AU2012233021B2 - Lamp - Google Patents

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Publication number
AU2012233021B2
AU2012233021B2 AU2012233021A AU2012233021A AU2012233021B2 AU 2012233021 B2 AU2012233021 B2 AU 2012233021B2 AU 2012233021 A AU2012233021 A AU 2012233021A AU 2012233021 A AU2012233021 A AU 2012233021A AU 2012233021 B2 AU2012233021 B2 AU 2012233021B2
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AU
Australia
Prior art keywords
heat radiation
cylindrical portion
radiation fins
lamp according
led lamp
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Active
Application number
AU2012233021A
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AU2012233021A1 (en
Inventor
Hiroyuki Banba
Kenji Kawajiri
Tadashi Oomuro
Takahito Shimizu
Takuya Tauchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Iwasaki Denki KK
Original Assignee
Iwasaki Denki KK
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Priority claimed from JP2011223342A external-priority patent/JP5737120B2/en
Priority claimed from JP2011223345A external-priority patent/JP5772473B2/en
Priority claimed from JP2011223364A external-priority patent/JP5834744B2/en
Priority claimed from JP2011223361A external-priority patent/JP5772474B2/en
Priority claimed from JP2011223360A external-priority patent/JP5790389B2/en
Priority claimed from JP2011223343A external-priority patent/JP5862179B2/en
Priority claimed from JP2011223344A external-priority patent/JP2013084435A/en
Application filed by Iwasaki Denki KK filed Critical Iwasaki Denki KK
Publication of AU2012233021A1 publication Critical patent/AU2012233021A1/en
Application granted granted Critical
Publication of AU2012233021B2 publication Critical patent/AU2012233021B2/en
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Abstract

A lamp (1) including aboard having light emitting elements mounted thereon, a flat plate portion having the board mounted thereon, and a cylindrical portion (2) that extends from the back surface of the flat plate portion, has a base provided to the terminal thereof and contains an electrical circuit board therein, including a plurality of heat radiation fins (25) that are arranged radially around the cylindrical portion (2) on the back surface of the base plate (13) portion and configured to extend along the cylindrical portion (2) so that a gap (S) is formed between the cylindrical portion (2) and each of the heat radiation fins (25), and a joint portion (105) for joining end portions at a cylindrical portion side of at least two paired heatradiationfinstoformanairflowpathbetweenthecylindrical portion and the joint portion. 12 11102 105 12A 2 1 0 3 1 0 6 _1 _ 25- 102 68- 60D -en-232 -- 35 2A -'-- ____----62 10 - 65 --'j

Description

S&F Ref: P046486 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Iwasaki Electric Co., Ltd., of 1-4-16, Nihonbashi of Applicant : bakurocho, Chuo-ku, Tokyo, 103-0002, Japan Actual Inventor(s): Kenji Kawajiri Hiroyuki Banba Takahito Shimizu Takuya Tauchi Tadashi Oomuro Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Lamp The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(6748716_1) LAMP BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base type lamp using light emitting elements such as LEDs(Light Emitting Diodes), organic EL (Electro Luminescence) or the like as a light source. 2. Description of the Related Art A base type LED lamp that is available as an alternative of an electric light bulb has been popular in connection with increase in power and decrease in cost of LED (Light Emitting Diode) as one type of semiconductor light emitting element. This type LED lamp is generally configured so that an LED board having LEDs mounted thereon is mounted on a flat disc (circular plate), a cylindrical (barrel)portion in which an electrical circuit board for a power supply circuit, etc. is accommodated is connected to the back surface of the flat disc, and a base is provided to the terminal (terminating end) of the cylindrical portion (for example, JP-A-2010-010134, JP-A-2009-206104 and JP-A-2011-60754). Furthermore, this type LED lamp has generally adopted a heat radiation structure that the flat disc and the cylindrical portion are formed of thermally conductive material and many heat radiation fins are provided to the cylindrical portion. By providing the heat radiation structure, high-power LED can be mounted.
- 2 However, sufficient heat radiation performance can not be obtained by the conventional heat radiation fins, and particularly the heat generated from the cylindrical portion cannot be efficiently radiated. SUMMARY A need exists to provide a lamp that can obtain high heat radiation performance. According to a first aspect of the present disclosure, a lamp including a board having light emitting elements mounted thereon, a flat plate portion having the board mounted thereon, and a cylindrical portion that extends from the back surface of the flat plate portion, has a base provided to the terminal thereof and contains an electrical circuit board therein, comprises: a plurality of heat radiation fins that are arranged radially around the cylindrical portion on the back surface of the flat plate portion and configured to extend along the cylindrical portion so that agap is formed between the cylindrical portion and each of the heat radiation fins; and a joint portion for joining end portions at a cylindrical portion side of at least two paired heat radiation fins to form an air flow path between the cylindrical portion and the joint portion facing the cylindrical portion, wherein air is introduced from outside through a space between adjacent pairs of heat radiation fins to the air flow path and discharged through a space between other adjacent pairs of heat radiation fins to 9006158_1 - 2a the outside. The lamp may further comprise a distributing fin that is disposed between adjacent pairs of heat radiation fins to distribute an air stream to each of the adjacent pairs of heat radiation fins. 9006158 1 - 3 The lamp may further comprise a short heat radiation fin that is provided between the respective paired heat radiation fins joined through the joint portion and configured to be shorter than the heat radiation fins in the extension length from the back surface of the flat plate portion. The lamp may further comprise a plurality of annular heat radiation fins that are arranged on the back surface of the flat plate portion to surround the cylindrical portion and configured to be shorter than the short heat radiation fins in the extension length from the back surface of the flat plate portion. The lamp may comprise a thermally conductive member that is provided between a heating part of the electrical circuit board and the cylindrical portion to transfer heat of the heating part to the cylindrical portion. In the lamp, each of the heat radiation fins may be molded on the back surface of the flat plate portion integrally with the flat plate portion, and configured to be gradually thinner from the cylindrical portion side to the outer peripheral side. In the lamp, a larger number of light emitting elements may be provided at the outer side of the board that that at the center side of the board. In the lamp, the heat radiation fins may be configured so that the extension length thereof along the cylindrical portion is gradually reduced from the cylindrical portion side to the outer peripheral side.
-4 In the lamp, the thickness of the heat radiation fins may be gradually reduced from the back surface side of the flat plate portion to the base side. The lamp may further comprise a globe covering the board of the flat plate portion, wherein the flat plate portion is configured in a tray-like shape having a side wall at the edge thereof, an edge portion of the globe is fitted to the side wall, the fitting portion between the edge portion of the globe and the side wall is sealed by a seal member, the seal member is provided over the whole periphery of the outer surface of the edge portion of the globe so as to be pressed between the side wall of the flat plate portion and the edge portion of the globe, a projection is provided below the seal member, and a guide and hold groove for introducing the projection of the globe from an upper end side and guiding the projection in a peripheral direction to hold the globe. In the lamp, a fit-in groove may be provided over the whole periphery of the outer surface of the edge portion of the globe, and the seal member may be fitted in the fit-in groove so that the seal member is pressed between the inner surface of the side wall of the flat plate portion and the fit-in groove to seal the fitting portion between the sidewall of the flat plate portion and the edge portion of the globe. The lamp may further comprise a reflection face for reflecting light of the light emitting elements is provided on -5 the inner surface of the edge portion of the globe. In the lamp, the cylindrical portion may be configured to be thinner from the flat plate portion side to the base side, a cylindrical member for linking the cylindrical portion to a socket to which the base is screwed may be mounted on the outer peripheral surface of the cylindrical portion, and a fitting structure portion to be fitted to the cylindrical member when the cylindrical member is mounted may be provided to the outer peripheral surface of the cylindrical portion. In the lamp, the cylindrical member may be a waterproof packing that covers an area extending from the socket having the base mounted thereon to the cylindrical portion to prevent water invasion between the base and the socket. In the lamp, the fitting structure portion may be provided with a convex portion or a concave portion to which an upper edge portion of the waterproof packing is fitted over the whole periphery of the cylindrical portion. In the lamp, a convex portion may be provided over the whole periphery of the inner peripheral surface of the cylindrical member. In the lamp, a connection member may be bridged between at least two heat radiation fins, and an anti-drop support member may be connected to the connection member. In the lamp, the heat radiation fins bridged by the connection member may be provided substantially in parallel to - 6 each other, a hole portion may be formed in each of the substantially parallel heat radiation fins so as to penetrate through the heat radiation fin, the connection member may be configured in a rod-like shape, and the rod-like connection member may be supported through the hole portions of the substantially parallel heat radiation fins. In the lamp, the connection member may be joined to a band wound around the cuter peripheral surface of a lamp holder for supporting the lamp. In the lamp, the lamp may be rotated to be screwed to the lamp holder, and the band may have an adjusting portion for adjusting constriction force of the band and be allowed to be rotatable on the outer peripheral surface of the lamp holder by loosening the constriction force of the band. In the lamp, the connection member may be provided between the flat plate portion and the base so as to be nearer to the base than the center-of-gravity position of the dead weight of the lamp. In the lamp, the connection member may be provided to be nearer to the base than the heat radiation fins of the cylindrical portion. The lamp may further comprise a lead wire unit that is connected through the cylindrical portion to the base to supply power to the plurality of light emitting elements, a bag portion formed at the tip of the cylindrical portion, and an engaging portion that is formed on the outer periphery of the tip so as to be engaged with the base, wherein the bag portion of the tip is projected to the outside of the fitting portion, and the projected bag portion is provided a through-hole unit through which the lead wire unit penetrates. In the lamp, the through-hole unit may have a pair of through-holes, the lead wire unit has a pair of through holes, a pair of introducing portions for guiding the pair of lead wires to the pair of through-holes may be formed on the inner surface of the bag portion, and the introducing portions may be separated fromeach other by a partition wall for bisecting the inner surface. In the lamp, the pair of introducing portions may be configured as conical concaves that are tapered to the through-holes. In the lamp, a groove portion in which one of the lead wires drawn through one of the through-holes to the outside is fittedmaybe formedon the outer peripheral surface of the fitting portion, and the bag portion may configured to project to the outside of the groove portion. According to the lamp of the first aspect, the plural heat radiation fins are provided to the back surface of the flat plate portion on which the board having the light emitting elements mounted thereon is mounted so that the heat radiation fins are arranged radially around the cylindrical portion so as to extend -8 from the back surface of the flat plate portion along the cylindrical portion and form a gap between the cylindrical portion and each heat radiation fin, and the joint portion for joining end portions at the cylindrical portion side of at least two heat radiation fins is provided to form the air flow path between the cylindrical portion and the joint portion. Accordingly, the outer peripheral surface of the cylindrical portion can be air-cooled by air passing through the air flow path, and the electrical circuit board accommodated in the cylindrical portion can be cooled. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing an LED lamp device having an LED lamp according to an embodiment of the present invention; Figs. 2A to 2C are plan view, side view and bottom view which show an exterior appearance construction of the LED lamp; Fig. 3 is an exploded perspective view of the LED lamp when is taken from the upper side; Fig. 4 is a cross-sectional view taken along a line IV-IV of Fig. 2C; Fig. 5 is a bottom view showing the LED lamp from which an annular waterproof packing is detached; Fig. 6 is a cross-sectional view taken along a line IV-IV of Fig. 5; Fig. 7 is a cross-sectional view taken along a line VII-VII of Fig. 5; - 9 Fig. 8 is a partially-enlarged plan view of a fin having a trapezoidal shape having an open lower base (or a V-shape having a flat bottom); Fig. 9 is a plan view of a housing when the housing is viewed from a base plate side; Fig. 10 is a cross-sectional view taken along a line X-X of Fig. 9; Fig. 11 is an enlarged view showing the terminal of an insulating cylinder portion; Fig. 12 is a diagram showing an anti-drop structure of the LED lamp; and Figs. 13A and 13B are diagrams showing a band, wherein Fig. 13A is a plan view and Fig. 13B is a perspective view showing a state that an anti-drop wire is secured; Fig. 14 is a diagram showing the positional relationship between the gravity center position of the deadweight of the LED lamp and a support hole, wherein the upper stage of Fig. 14 shows a setup state and the lower stage of Fig. 14 shows a dropout state; Fig. 15 is a diagram showing the positional relationship between the gravity center position of the deadweight of an LED lamp having a reference construction and a support hole, wherein the upper stage of Fig. 15 shows a setup state and the lower stage of Fig. 15 shows a dropout state; Fig. 16 is a cross-sectional view showing a base plate; - 10 Fig. 17 isanenlargedviewoftheengagementportionbetween a globe and the base plate; Fig. 18 is a diagram showing a reference construction of a structure that the globe is threadably secured to the base plate; and Fig. 19 is an enlarged view of a mount portion of the LED lamp to an exposed socket. DETAILED DESCRIPTION OF THE EMBODIMENT An embodiment according to the present invention will be described with reference to the drawings. In the following embodiment, an LED lamp having LEDs (light emitting diodes) as light sources is representatively described as a lamp having a light emitting element as a light source, but the present invention is not limited to this embodiment. For example, the present invention may be applied to a lamp having another type light emitting element such as an organic EL or the like as a light source. Fig. 1 is a diagram showing an LED lamp device 95 having an LED lamp 1 according to an embodiment of the present invention. The LED lamp device 95 shown in Fig. 1 is an outdoor mount type lighting device used for outdoor billboard lighting, etc. and it has an LED lamp 1, a lamp holder 60 in which the LED lamp 1 is mounted, and an annular waterproof packing 70 secured to the LED lamp 1. The lamp holder 60 is a holder in which an existing light - 11 bulb can be mounted, and the LED lamp 1 is configured to have substantially the same shape and optical characteristic as the existing light bulb, so that the LED lamp 1 can be mounted and used in the lamp holder 60 in place of the existing light bulb. Specifically, the lamp holder 60 has a hollow cylindrical holder housing 62, and an arm fixing unit 64 to which a support arm (not shown) is secured to be freely turnable is provided to the terminal portion 62A of the holder housing 62. The tip 60E of the holder housing 62 is configured to have an opening whose diameter is set so that the tip 60 is fitted to the surface of a glass bulb of an existing light bulb through a waterproof packing with no space therebetween when the existing light bulb is mounted in the holder housing 62. Accordingly, when the light bulb is mounted in the holder housing 62, invasion of water from the edge portion 66 of the opening into the holder housing 62 is prevented. In Fig. 1, a projection 68 provided to the tip 60B of the holder housing 62 is a member for fixing a guard member (not shown) which covers and protects the LED lamp 1 or an existing light bulb. A socket 65 to which the base (metal cap) 3 of the existing light bulb or the LED lamp 1 is screwed is provided in the holder housing62. A powersupplywirewhichisledinfromtheexternal is connected to the socket 65, power is supplied through the socket 65 from the base 3 to the LED lamp 1 or the existing light bulb lamp 1.
