EP2802804B1

EP2802804B1 - Heat dissipation device, lighting device, and luminaire having said lighting device

Info

Publication number: EP2802804B1
Application number: EP13700025.3A
Authority: EP
Inventors: Hongwei Zhang; Xiaoyu Chen; Jin Hu; Qihui Zhang
Original assignee: Osram GmbH
Current assignee: Osram GmbH
Priority date: 2012-01-11
Filing date: 2013-01-03
Publication date: 2016-08-24
Anticipated expiration: 2033-01-03
Also published as: CN103206689A; WO2013104553A1; EP2802804A1; CN103206689B

Description

Technical Field

The present invention relates to a heat dissipation device, a lighting device, and a luminaire having said lighting device.

Background Art

Lighting device generally have a large demand for heat dissipation since a light engine and a driver are both heat sources generating a large amount of heat. Thus, efficient heat dissipation is required to ensure the normal operation of the lighting device. Especially for an LED lighting device, the above demand becomes more urgent.
US patent application 2008101065 describes a backlight module including a light box, a plurality of light source sets, and a heat dissipation device is provided. The light box has a bottom and a light-emitting section. The heat dissipation device includes a thermal assembly and at least one fan, and the thermal assembly includes a plurality of covers. An air flow channel is formed between each cover and the bottom.
US patent application 2012037926 describes a solid state lighting (SSL) with a solid state emitter (SSE) having thermally conductive projections extending into an air channel. The air channel can be oriented generally vertically such that air in the channel warmed by the SSE flows upward through the channel.
DE 102007045555 A1 also discloses a heat dissipation device with a plurality of heat pipes arranged in the vent holes. However, the vent holes are not opened in the base wall. Furthermore, one end of the heat pipes protrude from vent holes, so not in air communication with the vent holes. The structure of the heat dissipation device is therefore rather complicated to accommodate the heat pipes.
A typical LED lighting device comprises a light engine, a heat dissipation device, and a driver. The heat dissipation device is provided between the light engine and the driver. The heat dissipation device is in direct thermal contact with the light engine and the driver. By means of the thermal contact portion of the heat dissipation device, the heat generated is transferred to other parts of the heat dissipation device for heat dissipation. However, due to the limited contact area of the direct thermal contact portion and the limited heat dissipation capacities, the overall heat dissipation capacities of the heat dissipation device will be limited.
In the prior art there are several solutions as follows:

The first solution in the prior art is potting a heat dissipation gel, viz. potting the heat dissipation gel into the cavity of the heat dissipation device accommodating the light engine or accommodating the driver to improve the heat dissipation capacities. However, the drawback of this solution lies in increasing the cost and the weight of the whole lighting device.

The second solution in the prior art is providing a thickened base wall and using the same to support the light engine so as to enhance the heat dissipation capacities of the contact portion. However, the drawback of this solution lies in increasing the cost and the weight of the whole lighting device.
The third solution in the prior art is reducing the light output so as to reduce the generated heat. However, this solution obviously is contrary to the client's demand for high light output.
Therefore, it is an urgent need to provide a heat dissipation device having high heat dissipation capacity, especially a heat dissipation device for a lighting device.

