Patent Publication Number: US-8540396-B2

Title: Lighting system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of and claims priority to U.S. patent application Ser. No. 13/119,519 filed May 31, 2011 entitled “Lighting Fixture” and also claims priority to PCT Application No. PCT/JP2009/069423 filed on Nov. 16, 2009 which claims priority to Japanese Patent Application No. 2008-305583 filed Nov. 28, 2008, Japanese Patent Application No. 2008-305584 filed Nov. 28, 2008, Japanese Patent Application No. 2008-305585 filed Nov. 28, 2008, Japanese Patent Application No. 2008-333678 filed Dec. 26, 2008 and Japanese Patent Application No. 2008-333680 filed Dec. 26, 2008. The contents of these applications are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     Aspects relate to a lighting fixture using a flat lamp device having a cap portion at its one face side and a light source at the other face side. 
     BACKGROUND 
     Conventionally, a lamp device has been used which uses a GX53-type cap portion standardized by the IEC (International Electrotechnical Commission). The lamp device has a flat lamp device body, the GX53-type cap portion is provided on an upper face side of the lamp device body, a flat light source using a fluorescent lamp, LED or the like is arranged on a lower face side of the lamp device body, and a lighting circuit for lighting the light source is housed inside the lamp device body. On the cap portion, a pair of lamp pins each having a large diameter portion at its top end is projected. The lamp pins of the lamp device are inserted and hooked into a socket device by turning the lamp device, the lamp device is held by the socket device, and power is supplied from the socket device to the lamp pins. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross sectional view of a lighting fixture, in which a lamp device is attached to a socket device, according to a first embodiment of the present invention. 
         FIG. 2  is a cross sectional view of the lighting fixture in which the lamp device is detached from the socket device. 
         FIG. 3  is a perspective view of the socket device and the lamp device which are detached from each other. 
         FIG. 4  is a perspective view of the lamp device. 
         FIG. 5  is a cross sectional view of a lighting fixture according to a second embodiment of the present invention. 
         FIG. 6  is a perspective view of a vertical cross section of a lighting fixture according to a third embodiment of the present invention. 
         FIG. 7  is a perspective view of the partially seen through lighting fixture. 
         FIG. 8  is a perspective view of a lighting fixture, which is partially seen through, according, to a fourth embodiment of the present invention. 
         FIG. 9  is a cross sectional view of a lighting fixture, in which a socket body of a socket device is arranged at a projecting position, according to a fifth embodiment of the present invention. 
         FIG. 10  is a cross sectional view of the lighting fixture in which the socket body of the socket device is arranged at a housing position. 
         FIG. 11  is a perspective view showing a state that a lamp device is attached to/detached from the socket body, which is arranged at the projecting position of the socket device. 
         FIG. 12  is a perspective view showing a state that the lamp device is attached to the socket body, which is arranged at the projecting position of the socket device. 
         FIG. 13  is a perspective view showing a state that the socket body of the socket device is moved to the housing position. 
         FIG. 14  is a cross sectional view of a lighting fixture according to a sixth embodiment of the present invention. 
         FIG. 15  is a cross sectional view of a lighting fixture according to a seventh embodiment of the present invention. 
         FIG. 16  is a side view of a lamp device of a lighting fixture according to an eighth embodiment of the present invention. 
         FIG. 17  is a cross sectional view of the lighting fixture of the eighth embodiment. 
         FIG. 18  is a cross sectional view of a lighting fixture according to a ninth embodiment of the present invention. 
         FIG. 19  is a perspective view of a disassembled lamp device shown in  FIG. 18 . 
         FIG. 20  is a cross sectional view of a lighting fixture according to a tenth embodiment of the present invention. 
         FIG. 21  is a perspective view of a lighting fixture according to an eleventh embodiment of the present invention. 
         FIG. 22  is a perspective view of a lighting fixture according to a twelfth embodiment of the present invention. 
         FIG. 23  is a perspective view of a lamp device and a socket device, which are detached from each other, of a lighting fixture according to a thirteenth embodiment of the present invention. 
         FIG. 24  is a plan view of the lamp device shown in  FIG. 23 . 
         FIGS. 25(   a ) and  25 ( b ) are partial cross sectional views each showing a relationship between a lamp pin of the lamp device and a power supplying portion of the socket device. 
         FIGS. 26(   a ) and  26 ( b ) are partial cross sectional views each showing a relationship between a signal terminal of the lamp device and a signal transmitting portion of the socket device. 
         FIG. 27  is a circuit diagram of the lighting fixture shown in  FIG. 23 . 
         FIG. 28  is a plan view of a lamp device according to a fourteenth embodiment of the present invention. 
         FIG. 29  is a plan view of a lamp device according to a fifteenth embodiment of the present invention. 
         FIG. 30  is a plan view of a lamp device according to a sixteenth embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     When a lamp device is lit, a light source generates heat and heat radiation is necessary. If the heat is also radiated from a cap portion of the lamp device, effective heat radiation performance is obtained. 
     However, in a state that the cap portion of the lamp device is attached to a socket device, the area of the cap portion exposed to the outside becomes small and heat radiation performance is lowered in terms of the attachment structure. Although it is considered that heat is conducted from the cap portion to the socket device side, because a gap is generated between the cap portion and the socket device, and the cap portion and the socket device are not brought into close contact with each other, heat is not efficiently conducted from the cap portion to the socket device side and sufficient heat radiation performance is not obtained. 
     A lighting fixture according to some aspects may include a socket device which holds a cap portion provided at one face side of a flat lamp device and supplies power for lighting a light source arranged at the other face side of the lamp device to the cap portion; a heat radiating body which comes into contact with at least a part of the cap portion of the lamp device held by the socket device; and a pressing body for pressing the cap portion of the lamp device held by the socket device and the heat radiating body in a contact direction. 
     For example, a GX53-type cap structure is used for the cap portion of the lamp device, and a metallic material excellent in thermal conductivity may be used at least at a position where the cap portion comes into contact with the heat radiating body. In addition, a semiconductor light-emitting element such as an LED or an organic EL, a flat discharge lamp, or the like is usable for the light source as long as a flat thin light source is formed. A globe for covering the light source may be attached to the lamp device. 
     For example, a GX53-type cap portion of the lamp device can be attached to the socket device, and the socket device holds the cap portion and can supply power to the cap portion. 
     The heat radiating body is made of, for example, metal excellent in thermal conductivity and heat radiation performance, and may include a heat radiation structure such as fins and may also serve as a metallic reflection body, a fixture body or the like. 
     The pressing body uses, for example, an elastic body such as a spring or rubber, and may press the heat radiating body against the cap portion or press the cap portion against the heat radiating body. 
     The heat radiating body and the pressing body may be separately provided, or a heat radiating body with a pressing function may be singly provided. For example, an integral structure may be employed such as a metallic bellows having a heat radiating function and a pressing function. 
     According to other aspects, a fixture body may be provided on which the socket device is arranged, and the heat radiating body comes into contact with the cap portion of the lamp device and the fixture body. 
     The fixture body and the heat radiating body may be attached in advance so as to come into close contact with each other, or may be pressed against and brought into contact with each other in a contact direction by the pressing body for pressing the cap portion and the heat radiating body in the contact direction. 
     According to yet other aspects, a socket device may include an insertion hole into which a projection portion projected from the center of the cap portion of the lamp device is inserted, and the heat radiating body comes into face-contact with an end face of the projection portion inserted into the socket device. 
     The projection portion of the cap portion may be brought into contact with the heat radiating body by being projected from the socket device, or may be brought into contact with the heat radiating body in a state that the projection portion is not projected from the socket device and the heat radiating body is made to enter the socket device side. 
     Still further, a socket device may include a socket support body and a socket device body to/from which the cap portion of the lamp device can be attached/detached and which is movably supported by the socket support body between a housing position where the socket device body is housed in the socket support body side and a projecting position where the socket device body projects from the socket support body side. 
