KR20110101936A - Heat sink and illuminating device having the same - Google Patents

Abstract

A heat sink and a lighting device having the same are provided.
According to an embodiment of the present invention, a heat sink includes a heat dissipation plate having a mounting area in which a driving heating element may be mounted, and having a heat dissipation hole in a central portion thereof; And a plurality of first heat dissipation fins disposed on the other side of the heat dissipation plate and arranged radially along the circumferential direction, and having a length shorter than that of the first heat dissipation fins and disposed between the first heat dissipation fins and arranged radially. It includes; a heat radiation fin having a second heat radiation fin of.

Description

Heat Sink and Illuminating Device Having The Same

The present invention relates to a heat sink capable of improving heat dissipation characteristics of a driving heating element such as a light emitting diode (LED) used as a light source of a lighting device, and a lighting device having the same.

A light emitting device (LED) refers to a semiconductor device capable of realizing various colors of light by configuring a light emitting source by changing compound semiconductor materials such as GaAs, AlGaAs, GaN, InGaInP, and the like.

Such light emitting devices are widely used in various fields such as TVs, computers, lighting, automobiles, etc. due to their excellent monochromatic peak wavelength, excellent light efficiency, miniaturization, eco-friendliness, and low power consumption. It is going out.

Recently, the use of incandescent bulbs, which are low-efficiency lights, is regulated by energy-saving movements, and movements to replace them with high-efficiency lights such as light emitting devices are actively taking place, especially among light emitting device manufacturers and lighting companies.

Lighting devices using such a light emitting device as a light source has a great response due to the advantage that the life is longer than conventional incandescent lamps or halogen lamps.

However, the light emitting device generates a lot of heat in accordance with the increase in the amount of current applied, which causes a problem of lowering the luminous efficiency and shortening the lifespan.

In particular, if the high-temperature heat is not effectively released, the performance of the device as well as the problem occurs, the design of an efficient heat dissipation structure is essential.

Disclosure of Invention An object of the present invention is to provide a heat sink capable of maximizing heat dissipation characteristics for a driving heating element such as a light emitting element used as a light source in an illumination device and a lighting device having the same.

According to an embodiment of the present invention, a heat sink includes a heat dissipation plate having a mounting area in which a driving heating element may be mounted, and having a heat dissipation hole in a central portion thereof; And a plurality of first heat dissipation fins disposed on the other side of the heat dissipation plate and arranged radially along the circumferential direction, and having a length shorter than that of the first heat dissipation fins and disposed between the first heat dissipation fins and arranged radially. It may include; a heat radiation fin having a second heat radiation fin of.

In addition, the heat dissipation fin may be provided extending from the periphery of the heat dissipation plate toward the heat dissipation hole in the center.

In addition, the heat dissipation fin may have a value (L _M / L _L ) of the length L _L of the first heat dissipation fin and the length L _M of the second heat dissipation fin between 0.4 and 0.7.

In addition, the heat dissipation fin may be shorter than the second heat dissipation fin, and may further include a plurality of third heat dissipation fins disposed radially between the second heat dissipation fin and the first heat dissipation fin.

The heat dissipation fin may have a value L _S / L _L of a length L _L of the first heat dissipation fin and a length L _S of the third heat dissipation fin.

The heat dissipation fin may include a cavity in which an end portion extending vertically along the optical axis in the center of the heat dissipation plate is spaced radially at regular intervals with respect to the heat dissipation hole so that air introduced into the center is discharged along the heat dissipation fin. Can be formed.

On the other hand, the lighting device according to an embodiment of the present invention includes a light source module including a light emitting device package and a substrate on which at least one light emitting device package is mounted; A reflector having a front hole with an open front surface and accommodating the light source module therein such that the light emitting device package faces the front hole; A heat dissipation plate mounted on one side of the light source module and the reflector, the heat dissipation plate having a heat dissipation hole at a central portion thereof, a plurality of first heat dissipation fins disposed on the other side of the heat dissipation plate, and arranged radially along a circumferential direction; A heat sink comprising a heat dissipation fin having a plurality of second heat dissipation fins disposed between the first heat dissipation fins and disposed radially between the first heat dissipation fins; And a cover member mounted to the front hole of the reflector to protect the light source module.

In addition, the heat dissipation fin may be provided extending from the periphery of the heat dissipation plate toward the heat dissipation hole in the center.

