S&F Ref: P046019 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Eye Lighting Systems Corporation, of 1-4-16, of Applicant: Nihonbashi-bakurocho, Chuo-ku, Tokyo, 103-0002, Japan Actual Inventor(s): Masayoshi Miura Keiichirou Kinoshita Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Lighting system The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(6681141_1) - 1 LIGHTING SYSTEM BACKGROUND 1. Field of the Invention 5 The present invention relates to a lighting system (lighting device) suitably used as a high ceiling mount type lighting system. 2. Description of the Related Art An indoor lighting system which is mounted on an indoor ceiling of a factory, a gymnasium, commercial facilities or the like is known as a high ceiling mount type 10 lighting system (see JP-A-2009-301718, for example). In order to implement energy saving and increase the lifetime of high ceiling mount type lighting systems, it has been considered that light emitting elements such as LEDs or the like are used as a light source of a lighting system. However, when the light emitting elements such as LEDs or the like are used as the light source, it is 15 required to efficiently radiate heat generated from the light emitting elements and a mount board on which the light emitting elements are mounted. In order to satisfy this requirement, it is typical to provide a heat radiation structure such as a radiation fin or the like to the lighting system, and as a consequence the weight of the lighting system increases. 20 SUMMARY It is therefore desirable to provide a lighting system that is light in weight and has improved heat radiation performance. Disclosed is a lighting system having a plate-like portion having a plurality of light emitting elements provided on the surface thereof, and a case body in which one of 6651271_1 -2 a power supply circuit for supplying power to the light emitting elements and a power supply wire connected to an external power supply is accommodated, wherein that a through-hole is formed in the plate-like portion so as to penetrate through the plate-like portion, the light emitting elements are arranged around the through-hole, ventilation 5 portion comprising a hollow cylindrical main body having no bottom and plural radiation fins is provided to the back surface of the plate-like portion so as to intercommunicate with the through-hole, the plural radiation fins being provided on at least one of the inner and outer peripheral surfaces of the hollow cylindrical main body so that the radiation fins extend along the ventilation portion and the case body is joined to one end portion of the 10 ventilation portion so that a gap opened to the outside of the ventilation portion is formed in a peripheral direction between the one end portion of the ventilation portion and the case body. In the above lighting system, the plural radiation fins are provided on both the inner and outer peripheral surfaces of the hollow cylindrical main body. 15 Disclosed is another lighting system having a plate-like portion having a plurality of light emitting elements provided on the surface thereof, and a case body in which one of a power supply circuit for supplying power to the light emitting elements and a power supply wire connected to an external power supply is accommodated, characterized in that a through-hole is formed in the plate-like portion so as to penetrate through the 20 plate-like portion, the light emitting elements are arranged around the through-hole, a hollow cylindrical ventilation portion having no bottom is provided to the back surface of the plate-like portion so as to intercommunicate with the through-hole, the case body is joined to one end portion of the ventilation portion so that a gap opened to the outside of the ventilation portion is formed in a peripheral direction between the one end portion of 25 the ventilation portion and the case body, a ventilation hole is formed in the plate-like 8869118 - 2a portion so as to penetrate through the plate-like portion, and a ventilation duct is provided so as to form a ventilation passage between the ventilation duct and the outer peripheral surface of the hollow cylindrical main body of the ventilation portion, wherein the ventilation passage extends from the ventilation hole on the back surface of the plate-like 5 portion to the gap at the one end portion of the ventilation portion so that air flowing through the ventilation passage is discharged to the outside through the gap together with air flowing through the through-hole penetrating through the plate like portion. Any of the above lighting systems further comprise a front cover that covers the front surface of the plate-like portion and has an opening fitted to the through-hole. 10 In any of the above lighting systems, the front cover is provided with ventilation ports. In any of the above lighting systems, the radiation fins comprise long-length radiation fins and short-length radiation fins that are alternately arranged in the outer peripheral direction of the ventilation portion. 