     The socket support body is, for example, attached to the fixture body or the like of the lighting fixture, and may support the socket device body with any constitution as long as the socket device body is movable between the housing position and the projecting position. A locking structure may also be used which locks the socket device body at the housing position. For the locking structure, a mechanism, for example, a button switch or a knock mechanism of a pen (pencil), can be used which switches a holding position from/to the projecting position to/from the housing position by repeating pressing operations. That is, the socket device body is locked in a manner of being pressed and moved from the projecting position to the housing position by the lamp device, and the lock is cancelled in a manner of slightly pressing the socket device body with the lamp device again so that the socket device body is allowed to move from the housing position to the projecting position. An energizing member such as a spring may be used in a projecting direction of the socket device body. 
     The GX53-type cap portion of the lamp device can be attached to the socket device body, and the socket device body holds the cap portion and can supply power to the cap portion. 
     According to still other aspects, a lamp device may include: a flat lamp device body; a cap portion provided on one face side of the lamp device body; a light source arranged on the other face side of the lamp device body; and a lighting circuit for lighting the light source. 
     The lamp device body and the cap portion may be integrally or separately provided. 
     The lighting circuit may be housed in the lamp device body or arranged together with the light source on the other face side of the lamp device body. 
     Moreover, a globe for covering the light source may be attached to the other face side of the lamp device body. 
     According to some aspects, a lamp device may include: a substrate attachment portion provided on the other face side of the lamp device body; a thermal conduction connection unit for thermally conductively connecting the substrate attachment portion and the cap portion to each other; and a light-emitting module substrate on which semiconductor light-emitting elements as the light source are mounted and which is attached to the substrate attachment portion. 
     The cap portion and substrate attachment portion of the lamp device body may be integrally or separately provided. When the cap portion and the substrate attachment portion are separately provided, these are brought into close contact with each other by the thermal conduction connection unit using a screw-clamping method or screw-engaging method, and the substrate attachment portion side is thermally conductively connected to the cap portion side. When the cap portion and the substrate attachment portion are integrally formed as the thermal conduction connection unit, the substrate attachment portion is thermally conductively connected to the cap portion. 
     In the light-emitting module substrate, for example, a wiring pattern is formed on a metallic substrate via an insulating layer, the semiconductor light-emitting elements are connected onto the wiring pattern. Then, the light-emitting module substrate is closely attached to the substrate attachment portion of the lamp device body with screws, or the like. 
     According to other aspects, a lamp device may include: a substrate attachment portion provided on the other face side of the lamp device body; a projection portion which is formed integrally with the substrate attachment portion and projected from the center of one face side of the substrate attachment portion to the cap portion side; and a light-emitting module substrate on which semiconductor light-emitting elements as the light source are mounted and which is attached to the substrate attachment portion. 
     The inside of the projection portion may be hollow or solid as long as the projection portion is formed integrally with the substrate attachment portion. 
     In the light-emitting module substrate, for example, a wiring pattern is formed on a metallic substrate via an insulating layer, the semiconductor light-emitting elements are mounted onto the wiring pattern. The light-emitting module substrate is closely attached to the substrate attachment portion of the lamp device body with screws, or the like. 
     According to some aspects, a socket device includes: a socket device body for holding the cap portion of the lamp device; a power supplying portion for supplying power to the lamp device held by the socket device body; and a signal transmitting portion for transmitting a signal to the lamp device held by the socket device body, and the lamp device includes: lamp pins which are connectable to the power supplying portion so as to receive power from the power supplying portion of the socket device; signal terminals which are connected to the signal transmitting portion so as to receive a signal transmitted from the signal transmitting portion of the socket device with the lamp pins connected to the power supplying portion; a lighting circuit which receives power from the lamp pins to light the light source; and a control circuit which receives a signal input in the signal terminals to adjust output of the lighting circuit. 
     The socket device body is formed of, for example, insulative synthetic resin, and the power supplying portion and the signal transmitting portion are arranged in the socket device body. 
     The power supplying portion is brought into contact with, and electrically connected to the lamp pins of the lamp device held by the socket device body. 
     The signal transmitting portion is brought into contact with, and electrically connected to the signal terminals of the lamp device held by the socket device body. As long as the signal transmitting portion is brought into contact with, and electrically connectable to the signal terminals in accordance with the shapes of the signal terminals, it may be, for example, arranged inside a hole formed in a surface of the socket device body, provided on the surface of the socket device body or projected from the socket device body. 
     The lamp pin, for example, projects from the cap portion, has a large diameter portion at its top end, is hooked to and held by the socket device by being attached to the socket device, and is electrically connected to the power supplying portion of the socket device so as to receive power. 
     The signal terminal may be, for example, projected from the cap portion, provided on a surface of the cap portion or arranged inside a hole formed in the surface of the cap portion as long as it is brought into contact with and electrically connected to the signal transmitting portion of the socket device with the lamp device held by the socket device. Any signal such as a modulation signal or an RGB signal is adoptable as long as the signal controls output of the light source. 
     Any circuit constitution is applicable to the lighting circuit if it enables output of the lighting circuit to be adjusted. 
     Any constitution is applicable to the control circuit if it enables output of the lighting circuit to be adjusted in accordance with an input signal. 
     According to various aspects, when the cap portion of a lamp device attached to a socket device and the heat radiating body are brought into contact with each other and pressed by a pressing body in a contact direction, a cap portion and a heat radiating body can be reliably brought into close contact with each other, heat can be efficiently conducted from the cap portion to the heat radiating body, and heat of a lamp device can be efficiently radiated from the cap portion. 
     Additionally or alternatively, when the heat radiating body comes into contact with the cap portion of the lamp device and a fixture body, heat can be efficiently conducted from the cap portion to the fixture body and heat of the lamp device can be efficiently radiated from the cap portion. 
     Still further, if an end face of the projection portion, which is inserted into the socket device, of the cap portion and the heat radiating portion comes into face-contact with each other, heat can be efficiently conducted from a projection portion of the cap portion to the heat radiating body. 
     In other examples, if the socket device body is made movable between a housing position where it is housed in a socket support body side and the projecting position where it projects from the socket support side, the lamp device can be easily attached/detached by moving a socket device body to a projecting position even if the socket device is used for a small lighting fixture. In addition, the cap portion of the lamp device and the heat radiating body can be brought into contact with each other by moving the socket device body to the housing position. 
     Moreover, heat of the lamp device can be efficiently radiated from a cap portion by attaching the lamp device to the socket device. 
     According to other aspects, when a light-emitting module substrate is attached to the substrate attachment portion of a lamp device body, and the substrate attachment portion is thermally conductively connected to the cap portion side from the substrate attachment portion side by a thermal conduction connection unit, heat generated by semiconductor light-emitting elements can be efficiently conducted to the cap portion side via a substrate attachment portion and heat radiation performance can be improved. 
     In various examples, if the substrate attachment portion and the projection portion are integrally formed with each other in the lamp device body and a light-emitting module substrate is attached to the other face side of the substrate attachment portion, heat generated by the semiconductor light-emitting elements can be efficiently conducted to a projection portion, which projects from the center of one face side of the substrate attachment portion, via the substrate attachment portion of the lamp device body, heat concentrated at the projection portion can be efficiently radiated from the projection portion, and heat radiation performance can be improved. 
     In still other examples, when power is supplied from a power supplying portion of the socket device to lamp pins of the lamp device and a signal can be transmitted from a signal transmitting portion of the socket device to signal terminals of the lamp device with the power supplying portion and the lamp pins connected to each other, the lamp device, by attaching the lamp device to the socket device, can receive a signal from the socket device and can adjust output of the lighting circuit in accordance with the signal. 
     Hereinafter, embodiments will be described with reference to the drawings. 
       FIGS. 1 to 4  show a first embodiment,  FIG. 1  is a cross sectional view of a lighting fixture in which a lamp device is attached to a socket device,  FIG. 2  is a cross sectional view of the lighting fixture in which the lamp device is detached from the socket device,  FIG. 3  is a perspective view of the socket device and the lamp device which are detached from each other, and  FIG. 4  is a perspective view of the lamp device. 
     A lighting fixture  11  is, for example, a downlight, and includes: a fixture body  12  as a heat radiating body; a socket device  13  attached to the fixture body  12 ; and a flat lamp device  14  attachable to/detachable from the socket device  13 . Moreover, regarding a directional (vertical) relationship of these body and devices, description will be made below by setting a state, where the flat lamp device  14  is horizontally attached, as a reference and defining a cap portion side, which is one face side of the lamp device  14 , as an upper face side and a light source side, which is the other face side of the lamp device  14 , as a lower face side. 