In addition, the heat dissipation fin may have a value (L _M / L _L ) of the length L _L of the first heat dissipation fin and the length L _M of the second heat dissipation fin between 0.4 and 0.7.

In addition, the heat dissipation fin may be shorter than the second heat dissipation fin, and may further include a plurality of third heat dissipation fins disposed radially between the second heat dissipation fin and the first heat dissipation fin.

The heat dissipation fin may have a value L _S / L _L of a length L _L of the first heat dissipation fin and a length L _S of the third heat dissipation fin.

The apparatus may further include a power supply device mounted on the heat sink to supply power to the light source module.

The reflector may further include a fixing ring mounted on the front hole to prevent the cover member and the light source module from falling in the reflector.

According to the present invention, it is possible to maximize heat dissipation characteristics by inducing smooth air circulation through an optimized arrangement of heat dissipation fins having various lengths.

1 is a perspective view schematically showing a heat sink according to an embodiment of the present invention.
FIG. 2 is a plan view illustrating the heat sink illustrated in FIG. 1.
FIG. 3 is a view schematically showing a flow of air in the heat sink shown in FIG. 1.
4 is a perspective view schematically showing a heat sink according to another embodiment of the present invention.
FIG. 5 is a plan view illustrating the heat sink illustrated in FIG. 4.
6 is a view schematically showing a lighting device according to an embodiment of the present invention.

With reference to the drawings will be described with respect to the heat sink and the lighting device having the same according to an embodiment of the present invention.

However, embodiments of the present invention may be modified in many different forms and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Therefore, the shape and size of the components shown in the drawings may be exaggerated for more clear description, components having substantially the same configuration and function in the drawings will use the same reference numerals.

A heat sink according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

1 is a perspective view schematically showing a heat sink according to an embodiment of the present invention, FIG. 2 is a plan view showing the heat sink shown in FIG. 1, and FIG. 3 shows a flow flow of air in the heat sink shown in FIG. 1. It is a figure which shows schematically.

1 to 3, the heat sink 1 according to the embodiment of the present invention includes a heat dissipation plate 10 and a heat dissipation fin 20.

The heat dissipation plate 10 supports a light source module 200 having at least one light emitting element, which is used as a light source of an illumination device, as a driving heating element to be fixed by being mounted on one side thereof, and generated from the light source module 200. The light source module 200 is cooled by receiving high temperature heat and releasing it primarily.

Therefore, a metal material having excellent thermal conductivity, such as aluminum, for smooth heat dissipation, and may be formed in a circular shape as shown in the drawing, but is not limited thereto. It may be formed in a shape.

In addition, the heat dissipation hole 12 is formed in the center of the heat dissipation plate 10 so that the heat generated from the light source module 200 can directly move to the opposite side of the heat dissipation plate 10.

A plurality of heat dissipation fins 20 are provided on the other side of the side having a mounting area in which the light source module 200 can be mounted on the heat dissipation plate 10, and are arranged radially along the circumferential direction.

As shown in the figure, the heat dissipation fin 20 is formed in a rectangular panel shape, one end of the heat dissipation hole 12 in the center from the periphery of the heat dissipation plate 10 by contacting the heat dissipation plate 10 vertically It is provided with a plurality of structures extending toward).

In particular, the plurality of heat dissipation fins 20 may include a plurality of first heat dissipation fins 21 arranged at regular intervals, and a second heat dissipation fin 22 having a shorter length than the first heat dissipation fins 21. It is characterized in that it is provided between the heat dissipation fins 21 arranged in a radial arrangement. That is, a structure in which the heat dissipation fins having two different lengths, specifically, the first long heat dissipation fin 21 and the shorter second dissipation fin 22 are radially spaced apart from each other at regular intervals. to be.

In this case, the ratio (L _M / L _L) of the length (L _L) and the length (L _M) of the second heat radiating fins 22 of the plurality of heat radiating fins (20) includes a first heat radiation fin 21 is 0.4 It is preferred to have a value between -0.7 and.