15 The above lighting system further comprises a fixing unit that is freely 8869118 -3 detachably secured to a mount place at which the lighting system is mounted, wherein the case body is freely detachably secured to the fixing unit. The above lighting system further comprises a joint portion for joining the case body and the ventilation portion. 5 According to the present disclosure, in the lighting system having the plate-like portion provided with the plural light emitting elements mounted on the surface thereof and the case body in which the power supply circuit for supplying power to the light emitting elements or a power supply wire connected to an external power supply is accommodated, the through-hole is formed so as to penetrate through the plate-like 10 portion, the light emitting elements are arranged around the through-hole, the cylindrical (hollow cylindrical) ventilation portion having no bottom is provided to the back surface of the ventilation portion so as to intercommunicate with the through-hole, the gap is formed at the one end portion of the ventilation portion, and the case body is joined to the end portion of the ventilation portion so that the gap between the case body and the 15 ventilation portion is opened to the outside in the peripheral direction of the ventilation portion. Accordingly, by providing the through-hole, the ventilation portion and the gap, the material forming the lighting body can be reduced, and the weight of the lighting system can be reduced. Furthermore, the ventilation portion intercommunicates with the outside in the peripheral direction through the gap, thereby forming air streams which 20 flow from the lower side of the lighting body through the ventilation portion to the upper side and flows out from the gap between the lighting body and the case body to the outside in the peripheral direction. The heat of the light emitting elements occurring at the front surface side of the plate-like portion can be leaked to the outside by these air streams, and thus the lighting body can be air-cooled by these air streams, Therefore, 6651271_1 -4 the lighting system which is light in weight and excellent in heat radiation can be provided. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a lighting system according to an 5 embodiment of the present invention; Fig. 2 is a plan view showing the lighting system; Fig. 3 is an exploded perspective view showing the lighting system; Fig. 4 is a diagram showing a state of the lighting system in a work of securing a case body to a fixing unit; 10 Fig. 5 is a cross-sectional view of the lighting system; Fig. 6 is a perspective view showing the lighting system from which a front cover is detached; and Figs. 7A to 7C are bottom views showing the lighting system from which the front cover is detached, wherein Fig. 7A shows a state that only a mount board and light 15 emitting elements are mounted, Fig. 7B shows a state that an insulating sheet is provided and Fig. 7C shows a state that a reflection mirror is provided. DETAILED DESCRIPTION OF THE EMBODIMENT At least one embodiment according to the present invention will be described hereunder with reference to the drawings. 20 Fig. 1 is a diagram showing an embodiment of a lighting system 1 according to an embodiment. The lighting system 1 according to this embodiment may be suitably used as a high ceiling mount type lighting system which is used while hanged from the indoor ceiling of a factory, a gymnasium, commercial facilities or the like. In this embodiment, the upper and lower sides of the lighting system 1 are defined as upper 6651271_1 -5 and lower sides of the lighting system 1 under the state that the lighting system 1 is installed with being hanged from the ceiling. The lighting system 1 has a lighting body 10, a case body 30 and a fixing unit 40. The lighting body 10 is a light source unit which has light emitting elements 11 described 5 later and applies light emitted from the light emitting elements 11 through a front cover (glove) 20. The lighting system 1 may be configured so as to contain a power supply circuit (not shown) in the case body 30 and supply power through the power supply circuit to the lighting body 10. Alternatively, an external power supply circuit may be provided at 10 the outside of the lighting system 1, and the lighting system 1 may be configured so that a power supply line provided in the case body 30 is connected to the external power supply circuit to supply power to the lighting body 10 through the power supply line. The case body 30 is configured to be freely detachably secured to the fixing unit 40 so that the lighting system 1 is mounted on a mount face (mount place), and the lighting 15 system 1 may be configured so that the lighting body 10 and the case body 30 can be integrally secured to the fixing unit 40 so as to be freely detachable from the fixing unit 40 under the state that the fixing unit 40 is fixed to the mount face (place) in advance. The lighting body 10 is designed in a circular truncated cone shape so that the lower bottom at the lighting opening 19 side is larger than the upper bottom, and the case body 30 is 20 configured in a cylindrical shape having such a radial dimension that the case body 30 can be continuously joined to the lighting body 10 with keeping the continuity of the radial dimension thereof with the radial dimension of the upper bottom of the lighting body 10. According to this construction, the lighting body 10 and the case body 30 can be joined to each other without damaging design performance of the lighting system 1. A gap S 6651271_1 -6 which opens to the outside of the lighting system 1 is formed along the outer peripheral direction of the lighting system 1 between the lighting body 10 and the case body 30. The lighting body 10 comprises a plate-like portion (or disc or annular portion) 13 and a hollow cylindrical (barrel-like) ventilation portion. A through-hole 14 is formed 5 substantially at the center of the plate-like portion 13 so as to penetrate through the plate-like portion 13 in the up-and-down direction (thickness direction) thereof. The hollow cylindrical ventilation portion 15 is formed on the back surface 13B of the plate-like portion 13. The hollow cylindrical ventilation portion 15 is configured to have no bottom and intercommunicate with the through-hole 14. The ventilation portion 15 10 intercommunicates with the gap S formed between the lighting body 10 and the case body 30, and also opens through the gap S to the outside of the lighting system 1 along the outer peripheral direction of the lighting system 1. The lighting body 10 has a radiation fin 16 disposed along the ventilation portion 15 on the back surface 13B of the plate-like portion 13B. The radiation fin 16 is radially provided around the ventilation 15 portion 15, and has at least one of an outer peripheral side radiation fin 17 provided on the outer peripheral surface 15A of the ventilation portion 15 and an inner peripheral side radiation fin 18 provided on the inner peripheral surface 15B of the ventilation portion 15. The outer peripheral side radiation fin 17 has plural radiation fins, that is, long-length radiation fins 17A and short-length radiation fins 17B which are arranged in the outer 20 peripheral direction of the ventilation portion 15 so as to extend along the ventilation portion 15 (i.e., in the up-and-down direction). The short-length radiation fins 17B are configured to be shorter than the long-length radiation fins 17A. In this embodiment, the long-length radiation fins 17A and the short-length radiation fins 17B are alternately arranged in the outer peripheral direction of the ventilation portion 15. The inner 6651271_1 -7 peripheral side radiation fin 18 has plural radiation fins. Air streams which pass from the lower side of the lighting body 10 through the ventilation portion 15 and flow from the gap S in the outer peripheral direction are formed around the lighting system 1. The inner peripheral side radiation fin 18 is cooled by the 5 air streams flowing through the ventilation portion 15, so that the heat of the inside of the lighting body 10 can be efficiently radiated from the inner peripheral side radiation fin 18. In order to reduce the weight of the lighting system 1, the radiation fin 16 is formed by die casting using metal which is light in weight and has excellent radiation performance such as aluminum, magnesium or the like. The radiation fin 16 is formed 10 vertically to the back surface 13B of the plate-like portion 13 so that pull-out tapering is applied to the long-length fins 17A, the short-length fins 17B and the inner peripheral side radiation fin 18 in the molding direction so as to make the lower portions thereof thicker than the upper portions thereof. According to this construction, the radiation fin 16 comprising the long-length fins 17A, the short-length fins 17B and the inner peripheral 15 side radiation fin 18 can be easily pulled out from the mold in the molding process. Furthermore, each of the long-length fins 17A and the short-length fins 17B is formed substantially in a rectangular triangular shape along the outer peripheral surface 15A. As shown in Figs. 1 and 2, the outer peripheral side radiation fin 17 has joint portions 17C through which the short-length fins 17B and the long-length fins 17A are 20 connected to one another. The dimensions H1 and Li in the height direction and length direction of the short-length fins 17B are set to be shorter than the dimensions H2 and L2 in the height direction and length direction of the long-length fins 17A, respectively. Each joint portion 17C extends from the inner peripheral side end portion 17D of each short-length fin 17B to the adjacent long-length fin 17A. According to this construction, 6651271_1 -8 the heat radiation area of the radiation fin 16 can be increased by providing the joint portions 17C to the radiation fin 16. The adjacent long-length fins 17A are spaced from each other at a predetermined interval so as to enable the radiation fin 16 to be molded by die casting. 