Patent Publication Number: US-2013250586-A1

Title: Lighting Device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2012-070022 file on Mar. 26, 2012, the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to a lighting device. 
     BACKGROUND 
     A lighting device including a semiconductor light-emitting element such as an LED (Light Emitting Diode) as a light source has been used. For example, an LED module mounted with the LED is rotated, whereby the lighting device is attached to a socket. In general, a heat conduction sheet or the like is stuck to the LED module. If the lighting device is attached to the socket, the LED module is brought into contact with a thermal radiation member. The lighting device is considered to facilitate replacement of the LED module. However, since the LED module is rotated to be attached and detached, in some cases, the heat conduction sheet is peeled by friction during the rotation, causing deterioration in a thermal radiation effect. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating an example of an external appearance of a lighting device according to a first embodiment; 
         FIG. 2  is a perspective view illustrating an example of the lighting device in a disassembled state; 
         FIG. 3  is a perspective view of an example of the lighting device in a disassembled state; 
         FIG. 4  is a perspective view of an example of the lighting device in a disassembled state; 
         FIG. 5  is a diagram schematically illustrating an enlarged view of a fixing side screwing section according to the first embodiment; 
         FIG. 6  is a perspective view illustrating an example of a light source module in a disassembled state according to the first embodiment; 
         FIG. 7  is a longitudinal sectional view illustrating the lighting device; 
         FIG. 8  is a front view illustrating a thermal radiation module according to the first embodiment; 
         FIG. 9  is an explanatory diagram for explaining an electrode according to a second embodiment; 
         FIG. 10  is an explanatory diagram for explaining the electrode; and 
         FIG. 11  is an explanatory diagram for explaining a ring member according to the second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A lighting device  1  according to an embodiment explained below includes a thermal radiation module  100 ,  500  functioning as a thermal radiation member in which a light source module  300 ,  400  mounted with a light-emitting element is set, the thermal radiation module  100 ,  500  radiating heat generated from the light source module  300 ,  400 ; and a fixing member  200  screwed on a sidewall  103  of the thermal radiation module  100 ,  500  in a state in which the fixing member  200  surrounds the light source module  300 ,  400  and the thermal radiation module  100 ,  500 . 
     In the lighting device  1  according to the embodiment, the fixing member  200  includes a pressing section configured to press the light source module  300 ,  400  in a direction toward the thermal radiation module  100 ,  500  if the fixing member  200  is screwed on the sidewall  103  of the thermal radiation module  100 ,  500 . 
     In the lighting device  1  according to the embodiment, the fixing member  200  includes a bottom wall  210   a  as the pressing section. If the fixing member  200  is screwed on the sidewall  103  of the thermal radiation module  100 ,  500 , the fixing member  200  adjusts, with a cylindrical reflecting section  220  formed from an opening section of the bottom wall  210   a  in a direction away from the light source module  300 ,  400 , a reflecting direction of light emitted by the light-emitting element mounted on the light source module  300 ,  400 . 
     In the lighting device  1  according to the embodiment, the thermal radiation module  100 ,  500  includes, on a setting surface  101 ,  501  on which the light source module  300 ,  400  is set, locking sections  131  and  132  locked to the light source module  300 ,  400 . The light source module  300 ,  400  is set in the thermal radiation module  100 ,  500  in a state in which the light source module  300 ,  400  is locked to the locking sections  131  and  132 . 
     In the lighting device  1  according to the embodiment, the locking sections  131  and  132  of the thermal radiation module  100 ,  500  are formed in a shape projecting from the setting surface  101 ,  501 . In the light source module  300 ,  400 , cutout sections  303  and  304  for locking the locking sections  131  and  132  are formed in positions opposed to the locking sections  131  and  132  in a first surface  301 ,  401  set on the setting surface  101 ,  501  of the thermal radiation module  100 ,  500 . 