In terms of heat transfer, most heat transfer occurs in the heat dissipation fins 20, and as the number of heat dissipation fins 20 increases, the heat transfer area increases to decrease the average temperature of the heat sink. However, the flow path area (A) between the inlet area of the cooling air and the heat dissipation fin is reduced to reduce the flow rate of the cooling air, and the temperature rises rapidly as the cooling air goes to the inner center, so that the temperature difference with the heat dissipation fin 20 is small. Decreases heat transfer. Therefore, as the number of the heat dissipation fins 20 increases, the average temperature of the heat sink increases rather than the increase of the heat transfer coefficient due to the increase in the heat transfer area, but the decrease of the heat transfer coefficient due to the decrease in the air inflow.

Similarly, as the length of the heat dissipation fins 20 increases, the heat transfer area increases, and the average temperature of the heat sink decreases. However, when the length of the heat dissipation fin 20 is greater than or equal to a predetermined length, the average temperature of the heat sink does not decrease any more because the temperature of the cooling air rises toward the center of the heat sink and becomes similar to the temperature of the heat dissipation fin 20. . Therefore, as the length of the heat dissipation fin 20 increases, the heat transfer area increases to increase the heat transfer coefficient. However, as the center heat approaches, the local heat transfer coefficient decreases due to superheated air.

Accordingly, the heat dissipation fin 20 according to the embodiment of the present invention increases the heat transfer area by alternately arranging a plurality of heat dissipation fins 21 and 22 having different length ratios, while at the inflow amount and the center of the cooling air. It is possible to reduce the average temperature of the heat sink by preventing the flow path area A from decreasing.

In addition, the first ratio (L _M / L _L) of the radiation length (L _L) and the second heat radiation length (L _M) of the pin 22 of the pin 21 preferably has a value between 0.4 to 0.7 However, if it is less than 0.4, the heat transfer area is reduced to decrease the heat transfer coefficient. If it is larger than 0.7, the flow path area (A) at the center is narrowed, and the inflow of cooling air is reduced, and the temperature of the cooling air at the center is increased. The average temperature of the heat sink 1 is increased without decreasing.

Meanwhile, as illustrated in FIGS. 2 and 3, the heat dissipation fin 20 has an end portion extending vertically along the optical axis O at the center of the heat dissipation plate 10 radially constant with respect to the heat dissipation hole 12. Spaced at intervals to form a cavity 30 to allow the air introduced into the center along the heat dissipation fin 20 is discharged.

The cavity 30 is intended to easily discharge the heated air to the outside by inducing a chimney effect (Fig. 3), so that the heated cooling air rises in the vertical direction and is easily discharged to the outside.

That is, the cooling air heated by the high temperature heat radiation fins 20 while flowing into the center from the outside of the heat sink 1 is lowered in density than the ambient air, and the cavity is not provided with the heat radiation fins 20. In the region 30), the velocity of the vertical component of the air increases so that the air can be easily released to the outside without being accumulated.

A heat sink according to another embodiment of the present invention will be described with reference to FIGS. 4 and 5.

4 is a perspective view schematically illustrating a heat sink according to another embodiment of the present invention, and FIG. 5 is a plan view illustrating the heat sink shown in FIG. 4.

As shown in the drawing, the heat sink 1 'according to another embodiment of the present invention includes a heat dissipation plate 10 and a heat dissipation fin 20', and the overall structure is substantially the same as the embodiment shown in FIG. . However, in the structure of the heat dissipation fin 20, the length of the heat dissipation fin 20 is shorter than that of the second heat dissipation fin 22 in addition to the first heat dissipation fin 21 and the second heat dissipation fin 22. The plurality of third heat dissipation fins 23 may be further disposed between the first heat dissipation fins 21 and arranged radially.

Specifically, in the heat sink 1 ′ according to the present embodiment, the heat dissipation fins 20 ′ have a plurality of first heat dissipation fins 21 radially arranged at regular intervals, and are longer than the first heat dissipation fins 21. The second heat dissipation fins 22 are arranged between the first heat dissipation fins 21 and are arranged radially, and the third heat dissipation fins 23 having a shorter length than the second heat dissipation fins 21 are formed. It is arrange | positioned between the 1st heat radiation fin 21 and the 2nd heat radiation fin 22, respectively, and is arrange | positioned radially. That is, between the heat radiation fins 20 'having three different lengths, specifically, the third heat radiation fins 23 of the shortest length, the long heat radiation fins 21 and the second heat radiation fins of medium length ( 22) are alternately spaced at regular intervals and are provided radially.