5 The interval between the adjacent long-length fins 17A increases to the outer peripheral side in the radial direction of the plate-like portion 13. By using this interval, the short-length fins 17B are provided at the outer peripheral side of the long-length fins 17A. According to this construction, the radiation area can be increased and thus the radiation performance can be enhanced without damaging the casting performance of the 10 radiation fin 16. Furthermore, by providing the joint portions 17C for connecting the short-length fins 17B and the long-length fins 17A, the fluidity of the metal material under casting can be enhanced, and the flow of the material to small thickness portions of the upper end portions of the long-length fins 17A can be enhanced, so that failure of molding of the 15 long-length fins 17C can be prevented. As shown in Fig. 1, the lighting body 10 has a front cover 20 for covering the surface 13A of the plate-like portion 13 at the lighting opening 19. An opening 20A is formed in the front cover 20 so as to fit to the through-hole 14, and the opening 20A intercommunicates with the through-hole 14 and the ventilation portion 15. Plural 20 ventilation ports 21 are formed in the front cover 20 so as to penetrate through the front cover 20 and be arranged in the peripheral direction along the outer periphery of the front cover 20 and the opening portion 20A. Air flows from the ventilation ports 21 to the inside of the front cover 20 along the flow of the air passing through the ventilation portion 15. 6651271_1 As shown in Fig. 3, the case body 30 has a cylindrical (barrel-like) case portion 31 having a bottom, and a joint portion 33 extending downwardly from the lower end portion 32 of the case portion 31. The case portion 31 is provided with plural radiation fins 39 on the outer peripheral surface thereof so that the radiation fins 39 extend in the 5 up-and-down direction along the outer peripheral surface and are arranged radially. When the power supply circuit is accommodated in the case body 30, heat generated from the power supply circuit can be efficiently radiated to the outside by the radiation fins 39. The joint portion 33 has arms 33A and 33B (four arms in this embodiment) 10 arranged at an equal angular interval in the peripheral direction on the outer peripheral surface of the case portion 31. The arms 33A are fixing arms 33A, and fixing portions 35 for fixing the case body 30 to the lighting body 10 through screws 34 are formed in the pair of confronting fixing arms 33A. Furthermore, the arms 33B are ventilation arms 33B which are joined to ventilation ducts 22 of the lighting body 10 described later. The 15 pair of confronting ventilation arms 33B are configured in a hollow bottomless shape so as to have a substantially U-shaped section so that the surface 36 thereof which confronts the gap S between the lighting body 10 and the case body 30 is opened. A connector 37 to which wires extending from the lighting body 10 are connected is provided to the bottom surface 38 of the case body 30. 20 A fixing unit 40 is provided to the upper portion of the case body 30. The fixing unit 40 is fixed to a mount face by screws, a metallic hanger or the like. A hook portion 41 is provided to the upper end portion of the case body 30, and the fixing unit 40 is provided with a holding portion 42 to which the hook portion 41 is hooked to hold the case body 30. 6651271_1 - 10 As shown in Fig. 4, the case body 30 is joined to the lighting body 10 by the joint portions 33, whereby the lighting body 10 and the case body 30 can be integrally secured to the fixing unit 40 so as to be freely detachable from the fixing unit 40. The fixing unit 40 is fixed to the mount face in advance, and the hook portion 41 is hooked to 5 the holding portion 42 of the fixing unit 40 pre-fixed to the mount face, whereby the lighting body 10 and the case body 30 can be easily integrally secured to the mount face so as to be freely detachable from the mount face. With respect to works for the high ceiling mount type lighting systems (for example, an installation work, a maintenance work, etc.), these works must be carried 10 out at a high position. For example, a worker must perform the installation work of fixing the lighting system to the mount face through screws or the like