     In the lighting device  1  according to the embodiment, in the fixing member  200 , slits  211  and  212  are formed such that fixing side screwing sections  213  and  214  screwed on the sidewall  103  of the thermal radiation module  100 ,  500  are elastically deformable in an outer side direction. Projecting sections  213   a  and  214   a  projecting from the inner surfaces of the fixing side screwing sections  213  and  214  to the inner side are formed. In the thermal radiation module  100 ,  500 , projecting sections  121   a  and  122   a  projecting from heat radiation side screwing sections  121  and  122 , which form the sidewall  103 , screwed with the fixing side screwing sections  213  and  214  to the outer side are formed. 
     In the lighting device  1  according to the embodiment, the thermal radiation side screwing sections  121  and  122  of the thermal radiation module  100 ,  500  are formed in a spiral shape for enabling fixing member  200  to move in a direction toward the thermal radiation module  100 ,  500 . 
     In the lighting device  1  according to the embodiment, the light source module  300 ,  400  includes electrodes  311 ,  312 ,  411 , and  412  for supplying electric power to the light-emitting element. The thermal radiation module  100 ,  500  includes, in positions opposed to the electrodes  311 ,  312 ,  411 , and  412  in the setting surface  101 ,  501  on which the light source module  300 ,  400  is set, electrodes  141 ,  142 ,  511 , and  512  that electrically come into contact with the electrodes  311 ,  312 ,  411 , and  412 . 
     In the lighting device  1  according to the embodiment, the electrodes  411  and  412  are a plurality of semiarcuate electrodes respectively provided on different concentric circles on the surface  401  of the light source module  400  set on the setting surface  501  of the thermal radiation module  500 . The electrodes  511  and  512  are a plurality of circular electrodes provided in positions opposed to the electrodes  411  and  412  in the setting surface  501  of the thermal radiation module  500 . 
     The lighting device  1  according to the embodiment further includes a ring member  380  set on a side surface of the light source module  300 ,  400  and configured to come into contact with the inner wall of the fixing member  200 . 
     First Embodiment 
       FIG. 1  is a perspective view illustrating an example of an external appearance of the lighting device  1  according to a first embodiment. In  FIG. 1 , an example of the lighting device  1  seen from an oblique lower direction is illustrated. The lighting device  1  illustrated in  FIG. 1  is, for example, a lighting device of a downlight type embedded and set in the indoor ceiling. The lighting device  1  illuminates, for example, the inside of a room located in a downward direction illustrated in  FIG. 1  by causing a light-emitting element such as an LED mounted on the inside to emit light. The lighting device  1  includes a thermal radiation module  100  and a fixing member  200 . 
     The thermal radiation module  100  is made of metal having higher heat conductivity and is, for example, a radiation member molded by aluminum die cast. In the thermal radiation module  100 , thermal radiation fins  110  are vertically provided. The thermal radiation fins  110  emit heat generated from the light-emitting element mounted on the inside of the lighting device  1  to the outside. In the figures referred to below, a part of the thermal radiation fins are sometimes denoted by sign  110 . However, members having a plane shape vertically provided in the thermal radiation module  100  correspond to the thermal radiation fins  110 . A part of the thermal radiation module  100  is embedded in the ceiling in the room. For example, in the thermal radiation module  100 , the thermal radiation fins  110  are embedded in the ceiling and a lower end region other than the thermal radiation fins  110  is exposed to the room. 
     The fixing member  200  is made of, for example, synthetic resin having light resistance, heat resistance, and electric insulation. The fixing member  200  includes a fixing section  210  and a reflecting section  220 . The fixing section  210  is screwed on the sidewall of the thermal radiation module  100 . Specifically, a slit  211  is formed in the fixing section  210 . The slit  211  is screwed on the sidewall of the thermal radiation module  100 , whereby the fixing member  200  is attached to the thermal radiation module  100 . 
     The reflecting section  220  is formed in a cylindrical shape opened at both the upper and lower ends. The reflecting section  220  adjusts a luminous intensity distribution direction of light emitted from the light-emitting element mounted on the inside of the lighting device  1 . 
