JP2015002076A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED lighting device capable of achieving both high output and long life.SOLUTION: A lighting device includes: an LED light emitting module having an LED; and a housing which houses the LED light emitting module. The housing includes a heat sink which radiates heat generated by the LED in at least a part thereof and further includes a driver housing having a substrate housing part for housing a power supply circuit board that controls electric power supplied to the LED. At least a part of the inner side of the substrate housing part is made of a metal and has a rib structure.

Description

  The present invention relates to a lighting device using LEDs as light emitting elements.

Light emitting diodes (hereinafter referred to as “LEDs”) are expected to be a new light source because they are smaller, more efficient, and have a longer life than conventional illumination light sources such as fluorescent lamps and incandescent lamps. In response to growing market needs for resource saving, various lighting devices using LEDs have been developed.
For example, Patent Document 1 describes a light bulb-shaped illumination device that can simulate the light emission shape of a filament during light emission in an existing incandescent light bulb by using an LED module. Specifically, in Patent Document 1, an LED chip having a plurality of nitride semiconductor layers having different compositions laminated on a sapphire substrate and a sapphire substrate is covered with a sealing material containing fluorescent material particles, etc. to dissipate heat. The LED module is mounted on one side surface of a base made of a highly functional member, and the LED module is fixed by a stem made of a material having a thermal conductivity larger than the thermal conductivity of the base. Thus, it is described that a decrease in luminous efficiency and lifetime of the LED chip due to a temperature rise can be suppressed (paragraphs [0116] [0117] [0125] to [0127] [0133] [0302] [ 0303]). It is described that the heat generated by the light emission of the LED chip can be released to the base through the stem, and the lighting circuit is accommodated in the base (paragraphs [0156] [0221]). .

  Further, in Patent Document 2, a light bulb-shaped lighting device using an LED includes a lighting circuit, and the lighting circuit includes a power supply circuit that performs AC-DC conversion, a lighting control circuit that controls a lighting state of the LED, and the like. In addition, it is described that various electronic components such as capacitors, resistors, and FETs are mounted on the circuit board (paragraphs [0025] and [0037]).

  Patent Document 3 describes a light bulb-like lighting device using an LED provided with a power supply circuit unit having a capacitor, and an electrolytic capacitor is indispensable for extending the life of the lighting device. In addition, it is necessary to increase the life of the electrolytic capacitor, and since the electrolytic capacitor uses an electrolytic solution, the heat resistance is particularly low, and the life of the electrolytic capacitor is correlated with the operating temperature, generally 10 ° C. It is described that when the operating temperature is lowered, the lifetime of the capacitor is doubled, and the lifetime of the electrolytic capacitor is easily influenced by the ambient temperature (paragraphs [0044] [0046] [0047]).

JP 2012-238602 A JP 2009-230971 A JP 2012-146574 A

Generally, when an LED is repeatedly emitted many times, or when high power is applied to obtain a high output and an excessive temperature rise of the LED chip is caused, the LED deteriorates and the light emission efficiency decreases. For this reason, there is known an illumination device using LEDs that includes a heat sink that efficiently dissipates heat generated by the LEDs. And in the case of patent document 1, the stem to which the LED module is fixed plays the role of a heat sink, and the thermal deterioration of the LED chip due to the temperature rise is suppressed.

  However, in the case of Patent Document 1, the heat generated with the light emission of the LED immediately reaches the lower power circuit board through the stem functioning as a heat sink, causing the temperature of the power circuit to rise, so that the circuit is destroyed. As a result, another problem of shortening the lifetime of the LED lighting device may occur. In such a case, if an unspecified electronic component among the plurality of components constituting the power supply circuit fails in an unpredictable state, the electronic component becomes a heat source and further increases the temperature around the circuit. It may fall into a vicious circle that shortens the life of LED lighting devices. In particular, when an electrolytic capacitor is used for an electronic component that constitutes an electric circuit of an LED lighting device, the electrolytic capacitor uses an electrolytic solution, so the heat resistance is particularly low, and the electrolytic capacitor is destroyed due to a rise in circuit temperature. The electrolytic solution vaporized from the electrolytic capacitor may be discharged into the electric circuit and the circuit component may be thermally damaged, or the resin portion may be thermally dissolved by overheating (see Patent Document 2 [0004] and Patent Document 3 [0047]). ).

