JP2013229396A - Heat sink and luminaire including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sink having enhanced heat dissipation performance, and to provide a luminaire which can be made compact and light weight.SOLUTION: In a heat sink 10 for cooling an LED (heat source) 2 on the surface of a base plate 11, having a plurality of heat dissipation fins 12 standing on the back face, by natural convection, interval of the heat dissipation fins 12 is set to widen from the upstream toward the downstream of natural convection. The heat dissipation fins 12 are formed to spread radially from the width direction center at the upstream side end of natural convection toward the downstream of natural convection. Some of a plurality of air passages 13, formed between the heat dissipation fins 12, are opening to the right and left of the natural convection direction. An LED luminaire 1 is constituted by mounting an LED (light-emitting element) 2 on a substrate 3 that is provided on the surface of the base plate 11 of the heat sink 10, or on the surface of the base plate 11.

Description

  The present invention relates to a heat sink in which a plurality of heat radiating fins are erected on the back surface of a base plate on which a light emitting element such as an LED is mounted as a heat source, and an illumination device including the heat sink.

  In recent years, as the power consumption of semiconductors has increased at an accelerated rate, the amount of heat generated by the semiconductors has increased, and thus there has been an increasing demand for high-performance cooling systems. In addition, even in a circuit integrated at a high density for miniaturization, the power consumed tends to increase, and the heat generation density increases rapidly at the same time as the heat generation amount.

  In light-emitting elements such as LEDs (light-emitting diodes) and laser diodes, which are semiconductors, as the brightness has increased, the number of applications for lighting has increased from that for conventional displays, and the power consumption has been increasing. is there.

  However, the biggest problem with light-emitting elements such as LEDs is that most of the input electric power becomes heat, and the light emission efficiency and life are reduced by the heat generated by itself. In particular, a light-emitting element that consumes a large amount of power is required to have a heat dissipation structure capable of receiving heat generation of several watts per chip. In order to conduct this heat generation, instead of a conventional resin substrate, heat conductivity is required. High metal core substrates and ceramic substrates have been put into practical use.

  Also, a cooling structure that suppresses heat generation of the LED by heat radiation by a heat sink in which a plurality of heat radiation fins are erected on the back surface of the base plate has been put into practical use. Here, an example of the cooling structure by the heat sink of the conventional LED lighting apparatus is shown in FIG.

  That is, FIG. 4 is a diagram showing an example of a cooling structure using a heat sink of a conventional LED lighting device, where (a) is a front view, (b) is a plan view, and (c) is a line MM of (a). Sectional drawing, (d) is a side view, (e) is a rear view, (f) is a perspective view, and the heat sink 110 of the LED lighting apparatus 101 is made of an aluminum alloy having a high thermal conductivity and is rectangular. On the back surface of the plate-shaped base plate 111, a plurality of rectangular plate-shaped (20 in the illustrated example) radiating fins 112 that are long in the vertical direction are vertically arranged at appropriate intervals in the horizontal direction. On the surface of the heat sink 110, a rectangular plate-like substrate 103 is mounted which is mounted with a total of nine LEDs 102 in three rows and columns. The substrate 103 and the LEDs 102 mounted on the substrate 103 are rectangular outer lenses. 104.

  Thus, when the nine LEDs 102 are energized and emit light, the heat generated from the LEDs 102 is conducted from the base plate 111 of the heat sink 110 to the radiation fins 112 and is radiated from the radiation fins 112 into the air. As a result, the LED 102 is cooled and the temperature rise is suppressed.

  Incidentally, in Patent Document 1, in a heat sink by natural air cooling, a plurality of fins are erected along at least one of a front surface and a back surface of a base formed in a substantially vertical direction and formed between these fins. A configuration has been proposed in which natural air cooling with a high cooling capacity is realized even in a narrow space where it is difficult to mount cooling fins by widening the width of the heat convection space as it moves away from the substrate.

