  is efficiently radiated to the substrate  21 . 
     Third Embodiment 
     Next, a third embodiment is described with reference to the drawings. In the embodiment, since the configurations of a lighting device  1 , a straight tube type lamp  11  and a light emitting unit  15  are similar to the lighting device  1 , the straight tube type lamp  11  and the light emitting unit  15  of the first embodiment, detailed description thereof is omitted. 
     Configuration of Light Emitting Module  54   
       FIG. 11  is a top view illustrating an example of a light emitting module according to the third embodiment.  FIG. 12  is a cross-sectional view of the light emitting module along C-C in  FIG. 11 . Moreover, since configurations to which the same symbols as those in  FIGS. 5 and 6  are given in  FIGS. 11 and 12  are the same as the configurations or have similar functions in  FIGS. 5 and 6 , the description thereof is omitted with exception that is described below. 
     Four structures  33   a  to  33   d , which are formed of a material having high thermal conductivity and have substantially the same thickness as that of the base material  44 , are provided around the LED  45  so as to surround the LED  45  on the second wiring pad  27 . One surface of each of the structures  33   a  to  33   d  is bonded to the side surface of the base material  44  by the adhesive  30 , and another surface is bonded to the substrate  21  by the adhesive  30 . Also in the embodiment, it is preferable that the adhesive  30  be configured of a material having high thermal conductivity. 
     In the embodiment, the resist layer having high reflectance is provided on the surface of each of the structures  33   a  to  33   d . Thus, the surface of each of the structures  33   a  to  33   d  prevents (suppresses) the light that is reflected from the boundary surface of the sealing member  53  by being emitted from the light emitting layer  43  or prevents a part of the light that is emitted from the phosphor  31  by receiving the light from the light emitting layer  43  from being incident on the base material  44 . Also in the embodiment, two surfaces or more (in the embodiment, four surfaces) of the base material  44  besides a surface on which the light emitting layer  43  is provided are covered by a plurality of structures  33 . Further, an area of half or more of each of side surfaces of the base material  44  is covered by the structures  33 . 
     Further, in the embodiment, the resist layer having high reflectance is provided on the surface of each of the structures  33 . Thus, the light incident on the direction of the base material  44  is reflected from the surface of each of the structures  33   a  to  33   d  and is emitted to the outside of the light emitting module  54 . 
     Further, each of the structures  33   a  to  33   d  covers each of the side surfaces of the base material  44 , and the side surface of the base material  44  and the surface of each of the structures  33   a  to  33   d  are bonded with the adhesive  30  having high thermal conductivity. Thus, the heat that is generated by the light emitting layer  43  and transferred to the base material  44  is efficiently transferred from the side surfaces of the base material  44  to each of the structures  33   a  to  33   d  through the adhesive  30 . Then, each of the structures  33   a  to  33   d  radiates the heat that is transferred from the base material  44  to the second wiring pad  27  and the substrate  21  through the adhesive  30 . Therefore, it is possible to expect that each of the structures  33   a  to  33   d  efficiently radiates the heat that is generated in the LED  45  to the substrate  21 . 
     Moreover, in the light emitting module  54  according to the embodiment, four structures  33  are disposed around the LED  45 , but the example is not limited to the embodiment and one, two or three structures  33  may be disposed around the LED  45 . Further, two, three or four structures  33  may be integrally formed. 
     The third embodiment is described above. 
     As is apparent from the above description, also in the light emitting module  54  of the embodiment, it is possible to expect the improvement in the luminous efficiency of the light emitting module  54 . Further, also in the light emitting module  54  of the embodiment, it is possible to expect that the heat that is generated in the LED  45  is efficiently radiated to the substrate  21 . 
     Fourth Embodiment 
     Next, a fourth embodiment is described with reference to the drawing. In the embodiment, since the configurations of a lighting device  1 , a straight tube type lamp  11  and a light emitting unit  15  are similar to the lighting device  1 , the straight tube type lamp  11  and the light emitting unit  15  of the first embodiment, detailed description thereof is omitted. 