     An example of the lighting device  1  in a disassembled state according to the first embodiment is explained.  FIGS. 2 to 4  are perspective views illustrating examples of the lighting device  1  in a disassembled state according to the first embodiment. In  FIG. 2 , an example in which the lighting device  1  is viewed from an oblique upper direction is illustrated. In  FIG. 3 , an example in which the lighting device  1  is viewed from an oblique lower direction is illustrated. In  FIG. 4 , an enlarged view of the lighting device  1  viewed from the oblique lower direction is illustrated. 
     As illustrated in  FIGS. 2 and 3 , the lighting device  1  includes a light source module  300  besides the thermal radiation module  100  and the fixing member  200  illustrated in  FIG. 1 . As illustrated in  FIG. 3 , the thermal radiation module  100  is formed in a columnar shape and includes a substantially circular setting surface  101  on which the light source module  300  is set. As illustrated in  FIG. 2 , the thermal radiation fins  110  are vertically provided on a substantially circular fin surface  102 , which is the rear surface of the setting surface  101 . 
     In the thermal radiation module  100 , thermal radiation side screwing sections  121  and  122  for screwing with the fixing member  200  are formed on the sidewall  103  between the setting surface  101  and the fin surface  102 . The thermal radiation side screwing sections  121  and  122  are formed in a concave shape formed by shaving the sidewall  103  in a substantially spiral shape. 
     As illustrated in  FIG. 3 , in the thermal radiation module  100 , locking sections  131  and  132  projecting from the setting surface  101  are formed. The locking sections  131  and  132  are formed at the circumferential edge portion of the setting surface  101  and locked to the light source module  300  to play a role of preventing the light source module  300  from rotating. 
     In the thermal radiation module  100 , electrodes  141  and  142  are provided on the setting surface  101 . The electrodes  141  and  142  are electrodes on a receiving side of an attachment plug. Electrodes  311  and  312  of the light source module  300  explained below are inserted into the electrodes  141  and  142 . For example, one electrode  141  of the electrodes  141  and  142  is an anode and the other electrode  142  is a cathode. 
     The light source module  300  is mounted with a light-emitting element such as an LED on the inside. The light source module  300  includes, as illustrated in  FIGS. 2 and 3 , a substantially circular first surface  301  set on the setting surface  101  of the thermal radiation module  100  and a substantially circular second surface  302 , which is the rear surface of the first surface  301 . 
     In the light source module  300 , concave cutout sections  303  and  304  formed by cutting out a part of the circumferential edge portion of the first surface  301  are formed. The cutout section  303  locks the locking section  131  of the thermal radiation module  100 . The cutout section  304  locks the locking section  132  of the thermal radiation module  100 . In this way, the cutout sections  303  and  304  lock the locking sections  131  and  132  to prevent the light source module  300  from rotating. 
     In the light source module  300 , the electrodes  311  and  312  are provided on the first surface  301 . The electrodes  311  and  312  are electrodes on an inserting side of the attachment plug. The electrodes  311  and  312  are arranged in a positional relation same as a positional relation between the electrodes  141  and  142  of the thermal radiation module  100  and inserted into the electrodes  141  and  142 . For example, one electrode  311  of the electrodes  311  and  312  is an anode and the other electrode  312  is a cathode. 
     If the light source module  300  is inserted into the thermal radiation module  100 , the cutout sections  303  and  304  are formed on the first surface  301  of the light source module  300  and the locking sections  131  and  132  are formed on the setting surface  101  of the thermal radiation module  100  such that the cutout sections  303  and  304  are located in positions opposed to the locking sections  131  and  132 . 