     The fixture body  12  is made of metal, formed so as to serve as a reflection body as well, and has a circular flat plate portion  17  and a reflecting plate portion  18  curvedly bent downward from a circumferential portion of the flat plate portion  17 . An opening portion  19  is formed on a lower face of the reflecting plate portion  18 . 
     The socket device  13  has a cylindrical insulative socket device body  21  made of synthetic resin, and an insertion hole  22  is formed so as to vertically penetrate the center of the socket device body  21 . A pair of projection portions  23  is projected on an inner face of the insertion hole  22  so as to extend to the center of the insertion hole  22 . 
     A pair of socket portions  24  are formed at a lower face of the socket device body  21 . A connection hole  25  is formed in each socket portion  24 , and a bracket (not shown) for supplying power is arranged inside the connection holes  25 . The connection holes  25  are arc-shaped grooves located rotationally symmetric with respect to the center of the socket device body  21 , and an enlarged diameter portion  26  is formed at one end of each arc-shaped groove. 
     A plurality of recess portions  27  are formed on the lower face of the socket device body  21 , a screw shaft  29  of a screw  28  is inserted and arranged in each recess portion  27  from the fixture body  12 , and a nut  31  is screw-engaged with the screw shaft  29  via an elastic body  30  as a pressing body made of, for example, rubber. The socket device  13  is attached to the flat plate portion  17  of the fixture body  12  with these screws  28 , elastic bodies  30  and nuts  31 . 
     The lamp device  14  includes: a flat lamp device body  34 ; a plurality of LEDs  35  which are semiconductor light-emitting elements as a light source arranged on a lower face side of the lamp device body  34 ; a globe  36  for covering the LEDs  35 ; and a lighting circuit  37  for lighting the LEDs  35 , and is thinly formed so that the size of its height direction is smaller than the size of its horizontal direction. 
     The lamp device body  34  is formed of, for example, insulative synthetic resin or metal such as aluminum excellent in heat radiation performance. A GX53-type cap portion  38  is formed on an upper face side which is one face side of the lamp device body  34 , a flat substrate attachment portion  39 , to which the LEDs  35  are attached, is formed on the lower face side which is the other face side thereof, and a housing portion  40  for housing the lighting circuit  37  is formed in the lamp device body  34 . 
     In the cap portion  38 , an annular contact face  41  coming into contact with a lower face of the socket device  13  is formed, and a columnar projection portion  42 , which can be inserted into the insertion hole  22  of the socket device  13 , is projected from the center of the contact face  41 . The projection size of the projection portion  42  is larger than the height of the socket device  13 , that is, the depth of the insertion hole  22 , and an end face  43  of the projection portion  42  penetrates the insertion hole  22  and projects when the lamp device  14  is attached to the socket device  13 . 
     A pair of metallic lamp pins  44  each having conductivity is projected on the contact face  41 . A large diameter portion  45  is formed at a top end of the lamp pin  44 . The large diameter portion  45  of each lamp pin  44  is inserted into the enlarged diameter portion  26  of each connection hole  25  of the socket device  13 , the lamp pin  44  is moved from the enlarged diameter portion  26  to the connection hole  25  by turning the lamp device  14  and electrically connected to a bracket, the large diameter portion  45  is hooked to the bracket or an edge portion of the connection hole  25 , the lamp device  14  is held by the socket device  13 . Moreover, when the lamp device body  34  is made of metal, each lamp pin  44  is attached to the lamp device body  34  via an insulating member. 
     A pair of guide grooves  46 , with which the projection portions  23  of the socket device  13  are engaged, is formed on a peripheral face of the projection portion  42 . The guide groove  46  has an introduction groove portion  47  opened to the end face  43  of the projection portion  42 , an inclined groove portion  48  inclined from the introduction groove portion  47  and a holding groove portion  49  horizontally extending from the inclined groove portion  48 . The introduction groove portions  47  of the guide grooves  46  are aligned with the projection portions  23  of the socket device  13 , the lamp device  14  is raised and turned in an attachment direction, the projection portions  23  and the inclined groove portions  48  are engaged with each other, the lamp device  14  is moved relatively upward, the socket device  13  is moved relatively downward, and engagement positions of the projection portions  23  with the holding groove portions  49  become, as a whole, an attachment position of the lamp device  14  to the socket device  13 . 
     The plurality of LEDs  35  are mounted on a lower face side of a light-emitting module substrate  50 . An upper face of the light-emitting module substrate  50  is brought into close face-contact with and attached to the substrate attachment portion  39  on the lamp device body  34 . The light-emitting module substrate  50  is formed in a manner of, for example, forming a wiring pattern on a metallic substrate via an insulating layer and mounting the LEDs  35  on the wiring pattern, and attached to the substrate attachment portion  39  on the lamp device body  21  so as to come into close contact therewith screws, or the like. A light-emitting module is constituted by the plurality of LEDs  35  and the light-emitting module substrate  50 . 
     The globe  36  is formed of glass or synthetic resin having transparency or light-diffuseness. 
     The lighting circuit  37  includes a lighting circuit substrate (not shown) and lighting circuit components (not shown) mounted on the lighting circuit, each lamp pin  44  is electrically connected to an input portion of the lighting circuit substrate via a lead wire or the like, and the light-emitting module substrate  50  is electrically connected to output portions of the lighting circuit substrate via lead wires or the like. When the lamp device body  34  is made of metal, the lighting circuit substrate and lighting circuit components are housed in the housing portion  40  of the lamp device body  34  via an insulating material. 
     Next, action of the lighting fixture  11  of the first embodiment will be described. 
     As shown in  FIG. 2 , the socket device  13 , to which the lamp device  14  is not yet attached, is pushed upward by pressing of the elastic body  30 , and an upper face of the socket device  13  is brought into contact with the flat plate portion  17  of the fixture body  12 . 
     In order to attach the lamp device  14  to the socket device  13 , the projection portion  42  of the lamp device  14  is inserted into the insertion hole  22  of the socket device  13  from below, the introduction groove portions  47  of the guide grooves  46  provided on the projection portion  42  of the lamp device  14  are aligned with the projection portions  23  of the socket device  13 , the lamp pins  44  of the lamp device  14  are aligned with the enlarged diameter portions  26  of the connection holes  25  of the socket device  13 , and the lamp device  14  is pushed upward and turned in the attachment direction. By pushing upward and turning the lamp device  14  in the attachment direction, the projection portions  23  and the inclined groove portions  48  of the guide grooves  46  are engaged with each other, the lamp device  14  is moved upward, and the end face  43  of the projection portion  23  comes into contact with the flat plate portion  17  of the fixture body  12 . Further, by turning the lamp device  14  in the attachment direction, the socket device  13  moves downward against the pressing of the elastic body  30  in relation to the lamp device  14  which is restricted from moving upward by contact with the flat plate portion  17  of the fixture body  12 . As shown in  FIG. 1 , by engagement of the projection portions  23  and the holding groove portions  49  of the guide grooves  46 , the lamp device  14  is attached to the socket device  13  at the attachment position, and the lamp pins  44  are electrically brought into contact with the brackets of the socket device  13 . 
     Since the socket device  13  is pushed upward by the pressing of the elastic body  30  with the lamp device  14  attached to the socket device  13 , the end face  43  of the projection portion  42  from the upper face of the socket device  13  is pressed against and brought into close face-contact with the flat plate portion  17  of the fixture body  12 . 
     Therefore, when the LEDs  35  of the lamp device  14  are lit, heat generated by the LEDs  35  is conducted from the light-emitting module substrate  50  to the cap portion  38 , efficiently conducted from the end face  43  of the projection portion  42  to the fixture body  12  and efficiently radiated into air or the like. 
     Accordingly, even in the state that the lamp device  14  is attached to the socket device  13  of the fixture body  12 , heat of the lamp device  14  can be sufficiently radiated from the cap portion  38 . Therefore, the lamp device  14  obtains sufficient heat radiation performance, can restrict the temperature of the LED  35  from rising, and can prevent the LED from being thermally deteriorated and having a short life and, in some cases, light-emitting efficiency from being lowered. 
