EP2783153B1 - Cooling body for semiconductor lighting device with plastics parts - Google Patents

Description

The invention relates to a heat sink for a semiconductor light-emitting device, wherein the heat sink has a first plastic part, which has a rear-side receiving space, and a second plastic part, which is connected to the first plastic part at the front side and is provided for arranging at least one semiconductor light source the first plastic part has a lower thermal conductivity than the second plastic part. The invention further relates to a semiconductor luminescent device with such a heat sink. The invention can be used particularly advantageously for retrofit lamps.

DE 10 2010 030 702 A1 discloses a semiconductor lamp having a driver cavity for receiving driver electronics and a light source substrate equipped with at least one semiconductor light source. The light source substrate closes the driver cavity. The housing parts of the semiconductor lamp are constructed as heat sinks with different thermal conductivities.

DE 10 2009 024 904 A1 discloses a heat sink for cooling a semiconductor light-emitting element. The heat sink has a mounting recess for partially receiving a control electronics. The heat sink is composed of several heat sink parts.

DE 10 2009 022 071 A1 discloses a heat sink for a lighting device composed of a plurality of heat sink parts, wherein at least two of the heat sink parts are made of a different heat sink material. The lighting device, which can be configured in particular as a retrofit lamp, is equipped with at least one such heat sink. At least one light source may be attached to at least a first heat sink portion of a first heat sink material, and at least one second heat sink portion of a second heat sink material may not have a light source attached thereto. The second heat sink material may have a lower thermal conductivity than the first heat sink material.

It is the object of the present invention to provide an improved, in particular easy to manufacture and more effective, heat sink for semiconductor light devices.

This object is achieved according to the features of the independent claims. Preferred embodiments are in particular the dependent claims.

The object is achieved by a heat sink for a semiconductor luminescent device, wherein the heat sink has a first plastic part, which has a receiving space open at the rear, and a second plastic part, which is connected to the first plastic part at the front side and is provided for arranging at least one semiconductor light source wherein the first plastic part has a lower thermal conductivity than the second plastic part and in the heat sink at least one insert is present, which has a higher thermal conductivity than the second plastic part.

This heat sink has the advantage that due to the lower thermal conductivity of the first plastic part, an object located in the receiving space is thermally insulated from the at least one semiconductor light source. This can be particularly advantageous when the at least one semiconductor light source generates waste heat to a considerable extent and the article is sensitive to heat, in particular if the article itself is electrically operable and generates waste heat. In addition, an at least largely made of plastic heat sink can be particularly easy and inexpensive and easy to manufacture.

By means of the insert, a heat spread in and heat removal from the plastic of one of the plastic parts or both plastic parts can be improved, in particular into or out of the thermally less conductive first plastic part. This in particular improves heat removal from the receiving space and prevents overheating of an object accommodated in the receiving space.

The at least one insert may comprise (exactly) one or more inserts.

The first plastic part may in particular have a thermal conductivity of not more than 1 W / (m · K), in particular not more than 0.6 W / (m · K). The second plastic part in particular may have a thermal conductivity of up to about 5 W / (m · K), in particular of up to about 10 W / (m · K) (in particular for an electrically non-conductive plastic part) and in particular up to about 20 W / (m · K) (especially for an electrically conductive plastic part), or even more. The at least one insert may in particular have an insert whose thermal conductivity is more than 10 W / (m.K), in particular more than 20 W / (m.K), especially more than 50 W / (m.K), and in particular more than 100 W / (m · K).

The insert may be partially surrounded by plastic (thus also partially exposed) or completely surrounded by plastic (core insert).

At least one insert may consist in particular of metal or ceramic. The metal may in particular comprise aluminum, copper, magnesium, steel or a mixture or alloy thereof. The metal insert may in particular be a deep-drawn sheet metal, a section of a metal tube and / or a die-cast part.

As the material of the ceramic, for example SiC, AlN or SiN come into question.

The receiving space is limited or formed in particular only by the first plastic part.

