Light with cooling fins in the light housing

Abstract

The invention relates to a luminaire comprising a luminaire housing with an interior and a light emission window extending over a horizontal extent, wherein a light source comprising several LEDs 4 is arranged in the interior and a heat sink is arranged in the interior on which the LEDs 4 are arranged.The heat sink has a rib arrangement 20 with several ribs 2, 203, 204, which extends within the horizontal extent of the light emission window, wherein the ribs 2, 203, 204 each abut the side wall 10 of the luminaire housing vertically opposite the light emission window, which defines the interior space, and form gaps between them, wherein the light source rests on the side of the rib arrangement 20 facing the light emission window, and the heat sink is integrally integrated into the side wall 10 defining the interior space, wherein in particular the side wall 10 forms a bottom section of a first, trough-shaped housing part 1 of the luminaire housing, and the light emission window is enclosed by a second housing part designed as a cover.

Description

[0001] The invention relates to a luminaire with a luminaire housing in which a heat sink is arranged, according to the preamble of claim 1.

[0002] Luminaires of this type comprise a housing with an interior and a light-emitting window extending horizontally. A light source with multiple LEDs is arranged within the interior, along with a heat sink on which the LEDs are mounted. This heat sink is necessary to dissipate the heat generated by the LEDs. For this purpose, the LEDs are in thermally conductive contact with the heat sink. Various methods for implementing a luminaire with a heat sink for LEDs are known in the prior art. A very simple yet efficient approach involves providing a highly thermally conductive housing, for example, by manufacturing at least part of the housing from metal, and designing the housing with outward-projecting cooling fins on one side.By mounting the LEDs in the best possible thermally conductive contact on the side of the interior of the luminaire housing, on the exterior of which cooling fins are provided, the luminaire housing can efficiently absorb the heat from the LEDs and dissipate it to the surroundings via the cooling fins. However, this approach has the disadvantage of resulting in a luminaire with a less elegant and difficult-to-clean exterior. This is particularly undesirable for outdoor luminaires, to which the present invention specifically relates. To avoid this undesirable effect, it is also known to provide a flat heat sink, for example, a thick aluminum plate, inside the luminaire housing. The LEDs are arranged on this plate, and it absorbs the heat at the points where the LEDs are mounted and distributes it across its surface.Such a flat heat sink is then thermally connected to the interior walls of the luminaire housing over as large an area as possible, so that it transfers the heat generated by the LEDs to the walls, from where it can be dissipated into the surrounding environment. While this solution avoids the need for cooling fins on the exterior of the luminaire housing, the flat heat sink, as a separate component, must be specifically designed to provide a large mounting surface for the LEDs and to ensure optimal thermal conductivity by connecting to as large an area as possible of the luminaire housing's walls.This increases the manufacturing costs of the luminaire. Furthermore, such a separate heat sink, optimized for heat dissipation, has an unsightly appearance. Therefore, in areas not covered by the LEDs and visible from the outside through the light-emitting window, the heat sink is concealed with additional separate elements. This results in considerable assembly effort and manufacturing costs. Moreover, it is common practice for lighting manufacturers to offer luminaire series where each luminaire has the same housing, but with a different number of LEDs depending on the application. This allows for adjustments to the specific light intensity requirements and ensures that the luminaire does not consume more energy than necessary.This necessitates the use of different cladding materials for different luminaires within such a series, each with a different number of LEDs and thus a different surface area of ​​the light source on the heat sink. This is because different sized areas of the heat sink require cladding to prevent them from being visible through the light-emitting window. This results in even higher manufacturing costs. US Patent 2015 / 0345772 A1 discloses a luminaire with an interior bounded by a side wall that forms cooling fins projecting into the interior. A light source is mounted on these fins. The luminaire has openings through which air can enter the interior from the outside and flow along the fins.KR 101 376 079 B1 discloses a luminaire with a sealed interior bounded by a side wall. This side wall features cooling fins projecting into the interior, on which a light source is mounted, and additional cooling fins on its exterior. These fins allow heat generated by the light source to be transferred from the interior fins to the exterior fins for dissipation into the surrounding environment. US 2018 / 202644 A1 discloses a luminaire with an interior containing fins, and the luminaire has openings through which air can reach the fins from the outside.KR 101 000 014 B1 discloses a luminaire with an interior containing fins on which a light source is arranged, the fins extending to the outside of the luminaire so that the heat generated by the light source can be dissipated to the environment via the fins on the outside. WO 2018 / 214804 A1 discloses a luminaire with a sealed interior containing a heat sink forming a fin arrangement, with a light source having LEDs mounted on the fin arrangement extending across the fin arrangement.

