WO2013135841A1

WO2013135841A1 - Lighting device

Info

Publication number: WO2013135841A1
Application number: PCT/EP2013/055287
Authority: WO
Inventors: Dirk Buchhauser; Hongwei Zhang; Yuhua LIANG
Original assignee: Osram Gmbh
Priority date: 2012-03-16
Filing date: 2013-03-14
Publication date: 2013-09-19
Also published as: CN103307470B; CN103307470A

Abstract

The present invention relates to a lighting device (100) which comprises at least two LED chips (1), a heat sink (2) and a driver (3), wherein, the heat sink (2) supports the LED chips (1) at one side and has a accommodating cavity for accommodating the driver (3) at the other side, wherein the lighting device further comprises a metal heat conducting structure, which is arranged on a mounting surface (21) of the heat sink (2), and the LED chips (1) is electrically connected with the metal heat conducting structure (4) and are in thermal contact with the metal heat conducting structure (4). The lighting device according to the present invention has fine heat dissipating performance and has lowered manufacturing complexity and production cost.

Description

Description Lighting device Technical Field

The present invention relates to a lighting device. Background Art

As we all know, LED lighting has irreplaceable advantages, and it saves energy and has super low power consumption, its electro-optical power conversion efficiency is close to 100%, and it saves more than 80% of the energy compared with the traditional light sources at the same lighting efficiency and also has a long lifespan. Due to the above advantages, LED is used as a light source more and more, for example, the vast lighting devices appearing in the market. This type of light^¬ ing devices have the contour of the traditional light sources such as the incandescent lamp or lamp tube, so that it can be better applied to existing lighting systems as a light source. However, the lighting devices in the prior art have some technical problems, for example, the LED chip needs to be arranged on a printed circuit board, and a driver has to be connected with the printed circuit board via a wire so as to provide electric energy to the LED chip, which increases the manufacturing difficulty and the production cost. In ad- dition, as the heat of the LED chip needs to be delivered to the heat sink via the printed circuit board, to improve the heat conducting efficiency, a heat conducting silica gel should be coated between the printed circuit board and the heat sink, while this structure will increase the thermal re- sistance at the heat delivering path, and thus does not help radiation . Summary of the invention

To solve the above technical problems, the present invention puts forward a lighting device which LED chips are directly arranged on a heat sink, thus the traditional printed circuit board is not necessary, which leads to the fine radiating performance of the lighting device according to the present invention. In addition, the wire is not needed for the connection between the driver and the LED chips, which greatly lowers the manufacturing complexity and the production cost. The objects of the present invention are achieved via a lighting device, and the lighting device comprises: at least two LED chips, a heat sink and a driver, wherein, the heat sink supports the LED chips at one side and has a accommodat^¬ ing cavity for accommodating the driver at the other side, wherein the lighting device further comprising a metal heat conducting structure, which is arranged on a mounting surface of the heat sink, and the LED chips are electrically con^¬ nected with the metal heat conducting structure and are in thermal contact with the metal heat conducting structure. In the design solution of the present invention, the LED chips are directly fixed on the metal heat conducting structure of the heat sink, and the metal heat conducting structure also serves to conduct heat and provide electric energy to the LED chips. In addition, the metal heat conducting structure is in direct thermal contact with the mounting surface of the heat sink, then the heat from the LED chips will be directly de^¬ livered to the heat sink via the metal heat conducting struc^¬ ture, which reduces the thermal resistance at the heat deliv^¬ ering path. Preferably, the metal heat conducting structure comprises a first metal structure and a second metal structure which are concentrically disposed and circumferentially extend respec^¬ tively. Such metal structures are in direct thermal contact with the LED chips and provide electric energy to the LED chips. The electrodes of the LED chips can be electrically connected with the metal heat conducting structure directly via, for example, welding, thus the wire, for example, gold wire, is not necessary for electrical connection, which reduces manufacturing difficulty and greatly lowers the produc^¬ tion cost. As put forward in a preferable design solution according to the present invention, the driver comprises a first positive terminal and a first negative terminal, and one of the first metal structure and the second metal structure has a second positive terminal and the other of the first metal structure and the second metal structure has a second negative termi^¬ nal, the first positive terminal and the first negative ter^¬ minal and then are electrically contacted with the second positive terminal and the second negative terminal penetrat^¬ ing the mounting surface. In practical application, the posi- tive terminal and the negative terminal of the driver can be designed as pins, and the positive terminal and the negative terminal in the metal structure can be designed as slots. Electrical connection between the driver and the metal struc^¬ ture can be realized by inserting the pins into the slots, thus the wire therefore is not necessary, which further re^¬ duces the manufacturing difficulty and greatly lowers the production cost. In addition, when the driver malfunctions, the drive can be simply removed and then replaced with a new driver, then it can go on to working, which is of much prac- tical sense to general users.