The second plastic part has in particular at least one bearing surface for fastening at least one semiconductor light source. The support surface may in particular be a frontally oriented support surface. The at least one semiconductor light source can be applied directly to a support surface, for example a housed one Semiconductor light source. The at least one semiconductor light source may alternatively rest on a support surface via a carrier (ceramic substrate, printed circuit board, etc.).

The connection of the two plastic parts is in particular a thermal, mechanical and possibly also electrical connection.

As a plastic, in particular thermoplastic can be used, for example PMMA, PC, ABS, PA, PP, PBT, PPS, PEEK, silicone or a mixture thereof. The first plastic part is preferably made of PC or PBT.

It is a development that the two plastic parts have the same plastic as the base material, but one of them has a heat conductivity increasing filler. Alternatively, both plastic parts may have a mutually different heat conductivity increasing filler. For example, graphite or carbon fibers can be used as filling material for an electrically conductive second plastic part. For example, boron nitride particles can be used as filling material for an electrically non-conductive second plastic part.

It is a development that the receiving space is a receiving space for a driver, by means of which the at least one semiconductor light source is operable. The object may thus be a driver, and the receiving space may be at least part of a driver cavity.

It is an embodiment that at least one insert is at least partially inserted between the first plastic part and the second plastic part. Thus, a particularly simple production, in particular in a two-component injection molding, and an effective heat spread at the and discharge from the first plastic part is achieved.

Alternatively or additionally, at least one insert may also be attached at least partially to (including in) the first plastic part or to (including in) the second plastic part.

It is still an embodiment that the receiving space has a cup-shaped basic shape. This allows an effective and circumferentially sealed recording of an object, in particular driver, in the receiving space, and also a simple production. A cup shape may in particular be a circumferentially closed mold.

The receiving space may in particular have a basic shape without undercut in order to enable simple production by injection molding. The receiving space may in particular have a cylindrical, cuboid or dome-shaped basic shape or cup shape.

The receiving space may in particular be connected to an outer side by means of a channel ("cable channel") passing through both plastic parts, in particular for carrying out at least one electrical line to the at least one semiconductor light source.

It is a further embodiment that at least one insert is arranged circumferentially around the receiving space. This further supports heat dissipation from the receiving space.

In yet another embodiment, the second plastic part has a cup-shaped region which opens on the front side, the bottom of which forms a contact surface for the at least one semiconductor light source. This enables a beam direction of the light emitted from the front in the cup-shaped region semiconductor light source (s), in particular if an inside of the cup-shaped region (diffuse or specular) is designed reflective, for example by means of a reflective layer.

The floor is in particular surrounded by a front side upstanding side wall, in particular of a circumferentially closed side wall. The side wall allows increased heat dissipation from the heat sink, in particular by serving as a heat dissipation surface outside.

The front cup-shaped portion has the further advantage that a translucent cover (piston or cover plate, etc.), e.g. made of glass or plastic, easily attachable to it. For this purpose, the front-side cup-shaped region, in particular at its front free edge of the side wall, have at least one recess for receiving the cover, in particular from a lower edge of a piston, e.g. a circumferential annular groove.

It is also an embodiment that the heat sink has an insert, which has a front-opening cup-shaped basic shape. This insert may in particular (only) be arranged on the second plastic part and follow a shape of the front cup-shaped region of the second plastic part. This results in the advantage that an effective and large-scale heat dissipation from the at least one semiconductor light source to the second plastic part, in particular the side wall of the front cup-shaped portion, is made possible, while at the same time a heat flow to the first plastic part can be kept low.

It is also an embodiment that the heat sink has an insert, which has a rear-opening cup-shaped basic shape and the side wall is arranged annularly around the receiving space circumferentially. As a result, at the same time effective and large-area heat dissipation from the at least one semiconductor light source and a heat dissipation from the receiving space can be supported.

It is also an embodiment that at least one insert is exposed at least at the bottom of the cup-shaped region and forms at least part of the support surface. This further reduces a heat transfer resistance between at least one semiconductor light source arranged there and the second plastic part.