     The thermal radiation module  100  is connected to a power supply device to which electric power is supplied from a not-illustrated commercial alternating-current power supply. If the electrode  311  is inserted into the electrode  141  and the electrode  312  is inserted into the electrode  142 , the thermal radiation module  100  supplies the electric power from the commercial alternating-current power supply to the light source module  300 . Consequently, the light source module  300  can cause the light-emitting element mounted on the inside to emit light. 
     The light-emitting element mounted on the light source module  300  is sometimes heated to have high temperature if the light-emitting element emits light. The performance of the light-emitting element is deteriorated if the light-emitting element has high temperature. Therefore, a not-illustrated heat conduction sheet is stuck to the first surface  301  of the light source module  300 . Consequently, the first surface  301  of the light source module  300  and the setting surface  101  of the thermal radiation module  100  come into close surface contact with each other. It is possible to efficiently transmit heat generated from the light source module  300  to the thermal radiation module  100 . As a result, it is possible to efficiently radiate the heat. 
     As illustrated in  FIG. 2 , the fixing member  200  is formed by the fixing section  210  and the reflecting section  220  formed in a cylindrical shape. The fixing section  210  is opened in substantially circular shapes respectively at both the upper and lower ends. The upper end opening section of the fixing section  210  is formed in a shape larger than the outer circle in the sidewall  103  of the thermal radiation module  100  such that the fixing section  210  can be screwed on the sidewall  103  of the thermal radiation module  100 . 
     The slits  211  and  212  are formed in positions opposed to each other on the edge of the upper end opening section of the fixing section  210 . Specifically, as illustrated in  FIG. 4 , the slits  211  and  212  are formed by a notch extending in a lower end direction from the edge of the upper end opening section and a notch extending substantially in parallel to the edge of the upper end opening section. Consequently, in the sidewall of the fixing section  210 , a region surrounded by the slit  211  is formed as the fixing side screwing section  213  and a region surrounded by the slit  212  is formed as the fixing side screwing section  214 . The fixing side screwing sections  213  and  214  are elastic members movable in the outer side direction of the fixing section  210  by the slit  211  and the slit  212 . As illustrated in  FIG. 2 , in the fixing side screwing section  213 , the projecting section  213   a  projecting in the inner side direction (the center direction of the upper end opening section) from the inner wall is formed. In the fixing side screwing section  214 , the projecting section  214   a  is formed. 
     The fixing member  200  is screwed on the sidewall  103  of the thermal radiation module  100  in a state in which the fixing member  200  surrounds the light source module  300  and the thermal radiation module  100 . Consequently, the fixing member  200  fixes the light source module  300  in a state in which the light source module  300  is held between the fixing member  200  and the setting surface  101  of the thermal radiation module  100 . 
     A mechanism in which the light source module  300  and the fixing member  200  are attached to the thermal radiation module  100  is explained with reference to  FIGS. 4 and 5 .  FIG. 5  is a diagram schematically illustrating an enlarged view of the fixing side screwing section  213  according to the first embodiment. In  FIG. 5 , an example in which the setting surface  101  is viewed from the lower direction in  FIG. 4  is illustrated. In  FIG. 5 , the fixing side screwing section  213  of the fixing member  200  is mainly illustrated. 
     As illustrated in  FIG. 4 , the projecting section  121   a  projecting from the sidewall is formed in the thermal radiation side screwing section  121  of the thermal radiation module  100 . Although not illustrated in  FIG. 4 , the projecting section  122   a  is formed in the thermal radiation side screwing section  122  as well (see  FIG. 3 ). In the thermal radiation module  100 , first, the electrodes  311  and  312  of the light source module  300  are inserted into the electrodes  141  and  142  of the thermal radiation module  100 . Consequently, the light source module  300  is supported by the electrodes  141  and  142  to be attached to the thermal radiation module  100 . That is, in the lighting device  1  according to the first embodiment, it is possible to provisionally set the light source module  300  in the thermal radiation module  100  without allowing the light source module  300  to drop. However, since the light source module  300  is supported by the electrodes  141  and  142  and the electrodes  311  and  312 , the first surface  301  of the light source module  300  is not considered to be in close contact with the setting surface  101  of the thermal radiation module  100 . 