Preferably, the first metal structure and the second metal structure are respectively formed as metal sheets that extend continuously in circumferential direction. Usually the metal sheets are formed as circular ones, while to meet the ar^¬ rangement of the LED chips in the lighting device, the metal sheets can also be designed in square rings, pentagon rings or hexagon rings, or etc.

In a preferable design solution of the present invention, all of the LED chips are arranged on the first metal structure or the second metal structure, wherein, one electrode of the LED chips is electrically connected with the first metal struc- ture or the second metal structure supporting the LED chips, and the other electrode of the LED chips is electrically con^¬ nected with the second metal structure or the first metal structure via a wire. Therefore, a loop is formed between the first metal structure, the LED chips, the second metal struc- ture and the driver, thereby providing electric energy for the LED chips. In addition, in this design solution, as the LED chips are all on the same metal structure, they have the maximum contact area with the metal structure, this helps ra^¬ diation much. In another preferable design solution according to the present invention, the respective LED chips respectively bridge the first metal structure and the second metal structure, wherein one electrode of the LED chips is electrically con^¬ nected with the first metal structure and the other electrode of the LED chips is electrically connected with the second metal structure. In this design solution, the first metal structure and the second metal structure are respectively in electrically contact with the two electrodes of the LED chips, thus the wire which is usually a gold wire is avoided, which helps to reduce the cost and the lower the manufactur^¬ ing complexity. According to still another preferable design solution of the present invention, the first metal structure and the second metal structure respectively comprise a plurality of metal sheet segments insulated from each other. Preferably, one of the metal sheet segments of the first metal structure is electrically connected with one of the metal sheet segments of the second metal structure via the wire. Advantageously, a part of the LED chips respectively bridges adjacent metal sheet segments of the first metal structure, and the other part of the LED chips bridge adjacent metal sheet segments of the second metal structure. In this design solution, the re^¬ spective LED chips respectively bridge two adjacent metal sheet segments of the same metal structure, thereby forming series connection between the LED chips on the same metal structure. At the same time, the first metal structure and the second metal structure are electrically connected there^¬ between via a wire, thus a loop is formed between the LED chips, the first metal structure, the second metal structure and the driver. Preferably, the heat sink comprises body and a plurality of fins radially arranged on the outer surface of a body, which prominently increases the contact area of the heat sink with the ambient environment and improves the radiation effect of the heat sink. Further preferably, the heat sink further comprises a plural^¬ ity of auxiliary metal fins which are encapsulated in the fins. The auxiliary metal fins have a high thermal conductiv^¬ ity which helps improve the heat dissipating performance of the heat sink. Advantageously, the auxiliary metal fin are respectively en^¬ capsulated in the fins through an insert molding process ,

b

through which the auxiliary metal fin can be in seamless contact with the fins, thus effectively reducing the thermal re^¬ sistance at the heat delivering path.