It is also an embodiment that the second plastic part at least substantially completely surrounds the first plastic part laterally. As a result, a particularly large heat dissipation surface formed by a lateral, outside surface of the second plastic part is provided. This heat dissipation surface may have a heat dissipation structure, e.g. Cooling ribs, cooling pins, etc. The second plastic part can surround the first plastic part, for example, completely or up to a small support edge.

For a simple production, the heat sink may in particular have a cylindrical, in particular circular cylindrical, outer contour. In particular, the first plastic part may have a reverse "U" -shaped basic shape in longitudinal section and the second plastic part in longitudinal section "H" -shaped basic shape. As a result of the "H" -shaped basic shape of the second plastic part, this has a front-side (front-opening) cup-shaped region and a rearward (rearwardly opening) cup-shaped region, the rear cup-shaped region receiving the first plastic part. Such a heat sink is particularly simple and manufactured.

It is also an embodiment that the first plastic part and the second plastic part are integrally connected to each other. This allows for a special firm connection of the plastic parts. The plastic parts are in particular (large) surface to each other.

It is still an embodiment that the first plastic part and the second plastic part have been produced together by means of a two-component injection molding process. This gives the advantage of a simple and accurate production.

It is yet another embodiment that the first plastic part is electrically insulating. As a result, the advantage is achieved that the receiving space with respect to an environment (eg to maintain air and creepage distances) and also with respect to the second plastic part (in particular for easy electrical isolation against the at least one semiconductor light source) is electrically isolated, which parts, assembly costs and consequently Saves costs.

It is also an embodiment that the second plastic part is electrically conductive. Thus, a simple electrical contacting of the second plastic part is made possible, in addition a particularly high thermal conductivity of up to 20 W / (m · K) or even more. The electrical conductivity of the second plastic part can be achieved in particular by adding an electrically conductive filler material to the plastic base material, e.g. of carbon, electrically conductive metal particles, etc.

It is also an embodiment that the second plastic part is electrically insulating. This avoids contact with potential-carrying parts (especially in the presence of a translucent cover such as a piston) and lengthens creepage distances and clearances.

The object is also achieved by a semiconductor luminescent device with a heat sink as described above.

It is an embodiment that the semiconductor luminescent device is a lamp, in particular a retrofit lamp. The invention can be used particularly advantageously for a lamp, in particular a retrofit lamp, since in this case a particularly compact design with effective heat dissipation is required at a simultaneously low price and low weight.

The retrofit lamp may be, for example, an incandescent retrofit lamp or a halogen lamp retrofit lamp.

In particular, the semiconductor light-emitting device may have a rear-side socket for electrical supply, e.g. an Edison socket or a bipin socket, by means of which the rear opening of the receiving space can be closed. In particular, the driver can be supplied with electrical signals via the base, which the driver converts into operation of the at least one semiconductor light source.

In particular, the semiconductor light-emitting device may have a front-side transparent cover (e.g., a bulb or a cover plate) through which light emitted from the at least one semiconductor light source passes. The cover may in particular be attached to the second plastic part, e.g. through an essay.

The semiconductor luminescent device is in particular equipped with at least one semiconductor light source. Preferably, the at least one semiconductor light source comprises at least one light-emitting diode. If several LEDs are present, they can be lit in the same color or in different colors. A color can be monochrome (eg red, green, blue, etc.) or multichromic (eg be white). The light emitted by the at least one light-emitting diode can also be an infrared light (IR LED) or an ultraviolet light (UV LED). Several light emitting diodes can produce a mixed light; eg a white mixed light. The at least one light-emitting diode may contain at least one wavelength-converting phosphor (conversion LED). The phosphor may alternatively or additionally be arranged remotely from the light-emitting diode ("remote phosphor"). The at least one light-emitting diode can be in the form of at least one individually housed light-emitting diode or in the form of at least one LED chip. Several LED chips can be mounted on a common substrate ("submount"). The at least one light emitting diode may be equipped with at least one own and / or common optics for beam guidance, for example at least one Fresnel lens, collimator, and so on. Instead of or in addition to inorganic light-emitting diodes, for example based on InGaN or AlInGaP, it is generally also possible to use organic LEDs (OLEDs, eg polymer OLEDs). Alternatively, the at least one semiconductor light source may, for example, comprise at least one diode laser.