[0003] The present invention is based on the objective of providing a luminaire that at least partially solves at least one of the described problems of luminaires of this type.

[0004] As a solution to the problem underlying the present invention, the invention proposes a luminaire with the features according to claim 1. The luminaire according to the invention comprises a luminaire housing with an interior and a light emission window extending horizontally. Within the interior, a light source with several LEDs is arranged, as is a heat sink on which the LEDs are arranged. The light source is a separate element from the heat sink and is therefore attached to the heat sink during the manufacture of the luminaire. The luminaire according to the invention can have further features in various embodiments, which are explained above in connection with generic luminaires. In the luminaire according to the invention, the heat sink has a fin arrangement with several fins that extends within the horizontal extent of the light emission window.The rib arrangement is, of course, offset vertically from the light-emitting window, since the rib arrangement is located within the interior space and the light-emitting window defines the interior space. However, the rib arrangement extends over at least a portion of the horizontal extent of the light-emitting window, in particular at least 50%, in particular at least 70%, in particular at least 90%, and in particular at least 100% of the horizontal extent of the light-emitting window. The rib arrangement can therefore also extend horizontally beyond the extent of the light-emitting window. It is essential that, as explained, the rib arrangement extends over a significant portion of the horizontal extent of the light-emitting window, since the LEDs are arranged on the rib arrangement and, of course, are preferably aligned with the light-emitting window with respect to the horizontal.Extending the rib arrangement over the largest possible horizontal area offers the advantage that, when viewed from the outside through the light-emitting window, the luminaire presents a uniform appearance defined by the rib arrangement, and that heat is distributed particularly well within the luminaire housing. The ribs rest against the side wall of the luminaire housing that is vertically opposite the light-emitting window and defines the interior space, forming gaps between them. The side wall is preferably a solid surface extending across the horizontal extent of the rib arrangement; more preferably, it extends not only across the horizontal extent of the rib arrangement but also beyond it. This side wall preferably forms a section of the exterior of the luminaire housing on its side facing away from the interior.This allows for particularly efficient heat dissipation to the surroundings via this side wall, on which the ribs are arranged. According to the invention, this side wall has no rib structure on its outer surface; preferably, the entire side of the luminaire housing, vertically opposite the light-emitting window, is designed without a rib structure. The light source is arranged on the side of the rib arrangement facing the light-emitting window and rests on the rib arrangement.Preferably, the light source rests directly on the fin arrangement. However, intermediate elements can also be provided between the fin arrangement and the light source, for example, for mounting purposes. These intermediate elements are preferably highly thermally conductive and extend only within the horizontal dimension of the light source, preferably not over the entire fin arrangement. For both heat conduction and a more aesthetically pleasing appearance of the luminaire, it is particularly advantageous for the light source to rest directly on the cooling fins. According to the invention, the heat sink is integrally integrated into the side wall that defines the interior space and is vertically opposite the light emission window.Accordingly, the fins of the heat sink, which are arranged in the interior, preferably exclusively within the interior, are integrally integrated into the housing part of the luminaire housing that comprises this side wall, and in particular are manufactured directly as a single unit with this housing part of the luminaire housing. The luminaire housing preferably has a first, trough-shaped housing part that includes a bottom section, wherein the bottom section is formed by the side wall, which is vertically opposite the light emission window and defines the interior. Furthermore, the luminaire housing preferably has a second housing part designed as a cover that includes the light emission window. The two housing parts are preferably manufactured in different process steps and, in particular, from different materials.For example, the first housing part can be manufactured by metal casting and the second housing part by injection molding. According to the invention, the housing parts are sealed together to form a sealed interior, preferably sealed according to standard IP64, more preferably IP65.

