JP2013045632A - Led bulb - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED bulb with an improved heat radiation property by convection effect by temperature gradient and an enhanced cooling capacity.SOLUTION: The LED bulb is provided with a cover 3, a bracket 4, a heat radiation member 1, and a base 2 or the like. The heat radiation member 1 is provided with a high radiation part 1a and a low radiation part 1b arranged alternately, and they are formed in a stripe shape. The heat radiation rate of the high heat radiation part 1a is made higher than that of the low radiation part 1b. Since the amounts of radiated heat are differentiated, a temperature gradient between adjacent high radiation part 1a and the low radiation part 1b is formed, and, thereby, a fine convection of air is promoted to enhance a heat radiation property.

Description

  The present invention relates to an LED bulb using a light emitting diode (LED).

  As an alternative to the so-called incandescent bulb, an LED bulb equipped with an LED chip has been proposed. LED lighting devices have advantages such as power saving and long life over incandescent bulbs.

  This LED bulb has an external shape similar to that of a conventional incandescent bulb, and the base as a power supply terminal is equivalent to that of a conventional incandescent bulb. Can also be attached.

  For example, as disclosed in Patent Documents 1 and 2, an LED bulb includes an LED module and a lighting circuit, and is lit by power supply from the lighting circuit. A plurality of LED elements are mounted on the LED module. In addition, an IC chip for power supply and signal control is mounted on the lighting circuit.

  When the LED bulb is turned on, heat generated by the LED chip is mainly conducted from the LED module substrate to the outer member or the housing member, and is radiated to the air from the surface exposed to the outside of the outer member or the housing member. The In this case, for example, as disclosed in Patent Document 1, the outer member and the casing member function as a heat sink.

  By the way, the light output of the LED element decreases as the temperature rises, and the life of the LED element is shorter when the ambient temperature of the LED element is higher. On the other hand, as the light emitting module, a COB (Chip On Board) module in which a plurality of LED chips are densely arranged and mounted on a substrate is used.

  In the case of a COB module, a single light emitting unit is provided and high output light emission is possible. However, since a plurality of LED chips are densely arranged in the light emitting unit, the temperature of the LED chip tends to increase. If the temperature of the LED chip becomes too high, the service life will be shortened and the light output will be reduced. For this reason, it is necessary to efficiently conduct the heat of the LED chip to the housing member or the like and efficiently radiate the air from the surface exposed to the outside of the housing member or the like into the air.

  In order to efficiently dissipate heat from the surface exposed to the outside of the housing member or the like into the air, it is useful to increase the surface area exposed to the outside of the housing member or the like.

  Therefore, as disclosed in Patent Document 2, there is a case in which a plurality of radiating fins are radially formed around a casing member that houses a lighting circuit and an LED module. The heat radiation fin efficiently releases the heat inside the LED bulb to the outside.

JP 2011-82132 A JP 2011-70972 A

  However, the amount of heat generated inside the LED bulb further increases as the number of mounted LED elements and the number of mounted IC chips increase. For this reason, the heat dissipation structure of the LED bulb is required to further improve the heat dissipation performance.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an LED bulb with improved heat dissipation performance.

  In order to achieve the above object, an LED bulb of the present invention includes a light emitting module on which a light emitting diode is mounted, and a cylindrical heat radiating member that is in contact with the light emitting module so as to conduct heat, and the heat radiating member includes: The main feature is that high radiation portions and low radiation portions having different radiation heat amounts are alternately arranged.

  According to the present invention, an LED bulb includes a light emitting module on which a light emitting diode is mounted, and a cylindrical heat radiating member that is in contact with the light emitting module so that heat conduction is possible. The configuration is such that the radiating portions are alternately arranged. For this reason, a temperature gradient is generated between the adjacent high-radiation part and low-radiation part, and convection is generated by this temperature gradient. Accordingly, in a narrow space close to a closed state, such as when an LED bulb is attached to a socket for a bulb, heat dissipation is improved due to the effect of convection due to the temperature gradient.