Preferably, the first metal structure or the second metal structure is in direct thermal contact with the auxiliary metal fin. The heat from the LED chips is directly delivered to the auxiliary metal fin through the metal structures in thermal contact with the LED chips, thereby improving the heat dissipating performance of the heat sink. As put forward in a preferable design solution according to the present invention, the body and the fins are made of an electrically insulating thermal conductive plastic through and are integrally formed through an insert molding process. The thermal conductive plastic has fine plasticity and can be used to make various shapes of heat sinks according to needs at low costs. Meanwhile, the electrically insulating thermal conductive plastic has fine electrical insulating perform^¬ ance, thus it is unnecessary to preserve a large space during designing the heat sink considering the necessary creepage distance between the driver and the heat sink, which reduces the space of the heat sink. In addition, the drive need not be arranged in a dedicated driver housing and can be directly arranged the receiving space of the heat sink.

Preferably, the first metal structure, the second metal structure and the auxiliary metal fin are made of a copper- based or aluminum-based material. The heat sink of the light^¬ ing device according to the present invention is a mixing- type heat sink and has advantages of both fine heat dissipat^¬ ing performance and small structural weight. 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 de^¬ scribe the principles of the present invention together with the Description. In the accompanying drawings the same compo^¬ nents are represented by the same reference numbers. As shown in the drawings : Fig. 1 is an exploded perspective view of the first embodi^¬ ment of the lighting device according to the present inven^¬ tion;

Figure 2 is an exploded perspective view of the second em^¬ bodiment of the lighting device according to the present in- vention; and

Figure 3 is an exploded perspective view of the third embodi^¬ ment of the lighting device according to the present inven^¬ tion.

Detailed Description of the Embodiments Fig. 1 illustrates the exploded perspective view of the first embodiment of the lighting device 100 according to the pre^¬ sent invention. Seen from the figure, lighting device 100 ac^¬ cording to the present invention comprises at least two LED chips 1, a heat sink 2 and a driver 3, wherein, the heat sink 2 supports the LED chips 1 at one side and has an accommodat^¬ ing cavity for accommodating the driver 3 at the other side, the heat sink 2 has a mounting surface 21 at the side for supporting the LED chips 1, a metal heat conducting structure 4 is arranged on the mounting surface 21, and the LED chips 1 are electrically connected with the metal heat conducting structure 4 and is in thermal contact with the metal heat conducting structure 4. Seen from the figure, the metal heat conducting structure 4 comprises a first metal structure 41 and a second metal structure 42 that are concentrically arranged on the mounting surface lb and circumferentially extend respectively. Further seen from the figure, the first metal structure 41 and the second metal structure 42 are respectively formed as metal sheets that extend continuously in circumferential direction. In this embodiment, the metal sheets are formed as circular ones, while to meet the arrangement of the LED chips 1 in the lighting device 100, the metal sheets can also be designed in square rings, pentagon rings or hexagon rings, or etc.

The structure of the driver 3 can also be seen from Figure 1, and in the design solution of the present invention, the driver 3 comprises a first positive terminal 31 and a first negative terminal 32, a second positive terminal 411 is pro- vided on the first metal structure 41 and a second negative terminal 421 is provided on the second metal structure 42, the first positive terminal 31 and the first negative termi^¬ nal 32 respectively penetrate the mounting surface 21 and then are electrically contacted with the corresponding second positive terminal 411 and the second negative terminal 421. In the embodiments of the present invention, the first posi^¬ tive terminal 31 and the first negative terminal 32 of the driver 3 can be formed as pins, and the second positive ter^¬ minal 411 and the second negative terminal 421 in the first metal structure 41 and the second metal structure 42 can be formed as slots. Electrical connection between the driver 3 and the first metal structure 41 and the second metal struc- ture 42 can be realized by inserting the pins into the slots, thus the wire therefore is not necessary, which further re^¬ duces the manufacturing difficulty and greatly lowers the production cost. The heat sink 1 comprises body 22 and a plurality of fins 23 radially arranged on the outer surface of a body 22 and a plurality of auxiliary metal fins 24, and such auxiliary metal fin 24 are encapsulated in the fins 23 through an in^¬ sert molding process. In addition, to ensure fine heat dissi- pating performance, the body 22 and the fins 23 are inte^¬ grally formed of an electrically insulating thermal conduc^¬ tive plastic through an insert molding process. The first metal structure 41, the second metal structure 42 and the auxiliary metal fin 24 are formed of a copper-based or alumi- num-based material, thereby obtaining a mixing-type heat sink. To further improve the radiating performance of the heat sink 2, the first metal structure 41 or the second metal structure 42 is in direct thermal contact with the auxiliary metal fin. Heat from the LED chips 1 is directly delivered to the auxiliary metal fin 24 via the metal structure in thermal contact with the LED chips, thereby improving the radiating performance of the heat sink 2.