In this case, the plurality of heat dissipation fins 20 ′ is a ratio L _S / L _L of the length L _L of the first heat dissipation fin 21 and the length L _S of the third heat dissipation fin 23. It is preferable to have this value below 0.2. When the length ratio has a value of 0.2 or more, as described above, the flow path area A between the inlet area of the cooling air and the heat dissipation fin is narrowed, so the inflow of the cooling air is reduced.

In the following, the computational heat transfer analysis is compared with the heat dissipation performance test results for the heat sink to verify its validity, and looks at the optimization conditions of the heat sink according to an embodiment of the present invention.

<Comparison of Experimental Results and Computational Heat Transfer Analysis>

-Heat dissipation performance experiment

In order to test the heat dissipation performance of the 6 inch 20W mass-production model, an aluminum heat sink consisting of 20 heat dissipation fins, specifically 20 first heat dissipation fins, was used for the experiment.

The temperature was measured using a T type thermocouple, and a thermal imaging camera was used to examine the emissivity and overall temperature distribution. In this experiment, the emissivity was indirectly corrected by changing the emissivity to the same temperature as measured by the thermocouple while changing the emissivity. The temperature measurement was performed after powering on the LED module and reaching a steady state with little change in temperature.

-Computational Heat Transfer Analysis

Like the heat sink used in the experiment, the average temperature was analyzed by modeling a heat sink having 20 radiating fins 20, a radius of 75 mm, and a radiating fin 20 having a length of 55 mm.

In numerical analysis, the SIMPLE algorithm was selected to solve the flow field by combining pressure and velocity, and only natural convective heat transfer was considered. In order to verify the validity of the heat transfer analysis through the numerical analysis, the experimental results and the analysis results were compared in [Table 1].

Experiment result (℃) Computerized heat transfer analysis result (℃) Average temperature of heat sink 38.8 39.48 Outside temperature 18.5 18.5

As shown in [Table 1], it can be seen that the experimental results and the computational heat transfer analysis results are almost identical, and thus, the computational heat transfer analysis method is valid.

<Optimization of heat sink>

Based on the above results, the heat sink with excellent heat dissipation performance was optimized through computational heat transfer analysis. First of all, the average temperature was compared by using three models to select the optimization model.

The LMS model includes a first heat dissipation fin 21 having a long length, a second heat dissipation fin 22 having a medium length, and a third heat dissipation fin 23 having a short length, and 20 first heat dissipation fins 21, Twenty second heat dissipation fins 22 and 40 third heat dissipation fins 23 are provided. The LM model includes a first heat dissipation fin 21 and a second heat dissipation fin 22, and each of 20 LM models is provided. The L model includes only the first heat dissipation fin 21 and 20 pieces are provided.

LMS LM L Average temperature of heat sink 39.3 ℃ 36.6 ℃ 38.8 ℃ Outside temperature 20.2 ℃ 18.5 ℃ 18.5 ℃ Average temperature difference 19.1 ℃ 18.1 ℃ 20.3 ℃

The heat dissipation area is the largest in the LMS model, but the average temperature of the heat sink is lowest in the LM model. In the case of the LMS model, the heat dissipation area is relatively increased by having the third heat dissipation fin 23, but it hinders air flow between the heat dissipation fins.

Based on these analysis results, the combination of heat sink fins was performed based on the LM model to optimize the heat sink structure. In performing the optimization, the design variables were the number of the heat dissipation fins 20 and the length of the second heat dissipation fins 22, and the objective function was selected as minimizing the average temperature of the heat sink. The fixed variable was selected as the length of the first heat dissipation fin 21, the diameter of the heat dissipation plate 10, and the height of the heat dissipation fin 20. In the optimization, the central composite design calculated the number of heat dissipation fins and the length of the second heat dissipation fin 22 in which the average temperature of the heat sink had the minimum value.