It is a figure which shows an example of the thermal radiation structure of the LED bulb of this invention. It is a figure which shows the whole general view of the LED bulb | ball with which the radiation fin was attached. It is a figure which shows the structure of the heat radiating member of FIG. It is a figure which shows the A-A 'cross section of FIG. It is a figure which shows the general view of the LED bulb which removed the heat radiating fin. It is a figure which shows the structural example which improved the heat dissipation of the radiation fin. It is a figure which shows the structural example which improved the heat dissipation of the radiation fin. It is a figure which shows the kind of housing | casing used in order to compare heat dissipation. It is a figure which shows the kind of measurement attitude | position regarding heat dissipation measurement. It is a figure which shows the result of having measured heat dissipation using three types of housing | casing of FIG. It is a figure which shows the aluminum plate structure which changed the heat radiation rate alternately. It is a figure which shows the result of having measured heat dissipation using the structure of FIG. 11, and the aluminum plate which carried out the whole black alumite process. It is a figure which shows the structure which covers the measurement object of heat dissipation, and prevents generation | occurrence | production of a convection. It is a figure which shows the result of having measured the heat dissipation about the housing | casing of FIG. 8 in the state which prevented the convection like FIG. It is a figure which shows the result of having performed the heat dissipation measurement about the structure of FIG. 11 in the state which prevented the convection like FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are schematic, and there may be a case where portions having different dimensional relationships and ratios are included between the drawings.

  First, the structural example of an LED bulb is shown in FIGS. 2 is a general view of the entire LED bulb, FIG. 3 is a view showing the structure of the heat dissipation member 10 of the LED bulb, and FIG. 4 is a cross-sectional view taken along line A-A ′ of FIG. The LED bulb includes a cover 3, a bracket 4, a heat radiating member 10, a base 2, and the like. An LED bulb is used by being attached to a lighting fixture for an incandescent bulb, for example, as a substitute product for the incandescent bulb.

  The cover 3 is for protecting the LED module 16 on which the plurality of LED chips 17 shown in FIG. 3 are mounted, and is made of, for example, a transparent or translucent resin. The outer surface of the cover 3 is formed as a smooth surface. The bracket 4 is for facilitating attachment of the cover 3 and the heat radiating member 10. The bracket 4 is made of resin, for example, and is formed in a ring shape.

  The heat radiating member 10 is for radiating the heat from the LED module 16 or the heat from the IC chip into the air, and includes a cylindrical portion 12, a plurality of heat radiating fins 11, and a pedestal portion 15. The heat radiating member 10 is made of, for example, a metal having good heat radiating properties such as aluminum, and is formed by using extrusion or the like.

  The cylindrical portion 12 is formed in a cylindrical shape or the like.

  The plurality of heat radiating fins 11 are formed radially along the radial direction around the central axis Na of the cylindrical portion 12. The plate | board thickness of each radiation fin 11 is comprised so that it may become the same in an up-down direction. Moreover, the adjacent radiation fins 11 are arrange | positioned at fixed intervals. The height h of each radiation fin 11 is formed so as to gradually increase as it approaches the pedestal 15 along the axial direction Na.

  The pedestal 15 is provided at one end in the axial direction Na of the heat radiating member 10 and slightly protrudes from the plurality of heat radiating fins 11 in the axial direction Na. As shown in FIG. 3, the pedestal portion 15 holds a substrate on which the LED module 16 on which the LED chip 17 and the like are mounted is mounted.

  Although not shown, a constant current source that supplies a constant current to the LED element, an IC chip that generates a drive signal for the LED element, and the like are mounted in the hollow portion of the cylindrical portion 12 of the heat radiating member 10. The substrate is inserted in the vertical direction.

  As described above, the heat radiating member 10 releases heat generated from the LED element, the IC chip, and the like to the outside, thereby preventing the temperature inside the LED bulb from rising.