In the first embodiment of the present invention, all the LED chips 1 are arranged on the first metal structure 41, and certainly all the LED chips 1 can be arranged on the second metal structure 42. One electrode of the LED chips 1 is elec^¬ trically connected with the first metal structure 41, and the other electrode of the LED chips 1 is electrically connected with the second metal structure 42 via a wire 5, for example, a gold wire. Therefore, a loop is formed between the first metal structure 41, the LED chips 1, the second metal struc^¬ ture 42 and the driver 3, thereby providing electric energy for the LED chips 1. In addition, in this design solution, as the LED chips 1 are all on the same metal structure, they have the maximum contact area with the metal structure, this helps radiation much. Figure 2 illustrates an exploded perspective view of the sec^¬ ond embodiment of the lighting device 100 according to the present invention. The second embodiment of the lighting de^¬ vice 100 according to the present invention is different from the first embodiment in the regard of arrangement of the LED chips 1 on the metal heat conducting structure 4. In the sec^¬ ond embodiment of the lighting device according to the pre^¬ sent invention, the respective LED chips 1 respectively bridge the first metal structure 41 and the second metal structure 42, wherein one electrode of the LED chips 1 is electrically connected with the first metal structure 41, and the other electrode of the LED chips 1 is electrically con^¬ nected with the second metal structure 42. In this embodi^¬ ment, the first metal structure 41 and the second metal structure 42 are respectively in electrically contact with the two electrodes of the LED chips 1, thus the use of the wire is avoided, which reduces cost and lowers manufacturing complexity .

Figure 3 illustrates an exploded perspective view of the third embodiment of the lighting device 100 according to the present invention, which differs from the above two embodi^¬ ments in the regards of the arrangement of the LED chips 1 on the metal heat conducting structure 4 and the structure of the metal heat conducting structure 4. Seen from Figure 3, the first metal structure 41 and the second metal structure 42 respectively comprise a plurality of metal sheet segments insulated from each other, and one of the metal sheet seg^¬ ments of the first metal structure 41 is electrically con- nected with one of the metal sheet segments of the second metal structure 42 via the wire 5. A part of the LED chips 1 respectively bridges adjacent metal sheet segments of the first metal structure 41, and the other part of the LED chips 1 are respectively bridge adjacent metal sheet segments of the second metal structure 42. In this embodiment, the re^¬ spective LED chips 1 respectively bridge two adjacent metal sheet segments of the same metal structure, thereby forming series connection between the LED chips 1 on the same metal structure. At the same time, the first metal structure 41 and the second metal structure 42 are electrically connected via a wire 5, thus a loop is formed between the LED chips 1, the first metal structure 41, the second metal structure 42 and the driver 3. The above is merely preferred embodiments of the present in^¬ vention but not to limit the present invention. For the per^¬ son skilled in the art, the present invention may have vari^¬ ous alterations and changes. Any alterations, equivalent sub^¬ stitutions, improvements, within the spirit and principle of the present invention, should be covered in the protection scope of the present invention.