[0005] The luminaire according to the invention offers significant advantages compared to conventional luminaires. Firstly, the inclusion of a rib arrangement within the interior allows for the creation of a luminaire without external ribs, which contributes to a pleasing overall appearance. Secondly, the rib arrangement ensures good heat distribution within the luminaire housing, enabling heat to be transferred to the side walls that define the interior and dissipated into the surrounding environment. Furthermore, the luminaire according to the invention is particularly easy and cost-effective to manufacture, as the rib arrangement can be easily integrated into the side wall opposite the light-emitting window. It has proven especially advantageous to manufacture the luminaire housing in such a way that it comprises a first housing part designed in the manner of a trough.Components of the luminaire, such as the control gear, power cable, and light source, can be easily mounted in such a housing section, after which the housing section can be easily closed with a cover. It has generally proven particularly preferred to design the rib arrangement such that the spaces between the ribs are open on the side facing the light-emitting window. The ribs of the rib arrangement are particularly preferably designed such that they each have a rib thickness and a rib length with respect to the horizontal and extend over a vertical dimension, with the rib thickness of each rib being at its smallest at the vertical end of the respective rib facing the light-emitting window.This is particularly advantageous for demolding during the manufacture of the housing part, which comprises the side wall defining the interior and the ribs. The ribs preferably form a border around the respective gap they enclose with their vertical end facing the light-exit window. Particularly preferably, the gap is completely closed at its end facing the side wall, which is vertically opposite the light-exit window and borders the interior, with the ribs preferably completely enclosing this gap at this end. Particularly preferably, the gap is open only at its vertical end facing the light-exit window.

[0006] In one embodiment, the ribs of the rib arrangement are arranged in a regular pattern. A honeycomb pattern or other cross-grid pattern is particularly preferred. The regular pattern of the rib arrangement can, firstly, promote a more homogeneous heat distribution; secondly, it is particularly advantageous because an observer from the outside can see the regular pattern through the light-emitting window and perceive it as pleasant when the light source only partially covers the rib arrangement.This is particularly advantageous when the luminaire housing is used to implement different luminaires in a series, since then, regardless of the horizontal extent of the light source of the respective luminaire in the series, an observer from the outside always perceives the horizontal area of ​​the rib arrangement next to the light source as a regular pattern through the light emission window and is therefore visually pleasing.

[0007] In one embodiment, the ribs of the rib arrangement intersect at intersection points. Particularly preferably, the ribs of the rib arrangement merge into one another at these intersection points. Particularly preferably, the intersection points extend over the entire vertical extent of the ribs intersecting at the respective intersection point. Particularly preferably, the intersection points form the corner points of the spaces between the ribs, each of which is horizontally enclosed by the ribs that define it, vertically closed by the side wall opposite the light-exit window that defines the interior, and open on its vertical side facing the light-exit window. The intersection points have a horizontal extent resulting from the crossing or merging of the respective ribs.The appropriate design of the fin arrangement allows for two things: firstly, a robust fin arrangement can be provided, which can also reinforce the housing; secondly, this can ensure particularly good heat distribution; and thirdly, it can guarantee a uniform appearance.

[0008] Generally, the LEDs are preferably arranged along the ribs. Arranging the LEDs along the ribs, i.e., within the horizontal extent of the ribs, ensures particularly good heat dissipation from the LEDs into the ribs, since the LEDs are thus arranged vertically above the ribs and can transfer the heat directly to them. It is particularly preferred that the LEDs are arranged exclusively along the ribs and not along the spaces formed between the ribs.

[0009] According to the invention, the light source is attached to at least some of the ribs. The attachment to the ribs is particularly preferably achieved via fasteners arranged on a side of the ribs facing the light-emitting window to which the light source is attached. For example, the fasteners can comprise bores provided in the ribs or threaded studs integrated into the ribs, with the light source being attached to the ribs, for example, by nuts on the threaded studs or by screws in the bores. It is particularly preferred that the light source is attached exclusively to the ribs. This can be advantageous from a lighting perspective and can also ensure the best possible heat transfer from the light source to the ribs.The rib arrangement is preferably comprised of a first housing part of the luminaire housing in which the light source is arranged, wherein the luminaire housing comprises a second housing part, which is designed as a cover and attached to the first housing part. The second housing part is preferably attached to the first housing part in a sealing and detachable manner. The fastening means are preferably vertically accessible after the second housing part has been removed from the first housing part, on a side of the first housing part that is vertically opposite the light emission window in the luminaire.According to the invention, an optical element arranged between the LEDs and the light-emitting window is further attached to at least some of the ribs, in particular exclusively to the ribs, especially via fastening means arranged on a side of these ribs facing the light-emitting window to which the optical element is attached. It is particularly preferred that the light source and the optical element are attached to the same ribs via the same fastening means. The optical element can be attached to the ribs in various embodiments in an analogous manner to that described with regard to the attachment of the light source to the ribs.