- 12 The annular waterproof packing 70 is formed of a rubber molded member, and freely detachably mounted on the cylindrical (barrel) portion 2 (described later) of the LED lamp 1. When the LED lamp 1 is mounted on the lamp holder 60, the annular waterproof packing 70 blocks the opening of the lamp holder 60 and prevents invasion of water from the gap between the lamp holder 60 and the LED lamp 1. It is unnecessary to provide the annular waterproof packing 70 in a case where waterproof is unnecessary, for example, in such a case that the LED lamp 1 is mounted and used in the lamp holder 60 installed indoors or a socket exposed to the outside because the annular waterproof packing 70 is used to prevent invasion of water into the lamp holder 60. However, invasion of dust or the like into the lamp holder 60 can be prevented by mounting the annular waterproof packing 70 when the LED lamp 1 is used indoors. Next, the construction of the LED lamp 1 will be described. Figs. 2A to 2C are diagrams showing the exterior appearance construction of the LED lamp 1, wherein Fig. 2A is a plan view, Fig. 2B is a side view and Fig. 2C is a bottom view. Fig. 3 is an exploded perspective view of the LED lamp 1 which is taken from an upper side, and Fig. 4 is a cross-sectional view taken along a line IV-IV of Fig. 2C. In these figures, a state that the annular waterproof packing 70 is mounted on the LED lamp 1 is shown.
- 13 The LED lamp 1 of this embodiment has a light emitting portion 12, a cylindrical (barrel) portion 2 which extends downwards so as to be vertical to the substantially center of the back surface of the light emitting portion 12 and has a base 3 at the terminal side thereof, and plural heat radiation fins 25 provided to the back surface of the light emitting portion 12, and the annular waterproof packing 70 described above is fitted in the cylindrical portion 2. The light emitting portion 12 emits light upwards from the substantially whole upper surface 12A thereof, and it has plural LEDs (light emitting diodes) 15 as light sources, an LED board 16 which is configured to be substantially circular in plan view and on which the LEDs 15 are mounted, a globe 22 and a base plate 13 as a flat plate portion which is integrally provided to the tip 2C of the cylindrical portion 2. The base plate 13 is a member which is configured to have a disc-like shape in top view and be larger in diameter than the cylindrical portion 2. The cylindrical portion 2 extends downwards substantiallyverticallyfromthesubstantiallycenter portion of the back surface 13A of the base plate 13. As shown in Fig. 3, an insertion opening 14 which intercommunicates with the cylindrical portion 2 is formed in the front surface of the base plate 13, and an electrical circuit board 8 having a power source (power conversion device) for turning on LEDs 15 and a driving circuit mounted thereon is inserted through the insertion - 14 opening and mounted in the cylindrical portion 2. The base plate 13 and the cylindrical portion 2 are integrally molded from the same material, that is, thermally-conductive resin by resin molding using a metal mold. The housing 35 of the LED lamp 1 is constructed by the base plate 13, the cylindrical portion 2 and an insulating cylinder portion 10 described later. Plural LEDs 15 are annularly arranged so as to formacircular ring which is substantially concentric to the cylindrical portion 2, and have outer-peripheral side light emitting portions 15A arranged annularly at the outer peripheral side of the base plate 13 and inner-peripheral side light emitting portions 15B which are arranged annularly at the inner peripheral side to be located on the inner side of the outer-peripheral side light emitting portions 15A. In this case, as an example, with respect to the outer-peripheral side light emitting portions 15A, thirty elements are arranged to be spaced from one another at equal intervals, and with respect to the inner-peripheral side light emittingportions 15B, fifteenelements are arranged tobe spaced from one another at equal intervals. When estimated per unit area, the occupation rate of the LED elements of the outer-peripheral side light emitting portions 15A is larger than that of the inner-peripheral side light emitting portions 15B. That is, a larger number of LEDs 15 are mounted at the outer portion of the LED board 15 (corresponding to the outer peripheral - 15 side light emitting portions 15A) than that at the center portion of the LED board 15 (corresponding to the inner peripheral side light emitting portions 15B), and the amount of heat generation of the outer-peripheral side light emitting portions 15A per unit area is larger than that of the inner-peripheral side light emitting portions 15B. Forexample, LEDs 15are formedbypackagingtheLEDelements. In this embodiment, white-color LED is used as LED 15. It is needless to say that LEDs of other light emission colors than white color may be used as LEDs 15. As shown in Fig. 3, the LED board 16 is configured to have a substantially disc shape so that plural LEDs 15 are mounted on the front surface as the upper surface thereof, and fixed to the upper surface of the base plate 13 by plural screws 18. A lead wire draw-out opening 17 is formed at the substantially center portion of the LED board 16. Apair of lead wires 21A and 21B (Fig. 4) for power supply is drawn out from the electrical circuit board 8 mounted in the cylindrical portion 2 through the lead-wire draw-out opening 17, and electrically connected to a circuit pattern (not shown) formed on the upper surface of the LED board 16, whereby each LED 15 is supplied with power through the circuit pattern and turned on. As shown in Figs. 3 and 4, the base plate 13 is configured in a tray-like shape so as to have a flat disc and a side wall 19 along the peripheral edge of the flat disc, and the globe - 16 22 covering the LED board 16 is fitted to the inner peripheral surface of the side wall 19 and held by the base plate 13. An o ring 26 as a seal member is provided between the globe 22 and the base plate 13, the 0 ring 26 is pressed between the globe 22 and the side wall 19 of the base plate 13 in connection with the fitting between the globe 22 and the side wall 19 of the baseplate 13andsealed, therebywaterproofingthelightemission portion 12. The fixing structure of the globe 22 and the base plate 13 will be described in more detail later. As not shown in the figures, the model number (brand number) of the LED lamp 1 is provided to the inner surface of the globe 22 by printing, stamp or the like. Accordingly, the model number (brand number) is prevented from vanishing even when the LED lamp 1 is exposed to weather, and also prevented from vanishing due to friction. The heat radiation fins 25 are radially provided around the cylindrical portion 2 when viewed from the back surface 13A of the base plate 13. Each heat radiation fin 25 is provided so as to extend from the back surface 13A along the cylindrical portion 2, and radiates heat emitted from the LED board 16 mounted on the base plate 13. Each heat radiation fin 25 is formed integrally with the cylindrical portion 2 inan injection molding process for the housing 35. The terminal 2A of the cylindrical portion 2 is integrally provided with a barrel type insulating cylinder portion 10 formed - 17 of an insulatingmaterial to insulate the base 3 and the cylindrical portion 2 fromeach other, and the base 3 ismountedon the terminal 10A of the insulating cylinder portion 10 like a crown as shown in Fig. 4. The electrical circuit board 8 is mounted from the tip side of the cylindrical portion 2 over the insulating cylinder portion 10, and electrically connected to the base 3 through the leadwires 21Aand 21B at the terminal portion of the insulating cylinder portion 10 side. The base 3 has a threaded cylindrical shell 5 which is screwed into a socket 65 (for example, E39 or E26 (E39 in this embodiment) type socket) ofanexisting (established) lampholder 60, and an eyelet 7 provided to the apex portion of the end portion of the shell 5 through the insulating portion 6, and the shell 5 and the eyelet 7 are configured in such a dimension that they can be mounted in an existing socket. Accordingly, the LED lamp 1 can be mounted in an existing socket on the ceiling or wall surface or in the socket 65 of the lamp holder 60 in which an existing light bulb is mounted and used, whereby the LED lamp 1 can be used as an alternative for an existing light bulb. As described above, the shell 5 and the cylindrical portion 2 are electrically insulated from each other by the insulating cylinder portion 10. Therefore, even when the cylindrical portion 2 is formed of a material having electrical conductivity, the insulation between the shell 5 of the base 3 and the cylindrical portion 2 can be kept excellent.
- 18 When a metal material such as aluminum or the like is used for the cylindrical portion 2, it has high heat radiation performance. However, the housing 35 containing the cylindrical portion 2 is heavy in weight, and thus there is a problem that the strength is insufficient when an existing socket is used. Therefore, according to this embodiment, thermally-conductive resin is used as the material of the cylindrical portion 2, insulating resin is used as the material of the insulatingcylinderportion 10, andthe insulating cylinder portion 10 is molded integrally with the cylindrical portion 2 by insert molding. By forming the cylindrical portion 2 of thermally-conductive resin, the weight of the LED lamp 1 can be reducedmore greatly as comparedwith the case where the housing 35 is formed of a metal material such as aluminum or the like. Therefore, even when the LED lamp 1 is mounted as an alternative for an existing light bulb in an existing socket or an existing lampholder60, neitheraworknoramemberisrequiredtoreinforce the existing socket or the existing lamp holder 60 in order to support the weight of the LED lamp 1, and they can be directly used without any modification. Furthermore, the number of heat radiation fins 25 can be increased because the weight is reduced, so that the surface area increases and the heat radiation performance canbeefficientlyenhanced. Aresinmaterialhaving high thermal conductivity which has a coefficient of thermal - 19 conductivity of 2W/mK or more is preferably used as the thermally-conductive resin, and polycarbonate resin mixed with carbon fiber having high thermal conductivity (Raheama (registered trademark) produced by Teijin Limited in this embodiment) is preferably used. The insulating cylinder portion 10 is formed integrally with the cylindrical portion 2 by the insert molding using resin material, whereby the insulating cylinder portion 10 is firmly joined to the cylindrical portion 2. However, there is a risk that a crevice occurs in the joint face (mating face) of the insulating cylinder portion 10 due to secular change and the waterproof performance is lost. Therefore, as shown in Fig. 4, a fitting concavo-convex portion2Bis formed on the inner peripheral surfaceof theterminal 2Aof the cylindrical portion 2, and also a fitting concavo-convex portion 10B which is engagedly fitted to the fitting concavo-convex portion 2B is formed on the outer peripheral surface in the neighborhood of the end of the opening of the insulating cylinder portion 10, thereby constructing a so-called labyrinth-like fitting structure. Furthermore, the area of the joint portion increases and thus the joint strength is enhanced. Furthermore, a flange 10C with which the terminal 2A of the cylindrical portion 2 comes into contact is formed below the fitting concavo-convex portion 10B of the insulating cylinder portion 10, thereby preventing water invasion into the - 20 labyrinth-like fitting structure portion. Accordingly, even when a gap occurs on the insert molding face at the joint portion between the cylindrical portion 2 and the insulating cylinder portion 10 due to a crack or the like caused by secular change, thewaterproofperformance canbemaintainedbyhe labyrinth-like fitting structure portion and the flange 10C, and durability which is commensurate with the lifetime of the LED 15 can be obtained. The shape of the joint face between the terminal 2A of the cylindrical portion 2 and the opening end (insertion end) of the insulating cylinder portion 10 is not limited to the labyrinth-like shape, and any shape such as a wedge-like shape or the like may be adopted insofar as the waterproof performance and the joint strength can be enhanced. Furthermore, the joint between the cylindrical portion 2 and the insulating cylinder portion 10 may be established by assembly using screwing or the like insofar as requirements for various kinds of performance are satisfied. Next, the mount structure of the electrical circuit board in the cylindrical portion 2 will be described. As shown in Fig. 4, the electrical circuit board 8 is formed so as to extend from the tip 2C of the cylindrical portion 2 to the insulating cylinder portion 10, and configured to have a shape which is fitted to the internal shapes of the cylindrical portion 2 and the insulating cylinder 10.