  The present invention has been made in view of the above-mentioned problems, and the electrical circuit itself rises in temperature and thermally deteriorates due to heat transfer caused by light emission of the LED and heat generation of the power supply circuit and the like. An object of the present invention is to provide an LED lighting device that can be suppressed and can achieve both high output and long life.

The gist of the present invention for solving the above problems is as follows.
[1] An LED light emitting module having an LED, and a housing that houses the LED light emitting module, the housing including at least a part of a heat sink that dissipates heat generated by the LED, and the LED A driver housing having a substrate housing portion for housing a power supply circuit board for controlling the supplied power, wherein at least a part of the inside of the substrate housing portion has a thermal conductivity of 20 W / mK or more, and A lighting device having a rib structure in at least a part of the inside of the substrate housing portion.
[2] The illumination device according to [1], wherein the substrate housing portion is filled with a potting agent.
[3] The lighting device according to [1] or [2], wherein the board housing portion is not in direct contact with the power circuit board and the power circuit.
[4] The illumination device according to any one of [1] to [3], wherein an electrolytic capacitor is mounted on the power circuit board.
[5] The lighting device according to any one of [1] to [4], wherein a heat radiation paint is coated on the outside of the driver housing.
[6] The lighting device according to any one of [1] to [5], wherein the potting agent has a thermal conductivity of 0.8 W / mK or more.
[7] The illumination device according to any one of [1] to [6], wherein in the rib structure, the width of the convex portion is within a range of ± 30% of the width of the concave portion.
[8] The illumination device according to any one of [1] to [7], wherein the LED is an LED chip having at least a substrate and a nitride semiconductor layer on the substrate.

According to the present invention, in a lighting device including a driver housing having a board housing portion for housing a power circuit board that controls power supplied to the LED, a heat sink that dissipates heat generated by the LED is at least partially included. And comprising at least a part of the inside of the substrate housing part with a material having a predetermined thermal conductivity, and adopting a shape having a rib structure on at least a part of the inside of the board housing part, It is possible to suppress the heat deterioration due to the heat transfer caused by the light emission of the LED and the heat generation of the power supply circuit, etc., and to achieve both high output and long life. LED lighting device can be provided.

It is a disassembled perspective view of the illuminating device which concerns on embodiment. It is a perspective view of the illuminating device which concerns on embodiment. It is a perspective sectional view of the illuminating device concerning an embodiment. It is a perspective view of the illuminating device which concerns on embodiment. It is a perspective view of a driver housing concerning an embodiment. It is a perspective view of a driver housing concerning an embodiment. It is a perspective view of the conducting wire pressing member concerning an embodiment. It is a perspective view of the heat sink concerning an embodiment. It is a perspective view of the heat sink concerning an embodiment. It is a perspective view of the lens which concerns on embodiment. It is a perspective view of the lens holder which concerns on embodiment. It is sectional drawing of the illuminating device used by simulation. It is a front view of a driver housing (with a rib structure) used in simulation. It is a perspective view of a driver housing (with a rib structure) used in simulation. It is a front view of a driver housing (without a rib structure) used in simulation. It is a perspective view of a driver housing (without a rib structure) used in simulation.

  DETAILED DESCRIPTION Exemplary embodiments for carrying out the present invention will be described in detail below with reference to the drawings. It should be noted that the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are intended to limit the technical scope of the invention only to those unless otherwise specified. is not.

<Embodiment>
FIG. 1 is an exploded perspective view of a lighting device 1 according to the embodiment. FIG. 2 is a perspective view of the lighting device 1 according to the embodiment. FIG. 3 is a perspective cross-sectional view of the lighting device 1 according to the embodiment. FIG. 4 is a perspective view of the lighting device 1 according to the embodiment. The lighting device 1 is a lamp provided with a light emitting diode (hereinafter referred to as “LED”) 40 as a light source. The lighting device 1 includes a lens 2, a lens holder 3, an LED light emitting module 4, a heat sink 5, a driver housing 6, a conductor holding member 7, a circuit board 8, and the like.