  As described above, increasing the surface area exposed to the outside with the radiation fins 11 to increase the heat radiation amount is effective when the outside is an open space. However, when the LED light bulb is used by being attached to a socket or the like, the external space of the heat dissipation member 10 is a narrow space close to a closed state.

  In this case, since air tends to stay in the space between the heat radiating fins 11, even if heat is radiated due to heat radiation, air convection hardly occurs, and it is considered that heat radiation efficiency is deteriorated.

  Therefore, the LED bulb 100 of the present invention is configured as shown in FIG. 1, for example. The structure which attached | subjected the same code | symbol as FIGS. 2-4 shows the same thing. As described above, the LED bulb 100 includes the cover 3, the bracket 4, the heat radiating member 1, the base 2 and the like. The difference from FIG. 2 is that the heat radiating member 1 is not provided with heat radiating fins. FIG. 5 shows the structure of an LED bulb in which no radiation fins are provided.

  The entire heat dissipating member 1 is made of a metal having good heat dissipation such as aluminum. FIG. 5 differs from FIG. 1 in that the heat dissipating member 1 is surface processed. As shown in FIG. 1, the heat radiating member 1 is provided with alternating high radiating portions 1a and low radiating portions 1b, and is formed in stripes. Referring to FIG. 3, the stripe is formed along the axis Na of the cylindrical portion of the heat radiating member 1. That is, the high radiation portion 1 a and the low radiation portion 1 b are alternately provided in the axial direction of the tubular portion (tubular shape) of the heat radiating member 1.

  The high radiation portion 1a is obtained by increasing the heat radiation rate, for example, by black anodizing the surface of the heat radiating member 1, and the low radiation portion 1b is in a state in which the surface of the heat radiating member 1 is not processed. It is what.

  Thus, the heat radiation rate of the high radiation part 1a is comprised so that it may become larger than the heat radiation rate of the low radiation part 1b. By making a difference in the amount of radiant heat and forming a temperature gradient between the adjacent high radiant part 1a and low radiant part 1b, fine convection of air is promoted and the heat radiation performance or cooling capacity is improved.

  Since it is sufficient that the heat radiation rate of the high radiation part 1a is larger than the heat radiation rate of the low radiation part 1b, the high radiation part 1a is not limited to black alumite processing, but the high radiation part 1a is a region where black paint is applied to the surface of the heat radiation member 1 The low radiation portion 1b may be a region where a white paint is applied to the surface of the heat dissipation member 1.

  In addition, since the thermal emissivity increases when the surface of the material is made uneven, the high radiating portion 1a has a surface where the surface of the heat radiating member 1 is roughened, such as blasting, to form an unevenness. The radiating portion 1b may be a smooth surface.

  Next, it is conceivable to change the structure of the heat dissipating fins 11 in FIG. 2 as a method for forming a temperature gradient by differentiating the amount of radiant heat and promoting fine air convection. For example, the structure shown in FIG.

  This is a view corresponding to the structure of FIG. The heat radiating fins are drawn more schematically. The radiating fins arranged radially from the axis of the cylindrical portion 12 are composed of high radiating fins 11a and low radiating fins 11b.

  The height L1 of the high radiation fin 11a is formed higher than the height L2 of the low radiation fin 11b. Moreover, the thickness L4 of the high radiation fin 11a and the low radiation fin 11b is the same. Furthermore, the high radiation fin 11a and the low radiation fin 11b which adjoin each other are arrange | positioned at intervals L3. If comprised in this way, the surface area of the high radiation fin 11a will become larger than the surface area of the low radiation fin 11b, and the radiation heat amount of the high radiation fin 11a will become larger than the radiation heat amount of the low radiation fin 11b. In this way, a temperature gradient is intentionally generated between the adjacent high radiation fins 11a and low radiation fins 11b to promote fine air convection and improve heat dissipation.

  Here, as a specific numerical example, it can be manufactured with L1 = 7 mm, L2 = 4.5 mm, L3 = 1.6 mm, and L4 = 1.5 mm.