- 21 That is, the diameter R of the upper portion of the cylindrical portion 2(Fig. 4) is set to be substantially equal to the lateral width of the upper portion of the electrical circuit board 8. Therefore, when the electrical circuit board 8 is inserted in the cylindrical portion 2, the electrical circuit board 8 is pinched by pinching portions 116 (Fig. 9) formed on the inner portion of the insulating cylinder portion 10, whereby the electrical circuit board 8 is fixed in the cylindrical portion 2. At thistime, when thecylindricalportion2 isminiaturized so that the diameter R of the upper portion thereof is reduced to the same level as the width of the upper portion of the electrical circuit board 8, the electrical circuit board 8 approaches to the cylindrical portion 2, and thus the electrical insulation performance between the cylindrical portion 2 and the electrical circuit board 8 is degraded. Therefore, an insulating sheet 28 is provided to be wound in the cylindrical portion 2 so as to surround the electrical circuit board 8, and the whole inner surface of the cylindrical portion 2 is covered by the insulating sheet 28 to enhance the insulation performance between the electrical circuit board 8 and the cylindrical portion 2. The insulating sheet 28 is formed of one belt-like sheet having flexibility and insulation properties, and the belt-like sheet is rolled once or at plural times (twice in this embodiment) to make the belt-like sheet be cylindrical. When the insulating - 22 sheet28 is insertedinto the cylindrical portion2, the insulating sheet 28 unrolls and expands in the cylindrical portion 2. At this time, the insulating sheet 28 is mounted on the inner surface of the cylindrical portion 2 by the unrolling force so as to cover the inner surface. As described above, the insulating sheet 28 is formed in a belt-like shape, inserted into the insertion opening 14 of the base plate 13 while rolled, and mounted in the cylindrical portion2 by the unrolling of the insulating sheet 28. Therefore, the insulating sheet 28 can be easily mounted in the cylindrical portion 2 so as to cover the whole inner surface of the cylindrical portion 2. Furthermore, a cut-out portion 28B is formed at the lower edge portion 28A (see Fig. 3) of the insulating sheet 28, and positioned to a projecting portion 14A (see Fig. 9) provided in the cylindrical portion 2, whereby both the end portions of the insulating sheet 28 which are overlapped with each other when the insulating sheet 28 is rolled can be positioned. Therefore, the cylindrical portion 2 can be furtherminiaturized. That is, when the overlapped portions of both the end portions of the insulating sheet 28 are inserted into the cylindrical portion2, underthe state that it is unknownwheretheseoverlapped portions are located, it would be necessary to provide a clearance between the edge portion of the electrical circuit board 8 and the cylindrical portion 2 in consideration of the sheet thickness - 23 corresponding to three rolls of the insulating sheet 28 (under twice rolling) at the overlap position of both the end portions of the insulating sheet 28. That is, in this case, the rolling frequency of the insulating sheet 28 is equal to twice, but the sheet thickness corresponding to three rolls of the insulating sheet 28 must be considered. However, when the overlap portions of both the end portions oftheinsulatingsheet28arepositionedbytheprojectingportion 14A so as to avoid the positions between the edge portion of the electrical circuit board 8 and the cylindrical portion 2, a clear may be provided between the edge portion of the electrical circuit board 8 and the cylindrical portion 2 in consideration of the sheet thickness corresponding to the rolling frequency of the insulting sheet 28. That is, in this case, when the rolling frequency of the insulating sheet 28 is equal to twice, the sheet thickness corresponding to two rolls of the insulating sheet 28 may be considered. Accordingly, the clearance can be more greatly reduced, and the cylindrical portion 2 can be further miniaturized. The electrical circuit board 8 inserted in the cylindrical portion 2 is fixed in the cylindrical portion 2 while the lower end side thereof is pinched by the pinching portions 116 (Fig. 9) as described above. At this time, the upper end portion 8C of the electrical circuit board 8 is pressed downwardly through a fixing bush 27 by the LED board 16 secured to the base plate - 24 13. Specifically, a heat generating part 8X which is provided to a power supply circuit to turn on LEDs 15 is mounted on the electrical circuit board 8 as shown in Fig. 4, and for example a metal heat sink 29 having high thermal conductivity is provided to the heat generatingpart 8X. In Figs. 3and4, reference numeral 29B represents a recess portion 29B for thinning. The surface of the heat generating part 8X or the heat sink 29 is coated with grease type thermally-conductive silicon filler to bring both the heat generating part 8X and the heat sink 29 into close contact with each other, whereby the heat generated from the heat generating part 8X is transferred to the heat sink 29. The fixing bush 27 is provided between the heat sink 29 and the cylindrical portion 2, and contact projections 27A are integrally provided to the upper end of the fixing bush 27. The contact projections 27A come into contact with the bottom surface of the LED board 16 to be pressed, so that the electrical circuit board 8 is pressed through the heat sink 29 and the heat generating part 8X. The fixing bush 27 is an elastic member having relatively high thermal conductivity, and the fixing bush 27 is pressed against the cylindrical portion 2 by the heat sink 29 to thereby construct a thermal conductive member 29D by the heat sink 29 and the fixing bush 27. The heat generated from the heat generating part 8X is transferred to the cylindrical portion - 25 2 through the thermal conductive member 29d, and radiated to the outside from the outer peripheral surface of the cylindrical portion 2. According to this embodiment, as shown in Figs. 3 and 4, the heat sink 29 is configured to extend to the neighborhood of the cylindrical portion 2, the fixing bush 27 formed in a cap-like shape is covered on the tip portion 29A of the heat sink 29, and the fixing bush 27 is pressed against the cylindrical portion 2. According to this construction, the thickness of the fixing bush 27 interposed between the heat sink 29 and the cylindrical portion 2 is reduced, so that heat is easily transferred from the heat sink 29 to the cylindrical portion 2. When the fixingbush27 is configuredtobe thin, the elastic force of the fixing bush 27 is reduced by the amount corresponding to the reduction of the thickness thereof, and sag occurs in the elastic circuit board 8 when the elastic circuit board 8 is pressed by the fixing bush 27 and the heat sink 29 when the elastic circuit board 8 is fixed. Therefore, it is desired that the fixing bush 27 is configured to have such cushion performance that the sag can be suppressed. Furthermore, when the amount of heat radiated from the surface of the heat sink 29 to the atmosphere around the cylindrical portion 2 is large, the heat stays in the cylindrical portion 2, and thus affects the other circuit parts. Therefore, with - 26 respect to the heat sink 29, a heat-radiation fin shape (concavo-convex shape) is formed at only the tip portion 29A covered by the fixing bush 27, and the cap-like shape of the fixing bush 27 is formed so as to intrude into and come into contact with the concavo-convex portion of the heat-radiation fin shape, whereby heat is more easily transferred from the heat-radiation fin shape of the tip portion 29A to the fixing bush 27 than that from the peripheral surface. Accordingly, the heat radiation from the heat sink 29 to the ambient of the cylindrical portion 2 can be suppressed, and the generated heat can be efficiently transferred to the cylindrical portion 2. As described above, the inner surface of the cylindrical portion 2 is covered by the insulating sheet 28, and a material having high thermal conductivity is used for the insulating sheet 28, so that the heat transfer from the fixing bush 27 to the cylindrical portion 2 is not disturbed by the insulating sheet 28. Asdescribedabove, the insulating sheet 28 has high thermal conductivity, and the fixing bush 27 as a thermally-conductive member for thermally connecting the circuit parts of the electrical circuit board 8 and the insulating sheet 28 is provided between each of the circuit parts of the electrical circuit board 8 and the insulating sheet 28, whereby both the insulation and the heat radiation for the electrical circuit board 8 can be - 27 enhanced. Furthermore, the above construction may be modified so that the insulation sheet 28 is provided with a cut-out portion by cutting out the insulation sheet 28 in a range which comes into contact with the fixing bush 27, whereby the fixing bush 27 is brought into direct contact with the cylindrical portion 2 through the cut-out portion. In this case, heat is directly transferred from the fixing bush 27 to the cylindrical portion 2 through no insulating sheet 28. In Fig. 3, reference numeral 270 representsasubstantially rod-like insulating bush comprising a rubber part formed of a silicon material, and it is mounted on the upper end portion 8C of the electrical circuit board 8 and pressed against the LED board 16 facing from the insertion opening 14. The voltage endurance performance can be enhanced by providing the insulating bush 270 between the electrical circuit board 8 and the LED board 16. Fig. 5 is a bottom view of the LED lamp 1 under the state that the annular waterproof packing 70 is detached from the LED lamp 1, Fig. 6 is a cross-sectional view taken along a line VI-VI, and Fig. 7 is a cross-sectional view taken along a line VII-VII. As described above, the housing 35 containing the cylindrical portion 2 and the base plate 13 is integrally provided with the plural heat radiation fins 25, thereby enhancing the heat radiation performance.
- 28 The heat radiation fins 25 are configured like thin plates, andmany heat radiation fins 25 are erected substantially radially around the axial line of the cylindrical portion 2 whew viewed from the back surface 13Aof the base plate 13. Fin root portions 25B as the root portions of the heat radiation fins 25 are joined tothebacksurface 13Aof thebaseplate 13, and theheat radiation fins 25, the cylindrical portion 2 and the base plate 13 are integrally molded from the thermal conductive resin described above by resin molding using a metal mold. As described above, the base plate 13 and the heat radiation fins 25 are integrally molded, whereby the heat resistance between the base plate 13 and each heat radiation fin 25 can be suppressed and the heat transfer amount to the heat radiation fins 25 can be increased to achieve high heat radiation performance. The heat radiation fins 25 extend downwards from the back surface 13A of the base plate 13 along the cylindrical portion 2, but a gap S is provided between each heat radiation fin 25 and the cylindrical portion 2 so that the heat radiation fins 25 are separated from the cylindrical portion 2 through the gaps S. Respective two adjacent heat radiation fins 25 are paired, and both the end portions at the cylindrical portion 2 side of each pair of heat radiation fins 25 are connected to each other through a joint portion 105, thereby forming each fin 101 having a substantially trapezoidal shape whose lower base is opened (or a substantially V-shape having a flat bottom) (hereinafter - 29 referred to as "open trapezoidal fin") in bottom view. Here, the upper base of the trapezoidal shape and the flat bottom of the V-shape correspond to the joint portion 105. These open trapezoidal fins 101 are formed integrally with one another. According to the open trapezoidal fins 101, an air flowing path F is formed between the cylindrical portion 2 and each joint portion 105 as shown in Fig. 5. Therefore, the outer peripheral surface of the cylindrical portion 2 is air-cooled and the electrical circuit board 8 mounted in the cylindrical portion 2 is cooled. Particularly, the heat of the heat generating part 8X of the electrical circuit board 8 is transferred to the cylindrical portion 2 through the fixing bush 27 and the heat sink 29 as described above. Therefore, the electrical circuit board 8 is efficiently cooled because the cylindrical portion 2 is cooled by air passing through the air flow paths F. In this embodiment, the adjacent two heat radiation fins 25are joinedtoeachother throughthe jointportion105. However, end portions at the cylindrical portion 2 side of adjacent three ormore heat radiation fins 25 maybe joined to one another through a joint portion 105. As shown in Fig. 5, a distributing fin 103 is provided between the adjacent open trapezoidal fins 101 (each fin corresponds to the pair of the heat radiation fins 25 joined at both the ends thereof through the joint portion 105) so that - 30 air flowing through the gap between these adjacent open trapezoidal fins 101 to the cylindrical portion 2 is distributed to each of the adjacent open trapezoidal fins 101 concerned. The distributing fins 103 extend from the back surface 13A of the base plate 13 along the cylindrical portion 2 like the heat radiation fins 25, anda gap is provided between each distributing fin 103 and the cylindrical portion 2 by a separating portion 91. The air stream passing through the gap between the open trapezoidal fins 101 isdistributedtoeachoftheopentrapezoidal fins 101 bythedistributing fin 103, wherebyunevenness of cooling on the outer peripheral surface of the cylindrical portion 2 can be suppressed, and the cylindrical portion 2 can be uniformly cooled. As shown in Fig. 1, the distributing fins 103 are configured to have a shorter length from the base plate 13 along the cylindrical portion 2 (for example, a shorter vertical length in the vertical direction in Fig. 1) than the heat radiation fins 25. Accordingly, air can flow over the distributing fin 103 between the open trapezoidal fins 101, so that the air distribution of the distributing fins 103 can be uniformly performed. The respective confronting heat radiation fins 25 of the adjacent open trapezoidal fins 101 are arranged in parallel to each other, and the distributing fin 103 is formed at the intermediate portion between the paired confronting heat - 31 radiation fins 25 in parallel to these confronting heat radiation fins 25. As shown in Fig. 5, the back surface 13A of the base plate 13 is further provided with short heat radiation fins 102 each located between the respective heat radiation fins 25 which are joined to each other by the joint portion 105 to constitute each trapezoidal heat radiation fin 101. The short heat radiation fins 102 are configured to have a shorter length from the back surface 13A of the base plate 13 along the cylindrical portion 2 (forexample, ashorterverticallengthintheverticaldirection of Fig. 1) than the heat radiation fins 25, and also have the same length as the distribution fins 103. The heat radiation of the base plate 13 is assisted by each short radiation fin 102, and LEDs 15 having higher output power can be mounted. Furthermore, the short heat radiation fins 102 are formed to be shorter than the heat radiation fins 25, and the end portions 102D at the cylindrical portion 2 side of the short radiation fins 102 are separated from the joint portions 105 through gaps Sa. Therefore, air flow in the open trapezoidal fins 101 is not disturbed, and thus the cooling performance of the open trapezoidal fins 101 which mainly carry out heat radiation is not disturbed. In addition, as shown in Fig. 5, outside annular fins 106 and inside annular fins 107 are formed on the back surface 13A of the base plate 13 as annular heat radiation fins which are - 32 arranged so as to surround the cylindrical portion 2. These outside annular fins 106 and inside annular fins 107 are configured to have