  In the present specification, the side on which the lens 2 is provided is defined as “front” of the lighting device 1, and the side on which the conductor holding member 7 is provided is defined as “rear”. Further, in the present embodiment, a case where the lighting device 1 is an MR16 type LED lighting device that can be replaced with an MR16 type halogen bulb having an outer diameter of, for example, about 50 mm will be described as an example. FIG. 4 shows a perspective view when the illumination device 1 is viewed from the front.

As will be described later, the LED light-emitting module 4 includes an LED 40, and it is preferable to use an LED chip having at least a substrate and a nitride semiconductor layer on the substrate.
The housing 10 is for housing the LED light emitting module 4. The housing 10 includes a heat sink 5 that dissipates heat generated by the LEDs 40, and a board housing portion 61 for housing a power circuit board 8 (see FIG. 2) that controls the power supplied to the LEDs 40. And a housing 6.

The present invention is characterized in that at least a part of the inside of the substrate housing part 61 is made of a material having a high thermal conductivity, and a rib structure 700 is provided on at least a part of the inside of the board housing part 61 ( (See FIG. 5).
The thermal conductivity of such a material is 20 W / mK or more, preferably 50 W / mK or more, and more preferably 80 W / mK or more. As long as these thermal conductivity conditions are satisfied, the type of material having high thermal conductivity is not particularly limited, but metals such as aluminum and copper are preferable, and aluminum is particularly preferable. Moreover, as long as the above conditions are satisfied, ceramics such as alumina may be used.
The material having a high thermal conductivity is 30% or more, preferably 50% or more, more preferably 70% or more, still more preferably 90% or more, and most preferably 100% of the total area inside the substrate housing 61. It is preferable to occupy the area.
In the present invention, the rib structure refers to a structure having a plurality of plate-like protrusions having a shape such as a flat plate or a curved plate. Hereinafter, the protrusions are convex, and the gap between the protrusions and the protrusions. This is called a recess. The rib structure may be provided over the entire inner surface of the substrate housing portion. However, in order to efficiently use the inner space, the rib structure may be provided over only the inner half or less of the surface.

  The rib structure 700 is not particularly limited as long as the substrate housing 61 can accommodate a predetermined substrate, but has a structure that can efficiently dissipate heat accumulated in the substrate housing 61 to the outside. Preferably, there is a greater surface area associated with the rib structure 700. Further, in the rib structure 700, when the width of the convex portion is within a range of ± 30%, preferably ± 25%, more preferably ± 20% of the width of the concave portion, heat accumulated in the substrate housing portion 61 is stored. Can be efficiently removed to the outside. By forming the rib structure with the material having the high thermal conductivity, the effects of both can be combined to further enhance the heat dissipation effect.

The power supply circuit board 8 and the power supply circuit are preferably used in a form that is not in direct contact with the board housing portion. By avoiding direct contact in this way, it is possible to avoid the danger of the power supply circuit being shorted and destroyed.
Further, by adopting the aspect as a double-sided board using both sides of the circuit board by placing the circuit board 8 for power supply in a vertical position in the board housing portion 61 and further adopting the above rib structure 700. This is preferable because a more compact structural design is possible.

  Further, when an electrolytic capacitor is mounted on the circuit board 8 for power supply, as described above, the lighting device is easily turned on when the electrolytic capacitor reaches a temperature close to 100 ° C., and the thermal deterioration is caused by the entire lighting device. In such a case, the application of the present invention capable of extremely efficiently suppressing the temperature rise of the substrate housing portion 61 due to heat dissipation achieves both high output and long life of the lighting device. This is particularly significant in that it can be achieved.

  Further, in order to reduce the thermal load on the circuit board 8 and the electrical components on the board and to enhance the stability, it is preferable that the board housing portion 61 for housing them is filled with a potting agent. As the potting agent, those having high thermal conductivity are preferably used, those having a thermal conductivity of greater than 0.8 W / mK are preferred, those having a thermal conductivity of 1.4 W / mK or more are more preferred, and those having a thermal conductivity of 2.0 W / mK or more are further preferred. preferable. The potting agent is preferably a resin-based material that does not have electrical conductivity. Specifically, a heat conductive silicone resin having heat resistance (for example, RTV silicone rubber for electric / electronic use made by Shin-Etsu Silicone) can be appropriately selected and used suitably. The potting agent may contain a filler (for example, non-conductive filler, silicon dioxide, etc.). By using such a composite material, desired high thermal conductivity and insulation are realized. May be.