by using one hand while holding the lighting system by the other hand, and this installation work is not easy. However, according to the construction of this embodiment, the fixing unit 40 is fixed to the mount face in advance, and the lighting body 10 and the case body 30 are integrally 1S hooked and secured to the fixing unit 40 so as to be detachable from the fixing unit 40 while the lighting body 10 and the case body 30 are integrally held by both the hands. Therefore, the installation work of the lighting system 1 can be simply and safely performed. That is, the hook portion 41 of the case body 30 is first hooked to the holding portion 42 of the fixing unit 40 pre-fixed to the mount face, and the case body 30 20 is then fixed to the fixing unit 40 by screws 51 while the lighting body 10 and the case body 30 are integrally held by the fixing unit 40. According to this construction, the lighting system 1 can be easily mounted onto the mount face, and further the case body 30 can be prevented from falling off from the fixing unit 40 after the lighting system 1 is fixed to the mount face of the lighting system 1. 6651271_1 - 11 A wiring hole 48 penetrating through the fixing unit 40 is formed in a surface of the fixing unit 40 which faces the mount face, and a power supply wire 49 (see Fig. 5) is connected to the lighting system 1 through the wiring hole 48. As shown in Fig. 5, the lighting body 10 is provided with plural light emitting 5 elements 11 which are arranged on the surface 13A of the plate-like portion 13 along the peripheral direction around the through-hole 14 formed in the plate-like portion 13. Mount boards 12 are thermally connected and provided to the surface 13A of the plate-like portion 13, and the light emitting elements 11 are mounted on the mount boards 12. Reflection mirrors 23 are provided in the space between the plate-like portion 13 and the 10 front cover 20. The radiation direction of light emitted from the light emitting elements 11 may be set to any direction by the reflection mirrors 23. In this embodiment, the reflection mirrors 23 have many reflection bodies 23A which are configured in a truncated quadrangular pyramid shape and arranged around the through-hole 14 as shown in Fig. 6, and the light emitting elements 11 are arranged at the truncated portions 23B of the 15 respective reflection bodies 23A. Furthermore, as shown in Fig. 5, the lighting body has ventilation ducts 22 extending from the back surface 13B of the plate-like portion 13 to the gap S at the end portion 15C of the ventilation portion 15. The ventilation ducts 22 are connected to the ventilation arms 33B and intercommunicate with the gap S through the opened surfaces 20 36 of the ventilation arms 33B. As shown in Fig. 7A, ventilation holes 26 are formed in the plate-like portion 13 so as to penetrate through the plate-like portion 13, and the ventilation ducts 22 are connected to the ventilation holes 26. According to this construction, a ventilation passage is formed between the outer peripheral surface 15A of the ventilation portion 15 and the ventilation ducts 22 in the lighting body 10 so as to 6651271_1 - 12 extend from the ventilation holes 26 through the ventilation ducts 22 to the gap S of the end portion 15C of the ventilation portion 15. As described above, air flows from the ventilation ports 21 provided to the front cover 20 to the inside of the lighting body 20 (the inside of the front cover 20), so that air streams passing through the ventilation holes 26 5 and the ventilation ducts 22 and then flowing to the gap S are formed in the lighting body 10. According to this construction, the heat generated from the light emitting elements 11 and/or the mount boards 12 can be radiated from the ventilation holes 26 through the ventilation ducts 22 and the ventilation arms 33B and further radiated from the gap S of the end portion 15C of the ventilation portion 15 to the outside together with the air 10 streams formed in the lighting body 10. Therefore, the heat from the light emitting elements 11 and/or the mount boards 12 can be discharged to the outside of the lighting system 1 without staying in the lighting system 1, so that the heat radiation performance of the lighting body 10 can be enhanced. Furthermore, by forming the ventilation ducts 22 of the lighting body 10, the weight of the lighting body 10 can be reduced, and both an 15 effect of enhancing the heat radiation performance of the lighting body 10 and an effect of reducing the weight of the lighting system 1 can be obtained at the same time. The ventilation duct 22 can be used as a wire passage through which an electrical wire for supplying power to the light emitting elements 11 is passed. The electrical wire 24 is passed through the inside of the ventilation duct 22, led to the gap S 20 of the end portion 15C of the ventilation portion 