a shorter length from the back surface 13A of the base plate 13 along the cylindrical portion 2 than the short heat radiation fins 102. The outside annular fins 106 and the inside annular fins 107 brings random nature to air streams in the open trapezoidal fins 101 and between the open trapezoidal fins 101, thereby enhancing the cooling performance. In addition, since the outside annular fins 106 and the inside annular fins 107 are short, when the LED lamp 1 is used in a posture that the light emitting portions 12 are located at lower positions than the base 3 (under so-called downward lighting), water or the like is prevented from being trapped in a space surrounded by the outside annular fin 106, the inside annular fin 107 and the open trapezoidal fin 101. The outside annular fins 106 are formed just below the outer-peripheral side light emitting portions 15A, the inside annular fins 107 are formed just below the inner-peripheral side light emitting portions 15B, and the outside and inside annular fins 106 and 107 are located at the outer peripheral side of the joint portions 105. The heat generated from LEDs 15 can be efficiently radiated and the base plate 13 can be reinforced by arranging the outside annular fins 106 and the inside annular fins 107 just below LEDs 15. In this embodiment, not only the heat radiation fins 25, - 33 but also the short heat radiation fins 102, the distributing fins 103, the outside annular fins 106 and the inside annular fins 107 which are shorter than the heat radiation fins 25 are provided on the back surface 13A of the base plate 13 as described above. At this time, the heat radiation performance could be enhanced by lengthening the respective fins. If so, it causes increase of the weight of the housing 35. Therefore, in this embodiment, onlytheheatradiationfins25oftheopentrapezoidal fins 101 which are in charge of most of heat radiation are lengthened, and the other fins are shortened, whereby the weight of the housing 35 is suppressed. However, as the fin length increases, the moment applied to the fin roots on the back surface 13A increases. Therefore, the heat radiation fins 25 are configured to be thicker than the other fins to enhance the strength thereof. Here, the surface of the housing 35 containing the base plate 13, the heat radiation fins 25, etc. is coated with coating material or chemicals to enhance weather resistance or design performance after the resin molding thereof. Conventional LED lamps are generally configured so that the heat radiation fins 25 radially extend from the cylindrical portion 2, and also the end portions at the base plate 13 side of the heat radiation fins 25 are connected to the back surface 13A of the base plate 13. Therefore, there is a problem that in the above coating process, the coating material or the like hardly intrudes into - 34 the corner portions of each joint portion between the base plate 13 and each of the cylindrical portion 2 and the heat radiation fins 25, and also the coating material or the like droops in front of the fins when the amount of the coating material or the like is increased. Therefore, it is required in the coating process to coat the coating material or the like little by little while dividing the coating process into plural steps. Therefore, the coating frequency increases, which causes increase of the cost. On the other hand, in the LED lamp 1 of this embodiment, the separating portion 91 for separating the heat radiation fin 25 and the cylindrical portion 2 from each other is provided over the area from the fin root portion 25B as the root portion (at the upper position in the vertical direction) of each heat radiation fin 25 (as a joint portion to the base plate 13) to the fin tip 25A (at the lower position in the vertical direction) of the heat radiation fin 25 to provide the gap S between each heat radiation fin 25 and the cylindrical portion 2. Accordingly, in the coating process of coating the housing 35, no pool of liquid occurs between each heat radiation fin 25 and the cylindricalportion2. Therefore, theamountof liquid to be coated per once can be increased to reduce the coating frequency, and the coating material can be easily and uniformly coated on the housing 35. Particularly, the coating material goes around the cylindrical portion 2 through the separating - 35 portions 91 by spraying the coating material through a spray or the like, so that the coating material can be coated evenly in a broad range by only one coating operation.. Furthermore, the weight of the housing 35 can be reduced by providing the separating portions 91, and the cost of the material can be suppressed. Furthermore, rain water or the like can be prevented from collecting between the heat radiation fin 25 and the cylindrical portion 2 when the LED lamp 1 is used. In addition, with respect to the short heat radiation fins 102 provided in the open trapezoidal fins 101, the gap Sa is provided between each short heat radiation fin 102 and the joint portion 105. Accordingly, uneven (irregular) coating of the coating material can be also prevented from the open trapezoidal fins 101. As shown in Fig. 1, the open trapezoidal fins 101 (the heat radiation fins 25), the short heat radiation fins 102 and the distributing fins 103 are configured to be substantially fan-shaped inside view so as to draw a moderate arc in the direction from the back surface 13A of the base plate 13 (Fig. 2) to the edge portion 66 of the opening of the holder housing 62, 'the lengths of the open trapezoidal fins 101 (the heat radiation fins 25), the short heat radiation fins 102 and the distributing fins 103 which extend in the axial direction of the cylindrical portion 2 (that is, the lengths thereof along the cylindrical portion 2) are gradually reduced from the inner peripheral side - 36 (the cylindrical portion 2 side) to the outer peripheral side. Asdescribedabove, theheatradiationfins25, etc. areconfigured to be substantially fan-shaped in side view, whereby sense of unity between the lamp holder 60 and the LED lamp 1 can be enhanced when the LED lamp 1 is mounted in the lamp holder 60, thereby enhancing the design performance. As shown in Fig. 6, the fin tips 101Aof the open trapezoidal fins 101 are formed horizontally (vertically to the axial line ofthe cylindricalportion2), and theuppersurfaceoftheannular waterproof packing 70 mounted on the cylindrical portion 2 comes into contact with the fin tips 101A. As shown in Fig. 7, the base plate 13 is configured to be gradually thinner from the inner peripheral portion 13B connected to the cylindrical portion 2 to the outer peripheral portion 13C. Specifically, the fixing surface 13D of the base plate 13 to which the LED board 16 is fixed is formed to be vertical to the axial line of the cylindrical portion 2, and the back surface 13A of the base plate 13 on which the heat radiation fins 25 are formed is configured as a taper surface so that the thickness thereof is smaller over the whole surface thereof as the position thereof shifts to the outer peripheral side. The base plate 13 has lower heat resistance to the heat radiation fins 25 as the position thereof shifts to the outer peripheral portion13Csidewhichissmallerinplatethickness. Furthermore, the inner peripheral portion 13B of the base plate 13 is configured - 37 to be thicker, and thus has high rigidity. Therefore, the fixing surface 13D can be prevented from warping and the flatness of the fixing surface 13D can be enhanced. Fig. 8 is a partially enlarged plan view of the open trapezoidal fin 101. As shown in Fig. 8, the heat radiation fin 25 constituting the open trapezoidal fin 101 has a large thickness portion 110 at which the plate thickness of the fin root portion 25B is substantially equal to the plate thickness of the joint portion 105, anda smallthicknessportion lllatwhichtheplate thickness of the fin root portion 25B is gradually smaller from the end portion of the large thickness portion 110 to the tip side of the outer peripheral side of the heat radiation fin 25. The boundaryportion 110A (Fig. 8) betweenthe large thicknessportion 110 and the small thickness portion 111 is located between the outside annular fin 106 and the inside annular fin 107. As described above, the fin root portions 25B of the heat radiation fin 25 constituting the open trapezoidal fin 101 are configured to be thinner in plate thickness toward the outer peripheral side, so that the open trapezoidal fin 101 is lighter in weight toward the outer peripheral side. In this embodiment, as described above, the open trapezoidal fins 101 are configured to be substantially fan-shaped in side view so as to draw a moderate arc, and the extension length of the open trapezoidal fin 101 extending in - 38 the axial direction of the cylindrical portion 2 is gradually reduced from the inner peripheral side to the outer peripheral side. Therefore, whenexternalforceactsontheopentrapezoidal fin 101, bending moment applied to the fin root portion 25B of the open trapezoidal fin 101 is smaller as the applied position shifts to the outer peripheral side at which the length in the axial direction of the open trapezoidal fin 101 is smaller. Therefore, the plate thickness of the fin root portion 25B of the heat radiation fin 25 constituting the open trapezoidal fin 101 is reduced to be smaller toward the outer peripheral side in conformity with the bending moment. Furthermore, in order to prevent occurrence of sink (shrinkage) onthe fixing surface l3Dinthe resinmoldingprocess, it may be considered that the thickness of the base plate 13 is larger than the plate thickness of the open trapezoidal fin 10lat the finrootportion25B. In thiscase, theheat resistance from the base plate 13 to the open trapezoidal fin 101 increases. However, in this embodiment, the base plate 13 is configured to be thinner toward the outer peripheral portion 13C side in conformity with the plat thickness of the fin root portion 25B of the heat radiation fin 25 which is smaller toward the outer peripheralside. Therefore, sinkcanbepreventedfromoccurring on the fixing surface 13D in the resin molding process with enhancing the heat radiation performance of the base plate 13. By preventing occurrence of sink of the fixing surface 13D, the - 39 flatness of the fixing surface 13D is enhanced, and the adhesiveness between the fixing surface 13D and the LED board 16 is enhanced, so that the heat radiation performance of the base plate 13 can be enhanced. More specifically, when sink occurs in the fin root portion 25B of each open trapezoidal fin 101, a gap occurs between the fixing surface 13D and the LED board 16 at this portion. However, by preventing occurrence of sink, the fixing surface 13D and the LED board 16 can be brought into close contact with each other, so that the heat radiation performance can be enhanced. Furthermore, the base plate 13 and the open trapezoidal fins 101 are configured to be thinner toward the outer peripheral side, and thus the weight of the housing 35 can be reduced. Still furthermore, the base plate 13 and the open trapezoidal fins 101 are configured to be thinner toward the outer peripheral side, and the heat radiation performance at the outer peripheral side is enhanced. Therefore, heat of the outer-peripheral side light emitting portions 15A whose heat generation amount is larger than that of the inner-peripheral side light emitting portions 15B can be efficiently radiated. Even when the base plate 13 and the open trapezoidal fins 101 are manufactured by aluminum die cast, sink can be suppressed by adopting the construction of this embodiment. As shown in Figs. 6 to 8, the thicknesses of the heat radiation fins 25 constituting the open trapezoidal fins 101, - 40 the short heat radiation fins 25, the distributing fins 103, the outside annular fins 106 and the inside annular fins 107 are set to be gradually smaller in the axial direction from the fin root portions 25B to the end of the base 3 side. Therefore, the thickness of each fin acts as a releasing taper, and when the housing 35 is molded by a metal mold, the housing 35 can be easily separated from the metal mold in the axial direction. Furthermore, groove portions 115 are formed at both the sides of the fin root portion 25B of each of the heat radiation fins 25 constituting the open trapezoidal fins 101, the short heat radiation fins 102, the distributing fins 103, the outside annular fins 106 and the inside annular fins 107. The groove portions 115 are formed over the whole length of each fin. The shrinkage range of the resin in the neighborhood of the fin root portions 25B can be narrowed due to this groove portion 115, so that sink occurring on the fixing surface 13D canbe suppressed and at the same time the surface area of the base plate 13 can be increased. As shown in Figs. 1 to 4, the annular waterproof packing 70 is formed in a substantially truncated conical shape in side view (a substantially trapezoidal shape in section) so as to be continuous with arcs corresponding to the outer shapes of the heat radiation fins 25, the contour shape constructed by the heat radiation fins 25 and the annular waterproof packing 70 is set to be substantially equal to the contour shape of an - 41 existing glass bulb. Accordingly, even when the LED lamp 1 is used in place of the existing light bulb, a trouble caused by the difference in shape can be prevented. Here, a resin material mixed with carbon fiber having high thermal conductivity (hereinafter referred to as "thermal conductive fiber") is used as the material of the cylindrical portion 2. It is known that anisotropy occurs in thermal conductivity in accordance with orientation of the thermal conductive fiber. In this embodiment, the thermal conductive fiber is oriented so as to increase the thermal conductivity from the cylindrical portion 2 and the base plate 13 to the heat radiation fins 25, thereby enhancing the heat radiation performance of the cylindrical portion 2. The orientation of the thermal conductive fiber is controlled on the basis of the resin injecting direction in a resin injection molding process. Next, a structure of passing lead wires 21A and 21B at the terminal 10A of the insulating cylindrical portion 10 will be described. Fig. 9 is a plan view of the housing 35 which is taken from the base plate 13 side. As shown in Fig. 9, a pair of pinching portions 116 for pinching and supporting the edge portions of the electrical circuit board 8 are provided on the inner peripheral surface of the insulating cylinder portion 10 so as to project therefrom.
- 42 The pinching portions 116 are arranged to be slightly displaced from the center of the insulating cylinder portion 10 and confront each other, and the electrical circuit board 8 is supported to be slightly displaced from the center of the insulating cylinder portion 10 so that the plate surface thereof is in parallel to the axial line of the insulating cylinder portion 10. Fig. 10 is a cross-sectional view taken along a line X-X of Fig. 9. As shown inEFigs. 4, 9and 10, the insulting cylinderportion 10 is closed by a bag portion 120 formed at the terminal 10A. Specifically, the bag portion 120 has a plate portion 121 provided so as to close the terminal 10A at the inside of the end face of the terminal 10A, and a pair of projecting portions 122A and 122B obtained by projecting a part of the plate portion 121 to the eyelet side 7. The projecting portions 122A and 122B are surrounded by a cylinder portion 123 formed at the end of the terminal 10A, and an inside portion of the cylinder portion 123 at which the projecting portion 122A and 122B are not formed serves as a recess portion 124 which is inwardly concaved from the end face 123A of the cylinder portion 123. The projecting portion 122A and 122B project to be closer to the eyelet 7 side than the end face 123A of the cylinder portion 123, and they are formed to be tapered to the tips thereof. The end of the eyelet side 7 of the housing 35 corresponds to the tips of the projecting portions 122A and 122B.