Next, details of the driver housing 6 and the like will be described. 5 and 6 are perspective views of the driver housing 6 according to the embodiment. In FIG. 7, the perspective view of the conducting wire pressing member 7 which concerns on embodiment is shown.
For the driver housing 6, various resins, inorganic materials such as ceramics, and metals such as aluminum may be applied, or a combination thereof may be used. In addition, from the viewpoint of heat dissipation, a commercially available heat dissipating paint (for example, transparent heat dissipating paint “Unicool” manufactured by Godo Ink Co., Ltd., heat dissipating coating agent “Cooltech” manufactured by Okitsumo Co., Ltd. 200) etc.) is preferably used. By adopting such a configuration, the heat dissipation effect from the inside of the driver housing 6 can be further enhanced. In the present embodiment, aluminum alloy (ADM12) is used as the material of the driver housing 6, but the material is not limited to this, and the material exemplified in the substrate housing portion 61 or PBT (polybutylene terephthalate having no conductive performance) is used. ) Or the like may be used. The driver housing 6 includes a board housing portion 61 that houses the circuit board 8 (see FIG. 2), and a conductor presser mounting portion 62 that is connected to the rear of the board housing portion 61. The substrate housing portion 61 includes a bottom portion 611 and a cylindrical wall portion 612 erected on the bottom portion 611. The cylindrical wall portion 612 is a connecting portion that is fitted to the heat sink 5 and connects the driver housing 6 to the heat sink 5 via a fastener such as a screw.

  Further, the driver housing 6 includes a set of fixing portions 613 in which screw grooves for attaching fixing screws 42 described later are formed. As shown in FIG. 5, the fixing portion 613 is disposed along the inner surface of the cylindrical wall portion 612. In the present embodiment, in the circumferential direction of the cylindrical wall portion 612, the fixed portions 613 are arranged at positions facing each other. However, the number of the fixed portions 613 installed, the arrangement position, and the like may be changed as appropriate. Further, a pair of U-shaped notches 614 are formed at the front end edge of the cylindrical wall portion 612 in the driver housing 6 (substrate housing portion 61). The pair of notches 614 are also arranged at positions that are just facing each other in the circumferential direction of the cylindrical wall portion 612.

  As shown in FIG. 6, the conductor presser mounting portion 62 in the driver housing 6 has a substantially rectangular tube shape, and one end of the mounting portion 62 is connected to the bottom portion 611 of the substrate housing portion 61, so that the mounting is performed. The inside of the portion 62 communicates with the inside of the substrate housing portion 61. An opening end 621 into which the conductor pressing member 7 shown in FIG. 7 is fitted is formed on the rear end side of the conductor pressing attachment portion 62 in the driver housing 6. As shown in FIG. 7, the conducting wire pressing member 7 has a substantially rectangular plate-like base plate portion 71, a holding portion 72 for holding a cap pin 81 (see FIG. 2), a set of lock portions 73, and the like. . The conducting wire pressing member 7 is formed of an insulating member. A belt-like protrusion 622 (see FIG. 6) is provided on the inner surface of the mounting portion 62 so as to go around the inner surface.

  The holding portion 72 of the conductor pressing member 7 has a substantially rectangular parallelepiped shape, and a set of insertion holes 74 through which a cap pin 81 of a cap provided on the circuit board 8 shown in FIG. 2 can be inserted. . The insertion hole 74 is formed so as to penetrate the holding portion 72 and the base plate portion 71 in the thickness direction. By inserting and connecting the base pin 81 to an external socket (not shown) through the insertion port 74 of the conductor holding member 7, power can be supplied to the circuit board 8 from an external power source.

The lock portion 73 of the conducting wire pressing member 7 is erected from the front surface of the base plate portion 71 so as to be along each short side of the holding portion 72. As shown in FIG. 7, a locking claw 75 is formed at the tip of the lock portion 73. Further, a locking groove 76 is formed in the vicinity of the front end portion of the set of side surfaces along the long side direction of the holding portion 72. The locking claw 75 of the lock part 73 and the locking groove 76 of the holding part 72 in the conductor holding member 7 can be engaged with the protrusion 622 formed on the mounting part 62 of the driver housing 6. When the conductor pressing member 7 is fitted into the mounting portion 62 of the driver housing 6, the locking claw 75 and the locking groove 76 are locked to the protrusion 622 formed on the mounting portion 62, so that the conductor pressing member 7 is Mounted on the driver housing 6.