     Moreover, at least either the flat plate portion  17  of the fixture body  12  or the end face  43  of the lamp device  14  may be subjected, for improvement in thermal conductivity from the cap portion  38  to the fixture body  12 , to surface treatment such as polishing for raising smoothness, or a thermally conductive member such as a gel material or heat radiation sheet having flexibility or elasticity and excellent in thermal conductivity may be arranged on at least either the flat plate portion  17  or the end face  43 . 
     In addition, for other embodiments described below, the same symbols are attached to the same structures as those of the first embodiment, and description thereof will be omitted. 
     Next,  FIG. 5  is a cross sectional view of a lighting fixture according to a second embodiment. 
     The fixture body  12  includes: a cylindrical portion  52 ; a top plate portion  53  provided on an upper face of the cylindrical portion  52 ; and a reflecting plate portion  54  projecting obliquely outward from a lower portion of the cylindrical portion  52 . 
     The socket device  13  is fixed to a lower portion side of the cylindrical portion  52  of the fixture body  12 , and a heat radiating plate  55  as a heat radiating body and a spring  56  as a pressing body are arranged in a space between the upper face of the socket device  13  and the top plate portion  53  of the fixture body  12 . 
     The heat radiating plate  55  is made of metal, and includes: a contact portion  57 , which is brought into face-contact with the end face  43  of the projection portion  42  projecting from the cap portion  38  of the lamp device  14  and has an approximately overturned U-shaped cross section, at its center portion; and both ends led outward from the fixture body  12 , and is arranged vertically movably in relation to the fixture body  12 . Fins or the like may be provided at both ends of the heat radiating plate  55  so as to raise the heat radiation effect. 
     The spring  56  is arranged, in a compressed manner, between an upper face of the contact portion  57  of the heat radiating plate  55  and the top plate portion  53  of the fixture body  12 , and presses the heat radiating plate  55  downward. 
     By attaching the lamp device  14  to the socket device  13 , the contact portion  57  of the heat radiating plate  55  is brought into contact with the end face  43  of the projection portion  42  of the cap portion  38  and the contact portion  57  of the heat radiation plate  55  is pressed against and brought into close face-contact with the end face  43  of the projection portion  42  of the cap portion  38  by the spring  56 . 
     Therefore, when the lamp device  14  is lit, heat generated by the LEDs  35  is conducted from the light-emitting module substrate  50  to the cap portion  38 , efficiently conducted from the end face  43  of the projection portion  42  to the heat radiating plate  55  and efficiently radiated into air or the like. 
     Accordingly, even in the state that the lamp device  14  is attached to the socket device  13  of the fixture body  12 , heat of the lamp device  14  can be efficiently radiated from the cap portion  38 . 
     Although the spring  56  is used as the pressing body, the heat radiating plate  55  may be brought into close contact with the end face  43  of the projection portion  42  by elasticity of the heat radiating plate  55  itself. In this case, the spring  56  may be removed and the heat radiating plate  55  can be made to serve as the pressing body. 
     Next,  FIG. 6  is a perspective view of a cross section of a part of a lighting fixture and  FIG. 7  is a perspective view of a partially seen through lighting fixture, according to a third embodiment. 
     A lighting fixture  12  of the third embodiment has the same structure as that of the second embodiment. A heat radiating plate  60  as a heat radiating body and a spring  61  as a pressing body are arranged in the space between the upper face of the socket device  13  and the top plate portion  53  of the fixture body  12 . 
     The heat radiating plate  60  is made of metal, for example, copper, and formed in a ring shape. That is, the heat radiating plate  60  includes: a flat contact portion  62 , which comes into face-contact with the end face  43  of the projection portion  42  of the cap portion  38  of the lamp device  14 , at its lower face; a flat contact portion  63 , which comes into face-contact with the fixture body  12 , at its upper face; and curved side face portions  64  which are formed between both sides of the contact portions  62  and  63  so as to make expansion and contraction of an interval between the contact portions  62  and  63 . 
     The spring  61  is, in a compressed manner, arranged inside the heat radiating plate  60  and between the upper and lower contact portions  62  and  63 . 
     By attaching the lamp device  14  to the socket device  13 , the end face  43  of the projection portion  42  of the cap portion  38  projects from the upper face of the socket device  13  and comes into contact with the contact portion  62  of the lower face of the heat radiating plate  60 . By the spring  61  arranged inside the heat radiating plate  60 , the contact portion  62  of the lower face of the heat radiating plate  60  is pressed against and brought into close face-contact with the end face  43  of the projection portion  42  of the cap portion  38 , and the contact portion  63  of the upper face of the heat radiating plate  60  is pressed against and brought into close face-contact with the fixture body  12 . 
     Therefore, when the lamp device  14  is lit, heat generated by the LEDs  35  is conducted from the light-emitting module substrate  50  to the cap portion  38 , efficiently conducted from the end face  43  of the projection portion  42  to the heat radiating plate  60 , efficiently conducted from the heat radiating plate  60  to the fixture body  12  and efficiently radiated from the fixture body  12  into air or the like. 
     Accordingly, even in the state that the lamp device  14  is attached to the socket device  13  on the fixture body  12 , heat of the lamp device  14  can be efficiently radiated from the cap portion  38 . 
     Moreover, although the spring  61  is used as the pressing body, the heat radiating plate  60  may be brought into close contact with the end face  43  of the projection portion  42  by elasticity of the heat radiating plate  60  itself. In this case, the spring  61  may be removed and the heat radiating plate  60  can be made to serve as the pressing body. 
     Next,  FIG. 8  is a perspective view of a partially seen through lighting fixture, according to a fourth embodiment. 
     A lighting fixture  12  of the fourth embodiment has the same structure as those of the second and third embodiments. A heat radiating member  67  serving as a heat radiating body and a pressing body is arranged in the space between the upper face of the socket device  13  and the top plate portion  53  of the fixture body  12 . The heat radiating member  67  is made of metal, for example, copper, formed in the shape of a cylindrical bellows and arranged between the upper face of the socket device  13  and the top plate portion  53  of the fixture body  12  with the member  67  compressed. 
     By attaching the lamp device  14  to the socket device  13 , the end face  43  of the projection portion  42  of the cap portion  38  projects from the upper face of the socket device  13  and comes into contact with a lower portion of the heat radiating member  67 . By elasticity of the heat radiating member  67 , the lower portion of the heat radiating member  67  is brought into close contact with the end face  43  of the projection portion  42  and an upper portion of the heat radiating member  67  is brought into close contact with the fixture body  12 . 
     Therefore, when the lamp device  14  is lit, heat generated by the LEDs  35  is conducted from the light-emitting module substrate  50  to the cap portion  38 , efficiently conducted from the end face  43  of the projection portion  42  to the heat radiating member  67 , efficiently conducted from the heat radiating member  67  to the fixture body  12  and efficiently radiated from the fixture body  12  into air or the like. 
     Accordingly, even in the state that the lamp device  14  is attached to the socket device  13  of the fixture body  12 , heat of the lamp device  14  can be efficiently radiated from the cap portion  38 . 
     Further, since the one heat radiating member  67  serves as the heat radiating body and the pressing body, the number of components can be reduced. 
     Moreover, it is allowed that the reflecting plate portion  54  is separated from the fixture body  12  and detachably attached to the lamp device  14 . Therefore, heat of the lamp device  14  is conducted to the reflecting plate portion  54 , and heat radiation performance can be improved. Further, the lamp device  14  can be attached to/detached from the socket device  13  by handling the reflecting plate portion  54  and operability can be improved. 
     Next,  FIGS. 9 to 13  show a lighting fixture according to a fifth embodiment.  FIG. 9  is a cross sectional view of the lighting fixture in which a socket body of the socket device is arranged at a projecting position.  FIG. 10  is a cross sectional view of the lighting fixture in which the socket body of the socket device is arranged at a housing position.  FIG. 11  is a perspective view showing a state before the lamp device  11  is attached to the socket body, which is arranged at the projecting position of the socket device.  FIG. 12  is a perspective view showing a state that the lamp device is attached to the socket body, which is arranged at the projecting position of the socket device.  FIG. 13  is a perspective view showing a state that the socket body of the socket device is moved to the housing position. 
     The socket device  13  includes a socket support body  71  attached to the flat plate portion  17  of the fixture body  12  and a socket device body  21  supported vertically movably in relation to the socket support body  71 . 