Summary of the Invention

Therefore, the object of the present invention lies in providing a heat dissipation device which is capable of overcoming the drawbacks of various solutions in the prior art and has the advantages of having a simple manufacturing process and remarkably improving the heat dissipation capacities.
According to the present invention there is provided a heat dissipation device, characterized by, comprising a heat dissipation body and a plurality of heat dissipation pipes , wherein the heat dissipation body has heat dissipation wall which defined an accommodating cavity for at least partially accommodating a first heat source, the heat dissipation wall have a plurality of vent holes, the heat dissipation pipes are mounted into the accommodating cavity through the vent holes, and one end of the heat dissipation pipe is in air communication with the vent hole. The plurality of heat dissipation pipes are arranged in such a way that the heat dissipation pipes are in contact with walls defining the vent holes. The combination of the first vent holes and the heat dissipation pipes not only increases the thermal conduction area and the air convection around the first heat source, but also reduces the overall thermal resistance of the heat dissipation device, thereby remarkably improving the heat dissipation capacity. According to one preferred solution of the present invention, the heat dissipation wall has a base wall and a circumferential wall which defined the accommodating cavity jointly with the base wall, and first vent holes are opened in the base wall. In said solution, the heat dissipation body may be configured to have, for example, an inverted U shape or have an closed accommodating cavity. In these two cases, the bottom surface of the accommodating cavity may be configured as the base wall having the first vent holes so as to dissipate heat in the accommodating cavity where a second heat source is located, to the outside.
Preferably, the base wall has a support portion supporting a second heat source and a circumferential area enclosing the support portion, the first vent holes being opened in the circumferential area. Hence, in the presence of the first heat source and the second heat source, the effect of the heat dissipation path of the first heat source on that of the second heat source may be reduced as much as possible. Preferably, accommodating cavity is a cavity opened at one side. In the case of the open accommodating cavity, the possibility is provided that the first heat source partially protrudes out of the accommodating cavity, thereby further improving the heat dissipation of the first heat source. According to one preferred solution of the present invention, the circumferential wall has a first section and a second section, the first section and the second section define a surface of the heat dissipation body facing away from the base wall, a plurality of second vent holes are opened in the surface, and the other end of the heat dissipation pipe is in air communication with the second vent hole. The plurality of heat dissipation pipes are arranged in such a way that the heat dissipation pipes are in contact with walls defining the second vent holes. The first vent holes are in air communication with the second vent holes via the heat dissipation pipes, thereby further improving the heat dissipation capacity.
Preferably, the first section has a conical shape and the second section has a cylindrical shape. Thus, it is possible not only to provide the second vent holes, but also to matches with the shape second heat source. In addition, the overall appearance of the heat dissipation device can be improved.
Preferably, the plurality of first vent holes and the plurality of second vent holes are circumferentially distributed on the base wall and the surface, respectively, such that the heat generated in the respective directions may be dissipated outward.
Preferably, the heat dissipation pipes are made of copper. Due to the good heat conduction performance of the copper, the heat dissipation capacity of the heat dissipation device may be further improved.
Preferably, the heat dissipation body is made of Al. Since Al as a light metal has the advantages of good heat dissipation performance and lighter weight, a balance may be achieved between the heat dissipation performance and the weight of the whole heat dissipation device.
Preferably, the heat dissipation body is formed by a spinning or punching process. The use of said process makes it easy to form the heat dissipation body and the vent holes of the heat dissipation body and reduces significantly the manufacturing cost.
The present invention also relates to a lighting device comprising the heat dissipation device as described above, a driver housing for accommodating a driver as a first heat source and a light engine as a second heat source. The heat dissipation manner of combining the above heat dissipation pipes and the first vent holes of the heat dissipation device according to the present invention increases the overall structure strength and separates the heat of the driver from the heat of the light engine, thereby improving the heat dissipation capacities of the lighting device.
Preferably, the light engine comprises a circuit board and an LED chip provided on the circuit board. The heat dissipation device according to the present invention particularly satisfies the high requirement for heat dissipation of the LED chip.
Preferably, the lighting device further comprises a housing which encloses the light engine and is mounted to the support portion of the base wall, with the first vent holes exposed. The first vent holes are exposed directly to the ambient surroundings, which may transfer heat directly to the ambient surroundings and further reduce the effect of the light engine on the heat dissipation.
Preferably, the driver housing has a cylindrical portion at a side facing the accommodating cavity and a collar at a side facing away from the accommodating cavity, the collar protruding out of the accommodating cavity. The collar at least partially protrudes out of the accommodating cavity, which ensures that part of heat may be dissipated from one side of the driver housing and that the heat may be dissipated via the second vent holes from one side of the driver housing.
Preferably, the plurality of heat dissipation pipes are mounted in the accommodating cavity, in an area between the heat dissipation device and the driver housing, and are in communication with the first vent holes and the second vent holes. Thus, the heat of the driver may be dissipated outward from either the first vent holes or the second vent holes.
Preferably, the plurality of heat dissipation pipes are arranged in such a way that the heat dissipation pipes are in contact with walls defining the first vent holes and the second vent holes, thereby improving not only the heat dissipation by air convection but also the heat dissipation by conduction.
The present invention further relates to a luminaire. The lighting device and the luminaire according to the present invention have the advantages of having a simple manufacturing process and low cost as well as remarkably improving the heat dissipation capacities.
It should be understood that the general descriptions above and detailed descriptions below are only illustrative for the purpose of further explaining the present invention required.