  Next, details of the heat sink 5, the lens 2, the lens holder 3, the LED light emitting module 4 and the like attached to the heat sink 5 will be described. 8 and 9 are perspective views of the heat sink 5 according to the embodiment. The heat sink 5 is a member that constitutes a part of the housing 10 in the lighting device 1 together with the driver housing 6. That is, the housing 10 of the lighting device 1 includes the heat sink 5 and the driver housing 6. The heat sink 5 is also a heat radiating member for cooling the LED 40 by releasing the heat of the LED 40 to the outside. The heat sink 5 is formed of a member having good heat dissipation, such as aluminum.

  The heat sink 5 includes a bottom portion 51 on which the LED light emitting module 4 is installed, an outer cylinder portion 52 located behind the bottom portion 51, a plurality of heat radiation fins 53, and the like. The bottom 51 of the heat sink 5 has a substantially circular planar shape. Further, the inner diameter of the outer cylindrical portion 52 is slightly larger than the outer diameter of the cylindrical wall portion 612 in the driver housing 6, and the cylindrical wall portion 612 can be inserted into the outer cylindrical portion 52. As shown in FIG. 3, the LED light emitting module 4 is installed on the bottom 51 of the heat sink 5.

  The LED light emitting module 4 includes an LED substrate 41 and an LED 40 mounted (mounted) thereon. In the present embodiment, the LED light emitting module 4 is a so-called one-core type module in which the LEDs 40 are arranged in a central portion of the LED substrate 41. That is, the LED light emitting module 4 has the LED 40 mounted on the LED substrate 41 substantially at the center, and is disposed so that the optical axis and the center of the bottom 51 are substantially aligned. The LED substrate 41 is, for example, a metal base substrate formed of a metal material such as aluminum with good heat dissipation or an insulating material. The LED light emitting module 4 radiates heat generated by the LED 40 by being in thermal contact with the heat sink 5.

  The LED 40 has, for example, a chip-on-board structure in which one or a plurality of near-ultraviolet or purple LED chips are directly mounted on a wiring provided on the mounting surface of the LED substrate 41, and is excited by the near-ultraviolet LED or the purple chip. It is configured by being potted by a translucent resin in which a blue phosphor, a green phosphor and a red phosphor emitting light are mixed. As the LED chip, not only a near-ultraviolet or purple LED chip but also various LED chips such as a blue LED chip can be used, and various phosphors can be selected depending on the LED chip to be used. The substrate used for the LED chip is preferably a material having a lattice constant or a coefficient of thermal expansion that is the same as or close to that of the semiconductor material that constitutes the light emitting layer. It is preferable to use nitride semiconductor, silicon carbide, or sapphire. In particular, when the semiconductor material constituting the light emitting layer is a Ga-containing nitride semiconductor, the GaN substrate has almost the same lattice constant and thermal expansion coefficient. This is particularly preferable from the viewpoint of durability and durability. When an LED chip using such a substrate is applied, even if a large current is applied to the LED chip, thermal degradation due to heat generation is small, and long-life LED illumination with a large luminous flux can be realized.

As materials constituting these LED chips, known materials can be appropriately selected according to the purpose and application of the LED bulb, and the LED chips can be manufactured by a known method.
The LED 40 can adopt a package structure instead of using a chip-on-board structure, and can be applied to various forms. In addition, the LEDs 40 may be provided by dispersing a plurality of LEDs 40 on the LED substrate 41.

  The LED light emitting module 4 has a set of fixing screws 42, and the fixing screws 42 can be screwed into fixing portions 613 in the driver housing 6. More specifically, a set of screw insertion holes 511 through which the fixing screws 42 are inserted is formed in the bottom 51 of the heat sink 5. The LED board 41 is formed with a screw insertion hole 43 through which the fixing screw 42 is inserted. After the fixing screw 42 is sequentially inserted into the screw insertion hole 43 of the LED board 41 and the screw insertion hole 511 of the bottom 51 of the heat sink 5, the fixing screw 42 is inserted into a screw groove formed in the fixing portion 613 of the driver housing 6. Screw together. Thereby, the LED substrate 41 in the LED light emitting module 4 can be fixed to the bottom 51 of the heat sink 5. Note that a wiring opening 512 is formed in the bottom 51 of the heat sink 5 for passing a wiring connecting the circuit board 8 and the LED board 41 accommodated in the driver housing 6. Driving power can be supplied to the LEDs 40 mounted on the LED board 41 through wiring from the circuit board 8.