  On the other hand, it may be as shown in FIG. The heat radiating fins arranged radially from the axis of the cylindrical portion 12 are composed of a high radiation fin 11c and a low radiation fin 11d. The height and thickness of the high radiation fin 11c and the low radiation fin 11d are the same. That is, the high radiation fin 11c and the low radiation fin 11d have the same surface area.

  Further, the adjacent high radiation fins 11c and low radiation fins 11d are all arranged at equal intervals. Thus, unlike FIG. 6, the surface area of the high radiation fin 11c and the surface area of the low radiation fin 11d are equal, but the high radiation fin 11c and the low radiation fin 11d are configured to have different thermal emissivities.

  As in the case of the heat dissipating member 1 in FIG. 1, the high radiation fins 11c are formed by black alumite processing. On the other hand, the low radiation fin 11d is formed of a normal fin that has not been subjected to black alumite processing. Thus, the heat radiation rate of the high radiation fin 11c is larger than the heat radiation rate of the low radiation fin 11d. That is, the radiant heat amount of the high radiating fin 11c is larger than the radiant heat amount of the low radiating fin 11d.

  Further, the high radiation fin 11c may be formed by applying a black paint or forming irregularities by roughening the surface. On the other hand, the low radiation fin 11d may be configured by applying a white paint or a smooth surface. In this manner, a temperature gradient is intentionally generated between the adjacent high radiation fins 11c and low radiation fins 11d to promote air convection and improve heat dissipation.

  In order to evaluate the heat dissipating member having the structure shown in FIG. 1, FIG. 6, and FIG. First, in order to evaluate the heat dissipating member in FIG. 6, how much the heat dissipating property was changed due to the difference in the structure of the heat dissipating fin shown in FIG. 8.

  In the heat radiation measurement, a COB (Chip On Board) substrate for LED bulbs in which a plurality of LED chips are densely arranged and mounted on the substrate was used as the heat source 30, and this was adhered to the base portion 21 with heat conductive grease. Two of these were used so that two could be measured simultaneously. A constant current of 300 to 341 mA was used as the current flowing through the heat source 30. The measurement temperature was measured by comparing the temperature of the solder of the LED chip in consideration of the adhesive variation. Since two systems are used for the measurement as described above, the measurement was performed with both measurement systems in consideration of the variation. Furthermore, in order to stabilize the state of the outside air, the measurement object was placed in a box and measured.

  In FIG. 8A, the temperature was measured by installing a heat radiating plate 22 made of aluminum having the same height, the same thickness, and the same depth as the base 21. That is, the surface area of each heat sink 22 is the same. Specifically, the height H1 = 25 mm, the depth length is 30 mm, the thickness of the heat sink 22 is 1.6 mm, and the installation interval of the heat sinks 22 is 4.8 mm. A heat source 30 is bonded to the lower portion of the base 21. The structure of FIG. 8A is assumed to be a casing X1.

  In FIG. 8B, the temperature was measured by alternately installing the heat radiating plates 22 and the heat radiating plates 23 having different heights with respect to the base 21. The heat sink 22 and the heat sink 23 have the same thickness and the same depth. That is, the surface area of the heat sink 22 is larger than the surface area of the heat sink 23. This heat sink 22 is the same as the heat sink 22 in FIG. The heat sink 23 has a height H2 = 15 mm, a depth length of 30 mm, and a thickness of 1.6 mm. The installation interval between the heat sink 22 and the heat sink 23 is 4.8 mm. A heat source 30 is bonded to the lower portion of the base 21. The structure of FIG. 8A is referred to as a housing X2. Moreover, the occupied volume of the housing | casing X1 and the housing | casing X2 is the same.

  In FIG. 8C, the temperature was measured by installing a heat sink 24 with respect to the base 21. The heat sink 22 and the heat sink 24 have the same thickness and the same depth. Further, the height H3 of the heat sink 24 is larger than the height H2 of the heat sink 23 and smaller than the height H1 of the heat sink 22. That is, H2 <H3 <H1. The height H3 of the heat radiating plate 24 is specifically 21 mm. The installation interval of the heat sink 24 is 4.8 mm, similar to the heat sink 22. The structure in FIG. 8C is referred to as a housing X3. The surface area of the housing X2 is the same as the surface area of the housing X3. Moreover, each heat sink has a rectangular shape.