  Further, in Patent Document 2, in a cooling structure that employs a forced air cooling method using a cooling fan, a sufficient heat dissipation effect can be obtained even at a location away from the cooling fan by forming the shape of the radiation fins higher as the distance from the cooling fan increases. A configuration that can be obtained has been proposed.

JP 2010-251730 A Japanese Patent Laid-Open No. 7-249885

  In the conventional heat sink 110 shown in FIG. 4, in order to improve the heat dissipation performance, it is necessary to increase the size of the heat sink 110 to increase the heat dissipation area. There arises a problem that 101 becomes larger and heavier.

  Further, the heat sink 110 has a problem that the heat dissipation performance due to convection is lowered depending on the installation direction of the heat sink 110. In particular, when the heat sink 110 is attached so that the base plate 111 of the heat sink 110 is perpendicular to the air convection direction (from bottom to top), the air rising from the bottom is blocked by the upper base plate 111 and the side radiation fins 112. As a result, the convection is stagnated, and the convection effect by the radiating fins 112 is not sufficiently exhibited. Therefore, the heat dissipation of the heat sink 110 is lowered, and a temperature distribution occurs in each LED. Specifically, in the temperature distribution in the left-right direction, the center LED is at a higher temperature because it is located at a position farther from the cooler outside air. Further, in the vertical direction, the upper LED is warmed by the outside air received at the lower side, and thus the temperature is higher.

  The configuration proposed in Patent Document 1 is based on the premise that the base surface and fin surface of the heat sink are in the vertical direction, and the base surface and fin surface of the heat sink are perpendicular to the air convection direction. In such a usage pattern, the convection is stagnated, so that the convection effect by the heat radiating fins is not sufficiently exhibited, and the heat dissipation performance of the heat sink is reduced.

  Furthermore, since the configuration proposed in Patent Document 2 is based on the premise of forced air cooling by a cooling fan, there is a problem in that heat dissipation performance is significantly reduced when there is no cooling fan.

  The present invention has been made in view of the above problems, and an object thereof is to provide a heat sink with improved heat dissipation performance and a lighting device that can be reduced in size and weight.

  In order to achieve the above object, the invention according to claim 1 is a heat sink for cooling a heat source on the surface of a base plate having a plurality of radiating fins standing on the back surface by radiating heat by natural convection. The interval is set so as to increase from the upstream to the downstream of natural convection.

  According to a second aspect of the present invention, in the first aspect of the invention, the radiating fin is formed so as to radially spread from the center in the width direction of the upstream end of the natural convection toward the downstream of the natural convection. Features.

  According to a third aspect of the present invention, in the first or second aspect of the invention, a part of the plurality of air passages formed between the radiating fins is open in a direction substantially perpendicular to a natural convection direction. Features.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, a slit or a hole is formed in the base plate.

  A lighting device according to claim 5 is configured by mounting a light emitting element on a surface of the base plate of the heat sink according to any one of claims 1 to 4 or a substrate provided on the surface of the base plate. And

  According to the first and second aspects of the present invention, the temperature of the air that promotes the heat radiation from the radiation fins gradually increases from the upstream of the natural convection toward the downstream, and accordingly, the volume of the air also moves to the downstream side of the natural convection. Although the distance between the heat sink fins of the heat sink increases from the upstream side of the natural convection to the downstream side, the air flows smoothly along the heat sink fins and downstream of the natural convection of the air. The temperature rise toward the side is suppressed compared to the conventional one. As a result, the heat dissipation effect from the heat radiating fins is enhanced, the heat dissipation performance of the heat sink is enhanced, and the heat sink is reduced in size and weight.

  According to the third aspect of the present invention, since a part of the plurality of air passages formed between the heat radiating fins is opened in a direction substantially orthogonal to the natural convection direction, the downstream side increased by the heat radiated from the heat radiating fins. Since a part of the air escapes from the left and right sides of the heat sink in the middle and does not reach the downstream side, which is disadvantageous for heat dissipation, the temperature distribution of the heat sink in the natural convection direction is made uniform, and the heat dissipation performance of the entire heat sink is enhanced.