  Next, details of the lens 2 and the lens holder 3 will be described with reference to FIGS. 10 and 11. FIG. 10 is a perspective view of the lens 2 according to the embodiment. FIG. 11 is a perspective view of the lens holder 3 according to the embodiment. The lens holder 3 can hold the lens 2. As shown in FIG. 3, the lens 2 and the lens holder 3 holding the lens 2 are disposed on the bottom 51 of the heat sink 5. Here, the LED light emitting module 4 is installed on the bottom 51 of the heat sink 5. The lens holder 3 holds the lens 2 so that the lens 2 faces the LED 40 of the LED light emitting module 4. The lens 2 is made of, for example, an acrylic resin, and has a substantially truncated cone shape in the example shown in FIG. The lens 2 has an emission surface 21 that emits light emitted from the LED 40 to the front of the lighting device 1 in a state where the lens 2 is attached to the heat sink 5. Of the lens 2, the direction where the emission surface 21 is formed is defined as the front portion of the lens 2. A concave portion 22 for accommodating the lens 2 is formed at a rear portion of the lens 2. The emission surface 21 is, for example, a collimator lens. In addition, a convex lens is provided at the bottom of the concave portion 22 so as to be convex toward the rear portion, for example. The lens is not limited to a collimator lens, and various lenses such as a Fresnel lens can also be preferably used. As shown in FIG. 3, the lens 2 is provided at a position facing the LED 40 mounted on the LED substrate 41, and the lens 2 and the LED 40 are prevented from interfering by accommodating the LED 40 in the recess 22. doing. Note that the shape, size, material, and the like of the lens 2 can be changed as appropriate.

  The lens holder 3 has a substantially cylindrical shape. The lens holder 3 has translucency and is made of, for example, a transparent resin. The lens holder 3 is provided with a cylindrical holder main body 31 and a pair of fixed arm portions 32 extending downward from the holder main body 31. The inner diameter of the lens holder 3 is substantially equal to or slightly larger than the outer diameter of the lens 2, and the lens 2 can be mounted inside the lens holder 3. The fixed arm portion 32 of the lens holder 3 has a hook-shaped connecting claw 33 on the tip side. A set of notches 44 through which the fixed arm portion 32 of the lens holder 3 can be inserted is formed in the LED substrate 41. Also, a set of insertion holes 513 through which the fixed arm portion 32 of the lens holder 3 can be inserted is formed in the bottom 51 of the heat sink 5. The fixed arm portion 32 of the lens holder 3 is sequentially inserted through the notch 44 of the LED substrate 41 and the insertion hole 513 of the heat sink 5, and the connection claw 33 is hooked on the rear surface of the bottom portion 51 of the heat sink 5, thereby The lens holder 3 can be fixed to the lens.

Next, the radiation fins 53 of the heat sink 5 will be described. The heat radiating fins 53 have a plate shape and are arranged radially on the outer peripheral edge of the bottom 51. The heat radiating fins 53 are provided so as to increase the surface area of the heat sink 5 and to easily radiate the heat transferred from the LED 40 to the bottom 51 of the heat sink 5. Each radiating fin 53 is connected to the outer surface of the outer cylinder part 52 and extends radially outward from the side part of the outer cylinder part 52 (in other words, outward from the side part of the bottom part 51). (See FIGS. 8 and 9). The heat radiating fins 53 are radially arranged at regular intervals with respect to the center of the bottom 51 of the heat sink 5. Further, the heat radiating fins 53 extend forward from the bottom 51 with respect to the bottom 51 of the heat sink 5. Here, since the bottom part 51 is located at the front end part of the outer cylinder part 52, it can be said that the radiation fins 53 are provided so as to extend further forward than the outer cylinder part 52. That is, the heat sink 5 according to the present embodiment includes a plurality of plate-like heat radiation fins 53 extending toward the front and side of the bottom 51.