Fig.1

zeigt als Schnittdarstellung in Seitenansicht einen Kühlkörper einer Halbleiterleuchtvorrichtung gemäß einem ersten Ausführungsbeispiel mit zwei Kunststoffteilen und einer Einlage;

Fig.2

zeigt in einer zu Fig.1 analogen Ansicht einen Kühlkörper gemäß einem zweiten Ausführungsbeispiel mit zwei Kunststoffteilen und zwei Einlagen; und

Fig.3

zeigt in einer zu Fig.1 analogen Ansicht einen Kühlkörper mit zwei Kunststoffteilen ohne Einlagen.

The above-described characteristics, features, and advantages of this invention, as well as the manner in which they will be achieved, will become clearer and more clearly understood in connection with the following schematic description of exemplary embodiments which will be described in detail in conjunction with the drawings. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity.

Fig.1

shows a sectional side view of a heat sink of a semiconductor light emitting device according to a first embodiment with two plastic parts and a liner;

Fig.2

shows in one too Fig.1 analogous view of a heat sink according to a second embodiment with two plastic parts and two deposits; and

Figure 3

shows in one too Fig.1 analog view of a heat sink with two plastic parts without inserts.

Fig.1 shows a heat sink 11 for a semiconductor light fixture H in the form of a filament retrofit lamp.

The heat sink 11 has a first plastic part 12 which has a receiving space 13 which is open on the rear side, and a second plastic part 14 which is connected to the first plastic part 12 on its front side 15. For example, the first plastic part 12 may consist of PC or PBT and have a thermal conductivity of less than 0.6 W / (m · K) and the second plastic part 14 has a thermal conductivity of at least 1 W / (m · K), in particular more than 5 W / (m · K). While the first plastic part 12 is electrically insulating, the second plastic part 14 may be designed to be electrically conductive or electrically insulating.

The first plastic part 12 has a basic shape which is "U" -shaped in a longitudinal section (along the longitudinal axis L), as a result of which the receiving space 13 adopts a cup-shaped, more precisely cylindrical, basic shape which opens backwards or rearwards.

The second plastic part 14 has a longitudinal shape "H" -shaped basic shape, wherein the second plastic part 14, the first plastic part 12 laterally to a rear, laterally projecting support edge 16 completely surrounds. The second plastic part 14 forms a cup-shaped region 17a which opens at the front side (in the direction of the longitudinal axis L) and a cup-shaped region 17b which opens at the rear (against the direction of the longitudinal axis L) and receives the first plastic part 12.

In the heat sink 11 there is a metal insert 18, e.g. a deep-drawn aluminum sheet metal part, which has a higher thermal conductivity (of eg at least 180 W / (m · K)) than the second plastic part 14. The insert 18 has a reversed in the longitudinal section "U" -shaped, cup-like basic shape, which thus at least approximately the shape of the first plastic part 12 and the cup-shaped portion 17b of the second plastic part 14 follows.

The insert 18 lies with its transverse section 19 of the "U" (which is circular disk-shaped or disk-shaped in space) in a planar manner and essentially exposed on the outside on a base 20 of the cup-shaped region 17a. The transverse section 19 and thus also the bottom 20 form a support surface for at least one semiconductor light source (in this case several light emitting diodes 22 arranged on a common carrier 21).

Legs 23 of the "U" are directed vertically downwards and form in space a circular ring around the longitudinal axis L circulating band. The legs 23 and thus also the insert 19 are thus at least partially or in regions arranged annularly around the receiving space 13. The legs 23 extend substantially between the first plastic part 12 and the second plastic part 14. The legs 23 form a side wall of the cup-shaped insert 18th

The first plastic part 12 and the second plastic part 14 are integrally connected to each other, namely, they have been made together by means of a two-component injection molding process, wherein the insert 18 has been partially encapsulated as shown. The insert 18 is thus firmly anchored in the plastic parts 12 and 14. The insert 18 may have holes or other recesses for the passage of plastic in order to facilitate in particular a production of the heat sink 11.