     Configuration of Light Emitting Module  54   
       FIG. 13  is a cross-sectional view of an example of a light emitting module according to the fourth embodiment. Moreover, since configurations to which the same symbols as those in  FIG. 6  are given in  FIG. 13  are the same as the configurations or have similar functions in  FIG. 6 , the description thereof is omitted with exception that is described below. 
     Structures  34  which are formed of a material having high thermal conductivity are provided around the LED  45  so as to surround the LED  45  on the second wiring pad  27 . For example, a cross section of each of the structures  34  is formed in a triangular prism shape that is substantially a right-angled triangle. Thus, one surface of each of the structures  34  is bonded to the side surface of the base material  44  by the adhesive  30  and another surface is bonded to the substrate  21  by the adhesive  30 . Also in the embodiment, it is preferable that the adhesive  30  be configured of a material having high thermal conductivity. 
     In the embodiment, the resist layer having high reflectance is provided on the surface of each of the structures  34 . Thus, the surface of each of the structures  34  prevents (suppresses) the light that is reflected from the boundary surface of the sealing member  53  by being emitted from the light emitting layer  43  or prevents a part of the light that is emitted from the phosphor  31  by receiving the light from the light emitting layer  43  from being incident on the base material  44 . Also in the embodiment, two surfaces or more (in the embodiment, four surfaces) of the base material  44  besides a surface on which the light emitting layer  43  is provided are covered by a plurality of structures  34 . Further, an area of half or more of each of side surfaces of the base material  44  is covered by each of the surfaces of the structures  34 . 
     Further, in the embodiment, the resist layer having high reflectance is provided on the surface of each of the structures  34 . Thus, the light incident on the direction of the base material  44  is reflected from the surface of each of the structures  34  and is emitted to the outside of the light emitting module  54 . 
     Further, each of the structures  34  covers each of the side surfaces of the base material  44 , and the side surface of the base material  44  and the surface of each of the structures  34  are bonded with the adhesive  30  having high thermal conductivity. Thus, the heat that is generated by the light emitting layer  43  and transferred to the base material  44  is efficiently transferred from the side surfaces of the base material  44  to each of the structures  34  through the adhesive  30 . Then, each of the structures  34  radiates the heat that is transferred from the base material  44  to the second wiring pad  27  and the substrate  21  through the adhesive  30 . Therefore, it is possible to expect that each of the structures  34  efficiently radiates the heat that is generated in the LED  45  to the substrate  21 . 
     Moreover, in the light emitting module  54  according to the embodiment, four structures  34  are disposed around the LED  45 , but the example is not limited to the embodiment and one, two or three structures  34  may be disposed around the LED  45 . Further, two, three or four structures  34  may be integrally formed. 
     The fourth embodiment is described above. 
     As is apparent from the above description, also in the light emitting module  54  of the embodiment, it is possible to expect the improvement in the luminous efficiency of the light emitting module  54 . Further, also in the light emitting module  54  of the embodiment, it is possible to expect that the heat that is generated in the LED  45  is efficiently radiated to the substrate  21   
     Fifth Embodiment 
     Next, a fifth embodiment is described with reference to the drawing. In the embodiment, since the configurations of a lighting device  1 , a straight tube type lamp  11  and a light emitting unit  15  are similar to the lighting device  1 , the straight tube type lamp  11  and the light emitting unit  15  of the first embodiment, detailed description thereof is omitted. 
     Configuration of Light Emitting Module  54   
       FIG. 14  is a view of an example of the vicinity of an LED according to the fifth embodiment. Moreover, since configurations to which the same symbols as those in  FIG. 7  are given in  FIG. 14  are the same configurations or have similar functions in  FIG. 7 , the description thereof is omitted with exception that is described below. 
     In the embodiment, the adhesive  30  is formed around the LED  45  so as to be higher than a total height of the LED  45  and to surround the LED  45 . For example, as illustrated in  FIG. 14 , the adhesive  30  is formed so that a length thereof in the thickness direction of the substrate is longer than a length that is obtained by adding a thickness of the base material and a thickness of the light emitting layer. Also in the embodiment, the adhesive  30  is configured of a material having high reflectance. 
