JP2011044398A - Led lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED lighting device capable of improving efficiency of illumination of an LED and extending its life by improving heat dissipation effect. <P>SOLUTION: In the LED lighting device 1, the LED which is a light source and a substrate 3 on which the former is mounted are housed in a sealed case 5. The substrate 3 is caused to tightly contact to the point of the sealed case 5 which is exposed to atmosphere. For example, the sealed case 5 consists of a large-diameter cylinder part 5A, a small-diameter cylinder part 5B, and a horizontal part 5C for connecting both 5A and 5B together. The outer periphery of the substrate 3 is caused to tightly contact to the inner surface of the horizontal part 5C, while the LED is mounted on the outer periphery. Further, a plurality of heat dissipation fins 7 are formed on the outer surface of the sealed case 5, and the LED is arranged at the position overlapping with the heat dissipation fin 7 in top view. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an LED illumination device using an LED as a light source.

  FIG. 8 shows an example of an LED lighting device using a power-saving and long-life LED (light emitting diode) as a light source.

  That is, FIG. 8 is a longitudinal sectional view of a conventional LED lighting device, and the illustrated LED lighting device 101 is a disk-like substrate 103 on which a plurality of LEDs 102 (only one is shown in FIG. 8) is mounted. Is housed in a sealed case 105. Here, since the luminous efficiency of the LED 102 is reduced due to heat generation and the lifetime is reduced, aluminum having high thermal conductivity is used for the material of the substrate 103 and the sealing case 105, and a plurality of the outer surfaces of the sealing case 105 are provided on the outer surface. Radiation fins 107 are formed and are devised to suppress the temperature rise of the LED 102 by heat radiation.

  Further, in Patent Document 1, in an LED light bulb, a base on which a substrate on which an LED is mounted and a cover on which the LED is mounted are made of aluminum having high thermal conductivity, and heat generated by lighting the LED is emitted from the substrate. A configuration has been proposed in which the temperature rise of the LED is suppressed by quickly transferring heat to the cover through the base and dissipating heat from the cover.

JP 2008-091140 A

  In the conventional LED lighting apparatus 101 shown in FIG. 8, the heat generated in the LED 102 is conducted radially outward along the first heat conduction path S1 ′, and a part thereof is the second. The heat is dissipated into the atmosphere from the heat radiation fin 107 through the tapered wall 105A of the sealed case 15 along the heat conduction path S2 ′, and the other part of the side wall 105B of the sealed case 105 along the third heat conduction path S3 ′. The first heat conduction path S1 ′ along the substrate 103 that is not exposed to the outside air is long, and heat is radiated in the first heat transfer path S1 ′. Therefore, there is a problem that the inside of the sealed case 105 is heated by the heat transmitted through the long first heat conduction path S1 ′, and it is difficult to effectively suppress the temperature rise of the LED 102.

  Further, even in the configuration proposed in Patent Document 1, the inside of the bulb is heated because the heat conduction path that travels through the base that is not exposed to the outside air is long, and it is difficult to effectively suppress the temperature rise of the LED. There is a problem that there is.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an LED lighting device capable of improving the light emission efficiency and extending the life of the LED by enhancing the heat dissipation effect.

  In order to achieve the above object, according to the first aspect of the present invention, in an LED lighting device in which an LED as a light source and a substrate on which the LED is mounted are accommodated in a sealed case, the substrate is exposed to the atmosphere of the sealed case. It is characterized by being in close contact with the location.

  According to a second aspect of the present invention, in the first aspect of the present invention, the sealed case includes a large-diameter cylindrical portion, a small-diameter cylindrical portion, and a horizontal portion that connects the two, and the inner surface of the horizontal portion includes the substrate. The outer periphery is closely attached, and the LED is mounted on the outer periphery.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a plurality of heat radiating fins are formed on the outer surface of the sealed case, and the LED is disposed at a position overlapping the heat radiating fins in plan view. Features.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the airtight case is formed with a vent hole that guides outside air to the radiating fin.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the vent hole is arranged at a position overlapping the radiation fin in a plan view.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the vent hole is disposed between the LED adjacent to the LED in a plan view.

  According to the first aspect of the present invention, since the substrate is brought into close contact with the portion of the sealed case exposed to the atmosphere, the heat generated in the LED is immediately radiated from the substrate to the outside air through the sealed case, and the LED has a high heat dissipation effect. The temperature rise of the LED is effectively suppressed, and the luminous efficiency of the LED is improved and the lifetime is extended.