The diameter of the heat dissipation plate 10 is 6 to 8 inches, the length of the first heat dissipation fin 21 is 0.6 to 0.8 times the radius of the heat dissipation plate, the height of the heat dissipation fin is 21.3 mm, the calorific value is 700 W / m ² , and the outside temperature is Calculated at 30 ° C., the results are shown in [Table 3].

inch L _L (mm) L _M (mm) No. of fins T _avg (℃) L _M / L _L 6 55 30 40 57.41 0.55 6 45 21 48 57.56 0.47 7 69 40 48 60.34 0.58 7 59 33 48 60.01 0.56 8 77 42 48 62.70 0.55 8 67 38 48 62.64 0.58

As described above, in the case of the 6-8 inch heat sink, the optimized structure includes a heat dissipation fin having two lengths, specifically, a first heat dissipation fin 21 and a first heat dissipation plate. 2 is a structure in which the heat dissipation fins 22 are alternately spaced at regular intervals and are provided radially. In this case, an optimal value of the number of heat dissipation fins is 40 to 48, and the second heat dissipation fin 22 and the first heat dissipation fin 21 are 21. It can be seen that the length ratio (L _M / L _L ) of) has a value between 0.4 and 0.7.

Meanwhile, in addition to the LM model described above, an LMS model further including a third heat dissipation fin 23 may be employed. In this case, the length L _L of the first heat dissipation fin 21 and the third heat dissipation fin 23 may be adopted. It is preferable that the ratio (L _S / L _L ) of the length L _{S of} )) has a value of 0.2 or less.

A lighting device having a heat sink according to an embodiment of the present invention will be described with reference to FIG. 6.

6 is a view schematically showing a lighting device according to an embodiment of the present invention.

Referring to FIG. 6, the lighting apparatus 100 according to the embodiment of the present invention includes a light source module 200, a reflector 300, a heat sink 1, and a cover member 400, and a power supply device ( It may further include a PSU (500).

The light source module 200 includes a light emitting device package 220 and a substrate 210 on which at least one light emitting device package 220 is mounted.

In particular, the light source module 200 uses a light emitting device (LED), which is a kind of semiconductor device that emits light of a predetermined wavelength by a power source applied from the outside, and uses the light emitting device package 220 as the light emitting device. It has one or more inside.

The substrate 210 is a kind of printed circuit board (PCB) formed of an organic resin material containing epoxy, triazine, silicon, polyimide and the like, and other organic resin materials, or a ceramic material such as AlN, Al ₂ O _3, or the like. Or, it may be formed of a metal and a metal compound as a material, specifically MCPCB which is a kind of metal PCB is preferable.

Circuit lines (not shown) electrically connected to the light emitting device package 220 are provided on the opposite surface of the substrate 210 on which the light emitting device package 220 is mounted.

The reflector 300 includes a front hole 310 having an open front surface, and accommodates the light source module 200 therein such that the light emitting device package 220 faces forward through the front hole 310. do.

The inner circumferential surface 320 of the reflector 300 is formed in an inclined surface structure which is inclined at a predetermined inclination toward the front hole 310 from a bottom surface on which the light source module 200 is accommodated so that light generated in the light source module 200 is generated. Guides toward the front of the lighting device, and allows the reflected light to be emitted to the outside through the front hole 310.

The cover member 400 is mounted to the front front hole 310 of the reflector 300 to protect the light source module 200. The cover member 400 may be formed of a material such as plastic, silica, acrylic, glass, etc., and is preferably formed to be transparent for light transmission.

In addition, the cover member 400 may contain a fluorescent material for converting the wavelength of the light emitted from the light emitting device package 220, and may contain a light dispersing material for the diffusion of light.

The reflector 300 further includes a fixing ring 600 mounted on the front hole 310 to prevent the cover member 400 and the light source module 200 from falling within the reflector 300. Do it. The fixing ring 600 is preferably mounted in a detachable structure, and thus can easily replace the cover member 400 or the light source module 200.

The rear surface (or bottom surface) of the reflector 300 is coupled to the heat sink 1 together with the light source module 200. Specifically, the reflector 300 has a structure in which a rear surface thereof is closed to form a cavity together with the inner circumferential surface 320, and the light source module 200 is provided in the reflector 300. It is mounted on the heat dissipation plate 10 of the heat sink 1 via 300.

Without being limited to this, the reflector 300 may have a structure in which a rear surface thereof is opened to penetrate the reflector 300 together with the front hole 310. In this case, the light source module 200 is the heat. Directly mounted on the heat dissipation plate 10 of the sink 1, the reflector 300 may be mounted on the heat dissipation plate 10 in a structure surrounding the light source module 200.

Since the heat sink 1 has been described in detail with reference to FIGS. 1 to 5, a description thereof will be omitted.

On the other hand, the power supply device 500 is mounted on the heat sink 1 to power to the light emitting device package 220 through a circuit wiring not shown in the substrate 210 of the light source module 200 To supply.