     Therefore, a part of the light that is emitted from the light emitting layer  43  is reflected from a surface  35  of the adhesive  30  formed above the upper surface of the light emitting layer  43  and is emitted above the light emitting layer  43 . Therefore, the adhesive  30  suppresses the diffusion of the light that is emitted by the light emitting layer  43  and it is possible to enhance directivity of the light that is emitted from the LED  45 . Further, it is possible to control light distribution of the LED  45  by adjusting an angle of the surface  35  of the adhesive  30  facing the light emitting layer  43 . 
     If the light distribution is controlled as an entirety of the lighting device  1 , an optical member for the control of the light distribution may be provided outside the light emitting module  54 , but there is a problem in that the size or the cost of the device increases. On the other hand, in the light emitting module  54  according to the embodiment, since the control of the light distribution can be performed inside the light emitting module  54 , it is possible to reduce the size, the cost, the weight or the like of the device. 
     The fifth embodiment is described above. 
     Sixth Embodiment 
     Next, a sixth embodiment is described with reference to the drawing. In the embodiment, since the configurations of a lighting device  1 , a straight tube type lamp  11  and a light emitting unit  15  are similar to the lighting device  1 , the straight tube type lamp  11  and the light emitting unit  15  of the first embodiment, detailed description thereof is omitted. 
     Configuration of Light Emitting Module  54   
       FIG. 15  is a view of an example of the vicinity of an LED according to the sixth embodiment. Moreover, since configurations to which the same symbols as those in  FIG. 10  are given in  FIG. 15  are the same as the configurations or have similar functions in  FIG. 10 , the description thereof is omitted with exception that is described below. 
     In the embodiment, the concave section  32  is formed on the substrate  21  so as to be deeper than a total height of the LED  45 . In the embodiment, for example, a surface  36  of the inner wall of the concave section  32  is covered by the resist layer having high reflectance. Therefore, a part of the light that is emitted from the light emitting layer  43  is reflected from the surface  36  of the inner wall of the concave section  32  and is emitted above the light emitting layer  43 . Therefore, the concave section  32  suppresses the diffusion of the light that is emitted by the light emitting layer  43  and it is possible to enhance directivity of the light that is emitted from the LED  45 . Further, it is possible to control the light distribution of the LED  45  by adjusting an angle of the surface  36  of the inner wall of the concave section  32  facing the light emitting layer  43 . 
     The sixth embodiment is described above. 
     Seventh Embodiment 
     Next, a seventh embodiment is described with reference to the drawing. In the embodiment, since the configurations of a lighting device  1 , a straight tube type lamp  11  and a light emitting unit  15  are similar to the lighting device  1 , the straight tube type lamp  11  and the light emitting unit  15  of the first embodiment, detailed description thereof is omitted. 
     Configuration of Light Emitting Module  54   
       FIG. 16  is a view of an example of the vicinity of an LED according to the seventh embodiment. Moreover, since configurations to which the same symbols as those in  FIG. 10  are given in  FIG. 16  are the same as the configurations or have similar functions in  FIG. 10 , the description thereof is omitted with exception that is described below. 
     In the embodiment, the concave section  32  is formed on the substrate  21  so as to be deeper than a total height of the LED  45 . In the embodiment, a surface  37  of the inner wall of the concave section  32  is formed in a bowl shape of which an opening is gradually increased advancing from a position of the upper surface of the light emitting layer  43  to an end of the opening of the concave section  32  in the thickness direction of the substrate  21 , in a state where the LED  45  is fitted into the concave section  32 . For example, the surface  37  of the inner wall of the concave section  32  may be formed in a parabolic shape in which a direction of the bottom of the concave section  32  is convex. 
     In the embodiment, for example, the surface  37  of the bowl shape in the concave section  32  is covered by the resist layer having high reflectance. Therefore, a part of the light that is emitted from the light emitting layer  43  is reflected from the surface  37  of the inner wall of the concave section  32  and is emitted above the light emitting layer  43 . Therefore, the concave section  32  suppresses the diffusion of the light that is emitted by the light emitting layer  43  and it is possible to enhance directivity of the light that is emitted from the LED  45 . Further, it is possible to control the light distribution of the LED  45  by adjusting an angle of the surface  37  of the inner wall of the concave section  32  facing the light emitting layer  43 . 
     The seventh embodiment is described above. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.