Brief Description of the Drawings

The accompanying drawings constitute a part of the present Description and are used to provide further understanding of the present invention. Such accompanying drawings illustrate the embodiments of the present invention and are used to describe the principles of the present invention together with the Description. In the accompanying drawings the same components are represented by the same reference numbers. As shown in the drawings:

Fig. 1 is a stereoscopic view of a lighting device according to a first embodiment according to the present invention;
Fig. 2 is an exploded view of a lighting device according to a first embodiment according to the present invention;
Fig. 3 is a side sectional view of a lighting device according to a first embodiment according to the present invention;
Fig. 4 is a top view of a lighting device according to a first embodiment of the present invention;
Fig. 5 is a front view of a lighting device according to a first embodiment of the present invention; and
Fig. 6 is a bottom view of a lighting device according to a first embodiment of the present invention.

Detailed Description of the Embodiments

Fig. 1 is a stereoscopic view of a lighting device 100 according to a first embodiment according to the present invention. Fig. 2 is an exploded view of a lighting device 100 according to a first embodiment according to the present invention. Fig. 2 shows a heat dissipation device 10 according to the present invention. The heat dissipation device 10 according to the present invention mainly comprises two parts: a heat dissipation body 1 and a plurality of heat dissipation pipes 2. Vent holes are opened in the heat dissipation body 1, for example, first vent holes 14 as shown in this embodiment. The heat dissipation pipes 2 may be made of high thermal conduction materials and are configured to be inserted into the first vent holes 14 of the heat dissipation body 1 and further inserted into an accommodating cavity 15 (see Fig. 3) of the heat dissipation body 1 for accommodating a first heat source. Since the heat dissipation pipes 2 not only are in contact with the heat dissipation body 1 to increase the heat dissipation area for transferring the heat in the accommodating cavity 15 but also form an air convection path with the first vent holes, the heat dissipation capacities are significantly improved.
The heat dissipation body 1 comprises a base wall 13 as a bottom surface and a circumferential wall 16 defining the accommodating cavity 15 together with the base wall 13. The first vent holes 14 are opened in the base wall 13. Specifically, said base wall 13 comprises two parts, viz. a support portion 131 which is mainly used for supporting and being in thermal contact with a second heat source 4 and a circumferential area 132 which is arranged to surround the support portion 131. The first vent holes 14 are opened in the circumferential area 132 in said preferred embodiment to separate heat dissipation paths of a first heat source 3 and the second heat source 4. The first vent holes 14 are preferably uniformly distributed in the circumferential area 132 to realize uniform and comprehensive heat dissipation.
Besides the first vent holes 14, second vent holes 18 may further be provided. The second vent holes 18 are preferably opened at the position of the heat dissipation body 1 facing away from the first vent holes 14. In said specific embodiment, the accommodating cavity 15 is open at the first heat source side. At an open end a surface 17 is formed on which the second vent holes 18 are opened and which are used for supporting the heat dissipation pipes 2. Specifically, the circumferential wall 16 has a first section 161 and a second section 162. The second section has a smaller diameter than the first section, thereby forming a step, which is the end surface 17 of the heat dissipation body 1 facing away from the base wall 13. A plurality of second vent holes 18 are opened in the end surface 17. The other end 22 of the heat dissipation pipe 2 is in air communication with the second vent hole 18. Thus, the heat may be dissipated either from the second heat source side or from the first heat source side. Likewise, the second vent holes 18 (see Fig. 3) are preferably uniformly distributed on the surface 17 so as to realize uniform and comprehensive heat dissipation.
The lighting device comprising an improved heat dissipation device according to the present invention is as shown in Figs. 1 and 2. As may be seen with reference to Fig. 1 and Fig. 2, the lighting device 100 comprises a housing 5, a light engine 4, the heat dissipation device 10, a driver housing 3 for accommodating a driver (not shown), and an electrical connection part 6 connected to a power supply. The light engine 4 comprises a circuit board and an LED chip provided on the circuit board. The housing 5 is mounted to the heat dissipation device 10 so as to adjust the direction of light emitted from the LED chip 42 of the light engine 4 supported by the support portion 131 of the base wall 3 of the heat dissipation device 10. The shape of the housing 5 is designed to match the profile of the heat dissipation device 10. The two jointly form a streamlined profile, especially jointly forming a profile similar to a conventional incandescent lamp. The driver housing 3 partially protrudes from the heat dissipation device 10 and a protruding portion 32 also matches the profile of the heat dissipation device 10 to jointly constitute a streamlined profile, ensuring that the lighting device 100 is configured to have a compact structure and an artistic appearance. The driver housing 3 is electrically connected to the light engine 4 via the heat dissipation device 10 at one side and electrically connected to the electrical connection part 6 leading to the power supply at the other side. Since the present invention does not focus on the electrical connection, a detailed description of how to perform the electrical connection is omitted herein.