Specifically, the power supply device 500 is provided on the heat dissipation fin 20 of the heat sink 1 and the circuit wiring of the substrate 210 through the heat dissipation hole 12 of the heat dissipation plate 10. It may be electrically connected, and may include SMPS.

1,1 '...... heat sink 10 ........ heat dissipation plate
12 ........ Heat dissipation hole 20 ........ heating fin
21 ........ 1st heat dissipation fin 22 ........ 2nd heat dissipation fin
23 ........ 3rd Heat Dissipation Fin 30 ........ Cavity
100 ....... Lighting device 200 ....... Light source module
210 ....... substrate 220 ....... light emitting device package
300 ....... Reflective part 310 ....... Front hole
400 ....... Cover member 500 ....... Power supply
600 ....... retaining ring

Claims (13)

A heat dissipation plate having a heat dissipation hole formed at a center thereof, and a mounting area in which a driving heating element is mounted on one side thereof; And
A plurality of first heat dissipation fins disposed on the other side of the heat dissipation plate and arranged radially along the circumferential direction, and a plurality of first heat dissipation fins shorter than the first heat dissipation fins and disposed between the first heat dissipation fins and arranged radially; A heat dissipation fin having a second heat dissipation fin;
Heat sink comprising a.
The method of claim 1,
The heat dissipation fin is a heat sink, characterized in that extending from the periphery of the heat dissipation plate toward the heat dissipation hole in the center.
The method of claim 1,
The heat dissipation fin is heat, characterized in that the ratio (L _M / L _L ) of the length (L _L ) of the first heat dissipation fin and the length (L _M ) of the second heat dissipation fin has a value between 0.4 and 0.7. Sink.
The method of claim 1,
The heat dissipation fin has a shorter length than the second heat dissipation fin, and further includes a plurality of third heat dissipation fins disposed radially between the second heat dissipation fin and the first heat dissipation fin.
The method of claim 4, wherein
The heat dissipation fin is a heat sink, characterized in that the ratio (L _S / L _L ) of the length (L _L ) of the first heat dissipation fin and the length (L _S ) of the third heat dissipation fin has a value of 0.2 or less.
The method according to claim 1 or 4,
The heat dissipation fins are formed at a center portion of the heat dissipation plate, the ends extending vertically along the optical axis to be spaced at regular intervals radially with respect to the heat dissipation holes to form a cavity for discharging air introduced into the center along the heat dissipation fins. Heat sink, characterized in that.
A light source module including a light emitting device package and a substrate on which at least one light emitting device package is mounted;
A reflector having a front hole with an open front surface and accommodating the light source module therein such that the light emitting device package faces the front hole;
A heat dissipation plate mounted on one side of the light source module and the reflector, the heat dissipation plate having a heat dissipation hole at a central portion thereof, a plurality of first heat dissipation fins disposed on the other side of the heat dissipation plate, and arranged radially along a circumferential direction; A heat sink comprising a heat dissipation fin having a plurality of second heat dissipation fins disposed between the first heat dissipation fins and disposed radially between the first heat dissipation fins; And
A cover member mounted to the front hole of the reflector to protect the light source module;
Lighting device comprising a.
The method of claim 7, wherein
And the heat dissipation fin extends from the periphery of the heat dissipation plate toward the heat dissipation hole in the center portion.
The method of claim 7, wherein
The heat dissipation fin is characterized in that the ratio (L _M / L _L ) of the length L _L of the first heat dissipation fin and the length L _M of the second heat dissipation fin has a value between 0.4 and 0.7. Device.
The method of claim 7, wherein
The heat dissipation fin has a shorter length than the second heat dissipation fin, and further includes a plurality of third heat dissipation fins disposed radially between the second heat dissipation fin and the first heat dissipation fin.
The method of claim 10,
The heat dissipation fin is an illumination device, characterized in that the ratio (L _S / L _L ) of the length (L _L ) of the first heat dissipation fin and the length (L _S ) of the third heat dissipation fin has a value of 0.2 or less.
The method of claim 7, wherein
And a power supply unit mounted on the heat sink to supply power to the light source module.
The method of claim 7, wherein
The reflector further comprises a fixing ring mounted on the front hole to prevent the cover member and the light source module from falling in the reflector.

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