  Here, a portion of the radiating fin 53 that is connected to the outer cylindrical portion 52 is referred to as a “connecting portion 531”. In addition, an edge portion of the radiating fin 53 that is located on the radially outer side of the bottom portion 51 is referred to as an “outer edge portion 532”. As shown in FIGS. 8 and 9, the front end portions of the outer edge portions 532 of the heat radiating fins 53 are connected to each other by an annular rim portion 54. Further, the radiation fin 53 has a “front edge portion 533” extending from the rim portion 54 along the bottom portion 51. Further, the radiating fin 53 has an “inner edge portion 534” extending along the inner surface so as to be substantially flush with the inner surface of the outer cylinder portion 52. The radiating fin 53 has a planar shape defined by the connection portion 531, the outer edge portion 532, the front edge portion 533, and the inner edge portion 534. Note that the positions of the front edge portion 533 and the rim portion 54 of the heat radiating fin 53 generally correspond to the position where the emission surface 31 of the lens 2 is disposed. More specifically, the front edge portion 533 of the radiating fin 53 is inclined obliquely toward the front so as to project forward as the distance from the rim portion 54 increases. In addition, the inner edge 534 of the radiation fin 53 can be referred to as an inner edge in the radial direction of the radiation fin 53.

  As shown in FIG. 3, the illumination device 1 is not covered with the heat radiation fins 53 and is open to the outside in front of the emission surface 21 of the lens 2. Of the light emitted from the LED 40, the light emitted from the emission surface 21 of the lens 2 is emitted forward from the front opening 9 in FIG. Further, as described above, the lighting device 1 is not provided with the outer cylinder portion 52 on the side of the bottom 51 of the heat sink 5 on which the LED light emitting module 4 is installed, and the side of the LED light emitting module 4 is arranged radially. The side opening 11 is formed between the adjacent radiation fins 53 so that the light emitted from the LED 40 is emitted from the side surface of the housing 10 to the outside. In FIG. 4, for the sake of convenience, a dot pattern hatching is added to a portion corresponding to the side opening 11 for the purpose of facilitating understanding of a site where the side opening 11 is formed.

<Simulation>
The lighting device (Example) of the present invention having a rib structure inside the board housing portion of the driver housing and the lighting device (Comparative Example) having the same configuration as the lighting device except that the rib structure is not provided. In order to analyze the temperatures of the LED modules and circuit boards (pseudo-circuits) provided in each of the two lighting devices, the simulation is performed using the fluid analysis software “SolidWorks Flow Simulation” manufactured by Solid Works. It was.
FIG. 12 shows a cross-sectional view of the illumination device (driver housing has a rib structure) used in the simulation. 13 and 14 show a front view and a perspective view of a driver housing (with a rib structure) used in the simulation. 15 and 16 show a front view and a perspective view of a driver housing (without a rib structure) used in the simulation.

(conditions)
The thermal conductivity of each component was calculated as follows.
Lens 2 0.19W / mK
Lens holder 3 0.19W / mK
LED light emitting module 4 400W / mK
Heat sink 5 92W / mK
Driver housing 6 92W / mK
Conductor holding member 7 0.19 W / mK
Circuit board 8 (pseudo circuit) 400W / mK
Potting agent 2W / mK
Moreover, the emissivity of each member was set to 0.95, the environmental temperature and the initial temperature were set to 25 ° C., and calculation was performed in consideration of the influence of gravity. The calorific value was calculated on the assumption that 6 W was generated from the LED light emitting module and 1.8 W was generated from the pseudo circuit.

  Further, in the lighting device (Example) of the present invention, the rib structure existing inside the board housing portion of the driver housing has a structure having seven convex portions only on one side, the convex portion having a width of 1 mm, and the concave portion. The width (interval) was set to 1.2 mm (see FIGS. 13 and 14). On the other hand, in the illumination device of the comparative example, as described above, the rib structure is not present inside the board housing portion of the driver housing (see FIGS. 15 and 16).

(Evaluation of temperature)
The temperature of the LED module and the circuit board (pseudo circuit) included in each lighting device was calculated by simulation. More specifically, the maximum temperature reached on the back surface of the LED module (the surface in contact with the heat sink) and the maximum temperature reached on the pseudo circuit were recorded.