     Subsequently, as illustrated in  FIG. 4 , the fixing side screwing section  213  of the fixing member  200  is slid to the thermal radiation side screwing section  121  of the thermal radiation module  100  in the vertical direction with respect to the setting surface  101 . At this point, the fixing side screwing section  214  is also slid to the thermal radiation side screwing section  122 . 
     Thereafter, as illustrated in  FIGS. 4 and 5 , the fixing member  200  is slid in a direction parallel to the setting surface  101 . At this point, the projecting section  213   a  comes into contact with the projecting section  121   a  of the thermal radiation side screwing section  121 . As explained above, since the slit  211  is formed in the fixing side screwing section  213 , the fixing side screwing section  213  has a function of an elastic member movable in the outer side direction. Therefore, the projecting section  213   a  is pushed out in the outer side direction by the projecting section  121   a  and, when passing the projecting section  121   a,  returns to the original state to be locked to the projecting section  121   a.  Similarly, the projecting section  214   a  of the fixing side screwing section  214  is slid in the horizontal direction with respect to the setting surface  101  to be locked to the projecting section  122   a.  Consequently, the fixing member  200  is attached to the thermal radiation module  100  and fixes the light source module  300 . 
     As explained above, in the lighting device  1  according to the first embodiment, the fixing member  200  is screwed on the sidewall  103  of the thermal radiation module  100  to fix the light source module  300  in a state in which the electrodes  311  and  312  of the light source module  300  are inserted into the electrodes  141  and  142  of the thermal radiation module  100 . That is, in the lighting device  1  according to the first embodiment, the light source module  300  is inserted into the electrodes  141  and  142 , which play a role of sockets, without rotating and is fixed by the fixing member  200 . Therefore, the heat conduction sheet stuck to the light source module  300  is not peeled by friction or the like. As a result, in the lighting device  1  according to the first embodiment, it is possible to prevent the thermal radiation effect from being deteriorated. 
     As illustrated in  FIGS. 2 to 4 , the locking sections  131  and  132  of the thermal radiation module  100  are locked to the cutout sections  303  and  304  of the light source module  300 . Therefore, in the lighting device  1  according to the first embodiment, even if the fixing member  200  sliding in the horizontal direction comes into contact with the light source module  300 , the light source module  300  does not rotate. Therefore, in the lighting device  1  according to the first embodiment, it is possible to prevent peeling of the heat conduction sheet. Further, it is possible to prevent stress in the rotating direction of the light source module  300  from being applied to the electrodes  141  and  142  and the electrodes  311  and  312 . That is, in the lighting device  1  according to the first embodiment, it is possible to not only prevent deterioration in the thermal radiation effect but also prevent the electrodes from being damaged. 
     As illustrated in  FIGS. 4 and 5 , the projecting sections  121   a  and  122   a  are formed in the thermal radiation module  100 . The projecting sections  213   a  and  214   a  are formed in the fixing member  200 . Consequently, the lighting device  1  according to the first embodiment can cause an operator, who attaches the fixing member  200  to the thermal radiation module  100 , to feel as if the projecting sections  213   a  and  214   a  pass through the projecting sections  121   a  and  122   a.  Therefore, it is possible to inform the operator that the fixing member  200  is attached to the thermal radiation module  100 . 
     The fixing member  200  attached to the thermal radiation module  100  presses the light source module  300  against the setting surface  101  of the thermal radiation module  100  to bring the first surface  301  of the light source module  300  and the setting surface  101  of the thermal radiation module  100  into close surface contact with each other. Therefore, the thermal radiation effect is improved. The improvement of the thermal radiation effect is explained below. 
     An example of the light source module  300  in a disassembled state according to the first embodiment is explained.  FIG. 6  is a perspective view illustrating the example of the light source module  300  in a disassembled state according to the first embodiment. In  FIG. 6 , an example in which the light source module  300  is viewed from an oblique upper direction is illustrated. 