     The socket support body  71  is made of, for example, metal, and opened downward, and the socket device body  21  is fitted in the socket support body  71  so as to be vertically movable. That is, by the socket support body  71 , the socket device body  21  is movably supported between the housing position where the socket device body  21  is housed in the socket support body  71  and the projecting position where the body  21  projects downward from the socket support body  71 . 
     Springs  72  as an energizing unit for energizing the socket device body  21  to the projecting position are arranged between the socket support body  71  and the socket device body  21 , and a stopper (not shown) for regulating projection of the socket device body  21  at the projecting position is provided on a socket support body  71 . 
     A locking unit (not shown) for locking the socket device body  21  at the housing position is provided between the socket support body  71  and the socket device body  21 . The locking unit functioning like, for example, a push button switch, locks the socket device body  21  to the housing position by pushing upward and moving the socket device body  21  from the projecting position to the housing position with use of the lamp device  14 . In addition, the locking unit unlocks the socket device body  21  by further slightly pushing upward the socket device body  21  with use of the lamp device  14  and allows the socket device body  21  to move down from the housing position to the projecting position. Although action of such a locking unit can be realized by using a spring for energizing the socket device body  21  into the socket support body  71 , and a cam mechanism for regulating a rotation angle or the like, another well-known mechanism may be used as the locking unit. 
     A plurality of columnar ribs  73  each having a vertical axis are projected on an inner circumferential portion of the socket support body  71 , groove portions  74  each of which has a semicircular cross section and engages with each rib  73  are vertically formed at a plurality of locations of an outer circumferential portion of the socket device body  21 , and a locking member  75  is arranged aside of each groove portion  74  so as to be capable of entering/exiting the groove portion  74 . The locking member  75  enters/exits the groove portion  74  in conjunction with turning operation of the lamp device  14  when the lamp device  14  is attached to/detached from the socket device body  21  held at the projecting position, and can be constituted by, for example, the below-described cam mechanism coming into contact with the lamp pin  44 . In a state that the lamp device  14  is not attached to the socket device body  21  located at the projecting position, the locking member  75  enters the groove portion  74  and, when the socket device body  21  starts moving from the projecting position to the housing position, comes into contact with the rib  73  so as to restrict the movement of the socket device body  21 . In a state that the lamp device  14  is connected to the socket device body  21  located at the projecting position, the locking member  75  exits the groove portion  74  and allows the socket device body  21  to move from the projecting position to the housing position. Accordingly, the ribs  73 , the groove portions  74 , the locking members  75  or the like constitute lock units  76  which allow the socket device body  21 , to which the lamp device  14  is attached, to move between the projecting position and the housing position and to restrict the socket device body  21 , to which the lamp device  14  is not attached, from moving from the projecting position to the housing position. 
     In a state that the socket device body  21  moves to the housing position, each rib  73  is positioned in a region, where the locking member  75  enters, in the groove portion  74 , the locking member  75  cannot enter the groove portion  74 , the lamp device  14  interlocking with the locking members  75  cannot be turned in a direction of being detached from the socket device body  21 . Accordingly, the ribs  73 , the groove portions  74 , the locking members  75  or the like constitute a lamp device holding unit  77  for restricting the lamp device  14  from coming off from the socket device body  21  moved to the housing position. 
     A thermally conductive member  78 , to which the lamp device  14  is thermally conductively connected by movement of the socket device body  21 , to which the lamp device  14  is attached, to the housing position, is arranged on the socket support body  71 . 
     As shown in  FIGS. 9 and 11 , the socket device body  21 , to which the lamp device  14  is not attached, of the socket device  13  is projected downward in relation to the socket support body  71  (located at the projecting position), located in the vicinity of the opening portion  19  side of a lower face of the fixture body  12  and held at the projecting position by energization of the springs  72 . 
     The locking member  75  on the socket device body  21  is located below the rib  73  and enters the groove portion  74 , and an upper face of the locking member  75  faces a top end face of the rib  73 . 
     In order to attach the lamp device  14  to the socket device  13 , the lamp device  14  is raised so that each lamp pin  44  of the lamp device  14  is aligned with and inserted into the enlarged diameter portion  26  of each connection hole  25  of the socket device body  21 . Even if each lamp pin  44  of the lamp device  14  is not aligned with the enlarged diameter portion  26  of each connection hole  25  of the socket device body  21  and pushes upward the socket device body  21 , each locking member  75  comes into contact with the top end face of the rib  73 . Accordingly, the socket device body  21  is prevented from moving upward to the housing position, and thus the lamp device  14  can be prevented from being hardly attached to the socket device  13 . 
     After each lamp pin  44  of the lamp device  14  is inserted into the enlarged diameter portion  26  of the connection hole  25  of the socket device body  21 , the lamp device  14  is turned in the attachment direction and attached to the socket device body  21  as shown in  FIG. 12 . 
     When the lamp device  14  is thus attached to the socket device body  21 , the socket device body  21  is located at the projecting position and in the vicinity of the opening portion  19  side of the lower face of the fixture body  12 . Therefore, a space into which fingers are inserted can be formed between a circumferential portion of the lamp device  14  to be attached to the socket device body  21  and the reflecting plate portion  18  of the fixture body  12 , and the lamp device  14  can be, being held by hand, easily attached to the socket device body  21 . 
     By turning the lamp device  14  in the attachment direction, the locking members  75  exit the groove portions  74  in accordance therewith, and the socket device body  21  is allowed to move to the housing position. 
     After the lamp device  14  is attached to the socket device body  21 , the lamp device  14  is pushed upward, and thus the socket device body  21  is pushed upward to the housing position and the lamp device  14  can be held at a predetermined attachment position in the fixture body  12  as shown in  FIGS. 10 and 13 . The socket device body  21  moved to the housing position is locked by the locking unit. 
     The socket device body  21  to which the lamp device  14  is attached is moved to the housing position, and thus the cap portion  38  of the lamp device  14  is brought into close face-contact with the thermally conductive member  78  and the lighting fixture  11  is thereby in a use state. 
     Since the cap portion  38  of the lamp device  14  is brought into close face-contact with the thermally conductive member  78  although heat is generated when the LEDs  35  of the lamp device  14  are lit, the heat generated from the lamp device  14  is efficiently conducted to the fixture body  12  via the thermally conductive member  78  and heat radiation performance of the lamp device  14  can be improved. 
     In the state that the socket device body  21  is located at the housing position, each rib  73  is positioned in the region, where the locking member  75  enters, in the groove portion  74 , the locking member  75  cannot enter the groove portion  74 , and the lamp device  14  interlocking with the locking members  75  cannot be turned in the direction of being detached from the socket device body  21 . 
     On the other hand, in the case of detaching the lamp device  14 , the socket device body  21  located at the housing position is slightly pushed upward via the lamp device  14  so that the lock by the locking unit is canceled, and thus moved downward to the projecting position together with the lamp device  14  by the energization of the spring  72 . 
     When the socket device body  21  is moved downward to the projecting position, the lamp device  14  is turned in the detachment direction and then moved downward, and thus the lamp pins  44  of the lamp device  14  are pulled out from the connection holes  25  of the socket device body  21  and the lamp device  14  can be detached from the socket device body  21 . 
     When the socket device body  21  is moved downward to the projecting position, each locking member  75  on the socket device body  21  moves further downward than the rib  73  and thus enters the groove portion  74  in accordance with turning of the lamp device  14  in the detachment direction, and the socket device body  21  is restricted from moving to the housing position. 
     The socket device body  21  of the socket device  13  can thus be moved between the housing position where it is housed in the socket support body  71  side and the projecting position where it projects from the socket support  71  side. Accordingly, even if the socket device  13  is used for a small lighting fixture, the socket device body  21  is moved to the projecting position in relation to the socket support body  71  attached to the fixture body  12  side, and thus the lamp device  14  can be, with the circumferential portion of the lamp device  14  gripped, easily detached. 
     By the lamp device holding unit  77 , the lamp device  14  is restricted from coming off from the socket device body  21  moved to the housing position and thus the lamp device  14  attached to the socket device  13  can be prevented from coming off from the socket device  13 , and, when the lamp device  14  is detached, the socket device  13  can be reliably held at the projecting position and the lamp device  14  can be easily attached. 