(Evaluation of life)
In general, when an electrolytic capacitor is used in the circuit, it is known that the lifetime of the electrolytic capacitor varies greatly depending on the temperature during use. And it is known that the temperature dependence of the lifetime of the film capacitor follows Arrhenius' law, and the lifetime becomes 1/2 when the temperature increases by 10 ° C. (so-called 10 ° C. rule). Therefore, the relationship between ambient temperature and life can be calculated by the following formula (see <http://www.rubycon.co.jp/products/film/technote_pdf/filmcapacitor4.pdf> ).
L = L ₀ × 2 × (T _max −T _a ) / 10
(However, L is the life in actual use (Hr), L ₀ is the life at the maximum use temperature (Hr), T _max is the maximum use temperature (° C.), and _Ta is the ambient temperature (° C.)).
Therefore, in this embodiment, assuming that the maximum operating temperature T _max is 105 ° C., the life L ₀ at the maximum operating temperature is 8000 hours, and the ambient temperature T ₀ is the above simulation result. The lifetime in actual use was calculated as being consistent with the maximum temperature of a pseudo circuit. That is, the lifetime in actual use was calculated using the following formula.
(Life) = 8000 × 2 × (105− (maximum temperature of the pseudo circuit)) / 10
(Analysis result)
Table 1 shows the calculation results by simulation.

As shown in Table 1, in the embodiment of the present invention, the maximum temperature of the circuit board is suppressed to 89 ° C. by having the rib structure inside the board housing portion of the driver housing. Since it does not have a rib structure, the maximum temperature of the circuit board rose to 92 ° C. As a result, it was found that the life of the capacitor was improved to 25600 hours in the example, compared with 20800 hours in the comparative example, and the life was improved by 23%.
As described above, by using the configuration of the present invention in which the inside of the board housing portion of the driver housing is made of a material having high thermal conductivity and adopts a shape having a rib structure, the heat generated due to the light emission of the LED is reduced. Since it is possible to suppress the temperature rise of the electric circuit itself such as the power supply circuit due to transmission and the like and the thermal deterioration caused thereby, it is effective in realizing both high output and long life of the LED lighting device. .

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Lens 3 Lens holder 4 LED light emitting module 5 Heat sink 6 Driver housing 7 Conductor holding member 8 Circuit board 9 Front opening part 10 Housing | casing 11 Side opening part 21 Outgoing surface 22 Recessed part 31 Holder main body 32 Fixed arm part 33 Engagement Toe Claw 40 LED
41 LED board 42 Fixing screw 43 Screw insertion hole 44 Notch 51 Bottom part 52 Outer cylinder part 53 Radiation fin 54 Rim part 61 Substrate accommodating part 62 Lead wire pressing attachment part 71 Base plate part 72 Holding part 73 Locking part 74 Insertion hole 75 Locking Claw 76 Locking groove 81 Cap pin 511 Screw insertion hole 512 Wiring opening 513 Insertion hole 531 Connection part 532 Outer edge part 533 Front line part 534 Inner edge part 611 Bottom part 612 Cylindrical wall part 613 Fixing part 614 Notch 621 Opening end 622 Protrusion 700 Rib structure

Claims (8)

An LED light emitting module having an LED;
A housing for housing the LED light emitting module;
With
The housing includes a driver housing having a board housing portion for housing a power circuit board for controlling power supplied to the LED, at least in part including a heat sink that dissipates heat generated by the LED.
At least a part of the inside of the substrate housing part has a thermal conductivity of 20 W / mK or more, and at least a part of the inside of the board housing part has a rib structure.   The lighting device according to claim 1, wherein the substrate housing portion is filled with a potting agent.   The lighting device according to claim 1, wherein the board housing portion is not in direct contact with the power circuit board and the power circuit.   The lighting device according to any one of claims 1 to 3, wherein an electrolytic capacitor is mounted on the power circuit board.   The lighting device according to claim 1, wherein a heat radiation paint is coated on an outer side of the driver housing.   The lighting device according to any one of claims 1 to 5, wherein the potting agent has a thermal conductivity of 0.8 W / mK or more.   The lighting device according to claim 1, wherein in the rib structure, the width of the convex portion is within a range of ± 30% of the width of the concave portion.   The lighting device according to claim 1, wherein the LED is an LED chip having at least a substrate and a nitride semiconductor layer on the substrate.

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