In an upper side 24 of a circumferential side wall 25 of the front-side cup-shaped region 17a of the second plastic part 14, an annular groove 26 for use of a translucent piston B is provided. The piston B vaulted the cup-shaped portion 17a and thus the light emitting diodes 22nd

On the rear side, the receiving space 13 can be closed by a base part S, which here has an Edison socket E as a supply connection. In a driving cavity K formed by the receiving space 13 and the base part S, a driver T is housed, which is the input side to the Edison socket E and the output side connected to the light emitting diodes 22 electrically. The driver T is connected to the LEDs 22 in particular by electrical lines M, which are guided by a concentric to the longitudinal axis through the plastic parts 12 and 14 and through the insert 18 leading (cable) channel 27 and contact the carrier 21, which in turn the LEDs 22 electrically connects to each other.

In operation, the semiconductor light emitting device H, the light emitting diodes 22 are operated via the driver T and thereby waste heat from. The driver T also generates waste heat, albeit to a much lesser degree. The waste heat of the LEDs 22 is largely transmitted with a low thermal resistance to the transverse portion 19 of the insert 18 and forwarded to the legs 23. This results in a large contact surface to the second, good heat-conducting plastic part 14, through which the heat can be further guided on the outside 28 and delivered there to the environment. The outer side 28 here corresponds essentially to the outer lateral side surface of the second plastic part 14, which may have a cooling structure (o.Fig.).

The heat generated in the receiving space 13 or in the driver cavity K can (with a correspondingly higher Thermal resistance) are delivered to the insert 18. At least is prevented by the first plastic part 12 that waste heat from the light emitting diodes 22 of the receiving space 13 and the driver cavity T further heated.

A likewise through the light emitting diodes 22 warming piston chamber R, which is arched by the piston B, can be discharged through the piston B and through the good heat conducting side wall 25 of the cup-shaped portion 17 a therethrough.

Fig.2 shows in one too Fig.1 analogous view of a heat sink 31 according to a second embodiment with two plastic parts 32 and 34 and now two inserts 38 a and 38 b. The heat sink 31 is constructed similarly to the heat sink 11 and, in particular, can be used in a similar manner in a semiconductor light fixture H.

The two inserts 38a and 38b, namely a first insert 38a and a second insert 38b of, for example, aluminum, are spaced from each other and thus thermally more decoupled from one another than a one-piece insert.

Similar to the legs 23 of the insert 18, the first insert 38 a is arranged in a ring around the receiving space 13 and can in particular serve to transfer heat in the receiving space 13 from the first plastic part 32 to the second plastic part 34. Due to the separation from the second insert 38 b, a heat flow from the light emitting diodes 22 to a region of the heat sink 31 is reduced laterally of the receiving space 13, without deteriorating a heat dissipation from the receiving space 13 to the outside, which improves a heat dissipation of the receiving space 13.

The second insert 38b also covers the bottom 20 of the cup-shaped region 17a here, but is only in contact with the second plastic part 34. The second insert 38b points one of the shape of the front cup-shaped portion 17a following, now upwardly opening, cup-shaped basic shape and thereby extends into the side wall 25 of the cup-shaped portion 17a. As a result, the advantage is achieved that the side wall 25 is increasingly used for heat dissipation and overall increased heat dissipation is achieved.

The first plastic part 32 now has no laterally projecting support edge, so that the second plastic part 34 completely surrounds the first plastic part 32 laterally. This is particularly advantageous if the second plastic part 34 is electrically insulating.

Figure 3 shows in one too Fig.1 analogous view of a heat sink 41 with two plastic parts 42 and 44 without deposits. The plastic parts 42 and 44 are formed similarly to the plastic parts 12 and 14. In particular, the second, better heat-conducting plastic part 44 surrounds the first, poorer heat-conducting plastic part 42 laterally substantially (except for the rear support edge (16)).