     Next,  FIG. 14  is a cross sectional view of a lighting fixture according to a sixth embodiment. 
     The whole lamp device body  34  of the lamp device  14  is formed of metal such as aluminum excellent in heat radiation performance, made of, for example, an aluminum die casting, and divided into a cap side metallic part  81  constituting the cap portion  38  and a light source side metallic part  82  constituting the substrate attachment portion  39 . The cap side metallic part  81  is formed in the shape of a disk opened downward, and a contact face  84  with which the light source side metallic part  82  comes into contact is formed at an end face of an annular outer circumferential portion  83  of the metallic part  81 . The light source side metallic part  82  is formed in a flat disk shape so as to close an opening of a lower face of the cap side metallic part  81 , and an upper face of a circumferential portion of the metallic part  82  can come into contact with the contact face of the cap side metallic part  81 . The light source side metallic part  82  is fixed to the cap side metallic part  81  with a plurality of screws  85  as a thermal conduction connection unit, and is thermally conductively closely connected to the cap portion side metallic part  81  from the light source side metallic part  82 . 
     An insulating member  86  is interposed between the cap side metallic part  81  of the lamp device body  34  and the lamp pin  44 . 
     The light-emitting module substrate  50  on which the plurality of LEDs  35  are mounted is closely attached to the substrate attachment portion  39  of the lamp device body  34 . 
     The lighting circuit  37  includes a lighting circuit substrate  89  and lighting circuit parts  90  mounted on the lighting circuit substrate  89 , each lamp pin  44  is electrically connected to an input portion of the lighting circuit substrate  89  via a lead wire  91 , and the light-emitting module substrate  50  is electrically connected to output portions of the lighting circuit substrate  89  via lead wires or the like. The lighting circuit substrate  89  is housed in the housing portion  40  of the lamp device body  34  via an insulating material (not shown). 
     In the case where the lamp device  14  is attached to the socket device  13 , the outer circumferential portion  83  of the lamp device body  34  is thermally conductively brought into contact with the reflecting plate portion  18  of the fixture body  12 , and the end face  43  of the projection portion  42  of the lamp device body  34  is thermally conductively brought into contact with the flat plate portion  17  of the fixture body  12 . 
     Therefore, heat generated from the LEDs  35  is efficiently radiated when the LEDs  35  of the lamp device  14  are lit. That is, since the light-emitting module attachment portion  50  is brought into close contact with the substrate attachment portion  39  of the metallic lamp device body  34  and the substrate attachment portion  39  is thermally conductively connected to the cap portion  38  side with the screws  85  as the thermal conduction connection unit, the heat generated from the LEDs  35  can be efficiently conducted to the cap portion  38  side via the substrate attachment portion  39 . The heat conducted to the cap portion  38  is conducted to the fixture body  12  coming into contact with the cap portion  38  and can be efficiently radiated from the fixture body  12 . 
     Moreover, a plurality of slits for dividing the reflecting plate portion  18  in a circumferential direction may be provided in the reflecting plate portion  18 , and the outer circumferential portion  83  of the lamp device body  34  may be brought into close contact with the reflecting plate portion  18  by imparting elasticity to pieces into which the reflecting plate portion  18  is divided. Further, a metallic spring member coming into close contact with the outer circumferential portion  83  of the lamp device body  34  may be separately provided so that heat can be conducted. 
     Next,  FIG. 15  is a cross sectional view of a lighting fixture according to a seventh embodiment. 
     Screw engaging portions  94  are used as a thermal conduction connection unit for thermally conductively connecting the substrate attachment portion  39  side of the lamp device body  34  to the cap portion  38  side of the lamp device body  34 . That is, a screw portion  95  is formed at the outer circumferential portion  83  of the cap side metallic part  81 , and a screw portion  96  for engaging with the screw portion  95  of the cap side metallic part  81  is formed at a circumferential edge portion of the light source side metallic part  82 . 
     Also when a screw-engagement structure is used as a thermal conduction connection unit, heat can be efficiently conducted from the substrate attachment portion  39  side to the cap portion  38  side. 
     Moreover, it is allowed that the lamp device body  34  is vertically divided by a dividing line in a height direction passing the center of the lamp device body  34  and pieces of the divided lamp device bodies are joined to each other by screw-clamping or the like. In this case, the substrate attachment portion  39  side and the cap portion  38  side are integrally constructed as the thermal conduction connection unit, so that heat can be efficiently conducted from the substrate attachment portion  39  side to the cap portion  38  side. 
     Next,  FIG. 16  is a side view of a lamp device and  FIG. 17  is across sectional view of the lighting fixture, according to an eighth embodiment. 
     The flat substrate attachment portion  39 , to which the light-emitting module substrate  50  is thermally conductively attached, is formed on the lower face of the cap portion  38  on the lamp device body  34 , and the housing portion  40  for housing the lighting circuit  37  is formed inside the projection portion  42  of the cap portion  38 . The lamp pins  44  are connected to the lighting circuit  37  in a state that grooves are formed on the substrate attachment portion  39  and lead wires for connecting the lamp pins  44  to the lighting circuit  37  are arranged on the grooves. A part or whole of the projection portion  42  on the lamp device body  34  is divisionally formed so that the lighting circuit  37  can be housed in the housing portion  40 . 
     By attaching the lamp device  14  to the socket device  13 , the contact face  41  of the cap portion  38  of the lamp device  14  is thermally conductively brought into close contact with the fixture body  12 . In this case, opening portions are formed in the fixture body  12  in accordance with positions of the lamp pins  44  of the lamp device  14 , the socket device  13  is arranged so as to face the opening portions, and the lamp pins  44  can be attached to the socket device  13  without coming into contact with the fixture body  12 . 
     Since the substrate attachment portion  39  side and the cap portion  38  side are integrally constituted as the thermal conduction connection unit, heat can be efficiently conducted from the substrate attachment portion  39  side to the cap portion  38  side. 
     Heat conducted to the cap portion  38  is efficiently conducted to the fixture body  12  with which the contact face  41  of the cap portion  38  comes into contact, and can be efficiently radiated. 
     Moreover, the lighting circuit  37  may be arranged on the lower face side of the lamp device body  34  together with the LEDs  35 . In this case, it is unnecessary to provide the housing portion  40  for housing the lighting circuit  37  in the lamp device body  34  and to divisionally form the lamp device body  34 , and the lamp device body  34  can be simplified. 
       FIG. 18  is a cross sectional view of a lighting fixture and  FIG. 19  is a perspective view of the disassembled lamp device, according to a ninth embodiment. 
     The cap portion  38  of the lamp device  14  includes a base  101 , a cover  102  attached to the base  101  and a pair of lamp pins  44  projecting from the cover  102 . 
     The base  101  is made of, for example, metal such as aluminum excellent in thermal conductivity, and constituted by integrally forming the flat disk-shaped (annular) substrate attachment portion  39 , the cylindrical projection portion  42  projecting from the center of an upper face of the substrate attachment portion  39  and an annular wall portion  103  projecting from a circumferential portion of the upper face of the substrate attachment portion  39  with each other. The annular housing portion  40  for housing the lighting circuit  37  is formed between the projection portion  42  and the wall portion  103  on the upper face of the substrate attachment portion  39 . The light-emitting module substrate  50  is screwed to a lower face of the substrate attachment portion  39  of the base  101  so as to come into close face-contact therewith. 
     The cover  102  is made of insulative synthetic resin and formed in a ring shape. The cover  102  is attached so as to close an upper face of the housing portion  40  on the base  101 . 
     The lighting circuit  37  has the annularly formed lighting circuit substrate  89  and is housed and attached into the housing portion  40  on the cap portion  38  via an insulating member (not shown). 
     In the state that the lamp device  14  is attached to the socket device  13 , the projection portion  42  of the lamp device  14  is inserted into the connection hole  22  of the socket device  13 , and the end face  43  of the projection portion  42  is thermally conductively brought into contact with the flat plate portion  17  of the fixture body  12 . Here, it is allowed that a plurality of slits for dividing a part of the flat plate portion  17  of the fixture body  12  are provided in the flat plate portion  17  so as to impart elasticity to small pieces of the divided flat plate portion  17  and the small pieces are thermally conductively brought into contact with the end face  43  of the projection portion  42 . Alternatively, it is allowed that a metallic spring member to be brought into close contact with the end face  43  of the projection portion  42  is separately provided so that the flat plate portion  17  is thermally conductively brought into contact with the end face  43 . 