- 43 Wire holes 125A and 125B as through-holes penetrating through the projecting portions 122A and 122B are formed at the tip portions of the projecting portions 122A and 122B, and the lead wires 21A and 21B extending from the electrical circuit board 8 pass through the wire holes 125A and 125B and extend to the base 3 side. The wire holes 125A and 125B are arranged on the center line of the insulating cylinder portion 10 parallel to the electrical circuit board 8 in plan view. Large-diameter portions 129 are formed at the ends of the wire holes 125A and 125B, and the lead wires 21A and 21B are easily bent at the large-diameter portions 129. The projecting portions 122A and 122B are formed at the inner surface side of the bag portion 120 so that the center portion of the plate portion 121 remains, whereby a partition wall 126 projecting to the light emitting portion 12 side is formed by the plate portion 121. The inner space of the terminal 10A which is substantially cylindrical in section is substantially bisected by the partition wall 126. The partition wall 126 is disposed so as to pass through the center of the insulating cylinderportion 10 andbe substantially perpendicular to the plate surface of the electrical circuit board 8. As shown in Fig. 9, the lead wires 21A and 21B are led out frompositions corresponding toboth the sides of thepartition wall 126 at the lower side of the electrical circuit board 8. A pair of introducing portions 127A and 127B for leading - 44 the lead wires 21A and 21B to the wire holes 125A and 125B are formed at the inside of the projecting portions 122A and 122B. The introducing portions 127A and 127B are formed in a conical shape(funnel-shape) tapered to the wire holes 125A and 125B at the tip thereof, so that the introducing portions 127A and 127B can surely guide the lead wires 21A and 21B to the wire holes 125a and 125B. Furthermore, the inner space of the terminal 10A is substantially bisected by the partition wall 126, and occupied by the introducing portions 127A and 127B. Therefore, the lead wires 21A and 21B necessarily abut against the introducing portions 127A and 127B, so that the lead wires 21A and 21B can be surely guided to the wire holes 125A and 125B. In the assembling process, the electrical circuit board 8 is inserted through the insulating cylinder portion 10 to the eyelet 7 side along the pinching portions 116. In connection with the insertion of the electrical circuit board 8, the lead wires 21A and 21B at the lower portion of the electrical circuit board 8 come into contact with the introducing portions 127A and 127B which are partitioned by the partition wall 126 and located below the lead wires 21A and 21B, and surely led to the wire holes 125A and 125B while guided by the funnel-shaped introducing portions 127A and 127B. As shown in Fig. 4, the lead wire 21A drawn out from the wire hole 125A is passed through the inside of the base 3 and connected to the eyelet 7. The lead wire 21B drawn out from the - 45 wire hole 125B is bent to the outside at the terminal 10A of the insulating cylinder 10, extends along the outer surface of the insulating cylinder portion 10 and then is connected to the shell 5. As described above, the wire holes 125A and 125B through which the lead wires 21A and 21B are respectively drawn out are provided in front of the position at which the lead wire 21B is outwardly bent. Therefore, the lead wires 21A and 21B can be prevented from intertangling with each other and thus short-circuited to each other. Furthermore, by providing the introducing portions 127A and 127B, the lead wires 21A and 21B can be simply passed through the wire holes 125A and 125B. Therefore, even when the wire holes 125A and 125B are formed so that the diameter thereof is substantially equal to that of the lead wires 21A and 21B and thus no gap occurs therebetween, these lead wires 21A and 21B can be simply passed through the wire holes 125A and 125B. Fig. 11 is an enlarged view of the terminal 10A of the insulating cylinder portion 10. A screw portion 33 (locking portion) which is engaged with the inner peripheral surface of the shell 5 to lock the base 3 is formed on the outer peripheral surface of the terminal 10A of the insulating cylinder portion 10. A wire groove 34 (groove portion) extending in the axial direction of the insulating cylinder portion 10 is formed on the outer peripheral surface - 46 of the terminal 10A, and the wire groove 34 is provided to be engraved in a part of the screw portion 33. The lead wire 21B which bends and extends outwards from the inside of the insulating cylinder 10 extends to the cylinder portion 2 side while embedded in the wire groove 34. That is, under the state that the shell 5 is secured to the insulating cylinder 10, the lead wire 21 passes through the wire groove 34 at the inside of the shell 5, and joined to the outer peripheral surface of the shell 5 in the neighborhood of the opening end of the shell 5. The end 34A of the wire groove 34 is located at the end face 123A of the cylinder portion 123, and the projecting portions 122A and 122B projects to the eyelet 7 side at the outside of the end 34A of the wire groove 34. Furthermore, the wire groove 34 through which the lead wire 21B passes links to the inside of the insulating cylinder 10, and the eyelet 7 and the cylinder portion 2 intercommunicate with each other through the wire holes 125A and 125B in the insulating cylinder 10. Therefore, air can get into/out of the cylinder portion 2 through the wire groove 34 and the wire holes 125Aand125B, therebypreventingdew condensation inthe cylinder portion 2. When the base 3 is secured to the insulating cylinder 10, the shell 5 is swaged from the outer peripheral side of the insulating cylinder 10 and fixed to the insulating cylinder 10 under the state that the shell 5 is engaged with the screw portion - 47 33 of the insulating cylinder 10. A pair of prepared holes 56 for swage of the base 3 are provided in the side surface of the insulating cylinder 10. The shell 5 of the base 3 is swaged at the positions corresponding to the prepared holes 56, whereby the shell 5 is deformed so as to intrude into the prepared holes 56, whereby the deformation amount of the shell 5 increases, and the strength of the swaging portions can be enhanced. When the LED lamp 1 is installed in a downward lighting state under which the LED lamp 1 lights downwards, the bag portion 120 constitutes the upper surface of the housing 35. In this embodiment, the bag portion 120 projects to the upper side of the end face 123A of the insulating cylinder portion 10 under the downward lighting state, and the wire holes 125A and 125B are located at the upper side of the end face 123A. Therefore, even when water invades into the upper surface portion of the housing 35 due to dew condensation, rain water or the like, these water can be prevented from invading from the wire holes 125A and 125B into the housing 35. Furthermore, when the invasion amount of water is large, the water is pooled in the recess portion 124 of the upper surface portion. However, the wire holes 125A and 125B are located above the end face 123A, so that water can be prevented from invading into the wire holes 125A and 125B. Furthermore, the wire holes 125A and 125B are located at higherpositions thantheend34Aofthewiregroove3 4 . Therefore, - 48 even when water invades along the wire groove 34 into the upper surface portion of the housing 35, the water can be prevented from invading into the wire holes 125A and 125B. Therefore, air can get into/out of the cylindrical portion 2 through the wire groove 34, whereby water can be prevented from the wire holes 125A and 125B into the housing 35 with preventing dew condensation in the housing 35. Next, there will be described an anti-drop structure for the LED lamp 1 suitably used when the LED lamp 1 is installed in a so-called downward lighting state under which the LED lamp 1 is set up at a high place and lights an illumination target object such as an advertizing display or a wall surface which is disposed at the vertical lower side, an indoor or the like. Fig. 12 is a diagram showing the anti-drop structure for the LED lamp 1. As shown in Figs. 1 to 3, Fig. 5 and Fig. 12, the LED lamp 1 has a pair of metal pins 130 joined to the adjacent open trapezoidal fins 101 (two pairs of adjacent open trapezoidal fins 101 in this embodiment), and a pair of anti-drop wires 131 joined to the pins 130. Each of the anti-drop wires 131 is connected to a metal band 133 fixed to the lamp holder 60, whereby the LED lamp 1 is joined to the lamp holder 60 through the anti-drop wire 131. Any rod-like or string-like member may be used as the anti-drop wire 131 insofar as it functions as a support member for supporting the LED lamp 1.
- 49 As shown in Fig. 5, each pin 130 is bridged between the pair of adjacent open trapezoidal fins 101 between which the distributing fin 103 is sandwiched. Specifically, each pin 130 is bridged between the heat radiation fins 25 arranged substantially in parallel so as to penetrate through the heat radiation fins 25 substantially perpendicularly to the surface of the fin 25. As described above, the pins 130 are joined to plural heat radiation fins 25, whereby the pins 130 are firmly fixed. Each of the heat radiation fins 25 through which the pins 130 penetrate is provided with a support hole 134 at the intermediate portion of a portion thereof which extends in the radial direction of the base plate 13, and both the end portions of eachpin 130 are insertedthrough the support holes 134, whereby the pins 130 is fixed to the heat radiation fins 25. Each pin 130 is fixed to the intermediate portion in the height direction of each heat radiation fin 25, and located below the distributing fin 103. Each pin 130 has a flange portion 130A at one end thereof, and the pin 130 is inserted through the support hole 134 of one of the heat radiation fins 25 to be bridged by the pin 130 concerned while the flange portion 130A thereof abuts against the one heat radiation fin 25 concerned, and the other end of the pin 25 concerned is inserted through the support hole 134 of the other heat radiation fin 25 and fitted in a fixing ring 130B so that - 50 the pin 130 is fixed to the heat radiation fin 25 by the fixing ring 130B. In this embodiment, the heat radiation fins 25 to be bridged by the pins 130 are arranged substantially in parallel to each other. Therefore, the support holes 134 can be easily formed in the heat radiation fins 25 by a machine work or the like for forming through-holes penetrating through the heat radiation fins 25 after the resin molding process. The support holes 134 may be formed by a boring mechanism provided to the metal mold used for the resin molding of the housing 35. In this case, the support holes 134 can be easily formed because the heat radiation fins 25 are arranged substantially in parallel. Furthermore, the pair of pins 130 are provided so as to confront each other through the cylindrical portion 2. The anti-drop wire 131 is constructed by crooking both the ends of a wire in a ring-like shape and swaging the crooked ends of the wire with swaging portions 131D, and has a pin joint portion 131A to be hooked to the pin 130 at one end thereof, and a band joint portion 131B to be joined to the band 133 at the other end thereof. The ring-shaped portion of the pin joint portion 131A has a hook 131C to be hooked to the pin 130. Figs. 13A and 13B show the band 133, wherein Fig. 13A is a plan view of the band 133, and Fig. 13B is a perspective view showing the state that the anti-drop wire 131 is secured. As shown in Fig. 13, the band 133 has a C type ring portion - 51 135 obtained by bending a band-like plate annularly (like a ring), an adjusting portion 136 provided to an open end of the C type ring portion 135, and a pair of wire joint portions 137 formed on the outer peripheral surface of the C type ring portion 135 so as to project outwards from the outer peripheral surface. The adjusting portion 136 has a nut portion 136A formed at one end of the C type ring portion 135, a hole portion 136B formed at the other end of the C type ring portion 135, and a bolt 136C screwed to the nut portion 136A. The diameter of the C type ring portion 135 of the band 133 can be changed by fastening the bolt 136C inserted through the hole portion 136B to the nut portion 136A, whereby the constriction force of the band 133 to the lamp holder 60 can be adjusted. A hole 137A to which the band joint portion 131B of the anti-drop wire 131 is joined is formed in the wire joint portion 137, and the anti-drop wire 131 is turnable around the wire joint portion 137. The wire joint portions 137 are provided so as to confronteachotherinconnectionwiththepins130. Furthermore, the wire joint portions 137 are arranged so that the anti-drop wires 131 are substantially parallel to the axial line of the LED lamp 1 under the state that the anti-drop wires 131 are joined to the pins 130. Theband 133 is wound and fixed around a band winding portion 60C provided on the outer peripheral surface in the neighborhood of the tip60Bof the lampholder 60. Astepportion60Dprojecting - 52 outwards is formed at the tip 60B side of the band winding portion 60C. When the band 133 moves to slip out of the lamp holder 60, the band 133 abuts against the step portion 60D, whereby the band 133 is prevented from slipping out in the axial direction of the lamp holder 60. When the LED lamp 1 is secured to the lamp holder 60, the hook 131C of each anti-drop wire 131 is joined to each pin 130 of the LED lamp 1 to connect the band 133 to the LED lamp 1. Subsequently, the band 133 is kept under an expanded state, the LED lamp 1 is inserted into the lamp holder 60 from the base 3 side while the lamp holder 60 is passed through the band 133, and the band 133 is temporarily fixed to the band winding portion 60C of the lamp holder 60. Under this state, the constriction force of the band 133 is loosened by the adjusting portion 136, and the diameter thereof is set so that the band 133 is rotatable on the outer peripheral surface of the lamp holder 60, but it does not detach from the lamp holder 60. Subsequently, the base 3 of the LED lamp 1 is screwed to the socket 65 by rotating the LED lamp 1. At this time, the band 133 rotates together with the LED lamp 1. As described above, the LED lamp 1 is screwed to the lamp holder 60 under the state that the LED lamp 1 is connected to the lamp holder 60 through the anti-drop wires 131 and the band 133. Therefore, when the LED lamp 1 is secured to the lamp holder 60, the LED lamp 1 can be suppressed fromdropping off the lamp holder 60. Furthermore, - 53 when the LED lamp 1 is detached from the lamp holder 60, the LED lamp 1 can be prevented from dropping by rotating the LED lamp 1 while the band 133 is loosened. After the LED lamp 1 is screwed to the socket 65, the band 133 is completely constricted by the adjusting portion 136, whereby the band 133 is fixed to a predetermined position of the band winding portion 60C of the lamp holder 60. Accordingly, the LED lamp 1 is fixed to the lamp holder 60 through the pair of anti-drop wires 131, thereby preventing the LED lamp 1 from dropping off. That is, even when the engagement between the base 3 and the socket 65 is released from any cause, the LED lamp 1 can be prevented from dropping off because it is fixed to the lamp holder 60 by the anti-drop wires 131. Tension is applied to the anti-drop wires 131 by adjusting the position at which the band 133 is fixed, whereby the annular waterproof packing 70 is compressed between the open trapezoidal fin 101 and the tip 60B of the lamp holder 60. Therefore, even when vibration acts, occurrence of a gap between the annular waterproof packing 70 and the lamp holder 60 can be prevented, and the waterproof performance can be enhanced. Furthermore, the weight of the LED lamp 1 is shared by the anti-drop wires 131 and the socket 65, and thus the load acting on the socket 65 is reduced. Therefore, the socket 65 can be prevented from being deformed or damaged when vibration or the like acts.
- 54 Furthermore, the LED lamp 1 is supported by the anti-drop wires 131 which confront each other through the cylindrical portion 2. Therefore, even when the engagement between the base 3 and the socket 65 is released, the LED lamp 1 can be prevented from dropping out of the lamp holder 60. For example, when the above construction is modified so that the LED lamp 1 is supported by only one anti-drop wire 131, the dropping of the LED lamp 1 can be prevented, but the anti-drop wire 131 and the LED lamp 1 may turn around the pin 130, so that the LED lamp 1 drops out of the lamp holder 60. This embodiment has been described on the assumption that a pair of anti-drop wires 131 are provided. However, this embodiment may be modified so that only one anti-drop wire 131 is provided in consideration of the weight of the LED lamp 1 or an estimated load or the like to be imposed and the LED lamp 1 is supported by only one anti-drop wire 131. Furthermore, in this embodiment, the pin 130 bridged between two heat radiation fins 25 is provided as a connection member. However, the present invention is not limited to this embodiment. The connection member maybe configured to be bridged between two or more heat radiation fins 25. For example, the connectionmembermaybe a ring-shapedmemberwhichmakes a circuit of the cylindrical portion 2 while passing through the support holes 134 formed in all (twelve)heat radiation fins 25, and the anti-drop wire 131 may be connected to this connection member.
- 55 In place of the rod-like pin 130, a string-like wire may be used as the connection member. Furthermore, the present invention is not limited to the construction that the anti-drop wire 131 is secured to the lamp holder 60 by using the band 133. For example, one end side of a string-like anti-drop wire 131 is wound around the lamp holder 60 or the like to fix the one end side of the string-like anti-drop wire 131 to the lamp holder 60, and the other end thereof is fixedtothepin130orthelikeof theLEDlampl, therebypreventing drop of the LED lamp 1. Here, since the LED lamp 1 is heavier than a normal incandescent light bulb or the like, the load imposed on the socket 65 and the base 3 increases. Therefore, when the LED lamp 1 is used while mounted on a lamp holder 60 having an existing socket 65 which is designed for an incandescent light bulb, for example, vibration is applied to the LED lamp 1 from vehicles, etc. running on a road. When the effect of the vibration is accumulatively applied to the socket 65 and the base 3, the socket 65, the base 3, etc. are damaged, so that the LED lamp 1 may drop out of the lamp holder 60 with high probability. In this embodiment, as described above, the two anti-drop wires 131 extending from the lamp holder 60 are connected to the pins 130 of the LED lamp 1 at two positions. Therefore, even when the LED lamp 1 drops out of the socket 65, the drop of the LED lamp 1 can be prevented.