  About the measurement of the heat dissipation of Fig.8 (a)-FIG.8 (c), in order to stabilize the state of external air, it measured by installing housing | casing X1-X3 in a box. When installing in the box, the direction of convection changes depending on the state of the measurement posture. Therefore, measurement was performed in each of the three types of postures shown in FIG. FIG. 9 is a diagram showing three types of patterns for the measurement posture, and shows the case X2 in FIG. 8B as an example.

  FIG. 9A shows a pattern in which the base portion 21 is installed on the bottom surface side of the box and the radiator plates 22 and 23 face the top surface of the box. The posture in FIG. FIG. 9B shows that the other side surface of the heat radiating plates 22 and 23 is the box so that the side surface of the heat radiating plates 22 and 23 faces the bottom side of the box from the posture of FIG. 9A. It is a pattern to be installed so as to face the upper surface. The posture in FIG. 9C, the housing is laid down from the posture of FIG. 9A, and among the plurality of heat sinks, the heat sink 22 at the other end is disposed such that the heat sink 22 at one end faces the bottom surface of the box. This is a pattern that is installed so that the side face of the box faces the top surface of the box. Assume that the posture in FIG.

  FIG. 10 shows the measurement results of the casings X1 to X3 in FIG. 8 while changing to the postures A to C in FIG. The heat source 30 was measured by passing a constant current of 341 mA. The temperature in the box at the time of measurement was 26.6 ± 0.3 ° C. As can be seen from FIG. 10, the measurement average value in the case A of the case X1 is 69.8 ° C., the measurement average value in the case A of the case X2 is 70.5 ° C., and the posture A of the case X3 The measured average value in this case is 71.9 ° C. Further, the measurement average value in the case B of the case X1 is 63.9 ° C., the measurement average value in the case B of the case X2 is 66.9 ° C., and the measurement average value in the case B of the case X3 Is 68.4 ° C. Also, the measurement average value in the case C of the case X1 is 71.3 ° C., the measurement average value in the case C of the case X2 is 70.5 ° C., and the measurement average value in the case C of the case X3 Is 68.4 ° C.

  Here, as described above, the housing X1 has a larger surface area (heat dissipation area) than the housings X2 and X3, and the surface areas of the housing X2 and the housing X3 are the same. That is, it can be seen that in an open space, the amount of radiant heat is more effective for heat dissipation than air convection. However, with the same surface area, the housing X2 in which the heat sinks of different heights are alternately arranged has higher heat dissipation than the housing X3. Further, in the posture C, the temperature of the housing X2 is the lowest, and it can be said that the heat dissipation is the best.

  As can be seen from the comparison between the housing X2 and the housing X3, in the case of the same surface area, the heat dissipating ability is improved by alternately disposing heat sinks having different heights. This is considered to be an effect due to the occurrence of fine convection between the heat radiating plate 22 and the heat radiating plate 23 because the amount of radiant heat differs between the heat radiating plate 22 and the heat radiating plate 23 adjacent to each other. The occupied volume is larger in the case X2, but it is effective for reducing the weight.

  Air convection normally occurs in the vertical direction, but as can be seen from the measurement results of posture C, the case X2 that generates fine convection between heat sinks of different heights is effective in the state where large convection is likely to be hindered. It is considered to be the target.

  Next, heat dissipation was examined for a structure in which the difference in the amount of radiant heat was generated by the difference in thermal radiation rate. This corresponds to the evaluation of the heat radiating member having the structure shown in FIGS. As shown in FIG. 11, black alumite processing was formed with a width of 5 mm and a width of 10 nm on an aluminum plate 40 having a thickness of 3 mm, a horizontal length of 80 mm, and a vertical length of 30 mm.