15 and connected to a connector 37 provided to the bottom surface 38 of the case body 30. According to this construction, the electrical wire 24 can be wired through the inside of the ventilation duct 22 without passing over the outside of the lighting body 10, and thus the design performance of the lighting system 1 can be enhanced. Furthermore, the ventilation duct 22 can be used 6651271_1 -13 as both a radiation duct and a wiring duct, so that the casting cost of the lighting body 10 can be reduced. As shown in Fig. 6, joint fixing portions 27 which are configured to have the same exterior appearance as the ventilation ducts 22 are provided to the outer peripheral 5 surface 15A of the ventilation portion 15. The joint fixing portions 27 are provided to be located at the positions corresponding to the fixing arms 33A when each ventilation duct 22 and each ventilation arm 33B are fitted to each other, and a screw portion 28 into which a screw 34 is threadably fitted is formed at the upper end portion of each joint fixing portion 27 as shown in Fig. 3. The fixing arm 33A and the joint fixing portion 27 10 are configured so that the fixing portion 35 and the screw portion 28 are engageable with each other, and the fixing portion 35 and the screw portion 28 are fixed to each other by the screw 34, whereby the lighting body 10 and the case body 30 are integrally fixed to each other. Figs. 7A to 7C are diagrams showing the lighting system 1 from which the front 15 cover 20 is detached when the lighting system 1 is viewed from the lighting face side. As shown in Figs. 7A to 7C, the plate-like portion 13 is formed in an annular shape having the through-hole 14 at the substantially center position. As shown in Fig. 7A, the surface 13A of the plate-like portion 13 are sectioned into four substantially equal parts by the ventilation ducts 22 and the joint fixing portions 27 which extend from the 20 back surface 13B of the plate-like portion 13 along the outer peripheral surface 15A of the ventilation portion 15. Each mount board 12 is designed in a substantially rectangular shape and disposed between each ventilation duct 22 and the joint fixing portion 27 on the surface 13A, and the light emitting elements 11 are mounted on the mount boards 12 so as to confront the lighting opening 19. LED, organic LED or the like 6651271_1 - 14 may be suitably used as the light emitting elements 11. As shown in Fig. 7B, ceramic insulating sheets 25 having holes 25A corresponding to light emission faces 11A of the light emitting elements 11 are secured to the surface 13A from the light emission face 11A side of the light emitting elements 11. Furthermore, the reflection mirrors 23 are 5 fixed to the plate-like portion 13 by screws 28 so that the insulating sheets 25 are sandwiched between the plate-like portion 13 and the reflection mirrors 23 as shown in Fig. 7C. The connector 37 is provided to the bottom surface 38 of the case body 30, and a connection port 37A of the connector 37 is opened to the ventilation portion 15. An 10 U-shaped clasp 46 having a substantially U-shaped section is disposed in a cross-shape at the bottom surface 38 to enhance the rigidity of the case body 30, and plural intercommunication holes 47 intercommunicating with the inside of the case body 30 are provided to the U-shaped clasp 46. According to this construction, the heat from the power supply circuit, etc. accommodated in the case body 30 can be radiated through 15 the intercommunication holes 47 to the gap S between the case body 30 and the lighting body 10, thereby preventing the heat from staying in the case body 30. As described above, according to the embodiment to which the present invention is applied, in the lighting system 1 having the plate-like portion 13 provided with the plural light emitting elements 11 mounted on the surface 13A thereof and the case 20 body 30 in which the power supply circuit for supplying power to the light emitting elements 11 or a power supply wire connected to an external power supply is accommodated, the through-hole 14 is formed so as to penetrate through the plate-like portion 13, the light emitting elements 11 are arranged around the through-hole 14, the cylindrical (hollow cylindrical) ventilation portion 15 having no bottom is provided to the 6651271_1 -15 back surface of the ventilation portion 15 so as to intercommunicate with the through-hole 14, the gap S is formed at one end portion 15C of the ventilation portion 15, and the case body 30 is joined to the end portion 15C of the ventilation portion 15 so that the gap S between the case body 30 and the ventilation portion 15 is opened to the 5 outside in the peripheral direction of the ventilation portion 15. Accordingly, by providing the through-hole 14, the ventilation portion 15 and the gap S, the material forming the lighting body 10 can be reduced, and