The heat dissipation device 10 according to the present invention is provided between the light engine 4 and the driver housing 3. The light engine 4 and the driver housing 3 are mounted at two sides of the heat dissipation device 10, respectively. The light engine 4 is mounted at a first side 11 of the heat dissipation device 10 viz. an upper surface as shown in said figure, and the driver housing 3 accommodating the driver mounted at the other side 12, viz. a lower surface as shown in said figure. According to the present invention, the heat dissipation body 1 supports the light engine 4 at one side, and the heat dissipation device 10 may have a cavity formed at one side for accommodating the light engine 4 or may have the base wall 13 of the heat dissipation body 1 for supporting the light engine 4, as shown in said embodiment. The heat dissipation body 1 has the accommodating cavity 15 for at least partially accommodating the driver housing 3 formed at the other side, said accommodating cavity 15 being defined by the base wall 13 and the circumferential wall 16. The heat dissipation body 1 of the heat dissipation device 10 has the first vent holes 14 and/or the second vent holes 18. The first vent holes 14 are in air communication with the second vent holes 18 or in air communication with the second vent holes 18 preferably via the heat dissipation pipes 2 (see Fig. 3). As shown in Fig. 1, the first vent holes 14 are exposed and in direct communication with the ambient surroundings. As shown in Fig. 3, the second vent holes 18 are exposed and in direct communication with the ambient surroundings.
Fig. 3 is a side sectional view of a lighting device according to a first embodiment according to the present invention. As shown in Fig. 3, the plurality of heat dissipation pipes 2 are provided in an area of the accommodating cavity 15 between the heat dissipation device 10 and the driver housing 3. These heat dissipation pipes uniformly surround the driver housing 3 in a circumferential direction to receive the heat of the driver housing 3 uniformly and comprehensively. The heat dissipation pipes 2 are not only in communication with the first vent holes 14 and the second vent holes 18 but also in direct thermal contact with walls defining the first vent holes 14 and the second vent holes 18 so as to realize a combination of two heat dissipation manners, thermal conduction and air convection. The lighting device 100 according to the present invention improves the effect of heat dissipation by air convection and prevents the heat of the driver from being transferred to the light engine 4.
In said embodiment, the driver housing 3 has a cylindrical portion 31 and a collar 32. The cylindrical portion 31 is configured to be just accommodated in the accommodating cavity 15. The collar 32 has a larger size than the cylindrical portion 31 and is configured to protrude from the heat dissipation device 10 and constitute a part of the profile of the lighting device 100. The shape of the driver housing may be freely designed according to different design requirements. According to said embodiment, the driver housing 3 is made of plastic and manufactured by an injection molding process. Therefore, plastic with general heat dissipation capacity such as PC, PE, and so on is generally used to make the driver housing, thereby reducing the cost and the processing complexity. The selection of the heat dissipation materials for the heat dissipation body and the heat dissipation pipes shall be made in consideration of a balance between the improvement of the overall heat dissipation capacity and the total weight of the heat dissipation device. Preferably, the heat dissipation body is made of Al with better heat dissipation capacity and lighter weight and the heat dissipation pipes are made of copper. In other embodiment, other heat dissipation metal may be selected. The heat dissipation device 10 may be formed by a spinning or punching process or by other low-cost processes.
Fig. 4 is a top view of a lighting device according to a first embodiment of the present invention, Fig. 5 is a front view of a lighting device according to a first embodiment of the present invention, and Fig. 6 is a bottom view of a lighting device according to a first embodiment of the present invention. With reference to Fig. 4 to Fig. 6, the details of the lighting device 100 may be seen more clearly. It is shown in the figures that the first vent holes 14 and the second vent holes 18 may effectively dissipate the heat transferred by the heat dissipation pipes 2 to the ambient surroundings, thereby improving the heat dissipation capacity of the lighting device of the present invention.
The above is merely preferred embodiments of the present invention but not to limit the present invention. For the person skilled in the art, the present invention may have various alterations and changes.