  According to the second aspect of the present invention, the heat generated in the LED is obtained from the outer peripheral portion where the LED of the substrate is mounted without passing through the long heat conduction path of the substrate, through the horizontal portion of the sealed case, Conducts sequentially to the small diameter cylinder. And since the horizontal part of the sealed case, the large diameter cylinder part, and the small diameter cylinder part are both exposed to the outside air, the heat conducted through them is immediately dissipated to the outside air, and the temperature rise of the LED is effective due to the high heat radiation effect. To be suppressed.

  According to the invention described in claim 3, since the heat radiation area of the outer surface of the sealed case is increased by the heat radiating fin, the heat conducted from the LED to the sealed case through the substrate is efficiently radiated to the outside air by the high heat radiation effect by the heat radiating fin. The temperature rise of the LED is further effectively suppressed. In addition, since the LED is disposed at a position overlapping the heat radiating fin in plan view, heat from the LED is conducted to the heat radiating fin through the shortest path and efficiently radiated from the heat radiating fin to the outside air.

  According to the fourth aspect of the present invention, the heat radiation fin is cooled by the flow of outside air from the vent hole formed in the sealed case toward the heat radiation fin, so that the heat radiation effect by the heat radiation fin is further enhanced and the temperature of the LED rises. Is more effectively suppressed.

  According to the fifth aspect of the present invention, since the vent hole is disposed at a position overlapping the heat dissipating fin in plan view, the outside air directly hits the heat dissipating fin from the vent hole to cool the heat dissipating fin. For this reason, the heat dissipation effect by the radiation fin is enhanced, and the temperature rise of the LED is further effectively suppressed.

  According to the sixth aspect of the present invention, since the vent hole is disposed while adjacent to the LED in plan view, the LED can be effectively cooled by the outside air passing through the vent hole.

It is a side view of the LED lighting apparatus which concerns on Embodiment 1 of this invention. It is a top view of the LED lighting apparatus which concerns on Embodiment 1 of this invention. It is the sectional view on the AA line of FIG. FIG. 3 is a sectional view taken along line B-B in FIG. 2. It is a top view of the LED lighting apparatus which concerns on Embodiment 2 of this invention. It is CC sectional view taken on the line of FIG. It is a figure similar to FIG. 6 which shows the modification of the LED lighting apparatus which concerns on Embodiment 2 of this invention. It is a longitudinal cross-sectional view of the conventional LED lighting apparatus.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
1 is a side view of an LED lighting apparatus according to Embodiment 1 of the present invention, FIG. 2 is a plan view of the LED lighting apparatus, FIG. 3 is a cross-sectional view taken along line AA in FIG. 2, and FIG. FIG.

  As shown in FIG. 3, the LED device 1 according to the present embodiment includes a disk-shaped substrate 3 on which six LEDs 2 (see FIG. 2) that are light sources are mounted, and a reflector 4 disposed below the disk-shaped substrate 3. Is housed in a sealed case 5. Here, aluminum having high thermal conductivity is used for the material of the substrate 3, the reflector 4, and the sealed case 5. As shown in FIG. 2, six LEDs 2 are arranged on the same circumference on the lower surface of the substrate 3. It is mounted at the same angular pitch (60 ° pitch).

  The lower surface of the sealed case 5 is opened in a circular hole shape, and the opening is closed by a transparent disk-like cover 6 attached so as to support the reflector 4 from below. As shown in FIG. 4, the sealed case 5 includes a large-diameter cylindrical portion 5A formed in the lower portion, and a small-diameter cylindrical portion 5B erected concentrically and vertically above the large-diameter cylindrical portion 5A. The small-diameter cylindrical portion 5B and a horizontal portion 5C that connects the large-diameter cylindrical portion 5A are formed, and a tapered wall 5B1 that extends downward is formed in the lower portion of the small-diameter cylindrical portion 5B. Further, 24 heat dissipating fins 7 extending in the vertical direction are integrally formed radially on the outer surface of the sealed case 5 at an equiangular pitch (15 ° pitch) (see FIG. 2). A base 8 is attached to the upper end of the small diameter cylindrical portion 5B of the sealed case 5.

  Thus, as shown in FIGS. 3 and 4, the substrate 3 on which the plurality of LEDs 2 are mounted has an outer peripheral portion that is in close contact with the inner surface (lower surface) of the horizontal portion 5 </ b> C of the sealed case 5. Six LEDs 2 are arranged on the lower surface of the outer peripheral part in close contact. Moreover, as shown in FIG. 2, each LED2 is arrange | positioned in the position which overlaps with the radiation fin 7 in planar view.

  As shown in FIGS. 4 and 5, the reflector 4 is accommodated inside a large-diameter cylindrical portion 5 </ b> A of the sealed case 5 and seals the sealed case 5 so as to close the circular opening that opens on the lower surface of the sealed case 5. Is supported from below by the disk-like cover 6 attached to the lower surface of the plate. Then, as shown in FIG. 3, at the positions corresponding to the respective LEDs 2 of the reflector 4, the reflection holes 4 a (see FIG. 3) for controlling the light distribution by reflecting the light emitted downward from the respective LEDs 2. (Only one is shown) is formed.