- 56 However, as described above, the dead weight of the LED lamp 1 is larger than the incandescent light bulb, etc. Therefore, in a case where the LED lamp 1 dropped out of the socket 65 greatly swings when suspended by the anti-drop wire 131, the LED lamp 1 may collide against an illumination target such as a billboard or the like and thus suffer a great impact, so that the LED lamp 1 is damaged by the impact. Therefore, according to this embodiment, in order to suppress the swing width of the LED lamp 1 when the LED lamp 1 drops out of the socket 65, the support holes 134 for supporting the pins 130 are provided to be nearer to the base 3 than the center-of-gravity position Gx of the dead weight of the LED lamp 1 between the light emitting portion 12 and the base 3. Fig. 14 is a diagram showing the positional relationship between the center-of-gravity position Gx of the dead weight of the LED lamp 1 and the support hole 134, wherein the upper stage of Fig. 14 shows a state that the LED lamp 1 is installed and the lower stage of Fig. 14 shows a state that the LED lamp 1 drops out. The center-of-gravity position Gx of the dead weight corresponds to the position corresponding to the center of gravity of the dead weight of the LED lamp 1. When there is any accessory such as the annular waterproof packing 70 or the like which is kept to be mounted on the LED lamp 1 when the LED lamp 1 drops out of the socket 65, the total weight containing the weight - 57 of the accessory concerned is adopted as the dead weight of the LED lamp 1. When the LED lamp 1 is used under the downward lighting state, as shown at the upper stage of Fig. 14, the LED lamp 1 is set up so that the base 3 is mounted in the socket 65 in such a posture that the light emitting portion 12 of the LED lamp 1 faces a vertical lower side and the base 3 is located at a vertically higher position than the light emitting portion 12. When the base 3 drops out of the socket 65 under this setup state as shown at the lower stage of Fig. 14, the support hole 134 is turned as a supporting point so that the center-of-gravity position Gx of the dead weight is located vertically just below the support hole 134 to which the anti-drop wire 131 is connected. In the LED lamp 1 of this embodiment, the support hole 134 is provided to be nearer to the base 3 than the center-of-gravity position Gx of the dead weight, and the center-of-gravity position Gx of the dead weight has been already located at a vertically lower side of the support hole 134 under the setup state. Therefore, the turn (swing) amount of the LED lamp 1 under the drop-out state corresponds to the level of the displacement amount in the horizontal direction between the center-of-gravity position Gx of the dead weight and the support hole 134, so that the swing width of the LED lamp 1 caused by the turning can be suppressed to a relatively small value. Fig. 15 is a diagram showing the positional relationship - 58 between the center-of-gravity position Gx of the dead weight of the LED lamp 1, wherein the upper stage of Fig. 15 shows the setup state of the LED lamp and the lower stage of Fig. 15B shows the dropout state of the LED lamp. In the case of the LED lamp 1 in which the support hole 134 is disposed to be nearer to the light emitting portion 12 than the center-of-gravity position Gx of the dead weight of the LED lamp 1 as shown at the upper stage of Fig. 15, when the base 3 drops out of the socket 65, the LED lamp 1 greatly turns (swings) around the support hole 134 as a supporting point so that the center-of-gravity position Gx of the dead weight located at a vertically upper side of the support hole 134 moves to the vertically just lower side of the supporthole134, andtheswingwidthoftheLEDlamplisrelatively large in connection with the turn (swing) of the LED lamp 1. That is, as in the case of this embodiment, the support hole 134 is provided to be nearer to the base 3 than the center-of-gravity position Gx of the dead weight, whereby the turn (swing) amount of the LED lamp 1 when the base 3 drops out of the socket 65 can be reduced. Therefore, the swing width of the LED lamp 1 can be suppressed to a relatively small value. As a result, even when the LED lamp 1 is loosened and temporarily drops out of the socket 65, the LED lamp 1 can be avoided from impinging against an illumination target such as a billboard or the like because the swing width of the LED lamp 1 under the drop-out state is small. Furthermore, even when the - 59 LED lamp 1 impinges against the illumination target, the impact at that time can be suppressed, and thus the LED lamp 1 can be prevented from being damaged. As described above, the impact applied to the support hole 134 is suppressed. Therefore, the housing 35 of the LED lamp 1 may be formed of resin material which will be liable to be lower in strength than metal material after the molding process. Accordingly, even when the connection portion (the support hole 134 in this embodiment) of the anti-drop wire 131 is formed integrally with the housing 35, the connection portion can be prevented from being damaged while the weight of the housing is reduced. Furthermore, in this embodiment, in order to locate the support hole 134 at a position nearer to the base 3 side than the center-of-gravity position Gx of the dead weight when the support hole 134 is provided to the heat radiation fin 25, weight balance is designed so that the center-of-gravity position Gx of the dead weight is located to be nearer to the light emitting portion 12 side than the support hole 134. Accordingly, the support holes 134 can be provided to the heat radiation fins 25, the support holes 134 can be prevented from intruding into the lamp holder 60 when the LED lamp 1 is mounted in the lamp holder 60, and the anti-drop wire 131 can be simply connected to the support hole 134. In this embodiment, the support hole 134 provided to the - 60 heat radiation fin 25 is exemplified as the connection portion of the anti-drop wire 131. However, the present invention is not limited to the support hole 134, and any structure may be adopted insofar as the anti-drop wire 131 is connectable to the structure. Any member such as a rod-like or string-like member may be adopted as the anti-drop wire 131 insofar as it may be a support member whose one end is connected and fixed to a stable place of a building, the lamp holder 60 or the like to support the LED lamp 1. Next, a structure for fixing the globe 22 to the base plate 13 will be described. A screwing structure for fixing the globe 22 to the base plate 13 by screwing the globe 22 in the base plate 13 is generally used as the fixing structure of the globe 22. However, with respect to the screwing structure, the globe 22 rotates at any number of times when the globe 22 is fixed to the base plate 13, and thus it has a problem that the rotation of the globe 22 twists an 0-ring 26 and causes distortion in the O-ring 26, so that the sealing performance is lowered. Therefore, according to this embodiment, the fitting structure between a projection and a groove is adopted as the fixingstructureoftheglobe22inplaceofthescrewingstructure, thereby suppressing the distortion of the O-ring 26 caused by the fixing of the globe 22.
- 61 Fig. 16 is a cross-sectional view of the base plate 13. As shown in Figs. 16 and 1, the base plate 13 is formed in a tray-like shape having a side wall 19 at the edge thereof. A step portion 200 of one step is formed on the whole periphery of the inner peripheral surface (inner surface) of the side wall 19. The step portion 200 is formed by projecting a lower end 19B side of the side wall 19 inwardly as compared with the upper end 19A side of the side wall 19 so that the lower end 19B side is larger in thickness than the upper end 19A side. Plural guide andholdgrooves 201 are formedona lower-stageperipheral surface 200A as the peripheral surface of the lower end 19B side of the step portion 200. As shown in Fig. 3, the edge portion 22A of the globe 22 extends vertically in a substantially cylindrical shape, and plural projections 202 projecting outwards are formed on the outer peripheral surface (outer surface) of the edge portion 22A. When the globe 22 is fixed to the base plate 13, the projections 202 of the edge portion 22A of the globe 22 are fitted and held in the guide and hold grooves 201 of the side wall 19 of the base plate 13. More specifically, as shown in Fig. 16, the guide and hold groove 201 has an introducing (guide) groove 201A and a hold groove 201B. The introducing groove 201A is a groove into which the projection 202 of the globe 22 is introduced from the upper end 19A side, and it is provided by forming a vertical groove - 62 on the lower-stage peripheral surface 200A of the step portion 200. Furthermore, the hold groove 201B is a transverse groove which is continuous with the introducing groove 201A and extends in the peripheral direction Xs while moderately sloped downwards. When the projections 202 of the globe 22 are inserted into the introducing grooves 201A of the guide and hold grooves 201 to be introduced into the guide and hold grooves 201 and then the globe 22 is turned, the projections 202 are moderately guided downwards along the hold grooves 201B, and the globe 22 is pushed into the base plate 13 side. As shown in Fig. 17, a flange 203 is formed above the projection 202 at the edge portion 22A of the globe 22. When the projections 202 of the globe 22 are guided into the guide and hold grooves 201 and pushed into the base plate 13, the flange 203 abuts against the upper end 19A of the side wall 19, so that it is impossible to further push the globe 22 into the base plate 13 and the globe 22 is held in the base plate 13. As described above, the O-ring 26 as an example of the seal member for preventing water invasion into the fitting place between the globe 22 and the base plate 13 is provided between the globe 22 and the base plate 13. The O-ring 26 is not mounted on the step portion 200 of the base plate 13, but mounted on the outer peripheral surface (the confronting face to the side wall 19) of the edge portion 22A of the globe 22. Specifically, an O-ring fitting projection 204 is provided over the whole - 63 periphery of the edge portion 22A below the flange 203 of the globe 22. The flange 203 and the 0-ring fitting projection 204 of the globe 22 constitute an 0-ring fit-in groove 205, and the 0-ring 26 is fitted in the 0-ring fit-in groove 205. The O-ring 26 fit in the 0-ring fit-in groove 205 is pressed between the inner peripheral surface of the side wall 19 of the base plate 13 and the O-ring fit-in groove 205 when the globe 22 is secured to the base plate 13, thereby sealing the gap between the globe 22 and the base plate 13. Furthermore, in this embodiment, as not shown, caulking agent is injected into the gap between the O-ring 26 and the side wall 19 of the base plate 13 over the whole periphery thereof to construct a dual seal structure. Furthermore, by injecting the caulking agent, the introducing groove 201A of the guide and holding groove 201 is sealed, and the bore occurring in the step portion 200 in top view due to the introducing groove 201A is blocked by the introducing groove 201A. Accordingly, even when the globe 22 is loosened, the introducing groove 201A as the exit for the projection 202 is blocked, whereby the globe 22 can be prevented from dropping. In the seal structure described above, when the globe 22 is secured to the base plate 13 while rotated, the 0-ring 26 slides against the side wall 19 of the base plate 13 and thus it is rubbed by the side wall 19. Therefore, when the rotation amount is large, the 0-ring 26 is easily twisted and distorted - 64 by the rubbing from the side wall 19. Therefore, according to this embodiment, as shown in Fig. 16, the extension length Lh in the peripheral direction Xs of the hold groove 201B of the guide and hold groove 201 is set to be shorter than that of the whole periphery of the lower-stage peripheral surface 200A, preferably set to be shorter than at least the half peripheral length, and more preferably set so that the rotational angle of the globe 22 when the globe 22 is rotated while guided by the hold groove 201B is equal to 300. Accordingly, as compared with the structure that the globe 22 is fixed to the base plate 13 by screwing, the rotation (turning) amount of the globe 22 when the globe 22 is fixed is suppressed to the upper limit corresponding to the length Lh in the peripheral direction Xs of the hold groove 201B, so that the distortion of the 0-ring 26 can be reduced, and degradation of the waterproof performance can be prevented. Fig. 18 is a diagram showing a comparative example in which the globe 22 is screwed to the base plate 13. As the screwing structure of the globe 22 may be considered a structure that the step portion 200 is formed on the side wall 19 of the base plate 13, a screw groove 210 is formed on the lower-stage peripheral surface 200A of the step portion 200, and the edge portion 22A of the globe 22 is screwed to the screw groove 210 as shown in Fig. 18. As the seal structure using the 0-ring 26 may be considered a structure that the O-ring 26 is - 65 mounted on the upper end face 200B of the step portion 200 and pressed by the flange 203 of the glove 22 for sealing as shown in Fig. 18. However, the 0-ring 26 is sandwiched between the globe 22 and the step portion 200 of the base plate 13. Therefore, when the screwing of the globe 22 is loosened and thus it moves upwards even slightly with respect to the base plate 13, the press force of the globe 22 against the 0-ring 26 is weakened and the waterproof performance degrades. On the other hand, according to this embodiment, the 0-ring 26 is fitted in the gap between the 0-ring fit-in groove 205 of the edge portion 22A of the globe 22 and the side wall 19 of the base plate 13. Therefore, even when the globe 22 upwardly moves relatively to the base plate 13, no great variation occurs in the gap between the 0-ring fit-in groove 205 of the edge portion 22A of the globe 22 and the side wall 19 of the base plate 13, and thus the press force of the O-ring 26 is kept, so that the sealing performance is not weakened. The projections 202 of the globe 22 are inferior in mechanical strength to the screw threads in the screwing structure shown in Fig. 18. However, under the fixed state of the globe 22, the repulsive force of the 0-ring 26 acts on the gap between the O-ring fit-in groove 205 of the edge portion 22A of the globe 22 and the side wall 19 of the base plate 13, and it does not act so as to push up the flange 203 of the globe 22 from the - 66 step portion 200 of the side wall 19. Therefore, the repulsive force of the O-ring 26 does not serve as a load on the projection 202, and thus the projections can be prevented frombeing damaged. In the screwing structure of Fig. 18, the screw groove 210 is provided on the low-stage peripheral surface 200A. Therefore, the lower-stage peripheral surface 200A projects inwardly by the amount corresponding to the screw thread 210A of the screw groove 210, which cause increase of the thickness of the side wall 19. In addition, in order to keep the strength of each groove of the screw groove 210, it is necessary to enlarge the screw thread 210A in the height direction and thus increase the thickness between the grooves, resulting in increase of the height of the side wall 19. As described above, in the screwing structure, the side wall 19 is designed to be thick and high, so that the volume thereof is increased, the weight of the housing 35 is caused to increase and the weight difference from a conventional glass bulb lamp is increased. Furthermore, since the side wall 19 is designed to be high, the light shielding amount of light 212 emitted from LED 15 increases, and the light output ratio (luminaire efficiency) is lowered. On the other hand, according to this embodiment, it is unnecessary to provide the screw groove 210 to the side wall 19. Therefore, the thickness and height of the side wall 19 can be suppressed, and the weight of the housing 35 can be reduced.