[0010] In one embodiment, the light source is designed as a PCB (printed circuit board) and is directly attached to at least some of the ribs of the rib arrangement. A PCB comprises a substrate on which at least conductive traces and the LEDs are arranged. For example, PCBs are known in which the substrate is designed as a flexible printed circuit board, or PCBs that comprise a printed circuit board with a metal core ("metal-core PCB") or in which a substrate made of an epoxy material is provided. In one embodiment, the light source comprises electrical conductive traces that are applied directly to at least some of the ribs of the rib arrangement. This can be done, for example, by engraving or by printing on the ribs.For example, the ribs can be integrated into a housing part made of metal, with the ribs subsequently coated with an insulating material and then the conductive traces applied to the ribs. Alternatively, the ribs can be integrated into a housing part made of plastic, with the conductive traces applied directly to these plastic ribs.

[0011] According to the invention, the rib arrangement extends with a horizontal section beyond the light source, this horizontal section of the rib arrangement lying within the horizontal extent of the light emission window and, in particular, being at least partially visible from the outside through the light emission window. In this embodiment, the rib arrangement is designed to be so large that it extends beyond the light source with respect to the horizontal and is preferably visible from the outside when viewed through the light emission window. This refers to a viewing angle perpendicular to the horizontal on the light emission window. In this embodiment, the rib arrangement is designed to be large, which enables very good heat distribution.Furthermore, by providing a sufficiently large rib arrangement, an aesthetically pleasing overall impression can be ensured when a viewer looks at the luminaire from the side of the light emission window through the light emission window.

[0012] In one embodiment, the ribs have a thickness and length extending in a horizontal plane, with different thicknesses being provided in different horizontal sections of the rib arrangement. In one embodiment, the thickness and length of each rib are constant over its vertical extent; in another embodiment, these thicknesses can vary along the vertical. In this embodiment, when rib thickness and length vary, the average value over the vertical extent of the respective rib is used. Particularly preferably, the thickness and, in particular, the length of the ribs tapers along the vertical from the side wall opposite the light-exit window towards the light-exit window.A first group of ribs preferably has a greater vertical extent than a second group of ribs, and the first group of ribs has a greater rib thickness than the second group. The rib thickness in a horizontal central region extending around the horizontal center of the light-emitting aperture is particularly preferred, as is the thickness in a horizontal peripheral region arranged horizontally outside the central region. The central region is preferably distributed symmetrically around the horizontal center of the light-emitting aperture. The central region preferably comprises at least 20% of the horizontal extent of the rib arrangement. By providing different rib thicknesses, the heat dissipation desired by each rib can be precisely controlled.

[0013] In one embodiment, the luminaire housing has a vertical height that varies within a region of the horizontal extent of the rib arrangement, specifically across the entire rib arrangement. The vertical extent of the ribs within this region preferably increases to the same degree as the vertical height of the luminaire housing. This ensures that a side of the rib arrangement facing the light-emitting window, formed by the ribs facing the light-emitting window, maintains a constant distance from the window within this region. The rib arrangement thus provides height leveling, ensuring that the light source maintains at least a substantially uniform distance from the light-emitting window across its horizontal extent.

[0014] In general, it is particularly preferred that the side wall vertically opposite the light exit window, together with the rib arrangement, be manufactured in one piece by means of a casting process; it is particularly preferred that the aforementioned first, trough-shaped housing part be manufactured by means of a casting process. This is particularly preferably a metal casting process, in particular a metal die casting process.

[0015] The invention is explained in more detail below using an exemplary embodiment with reference to five figures.