  Thus, in the LED lighting device 1 according to the present embodiment, when each LED 2 that is a light source is energized and each LED 2 emits light, the light passes downward through each reflection hole 4 a of the reflector 4. After the light is reflected and controlled in the process, the light passes through the transparent disk-shaped cover 6 and is irradiated downward for illumination.

  The LED 2 generates heat by light emission, and the heat is conducted from the substrate 3 through the horizontal portion 5C of the sealed case 5 along the first heat conduction path S1 shown in FIG. The part 5 </ b> B is conducted along the second heat conduction path S <b> 2, and these heats are discharged to the outside air by heat radiation from the radiation fins 7. Further, the heat conducted along the first heat conduction path S1 through the horizontal portion 5C of the sealed case 5 is conducted along the third heat conduction path S3 through the large-diameter cylindrical portion 5A of the sealed case 5, and the heat radiating fins. 7 is discharged to the outside air by heat radiation.

  As described above, the heat generated in the LED 2 is conducted from the substrate 3 along the first to third heat conduction paths S1, S2, S3, but the horizontal portion 5C and the large-diameter cylindrical portion 5A of the sealed case 5 and Since the small-diameter cylindrical portions 5B are both exposed to the outside air and the heat radiating fins 7 are formed on the outer surfaces thereof, the heat conducted along the first to third heat conduction paths S1, S2, S3 is radiated. The heat is radiated to the outside air through the fins 7, and the temperature rise of the LED 2 is effectively suppressed by a high heat dissipation effect.

  And in this Embodiment, since LED2 was arrange | positioned in the part closely_contact | adhered to the horizontal part 5C of the airtight case 5 of the board | substrate 2, the heat | fever generate | occur | produced in LED2 does not go through the long heat conduction path | route in the board | substrate 3, but from the board | substrate 3. Immediately conducted along the first to third heat conduction paths S1, S2 and S3 through the horizontal portion 5C of the sealed case 5 to the small diameter cylindrical portion 5B and the large diameter cylindrical portion 5A, the efficiency from the radiation fins 7 to the outside air Dissipates heat well. For this reason, the temperature rise of LED2 is suppressed effectively and the luminous efficiency of this LED2 is improved and the life is extended.

  Further, in the present embodiment, as shown in FIG. 2, each LED 2 is disposed at a position overlapping the radiation fin 7 in a plan view, so that heat from the LED 2 is conducted to the radiation fin 7 through the shortest path and is transmitted from the radiation fin 7. Heat is efficiently radiated to the outside air. Since the heat radiation area of the outer surface of the sealed case 5 is increased by the heat radiation fins 7, the heat conducted from the LED 2 to the sealed case 5 through the substrate 2 is efficiently radiated to the outside air by the high heat radiation effect by the heat radiation fins 7, and the LED 2 The temperature rise is further effectively suppressed.

  In order to confirm the effect of this embodiment, in the LED lighting device 1 according to this embodiment and the conventional LED lighting device 101 shown in FIG. As a result of each determination, it was confirmed that the junction temperature in the LED lighting device 1 according to the present invention was lowered by 111 ° C. and 8 ° C., whereas the junction temperature in the conventional LED lighting device 101 was 119 ° C. .

  In addition, the number of LEDs and heat radiation fins in the LED illumination device is not limited to those shown in the present embodiment, and can be set to the place of assignment.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS.

  FIG. 5 is a plan view of the LED lighting apparatus according to Embodiment 2 of the present invention, and FIG. 6 is a cross-sectional view taken along the line CC of FIG. 5, which is the same as that shown in FIGS. Elements are denoted by the same reference numerals, and description thereof will be omitted below.

  The present embodiment is characterized in that a vent hole 9 for guiding outside air to the radiating fin 7 is formed in the sealed case 5. Specifically, as shown in FIG. 5, vent holes 9 are respectively formed between adjacent LEDs 2 in the plan view of the horizontal portion 5C of the sealed case 5, and a total of six vent holes 9 are formed in the horizontal portion 5C. Are formed on the same circumference. As shown in FIG. 6, each air hole 9 communicates with each of the six air holes 3 a, 4 b, 6 a formed at the corresponding positions of the substrate 3, the reflector 4, and the disc-like cover 6. . Here, as shown in FIG. 5, the air holes 3 a, 4 b, 6 a, and 9 are arranged at positions that overlap with the radiation fins 7 in a plan view.