  According to the fourth aspect of the present invention, since the convection effect due to heat dissipation is promoted by the airflow passing through the slits or holes formed in the base plate, the heat dissipation performance of the heat sink is further enhanced, and the heat sink is further improved by the slits or holes. Can be reduced in weight.

  In addition, even when the heat sink is installed in a direction in which the base plate surface is horizontal, air passes through slits or holes formed in the base plate to promote heat dissipation from the heat radiating fins. Performance is improved than before.

  According to the invention described in claim 5, as a result of improving the heat dissipation performance of the heat sink and reducing the size and weight, the temperature rise of the light emitting element of the lighting device including the heat sink is suppressed, and the light emission efficiency of the light emitting element is reduced. The lifetime is increased, and the lighting device can be reduced in size and weight.

It is a figure which shows the LED illuminating device provided with the heat sink concerning Embodiment 1 of this invention, Comprising: (a) is a front view, (b) is a top view, (c) is the sectional view on the AA line of (a). , (D) is a sectional view taken along the line BB of (a), (e) is a side view, (f) is a sectional view taken along the line CC of (a), and (g) is a DD line of (a). Sectional drawing, (h) is a rear view, (i) is a perspective view. It is a figure which shows the LED illuminating device provided with the heat sink concerning Embodiment 2 of this invention, Comprising: (a) is a front view, (b) is a top view, (c) is the EE sectional view taken on the line of (a). , (D) is a cross-sectional view taken along line FF of (a), (e) is a side view, (f) is a cross-sectional view taken along line GG of (a), and (g) is a line H-H of (a). Sectional drawing, (h) is a rear view, (i) is a perspective view. It is a figure which shows the LED illuminating device provided with the heat sink concerning Embodiment 3 of this invention, Comprising: (a) is a front view, (b) is a top view, (c) is the II sectional view taken on the line of (a). , (D) is a sectional view taken along line JJ of (a), (e) is a side view, (f) is a sectional view taken along line KK of (a), and (g) is a line LL of (a). Sectional drawing, (h) is a rear view, (i) is a perspective view. It is a figure which shows the cooling structure of the conventional LED lighting apparatus, Comprising: (a) is a front view, (b) is a top view, (c) is the MM sectional view taken on the line (a), (d) is a side view. , (E) is a rear view, and (f) is a perspective view.

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

<Embodiment 1>
1A and 1B are diagrams showing an LED lighting apparatus according to Embodiment 1 of the present invention, in which FIG. 1A is a front view, FIG. 1B is a plan view, and FIG. 1C is a cross-sectional view taken along line AA in FIG. , (D) is a sectional view taken along the line BB of (a), (e) is a side view, (f) is a sectional view taken along the line CC of (a), and (g) is a DD line of (a). Sectional drawing, (h) is a rear view, (i) is a perspective view.

  The LED lighting device 1 according to the present embodiment includes a heat sink 10 according to the present invention as a cooling structure of an LED (light emitting diode) 2 that is a light source. Here, the heat sink 10 is made of an aluminum alloy having high thermal conductivity, and on the back surface of the base plate 11, a plurality of rectangular plate-like sheets (19 sheets in the illustrated example) that are long in the natural convection direction (vertical direction in FIG. 1). The radiating fins 12 are erected vertically with respect to the back surface of the base plate 11 at an appropriate interval in a direction substantially perpendicular to the natural convection direction (left and right direction in FIG. 1).