List of reference signs

100: lighting device
10: heat dissipation device
1: heat dissipation body
2: heat dissipation pipes
3: driver housing
4: light engine
5: housing
6: electrical connection part
11: first side
12: second side
13: base wall
14: first vent holes
15: accommodating cavity
16: circumferential wall
17: surface
18: second vent holes
21: one end
22: the other end
131: support portion
132: circumferential area
161: first section
162: second section
31: cylindrical portion
32: collar
41: circuit board
42: LED chip

Claims

A heat dissipation device (10) comprising a heat dissipation body (1) and a plurality of heat dissipation pipes (2), wherein the heat dissipation body (1) has a heat dissipation wall which defined an accommodating cavity (15) for at least partially accommodating a first heat source, the heat dissipation wall has a plurality of vent holes, the heat dissipation pipes (2) are mounted into the accommodating cavity (15) through the vent holes, and one end (21) of the heat dissipation pipe (2) is in air communication with the vent hole, wherein the plurality of heat dissipation pipes (2) are arranged in such a way that the heat dissipation pipes (2) are in contact with walls defining the vent holes, characterized in that the heat dissipation wall has a base wall (13) and a circumferential wall which defined the accommodating cavity jointly with the base wall (13), and first vent holes (14) are opened in the base wall (13).
The heat dissipation device (10) according to Claim 1, characterized in that, the base wall (13) has a support portion (131) supporting a second heat source and a circumferential area (132) enclosing the support portion (131), and the first vent holes (14) being opened in the circumferential area (132).
The heat dissipation device (10) according to any one of Claims 1 to 2, characterized in that, accommodating cavity (15) is a cavity opened at one side.
The heat dissipation device (10) according to Claim 3, characterized in that, the circumferential wall (16) has a first section (161) and a second section (162), the first section (161) and the second section (162) define an end surface (17) of the heat dissipation body (1) facing away from the base wall (13), a plurality of second vent holes (18) are opened in the end surface (17), and the other end (22) of the heat dissipation pipe (2) is in air communication with the second vent hole (18), wherein the plurality of heat dissipation pipes are arranged in such a way that the heat dissipation pipes (2) are in contact with walls defining the second vent holes (18).
The heat dissipation device (10) according to Claim 4, characterized in that, the first section (161) has a conical shape and the second section (162) has a cylindrical shape.
The heat dissipation device (10) according to Claim 3, characterized in that, the plurality of first vent holes (14) and the plurality of second vent holes (18) are circumferentially distributed on the base wall (13) and the end surface (17), respectively.
The heat dissipation device (10) according to any one of Claims 1 to 2, characterized in that, the heat dissipation pipes (2) are made of copper.
The heat dissipation device (10) according to any one of Claims 1 to 2, characterized in that, the heat dissipation body (1) is made of Al.
The heat dissipation device (10) according to Claim 8, characterized in that, the heat dissipation body (1) is formed by a spinning or punching process.
A lighting device (100), comprises the heat dissipation device (10) according to any one of Claims 1 to 9, a driver housing for accommodating a driver as a first heat source and a light engine as a second heat source.
The lighting device (100) according to Claim 10, characterized in that, the light engine comprises a circuit board (41) and an LED chip (42) provided on the circuit board (41).
The lighting device (100) according to Claim 10, characterized in that, the lighting device further comprises a housing (5) which encloses the light engine and is mounted to the support portion (131) of the base wall (13) with the first vent holes (14) exposed.
The lighting device (100) according to Claim 10, characterized in that, the driver housing has a cylindrical portion (31) at a side facing to the accommodating cavity (15) and a collar (32) at a side facing away from the accommodating cavity (15), and the collar (32) protrudes from the accommodating cavity.
The lighting device (100) according to Claim 10, characterized in that, the plurality of heat dissipation pipes (2) are mounted in the accommodating cavity (15), in an area between the heat dissipation device (10) and the driver housing (3), which are in communication with the first vent holes (14) and the second vent holes (18).
A luminaire, comprising the lighting device (100) according to any one of Claims 1 to 14.
The luminaire according to Claim 15, wherein the luminair is a retrofit lamp.