- 67 In addition, the light shielding amount of light of LED 15 can be reduced, and the luminaire efficiency can be increased. Furthermore, according to this embodiment, as shown in Fig. 17, a reflection face 215 is provided to the inner peripheral surface of the edge portion 22A of the globe 22 to reflect light 212 incident from the LED 15 to the side wall 19, thereby further increasing the luminaire efficiency. Furthermore, the 0-ring 26 is used as the seal member for sealingthegapbetweentheglobe22andthebaseplatel 3 . However, a packing member having another shape or the like may be used as the seal member. The LED lamp 1 of this embodiment is used not only while mounted on the lamp holder 60 shown in Fig. 1, but also while mounted on an exposed socket 65. When the socket 65 is set up outdoors, in order to prevent invasion of water into the socket 65, the mount portion Bx between the socket 65 and the base 3 is covered by a substantially cylindrical waterproof packing 230 as shown in Fig. 19, thereby preventing water invasion from an opening 65A of the socket 65. Furthermore, the waterproof packing 230 has flexibility, and fastens the cylindrical portion 2 of the LED lamp 1 and the socket 65. Therefore, the waterproof packing 230 has a function of linking the LED lam 1 to the socket 65 and preventing the LED lamp 1 from dropping out of the socket 65. Particularly, the waterproof packing 230 of this embodiment has a socket mount - 68 barrel portion 238 as a chest portion to be mounted on the socket 65, and the socket mount barrel portion 238 reduces its diameter so as to firmly fasten the socket 65, whereby the waterproof packing 230 is firmly joined to the socket 65. However, the outer peripheral surface of the cylindrical portion 2 of the LED lamp 1 is configured in a tapered surface shape which is narrowed to the base 3. Accordingly, if no countermeasure is taken, the engagement between the LED lamp land the socket 65 starts loosening, and the close contact between the waterproof packing 230 and the cylindrical portion 2 of the LED lamp 1 degrades, so that the waterproof performance degrades. Furthermore, when the engagement between the LED lamp 1 and the socket 65 starts loosening, the fastening of the cylindrical portion 2 of the LED lamp 1 by the waterproof packing 230 is weakened, so that the anti-drop function of preventing the LED lamp 1 from dropping out of the socket 65 is weakened. Particularly, the LED lamp 1 has relatively high power, and it is suitably used for outdoor illumination of billboards and outdoor light-up illumination. Therefore, it is liable to suffer vibration of vehicles running on a road near to the LED lamp 1, and the vibration may cause the engagement between the LED lamp 1 and the socket 56 to start loosening. Furthermore, when the LED lamp 1 is located at a position higher than an illumination target such as a billboard or the like and illuminates the illumination target from the upper side - 69 of the illumination target while the base 3 is postured to be higher than the light emitting portion 12, force which makes LED lamp 1 drop out of the socket 65 is applied to the LED lamp ldue to the deadweight of the LED lamp 1 at all times. Therefore, once the engagement between the LED lamp 1 and the socket 65 starts loosening, it immediately causes the LED lamp 1 to drop out of the socket 65. Therefore, according to this embodiment, as shown in Fig. 19, a convex portion 232 as a fitting structure portion to which the upper edge portion 230A of the waterproof packing 230 is fitted is provided over the whole peripheryof the outer peripheral surface of the cylindrical portion 2 so as to be located at a higher position than the base 3. In addition, a concave portion 234 in which the convex portion 232 is fitted is provided over the whole periphery of the inner peripheral surface of the upper edge portion 230A of the waterproof packing 230. Accordingly, even when the engagement between the LED lamp 1 and the socket 65 is loosened, the upper edge portion 230A of the water proof packing 230 continues to be fitted to the convex portion 232 as the fitting structure portion, and thus the waterproof performance does not degrade. Furthermore, in order to allow the LED lamp 1 to drop out of the socket 65, the convex portion 232 of the cylindrical portion 2 is required to get over the concave portion 234 of the upper edge portion 230A ofthewaterproofpacking230. Therefore, theanti-dropfunction - 70 of the LED lamp 1 can be continued. In addition, the waterproof packing 230 and the cylindrical portion 2 are fitted to each other by the convex portion 232 of the cylindrical portion 2 and the concave portion 234 of the waterproof packing 230, whereby the sealing performance can be achieved by the engagement between the convex portion and the concave portion, and water invasion from the upper edge portion 230A of the waterproof packing 230 can be suppressed. Furthermore, plural convex portions 236 are provided over the whole periphery of the inner peripheral surface of the waterproof packing 230, and the convex portions 236 come into contact with the outer peripheral surface of the cylindrical portion 2 to enhance the sealing performance. Still furthermore, the frictional force between the waterproof packing 230 and the cylindrical portion 2 is enhanced, thereby further enhancing the anti-drop effect. The foregoingconstructionmaybemodifiedsothataconcave portion is provided as the fitting structure portion to the cylindrical portion 2 in place of the convex portion 232 and also a convex portion is provided to the upper edge portion 230A of the waterproof packing 230 in place of the concave portion 234. Furthermore, when the LED lamp 1 is used indoors, a packing having waterproof properties such as the waterproof packing 230 is not necessarily used. Any member may be used insofar as it is a cylindrical member which is mounted on the cylindrical portion - 21 2 of the LED lamp 1 to fasten the cylindrical portion 2 and has a structure for linking the cylindrical portion 2 to the socket 65. As described above, the following effects can be obtained by the foregoing embodiment. That is, according to the embodiment, the 0-ring 26 which is pressed between the globe 22 and the side wall 19 of the base plate 13 is provided over the whole periphery of the outer peripheral surface of the edge portion 22A of the globe 22, the projections 202 are provided below the 0-ring 26, and the guide and hold groove 201 for introducing (guiding) the projection 202 of the globe 22 from the upper end 19A side, guiding the projection 202 in the peripheral direction and holding the projection 202 is provided on the inner peripheral surface of the side wall 19 of the base plate 13. According to this construction, as compared with the construction of fixing the globe by screwing, the rotation amount (turning amount) of the globe 22 when the globe 22 is fixed can be reduced to the guide amount level of the projection 22 in the peripheral direction along the guide and hold groove 201. Therefore, the distortion of the seal member when the globe is fixed can be reduced, and the degradation of the waterproof performance can be prevented. Furthermore, according to this embodiment, the 0-ring 26 is fitted in the 0-ring fit-in groove 205 provided over the whole - 72 periphery of the outer peripheral surface of the edge portion 22A of the globe 22, and the O-ring 26 is pressed between the inner peripheral surface of the side wall 19 of the base plate 13 and the O-ring fit-in groove 205 to seal the gap between the base plate 13 and the globe 22. According to this construction, even when the globe 22 moves upwards with respect to the base plate 13, no great variation occurs in the gap between the 0-ring fit-in groove 205 of the edge portion 22A of the globe 22 and the side wall 19 of the base plate 13, and the press force of the O-ring 26 is kept, so that the sealing performance is not weakened. Furthermore, the repulsive force of the O-ring 26 acts between the 0-ring fit-in groove 205 of the edge portion 22A of the globe 22 and the side wall 19 of the base plate 13, and thus there is not any force which acts on the flange 203 of the globe 22 so as to push up the flange 203 of the globe 22 from thestepportion200ofthesidewall19. Therefore, therepulsive force of the O-ring 26 is prevented from being applied to the projections 202 as a load, and thus the projections 202 can be prevented from being damaged. Still furthermore, according to this embodiment, the reflection face 215 for reflecting the light 212 incident from LED 15 to the side wall 19 is provided to the inner peripheral surface of the edge portion 22A of the globe 22. Therefore, the light shielded by the side wall 19 can be used for illumination, - 23 and the luminaire efficiency can be increased. Still furthermore, the plural heat radiation fins 25 extending along the cylindrical portion 2 are arranged radially around the cylindrical portion 2 on the back surface 13A of the base plate 13 on which the LED board 16 having LEDs 15 mounted thereon is mounted so that the gap S is provide between each heat radiation fin 25 and the cylindrical portion 2. There are provided the joint portions 105 through which the end portions at the cylindrical portion 2 side of the respective two adjacent heat radiation fins 25 are joined to each other, thereby forming the air flow path F between the cylindrical portion 2 and each joint portion 2. Accordingly, the outer peripheral surface of the cylindrical portion 2 can be air-cooled by air passing through the air flow paths F, and the electrical circuit board 8 accommodated in the cylindrical portion can be cooled. Particularly, the thermal conductive member 29D is provided between the heating part 8X of the electrical circuit board 8 and the cylindrical portion 2 to transfer the heat of the heating part 8X to the cylindrical portion 2. Therefore, the heat of the heating part 8X of the electrical circuit board 8 can be efficiently cooled, and the circuit can be stably operated. Furthermore, according to this embodiment, the distributing fin 103 for distributing air stream to each of the adjacent open trapezoidal fins 101 is provided between the adjacent open trapezoidal fins 101.
- 74 According to this construction, the air stream passing through the gap between the adjacent open trapezoidal fins can be distributed to each of the adjacent open trapezoidal fins 101 by the distributing fin 103 located between the adjacent open trapezoidal fins 101. Accordingly, unevenness of cooling hardly occurs on the outer peripheral surface of the cylindrical portion 2, and thus the cylindrical portion 2 can be uniformly cooled. According to this embodiment, the short heat radiation fin 102 which is shorter than the heat radiation fin 25 in the extension length from the back surface 13A of the base plate 13 (in the longitudinal (vertical) direction of the LED lamp 1) is provided between the heat radiation fins 25 constituting each open trapezoidal fin 101. According to this construction, the heat radiation performance of the base plate 13 is assisted, and LED 15 having higher power can be mounted. In addition, the short heat radiation fin 102 can be configured to be shorter than the heat radiation fin 25, so that air flow in each open trapezoidal fin 101 is not disturbed, and the cooling performance of the open trapezoidal fins 101 which mainly radiate heat is not disturbed. Furthermore, according to this embodiment, the outside annular fins 106 and the inside annular fins 107 as the plural annular heat radiation fins which are shorter than the short heat radiation fins 102 in the extension length from the back - 75 surface 13A (in the longitudinal (vertical) direction of the LED lamp 1) and surround the cylindrical portion 2 are provided on the back surface 13A of the base plate 13. According to this construction, randomness occurs in the air flow in each open trapezoidal fin 101 and between adjacent open trapezoidal fins 101 by the outside annular fins 106 and the inside annular fins 107, and the retaining period of air is lengthened, so that the cooling performance can be enhanced. According to this embodiment, the base plate 13 to which LEDs 15 are secured and the plural heat radiation fins 25 formed on the back surface 13A of the base plate 13 are molded integrally with each other by using resin, and the base plate 13 and the heat radiation fins 25 are configured so as to be gradually thinner from the inner periphery to the outer periphery thereof. Accordingly, the heat radiation fins 25 are thicker on the thicker base plate 13 at the inner peripheral side thereof, and thinner on the thinner base plate at the outer peripheral side thereof. Therefore, occurrence of sink (shrinkage) of resin at the fin root portions 25B of the heat radiation fins 25 on the back surface 13A of the base plate 13 can be prevented, and the flatness of the base plate 13 can be enhanced, thereby radiating heat efficiently. Furthermore, the strength of the heat radiation fins 25 can be secured by the thick base plate 13 and the thick heat radiation fins 25 at the inner peripheral side of the base plate - 76 13, and the heat radiation performance can be enhanced by the thin base plate 13 and the thin heat radiation fins 25 at the outer peripheral side. Still furthermore, according to this embodiment, a larger number of LEDs 15 are provided to the outer-peripheral side light emitting portion 15A at the outer peripheral side of the base plate 13 than the inner-peripheral side light emitting portion 15B at the inner peripheral side of the base plate 13. Although the amount of generated heat at the outer peripheral side is larger, thebaseplate 13 at theouterperipheral side is configured tobe thinner, and thustheheat resistanceattheouterperipheral side of the base plate 13 is smaller, so that the heat can be efficiently radiated. Still furthermore, according to this embodiment, the length in the axial (height) direction of the heat radiation fins 25 is gradually shorter from the inner periphery of the base plate 13 to the outer periphery of the base plate 13. Therefore, the bending moment acting on the heat radiation fins 25 is larger at the inner peripheral side of the base plate 13 and smaller at the outer peripheral side of the base plate 13. However, the base plate 13 and the heat radiation fins 25 are configured to be gradually thinner from the inner periphery to the outer periphery, and the base plate 13 and the heat radiation fins 25 can be made thinner. Therefore, both the strength and the heat radiation performance of the heat radiation fins 25 can - 77 be performed. Still furthermore, according to this embodiment, the thickness of the heat radiation fins 25 is gradually reduced from the back surface 13A of the base plate 13 to the base 3 side. Therefore, the slope surface of the heat radiation fin 25 functions as a release taper at a demolding step, so that the resin molding of the base plate 13 and the heat radiation fins 25 can be easily performed. According to this embodiment, the base 3 to which the lead wires 21A and 21B extending from LED 15 are connected is provided to the tip of the insulating cylinder portion 10, the tip of the insulating cylinder portion 10 is configured as the bag portion 120, the terminal 10A having the screw portion 33 which is engaged with the base 3 is provided on the outer periphery of the tip, the bag portion 120 of the tip is projected to the upper and outer side of the end face 123A of the terminal 10A, and the wire holes 125A and 125B as the through-holes through which the lead wires 21A and 21B penetrate are provided to the projecting portions 122A and 122B of the bag portion 120. Therefore, even when water such as dew condensation or the like adheres to the neighborhood of the terminal 1OA, the water hardly intrudes into the wire holes 125A and 125B of the projecting portions 122A and122Bprojectingtotheoutsideoftheendfacel23A. Therefore, water can be prevented from invading from the wire holes 125A and 125B into the housing 35 of the LED lamp 1.