By the way, as shown in FIG. 1, when the LED lighting device 1 is installed so that the base plate 11 and the heat radiating fins 12 of the heat sink 10 are vertical (the light irradiation direction is the horizontal direction), it is used for heat dissipation in the heat sink 10. The air that is generated flows from the lower side to the upper side along the radiating fins 12 by natural convection. In this embodiment, the distance between the radiating fins 12 is from the upstream (lower) to the downstream (upper) of the natural convection of air. It is set to be wide. Specifically, the plurality of radiating fins 12 are formed in an arc shape so as to spread radially from the center in the width direction of the upstream end (lower end) of natural convection toward the downstream (upward) of natural convection. Here, as shown in FIG. 1 (h), when the interval between the lower ends (downstream ends) of the plurality of radiating fins 12 is A and the interval between the upper ends (upstream ends) is C,
1.5A ≦ C
The relationship is established.

  In the present embodiment, as described above, the plurality of radiating fins 12 are formed in an arc shape so as to spread radially upward from the center in the width direction of the lower end portion. A part of the air passage 13 is open toward both the left and right sides of the heat sink 10.

  Thus, in the present embodiment, the base plate 11 of the heat sink 10 has four slits 11a elongated in the horizontal direction at appropriate intervals in the vertical direction. As a result, the base plate 11 is divided into three elongated plate pieces 11A in the lateral direction by the slits 11a, and on these plate pieces 11A, a substrate on which three LEDs 2 as light sources are mounted at appropriate intervals in the lateral direction. 3 are attached, and each board | substrate 3 and three LED2 mounted in these are each covered by the outer lens 4 from the front side. Therefore, in the LED lighting device 1 according to the present embodiment, a total of nine LEDs 2 are used as light sources. In the present embodiment, each LED 2 is disposed at a position overlapping the heat dissipating fin 12 in front view. Moreover, in this Embodiment, although LED2 was used as a light source, other light emitting elements other than LED2, such as a laser diode, can be used as a light source.

  By the way, the LED illumination device 1 according to the present embodiment shows a case where the LED illumination device 1 is used for illumination in a state where it is installed so as to emit light from the LED 2 in the lateral direction. Each of the radiating fins 12 extends in the direction perpendicular to the optical axis of the LED 2 in the longitudinal direction.

  In the LED lighting device 1 configured as described above, when a total of nine LEDs 2 are energized and these LEDs 2 emit light, the light emitted from each LED 2 in the horizontal direction is transmitted through the outer lens 4 and forward (FIG. 1). The light is emitted to the front side of (a) and the left side of (e) and used for front illumination.

  Further, the heat generated by the light emission of each LED 2 is conducted from the plate piece 11A of the base plate 11 of the heat sink 10 to each heat radiating fin 12 and radiated from each heat radiating fin 12 into the air, whereby the LED 2 is cooled. At the same time, the convection effect due to heat dissipation is promoted by the airflow passing through the slit 11 a formed in the base plate 11.

  Thus, in the present embodiment, the temperature of the air that promotes the heat radiation from the heat radiation fins 12 of the heat sink 10 gradually increases from the upstream to the downstream of natural convection. Although the distance gradually increases toward the downstream side of the natural convection, the distance between the heat radiation fins 12 of the heat sink 10 is set so as to increase from the upstream (downward) to the downstream (upward) of the natural convection. 12 and the temperature rise toward the downstream side of the natural convection of air is suppressed as compared with the conventional one. As a result, the heat dissipation effect from the heat radiating fins 12 is enhanced and the heat dissipation performance of the heat sink 10 is also improved. As a result, the heat sink 10 can be reduced in size and weight. The heat sink 10 may be made of a resin having a high thermal conductivity or a metal other than an aluminum alloy.

  Further, in this embodiment, since a part of the plurality of air passages 13 formed between the heat radiating fins 12 is opened on both the left and right sides of the heat sink 10, the downstream air that has become high due to the heat radiated from the heat radiating fins 12. Is partially removed from the left and right sides of the heat sink 10 and does not reach the downstream side (upward), which is disadvantageous for heat dissipation, so that the temperature distribution of the heat sink 10 in the natural convection direction (up and down direction) is made uniform. The heat dissipation performance of the entire 10 is improved.