     As illustrated in  FIG. 6 , the light source module  300  includes electrodes  311  and  312 , an upper housing  320 , a lower housing  330 , a lower surface cover  340 , a frame  350 , a silicon member  360 , and a substrate  370 . 
     The upper housing  320  is fixed to the lower housing  330 . The electrodes  311  and  312 , the frame  350 , the silicon member  360 , and the substrate  370  are held between the upper housing  320  and the lower housing  330 . In the upper housing  320 , through-holes  321  and  322  piercing through the upper and lower surfaces are formed. The distal ends of the electrodes  311  and  312  are inserted through the through-holes  321  and  322 . The upper surface of the upper housing  320  corresponds to the first surface  301  of the light source module  300 . 
     In the lower housing  330 , openings sections opened at both the upper and lower ends are formed. The lower surface cover  340  is a transparent member. The lower surface cover  340  is attached to the lower surface of the lower housing  330  to cover the opening section formed in the lower housing  330 . The frame  350  is mounted on the upper surface of the lower housing  330  to surround the opening section of the lower housing  330 . The silicon member  360  is formed of transparent silicon and placed on the lower housing  330  to be surrounded by the frame  350 . The silicon member  360  covers the opening section of the lower housing  330 . The substrate  370  is mounted with a light-emitting element such as an LED to illuminate the lower direction in  FIG. 6  from the opening section of the lower housing  330 . 
     A cross section of the lighting device  1  according to the first embodiment is explained.  FIG. 7  is a longitudinal sectional view illustrating the lighting device  1  according to the first embodiment. In  FIG. 7 , the thermal radiation fins  110  of the thermal radiation module  100  are not illustrated. In  FIG. 7 , a state in which the fixing member  200  is slid in the vertical direction with respect to the setting surface  101  (a state in which the fixing member  200  moves in the upward direction in  FIG. 4 ) is illustrated. It is assumed that the fixing section  200  is not slid, i.e., rotated in the horizontal direction with respect to the setting surface  101 . 
     As illustrated in  FIG. 7 , the light source module  300  comes into contact with the bottom wall  210   a  of the fixing member  200 . If the fixing member  200  is screwed on the thermal radiation module  100 , the bottom wall  210   a  of the fixing member  200  functions as a pressing section configured to press the light source module  300  in a direction toward the thermal radiation module  100 . The thermal radiation module  100  is explained with reference to  FIG. 8 .  FIG. 8  is a front view illustrating the thermal radiation module  100  according to the first embodiment. 
     As illustrated in  FIG. 8 , the thermal radiation side screwing section  121  of the thermal radiation module  100  is spirally formed to gradually move in the upward direction from the lower end where the fixing member  200  is slid. That is, if the fixing side screwing section  213  of the fixing member  200  slides on the thermal radiation side screwing section  121 , the fixing member  200  moves in the direction toward the thermal radiation module  100 . Therefore, if the fixing side screwing section  213  slides on the thermal radiation side screwing section  121 , the bottom wall  210   a  of the fixing member  200  illustrated in  FIG. 7  moves in the direction toward the setting surface  101  of the thermal radiation module  100  to press the light source module  300  in the direction toward the setting surface  101 . As a result, the first surface  301  of the light source module  300  and the setting surface  101  of the thermal radiation module  100  are brought into close surface contact with each other. Therefore, it is possible to efficiently transmit heat generated from the light source module  300  to the thermal radiation module  100 . As a result, it is possible to efficiently radiate heat. 
     Although not explained above, as illustrated in  FIG. 7 , in the reflecting section  220  of the fixing member  200 , an opening section gradually increasing in size further away from the substrate  370  is formed. A luminous intensity distribution direction of the light from the light-emitting element is determined by the shape of the opening section formed in the reflecting section  220 . 