Although the invention has been further illustrated and described in detail by the illustrated embodiments, the invention is not so limited and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

11

heatsink

12

first plastic part

13

rear open receiving space of the first plastic part 12th

14

second plastic part

15

Front side of the first plastic part 12

16

supporting edge

17a

front-opening cup-shaped region of the second plastic part 14

17b

rear-opening cup-shaped region of the second plastic part 14

18

inlay

19

Cross section of the insert 18

20

Bottom of the cup-shaped portion 17a

21

carrier

22

led

23

leg

24

Top of the circumferential side wall 25th

25

circumferential side wall of the cup-shaped portion 17 a

26

ring groove

27

channel

28

Outside of the second plastic part 14th

31

heatsink

32

first plastic part

34

second plastic part

38a

first deposit

38b

second deposit

41

heatsink

42

first plastic part

44

second plastic part

B

translucent piston

e

Edison socket

H

Semiconductor lighting device

K

Treiberkavität

L

longitudinal axis

M

electrical line

R

piston chamber

S

base part

T

driver

Claims (14)

1. Heat sink (11; 31) for a semiconductor lighting device (H), wherein the heat sink (11; 31) at least comprises:

   - a first plastic part (12; 32), which has a receiving space (13) which is open on the rear side; and

   - a second plastic part (14; 34), which is connected to the first plastic part (12; 32) at the front side (15) of the latter and is intended for the arrangement of at least one semiconductor light source (22), wherein

   - the first plastic part (12; 32) has a lower thermal conductivity than the second plastic part (14; 34) and

   - in the heat sink (11; 31) there is at least one insert (18; 38a, 38b), which has a higher thermal conductivity than the second plastic part (14; 34), characterized in that

   - the insert consists of metal or ceramic and has a thermal conductivity of more than 20 W/(mK), and

   - in that the first plastic part (12; 32) and the second plastic part (14; 34) are connected to one another in one piece.
2. Heat sink (11; 31) according to Claim 1, wherein at least one insert (18; 38a) is at least partially incorporated between the first plastic part (12; 32) and the second plastic part (14; 34).
3. Heat sink (11; 31) according to one of the preceding claims, wherein the receiving space (13) has a cup-shaped basic form.
4. Heat sink (11; 31) according to one of the preceding claims, wherein at least one insert (18; 38a) is arranged running around the receiving space (13) in an annular manner.
5. Heat sink (11; 31) according to one of the preceding claims, wherein the second plastic part (14; 34) has a cup-shaped region (17a) which opens on the front side and the base (20) of which forms a supporting surface for the at least one semiconductor light source (22).
6. Heat sink (31) according to Claim 5, wherein at least one insert (38b), which has a cup-shaped basic form following the form of the cup-shaped region (17a) of the second plastic part (34), is arranged on the second plastic part (34).
7. Heat sink (11) according to Claims 4 and 5, wherein an insert (18) has a cup-shaped basic form which opens on the rear side and the side wall (23) of which is arranged running around the receiving space (13) in an annular manner.
8. Heat sink (11; 31) according to either of Claims 6 and 7, wherein the insert (18; 38b) is exposed at least at the base (20) of the cup-shaped region (17a) and forms at least part of the supporting surface.
9. Heat sink (11; 31) according to one of the preceding claims, wherein the second plastic part (14; 34) laterally surrounds the first plastic part (12; 32) at least substantially completely.
10. Heat sink (11; 31) according to Claim 9, wherein the first plastic part (12; 32) and the second plastic part (14; 34) have been produced together by means of a two-component injection-moulding process.
11. Heat sink (11; 31) according to one of the preceding claims, wherein the first plastic part (12; 32) is electrically insulating.
12. Heat sink (11; 31) according to one of the preceding claims, wherein the second plastic part (14; 34) is electrically conductive or electrically insulating.
13. Semiconductor lighting device (H) with a heat sink (11; 31) according to one of the preceding claims.
14. Semiconductor lighting device (H) according to Claim 13, wherein the semiconductor lighting device (H) is a lamp, in particular a retrofit lamp.

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