  Furthermore, in the present embodiment, since the convection effect due to heat dissipation is promoted by the airflow passing through the plurality of slits 11a formed in the base plate 11, the heat dissipation performance of the heat sink 10 is further enhanced, and the slit 11a improves the heat dissipation performance of the heat sink 10. Further weight reduction is achieved. Even when the heat sink 10 is installed in a direction in which the base plate 11 is horizontal, air passes through the slits 11a formed in the base plate 11 to promote heat dissipation from the heat radiating fins 12, so that the heat sink The heat dissipation performance of 10 is improved as compared with the prior art.

  As described above, the heat dissipation performance of the heat sink 10 is improved, and the size and weight are reduced. As a result, the temperature rise of the LED 2 of the LED lighting device 1 including the heat sink 10 is suppressed, and the luminous efficiency and life of the LED 2 are increased. At the same time, the LED lighting device 1 can be reduced in size and weight. And in this Embodiment, since each LED2 was arrange | positioned in the position which overlaps with the radiation fin 12 of the heat sink 10 in front view, the heat | fever from each LED2 is directly conducted to the radiation fin 12, and is dissipated from this radiation fin 12. The cooling efficiency of these LEDs 2 is increased.

  In the present embodiment, the four slits 11a are formed in the base plate 11 of the heat sink 10. However, the shape and number of the slits 11a can be arbitrarily set. In this embodiment, the slit 11a is formed in the base plate 11 of the heat sink 10. However, a hole may be formed instead of the slit 11a.

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

  2A and 2B are diagrams showing an LED lighting device according to Embodiment 2 of the present invention, in which FIG. 2A is a front view, FIG. 2B is a plan view, and FIG. 2C is a cross-sectional view taken along line EE in FIG. , (D) is a cross-sectional view taken along line FF of (a), (e) is a side view, (f) is a cross-sectional view taken along line GG of (a), and (g) is a line H-H of (a). Sectional drawing, (h) is a rear view, (i) is a perspective view. In this figure, the same elements as those shown in FIG. Is omitted.

  Also in the present embodiment, as in the first embodiment, the distance between the radiating fins 12 of the heat sink 10 is set so as to increase from the upstream (lower) to the downstream (upper) of the natural convection of air. Each radiation fin 12 is formed by bending a straight line. Also in the present embodiment, the plurality of radiating fins 12 are radially formed so as to spread from the center in the width direction of the upstream end (lower end) of natural convection toward the downstream (upward) of natural convection. Yes. A part of the plurality of air passages 13 formed between the heat radiating fins 12 is open toward both the left and right sides of the heat sink 10. Other configurations are the same as those of the first embodiment.

Here, as shown in FIG. 2 (h), the interval between the lower ends (downstream ends) of the plurality of radiating fins 12 is A, the interval between the intermediate height positions is B, and the interval between the upper ends (upstream ends) is C. Then, between these, as in the first embodiment,
1.5A ≦ C
However, a short linear radiating fin 12a as shown in the drawing may be arranged particularly at a location where the relationship of 2A ≦ B is established and the interval between the radiating fins 12 is too wide.

  Thus, also in the present embodiment, the heat generated by the light emission of each LED 2 is conducted from the base plate 11 of the heat sink 10 to the heat radiating fins 12 and 12a and radiated from the heat radiating fins 12 and 12a to the air. As described above, the LED 2 is cooled. As described above, the interval between the radiation fins 12 is set so as to increase from the upstream (downward) to the downstream (upward) of the natural air convection. Since a part of the plurality of air passages 13 formed on the left and right sides of the heat sink 10 are open to the left and right sides, the heat dissipation performance of the heat sink 10 can be improved, and the size and weight can be reduced. The effect is obtained. Further, as the heat sink 10 is reduced in size and weight, the LED lighting device 1 can be reduced in size and weight.