     As explained above, with the lighting device  1  according to the first embodiment, the light source module  300  is inserted into the electrodes  141  and  142 , which play a role of sockets, without rotating and is fixed by the fixing member  200 . Therefore, with the lighting device  1  according to the first embodiment, the heat conduction sheet stuck to the light source module  300  is not peeled by friction or the like. As a result, it is possible to prevent the thermal radiation effect from being deteriorated. Further, with the lighting device  1  according to the first embodiment, it is possible to detach the fixing member  200  from the thermal radiation module  100  simply by sliding the fixing member  200 . Therefore, it is possible to easily replace the fixing member  200  and the light source module  300 . 
     With the lighting device  1  according to the first embodiment, if the fixing member  200  is screwed on the thermal radiation module  100 , the fixing member  200  presses the light source module  300  in the direction toward the thermal radiation module  100 . Therefore, it is possible to bring the first surface  301  of the light source module  300  and the setting surface  101  of the thermal radiation module  100  into close surface contact with each other and improve the thermal radiation effect. 
     With the lighting device  1  according to the first embodiment, since the thermal radiation module  100  includes the locking sections  131  and  132  locked to the light source module  300 , even if the fixing member  200  is sliding, the light source module  300  does not rotate. Therefore, it is possible to prevent the thermal radiation effect from being deteriorated and prevent the electrodes from being damaged. 
     Second Embodiment 
     The lighting device  1  may be carried out in various different forms other than the first embodiment. In a second embodiment, another form of carrying out the lighting device  1  is explained. 
     In the first embodiment, as in the example illustrated in  FIGS. 2 and 3 , one set of the electrodes  141  and  142  is arranged in the symmetrical positions on the setting surface  101 . Similarly, one set of the electrodes  311  and  312  is arranged in the symmetrical positions on the first surface  301 . However, arrangement positions of the electrodes are not limited to these positions. 
     Electrodes according to the second embodiment are explained with reference to  FIGS. 9 and 10 .  FIGS. 9 and 10  are explanatory diagrams for explaining the electrodes according to the second embodiment. In  FIG. 9 , an example in which a light source module  400  according to the second embodiment is viewed from a first surface  401  (a surface corresponding to the first surface  301  of the light source module  300 ) is illustrated. In  FIG. 10 , an example in which a thermal radiation module  500  according to a second embodiment is viewed from a setting surface  501  (a surface corresponding to the setting surface  101  of the thermal radiation module  100 ) is illustrated. 
     As illustrated in  FIG. 9 , in the light source module  400  according to the second embodiment, semiarcuate electrodes  411  and  412  are respectively provided on different concentric circles. Specifically, on the first surface  401  having a substantially circular shape, the semiarcuate electrode  411  is provided on a concentric circle formed by a predetermined radius and the semiarcuate electrode  412  is provided on a concentric circle formed by a radius larger than the predetermined radius. The electrodes  411  and  412  are electrodes on an inserting side of an attachment plug. Like the electrodes  311  and  312  illustrated in  FIG. 2  and the like, the electrodes  411  and  412  project from the first surface  401 . For example, one electrode  411  of the electrodes  411  and  412  is an anode and the other electrode  412  is a cathode. 
     As illustrated in  FIG. 10 , in the thermal radiation module  500  according to the second embodiment, circular electrodes  511  and  512  are respectively provided on different concentric circles. Specifically, on the setting surface  501  having a substantially circular shape, the circular electrode  511  is provided on a concentric circle formed by a predetermined radius and the circular electrode  512  is provided on a concentric circle formed by a radius larger than the predetermined radius. The electrodes  511  and  512  are electrodes on a receiving side of the attachment plug. Like the electrodes  141  and  142  illustrated in  FIG. 3  and the like, the electrodes  511  and  512  are formed in a concave shape. For example, one electrode  511  of the electrodes  511  and  512  is an anode and the other electrode  512  is a cathode. 