the weight of the lighting system 1 can be reduced. Furthermore, the ventilation portion 15 intercommunicates with the outside in the peripheral direction through the gap S, thereby forming air streams which flow from the 10 lower side of the lighting body 10 through the ventilation portion 15 to the upper side and flows out from the gap S between the lighting body 10 and the case body 3 to the outside in the peripheral direction. The lighting body 10 can be air-cooled by these air streams, whereby the heat generated from the light emitting elements 11 accommodated in the lighting body 10 can be efficiently radiated. Therefore, the lighting system which is light 15 in weight and excellent in heat radiation can be provided. According to the embodiment to which the present invention is applied, the front cover 20 which covers the surface 13A of the plate-like portion 13 and has the opening 20A fitted to the through-hole 14 is provided, and the ventilation holes 26 are formed in the plate-like portion 13 so as to penetrate through the plate-like portion 13, whereby the 20 ventilation passage extending from the ventilation hole 26 of the back surface 13B of the plate-like portion 13 to the gap S of the end portion 15C of the ventilation portion 15 is formed between the outer peripheral surface 15A of the ventilation portion 15 and each ventilation duct 22. Accordingly, air can be made to flow to the ventilation portion 15 through the opening 20A and the through-hole 14 without blocking the through-hole 14 6651271_1 - 16 by the front cover 20, and the lighting body 10 can be efficiently air-cooled by this air flow. Furthermore, the heat of the light emitting elements 11 can be efficiently radiated from the gap S through the ventilation holes 26 and the ventilation ducts 22 without staying between the front cover 20 and the surface 13A of the plate-like portion 13, so that the 5 heat radiation of the lighting body 10 can be enhanced. Still furthermore, the hollow ventilation passage is formed between the ventilation duct 22 and the outer peripheral surface 15A of the ventilation portion 15, so that the weight of the lighting body 10 can be reduced. The ventilation ducts 22 can be used as wiring routes of the electrical wires 24 connected to the light emitting elements 11. Therefore, it is unnecessary to 10 separately provide a wiring duct through which the electrical wire 24 is passed, the casting cost can be reduced, and the electrical wire 24 can be wired (routed) without being viewed from the outside of the lighting system 1, so that the design performance of the lighting system can be enhanced. Furthermore, according to this implementation, the ventilation ports 21 are 15 provided to the front cover 20. Therefore, air is made to flow from the ventilation ports 21 to the inside of the front cover 20, and air streams flowing to the ventilation ducts 22 can be formed in the lighting body 10. Therefore, the heat generated from the light emitting elements 11 can be radiated through the ventilation ducts 22 and further radiated from the gap S to the outside of the lighting system 1 by the air streams without 2 0 staying in the lighting body 10, whereby the heat in the lighting body 10 can be efficiently radiated to the outside. According to this implementation, the plural radiation fins 16 extending along the ventilation portion 15 are provided on the back surface 13B of the plate-like portion 13. Therefore, the radiation area of the ventilation portion 15 can be increased, and the 6651271_1 -17 radiation performance of the lighting system 1 can be enhanced by the radiation fins 16. In this example, the case body 30 is provided with the fixing unit 40 which is freely detachably mounted to the mount face. Accordingly, the fixing unit 40 is fixed to the mount face in advance, and the case body 30 can be simply and freely detachably 5 secured to the fixing 40 while the case body 30 is held by both the hands. Therefore, the lighting system 1 which is installed on a high ceiling or the like can be simply and safely installed, and the workability of the lighting system 1 can be enhanced. The present invention is not limited to the above embodiment, and various modifications may be made without departing from the subject matter of the present 10 invention. In the above embodiment, the inner peripheral side radiation fins 18 are arranged in parallel to the air streams flowing in the ventilation portion 15. However, the present invention is not limited to this style, and the radiation fins 18 may be designed in any shape and disposed in any arrangement insofar as they do not serve as a ventilation resistor to air flowing in the ventilation portion 15, but properly increase the radiation area 15 of the ventilation portion 15 and also they can be molded without damaging the casting performance of the lighting body 10. 6651271_1