  Thus, the heat generated in the LED 2 is conducted through the path described in the first embodiment and is finally discharged from the heat radiating fins 7 to the outside air. However, when the sealed case 5 generates heat due to heat conduction, Ascending airflow is generated around the sealed case 5 by convection. Due to the rising airflow, outside air is formed in the disc-shaped cover 6, the reflector 4, the substrate 3, and the airtight holes 6 a, 4 b formed in the sealed case 5, respectively. 3a, 9 passes from below to above and flows toward the heat radiating fins 7. And since the radiation fin 7 is cooled by the flow of this external air, the heat radiation effect by this radiation fin 7 is heightened, and the temperature rise of LED2 is suppressed more effectively. In particular, in the present embodiment, the vent holes 3a, 4b, 6a, 9 are arranged at positions that overlap the heat dissipating fins 7 in a plan view, so that outside air directly enters the heat dissipating fins 7 from these vent holes 3a, 4b, 6a, 9. The heat radiating fins 7 are cooled by hitting them. For this reason, the heat dissipation effect by the radiation fin 7 is enhanced, and the temperature rise of the LED 2 is further effectively suppressed.

  In order to confirm the effect of this embodiment, in the LED lighting device 1 according to this embodiment and the conventional LED lighting device 101 shown in FIG. As a result, the junction temperature in the conventional LED lighting apparatus 101 is 119 ° C., whereas the junction temperature in the LED lighting apparatus 1 according to the present invention is decreased by 109 ° C. and 10 ° C. (Embodiment 1). It was confirmed that the temperature decreased by 2 ° C. with respect to 111 ° C.).

  By the way, in this Embodiment, although the example which used the reflector 4 for light distribution control of the light from LED2 was demonstrated, it replaces with the director 4 and the structure in the case of using the lens 10 is shown in FIG.

  That is, FIG. 7 is a view similar to FIG. 6 showing a modified example of the LED lighting device according to the present embodiment. In this modified example as well, the same number (six pieces) are provided at the same positions of the substrate 3 and the sealed case 5 as described above. ) (Only one is shown in FIG. 7), respectively, and is inserted into the vents 3a and 9 from below at positions corresponding to the vents 3a and 9 of the lens 10. The six ventilation pipes 10A (only one is shown in FIG. 7) are integrally erected, and a ventilation hole 10a is formed therein.

  Therefore, also in this modification, outside air passes through the ventilation holes 10a, 3a, and 9 formed in the ventilation pipe 10A of the lens 10 and the substrate 3 and the sealing case 5, respectively, from the lower side to the upper side, and toward the radiation fins 7. Since the air flows, the heat radiation fin 7 is cooled by the flow of the outside air, the heat radiation effect by the heat radiation fin 7 is enhanced, and the same effect as described above that the temperature rise of the LED 2 is effectively suppressed can be obtained. In this case as well, the vent holes 10a, 3a, and 9 are arranged at positions overlapping the heat radiating fins 7 in plan view.

  The present invention is applicable to LED lighting devices for indoor lighting and outdoor lighting using LEDs as light sources.

1 LED lighting device 2 LED
3 Substrate 3a Substrate ventilation hole 4 Reflector 4a Reflector reflection hole 4b Reflector ventilation hole 5 Sealed case 5A Sealed case large-diameter cylindrical part 5B Sealed case small-diameter cylindrical part 5B1 Small-diameter cylindrical part taper wall 5C Sealed case horizontal part 6 Disc-shaped cover 6a Vent hole in disc-shaped cover 7 Radiation fin 8 Base 9 Vent hole in sealed case 10 Lens 10A Vent pipe of lens 10a Vent hole in lens S1 First heat conduction path S2 Second heat conduction path S3 Third heat conduction path

Claims (6)

In an LED lighting device comprising an LED as a light source and a substrate for mounting the LED in a sealed case,
An LED lighting device, wherein the substrate is brought into close contact with a portion of the sealed case exposed to the atmosphere.   The sealed case is composed of a large-diameter cylindrical portion, a small-diameter cylindrical portion, and a horizontal portion connecting the two, and the outer peripheral portion of the substrate is closely attached to the inner surface of the horizontal portion, and the LED is mounted on the outer peripheral portion. The LED lighting device according to claim 1.   3. The LED lighting device according to claim 1, wherein a plurality of heat radiation fins are formed on an outer surface of the sealed case, and the LED is disposed at a position overlapping the heat radiation fins in plan view.   The LED lighting device according to claim 3, wherein a ventilation hole for guiding outside air to the heat radiating fin is formed in the sealed case.   The LED lighting device according to claim 4, wherein the vent hole is arranged at a position overlapping the heat radiating fin in a plan view. The LED illumination device according to claim 5, wherein the vent hole is disposed adjacent to the LED in a plan view.

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