<Embodiment 3>
Next, a third embodiment of the present invention will be described with reference to FIG.

  FIG. 3 is a view showing an LED lighting device including a heat sink according to Embodiment 3 of the present invention, in which (a) is a front view, (b) is a plan view, and (c) is II of (a). (D) is a sectional view taken along line JJ in (a), (e) is a side view, (f) is a sectional view taken along line KK in (a), and (g) is L in (a). -L sectional view, (h) is a rear view, (i) is a perspective view, and in this figure, the same elements as those shown in FIG. The description will not be repeated.

  Also in the present embodiment, the spacing between the radiating fins 12 is set so as to increase from the upstream (downward) to the downstream (upward) of the natural convection of air, as in the first embodiment. 12 is formed in a straight line. Also in the present embodiment, the plurality of radiating fins 12 are radially formed so as to spread from the center in the width direction of the upstream end (lower end) of natural convection toward the downstream (upward) of natural convection. Yes. A part of the plurality of air passages 13 formed between the heat radiating fins 12 is open toward both the left and right sides of the heat sink 10. Other configurations are the same as those of the first and second embodiments.

Here, as shown in FIG. 3 (h), the interval between the lower ends (downstream ends) of the plurality of radiating fins 12 is A, the interval between the intermediate height positions is B, and the interval between the upper ends (upstream ends) is C. Then, between these, as in the first and second embodiments,
1.5A ≦ C
However, a short linear radiating fin 12a as shown in the figure may be disposed at a location where the relationship of 2A ≦ B is established and the interval between the radiating fins 12 is too wide.

  Thus, also in the present embodiment, the heat generated by the light emission of each LED 2 is conducted from the base plate 11 of the heat sink 10 to the heat radiating fins 12 and 12a and radiated from the heat radiating fins 12 and 12a to the air. As described above, the LED 2 is cooled. As described above, the interval between the radiation fins 12 is set so as to increase from the upstream (downward) to the downstream (upward) of the natural air convection. Since a part of the plurality of air passages 13 formed in the left and right sides of the heat sink 10 are opened, the same effect as in the first and second embodiments can be obtained.

  By the way, in the above Embodiment 1-3, although the form which applied this invention with respect to the LED illuminating device 1 which uses LED2 as a light source (heat source), and the heat sink 10 with which this was demonstrated, this invention was demonstrated. The present invention can be similarly applied to a lighting device using a light emitting element such as a laser diode other than the LED 2 as a light source and a heat sink provided therein.

  In the above embodiment, the LED 2 is mounted on the substrate 3, but a light emitting element such as the LED 2 may be directly mounted on the base plate 11 of the heat sink 10.

  The present invention can be applied to a lighting device used for light-up lighting, stadium lighting, street light lighting, road light lighting, general lighting, and the like, and a heat sink provided therein.

1 LED lighting device 2 LED (light emitting element)
3 Substrate 4 Outer lens 10 Heat sink 11 Base plate 11A Plate piece of base plate 11a Slit of base plate 12 Radiation fin 12a Radiation fin 13 Air passage

Claims (5)

In the heat sink for cooling the heat source on the surface of the base plate formed by arranging a plurality of heat radiating fins on the back by heat radiation by natural convection,
A heat sink, characterized in that the interval between the radiating fins is set so as to increase from the upstream side to the downstream side of natural convection.   2. The heat sink according to claim 1, wherein the heat dissipating fins are formed so as to spread radially from the center in the width direction of the upstream end portion of the natural convection toward the downstream of the natural convection.   3. The heat sink according to claim 1, wherein a part of the plurality of air passages formed between the heat radiating fins is opened in a direction substantially orthogonal to a natural convection direction.   The heat sink according to claim 1, wherein a slit or a hole is formed in the base plate. An illumination device comprising: a light emitting element mounted on a surface of a base plate of the heat sink according to claim 1 or a substrate provided on the surface of the base plate.

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