     When the LEDs  35  of the lamp device  14  are lit, heat generated by the LEDs  35  is efficiently conducted from the light-emitting module substrate  50  to the substrate attachment portion  39  of the base  101  of the cap portion  38  and efficiently conducted to the projection portion  42  formed integrally with the substrate attachment portion  39  of the base  101 . The heat conducted to the projection portion  42  is efficiently conducted from the end face  43  of the projection portion  42  to the fixture body  12  and radiated into air. 
     Therefore, heat generated by the LEDs  35  and conducted to the substrate attachment portion  39  of the base  101  can be efficiently conducted to the projection portion  42  formed integrally with the substrate attachment portion  39 , concentrated to the projection portion  42  and efficiently made to escape the same from the projection portion  42  to the fixture body  12 , and heat radiation performance can be improved. 
     On the other hand, the heat conducted to the substrate attachment portion  39  of the base  101  is also efficiently conducted to the wall portion  103  formed integrally with the substrate attachment portion  39 , and radiated from the wall portion  103  into air. Therefore, radiation performance of heat generated by the LEDs  35  can be improved. 
     Accordingly, the lamp device  14  of the ninth embodiment obtains sufficient heat radiation performance, can restrict the temperature of the LEDs  35  from rising, and can prevent the LED  35  from being thermally deteriorated and having a short life and, in some cases, light-emitting efficiency from being lowered. 
     Next,  FIG. 20  is a cross sectional view of a lighting fixture according to a tenth embodiment. 
     In the lamp device  14 , the projection portion  42  of the base  101  of the cap portion  38  is solidly formed in a columnar shape. In the case where the lamp device  14  is constituted as described above, the contact area between the projection portion  42  and the substrate attachment portion  39  is increased and thermally conductive efficiency is raised, and thus heat generated by the LEDs  35  is easily conducted from the light-emitting module substrate  50  to the end face  43  of the projection portion  42 . Therefore, thermal conductivity from the substrate attachment portion  39  to the projection portion  42  can be improved, and, consequently, radiation performance of heat generated by the LEDs  35  can be further improved. 
     Next,  FIG. 21  is a perspective view of a lighting fixture according to an eleventh embodiment. 
     An exhaust hole  106  is formed in the flat plate portion  17  of the fixture body  12 , and a fan  107  for discharging air in the fixture body  12  from the exhaust hole  106  to the outside is arranged on the flat plate portion  17 . 
     A plurality of vents  108  for making an outer peripheral face of the socket device body  21  communicate with an inner peripheral face of the insertion hole  22  are provided in the socket device  13 . 
     Action of the fan  107  generates an air flow that air under the fixture body  12  is sucked into the fixture body  12  from the opening portion  19  of the lower face of the fixture body  12 , passes through the plurality of vents  108  of the socket device  13 , flows upward through a gap between the inner peripheral face of the insertion hole  22  and the projection portion  42 , which is inserted into the insertion hole  22 , of the lamp device  14 , and is discharged upward from the exhaust hole  106  of the fixture body  12 . 
     The air flow allows heat conducted to the projection portion  42  to be efficiently radiated into air, and, consequently, radiation performance of heat generated by the LEDs  35  to be improved. 
     Next,  FIG. 22  is a perspective view of a lighting fixture according to a twelfth embodiment. 
     Fins  109  are provided on projection portion  42  of the lamp device  14  of the eleventh embodiment shown in  FIG. 21 . The contact area between heat conducted to the projection portion  42  and air flowing by the action of the fan  107  is increased by the fins  109 , and heat radiation performance can be further improved. 
       FIGS. 23 to 27  show a lighting fixture according to a thirteenth embodiment,  FIG. 23  is a perspective view of a disassembled lamp device and socket device, which are detached from each other, of a lighting fixture,  FIG. 24  is a plan view of the lamp device,  FIGS. 25(   a ) and  25 ( b ) are partial cross sectional views each showing a relationship between the lamp pin of the lamp device and a power supplying portion of the socket device.  FIGS. 26(   a ) and  26 ( b ) are partial cross sectional views each showing a relationship between a signal terminal of the lamp device and a signal transmitting portion of the socket device, and  FIG. 27  is a circuit diagram of the lighting fixture. 
     As shown in  FIG. 23 , the lighting fixture  11  is a downlight and includes a fixture body (not shown), the output adjustment type socket device  13  attached to the fixture body, and the lamp device  14  which is attachable to/detachable from the socket device  13  and has an output adjusting function. 
     On the lower face of the socket device body  21  of the socket device  13 , the pair of socket portions  24  are formed symmetrically with respect to the center of the socket device body  21 . As shown in  FIG. 25 , the connection hole  25  for power supply is formed in the socket portion  24 , and a power supplying bracket  111  as a power supplying portion for supplying power to the lamp device  14  is arranged at the inner side of the connection hole  25 . The connection hole  25  is an arc-shaped oblong hole concentric with the socket device body  21 , and the enlarged diameter portion  26  is formed at one end of the connect ion hole  25 . The power supplying bracket  111  is arranged on a side portion of the other end side of the connection hole  25  at a position of being not touched from the outside of the connection hole  25 . 
     As shown in  FIG. 23 , in the lower face of the socket device body  21 , a pair of signal connection holes  112  are formed so as to be orthogonal to the pair of socket portions  24  and symmetric with respect to the center of the socket device body  21 . As shown in  FIG. 26 , a signal bracket  113  as a signal transmitting portion for transmitting a signal to the lamp device  14  is arranged at the inner side of the connection hole  112 . The connection hole  112  is an arc-shaped oblong hole concentric with the socket device body  21 , and a large diameter portion may be provided at one end side of the hole  112 . The signal brackets  113  are arranged so that a part thereof enters the connection hole  112  at the other end side of the connection hole  112 . 
     Power source wires arranged on the fixture body  12  are electrically connected to the power supplying brackets  111 , and signal lines extending from a controller (not shown) or the like are electrically connected to the signal brackets  113 . 
     As shown in  FIGS. 23 and 24 , the pair of conductive metallic lamp pins  44  symmetric with respect to the center of the lamp device  14  is projected on the contact face  41  of the cap portion  38  of the lamp device  14 . In the lamp pins  44 , a shaft portion  44   a  and the large diameter portion  45  located at a top end of the shaft portion  44   a  are formed. When the lamp device  14  is attached to the socket device  13 , the large diameter portion  45  of each lamp pin  44  is inserted into the enlarged diameter portion  26  of each connection hole  25  of the socket device  13  as shown in  FIG. 25(   a ), the shaft portion  44   a  of the lamp pin  44  is moved to the side opposite from the enlarged diameter portion  26  in the connection hole  25  by turning of the lamp device  14  as shown in  FIG. 25(   b ), and thus a peripheral face of the large diameter portion  45  of the lamp pin  44  is brought into contact with and electrically connected to the power supplying bracket  111 , the large diameter portion  45  is hooked to the edge portion of the connection hole  25  and the lamp device  14  is held by the socket device  13 . 
     A pair of conductive metallic signal terminals  115  are projected on the contact face  41  of the cap portion  38  of the lamp device  14 , the terminals  115  being orthogonal to the pair of lamp pins  44  and symmetric with respect to the center of the lamp device  14 . The signal terminal  115  is constituted by a columnar pin. When the lamp device  14  is attached to the socket device  13 , each signal terminal  115  is inserted into one end of each connection hole  112  of the socket device  13  as shown in  FIG. 26(   a ), moved to the other end side of the connection hole  112  by turning of the lamp device  14 , and thus brought into contact with and electrically connected to the signal brackets  113  as shown in  FIG. 26(   b ). 
     The lighting circuit  37  includes the lighting circuit substrate, a power input side of the lighting circuit substrate and the lamp pins  44  are electrically connected to each other via lead wires or the like, and a lighting output side of the lighting circuit substrate and the light-emitting module substrate  50  are electrically connected to each other via lead wires or the like. Further, a control circuit for controlling output of the lighting circuit  37  is mounted on the lighting circuit substrate, and a signal input portion of the control circuit and the signal terminals  115  are electrically connected to each other via lead wires or the like. 