[0016] They show: Figure 1: a schematic representation showing a view of an element of a first embodiment according to the invention; Figure 2: a schematic representation showing a further view of the element according to Figure 1 Figure 3: in a schematic diagram, another view of the element according to Figure 1 Figure 4: a schematic representation showing a view of several elements of the embodiment according to Figure 1 Figure 5: a schematic representation showing a view of several elements of the embodiment according to Figure 1 .

[0017] In the Figures 1 to 5 Various views of different elements of an embodiment of a luminaire according to the invention are shown in schematic diagrams. The following are described below. Figures 1 to 5 jointly explained.

[0018] In the embodiment according to the invention, the luminaire housing has a first housing part 1 which is shaped like a trough. This first housing part 1 has a vertical height along a vertical direction Z, which varies over the horizontal extent of the first housing part 1. The vertical direction is perpendicular to any horizontal plane. As can be seen in particular from Figure 2As can be seen, the first housing part 1 has a vertical top surface onto which a second housing part, designed as a cover and not shown in the figures, can be screwed in a sealing manner. This cover has a light-emitting window that extends within a region of the horizontal extent of the rib arrangement 20, which is integrated into the first housing part 1. Outside the rib arrangement 20, the cover is opaque. The light-emitting window of the cover, or of the second housing part, is located in the Figure 2 The upper surface shown is opposite the luminaire housing in the vertical direction Z. Accordingly, the side wall 10, which forms a bottom section of the trough-shaped first housing part 1, is vertically opposite the light emission window.

[0019] The first housing part 1 incorporates an integrated rib arrangement 20, which has ribs 2 extending vertically from the side wall 10 towards the light exit window and thus towards the top of the first housing part 1. As can be seen in particular from the overall view of the Figures 2 and 3The ribs 2 of the rib arrangement 20 are visibly arranged in a regular cross-lattice pattern. The ribs 2 of the rib arrangement 20 intersect at intersection points 21, where they merge into one another. Four of the ribs 2, which intersect and merge into one another at intersection points 21, enclose a horizontal space. This space is horizontally closed and bounded by these four ribs 2, and on its vertical side opposite the light-exit window, it is bounded by the side wall 10. The space is completely closed except at its vertical end, which faces the light-exit window. For explanatory purposes, the following are shown in the Figures 2 and 3The LEDs 4 are shown so that their positions along the horizontal are visible. This shows that the LEDs 4 are arranged along the ribs 2. Furthermore, it is particularly evident from Figure 3 It is evident that the ribs 2 have a greater thickness in a horizontal central region 201, which extends around the horizontal center of the light emission window, than in a horizontal edge region 202, which is arranged horizontally outside the central region 201. The arrangement of the LEDs 4 along the ribs 2 ensures particularly good heat transfer from the LEDs 4 to the ribs 2. Varying the rib thickness in the different regions 201 and 202 particularly favors heat dissipation from the central region 201, where a particularly high amount of heat is generated, while material costs can be saved by using a thinner rib in the edge region 202.

[0020] In the described embodiment, the LEDs 4 are not arranged directly on the ribs 2 but on a circuit board 40, with the circuit boards 40 together with the LEDs 4 and their other electrical components forming the light source of the described embodiment. This light source is thus placed directly on the vertical side of the ribs 2 facing the light emission window and fixed to the ribs 2. This fixation is achieved by screws 3, which are screwed into threaded holes 22 provided at at least some of the intersection points 21, which is generally particularly advantageous. In the described embodiment, optical elements 5 are also provided between the LEDs 4 and the light emission window, with which the light distribution emitted by the luminaire can be selectively influenced.These optical elements 5 are attached to the ribs 2 by the same fastening means, namely screws 3 and threaded holes 22, with which the circuit boards 40 are also attached.

[0021] The fastening means fix the at least one optical element 5 to the ribs 2 by pressing the optical element 5 vertically onto the light source, thereby pressing the light source onto the vertical side of the ribs 2 facing the light exit window, which is generally advantageous according to the invention.