  FIG. 11A includes a high radiation portion 41 and a low radiation portion 42 formed on the aluminum plate 40. The high radiation portion 41 is a region where black alumite is processed, and the low radiation portion 42 is a region which is not processed and remains aluminum. Therefore, the heat radiation rate of the high radiation part 41 is larger than the heat radiation rate of the low radiation part 42. The high radiation part 41 and the low radiation part 42 are alternately formed in stripes with a width of 10 mm. The structure of FIG. 11A is referred to as structure Y2.

  FIG. 11B includes a high radiation portion 43 and a low radiation portion 44 formed on the aluminum plate 40. The high radiation part 43 is an area where black alumite is processed, and the low radiation part 44 is an area which is not processed and remains aluminum. Therefore, the thermal radiation rate of the high radiation part 43 is larger than the thermal radiation rate of the low radiation part 44. The high radiation portions 43 and the low radiation portions 44 are alternately formed in stripes with a width of 5 mm. The structure in FIG. 11B is referred to as structure Y3.

  Also, a structure in which the entire surface on one side of the aluminum plate 40 is subjected to black alumite processing and the entire surface becomes black is referred to as structure Y1.

  With respect to the structures Y1, Y2, and Y3 made of the aluminum plate 40, heat dissipation was measured. As in the case of FIG. 8, the heat dissipation was measured by installing the structures Y1 to Y3 in a box in order to stabilize the outside air state. When installing in the box, the direction of convection changes depending on the state of the measurement posture. Therefore, each of the three postures in FIG. 9 was used for measurement.

  FIG. 12 shows the results obtained by measuring the structures Y1 to Y3 while changing the postures A to C in FIG. 9 respectively. Although the heat source 30 is not shown in FIG. 11, the heat source 30 was used by being bonded to the bottom of the aluminum plate 40, and a constant current of 341 mA was passed. The temperature in the box at the time of measurement was 25.6 ± 0.3 ° C.

  As can be seen from FIG. 12, the measurement average value for the posture A of the structure Y1 is 76.5 ° C., the measurement average value for the posture A of the structure Y2 is 78.6 ° C., and the measurement is for the posture A of the structure Y3. The average value is 81.2 ° C. In addition, the measurement average value in the posture B of the structure Y1 is 72.8 ° C., the measurement average value in the posture B of the structure Y2 is 74.5 ° C., and the measurement average value in the posture B of the structure Y3 is 77.degree. 5 ° C. Further, the measurement average value in the case of the posture C of the structure Y1 is 73.0 ° C., and the measurement average value in the case of the posture C of the structure Y2 is 75.1 ° C.

  As can be seen by comparing the measured temperature difference between the structures Y1, Y2, and Y3 in the postures A to C and the measured temperature difference between the housings X1, X2, and X3 in FIG. 8, the radiant heat amount is made larger than the convection. Is effective for heat dissipation. Further, the spacing between the stripes of the high emissivity portion and the low emissivity portion formed on the aluminum plate 40 is more effective if it is 5 mm wide, that is, finer.

  However, there is a possibility that air flows into the aluminum plate 40 from a low temperature region in the peripheral portion other than the aluminum plate 40 and a large convection is generated. Even in the cases X1 to X3, there is a possibility that convection in which air enters from the side surface and escapes upward is generated.

  Therefore, as shown in FIG. 13, the enclosure 35 is made of paper, and the measurement object 50 is placed inside the enclosure 35. And it blocks | blocks that the air which flows in from the side surface shown by the direction of an arrow escapes upwards, and prevents a big convection. Temperature measurement was performed for the posture A using the casings X1 and X2 as the measurement object 50. The constant current passed through the heat source 30 was 300 mA. The temperature at the time of measurement was 24.5 ± 0.3 ° C.