- 78 According to this embodiment, the pair of introducing portions 127A and 127B for leading the pair of lead wires 21A and 21B into the wire holes 125A and 125B are formed on the inner surface of the bag portion 120, and the introducing portions 127A and 127B are separated from each other by the partition wall 126 for bisecting the inner surface of the bag portion 120. Therefore, the wire leads can be surely guided to the wire holes 125A and 125B corresponding to the introducing portions 127A and 127B by the pair of introducing portions 127A and 127B formed by bisecting the inner surface of the bag portion 120 through the partition wall 126, and the assembling performance of the lead wires 21A and 21B can be enhanced. Still furthermore, according to this embodiment, the introducing portions 127A and 127B are conical concaves which are tapered to the wire holes 125A and 125B, and the lead wires 21A and 21B can be easily passed through the wire holes 125A and 125B along the conical shapes. Furthermore, the wire groove 34 in which the lead wire 21B passed through the wire hole 125B and drawn out to the outside is fitted is formed on the outer peripheral surface of the terminal 10A, and the bag portion 120 projects to the upper and outer side of the wire groove 34. Therefore, water in the neighborhood of the wire groove 34 can be suppressed from invading from the wire holes 125A, 125B of the bag portion 120 into the housing 35 of the LED lamp 1.
- 79 Furthermore, according to the above embodiment, the plural heat radiation fins 25 formed on the base plate 13 are provided, the pin 130 is bridged between the two heat radiation fins 25, andthe anti-dropwire 131 is connectedto the pin 130. Therefore, the anti-drop wire 131 can be connected with the simple structure that the pin 130 is bridged between the heat radiation fins 25, and the pin 130 is provided between the two heat radiation fins 25, so that the pin 130 can be firmlyprovided totheheat radiation fins 25, and the LED lamp 1 can be surely prevented from dropping out. Furthermore, it is unnecessary to provide a dedicatedmember for fixing the pin 130. Furthermore, according to this embodiment, the heat radiation fins 25 between which the pin 130 is bridged are arranged substantially in parallel to each other, the pin 130 is supported through the support holes 134 formed in the substantially parallel heat radiation fins 25, and the support holes 134 can be easily formed in the substantially parallel heat radiation fins 25. Therefore, the pin 130 can be simply provided to the heat radiation fins 25. Still furthermore, according to this embodiment, the anti-drop wire 131 is joined to the band 133 wound around the outer peripheral surface of the lamp holder 60 for supporting the LED lamp 1. Therefore, the LED lamp 1 can be prevented from dropping with a simple construction that the band 133 is wound around the outer peripheral surface of the lamp holder 60 and - 80 the anti-drop wire 131 is connected to the band 133. Since the band 133 is wound around the lamp holder 60, the band 133 is adaptable to lamp holders having various shapes. The LED lamp 1 is screwed to the socket 65 of the lamp holder60byrotatingtheLEDlampl. Theband133hastheadjusting portion 136 which can adjust the constriction force of the band 133, and the band 133 is rotatable on the outer peripheral surface of the lamp holder 60 by loosening the constriction force of the band 133. Therefore, the anti-drop wire 131 can be connected to the band 133, and the band 133 is slightly loosened so as to be rotatable around the outer peripheral surface of the lamp holder 60. Under this state, the work of attaching/detaching the LED lamp 1 can be performed by rotating the Led lamp 1, so that the LED lamp 1 can be prevented from dropping during the attaching/detaching work. According to this embodiment, the convex portion 232 as the fitting structure portion which is configured to be fitted to the waterproof packing 230 as the cylindrical member having the function of linking the cylindrical portion 2 to the socket 65 is provided on the outer peripheral surface of the cylindrical portion 2. Accordingly, even when the engagement between the LED lamp 1 and the socket 65 is loosened, the upper edge portion 230A of the waterproof packing 230 continues to be fitted to the convex portion 232 as the waterproof packing fitting portion. Therefore, - 81 the waterproof performance does not degrade, and the anti-drop effect of the LED lamp 1 is prevented from being lost by the fitting between the upper edge portion 230A of the waterproof packing 230 and the convex portion 232 as the waterproof packing fitting portion. Furthermore, according to this embodiment, the waterproof packing fitting portion is constructed by the convex portion 232 to be fitted to the upper edge portion 230A of the waterproof packing 230 over the whole periphery of the cylindrical portion 2. Therefore, the sealing performance is obtained by the engagement between the convex portion 232 of the cylindrical portion 2 and the waterproof packing 230, and water invasion from the upper edge portion 230A of the waterproof packing 230 can be suppressed. Still furthermore, accordingtothisembodiment, theconvex portion 236 is provided over the whole periphery of the inner peripheral surface of the waterproof packing 230. Therefore, the waterproof performance can be enhanced. According to this embodiment, the support holes 134 as the connection portions to which the anti-drop wire 131 is connected are provided between the light emitting portion 12 and the base 23 so as to be nearer to the base 3 than the center-of-gravity position Gx of the dead weight of the LED lamp 1. According to this construction, even when the LED lamp - 82 1 drops out of the socket 65 under the state that the LED lamp 1 is mounted on the socket 65 while the base 3 is disposed to be vertically higher than the light emitting portion to illuminate the lower side, the center-of-gravity position Gx of the dead weight has been already vertically lower than the support holes 134, so that the amount of turning of the LED lamp 1 caused by the drop-out can be reduced and the swing width of the LED lamp 1 caused by the turning can be reduced. Accordingly, impingement of the LED lamp 1 against an illumination target such as a billboard or the like existing in the neighborhood of the LED lamp 1 can be avoided, and even when the LED lamp 1 impinges against the illumination target, the impact caused by the impingement can be suppressed. Furthermore, in this embodiment, the support holes 134 are provided to the heat radiation fins 25. Therefore, when the LED lamp 1 is used while mounted on the lamp holder 60, the support holes 134 do not intrude in the lamp holder 60, and the anti-drop wire 131 can be simply connected to the support holes 134. The foregoing embodiment is an example of the present invention, and any modification and application may be made to the above embodiment without departing from the subject matter of the present invention.

Claims (26)

1. A lamp including a board having light emitting elements mounted thereon, a flat plate portion having the board mounted thereon, and a cylindrical portion that extends from the back surface of the flat plate portion, has a base provided to the terminal thereof and contains an electrical circuit board therein, comprising: a plurality of heat radiation fins that are arranged radially around the cylindrical portion on the back surface of the flat plate portion and configured to extend along the cylindrical portion so that a gap is formed between the cylindrical portion and each of the heat radiation fins; and a joint portion for joining end portions at a cylindrical portion side of at least two paired heat radiation fins to form an air flow path between the cylindrical portion and the joint portion facing the cylindrical portion, wherein air is introduced from outside through a space between adjacent pairs of heat radiation fins to the air flow path and discharged through a space between other adjacent pairs of heat radiation fins to the outside.
2. The lamp according to claim 1, further comprising a distributing fin that is disposed between adjacent pairs of heat radiation fins to distribute an air stream to each of the adjacent pairs of heat radiation fins.
3. The lamp according to claim 1 or 2, further comprising a short heat radiation fin that is provided between the respective paired 9006158_1 84 heat radiation fins joined through the joint portion and configured to be shorter than the heat radiation fins in the extension length from the back surface of the flat plate portion.
4. The lamp according to any one of claims 1 to 3, further comprising a plurality of annular heat radiation fins that are arranged on the back surface of the flat plate portion so as to surround the cylindrical portion and configured to be shorter than the short heat radiation fins in the extension length from the back surface of the flat plate portion.
5. The lamp according to any one of claims 1 to 4, further comprising a thermally conductive member that is provided between a heating part of the electrical circuit board and the cylindrical portion to transfer heat of the heating part to the cylindrical portion.
6. The lamp according to claim 1, wherein each of the heat radiation fins is molded on the back surface of the flat plate portion integrally with the flat plate portion, and configured to be gradually thinner from the cylindrical portion side to the outer peripheral side.
7. The lamp according to claim 6, wherein a larger number of light emitting elements are provided at the outer side of the board that that at the center side of the board.
8. The lamp according to claim 6 or 7, wherein the heat radiation 9006158_1 85 fins are configured so that the extension length thereof along the cylindrical portion is gradually reduced from the cylindrical portion side to the outer peripheral side.
9. The lamp according to any one of claims 6 to 8, wherein the thickness of the heat radiation fins is gradually reduced from the back surface side of the flat plate portion to the base side.
10. The lamp according to claim 1, further comprising a globe covering the board of the flat plate portion, wherein the flat plate portion is configured in a tray-like shape having a side wall at the edge thereof, an edge portion of the globe is fitted to the side wall, the fitting portion between the edge portion of the globe and the side wall is sealed by a seal member, the seal member is provided over the whole periphery of the outer surface of the edge portion of the globe so as to be pressed between the side wall of the flat plateportionandthe edgeportionof the globe, aprojection is provided below the seal member, and a guide and hold groove for introducing the projection of the globe from an upper end side and guiding the projection in a peripheral direction to hold the globe.
11. The lamp according to claim 10, wherein a fit-in groove is provided over the whole periphery of the outer surface of the edge portion of the globe, and the seal member is fitted in the fit-in groove so that the seal member is pressed between the inner surface of the side wall of the flat plate portion and the fit-in groove to 9006158_1 86 seal the fitting portion between the sidewall of the flat plate portion and the edge portion of the globe.
12. The lamp according to claim 11, further comprising a reflection face for reflecting light of the light emitting elements is provided on the inner surface of the edge portion of the globe.
13. The lamp according to claim 1, wherein the cylindrical portion is configured to be thinner from the flat plate portion side to the base side, a cylindrical member for linking the cylindrical portion toasockettowhichthebaseis screwedismountedontheouterperipheral surface of the cylindrical portion, and a fitting structure portion to be fitted to the cylindrical member when the cylindrical member ismountedisprovidedtotheouterperipheralsurfaceofthecylindrical portion.
14. The lamp according to claim 13, wherein the cylindrical member is a waterproof packing that covers an area extending from the socket having the base mounted thereon to the cylindrical portion to prevent water invasion between the base and the socket.
15. The lamp according to claim 14, wherein the fitting structure portion is provided with a convex portion or a concave portion to which an upper edge portion of the waterproof packing is fitted over the whole periphery of the cylindrical portion. 9006158_1 87
16. The lamp according to claim 14 or 15, wherein a convex portion is provided over the whole periphery of the inner peripheral surface of the cylindrical member.
17. The lamp according to claim 1, wherein a connection member is bridged between at least two heat radiation fins, and an anti-drop support member is connected to the connection member.
18. The lamp according to claim 17, wherein the heat radiation fins bridged by the connection member are provided substantially in parallel to each other, a hole portion is formed in each of the substantially parallel heat radiation fins so as to penetrate through the heat radiation fin, the connection member is configured in a rod-like shape, and the rod-like connection member is supported through the hole portions of the substantially parallel heat radiation fins.
19. The lamp according to claim 17 or 18, wherein the connection member is joined to a band wound around the outer peripheral surface of a lamp holder for supporting the lamp.
20. The lamp according to claim 19, wherein the lamp is rotated to be screwed to the lamp holder, and the band has an adjusting portion for adjusting constriction force of the band, and is allowed to be rotatableontheouterperipheralsurfaceofthelampholderbyloosening the constriction force of the band. 9006158_1 88
21. The lamp according to any one of claims 17 to 20, wherein the connection member is provided between the flat plate portion and the base so as to be nearer to the base than the center-of-gravity position of the dead weight of the lamp.
22. The lamp according to claim 21, wherein the connection member is provided to be nearer to the base than the heat radiation fins of the cylindrical portion.
23. The lamp according to claim 1, further comprising a lead wire unit that is connected through the cylindrical portion to the base to supply power to the plurality of light emitting elements, a bag portion formed at the tip of the cylindrical portion, and an engaging portion that is formed on the outer periphery of the tip so as to be engaged with the base, wherein the bag portion of the tip isprojectedto the outside of the fittingportion, andtheprojected bag portion is provided a through-hole unit through which the lead wire unit penetrates.
24. The lamp according to claim 23, wherein the through-hole unit has a pair of through-holes, the lead wire unit has a pair of through holes, a pair of introducing portions for guiding the pair of lead wires to the pair of through-holes are formed on the inner surface of the bag portion, and the introducing portions are separated from each other by a partition wall for bisecting the inner surface. 9006158_1 89
25. The lamp according to claim 24, wherein the pair of introducing portions are configured as conical concaves that are tapered to the through-holes.
26. The lamp according to claim 24 or 25, wherein a groove portion in which one of the lead wires drawn through one of the through-holes to the outside is fitted is formed on the outer peripheral surface of the fitting portion, and the bag portion is configured to project to the outside of the groove portion. Iwasaki Electric Co., Ltd Patent Attorneys for the Applicant SPRUSON & FERGUSON 9006158 1
AU2012233021A 2011-10-07 2012-10-02 Lamp Active AU2012233021B2 (en)

Applications Claiming Priority (14)

Application Number Priority Date Filing Date Title
JP2011223345A JP5772473B2 (en) 2011-10-07 2011-10-07 lamp
JP2011223364A JP5834744B2 (en) 2011-10-07 2011-10-07 lamp
JP2011223361A JP5772474B2 (en) 2011-10-07 2011-10-07 lamp
JP2011223360A JP5790389B2 (en) 2011-10-07 2011-10-07 lamp
JP2011223343A JP5862179B2 (en) 2011-10-07 2011-10-07 lamp
JP2011-223343 2011-10-07
JP2011-223342 2011-10-07
JP2011-223345 2011-10-07
JP2011-223344 2011-10-07
JP2011223342A JP5737120B2 (en) 2011-10-07 2011-10-07 lamp
JP2011223344A JP2013084435A (en) 2011-10-07 2011-10-07 Lamp
JP2011-223361 2011-10-07
JP2011-223364 2011-10-07
JP2011-223360 2011-10-07

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AU2012233021A1 AU2012233021A1 (en) 2013-05-02
AU2012233021B2 true AU2012233021B2 (en) 2014-09-11

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7458706B1 (en) * 2007-11-28 2008-12-02 Fu Zhun Precision Industry (Shen Zhen) Co., Ltd. LED lamp with a heat sink
US20090103308A1 (en) * 2007-10-19 2009-04-23 Fu Zhun Precision Industry (Shen Zhen) Co., Ltd. Led lamp with a heat sink

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090103308A1 (en) * 2007-10-19 2009-04-23 Fu Zhun Precision Industry (Shen Zhen) Co., Ltd. Led lamp with a heat sink
US7458706B1 (en) * 2007-11-28 2008-12-02 Fu Zhun Precision Industry (Shen Zhen) Co., Ltd. LED lamp with a heat sink

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