     Next,  FIG. 27  shows a circuit diagram of the lighting fixture  11 . The lighting fixture  11  controls light output of the LEDs  35  of the lamp device  14 , here, subjects the LEDs  35  to light control, by a signal transmitted from the outside. 
     The power supplying brackets  111  of the socket device  13  are connected to a commercial power source e. 
     Input sides of a diode bridge DB 1  which is a full-wave rectifier are connected to the lamp pins  44  of the lamp device  14 . 
     To output sides of the diode bridge DB 1 , there are connected a smoothing capacitor C 1  and a series circuit of a primary winding of a transformer Tr 1  and an NPN-type transistor Q 1  as a switching element for output control. The transistor Q 1  is drive-controlled by a driving circuit, and thus direct current flowing to a secondary side of the transformer Tr 1  is controlled. 
     A rectifying smoothing circuit including a rectifying diode D 1  and a smoothing electrolytic capacitor C 2  are connected to the secondary side of the transformer Tr 1 , and a plurality of series circuits of resistors R 1 , R 2  and R 3 , the LEDs  35 , and  35  and transistors Q 2 , Q 3  and Q 4  are connected in parallel to the rectifying smoothing circuit. 
     A series circuit of a resistor R 4  and an electrolytic capacitor C 3  are connected between the electrolytic capacitor C 2  and the resistors R 1 , R 2  and R 3 , and a control circuit  117  is connected in parallel to the electrolytic capacitor C 3 . PWM signals are supplied from the control circuit  117  to bases of the transistors Q 2 , Q 3  and Q 4  to PWM-control the transistors Q 2 , Q 3  and Q 4 . A light control signal transmitted from the outside is input into the control circuit  117  through the signal brackets  113  of the socket device  13  and the signal terminals  115  of the lamp device  14 . 
     Next, action of the lighting fixture  11  of the thirteenth embodiment will be described. 
     In order to attach the lamp device  14  having a light control function to the light control-type socket device  13 , the large diameter portion  45  of each lamp pin  44  of the lamp device  14  is inserted into the enlarged diameter portion  26  of each connection hole  25  of the socket device  13  as shown in  FIG. 25(   a ), and, simultaneously, each signal terminal  115  is inserted into one end of each connection hole  112  of the socket device  13  as shown in  FIG. 26(   a ). By turning the lamp device  14  in the attachment direction in this state, as shown in  FIG. 25(   b ), the shaft portion  44   a  of each lamp pin  44  is moved to the side opposite from the enlarged diameter portion  26  in the connection hole  25 , the large diameter portion  45  of the lamp pin  44  is brought into contact with and electrically connected to the power supplying bracket  111 , the large diameter portion  45  is hooked to the edge portion of the connection hole  25 , and the lamp device  14  is held by the socket device  13 . At the same time, as shown in  FIG. 26(   b ), each signal terminal  115  is moved to the other end side of the connection hole  112 , and brought into contact with and electrically connected to the signal brackets  113 . 
     Accordingly, by attaching the lamp device  14  to the socket device  13 , the lamp pins  44  of the lamp device  14  are electrically brought into contact with the power supplying brackets  111  of the socket device  13 , and power can be supplied from the socket device  13  to the lamp device  14 . At the same time, the signal terminals  115  of the lamp device  14  are electrically brought into contact with the signal brackets  113  of the socket device  13 , and a signal can be transmitted from the socket device  13  to the lamp device  14 . 
     By turning on the commercial power source e, current from the commercial power source e is rectified by the diode bridge DB 1  and smoothed by the smoothing capacitor C 1 . Current flowing to a primary side of the transformer Tr 1  is controlled by the transistor Q 1 , and direct current flowing to the secondary side of the transformer Tr 1  is controlled so as to have a predetermined value. The direct current flowing through the secondary side of the transformer Tr 1  is supplied to the LEDs  35  and lights the LEDs  35 . 
     Here, the transistors Q 2 , Q 3  and Q 4  are PWM-controlled by the control circuit  117 , and the LEDs  35  are lit while the transistors Q 2 , Q 3  and Q 4  are in an on-period and turned off while the transistors Q 2 , Q 3  and Q 4  are in an off-period. Since the LEDs  35  blink at a high speed although being repeatedly lit and turned off, it appears to a user that the LEDs  35  are continuously lit. 
     The transistors Q 2 , Q 3  and Q 4  are PWM-controlled and the LEDs  35  are subjected to light control based on a light control signal which is input into the control circuit  117  from the outside. 
     Since the lamp pins  44  for receiving power from the socket device  13  and the signal terminals  115  for receiving a signal transmitted from the socket device  13  are provided on the cap portion  38 , output of the lighting circuit  37  is adjusted in accordance with the signal received by the signal terminals  115  and LEDs  35  can be subjected to light control. 
     Specifically, since the signal terminals  115  are connected to the signal brackets  113  in a state that the lamp pins  44  are brought into contact with the power supplying brackets  111 , by attaching the lamp device  14  to the socket device  13 , the LEDs  35  can be subjected to the light control. 
     When a lamp device having no light control function is connected to the socket device  13  for light control, no light control signal is transmitted from the socket device  13  side to the lamp device having no light control function, and the lamp device having no light control function is lit at a predetermined output regardless of a light control signal. 
     Since the signal terminals  115  are projected from the cap portion  38  of the lamp device  14  having the light control function, the lamp device  14  cannot be attached to a non-light control-type socket device. 
     Moreover, as shown in  FIG. 28  showing a fourteenth embodiment, the pair of signal terminals  115  arranged on the cap portion  38  of the lamp device  14  may be arranged together orthogonally to the pair of lamp pins  44 . In this case, an advantage can be obtained that the lamp pins  44  side having high voltage can be separated from the signal terminals  115  side to which a signal is transmitted and which have low voltage. 
     As shown in  FIG. 29  showing a fifteenth embodiment, the pair of signal terminals  115  arranged on the cap portion  38  of the lamp device  14  may be projected from a circumferential portion of the projection portion  42 . In this case, structures corresponding to the connection hole  112  and the signal brackets  113  may be provided at the inside of the insertion hole  22  of the socket device  13 . 
     As shown in  FIG. 30  showing a sixteenth embodiment, the pair of signal terminals  115  arranged on the cap portion  38  of the lamp device  14  may be provided on the end face of the projection portion  42  of the cap portion  38 . In this case, structures corresponding to the signal brackets  113  to be connected to the signal terminals  115  may be arranged at the fixture body  12  side. 
     Moreover, a signal transmitted to the lamp device  14  is not limited to a light control signal for subjecting the LEDs  35  to light control. An RGB signal for adjusting the color of the LED  35  is usable as the signal transmitted as long as the lamp device  14  enables color lighting. 
     Moreover, also in the fifth to sixteenth embodiments, similar to the first to fourth embodiments, the end face  43  of the projection portion  42  of the cap portion  38  and the heat radiating body can be pressed against each other in a contact direction by attaching the lamp device  14  to the socket device  13 . 
     INDUSTRIAL APPLICABILITY 
     The present invention is applied to a downlight, a ceiling built-in type lighting fixture, a ceiling direct attachment-type lighting fixture, a suspending-type lighting fixture, a wall front face fixture and other lighting fixtures. 
     REFERENCE SIGNS LIST 
     
         
         
           
               11  Lighting fixture 
               12  Fixture body as heat radiating body 
               13  Socket device 
               14  Lamp device 
               21  Socket device body 
               22  Insertion hole 
               30  Elastic body as pressing body 
               34  Lamp device body 
               35  LED as light source, semiconductor light-emitting element 
               37  Lighting circuit 
               38  Cap portion 
               39  Substrate attachment portion 
               42  Projection portion 
               44  Lamp pin 
               50  Light-emitting module substrate 
               55  Heat radiating plate as heat radiating body 
               56  Spring as pressing body 
               60  Heat radiating plate as heat radiating body 
               61  Spring as pressing body 
               67  Heat radiating member as heat radiating body and pressing body 
               71  Socket support body 
               85  Screw as thermal conduction connection unit 
               94  Screw engaging portion as thermal conduction connection unit 
               111  Power supplying bracket as power supplying portion 
               113  Signal bracket as signal transmitting portion 
               115  Signal terminal 
               117  Control circuit