  The measurement results are shown in FIG. As a result of inhibiting the convection from the periphery of the casings X1 and X2, the measurement average temperature of the casing X2 was lower. In FIG. 10, in the case of the posture A, the case X1 is in contrast to the fact that the measurement average temperature is lower. That is, when there is no convection due to the inflow of air from the peripheral portion, the above-described fine convection is more effective for heat dissipation than the amount of radiant heat.

  Similarly, temperature measurement was performed for the posture A using the structures Y1, Y2, and Y4 as the measurement object 50. The constant current passed through the heat source 30 was 300 mA. The temperature at the time of measurement was 25.2 ± 0.3 ° C. Here, in the structure Y4, half of the surface area of the aluminum plate 40 in FIG. 11 is blackened by black alumite processing, and the remaining half remains aluminum without being processed. The black high radiant portion area in the structure Y4 and the black high radiant portion area in the structure Y2 are configured to be the same.

  The measurement average temperature of structure Y1 is 86.6 ° C., the measurement average temperature of structure Y2 is 87.8 ° C., and the measurement average temperature of structure Y4 is 89.4 ° C. From this result, in the case of a structure in which the surface of the heat radiating member is not uneven, heat radiation is better when the surface area of the high radiating portion is larger, that is, when the amount of radiant heat is larger. Moreover, when the surface area of the high radiation part is the same, the striped shape has a lower measurement average temperature and better heat dissipation. This is considered to be the effect of fine convection.

  As described above, in an open space, the amount of radiant heat is different from that of the adjacent areas by making a difference in the heat radiation rate and the heat radiation area to form a temperature gradient and generating fine convection. It can be seen that this is more effective for heat dissipation.

  On the other hand, in a narrow space close to a closed state, even if the amount of radiant heat is not increased, the radiant heat amount is made different by changing the heat radiation rate and the heat radiation area in adjacent areas, thereby generating fine convection due to a temperature gradient. It can be seen that this is more effective for heat dissipation.

  Since LED bulbs are used by being embedded in depressions or in an environment where convection is hindered by an umbrella, it is necessary to have a structure as shown in FIGS. It is effective to improve That is, a high radiation portion and a low radiation portion are alternately provided on the heat radiating member, and a temperature gradient is formed between the adjacent high radiation portion and the low radiation portion. Heat dissipation is improved by generating fine convection between the radiating part and each. Further, the structure of the present invention is effective even when used in a sealed container.

DESCRIPTION OF SYMBOLS 1 Heat radiation member 1a High radiation part 1b Low radiation part 2 Base 3 Cover 4 Bracket 10 Heat radiation member 11 Radiation fin 11a High radiation fin 11b Low radiation fin 11c High radiation fin 11d Low radiation fin 12 Cylindrical part 15 Base part

Claims (7)

A light emitting module on which a light emitting diode is mounted;
A cylindrical heat radiation member that is in contact with the light emitting module so as to be able to conduct heat, and
The LED lamp, wherein the heat radiating member includes alternately high radiation portions and low radiation portions having different radiant heat amounts.   2. The high radiation part and the low radiation part are made of materials having different heat radiation rates, and the heat radiation rate of the high radiation part is larger than the heat radiation rate of the low radiation part. LED bulb as described in 2.   The LED light bulb according to claim 2, wherein the high radiation portion and the low radiation portion are provided alternately with respect to a cylindrical axial direction of the heat dissipation member.   4. The LED bulb according to claim 2, wherein the high radiation portion is a region in which a surface of the heat radiating member is processed in black or a region subjected to roughening. 5.   In the heat radiating member, a plurality of heat radiating fins are arranged around the cylindrical axis of the heat radiating member, high radiating fins are alternately arranged as the high radiating portions, and low radiating fins are alternately arranged as the low radiating portions. The LED bulb according to claim 1, wherein   The LED bulb according to claim 5, wherein a surface area of the high radiation fin is larger than a surface area of the low radiation fin.   The LED light bulb according to claim 5, wherein the high radiation fin and the low radiation fin have the same surface area, and the thermal radiation rate of the high radiation fin is larger than the thermal radiation rate of the low radiation fin.

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