[0022] Especially from Figure 5It is evident that the ribs 2 of the rib arrangement 20 have different rib lengths along the vertical direction Z in different horizontal areas. For example, rib 204 has a greater extent along the vertical direction Z than rib 203. The vertical extent of ribs 2, 203, and 204 changes in proportion to the increase in the vertical height of the luminaire housing along the horizontal axis. This ensures that the vertical side of ribs 2, 203, and 204 facing the light emission window maintains a uniform distance from the window, so that all LEDs 4 have essentially the same vertical distance from the window. Reference symbol list

[0023] 1. First housing part 2. Rib 3. Screw 4. LED 5. Optical element 10. Side wall 20. Rib arrangement 21. Intersection point 22. Threaded hole 40. Circuit board 201. Horizontal center area 202. Horizontal edge area 203. Rib 204. Rib Z - Vertical direction

Claims

1. Light comprising a light housing with an interior space and a light emission window extending over a horizontal extent, wherein an illuminant comprising a plurality of LEDs (4) is arranged in the interior space and a heat sink on which the LEDs (4) are arranged is arranged in the interior space, wherein the heat sink has a rib arrangement (20) with a plurality of fins (2, 203, 204), which extends within the horizontal extent of the light emission window, wherein the fins (2, 203, 204) each bear against the side wall (10) of the light housing which is vertically opposite the light emission window and bounds the interior space and form intermediate spaces between them, wherein the illuminant rests on the side of the rib arrangement (20) facing the light emission window, wherein the heat sink arranged in the interior space is integrated in one piece in the side wall (10) bounding the interior space and this side wall (10) does not have a rib structure on its outer side, the side wall (10) forming a bottom section of a first, trough-shaped housing part (1) of the light housing and the light emission window being enclosed by a second housing part designed as a cover, the housing parts (1) being connected to one another in a sealing manner, forming the interior space as a sealed interior space, characterized in that the rib arrangement (20) extends with a horizontal section beyond the illuminant, this horizontal section of the rib arrangement (20) lying within the horizontal extension of the light emission window, wherein the illuminant and an optical element (5), which is arranged between the LEDs (4) and the light emission window, are mounted on at least some of the fins (2, 203, 204), in particular by fixing means (3,22), which are arranged on a side of these fins (2, 203, 204) facing the light emission window.

2. Light according to claim 1, characterized in that the fins (2, 203, 204) of the rib arrangement (20) are arranged to form a regular pattern, the pattern being in particular a honeycomb pattern or other cross-grid pattern.

3. Light according to any of the preceding claims, characterized in that the fins (2, 203, 204) of the rib arrangement (20) intersect at intersection points (21), wherein in particular the intersection points (21) each form the corner points of the intermediate spaces between the fins (2, 203, 204) and each of the intermediate spaces is horizontally circumferentially enclosed by the fins (2, 203, 204) bounding it, is vertically closed by the side wall (10) opposite the light emission window and is open on its vertical side facing the light emission window.

4. Light according to any of the preceding claims, characterized in that the LEDs (4) are arranged along the fins (2, 203, 204).

5. Light according to one of the preceding claims, characterized in that the illuminant is formed as a PCB and is directly attached to at least some fins (2, 203, 204) of the rib arrangement (20) or that the illuminant comprises electrical conductor tracks which are directly applied to at least some fins (2, 203, 204) of the rib arrangement (20).

6. Light according to any of the preceding claims, characterized in that the horizontal portion of the rib arrangement (20), with which it extends beyond the illuminant, is visible from the outside through the light emission window.

7. Light according to any one of the preceding claims, characterized in that the fins (2, 203, 204) have a rib thickness and a rib length over which they extend horizontally, different rib thicknesses being respectively provided in different horizontal sections of the rib arrangement (20), the rib thickness of the fins (2, 203, 204) in particular being greater in a horizontal center region (201) extending around the horizontal center of the light exit opening than in a horizontal edge region (202) arranged horizontally on the outside of the center region (201).

8. Light according to any one of the preceding claims, characterized in that the light housing has a vertical height which varies within a region of the horizontal extension of the rib arrangement (20), wherein a vertical extension of the fins (2, 203, 204) of the rib arrangement (20) increases within this region to the same extent as the vertical height of the light housing, so that a side of the rib arrangement (20) facing the light emission window, which is formed by the side of the fins (2, 203, 204) facing the light emission window, has a constant distance to the light emission window within this region.

9. Light according to any of the preceding claims, characterized in that the side wall (10) together with the rib arrangement (20), in particular the first, trough-shaped housing part (1), is produced in one piece by means of a casting process, in particular a metal casting process.

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