     The electrode  411  of the light source module  400  is inserted into the electrode  511  of the thermal radiation module  500 . The electrode  412  of the light source module  400  is inserted into the electrode  512  of the thermal radiation module  500 . In the case of the examples illustrated in  FIGS. 9  and  10 , the electrode  411  is not inserted into the electrode  512  and the electrode  412  is not inserted into the electrode  511 . That is, in the lighting device  1  according to the second embodiment, it is possible to prevent the electrodes  411  and  412  from being inserted in the wrong electrode  511  or  512  on the receiving side. 
     In the examples illustrated in  FIGS. 9 and 10 , as long as the setting surface  401  and the setting surface  501  are substantially parallel and opposed to each other, irrespective of how the light source module  400  is rotated, the electrodes  411  and  412  are inserted into the electrode  511  or  512 . Therefore, in the lighting device  1  according to the second embodiment, it is possible to easily attach the light source module  400  to the thermal radiation module  500 . 
     In the first embodiment, in the light source module  300 , a ring member  380  set on a side surface of the light source module  300  may be provided. The ring member  380  is explained with reference to  FIG. 11 .  FIG. 11  is an explanatory diagram for explaining the ring member  380  according to the second embodiment. 
     As illustrated in  FIG. 11 , the ring member  380  formed by an elastic member or the like is set on the side surface of the light source module  300 . The ring member  380  is formed such that, when set in the light source module  300 , the ring member  380  has size substantially the same as the opening surface formed by the inner wall of the fixing section  210 . Specifically, if the light source module  300  in which the ring member  380  is set is inserted into the fixing section  210 , the outer circumferential section of the ring member  380  comes into contact with the inner wall of the fixing section  210 . 
     For example, it is assumed that the fixing member  200  is attached to the thermal radiation module  100  in a state in which the light source module  300  in which the ring member  380  is set is inserted into the fixing section  210 . In such a case, since the ring member  380  is in contact with the inner wall of the light source module  300 , the light source module  300  rotates together with the fixing member  200 . Therefore, since the light source module  300  rotates together with the fixing member  200  until the electrodes  311  and  312  of the light source module  300  are inserted into the electrodes  141  and  142  of the thermal radiation module  100 , the operator can easily insert the light source module  300  into the thermal radiation module  100 . After the light source module  300  is inserted into the thermal radiation module  100 , since the locking sections  131  and  132  of the thermal radiation module  100  are locked to the cutout sections  303  and  304  of the light source module  300 , the light source module  300  stops rotating together with the fixing member  200 . Therefore, by rotating the fixing member  200 , the operator can attach the fixing member  200  to the thermal radiation module  100  without rotating the light source module  300 . In this way, since the ring member  380  illustrated in  FIG. 11  is set on the side surface of the light source module  300 , in the lighting device  1  according to the second embodiment, it is possible to easily insert the light source module  300  into the thermal radiation module  100 . 
     In the first embodiment, the fixing member  200  in which the fixing member  210  and the reflecting section  220  are integrally formed, is explained as an example. However, in the fixing member  200 , the fixing section  210  and the reflecting section  220  may be formed detachably attachable. 
     In the embodiments, the downlight is explained as an example. However, the lighting device  1  can be applied to a lighting device fixture for the ceiling and the like other than the ceiling embedded type as well. 
     The shapes, the raw materials, and the materials of the members according to the embodiments are not limited to those explained in the embodiments and illustrated in the figures. For example, the substrate  370  illustrated in  FIG. 6  may be circular rather than rectangular. For example, the electrodes  411  and  412  illustrated in  FIG. 9  may be provided in symmetrical positions on concentric circles on the setting surface  401 . In such a case, the electrode  511  and the electrode  512  illustrated in  FIG. 10  may be formed in positions opposed to the electrodes  411  and  412  and in a semiarcuate shape like the electrodes  411  and  412 . 
     As explained above, according to the embodiments, it is possible to prevent deterioration in the thermal radiation effect. 
     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.