List of reference signs

1 LED chip

2 heat sink

21 mounting surface

22 body

23 fin

24 auxiliary metal radiating sheet

3 driver

31 first positive terminal

32 first negative terminal

4 metal heat conducting structure

41 first metal structure

411 second positive terminal

42 second metal structure

421 second negative terminal

5 wire

100 lighting device

Claims

1. A lighting device (100), comprising at least two LED chips (1), a heat sink (2) and a driver (3), wherein, the heat sink (2) supports the LED chips (1) at one side and has a accommodating cavity for accommodating the driver (3) at the other side, characterized in that further comprising a metal heat conducting structure, which is arranged on a mounting surface (21) of the heat sink (2), and the LED chips (1) are electrically connected with the metal heat conducting structure (4) and is in thermal contact with the metal heat conducting structure (4).

2. The lighting device (100) according to claim 1, characterized in that the metal heat conducting structure (4) com- prises a first metal structure (41) and a second metal struc^¬ ture (42) that are concentrically disposed and circumferen- tially extend respectively.

3. The lighting device (100) according to claim 2, charac^¬ terized in that the driver (3) comprises a first positive terminal (31) and a first negative terminal (32), and one of the first metal structure (41) and the second metal structure (42) has a second positive terminal (411) and the other of the first metal structure (41) and the second metal structure (42) has a second negative terminal (421), the first positive terminal (31) and the first negative terminal (32)mounting surface are electrically contacted with the second positive terminal (411) and the second negative terminal (421) pene^¬ trating the mounting surface (21) .

4. The lighting device (100) according to claim 3, charac- terized in that the first metal structure (41) and the second metal structure (42) are respectively formed as metal sheets that extend continuously in circumferential direction.

5. The lighting device (100) according to claim 4, charac^¬ terized in that all of the LED chips (1) are arranged on the first metal structure (41) or the second metal structure (42), one electrode of the LED chips (1) is electrically con^¬ nected with the first metal structure (41) or the second metal structure (42) supporting the LED chips (1), and the other electrode of the LED chips (1) is electrically con^¬ nected with the second metal structure (42) or the first metal structure (41) via a wire (5) .

6. The lighting device (100) according to claim 4, charac^¬ terized in that the respective LED chips (1) respectively bridge the first metal structure (41) and the second metal structure (42), wherein one electrode of the LED chips (1) is electrically connected with the first metal structure (41) and the other electrode of the LED chips (1) are electrically connected with the second metal structure (42) .

7. The lighting device (100) according to claim 3, charac^¬ terized in that the first metal structure (41) and the second metal structure (42) respectively comprise a plurality of metal sheet segments insulated from each other.

8. The lighting device (100) according to claim 7, charac^¬ terized in that one of the metal sheet segments of the first metal structure (41) is electrically connected with one of the metal sheet segments of the second metal structure (42) via the wire (5) .

9. The lighting device (100) according to claim 8, charac^¬ terized in that a part of the LED chips (1) respectively bridge adjacent metal sheet segments of the first metal structure (41), and the other part of the LED chips (1) re^¬ spectively bridges adjacent metal sheet segments of the sec^¬ ond metal structure (42) .

10. The lighting device (100) according to any of claims 2 to 8, characterized in that the heat sink (2) comprises body (22) and a plurality of fins (23) radially arranged on the outer surface of a body (22) .

11. The lighting device (100) according to claim 10, charac^¬ terized in that the heat sink (2) further comprises a plural- ity of auxiliary metal fin (24) which are encapsulated in the fins (23) .

12. The lighting device (100) according to claim 10, charac^¬ terized in that the auxiliary metal fin (24) are respectively encapsulated in the fins (23) through an insert molding proc- ess .

13. The lighting device (100) according to any of claims 2 to 8, characterized in that the first metal structure (41) or the second metal structure (42) is in direct thermal contact with the auxiliary metal fin (24) .

14. The lighting device (100) according to claim 10, charac^¬ terized in that the body (22) and the fins (23) are made of an electrically insulating thermal conductive plastic and in^¬ tegrally formed by an insert molding process.

15. The lighting device (100) according to claim 11, charac- terized in that the first metal structure (41), the second metal structure (42) and the auxiliary metal fin (24) are made of a copper-based or aluminum-based material.